bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of various light curing methods on the leachability of uncured substances and hardness of a composite resin
Authors: Moon H.‐J. , Lee Y.‐K. , Lim B.‐S. , Kim C.‐W.
Published: March 2007

summary  The purpose of this study was to evaluate the effect of the various light curing units (plasma arc, halogen and light‐emitting diodes) and irradiation methods (one‐step, two‐step and pulse) using different light energy densities on the leachability of unreacted monomers (Bis‐GMA and UDMA) and the surface hardness of a composite resin (Z250, 3M). Leachability of the specimens immersed for 7 days in ethanol was analysed by HPLC. Vicker's hardness number (VHN) was measured immediately after curing (IC) and after immersion in ethanol for 7 days. Various irradiation methods with three curing units resulted in differences in the amount of leached monomers and VHN of IC when light energy density was lower than 17·0 J cm−2 (P = 0·05). However, regardless of curing units and irradiation methods, these results were not different when the time or light energy density increased. When similar light energy density was irradiated (15·6–17·7 J cm−2), the efficiency of irradiation methods was different by the following order: one‐step ≥ two‐step > pulse. These results suggest that the amount of leached monomers and VHN were influenced by forming polymer structure in activation and initiation stages of polymerization process with different light source energies and curing times.
Genetic differentiation between Príncipe Island and mainland populations of the grey parrot (Psittacus erithacus), and implications for conservation
Authors: MELO MARTIM , O’RYAN COLLEEN
Published: March 2007

The range of the grey parrot (Psittacus erithacus), one of the most heavily harvested bird species for the international pet trade, spans the forest belt of Central and West Africa and includes the oceanic island of Príncipe (Gulf of Guinea). Morphological variation led to the recognition of two mainland subspecies (P. e. erithacusandP. e. timneh). The population from Príncipe was originally described as a separate species (P. princeps) but is currently included in the nominate race. We used 1932 bp of the mitochondrial genome to clarify the genealogical affinities between the two currently‐recognized mainland subspecies and the Príncipe population. Sampling included 20 individuals from Príncipe, 17 fromP. e. erithacus, and 13 fromP. e. timneh. We found that the two mainland subspecies form two independent lineages, having diverged up to 2.4 million years ago (Ma), and that the Príncipe population is composed of two lineages that diverged in allopatry. The most common lineage is descended from the first colonizers and evolved in isolation for up to 1.4 Ma. Contrary to current understanding, this ‘Príncipe lineage’ is more closely related to thetimnehthan to theerithacussubspecies. The second lineage consists ofP. e. erithacusbirds from the nearby mainland that colonized the island in recent times. The evolutionary dynamics of the grey parrot population of Príncipe are primarily characterized by isolation, with new genetic variation being added through rare immigration events. The heavily harvested Príncipe grey parrot population should therefore be treated as an independent conservation unit.
The influence of altitude and topography on genetic structure in the long‐toed salamander (Ambystoma macrodactulym)
Authors: GIORDANO ANDREW R. , RIDENHOUR BENJAMIN J. , STORFER ANDREW
Published: March 2007

A primary goal of molecular ecology is to understand the influence of abiotic factors on the spatial distribution of genetic variation. Features including altitudinal clines, topography and landscape characteristics affect the proportion of suitable habitat, influence dispersal patterns, and ultimately structure genetic differentiation among populations. We studied the effects of altitude and topography on genetic variation of long‐toed salamanders (Ambystoma macrodactylum), a geographically widespread amphibian species throughout northwestern North America. We focused on 10 low altitude sites (< 1200 m) and 11 high‐altitude sites in northwestern Montana and determined multilocus genotypes for 549 individuals using seven microsatellite loci. We tested four hypotheses: (1) gene flow is limited between high‐ and low‐altitude sites; and, (2) gene flow is limited among high‐altitude sites due to harsh habitat and extreme topographical relief between sites; (3) low‐altitude sites exhibit higher among‐site gene flow due to frequent flooding events and low altitudinal relief; and (4) there is a negative correlation between altitude and genetic variation. Overall FST values were moderate (0.08611; P < 0.001). Pairwise FST estimates between high and low populations and a population graphing method supported the hypothesis that low‐altitude and high‐altitude sites, taken together, are genetically differentiated from each other. Also as predicted, gene flow is more prominent among low‐altitude sites than high‐altitude sites; low‐altitude sites had a significantly lower FST (0.03995; P < 0.001) than high altitude sites (FST = 0.10271; P < 0.001). Use of Bayesian analysis of population structure (BAPS) resulted in delineation of 10 genetic groups, two among low‐altitude populations and eight among high‐altitude populations. In addition, within high altitude populations, basin‐level genetic structuring was apparent. A nonequilibrium algorithm for detecting current migration rates supported these population distinctions. Finally, we also found a significant negative correlation between genetic diversity and altitude. These results are consistent with the hypothesis that topography and altitudinal gradients shape the spatial distribution of genetic variation in a species with a broad geographical range and diverse life history. Our study sheds light on which key factors limit dispersal and ultimately species’ distributions.
Phylogenetic evidence for an animal pathogen origin of ergot and the grass endophytes
Authors: SPATAFORA J. W. , SUNG G.‐H. , SUNG J.‐M. , HYWEL‐JONES N. L. , WHITE J. F.
Published: March 2007

