bluuebunny/crossref_metadata_2025 huggingface dataset:
Scientific Aspects That Justify the Benefits of the Mediterranean Diet
Authors: COVAS M. I. , MARRUGAT J. , FITÓ M. , ELOSUA R. , DE LA TORRE‐BORONAT C.
Published: July 2009

Abstract: The Mediterranean diet is now recognized as being both limited in toxicity and abundant in nutrient and non‐nutrient protective factors. A large body of basic, clinical and epidemiological studies have been developed in recent years to provide evidence of the benefits of the Mediterranean diet or its components on health. Evidence‐based medicine ranks randomized controlled clinical trials as providing the highest level of evidence and expert opinions the lowest. On the basis of these criteria, the current state of knowledge about Mediterranean diet in primary and secondary prevention of disease and mortality and morbidity as functions of the amount of alcoholic beverage consumption, is reviewed. Efficacy versus effectiveness, the role of basic and animal research, and bioavailability studies providing evidence is also discussed.
Thioredoxin Superfamily and Thioredoxin‐Inducing Agents
Authors: HIROTA KIICHI , NAKAMURA HAJIME , MASUTANI HIROSHI , YODOI JUNJI
Published: July 2009

Abstract: Mammalian thioredoxin (TRX) with redox‐active dithiol in the active site plays multiple roles in intracellular signaling and resistance against oxidative stress. TRX is induced by a variety of stresses including infectious agents as well as hormones and chemicals. TRX is secreted from activated cells such as HTLV‐I‐transformed T‐cells as a redox‐sensitive molecule with cytokine‐like and chemokine‐like activities. The promoter of the TRX gene contains a series of stress‐responsive elements. In turn, TRX promotes activation of transcription factors such as NF‐κB, AP‐1, and p53. We have reported that natural substances including estrogen, prostaglandins, and cAMP induce mRNA, protein, and secretion of TRX. These agents seemed to exert their physiological functions including cytoprotective actions partly through the induction of TRX without massive oxidative stress, which induces TRX strongly as well as other stress proteins. We report here a new TRX inducer substance, geranylgeranylacetone (GGA), which is originally derived from a natural plant constituent and has been used in the clinical field as an anti‐ulcer drug. We have demonstrated that GGA induces the messenger RNA and protein of TRX and affects the activation of transcription factors, AP‐1 and NF‐κB, and that GGA blunted ethanol‐induced cytotoxicity of cultured hepatocytes and gastrointestine mucosal cells. We will discuss a possible novel molecular mechanism of GGA, which is to protect cells via the induction of TRX and activation of transcription factors such as NF‐κB and AP‐1. Identification of the particular TRX‐inducing components may contribute to the elucidation of the molecular basis of the “French Paradox,” in which good red wines are beneficial for the cardiovascular system.
Resveratrol, a Component of Wine and Grapes, in the Prevention of Kidney Disease
Authors: BERTELLI ALBERTO A.E. , MIGLIORI MASSIMILIANO , PANICHI VINCENZO , ORIGLIA NICOLA , FILIPPI CRISTINA , DAS DIPAK K. , GIOVANNINI LUCA
Published: July 2009

Abstract: Ischemia is an inciting factor in 50% of incidences of acute renal failure, and it increases the risk of organ rejection after renal transplantation. We have previously demonstrated that resveratrol (RSV) reduces ischemia‐reperfusion (I/R) injury of rat kidney both by antioxidant and anti‐inflammatory mechanisms. However, a clear morphological demonstration of this activity has not been made. To answer this question we have performed a new set of experiments following the experimental protocol reported below to investigate the effects of I/R injury and RSV pretreatment on kidney morphology by computerized morphometric analysis. Both renal arteries were clamped for 40 minutes in 40 male Wistar rats (b.w. 220 ± 20 g); 20 rats were pretreated with RSV 1 μM e.v. 40 minutes before clamping. All animals were reperfused for 24 hours and then sacrificed. Histological examination showed tissue conservation in treated rats. I/R‐induced glomerular collapse (as revealed by mean glomerular volume and glomerular shape factor) was significantly reduced by RSV pretreatment. Capillary tuft/Bowman's capsule area ratio was enhanced in the I/R group suggesting tubular hypertension. RSV pre‐treatments significantly reduced this parameter to the control value. The number of platelet clots in the capillary tuft and tubular necrosis were also reduced by RSV versus I/R group. l‐NAME administration worsened both functional and structural damage. Finally, cGMP urinary levels were markedly reduced from 12.1 ± 8.4 nmol/day to 0.10 ± 0.10 nmol/day in the I/R group. RSV provided cGMP (5.01 ± 1.5 nmol/day, P < 0.05). As expected, l‐NAME administration significantly reduced cGMP in urine (0.71 ± 0.6 nmol/day). The present study confirms the protective effect of RSV pretreatment in I/R injury of rat kidney and suggests multiple mechanisms of action.
Polyphenols and Red Wine as Peroxynitrite Scavengers
Authors: ALVAREZ SILVIA , ZAOBORNYJ TAMARA , ACTIS‐GORETTA LUCAS , FRAGA CÉSAR G. , BOVERIS ALBERTO
Published: July 2009

