Search PubMed⌕ Search

Biomedical subjects

S Das

Publications and source records attributed to S Das.

At least 469 records · Page 26Linked to original sources
PubMed1992

Neuroanatomy of Cysticercus cellulosae (Cestoda) as revealed by acetylcholinesterase and nonspecific esterase histochemistry.

The nervous system of Cysticercus cellulosae, the metacestode stage of the tapeworm Taenia solium, was delineated using histochemical methods for the localization of the enzyme markers; nonspecific esterase and acetylcholinesterase. The main features of the nervous system include a pair of cerebral ganglia, a circumcerebral nerve ring, a rostellar nerve ring, and anterior and posterior nerves and their branches. The posterior nerves form a subtegumental network in the strobila and the bladder wall. A nerve network around excretory tubules could also be demonstrated, suggesting neuronal control of excretion in the metacestode. No sheath was observed around the nervous system. The morphological features described suggest "cephalization" of the nervous system in this parasite.

Acetylcholinesterase↗
PubMed1992

Ultrasonographic evaluation of urethral stricture disease.

Twenty-four male patients with known or suspected urethral stricture disease were evaluated using ultrasonic urethrography and standard retrograde x-ray urethrography for comparative analysis of the two techniques. Each patient also had cystoscopy for direct visual verification of the extent of the stricture. Ultrasonic urethrography proved a simple, yet sensitive and reliable, diagnostic study that can provide more accurate information regarding stricture length, lumen caliber, and extent of spongiofibrosis than radiologic urethrography. It allows examination of the urethra in different planes. The ultrasonic equipment is portable, and ultrasonic study provides the distinct advantage of avoiding ionizing radiation.

Adolescent↗
PubMed1992

Laparoscopic removal of bladder diverticulum.

A large symptomatic bladder diverticulum in a 72-year-old man was removed through laparoscopic dissection. The surgical technique of laparoscopic diverticulectomy is described. Laparoscopic diverticulectomy can be done with minimal morbidity and has distinct advantages over other forms of treatment of bladder diverticula.

Aged↗
PubMed1992

Mutations in the V2 vasopressin receptor gene are associated with X-linked nephrogenic diabetes insipidus.

X-linked nephrogenic diabetes insipidus (NDI) is a rare disorder in which the kidney is insensitive to the antidiuretic hormone, vasopressin. It has been proposed that the kidney-specific V2 vasopressin receptor, a G protein-coupled receptor, is defective in this disorder as both the disease and the receptor map to Xq28. We report six unique mutations in the V2 receptor gene of five unrelated NDI patients, with one patient having two mutations. The most severely affected patient has a nonsense mutation which would terminate the protein in transmembrane domain III. Other mutations include three missense mutations, a frameshift and one small in-frame deletion. These results represent one of the first examples of recessive mutations affecting a G protein-coupled receptor.

Amino Acid Sequence↗
PubMed1992

Congenital thrombophilia among patients with venous thromboembolism.

During a 3-year period we studied 393 adult patients (382 of whom were unrelated) with a history of acute venous thromboembolism. A congenital deficiency state known to predispose to thrombosis was found in 27.2%. Of these, most were due to deficiencies of protein C (9.2%), protein S (7.6%), antithrombin III (5%) or to increased plasma PAI-1 concentration (3.1%) which, in the absence of any known factor that predisposes towards thrombosis, results in a diminished fibrinolytic activity. There was a characteristic pattern between the age of onset (mean 34 years) of thrombosis and individual protein deficiency. Thrombosis appeared spontaneously in 73% of cases with recurrence in 80%. In contrast, in the remaining unrelated patients, 138 (35.1%) in whom venous thromboembolism was secondary and occurred at a mean age of 43 years, and in the other 140 (35.6%) who suffered thromboembolism spontaneously at a later age (mean age 55), there was no permanent protein deficiency state or alteration in fibrinolytic activity and thrombosis recurrence was lower (53.6% and 20.7% respectively). Of the 393 patients, deep vein thrombosis was the most common manifestation; however, in congenital thrombophilia, thrombosis of visceral vessels and Raynaud's syndrome (6%) were also detected.

Acute Disease↗
PubMed1992

The pattern of mycobacterial antigen recognition in sera from Mantoux-negative individuals is essentially unaffected by bacille Calmette-Guérin (BCG) vaccination in either south India or London.

Paired sera were obtained before and 8 weeks after routine BCG vaccination from 20 PPD-S Mantoux-negative individuals who were living adjacent to the Chingleput BCG vaccine trial area in Tamil Nadu and from seven Mantoux-negative school-children in London, UK. Most subjects became Mantoux-positive after vaccination. In ELISA tests against soluble extracts of BCG or Mycobacterium tuberculosis H37Rv or against PPD-S, pre-vaccination antibody titres of South Indian subjects were about twice those of British subjects but there was no increase in titre of antibodies after vaccination of either population. Western blotting showed that even before vaccination, and even in British subjects, antibodies were present that recognized numerous antigenic components in extracts of BCG and M. tuberculosis. There was no consistent difference between band patterns with South Indian and British subjects and any effect of vaccination on the patterns was minimal.

