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Biomedical subjects

A D Webster

Publications and source records attributed to A D Webster.

At least 199 records · Page 11Linked to original sources
PubMed1981

Autoimmune blood dyscrasias in five patients with hypogammaglobulinemia: response of neutropenia to vincristine.

Five patients with autoimmune blood dyscrasias and primary hypogammaglobulinemia are described. The autoimmune neutropenia in two patients rapidly responded to vincristine but was resistant to steroids. The three patients with autoimmune hemolytic anemia responded to steroids. Vincristine is therefore the drug of choice in patients with autoimmune neutropenia and hypogammaglobulinemia and is preferable to a trial of steroids in severely ill patients. Two of the patients had increased numbers of circulating T suppressor cells for in vitro immunoglobulin production. It is therefore unlikely that the autoimmunity in these patients is based on a lack of such suppressor cells.

Adolescent↗
PubMed1981

Coeliac disease with severe hypogammaglobulinaemia.

A patient with severe late onset primary hypogammaglobulinaemia developed coeliac disease. The case illustrates that coeliac disease can occur in the virtual absence of local antibody production by plasma cells in the mucosa of the small bowel. Furthermore, our inability to demonstrate specific cellular immunity to a subfraction of gluten raises doubts about the relevance of immunological reactions in the pathogenesis of coeliac disease.

Agammaglobulinemia↗
PubMed1981

Recurrent chest infections, ciliary abnormalities and partial complement deficiency in a Jordanian family.

Four girls born to second cousin parents developed chronic chest infection and bronchiectasis in infancy. Three were studied in detail: they all had the same HLA haplotype, all showed random orientation of cilia or compound cilia in the respiratory tract, and all had low levels of the C1 and C2 components of the complement system. Although the cause of the respiratory disease in this family remains unclear, it is suggested that the low C1 levels may have contributed to the disease in two of the children while the low C2 levels were artefacts and the ciliary abnormalities were secondary to chronic chest infection.

Bronchiectasis↗
PubMed1981

BCG'osis.

Explore the source record for details and available documents.

BCG Vaccine↗
PubMed1981

Studies on the kinetic properties and subcellular localization of adenosine diphosphatase activity in human peripheral blood lymphocytes.

Using a recently developed radioassay, the conditions for measuring adenosine diphosphatase (ADPase) activity in human lymphocytes were optimized. Kinetic studies showed that the activity was optimal at pH 8.0 and required 0.2 mM MgCl2. The Km of the enzyme for ADP was 0.03 mM. Analytical subcellular fractionation showed that the ADPase activity was distributed between the plasma membrane and mitochondria. Studies with the non-penetrating inhibitor, diazotized sulphanilic acid, indicate that plasma membrane ADPase activity is located on the external aspect of the cell. Polymorphonuclear leucocytes were found to have about three times the ADPase activity. Lymphocytes, therefore, have the ability to generate AMP on their surface which can be further metabolized to adenosine by ecto-5' nucleotidase. A role for this system is discussed.

Apyrase↗
PubMed1981

Two immunologically distinct forms of late-onset hypogammaglobulinaemia.

Most patients with late-onset bypogammaglobulinaemia have normal numbers of B cells. In addition, some of these patients have been shown to have circulating T cells which suppress immunolobulin production in vitro. From our present studies on a large series of patients it appears that these two findings distinguish two separate groups of patients. The majority of the patients have circulating B cells which are 'immature' in the sense that they produce IgM but very little IgG or IgA in vitro. These patients also fail to produce IgA in vivo but their T cells show normal function in vitro and normal T cell markers. Patients with the second form of the disease, including those with associated thymoma, have very few circulating B cells, and relatively preserved IgA production in vivo. In our series it was only this minority of patients whose T cells showed abnormal markers and increased suppressor activity in vitro.

Agammaglobulinemia↗
PubMed1980

Lymphocyte 5'-nucleotidase in primary hypogammaglobulinaemia and cord blood.

The 5'-nucleotidase (5'-N) deficiency on circulating mononuclear cells of patients with 'common variable' hypogammaglobulinaemia (CV-H) was shown to be the result of one or more of three factors: reduced T cell 5'-N activity, a reduced percentage of circulating B cells, and a low B cell 5'-N activity. A lack of circulating B lymphocytes, together with a low T cell 5'-N activity in some cases, was found to be responsible for the deficiency of lymphocyte 5'-N in patients with X-linked hypogammaglobulinaemia (X-H). The low levels of 5'-N activity in CV-H and X-H patients were not due to abnormal compartmentalization of the enzyme, altered enzyme kinetics, or the presence of a regulatory factor. Cord Blood B and T cells have a lower 5'-N activity than adult lymphocytes. The patient and cord blood data are discussed in relation to the stage of cellular maturity.