Abstract: A novel chemiluminescent assay for evaluating peroxynitrite (ONOO−)‐scavenging capacity was developed. The experimental protocol ensures sensitivity and reproducibility of measurements. The addition of 0‐500 μM ONOO− to rat liver homogenate generated a luminous signal that was analyzed by chemiluminescence in a LKB Wallac liquid scintillation counter. The obtained optimal conditions were: 1‐2 mg/mL of homogenate protein in 120 mM KCl, 30 mM phosphate buffer (pH 7.4), and 220 μM ONOO− at 30°C. As polyphenols we used (+)‐catechin, (−)‐epicatechin, and myricetin. The most efficient of the compounds tested was myricetin with an IC50 of 20 μM. The effectiveness of this method was verified by evaluating the antioxidant ability of three red wine samples to decrease peroxynitrite‐initiated chemiluminescence. The ONOO−‐scavenging activity of wines measured by this assay was related to the phenolic level of the samples. The quickness and reliability of this assay makes it particularly suitable for a large‐scale screening of watery food extracts.
Comparative Study on the Antioxidant Capacity of Wines and Other Plant‐Derived Beverages
Authors: ACTIS‐GORETTA LUCAS , MACKENZIE GERARDO G. , OTEIZA PATRICIA I. , FRAGA CÉSAR G.
Published: July 2009

Abstract: Consistent epidemiological data point to a reduced morbidity and mortality from coronary heart disease and atherosclerosis in people consuming plant‐derived beverages such as tea or wine. We studied the antioxidant capacity of three red wines (W) and compared it those of tea and herbal “mate” tea infusions. The antioxidant capacity was evaluated measuring: (1) the inhibition of the luminol‐induced chemiluminescence assay (TRAP); (2) the inhibition of 2.2′‐thiobarbituric‐reactive substances (TBARS) formation in liposomes by fluorescence; (3) the protection of Jurkat cells from AMVN‐induced oxidation, measuring the oxidation of 5‐(and‐6)‐carboxy‐2′7′‐dichlorodihydrofluorescein diacetate to a fluorescent derivative. The polyphenolic content was estimated spectrophotometrically and by HPLC with electrochemical detection. All three beverages provided antioxidant protection in the three assays in a dose‐dependent manner. Significant and positive correlations were found between antioxidant capacity and total polyphenol content, especially in the Jurkat cell oxidation assay (r: 0.96, p < 0.01). Results suggest that these dietary components could be a source of antioxidants that protect from oxidative stress. Further studies of absorption and metabolism of the active compounds will judge the physiological relevance of these results for human health.
A Queue Paradigm Formulation for the Effect of Large‐Volume Alcohol Intake on the Lower Urinary Tract
Authors: ARUN C. P.
Published: July 2009

Abstract: We examine the urologic consequences of large‐volume alcohol intake in light of recent advances in hollow viscera biomechanics and urinary tract pharmacology. Recent studies have shown that alcohol is depressive on the isolated rabbit detrusor. Patients teetering on or having manifest pelvi‐ureteric junction obstruction or bladder outflow obstruction have been known to demonstrate symptoms on alcohol consumption. In men over 50, the cause is usually an enlarged prostate. Loin pain is precipitated in the case of the former and urinary retention in the latter case after consuming alcohol. Causation is difficult to prove for ethical reasons as well as the practical difficulties in running a prospective trial. It appears that a combination of rapid fill (due to diuretic effects), a weakened pump (due to the depressive effect of alcohol at least with the detrusor) and outlet obstruction lead to the loin pain and urinary retention seen in clinical practice. People liable to urinary tract obstruction would be well advised to avoid large volume alcohol intakes.
Corrupt Captains and Convicts
Authors: NORRIE PHILIP
Published: July 2009

Abstract: Australia is unique in that so many of its wine companies were founded by members of the medical profession. The First Fleet, which brought the first convicts and settlers to Australia in 1787, was delayed until wine was provided as a medicine for the long voyage from England. Australia's wine doctors were advocating the use of wine as a medicine 200 years before the French Paradox.
Genetic Approaches to Craniofacial Tissue Repair
Authors: BONADIO JEFFREY , CUNNINGHAM MICHAEL L.
Published: July 2009

Abstract: This review discusses in some detail the opportunities and challenges of applying gene therapy to the important clinical problem of wound repair and regeneration.
Different Osteochondral Potential of Clonal Cell Lines Derived from Adult Human Trabecular Bone
Authors: OSYCZKA ANNA M. , NÖTH ULRICH , DANIELSON KEITH G. , TUAN ROCKY S.
Published: July 2009

Abstract: Cells derived from human trabecular bones have been shown to have multipotential differentiation ability along osteogenic, chondrogenic, and adipogenic lineages. In this study, we have derived two clonal sublines of human trabecular bone cells by means of stable transduction with human papilloma virus E6/E7 genes. Our results showed that these clonal sublines differ in their osteochondral potential, but are equally adipogenic, indicative of the heterogeneous nature of the parental cell population. The availability of these cell lines should be useful for the analysis of the mechanisms regulating the differentiation of adult mesenchymal progenitor cells.
Emerging Design Principles in Biomaterials and Scaffolds for Tissue Engineering
Authors: GRIFFITH LINDA G.
Published: July 2009

Abstract: Biomaterials and scaffolds play an essential role in tissue engineering by guiding new tissue growth in vivo and in vitro. While adaptation of existing surgical materials has fulfilled some needs in the field, new applications demand better control of bulk properties such as degradation and of surface properties that control cell interactions. Advances in molecular cell biology are driving the incorporation of new biological moieties into materials, and a set of design principles based on quantitative analysis of key cellular processes involved in regeneration is emerging. At the same time, new materials‐processing methodologies are emerging to allow fabrication of these fragile materials into devices appropriate for delivery.
Polymer/Alginate Amalgam for Cartilage‐ Tissue Engineering
Authors: CATERSON E. J. , LI W. J. , NESTI L. J. , ALBERT T. , DANIELSON K. , TUAN R. S.
Published: July 2009

