Biomedical subjects
Publications and source records attributed to R D Barr.
In a study in Nairobi, Kenya, 30 young adults with nephrotic syndrome were investigated in detail and a further 18 were studied less completely. In no case was evidence found to support a possible role for malaria in the aetiology of the syndrome.
The adult nephrotic syndrome as met with in Nairobi is predominantly encountered in young sophisticated African women, most of whom began to use skin-lightening creams containing mercury before the symptomatic onset of their illness. The particular form of mercury involved is well known to cause the nephrotic syndrome in other circumstances-for example, when applied to the skin in the treatment of psoriasis. In these circumstances the pathogenetic mechanism is thought to be of an idiosyncratic type. The use of mercury-containing skin-lightening creams in the patients studied seemed to be particularly associated with a "minimal-change" ("light-negative") renal glomerular lesion, this lesion being present in half of the patients. The prognosis in this group of patients seems remarkably good, with 50% entering remission, 77% of these doing so spontaneously on discontinuing the use of the creams.
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Infusion of commercial preparations of porcine and bovine antihaemophilic globulin into three haemophilic patients produced transient thrombocytopenia. This platelet-aggregating activity has been shown to be present in a wide range of animal plasmas and is related to the fibrinogen fraction. The mechanism of platelet aggregation by animal fibrinogen is discussed and some inhibitors of the reaction are described.
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Human peripheral blood may be an alternative to bone marrow as a source of cells for hemopoietic engraftment. The ability to collect large numbers of circulating granulocyte-macrophage progenitors provides support for this contention. In the present study of cells from normal granulocyte donors, the cell concentrates obtained by cytapheresis were shown to contain even greater numbers of primitive erythroid precursors (153-956 [median 647] per 10(6) mononuclear cells) than would be predicted from the peripheral blood mononuclear cell counts. Moreover, the number of primitive erythroid precursors harvested correlated significantly with the number of granulocyte-macrophage progenitors obtained and with the total lymphocyte collection. These observations further substantiate the validity of transplanting peripheral blood as hemopoietic tissue.
In a group of 23 children with acute leukemia, all but one of whom had entered complete remission, retrospective analysis of hematological profiles demonstrated that administration of consolidation chemotherapy, with a combination of cytosine arabinoside (Ara-C) and 6-thioguanine (TG), was associated with a fall in the erythrocyte concentration in peripheral blood, the rate of which was at least as fast as would have occurred with total marrow ablation and consequent red cell aplasia. In the absence of profound myelosuppression or detectable hemorrhage, drug-induced erythrocytotoxicity was suspected, prompting in vitro studies of erythrocytes from children with acute leukemia and normal adults. At therapeutic concentration, Ara-C and TG, individually and in combination, produced significant stomatocytosis in samples from both groups. Since phenothiazines are stomatocytogenic and are administered as anti-emetics in conjunction with cancer chemotherapy, chlorpromazine was investigated in parallel studies that demonstrated stomatocytosis at therapeutic concentration, but no consistent interaction with the effects of Ara-C and TG in this regard. These observations suggest a possible pathogenetic mechanism for the development of anemia resulting from drug-induced erythrocytotoxicity.
PURPOSE: This report describes the clinical course of three siblings, all of whom had Evans syndrome in childhood. PATIENTS: The coexistence of autoimmune hemolytic anemia and thrombocytopenia, in the absence of a known underlying cause, led to the diagnosis of Evans syndrome in a 4-month-old girl and subsequently in her two brothers when they were 4 and 13 years old. RESULTS: The 4-month-old girl had a life-threatening relapsing course unresponsive to corticosteroids, intravenous gamma-globulin, thymectomy, and cyclophosphamide. She eventually responded to splenectomy. Her two brothers had milder disease that responded to corticosteroids. Cytogenetic analyses revealed the presence of a familial Y;15 translocation in all three children and their father. CONCLUSION: There are few reported cases of familial Evans syndrome, and they are usually associated with an inherited congenital abnormality. We report the unusual finding of three siblings with the disease and no known congenital abnormality.
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The use of central venous lines has come to be widely accepted by children with cancer and their families. However, attendant infection is a cause of considerable morbidity. Coagulase-negative staphylococci, the predominant aerobic species on the skin, are now the commonest cause of catheter-related bacteremia. We introduced a protocol to reduce the colonization of the skin at the catheter insertion site. Antiseptic skin scrubs, with 4% chlorhexidine gluconate, were performed on the neck and anterior chest the night before and again on the morning of the surgical procedure. A single dose of cephalothin (or vancomycin for penicillin-allergic patients) was administered IV immediately before the operation. Compared to the 12 month period prior to initiation of this protocol, the rate of infections (occurring within 30 days of catheter placement) in the 3.5 year period of intervention dropped from 8 to 4.9 per 1,000 catheter days. The proportion of infections that were staphylococcal was reduced from 93 to 63% and the proportion of non-ports removed within 30 days of placement fell from 45 to 0%. Despite these changes, the major contribution to improved infection control appeared to be the use of an increased proportion of ports (a rise from <10 to almost 60%).