bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitrogen limitation of chemostat-grown Rhizobium etli elicits higher infection-thread formation in Phaseolus vulgaris
Authors: Brelles-Mariño Graciela , Boiardi José L.
Published: June 2009

The symbiotic association between rhizobia and legume roots is a complex process involving many steps. An infection thread is a tubular structure of host origin formed during the infection of legume roots by rhizobia. Previous studies with batch cultures have reported that optimal attachment of rhizobia to root hairs coincides with nutrient limitation. In this study, the ability of chemostat-grown, nutrient-limited Rhizobium etli cells to form infection threads with its symbiotic partner Phaseolus vulgaris was investigated. Rhizobia were grown in a chemostat in synthetic media under C- or N-limiting conditions. Infection-thread formation was examined after inoculation of seedlings with a rhizobial cell suspension from each treatment. The number of infection threads was estimated by light microscopy after staining root sections with o-toluidine. Exopolysaccharide (EPS) production was also measured, and the cellular content and electrophoretic pattern of lipopolysaccharide (LPS) determined semiquantitatively. N-limited cells showed a markedly higher infectivity (measured as infection-thread formation) than C-limited cells. With one of the two bean cultivars used, the number of infection threads produced by N-limited cells was higher than that produced by exponentially growing cells in batch cultures. The higher infectivity of N-limited cells was correlated with higher EPS production. Electrophoretic analysis of LPS showed that C- and N-limited cells shared a common profile but the relative concentration of short LPS forms differed.
Molecular characterization of the levansucrase gene from the endophytic sugarcane bacterium Acetobacter diazotrophicus SRT4
Authors: Arrieta Juan , Hernández Lázaro , Coego Alberto , Suárez Vivian , Balmori Ezequiel , Menéndez Carmen , Petit-Glatron Marie-Françoise , Chambert Régis , Selman-Housein Guillermo
Published: June 2009

The Acetobacter diazotrophicus SRT4 gene encoding levansucrase (EC 2.4.1.10) (IsdA) was isolated from a genomic library. The nucleotide sequence of a 2.3 kb DNA fragment sufficient for complementation of a levansucrase-deficient mutant (obtained by EMS treatment) was determined. The IsdA gene (1751 bp) coded for a polypeptide of molecular mass 64.9 kDa with an isoelectric point of 5.2. The N-terminal amino acid sequence of the extracellular levansucrase indicated the presence of a precursor protein with a putative signal sequence of 51 residues which is possibly cleaved in two successive steps. Expression of the IsdA gene from the lac promoter in Escherichia coli resulted in the production of a protein with levansucrase activity. The deduced amino acid sequence of the IsdA gene was 48% and 46% identical with the levansucrases from the Gram-negative bacteria Zymomonas mobilis and Erwinia amylovora, respectively, but only 28-31% identical with levansucrases from Gram-positive bacteria. Multiple alignments of published levansucrase sequences from Gram-negative and Gram-positive bacteria revealed eight conserved motifs. A comparison of the catalytic properties and the sequence of the A. diazotrophicus levansucrase with those of the Bacillus subtilis levansucrase suggested that one of these motifs may be involved in the specificity of the synthesized product. Disruption of the IsdA gene in the genome of A. diazotrophicus resulted in a mutant lacking both levansucrase activity and the ability to utilize sucrose as a carbon source, suggesting that levansucrase is the key enzyme in sucrose metabolism of A. diazotrophicus.
The frequency of chimeric molecules as a consequence of PCR co-amplification of 16S rRNA genes from different bacterial species
Authors: Wang Grace C. Y. , Wang Yue
Published: June 2009

Our understanding of microbial diversity is greatly hampered by the inability to culture as much as 99% of the microbial community in the biosphere. Development of methods for identification and determining microbial phylogenies based on gene sequences, and for recovering genes directly from diverse environmental samples has made it possible to study microbes without the need for cultivation. PCR techniques have revolutionized retrieval of conserved gene sequences. However, it is well known that co-amplification of homologous genes may generate chimeric sequences leading to descriptions of non-existent species. To quantify the frequency of chimeric sequences in PCR amplification of 16S rRNA genes, we chose several 16S rDNAs with known sequences and mixed them for PCR amplifications under various conditions. Using this model system, we detected 30% occurrence of chimeric sequences after 30 cycles of co-amplification of two nearly identical 16S rRNA genes. The frequency of chimera formation decreased to 12.9% and 14.7% for templates with 82% and 86% similarity, respectively. We also examined effects of the number of amplification cycles, length of elongation periods and presence of damaged DNA on chimera formation. The results should provide useful information for microbiologists who use PCR-based strategies to retrieve conserved genes from mixed genomes.
Disruption of a glycogen-branching enzyme gene, glgB, specifically affects the sporulation-associated phase of glycogen accumulation in Streptomyces aureofaciens
Authors: Homerová Dagmar , Benada Oldŗich , Kofroňová Olga , ŗežuchová Bronislava , Kormanec Jan
Published: June 2009

