bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel cell death pathway that is partially caspase dependent, but morphologically non‐apoptotic, elicited by proteasomal inhibition of rat sympathetic neurons
Authors: Lang‐Rollin Isabelle , Dermentzaki Georgia , Vekrellis Kostas , Xilouri Maria , Rideout Hardy J. , Stefanis Leonidas
Published: March 2008

Proteasomal dysfunction has been linked to neurodegeneration. Pharmacological proteasomal inhibitors may have pro‐survival or pro‐death effects in neuronal cells. We have previously found that application of such agents to mouse sympathetic neurons leads to activation of the intrinsic apoptotic pathway. We show here that in rat sympathetic neurons proteasomal inhibition leads to a form of death that is morphologically non‐apoptotic, with features of autophagy. The intrinsic apoptotic pathway is activated in a delayed fashion compared with mouse neurons, and is in part responsible for death, as evidenced by the partial protective effects of bcl‐xL and the general caspase inhibitor Boc‐aspartyl‐fluoromethylketone. Death is accompanied by induction of Bim and caspase activation, but caspase 3 activation is lacking; 3‐methyl‐adenine inhibits macroautophagy, but has a relatively small pro‐survival effect. We conclude that a complex array of pro‐ and anti‐apoptotic effects elicited by proteasomal inhibition in rat sympathetic neurons leads to partial engagement of the intrinsic apoptotic pathway and a morphologically non‐apoptotic, autophagic form of death. The species difference with mouse neurons is underscored by the fact that proteasomal inhibitors are protective against apoptosis elicited by nerve growth factor deprivation in rat, but not mouse, sympathetic neurons. The type of death described herein may be relevant to neurodegenerative diseases, where morphological evidence for apoptosis has been scant.
SP1 regulates a human SNAP‐25 gene expression
Authors: Cai Fang , Chen Bin , Zhou Weihui , Zis Odysseus , Liu Shengchun , Holt Robert A. , Honer William G. , Song Weihong
Published: March 2008

The synaptosomal‐associated protein of 25 kDa (SNAP‐25) is a pre‐synaptic plasma membrane protein. SNAP‐25 plays an important role in synaptic vesicle membrane docking and fusion, which is involved in the regulation of neurotransmitter release. SNAP‐25 has been implicated in the pathogenesis of neuropsychiatric disorders including Schizophrenia, attention‐deficit hyperactivity disorder and Alzheimer’s disease. We cloned a 1584 bp segment of the 5′ flanking region of the human SNAP‐25 gene. A series of nested deletions of the 5′ flanking region fragment were subcloned into the pGL3‐basic luciferase reporter plasmid. N2A cells were transfected with the SNAP‐25 promoter constructs and luciferase activity was measured as an indication of promoter activity. We identified a 188 bp fragment containing the transcription initiation site as the minimal region necessary for promoter activity. Several putative cis‐acting elements including SP1, hypoxia inducible factor (HIF), cAMP‐response element binding protein, T‐cell factor/lymphocyte enhancer factor 1 (TCF/LEF1), AP1 and the signal transducer and activator of transcription‐6 (STAT6) are found in the 5′ flanking region of SNAP‐25 gene. Transcriptional activation and gel shift assays showed that the human SNAP‐25 gene promoter contains functional SP1 response elements. Over‐expression of SP1 increased SNAP‐25 gene expression and inhibition of SP1‐mediated transcriptional activation reduced SNAP‐25 gene expression. These results suggest that SP1 plays an important role in regulation of the human SNAP‐25 gene expression.
Targeting epileptogenesis‐associated induction of neurogenesis by enzymatic depolysialylation of NCAM counteracts spatial learning dysfunction but fails to impact epilepsy development
Authors: Pekcec Anton , Fuest Christina , Mühlenhoff Martina , Gerardy‐Schahn Rita , Potschka Heidrun
Published: March 2008

Polysialylation is a post‐translational modification of the neural cell adhesion molecule (NCAM), which in the adult brain promotes structural changes in regions of neurogenesis and neuroplasticity. Because a variety of plastic changes including neurogenesis have been suggested to be functionally involved in the pathophysiology of epilepsies, it is of specific interest to define the impact of the polysialic acid (PSA)‐NCAM system on development of this disease and associated comorbidities. Therefore, we studied the impact of transient enzymatic depolysialylation of NCAM on the pathophysiology in an electrically induced rat post‐status epilepticus (SE) model. Loss of PSA counteracted the SE‐induced increase in neurogenesis in a significant manner. This effect of endoneuraminidase (endoN) treatment on hippocampal neurogenesis did not impact the subsequent development of spontaneous seizures. In contrast, transient lack of PSA during SE and in the early phase of epileptogenesis exhibited a cognition sparing effect as revealed in the Morris water maze paradigm. In conclusion, our data do not support a central role of neurogenesis in the development of a hyperexcitable epileptic network. However, in view of the cognition‐sparing effect, the transient modulation of the PSA‐NCAM system seems to allow beneficial long‐term disease modification, which might be mediated by the partial normalization of neurogenesis.
The Kv4.2 mediates excitatory activity‐dependent regulation of neuronal excitability in rat cortical neurons
Authors: Shen Bin , Zhou Kechun , Yang Shenglian , Xu Tianle , Wang Yizheng
Published: March 2008

