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At least 505 records · Page 28Linked to original sources
PubMed1994

[Pneumonia in patients undergoing heart surgery].

OBJECTIVE: We performed a follow-up study of 104 consecutive patients who underwent cardiac surgery to ascertain the following: 1) the incidence of nosocomial pneumonia (NP) in this patient population; 2) the differences in the incidence of NP between patients who underwent coronary artery bypass grafting (CABG) vs. valvular replacement (VR), and 3) the identification of risk factors which predispose patients to the development of NP. RESULTS: The study included 104 patients of which 49 underwent VR, 43 CABG and 12 who had both procedures performed simultaneously. Six of the 104 patients developed NP (5.7%). Five of these patients had undergone VR where as opposed to only one in the CABG group. Pulmonary hypertension preoperatively was a risk factor for the development of NP. Of the 49 patients in the VR group, 46 had pulmonary artery pressures (PAP) recorded, and from their 23 (50%) had pulmonary hypertension. However, 4 of the 5 (80%) patients who developed NP had elevated PAP. The mortality among patients with NP was high. Sixty six percent of patients (4/6) with NP died in comparison to the 10 deaths (10.2%) among 92 patients without NP (p = 0.002). CONCLUSIONS: A trend in the development of NP was observed in patients who underwent valve replacement as opposed to CABG. Because of the small number of patients who developed pneumonia in the study population statistical significance cannot be reached. Pulmonary hypertension in the post operative period is a risk factor for the development of NP. Mortality among patients who develop NP is significantly high (p = 0.002).

Adult↗
PubMed1994

[Polymorphism of the TAP genes Japanese healthy control and type I diabetes mellitus].

Stable cell surface presentation of MHC class I molecules requires active transport of antigenic peptides across the endoplasmic reticulum by products of two genes, TAP1 and TAP2, which are maped in the MHC class II region. There are many human diseases whose onset are associated with particular MHC alleles. However it has not always been possible to assign susceptibility to individual genes because genes within the complex are in linkage disequilibrium. In this study, we tested DNA from sixty-three healthy controls and 64 Insulin Dependent Diabetes Mellitus: IDDM patients by Polymerase Chain Reaction-Sequence Specific Oligonucleotide: PCR-SSO, Polymerase Chain Reaction-Single Strand Conformation Polymorphism: PCR-SSCP analysis and DNA sequencing. These studies demonstrated the difference in frequencies of TAP2 gene products between healthy control and IDDM patient, and between Japanese and Caucasian population. Statistic analysis of HLA antigens and variants amino acids of TAP showed the linkage disequilibrium between TAP2-665, -687 sequence and HLA-DR alleles. The data suggests that the association of TAP2 allele with IDDM disease may be a simple reflection of the linkage disequilibrium between TAP allele and DR4 gene.

Antigen Presentation↗
PubMed1993

[Information system on cancer mortality and district characteristics of the Rhineland TUV].

On account of the lack of a comprehensive cancer registry with national coverage for the Federal Republic of Germany, the long-term and interregional evaluation of cancer mortality data is of particular relevance. Therefore, the TUV Rheinland instructed by the Federal Ministry for the Environment, Nature Protection, and Reactor Safety maintains an "Information System on Cancer Mortality and District Characteristics (IKK)" using official cause of death and resident population statistics. Mortality data for a variety of different cancer sites are documented with local and temporal separation for the area of the Federal Republic of Germany (before the German unification) and for a period of 20 years. The IKK data can be employed as a meaningful tool for epidemiological investigations relating to the correlation of cancer mortality and environmental agents. In the present paper the principles of the IKK are described and some examples of results are presented.

Adolescent↗
PubMed1995

Delivering health information databases on World Wide Web at the National University of Singapore.

The National University of Singapore (NUS) is one of the first medical schools in Asia to exploit the use of the World Wide Web on the Internet for the delivery of health information databases. Its WWW server was established in 1993 by the NUS Biocomputing Research and User Support (BRUS) technology group in collaboration with the Computer Resource Planning committee of the Faculty of Medicine. As a result of the early recognition of the powerful platform on which health information services can be delivered worldwide, the NUS effort has been accredited with a number of Internet firsts in the area of health informatics. The following are some of the NUS achievements: NUS-NCI CancerNet on the Web. The NUS developed and implemented the first WWW version of the popular CancerNet database offered by the National Cancer Institute, NIH, USA. Health Info-Com Network Medical Newsletter. The NUS developed and implemented the first WWW version of the medical newsletter, MEDNEWS which is edited by Dr. David Dodell, USA. It is now mirrored by the University of Pennsylvania in the United States and De Montfort University, U.K. Poisons Information Database. This first WWW implementation of a database on known plant, snake and other animal toxins with directories of antivenoms, toxinologists and poisons control centers around the world is offered by the NUS Venom and Toxin Research Group. HistoNet. This is a large collection of histology specimens from the NUS Department of Anatomy. MEDISTAT. This is the first WWW implementation of a Health and Population Statistical Database which contains information for Singapore, selected Asian countries and aggregate data for world regions. The Singapore Biotechnology Database. This database features companies and organizations involved in biotechnology and related activities in Singapore. Efforts are continuing to offer more value-added health information databases on the NUS WWW server and to link the server with other top-class information centers worldwide. Our mission is to identify the National University of Singapore as a global health information hub on the Internet.

