Biomedical subjects

A Schmidt

Publications and source records attributed to A Schmidt.

At least 847 records · Page 47Linked to original sources

PubMedDate not supplied

Regulation of a collagen gene promoter by the product of viral mos oncogene.

Oncogenic transformation of cells produces important changes in the biosynthetic pattern of certain cellular proteins. For example, the synthesis of type I collagen in transformed fibroblasts is severely reduced as a result of changes in transcription. Here we report the results of DNA-mediated transfection experiments using recombinant plasmids in which the promoter region of the alpha 2(I) collagen gene is fused to an easily recognizable marker gene, and cell lines expressing the marker gene are isolated. Our data show that the expression of the marker gene fused to the cloned alpha 2(I) collagen promoter is strongly inhibited by v-mos transformation, suggesting that a common mechanism inhibits both the transfected and endogeneous alpha 2(I) collagen promoters.

Animals↗

PubMedDate not supplied

[Operative treatment of ruptures of distal tendon of biceps muscle with a minimally invasive technique using suture anchors--clinical results].

AIM: Ruptures of the distal tendon of the biceps muscle should be treated operatively. A minimally invasive technique and the use of suture anchors may decrease the intraoperative risks. But can satisfactory clinical results be achieved? METHOD: We present the results of a clinical study. Between 1999 and 2005 nine patients were operated for distal biceps tendon avulsion. A minimally invasive operating technique using a suture anchor was established and the technique is described. Rantanen and Orava's score was used to compare clinical and radiological findings. RESULTS: Clinical follow-up was performed at 6 months after operation. In six patients excellent results according to Rantanen and Orava were achieved. No loss of strength was noticed in 6 of 9 cases. Range of motion was unlimited in six patients. In two cases we found heterotopic ossifications. CONCLUSION: On the basis of our results we suggest that minimally invasive surgery using a suture anchor should be performed more often. The technique described leads to results that are comparable to those found in the literature.

Accidents, Occupational↗

PubMedDate not supplied

[Experiences with completely implantable central venous catheter systems].

Over a 30 month-period (1.7.85-7.1.88) 44 totally implantable catheter-systems were used in 41 patients under oncological treatment. Indication was in 40 cases pending, or already started chemotherapy; in one case the indication were multiple transfusions because of aplastic anemia. We used three similar systems of different manufacturers. Our experiences with implantation and care of these systems as well as minor complications are demonstrated.

Adolescent↗

PubMedDate not supplied

Systemic candidiasis in Sprague-Dawley rats.

A reproducible model of a generalized Candida albicans infection was established in rats to allow a precise evaluation of the efficacy of antifungal compounds. In contrast to the intravenous C. albicans model in mice, which serves as a primary model for in vivo efficacy studies of antimycotic compounds, the infectious process in Sprague-Dawley rats is more severely spread into organs other than the kidneys, such as brain, heart, liver, lung, retina and spleen. Apart from a severe granulomatous nephritis beginning 1 day after infection, we observed a severe pneumonitis 3 days after infection with a mass of extravasal erythrocytes in the interstitium and the alveolar space. In addition, multiple nodular lesions could be observed in the brain, heart, liver, retina and spleen on the first day after infection. Lethality was 100% within 1 week, the majority of deaths occurring from 5 to 7 days. Antifungal therapy with amphotericin B or fluconazole led to long-term survival over 4 months, which could not be achieved in mice.

Amphotericin B↗

PubMedDate not supplied

Direct block of the cystic fibrosis transmembrane conductance regulator Cl(-) channel by niflumic acid.

