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Biomedical subjects

U Gerhardt

Publications and source records attributed to U Gerhardt.

At least 55 records · Page 3Linked to original sources
PubMed1992

[Progress in the use of tissue expanders for defect closure of the body surface--experimental principles].

The principle of soft tissue expansion has been applied in widespread techniques in the field of plastic and reconstructive surgery since Radovan (1976) presented a method in which silicone expanders were subcutaneously implanted. Many experimental and clinical reports have been published since then, dealing particularly with the histomorphology, vascularization, and pathophysiology of expanded skin as well as with surgical techniques. Our own study intends to identify the effects of tissue expanders on the biomechanical, biochemical, and morphological qualities of expanded skin, and to determine the influence of pharmacological therapy during expansion.

Animals↗
PubMed1992

[Counseling work with foreign families].

In spite of informations about a rapid change of behavioral patterns, immigrant children, youth and families have problems to keep their identity and being understood in the guest countries. Assistance of any kind and especially counseling in intrapsychic and social conflicts has to follow special topics. There are not only language barriers, the adviser has to take care of the ethnological background and the social-cultural conditions of the home country, he has to know about loyalty mechanisms to the family of origin, to manage closeness and distance in interactional relationship. Often he has also to help children and adult persons to experience self-confidence and self-conciousness in solving psychological problems instead of helplessness and waiting for magic and mystic help.

Acculturation↗
PubMed1990

Elimination of variable vasomotor tone in studies with repeated quantitative coronary angiography.

In quantitative coronary angiographic studies, unintentional changes of coronary vasomotor tone may have a significant influence on the coronary artery diameters, thereby increasing the variability in the measurements. To obtain objective data on these measurement variabilities, two protocols were designed to assess the influences of ionic and nonionic radiographic contrast media on the mean diameters of angiographically normal coronary arteries. The vessel sizes were determined with the CAAS using automated edge detection techniques. In 21 patients (study no. I), coronary angiograms were taken in identical angiographic projections before (control), and immediately following several (at average 7) subsequent diagnostic dye injections administered over a period of about 7 min. The ionic contrast agent diatrizoate 76% induced a coronary dilation of 19 +/- 7% (mean +/- s.d., p less than 0.001; n = 10); the nonionic agent iopromide 370 increased the coronary artery diameters by only 6 +/- 4% (p less than 0.01; n = 11). In another 11 patients (study no. II) coronary angiograms were obtained using the nonionic contrast medium iopamidol 300 at 5, 8, 10 and 11 min after the control acquisition; this protocol was repeated in the same patients with diatrizoate 76%. With iopamidol, coronary diameter changes were not significant at any time; with diatrizoate, however, coronary dilation was measured at 10 min (2 +/- 2%; p less than 0.01) and at 11 min (10 +/- 3%; p less than 0.001). In a third study it was tested, whether standardization of coronary vasomotor tone (e.g. in coronary angiographic follow-up studies) is possible by the induction of a reproducible maximum coronary dilation with nitrocompounds. In 12 patients, the mean diameters of angiographically normal coronary segments were analyzed before and at various times after i.v. administration (over 4 min) of 0.025 mg SIN-1/kg bodyweight. Coronary dilation was maximal at 10 or 15 min after the onset of the SIN-1-infusion (29 +/- 5%; p less than 0.001). 0.8 mg nitroglycerin given s.l. at 15 min did not further dilate the coronary arteries (28 +/- 7%). One hour after SIN-1, coronary dilation still amounted to an average of 24 +/- 8% (p less than 0.001) and became 'maximal' again, when 0.8 mg nitroglycerin was again administered sublingually (28 +/- 8%; p less than 0.001). In conclusion, short-term variability of coronary vasomotor tone induced by ionic radiographic contrast media can be eliminated by the use of nonionic contrast agents and observation of injection intervals of at least 2 min. In quantitative coronary angiographic follow-up studies, as well as during acute interventions (e.g., PTCA), identical baseline vasomotor tone can be achieved by induction of the maximal coronary dilation using nitrocompounds.

Adult↗
PubMed1990

Patient careers in end-stage renal failure.

This paper argues that coping with end-stage renal failure can be analysed in terms of status structures. Biographical narratives from 68 cases of British male married patients of working age and data from four follow-ups covering a time period of up to 12 years are interpreted as evidence of structured career patterns. The method of data interpretation is adapted from Max Weber's ideal type venturing a systematic analysis of life-history (qualitative) material.

Adaptation, Psychological↗
PubMed1989

The sociological image of medicine and the patient.

