bluuebunny/crossref_metadata_2025 huggingface dataset:
What To Think If the Results of the National Institutes of Health Randomized Trial of Methicillin-ResistantStaphylococcus aureusand Vancomycin-ResistantEnterococcusControl Measures Are Negative (and Other Advice to Young Epidemiologists): A Review and an Au Revoir
Authors: Farr Barry M.
Published: September 2006

The incidence of methicillin-resistantStaphylococcus aureus(MRSA) and vancomycin-resistantEnterococcus(VRE) infections continues to rise in National Nosocomial Infections Surveillance system hospitals, and these pathogens are reportedly causing more than 100,000 infections and many deaths each year in US healthcare facilities. This has led some to insist that control measures are now urgently needed, but several recent articles have suggested that isolation of patients does not work, is not needed, or is unsafe, or that a single cluster-randomized trial could be used to decide such matters. At least 101 studies have reported controlling MRSA infection and 38 have reported controlling VRE infection by means of active detection by surveillance culture and use of isolation for all colonized patients in healthcare settings where the pathogens are epidemic or endemic, in academic and nonacademic hospitals, and in acute care, intensive care, and long-term care settings. MRSA colonization and infection have been controlled to exceedingly low levels in multiple nations and in the state of Western Australia for decades by use of active detection and isolation. Studies suggesting problems with using such data to control MRSA colonization and infection have their own problems, which are discussed. Randomized trials are epidemiologic tools that can sometimes provide erroneous results, and they have not been considered necessary for studying isolation before it is used to control other important infections, such as tuberculosis, smallpox, and severe acute respiratory syndrome. No single epidemiologic study should be considered definitive. One should always weigh all available evidence. Infection with antibiotic-resistant pathogens such as MRSA and VRE is controllable to a low level by active detection and isolation of colonized and infected patients. Effective measures should be used to minimize the morbidity and mortality attributable to these largely preventable infections.
A new, simple method for quantifying gemcitabine triphosphate in cancer cells using isocratic high‐performance liquid chromatography
Authors: Nishi Rie , Yamauchi Takahiro , Ueda Takanori
Published: September 2006

A deoxycytidine analog, gemcitabine (dFdC), is effective for treating solid tumors and hematological malignancies. After being transported into cancer cells, dFdC is phosphorylated to dFdC triphosphate (dFdCTP), which is subsequently incorporated into the DNA strand, thereby inhibiting DNA synthesis. Intracellular dFdCTP is the critical determinant for dFdC cytotoxicity, so therapeutic drug monitoring or in vitro testing of the capability of cancer cells to accumulate dFdCTP may be informative for optimizing dFdC administration. We have developed a new isocratic‐elution high‐performance liquid chromatography method for quantifying dFdCTP in cancer cells. Samples (500 µL) were eluted isocratically using 0.06 M Na2HPO4 (pH 6.9) containing 20% acetonitrile, at a constant flow rate of 0.7 mL/min and at ambient temperature. Separation was carried out using an anion‐exchange column (TSK gel DEAE‐2SW; 250 mm × 4.6 mm inside diameter, particle size 5 µL) and monitored at 254 nm. The standard curve was linear with low within‐day and interday variability. The lower detection limit (20 pmol) was as sensitive as that of the previous gradient‐elution method. dFdCTP was well separated from other nucleoside triphosphates. The method could measure dFdCTP in cultured or primary leukemic cells treated in vitro with dFdC. The method was also applicable to simultaneous determination of dFdCTP and cytarabine triphosphate, the results of which demonstrated ara‐CTP production augmented by dFdC pretreatment. Thus, our isocratic high‐performance liquid chromatography assay method will be of great use because of its sensitivity and simplicity as well as its applicability to biological materials. (Cancer Sci 2006; 97: 1274–1278)
Actin‐binding protein filamin A is displayed on the surface of human neuroblastoma cells
Authors: Bachmann André S. , Howard James P. , Vogel Carl‐Wilhelm
Published: September 2006

We previously reported the identification of natural human IgM antibodies, which recognize a Mr 260 000 surface protein (NB‐p260) and induce both complement‐mediated cytotoxicity and apoptosis of human neuroblastoma cells. NB‐p260 was shown to belong to the family of filamin proteins. Filamin A is a high molecular weight actin‐binding protein, previously thought to be only located intracellularly. Here we show that NB cells as well as three NB‐unrelated human cell lines express filamin A also on the cell surface. Our findings suggest new biological functions for filamins, including a role as mediators in anti‐NB IgM‐induced apoptosis, and they add to the growing body of evidence of the interaction of cytoskeletal proteins with the extracellular matrix. (Cancer Sci 2006; 97: 1359–1365)
Matriptase activates stromelysin (MMP‐3) and promotes tumor growth and angiogenesis
Authors: Jin Xinlian , Yagi Motoki , Akiyama Nagisa , Hirosaki Tomomi , Higashi Shouichi , Lin Chen‐Yong , Dickson Robert B. , Kitamura Hitoshi , Miyazaki Kaoru
Published: September 2006

