Search PubMed⌕ Search

Biomedical subjects

A Fischer

Publications and source records attributed to A Fischer.

At least 721 records · Page 40Linked to original sources
PubMed1986

Impaired T8 lymphocyte-mediated suppressive activity in patients with partial Di George syndrome.

We have studied the in vitro B-cell maturation induced by pokeweed mitogen of lymphocytes from seventeen patients with partial Di George syndrome. These patients were characterized by a low number of T8(+) lymphocytes. They had normal immune functions with an increased level of serum IgE for most of them. These patients were investigated before the age of 1 month. In contrast to age-matched subjects, their lymphocytes were able to produce in vitro immunoglobulins, although the level of immunoglobulin production was lower than in adults. These data were explained by a lack of T-cell mediated suppressor activity normally found in newborns. There was a strong correlation between the low number of T8(+) lymphocytes and the magnitude of the in vitro immunoglobulin production by patients' cells. This was further demonstrated by the ability of residual T8(+) lymphocytes isolated from patients to normally suppress the PWM driven B cell maturation on a per cell basis. The defective T-cell mediated suppression progressively disappears within 5 months. It is possible that this phenomenon is secondary to a delayed differentiation of suppressor T-cells in patients with partial Di George syndrome.

Antigens, Surface↗
PubMed1986

A study of 25 patients with chronic granulomatous disease: a new classification by correlating respiratory burst, cytochrome b, and flavoprotein.

Twenty-five patients suffering from chronic granulomatous disease (CGD) and their families were investigated. Defects in the superoxide generating system were characterized at the level of the heme-containing cytochrome b and of the FAD-containing flavoprotein, both localized in the plasma membrane of granulocytes. It was confirmed that in most of the typical cases (18 of 22), the complete inability of superoxide generation was associated with the absence of detectable cytochrome b. Mothers but not fathers of such male patients were characterized by a diminished content of cytochrome b, confirming that the affected gene is localized on the X chromosome. In contrast, the granulocytes of four other typical patients (two female and two male) contained normal amounts of cytochrome b, whereas oxidative activity was absent. Since no abnormality of oxidative activity as well as of cytochrome b was found in granulocytes of the mothers and fathers of these patients, an autosomal recessive mode of inheritance of the disease is probable. The flavoprotein deficiency found in the granulocytes of four male patients was always associated with an absence of detectable cytochrome b. This could indicate a structural relationship between flavoprotein and cytochrome b (e.g., a flavocytochrome). Three further patients with mild X-linked CGD contrasted with the patients with severe or classic X-linked disease; the oxidative activity of their phagocytes was diminished but not absent, and the cytochrome b present, albeit in small amounts.

Adolescent↗
PubMed1986

Restriction of the in vitro anti-mannan antibody response by HLA-DQ molecules.

In humans, the in vitro antibody response directed towards mannan, a polysaccharide extracted from the cell wall of Candida albicans, has been previously shown to be dependent on the presence of T lymphocytes and monocytes. Evidence is now given for the existence of a genetic restriction governing this response since antibody production is achieved provided that monocytes and T lymphocytes on one side and monocytes and B lymphocytes on the other side are of the same origin. In order to delineate the restriction element governing these interactions, blocking experiments have been designed using well-defined monoclonal antibody, anti-HLA class II molecules. The results clearly indicate that the restriction element belongs to the HLA-DQ molecular series, as shown in T-cell proliferation and antibody production assays in the presence of either T cells or T-cell supernatants. Incubation of isolated cell populations (T, B lymphocytes and monocytes) with the monoclonal antibody have indicated that DQ determinants are involved in the mannan presentation by monocytes to T and B cells. The HLA-DQ mediated restriction of the in vitro immune response to mannan has been observed in all the subjects tested, suggesting that mannan epitopes are preferentially, or even only, recognized in association with an unique group of HLA-class II molecules, namely HLA-DQ.

Antibodies, Monoclonal↗
PubMed1986

Longitudinal study of 18 children with perinatal LAV/HTLV III infection: attempt at prognostic evaluation.

