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Biomedical subjects

M Wiener

Publications and source records attributed to M Wiener.

At least 19 recordsLinked to original sources
PubMed2004

Rapid right ventricular pacing is an alternative to adenosine in catheter interventional procedures for congenital heart disease.

OBJECTIVE: To describe the use of rapid right ventricular pacing to facilitate balloon stability during balloon dilatation procedures for congenital heart disease. SETTING: Tertiary paediatric cardiac centre. DESIGN AND PATIENTS: This was a prospective pilot study of 37 consecutive patients with congenital aortic stenosis undergoing elective balloon dilatation. If the first dilatation manoeuvre failed due to balloon displacement, rapid right ventricular pacing at a rate of 220 beats/min was performed during repeat balloon inflation. INTERVENTIONS: Balloon aortic valvotomy and rapid right ventricular pacing. MAIN OUTCOME MEASURES: Balloon stability versus displacement during balloon dilatation and procedure related complications. RESULTS: Initial balloon displacement occurred and rapid right ventricular pacing was performed in 14 patients. The balloon remained in stable position in 11 patients. In three patients the balloon was displaced. In two of them an increase of the pacing rate to 240 beats/min provided balloon stability. In one patient stability was obtained at an unchanged pacing rate after correction of a suboptimal balloon position. No sustained arrhythmias occurred. There were no other procedure related complications. CONCLUSIONS: Rapid right ventricular pacing is a safe and effective method to provide balloon stability during balloon dilatation of the aortic valve. It may be applied in other fields of catheter intervention where it is desirable to maintain stable device positions during the critical phase of the procedure.

Adenosine↗
PubMed2001

Estimates of the health risk reductions associated with attainment of alternative particulate matter standards in two U.S. cities.

As part of its periodic re-evaluation of particulate matter (PM) standards, the U.S. Environmental Protection Agency estimated the health risk reductions associated with attainment of alternative PM standards in two locations in the United States with relatively complete air quality data: Philadelphia and Los Angeles. PM standards at the time of the analysis were defined for particles of aerodynamic diameter less than or equal to 10 microm, denoted as PM-10. The risk analyses estimated the risk reductions that would be associated with changing from attainment of the PM-10 standards then in place to attainment of alternative standards using an indicator measuring fine particles, defined as those particles of aerodynamic diameter less than or equal to 2.5 microm and denoted as PM-2.5. Annual average PM-2.5 standards of 12.5, 15, and 20 microg/m3 were considered in various combinations with daily PM-2.5 standards of 50 and 65 microg/m3. Attainment of a standard or set of standards was simulated by a proportional rollback of "as is" daily PM concentrations to daily PM concentrations that would just meet the standard(s). The predicted reductions in the incidence of health effects varied from zero, for those alternative standards already being met, to substantial reductions of over 88% of all PM-associated incidence (e.g., in mortality associated with long-term exposures in Los Angeles, under attainment of an annual standard of 12.5 microg/m3). Sensitivity analyses and integrated uncertainty analyses assessed the multiple-source uncertainty surrounding estimates of risk reduction.

Air Pollutants↗
PubMed2000

Body mass index in 17-year-old Israeli males of different ethnic backgrounds; national or ethnic-specific references?

OBJECTIVE: To evaluate whether a single national reference is appropriate for assessing prevalence of overweight in heterogeneous populations, or whether ethnic-specific references are needed. DESIGN: A population-based study of Israeli Jewish males who underwent routine physical and clinical examinations prior to army recruitment served as the basis for the development of two types of references for body mass index (BMI): a national reference (NR) and an ethnic-specific reference (ER). SUBJECTS: Consecutive cohorts of all 17-y-old Jewish male recruits (n=109, 570). MEASUREMENTS: Weight, height and blood pressure values were obtained. BMI was calculated, and the 85th percentile of BMI was used as a cut-off point for overweight, using both types of references. Prevalence of hypertension among recruits was used as a biomarker to support the reliability of the ER when discrepancy in classification between the two references was found. RESULTS: As compared to the NR, three ethnic groups had a BMI distribution shifted to the left (light sub-population) and five were shifted to the right (heavy sub-population). In the light sub-population, 7% of the inductees who were classified as having normal weight by the NR were considered overweight by the ER and had a hypertension rate similar to that of those defined as overweight by both references (3.1 per 1000). In the heavy sub-population the 4% of subjects who were overweight by NR and normal by ER had hypertension rates similar to those defined as normal weight by both references (2.7/1000), and significantly lower than that of those classified as overweight by both references (10.8/1000). CONCLUSION: In heterogeneous populations, ethnic references should be used to evaluate prevalence of overweight, rather than one national reference. International Journal of Obesity (2000)24, 88-92

Adolescent↗
PubMed2000

The effect of full protective gear on intubation performance by hospital medical personnel.