Matriptase/MT‐SP1, a type II membrane serine protease widely expressed in normal epithelial cells and human carcinoma cells, is thought to be involved in cancer progression. To clarify this possibility, we overexpressed exogenous matriptase in the human stomach cancer cell line AZ521. In vitro, the matriptase transfectant (Mat‐AZ521) and the control transfectant (Mock‐AZ521) showed a similar growth rate, although the saturation cell density was significantly higher with the Mat‐AZ521. When implanted into nude mice subcutaneously or intraperitoneally, Mat‐AZ521 cells grew faster and produced much larger solid tumors than Mock‐AZ521 cells. The overexpression of matriptase in AZ521 cells shortened the survival time of tumor‐bearing mice. Histological analysis showed that both the number and the size of blood vessels in tumor tissues were significantly higher in the Mat‐AZ521 tumors than the Mock‐AZ521 ones. Moreover, it was found that purified matriptase activated one of the important matrix metalloproteinases, stromelysin (MMP‐3). These results suggest the possibility that the matriptase‐dependent activation of MMP‐3, as well as the direct activity of matriptase, promotes tumor growth and angiogenesis by enhancing extracellular matrix degradation in tumor cell microenvironments. (Cancer Sci 2006; 97: 1327–1334)
Antivascular effects of TZT‐1027 (Soblidotin) on murine Colon26 adenocarcinoma
Authors: Watanabe Junichi , Natsume Tsugitaka , Kobayashi Motohiro
Published: September 2006

We investigated the ability of TZT‐1027 (Soblidotin), a novel antimicrotubule agent, to induce antivascular effects, because most vascular targeting agents that selectively disrupt tumor vasculature also inhibit tubulin polymerization. Treatment with 10−7 g/mL TZT‐1027 rapidly disrupted the microtubule cytoskeleton in human umbilical vascular endothelial cells (HUVEC), and significantly enhanced vascular permeability in HUVEC monolayers. In addition, single intravenous administration of 2 mg/kg TZT‐1027 to mice bearing Colon26 tumors significantly reduced tumor perfusion and caused extravascular leakage of erythrocytes 1 h after administration. Subsequently, thrombus formation with deposition of fibrin and tumor necrosis was observed 3 and 24 h after administration, respectively. These results strongly suggest that TZT‐1027 possesses antivascular effects. TZT‐1027 induced apoptosis not only in HUVEC but also in C26 cancer cells (cell line of Colon26 solid tumor) in vitro, suggesting it exerts direct cytotoxicity against tumor cells in addition to its antivascular effects. A single intravenous administration of 1, 2 and 4 mg/kg TZT‐1027 significantly prolonged the survival of mice with advanced‐stage Colon26 tumors in a dose‐dependent manner. Furthermore, TZT‐1027 itself less markedly enhanced the permeability of normal vessels, but was additive with vascular endothelial growth factor, indicating the possibility that TZT‐1027 selectively exerts its activity on tumor vessels. In summary, these results suggest that TZT‐1027 exerts both an indirect antivascular effect and a direct cytotoxic effect, resulting in strong antitumor activity against advanced‐stage tumors, and that TZT‐1027 may be useful clinically for treating solid tumors. (Cancer Sci 2006; 97: 1410–1416)
Downregulation of circadian clock genes in chronic myeloid leukemia: Alternative methylation pattern of hPER3
Authors: Yang Ming‐Yu , Chang Jan‐Gowth , Lin Pai‐Mei , Tang Kai‐Ping , Chen Yen‐Hsu , Lin Hugo You‐Hsien , Liu Ta‐Chih , Hsiao Hui‐Hua , Liu Yi‐Chang , Lin Sheng‐Fung
Published: September 2006

Disruption of circadian rhythm is believed to play a critical role in cancer development. To gain further insights into the roles of circadian genes in chronic myeloid leukemia (CML), we analyzed peripheral blood from 53 healthy individuals and 35 CML patients for the expression of the nine circadian genes. The expression levels of hPER1, hPER2, hPER3, hCRY1, hCRY2 and hBMAL1 were significantly impaired in both chronic phase and blastic crisis of CML cases compared with those in healthy individuals (P < 0.001). Methylation studies in the promoter areas of these six genes revealed that only the CpG sites of the hPER3 gene were methylated in all of the CML patients, and the methylated CpG frequencies differed significantly in patients at blastic crisis (8.24 ± 0.73) or at chronic phase (4.48 ± 0.48). The CpG sites of the hPER2 gene were also methylated in 40% of the CML patients. No mutation was found within the coding region of hPER3 in CML cases. Our results suggest that the downregulated hPER3 expression in CML is correlated with the inactivation of hPER3 by methylation. (Cancer Sci 2006; 97: 1298–1307)
Progesterone receptor isoforms as a prognostic marker in human endometrial carcinoma
Authors: Saito Sumika , Ito Kiyoshi , Nagase Satoru , Suzuki Takashi , Akahira Jun‐Ichi , Okamura Kunihiro , Yaegashi Nobuo , Sasano Hironobu
Published: September 2006

