Biomedical subjects
Publications and source records attributed to V Gupta.
Adenosine deaminase (ADA) activity was studied in 25 patients having different types of leprosy and 25 healthy volunteer as control. There was definite rise of ADA activity in BL (72.9 +/- 6.85), LL (56.7 +/- 3.35) and BT (39.1 +/- 8.28) which was statistically significant when compared to ADA activity in healthy control (9.7 +/- 0.53).
Explore the source record for details and available documents.
Establishment of cell lines in vitro from a human lung cancer xenograft in nude mice resulted in transformed mouse cell lines. The transformed mouse cell lines expressed both mouse-specific and human-specific histocompatibility antigens. Of 3 cell lines, 2 were tumorigenic in BALB/c nude mice but not in normal mice. Tumors formed by the transformed mouse cell lines were fibroblastoid and epithelioid by histology. In addition, tumors exhibited neuroepithelial differentiation by ultrastructural and immunohistochemical analysis. Phenotypically they were similar to the original patient and human xenograft tumor. These data suggest that previous reports of host cell transformation and induction of fibrosarcomas may not be true fibrosarcomas. Human DNA sequences were present in the tumorigenic cell lines, indicating that spontaneous transfection of human tumor DNA into host cells had occurred. The implication of these findings is that human genetic information has been transferred to primary mouse host fibroblasts, which resulted in a transformed as well as a differentiated phenotype.
A review of the literature on the effect of hypoxia on in vitro drug sensitivity had suggested that there was consistently more cytotoxicity under hypoxic conditions for the drugs misonidazole and mitomycin C while there was much conflicting data for the drugs Adriamycin and bleomycin. We have examined the effect of oxygen on the cellular response of Ehrlich's ascites tumor cells to the drugs mitomycin C, misonidazole, Adriamycin, and bleomycin. Significant differences were observed when we compared the cytotoxicity of mitomycin C and misonidazole as a function of oxygen concentration. For the drugs Adriamycin and bleomycin no differential effects of oxygen were noted for a 1-h drug exposure with hypoxia while some differences were noted only for bleomycin for an 8-h drug exposure time. Because differences dependent on oxygen concentration were observed for some drugs but not others at the same experimental conditions, and as indicated by a review of the literature, it is suggested that some of the conflicting data in the literature with respect to some of these drugs may be cell-line dependent. Other variables which may also be of importance were the duration of drug exposure time in hypoxia and cell density. The observed oxygen concentration-dependent changes in cell survival for the Ehrlich cells with drugs examined could not be explained on the basis of changes in drug-induced cellular oxygen consumption.
Electrophysiological studies in 13 patients with thyrotoxicosis (5 men and 8 women, aged 17 to 76 years) are reported. Five patients presented with features of sick sinus syndrome (SSS) (Group A) while the remaining 8 patients (Group B) had no detectable cardiovascular abnormality. Sinus node function (corrected sinus node recovery and sinoatrial conduction time) was abnormal in all Group A but normal in Group B patients. Intra-atrial, artioventricular (AV) nodal, and infranodal conduction time and effective refractory period of atrium were normal in all patients in both groups. Effective refractory period of AV node was decreased in 6 patients (3 in each group). All Group A patients received radioiodine with complete clinical remission of sick sinus state in 4 subjects. Repeat electrophysiological studies in two of these patients, 6 and 12 months after treatment, showed complete normalization of sinus node function. This is the first reported electrophysiological study documenting the occurrence of SSS in thyrotoxicosis reversed by effective antithyroid treatment. We suggest that attempts should be made to identify underlying thyrotoxicosis in all patients with SSS, especially in the older age group. Appropriate medical treatment may prevent unnecessary implantation of permanent pacemakers in such patients.
We generalize the model of [21] in which the author considered a predator-prey system with predators eating only the young ones (or eggs) of the prey species. The prime assumption of the present paper is that the birth rate (per unit individual per unit time) of predators depends not only on the current prey egg-level but also on all previous prey egg-levels. It is seen that under this assumption an otherwise stable system may be stable as well as unstable leading to the conclusion that young predation with time delay is less stable than without it. Finally for the model of [21] we prove a result which shows that large predation rates help in the co-existence of both predator and prey species.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
We have used collagenase to isolate cell populations from different compartments of mouse bone marrow. Cells were obtained from the shaft of the femur, the endosteum, and compact bone. We have studied the growth-enhancing effects of physiologically low oxygen levels on fibroblast colony-forming unit (CFU-F) growth in vitro. Low oxygen levels (0.1%-10% O2) increased CFU-F formation 1.8- to 2.8-fold. However, cells from the compact bone consistently grew with much higher efficiencies (12- to 31-fold) than did cells from femoral cavity and endosteal areas. These data indicate the usefulness of enzymatic methods of isolating cells from compartments of bone and the use of low oxygen atmosphere to enhance stromal cell growth in vitro.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A 2.5-year-old girl who presented with abdominal distension, hepatomegaly, coarse facies, hirsutism and contraction deformities was investigated for mucopolysaccharidoses. Urinary excretion showed increased total glycosaminoglycans (105 mg/mmol creatinine; normal for age 9-20 mg/mmol) with marked increases of dermatan and heparan sulphates. A number of lysosomal enzyme activities were measured on leucocytes, serum and cultured fibroblasts. Normal or high activities were found for alpha-iduronidase, N-acetylgalactosamine-6-sulphatase, beta-galactosidase, arylsulphatase B and beta-glucuronidase. However a marked deficiency of iduronate sulphate sulphatase activity was observed, consistent with a diagnosis of Hunter's disease. Activities were reduced to less than 2% of mean control values in the patient's leucocytes, serum and cultured fibroblasts. Normal activities were measured in samples from the father and younger sister but a partial deficiency (43% of control serum) was found in the mother. Chromosome studies on the patient revealed a partial deletion of the long arm of one X-chromosome, most probably of band Xq25, which was not inherited from either parent. Studies using BrdU indicated that the deleted X chromosome was consistently late replicating, and as a result the Hunter gene was fully expressed on the other X chromosome.
An outbreak of typhoid fever occurred among 54 hospital nurses after a picnic. The salient features were fever (100%), nausea and vomiting (46%), loose motions and abdominal pain (13%), and palpable splenomegaly (63%). None of the patients had any major complications. Blood cultures for Salmonella typhi were positive in 81%, blood Widal was positive (1:320 or more) in 43% and suggestive (1:160) in 25% of the blood culture positive patients. A comparable number of patients were administered chloramphenicol or co-trimoxazole and no differences in response were observed. Bacteriological examination of samples of water from the likely sources revealed it to be unfit for human consumption due to gross faecal contamination.
We demonstrate that postradiation hypoxia during colony formation in vitro enhances radiation sensitivity when cells are irradiated in severely hypoxic states. The presence and magnitude of this phenomenon, if it occurs in vivo, raise questions about the importance of the oxygen effect in the radiation response of tumor cells in vivo and suggest that hypoxia may not be an important factor in the probability of tumor control following radiation therapy.
Explore the source record for details and available documents.
Explore the source record for details and available documents.