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Biomedical subjects

I Bauer

Publications and source records attributed to I Bauer.

At least 37 records · Page 2Linked to original sources
PubMed1995

Chronic ethanol consumption increases hepatic sinusoidal contractile response to endothelin-1 in the rat.

Recent evidence suggests that hepatic stellate cells function as liver-specific pericytes that are highly contractile in response to endothelin-1 (ET-1). Liver injury has been shown to lead to "activation" of stellate cells producing a phenotypic change to a more myofibroblastic cell type including loss of vitamin A and increased contractility. The present study was undertaken to test the effects of short-term chronic ethanol consumption (36% of total calories for 5 weeks according to the Lieber-DeCarli protocol) on hepatic vitamin A storage, expression of smooth muscle alpha-actin, and sinusoidal contractility in Sprague-Dawley rats. Using in vivo epifluorescence video microscopy, we quantified the number of sites of vitamin A fluorescence (purportedly stellate cells) and assessed sinusoidal microhemodynamics at baseline and during a 20-minute infusion period of ET-1 (1 pmol * 100 g body weight [bw]*1*min-1). Retinol and retinyl palmitate were measured after the experiment by means of high-pressure liquid chromatography (HPLC). A highly significant decrease in liver retinyl palmitate level (control: 622.5 +/- 50.9; ethanol: 273.0 +/- 38.0 microgram/g liver; P< .001) was found that correlated with a decrease in sites of vitamin A fluorescence (control: 531.4 +/- 76.1; ethanol: 141.1 +/- 30.2* mm-2; r = .82, P <.001). Concomitantly scattered expression of smooth muscle alpha-actin in sinusoids was observed. Although sinusoidal hemodynamics were not affected at baseline, a significant increase in sinusoidal contractility on endothelin-1 infusion (e.g., sinusoidal resistance [% of baseline value]: control: 10 minutes: 288.7 +/- 71.7, 20 minutes: 200.5 +/- 46.9; ethanol: 10 minutes: 1,916.0 +/- 701.7, 20 minutes: 656.8 +/- 103.3; P < .05 and .01, respectively) was observed. These data indicate that chronic ethanol consumption in this moderate model initiates stellate cell activation. Increased sinusoidal responsiveness to the vasoconstrictor ET-1 in vivo may contribute to the increased susceptibility of ethanol-fed rats to secondary stresses that increase ET-1 expression, such as endotoxemia.

Actins↗
PubMed1994

Nursing at dawn. Nursing tasks in the first hour of the morning shift in a German hospital.

Nurses' working hours are known to be one reason for high wastage rates. The early start of work seems to be particularly difficult. The aim of the present study was to examine which nursing tasks were performed during the time from 6:00 to 7:00 a.m. The study was conducted in a general hospital in Germany where such an early start of work is still common practice. An activity analysis was carried out using non-participant observation. One surgical and one medical ward were used for comparison. The work on the wards was differently organized. The observed tasks were classified into direct care, indirect care, administrative, and other tasks. The distribution of these task categories over one hour and the percentage of time spent on these categories were compared. Both wards showed different working patterns and a different form of initiation of direct care (entering patients' rooms). Some possible reasons for these findings are offered and suggestions for further research are made.

Germany↗
PubMed1994

ET-1 induced alterations of hepatic microcirculation: sinusoidal and extrasinusoidal sites of action.

Using epifluorescence microscopy, we investigated the dynamic changes in hepatic sinusoidal hemodynamics in vivo during continuous infusion of endothelin-1 (ET-1) in pentobarbital-anesthetized rats. ET-1 was infused for 20 min at rates of 2 or 10 pmol/min either systemically or into the portal vein, followed by a 90-min recovery period. In contrast to systemic application of ET-1 that did not cause a consistent hepatic microvascular effect, we observed two different patterns of microcirculatory alterations during portal application. Infusion of 2 pmol/min elicited a rapid, reversible decrease in sinusoidal diameter that was paralleled by a slight increase in red cell velocity, resulting in conservation of volumetric flow and sinusoid density. Infusion of 10 pmol/min resulted in a biphasic narrowing followed by transient increase in sinusoidal diameter and a profound and lasting decrease in red cell velocity, leading to an almost complete cessation of hepatic microvascular blood flow. These results indicate that ET-1 is a potent constrictor in the liver microcirculation in vivo and acts at both extrasinusoidal and sinusoidal sites, although the sinusoidal sites appear to be more sensitive to lower concentrations.

Animals↗
PubMed1994

Endothelin-1 as a regulator of hepatic microcirculation: sublobular distribution of effects and impact on hepatocellular secretory function.

