bluuebunny/crossref_metadata_2025 huggingface dataset:
Racemic epinephrine compared to salbutamol in hospitalized young children with bronchiolitis; a randomized controlled clinical trial [ISRCTN46561076]
Authors: Langley Joanne M , Smith Michael B , LeBlanc John C , Joudrey Heather , Ojah Cecil R , Pianosi Paul
Published: May 2005

Background

Bronchiolitis is the most common cause of lower respiratory tract illness in infancy, and hospital admission rates appear to be increasing in Canada and the United States. Inhaled beta agonists offer only modest short-term improvement. Trials of racemic epinephrine have shown conflicting results. We sought to determine if administration of racemic epinephrine during hospital stay for bronchiolitis improved respiratory distress, was safe, and shortened length of stay.

Methods

The study was a randomized, double-blind controlled trial of aerosolized racemic epinephrine compared to salbutamol every one to 4 hours in previously well children aged 6 weeks to ≤ 2 years of age hospitalized with bronchiolitis. The primary outcome was symptom improvement as measured by the Respiratory Distress Assessment Instrument (RDAI); secondary outcomes were length of stay in hospital, adverse events, and report of symptoms by structured parental telephone interview one week after discharge.

Results

62 children with a mean age of 6.4 months were enrolled; 80% of children had Respiratory Syncytial Virus (RSV). Racemic epinephrine resulted in significant improvement in wheezing and the total RDAI score on day 2 and over the entire stay (p < 0.05). The mean LOS in the epinephrine arm was 2.6 days (95% CI 2, 3.2) v. 3.4 days in those in the salbutamol group (95% CI 2.6, 4.2) (p > 0.05). Adverse events were not significantly different in the two arms. At one week post-discharge, over half of parents reported that their child still had a respiratory symptom and 40% had less than normal feeding.

Conclusion

Racemic epinephrine relieves respiratory distress in hospitalized infants with bronchiolitis and is safe but does not abbreviate hospital stay. Morbidity associated with bronchiolitis as identified by parents persists for at least one week after hospital discharge in most infants.
The tissue microarray data exchange specification: A document type definition to validate and enhance XML data
Authors: Nohle David G , Ayers Leona W
Published: May 2005

Background

The Association for Pathology Informatics (API) Extensible Mark-up Language (XML) TMA Data Exchange Specification (TMA DES) proposed in April 2003 provides a community-based, open source tool for sharing tissue microarray (TMA) data in a common format. Each tissue core within an array has separate data including digital images; therefore an organized, common approach to produce, navigate and publish such data facilitates viewing, sharing and merging TMA data from different laboratories. The AIDS and Cancer Specimen Resource (ACSR) is a HIV/AIDS tissue bank consortium sponsored by the National Cancer Institute (NCI) Division of Cancer Treatment and Diagnosis (DCTD). The ACSR offers HIV-related malignancies and uninfected control tissues in microarrays (TMA) accompanied by de-identified clinical data to approved researchers. Exporting our TMA data into the proposed API specified format offers an opportunity to evaluate the API specification in an applied setting and to explore its usefulness.

Results

A document type definition (DTD) that governs the allowed common data elements (CDE) in TMA DES export XML files was written, tested and evolved and is in routine use by the ACSR. This DTD defines TMA DES CDEs which are implemented in an external file that can be supplemented by internal DTD extensions for locally defined TMA data elements (LDE).

Conclusion

ACSR implementation of the TMA DES demonstrated the utility of the specification and allowed application of a DTD to validate the language of the API specified XML elements and to identify possible enhancements within our TMA data management application. Improvements to the specification have additionally been suggested by our experience in importing other institution's exported TMA data. Enhancements to TMA DES to remove ambiguous situations and clarify the data should be considered. Better specified identifiers and hierarchical relationships will make automatic use of the data possible. Our tool can be used to reorder data and add identifiers; upgrading data for changes in the specification can be automatically accomplished. Using a DTD (optionally reflecting our proposed enhancements) can provide stronger validation of exported TMA data.
The first case of septicemia due to nontoxigenic Corynebacterium diphtheriae in Poland: case report
Authors: Zasada Aleksandra Anna , Zaleska Maria , Podlasin Regina Beata , Seferyńska Ilona
Published: May 2005

Background

Toxigenic strains of Corynebacterium diphtheriae are well known agent of diphtheria. Nontoxigenic strains can cause atypical course of the disease. Invasive diseases caused by C. diphtheriae occur very rare.

Case presentation

We have described the first case of septicemia and endocarditis due to nontoxigenic C. diphtheriae biotype gravis in Poland. The patient has not belonged to any group of risk such infection.

Conclusion

The case presented in this article shows unusual case of infection connected with nontoxigenic C. diphtheriae that took place in the area where have been no cases of diphtheria and other C. diphtheriae infections for near ten years. It shows the importance of identifying Corynebacterium isolates at the species level especially when the strain has been isolated from normally sterile sites.
Amplification and overexpression of the ID4 gene at 6p22.3 in bladder cancer
Authors: Wu Qiong , Hoffmann Michèle J , Hartmann Florian H , Schulz Wolfgang A
Published: May 2005

Background

Amplifications at 6p22.3 are prevalent in advanced stage bladder cancer (TCC). Previous studies have identified SOX4, CDKAL, and E2F3 as targets of this amplification and therefore potential oncogenes, but the more telomeric DEK gene too has been reported as overexpressed and amplified. We have therefore investigated whether the intermediate region harboring the oncogene candidate ID4 is also part of the amplicon.

