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Biomedical subjects

S Das

Publications and source records attributed to S Das.

At least 613 records · Page 34Linked to original sources
PubMed1985

Evaluation of vitamin A and C status in normal and malignant conditions and their possible role in cancer prevention.

A comparative study has been made on the levels of vitamins A and C in normal and malignant conditions in human and murine subjects. Further, the effect of supplemental vitamins A and C on tumor take, host-survival and tumor growth have been studied in a number of transplantable and induced tumors in mice. The vitamins were assayed in sera samples from normal subjects, patients with cancer of the uterine cervix or ovary, and leukemia and lymphoma patients. Among the murine group the tumors included sarcoma 180 in solid and ascitic form, benzo[a]pyrene-induced fibrosarcoma, Dalton's ascitic lymphoma and Schwartz lymphoblastic leukemia. The serum level of vitamin C was found to be lower than that of the normal controls in all cases studied. The level of vitamin A was found to be higher in cancer patients in the human group and lower in the murine group when compared with their normal controls. Studies on murine tumors showed that supplementary vitamins administered at the initial phase of tumor development reduced the percentage tumor take and the rate of tumor growth, and improved host survival, indicating that these vitamins have a protective role in the murine system.

Animals↗
PubMed1985

Placental hormones as possible markers in gynaecological cancer.

Two placental hormones (human chorionic gonadotropin and human chorionic somatotropin) were assayed in serum of patients bearing a wide variety of malignant tumours. The incidences of these hormones were found to be higher among female patients. Further studies revealed that the incidence was high in patients with malignant tumours of the gonads, breast, uterus and cervix. It was shown that these hormones are the products of tumour cells and that they are released in circulation. Studies on cervix cancer suggest that they may be useful aids in following the course of therapy.

Adult↗
PubMed1984

Hormone receptors in rapidly progressing breast cancer.

Biopsy specimens from 85 Tunisian breast cancer patients were compared with those of 95 American breast cancer patients for estrogen receptor (ER) and progesterone receptor (PR) levels. Tunisian patients with rapidly progressing breast cancer (RPBC) had lower ER levels than American patients or Tunisian patients without evidence of RPBC. Lower ER levels in the earliest stage of RPBC, which presents without inflammatory signs, supported epidemiologic and pathologic studies indicating that rapid growth as reported by the patient is an important aspect of RPBC. Low ER levels were generally found in young, premenopausal Tunisian women with advanced RPBC; multivariate analyses suggest that age was the most important correlating factor. In the Tunisian patients, ER levels showed a direct correlation with response to therapy. No consistent relationship between American and Tunisian patients or subgroups was observed for PR levels. These results indicate the need for reevaluating the routine use of oophorectomy in RPBC.

Age Factors↗
PubMed1984

Diacylglycerol causes major structural transitions in phospholipid bilayer membranes.

We demonstrate for the first time that major structural changes are imposed on various phospholipid bilayers by diacylglycerol, a product of phosphatidylinositol metabolism. By 5 mole percent in phosphatidylethanolamine a lamellar to hexagonal transition starts that is complete at 10 mole percent. At 30 mole percent it causes the same transition in phosphatidylcholine and forms a cubic phase at 80 mole percent. Diacylglycerol disorders the phosphatidylserine lamellar phase. We view the formation of the non-lamellar phases as diagnostic of the destabilizations that diacylglycerol can cause in membranes. We suggest how DAG may act both in its specific activation of membrane enzymes and in inducing membrane fusion.

Animals↗
PubMed1984

Morphine inhibition of the insulin-inducible form of hepatic tyrosine aminotransferase.

Morphine treatment in normal intact rats caused a dose-dependent increase in hepatic tyrosine aminotransferase (TAT) activity, as demonstrable up to 2 hr of exposure to the opioid alkaloid. However, such increase in TAT activity was invariably preceded by a prior decline in the enzyme level, as observed after 15 min of morphine treatment. Such an initial decline in activity was not demonstrable in diabetic animals. Further studies indicate that morphine inhibited the insulin-induced increase in TAT activity, a phenomenon which could be reversed by the opioid antagonist naloxone. The results suggest an opioid control mechanism in the regulation of the insulin-inducible form of TAT and indicate the possibilities of a trophic role of endogenous opiates in gluconeogenesis.

