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Biomedical subjects

M Aladjem

Publications and source records attributed to M Aladjem.

At least 19 recordsLinked to original sources
PubMed1992

Effects of essential hypertension and antihypertensive medications on sweat formation.

OBJECTIVE: Sweat volume and ionic composition depend to a large extent upon the cytosolic free calcium level in secretory sweat cells and sodium and potassium transport in the reabsorptive sweat duct. Since essential hypertension and its treatment with antihypertensive drugs is likely to be associated with altered cellular ionic regulation, the objective of this research was to explore sweat formation and sweat parameters in hypertensive and normotensive subjects. DESIGN: Black and white hypertensive and normotensive subjects of both genders were studied. Essential hypertensives were on or off antihypertensive medication. METHODS: Pilocarpine iontophoresis was used to induce sweat in a 5-cm2 area of the middle forearm. Sweat was analyzed for volume, sodium and potassium concentrations. RESULTS: Females demonstrated lower sweat volumes after pilocarpine stimulation than males. Untreated hypertensive white males exhibited a higher pilocarpine-induced sweat volume and sweat sodium excretion than normotensive white males, whilst hypertensive white males on antihypertensive medication showed a lower sweat volume and sweat sodium excretion than both normotensive white males and untreated essential hypertensive white males. Although untreated hypertensive white females did not show significant alterations in sweat parameters, treated hypertensive white females exhibited lower sweat volume and sweat sodium excretion than both the normotensive and untreated essential hypertensive white females. These hypertension and drug related alterations were not present in hypertensive black males and females. CONCLUSIONS: The results are consistent with the heterogeneous nature of essential hypertension and the diversity of the response to antihypertensive therapy. They suggest that the effect of antihypertensive medication on sweat formation is mediated through cytosolic free calcium.

Adult↗
PubMed1992

Brainstem auditory evoked potentials in familial dysautonomia.

The brainstem function of eight children with familial dysautonomia was investigated by brainstem auditory evoked potentials and compared with that of age-matched healthy control children. All median latencies of waves III and V in the study group were significantly higher than those of the control children. Brain transmission times of waves I-III and I-V were significantly prolonged in the study group compared with the control group. These results provide additional objective support for the assumption that the brainstem function of children with familial dysautonomia is affected by this disease.

Adolescent↗
PubMed1992

The effect of prenatal administration of dexamethasone and ritodrine on cord blood cortisol and glucose concentrations in premature infants with respiratory distress syndrome.

The influence of maternal dexamethasone and ritodrine administration during pregnancy on cord blood cortisol and capillary serum glucose concentrations and on the incidence of respiratory distress syndrome (RDS) was studied in 30 premature infants (gestational age 27-36 weeks), and compared with a matched control group of 37 premature infants where no such medications were administered. RDS occurred less often in the treated group of infants (13.3%) than in the controls (35.1%, p < 0.01). The healthy treated infants had a significantly lower mean umbilical cord plasma cortisol concentration (5.5 +/- 1.8 ug/dl, mean +/- SD) than that observed in the controls (11.2 +/- 3.9 ug/dl, p < 0.01). Mean cord plasma cortisol concentrations increased with duration of pregnancy. No significant difference in the capillary serum glucose at 30 minutes post-delivery was found between the healthy, RDS, treated and non-treated infants. No adverse effects of steroid and ritodrine therapy were observed.

Blood Glucose↗
PubMed1991

Autosomal recessive lethal infantile cytochrome C oxidase deficiency.

Three bedouin children with mitochondrial myopathy due to cytochrome c oxidase deficiency presented with progressive muscle weakness, failure to thrive, proximal renal tubular acidosis, and lactic acidemia leading to death. Two died by age 5 months and one by age 16 months. Cytochrome c oxidase was markedly reduced in skeletal muscle extracts of all three. Three other children of the same family with most probably the same metabolic aberration are also described. We suggest an autosomal recessive inheritance for this lethal mitochondrial myopathy.

Acidosis, Renal Tubular↗
PubMed1991

PNM: a program for parametric and nonparametric mapping of multidimensional data.

A program named PNM is presented for the mapping of multidimensional data within a two-class classification problem. A novel mapping method is used for the purpose. The computing procedure implemented in the program is described in detail. Definitions and examples of the control instructions of the program are given at length. An application of PNM for classifier design concerning differential diagnoses of the cerebrovascular accident is presented. It confirms the efficiency of the program in solving classification problems of relatively large size on a small computer.