In the course of Streptomyces differentiation, glycogen is accumulated in two discrete phases: in substrate hyphae that undergo aerial mycelium formation (phase I), and during septation of aerial hyphae (phase II). We have disrupted a previously identified gene, glgB, encoding a putative glycogen-branching enzyme in Streptomyces aureofaciens. Disruption of the gene had no profound effect on sporulation. However, the amount of glycogen-like polysaccharides, compared to wild-type (WT) S. aureofaciens, decreased in the late stage of differentiation of the glgB-disrupted strain. Absorption spectra of polysaccharides extracted from the WT and glgB-disrupted strains have shown the presence of glycogen in both strains in the first stage of differentiation (aerial mycelium formation), and unbranched glucan was detected in the glgB-disrupted strain in the late stage of differentiation. The results were confirmed by electron microscopy after silver proteinate staining of glycogen granules. Two distinct glycogen-branching enzymes, which had temporally different expression during differentiation, were detected in WT S. aureofaciens. The absence of this enzyme activity in the late stage of differentiation in the glgB mutant suggests that the product of the glgB gene is responsible for phase II glycogen accumulation.
Efficient transformation of Lactobacillus sake by electroporation
Authors: Berthier Françoise , Zagorec Monique , Champomier-Vergès Marie , Ehrlich S. D. , Morel-Deville Françoise
Published: June 2009

A procedure to transform intact Lactobacillus sake cells by electroporation was developed through a systematic examination of the effect of changes in various parameters on the transformation efficiency of Lact. sake strain 64F. The most critical factors were found to be the electrical parameters, the composition of washing and electroporation/storage solutions, and the presence of MgCI2 in the expression medium. Under optimal conditions transformation efficiencies up to 107 transformants (μg supercoiled DNA)-1 were obtained. The optimized procedure was successfully applied to other Lact. sake strains and consistently yielded from 104 to 107 transformants (μg supercoiled DNA)-1.
Regulation of bacterial methane oxidation: transcription of the soluble methane mono-oxygenase operon of Methylococcus capsulatus (Bath) is repressed by copper ions
Authors: Nielsen Allan K. , Gerdes Kenn , Degn Hans , Colin Murrell J.
Published: June 2009

Methane is oxidized to methanol by the enzyme methane mono-oxygenase (MMO) in methanotrophic bacteria. In previous work, this multicomponent enzyme system has been extensively characterized at the biochemical and molecular level. Copper ions have been shown to irreversibly inhibit MMO activity in vivo and in vitro, but the effect of copper ions on transcription of the genes encoding the soluble (cytoplasmic) MMO (sMMO) has not previously been investigated. To examine more closely the regulation of bacterial methane oxidation and to determine the role of copper in this process, we have investigated transcriptional regulation of the sMMO gene cluster in the methanotrophic bacterium Methylococcus capsulatus (Bath). Using Northern blot analysis and primer extension experiments, it was shown that the six ORFs of the sMMO gene cluster are organized as an operon and the transcripts produced upon expression of this operon have been identified. The synthesis of these transcripts was under control of a single copper-regulated promoter, which is as yet not precisely defined.
Fur regulates the expression of iron-stress genes in the cyanobacterium Synechococcus sp. strain PCC 7942
Authors: Ghassemian Majid , Straus Neil A.
Published: June 2009

A homologue of the ‘ferric uptake regulation’ gene (fur) was isolated from the cyanobacterium Synechococcus sp. strain PCC 7942 by an Escherichia coli-based ‘in vivo repression assay’. The assay uses a reporter-gene construct containing the promoter region of the iron-regulated cyanobacterial gene isiA, fused to the coding region for chloramphenicol acetyltransferase. The isolated gene codes for a protein that has 41 % sequence similarity (36% identity) to Fur from E. coli and contains the putative iron-binding motif found in the Fur proteins of purple bacteria. No significant similarity was found to the DxtR repressor that regulates the expression of toxin and siderophore production in Gram-positive bacteria. Insertional mutagenesis of the cloned cyanobacterial fur gene led to the creation of heteroallelic mutants that showed iron-deficiency symptoms in iron-replete medium, including the constitutive production of flavodoxin and of hydroxamate siderophores. Failure to eliminate wild-type copies of the fur gene from the polyploid genome of Synechococcus 7942 implies that in this cyanobacterium Fur may have essential functions in addition to the regulation of genes involved in iron scavenging or photosynthetic electron transport.
Adaptive response of the archaeon Sulfolobus acidocaldarius BC65 to phosphate starvation
Authors: Osorio Gonzalo , Jerez Carlos A.
Published: June 2009

The adaptive response of the archaeon Sulfolobus acidocaldarius BC65 to phosphate starvation was studied. When cells were subjected to phosphate limitation, their growth was affected. In addition, the levels of synthesis and/or the degree of phosphorylation of several proteins changed, as detected by two-dimensional nonequilibrium pH gradient electrophoresis of cells labelled in vivo with [35S]methionine and [35S]cysteine, or H3
32PO4. After another growth-restricting treatment, a heat shock, a general inhibition of protein synthesis was observed. Under phosphate starvation conditions, a 36 kDa protein became phosphorylated without its synthesis being significantly modified, suggesting a probable regulatory role during adaptation of the cell to the change in the external environment. In Southern blot analysis with specific probes from very conserved regions of the phoR and phoB genes from Escherichia coli, a positive hybridization with S. acidocaldarius BC65 chromosomal DNA fragments was found. This suggested the presence in S. acidocaldarius BC65 of genes related to the E. coli genes involved in the phosphate starvation response system. This appears to be the first evidence of the possible existence of a two-component sensory system in a micro-organism from the archaeal kingdom Crenarchaeota.
Spread of injectate after ultrasound‐guided subcostal transversus abdominis plane block: a cadaveric study
Authors: Barrington M. J. , Ivanusic J. J. , Rozen W. M. , Hebbard P.
Published: June 2009

