bluuebunny/crossref_metadata_2025 huggingface dataset:
Purification of Fibrinogen and Virus Removal Using Preparative Electrophoresis
Authors: GILBERT ANDREW , EVTUSHENKO MICHAEL , NAIR HARI
Published: July 2010

Abstract: The Gradiflow is a novel, scalable preparative electrophoresis technique that uses the dual characteristics of size and charge to isolate target macro‐ and micromolecules from complex biological solutions. It does this with high resolution and in rapid time. The mild buffers are used to assist in retaining biological activity of the isolated protein. Gradiflow technology employs a sandwich of three polyacrylamide membranes configured to allow passage of macromolecules ranging in size from 10 kDa to 1,500 kDa. Fibrinogen was isolated from cryoprecipitate 1 using a single phase process. This separation was achieved within three hours with yields of 85%. Purified fibrinogen was then characterized using biophysical characterization of fibrin clot structure and compared with clots derived from a commercially available product and human plasma. Significantly, clots developed from Gradiflow fibrinogen had characteristics closer to human plasma. Viral removal characteristics of the Gradiflow were investigated by spiking the source material (cryoprecipitate 1) with canine parvovirus and testing for its presence in the isolated fibrinogen using PCR. Parvo removal was found to be greater than 4 logs and was achieved during the purification process. The Gradiflow offers the advantage of large‐scale separation of macromolecules and provides a new approach to fibrinogen separation that is quite distinct from other present‐day technologies. The technology is capable of isolating protein with high purity, recovery, and functionality in combination with the removal of viruses during the purification. Furthermore, it is capable of integrating into present production systems, significantly improving yield and functionality of target molecules.
Compulsive Drug‐Seeking Behavior and Relapse
Authors: WEISS FRIEDBERT , CICCOCIOPPO ROBERTO , PARSONS LOREN H. , KATNER SIMON , LIU XIU , ZORRILLA ERIC P. , VALDEZ GLENN R. , BEN‐SHAHAR OSNAT , ANGELETTI STEFANIA , RICHTER REGINA R.
Published: July 2010

Abstract:The development of addiction and vulnerability to relapse following withdrawal is proposed to be the result of neuroadaptive processes within the central nervous system that oppose the acute reinforcing actions of drugs of abuse. These changes lead to impairment in the mechanisms that mediate positive reinforcement and the emergence of affective changes such as anxiety, dysphoria, and depression during withdrawal. Considerable evidence exists implicating perturbations in DA and 5‐HT transmission in the nucleus accumbens—neurochemical systems that are activated by cocaine and ethanol self‐administration and deficient during withdrawal—as potential substrates for these affective changes. In addition, growing evidence suggests that enhanced CRF release in the central nucleus of the amygdala represents a mechanism underlying the anxiogenic and stress‐like consequences of withdrawal that are common to all drugs of abuse. A growing body of evidence also implicates dysregulation of the non‐neuroendocrine CRF stress system within the central nucleus of the amygdala as a common factor in the anxiogenic and aversive consequences of withdrawal from drugs of abuse. Moreover, a possible link may exist between long‐lasting abnormalities in CRF function in the CeA and vulnerability to relapse during protracted abstinence. Another presumably critical element contributing to the chronic relapsing nature of drug addiction is the learned responses to drug‐related stimuli. The long‐lasting efficacy of drug‐ and alcohol‐associated contextual stimuli in eliciting drug‐seeking behavior in animal models of relapse resembles the endurance of conditioned cue reactivity and cue‐induced cocaine craving in humans and confirms a significant role of learning factors in the long‐lasting addictive potential of cocaine. With cocaine, D1‐dependent neural mechanisms within the medial prefrontal cortex and basolateral amygdala may be important substrates for the motivating effects of drug‐related environmental stimuli. With ethanol, available data suggest a role for opioid receptors in the mediation of conditioned drug‐seeking behavior. Finally, conditioning factors (i.e., exposure to drug‐associated stimuli) and stress can interact to augment vulnerability to relapse. This finding emphasizes that it will be important to consider the simultaneous effects of multiple environmental triggers for relapse in the development of treatment and medication strategies.
Gender Differences in the Behavioral Responses to Cocaine and Amphetamine
Authors: BECKER JILL B. , MOLENDA HEATHER , HUMMER DANIEL L.
Published: July 2010

Abstract:When ovariectomized female rats receive estrogen, the response to the psychomotor stimulants amphetamine or cocaine is enhanced. Estrous cycle‐dependent differences in amphetamine‐stimulated behaviors and striatal dopamine release are also noted. Intact female rats exhibit a greater behavioral response to amphetamine on estrus than they do on other days of the cycle. Ovariectomy results in attenuation of amphetamine‐induced behavior and the striatal dopamine response to amphetamine. Physiological doses of estrogen given to ovariectomized rats reinstate both of these responses to a level comparable to that in estrous females. Furthermore, a sex difference is noted, in that females tend to exhibit a greater behavioral response to the psychomotor stimulants, and estrogen enhances this sex difference. Repeated treatment with amphetamine or cocaine produces a progressive increase in behavioral responsiveness with subsequent drug administration, a process known as sensitization. In rodents, behavioral sensitization results in increases in both frequency and duration of psychomotor behaviors such as rotational behavior, stereotyped grooming, headbobs, and forelimb movements. Interestingly, females display greater sensitization of behaviors in response to psychomotor stimulants than do males. Previous research results are summarized, and new results are presented, demonstrating that estrogen selectively enhances components of behavior that exhibit sensitization in female rats. Results also indicate gender differences in sensitization independent of gonadal hormones, suggesting that the neural systems that undergo sensitization are sexually dimorphic.
Limited Telomere Shortening in Hematopoietic Stem Cells after Transplantation
Authors: BRÜMMENDORF TIM H. , RUFER NATHALIE , BAERLOCHER GABRIELA M. , ROOSNEK EDDY , LANSDORP PETER M.
Published: July 2010

