Search PubMed⌕ Search

Biomedical subjects

J F Bach

Publications and source records attributed to J F Bach.

At least 343 records · Page 19Linked to original sources
PubMed1988

Adoptive T cell transfer of autoimmune nonobese diabetic mouse diabetes does not require recruitment of host B lymphocytes.

The autoimmune nonobese diabetic mouse, a model of human juvenile type I diabetes mellitus, exhibits features of both B and T cell autoreactivity against insulin-producing cells. Using the neonatal cell transfer model of the disease, which we have described previously, we have shown that B cell suppression of newborn recipients by anti-mu treatment did not affect the transfer of diabetes by means of T cells. B cell-depleted, purified T cells from diabetic adults were injected into newborns treated with either IR-52, a control rat myeloma protein, or LOMM.9, a rat anti-mouse mu-chain mAb. Both groups developed diabetes over a similar time scale. Although the pancreases in both groups showed massive infiltration by T lymphocytes, B lymphocytes, presumably recruited in the host, were present in the IR-52-treated group, whereas they were absent in the LOMM.9-treated group. Anti-mu-treated diabetic animals showed substantial B cell suppression in vivo and in vitro when compared with IR-52-treated controls. These results suggest that B cell autoreactivity is a secondary phenomenon that is unimportant during the effector phase of diabetes in nonobese diabetic mice.

Animals↗
PubMed1988

NMR study of a lymphocyte differentiating thymic factor. An investigation of the Zn(II)-nonapeptide complexes (thymulin).

Detailed investigations of a serum peptide (less than Glu1-Ala2-Lys3-Ser4-Gln5-Gly6-Gly7-Ser8-++ +Asn9) were carried out by 1H and 13C NMR spectroscopy to elucidate the structure of the complex formed with Zn(II), thymulin, which has been found to be active in vivo. These experiments were performed in dimethyl sulfoxide-d6 solution at different metal:peptide ratios. The results suggest the following conclusions. (i) The Zn(II) complexation corresponds to a fast exchange on the NMR time scale. (ii) The evolution of 1H and 13C NMR chemical shifts indicates the existence of two types of complexes: a 1:2 species associating two peptide molecules and one Zn(II) ion and a complex with 1:1 stoichiometry. The former is predominant for metal:peptide ratios below unity. (iii) In the 1:2 complex, Zn(II) is coordinated by the Ser4-O gamma H and Asn9-CO2- sites, while in the 1:1 complex, Ser8-O gamma H is the third ligand to the Zn(II) ion. The results are compared with those for the [Ala4] and [Ala8] analogues, and those for the complexes of thymulin with other metal ions (Cu2+ and Al3+) in terms of its biological activity. These comparative studies suggested that the 1:1 complex is the only conformation recognized by the antibodies.

Dimethyl Sulfoxide↗
PubMed1988

Cyclosporin-associated nephropathy in patients with autoimmune diseases.

Renal biopsy specimens were evaluated from patients with different autoimmune diseases treated with cyclosporin (CyA). Ten biopsies were done before CyA, 10 biopsies after low-dose (less than 7.5 mg/kg/day, initial dose or mean daily dose within the first month, respectively), and 9 after high-dose (greater than 7.5 mg/kg/day) treatment. Definite chronic CyA nephrotoxicity (cyclosporin-associated arteriolopathy and/or interstitial fibrosis striped form with tubular atrophy) was only present in the initial high-dose group. In this group a significant serum creatinine increase was noted and 8 of the 9 patients were hypertensive. No significant correlation was found between the severity of morphologic lesions and the mean daily dose during total treatment, cumulative dose, and duration of therapy. The morphologic changes in the low-dose group did not differ from the control biopsy specimens before CyA treatment. Based on these results, it can be concluded that major nephrotoxicity can be avoided by initial low CyA doses.

Adult↗
PubMed1988

Anti-suppressor effect of cyclophosphamide on the development of spontaneous diabetes in NOD mice.