Results

Expression of E2F3, DEK, and ID4 was investigated by real-time RT-PCR in 28 TCC compared to 6 normal bladder tissues and in 15 TCC cell lines compared to cultured normal urothelial cells. Expression of E2F3 as well as DEK increased on average in tumor vs. normal tissues (3-fold and 2.5-fold, resp.), but only the increase for E2F3 was statistically significant (p = 0.039). ID4 overexpression was observed in selected specimens. Each of the three genes was overexpressed in several cell lines, up to 150-fold (ID4), 30-fold (E2F3), and 9-fold (DEK), but these increases were not correlated to each other. Instead, moderate (DEK) to excellent (ID4) correlations were observed with copy number increases of microsatellites near each gene. Microsatellite copy number increases were highly heterogeneous across the investigated several Mb region revealing at least three subregions of amplification.

Conclusion

Extending previous reports, our data indicate that the 6p22.3 amplicon in TCC is highly heterogeneous and targets several genes in a variable fashion. Among these, expression of E2F3 and DEK appear to be generally increased in TCC, with additional increases caused by amplifications. In contrast, over-expression of ID4, which is normally predominantly expressed in testes and brain, appears to depend more strictly on gene amplification. Accordingly, the effect of amplifications at 6p22.3 in bladder cancer is expected to be non-uniform, thereby contributing to the highly variable biological and clinical behavior of advanced stage tumors. ID4 is a potential oncogene in a small subset of bladder cancers.
Early Menarche and the Development of Cardiovascular Disease Risk Factors in Adolescent Girls: The Fels Longitudinal Study
Authors: Remsberg Karen E. , Demerath Ellen W. , Schubert Christine M. , Chumlea Wm. Cameron , Sun Shumei S. , Siervogel Roger M.
Published: May 2005

The purpose of this study was to evaluate the influence of menarcheal age on changes in insulin, glucose, lipids, and blood pressure during adolescence and to assess whether body composition modifies this relationship. We examined 391 girls, a subset of Fels Longitudinal Study female participants (8–21 yr of age). Self-reported menarcheal age was classified based on the National Health and Nutrition Examination Survey III distribution, in which early menarche was at the 25th percentile or less (11.9 yr). Age at menarche was examined in relation to measures of body composition [e.g. fat-free mass (FFM) and percent body fat (PBF)], insulin resistance, blood pressure, and lipid profile. The effects of menarcheal age and body composition on cardiovascular disease risk factor changes were analyzed with serial data mixed models. Median menarcheal age was 12.7 yr (range, 9.8–17.0 yr), with 91 girls (23%) classified as early menarche. Girls with early menarche had more deleterious changes in insulin, glucose, blood pressure, FFM, and PBF levels than girls with average or late menarche. Menarcheal age adversely affected cardiovascular disease risk factor changes independent of age and changes in FFM or PBF. Girls with early menarche exhibited elevated blood pressure and glucose intolerance compared with later maturing girls, independent of body composition.
Estrogen Replacement Therapy Increases Plasma Ghrelin Levels
Authors: Kellokoski Eija , Pöykkö Seppo M. , Karjalainen Anna H. , Ukkola Olavi , Heikkinen Jorma , Kesäniemi Y. Antero , Hörkkö Sohvi
Published: May 2005

Ghrelin is a novel peptide hormone that has GH releasing activity and also other endocrine and metabolic functions. The purpose of this study was to investigate the effects of estrogen replacement therapy on plasma active ghrelin levels in 64 hysterectomized postmenopausal women receiving peroral estrogen (PE) or transdermal estrogen therapy for 6 months. Active ghrelin was measured using commercial RIA. Estrogen therapy increased plasma active ghrelin from 479 ± 118 to 521 ± 123 pg/ml (P = 0.002) among all the study subjects. PE therapy increased plasma ghrelin levels from 465 ± 99 to 536 ± 104 pg/ml (P = 0.001). Transdermal estrogen therapy did not increase plasma ghrelin levels significantly (from 491 ± 132 to 509 ± 138 pg/ml; P = 0.332). The relative changes in plasma ghrelin levels were associated with the relative changes in serum estradiol concentrations (r = 0.299; P = 0.017). During the estrogen therapy, negative associations were found between plasma active ghrelin levels and several plasma lipids (total cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, total triglycerides, and very low-density lipoprotein triglycerides). As a conclusion, estrogen replacement therapy increased active plasma ghrelin levels, particularly PE therapy. Additional studies are needed to determine the possible underlying mechanisms.
Cyclooxygenase Inhibitors Suppress Aromatase Expression and Activity in Breast Cancer Cells
Authors: Díaz-Cruz Edgar S. , Shapiro Charles L. , Brueggemeier Robert W.
Published: May 2005

