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Biomedical subjects

H Walter

Publications and source records attributed to H Walter.

At least 433 records · Page 24Linked to original sources

Factors involved in capillary growth in the heart.

Growth of capillaries in the heart occurs under physiological circumstances during endurance exercise training, exposure to high altitude and/or cold, and changes in cardiac metabolism or heart rate elicited by modification of thyroid hormone levels. Capillary growth in all these conditions can be linked with increased coronary blood flow, decreased heart rate, or both. This paper brings evidence that, although increased blood flow due to long-term administration of coronary vasodilators results in capillary growth, a long-term decrease in heart rate induced by electrical bradycardial pacing in rabbits and pigs, or by chronic administration of a bradycardic drug, alinidine, in rats, stimulates capillary growth with little or no change in coronary blood flow. Decreased heart rate results in increased capillary wall tension, increased end-diastolic volume and increased force of contraction, and thus stretch of the capillary wall. This could lead to release of various growth factors possibly stored in the capillary basement membrane. Correlation was found between capillary density (CD) and the levels of low molecular endothelial cell stimulating angiogenic factor (ESAF) both in rabbit and pig hearts with CD increased by pacing. There was no relation between expression of mRNA for basic fibroblast growth factor and CD in sham-operated and paced rabbit hearts. In contrast, mRNA for TGF beta was increased in paced hearts, and the possible role of this factor in the regulation of capillary growth induced by bradycardia is discussed.

Angiogenesis Inducing Agents↗

Dopamine and alcohol relapse: D1 and D2 antagonists increase relapse rates in animal studies and in clinical trials.

A considerable number of animal studies on the effects of dopaminergic agents on alcohol intake behavior have been performed. Acute alcohol administration in rats induces dopamine release in the caudate nucleus and in the nucleus accumbens, an effect related among others to reinforcement. It has been repeatedly suggested that D1 and D2 receptor activation mediates reward. As alcohol consumption and dopaminergic transmission seem to have a close relationship, all kinds of dopaminergic agents may be regarded as putative therapeutics for preventing relapse. In a prospective European double-blind multicenter clinical trial, comparing the D1, D2, D3 antagonist flupenthixol and placebo in 281 chronic alcohol-dependent patients (27.4% women), the application of the Lesch typology made an outcome differentiation possible. It could be shown in which patients flupenthixol administration was followed by a significantly higher relapse rate and in which patient groups no differences were found when compared to placebo.

Alcoholism↗

The European acamprosate trials: conclusions for research and therapy.

In an excellent methodological approach, the European acamprosate study project showed that acamprosate increases sobriety times. In one randomized prospective study (n = 260) comparing acamprosate and placebo, with a 1-year treatment phase and 1-year follow-up phase, the authors found that acamprosate is effective only in Lesch type I and type II patients. To investigate the possible influence of diagnostic subgrouping, we applied the Lesch typology in a co-work with the main researchers of the UK study. The UK results concerning acamprosate's effects in the types do not mirror the Vienna results, but the numbers of type I and type II patients, retrospectively found as included in the UK centers, were too small for any conclusions. The distribution of the types points to the fact that too many type III and IV patients had been included to give acamprosate the chance to be effective. Following our typology and also these studies, we developed special treatment approaches. For relapse prevention studies, the cumulative abstinence duration together with the Lesch typology seems to be promising.

Acamprosate↗

Effect of prolonged optimal blood sugar control by i.v. insulin administration on plasma free fatty acid and glycerol concentrations of insulin-dependent diabetics during exercise.

Four type I diabetics were kept close to normoglycemic during a period of 1 month by means of a an open loop i.v. insulin infusion system (Siemens). During submaximal physical exercise their metabolic response was nearly normal. No hypoglycemic episodes during exercise were registered despite the fact that the regular basal infusion rate was not changed. The level of free fatty acids rose approximately to the same extent as in normal subjects. A slight inhibition of lipolysis during i.v. insulin therapy was apparent from the less marked rise of the glycerol levels. The feasibility of a simple open loop i.v. insulin regimen over a prolonged period of time is underscored by these results which show that the basal insulin infusion rate can be kept constant during exercise.

Adult↗

Regional brain function in hallucinations: a study of regional cerebral blood flow with 99m-Tc-HMPAO-SPECT in patients with auditory hallucinations, tactile hallucinations, and normal controls.