Brain Ischemia↗
PubMed1990

Functional upper airway obstruction in adolescents.

Functional upper airway obstruction is an uncommon manifestation of a conversive reaction characterized by recurrent stridor attacks caused by adduction of the vocal cords during inspiration. The oxygen saturation never drops to pathologic levels. The stridor is not accompanied by an appropriate degree of anxiety and is not associated with other symptoms. Patients benefit from verbal reassurance and speech therapy, but stridor attacks tend to recur and psychiatric consultation seems necessary in most cases. We present the case histories of three adolescent patients with nonorganic upper airway obstruction and describe the features that may facilitate the diagnosis of this condition. Early diagnosis and intervention may prevent unnecessary and potentially harmful investigations and therapy.

Adolescent↗
PubMed1990

Recurrent seizures in children with Shigella-associated convulsions.

Fifty-five children with Shigella-associated convulsions were followed prospectively to investigate their risk of subsequent febrile or nonfebrile seizures. The duration of the follow-up period was between 6.9 and 14.1 years (9.7 +/- 3.1 years). No case of nonfebrile seizures and only 2 cases (3%) of subsequent febrile seizures were observed during this period. We conclude that although febrile and Shigella-associated convulsions share many clinical features, the natural history of these two conditions seems to be distinctly different. Shigella-related convulsions are not associated with an increased incidence of subsequent febrile or nonfebrile convulsions.

Child↗
PubMed1990

Essential hypertension in blacks: epidemiology, characteristics, and possible roles of racial differences in sodium, potassium, and calcium regulation.

Racial differences in the regulation of Na+, K+, and Ca2+ have been shown both at the systemic and cellular levels. These include a higher incidence of "salt sensitivity," lower urinary K+ excretion, lower plasma renin activity, and higher circulating levels of immunoreactive parathyroid hormone and 1.25 dihydroxyvitamin D in blacks than in whites. Blacks exhibit a higher erythrocyte Na+ concentration, coupled with a lower maximal initial reaction velocity of erythrocyte Na,K-ATPase. Blacks also appear to differ from whites in erythrocyte Na+, K+ cotransport and Na-Li countertransport. Moreover, they show a higher activity of the Na(+)-H+ antiport in skin fibroblasts and a greater response of cellular Ca2+ signaling to agonists in serum. Mechanisms linking some of these racial differences in ionic metabolism to the increased propensity of blacks to develop essential hypertension are proposed, and the epidemiology and characteristics of this disease in blacks are reviewed.

Antihypertensive Agents↗
PubMed1990

Variations in the apparent pH set point for activation of platelet Na-H antiport.

To explore the role of the Na-H antiport in essential hypertension, we studied the kinetics of cytosolic pH and external sodium activation of this transport system in platelets from 65 normotensive and essential hypertensive subjects on and off antihypertensive medications. Subjects included both blacks and whites, as well as men and women. The fluorescent dye 2'7-bis(carboxyethyl)-5,6-carboxyfluorescein was used to monitor the cytosolic pH in these cells. Platelets from black (hypertensive and normotensive) men and hypertensive white men demonstrated a highly significant alkaline shift in the apparent cytosolic pH set point for activation of the Na-H antiport. For the hypertensive subgroups, the cytosolic pH set point values (mean +/- SEM) were: white men, 7.45 +/- 0.052; white women, 7.04 +/- 0.089; black men, 7.66 +/- 0.148; and black women, 7.20 +/- 0.082. For the normotensive subgroups, the cytosolic pH set point values were: white men, 7.13 +/- 0.034; white women, 7.05 +/- 0.036; black men, 7.50 +/- 0.110; and black women, 7.20 +/- 0.176 (p = 0.0016 for race and p = 0.0001 for gender, using a three-way analysis of variance by race, gender, and hypertension). There were no race-, gender-, or blood pressure-related differences among the various cohorts in the kinetics of sodium activation of the Na-H antiport, the cellular buffering power, and basal pH. These results suggest that at basal pH the Na-H antiport is quiescent in platelets from both black and white women and normotensive white men.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1990

Refined estimation of kinetic parameters of the Na+/H+ antiport in human fibroblasts and platelets.

