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Biomedical subjects

U Schmidt

Publications and source records attributed to U Schmidt.

At least 217 records · Page 12Linked to original sources
PubMed1993

[St. John's wort extract in the ambulatory therapy of depression. Attention and reaction ability are preserved].

METHOD: In a placebo-controlled, randomized, double-blind trial involving outpatients with mild to moderately severe depression, an extract of St. John's wort (Hypericum), LI 160, a herbal antidepressant was tested for efficacy and tolerability, as well as for possible negative effects on cognitive performance. RESULTS: The responder rate to treatment with the extract was 66.6% as compared with only 26.7% with placebo. The treatment was very well tolerated; only in two patients did transient minor side effects occur under LI 160. No impairment of cognitive performance was observed: during the trial, Hypericum did not lead to any impairment of attention, concentration or reaction.

Adult↗
PubMed1993

[The elderly in street traffic--effect of drugs].

For the medical assessment and treatment of the elderly, both general and disease-induced deterioration in performance, in particular of the cognitive functions, has to be taken into consideration. Treatment with drugs must take account not only of the altered pharmacokinetics and pharmacodynamics in the elderly, but also of possible drug-induced impairment of driving ability--which is already affected by physiological changes. Medical treatment of sick elderly drivers should be restricted to low-risk, well-proven and absolutely necessary medication. Studies on a sample of elderly drivers with diminished cognitive performance show that problem-specific drug treatment improves driving ability rather than impairing it.

Accidents, Traffic↗
PubMed1993

Self-splicing of a Podospora anserina group IIA intron in vitro. Effects of 3'-terminal intron alterations on cleavage at the 5' and 3' splice site.

A shortened derivative of the group IIA intron from the mitochondrial cytochrome-c-oxidase subunit I gene (COI I1) of the ascomycete Podospora anserina can undergo self-splicing in vitro. When compared to self-splicing group IIB introns from yeast mitochondria (aI5c, bI1) the autocatalytic reaction shows a lower efficiency and 5' cleavage takes place predominantly by hydrolysis. In order to test the influence on reaction efficiency and mode of 5' cleavage of the long peripheral structure of domain VI (dVI) we generated mutant Podospora introns that have different structural forms of shortened dVI. Our results show that: (1) in general the size and structure of dVI distal from the branch site is essential for 5' transesterification and influences the efficiency of the second splicing step; (2) 5' transesterification as well as the complete self-splicing reaction is more efficient when the structure of dVI is adapted to that of yeast group IIB introns. Moreover, our data indicate that the postulated gamma-gamma' tertiary interaction is also functional for group IIA introns. A weakening or disruption of this interaction in the Podospora intron leads to a greatly reduced cleavage at the 3' splice site and to a selection of cryptic sites downstream in the 3' exon that almost exclusively restore the strong wild-type gamma-gamma' pairing. The so-called "guide" interaction seems to support the selection of 3' cleavage sites but is of secondary importance in relation to the gamma-gamma' interaction.

Ascomycota↗
PubMed1993

Self-treatment of bulimia nervosa: a pilot study.

Twenty-eight patients with ICD-10 bulimia nervosa or atypical bulimia nervosa were given a cognitive-behavioral treatment handbook and were reassessed 4-6 weeks later. On a clinician-rated global improvement scale 12 patients had much improved and 8 patients had somewhat improved. Fifteen patients were abstinent of vomiting or laxatives at reassessment as opposed to five patients before treatment. Of the 21 patients who were bringing before treatment, 7 had a 75-100% reduction of binges and 5 had a 50-75% reduction of binges. Patients' nutritional knowledge increased significantly. A patient-administered hand-book may be a useful first intervention in the treatment of patients with bulimia nervosa.

Adult↗
PubMed1993

Bulimia nervosa in the Chinese.

Typical DSM-III-R bulimia nervosa with self-induced vomiting was found in 2 women of Hong Kong Chinese origin and a Chinese man from Malaysia. All 3 cases had a family history of obesity. In 2 of the cases a period of weight gain and in the third case frank obesity preceded the onset of the eating disorder. Cultural transition seemed to play an important part in the onset and maintenance of the eating disorder.

Adult↗
PubMed1993

Myocardial scintigraphy with thallium-201 and technetium-99m-hexakis-methoxyisobutylisonitrile in left bundle branch block: a study in patients with and without coronary artery disease.

