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Biomedical subjects

R Lange

Publications and source records attributed to R Lange.

At least 361 records · Page 20Linked to original sources
PubMed1984

The relative importance of alkalinity, temperature, and the washout effect of bicarbonate-buffered, multidose cardioplegic solution.

Recent experimental and clinical studies from our institution have shown that the administration of cold, bicarbonate-buffered, hyperkalemic crystalloid cardioplegic solution resulted in a significant rise in intramyocardial pH. This rise could theoretically be caused by (1) the alkalinity of the solution administered (pH 8.2 at 25 degrees C), (2) the washout of acid metabolites with each administration, and (3) hypothermia per se. To investigate the relative effects of each of these three factors on intramyocardial pH, dogs on cardiopulmonary bypass received crystalloid cardioplegic solution either at 10 degrees C (n = 9) or at 37 degrees C (n = 8) every 30 min during 2 hr of aortic cross-clamping. Myocardial temperature, intramyocardial pH, and CO2 tension (Pmco2) were measured continuously. Needle biopsy specimens were taken every 30 min for biochemical and ultrastructural analysis. Before aortic cross-clamping, intramyocardial pH was 7.07 +/- 0.06 in both groups (+/- SEM). Upon each administration of cardioplegic solution, hearts in the 10 degrees C group cooled to 10 degrees to 15 degrees C and intramyocardial pH increased on the average by 0.31 +/- 0.03 units (p less than .001). In the 37 degrees C group intramyocardial pH was unaffected by cardioplegic solution. At the end of the cross-clamping period, intramyocardial pH had declined to 6.49 +/- 0.13 in the 10 degrees C group and to 5.60 +/- 0.08 in the 37 degrees C group, the fall in pH being significantly greater in the 37 degrees C group than in the 10 degrees C group (p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1983

[Attempted suicide by intake of pholedrine].

It is reported on an attempted suicide of a 21-year old female patient with a lethal dose of 60 to 80 tablets pholedrine longo. A pulmonary oedema could be observed in the patient. This was accompanied by hypotensive crises of blood pressure, which compelled us to use dopamin. Under therapy a stabilization of the behaviour of the patient could be achieved. Pathological liver values were diagnosed. The findings got were discussed and compared with the data of former publications.

Adult↗
PubMed1983

Studies by e.p.r. spectroscopy of carbon monoxide oxidases from Pseudomonas carboxydovorans and Pseudomonas carboxydohydrogena.

E.p.r. spectra were obtained at 8-120 K for carbon monoxide oxidases isolated from the carboxydotrophic bacteria Pseudomonas carboxydovorans and Pseudomonas carboxydohydrogena. Spectra from the two enzymes are extremely similar to one another. Under appropriate conditions each enzyme shows signals from Mo(V) atoms in two different chemical environments, as well as showing signals from two distinct iron-sulphur centres, presumed to be [2Fe-2S] clusters, and weak FADH X free-radical signals. Parameters of most of the signals were measured, and they show considerable similarities to those of the corresponding signals from xanthine oxidase and related enzymes. Though the signals from carbon monoxide oxidases appear and disappear under reducing and oxidizing conditions, we have so far failed to demonstrate the kinetic competence of any of them. It seems likely that this was due to the presence in the enzyme preparation examined of high amounts of desulpho carbon monoxide oxidase together with another non-functional form of the enzyme giving a stable 'Resting' Mo(V) e.p.r. signal.

Aldehyde Oxidoreductases↗
PubMed1983

Evaluation of antiarrhythmic activity of prostaglandin F2 alpha in man.

Since prostaglandin (PG) F2 alpha had been shown to act anti-arrhythmically in various animal models and also in preliminary investigations in man, further evaluation of this effect was made in 30 patients with cardiac extrasystoles and in 2 patients with tachycardias. PGF2 alpha was infused intravenously at individually adapted consecutive rates from 5 to 100 micrograms/min each for at least 5 min. In the incidence of extrasystoles a mean maximum decrease of 41% (P less than 0.001) was obtained. One patient showed repeated short interruptions of a ventricular tachycardia. A dose-dependent significant rise in blood pressure and no significant influences on heart rate, PQ interval and QRS interval of the ECG were found. It is concluded that PGF2 alpha has probably no practical importance for the therapy of cardiac arrhythmias.

Adult↗
PubMed1983

Gold-195m for serial first pass radionuclide angiocardiography during upright exercise in patients with coronary artery disease.

Sequential first pass radionuclide angiocardiography can be performed in rapid succession using gold-195m because of its low radiation dose and short half-life (30.5 seconds). In 25 patients with known or suspected coronary artery disease, first pass studies with gold-195m were obtained using a computerized multicrystal gamma camera at rest (n = 29), at the end of each 3 minute stage of exercise (n = 25) and immediately after exercise (n = 23). In 13 patients, assessment of left ventricular function during exercise with gold-195m was combined with thallium-201 stress scintigraphy. Left ventricular ejection fraction at rest assessed with technetium-99m and gold-195m correlated well (r = 0.93). In addition, repeat left ventricular ejection fractions at rest with gold-195m correlated closely (r = 0.96). Comparing peak exercise left ventricular ejection fraction with ejection fraction at rest, abnormal left ventricular reserve was found in 20 of 25 patients. Various abnormal patterns of left ventricular ejection fraction response were noted, showing the diagnostic potential of serial exercise angiocardiography. Thallium-201 myocardial images, obtained on a single crystal gamma camera after multiple gold-195m injections, were all of good diagnostic quality and were abnormal in 10 of 13 patients. Thus, multiple high count rate first pass studies can be obtained with gold-195m during and after exercise, allowing serial study of physiologic changes in left ventricular function during exercise. Thallium-201 myocardial imaging can be performed using the same exercise test, providing direct comparison of myocardial function and perfusion.