We performed a longitudinal study (mean follow-up 19.5 months, range 3 to 42 months) in 18 consecutive children with clinical symptoms of LAV/HTLV III infection. Twelve patients were born to mothers infected with LAV/HTLV III, and six were infected by blood products administered during the first weeks of life. Immunologic studies included lymphocyte markers, in vitro responses to mitogens and antigens with corresponding skin tests, and antibody response with isoagglutinins, post-vaccination antibodies, and Candida. A serologic profile of antibody to GP110, P18, and P25 LAV/HTLV III antigens by radioimmunoprecipitation assay was also performed. The antigen-induced proliferative responses were normal in 10 patients who had a stable course, but were profoundly impaired in eight others who died or had poor condition with opportunistic infections. These in vitro measurements were well correlated with antigen skin tests. An abnormal antibody response to antigens, a low level of isoagglutinins, and a peculiar profile of LAV/HTLV III antibodies were also frequently observed in these eight patients. These measurements appear to be of prognostic value because they were noticed soon after onset of clinical symptoms.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Specific binding of antigen onto human T lymphocytes.

Human T lymphocytes sensitized to Candida albicans (CA) were shown to proliferate in cultures induced with mannan, a ramified polysaccharide extracted from the cell well of CA. We presently describe that, when we used strongly labeled [3H]mannan, antigen-specific T blast cells were able to bind the labeled mannan on their membrane. The observations that irrelevant blast cells did not bind [3H]mannan, and that mannan-specific blast cells did not bind tritiated pneumococcal polysaccharide SIII, indicate the specificity of mannan binding. Mannan binding was reversible and saturable. Mannan binding on T blast cells was inhibited by preincubation with monoclonal antibodies to T3 but not to other T cell-related molecules. The characteristics of this receptor suggest its identity with the T cell receptor for antigen. The direct binding of mannan could be either due to a cross-linking of the receptor by multivalent mannan or to a recognition of mannan in association with HLA-DQ molecules, as suggested by partial blocking of mannan binding using anti-HLA-DQ monoclonal antibodies.

Adult↗
PubMed1986

Effect of neurotensin in the dumping syndrome.

The possibility that the gut peptide, neurotensin, may contribute to the dumping syndrome was investigated in 17 patients with a long history of dumping after a Billroth II gastrectomy for duodenal ulcer. After a test meal plasma levels of neurotensin were higher than in normal subjects, but no correlation to the severity of symptoms was found. In eight of the patients with meal-provoked dumping symptoms, intravenous infusion of neurotensin in relevant doses produced neither symptoms nor changes in blood glucose, blood pressure, or pulse rate. The apparent plasma half-life of neurotensin (t1/2 = 2.3 min) did not differ from that previously found in normal subjects. The results indicate that it is unlikely that neurotensin alone has a pathogenetic role in the dumping syndrome in gastrectomized patients.

Aged↗
PubMed1986

Defective complement receptors (CR1 and CR3) on erythrocytes and leukocytes of factor I (C3b-inactivator) deficient patients.

In view of a possible modulation of the C3b receptor (CR1) by its ligand, we studied a situation in vivo in which C3b is constantly present in the serum, i.e. the genetic factor I-deficiency. C3b and iC3b receptors (CR1, CR3) on peripheral blood cells, were analysed in three I-deficient (I-def.) patients, from two unrelated families. CR1 and CR3 were quantified by means of monoclonal antibodies, and functionally tested (phagocytosis of sensitized sheep erythrocytes (EIgG) or rabbit erythrocytes (Er), coated with C3b, and chemiluminescence (CL) induced by serum-opsonized zymosan). Erythrocyte CR1 levels were significantly lower in I-def. patients than in normal individuals. Monocytes and polymorphonuclear neutrophils (PMN) prepared at 4 degrees C, to prevent increase of CR1 expression in vitro, expressed low CR1 numbers. Monocytes prepared at room temperature showed a defective CR1-dependent phagocytosis and an impaired CL response, although their CR1 levels were found normal in these conditions. This discrepancy was also observed on phorbol myristate acetate (PMA)-activated cells. These CR1 abnormalities are likely to result from repeated interactions of CR1 with C3b molecules, which circulated in the serum of I-def. patients and were deposited onto their red cells. Although iC3b, the CR3 ligand, is not produced in I-deficient sera, monocyte CR3-dependent function (phagocytosis of unopsonized Er) was also found to be defective in two out of the three patients.

Child↗
PubMed1986

[LAV infections and the acquired immunodeficiency syndrome in infants].