Adolescent↗
PubMed1980

Lymphocyte cyclic AMP levels in primary hypogammaglobulinaemia: lack of correlation with response to phytohaemagglutinin.

Normal levels of lymphocyte cyclic AMP were found in fourteen of fifteen patients with primary hypogammaglobulinaemia. One patient with adult-onset hypogammaglobulinaemia had low cyclic AMP levels with a very poor rise after prostaglandin E1 stimulation. Five of the patients had severely depressed thymidine uptake by their phytohaemagglutinin-stimulated lymphocytes but there was no significant difference between their lymphocyte cyclic AMP levels and those of patients with normal lymphocyte responses. Removal of monocytes from concanavalin A-stimulated lymphocyte cultures from three of these patients did not affect the severe depression of leucine uptake. These findings indicate that the depression of lymphocyte response to mitogens seen in some patients with late-onset primary hypogammaglobulinaemia is not due to raised levels of lymphocyte cyclic AMP; and not usually due to prostaglandins released by monocytes in the cultures.

Adult↗
PubMed1980

Functional 'immaturity' of isolated B cells from patients with hypogammaglobulinaemia.

The membrane characteristics and in vitro function of the circulating B cells from patients with late-onset hypogammaglobulinaemia (CVID) and from patients with sex-linked hypogammaglobulinaemia (XLA) have been investigated using ox red blood cells coated with goat anti-human Ig. All seven patients with XLA had less than 2.0% SmIgM + ve cells and attempts to isolate these cells were unsuccessful. The majority of the 27 patients with CVID had greater than 3.0% SmIgM + ve cells. When cultured either with normal T cells and pokeweed mitogen (PWM) or with Epstein-Barr virus (EBV), isolated SIg + ve cells from eight patients with CVID produced significantly less IgM than normal cells and very little IgG or IgA. They also proliferated less well than normal cells and this correlated with IgM production. Stimulator capacity in the mixed lymphocyte reaction was normal in four out of seven cases. These properties of SIg + ve cells in the blood of patients with CVID are very similar to those of the normal 'immature' B cells found in adult bone marrow.

Agammaglobulinemia↗
PubMed1980

Phosphorylation of deoxyguanosine by B and T lymphocytes: evidence against selective trapping of deoxyguanosine by T lymphocytes in purine nucleoside phosphorylase deficiency.

T and B lymphocytes from blood and tonsils, as well as T and B lymphoid cell lines, phosphorylate deoxyguanosine which is probably the major toxic metabolite in purine nucleoside phosphorylase (PNP) deficiency. T and B cells also have similar activities of purine nucleoside phosphorylase. These findings indicate that the selective T cell defect in patients with PNP deficiency is unlikely to be due to a selective 'trapping' of deoxyguanosine by T lymphocytes.

Adenosine Deaminase↗
PubMed1980

Immune function in patients with extrahepatic portal venous obstruction and the effect of splenectomy.

Abnormalities of cell-mediated immunity-anergy to delayed hypersensitivity skin testing, diminished T-lymphocyte concentrations and mitogen responsiveness, and the presence of serum inhibitors--have been shown to be present in patients with portal venous obstruction and normal hepatic function. In contrast, tests of humoral immunity--antibody titiers to viral and bacterial antigens and immunoglobulin concentrations--were normal. These abnormalities in cell-mediated immunity are probably the result of the development of portal hypertension, portosystemic shunting, and congestive splenomegaly. These studies raise the possibility that qualitatively similar defects in patients with chronic liver disease and portal hypertension may, in part, be attributable to the same mechanisms.

Adolescent↗
PubMed1980

T lymphocyte subpopulations and Ia-positive T cells in patients with immunodeficiency.

T lymphocyte subpopulations (T gamma and Tmu) were studied in a group of 36 adult patients with immunodeficiency. Proportions and numbers of Ia(+) T cells were also studied in comparison to 46 normal adult controls. Values for per cent and total numbers of T gamma and Tmu cells indicated no uniform abnormality. Mean normal percentage of Ia(+) T cells was 2.4% whereas 16 to 29 immunodeficient patients showed elevated proportions and absolute numbers of Ia(+) T cells. Striking fluctuation in proportions of Ia(+) T cells was noted in serial studies of five immunodeficient subjects in contrast to similar analyses of normal controls. A correlation (P less than 0.01) was recorded between absolute numbers of Ia(+) T cells in immune deficiency patients and numbers of T mu cells. Depletion of T gamma cells by EA rosetting in patients with late-onset primary acquired hypogammaglobulinaemia did not result in significant change in IgG or IgM synthesis with T gamma-depleted T cells were co-cultured with normal B cells. Depletion of Ia(+) T cells likewise did not significantly influence Ig synthesis in co-culture with normal or immune-deficient B cells. These studies emphasize the complexity of defects present among any large group of patients with immune deficiency.

Adult↗