Grass‐associated fungi (grass symbionts) in the family Clavicipitaceae (Ascomycota, Hypocreales) are species whose host range is restricted to the plant family Poaceae and rarely Cyperaceae. The best‐characterized species include Claviceps purpurea (ergot of rye) and Neotyphodium coenophialum (endophyte of tall fescue). They have been the focus of considerable research due to their importance in agricultural and grassland ecosystems and the diversity of their bioactive secondary metabolites. Here we show through multigene phylogenetic analyses and ancestral character state reconstruction that the grass symbionts in Clavicipitaceae are a derived group that originated from an animal pathogen through a dynamic process of interkingdom host jumping. The closest relatives of the grass symbionts include the genera Hypocrella, a pathogen of scale insects and white flies, and Metarhizium, a generalist arthropod pathogen. These data do not support the monophyly of Clavicipitaceae, but place it as part of a larger clade that includes Hypocreaceae, a family that contains mainly parasites of other fungi. A minimum of 5–8 independent and unidirectional interkingdom host jumps has occurred among clavicipitaceous fungi, including 3–5 to fungi, 1–2 to animals, and 1 to plants. These findings provide a new evolutionary context for studying the biology of the grass symbionts, their role in plant ecology, and the evolution of host affiliation in fungal symbioses.
Panmictic population structure in the hooded seal (Cystophora cristata)
Authors: COLTMAN D. W. , STENSON G. , HAMMILL M. O. , HAUG T. , DAVIS C. S. , FULTON T. L.
Published: March 2007

Two putative populations of hooded seals (Cystophora cristata) occur in the North Atlantic. The Greenland Sea population pup and breed on the pack ice near Jan Mayen (‘West Ice’) while the Northwest Atlantic population is thought to pup in the Davis Strait, in the Gulf of St. Lawrence (the ‘Gulf’), and off southern Labrador or northeast Newfoundland (the ‘Front’). We used microsatellite profiling of 300 individuals at 13 loci and mitochondrial DNA sequencing of the control region of 123 individuals to test for genetic differentiation between these four breeding herds. We found no significant genetic differences between breeding areas, nor evidence for cryptic nor higher level genetic structure in this species. The Greenland Sea breeding herd was genetically most distant from the Northwest Atlantic breeding areas; however, the differences were statistically nonsignificant. Our data therefore suggest that the world's hooded seals comprise a single panmictic genetic population.
Detecting genetic structure in migrating bowhead whales off the coast of Barrow, Alaska
Authors: JORDE P. E. , SCHWEDER T. , BICKHAM J. W. , GIVENS G. H. , SUYDAM R. , HUNTER D. , STENSETH N. C.
Published: March 2007

We develop a general framework for analysing and testing genetic structure within a migratory assemblage that is based on measures of genetic differences between individuals. We demonstrate this method using microsatellite DNA data from the Bering‐Chukchi‐Beaufort stock of bowhead whales (Balaena mysticetus), sampled via Inuit hunting during the spring and autumn migration off Barrow, Alaska. This study includes a number of covariates such as whale ages and the time separation between captures. Applying the method to a sample of 117 bowhead whales, we use permutation methods to test for temporal trends in genetic differences that can be ascribed to age‐related effects or to timing of catches during the seasons. The results reveal a pattern with elevated genetic differences among whales caught about a week apart, and are statistically significant for the autumn migration. In contrast, we find no effects of time of birth or age‐difference on genetic differences. We discuss possible explanations for the results, including population substructuring, demographic consequences of historical overexploitation, and social structuring during migration.
Water balance in the Argentine ant (Linepithema humile) compared with five common native ant species from southern California
Authors: SCHILMAN PABLO E. , LIGHTON JOHN R. B. , HOLWAY DAVID A.
Published: March 2007

Abstract Little attention has been given to the effect of physiological limitations on the ability of introduced species to invade ecological communities. In the present study, the water balance of the invasive Argentine ant (Linepithema humile) is compared with five common ant species native to southern California. Total and critical water contents are measured, as well as rates of water loss and survival times. The results show that the body size of ant species has a strong effect on water balance, explaining between 99% of total and 90% of critical water content (i.e. the amount of water remaining when the ant becomes moribund). The measured survival times at 40 °C and approximately 0% relative humidity are shorter for L. humile than for the other five native ant species. The area‐independent water‐loss rate is higher for L. humile than for the other native ant species studied. This finding is corroborated by independent data using two different methods (i.e. gravimetric measurement and open‐flow respirometry). Somewhat surprisingly, significant differences in the water‐loss rates of different sizes of Solenopsis xyloni workers are found, even after adjusting for surface area. The area‐independent water‐loss rate is significantly lower for larger than for smaller workers. Consistent with circumstantial evidence from the field, the results suggest that the physiological constraints of invasive species, such as water‐loss rates and critical water content, can limit their distribution and abundance not only at regional scales, but also at fine scales.
Circadian rhythm of locomotor activity in the Japanese honeybee, Apis cerana japonica
Authors: FUCHIKAWA TARO , SHIMIZU ISAMU
Published: March 2007

Abstract To reveal circadian characteristics and entrainment mechanisms in the Japanese honeybee Apis cerana japonica, the locomotor‐activity rhythm of foragers is investigated under programmed light and temperature conditions. After entrainment to an LD 12 : 12 h photoperiodic regime, free‐running rhythms are released in constant dark (DD) or light (LL) conditions with different free‐running periods. Under the LD 12 : 12 h regime, activity offset occurs approximately 0.4 h after lights‐off transition, assigned to circadian time (Ct) 12.4 h. The phase of activity onset, peak and offset, and activity duration depends on the photoperiodic regimes. The circadian rhythm can be entrained to a 24‐h period by exposure to submultiple cycles of LD 6 : 6 h, as if the locomotive rhythm is entrained to LD 18 : 6 h. Phase shifts of delay and advance are observed when perturbing single light pulses are presented during free‐running under DD conditions. Temperature compensation of the free‐running period is demonstrated under DD and LL conditions. Steady‐state entrainment of the locomotor rhythm is achieved with square‐wave temperature cycles of 10 °C amplitude, but a 5 °C amplitude fails to entrain.
The auxin‐binding protein 1 is essential for the control of cell cycle
Authors: David Karine M. , Couch Daniel , Braun Nils , Brown Spencer , Grosclaude Jeanne , Perrot‐Rechenmann Catherine
Published: March 2007

