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Biomedical subjects

S Meng

Publications and source records attributed to S Meng.

At least 55 records · Page 3Linked to original sources
PubMed1994

Thyroid hormone responsiveness is developmentally regulated in the rat small intestine: a possible role for the alpha-2 receptor variant.

Thyroid hormone (T3) alters gene expression through binding to a receptor protein located within the nucleus of target cells. Multiple forms of the T3 receptor (TR) have been identified and are encoded by the alpha and beta c-erbA genes. We have previously found that TR beta-1 is the major receptor form expressed in the adult rat small intestine, although there are also moderate levels of c-erbA alpha-2, a nonhormone-binding variant that is thought to inhibit T3 action. In developing rats, we studied the regulation of two small intestinal enterocyte genes previously shown to be T3 responsive, lactase and 3.0-kilobase intestinal alkaline phosphatase (IAP). Animals were treated with six daily ip injections of either saline (control) or 30 micrograms/100 g BW T3 (T3 group) and killed at 10 and 25 days of age. Northern analyses of RNA derived from intestinal tissues showed that the magnitude of the T3-induced changes in lactase and IAP gene expression increased with development. Jejunal 3.0-kilobase IAP messenger RNA (mRNA) levels were unaffected by T3 at 10 days, but increased by 15-fold at 25 days. Similarly, jejunal lactase mRNA levels were unchanged by T3 at 10 days, but decreased by 75% at 25 days. Qualitatively similar results were seen in the duodenum and ileum. Studies of TR expression revealed that TR beta-1 mRNA levels were unchanged during the developmental period, whereas the levels of c-erbA alpha-2 decreased by 90% between 5-25 days after birth. These results indicate that the rat small intestine becomes increasingly T3 responsive during postnatal development. These changes occur in parallel with a decline in c-erbA alpha-2 levels, suggesting that this T3 receptor variant may play a role in this hormonal responsiveness.

Alkaline Phosphatase↗
PubMed1994

Bombesin maintains enterocyte phenotype in fasted rats.

BACKGROUND: Previous studies have suggested a relationship between enterocyte phenotype and the growth state of the epithelium; under atrophic conditions, lactase gene expression is high, whereas intestinal alkaline phosphatase (IAP) expression is low, and vice versa. On the basis of this model, we hypothesized that the intestinal trophic factor bombesin would alter brush-border enzyme gene expression in a predictable way. METHODS: Adult rats were fasted for 48 hours and treated (intraperitoneally) with either 10 micrograms/kg bombesin or the saline control every 8 hours. Small intestinal mucosal scrapings were taken, total RNA purified, and Northern blot analyses performed with radiolabeled cDNA probes corresponding to lactase, IAP, villin, and actin. Tissue samples were also taken for measurement of mucosal thickness. RESULTS: Bombesin administration caused an increase in jejunal mucosal thickness, thereby confirming its trophic effects. Bombesin resulted in a decrease in lactase mRNA levels and an increase in IAP mRNA levels along the length of the small intestine. No changes occurred in the expression of either villin or actin. The pattern of enterocyte gene expression in the bombesin-treated animals was similar to that in control-fed rats. CONCLUSIONS: Bombesin differentially regulates rat enterocyte gene expression, decreasing lactase and increasing IAP mRNA levels. These results lend further support to the hypothesis that a close relationship exists between enterocyte phenotype and epithelial growth state.

Alkaline Phosphatase↗
PubMed1990

[Experimental and epidemiological studies on the interrelationship of thiocyanate and thyroid function].

The testing of a SCN- dose (32 mg NaSCN/kg oral 21 d long) which is about 100 fold above the alimentary SCN(-)-uptake on guinea pig has shown neither histologic/morphometrical nor clinical clue to thyrostatic effect. In 6 regions of the GDR (1,349 persons) has not been secured epidemiologically any relationship between SCN- serum level as well as SCN- urine level and goiter. The partly in the tendency low increase of SCN- level by patients with bland goiter was always under the levels of smokers without goiter, exceeded indeed the threshold of significance in the area of Werdau. In the industrial agglomeration areas the I(-)-SCN(-)-quotient at the most unfavourable cases ran to 3.5 (Halle, smoker, struma), was consequently close to the critical level of the goiter risk.

