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Biomedical subjects

V E Pollak

Publications and source records attributed to V E Pollak.

At least 55 records · Page 3Linked to original sources
PubMed1985

Results of treatment in patients with end-stage renal disease: a multivariate analysis of risk factors and survival in 341 successive patients.

Factors that affect survival in patients with end-stage renal disease (ESRD) are still only partially understood. We report an analysis on a cohort of 341 successive patients who started ESRD treatment in one institution. Survival was calculated from the start of ESRD treatment, whether initial treatment was by dialysis (335 patients) or transplantation (6 patients). Analysis of factors affecting survival was done using the Cox multivariate hazard analysis. Relative risks were calculated for several demographic factors, the primary renal disease, the presence or absence of various high-risk co-morbid factors, and for a first transplant from a living-related or cadaver donor. Older patients, patients with no prior health insurance, those with diabetic nephropathy, and those with small kidneys of unknown cause had statistically significantly higher risks of dying. The risk of dying decreased by year of start of ESRD treatment. Living related donor transplantation was associated with a decreased hazard to age 45 years and older; whereas cadaver donor transplantation was associated with a hazard that increased with age and was significantly increased by age 45.

Actuarial Analysis↗
PubMed1985

Effects of dietary linoleic acid enrichment on induction of immune complex nephritis in mice.

In pharmacologic doses E series prostaglandins attenuate the development of immune complex nephritis. We studied the effect of the dietary prostaglandin precursor linoleic acid on murine apoferritin-induced immune complex glomerulonephritis. High, normal, or low linoleic acid diets were fed to mice for 4 weeks prior to and during the intraperitoneal apoferritin administration. A high linoleic acid diet feeding was associated with less proteinuria, less renal histologic damage, and prevented a rise in serum creatinine. We conclude that linoleic acid has a protective effect on the development of murine apoferritin-induced immune complex nephritis.

Animals↗
PubMed1985

Ancrod: normalization of fibrinolytic enzyme abnormalities in patients with systemic lupus erythematosus and lupus nephritis.

Ancrod is a thrombinlike enzyme from Malayan pit viper (Agkistrodon rhodostoma) venom that has a selective enzyme substrate specificity for fibrinogen. Unlike thrombin, it splits only fibrinopeptide A from the fibrinogen molecule and does not activate factor XIII. Simultaneously with the occurrence of hypofibrinogenemia there is a reduction of plasma plasminogen and a rise in fibrin degradation products, suggesting secondary recruitment of the fibrinolytic enzyme system. Ancrod was given to 18 patients with systemic lupus erythematosus and glomerular and vascular microthrombi. Before treatment vascular plasminogen activator (VPA) was low or unmeasurable in 14, an inhibitor of urokinase-induced plasminogen activation (IPA) was elevated in 18, and an inhibitor of plasmin (PI) was elevated in five. Ancrod treatment resulted in prompt normalization of IPA levels in 13 patients; they were classified as fibrinolysis responders. In five patients IPA levels remained elevated throughout treatment with ancrod; they were classified as fibrinolysis nonresponders. In these five the PI level was elevated before treatment and decreased slowly toward the normal range during ancrod administration. The PI did not appear related to the nonspecific serine protease inhibitors, and was shown to be identical with alpha 2-antiplasmin. In the fibrinolysis responders serial histologic studies showed a striking decrease of disappearance of microvascular thrombosis; in the fibrinolysis nonresponders microvascular thrombosis persisted. The action of ancrod is discussed.

Adult↗
PubMed1985

Thrombosis in systemic lupus erythematosus. Relation to the presence of circulating anticoagulants.

In an earlier report on the kidney in systemic lupus erythematosus (SLE), we described a subset of patients with circulating anticoagulants; many had glomerular and arteriolar thrombosis in the absence of necrosis and subendothelial deposits. The present study extends these observations to a larger group of patients with SLE and a circulating anticoagulant, and compares its findings with those in patients with SLE without evidence of an anticoagulant. It demonstrates (1) a higher prevalence of clinically recognizable thrombotic events in the venous and arterial circulations in patients with SLE and a detectable anticoagulant; (2) a probable shortening in life span; (3) a higher prevalence of glomerular thrombi; (4) elevated levels of factor VIII antigen and von Willebrand factor; and (5) significantly lower platelet counts and decreased in vitro platelet aggregation in response to adenosine diphosphate, epinephrine, and collagen. Since prednisone treatment often results in improvement or disappearance of a prolonged partial thromboplastin time, the test most commonly used for screening of a circulating anticoagulant, we suggest that the prevalence of this abnormality may be underestimated in patients with SLE.

