Material und Struktur von Drainagen

The long history of surgical drainages stands in contradiction to available and reliable data. As of today, closed systems made of silicone are preferable.Taking possible complications into consideration and the good results of routine operations without drainages, indication for use should be critically evaluated. Interdisciplinary research,however, offers the chance of optimizing material and surface characteristics, biostability, biocompatibility, and flow rates.New drainages with improved performance and reduced side effects may counteract the current tendency to do without.     

Long-Term Deterioration of Kidney Allograft Function

Although long-term survival after kidney transplantation is critically dependent on maintaining stable allograft function, few studies have examined renal allograft function over time. Using pooled data from 10 278 consecutive transplants at five centers, we calculated slopes of estimated glomerular filtration rates (eGFR) measured after 1, 6 and 12 months in 9515, 8861 and 7359 patients surviving > or =1, > or =6 and > or =12 months, respectively. Slopes of eGFR progressively diminished for patients transplanted during 1984-1989, 1990-1993, 1994-1998 and 1999-2002 (analysis of variance p < 0.0001 and p = 0.1245 for slopes measured after 1 and 6 months, respectively). Slopes measured after 12 months were less in the most recent era: -2.2 +/- 7.2 mL/min/1.73 m(2)/year, -2.3 +/- 6.6 mL/min/1.73 m(2)/year, -2.4 +/- 7.4 mL/min/1.73 m(2)/year and -1.4 +/- 10.9 mL/min/1.73 m(2)/year, respectively, p = 0.0058. Slopes measured after 1, 6 and 12 months each were less for transplantations during 1999-2002, after adjusting for multiple transplantation characteristics (p < 0.0001). Similarly, in Cox proportional hazards analysis, the risk (95% CI) for a 25% reduction in eGFR was 0.92 (0.85-1.01), p = 0.0736 during 1990-1994; 0.94 (0.82-1.08), p = 0.4111 during 1995-1998 and 0.78 (0.64-0.95), p = 0.0110 during 1999-2002 (compared to 1984-1989). We conclude that the rate of decline in allograft function after kidney transplantation has improved, suggesting that stable, long-term function may be achievable.     

Acute renal failure due to bilateral ureteral obstruction by metastases from breast cancer

Two female patients with metastatic breast carcinoma had acute renal failure secondary to metastatic ureteral obstruction. Retrograde pyelography showed bilateral segmental constriction and dilatation of the ureters with hydronephrosis. Drainage procedures reversed the renal failure in both patients. A review of the literature indicates that ureteral involvement is frequent in patients with malignancies.     

Advances in noninvasive bone measurement

Several noninvasive measurement methods are used for evaluation of metabolic disease. Single-photon (¹²⁵I) scans of the peripheral skeleton are useful in some diseases but are ineffective in osteoporosis (even on the distal radius or os calcis) because they cannot predict spinal or femoral density. Also, peripheral measurements show high percentages of false negatives, that is many patients with fractures have normal peripheral density. Dual-photon (¹⁵³Gd) scans of the spine, femur, and total skeleton are precise and accurate (2% error) and provide direct measurements of bone strength at fracture sites. This gives the best discrimination of abnormality and the most sensitive monitoring. Quantitative computed computed tomography (QCT) allows measurement of the spine but not the critical proximal femur area. QCT has a large accuracy error because (a) the limited are measured (under 5 cm³) fails to represent the total vertebral body, (b) technical errors and (c) variable fat and osteoid influence the results. From the Fifth Southern Biomedical Engineering Conference, Louisiana State University Medical Center, Shreveport, LA 71130, October 20 and 21, 1986     

