bluuebunny/crossref_metadata_2025 huggingface dataset:
Absence of metabotropic glutamate receptor-mediated plasticity in the neocortex of fragile X mice
Authors: Wilson Brian M. , Cox Charles L.
Published: February 2007

Fragile X syndrome is a common heritable form of mental retardation in humans. Recent neuroanatomical studies indicate an apparent immature appearance of neurons in fragile X syndrome patients and fragile X mental retardation protein (FMRP)-knockout mice, an animal model of this condition. In this work, we investigated possible alterations in synaptic plasticity in the neocortex of FMRP-knockout mice. Extracellular field potentials were recorded from the deep-layer visual neocortex. Long-term potentiation (LTP) was severely attenuated in brain slices from knockout mice relative to that observed in slices from wild-type mice. Considering that neocortical LTP can involve both NMDA receptor-dependent and -independent mechanisms, we attempted to distinguish the nature of LTP attenuated in the knockout condition. In slices from wild-type mice, LTP was partially attenuated by the NMDA receptor antagonist 3-[(±)-2-carboxypiperazin-4-yl]-propyl-1-phosphate (CPP); however, the general metabotropic glutamate receptor (mGluR) antagonist α-methyl-4-carboxyphenylglycine (MCPG) strongly attenuated LTP, resulting in a response indistinguishable from that observed in slices from knockout mice. The selective mGluR
5
antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) attenuated LTP to a similar degree as did MCPG in wild-type slices, but MPEP did not alter the reduced potentiation in knockout slices. Our results suggest that LTP in layer V visual neocortex depends primarily on mGluR
5
activation. Our data also indicate that mGluR
5
-mediated synaptic plasticity is absent in the neocortex of FMRP-knockout mice. Such an alteration may contribute to the cognitive and learning deficits exhibited in these mice as well as in fragile X syndrome.
Disulfide formation as a probe of folding in GroEL–GroES reveals correct formation of long-range bonds and editing of incorrect short-range ones
Authors: Park Eun Sun , Fenton Wayne A. , Horwich Arthur L.
Published: February 2007

The chaperonin GroEL assists protein folding by binding nonnative forms through exposed hydrophobic surfaces in an open ring and mediating productive folding in an encapsulated hydrophilic chamber formed when it binds GroES. Little is known about the topology of nonnative proteins during folding inside the GroEL–GroES cis chamber. Here, we have monitored topology employing disulfide bond formation of a secretory protein, trypsinogen (TG), that behaves
in vitro
as a stringent, GroEL–GroES-requiring substrate. Inside the long-lived cis chamber formed by SR1, a single-ring version of GroEL, complexed with GroES, we observed an ordered formation of disulfide bonds. First, short-range disulfides relative to the primary structure formed, both native and nonnative. Next, the two long-range native disulfides that “pin” the two β-barrel domains together formed. Notably, no long-range nonnative bonds were ever observed, suggesting that a native-like long-range topology is favored. At both this time and later, however, the formation of several medium-range nonnative bonds mapping to one of the β-barrels was observed, reflecting that the population of local nonnative structure can occur even within the cis cavity. Yet both these and the short-range nonnative bonds were ultimately “edited” to native, as evidenced by the nearly complete recovery of native TG. We conclude that folding in the GroEL–GroES cavity can favor the formation of a native-like topology, here involving the proper apposition of the two domains of TG; but it also involves an ATP-independent conformational “editing” of locally incorrect structures produced during the dwell time in the cis cavity.
Deletion of CASK in mice is lethal and impairs synaptic function
Authors: Atasoy Deniz , Schoch Susanne , Ho Angela , Nadasy Krisztina A. , Liu Xinran , Zhang Weiqi , Mukherjee Konark , Nosyreva Elena D. , Fernandez-Chacon Rafael , Missler Markus , Kavalali Ege T. , Südhof Thomas C.
Published: February 2007

CASK is an evolutionarily conserved multidomain protein composed of an N-terminal Ca
2+
/calmodulin-kinase domain, central PDZ and SH3 domains, and a C-terminal guanylate kinase domain. Many potential activities for CASK have been suggested, including functions in scaffolding the synapse, in organizing ion channels, and in regulating neuronal gene transcription. To better define the physiological importance of CASK, we have now analyzed CASK “knockdown” mice in which CASK expression was suppressed by ≈70%, and CASK knockout (KO) mice, in which CASK expression was abolished. CASK knockdown mice are viable but smaller than WT mice, whereas CASK KO mice die at first day after birth. CASK KO mice exhibit no major developmental abnormalities apart from a partially penetrant cleft palate syndrome. In CASK-deficient neurons, the levels of the CASK-interacting proteins Mints, Veli/Mals, and neurexins are decreased, whereas the level of neuroligin 1 (which binds to neurexins that in turn bind to CASK) is increased. Neurons lacking CASK display overall normal electrical properties and form ultrastructurally normal synapses. However, glutamatergic spontaneous synaptic release events are increased, and GABAergic synaptic release events are decreased in CASK-deficient neurons. In contrast to spontaneous neurotransmitter release, evoked release exhibited no major changes. Our data suggest that CASK, the only member of the membrane-associated guanylate kinase protein family that contains a Ca
2+
/calmodulin-dependent kinase domain, is required for mouse survival and performs a selectively essential function without being in itself required for core activities of neurons, such as membrane excitability, Ca
2+
-triggered presynaptic release, or postsynaptic receptor functions.
Spinal cholinergic interneurons regulate the excitability of motoneurons during locomotion
Authors: Miles Gareth B. , Hartley Robert , Todd Andrew J. , Brownstone Robert M.
Published: February 2007

