The planar polarity gene strabismus regulates convergent extension movements in Xenopus

The signaling mechanisms that specify, guide and coordinate cell behavior during embryonic morphogenesis are poorly understood. We report that a Xenopus homolog of the Drosophila planar cell polarity gene strabismus (stbm) participates in the regulation of convergent extension, a critical morphogenetic process required for the elongation of dorsal structures in vertebrate embryos. Overexpression of Xstbm, which is expressed broadly in early development and subsequently in the nervous system, causes severely shortened trunk structures; a similar phenotype results from inhibiting Xstbm translation using a morpholino antisense oligo. Experiments with Keller explants further demonstrate that Xstbm can regulate convergent extension in both dorsal mesoderm and neural tissue. The specification of dorsal tissues is not affected. The Xstbm phenotype resembles those obtained with several other molecules with roles in planar polarity signaling, including Dishevelled and Frizzled-7 and -8. Unlike these proteins, however, Stbm has little effect on conventional Wnt/beta-catenin signaling in either frog or fly assays. Thus our results strongly support the emerging hypothesis that a vertebrate analog of the planar polarity pathway governs convergent extension movements.     

Comparison of methods for determination of vitamin B12 in microbial material

Three different methods for the measurement of vitamin B12 were compared: two spectrophotometric methods and an HPLC one. When the pure vitamin was used, the results obtained using all three methods were similar, but when samples from microbial material were used, the results were different. The HPLC method could distinguish the true vitamin B12 from the different vitamin B12 analogues whereas the spectrophotometric methods could not.     

Real-time imaging of the dynamics of secretory granules in growth cones

Secretory granules containing a hybrid protein consisting of the regulated secretory protein tissue plasminogen activator and an enhanced form of green fluorescent protein were tracked at high spatial resolution in growth cones of differentiated PC12 cells. Tracking shows that granules, unlike synaptic vesicles, generally are mobile in growth cones. Quantitative analysis of trajectories generated by granules revealed two dominant modes of motion: diffusive and directed. Diffusive motion was observed primarily in central and peripheral parts of growth cones, where most granules diffused two to four orders of magnitude more slowly than comparably sized spheres in dilute solution. Directed motion was observed primarily in proximal parts of growth cones, where a subset of granules underwent rapid, directed motion at average speeds comparable to those observed for granules in neurites. This high-resolution view of the dynamics of secretory granules in growth cones provides insight into granule organization and release at nerve terminals. In particular, the mobility of granules suggests that granules, unlike synaptic vesicles, are not tethered stably to cytoskeletal structures in nerve terminals. Moreover, the slow diffusive nature of this mobility suggests that secretory responses involving centrally distributed granules in growth cones will occur slowly, on a time scale of minutes or longer.     

Enzymes that hydrolyze adenine nucleotides in chronic renal failure: relationship between hemostatic defects and renal failure severity

The activities of the enzymes NTPDase (E.C.3.6.1.5, apyrase, ATP diphosphohydrolase, ecto-CD 39) and 5'-nucleotidase (E.C.3.1.3.5, CD 73) were analyzed in platelets from patients with chronic renal failure (CRF), both undergoing hemodialysis treatment (HD) and not undergoing hemodialysis (ND), as well as from a control group. The results showed an increase in platelet NTPDase activity in CRF patients on HD treatment (52.88%) with ATP as substrate (P<0.0001). ADP hydrolysis was decreased (33.68% and 39.75%) in HD and ND patients, respectively. In addition, 5'-nucleotidase activity was elevated in the HD (160%) and ND (81.49%) groups when compared to the control (P<0.0001). Significant correlation was found among ATP, ADP and AMP hydrolysis and plasma creatinine and urea levels (P<0.0001). Patients were compared statistically according the time of hemodialysis treatment. We found enhanced NTPDase and 5'-nucleotidase activities between 49 and 72 months on HD patients. Our result suggests the existence of alterations in nucleotide hydrolysis in platelets of CRF patients. Possibly, this altered nucleotide hydrolysis could contribute to hemostasis abnormalities found in CRF.     