Neuronal excitability can cooperate with synaptic transmission to control the information storage. This regulation of neuronal plasticity can be affected by alterations in neuronal inputs and accomplished by modulation of voltage‐dependent ion channels. In this study, we report that enhanced excitatory input negatively regulated neuronal excitability. Enhanced excitatory input by glutamate, electric field stimulation or high K+ increased transient outward K+ current, whereas did not affect the delayed rectifier K+ current in rat cultured cortical neurons. Both the voltage‐dependent K+ channel 4.2 and 4.3 subunits contributed to the increase. The increase in the K+ current density by Kv4.2 was ascribed to its cytoplasmic membrane translocation, which was mediated by NMDA type of glutamate receptor. Furthermore, enhanced excitatory input inhibited neuronal excitability. Taken together, our results suggest that excitatory neurotransmission affects neuronal excitability via the regulation of the K+ channel membrane translocation.
STAT3 activation in photoreceptors by leukemia inhibitory factor is associated with protection from light damage
Authors: Ueki Yumi , Wang Jiangang , Chollangi Srinivas , Ash John D.
Published: March 2008

Members of the interleukin‐6 cytokine family, including leukemia inhibitory factor (LIF), signal through gp130. The neuroprotective role of gp130 activation has been widely demonstrated in both CNS and PNS, but the mechanism by which this is accomplished is not well established. We investigated temporal and cell‐specific activation of signaling pathways induced by LIF in the mature mouse retina. Intravitreal injection of LIF preserved photoreceptor function and prevented photoreceptor cell death from light‐induced oxidative damage in a dose‐dependent manner (2 days post‐injection). A therapeutic dose of LIF induced rapid and sustained activation of signal transducer and activator of transcription (STAT) 3. Activated STAT3 was localized to all the retinal neurons and glial cells, including photoreceptors. Activation of extracellular signal‐regulated kinase 1 and 2 was robust but transient in Müller glial cells, and undetectable at the time of light exposure. Akt was not activated by LIF. We also show that at the time of neuroprotection, STAT3 but not extracellular signal‐regulated kinase 1 and 2 or the Akt pathways was active in LIF‐treated retinas, and activated STAT3 was clearly localized in transcriptionally active areas of photoreceptor nuclei. Our data suggest that photoreceptor protection in response to LIF can be directly mediated by activation of STAT3 in photoreceptors.
Calpain activation is involved in early caspase‐independent neurodegeneration in the hippocampus following status epilepticus
Authors: Araújo Inês M. , Gil Joana M. , Carreira Bruno P. , Mohapel Paul , Petersen Åsa , Pinheiro Paulo S. , Soulet Denis , Bahr Ben A. , Brundin Patrik , Carvalho Caetana M.
Published: March 2008

Evidence for increased calpain activity has been described in the hippocampus of rodent models of temporal lobe epilepsy. However, it is not known whether calpains are involved in the cell death that accompanies seizures. In this work, we characterized calpain activation by examining the proteolysis of calpain substrates and in parallel we followed cell death in the hippocampus of epileptic rats. Male Wistar rats were injected with kainic acid (10 mg/kg) intraperitoneally and killed 24 h later, after development of grade 5 seizures. We observed a strong Fluoro‐Jade labeling in the CA1 and CA3 areas of the hippocampus in the rats that received kainic acid, when compared with saline‐treated rats. Immunohistochemistry and western blot analysis for the calpain‐derived breakdown products of spectrin showed evidence of increased calpain activity in the same regions of the hippocampus where cell death is observed. No evidence was found for caspase activation, in the same conditions. Treatment with the calpain inhibitor MDL 28170 significantly prevented the neurodegeneration observed in CA1. Taken together, our data suggest that early calpain activation, but not caspase activation, is involved in neurotoxicity in the hippocampus after status epilepticus.
Modulation of peroxisome proliferator‐activated receptor‐α activity by N‐acetyl cysteine attenuates inhibition of oligodendrocyte development in lipopolysaccharide stimulated mixed glial cultures
Authors: Paintlia Manjeet K. , Paintlia Ajaib S. , Khan Mushfiquddin , Singh Inderjit , Singh Avtar K.
Published: March 2008

Glial cells secrete proinflammatory mediators in the brain in response to exogenous stimuli such as infection and injury. Previously, we documented that systemic maternal lipopolysaccharide (LPS)‐exposure at embryonic gestation day 18 causes oligodendrocyte (OL)‐injury/hypomyelination in the developing brain which can be attenuated by N‐acetyl cysteine (NAC; precursor of glutathione). The present study delineates the underlying mechanism of NAC‐mediated attenuation of inhibition of OL development in LPS‐stimulated mixed glial cultures. Factors released by LPS‐stimulated mixed glial cultures inhibited OL development as shown by decrease in both proliferation 3bromo‐deoxyuridine+/chondroitin sulfate proteoglycan–NG2+, hereafter BrdU+/NG+ and differentiation (O4+ and myelin basic protein+) of OL‐progenitors. Correspondingly, an impairment of peroxisomal proliferation was shown by a decrease in the level of peroxisomal proteins in the developing OLs following exposure to LPS‐conditioned media (LCM). Both NAC and WY14643, a peroxisome proliferator‐activated receptor (PPAR)‐α agonist attenuated these LCM‐induced effects in OL‐progenitors. Similar to WY14643, NAC attenuated LCM‐induced inhibition of PPAR‐α activity in developing OLs. Studies conducted with cytokines and diamide (a thiol‐depleting agent) confirmed that cytokines are active agents in LCM which may be responsible for inhibition of OL development via peroxisomal dysfunction and induction of oxidative stress. These findings were further corroborated by similar treatment of developing OLs generated from PPAR‐α(−/−) and wild‐type mice or B12 oligodendroglial cells co‐transfected with PPAR‐α small interfering RNAs/pTK‐PPREx3‐Luc plasmids. Collectively, these data provide evidence that the modulation of PPAR‐α activity, thus peroxisomal function by NAC attenuates LPS‐induced glial factors‐mediated inhibition of OL development suggesting new therapeutic interventions to prevent the devastating effects of maternal infections.
Aplysia synapse associated protein (APSAP): identification, characterization, and selective interactions with Shaker‐type potassium channels
Authors: Reissner Kathryn J. , Boyle Heather D. , Ye Xiaojing , Carew Thomas J.
Published: March 2008

