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S Weiss

Publications and source records attributed to S Weiss.

At least 253 records · Page 14Linked to original sources
PubMed1994

Dietary sodium intake and the risk of airway hyperreactivity in a random adult population.

BACKGROUND: High dietary sodium intake has been identified as a potential cause of asthma and airway hyperreactivity. This study was designed to test the hypothesis that dietary sodium intake is an independent determinant of the risk of hyperreactivity in the general population, and to assess the role of atopy in the association between these factors. METHODS: Airway reactivity to methacholine, atopy, 24 hour urinary sodium excretion, and self-reported smoking and symptom history were measured in a random sample of 1702 adults aged 18-70 from an administrative district of Nottingham. Hyperreactivity was defined as a PD20FEV1 of 12.25 mumol or less, and atopy was defined quantitatively as the mean allergen skin weal response to Dermatophagoides pteronyssinus, cat fur, and grass pollen, and categorically as the occurrence of any allergen response 1 mm or greater than the saline control. Multiple logistic regression analysis was used to estimate the independent relative odds of hyperreactivity, atopy, or symptoms in relation to sodium excretion in all 1702 subjects, and multiple linear regression to assess the independent relation between sodium excretion and mean allergen skin weal diameter, and the PD20 value amongst hyperreactive subjects. RESULTS: There was no relation between the relative odds of hyperreactivity to methacholine and 24 hour urinary sodium excretion, either before or after adjustment for age, smoking, allergen skin weal diameter, and sex, and similarly no relation if the analysis was restricted to men or women only. The relative odds of having at least one allergen skin test response 1 mm greater than the saline control were increased in relation to sodium excretion after adjustment for age, sex, and smoking by a ratio of 2.08 (95% CI 1.04 to 4.15) per log10 unit increase in sodium excretion, but there was no evidence of an association between sodium excretion and the occurrence of self-reported wheeze, hay fever, eczema, or asthma. There was no relation between 24 hour sodium excretion and the magnitude of the mean allergen skin weal response or the PD20 value. CONCLUSIONS: These findings do not support the hypothesis that a high dietary sodium intake is a risk factor for airway hyperreactivity or atopic disease in the general adult population.

Adolescent↗
PubMed1994

The relationships between casual and ambulatory blood pressure measurements and central hemodynamics in essential human hypertension.

OBJECTIVE: To determine the association between ambulatory blood pressure (ABP) and central hemodynamics in hypertensive patients and between the area under the 24-h blood pressure curve and the hemodynamic indexes. PATIENT POPULATION: Forty untreated essential hypertensive patients (28 previously untreated, 12 withdrawn from therapy for > 12 weeks). METHODS: Patients underwent casual and 24-h ABP monitoring and invasive measurements of central hemodynamics. Central measures of ABP included 24-h mean, awake, and sleep values guided by activity journals. The ABP data were modeled by Fourier series and the ability of the smoothed and unsmoothed data to predict hemodynamics was compared. Individual blood pressure curves were analyzed by calculating the area under the curve using different threshold awake and sleep values to test the correlations between this form of blood pressure load and hemodynamics. RESULTS: Hemodynamic measures were not predicted by casual blood pressure but were related to ABP. Total peripheral resistance was strongly predicted by the area under the diastolic blood pressure (DBP) curve using an awake threshold of 90 mmHg and a sleep threshold of 80 mmHg (r = 0.56, P < 0.001). Data smoothing using Fourier transformation did not alter any correlations between ABP and hemodynamics. Exercise stroke index, an indicator of cardiac function impaired in early hypertensive heart disease, was also best predicted by area under the DBP curve using the same thresholds as above (r = -0.56, P < 0.001). CONCLUSIONS: These data imply that integrated areas under the ABP curve are related to hemodynamic hypertensive indexes and could be used to assess the extent of hypertensive burden in clinical trials.

Adult↗
PubMed1994

Thymic selection of immunoglobulin idiotype specific T-cells.

