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In JoVE (1)
Other Publications (51)
- East African Medical Journal
- Leprosy Review
- Hearing Research
- Taehan Kanho. The Korean Nurse
- Presse Médicale (Paris, France : 1983)
- Leprosy Review
- Biotechnology and Bioengineering
- Bulletin of the International Union Against Tuberculosis and Lung Disease
- Bulletin of the International Union Against Tuberculosis and Lung Disease
- The Medical Journal of Malaysia
- International Journal of Epidemiology
- International Journal of Leprosy and Other Mycobacterial Diseases : Official Organ of the International Leprosy Association
- Taehan Kanho. The Korean Nurse
- Archives of Pathology & Laboratory Medicine
- Tropical and Geographical Medicine
- The International Journal of Health Planning and Management
- Tubercle and Lung Disease : the Official Journal of the International Union Against Tuberculosis and Lung Disease
- International Journal of Epidemiology
- Carbohydrate Research
- AIDS (London, England)
- International Journal of Leprosy and Other Mycobacterial Diseases : Official Organ of the International Leprosy Association
- American Journal of Industrial Medicine
- Applied Biochemistry and Biotechnology
- Psychonomic Bulletin & Review
- Journal of Neuroimaging : Official Journal of the American Society of Neuroimaging
- Clinical Gastroenterology and Hepatology : the Official Clinical Practice Journal of the American Gastroenterological Association
- Mycological Research
- IEEE Transactions on Pattern Analysis and Machine Intelligence
- Journal Français D'ophtalmologie
- European Journal of Pharmacology
- Science (New York, N.Y.)
- Acta Biomaterialia
- Cardiovascular Research
- British Journal of Pharmacology
- IEEE Transactions on Pattern Analysis and Machine Intelligence
- The Journal of Thoracic and Cardiovascular Surgery
- Nephrology, Dialysis, Transplantation : Official Publication of the European Dialysis and Transplant Association - European Renal Association
- The Journal of Urology
- Journal of Vascular Research
- Fungal Genetics and Biology : FG & B
- Health & Place
- The Journal of Neuroscience : the Official Journal of the Society for Neuroscience
- Journal of Neurosurgery. Pediatrics
- The Annals of Otology, Rhinology, and Laryngology
- Nano Letters
Articles by Pak Y. Chum in JoVE
Genotyping of Plant and Animal Samples without Prior DNA Purification
Pak Y. Chum, Josh D. Haimes, Chas P. André, Pia K. Kuusisto, Melissa L. Kelley
Thermo Scientific Molecular Biology Products, Thermo Fisher Scientific
The Direct PCR approach presented here facilitates PCR amplification directly from small amounts of unpurified plant and animal tissue.
Other articles by Pak Y. Chum on PubMed
East African Medical Journal. Jul, 1970 | Pubmed ID: 5506165
Leprosy Review. Jun, 1971 | Pubmed ID: 5150032
Hearing Research. Jun, 1980 | Pubmed ID: 7410229
In Part I, the sound emitting properties of the peripheral auditory system are briefly reviewed and links with other literature are cited. (Summary of Symposium section introduction). In Part II, the stimulation of acoustic emissions by clicks is examined experimentally and analytically, in order to specify the physical qualities and parameters of the unknown generator which may be considered as driving the ear drum. Special attention is paid to absolute magnitudes to the qualitative interpretation of the generator's nonlinear properties and to the extent of inter-stimulus interactions in the time and frequency domains. New transient suppression results are presented. From the observations made, and without reference to the likely cochlear origin of the phenomenon, it is deduced that the generator is a multiple channel system, with each channel consisting of at least a steep-sloped narrow band filter followed by a fast acting compressive nonlinearity. A secondary nonlinearity seems also to be present, of a form which requires the filter itself to be nonlinear. The maximum power output of the generator is of the order 0.26 X 10(-12) W.
Functional Properties of Lyophilized Hemoglobin in the Presence of Amino Acids After 13 Months of Conservation
Experientia. 1981 | Pubmed ID: 7297647
Taehan Kanho. The Korean Nurse. Aug, 1983 | Pubmed ID: 6555423
Presse Médicale (Paris, France : 1983). Feb, 1986 | Pubmed ID: 2938119
Osteosynthesis for fractures of the metacarpals using a simplified system of Kirschner wires introduced percutaneously and maintained by an acrylic cement bridge has been performed in 40 patients. Consolidation was obtained consistently, within one month on average, with almost no morbidity and virtually without sequelae. This procedure is extremely simple and can be used for all extra-articular fractures of the metacarpals with displacement.
