Search

Histone acetylation has a central role in the control of gene expression, influencing transcriptional control of many genes, including tumor suppressor genes. PXD101 is a novel hydroxamate-type inhibitor of histone deacetylase activity that inhibits histone deacetylase activity in HeLa cell extracts with an IC(50) of 27 nM and induces a concentration-dependent (0.2-5 micro M) increase in acetylation of histone H4 in tumor cell lines. PXD101 is cytotoxic in vitro in a number of tumor cell lines with IC(50)s in the range 0.2-3.4 micro M as determined by a clonogenic assay and induces apoptosis. Treatment of nude mice bearing human ovarian and colon tumor xenografts with PXD101 (10-40 mg/kg/day i.p.) daily for 7 days causes a significant dose-dependent growth delay with no obvious signs of toxicity to the mice. Growth delay is also observed for xenografts of cisplatin-resistant ovarian tumor cells. A marked increase in acetylation of H4 is detected in blood and tumor of mice 3 h after treatment with PXD101. The inhibition of growth of human tumor xenografts in mice, with no apparent toxicity, suggests that PXD101 has potential as a novel antitumor agent. Furthermore, the ability to measure histone acetylation in blood samples could provide a suitable pharmacodynamic end point to monitor drug activity.

Understanding the cellular effects of flavonoid metabolites is important for predicting which dietary flavonoids might be most beneficial in vivo. Here we investigate the bioactivity in dermal fibroblasts of the major reported in vivo metabolites of quercetin, i.e. 3′-O-methyl quercetin, 4′-O-methyl quercetin and quercetin 7-O-β-d-glucuronide, relative to that of quercetin, in terms of their further metabolism and their resulting cytotoxic and/or cytoprotective effects in the absence and presence of oxidative stress. Uptake experiments indicate that exposure to quercetin led to the generation of two novel cellular metabolites, one characterized as a 2′-glutathionyl quercetin conjugate and another product with similar spectral characteristics but 1 mass unit lower, putatively a quinone/quinone methide. A similar product was identified in cells exposed to 3′-O-methyl quercetin, but not in the lysates of those exposed to its 4′-O-methyl counterpart, suggesting that its formation is related to oxidative metabolism. There was no uptake or metabolism of quercetin 7-O-β-d-glucuronide by fibroblasts. Formation of oxidative metabolites may explain the observed concentration-dependent toxicity of quercetin and 3′-O-methyl quercetin, whereas the formation of a 2′-glutathionyl quercetin conjugate is interpreted as a detoxification step. Both O-methylated metabolites conferred less protection than quercetin against peroxide-induced damage, and quercetin glucuronide was ineffective. The ability to modulate cellular toxicity paralleled the ability of the compounds to decrease the level of peroxide-induced caspase-3 activation. Our data suggest that the actions of quercetin and its metabolites in vivo are mediated by intracellular metabolites.

Parental awareness of adolescent substance use was investigated in a high school sample of 985 adolescents and their parents. Only 39% of parents were aware their adolescent used tobacco, only 34% were aware of alcohol use, and only 11% were aware of illicit drug use. There were no variables that differentiated aware from unaware parents for all substances. Greater parental awareness of alcohol and tobacco use occurred with older adolescents. High adolescent ratings of family communication combined with low parental ratings of family communication were also associated with greater parental awareness of alcohol and tobacco use. Better school grades predicted greater awareness of alcohol and illicit drug use. Single parents and blended families were more aware of tobacco and illicit drug use.

Purpose To examine the role of both positive and negative styles of self-control, and gender-role stereotypes in binge eating and problem drinking Method Participants were 428 adolescent boys and 555 girls from predominantly Anglo-Australian backgrounds who attended regional state schools in New South Wales, Australia. Students completed standardized questionnaires that assessed problem drinking, binge eating, self-control styles, and identification with gender-role stereotypes. ANOVA and post hoc Tukey tests were conducted to examine differences among adolescents who reported problems in binge eating, drinking, and both domains. Results Adolescents who reported eating and drinking problems also reported a high negative and a low positive sense of self-control coupled with self-identification with the traits that typically describe negative dimensions of gender-role stereotypes. Regardless of gender, problem drinking was mainly related to traits of negative masculinity (bossy, noisy aggressive, etc.) whereas binge eating was mainly related to negative femininity (shy, needs approval from others, etc.). Participants who reported eating and drinking symptoms recorded low scores on positive control, high scores on negative control, and also high scores on the negative dimensions of masculinity and femininity. Summary A negative and passive style of self-control coupled with an identification with negative dimensions of gender summarizes the type of self-regulation that is implicated in both binge eating and problem drinking, and co-morbid symptoms. There is a need for interventions working toward a more balanced gender self-concept and a positive sense of self-control.

Oxidative and nitrosative stress is increasingly associated with the pathology of neurodegeneration and aging. The molecular mechanisms underlying oxidative/nitrosative stress-induced neuronal damage are emerging and appear to involve a mode of death in which mitogen-activated protein kinase (MAPK) signaling pathways are strongly implicated. Thus, attention is turning towards the modulation of intracellular signaling as a therapeutic approach against neurodegeneration. Both endogenous and dietary agents have been suggested as potent modulators of intracellular signal transduction, e.g. nitric oxide and flavonoids, respectively. This review addresses recent findings on the biological effects of flavonoids and nitric oxide in neurodegeneration and aims to elucidate the rationale for their prospective use as modulators of cellular signal transduction.

Ca2+ influx through NMDA receptors can initiate molecular changes in neurones which may underlie synaptic plasticity, neuronal development, survival and excitotoxicity. Signalling through the MAP kinase (Erk1/2) cascade may be central to these processes. We previously demonstrated that Ca2+-permeable AMPA receptors activate Erkl/2 through a phosphatidylinositol 3-kinase (PI 3-kinase)-dependent mechanism. We now report that NMDA receptor activation of Erk1/2 was also blocked by inhibitors of PI 3-kinase (LY 294002, wortmannin). In addition, pre-treatment of neurones with pertussis toxin inhibited NMDA-induced Erk1/2 activation, indicating a role for heterotrimeric Gi/o proteins. PI 3-kinase directs activation of the serine-threonine kinase Akt (PKB). Treatment of striatal neurones with glutamate induced a rapid Ca2+-dependent and PI 3-kinase-dependent phosphorylation of Akt (Ser473), which was not blocked by the Mek inhibitors PD98059 or U0126. Targets for Erk1/2 and Akt pathways include transcription factors. Glutamate-induced phosphorylation of cAMP response element binding protein (CREB; Ser133) was partially blocked with either PD98059, U0126, LY294002 or wortmannin but was very strongly inhibited on co-application of LY294002 and PD98059. We propose that NMDA receptor stimulation can activate Erk1/2 and Akt signalling pathways in a PI 3-kinase dependent manner which may target CREB in the nucleus.