Abstract: Marrow stroma‐derived cells (MSC) are highly proliferative, multipotential cells that have been considered as ideal candidate cells for autologous tissue engineering applications. In this study, we have characterized the chondrogenic potential of human MSCs in both a PLA/alginate amalgam and pure PLA macrostructure as model three‐dimensional constructs to support both chondrogenic differentiation and proliferation following TGF‐β treatment. MSCs were seeded in experimental groups that consisted of PLA‐loaded constructs and PLA/alginate amalgams with and without recombinant human TGF‐β1. Chondrogenesis of the PLA and the PLA/alginate amalgam cultures was assessed at weekly intervals by histology, immunohistochemistry, scanning electron microscopy, sulfate incorporation, and RT‐PCR. Chondrogenic differentiation occurs within a polymeric macrostructure with TGF‐β1 treatment as indicated by histological, immunohistochemical, sulfate incorporation, and gene expression profiles. This macrostructure can be further encased in an alginate gel/solution to optimize cell shape and to confine growth factors and cells within the polymer construct, while the polymeric scaffold provides appropriate mechanical/tissue support. The stable three‐dimensional PLA/alginate amalgam represents a novel candidate system of mesenchymal chondrogenesis, which is amendable to investigation of mechanical and biological factors that normally modulate cartilage development and formation as well as a potential tissue engineering construct for cartilage repair.
Accelerated and Improved Osteointegration of Implants Biocoated with Bone Morphogenetic Protein 2 (BMP‐2)
Authors: JENNISSEN HERBERT P.
Published: July 2009

Abstract: A concept and methodology are presented for the direct biocoating of implantable metals like titanium and stainless steel with bone morphogenetic protein 2 (BMP‐2) for future applications as cementless bone or dental prostheses. Such bioactive surfaces can influence cells and tissues by chemotactic as well as juxtacrine mechanisms. Reference is made to first experiments in sheep and rabbits in which BMP‐2 coatings impressively increased the osteoinductive potential of titanium implants.
Molecular Signaling in Bioengineered Tissue Microenvironments
Authors: BOTTARO DONALD P. , LIEBMANN‐VINSON ANDREA , HEIDARAN MOHAMMAD A.
Published: July 2009

Abstract: Biological tissues and organs consist of specialized living cells arrayed within a complex structural and functional framework known generally as the extracellular matrix (ECM). The great diversity observed in the morphology and composition of the ECM contributes enormously to the properties and function of each organ and tissue. For example, the ECM contributes to the rigidity and tensile strength of bone, the resilience of cartilage, the flexibility and hydrostatic strength of blood vessels, and the elasticity of skin. The ECM is also important during growth, development, and wound repair: its own dynamic composition acts as a reservoir for soluble signaling molecules and mediates signals from other sources to migrating, proliferating, and differentiating cells. Artificial three‐dimensional substitutes for ECM, called tissue scaffolds, may consist of natural or synthetic polymers or a combination of both. Scaffolds have been used successfully alone and in combination with cells and soluble factors to induce tissue formation or promote tissue repair. Appropriate numbers of properly functioning living cells are central to many tissue‐engineering strategies, and significant efforts have been made to identify and propagate pluripotent stem cells and lineage‐restricted progenitor cells. The study of these and other living cells in artificial microenvironments, in turn, has led to the identifcation of signaling events important for their controlled proliferation, proper differentiation, and optimal function.
p38 MAP Kinase Regulation of AP‐2 Binding in TGF‐β1‐Stimulated Chondrogenesis of Human Trabecular Bone‐Derived Cells
Authors: TULI R. , SEGHATOLESLAMI M. R. , TULI S. , HOWARD M. S. , DANIELSON K. G. , TUAN R. S.
Published: July 2009

Abstract: Collagenase‐treated, explanted human trabecular‐bone chips are an excellent source of osteoblast‐like cells. We have recently shown the multiple differentiation potential of these cells; in addition to osteogenesis and adipogenesis, these cells also undergo chondrogenesis when maintained as high‐density pellet cultures (250,000 cells/pellet) in a serum‐free, chemically defined medium stimulated with TGF‐β1 (10 ng/mL). In this investigation, we have analyzed how transactivating nuclear transcription factors, specifically AP‐2 and SP‐1, may interact with common cis‐acting elements found in the regulatory region of cartilage‐specific genes as part of the signal transduction mechanism of TGF‐β1 and p38 during chondrogenesis of human trabecular bone‐derived multipotential cells. Both TGF‐β1 stimulation and p38 MAP kinase activation affect the binding of AP‐2 as well as SP‐1 to oligonucleotides with sequence similarity to the overlapping AP‐2/SP‐1 sites found in the putative 52‐bp immediate upstream regulatory region and the 5′‐untranslated region of the human aggrecan gene. Electrophoretic mobility shift assays show that TGF‐β1 treatment of the bone‐derived cells inhibits AP‐2 DNA binding but enhances the DNA binding ability of SP‐1. Additionally, treatment of these TGF‐β1‐stimulated cells with p38 MAP kinase inhibitor, SB203580, rescued the AP‐2 DNA binding but did not affect SP‐1 DNA binding. These findings indicate that AP‐2 DNA binding is the target of both TGF‐β1 and p38 MAP kinase signaling pathways and suggest a possible signal transduction cascade whereby TGF‐β1 induction of chondrogenesis involves the activation of p38 MAP kinase and the subsequent inhibition of DNA binding by AP‐2, thereby preventing the transcriptional repression of the aggrecan gene.
Preconditioning‐Mediated Neuroprotection
Authors: ANDOH TSUGUNOBU , CHOCK P. BOON , CHIUEH CHUANG C.
Published: July 2009

