JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Cerebral metabolite changes prior to and after antiretroviral therapy in primary HIV infection.
Neurology
PUBLISHED: 09-26-2014
Show Abstract
Hide Abstract
We examined the longitudinal effects of primary HIV infection (PHI) and responses to early antiretroviral therapy (ART) on the brain using high-field magnetic resonance spectroscopy (MRS).
Related JoVE Video
CD4 trajectory adjusting for dropout among HIV-positive patients receiving combination antiretroviral therapy in an East African HIV care centre.
J Int AIDS Soc
PUBLISHED: 08-14-2014
Show Abstract
Hide Abstract
Estimates of CD4 response to antiretroviral therapy (ART) obtained by averaging data from patients in care, overestimate population CD4 response and treatment program effectiveness because they do not consider data from patients who are deceased or not in care. We use mathematical methods to assess and adjust for this bias based on patient characteristics.
Related JoVE Video
Observational research on NCDs in HIV-positive populations: conceptual and methodological considerations.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 08-14-2014
Show Abstract
Hide Abstract
Noncommunicable diseases (NCDs) account for a growing burden of morbidity and mortality among people living with HIV in low- and middle-income countries (LMICs). HIV infection and antiretroviral therapy interact with NCD risk factors in complex ways, and research into this "web of causation" has so far been largely based on data from high-income countries. However, improving the understanding, treatment, and prevention of NCDs in LMICs requires region-specific evidence. Priority research areas include: (1) defining the burden of NCDs among people living with HIV, (2) understanding the impact of modifiable risk factors, (3) evaluating effective and efficient care strategies at individual and health systems levels, and (4) evaluating cost-effective prevention strategies. Meeting these needs will require observational data, both to inform the design of randomized trials and to replace trials that would be unethical or infeasible. Focusing on Sub-Saharan Africa, we discuss data resources currently available to inform this effort and consider key limitations and methodological challenges. Existing data resources often lack population-based samples; HIV-negative, HIV-positive, and antiretroviral therapy-naive comparison groups; and measurements of key NCD risk factors and outcomes. Other challenges include loss to follow-up, competing risk of death, incomplete outcome ascertainment and measurement of factors affecting clinical decision making, and the need to control for (time-dependent) confounding. We review these challenges and discuss strategies for overcoming them through augmented data collection and appropriate analysis. We conclude with recommendations to improve the quality of data and analyses available to inform the response to HIV and NCD comorbidity in LMICs.
Related JoVE Video
Delayed switch of antiretroviral therapy after virologic failure associated with elevated mortality among HIV-infected adults in Africa.
AIDS
PUBLISHED: 07-01-2014
Show Abstract
Hide Abstract
Routine monitoring of plasma HIV RNA among HIV-infected patients on antiretroviral therapy (ART) is unavailable in many resource-limited settings. Alternative monitoring approaches correlate poorly with virologic failure and can substantially delay switch to second-line therapy. We evaluated the impact of delayed switch on mortality among patients with virologic failure in Africa.
Related JoVE Video
Phase II design with sequential testing of hypotheses within each stage.
J Biopharm Stat
PUBLISHED: 04-05-2014
Show Abstract
Hide Abstract
The main goal of a Phase II clinical trial is to decide, whether a particular therapeutic regimen is effective enough to warrant further study. The hypothesis tested by Fleming's Phase II design (Fleming, 1982) is [Formula: see text] versus [Formula: see text], with level [Formula: see text] and with a power [Formula: see text] at [Formula: see text], where [Formula: see text] is chosen to represent the response probability achievable with standard treatment and [Formula: see text] is chosen such that the difference [Formula: see text] represents a targeted improvement with the new treatment. This hypothesis creates a misinterpretation mainly among clinicians that rejection of the null hypothesis is tantamount to accepting the alternative, and vice versa. As mentioned by Storer (1992), this introduces ambiguity in the evaluation of type I and II errors and the choice of the appropriate decision at the end of the study. Instead of testing this hypothesis, an alternative class of designs is proposed in which two hypotheses are tested sequentially. The hypothesis [Formula: see text] versus [Formula: see text] is tested first. If this null hypothesis is rejected, the hypothesis [Formula: see text] versus [Formula: see text] is tested next, in order to examine whether the therapy is effective enough to consider further testing in a Phase III study. For the derivation of the proposed design the exact binomial distribution is used to calculate the decision cut-points. The optimal design parameters are chosen, so as to minimize the average sample number (ASN) under specific upper bounds for error levels. The optimal values for the design were found using a simulated annealing method.
Related JoVE Video
Choosing profile double-sampling designs for survival estimation with application to President's Emergency Plan for AIDS Relief evaluation.