Leprosy Review. 1986 | Pubmed ID: 3573963
Organosolv Pretreatment for Enzymatic Hydrolysis of Poplars: I. Enzyme Hydrolysis of Cellulosic Residues
Biotechnology and Bioengineering. May, 1988 | Pubmed ID: 18584659
Aspen (Populus tremuloides) and black cottonwood (Populus trichocarpa) organosolv pulps produced in a wide range of solvent composition (between 30 and 70% by volume of methanol) and catalysts (H(2)SO(4) and H(3)PO(4)) such that the cooking liquor pH = 3 are easily digested by enzymes. The total yields of hydrolysis residues (pulps) are in the 40-60% range; the acid-catalyzed delignification followed by enzyme hydrolysis can generate 70-88% of the original six-carbon sugars contained in the wood. Glucomannan and arablnogalactan are dissolved into the pulping liquor in the pH range of 2-4.5. Lower pH (=3) leads to additional solubilization of six-carbon sugars. These sugars may be fermented directly. From the insoluble hydrolysis residues, 36-41% conversions of wood into fermentable sugars were obtained after enzyme hydrolysis; the starting feedstocks contain 50.8 and 46.6% hexosans, respectively, for aspen and black cotton-wood. The kinetics of enzymatic hydrolysis of cellulose can be formally treated as two simultaneous pseudo-first-order reactions in which fast and slow hydrolyses of cellulose occur. Correlations between the glucan digestibility and the effect of the pretreatment have been made. The higher residual xylan content reduces the amount of the rapidly hydrolyzable glucan fraction and lowers the glucan digestibility. The proposed simple kinetic treatment is very helpful in assessing the effect of the pretreatment on pulp enzyme hydrolyzability.
Bulletin of the International Union Against Tuberculosis and Lung Disease. Sep, 1989 | Pubmed ID: 2627585
Bulletin of the International Union Against Tuberculosis and Lung Disease. 1990-1991 | Pubmed ID: 1983757
Cost Effectiveness of Chemotherapy for Pulmonary Tuberculosis in Three Sub-Saharan African Countries
Lancet. Nov, 1991 | Pubmed ID: 1682693
The value of programmes to control pulmonary tuberculosis in developing countries remains the subject of debate. We have examined the cost-effectiveness of chemotherapy programmes for the control of pulmonary sputum-smear-positive tuberculosis in Malawi, Mozambique, and Tanzania. Effective cure rates of 86-90% were achieved with short-course chemotherapy and of 60-66% with standard chemotherapy. The average incremental costs per year of life saved were US $1.7-2.1 for short-course chemotherapy with hospital admission, $2.4-3.4 for standard chemotherapy with hospital admission, $0.9-1.1 for ambulatory short-course chemotherapy, and $0.9-1.3 for ambulatory standard chemotherapy. Chemotherapy for smear-positive tuberculosis is thus cheaper than other cost-effective health interventions such as immunisation against measles and oral rehydration therapy. Because the greatest benefit of chemotherapy is reduced transmission of the bacillus, treating HIV-seropositive, tuberculosis smear-positive patients would be only slightly less cost-effective than treating HIV-seronegative, tuberculosis-smear-positive patients.
The Medical Journal of Malaysia. Sep, 1992 | Pubmed ID: 1491649
A six year old Chinese boy with relapsed Acute Promyelocytic Leukaemia (APML) failed to respond to reinduction with Daunorubicin and Cytarabine infusion. He was successfully treated with all trans-Retinoic Acid (45 mg/m2/day) orally. After four weeks of treatment, he was in complete remission. The side effects of all trans-Retinoic Acid were negligible.
HIV-1 Infection As a Risk Factor for the Development of Tuberculosis: a Case-control Study in Tanzania
International Journal of Epidemiology. Dec, 1993 | Pubmed ID: 8144300
A population-based case-control study was carried out in Mwanza Region, Tanzania, to determine the relative and population attributable risk of human immunodeficiency virus type 1 (HIV-1) infection for developing active tuberculosis. Cases were 441 consecutively diagnosed patients with tuberculosis (all types), aged 15-54 years. Controls were a representative population sample of 4161 people, drawn in a stratified cluster sample from urban areas, roadside settlements, and rural villages. HIV-1 infection was determined by ELISA and if the ELISA result was indeterminate by Western Blot. The HIV-1 prevalence in cases was 23.0% in rural, 32.1% in roadside, and 54.1% in urban areas, while in controls these prevalences were 3.4%, 7.2% and 12.1% respectively. The relative risk (RR) of HIV-1 infection for the development of active tuberculosis was estimated to be 8.3 (95% confidence interval [CI] 6.4-11.0). This risk varied little by sex or residence, but appeared to be more pronounced in the age group 25-34 years. The case detection rate of tuberculosis in those aged 15-54 years was 125/100,000 people per year. The population attributable risk was 36/100,000 people per year, implying that 29% of tuberculosis cases at present may be attributable to HIV-1 infection. It is concluded that HIV-1 infection is a major contributing factor to the increased case detection rate of tuberculosis observed over the past 10 years in Mwanza Region. If the prevalence of HIV-1 continues to increase, the incidence of tuberculosis will continue to rise as well.(ABSTRACT TRUNCATED AT 250 WORDS)
International Journal of Leprosy and Other Mycobacterial Diseases : Official Organ of the International Leprosy Association. Dec, 1993 | Pubmed ID: 8151186
A case-control study was carried out in Tanzania to determine the relative risk of those with HIV-1 infection for getting leprosy. Cases were 93 consecutively diagnosed patients with leprosy aged 15-54 years from the Mwanza Region. Controls were a representative population sample of 4161 people drawn from a stratified cluster sample from urban areas, roadside settlements, and rural villages. HIV-1 infection was determined by enzyme-linked immunosorbent assay (ELISA); Western blot was used when the ELISA result was indeterminate. The HIV-1 prevalence in leprosy cases was 10% in rural (7 of 72) and in roadside and urban areas (2 of 21); in controls these prevalences were 3.4% and 9.9%, respectively. The relative risk of HIV-1 infection for the development of leprosy was estimated to be 2.2 [95% confidence interval (CI) = 1.0-4.7; p = 0.07]. HIV-1 infection was significantly associated with multibacillary (MB) leprosy (odds ratio 4.6; CI = 1.3-13.2) but not with paucibacillary leprosy (odds ratio 1.4; 95% CI = 0.4-3.8). The population etiological fraction for the development of MB leprosy attributable to HIV-1 infection in this population is estimated to be 13% (95% CI = 4%-23%). We conclude that HIV-1 is a risk factor for the development of MB leprosy. The impact of the HIV-1 epidemic on the incidence of leprosy so far has been limited since HIV-1 occurs mainly in urban areas and leprosy in rural areas.
