bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of smooth muscle excitation and contraction
Authors: Sanders K. M.
Published: April 2008

Abstract  Smooth muscle cells (SMC) make up the muscular portion of the gastrointestinal (GI) tract from the distal oesophagus to the internal anal sphincter. Coordinated contractions of these cells produce the motor patterns of GI motility. Considerable progress was made during the last 20 years to understand the basic mechanisms controlling excitation‐contraction (E‐C) coupling. The smooth muscle motor is now understood in great molecular detail, and much has been learned about the mechanisms that deliver and recover Ca2+ during contractions. The majority of Ca2+ that initiates contractions comes from the external solution and is supplied by voltage‐dependent Ca2+ channels (VDCC). VDCC are regulated largely by the effects of K+ and non‐selective cation conductances (NSCC) on cell membrane potential and excitability. Ca2+ entry is supplemented by release of Ca2+ from IP3 receptor‐operated stores and by mechanisms that alter the sensitivity of the contractile apparatus to changes in cytoplasmic Ca2+. Molecular studies of the regulation of smooth muscle have been complicated by the plasticity of SMC and difficulties in culturing these cells without dramatic phenotypic changes. Major questions remain to be resolved regarding the details of E‐C coupling in human GI smooth muscles. New discoveries regarding molecular expression that give GI smooth muscle their unique properties, the phenotypic changes that occur in SMC in GI motor disorders, tissue engineering approaches to repair or replace defective muscular regions, and molecular manipulations of GI smooth muscles in animals models and in cell culture will be topics for exciting investigations in the future.
Interstitial cells of Cajal in health and disease
Authors: Farrugia G.
Published: April 2008

Abstract  The gastrointestinal tract serves the physiological function of digesting and absorbing nutrients from food and physically mixing and propelling these contents in an oral to anal direction. These functions require the coordinated interaction of several cell types, including enteric nerves, immune cells and smooth muscle. Interstitial cells of Cajal (ICC) are now recognized as another cell type that are required for the normal functioning of the gastrointestinal tract. Abnormalities in ICC numbers and networks are associated with several gastrointestinal motility disorders. This review will describe what is known about the function and role of ICC both in health and in a variety of motility disorders with a focus on unresolved issues pertaining to their role in the control of gastrointestinal motility.
Expression of CD68 in Non‐Myeloid Cell Types
Authors: Gottfried E. , Kunz‐Schughart L. A. , Weber A. , Rehli M. , Peuker A. , Müller A. , Kastenberger M. , Brockhoff G. , Andreesen R. , Kreutz M.
Published: April 2008

CD68, the human homologue of macrosialin, is commonly regarded as a selective marker for human monocytes and macrophages. Its expression is thought to be regulated by a macrophage‐specific promoter. However, several immunohistochemical studies have indicated that CD68 antibodies also react with other haematopoietic and non‐haematopoietic cell types. We investigated the expression of CD68 in various primary cells and carcinoma cell lines using immunohistochemistry, flow cytometry, Western blot analysis and qRT‐PCR. Weak but significant immunoreactivity was detected in lymphocytes and several tumour cell lines whereas staining of primary fibroblasts and endothelial cells was comparable to macrophages. The intensity of CD68 staining in individual cell types depended on the antibody clone and the fixation technique. Anti‐CD68 mAb KP1 should be used with great caution for frozen tissue sections due to its reactivity with a wide variety of cell types. Also, care should be taken when distinguishing macrophages from fibroblasts/stromal cells in paraffin sections after formalin fixation since both cell types are stained highly positive for CD68. In accordance, mRNA expression of CD68 was not only detected in macrophages and monocytes but also in fibroblasts as well as endothelial cells and tumour cells, although with a varying intensity. Cloning of full length 5′‐sequences and determination of transcription start sites shows that macrophages and fibroblasts initiate transcription within the known promoter region; however, from different start sites, indicating alternative promoter architecture in myeloid versus non‐myeloid cells. We suggest that CD68 is not a selective macrophage marker but rather a lysosomal protein that is enriched in macrophages.
Human platelet‐specific antigens frequencies in the Argentinean population
Authors: De La Vega Elena C. D. , Nogués N. , Fernández Montoya A. , Chialina S. , Blanzaco P. D. , Theiller E. , Raillon M. A. , Arancegui N. , Solis E. , Oyonarte S. , Crespo Ferrer V. , Campos Muñoz A. , Muñiz‐Díaz E.
Published: April 2008

summary The frequencies of several human platelet antigens (HPAs) vary between different populations and are a major determinant for the prevalence of HPA alloimmunization and its clinical associated entities. The aim of this study was to characterize the allele frequencies of seven HPA systems in two different ethnic groups from the Argentinean city of Rosario, the major population and a minority Amerindian group recently arrived from the north of the country, the Tobas. A total of 192 healthy unrelated individuals from blood donors and hospital staff from the Hospital Italiano Garibaldi and 27 unrelated Toba Amerindians were genotyped for HPA‐1, ‐2, ‐3, ‐4, ‐5, ‐6 and ‐15 systems by polymerase chain reaction with sequence specific primers (PCR‐SSP). The present data showed that the distribution of the HPA alleles among Argentineans from Rosario is quite similar to that reported among Europeans. The frequencies seen in Tobas, although limited by the small number of aboriginal samples studied, are similar to those reported for other Amerindians populations. Statistically significant differences were found for the genotype distribution of HPA‐1, ‐3, ‐5 and ‐15 between both groups, indicating important differences in the potential risk of HPA alloimmunization associated to transfusion and pregnancy. The study of these polymorphisms represents the first step in the elucidation of pathological conditions that are underdiagnosed in our population. It allowed us to establish a panel of characterized blood donors necessary for the serological work out and as a source for compatible platelets transfusion.
Salivary gel‐forming mucin MUC5B – a nutrient for dental plaque bacteria
Authors: Wickström C. , Svensäter G.
Published: April 2008

