Radiologische Leistungen im Nacht- und Bereitschaftsdienst

Zusammenfassung In der Zeit vom 01. Juli 1990 bis zum 30. Juni 1994 wurden 65 113 Untersuchungen au?erhalb der Regeldienstzeit durchgeführt. Die vorliegende Analyse schlüsselt die Leistungen auf nach Alter und Geschlecht im Vergleich zum Gesamtkollektiv dieser Vierjahresperiode, nach dem Zeitpunkt der Untersuchung, nach den untersuchten Organen und nach der eingesetzten Technik. Ca. ¹/₃ der Leistungen fallen in den Zeitraum zwischen 16.00 und 20.00 Uhr und k?nnten durch einen versetzten Tagdienst aufgefangen werden. Ein weiteres Drittel entf?llt auf den Zeitraum zwischen 20.00 und 8.00 Uhr am Folgetag. Der Rest entf?llt auf Feiertage und Wochenenden. Die h?ufigste Anforderung betrifft Thoraxaufnahmen auf den Intensivstationen. Etwa die H?lfte dieser Untersuchungen werden au?erhalb der Dienstzeit angefertigt; 17,2 % der Untersuchungen im Nacht- und Bereitschaftsdienst betreffen Computer- und Magnetresonanztomographie. Das am 01. 01. 93 in Kraft getretene Gesundheitsstrukturgesetz führte zu keinen nennenswerten Verschiebungen hinsichtlich Art, Umfang und H?ufigkeit der Untersuchungen im Nacht- und Bereitschaftsdienst. Eingegangen am 17. Juni 1996 Nach überarbeitung angenommen am 24. Juli 1996     

Absence of beta-adrenergic receptor involvement in cerebrovascular dilation by halothane in monkeys

We determined, in monkeys, whether halothane-induced cerebrovascular dilation is mediated by beta-adrenergic receptors and whether cerebrovascular tone progressively returns to baseline values during prolonged halothane anesthesia. Total cerebral blood flow (CBF), cerebral perfusion pressure, plasma halothane concentration, and arterial blood gas tensions and pH were measured in 14 rhesus monkeys mechanically ventilated with 0.5% (inspired) halothane, 33% O2 and balance N2O. Halothane was increased to 2.0% and the measurements repeated 30 and 60 min later. Then either 0.9% NaCl (controls n = 6) or propranolol (n = 8), 1.0 mg/kg was infused intravenously over 10 min, and the measurements repeated at 70, 90, 120, and 150 min. After 30 min at 2.0% halothane, CBF increased in the controls by 50% (P less than 0.05) from 92 +/- 8 (mean +/- SD) to 137 +/- 39 ml X 100 g-1 X min-1 and in the propranolol group by 30% (P less than 0.05) from 106 +/- 33 to 137 +/- 28 ml X 100 g-1 X min-1. After 2.5 hr of 2.0% halothane anesthesia, CBF remained elevated above baseline levels, but by only 28 and 23% in the control and propranolol groups, respectively. Cerebrovascular resistance was identical in both groups (0.55 +/- 0.33 vs 0.53 +/- 0.13 mm Hg X ml-1 X 100 g 1 X min 1). The results show that there is only a 10-20% return of CBF toward baseline levels after up to 2.5 hr of 2% halothane anesthesia. The results also indicate that halothane-induced cerebrovascular dilation is not mediated by beta-adrenergic receptors.     

Phagocyte function and cytokine production in community acquired pneumonia.