Introduction. To report on highlights of a longitudinal study of gamblers, the Alberta Leisure, Lifestyle, Lifecycle Project (LLLP) as well as comparisons with the Ontario Quinte Study. Method. Five LLL cohorts of gamblers (ages 13–15, 18–20, 23–25, 43–45, and 63–65) have been recruited through Random Digit Dialing (RDD) since February 2006. The cohorts are stratified by large and small urban centers and over-sampled for at-risk gamblers. Four data collections have occurred with initial telephone and face-to-face interviews, followed by web-based surveys. The selection of survey instruments reflected a biopsychosocial model of gambling. Results. Recruitment at Time 1: N = 1808 – Feb – Oct ′06; Time 2: N = 1495 – Nov ′07 – Jun ′08; Time 3: N = 1316 – Jul ′09 – Mar ′10; and Time 4: N = 1343 – Feb – Oct ′11. (Overall Retention Rate 75.1% – 20 deceased). In addition, N = 679 blood and saliva samples were collected. For comparison, the Quinte study had N = 4121 and a Retention Rate 90.4% over 5 time intervals. Highlights include. 1. an analysis of patterns of continuity/discontinuity of problem gambling over 5 years; 2. identification of variables best predicting future problem gambling, coordinated with the Quinte study. Conclusion. Longitudinal studies provide unique insights into the trajectory of gambling behaviors.

The present study was designed to increase our understanding of the co-morbidity between problem drinking and binge eating. The study investigated both consummatory behaviors in relation to restrained drinking, restrained eating, and a general measure of self-control. The participants were a sample of 658 boys and 414 girls aged between 14 and 17 years. The dimension of restraint, which best predicted the two problem behaviors when examined separately for both boys and girls, was cognitive and emotional preoccupation (CEP) about controlling one's consummatory intake. In addition, evidence was found linking both problem drinking and binge eating to restraint and poor general self-control. The struggle with self-control and the high emphasis on CEP about controlling one's consummatory intake, which characterise restrained drinking and restrained eating, closely resembles Baumeister and Heatherton's notion of misregulation [Psychol. Inquiry 7 (1996) 1.]. Discussed are the similarities between restraint and misregulation, and the kinds of strategies that can be used to improve self-control.

Toine Spapens, Alan Littler and Cyrille Fijnaut, Leiden, Martinus Nijhoff, 2008, ISBN 978-90-04-172180 This book is produced by the Gambling Research Group associated with the Tilburg University's ...

Oxidative stress is implicated in neuronal loss associated with neurodegeneration such as in Parkinson's disease, Alzheimer's disease and age-related cognitive decline. Recent reports indicate that the consumption of flavonoid-rich fruits partly reverses the age-related neuronal and cognitive decline. In this study, cultured striatal neurons were exposed to oxidized lipids in the form of low-density lipoprotein (oxLDL) as a model for the induction of oxidative injury, and the abilities of phenolic antioxidants, flavonoids and hydroxycinnamic acid derivatives, to attenuate this neuronal damage were examined. OxLDL was demonstrated to enter neuronal cells and to be capable of eliciting neurotoxicity in a dose- and time-dependent manner, inducing DNA fragmentation and cell lysis. Flavonoids exert protective effects, which appear to be related to specific structural characteristics, particularly relevant being those defining their reduction potentials and partition coefficients. In summary, these data suggest a possible role for flavonoids in reducing neurodegeneration associated with chronic disorders in which oxidative stress is implicated.

Objective. The study investigated sex-role traits and self-monitoring styles as two dimensions of self-control amongst women with bulimia nervosa and normal controls. Design and methods. The participants were 30 women with bulimia nervosa and 40 normal controls who completed questionnaires, which assessed bulimic symptoms, sex-role traits, and Synder s Self-Monitoring Scale. Results. Women with bulimia nervosa were found to identify more strongly than controls with negative feminine traits and Other Directedness, a style of self monitoring that focuses on pleasing others. Conclusions. These findings reinforce the notion that women with bulimia nervosa lack assertiveness skills and that the strategies they have developed in their interactions with others can be described as a Negative Yielding style of self control.

The relationship between expectancies and other psychological constructs related to drinking is unclear. The current study assesses the power of drinking restraint, measured by the Temptation and Restraint Inventory (TRI), along with alcohol expectancy and drinking refusal self-efficacy, measured by the Drinking Expectancy Profile (DEP), as indicators of alcohol use and problem drinking.Volunteer students (N = 359), consisting of 113 men with a mean (+/-SD) age of 25.31 +/- 10.61 years and 246 women with a mean age of 23.04 +/- 8.90, completed the TRI, DEP and Alcohol Dependence Scale (ADS) as well as frequency and quantity measures of self-reported drinking.Drinking Restraint was a stronger indicator of higher scores on the ADS, accounting for 54% and 45% of the variance for men and women, respectively, with Alcohol Expectancies and Drinking Refusal Self-Efficacy being the better indicator of frequency of alcohol consumption, accounting for 20% of the variance for men and 26% for women. Both measures were represented by similar variances within the quantity of drinking measure.Drinking restraint and alcohol expectancies were seen to measure kindred but unique cognitive subsets, providing further insight into the progression of alcohol problems. Alcohol expectancies and drinking refusal self-efficacy may be acquired early in the development of drinking behavior, as evidenced by stronger associations with risky drinking; drinking restraint and its associated loss of control factors appear to be more specifically related to problem drinking. Alcohol expectancy and drinking refusal self-efficacy may thus have broader use in the assessment of drinking behavior.