Introduction:  Model systems with oral bacteria from dental plaque have demonstrated that the utilization of complex glycoproteins as a food source cannot be undertaken by single species but requires concerted degradation by a multi‐species consortium, with each member contributing one or a few hydrolytic enzymes. Unlike previous studies, the aim of the present investigation was to explore the ability of fresh dental plaque to degrade salivary mucin, MUC5B, isolated by methods designed to retain intact the natural polymeric structure and physiological conformation, in an attempt to mimic the naturally occurring interaction between the oral microbiota and salivary mucins.

Methods:  Human salivary MUC5B was isolated from whole saliva by density‐gradient centrifugation and incubated with freshly isolated supragingival dental plaque with samples subjected to fluorescent staining for viability and metabolic activity. In addition, the degradation of MUC5B oligosaccharide side chains was studied using a lectin assay, recognizing three different carbohydrate epitopes commonly found on mucin oligosaccharide side chains.

Results:  The addition of purified salivary MUC5B elicited a strong metabolic response from the biofilm cells, whereas individual strains of Streptococcus oralis and Streptococcus gordonii isolated from the same plaque were not able to utilize the MUC5B. The degradation of terminal saccharide moieties on the MUC5B was demonstrated by a marked decrease in both sialic acid and fucose reactivity.

Conclusion:  These results have shown that dental plaque is capable of utilizing human salivary MUC5B as a nutrient source, a process possibly requiring the synergistic degradation of the molecule by a consortium of oral bacteria in the plaque community.
Comparison of nested polymerase chain reaction (PCR), real‐time PCR and viral culture for the detection of cytomegalovirus in subgingival samples
Authors: Botero J. E. , Vidal C. , Contreras A. , Parra B.
Published: April 2008

Introduction:  The purpose of this study was to compare nested polymerase chain reaction (PCR), real‐time PCR, and shell vial for the detection of human cytomegalovirus (HCMV) in subgingival samples in periodontitis patients.

Methods:  A group of 44 patients and 24 individuals without periodontitis were included in the study. A full periodontal examination was conducted in each subject. Gingival crevicular fluid (GCF) was collected by pocket lavage and used for viral culture (shell vial). Additional subgingival samples were obtained with paper points and used for molecular analysis. Nested PCR and real‐time PCR were used to detect and quantify HCMV. Student’s t‐test and chi‐squared test were used to compare groups. The sensitivity and specificity for the tests were calculated on 2 × 2 tables considering the nested PCR as the gold standard.

Results:  The detection of HCMV was greater using nested PCR than with either real‐time PCR or shell vial (P < 0.0001). However, the frequency detection of both molecular techniques was higher than in viral culture (P < 0.0001). Only one case of chronic periodontitis was positive by viral culture. Agreement between nested PCR and real‐time PCR was observed 47.7% and 4.1% of the time in the periodontitis and control groups, respectively. The sensitivity of real‐time PCR was 60%, compared with 2.8% for the shell vial technique.

Conclusions:  In conclusion, this study confirmed that active HCMV infection occurs in human periodontitis; however, its frequency seems to be low. In contrast, latent periodontal HCMV infection seems to be a more frequent event.
Expression and regulation of carbonic anhydrases in the marine diatom Thalassiosira pseudonana and in natural phytoplankton assemblages from Great Bay, New Jersey
Authors: McGinn Patrick J. , Morel François M. M.
Published: April 2008

blast searches of expressed sequence tag libraries have revealed putative homologs of the archetypal diatom δ‐carbonic anhydrase (CA) TWCA1 (for Thalassiosira weissflogii CA) in a broad range of eukaryotic phytoplankton including haptophytes, prasinophytes and dinoflagellates. Four putative homologs of TWCA1 are also reported and described from a search of the genomic sequence of Thalassiosira pseudonana and designated TWCATp1–4. The δ‐CA class is therefore more widely distributed in marine phytoplankton than previously thought. In particular, it is not restricted to the diatoms like the cadmium‐containing enzyme, CDCA, seems to be (ζ‐CA class). Zinc status strongly influences growth rate in marine diatoms. We observed a decrease in the specific growth rate of T. pseudonana from 2.1 to 1.3 day−1 when the unchelated Zn concentration (Zn′) was lowered from 20 to 5 pM. In the same cultures, we detected a drop in whole‐cell CA activity of about 50% in the most Zn‐limited cells that occurred simultaneously with a large downregulation of TWCATp1, TWCATp2 and CDCATp gene transcripts and protein. These three genes were also found to be strongly upregulated by low pCO2 in a manner typical of many algal CA enzymes. We have also conducted field experiments in diatom‐dominated natural phytoplankton assemblages sampled from Great Bay of the coast of New Jersey. We observed increased total CA activity in parallel with increased expression of homologous twca and cdca gene transcripts in water incubated at increasingly higher pH values. Immunoblot and transcript expression analyses demonstrated a clear upregulation of CDCA transcript and protein as incubation pH increased both in the lab and in the field indicating that this CA is expressed under a broad range of environmental conditions and not restricted to low pCO2 and low Zn.
Neurocognitive endophenotypes for bipolar disorder
Authors: Frantom Linda V , Allen Daniel N , Cross Chad L
Published: April 2008

Objectives:  Neurocognitive deficits have been proposed as vulnerability markers or endophenotypes for the development of bipolar I disorder (BD I). However, few research studies have examined whether neurocognitive deficits also exist in first‐degree relatives of individuals with BD I.

