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Biomedical subjects

A Chakravarti

Publications and source records attributed to A Chakravarti.

At least 19 recordsLinked to original sources
PubMed2006

Distribution of hepatitis C virus genotypes in beta-thalassaemic patients from Northern India.

Multitransfused beta-thalassaemic patients constitute a population having a higher prevalence of hepatitis C virus (HCV) infection because of its transmission from infected blood collected during seronegative window period. HCV genotyping in thalassaemic patients is mainly useful for the clinical management of the patients and for facilitating decisions on therapy. Thus, the aim of the present study was to identify the genotypes that are prevalent in thalassaemic patients and to correlate these with gender, age, number of blood transfusions and the liver function test profiles. Reverse transcription-polymerase chain reaction (RT-PCR) was carried out in 80 beta-thalassaemic patients (58 men and 22 women) for detection of HCV RNA who were seronegative for hepatitis B virus or human immunodeficiency virus antibodies. HCV genotyping was carried out by restriction fragment length polymorphism (RFLP) method of Chinchai et al. Type-specific PCR followed by direct sequencing was also used to confirm the mixed-genotype infection. Among the 80 thalassaemic patients, 20 and eight patients were infected with genotypes 3 and 1, respectively, whereas two cases had infection with HCV genotype1c/5a. The serum levels of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase were found to be significantly altered between the two groups of HCV-infected and noninfected thalassaemic patients. No significant correlation was observed between genotypes when compared with gender, age and number of blood transfusions, except significantly higher level of ALP in genotype 1 than in genotype 3. Genotype 3 alone was the predominant type in beta-thalassaemic patients, with approximately 45% being infected with mixed type. Hence, detection of HCV RNA would help in decreasing the transmission of HCV-infected blood collected during the seronegative window period, whereas determination of genotypes would provide help in adoption of different treatment policies for better management of thalassaemic patients.

Adolescent↗
PubMed2005

Hepatitis B vaccine in the EPI schedule.

OBJECTIVE: This study was carried out to evaluate the adequacy of seroconversion when Hepatitis B vaccine is given along with other vaccines at 0, 6 weeks (along with DPT and OPV) and at 9 months (along with measles). METHODS: 725 infants born to apparently healthy mothers were enrolled to receive the hepatitis B vaccine at 0, 6 weeks and 9 months (Group A) or at 0, 1 and 6 months as per WHO schedule--(Group B). Baseline HbsAg testing was carried out and the babies were immunized with the first dose of hepatitis B vaccine within 48 hours of birth. BCG and the other EPI vaccines were given as per schedule. Serum samples were collected 4 weeks after the second and the third immunizations. 604 infants (83.3%) completed the study. The testing for HbsAg and Anti Hbs titers were conducted in the Department of Microbiology, Maulana Azad Medical College, New Delhi utilizing standard ELISA kits. RESULTS: The seroconversion rates 4 weeks after the second dose of the vaccine were 90.89% (GMT = 48.23) and 91.82% (GMT = 43.95) (P=0.8) in Group A and Group B respectively. After 4 weeks of the third dose the seroconversion rates were 98.99 (GMT = 161.12) and 98.45 (GMT = 150.12) (p=0.17) in Group A and Group B respectively. The two schedules were comparable on using the Kruskal-Wallis H method for analysis. CONCLUSION: The schedule of hepatitis B vaccination at 0, 6 weeks and 9 months has the same seroefficacy as the currently recommended schedule of 0, 1 and 6 months.

Hepatitis B↗
PubMed2005

IL-6 gene variation is not associated with increased serum levels of IL-6, muscle, weakness, or frailty in older women.

Elevated levels of the inflammatory cytokine IL-6 are associated with the development of disability, frailty, and mortality in older adults. These outcomes are likely mediated through inflammatory activity that alters hormones, skeletal muscle, and the immune system. Polymorphic variants in the IL-6 gene influence IL-6 expression. We hypothesized that IL-6 alleles associate with increased serum of IL-6, decreased muscle strength, and frailty, and tested this in the Women's Health and Aging cohorts. We genotyped 463 participants age 70-79, and identified three common IL-6 haplotype blocks for the Caucasian (n=363) and African American (n=100) subsets. Using linear and logistic regression, and adjusting for age, BMI, race, and osteoarthritis, we identified no significant or clinically meaningful relationship between any single IL-6 single nucleotide polymorphism (SNP) or any IL-6 haplotype and serum IL-6 level, grip, knee, or hip strength, or frailty. Given that the promoter SNP (rs1800795) has been reported to influence IL-6 levels and health outcomes, we performed a similar association study in the In Chianti population (n=266) and confirmed lack of association. These results suggest that IL-6 gene variation may not be an important factor in the determination of elevated IL-6 levels and related phenotypes found in older women.