The possible role of specific progesterone receptor (PR) isoforms (PRA and PRB) as predictive factors in endometrial carcinoma is unclear. The present study was undertaken to evaluate the clinical significance of intratumoral PR isoform status in patients with endometrioid endometrial carcinoma. We studied 103 cases of endometrioid endometrial carcinoma using immunohistochemistry. We correlated the findings with various clinicopathological parameters of the patients. PRA and PRB immunoreactivity was detected in 51/103 (48.5%) and 79/103 (76.7%) of carcinoma cases, respectively. A significant positive correlation was detected between the status of PRB immunoreactivity and the amount of PRB mRNA by real‐time reverse transcription–polymerase chain reaction (P = 0.012). PR isoform expression was significantly lower in the cases with higher histological grade (P = 0.0001 and P = 0.002, for PRA and PRB, respectively). Cases that were negative for either one or both PR isoforms were significantly associated with shorter disease‐free and overall survival of the patients. The absence of either one or both of these two PR isoforms was detected in all nine patients who died (100.0%), whereas the absence of these immunoreactivities was detected only in 43 of 94 (45.7%) patients who had lived during the same period. In addition, multivariate analysis demonstrated that an absence of PRA immunoreactivity was an independent risk factor in disease‐free survival of the patients (P = 0.0258). The results of our study demonstrated that loss or absence of PR isoform expression determined by immunohistochemistry could become an important prognostic indicator in patients with endometrioid endometrial carcinoma. (Cancer Sci 2006; 97: 1308–1314)
Lake depth rather than fish planktivory determines cladoceran community structure in Faroese lakes – evidence from contemporary data and sediments
Authors: AMSINCK SUSANNE LILDAL , STRZELCZAK AGNIESZKA , BJERRING RIKKE , LANDKILDEHUS FRANK , LAURIDSEN TORBEN L. , CHRISTOFFERSEN KIRSTEN , JEPPESEN ERIK
Published: September 2006

1. This study describes the environmental conditions and cladoceran community structure of 29 Faroese lakes with special focus on elucidating the impact of fish planktivory. In addition, long‐term changes in biological structure of the Faroese Lake Heygsvatn are investigated.

2. Present‐day species richness and community structure of cladocerans were identified from pelagial snapshot samples and from samples of surface sediment (0–1 cm). Multivariate statistical methods were applied to explore cladoceran species distribution relative to measured environmental variables. For Lake Heygsvatn, lake development was inferred by cladoceran‐based paleolimnological investigations of a14C‐dated sediment core covering the last ca 5700 years.

3. The 29 study lakes were overall shallow, small‐sized, oligotrophic and dominated by brown trout (Salmo trutta). Cladoceran species richness was overall higher in the surface sediment samples than in the snapshot samples.

4. Fish abundance was found to be of only minor importance in shaping cladoceran community and body size structure, presumably because of predominance of the less efficient zooplanktivore brown trout.

5. Canonical correspondence analysis showed maximum lake depth (Zmax) to be the only significant variable in explaining the sedimentary cladoceran species (18 cladoceran taxa, two pelagic, 16 benthic) distribution. Multivariate regression trees revealed benthic taxa to dominate in lakes withZmax < 4.8 m and pelagic taxa to dominate whenZmaxwas > 4.8 m.

6. Predictive models to inferZmaxwere developed using variance weighted‐averaging procedures. These were subsequently applied to subfossil cladoceran assemblages identified from a14C‐dated sediment core from Lake Heygsvatn and showed inferredZmaxto correspond well to the present‐day lake depth. A recent increase in inferredZmaxmay, however, be an artefact induced by, for instance, eutrophication.
Effects of a new antibacterial adhesive on the repair capacity of the pulp‐dentine complex in infected teeth
Authors: Tziafas D. , Koliniotou‐Koumpia E. , Tziafa C. , Papadimitriou S.
Published: September 2006

Aim  To evaluate the effects of a self‐etching/priming adhesive system, containing the antibacterial monomer 12‐methacryloyloxy‐dodecylpyridinium bromide (MDPB), on the repair capacity of the pulp‐dentine complex in infected cavities in dog's teeth.

Methodology  Class V cavities with a residual dentine thickness ranging from 0.3–0.8 mm were prepared on the buccal surface of permanent teeth in four dogs. Pulpal exposures were performed in half of the cavities. Millipore filters that had been incubated for 3 h in a 105 milky suspension of a‐streptococci were placed in the cavities, which were then filled temporarily. After 24 h, the filters were removed and both the exposed and non‐exposed cavities were washed with sterile saline and assigned to four groups which were treated with either the experimental antibacterial adhesive system, or Clearfil SE bond, Dycal and Teflon discs. Stereotype connective tissue reactions (inflammatory cell response and/or tissue necrosis) and pulp‐specific reparative tissue responses (reduction of odontoblasts and tertiary dentine formation) were assessed at post‐operative periods of 4 and 8 weeks.

Results  Neither severe inflammation nor tissue necrosis was observed, either in the dentinal cavities or pulpal exposures treated with the self‐etch adhesive containing MDPB. Rates of tertiary dentine formation in infected dentinal cavities treated with this system were comparable with those observed after dentine treatment with the Ca(OH)2‐based material. Dentinal bridging was not seen in pulpal exposures treated with the experimental adhesive.

Conclusions  The new antibacterial adhesive system maintained pulp vitality and primary odontoblastic function in infected nonexposed and exposed cavities but interfered with reparative dentine formation in infected pulpal exposures.
Interactions between non‐native plant species and the floristic composition of common habitats
Authors: MASKELL L. C. , FIRBANK L. G. , THOMPSON K. , BULLOCK J. M. , SMART S. M.
Published: September 2006

We investigated the role of non‐native species (neophytes) in common British plant communities using botanical data from two stratified random surveys carried out in 1990 and 1998.

