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PubMed1995

Estimates of population size, dispersal, and longevity of domestic Aedes aegypti aegypti (Diptera: Culicidae) by mark-release-recapture in the village of Shauri Moyo in eastern Kenya.

Estimates of the absolute size of a domestic population of Aedes aegypti aegypti (L.) were made in the Rabai area of Kenya, based on a single release, followed by either single or repeated recaptures. From single recapture within 24 h of release, the size of the female Ae. a. aegypti population in the Shauri Moyo village was estimated by the Lincoln index to be 365. Using a single release and repeated recaptures, population size was estimated by Jackson's positive method to be 337. Depletion of the unmarked females by daily removal sampling provided us with two additional, direct estimates of the size of the village population (451 by Kano's method and [464 +/- 18.9 SEM] by the Moran-Zippin method). The longevity of marked females was at least 9 d. The day-to-day movement of marked mosquitoes revealed the dispersal pattern of Ae. a. aegypti among houses clustered within different distance zones. Marked mosquitoes reached all houses of the village within 24 h of release. After 5 d, the dispersion of both marked and unmarked mosquitoes among houses was similar.

Animal Identification Systems↗
PubMed2004

The cost-effectiveness of elective Cesarean delivery to prevent hepatitis C transmission in HIV-coinfected women.

OBJECTIVES: To determine the net health consequences, costs, and cost-effectiveness of elective Cesarean delivery (C-section) to prevent perinatal transmission of hepatitis C virus (HCV) in HIV/HCV-coinfected women with suppressed HIV RNA but detectable HCV RNA. DESIGN: Cost-effectiveness analysis using a probabilistic decision model. METHODS: The model compared two strategies: (i) C-section for all coinfected women with suppressed HIV RNA but detectable HCV RNA; (ii) C-section only when indicated based on fetal status. Outcomes included vertical transmission of HCV, maternal mortality, quality-adjusted life expectancy, delivery and HCV treatment costs, and incremental cost-effectiveness ratios. Data were obtained from the literature and national databases. Delivery cost data were from a hospital consortium database. Probability distributions were derived from published confidence intervals or estimated ranges, or calculated using reported sample sizes. RESULTS: Elective C-section in coinfected women with suppressed HIV RNA but detectable HCV RNA would avoid 45 vertical HCV transmissions per 1000 deliveries and increase maternal mortality by one death per 100 000 deliveries. The incremental cost-effectiveness ratio of a recommendation for C-section versus current practice was 3900-6100 dollars per quality-adjusted life year for the mother-child pair. Results are sensitive to the efficacy of C-section in preventing transmission, the probability of vaginal delivery without a recommendation, and rates of maternal acceptance of the recommendation. CONCLUSIONS: Assuming 2000 births/year among HIV/HCV-coinfected women in the United States, a recommendation for elective C-section in these women could avoid an additional 90 perinatal HCV transmissions per year with a risk of one maternal death in 50 years.

Cesarean Section↗
PubMed1999

Public health workforce information: a state-level study.

A two-stage sample survey was used to estimate the size of Texas' professional public health workforce and to describe its composition in terms of employment settings, job characteristics, and individual characteristics. The estimated 17,700 public health professionals employed in 1995 represented approximately three percent of the state's total health workforce. About 55 percent of all these professionals worked in agencies that provide population-based public health services. An estimated seven percent had formal public health education. These findings raise issues concerning the numerical adequacy of the state's supply of public health professionals, the adequacy of their educational preparation, and the human resources capacity of the state's official public health agencies.

Adult↗
PubMed1998

Effects of damp and mould in the home on respiratory health: a review of the literature.

