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Biomedical subjects

F Ebner

Publications and source records attributed to F Ebner.

122 records · Page 7Linked to original sources
PubMed1981

[Tumor diagnostic by ERPC and its correlation to pathology (author's transl)].

In relation to 170 pancreatic and bile duct neoplasms confirmed by histology, the radiological signs were correlated to anatomical findings. The roentgenograms were analysed with regard to diagnostic accuracy, size of tumor and operability. 13 319 autopsies of the same period were screened in order to ascertain false positive and as well false negative findings in ERPC. Pancreatic tumors with a diameter over 3 cm were correctly found by ERPC in 98,4%, tumors below 3 cm in diameter in 75%. The over-all diagnostic accuracy for malignant tumors was 90,0%. There were no pathological findings in ERPC in two cases of pancreatic cancer with diameter below 3 cm. 10,5% of all pancreatic neoplasms were operable. Tumors of extrahepatic bile ducts all were discovered by ERPC but all of them were already inoperable.

Aged↗
PubMed1980

[Catecholamine-antagonistic effects of propranolol and the mechanical function of ventricular myocardium].

The catecholamine-propranolol antagonism was studied on guinea-pig papillary muscles. 1. A competition between propranolol and catecholamine, the latter subject to saturable elimination from the extracellular space, for a homogeneous populations of beta-adrenoceptors of the cellular surface does not suffice to explain the influence on the inotropic effects. 2. The antagonism was differentiated into a "surmountable" and an "unsurmountable" component by means of the stereospecific influence of propranolol on maximal catecholamine effects in regard to velocity of contraction and acceleration of relaxation. The "unsurmountable" component was explained by a competition for intracellular beta-adrenoceptors, in addition to the competition at the beta-adrenoceptors of the cellular surface ("surmountable" component).

Animals↗
PubMed1979

The influence of (+)-propranolol on the inotropic effect of dihydro-ouabain in relation to stimulation frequency.

1. The influence of (+)-propranolol, 10(-6) to 4 x 10(-5) mol/l, upon the positive inotropic effect of dihydro-ouabain was studied on guinea-pig papillary muscle. At 1 Hz, negative inotropically effective concentrations of (+)-propranolol decreased the inotropic effectiveness of the glycoside. 2. For equivalent diminution of the basal force of contraction, either by reduction of stimulation frequency or by increasing concentrations of (+)-propranolol, a similar decrease in the inotropic effectiveness of dihydro-ouabain was observed. In contract, reduction of [Ca2+]o had almost no effect on the effectiveness of the glycoside. 3. The inhibitory effect of (+)-propranolol on the inotropic effectiveness of dihydro-ouabain declined with reduction of stimulation frequency. At any stimulation frequency tested, the inhibitory effect of (+)-propranolol was proportional to the effect of a reduction of that particular frequency to the rested-state condition in the absence of (+)-propranolol. 4. The results are consistent with the hypothesis that the inhibition of the excitation-coupled sodium influx by (+)-propranolol is the cause of its inhibiting effect on the effectiveness of dihydro-ouabain.

Animals↗
PubMed1978

The role of uptake of noradrenaline of its positive inotropic effect in relation to muscle geometry. Statistical evaluation.

1. The influence of saturable drug uptake on the drug concentration near the receptor sites was shown theoretically to depend on the geometry of the preparation; increases in the volume/surface ratio (V/S) of the preparation decrease the sensitivity of the preparation to an agonist inactivated in the tissue. 2. The positive inotropic effect of (-)-noradrenaline was found to depend on the ratio V/S of the preparation; papillary muscles with larger V/S were less sensitive to the drug and showed steeper noradrenaline concentration-effect curves. 3. An algorithm for the statistical estimation of the parameters of the saturable uptake process was derived. It was applied to the positive inotropic noradrenaline effect in relation to muscle geometry. As an analysis of variance showed, the model explained a significant proportion of the shift of (-)-noradrenaline concentration-effect curves associated with variation in size of the preparation.

Animals↗
PubMed1977

Anti-arrhythmic properties of acebutolol (Bay c 7705), a new cardioselective beta-adrenergic blocking agent: a preliminary report.

