Time Space Translation: A Hox Mechanism for Vertebrate A-P Patterning

The vertebrate A-P axis is a time axis. The head is made first and more and more posterior levels are made at later and later stages. This is different to the situation in most other animals, for example, in Drosophila. Central to this timing is Hox temporal collinearity (see below). This occurs rarely in the animal kingdom but is characteristic of vertebrates and is used to generate the primary axial Hox pattern using time space translation and to integrate successive derived patterns (see below). This is thus a different situation than in Drosophila, where the primary pattern guiding Hox spatial collinearity is generated externally, by the gap and segmentation genes.     

Molecular and antigenic characterization of reassortant H3N2 viruses from turkeys with a unique constellation of pandemic H1N1 internal genes

Triple reassortant (TR) H3N2 influenza viruses cause varying degrees of loss in egg production in breeder turkeys. In this study we characterized TR H3N2 viruses isolated from three breeder turkey farms diagnosed with a drop in egg production. The eight gene segments of the virus isolated from the first case submission (FAV-003) were all of TR H3N2 lineage. However, viruses from the two subsequent case submissions (FAV-009 and FAV-010) were unique reassortants with PB2, PA, nucleoprotein (NP) and matrix (M) gene segments from 2009 pandemic H1N1 and the remaining gene segments from TR H3N2. Phylogenetic analysis of the HA and NA genes placed the 3 virus isolates in 2 separate clades within cluster IV of TR H3N2 viruses. Birds from the latter two affected farms had been vaccinated with a H3N4 oil emulsion vaccine prior to the outbreak. The HAl subunit of the H3N4 vaccine strain had only a predicted amino acid identity of 79% with the isolate from FAV-003 and 80% for the isolates from FAV-009 and FAV-0010. By comparison, the predicted amino acid sequence identity between a prototype TR H3N2 cluster IV virus A/Sw/ON/33853/2005 and the three turkey isolates from this study was 95% while the identity between FAV-003 and FAV-009/10 isolates was 91%. When the previously identified antigenic sites A, B, C, D and E of HA1 were examined, isolates from FAV-003 and FAV-009/10 had a total of 19 and 16 amino acid substitutions respectively when compared with the H3N4 vaccine strain. These changes corresponded with the failure of the sera collected from turkeys that received this vaccine to neutralize any of the above three isolates in vitro.     

Willingness of patients to change surgeons for a shorter waiting time for joint arthroplasty

Background

To improve access to care, many jurisdictions have proposed waiting-time benchmarks and guarantees. We assessed the willingness of patients to consider changing their surgeon to one with a shorter waiting time for arthroplasty.

Methods

We mailed a questionnaire to 2 random samples of patients who either were awaiting hip or knee replacement arthroplasty or had had one of these procedures within the preceding 3–12 months. We used logistic regression to assess the determinants of patients'' likelihood to consider changing surgeons.

Results

Of 1200 responses from a sample of 2000, 557 (46%) were from patients awaiting surgery and 643 (54%) were from people who had undergone surgery. The mean age of respondents was 69.9 years (standard deviation 10.8), and 682 (57%) were women. The median waiting time for surgery was 8 months. Overall, 753 (63%) of the patients were unlikely to consider changing surgeons. Increased likelihood of changing surgeons was associated with male sex (adjusted odds ratio [OR] 1.49, 95% confidence interval [CI] 1.10–2.02), a high school education or higher (OR 1.73, 95% CI 1.15– 2.62) and having already undergone surgery (OR 1.71, 95% CI 1.19– 2.46). Decreased likelihood was associated with preference for a particular surgeon before referral (OR 0.57, 95% CI 0.42– 0.79), a better score on the EuroQol (EQ-5D) index (a measure of health-related quality of life) (OR 0.39, 95% CI 0.24– 0.66), perception that the waiting time to see the surgeon was acceptable (OR 0.50, 95% CI 0.36–0.70), perception that the waiting time to surgery was acceptable (OR 0.62, 95% CI 0.43–0.91) and perceived fairness of treatment (OR 0.53, 95% CI 0.36– 0.78).