From the supposition that there exists a possible connection between certain psychopathological symptoms, and/or syndromes (e.g., hallucinations) and regional cerebral dysfunction, patients suffering from auditory and tactile hallucinations were investigated, in a symptom-oriented study, using the method of technetium-99m-Hexamethyl-propylenamine Oxime (99m-Tc-HMPAO)-Single Photon Emission Computed Tomography (SPECT) and compared with normal controls. The results support Jackson's hypothesis to the effect that hallucinatory phenomena will primarily occur when the normally inhibitive influence of the upper cortical centers over the lower brain structures diminishes, resulting in relative hyperactivity in the basal regions. In addition to the brain activity-changes generally observed in hallucinating patients, it was possible to identify regional cerebral blood flow (rCBF)-distribution patterns characteristic in certain forms of hallucinatory phenomena, i.e., a significant increase of activity in the hippocampal regions (including hippocampus, parahippocampus, and amygdala) only in patients with auditory hallucinations, and a significant reduction of rCBF in the inferior temporal regions in patients with tactile hallucinations.

Adult↗

Gender differences in emotional disability and negative health perception in cardiac patients 6 months after stent implantation.

OBJECTIVES: In this study we evaluate gender differences in affective adaptation and health perception in patients 6 months after stent implantation. BACKGROUND: Assessment of gender-specific behavioral strategies to cope with serious cardiac disease conditions has not been given much attention until now. Preliminary data suggest greater impairments in female patients, which might be of clinical relevance. METHODS: Three hundred seventeen patients were eligible for the 6-month follow-up investigation, 78 (24.6%) of whom were women. The women were significantly older but did not differ from men in their cardiac risk features and treatment procedures. There were no gender differences in prevalence of hypertension, hypercholesterolemia, and family history. Men had a significantly higher prevalence of smoking than women, whereas women had a significantly higher prevalence of diabetes than men. A structured interview and a standardized psychodiagnostic assessment was carried out, which covered domains of affective dysfunction (depression, anxiety, intrusion, and avoidance), vegetative symptoms (sleeping disorders), and parameters of negative health perception. RESULTS: There were no significant gender differences in the prevalence of depressive symptoms. Women exhibited higher mean values of anxiety than men, which did not reach significance. Sleeping disorders were significantly more prevalent in women. The absolute level of being distressed by intrusive thoughts and avoidance behavior related to the severe underlying disease process was low in the total group of patients examined. Measurable gender differences did not emerge. Fifty-one (16.5%) patients exhibited pessimistic anticipation of dire consequences and severe signs of negative health perception (NHP group). There was a trend, although not statistically significant, toward more women being in the NHP group. The distribution of cardiac risk factors, however, was completely balanced in the NHP(+) and NHP(-) patient groups. Objective somatic cardiac disease parameters did not account for the negative health perception. NHP was, however, associated with significantly more prestent angina pectoris (p < 0.040) and poststent angina pectoris (p < 0.0001). High levels of anxiety, depression, and of disturbed sleep also led to a sharp separation between patients with high degrees of an anticipated incapacitation due to the disease process. Univariate regression analysis suggested an effect of female gender on the occurrence of NHP (odds ratio 1. 70; 95% CI 0.88 to 3.25), which was of borderline significance. Control for confounders in a multiple regression model, however, eliminated the gender effect (odds ratio 1.04, 95% CI 0.48 to 2.23). Poststent chest pain (odds ratio 7.75, 95% CI 3.28 to 18.32) and sleeping disorders (odds ratio 1.32, 95% CI 1.16 to 1.51) were identified as the most powerful confounders of the gender-NHP association. CONCLUSION: Contrary to expectation, women were not per se more distressed than men in all areas of adaptation of the midterm course after stent implantation, although the higher levels of anxiety and sleeping disorders in women deserve attention. A considerable proportion of patients exhibited a pessimistic disease perspective independent of their somatic status, which was associated with affective morbidity. The tendency toward more negative health perception in women may be due to their more frequent occurrence of chest pain and sleeping disorders.

Adaptation, Psychological↗

Genetic studies in four tribal populations of the Surat District, Gujarat (India).

Four tribal populations (Chaudhuri, Vasava, Kotwalia and Gamit) of the Surat District in Gujarat (India) have been investigated for the distribution of 22 polymorphic systems of the blood. The main results of this study are as follows: The allele frequencies show considerable heterogeneity among these populations. From the genetic structure analysis it is seen that only a small fraction of the total gene diversity accounts for genetic differences among them, and the major portion of it is due to genetic variation within them. Analysis of genetic distance according to Nei (1972) reveals that the Vasava and Kotwalia show a rather close genetic relationship, while the Chaudhuri and Gamit differ from both the Vasava and Kotwalia.

Blood Group Antigens↗

Immunoglobulin (Gm and Km) allotypes in nine endogamous groups of West Bengal, India.