Taehan Kanho. The Korean Nurse. May-Jun, 1993 | Pubmed ID: 8231054
The purpose of this study was to develop a strategy for the promotion of the image of nursing. The study questions were: Do nurses have a proper self image? What image of nursing do the public have? It is thought that the prejudices that the public have about nursing personnel have to be eliminated in order to provide for better health care. Even though the public have misconceptions of prejudices, nurses have not paid much attention to them, nor sought ways to change them. This study was designated to make out a model project to improve the image of nursing held by the public. This study was a strategy building descriptive study. This study was oriented to a model project to improve the image of nursing. The subjects for the study were 650 nurses who were staff nurses. The study procedures were as follow: First step: a special action committee for nursing image making was established of nine members who were divided into five subgroups. 2nd step: a 1st workshop was held to improve self concept of nurses and to recognize them the necessity of nursing image development, a 2nd workshop was held to develop a conceptual framework for the action plan and for budget planning. 3rd step: a master plan for a nursing image was developed and evaluated through discussion and presentation. 4th step: lecture and role playing were used to further the development of a caring attitude in the nurse.(ABSTRACT TRUNCATED AT 250 WORDS)
Archives of Pathology & Laboratory Medicine. May, 1993 | Pubmed ID: 7683871
We report two cases of placental site nodule in which Mallory's bodies were found in the intermediate trophoblasts constituting the lesion. Mallory's bodies are known to occur in hepatocytes and pulmonary alveolar cells in a wide variety of conditions, and represent abnormal cytoplasmic aggregates of cytokeratin intermediate filaments. Their occurrence outside the liver and lung is exceptional. In the present cases, they were immunoreactive for both low- and high-molecular-weight cytokeratins. Since high-molecular-weight cytokeratin is not normally expressed in intermediate trophoblasts, the formation of Mallory's bodies appears to involve aberrant expression of cytoskeletal proteins.
Chest Radiography and Beta-2-microglobulin Levels in HIV-seronegative and HIV-seropositive African Patients with Pulmonary Tuberculosis
Tropical and Geographical Medicine. 1994 | Pubmed ID: 7855913
To examine the relationship between radiographic features, serum beta-2-microglobulin (beta-2-M) levels, results of sputum-smear microscopy and outcome, we performed a retrospective study of 99 HIV-seropositive and 162 HIV-seronegative patients with pulmonary tuberculosis (TB) in Dar es Salaam, Tanzania. Radiographic features of primary TB were more common and features of postprimary TB less common in HIV-seropositive compared to seronegative patients (50% vs 31%, p < 0.002; and 40% vs 63%, p < 0.001), respectively). HIV infection had a strong independent effect on the beta-2-M levels. Among HIV-infected patients radiographic findings of primary TB were significantly more often associated with beta-2-M levels of > 4 mg/l than features of postprimary TB (71.1% vs 44.4%, p < 0.02). In patients with features of postprimary TB, acid-fast bacilli were more often detected in sputum smears than in patients with primary TB (65% vs 47%, p > 0.05, in HIV-seropositive patients; and 63% vs 31%, p < 0.001) in seronegative patients). The observed mortality was too low to identify radiographic predictors of survival. We conclude that HIV-infected patients with features of primary pulmonary TB are likely in an advanced stage of HIV infection and deserve close supervision during anti-tuberculous therapy.
Cost-effectiveness of Chemotherapy for Sputum Smear-positive Pulmonary Tuberculosis in Malawi, Mozambique and Tanzania
The International Journal of Health Planning and Management. Apr-Jun, 1994 | Pubmed ID: 10172113
The cost-effectiveness of chemotherapy for pulmonary sputum smear-positive tuberculosis was examined in the national tuberculosis control programmes of Malawi, Mozambique and Tanzania. In these three programmes, routine cure rates have exceeded 80 per cent. Average, average incremental and marginal unit costs for standard, short-course and retreatment regimens with and without hospitalization have been measured. The average incremental cost per year of life saved through chemotherapy ranged from US $0.90-3.10. In all conditions, short-course chemotherapy is preferable to standard 12-month chemotherapy. When hospitalization during the intensive phase of chemotherapy increases the cure rate by 10-15 percentage points, it can be relatively cost-effective. Analysing the cost-effectiveness of short-course and standard chemotherapy, where the depth of the margin of benefit is different, illustrates some of the dangers of simplistic use of cost-effectiveness ratios.
Impact of the Change from an Injectable to a Fully Oral Regimen on Patient Adherence to Ambulatory Tuberculosis Treatment in Dar Es Salaam, Tanzania
Tubercle and Lung Disease : the Official Journal of the International Union Against Tuberculosis and Lung Disease. Aug, 1995 | Pubmed ID: 7579308
To measure the impact on patient adherence to directly observed ambulatory tuberculosis treatment substituting an all-oral treatment regimen for a regimen containing streptomycin.