This review examines whether there is a direct or indirect relation between damp or mould in the home and respiratory health. Home dampness is thought to have health consequences because it has the potential to increase the proliferation of house-dust mites and moulds, both of which are allergenic. The results from the many studies conducted to investigate whether damp and mould are associated with health outcomes are difficult to compare because the methods of measuring exposures and health outcomes have not been standardized. However, the studies that have been conducted in children are probably the most reliable because the confounding effects of active smoking or occupational exposures are absent, and because the presence of symptoms of cough and wheeze have been consistently investigated in many studies. The increased risk of children having these symptoms if the home has damp or mould is fairly small with an odds ratio that is generally in the range 1.5-3.5, these estimates being statistically significant when the sample size has been large enough. This range is consistent with the measured effects of other environmental exposures which are considered important to health, such as environmental tobacco smoke or outdoor air pollutants. The potential benefits of reducing mould in the home have not been investigated, and the few studies that have investigated health improvements as a result of increasing ventilation or reducing damp in order to reduce house-dust mite levels suggest that this intervention is expensive, requires a large commitment, and is unlikely to be successful in the long term. This implies that houses need to be specifically designed for primary prevention of respiratory problems associated with indoor allergen proliferation rather than using post hoc procedures to improve indoor climate and reduce allergen load as a secondary or tertiary preventive strategy.

Animals↗
PubMed1988

Paternal absence and sex-role development: a meta-analysis.

A meta-analysis was based on every available study that has compared father-present and father-absent children on a measure of sex typing. 67 studies produced 222 estimates of effect size. Owing to the inappropriateness of conventional statistics, Hedges's approach to meta-analysis was employed. Results show that published studies produced larger estimates of effect size than dissertations and conference papers. Effect-size estimates based on clinical and incarcerated samples were significantly different from those based on more typical samples. Generalizable differences between father-present and father-absent females were conspicuously absent. Preschool father-absent boys were shown to make less stereotypical choices of toys and activities when compared to father-present age-mates. When compared to father-present boys, older father-absent boys were more stereotypical in their overt behavior, particularly in terms of aggression. Discussion focused on interpretation of the results within a multidimensional conception of sex role.

Adolescent↗
PubMed1998

Detection of individual variation in enzyme activity in natural populations of Drosophila melanogaster.

The method allows the determination of the activity level of enzymes in a single fly and assessing the genetic composition of the given individual at these enzyme loci. Three isofemale lines were constructed which were monomorphic at several enzyme loci. Samples were prepared in two different ways: (i) individual samples--individuals were homogenised separately; (ii) collective samples--a common homogenate was prepared from several individuals. Oregon-R strain was also used to prepare a standard homogenate. The activities of alcohol dehydrogenase (ADH), alpha-glycerophosphate dehydrogenase (alpha GPDH), isocitrate dehydrogenase (IDH), and 6-phosphogluconate dehydrogenase (6PGDH), were measured in each sample on starch gel after the proteins were separated by electrophoresis. Enzyme activities were assessed by the optical density of the bands. Gel and position weights were estimated on the basis of the statistical analyses of the activities measured in the standard samples. Gel weights were then used to account for the activity differences among the gels while position weights were applied to correct for the general tendencies in the activities observed within the gels. The gel and position weighted activities of individual and collective samples were compared in the isofemale lines. The individual samples had approximately two times as much variation as the collective samples for all four enzymes. The electrophoretic method is sensitive enough to study the structure of the phenotypic variation in enzyme activity in the natural populations. The total variation among the standard samples was close to the within subline component of variation obtained for the collective samples (measurement error). This shows that the standard samples can be used to estimate the size of the measurement error.

Alcohol Dehydrogenase↗
PubMed1997

Birth outcomes following zidovudine exposure in pregnant women: the Antiretroviral Pregnancy Registry.

Potential risk of adverse birth outcomes associated with the use of antiretrovirals in human immunodeficiency virus (HIV)-infected women during pregnancy must be assessed. Data through June 1995 are reported from the worldwide Antiretroviral Pregnancy Registry on the incidence of structural birth defects following prenatal exposure to zidovudine. Healthcare professionals register pregnant women anonymously. Follow-up is at time of delivery. Results are reviewed semi-annually by an advisory committee, which follows the Centers for Disease Control and Prevention (CDC) guidelines for definitions of birth defects. From 1989 through to 30 June, 1995, 198 outcomes involving exposure to zidovudine were reported. Of 73 first-trimester exposures, outcomes included one infant with a birth defect. Of 125 exposures in the second and third trimesters, six infants were reported with birth defects. Data on other antiretrovirals are insufficient for analysis. The Registry findings to date do not show an increase in the number of birth defects (1/63 in the first trimester, or 1.59%, 95% CI 0.083%, 9.69%) following prenatal zidovudine exposure when compared with that expected in the general population; however, the number of outcomes to date represents a sample of insufficient size for developing precise estimates regarding the teratogenic risk of zidovudine.

