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Biomedical subjects

U Kumar

Publications and source records attributed to U Kumar.

At least 73 records · Page 4Linked to original sources
PubMed1995

Hepatitis C virus type I(1a) in northern China.

Twenty-four patients with hepatitis C virus (HCV) antibody from the Chinese North Western province of Jilin were further analysed by the immunoblot assay-2 (RIBA-2), reverse transcription-polymerase chain reaction (RT-PCR) for serum HCV RNA detection, and direct sequence-genotyping. Good concordance was found between the original second generation HCV antibody ELISA, RIBA-2, and serum HCV RNA. The occurrence of genotype I (1a), a genotype not previously reported in China, is described in 5(20.8%) of 24 cases, in association with genotypes II(1b) and III(2a) which were found in 16(66.7%) and 3(12.5%) of 24 cases, respectively. Imported blood products were unlikely to be the source of infection with genotype I (1a) but could not be definitively ruled out.

Base Sequence↗
PubMed1995

Chronic hepatitis C virus infections: predictive value of genotype and level of viraemia on disease progression and response to interferon alpha.

The effects of hepatitis C virus genotype and viraemia on disease outcome in patients with chronic hepatitis C virus infection were studied. Patients infected with genotype 1 tended to develop more severe disease, and to respond less well to interferon (IFN) treatment, but no pretreatment variable successfully predicted either the severity of the disease or the response to IFN. Failure to eliminate the virus during the first three months of therapy, however, predicted a failure to derive long term benefit from the current IFN regime. Hence pretreatment variables cannot be used to determine whether individual patients will respond to IFN, but observations during the first three months of therapy can be used to decide which patients will not respond to prolonged therapy. In these patients consideration should be given to changing the IFN dosing regime or using alternative treatments.

Base Sequence↗
PubMed1995

Hepatitis C virus replication in hepatocellular carcinoma.

Hepatitis C virus (HCV) replication is reported in both tumour and non-tumour tissue in a case of hepatocellular carcinoma. Viral replication was established by showing the presence of minus strand HCV RNA by PCR amplification, after excluding residual reverse transcriptase activity of Taq polymerase. No minus strand was found in serum derived virion RNA. PCR amplified products from both tumour and non-tumour parenchyma were sequenced in the 5' non-coding region and shown to be identical. The genotype of this Indonesian patient was found to be 1b (or II), the most prevalent type in the Far East.

Base Sequence↗
PubMed1995

Family pathology and anorexia in the Indian context.

Frequent associations have been found between family interaction and anorectic behaviour. Family theorists have viewed anorexia as a manifestation of a dysfunctional family system. We report three families of cases of anorexia (one male and two female) where the symptom was a reflection of family pathology and was being maintained by it. The cases emphasize the need to assess families of anorectics in detail and view them in the cultural context of eating.

Adolescent↗
PubMed1995

Trash penis.

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Aortic Aneurysm, Abdominal↗
PubMed1994

Hypervariable region of hepatitis C virus envelope glycoprotein (E2/NS1) in an agammaglobulinemic patient.

In an agammaglobulinemic patient with chronic hepatitis C, a previously identified hypervariable region of the major envelope glycoprotein remained unchanged for 2.5 years. Serum-derived RNA amplified by reverse transcription-polymerase chain reaction was cloned in a bacterial vector, and a minimum of three independent clones were sequenced by dideoxy chain termination reaction. Comparison of consensus sequences from three different time points during the chronic phase of infection showed absolute homology at both amino acid and nucleotide levels. This finding provides support for the role of antibody selection in generating genetic variation and viral persistence; also, it is consistent with the hypothesis that an epitope within this region is the site of virus neutralization. The observations show that the hepatitis seen in hepatitis C virus infection is not dependent on the humoral immune response.

Agammaglobulinemia↗
PubMed1994

Mitochondria from Alzheimer's fibroblasts show decreased uptake of calcium and increased sensitivity to free radicals.

Many of the biological abnormalities seen in samples of the brain and other tissues from patients with Alzheimer's disease, are consistent with an excessive action of oxygenic free radicals. Mitochondria from fibroblasts grown in tissue culture from skin samples taken at autopsy from patients with histologically confirmed Alzheimer's disease, take up significantly less calcium than do fibroblast mitochondria from age matched non-demented controls. Following exposure to oxygenic free radicals generated by adding ferrous ions to the incubation mixture, calcium uptake is increased to a greater extent in Alzheimer's mitochondria than in controls. At the doses used, pretreatment with the lazaroid antioxidant drug U-74500A, or with the iron chelator deferoxamine, prevents the free radical induced increase in calcium uptake by control mitochondria, but provides only partial protection for Alzheimer's mitochondria. These observations suggest that Alzheimer's fibroblast mitochondria have impaired calcium transport processes and show increased sensitivity to oxygenic free radicals.