In left bundle branch block (LBBB) thallium-201 myocardial scintigraphy frequently reveals septal abnormalities in the absence of coronary artery disease (CAD) and gives rise to "false-positive" results in patients with suspected CAD. It has not yet been clarified which pathophysiological mechanism is responsible for these perfusion abnormalities. A total of 66 patients with constant LBBB were investigated with 201Tl or technetium-99m-hexakis-methoxyisobutylisonitrile (MIBI), 62 underwent coronary angiography. Of 12 patients without left anterior descending artery (LAD) or right coronary artery (RCA) stenoses, 11 had a reversible septal activity deficit after 201Tl stress injection, whereas 20 of 22 patients without relevant CAD showed a constant stress/rest septal deficit using MIBI. Regarding patients with significant LAD and/or RCA stenoses, both radio-pharmaceuticals almost always showed a "reversible" septal deficit: with 201Tl in 15 of 16 individuals and with MIBI in 14 of 15. In 12 patients 201Tl was reinjected at rest. In those who had LAD or RCA stenoses (n = 5), early septal activity uptake after stress injection was poorer than that after rest injection; in the absence of CAD (n = 7), septal stress uptake corresponded with that of rest injection. It is concluded that septal perfusion abnormalities in LBBB and the absence of CAD are characterized by an exercise-independent reduction of septal blood flow per mass of viable myocardium and that stress/rest injection protocols of myocardial perfusion tracers are able to differentiate between LBBB with and without CAD.

Aged↗
PubMed1993

Setting the scene for eating disorders: childhood care, classification and course of illness.

The aim of this study was to determine whether the childhood experiences of patients with anorexia nervosa and bulimia nervosa differ and affect the course of the illness. A semistructured interview developed by Harris et al. (1986) was used to assess the childhood family environment of 64 patients with restricting anorexia nervosa (RAN), 23 patients with bulimic anorexia nervosa (BAN), 37 bulimic patients with a history of anorexia nervosa (BN/HistAN) and 79 patients with normal weight bulimia nervosa (BN). There were no significant differences between groups in terms of parental mental disorder, low parental control or childhood sexual abuse. BN patients had had significantly more family arrangements and had experienced more parental indifference, excessive parental control, physical abuse, and violence against other family members than RAN patients with the BAN and BN/HistAN group being intermediate. There was a trend for BN-patients to have had more intra-familial discord than the other groups. Different aspects of adversity tended to cluster in the same patients and 65% of the bulimic group had experienced two or more types of childhood adversity. These results suggest that childhood experiences contribute to the form of eating disorder which later develops.

Adult↗
PubMed1993

Evidence for an interaction of halothane with the L-type Ca2+ channel in human myocardium.

BACKGROUND: The present study was aimed at investigating the underlying mechanisms for the cardiac depressant effect of halothane. To test the hypothesis, whether there is an interaction of halothane with the L-type Ca2+ channels in human myocardium and whether this interaction has functional consequences for force generation in the human myocardium, effects of halothane were studied in human myocardial membranes and isolated cardiac preparations. METHODS: The experiments were performed on isolated, electrically driven ventricular preparations (1 Hz, 37 degrees C) and cardiac membranes with radioligand binding experiments using 3H-PN 200-110. Myocardium from human failing and non-failing hearts was obtained at cardiac surgery. RESULTS: Halothane produced a negative inotropic effect, which was similar in nonfailing and failing myocardium. Halothane shifted the concentration-response curve for the positive inotropic effect of the L-type Ca2+ channel agonist BayK 8644 to the right. The density of dihydropyridine receptors as judged from 3H-PN 200-110 radioligand binding experiments was similar in nonfailing and failing myocardium, whereas the density of beta-adrenoceptors was reduced. Halothane concentration dependently reduced the binding of 3H-PN 200-110, an antagonist at the 1,4 dihydropyridine receptor site of the Ca2+ channel, to myocardial membranes. Furthermore, halothane produced a rightward shift of the competition curve of BayK 8644 for binding of 3H-PN 200-110 to cardiac membranes. CONCLUSIONS: In human ventricular myocardium, halothane exhibits an interaction with the L-type Ca2+ channel by interfering with its dihydropyridine binding sites. This may explain, at least in part, the observed negative inotropic effect of this agent and could hypothetically play a general role in its anesthetic effects.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Effects of halothane on beta-adrenoceptors and M-cholinoceptors in human myocardium: radioligand binding and functional studies.

