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Biomedical subjects

R Gupta

Publications and source records attributed to R Gupta.

At least 685 records · Page 38Linked to original sources
PubMed1989

Subunit structure of porcine submaxillary mucin.

The structure of a high molecular weight fraction of porcine submaxillary mucin was studied by using degradative techniques. Reduction of disulfide linkages released mucin subunits together with an associated protein(s) of approximately 140 kDa. The molecular weights of the subunits ranged from approximately 0.5 x 10(6) to 2.5 x 10(6). Trypsinization of subunits generated glycosylated domains and small, poorly glycosylated or nonglycosylated tryptic peptides. The glycosylated domains, which have an average molecular weight of approximately 270K, possess an unusual amino acid composition containing only nine different amino acids. The minor amino acids which are absent from the glycosylated domains but which are consistently present in both the mucin and the mucin subunits were recovered in the tryptic peptides. Pronase digestion of the glycosylated domains generated smaller fragments of approximately 17 kDa. Comparing these results to the partial cDNA sequence for porcine submaxillary mucin reported by Timpte et al. [(1988) J. Biol. Chem. 263, 1081-1088] suggests that the glycosylated domains consist of variable numbers of the 81 amino acid tandem repeat observed in the cDNA sequence. Further, the fact that porcine submaxillary mucin contains subunits, link proteins, and glycosylated domains suggests that its structure is similar to that described for cervical and intestinal mucins. Intact mucin, mucin "subunits", and the glycosylated domains are all polydisperse with respect to molecular weight, indicating that mucin polydispersity is due to variability in the number of units linked together as well as to variability in the size of the units.

Animals↗
PubMed1989

Centchroman--a non-steroidal anti-cancer agent for advanced breast cancer: phase-II study.

Treatment with Centchroman (3,4-trans-2,2-dimethyl-3-phenyl-4-p-(beta-pyrrolidinoethoxy) phenyl-7-methoxy chroman) has been evaluated in 4 male and 75 female patients with advanced breast cancer. The overall response rate, including both male and female cases, was 40.5%. Among the female patients, the overall response rate was 38.7%. The median duration of response was 6 months. One of the 4 male patients showed a complete response and 2 showed partial responses. The responses were more marked for bone, pulmonary, soft tissue, skin and lymph-node metastases than for liver metastases.

Adult↗
PubMed1989

Light scattering studies of bovine skin proteodermatan sulfate.

The proteodermatan sulfate (PDS) of bovine skin is a low molecular weight proteoglycan with a molecular structure consisting of a protein chain and a sulfated polysaccharide chain covalently linked at the 4-serine of the protein. Static and dynamic laser light scattering methods have been used to determine the weight-average molecular weight, Mw, zeta-average radius of gyration, Rg zeta, and zeta-average translational diffusion coefficient, Dto, zeta, of bovine skin PDS. We have also characterized the two components of PDS, i.e., the protein core and the dermatan sulfate (DS) chain. (The latter contained an N-terminal-linked penta- or tetrapeptide.) Interpretation of the PDS data is complicated by the block copolymer nature of its structure. When appropriate corrections are made, our results indicate that Mw for PDS monomer is 62,000 when dissolved in 4M guanidine hydrochloride (GdnHCl), and increases to 610,000 in 0.15M NaCl. Mw for the core protein in 4M GdnHCl is 39,000, and this also increases substantially to 650,000 in 0.15M NaCl. In contrast, Mw for the DS chain is 24,000 in 0.15M NaCl, indicating that there is minimal self-association of DS in 0.15M NaCl. Thus we conclude that the self-association of PDS involves the protein core. Comparison of Rg zeta and Rh, the average hydrodynamic radius, suggests that trace amounts of aggregation persist for the PDS and its core protein even in 4M GdnHCl. This conclusion is supported by evaluation of the second moments of the dynamic light scattering correlation function. Comparisons of the observed Dto, zeta for PDS with predicted values using hydrodynamic theory are consistent with a "lollipop" conformation for the molecule.

Animals↗
PubMed1989

Long acting somatostatin analogue in dumping syndrome.