To effect movement, motoneurons must respond appropriately to motor commands. Their responsiveness to these inputs, or excitability, is regulated by neuromodulators. Possible sources of modulation include the abundant cholinergic “C boutons” that surround motoneuron somata. In the present study, recordings from motoneurons in spinal cord slices demonstrated that cholinergic activation of m
2
-type muscarinic receptors increases excitability by reducing the action potential afterhyperpolarization. Analyses of isolated spinal cord preparations in which fictive locomotion was elicited demonstrated that endogenous cholinergic inputs increase motoneuron excitability during locomotion. Anatomical data indicate that C boutons originate from a discrete group of interneurons lateral to the central canal, the medial partition neurons. These results highlight a unique component of spinal motor networks that is critical in ensuring that sufficient output is generated by motoneurons to drive motor behavior.
1-Methyl-4-phenylpyridinium induces synaptic dysfunction through a pathway involving caspase and PKCδ enzymatic activities
Authors: Serulle Yafell , Morfini Gerardo , Pigino Gustavo , Moreira Jorge E. , Sugimori Mutsuyuki , Brady Scott T. , Llinás Rodolfo R.
Published: February 2007

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine administration has been used, in various mammalian species, as an experimental model of Parkinson's disease. The pathogenesis for such pharmacologically induced Parkinson's disease involves 1-methyl-4-phenylpyridinium (MPP+), the active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. This metabolite produces rapid degeneration of nigrostriatal dopaminergic neurons, which causes the parkinsonian syndrome. In this work, we show that injection of MPP+ into the presynaptic terminal of the squid giant synapse blocks synaptic transmission without affecting the presynaptic action potential or the presynaptic calcium currents. These effects of MPP+ were mimicked by the injection of an active form of caspase-3 and prevented by inhibitors of caspase-3 and protein kinase C δ. Ultrastructurally, MPP+-injected synapses showed a dramatic reduction in the number of neurotransmitter vesicles at the presynaptic active zone, as compared with control synapses. Otherwise, normal docking and clathrin-coated vesicles were observed, albeit at much reduced numbers. These results indicate that MPP+ acutely reduces presynaptic vesicular availability, not release, and that MPP+-induced pathogenesis results from presynaptic dysfunction that leads, secondarily, to dying-back neuropathy in affected neurons.
1-Methyl-4-phenylpyridinium affects fast axonal transport by activation of caspase and protein kinase C
Authors: Morfini G. , Pigino G. , Opalach K. , Serulle Y. , Moreira J. E. , Sugimori M. , Llinás R. R. , Brady S. T.
Published: February 2007

Parkinson's disease (PD), a late-onset condition characterized by dysfunction and loss of dopaminergic neurons in the substantia nigra, has both sporadic and neurotoxic forms. Neurotoxins such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and its metabolite 1-methyl-4-phenylpyridinium (MPP+) induce PD symptoms and recapitulate major pathological hallmarks of PD in human and animal models. Both sporadic and MPP+-induced forms of PD proceed through a “dying-back” pattern of neuronal degeneration in affected neurons, characterized by early loss of synaptic terminals and axonopathy. However, axonal and synaptic-specific effects of MPP+ are poorly understood. Using isolated squid axoplasm, we show that MPP+ produces significant alterations in fast axonal transport (FAT) through activation of a caspase and a previously undescribed protein kinase C (PKCδ) isoform. Specifically, MPP+ increased cytoplasmic dynein-dependent retrograde FAT and reduced kinesin-1-mediated anterograde FAT. Significantly, MPP+ effects were independent of both nuclear activities and ATP production. Consistent with its effects on FAT, MPP+ injection in presynaptic domains led to a dramatic reduction in the number of membranous profiles. Changes in availability of synaptic and neurotrophin-signaling components represent axonal and synaptic-specific effects of MPP+ that would produce a dying-back pathology. Our results identify a critical neuronal process affected by MPP+ and suggest that alterations in vesicle trafficking represent a primary event in PD pathogenesis. We propose that PD and other neurodegenerative diseases exhibiting dying-back neuropathology represent a previously undescribed category of neurological diseases characterized by dysfunction of vesicle transport and associated with the loss of synaptic function.
Virstatin inhibits dimerization of the transcriptional activator ToxT
Authors: Shakhnovich Elizabeth A. , Hung Deborah T. , Pierson Emily , Lee Kyungae , Mekalanos John J.
Published: February 2007