Niflumic acid is widely used to inhibit Ca(2+) -activated Cl(-) channels. However, the chemical structure of niflumic acid resembles that of diphenylamine-2-carboxylate, a drug that inhibits the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel. To investigate how niflumic acid inhibits CFTR Cl(-) channel, we studied recombinant wild-type human CFTR in excised inside-out membrane patches. When added to the intracellular solution, niflumic acid caused a concentration- and voltage-dependent decrease of CFTR Cl(-) current with half-maximal inhibitory concentration (K(i)) of 253 microM and Hill co-efficient of approximately 1, at -50 mV. Niflumic acid inhibition of single CFTR Cl(-) channels was characterized by a very fast, flickery block that decreased dramatically current amplitude without altering open-probability. Consistent with these data, spectral analysis of CFTR Cl(-) currents suggested that channel block by niflumic acid was described by the closed <--> open <--> blocked kinetic scheme with blocker on rate (k(on)) = 13.9 x 10(6) M(-1)s(-1), off rate (k(off))=3348 s(-1) and dissociation constant (K(d)) = 241 microM, at -50 mV. Based on these data, we tested the effects of niflumic acid on transepithelial Cl(-) secretion and cyst growth using type I MDCK epithelial cells. Niflumic acid (200 microM) inhibited cAMP-stimulated, bumetanide-sensitive short-circuit current by 55%. Moreover, the drug potently retarded cyst growth. We conclude that niflumic acid is an open-channel blocker of CFTR that inhibits Cl(-) permeation by plugging the channel pore. It or related agents might be of value in the development of new therapies for autosomal dominant polycystic kidney disease.

Animals↗

PubMedDate not supplied

Comparative virulence of Candida albicans strains in CFW1 mice and Sprague-Dawley rats.

To verify host-species specificities of virulence of Candida albicans in experimental systemic mycoses, 10 ATCC strains of Candida albicans, were compared for their virulence in CFW1 mice and Sprague-Dawley rats. Virulence was parallel in mice and rats, four strains were avirulent (ATCC 10231, 18804, 38245, 44831), one strain had an intermediate virulence (ATCC 32354), and five strains (ATCC 10261, 44373, 44505, 62342, 90028) were highly virulent in both host species. Infection doses of 2 x 10(6) CFU per mouse and 5 x 10(6) CFU per rat were comparable with respect to mortality of animals within 10 days; this represents a 4 : 1 ratio on the basis of body weight. In Sprague-Dawley rats haemorrhage occurred in infections with all virulent strains which was not observed in CFW1 mice.

Animals↗

PubMedDate not supplied

In vitro susceptibility of Malassezia furfur against azole compounds.

The minimum inhibitory concentrations (MICs) for 30 isolates of Malassezia furfur of four azole compounds-bifonazole, climbazole, clotrimazole and ketoconazole were determined as these substances are used in the topical therapy of M. furfur-associated skin conditions. M. furfur is a lipophilic fungus with complex growth requirements; the MICs were measured in a microdilution test system in modified Leeming-Notman medium by a colorimetric read-out with alamarBlue. The MICs of bifonazole ranged between < 0.06 and 1 microgram ml-1 with an empirical median of 0.06 microgram ml-1 for climbazole the MICs were < 0.06 to 0.5 microgram ml-1 (median < 0.06 microgram ml-1), for clotrimazole < 0.06 to 8 micrograms ml-1 (median 1 microgram ml-1), and for ketoconazole < 0.06 to 0.12 microgram ml-1 (median < 0.06 microgram ml-1). Climbazole and ketoconazole showed similar in vitro activity against M. furfur, with bifonazole having slightly lower, and clotrimazole the lowest in vitro activity. These findings may be explained by the extremely low water solubility of the last two compounds; the results have yet to be correlated with the in vivo efficacy of these substances.

Antifungal Agents↗

PubMedDate not supplied

Relationship of sulfated glycosaminoglycans and cholesterol content in normal and arteriosclerotic human aorta.

Sulfated glycosaminoglycans were extracted from arteriosclerotic and adjacent nonarteriosclerotic areas of human aortas from persons ages 28 to 83 years; the glycosaminoglycans were compared with the cholesterol and triglyceride content of the tissues. Sulfated glycosaminoglycans were isolated after proteolytic digestion of defatted arterial tissue and were quantified after reductive labeling with NaB3H4. The amount of glycosaminoglycans in the aorta increased with the age of the person and the cholesterol content (degree of arteriosclerosis) of the aorta. The proportion of chondroitin sulfate/dermatan sulfate increased significantly with age and cholesterol content, whereas the corresponding amounts of heparan sulfate decreased.

Adult↗

PubMedDate not supplied

Multiple functions of thioredoxins.