Adolescent↗
PubMed1992

Effect of hypothyroidism on different forms of actin in rat cerebral neuronal cultures studied by an improved DNase I inhibition assay.

An improved DNase I inhibition assay for the filamentous actin (F-actin) and monomeric actin (G-actin) in brain cells has been developed. Unlike other methods, the cell lysis conditions and postlysis treatments, established by us, inhibited the temporal inactivation of actin in the cell lysate and maintained a stable F-actin/G-actin ratio for at least 4-5 h after lysis. The new procedure allowed separate quantitation of the noncytoskeletal F-actin in the Triton-soluble fraction (12,000 g, 10 min supernatant) that did not readily sediment with the Triton-insoluble cytoskeletal F-actin (12,000 g, 10 min pellet). We have applied this modified assay system to study the effect of hypothyroidism on different forms of actin using primary cultures of neurons derived from cerebra of neonatal normal and hypothyroid rats. Our results showed a 20% increase in the Triton-insoluble cytoskeletal F-actin in cultures from hypothyroid brain relative to normal controls. In the Triton-soluble fraction, containing the G-actin and the noncytoskeletal F-actin, cultures from hypothyroid brain showed a 15% increase in G-actin, whereas the F-actin remained unaltered. The 10% increase in total actin observed in this fraction from hypothyroid brain could be totally accounted for by the enhancement of G-actin. The mean F-actin/G-actin ratio in this fraction was about 30% higher in the cultures from normal brain compared to that of the hypothyroid system, which indicates that hypothyroidism tends to decrease the proportion of noncytoskeletal F-actin relative to G-actin.

Actins↗
PubMed1992

Epidemic of acute inflammatory myopathy in Karnataka, south India: 30 cases.

Thirty patients of acute inflammatory myopathy were seen over a short period of 11 months (February to December 1986) at NIMHANS, Bangalore, South India. The characteristic features were: short febrile illness followed a few days later by myalgia, edema of extremities, severe motor weakness and involvement of multiple other systems. Their mean age was 32.3 years and M:F ratio was 4:1. CK levels were increased in all. EMG done in 23 patients showed spontaneous activity in 13 and myopathic pattern in all. Nerve conduction studies revealed abnormalities in 12 cases. Muscle biopsy done in 21 patients showed varying degree of myophagocytosis and inflammatory infiltrates. All patients received steroids for only 6-8 weeks. Twenty-two patients recovered, one developed residual disability and 7 patients died during the acute phase. None of the survivors has developed relapse so far. Such cases with monophasic illness in clusters have not been reported earlier.

Adolescent↗
PubMed1992

The use of flufenamate and forskolin to evaluate the role of cAMP in gonadotropin-releasing hormone-stimulated luteinizing hormone secretion from pituitaries of ovariectomized rats.

Flufenamate which inhibited gonadotropin-releasing hormone (GnRH)-stimulated cAMP production in pituitaries from ovariectomized (72 hr) rats, was used to determine whether ovariectomy induces a change in the role of cAMP as a mediator of luteinizing hormone (LH) secretion. Additionally, the study evaluated the practicability of utilizing forskolin to restore intracellular cAMP concentrations in the presence of flufenamate. Infusions of flufenamate to perifused pituitary tissue blocks did not affect the protein synthesis-independent component of GnRH-stimulated LH secretion, but completely inhibited the protein synthesis-dependent component. Dibutyryl cAMP (dbcAMP) and forskolin potentiated the GnRH-stimulated responses, and restored the LH secretion inhibited by flufenamate, even though these agents were ineffective secretagogues when administered singly. The LH responses affected by forskolin were dependent on protein synthesis, while dbcAMP affected both the protein synthesis-dependent and -independent components of GnRH-stimulated LH secretion. Since the effects of dbcAMP on the protein synthesis-independent component of LH secretion might be due to interactions with GnRH receptors, the results suggest that forskolin might be a better choice for restoring intracellular cAMP levels in the presence of flufenamate when assessing the role of cAMP in gonadotropes. The study also indicates that ovariectomy does not result in a change in the role of cAMP, which appears to be a pivotal, but indirect mediator of the protein synthesis-dependent component of GnRH-stimulated LH secretion.

Animals↗
PubMed1992

Experimental evaluation of preventive and therapeutic potentials of lysozyme.

Therapeutic efficacy and preventive role of egg white lysozyme was evaluated in three types of murine ascitic tumours, namely sarcoma 180, Ehrlich's carcinoma, and Dalton's lymphoma. Lysozyme treatment produced regression of tumour growth and improved the life expectancy of the host. Growth of tumour cells treated in vitro with lysozyme prior to transplantation was also affected. In addition, lysozyme was found to have a preventive effect when administered to normal mice. The antitumour activity, therapeutic and preventive, of lysozyme seems to be due to its action on the tumour cell surface as well as on the host-mediated immune response.