The vertebrate post‐synaptic density (PSD) is a region of high molecular complexity in which dynamic protein interactions modulate receptor localization and synaptic function. Members of the membrane‐associated guanylate kinase (MAGUK) family of proteins represent a major structural and functional component of the vertebrate PSD. In order to investigate the expression and significance of orthologous PSD components associated with the Aplysia sensory neuron‐motor neuron synapse, we have cloned an Aplysia Dlg‐MAGUK protein, which we identify as Aplysia synapse associated protein (ApSAP). As revealed by western blot, RT‐PCR, and immunocytochemical analyses, ApSAP is predominantly expressed in the CNS and is located in both sensory neuron and motor neurons. The overall amino acid sequence of ApSAP is 55–61% identical to Drosophila Dlg and mammalian Dlg‐MAGUK proteins, but is more highly conserved within L27, PDZ, SH3, and guanylate kinase domains. Because these conserved domains mediate salient interactions with receptors and other PSD components of the vertebrate synapse, we performed a series of GST pull‐down assays using recombinant C‐terminal tail proteins from various Aplysia receptors and channels containing C‐terminal PDZ binding sequences. We have found that ApSAP selectively binds to an Aplysia Shaker‐type channel AKv1.1, but not to (i) NMDA receptor subunit AcNR1‐1, (ii) potassium channel AKv5.1, (iii) receptor tyrosine kinase ApTrkl, (iv) glutamate receptor ApGluR1/4, (v) glutamate receptor ApGluR2/3, or (vi) glutamate receptor ApGluR7. These findings provide preliminary information regarding the expression and interactions of Dlg‐MAGUK proteins of the Aplysia CNS, and will inform questions aimed at a functional analysis of how interactions in a protein network such as the PSD may regulate synaptic strength.
Oxidized low density lipoproteins induce a pathologic response by retinal pigmented epithelial cells
Authors: Yamada Yuko , Tian Jane , Yang Yanqin , Cutler Roy G. , Wu Tinghuai , Telljohann Richard S. , Mattson Mark P. , Handa James T.
Published: March 2008

The accumulation of apolipoprotein B100 lipoproteins in Bruch membrane is an early event thought to promote age‐related macular degeneration (AMD). Immunohistochemistry using an anti‐oxidized low density lipoprotein antibody on 10 AMD specimens showed staining in Bruch membrane including basal deposits, a marker of AMD. To determine whether retinal pigmented epithelial cells develop a pathologic phenotype after interaction with lipoproteins, ARPE‐19 cells were exposed to low density lipoproteins (LDL) or oxidized LDLs (oxLDL). Analysis using the Affymetrix U133 Plus 2.0 (Affymetrix, Inc., Santa Clara, CA, USA) gene chip showed physiological and pathological transcriptional responses after LDL and oxLDL treatment, respectively. LDL induced a down‐regulation of cholesterol biosynthesis genes while oxLDL induced transcriptional alterations in genes related to lipid metabolism, oxidative stress, inflammation and apoptosis. Electrospray mass spectrometry showed that oxLDL, but not LDL induced large cellular increases of sphingomyelin, ceramides, and cholesteryl esters. With TUNEL labeling, oxLDL caused 14.6% apoptosis compared to <1% after LDL. Addition of an inhibitor of sphingomyelin synthase inhibited this apoptosis by 41%. These data support the hypothesis that oxidized lipoproteins are one trigger for initiating early events in the pathogenesis of AMD.
Anti‐apoptotic effect of Mao‐B inhibitor PF9601N [N‐(2‐propynyl)‐2‐(5‐benzyloxy‐indolyl) methylamine] is mediated by p53 pathway inhibition in MPP+‐treated SH‐SY5Y human dopaminergic cells
Authors: Sanz Elisenda , Quintana Albert , Battaglia Valentina , Toninello Antonio , Hidalgo Juan , Ambrosio Santiago , Valoti Massimo , Marco Jose Luis , Tipton Keith F. , Unzeta Mercedes
Published: March 2008

PF9601N [N‐(2‐propynyl) 2‐(5‐benzyloxyindol) methylamine] is a non‐amphetamine type MAO‐B inhibitor that has shown neuroprotective properties in vivo using different experimental models of Parkinson’s disease. The mechanisms underlying its neuroprotective effects are poorly understood, but appear to be independent of MAO‐B inhibition. We have studied its neuroprotective properties using the human SH‐SY5Y dopaminergic cell line exposed to 1‐methyl‐4‐phenylpyridinium (MPP+), a cellular model of Parkinson’s disease. PF9601N pre‐treatment significantly reduced MPP+‐induced cell death and decreased the activation of one of the main executioner caspases, caspase‐3. MPP+ induced stabilization of transcription factor p53, which led to increased levels of this transcription factor, its nuclear translocation and transactivation of p53 response elements. PF9601N prevented this increase, thus reducing its transcriptional activity. Additional results showed that p53 may mediate its pro‐apoptotic actions through caspase‐2 under our experimental conditions. PUMA‐α may also contribute to the p53‐induced cell death. Since PF9601N significantly reduced MPP+‐induced caspase‐2 activity and PUMA‐α levels, this reduction may lead to increased cell survival. Thus, PF9601N is a novel molecule with an apparently novel mechanism of action which has a promising potential as a therapeutic agent in the treatment of neurodegenerative diseases.
A SPECTROSCOPIC INVESTIGATION OF PIGMENT AND CERAMIC SAMPLES FROM COPÁN, HONDURAS*
Authors: GOODALL R. A. , HALL J. , VIEL R. , FREDERICKS P. M.
Published: March 2008