The effect of long acting somatostatin analogue, SMS 201-995, on postprandial dumping syndrome was studied in eight patients with Billroth II gastric resection. Each patient was subjected to two oral glucose challenges with 75 g glucose. One challenge was premedicated with 50 micrograms SMS 201-995 subcutaneously 15 min before the oral intake of glucose, the other with placebo. With placebo all patients experienced the subjective symptoms of the early dumping syndrome with significant (P less than 0.001) increases (mean (s.d.)) in pulse rate (from 66 (8) to 102 (10) beats/min), in packed cell volume (from 0.36 (0.05) to 0.43 (0.1) l/l) and in the plasma levels of vasoactive intestinal polypeptide (from 3.0 (0.5) to 10.2 (1.8) pmol/l). During the somatostatin study the subjective symptoms and the changes in the various parameters were not detected. In the control study seven patients showed postprandial hypoglycemia. In these patients significant elevations (P less than 0.001) in the insulin level (from 10 (0.9) to 40 (9.1) microE/ml) and gastric inhibitory peptide (GIP) concentration (from 100 (13) to 220 (41) ng/l) were seen, compared with the initial values. During the application of SMS 201-995 hypoglycaemia did not develop and plasma insulin and GIP concentrations remained unchanged. These results indicate that the long acting somatostatin analogue alleviates the symptoms of early and late postprandial dumping syndromes.

Double-Blind Method↗
PubMed1989

Presacral neurilemoma (schwannoma)--report of a rare case.

A rare case of presacral neurilemoma is reported herein. Despite the large size of the tumor and the extensive destruction of the sacrum, the patient was almost asymptomatic. Accurate diagnosis depends on careful rectal examination and computerized axial tomography is the most useful single investigation. Surgery is the only treatment and for large lesions, the abdominal approach is usually preferred. Recurrence is rare and patients live a long, symptom free life even after partial resection.

Humans↗
PubMed1989

DNA adduct formation, metabolism, and morphological transforming activity of aceanthrylene in C3H10T1/2CL8 cells.

Aceanthrylene (ACE), a cyclopenta-fused polycyclic aromatic hydrocarbon (CP-PAH) related to anthracene, has been studied for its ability to be metabolized, to form DNA adducts, and to morphologically transform C3H10T1/2CL8 mouse embryo fibroblasts in culture. Although ACE has been previously shown to be a strong mutagen in Salmonella typhimurium strains TA89 and TA100, it did not transform C3H10T1/2 cells (0.4-16 micrograms/ml) under 2 treatment protocols: treatment (for 24 h) 1 day after seeding the cells; treatment (for 24 h) 5 days after seeding the cells. Both protocols are effective in detecting the morphological transforming activity of PAH and CP-PAH and the latter protocol has been shown to be effective in detecting chemicals which are active in the first protocol only with the additional treatment of the cells with a tumor promoter. ACE is metabolized by C3H10T1/2 cells to ACE-1,2-dihydrodiol (the cyclopenta-ring dihydrodiol) at a rate of 450 pmoles ACE-1,2-dihydrodiol formed/h/10(6) cells. ACE-7,8-dihydrodiol and ACE-9,10-dihydrodiol, identified as major Aroclor-1254-induced rat liver microsomal metabolites from their UV, NMR, and mass spectral data, were not identified in incubations of C3H10T1/2 cells with ACE. ACE-DNA adducts in C3H10T1/2 cells were isolated, separated, identified, and quantitated using the 32P-postlabeling method. ACE forms 4 major adducts and each was identified as an ACE-1,2-oxide/2'-deoxyguanosine adduct. The level of adduction was 2.18 pmoles ACE adducts/mg DNA after a 24-h incubation of ACE (16 micrograms/ml) with C3H10T1/2 cells. ACE-DNA adduct persistence and repair were evaluated in C3H10T1/2 cells using a hydroxyurea block after ACE treatment. ACE-DNA adducts were not repaired under the conditions used in the morphological transformation studies. Thus, ACE provides an interesting example of a mutagenic PAH which is metabolized by C3H10T1/2 cells to active intermediates, forms relatively stable and persistent 2'-deoxyguanosine adducts in C3H10T1/2 cells, and yet induces no detectable morphological transforming activity under the experimental conditions used.

Animals↗
PubMed1989

In vitro formation of organ-specific ultimate carcinogens of 4-dimethylaminoazobenzene and urethan by microsomes.