The development of antimicrobials is critical in this time of increasing antibiotic resistance of most clinically relevant bacteria. To date, all current antibiotics focus on inhibiting crucial enzymatic activities of their protein targets (i.e., trimethoprim for dihydrofolate reductase), thus disrupting
in vitro
essential gene functions. In contrast, we have previously reported the identification of virstatin, a small molecule that inhibits virulence regulation in
Vibrio cholerae
, thereby preventing intestinal colonization in an infant mouse model for cholera. Virstatin prevents expression of the two major
V. cholerae
virulence factors, cholera toxin (CT) and the toxin coregulated pilus, by inhibiting the virulence transcriptional activator ToxT. It has previously been described that the N-terminal domain of ToxT has the ability to form homodimers. We now demonstrate that virstatin inhibits ToxT dimerization, thus demonstrating that it further falls into a unique class of inhibitors that works by disrupting protein-protein interactions, particularly homodimerization. Using virstatin, truncation mutants of ToxT, and a virstatin-resistant mutant, we show that dimerization is required for ToxT activation of the
ctx
promoter. In contrast, ToxT dimerization does not appear to be required at all of the other ToxT-regulated promoters, suggesting multiple mechanisms may exist for its transcriptional activity.
Midbody and primary cilium of neural progenitors release extracellular membrane particles enriched in the stem cell marker prominin-1
Authors: Dubreuil Véronique , Marzesco Anne-Marie , Corbeil Denis , Huttner Wieland B. , Wilsch-Bräuninger Michaela
Published: February 2007

Expansion of the neocortex requires symmetric divisions of neuroepithelial cells, the primary progenitor cells of the developing mammalian central nervous system. Symmetrically dividing neuroepithelial cells are known to form a midbody at their apical (rather than lateral) surface. We show that apical midbodies of neuroepithelial cells concentrate prominin-1 (CD133), a somatic stem cell marker and defining constituent of a specific plasma membrane microdomain. Moreover, these apical midbodies are released, as a whole or in part, into the extracellular space, yielding the prominin-1–enriched membrane particles found in the neural tube fluid. The primary cilium of neuroepithelial cells also concentrates prominin-1 and appears to be a second source of the prominin-1–bearing extracellular membrane particles. Our data reveal novel origins of extracellular membrane traffic that enable neural stem and progenitor cells to avoid the asymmetric inheritance of the midbody observed for other cells and, by releasing a stem cell membrane microdomain, to potentially influence the balance of their proliferation versus differentiation.
Assessment of the probabilities for evolutionary structural changes in protein folds
Authors: Vīksna Juris , Gilbert David
Published: February 2007

Motivation: The evolution of protein sequences can be described by a stepwise process, where each step involves changes of a few amino acids. In a similar manner, the evolution of protein folds can be at least partially described by an analogous process, where each step involves comparatively simple changes affecting few secondary structure elements. A number of such evolution steps, justified by biologically confirmed examples, have previously been proposed by other researchers. However, unlike the situation with sequences, as far as we know there have been no attempts to estimate the comparative probabilities for different kinds of such structural changes.

Results: We have tried to assess the comparative probabilities for a number of known structural changes, and to relate the probabilities of such changes with the distance between protein sequences. We have formalized these structural changes using a topological representation of structures (TOPS), and have developed an algorithm for measuring structural distances that involve few evolutionary steps. The probabilities of structural changes then were estimated on the basis of all-against-all comparisons of the sequence and structure of protein domains from the CATH-95 representative set.

The results obtained are reasonably consistent for a number of different data subsets and permit the identification of several ‘most popular’ types of evolutionary changes in protein structure. The results also suggest that alterations in protein structure are more likely to occur when the sequence similarity is >10% (the average similarity being ∼6% for the data sets employed in this study), and that the distribution of probabilities of structural changes is fairly uniform within the interval of 15–50% sequence similarity.

Availability: The algorithms have been implemented on the Windows operating system in C++ and using the Borland Visual Component Library. The source code is available on request from the first author. The data sets used for this study (representative sets of protein domains, matrices of sequence similarities and structural distances) are available on http://bioinf.mii.lu.lv/epsrc_project/struct_ev.html.

Contact:  juris.viksna@mii.lu.lv
The hepatocyte nuclear factor 6 (HNF6) and FOXA2 are key regulators in colorectal liver metastases
Authors: Lehner F. , Kulik U. , Klempnauer J. , Borlak J.
Published: February 2007

The molecular causes leading to secondary liver malignancies are unknown. Here we report regulation of major hepatic nuclear factors in human colorectal liver metastases and primary colonic cancer. Notably, the genes coding for HNF6, HNF1β, and C/EBPγ were selectively regulated in liver metastases. We therefore studied protein expression of regulated transcription factors and found unacetylated HNF6 to be a hallmark of colorectal liver metastases. For its known interaction with HNF6, we investigated expression of FOXA2, which we found to be specifically induced in colorectal liver metastases. By electromobility shift assay, we examined DNA binding of disease regulated transcription factors. Essentially, no HNF6 DNA binding was observed. We also searched for sequence variations in the DNA binding domains of HNF6, but did not identify any mutation. Furthermore, we probed for expression of 28 genes targeted by HNF6. Mostly transcript expression was repressed except for tumor growth. In conclusion, we show HNF6 protein expression to be driven by the hepatic environment. Its expression is not observed in healthy colon or primary colonic cancer. HNF6 DNA binding is selectively abrogated through lack of post‐translational modification and interaction with FOXA2. Targeting of FOXA2 and HNF6 may therefore enable mechanism‐based therapy for colorectal liver metastases.—Lehner, F., Kulik, U., Klempnauer, J., Borlak, J. The hepatocyte nuclear factor 6 (HNF6) and FOXA2 are key regulators in colorectal liver metastases. FASEB J. 21, 1445–1462 (2007)
DNA breaks are masked by multiple Rap1 binding in yeast: implications for telomere capping and telomerase regulation
Authors: Negrini Simona , Ribaud Virginie , Bianchi Alessandro , Shore David
Published: February 2007

