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Biomedical subjects

S Weiss

Publications and source records attributed to S Weiss.

At least 163 records · Page 9Linked to original sources
PubMed1998

A randomized trial of the effects of atorvastatin and niacin in patients with combined hyperlipidemia or isolated hypertriglyceridemia. Collaborative Atorvastatin Study Group.

BACKGROUND: To assess the lipid-lowering effects and safety of atorvastatin and niacin in patients with combined hyperlipidemia or isolated hypertriglyceridemia. METHODS: We performed a randomized, open-label, parallel-design, active-controlled, study in eight centers in the United States. We enrolled 108 patients with total cholesterol (TC) of > or =200 mg/dL, serum triglycerides (TG) > or =200 and < or =800 mg/dL, and apolipoprotein B (apo B) > or =110 mg/dL. Patients were randomly assigned to receive atorvastatin 10 mg once daily (n=55) or immediate-release niacin 1 g three times daily for 12 weeks (n=53). Patients were stratified based on low-density lipoprotein cholesterol (LDL-C): Patients with LDL-C > or =135 mg/dL were considered to have combined hyperlipidemia and patients with LDL-C <135 mg/dL were considered to have isolated hypertriglyceridemia. The primary outcome measure was percent change from baseline in LDL-C. Other lipid levels were evaluated as secondary parameters. RESULTS: Atorvastatin reduced LDL-C 30% and TC 26% from baseline, and increased high-density lipoprotein cholesterol (HDL-C) 4%. Total TG were reduced 17%. Niacin reduced LDL-C 2%, TC 7%, increased HDL-C 25%, and reduced total TG 29% from baseline. There was a significant difference in LDL-C reduction, the primary efficacy parameter, between the two treatment groups (P <0.05, favoring atorvastatin), as well as a significant difference in the improvement in HDL-C (P <0.05, favoring niacin). The effect of atorvastatin was relatively consistent between patients with combined hyperlipidemia and isolated hypertriglyceridemia, whereas there was more variability between these strata in the niacin treatment group. Atorvastatin was better tolerated than niacin. CONCLUSION: Atorvastatin may allow patients with combined hyperlipidemia to be treated with monotherapy and offers an efficacious and well-tolerated alternative to niacin for the treatment of patients with isolated hypertriglyceridemia.

Adult↗
PubMed1998

Near-field fluorescence microscopy of cells.

We demonstrate the surface sensitivity of near-field scanning optical microscopy by fluorescence imaging of membrane and bulk proteins in cells. We discuss instrument design considerations for successful cell-biology work with NSOM and show that the technique is most suited for studying membrane proteins.

Animals↗
PubMed1998

Activin co-operates with fibroblast growth factor 2 to regulate tyrosine hydroxylase expression in the basal forebrain ventricular zone progenitors.

Activin and its cognate receptors are expressed during embryogenesis in the rapidly dividing cells of the basal forebrain ventricular zone. This finding prompted us to study the role of activin in regulating neurotransmitter phenotype expression and other aspects of the ventricular zone-derived progenitor cell differentiation. Although virtually ineffective alone, activin co-operated with fibroblast growth factor 2 to induce a rapid tyrosine hydroxylase-immunoreactivity in cultured ventricular zone progenitors. Northern analysis indicated that the increase in tyrosine hydroxylase-immunoreactivity was associated with increased tyrosine hydroxylase gene expression. Activin and fibroblast growth factor 2 action was specific to tyrosine hydroxylase, as it did not induce the expression of choline acetyltransferase, nor enhance the expression of glutamate decarboxylase. Cultures treated with the DNA replication marker bromodeoxyuridine revealed that both proliferating ventricular zone progenitors and their post-mitotic progeny were induced to express tyrosine hydroxylase. In these cultures, activin acted to reduce fibroblast growth factor 2 stimulated mitotic activity. Furthermore, activin permitted neuronal differentiation and survival of the ventricular zone progenitors after three days in vitro. Together these data demonstrate a novel role of activin and fibroblast growth factor 2 in regulating the fate of the embryonic basal forebrain ventricular zone progenitors.

Activin Receptors↗
PubMed1998

Left frontal EEG coherence reflects modality independent language processes.

Previous studies showed that distinct components of higher cognitive processes like memorizing of words could be correlated with changes in different frequency bands of the human EEG. This study was designed in order to find out if 1) some frequency bands show power and coherence changes only due to the modality of presented stimuli (either auditory or visual) and 2) if other frequency bands show modality independent effects which should reflect real cognitive-linguistic differences between word classes (either concrete and abstract nouns). EEG was recorded from sixteen right-handed females which had to memorize auditorily and visually presented concrete and abstract nouns. Results show the alpha-1 band to reveal no differences between word classes but demonstrate an influence of modality of stimulus presentation. The only modality independent differences between concrete and abstract noun processing were found in the delta, theta and beta-1 band at left frontal electrodes.