OBJECTIVE: To assess the influence of protective gear on intubation performance. DESIGN: Prospective, controlled measurement of duration and quality of intubations performed on mannequins by medical personnel with and without protective gear in a crossover design. PARTICIPANTS: Eight teams each comprising an anesthesiologist and a nurse. RESULTS: Intubation duration with and without chemical warfare gear was 69.2 +/- 7 and 47.3 +/- 6 seconds (mean +/- SEM), respectively (p < 0.05). Moreover, rating of intubation quality as "very good" by the anesthesiologists declined significantly from 62.5% without chemical warfare protective gear to 6.25% with the garment and mask. Tube fixation was the rate-limiting step when performed with protective gear (p < 0.05); it was assessed by 81% of the anesthesiologists as the critical step. A learning curve was not observed during the study. CONCLUSION: Protective gear causes a significant prolongation of intubation duration; however, endotracheal intubation can be performed effectively. Technical improvements are warranted for tube fixation because it is the critical step.

Adult↗
PubMed1999

Dantrolene and recovery from heat stroke.

Several authors have shown that dantrolene may be effective in the treatment of heat stroke patients. However, the scant data available are still controversial. The aim of this investigation was to establish an animal experimental model for studying the efficacy of this drug both as a prophylactic agent and as a means of hastening the cooling process after heat stroke. Male albino rats were divided into five groups: Sedentary controls (SC), Sedentary+dantrolene (S+D), Exercise controls (EC), and Exercise+dantrolene (E+D, E+D1). The drug (140 mg x kg(-1) body weight) was administered i.v. either prior to subjection to heat stress (40 degrees C) (S+D, E+D) or upon development of heat stroke syndrome (E+D1). In the S+D group, dantrolene administered prior to heat stress (HS) delayed the development of heat stroke by 70%, although colonic temperature (Tc) at the onset of heat stroke was similar to that in group SC (43.0 +/- 0.1 degrees C and 43.2 +/- 0.4 degrees C for S+D and SC, respectively). In E+D animals, dantrolene shortened exercise endurance in the heat by 17.5%, but concomitantly hindered severe Tc rise (40.9 +/- 0.2 degrees C and 40.0 +/- 0.2 degrees C for EC and E+D, respectively). Administration of dantrolene on the development of heat stroke appeared to improve cooling in the exercise group (0.25 degrees C x min(-1) and 0.18 degrees C x min(-1), for the first 1 5 min of cooling, for E+D1 and EC, respectively). The results suggest that dantrolene is effective as a prophylactic agent in sedentary animals only. It also might have application on development of heat stroke. It is hypothesized that the observed rapid cooling is associated with dantrolene's effect on muscle contraction, thus leading to attenuated heat production and peripheral vascular relaxation.

Analysis of Variance↗
PubMed1998

Ion-channel-forming colicins.

Several features of ion-channel-forming colicins have been illuminated by recent revelations: its four-domain structure, the mechanism and thermodynamics of binding to the gating loop of outer membrane porins, the mechanism of translocation, competition for the transperiplasmic excursion facilitated by the Tol or Ton transperiplasmic proteins, and the formation of a waisted, funnel-shaped transmembrane channel of well-characterized shape.

Bacterial Proteins↗
PubMed1998

Usefulness of short-term urine collection in the nutritional monitoring of low birthweight infants.