We found that from 16 851 plots surveyed in 1998 there were 123 non‐native species found mostly in arable, tall grass/herb and fertile grassland habitats. Invasive non‐native species, e.g. Fallopia japonica, Impatiens glandulifera and Rhododendron ponticum, were uncommon in this survey.

Between 1990 and 1998 the total number of non‐native species increased but the mean number of species per sample plot decreased. The mean cover of non‐natives increased from 1.2% to 1.9%.

There were positive spatial and temporal relationships between non‐native and native species diversity. However, there was a weak negative relationship between changes in non‐native cover and native diversity.

The species composition and ecological traits of communities containing non‐natives were very different from those that did not contain them.

In the British countryside non‐native species were mainly found in habitats with anthropogenic associations, high fertility, high number of ruderal species and high diversity. There is also an indication that successional shifts where competitive invasive species dominate involve non‐native species.

National‐scale changes in plant community composition are likely to be closely correlated with external land‐use impacts. Changes such as eutrophication, nitrogen deposition and increased fertility in infertile habitats are likely to benefit both native and non‐native invasive species; however, currently these trends benefit native species much more often than non‐natives.

Non‐native species are known to have significant effects on native species at local scales in many countries; however, at the landscape scale in Great Britain they are best considered as symptoms of disturbance and land‐use change rather than a direct threat to biodiversity.
Do social information‐processing models explain aggressive behaviour by children with mild intellectual disabilities in residential care?
Authors: Van Nieuwenhuijzen M. , De Castro B. O. , Van Der Valk I. , Wijnroks L. , Vermeer A. , Matthys W.
Published: September 2006

Background  This study aimed to examine whether the social information‐processing model (SIP model) applies to aggressive behaviour by children with mild intellectual disabilities (MID). The response‐decision element of SIP was expected to be unnecessary to explain aggressive behaviour in these children, and SIP was expected to mediate the relation between social schemata and aggressive behaviour.

Method  SIP and aggressive behaviour of 130 10‐ to 14‐year‐old children with MID in residential care were assessed. The fit of various SIP models was tested with structural equation modelling.

Results  The response‐decision process was found not to be necessary to explain aggressive behaviour. Social schemata were indirectly related to aggressive behaviour with aggressive response generation as mediating variable.

Conclusions  Implications for SIP theory and intervention are discussed.
A review of the reliability and validity of Likert‐type scales for people with intellectual disability
Authors: Hartley S. L. , MacLean W. E.
Published: September 2006

Background  Likert‐type scales are increasingly being used among people with intellectual disability (ID). These scales offer an efficient method for capturing a wide range of variance in self‐reported attitudes and behaviours. This review is an attempt to evaluate the reliability and validity of Likert‐type scales in people with ID.

Methods  Fifty‐one studies reporting response rates, response bias, reliability and validity of Likert‐type scales among adolescents and adults with ID were reviewed.

Results  Low response rates were found among adolescents and adults with moderate to profound ID, when pictorial representations of response alternatives were not employed, and for Likert‐type scales with self‐descriptive statements. Response bias was evident, particularly among adolescents and adults with moderate to profound ID. Likert‐type scales have better reliability and validity among adolescents and adults with borderline IQ or mild ID. Pretests and clarifying questions increase reliability and validity.

Conclusions  Likert‐type scales should include pictorial representations of response alternatives, a single set of one or two word response descriptors, clarifying questions, and pretests, and are best used with adolescents and adults with borderline IQ to mild ID.
Right bundle branch block and long‐term mortality in patients with acute congestive heart failure
Authors: MUELLER C. , LAULE‐KILIAN K. , KLIMA T. , BREIDTHARDT T. , HOCHHOLZER W. , PERRUCHOUD A. P. , CHRIST M.
Published: September 2006

Objectives.  Risk stratification in acute congestive heart failure (ACHF) is poorly defined. The aim of the present study was to assess the impact of right bundle brunch block (RBBB) on long‐term mortality in patients presenting with ACHF.

Methods and results.  The initial 12‐lead electrocardiogram was analysed for RBBB in 192 consecutive patients presenting with ACHF to the emergency department. The primary endpoint was all‐cause mortality during 720‐day follow‐up. This study included an elderly cohort (mean age 74 years) of ACHF patients. RBBB was present in 27 patients (14%). Age, sex, B‐type natriuretic peptide levels and initial management were similar in patients with RBBB when compared with patients without RBBB. However, patients with RBBB more often had pulmonary comorbidity. A total of 84 patients died during follow‐up. Kaplan–Meier analysis revealed that mortality at 720 days was significantly higher in patients with RBBB when compared with patients without RBBB (63% vs. 39%, P = 0.004). In Cox proportional hazard analysis, RBBB was associated with a two‐fold increase in mortality (hazard ratio 2.18, 95% CI 1.26–3.66; P = 0.003). This association persisted after adjustment for age and comorbidity.

Conclusions.  RBBB is a powerful predictor of mortality in patients with ACHF. Early identification of this high‐risk group may help to offer tailored treatment in order to improve outcome.
Antipsychotics and risk of first‐time hospitalization for myocardial infarction: a population‐based case–control study
Authors: NAKAGAWA S. , PEDERSEN L. , OLSEN M. L. , MORTENSEN P. B. , SØRENSEN H. T. , JOHNSEN S. P.
Published: September 2006

Background.  Use of antipsychotics has been linked with an adverse cardiovascular risk factor profile and an increased risk of dysrhythmia and sudden cardiac death. However, detailed data on the association between use of antipsychotics and development of atherosclerotic disease are limited.