International Journal of Epidemiology. Jun, 1995 | Pubmed ID: 7672908
Routine data obtained from the National Tuberculosis and Leprosy Programme (NTLP) of Tanzania have shown a constant increase in the notified number of tuberculosis (TB) cases since 1982. Possible causes include an improved reporting system, improvement in health services after the introduction of short course chemotherapy (SCC), and human immunodeficiency virus (HIV) infection. This paper examines to what extent the increased TB case detection rate can be attributed to HIV infection, by calculating the population attributable risk for various years.
Mass Spectrometric Studies of the Thermal Decomposition of Carbohydrates Using 13C-labeled Cellulose and Glucose
Carbohydrate Research. Feb, 1996 | Pubmed ID: 8721146
The mechanism of the thermal decomposition of carbohydrates is very important to the development of fuels, fibers, and paper products. To help gain more insight into the pyrolysis chemistry of cellulose, we have carried out experimental studies using Acetobacter xylinum cellulose grown on D-(1-13C)-glucose medium with incorporation levels of 1-13C of 14%, as determined by 13C NMR analysis. Samples of the labeled cellulose, as well as D-(1-13C)- and D-(2-13C)-glucose, were pyrolyzed under fast-heating conditions and the products analyzed by molecular beam mass spectrometry (MBMS). From the labeled cellulose samples, statistically significant levels of enrichment were observed for the pyrolysis products that occur at m/z 110, 114, 126, 144, and 191, but not at m/z 98, 60, or 31. The lack of enrichment in the latter fragments indicates that they do not incorporate C-1. Samples were treated with 0.1% aqueous KOH to favor the formation of glycolaldehyde, but even in this case this major product was not enriched. These results suggest that the m/z 60 ion is an EI fragment ion of levoglucosan, formed by loss of neutral species containing C-1. However, the m/z 191 ion was found to contain two C-1 carbons. Collision-induced dissociation results for this ion suggest that it consists of a formate group. The structure of this ion is proposed to be the protonated formate of levoglucosan at the C-4 position, derived from either a reverse aldol reaction or a (+/-)-Diels-Alder reaction. The (1-13C)-glucose pyrolysis product distribution is similar to that for (1-13C)-labeled cellulose. The (2-13C)-glucose pyrolysis product distribution shows significant contribution from C-2 at the M + 1 peaks of m/z 32, 43, 60, 73, 85, and 97, indicating major incorporations of C-2 in glycolaldehyde in contrast to the lack of incorporation of the C-1 position in this major product.
AIDS (London, England). Mar, 1996 | Pubmed ID: 8882670
In Tanzania during the past 6 years reported tuberculosis (TB) cases have nearly doubled, with proportionately much greater increases in smear-negative and extrapulmonary cases compared with smear-positive cases. At the same time, HIV infection has become widespread throughout the country. This survey was undertaken in order to study the association of TB and HIV and to determine the impact of HIV on present and future TB cases in Tanzania.
International Journal of Leprosy and Other Mycobacterial Diseases : Official Organ of the International Leprosy Association. Jun, 1997 | Pubmed ID: 9251592
An epidemiological study of the interaction of leprosy and HIV infection in Tanzania.
American Journal of Industrial Medicine. Jun, 1999 | Pubmed ID: 10332510
Inhalational exposure to zinc oxide fumes is associated with metal fume fever, a self-limited but very uncomfortable condition closely resembling influenza. Very little is known regarding the toxicokinetics of inhaled zinc, making the interpretation of zinc measurements in serum and urine problematic.
BioTechniques. Nov, 2005 | Pubmed ID: 16312212
Applied Biochemistry and Biotechnology. Mar, 2007 | Pubmed ID: 17625236
The precise quantitative analysis of biomass sugars is a very important step in the conversion of biomass feedstocks to fuels and chemicals. However, the most accurate method of biomass sugar analysis is based on the gas chromatography analysis of derivatized sugars either as alditol acetates or trimethylsilanes. The derivatization method is time consuming but the alternative high-performance liquid chromatography (HPLC) method cannot resolve most sugars found in biomass hydrolysates. We have demonstrated for the first time that by careful manipulation of the HPLC mobile phase, biomass monomeric sugars (arabinose, xylose, fructose, glucose, mannose, and galactose) can be analyzed quantitatively and there is excellent baseline resolution of all the sugars. This method was demonstrated for standard sugars, pretreated corn stover liquid and solid fractions. Our method can also be used to analyze dimeric sugars (cellobiose and sucrose).
Neurology. Sep, 2007 | Pubmed ID: 17893296
To determine the frequency and significance of electrographic seizures and other EEG findings in patients with intracerebral hemorrhage (ICH).
Psychonomic Bulletin & Review. Dec, 2007 | Pubmed ID: 18229495
The spatial working memory system constantly updates spatial representations and many studies have focused on the underlying principles of the encoding and maintenance of visual information. Here we investigated the question of how the production of actions influences spatial working memory. Participants were given a task that required concurrent maintenance of two spatial arrays, one encoded by visual observation accompanied with pointing movements, the other by only visual observation. Across two experiments, movement during encoding was found to facilitate recognition of spatial arrays in a load-dependent manner. The results suggest an action-based encoding principle within the working memory system, and possible underlying action-related mechanisms are discussed.
