Dindagur Nagaraja

Plasma Proteome Database as a resource for proteomics research: 2014 update.

Plasma Proteome Database (PPD; http://www.plasmaproteomedatabase.org/) was initially described in the year 2005 as a part of Human Proteome Organization’s (HUPO’s) pilot initiative on Human Plasma Proteome Project. Since then, improvements in proteomic technologies and increased throughput have led to identification of a large number of novel plasma proteins. To keep up with this increase in data, we have significantly enriched the proteomic information in PPD. This database currently contains information on 10 546 proteins detected in serum/plasma of which 3784 have been reported in two or more studies. The latest version of the database also incorporates mass spectrometry-derived data including experimentally verified proteotypic peptides used for multiple reaction monitoring assays. Other novel features include published plasma/serum concentrations for 1278 proteins along with a separate category of plasma-derived extracellular vesicle proteins. As plasma proteins have become a major thrust in the field of biomarkers, we have enabled a batch-based query designated Plasma Proteome Explorer, which will permit the users in screening a list of proteins or peptides against known plasma proteins to assess novelty of their data set. We believe that PPD will facilitate both clinical and basic research by serving as a comprehensive reference of plasma proteins in humans and accelerate biomarker discovery and translation efforts.

Heart rate variability and outcome in acute severe stroke: role of power spectral analysis.

AbstractIntroduction: Heart rate variability (HRV) is a predictor of outcome in acute myocardial infarction and head trauma. Its efficacy in predicting outcome in stroke has not been well documented. Materials and Methods: Twenty-five patients (mean age 39 years) with acute stroke treated in a stroke intensive care unit were studied. Continuous echocardiogram recorded for a 1-hour period was digitized and stored for off-line analysis. Time and frequency domain HRV measures were derived for the filtered and rectified ECG data for each patient. Clinical and HRV profiles were compared among patients who died or survived. Results: At admission, 16 patients were comatose (Glasgow Coma score <9 at admission), 16 had focal weakness, and all had abnormal brain computed tomography. Of the 25 patients, 11 died, 10 had a poor outcome, and 4 had good outcome. Two variables—low-frequency (LF) spectral power and very low-frequency (VLF) spectral power—correlated with mortality. After adjustment for mechanical ventilation and vasopressor administration, LF, VLF, and Triangular index of RR interval (TINN) correlated with mortality. On multiple regression analysis weighted for mechanical ventilation and vasopressor administration, the eye-opening score on Glasgow Coma Scale and LF spectral power were factors that were independently predictive of mortality. Conclusion: HRV measurements are independent predictors of outcome in acute severe stroke.

Association of the functional KL-VS variant of Klotho gene with early-onset ischemic stroke

Genetic variants of Klotho have been reported to be associated with human longevity and atherosclerotic vascular events and risk factors. However, very few studies have explored their association with ischemic stroke. We hypothesized that the functional KL-VS and the exonic C1818T variants of Klotho gene may be associated with ischemic stroke in Indian population. We enrolled a total of 460 patients with ischemic stroke and 574 age- and gender-matched controls for the study. Genotyping was done by polymerase chain reaction and restriction fragment length polymorphism. Contrary to other Asian reports, KL-VS variant was polymorphic in our population, with a frequency distribution similar to that of Caucasians. The frequency distribution of the C1818T variant was similar to previously reports in Asians. A differential effect of age on association of Klotho KL-VS variant with ischemic stroke was observed. In subjects aged ≤40 years, the KL-VS homozygotes, 352FF and 352VV, had ~1.5-fold (OR=1.57; 95% CI: 1.02-2.40, p=0.038) and ~3-fold (OR=3.29; 95%CI: 1.02-10.56, p=0.046) higher risk of stroke compared to heterozygotes, whereas in the older group (aged >40 years) no significant association was observed. The C1818T variant was not associated with ischemic stroke. We conclude that KL-VS homozygosity could contribute to early-onset stroke in India. Larger studies in other ethnic populations are warranted to determine the role of these gene variants in the etiology of stroke occurring in the young.

