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Biomedical subjects

G Koch

Publications and source records attributed to G Koch.

At least 361 records · Page 20Linked to original sources
PubMed1982

Differential requirement for B-memory and T-memory cells in adoptive antibody formation in mouse bone marrow.

During the secondary response of mice to T-dependent antigens, antibody-producing plaque-forming cells (PFC) appear not only in peripheral lymphoid organs, but also in the bone marrow. This bone marrow antibody formation is feeble after primary immunization. The capacity of bone marrow antibody formation is dependent on the presence of antigen-specific memory cells at the moment of secondary immunization. We investigated whether hapten-primed B memory, carrier-primed T memory or both B-memory and T-memory cells are required for the adoptive PFC response in the bone marrow to T-dependent hapten-carrier conjugates. Adoptive antibody formation in the bone marrow was found after transfer of hapten-primed spleen cells, but not after transfer of carrier-primed spleen cells or virgin spleen cells. Thus, B-memory cells are obligatory for adoptive antibody formation in the bone marrow, in contrast to T-memory cells. However, T-memory cells did facilitate the bone marrow PFC response mediated by the infused B-memory cells.

Animals↗
PubMed1982

Inhibition of mitogenic stimulation of human lymphocytes by protease released membrane glycopeptides.

Mitogenic stimulation of human lymphocytes was induced by different means including non-lectin mitogens. Independent of the mean of stimulation the proliferation of lymphocytes was significantly inhibited by protease released lymphocyte surface glycopeptides (LySP). These surface peptides may have regulatory functions in cell proliferation and in the onset of the immune response in vivo. They offer a new tool for the elucidation of the triggering mechanism in mitogenic stimulation.

B-Lymphocytes↗
PubMed1982

Studies on HeLa cells surface glycopeptides alterations in membrane structure during the cell cycle.

Limited exposure of intact HeLa cells to proteolytic enzymes results in the release of fragments of membrane glycoproteins in the form of glycopeptides. Enriched and partially purified fractions from these glycopeptides are potent inhibitors of protein synthesis in cell-free systems and in intact cells. A comparison of the in vivo and in vitro response revealed that a substantial proportion of protein synthesis in intact cells is resistant to inhibition. When HeLa cell surface glycopeptides (HSP) induced inhibition of protein synthesis was studied in synchronized cell cultures it was found that G1 phase cells are most sensitive to HSP. A cell cycle dependent alteration in the availability of HSP to protease release was also observed. Cells in S phase yield the greatest amount of HSP upon limited proteolysis. The data suggest that alterations in membrane structure at the termination of S phase result in a conversion of membrane glycoproteins from a protease sensitive to a protease resistant state.

Cell Membrane↗
PubMed1981

[Calcium and bone metabolism after jejunal bypass operation for alimentary obesity: model for a intestinally-conditioned disorder (author's transl)].

Jejuno-ileostomy was performed in eight women because of severe alimentary obesity. Their calcium phosphate and bone metabolism was studied an average of 31 months post-operatively. This revealed secondary intestinal hyperparathyroidism due to an artificial malabsorption syndrome. While most of the significant metabolic factors were within normal limits, examination of calcium balance and kinetics indicated a marked disorder of calcium and bone metabolism. Calcium balance averaged-138 mg daily, corresponding to a yearly loss of skeletal mass of 4-5%.

Adolescent↗
PubMed1981

[Microcephaly].

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Child, Preschool↗
PubMed1981

Assignment of LIPA, associated with human acid lipase deficiency, to human chromosome 10 and comparative assignment to mouse chromosome 19.

The genetics of lysosomal acid lipase (LIP) has been investigated in human-Chinese hamster and mouse-Chinese hamster somatic cell hybrids. Cellulose acetate electrophoresis of human fibroblast extracts demonstrated that LIP activity consists of three isozymes. A deficiency of LIP activity has been observed in Wolman's disease (WD), cholesterol ester storage disease (CESD), and I-cell disease (ICD); this deficiency was associated with only one LIP isozyme, LIPA. We have demonstrated concordant segregation between human LIPA and human chromosome 10 and its enzyme marker glutamate oxaloacetate transaminase-1 (GOT1) in cell hybrid clones. Previous evidence suggested the different mutations associated with WD and CESD to be in the structural gene which we assign to human chromosome 10, while a different gene, involved in the processing of LIPA, is altered in ICD. These results indicate that several types of gene products are involved in the final expression of LIPA. In mouse-Chinese hamster hybrid clones, mouse Lip-1 (homologous to human LIPA) was assigned to chromosome 19. Previously, mouse Got-1 has been assigned to chromosome 19. Thus, the LIPA-GOT1 linkage groups has remained intact during the 80 X 10(6) years of evolution that separates humans and mice.

Animals↗
PubMed1981

Effects of short-term and long-term treatment with cardio-selective and non-selective beta-receptor blockade on carbohydrate and lipid metabolism and on plasma catecholamines at rest and during exercise.

1. The effects on glucose and lipid metabolism and on plasma catecholamines at rest and during exercise, of 4 weeks treatment with non-selective beta-blockade (pindolol, 15 mg daily) and with cardio-selective blockade (metoprolol, 200 mg, and acebutolol, 500 mg, respectively) were compared in different groups of hypertensive men (mean age 37 years) by single blind cross-over technique. All patients continued the treatment with either metoprolol or acebutolol for another 12--14 months. 2. All antagonists reduced blood pressures and exercise heart rates in a virtually identical manner. Whereas lipolysis was similarly inhibited by both selective beta 1-antagonists and non-selective beta 1-beta 2-blockers, glycogenolysis in the muscle was inhibited only by non-selective beta-receptor blockade. 3. The inhibition of glycogen breakdown resulted in exercise hypoglycaemia and in increases of plasma adrenaline and ACTH, which probably reflect counter-regulatory mechanisms. No major metabolic changes occurred after 12--14 months compared with 4 weeks of treatment.

