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W Meng

Publications and source records attributed to W Meng.

At least 91 records · Page 5Linked to original sources
PubMed1994

Immunohistochemical characterization of monoclonal antibodies directed against the TSH receptor.

Monoclonal antibodies have been obtained by fusing mouse myeloma cells with spleen cells of mice immunized with crude thyroid membranes. Among the antibodies reactive with different thyroid antigenic components, three were found to specifically react with TSH receptor molecules. These antibodies displayed characteristic staining patterns on frozen sections of thyroid tissue from patients with various thyroid diseases upon identification of antibody binding by indirect peroxidase staining. No specific reactivity was detected with tissue from other human organs, such as pancreas, liver, fat, and muscle. The results demonstrate that the immunoperoxidase technique and the specificity of the monoclonal antibodies produced permitted the identification of cellular constituents that might be important antigens in autoimmune thyroid disease.

Animals↗
PubMed1994

Tissue regenerates of adrenal cortex with a physiological function twelve years after bilateral total adrenalectomy for Cushing's syndrome.

We report about a male patient, who underwent bilateral total adrenalectomy due to ACTH-dependent Cushing's syndrome without pituitary adenoma in his 11th year of life. Symptoms of Cushing's disease were absent during the follow-up period. Height and body weight followed the percentiles 25 and 50 respectively. An endogenous cortisol production was not detected and steroid substitution became necessary. Five years after the surgery, he showed normal cortisol levels, but there was no cortisol increase under ACTH-loading. Nine and 12 years (1993) after surgery, we found normal, physiological levels of cortisol suggestive of normal functioning adrenal glands (day profile of cortisol, Liddle-Test, ACTH-Test, CRH-Test, cortisol excretion in 24-h-urine). Moreover, baseline ACTH and its rise under CRH stimulation were normal. Scintigraphy revealed normal-sized adrenal tissue in orthotopic position on both sides. Steroid supplementation was discontinued. Presently the patient is healthy, active and under no steroid therapy. No evidence of residual or relapsing Cushing's disease or Nelson's syndrome has been found up to this point.

Adrenal Cortex↗
PubMed1994

Calcitonin gene-related peptide promotes cerebrovascular dilation during cortical spreading depression in rabbits.

We examined the role of calcitonin gene-related peptide (CGRP) in cortical spreading depression (CSD)-induced dilation of rabbit pial arterioles. In urethan-anesthetized rabbits instrumented with a closed cranial window, CSD induction with KCl dilated pial arterioles from 86 +/- 10 to 132 +/- 13 (mean +/- SE, n = 6) microns (a 54 +/- 9% increase). Topical administration of 12.8 microM CGRP-(8-37), a competitive inhibitor of the CGRP receptor, reduced CSD-induced pial dilation from 54 +/- 9% baseline to 33 +/- 9% (P < 0.05). Removal of the receptor antagonist from the brain surface restored CSD-induced dilation to 59 +/- 11% (P < 0.05, compared with the response with the antagonist present). In other animals, we showed that this dose of the CGRP antagonist attenuated arteriolar dilation to topically applied 10(-7) M CGRP (n = 5), but it did not alter arteriolar dilation to arterial hypercapnia. We also evaluated the dilator potency of substance P (SP) compared with CGRP. Dilation with 10(-7) M SP was only 22 +/- 11%, whereas arterioles dilated to 57 +/- 7% above baseline diameter with 10(-7) M CGRP. We conclude that CGRP contributes to the transient arteriolar dilation that is characteristic of CSD.

Animals↗
PubMed1994

Nitric oxide promotes arteriolar dilation during cortical spreading depression in rabbits.

BACKGROUND AND PURPOSE: Pial arterioles transiently dilate during cortical spreading depression (CSD), although the mechanisms are unclear. We tested the hypothesis that increased production of nitric oxide (NO) promotes arteriolar dilation. METHODS: Urethane-anesthetized rabbits were equipped with cranial windows, and the diameter (reported in micrometers) of a pial arteriole was determined via intravital microscopy. In each rabbit, a baseline CSD was elicited by microapplication of KCl onto the cortex, and resultant pial arteriolar dilation was measured. Either 100 mumol/L N omega-nitro-L-arginine methyl ester (L-NAME) or 50 mumol/L NG-nitro-L-arginine (L-NA), both competitive NO synthase inhibitors, was then applied to the brain surface. A CSD was elicited as before. The L-NAME and L-NA were then removed by artificial cerebrospinal fluid washes. An additional CSD was induced with KCl as before. RESULTS: Control CSD in the L-NAME group dilated pial arterioles; baseline diameter, 66 +/- 7 mm, with CSD = 106 +/- 8 mm (59% increase). After topically applied L-NAME, CSD dilated pial arterioles less: baseline diameter, 61 +/- 7 mm, with CSD = 77 +/- 6 mm (26% increase), P < .05 compared with control CSD diameter. Topical L-NA had similar effects on CSD: control CSD dilated pial arterioles 51%; after topical L-NA, only 14% (P < .05). After removal of L-NAME or L-NA, CSD-induced pial arteriolar dilation was similar to original control values. CONCLUSIONS: The reversible inhibition of CSD-induced pial arteriolar dilation by either L-NAME or L-NA suggests that NO contributes to arteriolar dilation observed with CSD.