Aged↗
PubMed2005

Removal of catheter at midnight versus early morning: the patients' perspective.

BACKGROUND: With an increasing role of the patient as a partner in making a combined decision in care plan goals, it is important to identify the patient's perspective of the experience of removal of catheter (ROC). METHODS: A non-consecutive prospective randomized study was performed in 84 patients who underwent a transurethral resection of the prostate to determine the impact of midnight versus early-morning ROC on sleep deprivation, over all discomfort to the patient. RESULTS: There was no difference in the patient experience in both groups. We found a reduced frequency during the first 6 h of ROC at midnight. However, there was an increased incidence of sleep disturbances in this group. This may in part be due to an anxiety of urge incontinence and may be allayed by appropriate counselling. There was no delay in discharge of the patients in both groups. CONCLUSION: The patients must, therefore, be given the choice of ROC either at midnight or early morning, as the advantages of a reduced frequency must be correlated with an increased incidence of sleep disturbances.

Aged↗
PubMed2005

A study on the perinatal transmission of the hepatitis B virus.

The purpose of this study was to determine the age wise prevalence of Hepatitis B virus (HBV) in children under five years and to analyze the relative importance of horizontal or vertical transmission. This study included 400 children in the age group of less than five years attending the outpatient department of pediatrics with minor complaints. History of HBV immunization was taken as the exclusion criteria. All the samples were tested for Hepatitis B surface antigen (HBsAg) and anti HBs using commercial ELISA kits. Liver function tests were performed on all the HBsAg positive patients. Hepatits B nucleocapsid antigen (HBeAg) was detected in few HBsAg positive mothers. Overall HBsAg positivity in children below five years was 2.25%. There was no statistically significant difference in HBsAg positivity in the different age groups by chi square test. HBsAg positivity in mothers was 4.25%. However only in three cases the pair of mother and child were both positive for HBsAg. The mean anti HBs positivity in children was 23.75%. There was no statistically significant difference in the anti HBs positivity in different age groups of children. The observation that there is no statistically significant difference in the prevalence of HBV infection (HBsAg and HBs) amongst different age groups of children below five years signifies that a large proportion of HBV infection in children of this age is acquired via vertical transmission. It is also indicated that this mode of disease transmission is responsible for the majority of chronic carriers. Universal immunization of all infants is desirable to decrease the carrier pool and it is inferred from the present study that Hepatitis B immunization should begin at birth to have greater impact.

Child, Preschool↗
PubMed2005

Anti-HCV seropositivity among multiple transfused patients with beta thalassaemia.

Hepatitis C virus is considered to be the main aetiological agent responsible for the occurrence of post-transfusion hepatitis. Patients with thalassaemia acquire hepatitis most often from viruses contracted through blood transfusions. The present study was undertaken to evaluate the prevalence of hepatitis C virus (HCV) in thalassaemic patients with multiple blood transfusions. The association of HCV seropositivity with number of blood transfusions and liver enzyme profile was also analysed. The study group consisted of fifty patients (40 males and 10 females) attending the thalassaemic unit of Lok Nayak Hospital, a tertiary care hospital at Delhi, within the age group of 1-25 years. Thirty patients (60%) were found to be seropositive for HCV antibodies while one patient (2%) was co-infected with HCV antibodies and hepatitis B surface antigen. Study of liver enzyme profile showed aspartate aminotransferase levels to be significantly higher, although the level of serum alanine aminotransferase, alkaline phosphatase, total protein, bilirubin and albumin were not significantly altered in these patients. It is inferred from this study that 60% of the thalassaemics were infected with HCV and this was directly related to the number of blood transfusions received by them. The regularised national blood policy followed by blood banks for providing safe blood along with better screening method of donated blood in blood banks would bring down the incidence of hepatitis C in such high risk group.