Abnormalities, Drug-Induced↗
PubMed1980

Quantitative studies of the gastrin-producing cells of the human antrum. A methodological study.

The antral gastrin-producing cells (G-cells) have been identified by the indirect immunoperoxidase technique in two antrum preparations removed due to a recurrent duodenal and gastric ulcer. Morphometric principles were applied to the G-cells with determination of their volume density, numerical density, and mean cell volume. The study showed that within-observer variation, between-observer variation and within-patient variation were negligible, provided at least 200 G-cells were counted. A biopsy material can be used, as well as larger tissue blocks, when this minimum sample size is respected. A method for estimating the total G-cell population and the total G-cell volume in the antrum was developed. In the antrum removed due to a gastric ulcer the number of G-cells was 190 x 10(6) and their total volume 176 mm3.

Cell Count↗
PubMed2003

Blindness: how to assess numbers and causes?

BACKGROUND: Traditionally, blindness surveys have modelled themselves on the "gold standard" of a census and examination of a whole population. Blindness, however, is a relatively rare condition even in badly affected communities; hence, large sample sizes are required to gain adequate estimates of prevalence, particularly by cause. METHODS: Three assessments of blindness prevalence and aetiology in the same communities are reported. One involved asking individuals questions concerning their visual status during a census (perceived visual status, PVD), one involved examination of all ostensibly visually disabled people presenting to a central point within each community (examination of the visually disabled, EVD), and the final assessment involved a gold standard examination of the whole population (whole community examination, WCE). RESULTS: In a population of 8139 the blindness prevalence was 2.7% PVS, 3.6% EVD, and 3.1% WCE. Attributed causes of blindness were not representative in the PVS except for cataract. The END yielded cause specific estimates not far from those found at WE except for a relative under-representation of glaucoma and optic atrophy. CONCLUSION: Since cataract is, by a significant margin, the most common cause of blindness in the world such a simple method as asking individuals if they are blind and what they believe to be the cause may yield adequate estimates of the problem for planning eye care strategies for this condition. Alternatively, an ophthalmologist visiting villages and examining allcomers for visual disability may provide reasonably accurate cause specific prevalence estimates without the expense of a major blindness survey.

Adolescent↗
PubMed2005

Developmental dyslexia--recurrence risk estimates from a german bi-center study using the single proband sib pair design.

OBJECTIVE: Several studies have demonstrated a genetic component for dyslexia. However, both segregation and linkage analyses show contradictory results pointing at the necessity of an optimal ascertainment scheme for molecular genetic studies. Previously, we have argued that the single proband sib pair design (SPSP) would be optimal. The aims of this paper therefore are to demonstrate the practicability of the SPSP design and the estimation of recurrence risks for reading and writing. METHODS: We assessed spelling and reading in a family sample ascertained through the SPSP design. 287 families with at least two siblings and their parents were recruited. At least one child was affected with spelling disorder according to a one standard deviation (1SD) discrepancy criterion. RESULTS: Mean values for probands and their siblings were different for both the spelling and the reading phenotype. For the probands, variances of the phenotype spelling were smaller. These effects became stronger with more extreme selection criteria. Both siblings fulfilled the 1SD criterion for spelling and reading in 60.3 and 28.9% of the families, respectively, indicating a low cost efficiency of the double proband sib pair approach. A recurrence risk of 4.52 (CI: 4.07-4.93) was obtained for spelling when the 1SD criterion was applied to both siblings. Recurrence risk estimates were similar for reading. CONCLUSION: The study demonstrates the suitability of the SPSP design for genetic analysis of dyslexia. The recurrence risk estimates may be used for determining sample sizes in gene mapping studies.