Alpha Rhythm↗
PubMed1998

Listeriolysin O: cholesterol inhibits cytolysis but not binding to cellular membranes.

Listeriolysin O (LLO) binds to cholesterol-containing membranes in which it oligomerizes to form pores. Preincubation of the toxin with cholesterol is known to inhibit haemolysis, whereas the oxidized form of cholesterol has no inhibitory effect. Using immunoblot analyses and flow cytometry we demonstrate that preincubation with cholesterol does not influence binding of the listeriolysin-cholesterol complex to red blood cells, eukaryotic cells or artificial membranes. Lytic activity of membrane-bound LLO inactivated by cholesterol can be restored by enzymatic treatment with cholesterol oxidase. To determine the step at which cholesterol inhibits lytic activity, we looked for pore formation using electron microscopy. Pores formed by purified listeriolysin could be directly visualized using erythrocyte ghosts. This property was lost upon incubation of the toxin with cholesterol. Quantitative analysis strongly suggest that inhibition of lysis by cholesterol is not due to decreased binding of listeriolysin to target membranes, but rather to an interference with a subsequent step leading to polymerization of the toxin.

Animals↗
PubMed1998

The acoustic and structural properties of the human femur.

This study evaluates the variations in the acoustic properties of the human femur at ten evenly spaced locations along its length, as well as differences that exist within given transverse sections. Six pairs of human femora, three male and three female, were sectioned, ground, and polished, and scanned with a microprocessor-driven scanning acoustic microscope. Images with a resolution of approximately 140 microns were used to calculate the average acoustic impedances for each transverse cross section and each quadrant within a cross section. The mean acoustic impedance for all the cross sections was 7.69 +/- 0.18 Mrayls. Variations were observed among the cross sections, and the central sections (4-7) had values that were statistically greater than the other more distal and proximal sections. Within the cross sections, the posterior quadrant had a lower average acoustic impedance compared to the other quadrants and this was statistically significant (Tukey's multiple comparison test). The cross sections were further analyzed to determine several geometric parameters including the principal moments of inertia, polar moment of inertia, and the biomechanical shape index. The product of the acoustic impedance and the maximum moment of inertia provided a result that attempted to account for the acoustic property variation and the change in shape at the different section locations.

Acoustics↗
PubMed1998

Peripheral serotonin levels in women: role of aging and ethnicity.

Serotonin has been implicated to play an important role in regulating emotions and behavior, and it is well accepted that the platelet serotonergic system mirrors the presynaptic central serotonergic system. Since prevalence of psychiatric problems increases with age and women are known to be more vulnerable than men, the present investigation was carried out to study the relationship between serotonin activity and age in women. Levels of serotonin (5-hydroxytryptamine, 5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) were measured in platelets and plasma in women (n = 49) aged 40-84 years (30 women aged 40-60 years and 19 women aged 61-84 years). There was a significant age difference between the two groups (mean: 47.6 +/- 5.91 years in the younger and 73.0 +/- 6.83 years in the older women, respectively, p < 0.00001). Platelet 5-HT as well as 5-HIAA levels were significantly higher in older women as compared to those in the younger women (89.41 +/- 21.95 ng/10(8) platelets in younger vs. 112.9 +/- 36.07 in older women, p < 0.02, and 1.20 +/- 1.10 in younger vs. 2.19 +/- 1.88 ng/10(8) platelets in older women, p < 0.05, respectively). Pearson correlation coefficients determined in the combined group (n = 49) showed a significant positive correlation between platelet 5-HT and age (r = 0.31, p < 0.03). Plasma 5-HT levels on the other hand were lower in older women compared to those in the younger women (4.50 +/- 3.20 in younger vs. 1.04 +/- 1.28 ng/ml plasma in older women, p < 0.0001) and a significant negative correlation was observed between plasma 5-HT and age (r = -0.44, p < 0.002). Plasma 5-HIAA concentration did not differ between the two groups. Platelet 5-HT levels in the younger group were independent of ethnicity. Since high serotonin activity has also been associated with psychiatric problems, our results of increased concentration of platelet 5-HT as well as 5-HIAA with age may have implications in predisposing aging women to behavioral/psychiatric problems.

Adult↗
PubMed1998

Efficacy and safety of acarbose in insulin-treated patients with type 2 diabetes.

