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Biomedical subjects

A Iaina

Publications and source records attributed to A Iaina.

At least 19 recordsLinked to original sources
PubMed1992

Severe defect in clearing postprandial chylomicron remnants in dialysis patients.

Lipid abnormalities have been suggested as a major cause of the accelerated atherosclerosis and the high incidence of coronary heart disease in chronic renal failure patients. In the present work the postprandial lipoprotein metabolism was studied in chronic dialysis patients with or without fasting hypertriglyceridemia using the vitamin A loading test. This method investigates specifically postprandial lipoprotein metabolism. The determination of vitamin A ester level retinyl palmitate (RP) differentiates the circulating plasma chylomicron and chylomicron remnant fractions from the endogenous VLDL and IDL. Subjects with normal renal function with or without fasting hypertriglyceridemia served as control groups. Dialysis patients have significantly higher level of chylomicron remnants for a more prolonged period of time than controls, irrespective of their fasting triglyceride levels. The area below retinyl palmitate chylomicron remnants curve was 26308 +/- 12422 micrograms/liter.hr in the normolipidemic dialysis patients, significantly higher than (6393 +/- 2098 micrograms/liter.hr; P < 0.0001) in the normolipidemic controls. The retinyl palmitate chylomicron remnants curve of the hypertriglyceridemic dialysis patients was 21021 +/- 4560 micrograms/liter.hr, which was higher than 12969 +/- 2215 micrograms/liter.hr (P < 0.0001) in the hypertriglyceridemic controls. Moreover, the hypertriglyceridemic dialysis patients had an additional defect in the lipolysis metabolic step, that is, accumulation of chylomicrons in circulation. These findings show a severe defect in postprandial lipoprotein metabolism in chronic renal failure patients. The prolonged exposure of the vascular wall to high chylomicron remnant concentrations might be an important pathogenetic factor in the accelerated atherosclerosis seen in chronic dialysis patients.

Adult↗
PubMed1992

Early diagnosis of gram-negative peritonitis in continuous ambulatory peritoneal dialysis patients with the Lymulus amebocyte lysate assay.

The treatment of peritonitis in continuous ambulatory peritoneal dialysis patients is empiric until the bacteriological results are available. The Lymulus amebocyte lysate assay (LAL) is a very sensitive method for the detection of endotoxin, a structural component of gram-negative bacteria. We performed the LAL assay in a prospective study in 36 consecutive episodes of peritonitis. The LAL assay was positive in all 10 episodes of gram-negative peritonitis (100% specificity). Treatment directed specifically against gram-negative or -positive infection was started based on the LAL assay result. In 26 episodes with LAL-negative test, a gram-positive bacterium was cultured in 23 episodes, in 1 there was fungal infection and 2 were sterile. In summary: the LAL assay is a rapid (1 h) and sensitive method for the differentiation of gram-positive or -negative peritonitis and enables starting an immediate and more appropriate antibiotic therapy.

Endotoxins↗
PubMed1992

Normal renin-aldosterone-insulin and potassium interrelationship in FMF patients and amyloid nephropathy.

The renin-aldosterone system and plasma insulin were studied in 19 patients with familial Mediterranean fever (FMF). Their relationships to serum potassium level at rest and before and after oral glucose loading are described. An interesting finding is the occurrence of hyperkalemia in the absence of oliguria, in the advanced stages of renal failure. No differences were found in the activity of the renin-angiotensin-aldosterone system to explain these variations in serum potassium found in some of the patients. The response of the renin-aldosterone system to glucose loading showed no abnormality, and the regular relationship between serum potassium, plasma renin activity (PRA), aldosterone, insulin, and plasma pH is maintained. Levels of insulin, potassium, and bicarbonate in serum or plasma pH were found similar in FMF patients with normal renal function with and without proteinuria. Further decrease in renal function due to the progression of the underlying disease is manifested by an increase in FENa+ and FEK+ and a hyperchloremic metabolic acidosis, as is the case in other patients with chronic renal failure.

Adult↗
PubMed1979

Retinal manifestations in familial juvenile nephronophthisis.

Three families affected by juvenile nephronophthisis are described and genetically analyzed. The extrarenal manifestations of the disease include retinal findings such as congenital Leber amaurosis, retinitis pigmentosa and sector retinitis pigmentosa. Autosomal recessive transmission and the wide phenotypic spectrum are discussed. The variability in the retinal findings is explained by the presence of a pleiotropic gene with variable expressivity.

Adolescent↗
PubMed1979

The effect of propranolol on renal sodium handling in patients with cirrhosis.

Beta-adrenergic blockade by oral propanolol in five cirrhotic patients caused changes in the handling of an acute sodium load. Fractional sodium excretion following an acute saline load increased from 0.69% +/- 0.29 to 1.49% +/- 0.11 (103 microEq/min +/- 7.5 to 129 microEq/min +/- 18) before propranolol administration. After 3 days of oral propanolol 1 mg/kg day, the fractional excretion of sodium by saline loading increased from 0.52% +/- 0.19 to 2.17 +/- 0.19 (109 microEq/min +/- 9 to 178 microEq/min +/- 11). This change was not accompanied by changes in GFR, RPF or in the renin-aldosterone system. The possibility that these changes are caused by a change in the sodium transport at the tubular cell level induced by the beta-adrenergic blockade, is entertained.

Adult↗
PubMed1979

Autonomic nervous system disturbance in patients on chronic hemodialysis.