Abstract: Preconditioning adaptation induced by transient ischemia can increase brain tolerance to oxidative stress, but the underlying neuroprotective mechanisms are not fully understood. Recently, we developed a human brain‐derived cell model to investigate preconditioning mechanism in SH‐SY5Y neuroblastoma cells.1 Our results demonstrate that a non‐lethal serum deprivation‐stress for 2 h (preconditioning stress) enhanced the tolerance to a subsequent lethal oxidative stress (24 h serum deprivation) and also to 1‐methyl‐4‐phenyl‐pyridinium (MPP+).2 Two‐hour non‐lethal preconditioning stress increased the expression of neuronal nitric oxide (NOS1/nNOS) mRNA, Fos, Ref‐1, NOS protein, and then nitric oxide (•NO) production. As well as MnSOD expression, the •NO‐cGMP‐PKG pathway mediated the preconditioning‐induced upregulation of antiapoptotic protein Bcl‐2 and the downregulation of adaptor protein p66shc. We also propose that cGMP‐mediated preconditioning‐induced adaptation against oxidative stress may be due to the synthesis of a new protein, such as thioredoxin (Trx) since the protective effect can be blocked by Trx reductase inhibitor.3 The antioxidative potency of Trx was approximately 100 and 1,000 times greater than GSNO and GSH, respectively. These results suggest that •NO‐cGMP‐PKG signaling pathway plays an important role in the preconditioning‐induced neuroprotection, and perhaps cardioprotection, against oxidative stress.
NO‐Mediated Chemoresistance in C6 Glioma Cells
Authors: YANG DING‐I. , YIN JIU‐HAW , MISHRA SNIGDHA , MISHRA RAJ , HSU CHUNG Y.
Published: July 2009

Abstract:Expression of inducible nitric oxide synthase (iNOS) in malignant glioma and other tumors has been extensively documented. Massive production of NO by iNOS has been shown to exert tumoricidal effects. However, NO may enhance vasodilation and promote neovascularization, thereby facilitating tumor growth. Compared to the effects of NO on tumor cell death and survival, correlation between NO and cytotoxicity of chemotherapeutic reagents in glioma have been less well characterized. Another gene product often linked to tumor malignancy is hypoxia‐inducible factor‐1 (HIF‐1). HIF‐1 is a transcription factor that renders malignant tumors adaptive to hypoxic stress during massive vascularization and tumor invasion. Interestingly, HIF‐1 also contributes to iNOS induction under hypoxia. We have characterized the interrelationship between iNOS, HIF‐1 and chemoresistance. We note that increased NO synthesis by cytokine exposure or iNOS overexpression neutralized the cytotoxicity of 1,3‐bis(2‐chloroethyl)‐1‐nitrosourea (BCNU) and 1‐(2‐chloroethyl)‐3‐cyclohexyl‐1‐nitrosourea (CCNU), but not cisplatin, in rat C6 glioma cells. Both BCNU and CCNU are chloroethylnitrosoureas that kill tumor cells via carbamoylating and alkylating actions. Further studies indicated that iNOS only neutralized carbamoylating action of chloroethylnitrosoureas. Expression of iNOS may inhibit HIF‐1 activity under hypoxia in C6 glioma cells transfected with a VEGF promoter‐driven luciferase gene. Pretreatment of C6 cells withN‐acetyl‐l‐cysteine (NAC), an antioxidant, nullified the inhibitory effect of iNOS on HIF‐1 binding. That NO generated by iNOS expression inhibits HIF‐1 activity in hypoxic C6 cells reveals a negative feedback loop in the HIF‐1 → iNOS cascade. Together these results suggest a complicated role of NO in malignant tumor growth, survival and invasion.
Role of Nitric Oxide in Myocardial Preconditioning
Authors: DAWN BUDDHADEB , BOLLI ROBERTO
Published: July 2009

Abstract: Ischemic preconditioning (PC) is a polygenic defensive cellular adaptive phenomenon whereby brief ischemic stimuli render the heart resistant to subsequent similar stress. The late phase of ischemic PC lasts for three to four days, protects against both myocardial stunning and infarction, and thus has considerable clinical relevance. Diverse signaling molecules released by a sublethal ischemic stress initiate a complex signal transduction cascade that modulates the expression of cardioprotective genes. Nitric oxide (NO), generated by the endothelial NO synthase (NOS) and acting via the formation of reactive oxygen species, activates the ε isoform of protein kinase C (PKC), which activates the Src family of protein tyrosine kinases (Src and Lck) and transcription factors (nuclear factor‐κB, and possibly others), with resultant upregulation of the inducible NOS (iNOS) gene and protein expression. iNOS, and other cardioprotective proteins, including cyclooxygenase‐2 and aldose reductase, confer resistance to subsequent ischemic stress. This delayed protection can also be mimicked, in the absence of ischemia, by administering NO‐releasing agents, a situation that can be potentially exploited for cardioprotection in clinical situations. Identification of this novel bifunctional (trigger and mediator) role played by NO in cardiac protection, not only advances the knowledge regarding its signaling functions, but also offers a potential therapeutic strategy for patients with coronary artery disease. The purpose of this review is to summarize the current evidence in support of this critical role played by NO in ischemic PC.
l‐Citrulline Recycle for Synthesis of NO in Cerebral Perivascular Nerves and Endothelial Cells
Authors: LEE TONY J.F. , YU JUN‐GE
Published: July 2009

