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Biomedical subjects

B Grote

Publications and source records attributed to B Grote.

At least 19 recordsLinked to original sources
PubMed2000

Dominance of radiative coupling over disorder in resonance Rayleigh scattering in semiconductor multiple quantum-well structures.

Resonance Rayleigh scattering by periodic semiconductor multiple quantum-well structures is studied experimentally and theoretically. Polaritonic effects are found to dominate disorder in the secondary emission dynamics. The coexistence of several radiant polaritonic modes with different radiative decay times leads to polarization beating between modes, strongly influences the rise times, and determines the fast decay times of the resonance Rayleigh scattered signals.

Journal Article↗
PubMed1990

[Preoperative treatment with beta-receptor blockers and isoflurane anesthesia. Hemodynamic interactions in patients with coronary disease].

Although many patients undergoing general anesthesia and surgery are pretreated with beta-adrenoceptor blocking drugs, hemodynamic interactions of beta-blockers and volatile anesthetics have so far only been studied in animals. We therefore designed a clinical study to evaluate the relationship between the extent of preoperative beta-adrenoceptor blockade and the hemodynamic effects of isoflurane anesthesia. Sixty-one patients with coronary artery disease (CAD) and normal global left ventricular function scheduled for elective myocardial revascularization were studied immediately prior to surgery. One group of patients (n = 39) had been treated with beta-adrenoceptor blocking agents for at least 3 weeks up to and including the day of surgery. The degree of clinical beta-adrenoceptor blockade was quantified using the isoproterenol sensitivity test. The dose of isoproterenol required to increase heart rate by 25 beats/min was defined as the chronotropic dose 25 (CD25), representing the degree of beta-adrenoceptor blockade. Hemodynamic data were collected before and during isoflurane anesthesia (0.5%-0.6% end-tidal) plus 50% nitrous oxide. Twenty-two patients without preoperative beta-blocker therapy served as a control group. Preanesthetic values of cardiac index (CI), heart rate (HR) and mean arterial pressure (MAP) were lower in patients pretreated with beta-blocking drugs, but statistically these differences were not significant when compared to data obtained in unblocked patients. Isoflurane anesthesia caused significant reductions of CI and arterial blood pressure. However, there were no significant differences in the absolute values or the percentage changes compared to baseline data obtained in awake patients between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1990

[A successful lytic treatment of a perioperative pulmonary embolism necessitating resuscitation using recombinant tissue-type plasminogen activator].

We report a patient with massive perioperative pulmonary embolism (stage IV) and cardiac arrest who was successfully treated with recombinant tissue plasminogen activator (rt-PA). Thrombolytic therapy was started with 25 mg rt-Pa over 15 min followed by another 25 mg over 45 min. During the next 5 h 50 mg were infused, and thereafter an additional 50 mg over 24 h. No major alterations in the plasmatic coagulation profile were noted. With the exception of moderate blood loss from one puncture site, no further bleeding complications occurred. The relevance of this new thrombolytic agent in the perioperative management of acute, life-threatening pulmonary embolism is discussed.

Humans↗
PubMed1982

Plasma concentration and E.E.G. after various regimens of etomidate.

Etomidate was injected i.v. within 10 or 60 s at various doses. After etomidate 0.3 mg kg-1 the plasma concentration was 1.6 micrograms ml-1 at 1 min after the end of injection. For about 7 min a good hypnotic effect (stages C0-D2) was observed on the e.e.g. recording. For surgical procedures, however, a combination with analgesic drugs appeared to be necessary. When the dose of etomidate was increased (0.1-0.4 mg kg-1) a linear increase in plasma concentration and slow e.e.g. activity was observed concomitantly. Anaesthesia could be prolonged with additional injections or with continuous infusion. Each additional injection produced a steep increase in concentration of short duration with marked deepening of hypnosis. The infusion induced only a moderate increase in plasma concentration, whereas the depth of sleep during the period of infusion remained nearly the same. E.e.g. changes induced by etomidate are similar to those after barbiturates and other i.v. anaesthetics.

Adult↗
PubMed1981

Sleep-wake pattern in preterm infants under two different care schedules during four-day polygraphic recording.

The sleep-wake pattern of healthy preterm infants under two different schedules of routine procedures was studied by 4-day polygraphic-recording. Group-I experienced the usual routine care conditions, Group-II remained less disturbed by means of time-coordination of the procedures. Group-II-infants were less awake, showed a higher percentage of active sleep and the undisturbed phases of active and quiet sleep were longer than in Group-I-infants. Routine procedures left Group-II-infants more often in an unchanged state than Group-I-infants, the latter exhibiting an arousal reaction more frequently. The unknown effect of sleep disturbances in preterm-infants demands a reduction and coordination of routine procedures as far as possible.

Arousal↗
PubMed1981

[The antagonistic effect of physostigmine on sedation by lormetazepam (author's transl)].

The purpose of this study was to determine the arousal effect of physostigmine after lormetazepam sedation on the human EEG. 12 male volunteers received 2 mg/kg bm lormetazepam and 30 minutes later physostigmine 2 mg preceded by atropine 1 mg. Generally an arousal effect of physostigmine could be clinically observed and more objectively demonstrated by reduced sleep stages in the vigilosomnogram (p less than 0.05). 2 volunteers did not fall asleep. 9 volunteers were awake 5-12 minutes after termination of physostigmine injection. 1 volunteer did not show any effect. Resedation and parasympathetic side effects did not occur. In earlier studies deep sleep stages after lormetazepam 1 or 2 mg/70 kg bm lasted 70 to 120 minutes. Physostigmine is recommended to counteract undesirable benzodiazepine induced sedation.

Anti-Anxiety Agents↗
PubMed1981

[Intramuscular application of midazolam. Its effect upon CNS and respiration (author's transl)].

8-Chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a] [1,4]benzodiazepine (midazolam, Ro 21-3981, Dormicum) is a benzodiazepine with a pronounced sleep-inducing effect. Deep-sleep stages and respiratory depressions were observed after 5 mg i.v. Whether and in what dosage midazolam can be safely, i.e., without continuous monitoring administered i.m. must be shown by the analysis of larger study populations. After i.m. injection, there is rapid onset of action leading to sleep stages which are comparable only with those hitherto observed after i.v. injection.

Anti-Anxiety Agents↗
PubMed1978

[Therapy of cardiac arrest: cardiopulmonary resuscitation (author's transl)].

Reports of successful attempts at resuscitation have been published for more than 200 years, but systematic analysis of an optimal technique has been undertaken for only the last 20 years. As a result of these experiments and of the many years of experience of resuscitation teams, extensive recommendations were formulated by a conference on cardiopulmonary resuscitation of the "American Heart Association" in May 1973. The superiority of mouth-to-mouth resuscitation in comparison to older methods and the importance of the triple-airway-maneuvre for the maintenance of a patent airway were pointed out. Despite the fact, that an exact numerical relationship of cardiac massage to artificial ventilation is not particularly important, an optimal procedure was established. However, the worldwide spread of cardiopulmonary resuscitation should not lead to this procedure being performed just somehow, since correct execution, if possible without interruptions, is essential for the effectiveness of the remaining circulation and the response to medications and defibrillation. The prognosis varies widely depending on the group of patients being examined. In 1976 34 resuscitations were performed on adult patients of the Cardiothoracic Intensive Care Unit of the German Heart Centre in Munich (5.5% of patients admitted). Seven patients survived primarily. Of these, four patients died within the subsequent twentyfour hours. One patient survived with permanent brain damage, two could eventually be discharged from the hospital without complications.

Coronary Care Units↗