We investigated whether a postsynaptic sensitization by halothane for beta-adrenoceptor-mediated effects occurs in diseased human myocardium. In addition, we hoped to achieve further insights into the cellular mechanism and, in particular, the role of M-cholinoceptors and beta-adrenoceptors. The experiments were performed on isolated, electrically driven atrial and ventricular preparations and membranes isolated from human hearts obtained at cardiac surgery. Halothane concentration-dependently reduced binding of [3H]quinuclidinylbenzilate ([3H]QNB) to M-cholinoceptors but had no effect on equilibrium saturation binding of 125-iodocyanopindolol (125I]Cyp) to beta-adrenoceptors. High-and low-affinity states of agonist binding of carbachol to M-cholinoceptors were not affected, but halothane inhibited high-affinity binding of isoprenaline to beta-adrenoceptors. In contrast, halothane augmented the potency and efficacy of the positive inotropic effect of isoprenaline in atrial and ventricular myocardium. The "direct" negative inotropic effect in atrial and the "indirect" negative inotropic effect in ventricular myocardium by M-cholinoceptor stimulation with carbachol was unchanged by halothane. We conclude that in human atrial and ventricular myocardium a sensitization to catecholamines is induced by halothane, the mechanism of which is likely to be located at the postsynaptic level of the sympathetic neuroeffector junction. Facilitated coupling of beta-adrenoceptors or an uncoupling of M-cholinoceptors with reduced negative inotropic effects of agonist does not play a role. We showed that sensitization of this system apparently is due to direct actions of halothane on the G-protein-coupled adenylate cyclase complex.

Catecholamines↗
PubMed1993

The effect of exogenous melatonin on the hypothalamic-pituitary-adrenal axis in intact and pinealectomized rats under basal and stressed conditions.

The effect of exogenous melatonin on the adrenocortical axis was studied by determining serum corticosteroid and adrenocorticotrophic hormone (ACTH) levels under basal and stressed conditions in intact, pinealectomized, and adrenalectomized mature male rats. A direct interrelationship between pineal/melatonin and the adrenal cortex, dissociated from the hypothalamic-pituitary axis, was established. Intraperitoneal injection of 100 micrograms melatonin brought about an elevated adrenocortical response recorded in the serum corticosteroid levels 15 hr afterwards. This effect could be demonstrated only at the beginning of the photophase, when physiological levels of corticosteroids and ACTH are at their lowest daily levels. The pattern of this reaction is different from those caused by stressors such as ether or hypoglycemic reagents, and did not occur in pinealectomized animals although the daily rhythm of corticosteroids and ACTH persisted. No effect on ACTH was evident in intact or adrenalectomized rats, where the serum levels remained unchanged. Moreover, the corticotrophin releasing factor (CRF) content of the median eminence was not affected by melatonin.

Adrenal Cortex Hormones↗
PubMed1993

Childhood adversity and adult defence style in eating disorder patients--a controlled study.

The aims of the study were (1) to compare the defence style of patients with anorexia nervosa with that of patients with bulimia nervosa and of female controls; (2) to establish whether a link exists between childhood adversity and adult defence style in eating disorder patients. Twenty-six patients with restricting anorexia nervosa (RAN), 61 patients with bulimia nervosa (BN), 37 patients with bulimic anorexia nervosa or bulimia nervosa with a history of anorexia nervosa (BAN/BN-HistAN) and 88 female controls were given the short Defense Style questionnaire (Andrews, Pollock & Stewart, 1989). Eating disorder patients were asked about their childhood care using a semi-structured interview (Harris, Brown & Bifulco, 1986). Bulimia nervosa patients had a significantly less mature defence style than the other groups and like the BAN/BN-HistAN group more immature defences than the control group. In the RAN group no childhood predictors of adult defence style were found, whereas in bulimia nervosa, excessive parental control during childhood was a negative predictor of mature defences and physical abuse a positive predictor of immature defence style. These results provide some evidence that childhood adversity may constitute a vulnerability factor for the later development of bulimia nervosa, mediated by personality development.

Adolescent↗
PubMed1993

Effect of inotropic stimulation on the negative force-frequency relationship in the failing human heart.