Adolescent↗
PubMed1985

Nephrotic syndrome with renal vein thrombosis: pathogenetic importance of a plasmin inhibitor (alpha 2-antiplasmin).

Tests of fibrinolysis were measured by fibrin plate methods in 44 patients with nephrotic syndrome, in 14 of whom renal vein thrombosis was demonstrated. In both groups the level of total fibrinolytic activity was normal, that of vascular plasminogen activator was decreased, and that of an inhibitor of plasminogen activation was elevated. The level of a plasmin inhibitor, measured by the fibrin plate method, was elevated in 13 of 14 patients with, but only in 12 of 30 without, renal vein thrombosis (p less than 0.005). The plasmin inhibitor was identical with alpha 2-antiplasmin. The data suggest that an increased level of alpha 2-antiplasmin may be a factor in determining susceptibility to the development and persistence of renal vein thrombosis in patients with nephrotic syndrome.

Fibrinolysis↗
PubMed1985

Lupus nephritis with thrombosis and abnormal fibrinolysis: effect of ancrod.

Recent evidence demonstrates that coagulation plays a role in mediating glomerular damage in patients with systemic lupus erythematosus and diffuse proliferative glomerulonephritis. Because of its beneficial effect in experimental glomerulonephritis, we treated patients with systemic lupus erythematosus and diffuse proliferative glomerulonephritis with ancrod, a drug known to lower fibrinogen levels and thought to activate fibrinolysis. Our patients had unusually severe renal disease; renal function was deteriorating in many. Before ancrod, vascular plasminogen activator levels were low, and levels of an inhibitor of plasminogen activation were elevated. Some patients had elevated plasmin inhibitor levels. Results were considered in two groups. In 13 patients characterized as fibrinolysis responders, the low vascular plasminogen activator and increased plasminogen activation inhibitor levels normalized. After ancrod, striking resolution of microvascular thrombosis occurred, which was associated with some improvement in renal function and blood pressure control. In five patients characterized as fibrinolysis nonresponders and who also had an elevated plasmin inhibitor (alpha 2-antiplasmin) level, normalization of fibrinolysis did not occur. There was little change in microvascular thrombosis, renal function, or blood pressure control in the fibrinolysis nonresponders. These preliminary observations demonstrate a disorder of fibrinolysis in patients with systemic lupus erythematosus with microvascular thrombi in the kidney. Ancrod therapy reverses this disorder rapidly in patients with a normal level of plasmin inhibitor and may lead to repair of glomerular damage.

Adolescent↗
PubMed1984

Analysis of humoral and cellular factors that contribute to impaired immune responsiveness in experimental uremia.

An experimental model in rats was developed to define the nature of humoral and cellular factors that contribute to impaired immune responsiveness in chronic renal failure. Addition of uremic rat serum to both normal and uremic lymphocytes significantly suppressed cellular responses, the suppression being more pronounced with uremic lymphocytes. Lymphocytes from uremic rats were only marginally less responsive than normal lymphocytes to concanavalin A stimulation when normal rat serum was added to the cultures, indicating that the cellular factors in impairment were less important than humoral ones. Antibody formation in rat splenocyte cultures to bovine serum albumin was suppressed by addition of uremic serum, but the response to sheep erythrocytes was unaffected. Thus the effect on antibody response in uremic animals is dependent upon the antigen tested.

Animals↗
PubMed1984

Kinetics of oral tolerance: study of variables affecting tolerance induced by oral administration of antigen.

The induction of antigen-specific tolerance by oral administration of hen egg albumin (OVA) was shown to be time- and dose-dependent. The IgE response was the most effectively suppressed by antigen feeding prior to or after parenteral immunization. The effect on IgG response paralleled that observed on the IgE response, but the magnitude of suppression was less pronounced. The IgA response was enhanced rather than suppressed if the interval between feeding and parenteral immunization was short or if the animals were antigen-fed after the intraperitoneal priming.

Administration, Oral↗
PubMed1984

Ancrod in systemic lupus erythematosus with thrombosis. Clinical and fibrinolysis effects.

