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Biomedical subjects

P Hofmann

Publications and source records attributed to P Hofmann.

At least 91 records · Page 5Linked to original sources
PubMed1993

Effect of 17 beta-estradiol on somatic and germ cell subpopulations in the ovary of the newly hatched chick.

The involvement of estrogens in avian ovary differentiation and morphogenesis has been previously demonstrated by several authors. The aim of the present study is to provide evidence regarding which cell subpopulations of the ovary are target cells for 17 beta-estradiol during chick development. White Leghorn chick embryos received 200 ng of the hormone or the vehicle on the chorioallantoic membrane at 11, 13, and 15 days of incubation. Within 24 hr after hatching, the left ovary was processed for total cell count, study of the meiotic prophase of oocytes, and the morphometric evaluation of the cortical and the medullary regions of the ovary. Germ cell number was not modified by the treatment. Similarly, no changes were observed in the stage of the prophase and the cellular area of oocytes. The total number of somatic cells was increased in the newly hatched chick ovary treated with 17 beta-estradiol. The number of undifferentiated cells in the juxtacortical medulla was higher in the treated ovary than in the control group. Moreover, the pregranulosa cells of the cortical region were hypertrophied in the 17 beta-estradiol treated ovary. However, no changes were observed in the typical steroidogenic cells after the estrogen treatment. In conclusion, two subpopulations of somatic cells are estrogen target cells in the prefollicular chicken ovary: the pregranulosa cells of the ovarian cortex and the undifferentiated cells in the juxtacortical medulla.

Allantoin↗
PubMed1993

Correlation between inflection of heart rate/work performance curve and myocardial function in exhausting cycle ergometer exercise.

The heart rate/work performance (fc/W) curve is usually S-shaped but a flattening at the top is not always seen. By means of radionuclide ventricular scintigraphy, the left ventricular ejection fraction (LVEF) of 15 sports students was investigated. The behaviour of the fc/W curve during cycle ergometry with increasing exercise intensities was examined. During exercise, the LVEF showed a distinct initial increase reaching roughly constant values at stress levels below-maximum, and sometimes even falling again. The inflections of the fc/W curve and left ventricular ejection fraction/performance curve (LVEFPC) were calculated from a second degree polynomial fit. From this function, the slopes of the tangents at the points of aerobic threshold and maximum performance were calculated together with the differences of the angles as a measure of the fc/W curve and LVEFPC inflections. It follows that the fc/W curve inflection became less pronounced or was even absent altogether when the decrease in LVEF towards the end of the ergometer exercise became more distinct. A significant negative correlation was found between the existence and extent of the fc/W curve inflection and the stress-dependent myocardial function, expressed as the inflection of the LVEFPC (P < 0.01, r = 0.673). Thus, it would seem that the absence of a fc/W curve inflection was related to a diminished stress-dependent myocardial function.

Adult↗
PubMed1993

[Neuroleptic low-dose long-term strategy and intermittent therapy strategy in chronic schizophrenia--a critical review].

Much effort has been devoted during the past decade in finding new therapeutic approaches to cope with the commonly occurring adverse side effects of long-term neuroleptic maintenance treatment of schizophrenics, such as, in particular, akathisia, parkinsonian symptoms and tardive dyskinesia. Both low-dose maintenance (e.g. long-term treatment at dosages reduced to one-fifth or even less of conventional dosage levels in remitted and stable schizophrenics) and intermittent or-target medication strategies (e.g. discontinuation of neuroleptics in remitted stable chronic schizophrenics, aimed at resuming the medication as soon as prodromal signs of a relapse or actual relapses occur) might eventually imply for many schizophrenics a substantial reduction in total long-term neuroleptic dosages. This may lead to a reduction in the incidence of side effects and to an improvement in social integration. A critical review of the results published so far arrives at the following conclusions: 1. low-dose maintenance therapy is just as effective as a standard dose regimen and even superior to intermittent (target) medication. Especially if the dosage is increased in case of exacerbations; 2. these results are representative for a very small group of patients only, since the study populations were highly selective.

Antipsychotic Agents↗
PubMed1992

Sensitization of rat alveolar macrophages to enhanced TNF-alpha release by in vivo treatment with dexamethasone.

Treatment of rats with dexamethasone rapidly induced a marked weight loss which occurred within 3 days and persisted for several weeks. The cachectic state was paralleled by increased serum levels of triglycerides, albumin, and protein and a strong reduction of blood mononuclear leukocytes. In lung sections, an increased number of mononuclear giant cells was found but no bacteria, fungi, or Pneumocystis carinii organisms. Quite strikingly, alveolar macrophages from dexamethasone-treated rats, but not from control animals, were highly sensitive to LPS and released large amounts of TNF-alpha ex vivo. Also under in vivo conditions, high TNF-alpha serum concentrations were found in dexamethasone-treated but not control rats when examined 1 1/2 hr after an intravenous LPS injection. These data suggest that the glucocorticoid-induced cachexia of rats may be linked, at least in part, to readily inducible TNF-alpha release from primed macrophages.

