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Biomedical subjects

S Levin

Publications and source records attributed to S Levin.

At least 559 records · Page 31Linked to original sources
PubMedDate not supplied

Effect of intensive glycemic control on fibrinogen, lipids, and lipoproteins: Veterans Affairs Cooperative Study in Type II Diabetes Mellitus.

BACKGROUND: The Veterans Affairs Cooperative Study in Type II Diabetes Mellitus prospectively studied insulin-treated patients with type 2 (non-insulin-dependent) diabetes mellitus, achieving 2.1% glycosylated hemoglobin separation between intensive- and standard-treatment arms (P<.001) for 2 years. OBJECTIVE: To assess the effect of intensive therapy on serum fibrinogen and lipid levels, compared with standard treatment. METHODS: One hundred fifty-three male subjects with type 2 diabetes mellitus and who required insulin treatment were recruited from 5 Veterans Affairs medical centers. The subjects were divided into intensive- and standard-treatment arms for a randomized prospective study. Dyslipidemia was managed identically in both arms (diet, drugs). Fibrinogen levels and lipid fractions were measured in the full cohort. Lipid fractions are separately reported in patients not treated with hypolipidemic agents. RESULTS: There were no baseline differences between arms. Fibrinogen levels rose in the intensive-treatment arm at 1 year (from 3.34+/-0.12 to 3.75+/-0.15 g/L; P<.001) but returned to baseline at 2 years (3.47+/-0.12 g/L). There was no change in the standard-treatment arm. Triglyceride levels decreased in the intensive-treatment arm from 2.25+/-0.27 to 1.54+/-0.14 mmol/L (199+/-24 to 136+/-12 mg/ dL) at 1 year (P = .004) and to 1.74+/-0.18 mmol/L (154+/-16 mg/dL) at 2 years (P = .03); there was no change in the standard-treatment arm. Cholesterol levels decreased in the intensive-treatment arm at 1 year from 5.4+/-0.21 to 4.99+/-0.13 mmol/L (207+/-8 to 193+/-5 mg/dL) (P = .02); there was no change in the standard-treatment arm. Levels of low- and high-density lipoprotein cholesterol decreased in the standard-treatment arm only by 2 years, from 3.44+/-0.13 to 3.16+/-0.10 mmol/L (133+/-5 to 122+/-4 mg/ dL) (P =.02) and from 1.10+/-0.03 to 1.00+/-0.03 mmol/L (42+/-1 to 38+/-1 mg/dL) (P<.001) for low-density and high-density lipoprotein cholesterol, respectively. Levels of apolipoprotein B decreased in both treatment arms (P<.001), and apolipoprotein A1 levels decreased in the standard-treatment arm (P<.01). Lipoprotein (a) levels did not change in either treatment arm. Lipid results were essentially identical whether examined in the full cohort or excluding those patients receiving hypolipidemic agents. CONCLUSIONS: Intensive insulin therapy led to a potentially beneficial reduction in serum triglyceride levels and preservation of high-density lipoprotein cholesterol and apolipoprotein A1 levels. However, it caused transient elevation in plasma fibrinogen levels, a possible thrombogenic effect.

Adult↗
PubMedDate not supplied

Insulin secretion, obesity, and potential behavioral influences: results from the Insulin Resistance Atherosclerosis Study (IRAS).

