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Biomedical subjects

R C Gupta

Publications and source records attributed to R C Gupta.

At least 307 records · Page 17Linked to original sources
PubMed1981

Lack of a specific ribose methylation at guanosine 17 in Morris hepatoma 5123D tRNASer1IGA.

Tumor transfer RNA's (tRNA's) frequently exhibit alterations in column chromatographic profiles and in base compositions when compared to their normal counterparts. Because such alterations may be involved in the dedifferentiated state of cancer cells, it is of interest to determine their structural basis and functional significance. The recent development of highly sensitive postlabeling methods has now made possible sequence analysis of tRNA's from neoplastic tissues available only in limited amounts. We have determined the nucleotide sequence of Morris hepatoma serine tRNA (anticodon IGA) and compared it with its normal counterpart in rat liver. The tumor serine tRNA was found to lack the ribose methylation of guanosine in position 17 of the dihydrouridine loop present in the liver RNA. This result explains the column chromatographic shifts of Morris hepatoma 5123D seryl-tRNA isoacceptors, suggesting that all seryl-tRNA isoacceptors may lack this modification.

Animals↗
PubMed1981

Isolation of circulating immune complexes by conglutinin and separation of antigen from dissociated complexes by immobilized protein A.

A method for the isolation of complement-fixing immune complexes from human serum and the separation of antigen from antibody is described. In order to isolate the complexes, we used soluble bovine conglutinin in a three-step procedure: (1) serum containing immune complexes is reacted with conglutinin in the presence of 10 mM calcium; (2) the conglutinin-bound immune complexes are precipitated by anti-conglutinin rabbit serum; (3) the precipitate is washed and the complexes are eluted from the precipitate by EDTA (pH 7.5) which chelates calcium and releases C3-associated immune complexes from conglutinin. To separate the antigen from the antibody, the isolated complexes are acid-dissociated (pH 3.0), and the antibody is absorbed to staphylococcal protein A conjugated to Sepharose leaving the antigen in solution. The antibody bound to Sepharose-protein A is recovered by elution with 3.5 M magnesium chloride. This procedure permitted the isolation of immune complexes from sera of hepatitis B surface antigen (HBsAg) positive chronic active hepatitis. In addition, immune complexes were isolated from sera of patients with rheumatoid arthritis, systemic lupus erythematosus and primary biliary cirrhosis. The isolated immune complexes contained IgG, IgM, C3 and albumin. Specific antibodies such as rheumatoid factors, anti-nuclear antibodies and antimitochondrial antibodies in varying titres have been found to be present in the isolated immune complexes. The conglutinin method has proven to be a useful technique for the isolation of immune complexes and for the identification of antibody and could be applied to the identification of the antigen in immune complexes.

Antigen-Antibody Complex↗
PubMed1980

Isolation and sequence analysis of two major leucine transfer ribonucleic acids (anticodon Mm-A-A) from a rat tumor, Morris hepatoma 5123D.

The nucleotide sequences of two major tRNALeu species (anticodon Mn-A-A)isolated from Morris hepatoma 5123D were determined by a combination of a newly developed thin-layer readout sequencing method [Gupta, R. C., & Randerath, K. (1979) Nucleic Acids Res. 6, 3443-3458] and additional 3H- and 32P-labeled derivative methods entailing chromatographic fingerprinting and base-specific enzymatic cleavages. The nucleotide sequence of the two hepatoma tRNAMm-A-ALeu species, one of which has U and the other of which has A in position 50 at the tip of the long extra arm, is pG-U-C-A-G-m2G-A-U-G-(m2)G-C-(ac4)C-G-A-G-U-G-G-D-C-psi-A-A-G-G-C-m22G-C-C-A-G-A--C-U-Mm-A-A-m1G*-psi-psi-C-U-G-G-L-(psi)U-C-C-G-U- or A-A-U-G-G-A-G-m5C-G-U-G-G-G-T-psi-C-G-m1A-A-U-C-C-C-A-C-U-U-C-U-G-A-C-A-C-C-AOH. These are the first leucine tRNA sequences from higher eukaryotes that have been determined. Noteworthy features of the mammalian leucine tRNAs are the presence of psi in the beta region of the D loop and the occurrence of three unknown hypermodified nucleosides (Mm, m1G*, and L) in positions 35, 38, and 45, respectively. m1G* was converted to m1G by treatment with alkali. Sequencing gels indicated that the parent base of the 2'-O-methylated nucleoside Mm may be a pyrimidine, probably a C derivative, as indicated by the chromatographic behavior of nucleotides containing Mm. The presence of a pyrimidine in the wobble position would be consistent with the antidodon sequence Mm-A-A and the leucine condons U-U-G and U-U-A. The occurrence of a hypermodified nucleoside, L, in the first position of the long extra arm appears unusual; thus far the only modified nucleoside found in this position is Um in eukaryotic serine tRNAs. Since all tRNAs with a long extra arm sequenced to date have a pyrimidine in this position, L is likely to be a pyrimidine, probably a U derivative, as inferred from chromatographic data.