Abstract: The number of cell divisions in hematopoietic stem cells (HSCs) following transplantation of bone marrow or mobilized peripheral blood into myelo‐ablated recipients is unknown. This number is expected to depend primarily on the number of transplanted stem cells, assuming that stem cells do not differ in engraftment potential and other functional properties. In a previous study, we found that the telomere length in circulating granulocytes in normal individuals shows a biphasic decline with age, most likely reflecting age‐related changes in the turnover of HSCs. In order to study HSCs' proliferation kinetics following stem cells transplantation, we analyzed the telomere length in donor‐derived nucleated blood cells in four HLA‐matched bone marrow transplant recipients relative to comparable cells from the sibling donors. In each case, the telomeres in granulocytes were shorter in the recipient than in the donor. This difference was established in the first year post transplantation and did not change after that. The telomere length in naïve and memory T cells showed marked differences after transplantation, complicating the interpretation of telomere length data using unseparated nucleated blood cells. Interestingly, the telomere length in naïve T cells that were first observed six months post transplantation was very similar in donor and recipient pairs. Our observations are compatible with a limited number of additional cell divisions in stem cell populations after bone marrow transplantations and support the idea that different populations of stem cells contribute to short‐term myeloid and long‐term lympho‐myeloid hematopoiesis.
Mobilization of Endothelial and Hematopoietic Stem and Progenitor Cells by Adenovector‐Mediated Elevation of Serum Levels of SDF‐1, VEGF, and Angiopoietin‐1
Authors: MOORE M. A.S. , HATTORI K. , HEISSIG B. , SHIEH J.‐H. , DIAS S. , CRYSTAL R. G. , RAFII S.
Published: July 2010

Abstract: The chemokine stroma‐derived factor‐1 (SDF‐1) is produced within the bone marrow and mediates chemokinesis and chemotaxis on a variety of cell types that express the CXCR4 receptor. SDF‐1‐responsive cell types include monocytes and macrophages, B and T lymphocytes, platelets and megakaryocytes, and CD34+ cells, including both hematopoietic progenitors and stem cells. We have used intravenous injection of a replication‐incompetent adenovector expressing the SDF‐1 gene to elevate serum levels of SDF‐1 in Balb/c and SCID mice. Within 3 to 5 days there was a marked leukocytosis, predominantly involving monocytes, and a three‐fold increase in platelets. In addition, AdSDF‐1 mobilized CFU‐GM, CFU‐s, and cells with long‐term repopulating potential. We have identified a bone marrow‐derived, circulating endothelial stem cell characterized by expression of the VEGFR2 (Flk‐1/KDR). This cell exhibits a chemotactic and chemokinetic response to SDF‐1 and VEGF. We have elevated serum levels of VEGF165 using intravenous adenovector gene delivery and compared this to an adenovector expressing angiopoietin‐1 alone or in combination with VEGF. VEGF elevation was associated with rapid mobilization of hematopoietic stem and progenitor cells and a population of Flk‐1‐positive endothelial progenitors. In contrast angiopoietin induced a delayed mobilization of endothelial and hematopoietic progenitors. The combination of VEGF and angiopoietin produced a more prolonged elevation of these progenitors in the circulation with increased proliferation of capillaries and expansion of sinusoidal spaces in the marrow.
Divisional History and Pluripotency of Human Hematopoietic Stem Cells
Authors: PUNZEL MICHAEL , HO ANTHONY D.
Published: July 2010

Abstract: To maintain self‐renewal and multilineage differentiation capacity, hematopoietic stem cell (HSC) proliferation requires both symmetric and asymmetric cell divisions. We have applied a time‐lapse camera system and our single‐cell culture to correlate early replication behavior with short‐ and long‐term function. Using five‐dimensional flow cytometry to purify subpopulations of fetal liver (FLV), fetal bone marrow (FBM), umbilical cord blood (UCB), adult bone marrow (ABM), and mobilized peripheral blood (MPB), we studied the relationship between colony efficiency (CE) growth pattern and ontogenic age. The highest CE was found among HSC candidates from FLV, FBM, and UCB and the lowest from ABM. Relating the divisional behavior with functional readouts, we demonstrated that although mitotic rate, colony efficiency, and percent of asymmetric divisions all decreased with ontogenic age, the fraction of cells undergoing asymmetric divisions was consistently at 45%. After 10 days of culture, 60.6 ± 9.8% of the PKH bright cells gave rise to colonies (15.8 ± 7.8% dispersed) compared to 15.9 ± 11.1% of the PKH dim cells (2.5 ± 2.5% dispersed). In addition, the much more primitive Myeloid‐Lymphoid Initiating Cells (ML‐IC) are predominantly found in the PKH‐bright population. Thus, primitive function of individual candidate HSCs closely related to their divisional behavior.
In Vivo Dynamics of Human Stem Cell Repopulation in NOD/SCID Mice
Authors: DICK JOHN E. , GUENECHEA GUILLERMO , GAN OLGA I. , DORRELL CRAIG
Published: July 2010

Abstract: Primitive human hematopoietic cells can be assayed on the basis of their ability to repopulate immune‐deficient NOD/SCID mice and have been termed SCID repopulating cells (SRCs). The in vivo biological fate of individual SRCs can be tracked by following the unique retroviral insertion site in the progency of transduced SRCs. Distinct human SRCs were identified that differ in the proliferative and self‐renewal capacity indicating that the primitive cell compartment is functionally heterogeneous.
Phenotype and Function of Hematopoietic Stem Cells
Authors: SHARKIS SAUL J. , NEUTZEL SARA , COLLECTOR MICHAEL I.
Published: July 2010

