Biomedical subjects

Stefan Schmidt

Publications and source records attributed to Stefan Schmidt.

25 records · Page 2Linked to original sources

PubMed2002

[Training and educational measures in severe chronic heart failure. Experiences and application to general practice].

OBJECTIVES: Prognosis and course of severe left ventricular dysfunction have been shown to be influenced positively by exercise training. Yet, physicians have been reluctant to include exercise into therapeutic concepts due to widespread uncertainty about the acceptable intensity of cardiac stress. Standardized exercise programs with proven safety may promote acceptance of this approach. PATIENTS AND METHODS: 25 patients with severe heart failure were enrolled in a PC-controlled interval exercise training on cycle ergometer, lasting 21 minutes five times a week for a 4-week inpatient period. After discharge patients performed incremental daily walking for 3 months. Associated educational measures concerned life-style changing and self-controls. RESULTS: None of the patients had to interrupt the training because of side effects. 3 weeks and 3 months after starting exercise training there was an increase of peak VO2 from 13.4 +/- 2.8 to 14.5 +/- 3.8 (p < 0.05) and 15.3 +/- 3.2 ml/kg/min (p < 0.01), respectively, and an increase of ventilatory anaerobic threshold (VAT) from 9.3 +/- 1.9 to 10.0 +/- 2.3 (p < 0.05) and 11.3 +/- 2.2 ml/kg/min (p < 0.001), respectively. The improved aerobic capacity corresponded to a 9.3% increase in the results of the 6-minute walk test in the 4th week (n.s.). During out-patient period, the walking could be increased from 37 to 58 minutes daily. The physical quality of life was significantly improved after 3 months. There was no hospital admission due to heart failure. CONCLUSION: Exercise training in the therapy of severe heart failure is safe and increases the aerobic capacity. Associated educational measures may be able to minimize the danger of wrong exercise techniques and to reduce the rate of hospital readmissions.

Adult↗

PubMed2002

The effects of a caffeine placebo and suggestion on blood pressure, heart rate, well-being and cognitive performance.

We studied the effect of suggestion and different instructions in a balanced placebo design. One hundred and fifty-nine subjects were randomized into a 2*4 factorial design. All subjects except a control group received a caffeine placebo. Subjects were randomized to a condition which was identical to an earlier study, or received an information about scientifically proven effects of caffeine (factor 1). The second factor varied instructions: subjects were either made to expect coffee, no coffee or were in a double blind condition and were told either coffee or placebo would be applied. Dependent measures were blood pressure, heart rate, well-being and a cognitive task. There was one main effect of the instruction factor (P=0.03) on diastolic blood pressure, with the group 'told caffeine' reporting significantly smaller decrease in diastolic blood pressure than controls and subjects in the double blind condition. There were no other main effects on both the instruction or suggestion factor, and no interactions. Contrary to the literature, instruction effects were very small. This was apparently due to the fact that placebo-caffeine in the dose used in this study--one cup of strong 'coffee'--did not produce expectancy effects strong enough to affect the parameters measured. It is concluded that the placebo-caffeine research paradigm is not suitable for researching instruction effects in Germany, and that reported effects should be reproduced with tighter controls.

Adolescent↗

PubMed2002

Biotransformation of naphthalene and diaryl ethers by green microalgae.

The role of green microalgae in the biotransformation of naphthalene (a polycyclic aromatic hydrocarbon) and diaryl ethers was investigated using axenic cultures of Chlorella vulgaris and two environmental isolates, Scenedesmus SI1 and Ankistrodesmus SI2. Biotransformation experiments with dense cell cultures showed that these three green algae transformed toxic xenobiotics to more polar metabolites. Chlorella vulgaris metabolized naphthalene to 1-naphthol (0.36-0.65%). Ankistrodesmus SI2 biotransformed dibenzofuran to six metabolites (total over 7%), three of which (possibly four) were identified as monohydroxylated dibenzofurans, the remaining two may be dihydroxylated derivatives. Scenedesmus SI1 biotransformed dibenzo-p-dioxin to three metabolites, one of which was tentatively identified as 2-hydroxydibenzo-p-dioxin (approximately 3.8%), the remainder may be dihydroxylated derivatives. This is the first time that the biotransformation of diaryl ethers by green microalgae has been investigated.

Biodegradation, Environmental↗

PubMed2002

Biotransformation of 2,7-dichloro- and 1,2,3,4-tetrachlorodibenzo-p-dioxin by Sphingomonas wittichii RW1.

Aerobic biotransformation of the diaryl ethers 2,7-dichlorodibenzo-p-dioxin and 1,2,3,4-tetrachlorodibenzo-p-dioxin by the dibenzo-p-dioxin-utilizing strain Sphingomonas wittichii RW1, producing corresponding metabolites, was demonstrated for the first time. Our strain transformed 2,7-dichlorodibenzo-p-dioxin, yielding 4-chlorocatechol, and 1,2,3,4-tetrachlorodibenzo-p-dioxin, producing 3,4,5,6-tetrachlorocatechol and 2-methoxy-3,4,5,6-tetrachlorophenol; all of these compounds were unequivocally identified by mass spectrometry both before and after N,O-bis(trimethylsilyl)-trifluoroacetamide derivatization by comparison with authentic standards. Additional experiments showed that strain RW1 formed a second metabolite, 2-methoxy-3,4,5,6-tetrachlorophenol, from the original degradation product, 3,4,5,6-tetrachlorocatechol, by methylation of one of the two hydroxy substituents.