Ultrasound‐guided transversus abdominis plane (TAP) block can be performed using a subcostal technique. This technique was simulated using dye injection in cadavers in order to determine segmental nerve involvement and spread of injectate using either single or multiple‐injection techniques. Dye most commonly spread to affect T9 and T10 nerves with the single injection technique and T9, T10 and T11 with multiple injections. The median (IQR [range]) spread of dye was 60 (36–63 [32–78]) cm2 using the single‐injection technique and 90 (85–96 [72–136]) cm2, in the multiple‐injection technique, and this difference was statistically significant (p = 0.003). These results indicate that ultrasound‐guided subcostal TAP block will involve nerve roots T9, T10 and T11 and that a multiple‐injection technique may block more segmental nerves and increase spread of injectate.
Dental caries in cerebral palsied individuals and their caregivers' quality of life
Authors: Rodrigues dos Santos M. T. B. , Bianccardi M. , Celiberti P. , De Oliveira Guaré R.
Published: June 2009

Objective  To study the correlation between caries experience in individuals with cerebral palsy (CP) and the quality of life of their primary caregivers.

Materials and methods  Sixty‐five non‐institutionalized individuals, presenting CP, aged 2–21 years old, were evaluated for caries experience. Their respective caregivers aged 20–74 years old answered the Short Form 36 (SF‐36) health survey and Independence Measure for Children. Fifty‐eight non‐disabled individuals (ND group), aged 2–21 years old, and their respective caregivers, aged 25–56 years old, were submitted to the same evaluation process as the CP group.

Results  Primary caregivers of CP individuals exhibited significantly lower scores than the ND group in all subscales of the SF‐36 health survey questionnaire: physical functioning, physical role, bodily pain, general health, vitality, social functioning, emotional role and mental health. The CP group presented significantly higher values for the Decayed, Missed and Filled (DMF‐T) index than the ND group and a significant negative correlation was obtained between the SF‐36 and DMF‐T index.

Conclusion  The results suggest that caregivers of CP individuals exhibited worse quality of life than those of the non‐disabled. A negative correlation exists between caries experience of CP individuals and their caregivers' quality of life.
Stock, turnover time and accumulation of organic matter in bulk and density fractions of a Podzol soil
Authors: Schulze K. , Borken W. , Muhr J. , Matzner E.
Published: June 2009

Temperate forest soils store large amounts of organic matter and are considered as net sinks for atmospheric carbon dioxide. Information about the sink strength and the turnover time of soil organic carbon (SOC) is required to assess the potential response of soils to climate change. Here we report on stocks, turnover times (TT) and accumulation of SOC in bulk soil and density fractions from genetic horizons of a Podzol in the Fichtelgebirge, Germany. Stocks of SOC, total nitrogen and exchangeable cations determined in nine quantitative soil pits strongly varied with stone content and thickness of horizons in both the organic layer and the mineral soil. On the basis of radiocarbon signatures, mean turnover times of 4, 9 and 133 years, respectively, were calculated for Oi, Oe and Oa horizons from three soil pits, using a non‐steady‐state model. The Oa horizons accumulated 4–8 g C m−2 year−1 whereas the Oi and Oe horizons were close to steady‐state during the past decade. Free particulate organic matter (FPOM) was the most abundant fraction in the Oa and EA horizons with TT of 70–480 years. In the B horizons, mineral associated organic matter (MAOM) dominated with over 40% of total SOC and had TT of 390–2170 years. In contrast to other horizons, MAOM in the Bsh and Bs horizon had generally faster TT than occluded particulate organic matter (OPOM), possibly because of sorption of dissolved organic carbon by iron and aluminium oxides/hydroxides. Our results suggest that organic horizons with relatively short turnover times could be particularly vulnerable to changes in climate or other disturbances.
Disturbance and species displacement: different tolerances to stream drying and desiccation in a native and an invasive crayfish
Authors: LARSON ERIC R. , MAGOULICK DANIEL D. , TURNER CLINTON , LAYCOCK KELLY H.
Published: June 2009

1. Crayfish are among the most threatened taxa in the world and invasive crayfish are the primary cause of the decline of native crayfish. Most research has emphasised biotic interactions as the mechanism by which native crayfish are displaced by invasives, although crayfish occupy variable environments and the role of disturbance in facilitating crayfish invasion and displacement is understudied.

2. We compared tolerance to a disturbance, stream drying, in a native and invasive crayfish as a potential mechanism to explain their distribution. Our experiments and observations were conducted across scales, from laboratory environmental chambers to stream mesocosms to field sampling. We hypothesised that the invasive crayfish would be more tolerant of desiccation than the native, and that this physiological distinction between the two would be reflected in their distribution in relation to stream drying.

3. In the laboratory, the native crayfishOrconectes eupunctuswas less tolerant of desiccation than the invasiveOrconectes neglectus chaenodactylus, with all native crayfish dying within 2 days without water, while some of the invasive crayfish survived for nearly 2 weeks. Under simulated stream drying in mesocosms, only the nativeO. eupunctussurvived less well than in a control. Field sampling demonstrated a significant negative relationship betweenO. eupunctusdensity and low summer flows, whileO. neglectusdensity was positively associated with low summer flows. The greater resistance ofO. neglectusto drying could, through priority effects, inhibit recolonisation byO. eupunctusonce flow resumes.

