Mechanisms of reproductive isolation between an ant species of hybrid origin and one of its parents.

The establishment of new species by hybridization is difficult because it requires the development of reproductive isolation (RI) in sympatry to escape the homogenizing effects of gene flow from the parental species. Here we investigated the role of two pre- and two postzygotic mechanisms of RI in a system comprising two interdependent Pogonomyrmex harvester ant lineages (the H1 and H2 lineages) of hybrid origin and one of their parental species (P. rugosus). Similar to most other ants, P. rugosus is characterized by an environmental system of caste determination with female brood developing either into queens or workers depending on nongenetic factors. By contrast, there is a strong genetic component to caste determination in the H1 and H2 lineages because the developmental fate of female brood depends on the genetic origin of the parents, with interlineage eggs developing into workers and intralineage eggs developing into queens. The study of a mixed mating aggregation revealed strong differences in mating flight timing between P. rugosus and the two lineages as a first mechanism of RI. A second important prezygotic mechanism was assortative mating. Laboratory experiments also provided support for one of the two investigated mechanisms of postzygotic isolation. The majority of offspring produced from the few matings between P. rugosus and the lineages aborted at the egg stage. This hybrid inviability was under maternal influence, with hybrids produced by P. rugosus queens being always inviable whereas a small proportion of H2 lineage queens produced large numbers of adult hybrid offspring. Finally, we found no evidence that genetic caste determination acted as a second postzygotic mechanism reducing gene flow between P. rugosus and the H lineages. The few viable P. rugosus-H hybrids were not preferentially shunted into functionally sterile workers but developed into both workers and queens. Overall, these results reveal that the nearly complete (99.5%) RI between P. rugosus and the two hybrid lineages stems from the combination of two typical prezygotic mechanisms (mating time divergence and assortative mating) and one postzygotic mechanism (hybrid inviability).

Treatment of symphysitis pubis with one unique iv injection of Ibandronate: report of two cases

Objective: Osteitis pubis is a noninfectious painful inflammatorydisorder of the symphysis pubis. Etiologic factors are numerous, themost common are: osseous extension of adductor, enthesis due tosport overuse, irritation after urological and abdominal procedures,and systemic inflammatory disorders in particularspondylarthropathies. Many cases are idiopathic. The symptomsconsist of regional chronic mechanical and sometime nocturnal pain.Diagnosis is usually confirmed by either bone scintigraphy or by MRI.There are no standard treatments but conservative approachesincluding rest and NSAIDS are generally recommended. In 2001, agood clinical and radiological response of three refractory cases with3 to 6 monthly perfusions of pamidronate was reported [1].Ibandronate is a much more powerful and long-lasting bisphosphonatethan pamidronate, and has not yet been reported in literature to ourknowledge in this indication.Patients and Methods: We present two cases of idiopathic origin:one woman (63 years old) and one man (36 years old).The symptomswere present >3 months in the first patient and one year in the second.The diagnosis was confirmed by MRI which showed bone edemaon both sizes of symphysis and in the second case bony erosionsadjacent to the joint were seen. Both cases failed to respond toconservative measures. Both patients received one single direct ivInjection of 3 mg of Ibandronate.Results: The injections resulted in a rapid (within a few days)resolution of pain that lasted more than 6 months in both patients.No side effects were observed. In the first case, an isotope bone scanperformed 4 months after the injection showed no residual uptake. Thesecond patient had a repeated MRI after 6 months. It demonstrated anattenuation of bone edema compared to the first MRI.Conclusion: IV Ibandronate may constitute a safe and effectivetreatment option for patients with refractory osteitis pubis.References1 Maksymowych WP, Aaron SL, Russell AS. Treatment of refractorysymphysitis pubis with intravenous pamidronate. J Rheumatol.2001;28(12):2754, 2001.