A study was carried out in 20 ambulatory patients with various heart diseases and different forms of cardiac arrhythmias to evaluate the anti-arrhythmic effect of acebutolol when given orally(400 mg/day). Long-term(4 hour) ECGs were monitored before and after 3 days of treatment. The results showed that after acebutolol treatment 60% of all the arrhythmias were prevented or abolised, 16% were improved, and only 24% persisted unchanged.

Acebutolol↗
PubMed1973

Convergent projection of three separate thalamic nuclei on to a single cortical area.

Three distinct sensory-motor nuclei in the thalamus project to parietal cortex in the Virginia opossum; the ventral posterior nucleus receives inputs from somatic sensory structures and projects to layers IV and III, the ventral anterolateral nucleus receives inputs from motor structures and projects to layers IV and III and inner I, and the central intralaminar nucleus receives inputs from sensory, motor, and other structures and projects to layers VI through outer I. The physiologically defined amalgamation of somatic sensory and motor cortex is correlated, therefore, with the extent of cortex that receives convergent somatic sensory and motor input from the thalamus.

Animals↗
PubMedDate not supplied

Temperature monitoring of interstitial thermal tissue coagulation using MR phase images.

The temperature-dependent water proton frequency shift was investigated for temperature monitoring of interstitial thermal coagulation. A procedure for on-line temperature calculation was developed, and errors due to temperature-dependent susceptibility were investigated by finite element analysis and reference measurements. The temperature coefficient of magnetic susceptibility and proton chemical shift were determined for brain tissue and other substances. With the proposed procedure, the location of isotherms could be well visualized during laser-induced interstitial coagulation in vitro and in vivo. Systematic errors caused by magnetic susceptibility changes with temperature depend strongly on the characteristics of the heat source and can exceed susceptibility effects caused by physiologic tissue changes. For the laser applicators discussed here, however, a first order compensation for this effect was found to be satisfactory, because it reduces the absolute error to the range of +/- 1 degrees C. The proposed method represents a very promising approach for monitoring of the interstitial thermal coagulation.

Adipose Tissue↗
PubMedDate not supplied

MR-imaging with Gd-DTPA in carcinomas of tongue, oro- and hypopharynx.

High-field MRI was performed in a series of 24 patients with squamous cell carcinomas of the tongue, oro- and hypopharynx. The value of contrast enhanced T1-weighted images in tumor staging was established prospectively. Non-contrast T1-weighted images did not provide sufficient tumor-delineation. Marked contrast enhancement produced by Gd-DTPA was observed in all carcinomas and in normal pharyngeal mucosa. In tumors of the tongue and upper pharynx clinical examination and ultrasound were equally sensitive as post-contrast MRI; in tumors of the lower pharynx the true tumor extension could be better assessed by contrast-enhanced MRI.

Adult↗
PubMedDate not supplied

Multiple sclerosis in children: value of serial MR studies to monitor patients.

A series of six children with clinical (4) and laboratory (2) evidence of multiple sclerosis is described. The mean age at onset was 12 years and the female-male ratio was 5:1. All patients had white matter abnormalities on initial MR scans. On follow-up MR studies, performed every 3 to 5 months, all children exhibited changing patterns of CNS signal abnormalities. In three cases, clinically silent brain lesions were detected. In four patients with an acute clinical attack, large lesions were present, demonstrating a lamellar structure on T1- and T2-weighted images. The lesions were seen best on long TR/short TE spin-echo sequences. Combined sagittal and axial series with EKG gating and flow-compensation technique were best for MR follow-up studies. Our results show that MR is useful for monitoring patients with multiple sclerosis.

Adolescent↗
PubMedDate not supplied

MR findings in methotrexate-induced CNS abnormalities.

MR of the brain was performed in eight patients (mean age, 14.9 years) with osteogenic sarcoma during or after IV treatment with high-dose methotrexate. MR detected brain abnormalities in four patients, three of whom had concomitant neurologic dysfunction. Pathologic findings demonstrated on MR were (1) chronic brain edema, demonstrable over a period of 3-14 months (proved by autopsy in one patient); (2) multifocal white matter necrosis; and (3) deep brain atrophy. MR appears to be valuable in the detection of abnormalities induced by treatment with high-dose methotrexate.

Adolescent↗