The clinical and immunologic abnormalities of 7 infants with Lymphadenopathy Associated Virus (LAV) infection are reported. Indicative immune changes, positive anti-LAV serologic test and/or virus isolation led to the diagnosis. In a case with a particularly severe form of the disease, whose mother died from AIDS, serologic tests and virus isolation were negative. Beside a case associated with blood transfusion, the familial and ethnic context helped the diagnosis. Clinical and biochemical features were close to those in adult AIDS, including hepatosplenomegaly, polyadenopathy, a decreased absolute number of OKT4(+) lymphocytes and hypergammaglobulinemia. The importance of cellular and sometimes also humoral immune deficiency was highly variable. For 4 patients, the severity of the immune deficiency allowed the diagnosis of AIDS. Occurrence of such an infection in the first months of life suggests a fetomaternal viral transmission; however, a postnatal contamination cannot be ruled out. Long-term prognosis is difficult to assess. It depends, among other factors, on the importance of the immune deficiency.

Acquired Immunodeficiency Syndrome↗
PubMed1986

HLA-haploidentical bone marrow transplantation for severe combined immunodeficiency using E rosette fractionation and cyclosporine.

Eight patients with severe combined immunodeficiency received bone marrow cells from their HLA haplotype-identical fathers after bone marrow T cell depletion by rosetting with neuraminidase-treated sheep red cells. Because the method led to the infusion of a small percentage of T lymphocytes (0.1% to 0.3%), cyclosporin was given by continuous intravenous infusion for two months in order to prevent the occurrence of graft-v-host disease (GVHD). Three patients who did have residual nonfunctional T lymphocytes received busulfan and cyclophosphamide before transplantation. Engraftment was observed in seven patients, and severe GVHD was not seen. Two patients died early after the bone marrow transplantation because of prior infections, and a third died at day 90 from a B cell lymphoproliferative syndrome. The five other patients are doing well. Stable engraftment has been achieved with reconstitution of cell-mediated immunity in 5/5 and humoral immunity in 4/5 patients.

Adenosine Deaminase↗
PubMed1986

[Bone marrow graft: graft versus host reaction and rejection].

The graft versus host reaction (GVH) remains the major setback of allogeneic bone marrow transplantation. GVH is observed in more than 50% of HLA identical transplantations. GVH can occur as an acute or chronic syndrome. The severity is variable, the GVH being responsible for the death of 10 to 20% of transplanted patients. Cytotoxic T lymphocytes or helper T lymphocytes are able on their own to mediate the GVH reaction. These T lymphocytes are specific for minor histocompatibility antigens. Some of them are restricted to specific tissues such as the skin. The frequency of the GVH reactions is increasing with the age of the recipient, with the degree of HLA antigens incompatibility and with presence of viral infections in the host. Several ways of GVH reaction prevention have been used such as the use of Methotrexate or Cyclosporin A. T cell depletion of the bone marrow appears to be the most effective method, allowing the achievement of HLA mismatched bone marrow transplantation. However, bone marrow T cell depletion is associated in 10 to 20% of cases with graft failure. The rate of graft failure is extremely high for HLA incompatible bone marrow transplantations. This could be due to the lack of antirejection effect of donor T lymphocytes. Graft rejection is mediated by host residual immunity. Cytotoxic T lymphocytes and perhaps natural killer cells are the effector cells. Several procedures attempting at the prevention of graft failure are currently under investigation. They tend to block the host residual immunity either by increasing chemotherapy or total irradiation, by using lymphoid irradiation or by the in vivo infusion of monoclonal antibodies specific for lymphoid cells.

Bone Marrow↗
PubMed1985

[Outcome of coronary transluminal angioplasties followed by an occlusion].

Coronary occlusion is the most serious complication of percutaneous transluminal angioplasty. In 440 cases coronary occlusion occurred in 22 patients (5%). Treatment was coronary bypass in 12 cases mechanical recanalization in 7 cases and coronary bypass after unsuccessful mechanical recanalization in 3 cases. One patient died after mechanical recanalization and 9 (41%) had myocardial infarction confirmed by electrocardiography and angiography. The number of coronary occlusions increased initially but decreased with improvements in materials and techniques. It is concluded that coronary occlusion is a severe but rare complication of percutaneous angioplasty. Mechanical recanalization should be attempted, and in case of failure the patient should be referred for surgery. In the large majority of cases the outcome is benign.

Aged↗