Acetylcholine↗
PubMed1993

The kinetics of relaxin oxidation by hydrogen peroxide.

In this study, hydrogen peroxide was used to study the oxidation of rhRlx under various conditions. Oxidation of rhRlx occurred at both of the two methionines on the B chain, Met B(4) and Met B(25), as expected from the three-dimensional structure of the molecule, which shows that these two residues are located on the surface of the molecule and exposed to solvent. The reaction produced three different oxidized forms of rhRlx containing either Met B(4) sulfoxide, Met B(25) sulfoxide, or both residues oxidized. The corresponding sulfone was not formed under these conditions. The oxidation at the two methionines proceeded independently from each other but Met B(25) was oxidized at a significantly faster rate than Met B(4). The fact that the rate of oxidation at Met B(25) was identical to the rate of oxidation of free methionine and that of two model peptides mimicking the residues around Met B(4) and Met B(25) suggests that the lower reactivity at Met B(4) was due to steric hindrance, and at least in this case, neighboring groups do not influence the oxidation kinetics of methionine residues. The reaction was independent of pH, ionic strength, and buffer concentration in the range studied. The enthalpy of activation for the reaction was approximately 10-14 kcal mol-1, with an entropy of activation of the order of -30 cal K-1 mol-1. These data are consistent with previously published mechanisms for organic sulfide oxidation by alkyl hydroperoxides.

Amino Acid Sequence↗
PubMed1993

Retention of cerebrovascular dilation after cortical spreading depression in anesthetized rabbits.

BACKGROUND AND PURPOSE: We examined responses of rabbit pial arterioles to three different stimuli before and after induction of cortical spreading depression. METHODS: In urethane-anesthetized rabbits equipped with a closed cranial window, we measured pial arteriolar diameter during baseline conditions, topical application of calcitonin gene-related peptide (CGRP), topical application of acetylcholine, and inhalation of 10% CO2 in air (arterial hypercapnia) before cortical spreading depression and 30, 60, and 120 minutes after cortical spreading depression. Cortical spreading depression was induced by localized application of a 5% KCl solution anterior to the arteriole being measured. RESULTS: Average baseline diameter was approximately 90 microns. During cortical spreading depression, arteriolar diameter increased to a peak value that was 50 +/- 4% above baseline (n = 32). Before cortical spreading depression, arteriolar diameter changed 47 +/- 7% (n = 9) during hypercapnia, 17 +/- 3% (n = 4) during 10(-9) mol/L CGRP, 42 +/- 10% (n = 7) during 10(-7) mol/L CGRP, 29 +/- 6% (n = 4) during 10(-6) mol/L acetylcholine, and 61 +/- 13% (n = 6) during 10(-4) mol/L acetylcholine. Arteriolar responsiveness to any of these stimuli was not changed significantly by prior cortical spreading depression. CONCLUSIONS: Dilator capacity of pial arterioles is still intact in urethane-anesthetized rabbits after cortical spreading depression.

Acetylcholine↗
PubMed1993

Comparative effects of angiotensin-(1-7) and angiotensin II on piglet pial arterioles.

BACKGROUND AND PURPOSE: Recent investigations indicated that degradation fragments of angiotensins could be involved in the regulation of the cerebral circulation and that their effects might be mediated by prostaglandins. The present study was designed to examine the effect of angiotensin-(1-7), a major endogenous heptapeptide fragment, on cerebral arteriolar diameter and compare it with the octapeptide angiotensin II, and further to determine whether prostaglandins mediate their effects. METHODS: Newborn, anesthetized pigs were equipped with a closed cranial window, and the diameter of one pial arteriole was measured using intravital microscopy. RESULTS: Topical application of angiotensin-(1-7) (n = 9) increased the diameter by 6.8 +/- 5.3% (mean +/- SEM), 10.4 +/- 5.2%, 14.3 +/- 5.9%, and 17.5 +/- 7.7% (P < .05) at 10(-7), 10(-6), 10(-5), and 10(-4) mol/L, respectively (baseline, 94 +/- 3 microns). Topical application of angiotensin II (n = 8) increased the diameter by 9.6 +/- 7.0%, 9.6 +/- 7.6%, 11.3 +/- 8.4% (P < .05), and 5.5 +/- 7.9% at 10(-7), 10(-6), 10(-5), and 10(-4) mol/L, respectively (baseline, 94 +/- 5 microns). After administration of indomethacin (5 mg/kg IV), which did not significantly change the baseline arteriolar diameter, neither angiotensin-(1-7) at 10(-4) mol/L nor angiotensin II at 10(-5) mol/L caused significant vasodilation. CONCLUSIONS: The results indicate that angiotensin-(1-7) is a modest dilator in the cerebral circulation, as is angiotensin II, and that prostaglandins may mediate responses.

