Search PubMed⌕ Search

Biomedical subjects

S Edelstein

Publications and source records attributed to S Edelstein.

At least 37 records · Page 2Linked to original sources
PubMed1995

Low plasma cholesterol predicts an increased risk of lung cancer in elderly women.

BACKGROUND: There have been significant efforts in the United States to lower high cholesterol levels. Studies of men, however, have found a higher total cancer mortality rate at lower levels of plasma cholesterol. Many of these studies have found that lung cancer is more closely associated than other cancers with low cholesterol. Of the studies that include women, none has demonstrated a statistically significant inverse association between low cholesterol and lung cancer. METHODS: We examined the relation between very low plasma cholesterol levels ( < 160 mg/dl) and lung cancer death in an 18-year prospective study of 2,011 men and 2,327 women. RESULTS: After adjusting for age, body mass index, smoking, and education, the relative hazard of lung cancer mortality for those with low cholesterol ( < 160 mg/dl) compared with all other cholesterol levels ( > or = 160 mg/dl) was 1.75 among men (P = 0.28) and 3.29 among women (P = 0.02). Excluding those who died within 5 years of baseline did not change the results. CONCLUSIONS: Both men and women with baseline plasma cholesterol levels < 160 mg/dl were more likely to die of lung cancer. This difference was statistically significant in women. The association could not be explained by occult malignancy, smoking, or socioeconomic status.

Adult↗
PubMed1995

[The audiometric evaluation of Buenos Aires schoolchildren].

This cross-sectional study, which was carried out between 3 May and 30 September 1993, involved examination with a pediatric otoscope of a random sample of 100 first-grade schoolchildren in a Buenos Aires hospital, followed by tonal audiometry and tonal sweep in 90 of those children. The objectives of the study were to discover the frequency of hearing disorders and to evaluate the importance of audiometric screening in the child population. The results were classified according to the type (conduction or perception) and degree (mild, moderate, or severe) of hypoacusis, which was detected in 36 children (39%). Of those affected, 35 had mild or moderate conduction hypoacusis (loss of less than 31 decibels [dB] or less than 41 dB, respectively). No case of severe hypoacusis was found. The authors consider that audiometric screening of children entering primary school is justified by the high frequency of preventable hearing problems and by the repercussions that those problems can have on speech and learning.

Argentina↗
PubMed1994

Vitamin D metabolites and extracellular calcium regulate calcium currents in hemocytes of land snails.

Intracellular exchangeable calcium and calcium efflux were investigated in cultured amoebocytes of land snails. Low extracellular calcium concentration (0.32 mM) initiated a rapid increase of outward calcium currents and decrease of intracellular exchangeable calcium. On the other hand, high extracellular calcium concentration (32 mM) increased intracellular exchangeable calcium. Actions of vitamin D metabolites were most prominent under non-physiological concentrations of extracellular calcium. Metabolite E activated a calcium pump while 25-hydroxy-vitamin D3 deactivated the pump. Both metabolites increased calcium transfer into stored pools.

Animals↗
PubMed1994

24,25-Dihydroxyvitamin D3 antagonizes some of the actions of 1,25-dihydroxyvitamin D3.

The effect of 24,25-dihydroxyvitamin D3 on some of the activities of 1,25-dihydroxyvitamin D3 was studied in cultures of cartilage cells obtained from the tibial growth plate of rachitic chicks. The activities that were tested are those associated with intracellular exchangeable calcium, alkaline-phosphatase activity and the incorporation of thymidine and proline. 24,25-dihydroxyvitamin D3 was shown in this system to antagonize the suppressive effect of 1,25-dihydroxyvitamin D3 on intracellular exchangeable calcium and on proline incorporation. A similar effect on alkaline phosphatase activity and thymidine incorporation was not observed.

24,25-Dihydroxyvitamin D 3↗
PubMed1994

The association between health beliefs and health behavior change in older adults.

BACKGROUND: Previous studies have reported weak relationships between health beliefs and behavior change; few studied elderly populations. METHODS: We examined the relation between self-reported behavior change and health-related beliefs among an educated, upper-middle-class population age 50 to 89 years. RESULTS: More women reported decreasing dietary salt and fat, changing diet, and reading self-help materials than men. Younger respondents (age 50 to 69 years) reported more positive health behavior changes in diet and exercise than did older respondents (age 70 to 89 years). Respondents who agreed that diet and exercise were important for optimal health and/or spent money on healthful items reported more positive behavior change than those who disagreed. Those who reported confusion about how to stay healthy or a lack of motivation to engage in healthful behaviors were less likely to make positive lifestyle changes. Older respondents reported a higher rate of confusion regarding which foods to eat (53% vs 39%) and how to stay healthy (29% vs 19%) than younger respondents, while younger respondents were more likely to report a problem with motivation (40% vs 34%). CONCLUSIONS: These results suggest that increasing age does not diminish the relation between health beliefs and health behaviors. Health promotion campaigns aimed at older adults should strive to reduce confusion to improve health behavior.