Jack Elinson raises somewhat rhetorical questions about the value of medical care and medical sociology. Behind them is a serious concern with the type and scope of medicalisation in modern society as well as its sociological criticism. This raises the issue of whether the various theoretical images of medicine and the patient which sociology provides are able to account for the effect of the social environment upon morbidity and mortality as shown, for instance, by the Alameda County Study. Three theoretically distinct approaches are discussed in detail, structural functionalism, symbolic interactionism and conflict theory. These characterise medical sociology over the last 30 years. They elucidate more clearly Elinson's own image of medicine and the patient. But none seems to match his standpoint vis-a-vis the medicalisation of care which refrains from citing psychological forces but emphasises the availability of good medical services.

Health Services Accessibility↗
PubMed1989

Influence of ionic and non-ionic radiographic contrast media on the vasomotor tone of epicardial coronary arteries.

The effect of ionic and non-ionic contrast media on the vasomotility of epicardial coronary arteries was investigated in 21 patients during coronary angiography by use of either diatrizoate-76% (10 patients, group A) or iopromide-370 (11 patients, group B). Coronary angiograms were taken in RAO 30 degrees projection before (= reference) and directly after (t0) diagnostic angiography of the left coronary artery (approx. 7 dye injections in approx. 7 min). Additional angiograms in the same projection followed after 1, 3, 6 and 10 min. Mean diameters of angiographically normal coronary segments were analysed with an automatic edge detection system (CAAS). With diatrizoate-76% coronary dilation at t0 averaged 18.9 +/- 6.7% (P less than 0.001); it correlated positively (P less than 0.001) with the number of diagnostic injections performed per min (mean 1.2 +/- 0.3 min-1), and negatively (P less than 0.5) with the time interval between the last diagnostic contrast injection and t0 (mean interval 73 +/- 35 s). Coronary dilation was unchanged 1 min after t0 (18.3 +/- 5.4%, P less than 0.001) and was still present after 6 min (6.2 +/- 4.6%, P less than 0.01). With iopromide-370 coronary dilation at t0 was mild (5.4 +/- 4.3%; P less than 0.05); the subsequent injections led to minimal insignificant dilation. It is concluded that in quantitative angiographic studies on changes in coronary vasomotor tone repeated coronary angiograms should be taken with non-ionic contrast media; furthermore adequate injection intervals of greater than 3 min should be observed.

Adult↗
PubMed1988

[Comparison of high and low osmolar roentgen contrast media in quantitative coronary angiography].

In 48 patients undergoing diagnostic coronary angiography changes of mean diameters of angiographically "normal" coronary segments after intracoronary injections of diatrizoate 76% or iopromide 370 performed in different intervals, were analyzed with a computer-assisted contour detection system (CAAS). Four study protocols were applied, differing in respect to the type of contrast medium administered and/or to the timing of the reference- and control-angiograms in the course of diagnostic coronary angiography. Coronary angiograms in identical projections were performed before (= reference) and directly after (1. control = C1) diagnostic angiography of the left coronary artery by injection of either diatrizoate 76% (group 1, 10 patients) or iopromide 370 (group II, 11 patients). Additional coronary angiograms were performed 1, 3, 6, and 10 min after C1. During diagnostic angiography in either group about eight dye injections were performed in about seven min. With diatrizoate 76% a significant coronary dilation averaging 18.9 +/- 6.7% (p less than 0.001) was observed at C1, depending on the number of diagnostic dye injections performed per min (mean 1.2 +/- 0.3) and on the interval between the last diagnostic injection and C1 (mean 73 +/- 35 s). Coronary dilation persisted up to the sixth minute (6.2 +/- 4.6%, p less than 0.01). With iopromide 370 a small but significant coronary dilation was observed merely at C1 (5.8 +/- 4.3%, p less than 0.05). In two other studies coronary angiograms were performed in identical projections immediately following complete diagnostic coronary angiography (reference) and in addition after 3, 4, 5, 6, 10, and 20 min (group III, 18 patients) and after 10, 20, and 30 min, respectively (group IV, 9 patients) by administration of diatrizoate 76% as the only contrast medium. Short injection intervals (1 min) resulted in a mild coronary dilation (mean up to 2.4 +/- 4.1% compared to reference; p less than 0.05), longer intervals (3-10 min) resulted in a marked diameter reduction (averaging up to -9.7 +/- 9%; p less than 0.05), probably a consequence of the return of coronary vasomotor tone to baseline levels. These results suggest that in quantitative coronary angiographic studies (e.g., testing coronary vasomotility) non-ionic contrast media should preferably be applied, and adequate injection intervals (greater than 2 min) are mandatory. In intervention- and follow-up studies based on repeated coronary angiograms dye-induced changes of coronary vasomotor tone can be avoided by premedication with vasodilating drugs, e.g. nitrates, and/or calcium antagonists.

Adult↗
PubMed1983

Rheumatoid factor-negative arthritis, especially ankylosing spondylitis, and infections of the male urogenital tract.