Methods:  This prospective study examined neurocognitive function in individuals with BD I, their first‐degree relatives and a normal control group using a comprehensive battery of neurocognitive tests.

Results:  Results indicated that individuals with bipolar disorder and their unaffected relatives demonstrated neuropsychological deficits in comparison to the normal control group in the domains of visuospatial/constructional abilities, executive function, visual learning and memory, and motor speed. In general, the unaffected relatives demonstrated an intermediate level of performance in comparison to the normal control and bipolar group. After adjustment for mood symptoms, significant differences were present for the visuospatial/constructional, executive function, and motor domains. Individuals with bipolar disorder also demonstrated a differential right versus left hemisphere deficit with respect to neurocognitive tasks.

Conclusions:  Results suggest that deficits on specific neuropsychological tests, most notably Digit Symbol, Block Design and Judgment of Line Orientation, may be indicative of cognitive endophenotypes for bipolar disorder. Replication studies are needed to further identify these deficits as endophenotypes for BD I.
A new accurate method for predicting lithium clearance and daily dosage requirements in adult psychiatric patients
Authors: Abou‐Auda Hisham S , Al‐Yamani Mohammad J , Abou‐Shaaban Rafiq R , Khoshhal Sahal I
Published: April 2008

Objective:  The present study aimed to derive new equations for estimating lithium clearance and daily dosage requirements needed to achieve an intended lithium serum level for adult psychiatric inpatients and outpatients.

Methods:  Data were retrospectively collected from 60 adult psychiatric patients (34 males and 26 females, aged between 18–80 years) in both inpatient and outpatient settings. All variables that might affect lithium clearance and/or lithium serum concentration were included and analyzed by stepwise multiple linear regression to produce equations describing lithium clearance and daily dosage requirements for these patients. The validation of the developed equations was performed by application to another 60 psychiatric subjects in both the inpatient and outpatient settings. The bias and accuracy of the new methods were also compared to those set forth by the empirical method and the a priori methods developed by Zetin, Pepin, Jermain and Terao and colleagues.

Results:  The following prediction equations for lithium clearance (CLLi) were obtained: CLLi (inpatients) = 0.932 + 0.185CLCr and CLLi (outpatients) = 1.021 + 0.141CLCr. The equations derived for daily dosage requirements were: daily dose (inpatients, mg) = 350.15 + 289.92 (desired lithium level, mmol/L) + 0.84 (weight, kg) − 1.76 (age, years) + 34.43 [tricyclic antidepressant (TCA), yes = 1, no = 0] + 62.1(CLCr, L/h) + 13.1 [blood urea nitrogen (BUN), mmol/L] + 40.9 (sex, male = 1, female = 0) and daily dose (outpatients, mg) = 784.92 + 530.22 (desired lithium level, mmol/L) + 8.61 (weight, kg) − 12.09 (age, years) − 11.14 (TCA, yes = 1, no = 0) − 7.63 (CLCr, L/h) − 42.62 (BUN, mmol/L) − 23.43 (sex, male = 1, female = 0). In the present method, the prediction error for clearance was 10.31% and 6.62% for inpatients and outpatients, respectively, and the prediction error for daily dosage requirements was 3.96% and 2.95% for inpatients and outpatients, respectively.

Conclusions:  Compared to previously reported methods, the present method proved to be accurate and can be safely used for the prediction of lithium clearance and daily dosage requirements in psychiatric inpatients and outpatients.
Biocontrol of Postharvest Grey Mould on Tomato by Yeasts
Authors: Dal Bello G. , Mónaco C. , Rollan M. C. , Lampugnani G. , Arteta N. , Abramoff C. , Ronco L. , Stocco M.
Published: April 2008

The fungal pathogen Botrytis cinerea causes severe rots on tomato fruit during storage and shelf life. Biological control of postharvest diseases of fruit may be an effective alternative to chemical control. Yeasts are particularly suitable for postharvest use, proving to be highly effective in reducing the incidence of fungal pathogens. Yeast fungi isolated from the surface of solanaceous plants were evaluated for their activity in reducing the postharvest decay of tomato caused by B. cinerea. Of 300 isolates, 14 strains of Rhodotorula rubra and Candida pelliculosa were found to be strongly antagonistic to the pathogen in vitro and were selected for further storage experiment. The antagonists were evaluated for their effect on the biological control of postharvest grey mould. Artificially wounded fruits were treated by means of a novel technique: small sterile discs of filter paper imbibed separately in suspensions of each yeast and the pathogen were superposed onto each wound. After 1‐week, 11 isolates were significantly effective in reducing the diameter of lesions by more than 60% compared to the control treated with B. cinerea alone. Total protection was obtained with the strain 231 of R. rubra on fruits challenged with pathogen spores. To our knowledge, R. rubra and C. pelliculosa have not been described as biocontrol agents against grey mould caused by B. cinerea. Our data demonstrate that the application of antagonistic yeasts represents a promising and environmentally friendly alternative to fungicide treatments to control postharvest grey mould of tomato.
Detection and Identification of Brenneria nigrifluens, the Causal Agent of the Shallow Bark Canker of Walnut by, PCR Amplification
Authors: Loreti S. , De Simone D. , Gallelli A.
Published: April 2008