To demonstrate autonomic nervous system (ANS) disturbances in patients on chronic intermittent hemodialysis, simple noninvasive tests were used. These included the Valsalva maneuver ratio, measurement of the changes in blood pressure and pulse rate following standing up from the supine position, the finger-immersion test and calculating the R-R interval ratio of the 30th to the 15th beat on the ECG following standing. It was found that in all the patients who were compared with normal volunteers, some ANS disturbances were present, as evidenced by at least three positive tests of the five described. The Valsalva maneuver ratio was positive in only 58% of the cases, possibly because it is a less sensitive test than the others.

Adolescent↗
PubMed1979

Dialysis requirements in Israel.

Chronic dialysis is available in Israel to almost all patients who require it. During the last four years the mean number of new patients/million population per year was 44.5 (range, 39.5 to 48.6), excluding patients with systemic diseases such as diabetes mellitus and lupus erythematosus. This number is close to that estimated in a previous study--53/million per year for the years 1965-66--and the discrepancy is probably methodological in nature. The stage of equilibrium for Israel, when the net gain in patients per year approaches zero, as forecast by the European Dialysis and Transplant Association, will be reached in 1983 with 261 dialysis patients/million population. At present, the number is about 171. Inadequately treated hypertension was found to considerably affect long-term survival.

Adolescent↗
PubMed1978

Proximal renal tubular acidosis: association with familial normaldosteronemic hyperpotassemia and hypertension.

Further investigation of a family with normaldosteronemic hyperpotassemia and low-renin hypertension showed seven members from three generations, who ranged in age from 4 to 56 years, to be affected. Results of earlier studies had established a normally functioning renin-aldosterone system and normal renal handling of potassium. Constant, albeit mild and asymptomatic, metabolic acidosis in all those affected prompted bicarbonate loading in both the propositus and his brother, which revealed a maximal renal tubular excretory capacity for bicarbonate reabsorption at serum levels of 18 mmole/liter and proved proximal renal tubular acidosis (PRTA). Further, a linear increase in urinary fractional potassium excretion accompanied that of bicarbonate in both, as in normal individuals. Dextrose-insulin infusion in the brother failed to reduce hyperpotassemia. These data support the hypothesis that a generalized cell membrane defect that specifically impedes potassium influx (as opposed to an isolated renal tubular defect) underlies this autosomal dominant disorder.

Acidosis, Renal Tubular↗
PubMed1978

Presence of insulin-renin-aldosterone-potassium interrelationship in normal subjects, disrupted in chronic hemodialysis patients.

The factors regulating aldosterone secretion in normals and in patients on chronic hemodialysis were studied by the determination of the circadian rhythm of plasma aldosterone, renin, cortisol, insulin, potassium, sodium, and glucose. Four normal volunteers and eight normotensive patients on regular dialysis treatment (RDT) were studied during prolonged recumbency on low sodium diet. A definite circadian rhythm for renin could not be demonstrated in RDT patients. The significant simple and multiple correlation coefficients found in normal subjects suggest that insulin participates in the regulation of aldosterone together with the other known factors: ACTH, renin, and potassium. In chronic renal failure, however, when basal conditions were maintained during prolonged recumbency, the correlations of insulin and renin with aldosterone were not found, suggesting that in this condition aldosterone secretion is controlled by ACTH and potassium. As a direct influence of insulin on aldosterone could not be demonstrated by multiple variance analysis, it seems that insulin is related to aldosterone indirectly through renin and/or potassium. The presence of significant correlations between insulin-potassium and potassium-aldosterone in RDT patients, without a significant insulin-aldosterone correlation, suggest that in the normals insulin participates in aldosterone regulation through renin secretion and not through potassium. A correlation between potassium and renin was not found in normals or in RDT patients.

Adult↗
PubMed1978

High renal plasma flow lability in the kidneys of hypertensive patients.

The spontaneous changes in renal plasma flow (RPF) were determined by sodium paraamino hippurate clearance (CPAH) in the individual kidneys of 71 patients with essential and secondary hypertension. These changes were expressed as changes in CPAH and as changes in CPAH per 100 ml Glomerular Filtration Rate (GFR = inulin clearance) for every individual kidney. Sixteen normal subjects were used as control. The RPF changes were measured between two consecutive 10 minute clearance periods during separated kidney function tests. In all the hypertensive groups studied, when RPF variability was expressed per 100 ml GFR, the variability was found to be two to five times greater than in normals. This findings suggests that in the hypertensive state the blood flow changes in the kidney are more labile than in normals. The high lability of renal blood flow could reflect and abnormality in renal vascular tone. This abnormality could be an important factor in the pathogenesis and maintenance of high blood pressure.

Adult↗
PubMed1978

Familial hyperpotassemia and hypertension accompanied by normal plasma aldosterone levels: possible hereditary cell membrane defect.

Hypertension and hyperpotassemia that were accompanied by normal plasma aldosterone and low renin levels and were responsive to chlorothiazide administration were found in a 29-year-old patient and two decades later in his 21-year-old son. Their renal function is normal, including response to sodium sulfate, mannitol, and aldosterone infusions. Adrenal insufficiency was excluded. The renin-aldosterone system was proved intact by physiological and pharmacologic stress and angiotensin-II infusion. Also normal were values for blood counts, blood volumes, and erythrocyte and exchangeable body potassium. The postulation of a defective cell membrane impeding potassium influx is supported by the failure of glucose and insulin infusions to substantially reduce hyperpotassemia. In the context of a hereditary disorder (the pedigree, compatible with autosomal dominant inheritance, includes five affected in two generations), hypertension is a second phenotypic character of a single defective pleiotropic gene although its pathogenesis remains unclear.

Adult↗