The phytohormone auxin has been known for >50 years to be required for entry into the cell cycle. Despite the critical effects exerted by auxin on the control of cell division, the molecular mechanism by which auxin controls this pathway is poorly understood, and how auxin is perceived upstream of any change in the cell cycle is unknown. Auxin Binding Protein 1 (ABP1) is considered to be a candidate auxin receptor, triggering early modification of ion fluxes across the plasma membrane in response to auxin. ABP1 has also been proposed to mediate auxin‐dependent cell expansion, and is essential for early embryonic development. We investigated whether ABP1 has a role in the cell cycle. Functional inactivation of ABP1 in the model plant cell system BY2 was achieved through cellular immunization via the conditional expression of a single‐chain fragment variable (scFv). This scFv was derived from a well characterized anti‐ABP1 monoclonal antibody previously shown to block the activity of the protein. We demonstrate that functional inactivation of ABP1 results in cell‐cycle arrest, and provide evidence that ABP1 plays a critical role in regulation of the cell cycle by acting at both the G1/S and G2/M checkpoints. We conclude that ABP1 is essential for the auxin control of cell division and is likely to constitute the first step of the auxin‐signalling pathway mediating auxin effects on the cell cycle.
Composition of alkyl esters in the cuticular wax on inflorescence stems of Arabidopsis thaliana cer mutants
Authors: Lai Christine , Kunst Ljerka , Jetter Reinhard
Published: March 2007

Wax biosynthetic pathways proceed via the elongation of 16:0 acyl‐CoA to very long‐chain fatty acids (VLCFA), and by further modifications that include reduction to primary alcohols and formation of alkyl esters. We have analyzed the alkyl esters in the stem wax of ten cer mutants of Arabidopsis thaliana together with the corresponding wild types. Alkyl esters with chain lengths between C38 and C52 were identified, and the levels of esters ranged from 0.15 µg cm−2 in Wassilewskija (WS) to 1.20 µg cm−2 in cer2. Esters with even numbers of carbons prevailed, with C42, C44 and C46 favoured in the wild types, a predominance of C42 in cer2 and cer6 mutants, and a relative shift towards C46 in cer3 and cer23 mutants. The esters of all mutants and wild types were dominated by 16:0 acyl moieties, whereas the chain lengths of esterified alcohols were between C20 and C32. The alkyl chain‐length distributions of the wild‐type esters had a maximum for C28 alcohol, similar to the free alcohols accompanying them in the wax mixtures. The esterified alcohols of cer2, cer6 and cer9 had largely increased levels of C26 alcohol, closely matching the patterns of the corresponding free alcohols and, therefore, differing drastically from the corresponding wild type. In contrast, cer1, cer3, cer10, cer13 and cer22 showed ester alcohol patterns with increased levels of C30, only partially following the shift in chain lengths of the free alcohols in stem wax. These results provide information on the composition of substrate pools and/or the specificity of the ester synthase involved in wax ester formation. We conclude that alcohol levels at the site of biosynthesis are mainly limiting the ester formation in the Arabidopsis wild‐type epidermis.
Further in vivo studies on the role of the molecular chaperone, Hsp93, in plastid protein import
Authors: Kovacheva Sabina , Bédard Jocelyn , Wardle Anthony , Patel Ramesh , Jarvis Paul
Published: March 2007

In Arabidopsis, Hsp93 is encoded by two genes, atHSP93‐V and atHSP93‐III. We identified two T‐DNA mutants for atHSP93‐III: one being a partial ‘knockdown’ (hsp93‐III‐1) and the other a complete ‘knockout’ (hsp93‐III‐2). Homozygotes for both mutants were indistinguishable from wild type. We crossed each mutant to an atHSP93‐V knockout, and identified double mutants with strongly chlorotic phenotypes. This implied redundancy, which was confirmed by the complementation of mildly chlorotic hsp93‐V plants by atHSP93‐III over‐expression. While the hsp93‐V hsp93‐III‐1 mutant was doubly homozygous, the second double mutant was heterozygous for hsp93‐III‐2 (genotype: hsp93‐V/hsp93‐V; +/hsp93‐III‐2). Attempts to identify an hsp93‐V hsp93‐III‐2 double homozygote were unsuccessful, indicating that the Hsp93 pool is essential for viability. Consistently, siliques of the second double mutant contained aborted seeds (because of a block in the zygote–embryo transition) and failed ovules (because of a moderate defect in female gametophytes). Double‐mutant plants were chlorophyll‐deficient, contained under‐developed chloroplasts, and exhibited stunted growth. In import assays using a chimeric pre‐protein (plastocyanin transit peptide fused to dihydrofolate reductase; PC‐DHFR), a clear defect was observed in hsp93‐V hsp93‐III‐1 chloroplasts. Interestingly, while denaturation or stabilization of the DHFR moiety had a strong effect on import efficiency in the wild type, no such effects were observed with double‐mutant (or tic40) chloroplasts. This indicated that pre‐protein unfolding is not rate‐limiting for import into mutant chloroplasts, and suggested that (unlike the situation in mitochondria) the inner membrane import machinery does not contribute to pre‐protein unfolding at the organellar surface.
ROS production and protein oxidation as a novel mechanism for seed dormancy alleviation
Authors: Oracz Krystyna , Bouteau Hayat El‐Maarouf , Farrant Jill M. , Cooper Keren , Belghazi Maya , Job Claudette , Job Dominique , Corbineau Françoise , Bailly Christophe
Published: March 2007