Abstract: Using an in vivo selection technique, we can isolate individual cells that can repopulate the hematopoietic system of a lethally irradiated murine recipient. These cells rapidly acquire a CD34 phenotype in the animal. Progenitors in our long‐term chimeras are of donor type. We also have evidence that transplantation of limiting numbers (as low as a single cell) that have this long‐term repopulating ability (LTRA) can self‐renew. This is demonstrated by serial transplantation of marrow from engrafted recipients 11 months post transplant into new hosts for four additional months.
Mucin‐like Molecules as Modulators of the Survival and Proliferation of Primitive Hematopoietic Cells
Authors: SIMMONS PAUL J. , LEVESQUE JEAN‐PIERRE , HAYLOCK DAVID N.
Published: July 2010

Abstract: Current data suggest that interplay between two classes of molecules contributes to the regulation of hematopoiesis: hematopoietic growth factors, which regulate the survival, proliferation, and development of primitive hematopoietic cells and cell adhesion molecules (CAMs), which are responsible for the localization of hematopoiesis to the bone marrow (BM) and for mediating physical association between developing hematopoietic cells and marrow stromal tissue. A range of cell surface molecules representing several CAM superfamilies including integrins, selectins, the immunoglobulin gene superfamily and an emerging family of mucin‐like molecules (the sialomucins) are involved in supporting cell‐cell and cell‐extracellular matrix (ECM) interactions between primitive hematopoietic cells and the stromal cell‐mediated hematopoietic microenvironment (HM) of the bone marrow. There is abundant evidence in non‐hematopoietic tissues that CAMs are signalling molecules which participate in a range of signal transduction events important not only for regulating cell adhesion and motility, but also for cell growth and survival. Although the signalling functions of CAMs have not been studied extensively in primitive hematopoietic progenitors (HPCs), extrapolation from burgeoning data in other systems is consistent with the hypothesis that hematopoiesis within the BM is regulated by interaction between signals generated locally by CAMs and those elicited by cytokines. Evidence in support of this notion was initially provided by studies on normal HPCs demonstrating cross‐talk between members of the integrin superfamily and cytokine receptors. In this article we review recent reports that mucin‐like molecules are also signalling molecules on primitive hematopoietic cells and that the signals they deliver potently inhibit hematopoiesis.
Stem Cell Plasticity in Muscle and Bone Marrow
Authors: GOODELL MARGARET A. , JACKSON KATHYJO ANN , MAJKA SUSAN M. , MI TIEJUAN , WANG HONGYU , POCIUS JENNIFER , HARTLEY CRAIG J. , MAJESKY MARK W. , ENTMAN MARK L. , MICHAEL LLOYD H. , HIRSCHI KAREN K.
Published: July 2010

Abstract: Recent discoveries have demonstrated the extraordinary plasticity of tissue‐derived stem cells, raising fundamental questions about cell lineage relationships and suggesting the potential for novel cell‐based therapies. We have examined this phenomenon in a potential reciprocal relationship between stem cells derived from the skeletal muscle and from the bone marrow. We have discovered that cells derived from the skeletal muscle of adult mice contain a remarkable capacity for hematopoietic differentiation. Cells prepared from muscle by enzymatic digestion and 5 day in vitro culture were harvested and introduced into each of six lethally irradiated recipients together with distinguishable whole bone marrow cells. Six and twelve weeks later, all recipients showed high‐level engraftment of muscle‐derived cells representing all major adult blood lineages. The mean total contribution of muscle cell progeny to peripheral blood was 56%, indicating that the cultured muscle cells generated approximately 10‐ to 14‐fold more hematopoietic activity than whole bone marrow. Although the identity of the muscle‐derived hematopoietic stem cells is still unknown, they may be identical to muscle satellite cells, some of which lack myogenic regulators and could respond to hematopoietic signals. We have also found that stem cells in the bone marrow can contribute to cardiac muscle repair and neovascularization after ischemic injury. We transplanted highly purified bone marrow stem cells into lethally irradiated mice that subsequently were rendered ischemic by coronary artery occlusion and reperfusion. The engrafted stem cells or their progeny differentiated into cardiomyocytes and endothelial cells and contributed to the formation of functional tissue.
The Impact of ex Vivo Cytokine Stimulation on Engraftment of Primitive Hematopoietic Cells in a Non‐Human Primate Model
Authors: DUNBAR CYNTHIA E. , TAKATOKU MASAAKI , DONAHUE ROBERT E.
Published: July 2010