Objective.  To examine risk of hospitalization for myocardial infarction (MI) amongst users of antipsychotics compared with non‐users.

Design and subjects.  A population‐based case–control study using data from hospital discharge registries in the counties of North Jutland, Viborg and Aarhus, Denmark, and the Danish Civil Registration System. We identified 21 377 cases of first‐time hospitalization for MI and 106 885 sex‐ and age‐matched non‐MI population controls in the period 1992–2004. All prescriptions for antipsychotics filled prior to the date of admission for MI were retrieved from population‐based prescription databases. We used conditional logistic regression to adjust for a wide range of covariates.

Results.  Current users of atypical [adjusted relative risk: 0.98, 95% confidence interval (CI): 0.88–1.09] and typical antipsychotics (adjusted relative risk: 0.99, 95% CI: 0.96–1.03) had no increased overall risk of being admitted to hospital for MI when compared with non‐users of antipsychotics. These findings were consistent in all examined subgroups. Further, we found no association between the cumulative dose of antipsychotics and the risk of hospitalization for MI.

Conclusion.  These findings do not support the hypothesis that use of antipsychotics and in particular atypical antipsychotics is associated with increased risk of MI.
A simple diagnostic strategy in hospitalized patients with clinically suspected pulmonary embolism
Authors: KRUIP M. J. H. A. , SÖHNE M. , NIJKEUTER M. , KWAKKEL‐VAN ERP H. M. , TICK L. W. , HALKES S. J. M. , PRINS M. H. , KRAMER M. H. H. , HUISMAN M. V. , BÜLLER H. R. , LEEBEEK F. W. G. ,   on behalf of the Christopher Study Investigators
Published: September 2006

Objectives.  Diagnostic strategies in patients with suspected pulmonary embolism have been extensively studied in outpatients; their value in hospitalized patients has not been well established. Our aim was to determine the safety and clinical utility of a simple diagnostic strategy in hospitalized patients with suspected pulmonary embolism.

Design.  Prospective management study.

Setting.  Twelve teaching hospitals (five academic, seven general hospitals).

Subject.  A total of 605 hospitalized patients with clinically suspected pulmonary embolism. All patients completed the study.

Interventions.  First the clinical decision rule (CDR)‐score was calculated. An unlikely CDR‐score in combination with a normal D‐dimer excluded pulmonary embolism. All other patients underwent helical computed tomography (CT). CT either diagnosed or excluded pulmonary embolism, in which case anticoagulants were started or withheld. All patients were instructed to report symptoms of venous thrombosis. Objective tests were performed to confirm venous thromboembolism. The primary outcome was the incidence of symptomatic venous thrombosis during 3‐month follow‐up.

Results.  The combination of an unlikely CDR‐score and a normal D‐dimer excluded pulmonary embolism in 60 patients (10% of all patients); no venous thromboembolic event occurred during follow‐up (0%; 95% CI 0–6.7%). CT excluded pulmonary embolism in 380 patients; during follow‐up venous thromboembolism occurred in five patients (1.4%; 95% CI 0.4–3.1%).

Conclusions.  An unlikely CDR‐score in combination with a normal D‐dimer appears to exclude pulmonary embolism safely in hospitalized patients. Before clinical implementation it is important this safety is confirmed by others. CT testing was obviated in only 10% of patients. CT can safely exclude pulmonary embolism in hospitalized patients.
Population structure within and between subspecies of the Mediterranean triplefin fish Tripterygion delaisi revealed by highly polymorphic microsatellite loci
Authors: CARRERAS‐CARBONELL J. , MACPHERSON E. , PASCUAL M.
Published: September 2006

Although FST values are widely used to elucidate population relationships, in some cases, when employing highly polymorphic loci, they should be regarded with caution, particularly when subspecies are under consideration. Tripterygion delaisi presents two subspecies that were investigated here, using 10 microsatellite loci. A Bayesian approach allowed us to clearly identify both subspecies as two different evolutionary significant units. However, low FST values were found between subspecies as a consequence of the large number of alleles per locus, while homoplasy could be disregarded as indicated by the standardized genetic distance . Heterozygosity saturation was observed in highly polymorphic loci containing more than 15 alleles, and this threshold was used to define two loci pools. The less variable loci pool revealed higher genetic variance between subspecies, while the more variable pool showed higher genetic variance between populations. Furthermore, higher differentiation was also observed between populations using with the more variable loci. Nonetheless, a more reliable population structure within subspecies was obtained when all loci were included in the analyses. In T. d. xanthosoma, isolation by distance was detected between the eight analysed populations, and six genetically homogeneous clusters were inferred by Bayesian analyses that are in accordance with FST values. The neighbourhood‐size method also indicated rather small dispersal capabilities. In conclusion, in fish with limited adult and larval dispersal capabilities, continuous rocky habitat seems to allow contact between populations and prevent genetic differentiation, while large discontinuities of sand or deep‐water channels seems to reduce gene flow.
Absence of population structure of turbot (Psetta maxima) in the Baltic Sea
Authors: FLORIN ANN‐BRITT , HÖGLUND JACOB
Published: September 2006