To investigate knowledge about fetal alcohol syndrome (FAS) among Natives in northern Manitoba. A second objective was to determine if there are age or gender differences in level of knowledge. A third objective was to examine the relationship between knowledge about FAS and reported frequency of drug and alcohol use during pregnancy.A nonrandom sample of 466 Natives from northern Manitoba was interviewed about drug and alcohol use during pregnancy and knowledge of FAS. The sample was proportionately representative of the 26 northern reserves, with an approximately equal number of male and female subjects ranging in age from 13 to 71 years.Northern Manitoban Natives have lower levels of FAS knowledge than the general public. Of this sample, 80% believed drinking alcohol could adversely affect the unborn baby and 36% had heard of FAS, compared to 90% and 64%, respectively, in the general U.S. population. Natives in their 20s and 30s were more knowledgeable than Natives in their 50s and 60s. Females tended to be more knowledgeable than males. Drug and alcohol use during pregnancy is high (51% of women report drinking during one or more pregnancies) and the relationship between FAS knowledge and drug use during pregnancy appears weak. Young people were the most knowledgeable about FAS but also the most likely to report having used drugs or alcohol during pregnancy.The low levels of knowledge about FAS among the Native population supports the need for continued education. However, the results also suggest that education by itself may be insufficient to make dramatic changes in behavior.

The present study investigated problem drinking and symptoms of disordered eating in relation to (a) restrained drinking and eating, and (b) cognitive self-control. One hundred and ninety-eight high school students (97 males and 101 females; mean age = 16.45 years) completed questionnaires that assessed problem drinking, symptoms of disordered eating, restrained eating and drinking, and cognitive self-control. Using principal components analysis, three factors with eigenvalues greater than 1 were found to summarize the interrelationships among the examined measures. For both sexes, the first two factors primarily reflected problem drinking and restrained drinking, and problem eating and restrained eating, respectively. The third factor reflected a more general problem with control underlying aspects of both problem drinking and problem eating.

The relationship between gender-stereotypical traits and drinking behaviors was examined in 422 university students via both positive and negative measures of masculinity and femininity. Two canonical variates summarized the underlying relationships. The 1st canonical variate indicated that both high negative masculinity and low positive femininity predicted alcohol consumption and alcohol-related problems. This behavior was labeled confirmatory drinking because it depicts a style of drinking that reinforces gender-stereotypical images about alcohol use; masculine characteristics are typically associated with high levels of alcohol consumption. The 2nd canonical variate indicated that both low positive masculinity and low positive femininity predicted problem drinking. This behavior was labeled compensatory drinking because drinkers often use alcohol to express their masculinity and femininity. The distinction between confirmatory and compensatory drinking has important implications for the development of more effective education and preventative strategies.

The present study examined the relative importance of outcome expectancies and self-efficacy [1] in the prediction of alcohol dependence [2] and alcohol consumption in a sample of young adult drinkers drawn from a milieu previously reported as supportive of risky drinking. In predicting alcohol dependence, outcome expectancies were found to mediate self-efficacy and the same pattern was found for both males and females. This suggests that male and female drinkers may become more similar as they progress along the drinking continuum from risky drinking to dependent drinking. However, in women, in comparison to men, a greater array of expectancies and self-efficacy scales were found to predict heavy drinking, as measured by quantity and frequency. These results suggest that heavy drinking women are particularly at risk of developing drinking related complications and that preventative education needs to take into account gender differences.

The genetically epilepsy-prone rat is an animal model of inherited generalised tonic-clonic epilepsy that shows abnormal susceptibility to audiogenic seizures and a lowered threshold to a variety of seizure-inducing stimuli. Recent studies suggest a crucial role for glutamate and GABA transporters in epileptogenesis and seizure propagation. The present study examines the levels of expression of the messenger RNAs encoding the glial and neuronal glutamate transporters, GLT-1 and EAAC-1, and the neuronal GABA transporter, GAT-1, in paired male genetically epileptic-prone rats and Sprague Dawley control rats using the technique of in situ hybridization. In a parallel study, semiquantitative immunoblotting was used to assess GLT-1 and EAAC-1 protein levels in similarly paired animals. Animals were assessed for susceptibility to audiogenic seizures on six occasions, and killed seven days following the last audiogenic stimulus exposure. Rat brains were processed for in situ hybridization with radioactive 35S-labelled oligonucleotide probes (EAAC-1 and GAT-1), 35S-labelled riboprobes (GLT-1), and Fluorescein-labelled riboprobes (GLT-1 and GAT-1) or processed for immunoblotting using subtype-specific antibodies for GLT-1 and EAAC-1. Semiquantitative analyses were carried out on X-ray film autoradiograms in several brain regions for both in situ hybridization and immunoblotting studies. Reductions in GAT-1 messenger RNA were found in genetically epileptic-prone rats in all brain regions examined (-8 to -24% compared to control). Similar reductions in GLT-1 messenger RNA expression levels were seen in cortex, striatum, and CA1 (-8 to -12%) of genetically epileptic-prone rats; the largest reduction observed was in the inferior colliculus (-20%). There was a tendency for a reduced expression of EAAC-1 messenger RNA in most regions of the genetically epileptic-prone rat brain although this reached statistical significance only in the striatum (-12%). In contrast, no significant differences in GLT-1 and EAAC-1 protein between genetically epileptic-prone rats and control animals were observed in any region examined, although there was a tendency to follow the changes seen with the corresponding messenger RNAs. These results show differences in the messenger RNA expression levels of three crucial amino acid transporters. For the two glutamate transporters, GLT-1 and EAAC-1, differences in messenger RNA levels are not reflected or are only partially reflected in the expression of the corresponding proteins.

