Embryo nutrition and energy metabolism and its relationship to embryo growth, differentiation, and viability

Over the past decade there has been a resurgence of interest in the culture media used in clinical in vitro fertilization. Unfortunately, during this time more confusion than consensus appears to have developed regarding the composition of these media. In order to facilitate a clearer understanding of this field, it is important to understand the role of specific medium components and how their use is regulated by the embryo. The roles of the key nutrients glucose, pyruvate, lactate, and amino acids during the preimplantation period have therefore been presented. Analysis of how the embryo regulates the utilization of such nutrients has led to a clearer understanding of the embryo's requirements during the dynamic period of preimplantation development. From such information, sequential culture media have been developed along with novel noninvasive tests of embryonic viability. It is proposed that continued studies on the human embryo will lead to further improvements in embryo culture conditions and the optimization of viability assays, culminating in the ability to transfer single embryos for the majority of, if not all patients.     

Antihypertensive and metabolic effects of concomitant administration of terazosin and methyclothiazide for the treatment of essential hypertension.

The efficacy and safety of once-daily 2.5- or 5.0-mg methyclothiazide (MCTZ) added to once-daily 5.0-mg terazosin (TRZ) versus 5.0-mg TRZ alone was evaluated in this double-blind, multicenter study. All patients received TRZ during a 6-week titration period. Hypertensive patients (222) (mean blood pressure of 159/104 mm Hg) were randomized to one of three treatment groups: TRZ alone (N = 76); TRZ+MCTZ-2.5 mg (N = 74); and TRZ+MCTZ-5.0 mg (N = 72) for the 8-week double-blind period. Changes in the supine and standing SBP/DBP from preTRZ period were: TRZ alone (-4.8/-8.1 and -2.6/-6.1 mm Hg); TRZ+MCTZ-2.5 mg (-17.3/-12.4 and -16.0/-11.2 mm Hg); and TRZ+MCTZ-5.0 mg (-20.6/-14.4 and -23.3/-14.6 mm Hg). Blood pressure changes in the combination groups were significantly greater than those in the TRZ alone group. However, there were no statistically significant differences between the TRZ+MCTZ-2.5-mg and TRZ+MCTZ-5.0-mg groups. The combination of TRZ and MCTZ tends to mitigate the adverse effects on serum glucose, uric, potassium and lipids usually associated with thiazide diuretics. Thus, combination treatment that begins with TRZ and adds MCTZ is effective in lowering blood pressure without any significant adverse metabolic effects.     

Differentiation of muscle fiber types in the teleost Brachydanio rerio, the zebrafish

Summary The trunk musculature of adult zebrafishes contains three major fiber types: adult red, intermediate, and white; and two minor populations: red muscle rim and scattered intermediate fibers.In this paper, the post hatching development of these muscle fiber types was studied by means of immunohistochemistry, using anti-myosin sera. Just hatched larvae contain two muscle fiber populations: embryonic red and white which give rise to the red muscle rim and the intermediate fibers respectively. Adult red fibers arise post hatching as a new separate population with distinct myosin properties.The differentiation of these fiber types occurs within the first four weeks after fertilization, when the adult pattern of peripheral axon bundles has become established.Differences in the muscle fiber type composition between the midbody and the tail myotomes become apparent in two month old fries. The number of scattered intermediate fibers increases from rostral to caudal, the opposite holds for the red muscle rim fibers. The red and intermediate area is triangular in the midbody; in the tail part it is stretched out along the lateral surface of the myotomes. These changes are considered as adaptations to improve the efficiency of the swiming performance.     

Correlation between brain dopamine levels and 1-dopa activity in anti-Parkinson tests

The activity of l-dopa and dopamine in anti-oxotremorine and reserpine reversal tests in mice was compared with l-Dopa-induced changes in brain dopamine levels. Oxotremorine-induced tremors and hypothermia were prevented by both l-Dopa and dopamine despite the fact that only l-Dopa increased brain dopamine levels. Furthermore, a peripheral decarboxylase inhibitor that increased brain dopamine levels completely abolished the activity of l-Dopa in the oxotremorine test. Reserpine-induced ptosis was also reversed by l-Dopa and dopamine. However, reserpine-induced catatonia was reversed only by l-Dopa and was directly correlated with brain dopamine levels. Pretreatment with a peripheral decarboxylase inhibitor increased l-Dopa reversal of reserpine catatonia correlating with increased brain dopamine levels. Since oxotremorine-induced tremors and hypothermia as well as reserpine-induced ptosis can be influenced by peripheral drug effects, the reversal of reserpine induced catatonia appears to be the better model to use in a search for anti-Parkinson drugs.