A 1 kb DNA band from strains of Brenneria nigrifluens, as shown by amplification of their genomic DNA by polymerase chain reaction (PCR) using minisatellite primer designed on the minisatellite sequence of the M13 phage, was isolated, cloned and sequenced. Specific oligonucleotides (F1–C3) were selected into this 1 kb DNA sequence and used in a PCR assay to detect and identify strains of B. nigrifluens. Several strains of B. nigrifluens were assessed with F1–C3 primers producing a specific band of approximately 250 bp pairs in length. This target was successfully amplified from purified genomic DNA, from bacterial culture and directly from infected walnut bark tissue. No amplification was obtained when the PCR assay was performed on other plant‐pathogenic species from the following genera Brenneria, Erwinia, Agrobacterium, Pseudomonas, Ralstonia, Pectobacterium, Xanthomonas and from walnut‐associated bacteria, indicating the specificity of these primers. The PCR assay with the primers described here provides a rapid, specific and sensitive diagnostic method for B. nigrifluens and a useful tool for epidemiological studies.
Potential sources of Pythium inoculum into Greenhouse Soils with no Previous History of Cultivation
Authors: Al‐Sa’di A. M. , Drenth A. , Deadman M. L. , Al‐Said F. A. , Khan I. , Aitken E. A. B.
Published: April 2008

A study was undertaken to investigate the potential sources of Pythium inoculum in greenhouse soils. About 7% of fallow soils were found to harbour Pythium before being introduced into greenhouses. When replacing the top layer (30–60 cm) of cultivated soil in greenhouses with fallow soil, Pythium inoculum was still recovered from the bottom layer of soil left in the greenhouse. Other potential sources of Pythium were found to be potting mixtures and contaminated soil adhering to cultivation equipment, growers’ shoes and reused irrigation pipes. Pythium isolates from different sources were from two species: Pythium aphanidermatum (88%) and P. spinosum (12%). This appears to be the first report of transmission of Pythium via contaminated soil adhering to reused irrigation pipes. It also represents the first report in Oman of transmission of Pythium into greenhouses via potting mixtures and fallow soils.
The hyperthermophilic anaerobe Thermotoga Maritima is able to cope with limited amount of oxygen: insights into its defence strategies
Authors: Le Fourn Céline , Fardeau Marie‐Laure , Ollivier Bernard , Lojou Elisabeth , Dolla Alain
Published: April 2008

Thermotoga maritima, an anaerobic hyperthermophilic bacterium, was found able to grow in the presence of low concentrations of oxygen of up to 0.5% (v/v). Differential proteomics and transcripts analysis by qRT‐PCR were used to identify the defence strategies used by T. maritima to protect itself against oxygen. A flavoprotein, homologous to rubredoxin oxygen oxidoreductase was found to be overproduced when cells were cultured in oxidative conditions. The recombinant protein, produced in Escherichia coli, exhibited an oxygen reductase activity, which could account for the observed decrease in oxygen concentration during growth. The gene encoding this oxygen reductase belongs to a multicistronic unit that includes genes encoding proteins involved in exopolysaccharide biosynthesis, which may be related to a biofilm formation induced by the presence of oxygen. Enzymes involved in reactive oxygen species detoxification, iron–sulfur centre synthesis/repair and the cysteine biosynthesis pathway were also overproduced. All these enzymatic systems together contribute to the defence strategy of T. maritima against oxygen. Because of the position of T. maritima in deep branches of the phylogenetic tree, we suggest that these strategies can be considered as ancestral mechanisms first developed by anaerobic microorganisms on the early Earth to protect themselves against primary abiotic or biotic oxygen production.
Object Recognition
Authors: Grill-Spector Kalanit , Sayres Rory
Published: April 2008

Recent advancements in imaging methods and analysis approaches have provided important insights about the neural bases of object recognition. We address the potential limitations of standard functional magnetic resonance imaging (fMRI) and discuss methodological advancements, including fMRI-adaptation, pattern analyses, and high-resolution fMRI, that may be more appropriate for studying object and face representations. fMRI-adaptation and high-resolution fMRI measure responses of neural subpopulations within standard fMRI voxels, and pattern analyses examine the information in the distributed activations across voxels, which may differ from the mean response across these voxels. These methods have provided evidence for a multitude of representations across the human ventral stream that provide empirical constraints for cognitive theories of recognition.
Neuroimaging and Depression
Authors: Gotlib Ian H. , Hamilton J. Paul
Published: April 2008