Adult↗
PubMed1983

Kinetics of primary interaction of D-amino acid oxidase with its substrate.

The formation of an initial enzyme-substrate complex of D-amino acid oxidase (D-amino acid: O2 oxidoreductase (deaminating), EC 1.4.3.3) and its substrate, D-alpha-aminobutyric acid, was studied kinetically at lower temperature and pH than their optima. The time course of the absorbance change at 516 nm in an anaerobic reaction was not exponential, but biphasic. The ratio of the rapidly reacting component to the slowly reacting one was decreased upon lowering of the temperature. The reaction rate of the rapidly reacting component depended on substrate concentration and gave a linear Arrhenius plot in the temperature range from -10 to +15 degrees C. The reaction rate of the slowly reacting component also depended on both substrate concentration and temperature. The rapidly reacting and slowly reacting components could be assigned to the substrate binding of the dimer and monomer, respectively, of this enzyme.

Aminobutyrates↗
PubMed1983

Time course of ischemic alterations during normothermic and hypothermic arrest and its reflection by on-line monitoring of tissue pH.

Currently there are no techniques available for the intraoperative on-line assessment of the adequacy of myocardial preservation during cardiac operation. The efficacy of a new intramyocardial pH electrode in quantitating myocardial ischemic damage and monitoring myocardial preservation was investigated by correlating changes in intramyocardial pH with the time course of metabolic, histologic, and ultrastructural alterations during global ischemia. Seventeen open-chest dogs were placed on cardiopulmonary bypass and the aorta was cross-clamped for 2 hours. In Group I (n = 8), aortic cross-clamping was performed under normothermia. Group II (n = 9) received 4 degrees C potassium cardioplegia immediately after cross-clamping and consecutively every 30 minutes thereafter. Intramyocardial carbon dioxide tension (Pco2) and intramyocardial pH were measured continuously. Serial transmural biopsies were obtained before and at 5, 15, 30, 60, 90, and 120 minutes after cross-clamping for biochemical and structural analysis. During the period of cross-clamping, mean myocardial temperature was 33 degrees C in Group I and 19 degrees C in Group II. Intramyocardial pH at the end of 2 hours of anoxic arrest reached 5.39 +/- 0.08 in Group I and 6.49 +/- 0.13 in Group II (both values p less than 0.01 compared to prebypass values). Intramyocardial Pco2 rose from 41 +/- 4 to 234 +/- 13 mm Hg in Group I (p less than 0.001) and did not change in Group II. Tissue content of adenosine triphosphate (ATP) decreased by 51% in Group I and by 14% in Group II (p less than 0.01 compared to prebypass value). Tissue creatine phosphate was depleted in Group I and decreased by 48% in Group II. The degree of ischemic damage assessed by a mean ischemic score was 2.15 +/- 0.06 in Group I and 0.75 +/- 0.19 in Group II (p less than 0.001). Irreversible structural damage assessed by electron microscopy occurred in Group I 60 to 90 minutes after cross-clamping and was associated with an intramyocardial pH below 6.2. No such damage was observed in Group II. Therefore, intramyocardial pH is shown to be a reliable indicator of the severity of ischemic damage during anoxic arrest under normothermic conditions and of the adequacy of preservation under hypothermic conditions. Measurement of intramyocardial pH may provide a potentially useful tool for the intraoperative on-line monitoring of the adequacy of myocardial preservation in patients undergoing cardiac operation.

Adenosine Triphosphate↗
PubMed1983

Studies of experimental coronary artery reperfusion. Effects on infarct size, myocardial function, biochemistry, ultrastructure and microvascular damage.

The present report is a review of recent experimental studies in a canine model of acute coronary occlusion. The questions addressed were: (1) Does coronary reperfusion reduce myocardial infarct size? (2) What is the relationship between microvascular damage and hemorrhage and the development of myocardial necrosis? (3) What are the biochemical, functional and ultrastructural characteristics of reperfused tissue salvaged from necrosis? Coronary occlusion followed by reperfusion in the dog resulted in significant subepicardial salvage of myocardium if reperfusion was instituted before 6 hours of ischemia. Because ultrastructural evidence of microvascular damage was found only after irreversible damage to myocytes, and because gross hemorrhage after coronary reperfusion was confined to zones of myocardium that were already necrotic, it does not appear that hemorrhage should serve as a deterrent to reperfusing reversibly injured myocytes. Severely ischemic myocardium that had been salvaged by coronary reperfusion required several days before it returned to normal from biochemical, functional and ultrastructural standpoints.

Adenosine Triphosphate↗
PubMed1982

[The performance of ECG telemetry in the analysis of rhythm disorders].

630 outpatients and inpatients under rest as well as under conditions of physical loads and psychic stress were examined with the help of a radiobiotelemetry device of own construction, which corresponds to a combination of traditional radiotelemetry and tape storage. In 81.4% of the patients with hitherto unclarified disturbances of the cardiac rhythm telemetry obtained their qualitative clarification. In 50% of all cases with classical angina pectoris symptomatology the ischaemic heart disease was verified by determination of the usual criterias of ECG at the telemetry stripe. Of these 50% only 7 patients had no arrhythmia. In 57.5% of all examined patients with pacemakers of permanent frequency we could prove a considerable parasystoly in load by telemetry. 9 patients with R-demand-pacemakers became evident by triggering defects in load. During the psychoanalytic examination we registered extrasystoles in 25%, apart from this once developed a pancardiac asystolism. The radiobiotelemetry is a valuable completion of the well-known methods of load.

Arrhythmias, Cardiac↗