Interpretation

Despite long waits for surgery, most patients, if given the choice, would be unlikely to change their surgeon to one with a shorter waiting time.Long waiting times for elective surgery are a concern in countries with publicly funded health care systems.¹ To try to improve access, governments in Canada and some other countries in the Organisation for Economic Co-operation and Development have proposed or implemented waiting-time benchmarks and care guarantees.² These benchmarks, typically between 3 and 12 months, usually refer to the time between assessment by a specialist and in-patient treatment.³Waiting times for hip and knee arthroplasty are perceived as excessive in many countries, including Canada.^4–6 In 2005, Canada''s federal, provincial and territorial health ministers set a target waiting time of 26 weeks for hip and knee arthroplasty, and in 2007 they agreed to establish waiting-time guarantees by 2010 in selected priority areas, including joint arthroplasty.⁷ A waiting-time guarantee implies that, if necessary medical treatment for a publicly insured service is not available within a medically acceptable timeframe, patients may receive treatment at another facility, even outside their home province, at public expense. This change in the location of treatment implies that another surgeon would perform the surgery. However, patients are not always willing to accept re-referral to a provider with a shorter waiting time.^8–12Most other studies investigating patient choice in the context of long waiting times have referred to the choice of an alternative hospital rather than the choice of an alternative surgeon. Even though many patients may indicate that they are willing to travel to another hospital, fewer actually choose such a change.¹¹ In addition to waiting time,^8,13 other factors influencing provider choice are the hospital''s reputation, follow-up care and travel time.^8,13,14 Little is known about what factors patients consider and what information they want and can use when choosing a provider.^11,15We sought to assess patients'' willingness to consider changing to a surgeon with a shorter waiting time for hip and knee arthroplasty. We formulated the following research questions: Would patients consider changing to a surgeon with shorter waiting times? What factors influence patients'' willingness to consider changing surgeons? Do patients waiting for surgery have a different perspective than patients who have already undergone their surgery?     

NITPICK: peak identification for mass spectrometry data

Background  

The reliable extraction of features from mass spectra is a fundamental step in the automated analysis of proteomic mass spectrometry (MS) experiments.     

PA,a stress-induced short cut to switch-on ethylene signalling by switching-off CTR1?

Constitutive triple response 1 (CTR1) is a protein kinase that represses plant responses to ethylene. Recently, we have shown that CTR1 function is negatively regulated by the lipid second messenger phosphatidic acid (PA) in vitro.¹ PA was shown to inhibit (1) CTR1''s protein kinase activity, (2) the intramolecular interaction between N-terminus and kinase domain, and (3) the interaction of CTR1 with the ethylene receptor ETR1. PA typically accumulates within minutes in response to biotic or abiotic stresses, which are known to induce ethylene formation. Although long-term treatment with ethephon does stimulate PA accumulation, our results show no fast increase in PA in response to ethylene. A speculative model is presented which explains how stress-induced PA formation could switch on downstream ethylene responses via interaction of the lipid with CTR1.Key words: lipid signaling, phosphatidic acid, ethylene, constitutive triple response 1, plant stress signaling, protein kinase, phospholipase D     

The utility of the morphological variation of pollen for resolving the evolutionary history of Billia (subfam. Hippocastanoideae,Sapindaceae)

In this study, we examined the utility of pollen morphology for resolving questions about the evolutionary history of Billia, which is a poorly known genus of Neotropical trees. Billia has been traditionally circumscribed with two species and treated as sister to Aesculus L. However, the number of species in Billia is uncertain, because the genus exhibits abundant morphological diversity but little discontinuous variation. Therefore, Billia may be monotypic and highly polymorphic, or it may have two species with blurred boundaries due to incipient speciation and/or hybridization. Moreover, one recent molecular phylogenetic study shows Billia nested withinAesculus. Our work sought to address the following questions: (i) Are there discontinuities in the pollen of Billia that may suggest species boundaries? (ii) Does the pollen of Billia show evidence for inter-specific hybridization? (iii) Do the exine morphology and size of pollen in Billia differ from those in Aesculus? Our results from scanning electron microscopy showed that pollen exine morphology is not taxonomically informative in Billia but that there are significant differences in pollen size between red- and white-flowered individuals. Thus, our pollen data support the utility of flower color in Billia for species delimitation. Our assessments of pollen viability do not support hybridization in the genus, but cannot be used to rule it out. Finally, pollen exine morphology may lend some support to an evolutionary origin ofBillia within eastern North American Aesculus. In contrast, data on pollen size suggest that Billia may belong in a topological position outside of Aesculus.     

Chemoselective Synthesis of Dithymidine Phosphorothioate in Solution Using O-Protected Thiophosphate Monomers

Abstract

Diastereomerically pure O-protected thymine monothioate nucleotide (I) is efficiently coupled to protected thymidine (II) in a chemoselective, but not stereoselective manner, to give dithymidine phosphorothioates (III).