Eukaryotic cells distinguish their chromosome ends from accidental DNA double-strand breaks by packaging them in a protective structure referred to as the telomere “cap.” Here we investigate the nature of the telomere cap by examining events at DNA breaks generated adjacent to either natural telomeric sequences (TG repeats) or arrays of Rap1-binding sites that vary in length. Although DNA breaks adjacent to either short or long telomeric sequences are efficiently converted into stable telomeres, they elicit very different initial responses. Short telomeric sequences (80 base pair [bp]) are avidly bound by Mre11, as well as the telomere capping protein Cdc13 and telomerase enzyme, consistent with their rapid telomerase-dependent elongation. Surprisingly, little or no Mre11 binding is detected at long telomere tracts (250 bp), and this is correlated with reduced Cdc13 and telomerase binding. Consistent with these observations, ends with long telomere tracts undergo strongly reduced exonucleolytic resection and display limited binding by both Rpa1 and Mec1, suggesting that they fail to elicit a checkpoint response. Rap1 binding is required for end concealment at long tracts, but Rif proteins, yKu, and Cdc13 are not. These results shed light on the nature of the telomere cap and mechanisms that regulate telomerase access at chromosome ends.
The small heterodimer partner is a gonadal gatekeeper of sexual maturation in male mice
Authors: Volle David H. , Duggavathi Rajesha , Magnier Benjamin C. , Houten Sander M. , Cummins Carolyn L. , Lobaccaro Jean-Marc A. , Verhoeven Guido , Schoonjans Kristina , Auwerx Johan
Published: February 2007

The small heterodimer partner (SHP) is an atypical nuclear receptor known mainly for its role in bile acid homeostasis in the enterohepatic tract. We explore here the role of SHP in the testis. SHP is expressed in the interstitial compartment of the adult testes, which contain the Leydig cells. SHP there inhibits the expression of steroidogenic genes, on the one hand by inhibiting the expression of the nuclear receptors steroidogenic factor-1 and liver receptor homolog-1 (lrh-1), and on the other hand by directly repressing the transcriptional activity of LRH-1. Consequently, in SHP knockout mice, testicular testosterone synthesis is increased independently of the hypothalamus–pituitary axis. Independent of its action on androgen synthesis, SHP also determines the timing of germ cell differentiation by controlling testicular retinoic acid metabolism. Through the inhibition of the transcriptional activity of retinoic acid receptors, SHP controls the expression of stimulated by retinoic acid gene 8 (stra8)—a gene that is indispensable for germ cell meiosis and differentiation. Together, our data demonstrate new roles for SHP in testicular androgen and retinoic acid metabolism, making SHP a testicular gatekeeper of the timing of male sexual maturation.
The effect of educational intervention on the adoption of nickel–titanium rotary instrumentation in a Public Dental Service
Authors: Reit C. , Bergenholtz G. , Caplan D. , Molander A.
Published: February 2007

Aim  To study the influence of two educational programmes on the adoption of nickel–titanium rotary instrumentation (NTRI) amongst general dental practitioners in a short‐term as well as a long‐term perspective.

Methodology  All dentists employed in the Gothenburg Dental service (n = 148) were enrolled in the study. The clinics in the organization were randomly assigned to one of two educational programmes. In the first programme a 4‐h lecture on root canal instrumentation was given. In the second programme the lecture course was supplemented by a 6‐h hands‐on training session. The short‐term effect was measured by a questionnaire distributed 6 months after completed education. The long‐term effect was evaluated 4 years later.

Results  The overall utilization rate of NTRI increased from 4% to 73%. However, lectures in combination with hands‐on training resulted in a better short‐term acceptance rate (94%) than if teaching was given only in lecture‐format (53%) (P = 0.000). As a consequence, all staff were offered hands‐on training. The long‐term adoption rate was 88%. Reasons for accepting the new technology usually were found within the ‘relative advantage’ category. Common reasons for dentists not to adopt NTRI were that they could not get started or that they found no advantage over the old technology.

Conclusions  The short‐term adoption of a new technology might be influenced by the design of an introductory educational programme. For clinical procedures, such as root canal instrumentation, the inclusion of hands‐on training sessions seems to be important to reach a high acceptance rate.
The effect of chemical inhibition of matrix metalloproteinases on the size of experimentally induced apical periodontitis
Authors: Tjäderhane L. , Hotakainen T. , Kinnunen S. , Ahonen M. , Salo T.
Published: February 2007

Aim To determine the effect of matrix metalloproteinase (MMP) inhibition on periapical lesion formation in a rat model.

Methodology The pulp chambers of mandibular fist molars of adult SD rats were exposed to be infected by oral microbes. The experimental group was fed 20 mg kg−1MMP‐inhibitor chemically modified tetracycline‐3 (CMT‐3) daily in an oral gavage and the controls were fed the vehicle. After 2 and 4 weeks, the mandibles (n = 10 in both groups at both times) were radiographed, decalcified and subjected to histological analysis. Extension of necrosis in first molar distal root canals was measured from the histological sections, and periapical lesion sizes in the same roots were determined from radiographs and histological sections. Mann–WhitneyU‐test was used for the statistical analysis.