Hydrogen peroxide (H2O2) is a potent stimulator of signal-responsive phospholipase A2 (PLA2) in vascular smooth muscle and cultured endothelial cells. We investigated whether H2O2 plays a similar regulatory role in neurons. H2O2 did not stimulate a release of arachidonic acid from cultured neurons when applied alone but strongly enhanced the liberation of arachidonic acid evoked by maximally effective concentrations of either glutamate, the glutamate receptor agonist N-methyl-D-aspartate (NMDA), the muscarinic receptor agonist carbachol, the Na+-channel opener veratridine, or the Ca2+-ionophore ionomycin. The potentiating effects of H2O2 were strongly inhibited in the presence of the PLA2 inhibitor mepacrine, suggesting that the site of action was within the signal responsive arachidonic acid cascade. The enhancing effect of H2O2 was not reversed by protein kinase C inhibitors (chelerythrine chloride or GF 109203X) nor was it mimicked by phorbol ester treatment. H2O2 alone strongly enhanced the levels of immunodetectable activated mitogen-activated protein kinase (activated MAP kinases ERK1 and ERK2) in a Ca2+-dependent manner and this effect was additive with increases in the levels of activated MAP kinase evoked by glutamate. The enhanced release of arachidonic acid, however, was not clearly reversed by the MAP kinase kinase (MEK) inhibitor PD 98059, although this treatment effectively abolished H2O2 activation of MAP kinase. Thus, MAP kinase activation and Ca2+-dependent arachidonic acid release are regulated by oxidative stress in cultured striatal neurons.

Glutamate-evokes a Ca2+-dependent release of arachidonic acid from cultured neurones via the activation of NMDA and AMPA receptors. In this study we investigated whether exposing cultured striatal neurones either acutely or chronically to ethanol would modify these responses. Acute ethanol (100 mM, 15 min) inhibited the liberation of arachidonic acid evoked by a maximally effective concentration of glutamate, an affect which appeared to be mediated primarily by a reduction in NMDA receptor responsiveness. In contrast, chronic ethanol exposure caused a dose-dependent increase in the glutamate, N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) evoked release of arachidonic acid, although ethanol was less potent at the AMPA response. Basal responses were not altered by acute or chronic ethanol and the concentrations of ethanol employed were not toxic. Chronic ethanol (100 mM, 48 h) increased NMDA-mediated neuronal damage at sub-maximal concentrations of the agonist, suggesting that an enhanced mobilisation of arachidonic acid may underly the potentiated excitotoxic neuronal loss observed following exposure to ethanol.

Abstract —Arteriosclerotic lesions are characterized by the accumulation of T lymphocytes and monocytes and the proliferation of intimal smooth muscle cells. Expression of the chemokine monocyte chemoattractant protein-1 (MCP-1) has been observed in arteriosclerotic plaques and has been proposed to mediate the transendothelial migration of mononuclear cells. More recently, MCP-1 has been proposed to affect the proliferation and migration of vascular smooth muscle cells (VSMCs). We have used reverse transcription–polymerase chain reaction (RT-PCR) to investigate chemokine mRNA expression in human arteriosclerotic lesions obtained from surgical biopsy of diseased vascular tissue and show, in addition to MCP-1, expression of the chemokine macrophage inflammatory protein-1α (MIP-1α) at higher levels than in “normal” aortic tissue. We have also used RT-PCR to characterize the expression of known chemokine receptors by primary human VSMCs. Messenger RNA for the MIP-1α/RANTES receptor, CCR-1, and the MCP-1/MCP-3 receptor, CCR-2, was expressed by unstimulated VSMCs grown under serum-free culture conditions for 24 hours. The receptors CCR-3, CCR-4, CCR-5, CXCR-1, and CXCR-2 were not expressed by VSMCs. The presence of functionally coupled receptors for MIP-1α on VSMCs was demonstrated by specific binding of biotinylated MIP-1α and increases in intracellular Ca 2+ levels after exposure to this chemokine. Taken together, these results suggest that chemokines are likely to be involved in arteriosclerosis and may play a role in modulating the function of VSMCs in vivo.

The binding and functional activity of the CC chemokines monocyte chemoattractant protein-1 (MCP-1), MCP-2, and MCP-3 have been characterized using Chinese hamster ovary DXB-11 cells transfected with the chemokine receptor CCR2B. Receptor binding studies demonstrated that 125I-labeled MCP-1 bound to a single class of high-affinity receptors with a Kd of 0.14 (0.070.32) nM. In competition studies MCP-1, MCP-2, and MCP-3 completely inhibited 125I-labeled MCP-1 binding with Ki values of 0.3 (0.16-0.46), 8.8 (3.4-26), and 12.2 (0.6-22) nM, respectively. In calcium mobilization studies, MCP-1 and MCP-3 induced robust elevations in intracellular calcium concentrations, whereas MCP-2 was only weakly active. In contrast, using changes in extracellular acidification rate as a functional readout, all three chemokines were identified as potent agonists of CCR2B. These data demonstrate that MCP-2, in addition to MCP-1 and MCP-3, is a potent agonist of CCR2B and furthermore that MCP-2 activates either different or a subset of the signaling pathways activated by MCP-1 and MCP-3.

The present study was designed to test whether dietary restraint mediates the relationship between body dissatisfaction and bulimic eating patterns in a sample of 172 university females. Contrary to what was expected the results showed that body dissatisfaction mediated the relationship between dietary restraint and bulimic patterns of eating. Thus the results highlight the primary importance of body dissatisfaction as a predictor of bulimic behavior. Body dissatisfaction encompasses a broad array of dimensions such as self-perceptions, cognitions, affect and behavior and it carries enormous explanatory power but its different components remain largely unexplored.