At harvest, sunflower (Helianthus annuus L.) seeds are dormant and unable to germinate at temperatures below 15°C. Seed storage in the dry state, known as after‐ripening, is associated with an alleviation of embryonic dormancy allowing subsequent germination at suboptimal temperatures. To identify the process by which dormancy is broken during after‐ripening, we focused on the role of reactive oxygen species (ROS) in this phenomenon. After‐ripening entailed a progressive accumulation of ROS, namely superoxide anions and hydrogen peroxide, in cells of embryonic axes. This accumulation, which was investigated at the cellular level by electron microscopy, occurred concomitantly with lipid peroxidation and oxidation (carbonylation) of specific embryo proteins. Incubation of dormant seeds for 3 h in the presence of hydrogen cyanide (a compound that breaks dormancy) or methylviologen (a ROS‐generating compound) also released dormancy and caused the oxidation of a specific set of embryo proteins. From these observations, we propose a novel mechanism for seed dormancy alleviation. This mechanism involves ROS production and targeted changes in protein carbonylation patterns.
A reporter system for the individual detection of hydrogen peroxide and singlet oxygen: its use for the assay of reactive oxygen species produced in vivo
Authors: Shao Ning , Krieger‐Liszkay Anja , Schroda Michael , Beck Christoph F.
Published: March 2007

A reporter system for the assay of reactive oxygen species (ROS) was developed in Chlamydomonas reinhardtii, a plant model organism well suited for the application of inhibitors and generators of various types of ROS. This system employs various HSP70A promoter segments fused to a Renilla reniformis luciferase gene as a reporter. Transformants with the complete HSP70A promoter were inducible by both hydrogen peroxide and singlet oxygen. Constructs that lacked upstream heat‐shock elements (HSEs) were inducible by hydrogen peroxide, indicating that this induction does not require such HSEs. Rather, downstream elements located between positions −81 to −149 with respect to the translation start site appear to be involved. In contrast, upstream sequences are essential for the response to singlet oxygen. Thus, activation by singlet oxygen appears to require promoter elements that are different from those used by hydrogen peroxide. ROS generated endogenously by treatment of the alga with metronidazole, protoporphyrin IX, dinoterb or high light intensities were detected by this reporter system, and distinguished as production of hydrogen peroxide (metronidazole) and singlet oxygen (protoporphyrin IX, dinoterb, high light). This system thus makes it possible to test whether, under varying environmental conditions including the application of abiotic stress, hydrogen peroxide or singlet oxygen or both are produced.
Health‐related quality of life in children with hepatitis C acquired in the first year of life
Authors: Nydegger Andreas , Srivastava Anshu , Wake Melissa , Smith Arnold L , Hardikar Winita
Published: March 2007

Aims:  The first aim of this study was to determine the health‐related quality of life (HRQoL) of children with chronic hepatitis C virus (HCV) infection and compare HRQoL as reported by parents. The second aim was to ascertain parents' perceptions and concerns about current and future life for their child with HCV, and compare these findings with those reported by adolescents.

Methods:  The study group comprised children attending a tertiary pediatric HCV‐clinic in Melbourne, Australia, who acquired HCV prior to 12 months of age by vertical transmission or blood transfusion. Two validated (parent‐ and self‐reported) questionnaires of HRQoL were completed (CHQ‐PF 50 and CHQ‐CF 50). Scores for children with HCV were compared with normative data (representative sample of 3119 age‐matched Victorian children). A study‐designed questionnaire relating to the impact of the diagnosis of HCV on parent and child perceptions of current and future health was administered.

Results:  In total, 83% (19/23) questionnaires were returned. Physical and psychosocial summary scores were significantly lower in HCV than non‐HCV children (45.3 vs 49.6 and 44.0 vs 50.1, respectively). Nine out of 11 scale scores were significantly lower in children with HCV, most notably the General health (49.9 vs 77.1; P < 0.001) and Parent impact–emotional (45.6 vs 80.3; P < 0.001) scales. Children reported reduced physical functioning (82.8% vs 94.4%) but were otherwise less concerned than their parents about their future health.

Conclusions:  Despite being “asymptomatic” on routine medical history, children with early acquired HCV have significantly poorer health status than community controls. These findings suggest the need for services currently available for adult HCV patients to support families and children with HCV.
Oligonucleotide microarray: A new rapid method for screening the 23S rRNA gene of Helicobacter pylori for single nucleotide polymorphisms associated with clarithromycin resistance
Authors: Chen Shaohua , Li Youming , Yu Chaohui
Published: March 2007

Background and Aim:  Resistance to antibiotics in Helicobacter pylori is increasing and becoming a serious problem in eradication treatment. Resistance of H. pylori to clarithromycin has been found to be associated with 2142 A‐to‐G, 2143 A‐to‐G and 2182 C‐to‐T point mutations in the 23S rRNA gene. Thus, the purpose of the present study was to develop a new method to analyze single nucleotide polymorphism (SNPs) of 23S rRNA gene using oligonucleotide microarray and to determine the prevalence of each mutation in H. pylori‐positive patients.