Endothelin-1 is a potent vasoconstrictor in the portal circulation causing sinusoidal constriction as well as presinusoidal resistance changes. Using in vivo videomicroscopy we studied the sublobular differences in dose response characteristics of sinusoid constriction at 10-13 min into continuous infusion of 5, 1.0, 3.0, and 5.0 pmol of endothelin-1 (ET-1)/100 g body weight/min in pentobarbital anesthetized rats. In addition, bile flow was monitored to estimate parenchymal secretory function. ET-1 evoked a profound constrictor effect in both sublobular regions studied. However, the maximal decrease of sinusoidal width in periportal inflow region (zone 1; 1 pmol/100 g/min: 4.8 +/- .1 microns) was reached at slightly lower concentrations of the peptide than in pericentral outflow region (zone 3; 3 pmol/100 g/min: 6.2 +/- .3 microns) compared to respective baseline values (zone 1: 7.1 +/- .1 microns; zone 3: 10.2 +/- .1 microns), suggesting upstream binding and clearance of the peptide. The constrictor response in zone 1 was biphasic and at higher concentrations of the peptide (5 pmol/100 g/min: 5.5 +/- .2 microns) sinusoidal widths increased again compared to the maximal response with the 1 pmol. Secretory function as reflected by the bile flow was maintained or even slightly increased with the lower doses (.5 and 1 pmol) of ET-1 and during the first 10 min into infusion of the higher doses (3 and 5 pmol). Subsequently, an approximately 20-25% decrease in bile flow accompanied the infusion of higher doses of ET-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Classification, a suitable method for nursing research--practical advice for data collection and data analysis].

Arranging subjective data in rank order is a simple method for making comparisons of judgements and evaluating them. Since it is difficult to find practical instructions for this which can be easily understood, this paper uses data obtained in a study of patients' opinions about their privacy. Results are analysed, presented and explained. The method is appropriate for a wide range of research in which individuals are asked for opinions.

Data Collection↗
PubMed1993

A clinical application of the multiple sorting technique.

The interview technique is a common method of collecting data in human research. This paper provides an example of the use of the multiple sorting technique for structuring and analysing qualitative interviews. The technique is described around a recently completed study which explored practising nurses' perception of their work in a German hospital. A multiple sorting technique was employed to structure interviews with 11 nurses. Nursing tasks were sorted into categories and labelled by respondents. The frequencies with which each task was paired with all of the other tasks were calculated and this allowed us to produce a similarity matrix which was entered as input into a multidimensional scaling procedure (Smallest Space Analysis SSA-1). The SSA-1 procedure was used to analyse and interpret the data. The results of the analysis indicated that the nurses conceptualized their work into four separate domains including basic care skills, indirect care, technical skills and administration. The example of the multiple sorting technique described here shows how it is possible to develop an insight into the nurses' world in a structured yet flexible way.

Data Collection↗
PubMed1993

Nurses' perception of the first hour of the morning shift (6.00-7.00 a.m.) in a German hospital.

Morning shifts in Germany usually start at 6.00 a.m. Apart from the well-known effects of shiftwork on health and family/social life, the early rising time poses additional problems. Part of a study on the first hour of the morning shift is described in this paper. Thirteen nurses on a female surgical and on a male medical ward were interviewed using a semi-structured interview guide. The findings were obtained through phenomenological analysis. Seven themes emerged from the results: (a) the impact of rising early on the individual, (b) the detrimental effect of alternating shifts on well-being, (c) disturbances to personal life, (d) the rationale for early start, (e) consequences for patients, (f) suggestions for change, and (g) increased risk of leaving the job. The findings suggest that the early start puts nurses under considerable stress. Tradition rules the time-oriented and ritualized way of organizing work. Further extensive research is recommended.

Germany↗
PubMed1992

Prevalence of cystic fibrosis mutations in the East German population.

A representative multicenter cystic fibrosis (CF) mutation analysis on about half of all known cystic fibrosis patients of the 5 East German Länder is reported. Analyses for 17 mutations, among them Delta F508, R553X, G542X, S549R,N,I, G551D, S1255X, R347P,H, and Y122X, were performed. As expected, the delta F508 mutation in exon 10 of the CFTR gene is the major gene alteration causing CF in our patients. However, in comparison to studies from Western Germany, a significantly lower percentage of just over 60% is found in our patients, resembling data obtained from slavonic populations. The severe phenotype of cystic fibrosis is most frequently associated with homozygosity for the delta F508 mutation. No particular allele association could be found with the intermediate and mild phenotypes of this disease. The next most frequent of the investigated mutations is R553X (13.3% of non-delta F chromosomes) followed by R347P (9.2%) and G542X (4.4%).