Biotransformation↗

PubMed2002

Associations between body mass, leptin, IGF-I and circulating adrenal androgens in children with obesity and premature adrenarche.

OBJECTIVE: To explain why adrenal androgens rise with increasing adiposity during childhood, the role of body mass index (BMI), leptin and IGF-I was studied. We also tested whether these parameters contribute to inducing premature adrenarche (PA). DESIGN: In a cross-sectional study, 26 prepubertal obese children were compared with a group of 26 prepubertal children of normal weight, and 30 children under observation for PA were compared with 30 healthy children, matched for gender, bone age and BMI. METHODS: Relative contributions of BMI standard deviation scores (SDS) and height SDS, as well as unbound leptin and IGF-I, to the levels of androgens, dehydroepiandrosterone sulfate (DHEAS) and Delta4-androstenedione (AD) were investigated by means of stepwise regression models. Logarithms of all hormones were standardised for age using residuals of a simple regression analysis, labelled by the suffix '(res)'. RESULTS: In the obese children, height SDS, IGF-I(res,) DHEAS(res) (all P<0.05), leptin(res) (P<0.01), and AD(res) (P=0.07) were higher than in the controls, and covariates were correlated with each other (leptin(res) versus BMI SDS r=0.71, IGF-I(res) versus height SDS r=0.61). In the stepwise regression analysis of control and obese children, BMI SDS explained 26% and leptin(res) explained 12% of the variability of DHEAS(res), but this percentage remained at 26% when both variables were simultaneously introduced into the model. In contrast, IGF-I(res) and BMI SDS alone each accounted for 15% of the variability of AD, and their joint influence accumulated to explain 28% of the variability of AD(res). In PA, neither BMI SDS nor leptin(res) were correlated with the increased androgens. CONCLUSION: Before the onset of gonadal activity in obese and control children, DHEAS levels, to some extent, are explained by BMI and leptin, while IGF-I in addition to BMI in part accounts for AD levels. Enhanced adrenal androgen secretion in children with PA, however, may be explained by parameters other than leptin or BMI.

Adolescent↗

PubMedDate not supplied

Characterization of the human SLC2A11 (GLUT11) gene: alternative promoter usage, function, expression, and subcellular distribution of three isoforms, and lack of mouse orthologue.

GLUT11 (SLC2A11) is a class II sugar transport facilitator which exhibits highest similarity with the fructose transporter GLUT5 (about 42%). Here we demonstrate that separate exons 1 (exon 1A, exon 1B, and exon 1C) of the SLC2A11 gene generate mRNAs of three GLUT11 variants (GLUT11-A, GLUT11-B, and GLUT11-C) that differ in the amino acid sequence of their N-termini. All three 5'-flanking regions of exon 1A, exon 1B and exon 1C exhibited promoter activity when expressed as luciferase fusion constructs in COS-7 cells. 5'-RACE-PCR, quantitative real-time PCR, and Northern blot analysis performed with specific probes for exon 1A, 1B and 1C demonstrated that GLUT11-A is expressed in heart, skeletal muscle, and kidney, GLUT11-B in kidney, adipose tissue, and placenta, and GLUT11-C in adipose tissue, heart, skeletal muscle, and pancreas. Surprisingly, mice and rats lack the SLC2A11 gene. When expressed in Xenopus oocytes, all three GLUT11 isoforms transport glucose and fructose but not galactose. There was no apparent difference in the subcellular distribution of the three isoforms expressed in COS-7 cells. Our data indicate that different promoters and splicing of the human SLC2A11 gene generate three GLUT11 isoforms which are expressed in a tissue specific manner but do not appear to differ in their functional characteristics.

Alternative Splicing↗

PubMedDate not supplied

Distant healing intention: definitions and evolving guidelines for laboratory studies.

This paper provides definitions and a discussion of evolving guidelines for conducting research on the effects of distant healing intention (DHI) on living systems in the laboratory. We consider the relevance of DHI laboratory research to applied healing, special theoretical challenges, and other considerations that distinguish DHI research from other domains of laboratory science. Two sample protocols for investigating DHI are provided, one involving the human autonomic nervous system as the "target" of distant intention, and the other involving cell cultures. In essence, DHI differs from other alternative healing modalities because it postulates that mental intention alone can affect living systems at a distance, unbounded by the usual constraints of both space and time. This postulate challenges scientific assumptions that often go unexamined, including the nature of causality, the distinction between subjective and objective states, and the efficacy of double-blind protocols in controlling for experimenters' intentions. Previous laboratory research in this domain suggests that DHI effects warrant serious study, but most scientists and funding agencies are unaware of the evidence or the relevant literature. By following these evolving guidelines, researchers' designs and their ultimate publications will conform more closely to the quality standards expected by scientific journals, and such publications will in turn attract the attention of a broader range of scientists. This seems especially important for alternative healing research in general and for distant healing in particular; both realms enjoy broad public support but have largely eluded serious attention by mainstream science.

Brain↗