Journal of Neuroimaging : Official Journal of the American Society of Neuroimaging. Oct, 2008 | Pubmed ID: 18321248
Hypertensive encephalopathy typically presents with headache and confusion and bilateral parietooccipital vasogenic edema. Brain stem and cerebellar edema in hypertensive encephalopathy usually occurs in association with these typical supratentorial changes and is usually asymptomatic. We report here an uncommon hypertensive patient with isolated, severe, and symptomatic brain stem and cerebellar edema with fourth ventricular obstruction and mild hydrocephalus. Rapid treatment of hypertension resulted in clinical and radiological improvement. Prompt recognition of the cause and aggressive treatment of hypertension in such patients are crucial to relieve edema and prevent life-threatening progression.
Assessment of Fibrosis by Transient Elastography Compared with Liver Biopsy and Morphometry in Chronic Liver Diseases
Clinical Gastroenterology and Hepatology : the Official Clinical Practice Journal of the American Gastroenterological Association. Sep, 2008 | Pubmed ID: 18456573
Liver stiffness measurement (LSM) with transient elastography (Fibroscan) can accurately diagnose advanced liver fibrosis, but its performance in early liver fibrosis is less satisfactory. We aimed to study the diagnostic performance of LSM for histologic bridging fibrosis and cirrhosis in various chronic liver diseases and to investigate the effects of liver fibrosis distribution on LSM.
Gene Expression Studies of the Dikaryotic Mycelium and Primordium of Lentinula Edodes by Serial Analysis of Gene Expression
Mycological Research. Aug, 2008 | Pubmed ID: 18555678
Lentinula edodes (Shiitake mushroom) is a common edible mushroom that has high nutritional and medical value. Although a number of genes involved in the fruit of the species have been identified, little is known about the process of differentiation from dikaryotic mycelium to primordium. In this study, serial analysis of gene expression (SAGE) was applied to determine the gene expression profiles of the dikaryotic mycelium and primordium of L. edodes in an effort to advance our understanding of the molecular basis of fruit body development. A total of 6363 tags were extracted (3278 from the dikaryotic mycelium and 3085 from the primordium), 164 unique tags matched the in-house expressed sequence tag (EST) database. The difference between the expression profiles of the dikaryotic mycelium and primordium suggests that a specific set of genes is required for fruit body development. In the transition from the mycelium to the primordium, different hydrophobins were expressed abundantly, fewer structural genes were expressed, transcription and translation became active, different genes became involved in intracellular trafficking, and stress responses were expressed. These findings advance our understanding of fruit body development. We used cDNA microarray hybridization and Northern blotting to verify the SAGE results, and found SAGE to be highly efficient in the performance of transcriptome analysis. To our knowledge, this is the first SAGE study of a mushroom.
IEEE Transactions on Pattern Analysis and Machine Intelligence. Aug, 2008 | Pubmed ID: 18566499
A randomized model verification strategy for RANSAC is presented. The proposed method finds, like RANSAC, a solution that is optimal with user-specified probability. The solution is found in time that is (i) close to the shortest possible and (ii) superior to any deterministic verification strategy. A provably fastest model verification strategy is designed for the (theoretical) situation when the contamination of data by outliers is known. In this case, the algorithm is the fastest possible (on average) of all randomized \\RANSAC algorithms guaranteeing a confidence in the solution. The derivation of the optimality property is based on Wald's theory of sequential decision making, in particular a modified sequential probability ratio test (SPRT). Next, the R-RANSAC with SPRT algorithm is introduced. The algorithm removes the requirement for a priori knowledge of the fraction of outliers and estimates the quantity online. We show experimentally that on standard test data the method has performance close to the theoretically optimal and is 2 to 10 times faster than standard RANSAC and is up to 4 times faster than previously published methods.
Journal Français D'ophtalmologie. Oct, 2008 | Pubmed ID: 19107041
To assess the patient characteristics, risk factors, and outcomes of penetrating keratoplasty wound dehiscence.
Diabetes Modulates Capacitative Calcium Entry and Expression of Transient Receptor Potential Canonical Channels in Human Saphenous Vein
European Journal of Pharmacology. Jun, 2009 | Pubmed ID: 19393642
Diabetes is associated with a perturbation of signaling pathways in vascular tissue, which causes vasomotor dysfunction such as hypertension. We have previously demonstrated that vessels from diabetic patients were more contractile than those from non-diabetic. However, in human vessels, the receptor-stimulated contraction is mainly due to enzymatic, rather than calcium signaling pathway. In this study, we hypothesized that the differential contractile response between diabetic and non-diabetic human vessels could be due to the receptor signaling to sarcoplasmic reticulum and the regulation of capacitative calcium entry. In saphenous vein samples (n=20) collected from diabetic patients undergoing bypass surgery, the contraction initiated by the addition of the sarco-endoplasmatic reticulum calcium ATPase blocker, cyclopiazonic acid, was significantly higher than that in the vessels from non-diabetic patients (n=26) (84.0+/-14.9% vs 44.2+/-9.2%), and this contraction was inhibited by SKF-96365, an inhibitor of store-operated calcium channels. Pre-incubation with indomethacin reduced the cyclopiazonic acid-induced contraction in the non-diabetic veins, but had no effect on the diabetic ones. The gene expression of transient receptor potential canonical channels (TRPC)4 was upregulated by 22% in the diabetic vessels compared with the non-diabetic ones. However, the protein expression of TRPC1 and TRPC6 was downregulated in the diabetic group by 50%. We concluded that diabetes would modulate the capacitative calcium entry likely through the store-operated calcium channel specifically via the regulation of TRPC.