4. Abiotic disturbances are potentially important to the displacement of native by invasive crayfish. Disturbance mediated displacement of aquatic species provides both an opportunity to conserve native species by maintaining or restoring habitat and disturbance regimes and is also a challenge due to increasing human water demand, flow regime alteration and global climate change.
Thrombopoietin controls proliferation of embryonic multipotent hematopoietic progenitors
Authors: Huang Xin , Sakamoto Hiroshi , Ogawa Minetaro
Published: June 2009

Thrombopoietin (TPO) stimulation was reported to increase the number of multipotent hematopoietic progenitor (MPP) colonies in a methylcellose colony assay using cells from mouse embryos. Here, we investigated the expression of Mpl, the TPO receptor, in the cells from the yolk sac (YS) and the embryo proper (EP). MPPs in c‐Kit+ population in the mouse embryo expressed Mpl. Using liquid cultures, we found that MPPs from YS and EP proliferated in the presence of TPO and stem cell factor (SCF), whereas their numbers were maintained by TPO alone. In contrast, proliferation induced by TPO and SCF was not observed in MPPs of the bone marrow. Interestingly, examination of MPPs from the fetal liver indicated that their proliferative activity was intermediate between that of early embryonic and adult MPPs. These data suggest that early embryonic MPPs switch to adult MPPs in the embryo. Furthermore, the proliferation of early embryonic MPPs was suppressed by AG490, a Janus kinase2 (JAK2) inhibitor; and TPO could be replaced by constitutively active signal transducer and activator of transcription 5 (STAT5) for the proliferation. Thus, JAK2 and STAT5 mediate at least a part of the proliferative signal in early embryonic MPPs.
Diabetic persons with foot ulcers and their perceptions of hyperbaric oxygen chamber therapy
Authors: Katarina Hjelm , Magnus Löndahl , Per Katzman , Jan Apelqvist
Published: June 2009

Aim.  To elucidate how diabetic patients with limb‐threatening foot lesions perceive and evaluate content and organisation of treatment in a multi‐place hyperbaric oxygen chamber.

Background.  To our knowledge there are no patients’ evaluations of diabetes care in a high‐technology area like the hyperbaric oxygen chamber. The burden on persons with diabetic foot complications might be increased if adjuvant therapy with hyperbaric oxygen therapy (HBOT) within a locked airtight vessel is given.

Design.  Explorative study.

Participants.  Participants were included in the HODFU study, a prospective randomised double‐blind study, designed to evaluate whether HBOT heals more chronic foot ulcers than placebo treatment with hyperbaric air. Six females and 13 males, aged 44–83 years (median 70), with diabetic foot ulcers, participated.

Method.  Focus‐group interviews by an external evaluator.

Results.  Management was perceived as well‐functioning with competent staff delivering quick treatment in a positive manner and in good co‐operation. HBOT sessions, in groups, were described as unproblematic and pleasant, through sharing experiences with others, although time‐consuming and tiring. Recognising the responsible physician and communication with other physicians in the health‐care chain was perceived as problematic. Placebo treatment, when given, did not reveal any problems; many perceived HBOT as the last resort and respondents had a negative view of future health and expressed fears of new wounds and amputation.

Conclusions and relevance to clinical practice.  From patients’ perspective HBOT in the delivered health‐care model was perceived as well‐functioning, taking into consideration both technical and relational aspects of care in this high‐technology environment. Communication with the patient and between different care givers, with a consistent message given and information about who is responsible and to whom one should turn, wherever treated, is the most crucial aspect of the model. Future fears need to be recognised and group interaction can be encouraged to share the burden of disease.
Should we preserve the inferior mesenteric artery during sigmoid colectomy?
Authors: Dobrowolski S. , Hać S. , Kobiela J. , śledziński Z.
Published: June 2009

Abstract  Ligation of the inferior mesenteric artery (IMA) during sigmoid colectomy may cause sympathetic denervation of the rectal stump. The purpose of our study was to investigate the functional results after sigmoid resection following ligation or preservation of the IMA. We prospectively analysed 44 patients (21 female and 23 male, mean age 60.6 ± 11.79 years) with sigmoid tumour. Sigmoid colectomy with preservation of the IMA was performed in 21 patients, and ligation of the IMA with sigmoidectomy was carried out in 23 patients. Bowel function follow‐up was performed by use of questionnaires: standardized functional questionnaire, constipation‐specific, and incontinence scales before, 6 and 12 months after surgery. The quality of life was measured by means of the Fecal Incontinence Quality of Life (FIQL) scale. After sigmoid colectomy with division of the IMA, patients presented with a higher rate of fecal incontinence and increased stool frequency compared with patients after sigmoid resection with preservation of the IMA. Deterioration of FIQL was also observed in patients with ligated IMA. Preservation of the IMA during sigmoid colectomy in selected patients lowers the frequency of postoperative impaired anorectal function.
Duration of symptom onset to hospital admission and admission to discharge or death in SARS in mainland China: a descriptive study
Authors: Feng Dan , Jia Na , Fang Li‐Qun , Richardus Jan Hendrik , Han Xiao‐Na , Cao Wu‐Chun , De Vlas Sake J.
Published: June 2009

Objective  To describe and analyse factors associated with the duration of disease onset to hospital admission, admission to discharge and admission to death for severe acute respiratory syndrome (SARS), using the recently developed comprehensive database covering all regions of mainland China, and compare the results within and outside China.