Results There was a statistically significant difference in the extension of necrosis in root canals between 2 and 4 weeks in the control group (P < 0.05), but not with MMP inhibition. Radiographically, MMP inhibition increased the periapical lesion size by 70% and 34% after 2 and 4 weeks respectively (P < 0.05 in after 2 weeks). In histological measurements, lesion size increased with MMP inhibition by 26% and 8% after 2 and 4 weeks respectively.

Conclusions MMP inhibition affects pulpal and periapical inflammation, increasing the rate of spreading of necrosis in root canals and the rate of periapical lesion formation.
Safety of selective cyclooxygenase‐2 inhibitors and a basic non‐steroidal anti‐inflammatory drug (NSAID) in Japanese patients with NSAID‐induced urticaria and/or angioedema: Comparison of meloxicam, etodolac and tiaramide
Authors: INOMATA Naoko , OSUNA Hiroyuki , YAMAGUCHI Junko , ONODA Masahito , TAKESHITA Yoshihiro , CHIBA Yoshiyuki , KAMBARA Takeshi , IKEZAWA Zenro
Published: February 2007

The identification of a safe and reliable alternative for patients with non‐steroidal anti‐inflammatory drug (NSAID)‐induced urticaria/angioedema is a frequent problem for dermatologists and other practitioners. Cyclooxygenase‐2 (COX‐2) inhibitors have been reported to be safe for NSAID‐intolerant patients from the US and Europe but not all of them have yet been approved for use in Japan. It was our objective to investigate the clinical manifestations of oral NSAID challenges in Japanese patients with histories of urticaria and/or angioedema after the intake of NSAIDs and to find safe alternative drugs, including COX‐2 inhibitors and a basic anti‐inflammatory drug. Twenty subjects suspected NSAID‐induced urticaria/angioedema from histories were included in a double‐blind or single‐blind, placebo‐controlled oral challenge protocol using NSAIDs. Skin prick tests using NSAIDs, which were dissolved in saline, were conducted. The mean age of the patients was 37.3 years; 14 patients were female. The results of other challenge tests showed that the most frequently intolerated drugs was loxoprofen (100%), followed by acetyl salicylic (94.4%), etodolac (53.3%), dicrofenac (50%), acetaminophen (38.5%), meloxicam (33%), and tiaramide (21.4%). Urticaria and angioedema were induced after aspirin intake in 83.3% and 22.2% of patients, respectively, whereas an asthmatic response was seen in 5.6%. Skin prick tests with NSAIDs were 100% negative. This study showed that among the NSAIDs that are available in Japan and that were investigated in this study, tiaramide, which does not inhibit COX, is the relatively safe alternative drug for Japanese patients with NSAID‐induced urtiacaria and/or angioedema. Furthermore, meloxicam seems to be better tolerated than etodolac between two selective COX‐2 inhibitors.
Case of skin necrosis due to arginine monohydrochloride extravasation
Authors: BASSI Elisa , LONATI Davide , PANDOLFI Roberta , GATTI Marco , JOLLIFFE Victoria M.L. , FORNO Corrado Del
Published: February 2007

A 10‐month‐old child presented with an ulcerated lesion on his right arm. The lesion was caused by arginine monohydrochloride extravasation during growth hormone testing, performed 2 months before. On physical examination, there was a 3 cm × 4 cm oval sore, with a thick fibrous base and turgid, violaceous, raised edges on the dorsal aspect of the child's right hand and wrist. Conservative management with local medications led to complete resolution within 2 months.
Effectiveness of a multi‐disciplinary standardized management model in the treatment of chronic hepatitis C in drug addicts engaged in detoxification programmes
Authors: Guadagnino Vincenzo , Trotta Maria Paola , Montesano Franco , Babudieri Sergio , Caroleo Benedetto , Armignacco Orlando , Carioti Jessica , Maio Giuseppe , Monarca Roberto , Antinori Andrea ,   Nocchiero Study Group
Published: February 2007

Aim To evaluate the effect of a multi‐disciplinary standardized management model on the efficacy of pegylated (Peg)‐interferon α‐2b plus ribavirin treatment of chronic hepatitis C in drug addicts undergoing substitutive or antagonist therapy.

Design Observational prospective multi‐centre study.

Setting Six clinical infectious disease centres in collaboration with 11 drug dependency units (DDU) in five Italian regions.

Participants Intravenous drug users affected by chronic hepatitis C engaged in detoxification programmes.

Methods Application of a multi‐disciplinary standardized management model for HCV treatment involving DDU operators, psychologists or psychiatrists and infectious disease specialists.

Measurements Very early, early, end‐of‐treatment and sustained virological response to Peg‐interferon α‐2b plus ribavirin.

Findings Fifty‐three subjects were studied [43.4% with hepatitis C virus (HCV) genotypes 1 or 4]. Intent‐to‐treat analysis showed an end‐of‐treatment virological response in 58.5% of patients (39.1% genotypes 1 or 4; 73.4% genotype 3) and a sustained virological response in 54.7% (34.8% genotypes 1 or 4; 70.0% genotype 3). There were 19 (35.8%) dropouts and three (5.7%) non‐responders: one genotype 1 and two genotype 4. Two (3.8%) patients relapsed: genotypes 1 and 3. On‐treatment analysis showed negative HCV‐RNA in 40 (93.1%) of 43 subjects who completed the first 12 treatment weeks and in 35 who completed the first 24 treatment weeks. All subjects with an end‐of‐treatment response, except one with genotype 3 infection, had a sustained response.