Stat Med
PUBLISHED: 01-10-2014
Show Abstract
Hide Abstract
Most studies that follow subjects over time are challenged by having some subjects who dropout. Double sampling is a design that selects and devotes resources to intensively pursue and find a subset of these dropouts, then uses data obtained from these to adjust naïve estimates, which are potentially biased by the dropout. Existing methods to estimate survival from double sampling assume a random sample. In limited-resource settings, however, generating accurate estimates using a minimum of resources is important. We propose using double-sampling designs that oversample certain profiles of dropouts as more efficient alternatives to random designs. First, we develop a framework to estimate the survival function under these profile double-sampling designs. We then derive the precision of these designs as a function of the rule for selecting different profiles, in order to identify more efficient designs. We illustrate using data from the United States President's Emergency Plan for AIDS Relief-funded HIV care and treatment program in western Kenya. Our results show why and how more efficient designs should oversample patients with shorter dropout times. Further, our work suggests generalizable practice for more efficient double-sampling designs, which can help maximize efficiency in resource-limited settings.
Related JoVE Video
Longitudinal characterization of depression and mood states beginning in primary HIV infection.
AIDS Behav
PUBLISHED: 01-04-2014
Show Abstract
Hide Abstract
Though depression is known to frequently afflict those with chronic HIV, mood during the early course of HIV is not well characterized. In a prospective study we assessed mood during primary HIV infection [primary HIV infection (PHI), <1 year duration], its association with neuropsychological performance and markers of neurological disease, and its longitudinal course including effects of antiretroviral therapy (ART). The Beck Depression Inventory (BDI) and Profile of Mood States (POMS) subscales were longitudinally administered prior to and after ART in PHI subjects. This evaluation of mood was done concurrently with blood, cerebrospinal fluid (CSF) and neuropsychological [total z and global deficit score (GDS)] evaluation at each visit. Analysis employed Spearman's rho, logistic regression, and linear mixed models. 47.7 % of the 65 men recruited at a median 3.5 months HIV duration met BDI criteria for clinical depression at baseline, classified as 'mild' (n = 11), 'moderate' (n = 11), or 'severe' (n = 9). Drug, alcohol, and depression history did not associate with BDI score. Proportional somatic-performance scores were worse than cognitive-affective scores (p = .0045). Vigor subscore of POMS was reduced compared to norms and correlated with total z (r = 0.33, p = 0.013) and GDS (r = -0.32, p = 0.016). BDI and POMS correlated with one another (r = 0.85, p < .0001), but not with CSF or plasma HIV RNA, WBC, albumin ratio or neopterin. Improvement was not observed in BDI and POMS over 330 total follow-up visits, even after initiation of ART. Depression was prevalent during PHI in our subjects, associated with abnormal somatic-performance and vigor scores. Neither neuropsychological performance nor disease biomarkers correlated with depressed mood. Mood indices did not improve over time in the presence of ART.
Related JoVE Video
Neurovirological correlation with HIV-associated neurocognitive disorders and encephalitis in a HAART-era cohort.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 10-19-2013
Show Abstract
Hide Abstract
Replicating HIV-1 in the brain is present in HIV encephalitis (HIVE) and microglial nodule encephalitis (MGNE) and is putatively linked with HIV-associated neurocognitive disorders (HAND). A cliniconeurovirological correlation was conducted to elucidate the relationship between brain viral load and clinical phenotype. SUBJECTS AND ASSAYS: HIV gag/pol RNA and DNA copies were quantified with reverse transcriptase-polymerase chain reaction or polymerase chain reaction in 148 HAART-era brain specimens. Comparison with HAND, HIVE, and MGNE and correlation with neuropsychological (NP) test scores were done using one-way ANOVA with Tukey-Kramer and Spearman tests, respectively.
Related JoVE Video
A multi-index ROC-based methodology for high throughput experiments in gene discovery.
Int J Data Min Bioinform
PUBLISHED: 07-20-2013
Show Abstract
Hide Abstract
We address the problem of ranking differentially expressed genes in high throughput experiments using Receiver Operating Characteristic (ROC) curves. As it is generally unknown whether large expression values constitute positive or negative results or which group is healthy or diseased, we generate four ROC curves per gene. We then consider classification indices based on all or part of the four ROC curves and identify genes ranked low by the area under the curve (AUC) but high by at least one alternative index, invariably resulting to the discovery of genes that would otherwise be missed by the AUC index.
Related JoVE Video
Progressive cerebral injury in the setting of chronic HIV infection and antiretroviral therapy.