Adult↗
PubMed1994

Serum HCV RNA levels in chronic HCV hepatitis measured by quantitative PCR assay; correlation with serum AST.

A quantitative PCR assay is described for serum HCV RNA which is based on a recombinant competitive titrating RNA template. This template is derived from the 5' non-coding region of the genome and generates a shorter PCR product (93 bp) than that from the serum-derived wild type genomes (279) bp from the same sets of primers. By using this assay we have found serum HCV RNA concentrations ranging between 3.3 x 10(2) and 6.6 x 10(8) viral genomes/ml of serum in 15 samples from 10 different patients, 9 cases of chronic hepatitis and one case of fulminant hepatitis. Comparison of viraemias with serum transaminase levels has shown a good correlation for individual patients between these two parameters during chronic HCV hepatitis.

Adult↗
PubMed1994

Metalloporphyrin speciation by liquid chromatography and inductively coupled plasma-mass spectrometry.

Inductively coupled plasma-mass spectrometry is investigated for the detection of metalloporphyrins (cobalt protoporphyrin, hemin, and zinc protoporphyrin) separated by liquid chromatography. A Hypersil SAS C1 column with mobile phase containing 68% methanol at a pH of 4.5 is used. The detection limits obtained are in the nanogram range for cobalt and zinc protoporphyrins, whereas for hemin, detection limits are in the microgram range. The accuracy of the method is evaluated by determining zinc protoporphyrin from the whole blood of a lead-poisoned patient.

Chromatography, High Pressure Liquid↗
PubMed1994

The acute neurotoxic effect of beta-amyloid on mature cultures of rat hippocampal neurons is attenuated by the anti-oxidant U-78517F.

The neuropathological characteristics of Alzheimer's disease include the selective loss of neurons and the development of senile plaques and neurofibrillary tangles. These plaques and tangles are invariably associated with deposits of an insoluble protein, beta-amyloid, and the hypothesis that the beta-amyloid is responsible for the neuronal loss in Alzheimer's disease has received considerable support. The neurotoxic action of beta-amyloid has been demonstrated in primary cultures of cortical and hippocampal neurons and in PC-12 cells. The present study reports that the neurotoxicity of beta-amyloid is reduced by the antioxidant drug U-78517F. On the basis of this observation, we suggest that the neurotoxic effect of beta-amyloid is mediated by oxygen free radicals. The clinical use of antioxidant interventions may reduce neurodegeneration and the progression of the symptoms in patients with Alzheimer's disease.

Amyloid beta-Peptides↗
PubMed1993

Sequence variation in the large envelope glycoprotein (E2/NS1) of hepatitis C virus during chronic infection.

Sequence variation in the putative large surface glycoprotein (E2/NS1) of hepatitis C virus (HCV) was analyzed over 18 months in 4 patients with chronic relapsing non-A, non-B liver disease, of whom 2 were treated with lymphoblastoid interferon-alpha. Sequence analysis showed marked heterogeneity between isolates from different patients at the hypervariable region mapping to the amino-terminus of E2/NS1 (amino acid position, 386-411) and the extended sequence analyzed again confirmed the existence of two types, HCV1 and HCV2. Sequential nucleotide analysis of the hypervariable region over 1 year for each patient showed 0-9 amino acid changes, more common in the untreated than in the interferon-alpha-treated patients (3 and 9 vs. 1 and 0). Peaks of raised serum transaminases in individual patients showed no consistent association with mutations within this region. However, results do not exclude the possibility that viral persistence may be due to the emergence of "escape mutants" in the hypervariable region.

Adult↗
PubMed1993

Pendred's syndrome.

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Audiometry, Evoked Response↗
PubMed1992

Quantitative dot-blot assay for proteins using enhanced chemiluminescence.

A sensitive non-radioactive method for detection of specific proteins on Western blots is commercially available. The protein is immobilized on nitrocellulose membrane and immunolabelled with HRP-conjugated secondary antibody. HRP catalyzes the oxidation of luminol, a cyclic diacylhydrazide, resulting in the emission of light which is recorded on film. Using dot blot, we have shown that the signal generated by this system is proportional to the amount of protein loaded onto the membrane. Standard curves were linear (r2 greater than 0.95) over a 10-50-fold range. Linearity was also achieved with tissue extracts probed for a specific antigen. The sensitivity of the method is such that less than 10 fmol protein can be measured. The sensitivity and range are comparable to a previously reported dot-blotting assay based on the use of 125I-protein A, but the method does not require the handling of radioactive compounds. This method was used to estimate the level of chromogranin A in a mixture of proteins extracted from human brain.

Adrenal Glands↗