Estradiol is biosynthesized from androgens by the aromatase enzyme complex. Previous studies suggest a strong association between aromatase (CYP19) gene expression and the expression of cyclooxygenase (COX) genes. Our hypothesis is that higher levels of COX-2 expression result in higher levels of prostaglandin E2, which, in turn, increases CYP19 expression through increases in intracellular cAMP levels. This biochemical mechanism may explain the beneficial effects of nonsteroidal antiinflammatory drugs on breast cancer. The effects of nonsteroidal antiinflammatory drugs, COX-1 and COX-2 selective inhibitors on aromatase activity and expression were studied in human breast cancer cells. The data from these experiments revealed dose-dependent decreases in aromatase activity after treatment with all agents. Real-time PCR analysis of aromatase gene expression showed a significant decrease in mRNA levels when compared with control for all agents. These results were consistent with enzyme activity data, suggesting that the effect of COX inhibitors on aromatase begins at the transcriptional level. Exon-specific real-time PCR studies suggest that promoters I.3, I.4, and II are involved in this process. Thus, COX inhibitors decrease aromatase mRNA expression and enzymatic activity in human breast cancer cells in culture, suggesting that these agents may be useful in suppressing local estrogen biosynthesis in the treatment of hormone-dependent breast cancer.
In Vitro Coexpression and Pharmacological Rescue of Mutant Gonadotropin-Releasing Hormone Receptors Causing Hypogonadotropic Hypogonadism in Humans Expressing Compound Heterozygous Alleles
Authors: Leaños-Miranda Alfredo , Ulloa-Aguirre Alfredo , Janovick Jo Ann , Conn P. Michael
Published: May 2005

We analyzed the function of mutant GnRH receptor (GnRHR) pairs associated with compound heterozygous patients showing complete or partial forms of hypogonadotropic hypogonadism. We did this to examine potential interactions between misfolded mutants that may influence net receptor function and response to pharmacological rescue. Nine pairs of GnRHR mutants and an unreported combination (L314X(stop)/R262Q) were studied. Coexpression of each pair of mutants in COS-7 cells resulted in an active predominant effect (Q106R/L266R, A171T/Q106R, T32I/C200Y, and R262Q/A129D mutant GnRHR pairs), an additive effect (R262Q/Q106R, N10K/Q106R, and R262Q/Y284C human GnRHR pairs), or a dominant-negative effect (L314X(stop)/Q106R, Q106R+S217R/R262Q, and L314X(stop)/R262Q GnRHRs). For all combinations, addition of the pharmacoperone IN3 increased both agonist binding and effector coupling. The IN3 response was unpredictable because responses could be either similar, higher, or lower, compared with that exhibited by the less affected mutant. The clinical phenotype in patients expressing complex heterozygous alleles appears to be dictated by both the contribution from each mutant and a dominant-negative effect similar to that reported for mutants and wild-type receptor. Depending on the genotype, partial or full restoration of receptor function in response to pharmacological chaperones may be achievable goals in patients bearing inactivating mutations in the GnRHR gene.
A Pilot Study of Combined Suicide/Cytokine Gene Therapy in Two Patients with End-Stage Anaplastic Thyroid Carcinoma
Authors: Barzon Luisa , Pacenti Monia , Taccaliti Augusto , Franchin Elisa , Bruglia Matteo , Boscaro Marco , Palù Giorgio
Published: May 2005

This study represents the first report of gene therapy for anaplastic thyroid carcinoma, one of the most aggressive solid tumors in humans. Two patients with end-stage anaplastic thyroid carcinoma were treated by direct intratumor injection of retroviral vector producer cells followed by ganciclovir. The retroviral vector carried the human IL-2 gene and the suicide gene thymidine kinase of herpes simplex virus type 1. Treatment was safe and associated with only mild adverse events. Transduction of tumor cells and production of T helper type 1 cytokines was demonstrated in tumor biopsies. Gene therapy led also to a marked increase in T helper type 1 cytokine expression in peripheral blood mononuclear cells. Radiological evaluation of injected tumor masses demonstrated local tumor necrosis.
Fasting Ghrelin Levels Are Not Elevated in Children with Hypothalamic Obesity
Authors: Kanumakala S. , Greaves R. , Pedreira C. C. , Donath S. , Warne G. L. , Zacharin M. R. , Harris M.
Published: May 2005

Morbid obesity is a common problem after damage to the hypothalamus. Hypothalamic dysfunction is also thought to underlie the obesity that is typical of Prader-Willi syndrome. Elevated fasting levels of the appetite-stimulating hormone ghrelin have been reported in Prader-Willi syndrome. The aim of this study was to determine whether fasting ghrelin levels are increased in children with hypothalamic obesity.

Fasting total ghrelin levels were compared in three groups: normal-weight controls (n = 16), obese controls (n = 16), and patients with hypothalamic obesity (n = 16). Obese children had lower fasting total ghrelin levels than normal controls, but there was no difference between the fasting total ghrelin level in obese controls and children with hypothalamic obesity (P = 0.88). These data suggest that it is unlikely that an elevation in fasting total ghrelin is responsible for the obesity that occurs after hypothalamic damage. Therapeutic interventions aimed at reducing fasting total ghrelin may prove ineffective in controlling weight gain in this group.
Identification of Pax2-regulated genes by expression profiling of the mid-hindbrain organizer region
Authors: Bouchard Maxime , Grote David , Craven Sarah E. , Sun Qiong , Steinlein Peter , Busslinger Meinrad
Published: May 2005