Role of calcium channel blocking agents in the prevention of atherosclerosis

Calcium channel blocking agents, although effective and widely used in the symptomatic therapy of hypertension and ischemic heart disease, have an uncertain effect on the development of coronary atherosclerosis, plaque rupture, and postrupture thrombosis. Both nifedipine and nicardipine have been shown to prevent the development of new coronary lesions but not the progression of existing lesions in prospective randomized angiographic studies. Verapamil, in contrast, failed to prevent the development of new coronary lesions and had no significant effect on the progression of existing lesions. Diltiazem, although not studied in patients with coronary atheroscleroses, has been shown to prevent the development of post-transplant coronary vascular disease. Despite the beneficial effects of nifedipine and nicardipine on new coronary lesion development, they have not been shown to reduce the incidence of recurrent ischemic events or mortality in the prospective randomized studies that demonstrated their effect on new coronary lesion development. A relatively new dihydropyridine calcium channel blocking agent, amlodipine, is hypothesized to prevent atherosclerosis due to its calcium channel blocking properties as well as by mechanisms independent of its calcium channel blocking properties. This agent has been selected for evaluation in the Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT) to explore whether the use of amlodipine over 3 years will reduce the incidence of early atherosclerotic lesions and, possibly, the progression of existing lesions in both the coronary and carotid arterial beds. Amlodipine could play an important future role in the secondary prevention of ischemic heart disease, but further study and a demonstration of a beneficial effect on recurrent ischemic events is required before any final conclusions concerning its effectiveness are reached.     

Diverse carotenoids protect against chemically induced neoplastic transformation

The ability of diverse carotenoid to inhibit methylcholanthrene-induced transformation of 10T1/2 cells has been investigated. When delivered using tetrahydrofuran as a novel solvent, all carotenoids were absorbed by cultured cells. When continuously administered to methylcholanthrene-treated cultures 7 days after removal of the carcinogen, canthaxanthin, beta-carotene, alpha-carotene and lycopene inhibited the production of transformed foci in a dose-dependent manner in the above order of potency. This activity was not associated with drug toxicity or antiproliferative effects. Renierapurpurin and bixin did not inhibit transformation at concentrations less than or equal to 10(-5) M. Lutein was inhibitory at 10(-5) M, but was inactive at lower concentrations. Because of differences in stability in culture medium (alpha-carotene less than beta-carotene less than canthaxanthin less than lycopene less than lutein) and structure, cellular levels of drug differed up to 8-fold after administration of identical concentrations of compounds. Carotenoids with polar groups achieved highest cellular levels, however cellular uptake did not correlate with activity. For example, lutein, the most polar and most stable, reached the highest concentration in cells yet required a concentration of 10(-5) M for activity in the transformation assay, while alpha-carotene, the least stable and least concentrated by cells, was comparably active at 3 X 10(6) M. alpha-Tocopherol, a potent lipid-phase antioxidant, was as active as lycopene in the transformation assay but at a 10-fold higher concentration did not approach the activity of beta-carotene or canthaxanthin. Because the most potent of the carotenoids tested (i.e. beta-carotene, alpha-carotene, canthaxanthin) all have the potential for conversion to retinoids (though this has never been demonstrated in mammals for canthaxanthin), it is suggested that these compounds have two components to their action; one related to their antioxidant properties, the other to their pro-vitamin A activities.     

Rewiring of Transcortical Projections to Middle Suprasylvian Cortex Following Early Removal of Cat Areas 17 and 18

Retrograde tracers were injected into middle suprasylvian (MS)cortex of two groups of experimental adult cats that had incurredremoval of visual areas 17 and 18 on either the day of birth(P1), or at 1 month of age (P28). Tracers were also injectedinto the same region of intact and adult ablated control cats.The locations and numbers of labeled neurons in the experimentaland control groups were compared. Following lesions on P1, butat no other age, increased numbers of neurons projected to MScortex. Virtually all of the additional neurons were locatedin the superficial layers of the ventral posterior suprasylvian(vPS) cortex. These results demonstrated that (1) neurons withipsilateral transcortical axons have the potential to reconfiguretheir projections after early, localized cortical damage elsewherein the cortex of the same hemisphere; (2) this reconfigurationinvolves expansion of specific projections and is not a generalizedcapacity of all cortical neurons; (3) the expansion is modalityspecific; and, finally, (4) the ability of cortical neuronsto reorganize projections is limited in time. The expanded projectionfrom vPS to MS cortex may contribute to neuronal compensationsand the sparing of visually guided behaviors previously demonstratedin cats with neonatal visual cortex damage, and is a testamentto the latent capacities immature cerebral cortical neuronspossess to establish new projections following restricted damageto the cerebral cortex early in life.