In the NOD mouse, an autoimmune process beginning by 5 weeks of age with lymphocyte infiltration and destruction of insulin-secreting beta cells leads to overt diabetes which begins to appear by 11 weeks of age. Although there is a high incidence of insulitis by 10 weeks of age (greater than 80%) in both males and females, by 30 weeks of age diabetic symptoms have occurred in 53-80% of females and in 12-40% of males. Intraperitoneal injection of a high dose (200 mg/kg) of cyclophosphamide (CY) consistently induces the onset of diabetes in male and female NOD mice at an age when spontaneous diabetes rarely occurs. Spleen T cells from CY-induced diabetic mice are capable of transferring the disease into irradiated nondiabetic syngeneic recipients. This indicates that the diabetogenic effect of CY is not mediated by direct toxicity on pancreatic beta cells but is mediated by abrogation of a suppressor mechanism which may prevent activation of T cells responsible for the development of diabetes in the NOD mouse. Additionally, CY is only effective in NOD mice and not in F1 hybrids between NOD and other strains of mice. Thus, the potential beta cell aggressor mechanism is not present in these hybrids as it is in homozygous mice, which indicates that it is not under the control of dominant genes.

Age Factors↗
PubMed1988

Cellular aspects of myasthenia gravis.

Several cellular aspects were investigated in a large series of patients with MG. First, non-Ag-specific proliferation was tested by measuring the response to r-IL2. Thymocytes from most MG patients showed hyperactivity to r-IL2. Peripheral blood lymphocytes (PBL) from some patients also showed a high response to r-IL2. These responding patients were generally those tested before thymectomy, presenting a high anti-AChR Ab titer and a severe form of the disease. Second, Ag-specific proliferation of MG PBL was assayed using 8 synthetic peptides corresponding to selected domains of torpedo or human AChR. Only 2 peptides gave a positive response in a significant number of patients, essentially in those presenting high anti-AChR Ab titer. The first is located near the alpha-bungarotoxin binding site and the second is in a cytoplasmic domain, according to models predicting the AChR transmembrane orientation. The positive results were essentially obtained with the human peptides; the corresponding torpedo peptides were positive in very few patients. Both human and torpedo peptides which include a part of the alpha-bungarotoxin binding site were negative. Finally, although morphological abnormalities were clearly visible in thymic hyperplasia, no correlation could be established between the thymus type and the cellular proliferation either to r-IL2, or to the peptides. Overall, our data indicate that cell-dependent mechanisms participate in the pathogenesis of MG, but the level of their involvement deserves further investigation.

Humans↗
PubMed1988

POEMS syndrome presenting as systemic sclerosis. Clinical and pathologic study of a case with microangiopathic glomerular lesions.

A rare form of plasma cell dyscrasia characterized by the various association of polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes has been termed POEMS syndrome. The pathogenesis of the multisystemic features of this syndrome remains unclear. Herein is reported a case of POEMS syndrome with striking clinical similarities with scleroderma, and microangiopathic glomerular lesions, as well as diffuse perivascular non-amyloid deposits, which could explain certain features of the syndrome, including peripheral nerve demyelination. It is proposed that a pathogenic role might be played by a non-immunoglobulin vasculotoxic component.

Adult↗
PubMed1988

Effect of myasthenic patient sera on the number and distribution of acetylcholine receptors in muscle and nerve-muscle cultures from rat. Correlations with clinical state.

We studied the functional activities (FA) of sera obtained from 83 myasthenic patients on rat muscle cultures. Using the same sets of cultures, two parameters were evaluated after exposure to sera: residual fraction (RF) of acetylcholine receptors (AChR) coupled to 125I-labelled alpha-bungarotoxin (alpha Bgt) (81 sera) and the number of rhodamine labelled clusters (56 sera). Two types of culture were assayed: muscle alone and nerve-muscle cocultures (12 cases). In all combinations (fluorescence, radiolabelling, muscle alone and nerve-muscle cocultures), we found a significant correlation between FA and antibody (Ab) titre, and no correlation between FA and clinical severity: only sera with a high or intermediate Ab titre were effective, whatever the clinical severity of disease. With active sera, AChR loss was about 50% whereas the disappearance of AChR clusters was quite complete, which suggests AChR redistribution induced by MG sera.