The paired domain transcription factor Pax2 is required for the formation of the isthmic organizer (IsO) at the midbrain-hindbrain boundary, where it initiates expression of the IsO signal Fgf8. To gain further insight into the role of Pax2 in mid-hindbrain patterning, we searched for novel Pax2-regulated genes by cDNA microarray analysis of FACS-sorted GFP+ mid-hindbrain cells from wild-type and Pax2–/– embryos carrying a Pax2GFP BAC transgene. Here, we report the identification of five genes that depend on Pax2 function for their expression in the mid-hindbrain boundary region. These genes code for the transcription factors En2 and Brn1 (Pou3f3), the intracellular signaling modifiers Sef and Tapp1, and the non-coding RNA Ncrms. The Brn1 gene was further identified as a direct target of Pax2, as two functional Pax2-binding sites in the promoter and in an upstream regulatory element of Brn1were essential for lacZ transgene expression at the mid-hindbrain boundary. Moreover, ectopic expression of a dominant-negative Brn1 protein in chick embryos implicated Brn1 in Fgf8 gene regulation. Together,these data defined novel functions of Pax2 in the establishment of distinct transcriptional programs and in the control of intracellular signaling during mid-hindbrain development.
The boundary cap: a source of neural crest stem cells that generate multiple sensory neuron subtypes
Authors: Hjerling-Leffler Jens , Marmigère Frédéric , Heglind Mikael , Cederberg Anna , Koltzenburg Martin , Enerbäck Sven , Ernfors Patrik
Published: May 2005

The boundary cap (BC) is a transient neural crest-derived group of cells located at the dorsal root entry zone (DREZ) that have been shown to differentiate into sensory neurons and glia in vivo. We find that when placed in culture, BC cells self-renew, show multipotency in clonal cultures and express neural crest stem cell (NCSCs) markers. Unlike sciatic nerve NCSCs,the BC-NCSC (bNCSCs) generates sensory neurons upon differentiation. The bNCSCs constitute a common source of cells for functionally diverse types of neurons, as a single bNCSC can give rise to several types of nociceptive and thermoreceptive sensory neurons. Our data suggests that BC cells comprise a source of multipotent sensory specified stem cells that persist throughout embryogenesis.
Sources of mechanical power for uphill running in humans
Authors: Roberts Thomas J. , Belliveau Richard A.
Published: May 2005

During uphill running limb muscles must perform net mechanical work to increase the body's potential energy, while during level running the net mechanical work required is negligible as long as speed is constant. The increased demands for work as running incline increases might be met by an increase in power output at all joints, or only a subset of joints. We used inverse dynamics to determine which joints modulate net work output in humans running uphill. We measured joint kinematics and ground reaction force during moderate speed running at 0°, 6° and 12° inclines. Muscle force,joint power and work per step were determined at the ankle, knee and hip using inverse dynamics calculations. We found that virtually all of the increase in work output with increasing incline resulted from increases in net work done at the hip (-0.25±0.23 J kg-1, level, vs0.88±0.10 J kg-1, 12° incline), while the knee and ankle performed similar functions at all inclines. The increase in work output at the hip resulted primarily from a large increase in average net muscle moment during stance (2.07±17.84 Nm, level, vs 87.30±13.89 Nm,12° incline); joint excursion increased by only 20%(41.22±3.41°, level, vs 49.22±2.35°, 12°incline). The increase in hip muscle moment and power was associated with a poorer mechanical advantage for producing force against the ground. The increase in hip moment with running incline allows for the production of the power necessary to lift the body. This power may be developed by hip extensors or by transfer of power from muscles at other joints via biarticular muscles.
Timing of praying mantis evasive responses during simulated bat attack sequences
Authors: Triblehorn Jeffrey D. , Yager David D.
Published: May 2005

Praying mantids perform evasive maneuvers that vary with the level of danger posed by their bat predators. The vocalization pattern of attacking bats provides cues that mantids can potentially use to decide how and when to respond. Using pulse trains simulating bat attack echolocation sequences, this study determines when in the attack sequence the mantis power dive (its response to high-level threat) occurs and predicts the parameters within the echolocation sequence that are important for eliciting the response. For sequences with a rapid transition from low to high pulse repetition rates(PRRs), the evasive response occurred close to the point during the simulated sequence when the bat would have contacted the mantis. However, the evasive response occurred earlier if the transition was gradual. Regardless of the transition type, the prediction data show that sequences trigger the response when PRRs reach 20-40 pulses s-1. These results suggest that a bat gradually increasing its PRR could `tip off' the mantis, enabling it to escape. Attack sequences contain gradual transitions when bats engage in strobing behavior, an echolocation phenomenon that may help the bat perceive the auditory scene. Conversely, bat attack sequences that contain rapid increases in PRR close to the point of capture could circumvent the mantid's auditory defense. Based on these findings, mantids as well as other insects could benefit from having a back-up defense response to offset any advantage the bat gains by rapidly switching from low to high PRRs.
Genomic sequences encoding two types of medaka hemopexin-like protein Wap65, and their gene expression profiles in embryos
Authors: Nakaniwa Makiko , Hirayama Makoto , Shimizu Atsushi , Sasaki Takashi , Asakawa Shuichi , Shimizu Nobuyoshi , Watabe Shugo
Published: May 2005

