Oxidative stress-related lung dysfunction by chromium(VI): alleviation by Citrus aurantium L.

Chromium(VI), a very strong oxidant, causes high cytotoxicity through oxidative stress in tissue systems. Our study investigated the potential ability of ethanolic Citrus aurantium L., family Rutaceae extract, used as a nutritional supplement, to alleviate lung oxidative damage induced by Cr(VI). A high-performance liquid chromatography coupled with a mass spectrometer method was developed to separate and identify flavonoids in C. aurantium L. Six flavonoids were identified, as (1) poncirin, (2) naringin, (3) naringenin, (4) quercetin, (5) isosinensetin, and (6) tetramethyl-o-isoscutellarein. Adult Wistar rats, used in this study, were divided into six groups of six animals each: group I served as controls which received standard diet, group II received via drinking water K₂Cr₂O₇ alone (700 ppm), groups III and IV were pretreated for 10 days with ethanol extract of C. aurantium L. at doses of 100 and 300 mg/kg body weight/day, respectively, and then K₂Cr₂O₇ was administrated during 3 weeks, and groups V and VI received during 10 days only C. aurantium L. ethanol extract at doses of 100 and 300 mg/kg/day, respectively. Ethanol extract of C. aurantium L. was administered orally. Rats exposed to Cr(VI) showed in lung an increase in malondialdehyde and protein carbonyl levels and a decrease in sulflydryl content, glutathione, nonprotein thiol, and vitamins C and E levels. Decreases in enzyme activities such as in Na⁺K⁺ ATPase, catalase, glutathione peroxidase, and superoxide dismutase were noted. Pretreatment with C. aurantium L. of chromium-treated rats ameliorated all biochemical parameters. Lung histological studies confirmed the biochemical parameters and the beneficial role of C. aurantium L.     

The lack of CB1 receptors prevents neuroadapatations of both NMDA and GABA(A) receptors after chronic ethanol exposure

As the contribution of cannabinoid (CB1) receptors in the neuroadaptations following chronic alcohol exposure is unknown, we investigated the neuroadaptations induced by chronic alcohol exposure on both NMDA and GABA(A) receptors in CB1-/- mice. Our results show that basal levels of hippocampal [(3)H]MK-801 ((1)-5-methyl-10,11-dihydro-5Hdibenzo[a,d]cyclohepten-5,10-imine) binding sites were decreased in CB1-/- mice and that these mice were also less sensitive to the locomotor effects of MK-801. Basal level of both hippocampal and cerebellar [(3)H]muscimol binding was lower and sensitivity to the hypothermic effects of diazepam and pentobarbital was increased in CB1-/- mice. GABA(A)alpha1, beta2, and gamma2 and NMDA receptor (NR) 1 and 2B subunit mRNA levels were altered in striatum of CB1-/- mice. Our results also showed that [(3)H]MK-801 binding sites were increased in cerebral cortex and hippocampus after chronic ethanol ingestion only in wild-type mice. Chronic ethanol ingestion did not modify the sensitivity to the locomotor effects of MK-801 in both genotypes. Similarly, chronic ethanol ingestion reduced the number of [(3)H]muscimol binding sites in cerebral cortex, but not in cerebellum, only in CB1+/+ mice. We conclude that lifelong deletion of CB1 receptors impairs neuroadaptations of both NMDA and GABA(A) receptors after chronic ethanol exposure and that the endocannabinoid/CB1 receptor system is involved in alcohol dependence.     

Abrogation of hybrid resistance to bone marrow engraftment by graft-vs-host-induced immune deficiency

Lethally irradiated F1 mice, heterozygous at the hematopoietic histocompatibility locus Hh-1, which is linked with H-2Db, reject bone marrow grafts from H-2b parents. This hybrid resistance (HR) is reduced by prior injection of H-2b parental spleen cells. Because injection of parental spleen cells produces a profound suppression of F1 immune functions, we investigated whether parental-induced abrogation of HR was due to graft-vs-host-induced immune deficiency (GVHID). HR was assessed by quantifying engraftment of H-2b bone marrow in F1 mice with the use of splenic [125I]IUdR uptake; GVHID, by the ability of F1 spleen cells to generate cytotoxic T lymphocytes (CTL) in vitro. We observed a correlation in the time course and spleen cell dose dependence between loss of HR and GVHID. Both GVHID and loss of HR were dependent on injection of parental T cells; nude or T-depleted spleen cells were ineffective. The injection of B10 recombinant congenic spleens into (B10 X B10.A)F1 mice, before grafting with B10 marrow, demonstrated that only those disparities in major histocompatibility antigens that generated GVH would result in loss of HR. Thus, spleens from (B10 X B10.A(2R]F1 mice (Class I disparity only) did not induce GVHID or affect HR, whereas (B10 X B10.A(5R))F1 spleens (Class I and II disparity) abrogated CTL generation and HR completely. GVHID produced by a class II only disparity, as in (B10 X B10.A(5R))F1 spleens injected into (B6bm12 X B10.A(5R))F1 mice, was also sufficient to markedly reduce HR to B10 bone marrow. This evidence that GVHID can modulate hematopoietic graft rejection may be relevant to the mechanisms of natural resistance to marrow grafts in man.     

Regulation of plasma membrane Ca2+ ATPases by lipids of the phosphatidylinositol cycle

When the erythrocyte plasma membrane Ca2+ pump is reconstituted into phosphatidylcholine liposomes, the inclusion of small amounts of phosphatidic acid or phosphatidylinositol 4,5-bisphosphate stimulates the enzyme's activity. Other lipids of the phosphatidylinositol cycle (diacylglycerol, phosphatidylinositol) have little effect. The stimulatory effect of phosphatidylinositol 4,5-bisphosphate is greater than that of calmodulin; this lipid also stimulates the plasma membrane Ca2+ ATPase from rat brain.     

