Brain Death Further Promotes Ischemic Reperfusion Injury of the Rabbit Myocardium

Background. Little is known about preload-dependent cardiac function after brain death (BD) and subsequent graft preservation.

Methods. A validated model of BD in rabbits was developed and myocardial performance was studied after BD induction and 1 hour of subsequent global hypothermic ischemia using a validated rabbit model and an isolated work-performing heart preparation.

Results. Significant decreases in stroke work, left ventricular contractility, and left ventricular relaxation were observed 2 hours after BD. After global hypothermic ischemia, significant decreases in stroke work, left ventricular contractility, and left ventricular relaxation were observed in the BD group compared with controls. Cardiac output and coronary flow were also significantly decreased in BD hearts compared with controls. Creatine kinase release was increased by 32.5% in BD hearts compared with controls.

Conclusions. In a rabbit model, BD combined with global hypothermic ischemia causes a significant decrease in left ventricular function compared with global hypothermic ischemia. This dysfunction may be attributed to a significant decrease in coronary flows in BD hearts.     

Ecology of a Southern Ohio stream receiving fly ash pond discharge: Changes from acid mine drainage conditions

Prior to 1975, Stingy Run was a third-order tributary of Kyger Creek, which empties into the Ohio River at Mile 260 (Gallia County, Ohio). Both streams drained strip mine refuse areas and physicochemical measurements indicated acidicmine drainage conditions (e.g., low pH). A depauperate macroinvertebrate community, dominated by a few acid-tolerant taxa, was found in both streams and no fishes were collected. In 1974, Stingy Run was impounded to form a fly ash pond which contains fly ash sluiced from Ohio Power Company's General James M. Gavin coal-fired power plant. Physicochemical and biological sampling during 1975–1986 indicated marked changes in the aquatic ecology of Stingy Run between 1) pre-impoundment and post-impoundment conditions; and 2) effluent pH control treatments after impoundment. Fly ash discharge eliminated acidicmine drainage characteristics in Stingy Run and lower Kyger Creek. After impoundment, net spinning caddisflies and a few dipteran taxa dominated the Stingy Run benthic community, reflecting changes in functional niches likely due to improved habitat and greater food availability. Replacement of acid feed by CO₂ injection for effluent pH control and changes in ash pond chemistry occurred concomitant with elimination of a substrate floc; increased species richness and densities of invertebrates were subsequently observed. In Stingy Run, species richness and diversity of fishes increased from 1983 to 1986, reflecting improved water quality and increased benthic production after impoundment. Many of these fishes are opportunistic feeders on drifting insects.     

Relative bioavailability of four controlled-release nifedipine products

Four controlled-release nifedipine products were investigated in two clinical studies. In study 1, 22 healthy male volunteers took part in an open, multiple-dose, randomized, crossover study to determine the relative bioavailablity of two 10 mg controlled-release nifedipine tablet (Adalat® Retard, Bayer), administered 12 hourly, and one 20 mg controlled-release nifedipine tablet (Adalat® Retard, Bayer) administered 12 hourly. In study 2, 24 healthy male volunteers took part in an open, multiple-dose, randomized, three-period, crossover study to determine the relative bioavailability of (i) two 30 mg nifedipine gastro-intestinal therapeutic system (GITS) tablets (Adalat® XL, Bayer) administered once daily; (ii) one 60 mg nifedipine GITS tablet (Adalat® XL, Bayer) administered once daily; and (iii) one 20 mg plus one 10 mg nifedipine controlled-release tablet (Adalat® Retard, Bayer), administered 12 hourly. In both studies detailed pharmacokinetic data, in particular with respect to the controlled-release characteristics of the different formulations, were collected. Results of both studies indicate that all nifedipine products investigated are bioequivalent with respect to the extent of absorption of nifedipine. The nifedipine GITS products (Adalat® XL) have better controlled-release properties than the Adalat® Retard product, and are suitable for once-a-day administration.     

Obstructive urinary tract diseases and prenatal diagnosis. Timing of surgical correction]

The Authors are reviewing their experience of Obstructive Uropathies diagnosed and treated surgically in neonates, the last 8 years in their Institution. 67 cases were reviewed, in which 37 presented with ureteropelvic junction obstruction (UPJ). 13 with posterior urethral valves, 11 with primary megaureter and 6 with ureterocele. Prenatal ultrasonography allowed the diagnosis to be made in two third of the patients. UPJ is the most common obstructive uropathy observed. Posterior urethral valves the most severe because of high pulmonary and renal (dysplasia) complication rate. Surgery, when indicated, has no more complications to be expected than in general population, if oriented prophylactic measures are taken in the early peri- and postoperative period.     

Increased collagen IV layer in the basal membrane area of the capillaries in severe chronic venous insufficiency

Lipodermatosclerosis is a sign of severe chronic venous insufficiency. In this stage of CVI one can find capillary leakage of water and plasmaproteins which results in a higher capillary filtration rate. In skin biopsies the result of this process can be seen as a pericapillary halo. The group of Burnand recently described fibrinogen deposits in this area. We studied the capillaries and their surrounding tissue to determine the thickness of the collagen IV deposits. In severe CVI with lipodermatosclerosis a significant increase of the collagen IV layer was observed. Collagen IV thickness was measured by an index method. The collagen IV thickness for this purpose refers to the capillary diameter. It can be suggested that the increase of the venous pressure in the capillaries leads to leakage of several proteins and namely fibrinogen. As a result of the increase of fibrinogen the collagen IV layer becomes thicker which leads to a decreasing function of the capillaries. In this way an auto-amplification mechanism maintains CVI. An other explanation can be induction of collagen IV due to the high capillary pressure in CVI.     

R 75251, a new inhibitor of steroid biosynthesis

R 75251, a new imidazole derivative, inhibited the conversion of androgens to estrogens, of progestins to androstenedione and testosterone, and of 11-deoxycorticosterone to corticosterone in human placenta microsomes, subcellular fraction of rat testis, bovine adrenocortical mitochondria, in cultured rat granulosa, testicular and adrenal cells, respectively. In vitro, no effect on cholesterol synthesis and cholesterol side-chain cleavage was found at concentrations up to 10 microM. In rat granulosa cells, no effect on progesterone production was detected. In vitro, no effect on steroid radioligand binding was observed. In male volunteers, a single dose of 300 mg of R 75251 significantly lowered plasma testosterone and estradiol for 24 hours and increased plasma concentration of 17 alpha-hydroxyprogesterone and progesterone. As compared with ketoconazole high dose (600 mg b.i.d), R 75251 (300 mg b.i.d) was at least as efficacious as inhibitor of testosterone synthesis when studied during ACTH stimulation. In contrast to ketoconazole, R 75251 did not significantly affect circulating adrenal androgen levels in male volunteers. Precursors of gluco- and mineralocorticoids such as 11-deoxycortisol and 11-deoxycorticosterone accumulated more than after ketoconazole administration. The data show that the cytochrome P450-dependent aromatase, 17-hydroxylase/17,20-lyase, and 11-hydroxylase are the target enzymes for R 75251.     

Penile flow- and blood pressure index and the effective dose of intracavernous papaverine

A simple test to predict the outcome of intracavernous papaverine treatment would be helpful in the management of erectile dysfunction. Doppler studies of the flaccid penis were compared with the results of intracavernous injection of papaverine. There was no correlation between these two. Therefore Doppler studies of the flaccid penis are not appropriate to predict the effect of intracavernous injection.