Age Factors↗
PubMed1994

Calcium cells from snails: response to vitamin D metabolites.

Calcium is one of the most important substances affecting the life of molluscs, and vitamin D was shown to be an essential nutrient for land snails. In an attempt to elucidate the role that vitamin D plays in calcium metabolism of land snails, we have developed a procedure for the isolation of specialized calcium cells from digestive gland of land snails, and were able to culture these cells. The effect of vitamin D metabolites on the intracellular exchangeable calcium and alkaline phosphatase activity was studied. The metabolites tested were 25-hydroxycholecalciferol (25(OH)D3), 24,25-dihydroxycholecalciferol (24,25(OH)2D3), 1,25-dihydroxycholecalciferol (1,25(OH)2D3), and the molluscan metabolite E. 25(OH)D3 was found to be the most active sterol in elevating intracellular exchangeable calcium and the activity of alkaline phosphatase, and the molluscan metabolite E was found to be the most potent sterol in the suppression of alkaline phosphatase activity. 1,25(OH)2D3 was shown to suppress both activities at high concentrations, and 24,25(OH)2D3 increased the intracellular exchangeable calcium only at high concentrations. Thus, 25(OH)D3 which is regarded as a storage form of vitamin D and devoid of biological activity, seems to be biologically active in invertebrates.

24,25-Dihydroxyvitamin D 3↗
PubMed1994

Dietary sodium and bone mineral density: results of a 16-year follow-up study.

BACKGROUND AND PURPOSE: It has been proposed that high dietary sodium intake, resulting in a sodium-mediated increase in renal calcium excretion, is a risk factor for osteoporosis. To evaluate the relationship between dietary sodium intake and bone mineral density (BMD), a prospective study of the Rancho Bernardo cohort was performed. METHOD: A 24-hour diet recall was done for the period 1973 through 1975; follow-up bone mineral density of the ultradistal radius, midradius, total hip, and spine was measured between 1988 and 1991. Covariates were ascertained by self-report and examination at baseline. Multivariable analysis of the sodium-BMD association was performed using gender and menopause-specific linear regressions. RESULTS: All subjects were white. At the bone evaluation, there were 258 women (average age 73.3 years) and 169 men (average age 72.4 years). In both men and women, higher levels of sodium intake were strongly associated with higher levels of calcium intake and total calories. Body mass index increased with sodium quartile in women, while a modest negative association was seen in men. In women, after age adjustment, positive associations between dietary sodium and bone density were found at the ultradistal radius (beta = 0.01, P = 0.03) and the total hip (beta = 0.019, P = 0.02). BMD increased by 0.01 to 0.02 g/cm2 per gram increase in sodium ingested. After adjustment for estrogen use, body mass, dietary calcium, alcohol, and total calories, these effects were no longer significant. Similar patterns were seen in pre- and postmenopausal women. In men, age and multivariate-adjusted BMD increased with higher sodium intake at the ultradistal radius only (beta = 0.013, P = 0.05). Stratification by gender-specific median calcium level did not significantly effect the results. CONCLUSIONS: After control for confounders, a small, statistically significant protective effect of sodium was found at the ultradistal radius in men only. At other sites in women and men, no effect of sodium on BMD was apparent in the multivariable models. These results do not support a detrimental effect of dietary sodium on bone mineral density. Rather, the findings suggest that sodium intake, in the range measured, is not a major osteoporosis risk factor.

Aged↗
PubMed1994

Lifetime milk consumption and bone mineral density in older women.

This study examined the relationship between lifetime milk consumption both axial and appendicular bone mineral density in 581 postmenopausal White women. Positive significant, graded associations between milk consumption in adulthood and bone mineral density at the spine, total hip, trochanter, intertrochanter, and midradius, but not the ultradistal wrist or femoral neck, were observed. Adolescent milk consumption showed similar, statistically significant associations (spine and midradius). Associations were independent of age, body mass index, years postmenopausal, thiazide, estrogen and alcohol use, smoking, and exercise. Regular milk consumption in youth and adulthood is associated with better bone mineral density at cortical and trabecular sites in elderly women.

Adolescent↗
PubMed1993

The effect of vitamin D3 deficiency on the isolated chick heart: hemodynamic, P-31 NMR and membrane studies.