A combination of micro‐Raman spectroscopy, micro‐infrared spectroscopy and SEM–EDX was employed to characterize decorative pigments on Classic Maya ceramics from Copán, Honduras. Variation in red paint mixtures was correlated with changing ceramic types and improvements in process and firing techniques. We have confirmed the use of specular hematite on Coner ceramics by the difference in intensities of Raman bands. Different compositions of brown paint were correlated with imported and local wares. The carbon‐iron composition of the ceramic type, Surlo Brown, was confirmed. By combining micro‐Raman analysis with micro‐ATR infrared and SEM–EDX, we have achieved a more comprehensive characterization of the paint mixtures. These spectroscopic techniques can be used non‐destructively on raw samples as a rapid confirmation of ceramic type.
Regulation and Bonding: The Sarbanes‐Oxley Act and the Flow of International Listings
Authors: PIOTROSKI JOSEPH D. , SRINIVASAN SURAJ
Published: March 2008

In this paper, we examine the economic impact of the Sarbanes‐Oxley Act (SOX) by analyzing foreign listing behavior onto U.S. and U.K. stock exchanges before and after the enactment of SOX in 2002. Using a sample of all listing events onto U.S. and U.K. exchanges from 1995–2006, we develop an exchange choice model that captures firm‐level, industry‐level, exchange‐level, and country‐level listing incentives, and test whether these listing preferences changed following the enactment of SOX. After controlling for firm characteristics and other economic determinants of these firms' exchange choice, we find that the listing preferences of large foreign firms choosing between U.S. exchanges and the London Stock Exchange's (LSE) Main Market did not change following the enactment of SOX. In contrast, we find that the likelihood of a U.S. listing among small foreign firms choosing between the NASDAQ and LSE's Alternative Investment Market decreased following the enactment of SOX. The negative effect among small firms is consistent with these marginal companies being less able to absorb the incremental costs associated with SOX compliance. The screening of smaller firms with weaker governance attributes from U.S. exchanges is consistent with the heightened governance costs imposed by SOX increasing the bonding‐related benefits of a U.S. listing.
Striking a Balance between Biodiversity Conservation and Socioeconomic Viability in the Design of Marine Protected Areas
Authors: KLEIN C. J. , CHAN A. , KIRCHER L. , CUNDIFF A. J. , GARDNER N. , HROVAT Y. , SCHOLZ A. , KENDALL B. E. , AIRAMÉ S.
Published: March 2008

Abstract:  The establishment of marine protected areas is often viewed as a conflict between conservation and fishing. We considered consumptive and nonconsumptive interests of multiple stakeholders (i.e., fishers, scuba divers, conservationists, managers, scientists) in the systematic design of a network of marine protected areas along California's central coast in the context of the Marine Life Protection Act Initiative. With advice from managers, administrators, and scientists, a representative group of stakeholders defined biodiversity conservation and socioeconomic goals that accommodated social needs and conserved marine ecosystems, consistent with legal requirements. To satisfy biodiversity goals, we targeted 11 marine habitats across 5 depth zones, areas of high species diversity, and areas containing species of special status. We minimized adverse socioeconomic impacts by minimizing negative effects on fishers. We included fine‐scale fishing data from the recreational and commercial fishing sectors across 24 fisheries. Protected areas designed with consideration of commercial and recreational fisheries reduced potential impact to the fisheries approximately 21% more than protected areas designed without consideration of fishing effort and resulted in a small increase in the total area protected (approximately 3.4%). We incorporated confidential fishing data without revealing the identity of specific fisheries or individual fishing grounds. We sited a portion of the protected areas near land parks, marine laboratories, and scientific monitoring sites to address nonconsumptive socioeconomic goals. Our results show that a stakeholder‐driven design process can use systematic conservation‐planning methods to successfully produce options for network design that satisfy multiple conservation and socioeconomic objectives.
Marine protected areas that incorporate multiple stakeholder interests without compromising biodiversity conservation goals are more likely to protect marine ecosystems.
Prevalence and Risk Factors for Helicobacter pylori Infection in Chinese Populations
Authors: Shi Ruihua , Xu Shunfu , Zhang Hongjie , Ding Yanbing , Sun Guiqian , Huang Xiayue , Chen Xiaoxing , Li Xueliang , Yan Zhigang , Zhang Guoxin
Published: March 2008

Background:  The prevalence of Helicobacter pylori is higher in developing countries. The aim of this study was to investigate the prevalence and risk factors of H. pylori infection in areas with high prevalence of gastric cancer in Jiangsu Province, China.

Methods:  A prospective epidemiologic survey of H. pylori infection was accomplished in a natural population of 1457 individuals in Xiangshui and Gaoyou counties, Jiangsu Province, China. Questionnaires and laboratory tests for H. pylori infection (13C‐urea breath test and serum IgG antibodies to H. pylori) were used and performed, respectively.