Animals↗
PubMed1988

In vitro inhibition of prostaglandin production by azathioprine and 6-mercaptopurine.

Although there are many data concerning the cytotoxic and immunosuppressive effects of antimetabolites such as azathioprine and 6-mercaptopurine, the mechanism of their antiinflammatory action has not been extensively investigated. In the present work, it is shown that azathioprine and 6-mercaptopurine (10-500 micrograms/ml) inhibit in a dose-dependent manner the production of PGE2, PGF2 alpha, 6-keto-PGF1 alpha and TXB2 by unseparated spleen cells as well as that of 6-keto-PGF1 alpha by adherent peritoneal macrophages. This inhibitory effect appears rapidly in vitro (within 15 min of incubation) and is observed in the presence of exogenous arachidonic acid (5 x 10(-6) M). The persistence of this effect in the presence of arachidonic acid, together with the fact that the production of four cyclooxygenase derivatives of acid arachidonic metabolism are inhibited, suggests that these drugs are acting at the cyclooxygenase level. The finding that cytotoxic and immunosuppressive agents, which act mainly by inhibiting RNA and DNA synthesis, can block prostaglandin production, may explain part of their antiinflammatory effects.

Animals↗
PubMed1988

Anti-histone antibodies in schizophrenia and affective disorders.

Sera from 81 psychiatric patients (51 with schizophrenia and 30 with affective disorders) were analyzed using several assays in parallel for the presence of non-organ-specific autoantibodies, namely anti-nuclear antibodies, anti-deoxyribonucleic acid antibodies (native and denatured DNA), anti-histone antibodies, anti-centromere antibodies, and anti-nuclear antigen antibodies. Nine out of the 81 sera studied were positive for the presence of anti-nuclear antibodies. Moreover, in 15 patients, significant titers of anti-histone antibodies were detected. No correlation can be drawn concerning the presence of anti-histone antibodies and the clinical situation. Although no clear association was noted with a specific class of drugs, it cannot be excluded at present that the therapeutic regimen received by the patients may explain the results observed.

Adult↗
PubMed1988

Prevention of diabetes in nonobese diabetic mice by anti-I-A monoclonal antibodies: transfer of protection by splenic T cells.

The nonobese diabetic (NOD) mouse has been developed as a model for insulin-dependent diabetes. One gene required for the development of diabetes is associated with the major histocompatibility complex. This gene possibly could be linked to class II genes, which show a unique pattern in NOD mice. To evaluate the role of the I-A class II antigen expressed in NOD mice, we studied the effect of anti-I-A monoclonal antibodies on disease onset in vivo. Long-term treatment with anti-class II IgG2a antibodies specific for NOD I-A antigen prevented the spontaneous development of diabetes, as opposed to control antibodies shown not to react with NOD I-A antigen. Anti-class II antibodies apparently elicited active immune suppression, requiring a fully immunocompetent host, rather than passive blockade of class II antigen. Treatment with anti-class II antibody effectively prevented the adoptive transfer of diabetes produced by splenocytes from diabetic NOD mice into newborn mice but failed to prevent adoptive transfer into irradiated adult NOD recipients. Direct evidence for the induction of suppressor cells was obtained from the passive transfer of spleen cells from anti-class II antibody-treated NOD donors. The injection of anti-class II antibody-treated spleen cells collected from NOD donors prevented the development of diabetes, which normally follows transfer of diabetogenic spleen cells into irradiated 8-week-old male NOD recipients. Depletion experiments indicate that CD4+ cells are responsible for anti-class II-induced protection transferred by spleen cells.

Animals↗
PubMed1988

One-month prophylactic use of OKT3 in cadaver kidney transplant recipients.