Aged↗
PubMed1989

[TSH receptor antibody determination using the TSH radioreceptor antibody assay in clinical practice].

We tested the clinical valency of the TSH-receptor antibody (TBIAb) determination (TRAK assay, Fa. Henning) for the differential diagnostics of various diseases of the thyroid gland (n = 259), particularly of the hyperthyroidism. In 110 out of 114 basedowians TBAIAb could be proved (sensitivity 96%). The specifity to healthy persons (n = 20) was 100%, to the disseminated autonomy (n = 61) 92%. In 43 bland strumas and 22 cases of primary hypothyroidisms no circulating TBIAb were found. Of 40 cases of Basedow's hyperthyroidism the TBIAb titres were pursued during a 12-month methimazol therapy. In these cases was shown that negative antibody titres at the end of the treatment were connected with an essentially lower rate of early relapses than positive ones. Moreover, a highly dosed application of methimazol revealed a more favourable tendency than a low dosed one. From this we conclude that the TBIAb measurement with a commercial kit is a sensitive, sufficiently specific and practicable method for the differential diagnostics of hyperthyroidism and that to a certain degree it allows conclusions on the course of Basedow's disease after thyrostatic long-term therapy.

Autoantibodies↗
PubMed1988

N-acetylator phenotypes in hyperthyroidism.

Acetylator phenotypes were determined with sulfamethazine in 114 healthy volunteers, 87 patients with immunogenic hyperthyroidism (Graves' disease) and 38 patients with disseminated thyroid autonomies. About 90% of the patients were females. No significant differences of acetylator phenotypes were observed between female volunteers and hyperthyreotic patients younger than 50 years. The proportion of slow acetylators was higher in older patients. Early and late relapses did not depend on acetylator status.

Acetylation↗
PubMed1987

[Results of thyrostatic therapy of hyperthyroidism in patients with Basedow's disease and disseminated autonomy].

Up to now the results of drug treatment are unsatisfying. Treatment of more than 1-2 years did not decrease the occurrence of relapses. Thyroid suppression test and TRH test give the same indications concerning the outcome in cases with Graves' disease and disseminated autonomy (short-time prognosis). The relapse rate is distinctly higher in Graves' disease than in cases with disseminated autonomy (goitre class 3 excluded).

Follow-Up Studies↗
PubMed1982

[Results of thyroid hormone therapy in bland struma].

2,191 patients with bland struma were treated with tri-iodothyronine and a mixed preparation (thyreotom) for at least 2 years. Several clinical criteria were used for judgement. A good result could be obtained in 78.3 to 51.2% depending on the size of the struma (I-III). While in diffuse strumata good results were obtained in 87.8 to 69.0%, in nodular goitres we were successful only in 52.0-32.9%. The therapy may be successful at every age. Since with growing age the nodular goitres prevail, the chances of success become smaller. For the same reason there is a close correlation between age of the goitre and the therapeutic effect. The rate of success continuously decreases with growing age of the goitre. From this results that the therapy in goitre must begin early, before nodular and regressive changes, respectively, render the treatment difficult or render an acceptable result difficult.

Adult↗
PubMed1980

[Problems of treatment with thyroid hormones. Thyroxin monotherapy or a T3/T4 combination preparation?].

At the instance of T3- and T4-measurements of the daily profile in the serum after the application of triiodothyronine and the usual T3/T4-combination preparations is referred to the unphysiologically high T3-peaks 2 to 4 hours after the application depending on the proportion of triiodothyronine. The three distributed all over the day doses of e.g. thyreotom do not sufficiently smooth such undulations. The lacking triiodothyronine serum peaks after application of pure thyroxin as a bolus confirm the demand of a thyroxin monotherapy. Nevertheless, for answering the question of the "physiologic thyroid hormone therapy" some problems remain open which are discussed. Taking into consideration these facts (particularly conversation and extrathyroid influence of the thyroid hormone metabolism) a combination of T3 to T4 in the ratio 1:10 is recommended.

Adult↗