Methods:  Gastric tissue biopsy specimens were obtained from patients undergoing upper gastrointestinal endoscopy. After DNA extraction, asymmetric PCR was employed to prepare single‐stranded target DNA labeled with a fluorescent dye. The PCR products that amplified a portion of 23S rRNA from H. pylori isolates were hybridized on DNA microarray, specific for SNP genotyping and mutation detection. The optimal signal intensity and efficiency of hybridization were observed for capture probes in the detection of DNA sequence variation. The relevant mutation was confirmed by DNA sequencing analysis.

Results:  Fifty‐four gastric biopsy specimens yielded H. pylori‐positive results and were studied to detect mutations in the 23S rRNA gene. There were no samples with A‐to‐G transition at position 2142. The 2143 A‐to‐G and 2182 C‐to‐T mutations were present in 11.11% and 12.96% of H. pylori strains examined, respectively. The relevant mutation was confirmed by analysis of DNA sequencing to be the same as that described at position 2142, 2143 and 2182 using oligonucleotide microarray.

Conclusions:  Oligonucleotide microarray of the PCR product permits a rapid and accurate screening of SNPs of 23S rRNA gene from H. pylori. It is now possible to apply this hybridization technology in clinical diagnosis and treatment.
Hepatic resection compared to percutaneous ethanol injection for small hepatocellular carcinoma using propensity score matching
Authors: Cho Yong Beom , Lee Kuhn Uk , Suh Kyung‐Suk , Kim Yoon Jun , Yoon Jung‐Hwan , Lee Hyo‐Suk , Hahn Seokyung , Park Byung‐Joo
Published: March 2007

Background:  Several surgical and non‐surgical therapeutic modalities have been used for the treatment of hepatocellular carcinoma (HCC). There have been several studies comparing hepatic resection (HR) and percutaneous ethanol injection (PEI) for the treatment of HCC. However, there is still disagreement about the best treatment modality.

Methods:  From 130 patients undergoing HR, 116 patients were individually matched to 116 controls from 249 patients undergoing PEI using propensity score matching to overcome possible biases in non‐randomized study. Survival analyses were undertaken to compare these propensity score‐matched groups.

Results:  After matching by propensity score, the major clinical outcomes in the HR (n = 116) and the PEI (n = 116) groups were found to be similar. The 1‐, 3‐ and 5‐year overall survival rates were higher in the HR group (94.8%, 76.5% and 65.6%) compared to the PEI group (95.7%, 73.5% and 49.3%) (P = 0.059). The cumulative 1‐, 3‐ and 5‐year disease‐free survival rates showed the same trend (HR: 76.1%, 50.6% and 40.6%; PEI: 62.6%, 25.5% and 19.1%) (P < 0.001). However, when stratified by Child–Pugh classification, it was no longer the case in the Child B patients. Single intrahepatic recurrence was the most common pattern of tumor recurrence after both treatments.

Conclusions:  Patients undergoing HR had a better survival profile than those undergoing PEI. However, when considering which technique to use for optimal HCC management, the individual patient's hepatic function must be considered.
Genetic polymorphisms of CD14 and Toll‐like receptor‐2 (TLR2) in patients with ulcerative colitis
Authors: Wang Fangyu , Tahara Tomomitsu , Arisawa Tomiyasu , Shibata Tomoyuki , Nakamura Masakatsu , Fujita Hiroshi , Iwata Masami , Kamiya Yoshio , Nagasaka Mitsuo , Takahama Kazuya , Watanabe Makoto , Hirata Ichiro , Nakano Hiroshi
Published: March 2007

Background and Aim:  Ulcerative colitis (UC) is a multifactorial disease resulting from a complex interaction of genetic and environmental factors. Identifying genetic variants that alter the innate immune response is highly relevant to understanding the pathogenesis of UC. The aim of this study was to investigate the association between CD14 and Toll‐like receptor‐2 (TLR2) genetic polymorphisms and chronic UC in Japanese patients.

Methods:  The study population consisted of 102 chronic UC patients and 146 healthy control subjects. Polymorphisms in the promoter at C‐260T of CD14 gene were investigated by PCR restriction fragment length polymorphism, and −196 to −174 del of TLR2 was investigated by allele‐specific PCR.

Results:  The frequencies of CD14 TT and T carrier were significantly higher in UC patients than in controls (TT: OR = 3.98, 95% CI 1.82–8.71, P = 0.0005; T carrier: OR = 2.98, 95% CI 1.47–6.01, P = 0.002). In addition, TT and T carrier were more closely associated with distal colitis phenotype (TT: OR = 7.78, 95% CI 2.14–28.28, P = 0.0007; T carrier: OR = 6.30, 95% CI 2.71–14.58, P = 0.005), onset after 20 years of age (TT: OR = 5.28, 95% CI 2.18–12.79; T carrier: OR = 3.79, 95% CI 1.67–8.59), chronic continuous type (TT: OR = 4.26, 95% CI 1.56–11.64; T carrier: OR = 3.09, 95% CI 1.33–7.82), and fewer than two hospitalizations (TT: OR = 4.44, 95% CI 1.81–10.89; T carrier: OR = 3.26, 95% CI 1.43–7.27). There was no significant difference in TLR2 –196 to −174 del/del and del/ins carrier frequencies between UC patients and healthy controls. However, these frequencies were significantly higher in steroid‐dependant patients than in controls (del/del: OR = 6.08, 95% CI 1.41–26.21; del carrier: OR = 3.00, 95% CI 1.13–7.98).

