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Biomedical subjects

B Hartmann

Publications and source records attributed to B Hartmann.

At least 127 records · Page 7Linked to original sources
PubMed1991

[Increase in skin blood circulation and transcutaneous oxygen partial pressure of the top of the foot in lower leg immersion in water containing carbon dioxide in patients with arterial occlusive disease. Results of a controlled study compared with fresh water].

Semi-quantitative Doppler laser flowmetry and measurement of transcutaneous oxygen partial pressure (TCPO2 in mmHg) are reliable, non-invasive methods of continuous measurement suitable for underwater use. We measured the effect of aqueous CO2 (succinate + sodium bicarbonate = Kao Bub; 1400 mg CO2 per kg water) compared with fresh water (both at 34 degrees C, depth of leg immersion 35 cm, immersion time 20 min) on circulation and TCPO2 in the feet of 15 patients with bilateral stage-II occlusion of the Aa. fem. superf. intraindividually in a randomised, crossover trial. Measurements were made at the same time of day on two consecutive days. No change in either cutaneous microcirculation or TCPO2 was observed during immersion in fresh water. During immersion in a CO2 bath both culaneous blood flow (as expressed by Doppler laser flux) and the amplitude of the Doppler laser vasomotion flux increased more than threefold (p less than 0.001, Wilcoxon), while sitting TCPO2 increased by over 10% (from 63 to 71 mmHg; p less than 0.001). The observed changes in oxygen dissociation and cutaneous microcirculation may help to provide an explanation for the well-known therapeutic effect of CO2 baths in all stages of occlusive arterial disease.

Adult↗
PubMed1991

[Stress on adolescents due to forced positions in various postural loads].

To assess the strain imposed by defined static loads, eleven young males were studied in four different postures at three different loads held. In addition to the usual cardiovascular parameters of heart rate and arterial blood pressure, the long-term variability of the cardiac cycle (sinus arrhythmia) and the subjective exertion assessment according to Borg were used as strain criteria. Despite a high interindividual variability, HR arrhythmia data reflect in very good terms the strain imposed by predominantly central activation at static loads and forced postures. Such a strain assessment does not replace other modes of assessment such as biomechanical model considerations. Still, it may add to an assessment made on the basis of heart rate and blood pressure.

Adolescent↗
PubMed1990

Expression of 38-kD cell-surface glycoprotein in transformed human keratinocyte cell lines, basal cell carcinomas, and epithelial germs.

In this study, we attempted to identify and characterize transformation-induced cell-surface glycoproteins of human keratinocytes. Therefore, we first searched for glycoproteins which are significantly elevated in human keratinocytes after transformation and immortalization by SV40 virus and which are also found at high levels in keratinocytic cell lines derived from squamous cell carcinomas of the skin. Out of at least 80 different cell-surface antigenic systems of human tumor cells, only three glycoproteins showed elevated expression in transformed keratinocytes. Among these, a 38-kD glycoprotein (gp 38) was highly increased in all transformed keratinocyte cell lines tested, but was not elevated in transformed fibroblasts. The expression of gp 38 was further characterized in normal epidermis and in its benign and malignant hyperproliferative disorders: gp 38 was generally not expressed in normal epidermis and in benign hyperproliferative disorders. In contrast, strong and homogeneous reactivity was found in solid and fibrosing basal cell carcinomas whereas no or low reactivity was detected in squamous cell carcinomas and in those parts of BCC revealing keratotic differentiation. Interestingly, high expression of gp 38 was also found in primary epithelial germs of fetal skin, secondary germ cells of the telogenic hair follicle and secretory tubules of sweat glands. The immunohistologic data suggest that gp 38 is preferentially expressed by epidermal cells which lack squamous and pilosebaceous differentiation.

Basal Cell Carcinoma↗
PubMed1990

[Results of audiometry screening in adolescent workers].

Results of screening audiometry of male youths aged 16 to 25 (n = 3969) in occupations from metallurgy, machine-building industry and traffic are demonstrated. Part of persons they have hearing loss between 5 to 10 percent increases from 2.8% of pupils before starting vocational training to 4.5% or 7.1% of apprentices and 9.7% of skilled workers. The incidence of persons with respective without middle ear inflammation in anamnesis only differ in stages about 20 percent hearing loss. It shows sensitivity of screening audiometry nevertheless there are possibilities of mistakes. Adolescents already may show measurable hearing loss in connection with professional and nonprofessional expositions as well as individual dispositions.

Adolescent↗
PubMed1989

Theoretical prediction of base sequence effects in DNA. Experimental reactivity of Z-DNA and B-Z transition enthalpies.

Molecular modeling is used to study the sequence dependence of conformation and stability within helically regular duplex Z-DNA. The variations of conformation that are found are sufficiently important to be classified as a new type of polymorphism within the Z family. It is also demonstrated that certain sequences can adopt more than one of these polymorphic forms. Comparison with experimental studies of chemical reactivity within a natural DNA fragment, forced into a left-handed conformation, suggests that the results of our modeling may be used to explain the chemical reactivity observed. Comparison of the Z results with similar studies of the B form allow enthalpies of transition to be calculated as a function of base sequence.

Algorithms↗
PubMed1989

The conformation and stability of ribonucleic acids: modeling base sequence effects in double stranded helices.

Base sequence effects within double stranded RNA oligomers of A and Z conformations have been studied by molecular modeling using a methodological approach specifically adapted to nucleic acids. Calculations on symmetric oligomers having homonucleotide or dinucleotide repeating base sequences show that sequence changes can produce modifications in overall conformation, influence the degree of internal hydrogen bonding and strongly affect stability.

Base Sequence↗
PubMed1989

[The effect of carbon dioxide baths on blood pressure of borderline hypertensive patients].

In 423 patients with borderline hypertension (at rest and/or during exercise) the potential blood pressure reducing effect of CO2-baths was studied. Using standardized blood pressure measurements at rest and during exercise, it was investigated to what extent a fourweek course of CO2-baths could induce a reduction of blood pressure in these patients. They were randomly assigned to a course of baths with either high or low CO2-concentration. A significant fall in blood pressure, both at rest and during exercise was observed in both groups during the course of treatment. Multiple regression analysis identified the loss in body weight during treatment as the main influence factor on reduction in blood pressure. By contrast, no (additional) specific therapeutic effect of CO2-baths on blood pressure reduction could be observed.

Adult↗