Methods  The database included all probable 5327 SARS cases, of whom 343 died. Linear regression (uni‐ and multivariate analysis) was performed for all three durations to test the impact of the following variables: sex, age, occupation, geographic location and period of the SARS epidemic (time since the first case, i.e. 16 November 2002).

Results  The average duration of onset of symptoms to hospital admission was 3.8 days, of admission to discharge for those who survived was 29.7 days, while admission to death for casualties was 17.4 days. Health care workers, patients from Tianjin and patients infected towards the end of the epidemic had the shortest duration of onset to admission. Regarding admission to discharge, particularly young patients and patients from Guangdong had the shortest duration. Older age was the sole factor associated with shorter duration of admission to death.

Conclusions  The average duration and pattern (with time of epidemic and age) of onset of symptoms to hospital admission of SARS patients in mainland China were comparable to other affected areas. The duration of hospital admission to discharge was shorter than elsewhere, possibly because of different hospitalisation policies. The duration of hospital admission to death in mainland China, however, appeared to be shorter than in other areas, which is in striking contrast to the much lower case fatality in mainland China.
The economic impact of SARS in Beijing, China
Authors: Beutels Philippe , Jia Na , Zhou Qing‐Yi , Smith Richard , Cao Wu‐Chun , De Vlas Sake J.
Published: June 2009

Objective  To document the impact of the severe acute respiratory syndrome (SARS) outbreak in Beijing on indicators of social and economic activity.

Methods  Associations between time series of daily and monthly SARS cases and deaths and volume of public train, airplane and cargo transport, tourism, household consumption patterns and gross domestic product growth in Beijing were investigated using the cross‐correlation function.

Results  Significant correlation coefficients were found for all indicators except wholesale accounts and expenditures on necessities, with the most significant correlations occurring with a delay of 1 day to 1 month.

Conclusions  Especially leisure activities, local and international transport and tourism were affected by SARS particularly in May 2003. Much of this consumption was merely postponed; but irrecoverable losses to the tourist sector alone were estimated at about US$ 1.4 bn, or 300 times the cost of treatment for SARS cases in Beijing.
Detection of Chalara fraxinea in common ash (Fraxinus excelsior) using real time PCR
Authors: Chandelier A. , André F. , Laurent F.
Published: June 2009

A real time PCR assay was developed for the detection of Chalara fraxinea in common ash. PCR primers and Taqman probes, based on the internal transcribed spacer region of the multi‐copy gene rDNA, were tested for specificity and sensitivity. The primers amplified an 81 bp fragment for C. fraxinea but did not amplify DNA from other Chalara species or from other fungi isolated from ash, whether pathogenic or saprophytic. The limit of detection was 5 pg of genomic DNA per PCR. Moreover, naturally‐infected samples were correctly diagnosed. A procedure for DNA extraction from woody tissues using an electric drill yielded DNA of an appropriate quality for real time PCR. This molecular method could be useful for routine analysis of this emergent pathogen and for epidemiological studies.
Efficiency of farmers' selection in a participatory barley breeding programme in Jordan
Authors: Fufa F. , Grando S. , Kafawin O. , Shakhatreh Y. , Ceccarelli S.
Published: June 2009

With 1 figure and 4 tables

The study assessed farmers’ and breeders’ selection efficiencies in one cycle of selection in a participatory barley breeding program. The selectors were compared with each other for objectively measured agronomic traits and for their selection scores. Farmers’ scores were positively correlated with grain yield in all locations while breeders’ scores not always. The selection criteria of farmers varied with location; those in low‐moisture areas selected for tall plants while those in high rainfall area for short. Breeders’ gave high scores to tall entries regardless of the selection environment. The results showed that in all locations farmers were at least as efficient as or, in most cases, more efficient than breeders in identifying high yielding genotypes with desirable traits for their specific environment indicating their competence in selection. Breeders appeared to select for their wide geographic mandate area while farmers focused on their specific locality. The finding indicates that decentralized participatory plant breeding is important to increase and stabilize productivity and maintain genetic diversity as each pocket area is occupied by the best and different genotypes.
Relationship between costs of lifestyle interventions and weight loss in overweight adults
Authors: Bogers R. P. , Barte J. C. M. , Schipper C. M. A. , Vijgen S. M. C. , De Hollander E. L. , Tariq L. , Milder I. E. J. , Bemelmans W. J. E.
Published: June 2009

Lifestyle interventions in a healthcare setting are effective for weight loss, but it is unclear whether more expensive interventions result in more weight loss. Our objective was to explore the relationship between intervention costs and effectiveness in a systematic review of randomized trials.

Intervention studies were selected from 14 reviews and from a systematic MEDLINE‐search. Studies had to contain a dietary and a physical activity component and report data on measured weight loss in healthy Caucasian overweight adults. Intervention costs were calculated in a standardized way. The association between costs and percentage weight loss after 1 year was assessed using regression analysis.

Nineteen original studies describing 31 interventions were selected. The relationship between weight loss and intervention costs was best described by an asymptotic regression model, which explained 47% of the variance in weight loss. A clinically relevant weight loss of 5% was already observed in interventions of approximately €110. Results were similar in an intention‐to‐treat analysis.

