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Endogenous Levels (endogenous + level)
Selected AbstractsCandesartan pretreatment is cerebroprotective in a rat model of endothelin-1-induced middle cerebral artery occlusionEXPERIMENTAL PHYSIOLOGY, Issue 8 2009Adam P. Mecca Endogenous levels of angiotensin II (Ang II) are increased in the cortex and hypothalamus following stroke, and Ang II type 1 receptor blockers (ARBs) have been shown to attenuate the deleterious effects in animal stroke models using middle cerebral artery (MCA) intraluminal occlusion procedures. However, the endothelin-1 (ET-1)-induced middle cerebral artery occlusion (MCAO) model of cerebral ischaemia is thought to more closely mimic the temporal events of an embolic stroke. This method provides rapid occlusion of the MCA and a gradual reperfusion that lasts for 16,22 h. The aim of the present study was to evaluate whether systemic administration of an ARB prior to ET-1-induced MCAO would provide cerebroprotection during this model of ischaemic stroke. Injection of 3 ,l of 80 ,m ET-1 adjacent to the MCA resulted in complete occlusion of the vessel that resolved over a period of 30,40 min. Following ET-1-induced MCAO, rats had significant neurological impairment, as well as an infarct that consisted of 30% of the ipsilateral grey matter. Systemic pretreatment with 0.2 mg kg,1 day,1 candesartan for 7 days attenuated both the infarct size and the neurological deficits caused by ET-1-induced MCAO without altering blood pressure. This study confirms the cerebroprotective properties of ARBs during ischaemic stroke and validates the ET-1-induced MCAO model for examination of the role of the brain renin,angiotensin system in ischaemic stroke. [source] Evaluation of a magnetic resonance biomarker of osteoarthritis disease progression: doxycycline slows tibial cartilage loss in the Dunkin Hartley guinea pigINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 2 2009Jonathan Bowyer Summary The objective was to assess the effect of doxycycline treatment on a magnetic resonance imaging (MRI) biomarker of cartilage volume loss, and on matrix metalloproteinase (MMP) activity in a guinea pig osteoarthritis model. Guinea pigs (9 months old) were dosed with vehicle or doxycycline, 0.6, 3.0 mg/kg/day for 66 days. Fat-suppressed 3D gradient-echo MRI of the left knee was acquired pre- and post dosing. Change in medial tibial plateau (MTP) cartilage volume (MT.VC) was determined using image analysis. At termination, MTP cartilage was removed from knees and proteolytic MMP activity determined using a fluorescent peptide substrate assay. Vehicle-treated animals lost 20.5% (95% CI mean 25.6,15.1) MT.VC. The doxycycline (0.6 mg/kg/day) group lost 8.6% (P < 0.05, 95% CI 20.6 to ,5.3) whilst the 3.0 mg/kg/day group lost 10.0% (P < 0.05, 95% CI 13.9,6.0%). Endogenous levels of active MMPs were below limits of detection in all samples. However, doxycycline treatment ablated amino phenyl mercuric acid activated MMP-13 and MMP-8 levels, reduced MMP-9 levels by 65% and MMP-1 levels by 24%. Doxycycline treatment resulted in partial protection from MT.VC loss and was associated with complete reduction in MMP-13 and MMP-8, and partial reduction in MMP-9 activity. These data imply a role of MMPs in cartilage degeneration but incomplete protection suggests that additional doxycycline insensitive mechanisms are important in this model. The protective effect of doxycycline correlates with the clinical finding of lessened joint space narrowing, strengthens the utility of this animal model in identifying disease-modifying osteoarthritic drugs and supports the use of MRI biomarkers of cartilage loss. [source] Systemic Potato virus YNTN infection and levels of salicylic and gentisic acids in different potato genotypesPLANT PATHOLOGY, Issue 4 2005-Stres, H. Kre Endogenous levels of free and conjugated salicylic (SA) and gentisic (GA) acids, both putative signal molecules in plant defence, were analysed in order to investigate their involvement in the resistance of four potato (Solanum tuberosum) genotypes with different susceptibilities to Potato virus YNTN (PVYNTN) infection: the highly susceptible cv. Igor and its extremely resistant transgenic line, the extremely resistant cv. Sante and the tolerant cv. Pentland Squire. The lowest levels of free and conjugated SA were observed in the extremely resistant cv. Sante, while free GA, which was detected in all the other varieties, was absent. The extremely resistant transgenic cv. Igor contained the highest basal total SA level and the lowest level of total GA of all four cultivars. In susceptible cv. Igor, but not in resistant transgenic cv. Igor, a systemic increase of free SA was measured 1 day postinfection (dpi). Even more significant increases of free and conjugated SA and GA were detected 11 dpi when systemic symptoms appeared. In inoculated but not in upper noninoculated leaves of resistant transgenic cv. Igor, significant increase of SA conjugates occurred, but not before 11 dpi. The increase of SA and GA in susceptible cv. Igor could contribute to the general elevated levels of phenolic compounds as a response to stress caused by virus infection. It appears that basal levels of SA and GA do not correlate with resistance to PVYNTN in potato plants. [source] Retinoic acid is a negative physiological regulator of N-cadherin during early avian heart morphogenesisDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 9 2009Mahmoud Romeih The vitamin A-deficient (VAD) early avian embryo has a grossly abnormal cardiovascular system that is rescued by treating the embryo with the vitamin A-active form, retinoic acid (RA). Here we examine the role of N-cadherin (N-cad) in RA-regulated early cardiovascular morphogenesis. N-cad mRNA and protein are expressed globally in the presomite through HH14 