The UK's National Institute for Health and Care Excellence (NICE) recently proposed amendments to its methods for the appraisal of health technologies. Previous amendments in 2009 and 2011 placed a greater value on the health of patients at the "end of life" and in cases where "treatment effects are both substantial in restoring health and sustained over a very long period". Drawing lessons from these previous amendments, we critically appraise NICE's proposals. The proposals repeal "end of life" considerations but add consideration of the "proportional" and "absolute" quality-adjusted life-year (QALY) loss from illness. NICE's cost-effectiveness threshold may increase from £20,000 to £50,000 per QALY on the basis of these and four other considerations: the "certainty of the ICER [incremental cost-effectiveness ratio]"; whether health-related quality of life is "inadequately captured"; the "innovative nature" of the technology; and "non-health objectives of the NHS". We demonstrate that NICE's previous amendments are flawed; they contain logical inconsistencies which can result in different values being placed on health gains for identical patients, and they do not apply value weights to patients bearing the opportunity cost of NICE's recommendations. The proposals retain both flaws and are also poorly justified. Applying value weights to patients bearing the opportunity cost would lower NICE's threshold, in some cases to below £20,000 per QALY. Furthermore, this baseline threshold is higher than current estimates of the opportunity cost. NICE's proposed threshold range is too high, for empirical and methodological reasons. NICE's proposals will harm the health of unidentifiable patients, whilst privileging the identifiable beneficiaries of new health technologies.
The PTTG1-binding factor (PBF/PTTG1IP) has an emerging repertoire of roles, especially in thyroid biology, and functions as a protooncogene. High PBF expression is independently associated with poor prognosis and lower disease-specific survival in human thyroid cancer. However, the precise role of PBF in thyroid tumorigenesis is unclear. Here, we present extensive evidence demonstrating that PBF is a novel regulator of p53, a tumor suppressor protein with a key role in maintaining genetic stability, which is infrequently mutated in differentiated thyroid cancer. By coimmunoprecipitation and proximity-ligation assays, we show that PBF binds specifically to p53 in thyroid cells and significantly represses transactivation of responsive promoters. Further, we identify that PBF decreases p53 stability by enhancing ubiquitination, which appears dependent on the E3 ligase activity of Mdm2. Impaired p53 function was evident in a transgenic mouse model with thyroid-specific PBF overexpression (transgenic PBF mice), which had significantly increased genetic instability as indicated by fluorescent inter simple sequence repeat-PCR analysis. Consistent with this, approximately 40% of all DNA repair genes examined were repressed in transgenic PBF primary cultures, including genes with critical roles in maintaining genomic integrity such as Mgmt, Rad51, and Xrcc3. Our data also revealed that PBF induction resulted in up-regulation of the E2 enzyme Rad6 in murine thyrocytes and was associated with Rad6 expression in human thyroid tumors. Overall, this work provides novel insights into the role of the protooncogene PBF as a negative regulator of p53 function in thyroid tumorigenesis, in which PBF is generally overexpressed and p53 mutations are rare compared with other tumor types.
The arrival of personalized medicine in the clinic means that treatment decisions will increasingly rely on test results. The challenge of limited healthcare resources means that the dissemination of these technologies will be dependent on their value in relation to their cost, i.e., their cost effectiveness. Phelps and Mushlin have described how to optimize tests to meet a cost-effectiveness target. However, when tests are applied repeatedly the case mix of the patients tested changes with each administration, and this impacts upon the value of each subsequent test administration. In this article, we present a modification of Phelps and Mushlin's framework for diagnostic tests; to identify the cost-effective cut-off for monitoring tests. Using the Ca125 test monitoring for relapse in ovarian cancer, we show how the repeated use of the initial cut-off can lead to a substantially increased false-negative rate compared with the monitoring cut-off-over 4% higher than in this example-with the associated harms for individual and population health.
The challenge of implementing high-cost innovative technologies in health care systems operating under significant budgetary pressure has led to a radical shift in the health technology reimbursement landscape. New reimbursement strategies attempt to reduce the risk of making the wrong decision, that is, paying for a technology that is not good value for the health care system, while promoting the adoption of innovative technologies into clinical practice. The remaining risk, however, is not shared between the manufacturer and the health care payer at the individual purchase level; it continues to be passed from the manufacturer to the payer at the time of purchase. In this article, we propose a health technology payment strategy-technology leasing reimbursement scheme-that allows the sharing of risk between the manufacturer and the payer: the replacing of up-front payments with a stream of payments spread over the expected duration of benefit from the technology, subject to the technology delivering the claimed health benefit. Using trastuzumab (Herceptin) in early breast cancer as an exemplar technology, we show how a technology leasing reimbursement scheme not only reduces the total budgetary impact of the innovative technology but also truly shares risk between the manufacturer and the health care system, while reducing the value of further research and thus promoting the rapid adoption of innovative technologies into clinical practice.
Acute ischemic stroke is common and disabling, but there remains a paucity of acute treatment options and available treatment (thrombolysis) is underutilized. Advanced brain imaging, designed to identify viable hypoperfused tissue (penumbra), could target treatment to a wider population. Existing magnetic resonance imaging and computed tomography-based technologies are not widely used pending validation in ongoing clinical trials. T2* oxygen challenge magnetic resonance imaging, by providing a more direct readout of tissue viability, has the potential to identify more patients likely to benefit from thrombolysis - irrespective of time from stroke onset - and patients within and beyond the 4·5?h thrombolysis treatment window who are unlikely to benefit and are at an increased risk of hemorrhage.
Abstract Despite high expectations of economic returns, large investments in regenerative medicine technology have yet to materialize, partly due to a lack of proven business and investment models, regulatory hurdles, and a greater focus on cost-effectiveness for reimbursement decisions by payors. Adoption of new economic modeling methods will better link investment decisions to value-based criteria of health systems.
The cost of whole genome sequencing is dropping rapidly. There has been a great deal of enthusiasm about the potential for this technological advance to transform clinical care. Given the interest and significant investment in genomics, this seems an ideal time to consider what the evidence tells us about potential benefits and harms, particularly in the context of health care policy. The scale and pace of adoption of this powerful new technology should be driven by clinical need, clinical evidence, and a commitment to put patients at the centre of health care policy.
Healthcare systems are increasingly under pressure to provide funding for innovative technologies. These technologies tend to be characterized by their potential to make valued contributions to patient health in areas of relative unmet need, and have high acquisition costs and uncertainty within the evidence base on their actual impact on health. Decision makers are increasingly interested in linking reimbursement strategies to the degree of uncertainty in the evidence base and, as a result, reimbursement for innovative technologies is frequently linked to some form of patient access or risk-sharing scheme. As the dominant methods of economic evaluation report final outcomes only at the time horizon of the analysis, they present only aggregated information. This omits much of the information available on how net benefit is distributed within the time horizon. In this article, we introduce the Net Benefit Probability Map (NBPM), which maps net health benefit versus time to identify how certain decision makers can be about the benefit of technologies at multiple time points. Using an illustrative example, we show how the NBPM can inform decision makers about how long it will take for innovative technologies to pay off, how methodological choices on discount rates affect results and how alternative payment mechanisms can reduce the risk for decision makers facing innovative technologies.