Altitudinal variation in phase response curves for the Himalayan strains of Drosophila helvetica

In previous research, it was determined that the altitude of origin altered the parameters of photic entrainment and free-running rhythmicity of adult locomotor activity of the high-altitude Himalayan (haH) strain (Hemkund-Sahib, 4121 m above sea level) of Drosophila helvetica compared to the low-altitude Himalayan (laH) strain (Birahi, 1132 m above sea level) of the same species. The present study investigated whether the altitude of origin also affects the parameters of the light pulse phase response curve (PRC) of the adult locomotor activity rhythm of the haH strain. Light pulse PRCs were determined for both strains against the background of constant darkness. Although both were "weak" or type 1 PRCs, the PRC for the haH strain differed from that of the laH strain in three basic parameters. The PRC for the haH strain was of low amplitude, had a protracted dead zone, and showed a ratio of the advance to delay region (A/D>1), while the PRC of the laH strain was characterized by high amplitude, absence of dead zone, and a A/D ratio<1. The asymmetric PRCs of these strains might explain the process of photic entrainment to 24 h light-dark cycles, as the long period of the free-running rhythm (tau) of the haH strain is complemented with a larger advance portion of its PRC (A/D>1), whereas the short tau of the laH strain is matched with a larger delay portion of its PRC (A/D<1). Prolonged dead zone and low amplitude in the PRC of the haH strain imply that the photic sensitivity of this strain has been drastically diminished as an adaptation to environmental conditions at the altitude of its origin. While adults of this strain begin activity in very bright light in the forenoon due to non-permissible low temperature in the morning, the converse is true for the laH strain.     

Effect of sulfite treatment on total antioxidant capacity, total oxidant status, lipid hydroperoxide, and total free sulfydryl groups contents in normal and sulfite oxidase-deficient rat plasma

Sulfites, which are commonly used as preservatives, are continuously formed in the body during the metabolism of sulfur-containing amino acids. Sulfite oxidase (SOX) is an essential enzyme in the pathway of the oxidative degradation of sulfite to sulfate protecting cells from sulfite toxicity. This article investigated the effect of sulfite on total antioxidant capacity (TAC), total oxidant status, lipid hydroperoxide (LOOH), and total free sulfydryl groups (-SH) levels in normal and SOX-deficient male albino rat plasma. For this purpose, rats were divided into four groups: control, sulfite-treated, SOX-deficient, and sulfite-treated SOX-deficient groups. SOX deficiency was established by feeding rats a low molybdenum diet and adding to their drinking water 200 ppm tungsten. Sulfite (70 mg/kg) was administered to the animals via their drinking water. SOX deficiency together with sulfite treatment caused a significant increase in the plasma LOOH and total oxidant status levels. -SH content of rat plasma significantly decreased by both sulfite treatment and SOX deficiency compared to the control. There was also a significant decrease in plasma TAC level by sulfite treatment. In conclusion, sulfite treatment affects the antioxidant/oxidant balance of the plasma cells of the rats toward oxidants in SOX-deficient groups.     

Growth and differentiation of the larval midgut epithelium during molting in the moth, Manduca sexta

The number of epithelial cells comprising larval midgut of the tobacco hornworm moth, Manduca sexta increases 200-fold in development from the first to the fifth instar. We have examined larvae periodically before and during molting to follow epithelial cell proliferation and differentiation. The midgut epithelium in Manduca sexta consists predominantly of columnar and goblet cells. These are arranged in a characteristic pattern with each goblet cell surrounded by a single layer of 4-6 columnar cells (Hakim et al., (1988)). While undifferentiated basal stem cells are infrequently seen in intermolt larvae, just prior to the period when external signs of molting are visible, their number increases and mitotic figures become common. Proliferation continues for several hours and then these stem cells differentiate following a pattern similar to that seen during embryogenesis (Hakim et al., (1988)). Here, however, the newly differentiating cells become intercalated among the mature differentiated cells already present in the epithelium. Since the pattern of individual goblet cells surrounded by a reticulum of columnar cells is maintained after the addition of new cells, the midgut epithelium of molting larvae appears to be a useful model for studying pattern formation in development.     

What factors account for black–white differences in anti-Muslim sentiment in the contemporary USA?

I use data from the 2004 General Social Survey (N=719) and multivariate analyses to: explore the effects of race on attitudes toward Muslims; evaluate the extent to which the racial differences were mediated by psychological and religious factors; and assess whether the race effects differed significantly by gender. The findings show that blacks report significantly more favourable feelings toward Muslims than whites. Those respondents who are female, more educated and Catholic also hold significantly higher scores on the 100-point scale assessing feelings toward Muslims. After controlling for religious and psychological factors, I find that the racial difference in feelings toward Muslims is increased, indicating that the race effect is suppressed by these factors. Moderation analysis reveals that white men hold the highest level of negative feelings toward Muslims, compared to women and black men. The findings suggest challenging the misconstrued perceptions of Muslims through education and endorsement of positive images.     

Enhanced activity of hyperthermostable Pyrococcus horikoshii endoglucanase in superbase ionic liquids

Biotechnology Letters - Ionic liquids (ILs) that dissolve biomass are harmful to the enzymes that degrade lignocellulose. Enzyme hyperthermostability promotes a tolerance to ILs. Therefore, the...