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Biomedical subjects

I Mohammed

Publications and source records attributed to I Mohammed.

At least 55 records · Page 3Linked to original sources
PubMed1979

Palindromic rheumatism. II. Failure to detect circulating immune complexes during acute episodes.

Thirty-eight samples of blood and 2 of synovial fluid were obtained from 19 patients suffering from palindromic rheumatism. In 12 cases samples were obtained from the same patient both during and between acute attacks. The presence of immune complexes was sought by a C1q-binding test. Most patients gave negative results: moderately elevated levels were obtained in a few. Broadly the pattern of results showed that individual patients were either positive or negative irrespective of whether they were in an attack or in remission. C3 and C4 measurements showed no significant abnormalities, confirming previous studies. Patients with elevated C1q-binding tests tended to be seropositive. We speculate that these are patients more likely to develop rheumatoid arthritis.

Acute Disease↗
PubMed1979

Circulating immune complexes in patients with cryptogenic fibrosing alveolitis.

Increased Clq binding levels have been obtained in serum from twenty-one (50%) of forty-two patients with cryptogenic fibrosing alveolitis (CFA) suggesting the presence of circulating immune complexes. There was a low frequency of positive results using a number of other tests for circulating immune complexes. The increased Clq binding levels were observed in six (35%) out of seventeen patients with lone lung involvement and in fifteen (60%) out of twenty-five patients with extrapulmonary connective tissue disorders. There was an especially close correlation between arthritis and elevated Clq binding. A strong correlation between Clq binding levels and levels of circulating rheumatoid factor (RF) and IgG, and enhancement in macrophage radiobioassay tests using RF-containing sera, suggested that RF might be involved in the circulating immune complexes in these patients. DNAase pre-treatment of sera did not influence the findings, and there was no correlation between Clq binding and levels of immunofluorescent ANA, C-reactive protein levels, or platelet counts. A weak correlation between Clq binding and erythrocyte sedimentation rates, and slightly lower binding levels in treated than untreated patients with 'lone' CFA suggested that binding levels may give some indication of disease activity and may in some instances be influenced by treatment.

Adult↗
PubMed1978

A study of the role of immunological factors in the pathogenesis of the anaemia of acute malaria.

Children with acute Plasmodium falciparum malaria and anemia were investigated to see if immunological factors could be implicated in the pathogenesis of their anaemia. Direct Coombs tests using an anti-whole immunoglobulin antiserum were negative in all 12 children tested but two had positive tests with antisera to C3b and C3d. Low plasma levels of C3 and C4 were found but these were not significantly different from values found in a group of children with acute malaria who were not anaemic. Serum levels of immune complexes were normal at the time of their presentation at hospital with anaemia but were elevated one month later. Incubation of group O rhesus-negative red cells in a serum pool obtained from children with acute malaria and anaemia did not cause enhanced haemolysis or reduce their survival time on injection into mice. Splenic uptake of red cells was, however, significantly enhanced. We conclude that the anaemia of acute malaria is due mainly to destruction of red cells by malaria parasites and to enhanced erythrophagocytosis of normal cells.

Acute Disease↗
PubMed1978

Tropical acute rheumatic fever and associated streptococcal infections compared with concurrent acute glomerulonephritis.

Ninety-three patients with acute rheumatic fever and 195 patients with acute glomerulonephritis were observed in Trinidad during an outbreak of scabies with a high incidence of secondary streptococcal infections. Clinical and laboratory manifestations of ARF were the same as those seen in temperate zones, except that antistreptolysin O titers were less markedly increased. The patients with ARF were similar to those with AGN in respect to sex, race, location of residence, and living conditions, but were older and had markedly fewer skin infections. Currently prevalent nephritogenic streptococcal strains never were isolated from patients with ARF even when M55 streptococci appeared and led to an epidemic of AGN.

Acute Disease↗
PubMed1978

Cryoglobulinaemia and circulating immune complexes in tropical splenomegaly syndrome.

