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Biomedical subjects

K Schaller

Publications and source records attributed to K Schaller.

At least 19 recordsLinked to original sources
PubMed1992

Positive interaction of nikkomycins and azoles against Candida albicans in vitro and in vivo.

Nikkomycins X and Z (NZ), competitive inhibitors of fungal chitin synthetase, were combined with azoles in a series of in vitro checkerboard assays to test for synergism against Candida spp. All combinations of nikkomycins and azoles tested resulted in marked synergistic activity against an isolate of Candida albicans, with fractional inhibitory concentration indices ranging from 0.016 to 0.28. No synergistic effect was demonstrable with isolates of C. tropicalis, C. parapsilosis, or C. krusei, though results for the latter two were suggestive of an additive effect. In survival models of mice infected intravenously with C. albicans, NZ administered singly in doses ranging from 5 to 50 mg/kg of body weight twice a day was able to delay the onset of mortality but showed no dose-response effect. The combination of NZ and the azole R 3783 administered orally in a ratio of 8:1 to 40:1 or greater (wt/wt) enhanced survival better than did the drugs given individually, but this effect was less evident for combinations involving fluconazole. In short-term organ load assays with outbred mice infected intravenously with C. albicans, high ratios of NZ to R 3783 reduced the CFU per gram in kidneys more significantly than did the drugs individually. Statistically significant reductions were not seen for short-term fungal burden assays using combinations of NZ and fluconazole in outbred mice or in inbred mice more susceptible to candidiasis. In a model of rat vaginal candidiasis, the combination of NZ and R 3783 administered either orally or vaginally was more effective than the drugs used singly. Thus, under certain conditions, combination therapy with nikkomycin and select azoles may offer promise for an increased therapeutic effect in candidiasis.

Aminoglycosides↗
PubMed1991

[Two cases of laryngeal sac suppuration in orangutans in the Münster Zoological Park (all weather zoo)].

It is reported on two cases of pyosis of the laryngeal pouch in two Orang-outangs. In one case the disorder led to the death of the animal within three months, while the other was treated surgically and the pus drained. The discussion is based on available literature. The masked feature of the disorder and its insidious progress is pointed out. The cause is attributed to hereditary disposition and faulty zoo-keeping.

Animals↗
PubMed1991

Segregation of Na(+)-channel gene expression during neuronal-glial branching of a rat PNS-derived stem cell line, RT4-AC.

RT4 is a family of cell lines isolated from an ethylnitrosourea-induced rat peripheral neurotumor. RT4-AC cells express both excitable membrane and glial cell properties. In a process called cell-type conversion, RT4-AC cells segregate these properties to generate three distinct derivative cell types which have been classified as either neuronal (RT4-E and RT4-B) or glial (RT4-D). In this report we demonstrate that: (1) upon cell-type conversion, Na(+)-channel mRNA expression segregates primarily with the RT4 neuronal derivatives, (2) the SkM2 Na(+)-channel gene, which was originally isolated from rat muscle cDNA libraries, is the predominant gene expressed by the RT4 neuronal derivatives, (3) the three rat brain Na(+)-channel genes I, II, and III and the muscle-derived SkM1 gene are not the principal Na(+)-channel genes involved in the segregation, although very low levels of message of these genes are detected, and (4) the RT4 glial derivative expresses slightly higher levels of message from rat brain genes I and II than the neuronal derivatives. Since the RT4 cell lines were derived from a peripheral neurotumor these results present the possibility that the SkM2 gene may be important in vivo in the rat peripheral nervous system.

Animals↗
PubMed1990

[Effect of long-term therapy with prazosin/propranolol on blood pressure and cardiopulmonary function in essential hypertension].

In 25 hypertensives (42 +/- years), predominantly at stage I according to WHO-criteria, by the application of daily 5 +/- 4 mg prazosine and as combination of 9 +/- 6 mg with 73 +/- 31 mg propranolol the blood pressure normalized itself from on an average 183 to 148 mgHg systolically and 113 to 93 mgHg diastolically. In a long-term experiment confirmable also echocardiographically prazosine alone decreased the afterload of the heart in an unchanged high energy requirement at rest, and in a submaximal ergostasis the aerobic metabolic situation deteriorated. This could again be balanced by the combination with propranolol, whereby oxygen pulse, product of the pressure frequency and PWC 130 even improved. Function and size of the left ventricle remained echocardiographically uninfluenced in the two forms of therapy.

