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Biomedical subjects

L Thaler

Publications and source records attributed to L Thaler.

16 recordsLinked to original sources
PubMed1999

Declining bone mass in men with chronic pulmonary disease: contribution of glucocorticoid treatment, body mass index, and gonadal function.

BACKGROUND: Men with chronic lung disease (CLD) are at risk for osteoporosis, but the relative contributions of their chronic pulmonary disease, glucocorticoid therapy, and other factors toward loss of bone has not been established. Understanding the relative importance of these factors would assist in selecting patients for bone densitometry screening and in policy decisions regarding Medicare reimbursement. OBJECTIVE: To identify patients with CLD who are most likely to benefit from bone densitometry screening based on clinical and biochemical measures. DESIGN: Cross-sectional medical survey. PATIENTS: Patients with CLD who were treated with either oral, inhaled, or no glucocorticoid therapy. A control group without lung disease was recruited from the same clinic population. MEASUREMENTS: Dual-energy X-ray absorptiometry was obtained for each group, and the association between bone mass and clinical variables, glucocorticoid use, gonadal hormones, and biochemical markers of bone metabolism was determined. RESULTS: Osteoporosis (a T score < -2.5 at the hip or spine) was five times as likely in patients with CLD as in control subjects. Although the prevalence of osteoporosis was higher (ninefold) after chronic glucocorticoid therapy, patients with CLD who had never been treated with glucocorticoids had a substantial (fourfold) risk of osteoporosis. Chronic inhaled glucocorticoid therapy offered no protection from bone loss compared to treatment with oral glucocorticoids. Of the clinical and biochemical measures that were obtained, bone mass was weakly correlated with body mass index (BMI), serum estradiol-17beta, and N-telopeptide, but not with testosterone, alkaline phosphatase, bone-specific alkaline phosphatase, or osteocalcin. CONCLUSION: Patients with CLD should be considered for bone densitometry screening regardless of glucocorticoid use. Those patients with a low BMI and/or decreased serum estradiol-17beta comprise a subgroup with increased risk for osteoporosis.

Adult↗
PubMed1993

Effect of withdrawal of antihypertensive drug on depressive mood.

To evaluate the effects on depressive mood of withdrawal of antihypertensive medication, we conducted a randomized, multi-center study with clinical centers at the Albert Einstein College of Medicine, Bronx, NY, University of Alabama School of Medicine, Birmingham, and the University of Mississippi School of Medicine in Jackson. Patients were formerly active participants in the Hypertension Detection and Follow-Up Program (HDFP) whose blood pressure was controlled with drugs for a period of 5 years. Of 496 patients, 431 had both baseline and "1-year" mood scores. Patients, stratified by obesity, were randomized to one of three groups: continue the HDFP medication; discontinue medication with no dietary intervention, or with sodium restriction and potassium increase; or, for those overweight, to a weight reduction intervention. Depression was assessed using the CES-D scale (Center for Epidemiological Studies--Depressed Mood), administered at baseline and again approximately 1 year after randomization. Of the seven treatment groups, only those who continued their HDFP medication showed significant improvement in mood from baseline. The overweight continue-medication group showed significantly greater improvement compared to the no-drugs, no-diet intervention groups, and to the overweight sodium-restriction group. Patients who had their blood pressure successfully controlled with weight reduction had a significant improvement in mood from 11.0 scale points to 8.0, P = .006. Comparisons between those withdrawn from diuretic alone and those withdrawn from both diuretic plus reserpine were inconclusive. Dietary Intervention Study of Hypertension (DISH) shows no evidence that continued use of chlorthalidone has a negative impact on quality of life, while our results concerning reserpine were inconclusive.(ABSTRACT TRUNCATED AT 250 WORDS)

Affect↗
PubMed1989

Genic differentiation and origin of Robertsonian populations of the house mouse (Mus musculus domesticus Rutty).

This paper examines the relation between chromosomal and nuclear-gene divergence in 28 wild populations of the house mouse semi-species, Mus musculus domesticus, in Western Europe and North Africa. Besides describing the karyotypes of 15 of these populations and comparing them to those of 13 populations for which such information was already known, it reports the results of an electrophoretic survey of proteins encoded by 34 nuclear loci in all 28 populations. Karyotypic variation in this taxon involves only centric (or Robertsonian) fusions which often differ in arm combination and number between chromosomal races. The electrophoretic analysis showed that the amount of genic variation within Robertsonian (Rb) populations was similar to that for all-acrocentric populations, i.e. bearing the standard karyotype. Moreover, divergence between the two types of populations was extremely low. These results imply that centric fusions in mice have not modified either the level or the nature of genic variability. The genetic similarity between Rb and all-acrocentric populations is not attributed to the persistence of gene flow, since multiple fusions cause marked reproductive isolation. Rather, we attribute this extreme similarity to the very recent origin of chromosomal races in Europe. Furthermore, genic diversity measures suggest that geographically separated Rb populations have in situ and independent origins. Thus, Rb translocations are probably not unique events, but originated repeatedly. Two models are presented to explain how the rapid fixation of a series of chromosomal rearrangements can occur in a population without lowering variability in the nuclear genes. The first model assumes that chromosomal mutation rates are between 10(-3) and 10(-4) and that populations underwent a series of transient bottlenecks in which the effective population size did not fall below 35. In the second model, genic variability is restored following severe bottlenecks, through gene flow and recombination.

Animals↗
PubMed1988

H-2 polymorphisms are more uniformly distributed than allozyme polymorphisms in natural populations of house mice.