normal and VAD quail embryos. The expression in VAD embryos prior to HH10 is significantly higher than that in normal embryos. Functional analyses of the N-cad overproducing VAD embryos reveal N-cad involvement in the RA-regulated cardiovascular development and suggest that N-cad expression may be mediated by Msx1. We provide evidence that in the early avian embryo, endogenous RA is a negative physiological regulator of N-cad. We hypothesize that a critical endogenous level of N-cad is needed for normal early cardiovascular morphogenesis to occur and that this level is ensured by stage-specific, developmentally regulated RA signaling. [source] The role of insulin-like growth factor-I and its binding proteins in glucose homeostasis and type 2 diabetesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 1 2009Swapnil N. Rajpathak Abstract This review addresses the possible role of the insulin-like growth factor (IGF)-axis in normal glucose homoeostasis and in the etiopathogenesis of type 2 diabetes. IGF-I, a peptide hormone, shares amino acid sequence homology with insulin and has insulin-like activity; most notably, the promotion of glucose uptake by peripheral tissues. Type 2 diabetes as well as pre-diabetic states, including impaired fasting glucose and impaired glucose tolerance, are associated cross-sectionally with altered circulating levels of IGF-I and its binding proteins (IGFBPs). Administration of recombinant human IGF-I has been reported to improve insulin sensitivity in healthy individuals as well as in patients with insulin resistance and type 2 diabetes. Further, IGF-I may have beneficial effects on systemic inflammation, a risk factor for type 2 diabetes, and on pancreatic ,-cell mass and function. There is considerable inter-individual heterogeneity in endogenous levels of IGF-I and its binding proteins; however, the relationship between these variations and the risk of developing type 2 diabetes has not been extensively investigated. Large prospective studies are required to evaluate this association. Copyright © 2009 John Wiley & Sons, Ltd. [source] An efficient protein preparation for proteomic analysis of developing cotton fibers by 2-DEELECTROPHORESIS, Issue 22 2006Yuan Yao Abstract Preparation of high-quality proteins from cotton fiber tissues is difficult due to high endogenous levels of polysaccharides, polyphenols, and other interfering compounds. To establish a routine procedure for the application of proteomic analysis to cotton fiber tissues, a new protocol for protein extraction was developed by optimizing a phenol extraction method combined with methanol/ammonium acetate precipitation. The protein extraction for 2-DE was remarkably improved by the combination of chemically and physically modified processes including polyvinylpolypyrrolidone (PVPP) addition, acetone cleaning, and SDS replacement. The protocol gave a higher protein yield and vastly greater resolution and spot intensity. The efficiency of this protocol and its feasibility in fiber proteomic study were demonstrated by comparison of the cotton fiber proteomes at two growth stages. Furthermore, ten protein spots changed significantly were identified by MS/tandem MS and their potential relationships to fiber development were discussed. To the best of our knowledge, this is the first time that a protocol for protein extraction from cotton fiber tissues appears to give satisfactory and reproductive 2-D protein profiles. The protocol is expected to accelerate the process of the proteomic study of cotton fibers and also to be applicable to other recalcitrant plant tissues. [source] Synergistic interaction of endocrine-disrupting chemicals: Model development using an ecdysone receptor antagonist and a hormone synthesis inhibitorENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2004Xueyan Mu Abstract Endocrine toxicants can interfere with hormone signaling through various mechanisms. Some of these mechanisms are interrelated in a manner that might result in synergistic interactions. Here we tested the hypothesis that combined exposure to chemicals that inhibit hormone synthesis and that function as hormone receptor antagonists would result in greater-than-additive toxicity. This hypothesis was tested by assessing the effects of the ecdysteroid-synthesis inhibitor fenarimol and the ecdysteroid receptor antagonist testosterone on ecdysteroid-regulated development in the crustacean Daphnia magna. Both compounds were individually characterized for effects on the development of isolated embryos. Fenarimol caused late developmental abnormalities, consistent with its effect on offspring-derived ecdysone in the maturing embryo. Testosterone interfered with both early and late development of embryos, consistent with its ability to inhibit ecdysone provided by maternal transfer (responsible for early developmental events) or de novo ecdysone synthesis (responsible for late developmental events). We predicted that, by decreasing endogenous levels of hormone, fenarimol would enhance the likelihood of testosterone binding to and inhibiting the ecdysone receptor. Indeed, fenarimol enhanced the toxicity of testosterone, while testosterone had no effect on the toxicity of fenarimol. Algorithms were developed to predict the toxicity of combinations of these two compounds based on independent joint action (IJA) alone as well as IJA with fenarimol-on-testosterone synergy (IJA+SYN). The IJA+SYN model was highly predictive of the experimentally determined combined effects of the two compounds. These results demonstrate that some endocrine toxicants can synergize, and this synergy can be accurately predicted. [source] Resetting the brain clock: time course and localization of mPER1 and mPER2 protein expression in suprachiasmatic nuclei during phase shiftsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2004Lily