Blood Transfusion↗
PubMed2003

Loss of p16 expression is of prognostic significance in locally advanced prostate cancer: an analysis from the Radiation Therapy Oncology Group protocol 86-10.

PURPOSE: The retinoblastoma (RB) cell cycle regulatory pathway is known to be deregulated in virtually all known human tumors. The protein product of the RB gene, pRB, and its upstream regulator, p16, are among the most commonly affected members of this pathway. We investigated the prognostic significance of both pRB and p16 expression in locally advanced prostate cancers, from patients treated on the Radiation Therapy Oncology Group (RTOG) protocol 86-10. MATERIALS AND METHODS: Sixty-seven cases from RTOG 86-10 had immunohistochemically stained slides, judged interpretable for both p16 and pRB, available for analysis. Median follow-up was 8.9 years (range, 6.0 to 11.8 years) for surviving patients. Staining for each marker was then correlated with overall survival, local progression, distant metastasis, and disease-specific survival. RESULTS: Loss of p16 expression, as defined by expression was significantly associated with reduced overall survival (P =.039), disease-specific survival (P =.006), and higher risk of local progression (P =.0007) and distant metastasis (P =.026) in the univariate analysis. In the multivariate analysis, loss of p16 was significantly associated with reduced disease-specific survival (P =.0078) and increased risk of local failure (P =.0035) and distant metastasis (P =.026). A borderline association with reduced overall survival (P =.07) was also evident. Loss of pRB was associated with improved disease-specific survival on univariate (P =.028) and multivariate analysis (P =.043), but carried no other significant outcome associations. CONCLUSION: Loss of p16 is significantly associated with adverse clinical outcome in cases of locally advanced prostate cancer.

Adult↗
PubMed2003

Comparative analyses of multi-species sequences from targeted genomic regions.

The systematic comparison of genomic sequences from different organisms represents a central focus of contemporary genome analysis. Comparative analyses of vertebrate sequences can identify coding and conserved non-coding regions, including regulatory elements, and provide insight into the forces that have rendered modern-day genomes. As a complement to whole-genome sequencing efforts, we are sequencing and comparing targeted genomic regions in multiple, evolutionarily diverse vertebrates. Here we report the generation and analysis of over 12 megabases (Mb) of sequence from 12 species, all derived from the genomic region orthologous to a segment of about 1.8 Mb on human chromosome 7 containing ten genes, including the gene mutated in cystic fibrosis. These sequences show conservation reflecting both functional constraints and the neutral mutational events that shaped this genomic region. In particular, we identify substantial numbers of conserved non-coding segments beyond those previously identified experimentally, most of which are not detectable by pair-wise sequence comparisons alone. Analysis of transposable element insertions highlights the variation in genome dynamics among these species and confirms the placement of rodents as a sister group to the primates.

Animals↗
PubMed2003

Whole blood samples as an alternative to serum for detection of immunity to measles virus by ELISA.

The aim of this study was to evaluate enzyme linked immunosorbent assay (ELISA) as a testing strategy for detection of antibodies against measles virus from microquantities of blood soaked onto filter paper. We studied 165 healthy children in the age group of 1 to 2 years, attending the outpatient department of pediatrics. Two sets of samples were collected from each child. One by venipuncture and the other on Whatman filter paper-3 discs of 20 mm size by finger or heel prick so that each strip is completely soaked with blood on both sides. These were tested for measles virus antibodies by ELISA using Melotest measles IgG commercial ELISA kit manufactured by Melotec S. A. (Barcelona, Spain). The resulting sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the filter paper (FP) ELISA compared to serum ELISA was 100, 90, 97.8, and 100%, respectively. The correlation coefficient r = 0.93% (p < 0.001) and the agreement between the two techniques was 98% as calculated by the Kappa statistical method. The present study has found filter paper testing by ELISA to be a promising qualitative technique for detection of immunity against measles.

Antibodies, Viral↗
PubMed2001

Testing for colon neoplasia susceptibility variants at the human COX2 locus.