We found low, albeit significant, genetic differentiation among turbot (Psetta maxima) in the Baltic Sea but in contrast to earlier findings we found no evidence of isolation by distance. In fact temporal variation among years in one locality exceeded spatial variation among localities. This is an unexpected result since adult turbot are sedentary and eggs are demersal at the salinities occurring in the Baltic. Our findings are most likely explained by the fact that we sampled fish that were born after/during a large influx of water to the Baltic Sea, which may have had the consequence that previously locally and relatively sedentary populations became admixed. These results suggest that populations that colonize relatively variable habitats, like the Baltic, face problems. Any adaptations to local conditions that may build up during stable periods may quickly become eroded when conditions change and/or when populations become admixed. Our results indicate that the ability of turbot to survive and reproduce at the low salinity in the Baltic is more likely due to phenotypic plasticity than a strict genetic adaptation to low salinity.
Dual function of the germinal centre kinase Don3 during mitosis and cytokinesis in Ustilago maydis
Authors: Sandrock Björn , Böhmer Christian , Bölker Michael
Published: September 2006

Septum formation is a crucial step of cytokinesis in fungi. In the basidiomycete Ustilago maydis, the germinal centre kinase Don3 triggers initiation of a secondary septum necessary for cell separation after cytokinesis. Here we show that oligomerization of Don3 via a putative coiled‐coil domain is critical for secondary septum formation. Within the Don3 sequence we detected a characteristic C‐terminal sequence motif (T‐motif), which determines the subcellular localization of Don3 but is not required for regulation of cell separation. This motif defines a novel family of fungal protein kinases including Sid1p, an essential component of the septation initiation network (SIN) in Schizosaccharomyces pombe. Using the yeast two‐hybrid system we isolated the Don3‐interacting protein Dip1, which is similar to S. pombe Cdc14p, another member of the SIN. Remarkably, deletion of dip1 did not interfere with cytokinesis in U. maydis, but both dip1 and don3 mutants were affected in nuclear envelope breakdown (NEBD) during mitosis. This phenotype has already been described for mutants, which lack the small GTPase Ras3, the U. maydis homologue of the SIN component Spg1p. We propose that the Don3 kinase exerts a dual function in the regulation of cell separation and NEBD.
The Group B Streptococcus NADH oxidase Nox‐2 is involved in fatty acid biosynthesis during aerobic growth and contributes to virulence
Authors: Yamamoto Yuji , Pargade Vincent , Lamberet Gilles , Gaudu Philippe , Thomas Fabrice , Texereau Joelle , Gruss Alexandra , Trieu‐Cuot Patrick , Poyart Claire
Published: September 2006

Numerous Streptococcaceae produce an H2O‐forming NADH oxidase, Nox‐2, which has been generally implicated in aerobic survival. We examined the roles of Nox‐2 in Group B Streptococcus (GBS), a leading agent of neonatal infections. While nox2 inactivation caused an aerobic growth arrest, no improvement was seen by addition of antioxidants to cultures, suggesting that this defect was not due to accumulation of toxic oxygen species. Using several approaches, we show that the observed inability of the nox2 mutant to grow aerobically is mainly due to an underlying defect in fatty acid (FA) biosynthesis: (i) the nox2 aerobic growth defect is fully and rapidly complemented by adding oleic acid to culture medium, and (ii) direct assimilation of this unsaturated FA in both wild type (WT) and nox2 GBS membranes is demonstrated and correlated with mutant growth rescue. We propose that NAD+ depletion in the nox2 mutant results in reduced acetyl‐CoA production, which perturbs FA biosynthesis and hence blocks growth in aerobiosis. The nox2 aerobic growth defect was also complemented when GBS respiration metabolism was activated by exogenous haem and menaquinone. The membrane NADH oxidase activity generated by the functional respiratory chain thus compensates the cytoplasmic NADH oxidase deficiency. The nox2 mutant was attenuated for virulence, as assessed in lung, intraperitoneal and intravenous murine infection models. As the nox2 defect seems only to affect aerobic growth of GBS, its reduced virulence supports the suggestion that aerobic conditions and NADH oxidase activities are relevant to the GBS infection process.
Type IV pili‐dependent gliding motility in the Gram‐positive pathogen Clostridium perfringens and other Clostridia
Authors: Varga John J. , Nguyen Van , O'Brien David K. , Rodgers Katherine , Walker Richard A. , Melville Stephen B.
Published: September 2006

Bacteria can swim in liquid media by flagellar rotation and can move on surfaces via gliding or twitching motility. One type of gliding motility involves the extension, attachment and retraction of type IV pili (TFP), which pull the bacterium towards the site of attachment. TFP‐dependent gliding motility has been seen in many Gram‐negative bacteria but not in Gram‐positive bacteria. Recently, the genome sequences of three strains of Clostridium perfringens have been completed and we identified gene products involved in producing TFP in each strain. Here we show that C. perfringens produces TFP and moves with an unusual form of gliding motility involving groups of densely packed cells moving away from the edge of a colony in curvilinear flares. Mutations introduced into the pilT and pilC genes of C. perfringens abolished motility and surface localization of TFP. Genes encoding TFP are also found in the genomes of all nine Clostridium species sequenced thus far and we demonstrated that Clostridium beijerinckii can move via gliding motility. It has recently been proposed that the Clostridia are the oldest Eubacterial class and the ubiquity of TFP in this class suggests that a Clostridia‐like ancestor possessed TFP, which evolved into the forms seen in many Gram‐negative species.
Roles for DNA supercoiling and the Fis protein in modulating expression of virulence genes during intracellular growth of Salmonella enterica serovar Typhimurium
Authors: Ó Cróinín Tadhg , Carroll Ronan K. , Kelly Arlene , Dorman Charles J.
Published: September 2006