The thymus is the major site for differentiation and maturation of developing T-cells. The diversity in the T-cell repertoire is generated during ontogeny by rearrangements of T-cell receptor gene segments that encode clonally distributed receptors. Most of the newly produced thymocytes that bear alpha beta TCR die in the thymus as a consequence of at least two selective processes. Those that can react to self MHC antigens survive (positive selection), but only if the binding affinity for the same or other self MHC (probably complexed with self peptides) molecules is not too high (negative selection). As a result, each T-cell that has acquired functional competence in the thymus should have a certain degree of self-MHC specificity. Our comprehension of thymic development has been aided by the study of transgenic mice that bear functionally rearranged TCR or Ig lambda light chain genes. To study positive selection we analyzed transgenic mice with alpha beta TCR genes isolated from a T-cell clone specific for an idiotypic peptide of lambda 2(315) (a mutant of the lambda 2 Ig chain) bound to the E(d) MHC class II molecule. The results suggest that positive selection of some thymocytes might be weak, reminiscent of a 'struggle for survival', since the selected population was small and had high levels of transgenic receptor and coreceptor (CD4) molecules. The thymic tolerance mechanism was also investigated using a combination of both TCR and lambda 2(315) transgenic mice. The clonal deletion of Id specific thymocytes was influenced by the production site as well as the concentration of the lambda 2(315) antigen. In conclusion, the interaction avidity of a single thymocyte, which is important for selective processes, might be affected by the expression levels of each interacting component: TCR, CD4 or CD8 and MHC molecule and self antigen.

Animals↗
PubMed1994

Why, where and with whom do Israeli teenagers drink? To whom do they turn for help with alcohol problems?

This article describes preferred sources of support after having drinking problems, reasons for drinking and the social context of drinking of 1458 Israeli adolescents in the North of Israel in winter 1992. The article analyses the results by gender, grade and place of living (large city, small or developing town, kibbutz, religious settlement). Most teenagers drink with same-age friends, their preferred location of drinking is the pub and enjoyment is their most prevalent reason for drinking. The majority of the sample chose parents as the main source of support in cases of having problems with alcohol. The study provides pointers towards environmental approaches in the prevention of problem drinking.

Adolescent↗
PubMed1994

The T alpha 1 alpha-tubulin promoter specifies gene expression as a function of neuronal growth and regeneration in transgenic mice.

We have previously demonstrated that one member of the alpha-tubulin multigene family, termed T alpha 1 in rats, is regulated as a function of neuronal growth and regeneration. To elucidate the molecular mechanisms responsible for coupling gene expression to morphological differentiation, we have isolated the T alpha 1 gene, have fused 1.1 kb of the 5' flanking region to a nuclear lacZ reporter gene, and have generated transgenic mice. Analysis of these transgenic mice demonstrated that marker gene expression was specific to the CNS and PNS, with expression in vivo at embryonic day 13.5 being similar to expression of the endogenous gene. Moreover, the induction of transgene expression was correlated temporally with neuronal commitment in developing neural crest-derived peripheral neurons and in the developing retina. Immunocytochemical analysis of mixed primary embryonic brain cultures confirmed that transgene expression was specific to neurons, with the majority of neurons, but not astrocytes or oligodendrocytes, expressing beta-galactosidase. Transgene expression in vivo was maintained in developing neurons until early in postnatal life, subsequent to which its expression decreased coincident with neuronal maturation. The transgene was then reinduced in regenerating facial motoneurons following unilateral axotomy of the facial nerve. Thus, 1.1 kb of 5' flanking sequence from the T alpha 1 gene contains the sequence elements responsible for specifying gene expression to embryonic neurons and for subsequently regulating gene expression in both developing and mature neurons as a function of morphological growth.

Animals↗
PubMed1994

Factors influencing the occurrence of airway hyperreactivity in the general population: the importance of atopy and airway calibre.

