Search PubMed⌕ Search

Biomedical subjects

R J Pickering

Publications and source records attributed to R J Pickering.

At least 37 records · Page 2Linked to original sources
PubMed1978

Heterogeneity of the clinical syndrome in patients with systemic lupus erythematosus and genetic deficiency of the second complement component.

Two patients with systemic lupus erythematosus associated with homozygous deficiency of the second complement component (SLE-C2D) illustrate the different clinical disease patterns found in patients with this illness. Despite the differences in extent and severity of clinical manifestations and serological findings, the renal disease was similar and kidney function was well preserved in both patients. Renal microscopic changes were focal and segmental, deposits of immuno-globulins and complement components were present by immunofluorescent staining, and dense deposits were seen by electron microscopy. Tubulo-reticular inclusion bodies were found in glomerular endothelial cells and lymphocytes of both patients, but not in the lymphocytes of a clinically healthy C2D sibling. The findings in these two patients stress the importance of careful evaluation to determine the presence of systemic disease in patients with SLE-C2D and suggest that an intact classic complement pathway is important in the development of severe lupus, nephritis, but is not needed in the pathogenesis of lupus skin lesions.

Adult↗
PubMed1976

Disseminated intravascular coagulation induced by Liquoid in the rat. II. Effect of heparin on hematologic and complement abnormalities and renal lesions studied by light, fluorescence, and electron microscopy.

A single intravenous injection (12.5 mg.) of Liquoid (polyanethol sulfonate) was given to anticoagulated (heparinized) rats. Fibrinogen concentrations, platelet counts, total serum complement (CH50),C3 protein, and terminal components (C3 to C9) were measured. Histopathology was assessed by light, fluorescence, and electron microscopy. Heparin given before Liquoid remarkably diminished the seferity of the histologic lesions, with good correlation among light, fluorescence, and electron microscopy. Levels of clotting factors, CH50, C3 and C3 to C9, however, were not statistically different in the heparinized rats injected with Liquoid from those of animals receiving Liquoid alone. Actually C3 protein concentration was lower in the anticoagulated (Liquoid-heparin) rats. It is postulated that under the present experimental conditions, heparin did not antagonize the procoagulant and precipitating or complement-activating Liquoid effects. The attenuated histopathology observed was perhaps the result of either local or systemic, as yet undefined, heparin effects other than anticoagulation.

Animals↗
PubMed1976

C4 synthesis in C4-deficient guinea pig radiation chimeras: restoration of the classic complement pathway.

Bone marrow transplants from normal Albany strain guinea pigs established a functional classical pathway of complement (C) in C4-deficient (C4D) guinea pigs. Seventeen days after transplant the Albany leads to C4D chimeras had detectable C4 and total hemolytic C activities. Maximum C4 levels (2 to 8% of normal were reachered by day 73 and restored total C to 40% of normal. Classical pathway function persisted for about 150 days and, thereafter, declined to undetectable levels by day 385. In contrast, Albany guinea pigs transplanted with C4D marrow maintained normal C4 levels throughout the experiment, suggesting that the C4-producing cells are radioresistant and long-lived. Unlike unmanipulated C4D animals, Albany leads to C4D chimeras were unable to produce antibodies to guinea pig C4 when immunized with normal guinea pig serum. These experiments suggest that bone marrow cell progeny produce C4 in vivo.

Animals↗
PubMed1975

Endothelial injury induced by bacterial endotoxin: effect of complement depletion.

The role of complement activation in the pathogenesis of endothelial injury caused by bacterial endotoxin was investigated in the rat. DNA synthesis in aortic endothelium was compared 48 hours after an intravenous injection of endotoxin (50 - 500 mug) in normal rats and in rats depleted of haemolytic complement by purified cobra venom factor. At the time of endotoxin administration the rats treated with cobra venom factor had less than 3% of the normal haemolytic complement level, their fibrinogen level was increased and clot retraction was impaired. Endotoxin stimulated endothelial DNA synthesis to the same degree in normal and in complement-depleted rats. Cobra venom factor alone did not stimulate endothelial DNA synthesis. The complement-depleted rats given 500 mug endotoxin were less thrombocytopenic than normal rats at the time of sacrifice, but the difference was not statistically significant. We conclude that the injurious effect endotoxin has on endothelium is not mediated by activation of late components of complement.