Conclusions Our data show that antiviral treatment in the context of a multi‐disciplinary standardized management model helps many HCV‐positive drug addicts achieve a good virological response.
Spatial and non‐spatial risk factors associated with cage‐level distribution of infectious salmon anaemia at three Atlantic salmon, Salmo salar L., farms in Maine, USA
Authors: Gustafson L , Ellis S , Robinson T , Marenghi F , Merrill P , Hawkins L , Giray C , Wagner B
Published: February 2007

The distribution of infectious salmon anaemia (ISA) was examined among 80 cages from three Atlantic salmon grow‐out farms in Maine, USA that were stocked with smolts from a single hatchery. Cage‐level disease was broadly defined as one or more moribund fish testing positive for infectious salmon anaemia virus (ISAV) by RT‐PCR and a second confirmatory test (IFAT, culture or genotype sequence). Spatio‐temporal and cage‐level risks were explored using logistic regression and survival analysis. Non‐spatial risk factors associated with ISA, or shortened survival time to disease, included increased predation, trucking company choice for smolt transfers, a finely‐sedimented benthic substrate, and smaller average size of smolts at stocking. Univariable analysis identified the time‐dependent spatial factor ‘adjacency to newly infected cages’ to be predictive of new infection in neighbouring cages 11–12 weeks later. However, none of the spatial factors, or their lags retained relevance in multiple‐variable models. The results suggest a diffuse distribution of virus exposure throughout infected sites, with host‐susceptibility factors probably influencing disease manifestation in individual cages. The narrow focus of the current study may limit application of the findings to other sites and year‐classes. However, these data support the relevance of husbandry efforts to optimize fish health in regions affected by ISAV.
Geographical variation in the prevalence of positive skin tests to environmental aeroallergens in the European Community Respiratory Health Survey I
Authors: Bousquet P.‐J. , Chinn S. , Janson C. , Kogevinas M. , Burney P. , Jarvis D.
Published: February 2007

Background:  Many studies have reported the prevalence of sensitization using skin prick tests. However, comparisons between studies and between regions are difficult because the number and the type of allergens tested vary widely. Using the European Community Health Respiratory Survey I data, the geographical variation of sensitization to environmental allergen as measured by skin tests was established.

Methods:  Adults aged 20–44 years, living in 35 centres in 15 developed countries, underwent skin tests for allergy to nine common aeroallergens: Dermatophagoides pteronyssinus, timothy grass, cat, Cladosporium herbarium, Alternaria alternata, birch, Olea europea, common ragweed and Parietaria judaica. The age–sex standardized prevalence of sensitization was determined and centres with high (95% confidence interval above and excluding study median) and low prevalence (95% confidence interval below and excluding study median) of sensitization to each allergen and to any of the nine allergens were identified.

Results:  There was substantial geographical variation in the prevalence of sensitization to each of the nine allergens tested and in the prevalence of sensitization to any allergen (lowest 17.1%, median 36.8% and highest 54.8%). Sensitization to D. pteronyssinus, grass pollen and cat were usually the most prevalent (median between centre 21.7%, 16.9% and 8.8%, respectively). Timothy grass sensitization was higher than that for any other pollen species.

Conclusions:  As expected, geographical variations of sensitization to environmental allergen were observed across centres. These findings were compatible for those observed with serum‐specific IgE. Skin tests can be used to assess the geographical distribution of allergens in a multicentric epidemiological survey.
Air Contact Influences the pH of Extended Porcine Semen
Authors: Vyt P , Maes D , Sys SU , Rijsselaere T , Van Soom A
Published: February 2007

Contents

In this study, the pH‐rise during storage of extended porcine semen was examined. This pH‐rise was found to be caused by CO2‐loss from the buffering system in the extender and was more pronounced with increasing air volume in the recipient. An influence on sperm motility parameters was observed between semen samples stored in the presence of different amounts of ambient air in the recipient. Velocity parameters and percentage motile spermatozoa were significantly lower for semen stored in recipients with higher air volume and elevated pH. Adjusting extender preparation by avoiding air contact in commercial AI‐centres may minimize the pH‐rise and its influence on sperm motility.
Clinical and pathological characteristics and outcomes of Chinese patients with primary anti‐neutrophil cytoplasmic antibodies‐associated systemic vasculitis with immune complex deposition in kidney
Authors: YU FENG , CHEN MIN , WANG SU‐XIA , ZOU WAN‐ZHONG , ZHAO MING‐HUI , WANG HAI‐YAN
Published: February 2007

Aim: To analyse the clinical and pathological characteristics of Chinese patients with immune complex deposition in kidney in anti‐neutrophil cytoplasmic antibodies (ANCA)‐positive vasculitis.

Methods: Enrolled in this study are patients with immune complex deposition in kidney in ANCA‐positive vasculitis diagnosed in Peking University First Hospital. Their clinical and pathological data were collected and analysed.