The purpose of this study was to investigate whether vitamin D3 deficiency affects the cardiac function of chick hearts directly or whether the influence is secondary through the hormone's effect on serum calcium levels. To this end, three experimental groups were studied: (a) the control group of vitamin D3 supplemented chicks, Ds, (b) vitamin D3 deficient chicks, Dd, and (c) vitamin D3 supplemented hypocalcemic chicks raised on decreased calcium levels, Dh. The three groups were compared by checking hemodynamic, metabolic and membrane parameters. Total and ionized serum calcium concentrations in the Dh and Dd groups were found to be lower than in the Ds group. Perfusion of the isolated hearts with solutions containing various calcium concentrations (1, 1.5 and 2.5 mM) induced enhanced contractility levels, the magnitude of which was dependent on the difference between the in vivo and perfusate calcium levels. Thus, the inotropic effect was similar and more enhanced for the two hypocalcemic groups. The differences in hemodynamic behaviour could not be explained by variations in the levels of the high energy compounds and acidity, since similar ATP, creatine phosphate and intracellular pH levels were detected for both Ds and Dd groups. However, membrane studies revealed an increase in the number of slow calcium channels for the two hypocalcemic groups and this may be the possible mechanism for the differences in the contractile activity. In conclusion, our study strongly suggests that the effects of vitamin D3 on the heart is mediated only indirectly through its effect on serum calcium levels.

Animals↗
PubMed1993

Decrease in bone levels of 1,25-dihydroxyvitamin D in women with subcapital fracture of the femur.

In a previous study we were able to show that in women over the age of 45 the level of 1,25-dihydroxyvitamin D (1,25(OH)2D) in bone, but not in serum, is significantly reduced when compared with younger women. In the present study we measured the concentration of 1,25(OH)2D in sera and bones of 19 female patients with subcapital fractures of the femur, mean age 78 +/- 2 years. We were able to show that serum levels of 1,25(OH)2D were within the normal range, while bone levels were markedly reduced compared to levels in femoral bone obtained from young female cadavers or to the previously reported levels in non-osteoporotic elderly women. Thus, reduced levels of 1,25(OH)2D in bones of elderly women may lead, together with other factors, to subcapital fractures.

Adult↗
PubMed1993

External cephalic version at term--using tocolysis.

Fifty-five patients with non-vertex presentation at 37 to 40 weeks' gestation were evaluated to determine which factors were associated with a successful external cephalic version (ECV). Maternal parity, obesity, amniotic fluid volume, placental location, type of breech and position of fetal spine were analyzed. Only amniotic fluid volume and fetal weight were significantly associated with a successful version (p < 0.05), 40/55 (73%) were successfully converted, 36/55 (65%) were vertex at delivery, and 32/55 (58%) delivered vaginally. Version attempts were successful in six out of eight patients who had undergone a previous cesarean section. Two out of six of the successful version patients went on to have vaginal birth after cesarean section. We conclude that although ECV is a reasonable alternative in the management of pathological presentation near term it should be performed only when there is sufficient amniotic fluid volume.

Breech Presentation↗
PubMed1993

Cigarette smoking and preeclampsia.

OBJECTIVE: To examine the relationship between cigarette smoking during pregnancy and the development of preeclampsia. METHODS: A case-control study compared the smoking histories of 110 nulliparous preeclamptic women and 115 healthy nulliparas aged 15-35 years who delivered at North Carolina Memorial Hospital. RESULTS: Unconditioned logistic regression relating smoking during pregnancy to preeclampsia yielded an odds ratio of 0.71 (95% confidence interval 0.33-1.50) when adjusting for working during pregnancy, alcohol use, medication use, contraceptive choices with the father of the index pregnancy, and family history of preeclampsia. There was no evidence of a dose-response effect of reduced risk for heavier smokers. CONCLUSIONS: Despite major methodologic improvements from previous studies, including rigorous diagnostic criteria for preeclampsia, a negative, non-statistically significant association persisted between cigarette smoking during pregnancy and preeclampsia, similar in magnitude to that of previous reports.

Adolescent↗
PubMed1992

Decrease in bone level of 1,25-dihydroxyvitamin D in women over 45 years old.

