A xanthine oxidase inhibitor 1'-acetoxychavicol acetate inhibits azoxymethane-induced colonic aberrant crypt foci in rats

The modifying effect of dietary administration of a xanthine oxidase inhibitor 1'-acetoxychavicol acetate (ACA) present in an edible plant Languas galanga in Thailand on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) was investigated in rats. Male F344 rats were given s.c. injections of AOM (15 mg/kg body wt) once a week for 3 weeks to induce colonic ACF. They were fed the diets containing 100 or 200 ppm ACA for 5 weeks, starting 1 week before the first dosing of AOM. At the termination of the study (week 5), AOM induced 118 +/- 28 ACF/colon. Dietary administration of ACA caused significant reduction in the frequency of ACF (41% inhibition by 100 ppm ACA feeding and 37% inhibition by 200 ppm ACA feeding, P<0.01). Such inhibition might be associated with suppression of the proliferation biomarkers' expression such as ornithine decarboxylase activity in the colonic mucosa, number of silver-stained nucleolar organizer regions' protein in the colonic mucosal cell nuclei and blood polyamine content. These results indicate that ACA could inhibit the development of AOM-induced ACF through its suppression of cell proliferation in the colonic mucosa and ACA might be a possible chemopreventive agent against colon tumourigenesis.     

An adjustable-current swimming pool for the evaluation of endurance capacity of mice

A new forced-swimming apparatus for determining maximum swimming time in mice was devised for use in the evaluation of the endurance capacity of Std and ddY and CDF1 mice after various diet and drug treatments. With the apparatus, a water current is generated by circulating water with a pump in a swimming pool. A spout and suction slit were contrived to generate a constant current while the strength of the current is regulated by a valve. The decrease in the leg-kicking intervals of mice accompanying the increase in the current speed confirmed that the workload is adjustable by regulation of the current speed. Compared with the number of forelimb strokes, that of the hindlimb kicks was greater. The swimming time until fatigue was observed to decrease with increasing current speed in the two strains of mice. As biochemical indexes, the blood lactate and muscle glycogen levels corroborated the correlation between current speed and increase in workload. These results indicate that the apparatus employed in the present study is suitable for the evaluation of the endurance capacity of mice and that is useful for detecting the effects of dietary differences and drug pretreatments on this capacity.     

Rat parathyroid gland, with special reference to its blood vascular bed, pericapillary space and intercellular space

The blood vascular bed, perivascular space and intercellular space of the rat parathyroid gland were studied using scanning electron microscopy of vascular casts, freeze-cracked tissue samples, and NaOH-digested tissue blocks. The findings were supplemented by transmission light and electron microscopy of iron colloid-treated or enzyme-digested tissue sections. The rat parathyroid gland contained a rich network of capillaries. These capillaries were surrounded by marked pericapillary spaces which were demarcated by basal lamina of both capillaries and parenchymal cells. The pericapillary spaces contained numerous collagen fibrils, and issued many crista-like projections which ran deep into the sheets of parenchymal cells. The intercellular spaces of parenchymal cells contained neither basal lamina nor collagen fibrils. The surfaces of the parenchymal cells showed strong negative charging, and maintained the intercellular spaces. The luminal surfaces of the capillary endothelium also showed strong negative charging, and maintained the capillary lumen.     

Preventive control based on complex-valued load-flow technique to avoid voltage instability in power systems

This paper presents a method for obtaining preventive control strategies based on nonlinear optimization for power systems which will incur voltage instability when load demand increases. An algorithm is proposed to determine an appropriate and effective control action taking into account the operating constraints to widen the margin between the present operating point and a voltage collapse point, thereby improving the system state. The method proposed here is based on a complex-valued load-flow technique using the Newton-Raphson method which has been developed already by the authors. Consequently, the preventive control algorithm also can evaluate the voltage instability in the event the present operating point becomes closer to the critical point and the system state becomes unfeasible at increased loading point. Further, in optimization, two-types of objective functions are introduced so that voltage stabilization and dissolution of constraint violation can be attained simultaneously. In addition, this paper discusses the extension of the proposed preventive control to the successive control method which carries out the control action to avoid voltage collapse while the load demand is increasing. Numerical examples for various model systems demonstrate the effectiveness of the proposed method.     

A protein kinase, PKN, accumulates in Alzheimer neurofibrillary tangles and associated endoplasmic reticulum-derived vesicles and phosphorylates tau protein

A possible role for a protein kinase, PKN, a fatty acid-activated serine/threonine kinase with a catalytic domain homologous to the protein kinase C family and a direct target for Rho, was investigated in the pathology of Alzheimer's disease (AD) using a sensitive immunocytochemistry on postmortem human brain tissues and a kinase assay for human tau protein. The present study provides evidences by light, electron, and confocal laser microscopy that in control human brains, PKN is enriched in neurons, where the kinase is concentrated in a subset of endoplasmic reticulum (ER) and ER-derived vesicles localized to the apical compartment of juxtanuclear cytoplasm, as well as late endosomes, multivesicular bodies, Golgi bodies, secretary vesicles, and nuclei. In AD-affected neurons, PKN was redistributed to the cortical cytoplasm and neurites and was closely associated with neurofibrillary tangles (NFTs) and their major constituent, abnormally modified tau. PKN was also found in degenerative neurites within senile plaques. In addition, we report that human tau protein is directly phosphorylated by PKN both in vitro and in vivo. Thus, our results suggest a specific role for PKN in NFT formation and neurodegeneration in AD damaged neurons.     

Common dimensions in the assessment of competence in school-aged girls.

In this research we investigate the competence construct, its structure, and the interrelations among assessments of children's competence provided by different observers. These questions were investigated in a sample of 76 girls 8 to 11 years of age. The results of bivariate correlations showed that there were statistically significant relations of moderate size between subscales of the self-rated Perceived Competence Scale for Children (PCSC; Harter, 1982) and the maternal-rated Social Competence measure of the Child Behavior Checklist (CBC; Achenbach & Edelbrock, 1981, 1983). Two dimensions emerged from an interbattery factor analysis. The dimensions assessed interpersonal competencies and competencies in the academic-cognitive domains. Physical-athletic competencies were not found to define important dimensions for this sample of girls. We discuss suggestions about a differentiated consideration of competence and possible gender differences in the assessment of competence, along with two alternative models suggested by this work for studying the stress-buffering role played by competence measured from several perspectives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural characterization of 1,2-polybutadiene by 13C n.m.r. spectroscopy: 1. Signal assignment in hydrogenated polybutadienes

The configurational sequences of 1,2-unit in a series of hydrogenated syndiotactic 1,2-polybutadienes were investigated in relation to the sequence distribution of 1,2- and 1,4-units. The signals at 10.20–10.94 ppm were assigned to the methyl carbons in the isolated 1,2-unit, the 1,2-1,2 dyad sequence flanked by 1,4-unit, and the 1,2-1,2-1,2 triad sequence, in order of increasing magnetic field. The splittings due to the configurational sequences were observed in the signals, reflecting the dyad and triad sequences of the 1,2-unit, which were assigned by considering the relative intensity of the signals and also the chemical shifts of model polymers.