A technique is presented to estimate the initial rates of Na(+)-dependent alkalinization of acidified human fibroblasts and platelets and assess the kinetics of the Na+/H+ antiport in these cells. Cytosolic pH (pHi) exhibits an exponential recovery following cellular acidification. Thus, the length of the time interval selected to monitor changes in pHi (delta pHi) is critical to estimating the kinetics of the Na+/H+ antiport. We compared kinetic parameters of the Na+/H+ antiport, using computed and observed changes in delta pHi, for arbitrarily selected time intervals following Na(+)-dependent activation. In both cells, significant increases in both the [Na+] for half-maximal activation (K0.5) and maximal velocities (Vmax) were observed as delta pHi was decreased. We conclude that kinetic parameters derived from initial rate determinations enable a more accurate characterization of the Na+/H+ antiport.

Biological Transport, Active↗
PubMed1990

Acute gastroenteritis due to double infection with enteropathogenic Escherichia coli or Salmonella and another bacterial pathogen.

Two enteric bacterial pathogens were concomitantly isolated from the feces of 18 infants less than 6 months of age admitted to the Assaf Harofeh Medical Center over a 7-year period. In all but two patients stool cultures grew enteropathogenic Escherichia coli, six of serogroup 0119. The other organisms cultured were Shigella, Salmonella, Campylobacter jejuni and Aeromonas hydrophila. The usual clinical presentation was diarrhea, dehydration and vomiting of acute onset, and low grade fever. Patients with gastroenteritis due to a single agent compared with multiple pathogens had a milder course of disease, a milder degree of dehydration and acidosis, a lesser need for i.v. fluid treatment and shorter hospitalization.

Academic Medical Centers↗
PubMed1989

Elevated serum creatine kinase. Following febrile seizures.

Serum creatine kinase (CK) was determined in 52 children admitted following an episode of febrile convulsions. Enzyme levels correlated with the estimated duration of the seizure. Twenty-four hour values were significantly higher than those observed 1 hour after the convulsive episode. Serum CK levels are frequently used for diagnostic purposes, so the questionable validity of this test when drawn after a convulsive episode must be considered.

Age Factors↗
PubMed1989

The effect of oral calcium load or verapamil on gentamicin-induced nephrotoxicity.

Several investigators have reported recently that in rats, oral calcium load is associated with a marked amelioration in gentamicin-induced renal failure. In contrast to these reports, using the same animal model, we could not observe calcium-induced moderation in gentamicin nephrotoxicity as reflected by either urea or creatinine serum concentration or by various renal cortical intracellular enzymatic activities. Similarly, verapamil, a calcium channel blocker, had no effect on the degree of renal failure in these animals. We conclude that manipulation of calcium diet may not be uniformly effective in reducing gentamicin nephrotoxicity. Additional nutritional factors may play a crucial role in achieving the amelioration of this model of toxic nephropathy.

Acute Kidney Injury↗
PubMed1988

Cyclophosphamide in treatment of minimal change nephrotic syndrome.

Nineteen children with the minimal change form of nephrotic syndrome were divided according to their pattern of response to prednisone: steroid-dependent and frequent relapsers. All patients received cyclophosphamide for 56 days in a single daily dose of 2.5 mg/kg (total 140 mg/kg), in order to prolong the length of remission. The percentage of patients who continued in remission at the end of the 1st, 2nd and 5th years was greater in the frequent-relapser group. This retrospective analysis confirms that the pattern of response to prednisone may be an important criterion for the selection of patients who will benefit from cyclophosphamide therapy.

Adolescent↗
PubMed1988

Heredofamilial syndrome of mesodermal hamartomas, macrocephaly, and pseudopapilledema.

A 4 1/2-year-old boy with macrocephaly, pseudopapilledema, lipoangiomatosis, macropenia, and spotted pigmentations of the glans is reported. Lipoid masses were found in the subcutaneous tissue, tonsils, and probably the left lung. Some of these findings are consistent with features already reported by Riley and Smith, later by Bannayan, and recently by Ruvalcaba et al. We propose to unify the features of this syndrome and name it macrocephaly, hamartomas, and papilledema syndrome. The inheritance in our described case seems to be autosomal dominant.

Child, Preschool↗