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At least 937 records · Page 52Linked to original sources
PubMed2001

On-line coupling of a miniaturized bioreactor with capillary electrophoresis, via a membrane interface, for monitoring the production of organic acids by microorganisms.

Capillary electrophoresis (CE) can be a valuable tool for on-line monitoring of bioprocesses. Production of organic acids by phosphorus-solubilizing bacteria and fermentation of UHT milk were monitored and controlled by use of a membrane-interfaced dialysis device and a home-made microsampler for a capillary electrophoresis unit. Use of this specially designed sampling device enabled rapid consecutive injections without interruption of the high voltage. No additional sample preparation was required. The time resolution of monitoring in this particular work was approximately 2 h, but could be reduced to 2 min. Analytes were detected at low microg mL(-1) levels with a reproducibility of approximately 10%. To demonstrate the potential of CE in processes of biotechnological interest, results from monitoring phosphate solubilization by bacteria were submitted to qualitative and quantitative analysis. Fermentation experiments on UHT milk showed that monitoring of the processes by CE can provide good resolution of complex mixtures, although for more specific, detailed characterization the identification of individual substances is needed.

Acetic Acid↗
PubMed2002

Serum human chorionic gonadotropin measurements may predict pregnancy outcome and multiple gestation after in vitro fertilization.

OBJECTIVE: To predict pregnancy outcome and multiple gestation using a common parameter by which hCG values are made comparable independently of the day of blood sampling. DESIGN: Retrospective study. SETTING: University-based IVF program. PATIENTS: One hundred twenty IVF pregnancies conceived between November, 1995 and August, 1999. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Early pregnancy loss (preclinical and first trimester abortions, ectopic pregnancies) or ongoing pregnancies (singleton and multiple deliveries, second trimester abortions). Day 11 hCG levels were calculated assuming an exponential increase of hCG values in early pregnancy. Receiver-operating characteristic analysis was used to determine cut-off levels with the best sensitivity and specificity for the prediction of pregnancy outcome. RESULTS: Serum hCG levels in the group of early pregnancy loss were significantly lower than in ongoing pregnancies. A cut-off level of 50 IU/L predicts pregnancy outcome with a sensitivity of 75% and a specificity of 81%, while an hCG value >135 IU/L predicts a multiple ongoing pregnancy with a sensitivity of 80% and a specificity of 88%. CONCLUSION: After IVF, early pregnancy loss or multiple gestation may be predicted with high sensitivity and specificity by using cut-off values of serum hCG derived from two measurements independently of the day of blood sampling.

Abortion, Spontaneous↗
PubMed1994

Treatment of infantile spasms.

OBJECTIVE: To summarize and evaluate the literature regarding the clinical features, epidemiology, etiology, pathophysiology, and treatment of infantile spasms. DATA SOURCES: A literature search of articles from January 1966 to July 1993 using MEDLINE, EM-Base, and Current Concepts/Life Sciences, as well as bibliographies of relevant articles. STUDY SELECTION: All identified original and review publications regarding the clinical features, epidemiology, etiology, pathophysiology, and treatment of infantile spasms were reviewed. Emphasis was placed on original studies published since 1975. DATA EXTRACTION: Data from published research were extracted and evaluated according to study design, sample size, dosing regimen, outcome measures, and treatment efficacy and safety. DATA SYNTHESIS: Infantile spasms constitute a rare epileptic syndrome with a poor long-term prognosis for normal intellectual development. The spasms are characterized by a brief symmetric contraction of the muscles of the neck, trunk, and/or extremities, often occurring in a series of 2 to more than 100 spasms during a single episode. The disorder is age-specific, with the peak onset of symptoms occurring between 2 and 8 months of age. Spasms of no identifiable cause in infants with normal development prior to the onset of infantile spasms are classified as cryptogenic or idiopathic, whereas those with an identifiable cause are classified as symptomatic. Long-term prognosis is best in cryptogenic cases, with 30-70 percent attaining normal intellect compared with 5-19 percent in symptomatic cases. The etiology and pathophysiology are not well understood. Recent theory postulates that infantile spasms may be caused by an excess of corticotropin-releasing hormone activity during infancy. The suspected association between the whole-cell pertussis vaccine and infantile spasms is coincidental. Few well-designed, prospective, controlled clinical trials for the treatment of infantile spasms have been conducted. CONCLUSIONS: Standard anticonvulsants such as phenytoin, the barbiturates, carbamazepine, and the succinimides have been ineffective. Of the anticonvulsants, only the benzodiazepines, valproic acid, and vigabatrin have shown efficacy in reducing spasm frequency and severity. Hormonal therapy with adrenocorticotropic hormone (ACTH) and/or prednisone has been the most frequently studied treatment modality and appears to be the most effective. Hormonal therapy achieves complete spasm control in 50-75 percent of infants within four weeks of initiation. Opinions differ regarding the relative efficacy between ACTH and prednisone, the need for early initiation of hormonal treatment, and the benefits of high dosages of ACTH (> 40 units/d). No treatment has been shown conclusively to improve the long-term intellectual development of these infants. Neurosurgery may be the treatment of choice in select cases when a localized central nervous system abnormality can be demonstrated. Well-designed, blind, prospective clinical trials are needed to answer definitively many lingering questions regarding the treatment of infantile spasms.