Adaptation of bacterial pathogens to an intracellular environment requires resetting of the expression levels of a wide range of both virulence and housekeeping genes. We investigated the possibility that changes in DNA supercoiling could modulate the expression of genes known to be important in the intracellular growth of the pathogen Salmonella enterica serovar Typhimurium. Our data show that DNA becomes relaxed when Salmonella grows in murine macrophage but not in epithelial cells, indicating that DNA supercoiling plays a role in discrimination between two types of intracellular environment. The ssrA regulatory gene within the SPI‐2 pathogenicity island that is required for survival in macrophage was found to be upregulated by DNA relaxation. This enhancement of expression also required the Fis nucleoid‐associated protein. Manipulating the level of the Fis protein modulated both the level of DNA supercoiling and ssrA transcription. We discuss a model of bacterial intracellular adaptation in which Fis and DNA supercoiling collaborate to fine‐tune virulence gene expression.
Pre‐replication assembly of E. coli replisome components
Authors: Den Blaauwen Tanneke , Aarsman Mirjam E. G. , Wheeler Linda J. , Nanninga Nanne
Published: September 2006

The localization of SeqA, thymidylate synthase, DnaB (helicase) and the DNA polymerase components α and τ, has been studied by immunofluorescence microscopy. The origin has been labelled through GFP‐LacI bound near oriC. SeqA was located in the cell centre for one replication factory (RF) and at 1/4 and 3/4 positions in pre‐divisional cells harbouring two RFs. The transition of central to 1/4 and 3/4 positions of SeqA appeared abrupt. Labelled thymidylate synthetase was found all over the cell, thus not supporting the notion of a dNTP‐synthesizing complex exclusively localized near the RF. More DnaB, α and τ foci were found than expected. We have hypothesized that extra foci arise at pre‐replication assembly sites, where the number of sites equals the number of origins, i.e. the number of future RFs. A reasonable agreement was found between predicted and found foci. In the case of multifork replication the number of foci appeared consistent with the assumption that three RFs are grouped into a higher‐order structure. The RF is probably separate from the foci containing SeqA and the hemi‐methylated SeqA binding sites because these foci did not coincide significantly with DnaB as marker of the RF. Co‐labelling of DnaB and oriC revealed limited colocalization, indicating that DnaB did not yet become associated with oriC at a pre‐replication assembly site. DnaB and τ co‐labelled in the cell centre, though not at presumed pre‐replication assembly sites. By contrast, α and τ co‐labelled consistently suggesting that they are already associated before replication starts.
Unexpected twist: harnessing the energy in positive supercoils to control telomere resolution
Authors: Bankhead Troy , Kobryn Kerri , Chaconas George
Published: September 2006

Negative DNA supercoiling is an important conformational property of bacterial DNA that plays a significant role in a wide variety of DNA transactions. In contrast, positive DNA supercoiling is a by‐product of cellular processes that involve helical unwinding or movement of DNA by a fixed translocase, and has generally been considered a necessary evil requiring removal. We now report the first evidence suggesting a physiological role for positive supercoiling; this occurs in telomere resolution in the related Lyme disease and relapsing fever Borrelia spirochetes. Telomere resolution is the process whereby covalently closed hairpin telomeres are generated from replicative intermediates by the telomere resolvase, ResT. We observe a 20‐fold and greater stimulation of the reaction by positive supercoiling, which facilitates formation of a previously unobserved reaction intermediate. Our data suggest the possibility that the free energy of positive supercoiling, a resource with no previously described cellular function, may be harnessed and utilized as a regulator of post‐replication events.
Polymerase chain reaction in comparison with serological tests for early diagnosis of human leptospirosis
Authors: De Abreu Fonseca Claudia , Teixeira de Freitas Vera Lúcia , Caló Romero Eliete , Spinosa Claudia , Arroyo Sanches Maria Carmem , Da Silva Marcos Vinícius , Shikanai‐Yasuda Maria Aparecida
Published: September 2006

