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Biomedical subjects

A Kanfer

Publications and source records attributed to A Kanfer.

At least 19 recordsLinked to original sources
PubMed1992

[Reduction of TNF-alpha release and clinical effects of the first injection of OKT3].

In order to prevent the adverse effects of a first OKT3 injection in renal transplant recipients, we administered polyclonal antilymphocyte globulins (ATG Fresenius, 4 mg/kg/j) for 3 days before OKT3 injection. Compared with a historical group of 5 patients who did not receive ATG pretreatment before OKT3 injection, the patients who were pretreated by ATG had a significantly lower absolute number of circulating lymphocytes before the first OKT3 injection (363 +/- 107 vs 1,230 +/- 80/mm3, P < 0.001), a lower raise in plasma TNF-alpha level 2 hours after OKT3 injection (178 +/- 42 vs 735 +/- 127 pg/ml, P < 0.005) and a significant decrease in frequency and intensity of clinical symptoms, mainly chills, dyspnea, and headaches. However, fever and peak creatinine level were similar in both groups. A 80 percent success rate of crisis treatment was achieved in both groups and there was no increase in infectious complications. In conclusion, pretreatment with ATG induces a lymphocyte depletion, and decreases the amounts of TNF-alpha released as well as the side-effects of a first OKT3 injection.

Antilymphocyte Serum↗
PubMed1992

Quantification and modulation of thrombomodulin activity in isolated rat and human glomeruli.

Thrombomodulin (TM), the endothelial cell surface receptor for thrombin-mediated activation of protein C and of its anticoagulant system, is involved in maintaining vascular nonthrombogenicity, and depressed TM activity may induce intravascular fibrin formation. TM antigen was previously found by immunohistochemical methods in rabbit glomeruli. We therefore attempted to identify the corresponding TM activity in isolated detergent-solubilized rat and human glomeruli. Like purified lung TM, rat glomeruli extracts accelerated the hydrolysis by activated protein C of the chromogenic substrate S-2238 in the presence of 10 nM thrombin, as determined by spectrophotometry. One mg glomerular protein promoted the formation of 681 +/- 115 nmol activated protein C, the equivalent of the amount generated by 845 ng of purified rabbit TM. TM activity correlated with the protein content of the glomerular extracts (r = 0.94). These extracts prolonged rat plasma activated partial thromboplastin time. Incubation of glomeruli with tumor necrosis factor-alpha (TNF) or E. coli lipopolysaccharide depressed their TM-like activity in a dose and time dependent manner. Incubation with TNF suppressed their anticoagulant activity. In human glomeruli, TM activity was also found at a level which corresponded to their TM antigen content, and was determined by ELISA with mouse monoclonal antibody. These results indicate that measurement of glomerular TM activity might help to clarify the mechanisms of intraglomerular fibrin deposition in renal diseases.

Animals↗
PubMed1992

Glomerular coagulation system in renal diseases.

Glomeruli possess a complex hemostasis system with prothrombotic (procoagulant, antifibrinolytic) and antithrombotic (anticoagulant, fibrinolytic) properties that can act locally on platelet adhesion or aggregation, on plasmatic coagulation pathways, and on fibrinolysis. In vitro, inflammatory mediators, such as TNF, favor glomerular thrombogenic properties through enhancement of thromboplastin synthesis and of plasminogen activator inhibitor PAI-1, and through decrease in thrombomodulin activity. In some diseases, intraglomerular fibrin formation appears to be favored by increased glomerular prothrombotic properties, for example: augmented thromboplastin activity in immune glomerulonephritides and in Shwartzman phenomenon, excessive thromboxane A2 synthesis, and decreased fibrinolytic activity in severe renal allograft rejection. In other diseases glomerular hemostasis appears to function homeostatically, for example, in thrombin-induced disseminated intravascular coagulation with enhancement of fibrinolytic activity favoring fibrin dissolution. Novel methods allowing the study of glomerular hemostatic activities in renal biopsy fragments should help to understand the mechanisms of fibrin deposition in human diseases and to treat it on a logical basis.

Acute Kidney Injury↗
PubMed1992

[Role of hemostasis in the formation of crescents in extracapillary glomerulonephritis].

