Biomedical subjects

R K Gupta

Publications and source records attributed to R K Gupta.

At least 631 records · Page 35Linked to original sources

PubMed1984

Effect of storage temperatures on opacity and total nitrogen content of cholera vaccine.

Fluid cholera vaccine was examined for its stability at 4-8 degrees C, 20-25 degrees C and 37 degrees C with regard to the number of organisms present and the total nitrogen content. Ten batches of fluid cholera vaccine manufactured at the Central Research Institute, Kasauli, India were taken for the study. The number of organisms was determined at weekly intervals for the first month and at monthly intervals for the next 11 months. The percentage loss in the number of organisms after one year averaged 6.5 at 4-8 degrees C, 20.6 at 20-25 degrees C and 21.5 at 37 degrees C. The maximum loss in number of organisms took place during the first six months at these temperatures, in the following six months the number of organisms remained almost constant even at 37 degrees C. The total nitrogen content of the vaccine remained virtually unaltered during the same period. From this study it was concluded that the number of organisms and the total nitrogen content does not reflect the antigenicity nor potency of the vaccine.

Cholera Vaccines↗

PubMed1984

The titration of tetanus antitoxin I. Factors affecting the sensitivity of the indirect haemagglutination test.

Various factors affecting the indirect HA test for the titration of tetanus antitoxin have been evaluated with a view to obtaining maximum sensitivity in tests using unfixed sheep erythrocytes and sheep erythrocytes fixed with glutaraldehyde, formaldehyde and pyruvic aldehyde. The optimal concentration of tannic acid has been found to be 1/40 000 for tanning both fixed and unfixed sheep erythrocytes. Tanned sheep erythrocytes sensitized with 50 Lf/ml of tetanus toxoid at pH 7.2 for one hour were the most sensitive. Although the optimal temperature of sensitization was found to be 56 degrees C, unfixed cells tended to clump and lyse at this temperature. Thus a temperature of 37 degrees C was used to sensitize unfixed sheep erythrocytes. Sheep erythrocytes from different animals and the final concentration of sensitized sheep erythrocytes both had great effects on sensitivity. A final concentration of 0.5% of sensitized sheep erythrocytes was found suitable as a compromise between sensitivity and readability. The loss of sensitivity of fixed and sensitized erythrocytes was investigated by storing these cells at 4-8 degrees C for six to nine months.

Animals↗

PubMed1984

The titration of tetanus antitoxin II. A comparative evaluation of the indirect haemagglutination and toxin neutralization tests.

Serum samples from 77 guinea pigs immunized against tetanus have been titrated for tetanus antitoxin by a standardized indirect haemagglutination (IHA) test and the conventional toxin neutralization (TN) test. These sera were titrated before and after treatment of the sera with 2-mercaptoethanol (2-ME) by the IHA test using unfixed sheep erythrocytes and erythrocytes fixed with glutaraldehyde, formaldehyde and pyruvic aldehyde. The titres of these sera obtained by IHA using unfixed and glutaraldehyde-fixed sheep erythrocytes before treatment of the sera with 2-ME were two to six times higher than the TN titres, whereas the IHA-titres using formaldehyde- and pyruvic aldehyde-fixed sheep erythrocytes were 10 times higher than the TN titres in some of the sera. There was no statistically significant difference between TN and IHA titres using unfixed and glutaraldehyde-fixed sheep erythrocytes after the treatment of the sera with 2-ME.

Animals↗

PubMed1984

The titration of tetanus antitoxin III. A comparative evaluation of indirect haemagglutination and toxin neutralization titres of human sera.

The tetanus antitoxin titres of 174 serum samples from healthy adults were determined by a standardization indirect haemagglutination test (IHA) and the conventional toxin neutralization (TN) test. The serum samples were titrated by the IHA test using glutaraldehyde-fixed and toxoid sensitized sheep erythrocytes before and after the treatment of the sera with 2-mercaptoethanol (2-ME). The IHA method has been found to be very sensitive and specific for the estimation of tetanus antitoxin in human sera. The IHA titres before the treatment of the sera with 2-ME were generally about four times higher than the TN titres and the correlation coefficient between these titres was 0.94. The IHA titres after the treatment of the sera with 2-ME were in good agreement with the TN titres and there was no statistically significant differences between the titres by the two methods. The tetanus antitoxin titres of 50% of the sera were below the minimum protective titres of tetanus antitoxin (0.01 IU/ml). In 19.5% of the sera the antitoxin level (IU/ml) ranged from 0.01 to 0.1, in 20.1% from 0.1 to 1.0 and in 10.4% from 1.0 to 10.0.

Hemagglutination Tests↗

PubMed1984

Intracellular free magnesium in erythrocytes of essential hypertension: relation to blood pressure and serum divalent cations.

Intracellular levels of free Mg2+ in human erythrocytes were determined by 31P NMR spectroscopy in 26 fasted subjects and were correlated with blood pressures and serum levels of total magnesium (bound and free Mg2+) and ionized calcium from the same subjects in a seated position. Untreated hypertensive individuals consistently demonstrated lower levels of intracellular free magnesium (192 +/- 8 microM, n = 11) than either normotensive (261 +/- 9.8 microM, n = 7, P less than 0.001 vs. untreated hypertensive subjects) or hypertensive subjects whose blood pressure had been normalized on therapy (237 +/- 7.8 microM, n = 8, P less than 0.005 vs. untreated hypertensives). For all subjects, strong relationships existed between intracellular free magnesium and diastolic blood pressure (r = -0.85, P less than 0.001) and systolic blood pressure (r = -0.71, P less than 0.001). Significant relationships also were observed between intracellular free magnesium levels and extracellular serum levels of calcium ion (r = -0.77, P less than 0.001) as well as serum concentrations of total magnesium (r = 0.62, P less than 0.001). We conclude that significant depletion of intracellular free magnesium levels are apparent in erythrocytes of subjects with essential hypertension. Furthermore, the close, inverse relationship of free magnesium levels with the height of the blood pressure suggests that abnormalities of intracellular magnesium metabolism may contribute to the pathophysiology of human essential hypertension.