Fifty-five recipients of first cadaveric renal allografts were randomly assigned to three treatment groups in order to compare the safety and efficacy of a mouse antihuman T cell monoclonal antibody (OKT3) given prophylactically for a one-month period. This long period of administration was made possible by concomitant administration of azathioprine. The immune response against the foreign immunoglobulin was thus delayed and decreased in both intensity and severity, and OKT3 treatment could be given during almost the entire month in the majority of patients. The 18 patients who were enrolled in this treatment group had significantly (P less than 0.01) fewer rejection episodes during the first month posttransplantation than the 19 patients allocated to the high-dose (HD) steroid control group or the 18 patients allocated to the low-dose (LD) control group. Actual 2-year as well as actuarial 4-year graft survival rates were 89% in the OKT3 group, whereas they were 70% and 67% respectively in the steroid control groups. Four-year serum creatinine levels were normal and doses of steroids and other immunosuppressive agents were lower in the OKT3 group as compared with the control groups. Tolerance to OKT3 was good, and while viral infections were more frequently observed in OKT3 treated patients, the total number and the severity of infectious episodes were similar in all groups. The combination of one-month OKT3 plus azathioprine prophylaxis followed by conventional azathioprine plus low-dose steroid maintenance produced very satisfactory long-term results comparable to the best results now being obtained with cyclosporine regimens.

Adult↗
PubMed1988

Serum thymulin in human zinc deficiency.

The activity of thymulin (a thymic hormone) is dependent on the presence of zinc in the molecule. We assayed serum thymulin activity in three models of mildly zinc-deficient (ZD) human subjects before and after zinc supplementation: (a) two human volunteers in whom a specific and mild zinc deficiency was induced by dietary means; (b) six mildly ZD adult sickle cell anemia (SCA) subjects; and (c) six mildly ZD adult non-SCA subjects. Their plasma zinc levels were normal and they showed no overt clinical manifestations of zinc deficiency. The diagnosis of mild zinc deficiency was based on the assay of zinc in lymphocytes, granulocytes, and platelets. Serum thymulin activity was decreased as a result of mild zinc deficiency and was corrected by in vivo and in vitro zinc supplementation, suggesting that this parameter was a sensitive indicator of zinc deficiency in humans. An increase in T101-, sIg-cells, decrease in T4+/T8+ ratio, and decreased IL 2 activity were observed in the experimental human model during the zinc depletion phase, all of which were corrected after repletion with zinc. Similar changes in lymphocyte subpopulation, correctable with zinc supplementation, were also observed in mildly ZD SCA subjects. Inasmuch as thymulin is known to induce intra- and extrathymic T cell differentiation, our studies provide a possible mechanism for the role of zinc on T cell functions.

Adolescent↗
PubMed1988

Hashimoto's thyroiditis with a monoclonal antithyroglobulin autoantibody: disappearance of the monoclonal antibody after thyroidectomy.

A 46-yr-old man had typical Hashimoto's thyroiditis (HT) and a serum monoclonal immunoglobulin (MIgG kappa). There was no evidence of disseminated lymphoid malignancy. Because of rapid enlargement of the goiter with pressure symptoms, a total thyroidectomy was performed. The surgery was followed by the complete disappearance of the MIgG kappa paralleled by the disappearance of serum antithyroglobulin autoantibodies. Thyroid sections demonstrated HT. Direct immunofluorescence assay showed diffuse infiltration by lymphocytes and plasma cells that were mainly IgG kappa positive. Moreover, the serum MIgG kappa had antithyroglobulin activity, as demonstrated by two different methods, namely labeling of focused serum proteins with radioiodinated human thyroglobulin and immunoadsorption of the monoclonal IgG on a human thyroglobulin affinity column. These results demonstrate that a monoclonal antithyroglobulin autoantibody was produced within the thyroid in a patient with HT. As the production of a MIg is regarded as the last stage preceding the malignant transformation of normal B lymphocytes, this report strongly suggests that a B lymphoma can directly emerge from the intrathyroidal lymphocytes involved in the pathogenesis of Hashimoto's thyroiditis.

Antibodies, Monoclonal↗