The aim of this study was to compare the sensitivity and specificity of polymerase chain reaction (PCR) using two primer pairs and combined with blood culture, immunoglobulin M enzyme‐linked immunosorbent assay (IgM ELISA), microscopic agglutination test (MAT) and slide agglutination test (SAT) in the diagnosis of human leptospirosis. We analysed 124 serum samples: 60 from patients with confirmed leptospirosis, 20 from patients with other diseases and 44 from healthy individuals. Analysing the first serum sample collected during the first 3–8 days of disease, the sensitivities of the four tests MAT, IgM ELISA, SAT and PCR were, respectively, 69.0%, 79.3%, 72.4% and 62%. In subsequent samples, those same sensitivities were, respectively, 95.4%, 100%, 100% and 72.7% in samples collected from days 9 to 14 and 88.9%, 88.9%, 77.8% and 44.4% in those collected from days 15 to 42. The most specific method (at 100%) was PCR and the least specific (at 89.1%) was IgM ELISA. Although we found PCR to be less sensitive than the serological tests over the course of the disease, our data indicate that PCR was the most sensitive in those initial serum samples presenting no specific antibodies detectable by any of the serological methods tested. We also recommend that PCR can be used in combination with serological tests as we found that this improves the sensitivity of the diagnosis of leptospirosis in the first phase of the disease (93.1–96.5%).
Leishmaniasis in Portugal: enzyme polymorphism of Leishmania infantum based on the identification of 213 strains
Authors: Campino L. , Pratlong F. , Abranches P. , Rioux J.‐A. , Santos‐Gomes G. , Alves‐Pires C. , Cortes S. , Ramada J. , Cristovão J. M. , Afonso M. O. , Dedet J. P.
Published: September 2006

This study reports isoenzyme polymorphism of Leishmania strains isolated in different regions of Portugal between 1982 and 2005. A total of 213 strains were obtained from cases of visceral and cutaneous leishmaniasis isolated from immunocompetent patients (adults and children) and immunocompromised adults, as well as from dogs and sandflies. Four zymodemes were identified: MON‐1, MON‐24, MON‐29 and MON‐80. Zymodeme MON‐1 was identified in 96.7% of the strains, predominating in both immunocompetent and immunocompromised human patients, and it was the only zymodeme isolated from dogs. Isoenzyme diversity in HIV‐infected patients was higher than in the immunocompetent group, in which all the strains from visceral leishmaniasis were MON‐1. The domestic dog was confirmed as the reservoir host of zoonotic leishmaniasis in Portugal and Phlebotomus perniciosus and Phlebotomus ariasi as vectors. The overall low enzyme polymorphism observed in the Portuguese foci contrasts with the neighbouring foci in Spain.
Suppression of exposure to malaria vectors by an order of magnitude using microbial larvicides in rural Kenya
Authors: Fillinger Ulrike , Lindsay Steven W.
Published: September 2006

Objective  To determine the contribution larviciding could make to reduce the burden of malaria, by conducting a trial of microbial larvicides in a 4.5 km2 area in and around a large village in rural western Kenya.

Method  The abundance of immature and adult mosquitoes was monitored for 12 months under baseline conditions. Then microbial larval control was implemented for 28 months. After the intervention, the abundance of immature and adult mosquitoes was monitored for a further 12 months.

Results  Of the 419 mosquito larval habitats identified, 336 (80%) originated from human activities. Application of Bacillus thuringiensis var. israelensis and Bacillus sphaericus larvicides reduced the proportion of aquatic habitats containing Anopheles larvae from 51% during non‐intervention periods to 7% during the intervention. The occurrence of late instar Anopheles in habitats was reduced from 39% and 33% in pre‐intervention and post‐intervention periods to 0.6% during intervention. Overall, larviciding reduced Anopheles larval density by 95% and human exposure to bites from adults by 92%. The estimated cost of providing this protection to the human population in the study area was less than US$ 0.90/person/year.

Conclusion  Appropriately applied microbial larvicides can substantially and cost‐effectively reduce human exposure to malaria in rural sub‐Saharan Africa.
Effectiveness of handwashing in preventing SARS: a review
Authors: Fung Isaac Chun‐Hai , Cairncross Sandy
Published: September 2006

This review examines the literature, including literature in Chinese, on the effectiveness of handwashing as an intervention against severe acute respiratory syndrome (SARS) transmission. Nine of 10 epidemiological studies reviewed showed that handwashing was protective against SARS when comparing infected cases and non‐infected controls in univariate analysis, but only in three studies was this result statistically significant in multivariate analysis. There is reason to believe that this is because most of the studies were too small. The evidence for the effectiveness of handwashing as a measure against SARS transmission in health care and community settings is suggestive, but not conclusive.
Assessing the relative contributions of phytochelatins and the cell wall to cadmium resistance in white lupin
Authors: Vázquez Saúl , Goldsbrough Peter , Carpena Ramón O
Published: September 2006

In response to Cd stress, higher plants utilise a number of defence systems, such as retention in cell walls, binding by organic molecules in the cytosol and sequestration in the vacuole. White lupin is a Cd‐resistant legume that is of interest for phytoremediation of acidified and Cd‐contaminated soils. The aim of this research was to evaluate the contributions of various mechanisms of Cd detoxification used by this species, focusing on cell‐wall retention and binding by thiol‐rich compounds. Retention of Cd by the cell wall of white lupin was well described by a Langmuir isotherm model. The percentage of total Cd adsorbed by the cell wall ranged from 29 to 47% in leaves, from 38 to 51% in stems and from 26 to 42% in roots depending on the Cd supply. Cadmium induced the synthesis of high levels of phytochelatins (PCs) in lupin plants, mainly in roots, with PC3 being the major PC. The amount of Cd complexed by thiols accounted for approximately 20% of the total Cd in leaves, 40% in stems and 20% in roots. Therefore, cell‐wall retention could account for more than twice the amount of Cd complexed by PCs in leaves and roots. In stems, both mechanisms contributed equally to Cd detoxification. These studies indicate that white lupin plants use cell‐wall binding and, secondarily, the production of PCs, as effective mechanisms of Cd detoxification.