Animals↗
PubMed1975

Combined immunodeficiency disease associated with adenosine deaminase deficiency. Report on a workshop held in Albany, New York, October 1, 1973.

Fifty-five children with CID and known ADA status were studies at a workshop held in Albany, New York. Erythrocyte ADA determinations were performed in 22 of the 55 patients, 13 of whom were ADA negative. The ADA defect appears to be transmitted as an autosomal recessive trait. Some patients with CID and ADA deficiency have characteristic radiologic abnormalities of the skeleton, which are not found in other illnesses. The thymus glands of all patients with CID and ADA deficiency who could be examined have evidence of thymic involution manifested by presence of Hassall's corpuscles and differentiated germinal epithelium; this is in contrast to "classic" thymus findings in CID with normal ADA. Adenosine deaminase probably plays an important, although as yet undefined, role in lymphocyte development and/or function. The deficiency of ADA in CID is the first enzyme defect observed in a deficiency disease of specific immunity.

Adenosine↗
PubMed1975

Disseminated intravascular coagulation induced by liquoid in the rat. I. Correlation of hematologic and complement abnormalities with renal lesions studied by light, fluorescence, and electron microscopy.

Under the proper experimental conditions, disseminated intravascular coagulation,"an intermediary mechanism of disease," results in the classic endotoxin-induced generalized Shwartzman reaction. Other substances, such as liquoid, a highly negatively charged anticoagulant, trigger a generalized Shwartzman reaction-like phenomenon in rabbits. We studied the effects of a single high intravenous dose of liquoid (12.5 mg.) upon the rat's coagulation and complement systems and their correlation with the kidney morphology by light, fluorescence, and electron microscopy. Thrombin time was prolonged; fibrinogen, plasminogen, and factors VIII and XII concentrations were markedly decreased, whereas fibrin degradation products were increased in the experimental animals when compared with the saline-injected controls (p greater than 0.001). Total hemolytic complement, hemolytic activity of terminal components (C3 to C9), and C3 protein concentration were significantly reduced (p greater than 0.001). The liquoid-injected rats developed cortical necrosis and manifested oliguria and anuria, with elevated blood urea nitrogen levels, when survival was longer than 3 hours. Histologically, thrombi of fibrin-like material filled the glomerular capillaries. Deposits of fibrin, and also of immunoglobulin G and C3, were readily identifiable by specific immunofluorescence, Linear or granular fluorescent deposits (or both) along the glomerular basement membranes and in the mesangium were observed. Electron microscopy demonstrated necrosis of glomeruli and abundant thrombi of fluffy, compact granular, or fibrillar electron-dense material. No typical fibrin periodicity was detected. These experiments support the concept of activation of the coagulation and the complement systems. We postulate that liquoid produced not only a consumptive coagulopathy in the rat but also a direct or perhaps anindirect activation of complement. Whether this latter has occurred through the classic or an alternate pathway remains to be elucidated.

Animals↗
PubMed1975

Adenosine deaminase deficiency in combined immunologic deficiency disease.

Deficiency of red cell and lymphocyte adenosine deaminase (ADA) was found in children suffering from congenital combined immunologic deficiency. The parents had ADA levels intermediate between patients and controls. Complete lack of ADA activity was not found in normal subjects or in patients with a variety of other immunologic deficiency diseases.

Adenosine Deaminase↗
PubMed1975

Combined immunodeficiency disease: an inborn error of purine metabolism.

The recently discovered association of adenosine deaminase (ADA) deficiency and combined immune deficiency (CID) has emphasized the critical role of purine salvage in the function of lymphoid tissue. Known enzymatic properties of ADA are presented. In addition, known phenotypic data and possible genetic mechanisms for the occurrence of ADA deficiency in CID are discussed. A hypothesis based on considerations of known metabolic pathways in human erythrocytes is proposed to account for the selectivity of ADA deficiency for lymphoid tissue. Finally, some inhibitors of ADA are discussed as well as some immunosuppressive agents.

Adenine↗