Acebutolol↗
PubMed1981

Hemodynamic changes after acute and long-term combined alpha--beta-adrenoceptor blockade with labetalol as compared with beta-receptor blockade.

The hemodynamic pattern in hypertension varies according to the age of the subject and the stage of the hypertensive disorder. In the early stage, both cardiac output and systemic vascular resistance tend to be elevated. Already at that stage, mild degrees of left ventricular function disturbance can be detected. Advanced stages are characterized by a hypokinetic type of circulation with subnormal cardiac output and considerably increased systemic vascular resistance. Both cardioselective and nonselective beta-receptor antagonists lower cardiac output and tend to raise systemic vascular resistance. Even left ventricular filling pressures tend to be higher. While these effects are most distinct in the acute experiment, cardiac output remains always depressed and systemic vascular resistance stabilizes often at a higher level, compared with pretreatment values, even during long-term therapy. The antihypertensive action of beta-receptor blockers appears to be mainly due to the reduction of cardiac output. Combined alpha--beta-adrenergic blockade lowers blood pressure predominantly by alpha-adrenoceptor-mediated reduction of systemic vascular resistance both when induced acutely and during long-term administration. Owing to its beta-adrenoceptor blocking component, the increase of cardiac output is abolished: cardiac output is maintained at pretreatment levels, as is left ventricular filling pressure. Since a well-balanced blockade of both alpha- and beta-adrenergic receptors counteracts the hemodynamic changes occurring in the course of hypertension and tends to restore cardiovascular dynamics towards normal, combined alpha--beta-adrenoceptor blockade appears to be one of the most logical and rational therapeutical approaches to hypertension.

Adolescent↗
PubMed1981

The mechanism of thymus-dependent antibody formation in bone marrow.

During the primary immune response of mice to i.v. administered thymus-dependent antigens the spleen is the major site of localization of antibody-producing plaque-forming cells (PFC). During the secondary response, on the other hand, large numbers of PFC not only appear in the spleen, but also in the bone marrow. By inducing B memory cells with a DNP-carrier complex and activating the DNP-specific B memory cells with the same hapten conjugated to a heterologous carrier, we show in this paper that B memory cells, but not necessarily T memory cells, must be present before booster immunization for PFC to appear in the bone marrow. The origin of the PFC that appear in the bone marrow during secondary type immune response was studied in parabiotic mice consisting of members congenic for the Igh-1 locus. From analysis of the allotype of antibodies produced by PFC in the marrow of such pairs of parabionts it appeared that antibody formation in bone marrow is dependent on the immigration into the marrow of B memory cells activated in peripheral lymphoid organs. Consistent with such a migration of activated cells, radioautographic studies in guinea pigs demonstrated an influx of newly formed mononuclear cells into the bone marrow via the blood stream during the first 3 days after intravascular antigen administration.

Animals↗
PubMed1981

Development of a preventive dental care programme for children and adolescents in the county of Jönköping 1973-1979.

Dental research the last two decades has created a basis for understanding the etiology, prevention and treatment of dental diseases. As a consequence, particular interest has been focused on the effect of prophylactic measures, efficiently organized and carried out, for various groups of individuals. However, it has proved difficult to organize systematic integrated preventive dental care for large parts of the population. The present paper describes in detail the development of integrated preventive dental care for children and adolescents in the County of Jönköping. Sweden, from 1973 to 1979. Based on the circumstances that existed before 1973 as regards e.g. personnel and the nature and content of the prophylactic measures, a description is made of the aims, methods, target groups, organization, financing and evaluation of a preventive dental care organization gradually developed for the age groups 0-16 years in the whole county (308,000 inhabitants; 4,000 individuals in each age-group). Important practical information as to the performance of the organization is given as well as examples of both basic preventive dental care programmes and supplementary programmes intended for individuals exhibiting a high prevalence of caries and gingivitis. As an effect of the programme instituted of remarkable improvement in dental health among children and adolescents has been achieved.

Adolescent↗
PubMed1981

Prevalence and distribution of gingivitis-periodontitis in children and adolescents. Epidemiological data as a base for risk group selection.

The aim of the present study is to analyze the prevalence and distribution of gingivitis and periodontitis in children and adolescents and thereby try to find guidelines for developing preventive programmes and selection of risk individuals. Gingival and periodontal data from 500 children, 100 children in each of the following age groups, 3, 5, 10, 15 and 20 years, constituted the material. About 50 per cent of the 3-year-olds and more or less all the children in the older age groups had visible plaque. The corresponding figures concerning gingival inflammation were 35 per cent of the 3-year-olds and 65 - 97 per cent of the older children and the adolescents. Pathologically deepend pockets were found in 17 per cent in the 15-year-olds and in 21 per cent in the 20-year-olds. Four individuals in the 15- and 20-year old groups showed clear signs of periodontitis. When the distribution of gingival inflammation and periodontal disease within the respective age groups was studied it was frequently found that a small number of children showed pronounud symptoms of disease. When the distribution of gingival inflammation within the dentition was analyzed it was found that in the primary dentition the highest prevalence of gingivitis was found at the lingual surfaces of the lower molars and the buccal surfaces of the upper molars. In the permanent dentition the highest prevalence of gingivitis was found on the molars of the upper and lower jaw. The prevalence of gingivitis increased on the proximal surfaces with increasing age. Concerning pathologically deepend pockets the occurrence in the 15-20-year-olds was restricted to the mesial surface of the first permanent molars.

Adolescent↗