Biomedical subjects

T Wieser

Publications and source records attributed to T Wieser.

5 recordsLinked to original sources

PubMed1997

Ultrastructural alterations in the right and left ventricular myocardium following multiple low energy endocardial countershocks in anesthetized dogs.

Both high energy transthoracic and direct epicardial defibrillation can result in RV and LV myocardial damage, but little is known about the damage due to defibrillation using an endocardial RV electrode. Furthermore, disturbances in postdefibrillation oxidative metabolism have been reported and may be caused by primary injury of mitochondrial integrity and function, but information about ultrastructural mitochondrial alterations is rare. We therefore studied, in 13 fox hounds, RV and LV ultrastructural alterations following multiple low energy endocardial countershocks. Using an ICD and an endocardial defibrillation system a median of 54 (43-74) countershocks with a cumulative energy of 1,558 J (844-2,141 J) was delivered. After termination of countershocks, RV and LV myocardium was examined by electron microscopy. In both ventricles, severe myocardial alterations were found, including swollen mitochondria, disruption of mitochondrial crests, and loss of integrity of the mitochondrial inner and outer membranes. At the first time a semiquantitative score, originally developed for postischemic injury, was successfully used to grade the postcountershock mitochondrial alteration, which showed a more pronounced damage in the RV (2.69 +/- 0.22 points) compared to the LV (2.18 +/- 0.22 P = 0.021). We conclude that even the use of endocardial lead systems with low energy countershocks may lead to severe mitochondrial damage, especially in the RV.

Animals↗

PubMed1996

[Genetics of migraine].

Several historical reports focusing on the heredity of migraine, as well as recent studies on its epidemiology and molecular biology, have revealed evidence for a decisive role of genetic factors in the aetiopathogenesis of familial migraine. Indeed, family studies, segregation analyses and twin studies have shown that genetic factors play an important role in disposition towards migraine but could not explain the entire aetiopathogenesis. The influence of extragenetic factors, however, remains mostly unknown. Recent linkage analyses have provided evidence for genetic heterogeneity. A locus for Familial Hemiplegic Migraine (FHM), the only known type of migraine that follows autosomaldominant transmission, has been linked to chromosome 19p13 but genetic heterogeneity has also been shown, i.e., different types of migraine could be excluded from this locus. Further investigations should concentrate on identifying the FHM gene on chromosome 19p13, on linkage analyses with markers for different susceptibility genes, and on genomic analyses of highly informative pedigrees. This would lead to further clues to the pathogenesis underlying migraine and, thus, to therapeutic developments.

Chromosome Aberrations↗

PubMed1993

Mutation analysis in the diagnosis of cystic fibrosis.

Since the characterization of the gene encoding the cystic fibrosis transmembrane conductance regulator protein and identification of its main mutation, delta F508, causing cystic fibrosis (CF), more than 150 mutations in this gene have been reported, most of them only in a few or even single CF patients. Attempts to use mutation analysis in genetic counselling or for the diagnosis of CF depends on prevalence data of certain mutations in the respective population, and considerable ethnic differences have been reported. In this study we determined the prevalence of the mutations delta F508, G551D, R553X, and G542X and of genotypes defined by these mutations in 239 CF patients (444 independent CF chromosomes) seen in our clinic. The analysis for those four mutations alone now permits identification of approximately 75% of all mutations in our CF patients. The complete genotype can be resolved in approximately 63% of patients. This represents the diagnostic sensitivity which can be achieved by mutation analysis in patients without a family history of CF. We conclude that in situations where conventional diagnostic tests are not feasible or difficult to interpret, mutation analysis using a limited set of mutations can contribute significantly to an early and specific diagnosis of CF.

Adolescent↗

PubMed1987

[Sex specific factors in recurrent idiopathic calcium urolithiasis].

For question of sex dependency 24 h-urine samples of 165 patients with recurrent idiopathic calcium urolithiasis (100 men, 65 women) were obtained during regular diet and analyzed for differences in excretion rates of lithogenic and inhibitory constituents. Results were compared to values of 43 apparently healthy subjects (31 men, 12 women). Male stone patients revealed significantly higher excretion rates of lithogenic substances (calcium, uric acid, phosphate) and of the inhibitory agent magnesium than female patients. No differences were found for citrate and oxalate excretion values. Combination of an elevated rate of hyperuricosuria and significantly lower urine-pH in male patients results in a higher risk of stone formation in men. Similar differences between sexes were observed among controls but on a lower excretory level. Trying to explain the differing urinary excretion rates between sexes, the influence of sex differences in diet and body weight is discussed. An alteration of stone forming risk through action of sex hormones on urinary constitution appears unlikely.

Adult↗

PubMed1969

[Gentamycin].

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Ampicillin↗