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Biomedical subjects

H M Chapel

Publications and source records attributed to H M Chapel.

At least 73 records · Page 4Linked to original sources
PubMed1987

Comparison of polyacrylamide and agarose support media for detection of oligoclonal IgG bands in CSF.

Parallel samples of cerebrospinal fluid (CSF) from 120 patients clinically suspected of having multiple sclerosis were electrophoresed using agarose or 7% polyacrylamide. 57 samples showed oligoclonal IgG patterns in polyacrylamide but only 34 showed bands after concentration and electrophoresis in agarose. The concentrations of IgG and albumin were also measured in each sample and IgG/albumin ratios calculated. The sensitivities of the three methods for the detection of intrathecally synthesised IgG were compared. Electrophoresis in 7% polyacrylamide gave the highest proportion of significant results. In an attempt to increase the sensitivity of the agarose method, silver staining was performed on unconcentrated samples run in agarose. This did not alter the pattern of electrophoresis in samples containing oligoclonal IgG, but the sensitivity of the technique was lower than that of polyacrylamide.

Electrophoresis↗
PubMed1987

Autoimmunity to insulin receptor and hypoglycaemia in patient with Hodgkin's disease.

A 76-year-old man with fasting hypoglycaemia had impaired in-vitro binding of insulin to erythrocyte receptors. The immunoglobulin fraction of his plasma inhibited binding of insulin to normal donor erythrocytes in vitro. Autoantibodies may have stimulated the insulin receptor and produced hypoglycaemia. Hodgkin's disease developed and may have induced the autoimmunity. The hypoglycaemia did not respond to plasmapheresis or azathioprine alone, but it remitted after the addition of prednisolone, and the erythrocyte receptor binding of insulin became normal.

Aged↗
PubMed1987

Anti-granulocyte opsonic activity in sera from patients with systemic lupus erythematosus.

Neutropenia is common in patients with systemic lupus erythematosus (SLE) but mechanisms of cell depletion remain obscure. To investigate the possible autoimmune aetiology of neutropenia in SLE, sera from 31 patients with this disorder were tested for anti-granulocyte activity. Granulocyte-binding immunoglobulins were detected by indirect immunofluorescence, and the ability of patient sera to opsonize granulocytes was determined by measuring the chemiluminescent response of human monocytes to granulocytes sensitized by test sera. Sera from 22 of the 31 patients bound IgG to granulocyte cell membranes and/or to nuclei, but only membrane-binding antibodies opsonized the cells for recognition by monocytes. There was no correlation between neutrophil count and the level of granulocyte-binding IgG as measured by indirect immunofluorescence. In contrast, opsonic activity and neutrophil count were inversely correlated (r = 0.5; P less than 0.05). However, opsonic activity was present in sera from most non-neutropenic patients. In patients with SLE, impaired reticuloendothelial system function may allow sensitized granulocytes to remain in the circulation.

Cell Membrane↗
PubMed1987

Indications of vascular endothelial cell dysfunction in systemic lupus erythematosus.

Fibrinolytic and other factors have been measured in 73 patients with systemic lupus erythematosus or related conditions to determine whether clinical thrombosis, a common feature of these disorders, is associated with defective fibrinolysis. Twenty five of 72 (35%) patients, compared with two of 22 (9%) controls, showed a low level of plasminogen activator activity in response to venous occlusion, suggesting decreased fibrinolytic potential. In addition, mean plasma levels of von Willebrand factor antigen and fibronectin were markedly raised in the patients (mean (SD) 384.5 (277)% and 727 (436) mg/l respectively) compared with healthy controls (100 (50)% and 306 (65) mg/l). These data suggest a degree of endothelial cell dysfunction. No clear correlation was found between a history of thrombosis and any plasma factor measured, except for prolongation of clotting tests suggestive of the 'lupus anticoagulant'.

Adult↗
PubMed1987

Variation of erythroid and myeloid precursors in the marrow and peripheral blood of volunteer subjects infected with human parvovirus (B19).

Infection of normal individuals with human parvovirus (B19) results in a mild disease (erythema infectiosum) but gives rise to aplastic crises in patients with chronic hemolytic anemias. The effects of this disease on hemopoiesis were investigated following intranasal inoculation of the virus into three volunteers. A typical disease ensued with a viremia peaking at 9 d. Marrow morphology 6 d after inoculation appeared normal but at 10 d there was a severe loss of erythroid precursors followed by a 1-2-g drop in hemoglobin, and an increase in serum immunoreactive erythropoietin. Erythroid burst-forming units (BFU-E) from the peripheral blood were considerably reduced, starting at the time of viremia and persisting for 4-8 d depending on the individual. Granulocyte-macrophage colony-forming units (CFU-GM) were also affected but the loss started 2 d later. Both CFU-GM and BFU-E showed a sharp overshoot at recovery. In the marrow, BFU-E and CFU-E were reduced at 6 and 10 d in the individual having the longest period of peripheral progenitor loss. In contrast, there was an increase in BFU-E and CFU-E in the subject with least change in peripheral progenitors. In the third subject, with an intermediate picture, there was a loss at 6 d but an increase at 10 d of erythroid progenitors. It is suggested that the architecture of the marrow might partially isolate progenitors from high titers of virus in the serum and individual variation in this respect might give the results observed.