J. Neurovirol.
PUBLISHED: 04-01-2013
Show Abstract
Hide Abstract
Emerging evidence suggests that CNS injury and neurocognitive impairment persist in the setting of chronic HIV infection and combination antiretroviral therapy (CART). Yet, whether neurological injury can progress in this setting remains uncertain. Magnetic resonance spectroscopy and neurocognitive and clinical assessments were performed over 2 years in 226 HIV-infected individuals on stable CART, including 138 individuals who were neurocognitively asymptomatic (NA). Concentrations of N-acetylaspartate (NAA), creatine (Cr), choline (Cho), myoinositol, and glutamate/glutamine (Glx) were measured in the midfrontal cortex (MFC), frontal white matter (FWM), and basal ganglia (BG). Longitudinal changes in metabolite levels were determined using linear mixed effect models, as were metabolite changes in relation to global neurocognitive function. HIV-infected subjects showed significant annual decreases in brain metabolite levels in all regions examined, including NAA (2.95 %) and Cho (2.61 %) in the FWM; NAA (1.89 %), Cr (1.84 %), Cho (2.19 %), and Glx (6.05 %) in the MFC; and Glx (2.80 %) in the BG. Similar metabolite decreases were observed in the NA and subclinically impaired subgroups, including subjects with virologic suppression in plasma and CSF. Neurocognitive decline was associated with longitudinal decreases in Glx in the FWM and the BG, and in NAA in the BG. Widespread progressive changes in the brain, including neuronal injury, occur in chronically HIV-infected persons despite stable antiretroviral treatment and virologic suppression and can lead to neurocognitive declines. The basis for these findings is poorly understood and warrants further study.
Related JoVE Video
Failure to Suppress Markers of Bone Turnover on First-Line Hormone Therapy for Metastatic Prostate Cancer Is Associated With Shorter Time to Skeletal-Related Event.
Clin Genitourin Cancer
PUBLISHED: 03-23-2013
Show Abstract
Hide Abstract
Elevated markers of bone turnover are prognostic for shorter survival in castration-resistant prostate cancer. We aimed to determine the prognostic value of bone turnover markers in metastatic hormone-sensitive prostate cancer.
Related JoVE Video
Outcomes of antiretroviral therapy in children in Asia and Africa: a comparative analysis of the IeDEA pediatric multiregional collaboration.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 03-09-2013
Show Abstract
Hide Abstract
We investigated 18-month incidence and determinants of death and loss to follow-up of children after antiretroviral therapy (ART) initiation in a multiregional collaboration in lower-income countries.
Related JoVE Video
Failure to initiate antiretroviral therapy, loss to follow-up and mortality among HIV-infected patients during the pre-ART period in Uganda.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 02-23-2013
Show Abstract
Hide Abstract
Delays and failures in initiation of antiretroviral therapy (ART) among treatment eligible patients may compromise the effectiveness of HIV care in Africa. An accurate understanding, however, of the pace and completeness of ART initiation and mortality during the waiting period is obscured by frequent losses to follow-up.
Related JoVE Video
Cerebrospinal fluid neopterin decay characteristics after initiation of antiretroviral therapy.
J Neuroinflammation
PUBLISHED: 02-04-2013
Show Abstract
Hide Abstract
Neopterin, a biomarker of macrophage activation, is elevated in the cerebrospinal fluid (CSF) of most HIV-infected individuals and decreases after initiation of antiretroviral therapy (ART). We studied decay characteristics of neopterin in CSF and blood after commencement of ART in HIV-infected subjects and estimated the set-point levels of CSF neopterin after ART-mediated viral suppression.
Related JoVE Video
Active tuberculosis is associated with worse clinical outcomes in HIV-infected African patients on antiretroviral therapy.
PLoS ONE
PUBLISHED: 01-02-2013
Show Abstract
Hide Abstract
This cohort study utilized data from a large HIV treatment program in western Kenya to describe the impact of active tuberculosis (TB) on clinical outcomes among African patients on antiretroviral therapy (ART).
Related JoVE Video
Disrupted cerebral metabolite levels and lower nadir CD4 + counts are linked to brain volume deficits in 210 HIV-infected patients on stable treatment.
Neuroimage Clin
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
Cognitive impairment and brain injury are common in people with HIV/AIDS, even when viral replication is effectively suppressed with combined antiretroviral therapies (cART). Metabolic and structural abnormalities may promote cognitive decline, but we know little about how these measures relate in people on stable cART. Here we used tensor-based morphometry (TBM) to reveal the 3D profile of regional brain volume variations in 210 HIV + patients scanned with whole-brain MRI at 1.5 T (mean age: 48.6 ± 8.4 years; all receiving cART). We identified brain regions where the degree of atrophy was related to HIV clinical measures and cerebral metabolite levels assessed with magnetic resonance spectroscopy (MRS). Regional brain volume reduction was linked to lower nadir CD4 + count, with a 1-2% white matter volume reduction for each 25-point reduction in nadir CD4 +. Even so, brain volume measured by TBM showed no detectable association with current CD4 + count, AIDS Dementia Complex (ADC) stage, HIV RNA load in plasma or cerebrospinal fluid (CSF), duration of HIV infection, antiretroviral CNS penetration-effectiveness (CPE) scores, or years on cART, after controlling for demographic factors, and for multiple comparisons. Elevated glutamate and glutamine (Glx) and lower N-acetylaspartate (NAA) in the frontal white matter, basal ganglia, and mid frontal cortex - were associated with lower white matter, putamen and thalamus volumes, and ventricular and CSF space expansion. Reductions in brain volumes in the setting of chronic and stable disease are strongly linked to a history of immunosuppression, suggesting that delays in initiating cART may result in imminent and irreversible brain damage.