Results: Twenty‐three patients were eligible. Fifteen patients were with microscopic polyangiitis and eight patients were with Wegener's granulomatosis. The mean age was 48.8 years and with a male/female ratio of 10/13. The interval, between onset of disease and the diagnosis of disease, was 429.6 ± 693.3 days. All patients had clinical evidence of renal involvement. The major immunoglobulin deposited was IgM and the main locations were mesangial and sub‐epithelial area. Four patients also presented features of membranous nephropathy and six patients presented features of IgA nephropathy. About 52.2% of patients had hypocomplementaemia. All patients received immunosuppressive therapy and all of them achieved clinical remission. Patients were followed for about 28.8 ± 25.3 months. Nine patients kept clinical remission, nine patients progressed to end‐stage renal disease and five patients died. When these patients are compared with patients who had classical pauci‐immune vasculitis, they had greater proteinuria (P < 0.05), higher prevalence of hypocomplementaemia (P < 0.05) and greater glomerular cellularity (P < 0.05).

Conclusion: The present study showed that the features of patients with ANCA‐associated vasculitis with immune complex deposition in kidney were similar with classical ‘pauci‐immune’ vasculitis except for more proteinuria, more hypocomplementaemia and greater glomerular hypercellularity.
Effects of interleukin 18 on injury and activation of human proximal tubular epithelial cells
Authors: LIANG DONG , LIU HUA‐FENG , YAO CUI‐WEI , LIU HAI‐YAN , HUANG‐FU CHANG‐MEI , CHEN XIANG‐WEN , DU SHEN‐HUA , CHEN XIAO‐WEN
Published: February 2007

Background/Aims:  Injury and activation of tubular proximal epithelial cells (TEC) play central roles in renal tubulointerstitial fibrosis (TIF), but its mechanisms remain obscure. Interleukin 18 (IL‐18) is overproduced during chronic kidney diseases (CKD), but how IL‐18 affects the biological behaviour of TEC is not clear. The aim of the present study is to reveal the role of IL‐18 in renal TIF.

Methods:  The expressions of IL‐18 and IL‐18 receptor in TEC were detected by immunohistochemical staining in vivo and by reverse transcriptase polymerase chain reaction (RT‐PCR) in vitro. TEC line (HK‐2 cells) were incubated without or with IL‐18. Cell proliferation and cell cycle were evaluated by methyl thiazolyl tetrazolium assay and flow cytometric analysis, respectively. Cell apoptosis was assessed by Hoechst 33258 staining. Expression of α‐smooth muscle actin was evaluated by RT‐PCR, immunocytochemical staining and flow cytometric analysis, respectively. Type I collagen, fibronectin, MCP‐1 and RANTES in cultured supernatants were measured by enzyme‐linked immunosorbent assay.

Results:  IL‐18 expression in TEC increased significantly in CKD state. IL‐18 receptor was constitutively expressed in normal proximal TEC, and its expression increased strongly in CKD state. Proliferation and cell cycle of HK‐2 cells were not affected by IL‐18. Cell apoptosis, α‐smooth muscle actin expression, type I collagen and fibronectin production as well as MCP‐1 secretion were promoted by IL‐18 in dosage‐ and/or time‐dependent manners, but RANTES secretion was not affected.

Conclusion:  IL‐18 may play a crucial role in the process of TIF by promoting TEC injury and activation, and could be a target of the therapeutic approaches against TIF.
Darbepoetin alfa administered monthly maintains haemoglobin concentrations in patients with chronic kidney disease not receiving dialysis: A multicentre, open‐label, Australian study
Authors: DISNEY ALEX , JERSEY PETER DE , KIRKLAND GEOFF , MANTHA MURTY , CHARLESWORTH JOHN A , GALLAGHER MARTIN , HARRIS DAVID , GOCK HILTON , MANGOS GEORGE J , MACMILLAN JAMIE , LIU WEI , VISWALINGAM AJIT
Published: February 2007

Aim:  Darbepoetin alfa, an erythropoiesis‐stimulating protein, has a longer serum half‐life than recombinant human erythropoietin, allowing less‐frequent administration. This study aimed to demonstrate that once‐monthly (QM) darbepoetin alfa administration would maintain haemoglobin (Hb) concentrations in subjects with chronic kidney disease (CKD) not receiving dialysis who had previously been administered darbepoetin alfa every 2 weeks (Q2W).

Methods:  This was a multicentre study in which subjects with CKD receiving stable Q2W darbepoetin alfa doses and with stable Hb (100–130 g/L) were started on QM darbepoetin alfa dosing. The initial QM darbepoetin alfa dose was equivalent to the cumulative darbepoetin alfa dose administered during the month preceding enrolment. Darbepoetin alfa doses were titrated to maintain Hb concentrations between 100 and 130 g/L. The primary endpoint was the proportion of subjects maintaining mean Hb 0e; 100 g/L during the evaluation period (weeks 21–33).

Results:  Sixty‐six subjects were enrolled in the study and all received at least one dose of darbepoetin alfa; 55 (83%) had mean Hb 0e; 100 g/L during evaluation. Mean (SD) Hb concentrations at baseline and during the evaluation period were 119 (8.7) g/L and 114 (9.8) g/L, respectively. The median QM darbepoetin alfa dose at baseline and during the evaluation period was 80 μg. Darbepoetin alfa was considered to be well‐tolerated.

