Search PubMed⌕ Search

Biomedical subjects

V E Pollak

Publications and source records attributed to V E Pollak.

At least 91 records · Page 5Linked to original sources
PubMed1980

Occupational exposure to lead: effects on renal function.

Although nephrotoxicity is common following exposure to lead, the dose-response relationship in adults with occupational exposure is not well understood because information is lacking on early nephrotoxic effects. By the time serum urea nitrogen and creatinine levels are elevated, renal damage may be advanced and not fully reversible. Detailed investigations of renal glomerular and tubular function were performed in six adults with occupational exposure to lead. In all patients, the serum creatinine and urea nitrogen concentrations were within the normal range. GFR was decreased in all but two. Glucose reabsorptive capacity (TmG) was decreased in all, and this decrease was disproportionately greater than expected from the reduced GFR in all but one. Normal values for renal plasma flow (RFP) were observed in four of the six, and for rho-aminohippurate (PAH) secretory capacity (TmPAh) in all but one. Bicarbonate reabsorptive capacity (TmHCO3) and urinary excretion of beta2-microglobulin were normal in all. Routine clinical laboratory tests are insensitive for the detection of early renal effects of heavy metal exposure. Measurements of renal tubular reabsorptive capacity for glucose appears to be a sensitive method for the early detection of renal effect of lead.

Adult↗
PubMed1979

Fractional excretion of sodium after renal transplantation.

After renal transplantation low urinary sodium concentration (UNa) has been used to diagnose acute rejection (AR), for the early phase of AR is often associated with reduced renal perfusion. Early postoperative graft failure without low UNa favors the diagnosis of ischemic tubular damage (ATN). As fractional excretion of filtered sodium (FENa) better reflects glomerulotubular balance in renal sodium handling, FENa was analyzed during the first 2 weeks in 118 renal allografts. From data on 41 transplants with good early renal function (GEF), a temporal profile of FENa was obtained and used to evaluate the behavior of FENa by means of standardized FENa (Z score). Individual subjects followed their own profile with a small deviation (delta Z less than 1.4 for 2 days). In 31 instances, acute rejection was diagnosed. In 14 with AR, the Z score deviated little; 2 responded to methylprednisolone given intravenously. In 17 with AR, the Z score fell significantly (delta Z greater than 1.5 for 2 days), an average of 2.6 days before the first rise in serum creatinine concentration; 15 responded to treatment. The difference between these two groups was significant (P less than 0.001). This functional heterogeneity and different responses to treatment may indicate different immunologic mechanisms which damage different target cells in the graft in AR. In 46 patients with acute tubular necrosis after cadaver kidney transplantation FENa was significantly higher than it was in the GEF group as early as the first posttransplantation day and approached normal as the renal function recovered. This behavior of FENa was clearly different from that in AR.

Antilymphocyte Serum↗
PubMed1979

Nephrotoxicity of low molecular weight serum proteins: physicochemical interactions between myoglobin, hemoglobin, bence-jones proteins and tamm-horsfall mucoprotein.

Three types of low molecular weight serum proteins, myoglobin, hemoglobin and BENCE-JONES proteins, are associated clinically with acute renal failure. All have isoelectric points which render them anionic at blood pH but cationic in the distal nephron under conditions of aciduria. Experiments in which these proteins were mixed with TAMM-HORSFALL mucoprotein in vitro and the pH lowered with lN HCl showed co-precipitation of proteins at pH levels of 5.5 and below. In vivo experiments in which 11 different BENCE-JONES proteins of pl ranging from 5.2 to 6.6 were injected into aciduric, hydropenic rats showed an acute rise in serum urea nitrogen and creatinine concentrations with BENCE-JONES proteins of pl greater than 5.7 compared with little change in rats injected with BENCE-JONES proteins of pl less than 5.7. These data suggest that protein pl and urine pH are important in determining nephrotoxicity; a mechanism by which these low molecular weight serum proteins and TAMM-HORSFALL proteins interact in the distal nephron to initiate acute renal failure in postulated.

Acute Kidney Injury↗
PubMed1978

Pre-eclampsia with the nephrotic syndrome.

Heavy proteinuria and/or the nephrotic syndrome rarely occur late in pregnancy. We report the clinical and renal biopsy findings on 11 patients with the nephrotic syndrome occurring during pregnancy in whom light and electron microscopic findings were characteristic of pre-eclampsia. Immunofluorescent microscopy revealed deposits of IgG, IgM, IgA, beta 1C globulin, and fibrinogen, predominantly in the subendothelial position. Only two patients were primigravid; three were in their second or third pregnancy; in six, pre-eclampsia first occurred in the fourth to eighth pregnancy. Clinical abnormalities appeared first between the 23rd and 39th week of gestation. All patients had marked elevation of blood pressure and of serum uric acid levels. Of the 12 infants, eight were alive and well, including one set of twins; four were stillborn. Following delivery, clinical resolution was similar to that in less severe pre-eclampsia. The findings suggest the possible importance of the role of intravascular coagulation in the genesis of pre-eclampsia.

Adolescent↗
PubMed1978

Albumin excretion by the kidney: the effects of osmotic diuresis.