Detailed studies of intense light - material interactions has led to new insights into fs laser induced refractive index change in a range of glass types. This body of knowledge enables the development of advanced processing methodologies, resulting in novel planar and 3D guided wave devices. We will review the chemistry and morphology associated with fs laser induced refractive index change in multi-component glasses such as ZBLAN, phosphates and silicates, and discuss how these material changes inform our research programs developing a range of active and passive lightwave systems. Refereed/Peer-reviewed

RP 73163 ((S)-2-[5-(3,5-dimethyl-l-pyrazolyl)pent-l-yl)-sulphinyl]-5, 6-diphenylimidazole) has been shown to be a potent and specific inhibitor of acyl-CoA:cholesterol acyltransferase (EC 2.3.1.26; ACAT) in vitro using the tissues of experimental animals as sources of the enzyme. The concentrations of RP 73163 required to produce 50% inhibition of ACAT activity (IC50 values) in microsomal preparations ranged from 86 nM for rat liver to 370 nM for rabbit intestine. In whole cell assays using human hepatic (HepG2), intestinal (Caco2), and monocytic (THP-1) cell lines, RP 73163 inhibited ACAT activity with IC50 values of 266, 158, and 314 nM, respectively. The addition of RP 73163 (0.03-1.0 microM) to the medium of cultured HepG2 cells produced a concentration-dependent decrease in apolipoprotein B (apoB) secretion. The compound has high systemic bioavailability. Using a bioassay, a concentration of active inhibitor equivalent to 29 microM of parent compound was present in plasma 1 hr after oral administration of RP 73163 (50 mg.kg-1). In rats that had been fed a basal diet ad libitum or starved for 18 hr prior to blood sampling, the administration of RP 73163 (50 mg.kg-1 b.i.d. for 7 days) reduced plasma triglyceride levels by 50% without affecting the concentration of cholesterol. This hypotriglyceridaemic effect was associated with reductions in plasma very-low-density-lipoprotein (VLDL) and low-density-lipoprotein (LDL) levels. RP 73163 decreased the rate of VLDL secretion by 24% in Triton WR-1339-treated rats that had been fasted overnight but did not affect the secretion rate in animals fed ad libitum, indicating that ACAT was only important in regulating VLDL secretion under certain nutritional conditions. RP 73163 reduced the accumulation of intraperitoneally administered [3H]leucine into the plasma VLDL-apoB pool in both fed and fasted states. The results suggest that, in fed animals at least, an increase in the clearance of VLDL from the bloodstream may contribute to the hypolipidaemic activity of the compound. In rabbits with casein-induced endogenous hypercholesterolaemia, RP 73163 specifically reduced the levels of cholesterol carried by LDL. In conclusion, the hypolipidaemic actions of RP 73163, a potent and systemically bioavailable ACAT inhibitor, are consistent with a reduction in the secretion of apoB containing lipoproteins by hepatic tissue and possibly with an increase in the clearance of these particles.

The joint, but not independent, activation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) and metabotropic glutamate receptors induces liberation of arachidonic acid from cultured mouse striatal neurones. We examined whether blocking AMPA receptor desensitisation with cyclothiazide would modify this response. Cyclothiazide strongly potentiated the combined AMPA/(1 S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD)-evoked release of arachidonic acid (EC50 of approximately 7 microM) but did not modulate the basal, ACPD, or NMDA response. The enhanced liberation of arachidonic acid, observed in the presence of cyclothiazide, was due to the appearance of a genuine AMPA response that was independent of an associative activation of metabotropic receptors. The potentiated and nonpotentiated AMPA responses were inhibited by both competitive [2,3-di-hydroxy-6-nitro-7-sulphamoylbenzo (f) quinoxaline] and 2,3-benzodiazepine noncompetitive (GYKI 53655 and GYKI 52466) receptor antagonists. Cyclothiazide was equally effective at potentiating the AMPA response in either the presence or absence of glucose, suggesting that the increased glutamate-evoked arachidonic acid release observed in these cells under conditions of glucose deprivation is not due to reduced AMPA receptor desensitisation. The enhanced liberation of arachidonic acid measured in the presence of cyclothiazide appeared to result from a large (fourfold) elevation of the AMPA-induced increase in intracellular calcium level. Therefore, an AMPA-evoked mobilisation of arachidonic acid could potentially contribute to non-NMDA receptor-mediated neurotoxicity, which has been observed in neuronal cells in the presence of cyclothiazide.

Glucose deprivation potentiates the glutamate receptor-evoked release of arachidonic acid from cultured mouse striatal neurons. In this study we investigated whether this potentiation would be modified by the end-products of glycolysis. These enhanced responses were completely reversed by the addition of increasing concentrations of either lactate or pyruvate. This reversal was not due to increased osmolarity as substituting sucrose for lactate or pyruvate did not mimic their effects. In contrast, in the presence of glucose, neither lactate nor pyruvate was effective. Furthermore, these monocarboxylic acids rescued neuronal respiration in the absence of glucose. Inhibiting glycolysis with iodoacetate in the presence of glucose reproduced the potentiated glutamate-evoked release of arachidonic acid observed following glucose deprivation and reduced neuronal respiration to the same extent as that observed in the absence of glucose. All of these effects were overcome by the addition of either lactate or pyruvate. The reversal of the potentiated glutamate-evoked release of arachidonic acid by lactate or pyruvate was inhibited by a specific inhibitor of monocarboxylic acid transport, alpha-cyano-4-hydroxycinnamic acid, suggesting that lactate and pyruvate act intracellularly. Therefore, we propose that the enhanced release of arachidonic acid evoked by glutamate during glucose deprivation results from reduced glycolysis and hence from a depletion of lactate or pyruvate.

The second in this series of papers concerns our further investigations into the search for a potent bioavailable acyl-CoA:cholesterol O-acyltransferase (ACAT) inhibitor suitable for the treatment of atherosclerosis. The design, synthesis, and structure-activity relationship for a series of ACAT inhibitors based on the 2-(1,3-dioxan-2-yl)-4,5-diphenyl-1H-imidazole pharmacophore are described. Compounds such as 13a bearing simple alkyl or hydroxymethyl substituents at the 5-position of the 1,3-dioxane ring are potent bioavailable inhibitors of the rat hepatic microsomal enzyme in vitro (IC50100 nM) but are only weak inhibitors of the human hepatic enzyme. We have found however that 1,3-dioxanes substituted at the 5-cis position with pyrazolylalkyl or aminoalkyl groups are potent inhibitors in vitro of human macrophage ACAT, the potency depending on the nature of the terminal heterocycle and the length of the alkyl chain. An ex vivo bioassay herein demonstrates that potent inhibitors such as 13t (IC50 = 10 nM) which contain lipophilic terminal heterocycles do not appear to be systematically available. Less potent but more water soluble compounds such as 13h (IC50 = 60 nM) and 13n (IC50 = 70 nM) are absorbed following oral dosing and achieve plasma levels significantly in excess of their IC50 for ACAT inhibition. These compounds are therefore possible candidates for further investigation as oral antiatherosclerotic agents.