BACKGROUND: Siblings and other first-degree relatives of patients with "sporadic" (i.e., apparently nonfamilial) colorectal cancer or precursor adenomatous colon polyps have an increased risk of developing colon neoplasia. This observation suggests the presence of inherited genetic determinants for sporadic colon neoplasia. Mice homozygous for a null cyclooxygenase 2 (COX2) (also called PTGS2) allele have a dramatically reduced susceptibility to the development of intestinal adenomas. In humans, use of pharmacologic inhibitors of COX2 enzyme activity are associated with reduced risk of colon neoplasia. This study examined whether the human COX2 locus may be linked to colon neoplasia in humans. METHODS: We used the affected sibling-pair method to test for linkage of the human COX2 locus to colon neoplasia. RESULTS: We examined 74 concordantly affected sibling pairs from 46 sibships with colon neoplasia. One hundred five siblings from these sibships were diagnosed with either colorectal cancer or colon adenomatous polyps before age 65 years. No linkage between COX2 and colon neoplasia was found by use of a multipoint model-free linkage analysis (estimate of allele sharing was 0.44; standard error = +/-0.04; 95% confidence interval = 0.36 to 0.52). Moreover, even allowing for heterogeneity, the potential that a COX2 colon neoplasia susceptibility variant was present within a substantial subset of these sibships was strongly excluded under either a recessive or a dominant inheritance model (95% confidence to exclude a model in which 2.7% or more of the sibling pairs harbor a dominant susceptibility allele). CONCLUSIONS: This study of concordantly affected sibling pairs thus demonstrates that variations in the COX2 gene are unlikely to be a source of individual susceptibility to colon neoplasia in humans.

Adenomatous Polyposis Coli↗
PubMed2001

The winged helix/forkhead transcription factor Foxq1 regulates differentiation of hair in satin mice.

Satin (sa) homozygous mice have a silky coat with high sheen arising from structurally abnormal medulla cells and defects in differentiation of the hair shaft. We demonstrate that the winged helix/forkhead transcription factor, Foxq1 (Forkhead box, subclass q, member 1) is mutant in sa mice. An intragenic deletion was identified in the radiation-induced satin mutant of the SB/Le inbred strain; a second allele, identified by an N-ethyl-N-nitrosourea (ENU) mutagenesis screen, has a missense mutation in the conserved winged helix DNA-binding domain. Homozygous mutants of the two alleles are indistinguishable. We show that Foxq1 is expressed during embryogenesis and exhibits a tissue-restricted expression pattern in adult tissues. The hair defects appear to be restricted to the inner structures of the hair; consequently, Foxq1 has a unique and distinct function involved in differentiation and development of the hair shaft. Despite an otherwise healthy appearance, satin mice have been reported to exhibit suppressed NK-cell function and alloimmune cytotoxic T-cell function. We show instead that the immune defects are attributable to genetic background differences.

Amino Acid Sequence↗
PubMed2001

EDNRB/EDN3 and Hirschsprung disease type II.

The study of vertebrate pigmentary anomalies has greatly improved our understanding of melanocyte biology. One such disorder, Waardenburg syndrome (WS), is a mendelian trait characterized by hypopigmentation and sensorineural deafness. It is commonly subdivided into four types (WS1-4), defined by the presence or absence of additional symptoms. WS type 4 (WS4), or Shah-Waardenburg syndrome, is also known as Hirschsprung disease Type II (HSCR II) and is characterized by an absence of epidermal melanocytes and enteric ganglia. Mutations in the genes encoding the endothelin type-B receptor (EDNRB) and its physiological ligand endothelin 3 (EDN3) are now known to account for the majority of HSCR II patients. Null mutations in the mouse genes Ednrb and Edn3 have identified a key role for this pathway in the normal development of melanocytes and other neural crest-derived lineages. The pleiotropic effects of genes in this pathway, on melanocyte and enteric neuron development, have been clarified by the embryologic identification of their common neural crest (NC) ancestry. EDNRB and EDN3 are transiently expressed in crest-derived melanoblast and neuroblast precursors, and in the surrounding mesenchymal cells, respectively. The influence of EDNRB-mediated signaling on the emigration, migration, proliferation, and differentiation of melanocyte and enteric neuron precursors, in vivo and in vitro has recently been the subject of great scrutiny. A major emergent theme is that EDN3-induced signaling prevents the premature differentiation of melanocyte and enteric nervous system precursors and is essential between 10 and 12.5 days post-coitum. We review the present understanding of pigment cell development in the context of EDNRB/EDN3--a receptor-mediated pathway with pleiotropic effects.

Cell Differentiation↗