Result:  Among 1371 subjects who completed questionnaires and H. pylori detection, 851 (62%) were H. pylori positive. The prevalence reached a peak at the age of 30–40 years (67%). There was no sex difference. The annual family income level was shown to be positively correlated with the risk of H. pylori infection. The prevalence of H. pylori infection was also associated with family size, education level, and several diet‐related factors, such as the number of times cooked rice and potatoes eaten per week, and a family history of stomach diseases. Compared to nonsymptomatic individuals, people with dyspeptic symptoms (nausea, vomiting, and belching) presented a low prevalence of H. pylori infection. No association between H. pylori prevalence and smoking or drinking was found. Using multivariate logistic regression analysis, annual family income and education level were the independent predictors for H. pylori infection.

Conclusion:  High prevalence of H. pylori infection was found in areas with a high risk of gastric cancer and was related to several risk factors. The underlying mechanisms need to be further investigated.
The Role of Serum Pepsinogen and Gastrin Test for the Detection of Gastric Cancer in Korea
Authors: Kang Jung Mook , Kim Nayoung , Yoo Ji Youn , Park Young Soo , Lee Dong Ho , Kim Hyun Young , Lee Hye Seung , Choe Gheeyoung , Kim Joo Sung , Jung Hyun Chae , Song In Sung
Published: March 2008

Background and Aim:  This study was performed to determine whether serum pepsinogen (PG) and gastrin testing can be used to detect gastric cancer in Korea.

Methods:  Serum levels of PG I (sPGI) and sPGII, PG I/II ratios, and gastrin levels were measured in 1006 patients with gastroduodenal diseases including cancer. Follow‐up tests were performed 1 year after Helicobacter pylori eradication.

Results:  sPGI and sPGII levels increased and PG I/II ratios decreased in line with the severity of activity, chronic inflammation, and the presence of H. pylori (p < .01). In contrast, sPGI levels and PG I/II ratios decreased in proportion with the severity of atrophic gastritis (AG)/intestinal metaplasia (p < .01). Gastrin levels were found to be correlated with chronic inflammation negatively in the antrum but positively in the corpus. H. pylori eradication reduced sPGI, sPGII, and gastrin levels, and increased PG I/II ratios to the levels of H. pylori‐negative patients, and was found to be correlated with reductions in activity and chronic inflammation of gastritis. The sensitivity and specificity of a PG I/II ratio of ≤ 3.0 for the detection of dysplasia or cancer were 55.8–62.3% and 61%, respectively. In addition, sPGI and sPGII levels of intestinal‐type cancer were significantly lower than those of the diffuse type, respectively (p = .008 and p = .05, respectively). Gastric cancer risk was highest in the H. pylori‐positive, low PGI/II ratio (≤ 3.0) group with an odds ratio of 5.52 (confidence interval: 2.83–10.77).

Conclusion:  PG I/II ratio (≤ 3.0) was found to be a reliable marker for the detection of dysplasia or gastric cancer, especially of the intestinal type. This detection power of PG I/II ratio (≤ 3.0) significantly increased in the presence of H. pylori, and thus, provides a means of selecting those at high risk of developing gastric cancer in Korea.
Inhibition of Helicobacter pylori Infection in Humans by Lactobacillus reuteri ATCC 55730 and Effect on Eradication Therapy: A Pilot Study
Authors: Francavilla Ruggiero , Lionetti Elena , Castellaneta Stefania Paola , Magistà Anna Maria , Maurogiovanni Giovanni , Bucci Nunzia , De Canio Angela , Indrio Flavia , Cavallo Luciano , Ierardi Enzo , Miniello Vito Leonardo
Published: March 2008

Background:  Several studies report an inhibitory effect of probiotics on Helicobacter pylori.

Aim:  To test whether Lactobacillus reuteri ATCC 55730 reduces H. pylori intragastric load in vivo, decreases dyspeptic symptoms, and affects eradication rates after conventional treatment.

Materials and Methods:  In a double‐blind placebo‐controlled study, 40 H. pylori‐positive subjects were given L. reuteri once a day for 4 weeks or placebo. All underwent upper endoscopy, 13C‐urea breath test, and H. pylori stool antigen determination at entry and 13C‐urea breath test and H. pylori stool antigen (used as both qualitative and semiquantitative markers) after 4 weeks of treatment. Sequential treatment was administered subsequently to all.

Results:  In vivo, L. reuteri reduces H. pylori load as semiquantitatively assessed by both 13C‐urea breath test δ‐value and H. pylori stool antigen quantification after 4 weeks of treatment (p < .05). No change was shown in patients receiving placebo. L. reuteri administration was followed by a significant decrease in the Gastrointestinal Symptom Rating Scale as compared to pretreatment value (p < .05) that was not present in those receiving placebo (p = not significant). No difference in eradication rates was observed.

Conclusions:  L. reuteri effectively suppresses H. pylori infection in humans and decreases the occurrence of dyspeptic symptoms. Nevertheless, it does not seem to affect antibiotic therapy outcome.
Seizures following picornavirus infection
Authors: Libbey Jane E. , Kirkman Nikki J. , Smith Matthew C.P. , Tanaka Tomoko , Wilcox Karen S. , White H. Steve , Fujinami Robert S.
Published: March 2008

Summary

Purpose: We demonstrate the establishment and characterization of a novel virus infection‐induced seizure model in C57BL/6 mice.

Methods: C57BL/6 mice were infected with Theiler's murine encephalomyelitis virus (TMEV) or mock infected. Mice were followed for seizures, weight change, body temperature, motor function (righting reflex, rotorod) and neurological manifestations (inflammation [perivascular cuffing], pyknotic neurons, transforming growth factor [TGF]‐β expression).

Results: C57BL/6 mice are susceptible to seizures induced by TMEV infection. Approximately 50% of C57BL/6 mice develop transient afebrile seizures. Motor function and coordination are impaired in seized mice. Pyramidal neuron pyknosis and TGF‐β expression correlate with seizure activity in the hippocampus.