1. This study investigated the effects of acute and chronic ethanol on basal, agonist- and forskolin-stimulated cyclic AMP formation in NG108-15 mouse neuroblastoma x rat glioma hybrid cells, and examined the role of changes in extracellular adenosine concentrations on the effects observed. 2. NG108-15 cells incubated acutely with ethanol (1-200 mM) displayed concentration-dependent increases in basal and iloprost-stimulated (300 nM; a prostanoid IP receptor agonist) cyclic AMP accumulation but a concentration-dependent decrease in forskolin-stimulated (10 microM) accumulation. 3. Cells treated chronically with ethanol (200 mM) for 48 h displayed increases over control in basal, iloprost- (0.001-10 microM) and forskolin (0.01-100 microM)-stimulated cyclic AMP formation. However, chronic ethanol did not affect [3H]-iloprost binding to cell membranes. 4. Inclusion of adenosine deaminase (ADA; 1 unit ml-1) during the incubation period to measure cyclic AMP accumulation completely abolished the increase in basal accumulation following chronic ethanol, but did not affect the increase in iloprost stimulation. On the other hand ADA partially reversed the increase in forskolin stimulation following chronic ethanol, but even in the presence of high concentrations of ADA (5 units ml-1) the forskolin stimulation remained elevated above control. 5. Cells treated chronically with the adenosine receptor agonist 5'-(N-ethylcarboxamido)-adenosine (NECA; 10 microM for 48 h) displayed a reduction in subsequent NECA- and forskolin-stimulated cyclic AMP accumulation, but iloprost stimulation was not affected. ADA included acutely during the incubation period to measure cyclic AMP accumulation abolished the reduction in forskolin but not NECA stimulation produced by the chronic NECA pretreatment. 6. We have previously noted that ethanol inhibits NG108-15 cell proliferation and alters cell morphology.To mimic this, cells were incubated in the absence of foetal calf serum for 48 h. Following this time, basal, iloprost- and forskolin-stimulated cyclic AMP formation was enhanced over that in cells grown in the presence of serum.7. These results indicate that chronic ethanol enhances cyclic AMP formation in intact NG108-15 cells by more than one mechanism: one involves increased extracellular adenosine concentrations and the other a change in the transduction system beyond the receptor, possibly involving the adenylyl cyclase enzyme. Furthermore the ethanol-induced changes in cyclic AMP accumulation may relate to alterations in NG108-15 cell growth and development.

Exposure of NG108-15 cells to 50 mM nicotinamide [an inhibitor of mono(ADP-ribosyl)transferase] for 18 hr led to an increase in membrane associated Gs alpha measured either as cholera toxin substrate or by immunoblotting with a specific antiserum. Prolonged exposure of NG108-15 cells to iloprost is followed by homologous loss of iloprost sensitivity, and heterologous loss of fluoride-dependent activation of adenylate cyclase. Nicotinamide reversed the loss of fluoride sensitivity, but failed to restore iloprost-dependent activation of adenylate cyclase. These results with nicotinamide in NG108-15 cells contrasted with those from platelets, which also exhibit heterologous desensitization of fluoride sensitivity following prolonged exposure to iloprost. Treatment of platelets with 50 mM nicotinamide for 18 hr led to an increase of 75.0 +/- 19.4% in the amount of membrane associated cholera toxin substrate. However, there was no associated increase in the abundance of Gs alpha as determined by immunoblotting. Furthermore, in platelets there was no restoration by nicotinamide of the iloprost-dependent loss of fluoride-sensitive adenylate cyclase activity. It follows that heterologous desensitization in platelets is accompanied by inactivation of Gs alpha, which is retained within the plasma membrane in its inactive state. The nicotinamide-dependent increase in the abundance of membrane associated cholera toxin substrate and immunoreactive Gs alpha in NG108-15 cells is associated with an increase of 72.0 +/- 20.3% in the levels of mRNA encoding Gs alpha. The capacity of nicotinamide to increase the abundance of membrane associated Gs alpha was reversed when the cells were cultured in the presence of 20 micrograms/mL cycloheximide. These results suggest that the ability of nicotinamide to increase the abundance of Gs alpha in NG108-15 cells is mediated by de novo protein synthesis.

Concentrations of polychlorinated biphenyls (PCBs), DDT and its metabolites (DDTs), HCH isomers (HCHs), chlordane compounds (CHLs), aldrin, dieldrin, heptachlor, heptachlor epoxide and HCB were determined in a wide variety of foodstuffs collected from different locations in Australia, Papua New Guinea and the Solomon Islands. Elevated levels of PCBs, CHLs, DDTs and dieldrin were detected in most of the foodstuffs of animal origin. Fish samples collected near the coast of Sydney recorded noticeable concentrations of PCBs, CHLs and DDTs. PCB contamination was generally prominent in samples collected in urban areas, whereas organochlorine pesticides were distributed uniformly throughout Australia. The widespread usage of CHLs was evident from the composition of its compounds in various foods while HCHs and DDTs were found to have been used sporadically in space and time. For the most part, residue levels of organochlorines in foodstuffs were below the tolerance limits established by national and international health organizations. The exception was CHLs in some fish samples, which exceeded the maximum residue limits recommended by the National Health and Medical Research Council of the Australian government. Although the number of samples analysed in each class of foods is small for the purpose of estimating human dietary exposure, we tentatively conclude that the dietary intake of PCBs in Australia was higher than those observed in most developed and developing nations, whereas the intake of organochlorine pesticides was higher than in developed nations but lower than in developing countries. Meat products contributed to the higher dietary intakes of most of the organochlorines. The contamination pattern and the residual concentrations of organochlorines in foodstuffs of Papua New Guinea and the Solomon Islands resembled those observed in Australia.