Human pituitary tumor transforming gene (hPTTG) is a multifunctional proto-oncogene implicated in the initiation and progression of several tumors. Phosphorylation of hPTTG is mediated by cyclin-dependent kinase 2 (CDC2), whereas cellular expression is regulated by specificity protein 1 (SP1). The mechanisms underlying hPTTG propagation of aberrant thyroid cell growth have not been fully defined. We set out to investigate the interplay between hPTTG and growth factors, as well as the effects of phosphorylation and SP1 regulation on hPTTG expression and function. In our study, epidermal growth factor (EGF), TGF?, and IGF-1 induced hPTTG expression and phosphorylation in thyroid cells, which was associated with activation of MAPK and phosphoinositide 3-kinase. Growth factors induced hPTTG independently of CDC2 and SP1 in thyroid carcinoma cells. Strikingly, CDC2 depletion in TPC-1 cells resulted in enhanced expression and phosphorylation of hPTTG and reduced cellular proliferation. In reciprocal experiments, hPTTG overexpression induced EGF, IGF-1, and TGF? mRNAs in primary human thyrocytes. Treatment of primary human thyrocytes with conditioned media derived from hPTTG-transfected cells resulted in autocrine upregulation of hPTTG protein, which was ameliorated by growth factor depletion or growth factor receptor tyrosine kinase inhibitors. A transgenic murine model of thyroid targeted hPTTG overexpression (hPTTG-Tg) (FVB/N strain, both sexes) demonstrated smaller thyroids with reduced cellular proliferation and enhanced secretion of Egf. In contrast, Pttg(-/-) knockout mice (c57BL6 strain, both sexes) showed reduced thyroidal Egf mRNA expression. These results define hPTTG as having a central role in thyroid autocrine signaling mechanisms via growth factors, with profound implications for promotion of transformed cell growth.
The construction of mapping models is an increasingly popular mechanism for obtaining health state utility data to inform economic evaluations in health care. There is great variation in the sophistication of the methods utilized but to date very little discussion of the appropriate theoretical framework to guide the design and evaluation of these models. In this paper, we argue that recognizing mapping models as a form of indirect health state valuation allows the use of the framework described by Dolan for the measurement of social preferences over health. Using this framework, we identify substantial concerns with the method for valuing health states that is implicit in indirect utility models (IUMs), the conflation of two sets of respondents values in such models, and the lack of a structured and statistically reasonable approach to choosing which states to value and how many observations per state to require in the estimation dataset. We also identify additional statistical challenges associated with clustering and censoring in the datasets for IUMs, additional to those attributable to the descriptive systems, and a potentially significant problem with the systematic understatement of uncertainty in predictions from IUMs. Whilst recognizing that IUMs appear to meet the needs of reimbursement organizations that use quality-adjusted life years in their appraisal processes, we argue that current proposed quality standards are inadequate and that IUMs are neither robust nor appropriate mechanisms for estimating utilities for use in cost-effectiveness analyses.
Poststroke hyperglycemia is associated with a poor outcome yet clinical management is inadequately informed. We sought to determine whether clinically relevant levels of hyperglycemia exert detrimental effects on the early evolution of focal ischemic brain damage, as determined by magnetic resonance imaging, in normal rats and in those modeling the metabolic syndrome. Wistar Kyoto (WKY) or fructose-fed spontaneously hypertensive stroke-prone (ffSHRSP) rats were randomly allocated to groups for glucose or vehicle administration before permanent middle cerebral artery occlusion. Diffusion-weighted imaging was carried out over the first 4 hours after middle cerebral artery occlusion and lesion volume calculated from apparent diffusion coefficient maps. Infarct volume and immunostaining for markers of oxidative stress were measured in the fixed brain sections at 24 hours. Hyperglycemia rapidly exacerbated early ischemic damage in both WKY and ffSHRSP rats but increased infarct volume only in WKY rats. There was only limited evidence of oxidative stress in hyperglycemic animals. Acute hyperglycemia, at clinically relevant levels, exacerbates early ischemic damage in both normal and metabolic syndrome rats. Management of hyperglycemia may have greatest benefit when performed in the acute phase after stroke in the absence or presence of comorbidities.
We hypothesized that targeting key points in the ischemic cascade with combined neuroglobin (Ngb) overexpression and c-jun N-terminal kinase (JNK) inhibition (SP600125) would offer greater neuroprotection than single treatment after in vitro hypoxia/reoxygenation and in a randomized, blinded in vivo experimental stroke study using a clinically relevant rat strain. Male spontaneously hypertensive stroke-prone rats underwent transient middle cerebral artery occlusion (tMCAO) and were divided into the following groups: tMCAO; tMCAO+control GFP-expressing canine adenovirus-2, CAVGFP; tMCAO+Ngb-expressing CAV-2, CAVNgb; tMCAO+SP600125; tMCAO+CAVNgb+SP600125; or sham procedure. Rats were assessed till day 14 for neurologic outcome before infarct determination. In vitro, combined lentivirus-mediated Ngb overexpression+SP600125 significantly reduced oxidative stress and apoptosis compared with single treatment(s) after hypoxia/reoxygenation in B50 cells. In vivo, infarct volume was significantly reduced by CAVNgb, SP600125, and further by CAVNgb+SP600125. The number of Ngb-positive cells in the peri-infarct cortex and striatum was significantly increased 14 days after tMCAO in animals receiving CAVNgb. Neurologic outcome, measured using a 32-point neurologic score, significantly improved with CAVNgb+SP600125 compared with single treatments at 14 days after tMCAO. Combined Ngb overexpression with JNK inhibition reduced hypoxia/reoxygenation-induced oxidative stress and apoptosis in cultured neurons and reduced infarct and improved neurologic outcome more than single therapy after in vivo experimental stroke in hypertensive rats.
Hypertension is associated with cerebral small vessel disease (SVD) and with diffuse white matter hyperintensities (WMH) on T2-weighted magnetic resonance imaging (MRI). We tested whether stroke-prone spontaneously hypertensive rats (SHRSP), a model of chronic hypertension, exhibit WMH. Male SHRSP (age 10 months) without stroke symptoms were compared with age-matched male WKY rats. Stroke-prone spontaneously hypertensive rats exhibited no WMH on MRI scans (T2, T2*, diffusion tensor imaging) and no neuropathological lesions. While leptomeningeal arteries exhibited fibrohyaline wall thickening, with decreased smooth muscle actin relative to WKY, deep penetrating arterioles within the caudate nuclei had no vasculopathy. We conclude that WMH are not an obligate feature of stroke-free SHRSP aged up to 10 months.
We summarise and evaluate Harris criticisms of cost-effectiveness analysis (CEA) and the alternative processes he commends to health care decision makers. In contrast to CEA, Harris asserts that individuals have a right to life-saving treatment that cannot be denied on the basis of their capacity to benefit. We conclude that, whilst Harris work has challenged the proponents of CEA and quality-adjusted life years to be explicit about the methods indirect discriminatory characteristics, his arguments ignore important questions about what lives saved mean. Harris also attempts to avoid opportunity cost by advocating the same chance of treatment for every person desiring treatment. Using a simple example, we illustrate that an equal chances lottery is not in the interest of any patient, as it reduces the chance of treatment for all patients by leaving some of the health budget unspent.