In conclusion, lifestyle interventions in health care for overweight adults are relatively cheap and higher intervention costs are associated with more weight loss, although the effect of costs on weight loss levels off with growing costs.
A Comparison of Adults with Intellectual Disabilities with and without ASD on Parallel Measures of Challenging Behaviour: The Behavior Problems Inventory‐01 (BPI‐01) and Autism Spectrum Disorders‐Behavior Problems for Intellectually Disabled Adults (ASD‐BPA)
Authors: Rojahn Johannes , Wilkins Jonathan , Matson Johnny L. , Boisjoli Jessica
Published: June 2009

Challenging behaviour may not be part of the diagnostic criteria for Autistic Disorder but they are frequently exhibited by children and adults with this condition. Levels of challenging behaviours are highest in individuals with an autism spectrum disorder (ASD) and co‐occurring intellectual disability (ID). The sample for this study consisted of 57 institutionalized adults with ID who either did or did not meet criteria for an ASD on a screening instrument [Autism Spectrum Disorders‐Diagnosis for Intellectually Disabled Adults (ASD‐DA)]. These two groups were compared on two parallel measures of challenging behaviour commonly used with this population: the Behavior Problems Inventory‐01 (BPI‐01) and Autism Spectrum Disorders‐Behavior Problems for Intellectually Disabled Adults (ASD‐BPA). Consistent with previous research, individuals with ASD demonstrated higher levels of overall challenging behaviour and especially with regard to self‐injurious and stereotypical behaviours. The convergent validity of these two scales was also demonstrated for the entire sample and by group.
Nested species subsets of amphibians and reptiles on Neotropical forest islands
Authors: Watling J. I. , Gerow K. , Donnelly M. A.
Published: June 2009

Nested species subsets are a common pattern of community assembly characteristic of many types of fragmented landscapes and insular systems. Here we describe nested subset patterns of amphibian and reptile occupancy on 23 forest islands in north‐eastern Bolivia. We used observed occupancy patterns to differentiate five distributional guilds: widespread species, rare species, poor colonizers, area‐sensitive species and supertramps. Amphibian occurrences were nested along a forest island isolation gradient, and when species from each of the distribution classes were removed from subsequent analyses of nestedness, we found that dispersal‐limited poor colonizers were responsible for the association between nestedness and isolation. Amphibians associated with the grassland matrix at the study site showed a nested pattern linked with area, although this pattern did not scale up to all amphibians and could not be unequivocally attributed to any of the distributional guilds we recognized. There were no strong associations between two biological characteristics, body size and relative abundance in the matrix, and the likelihood of occupancy along either forest island area or isolation gradients. The relative importance of isolation in shaping nested patterns of amphibians on these forest islands may be a result of either (1) the greater range in isolation values included in this study compared with many others; (2) the long time since isolation in this landscape, manifesting a footprint of isolation not apparent in more recently fragmented patches; (3) the relatively homogeneous grassland matrix surrounding forest islands that likely provides little refuge for animals moving among forest islands.
PACAP regulates immediate catecholamine release from adrenal chromaffin cells in an activity‐dependent manner through a protein kinase C‐dependent pathway
Authors: Kuri Barbara A. , Chan Shyue‐An , Smith Corey B.
Published: June 2009

Adrenal medullary chromaffin cells are a major peripheral output of the sympathetic nervous system. Catecholamine release from these cells is driven by synaptic excitation from the innervating splanchnic nerve. Acetylcholine has long been shown to be the primary transmitter at the splanchnic‐chromaffin synapse, acting through ionotropic nicotinic acetylcholine receptors to elicit action potential‐dependent secretion from the chromaffin cells. This cholinergic stimulation has been shown to desensitize under sustained stimulation, yet catecholamine release persists under this same condition. Recent evidence supports synaptic chromaffin cell stimulation through alternate transmitters. One candidate is pituitary adenylate cyclase activating peptide (PACAP), a peptide transmitter present in the adrenal medulla shown to have an excitatory effect on chromaffin cell secretion. In this study we utilize native neuronal stimulation of adrenal chromaffin cellsin situand amperometric catecholamine detection to demonstrate that PACAP specifically elicits catecholamine release under elevated splanchnic firing. Further data reveal that the immediate PACAP‐evoked stimulation involves a phospholipase C and protein kinase C‐dependant pathway to facilitate calcium influx through a Ni2+and mibefradil‐sensitive calcium conductance that results in catecholamine release. These data demonstrate that PACAP acts as a primary secretagogue at the sympatho‐adrenal synapse under the stress response.
To scale or not to scale: the principles of dose extrapolation
Authors: Sharma Vijay , McNeill John H
Published: June 2009

The principles of inter‐species dose extrapolation are poorly understood and applied. We provide an overview of the principles underlying dose scaling for size and dose adjustment for size‐independent differences. Scaling of a dose is required in three main situations: the anticipation of first‐in‐human doses for clinical trials, dose extrapolation in veterinary practice and dose extrapolation for experimental purposes. Each of these situations is discussed. Allometric scaling of drug doses is commonly used for practical reasons, but can be more accurate when one takes into account species differences in pharmacokinetic parameters (clearance, volume of distribution). Simple scaling of drug doses can be misleading for some drugs; correction for protein binding, physicochemical properties of the drug or species differences in physiological time can improve scaling. However, differences in drug transport and metabolism, and in the dose–response relationship, can override the effect of size alone. For this reason, a range of modelling approaches have been developed, which combinein silicosimulations with data obtainedin vitroand/orin vivo. Drugs that are unlikely to be amenable to simple allometric scaling of their clearance or dose include drugs that are highly protein‐bound, drugs that undergo extensive metabolism and active transport, drugs that undergo significant biliary excretion (MW > 500, ampiphilic, conjugated), drugs whose targets are subject to inter‐species differences in expression, affinity and distribution and drugs that undergo extensive renal secretion. In addition to inter‐species dose extrapolation, we provide an overview of dose extrapolation within species, discussing drug dosing in paediatrics and in the elderly.
Vitamin C: update on physiology and pharmacology
Authors: Mandl J , Szarka A , Bánhegyi G
Published: June 2009

