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Biomedical subjects

U Gafter

Publications and source records attributed to U Gafter.

At least 91 records · Page 5Linked to original sources
PubMed1990

Successful pregnancies in women on regular hemodialysis treatment.

Successful pregnancies in women on regular hemodialysis treatment are infrequent but increasing. We present two such cases; both pregnancies were diagnosed early, and hemodialysis was intensified, leading to significant reductions in predialysis serum urea levels (70-100 mg/dl). One case was particularly unusual in that systemic lupus erythematosus was the underlying disease, and the patient had no residual renal function at the time of conception. Both patients delivered by cesarean section at 32 and 35 weeks, and their infants are well at ages 2 years and 18 months, respectively. The management and the complications associated with such pregnancies are discussed.

Adult↗
PubMed1989

Brainstem auditory evoked responses in rats with experimental chronic renal failure.

1. Chronic renal failure was induced in rats by five-sixths nephrectomy. Brainstem auditory evoked response (BAER) was recorded after 3 months. 2. In the uraemic rats latency of the first wave was delayed, while the interpeak I-V latency was similar to that of the controls. 3. These results suggest a delayed neural conduction along the acoustic nerve or cochlear changes in uraemic rats.

Animals↗
PubMed1989

Enalapril attenuates glomerular hyperfiltration following a meat meal.

It has been shown that the glomerular filtration rate increases after a meat meal. We examined in humans whether enalapril, which has been shown to decrease glomerular capillary pressure in rats with chronic renal failure, could attenuate the renal response to a meat meal. Twelve healthy volunteers were studied after an oral protein load, 1.5 g/kg body weight, as lean cooked beef meat, and on a separate day, after eating the same meal with prior oral intake of enalapril. On the control day, creatinine clearance increased from 114.3 +/- 4.7 before the meal to 137.1 +/- 4.7 ml/min/1.73 m2 after the meal (p less than 0.001). On the enalapril intake day, creatinine clearance increased from 113.7 +/- 5.6 before the meal to 128.3 +/- 5.8 ml/min/1.73 m2 after the meal (p less than 0.01). However, the mean increase in creatinine clearance was lower on the enalapril intake than on the control day (14.0 +/- 4.3 vs. 21.0 +/- 4.1%, p less than 0.05). Mean arterial pressure before the meal was lower on the enalapril intake day than on the control day (76.2 +/- 3.5 vs. 84.2 +/- 3.6, p less than 0.01). Likewise, postprandial mean arterial pressure was lower on the enalapril day compared with the control day (69.9 +/- 2.8 vs. 78.5 +/- 3.7, p less than 0.01). We conclude that enalapril blunts the hyperfiltration which follows a meat meal.

Adult↗
PubMed1989

Brainstem auditory evoked responses in chronic renal failure and the effect of hemodialysis.

Brainstem auditory evoked responses (BAER) were recorded in patients with chronic renal failure before commencement of chronic dialysis treatment, and in patients with end-stage renal failure on chronic hemodialysis for several years. Both groups of patients had delayed latencies of the third and fifth waves. The patients on hemodialysis revealed delayed latency of interpeak I-V as well. There was no correlation between wave latency, serum urea, creatinine, PTH or duration of chronic hemodialysis treatment. A hemodialysis session led to a slight shortening of the third wave. This study suggests that neural conduction along the brainstem in patients with chronic renal failure is delayed even before hemodialysis is started. Although 1 dialysis session may have some beneficial effect, long-term hemodialysis treatment does not seem to shorten the delay in neural conduction observed in patients with chronic renal failure.

Adolescent↗
PubMed1989

Red blood cell calcium homeostasis in patients with end-stage renal disease.