Abstract: The impairment of engraftment ability after ex vivo or in vivo stimulation of hematopoietic stem cells, potentially related to induction of active cell cycling, has recently been a topic of intense interest. Our group has used the non‐human primate autologous transplantation model and genetic marking to investigate a number of questions in hematopoiesis with direct relevance to human clinical applications. The issue of a potential reversible engraftment defect would have many implications for gene therapy and allogeneic or autologous transplantation. Initial in vitro studies with rhesus CD34+ cells indicated that after 4 days of stimulatory culture in stem cell factor (SCF), megakaryocyte growth and development factor (MDGF), and flt3 ligand (FLT), transfer of the cells to SCF alone on retronectin (FN) support resulted in decreased active cycling and a halt to proliferation, without a loss of viability or induction of apoptosis. We then directly compared the engraftment potential of cytokine‐stimulated cells versus those transferred to SCF on FN alone before reinfusion, SCF/G‐CSF mobilized CD34+ cells from three animals were split into two parts and transduced with either of two retroviral marking vectors for 4 days in the presence of SCF/FLT/MGDF on FN. One aliquot was cryopreserved, and the other was continued in culture without transduction for 2 days in the presence of SCF alone on FN. After total body irradiation, both aliquots were thawed and reinfused into each animal. In all animals, the level of marking from the fraction continued in culture for 2 days with SCF on FN was significantly higher than the level of marking from the aliquot transduced for 4 days without the 2‐day period in SCF alone. This approach may allow more efficient engraftment of successfully transduced or ex vivo expanded cells by avoiding active cell cycling at the time of reinfusion.
Development of a Stable Retrovirus Vector Capable of Long‐Term Expression of γ‐Globin mRNA in Mouse Erythrocytes
Authors: SABATINO DENISE E. , SEIDEL NANCY E. , CLINE AMANDA P. , ANDERSON STACIE M. , GALLAGHER PATRICK G. , BODINE DAVID M.
Published: July 2010

Abstract: Gene therapy for patients with hemoglobin disorders such has been hampered by the inability of retrovirus vectors to transfer globin genes and the locus control region (LCR) into hematopoietic stem cells without rearrangement. In addition, the expression from intact globin gene vectors has been variable in red blood cells as a result of position effects and retrovirus silencing. We hypothesized that by substituting the globin gene promoter for the promoter of another gene expressed in red blood cells, we could generate stable retrovirus vectors that would express globin at sufficient levels to treat hemoglobinopathies. Transgenic mice containing the human ankyrin (Ank) gene promoter fused to the human γ‐globin gene showed position‐independent, copy number‐dependent expression of a linked γ‐globin mRNA. We generated a “double‐copy” Ank/Aγ‐globin retrovirus vector that transferred two copies of the Ank/Aγ‐globin gene into target cells. Stable gene transfer was observed in primary primary mouse progenitor cells and long‐term repopulating hematopoietic stem cells. Expression of Ank/Aγ‐globin mRNA in mature red blood cells was approximately 8% of the level of mouse α‐globin mRNA. We conclude that this novel retrovirus vector may be valuable for treating a variety of hemoglobinopathies by gene therapy if the level of expression can be further increased.
Quinolinic Acid Accumulation During Neuroinflammation
Authors: OBRENOVITCH T. P.
Published: July 2010

Abstract:It is often proposed that quinolinic acid (QUIN) contributes to the pathophysiology of neuroinflammation because this kynurenine pathway metabolite is a selective agonist ofN‐methyl‐d‐aspartate (NMDA) receptors, and both its brain tissue and cerebrospinal fluid concentrations increase markedly with inflammation. However, whether or not the extracellular levels of QUIN reached during neuroinflammation are high enough to promote excitotoxicity, remains unclear because QUIN is a weak NMDA receptor agonist. We have addressed this issue by evaluating the extracellular concentrations of QUIN that must be reached to initiate potentially excitotoxic changes in the cerebral cortex of rats, under normal conditions, and when superimposed on another insult. We have also examined the increase in extracellular lactate associated with the perfusion of increasing concentrations of QUIN through a microdialysis probe. The extracellular EC50for induction of local depolarisation was 228 μM with QUIN alone; that is, about 30 times the levels of QUIN measured previously in immune activated brain. Furthermore, at least 20 μM extracellular QUIN needed to be reached to reduce K+induced spreading depression, an unexpected effect since spreading depression is inhibited by NMDA receptor antagonists. Our data suggest that, although synthesis of QUIN from activated microglia and invading macrophages can increase its extracellular concentration 10–100‐fold, the levels that are reached in these conditions remain far below the concentrations of QUIN that are necessary for excessive NMDA receptor activation. However, the possibility that QUIN accumulation may be a deleterious feature of neuroinflammation cannot be ruled out at this stage.
Lack of Protective Effect by Intermittent Hypoxia on MPTP‐Induced Neurotoxicity in Mice
Authors: LAI GIN‐HEUY , CHEN CHAU‐FONG , SU YU , HO LOW‐TONE , LIN ANYA MAAN‐YUH
Published: July 2010

Abstract:In contrast to acute ischemia and subsequent reperfusion that produce excess free radicals, intermittent hypoxia (IH) is reported to play an important role in upregulation of antioxidative defensive mechanisms. In the study we report here, the neuroprotective effect of IH was evaluated using intraperitoneal injection of 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) in ICR mice. Adult male ICR mice were subjected to 380 mmHg in an altitude chamber for 15 hours/day for 14 or 28 days. MPTP decreased striatal dopamine content in normoxic mice. However, IH did not significantly alter the MPTP‐induced depletion of striatal dopamine content. Furthermore, MPTP had no effect on GSH content but reduced GSH/GSSG ratio in mouse striatum. IH altered neither GSH content nor MPTP‐induced reduction in GSH/GSSG ratio. Although MPTP had no effect on striatal SOD activity in normoxic mouse, IH increased SOD activity in the saline and MPTP groups. Neither MPTP nor IH affected GPx in mouse striatum. Furthermore, in ourex vivostudy, both the autooxidation and iron induced lipid peroxidation of cortical homogenates were lower in the IH‐treated group than those of the normoxic group, indicating a reduced oxidative status after IH treatment. In conclusion, exposure to IH has been suggested to be beneficial in preventing iron‐induced oxidative injuries in biological organisms, and our data support this notion in that IH not only decreased iron‐induced lipid peroxidation but also increased antioxidative defense enzyme activity in mouse brain. Furthermore, the lack of neuroprotective effect by IH of MPTP‐induced depletion of striatal dopamine content suggests that oxidative stress may not be the only mechanism for the MPTP‐induced neurotoxicity.
The Role of Intraoperative Neurophysiology in the Protection or Documentation of Surgically Induced Injury to the Spinal Cord
Authors: DELETIS VEDRAN , SALA FRANCESCO
Published: July 2010