Related JoVE Video
Determinants of early and late mortality among HIV-infected individuals receiving home-based antiretroviral therapy in rural Uganda.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 08-23-2011
Show Abstract
Hide Abstract
Up to 20% of people initiating antiretroviral therapy (ART) in sub-Saharan Africa die during the first year of treatment. Understanding the clinical conditions associated with mortality could potentially lead to effective interventions to prevent these deaths.
Related JoVE Video
Alternative antiretroviral monitoring strategies for HIV-infected patients in east Africa: opportunities to save more lives?
J Int AIDS Soc
PUBLISHED: 07-30-2011
Show Abstract
Hide Abstract
Updated World Health Organization guidelines have amplified debate about how resource constraints should impact monitoring strategies for HIV-infected persons on combination antiretroviral therapy (cART). We estimated the incremental benefit and cost effectiveness of alternative monitoring strategies for east Africans with known HIV infection.
Related JoVE Video
Retention in care and connection to care among HIV-infected patients on antiretroviral therapy in Africa: estimation via a sampling-based approach.
PLoS ONE
PUBLISHED: 06-11-2011
Show Abstract
Hide Abstract
Current estimates of retention among HIV-infected patients on antiretroviral therapy (ART) in Africa consider patients who are lost to follow-up (LTF) as well as those who die shortly after their last clinic visit to be no longer in care and to represent limitations in access to care. Yet many lost patients may have "silently" transferred and deaths shortly after the last clinic visit more likely represent limitations in clinical care rather than access to care after initial linkage.
Related JoVE Video
Universal definition of loss to follow-up in HIV treatment programs: a statistical analysis of 111 facilities in Africa, Asia, and Latin America.
PLoS Med.
PUBLISHED: 04-13-2011
Show Abstract
Hide Abstract
Although patient attrition is recognized as a threat to the long-term success of antiretroviral therapy programs worldwide, there is no universal definition for classifying patients as lost to follow-up (LTFU). We analyzed data from health facilities across Africa, Asia, and Latin America to empirically determine a standard LTFU definition.
Related JoVE Video
Survival after resection for invasive intraductal papillary mucinous neoplasm and for pancreatic adenocarcinoma: a multi-institutional comparison according to American Joint Committee on Cancer Stage.
J. Am. Coll. Surg.
PUBLISHED: 04-04-2011
Show Abstract
Hide Abstract
Survival after resection for invasive intraductal papillary mucinous neoplasm (inv-IPMN) is superior to pancreatic ductal adenocarcinoma (PDAC). This difference may be explained by earlier presentation of inv-IPMN. We hypothesized that inv-IPMN has survival comparable with PDAC after resection when matched by stage.
Related JoVE Video
"Wamepotea" (they have become lost): outcomes of HIV-positive and HIV-exposed children lost to follow-up from a large HIV treatment program in western Kenya.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 03-17-2011
Show Abstract
Hide Abstract
The objective of this study was to identify the vital status and reasons for children becoming loss to follow-up (LTFU) from a large program in western Kenya.
Related JoVE Video
Trends in the clinical characteristics of HIV-infected patients initiating antiretroviral therapy in Kenya, Uganda and Tanzania between 2002 and 2009.
J Int AIDS Soc
PUBLISHED: 02-19-2011
Show Abstract
Hide Abstract
East Africa has experienced a rapid expansion in access to antiretroviral therapy (ART) for HIV-infected patients. Regionally representative socio-demographic, laboratory and clinical characteristics of patients accessing ART over time and across sites have not been well described.
Related JoVE Video
Persistence of HIV-associated cognitive impairment, inflammation, and neuronal injury in era of highly active antiretroviral treatment.
AIDS
PUBLISHED: 02-08-2011
Show Abstract
Hide Abstract
To determine whether cognitive impairment and brain injury as measured by proton magnetic resonance spectroscopy (MRS) persist in the setting of HAART.
Related JoVE Video
Quantification of accuracy and precision of multi-center DTI measurements: a diffusion phantom and human brain study.
Neuroimage
PUBLISHED: 01-28-2011
Show Abstract
Hide Abstract
The inter-site and intra-site variability of system performance of MRI scanners (due to site-dependent and time-variant variations) can have significant adverse effects on the integration of multi-center DTI data. Measurement errors in accuracy and precision of each acquisition determine both the inter-site and intra-site variability. In this study, multiple scans of an identical isotropic diffusion phantom and of the brain of a traveling human volunteer were acquired at MRI scanners from the same vendor and with similar configurations at three sites. We assessed the feasibility of multi-center DTI studies by direct quantification of accuracy and precision of each dataset. Accuracy was quantified via comparison to carefully constructed gold standard datasets while precision (the within-scan variability) was estimated by wild bootstrap analysis. The results from both the phantom and human data suggest that the inter-site variation in system performance, although relatively small among scanners of the same vendor, significantly affects DTI measurement accuracy and precision and therefore the effectiveness for the integration of multi-center DTI measurements. Our results also highlight the value of a DTI-specific phantom in identifying and quantifying measurement errors due to site-dependent variations in the system performance, and its usefulness for quality assurance/quality control in multi-center DTI studies. In addition, we observed that the within-scan variability of each data acquisition, as assessed by wild bootstrap analysis, is of the same magnitude as the inter-site and intra-site variability. We propose that by weighing datasets based on their variability, as evaluated by wild bootstrap analysis, one can improve the quality of the dataset. This approach will provide a more effective integration of datasets from multi-center DTI studies.