Animals↗
PubMed1992

Midazolam shortens seizure duration following electroconvulsive therapy.

In an open, prospective clinical trial, midazolam anaesthesia was compared with thiopental (plus suxamethonium chloride as a muscle relaxant) to clinically evaluate the former as an anaesthetic and a muscle relaxant during electroconvulsive therapy (ECT). Twelve depressed patients underwent a course of ECT, receiving midazolam or thiopental anaesthesia alternatively. Significant differences were found in seizure duration between the two anaesthetics. Midazolam shortened the seizures to a duration that was not therapeutically desirable. There were no differences in stimulus parameters between the two groups. The muscle relaxant effect of midazolam failed to provide optimal paralysis. Thus, midazolam anaesthesia offers no advantage over standard anaesthetic agents for ECT.

Adult↗
PubMed1992

Nasal administration of naloxone for detection of opiate dependence.

In clinical trials, nasally applied naloxone was used to identify opiate dependence in humans for the first time. Withdrawal distress was recorded, and pupillary response, pulse rate and blood pressure measured. A significant increase in withdrawal distress and pupillary dilation was observed after nasal administration of 1mg (1mg/400 microliters) naloxone in all subjects who also showed opiate-positive urine samples. In control subjects, no reaction to naloxone was observed. It may be concluded that the nasal route for naloxone administration is as effective as the parenteral route. This test is sensitive enough to identify the physically-dependent opiate user and might have a role in emergency medicine and withdrawal treatment.

Administration, Intranasal↗
PubMed1991

[Use of the heart rate during exercise for the determination of anaerobic threshold in children].

Ethical, economic and other reasons prevent assessment of the anaerobic threshold in children by invasive methods such as estimation of the lactate concentration in blood or ventilation parameters. Conconi developed a non-invasive field test which can be used to assess the anaerobic threshold by analysis of a heart rate curve during a graded load. Although this test was originally used only in adults top sportsmen, it can be applied according to the most recent findings also in children and not only under field conditions but also in the laboratory. By using standard test protocols a high correlation can be obtained with the anaerobic threshold assessed by the lactate method.

Adolescent↗
PubMed1989

[Delusions of parasitic skin infestation in elderly dermatologic patients].

In a study on 21 patients, who had been treated at the Erlangen Dept. Dermat. for delusion of parasitosis during the last 17 years, we compiled catamnestic data, evaluated the personality profiles, and focussed upon the interrelations between the clinical symptoms, the outcome of various psychological tests, and the course of the disease. Our sociographic results agreed well with those of earlier studies (i.e. social isolation, conflicts in or loss of partnership and sexuality). Nearly half of the patients complained about depressive moods which, however, could not be psychometrically proved. In every fifth patient, we detected a propensity to paranoia both clinically and psychopathometrically, indicating the development into paranoic delusion. In general, the patients' aggressiveness was found rather low. Nor were there any hints for organic psychosyndromes in the majority of the patients. We conclude that delusion of parasitosis usually represents a solitary phenomenon of primary psychosis, which can largely be regarded as a monosymptomatic hypochondriac disorder. Successful treatment with neuroleptic drugs depends on a confidential interrelation between patient and physician.

Adult↗
PubMed1989

Origin of p-aminobenzoic acid from chorismic rather than iso-chorismic acid in Enterobacter aerogenes and Streptomyces species.

Enzyme extracts from Enterobacter aerogenes (62-1), Streptomyces aminophilus, and Streptomyces coelicolor were used to investigate the biosynthesis of p-aminobenzoic acid. The enzyme preparations from E. aerogenes and S. aminophilus contained both p-aminobenzoate synthase and iso-chorismate synthase activity, and were able to convert both chorismic and iso-chorismic acid to p-aminobenzoic acid. The apparent KM for chorismic acid was, however, significantly lower than that for iso-chorismic acid, while the Vmax was identical for both substrates in both enzyme systems. The enzyme preparations from S. coelicolor did not contain iso-chorismate synthase activity and p-aminobenzoic acid synthesis took place in this system from chorismic acid only. It is concluded that iso-chorismic acid is not an obligatory intermediate in p-aminobenzoic acid biosynthesis in these organisms.

4-Aminobenzoic Acid↗