Medaka genomic BAC clones, which contained two types of medaka hemopexin-like protein gene (Wap65), mWap65-1 and mWap65-2, were screened and their genomic sequences were determined by the shotgun strategy. The exon-intron organizations were highly conserved between both mWap65s and human hemopexin genes. The 5′-flanking regions of mWap65-1 and mWap65-2 contained various putative transcription factor binding sites including elements for developmental regulation. The expression patterns of mWap65s during embryonic development were examined by quantitative real-time PCR, demonstrating that both mWap65 transcripts were observed in early embryonic stages, but their expression patterns were different. Interestingly, in situhybridization revealed that mWap65-2 transcripts were restricted to liver, whereas mWap65-1 transcripts were detected along the edge of pectoral fin buds and the median fin fold of tail buds in embryos at stage 32. Furthermore, we generated transgenic medaka expressing GFP driven by mWap65-1 and mWap65-2 promoters and observed GFP expression patterns during ontogeny. Although localizations of GFP varied among individuals, embryos uniformly expressed GFP 1 day after injection of mWap65-1-hrGFP and mWap65-2-hrGFP constructs, suggesting that mWap65-1 and mWap65-2 promoters were activated in very early stages. The differences between mWap65-1 and mWap65-2in their expression profiles indicate their distinct roles during ontogeny.
Arterial hemodynamics and mechanical properties after circulatory intervention in the chick embryo
Authors: Lucitti Jennifer L. , Tobita Kimimasa , Keller Bradley B.
Published: May 2005

Altered blood pressure and flow impact cardiac function during morphogenesis. How the arterial system supports cardiac morphogenesis after circulatory disruptions is not well characterized. We manipulated arterial flow via left atrial ligation (LAL) or arterial load viaright vitelline artery ligation (VAL) in Hamburger-Hamilton (HH) stage 21 chick embryos. Embryos were reincubated for 1 h (HH21), 14 h (HH24) or 30 h(HH27). At each stage we measured simultaneous dorsal aortic blood pressure and flow, and calculated arterial compliance, impedance and hydraulic power. LAL acutely reduced stroke volume (Vs), cardiac output(Q̇) and hydraulic power. Arterial pressure was preserved by a compensatory increase in characteristic impedance and decrease in compliance. Impedance parameters and compliance normalized by HH24 and all parameters normalized by HH27. VAL acutely increased arterial resistance. Embryos maintained arterial pressure by decreasing Vs and Q̇. These parameters remained altered through HH27. In summary, despite the intervention, compensatory alterations in Vs and arterial resistance maintained arterial pressure and fraction of oscillatory power within a narrow range. These results suggest that the maintenance of arterial pressure and circulatory energy efficiency, but not arterial flow, is critical to embryogenesis.
Appetite-suppressing effects of ammonia exposure in rainbow trout associated with regional and temporal activation of brain monoaminergic and CRF systems
Authors: Ortega Van A. , Renner Kenneth J. , Bernier Nicholas J.
Published: May 2005

To assess whether the brain's monoaminergic and/or corticotropin-releasing factor (CRF) systems may be involved in mediating the appetite-suppressing effects of high environmental ammonia levels, we exposed rainbow trout to one of four NH4Cl treatments (0, 500, 750 1000 μmol l-1)for 24 or 96 h and monitored changes in food intake, brain serotonin (5-HT)and dopamine (DA) activity, CRF and urotensin I (UI) mRNA levels, and plasma cortisol levels. Food intake decreased in a dose-dependent manner after 24 h of ammonia exposure and partially recovered in all groups after 96 h. Ammonia also elicited dose-dependent increases in serotonergic activity in the hypothalamus (HYP), telencephalon (TEL) and posterior brain (PB). Whereas the increase in serotonergic activity was timed with the 24 h food intake inhibition, TEL and PB serotonergic activity increased after 96 h. In the PB,exogenous ammonia also elicited dose-dependent increases in dopaminergic activity after both 24 and 96 h of exposure. Transient increases in TEL CRF and UI mRNA levels, HYP UI mRNA levels, and plasma cortisol concentrations were evidence that the hypothalamic-pituitary-interrenal (HPI) stress axis was primarily stimulated in the first 24 h of ammonia exposure when food intake was depressed. Overall, the transient nature of the appetite suppression during chronic ammonia exposure, and the time-dependent changes in brain monoaminergic and CRF systems, implicate 5-HT, DA, CRF and UI as potential mediators of the appetite-suppressing effects of ammonia. Among these anorexigenic signals, our results specifically identify hypothalamic 5-HT as a potentially key neurobiological substrate for the regulation of food intake during exposure to high external ammonia concentrations.
Linking swimming performance, cardiac pumping ability and cardiac anatomy in rainbow trout
Authors: Claireaux Guy , McKenzie David J. , Genge A. Gaylene , Chatelier Aurélien , Aubin Joël , Farrell Anthony P.
Published: May 2005