Low cell calcium level is essential for preservation of red blood cell (RBC) membrane deformability and survival. RBCs from patients with end-stage renal disease (ESRD) demonstrate reduction in membrane deformability, possibly as a result of increased RBC cellular calcium level. To evaluate calcium homeostasis in RBCs from patients with ESRD, we measured cell calcium level, basal and "calmodulin"-stimulated calcium-stimulated Mg-dependent ATPase (CaATPase) activity, and calcium 45 efflux were measured before and after hemodialysis. The in vitro effect of uremic plasma and of urea on CaATPase activity of normal RBCs was tested, and 45Ca influx into RBCs of patients undergoing hemodialysis also was determined. A morphologic evaluation of red cells from patients with ESRD was performed with a scanning electron microscope. RBC calcium level in patients (mean +/- SEM 21.2 +/- 2.8 mumol/L of cells; n = 28) was higher than in controls (4.9 +/- 0.3 mumol/L of cells; n = 24; p less than 0.001). Hemodialysis had no effect on cell calcium level. Both basal and "calmodulin"-stimulated RBC CaATPase activities in patients with ESRD (n = 9) were reduced by approximately 50% (p less than 0.01), but after hemodialysis, enzyme activity returned to normal. 45Ca efflux from calcium-loaded cells, which was 2574.0 +/- 217.0 mumol/L of cells per 0.5 hours before hemodialysis, increased to 3140.7 +/- 206.8 mumol/L of cells per 0.5 hours after hemodialysis (p less than 0.005). In vitro incubation of normal RBCs with uremic plasma depressed CaATPase activity, but incubation with urea had no effect. RBCs of patients with ESRD revealed increased 45Ca influx, 7.63 +/- 1.15 mumol/L of cells per hour versus 4.61 +/- 0.39 mumol/L of cells per hour (p less than 0.025). RBCs of patients revealed a high incidence of spherocytosis and echynocytosis, which correlated with a high cell calcium level (r = 0.894, p less than 0.01). These results indicate that RBC calcium level is elevated in patients with ESRD and suggest that a dialyzable uremic factor inhibits RBC CaATPase activity and thereby calcium efflux, which may account for the elevated cell calcium level. The increased calcium influx further increases cellular calcium level. These abnormalities are associated with spherocytosis and echynocytosis and may contribute to the shortened survival of RBCs in uremia.

Adult↗
PubMed1989

Thrombocytopenia associated with hypersensitivity to ranitidine: possible cross-reactivity with cimetidine.

A rare case of thrombocytopenia associated with ranitidine is described. The thrombocytopenia was accompanied by eosinophilia and slightly elevated serum IgE. The platelet and eosinophilic counts returned to normal as soon as the drug was stopped. Cell-mediated immunity (CMI) determined in vitro by the leukocyte migration inhibition factor test was found against ranitidine and cimetidine. IgE antibody response against both drugs was also found by the mast cell degranulation test. These data suggest an association between the ranitidine-induced thrombocytopenia and both humoral antibody response and CMI. Cross-reactivity between the two H2-receptor antagonists is suggested, as well.

Cell Migration Inhibition↗
PubMed1989

Amyloid goiter.

A case of a 50-year-old patient suffering from secondary amyloidosis presenting with amyloid goiter is described. The diagnostic and therapeutic implications are reviewed.

Amyloidosis↗
PubMed1989

Hypouricemia due to familial isolated renal tubular uricosuria. Evaluation with the combined pyrazinamide-probenecid test.

A Jewish Iraqi woman with familial isolated renal tubular uricosuria, urate clearance of 60.5 +/- 5.7 ml/min and hypouricemia of 1.0 +/- 0.2 mg/dl is described. The combined pyrazinamide-probenecid test suggested a presecretory defect in urate reabsorption. Four offspring were moderately affected. This family represents the sixth Jewish Iraqi family with familial isolated presecretory uricosuria, and emphasizes the marked prevalence of this disease among the Iraqi Jewish population. Since the inheritance of the presecretory defect is autosomal recessive, we suggest that this family is an example of pseudodominant transmission. The combined pyrazinamide-probenecid test may cause a reduction in glomerular filtration rate and filtered load of urate and thereby affect urinary excretion rate of urate in patients with urate wasting.

Creatinine↗
PubMed1988

Sialic acid and neuraminidase activity in rat kidneys 6 months after uninephrectomy.

Sialic acid and neuraminidase activity were determined in the cortex of the remnant kidneys of six uninephrectomized rats. As controls served either the kidneys removed at operation or age-matched kidneys from eight sham operated rats. Six months after uninephrectomy the kidneys became hypertrophied and their mean weight was about 40% higher than age-matched kidneys. Blood urea and creatinine and protein levels in 24-hr urine collections were significantly higher in the experimental animals as compared to those of the same animals before nephrectomy and to sham operated rats, indicating a marked impairment of kidney function. The mean concentration of sialic acid in the cortex of hypertrophied kidneys was not statistically different from either that of the removed or that of the age-matched kidneys. Neuraminidase activity expressed as either per gram fresh tissue or per milligram protein, was not different in the removed and in the hypertrophied kidney. The activity, however, in the latter was significantly lower than in the age-matched kidneys. Whether this finding can be associated with the impairment of kidney function in rats 6 months after uninephrectomy remains to be studied.

Animals↗
PubMed1987

Platelet count and thrombopoietic activity in patients with chronic renal failure.

