Search PubMed⌕ Search

Biomedical subjects

A J Matas

Publications and source records attributed to A J Matas.

At least 379 records · Page 21Linked to original sources
PubMed1976

Hepatocellular transplantation for metabolic deficiencies: decrease of plasms bilirubin in Gunn rats.

A sustained decrease of plasma bilirubin concentrations occurred in homozygous recessive Gunn rats lacking the enzyme uridine diphosphate glucuronyltransferase following infusion into the portal vein of hepatocytes from heterozygous nonjaundiced Gunn rats possessing the enzyme. Transplantation of cells capable of continuous enzyme production could be an effective mode of therapy for congenital enzyme deficiency diseases.

Animals↗
PubMed1976

Post-transplant malignant lymphoma. Distinctive morphologic features related to its pathogenesis.

Malignant lymphoma developed in two patients after renal transplantation. In both, the central nervous system was involved. Histologic study of the tumors showed that they were composed of a monomorphous proliferation of cells characterized by a large vesicular nucleus, prominent basophilic nucleolus and strongly pyroninophilic cytoplasm. The tumors thus would be classified as "diffuse large lymphoid lymphomas with pyroninophilia" or "immunoblastic sarcomas" as described in the literature. Tumor cells resembled cells observed in the paracortex of antigenically stimulated lymph nodes, cells from malignant lymphomas in mice that were antigenically stimulated and from malignant lymphomas in patients with immunodeficiency diseases or autoimmune disorders. The distinctive morphologic features of the tumors in the transplant recipients described provide further evidence that long-term antigenic stimulation may be important in their pathogenesis.

Brain↗
PubMed1976

Seven years' experience with antilymphoblast globulin for renal transplantation from cadaver donors.

Antibody of the IgGab type can be isolated from horses immunized with cultured human lymphoblasts plus complete Freund's adjuvant. The essential steps for the production of a safe, potent anti-human lymphoblast globulin (ALG) are: A) the use of early bleedings after immunization to reduce the titer of antibodies which react with red blood cells and platelets; B) careful absorption with human red blood cell stroma and platelets; C) stabilization with non-crystalline silica dioxide; D) chromatography through QAE sephadex to remove pyrogens, microaggregates and possible inhibitors of ALG activity; E) careful safety testing in animals for toxicity and pyrogenicity; and F) testing in vitro for sterility. Such a purified horse ALG (IgGab) can be administered safely intravenously to patients to supplement a standardized immunosuppressive regimen incorporating azathioprine and prednisone. Under these circumstances, allergic reactions are very rare, antibodies to horse IgG do not develop, skin tests to horse IgG remain negative, and immune elimination of circulating horse IgG from the human circulation cannot be demonstrated. The overall results of ALG patient survival and transplant function after 184 consecutive first cadaver transplants at the University of Minnesota demonstrate a statistically significant improvement in both parameters accompanying increases in ALG dose while rigidly utilizing standardized doses of azathioprine and prednisone. There is a significant reduction in the number of grafts lost to rejection; significant reduction in the number of rejection episodes; significant delay in the onset of rejection episodes; but there is no increase in septic loss of patients or kidneys. These efforts could be seen in the gross data or when subgroups controlling for patient age, tissue typing were analyzed. Excluding patients at high risk did not alter the results. The beneficial effects of ALG were particularly striking in good matches. In the highest doses, ALG may be dangerous for older patients with poor matches who develop an increased incidence of septic loss of kidney and/or life. Thus, ALG appears to be a useful adjunct in the early management of cadaver transplants by reducing the incidence and frequency of rejection episodes. The dose should probably be reduced in the older patients who receive kidneys from badly mismatched donors. One cannot conclude from this study that ALG manufactured in other centers by this or other techniques, will accomplish the same results since the multiplicity of factors involved in the success and failure of transplants must be controlled so that the influence of intravening variables in the assessment of ALG effectiveness can be assessed.

Age Factors↗
PubMed1976

Immunopathological studies of the ruptured human renal allograft.

The immunopathology of five cases of spontaneous allograft rupture has been studied. All kidneys were edematous on exploration and routine histological sections showed interstitial edema and mononuclear cell infiltration characteristic of acute rejection. Immunofluorescence revealed, at most, scattered vascular deposition of IgM and mild mesangial C3 deposition. These findings are compared with findings in normal kidneys and kidneys which had been hyperacutely rejected. The normal kidney showed focal afferent arteriolar and proximal mesangial stalk deposition of C3 without IgM. The kidneys of patients with hyperacute rejection showed brilliant staining for fibrin and IgM in all arterial and arteriolar walls with lesser amounts of C3 and IgG; IgM and C3 were prominent in the glomerulus. These findings suggest that mechanisms other than circulating preformed antibodies are responsible for the pathogenesis of spontaneous allograft rupture.

Fluorescent Antibody Technique↗
PubMed1976

Uremic pericardial effusion. Treatment by catheter drainage and local nonabsorbable steroid administration.