Although ascorbic acid is an important water‐soluble antioxidant and enzyme cofactor in plants and animals, humans and some other species do not synthesize ascorbate due to the lack of the enzyme catalyzing the final step of the biosynthetic pathway, and for them it has become a vitamin. This review focuses on the role of ascorbate in various hydroxylation reactions and in the redox homeostasis of subcellular compartments including mitochondria and endoplasmic reticulum. Recently discovered functions of ascorbate in nucleic acid and histone dealkylation and proteoglycan deglycanation are also summarized. These new findings might delineate a role for ascorbate in the modulation of both pro‐ and anti‐carcinogenic mechanisms. Recent advances and perspectives in therapeutic applications are also reviewed. On the basis of new and earlier observations, the advantages of the lost ability to synthesize ascorbate are pondered. The increasing knowledge of the functions of ascorbate and of its molecular sites of action can mechanistically substantiate a place for ascorbate in the treatment of various diseases.
Treatment with the Kv7 potassium channel activator flupirtine is beneficial in two independent mouse models of pulmonary hypertension
Authors: Morecroft I , Murray A , Nilsen M , Gurney AM , MacLean MR
Published: June 2009

Background and purpose: Voltage‐gated potassium (Kv) channels contribute to resting membrane potential in pulmonary artery smooth muscle cells and are down regulated in patients with pulmonary arterial hypertension (PAH) and a contribution from Kv7 channels has been recently proposed. We investigated the effect of the Kv7 channel activator, flupirtine, on PAH in two independent mouse models: PAH induced by hypoxia and spontaneous PAH in mice over‐expressing the 5‐HT transporter (SERT+mice).

Experimental approach: Right ventricular pressure was assessedin vivoin mice chronically treated with flupirtine (30 mg·kg−1·day−1). In separatein vitroexperiments, pulmonary arteries from untreated mice were mounted in a wire myograph. Relaxations to acute administration of flupirtine and contractions to Kvchannel blocking drugs, including the Kv7 channel blocker linopirdine, were measured.

Key results: In wild‐type (WT) mice, hypoxia increased right ventricular pressure, pulmonary vascular remodelling and right ventricular hypertrophy. These effects were attenuated by flupirtine, which also attenuated these indices of PAH in SERT+mice. In thein vitroexperiments, flupirtine induced a potent relaxant response in arteries from untreated WT and SERT+mice. The relaxation was fully reversed by linopirdine, which potently contracted mouse pulmonary arteries while other Kvchannel blockers did not.

Conclusions and implications: Flupirtine significantly attenuated development of chronic hypoxia‐induced PAH in mice and reversed established PAH in SERT+mice, apparently via Kv7 channel activation. These results provide the first direct evidence that drugs activating Kv7 channels may be of benefit in the treatment of PAH with different aetiologies.
Oxidative stress may enhance the malignant potential of human hepatocellular carcinoma by telomerase activation
Authors: Nishikawa Taichiro , Nakajima Tomoki , Katagishi Tatsuo , Okada Yoshihisa , Jo Masayasu , Kagawa Keizo , Okanoue Takeshi , Itoh Yoshito , Yoshikawa Toshikazu
Published: June 2009

Background/Aims: Continuous oxidative stress (OS) plays an important role in the progression of chronic liver diseases and hepatocarcinogenesis through telomere shortening in hepatocytes. However, it has not been established how the OS influences the progression of human hepatocellular carcinomas (HCCs). We examined the correlations of OS with telomere length of cancer cells, telomerase activity and other clinicopathological factors in 68 HCCs.

Methods: The level of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) as a marker of OS was examined immunohistochemically and OS was scored in four grades (0–3). The telomere length of cancer cells was measured by quantitative fluorescence in situ hybridization. Telomerase activity was measured by (i) immunodetection of human telomerase reverse transcriptase (hTERT) and (ii) telomere repeat amplification protocol (TRAP) assay. Telomerase related proteins, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Akt, and other clinicopathological factors were also evaluated.

Results: As the OS grade increased, the average telomere length became significantly shorter in HCCs, especially in the hTERT‐negative group. In the state of high‐grade OS, hTERT‐positive HCC cells showed more proliferative and less apoptotic features compared with hTERT‐negative HCC cells. Telomerase activity, as measured by the TRAP assay, was strongly correlated with OS grade in HCCs. Furthermore, a high OS grade was correlated with the downexpression of PTEN and the activation of Akt.

Conclusions: Oxidative stress enhanced the malignant potential of HCCs through the activation of telomerase, which raises the possibility of using OS as a marker for assessing the clinical state of HCCs.
Paracorporeal Artificial Heart in Postoperative Heart Failure
Authors: Turina Marko T. , Bosio R. , Senning Åke
Published: June 2009

A pneumatically driven artificial heart with a tubular silicone rubber membrane and disc valves was used for functional heart replacement in the paracorporeal mode. A fluidic drive system allows adjustment of the heart rate, positive and negative pressures and systole/diastole ratio.