Reduced thioredoxins from microbial and plant cells, both of cytoplasmic or chloroplast origin, are interchangeable in stimulating such diverse enzyme activities as ribonucleoside diphosphate reductase (E. coli), PAPS sulfotransferase (Synechococcus), and fructose-1,6-bis-phosphatase (from spinach) in vitro. It is suggested that reduced thioredoxins are unspecific, multifunctional cellular proteins while in contrast the oxidized froms require specific enzymes for their reduction.

Bacterial Proteins↗

PubMedDate not supplied

Formation of cyclic adenosine-3'-5'-monophosphate (cAMP) from adenosine-5'-phosphosulfate (APS) in Chlamydomonas reinhardtii CW 15?

Levels of cyclic adenosine monophosphate (cAMP) have been determined in the green alga Chlamydomonas reinhardtii strain CW 15. In the early exponential growth no cAMP was detected, however, in the middle of the exponential growth phase 2.4 pmol cAMP/mg protein were found and the cAMP level increased to 18.8 pmol/mg protein in the stationary phase. An enzyme fraction has been isolated from Chlamydomonas, which produced cAMP in vitro using adenosine-5'-phosphosulfate (APS) as a substrate. This protein fraction was isolated by ammoniumsulfate precipitation, DEAE-cellulose chromatography and Sephadex-G-100 gel filtration. A solvent system was developed for thin layer chromatography to separate cAMP from APS, adenosine-5'-phosphoramidat (APN), 5'-AMP and adenosine. The product was identified as cAMP by cochromatography, coelectrophoresis, treatment with phosphodiesterase, chromatography on Biorad-columns and by the protein-binding assay. The so far purified protein fraction produced 151 pmol cAMP/mg protein and hour in vitro, using APS as a substrate.

1-Methyl-3-isobutylxanthine↗

PubMedDate not supplied

Ventricular function in Chagas' heart disease.

Invasive and noninvasive methods used to evaluate ventricular function in Chagas's disease are reviewed. The traditional indices of overall ventricular performance reflect the interaction of preload, contractility, afterload and heart rate. Therefore, they are unable to distinguish changes in contractility from modifications of loading conditions. The role of ventricular function as a predictor of mortality in chronic Chagas' heart disease is discussed. Ventricular function abnormalities in patients with indeterminate and digestive forms of Chagas' disease are especially emphasized. Finally, the evidence of early impairment of diastolic performance in digestive forms of Chagas' disease are especially emphasized. Finally, the evidence of early impairment of diastolic performance in patients with Chagas' disease is presented.

Chagas Cardiomyopathy↗

PubMedDate not supplied

The auricular VX2 carcinoma--an animal model for sentinel node concept.

BACKGROUND: Considering the increasing clinical significance of the sentinel node (SN) concept, the applicability of the auricular VX2 carcinoma as an animal model for simulation of the SN concept was evaluated. MATERIALS AND METHODS: By means of blue dye and immunofluorescence-marked colloids, the lymphatic drainage of the auricle was described in 8 New Zealand white (NZW) rabbits. In 28 NZW rabbits, the extent of metastatic spread of auricular VX2 carcinomas after 8, 18, 21, 28 and 32 days of tumor growth was examined. RESULTS: Lymphogenic metastatic spread was limited to the parotideal lymph node functioning as SN for 21 days. The disintegration of the physiologic integrity of the SN leads to metastatic spread in the area of the secondary lymph node station after 28 days of tumor growth with successive hematogenic spreading. CONCLUSION: The auricular VX2 carcinoma in NZW rabbits is an appropriate animal model for simulation of the lymphogenic metastatic spread and the SN concept in HNSCC.

Animals↗

PubMedDate not supplied

[The effect of coupled cardiovascular and respiratory afferent signals on the central processes of human information processing].

On the basis of contemporary knowledge on close functional connections between respiratory and cardiovascular afferents a computerized experimental device was developed by means of which central information processing can be studied in dependence on respiration phase and the level of baroreceptor activity. In all the examined parameters (time of motor reaction of two hands, latency of eye-lid reflex) the greatest changes were observed at maximum baroreceptor activity. These changes were clearly distinguished by direction during the phases of inhalation and exhalation. Such effect is probably based on the fact that the influence of cardiovascular afferents on the level of central activity is modulated in respiration rhythm through the mechanism of breath "gating" of postsynaptic STN structures.

Acoustic Stimulation↗

PubMedDate not supplied