BACKGROUND--It is possible that many deaths from pneumonia may involve the generation of inflammatory mediators and tissue damage by activated phagocytes. To test this hypothesis phagocyte function, plasma levels of interleukin 6 (IL-6), tumour necrosis factor alpha (TNF alpha), and soluble interleukin 2 receptor (IL-2R), disease severity, and outcome have been examined in 46 patients with community acquired pneumonia. METHODS--Polymorphonuclear leucocyte (PMNL) and monocyte function were measured daily by chemiluminescence in these patients during the first week of admission, and cytokine levels were subsequently determined by ELISA. A series of 61 healthy individuals were used as a control group for the chemiluminescence results. RESULTS--There was evidence of phagocyte, particularly PMNL, activation on admission in 76% of the patients. Most patients (86%) also had raised IL-2R levels on admission. IL-6 and unbound TNF alpha were present in 23% and 41% of patients at varying times during the course of the disease. There was little correlation between measurements of cytokine or phagocyte levels and outcome or indicators of disease severity, although this may be because of the small number of patients included in this preliminary study. CONCLUSIONS--These results are consistent with the hypothesis that activated phagocyte function and raised levels of circulating cytokines may contribute to the pathogenesis of community acquired pneumonia. There are striking similarities in this respect between pneumonia, adult respiratory distress syndrome, and sepsis.     

Stimulus effects of ibogaine in rats trained with yohimbine, DOM, or LSD.

The stimulus effects of ibogaine were compared with those of yohimbine, an alpha 2-adrenoceptor antagonist, 2,5-dimethoxy-4-methylamphetamine (DOM), a 5-hydroxytryptamine2 (5-HT2) agonist, and lysergic acid diethylamide (LSD), a nonspecific 5-HT agonist. Rats were trained with either yohimbine (6 mg/kg), DOM (0.6 mg/kg), or LSD (0.1 mg/kg) vs. no treatment in a two-lever discrimination task. Tests of generalization were then conducted with ibogaine. In yohimbine-trained animals, 39.7% of responses following ibogaine (15 mg/kg) were on the drug-appropriate lever, but this response level was not significantly different from no treatment-appropriate responding. A response distribution that was significantly different from responding under both drug and no treatment training conditions was observed in DOM-trained rats after administration of 15 mg/kg ibogaine. Pizotyline (BC-105) blocked all DOM-appropriate responding produced by ibogaine. In LSD-trained animals, 20 mg/kg ibogaine mimicked LSD. Pizotyline blocked LSD-appropriate responding produced by ibogaine in five of six animals. The present data suggest the involvement of 5-HT2 receptor activity, and the possibility of a 5-HT1A contribution, in the stimulus properties of ibogaine.     

Tumour induction as a consequence of immunosuppression after renal transplantation

Immunosuppressed recipients of organ transplants have a higher incidence of carcinoma than the general population. A retrospective analysis was made at the Department of Urology of Bonn University, investigating 236 renal allograft recipients as to the incidence of neoplasms before and after transplantation. Eleven patients developed malignant tumours after transplantation. In 4 out of these 11 patients, case history showed pre-existing malignancies. Two of the 4 patients developed a second tumour, while the other two had tumour progression (latency period 21–77 months). Three of the 4 patients died of their tumours 21, 42 and 77 months after transplantation, whereas one female patient is still alive and free of neoplasms 32 months after transplantation. In 7 out of these 11 patientsde novo tumours were diagnosed (latency period 3–88 months). All of them are still alive (NED between 15 and 85 months), six of them with good transplant function. There was no difference to be seen in the incidence of malignancies between kidneys supplied by Eurotransplant (n=40) and ABO compatible kidneys from our own donors (n=196). The higher incidence rate of neoplasms in transplant recipients requires high standards in preventive measures. Any suspicious change that may occur in the course of a thorough follow-up of transplant recipients must be removed and examined histologically. Patients with previous malignant diseases must be payed special attention, since they frequently tend to develop another malignant tumour and progression of existing tumours, respectively. As far as immunosuppression is concerned, therapeutic guidelines for the treatment of transplant recipients do not differ from those set up for patients on haemodialysis. Since immunosuppression with increased rates of tumour incidence can also be observed in dialysis patients, the mere fact of increased incidence of neoplasms cannot be taken as an argument against transplantation. With a more or less equal risk of tumour incidence the crucial factor should be the higher quality of life for transplant recipients.     

The effect of glucocorticosteroids on the neonatal blood count

To investigate the influence of glucocorticosteroid therapy on the neonatal blood count, the haematologic data of 68 preterm and term infants, who had received a single dose of 1 mg dexamethasone i.v., were reviewed. White blood cell (WBC) count and platelet count increased after steroid therapy. The increase in WBCs was associated with an increase in the number of neutrophilic granulocytes, whereas the number of eosinophils decreased. We conclude that glucocorticosteroids after the neonatal blood count and influence its value as a diagnostic marker for bacterial infections.     