Pericardial drainage via percutaneous catheter placement and local nonabsorbable steroid instillation was employed as definitive therapy for uremic patients who had intractable pericardial effusions. Twelve patients are reported. Prior daily dialysis, and in one case systemic steroids, were not curative. 11 of 12 cases suffered severe tamponade requiring pericardiocentesis. One patient had an organized pericardial effusion, making pericardiocentesis impossible. He required pericardiectomy with prolonged hospitalization (2 weeks) due to postoperative complications. There were no complications in the 11 patients where catheter drainage and local steroid instillation were employed. No patient had recurrence of his pericardial effusion (followed from 2 weeks to 32 months). Instillation of a relatively nonabsorbable steroid through an indwelling pericardial catheter provides immediate and lasting relief without either the inconvenience or postoperative complications and prolonged hospitalization associated with the surgical procedure of pericardial fenestration. This report offers initial evidence that the percutaneous approach may be a safe and effective alternative to pericardial fenestration in most uremic patients with pericardial effusion.

Cardiac Catheterization↗
PubMed1976

Infant human pancreas. A potential source of islet tissue for transplantation.

Twelve pancreases from human infants one year old or less were analyzed for tissue insulin and amylase content before and after dispersal of pancreatic fragments by mincing and collagenase digestion. Tissue insulin and amylase content provide an index of pancreatic islet mass and exocrine digestive enzyme content, respectively. The results were compared with similar anaylses performed on juvenile and adult human pancreases before and after islet isolation and on intact and dispersed neonatal rat and adult rat pancreas. Infant human pancreas has an average tissue insulin concentration of 1,128 mug./gm. of tissue and a total insulin content of 1,718 mug/pancreas, as against values of 140 mug./gm. of tissue and 7,209 mug./pancreas for adult human pancreas. Average tissue amylase concentration is 0.24 mg./gm. of tissue in infant human pancreas and 3.0 mg./gm. of tissue in adult human pancreas. The insulin/amylase ratio in infant pancreas is 4,800, as against 46 in the adult pancreas. Neonatal rat pancreas, which can be dissociated and transplanted without separation of islet and exocrine components, has a similarly high tissue insulin and low tissue amylase content when compared with adult rat pancreases. Infant human pancreas has a total islet mass 24 per cent that of an adult human pancreas, and neonatal rat pancreas has a total islet mass 11 per cent of that of an adult rat pancreas. One neonatal rat pancreas prepared by minimal collagenase digestion can cure diabetes when transplanted via the portal vein to a rat. Following dispersal of infant human pancreas by collagenase digestion, the islet content and the insulin/amylase ratio of the recovered tissue equals or exceeds that which usually can be isolated from adult cadaver pancreases. Infant human pancreas is a rich source of islet tissue that is relatively uncontaminated by exocrine digestive enzymes. After dispersal, infant human pancreas may be ideal for transplantation to selected diabetic patients.

Adolescent↗
PubMed1976

Hyperglycemic pseudorejection in the diabetic transplant patient.

Serum creatinine elevation in a stable transplant recipient most often suggests rejection of the transplant and requires further evaluation and management. In our series of juvenile diabetic patients who have received kidney transplants, we frequently have observed creatinine elevations in association with hyperglycemia. Correction of the hyperglycemia resulted in return of serum creatinine to normal levels and no rejection therapy was required. To better define this syndrome, 2,734 paired measurements of blood glucose and serum creatinine were obtained in 52 stable post-transplant diabetic patients. A mean increase in blood glucose of 100 mg. per 100 ml. was found to increase serum creatinine by 0.5 mg. per 100 ml. in these patients (r=0.93; p less than or equal to 0.001). Evidence strongly suggests that the pathogenesis of this phenomenon is not a result of a laboratory artifact due to the technique used to determine serum creatinine. The pathogenesis may be due to the increased serum osmolarity and resulting intracellular dehydration associated with hyperglycemia. Recognition of this syndrome is important to all centers participating in the care and management of the diabetic transplant recipient.

Acute Kidney Injury↗
PubMed1976

Short-term culture of adult pancreatic fragments for purification and transplantation of islets of Langerhans.

Minced adult human, rat, and dog pancreatic fragments were cultured under various conditions in an attempt to selectively purify pancreatic islet tissue from exocrine digestive enzymes. Islet purification was assessed by measuring tissue insulin and amylase concentrations, proportional to islet beta cell mass and exocrine enzyme content, respectively. Tissue amylase content decreased rapidly over a 24 hour culture period under all conditions. By addition of pilocarpine, cobalt chloride, and aprotinin to the culture medium, pancreatic tissue insulin levels stabilized. Under these conditions the tissue insulin: amylase ratio increased rapidly and a high ratio was maintained, indicating that islet tissue decontaminated of exocrine digestive enzymes was preserved in short-term culture. Fifteen dogs rendered diabetic with streptozotocin immediately following a partial pancreatectomy received an autotransplant of pancreatic tissue fragments maintained in culture for 24 hours. Seven dogs were rendered normoglycemic. Six of these dogs have survived for longer than 30 days. Only one of 14 control pancreatectomized dogs injected with streptozotocin and not transplanted survived and was normoglycemic. Viable islet tissue free of exocrine enzymes can be obtained by short-term culture of pancreatic fragments, and separation of islet and exocrine components of adult pancreas is not essential for successful islet transplantation.

Amylases↗