Abstract:Recycle of l‐citrulline to form l‐arginine in cerebral perivascular nerves has been well described, providing direct evidence that nitric oxide (NO) is synthesized and released from these nerves to act as the transmitter for vasodilation. NO is also synthesized and released from cerebral endothelial cells, involving l‐citrulline conversion to l‐arginine. Evidence for the presence of enzymes involved in the conversion, however, has not been shown. The presence of nitric oxide synthase (NOS), argininosuccinate synthetase (ASS), and argininosuccinate lyase (ASL), and their coexistence with NADPH‐diaphorase (NADPHd), a marker for NOS, in endothelial cells of middle cerebral arteries and the circle of Willis of the pig, therefore, were examined using combined immunohistochemical and histochemical techniques. NOS‐, ASS‐, and ASL‐immunoreactivities were found in almost all endothelial cells of all cerebral arteries examined. All ASS‐, ASL‐, and NOS‐immunoreactive (I) endothelial cells also stained positively for NADPHd, suggesting that ASS, ASL, and NOS were colocalized in endothelial cells of middle cerebral arteries and the circle of Willis. These results provide morphological evidence that cerebral vascular endothelial cells like cerebral perivascular nerves contain enzymes necessary for recycling l‐citrulline to l‐arginine to synthesize NO via an argininosuccinate (AS) pathway.
Glial‐Neuronal Transfer of Arginine andS‐Nitrosothiols in Nitric Oxide Transmission
Authors: DO K. Q. , GRIMA G. , BENZ B. , SALT T. E.
Published: July 2009

Abstract:The arginine‐nitric oxide (Arg‐NO) and theS‐nitrosothiols systems, two less well‐studied aspects of NO transmission in the central nervous system, are reviewed. A growing body of evidence suggested that they play a crucial role in NO synthesis and activity. l‐Arginine, the NO precursor, is predominantly localized in glia. Together within vitroandin vivoresults of arginine release, this suggests a transfer of arginine from glia to neurons in order to supply NO synthase with its substrate. NO biosynthesis may thus involve the co‐occurrence of the glial‐neuronal transfer of arginine and of NOS activation. The arginine availability may shed light on the dual, beneficial and toxic effects of NO. At low arginine concentrations, neuronal NO synthase generates NO and superoxide, favouring the production of the toxin peroxynitrite. NMDA‐induced excitotoxicity in neuronal cells is dependent on arginine availability and glia may play a neuroprotective role by supplying arginine. The reversibleS‐nitros(yl)ation of thiol containing molecules may represent an important cellular signal transduction mechanism, probably comparable to phosphorylation.S‐nitrosothiols, in particular through the presence and release ofS‐nitroso‐cysteinylglycine in sensory thalamus, may act as a local buffering system in NO transmission. This may represent a novel specific facilitating mechanism in order to enhance transmission of persistent stimuli.
The Roles of Nitric Oxide in Dorsal Root Ganglion Neurons
Authors: THIPPESWAMY THIMMASETTAPPA , MORRIS RICHARD
Published: July 2009

Abstract: The functions of nitric oxide (NO) in primary somatosensory neurons are reviewed. During the early development of these neurons the neuronal isoform of nitric oxide synthase (nNOS) is expressed during neurite extension. As their axons extend peripherally and start to take up nerve growth factor (NGF), nNOS starts to disappear from the majority of these neurons. A small number (less than 5%) continue to express nNOS, and for this small population NO may have a role in synaptic transmission. Following peripheral nerve section in adult rats, nNOS is reexpressed in many small peptidergic DRG neurons that have been axotomized. At the same time cGMP synthesis is increased in satellite glia cells. From culture studies, it was established that NGF negatively regulates nNOS synthesis in DRG neurons and that block of NO production leads to neuronal death. Further recent data is reviewed that supports the view that NO has a neuroprotective action preventing loss of DRG neurons and facilitates regeneration.
Spatial and Temporal Correlation of Nitric Oxide Synthase Expression with CuZn‐Superoxide Dismutase Reduction in Motor Neurons following Axotomy
Authors: YU WAN‐HUA AMY
Published: July 2009

Abstract: Axotomized neurons expressing neuronal nitric oxide synthase (nNOS) may use nitric oxide (NO), known for its antioxidant activities and ability to scavenge free radicals, to protect against oxidative stress. This hypothesis was tested by immunohistochemical examination of superoxide dismutase (SOD) in neurons of the hypoglossal nucleus (HGN) and dorsal motor nucleus of the vagus nerve (DMV) one day to ten weeks after unilateral hypoglossal nerve crush or avulsion combined with vagus nerve crush in adult rats, and also in neurons of the anterior horn (AH) one week after unilateral sciatic nerve crush or avulsion. In the HGN, emergence of nNOS coincided temporally with reduction of CuZn‐SOD immunoreactivity (ir), and the level of reduction correlated with that of nNOS induction, differing only in magnitude between nerve crush and nerve avulsion. The two nerve lesion models further revealed the concurrence of nNOS abatement with recovery of CuZn‐SOD ir, and absence of nNOS abatement with persistent low CuZn‐SOD ir. In the AH, reduced CuZn‐SOD ir was localized in the segments containing nNOS positive neurons as a result of sciatic nerve avulsion. CuZn‐SOD ir was unchanged in the absence of nNOS induction following sciatic nerve crush. DMV neurons were devoid of CuZn‐SOD ir. However, increased Mn‐SOD ir one and two weeks post crush was similar to that in HGN neurons. DMV neurons lacked both nNOS abatement and CuZn‐SOD ir, which may explain their particular vulnerability to cell death from axotomy in comparison with other peripheral neurons. These data suggest that axotomy‐induced nNOS expression is causally linked to oxidative stress, and that NO is neuroprotective, but can become neurodestructive when produced in excess.
Nitric Oxide Transport and Storage in the Cardiovascular System
Authors: MULLER BERNARD , KLESCHYOV ANDREI L. , ALENCAR JACICARLOS L. , VANIN ANATOLY , STOCLET JEAN‐CLAUDE
Published: July 2009