Child↗
PubMed2005

Edgeworth approximation of multivariate differential entropy.

We develop the general, multivariate case of the Edgeworth approximation of differential entropy and show that it can be more accurate than the nearest-neighbor method in the multivariate case and that it scales better with sample size. Furthermore, we introduce mutual information estimation as an application.

Algorithms↗
PubMed2004

Assessing intervention effects in a school-based nutrition intervention trial: which analytic model is most powerful?

This article compares four mixed-model analyses valid for group-randomized trials (GRTs) involving a nested cohort design with a single pretest and posttest. This study makes estimates of intraclass correlations (ICCs) available to investigators planning GRTs addressing dietary outcomes. It also provides formulae demonstrating the potential benefits to the standard error of the intervention effect (sigma(delta)) from adjustments for both fixed and time-varying covariates and correlations over time. These estimates will allow other researchers using these variables to plan their studies by estimating a priori detectable differences and sample size requirements for any of the four analytic options. These methods are demonstrated using data from the Teens Eating for Energy and Nutrition at School study. Mixed-model analyses of covariance proved to be the most powerful analysis in that data set. The formulae may be applied to any dependent variable in any GRT given corresponding information for those variables on the parameters that define the formulae.

Adolescent↗
PubMed2003

A randomised controlled trial to assess the efficacy of Laparoscopic Uterosacral Nerve Ablation (LUNA) in the treatment of chronic pelvic pain: The trial protocol [ISRCTN41196151].

BACKGROUND: Chronic pelvic pain is a common condition with a major impact on health-related quality of life, work productivity and health care utilisation. The cause of the pain is not always obvious as no pathology is seen in 40-60% of the cases. In the absence of pathology there is no established treatment. The Lee-Frankenhauser sensory nerve plexuses and parasympathetic ganglia in the uterosacral ligaments carry pain from the uterus, cervix and other pelvic structures. Interruption of these nerve trunks by laparoscopic uterosacral nerve ablation (LUNA) may alleviate pain. However, the balance of benefits and risks of this intervention have not been reliably assessed. LUNA has, nevertheless, been introduced into practice, although there remains controversy regarding indications for LUNA. Hence, there is an urgent need for a randomised controlled trial to confirm, or refute, any worthwhile effectiveness. The principal hypothesis is that, in women with chronic pelvic pain in whom diagnostic laparoscopy reveals either no pathology or mild endometriosis (AFS score </= 5) LUNA alleviates pain and improves life quality at 12 months. METHODS/DESIGN: The principal objective is to test the hypothesis that in women with chronic pelvic pain in whom diagnostic laparoscopy reveals either no pathology or mild endometriosis (AFS score </= 5) LUNA alleviates pain and improves life quality at 12 months. A multi-centre, prospective, randomised-controlled-trial will be carried out with blind assessment of outcomes in eligible consenting patients randomised at diagnostic laparoscopy to LUNA (experimental group) or to no pelvic denervation (control group). Postal questionnaires including visual analogue scale for pain (primary outcome), an index of sexual satisfaction and the EuroQoL 5D-EQ instrument (secondary outcomes) will be administered at 3, 6 and 12 months. The primary assessment of the effectiveness of LUNA will be from comparison of outcomes at the one-year follow-up, although the medium-term and longer-term risks and benefits of LUNA will also be evaluated.The sample size for this trial has been estimated as 420 patients in total using the hypothesis that LUNA will alleviate pain symptoms (i.e. reduce pain scores on a VAS) more than no intervention at one-year following diagnostic laparoscopy and taking into consideration 20% loss to follow-up. The intention to treat analysis to address the principal research questions will be conducted using the one-year follow-up data.

Journal Article↗
PubMed2000

Typical error versus limits of agreement.