Conclusion:  Patients with CKD not receiving dialysis who are receiving darbepoetin alfa Q2W can be safely and effectively extended to darbepoetin alfa QM. Dosing QM may simplify anaemia management for patients and health‐care providers.
Nursing care and understanding the experiences of others: a Gadamerian perspective
Authors: Phillips Brian
Published: February 2007

A personal and professional issue that confronts all nurses is that of attempting to understand the experiences of our patients or clients. The position taken here is that understanding another person as a human being is much more than being able to explain their experience according to a particular model of ill‐health. Rather, it is an issue of human dignity and respectfulness. Gadamerian hermeneutics has been used in nursing research to articulate the process of understanding and to develop interpretations of particular experiences. Gadamer's exposition of understanding shows that we need to be aware that our understanding of other people is developed through a fusion of our own history, language and culture with that of the other person. This occurs through a hermeneutic question–answer dialogue in which we put our ideas at risk of being modified or rejected in the process. Understanding then, is a perceptual and conceptual process in which we fully participate. In this way, the experience of understanding those we nurse increases our understanding of ourselves as well as enhancing our ability to further understand others.
Ultrastructure and large subunit rDNA sequences ofLepidodinium viridereveal a close relationship toLepidodinium chlorophorumcomb. nov. (=Gymnodinium chlorophorum)
Authors: Hansen Gert , Botes Lizeth , De Salas Miguel
Published: February 2007

The ultrastructure of the green dinoflagellateLepididodinium virideM. M. Watanabe, S. Suda, I. Inouye Sawaguchi et Chihara was studied in detail. The nuclear envelope possessed numerous chambers each furnished with a nuclear pore, a similar arrangement to that found in other gymnodinioids. The flagellar apparatus was essentially identical toGymnodinium chlorophorumElbrächter et Schnepf, a species also containing chloroplasts of chlorophyte origin. Of particular interest was the connection of the flagellar apparatus to the nuclear envelope by means of both a fiber and a microtubular extension of the R3 flagellar root. This feature has not been found in other dinoflagellates and suggests a close relationship between these two species. This was confirmed by phylogenetic analysis based on partial sequences of the large subunit (LSU) rDNA gene ofL. viride, G. chlorophorumand 16 other unarmoured dinoflagellates, including both the ‘type’ culture and a new Tasmanian isolate ofG. chlorophorum. These two isolates had identical sequences and differed fromL. virideby only 3.75% of their partial LSU sequences, considerably less than the difference between otherGymnodiniumspecies. Therefore, based on ultrastructure, pigments and partial LSU rDNA sequences, the genusLepidodiniumwas emended to encompassL. chlorophorumcomb. nov.
A fatigue model with local sensitivity analysis
Authors: CASTILLO E. , FERNÁNDEZ‐CANTELI A. , HADI A. S. , LÓPEZ‐AENLLE M.
Published: February 2007

The goal of this paper is two fold. First, it introduces a general parametric lifetime model for high‐cycle fatigue regime derived from physical, statistical, engineering and dimensional analysis considerations. The proposed model has two threshold parameters and three Weibull distribution parameters. A two‐step procedure is presented to estimate the parameters. In the first step, the two threshold parameters are estimated by minimizing a least squares regression function. In the second step, the parameters are estimated by the maximum likelihood method after pooling together the data from different stress levels. Since parameter estimation should always be accompanied by a sensitivity analysis of the fitted model, the second goal of this paper is to propose a method for sensitivity analysis for fatigue models. We show that the proposed sensitivity analysis methods are general and can be applied to any fatigue or lifetime model, not just to the one proposed here. Although several fatigue models have been proposed in the literature, to our knowledge this is the first attempt to produce methods for sensitivity analysis for fatigue models. The proposed method makes use of the well‐known duality property of mathematical programming, which states that the partial derivatives of the primal objective function with respect to the constraints right hand side parameters are the optimal values of the negative of the dual problem variables. For the parameters or data, for which sensitivities are sought, to appear on the right hand side, they are converted into artificial variables and set to their actual values, thus obtaining the desired constraints. Both the estimation and sensitivity analysis methods are illustrated by two examples, one application using real fatigue data and the other using simulated data. In addition, the sensitivity proposed method is also applied to an alternative fatigue model. Finally, some specific conclusions and recommendations are also given.
Carbohydrates and dietary fibre
Authors: Lunn J. , Buttriss J. L.
Published: February 2007

Summary  The health benefits of including sufficient dietary fibre in the diet have been well described and have formed the basis of dietary recommendations around the world. However, dietary fibre is a complex dietary entity, consisting of many non‐digestible components of food. Debate surrounding the definition and measurement of dietary fibre has resulted in inconsistencies in labelling, description and recommendations set across the world. In the UK, dietary recommendations are made using the fraction of non‐digestible material described as non‐starch polysaccharide that is measured by the Englyst method. However, the Association of Official Analytical Chemists (AOAC) methods, used widely by the food industry, capture a much greater range of non‐digestible material, that some suggest should be included in any definition of dietary fibre. An attempt to resolve such discrepancies, possibly by taking an approach that considers the health effects of fractions not captured in the Englyst method, is probably overdue.

Additionally, it is clear that the effects of these various non‐digestible components of dietary fibre are not interchangeable, and it is important that fibre comes from a range of sources to ensure maximum health benefits from the fibre in the diet. Traditional ‘insoluble’ fibres are required to add bulk as well as rapidly fermentable, viscous fibres to bring about cholesterol lowering. There is also a convincing argument for including slowly fermented components, such as resistant starches, that are well tolerated in the digestive system and can bring about improvements in gut function. Currently there is insufficient data from well designed human intervention trials to make specific recommendations on the amounts of these fibre components in the diet, but it may be useful for health professionals to talk in terms of the different food sources of these types of fibre, as well as total fibre amounts.