Abstract:Despite short halflife in biological fluids, nitric oxide (NO) can produce remote or long lasting effect in the cardiovascular system. Long distance transport or local storage of NO might explain these effects. In blood, recent findings suggest that in addition to being a major consumption pathway, interaction of NO with hemoglobin may permit O2‐governed transport of NO (asS‐nitrosohemoglobin) to tissues in which NO may be released together with O2, via transnitrosation of a transport protein. In blood vessels, two different putative NO stores have been characterized. The first is the photosensitive store, formed from endothelium‐derived NO. The mechanism of NO release from this store in the body (in absence of light) and its physiological relevance are unknown. The second store is generated in conditions of high tissue NO levels, as a consequence of the inducible NO synthase activity or in various stress conditions. This NO store involves formation of protein‐bound dinitrosyl iron complexes orS‐nitrosated proteins, or both. Low molecular weight thiols can displace NO from these stores and probably transfer it to target membrane protein(s) such as K+channels, via transnitrosation reactions. These stores may be involved in defence mechanisms against inflammation or stress. Thus, NO transport and storage mechanisms may be implicated in a variety of NO effects. The mechanisms of their formation and of NO release and their physiologic and pathophysiologic relevance deserve further investigations.
Thioredoxin‐Related Regulation of NO/NOS Activities
Authors: SHAO LI‐EN , TANAKA TETSUYA , GRIBI RUBY , YU JOHN
Published: July 2009

Abstract: The role of regulation of nitric oxide synthase (NOS) activity in mitigating oxidative stress in neonatal lungs and contributing to pulmonary vasodilation at birth is still unclear. Furthermore, it is known that, depending on interactions between the individual components of the mitogen‐activated protein kinase (MAPK) signaling cascades, many biological consequences, including apoptosis, are initiated. Although the importance of nitric oxide (NO) in apoptosis is controversial and likely depends on NO concentrations and cell types, this highly reactive free radical can activate the p38 MAPK signal cascade. Recent studies have suggested that thioredoxin may play an important role as an effector for some of these functions. Thioredoxin is a major redox protein for many enzymes/transcription factors and is involved in cellular functions, such as viability, activation, and proliferation. In addition to its redox regulation, thioredoxin binds directly to the apoptosis signal‐regulating kinase 1 (ASK1), thus inhibiting the activation of stress‐induced MAPK signaling cascades that lead to apoptosis. Furthermore, NO produced from newly induced neuronal NOS was reported to induce expression of thioredoxin and several other genes for preconditioning‐induced neuroprotection. Moreover, although exposure of endothelial cells to NO decreases NOS activity, this inhibition was shown to be reversed by thioredoxin. Finally, the correlation of expression of thioredoxin with endothelial NOS activity seems to suggest an important role played by this protein in perinatal changes of pulmonary artery functions. Therefore, thioredoxin may participate in the regulation of NOS activity and be involved in NO functions via multiple mechanisms.
Does Nitric Oxide Play a Role in Orofacial Pain Transmission?
Authors: YEO JIN‐FEI
Published: July 2009

Abstract: Although the synaptology, neural connectivity, and the roles played by nitric oxide (NO) and other neurotransmitters have been extensively studied in spinal pain, such information is rather scanty with respect to orofacial pain transmission. This paper presents the findings of several investigations carried out by the author and his colleagues on the roles of NO in orofacial pain transmission in male Wistar rats, using nicotinamide adenosine dinucleotide phosphate‐diaphorase (NADPH‐d) histochemistry using light and electron microscopy; and NOS immunohistochemistry and immunofluorescence using both light and confocal laser scanning microscopy. The results revealed that (1) a complicated relation existed between the nitrergic axon terminals and dendrites in the caudal part of the spinal trigeminal nucleus (cSTN); (2) the nitrergic neuronal cells bodies were not projection neurons, but rather, local circuit neurons; (3) although the thalamus projecting neurons in the cSTN did not synthesize NO, they could be modulated by NO diffused from nitrergic neurons; (4) c‐fos positive neurons in the superficial laminæ of the cSTN, detected following subcutaneous injection of 0.5 ml of 4% formalin into the left lateral face of the rats, respond to the release of glutamate through activation of N‐methyl‐d‐aspartate (NMDA), α‐amine‐3‐hydroxy‐5‐methyl‐4‐isoxazole‐propionate (AMPA) and metabotropic glutamate (mGlu) receptors expressed by these c‐fos neurons; and (5) NO might play a seemingly less important role than glutamate in neural transmission.
A Critical Assessment of the Neurodestructive and Neuroprotective Effects of Nitric Oxide
Authors: LEONG SENG‐KEE , RUAN RUN‐SHENG , ZHANG ZHI
Published: July 2009

Abstract:Whether nitric oxide is cytodestructive or cytoprotective is of obvious clinical importance. The debate on this subject in the past decade has generated much “heat and light”. This paper focuses on the actions of NO on the nervous system and reexamines the controversial issue and the contribution of the authors and their colleagues in the light of recent findings. We also report new findings, critically assesses previous experimental data, and share perspectives on this important subject.
Hypothesis: Proteasomal Dysfunction
Authors: HALLIWELL BARRY
Published: July 2009