BACKGROUND: This work was conducted to evaluate associations of insulin secretion with overall and central obesity, dietary fats, physical activity, and alcohol. METHODS: A frequently sampled intravenous glucose tolerance test (FSIGT) was used to assess acute insulin response to glucose (AIR) and insulin sensitivity (S(I)) among adult participants (n=675 with normal, NGT; n=332 with impaired glucose tolerance, IGT) in the Insulin Resistance Atherosclerosis Study (IRAS). Disposition index (DI) was calculated as the sum of the log-transformed AIR and S(I) to reflect pancreatic compensation for insulin resistance. Obesity was measured as body mass index (kg/m(2), BMI) and central fat distribution by waist circumference (cm). Dietary fat intake (total, saturated, polyunsaturated, oleic acid), physical activity, and alcohol intake were assessed by standardized interview. RESULTS: In unadjusted analyses, BMI and waist were each positively correlated with AIR among NGTs (r=0.26 and 0.23, respectively; p<0.0001) but correlations were weaker among the IGTs (r=0.10, NS; r=0.13, p<0.05 for BMI and waist, respectively). BMI and waist were inversely correlated with DI among NGTs (r=-0.13 and -0.20, respectively; p<0.0001) and among IGTs (r=-0.20 and -0.19, respectively, p<0.0001). Dietary fat variables were positively related, and alcohol was inversely related, to AIR among NGTs (p<0.01) but not among IGTs. With all factors considered simultaneously in a pooled analysis of IGTs and NGTs, waist, but not BMI, was positively associated with AIR (p<0.001) and inversely associated with DI (p<0.01). None of the behavioral variables were independently related to either outcome. CONCLUSION: Among non-diabetic patients, central obesity appears to be related to higher insulin secretion, but to lower capacity of the pancreas to respond to the ambient insulin resistance.

Adult↗
PubMedDate not supplied

The relation between Apgar score and subsequent developmental functioning.

A randomly selected sample of 252 infants aged 5--18 months was evaluated through medical and developmental examinations. Developmental achievement scores and factors such as management of delivery and fetal distress were studied in relation to Apgar scores. Low-Apgar-score infants aged 5--8 months achieved consistently lower scores on all developmental fields. High-Apgar-score infants at younger and older ages did not differ on their achievement scores. Low Apgar score was much more frequent in infants delivered by vacuum extraction than in those delivered spontaneously, with forceps or by cesarian section. The frequency of low Apgar score was higher when fetal distress occurred.

Apgar Score↗
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Significance of mirex-caused hypoglycemia and hyperlipidemia in rats.

Treatment of rats with mirex (40 ppm in diet) caused hypoglycemia, liver enlargement, and inhibition of adrenal corticosteroid-synthesizing enzyme activity. At toxic dosages (20,000 ppm mirex in diet, which has a lethal toxicity-50 [LT-50] of ten days) poisoned female rats showed severe hypoglycemia, fatty liver, adrenal hyperplasia, hypophagia, lipid mobilization, and body weight (bw) loss. A 50 micrograms/kg intraperitoneal (IP) dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in male rats caused similar effects two days posttreatment. Hypoglycemia could be overcome by prednisone (which also inhibited adrenocorticoid-synthesizing enzyme activities) but not by streptozotocin treatment, indicating that hypoglycemia may be related to glucocorticoid deficiency resulting from inhibition of their synthesis and not by direct effects on pancreatic beta-cells. Glucocorticoid deficiency could also cause increased release of adrenocorticoid hormone (ACTH), which may enhance fat mobilization caused by hypophagia.

Adrenal Glands↗
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Influence of glucose fluctuations on alkaline phosphatase activity.

It has been suggested previously that non-enzymatic glycosylation of certain enzymes results in decreased enzymatic activity. In order to examine the role of high blood glucose concentrations (BG) on serum alkaline phosphatase (AP) activity, we determined BG and serum AP in 32 healthy children during an oral glucose tolerance test (OGTT) and in 10 type I diabetic children at 30-min intervals for at least 150 min. A significant negative correlation was noted for BG and AP during the oral glucose load (r = -0.57, p less than 0.01). In diabetics, however, only children with marked BG fluctuations showed this inverse relationship between BG and AP. These observations could be explained by the formation of a Schiff base as the initial step of non-enzymatic glycosylation of AP. This assumption was further confirmed by in vitro experiments, in which AP was incubated with glucose resulting in decreased enzymatic activity. The dialyzable aldimine formed initially is subsequently stabilized as ketoamine after long-term incubation.

Adolescent↗
PubMedDate not supplied

The effects of population heterogeneity on disease invasion.