Major depression is among the most debilitating, prevalent, and recurrent of all psychiatric disorders. Over the past decade, investigators have examined the neural mechanisms associated with this disorder. In this article we present an overview of neuroimaging research that has assessed the structure and functioning of the amygdala, subgenual anterior cingulate cortex, and dorsolateral prefrontal cortex in major depression. We then describe results of studies that have attempted to elucidate the nature of the relations among these brain structures. The picture that emerges from these investigations is one in which heightened activity in limbic structures that underlie the experience and expression of emotion dampens activation in dorsal cortical structures that are involved in affect regulation, reducing their ability to influence limbic activation. We conclude by highlighting unresolved issues concerning the roles of these structures in depression and their relation to specific symptoms of this disorder.
How to Exploit Diversity for Scientific Gain
Authors: Vogel Edward K. , Awh Edward
Published: April 2008

People often show considerable systematic variability in their ability to perform many different cognitive tasks. In this article, we argue that by combining an individual-differences approach with an experimental-cognitive-neuroscience approach one can often further constrain potential theories of the underlying cognitive mechanisms. In support of this proposal, we outline three basic benefits of using an individual-differences approach: validating neurophysiological measures, demonstrating associations among constructs, and demonstrating dissociations among apparently similar constructs. To illustrate these points, we describe recent work by us and other researchers that utilizes each of these techniques to address specific questions within the domain of visual working memory. It is our hope that some of these techniques for utilizing individual variability may be applied to other domains within cognitive neuroscience.
The many moods of inter‐organizational imitation: A critical review
Authors: Ordanini Andrea , Rubera Gaia , DeFillippi Robert
Published: April 2008

The management literature is paying increasing attention to the phenomenon of imitation. However, there are several gaps in understanding what drives firms’ imitative behaviors. Furthermore, a fragmented array of disciplinary perspectives has investigated imitation phenomena in the past. This paper reviews the literature on imitation and offers a unifying framework to understand what theory has said about the predictors of imitative behaviors, in terms of purposes, driving forces and target. At the end of the review, two over‐arching rationales for imitation seem to emerge: risk reduction and search for effectiveness. Next, the review distinguishes between what drives the general propensity for imitation of a firm and what makes a specific decision more likely to be imitated by the same firm. Implications and indications for future research are offered in the final section.

No single company, regardless of its determination, energy, imagination, or resources, is big enough or solvent enough to do all the productive first things that will ever occur in its industry and to always beat its competitors to all the innovations emanating from the industry.

More important, no single company can afford even to try to be first in everything in its field.

T. Levitt (1966)
Scalar Properties, Binary Judgments
Authors: ALEXANDER LARRY
Published: April 2008

abstract

In the moral realm, our deontic judgments are usually (always?) binary. An act (or omission) is either morally forbidden or morally permissible.

1

Yet the determination of an act's deontic status frequently turns on the existence of properties that are matters of degree. In what follows I shall give several examples of binary moral judgments that turn on scalar properties, and I shall claim that these examples should puzzle us. How can the existence of a property to a specific degree demarcate a boundary between an act's being morally forbidden and its not being morally forbidden? Why aren't our moral judgments of acts scalar in the way that the properties on which those judgments are based are scalar, so that acts, like states of affairs, can be morally better or worse rather than right or wrong?

I conceive of this inquiry as operating primarily within the realm of normative theory. Presumably it will give aid and comfort to consequentialists, who have no trouble mapping their binary categories onto scalar properties. For example, a straightforward act utilitarian, for whom one act out of all possible acts is morally required (and hence permissible) and all others morally forbidden, can, in theory at least, provide an answer to every one of the puzzles I raise. And, in theory, so can all other types of act and rule consequentialists. They will find nothing of interest here beyond embarrassment for their deontological adversaries.

The deontologists, however, must meet the challenges of these puzzles. And for them, the puzzles may raise not just normative questions, but questions of moral epistemology and moral ontology. Just how do we know that the act consequentialist's way of, say, trading off lives against lives is wrong? For example, do we merely intuit that taking one innocent, uninvolved person's life to save two others is wrong? Can our method of reflective equilibrium work if we have no theory by which to rationalize our intuitions? And what things in the world make it true, if it is true, that one may not make the act consequentialist's tradeoff? I do not provide any answers to these questions any more than I provide answers to the normative ones. But they surely lurk in the background.
Etazolate, a neuroprotective drug linking GABAA receptor pharmacology to amyloid precursor protein processing
Authors: Marcade Maryline , Bourdin Jérôme , Loiseau Nadia , Peillon Hélène , Rayer Aurélie , Drouin Dominique , Schweighoffer Fabien , Désiré Laurent
Published: April 2008

Pharmacological modulation of the GABAA receptor has gained increasing attention as a potential treatment for central processes affected in Alzheimer disease (AD), including neuronal survival and cognition. The proteolytic cleavage of the amyloid precursor protein (APP) through the α‐secretase pathway decreases in AD, concurrent with cognitive impairment. This APP cleavage occurs within the β‐amyloid peptide (Aβ) sequence, precluding formation of amyloidogenic peptides and leading to the release of the soluble N‐terminal APP fragment (sAPPα) which is neurotrophic and procognitive. In this study, we show that at nanomolar‐low micromolar concentrations, etazolate, a selective GABAA receptor modulator, stimulates sAPPα production in rat cortical neurons and in guinea pig brains. Etazolate (20 nM–2 μM) dose‐dependently protected rat cortical neurons against Aβ‐induced toxicity. The neuroprotective effects of etazolate were fully blocked by GABAA receptor antagonists indicating that this neuroprotection was due to GABAA receptor signalling. Baclofen, a GABAB receptor agonist failed to inhibit the Aβ‐induced neuronal death. Furthermore, both pharmacological α‐secretase pathway inhibition and sAPPα immunoneutralization approaches prevented etazolate neuroprotection against Aβ, indicating that etazolate exerts its neuroprotective effect via sAPPα induction. Our findings therefore indicate a relationship between GABAA receptor signalling, the α‐secretase pathway and neuroprotection, documenting a new therapeutic approach for AD treatment.
Modulation of taste sensitivity by GLP‐1 signaling
Authors: Shin Yu‐Kyong , Martin Bronwen , Golden Erin , Dotson Cedrick D. , Maudsley Stuart , Kim Wook , Jang Hyeung‐Jin , Mattson Mark P. , Drucker Daniel J. , Egan Josephine M. , Munger Steven D.
Published: April 2008