Extracapillary glomerulonephritis are associated with fibrin deposition in the urinary space of the glomerulus. Such deposits were correlated with the severity of the disease and with a poor renal outcome. Fibrin formation involves an activation of the coagulation cascade either through the intrinsic pathway, Hageman factor being activated by the altered glomerular basement membrane, either by the extrinsic pathway, infiltrating monocytes and glomerular cells exhibiting a procoagulant activity i.e. thromboplastin or tissue factor. Treatments with heparin or warfarin were shown to decrease the severity of experimental glomerular diseases. A similar beneficial effect was obtained with a monocyte-depleting serum and more recently with a treatment by a tissue type plasminogen activator. Glomerular cells also produce a fibrinolytic activity which could be too low or uneffective on extracapillary fibrin deposits if they contain high amounts of plasminogen activator inhibitors. Thrombin has procoagulant activity, antifibrinolytic activity and has cellular chemotactic and proliferative effects. It could play a major role in the pathogenesis of crescent formation.

Animals↗
PubMed1992

[Thrombosis and disorders of hemostasis in nephrotic syndrome].

Thromboses and disorders of hemostasis in nephrotic syndrome. Thromboembolic complications are common in nephrotic syndrome (NS). This article reviews the factors of thrombogenesis in NS, including: 1) a hypercoagulable state with platelet hyperaggregability, hyperfibrinogenemia and elevated factor VIII, decrease in plasma levels of coagulation inhibitors antithrombin III and free protein S, reduced fibrinolytic activity; 2) excessive intravascular thrombin formation marked by increased plasma levels of fibrinopeptide A. The intensity of hemostasis disorders coincides with that of NS. Most disorders are related to hypoalbuminemia and proteinuria. In agreement with experimental data, the role of intraglomerular activation of coagulation during active phases of glomerulopathies has to be considered. This could explain the predominance of renal vein thrombosis in several glomerulopathies with NS. Several coagulation disorders in SN have implications for therapy.

Blood Coagulation Disorders↗
PubMed1991

[Treatment of cytomegalovirus infections in renal transplants].

Primary cytomegalovirus (CMV) disease can be prevented in renal transplant recipient with the use of either CMV hyperimmune globulin or acyclovir. When started before transplantation and continued for 12 to 16 weeks, these treatments decrease significantly the incidence of primary CMV disease. However they are not always effective and their effectiveness for the prevention of CMV reinfection or reactivation has not been established. Other prophylactic methods, such as vaccination or interferon alpha are not effective. Ganciclovir has been shown to be effective for the treatment of overt CMV disease, provided it is administered early. Combined treatments with CMV hyperimmune globulins and ganciclovir can be used in the most severe forms of the disease. Foscarnet can also be effective, however its nephrotoxicity limits its use in renal transplant recipients.

Acyclovir↗
PubMed1979

Prognostic importance of vascular lesions in acute renal failure with microangiopathic hemolytic anemia (hemolytic-uremic syndrome): clinicopathologic study in 20 adults.

Renal biopsies obtained from 20 adult patients within 30 days after onset of acute renal failure with microangiopathic hemolytic anemia ("the hemolytic-uremic syndrome") were studied. Lesions were graded independently by two observers without knowledge of the clinical history. All patients who did not have refractory hypertension were treated with heparin. Ten of the patients died, and four developed end-stage renal failure requiring chronic dialysis. Six patients, however, had a relatively good outcome: two recovered completely and four developed mild-to-moderate chronic renal failure not requiring dialysis. The six patients with a good outcome had significantly less severe arterial intimal thickening on biopsy compared with the remaining patients with a poor outcome. The patients with a good outcome and those with a poor outcome did not differ in the severity of glomerular lesions. The clinical features did not allow a prediction of late outcome. These results suggest that early renal biopsies may be helpful in predicting prognosis in the "hemolytic-uremic syndrome." This clinical syndrome may occur either in apparently healthy people, or may complicate the course of a chronic essential hypertension.

Acute Kidney Injury↗
PubMed1978

Immunologically mediated drug-induced acute renal failure.

(1) AIN is the most frequent pattern of drug-induced immunologically mediated renal injury. A number of drugs may be responsible for AIN, namely methicillin and other penicillin derivatives, rifampicin, phenindione and sulfonamides. Particular clinical and pathological features often suggest an immune pathogenetic mechanism. IgG anti-TBM and IgE antibodies have been found in only a few cases and it is likely that antibody-mediated and cell-mediated injury may operate in the same patient. (2) Only few examples of drug-induced vasculitis and glomerulonephritis are known, and the pathophysiology of this kind of renal damage is poorly understood.

Acute Kidney Injury↗