Related JoVE Video
Chemokines in cerebrospinal fluid correlate with cerebral metabolite patterns in HIV-infected individuals.
J. Neurovirol.
PUBLISHED: 01-19-2011
Show Abstract
Hide Abstract
Chemokines influence HIV neuropathogenesis by affecting the HIV life cycle, trafficking of macrophages into the nervous system, glial activation, and neuronal signaling and repair processes; however, knowledge of their relationship to in vivo measures of cerebral injury is limited. The primary objective of this study was to determine the relationship between a panel of chemokines in cerebrospinal fluid (CSF) and cerebral metabolites measured by proton magnetic resonance spectroscopy (MRS) in a cohort of HIV-infected individuals. One hundred seventy-one stored CSF specimens were assayed from HIV-infected individuals who were enrolled in two ACTG studies that evaluated the relationship between neuropsychological performance and cerebral metabolites. Concentrations of six chemokines (fractalkine, IL-8, IP-10, MCP-1, MIP-1?, and SDF-1) were measured and compared with cerebral metabolites individually and as composite neuronal, basal ganglia, and inflammatory patterns. IP-10 and MCP-1 were the chemokines most strongly associated with individual cerebral metabolites. Specifically, (1) higher IP-10 levels correlated with lower N-acetyl aspartate (NAA)/creatine (Cr) ratios in the frontal white matter and higher MI/Cr ratios in all three brain regions considered and (2) higher MCP-1 levels correlated with lower NAA/Cr ratios in frontal white matter and the parietal cortex. IP-10, MCP-1, and IL-8 had the strongest associations with patterns of cerebral metabolites. In particular, higher levels of IP-10 correlated with lower neuronal pattern scores and higher basal ganglia and inflammatory pattern scores, the same pattern which has been associated with HIV-associated neurocognitive disorders (HAND). Subgroup analysis indicated that the effects of IP-10 and IL-8 were influenced by effective antiretroviral therapy and that memantine treatment may mitigate the neuronal effects of IP-10. This study supports the role of chemokines in HAND and the validity of MRS as an assessment tool. In particular, the findings identify relationships between the immune response-particularly an interferon-inducible chemokine, IP-10-and cerebral metabolites and suggest that antiretroviral therapy and memantine modify the impact of the immune response on neurons.
Related JoVE Video
Cerebral metabolite abnormalities in human immunodeficiency virus are associated with cortical and subcortical volumes.
J. Neurovirol.
PUBLISHED: 10-20-2010
Show Abstract
Hide Abstract
Cerebral metabolite disturbances occur among human immunodeficiency virus (HIV)-infected people, and are thought to reflect neuropathology, including proinflammatory processes, and neuronal loss. HIV-associated cortical atrophy continues to occur, though its basis is not well understood, and the relationship of cerebral metabolic disturbance to structural brain abnormalities in HIV has not been well delineated. We hypothesized that metabolite disturbances would be associated with reduced cortical and subcortical volumes. Cerebral volumes were measured in 67 HIV-infected people, including 10 people with mild dementia (acquired immunodeficiency syndrome [AIDS] dimentia complex [ADC] stage >1) via automated magnetic resonance imaging (MRI) segmentation. Magnetic resonance spectroscopy (MRS) was used to measure levels of cerebral metabolites N-acetylaspartate (NAA), myo-inositol (MI), choline-containing compounds (Cho), glutamate/glutamine (Glx), and creatine (Cr) from three brain regions (frontal gray matter, frontal white matter, basal ganglia). Analyses were conducted to examine the associations between MRS and cerebral volumetric measures using both absolute and relative metabolite concentrations. NAA in the mid-frontal gray matter was most consistently associated with cortical (global, frontal, and parietal), ventricular, and caudate volumes based on analysis of absolute metabolite levels, whereas temporal lobe volume was associated with basal ganglia NAA and Glx, and Cho concentrations in the frontal cortex and basal ganglia. Hippocampal volume was associated with frontal white matter NAA, whereas thalamic volume was associated with both frontal white matter NAA and basal ganglia Glx. Analyses of relative metabolite concentrations (referenced to Cr) yielded weaker effects, although more metabolites were retained as significant predictors in the models than the analysis of absolute concentrations. These findings demonstrate that reduced cortical and subcortical volumes, which have been previously found to be linked to HIV status and history, are also strongly associated with the degree of cerebral metabolite disturbance observed via MRS. Reduced cortical and hippocampal volumes were most strongly associated with decreased NAA, though reduced Glx also tended to be associated with reduced cortical and subcortical volumes (caudate and thalamus) as well, suggesting both neuronal and glial disturbances. Interestingly, metabolite-volumetric relationships were not limited to the cortical region from which MRS was measured, possibly reflecting shared pathophysiological processes. The relationships between Cho and volumetric measures suggest a complicated relationship possibly related to the effects of inflammatory processes on brain volume. The findings demonstrate the relationship between MRI-derived measures of cerebral metabolite disturbances and structural brain integrity, which has implication in understanding HIV-associated neuropathological mechanisms.