Monocarboxylate transporter 8 (MCT8) is a well-established thyroid hormone (TH) transporter. In humans, MCT8 mutations result in changes in circulating TH concentrations and X-linked severe global neurodevelopmental delay. MCT8 is expressed in the human placenta throughout gestation, with increased expression in trophoblast cells from growth-restricted pregnancies. We postulate that MCT8 plays an important role in placental development and transplacental TH transport. We investigated the effect of altering MCT8 expression in human trophoblast in vitro and in a Mct8 knockout mouse model. Silencing of endogenous MCT8 reduced T3 uptake into human extravillous trophoblast-like cells (SGHPL-4; 40%, P<0.05) and primary cytotrophoblast (15%, P<0.05). MCT8 over-expression transiently increased T3 uptake (SGHPL-4?30%, P<0.05; cytotrophoblast: 15%, P<0.05). Silencing MCT8 did not significantly affect SGHPL-4 invasion, but with MCT8 over-expression T3 treatment promoted invasion compared with no T3 (3.3-fold; P<0.05). Furthermore, MCT8 silencing increased cytotrophoblast viability (?20%, P<0.05) and MCT8 over-expression reduced cytotrophoblast viability independently of T3 (?20%, P<0.05). In vivo, Mct8 knockout reduced fetal:placental weight ratios compared with wild-type controls at gestational day 18 (25%, P<0.05) but absolute fetal and placental weights were not significantly different. The volume fraction of the labyrinthine zone of the placenta, which facilitates maternal-fetal exchange, was reduced in Mct8 knockout placentae (10%, P<0.05). However, there was no effect on mouse placental cell proliferation in vivo. We conclude that MCT8 makes a significant contribution to T3 uptake into human trophoblast cells and has a role in modulating human trophoblast cell invasion and viability. In mice, Mct8 knockout has subtle effects upon fetoplacental growth and does not significantly affect placental cell viability probably due to compensatory mechanisms in vivo.
The ability of adenovirus early region proteins, E1B-55K and E4orf6, to usurp control of cellular ubiquitin ligases and target proteins for proteasome-dependent degradation during infection is well established. Here we show that the E4 gene product, E4orf3 can, independently of E1B-55K and E4orf6, target the transcriptional corepressor transcriptional intermediary factor 1? (TIF1?) for proteasome-mediated degradation during infection. Initial mass spectrometric studies identified TIF1 family members-TIF1?, TIF1?, and TIF1?-as E1B-55K-binding proteins in both transformed and infected cells, but analyses revealed that, akin to TIF1?, TIF1? is reorganized in an E4orf3-dependent manner to promyelocytic leukemia protein-containing nuclear tracks during infection. The use of a number of different adenovirus early region mutants identified the specific and sole requirement for E4orf3 in mediating TIF1? degradation. Further analyses revealed that TIF1? is targeted for degradation by a number of divergent human adenoviruses, suggesting that the ability of E4orf3 to regulate TIF1? expression is evolutionarily conserved. We also determined that E4orf3 does not utilize the Cullin-based ubiquitin ligases, CRL2 and CRL5, or the TIF1? ubiquitin ligase in order to promote TIF1? degradation. Further studies suggested that TIF1? possesses antiviral activity and limits adenovirus early and late gene product expression during infection. Indeed, TIF1? knockdown accelerates the adenovirus-mediated degradation of MRE11, while TIF1? overexpression delays the adenovirus-mediated degradation of MRE11. Taken together, these studies have identified novel adenovirus targets and have established a new role for the E4orf3 protein during infection.
Multi-parameter genomic tests identify patients with early-stage breast cancer who are likely to derive little benefit from adjuvant chemotherapy. These tests can potentially spare patients the morbidity from unnecessary chemotherapy and reduce costs. However, the costs of the test must be balanced against the health benefits and cost savings produced. This economic evaluation compared genomic test-directed chemotherapy using the Oncotype DX 21-gene assay with chemotherapy for all eligible patients with lymph node-positive, estrogen receptor-positive early-stage breast cancer.
There is growing enthusiasm for robotic-assisted laparoscopic operations across many surgical specialities, including colorectal surgery, often not supported by robust clinical or cost-effectiveness data. A proper assessment of this new technology is required, prior to widespread recommendation or implementation.
The purpose of this study was to compare centralized reimbursement/coverage decision-making processes for health technologies in 23 European countries, according to: mandate, authority, structure, and policy options; mechanisms for identifying, selecting, and evaluating technologies; clinical and economic evidence expectations; committee composition, procedures, and factors considered; available conditional reimbursement options for promising new technologies; and the manufacturers roles in the process.
Pituitary tumor transforming gene (PTTG)-binding factor (PBF or PTTG1IP) is a little characterized proto-oncogene that has been implicated in the etiology of breast and thyroid tumors. In this study, we created a murine transgenic model to target PBF expression to the thyroid gland (PBF-Tg mice) and found that these mice exhibited normal thyroid function, but a striking enlargement of the thyroid gland associated with hyperplastic and macrofollicular lesions. Expression of the sodium iodide symporter (NIS), a gene essential to the radioiodine ablation of thyroid hyperplasia, neoplasia, and metastasis, was also potently inhibited in PBF-Tg mice. Critically, iodide uptake was repressed in primary thyroid cultures from PBF-Tg mice, which could be rescued by PBF depletion. PBF-Tg thyroids exhibited upregulation of Akt and the TSH receptor (TSHR), each known regulators of thyrocyte proliferation, along with upregulation of the downstream proliferative marker cyclin D1. We extended and confirmed findings from the mouse model by examining PBF expression in human multinodular goiters (MNG), a hyperproliferative thyroid disorder, where PBF and TSHR was strongly upregulated relative to normal thyroid tissue. Furthermore, we showed that depleting PBF in human primary thyrocytes was sufficient to increase radioiodine uptake. Together, our findings indicate that overexpression of PBF causes thyroid cell proliferation, macrofollicular lesions, and hyperplasia, as well as repression of the critical therapeutic route for radioiodide uptake.
Attempts to improve the acceptability of resource allocation decisions around new health technologies have spanned many years, fields and disciplines. Various theories of decision making have been tested and methods piloted, but, despite their availability, evidence of sustained uptake is limited. Since the challenge of determining which of many technologies to fund is one that healthcare systems have faced since their inception, an analysis of actual processes, criticisms confronted and approaches used to manage them may serve to guide the development of an evidence-informed decision-making framework for improving the acceptability of decisions.
Human African trypanosomiasis (HAT), or sleeping sickness, results from infection with the protozoan parasites Trypanosoma brucei (T. b.) gambiense or T. b. rhodesiense and is invariably fatal if untreated. There are 60 million people at risk from the disease throughout sub-Saharan Africa. The infection progresses from the haemolymphatic stage where parasites invade the blood, lymphatics and peripheral organs, to the late encephalitic stage where they enter the central nervous system (CNS) to cause serious neurological disease. The trivalent arsenical drug melarsoprol (Arsobal) is the only currently available treatment for CNS-stage T. b. rhodesiense infection. However, it must be administered intravenously due to the presence of propylene glycol solvent and is associated with numerous adverse reactions. A severe post-treatment reactive encephalopathy occurs in about 10% of treated patients, half of whom die. Thus melarsoprol kills 5% of all patients receiving it. Cyclodextrins have been used to improve the solubility and reduce the toxicity of a wide variety of drugs. We therefore investigated two melarsoprol cyclodextrin inclusion complexes; melarsoprol hydroxypropyl-?-cyclodextrin and melarsoprol randomly-methylated-?-cyclodextrin. We found that these compounds retain trypanocidal properties in vitro and cure CNS-stage murine infections when delivered orally, once per day for 7-days, at a dosage of 0.05 mmol/kg. No overt signs of toxicity were detected. Parasite load within the brain was rapidly reduced following treatment onset and magnetic resonance imaging showed restoration of normal blood-brain barrier integrity on completion of chemotherapy. These findings strongly suggest that complexed melarsoprol could be employed as an oral treatment for CNS-stage HAT, delivering considerable improvements over current parenteral chemotherapy.