To establish adequacy of urine collection times shorter than 24h in the metabolic monitoring of low birthweight infants, we collected urine for 24 h in 39 LBW infants during the third and fourth week of life. All urine voidings over the 24-h period were separately collected, the volume of each sampling and the time of voiding were recorded, and 20% of the volume was removed for pooling. All individual and pooled samples were analysed for total nitrogen, urea and ammonia, alpha-amino nitrogen, creatinine, sodium, potassium, calcium and phosphorus, and for each compound the ratio to 1 mol creatinine was established. Individual sample results were "pooled" to obtain 3-, 6- and 12-h period excretion and than related to the 24-h excretion as measured in the pooled 24-h sample. As the volume of urine obtained in any 6-h collecting period depended on the time of sampling (06:00-12:00 h, 17.5+/-3.1% of total; 12:00-18:00 h, 31.6+/-5.1% of total; 18:00-24:00 h, 25.6+/-3.1% of total; and 0:00-06:00h, 25.3+/-2.9% of total), calculations were based on samples obtained from 18:00 to 06:00 h. The correlation between results of 3- and 24 h-collection periods was weakest, while results of the 6-h collection correlated highly with the total daily excretion (r = between 0.82 and 0.93 for the different compounds) and the correlation was only slightly better when the 12-h collection period was considered. The correlation between the mean molar substrate/creatinine ratio of all individual samples of a 24-h collecting period and the and total daily excretion of the respective substrate was weaker (r = between 0.46 and 0.76 for the different compounds) than the correlation between the results of a 6-h collecting period and the daily excretion is not as stable than in later life. The data indicate that 6-h urine sampling may be sufficient for metabolic monitoring of LBW infants. By contrast, urinary substrate/creatinine ratios are not good markers of the daily excretions of the respective substrate during the first weeks of life.

Ammonia↗
PubMed1997

Crystal structure of colicin Ia.

The ion-channel forming colicins A, B, E1, Ia, Ib and N all kill bacterial cells selectively by co-opting bacterial active-transport pathways and forming voltage-gated ion conducting channels across the plasma membrane of the target bacterium. The crystal structure of colicin Ia reveals a molecule 210 A long with three distinct functional domains arranged along a backbone of two extraordinarily long alpha-helices. A central domain at the bend of the hairpin-like structure mediates specific recognition and binding to an outer-membrane receptor. A second domain mediates translocation across the outer membrane via the TonB transport pathway; the TonB-box recognition element of colicin Ia is on one side of three 80 A-long helices arranged as a helical sheet. A third domain is made up of 10 alpha-helices which form a voltage-activated and voltage-gated ion conducting channel across the plasma membrane of the target cell. The two 160 A-long alpha-helices that link the receptor-binding domain to the other domains enable the colicin Ia molecule to span the periplasmic space and contact both the outer and plasma membranes simultaneously during function.

Biological Transport↗
PubMed1997

Age-specific cerebral perfusion in 4- to 15-year-old children: a high-resolution brain SPET study using 99mTc-ECD.

This study addresses the question of whether the normal range for distribution of local cerebral blood flow (lCBF) in adults can be transferred to the 4- to 15-year-old age group. Twenty-three children (age: 4-15 years; mean 11+/-3 years, group I) and 10 adults (age: 27-56 years; mean 45+/-10 years, group II) without evidence of cerebrovascular disease or other brain diseases underwent technetium-99m ethyl cysteinate dimer single-photon emission tomography. Counts in cortical and subcortical regions of interest (ROIs) were related to those in cerebellar ROIs (= 100%). Relative cortical activity in group I exceeded that in group II, particularly in left parietal (107.6%+/-9.8% vs 84.1%+/-12.4%), left frontal (97. 7%+/-6.7% vs 79.4%+/-8.9%) and left temporal areas (99.7%+/-7.4% vs 84.9%+/-10.1%) and in the cingulate cortex (112.1%+/-9.1% vs 95. 9%+/-10.1%, P<0.05). Cerebral activity uptake per injected dose was inversely correlated with age in 19 children of group I (r = -0.77, P<0.001). In group I, there was also an inverse correlation between age and the relative local count density in the parietal (r = -0.42 to -0.57), frontal (r = -0.48), temporal (r = -0.42 to -0.58) and occipital cortex (r = -0.44). In these cortical regions relative counts differed when subgroups of children aged 4-10 and 11-15 years were analysed. It is concluded that there are systematic differences between 4- to 15-year-old children and adults with regard to normal lCBF. Diagnostic use of perfusion agents has to consider age-adjusted normal flow maps; normal ranges should be determined separately for the age groups 4-10 and 11-15 years.

Adolescent↗
PubMed1997

Height and social class in male adolescents from different ethnic backgrounds in Israel.

