Search PubMed⌕ Search

Biomedical subjects

M Friedrich

Publications and source records attributed to M Friedrich.

At least 217 records · Page 12Linked to original sources
PubMed1990

Effects of anoxia on K and Ca currents in isolated guinea pig cardiocytes.

Whole cell currents were measured in isolated cardiocytes of guinea pig under anoxic conditions (pO2 less than 0.5 torr). After 2 to 32 (mean 11.2) minutes of anoxia, time independent outward currents developed gradually which had a linear current-voltage relation between -100 and +20 mV and reversed at the resting potential of the cells (-82 to -90 mV). After 20 to 170 (mean 38) seconds, the amplitude of these outward currents saturated (3.6 +/- 0.5 nA at +10 mV, n = 23). Reoxygenation within one minute after the appearance of the first extra outward currents led in most cells (greater than 90%) to their complete disappearance in 2 to 4 (mean 2.87, n = 15) seconds. Ca currents were not affected at the time when the first extra outward currents occurred. It is concluded that (i) the anoxia-induced outward current is carried by K+ ions probably through KATP channels which open at intracellular ATP concentrations below 1 mmol/l (Noma and Shibasaki 1985) and (ii) this degree of ATP depletion does not affect normal Ca channel function.

Animals↗
PubMed1990

Endosonographic appearance of the esophagus in achalasia.

Primary motility disorders of the esophagus require the exclusion of intramural tumors. The procedures currently used for the differential diagnosis of achalasia such as endoscopy with biopsy, esophageal and gastric radiography, abdomino-thoracic computed tomography and intraluminal esophageal manometry, are unsatisfactory when a tumor growing intramurally is suspected. A more recent method of studying the integrity of the gastrointestinal wall and its surrounding tissue is endoscopic ultrasonography. In 16 patients suspected of having achalasia, endosonography was performed in addition to the above-mentioned conventional examinations. Fifteen of them showed a normal ultrasonic structure of the wall of the gastro-esophageal junction, with no sign of hypertrophy of the smooth muscle layer. In the remaining case endoscopic ultrasonography was able to detect an intramural tumor, as evidenced by the inhomogeneous ultrasonic structure of the esophageal wall. Computed tomography and all the other conventional diagnostic procedures used failed to demonstrate this tumor. In conclusion, the findings presented strongly suggest that endosonography can contribute to the differential diagnosis of achalasia and intramural tumors.

Adult↗
PubMed1989

Effects of carvedilol on left ventricular function and arrhythmias during repeated short-time myocardial ischemia in experimental pigs.

The effects of carvedilol, a new vasodilating beta-blocking drug, were studied in experimental pigs during short-term acute myocardial ischemia. In 21 anesthetized pigs 0.01, 0.03, and 0.1 mg/kg b.w. carvedilol was studied during repeated 2-min distal LAD-occlusions and a 60-min-period of ischemia. Left ventricular volume was continuously measured by the impedance catheter method. Intravenous administration of 0.01 mg/kg carvedilol resulted in a significant decrease of heart rate (-13%), dp/dtmax (-32%), and ejection fraction (-9%), slight changes of systolic pressure (-3%), and an increase of vascular resistance (+24%), indicating a beta-blocker effect without vasodilation-while the first vasodilatory effect was found at a dose of 0.1 mg/kg. During ischemia carvedilol had no influence on the time-course or the extent of systolic bulging of the ischemic myocardium, but the ischemia-induced decrease of left ventricular ejection fraction was diminished. Both during short-term ischemia, as well as during the 60-min-ischemia-period carvedilol significantly reduced ventricular premature beats. During the 60-min-ischemia-period activation delay measured from local DC-electrograms of the ischemic myocardium, as well as the occurrence of activation block were not altered by carvedilol, as was the incidence of ventricular fibrillation (69%). We conclude that at low dosages the beta-blocking effect of carvedilol exceeds the vasodilating properties. This may also hold true in patients with cardiac failure; they are more sensitive to beta-blocking drugs. During ischemia carvedilol slightly reduces the ischemia-dependent decrease of global ventricular function and it has an antiarrhythmic effect. Therefore, it may be protective in patients with acute myocardial infarction.

Adrenergic beta-Antagonists↗
PubMed1989

[Amiodarone-induced segmental lung infiltration. Radiologic and computed tomographic aspects].

Due to pulmonary toxicity, segmental lung consolidation or diffuse interstitial pulmonary infiltrations can occur during long-term treatment of ventricular tachycardia with amiodarone (Cordarex). These infiltrations can be confused with other infectious pneumonic consolidations, dystelectasia or tumorous lung disease, and may be erroneously treated as such. Apart from the clinical symptoms (dyspnea, non-productive cough, low-grade fever), the earliest radiographic signs are segmental infiltrates or diffuse interstitial lung opacifications. Pathological pulmonary function tests can only be observed in the early stages of the diffuse alveolar-fibrosing form of the disease. In this case study of amiodarone-induced segmental pulmonary infiltration, the radiological and computer-tomographic aspects are discussed, along with other complementary diagnostic procedures such as gallium scintigraphy and bronchoscopic biopsy.

Amiodarone↗
PubMed1989

[The growth of rats in renal compensatory adaptation in feeding with a supplemented diet of hydroxy-analogs of essential amino acids].

Rats were fed protein-restricted after unilateral nephrectomy (6.7% casein). Comparatively other animals were fed with experimental diets, at which 20% of the casein have been replaced by Ketosteril or a mixture of hydroxy acid. The constituents of this mixture are in accordance with the molar relation of all Ketosteril components. However, sodium solts of hydroxy acids of leucine, isoleucine and valin replace the corresponding keto acids of Ketosteril. The other components of the mixture consist of free amino acids. The efficiency of protein utilisation was judged by the relation of increased body weight and nitrogen intake. The efficiency of protein utilisation of both supplemented diets is 2.5 times higher compared with the casein diet.

Amino Acids, Essential↗
PubMed1988

[Endosonographic findings of benign and malignant lesions in the stomach wall. A prospective comparison with conventional imaging study procedures].

The results of endoscopic ultrasonography in the diagnosis and differentiation of benign and malignant lesions of the stomach was prospectively compared with those obtained by upper endoscopy with biopsy, double-contrast radiography and computed tomography in 15 patients with benign and 26 with malignant gastric lesions. The validity of the methods was established by comparing the results obtained with the long-term course observed clinically in conjunction with an endoscopic-histological follow-up or with the findings on histopathological examination of the operative specimen. Precise diagnosis of the lesion was made by endoscopic ultrasonography in about 90% of cases, a result better than that obtained with radiography or computed tomography. Furthermore, endoscopic ultrasonography had good sensitivity for demonstrating perigastric lymph node enlargement; in this respect it was better than computed tomography, but was not able to distinguish whether the enlargement was benign or malignant: this will only become possible with technical improvement of the instruments.

Adenocarcinoma↗
PubMed1988

[Bioavailability of minerals. 1. Determination methods].

Minerals have a important role in metabolism. Only a little is known on the recommended intake for maintenance of body function. Supplying depends on the bioavailability. Methods for experimental determination are described and limits and possibilities are discussed.

Biological Availability↗