All healthcare systems routinely make resource allocation decisions that trade off potential health gains to different patient populations. However, when such trade-offs relate to the introduction of new, promising health technologies, perceived winners and losers are more apparent. In recent years, public scrutiny over such decisions has intensified, raising the need to better understand how they are currently made and how they might be improved. The objective of this paper is to critically review and compare current processes for making health technology funding decisions at the regional, state/provincial and national level in 20 countries. A comprehensive search for published, peer-reviewed and grey literature describing actual national, state/provincial and regional/institutional technology decision-making processes was conducted. Information was extracted by two independent reviewers and tabulated to facilitate qualitative comparative analyses. To identify strengths and weaknesses of processes identified, websites of corresponding organizations were searched for commissioned reviews/evaluations, which were subsequently analysed using standard qualitative methods. A total of 21 national, four provincial/state and six regional/institutional-level processes were found. Although information on each one varied, they could be grouped into four sequential categories: (i) identification of the decision problem; (ii) information inputs; (iii) elements of the decision-making process; and (iv) public accountability and decision implementation. While information requirements of all processes appeared substantial and decision-making factors comprehensive, the way in which they were utilized was often unclear, as were approaches used to incorporate social values or equity arguments into decisions. A comprehensive inventory of approaches to implementing the four main components of all technology funding decision-making processes was compiled, from which areas for future work or research aimed at improving the acceptability of decisions were identified. They include the explication of decision criteria and social values underpinning processes.
Accurate identification of ischemic penumbra will improve stroke patient selection for reperfusion therapies and clinical trials. Current magnetic resonance imaging (MRI) techniques have limitations and lack validation. Oxygen challenge T(2)(*) MRI (T(2)(*) OC) uses oxygen as a biotracer to detect tissue metabolism, with penumbra displaying the greatest T(2)(*) signal change during OC. [(14)C]2-deoxyglucose (2-DG) autoradiography was combined with T(2)(*) OC to determine metabolic status of T(2)(*)-defined penumbra. Permanent middle cerebral artery occlusion was induced in anesthetized male Sprague-Dawley rats (n=6). Ischemic injury and perfusion deficit were determined by diffusion- and perfusion-weighted imaging, respectively. At 147 ± 32 minutes after stroke, T(2)(*) signal change was measured during a 5-minute 100% OC, immediately followed by 125 ?Ci/kg 2-DG, intravenously. Magnetic resonance images were coregistered with the corresponding autoradiograms. Regions of interest were located within ischemic core, T(2)(*)-defined penumbra, equivalent contralateral structures, and a region of hyperglycolysis. A T(2)(*) signal increase of 9.22% ± 3.9% (mean ± s.d.) was recorded in presumed penumbra, which displayed local cerebral glucose utilization values equivalent to contralateral cortex. T(2)(*) signal change was negligible in ischemic core, 3.2% ± 0.78% in contralateral regions, and 1.41% ± 0.62% in hyperglycolytic tissue, located outside OC-defined penumbra and within the diffusion abnormality. The results support the utility of OC-MRI to detect viable penumbral tissue following stroke.
Accurate imaging of the ischemic penumbra is a prerequisite for acute clinical stroke research. T(2)(*) magnetic resonance imaging (MRI) combined with an oxygen challenge (OC) is being developed to detect penumbra based on changes in blood deoxyhemoglobin. However, inducing OC with 100% O(2) induces sinus artefacts on human scans and influences cerebral blood flow (CBF), which can affect T(2)(*) signal. Therefore, we investigated replacing 100% O(2) OC with 40% O(2) OC (5 minutes 40% O(2) versus 100% O(2)) and determined the effects on blood pressure (BP), CBF, tissue pO(2), and T(2)(*) signal change in presumed penumbra in a rat stroke model. Probes implanted into penumbra and contralateral cortex simultaneously recorded pO(2) and CBF during 40% O(2) (n=6) or 100% O(2) (n=8) OC. In a separate MRI study, T(2)(*) signal change to 40% O(2) (n=6) and 100% O(2) (n=5) OC was compared. Oxygen challenge (40% and 100% O(2)) increased BP by 8.2% and 18.1%, penumbra CBF by 5% and 15%, and penumbra pO(2) levels by 80% and 144%, respectively. T(2)(*) signal significantly increased by 4.56% ± 1.61% and 8.65% ± 3.66% in penumbra compared with 2.98% ± 1.56% and 2.79% ± 0.66% in contralateral cortex and 1.09% ± 0.82% and -0.32% ± 0.67% in ischemic core, respectively. For diagnostic imaging, 40% O(2) OC could provide sufficient T(2)(*) signal change to detect penumbra with limited influence in BP and CBF.
Magnetic resonance imaging (MRI) with oxygen challenge (T(2)(*) OC) uses oxygen as a metabolic biotracer to define penumbral tissue based on CMRO(2) and oxygen extraction fraction. Penumbra displays a greater T(2)(*) signal change during OC than surrounding tissue. Since timely restoration of cerebral blood flow (CBF) should salvage penumbra, T(2)(*) OC was tested by examining the consequences of reperfusion on T(2)(*) OC-defined penumbra. Transient ischemia (109 ± 20 minutes) was induced in male Sprague-Dawley rats (n=8). Penumbra was identified on T(2)(*)-weighted MRI during OC. Ischemia and ischemic injury were identified on CBF and apparent diffusion coefficient maps, respectively. Reperfusion was induced and scans repeated. T(2) for final infarct and T(2)(*) OC were run on day 7. T(2)(*) signal increase to OC was 3.4% in contralateral cortex and caudate nucleus and was unaffected by reperfusion. In OC-defined penumbra, T(2)(*) signal increased by 8.4% ± 4.1% during ischemia and returned to 3.25% ± 0.8% following reperfusion. Ischemic core T(2)(*) signal increase was 0.39% ± 0.47% during ischemia and 0.84% ± 1.8% on reperfusion. Penumbral CBF increased from 41.94 ± 13 to 116.5 ± 25 mL per 100 g per minute on reperfusion. On day 7, OC-defined penumbra gave a normal OC response and was located outside the infarct. T(2)(*) OC-defined penumbra recovered when CBF was restored, providing further validation of the utility of T(2)(*) OC for acute stroke management.
Trastuzumab has significantly improved survival outcomes for women with Human Epidermal growth factor Receptor 2 (HER2)-positive early breast cancer. Trastuzumab was established as a cost-effective adjuvant treatment in 2006. We present an updated cost-effectiveness analysis from the UK perspective, which explores assumptions about the duration of benefit from treatment, pattern of metastatic recurrence and long-term cardiac toxicity.
Pituitary tumor-transforming gene (PTTG)-binding factor (PBF; PTTG1IP) was initially identified through its interaction with the human securin, PTTG. Like PTTG, PBF is upregulated in multiple endocrine tumours including thyroid cancer. PBF is believed to induce the translocation of PTTG into the cell nucleus where it can drive tumourigenesis via a number of different mechanisms. However, an independent transforming ability has been demonstrated both in vitro and in vivo, suggesting that PBF is itself a proto-oncogene. Studied in only a limited number of publications to date, PBF is emerging as a protein with a growing repertoire of roles. Recent data suggest that PBF possesses a complex multifunctionality in an increasing number of tumour settings. For example, PBF is upregulated by oestrogen and mediates oestrogen-stimulated cell invasion in breast cancer cells. In addition to a possible role in the induction of thyroid tumourigenesis, PBF overexpression in thyroid cancers inhibits iodide uptake. PBF has been shown to repress sodium iodide symporter (NIS) activity by transcriptional regulation of NIS expression through the human NIS upstream enhancer and further inhibits iodide uptake via a post-translational mechanism of NIS governing subcellular localisation. This review discusses the current data describing PBF expression and function in thyroid cancer and highlights PBF as a novel target for improving radioiodine uptake and thus prognosis in thyroid cancer.