OBJECTIVE: To demonstrate the efficacy, tolerability, and safety of acarbose compared with placebo in patients with type 2 diabetes inadequately controlled with diet and insulin. RESEARCH DESIGN AND METHODS: A multicenter randomized double-blind placebo-controlled parallel-group comparison study was conducted. The trial was 26 weeks with a 2-week screening period and a 24-week period of treatment with acarbose or placebo, with forced titration from 25 mg t.i.d. to 50 mg t.i.d. after 4 weeks, and titration of 50 mg t.i.d. to 100 mg t.i.d. after 12 weeks based on glucose control. The dosage of insulin was to remain stable. The primary efficacy variable was mean change from baseline in HbA1c, and secondary efficacy variables included mean changes in fasting and postprandial plasma glucose and triglyceride levels. RESULTS: The addition of acarbose to the treatment of patients receiving background insulin and diet therapy resulted in a statistically significant reduction in mean HbA1c of 0.69% compared with placebo. There were statistically significant reductions in postprandial plasma glucose and glucose area under the curve, and in postprandial serum triglyceride levels in the acarbose-treated patients. Gastrointestinal side effects were more frequently reported in the acarbose-treated patients. There were no significant differences in hypoglycemic events or liver transaminase elevations between groups. CONCLUSIONS: This study demonstrated that the addition of acarbose to patients with type 2 diabetes who are inadequately controlled with insulin and diet is safe and generally well tolerated and that it significantly lowers HbA1c and postprandial glucose levels.

Acarbose↗
PubMed1998

Technetium-99m-MAG3 in early identification of pyelonephritis in children.

UNLABELLED: The purpose of this study was to determine whether 99mTc-mercaptotriacetylglycine (MAG3) can substitute for 99mTc-glucoheptonate (GH) in the detection of pyelonephritis. METHODS: One hundred thirty renal scintigraphies were evaluated retrospectively in 38 children (21% boys, 79% girls; age range 1 mo-21 yr; mean age 7.2 yr) referred for evaluation during an acute clinical urinary tract infection and for follow-up studies. Twelve topographical regions were designated on each kidney. Each area was graded for severity of decreased radionuclide localization: mild (Grade 1), moderate (Grade 2) or marked (Grade 3). Early posterior views of MAG3 studies were compared to delayed posterior GH images. In all patients, both studies were performed on the same day. RESULTS: Eighty-two studies were performed during an acute clinical infection and 48 were performed as follow-up. Seventy-seven percent of the studies had focal cortical lesions. Of all the cortical lesions identified by GH, MAG3 detected 74% (match lesions). A comparable percentage of lesions was identified in each region by both studies. GH scintigraphy detected 261 lesions (63 Grade 1, 149 Grade 2 and 49 Grade 3), and MAG3 detected 201 lesions (37 Grade 1, 117 Grade 2 and 47 Grade 3). MAG3 was unable to recognize 60 lesions identified by GH studies in 11 patients (mismatch lesions). Of these, 41% (26 of 63) were Grade 1, 21% (32 of 149) were Grade 2 and 4% (2 of 49) were Grade 3. In three cases, MAG3 identified lesions not seen by GH (reverse mismatch); all had acute symptomatic infection. CONCLUSION: These data document that MAG3 in the early phase of the study (1-2 min) can detect Grade 2 to Grade 3 cortical lesions in patients with pyelonephritis, but it is less effective in detecting Grade 1 lesions.

Child↗
PubMed1998

Ultrasound biomicroscopy in the diagnosis and management of anterior segment tumors.

BACKGROUND: High-frequency ultrasound biomicroscopy has allowed eye care specialists to evaluate posterior extension of anterior segment tumors. This article evaluates the role of ultrasound biomicroscopy for the diagnosis and management of anterior segment tumors. METHODS: Fourteen patients with anterior segment tumors were selected for evaluation. Each patient underwent a complete clinical examination followed by slit-lamp photography and ultrasound biomicroscopy. RESULTS: Unlike standard ultrasonography of anterior segment tumors, high-frequency ultrasound biomicroscopy allowed quantitative measurements of tumor size, extension within and posterior to the iris, as well as differentiation of solid and cystic lesions. These characteristics were used to differentially diagnose anterior segment tumors and document the response of iridociliary body melanomas to radiotherapy. CONCLUSIONS: This study demonstrates how ultrasound biomicroscopy has become an effective and necessary procedure, used for both the diagnosis and management of anterior segment tumors.

Adult↗
PubMed1997

Oral somatic transgene vaccination using attenuated S. typhimurium.

