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S De

Publications and source records attributed to S De.

At least 19 recordsLinked to original sources
PubMed1992

Carbachol stimulates adenylate cyclase and phospholipase C and muscle contraction-relaxation in a reciprocal manner in dog iris sphincter smooth muscle.

In the dog iris sphincter, muscarinic acetylcholine receptors are coupled either to the stimulation of phospholipase C and muscle contraction or to the stimulation of adenylate cyclase and muscle relaxation, this was found to be dependent upon the concentration of the muscarinic agonist. In contrast to the dog, muscarinic receptors in iris sphincters from different mammalian species were found to be coupled to phospholipase C and contraction at all concentrations of carbachol investigated (1-100 microM). In the dog sphincter, lower concentrations (less than 5 microM) of carbachol stimulated myo-inositol 1,4,5-trisphosphate (IP3) production, inhibited cAMP formation and induced contraction, and higher concentrations (greater than 5 microM) enhanced cAMP formation, inhibited IP3 production and induced relaxation. The mechanisms for the stimulatory effects on cAMP formation through muscarinic receptors were investigated. Carbachol (25 microM) increased both basal and isoproterenol- and forskolin-stimulated cAMP levels. Atropine inhibited the carbachol-stimulated increase in cAMP levels in a dose-dependent manner with an IC50 of 9 nM. Intracellular Ca2+, derived from IP3-induced Ca2+ release and/or from muscarinic receptor-operated Ca2+ influx, and protein kinase C may mediate the muscarinic receptor-linked rise in intracellular cAMP. This conclusion is supported by the following findings. (1) At short time intervals (less than 1 min) carbachol (25 microM) increased IP3 production and contraction and this was followed (between 1 and 20 min) by cAMP formation and muscle relaxation. (2) Carbachol-stimulated IP3 production was detected at a concentration of the agonist 26-fold lower than that required for cAMP formation, and it was completely blocked by the phorbol ester, phorbol 12,13-dibutyrate (50 nM). (3) A Ca(2+)-calmodulin stimulated adenylate cyclase was demonstrated in membranes from dog iris sphincter but not in that from rabbit and bovine. (4) Trifluoperazine (0.1 microM), a calmodulin antagonist, inhibited the carbachol-stimulated cAMP accumulation. (5) The Ca2+ ionophore A23187 and the phorbol ester increased cAMP production in a dose-dependent manner. A23187 potentiated cAMP production induced by either carbachol or by the phorbol ester. (6) Muscarinic stimulation of cAMP production persisted even after the tissue was pretreated with the phorbol ester or staurosporine. (7) Nifedipine (0.01-0.5 microM), a Ca2+ channel antagonist, inhibited carbachol stimulation of cAMP production, suggesting the presence of a muscarinic receptor-operated Ca2+ influx pathway in this tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenylyl Cyclases↗
PubMed1992

Alterations of ion-dependent ATPase activities in the brain of Singi fish, Heteropneustes fossilis (Bloch), by triiodothyronine.

The activities of Na+K(+)- and Mg(2+)-ATPases in mitochondrial, microsomal, and cytosolic fractions of Singi fish (Heteropneustes fossilis Bloch) brain were investigated after injections of various doses (0.012, 0.025, 0.05, and 0.10 micrograms/g) of triiodothyronine (T3) for 3 consecutive days. Both ATPases were found in the mitochondrial and microsomal fractions. The cytosolic fraction showed only Mg(2+)-ATPase activity. Mitochondrial Na+K(+)-ATPase activity increased to almost the same level in fish treated with 0.025, 0.05, or 0.10 micrograms of T3/g, while the T3 dose of 0.012 micrograms/g was ineffective in this respect. Microsomal Na+K(+)-ATPase activity increased to about the same level with all of the doses of T3 used. No detectable amount of Na+K(+)-ATPase was found in the brain cytosolic fraction. Mitochondrial Mg(2+)-ATPase activity was enhanced with 0.025, 0.05, and 0.10 micrograms of T3/g. The last dose, however, produced a higher increase in activity than the other two doses. Surprisingly, microsomal and cytosolic Mg(2+)-ATPase activity was not increased by T3 treatment. Although T3 concentrations rose sharply after each T3 injection, the serum T3 level in T3-injected fish was not different from that in the control as observed on the fourth day. The T3-induced rise of Na+K(+)- and Mg(2+)-ATPase activities was inhibited by cycloheximide treatment. Immersion of Singi fishes in thiourea significantly reduced brain Na+K(+)-ATPase activity in microsomal and mitochondrial fractions but decreased Mg(2+)-ATPase activity only in the mitochondrial fraction. Three consecutive daily injections of T3 (0.10 micrograms/g) into the thiourea-treated fishes increased their ATPase activities even beyond the control level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Combined therapy in advanced head and neck cancers.

