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Biomedical subjects

R Hoffmann

Publications and source records attributed to R Hoffmann.

At least 451 records · Page 25Linked to original sources
PubMed1980

Increased phosphatidylinositol synthesis in rat embryo fibroblasts after growth stimulation and its inhibition by delta-hexachlorocyclohexane.

When resting rat embryo fibroblasts are stimulated to grow, a substantial increase in phosphatidylinositol synthesis can be observed. This increase cannot be explained by increased glucose uptake or glycolysis. delta-Hexachlorocyclohexane having the same configuration as myo-inositol, inhibits phosphatidyl inositol synthesis as well as DNA synthesis and mitosis, but has no effect on phosphatidyl choline synthesis. When delta-hexachlorocyclohexane is added to fibroblast cultures during the first hours after stimulation, a delay of DNA synthesis and mitosis compared to uninhibited cultures can be observed. Since delta-hexachlorocyclohexane also inhibits the uptake of nucleotides, hexoses and amino acids, it is suggested that phosphatidylinositol is necessary for the proper functioning of those receptors and carriers which are an essential part of the early cellular processes after growth stimulation, and this role of phosphatidyl-inositol may explain its increased turnover in growing cells. The increased phosphatidylinositol synthesis could not be associated to one of the subcellular fractions. When cells were labeled with [32P]orthophosphate during the first 10 min after growth stimulation and were subsequently separated into cellular fractions such as nuclei, mitochondria, plasma membranes and microsomes, no significant differences in radioactivity of phosphatidylinositol among those fractions could be observed.

Animals↗
PubMed1980

Anatomical distribution of T- and B-lymphocytes in Marek's disease--an immunohistochemical study.

Neural lesions of Marek's disease, Marek's disease tumours in the ovary, liver, and kidney, as well as spleen and bursa of Fabricii of chickens bearing Marek's disease tumorous infiltrations, were examined by a new immunohistochemical technique basing upon Sternbergers unlabelled antibody enzyme method which allows the exact localization of lymphoid cells based on their surface antigens. Type C neural lesions contained T-lymphocytes almost exclusively. Type B neural lesions had relatively high proportions of T- and B-lymphocytes, and severe type A neural lesions possessed one part of heavily labelled T-lymphocytes and a number of cells stained weakly by rabbit-anti-chicken-T-cell-globulin. Tumorous infiltrations had similar characteristics as type A neural lesions. Spleen and interfollicular spaces of bursa of Fabricius were infiltrated by T-lymphocytes.

Animals↗
PubMed1980

Hypothetical strain-free oligoradicals.

Several new classes of oligoradicals free of angle strain are suggested and examined by means of molecular orbital calculations. The collapse products of these hypothetical radicals are highly strained molecules. Various electronic strategies for the stabilization of these oligoradicals have been explored.

Journal Article↗
PubMed1980

[Laparotomy for acute abdomen in larvate depression].

35--40% of psychosomatic disturbances among depressive patients present as abdominal troubles. These are difficult to interpret in the case of larvate depression which manifests itself mainly in the somatic sphere. For the last twenty years, we have noticed an increased incidence of larvate depressions. As a result, patients are often inadequately treated or submitted to surgery. This report is about a 37-year-old female patient who was referred to us with the diagnosis of an acute abdomen. After extensive investigations we were able to rule out as well a mechanical as a reflectory ileus. Nevertheless, the rapid deterioration of her general condition, increasing peritonism and radiological evidence of ileus made us suspect a perforated ulcer with accompanying paralytic ileus and perform an exploratory laparotomy 24 h later. We were very surprised not to discover any abnormal findings at operation. The consultant psychiatrist eventually diagnosed a depression. Up to this date, we have not been able to discover any information about similar patients presenting with such an acute history, even in specialised psychiatric literature. Should one refer such patients with acute abdomen to the psychiatrist before operating?

Abdomen, Acute↗
PubMed1979

[Glomus tumors (author's transl)].

Pathology and clinical picture of glomus tumors are described with emphasis on their location on hand and digits. It is stressed that the knowledge of this rare but extremely painful condition is essential for early treatment. Surgical treatment is standardized and simple.

Aged↗
PubMed1979

[Is the jejunoileal bypass still justified? (author's transl)].

The jejunoileal bypass for the treatment of extreme obesity is being increasingly criticized because of its severe metabolic complications. With the gastric bypass, developed by Mason in 1967, there now exists an operative alternative that is equivalent concerning weight reduction, but does not create such non-physiologic conditions of absorption, and therefore is not burdened with the severe metabolic disturbances of the jejunoileal bypass. Therefore the jejunoileal bypass should not be used any longer for the treatment of obesity.

Diarrhea↗
PubMed1979

The description of structural and temporal characteristics of tonic electrophysiological activity during sleep.

The structural and temporal characteristics of tonic variation among electrophysiological measures during sleep are examined from the point of view of sleep stage scoring procedures and the digital quantification and statistical analysis of these measures. Sleep stage scoring procedures are nominally scaled and therefore less able to index structural and temporal characteristics than are measures derived from digital methods of quantification having the properties of interval or ratio scales. These arguments are illustrated using principal components analysis to describe the structure of tonic covariation among 36 variables derived from the computer analysis of EEG, EMG, and EOG. Three components resulting from the analysis are tentatively named 'slow-fast', 'hemispheric-shift' and 'eyes-activation'. They appear across variations in experimental manipulations such as night time awakenings and also across differences in age and species. The periodic characteristics of the vectors associated with the three components are specified by means of the Fast Fourier transform in combination with digital low pass and band pass filtering. Cycles are found which are both slower and faster than the paradigmatic 90 min ultradian rhythm. These results indicate that currently available techniques of digital and statistical analysis provide new possibilities for research on the electrophysiology and psychophysiology of sleep.

Adolescent↗