Related JoVE Video
Experience implementing electronic health records in three East African countries.
Stud Health Technol Inform
PUBLISHED: 09-16-2010
Show Abstract
Hide Abstract
Efficient use of health care resources in low-income countries by providers and local and national managers requires timely access to patient data.
Related JoVE Video
Retention in care among HIV-infected patients in resource-limited settings: emerging insights and new directions.
Curr HIV/AIDS Rep
PUBLISHED: 09-08-2010
Show Abstract
Hide Abstract
In resource-limited settings--where a massive scale-up of HIV services has occurred in the last 5 years--both understanding the extent of and improving retention in care presents special challenges. First, retention in care within the decentralizing network of services is likely higher than existing estimates that account only for retention in clinic, and therefore antiretroviral therapy services may be more effective than currently believed. Second, both magnitude and determinants of patient retention vary substantially and therefore encouraging the conduct of locally relevant epidemiology is needed to inform programmatic decisions. Third, socio-structural factors such as program characteristics, transportation, poverty, work/child care responsibilities, and social relations are the major determinants of retention in care, and therefore interventions to improve retention in care should focus on implementation strategies. Research to assess and improve retention in care for HIV-infected patients can be strengthened by incorporating novel methods such as sampling-based approaches and a causal analytic framework.
Related JoVE Video
Invasive intraductal papillary mucinous neoplasm: predictors of survival and role of adjuvant therapy.
HPB (Oxford)
PUBLISHED: 09-07-2010
Show Abstract
Hide Abstract
Adjuvant treatment for pancreatic adenocarcinoma has been shown to improve survival. An increasingly recognized subtype of pancreatic adenocarcinoma is invasive intraductal papillary mucinous neoplasm (IPMN). It is unclear whether adjuvant treatment for invasive IPMN improves survival. This study aimed to determine the impact of adjuvant treatment in invasive IPMN.
Related JoVE Video
Accuracy and cut-off point selection in three-class classification problems using a generalization of the Youden index.
Stat Med
PUBLISHED: 09-03-2010
Show Abstract
Hide Abstract
We study properties of the index J(3), defined as the accuracy, or the maximum correct classification, for a given three-class classification problem. Specifically, using J(3) one can assess the discrimination between the three distributions and obtain an optimal pair of cut-off points c(1)
Related JoVE Video
Tracking a sample of patients lost to follow-up has a major impact on understanding determinants of survival in HIV-infected patients on antiretroviral therapy in Africa.
Trop. Med. Int. Health
PUBLISHED: 07-01-2010
Show Abstract
Hide Abstract
To date, data regarding the determinants of mortality in HIV-infected patients starting antiretroviral therapy (ART) in Africa have been primarily derived from routine clinical care settings practicing the public health approach. Losses to follow-up, however, are high in these settings and may lead to bias in understanding the determinants of mortality.
Related JoVE Video
Retention of HIV-infected and HIV-exposed children in a comprehensive HIV clinical care programme in Western Kenya.
Trop. Med. Int. Health
PUBLISHED: 05-14-2010
Show Abstract
Hide Abstract
To describe incidence rates (IR) and risk factors for loss-to-follow-up (LTFU) among HIV-infected and HIV-exposed children in a large HIV treatment programme in Western Kenya.
Related JoVE Video
Adjusting mortality for loss to follow-up: analysis of five ART programmes in sub-Saharan Africa.
PLoS ONE
PUBLISHED: 04-08-2010
Show Abstract
Hide Abstract
Evaluation of antiretroviral treatment (ART) programmes in sub-Saharan Africa is difficult because many patients are lost to follow-up. Outcomes in these patients are generally unknown but studies tracing patients have shown mortality to be high. We adjusted programme-level mortality in the first year of antiretroviral treatment (ART) for excess mortality in patients lost to follow-up.
Related JoVE Video
Outcomes of HIV-exposed children in western Kenya: efficacy of prevention of mother to child transmission in a resource-constrained setting.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 03-13-2010
Show Abstract
Hide Abstract
To compare rates of mother to child transmission of HIV and infant survival in women-infant dyads receiving different interventions in a prevention of Mother to Child Transmission (pMTCT) program in western Kenya.
Related JoVE Video
Effects of nadir CD4 count and duration of human immunodeficiency virus infection on brain volumes in the highly active antiretroviral therapy era.