146 men with rheumatoid factor-negative (sero-negative) arthritis, i.e., 97 patients with ankylosing spondylitis, 36 patients with Reiter's syndrome, and 13 patients with reactive arthritis, were examined for infections of the urogenital tract by following recently established criteria. 74 patients (50.7%) had infections of the male adnexes: 3 patients suffered from balanitis, 14 patients from urethritis, 49 patients from prostatitis, 1 patient from epididymitis, and 7 patients from urinary tract infection. Balanitis and urethritis were almost exclusively associated with Reiter's syndrome. In 37 of 97 patients with ankylosing spondylitis, a urogenital tract infection, mainly a prostatitis (31 patients), was detected. The microorganisms isolated most frequently from patients suffering from urethritis and prostatitis, were Chlamydia trachomatis and Ureaplasma urealyticum.

Arthritis↗
PubMed1980

A novel method for the determination of electrical potentials across cellular membranes. II. Membrane potentials of Acholeplasmas, Mycoplasmas, Streptococci and erythrocytes.

The membrane potentials of Acholeplasma laidlawii, Mycoplasma mycoides subsp. capri, Mycoplasma gallisepticum, Streptococcus faecalis and human erythrocytes have been determined by applying a novel technique. The membrane potentials were calculated simply from potassium concentrations determined by atomic absorption spectroscopy, and gravimetry. The versatility of the new technique is demonstrated by comparing our results with data obtained by different techniques.

Acholeplasma laidlawii↗
PubMed1977

Localization of a phosphoglycolipid in Mycoplasma membranes using specific anti-lipid-antibodies.

A phosphoglycolipid, presumably identical to glyceryl-phosphoryldiglycosyl diglyceride, is the main component of the membrane glycolipids of Mycoplasma mycoides subsp. capri. It is immunologically active. Anti-phosphoglycolipid antibodies were induced in rabbits by intravenous injection of the flocculated complexes of methylated bovine serum albumin with a mixture of the phosphoglycolipid and the auxiliary lipids, phosphatidyl-choline and cholesterol. The specificities of the antibodies directed against the phosphoglycolipid, are due to both the phosphate and carbohydrate moieties of the lipid molecule. Anti-phosphoglycolipid antibodies were detected in the sera of rabbits intravenously immunized with intact M. mycoides subsp. capri. The intravenous method of immunization was chosen in order to select for a response to surface antigenic determinants. Anti-phosphoglycolipid antibodies specifically reacted with intact organisms and isolated membranes of M. mycoides subsp. capri, as shown by complement fixation and agglutination tests. The antigenic determinants of the phosphoglycolipid are mainly located on the outer membrane surface. It is concluded that the antigenic determinants of the phosphoglycolipid in intact M. mycoides subsp. capri significantly contribute to the surface architecture of mycoplasma membranes.

Acholeplasma laidlawii↗
PubMed1977

Ultrastructural and cytochemical studies on anionic surface sites of Mycoplasma membranes.

Negatively charged, chemical groups on the surfaces of mycoplasma membranes were studied in the electron microscope by staining with positively charged ferric oxide hydrosols in the acetic acid (AI-reagent) or propanoic acid (PI-reagent), respectively. The technique of thin sectioning was used. With the AI-reagent, no significant binding of the ferric oxide particles was observed on the mycoplasma membranes. With the lipophilic PI-reagent, the membrane surfaces of M. mycoides subsp. capri, M. mycoides subsp. mycoides, M. gallisepticum, and Acholeplasma laidlawii were heavily stained with focal aggregates of iron granules. M. hominis did not bind the label. Prior chemical and enzymatic treatments indicate that the cationic ferric oxide particles in propanoic acid interact with negatively charged, presumably lipid phosphate groups exposed on the surfaces of mycoplasma membranes.

Anions↗
PubMed1976

Ultrastructural visualization of anionic sites on mycoplasma membranes by polycationic ferritin.

Anionic sites on mycoplasma membranes were visualized in the electron microscope by a polycationized ferritin derivative. The technique of thin sectioning was used. Staining prior to fixation led to clustering of ferritin granules on the mycoplasma cell surface. On glutaraldehyde-fixed Mycoplasma mycoides subsp. capri, M. gallisepticum, M. pneumoniae, and Acholeplasma laidlawii, the anionic sites were uniformly distributed over the entire membrane surface. M. hominis did not bind the polycationic ferritin label. Chemical and enzymatic treatments of the mycoplasmas indicated that the anionic sites may be lipid phosphate groups. Isolated M. mycoides subsp. capri membranes were labeled exclusively on only one membrane surface, presumably the outer one. Liposomes prepared from diphosphatidylglycerol and phosphatidylcholine were also labeled by the polycationic ferritin.

Acholeplasma laidlawii↗