Animals↗
PubMed1992

Evaluation of the cariogenic potential of the intense natural sweeteners stevioside and rebaudioside A.

Stevioside and rebaudioside A, two intense natural sweeteners, that are constituents of the South American plant Stevia rebaudiana, were tested for cariogenicity in albino Sprague-Dawley rats. Sixty rat pups colonized with Streptococcus sobrinus were divided into four groups and fed stevioside, rebaudioside A or sucrose added to basal diet 2000 as follows: group 1, 30% sucrose; group 2, 0.5% stevioside; group 3, 0.5% rebaudioside A, and group 4, no addition. All four groups were sacrificed after 5 weeks. S. sobrinus counts were made and caries was evaluated according to Keyes' technique. There were no differences in food and water intake and weight gains between the four groups. There were significant differences in sulcal caries scores (p < 0.02) and S. sobrinus counts (p < 0.05) between group 1 and the other three groups. There were no significant differences between the stevioside, rebaudioside A and no-addition groups. It was concluded that neither stevioside nor rebaudioside A is cariogenic under the conditions of this study.

Animals↗
PubMed1992

Spectrophotometric study of the relative affinities of teichoic acid for different metal ions.

Spectrophotometric study of the relative affinities of teichoic acid (TA) for Na+, Ca2+, Mg2+, Cd2+, Hg2+, Cu2+ and Pb2+ described on the basis of the disruption of metachromasia of dye 1,9-dimethyl methylene blue (DMMB)-polyanion (TA) system has revealed the following sequence of relative affinities of TA for these metals: Na+ < Ca2+ < or = Mg2+ < Cd2+ < Hg2+ < Cu2+ < Pb2+. Some of the metal ions particularly Pb2+ and Hg2+ have specific interactions with the dye, and induce distinct metachromatic band of the dye even in the absence of the polyanion.

Cations, Divalent↗
PubMed1992

Modulation of fish liver fructose-1, 6-bis phosphatase by ammonia stress.

Hepatic fructose 1, 6 bisphosphatase (Fru-P2ase) from Channa punctatus exhibits 100% and 60% elevations of its maximal catalytic rates (Vmax) at pH 7.5 and 9.5 respectively in summer over those in winter. Both the neutral and alkaline activities of the enzyme are enhanced remarkably (100%) in the winter-adapted fish due to exposure to 10 mg N/1 of unionized ammonia for three weeks. While the neutral activity of the purified enzyme is increased in vitro by NH+4 ions in dose-dependent manner upto about 150 mM NH4, the alkaline activity is found to be activated at a very low concentration of NH4+ (25 mM) and inhibited at 100-150 mM NH4+. The enzyme also shows a characteristics potentiation of 5'-AMP inhibition by NH4+ (125 mM).

Adaptation, Physiological↗
PubMed1992

Penile amputations for the management of primary carcinoma of the penis.

In conclusion, a carefully planned and timed surgical extirpation of the primary carcinoma of the penis should eliminate the possibility of local recurrence. The decision between partial or total amputation of the penis is based on the site and extent of the primary tumor. The decision must not compromise the goal of complete clearance of the primary tumor.

History, 18th Century↗
PubMed1992

Metabolism of silicon as a probable pathogenicity factor for Mycobacterium & Nocardia spp.

The role of silicon (Si) in metabolism and growth of 22 strains of mycobacteria and 3 strains of nocardiae, which were mostly pathogenic, was studied on Kirchner's medium solidified with sodium metasilicate (KSM) and the C-free solidified metasilicate minimal medium (SMM) consisting of mineral salts only. On KSM, initial growth of mycobacteria appeared to be better, compared with that on Lowenstein-Jensen medium (LJM), although subsequent growth on the former was slower. On SMM lacking C, growth of mycobacteria and nocardiae could be achieved, only after repeated passages. These findings indicate that the mycobacteria and nocardiae are able to utilise Si at least to a limited extent, possibly as an alternative to C, with greater chances of survival.

Culture Media↗
PubMed1992

Anti-amoebic antibody levels in gastro-intestinal disorders.

Serum anti-amoebic antibody levels were studied in 91 cases having clinical presentation of bowel disorders and 31 cases of control. Anti-amoebic antibody was positive in significant dilutions in 38 cases (31.15%) in total comprising 9 cases out of 22 cases showing presence of Ent histolytica cyst in stool, 13 cases who were positive for ova, parasite and cysts other than Ent histolytica in stool and 16 cases out of 70 cases with negative stool findings. It was positive in 5 cases out of 9 diagnosed cases of amoebic liver abscess. Assessment of immunoglobulin levels in amoebic liver abscess cases revealed high levels of immunoglobulin G and immunoglobulin M.

Amebiasis↗