Search PubMed⌕ Search

Biomedical subjects

H Jahr

Publications and source records attributed to H Jahr.

At least 55 records · Page 3Linked to original sources
PubMed1989

[The liver--an immunologically privileged organ?].

Some rat strains permanently accept allogenic livers without pharmacological immune suppression. In the same donor/recipient combinations, other organs as heart, kidney or skin are normally rejected. The transplanted liver not only withstands its own rejection, but also induce donor-specific immune tolerance. The mechanisms responsible for this effect may be clonal deletion, activation of suppressor cells or immune suppressive circulating factors as anti-class II-antibodies. An "immune-privilege" of an orthotopically transplanted liver exists also in pigs and, however to a lesser extent, in other large mammalian species including man. Regeneration of liver tissue altered by the transplantation procedure may produce the signals for induction of tolerogenic mechanisms.

Animals↗
PubMed1988

Complement-mediated cytotoxic effects of islet cell surface antibodies in non-diabetic subjects with antecedent mumps infection and diabetic risk.

We studied sera of 24 selected non-diabetic subjects in whom an antecedent mumps infection with either complications and/or with onset at older age occurred 10-27 month ago regarding the capability to lyse rat islets of Langerhans in vitro. Thirteen subjects were characterized by diabetes associated HLA antigens DR3 and/or DR4 whereas 11 of them had none of these HLA antigens. Islet cell surface antibodies (ICSA) could be detected in 11 out of 24 subjects. Isolated pancreatic islets from 8-10 days old Wistar rats were incubated in freshly prepared human serum. The insulin leakage under the conditions of pharmacologic blockade of insulin secretion by means of epinephrine and propranolol provides a measure of complement-mediated cytotoxicity of human serum against rats islets in vitro. Out of a total of 24 subjects the sera of 11 of them exhibited cytotoxicity. Mean cytolytic insulin leakage was significantly higher in subjects with DR3 and/or DR4 in comparison with subjects without these HLA antigens (6.82 +/- 0.77% vs 3.90 +/- 0.48%; p less than 0.05). Ten out of the 11 subjects with cytotoxic sera had HLA DR3 and/or DR4 whereas DR3 was present in three out of 13 subjects with non-cytotoxic sera. There was no relationship between beta cell function in vivo (fasting C-peptide concentration and insulin response to oral glucose challenge) and the capability of patients sera to damage islet cells in vitro. In conclusion the pathogenetic role of mumps virus and cytotoxic ICSA and their possible relation to slow progressive beta-cell destruction has still to be ascertained.

Adolescent↗
PubMed1987

Prevention of complement-mediated cytotoxicity against rat islets by encapsulation in a cellulose sulphate membrane.

The immuno-isolation by semipermeable membranes should prevent the immunological destruction of the transplanted tissue. The polyelectrolyte complex membrane from cellulose sulphate and poly(dimethyldiallylammoniumchloride), which does not alter the viability of the encapsulated rat islets, can prevent complement-mediated cytotoxicity. The 51Cr release from prelabelled islets, which was induced by either unspecific cytotoxicity of rabbit sera against the rat islets or by an anti-MHC rat serum in presence of complement, was prevented. The diffusion of immunoglobulins as well as of factors of the complement system was inhibited by encapsulation. The capsule membrane also prevents the beta-cell destruction in cytotoxic sera from newly diagnosed type-I diabetics measured as insulin leakage after blocking the active hormone secretion. In conclusion, the cellulose sulphate membrane seems to be useful for the transplantation of encapsulated islets.

Animals↗
PubMed1986

[Activation of human granulocytes and monocytes by physiologic concentrations of thiocyanate (rhodanide)].

The lytic activity of human granulocytes or monocytes against hyperimmune-anti B-sensitized erythrocyte targets is enhanced after a twenty hours preincubation in the presence of physiological serum concentrations of thiocyanate. An analogous pretreatment of effector cells has no influence on antibody-dependent lymphocyte-mediated cytotoxicity. Concentrations of thiocyanate corresponding to those found in human serum are without any effects when the ion is added immediately before starting of cell-mediated erythrocyte lysis.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1986

[Determination of antibody-dependent cytotoxicity of granulocytes, monocytes and lymphocytes using human erythrocytes as target cells].

Antibody-dependent cell-mediated cytotoxicity of human blood leukocytes was determined by use of 51chromium labelled human erythrocytes as target cells. The lytic activities of granulocytes, monocytes and lymphocytes can be defined simultaneously without the need for a separation of mononuclear cells into subpopulations. Hyperimmune-anti B-serum and immunoglobulin-anti D(Rh0) (Dessau) were used as sources for antibodies. The human granulocyte is very effective in destroying antibody-coated target cells and should therefore not be neglected in clinical studies dealing with antibody-dependent cytotoxic reactions.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1986

[Hysteria and psychosis].

The relationship between endogenous-psychotic and hysterical behavior is presented in this paper on the basis of typical patients' accounts. Various patterns of behavior are revealed: chronic hysterical psychotic syndromes, acute hysterical psychotic syndromes, hysterical exalted psychotic episodes, simulated hysterical psychotic syndromes, hysterical behavior in the attempt to cope with psychosis, and pseudohysterical behavior in endogenous psychoses. The specific aspects of the doctor-patient relationship in the case of these patients are described.

Adaptation, Psychological↗
PubMed1985

The encapsulation of pancreatic islets. Investigation of insulin secretion and content in vitro.