Abstract:It is proposed that a primary mechanism leading to neuronal cell death in common neurodegenerative diseases is interference with proteasome function. This can involve genetic defects, direct inactivation of the proteasome (e.g., by reactive oxygen species), or overloading with proteins. The latter can be caused by excessive production of normal proteins or by the formation of poorly degradable proteins as a result of genetic mutations, faulty posttranslational modification, or protein modification by reactive oxygen or nitrogen species. Blockage of the proteasome leads to increased oxidative and nitrative stress, the latter apparently due to upregulation of nitric oxide synthase. Thus, agents that increase proteasome function may be generally neuroprotective, as may be NOS inhibitors. Proteasome inhibitors should be used with caution as therapeutic agents.
Nitric Oxide and Superoxide, a Deadly Cocktail
Authors: ESTÉVEZ ALVARO G. , JORDÁN JOAQUÍN
Published: July 2009

Abstract:Free radicals and oxidants may have contrasting effects on cells. Nitric oxide is a cellular messenger that acts by several mechanisms, including activation of soluble guanylate cyclase, nitrosylation of thiols, and formation of peroxynitrite. The action of nitric oxide depends on oxidative conditions in the cell. In motor neurons, nitric oxide enhances brain‐derived neurotrophic factor effects by stimulation of cGMP production. In the absence of trophic factors, nitric oxide induces motor neuron apoptosis by reacting with superoxide to form peroxynitrite. The mechanism of induction of motor neuron apoptosis by the formation of peroxynitrite is more complicated than simply the formation of a strong oxidant and it also involves decreased formation of cGMP.
Apolipoprotein‐E Allele‐Specific Regulation of Nitric Oxide Production
Authors: COLTON CAROL A. , BROWN CANDICE M. , CZAPIGA MEGGAN , VITEK MICHAEL P.
Published: July 2009

Abstract:Cognitive decline and dementia are key features of Alzheimer's disease (AD) that result from failure of neuronal function. Affected neurons demonstrate indices of nitrosative stress resulting from changes in nitric oxide (NO) mediated redox balance. Neurofibrillary tangles, a characteristic neuropathologic feature of AD, and dysfunctional neurons frequently display 3‐nitrotyrosine or other markers of nitrosative stress and immunoreactive nitric oxide synthase (NOS), suggesting that NOS‐containing neurons are affected in AD. Our previous studies showed that apolipoprotein E treatment of macrophages increased NO production. Using transgenic mouse models expressing human apoE2, apoE3, or apoE4 protein isoforms and no mouse apoE, we now report an isoform specific difference in microglial NO production. Mice expressing the apoE4 protein isoform have a greater NO production than mice expressing the apoE3 protein isoform. The supply of arginine, the sole substrate for NOS, is dependent on cationic amino acid transporters (CATs) that also demonstrate a similar pattern of apoE isoform dependency. Although arginine transport is greater in APOE4 microglia, this effect is not limited to tissue macrophages. Cortical neurons in primary culture from APOE4 transgenic mice exhibit a similar increase in arginine uptake over neurons cultured from APOE3 mice. The inappropriate levels of arginine transport and of NO in the presence of the APOE4 compared to the APOE3 gene and its products are likely to have significant impact in the CNS.
The Association Between Neuronal Nitric Oxide Synthase and Neuronal Sensitivity in the Brain After Brain Injury
Authors: LIU PHILIP K. , ROBERTSON CLAUDIA S. , VALADKA ALEX
Published: July 2009

Abstract: Injury to the central nervous system is the leading cause of disability in the United States. Neuronal death is one of the causes of disability. Among patients who survive this type of injury, various degrees of recovery in brain function are observed. The molecular basis of functional recovery is poorly understood. Clinical observations and research using experimental injury models have implicated several metabolites in the cascade of events that lead to neuronal degeneration. The levels of intracellular ATP (energy source) and pH are decreased, whereas levels of extracellular glutamate, intracellular calcium ions, and oxidative damage to RNA/DNA, protein, and lipid are increased. These initiating events can be associated with energy failure and mitochondrial dysfunction, resulting in functional or structural brain damage. The injured brain is known to express immediate early genes. Recent studies show that reactive oxygen species (ROS) cause lesions in genes from which mRNA is transcribed as part of the endogenous neuroprotective response. Although degenerating proteins and lipids may contribute to necrosis significantly after severe injury, abnormalities in genetic material, if not repaired, disturb cellular function at every level by affecting replication, transcription, and translation. These lesions include abnormal nucleic acids, known as oxidative lesions of DNA (ODLs) or of RNA (ORLs). In this review, we focus on our current understanding of the various effects of neuronal nitric oxide synthase on the formation of modified bases in DNA and RNA that are induced in the brain after injury, and how ODLs and ORLs affect cell function.
A Reassessment of the Peroxynitrite Scavenging Activity of Uric Acid
Authors: WHITEMAN M. , KETSAWATSAKUL U. , HALLIWELL B.
Published: July 2009

Abstract: Peroxynitrite is implicated in numerous human diseases. Hence, there is considerable interest in potential therapeutic peroxynitrite scavengers. It has been claimed that uric acid is a powerful peroxynitrite scavenger. We previously observed that uric acid is a powerful inhibitor of tyrosine nitration induced by peroxynitrite, but fails to prevent α1‐antiproteinase (α1‐AP) inactivation induced by peroxynitrite. However, the reactivity of peroxynitrite is significantly modified by bicarbonate and this has not been considered in evaluating the scavenging activity of uric acid and other endogenous antioxidant compounds. In the presence of bicarbonate (25 mM), the ability of uric acid, ascorbate, Trolox, and GSH to inhibit peroxynitrite‐mediated tyrosine and guanine nitration is decreased. Protection against peroxynitrite‐mediated α1‐AP inactivation is also decreased by ascorbate, Trolox, and GSH, but it is enhanced by uric acid. Bicarbonate also inhibits the ability of these compounds to prevent peroxynitrite‐mediated ABTS radical cation formation. However, the abilities of these antioxidants to prevent peroxynitrite‐mediated bleaching of pyrogallol red are enhanced by bicarbonate. These results show that physiologic concentrations of bicarbonate substantially modify the ability of uric acid to prevent peroxynitrite‐mediated reactions. This study highlights the need to use several different assays in the presence of physiologically relevant concentrations of bicarbonate when assessing compounds for peroxynitrite scavenging, in order to avoid misleading results.
Serum‐Dependence of LPS‐Induced Neurotoxicity in Rat Cortical Neurons
Authors: COOPER CYNTHIA L. , JEOHN GWANG‐HO , TOBIAS PETER , HONG JAU‐SHYONG
Published: July 2009