The ability of trypanosomes to invade the brain and induce an inflammatory reaction is well-recognized. This study uses magnetic resonance imaging (MRI) in conjunction with a murine model of central nervous system (CNS) stage trypanosomiasis to investigate this phenomenon at the level of the blood-brain barrier (BBB). Mice were scanned before and after administration of the contrast agent. Signal enhancement maps were generated, and the percentage signal change was calculated. The severity of the neuroinflammation was also assessed. Statistical analysis of the signal change data revealed a significantly (P = 0.028) higher signal enhancement in mice at 28 days post-infection (least squares mean = 26.709) compared with uninfected animals (6.298), indicating the presence of BBB impairment. Leukocytes were found in the meninges and perivascular space of some blood vessels in the infected mice. This study shows that the integrity of the BBB is compromised during CNS stage trypanosomiasis and that the impairment does not correlate with inflammatory cell infiltration.
The pituitary tumor-transforming gene (PTTG1) encodes a multifunctional protein (PTTG) that is overexpressed in numerous tumours, including pituitary, thyroid, breast and ovarian carcinomas. PTTG induces cellular transformation in vitro and tumourigenesis in vivo, and several mechanisms by which PTTG contributes to tumourigenesis have been investigated. Also known as the human securin, PTTG is involved in cell cycle regulation, controlling the segregation of sister chromatids during mitosis. This review outlines current information regarding PTTG structure, expression, regulation and function in the pathogenesis of neoplasia. Recent progress concerning the use of PTTG as a prognostic marker or therapeutic target will be considered. In addition, the PTTG binding factor (PBF), identified through its interaction with PTTG, has also been established as a proto-oncogene that is upregulated in several cancers. Current knowledge regarding PBF is outlined and its role both independently and alongside PTTG in endocrine and related cancers is discussed.
In non-malignant RWPE-1 prostate epithelial cells signaling by the nuclear receptor Vitamin D Receptor (VDR, NR1I1) induces cell cycle arrest through targets including CDKN1A (encodes p21((waf1/cip1))). VDR dynamically induced individual histone modification patterns at three VDR binding sites (R1, 2, 3) on the CDKN1A promoter. The magnitude of these modifications was specific to each phase of the cell cycle. For example, H3K9ac enrichment occurred rapidly only at R2, whereas parallel accumulation of H3K27me3 occurred at R1; these events were significantly enriched in G(1) and S phase cells, respectively. The epigenetic events appeared to allow VDR actions to combine with p53 to enhance p21((waf1/cip1)) activation further. In parallel, VDR binding to the MCM7 gene induced H3K9ac enrichment associated with rapid mRNA up-regulation to generate miR-106b and consequently regulate p21((waf1/cip1)) expression. We conclude that VDR binding site- and promoter-specific patterns of histone modifications combine with miRNA co-regulation to form a VDR-regulated feed-forward loop to control p21((waf1/cip1)) expression and cell cycle arrest. Dissection of this feed-forward loop in a non-malignant prostate cell system illuminates mechanisms of sensitivity and therefore possible resistance in prostate and other VDR responsive cancers.
Orphan Drug legislation in the USA, Europe and elsewhere has been incredibly successful in promoting the development of new treatments for rare diseases. Historically, payers have constructed special schemes that have facilitated patient access given the small total budget impact of these treatments. However, whilst each disease is rare, the number of licensed orphan drugs is growing rapidly. This, in conjunction with the high prices claimed for these treatments, has increased the total budget impact of orphan drugs. In the medium term, the feasibility of omitting orphan drugs from value for money type assessments is doubtful. The arguments for a special status for orphan drugs in reimbursement processes are reviewed in this article, and it is concluded that these arguments do not generally stand up to critical assessment. A new paradigm for the development and purchase of orphan drugs may be required. Given the strong parallels between the challenges of neglected diseases in developing countries and orphan diseases in developed countries, policy tools developed for neglected diseases; such as Public Private Partnerships and Advance Market Commitments, might be fruitfully applied in the orphan drug arena.
The purpose of this paper is to provide information about cost-effectiveness analysis and the roles of clinical pharmacologists generally in providing efficient health care. The paper highlights the potential consequences of off-label prescribing and indication creep behaviour given slower growth (or potential cuts) in the NHS budget. This paper highlights the key roles of clinical pharmacologists in delivering an efficient health care system when resources are allocated using cost-effectiveness analyses. It describes what cost-effectiveness analysis (CEA) is and how incremental cost-effectiveness ratios (ICERs) are used to identify efficient options. After outlining the theoretical framework within which using CEA can promote the efficient allocation of the health care budget, it considers the place of disinvestment within achieving efficient resource allocation. Clinical pharmacologists are argued to be critical to providing improved population health under CEA-based resource allocation processes because of their roles in implementation and disinvestment. Given that the challenges facing the United Kingdom National Health Service (NHS) are likely to increase, this paper sets out the stark choices facing clinical pharmacologists.
We describe the first clinical application of transient hyperoxia ("oxygen challenge") during T2*-weighted magnetic resonance imaging (MRI), to detect differences in vascular deoxyhemoglobin between tissue compartments following stroke.
In order to decide whether a new treatment should be used in patients, a robust estimate of efficacy and toxicity is no longer sufficient. As a result of increasing healthcare costs across the globe healthcare payers and providers now seek estimates of cost-effectiveness as well. Most trials currently being designed still only consider the need for prospective efficacy and toxicity data during the development life-cycle of a new intervention. Hence the cost-effectiveness estimates are inevitably less precise than the clinical data on which they are based. Methods based on decision theory are being developed by health economists that can contribute to the design of clinical trials in such a way that they can more effectively lead to better informed drug funding decisions on the basis of cost-effectiveness in addition to clinical outcomes. There is an opportunity to apply these techniques prospectively in the design of future clinical trials. This article describes the problems encountered by those responsible for drug reimbursement decisions as a consequence of the current drug development pathway. The potential for decision theoretic methods to help overcome these problems is introduced and potential obstacles in implementation are highlighted.
The loss of anti-proliferative responsiveness in prostate cancer cell lines toward ligands for vitamin D receptor, retinoic acid receptors/retinoid X receptors and peroxisome proliferator activated receptor (PPAR)alpha/gamma may entail underlying epigenetic events, as ligand insensitivity reflects significantly altered messenger RNA expression of corepressors and histone-modifying enzymes. Expression patterns were dependent on phases of the cell cycle and associated with repressed basal gene expression of vitamin D receptor and PPARalpha/gamma target genes, for example CDKN1A [encodes p21((waf1/cip1))]. Elevated nuclear corepressor 1 (NCOR1) and nuclear corepressor 2/silencing mediator of retinoic acid and thyroid hormone receptor protein levels were detected in prostate cancer cell lines compared with non-malignant counterparts. Knockdown of the corepressor NCOR1 significantly elevated basal expression of a cohort of target genes, including CDKN1A. Both chemical [histone deacetylases inhibitor (HDACi)] and NCOR1 knockdown targeting enhanced anti-proliferative sensitivity toward PPARalpha/gamma ligands in prostate cancer cell lines. Pursuing PPARalpha/gamma signaling, microarray approaches were undertaken to identify pathways and genes regulated uniquely by a combination of PPARalpha/gamma activation and HDAC inhibition. Again, HDACi and knockdown approaches demonstrated that elevated NCOR1 expression and activity distorted PPARalpha/gamma gene targets centered on, for example cell cycle control, including CDKN1A and TGFBRAP1. Quantitative real time polymerase chain reaction validation and chromatin immunoprecipitation assays both confirmed that elevated NCOR1 disrupted the ability of PPARalpha/gamma to regulate key target genes (CDKN1A and TGFBRAP1). Interrogation of these relationships in prostate cancer samples using principal component and partial correlation analyses established significant interdependent relationships between NCOR1-PPARalpha/gamma and representative target genes, independently of androgen receptor expression. Therefore, we conclude that elevated NCOR1 distorts the actions of PPARalpha/gamma selectively and generates a potential epigenetic lesion with diagnostic and prognostic significance.