J. Neurovirol.
PUBLISHED: 02-02-2010
Show Abstract
Hide Abstract
Cerebral atrophy is a well-described, but poorly understood complication of human immunodeficiency virus (HIV) infection. Despite reduced prevalence of HIV-associated dementia in the highly active antiretroviral therapy (HAART) era, HIV continues to affect the brains of patients with chronic infection. In this study we examine patterns of brain volume loss in HIV-infected patients on HAART, and demographic and clinical factors contributing to brain volume loss. We hypothesized that nadir CD4+ lymphocyte count, duration of HIV infection, and age would be associated with reduced cortical volumes. Volumes of cortical and subcortical regions in 69 HIV-infected neuroasymptomatic (NA) individuals and 13 with at least mild acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) were measured using voxel-based morphometry. Demographic and clinical factors (age, plasma HIV RNA level, current and nadir CD4 counts, duration of infection, central nervous system [CNS] penetration of antiretroviral regimen) along with their interactions were entered into a regression model selection algorithm to determine the final models that best described regional brain volumes. Relative to NA, individuals with ADC exhibited decreased total gray matter and parietal cortex volumes and increased total ventricular volumes. Final regression models showed overall cerebral volume, including gray and white matter volume and volumes of the parietal, temporal, and frontal lobes and the hippocampus, were most strongly associated with disease history factors (nadir CD4 and duration of infection). In contrast, basal ganglia volumes were related most strongly to current disease factors, most notably plasma HIV RNA. These findings indicate that individuals with a history of chronic HIV infection with previous episodes of severely impaired immune function, as reflected by reduced nadir CD4+ lymphocyte count, may be at greatest risk for cerebral atrophy. The pattern of HIV-associated brain loss may be changing from a subcortical to a cortical disease among patients who are largely asymptomatic on HAART.
Related JoVE Video
Influence of gender on loss to follow-up in a large HIV treatment programme in western Kenya.
Bull. World Health Organ.
PUBLISHED: 01-13-2010
Show Abstract
Hide Abstract
To determine the incidence of loss to follow-up in a treatment programme for people living with human immunodeficiency virus (HIV) infection in Kenya and to investigate how loss to follow-up is affected by gender.
Related JoVE Video
Modeling AIDS survival after initiation of antiretroviral treatment by Weibull models with changepoints.
J Int AIDS Soc
PUBLISHED: 06-26-2009
Show Abstract
Hide Abstract
Mortality of HIV-infected patients initiating antiretroviral therapy in the developing world is very high immediately after the start of ART therapy and drops sharply thereafter. It is necessary to use models of survival time that reflect this change.
Related JoVE Video
The need for double-sampling designs in survival studies: an application to monitor PEPFAR.
Biometrics
PUBLISHED: 06-06-2009
Show Abstract
Hide Abstract
In 2007, there were 33.2 million people around the world living with HIV/AIDS (UNAIDS/WHO, 2007). In May 2003, the U.S. President announced a global program, known as the Presidents Emergency Plan for AIDS Relief (PEPFAR), to address this epidemic. We seek to estimate patient mortality in PEPFAR in an effort to monitor and evaluate this program. This effort, however, is hampered by loss to follow-up that occurs at very high rates. As a consequence, standard survival data and analysis on observed nondropout data are generally biased, and provide no objective evidence to correct the potential bias. In this article, we apply double-sampling designs and methodology to PEPFAR data, and we obtain substantially different and more plausible estimates compared with standard methods (1-year mortality estimate of 9.6% compared to 1.7%). The results indicate that a double-sampling design is critical in providing objective evidence of possible nonignorable dropout and, thus, in obtaining accurate data in PEPFAR. Moreover, we show the need for appropriate analysis methods coupled with double-sampling designs.
Related JoVE Video
The clinical burden of tuberculosis among human immunodeficiency virus-infected children in Western Kenya and the impact of combination antiretroviral treatment.
Pediatr. Infect. Dis. J.
PUBLISHED: 05-20-2009
Show Abstract
Hide Abstract
The burden of tuberculosis (TB) disease in children, particularly in HIV-infected children, is poorly described because of a lack of effective diagnostic tests and the emphasis of public health programs on transmissible TB.
Related JoVE Video
Related JoVE Video
Stereotactic body radiation therapy for early-stage non-small-cell lung carcinoma: four-year results of a prospective phase II study.
Int. J. Radiat. Oncol. Biol. Phys.
PUBLISHED: 02-27-2009
Show Abstract
Hide Abstract
The 50-month results of a prospective Phase II trial of stereotactic body radiation therapy (SBRT) in medically inoperable patients are reported.
Related JoVE Video
Pancreatic fistula following pancreaticoduodenectomy: clinical predictors and patient outcomes.