An attenuated strain of S. typhimurium has been used as a vehicle for oral genetic immunization. Eukaryotic expression vectors containing truncated genes of ActA and listeriolysin--two virulence factors of Listeria monocytogenes--have been used to transform S. typhimurium aroA. Multiple or even single oral immunizations with such transformants induced excellent cellular and humoral responses. In addition, protective immunity was induced with listeriolysin transformants. The quality of the responses suggested a transfer of plasmid DNA from the bacterial carrier to the host. Such transfer was unequivocally shown in vitro with primary peritoneal macrophages. We describe a highly versatile system for antigen delivery, identification of protective antigens for vaccination, and efficient generation of antibodies against the product of open reading frames present on virtually any DNA segment.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed1997

Cost-utility analysis of a malignant glioma protocol.

PURPOSE: To perform a cost-utility analysis utilizing a cooperative group protocol and constrasting the results with the published quality adjusted survival. METHODS AND MATERIALS: A cost-utility analysis was performed on Radiation Therapy Oncology Group (RTOG) protocol 83-02. The quality-adjusted survival has been published previously. Pretreatment tests and chemotherapy costs are not considered, as these were similar across all treatment arms. Payor costs are calculated from Federal Register data for Medicare Region IV. Global charges are used to calculate the professional and technical charges. Costs are measured in relative value units (RVUs) and are tabulated assuming equal treatment complexity for all treatment arms. RESULTS: The number of RVUs calculated for each arm were 48 Gy--166.65; 54.4 Gy--182.17; 64.8 Gy--232.53; 72.0 Gy--272.19; 76.8 Gy--287.11; and 81.6 Gy--302.63. The RVU/QALY for the <50-year-old group were 48 Gy--119.03; 54.4 Gy--100.65; 64.8 Gy--104.78; 72.0 Gy--90.73; 76.8 Gy--193.99; and 81.6 Gy--165.37. The RVU/QALY for the >50-year-old group were 48 Gy--198.39; 54.4 Gy--276.85; 64.8 Gy--426.57; 72.0 Gy--423.71; 76.8 Gy--703.70; and 81.6 Gy--519.10. Sensitivity analysis of one treatment plan, simulation, and set of blocks for the 48 Gy and 54.4 Gy arms decreased the RVU/QALY to 105.34 and 90.05, respectively. DISCUSSION: Our analyses shows the experimental arm with the lowest RVU/QALY is also the arm with the longest quality-adjusted survival. This arm had the most efficient use of resources in this protocol. Prospective collection of all pertinent cost data is required for comparison of one treatment against another. All cooperative group protocols should have prospective quality of life and economic endpoints to allow for comparison of the most cost efficient treatment method.

Brain Neoplasms↗
PubMed1997

T-cell anergy induced by antigen presenting cells treated with the hemolysin of Listeria monocytogenes.

Antigen presenting cells (APC) that are infected with listeriolysin (LLO) secreting Listeria lack the ability to stimulate MHC class II restricted T-cells by conventional antigens. Similarly, T-cell activation by native proteins but not by peptides was inhibited upon pretreatment of APC with purified listeriolysin. The inhibition is due to an irreversible inactivation of T-cells that recognize antigen on infected or LLO treated APC. Inhibition was found to dominate over stimulation by peptides. This condition is reminiscent of T-cells inactivation by antagonistic peptides and represents a novel type of immune escape.

Amino Acid Sequence↗
PubMed1997

[Knowledge of adolescents about the fetal alcohol syndrome].

The level of knowledge of the risks of drinking during pregnancy in 175, 17-18 years olds from kibbutzim in the eastern Upper Galilee was studied in January 1996. This population had the highest rate of involvement with alcohol in Israel and had been involved in alcohol education activities in previous years. About 53.71% of the sample believed that heavy drinking increases the risk of birth defects, but only 20.57% could correctly describe the fetal alcohol syndrome.

Adolescent↗
PubMed1997

[Characteristics of hospitalized alcoholics].

The background characteristics of 1,173 alcoholics hospitalized for 3 months in this center during December 1982 to December 1994 were reviewed. Socio-demographic variables and termination-of-treatment data, are described. The profile of the typical hospitalized alcoholic was that of a Jewish, urban, married, unemployed man, born in Asia-Africa (or in Israel) who had been living for many years in Israel and had many children and a low educational level. They usually start drinking in adolescence and come to the center after more than 15 years of drinking, mainly at home and alone, and also have family relatives who drink. Implications of the data for treatment and for family physicians are presented.

Alcoholism↗