Blood Pressure↗

PubMed1984

Studies of a melanoma tumor-associated antigen detected in the spent culture medium of a human melanoma cell line by allogeneic antibody. I. Purification and development of a radioimmunoassay.

A tumor-associated antigen (TAA) was isolated from spent culture medium (chemically defined serum-free medium) of human melanoma cell line UCLA-SO-M14 (M14). The isolation procedures included concentration, ultrafiltration, gel filtration chromatography, and chloroform:methanol (C:M) extraction. The melanoma TAA activity recovered from the organic phase of the C:M extract was subsequently fractionated by gel filtration and radiolabeled with Na125I. The radioiodinated antigen was further purified by Sephacryl S-200 gel filtration and allogeneic antibody affinity chromatography. With the use of previously characterized anti-TAA allogeneic sera from melanoma patients and 125I-labeled TAA, a radioimmunoassay (RIA) was developed. Protein A-bearing Staphylococcus aureus was used to separate bound and unbound 125I-labeled TAA. The coefficient of variation between experiments and within experiments with unlabeled melanoma TAA as the competitor in the competitive RIA ranged from 8.9 to 20.4%. These variations were consistently lower (8.9-13.6%) at high levels (6 micrograms melanoma TAA/ml) of the competitor than they were (17.3-20.5%) at low levels (0.5 microgram melanoma TAA/ml), suggesting reasonable reproducibility of the assay. A logit versus log plot of the competitive RIA data and analysis by linear regression yielded a straight line. This line represented a 5- to 1,000-ng detection range for melanoma TAA. Analysis of C:M-extracted and Sephacryl S-200-purified melanoma TAA by the competitive RIA revealed a 695-fold purification of the antigen that represented a 37.5% recovery from the spent culture medium. The greatest enrichment of the melanoma TAA was achieved by the C:M extraction step. This step separated the melanoma TAA from other antigens, e.g., fetal antigen and human leukocyte antigens.

Antigens, Neoplasm↗

PubMed1984

Studies of a melanoma tumor-associated antigen detected in the spent culture medium of a human melanoma cell line by allogeneic antibody. II. Immunobiologic characterization.

A tumor-associated antigen (TAA) was isolated from spent culture medium of human melanoma cell line UCLA-SO-M14 (M14). After radioiodination and further purification, it was used in a radioimmunoassay (RIA). When tested in RIA for anti-TAA activity, 56% (111/200) of sera from melanoma patients, 21% (21/100) of sera from sarcoma patients, and 19% (19/100) of sera from carcinoma patients, as well as 12% (6/50) sera from pregnant women and 10% (10/100) apparently normal sera, were positive. The variations (0.25-3.8 micrograms/mg total protein) in specific TAA activity in 20 different batches of spent media collected for 18 months exhibited patterns of gradual increases and decreases, suggesting a cell growth cycle-related phenomenon. Binding between the allogeneic antibody and 125I-labeled TAA was inhibited by 70% (32/47) of melanoma spent media and cells (from culture or biopsy). Conversely, only 7% (3/33) spent medium or membrane extracts of other tumor cells and 0% (1/69) of human normal, fetal, or placental cells were positive in competitive RIA. The TAA was immunologically different from normal tissue antigens, blood-group antigens, human leukocyte antigens, and microbial antigens. These immunobiologic properties of the TAA isolated from M14 spent culture medium and used in the RIA suggested that such TAA was melanoma associated.

Antibodies, Neoplasm↗

PubMed1984

Studies of a melanoma tumor-associated antigen detected in the spent culture medium of a human melanoma cell line by allogeneic antibody. III. Physicochemical properties.

A melanoma tumor-associated antigen (TAA), isolated from spent culture medium of human melanoma cell line UCLA-SO-M14, was purified to mean homogeneity to determine its physical and biochemical nature. Gel filtration and native polyacrylamide gel electrophoretic analyses of the 125I-labeled melanoma TAA revealed that the antigen had a molecular weight in the range of 180,000-190,000. However, ultracentrifugation of melanoma 125I-labeled TAA in a 5-20% sucrose density gradient revealed a sedimentation coefficient to be 4.96 +/- 0.24. Melanoma 125I-labeled TAA focused at a pH of 6.5 by isoelectric focusing. No carbohydrates were detectable by various colorometric methods in the highly purified melanoma TAA fraction, and melanoma TAA failed to bind with several lectins. Its antigenic activity was destroyed by the proteolytic enzymes but was not affected by the glycosidic enzymes or phospholipase A2. The results suggested that the melanoma TAA was most likely a lipoprotein that had a molecular weight of 180,000-190,000, a sedimentation coefficient of approximately 5, and a pl value of 6.5. The protein portion apparently formed the antibody binding site(s).

Antigens, Neoplasm↗

PubMed1984