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Biomedical subjects

C Schönborn

Publications and source records attributed to C Schönborn.

At least 19 recordsLinked to original sources
PubMed2001

Stability of enhanced biological phosphorus removal and composition of polyphosphate granules.

The influence of varying Ca- and Mg-concentration of the influent wastewater on the enhanced biological phosphorus removal was investigated in an anaerobic-aerobic bench-scale plant. The artificial enhancement of the Mg-concentration in the influent from 15 to 24 mg l(-1) and 31 mg l(-1), respectively, caused a raise of the mean P-removal efficiency from 85 to 97%. The P-elimination was very stable in time. A chemical precipitation of magnesium ammonium phosphate could be excluded. The elemental composition of polyphosphate granules was investigated by electron microscopy and energy dispersive X-ray spectroscopy. The elements Ca, Mg and K were the principal metal components of polyphosphate granules. Concerning the metal composition, different types of granules could be distinguished. The quantitative ratios of Ca, Mg and K varied in dependence on the influent concentration of these metals. A relation between the Mg/Ca-ratio of the granules and the efficiency of enhanced biological phosphorus removal can be supposed.

Calcium↗
PubMed1994

Cyclic AMP formation in Tetrahymena pyriformis is controlled by a K(+)-conductance.

Responses of the cAMP generating system of Tetrahymena to changes in the concentrations of external [K+] or [Ca2+] ions were examined. When Tetrahymena are equilibrated in high [K+] buffers, intracellular levels of cAMP decreased to 40% within 2 h. Hyperpolarization of the cells by dilution of external [K+] to one-eighth of its original concentration instantly stimulated intracellular cAMP formation. Manipulations of the K+ resting conductance of Tetrahymena by equilibration in buffers of different K+ content greatly affected the responsivity of the adenylyl cyclase. Hyperpolarization of the cell by addition of Ca2+ also resulted in a rapid generation of cAMP. Blockade of K+ conductances by the K+ channel blockers tetraethylammonium, quinine, and Cs+, dose-dependently inhibited hyperpolarization-stimulated cAMP formation. The data indicate that a hyperpolarization-activated K+ current is directly coupled to adenylyl cyclase regulation.

Animals↗
PubMed1990

[Effect of pepstatin A on Candida albicans infection in the mouse].

The intravenous injection of 10(6) to 10(7) Candida albicans cells revealed to be a reliable model in mice produce infections of the kidney. Higher germ contents could be yielded in the kidney after the application of protease positive Candida-strains as compared to protease negative ones. Additionally, after the infection with protease positive strains a proteolytic activity could be found in the kidney homogenates in vitro on casein plates. The modulation of this Candida infection by pepstatin A, an inhibitor of extracellular yeast proteases in vitro, has also been studied in the same mice model in vivo. The growth rate of Candida albicans has been measured in the left kidney by counting the germ content as described by Haenel. Infections could be reduced after single doses of 120 micrograms pepstatin A contrary to 60 micrograms pepstatin A. The same was with three doses of 180 micrograms at 24 h intervals. This protease inhibitory effect could also be found in kidney homogenates in vitro on casein plates and lasted until 48 h post injection. On the basis of this positive effects on the Candida infection in mice pepstatin A should be considered as an adjuvans in the therapy of severe yeast infections.

Animals↗
PubMed1989

[Infections caused by Candida krusei in newborn infants].

Experiences are described about systemic infections with fungaemia due to Candida krusei in seven newborns treated in a department of neonatology because of several perinatal problems. The origin of this outbreak cold not be established. In six patients the infection was early detected and successfully treated with miconazole and/or ketoconazole, all six newborns recovered. Infections due to Candida krusei are extremely rare in humans. This report demonstrates the clinical picture of this infection in newborns.

Antifungal Agents↗
PubMed1989

[The long-time survival of dermatophytes and moulds under paraffin oil].