Abstract: Playing both neuroprotective and educational roles, introperative neurophysiology has become an intrinsic part of modern neurosurgery. In this article, we present evidence substantiating the neuroprotective role of intraoperative neurophysiology, specifically its capacity to help prevent injury to the corticospinal tracts and the dorsal columns during spinal cord injury.
Antioxidant and Antiaging Activity of N‐Acetylserotonin and Melatonin in the in Vivo Models
Authors: OXENKRUG G. , REQUINTINA P. , BACHURIN S.
Published: July 2010

Abstract: It is generally accepted that antioxidant properties of melatonin significantly contribute to its antiaging effect. Antioxidant effects of N‐acetylserotonin (NAS), a melatonin precursor and metabolite, might predict its antiaging action as well. The antiaging effect of NAS was studied in female retired breeders and male C3H mice. Both NAS and melatonin administered with drinking water prolonged life span in male animals by about 20% versus control animals (p < 0.01) but did not affect the life span of female mice. Antioxidative activity was evaluated by determining the malonaldehyde + 4‐hydroxynonenal (MDA + 4‐HNE) and cellular glutathion peroxidase (GPx) levels in male, 11‐month‐old, C57Bl/6J mice with very limited (if any) capacity to convert pineal NAS into melatonin. NAS increased the antioxidant capacity of kidney. Both NAS and melatonin (four weeks daily i.p. injections) increased the antioxidant capacity of brain as demonstrated by decreased MDA + 4‐HNE and increased GPx levels. NAS‐treated C57Bl/6J mice experienced a weight loss of 9%, whereas the saline and melatonin groups only 3%. NAS‐ and melatonin‐treated animals had healthy and luxuriant fur coats with some gray fur in the melatonin group; animals in the saline group had large areas of baldness. This study demonstrates, for the first time, the antiaging effect of NAS. This effect needs to be confirmed in animals with impaired capacity to convert NAS into melatonin.
Free Radical‐Mediated Molecular Damage
Authors: REITER RUSSEL J. , ACUÑA‐CASTROVIEJO DARIO , TAN DUN‐XIAN , BURKHARDT SUSANNE
Published: July 2010

Abstract: This review briefly summarizes the multiple actions by which melatonin reduces the damaging effects of free radicals and reactive oxygen and nitrogen species. It is well documented that melatonin protects macromolecules from oxidative damage in all subcellular compartments. This is consistent with the protection by melatonin of lipids and proteins, as well as both nuclear and mitochondrial DNA. Melatonin achieves this widespread protection by means of its ubiquitous actions as a direct free radical scavenger and an indirect antioxidant. Thus, melatonin directly scavenges a variety of free radicals and reactive species including the hydroxyl radical, hydrogen peroxide, singlet oxygen, nitric oxide, peroxynitrite anion, and peroxynitrous acid. Furthermore, melatonin stimulates a number of antioxidative enzymes including superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase. Additionally, melatonin experimentally enhances intracellular glutathione (another important antioxidant) levels by stimulating the rate‐limiting enzyme in its synthesis, γ‐glutamylcysteine synthase. Melatonin also inhibits the proxidative enzymes nitric oxide synthase and lipoxygenase. Finally, there is evidence that melatonin stabilizes cellular membranes, thereby probably helping them resist oxidative damage. Most recently, melatonin has been shown to increase the efficiency of the electron transport chain and, as a consequence, to reduce election leakage and the generation of free radicals. These multiple actions make melatonin a potentially useful agent in the treatment of neurological disorders that have oxidative damage as part of their etiological basis.
Methamphetamine‐Induced Dopaminergic Neurotoxicity: Role of Peroxynitrite and Neuroprotective Role of Antioxidants and Peroxynitrite Decomposition Catalysts
Authors: IMAM SYED Z. , EL‐YAZAL JAMAL , NEWPORT GLENN D. , ITZHAK YOSSEF , CADET JEAN L. , SLIKKER WILLIAM , ALI SYED F.
Published: July 2010