In order to determine the organ-specific carcinogenicity of 4-dimethylaminoazobenzene (4-DAB) and urethan, their metabolites formed in vitro by incubation with the microsomes from liver, lungs, brain and kidneys of rats were isolated by thin-layer chromatography. 4-DAB was found to be metabolized to give two major products, 4-aminoazobenzene and N-hydroxy-4-aminoazobenzene, only when incubated with liver microsomes. These metabolites were not detected when microsomal suspensions of lungs, brain and kidneys were used. Similarly, urethan was found to yield three metabolites, N-hydroxy derivative of ethyl carbamate, N-hydroxyvinyl carbamate, and epoxy derivative of ethyl carbamate, on incubation with lung microsomes, but not with the microsomes from liver, brain and kidneys. As the potential carcinogenic moieties were only formed by incubating these two compounds with the microsomes of their target organs, their organ-specific carcinogenicity may be explained.

Animals↗
PubMed1989

Appearing and disappearing CT scan abnormalities in epilepsy in India--an enigma.

In 230 consecutive cases of epilepsy, CT abnormalities were found in 51.7%. Out of these, 91 cases (39.5%) had non specific abnormalities consisting mostly of ring lesions, hyperdense disc lesions with surrounding oedema in enhanced scans and in a small percentage hypodense lesions, generalised brain oedema and calcifications. All these cases were treated with anticonvulsant drugs alone. A follow up scan was possible in 31 cases, 12 weeks or later, after the control of the seizures. Out of these 31 cases, 24 showed a complete or significant resolution and five remained unchanged. Two of these cases showed an increase in the lesions which resolved on treatment with antituberculous drugs. These lesions therefore may have an aetiology other than tuberculosis in the majority of cases and there is ample justification in treating them initially with anticonvulsant drugs only.

Adult↗
PubMed1989

Presence of an intron in elongator methionine-tRNA of Halobacterium volcanii.

The gene for the elongator (internal) methionine transfer RNA (tRNA(mMet)) in the archaebacterium Halobacterium volcanii contains a 75 base pair intron (intervening sequence) and lacks the 3'-terminal CCA sequence of the mature tRNA. There is a single copy of this gene in the genome and it is expressed. Northern hybridization experiments indicate that the precursor is processed to produce mature tRNA and a free intron species. A secondary structure of the transcript can be formed in which the anticodon stem of the tRNA is extended. Two symmetrically placed three-base bulge loops separated by a 4 base pair stem are present in this extension. The cleavage sites for the removal of the intron are placed between the middle and 3' residues of these loops.

Base Sequence↗
PubMed1989

Fine-needle aspiration biopsy sampling in renal transplantation: interstitial cellular infiltrates and major histocompatibility complex class-II antigen expression in renal tubular cells.

The dynamics of major histocompatibility complex (MHC) class-II (DR) antigen products in renal tubular cells and cellular infiltrations in the interstitium of the kidney following renal transplantation without immunosuppressive therapy are presented. DR antigen in 27 normal kidneys and in 18 of 19 kidneys transplanted as autograft showed no DR-antigen expression on their tubular cells. These DR-antigen-negative tubular cells could be induced to express the antigen during courses of untreated rejection both in primary (n = 6) and repeat (n = 4) allografts. Parallel to the increasing DR-antigen expression in the allograft, the autologous kidney expressed this antigen with the same time dependency and with the same intensity. Graft infiltrating cells were evaluated by daily fine-needle aspiration biopsy and core biopsy. Induction of DR antigen was associated with a significant infiltration of blastogenic cells and monocytes/macrophages in the allograft. During rejection of the allograft no cellular infiltrate was noted in the autograft, but during an initial time period after allograft removal cellular infiltrates were seen. Following both courses of rejection DR antigen returns to negative by 6-8 days as did blastogenic cells and monocytes/macrophages in the autograft interstitium. Inducible antigen expression in normally DR-antigen-negative allograft parenchymal cells during rejection is shown to depend on inflammatory cells in the graft. The antigen expression is not restricted to the tissue transplanted, but also affects autologous tissue of the host organism.

Animals↗
PubMed1989

Extrauterine mixed mesodermal tumour of ovary with heterologous element.

The ovary is very rare site of mixed mesodermal tumour. The present case occurred in postmenopausal woman aged 52 years, in right ovary with endometrioid carcinomatous component admixed with chondrosarcomatous component and squamous element. The patient was disease free at one year follow up, with no evidence of local recurrence and distant metastases and was treated post-operatively with combination therapy of radiotherapy and chemotherapy. The review of literature is discussed briefly, with its histogenesis and its differential diagnosis from immature teratoma, malignant teratoma, sertoli leydig cell tumour containing islands of cartilages and embryonal carcinoma of ovary.

Female↗