4-Aminobutyrate Transaminase↗
PubMedDate not supplied

[Prevalence of tuberculosis infection in the school age in Guadalajara, Spain].

OBJECTIVES: To estimate the prevalence of tuberculosis infected children in the first grades of Primary Education and to analyse the distribution of infected people among social class groups and other previous circumstances. METHODS: Cross-sectional study with diagnostic test application and questionnaire survey, in a representative sample of the school population of the province of Guadalajara, Spain (two stages sampling design). Tuberculin skin tests with 2 I.U. of P.P.D. RT-23 and the Sokal method for lecture were used. For occupational classification and social class definition were used the criteria of the last report of Spanish Epidemiology Society. RESULTS: A total of 1,093 children (50.8% males) between 6 and 9-year-old were studied. The overall prevalence of infected children was 1.64 (I.C.:1-2.3). The distribution of infection did not show significant differences between urban/rural population, previous disease, family antecedent, social class, dwelling area and occupational activities of parents. The prevalence increased in the older upper school years and among the older children. Prevalence ranged from 0.4% (CI: 0.01-1.3) in the first year to 3.53% (CI: 2.4-4.6) in the last year. Children born in 1988 had a 3.23% prevalence (CI: 1.2-5,1), while those born in 1989; 1990 and 1991 had a prevalence of 0.73 (CI: 0-1.77), 1.88% (CI: 0.2-3.51) and 0.4% (0-1.2), respectively. CONCLUSIONS: Tuberculosis infection is less prevalent at school ages than other areas of Spain. In spite of the increase prevalence per school year, the low frequency and sample size did not allow to test for other associations.

Age Factors↗
PubMed1988

[Possibility of the current segregation analysis to discriminate between monogenic and multifactorial types of inheritance of traits. The effect of the structure of family data on model robustness and power of the analysis].

The influence of sampling designs for robustness of the autosomal major locus model and the multifactorial model as well as possibility of segregation analysis to discriminate these models was studied. Nuclear families and 3-generation pedigrees were considered. It was found that robustness of models increased, when the size of sibships in nuclear families grows and when configuration of pedigrees is complicated. The resolution power of the analysis is always increased with size elevation of sibships, the highest effect of the analysis being observed for sibships of the size 3 or 4. Consideration of new generations is only advisable, if attracting sibs of these generations, the resolution power being increased, provided that the parameters of models are of high value.

Genetics, Population↗
PubMed2002

Historical biogeography and molecular systematics of the Indo-Pacific genus Dascyllus (Teleostei: Pomacentridae).