Angiotensin I↗
PubMed1990

[Bone alkaline phosphatase as an activity parameter of acromegaly].

Serum levels of growth hormone (GH: arithmetic mean of three measurements eight hours apart), somatomedin C (SmC), alkaline phosphatase activity and the bone isoenzyme of alkaline phosphatase (as the liver/bone isoenzyme ratio) were measured in 26 patients with acromegaly (11 men and 15 women; mean age 45.5 [24-66] years), 18 in the active and eight in the nonactive phase of the disease. Activity was characterized by a raised (660 [330-1149] ng/ml), inactivity by a normal (186 [40-300] ng/ml) SmC concentration. All 18 patients with active acromegaly had an abnormally low liver/bone isoenzyme ratio (mean of 0.66 [0.01-1.28]). In seven of the eight patients with inactive acromegaly it was within normal limits. Thus measurement of bone alkaline phosphatase, which is significantly cheaper than that of SmC, is suitable for assessing activity.

Acromegaly↗
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↗
PubMed1990

A 5 year interdisciplinary control of iodine deficiency in the GDR.

The interdisciplinary iodine prophylaxis in the GDR is a successful measure for control of ID. The iodization of nearly all the salt is planed perhaps with reduction of the iodine concentration. However, next further steps may be done in cooperation of the Interdisciplinary Iodine Commission with the "Arbeitskreis: Jodmangel" in the FRG.

Germany, East↗
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↗
PubMed1989

Interdisciplinary aspects of iodine prophylaxis in German Democratic Republic.

Endemic goiter still occurs in several European countries. Alimentary iodine deficiency could be proved as the main cause of endemic prevalence. Extensive epidemiologic surveys showed the great medical and economical impact of this matter for the GDR. Over 200 million Marks might be spent for diagnosis and treatment of thyroid patients per year. Also in the field of veterinary medicine and animal production iodine deficiency plays an important role. Under the conditions of iodine deficiency the fodder containing nitrate and glucosinolates (e.g. bruised rape extraction) results in additional goitrogenic effects (so-called indirect or relative iodine deficiency). Due to iodine deficiency disorders considerable losses of yields in cattle, pigs and sheep occurred. The content of iodine in animal products used for human nutrition was subsequently low. Considering the ecological implication of these problems an Interdisciplinary Iodine Commission within the Society for Endocrinology and Diseases of Metabolism of the GDR was established. Together with the governement authorities it worked out corresponding recommendations for the prophylaxis and control of its efficiency. In 1986 the iodination of most of the packed salt (32 mg KIO3/kg = = 19 mg I/kg) and the administration of iodinated mineral mixtures for the animal production were started for pigs in the whole territory of GDR and for cattle in the southern counties of the GDR only. These activities have been accompanied by information of TV as well as in the newspapers and medical journals. Thus, an improved supply of iodine to the population through iodinated table salt and animal products can be taken into account. The efficiency of these prophylactic measures is controlled interdisciplinarily.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗
PubMed1988

[Therapy of hyperthyroidism].

The symptoms called hyperthyroidosis are caused by a thyroid hormone intoxication, which may have various causes. More than 95% of the hyperthyroidosis are caused by an autoimmune thyropathy (Basedow's disease) or autonomy (autonomous adenoma, disseminated autonomy). Other causes are rare. The therapy has 2 aims: the normalisation of the supply of the thyroid hormone and the removal or influence of the cause. Thus apart from an exact functional diagnostics the etiopathogenetic coordination must be done which has an essential influence on the differential-therapeutic decision. Beside the general therapeutic measures the thyrostatic long-term therapy, the subtotal thyroid resection and the radioiodine therapy are at our disposal. Diagnosis, performance, advantages and disadvantages are demonstrated.

Humans↗
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

[Development and effectiveness of struma prevention in East Germany].

For the control of iodine deficiency disorders in man and animal since 1985/1986 measures have been introduced which were interdisciplinary attuned: 84% of the paketed salt are iodized (32 mg KIO3/kg) and iodized mixtures of mineral substances are used in the animal production of agricultural useful animals. The effectiveness of the iodine prevention becomes visible by an increase of the renal iodine excretion, regression of the frequency of connatal goitre and iodine deficiency disorders in the animal production. Increased manifestations of cases of hyperthyroidism as sequelae are of transient importance.

Goiter, Endemic↗