Conclusion:  The results suggest that existence of a mutation in the CD14 gene is associated with an increased susceptibility to developing UC, especially chronic continuous distal colitis phenotypes that develop after 20 years of age. Furthermore, polymorphism of TLR2 may be related to an increased risk of intensive types such as steroid‐dependent patients.
The influence of roller burnishing on the fatigue crack propagation in notched round bars—Experimental observations under three‐point bending
Authors: GARDIN C. , COURTIN S. , BERTHEAU D. , BÉZINE G. , BEN HADJ HAMOUDA H.
Published: March 2007

Roller burnishing involves a local plastic deformation on the surface that permits the fatigue strength of structures to be increased. Crack propagation is delayed by the introduction of compressive residual stresses. In this way, the process is particularly useful in the presence of stress concentrators, for example in the fillets of crankshafts or in notched shafts.

Crack propagation in round bars has been widely investigated, experimentally and numerically. However, the aim of the present work is to study roller burnished notched shafts (whose groove approaches the fillets of crankshafts) loaded in three‐point bending.

Experimentally, a sequence of destructive interrupted tests has been performed to obtain the crack kinetics and shapes during fatigue life. Thus, the beneficial influence of roller burnishing has been confirmed on both crack initiation and propagation. Some cracks were even stopped by compressive residual stresses. Otherwise, the crack shape observed was very original : cracks propagated first at the edge of the coupon and then, into the depth of the shaft. Multicracking and crack closure have been pointed out and appear to be of great importance.
Limit load analysis of strength undermatched welded T‐joints under bending
Authors: ALEXANDROV S. , KOÇAK M.
Published: March 2007

An increasing amount of laser beam welded T‐joints (e.g. skin‐stringer) of aluminium alloys are now in use in advanced fuselage applications designed as ‘integral structures’ for weight and cost savings. It is known that weld joints generally show lower strength (undermatching) than base metal in both laser beam and friction stir welded joints of 6xxx series Al‐alloys. Damage tolerance considerations in terms of the residual strength of such joints require limit load solutions to be used in engineering fitness‐for‐service (FFS) analysis. The paper, therefore, provides an upper bound limit load solution in closed form for welded T‐joints (idealized) with strength undermatching and subject to a bending moment. In addition to the necessary requirements of the upper bound theorem, the kinematically admissible velocity field chosen leads to a stress field, which satisfies the equilibrium equations and some stress boundary conditions in the plastic zone. This is an advantage of the solution and, therefore, it is expected that the upper bound obtained is close to the exact limit load of such joints.
Fatigue strength evaluation of the Japanese railway wheel
Authors: OKAGATA Y. , KIRIYAMA K. , KATO T.
Published: March 2007

For the purpose of evaluating the fatigue strength of the Japanese railway wheel, fatigue testing was done on the actual size wheel, using a new resonance‐type fatigue‐testing machine. Because the maximum stress under the horizontal and vertical loads occurs at the wheel plate, the fatigue strengths of the wheel plate were measured and the safety factors versus design load were evaluated. Two kinds of typical Japanese railway wheel were tested and the results showed that their safety factors were larger than 2.4.
Antipsychotic‐induced weight gain
Authors: Goudie A. J. , Cooper G. D. , Halford J. C. G.
Published: March 2007

Abstract:  Novel ‘atypical’ antipsychotic drugs represent a substantial improvement on older ‘typical’ drugs. However, clinical experience has shown that some, but not all, of these drugs can induce substantial weight gain. This interferes with compliance with drug taking and has expected effects on morbidity and mortality. In this review, we summarize current thinking on: (i) the extent to which different ‘atypical’ drugs induce weight gain; (ii) the possible roles of various neurotransmitters and neuropeptides in this adverse drug reaction; and (iii) the state of development of animal models in this area. We also outline major areas for future research.
The effect of pramlintide on hormonal, metabolic or symptomatic responses to insulin‐induced hypoglycaemia in patients with type 1 diabetes
Authors: Amiel S. A. , Heller S. R. , Macdonald I. A. , Schwartz S. L. , Klaff L. J. , Ruggles J. A. , Weyer C. , Kolterman O. G. , Maggs D. G.
Published: March 2007

Background:  Pramlintide, a human amylin analogue, is a potential new adjunctive therapy to insulin for patients with type 1 diabetes and insulin‐using patients with type 2 diabetes. Early clinical trials have shown a transient increased risk of hypoglycaemia in some patients at the time of initiating pramlintide therapy. This may be the result of combining the postprandial glucose, lowering effect of pramlintide with the existing hypoglycaemic potential of insulin without appropriate adjustment of insulin doses. However, the possibility that pramlintide may exert an independent detrimental effect on the physiological responses to insulin‐induced hypoglycaemia needs to be excluded.

Methods:  We conducted three separate randomized, placebo‐controlled studies in patients with type 1 diabetes treated with adjunctive pramlintide. These studies utilized pramlintide at high doses (either 0.1–1 mg pramlintide daily or 0.1–0.8 mg pramlintide four times a day for 5 or 6 days) as well as doses closer to those anticipated for therapeutic usage (30, 100 or 300 µg three times daily for 14 days), and examined the hormonal, metabolic and symptomatic responses to an insulin‐infusion hypoglycaemic challenge conducted at baseline and after days of therapy.

Results and conclusion:  Pramlintide had no effect on the counter‐regulatory hormonal, metabolic and symptomatic responses to hypoglycaemia. These findings demonstrated that pramlintide, when used as adjunctive therapy to insulin in patients with type 1 diabetes, has no independent effect on the response to hypoglycaemia.
Decreased insulin sensitivity is associated with the extent of coronary artery disease in patients with angina
Authors: Kwon K. , Choi D. , Koo B. K. , Ryu S. K.
Published: March 2007

Background:  Insulin resistance has been proposed as an important risk factor in the development of atherosclerosis.