Animals↗
PubMed1984

Analysis of a eukaryotic beta-galactosidase gene: the N-terminal end of the yeast Kluyveromyces lactis protein shows homology to the Escherichia coli lacZ gene product.

The LAC4 gene of Kluyveromyces lactis, encoding the enzyme beta-galactosidase was mapped on a cloned DNA fragment and the sequence of the 5' end was determined. This sequence includes the 5' regulatory region involved in the induction by lactose and the N-terminal end of the protein coding region. Comparison of the deduced amino acid sequence of this eukaryotic enzyme with the N-terminal end of the Escherichia coli beta-galactosidase revealed substantial homology. Two major RNA initiation sites were mapped at -115 and -105. A number of structural peculiarities of the 5'non-coding region are discussed as in comparison to Saccharomyces cerevisiae genes.

Amino Acid Sequence↗
PubMed1984

The exercise response in idiopathic dilated cardiomyopathy.

In order to more clearly define the exercise response of idiopathic dilated cardiomyopathy (IDC), 20 patients in this study with strictly defined IDC were evaluated with radionuclide ventriculography and invasive hemodynamic monitoring. Severe cardiovascular impairment was present at rest, and peak supine exercise produced progressive left ventricular (LV) dilatation in both diastole and systole (mean +/- SEM from 172 +/- 14 to 212 +/- 22 ml/m2 at end-diastole and from 137 +/- 14 to 170 +/- 22 ml/m2 at end-systole; both p less than 0.03). There were marked increases in LV and right ventricular filling pressure (from 17 +/- 2 to 36 +/- 3 mmHg and from 7 +/- 2 to 15 +/- 2 mmHg, respectively; both p less than 0.0001) and increased pulmonary artery pressure. Mean LV ejection fraction did not change significantly with exercise (22 +/- 2 to 23 +/- 3%; p greater than 0.8), but individual patients demonstrated substantial variability. Cardiac output rose less than in normals and increases were brought about primarily by subnormal heart rate increases. High resting and exercise systemic and pulmonary vascular resistance were indicative of limited vasodilator reserve. Despite marked hemodynamic abnormalities, 10 of the 20 subjects had well preserved exercise capacity (greater than or equal to 12 min exercise duration). These patients as a group had significantly lower resting heart rate and higher exercise cardiac output and lower exercise systemic vascular resistance. However, they did not differ from the other patients with respect to resting LV function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Surgical management of benign renal cysts causing obstruction of renal pelvis.

During the last fifteen years, 6 adult patients were treated in whom obstruction of the ureteropelvic junction or the renal pelvis was caused by a benign renal cyst. The cyst extended from the renal hilus in each case and had turgor sufficient to overcome the pressure of intrapelvic urine. Operative unroofing of the cyst relieved the obstruction in each. In 5 of 6 cases, the postoperative radiographic appearance of the kidney showed marked improvement. Each patient was followed for at least five years, and no recurrence of the obstruction was noted. Operative treatment is recommended when a renal cyst causes significant obstruction of the major calyceal or renal pelvic outflow.

Female↗
PubMed1984

The binding of 3H-quinuclidinyl benzilate to cholinergic muscarinic receptors in rat brain region following chronic treatment with morphine and during abstinence.

Chronic morphine treatment (subcutaneous pellet implantation of four morphine pellets) caused significant tolerance to morphine analgesia as observed at zero and 6 hrs. after pellet removal. However, such treatment failed to elicit any changes in striatal muscarinic receptors using (3H)-QNB binding studies. At 24 hours after pellet removal there was significant development of physical dependence but the affinity (Kd) as well as density (Bmax) of striatal muscarinic receptors remained unaffected. Although naloxone caused marked precipitation of abrupt withdrawal in morphine tolerant rats, it also failed to produce any changes in striatal muscarinic receptors. Results indicate that any cholinergic involvement in opiate tolerance and physical dependence does not involve an effect on muscarinic receptors.