The factors that determine the occurrence of airway hyperreactivity in the general population are not clearly understood. This study was designed to assess the independent effects of age, atopy, smoking and airway calibre. In a random sample of 2,415 adults aged 18-70 yrs we measured reactivity to methacholine as the dose provoking a 20% fall (PD20) in one-second forced expiratory volume (FEV1), atopy as the mean skin wheal response to three common environmental allergens, and airway calibre as the baseline FEV1 in absolute terms, as percent predicted (FEV1 % predicted) and as percent forced vital capacity (FEV1 % FVC). Hyperreactivity, defined as a PD20 < or = 12.25 mumol, was present in 314 (13%) of the sample, and before adjustment for FEV1 was more common in females (independent odds ratio (OR) = 2.05 (95% confidence interval 1.6-2.7)), current smokers (OR = 1.89 (1.3-2.6)), atopics (OR = 1.39 (1.3-1.5) per mm skin wheal), and in older age groups (OR for age 60-70 yrs relative to 18-29 yrs = 2.70 (1.7-4.3)). However, the odds of hyperreactivity were also strongly and independently related to absolute FEV1 (OR = 0.46 (0.27-0.77) per litre), FEV1 % predicted (OR = 0.96 (0.94-0.98) per percent), and FEV1 % FVC (OR = 0.92 (0.90-0.94) per percent; combined chi-square on 3 df = 312, p << 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Follow-up with bone scintigraphy using tomography emission technique (SPECT) after reconstruction of the mandible with iliac crest transplants].

Fifteen patients who underwent mandibular reconstruction with iliac bone grafts where studied by single photon emission computed tomography (SPECT). Six of these patients underwent mandibular reconstruction with revascularized iliac bone grafts. Long-term follow up data by free bone grafts and revascularized bone grafts where very different. The single photon emission computed tomography (SPECT) is an excellent method for the assessment of the vascular patency and bone viability.

Bone Transplantation↗
PubMed1993

Repeated NMDA receptor activation induces distinct intracellular calcium changes in subpopulations of striatal neurons in vitro.

The mechanisms underlying long-term calcium changes evoked by excitatory amino acids have not been previously examined in striatal neurons. Fura-2 fluorescence measurements were used to examine intracellular calcium concentration ([Ca2+]i) changes due to repeated N-methyl-D-aspartate (NMDA) receptor activation, in primary cultures of murine striatal neurons. Three applications of 200 microM NMDA (for 2 min, each application separated by 7 min), in 0 magnesium-containing artificial cerebral spinal fluid, elicited three distinct responses. In 50 +/- 8% of the NMDA-responsive neurons, no persistent increases in [Ca2+]i (final [Ca2+]i < or = 150% baseline) were observed, while in 33 +/- 7% and 17 +/- 3% of the cells, sustained (peak response > final [Ca2+]i > 150% baseline) and uncontrolled increases (final [Ca2+]i > or = peak response) were observed, respectively. NMDA-responsive neurons that were intensely immunoreactive for the calcium binding protein calbindin-D28k never exhibited uncontrolled increases in [Ca2+]i. Removal of extracellular Ca2+ significantly attenuated sustained, but not uncontrolled, increases in [Ca2+]i; sustained increases in some neurons were also attenuated by application of verapamil (100 microM) or MK-801 (1 microM). Pre-treatment of striatal neurons with the protein kinase C blocker sphingosine (20 microM), virtually eliminated the development of sustained or uncontrolled increases in [Ca2+]i. These findings suggest that specific intracellular mechanisms regulate the distinct [Ca2+]i responses of subpopulations of striatal neurons to repeated NMDA receptor activation.

Animals↗
PubMed1993

The multimerization state of retroviral RNA is modulated by ammonium ions and affects HIV-1 full-length cDNA synthesis in vitro.

Genomic human immunodeficiency virus type 1 (HIV-1) RNA fragments containing the dimer linkage structure (DLS) can be dimerized and multimerized in the presence of NH4+ and in the absence of any other cation and any viral or cellular protein. This effect strongly supports the notion that dimerization and multimerization of genomic RNA occurs via purine-quartet formation in quadruple helical RNA structures. The efficiency of RNA dimerization and multimerization in the presence of ammonium ions is about 400 fold increased as compared to alkali metal ions such as potassium. Dimerized retroviral RNA representing a pseudodiploid genome could account for genetic recombination within the virion and during reverse transcription. Application of a novel South-Northern-Blotting procedure with biotinylated RNA and digoxigenin-labelled cDNA in vitro reveals that efficient human- and bovine tRNA(Lys3) primed full-length cDNA-synthesis only takes place with a predominantly monomerized RNA template. Dimerization and multimerization of the RNA significantly reduces full-length cDNA-synthesis. This suggests that monomerization of the dimerized RNA, effected by deionization in vitro, is essential for efficient retroviral reverse transcription in vivo.