Substitution of feline leukemia virus long terminal repeat sequences into murine leukemia virus alters the pattern of insertional activation and identifies new common insertion sites

The recombinant retrovirus, MoFe2-MuLV (MoFe2), was constructed by replacing the U3 region of Moloney murine leukemia virus (M-MuLV) with homologous sequences from the FeLV-945 LTR. NIH/Swiss mice neonatally inoculated with MoFe2 developed T-cell lymphomas of immature thymocyte surface phenotype. MoFe2 integrated infrequently (0 to 9%) near common insertion sites (CISs) previously identified for either parent virus. Using three different strategies, CISs in MoFe2-induced tumors were identified at six loci, none of which had been previously reported as CISs in tumors induced by either parent virus in wild-type animals. Two of the newly identified CISs had not previously been implicated in lymphoma in any retrovirus model. One of these, designated 3-19, encodes the p101 regulatory subunit of phosphoinositide-3-kinase-gamma. The other, designated Rw1, is predicted to encode a protein that functions in the immune response to virus infection. Thus, substitution of FeLV-945 U3 sequences into the M-MuLV long terminal repeat (LTR) did not alter the target tissue for M-MuLV transformation but significantly altered the pattern of CIS utilization in the induction of T-cell lymphoma. These observations support a growing body of evidence that the distinctive sequence and/or structure of the retroviral LTR determines its pattern of insertional activation. The findings also demonstrate the oligoclonal nature of retrovirus-induced lymphomas by demonstrating proviral insertions at CISs in subdominant populations in the tumor mass. Finally, the findings demonstrate the utility of novel recombinant retroviruses such as MoFe2 to contribute new genes potentially relevant to the induction of lymphoid malignancy.     

Phase 1 trial of the oral AKT inhibitor MK-2206 plus carboplatin/paclitaxel, docetaxel, or erlotinib in patients with advanced solid tumors

Background

Inhibition of AKT with MK-2206 has demonstrated synergism with anticancer agents. This phase 1 study assessed the MTD, DLTs, PK, and efficacy of MK-2206 in combination with cytotoxic and targeted therapies.

Methods

Advanced solid tumor patients received oral MK-2206 45 or 60 mg (QOD) with either carboplatin (AUC 6.0) and paclitaxel 200 mg/m² (arm 1), docetaxel 75 mg/m² (arm 2), or erlotinib 100 or 150 mg daily (arm 3); alternative schedules of MK-2206 135-200 mg QW or 90-250 mg Q3W were also tested.

Results

MTD of MK-2206 (N?=?72) was 45 mg QOD or 200 mg Q3W (arm 1); MAD was 200 mg Q3W (arm 2) and 135 mg QW (arm 3). DLTs included skin rash (arms 1, 3), febrile neutropenia (QOD, arms 1, 2), tinnitus (Q3W, arm 2), and stomatitis (QOD, arm 3). Common drug-related toxicities included fatigue (68%), nausea (49%), and rash (47%). Two patients with squamous cell carcinoma of the head and neck (arm 1; Q3W) demonstrated a complete and partial response (PR); additional PRs were observed in patients (1 each) with melanoma, endometrial, neuroendocrine prostate, NSCLC, and cervical cancers. Six patients had stable disease ≥6 months.

Conclusion

MK-2206 plus carboplatin and paclitaxel, docetaxel, or erlotinib was well-tolerated, with early evidence of antitumor activity.

Trial registration

ClinicalTrials.gov: NCT00848718.     

Promotional tone in reviews of menopausal hormone therapy after the Women's Health Initiative: an analysis of published articles

Background

Even after the Women''s Health Initiative (WHI) found that the risks of menopausal hormone therapy (hormone therapy) outweighed benefit for asymptomatic women, about half of gynecologists in the United States continued to believe that hormones benefited women''s health. The pharmaceutical industry has supported publication of articles in medical journals for marketing purposes. It is unknown whether author relationships with industry affect promotional tone in articles on hormone therapy. The goal of this study was to determine whether promotional tone could be identified in narrative review articles regarding menopausal hormone therapy and whether articles identified as promotional were more likely to have been authored by those with conflicts of interest with manufacturers of menopausal hormone therapy.

Methods and Findings

We analyzed tone in opinion pieces on hormone therapy published in the four years after the estrogen-progestin arm of the WHI was stopped. First, we identified the ten authors with four or more MEDLINE-indexed reviews, editorials, comments, or letters on hormone replacement therapy or menopausal hormone therapy published between July 2002 and June 2006. Next, we conducted an additional search using the names of these authors to identify other relevant articles. Finally, after author names and affiliations were removed, 50 articles were evaluated by three readers for scientific accuracy and for tone. Scientific accuracy was assessed based on whether or not the findings of the WHI were accurately reported using two criteria: (1) Acknowledgment or lack of denial of the risk of breast cancer diagnosis associated with hormone therapy, and (2) acknowledgment that hormone therapy did not benefit cardiovascular disease endpoints. Determination of promotional tone was based on the assessment by each reader of whether the article appeared to promote hormone therapy. Analysis of inter-rater consistency found moderate agreement for scientific accuracy (κ = 0.57) and substantial agreement for promotional tone (κ = 0.65). After discussion, readers found 86% of the articles to be scientifically accurate and 64% to be promotional in tone. Themes that were common in articles considered promotional included attacks on the methodology of the WHI, arguments that clinical trial results should not guide treatment for individuals, and arguments that observational studies are as good as or better than randomized clinical trials for guiding clinical decisions. The promotional articles we identified also implied that the risks associated with hormone therapy have been exaggerated and that the benefits of hormone therapy have been or will be proven. Of the ten authors studied, eight were found to have declared payment for speaking or consulting on behalf of menopausal hormone manufacturers or for research support (seven of these eight were speakers or consultants). Thirty of 32 articles (90%) evaluated as promoting hormone therapy were authored by those with potential financial conflicts of interest, compared to 11 of 18 articles (61%) by those without such conflicts (p = 0.0025). Articles promoting the use of menopausal hormone therapy were 2.41 times (95% confidence interval 1.49–4.93) as likely to have been authored by authors with conflicts of interest as by authors without conflicts of interest. In articles from three authors with conflicts of interest some of the same text was repeated word-for-word in different articles.