Urine albumin excretion rate in female Sprague-Dawley rats was measured duing a stable period of normal hydration and following mannitol-induced osmotic diuresis. Mannitol infusion resulted in a significant increase in urine volume and fractional excretion of sodium, but glomerular filtration rate, albumin excretion rate, and the sieving coefficient for albumin remained stable. The results suggest that under physiological conditions, changes in albumin excretion are dependent upon changes in glomerular filtration rather than urine flow.

Albuminuria↗
PubMed1977

Immunofluorescent localization of beta2-microglobulin in the human kidney.

Using antisera to human beta2-microglobulin and an immunofluorescent technique, beta2-microglobulin was found to be localized along tubular and glomerular basement membranes of renal bipsies studied. Since beta2-microglobulin is a subunit of HLA preparations, it may also serve as an indirect marker for the presence of HLA antigens in these structures.

Basement Membrane↗
PubMed1977

Proteinuria following renal transplantation.

Proteinuria was studied in ten renal allograft recipients; it was defined as: (a) glomerular--characterized by predominant albumin excretion; (b) tubular--significant excretion of both albumin and low molecular weight (LMW) proteins; and (c) glomerulo-tubular or mixed type, a combination of the two. LMW protein and albumin were quantitated by polyacrylamide gel electrophoresis with sodium dodecyl sulfate. In the immediate posttransplant period, LMW protein and albumin excretion, expressed as a percentage of creatinine clearance, were high, revealing a mixed pattern, and excretion of both protein classes was higher than during both acute tubular necrosis and acute rejection crisis. Tubular proteinuria was observed in acute tubular necrosis; a glomerulo-tubular or mixed pattern of protein excretion in acute rejection crises.

Adolescent↗
PubMed1977

Circulating immune complexes after renal transplantation. Correlation of increased 125I-Clq binding activity with acute rejection characterized by fibrin deposition in the kidney.

To assess the role of circulating immune complexes in the pathogenesis of acute rejection, sera were measured for such complexes by the (125)I-C1(q) binding assay in 45 normal subjects, 24 allografted patients undergoing acute rejection, and in 11 allografted patients in a quiescent phase. Increased C1(q)-binding activity (C1(q)-BA) was detected in 14 patients with acute rejection, 9 of whom had renal biopsies showing fibrin deposition in the vasculature together with cellular infiltrates in the tubulo-interstitial structures; renal histology was not available in the other 5 patients. The other 10 patients with acute rejection, whose biopsies showed only cellular infiltrates, and the 11 patients in a quiescent phase posttransplantation did not have increased levels of serum C1(q)-BA. Of the group with increased serum C1(q)-BA, serial studies in eight patients showed a correlation between increased serum C1(q)-BA and the occurrence of rejection; with reversal by therapy, serum C1(q)-BA returned to within normal levels. Complexes from six patients were analyzed by sucrose density gradient ultracentrifugation to have sedimentation coefficients ranging from 15S to 18.4S. After acid dissociation and analysis by double-diffusion techniques, C1(q)-reactive complexes were shown to contain IgG. Immunofluorescent studies done in five renal biopsies from this group revealed granular deposits of immunoglobulin, and (or) less frequently, of complement in the glomeruli or the tubular basement membranes. The findings suggest that circulating immune complexes may mediate the type of acute rejection characterized by fibrin deposition in the kidney. The role of circulating immune complexes arising from the recipient's original kidney disease could be excluded in 10 patients with humoral rejection, inasmuch as the underlying renal pathology was of a "nonimmunologic" nature; this was corroborated by sequential studies in six patients in whom circulating immune complexes could not be demonstrated before rejection. The participation of administered antilymphocyte globulin (ALG) as an antigen also appears to be excluded in four patients, two who were not given ALG, and in two of whom episodes of rejection occurred unrelated temporally to ALG administration.

Antigen-Antibody Complex↗
PubMed1977

Lymphocytotoxins in epileptic patients receiving phenytoin.

The present study was undertaken to determine the prevalence and nature of lymphocytotoxic antibodies in patients receiving phenytoin. Of forty-six sera examined, lymphocytotoxins and antinuclear antibodies were detected in fourteen and eleven samples respectively. Antibodies to double-stranded RNA (poly-A-poly-U) were found in six out of thirty-eight sera studied. A highly significant correlation was found between the presence of lymphocytotoxins and antinuclear antibodies (chi2 = 9.72; P less than 0.01). Lymphocytotoxins were found to be of the IgM class, to have activity against T and B cells, and to be dependent on the presence of Ca and Mg ions for activity. These findings may have pathogenetic importance in the genesis of the altered immune state of patients reveiving phenytoin.

Antibodies↗
PubMed1977

On-line computerized data handling system for treating patients with renal disease.

Some patients with renal disease accrue 6,000 to 8,000 individual data items relating to symptoms, signs, laboratory information, and treatment in one year. To deal with the problem of handling so many data items, the following steps were taken: (1) a dictionary of terms peculiar to nephrology was created; (2) manual time-oriented records for nephrology were constructed; and (3) an on-line data processing system, using a PDP-11/70 computer and remote teleprocessing terminal, was developed. On the terminal screen, up to 11 consecutive patient visits can be displayed horizontally, with 18 data items displayed vertically. Up to 30 of the most recent patient visits are easily accessible. For patient treatment, a special feature allows a rearrangement and instantaneous display of any combination of data, thus permitting review of essential feedback relationships between clinical events and treatment.

Data Display↗