Yan Abstract The mechanism whereby brief light pulses reset the mammalian circadian clock involves acute Per gene induction. In a previous study we investigated light-induced expression of mPer1 and mPer2 mRNA in the suprachiasmatic nuclei (SCN), with the aim of understanding the relationship between gene expression and behavioural phase shifts. In the present study, we examine the protein products of mPer1 and mPer2 genes in the core and shell region of SCN for 34 h following a phase-shifting light pulse, in order to further explore the molecular mechanism of photic entrainment. The results indicate that, during the delay zone of the phase response curve, while endogenous levels of mPER1 and mPER2 protein are falling, a light pulse produces an increase in the expression of both proteins. In contrast, during the advance zone of the phase response curve, while levels of endogenous mPER1 and mPER2 proteins are rising, a light pulse results in a further increase in mPER1 but not mPER2 protein. The regional distribution of mPER1 and mPER2 protein in the SCN follows the same pattern as their respective mRNAs, with mPER1 expression in the shell region of SCN correlated with phase advances and mPER2 in the shell region correlated with phase delays. [source] Regulation of GluR2 promoter activity by neurotrophic factors via a neuron-restrictive silencer elementEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2000Stefan Brené Abstract The AMPA glutamate receptor subunit GluR2, which plays a critical role in regulation of AMPA channel function, shows altered levels of expression in vivo after several chronic perturbations. To evaluate the possibility that transcriptional mechanisms are involved, we studied a 1254-nucleotide fragment of the 5,-promoter region of the mouse GluR2 gene in neural-derived cell lines. We focused on regulation of GluR2 promoter activity by two neurotrophic factors, which are known to be altered in vivo in some of the same systems that show GluR2 regulation. Glial-cell line derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) both induced GluR2 promoter activity. This was associated with increased expression of endogenous GluR2 immunoreactivity in the cells as measured by Western blotting. The effect of GDNF and BDNF appeared to be mediated via a NRSE (neuron-restrictive silencer element) present within the GluR2 promoter. The response to these neurotrophic factors was lost upon mutating or deleting this site, but not several other putative response elements present within the promoter. Moreover, overexpression of REST (restrictive element silencer transcription factor; also referred to as NRSF or neuron restrictive silencer factor), which is known to act on NRSEs in other genes to repress gene expression, blocked the ability of GDNF to induce GluR2 promoter activity. However, GDNF did not alter endogenous levels of REST in the cells. Together, these findings suggest that GluR2 expression can be regulated by neurotrophic factors via an apparently novel mechanism involving the NRSE present within the GluR2 gene promoter. [source] The effect of exogenous pectinase on DMHF and derivatives in clarified strawberry juice (Fragaria × ananassa, cv. Elsanta)FLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2002Emanuela Mura Abstract The effect of exogenous pectinase on the levels of 2,5-dimethyl-4-hydroxy-2H -furan-one (DMHF) and DMHF-glucoside was studied in clarified strawberry juice (Fragaria × ananassa, cv. Elsanta). The extent of conversion of DMHF-malonyl glucoside to DMHF-glucoside and DMHF was monitored at three different temperatures (45 °C, 50 °C and 60 °C) and at three different pH values (pH 3.0, 4.0 and 5.4). The effect of using two different concentrations of pectinase was also studied. Based on these results, the endogenous levels of DMHF-malonyl glucoside were calculated for the first time in strawberries. Copyright © 2002 John Wiley & Sons, Ltd. [source] Testosterone and innate immune function inversely covary in a wild population of breeding Dark-Eyed Juncos (Junco hyemalis)FUNCTIONAL ECOLOGY, Issue 5 2006T. J. GREIVES Summary 1Innate immunity refers to the non-specific components of the primary immune response, which act broadly to destroy pathogens. Effective innate immune responses may save an individual the energetic costs associated with activating subsequent specific immune responses. 2Testosterone can suppress immune function in vitro and in vivo. Most studies examining testosterone's effects on immunity have focused on experimentally elevated testosterone and acquired immune responses (e.g. humoral and cell-mediated responses to foreign antigens). Few studies have investigated the relationship between endogenous levels of testosterone and innate immunity. 3In a wild breeding population of Dark-Eyed Juncos (Junco hyemalis Linnaeus), we asked whether endogenous levels of testosterone measured at several points during the breeding season covaried with two components of innate immunity: total levels of non-specific immunoglobulin-G (IgG), and complement levels. 4Testosterone levels were significantly negatively correlated with both total IgG and complement activity. Both immune measures were also positively correlated with body mass. Taken together with experimental results from the same species, these results suggest that elevated testosterone levels may compromise innate as well as acquired immune function. [source] Endogenous DNA damage and testicular germ cell tumorsINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 6 2009M. B. Cook Summary Testicular germ cell tumors are comprised of two histologic groups, seminomas and non-seminomas. We postulated that the possible divergent pathogeneses of these histologies may be partially explained by variable levels of net endogenous DNA damage. To test our hypothesis, we conducted a case,case analysis of 51 seminoma and 61 non-seminoma patients using data and specimens from the Familial Testicular Cancer study and the U.S. Radiologic Technologists cohort. A lymphoblastoid cell line was cultured for each patient and the alkaline comet assay was used to determine four parameters: tail DNA, tail length, comet distributed moment (CDM) and Olive tail moment (OTM). Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using logistic regression. Values for tail length, tail DNA, CDM and OTM were modelled as categorical variables using the 50th and 75th percentiles of the seminoma group. Tail DNA was significantly associated with non-seminoma compared with seminoma (OR50th percentile = 3.31, 95% CI: 1.00, 10.98; OR75th percentile = 3.71, 95% CI: 1.04, 13.20; p for trend = 0.039). OTM exhibited similar, albeit statistically non-significant, risk estimates (OR50th percentile = 2.27, 95% CI: 0.75, 6.87; OR75th percentile = 2.40, 95% CI: 0.75, 7.71; p for trend = 0.12) whereas tail length and CDM showed no association. In conclusion, the results for tail DNA and OTM indicate that net endogenous levels are higher in patients who develop non-seminoma compared with seminoma. This may partly explain the more aggressive biology and younger age-of-onset of this histologic subgroup compared with the relatively less aggressive, later-onset seminoma. [source] The ,oestrogen hypothesis', where do we stand now?,INTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2003Richard M. Sharpe Summary The original ,oestrogen hypothesis' postulated that the apparent increase in human male reproductive developmental disorders (testis cancer, cryptorchidism, hypospadias, low sperm counts) might have occurred because of increased oestrogen exposure of the human foetus/neonate; five potential routes of exposure were considered. This review revisits this hypothesis in the light of the data to have emerged since 1993. It addresses whether there is a secular increasing trend in the listed disorders and highlights the limitations of available data and how these are being addressed. It considers whether new data has emerged to support the suggestion that increased oestrogen exposure could cause these abnormalities and reviews new data on potential routes via which such increased exposure could have occurred. Secular trends: The disorders listed above are now considered to represent a syndrome of disorders (testicular dysgenesis syndrome, TDS) with a common origin in foetal life. Testicular cancer has increased in incidence in Caucasian men worldwide and lifetime risk is 0.3,0.8%. Secular trends in cryptorchidism are unclear but it is by far the commonest (2,4% at birth) congenital abnormality in either sex. Secular trends for hypospadias are not robust, although most studies suggest a progressive increase; registry data probably under-estimates incidence, but based on this data hypospadias is the second most common (0.3,0.7% at birth) congenital malformation. Retrospective analyses of sperm count data show a global downward trend but this is inconclusive , prospective studies using standardized methodology show significant differences between countries and very low sperm counts in the youngest cohort of men. For all disorders, other then testis cancer, standardized prospective studies are the best way forward and are in progress across Europe. Oestrogen effects: Evidence that foetal exposure to oestrogens can induce the above disorders has strengthened. New pathways via which such changes could be induced have been identified, including suppression of testosterone production by the foetal testis, suppression of androgen receptor expression and suppression of insulin-like factor-3 (InsL3) production by foetal Leydig cells. Other evidence suggests that the balance between androgen and oestrogen action may be important in induction of reproductive tract abnormalities. Oestrogen exposure: Although many new environmental oestrogens have been identified, their uniformly weak oestrogenicity excludes the possibility that they could induce the above disorders. However, emerging data implicates various environmental chemicals in being able to alter endogenous levels of androgens (certain phthalates) and oestrogens (polychlorinated biphenyls, polyhalogenated hydrocarbons), and the former have been shown to induce a similar collection of disorders to TDS. Other mechanisms via which increased fetal exposure to pregnancy oestrogens might occur (increasing trend in obesity, dietary changes) are also discussed. [source] Transcriptional activation of human mu-opioid receptor gene by insulin-like growth factor-I in neuronal cells is modulated by the transcription factor RESTJOURNAL OF NEUROCHEMISTRY, Issue 6 2008Andrea Bedini Abstract The human mu-opioid receptor gene (OPRM1) promoter contains a DNA sequence binding the repressor element 1 silencing transcription factor (REST) that is implicated in transcriptional repression. We investigated whether insulin-like growth factor I (IGF-I), which affects various aspects of neuronal induction and maturation, regulates OPRM1 transcription in neuronal cells in the context of the potential influence of REST. A series of OPRM1-luciferase promoter/reporter constructs were transfected into two neuronal cell models, neuroblastoma-derived SH-SY5Y cells and PC12 cells. In the former, endogenous levels of human mu-opioid receptor (hMOPr) mRNA were evaluated by real-time PCR. IGF-I up-regulated OPRM1 transcription in: PC12 cells lacking REST, in SH-SY5Y cells transfected with constructs deficient in the REST DNA binding element, or when REST was down-regulated in retinoic acid-differentiated cells. IGF-I activates the signal transducer and activator of transcription-3 signaling pathway and this transcription factor, binding to the signal transducer and activator of