Large amounts of cryoglobulins and soluble immune complexes were detected in the sera of thirteen patients with tropical spenomegaly syndrome (TSS). Complexes were detected by three different methods: radiobioassay, a modified rheumatoid factor-binding activity method and a modified Clq-binding assay. Protein precipitable by 4% polyethylene glycol (PEG) was also measured. The cryoglobulins contained IgM, IgG and in some cases, C3. It is likely that in TSS, marked immune complex formation is associated with hypergammaglobulinaemia and that continuous engulfment of these complexes by cells of the reticuloendothelial system (RES) is the cause of the hepatosplenomegaly.

Antigen-Antibody Complex↗
PubMed1977

Immune complexes and abnormal liver function in haemophilia.

Abnormal 125I-Clq-binding activity was found in the sera of 94% of 55 haemophiliacs. Sera from 66% of these patients inhibited macrophage uptake of labelled aggregated human IgG in a competitive radiobioassay. These results suggest that large molecular weight immune complexes are present in these sera. Analysis of the precipitates obtained directly from the sera by addition of 4% polyethylene glycol showed either a mixture of IgG and IgM or IgM alone. There was poor correlation between the radiobioassay results and the Clq-binding activities in the whole group of 55 patients, suggesting a heterogeneous population of complexes. Nevertheless, a significant correlation was found between Clq-binding activities and the radiobioassay results in seven patients with antibodies to factor VIII, suggesting a homogeneous population of complexes. There was poor correlation between the level of immune complexes and the amount of replacement therapy the patient had received in the previous six months. Abnormal liver function tests were found in 55% of the patients studied but there was poor correlation between these abnormal levels and the Clq binding activities and radiobioassay results. Only two patients had clinical evidence of liver disease.

Adult↗
PubMed1976

Multiple immune complexes and hypocomplementaemia in dermatitis herpetiformis and coeliac disease.

Circulating immune complexes have been detected in 100% of 59 patients with dermatitis herpetiformis (D.H.), and in 100% of 27 patients with coeliac disease (C.D.). Three methods for detecting immune complexes were employed: radiobioassay, which gave an incidence of 77% in D.H. and 81% in C.D.; C1q binding activity, with which the incidence was 83% and 96%, respectively; and precipitation with 4% polyethylene glycol (69% positivity in D.H., 100% in C.D.). The immune complexes in D.H. and C.D. were compared with those in sera from 23 patients with systemic lupus erythematosus (S.L.E.). Multiple complexes of differing properties were found in D.H. and C.D. but not in S.L.E. The varying nature of the complexes in D.H. and C.D. may account for the damage to different tissues (skin, small intestine, reticuloendothelial system). Low third component of complement was found in 49% and low C4 in 20% of D.H. patients. C3 hypocomplementaemia was found in 26% of patients with C.D.

Adult↗
PubMed1975

Effect of penicillamine therapy on circulating immune complexes in rheumatoid arthritis.

The sera of 40 patients with severe progressive rheumatoid arthritis were examined for the presence of soluble immune complexes before penicillamine therapy was started, and again after treatment for a mean period of 14-4 months. The methods used were radiobioassay (macrophage uptake), C1q-binding capacity, and precipitation by 4% polyethylene glycol. Before treatment the sera of 37 patients showed significantly enhanced uptake of 125I-labelled aggregated human IgG by guinea pig macrophages. Treatment produced significant falls in mean erythrocyte sedimentation rate, differential agglutination titre, and serum IgG and IgM levels, and enhancing complexes (EC) decreased or disappeared in 20 patients. In 9 patients EC changed to inhibiting complexes, and in 8 EC levels were unchanged. In 6 of 8 patients with cutaneous vasculitis initially, both lesions and EC disappeared. The total protein and the IgG and IgM precipitated from patients' sera by 4% polyethylene glycol fell significantly on treatment. Antinuclear antibody titres were unchanged by penicillamine, and 3 patients acquired these antibodies during treatment. These findings suggest that penicillamine treatment in rheumatoid arthritis reduces the level of circulating soluble immune complexes in which IgM rheumatoid factor is a component.

Adult↗