Conclusion

There may be a connection between receiving industry funding for speaking, consulting, or research and the publication of promotional opinion pieces on menopausal hormone therapy. Please see later in the article for the Editors'' Summary     

Intravaginal practices, bacterial vaginosis, and HIV infection in women: individual participant data meta-analysis

Background

Identifying modifiable factors that increase women''s vulnerability to HIV is a critical step in developing effective female-initiated prevention interventions. The primary objective of this study was to pool individual participant data from prospective longitudinal studies to investigate the association between intravaginal practices and acquisition of HIV infection among women in sub-Saharan Africa. Secondary objectives were to investigate associations between intravaginal practices and disrupted vaginal flora; and between disrupted vaginal flora and HIV acquisition.

Methods and Findings

We conducted a meta-analysis of individual participant data from 13 prospective cohort studies involving 14,874 women, of whom 791 acquired HIV infection during 21,218 woman years of follow-up. Data were pooled using random-effects meta-analysis. The level of between-study heterogeneity was low in all analyses (I ² values 0.0%–16.1%). Intravaginal use of cloth or paper (pooled adjusted hazard ratio [aHR] 1.47, 95% confidence interval [CI] 1.18–1.83), insertion of products to dry or tighten the vagina (aHR 1.31, 95% CI 1.00–1.71), and intravaginal cleaning with soap (aHR 1.24, 95% CI 1.01–1.53) remained associated with HIV acquisition after controlling for age, marital status, and number of sex partners in the past 3 months. Intravaginal cleaning with soap was also associated with the development of intermediate vaginal flora and bacterial vaginosis in women with normal vaginal flora at baseline (pooled adjusted odds ratio [OR] 1.24, 95% CI 1.04–1.47). Use of cloth or paper was not associated with the development of disrupted vaginal flora. Intermediate vaginal flora and bacterial vaginosis were each associated with HIV acquisition in multivariable models when measured at baseline (aHR 1.54 and 1.69, p<0.001) or at the visit before the estimated date of HIV infection (aHR 1.41 and 1.53, p<0.001), respectively.

Conclusions

This study provides evidence to suggest that some intravaginal practices increase the risk of HIV acquisition but a direct causal pathway linking intravaginal cleaning with soap, disruption of vaginal flora, and HIV acquisition has not yet been demonstrated. More consistency in the definition and measurement of specific intravaginal practices is warranted so that the effects of specific intravaginal practices and products can be further elucidated. Please see later in the article for the Editors'' Summary     

Spathaspora brasiliensis sp. nov., Spathaspora suhii sp. nov., Spathaspora roraimanensis sp. nov. and Spathaspora xylofermentans sp. nov., four novel d-xylose-fermenting yeast species from Brazilian Amazonian forest

Four new d-xylose fermenting yeast species of the clade Spathaspora were recovered from rotting-wood samples in a region of Amazonian forest, Northern Brazil. Three species produced unconjugated asci with a single elongated ascospore with curved ends. These species are described as Spathaspora brasiliensis, Spathaspora suhii and Spathaspora roraimanensis. Two isolates of an asexually reproducing species belonging to the Spathaspora clade were also obtained and they are described as Spathaspora xylofermentans. All these species are able to ferment d-xylose during aerobic batch growth in rich YP (1 % yeast extract, 2 % peptone and 2 % D-xylose) medium, albeit with differing efficiencies. The type strains are Spathaspora brasiliensis sp. nov UFMG-HMD19.3 (=CBMAI 1425=CBS 12679), Spathaspora suhii sp. nov. UFMG-XMD16.2 (=CBMAI 1426=CBS 12680), Spathaspora roraimanensis sp. nov. UFMG-XMD23.2 (CBMAI 1427=CBS 12681) and Spathaspora xylofermentans sp. nov. UFMG-HMD23.3 (=CBMAI 1428=CBS 12682).