Anticardiolipin antibodies in ischemic stroke in the young: Indian experience

Anticardiolipin antibodies (aCL) have been recognised as a marker for an increased risk of thrombosis. The prevalence of these antibodies in young Indian ischemic stroke population is not known. Our study establishes the prevalence of these antibodies and evaluates their clinical significance in 60 patients aged 40 years or less who presented with completed ischemic stroke. Immunoglobulin G and immunoglobulin M class antibodies to anticardiolipin were determined using a standardized enzyme-linked immunosorbent assay. The prevalence of these antibodies in stroke patients was 23% compared to 3.2% in the controls. All patients studied had no overt evidence of systemic lupus erythematosus or related autoimmune disorders. The aCL-positive stroke patients did not differ significantly from aCL-negative stroke patients with regard to demographic characteristics, risk factor profile, and radiological features. Prior transient ischemic attacks, ischemic retinopathy, and asymptomatic infection were more frequent in the aCL-positive group. The role of anticardiolipin antibodies as a disease marker for ischemic stroke is under-recognised in India and warrants further investigation.

Localized convexity subarachnoid haemorrhage - a sign of early cerebral venous sinus thrombosis

Background:  The diagnosis of cerebral venous sinus thrombosis (CVST) requires a high index of suspicion owing to the wide spectrum of clinical manifestations. Amongst the different presentations, radiological evidence of subarachnoid haemorrhage (SAH) often leads to diagnostic errors.

Screening for inborn errors of metabolism using automated electrospray tandem mass spectrometry: study in high-risk Indian population.

OBJECTIVES Tandem mass spectrometry is a major technological advance in the screening for inborn errors of metabolism. It has the advantage of sensitive and simultaneous multiple disease screening with minimal sample requirement. The diseases detected include aminoacidemias, fatty acid oxidation disorders, and organic acidemias. DESIGN AND METHODS Using automated electrospray tandem mass spectrometry we screened 3550, clinically selected, symptomatic children for inborn errors of metabolism by analyzing amino acids and acylcarnitines in dried blood filter-paper samples. RESULTS Among these, 113 (3.2%) children were identified with a metabolic disorder: 61 (54%) patients had amino acid disorders, 47 (41.6%) had organic acidemias, and 5 (4.4%) children had disorders of fatty acid oxidation. The diagnoses were further confirmed through clinical symptoms, and other biochemical studies. CONCLUSIONS These results show that inherited metabolic disorders are not rare in India, a rapidly developing country with a high birth rate and relatively frequent occurrence of consanguineous marriages.

Homocysteine, folate and vitamin B12 in puerperal cerebral venous thrombosis

BACKGROUND AND OBJECTIVE Hyperhomocysteinemia (hyper-Hcy) is a known risk factor for venous thrombosis, but few studies document the risk in puerperal cerebral venous thrombosis (CVT). Nutritional folate and vitamin B(12) deficiency can cause hyper-Hcy and pregnancy may contribute to this deficiency. We studied the association of plasma total homocysteine (tHcy), folate and vitamin B(12) levels with puerperal CVT through a case-control study. METHODS Sixty women with puerperal CVT and 64 healthy puerperal controls were recruited. Plasma fasting tHcy was estimated by high pressure liquid chromatography using coulometric electrochemical detection. Vitamin B(12) and folate were measured by radioimmunoassay. Risk of puerperal CVT was estimated for each of the three variables. RESULTS Adjusted odds ratio for the risk of puerperal CVT with hyper-Hcy (>90th percentile) was 10.8 (95% CI: 4.0-29.4; adjusted for vitamin B(12) and folate levels). Low folate and vitamin B(12) levels (<10th percentile) did not increase the risk for puerperal CVT. There was a significant inverse correlation between folate and tHcy levels (rho=-0.471, p<0.001). CONCLUSIONS Hyperhomocysteinemia is associated with an increased risk of puerperal CVT occurring in Indian women and low folate levels contribute significantly to hyper-Hcy. Regular antenatal folate and vitamin B(12) supplementation is likely to lower puerperal tHcy levels, but its clinical benefit needs to be tested by large therapeutic trials.