We have shown that the SEM (typical error) and LOA are very similar when defined at the same level of abstraction. The calculation of these sample statistics does not depend on sample size, but the precision of their estimate for the population parameter does. Only the latter concept involves the t-statistic. They do differ in the type of measurement error that is described (true score error versus test-retest error) and the coverage probability of the reference interval (0.6 versus 0.95). Bland and Altman and Atdinson and Nevill have promoted the citation of either the SEM or the LOA to help researchers in their discussion of the impact of error to real uses of the measurement tol. What is vital in this discussion is the researcher having a thorough understanding of the underlying theory behind the measurement error statistic(s) that is/are employed, especially the definition of error and the coverage probability that is selected. Such issues have been built into the title of the 95% LOA statistic, and are also an inherent part of SEM. Whilst the concept of typical error appears to be easy to understand and teach, this is only because the underlying theory and definition of what the statistic actually represents is not communicated. Only if all researchers adopt one single statistic (e.g. typical error) for measurement error is it remotely possible to push underlying theory into the background, since there would be a baseline of comparison for all. Because this scenario is highly unlikely, it is important that any measurement error statistic is well defined and understood by researchers.

Confidence Intervals↗
PubMed2006

Body condition assessment using digital images.

This project assessed the ability to assign a body condition score (BCS) to a dairy cow from digital photographs or videos. Images were taken from the rear of the cow at a 0 to 20 degrees angle relative to the tail head. Four observers assigned a BCS to each of 57 cows at a farm visit (live, farm 1) and later from a photograph (photo). Means +/- standard deviations of BCS by method and observer were as follows: live = 3.25 +/- 0.51, 3.42 +/- 0.49, 3.32 +/- 0.58, 3.13 +/- 0.62; photo = 3.36 +/- 0.52, 3.32 +/- 0.43, 3.44 +/- 0.62, 3.14 +/- 0.6 for observers 1 to 4, respectively. Body condition score means differed across observers for live (observer 2 higher and observer 4 lower, compared with observers 1 and 3) and photo methods (observer 3 lower, compared with observers 1, 2, and 3); however, within observer, the mean live BCS did not differ from the mean photo BCS. Correlation coefficients between BCS assigned live and from photos were 0.84, 0.82, 0.82, and 0.90 for observers 1 to 4, respectively. Subsequently, observer 1 visited 2 farms, assigned a live BCS, and digitally photographed 187 cows (56 and 131 cows from farms 2 and 3, respectively). Observers 2, 3, and 4 assigned a BCS from the photographs. Means +/- standard deviations of BCS by observer (method) were 1 (live) 3.35 +/- 0.55; 2 (photo) 3.33 +/- 0.49; 3 (photo) 3.60 +/- 0.54; and 4 (photo) 3.26 +/- 0.62. The mean BCS for observer 3 was higher and that for observer 4 was lower than for observers 1 and 2. Correlation coefficients between observer 1 and observers 2 through 4 were 0.78, 0.76, and 0.79, respectively. Observer 1 assigned a BCS to 41 cows at a farm visit and 3 wk later assessed the BCS of cows from a video taken at a farm visit by a different individual. Cows were restrained in headlocks at a feed bunk when assessing BCS and for video production. No difference was detected for the mean BCS, for the standard deviation of the mean BCS, or in the distribution of BCS between the live and video assessments. Mean and SD for 17 groups of Holstein cows from 20 farms were used to generate 10,000 random samples of BCS. Groups of 25, 50, 100, and 150 cows were created from the random samples, and estimates of mean BCS were determined by sampling 3 to 80% of the group. Estimates of mean BCS with a sample size of 30% or more from a group of cows fell within the 95% confidence limit of the true mean more than 98% of the time. Digital photographs provide adequate imaging for assessment of BCS. Sampling 30% of a group should be adequate to assess the mean BCS. Video imaging allowed a rapid assessment of BCS but did not permit identification of individual cows.

Animals↗
PubMed2026

Clinically Relevant Pharmacogenomic Variant Frequencies in Kazakh, Russian, and Uzbek Population Groups Residing in Kazakhstan.