Computer Communication Networks↗
PubMed1995

Neurodevelopmental test selection, administration, and performance in the main Seychelles child development study.

The Seychelles Child Development Study was designed to provide data on normal neurodevelopment of Seychellois children and to examine the relationship of their neurodevelopmental outcomes to in utero fetal exposure to low concentrations of methylmercury from a maternal diet high in fish. This paper outlines the strategies used to select, modify, and field test evaluation tools used in the main longitudinal prospective study of 740 children (95% of the cohort of 779 initially enrolled in 1989). It also gives population statistics and quality assurance data for the tests administered and the evaluation of the home environments.

Child↗
PubMed1996

[Diagnosis of uveitis with laboratory tests and specialized examinations].

The authors evaluated the importance of a large scale of laboratory examinations and specialized examinations in a group of 174 patients with endogenous uveitis examined at the uveological ambulance of the First Ophthalmological Clinic of the First Faculty, Charles University Prague. Laboratory examinations which are part of screening examinations are of little value for the diagnosis of uveitis. Alone they are unable to assess its type or prognosis. They cannot be recommended for routine work in the field. Only the incidence of phenotype HLA B27 in patients with anterior uveitis is, as compared with the healthy population, statistically significant (p < 0.005). Aimed collaboration with specialists from other disciplines is more important. The latter can on the basis of aimed examinations confirm or rule out systemic disease of a patient with uveitis suspected by the ophthalmologist.

Female↗
PubMed2002

A statistical test for the difference in the amounts of DNA variation between two populations.

A statistical test for the difference in the amounts of DNA variation between two populations is developed. The test statistic involves the covariance of the amount of variation between two populations, which is given by a function of their divergence time, T0. Accordingly, the power (rejection probability) of the test depends on T0. In this article, T0 is treated as unknown because it is very difficult to estimate. The test is most conservative when T0 = infinity is assumed because the covariance is zero. If T0 = 0 is assumed, the largest value of the rejection probability is obtained. Thus, the test provides a range of rejection probability unless we have a reliable estimate of T0. The test is applied to the PgiC region in three mustard species: Leavenworthia stylosa, L. crassa and L. uniflora. The results of our test show that the level of variation in L. stylosa is significantly higher than those in the other species.

DNA, Plant↗
PubMed2006

A tutorial on statistical methods for population association studies.

Although genetic association studies have been with us for many years, even for the simplest analyses there is little consensus on the most appropriate statistical procedures. Here I give an overview of statistical approaches to population association studies, including preliminary analyses (Hardy-Weinberg equilibrium testing, inference of phase and missing data, and SNP tagging), and single-SNP and multipoint tests for association. My goal is to outline the key methods with a brief discussion of problems (population structure and multiple testing), avenues for solutions and some ongoing developments.

Genetics, Medical↗
PubMed1990

Statistical assessment of population variability: a methodological approach.

We have implemented a multivariate statistical methodology to assess the degree and pattern of cranial variability in skeletal samples. Specifically, the method is designed to test whether variability in a skeletal sample exceeds "normal within-group variability" defined in the present instance as variability present among crania from a cemetery associated with a village. It involves comparing a covariance matrix derived from a sample of unknown composition to one representing "normal within-group variability." The method has been applied to two Plains Indian craniometric samples. The Leavenworth site (39CO9) represents the remnants of previously autonomous Arikara Indian villages devastated by epidemic diseases in the late 1700s. The Bad River 2 Phase is an archaeological designation grouping together closely related sites in the Bad-Cheyenne region of South Dakota dating from 1740-1795 AD. We were able to show substantial heterogeneity among crania from Leavenworth. District burial areas at Leavenworth account for some of the heterogeneity, supporting the notion that they represent an attempt to maintain former social distinctions. We were unable to differentiate among sites within the Bad River 2 Phase, suggesting that it is a valid biological unit.

Analysis of Variance↗
PubMed1997

[Statistic tests concerning population mortality indicators].

The objective of this note is to present simple statistical tests applied to common comparison problems met in descriptive studies in the general population. These tests apply to classical mortality indicators: crude and specific death rates, standardized rates (direct and indirect methods). The tests are based on the convergence of the Poisson distribution towards the normal distribution. For each type of comparison, confidence intervals are also provided.

Adult↗
PubMed2002

Statistical properties of population differentiation estimators under stepwise mutation in a finite island model.

Microsatellite loci mutate at an extremely high rate and are generally thought to evolve through a stepwise mutation model. Several differentiation statistics taking into account the particular mutation scheme of the microsatellite have been proposed. The most commonly used is R(ST) which is independent of the mutation rate under a generalized stepwise mutation model. F(ST) and R(ST) are commonly reported in the literature, but often differ widely. Here we compare their statistical performances using individual-based simulations of a finite island model. The simulations were run under different levels of gene flow, mutation rates, population number and sizes. In addition to the per locus statistical properties, we compare two ways of combining R(ST) over loci. Our simulations show that even under a strict stepwise mutation model, no statistic is best overall. All estimators suffer to different extents from large bias and variance. While R(ST) better reflects population differentiation in populations characterized by very low gene-exchange, F(ST) gives better estimates in cases of high levels of gene flow. The number of loci sampled (12, 24, or 96) has only a minor effect on the relative performance of the estimators under study. For all estimators there is a striking effect of the number of samples, with the differentiation estimates showing very odd distributions for two samples.

Computer Simulation↗