Animals↗
PubMed1980

Circulating immune complexes in giant cell arteritis and polymyalgia rheumatica.

Sera from 74 patients with polymyalgia rheumatica or giant cell arteritis or both were tested for immune complexes by using the Raji cell radioimmunoassay. Levels in patients with active disease were higher than in patients whose disease had become inactive. There was no difference in levels of immune complex-like materials between patients with polymyalgia rheumatica alone and those with giant cell arteritis. Density gradient analysis of one serum showed immune complex-like materials mainly in the 19S region. Immune complexes may be important in the pathogenesis of these conditions.

Aged↗
PubMed1980

Treatment of femoral diaphyseal fractures in children by strapping.

Sixty-three children with closed uncomplicated fractures of the shaft of the femur were treated by strapping the fractured thigh to the flexed leg by zinc oxide adhesive tape. Forty-eight patients with follow-up times of 6 months to 3 years were evaluated for final assessment. The result were good in 43 and fair in 5 children. The method is effective, safe and easy; it is performed in one stage and does not require anaesthesia.

Bandages↗
PubMed1980

A clinical evaluation of osteomedullography in diaphyseal fractures.

Twenty-seven cases with delayed union and nonunion were selected for the present study. Osteomedullograms were positive in 12 and negative in 15 cases. All the fractures with positive osteomedullograms united after conservative treatment. Fourteen of 15 fractures with negative osteomedullograms needed surgical treatment. Of 14, two are still in followup. One case with negative signs on osteomdeullogram refused surgery.

Adolescent↗
PubMed1980

Preciitating antibodies to mitochondrial antigens in patients with primary biliary cirrhosis.

Sera of patients with primary biliary cirrhosis (PBC) were examined for the presence of precipitating antibodies to sonicated rat liver mitochondrial (M) fraction. Three distinct precipitating systems observed in double immunodiffusion were identified and called M-A, M-B and M-C. Unsonicated mitochondria did not form precipitin lines. Precipitating system M-A was found in nineteen of twenty (95 percent) sera from PBC. The mitochondrial antigen of M-A system had the unusual property of being resistant to enzymatic digestion with deoxyribonuclease (DNase), ribonuclease (RNase) and trypsin under standard conditions. The titres of antibody to M-A antigen correlated (P less than 0.05) with titres of mitochondrial immunofluorescence staining on unfixed mouse kidney sections. Precipitating systems M-B and M-C were present in seven of twenty ribonuclease and trypsin but resistant to ribonuclease indicating that it could be DNA-protein complex. The M-C antigen was destroyed by trypsin suggesting its protein character, but it was difficult to determine if nucleic acids might also be associated with antigenicity. The antibodies to mitochondrial antigens were not present in normals (fifteen health adults), systemic lupus erythematosus (forty patients), rheumatoid arthritis (fifteen patients) and chronic liver diseases (fifteen patients). The antibodies did not show identity with antibodies to ribosomal ribonucleo-protein and other known nuclear antigens previously reported. The data confirm previous reports concerning the heterogeneity of mitochondrial antibodies present in sera of patients with PBC. The antibody to M-A antigen appeared to be a diagnostically useful immunological marker since it was present in the majority of patients with PBC.

Adult↗