Sildenafil Prevents Cardiovascular Changes after Bone Marrow Fat Embolization in Sheep

Background: Sudden, intraoperative cardiovascular deterioration as a result of pulmonary embolization of bone marrow fat is a potentially fatal complication during total hip and knee arthroplasty, intramedullary nailing, and spine surgery. Anesthetic management is challenging in the presence of increased right ventricular afterload due to pulmonary hypertension. Selective pulmonary vasodilation may be an appropriate prophylactic or therapeutic measure. The effect of sildenafil (phosphodiesterase inhibitor) on cardiovascular deterioration after bone marrow fat embolization was therefore investigated.

Methods: Bone cement (polymethylmethacrylate) was injected into three lumbar vertebrae in 12 sheep. Invasive blood pressures and heart rate were recorded continuously until 60 min after the last injection. Cardiac output and arterial and mixed venous blood gas variables were measured at selected time points. Before the first cement injection, 6 animals received a bolus injection (0.7 mg/kg) of sildenafil, with continuous infusion (0.2 mg [middle dot] kg-1 [middle dot] h-1) thereafter. Postmortem lung and kidney biopsies were taken for semiquantitative analysis of intravascular fat.

Results: Fat embolism was associated with a transient increase (21 +/- 7mmHg) in pulmonary arterial pressure. A transient decrease in arterial blood pressure and temporary increases in central venous pressure and dead space were also observed. No significant changes in any cardiovascular variable were observed after fat embolism in the sildenafil group. There was significantly (P < 0.05) less intravascular fat in the lungs of the sildenafil (median count of 5 emboli per microscopic view) compared with the control group (median count of 1).     

The significance of individual patient characteristics for loading capacity and deformation of the proximal end of the femur

The influence of such individual characteristics as age, sex, morphological characteristics (CDD angle, length of femoral neck, total and medullary diameter and score on the Singh osteoporosis index) on the loading capacity and deformation of the proximal end of the femur were determined in this experimental study. In all, 341 femora taken from the cadavers of persons who had died at over 60 years of age were tested under alternating load in up to 4000 cycles and, if no instability occurred, also under static load. The loading capacity and deformation were compared. The loading capacity was significantly higher in male femora with (5441 +/- 257 N) than in female femora (4273 +/- 1850 N). The loading capacity also decreased with increasing age and with decreasing CCD angle and Singh index score (higher degree of osteoporosis). Because of the high standard deviation in each group these differences were not significant.     

Stimulation of protein phosphatase activity by insulin and growth factors in 3T3 cells.

Incubation of Swiss mouse 3T3-D1 cells with physiological concentrations of insulin resulted in a rapid and transient activation of protein phosphatase activity as measured by using [32P]phosphorylase a as substrate. Activation reached a maximum level (140% of control value) within 5 min of addition and returned to control levels within 20 min. The effect of insulin was dose-dependent with half-maximal activation occurring at approximately 5 nM insulin. This activity could be completely inhibited by addition of the heat-stable protein inhibitor 2, which suggests the presence of an activated type-1 phosphatase. Similar effects on phosphatase activity were seen when epidermal growth factor and platelet-derived growth factor were tested. These results suggest that some of the intracellular effects caused by insulin and growth factors are mediated through the activation of a protein phosphatase.     

Severe ciguatera poisoning in Madagascar: A case report

In a single outbreak on the East coast of Madagascar, more than 500 people, 98 of whom died, were poisoned by the flesh of a shark, Carcharhinus amboinensis. From clinical symptoms it can be concluded that this poisoning is due to ciguatera toxins. It is the first case of a severe outbreak caused by a shark, and it is the first case with a mortality rate of 20%.     

Intra- and interfraction breathing variations during curative radiotherapy for lung cancer.

BACKGROUND AND PURPOSE: This study aimed at quantifying the breathing variations among lung cancer patients over full courses of fractionated radiotherapy. The intention was to relate these variations to the margins assigned to lung tumours, to account for respiratory motion, in fractionated radiotherapy. MATERIALS AND METHODS: Eleven lung cancer patients were included in the study. The patients' chest wall motions were monitored as a surrogate measure for breathing motion during each fraction of radiotherapy by use of an external optical marker. The exhale level variations were evaluated with respect to exhale points and fraction-baseline, defined for intra- and interfraction variations respectively. The breathing amplitude was evaluated as breathing cycle amplitudes and fraction-max-amplitudes defined for intra- and interfraction breathing, respectively. RESULTS: The breathing variations over a full treatment course, including both intra- and interfraction variations, were 15.2mm (median over the patient population), range 5.5-26.7mm, with the variations in exhale level as the major contributing factor. The median interfraction span in exhale level was 14.8mm, whereas the median fraction-max-amplitude was 6.1mm (median of patient individual SD 1.4). The median intrafraction span in exhale level was 1.6mm, and the median breathing cycle amplitude was 4.0mm (median of patient individual SD 1.4). CONCLUSIONS: The variations in externally measured exhale levels are larger than variations in breathing amplitude. The interfraction variations in exhale level are in general are up to 10 times larger than intrafraction variations. Margins to account for respiratory motion cannot safely be based on one planning session, especially not if relying on measuring external marker motion. Margins for lung tumours should include interfraction variations in breathing.     

The effect of adjuvant combined chemo/immunotherapy on immunological parameters and clinical course in patients with breast carcinoma

In 61 breast cancer patients the effect of an combined adjuvant chemo-/immunotherapy with thymopentin (Timunox, Cilag) on different parameters of cell-mediated immunity (Leucocyte Migration Inhibition Test, serum level of tumor necrosis factor alpha, IL 2, Interferon alpha and distribution of lymphocyte subsets in the peripheral blood) and the clinical course of disease was evaluated and compared to patients receiving only chemotherapy. In cancer patients additionally treated with thymopentin an increase of the interferon alpha serum level could be observed, whereas the other parameters examined did not change. In the control group the percentage of T helper cells decreased under chemotherapy (p less than 0.05). Due to the short time of observation of 49 months until now no significant changes concerning the disease free interval and the time of survival between both groups could be found. Possibly the additional administration of thymopentin in breast cancer patients at least leads to a reduction of the immunosuppressive side effects of an adjuvant chemotherapy.     

Animal experiments for the evaluation of laserspectroscopy in the fetus during labor.

Laserspectroscopy with near-infrared light is newly available for clinical application. The equipment consists of a near-infrared data collection unit (NIRDCU) and a personal computer. Emission of laser light at wavelengths of 775, 805, 845 and 904 nm is provided by the four laser diodes of the NIRDCU. By analyzing changes of optical density during laser radiation, information is obtained regarding the intracellular redox state and relative changes of blood volume. During measurement with the system on the fetal scalp during delivery we were able to get a first impression of the method's potential. While the application of the laser sensors is still cumbersome, signals providing information of the relative changes of hemoglobin concentration, relative changes of blood volume and cytochrome aa3 seems achievable. Laserspectrophotometric monitors may become safe, low cost and portable instruments for the non-invasive assessment of the biochemical and biophysical status in the fetus.     

An anisotropy of human tactile sensitivity and its relation to the visual oblique effect

Summary The ability of humans to detect striated stimuli on the distal phalanges was found to be highly anisotropic. Observers were much more sensitive to stripes presented in the proximal-distal orientation than to stripes in any other orientation. This tactile anisotropy was contrasted with the well-known visual anisotropy in which sensitivity is greatest for stripes at the horizontal and vertical orientations. We suggest that both the tactile anisotropy and the visual anisotropy are caused by corresponding anisotropies in the distribution of preferred orientations of orientation-selective neurons with in the respective modalities.