Discussion: The characterization of this model will enable the investigation of viral and immune contributions in the central nervous system to the development of seizure disorders in humans.
Conjoint Developmental Trajectories of Young Adult Substance Use
Authors: Jackson Kristina M. , Sher Kenneth J. , Schulenberg John E.
Published: March 2008

Background.  Despite the prominence of comorbidity among substances and the recent attention focused on trajectory‐based approaches to characterizing developmental change, little research in the substance use field has simultaneously considered both course and comorbidity.

Methods.  Using nationally representative panel data from the Monitoring the Future Project (MTF; n = 32,087; 56% female; 82% Caucasian), we identified developmental courses of heavy drinking, smoking, and marijuana use using 4 waves of data spanning ages 18 to 26 in a multi‐cohort young adult sample. Comorbidity was examined by cross‐classifying group membership in substance use trajectories. Finally, the extent to which risk factors (sex, race, alcohol expectancies, delinquency, sensation seeking, depressive affect, religiosity, academic achievement, and parent education) accounted for combinations of comorbidity that occurred at a rate greater than chance was examined.

Results.  For each substance, we identified 4 courses of substance use that were largely consistent with those found in the literature (chronic high use, late‐onset use, developmentally limited use, and low‐use), with a fifth moderate smoking group. Heavy drinking, smoking, and marijuana use were each highly associated, and distinct patterns of comorbidity were evident, with greatest agreement along the diagonal. All risk factors explained comorbidity to some degree, with delinquency, sensation seeking, alcohol expectancies, and religion in particular predicting combinations of comorbidity that were characterized by early onset and chronic high use.

Conclusions.  Cross‐substance trajectory concordance was high, with parallel changes in substance use over emerging adulthood. This suggests similar developmental timing of use, perhaps due to the experience of developmental transitions that have a common influence on use of different substances. Prediction of combinations of comorbidity characterized by early onset and persistently high use suggests that to some extent, individuals use multiple substances because of a common vulnerability to each, rather than directional relations among substances (e.g., cross‐tolerance, cueing).
Residual Urine as a Risk Factor for Lower Urinary Tract Infection: A 1‐Year Follow‐Up Study in Nursing Homes
Authors: Omli Ragnhild , Skotnes Liv H. , Mykletun Arnstein , Bakke August M. , Kuhry Esther
Published: March 2008

OBJECTIVES: To determine whether postvoid urine is a risk factor for the development of lower urinary tract infections (UTIs) in nursing home residents.

DESIGN: Prospective surveillance with a follow‐up period of 1 year.

SETTING: Six Norwegian nursing homes.

PARTICIPANTS: One hundred fifty nursing home residents.

METHODS: Postvoid residual (PVR) urine volumes were measured using a portable ultrasound. UTIs were registered prospectively for 1 year.

RESULTS: Ninety‐eight residents (65.3%) had a PVR less than 100 mL, and 52 (34.7%) had a PVR of 100 mL or greater. During the follow‐up period, 51 residents (34.0%) developed one or more UTIs. The prevalence of UTI in women was higher than in men (40.4% vs 19.6%; P=.02). There was no significant difference in mean PVR between residents who did and did not develop a UTI (79 vs 97 mL, P=.26). PVR of 100 mL or greater was not associated with greater risk of developing a UTI (P=.59).

CONCLUSION: High PVR is common in nursing home residents. No association between PVR and UTI was found.
PHYSIOGRAPHIC NOTES ON FEATURES IN THE MACKENZIE DELTA AREA
Authors: Fraser J.K.
Published: March 2008

Evidence is presented to show that a group of knobby hills on coalescing alluvial fans along the Richardson Mountains is landslide debris rather than glacial deposit, Associated with the debris are pingo‐like features and lenses of ground ice. A heavy layer of silt over remnant snowbanks is attributed to wind deposition.
A Finite‐State Continuous‐Time Approach for Inferring Regional Migration and Mortality Rates from Archival Tagging and Conventional Tag‐Recovery Experiments
Authors: Miller Timothy J. , Andersen Per K.
Published: March 2008

SummarySpatially structured population dynamics models are important management tools for harvested, highly mobile species and although conventional tag recovery experiments remain useful for estimation of various demographic parameters of these models, archival tagging experiments are becoming an important data source for analyzing migratory behavior of mobile marine species. We provide a likelihood‐based approach for estimating the regional migration and mortality rate parameters intrinsic to these models that may use information obtained from conventional tag recovery and archival tagging experiments. Specifically, we assume that the regional location and survival of animals through time is a finite‐state continuous‐time stochastic process. The stochastic process is the basis of probability models for observations provided by the different types of tags. Results from application to simulated tagging experiments for western Atlantic bluefin tuna show that maximum likelihood estimators based on archival tagging observations and corresponding confidence intervals perform similar to conventional tagging observations for a given number of tag releases and releasing tags in each region can improve the behavior of maximum likelihood estimators regardless of tag type. We provide an example application with Atlantic bluefin tuna released with conventional tags in 1990–1992.
A Flexible Approach to Measurement Error Correction in Case–Control Studies
Authors: Guolo A.
Published: March 2008