The incorporation of population heterogeneity is a central issue in theoretical biology, and it has received considerable attention in epidemiology recently. This paper presents general conclusions and interpretations about the effects of heterogeneity, with and without positive assortative mating, on the ability of a disease to establish itself. We show that the invasion of a disease into a population with random mixing is determined by an average of reproductive numbers for each subgroup, weighted by the total amount of mixing activity of the subgroup. In particular, if the mixing rate is constant across the population, invasion occurs if and only if the average reproductive number for the population exceeds 1. In the case of "preferred mixing," one can find a critical number for each subgroup such that invasion occurs if and only if a suitably defined average over subgroups exceeds 1.

Epidemiologic Methods↗
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Transmyocardial laser revascularization: current status.

Transmyocardial laser revascularization (TMLR) has been widely evaluated for treatment of the ischemic myocardium either in conjunction with coronary artery bypass grafting or as sole therapy. Clinically, it has shown significant improvement for angina symptoms, but the mechanism by which this modality works is unknown at this time. The original premise on which transmyocardial revascularization was established depended on its ability to essentially generate channels that would directly carry blood from the ventricle into the ischemic myocardium. This theory, however, has not been substantiated, so other mechanisms have been postulated. This article gives a historical perspective on the advent of transmyocardial revascularization and the many animal and human studies that have paved the way for its clinical use. Current controversies are examined, along with the new advances in laser technology and where the future of TMLR is headed.

Animals↗
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Community-acquired purulent meningitis: a review of 1,316 cases during the antibiotic era, 1954-1976.

This review of 1,316 cases of purulent meningitis assessed changes in the etiology, clinical features, and fatality rate during the antibiotic era. Hemophilus influenzae was the most frequent cause of purulent meningitis (458 cases), Neisseria meningitidis the second most frequent (396 cases), and Streptococcus pneumoniae the third most frequent (178 cases). No bacterial etiology was found for 148 patients with purulent meningitis, the fourth major category of meningitis throughout the 23 years surveyed. Few patients had notable underlying diseases or predisposing conditions; 77.4% were less than 10 years old, but only 13 patients were less than one month old. Patients with meningitis caused by Staphylococcus aureus or various streptococci commonly had associated suppurative foci and the highest fatality rate. There were 103 deaths, of which 70.8% occurred during the first 48 hr of hospitalization. Antibiotics had been given to 54.6% of patients before admission to the hospital. Bacteriologic and cerebrospinal fluid (CSF) findings for patients who received antibiotics prior to admission ("pretreated") were compared with these findings for those who had not had antibiotics in 1,032 cases of meningitis caused by H. influenzae, N. meningitidis, or S. pneumoniae. No significant differences in white blood cell counts or in glucose or protein concentrations in CSF were noted among patients infected with any of the three organisms; positive cultures of blood and CSF were significantly less frequent in "pretreated" patients whose disease was caused by any of the three organisms, and particularly in those with meningitis due to N. meningitidis. Nasopharyngeal, throat, and rectal swabs and CSF specimens from 141 patients were cultured for virus. Enteroviruses were isolated from rectal swabs of two patients with bacterial meningitis and from the CSF of two patients (in mixed culture with Salmonella enteritidis in one case).

Adolescent↗
PubMedDate not supplied

Herpes simplex viral hepatitis in adults: two case reports and review of the literature.

Herpes simplex viral (HSV) hepatitis is uncommon in adults. Two new cases are reported herein; a literature review revealed an additional 33 patients. Ages ranged from 13 to 87 years; the mean age was 32.6 years, and the median was 28 years. HSV hepatitis usually occurs as part of disseminated HSV infection and is characterized by fulminant hepatic necrosis with serum transaminase levels frequently elevated 100- to 1,000-fold. Disseminated intravascular coagulation was present in 90% of the cases. Outcome was poor; 86% of the patients died. Eighty-six percent of the patients had an underlying condition associated with impaired host defenses. Renal transplantation (26%), steroid use other than in renal transplant patients (26%), and pregnancy (23%) were the most frequent underlying conditions. Early recognition and prompt initiation of antiviral therapy may offer a chance for improved survival rates.