We exploited the inherent individual diversity in swimming performance of rainbow trout Oncorhynchus mykiss to investigate the hypothesis that maximum cardiac performance is linked to active metabolic rate (AMR) and critical swimming speed (Ucrit). Six hundred juveniles(body mass ∼150 g) were screened using a swimming challenge of 1.2 m s-1 to identify `poor swimmers' and `good swimmers', i.e. the first and last 60 fish to fatigue, respectively. These 120 fish were individually tagged and then reared in common tanks for 9 months, where they grew at similar rates and achieved a similar body mass of approximately 1100 g. Critical swimming speed (Ucrit) was then measured individually in tunnel respirometers, with simultaneous recordings of cardiac output via a ventral aortic flow probe. The group of individuals that were screened as poor swimmers remained so, with a significantly (27%) lower Ucrit than good swimmers [89±10 cm s-1vs 123±5 cm s-1 (mean ± s.e.m.), respectively, N=6], a 19%lower AMR (147±12 μmol min-1 kg-1vs181±11 μmol min-1 kg-1, respectively), and a 30% lower maximum in vivo cardiac output (47.3±4.7 ml min-1 kg-1vs 68.0±5.2 ml min-1 kg-1, respectively). When cardiac performance was compared with an in situ heart preparation, hearts from poor swimmers had a significantly (26%) lower maximum cardiac output (45.9±1.9 ml min-1 kg-1vs 56.4±2.3 ml min-1 kg-1, respectively) and a 32% lower maximum cardiac power output at a high afterload (3.96±0.58 mW g-1vs 5.79±1.97 mW g-1, respectively). Cardiac morphology was visualised in vivo by Doppler echography on anaesthetised individual fish and revealed that poor swimmers had a significantly more rounded ventricle (reduced ventricle length to height ratio) compared with good swimmers, which in turn was correlated with fish condition factor. These results provide clear evidence that maximum cardiac performance is linked to AMR and Ucrit and indicate that a simple screening test can distinguish between rainbow trout with lower active metabolic rate, Ucrit, maximal cardiac pumping capacity and a more rounded ventricular morphology. These distinguishing traits may have been retained for 9 months despite a common growing environment and growth.
Quasistatic and continuous dynamic characterization of the mechanical properties of silk from the cobweb of the black widow spiderLatrodectus hesperus
Authors: Blackledge Todd A. , Swindeman John E. , Hayashi Cheryl Y.
Published: May 2005

Spider silks are among the strongest and toughest known materials, but investigation of these remarkable properties has been confined largely to orb-weaving spiders. We investigated the mechanical performance of silk from the cobweb-weaving spider Latrodectus hesperus. Both silk from the scaffolding region of the web and sticky gumfooted capture lines had material properties similar to the major ampullate silk that orb weavers use as the framework for their orb webs. Major ampullate fibers obtained from anaesthetized Latrodectus spiders were similar, but exhibited increased stiffness and reduced extensibility. Novel continuous dynamic analysis of the silks revealed that the loss tangent (tanδ) increased rapidly during the first 2-3% of extension and reached a maximum near the yield point of fibers. The loss tangent then rapidly declined at an ever-decreasing rate until failure. We suggest that these data support molecular models for the mechanics of spider silk. We also demonstrate that the addition of sticky aggregate glue to the ends of the gumfooted lines modulates their mechanical performance - reducing stiffness and increasing extensibility. The storage modulus of viscid regions of the gumfooted lines was much lower than dry regions. This may be explained by disruption of hydrogen bonding within the amorphous regions of the fibers due to hydration from the glue.
Nitric oxide modulates peristaltic muscle activity associated with fluid circulation in the sea pansyRenilla koellikeri
Authors: Anctil Michel , Poulain Isabelle , Pelletier Claudine
Published: May 2005

Nitric oxide (NO) is a well-known regulator of vascular activities in vertebrates and it has also been implicated as a vasodilatatory agent in a cephalopod. In the sea pansy Renilla koellikeri, an octocorallian representative of the most basal animals with a nervous system, we investigated the role of NO in peristalsis, an activity that moves body fluids through the coelenteron (gastrovascular cavity) of the polyps across the colony. NO donors increased the amplitude of peristaltic contractions and increased tonic contractions in relaxed preparations, but caused a relaxation of basal tension in contracted preparations. The NO synthase (NOS) inhibitors L-NAME (N(ω)-nitro-L-arginine methyl ester) and 7-nitroindazole reduced the amplitude of peristaltic contractions and lowered basal tension. In contrast, aminoguanidine, a specific inhibitor of inducible NOS, increased the amplitude but reduced the rate of peristalsis. Zaprinast, a cGMP-specific phosphodiesterase inhibitor, decreased the amplitude of peristaltic contractions, a decrease that was amplified by dibutyryl cGMP. In contrast,the inhibitor of soluble guanylyl cyclase ODQ(1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one) enhanced peristalsis. Putative NOS-containing neurons, revealed by NADPH-diaphorase activity and citrulline immunohistochemistry, were observed in the basiectoderm at the base of the autozooid polyp tentacles and in a nerve-net around the oral disc. Their neurites ran up the tentacles and down to the polyp body wall, crossing from the ectoderm through the mesoglea and into the endoderm musculature where musculo-epithelial cells were also reactive. These data suggest that two distinct nitrergic pathways, one of which is mediated by cGMP, regulate peristalsis and muscle tone in the sea pansy and that these pathways may involve NOS-containing ectodermal neurons and musculo-epithelial cells.
The ecology of visual pigment tuning in an Australian marsupial: the honey possumTarsipes rostratus
Authors: Sumner Petroc , Arrese Catherine A. , Partridge Julian C.
Published: May 2005