The most active metabolite of vitamin D is 1,25-dihydroxyvitamin D [1,25(OH)2D]. Its level in the bone may play a role in the pathogenesis of metabolic bone diseases such as osteoporosis. To assess this, and to see whether there is correlation between serum and bone levels, we studied serum and bone samples taken from 43 patients (18 men and 25 women) undergoing different orthopedic procedures. Patients were studied according to sex and age groups (less than 45 years, 46-60 years, greater than 61 years). Serum level of 1,25(OH)2D was found to be 29.7 +/- 2.61 pg/ml (mean +/- SEM) for women, 32.2 +/- 3.86 pg/ml for men, and 30.7 +/- 2.18 pg/ml for the group as a whole. No significant statistical differences were found among age subgroups in either sex or between sexes. Bone level of 1,25(OH)2D was found to be 31.5 +/- 4.46 pg/g for women, 26.5 +/- 3.06 pg/g for men, and 29.4 +/- 2.81 pg/g for the entire group. No significant statistical difference was found between the age subgroups for men. However, the level of 1,25(OH)2D was found to be higher in the group of younger women (less than 45 years) compared with the older women (46-60 years and greater than 61 years) (P less than 0.005).

Adolescent↗
PubMed1992

Structural modeling of the human erythrocyte bisphosphoglycerate mutase.

Using the crystallographic structure of yeast monophosphoglycerate mutase (MPGM) as a framework we constructed a three-dimensional model of the homologous human erythrocyte bisphosphoglycerate mutase (BPGM). The modeling procedure consisted of substituting 117 amino acid residues and positioning 19 C-terminal residues (unresolved in the X-ray structure) by empirical methods, followed by energy minimization. Among several differences in the active site region the most significant appears to be the replacement of Ser11 in MPGM by Gly in BPGM. The C-terminal segment, which contains mainly basic amino acids, lines the cavity of the active site. The seven amino acid residues, which have been shown to be essential for the three catalytic functions of the human BPGM, interact with the amino acids in the protein core, near the active site. In addition, a cluster of several positively charged residues, particularly arginines, has been identified at the entrance of the active site; this cluster may serve as a secondary binding site for polyanionic substrates or cofactors, as required by a two-binding-site model of the catalytic activities. This model is in agreement with recent studies of an inactive BPGM variant substituent at an Arg position situated in this positively charged cluster. The position of Cys20 in the model constructed suggests that this residue is responsible for inactivation of the enzyme by sulfhydryl reagents. Subunit interfaces have also been constructed for BPGM by analogy with MPGM and suggest that, in addition to the known dimerization of BPGM, tetramerization may occur under certain conditions.

Amino Acid Sequence↗
PubMed1991

Oral administration of 24,25(OH)2D3 suppresses the serum parathyroid hormone levels of dialysis patients.

We measured the serum parathyroid hormone (PTH) levels in 20 patients treated with continuous ambulatory peritoneal dialysis before and after oral treatment with 24,25-dihydroxyvitamin D3- 24,25(OH)2D3. This metabolite was given in addition to existing treatment with 1 alpha-OH-D3 and calcium carbonate. Administration of 24,25(OH)2D3 led to a significant decrease in PTH levels (intact molecule) from 382 +/- (SE) 65 to 245 +/- 54 pg/ml in 9 patients whose initial levels were extremely high (p = 0.01). No side effects were observed. On the average, calcium values were unchanged and within the normal range throughout the study period; however, a few episodes of mild asymptomatic hypercalcemia occurred which responded quickly to reduction of the calcium carbonate dosage. The present study suggests that oral administration of 24,25(OH)2D3 combined with 1 alpha-OH-D3 is safe and capable of suppressing the raised serum PTH levels of end-stage renal disease patients without the danger of significant hypercalcemia.

24,25-Dihydroxyvitamin D 3↗
PubMed1991

Relation between leisure-time physical activity and blood pressure in older women.

Although there is some evidence that physical activity may decrease blood pressure in young and middle-aged women, the physical activity-blood pressure association in older women has rarely been studied. As part of an ongoing community-based study of chronic disease, 641 Caucasian women between the ages of 50 and 89 years had blood pressure measured following the Hypertension Detection and Follow-up Program protocol. They also answered selected Health Interview Survey questions about their leisure-time activity and were classified into categories of light (58%), moderate (24%), heavy (6%), or no physical activity (12%) by the estimated metabolic rate required for each activity. Women who engaged in any physical activity were significantly younger and thinner than sedentary women and had lower fasting and 2-hour postchallenge insulin levels. They did not differ in alcohol consumption, cigarette use, or prevalence of coronary heart disease or diabetes. Rates of systolic and diastolic hypertension were significantly lower in women participating in light, moderate, or heavy physical activity compared with sedentary women. Blood pressure levels decreased with each increase in reported activity intensity (p less than 0.005 for trend), with systolic blood pressure approximately 20 mm Hg lower in the heaviest activity group compared with systolic blood pressure in sedentary women. Intergroup differences remained statistically significant after adjustment for age and body mass index. Although physical activity was associated with lower fasting and 2-hour postchallenge insulin levels (p less than 0.01 for trend), adjustment for insulin levels did not alter blood pressure differences among activity groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