Pituitary tumor transforming gene (PTTG) binding factor (PBF; PTTG1IP) is a relatively uncharacterized oncoprotein whose function remains obscure. Because of the presence of putative estrogen response elements (ERE) in its promoter, we assessed PBF regulation by estrogen. PBF mRNA and protein expression were induced by both diethylstilbestrol and 17beta-estradiol in estrogen receptor alpha (ERalpha)-positive MCF-7 cells. Detailed analysis of the PBF promoter showed that the region -399 to -291 relative to the translational start site contains variable repeats of an 18-bp sequence housing a putative ERE half-site (gcccctcGGTCAcgcctc). Sequencing the PBF promoter from 122 normal subjects revealed that subjects may be homozygous or heterozygous for between 1 and 6 repeats of the ERE. Chromatin immunoprecipitation and oligonucleotide pull-down assays revealed ERalpha binding to the PBF promoter. PBF expression was low or absent in normal breast tissue but was highly expressed in breast cancers. Subjects with greater numbers of ERE repeats showed higher PBF mRNA expression, and PBF protein expression positively correlated with ERalpha status. Cell invasion assays revealed that PBF induces invasion through Matrigel, an action that could be abrogated both by siRNA treatment and specific mutation. Furthermore, PBF is a secreted protein, and loss of secretion prevents PBF inducing cell invasion. Given that PBF is a potent transforming gene, we propose that estrogen treatment in postmenopausal women may upregulate PBF expression, leading to PBF secretion and increased cell invasion. Furthermore, the number of ERE half-sites in the PBF promoter may significantly alter the response to estrogen treatment in individual subjects.
Downs syndrome (DS) is a genetic disorder caused by full or partial trisomy of human chromosome 21 and presents with many clinical phenotypes including a reduced incidence of solid tumours. Recent work with the Ts65Dn model of DS, which has orthologues of about 50% of the genes on chromosome 21 (Hsa21), has indicated that three copies of the ETS2 (ref. 3) or DS candidate region 1 (DSCR1) genes (a previously known suppressor of angiogenesis) is sufficient to inhibit tumour growth. Here we use the Tc1 transchromosomic mouse model of DS to dissect the contribution of extra copies of genes on Hsa21 to tumour angiogenesis. This mouse expresses roughly 81% of Hsa21 genes but not the human DSCR1 region. We transplanted B16F0 and Lewis lung carcinoma tumour cells into Tc1 mice and showed that growth of these tumours was substantially reduced compared with wild-type littermate controls. Furthermore, tumour angiogenesis was significantly repressed in Tc1 mice. In particular, in vitro and in vivo angiogenic responses to vascular endothelial growth factor (VEGF) were inhibited. Examination of the genes on the segment of Hsa21 in Tc1 mice identified putative anti-angiogenic genes (ADAMTS1and ERG) and novel endothelial cell-specific genes, never previously shown to be involved in angiogenesis (JAM-B and PTTG1IP), that, when overexpressed, are responsible for inhibiting angiogenic responses to VEGF. Three copies of these genes within the stromal compartment reduced tumour angiogenesis, explaining the reduced tumour growth in DS. Furthermore, we expect that, in addition to the candidate genes that we show to be involved in the repression of angiogenesis, the Tc1 mouse model of DS will permit the identification of other endothelium-specific anti-angiogenic targets relevant to a broad spectrum of cancer patients.
There is an inevitable tension between robust reimbursement processes and providing speedy access to new and novel technologies, given uncertainties about key pieces of evidence and subsequent concerns regarding their overall efficiency. The public perception of these treatments as breakthrough, combined with substantial clinical pressure, has led to healthcare payers looking for schemes that allow the new technology to be made available to (some) patients, while (at least partially) protecting the principles of their reimbursement decision-making processes. Current literature on these schemes is almost completely descriptive and provides little help in planning future schemes. We propose a framework for evaluating current schemes and informing the design of future schemes. We examine the value of the framework using the UK Multiple Sclerosis Risk-Sharing Scheme as a case study.
As tensions between payers, responsible for ensuring prudent and principled use of scarce resources, and both providers and patients, who legitimately want access to technologies from which they could benefit, continue to mount, interest in approaches to managing the uncertainty surrounding the introduction of new health technologies has heightened. The purpose of this project was to compile an inventory of various types of access with evidence development (AED) schemes, examining characteristics of the technologies to which they have been applied, the uncertainty they sought to address, the terms of arrangements of each scheme, and the policy outcomes. It also aimed to identify issues related to such schemes, including advantages and disadvantages from the perspectives of various stakeholder groups. A comprehensive search, review and appraisal of peer-reviewed and grey literature were performed, followed by a facilitated workshop of academics and decision makers with expertise in AED schemes. Information was extracted and compiled in tabular form to identify patterns or trends. To enhance the validity of interpretations made, member checking was performed. Although the concept of AED is not new, evaluative data are sparse. Despite varying opinions on the right answers to some of the questions raised, there appears to be consensus on a way forward--development of methodological guidelines. All stakeholders seemed to share the view that AEDs offer the potential to facilitate patient access to promising new technologies and encourage innovation while ensuring effective use of scarce healthcare resources. There is no agreement on what constitutes sufficient evidence, and it depends on the specific uncertainty in question. There is agreement on the need for best practice guidelines around the implementation and evaluation of AED schemes. This is the first attempt at a comprehensive analysis of methods that have been used to address uncertainty concerning a new drug or other technology. The analysis reveals that, although various approaches have been experimented with, many of them have not achieved the ostensible goal of the approach. This article outlines challenges related to AED schemes and issues that remain unresolved.
Context: After brain stem death (BSD), a low T(3) state is common, and T(3) supplementation has been advocated to improve heart function and yield for transplantation. Objectives: The aim of the study was to assess the effects of T(3) on expression of mRNAs encoding T(3)-responsive genes in the post-BSD human heart. Design: Within a prospective double-blind trial, potential BSD cardiac donors undergoing hemodynamic optimization were randomized to T(3) (0.8 microg . kg(-1) bolus; infusion 0.113 microg . kg(-1) . h(-1)) or placebo (5% dextrose) for up to 6 h. Left ventricular biopsies were obtained at end-assessment from 30 donors (T(3); n=16). TaqMan real-time PCR was performed to investigate mRNA expression of the voltage-gated potassium channel Kv1.5, beta-1 adrenergic receptor (ADRB1), sarcoplasmic reticulum calcium ATPase type 2a (SERCA2a), and phospholamban (PLB). Results: Time between diagnosis of BSD and donor management was 13.2 h (range, 9.7-16.8 h). T(3) donors were managed for 7.6 (6.9-8.3) h. Median serum free T(3) (fT3) at baseline was 2.9 (2.3-3.8) pmol . liter(-1) (reference range, 3.3-7.5 pmol . liter(-1)). At baseline, 19 of 30 (56.7%) had low serum fT3, and T(3) treatment increased fT3 to supraphysiological levels (P < 0.001). Expression of mRNAs encoding Kv1.5 and SERCA2a was increased 1.99-fold and 1.51-fold (P = 0.015 and 0.043). There was no significant change in the expression of mRNAs encoding ADRB1 and PLB. Treatment with T(3) did not improve hemodynamic function compared with placebo. Conclusions: Acute administration of T(3) in the BSD cardiac donor reverses the low T(3) state and increases expression of the mRNAs encoding Kv1.5 and SERCA2a, but not ADRB1 or PLB and is not associated with any improvement in hemodynamic performance.