HPB Surg
PUBLISHED: 01-27-2009
Show Abstract
Hide Abstract
Pancreatic fistula continues to be a common complication following PD. This study seeks to identify clinical factors which may predict pancreatic fistula (PF) and evaluate the effect of PF on outcomes following pancreaticoduodenectomy (PD). We performed a retrospective analysis of a clinical database at an academic tertiary care hospital with a high volume of pancreatic surgery. Five hundred ten consecutive patients underwent PD, and PF occurred in 46 patients (9%). Perioperative mortality of patients with PF was 0%. Forty-five of 46 PF (98%) closed without reoperation with a mean time to closure of 34 days. Patients who developed PF showed a higher incidence of wound infection, intra-abdominal abscess, need for reoperation, and hospital length of stay. Multivariate analysis demonstrated an invaginated pancreatic anastomosis and closed suction intraperitoneal drainage were associated with PF whereas a diagnosis of chronic pancreatitis and endoscopic stenting conferred protection. Development of PF following PD in this series was predicted by gender, preoperative stenting, pancreatic anastomotic technique, and pancreas pathology. Outcomes in patients with PF are remarkable for a higher rate of septic complications, longer hospital stays, but in this study, no increased mortality.
Related JoVE Video
A comparison of tests for restricted orderings in the three-class case.
Stat Med
PUBLISHED: 01-22-2009
Show Abstract
Hide Abstract
A variety of methods for comparing three distributions have been proposed in the literature. These methods assess the same null hypothesis of equal distributions but differ in the alternative hypothesis they consider. The alternative hypothesis can be that measurements from the three classes are distributed according to unequal distributions or that measurements between the three classes follow a specific monotone ordering, an inverse-U-shaped (umbrella) ordering, or a U-shaped (tree) ordering. This paper compares these tests with respect to power and test size under different simulation scenarios. In addition, the methods are illustrated in two applications generated by different research questions with data from three classes suggesting monotone and umbrella orders. Additionally, proposals for the appropriate application of these tests are provided.
Related JoVE Video
The OpenMRS Implementers Network.
Int J Med Inform
PUBLISHED: 01-20-2009
Show Abstract
Hide Abstract
OpenMRS (www.openmrs.org) is a configurable open source electronic medical record application developed and maintained by a large network of open source developers coordinated by the Regenstrief Institute and Partners in Health and mainly used for HIV patient and treatment information management in Africa. Our objective is to develop an open Implementers Network for OpenMRS to provide regional support for the growing number of OpenMRS implementations in Africa and to include African developers and implementers in the future growth of OpenMRS.
Related JoVE Video
Cardiac related death in thalassaemia major: time trend and risk factors in a large Greek Unit.
Eur. J. Haematol.
PUBLISHED: 01-09-2009
Show Abstract
Hide Abstract
Cardiac complications are the leading cause of death in thalassaemic patients (TM) worldwide. Improved management protocols including new chelators and imaging have reduced cardiac-related deaths but also require more advanced analytical methods to reflect temporal fluctuations in mortality risk.
Related JoVE Video
A pilot trial of serial 18F-fluorodeoxyglucose positron emission tomography in patients with medically inoperable stage I non-small-cell lung cancer treated with hypofractionated stereotactic body radiotherapy.
Int. J. Radiat. Oncol. Biol. Phys.
PUBLISHED: 01-05-2009
Show Abstract
Hide Abstract
Routine assessment was made of tumor metabolic activity as measured by 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in Stage I non-small-cell lung cancer (NSCLC). This report describes PET correlates prospectively collected after stereotactic body radiotherapy (SBRT) for patients with medically inoperable NSCLC.
Related JoVE Video
Related JoVE Video
A causal framework for understanding the effect of losses to follow-up on epidemiologic analyses in clinic-based cohorts: the case of HIV-infected patients on antiretroviral therapy in Africa.
Am. J. Epidemiol.
Show Abstract
Hide Abstract
Although clinic-based cohorts are most representative of the "real world," they are susceptible to loss to follow-up. Strategies for managing the impact of loss to follow-up are therefore needed to maximize the value of studies conducted in these cohorts. The authors evaluated adult patients starting antiretroviral therapy at an HIV/AIDS clinic in Uganda, where 29% of patients were lost to follow-up after 2 years (January 1, 2004-September 30, 2007). Unweighted, inverse probability of censoring weighted (IPCW), and sampling-based approaches (using supplemental data from a sample of lost patients subsequently tracked in the community) were used to identify the predictive value of sex on mortality. Directed acyclic graphs (DAGs) were used to explore the structural basis for bias in each approach. Among 3,628 patients, unweighted and IPCW analyses found men to have higher mortality than women, whereas the sampling-based approach did not. DAGs encoding knowledge about the data-generating process, including the fact that death is a cause of being classified as lost to follow-up in this setting, revealed "collider" bias in the unweighted and IPCW approaches. In a clinic-based cohort in Africa, unweighted and IPCW approaches-which rely on the "missing at random" assumption-yielded biased estimates. A sampling-based approach can in general strengthen epidemiologic analyses conducted in many clinic-based cohorts, including those examining other diseases.
Related JoVE Video
Related JoVE Video

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.