transcription-1/3 DNA element located in the promoter, increases OPRM1 transcription. We propose that a reduction in REST is a critical switch enabling IGF-I to up-regulate hMOPr. These findings help clarify how hMOPr expression is regulated in neuronal cells. [source] Altered Mesencephalic Dopaminergic Populations in Adulthood as a Consequence of Brief Perinatal Glucocorticoid ExposureJOURNAL OF NEUROENDOCRINOLOGY, Issue 8 2005S. McArthur Abstract Early exposure to stressors is strongly associated with enduring effects on central nervous system function, but the mechanisms and neural substrates involved in this biological ,programming' are unclear. This study tested the hypothesis that inappropriate exposure to glucocorticoid stress hormones (GCs) during critical periods of development permanently alters the mesencephalic dopaminergic populations in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). Using a rat model, the synthetic GC dexamethasone was added to the maternal drinking water during gestational days 16,19 or over the first week of postnatal life. In adulthood, the effects upon tyrosine hydroxylase immunopositive (TH+) cell numbers in the midbrain, and monoamine levels in the forebrain, of the adult offspring were assessed and compared with control offspring whose dams received normal drinking water. In the VTA, both prenatal and postnatal dexamethasone treatment increased TH+ cell numbers by approximately 50% in males and females. Although prenatal dexamethasone treatment also increased TH+ cell numbers in the SNc by 40,50% in males and females, postnatal treatment affected females only by increasing TH+ cell numbers by approximately 30%. In comparison, similar changes were not detected in the monoamine levels of the dorsolateral striatum, nucleus accumbens or infralimbic cortex of either males or females, which is a feature likely to reflect adaptive changes in these pathways. These studies demonstrate that the survival or phenotypic expression of VTA and SNc dopaminergic neurones is profoundly influenced by brief perinatal exposure to GCs at times when endogenous levels are normally low. These findings are the first to demonstrate permanent changes in the cytoarchitecture within midbrain dopamine nuclei after perinatal exposure to stress hormones and implicate altered functionality. Thus, they have significance for the increasing use of GCs in perinatal medicine and indicate potential mechanisms whereby perinatal distress may predispose to the development of a range of psychiatric conditions in later life. [source] Targeting nitric oxide for cancer therapyJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2007David Hirst A blueprint for the ideal anticancer molecule would include most of the properties of nitric oxide (NO,), but the ability to exploit these characteristics in a therapeutic setting requires a detailed understanding of the biology and biochemistry of the molecule. These properties include the ability of NO, to affect tumour angiogenesis, metastasis, blood flow and immuno surveillance. Furthermore NO, also has the potential to enhance both radio- and chemotherapy. However, all of these strategies are dependent on achieving appropriate levels of NO,, since endogenous levels of NO, appear to have a clear role in tumour progression. This review aims to summarize the role of NO, in cancer with particular emphasis on how the properties of NO, can be exploited for therapy. [source] Phenols in spikelets and leaves of field-grown oats (Avena sativa) with different inherent resistance to crown rust (Puccinia coronata f. sp. avenae)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2009Lena H Dimberg Abstract BACKGROUND: Avenanthramides, health-beneficial phenols in oats, are produced in response to incompatible races of the crown rust fungus, Puccinia coronata, in seedlings of greenhouse-grown oats. This study aimed to elucidate whether avenanthramides and/or other phenolic compounds, together with the activities of phenylalanine ammonia lyase (PAL), phenoloxidase (PO) and the avenanthramide biosynthetic enzyme hydroxycinnamoyl-CoA:hydroxyanthranilate- N -hydroxycinnamoyl transferase (HHT), are associated with crown rust infection in mature field-grown oats. Nine oat (Avena sativa L.) genotypes with wide variation in crown rust resistance were exposed to naturally occurring fungal spores during the growth period. RESULTS: In the spikelets avenanthramides as well as HHT activities were more abundant in the crown rust resistant genotypes, whereas p -coumaric and caffeic acids were more abundant in the susceptible ones. In the leaves avenanthramides were not associated with resistance. Instead two unknown compounds correlated negatively with the rust score. Phenols released by alkaline hydrolysis and PAL and PO activities were not related to rust infection, either in spikelets or in the leaves. CONCLUSION: Because grains of crown rust-resistant oat genotypes seemed to have higher endogenous levels of health-promoting avenanthramides, use of resistant oats may contribute to a food raw material with health-beneficial effects. Copyright © 2009 Society of Chemical Industry [source] L-carnitine supplementation in the dialysis population: Are Australian patients missing out? (Review Article)NEPHROLOGY, Issue 1 2008STEPHANIE E REUTER SUMMARY: It has been widely established that patients with end-stage renal disease undergoing chronic haemodialysis therapy exhibit low endogenous levels of L-carnitine and elevated acylcarnitine levels; however, the clinical implication of this altered carnitine profile is not as clear. It has been suggested that these disturbances in carnitine homeostasis may be associated with a number of clinical problems common in this patient population, including erythropoietin-resistant anaemia, cardiac dysfunction, and dialytic complications