Summary We investigate the use of prospective likelihood methods to analyze retrospective case–control data where some of the covariates are measured with error. We show that prospective methods can be applied and the case–control sampling scheme can be ignored if one adequately models the distribution of the error‐prone covariates in the case–control sampling scheme. Indeed, subject to this, the prospective likelihood methods result in consistent estimates and information standard errors are asymptotically correct. However, the distribution of such covariates is not the same in the population and under case–control sampling, dictating the need to model the distribution flexibly. In this article, we illustrate the general principle by modeling the distribution of the continuous error‐prone covariates using the skewnormal distribution. The performance of the method is evaluated through simulation studies, which show satisfactory results in terms of bias and coverage. Finally, the method is applied to the analysis of two data sets which refer, respectively, to a cholesterol study and a study on breast cancer.
Interfacial Reactions in Glass–Ceramic‐to‐Metal Seals
Authors: Donald Ian W. , Metcalfe Brian L. , Gerrard Lee A.
Published: March 2008

During the sealing of glass–ceramics to metals, undesirable interfacial reactions may occur between constituents of the glass and diffusing metal species, and any reaction products formed may have serious consequences on the lifetime behavior of seal components. This paper reviews the factors influencing the lifetime behavior of glass–ceramic‐to‐metal systems, with particular emphasis given to the effect that such interfacial reactions can have on the resultant and longer term properties. Steps that can be taken to enhance desirable interfacial reactions and minimize those that are undesirable are highlighted. In addition, in order to aid in the understanding of complex alloy systems, it is of interest to study both the interfacial reactions and diffusion characteristics of simplified systems without the complicating issue of multiple element diffusion. Thus, a preliminary investigation is highlighted in which a lithium zinc silicate glass nucleated with P2O5 has been sealed to high‐purity Fe, Ni, and Cr metals and the resultant diffusion into the glass of each metal monitored as a function of sealing temperature and time. The data generated have been compared with information from multicomponent alloy systems and an attempt has been made to explain the differences noted.
Sc3+–Lu3+‐Doped α‐SiAlONs
Authors: Ye Feng , Liu Chunfeng , Liu Limeng , Zhou Yu , Meng Qingchang
Published: March 2008

Sc3+ and dual Sc3+–Lu3+‐doped α‐SiAlON compositions were sintered by hot pressing, and the formation behavior, microstructure, and mechanical properties were assessed. It was found that the small cation Sc3+ could not be accommodated into the α‐SiAlON structure alone. The addition of Lu2O3 in the composition induces the Sc3+ cation to enter the α‐SiAlON structure, and leads to the production of α‐SiAlON with an elongated‐grain microstructure. Transmission electron microscopy analysis shows that α‐SiAlON grains always contain an α‐Si3N4 core, implicating heterogeneous nucleation to be in present in a mixed lutetium/scandium‐doped α‐SiAlON system.
Relaxation Dynamics in Superionic Glass Nanocomposites
Authors: Bhattacharya Sanjib , Ghosh Aswini
Published: March 2008

We have studied the structural and electrical properties of several glass nanocomposite systems. The formation of nanowires, nanoparticles, and nanorods embedded in heat‐treated xAg2O–(1−x)MoO3 (x=0.2, 0.3, and 0.4) glass matrix and the growth of α‐AgI nanocrystals and ZnO nanoparticles in the 0.7AgI–0.15Ag2O–0.15(xZnO–(1−x)MoO3) (x=0.05, 0.20, and 0.30) glass matrix and α‐AgI nanocrystals in the xAgI–(1−x)(0.5Ag2O–0.5MoO3) (x=0.70, 0.75, and 0.80) glass matrices have been confirmed from X‐ray diffraction and high‐resolution transmission electron microscopic studies. We have investigated the electrical conductivity of these glass nanocomposites in a wide frequency and temperature range, and correlated them with their structures. We have analyzed the ac conductivity using a power law model. It has been observed that mobile ion concentration is independent of composition as well as temperature. It was also observed that the conductivity depends on the size of the nanoparticles grown in the host glass matrix. The scaling of the conductivity spectra reveals that the relaxation dynamics of Ag+ ions is independent of temperature and is also independent of composition at higher frequencies.
Chemical Durability of Oxide Glasses in Aqueous Solutions: A Review
Authors: Conradt Reinhard
Published: March 2008

According to common perception, glass has a chemical durability superior to most other materials. Nevertheless, when a piece of glass is exposed to an aqueous solution, corrosion takes place. In the first part of the paper, the different equilibrium‐like states related to glass dissolution are discussed. This refers to the bulk glass itself, to the aqueous solution loaded with corrosion products, to the solubility of water in glass, and to the glass surface exposed to an aqueous solution. Special attention is paid to the nature of the subsurface zone formed upon corrosion. Finally, the validity of so‐called linear free energy relationships between corrosion rates and the Gibbs energy differences of products and educts is addressed. In the second part, the mechanisms controlling the corrosion rates are discussed. Surface reaction control mechanisms leading to affinity‐based rate laws are presented, and contrasted to pore diffusion mechanisms probably explaining more accurately the slowdown of reaction rates in static corrosion scenarios.
In Situ Measurements of X‐Ray‐Induced Silver Diffusion into a Ge30Se70 Thin Film
Authors: Kovalskiy Andriy , Miller Alfred C. , Jain Himanshu , Mitkova Maria
Published: March 2008

High‐resolution X‐ray photoelectron spectroscopy is used to identify the mechanism of X‐ray‐induced Ag diffusion into Ge30Se70 chalcogenide glass thin films, which are prepared in situ to avoid oxygen contamination. From the analysis of Ge 3d, Se 3d, and Ag 3d core levels, and valence band spectra, changes in the electronic structure are determined as Ag diffuses gradually with increasing irradiation. The ternary phase based on Ge2Se6 units, which contains homopolar Ge–Ge bonds, forms when diffusion approaches equilibrium where Ag content ∼30 at.%. The formation of a Se‐rich composition is indicated in the near‐surface region at the initial stage of the process, but the previously assumed Ag2Se phase is not detected.
Textured PMN–PT and PMN–PZT
Authors: Richter Thomas , Denneler Stefan , Schuh Carsten , Suvaci Ender , Moos Ralf
Published: March 2008