BACKGROUND: In severe human heart failure, an increase in frequency of stimulation is accompanied by a reduced force of contraction in vivo and in vitro. The present study was aimed to investigate whether inotropic stimulation influences the inverse force-frequency relationship in failing human myocardium. METHODS AND RESULTS: The effects of the cAMP-independent positive inotropic agents ouabain (0.01 mumol/L) and BDF 9148 (0.1 mumol/L) as well as the beta-adrenoceptor agonist isoprenaline (0.01 mumol/L and 0.1 mumol/L) on the force-frequency relationship in electrically driven papillary muscle strips from nonfailing (brain death, n = 5) and terminally failing (NYHA class IV, heart transplants, dilated cardiomyopathy, n = 22) human myocardium were studied. For comparison, we examined the effect of elevation of the extracellular Ca2+ concentration (3.2 mmol/L and 6.2 mmol/L). In nonfailing myocardium, force of contraction, peak rate of tension rise, and peak rate of tension decay increased, whereas time to peak tension and time to half relaxation decreased following an increase of stimulation frequency. In NYHA class IV, force of contraction gradually declined followed by changes of other parameters of isometric contraction. Moderate stimulation of contractility by isoprenaline (0.01 mumol/L) partly reversed the negative force-frequency relationship in NYHA class IV and preserved the positive force-frequency relationship in nonfailing myocardium. The addition of ouabain and BDF 9148 together restored completely the force-frequency relationship in NYHA class IV. In contrast, high concentrations of isoprenaline (0.1 mumol/L) and an elevation of the extracellular Ca2+ concentration enhanced the decline in force of contraction in the presence of higher stimulation frequencies. CONCLUSIONS: It is concluded that functionally important changes occur in the intracellular Ca2+ handling, leading to the negative force-frequency relationship in terminally failing human myocardium. Interestingly, the negative force-frequency relationship can be restored by agents producing positive inotropic effects by elevation of the intracellular Na+ concentration. These findings suggest that hitherto unknown changes in the intracellular ionic homeostasis occur in the failing human heart. Even though increasing [Ca2+]i in failing heart cells may be detrimental, increasing [Na+bdi may be beneficial through a mechanism independent of an increase in [Ca2+]i.

Adult↗
PubMed1993

Cardiac adenylyl cyclase, beta-adrenergic receptors, and G proteins in salt-sensitive hypertension.

The present study investigated whether high salt intake (8%) in Dahl salt-sensitive and salt-resistant rats with and without hypertension produces a heterologous desensitization of cardiac adenylyl cyclase as observed in various types of hypertension and human heart failure. In membranes from Dahl salt-sensitive rats on a high-salt diet (8%) basal, isoproterenol-, 5'-guanylylimidodiphosphate-, and forskolin-stimulated adenylyl cyclase was reduced compared with the low-salt (0.4%) group and Dahl salt-resistant rats on either 0.4% or 8% sodium chloride. The activity of the catalyst was depressed, and the expression of the immunodetectable inhibitory G proteins Gi alpha was increased in Dahl salt-sensitive rats on 8% sodium chloride, whereas the density of beta-adrenergic receptors and the activity of the stimulatory G protein Gs alpha reconstituted into Gs alpha-deficient S49 cyc- mouse lymphoma cell membranes were unchanged in any condition studied. We conclude that high salt intake in salt-sensitive hypertensive Dahl rats produces hypertension, cardiac hypertrophy, and heterologous desensitization of cardiac adenylyl cyclase. The latter alteration is due to an increase of Gi alpha proteins and a depressed catalyst activity of adenylyl cyclase. The results demonstrate that heterologous adenylyl cyclase desensitization can precede the development of contractile dysfunction in later stages and can occur independently of changes in beta-adrenergic receptors.

Adenosine Diphosphate Ribose↗
PubMed1993

[Differential liver siderosis diagnosis using quantitative iron determination in the biopsy specimen].

Quantitative iron investigations were carried out in the leavings of liver biopsy specimens from 92 patients with liver siderosis, detected by histochemical methods. A discrimination between primary and secondary liver siderosis were tried by the liver iron index. Idiopathic hemochromatosis was not found in liver iron indices below 2, both hemochromatosis and secondary liver siderosis were found with an index above 2. Only idiopathic hemochromatosis was found with an index above 5 with the exception of one transfusional siderosis in refractory anemia.

Biopsy↗