Science (New York, N.Y.). May, 2009 | Pubmed ID: 19423805
Porcine Bone Marrow Stromal Cell Differentiation on Heparin-adsorbed Poly(e-caprolactone)-tricalcium Phosphate-collagen Scaffolds
Acta Biomaterialia. Nov, 2009 | Pubmed ID: 19463975
We evaluate the potential of heparin as a substrate component for the fabrication of bone tissue engineering constructs using poly(e-caprolactone)-tricalcium phosphate-collagen type I (PCL-TCP-Col) three-dimensional (3-D) scaffolds. First we explored the ability of porcine bone marrow precursor cells (MPCs) to differentiate down both the adipogenic and osteogenic pathways within 2-D culture systems, with positive results confirmed by Oil-Red-O and Alizarin Red staining, respectively. Secondly, we examined the influence of heparin on the interaction and behaviour of MPCs when seeded onto PCL-TCP-Col 3-D scaffolds, followed by their induction into the osteogenic lineage. Our 3-D findings suggest that cell metabolism and proliferation increased between days 1 and 14, with deposition of extracellular matrix also observed up to 28 days. However, no noticeable difference could be detected in the extent of osteogenesis for PCL-TCP-Col scaffolds groups with the addition of heparin compared to identical control scaffolds without the addition of heparin.
Matrix Metalloproteinase-2 and -9 Exacerbate Arterial Stiffening and Angiogenesis in Diabetes and Chronic Kidney Disease
Cardiovascular Research. Dec, 2009 | Pubmed ID: 19617223
Chronic kidney disease (CKD) and diabetes are the prominent risk factors of cardiovascular disease (CVD). Matrix metalloproteinase (MMP)-2 and -9 regulate vascular structure by degrading elastic fibre and inhibit angiogenesis by generating angiostatin. We hypothesized that MMP-2 and -9 were up-regulated in the arterial vasculature from CKD patients with diabetes, compared with those without diabetes.
Upregulation of Matrix Metalloproteinase-2 in the Arterial Vasculature Contributes to Stiffening and Vasomotor Dysfunction in Patients with Chronic Kidney Disease
Circulation. Sep, 2009 | Pubmed ID: 19687355
Cardiovascular disease is the leading cause of mortality in chronic kidney disease patients on maintenance dialysis. Given the importance of matrix metalloproteinase-2 (MMP-2) in matrix integrity, vascular cell function, and structural stability, we hypothesized that MMP-2 was elevated in the macrovasculature in dialyzed chronic kidney disease patients compared with chronic kidney disease patients not on dialysis and kidney donors.
Long-term Effects of Losartan on Structure and Function of the Thoracic Aorta in a Mouse Model of Marfan Syndrome
British Journal of Pharmacology. Nov, 2009 | Pubmed ID: 19814725
During development of thoracic aortic aneurysms in a mouse model of Marfan syndrome, upregulation of matrix metalloproteinase (MMP)-2 and -9 was accompanied by compromised aortic constriction and endothelium-dependent relaxation. Losartan has been proposed for the prevention of thoracic aortic aneurysm. We hypothesized that losartan would suppress MMP-2/-9 activation and improve aortic vasomotor function in this model.
IEEE Transactions on Pattern Analysis and Machine Intelligence. Feb, 2010 | Pubmed ID: 20075465
We propose a randomized data mining method that finds clusters of spatially overlapping images. The core of the method relies on the min-Hash algorithm for fast detection of pairs of images with spatial overlap, the so-called cluster seeds. The seeds are then used as visual queries to obtain clusters which are formed as transitive closures of sets of partially overlapping images that include the seed. We show that the probability of finding a seed for an image cluster rapidly increases with the size of the cluster. The properties and performance of the algorithm are demonstrated on data sets with 10(4), 10(5), and 5 x 10(6) images. The speed of the method depends on the size of the database and the number of clusters. The first stage of seed generation is close to linear for databases sizes up to approximately 2(34) approximately 10(10) images. On a single 2.4 GHz PC, the clustering process took only 24 minutes for a standard database of more than 100,000 images, i.e., only 0.014 seconds per image.
Effectiveness of Combination of Losartan Potassium and Doxycycline Versus Single-drug Treatments in the Secondary Prevention of Thoracic Aortic Aneurysm in Marfan Syndrome
The Journal of Thoracic and Cardiovascular Surgery. Aug, 2010 | Pubmed ID: 20189193
Losartan potassium (INN losartan), an antihypertensive drug, has been shown to prevent thoracic aortic aneurysm in Marfan syndrome through the inhibition of transforming growth factor beta. Recently we reported that doxycycline, a nonspecific inhibitor of matrix metalloproteinases 2 and 9, normalized aortic vasomotor function and suppressed aneurysm growth. We hypothesized that a combination of losartan potassium and doxycycline would offer better secondary prevention treatment than would single-drug therapy to manage thoracic aortic aneurysm.
Arterial Stiffness and Functional Properties in Chronic Kidney Disease Patients on Different Dialysis Modalities: an Exploratory Study
Nephrology, Dialysis, Transplantation : Official Publication of the European Dialysis and Transplant Association - European Renal Association. Dec, 2010 | Pubmed ID: 20466676
Abnormalities of vascular function and accumulation of oxidative stress have been associated with chronic kidney disease (CKD). Dialysis modalities, peritoneal dialysis (PD) and haemodialysis (HD) may differentially impact on vascular function and oxidative stress.