Aim:  To evaluate the association of insulin resistance and coronary atherosclerosis, we investigated the correlation between insulin sensitivity and the degree of coronary stenosis in patients with angina pectoris.

Methods:  The study population consisted of 74 subjects with angina (54 men and 20 women) aged from 31 to 73 years. Coronary angiograms were evaluated by three semiquantitative scoring systems (vessel score, stenosis score and extent score) to estimate the extent of focal and diffuse coronary artery disease (CAD). Insulin sensitivity (KITT) was determined by the insulin tolerance test.

Results:  There were significant correlations existed between KITT and all three coronary scores. Multivariate analysis revealed significant and independent correlations of all three coronary scores with KITT (vessel score: β = −0.349, p = 0.004; stenosis score: β = −0.487, p < 0.001; extent score: β = −0.481, p < 0.001), even in patients without diabetes mellitus (vessel score: β = −0.387, p = 0.008; stenosis score: β = −0.469, p < 0.001; extent score: β = −0.559, p < 0.001). KITT was significantly lower in patient with diffuse CAD than without diffuse CAD (2.13 ± 0.66 vs. 2.57 ± 0.79%/min, p < 0.05). However, KITT was not different between patients with and without focal CAD.

Conclusions:  Insulin sensitivity has statistically significant and independent associations with the extent of coronary stenosis. These results suggest that insulin resistance may play a major role in the development of diffuse coronary artery stenosis.
Novel protein kinase C‐β isoform selective inhibitor JTT‐010 ameliorates both hyper‐ and hypoalgesia in streptozotocin‐ induced diabetic rats
Authors: Sasase T. , Yamada H. , Sakoda K. , Imagawa N. , Abe T. , Ito M. , Sagawa S. , Tanaka M. , Matsushita M.
Published: March 2007

Aim:  Activation of protein kinase C (PKC) is thought to play an important role in the pathogenesis of diabetic microvascular complications. PKC‐β is elevated in hyperglycaemic conditions, both in vivo and in vitro. In this study, pharmacological effects of a novel PKC‐β isoform selective inhibitor, JTT‐010 ((2R)‐3‐(2‐aminomethyl‐2,3‐dihydro‐1H‐3a‐azacyclopenta(a)inden‐8‐yl)‐4‐phenylaminopyrrole‐2,5‐dione monomethanesulphonate), on diabetic neuropathy were examined.

Methods:  PKC inhibitory activity of JTT‐010 was evaluated with an enzyme assay. For the in vivo study, streptozotocin (STZ)‐induced diabetic rats were treated with JTT‐010 for 12 weeks and tail/sciatic nerve conduction velocity (NCV) evaluated. Hyper/hypoalgesia was evaluated using tail‐flick and formalin tests.

Results:  JTT‐010 inhibited PKC‐βI and ‐βII with IC50 values of 4.0 and 2.3 nm respectively. For other PKC isoforms, IC50 values were 54 nm or greater. In STZ‐induced diabetic rats showing a reduction in tail/sciatic nerve conduction velocities, JTT‐010 (0.3–3 mg/kg) ameliorated the reduction of these velocities. In a formalin test, STZ‐induced diabetic rats had hyperalgesia in the first phase. JTT‐010 reduced nociceptive response at doses of 0.1 mg/kg or higher. Furthermore, STZ‐induced diabetic rats showed hypoalgesia in the second phase of the formalin test and tail‐flick test. JTT‐010 also ameliorates these symptoms at doses of 0.1 mg/kg or higher.

Conclusions:  These observations suggest that PKC‐β contributes not only to diabetic hyperalgesia, but also to hypoalgesia and also contributes to defects in NCV. PKC‐β inhibitor, JTT‐010, may be beneficial in suppressing the development of diabetic nerve dysfunction, including hyperalgesia and hypoalgesia.
Oxidized LDL and small LDL particle size are independently predictive of a selective defect in microcirculatory endothelial function in type 2 diabetes
Authors: Woodman R. J. , Watts G. F. , Playford D. A. , Best J. D. , Chan D. C.
Published: March 2007

Aim:  To explore the associations of LDL (low‐density lipoprotein) particle size and oxidized LDL with endothelium‐dependent function of the forearm microcirculation in diabetes.

Methods:  Endothelium‐dependent function was examined in 43 middle‐aged men and women with type 2 diabetes and 10 age‐matched controls. All received aspirin to inhibit endothelial cyclo‐oxygenase. Forearm blood flow (FBF) was measured using venous occlusion plethysmography with separate administration of acetylcholine (ACh) and bradykinin (BK) into the brachial artery. Endothelium‐independent function was assessed using sodium nitroprusside (SNP). NG‐monomethyl‐L‐arginine (L‐NMMA) was co‐infused with ACh (ACh + L‐NMMA) and BK (BK + L‐NMMA) to assess non–NO‐mediated contributions to endothelium‐dependent function.

Results:  Subjects with diabetes had impaired endothelium‐dependent and endothelium‐independent function compared with controls (p < 0.01 for ACh, BK and SNP). In multivariate regression analysis, LDL size (r = 0.41 and p = 0.007), oxidized LDL (r = −0.41 and p = 0.007) and duration of diabetes (r = −0.37 and p = 0.02) predicted FBF response to ACh independently of age, gender and systolic blood pressure. There were no associations between LDL size, oxidized LDL, duration of diabetes and FBF response to BK, SNP, ACh + L‐NMMA or BK + L‐NMMA.