Abstract:Oxidative stress, reactive oxygen (ROS), and nitrogen (RNS) species have been known to be involved in a multitude of neurodegenerative disorders such as Parkinson's disease (PD), Alzheimer's disease (AD), and amyotrophic lateral sclerosis (ALS). Both ROS and RNS have very short half‐lives, thereby making their identification very difficult as a specific cause of neurodegeneration. Recently, we have developed a high performance liquid chromatography/electrochemical detection (HPLC/EC) method to identify 3‐nitrotyrosine (3‐NT), anin vitroandin vivobiomarker of peroxynitrite production, in cell cultures and brain to evaluate if an agent‐driven neurotoxicity is produced by the generation of peroxynitrite. We show that a single or multiple injections of methamphetamine (METH) produced a significant increase in the formation of 3‐NT in the striatum. This formation of 3‐NT correlated with the striatal dopamine depletion caused by METH administration. We also show that PC12 cells treated with METH has significantly increased formation of 3‐NT and dopamine depletion. Furthermore, we report that pretreatment with antioxidants such as selenium and melatonin can completely protect against the formation of 3‐NT and depletion of striatal dopamine. We also report that pretreatment with peroxynitrite decomposition catalysts such as 5, 10,15,20‐tetrakis(N‐methyl‐4′‐pyridyl)porphyrinato iron III (FeTMPyP) and 5, 10, 15, 20‐tetrakis (2,4,6‐trimethyl‐3,5‐sulfonatophenyl) porphinato iron III (FETPPS) significantly protect against METH‐induced 3‐NT formation and striatal dopamine depletion. We used two different approaches, pharmacological manipulation and transgenic animal models, in order to further investigate the role of peroxynitrite. We show that a selective neuronal nitric oxide synthase (nNOS) inhibitor, 7‐nitroindazole (7‐NI), significantly protect against the formation of 3‐NT as well as striatal dopamine depletion. Similar results were observed with nNOS knockout and copper zinc superoxide dismutase (CuZnSOD)‐overexpressed transgenic mice models. Finally, using the protein data bank crystal structure of tyrosine hydroxylase, we postulate the possible nitration of specific tyrosine moiety in the enzyme that can be responsible for dopaminergic neurotoxicity. Together, these data clearly support the hypothesis that the reactive nitrogen species, peroxynitrite, plays a major role in METH‐induced dopaminergic neurotoxicity and that selective antioxidants and peroxynitrite decomposition catalysts can protect against METH‐induced neurotoxicity. These antioxidants and decomposition catalysts may have therapeutic potential in the treatment of psychostimulant addictions.
Antiviral Medications Improve Cerebrovascular Perfusion in HIV+ Non‐Drug Users and HIV+ Cocaine Abusers
Authors: HERNING RONALD I. , BETTER WARREN E. , TATE KIMBERLY , CADET JEAN L.
Published: July 2010

Abstract: Antiviral medications have been useful in delaying the time course of HIV infection. Antiviral medications have also been reported to delay or reduce symptoms associated with AIDS related dementia and to improve cortical perfusion. The mechanism for this improvement is unclear. Thus, this report studies the effects of antiviral medications on cerebral blood flow velocity in HIV+ cocaine abusers, HIV+ control individuals and appropriate control individuals. Thirty‐two unmedicated HIV+ individuals (28 cocaine abusers and 4 control individuals), 22 HIV+ individuals using antiviral medications (16 cocaine abusers and 6 HIV+ control individuals), 47 HIV− cocaine abusers, and 27 control HIV− subjects were studied. Blood flow velocities were determined for the anterior and middle cerebral arteries using transcranial Doppler sonography. HIV+ individuals on antiviral medications had lower pulsatility values, suggesting decreased resistance in the cerebral blood vessels, in comparison to HIV+ individuals not taking antiviral medications. HIV+ cocaine abusers and HIV+ control individuals using antiviral medications had pulsatility values similar to HIV− control subjects. Antiviral medications appear to reduce these cerebrovascular perfusion deficits in HIV+ individuals. The antiviral medications appear to have a direct neuroprotective effect in addition to their antiviral effects. The neuroprotective role of antiviral medications requires further investigation.
Antihistamine Agent Dimebon As a Novel Neuroprotector and a Cognition Enhancer
Authors: BACHURIN S. , BUKATINA E. , LERMONTOVA N. , TKACHENKO S. , AFANASIEV A. , GRIGORIEV V. , GRIGORIEVA I. , IVANOV YU. , SABLIN S. , ZEFIROV N.
Published: July 2010

Abstract: Dimebon, launched earlier in Russia as an antihistamine drug, was evaluated as a representative of a new generation of anti‐Alzheimer's drugs that have two beneficial actions: (1) to alleviate symptoms, and (2) to prevent progression of the disease. The drug demonstrated cognition and memory‐enhancing properties in the active avoidance test in rats treated with the neurotoxin AF64A, which selectively destroys cholinergic neurons. Dimebon protected neurons in the cerebellum cell culture against the neurotoxic action of β‐amyloid fragment (Aβ25−35, EC50= 25 μM). In vitro, Dimebon displayed Ca2+‐blocking properties (IC50= 57 μM, on isolated rat ileum intestine) and pronounced anticholinesterase activity (IC50= 7.9 μM and 42 μM for butyrylcholine esterase and acetylcholine esterase, respectively). It also exhibited strong anti‐NMDA activity in the prevention of NMDA‐induced seizures in mice (EC50= 42 ± 6 mg/kg i.p.). A beneficial effect of Dimebon in the therapy of Alzheimer's disease was demonstrated in a pilot clinical trial performed in the Moscow Center of Gerontology. Fourteen patients who participated in the trial were evaluated for their state of personality and for the severity of the disease. The evaluation included orientation (space, place, time, and patient personality), memory for the past and present, life in present, speech, irritability, and so forth. During and after the eight‐week therapy with Dimebon, cognitive and self‐service functions of patients improved significantly, and psychopathic symptoms, anxiety, depression, tearfulness, and headache were substantially diminished. The results of these studies suggest Dimebon as a new candidate for the therapy of Alzheimer's‐like disorders.
Nitroxidergic Influences on Cardiovascular Control by NTS: A Link with Glutamate
Authors: TALMAN WILLIAM T. , DRAGON DEIDRE NITSCHKE , OHTA HISASHI , LIN LI‐HSIEN
Published: July 2010