The phylogeographical and systematic relationships among species in the tropical marine fish genus Dascyllus were inferred using mitochondrial DNA (mtDNA) sequence data. Although our results were generally consistent with previously published phylogenies based on both morphological and mitochondrial data, our broad taxonomic and geographical sampling design revealed novel insights into the phylogenetic history of Dascyllus that had escaped previous notice. These results include: (a) the polyphyletic nature of D. reticulatus mtDNAs, representing two divergent and geographically separated lineages, one shared with D. flavicaudus and the second forming the sister lineage of D. carneus; (b) the paraphyly of D. trimaculatus relative to the closely related D. abisella; and (c) phylogeographical structure within the widespread taxa D. aruanus and D. trimaculatus. Application of a molecular clock permits us to posit a causative role for tectonic and oceanic changes regarding some Dascyllus speciation events. Finally, we mapped body size and the presence or absence of protogynous sex change on the mtDNA tree, and tested published hypotheses regarding determinants of the evolution of mating system and protogyny in the genus. Our data rejected a model based on body size but not one based on phylogenetic inertia. The ability to change sex arose once in the ancestor to the entire genus, and was lost once in the ancestor of the D. trimaculatus complex. For taxa that are as geographically widespread as many Indo-Pacific genera, this study highlights the importance of adequate geographical sampling when inferring patterns of species diversification and life history evolution.

Animals↗
PubMed1991

Effects of anabolic-androgenic steroids on muscular strength.

OBJECTIVE: To assess the effects of anabolic-androgenic steroids on human muscle strength. DATA SOURCES: A MEDLINE search for the period from January 1966 to April 1990, supplemented by manual searches of previous reviews, produced 30 studies in which subjects received more than one dose of the study steroid and in which changes in muscular strength were measured. STUDY SELECTION: Of the 30 studies, 14 were not included in the detailed data summary because they did not use a placebo control, did not randomize subjects to groups, or did not make objective strength measurements, or because percent change in strength data could not be abstracted. DATA EXTRACTION: Details of study design, reporting of results, and the adequacy and correctness of statistical methods were tabulated. Percent improvement in strength for the largest muscle group studied was computed, using the difference between results for the placebo and for the steroid-treated groups. DATA SYNTHESIS: Previously trained athletes show slightly greater improvements in strength in the anabolic-androgenic steroid-treated group than in the placebo group, with a median difference of 5% across the nine studies (range, 1.2% to 18.7%). A meta-analysis of the three studies with enough information to compute effect size showed a mean difference of 1.0 standard deviations (95% CI, 0.49 to 1.5). However, the poor overall quality of the studies in terms of design, sample size, and analysis; the lack of a dose-response effect across the narrow range of dosages tested; and the tendency for differences to be smaller in the larger studies throw these results into question. No evidence was found to support enhanced muscle strength with steroid use in eight studies in untrained normal volunteers. CONCLUSIONS: Anabolic steroids may slightly enhance muscle strength in previously trained athletes. No firm conclusion is possible concerning the efficacy of anabolic steroids in enhancing overall athletic performance. Results for the low steroid dosages studied in the published reports cannot be generalized to steroid-using athletes taking megadose regimens.

Anabolic Agents↗
PubMed2005

US valuation of the EQ-5D health states: development and testing of the D1 valuation model.

PURPOSE: The EQ-5D is a brief, multiattribute, preference-based health status measure. This article describes the development of a statistical model for generating US population-based EQ-5D preference weights. METHODS: A multistage probability sample was selected from the US adult civilian noninstitutional population. Respondents valued 13 of 243 EQ-5D health states using the time trade-off (TTO) method. Data for 12 states were used in econometric modeling. The TTO valuations were linearly transformed to lie on the interval [-1, 1]. Methods were investigated to account for interaction effects caused by having problems in multiple EQ-5D dimensions. Several alternative model specifications (eg, pooled least squares, random effects) also were considered. A modified split-sample approach was used to evaluate the predictive accuracy of the models. All statistical analyses took into account the clustering and disproportionate selection probabilities inherent in our sampling design. RESULTS: Our D1 model for the EQ-5D included ordinal terms to capture the effect of departures from perfect health as well as interaction effects. A random effects specification of the D1 model yielded a good fit for the observed TTO data, with an overall R of 0.38, a mean absolute error of 0.025, and 7 prediction errors exceeding 0.05 in absolute magnitude. CONCLUSIONS: The D1 model best predicts the values for observed health states. The resulting preference weight estimates represent a significant enhancement of the EQ-5D's utility for health status assessment and economic analysis in the US.

Adult↗
PubMed2004

Prevalence of idiopathic hypertrophic cardiomyopathy in China: a population-based echocardiographic analysis of 8080 adults.