Animals↗
PubMed1984

Ureteropelvic junction obstruction with associated renal anomalies.

Ureteropelvic junction obstruction when associated with other congenital anomalies of the kidney often presents a diagnostic and therapeutic dilemma. These anomalies include fusion abnormalities, malrotation, renal ectopia and duplicated systems. We report our experience in the management of 27 patients with ureteropelvic junction obstruction and associated renal anomalies, including horseshoe kidney in 9, duplicated systems in 12, ectopic kidney in 5 and malrotation in 1.

Adolescent↗
PubMed1984

Pre-cystoscopic diagnosis of bladder tumour by modified intravenous urography.

Intravenous urography is the primary radiographic procedure used to evaluate patients with haematuria. During the last 15 years a modification of intravenous urography, using delayed films of the bladder, has aided the correct pre-cystoscopic diagnosis of bladder tumor in 82 of the 95 patients seen with this condition at our medical centre. After injection of contrast medium, anteroposterior and oblique views of the abdomen are obtained up to 15 min. Our modification consists of taking delayed films of the full bladder 1/2 h and 1 h later, followed by a post-voiding film. A bladder tumour appears as a filling defect or space-occupying lesion and can be distinguished from other lesions. Such delayed films increase the yield in the radiographic diagnosis of bladder tumours.

Aged↗
PubMed1984

Transformation of Kluyveromyces fragilis.

For the transformation of the yeast species Kluyveromyces fragilis, we have constructed a vector containing a bacterial kanamycin resistance (Kmr) gene, the TRP1 gene of Saccharomyces cerevisiae, and an autonomously replicating sequence of Kluyveromyces lactis called KARS2 . By utilizing the method based on treatment by alkali cations and with the Kmr gene as the selective marker, a wild-type strain of K. fragilis was transformed to resistance against the antibiotic G418 . In the transformed cell the plasmid replicates autonomously. The same plasmid could also be used to transform S. cerevisiae trp1 mutant to Trp+. Thus, KARS2 of K. lactis enables the vector to replicate in K. fragilis, K. lactis, and S. cerevisiae, whereas ARS1 of S. cerevisiae allows autonomous replication only in S. cerevisiae.

Ascomycota↗
PubMed1984

A comparative study of ectopic production of human chorionic gonadotropin and human chorionic somatotropin by carcinoma of the uterine cervix.

A comparative study was made on the ectopic production of chorionic gonadotropin (hCG) and chorionic somatotropin (hCS) by carcinoma of the uterine cervix. Incidence of hCG in the sera of cancer patients was much higher than hCS. hCS has a better prospect in early detection of cancer cervix than hCG. All hCS-producing tumors and the majority of hCG-producing ones were histologically diagnosed as squamous cell carcinoma. The source of hCG and hCS were found to be the tumor cells. A fall or disappearance of detectable hCG and hCS was noted following surgery or radiotherapy.

Adenocarcinoma↗
PubMed1984

Effects of a placental hormone, human chorionic somatomammotropin on normal and malignant cells.

Studies were made on the effects of human chorionic somatomammotropin (HCS) on normal and malignant cells and tissues in Swiss mice. HCS was found to produce a significant increase in the fresh weight of normal liver, kidney, spleen, testis, ovary and uterus. Total cell counts of leukocytes and erythrocytes were elevated. The percentage of granulocytes in blood was found to be increased and the percentage of lymphocytes was decreased following HCS treatment. HCS stimulated the growth of ascitic Ehrlich's carcinoma and Sarcoma 180, and nucleic acid synthesis by these tumor cells. A depression in the mitogen induced blastogenesis of lymphocytes was also noted following HCS treatment.

Animals↗