such as hypotension, cramps and fatigue. In January 2003, the Centers for Medicare and Medicaid Services (USA) implemented coverage of intravenous L-carnitine for the treatment of erythropoietin-resistant anaemia and/or intradialytic hypotension in patients with low endogenous L-carnitine concentrations. It has been estimated that in the period of 1998,2003, 3.8,7.2% of all haemodialysis patients in the USA received at least one dose of L-carnitine, with 2.7,5.2% of patients receiving at least 3 months of supplementation for one or both of these conditions. The use of L-carnitine within Australia is virtually non-existent, which leads us to the question: Are Australian haemodialysis patients missing out? This review examines the previous research associated with L-carnitine administration to chronic dialysis patients for the treatment of anaemia, cardiac dysfunction, dyslipidaemia and/or dialytic symptoms, and discusses whether supplementation is warranted within the Australian setting. [source] Thermoperiod affects the diurnal cycle of nitrate reductase expression and activity in pineapple plants by modulating the endogenous levels of cytokininsPHYSIOLOGIA PLANTARUM, Issue 3 2009Luciano Freschi Nitrate reductase (NR, EC 1.6.6.1) activity in higher plants is regulated by a variety of environmental factors and oscillates with a characteristic diurnal rhythm. In this study, we have demonstrated that the diurnal cycle of NR expression and activity in pineapple (Ananas comosus, cv. Smooth Cayenne) can be strongly modified by changes in the day/night temperature regime. Plants grown under constant temperature (28°C light/dark) showed a marked increase in the shoot NR activity (NRA) during the first half of the light period, whereas under thermoperiodic conditions (28°C light/15°C dark) significant elevations in the NRA were detected only in the root tissues at night. Under both conditions, increases in NR transcript levels occurred synchronically about 4 h prior to the corresponding elevation of the NRA. Diurnal analysis of endogenous cytokinins indicated that transitory increases in the levels of zeatin, zeatin riboside and isopentenyladenine riboside coincided with the accumulation of NR transcripts and preceded the rise of NRA in the shoot during the day and in the root at night, suggesting these hormones as mediators of the temperature-induced modifications of the NR cycle. Moreover, these cytokinins also induced NRA in pineapple when applied exogenously. Altogether, these results provide evidence that thermoperiodism can modify the diurnal cycle of NR expression and activity in pineapple both temporally and spatially, possibly by modulating the day/night changes in the cytokinin levels. A potential relationship between the day/night NR cycle and the photosynthetic pathway performed by the pineapple plants (C3 or CAM) is also discussed. [source] Protochlorophyllide-independent import of two NADPH:Pchlide oxidoreductase proteins (PORA and PORB) from barley into isolated plastidsPHYSIOLOGIA PLANTARUM, Issue 3 2000Clas Dahlin The enzyme catalysing the reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide), NADPH:Pchlide oxidoreductase (POR; EC 1.6.99.1), is a nuclear-encoded protein that is post-translationally imported to the plastid. In barley and Arabidopsis thaliana, the reduction of Pchlide is controlled by two different PORs, PORA and PORB. To characterise the possible Pchlide dependency for the import reaction, radiolabelled precursor proteins of barley PORA and PORB (pPORA and pPORB, respectively) were used for in vitro assays with isolated plastids of barley and pea with different contents of Pchlide. To obtain plastids with different endogenous levels of Pchlide, several methods were used. Barley plants were grown in darkness or in greenhouse conditions for 6 days. Alternatively, greenhouse-grown pea plants were incubated for 4 days in darkness before plastid isolation, or chloroplasts isolated from greenhouse-grown plants were incubated with , -aminolevulinic acid (ALA), an early precursor in the Chl biosynthesis resulting in elevated Pchlide contents in the plastids. Both barley pPORA and pPORB were effectively imported into barley and pea chloroplasts isolated from the differentially treated plants, including those isolated from greenhouse-grown plants. The absence or presence of Pchlide did not significantly affect the import capacity of barley pPORA or pPORB. Assays performed on stroma-enriched fractions from chloroplasts and etioplasts of barley indicated that no post-import degradation of the proteins occurred in the stroma, irrespective of whether the incubation was performed in darkness or in light. [source] shk1-D, a dwarf Arabidopsis mutant caused by activation of the CYP72C1 gene, has altered brassinosteroid levelsTHE PLANT JOURNAL, Issue 1 2005Naoki Takahashi Summary Brassinosteroids (BRs) are plant steroidal hormones that regulate plant growth and development. An Arabidopsis dwarf mutant, shrink1 -D (shk1-D), was isolated and the phenotype was shown to be caused by activation of the CYP72C1 gene. CYP72C1 is a member of the cytochrome P450 monooxygenase gene family similar to BAS1/CYP734A1 that regulates BR inactivation. shk1-D has short hypocotyls in both light and dark, and short petioles and siliques. The seeds are also shortened along the longitudinal axis indicating CYP72C1 controls cell elongation. The expression of CPD, TCH4 and BAS1 were altered in CYP72C1 overexpression transgenic lines and endogenous levels of castasterone, 6-deoxocastasterone and 6-deoxotyphasterol were also altered. Unlike BAS1/CYP734A1 the expression of CYP72C1 was not changed by application of exogenous brassinolide. We propose that CYP72C1 controls BR homeostasis by modulating the concentration of BRs. [source] Signaling requirements and role of salicylic acid in HRT - and rrt -mediated resistance to turnip crinkle virus in ArabidopsisTHE PLANT JOURNAL, Issue 5 2004A.C. Chandra-Shekara Summary Inoculation of turnip crinkle virus (TCV) on the resistant Arabidopsis ecotype Di-17 elicits a hypersensitive response (HR), which is accompanied by increased expression of pathogenesis-related (PR) genes. Previous genetic analyses revealed that the HR to TCV is conferred by HRT, which encodes a coiled-coil (CC), nucleotide-binding site (NBS) and leucine-rich repeat (LRR) class resistance (R) protein. In contrast to the HR, resistance to TCV requires both HRT and a recessive allele at a second locus designated rrt. Here, we demonstrate that unlike most CC-NBS-LRR R genes, HRT/rrt -mediated resistance is dependent on EDS1 and independent of NDR1. Resistance is also independent of RAR1 and SGT1. HRT/rrt -mediated resistance is compromised in plants with reduced salicylic acid (SA) content as a consequence of mutations eds5, pad4, or sid2. By contrast, HR is not affected by mutations in eds1, eds5, pad4, sid2, ndr1, rar1, or sgt1b. Resistance to TCV is restored in both SA-deficient Di-17 plants expressing the nahG transgene and mutants containing the eds1, eds5, or sid2 mutations by exogenous application of SA or the SA analog benzo(1,2,3)thiadiazole-7-carbothioic acid (BTH). In contrast, SA/BTH treatment failed to enhance resistance in HRT pad4, Col-0, or hrt homozygous progeny of a cross between Di-17 and Col-0. Thus, HRT and PAD4 are required for SA-induced resistance. Exogenously supplied SA or high endogenous levels of SA, due to the ssi2 mutation, overcame the suppressive effects of RRT and enhanced resistance to TCV, provided the HRT allele was present. High levels of SA upregulate HRT expression via a PAD4 -dependent pathway. As Col-0 transgenic lines expressing high levels of HRT were resistant to TCV, but lines expressing moderate to low levels of HRT were not, we conclude that SA enhances resistance in the RRT background by upregulating HRT expression. These data suggest that the HRT-TCV interaction is unable to generate sufficient amounts of SA required for a stable resistance phenotype, and the presence of rrt possibly corrects this deficiency. [source] Spatio-temporal expression of patatin-like lipid acyl hydrolases and accumulation of jasmonates in elicitor-treated tobacco leaves are not affected by endogenous levels of salicylic acidTHE PLANT JOURNAL, Issue 5 2002Sandrine Dhondt Summary We have previously isolated three tobacco genes (NtPat) encoding patatin-like proteins, getting rapidly induced during the hypersensitive response (HR) to tobacco mosaic virus, in advance to jasmonate accumulation. NtPAT enzymes are lipid acyl hydrolases that display high phospholipase A2 (PLA2) activity and may mobilize fatty acid precursors of oxylipins. Here, we performed a detailed study of NtPat gene regulation under various biotic and abiotic stresses. PLA2 activity was poorly induced in response to drought, wounding, reactive oxygen intermediates, salicylic acid (SA) or methyl-jasmonate (MJ) whereas the ethylene (ET) precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), provoked a moderate induction. In contrast, PLA2 activity was strongly induced when ACC was combined with MJ, and in response to the bacterium Erwinia carotovora or to the fungus Botrytis cinerea, as well as to treatment with ,-megaspermin, a cell death-inducing protein elicitor. A simplified system based on the infiltration of ,-megaspermin into leaves was used to dissect the spatio-temporal activation of PLA2 activity with regards to the accumulation of jasmonates and to the influence of endogenous SA. NtPat -encoded PLA2 activity was rapidly induced in the infiltrated zone before the appearance of cell death and with some delay in the surrounding living cells. A massive accumulation of 12-oxo-phytodienoic and jasmonic acids occurred in the elicitor-infiltrated zone, but only low levels were detectable outside this area. A similar picture was found in SA-deficient plants, showing that in tobacco, accumulation of jasmonates is not affected by the concomitant HR-induced build-up of endogenous SA. Finally, ET-insensitive plants showed a weakened induction of PLA2 activity outside the elicitor-infiltrated tissue. [source] Fox-2 protein regulates the alternative splicing of scleroderma-associated lysyl hydroxylase 2 messenger RNA,ARTHRITIS & RHEUMATISM, Issue 4 2010Puneet Seth Objective Scleroderma (systemic sclerosis [SSc]) is a complex connective tissue disorder characterized by hardening and thickening of the skin. One hallmark of scleroderma is excessive accumulation of collagen accompanied by increased levels of pyridinoline collagen crosslinks derived from hydroxylysine residues in the collagen telopeptide domains. Lysyl hydroxylase 2 (LH2), an important alternatively spliced enzyme in collagen biosynthesis, acts as a collagen telopeptide hydroxylase. Changes in the pattern of LH2 alternative splicing, favoring increased inclusion of the alternatively spliced LH2 exon 13A, thereby increasing the levels of the long transcript of LH2 (LH2[long]), are linked to scleroderma disease. This study was undertaken to examine the role played by RNA binding protein Fox-2 in regulating exon 13A inclusion, which leads to the generation of scleroderma-associated LH2(long) messenger RNA (mRNA). Methods Phylogenetic sequence analysis of introns flanking exon 13A was performed. A tetracycline-inducible system in T-Rex 293 cells was used to induce Fox-2 protein, and endogenous LH2(long) mRNA was determined by reverse transcriptase,polymerase chain reaction. An LH2 minigene was designed, validated, and used in Fox-2 overexpression and mutagenesis experiments. Knockdown of Fox-2 was performed in mouse embryonic fibroblasts and in fibroblasts from SSc patients. Results Overexpression of Fox-2 