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Biomedical subjects

P Kumar

Publications and source records attributed to P Kumar.

At least 631 records · Page 35Linked to original sources

Mammalian alpha-polymerase: cloning of partial complementary DNA and immunobinding of catalytic subunit in crude homogenate protein blots.

A new polyclonal antibody against the alpha-polymerase catalytic polypeptide was prepared by using homogeneous HeLa cell alpha-polymerase. The antibody neutralized alpha-polymerase activity and was strong and specific for the alpha-polymerase catalytic polypeptide (Mr 183,000) in Western blot analysis of crude extracts of HeLa cells. The antibody was used to screen a cDNA library of newborn rat brain poly(A+) RNA in lambda gt11. A positive phage was identified and plaque purified. This phage, designated lambda pol alpha 1.2, also was found to be positive with an antibody against Drosophila alpha-polymerase. The insert in lambda pol alpha 1.2 (1183 base pairs) contained a poly(A) sequence at the 3' terminus and a short in-phase open reading frame at the 5' terminus. A synthetic oligopeptide (eight amino acids) corresponding to the open reading frame was used to raise antiserum in rabbits. Antibody affinity purified from this serum was found to be immunoreactive against purified alpha-polymerase by enzyme-linked immunosorbent assay and was capable of immunoprecipitating alpha-polymerase. This indicated the lambda pol alpha 1.2 insert encoded an alpha-polymerase epitope and suggested that the cDNA corresponded to an alpha-polymerase mRNA. This was confirmed in hybrid selection experiments using pUC9 containing the cDNA insert and poly(A+) RNA from newborn rat brain; the insert hybridized to mRNA capable of encoding alpha-polymerase catalytic polypeptides. Northern blot analysis of rat brain poly(A+) RNA revealed that this mRNA is approximately 5.4 kilobases.

Amino Acid Sequence↗

Evaluation of desmin as a diagnostic and prognostic marker of childhood rhabdomyosarcomas and embryonal sarcomas.

The diagnostic and prognostic relevance of desmin expression in 80 rhabdomyosarcomas (RMS) and 5 embryonal sarcomas (ES) was examined using a peroxidase anti-peroxidase staining procedure. Fifty-nine RMS but only one ES stained for desmin (P less than 0.05). The maximum percentage of desmin containing cells was 49 in RMS compared with only 1% in ES. Desmin positivity correlated inversely with survival (P less than 0.02) in that RMS with high proportions of desmin positive cells were associated with poorer prognoses than those containing fewer desmin positive cells. If the degree of expression of desmin is related to myogenic differentiation, then our results indicate that poorly differentiated RMS tend to have a better prognosis than the well differentiated tumours. One possible explanation is that the poorly differentiated RMS respond better to chemotherapy than to well differentiated RMS. A multivariant analysis incorporating desmin staining, treatment, histology, age and gender revealed that the two most significant independent prognostic factors were treatment and histology.

Desmin↗

Sebaceous gland hyperplasia and senile comedones: a prevalence study in elderly hospitalized patients.

Two hundred and eighty-six patients over the age of 65 (age range 65-102, mean age 82 years), who were hospitalized in geriatric wards, were examined clinically for the presence of sebaceous gland hyperplasia and senile comedones. The degree of solar elastotic change present was scored on a visual analogue scale. The prevalence rate of sebaceous gland hyperplasia and of senile comedones was found to be 26% in each case. Approximately one third of patients had both lesions. Neither of these lesions was related to either the degree of solar elastotic change or the skin type with regard to tanning ability. It was concluded that chronic solar exposure was not a likely cause of these common conditions.

Acne Vulgaris↗

Study of childhood renal tumours using a monoclonal antibody to Tamm-Horsfall protein.

A monoclonal antibody to Tamm-Horsfall glycoprotein was used for the immuno-localization of Tamm-Horsfall protein in formalin fixed, paraffin embedded tissue sections of childhood renal tumours, normal children's kidneys, and human fetal kidneys. The procedure was a dinitrophenyl hapten sandwich staining method. The antibody, diluted 1/100,000, gave a very strong and specific staining of the loop of Henle and distal tubules of normal and fetal kidneys. No staining was seen in Wilms' tumour, mesoblastic nephroma, and bone metastasizing renal tumour of childhood. In contrast, two of seven renal carcinomas and three of four rhabdoid renal tumours were positive for Tamm-Horsfall protein.

Antibodies, Monoclonal↗

HLA class II alpha chain gene polymorphisms in patients with insulin-dependent diabetes mellitus, dermatitis herpetiformis, and celiac disease.

We have investigated DNA polymorphism of the class II alpha chain genes in HLA typed patients with insulin dependent diabetes mellitus (IDDM; n = 79), celiac disease (CD; n = 46), dermatitis herpetiformis (DH; n = 53), and controls (n = 86). Preferential allelic associations of HLA genes and gene products have thus been constructed for susceptibility to these diseases. DR alpha and DQ alpha gene polymorphisms indicated heterogeneity of HLA DR3, DRw6, and DR7, and HLA DR2 and DRw6, respectively. In DR7 positive CD patients a 3.8-kilobase (kb) DR alpha fragment, which correlated with DQw3, was found in only 11% of patients compared with 45% of corresponding controls (P less than 0.05). An increased frequency of a DX alpha genotype UU in all three diseases was found (IDDM 59%, DH 45%, CD 48%, compared to 21% in controls, P less than 0.001), which is not explained solely by the increased frequencies of DR3-DX alpha U. We therefore conclude part of the genetic susceptibility for these three conditions is encoded by genes within the DQ-DX subregion.

Celiac Disease↗