The relationship between height and social class, independent of the effect of ethnic background was examined. This is a population-based study of 17-year-old israeli-born Jewish males born between 1966-1969 who underwent routine physical examination prior to army recruitment. Inductees descending from 9 ethnic backgrounds-Germany, Hungary, India, Morocco, Poland, Romania, Russia, Yemen and at least 3rd-generation israeli-born were used for this analysis. Anthropometric data was abstracted from the computerized induction examination; socioeconomic status (SES) was assigned according to the residence of each recruit. Statistical analysis included analysis of variance and chi square test for linear trend. Mean height of the total (reference) group was 173.7 cm, ranging from 172.0 cm in the lowest SES level to 175.1 cm in the highest level. The proportion of individuals above the 85th percentile of height of the reference group, increased linearly from 8.7% (lowest SES) to 18.5% (highest SES) (p < 0.01). The mean height of recruits differed considerably among ethnic groups in each SES level and ranged from 170.8 cm (Yemenites) to 175.4 cm (Russian and Romanian) in the total group. In each ethnic group, height differences between extreme levels of SES were observed ranging from 2.3 cm (Morocco) to 4.3 cm (Russia). We conclude that height among 17-year old israeli-born males is positively associated with SES after controlling for ethnicity.

Adolescent↗
PubMed1997

[Age dependence of cerebral Tc-99m-ECD distribution between preschool and school-age children and adults].

AIM: This present study deals with the question whether normal distribution of local cerebral blood flow (ICBF) agents in adults can be transferred to the age group of 4 to 15 years old children. METHODS: 23 children (age: 4-15 years, mean 11 +/- 3 y) (group I) and 10 adults (age: 27-56 years, mean 45 +/- 10 y) (group II) without evidence of cerebrovascular disease or other brain diseases underwent Tc-99m-ECD-SPECT imaging. Counts in the cortical ROIs were related to those of cerebellar ROIs (= 100%). RESULTS: In group I, relative cortical activity exceeded that of group II, particularly in parietal (107.6 +/- 9.8 vs. 84.1 +/- 12.4%), frontal (97.7 +/- 6.7 vs. 79.4 +/- 8.9%), left temporal areas (99.7 +/- 7.4 vs. 84.9 +/- 10.1%) and in the singular cortex (112.1 +/- 9.1 vs. 95.9 +/- 10.1%, p < 0.05). Cerebral activity uptake/injected dose/acquisition period was linearly correlated with age in group I (r = -0.78, p < 0.001). There was also a correlation of the relative local count density with age in 5 parietal ROIs (r = -0.42 to -0.57), in 2 frontal ROIs (r = -0.48), in 7 temporal ROIs (r = -0.42 to -0.58) and in 2 occipital ROIs (r = -0.44). In 14 cortical regions relative counts differed when subgroups of children aged 4-10 and 11-15 years were analysed. CONCLUSION: There are systematic differences between 4 to 15 years old children and adults regarding the normal distribution of ICBF. Diagnostic use of perfusion agents has to consider the respective age-adjusted normal flow maps; respective normal ranges should be determined for age groups of 4-10 and of 11-15 years separately.

Adolescent↗
PubMed1996

Model for outcomes assessment of antihistamine use for seasonal allergic rhinitis.

BACKGROUND: Drug selection for optimal treatment of common medical conditions may be difficult and involve many diverse factors. OBJECTIVE: The efficacy, safety, quality of life, and cost of treatment of seasonal allergic rhinitis with cetirizine, chlorpheniramine, or terfenadine were compared in a prospective, two-phase, randomized, single-blind clinical trial conducted in a managed care setting. METHODS: In phase I, which lasted 2 weeks, patients were randomized to receive one of the study drugs. In phase II, which lasted 4 weeks, the initial treatment was continued unless patients were dissatisfied, in which case they could be randomly assigned to receive another study drug. In both phases pseudoephedrine could be taken as needed. Patients kept daily diaries of symptoms and costs, and study drugs were evaluated at the end of each phase for efficacy, safety, and effect on quality of life by means of a validated questionnaire. A multiattribute outcomes assessment model for formulary decision making was used to rank the antihistamines. RESULTS: Physicians' and patients' assessments in phases I and II indicated that cetirizine and chlorpheniramine were significantly more effective than terfenadine (p < 0.05). Incidence of sedation in phase I and phase II was 40.5% and 16.7% for chlorpheniramine, 11.6% and 9.8% for cetirizine, and 6.7% and 5.1% for terfenadine, respectively. At the end of phase I, 28.9% of the patients treated with chlorpheniramine, 50% of the patients treated with terfenadine, and 69.4% of the patients treated with cetirizine were satisfied with their therapy and chose not to switch their medication. Quality of life scores improved most after treatment with cetirizine and least after treatment with terfenadine. CONCLUSION: The result of this trial indicate that antihistamine selection is best made with the use of a multiattribute evaluation that includes quality of life. In this study cetirizine was favored by patients and physicians most often, followed by chlorpheniramine and then terfenadine.