PURPOSE: To determine the prevalence of hypertrophic cardiomyopathy in China. METHODS: This epidemiologic investigation was performed in 8080 adults from nine communities across nine provinces in China from October 2001 to February 2002, using a multistage, random sample design. Hypertrophic cardiomyopathy was defined as nondilated ventricular hypertrophy, documented by echocardiography, that was not caused by any known cardiac or systemic disease. RESULTS: Of the 4064 men and 4016 women who were screened, 13 (0.16%; 9 men and 4 women) had definite echocardiographic evidence for hypertrophic cardiomyopathy. The age- and sex-adjusted prevalence was about 80 per 100,000 adults. CONCLUSION: Hypertrophic cardiomyopathy is not rare in China. Based on the estimated prevalence, there are at least 1 million cases in China.

Adolescent↗
PubMed1999

Comparison of bolus versus fractionated oral applications of [13C]-linoleic acid in humans.

BACKGROUND: The endogenous conversion of linoleic acid into long-chain polyunsaturated fatty acids is of potential importance for meeting substrate requirements, particularly in young infants. After application of [13C]-linoleic acid, we estimated its conversion to dihomo-gamma-linolenic and arachidonic acids from only two blood samples. DESIGN: Oral tracer doses were given to five healthy adults as a single bolus. In four subjects the tracer was given in nine equal portions over 3 days. Concentration and 13C content of fatty acids from serum phospholipids were analysed by gas chromatography combustion isotope ratio-mass spectrometry. Areas under the tracer-concentration curves were calculated, and fractional transfer and turnover rates estimated from compartmental models. RESULTS: The median fractional turnover of linoleic acid was 93.7% per day (interquartile range 25.3) in the bolus group and 80. 0% per day (6.3) in the fraction group (NS). Fractional conversion of linoleic to dihomo-gamma-linolenic acid was 1.5% (0.9) vs. 2.1% (0.7) (bolus vs. fraction, P < 0.05), and fractional conversion of linoleic to arachidonic acid was 0.3% (0.3) vs. 0.6% (0.3) (bolus vs. fraction, NS). In the fraction group conversion was significantly higher based on areas under the curve. The ratio of tracer concentration in conversion products to linoleic acid 48 h after dosing correlated very well (r >/= 0.94, P < 0.05) with the ratio of areas under the curve. CONCLUSIONS: Using areas under the curve overestimates the conversion, because different residence times are not considered. Estimation of conversion intensity appears possible with only one blood sample obtained after tracer application.

8,11,14-Eicosatrienoic Acid↗
PubMedDate not supplied

Sound level exposure of high-risk infants in different environmental conditions.

PURPOSES: To provide descriptive information about the sound levels to which high-risk infants are exposed in various actual environmental conditions in the NICU, including the impact of physical renovation on sound levels, and to assess the contributions of various types of equipment, alarms, and activities to sound levels in simulated conditions in the NICU. DESIGN: Descriptive and comparative design. SAMPLE: Convenience sample of 134 infants at a southeastern quarternary children's hospital. MAIN OUTCOME VARIABLE: A-weighted decibel (dBA) sound levels under various actual and simulated environmental conditions. RESULTS: The renovated NICU was, on average, 4-6 dBA quieter across all environmental conditions than a comparable nonrenovated room, representing a significant sound level reduction. Sound levels remained above consensus recommendations despite physical redesign and staff training. Respiratory therapy equipment, alarms, staff talking, and infant fussiness contributed to higher sound levels. CONCLUSION: Evidence-based sound-reducing strategies are proposed. Findings were used to plan environment management as part of a developmental, family-centered care, performance improvement program and in new NICU planning.

Child Development↗
PubMed1998

Diagnostic utility of two commonly used ADHD screening measures among special education students.