Abstract: Glutamate (GLU) receptor activation, which is important in cardiovascular reflex transmission through the nucleus tractus solitarii (NTS), leads to release of nitric oxide (NO·) from central nitroxidergic neurons. Therefore, we hypothesized that GLU and NO· are linked in cardiovascular control by NTS. We first sought to determine if NO· released into NTS led to cardiovascular changes like those produced by GLU and found that the nitrosothiol S‐nitrosocysteine, but not NO· itself or other NO· donors, elicited such responses in anesthetized rats. The responses were dependent on activation of soluble guanylate cyclase but, not being affected by a scavenger of NO·, likely did not depend on release of NO· into the extracellular space. Responses to ionotropic GLU agonists in NTS, like those to S‐nitrosocysteine, were inhibited by inhibition of soluble guanylate cyclase. Inhibition of neuronal NO· synthase (nNOS) also inhibited responses to ionotropic GLU agonists. The apparent physiologic link between GLU and NO· mechanisms in NTS was further supported by anatomical studies that demonstrated frequent association between GLU‐containing nerve terminals and neurons containing nNOS. Furthermore, GLU receptors were often found on NTS neurons that were immunoreactive for nNOS. The anatomical relationships between GLU and nNOS and GLU receptors and nNOS were more pronounced in some subnuclei of NTS than in others. While seen in subnuclei that are known to receive cardiovascular afferents, the association was even more prominent in subnuclei that receive gastrointestinal afferents. These studies support a role for nitroxidergic neurons in mediating cardiovascular and other visceral reflex responses that result from release of GLU into the NTS.
Synaptic and Neurotransmitter Activation of Cardiac Vagal Neurons in the Nucleus Ambiguus
Authors: WANG JIJIANG , IRNATEN MUSTAPHA , NEFF ROBERT A. , VENKATESAN PRIYA , EVANS CORY , LOEWY ARTHUR D. , METTENLEITER THOMAS C. , MENDELOWITZ DAVID
Published: July 2010

Abstract:Cardiac vagal neurons play a critical role in the control of heart rate and cardiac function. These neurons, which are primarily located in the nucleus ambiguus (NA) and the dorsal motor nucleus of the vagus (DMNX), dominate the neural control of heart rate under normal conditions. Cardiac vagal activity is diminished and unresponsive in many disease states, while restoration of parasympathetic activity to the heart lessens ischemia and arrhythmias and decreases the risk of sudden death. Recent work has demonstrated that cardiac vagal neurons are intrinsically silent and therefore rely on synaptic input to control their firing. To date, three major synaptic inputs to cardiac vagal neurons have been identified. Stimulation of the nucleus tractus solitarius evokes a glutamatergic pathway that activates both NMDA and non‐NMDA glutamatergic postsynaptic currents in cardiac vagal neurons. Acetylcholine excites cardiac vagal neurons via three mechanisms, activating a direct ligand‐gated postsynaptic nicotinic receptor, enhancing postsynaptic non‐NMDA currents, and presynaptically by facilitating transmitter release. This enhancement by nicotine is dependent upon activation of pre‐ and postsynaptic P‐type voltage‐gated calcium channels. Additionally, there is a GABAergic innervation of cardiac vagal neurons. The transsynaptic pseudorabies virus that expresses GFP (PRV‐GFP) has been used to identify, for subsequent electrophysiologic study, neurons that project to cardiac vagal neurons. Bartha PRV‐GFP‐labeled neurons retain their normal electrophysiological properties, and the labeled baroreflex pathways that control heart rate are unaltered by the virus.
Excitatory Inputs to the RVLM in the Context of the Baroreceptor Reflex
Authors: SVED ALAN F. , ITO SATORU , MADDEN CHRISTOPHER J. , STOCKER SEAN D. , YAJIMA YOSHIHARU
Published: July 2010

Abstract:The central neural circuit mediating baroreceptor control of sympathetic vasomotor outflow involves an excitatory projection from arterial baroreceptors to nucleus tractus solitarius, an excitatory projection from nucleus tractus solitarius to the caudal ventrolateral medulla, an inhibitory projection from the caudal ventrolateral medulla to the rostral ventrolateral medulla (RVLM), and an excitatory projection from the RVLM to sympathetic preganglionic neurons in the spinal cord. For this circuit to be operational, the relevant neurons in the RVLM must be tonically active. Indeed, numerous studies have demonstrated that RVLM vasomotor neurons are tonically active; however, little is known regarding the nature of the tonic excitatory drive to these neurons. We present a model in which RVLM vasomotor neurons are tonically excited by inputs to the RVLM that can be blocked by the excitatory amino acid receptor antagonist, kynurenic acid, as well as an input from the caudal ventrolateral medulla that is not sensitive to kynurenic acid.
Central Baroreflex Resetting as a Means of Increasing and Decreasing Sympathetic Outflow and Arterial Pressure
Authors: DICARLO STEPHEN E. , BISHOP VERNON S.
Published: July 2010

Abstract: The arterial baroreflex has two important functions. First, the arterial baroreflex is a negative feedback reflex that regulates arterial pressure around a preset value called a set or operating point. Second, the arterial baroreflex also establishes the prevailing systemic arterial pressure when the operating point is reset. That is, modulating the response of barosensitive neurons in the central nervous system (CNS) establishes the operating point or prevailing systemic arterial pressure. Therefore, the operating point of the arterial baroreflex is not fixed, but is variable over a wide range of pressures and is determined by a variety of inputs from the peripheral and central nervous systems. At the onset of dynamic exercise, heart rate (HR) and sympathetic nerve activity (SNA) increase abruptly and dramatically. The initial increase in HR and SNA is mediated by central command. Central command operates by resetting the operating point of the arterial baroreflex to a higher pressure. In this situation, the operating point of the arterial baroreflex is above the prevailing arterial pressure, which elicits a blood pressure error. This error is corrected by activating SNA and inhibiting parasympathetic nerve activity, which increases cardiac output and peripheral resistance and, consequently, arterial pressure. After exercise, loss of central command and enhanced activity of the cardiopulmonary reflex resets the operating point of the arterial baroreflex to a lower pressure. In this situation, the operating point of the arterial baroreflex is below the prevailing arterial pressure, which elicits a blood pressure error. This error is corrected by inhibiting SNA, which decreases peripheral resistance and consequently arterial pressure. In these situations, central resetting of the arterial baroreflex is a means of increasing and decreasing sympathetic outflow and arterial pressure.
Familial Orthostatic Tachycardia Due to Norepinephrine Transporter Deficiency
Authors: ROBERTSON DAVID , FLATTEM NANCY , TELLIOGLU TAHIR , CARSON ROBERT , GARLAND EMILY , SHANNON JOHN R. , JORDAN JENS , JACOB GIRIS , BLAKELY RANDY D. , BIAGGIONI ITALO
Published: July 2010