N-terminal pro-B-type natriuretic peptide (NT-proBNP) is elevated in subarachnoid haemorrhage, brainstem death (BSD) and heart failure. We examined the relationship between NT-proBNP and cardiac functional status after BSD and left ventricular (LV) BNP precursor gene expression.
Current practice in economic evaluation is to assign equal social value to a unit of health improvement (a QALY is a QALY is a QALY). Alternative equity positions are typically considered separately from efficiency. One proposal seeks to integrate these two sets of societal concerns by attaching equity weights to QALYs. To date, research in pursuit of this goal has focussed on candidate equity criteria and methods for estimating such weights. It has implicitly been assumed that should legitimate, valid and reliable equity weights become available, it would be a straightforward task to incorporate them as a separate simple calculation after estimating cost per un-weighted QALY. This article suggests that, in many situations, these simple approaches to incorporating equity weights will not appropriately reflect the preferences on which the weights are based and that the appropriate incorporation of equity weights in cost-effectiveness analyses will be technically challenging. In addition to the technical challenges, there are a number of issues that arise in the movement from implicit to explicit consideration of equity. Whilst equity weights can, conceptually, be incorporated in economic evaluation, there are a number of challenges to be addressed before the results of such analyses can be considered robust and a fit basis for resource allocation decisions.
Stroke-prone spontaneously hypertensive rats (SHRSP) are a highly pertinent stroke model with increased sensitivity to focal ischemia compared with the normotensive reference strain (Wistar-Kyoto rats; WKY). Study aims were to investigate temporal changes in the ischemic penumbra in SHRSP compared with WKY.
Differentiated thyroid cancers and their metastases frequently exhibit reduced iodide uptake, impacting on the efficacy of radioiodine ablation therapy. PTTG binding factor (PBF) is a proto-oncogene implicated in the pathogenesis of thyroid cancer. We recently reported that PBF inhibits iodide uptake, and have now elucidated a mechanism by which PBF directly modulates sodium iodide symporter (NIS) activity in vitro. In subcellular localisation studies, PBF overexpression resulted in the redistribution of NIS from the plasma membrane into intracellular vesicles, where it colocalised with the tetraspanin CD63. Cell-surface biotinylation assays confirmed a reduction in plasma membrane NIS expression following PBF transfection compared with vector-only treatment. Coimmunoprecipitation and GST-pull-down experiments demonstrated a direct interaction between NIS and PBF, the functional consequence of which was assessed using iodide-uptake studies in rat thyroid FRTL-5 cells. PBF repressed iodide uptake, whereas three deletion mutants, which did not localise within intracellular vesicles, lost the ability to inhibit NIS activity. In summary, we present an entirely novel mechanism by which the proto-oncogene PBF binds NIS and alters its subcellular localisation, thereby regulating its ability to uptake iodide. Given that PBF is overexpressed in thyroid cancer, these findings have profound implications for thyroid cancer ablation using radioiodine.
Magnetic resonance imaging (MRI) has evolved as one of the major non-invasive tools to study healthy and diseased hearts in animal models, especially rodent models. Even though, the chick embryo has long been used as a model for cardiovascular research, MRI has not yet been used for in vivo cardiac studies. Part of the reason for this is the difficulty in monitoring the ECG and respiration of the chick embryo in the magnet for gating purposes. To overcome this complication, this paper presents the use of retrospective Cine MRI to measure the cardiac function of chick embryos in ovo for the first time, without the need for respiratory or cardiac gating. The resulting left ventricular functional parameters, from six chick embryos at 20 days of incubation, were (mean +/- SD) EDV 69 +/- 15 microL, ESV 31 +/- 7 microL, SV 38 +/- 9 microL and EF 54.5 +/- 2%. The use of retrospective Cine MRI at earlier stages of development is also discussed and difficulties have been highlighted.
Graves disease (GD) is a common autoimmune disease (AID) that shares many of its susceptibility loci with other AIDs. The thyroid stimulating hormone receptor (TSHR) represents the primary autoantigen in GD, in which autoantibodies bind to the receptor and mimic its ligand, thyroid stimulating hormone, causing the characteristic clinical phenotype. Although early studies investigating the TSHR and GD proved inconclusive, more recently we provided convincing evidence for association of the TSHR region with disease. In the current study, we investigated a combined panel of 98 SNPs, including 70 tag SNPs, across an extended 800 kb region of the TSHR to refine association in a cohort of 768 GD subjects and 768 matched controls. In total, 28 SNPs revealed association with GD (P < 0.05), with strongest SNP associations at rs179247 (chi(2) = 32.45, P = 8.90 x 10(-8), OR = 1.53, 95% CI = 1.32-1.78) and rs12101255 (chi(2) = 30.91, P = 1.95 x 10(-7), OR = 1.55, 95% CI = 1.33-1.81), both located in intron 1 of the TSHR. Association of the most associated SNP, rs179247, was replicated in 303 GD families (P = 7.8 x 10(-4)). In addition, we provide preliminary evidence that the disease-associated genotypes of rs179247 (AA) and rs12101255 (TT) show reduced mRNA expression ratios of flTSHR relative to two alternate TSHR mRNA splice variants.
The current study investigated transcriptional distortion in prostate cancer cells using the vitamin D receptor (VDR) as a tool to examine how epigenetic events driven by corepressor binding and CpG methylation lead to aberrant gene expression. These relationships were investigated in the non-malignant RWPE-1 cells that were 1?,25(OH)(2)D(3) responsive (RWPE-1) and malignant cell lines that were 1?,25(OH)(2)D(3) partially responsive (RWPE-2) and resistant (PC-3). These studies revealed that selective attenuation and repression of VDR transcriptional responses in the cancer cell lines reflected their loss of antiproliferative sensitivity. This was evident in VDR target genes including VDR, CDKN1A (encodes p21( (waf1/cip1) )) and GADD45A; NCOR1 knockdown alleviated this malignant transrepression. ChIP assays in RWPE-1 and PC-3 cells revealed that transrepression of CDKN1A was associated with increased NCOR1 enrichment in response to 1?,25(OH)(2)D(3) treatment. These findings supported the concept that retained and increased NCOR1 binding, associated with loss of H3K9ac and increased H3K9me2, may act as a beacon for the initiation and recruitment of DNA methylation. Overexpressed histone methyltransferases (KMTs) were detectable in a wide panel of prostate cancer cell lines compared with RWPE-1 and suggested that generation of H3K9me2 states would be favored. Cotreatment of cells with the KMT inhibitor, chaetocin, increased 1?,25(OH)(2)D(3)-mediated induction of CDKN1A expression supporting a role for this event to disrupt CDKN1A regulation. Parallel surveys in PC-3 cells of CpG methylation around the VDR binding regions on CDKN1A revealed altered basal and VDR-regulated DNA methylation patterns that overlapped with VDR-induced recruitment of NCOR1 and gene transrepression. Taken together, these findings suggest that sustained corepressor interactions with nuclear-resident transcription factors may inappropriately transform transient-repressive histone states into more stable and repressive DNA methylation events.