Cystic Fibrosis↗
PubMed1992

Hypomagnesaemia in type 2 (non-insulin-dependent) diabetes mellitus is not corrected by improvement of long-term metabolic control.

Low levels of magnesium have frequently been reported in diabetes mellitus especially in poorly controlled Type 1 (insulin-dependent) diabetic patients. Furthermore hypomagnesaemia might contribute to insulin resistance in Type 2 (non-insulin-dependent) diabetes. As the influence of improved metabolic control on plasma magnesium levels is unknown in Type 2 diabetic patients we studied magnesium plasma levels in 50 patients 1) before, 2) one and 3) three months after the initiation of insulin therapy or intensified treatment with oral hypoglycaemic agents. Magnesium plasma levels were measured by a colorimetric method and were significantly reduced in diabetic patients compared to healthy control subjects (0.79 +/- 0.01 mmol/l vs 0.88 +/- 0.01 mmol/l; p less than 0.0001). Metabolic control was significantly improved as documented by reduced HbA1C levels in both insulin-treated patients or the patients on oral hypoglycaemic agents (p less than 0.003). However, plasma magnesium levels remained unchanged during the follow-up in the insulin-treated group (1: 0.79 +/- 0.02 mmol/l; 2: 0.81 +/- 0.02 mmol/l; 3: 0.79 +/- 0.01 mmol/l) as well as in the patients on oral hypoglycaemic agents (1: 0.79 +/- 0.03 mmol/l; 2: 0.78 +/- 0.02 mmol/l; 3: 0.84 +/- 0.04 mmol/l). This study shows that even marked improvement of glycaemic control does not correct hypomagnesaemia in Type 2 diabetes. We conclude that hypomagnesaemia might be related to the insulin-resistant state and that possible beneficial effect of chronic magnesium administration should be evaluated in these patients.

Blood Glucose↗
PubMed1992

[Detection of human papillomaviruses (HPV) in laryngeal papilloma. An in situ hybridization study].

Together 35 papillomas of the larynx (8 juveniles, 27 adults) were studied for the presence of HPV-DNA by means of nucleic acid hybridization. The hybridization procedure was carried out "in situ" with biotinylated probes of HPV 6/11 and 16/18 under stringent conditions. The results are shown in Table 1. In all juvenile papillomas we detected HPV 6/11, but we did not find positive signals after hybridization with HPV 16/18, 25 (92.6%) of the examinated adult papillomas were HPV 6/11 positive. The detection procedure of HPV 16/18 was positive twice (11.8%). The results of our studies support the hypothesis of HPV 6/11 in development of larynxpapillomas.

Adult↗
PubMed1992

[Type 6/11 and 16/18 squamous epithelial cancers of the upper respiratory tract and digestive system. An in situ hybridization study].

61 squamous cell cancers (27 laryngeal, 12 hypopharyngeal, 14 tonsillary, 8 tongue) with different keratinization and grading and seven lymph node metastases of HPV 16/18 positive carcinomas were analysed for the presence of HPV-DNA by in situ hybridisation. 65.5% of them were found to be positive. Twelve laryngeal carcinomas (44%), five tonsillary tumours (35.7%), eight tumours of the hypopharynx (66.6%) and three tongue carcinomas (37.5%) were shown to contain HPV 16/18 DNA. The detection rates of HPV 6/11 were lower. 44 of the analysed tumours (72.1%) had a grading G2. 29 of these tumours (65.9%) were HPV positive. Only eight of the patients were no heavy smokers or alcoholic drinkers. One of the lymph node metastases was positive for HPV 16/18. The results indicate that HPV may be involved in the pathogenesis of squamous cell carcinomas of head and neck tumours.

Biopsy↗
PubMed1991

[Use of the Dot-Blot technique in the detection of human papillomavirus(HPV) deoxyribonucleic acid (DNA) in malignant tumors of the oropharynx].

A total of 23 malignant oropharyngeal tumours (palate, tongue, tonsils, pharynx) and two lymph node metastases were analysed for presence of papilloma virus DNA. Thirteen (54.5%) of 22 squamous cell cancers of different koilocytosis and grading were found to contain HPV 16/18 DNA. Only 16.6% (4 cases) were positive for HPV 6/11 DNA. There was no detectable HPV-DNA in the lymph node metastases (Table 1). The control biopsies (19) were negative after hybridisation.

Aged↗