Homocysteine and Cerebral Stroke in Developing Countries

Two-thirds of stroke deaths worldwide occur in developing countries. The higher prevalence of undernutritional states and parasitic infestations in many of these countries could lead to vitamin B(12) and folate deficiencies. Hyperhomocysteinemia, a proxy measure for the nutritional status of B vitamins, has been reported in many developing countries and is found to be associated with nutrition-related low plasma folate and vitamin B(12). Several epidemiological observations have linked hyperhomocysteinemia to increased risk for stroke. The exact molecular mechanism by which homocysteine promotes atherothrombosis is not clear, although several possible roles have been suggested. Homocysteine is believed to cause atherogenesis and thrombogenesis via endothelial damage, focal vascular smooth muscle proliferation probably causing irregular vascular contraction, and coagulation abnormalities. Supplementation with the nutrient cofactors required for optimal functioning of the homocysteine metabolic pathways significantly impacts plasma homocysteine levels, and offers a new integrated possibility for prevention of stroke in the underdeveloped and rapidly developing countries.

Asymmetric dimethylarginine as a risk marker for early-onset ischemic stroke in Indian population.

BACKGROUND Asymmetric dimethylarginine (ADMA), a circulating endogenous inhibitor of nitric oxide synthase, has been associated with the pathogenesis of atherosclerosis. The present study was initiated to investigate the role of ADMA as a biomarker of risk for early-onset ischemic stroke. METHODS Plasma ADMA levels were measured in 201 ischemic stroke patients aged between 15 and 50 years and 217, age and gender-matched healthy controls, by high performance liquid chromatography using pre-column derivatization with O-phthaldialdehyde. RESULTS Patients with ischemic stroke had significantly higher plasma ADMA compared with the controls (1.49 vs. 0.97 μmol/l, p < 0.001). After adjustment for vascular risk factors, increased ADMA was associated with stroke (OR=1.55, 95% CI 1.25-1.92, p < 0.001). Univariate analysis showed that ADMA was significantly associated with age, alcohol, smoking, hypertension, diabetes mellitus, low serum HDL-cholesterol and homocysteine. By multiple stepwise linear regression analysis, diabetes, HDL-cholesterol and homocysteine were found to be independent determinants of plasma ADMA. CONCLUSIONS Increased plasma ADMA is associated with increased risk for ischemic stroke in the young. Diabetes mellitus, HDL-cholesterol and homocysteine are independent predictors of elevation in plasma ADMA concentration.

Janus kinase (JAK) 2 V617F mutation in Asian Indians with cerebral venous thrombosis and without overt myeloproliferative disorders

It is unclear whether the somatic JAK2V617F mutation, a marker for chronic myeloproliferative disorders (MPDs), is associated with cerebral venous thrombosis (CVT) in the absence of MPD. Our aim was to determine the prevalence and association of the JAK2V617F mutation among patients with CVT and without overt MPD. We investigated 372 CVT patients without features suggestive of MPD and 383 age- and gender-matched healthy controls, for the JAK2V617F mutation. Genotyping was done by polymerase chain reaction and restriction fragment length polymorphism. The heterozygous JAK2V617F mutation was present in 22 of 372 patients (5.9%) and 2 of 383 controls (0.5%). Logistic regression analysis showed this mutation to be an independent predictor of CVT after adjusting for the conventional risk factors (adjusted odds ratio: 5.47, 95% CI: 1.06-28.27, p=0.04). The mutation was more prevalent in men (p=0.005). Patients with JAK2V617F mutation were older (p=0.036), and had higher mean hemoglobin level (p<0.0001) than those without the mutation. Smokers with the mutation had 9.45-fold increased risk of CVT compared to non-smokers without the mutation (OR: 9.45, 95% CI: 1.17-76.02, p<0.0001). We conclude that the JAK2V617F mutation could contribute to increased risk of CVT in Indians. Larger studies in other ethnic populations are warranted before considering the inclusion of the JAK2V617F gene polymorphism into the routine diagnostic workup of CVT.