Abstract:Previous studies have shown that the bacterial endotoxin, lipopolysaccharide (LPS), is neurotoxic bothin vitroandin vivo. The rate of binding of LPS to a target cell is greatly enhanced by serum in general and by LPS binding protein (LBP) in particular. The purpose of the study described in this paper was to determine if microglia activation and LPS‐induced neurotoxicity is serum or LBP dependent. A murine microglial cell line, BV2, was used to assess the serum dependence of nitric oxide production and tumor necrosis factor a release in microglia. Embryonic rat cortical neuron/glia mixed cultures were used to determine the serum dependence of LPS‐induced neurotoxicity. Our results from both cell culture systems show that LPS‐induced inflammatory responses are serum dependent at lower doses of LPS and progressively become serum independent above 10 ng/ml. Purified human recombinant LBP reconstitutes the lost LPS‐induced inflammatory responses in primary and immortalized cell cultures treated with heat‐denatured serum and appears to account for the serum dependence. These data suggest that the cell surface signaling receptor for LPS at the low and high concentrations are likely to differ, consistent with the existence of a variety of LPS receptors.
Role of Nitric Oxide in Inflammation‐Mediated Neurodegeneration
Authors: LIU BIN , GAO HUI‐MING , WANG JIZ‐YUH , JEOHN GWANG‐HO , COOPER CYNTHIA L. , HONG JAU‐SHYONG
Published: July 2009

Abstract:Increasing evidence has suggested that inflammation in the brain is closely associated with the pathogenesis of several degenerative neurologic disorders, including Parkinson's disease, Alzheimer's diseases, multiple sclerosis, amyotrophic lateral sclerosis, and AIDS dementia. The hallmark of brain inflammation is the activation of glial cells, especially that of microglia that produce a variety of proinflammatory and neurotoxic factors, including cytokines, fatty acid metabolites, free radicals—such as nitric oxide (NO) and superoxide. Excessive production of NO, as a consequence of nitric oxide synthase induction in activated glia, has been attributed to participate in neurodegeneration. Using primary mixed neuron‐glia cultures and glia‐enriched cultures prepared from embryonic rodent brain tissues, we have systemically studied the relationship between the production of NO and neurodegeneration in response to stimulation by the inflammagen lipopolysaccharide. This review summarizes our recent findings on the kinetics of NO generation, the relative contribution of microglia and astrocytes to NO accumulation, the relationship between NO production and neurodegeneration, and points of intervention along the pathways associated with NO generation to achieve neuroprotection. We also describe our results relating to the effect of several opioid‐related agents on microglial activation and neuroprotection. Among these agents, the opioid receptor antagonist naloxone, especially its non‐opioid enantiomer (+)‐naloxone, promises to be of potential therapeutic value for the treatment of inflammation‐related diseases.
p38 MAP Kinase Is Involved in Lipopolysaccharide‐Induced Dopaminergic Neuronal Cell Death in Rat Mesencephalic Neuron‐Glia Cultures
Authors: JEOHN GWANG‐HO , COOPER CYNTHIA L. , WILSON BELINDA , CHANG RAYMOND C.C. , JANG KYUNG‐JIN , KIM HYOUNG‐CHUN , LIU BIN , HONG JAU‐SHYONG
Published: July 2009

Abstract:Immune stimulants, such as the bacterial endotoxin, lipopolysaccharide (LPS), the human immunodeficiency virus‐1 coat protein gp120, or β‐amyloid peptides, lead to glial activation and production of various immune mediators, such as nitric oxide (NO) and proinflammatory cytokines in the brain. These mediators appear to contribute to neuronal cell death in neurodegenerative diseases. However, the signaling pathways, which mediate the neurotoxic effect by the endotoxin, are not understood. The purpose of this study was to determine the role of mitogen‐activated protein kinase (MAPK) in LPS‐induced neurodegeneration using mesencephalic dopaminergic neuron/glia cultures. We have found that the p38 MAPK is important in LPS‐induced death of mesencephalic neurons in rat neuron‐glia mixed cultures. Upon treatment with 10 ng/ml LPS, the number of dopaminergic neurons decreased by 80% within 48 h, preceded by a significant production of NO by glia. Neuroprotection by selective inhibition of p38 MAPK activity paralleled a decrease in LPS‐induced inducible nitric oxide synthase (iNOS) expression. These events were significantly reduced by the selective p38 MAPK inhibitor, SB202190, but not by the inactive analogue SB202474. Inhibition of iNOS activity and NO production by treatment with GW274150 was also neuroprotective. Although the p38 MAPK inhibitor afforded significant neuroprotection from LPS toxicity in the neuron‐glia mixed culture, it failed to protect dopaminergic neurons from 6‐hydroxy‐dopamine‐induced toxicity, which acts directly on dopaminergic neurons by inducing hydroxyl radical formation from the mitochondria. The results suggest that p38 MAPK in glia plays a significant role in the LPS‐induced death of mesencephalic neurons through induction of nitric oxide synthase and resulting NO production.