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Biomedical subjects

K Stevens

Publications and source records attributed to K Stevens.

At least 91 records · Page 5Linked to original sources
PubMed1983

Platelet-bound IgM in autoimmune thrombocytopenia.

Elevated levels of platelet-bound IgG (PA-IgG) are a feature of autoimmune thrombocytopenia (ATP), but it is well documented that this does not occur in all cases. This has led us to investigate the role of platelet-bound IgM (PA-IgM) in these patients using a quantitative enzyme-linked immunosorbent assay (ELISA). Forty-five determinations of PA-IgM and PA-IgG were done on 24 patients with ATP. Elevated levels of PA-IgM were found in 93.3% of the determinations, while PA-IgG was elevated in only 71.7%. In 64.4% of determinations, both were elevated. Elevated PA-IgM or PA-IgG alone occurred in 28.9% and 6.7% of determinations, respectively. These results show the hitherto unrecognized frequent involvement of PA-IgM in ATP and suggests that a complex interrelationship exists between the two immunoglobulin classes in ATP. Some of the possibilities that might explain this interrelationship are discussed.

Autoimmune Diseases↗
PubMed1981

Haemoglobin Leiden in a South African negro. A case report.

A Black patient in whom an acute febrile illness was followed by a haemolytic crisis is presented. Investigation of the haemolytic anaemia showed the presence of an unstable haemoglobin which was found to be haemoglobin Leiden. Those members of the family who were available for investigation also had the unstable haemoglobin but showed no haemolysis. Radio-isotope studies on the patient confirmed haemolysis but showed that the spleen was not the main site of cell destruction.

Adult↗
PubMed1980

A new method for the simultaneous quantitation of platelet-bound immunoglobuin (IgG) and complement (C3) employing an enzyme-linked immunosorbent assay (ELISA) procedure.

An ELISA technique for the quantitation of platelet-bound IgG and C3 is described. This is an antiglobulin consumption assay using commercial horseradish peroxidase conjugated anti-IgG and anti-C3 antisera. The greater the amount of antiglobulin consumed by the reaction with platelets the less is available to bind to an immune adsorbent in the form of human serum-coated polystyrene balls. This test can be calibrated by adding known quantities of IgG of C3 to the specific enzyme-linked antibody and the unbound fraction of antiserum is quantitated by allowing it to react with a chromogenic substrate for the enzyme and measuring the intensity spectrophotometrically, thus establishing an inverse relationship with the amount of antigen. Platelets from normal donors and those with non-immunological thrombocytopenia gave values of 1.3--15.5 ng IgG/10(6) platelets and 0.22--0.96 ng C3/10(6) platelets which are in accordance with the normal ratio of these proteins in normal serum. Fifteen patients in whom immune destruction of platelets weas suspected had excess platelet-bound IgG ranging from 30 to 450 ng IgG/10(6) platelets. In none of these patients could excess platelet-bound C3 be demonstrated. Compared to the antiglobulin consumption test we have found this test to be superior both technically and in terms of sensitivity and reproducibility.

Blood Platelets↗
PubMed1979

Acute leukemia as a complication of long-term treatment of advanced breast cancer.

Acute nonlymphocytic leukemia occurred in four women after long-term therapy for advanced breast cancer. The patients had inoperable/metastatic breast cancer that had been well-controlled with chemotherapy for many years (7 years and 4 months, 7 years and 1 month, 6 years and 3 months, and 4 years and 7 months, respectively). Two of the patients had also received extensive radiotherapy. The chemotherapeutic agent that all four patients had received in common was cyclophosphamide.

Adult↗
PubMed1978

Histiocytosis and a leukaemoid response. A case report.

A patient with all the clinical signs of Letterer-Siwe disease is reported. The patient was unusual in that he had a severe leukaemoid reaction. To our knowledge, only 2 similar patients with reticulo-endotheliosis, histiocytic skin infiltration and leukaemoid reaction have been reported. It is possible that the disorder may represent a variant of the histiocytic proliferative disorders, characterized by both histiocytic and myeloid hyperplasia, and is thus similar to myelomonocytic leukaemia. However, it differs from the latter condition in that there is proliferation of monocytes and granulocytes in soft tissues rather than in the blood.

Blood Cell Count↗
PubMed1976

Chronic myeloid leukaemia in South African blacks.

A study on 25 South African Black patients with chronic myelogenous leukaemia (CML), who were followed for 3 1/2 years, is reported. The Ph chromosome was found in 19 of 20 patients studied. Males predominated in a ratio of 2,5:1. Several unusual clinical features were encountered: significant lymphadenopathy, congestive cardiac failure and skin lesions. Patients with lymphadenopathy responded to busulphan therapy no differently from patients without lymphadenopathy. Nine patients had congestive cardiac failure, and in 7 of these a cause could not be found. Three untreated patients became pregnant, indicating that CML per se does not cause infertility. The haematological measurements were similar to those of previous reports; however, the marked splenomegaly suggests that South African Black patients present themselves for treatment rather late in the disease. The median survival time of 34 months is similar to that of previous reports of larger series from other parts of the world.

Adult↗