Blood samples from 898 individuals of nine endogamous groups of West Bengal, India were typed for determining the haplotypic structure in the gamma-light chain (Gm) and kappa-light chain (Km) of immunoglobulin (IgG). The Gm haplotype frequencies detected by Glm (1), Glm (2) and G3m (5) markers suggest that in this eastern state of India there is considerable variation of frequencies of the typical Mongoloid haplotype Gm1,5, which shows a high incidence in Rajbanshi, Rabha, Garo and Lodha groups. On the contrary, this haplotype is probably absent in the high caste groups, Rarhi Brahmin and Vaidya, and is relatively infrequent in Jalia Kaibarta, a scheduled caste of the south-western part of the state. The Km1 allele is also high in frequency among Rajbanshi, Rabha, Garo and Munda in comparison with Rarhi Brahmin and Vaidya, suggesting the former four groups' strong Mongoloid affiliation. This survey signifies that there is considerable variation in the extent of Mongoloid admixture in Bengali populations. Such admixture is not restricted in specific social class either. It further demonstrates that heterogeneity of the genetic structure of Bengali populations do not correspond to the present social ranking on the basis of caste hierarchy.

Asian People↗

Serum protein polymorphisms (HP, TF, GC and PI) in four Iranian population samples.

A total of 960 individuals from four Iranian population samples (Tabriz, Tehran, Yazd, Mashhad) was typed for HP and for TF, GC and PI subtype polymorphism. Statistically significant intergroup heterogeneity in the distribution of allele frequencies was found only in the HP polymorphism. Comparisons with other Iranian populations suggest considerable ethnic differences with regard to the TF and GC subtype polymorphisms. Some rare alleles were observed in all four samples (Tabriz: GC*1C1; Tehran: PI*S: Yazd: PI*S; Mashhad: PI*Z).

Blood Proteins↗

GM and KM allotypes in nine population samples of Sicily.

Serum samples of 864 unrelated healthy male and female individuals belonging to nine provinces of Sicily were types for Glm (1,2,3,17), G3m (5,10,11,13,14,15,16,21), and KM (1). With the exception of the Trapani sample these samples are characterized by the presence of five GM haplotypes: GM*1,17;21,26; GM*1,2,17;21,26; GM*1,3;5,10,11,13,14,26; GM*3;5,10,13,14,26; and GM*1,17;10,11,13,15,16. The interpopulation variability in the distribution of these haplotypes is considerable, which is especially due to haplotypes GM*1,3;5,10,11,13,14,26, and GM*3;5,10,13,14,26. However, no clear-cut clustering of the samples according to historical or geographical facts could be shown. Comparisons with other Italian populations reveal the considerable genetic difference of the Sicilians, which is in particular caused by the presence of the haplotypes GM*1,3;5,10,11,13,14,26, and GM*1,17;10,11,13,15,16. These haplotypes are quite uncommon in Europeans and may reflect gene flow from the Middle East. The KM phenotype and allele frequencies also show a considerable interpopulation variability among the nine Sicilian samples, but as for GM no distinction between eastern and western provinces of Sicily is present.

Adult↗

Psychophysiological diagnostics in alcohol dependency: Fourier analysis of pupillary oscillations and the receptor test for determination of cholinergic deficiency.

Mnestic disturbances in alcoholics may be related to cholinergic deficiency as well as to central nervous system inactivation. After instillation of tropicamide, cholinergic receptors are blocked and pupillary dilatation occurs. It is assumed that the more severe the cognitive deterioration, the wider the pupillary dilatation. Pupillary oscillations reflect central activation. Changes of pupillary diameter after topical instillation of tropicamide and pupillary oscillations were measured in 44 alcohol-dependent patients aged 40-55 years, diagnosed according to the DSM-III-R as severe alcoholics (>7 symptoms), having been abstinent for at least 3 weeks (objectively tested with carbohydrate-deficient transferrin), compared with 18 healthy controls. The pupillary diameter of the left eye was measured eight times within 103 min, as were pupillary oscillations. Using Fourier analysis, the amplitudes of oscillations were measured in five frequency bands and the sum of the frequency bands was calculated. In addition, central activation was measured during a calculation test at 3 and 103 min. The pupillary dilatation of 22% in alcoholics compared to 14% of normal controls after tropicamide raises the question of a cholinergic deficit in alcohol dependence. With regard to basic activation, measured by Fourier analysis of pupillary oscillations, alcoholics demonstrated significantly lower power (sum of the frequency bands) than controls at baseline and at 3, 20, and 40 min (P < 0.01) as well as at 60, 80, 100, and 103 min (P < 0.05). After a cognitive task, a difference between alcoholics and healthy controls was found at 3 min. Alcoholics showed lower basic activation and decreased cognitive activation. By means of cross-validation, a differentiation between alcohol-dependent patients (n = 44 and n = 42 respectively) and normal controls (n = 18) was possible.

Adult↗