The results of single modality treatment using surgery or radiotherapy alone in advanced head and neck cancers are known to be unsatisfactory. The present study analyses 252 cases with stage III and IV resectable cancers of the head and neck region selected to be treated by a combined regime of pre- or post-operative radiation and radical surgery. Only 193 patients completed the treatment protocol. There were 58 cases (33.5 per cent) who failed either at primary or regional sites or both. Nine cases (five per cent) developed distant metastasis. Absolute and determinate four year disease-free survival was 55 per cent and 61 per cent respectively. Early lesions (stage I and II) have been excluded from the study. The study indicates that a reduction in primary and regional failures correlates well with a combined therapy, though prolonged treatment may affect patients' compliance to some extent.

Adult↗
PubMed1992

The role of radiation therapy in the management of spinal cord compression due to extramedullary haematopoiesis in thalassaemia.

Extramedullary haematopoiesis associated with thalassaemia leading to spinal cord compression is an extremely rare event in the course of the disease. The efficacy of radiation therapy is advocated in the management of such a complication. Two patients with thalassaemia, who had presented with spinal cord compression, were successfully treated by a modest dose of local radiotherapy. In one of the patients, however, radiotherapy was resorted to after an initial decompressive laminectomy and partial removal of the intraspinal haematopoietic mass proved unsuccessful. The other patient was managed solely by radiation therapy.

Adult↗
PubMed1991

Karyotype studies of patients with gonadal tumors.

Chromosomes from the peripheral blood of 10 patients with gonadal tumors were studied to detect any inherent chromosomal defect. Aneuploidy, breakages and loss of chromosome X were observed. In all cases the karyotype was compatible with the phenotype.

Adenocarcinoma, Mucinous↗
PubMed1991

Demonstration of putative thyroid hormone receptor in the brain nuclei of Singi fish, Heteropneustes fossilis (Bloch).

A single injection of [125I]triiodothyronine (T3) with or without stable T3 in Singi fish, Heteropneustes fossilis (Bloch), showed that the fish brain has saturable binding sites and that the specific uptake is 60-70% higher than the nonspecific uptake. The distribution kinetics of [125I]T3 in the serum, whole brain, and brain nuclei after a single injection of the labeled hormone showed that the removal of [125I]T3 from the serum was very rapid with the t1/2 of about 3.3 hr and the incorporation of the hormone into the brain and brain nuclei were very slow and achieve a maximal value after 4-6 hr of postinjection. The binding of [125I]T3 to the isolated brain nuclei of Singi fish was further studied in vitro. Binding was linearly increased with the increasing concentration of the DNA (nuclei). The binding achieved equilibrium between 15 and 20 min at 27 degrees and was stable at least for 1 hr. The binding was reversible in the presence of excess unlabeled T3. Scatchard analysis showed only a single class of binding sites. The mean dissociation constant (Kd) is 2.15 +/- 0.45 x 10(-10) M and maximum binding capacity (MBC) is 0.044 +/- 0.024 pmol/mg DNA. The relative binding affinities of thyroid hormone analogs for T3 sites were as follows: TRIAC greater than T3 greater than TETRAC greater than T4 greater than reverse T3 greater than T2. These findings were similar to those for other animals. Therefore, the nuclear binding sites in Singi fish brain, as demonstrated, may be regarded as thyroid hormone receptors.

Animals↗
PubMed1991

Role of radiotherapy in the management of primary carcinoma of the fallopian tube.

Primary fallopian tube carcinoma is a rare neoplasm. It may be postulated that postoperative loco-regional radiotherapy is a valuable adjunctive in the overall management of the tubal carcinoma. However, we can't advocate the efficacy of this approach authentically due to a very small number of cases. A prospective controlled and randomized trial with larger patient number may yield some definite conclusions regarding it's optimal management.

Carcinoma↗
PubMed1991

Primary lymphoma of the brain--a report of 5 cases and review of the literature.

Five cases of primary lymphoma of the brain are reported and the literature reviewed. The diverse clinical spectrum at presentation and variable response to therapy are few of its unique features. The literature is reviewed briefly and the importance of diagnosis at an early stage and prompt institution of therapy in form of radiation therapy and chemotherapy when indicated is stressed.

Adult↗
PubMed1990

Primary gastric lymphoma: a prospective analysis of 12 cases and review of the literature.

The clinicopathological features of 12 cases of primary lymphoma of the stomach are reviewed, and the efficacy of various treatment modalities is evaluated. The presenting symptomatology and the radiological signs were found to be similar to those of gastric carcinoma. Gastroscopy and computed tomography (CT) proved to be effective diagnostic and staging tools. There were two patients of stage I, seven patients of stage II, and three patients of stage IV. Multimodal therapy involving judiciously combined surgery, radiation therapy, and chemotherapy produced early complete remission in all the nine patients with localized disease, and all of them are disease-free at a minimum follow-up period of 12 months. These results are irrespective of whether surgery formed part of the treatment regimen. The relevant literature is reviewed, and the present status of the efficacy of nonsurgical therapy is evaluated.

Adolescent↗
PubMed1990

Adult embryonal rhabdomyosarcoma of the vagina complicating pregnancy: a case report and review of the literature.