Polyelectrolyte complex capsules from cellulose sulphate can be formed by precipitation in a polycation bath. The application of this new method for encapsulation of pancreatic islets requires investigations whether and to what extent cellulose sulphate injures viability and functionality of the pancreatic islets. Islets cultures in the presence of 2% cellulose sulphate for up to 3 weeks are characterized by unchanged insulin content, secretion and biosynthesis when compared to appropriate controls.

Animals↗
PubMed1985

[Results of short-term group psychotherapy of schizophrenic patients].

A seven-week group-centered dynamic therapy course was conducted with 12 patients within the framework of a long-term treatment for schizophrenic patients. The purpose and method of treatment and the course of the group sessions are described. Analysis of the Freiburg personality inventory yielded no changes; the degree of agreement between the group mean profile and that of neurotics was striking. Analysis of the Frankfurt complaint questionnaire (Suellwold) revealed a reduction in the number of affirmative answers during and after treatment. The treatment is considered to have had positive results, although it has to be embedded in a more comprehensive treatment plan with supportive individual psychotherapy, psychopharmaceutic treatment and sociotherapy.

Adult↗
PubMed1984

Insulin secretion in type II diabetics: in vivo and in vitro investigation.

Many cases of type II diabetes present an anomaly of insulin secretion which is characterized by a missing, reduced, or delayed glucose-stimulated insulin output from the beta cell. We aimed at finding out whether this characteristic disorder is a consequence of reduced beta cell mass or of a more functional disturbance. In the latter case it was to be clarified whether the disturbed beta cell "glucoreceptor" function represents a qualitative or rather a quantitative difference. By the evaluation of insulin secretion and of carbohydrate tolerance during oral and/or intravenous intake of glucose, and after intravenous application of tolbutamide or glucagon the defective insulin secretion in type II diabetics was found to represent a more functional disturbance which could not be explained by reduction of beta cell mass. Thus it was concluded that the anomaly of insulin secretion mentioned above might be a consequence of a qualitative defect of the glucoreceptor. To prove this, isolated human islets (insulin secretion under incubation with glucose, measurements of 3H-leucine incorporation and of the insulin content) were also studied. In contrast to the in vivo results, insulin release of the isolated islets of type II diabetics was normal. From this it must be concluded that the glucoreceptor of the beta cell, which in vivo reacts in a qualitatively different manner from that of subjects with intact metabolism, is not irreversibly disturbed.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1984

Cellular immune reactions against rat pancreatic islets mediated by antibodies from type I diabetic patients.

Serum samples from 13 newly diagnosed type I diabetics were tested for their ability to mediate antibody-dependent cellular immune reactions against pancreatic islets prepared from Wistar/Jena K rats. Nine of these serum samples proved able to mediate islet cell damage when the islets were preincubated with sera and then cultivated with leukocytes of healthy subjects for 20 h. Damage to islets was demonstrated both by the trypan-blue exclusion test and by measurement of insulin leakage during incubation. The data presented point to a possible pathogenetic role of antibodies mediating cellular immune reactions in type I diabetes.

Adolescent↗
PubMed1984

Complement-mediated cytotoxic effects of islet cell surface antibodies: factors influencing the sensitivity of the target cells.

Sera from 26 out of 34 newly diagnosed type I diabetic patients were cytotoxic to the beta cells of isolated rat pancreatic islet. The severity of beta cell lysis by cytotoxic sera was increased when the islets were preincubated for 20 h with clofibrate, actinomycin D, or tolbutamide. Preincubation of isolated islets with elevated glucose concentration decreased the sensitivity of the beta cells to humoral immune attack whereas glibenclamide had no effect. The sensitivity of target cells to complement-mediated cytotoxicity seems to be related to cellular lipid synthesis.

Animals↗
PubMed1983

Enhanced synthesis, storage, and secretion of insulin in pancreatic islets derived from obese subjects.

Insulin biosynthesis, content, and secretion were investigated in islets derived from pancreas specimens of normal weight (100.4 +/- 1.1% of ideal body weight) and obese (137.2 +/- 5.9% of ideal weight) patients. The pancreatic islets from the obese subjects were characterized by a significantly enhanced glucose-induced insulin secretion and biosynthesis and by an insulin content that was nearly double when compared with islets from the nonobese subjects. The results support the hypothesis that an enhanced beta-cell reactivity significantly contributes to the insulin hyperresponse observed in the obese state.

Adult↗
PubMed1982

Correlations between the presence of islet cell surface antibodies in human serum and the cytotoxic effects on rat islet beta-cells.

Isolated pancreatic islets from 7-10 days old Wistar rats were incubated in freshly prepared human serum. The cytotoxic insulin leakage from the islets was correlated with the presence in the sera of islet cell surface antibodies (ICSA) determined by indirect immunofluorescence. Such cytotoxic ICSA were found to be common in Type-I diabetics as well as in nondiabetic subjects who had contact with laboratory rats.

Animals↗
PubMed1981

[Causes of insulin secretion disorders in non-insulin dependent diabetics. Comparison of in vivo results with examinations of isolated islet cells].

Non-insulin dependent diabetics (NIDD) used in our experiments do not or in a small extend only respond to glucose; but glucagon and tolbutamide loads result in an increased insulin secretion. In contrast, pancreatic islets isolated from biopsies of the pancreas do not show any differences in insulin secretion, biosynthesis and content between NIDD and control groups. Some reasons of these differences between in vivo and in vitro results are discussed.

Aged↗