Central Asian populations remain underrepresented in pharmacogenomic research, limiting the availability of population-specific data for genotype-informed prescribing and precision medicine. This study analyzed clinically relevant pharmacogenomic variant frequencies in Kazakh, Russian, and Uzbek population groups residing in Kazakhstan using genome-wide genotype data from 1301 individuals: Kazakh (n = 1111), Russian (n = 156), and Uzbek (n = 34). ClinPGx, a PharmGKB-based clinical annotation framework that prioritizes variant-drug associations according to levels of evidence, was used to select variants with evidence levels 1A, 1B, and 2A. In total, 112 directly genotyped variants were retained for population-specific allele and genotype frequency analysis. All 112 variants were queried against the gnomAD v4.1 genome and exome reference datasets. Of these, matching allele-frequency data for the predefined reported allele were available in at least one of the two gnomAD datasets for 103 variants, whereas for 9 variants the VEP-based query did not return a matching gnomAD frequency for that allele. Frequencies were reported for the same predefined reported allele across all groups, and differences between the study groups were assessed using 95% confidence intervals, Fisher's exact tests, and false discovery rate correction. Genotype counts and the proportions of individuals carrying at least one copy of the reported allele were also summarized for all selected variants. Several pharmacogenomic variants showed population-specific frequency patterns, including NUDT15 rs116855232, SLCO1B1 rs4149056, VKORC1 rs9934438, and UGT1A1 rs10929302. Comparison with gnomAD showed that the observed frequencies were variant-specific and could not be consistently approximated by a single broad genetic ancestry group. Reference-based population structure analysis provided additional ancestry context and supported separate reporting by population group. The study did not evaluate clinical outcomes or make individual prescribing recommendations, and the small Uzbek sample size limits the precision of frequency estimates for this group, particularly for rare variants. Overall, this study provides a clinically prioritized pharmacogenomic frequency resource for underrepresented population groups in Kazakhstan and supports broader Central Asian representation in pharmacogenomic implementation research.

Central Asia↗
PubMed1996

Ambulatory monitoring of the blood pressure in multicenter clinical trials.

By reducing measurement error associated with clinic (or casual) blood pressure, ambulatory blood pressure measurement (ABPM) potentially enhances the precision of blood pressure estimation. Enhanced precision leads to lower sample size requirements or increased statistical power, or both, in clinical trials. Thus, by virtue of its increased numbers of measurements and improved reproducibility, ABPM can differentiate among active antihypertensive therapies when clinic blood pressure measurements do not. Additional benefits of ABPM can include identification of white-coat hypertensives, removal of observer bias, a marked reduction in placebo effects and evaluation of the circadian blood pressure pattern. By identifying circadian patterns, ABPM aids in the evaluation of the diurnal and nocturnal effects of a therapeutic regimen. ABPM has found more frequent application in the assessment of antihypertensive therapies in multicenter trials in recent years. However, using ABPM in multicenter trials might increase the complexities of the conduct of the trial relevant to the maintenance of homogeneity in study methods. Special concerns for multicenter trials involving ABPM include device use and validation, experience of study coordinators or research technicians and patient compliance. In recent years in the USA, ambulatory blood pressure values have been used to serve as secondary 'cut-off' criteria before random allocation in a trial (after primary entry criteria based on clinical blood pressure values have been satisfied). Sponsors of trials have become highly selective in recruiting study sites with substantial experience in ABPM. These practices may create a more homogeneous cohort in the trial and make the population less representative of the general hypertensive population.

Journal Article↗
PubMed1975

Ovarian changes during early pregnancy in pony mares in relation to PMSG production.

The ovaries of twenty pregnant mares were examined daily, per rectum, for the first 4 months of gestation and note was made of their estimated size and follicular content. Serial blood samples from sixteen of the mares were assayed for PMSG. A marked seasonal effect was noted on ovarian size, follicular content and ovulation rate during pregnancy but there was no such effect on PMSG production. It is concluded that PMSG is synergistic with gonadotrophins of pituitary origin and that the latter hormone are the primary stimulus on the ovary of the pregnant horse.

Animals↗