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Biomedical subjects

P Heilmann

Publications and source records attributed to P Heilmann.

At least 55 records · Page 3Linked to original sources
PubMed1987

20-Dihydroisomers of cortisol and cortisone in human urine: excretion rates under different physiological conditions.

The urinary excretion rates of free cortisol and cortisone as well as of their 20-dihydroisomers have been studied in normal subjects under different physiological or pharmacological conditions. For the estimation of steroid excretion rates, a fully automated, liquid-chromatographic method was used. In normal subjects, the median steroid excretion rates of free cortisol, cortisone, 20-alpha-dihydrocortisol, 20-beta-dihydrocortisol, 20-alpha-dihydrocortisone and 20-beta-dihydrocortisone were 6.7, 8.0, 9.8, 5.2, 5.7 and 1.3 mumol/mol creatinine. The excretion rates measured at three different intervals of the day followed a circadian rhythm similar to that known for the cortisol secreting activity of the adrenal gland. After adrenal stimulation by i.v. application of 250 micrograms of tetracosactide hexaacetate, (Synacthen, corticotropin beta 1-24) excretion of urinary cortisol was significantly higher than those of the other steroids. During a 24 h infusion of corticotropin beta 1-24, the excretion rates of cortisol and its C-20 reduced isomers increased to a significantly greater extent than those of cortisone and its C-20 reduced isomers. During a four-hour infusion of hydrocortisone, the relative increase of cortisol excretion was greater than that of the other steroids. During a five-hour infusion of metyrapone at different dosages, the excretion of all steroids decreased in a dose-dependent manner. The present data indicate that the 20-dihydroisomers of cortisol and cortisone in human urine primarily originate from the peripheral metabolism of cortisol rather than from adrenal secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian Rhythm↗
PubMed1987

[Comparative local and systemic immunization against experimentally-induced Bordetella bronchiseptica pneumonia in ICR mice].

It is described the experimental Bordetella bronchiseptica infection via aerosol in ICR mice. 10(6) living bacteria were found in the lung after aerosol challenge with a total of 10(12) CFU. The pneumonias produced in this infection model within 10 days are focal, interstitial and proliferative to a low and medium degree, respectively. They are significantly reduced already by a single i.p. or s.c. immunization. Two vaccinations with inactivated Bordetellae or a temperature sensitive mutant reduce the frequency and severity of the pneumonias, dependent on the administered immunizing dose. The efficacy of two consecutive immunizations via aerosol is comparable to that of two i.p. vaccinations.

Administration, Inhalation↗
PubMed1986

Automated liquid chromatographic determination of the 20-dihydro isomers of cortisol and cortisone in human urine.

A fully automated method for the simultaneous assessment of cortisol, cortisone and their 20-dihydro isomers in human urine is described. On-line sample enrichment, prepurification, focusing and injection are combined with automated high-performance liquid chromatographic separation and quantification. Losses of steroids throughout the total procedure are negligible. Thus, external calibration is feasible for quantification. Coefficients of variation range between 8.7 and 17.0% for inter-assay variability and between 1.3 and 5.2% for intra-assay variability. Assay sensitivity is 15 nmol/l. In normal students, the medians of the relative excretion rates of free 20 alpha-dihydrocortisol, 20 alpha-dihydrocortisone, 20 beta-dihydrocortisol and 20 beta-dihydrocortisone were 10.9, 6.1, 7.7 and 4.4 mumol/mol creatinine. The fully automated feature renders the present method well suited for routine diagnosis of hypercorticoidism.

Autoanalysis↗
PubMed1986

[Local and systemic immunization against experimental infection of mice with Pasteurella multocida].

Model experiments with mice are presented in which the defense against challenge infections has been checked after immunization with various living and killed vaccines of Pasteurella. A temperature sensitive Pasteurella mutant has proved to be superior to inactivated bacteria. It has been established that different routes of administration result in different effects. In this context, intraperitoneal, intramuscular and intratracheal administration have resulted in the highest protection rates, even when combined with oral and aerogeneous immunizations, which are of little efficacy when used exclusively. The importance of a change in the route of administration during repeated immunizations is discussed.

Administration, Intranasal↗
PubMed1984

[Effect of iron on Pasteurella multocida].

Iron is an important factor for growth, virulence and immunogenicity of the species Pasteurella multocida. This has been demonstrated in numerous experiments with bacterial cultures in vitro and immunized and not immunized animals in vivo (mice, piglets, calves). Iron substrates or iron chelators affect in different manner the virulence of P. multocida in vivo, depending on chemical character of the given compounds, their dose, route and time of application, and also depending on the host. P. multocida has an up to time unknown iron transport system, which can acquire the essential iron from physiological substances, such as heme, ferritine, transferrine, lactoferrine etc. This conclusion results from in vitro experiments with growing cultures, with insertion of radioactive iron (Fe-59) from different sources, and with iron solubilization in neutral pH ranges. In the same way, the iron of iron dextran and low molecular iron compounds is available for P. multocida. Iron of unphysiological complexes, potassium ferrocyanide, and ferrocene is unavailable. On the other side such iron chelating agents as nitrilotriacetate, tirone, ferrocene, citrate, EDTA, and apotransferrine do not or only a little affect growth, and such chelators as alpha, alpha'-dipyridyle, phenanthroline and the microbial siderophores deferrioxamin B and enterobactin are inhibitory substances for multiplication of P. multocida. This substances also inhibit the insertion of Fe-59 into the bacterial cell. The conclusion is drawn that neither enterobactin nor deferrioxamine B as typical representatives of phenolate or hydroxamate siderophores take part in Fe-transport of P. multocida.

Animals↗