Altruism across disciplines: one word, multiple meanings

Altruism is a deep and complex phenomenon that is analysed by scholars of various disciplines, including psychology, philosophy, biology, evolutionary anthropology and experimental economics. Much confusion arises in current literature because the term altruism covers variable concepts and processes across disciplines. Here we investigate the sense given to altruism when used in different fields and argumentative contexts. We argue that four distinct but related concepts need to be distinguished: (a) psychological altruism, the genuine motivation to improve others' interests and welfare; (b) reproductive altruism, which involves increasing others' chances of survival and reproduction at the actor's expense; (c) behavioural altruism, which involves bearing some cost in the interest of others; and (d) preference altruism, which is a preference for others' interests. We show how this conceptual clarification permits the identification of overstated claims that stem from an imprecise use of terminology. Distinguishing these four types of altruism will help to solve rhetorical conflicts that currently undermine the interdisciplinary debate about human altruism.

Evolution of vitellogenin genes: comparative analysis of the nucleotide sequences downstream of the transcription initiation site of four Xenopus laevis and one chicken gene.

Electron microscopic analysis of heteroduplexes between the most distantly related Xenopus vitellogenin genes (A genes X B genes) has revealed the distribution of homologous regions that have been preferentially conserved after the duplication events that gave rise to the multigene family in Xenopus laevis. DNA sequence analysis was limited to the region downstream of the transcription initiation site of the Xenopus genes A1, B1 and B2 and a comparison with the Xenopus A2 and the major chicken vitellogenin gene is presented. Within the coding regions of the first three exons, nucleotide substitutions resulting in amino acid changes accumulate at a rate similar to that observed in globin genes. This suggests that the duplication event which led to the formation of the A and B ancestral genes in Xenopus laevis occurred about 150 million years ago. Homologous exons of the A1-A2 and B1-B2 gene pairs, which formed about 30 million years ago, show a quite similar sequence divergence. In contrast, A1-A2 homologous introns seem to have evolved much faster than their B1-B2 counterparts.

A one-year monitoring of nicotine use in sport: frontier between potential performance enhancement and addiction issues

Tobacco consumption is a global epidemic responsible for a vast burden of disease. With pharmacological properties sought-after by consumers and responsible for addiction issues, nicotine is the main reason of this phenomenon. Accordingly, smokeless tobacco products are of growing popularity in sport owing to potential performance enhancing properties and absence of adverse effects on the respiratory system. Nevertheless, nicotine does not appear on the 2011 World Anti-Doping Agency (WADA) Prohibited List or Monitoring Program by lack of a comprehensive large-scale prevalence survey. Thus, this work describes a one-year monitoring study on urine specimens from professional athletes of different disciplines covering 2010 and 2011. A method for the detection and quantification of nicotine, its major metabolites (cotinine, trans-3-hydroxycotinine, nicotine-N′-oxide and cotinine-N-oxide) and minor tobacco alkaloids (anabasine, anatabine and nornicotine) was developed, relying on ultra-high pressure liquid chromatography coupled to triple quadrupole mass spectrometry (UHPLC-TQ-MS/MS). A simple and fast dilute-and-shoot sample treatment was performed, followed by hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS) operated in positive electrospray ionization (ESI) mode with multiple reaction monitoring (MRM) data acquisition. After method validation, assessing the prevalence of nicotine consumption in sport involved analysis of 2185 urine samples, accounting for 43 different sports. Concentrations distribution of major nicotine metabolites, minor nicotine metabolites and tobacco alkaloids ranged from 10 (LLOQ) to 32,223, 6670 and 538 ng/mL, respectively. Compounds of interest were detected in trace levels in 23.0% of urine specimens, with concentration levels corresponding to an exposure within the last three days for 18.3% of samples. Likewise, hypothesizing conservative concentration limits for active nicotine consumption prior and/or during sport practice (50 ng/mL for nicotine, cotinine and trans-3-hydroxycotinine and 25 ng/mL for nicotine-N′-oxide, cotinine-N-oxide, anabasine, anatabine and nornicotine) revealed a prevalence of 15.3% amongst athletes. While this number may appear lower than the worldwide smoking prevalence of around 25%, focusing the study on selected sports highlighted more alarming findings. Indeed, active nicotine consumption in ice hockey, skiing, biathlon, bobsleigh, skating, football, basketball, volleyball, rugby, American football, wrestling and gymnastics was found to range between 19.0 and 55.6%. Therefore, considering the adverse effects of smoking on the respiratory tract and numerous health threats detrimental to sport practice at top level, likelihood of smokeless tobacco consumption for performance enhancement is greatly supported.

