Search PubMed⌕ Search

Biomedical subjects

M Horn

Publications and source records attributed to M Horn.

At least 163 records · Page 9Linked to original sources
PubMed1982

Postural changes in pulmonary blood flow in pulmonary hypertension: a noninvasive technique using ventilation-perfusion scans.

To determine whether postural changes in ratio of upper to lower (U:L) zone pulmonary blood flow reflect pulmonary arterial pressures, we used pulmonary perfusion photoscintigraphy to study 12 normal subjects and 10 patients with precapillary pulmonary hypertension (eight classified as "primary" and two as thromboembolic). All patients underwent right-heart catheterization and measurement of pulmonary arterial systolic, diastolic, mean and capillary (wedge) pressures. The distribution of perfusion was then assessed in the supine and erect positions after i.v. injection of technetium-99m-labeled, macroaggregated albumin. Perfusion distribution was corrected for lung volume by xenon-133 equilibrium ventilation scans. In normal subjects, the U:L lung zone perfusion ratio decreased by 70.7 +/- 12.2% with the change in position. The patient group differed (p less than 0.0001) from normal subjects in that there was only a 19 +/- 17.4% shift of U:L ratio with the postural change. The mean pulmonary arterial pressure in the patient groups was 50 +/- 24.2 mm Hg. The postural change in U:L zone ratio correlated significantly with the mean pulmonary arterial pressure (r = -0.84, p less than 0.01) pulmonary arterial systolic (r = -0.83, p less than 0.01) and diastolic pressures (r = -0.72, p less than 0.05) and with the pulmonary vascular resistance (r = -0.74, p less than 0.02). No correlation was found with other hemodynamic, spirometric or blood gas data. We conclude that the postural shift in U:L ratio warrants further exploration as a noninvasive approach for detecting and quantifying pulmonary hypertension.

Adult↗
PubMed1982

Influence of UV- and capsaicin-induced erythema as well as of acetylsalicylic acid on the urinary excretion of vanilmandelic acid and homovanillic acid in man.

In the present study we investigated whether by means of urinary excretion of vanilmandelic acid (VNA) and homovanillic acid (HVA), resp., the two main metabolites of adrenaline, noradrenaline and dopamine, informations could be obtained on synthesis and release of catecholamines in inflammation. UV- and capsaicin-induced erythema, resp., were used as the inflammatory models. The urinary excretion or both VMA and HVA were found to be decreased after UV irradiation. Administration of acetylsalicylic acid during UV irradiation inhibited the decrease of VMA excretion whereas HVA excretion remained low. The application of capsaicin as a plaster failed to influence the urinary VMA and HVA excretion. Our results could be explained on the basis of the interrelationship between catecholamines and prostaglandins. Other possible mechanisms are discussed.

Adult↗
PubMed1982

Renal excretion of vanillylmandelic acid and homovanillic acid in rats with paw edema or adjuvant arthritis.

1. Urinary excretion of unconjugated vanillylmandelic acid (VMA) and homovanillic acid (HVA) was found to be decreased in adjuvant arthritic rats. The decrease is apparently not due to impaired animal activity, but it could be explained by the reduction of catecholamine biosynthesis and/or release induced by E prostaglandins the biosynthesis of which is increased in the inflammation. It could also be caused by an increased "consumption" of catecholamines during prostaglandin biosynthesis. 2. Both the reduction of biosynthesis or release and an increased "consumption" of catecholamines would mean that inflammation is characterized by deficiency of the anti-inflammatory catecholamines. 3. The investigations failed to demonstrate an adequate decrease of the urinary excretion of VMA and HVA in rats with edemas induced by carrageenin, serotonin, formaline, silver nitrate, kaolin, dextran and baker's yeast, respectively. The experiments should be repeated with other catecholamine metabolites.

Animals↗
PubMed1980

[Problems of statistical evaluation of stereological data from single cells].

A definition of morphometrical parameters of single cell populations is given. Methods for estimating these quantities (confidence estimation included) are described. For the comparison of equivalent parameters of 2 cell populations 2 statistical test procedures replacing the common t-test, are discussed. In addition, a homogeneity test is proposed for comparing the distributions of morphometrical data.

Cell Nucleus↗
PubMed1977

[Therapeutic results using combined antibiotic therapy in chronic carriers].

From 1969 to January 1976 82 chronic carriers underwent a sanitation treatment. This treatment consists in an antibiotic combination treatment with ampicillin and canamycin during 24 to 18 days, in which case possibly simultaneously the cholecystectomy is striven for. In chronic carriers of S. typhi in 37 cases the combined antibiotic-operative treatment led to the permanent success. In chronic carriers of S. paratyphi B 21 of 22 cases were present. In patients with condition after cholecystectomy in every case one failure was present. In purely conservative approach the coefficient of success was 50 and 78%.

Anti-Bacterial Agents↗
PubMed1977

Removal of guanidinosuccinic acid by hemodialysis.

The dialysis clearance of guanidinosuccinic acid (GSA) was measured in vitro and in vivo in patients undergoing maintenance hemodialysis. The in vitro (44 +/- 5 [SEM] ml/min) and in vivo (40 +/- 7 ml/min) clearances were similar to and lower than those of urea and creatinine. Plasma GSA concentrations predialysis (210 +/- 49 microgram/100 ml) were higher then those of controls ( less than 40 microgram/100 ml) and decreased substantially at the end of a single hemodialysis (percent decrease: 53 +/- 5). Marked increase of plasma GSA concentrations 12 h postdialysis were found in only two cases. An attempt was made to derive a single curve predicting plasma GSA decline during dialysis using the data obtained in these patients. The removal data suggest that the space of distribution of GSA approximates the extracellular fluid volume.

Guanidines↗
PubMed1977

Regulating the "size of mesh" in drug screening from statistical point of view demonstrated by a 2-step procedure of in vivo testing of antiviral compounds.

The present paper indicates how to regulate the "size of mesh" in drug screening by sample size and/or by modification of the statistical procedure used. Such a regulation is demonstrated on a 2-step procedure of in vivo testing of antiviral compounds as an example, by changing the rules of decision with the parameter R0. From the computed probabilities of discarding substances with defined effectivities, curves have been drawn which allow to read off immediately sample sizes and R0-values for a desired "size of mesh".

Antiviral Agents↗
PubMed1976

Testing of antiviral compounds against Mengo virus infection of mice. A 2-step procedure of in vivo screening.

A 2-step procedure of screening of antiviral compounds in vivo is presented on the basis of standardized methods of both experimental examination and statistical analysis. The procedure uses the "rate of protection" R as the sole criterion of activity. In the first step, requiring a total of 40 mice, compounds with significant R are detected. Drugs producing R less than 15% are discarded. Compounds eliciting R larger than or equal to 15%, without significance, are examined in a second step, using again 40 mice, to decide whether the protective activity becomes significant employing a greater number of animals. The procedure works with relatively less expense with regard of the number of animals used and the time required. The procedure can be applied to test systems based on lethal infections as well as to test models for which the use of the "rate of protection" is relevant.

Animals↗