Adult↗
PubMed1977

[Dependence of lactate and heart rate in ergometer-, running- and swimming stress and its use for the preparation of individual conditioning programs for patients with myocardial infarct in rehabilitation phase III].

The dependence of the heart rate of 25 patients between 6th and 12th month after myocardial infarction on the lactate deflection during bicycle ergometry was compared with values being measured in physical conditioning in gymnasium and in indoor swimming-bath. There were found congruent statements in all three types of stress. The immediate comparison of patients undergoing rehabilitation who realized a gymnasium and swimming program simultaneously, showed no differences in lactate deflection and heart rate, too. So heart rates of equal level signal the production of equal metabolic training irritations in the three types of stress being tested. Moreover it was to be ascertained that the optimum intensity of the physical conditioning of patients with myocardial infarction is reached with a lactate deflection of 2,5 to 4,0 muMol/1, appropriate to a heart rate of 104 to 120 beats every minute resp. an efficiency of 70% of the submaximum aerobic capacity.

Conditioning, Psychological↗
PubMed1977

[Dependence of lactate on pulse rate, performance and cardiac volume performance quotient in rehabilitated myocardial infarct patients during bicycle ergometry].

All males of the district Cottbus who suffered from an acute myocardial infarction between 1 June 1973 and 30 June 1974 and survived the first rehabilitation phase of a definite myocardial infarction were included in the study. Their arterial lactate level, the oxygen intake, the heart rate and heart size were determined by means of standardized ergometry and radiology. Patients who had performed a rehabilitation training programme showed a higher efficiency and equal values of lactate level and heart rate compared with the patients without training programme. A close correlation also existed between lactate level and heart rate. There was no dependence on the age of the patient or the degree of heart insufficiency. These results allow to conclude that the lactate level can be used for the determination of the training intensity of patients after an acute myocardial infarction.

Aged↗
PubMed1976

Colicin E2 is DNA endonuclease.

Colicin E2 purified by conventional methods contains a tightly bound low-molecular-weight protein, as has been found with purified colicin E3 [Jakes,N.&Zinder,N.D.(1974) Proc. Natl. Acad. Sci. USA 71, 3380-3384]. Such E2 preparations do not cause DNA cleavage in vitro. After separation from the low-molecular-weight protein, colicin E2 retained the original in vivo killing activity, and in addition showed a high activity in vitro in cleaving various DNA molecules, such as a ColE1 hybrid plasmid and DNAs from Escherichia coli, lambda phage, chiX174 phage, and simian virus 40. The low-molecular-weight protein ("E2-immunity protein") specifically prevented this in vitro DNA cleavage reaction, i.e., had an "immunity function." The results demonstrate that colicin E2 itself is a DNA endonuclease and explain the in vivo effects caused by E2 in sensitive cells as well as the mechanism of immunity in E2-colicinogenic cells.

Colicins↗
PubMed1976

Thiamine absorption in the rat. IV. Effects of caffeic acid (3,4-dihydroxycinnamic acid) upon absorption and active transport of thiamine.

The effects upon thiamine absorption in-vitro and in-vivo by caffeic acid (a thiamine antagonist isolated from bracken) was studied, partly using 14C-thiamine. It was again shown that caffeic acid reduced the quantity of thiochrome positive thiamine, dependant upon the concentration ratio caffeic acid/thiamine. Caffeic acid was able to pass across the intestinal wall and to exert its antithiamine effect in the serosal incubation fluid. When caffeic acid was present in the mucosal fluid the amount of thiochrome positive thiamine passed to the serosal side was diminished according to the mucosal caffeic acid concentration. In-vitro studies with 14C-thiamine revealed, however, that thiamine modified and turned into a thiochrome negative form by caffeic acid was absorbed similarly to unaffected thiamine. Active transport in-vitro of thiamine was significantly inhibited by the presence of caffeic acid.

Animals↗