Adult↗
PubMedDate not supplied

Gentamicin- and clindamycin-resistant Staphylococcus aureus.

From 1975 through 1978 isolates from 21 of 230 (9%) Staphylococcus aureus bacteremias were resistant to gentamicin and clindamycin. Gentamicin- and clindamycin-resistant S aureus (GCRS) accounted for 23% of all S aureus isolates from 1977 compared with 2 to 6% in the two years immediately preceding, and the year following 1977. When compared with patients with gentamicin- and clindamycin-sensitive S aureus (GCSS) from 1977, GCRS were more often isolated from patients who acquired their infections in the hospital, particularly in the intensive care unit. A significant association existed between prior or concurrent therapy with gentamicin and/or clindamycin and the isolation of GCRS. Infection with GCRS was associated with a 73% mortality rate versus 28% with GCSS. GCRS were susceptible to oxacillin, cephalothin, tetracycline, and vancomycin. GCRS were resistant to kanamycin and tobramycin but were susceptible to amikacin (median MIC of GCRS, 4.0 microgram/ml). Multiple bacteriophage types of S aureus were involved, and resistance appeared to be plasmid-mediated. A survey of antibiotic usage showed that in comparison to January 1977, a mikacin usage increased and gentamicin usage decreased in March 1979. Because of the popularity of the combination of clindamycin and gentamicin for therapy of life-threatening infections, clinicians should be aware of potential gentamicin- and clindamycin-resistance in S aureus.

Clindamycin↗
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Neonatal neurofibromatosis: unusual manifestations with malignant clinical course.

A family with neurofibromatosis is reported in which the proband was an infant in whom the diagnosis was established at birth. In this case, the presenting symptom was a large tumor of the tongue and macrocephaly. Cafe-au-lait spots appeared early, as did additional subcutaneous tumors, with skeletal involvement and severe psychomotor retardation. The rapid growth of the tumor, its spread within the mediastinum, neck and oral cavity, led to a strangulating death at one year of age. The disease originates from early embryonic involvement of the neural crest and from tissues derived from its caudal end. It is probably caused by a single pleiotropic gene transmitted as an autosomal dominant trait, with varying expression of the disease in different members of the same family.

Adolescent↗
PubMedDate not supplied

Reifenstein's syndrome--a target cell failure.

The features of Reifenstein's Syndrome comprise hypospadias, microtestes, gynecomastia, azoospermia and elevated gonadotropins. The disease is inherited as either a male limited autosomal dominant or as a X-linked recessive trait and affects only genetic males. A case is reported suffering from this condition. Pituitary function was evaluated using the GnRH-test and appeared to be normal. Prolactin and testosterone values were in the normal range. The patient was a phenotype male and sexual function was satisfactory. Primary tubular failure resulting in hypergonadotropic hypogonadism was diagnosed. No other relatives were found to be affected. The syndrome seems to be due to relative insensitivity of Leydig cells to androgens.

Adult↗
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Enamel solubility rate measurements in vivo on naval recruits.

Enamel solubility rates were determined in vivo to depths of 1 to 2 mum in the teeth from two samples of naval recruits that had been grouped, respectively, according to DMFT scores and visual indexes of oral hygiene status. No positive correlation between enamel solubility rates and DMFT scores were observed; rather there was a tendency for caries-resistant participants to have a highest apparent enamel solubility rates, even though mean differences among the DMFT groups were not generally significant. Intra-subject measurements on 12 teeth per participant for eight of the recruits showed, on the average, only about one half the variability founl incisors for more than 70 of the recruits. The least variability was found for measurements on paired maxillary central incisors. It was concluded that factors such as tooth morphology and, in particular, tooth-surface films could considerably affect enamel solubility rates measured in vivo.

Adolescent↗