Human endothelin converting enzyme-2 (ECE2): characterization of mRNA species and chromosomal localization.

Generation of the functionally pleiotropic members of the endothelin vasoactive peptide family is critically catalyzed by unique type II metalloproteases, termed endothelin converting enzymes (ECE). Isolation of human ECE-2 (EC 3.4.24.71) cDNAs revealed deduced open reading frames of 787 and 765 amino acids with approximately 60% identity with human ECE-1. Characterization of mRNA variants revealed mRNA structural diversity at the 5'-terminus. Two mRNA species exist containing distinct first and second exons. Furthermore, in one of these species, an in-frame deletion of the intracytoplasmic domain removed 29 amino acids. Because of the previously reported human genetic diseases ascribed to germline mutations of member genes of the endothelin family, ECE2 was localized in human chromosomes with fluorescence in situ hybridization and radiation hybrid mapping to 3q28-q29 and SHGC-20171/D3S1571, respectively.     

Possible participation of calmodulin in stimulation of leucine transport by concanavalin A in human lymphocytes

Stimulation of leucine uptake by addition of concanavalin A, mediated by increase of intracellular free Ca2+ concentration [( Ca2+]), in lymphocytes (Mitsumoto, Y., Sato, K. and Mohri, T. (1988) Biochim. Biophys. Acta 968, 353-358) was abolished by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) and chlorpromazine, which inhibited membrane hyperpolarization induced by the mitogen. Quinine (0.5-1 mM) completely inhibited the concanavalin A-induced hyperpolarization and extensively inhibited the induced stimulation of leucine uptake. Based on these results, we suggest that the stimulation of leucine uptake by concanavalin A is largely due to activation of the Ca2+-dependent K+ channel which reinforces negative potential of the plasma membrane and is regulated by calmodulin.     

Amine oxidase in unicellular microorganismsMethanosarcina barkeri andTetrahymena pyriformis

A comparison has been performed of catalytic properties of unicellular microorganism amine oxidases (AO) from two new enzyme sources, the bacteriumMethanosarcina barkeri and the infusoriaTetrahymena pyriformis. It was shown that the both studied AO deaminate tyramine, serotonin, and benzylamine, but do not deaminate histamine. The AO fromMethanosarcina barkeri catalyzes deamination of all three substrates at an identical rate, while the rate of tyramine deamination under effect of AO fromTetrahymena pyriformis is one order higher than the rate of serotonin deamination, and about two orders higher than the rate of benzylamine deamination. Based on the data of the substrate-inhibitor analysis, a suggestion was made about the existence of one center for the substrate binding in the AO of the studied bacterium, while several centers in the AO of the studied infusoria.     

A rapid colorimetric assay for heparinase activity.

A rapid, sensitive, assay for enzymes that degrade heparin is described. The procedure is based on the interference of heparin with color development during the interaction of protein with the dye Coomassie brilliant blue. The loss of this property when the glycosaminoglycan is degraded by heparinase can be used to quantify activity of the enzyme in pure form, or in complex biological samples such as tissue homogenates or serum. The assay is also suitable for studying dependence of heparinase activity under conditions such as varying pH and temperature.     

Angiography of the iliofemoral arteriovenous system supplying free groin flaps and free hypogastric flaps.

The circulatory anatomy of the iliofemoral region was elucidated by doing detailed angiography in 50 cases, and we classified the vessels into 4 types. In most cases, the s.c.i.a. predominated over the s.i.e.a. Therefore, it is probably better to plan free flaps supplied by this artery. This vessel usually arises approximately two or three fingerbreadths inferior to the intersection of the femoral artery and the inguinal ligament, and the skin flap should be designed in the area inferior and parallel to the inguinal ligament.     

Changes in plasma thyroid hormones, luteinizing hormone (LH), estradiol, progesterone and corticosterone of laying hens during a forced molt

1. Circulating concentrations of iodothyronines, luteinizing hormone(LH), estradiol(E2), progesterone and corticosterone were measured in hens before, during, and after a forced molt induced by fasting. 2. Corticosterone increased at the onset of molt, peaked at the maximal molt and returned to pre- and post-molt levels. LH, E2 and progesterone declined during the molt, and the decline was coincident with the cessation of egg production. 3. Thyroxine(T4), triiodothyronine (T3) and reverse triiodothyronine(rT3) increased during the molt. The increases of T4 and T3 were not abolished even if the forced molt was conducted in mild weather.