The pharmacological effects of the anesthetic alfaxalone were evaluated after intramuscular (IM) administration to 6 healthy beagle dogs. The dogs received three IM doses each of alfaxalone at increasing dose rates of 5 mg/kg (IM5), 7.5 mg/kg (IM7.5) and 10 mg/kg (IM10) every other day. Anesthetic effect was subjectively evaluated by using an ordinal scoring system to determine the degree of neuro-depression and the quality of anesthetic induction and recovery from anesthesia. Cardiorespiratory variables were measured using noninvasive methods. Alfaxalone administered IM produced dose-dependent neuro-depression and lateral recumbency (i.e., 36 ± 28 min, 87 ± 26 min and 115 ± 29 min after the IM5, IM7.5 and IM10 treatments, respectively). The endotracheal tube was tolerated in all dogs for 46 ± 20 and 58 ± 21 min after the IM7.5 and IM10 treatments, respectively. It was not possible to place endotracheal tubes in 5 of the 6 dogs after the IM5 treatment. Most cardiorespiratory variables remained within clinically acceptable ranges, but hypoxemia was observed by pulse oximetry for 5 to 10 min in 2 dogs receiving the IM10 treatment. Dose-dependent decreases in rectal temperature, respiratory rate and arterial blood pressure also occurred. The quality of recovery was considered satisfactory in all dogs receiving each treatment; all the dog exhibited transient muscular tremors and staggering gait. In conclusion, IM alfaxalone produced a dose-dependent anesthetic effect with relatively mild cardiorespiratory depression in dogs. However, hypoxemia may occur at higher IM doses of alfaxalone.
During tumor cell invasion, certain extracellular matrix (ECM) components such as hyaluronan (HA) are degraded into small oligosaccharides, which are detected in patients. We previously reported that such HA oligosaccharides induce the proteolytic cleavage of an ECM-binding molecule CD44 from tumor cells and promote tumor cell migration in a CD44-dependent manner. Here, we report that chondroitin sulfate E (CSE), another component of the tumor ECM, strongly enhances CD44 cleavage and tumor cell motility when degraded into oligosaccharides. CSE and its degradation products were detected in pancreatic ductal adenocarcinoma. In CD44-expressing pancreatic tumor cells, degraded forms of CSE but not intact CSE enhanced CD44 cleavage; enzymatic digestion of such low-molecular weight CSE (LMW-CSE) abrogated this enhancement. Among the LMW-CSE preparations examined, 3-kDa CSE most potently induced CD44 cleavage. Nuclear magnetic resonance analysis showed that the 3-kDa-CSE bound to CD44, and that blocking such binding abrogated the CD44 cleavage induction. LMW-CSE also induced prominent filopodia formation and cytoskeletal changes in tumor cells; these effects were also abrogated by blocking the LMW-CSE binding to CD44. Chemically synthesized CSE hexasaccharides also enhanced the CD44 cleavage and tumor cell motility in a CD44-dependent manner. We conclude that the degraded forms of CSE modulate cell adhesion and migration by interacting with tumor-cell CD44, suggesting that the degradation products of tumor-associated ECMs that interact with CD44 play a significant role in CD44-mediated tumor progression. [Cancer Res 2008;68(17):7191-9]
Imidazolium ion-terminated self-assembled monolayer (SAM)-modified electrodes achieve CO2 conversion while suppressing hydrogen evolution. Immobile imidazolium ion on gold (Au) electrodes reduce CO2 at low overpotential. The distance between electrode and imidazolium ion separated by alkane thiol affects CO2 reduction activity. CO2 reduction current depends on the tunnel current rate. Although the product of CO2 reduction at the bare Au electrode is CO, SAM-modified electrodes produce ethylene glycol in aqueous electrolyte solution without CO evolution. The faradaic efficiency reached a maximum of 87%. CO2 reduction at SAM-modified electrodes is unaffected by reduction activity of Au electrode. This phenomenon shows that the reaction field of CO2 reduction is not the electrode surface but the imidazolium ion monolayer.
Chondroitin polymerization was first demonstrated in vitro when human chondroitin synthase (ChSy) was coexpressed with human chondroitin polymerizing factor (ChPF), which is homologous to ChSy but has little glycosyltransferase activity. To analyze the biological function of chondroitin, the Caenorhabditis elegans ortholog of human ChSy (sqv-5) was recently cloned, and the expression of its product was depleted by RNA-mediated interference (RNAi) and deletion mutagenesis. Blocking of chondroitin synthesis resulted in defects of cytokinesis in early embryogenesis, and eventually, cell division stopped. Here, we cloned the ortholog of human ChPF in C. elegans, PAR2.4. Despite little glycosyltransferase activity of the gene product, chondroitin polymerization was demonstrated as in the case of mammals when PAR2.4 was coexpressed with cChSy in vitro. The worm phenotypes including the reversion of cytokinesis, observed after the depletion of PAR2.4 by RNAi, were very similar to the cChSy (sqv-5)-RNAi phenotypes. Thus, PAR2.4 in addition to cChSy is indispensable for the biosynthesis of chondroitin in C. elegans, and the two cooperate to synthesize chondroitin in vivo. The expression of the PAR2.4 protein was observed in seam cells, which can act as neural stem cells in early embryonic lineages. The expression was also detected in vulva and distal tip cells of the growing gonad arms from L3 through to the young adult stage. These findings are consistent with the notion that chondroitin is involved in the organogenesis of the vulva and maturation of the gonad and also indicative of an involvement in distal tip cell migration and neural development.
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