Search PubMed⌕ Search

Biomedical subjects

P Neumann

Publications and source records attributed to P Neumann.

At least 127 records · Page 7Linked to original sources
PubMed1983

The mechanism of intracardiac shunting in the lizard Varanus exanthematicus.

Intracardiac shunting was studied in unanaesthetized and unrestrained specimens of Varanus exanthematicus by simultaneous injection of radioactively labelled microspheres (15 micron) into the right and left atria. Lung ventilation was monitored by intratracheal pneumotachography. It was found that intracardiac shunting was not significantly affected by the spontaneously occurring periods of ventilation and apnoea: the right-to-left shunt averaged 29 and 31%, respectively, and the left-to-right shunt was 11% in both conditions. The observed shunting, although rather constant with time and independent of the ventilatory state, varied in different individuals. Anatomical studies and intracardiac pressure measurements revealed that, in spite of crocodilian-like systolic pressure separation between pulmonary and systemic circulation (based on the muscular ridge, 'Muskelleiste', between cavum venosum and cavum pulmonale), the cavum venosum is shared by both the pulmonary and the systemic circulation. Intracardiac shunting appears to be mainly due to wash-out of the cavum venosum: blood remaining in this chamber at the end of systole (oxygenated) or at the end of diastole (deoxygenated) is washed into the respective 'inadequate' vascular bed during the next half-cycle of heart action. Thus the extent of intracardiac shunting is expected to depend primarily on the volume and the changes in volume of the cavum venosum during the cardiac cycle.

Animals↗
PubMed1983

Nitrates in aortic valve disease: acute and chronic effects.

The beneficial effect of Nitroglycerin (NTG) on myocardial oxygen-supply-demand ratio in severe aortic stenosis has been already demonstrated. But the chronic administration of isosorbide dinitrate (ISDN) does not reduce the increase in left ventricular filling pressures during exercise. Therefore in severe aortic stenosis, the effects of chronic nitrate administration on left ventricular hemodynamics during exercise do not correspond to the beneficial acute effects of NTG. In aortic insufficiency, sublingual NTG has only minor effects on left ventricular volumes, heart rate and cardiac output. A moderate reduction in pressures results in a significant reduction of wall stress, while there is no major change in regurgitant fraction.

Aortic Valve Insufficiency↗
PubMed1983

[Prognostic value of thallium scintigraphy in diagnostic problem cases].

Quantitative myocardial scintigraphy was performed in 40 patients with a medium prevalence of coronary artery disease (CAD), i.e. in cases with diagnostic difficulties. The results were compared with those of coronary angiography and ventriculography performed within 6 months thereafter. Sensitivity of scintigraphy in 16 patients with CAD was 88% and specificity in 14 individuals without heart disease was 93%. But in 10 patients with non-coronary heart disease specificity decreased to 30%. Scintigraphic evidence of ischemia increased specificity to nearly 100% including patients with non-coronary heart disease but sensitivity was reduced to 69%. The results demonstrate that myocardial scintigraphy with 201Tl is useful in cases with suspected CAD if diagnostic difficulties arise during the early phase of investigation. But there are limitations due to a rather high prevalence of non-coronary heart disease in such groups.

Adult↗
PubMed1982

Escherichia coli pneumonia in the elderly with reference to the role of E. coli K1 capsular polysaccharide antigen.

Escherichia coli pneumonia occurred in 17 elderly patients over a two-year period. All cases were documented by transtracheal aspiration. Six of the 17 E. coli organisms causing pneumonia contained K1 capsular polysaccharide. E. coli K1 organisms did not appear to be more virulent than non-K1 strains as measured by incidence of bacteremia, shock and death. E. coli K1 pneumonia was usually community- acquired (five of six cases) and occurred in patients with a prior history of urinary infection. Non-K1 E. coli pneumonia occurred in the hospital setting in eight of 11 patients, and a gastrointestinal source of infection was likely in five patients. All patients were treated with appropriate initial antibiotic therapy, and 71 percent of patients survived.

Aged↗
PubMed1982

Body composition measurements in normal man: the potassium, sodium, sulfate and tritium spaces in 58 adults.

