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Biomedical subjects

S Koch

Publications and source records attributed to S Koch.

At least 163 records · Page 9Linked to original sources
PubMed1991

Production of antibodies to the constant region of the mouse T-cell-receptor beta-chain.

To generate antibodies to the constant region of the mouse T-cell-receptor beta chain, the corresponding cDNA clone 86T5 was subcloned into the bacterial expression vector pEX2. The induced hybrid protein consisting of a 30 kDa T-cell-receptor segment and a beta-galactosidase carrier moiety was used for immunization. In Western blots using lysates of a T-cell-receptor-positive T-cell hybrid, the antisera obtained reacted with a 42 kDa protein under reducing and a 85 kDa protein under nonreducing conditions. The antisera did not react in binding assays with intact T lymphocytes, i.e. membrane-associated T-cell-receptor protein.

Animals↗
PubMed1991

[Tay-Sachs disease: a case report].

After an infection of the respiratory tract at the age of one a male infant showed progressive mental and physical retardation. Outstanding signs (e.g. baby doll face, startle reaction and frog position) as well as results of special investigations (cherry red spots of the maculae, short tubular bones) were suspicious for the presence of a lipidstorage disease, that could be identified as Tay-Sachs disease because of absent hexosaminidase A-activity in the patient's serum. Inspite the very low incidence of Tay-Sachs disease in our population, compared with a frequency of 1: 1200 in Ashkenzi Jews, the importance of establishing a diagnosis, based on typical clinical features and biochemical results, has to be emphasized. Genetic consultation is the only point of influence in positive family history, for attempts of causal therapy are not successful at present.

Brain Stem↗
PubMed1990

Synthesis of 19-nor-aldosterone, 18-hydroxy-19-nor-corticosterone and 18,19-dihydroxycorticosterone in the human aldosterone-producing adenoma.

The recently synthesized 18-C-steroid derivative, 19-nor-aldosterone(19-nor- aldo) and 18-hydroxy-19-nor-corticosterone(18-OH-19-nor-corticosterone) possess mineralocoroticoid and hypertensinogenic activity. They and an additional newly synthesized steriod, 18,19-dihydroxycorticosterone[18,19(OH)2-corticosterone], may play a role in the etiology and pathogenesis of disorders thought to be caused by steroids with mineralocorticoid and hypertensionogenic properties. In this study we provide evidence that 19-nor-aldo, 18-OH-19-nor-corticosterone and 18,19(OH)2-corticosterone are produced in vitro by aldosterone-producing adrenal adenomas and adenomas and adenoma of Cushing's syndrome. "silent" adrenal adenomas and the adjacent adrenal tissue. Measurable amounts of these steroids were found in the incubation fluids of adrenal tissues using specific RIAs performed after a sequence of HPLC systems. The rates of production of the three steroids were high in the aldosterone-producing adrenal adenomas and in adrenal hyperplasia compared with in either Cushing's adenoma or "silent" adenoma.

18-Hydroxycorticosterone↗
PubMed1990

Glucocorticoid hormones reduce the expression of major histocompatibility class I antigens on human epithelial cells.

Expression of a critical level of major histocompatibility complex (MHC) class I antigens on epithelial cells is a prerequisite for the action of specific cytolytic immune response cells. Glucocorticoid hormones have strong immunosuppressive effects. Therefore, we investigated the influence of the synthetic glucocorticoid dexamethasone on the expression level of MHC class I antigens on human epithelial cell lines. Long-term treatment with dexamethasone leads to reduced MHC class I surface antigen expression and to decreased total membrane-bound MHC class I protein. The steady-state mRNA level is significantly decreased and the transcription rate of MHC class I genes is reduced.

Cell Line↗
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

[Prenatal development and postnatal morbidity of newborn infants of HIV positive mothers].

Does the maternal HIV-infection itself influence fetal development and neonatal morbidity or are adverse effects related to maternal opiate and nicotine abuse? 17 neonates of HIV-positive women (7 drug users) and 37 controls (17 healthy and 21 opiate exposed newborns) were examined prospectively. A discriminant analysis showed that opiate and nicotine abuse during pregnancy were associated with fetal growth retardation and neonatal morbidity, while HIV-infection of the mother did not influence these parameters. Symptoms of an HIV-embryopathy were not seen.

Birth Weight↗
PubMed1990

[The importance of the endogenous agent and environmental factor thiocyanate for nonspecific and specific resistance from the hygienic viewpoint].