Acetates↗
PubMed1993

Molecular approach to identifying route of transmission of tuberculosis in the community.

There is growing concern that tuberculosis is spread in Europe in the way that it is in the USA. We have used DNA "fingerprinting" in a systematic evaluation of tuberculosis cases notified in our community to uncover foci of transmission. An IS6110 probe was used to test all isolates from culture-confirmed tuberculosis cases (163 patients) notified in 1991-92 in the Canton of Berne. In total, 45 patients (27.6%), potentially linked on the basis of restriction fragment length polymorphism, were investigated epidemiologically. The largest group (n = 22) included members of a defined social group (drug addicts, homeless persons, alcoholics), from whom tuberculosis spread to the general population. A key patient developed multidrug-resistant tuberculosis during the surveillance period. This population study showed that (i) extensive transmission of Mycobacterium tuberculosis is now taking place in Europe in the same social setting as in the USA; (ii) there is definite "spillover" to the general population; (iii) the dimensions of the problem cannot be recognised easily by routine public health service activities because of the complexity of the transmission network; and (iv) multidrug-resistant tuberculosis develops in this setting.

Adult↗
PubMed1993

[Alcohol and AIDS].

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Maintenance drug treatment of panic disorder. I. Results of a prospective, placebo-controlled comparison of alprazolam and imipramine.

One hundred six patients diagnosed according to DSM-III as suffering from agoraphobia with panic disorder, panic disorder with limited phobic avoidance, or uncomplicated panic disorder entered an acute 8-week treatment phase. Patients who improved received an additional 6 months' maintenance treatment. Significantly more patients treated with alprazolam than with imipramine hydrochloride or placebo remained in therapy and experienced panic attack and phobia relief during the acute treatment phase. During the maintenance phase, neither tolerance nor daily dose increase was observed. All patients who completed the maintenance phase (27 in the alprazolam group, 11 in the imipramine group, and 10 in the placebo group) were panic free at the end of 8 months of study treatment. Alprazolam therapy was effective and well tolerated at a mean daily dose of 5.7 mg. Imipramine hydrochloride (175 mg/d) also produced significant panic relief but was associated with poor patient acceptance.

Adult↗
PubMed1993

Maintenance drug treatment for panic disorder. II. Short- and long-term outcome after drug taper.

Forty-eight patients with panic disorder completing 8 months of maintenance treatment with alprazolam (mean dose, 5.2 mg [n = 27]), imipramine hydrochloride (mean dose, 175 mg [n = 11]), or placebo (mean dose, 8.0 pills [n = 10]) underwent a gradual taper from medication over a 4-week period. A withdrawal syndrome was observed in almost all alprazolam-treated patients but in only a few imipramine- or placebo-treated patients. The clinical worsening of withdrawal symptoms after discontinuation tended to subside over the course of 3 medication-free weeks, but 33% of alprazolam-treated patients were unable to discontinue their medication regimen successfully. Severity of panic attacks at baseline but not daily alprazolam dose appeared as a significant independent predictor of taper difficulty. Forty-nine percent of the total study population continue to receive drug therapy: 82% alprazolam and 18% imipramine. Among patients who received alprazolam during study treatment and at follow-up, the mean daily dose was substantially reduced (6.1 vs 1.6 mg [n = 14]). At follow-up, after 1 year of naturalistic treatment for panic symptoms and combining 8-month completers and study dropouts, there were no significant differences in remission (68% to 71%) or in antipanic medication intake (39% to 56%) at follow-up for the three original treatment groups. However, 8-month study completers compared with study dropouts had a significantly higher remission rate (85% vs 55%).

Adult↗
PubMed1993

Clonal deletion of specific thymocytes by an immunoglobulin idiotype.