Adult↗
PubMed1987

Intrathecal immunoglobulin synthesis in cerebral malaria.

Local synthesis of immunoglobulin within the central nervous system has been evaluated in 37 patients with acute cerebral malaria; seven patients were also studied in the convalescent phase. There was evidence in the cerebrospinal fluid (CSF) of 21 patients that intrathecal IgG synthesis occurs in the acute phase. There were raised IgG: albumin ratios in 43% of acute patients. Oligoclonal IgG bands or cathodal IgG was seen in the CSF of 43% of patients tested by polyacrylamide electrophoresis. Only eight out of 37 acute patients (22%) had no evidence of intrathecal IgG synthesis by either method. The serial studies showed that most patients had IgG-CSF abnormalities when tested in convalescence. These studies suggest that an immune stimulus (perhaps malarial antigens or mitogens) may be present in the brain in acute cerebral malaria.

Acute Disease↗
PubMed1987

Combined familial C7 and C4B deficiency in an adult with meningococcal disease.

A case of meningococcal septicaemia is reported in an adult with a deficiency of the seventh component of complement combined with a deficiency of the B locus product of C4. A family study demonstrated that the two deficiencies were not linked. This is the first time that the individual alleles of C4 were determined in a patient with a deficiency of one component of the terminal pathway. It is possible that the heterogeneous clinical picture of a terminal pathway deficiency may, in part, be explained by the co-existence of other subtle complement defects.

Adult↗
PubMed1986

Function of the blood-cerebrospinal fluid barrier in human cerebral malaria: rejection of the permeability hypothesis.

We tested the hypothesis that cerebral malaria is caused by blood-brain barrier inflammation and cerebral edema. In a group of 157 Thai patients with strictly defined cerebral malaria, cerebrospinal fluid (CSF) opening pressures were normal in 79% and were lower in fatal cases than in survivors (means +/- 1 SD, 144 +/- 58 and 167 +/- 51 mm CSF, respectively, P = 0.051). CSF: serum albumin ratios (X 10(3)) in 39 of them were significantly higher than in 61 British controls (medians 8.5 and 5.5, respectively, P = 0.04), but were no higher in 7 fatal cases. In a group of 12 patients this ratio was not significantly higher during coma than after full recovery (means +/- 1 SD, 9.0 +/- 6.2 and 6.7 +/- 4.2, respectively, P greater than 0.1). CSF alpha 2-macroglobulin concentrations were always normal. CSF : serum 77Br- ratios were elevated in 11/19 comatose cases but fell to normal 4 to 9 days later in 11/11 cases. Dexamethasone treatment had no significant effect on bromide partition. The percentage of an intravenously administered dose of 125I-human serum albumin detectable per ml of CSF 6 hr after intravenous injection was 2.4 +/- 1.3 X 10(-5) in 14 comatose patients and 4.4 +/- 4.0 X 10(-5) in 9 of them during convalescence (P greater than 0.1). These results demonstrate that the blood-CSF barrier is essentially intact in patients with cerebral malaria and give no support to the idea that cerebral edema is the cause of coma.

Blood-Brain Barrier↗
PubMed1984

Immunoglobulin and other proteins in the cerebrospinal fluid of patients with Alzheimer's disease.

Immunoglobulin has been measured and studied electrophoretically in cerebrospinal fluid (CSF) from 14 patients with Alzheimer's disease and 25 undemented controls. Presence or absence of the diagnosis of Alzheimer's disease was confirmed histologically, as these were postmortem specimens. There was no increased incidence of oligoclonal IgG bands in either group, and no significant differences in the levels of IgG and albumin. Non-immunoglobulin bands were found in the gamma region in some samples from Alzheimer's disease patients and controls; such bands are not found in the CSF from younger patients. There was a significantly increased incidence of double transferrin and double tau protein bands in the Alzheimer's group, suggesting that further studies of genetic markers might be worthwhile.

Aged↗
PubMed1979

A study of the aetiology of gastritis following gastric surgery. I. Immunofluorescent studies of the gastric mucosa.

The gastritis which follows surgical trauma is probably not of autoimmune origin. Although identical with the gastritis of pernicious anaemia (PA) upon routine histological examination, immunofluorescent examination of post-operative gastritis differs in that IgA-containing plasma cells alone are found, in contrast to the predominantly IgG-containing plasma cells in PA.

Adult↗
PubMed1977

Combined T and B lymphocyte marker test in lymphoproliferative disorders.

The combined T and B lymphocyte marker test of Mendes et al (1974) has been developed to provide an easy, reproducible test for clinical practice. It has been used to study subpopulations of peripheral lymphocytes in patients with lymphoid malignancies. Significant increases in the numbers of lymphocytes which bind both sheep erythrocytes (E) and the fixed, third component of complement (C3) have been found using this test, in the peripheral blood of all untreated lymphosarcoma (L/SA) patients and T cell acute lymphoblastic leukaemia (ALL) patients. Such increases were not found in blood from patients with chronic lymphatic leukaemia (CLL), other non-lymphoid malignancies, null-cell ALL or normal individuals. These mixed E and C3 receptor bearing cells may be Fc receptor positive and represent a separate subpopulation of lymphocytes.

B-Lymphocytes↗