The frequency of thrombocytopenia in patients with chronic renal failure (CRF) is controversial. This study was undertaken to investigate the platelet count in 55 patients with end-stage renal disease on maintenance hemodialysis and in 19 patients with CRF before hemodialysis had begun. In both groups platelet counts were similar and significantly reduced, 175,000 +/- 6,500 and 181,000 +/- 10,800 compared to 253,000 +/- 3,700/mm3 in the control (p less than 0.0001). 31% of hemodialysis patients had thrombocytopenia (platelet count less than 150,000/mm3). The megakaryocyte number in their bone marrow aspirate was not reduced. Primary renal disease, androgen treatment or parathyroidectomy did not affect the platelet count. Thrombopoietic activity using 75Se-selenomethionine incorporation into platelets measured in 7 thrombocytopenic patients was found to be reduced, 6.77 +/- 0.29 vs. 9.06 +/- 0.27 (X 10(-2)%: p less than 0.001). This study shows that the platelet count is reduced and mild thrombocytopenia is frequent in patients with CRF. A possible cause for the platelet count reduction is insufficient thrombopoietic activity.

Adolescent↗
PubMed1986

Acute renal failure in a solitary kidney due to bacterial pyelonephritis.

Deterioration of renal function after acute bacterial pyelonephritis is rare. We report on 2 patients with a solitary functioning kidney in whom acute renal failure developed in the setting of acute bacterial pyelonephritis. Following antimicrobial treatment kidney function returned to baseline values. This finding suggests that patients with a solitary functioning kidney are more prone to have renal dysfunction after acute bacterial pyelonephritis.

Acute Kidney Injury↗
PubMed1986

Response of spontaneously hypertensive rats to 1,25(OH)2D3 in vivo.

Calcium absorption in spontaneously hypertensive rats (SHR) has been reported to be increased, decreased or not different from their normotensive Wistar Kyoto (WKy) control. One postulated reason for these conflicting results is an abnormal sensitivity to the intestinal effects of 1,25(OH)2D3 (1,25D3). Previous studies in everted duodenal sacs and perfused duodenum examined the acute response to 1,25D3 only in 12-week-old SHR, which however already had higher basal rates of calcium absorption. Inability to stimulate Ca absorption further was an unexcluded possibility. To test this hypothesis more vigorously, balance and in situ duodenal 45Ca uptake studies were performed in SHR and WKy using four separate protocols yielding the following results. First, in response to pharmacological doses of 1,25D3 (25 ng/100 g body wt/day X 3), four-week-old normotensive female SHR had higher net calcium absorption (41.4 vs. 31.1 mg/day; 61.6 vs. 48.1%), similar to the increases seen in the untreated state. These results suggest intrinsic epithelial differences independent of 1,25D3. Ca absorption was similarly higher in 1,25D3 treated male SHR (42.9 vs. 36.7 mg/day; 60.1 vs. 53.7%). Second, at 12 to 14 weeks of age, low doses of 1,25D3 (8 ng/100 g body wt/day X 6) stimulated net Ca absorption in the female SHR (33.0 to 39.1 mg/day), but not in WKy (26.8 to 29.3 mg/day). In the male, positive effects were again seen only in the SHR (25 to 45 mg/day). Third, in response to three weeks of dietary Ca deprivation, in situ duodenal 45Ca uptake, measured in the conscious awake state, was higher in 35-week-old SHR (70.9 vs. 53.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1986

Chronic DOCA treatment increases Ca absorption: role of hypercalciuria and vitamin D.

To examine the effects of mineralocorticoidism on calcium (Ca) absorption and to define the mechanism, rats received a high-salt diet and injections of vehicle or deoxycorticosterone acetate (DOCA). Net (44.2 vs. 31.4 mg/day) and percent Ca absorption (28.1 vs. 20.1%) was increased after 5 days of DOCA. This was associated with increased duodenal 45Ca uptake. Thus despite the hypercalciuria, Ca balance was similar. Although the hypercalciuria persisted chronically, the gut effects were sustained, which maintained normal ionized Ca, bone Ca, and Ca balance. Urinary cyclic adenosine monophosphate was elevated by DOCA. Compared with appropriate controls, neither DOCA alone nor polydipsia (elicited by dextrose) produced similar magnitudes of hypercalciuria as DOCA plus high-salt diet. These maneuvers also failed to increase Ca absorption. Neutralization of the metabolic alkalosis neither attenuated the DOCA-induced hypercalciuria nor abolished the Ca hyperabsorption. In vitamin D-deprived rats, the hypercalciuria but not the intestinal effects of DOCA were reproduced. Serum 1,25-dihydroxyvitamin D3 levels were increased during chronic DOCA treatment (224 vs. 139 pg/ml). These data best fit the hypothesis that increased Ca absorption is secondary to the calciuric effects of DOCA and high-salt diet and is mediated via the increased parathyroid hormone and 1,25-dihydroxyvitamin D3 activities.

Alkalosis↗