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Biomedical subjects

R E Urizar

Publications and source records attributed to R E Urizar.

36 records · Page 2Linked to original sources
PubMed1979

Abnormalities of the complement system in Reye syndrome.

Sixteen patients with Reye syndrome had diminished concentration of serum complement proteins and/or hemolytic activity in the earliest blood sample. All 12 studied with hemolytic methods had significantly reduced C1 activity; total hemolytic complement activity was reduced in only three. Low Cl activity was accompanied by equivalent reduction of Cls in 11 of 12 patients; Clq was less than normal in only two of 12. Decreased levels of at least one other classical pathway complement hemolytic activity or protein concentration were found in 13 patients, whereas factor B or the alternate complement pathway was normal or elevated in the ten patients studied. The consistent reduction of Cls protein concentration in Reye syndrome suggests that early metabolic abnormalities regularly affect the production or catabolism of this protein. Although normal serum Clq concentration in the majority of these patients does not support an immune pathogenesis, decreased Clq, C4, and C2 in three patients does suggest that immune mechanisms may be responsible for the serum complement abnormalities in this latter group of patients.

Adolescent↗
PubMed1978

Henoch-Schönlein anaphylactoid purpura nephropathy: electron microscopic lesions mimicking acute poststreptococcal nephritis.

The clinical, laboratory, and histologic features of a patient with Henoch-Schönlein syndrome are presented. The skin biopsy examination showed "leucocytoclastic vasculitis." Kidney tissue demonstrated deposits of IgG, C3, and fibrinogenfibrin by fluorescence microscopy in the mesangium and the peripheral glomerular basement membrane in a granular-nodular pattern. These correlated well with areas of mesangial hyperplasia and polymorphonuclear leucocyte infiltration seen by light and electron microscopy. Several well delineated, variably sized, subepithelial electron dense deposits flanked by polymorphonuclear leucotytes adherent to the glomerular basement membrane were seen in two of the four glomeruli examined by electron microscopy. The significance of these findings is discussed. A detailed ultrastructural evaluation of patients with Henoch-Schönlein nephropathy may yield information about the frequency of subepithelial deposits and perhaps may help to clarify the pathogenesis of this syndrome.

Diagnosis, Differential↗
PubMed1978

Dactinomycin treatment of murine lupus erythematosus. I. Renal disease and longevity.

Three groups of female (NZB X NZW)F1 hybrid mice were treated with an intermittent regimen of dactinomycin (actinomycin D), 3.5 microgram. daily. Median survival was doubled in two of the groups and increased by more than 75 per cent in the third. Most of the treated animals never had significant proteinuria. When kidneys from 14 treated mice, which died between the ages of 11 and 20 months, were examined by light and fluorescence microscopy, most showed the lesions of normal aged CBA and C57BL/6 mice, some expansion of the mesangial matrix and increased cellularity, consistent with deposition of immunoglobulins and complement components in the mesangium, generally sparing the capillary loops. Four of the 14 animals, three of them long-lived, had advanced renal glomerular disease. These data indicate that dactinomycin, by whatever therapeutic mechanism, permits very extended survival of B/W female mice, the large majority of them without significant renal disease.

Animals↗
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↗
PubMed1977

Ultrastructural lesions of muscle and immunofluorescent deposits in vessels in Reye's syndrome: a preliminary report of serial muscle biopsies.

Thirteen sequential percutaneous skeletal muscle biopsy specimens from 4 patients with Reye's syndrome were studied ultrastructurally and by direct immunofluorescence. Prominent generalized intermyofibrillar edema, mitochondrial disruption, and swelling of vascular endothelium were demonstrated in 2 patients. In all 4 patients there were granular deposits of immunoglobulins G and M in intramuscular vessels, presumably representing antigen-antibody complexes. We postulate that these changes may be pathogenetically important in this syndrome and suggest that muscle biopsy tissue be utilized for further investigation of Reye's syndrome.

Antigen-Antibody Complex↗
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↗
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↗