The aqueous phase of total body composition varies with sex, and changes with age, necessitating age, sex and method-specific normal values. Consensus has developed for the methods most suited to clinical studies. 3H20 for water, 35SO4 for ECW, 24Na for NAc, and 40K for body potassium were used in 58 normal volunteers aged 19-80, 30 men and 28 women. This report shows significant age regressions in both sexes for total body water and intracellular water, and for both Na and K when referenced to body water. Combination of these findings with the highly age related decrease in total body potassium confirms previous studies that body cell mass decreases with age. Intracellular K+ and Na+ at the zero age intercept are 130 and 14.5 for males, and 124 and 24mEq/1 for females respectively. Secular decrease in K+ and increase in Na+ concentrations in the average cell are suggested although not established. Values for normal body composition, in subjects healthy by all available criteria are in some instances age and sex dependent, but in all parameters except fat show wide normal range (SD = 7% of mean) which derive more from biological variation than from limitations of measurement precision. However, use of body water rather than weight succeeds in narrowing this wide range, and is a more logical denominator which is readily subject to accurate measurement. In serial studies of the same subject, significant changes can be measured which are well within the normal range.

Adult↗
PubMed1982

The forearm ischaemic work test--hazardous to McArdle patients?

A 57-year-old patient suffering from late-onset McArdle's disease developed myoglobinaemia, massive myoglobinuria and marked serum creatine kinase elevation subsequent to a routinely performed forearm ischaemic work test. Twenty hours after the test, enhancement of 99mTc methylene-diphosphonate activity was demonstrated exclusively in the tested forearm. It is concluded that the forearm ischaemic work test is potentially hazardous to McArdle patients, as it might induce myoglobinuria sufficient to result in acute myoglobinuric renal failure.

Exercise Test↗
PubMed1979

[Androgen secreting adrenal cortex tumors].

Endokrine active tumours of the adrenal cortex are rare diseases in man. Benign as well as malignant tumours of the adrenal cortex can alone excrete cortisol, aldosterone, androgens or oestrogens. More frequent are, however, tumours with a mixed incretion. Publications about tumours forming sexual hormones are above all descriptions of individual cases. After a short explanation of the most important clinical, diagnostic and therapeutic aspects on androgen-producing tumours of the adrenal cortex four own cases are discussed.

Adrenal Cortex Neoplasms↗
PubMed1977

[Serum digoxin concentration: dependence on body weight and age].

In patients of a cardiological practice, 121 digoxin serum concentrations were determined by radioimmunoassay (RIA). Some drugs were suspected of interfering with the RIA or with the pharmacokinetics of digoxin. Patients having such additional drugs or patients with elevated serum creatinine were not included. The daily maintenance dose of digoxin was roughly adjusted to body weight. Patients with 0.5 mg digoxin daily showed unexpectedly low serum digoxin levels not fully explained by the relatively high body weight. This dose group was not included in the following correlations. At a maintenance dose of 0.25 and 0.375 mg digoxin and in the age groups 40-69 years (n = 66) there was an approximately inverse proportionality between serum digoxin concentration (per 0.25 mg digoxin daily) and body weight. When all age classes from 20 to 89 years were included (n = 96), a week positive correlation between serum digoxin concentration (per 0.25 mg digoxin daily and per 69.28 kg body weight) and age was found. A similar positive correlation resulted between serum digoxin concentration (per 0.25 mg digoxin daily) and the reciprocal of the nomographically determined creatinine clearance, always within the normal serum creatinine range. Based on these correlations, two simplified formulas are presented to predict the serum concentration and therapeutic maintenance dose of digoxin. The formulas are valid for the normal serum creatinine range and for digoxin tablets of optimal bioavailability.

Adult↗
PubMed1977

[The psychological approach in cardiovascular epidemiology].

It is quite generally accepted that a certain personality profile long precedes the first manifestations of coronary disease. However the essential traits and above all their place amongst other risk factors remain controversial. The authors undertook a prospective study involving three male populations grouping 2147 adult subjects. Amongst the questions considered, there was the choice of a simple a quick psychological approach applicable to a population ranging over all cultural levels. The study shows that the Bortner auto-transference scale fulfils all these requirements. Thus a given type of behaviour may be analysed as a risk factor, in the same way as various examinations such a blood pressure or cholesterol level.

Adult↗
PubMed1977

[Determination of 11-hydroxycorticosteroids in stress-evoking interventions as an endocrinological test].

Determinations of the 11-hydroxycorticosteroids (11-OHCS) in intervention evoking stress proved as advantageous method for the estimation of the ACTH-reserve. After pneumencephalography or transethmoidal-transsphenoidal operations of the hypophysis intensive increase of 11-OHCS in the plasma and urine were observed, when the ACTH-reserve was intact. The investigations give the possibility of renouncing additional special functional tests.

11-Hydroxycorticosteroids↗