THE POSSIBLE INVOLVEMENT OF TISSUE-TYPE PLASMINOGEN-ACTIVATOR IN LUTEOLYSIS OF RHESUS-MONKEY

Changes of plasminogen activators (PA) during different stages of development of the corpus luteum, and their possible physiological role in luteolysis were studied in rhesus monkeys. It was demonstrated for the first time that monkey corpus luteal cells not only produce PA, but that the function of the corpus luteum is also closely related to the activity of this enzyme system. Generally, the life span for a corpus luteum in monkey is approximately 14-16 days, its demise beginning thereafter. In the present study, we found that urokinase in the corpus luteum is higher on day 5 and day 10 after human chorionic gonadotrophin injection, while the tissue type (t) PA is mainly produced on day 13 when luteolysis may take place. Progesterone production remained high on day 5 and day 10 and decreased dramatically from day 13, indicating the important role of tPA but not urokinase (u) PA in suppressing luteal function. When purified tPA (but not uPA) monoclonal antibody was added to luteal cell culture to neutralize endogenously produced tPA activity, progesterone production in the cells was increased significantly. Interestingly, prolactin alone was capable of increasing PA production by luteal cells; prolactin together with luteinizing hormone, however, had a synergistic luteotrophic effect.

Changes of tissue endothelin-1 and nitric oxide synthase in a sheep model of large intestinal obstruction

Large intestinal obstruction (LIO) in farm animals can cause a ischaemic necrosis of intestinal tissue, eventually leading to death. The roles of endothelin-1 (ET-1) and nitric oxide (NO) are not well understood in the process of LIO, but evidence suggests that endothelial-derived mediators may participate. In the present study, ET-1 concentration and total nitric oxide synthase (NOS) activity were measured in heart, liver, pancreas, lung and kidney in a model of LIO in sheep. Our data demonstrated that ET-1 concentration and NOS activity were altered, with significant increases of ET-1 in heart, lung and kidney and of NOS activity in pancreas and kidney, but a marked decline of NOS activity in liver (p<0.05). It is postulated that these alterations in NOS activity and ET-1 concentration may contribute to the progressive loss of organ function, and finally lead to death in LIO in sheep.

Spectroscopic investigation of the function of aqueous 2-hydroxyethylmethacrylate/glutaraldehyde solution as a dentin desensitizer

Fourier-transform (FT)-Raman and -infrared (IR) spectroscopy were employed to investigate the function of the aqueous 2-hydroxyethylmethacrylate/glutaraldehyde solution (Gluma) as a desensitizer. 2-Hydroxyethylmethacrylate (HEMA), glutaraldehyde (GA), and the mixture of HEMA/GA (i.e. Gluma) were used to interact with dentin, collagen, hydroxyapatite (HAP), and bovine serum albumin (BSA) individually. All the interactions were monitored by an FT-Raman spectrometer. FT-IR spectroscopy was also used in this study. The results show that HEMA could be absorbed by dentin and collagen; GA could cross-link collagen and BSA; and when BSA was added to Gluma, polymerization of HEMA occurred. The results suggest that Gluma acts as a desensitizer whereby, first, GA reacts with part of the serum albumin in dentinal fluid, which induces a precipitation of serum albumin, then, second, a reaction of GA with serum albumin induces polymerization of HEMA. The function of Gluma as a desensitizer to block dentinal tubules occurs via these two reactions.

Identification, expression, function and localization of a DUF985 domain-containing hypothetical gene from amphioxus Branchiostoma belcheri

The progress in genome sequencing has led to an increasing submission of uncharacterized hypothetical genes with the domain of unknown function, DUF985, in GenBank, and none of these genes is related to a known protein. We therefore underwent an experimental study to identify the function of a DUF985 domain-containing hypothetical gene BbDUF985 (GenBank Accession No. AY273818) isolated from amphioxus Branchiostoma belcheri (B. belcheri). BbDUF985 was successfully expressed in both prokaryotic and eukaryotic systems, and its recombinant proteins expressed in both systems definitely exhibited an activity of phosphoglucose isomerase (PGI). Both tissue-section in situ hybridization and immunohistochemistry demonstrated that BbDUF985 was expressed in a tissue-specific manner, with most abundant levels in the hepatic caecum and ovary. In CHO cells transfected with the expression plasmid pEGFP-N1/BbDUF985, the fusion protein was targeted in the cytoplasm of CHO cells, suggesting that BbDUF985 is a cytosolic protein. In contrast, Western blotting indicated that BbDUF985 was also present in amphioxus humoral fluids, suggesting that it exists as a secreted protein as well. Our study provided a framework for further understanding the biochemical properties and physiological function of DUF985-containing hypothetical proteins in other species. (c) 2008 Elsevier Inc. All rights reserved.