NG108-15 mouse neuroblastoma x rat glioma cells were treated with the prostanoid IP receptor agonist iloprost (1 microM) and the time course of changes in the levels of prostanoid IP receptors, adenylyl cyclase activity, and the alpha-subunit of the stimulatory guanine nucleotide binding regulatory protein, Gs, were measured. Incubation of cells with iloprost produced a biphasic time course of desensitisation of prostanoid IP receptor-activated adenylyl cyclase. Parallel analysis of iloprost-induced loss of membrane Gs alpha, NaF-stimulated adenylyl cyclase and [3H]iloprost binding suggested only monophasic curves, with t0.5 values similar to the initial phase of desensitisation of iloprost-stimulated adenylyl cyclase activity. This suggests that the loss of receptor and Gs alpha occur at the same time and account for the initial period of desensitisation due to iloprost pretreatment. Pretreatment of NG108-15 cells with cholera toxin produced a near complete loss of membrane-associated Gs alpha, but the loss of [3H]iloprost binding due to iloprost treatment was not affected by pretreatment with cholera toxin, suggesting that prostanoid IP receptors can be down-regulated in the absence of any coupling to Gs. The second phase of desensitisation of iloprost-stimulated adenylyl cyclase activity, during which there was no further change in NaF-stimulated adenylyl cyclase or in the membrane levels of Gs alpha, was not due to protein kinase A activation, since elevating intracellular cyclic AMP levels with forskolin did not subsequently decrease iloprost-stimulated adenylyl cyclase activity or [3H]iloprost binding. These results demonstrate that iloprost pretreatment of NG108-15 cells induces two distinct phases of desensitisation; an initial desensitisation due to concurrent loss of prostanoid IP receptors and Gs alpha, and then a further desensitisation by an as yet uncharacterized mechanism during which there is no further loss of Gs alpha.

A series of theoretical analyses of mortality were performed on recent data for Mediterranean fruit flies (Ceratitus capitata). Best fit computations were performed using the Marquardt-Levenburg technique on: 1) the classic Gompertz model, 2) the Johnson-Mehl-Avrami (JMA) model from chemical kinetics theory, which is formally a Weibull model, and 3) a hyperexponential gamma distribution model that we developed to help explain the relative success of the JMA model when compared with the Gompertz model. It was found that both the JMA and gamma models deviated from the data by about an order of magnitude less than the Gompertz model for the first few mean fly lifetimes. We discuss likely underlying causes for the success of these models vs. the classic model.

We present a narrow-linewidth, linearly polarized neodymium-doped fiber laser that incorporates a point-by-point Bragg grating inscribed into the core of a single-polarization all-solid photonic bandgap fiber. The Bragg grating was written within a single-polarization wavelength band of the fiber; thus, the Bragg reflection was polarized. This all-fiber laser produced 7.2 W, linearly polarized output with 25 pm FWHM and 19.6 dB polarization extinction ratio.

Juveniles of commercially important fish species congregate in shallow vegetated estuarine habitats during high tides. Considerable debate has centred on whether the significance of these habitats lies in their provision of greater feeding opportunities, or shelter from predation afforded by greater structural complexity. We tested the hypothesis that an inundated mangrove and saltmarsh wetland provided feeding opportunities for itinerant species, and that the contribution of wetland primary producers and grazing herbivores could be identified in their diet, using stable isotopes of carbon and nitrogen. Potential sources of dietary carbon included mangrove, saltmarsh, seagrass, seagrass epiphytic material and benthic organic material. Saltmarsh plants (mostly Sporobolus virginicus and Juncus kraussii) and fine benthic organic material appeared to be the primary sources of dietary carbon for the resident grazing herbivores in the wetlands, based on IsoSource mixing models. During high tide, species of itinerant fish enter the mangrove and, when inundated, the saltmarsh, and feed primarily on crab larvae and copepods. Fine benthic organic matter, seagrass epiphyte, and C3 and C4 plant materials also supplement the diet of some fish. The crab larvae therefore provide a significant source of nutrition and an important link between the intertidal wetlands and the adjacent estuarine ecosystem. The carnivorous fish Acanthopagrus australis, at the highest trophic level, hunted within or adjacent to the mangrove–saltmarsh wetland and fed on several lower-order consumers within the wetland. The present study highlights the significance of mangrove and saltmarsh wetlands as a feeding habitat for resident grazers and itinerant nekton.

The point-by-point technique of fabricating fibre-Bragg gratings using an ultrafast laser enables complete control of the position of each index modification that comprises the grating. By tailoring the local phase, amplitude and spacing of the grating's refractive index modulations it is possible to create gratings with complex transmission and reflection spectra. We report a series of grating structures that were realized by exploiting these flexibilities. Such structures include gratings with controlled bandwidth, and amplitude- and phase-modulated sampled (or superstructured) gratings. A model based on coupled-mode theory provides important insights into the manufacture of such gratings. Our approach offers a quick and easy method of producing complex, non-uniform grating structures in both fibres and other mono-mode waveguiding structures.

All-fiber lasers offer increased robustness and simplicity over other fiber laser systems. Current active Q-switching techniques for all-fiber lasers rely on electro-mechanical transducers to strain-tune an intra-cavity fiber-Bragg grating, which adds complexity and can lead to vibrational sensitivity. An all-optical technique for achieving active Q-switched operation is a more elegant approach and would maintain the inherent robustness and simplicity of an all-fiber laser system. In this work, we studied the optical tuning of a fiber-Bragg grating by resonant optical pumping and optimized it for application to active systems. We incorporated an optically-tunable fiber-Bragg grating into a fiber laser and demonstrated active Q-switching at 35 kHz with this all-optical, all-fiber laser system. We highlight the potential to operate at >300 kHz with the current embodiment. To our knowledge, this is the first demonstration of an optically-driven active Q-switch in a fiber laser. Further potential to operate at MHz frequencies is discussed.

The results of twenty-eight photogrammetric surveys published since 1982 are presented to establish that the decline of saltmarsh is a widespread trend in southeast Australian estuaries. The decline of saltmarsh is usually associated with invasion by the mangrove Avicennia marina (Forssk.) Vierh., though development pressures have also contributed to local losses.