OBJECTIVE: To examine the diagnostic utility of two commonly used attention-deficit hyperactivity disorder (ADHD) screening measures in a population of special education students and address whether screener performance is affected by demographic characteristics. METHOD: A school district population of special education students was screened for ADHD risk using two parent questionnaires, the 46-item Attention Deficit Disorders Evaluation Scale (ADDES) and the 10-item Conners Abbreviated Symptom Questionnaire (ASQ). All high-risk children and a random sample of low-risk children subsequently underwent DSM-IV-based diagnostic assessment through parental diagnostic interviews (Diagnostic Interview Schedule for Children Version 3.0). Diagnostic utility was summarized by sensitivity, specificity, predictive utilities of positive and negative tests, and efficiency, all of which were estimated using an approach that accounted for the sampling design. RESULTS: Overall efficiency scores ranged between 70% and 74%. Sensitivity estimates were below 70% even at low screener cutoff scores. The ADDES did not perform significantly better than the ASQ. Significant gender and ethnicity effects emerged. CONCLUSIONS: Overall, both the ASQ and the ADDES yielded substantial numbers of false positives and false negatives among this population of children, indicating that alternative approaches will be required to accurately and efficiently identify children in need of services for ADHD. Child psychiatrists can play a valuable consulting role as school districts and primary care settings struggle to implement appropriate identification procedures for ADHD.

Attention Deficit Disorder with Hyperactivity↗
PubMed1997

A secondary analysis of smoking among rural and urban youth using the MTF data set.

This paper compares rural and urban youth cigarette-smoking behavior using the Monitoring the Future data set, a national, probability-based, multi-stage sample design. Cigarette smoking was examined by region, race, and gender over time. Results indicated that rural White males smoked more often (30-day prevalence of 34%) than any other group. Urban Black males smoked the least (10%). Urban White females smoked more (30-day prevalence of 33%) than urban Black females (7%). In general, rural and urban Whites reported smoking at significantly higher rates than rural and urban Blacks. Smoking rates declined steadily for both rural and urban Black females and urban Black males over the study period. These data document distinctive patterns of tobacco use among the nation's youth, which can be used by program planners for specific targeted interventions.

Adolescent↗
PubMed2003

Linkage analysis of cross-sectional and longitudinally derived phenotypic measures to identify loci influencing blood pressure.

BACKGROUND: The design of appropriate strategies to analyze and interpret linkage results for complex human diseases constitutes a challenge. Parameters such as power, definition of phenotype, and replicability have to be taken into account in order to reach meaningful conclusions. Incorporating data on repeated phenotypic measures may increase the power to detect linkage but requires sophisticated analysis methods. Using the simulated Genetic Analysis Workshop 13 data set, we have estimated a variety of systolic blood pressure (SBP) phenotypic measures and examined their performance with respect to consistency among replicates and to true and false positive linkage signals. RESULTS: The whole-genome scan conducted on a dichotomous hypertension phenotype indicated the involvement of few true loci with nominal significance and gave rise to a high rate of false positives. Analysis of a cross-sectional quantitative SBP measure performed better, although genome-wide significance was again not reached. Additional phenotypic measures were derived from the longitudinal data using random effects modelling for censored data with varying levels of covariate adjustment. These models provided evidence for significant linkage to most genes influencing SBP and produced few false positive results. Overall, replicability of results was poor for loci, representing weak effects. CONCLUSION: Longitudinally derived phenotypes performed better than cross-sectional measures in linkage analyses. Bearing in mind the sample design and size of these data, linkage results that fail to replicate should not be dismissed; instead, different lines of evidence derived from complementary analysis methods should be combined to prioritize follow up.

Adult Children↗
PubMed1999

Estimated occurrence of tobacco, alcohol, and other drug use among 12- to 18-year-old students in Panama: results of Panama's 1996 National Youth Survey on Alcohol and Drug Use.

This report provides the first epidemiological evidence on tobacco, alcohol, and other drug use among school students in Panama, using data from a student survey completed in 1996. Specifically, we examine sex, age, grade level, type of school, and urban-rural variations in the occurrence of tobacco, alcohol, and other drug use. Estimates of lifetime prevalence and past-year use of these products were obtained using data from Panama's 1996 National Youth Survey on Alcohol and Drug Use (n = 6,477). To account for the multistage sampling design of the survey, all estimates and respective standard errors are derived by the Taylor series approximation method using Epi Info 6.0 CSAMPLE software. In general, more males, more older students, and more students in higher grades have used licit and illicit drugs, even though male-female differences tend to be small. Public-private school differences and urban-rural trends vary depending on the drug. The findings of this study are discussed in relation to the epidemiology and prevention of drug use in Panama. Based on these data, we seek to provide information to be used by the Government of Panama in its planning for prevention programs directed toward students in Panamanian schools.