Since August, 1977, the artificial heart has been used in four patients with refractory postoperative heart failure not responding to volume loading, pH and electrolyte correction, catecholamines and intraaortic balloon pumping. Large cannulae were placed in the atria and great vessels. The ventricles were fixed on the chest paracorporeally. The assist system was used as a left heart bypass in one patient and as a biventricular bypass in three other patients. After 48–72 hours, the ventricular function recovered in three patients, permitting removal of the artificial heart. One patient died of cerebral complications six weeks later; the other two recovered completely and were released in good condition.

Profound postoperative heart failure can be completely reversed by the use of the paracorporeal artificial heart; the advantage of the system lies in the simplicity of its implantation and removal.
Preconditioning the diabetic human myocardium
Authors: Sivaraman Vivek , Hausenloy Derek J. , Wynne Abigail M. , Yellon Derek M.
Published: June 2009

Our objective was to determine whether human diabetic myocardium is amenable to the cardioprotective actions of ischaemic preconditioning. Human right atrial appendages were harvested from diabetic and non‐diabetic patients undergoing elective coronary artery bypass graft surgery. The atrial trabeculae were isolated and subjected to 90 min. of hypoxia followed by 120 min. of reoxygenation, following which the percentage recovery of baseline contractile function was determined. The atrial trabeculae were randomized to: (i) controls (groups 1 and 3); (ii) standard hypoxic preconditioning (HPC) protocol consisting of 4 min. of hypoxia/16 min. of reoxygenation before the 90 min. index hypoxic period (groups 2 and 4); (iii) Prolonged HPC protocol consisting of: 7 min. of hypoxia /16 min. of reoxygenation before the index hypoxic period (group 5). In addition, basal levels of Akt phosphorylation were determined in right atrial appendages harvested from non‐diabetic patients and diabetic patients to determine whether PI3K‐Akt signalling is down‐regulated in the diabetic heart. Standard HPC improved baseline contractile function in human atrial trabeculae harvested from non‐diabetic patients (52.4 ± 3.8% with HPC versus 30.0 ± 3.2% in control: P= 0.001; N= 6/group), but not in atrial trabeculae isolated from diabetic patients (22.6 ± 3.3% with HPC versus 28.5 ± 1.9% in control: P > 0.05; N= 6/group). However, the prolonged HPC protocol did improve baseline contractile function in atrial trabeculae harvested from diabetic patients (42.0 ± 2.4% with HPC versus 28.5 ± 1.9% in control: P= 0.001; N≥ 6/group). Western blot analysis demonstrated lower levels of phosphorylated Akt in diabetic myocardium compared to non‐diabetic myocardium (0.13 ± 0.03 arbitrary units versus 0.39 ± 0.11 arbitrary units: P= 0.047; N≥ 4/group). From the data obtained it appears that the threshold for preconditioning the diabetic myocardium is elevated which may be related to the down‐regulation of the PI3K‐Akt pathway.
Deficiency in TLR4 signal transduction ameliorates cardiac injury and cardiomyocyte contractile dysfunction during ischemia
Authors: Zhao Peng , Wang Jingying , He Leilei , Ma Heng , Zhang Xiaoyu , Zhu Xinglei , Dolence E. Kurt , Ren Jun , Li Ji
Published: June 2009

Toll‐like receptor 4 (TLR4), a proximal signalling receptor in innate immune responses to lipopolysaccharide of gram‐negative pathogens, is expressed in the heart. Accumulating evidence have consolidated the notion that TLR4 plays an essential role in the pathogenesis of cardiac dysfunction. However, the molecular mechanisms of TLR4 responsible for ischemia‐induced cardiac dysfunction remain unclear. To address the signalling mechanisms of TLR4‐deficiency cardioprotection against ischemic injury, in vivo regional ischemia was induced by occlusion of the left anterior descending coronary artery in wild‐type (WT) C3H/HeN and TLR4‐mutated C3H/HeJ mice. The results demonstrated that blunted ischemic activation of p38 mitogen‐activated protein kinase and JNK signalling occurred in C3H/HeJ hearts versus C3H/HeN hearts, while ERK and AMP‐activated protein kinase (AMPK) signalling pathways were augmented during ischemia in C3H/HeJ hearts versus C3H/HeN hearts. Intriguingly, ischemia‐stimulated endoplasmic reticulum stress was higher in C3H/HeN hearts than that in C3H/HeJ as demonstrated by up‐regulation of Grp78/BiP, Gadd153/CHOP and IRE‐1α. Myocardial infarct, caspase‐3 activity and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining demonstrated that C3H/HeN hearts suffered more damage than those of C3H/HeJ hearts during ischemia. Moreover, isolated cardiomyocytes from C3H/HeJ hearts showed resistance to hypoxia‐induced contractile dysfunction compared to those from C3H/HeN hearts, which are associated with greater hypoxic activation of AMPK and ERK signalling, better intracellular Ca2+ handling in C3H/HeJ versus C3H/HeN cardiomyocytes. These findings suggest that the cardioprotective effects against ischemic injury of hearts with deficiency in TLR4 signalling may be mediated through modulating AMPK and ERK signalling pathway during ischemia.