An assessment of registrars and their training programmes at the University of Cape Town Teaching Hospitals

In order to describe the registrar population and to highlight their problems, a study using an anonymous questionnaire was conducted in August 1988 at the University of Cape Town Group of Teaching Hospitals. The average age of respondents was 32 years and the majority had family responsibilities (60% married, 41% with dependents). They had significant medical experience and postgraduate qualifications. Registrars work long hours (mean 66 +/- 13.7 h/wk), with duty shifts that can extend for up to 34 hours. Most of their time at work was devoted to patient care, with time for study and research virtually non-existent. Although the majority (61%) felt that the 'registrar experience' was worthwhile, a significant proportion of respondents (45%) had considered leaving the rotation. The study revealed several shortcomings that need to be addressed if candidates of good calibre are to be attracted, academic standards are to be maintained and sufficient specialists produced to serve the needs of our population adequately.     

Human balance and posture control during standing and walking

The common denominator in the assessment of human balance and posture is the inverted pendulum model. If we focus on appropriate versions of the model we can use it to identify the gravitational and acceleration perturbations and pinpoint the motor mechanisms that can defend against any perturbation.

We saw that in quiet standing an ankle strategy applies only in the A/P direction and that a separate hip load/unload strategy by the hip abd/adductors is the totally dominant defence in the M/L direction when standing with feet side by side. In other standing positions (tandem, or intermediate) the two mechanisms still work separately, but their roles reverse. In the tandem position M/L balance is an ankle mechanism (invertors/evertors) while in the A/P direction a hip load/unloading mechanism dominates.

During initiation and termination of gait these two separate mechanisms control the trajectory of the COP to ensure the desired acceleration and deceleration of the COM. During initiation the initial acceleration of the COM forward towards the stance limb is achieved by a posterior and lateral movement of the COP towards the swing limb. After this release phase there is a sudden loading of the stance limb which shifts the COP to the stance limb. The COM is now accelerated forward and laterally towards the future position of the swinging foot. Also M/L shifts of the COP were controlled by the hip abductors/adductors and all A/P shifts were under the control of the ankle plantar/dorsiflexors. During termination the trajectory of both COM and COP reverse. As the final weight-bearing on the stance foot takes place the COM is passing forward along the medial border of that foot. Hyperactivity of that foot's plantarflexors takes the COP forward and when the final foot begins to bear weight the COP moves rapidly across and suddenly stops at a position ahead of the future position of the COM. Then the plantarflexors of both feet release and allow the COP to move posteriorly and approach the COM and meet it as quiet stance is achieved. The inverted pendulum model permitted us to understand the separate roles of the two mechanisms during these critical unbalancing and rebalancing periods.

During walking the inverted pendulum model explained the dynamics of the balance of HAT in both the A/P and M/L directions. Here the model includes the couple due to the acceleration of the weight-bearing hip as well as gravitational perturbations. The exclusive control of A/P balance and posture are the hip extensors and flexors, while in the M/L direction the dominant control is with the hip abductors with very minor adductor involvement. At the ankle the inverted pendulum model sees the COM passing forward along the medial border to the weight-bearing foot. The model predicts that during single support the body is falling forward and being accelerated medially towards the future position of the swing foot. The model predicts an insignificant role of the ankle invertors/evertors in the M/L control. Rather, the future position of the swing foot is the critical variable or more specifically the lateral displacement from the COM at the start of single support. The position is actually under the control of the hip abd/adductors during the previous early swing phase.

The critical importance of the hip abductors/adductors in balance during all phases of standing and walking is now evident. This separate mechanism is important from a neural control perspective and clinically it focuses major attention on therapy and potential problems with some surgical procedures. On the other hand the minuscule role of the ankle invertors/evertors is important to note. Except for the tandem standing position these muscles have negligible involvement in balance control.