In many sensory systems, stimulus sensitivity is dynamically modulated through mechanisms of peripheral adaptation, efferent input, or hormonal action. In this way, responses to sensory stimuli can be optimized in the context of both the environment and the physiological state of the animal. Although the gustatory system critically influences food preference, food intake and metabolic homeostasis, the mechanisms for modulating taste sensitivity are poorly understood. In this study, we report that glucagon‐like peptide‐1 (GLP‐1) signaling in taste buds modulates taste sensitivity in behaving mice. We find that GLP‐1 is produced in two distinct subsets of mammalian taste cells, while the GLP‐1 receptor is expressed on adjacent intragemmal afferent nerve fibers. GLP‐1 receptor knockout mice show dramatically reduced taste responses to sweeteners in behavioral assays, indicating that GLP‐1 signaling normally acts to maintain or enhance sweet taste sensitivity. A modest increase in citric acid taste sensitivity in these knockout mice suggests GLP‐1 signaling may modulate sour taste, as well. Together, these findings suggest a novel paracrine mechanism for the regulation of taste function.
Characterization of PINK1 processing, stability, and subcellular localization
Authors: Lin William , Kang Un Jung
Published: April 2008

Mutations found in PTEN‐induced putative kinase 1 (PINK1), a putative mitochondrial serine/threonine kinase of unknown function, have been linked to autosomal recessive Parkinson’s disease. It is suggested that mutations can cause a loss of PINK1 kinase activity and eventually lead to mitochondrial dysfunction. In this report, we examined the subcellular localization of PINK1 and the dynamic kinetics of PINK1 processing and degradation. We also identified cytosolic chaperone heat‐shock protein 90 (Hsp90) as an interacting protein of PINK1 by PINK1 co‐immunoprecipitation. Immunofluorescence of PINK1 protein and mitochondrial isolation show that the precursor form of PINK1 translocates to the mitochondria and is processed into two cleaved forms of PINK1, which in turn localize more to the cytosolic than mitochondrial fraction. The cleavage does not occur and the uncleaved precursor stays associated with the mitochondria when the mitochondrial membrane potential is disrupted. Metabolic labeling analyses show that the PINK1 processing is rapid and the levels of cleaved forms are tightly regulated. Furthermore, cleaved forms of PINK1 are stabilized by Hsp90 interaction as the loss of Hsp90 activity decreases PINK1 level after mitochondrial processing. Lastly, we also find that cleaved forms of PINK1 are degraded by the proteasome, which is uncommon for mitochondrial proteins. Our findings support a dual subcellular localization, implying that PINK1 can reside in the mitochondria and the cytosol. This raises intriguing functional roles that bridge these two cellular compartments.
A novel intracellular role of matrix metalloproteinase‐3 during apoptosis of dopaminergic cells
Authors: Choi Dong Hee , Kim Eun‐Mee , Son Hyo Jin , Joh Tong H. , Kim Yoon Seong , Kim Donghou , Flint Beal M. , Hwang Onyou
Published: April 2008

We have previously demonstrated that the active form of matrix metalloproteinase‐3 (actMMP‐3) is released from dopamine(DA)rgic neurons undergoing apoptosis. Herein, whether actMMP‐3 might be generated intracellularly, and if so, whether it is involved in apoptosis of DArgic neurons itself was investigated in primary cultured DArgic neurons of wild‐type, MMP‐3 knockout animals, and CATH.a cells. During apoptosis, gene expression of MMP‐3 is induced, specifically among the various classes of MMPs, generating the proform (55 kDa) which is subsequently cleaved to the catalytically active actMMP‐3 (48 kDa) involving a serine protease. Intracellular actMMP‐3 activity is directly linked to apoptotic signaling in DArgic cells: (i) Pharmacologic inhibition of enzymatic activity, repression of gene expression by siRNA, and gene deficiency all lead to protection; (ii) pharmacologic inhibition causes attenuation of DNA fragmentation and caspase 3 activation, the indices of apoptosis; and (iii) inhibition of the pro‐apoptotic enzyme c‐JunN‐terminal protein kinase leads to repression of MMP‐3 induction. Under the cell stress condition, MMP‐3 is released as actMMP‐3 rather than the proform (proMMP‐3), and catalytically active MMP‐3 added to the medium does not cause cell death. Thus, actMMP‐3 seems to have a novel intracellular role in apoptotic DArgic cells and this finding provides an insight into the pathogenesis of Parkinson’s disease.
Adenosine A1 receptors inhibit GABAergic transmission in rat tuberomammillary nucleus neurons
Authors: Yum Do‐Seop , Cho Jin‐Hwa , Choi In‐Sun , Nakamura Michiko , Lee Jong‐Ju , Lee Maan‐Gee , Choi Byung‐Ju , Choi Jae‐Kap , Jang Il‐Sung
Published: April 2008