A promising way to improve the performance of piezoelectric ceramics is grain orientation by templated grain growth. In this work lead‐based piezoelectric ceramics Pb(Mg1/3Nb2/3)0.68Ti0.32O3 (PMN–32PT) and Pb(Mg1/3Nb2/3)0.42(Ti0.638Zr0.362)0.58O3 (PMN–37PT–21PZ) ceramics were textured via templated grain growth process. For texturization (001)‐oriented BaTiO3 (BT) platelets (approximately 10 μm × 10 μm × 2 μm) were utilized as templates. The texturized ceramics were accomplished by aligning the templates by tape casting. The template growth into the matrix resulted in textured ceramics with Lotgering factors between 0.94 and 0.99 for both compositions. Consequences of the texture are enhanced dielectric and piezoelectric properties. Unipolar strain‐field measurements of textured ceramics showed 0.25% strain s33 at 3 kV/mm. Large signal d33* of up to 878 pm/V were determined directly from strain measurements. Compared with randomly oriented ceramics in texturized samples unipolar strain s33 and large signal d33* was enhanced by a factor of up to 1.8.
Linear Combination of Atomic Orbitals Approximation in Nanocrystalline Yittria‐Stabilized Zirconia Synthesized by Citrate–Nitrate Gel Combustion Process
Authors: Biswas Mridula , Shashidhara Kannakaje , Ojha Prasanta Kumar , Chongdar Tapas Kumar , Bandyopadhyay Nil Ratan
Published: March 2008

Nanocrystalline yittria‐stabilized zirconia (YSZ) compounds with yittria concentration varying between 8 and 12 mol% have been synthesized by gel combustion method followed by heat treatment at 550°C. The YSZs are found to posses stable face centered cubic structure at room temperature by X‐ray diffractometry. The lattice parameter ‘a’ showed an increasing trend with increasing concentration of yittria. The crystallite size estimated by Scherrer method was in the range of 7–10 nm. Band gap studies showed an increasing trend with increasing yittria concentration and are found to be consistent with respective lattice parameters following the tight binding approximation or linear combination of atomic orbitals approximation.
Microcellular Al2O3 Ceramics from Wood for Filter Applications
Authors: Rambo Carlos Renato , Andrade Tarcisio , Fey Tobias , Sieber Heino , Martinelli Antônio Eduardo , Greil Peter
Published: March 2008

Microcellular biomorphous Al2O3 was produced by Al‐vapor infiltration in pyrolyzed rattan and pine wood‐derived biocarbon preforms. At 1600°C the biocarbon preforms reacted with gaseous aluminum to form Al4C3. After oxidation in air at temperatures between 1550° and 1650°C, for 3 h, the biocarbon preforms were fully converted into α‐Al2O3. Owing to the high anisotropy of biomorphous Al2O3, the compressive strength behavior was strongly dependent on the loading direction. The compressive strength of the specimens (0.1–11 MPa) is strongly dependent on their overall porosity and their behavior could be explained using the Gibson–Ashby model. The Darcian permeability (k1), as well as the non‐Darcian permeability (k2), increased with an increase of the total porosity. The Darcian permeability of biomorphous Al2O3 was found to be in the range of 1–8 × 10−9 m2, which is in the order of magnitude of gas filters, and, therefore, suitable for several technological applications.
Synthesis of Nanosize Tin Dioxide by a Novel Liquid‐Phase Process
Authors: Zhou Yingke , Dasgupta Niladri , Virkar Anil V.
Published: March 2008

Well‐dispersed tin(IV) oxide (SnO2) nanosize crystallites were prepared by a novel liquid‐phase process using Na2SnO3 precursor of several micrometers in size. The product was characterized using powder X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and BET. The nanosize SnO2 powder formed has a narrow particle size distribution ranging between 1 and 7 nm, a very high surface area, and crystallizes in the tetragonal structure. A possible mechanism for the liquid‐phase process, which is a combined effect of coprecipitation, hydrolization, and molecular decomposition, is proposed.
Evaluation of three‐dimensional changes after sinus floor augmentation with different grafting materials
Authors: Kirmeier Robert , Payer Michael , Wehrschuetz Martin , Jakse Norbert , Platzer Susanne , Lorenzoni Martin
Published: March 2008

Objective: The aim of this retrospective investigation was to assess the dimensional stability of different grafting materials after maxillary sinus floor augmentation with computed tomography (CT) scans.

Materials and methods: Two postoperative CT scans were available from 16 patients who had undergone maxillary sinus lift procedures. The first scan was made within a few days after the surgical intervention and the second one >6 months later. A total of 25 maxillary sinuses were augmented with different materials before implant insertion by lateral antrostomy in a staged approach. The volume of bone formation was calculated using the Somaris® Sienet Magic View software.

Results: Based on volumetric measurements of the augmented domes derived from the image sections, shrinkage was about 26%. The mean of the augmented bone volume was 3.02 cm3 (1.4–5.56 cm3; SD±1.18 cm3) as determined in the first CT scan. The respective mean volume in the second CT scan amounted to 2.28 cm3 (0.92–4.46 cm3; SD±1.07 cm3).

Conclusion: Within the limits of our descriptive and analytic study, the results indicate a significant reduction of the graft volume after maxillary sinus augmentation. Further prospective studies will have to evaluate the quantitative changes of different bone graft materials for maxillary sinus augmentation procedures in order to improve long‐term implant stability.