Creation and Validation of a Visual Macroscopic Hematuria Scale for Optimal Communication and an Objective Hematuria Index
The Journal of Urology. Jul, 2010 | Pubmed ID: 20478586
Macroscopic hematuria is a common symptom and sign that is challenging to quantify and describe. The degree of hematuria communicated is variable due to health worker experience combined with lack of a reliable grading tool. We produced a reliable, standardized visual scale to describe hematuria severity. Our secondary aim was to validate a new laboratory test to quantify hemoglobin in hematuria specimens.
Differential Microvasculature Dysfunction in Living Kidney Donor Transplant Recipients: Nondialyzed Versus Dialyzed Chronic Kidney Disease Patients
Journal of Vascular Research. 2010 | Pubmed ID: 19729959
We hypothesized that there was differential vasomotor dysfunction in the microcirculation between nondialyzed and dialyzed chronic kidney disease (CKD) patients. During live donor kidney transplantation procedures, skin arterioles (SkA; internal diameter = 120 +/- 5 microm) from donors (n = 27) and recipients (nondialysis = 15; dialysis = 20) were dissected from the abdominal wall at the incision site. In vivo aortic pulse wave velocity (PWV) was also measured. In the in vitro isometric force measurement, nondialyzed SkA exhibited comparable contraction to donor SkA, whereas dialyzed SkA had 60 and 40-50% increase in contraction in response to depolarization and agonist (that is, phenylephrine, serotonin and endothelin-1) stimulation, respectively. The acetylcholine-induced relaxation in the nondialyzed SkA was decreased by 50% compared with dialyzed SkA. However, pre-incubation with superoxide dismutase greatly enhanced the relaxation response in the nondialyzed, but not in the dialyzed SkA and donor SkA. Pre-incubation with N(G)-nitro-L-arginine methyl ester (L-NAME) elevated the resting tension and left-shifted the concentration response curve of phenylephrine-stimulated contraction in the donor-SkA. L-NAME only increased the resting tension in the nondialyzed vessel. In vitro stiffness positively correlated with PWV (R(2) = 0.302, p = 0.001), and dialyzed SkA was 60% stiffer than nondialyzed and donor SkA. The acetylcholine relaxation was negatively correlated with PWV in donors and recipients (R(2) = 0.282, p = 0.01). In conclusion, we have uniquely demonstrated differential microvasculature dysfunction between nondialyzed and dialyzed CKD patients.
Cataloging and Profiling Genes Expressed in Lentinula Edodes Fruiting Body by Massive CDNA Pyrosequencing and LongSAGE
Fungal Genetics and Biology : FG & B. Apr, 2011 | Pubmed ID: 21281728
This study investigated the molecular mechanism of the fruiting body development and sporulation in the cap of the Shiitake mushroom, Lentinula edodes. Although there has been much research into L. edodes, there remain significant gaps in our knowledge of how the species reproduces. In order to provide molecular resources and to understand the molecular mechanism of the fruiting body development in basidiomycete comprehensively, we searched for the genes which are important for fruiting body development and sporulation in the cap of mature fruiting body of L. edodes by using the whole-genome approach. Massive cDNA pyrosequencing was used to generate >7000 sequence contigs from mature fruiting bodies. We used Gene Ontology to categorize the contigs to form the catalog of genes expressed at the stage of the mature fruiting body. We also assigned the contigs into the KEGG pathways. The catalog of expressed genes indicates that the mature fruiting bodies (1) sense the external environment, (2) transmit signals to express genes through regulatory systems, (3) produce many proteins, (4) degrade unwanted proteins, (5) perform extensive biosynthesis, (6) generate energy, (7) regulate the internal environment, (8) transport molecules, (9) carry out cell division, and (10) differentiate and develop. After establishing the catalog of expressed genes in L. edodes, we used the LongSAGE approach to analyze the expression levels of genes found in mature fruiting bodies before (FB) and after (FBS) spores appeared. Gene-expression patterns according to GO categories were similar in these two stages. We have also successfully identified genes differentially expressed in FB and FBS. Fold-changes in expression levels of selected genes based on LongSAGE tag counts were similar to those obtained by real-time RT-PCR. The consistency between real-time RT-PCR and LongSAGE results indicates reliability of the LongSAGE results. Overall, this study provides valuable information on the fruiting processes of L. edodes through a combination of massive cDNA pyrosequencing and LongSAGE sequencing, and the knowledge thereby obtained may provide insight into the improvement of the yield of commercially grown Shiitake mushrooms.