The adenosinergic modulation of GABAergic spontaneous miniature inhibitory postsynaptic currents (mIPSCs) was investigated in mechanically dissociated rat tuberomammillary nucleus (TMN) neurons using a conventional whole‐cell patch clamp technique. Adenosine (100 μM) reversibly decreased mIPSC frequency without affecting the current amplitude, indicating that adenosine acts presynaptically to decrease the probability of spontaneous GABA release. The adenosine action on GABAergic mIPSC frequency was completely blocked by 1 μM DPCPX, a selective A1 receptor antagonist, and mimicked by 1 μM CPA, a selective A1 receptor agonist. This suggests that presynaptic A1 receptors were responsible for the adenosine‐mediated inhibition of GABAergic mIPSC frequency. CPA still decreased GABAergic mIPSC frequency even either in the presence of 200 μM Cd2+, a general voltage‐dependent Ca2+ channel blocker, or in the Ca2+‐free external solution. However, the inhibitory effect of CPA on GABAergic mIPSC frequency was completely occluded by 1 mM Ba2+, a G‐protein coupled inwardly rectifying K+ (GIRK) channel blocker. In addition, the CPA‐induced decrease in mIPSC frequency was completely occluded by either 100 μM SQ22536, an adenylyl cyclase (AC) inhibitor, or 1 μM KT5720, a specific protein kinase A (PKA) inhibitor. The results suggest that the activation of presynaptic A1 receptors decreases spontaneous GABAergic transmission onto TMN neurons via the modulation of GIRK channels as well as the AC/cAMP/PKA signal transduction pathway. This adenosine A1 receptor‐mediated modulation of GABAergic transmission onto TMN neurons may play an important role in the fine modulation of the excitability of TMN histaminergic neurons as well as the regulation of sleep‐wakefulness.
Haplotype Analysis Confirms the Association Between the HCRTR2 Gene and Cluster Headache
Authors: Rainero Innocenzo , Gallone Salvatore , Rubino Elisa , Ponzo Paola , Valfre Walter , Binello Eleonora , Fenoglio Pierpaola , Gentile Salvatore , Anoaica Mihaela , Gasparini Mauro , Pinessi Lorenzo
Published: April 2008

Background.— Several studies suggested that genetic factors play a role in cluster headache (CH) susceptibility. We found a significant association between the 1246 G>A polymorphism of the hypocretin receptor‐2 (HCRTR2) gene and the disease. This association was confirmed in a large study from Germany but was not replicated in a dataset of CH patients from Northern Europe.

Objective.— The purpose of this study was to further evaluate the association between CH and the HCRTR2 gene using new polymorphisms, estimating the frequency of different gene haplotypes, searching for gene mutations, and evaluating the effects of the examined polymorphisms on hypocretin binding sites.

Methods.— We genotyped 109 CH patients and 211 healthy controls for 5 new polymorphisms of the HCRTR2 gene and we inferred different gene haplotypes. Complete HCRTR2 sequencing was undertaken for 11 independent CH patients, 5 of whom had a positive family history. The effects of the 1246 G>A polymorphism on the hypocretin binding sites were evaluated using different computer‐assisted analyses.

Results.— Three new polymorphisms of the HCRTR2 gene resulted significantly associated with CH. The GTAAGG haplotype resulted more frequent in cases than in controls (OR: 3.68; 95% CI: 1.85‐7.67). No point mutation of the HCRTR2 gene was found. Binding analyses showed that the 1246 G>A polymorphism (substitution of valine at position 308 by isoleucine) has no effect on the hypocretin binding sites but could influence the dimerization process of the receptor.

Conclusion.— Our data confirm previous studies suggesting that the HCRTR2 gene or a linked locus significantly modulates the risk for CH. In addition, we suggest that the V308I substitution of the HCRTR2 may interfere with the dimerization process of the receptor, thereby influencing its functional activity.
Docking is not a Prerequisite but a Temporal Constraint for Fusion of Secretory Granules
Authors: Kasai Kazuo , Fujita Takuji , Gomi Hiroshi , Izumi Tetsuro
Published: April 2008

We examined secretory granule dynamics using total internal reflection fluorescence microscopy in normal pancreatic β cells and their mutants devoid of Rab27a and/or its effector, granuphilin, which play critical roles in the docking and recruitment of insulin granules to the plasma membrane. In the early phase of glucose stimulation in wild‐type cells, we observed marked fusion of granules recruited from a relatively distant area, in parallel with that from granules located underneath the plasma membrane. Furthermore, despite a lack of granules directly attached to the plasma membrane, both spontaneous and evoked fusion was increased in granuphilin‐null cells. In addition to these granuphilin‐null phenotypes, Rab27a/granuphilin doubly deficient cells showed the decreases in granules located next to the docked area and in fusion from granules near the plasma membrane in the early phase of glucose‐stimulated secretion, similar to Rab27a‐mutated cells. Thus, the two proteins play nonoverlapping roles in insulin exocytosis: granuphilin acts on the granules underneath the plasma membrane, whereas Rab27a acts on those in a more distal area. These findings demonstrate that, in contrast to our conventional understanding, stable attachment of secretory granules to the plasma membrane is not prerequisite but temporally inhibitory for both spontaneous and evoked fusion.
Changes in Support From Confidants, Children, and Friends Following Widowhood
Authors: Ha Jung‐Hwa
Published: April 2008