We describe a positive influence of pre-stroke surgery on recovery and survival in a commonly used experimental stroke model. Two groups of male, stroke-prone spontaneously hypertensive rats (SHRSPs) underwent transient middle cerebral artery occlusion (tMCAO). Group 1 underwent the procedure without any prior intervention whilst group 2 had an additional general anaesthetic 6 days prior to tMCAO for a cranial burrhole and durotomy. Post-stroke recovery was assessed using a 32 point neurological deficit score and tapered beam walk and infarct volume determined from haematoxylin-eosin stained sections. In group 2 survival was 92% (n=12) versus 67% in group 1 (n=18). In addition, post-tMCAO associated weight loss was significantly reduced in group 2. There was no significant difference between the two groups in experimental outcomes: infarct volume (Group 1 317±18.6 mm³ versus Group 2 332±20.4 mm³), and serial (day 0-14 post-tMCAO) neurological deficit scores and tapered-beam walk test. Drilling a cranial burrhole under general anaesthesia prior to tMCAO in SHRSP reduced mortality and gave rise to infarct volumes and neurological deficits similar to those recorded in surviving Group 1 animals. This methodological refinement has significant implications for animal welfare and group sizes required for intervention studies.
Perfusion-diffusion (perfusion-weighted imaging (PWI)/diffusion-weighted imaging (DWI)) mismatch is used to identify penumbra in acute stroke. However, limitations in penumbra detection with mismatch are recognized, with a lack of consensus on thresholds, quantification and validation of mismatch. We determined perfusion and diffusion thresholds from final infarct in the clinically relevant spontaneously hypertensive stroke-prone (SHRSP) rat and its normotensive control strain, Wistar-Kyoto (WKY) and compared three methods for penumbra calculation. After permanent middle cerebral artery occlusion (MCAO) (WKY n=12, SHRSP n=15), diffusion-weighted (DWI) and perfusion-weighted (PWI) images were obtained for 4 hours post stroke and final infarct determined at 24 hours on T(2) scans. The PWI/DWI mismatch was calculated from volumetric assessment (perfusion deficit volume minus apparent diffusion coefficient (ADC)-defined lesion volume) or spatial assessment of mismatch area on each coronal slice. The ADC-derived lesion growth provided the third, retrospective measure of penumbra. At 1 hour after MCAO, volumetric mismatch detected smaller volumes of penumbra in both strains (SHRSP: 31 ± 50 mm(3), WKY: 22 ± 59 mm(3), mean ± s.d.) compared with spatial assessment (SHRSP: 36 ± 15 mm(3), WKY: 43 ± 43 mm(3)) and ADC lesion expansion (SHRSP: 41 ± 45 mm(3), WKY: 65 ± 41 mm(3)), although these differences were not statistically significant. Spatial assessment appears most informative, using both diffusion and perfusion data, eliminating the influence of negative mismatch and allowing the anatomical location of penumbra to be assessed at given time points after stroke.
Tandem mass spectrometry (MS/MS) permits the detection of femtomolar quantities of protein from a wide variety of tissue sources. As endocrine cancers are frequently aetiologically complex, they are particularly amenable to mass spectrometry. The most widely studied aspect is the search for novel reliable biomarkers that would allow cancers to be diagnosed earlier and distinguished from benign tumours. MS/MS allows for the rapid analysis of blood and urine in addition to tumour tissue, and in this regard it has been applied on research involving thyroid, pancreatic, adrenal and ovarian cancers with varying degrees of success, as well as additional organ sites including breast and lung. The description of an individual cancer proteome potentially allows for personalized management of each patient, avoiding unnecessary therapies and targeting treatments to those which will have the most effect. The application of MS/MS to interaction proteomics is a field that has generated recent novel targets for chemotherapy. However, the technology involved in MS/MS has a number of drawbacks that at present prevent its widespread use in translational cancer research, including a poor reproducibility of results, in part due to the large amount of data generated and the inability to accurately differentiate true from false-positive results. Further, the current cost of running MS/MS restricts the number of times the experiments can be repeated, contributing to the lack of significance and concordance between studies. Despite these problems, however, MS/MS is emerging as a front line tool in endocrine cancer research and it is likely that this will continue over the next decade.
The Expected Value of Information Framework has been proposed as a method for identifying when health care technologies should be immediately reimbursed and when any reimbursement should be withheld while awaiting more evidence. This framework assesses the value of obtaining additional evidence to inform a current reimbursement decision. This represents the burden of not having the additional evidence at the time of the decision. However, when deciding whether to reimburse now or await more evidence, decision makers need to know the value of investing in more research to inform a future decision. Assessing this value requires consideration of research costs, research time, and what happens to patients while the research is undertaken and after completion. The investigators describe a development of the calculation of the expected value of sample information that assesses the value of investing in further research, including an only-in-research strategy and an only-with-research strategy.
Arterial spin labelling (ASL) is increasingly available for noninvasive cerebral blood flow (CBF) measurement in stroke research. Here, a pseudo-continuous ASL technique (pCASL) was evaluated against (99m)Tc-D, L-hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) autoradiography in a rat stroke model. The (99m)Tc-HMPAO was injected (intravenously, 225?MBq) during pCASL acquisition. The pCASL and (99m)Tc-HMPAO autoradiography CBF measures, relative to the contralateral hemisphere, were in good agreement across the spectrum of flow values in normal and ischemic tissues. The pCASL-derived quantitative regional CBF values (contralateral: 157 to 177?mL/100?g per minute; ipsilateral: 9 to 104?mL/100?g per minute) were consistent with the literature values. The data show the potential utility of pCASL for CBF assessment in a rat stroke model.
The importance of the thyroid hormone (TH) transporter, monocarboxylate transporter (MCT8), to human neurodevelopment is highlighted by findings of severe global neurological impairment in subjects with MCT8 mutations. Intrauterine growth restriction (IUGR), usually due to uteroplacental failure, is associated with milder neurodevelopmental deficits, which have been partly attributed to dysregulated TH action in utero secondary to reduced circulating fetal TH concentrations and decreased cerebral TH receptor expression. We postulate that altered MCT8 expression is implicated in this pathophysiology and sought to quantify changes in cortical MCT8 expression with IUGR. Firstly, MCT8 immunohistochemistry was performed on occipital and parietal cerebral cortex sections from appropriately grown for gestational age (AGA) human fetuses between 19 weeks gestation and term. Secondly, MCT8 immunostaining in the occipital cortex of stillborn IUGR human fetuses at 24-28 weeks gestation were objectively compared with gestationally-matched AGA fetuses. Fetuses demonstrated widespread MCT8 expression in neurons within the cortical plate and subplate, in the ventricular and subventricular zones, epithelium of the choroid plexus and ependyma, and microvessel wall. When complicated by IUGR, fetuses showed a significant 5-fold reduction in the percentage area of cortical plate immunostained with MCT8 compared with AGA fetuses (p<0.05) but there was no significant difference in the proportion of subplate microvessels immunostained. Cortical MCT8 expression negatively correlated with the severity of IUGR indicated by brain:liver weight ratios (r2=0.28, p<0.05) at post-mortem. Our results support the hypothesis that a reduction in MCT8 expression in the IUGR fetal brain could further compromise TH-dependent brain development.
Related JoVE Video
Journal of Visualized Experiments
What is Visualize?
JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.
How does it work?
We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.
Video X seems to be unrelated to Abstract Y...
In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.