Preservation under sterilized paraffin oil is a suitable method for the long-time maintenance of fungus strains in a medical-mycological laboratory. 140 strains of dermatophytes and moulds were checked for their viability by subculturing them after 2-15 year-storage under paraffin oil without changing the medium in the meantime. Nearly 50% of all strains remained alive more than 10 years. An average survival of 8 1/2 years is observed for all groups of fungi investigated (dermatophytes, Zygomycetes, Aspergillus, Scopulariopsis, and several Fungi imperfecti). Subculturing after 5-6 years results in a minimal rate of non-viability. The technically simple paraffin oil method is therefore, at least of the same value for the storage of fungal cultures as other more complicated procedures.

Arthrodermataceae↗
PubMed1986

[Chronic mucocutaneous candida mycosis (CMCC) caused by a T-cell defect].

It is reported on a 42-year-old book-keeper with the granulomatous variant of the chronic mucocutaneous candidiasis which could be followed up for 28 years. The intensive systemic treatment with nystatin, 5-fluorocytosin and miconazol combined with the subcutaneous injection of transfer-factor and the local application of ointments containing nystatin and clotrimazol did not only lead to the complete clearing of the lesions (4 years without any relapse), but also to the normalization of the T-lymphocyte count and the reconstitution of the formerly negative delayed type skin reactivity to candidin.

Adult↗
PubMed1984

[Studies on the mycotic and bacterial risk of contamination and the use of nipagin in the artificial insemination of cryosperm].

Primary bacterial and mycological contamination was studied in random human ejaculates. After various phases of cryopreservation secondary microbiological contamination was investigated. Furthermore, semen samples of several donors were inoculated with suspension of different concentrations of yeasts and with the test bacteria Escherichia coli K12 and Staphylococcus aureus SG 511. Microbiological results were then compared before an after cryopreservation. The cryopreserving process was carried out with and without antibiotics to test the antibacterial effectiveness of antibiotics under these conditions. Moreover, we investigated the usability of a chemical preservative (Nipagin) at cryopreservation. The following results were obtained: 9.8 per cent of samples showed primary mycological contamination (1.9 per cent with Candida albicans). Cryopreservation reduced the concentration of fungi by more than 90 per cent on average. The bacteriological investigations have shown, that with one exception the semen was without pathogenetic bacteria. This situation was altered scarcely during the cryopreserving process (also by use of cryoprotective medium without antibiotics). Out of 25 ejaculates 11 had primary non-pathogenetic bacteria. Test bacteria inoculated into semen were not influenced by the addition of antibiotics to the cryoprotective medium (CPM). Nipagin prevented respectively reduced a bacterial or a mycological contamination of the CPM during a storage of 14 days dependent of nipagin concentration but reduced the motility of human spermatozoa after cryopreservation. The results suggest the conclusion to prefer a portionate storage without nipagin at a temperature of nearly + 1 degree C, thereby the microbiological contamination may be neglected.

Anti-Bacterial Agents↗
PubMed1983

Microbiological investigations on cryopreserved human semen.

Primary mycological contamination was studied in 565 random human ejaculates. After sperm preservation at low temperature, secondary mycological contamination of 55 of the ejaculates was investigated. 25 ejaculates were cryopreserved with and without antibiotics and examined bacteriologically before and after different phases of cryopreservation. Furthermore, semen samples of several donors were inoculated with suspensions of different concentrations of yeasts and with the test bacteria Escherichia coli K 12 and Staphylococcus aureus SG 511. Microbiological results were then compared before and after cryopreservation. The following results were obtained: 1.9.8% of samples showed primary mycological contamination (1.9% with Candida albicans). 2. Cryopreservation reduced the concentration of fungi by more than 90% on average. 3. Only one semen sample was contaminated with bacteria (Staphylococcus aureus haemolyticus and Streptococcus nonhaemolyticus). Non-pathogenic bacteria were found in 11 ejaculates (Micrococcus luteus in 5 samples and Staphylococcus epidermidis in 6 samples), and contamination was largely unaffected by cryopreservation, even in the presence of antibiotics. 4. Test bacteria inoculated into semen were not influenced by the addition of antibiotics to the cryoprotective medium.

Anti-Bacterial Agents↗