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Biomedical subjects

U Smidt

Publications and source records attributed to U Smidt.

At least 55 records · Page 3Linked to original sources
PubMed1978

[The judgement of collagen metabolism by hydroxyproline in plasma and urine and plasma collagenic peptidase under different diet (author's transl)].

In 34 subjects--coal workers with pneumoconiosis, patients with collagenic diseases and healthy subjects--the daily urinary excretion of hydroxyproline (HP) and the plasma concentrations of HP and of collagenic peptidase have been measured during one week under HP-free and HP-enriched diet. It is shown that a 24-hour period of HP-free diet is necessary and sufficient before collecting urine or plasma for diet independent measurements of total or non-protein bound HP. Concentrations in plasma correlate well with the amounts excreted in urine. Collagenic peptidase is independent from the diet and well suited for assessment of the activity of the metabolism of collagene. There are no differences between healthy subjects and coal workers with pneumoconiosis.

Adult↗
PubMed1978

[Relation between actual barometric pressure at sea level and alveolar and arterial pO2: correlations in 3,054 coal workers with and without pneumoconiosis (author's transl)].

The correlation between barometric pressure and arterial oxygen pressure has been investigated in 3,054 coal miners. Furthermore, the correlation between alveolar oxygen pressure and alveolar-arterial oxygen pressure difference and barometric pressure has been investigated in 1,669 coal miners. For low and for high pO2a there are significant correlations to barometric pressure, in particular for the young age groups. PO2A and AaDO2 show closer correlations to barometric pressure in the middle range of pO2a (65--84 mm Hg). This points to different regulating mechanisms. A correction with a uniform factor is not possible and, for clinical purposes, unnecessary, since the influence of changing barometric pressure on pO2a is only about 1--3 mm Hg.

Age Factors↗
PubMed1978

[Respiratory gas exchange during breathing of O2 in different inert gases (author's transl)].

In 15 patients with chronic bronchitis with or without emphysema breathing of room air was compared with breathing of 20.9% O2 in helium and in argon. Minute ventilation and alveolar ventilation showed no differences, whereas the alveolar and arterial pO2 and PCO2 showed an improvement of the CO2 gas exchange and a deterioration of the O2 gas exchange. This contradictory behaviour cannot be explained by shunts or inhomogeneities or influence of gaseous or alveolo-capillary diffusion. Perhaps the physicochemical properties of the alveolo-capillary membrane change by the depletion of nitrogen. The recommendation of helium-oxygen breathing, proposed by other authors for patients with obstructive airway diseases, cannot be supported, when the gas exchange for O2 is deteriorated.

Adult↗
PubMed1977

[Acid-base balance immediately after administration of an oral contraceptive (author's transl)].

An increase in breathing activity has often been described for the secretory phase of the menstrual cycle, for gravidity and after intramuscular application of corpus luteum and follicle hormone. The reason for this has been assumed to be a direct interaction of the hormones in the respiratory center. A shortly published paper dealing with 50 women under long-term treatment with a combination of oestrogenes and gestagenes for oral contraception leads the author to the assumption, that a metabolic acidosis is the primary reaction, followed by an increase in breathing activity for respiratory compensation. In a long-term study it is difficult to differentiate between primary and secondary effects. Therefore in the present experiments arterial blood has been analyzed for PaO2, PaCO2, pH and hemoglobin in 49 subjects on day 1 without hormone administration and on day 2 prior to (9.00 a.m.) after (11.00 a.m., 1.00 p.m., 4.00 p.m.) administration of a combination of oestrogene and gestagene. From the measured values O2-saturation, standard-bicarbonate, buffer bases and base excess have been calculated by the Thews nomogram. By comparison of the results before and after hormone administration it was shown, that the primary effect is a metabolic acidosis, partly compensated during the next 7 h by respiratory adaptation. There is no indication for a primary respiratory alkalosis.

Acid-Base Equilibrium↗
PubMed1976

Respiratory gas exchange and lung perfusion in man during and after head-out water immersion.

The respiratory gas exchange for O2, CO2, and CO has been studied in nine healthy male subjects before, during, and after head-out water immersion. Distribution of lung perfusion and ventilation were determined by quantitative double nuclide scintigraphy (131J and 99mTc) and by argon washout, respectively. The well-known decrease of PaO2 and increase of AaDO2 during immersion is accompanied by a decrease of the CO-transfer factor. Ventilation in relation to functional residual volume does not change significantly, whereas distribution of lung perfusion becomes more even, with an increase in the apical lung zones. Immediately after the end of immersion, PaO2 increases rapidly, exceeding the initial value under dry conditions. At the same time, lung perfusion is shifted markedly more towards the basal lung regions, exceeding the gravity-induced blood pooling in the erect subject under dry conditions. The observed changes tend to normalize within 2 min. The changes of respiratory gas exchange during and immediately after immersion can be explained by changes of the inequality of the ventilation-perfusion ratios.

Adult↗