Adolescent↗
PubMed1997

Can the blood pressure predict cognitive task performance in a healthy population sample?

OBJECTIVES: To study the relation between the blood pressure and the neurocognitive function within the full adult age range in a large population sample. DESIGN: A cross-sectional study of 936 healthy adults who were recruited from a register of family practices, stratified for age (24-81 years), sex, and occupational level, who took part in a medical and neurocognitive test program. METHODS: The blood pressure status was studied in relation to five measures of cognitive ability, including verbal memory and speed of information processing. Other vascular risk factors were treated as control variables and included smoking, alcohol intake, body mass index, and body fat distribution. The blood pressure was measured five times using an automatic recording technique (with a Dinamap 8100 device). RESULTS: After adjustment for age, sex, and educational level in a hierarchical regression analysis, we found no unequivocal association between the mean systolic and diastolic blood pressures (or any other studied vascular risk factor) and cognitive test performance both for the whole group and for the subgroup of subjects who were not being administered antihypertensive medication and whose medical history did not include cardiovascular events. Stratified analysis within four age levels revealed no age-specific associations between the blood pressure and the cognitive function. Subjects whose blood pressure was within the hypertensive range performed worse than did matched controls at letter digit copying, but not according to other cognitive measures. CONCLUSIONS: With a population-based sample unselected for blood pressure status we found no linear relationship between the actual blood pressure level and various aspects of cognitive performance. Prospective studies are needed to investigate the possibility that the systemic blood pressure load over time is associated with a decline in specific cognitive abilities.

Adult↗
PubMed2000

The efficacy of "distant healing": a systematic review of randomized trials.

PURPOSE: To conduct a systematic review of the available data on the efficacy of any form of "distant healing" (prayer, mental healing, Therapeutic Touch, or spiritual healing) as treatment for any medical condition. DATA SOURCES: Studies were identified by an electronic search of the MEDLINE, PsychLIT, EMBASE, CISCOM, and Cochrane Library databases from their inception to the end of 1999 and by contact with researchers in the field. STUDY SELECTION: Studies with the following features were included: random assignment, placebo or other adequate control, publication in peer-reviewed journals, clinical (rather than experimental) investigations, and use of human participants. DATA EXTRACTION: Two investigators independently extracted data on study design, sample size, type of intervention, type of control, direction of effect (supporting or refuting the hypothesis), and nature of the outcomes. DATA SYNTHESIS: A total of 23 trials involving 2774 patients met the inclusion criteria and were analyzed. Heterogeneity of the studies precluded a formal meta-analysis. Of the trials, 5 examined prayer as the distant healing intervention, 11 assessed noncontact Therapeutic Touch, and 7 examined other forms of distant healing. Of the 23 studies, 13 (57%) yielded statistically significant treatment effects, 9 showed no effect over control interventions, and 1 showed a negative effect. CONCLUSIONS: The methodologic limitations of several studies make it difficult to draw definitive conclusions about the efficacy of distant healing. However, given that approximately 57% of trials showed a positive treatment effect, the evidence thus far merits further study.

Complementary Therapies↗
PubMed2002

Biofilm formation in a hot water system.

The biofilm formation rate was measured in situ in a hot water system in an apartment building by specially designed sampling equipment, and the net growth of the suspended bacteria was measured by incubation of water samples with the indigeneous bacteria. The biofilm formation rate reached a higher level in the hot water distribution system (2.1 d(-1) to 2.3 d(-1)) than in the hot water tank (1.4 d(-1) to 2.2 d(-1)) indicating an important area for surface associated growth. The net growth rate of the suspended bacteria measured in hot water from the top, middle and bottom of the hot water tank, in the sludge, or in the water from the distribution system was negligible. This indicated that bacterial growth took place on the inner surfaces in the hot water system and biofilm formation and detachment of bacteria could account for most of the suspended bacteria actually measured in hot water. Therefore, attempts to reduce the number of bacteria in a hot water system have to include the distribution system as well as the hot water tank.

Bacteria↗