While most mammals have no more than two types of cone photoreceptor, four species of Australian marsupial have recently been shown to possess three types, and thus have the potential for trichromatic colour vision. Interestingly, the long-wave cones of the honey possum Tarsipes rostratus are tuned to longer wavelengths than those of the other species measured to date. We tested whether the honey possum's long-wave tuning is adaptive for visual tasks associated with its almost unique diet of nectar and pollen. We modelled three tasks: (1) detecting food-rich `target' flowers against their natural background of foliage or other vegetation; (2)discriminating target flowers from flowers of non-target species; (3)discerning the maturity of the most important target flowers. Initial comparisons of trichromacy vs dichromacy generally favoured the former, but interestingly dichromacy was no disadvantage in some cases. For tuning, we found that overall the honey possum's long-wave tuning is more adaptive than that of the other marsupial species. Nevertheless, the optimal tuning for tasks 1 and 2 would be at longer wavelengths still, implying that a different pressure or constraint operates against a further long-wave shift of the honey possum's L cone tuning. Our data show that a possible ecological pressure may be provided by the third task - the difficult and potentially critical discrimination of the maturity of the animal's major food supply, the flowers of Banksia attenuata.
Design of a combined cam-linkage mechanism with an oscillating roller follower by an analytical method
Authors: Ye Z , Smith M R
Published: May 2005

An analytical method for the design of the cam contour of a combined cam-linakge mechanism with an oscillating roller follower to trace precisely a predetermined locus is introduced. It is shown that the composition of the mechanism during kinematic analysis is profitably viewed differently from that during design. Furthermore, as the assembly mode of linkage mechanisms may change during design, a key feature of this paper is the explanation of how to deal with the change in assembly mode of Assur groups during design of such combined mechanisms.
Thermal analysis and optimization for a ball grid array package
Authors: Ho C-I , Hung T-C , Hung C-I
Published: May 2005

In this study, a computational fluid dynamics (CFD) approach is employed for heat transfer analysis of a ball grid array (BGA) package that is widely used in the modern electronics industry. Owing to the complicated geometric configuration of the BGA package, the submodel approach is used to investigate in detail the temperature distributions of thermal vias and solder balls. The effective thermal resistance of a BGA package has been successfully obtained from numerical simulations. An artificial neural network (ANN) is trained to establish the relationship between the geometry input and the thermal resistance output. The well-trained network is then coupled with the complex optimization method to search for the optimum design of the BGA package to achieve the lowest thermal resistance. The results of this study provide the electronic packaging industry with a reliable and rapid method for heat dissipation design of BGA packages.
Experimental study of the deformation behaviour of compacted metal powders used in a new rapid tooling process
Authors: Jiang Xiaoping , Liu Xingyang , Zhang Chao
Published: May 2005

To examine the feasibility of a newly proposed rapid tooling process based on the backing of a metal shell with metal powders, the compressive deformation behaviour of selected metal powders and metal shells was investigated. It was found that the mechanical properties of the powder material and the mixing ratio of powders of different sizes had a significant effect on the compressive deformation behaviour of the compacted powders. Softer metal powders with the same compressive stress tended to produce greater plastic deformation and formed a block under a stress of 138 MPa. Mixing two or more powders of different sizes could significantly increase the deformation resistance of the compacted powders. Minimum plastic deformation was achieved when the fraction of the coarse powder in a binary powder mixture reached 0.77. Initial loading at a higher stress could minimize or eliminate the plastic deformation in subsequent loading cycles. This feature could be used advantageously in powder packing for the proposed new rapid tooling process. Some elastic properties of the compacted metal powders were also determined from the compression experimental data.
An investigation on piezoelectric energy harvesting for MEMS power sources
Authors: Sohn J W , Choi S B , Lee D Y
Published: May 2005

This paper presents the feasibility of using piezoelectric materials in a power source for micro-electro-mechanical systems (MEMS) devices. The finite element method (FEM) is adopted to evaluate the power generations of commercially available piezofilms that are subjected to a fluctuating pressure source (blood pressure). The accuracy of the results obtained from the FEM is verified by comparing with the corresponding results obtained from a theoretical analysis. In addition, an experiment is undertaken in order to evaluate the power generation of two different shapes of the piezofilms: square and circle. Finally, a brief discussion is made on the storage of experimentally harvested power and use of the MEMS applications.
Real-world fuel economy and emission levels of a typical EURO-IV passenger vehicle
Authors: Samuel S , Morrey D , Fowkes M , Taylor D H C , Austin L , Felstead T , Latham S
Published: May 2005

This paper presents the findings of research into real-world emission levels of a typical EURO-IV passenger car in the United Kingdom (UK). Four real-world drive cycles representing typical urban driving in the UK were used for the experiments. The work identified that the real-world emission levels of a EURO-IV vehicle in the UK are significantly higher than the certified legislative emission levels. The present work also identified that tailpipe-out carbon monoxide is the most affected emission specie in a gasoline-powered vehicle for real-world driving conditions.
Experimental investigation of the effects of various factors on the emission characteristics of low-emission natural gas vehicles
Authors: Jang C , Lee J
Published: May 2005

