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Biomedical subjects

H Chapel

Publications and source records attributed to H Chapel.

47 records · Page 3Linked to original sources
PubMed1989

Complement system protein C4 and susceptibility to hydralazine-induced systemic lupus erythematosus.

21 patients with systemic lupus erythematosus induced by long-term treatment with hydralazine were investigated to see whether susceptibility to this syndrome was associated with deficiency of the classical pathway complement protein, C4. 16 of 21 (76%) patients had one or more C4 null (ie, non-productive) alleles compared with 35 of 82 normal subjects (43%). This difference was significant. The HLA-DR4 antigen, known to be in linkage disequilibrium with the C4B null allele, was also significantly more frequent in the patients (14 of 21 patients compared with 31 of 81 normal subjects). Susceptibility to hydralazine-induced lupus, as in idiopathic systemic lupus erythematosus, may depend partly upon genetically determined C4 levels.

Alleles↗
PubMed1989

Crossover study of immunoglobulin replacement therapy in patients with low-grade B-cell tumors.

A randomized crossover study of prophylactic immunoglobulin (IgG) therapy was performed in patients with chronic lymphocytic leukaemia (CLL) or non-Hodgkin's lymphoma (NHL). Twelve patients with hypogammaglobulinemia or a history of recurrent infections received infusions of IgG or placebo intravenously (IV) every 3 weeks for 1 year. They were then switched to the alternative preparation for another year. The number of serious bacterial infections was significantly less (P = .001; Mainland's cross-over method) in the months in which patients received IgG. Serious bacterial infections showed a trend to be associated with an IgG level less than 6.4 g/L (P = .046; Fisher's exact test).

Aged↗
PubMed1988

Immunoglobulin replacement therapy by self-infusion at home.

Twelve patients, ten with common variable hypogammaglobulinaemia and two with hypogammaglobulinaemia secondary to chronic lymphocytic leukaemia (CLL), have been taught to self-infuse their intravenous immunoglobulin replacement therapy. Follow-up of these patients has shown that regular self-infusion at home is feasible and safe. There have been no anaphylactic or other serious reactions. Excellent patient compliance results from greater convenience and control over their own lives, in addition to time and money saved by the hospital.

Adolescent↗
PubMed1987

A study of genetic linkage in schizophrenia.

Families with more than one member affected by schizophrenia were identified and their members were interviewed. Four standardized diagnostic definitions (PSE, DSM-III, ICD-9, Feighner) were applied to all subjects who were classified as schizophrenic or not schizophrenic according to each definition. Non-schizophrenic psychiatric disorders which have been shown to be familially associated with schizophrenia were also identified. Twenty blood markers were ascertained for all subjects and evidence of co-segregation with schizophrenia was sought. No selective segregation was found and therefore there was no evidence suggesting linkage or supporting a monogenic theory of transmission of susceptibility to schizophrenia.

Genetic Linkage↗
PubMed1987

Erythrocyte complement receptor type 1 (CR1) expression and circulating immune complex (CIC) levels in hydralazine-induced SLE.

Family studies were carried out to look at CR1 expression in 24 hydralazine-induced SLE patients (Hz Reactors), who had been off the drug for at least 1 year and were clinically well at the time of the study. Mean expression of CR1 was reduced by 27% in the group of hypertensives who had developed Hz-induced SLE compared with a group of 35 normal individuals. CR1 expression was also slightly reduced in the relatives of the Hz Reactors compared to the normal group. Using a solid-phase Clq binding assay, CIC levels were found to be elevated in the plasma of the Hz reactors and an inverse relationship was found between CR1 levels and CIC levels in this patient group. Both CR1 levels and CIC levels in Hz Reactors and normal individuals were constant over the 36 weeks studied. This study suggests that there is an association between an inability to deal efficiently with CIC and susceptibility to developing Hz-induced SLE.

Antigen-Antibody Complex↗
PubMed1986

Effect of beta-propiolactone--an inhibitor of HTLV III/LAV activity--on immunological analyses.

beta-Propiolactone (BPL) inactivates LAV/HTLV III, the retrovirus associated with acquired immune deficiency syndrome (AIDS). Addition to specimens from patients with suspected AIDS or antibodies to LAV/HTLV III could reduce any occupational risk to laboratory staff. This study demonstrates that BPL treatment does not significantly affect the immunological analyses commonly required on these patients, namely measurements of serum immunoglobulins, complement components C3 and C4 and other serum proteins, detection of autoantibodies and estimations of T lymphocyte subpopulations.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Anti-granulocyte opsonic activity and autoimmune neutropenia.

Sera from patients with unexplained neutropenia have been assayed for anti-granulocyte opsonic activity using a chemiluminescence technique which measures the metabolic response of human monocytes to antibody-coated granulocytes. This rapid and simple technique was more sensitive than indirect immunofluorescence in the detection of anti-granulocyte antibodies. Anti-granulocyte opsonic activity was detected in sera from 17 of 31 patients, suggesting that their neutropenia may have had an autoimmune basis. The opsonic activity of five of the 17 sera was increased when granulocytes were sensitized in the presence of fresh serum. Four of these sera bound IgM and C3b to granulocytes in the immunofluorescence test. Human IgG when added to the monocyte suspension medium inhibited monocyte response to IgG antibody-opsonized granulocytes. This inhibition was less when granulocytes were opsonized with sera containing IgM and complement granulocyte-binding activity. This observation may be relevant to the selection of neutropenic patients for therapeutic use of intravenous immunoglobulin.

Adolescent↗
PubMed1983

Meningococcal meningitis associated with persistent hypocomplementaemia due to circulating C3 nephritic factor.

Two teenage patients who presented with meningococcal meningitis were found to have persistently low C3 levels even after recovery. This was accompanied by circulating C3 nephritic factor, which persisted for more than 12 months in each case. Neither patient had evidence of partial lipodystrophy or of glomerulonephritis initially, although one patient subsequently developed mesangioproliferative glomerulonephritis following a second admission with pneumococcal pneumonia. It is possible that the generation of the nephritic factor was initiated during the presenting illness.

Adolescent↗
PubMed1978

Expression of immunoglobin G on blood lymphocytes in chronic lymphocytic leukaemia.

A sensitive rosette test utilizing antibody-coated red cells has been applied to the study of the immunoglobulins on the surface of blood lymphocytes in chronic lymphocytic leukaemia (CLL). Contrary to other reports, IgG has been found to be a common surface membrane immunoglobulin (SmIg) on CLL cells. The reasons for this variation are discussed. Evidence is presented to show that (a) the anti-IgG-coated erythrocytes really are detecting IgG and not a cross-reacting substance, (b) the IgG is intrinsic to the cell and not cytophilically bound and (c) Fc-binding and other artefacts have been excluded. Expression of Ig by individual cells was studied by using mixtures of fluorescein- and rhodamine-labelled red cells coated with various anti-Ig. Fifty-one cases of untreated CLL were tested and the lymphocytes of thirty-eight of these cases bore Ig of a single light chain type. These cases could be classified on the basis of their lymphocyte SmIg as follows: eighteen expressing M and D and G, eleven expressing D and G but not M, six expressing M and D but not G, and three expressing G alone.

Humans↗