Embryonal rhabdomyosarcoma of the vagina in adults per se is uncommon and pregnancy complicated by such tumors is extremely rare. We wish to report one case of vaginal embryonal rhabdomyosarcoma, diagnosed at the age of 23 years who was carrying at the time of initial presentation. The problem of management of rhabdomyosarcoma in adults, particularly when they are associated with pregnancy is discussed. We advocate the use of multiagent chemotherapy and pelvic radiotherapy in its overall management.

Adult↗
PubMed1990

Skeletal metastases in carcinoma of the uterine cervix--a report of two cases and review of literature.

Occurrence of skeletal metastases in carcinoma of uterine cervix is infrequent. There are only a few cases who present wits osseous involvement at the time of initial diagnosis. Appearance of skeletal metastases in carcinoma uterine cervix is an ominous sign of progression of disease. Screening studies for detection of occult skeletal metastases in asymptomatic patients are not recommended.

Adult↗
PubMed1989

Effects of L-thyroxine and L-triiodothyronine on protein and nucleic acid contents of liver of 6N-2-propylthiouracil treated hypothyroid singi fish, Heteropneustes fossilis bloch.

Three consecutive injections of 12.5 X 10(-10) and 25 X 10(-10) moles/g of L-thyroxine (T4) or a single injection of L-triiodothyronine (T3) at 7.5 X 10(-10) moles/g to Singi fish caused an increase in liver protein and RNA contents, whereas similar injections of 50 X 10(-10) moles/g of T4 or 75 X 10(-10) moles/g of T3 caused a fall in these cellular constituents in liver. Treatments of Singi fish with thiourea (1 mg/ml) for 30 days caused a fall in the protein and RNA contents in liver which were restored to the euthyroid control level by a single injection of 7.5 X 10(-10) moles/g of T3 or three consecutive injections of T4 at 12.5 X 10(-10) moles/g dose. Administration of T4 (12.5 X 10(-10) moles/g, three consecutive injections) along with 6N-2-propylthiouracil (PTU) at 20 micrograms/g of b. w. in six consecutive injections to the thiourea treated (hypothyroid) fish failed to cause any change in hepatic protein and RNA contents in comparison to only PTU-treated hypothyroid fish, but a single injection of 7.5 X 10(-10) moles/g of T3 to the PTU-treated hypothyroid fish increased these cellular constituents of liver. A dose-dependent biphasic nature of thyroid hormone action, a higher potency of T3 than T4 and the probable 'prohormone' nature of T4 have been documented in case of Singi fish in the present experiments.

Animals↗
PubMed1989

Age-related changes of glycogen metabolism in human fetal heart.

The changes in the activities of three important glycogen metabolising enzymes, viz. glycogen synthetase, glycogen phosphorylase and alpha-D-glucosidase, along with glycogen content have been measured in adult human heart and human fetal heart collected at 13-36 weeks of gestation. At an early period, particularly 13-16 weeks of gestational age, the activity of glycogen synthetase and glycogen content were found to be maximum. However the activity of glycogen phosphorylase remained constant throughout the gestation and that of alpha-D-glucosidase showed a peak at 25-28 weeks of gestation, thereby indicating that fetal heart tissue has the capacity to utilise glycogen for energy.

Adult↗
PubMed1988

Demonstration of hepatic cytosolic malic enzyme activity as a thyroid hormone sensitive physiologic parameter in a teleost, Heteropneustes fossilis bloch.

Single injections of various doses (0.1, 0.25, 0.5, 5 and 20 micrograms/g) of T3 significantly increased the cytosolic malic enzyme activity (delta OD/min/mg cytosolic protein) in liver of Singi fish Heteropneustes fossilis Bloch, in a dose-dependent nature, maximum up to 5 micrograms/g dose on the 3rd day in comparison to the control. There was no difference in the enzyme activity between 5 and 20 micrograms/g of T3 doses. When the enzyme activity was expressed per mg DNA, the dose-dependent increase in the malic enzyme activity was observed upto 0.5 microgram/g of T3, whereas a fall in the enzyme activity was noticed with 5 and 20 micrograms/g of T3 doses. Lowering the dose of T3 to 0.05 microgram/g was without any effect on the malic enzyme activity (delta OD/min/mg cytosolic protein or DNA). Hepatic cytosolic protein content showed a biphasic nature of variation, significant increase with single injections of 0.05, 0.1, 0.25 and 0.5 microgram/g and a fall with 5 and 20 micrograms/g of T3 doses in comparison to the untreated control. Cycloheximide treatments of the Singi fishes counteracted both the T3-induced rise in the hepatic cytosolic malic enzyme activity (delta OD/min/mg cytosolic protein or DNA) and the hepatic cytosolic protein contents. Thiourea-treated hypothyroid fishes showed significantly decreased level of malic enzyme activity (delta OD/min/mg cytosolic protein or DNA) and cytosolic protein content in liver. A single injection of T3 at 0.25 microgram/g to the thiourea-treated fishes not only recovered but also increased the enzyme activity and cytosolic protein content above the untreated control values.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