The aim of this study was to investigate the effects of various factors on the emission characteristics of dedicated natural gas vehicles (NGVs). A conventional light-duty gasoline engine was modified to run on natural gas (NG) by a gas injection system. Experiments were mainly conducted on the optimization of an oxygen sensor, a catalytic converter, and an electronic control unit (ECU) control strategy affecting the emission characteristics of NGVs. Also presented are the emission results of the NGV as a low-emission vehicle by evaluating non-methane organic gases (NMOG). The experimental results present the optimization of the fuel control and exhaust system in NGV that is needed to meet the more stringent emission regulations. It is also suggested that non-methane hydrocarbons (NMHC) constitute about 95 per cent of NMOG, and light-end HCs (C2-C5) account for 91 per cent of total NMOG emissions.
Active roll control of an experimental articulated vehicle
Authors: Miège A J P , Cebon D
Published: May 2005

A new experimental articulated vehicle with computer-controlled suspensions is used to investigate the benefits of active roll control for heavy vehicles. The mechanical hardware, the instrumentation, and the distributed control architecture are detailed. A simple roll-plane model is developed and validated against experimental data, and used to design a controller based on lateral acceleration feedback. The controller is implemented and tested on the experimental vehicle. By tilting both the tractor drive axle and the trailer inwards, substantial reductions in normalized lateral load transfer are obtained, both in steady state and transient conditions. Power requirements are also considered.
Eco-friendly Synthesis of m-Tolunitrile by Heterogeneously Catalysed Liquid Phase Ammoxidation
Authors: Zhong Min , Liang Yong-guang , Liu Yuan , Ma Yu-long
Published: May 2005

The ammoxidation of m-xylene to m-tolunitrile over silica-supported Co–Mn–Ni catalyst was conducted for the first time in liquid phase without solvent in one-step procedure.
Highly Enantioselective Lipase-catalyzed Kinetic Resolution of 2-Silyloxy-1-propanol
Authors: Kawanami Yasuhiro , Itoh Kennji
Published: May 2005

The lipase-catalyzed kinetic resolutions of 2-benzyloxy- and 2-silyloxy-1-propanols have been investigated. Efficient modification of the substrate structure with the dimethylphenylsilyl protecting group and the use of lipase PS-D immobilized on diatomaceous earth were found to enhance the enantioselectivity and reactivity up to E = 240 at 0 °C.
In vivo excision of a single targeted nucleotide from an mRNA by a trans excision-splicing ribozyme
Authors: BAUM DANA A. , TESTA STEPHEN M.
Published: May 2005

We have previously reported the development of a group I intron-derived ribozyme that can bind an exogenous RNA substrate and excise from that substrate an internal segment in vitro, which allows for sequence-specific modification of RNA molecules. In this report, the activity of this trans excision-splicing ribozyme in a cellular environment, specifically Escherichia coli, was investigated. The ribozyme was re-engineered to target for excision a single-base insertion in the transcript of a green fluorescent protein, and fluorescence was exploited as a reporter for trans excision-splicing. We show that the ribozyme is able to catalyze the trans excision-splicing reaction in vivo and can repair the mutant transcripts. On average, 12% correction is observed as measured by fluorescence and at least 0.6% correction as confirmed through sequence analysis. This represents the first report of a biomolecule (in this case a ribozyme) that can selectively excise a targeted nucleotide from within an mRNA transcript in vivo. This new class of biochemical tools makes possible a wide variety of new experimental strategies, perhaps including a new approach to molecular-based therapeutics.
A functional relationship between helix 1 and the 900 tetraloop of 16S ribosomal RNA within the bacterial ribosome
Authors: BÉLANGER FRANÇOIS , THÉBERGE-JULIEN GABRIEL , CUNNINGHAM PHILIP R. , BRAKIER-GINGRAS LÉA
Published: May 2005

The conserved 900 tetraloop that caps helix 27 of 16S ribosomal RNA (rRNA) interacts with helix 24 of 16S rRNA and also with helix 67 of 23S rRNA, forming the intersubunit bridge B2c, proximal to the decoding center. In previous studies, we investigated how the interaction between the 900 tetraloop and helix 24 participates in subunit association and translational fidelity. In the present study, we investigated whether the 900 tetraloop is involved in other undetected interactions with different regions of the Escherichia coli 16S rRNA. Using a genetic complementation approach, we selected mutations in 16S rRNA that compensate for a 900 tetraloop mutation, A900G, which severely impairs subunit association and translational fidelity. Mutations were randomly introduced in 16S rRNA, using either a mutagenic XL1-Red E. coli strain or an error-prone PCR strategy. Gain-offunction mutations were selected in vivo with a specialized ribosome system. Two mutations, the deletion of U12 and the U12C substitution, were thus independently selected in helix 1 of 16S rRNA. This helix is located in the vicinity of helix 27, but does not directly contact the 900 tetraloop in the crystal structures of the ribosome. Both mutations correct the subunit association and translational fidelity defects caused by the A900G mutation, revealing an unanticipated functional interaction between these two regions of 16S rRNA.
Translational autocontrol of the Escherichia coli hfq RNA chaperone gene
Authors: VEČEREK BRANISLAV , MOLL ISABELLA , BLÄSI UDO
Published: May 2005

The conserved bacterial RNA chaperone Hfq has been shown to play an important role in post-transcriptional regulation. Here, we demonstrate that Hfq synthesis is autoregulated at the translational level. We have mapped two Hfq binding sites in the 5′-untranslated region of hfq mRNA and show that Hfq binding inhibits formation of the translation initiation complex. In vitro translation and in vivo studies further revealed that Hfq binding to both sites is required for efficient translational repression of hfq mRNA.