Adolescent↗
PubMed1996

Relationship between morbidity and extreme values of body mass index in adolescents.

BACKGROUND: Although the association between overweight and cardiovascular risk factors is well documented in cross-sectional and longitudinal studies, reports of adolescent morbidity associated with underweight in industrialized countries are rare. METHODS: This population-based study includes approximately 110,000 17 year old Israeli Jewish males who underwent routine physical examination at army induction centres. Computerized data tapes include overall health profiles, specification of physical and mental conditions, and height and weight measurements. Medically significant conditions are those with sufficient severity to preclude service in a combat unit. RESULTS: Functional limitation is more prevalent at both extremes of the body mass index (BMI) distribution: 149.5/1000 among severely underweight individuals and 164.3/1000 among severely overweight subjects. Overweight was associated with hypertension (14.9/1000 among the severely overweight), as well as joint conditions of the lower extremities, mainly hip, ankle and knee disorders. Functional disorders associated with underweight are bronchial and lung conditions, including asthma (14.2 and 18.9/1000 in the mildly and severely underweight), scoliosis, intestinal conditions and emotional disorders (mainly neurosis). CONCLUSIONS: Both under- and overweight are associated with morbidity at age 17. Intervention programmes should begin at an early age.

Adolescent↗
PubMed1996

The remuneration of dentists in a special project of the Israeli Defence Forces.

The behavior of health care professionals is known to be influenced, in part, by their method of remuneration and the financial incentives they face. Describes how the Medical Corps of the Israel Defence Forces (IDF) went about choosing a reimbursement method to increase incentives for dentists and decrease waiting time for the public. Based on q questionnaire sent to all 23 dentists working in a unique IDF civilian dental clinic, and on other information which was available on the productivity and income of these dentists, a new method of remuneration was suggested and accepted, by which a combined method of fee-for-service and salary will be introduced. The base hourly pay and per crown fee were set on levels which provide for a larger compensation range and increase the incentive for improved productivity levels. This suggested method will be investigated further and re-evaluated one year after its implementation.

Attitude of Health Personnel↗
PubMed1996

The "cyclic" regimen of low-dose doxycycline for adult periodontitis: a preliminary study.

Specially-formulated low-dose doxycycline (LDD) regimens have been found to reduce collagenase activity in the gingival tissues and crevicular fluid (GCF) of adult periodontitis subjects in short-term studies. In the current, double-blind, placebo-controlled study, adult periodontitis patients were administered for 6 months a "cyclical" regimen of either LDD or placebo capsules; and various clinical parameters of periodontal disease severity, and both collagenase activity and degradation of the serum protein, alpha 1-PI, in the GCF were measured at different time periods. No significant differences between the LDD- and placebo-treated groups were observed for plaque index and gingival index. However, attachment levels, probing depth, and GCF collagenase activity and alpha 1-PI degradation were all beneficially and significantly (P < 0.05) affected by the drug regimen. We propose: 1) that LDD inhibits tissue destruction in the absence of either antimicrobial or significant anti-inflammatory efficacy; and 2) that long-term LDD could be a useful adjunct to instrumentation therapy in the management of the adult periodontitis patient.

Adult↗
PubMed1995

The characteristics of bronchial asthma among a young adult population.

A total of 107, 636 subjects of both sexes who were drafted into the Israeli Defense Forces during 1986 to 1988 were analyzed for the presence of asthma based on questionnaire responses and the results of pulmonary function tests. Most patients (79%) had either mild or inactive disease. Lifetime prevalence increased by 21.7% from 5.3% in 1986 to 6.5% in 1988. The results of a follow-up carried out over 5 to 7 years showed no major change in severity in most patients. The incidence rate remained stable throughout 1987 to 1989 (275, 245, and 243 per 100,000, respectively), without there being any major change in the severity of the asthma during the subsequent 3 to 5 years. It was also revealed that the more physically demanding jobs were associated with a higher prevalence of job transfer. The results of this study suggest that the factors causally associated with asthma are relatively more active during early childhood.

Adult↗