This paper examines the extent to which widowhood affects changes in (a) the availability of a confidant, (b) emotional support from children, and (c) emotional support from friends/relatives both 6 and 18 months after spousal loss. Analyses are based on data from the Changing Lives of Older Couples, a prospective study of 1,532 married individuals aged 65 and older. Compared to married persons, widowed persons are less likely to have a confidant, yet they receive greater support from children, friends, and relatives, controlling for support prior to widowhood. The findings suggest that, although close social relationships may remain stable in the course of normal aging, stressful events such as widowhood may bring forth both losses and gains in social support.
Relative Spousal Earnings and Marital Happiness Among African American and White Women
Authors: Furdyna Holly E. , Tucker M. Belinda , James Angela D.
Published: April 2008

The distinctive economic histories of African American and White wives suggest that involvement in household income production holds contextually situated unique meanings for these groups. Yet research has not addressed racial differences in the effects of relative earnings on marital well‐being. Surveying 431 employed wives in 21 U.S. cities, we found that wife‐to‐husband income ratio and marital happiness were negatively associated when women held traditional values, but in racially distinct ways. Among White women only, a negative association between income ratio and marital happiness was reversed when financial need was reported. Findings are discussed in terms of variability in the meaning of wives’ earnings as a function of situational, historical, and sociocultural dynamics.
Interparental Incongruence in Differential Treatment of Adolescent Siblings: Links With Marital Quality
Authors: Kan Marni L. , McHale Susan M. , Crouter Ann C.
Published: April 2008

This study examined longitudinal links between incongruence in mothers’ versus fathers’ differential treatment of adolescent‐age siblings and parents’ marital quality. Multilevel models including 200 families, over four waves, spaced across 6 years tested whether youth perceptions of incongruence in differential intimacy and conflict predicted trajectories of mothers’ and fathers’ reports of marital conflict and satisfaction and vice versa. Analyses showed that changes in interparental incongruence covaried longitudinally with changes in marital quality and that these linkages became stronger over time. These results extend previous cross‐sectional research with younger children and are consistent with theories regarding family alliances and coparenting. Discussion focuses on the reciprocal relations between incongruence in parenting and marital quality as an important aspect of family systems.
Familial Factors Associated With the Use of Multiple Child‐Care Arrangements
Authors: Morrissey Taryn W.
Published: April 2008

This study examined the use of multiple, concurrent, nonparental child‐care arrangements among children under 5 with employed mothers in the NICHD Study of Early Child Care and Youth Development (N= 759). Older children, those primarily cared for in informal child care, those living in cohabitating or single‐parent households, and those whose mothers were employed for 40 or fewer hours per week were likely to be in multiple arrangements. Higher quality primary child‐care and lower maternal satisfaction with primary care predicted the subsequent use of multiple arrangements. Little support for income differences in selection into multiple arrangements was found. Findings highlight the importance of child‐care characteristics and structure in child‐care choice. Policy implications are discussed.
Human MHC architecture and evolution: implications for disease association studies
Authors: Traherne J. A.
Published: April 2008

Major histocompatibility complex (MHC) variation is a key determinant of susceptibility and resistance to a large number of infectious, autoimmune and other diseases. Identification of the MHC variants conferring susceptibility to disease is problematic, due to high levels of variation and linkage disequilibrium. Recent cataloguing and analysis of variation over the complete MHC has facilitated localization of susceptibility loci for autoimmune diseases, and provided insight into the MHC's evolution. This review considers how the unusual genetic characteristics of the MHC impact on strategies to identify variants causing, or contributing to, disease phenotypes. It also considers the MHC in relation to novel mechanisms influencing gene function and regulation, such as epistasis, epigenetics and microRNAs. These developments, along with recent technological advances, shed light on genetic association in complex disease.
Improved Follow‐Up Care of Hypertensive Patients By a Nurse Practitioner in a Rural Clinic*
Authors: McClellan William M. , Craxton Linda Connell
Published: April 2008

The usefulness of nurse practitioners in the care of hypertension has been demonstrated in a variety of settings. In a randomized prospective comparison between physicians and nurse practitioner care, observations are extended to rural ambulatory hypertensives. Data indicate that for patients who remain actively in follow‐up, blood pressure control was the same when treated by either physicians or the nurse practitioner. However, patients treated by the nurse practitioner had a significantly better follow‐up adherence rate than did those treated by physicians. The data presented support the use of nurse practitioners in the care of hypertension, particularly in rural populations where a need for intermediate level practitioners is likely to persist despite an expanding supply of physicians.
Establishing a Quality Laboratory In a Rural Medical Practice
Authors: Chick Ernest W. , Walker Robert
Published: April 2008

Laboratory services are not as readily accessible to the rural medical practitioner as to the practitioner in an urban setting. Thus, the office laboratory in a rural medical practice, by necessity, becomes an integral component of that practice. In addition to procedural methodologies, the rural physician must give consideration to the types of laboratory services needed, the requirements for test performance, the factors influencing test costs, the establishment of charges, the necessary protocols and paperwork, the arrangements of the laboratory work area, and the requisite quality control to insure that the office laboratory functions expediently and cost‐accountable.