We have investigated whether immunoglobulin can induce clonal deletion of thymocytes by employing two strains of transgenic mice. One strain is transgenic for an alpha/beta T cell receptor (TCR) which recognizes a processed idiotypic peptide of the lambda 2(315) light chain variable region, bound to the I-Ed class II major histocompatibility complex molecule. The other mouse strain is transgenic for the lambda 2(315) gene. Double transgenic offspring from a TCR-transgenic female mated with a lambda 2(315) transgenic male exhibit a pronounced clonal deletion of CD4+CD8+ thymocytes. Analysis of neonates from the reciprocal (lambda 2(315)-transgenic female x TCR-transgenic male) cross suggests that the deletion in double transgenic offspring most likely is caused by lambda 2(315) produced within the thymus rather than by maternally derived IgG, lambda 2(315). Nevertheless, IgG, lambda 2(315) can cause deletion of CD4+CD8+ thymocytes when injected in large amounts intraperitoneally into either adult or neonatal TCR-transgenic mice. Deletion is evident 48 and 72 h after injection, but by day 7 the thymus has already regained its normal appearance. A serum concentration of several hundred microgram/ml is required for deletion to be observed. Therefore, the heterogeneous idiotypes of serum Ig are probably each of too low concentration to cause thymocyte deletion in normal animals.

Animals↗
PubMed1993

Growth and physiological functions of vascular endothelial cells in a new serum-free medium (SFM).

Endothelial cells grown in vitro are widely used for the study of vascular physiology and pathology. The high levels of serum supplementation normally used in endothelial cell culture may create problems in experimental design or in interpretation of results. A serum-free medium (SFM) has been designed specifically for culture of nonhuman vascular endothelial cells. Growth as well as retention of various physiological markers in this medium was demonstrated in large-vessel endothelial cells from bovine, porcine, ovine, and canine species. Cells from all species tested took up DiI-acetylated LDL. Factor VIII-related antigen was demonstrated in cultures of bovine and canine cells. Bovine and porcine cells were shown to have retained the ability to produce prostacyclin. Further supplementation of the SFM with various lipid-containing additives failed to stimulate either growth or prostacyclin production. PDGF produced by bovine, porcine, and canine endothelial cells was measured and found to be present at lower concentration than in serum supplemented cultures. All cells grown in SFM exhibited the histiotypic "cobblestone" morphology normally associated with cultured endothelial cells. While not optimized for culture of human endothelial cells, short-term growth < or = 4 passages) of human umbilical vein endothelial cells was achieved by supplementing the SFM with hydrocortisone, bovine pituitary extract, and epidermal growth factor.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Diurnal growth rhythms in the chicken eye: relation to myopia development and retinal dopamine levels.

1. If the eyes of young chickens are deprived of clear vision by translucent occluders, they develop considerable amounts of axial myopia within days. At the same time, the day time retinal dopamine levels drop by about 30%. Because the retinal dopamine levels of normally sighted chicks also differ diurnally and are low at night, we expected that the rate of axial eye growth might also differ during this time. 2. Unexpectedly, eyes grew in length only during the day (about 0.13 mm/day) and even shrank during the night (about -0.04 mm/night, average net growth +0.09 mm in 24 h). 3. If the eyes were occluded, they grew both during the day and also at night (average net growth: +0.16 mm in 24 h). Therefore, development of deprivation myopia was a result of the lack of growth inhibition at night rather than of excessive growth during the day when the actual deprivation occurred. 4. Suppression of dopaminergic retinal pathways by intravitreal injections of the neurotoxin 6-hydroxy-dopamine (6-OHDA) also suppressed development of deprivation myopia and it restored the growth inhibition at night. With normal visual experience, the drug had no effect on axial eye growth and refractive state. 5. Diurnal growth rhythms of the eyes disappeared under continuous light.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Arachidonic acid inhibits sodium currents and synaptic transmission in cultured striatal neurons.

In the striatum, dopamine generates arachidonic acid (AA) and induces synaptic depression. Here, we report that Na+ channels are a target for AA in both cultured and acutely isolated striatal neurons. AA depressed veratrine-induced Na+ influx and neurotransmitter release. Whole-cell voltage clamp revealed that peak Na+ currents are depressed, and steady-state inactivation shifts -15 mV in the presence of AA. Furthermore, inactivation was accelerated, and recovery from inactivation was delayed. These actions of AA were not produced by AA metabolites or protein kinase C activation. In addition, AA reduced both the amplitude and frequency of action potentials and depressed spontaneous inhibitory postsynaptic currents without affecting miniature inhibitory postsynaptic currents. These data suggest that AA modulates presynaptic, Na(+)-dependent action potentials, thereby contributing to striatal synaptic depression.

Action Potentials↗