Patterns of H-2 and allozyme polymorphism in natural populations of house mice from Europe, North Africa and South America were analyzed. The purpose of the analysis was to determine whether H-2 and allozyme polymorphisms were similarly distributed both geographically and temporally in wild mice. Two subspecies of house mice, Mus musculus domesticus and M. m. musculus were sampled and the polymorphisms of two H-2 class I genes, H-2K and H-2D, and 34 allozyme-encoding genes were surveyed. The three kinds of analyses that were conducted included a hierarchical gene diversity analysis, an analysis of the effects of barriers to gene flow, and an analysis of similarity networks. Each of the comparisons demonstrated that H-2 polymorphisms were more uniformly distributed than allozyme polymorphisms and provided additional evidence that H-2 and allozyme polymorphisms are subject to different evolutionary pressures. The analysis of similarity networks also demonstrated that H-2 genes provide little information about the phylogeny of wild mice.

Animals↗
PubMed1988

[Genetic analysis of the hybridization zone between two subspecies Mus musculus domesticus and Mus musculus musculus in Bulgaria].

The hybrid zone between the two subspecies of mice Mus musculus domesticus and Mus musculus musculus, which has been studied extensively in Denmark, crosses Europe to the Black Sea through the Alps and the Balkans. Two hundred and seventy-nine animals were captured in 22 localities along a transect across the Balkans. The animals were characterized for seven diagnostic nuclear loci by protein electrophoresis and by restriction pattern analysis of their mitochondrial DNA. The nuclear data show a sharp transition between the two subspecies, most of the variations in allele frequencies (from 0.9 to 0.1) occurring within a 36-km section of the transect. The introgression varies from one locus to the other and is more pronounced, in terms of distance, in M. m. musculus territory. Mitochondrial DNA introgression is important but occurs in one direction only, i.e. from M. m. musculus to M. m. domesticus, while a cytoplasmic transfer from M. m. domesticus to M. m. musculus has been reported. A previous study showed that no Y chromosome introgression occurs. The different behaviour of these three types of markers could be due to the interaction between selection against hybrid genomes and meiotic recombination. Objectively, it would appear that the genes that can introgress are neutral or nearly so and have been separated from deleterious genes they were linked to by recombination. This could explain the differential introgression between autosomal loci. The mitochondrial and Y chromosomes undergo no or very little recombination and each is transmitted as a whole. Their degree of introgression is thus indicative of the intensity of selection resulting from the amount of functional differentiation between the two taxa, which seems to be strong for the Y chromosome and weak for mitochondrial DNA. We propose that the asymmetry of nuclear introgression is due to different population structures. As M. m. musculus is relatively less structured, the rapid spreading of introgressed genes would be favoured. Such a scheme, however, can hardly account for the unidirectionality of the mitochondrial flow, which could be due to sex-dependent behaviour.

Alleles↗
PubMed1984

Biochemical diversity and evolution in the genus Mus.

Thirteen biochemical groups of wild mice from Europe, Asia, and Africa belonging to the genus Mus are analyzed at 22-42 protein loci. Phylogenetic trees are proposed and patterns of biochemical evolution are discussed, as well as the possible contribution of wild mice to the genetic diversity of laboratory stocks.

Alleles↗
PubMed1981

[Not Available].

Explore the source record for details and available documents.

Biological Evolution↗
PubMed1978

[The existence in Europe of four groups of mice (genus Mus L.) of species and subspecies rank, demonstrated by biochemical genetics].

Analysis at 20 genetic loci by starch gel electrophoresis of a population from Greece shows that contrary to most accepted views, the outdoor Eastern Mediterranean Short-tailed Mouse (i) does not belong to the same species as the House Mouse (Mus musculus), (ii) is not less distant from the Eastern European semi-species of House Mouse (biochemical group 2) than from the Western and Mediterranean European semi-species (group 1), and (iii) is not more closely related to the outdoor Western Mediterranean Short-tailed Mouse Mus spretus (group 3), than to M. musculus. It represents a new biochemical group (group 4) and deserves a species rank (Mus spicilegus).

Alleles↗
PubMed1978

[Hybridization between Mus musculus L. and Mus spretus Lataste under laboratory conditions (author's transl)].

2 species of mice Mus musculus brevirostris and Mus spretus are sympatric in Southern France and reproductively isolated. However, under laboratory conditions, they breed and give fully viable F 1 hybrids. This indicates that premating isolating mechanisms probably occur in nature and have yet to be investigated. Moreover, it now enables us to introduce new genetical markers in laboratory strains.

Animals↗
PubMed1978

Evidence for the presence of two sympatric species of mice (genus Mus L.) in southern France based on biochemical genetics.

Populations of mice established outdoors as well as indoors have been investigated at 24 loci using starch gel electrophoresis. Two reproductively isolated groups are recognized, one of which is referable to a house mouse subspecies, Mus musculus brevirostris, and the other to a different species. Mus spretus, contrary to the view of Schwarz and Schwarz that only one species of Mus is present in the Mediterranean Basin. The genetic distance between these two groups is larger than between any pair of investigated subspecies of M. musculus. M. m. brevirostris is biochemically almost indistinguishable from M. m. domesticus. On the other hand, M. spretus exhibits several allelic variants unknown or at most very infrequent in M. musculus, as for instance at the lactate dehydrogenase B-chain locus.

Animals↗
PubMed1976

[Mice of southern France: genetic characterization of two groups of sympatric populations].

An electrophoretic survey of five proteins (lactate dehydrogenase, isocitrate dehydrogenase, esterase-1, esterase-2, albumin) shows that there are two groups of populations strongly (or completely) reproductively isolated. The first group does not differ from Mus musculus L. The second exhibits several new biochemical traits and should probably be considered a different species.

Animals↗