A patient with systemic lupus erythematosus had severe hypertension, rapidly worsening renal failure, and multiple successive thrombotic cerebrovascular and retinal lesions develop. In a kidney biopsy specimen luminal thrombi were demonstrated in arteries and arterioles, without vasculitic or inflammatory changes. The patient's plasma was markedly deficient in both prostacyclin stimulating factor (PSF) and vascular plasminogen activator (VPA), and also contained a potent inhibitor of in vitro urokinase-induced fibrinolysis. Treatment with ancrod resulted in striking reversal of the progressive renal damage and clinical recovery from the thrombotic cerebrovascular and retinal lesions. This clinical improvement was associated with improved renal histologic appearance, correction of the PSF and VPA deficiencies, and disappearance of the urokinase inhibitor. Possible mechanisms of action of ancrod are discussed.

Acute Kidney Injury↗
PubMed1984

Fibrinolysis in health and disease: severe abnormalities in systemic lupus erythematosus.

Methods are described to measure fibrinolysis in healthy persons and in patients with systemic lupus erythematosus. Using the fibrin plate method, total fibrinolytic activity and vascular plasminogen activator were measured. (Total fibrinolytic activity expresses the fibrinolytic potential and consists of both the intrinsic [factor XII-dependent and independent] activities and the extrinsic activities [vascular or tissue type]. Vascular plasminogen activator, assessed in a separate assay, refers to the endothelium-derived component only.) In addition, the degree of inhibition by plasma of both urokinase-induced and of plasmin-induced fibrinolysis were analyzed. Vascular plasminogen activator levels were low in 63% of plasma samples from 55 patients with systemic lupus erythematosus. The level of an inhibitor of plasminogen activation was significantly elevated in 87% of patients and levels of an inhibitor of plasmin were significantly elevated in 29%. The nonspecific serine protease inhibitors, including alpha 2-macroglobulin, were within the normal range in all patients. The natures of inhibitor of plasminogen activation and plasmin inhibitor were studied further. Using both the fibrin plate and the lysis time methods, the data indicated that the urokinase-inhibiting activity increased with time of incubation of plasma-enzyme mixtures, whereas the plasmin inhibiting activity did not. Elevated levels of plasmin inhibitor measured with the fibrin plate method correlated well with prolonged lysis times. Results using the chromogenic substrate S-2251, commonly used as a simple and specific assay for antiplasmin, agreed reasonably well with those using the fibrin plate method, but elevated plasmin inhibitor levels could be quantitated with greater accuracy and sensitivity by the fibrin plate method. Studies with an antiserum directed against alpha 2-antiplasmin showed that inhibitor of plasminogen activation and plasmin inhibitor were different inhibitors, and that plasmin inhibitor was identical to alpha 2-antiplasmin. The abnormalities are discussed in the light of current knowledge on fibrinolysis and as possible mediators in the pathogenesis and perpetuation of lupus glomerulonephritis.

Adult↗
PubMed1984

Abnormalities of fibrinolysis in essential hypertension.

A highly-standardized plate method was used to study fibrinolytic profiles in 14 patients with essential hypertension and 245 normotensive healthy control subjects. Compared with the normotensive group, the group with essential hypertension showed a defect in fibrinolysis, as evidenced by a significant increase in the mean level of inhibitor of plasminogen activation, and a subset of the hypertensive patients also showed a significant decrease in the mean level of vascular plasminogen activator. There were no significant differences between the two groups in relation to plasma fibrinogen level, total fibrinolytic activity and plasmin inhibitor. The alterations in inhibitor of plasminogen activation and vascular plasminogen activator in the patients with essential hypertension may reflect a defect in the fibrin-clearing mechanism and, perhaps, contribute to the vascular complications of hypertension.

Adult↗
PubMed1983

Computerization of the medical record: use in care of patients with endstage renal disease.

An on-line computerized medical record system that has been in use for over 5 years is described. Manual forms are a time-oriented problem and event list, a time-oriented record for renal failure, and records for hemodialysis and peritoneal dialysis. The data are entered directly from the forms into the computer. Individual data can be rearranged for display in predetermined or in previously unanticipated ways. Automatic short- and long-term summaries of data on individual patients are available virtually instantaneously. The system has greatly facilitated patient care and the quality control of patient care.

Computers↗
PubMed1983

Induction of oral tolerance in mice unresponsive to bacterial lipopolysaccharide.

C3H/HeJ lipopolysaccharide (LPS)-unresponsive and closely related C3H/HeSn LPS-responsive mice were rendered tolerant to hen albumin by antigen feeding before parenteral immunization. Both single and multiple feedings of antigen were effective in inducing tolerance to hen albumin in LPS-responsive and -unresponsive strains of mice. Our data demonstrate that ability to respond to LPS is not a prerequisite for induction of oral tolerance to a soluble protein antigen.

Albumins↗