The relationship between human sex ratios at birth and caloric availability per capita was examined across different countries. Significant positive correlations were obtained between the amount of food a country had available and the percentage of male births. Furthermore, increases or decreases in a country's caloric availability were related to corresponding changes in that country's sex ratio. These results provide evidence of adaptive sex ratio biasing in humans. The physiological mechanism by which this effect operates is probably higher mortality rates for male embryos and fetuses as a result of nutritional deficiencies and associated stressors.Researchers applied data on caloric supply per capita and on number of female and male live births to the Pearson product-moment correlation to examine the relationship between various countries' caloric supply per capita and their sex ratio at birth. In 1979-80 and 1982-84, mean caloric availability and percentage of male births had a significant positive correlation (coeff. = .365 and .524, respectively; p .01 in both periods). Further, increases or decreases in a country's caloric availability (e.g., famine) in the 2 years following a stable 3-year-period were significantly correlated to corresponding changes in that country's percentage of male births (coeff. = .524; p .01). Even thought deviations from the mean 51.33% were minimal (SD = .55%), a small deviation equalled many 1000s of excess male or female births in countries with large populations. These findings suggested that adaptive sex ratio biasing occurs in humans. The physiological mechanism responsible for this biasing may be nutritional deficiencies during gestation causing increased mortality rates for male embryos and fetuses. The variance explained by changes in caloric supply was 28%, but several confounding factors may have reduced the extent of the correlations. For example, unavailability of birth and/or caloric supply data prevented the researchers from including many of the poorest countries. In fact, the 1980 World Tables indicated that 36% of all countries had a caloric supply per capita 100% of requirements while the countries meeting this definition in the study made up just 13% of all countries. Further, countries with caloric supplies 120% of requirements made up 54% of the countries in the study. Another concern was that food availability does not necessarily mean equal distribution or consumption of the food.

Fiber Bragg gratings inscribed with a femtosecond laser using the point-by-point (PbP) technique have polarization dependent grating strength (PDGS) and exhibit birefringence. In this paper we quantify the dependence of these two properties on the ellipticity, position in the core and size of the micro-voids at the center of each refractive index modulation. We demonstrate that the effective modal index for type II gratings written with a femtosecond laser using the PbP method must be lower than that of the pristine fiber, and for the first time associate an axis with a polarization such that the long axis of the elliptically-shaped index modulations corresponds to the slow axis of the gratings. We exploit the PDGS of two gratings used as frequency-selective feedback elements as well as appropriate coiling, to realize a linearly-polarized fiber laser with a low birefringence fiber cavity. We show that the polarization-dependent grating strength is a function of the writing pulse energy and that only gratings optimized for this property will linearly polarize the fiber laser. The fiber lasers have high extinction ratios (>30 dB) for fiber lengths of up to 10 m and very stable polarized output powers (

Current levels of self-reported drinking amongst young adults predicted scores on measures of both positive expectancies for alcohol use and negative alcohol effects (symptoms of dependence). No overall sex difference was shown in the main effects, but there was a significant interaction effect between sex and alcohol consumption on the dependency and expectancy scales. The form of this interaction was different for expectancy and dependency scores. There was a cross-over effect in the case of expectancy: light drinking females revealed lower levels of expectancy than did light drinking males whereas heavier drinking females reported higher levels of expectancy than did males at a comparable level of consumption. There was a higher proportion of heavy female drinkers in this sample than is usually reported. With regard to dependence, the trend in sex differences was divergent: whereas males acknowledged increases in symptoms concomitant with increases in consumption, comparable female drinkers reported relatively little increase in such symptoms. Results were discussed in terms of quantity-related concepts of 'utility' of alcohol use and a 'diminished personal harm' rationalization associated with the negative effects of alcohol.

We have shown previously that partially purified human chorionic gonadotrophin (hCG) preparations inhibited the specific binding of I-labelled hLH or hCG to Candida albicans membranes at much lower concentrations than did highly purified hLH or hCG preparations. We now describe the characterization and partial purification of a heat-labile glycoprotein from commercially available gonadotrophin preparations. The factor strongly inhibited LH binding to Candida membranes, but not to sheep or pig luteal LH receptors. This material had a molecular weight of 16 000–21 000 daltons, bound strongly to CM-Sepharose at physiological pH, and could be resolved completely from hCG and from epidermal growth factor-like factors present in commercial gonadotrophin preparations. Its activity was not attenuated by a range of inhibitors specific for the four major classes of proteolytic enzymes, nor did it inhibit hormone binding by causing degradation of 125 I-labelled hLH or hCG tracers. Factors which inhibited hLH binding to Candida membranes were also present in partially purified human urinary and equine serum gonadotrophin preparations and in placental extracts, but were not detected in highly purified CG of hLH preparations. The properties of this factor were similar to those described for β-core protein, a cleavage product of the β subunit of hCG which is a contaminant of commercial gonadotrophin preparations. Highly purified β-core protein inhibited 125I-labelled hLH binding to Candida membranes, but not to sheep luteal binding sites. Preparations of hCG depleted of inhibitor activity could stimulate adenylate cyclase activity in Candida membranes almost five fold. In contrast, partially purified inhibitor preparations strongly inhibited basal adenylate cyclase activity (to 18% of control levels). These observations suggest that endogenous LH-like factors, perhaps similar to β-core proteins of hCG, may play a role in the regulation of morphogenesis in Candida species. Journal of Endocrinology (1991) 128, 139–151

The presence of specific binding sites for [125I]-labelled hLH and hCG is described in Candida species. Binding was present in three strains of Candida albicans, and in Candida tropicalis, and was greatest in microsomes, though binding was also present in cytosol fractions. hLH and hCG mutually competed for these binding sites. Other hormones did not bind and did not compete for hLH binding sites. Scatchard plots showed two classes of binding sites, one with high affinity, low capacity and the other with lower affinity, high capacity binding in both microsomes and cytosol. This is the first report of specific binding sites for mammalian peptide hormones in a yeast.

The selection of appropriate sampling methods is a prerequisite for the design of any survey detailing nekton assemblages. In the present study two commonly used saltmarsh fish sampling methods, the fyke net and the buoyant pop net, were used to compare the assemblages of fish caught in a saltmarsh flat during monthly spring tides over a twelve month period. Both nets were made of 2mm mesh. A total of 3514 fish and crustaceans of 21 species were captured by 48 fyke net sets and 818 fish of 16 species were captured by 48 pop net releases. Fyke and pop nets recorded significantly different (ANOSIM: P