Abstract:Orthostatic intolerance (OI) or postural tachycardia syndrome (POTS) is a syndrome primarily affecting young females, and is characterized by lightheadedness, palpitations, fatigue, altered mentation, and syncope primarily occurring with upright posture and being relieved by lying down. There is typically tachycardia and raised plasma norepinephrine levels on upright posture, but little or no orthostatic hypotension. The pathophysiology of OI is believed to be very heterogeneous. Most studies of the syndrome have focused on abnormalities in norepinephrine release. Here the hypothesis that abnormal norepinephrine transporter (NET) function might contribute to the pathophysiology in some patients with OI was tested. In a proband with significant orthostatic symptoms and tachycardia, disproportionately elevated plasma norepinephrine with standing, impaired systemic, and local clearance of infused tritiated norepinephrine, impaired tyramine responsiveness, and a dissociataion between stimulated plasma norepinephrine and DHPG elevation were found. Studies of NET gene structure in the proband revealed a coding mutation that converts a highly conserved transmembrane domain Ala residue to Pro. Analysis of the protein produced by the mutant cDNA in transfected cells demonstrated greater than 98% reduction in activity relative to normal. NE, DHPG/NE, and heart rate correlated with the mutant allele in this family. Conclusion: These results represent the first identification of a specific genetic defect in OI and the first disease linked to a coding alteration in a Na+/Cl−‐dependent neurotransmitter transporter. Identification of this mechanism may facilitate our understanding of genetic causes of OI and lead to the development of more effective therapeutic modalities.
Therapy of T Cell Lymphomas with Pentostatin
Authors: KURZROCK RAZELLE
Published: July 2010

Abstract: Pentostatin is a highly lymphocytotoxic agent active in hairy cell leukemia. Several studies also suggest significant activity in T cell lymphomas manifested in the skin. Herein, we will review the studies of pentostatin in these lymphomas and our most recent trial of this agent in heavily pretreated patients with cutaneous and peripheral T cell lymphomas. Overall, the data suggest that pentostatin has significant antitumor activity in these patients, with response rates ranging from 33% to over 70%. Approximately one‐third of the responses are complete. The most common side effects include granulocytopenia, nausea, and renal insufficiency. CD4 suppression occurs and may result in an increased risk of herpes zoster infection. Although prolonged remissions have been seen, most responses are short‐lived. These observations suggest that further exploration of this agent, in combination with other drugs active in T cell lymphomas, is warranted in this group of diseases.
Development of the Vertebrate Inner Ear
Authors: RINKWITZ SILKE , BOBER EVA , BAKER ROBERT
Published: July 2010

Abstract: The inner ear, also called the membranous labyrinth, contains the cochlea, which is responsible for the sense of hearing, and the vestibular apparatus, which is necessary for the sense of balance and gravity. The inner ear arises in the embryo from placodes, which are epithelial thickenings of the cranial ectoderm symmetrically located on either side of hindbrain rhombomeres 5 and 6. Placode formation in mice is first visible at the 12‐somite stage and is controlled by surrounding tissues, the paraxial mesoderm and neural ectoderm. Diffusible molecules such as growth factors play an important role in this process. The activity of several genes confers the identity to the placodal cells. Subsequent cellular proliferation processes under influences from the adjacent hindbrain cause the inner ear epithelium to invaginate and form a vesicle called the otocyst. Combinatorial expression of several genes and diffusible factors secreted from the vesicle epithelium and hindbrain control specification of distinct inner ear compartments. Transplantation studies and inner ear in vitro cultures show that each of these compartments is already committed to develop unique inner ear structures. Later developmental periods are principally characterized by intrinsic differentiation processes. In particular, sensory patches differentiate into fully functional sensory epithelia, and the semicircular canals along with the cochlear duct are elaborated and ossified.
Vestibular Abnormalities in Congenital Disorders
Authors: SANDO ISAMU , ORITA YORIHISA , MIURA MAKOTO , BALABAN CAREY D.
Published: July 2010

Abstract: This paper reviews the histopathologic features of vestibular abnormalities in congenital disorders affecting the inner ear, based upon a comprehensive literature survey and a review of cases in our temporal bone collection. The review proceeds in three systematic steps. First, we surveyed associated diseases with the major phenotypic features of congenital abnormalities of the inner ear (including the internal auditory canal and otic capsule). Second, the vestibular anomalies are examined specifically. Finally, the anomalies are discussed from a developmental perspective. Among vestibular anomalies, a hypoplastic endolymphatic duct and sac are observed most frequently. Anomalies of the semicircular canals are also often observed. From embryological and clinical viewpoints, many of these resemble the structural features from fetal stages and appear to be associated with vestibular dysfunction. It is expected that progress in genetic analysis and accumulation of temporal bone specimens with vestibular abnormalities in congenital diseases will provide crucial information not only for pathology of those diseases, but also for genetic factors that are responsible for the specific vestibular abnormalities.