Conclusion:  In type 2 diabetes, small dense LDL particles, duration of diabetes and oxidized LDL may independently contribute to endothelial dysfunction of the microcirculation. These disturbances may occur via a selective defect, because ACh and BK activate endothelial NO synthase via different G‐protein signal transduction pathways.
Alanine aminotransferase and the 6‐year risk of the metabolic syndrome in Caucasian men and women: the Hoorn Study
Authors: Schindhelm R. K. , Dekker J. M. , Nijpels G. , Stehouwer C. D. A. , Bouter L. M. , Heine R. J. , Diamant M.
Published: March 2007

Aims  To study the association between alanine aminotransferase (ALT) and the 6‐year risk of the metabolic syndrome in a population‐based study in Caucasian men and women.

Methods  The association of ALT with the 6‐year risk of the metabolic syndrome in 1097 subjects, aged 50–75 years, was assessed in the Hoorn Study with logistic regression analysis. Subjects with the metabolic syndrome at baseline, defined according to the Adult Treatment Panel III of the National Cholesterol Education Program, were excluded.

Results  After 6.4 (range 4.4–8.1) years follow‐up, 226 subjects (20.6%) had developed the metabolic syndrome. The odds ratio (95% confidence interval) for developing the metabolic syndrome, adjusted for age, sex, alcohol intake and follow‐up duration was 2.25 (1.50–3.37) for subjects in the upper tertile compared with those in the lower tertile of ALT. This association persisted after additional adjustment for all the baseline metabolic syndrome features [1.62 (1.02–2.58)]. Among the individual components of the metabolic syndrome, ALT was significantly associated only with fasting plasma glucose at follow‐up.

Conclusions  These data suggest that ALT is associated with risk of the metabolic syndrome in a general population of middle‐aged Caucasian men and women, further strengthening the role of ALT as an indicator for future metabolic derangement. These findings warrant further studies to elucidate the role of non‐adipose tissue fat accumulation in the pathogenesis of complications related to the metabolic syndrome.

Diabet. Med. 24, 430 – 435 (2007)
The accuracy of cystatin C and commonly used creatinine‐based methods for detecting moderate and mild chronic kidney disease in diabetes
Authors: MacIsaac R. J. , Tsalamandris C. , Thomas M. C. , Premaratne E. , Panagiotopoulos S. , Smith T. J. , Poon A. , Jenkins M. A. , Ratnaike S. I. , Power D. A. , Jerums G.
Published: March 2007

Background  The accuracy of measuring serum cystatin C levels for detecting various stages of chronic kidney disease (CKD) in diabetes is still unclear.

Methods  In a cross‐sectional study of 251 subjects, a reference glomerular filtration rate (GFR) was measured using 99cTc‐DTPA plasma clearance (iGFR). Multivariate analysis was used to identify independent clinical and biochemical associations with serum cystatin C and iGFR levels. The diagnostic accuracy of cystatin C and commonly used creatinine‐based methods of measuring renal function (serum creatinine, the MDRD four‐variable and Cockcroft–Gault formulae) for detecting mild and moderate CKD was also compared.

Results  In the entire study population the same five variables, age, urinary albumin excretion rates, haemoglobin, history of macrovascular disease and triglyceride levels were independently associated with both cystatin C and iGFR levels. A serum cystatin C level cut‐off > 82.1 nmol/l (1.10 mg/l) had the best test characteristics as a screening tool for detecting moderate CKD (< 60 ml/min per 1.73 m2) when compared with creatinine‐based methods. At the upper threshold for mild CKD (< 90 ml/min per 1.73 m2), cystatin C also had greater diagnostic accuracy than creatinine, but had similar diagnostic accuracy when compared with creatinine‐based formulae for predicting renal function.

Conclusions  This study suggests that the clinical and biochemical parameters associated with serum cystatin C levels are closely linked to those associated with GFR and highlights the potential usefulness of screening for moderate or mild CKD in subjects with diabetes by simply measuring serum cystatin C levels.
Geographical and environmental range expansion through polyploidy in wild potatoes (SolanumsectionPetota)
Authors: Hijmans Robert J. , Gavrilenko Tatjana , Stephenson Sarah , Bamberg John , Salas Alberto , Spooner David M.
Published: March 2007

Aim To assess evidence for geographical and environmental range expansion through polyploidy in wild potatoes (Solanumsect.Petota). There are diploids, triploids, tetraploids, pentaploids and hexaploids in this group.

Location Wild potatoes occur from the south‐western USA (Utah and Colorado), throughout the tropical highlands of Mexico, Central America and the Andes, to Argentina, Chile and Uruguay.

Methods We compiled 5447 reports of ploidy determination, covering 185 of the 187 species, of which 702 determinations are presented here for the first time. We assessed the frequency of cytotypes within species, and analysed the geographical and climatic distribution of ploidy levels.

Results Thirty‐six per cent of the species are entirely or partly polyploid. Multiple cytotypes exist in 21 species, mostly as diploid and triploid, but many more may await discovery. We report the first chromosome count (2n= 24) forSolanum hintonii. Diploids occupy a larger area than polyploids, but diploid and tetraploid species have similar range sizes, and the two species with by far the largest range sizes are tetraploids. The fraction of the plants that are polyploids is much higher from Mexico to Ecuador than farther south. Compared with diploids, triploids tend to occur in warmer and drier areas, whereas higher‐level polyploids tend to occur in relatively cold areas. Diploids are absent from Costa Rica to southern Colombia, the wettest part of the group's range.

Main conclusions These results suggest that polyploidy played an important role in this group's environmental differentiation and range expansion.