A Novel Adoptive Transfer Model of Chronic Lymphocytic Leukemia Suggests a Key Role for T Lymphocytes in the Disease
Blood. May, 2011 | Pubmed ID: 21385850
Chronic lymphocytic leukemia (CLL) is an incurable adult disease of unknown etiology. Understanding the biology of CLL cells, particularly cell maturation and growth in vivo, has been impeded by lack of a reproducible adoptive transfer model. We report a simple, reproducible system in which primary CLL cells proliferate in nonobese diabetes/severe combined immunodeficiency/γc(null) mice under the influence of activated CLL-derived T lymphocytes. By co-transferring autologous T lymphocytes, activated in vivo by alloantigens, the survival and growth of primary CFSE-labeled CLL cells in vivo is achieved and quantified. Using this approach, we have identified key roles for CD4(+) T cells in CLL expansion, a direct link between CD38 expression by leukemic B cells and their activation, and support for CLL cells preferentially proliferating in secondary lymphoid tissues. The model should simplify analyzing kinetics of CLL cells in vivo, deciphering involvement of nonleukemic elements and nongenetic factors promoting CLL cell growth, identifying and characterizing potential leukemic stem cells, and permitting preclinical studies of novel therapeutics. Because autologous activated T lymphocytes are 2-edged swords, generating unwanted graph-versus-host and possibly autologous antitumor reactions, the model may also facilitate analyses of T-cell populations involved in immune surveillance relevant to hematopoietic transplantation and tumor cytoxicity.
Policy Implications of Neighbourhood Effects on Health Research: Towards an Alternative to Poverty Deconcentration
Health & Place. Sep, 2011 | Pubmed ID: 21696994
While researchers build an evidence that where one lives has an independent effect on their health, the work of translating this research into effective policies is impeded by problematic assumptions about urban poverty. In light of new experimental studies on the health effects of neighbourhoods using housing mobility programs, this paper addresses the politics of poverty deconcentration that implicitly undergirds much of this new research. By raising critiques of these programs that are rarely considered in the health literature, this paper challenges the central treatment of poverty dispersal in the new experimental literature. Poverty dispersal policies, without addressing the competitive urban structure, simply react to symptoms of poverty and ignore the underlying factors that shape the neighbourhood resources that structure health outcomes. These factors include municipal fragmentation, exclusionary land use planning, and municipal competition. Effective social policies aimed at improving neighbourhood influence on health must address the competitive and fragmented municipal structure that produces a patchwork of affluence and deprivation in today's urban America.
The Journal of Neuroscience : the Official Journal of the Society for Neuroscience. Aug, 2011 | Pubmed ID: 21813700
While oxidative stress has been implicated in small-fiber painful peripheral neuropathies, antioxidants are only partially effective to treat patients. We have tested the hypothesis that Drp1 (dynamin-related protein 1), a GTPase that catalyzes the process of mitochondrial fission, which is a mechanism central for the effect and production of reactive oxygen species (ROS), plays a central role in these neuropathic pain syndromes. Intrathecal administration of oligodeoxynucleotide antisense against Drp1 produced a decrease in its expression in peripheral nerve and markedly attenuated neuropathic mechanical hyperalgesia caused by HIV/AIDS antiretroviral [ddC (2',3'-dideoxycytidine)] and anticancer (oxaliplatin) chemotherapy in male Sprague Dawley rats. To confirm the role of Drp1 in these models of neuropathic pain, as well as to demonstrate its contribution at the site of sensory transduction, we injected a highly selective Drp1 inhibitor, mdivi-1, at the site of nociceptive testing on the dorsum of the rat's hindpaw. mdivi-1 attenuated both forms of neuropathic pain. To evaluate the role of Drp1 in hyperalgesia induced by ROS, we demonstrated that intradermal hydrogen peroxide produced dose-dependent hyperalgesia that was inhibited by mdivi-1. Finally, mechanical hyperalgesia induced by diverse pronociceptive mediators involved in inflammatory and neuropathic pain-tumor necrosis factor α, glial-derived neurotrophic factor, and nitric oxide-was also inhibited by mdivi-1. These studies provide support for a substantial role of mitochondrial fission in preclinical models of inflammatory and neuropathic pain.
Journal of Neurosurgery. Pediatrics. Nov, 2011 | Pubmed ID: 22044381
Attacks on humans by large cats are uncommon occurrences and thus the principles of managing such injuries are not well documented. The authors here report the case of an 11-year-old boy who was mauled by a privately owned tiger. The attack resulted in multiple cranial lacerations and fractures, dissection of the internal carotid artery, and persistent neurological deficits. This case outlines the multiple sources of injury and pathology that can result from such an attack. Discussion is focused on the pattern of injury seen in large feline attacks and the treatment approach.
The Annals of Otology, Rhinology, and Laryngology. Nov, 2011 | Pubmed ID: 22224318
Electromyographic studies of the laryngeal adductor reflex, glottal closure occurring in response to laryngeal stimulation, have demonstrated an early ipsilateral response (R1) and a late bilateral response (R2). To better define the physiologic properties of these responses, we recorded responses from expiratory laryngeal motoneurons (ELMs) in rats during stimulation of the superior laryngeal nerve (SLN).
Nano Letters. Mar, 2012 | Pubmed ID: 22375712
Photolithography is the technology of choice for mass patterning in semiconductor and data storage industries. Superlenses have demonstrated the capability of subdiffraction-limit imaging and been envisioned as a promising technology for potential nanophotolithography. Unfortunately, subdiffraction-limit patterns generated by current superlenses exhibited poor profile depth far below the requirement for photolithography. Here, we report an experimental demonstration of sub-50 nm resolution nanophotolithography via a smooth silver superlens with a high aspect profile of ~45 nm, as well as grayscale subdiffraction-limit three-dimensional nanopatterning. Theoretical analysis and simulation show that smooth interfaces play a critical role. Superlens-based lithography can be integrated with conventional UV photolithography systems to endow them with the capability of nanophotolithography, which could provide a cost-effective approach for large scale and rapid nanopatterning.