enhanced the inclusion of exon 13A and increased the generation of LH2(long) mRNA, whereas knockdown of Fox-2 decreased LH2(long) transcripts. Mutational analysis of an LH2 minigene demonstrated that 2 of the 4 Fox binding motifs flanking LH2 exon 13A are required for inclusion of exon 13A. In early passage fibroblasts derived from patients with scleroderma, the knockdown of Fox-2 protein significantly decreased the endogenous levels of LH2(long) mRNA. Conclusion Our findings indicate that Fox-2 plays an integral role in the regulation of LH2 splicing. Knockdown of Fox-2 and other methods to decrease the levels of fibrosis-associated LH2(long) mRNA in primary scleroderma cells may suggest a novel approach to strategies directed against scleroderma. [source] Development and validation of an on-line two-dimensional reversed-phase liquid chromatography,tandem mass spectrometry method for the simultaneous determination of prostaglandins E2 and F2, and 13,14-dihydro-15-keto prostaglandin F2, levels in human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 3 2009Junji Komaba Abstract We developed and validated an on-line reverse-phase two-dimensional LC/MS/MS (2D-LC/MS/MS) system for simultaneous determination of the levels of prostaglandin (PG) E2 as well as PGF2, and its metabolite 13,14-dihydro-15-keto PGF2, (F2, -M) in human plasma. Analytes were extracted by a three-step solid-phase extraction. Samples were then analyzed by on-line 2D-LC/MS/MS with electrospray ionization in negative mode. The 2D-LC system is composed of two reverse-phase analytical columns with a trapping column linking the two analytical columns. While an acidic buffer was used for both separation dimensions, differing organic solvents were employed for each dimension: methanol for the first and acetonitrile for the second to increase resolving power. The 2D-LC/MS/MS method was highly selective and sensitive with a significantly lower limit of quantitation (0.5 pg/mL for PGE2 and 2.5 pg/mL for PGF2, and F2, -M, respectively). Linearity of the 2D-LC/MS/MS system was demonstrated for the calibration ranges of 0.5,50 pg/mL for PGE2 and 2.5,500 pg/mL for PGF2, and F2, -M, respectively. Acceptable precision and accuracy were obtained throughout the calibration curve ranges. This highly selective and sensitive method was successfully utilized to determine the endogenous levels of PGE2, PGF2,, and F2, -M in plasma samples from six (four male and two female) normal volunteers. The mean concentrations for each analyte were 0.755 pg/mL for PGE2, 5.70 pg/mL for PGF2, and 9.48 pg/mL for F2, -M. Copyright © 2008 John Wiley & Sons, Ltd. [source] A PCR-based strategy to generate yeast strains expressing endogenous levels of amino-terminal epitope-tagged proteinsBIOTECHNOLOGY JOURNAL, Issue 4 2008Keith R. Booher Abstract An epitope tag introduced to a gene of interest (GOI) greatly increases the ease of studying cellular proteins. Rapid PCR-based strategies for epitope tagging a protein's C-terminus at its native gene locus are widely used in yeast. C-terminal epitope tagging is not suitable for all proteins, however. Epitope tags fused to the C-terminus can interfere with function of some proteins or can even be removed by C-terminal protein processing. To overcome such problems, proteins can be tagged with epitopes at their amino-termini, but generating yeast strains expressing N-terminal epitope tagged genes under control of the endogenous promoter at the native locus is comparatively more difficult. Strategies to introduce N-terminal epitope tags have been reported previously but often introduce additional sequences other than the epitope tag into the genome. Furthermore, N-terminal tagging of essential genes by current methods requires formation of diploid strains followed by tetrad dissection or expression of an additional copy of the GOI from a plasmid. The strategies described here provide a quick, facile means of epitope tagging the N-terminus of both essential and nonessential genes in a two-step PCR-based procedure. The procedure has the significant advantage of leaving tagged genes under the control of their endogenous promoters, and no additional sequences other than the epitope tag encoding nucleotides are inserted into the genome. [source] Oral R115866 in the treatment of moderate to severe facial acne vulgaris: an exploratory studyBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2007C.J. Verfaille Summary Background, R115866 (RambazoleTM; Barrier Therapeutics NV, Geel, Belgium), a new-generation retinoic acid metabolism-blocking agent, is a nonretinoid compound enhancing intracellularly the endogenous levels of all- trans -retinoic acid by blocking its catabolism. By virtue of this property, and the proven positive effects of retinoids in the treatment of acne, R115866 could potentially be a useful drug for acne. Objectives, To explore the efficacy, safety and tolerability of systemic R115866 in male patients with moderate to severe facial acne vulgaris (at least 15 papules and/or pustules and at least two nodulocystic lesions). Methods, In this exploratory trial, 17 patients were treated with oral R115866 1 mg once daily for 12 weeks, followed by a 4-week treatment-free period. Results, At the end of treatment (week 12, n = 16) a mean reduction in inflammatory lesion count of 77·4% (P < 0·001), in noninflammatory lesion count of 58·3% (P < 0·001) and in total lesion count of 76·0% (P < 0·001) was observed as compared with baseline. All lesion counts were significantly reduced from week 4 onwards. Mild side-effects were reported occasionally. Conclusions, The current data indicate that treatment with oral R115866 1 mg once daily for 12 weeks in patients with moderate to severe facial acne vulgaris is efficacious and well tolerated and merits further investigation. [source] | ||||||||||||||||||||||||||||