Thiocyanate (previous designation rhodanide, SCN-) is a physiological substance which is ubiquitously spread in the animate nature. As an essential constituent of cell it participates in important physiological resp. biochemical processes. From the hygienic and microbiological point of view the occurrence of SCN- as environmental factor, its alimentary significance and its vitalizing effect (stimulation of nonspecific and specific warding off, stimulation of proliferation, protective effect at toxic loading) are of interest for the fundamental and applied research.

Animals↗
PubMed1990

[Promotion of hair growth with thiocyanate in guinea pigs].

The advancement of growth of albino guinea pig hair has been induced by sodium thiocyanate through oral application (32 mg/kg) and more distinctly through balneological use (0.3, 5 resp. 10 g/l). The density of the hair has been increased at 6-38%, the longitudinal growth advanced at 2-14% and the phases of follicle cycle have been changed on behalf of anagenic hair at 11-39%.

Administration, Oral↗
PubMed1989

A simplified solid-phase assay for the quantitation of native membrane proteins. Application to the measurement of EGF receptor induction by dexamethasone.

Direct application of membrane fractions to a nitrocellulose support without previous solubilization, denaturation or fixation of the antigen permits the quantitation of antibodies binding to denaturation sensitive epitopes. In experiments reported here, this method was used to determine the rate of EGF receptor expression on squamous carcinoma cell lines. The assay revealed that dexamethasone treatment leads to an eight-fold increase of EGF receptor protein expression on C4-I cervical carcinoma cells. The data, when compared to the results obtained in immunoprecipitation experiments, suggest that this simple protocol yields reliable and precise quantitative data. The simplicity of the method permits simultaneous testing of large sample numbers with various antibodies.

Carcinoma, Squamous Cell↗
PubMed1989

Determination of urinary 3-methoxy-4-hydroxyphenylethylene glycol and its conjugates by high-performance liquid chromatography with electrochemical and ultraviolet absorbance detection.

A simple method for the determination in urine of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) and its conjugated derivatives is described. After an extraction procedure similar to that described by Gaertner and Wiatr [J. Clin. Chem. Clin. Biochem., 18 (1980) 579] isocratic high-performance liquid chromatographic separation is performed. MHPG can be detected by either electrochemical or absorbance detection (278 nm). Free MHPG is determined directly, whereas MHPG sulphate and MHPG glucuronide are determined after enzymic hydrolysis. Since total MHPG, which represents the sum of these substances, is determined separately, a comparison of the results allows the effectiveness of the hydrolysis of the MHPG derivatives for each urine sample to be determined. For quantitation, the method of adding standard amounts of MHPG is used.

Chromatography, High Pressure Liquid↗
PubMed1989

Selective loss of beta 2-microglobulin mRNA in human colon carcinoma.

Expression of MHC class I antigens requires the intracellular assembly of HLA-A,B,C H chains and beta 2-microglobulin (beta 2m). We have investigated the expression of free H chain, beta 2m, and their mRNAs in tissue sections of colon carcinomas that were defective for the native two-chain molecule. In all of these tumors, beta 2m protein and mRNA were found to be completely absent from the neoplastic cells, whereas free H chains and their respective mRNAs were present in abundance in the tumor cell cytoplasm. The selective abrogation of beta 2m expression represents a unique mechanism leading to a complete loss of class I antigen surface expression in vivo.

Carcinoma↗
PubMed1989

[HIV infection in children of seropositive mothers].

Both resolved and still open questions are discussed. The natural course of HIV infection from the time at which a child becomes symptomatic is known. The incidence rate of HI-virus transmission to the child remains uncertain. Likewise the time of transmission and its cofactors as well as data about the incubation and latency periods remain open questions. The greatest problem thus, is the early and reliable definition of HIV infection. Initial results from prospective HIV-perinatal studies are presented, showing that a transmission rate between 20% and 40% is to be reckoned with.

Child, Preschool↗
PubMed1989

Rat glucokinase gene: structure and regulation by insulin.

The glucokinase gene is 15.5-kilobases long, appears to be present as a single copy, and contains 10 exons that range in size from 96 to 977 base pairs. The transcription start site was located 127 nucleotides upstream from the translation initiation codon. The 5' flanking DNA contains several regions similar to defined promoter elements. These include a probable "TATA box," an Sp1 binding site, and several elements related to liver-specific gene expression. In addition, we determined that transcription of the glucokinase gene increased at least 20-fold when diabetic rats were treated with insulin for 2 hr.

Animals↗