Patterns of pain freedom response in 497 cases with classical trigeminal neuralgia and at least one year of follow-up treated by gamma knife radiosurgery

Purpose: To identify patterns of initially pain freedom response in patients with classical trigeminal neuralgia (CTN) with Gamma Knife surgery (GKS) and to compare their associated hypoesthesia and recurrence rates. Methods: In this study we analysed only 497 patients treated between July 1992 and November 2010, with a follow-up longer than 1 year, after excluding megadolichobasilar artery and multiple sclerosis related trigeminal neuralgia, as well as the second GKS treatments so as to have only cases with CTN and single radiosurgical treatment. GKS using a Gamma Knife (model B or C or Perfexion) was performed, based on both MRI and computer tomography (CT) targeting. A single 4-mm isocenter was positioned in the cisternal portion of the trigeminal nerve at a median distance of 7.8 mm (range 4.5-14) anteriorly to the emergence of the nerve. A median maximum dose of 85 Gy (range 70-90) was delivered. After empiric methods but also by using a chart with clear cut-off periods of pain free distribution, we were able to divide the initially pain free patients into 3 separate groups: within the first 48 hours, after 48 hours till 30 days and after 30 days, respectively. Results: The median follow- up period was 43.75 months (range 12-174.41). Four hundred and fifty-four patients (91.75%) were initially pain free in a median time of 10 days (range 1-459): 169 (37.2%) became pain free within the first 48 hours (pf<=48 h), compared to 194 (42.8%) between the 3-rd day and the day 30 (pf (>48 h, <=30 d)), inclusively and 91 (20%) patients after 30 days (pf>30d). Differences in terms of postoperative hypoesthesia were found with a p value of 0.014 as follows: the group pf<=48 h had 18 (13.7%) compared to pf (>48 h, <=30 d) with 30 (19%) and pf>30d with 22 (30.5%) patients developing a postoperative GKS hypoesthesia. One hundred and fifty seven (34.4%) patients initially pain free experienced a recurrence with a median delay of 24 months (range 0.62-150.06). There were no statistically significant differences between the three groups concerning recurrence (p value of 0.515). Conclusions: An important number of patients (169 cases, 37.2%) became pain free in the first 48 hours. Hypoesthesia rate was higher within the group becoming pain free after 30 days with a statistically significant difference between the three populations (p= 0.014). Further analysis will eventually help to elucidate the differences observed among groups.

Does the mechanical work in running change during the VO2 slow component?

PURPOSE: The origin of the slow component is not fully understood. The mechanical hypothesis is one of the potential factors, because an increase in external mechanical work with fatigue was previously reported for a constant velocity run. The purpose of this study was to determine whether a change in mechanical work could occur during the development of the VO2 slow component under the effect of fatigue. METHODS: Twelve regional-level competitive runners performed a square-wave transition, corresponding to 95% of the speed associated with peak VO2 obtained during an incremental test. The VO2 response was fit with a classical model including two exponential functions. A specific treadmill with three-dimensional force transducers was used to measure the ground reaction force. Kinetic work (W(kin)), potential work (W(pot)), external work (W(ext)), and an index of internal work (W(int)) per unit of distance were quantified continuously. RESULTS: During the slow component of VO2, a significant increase in W (P< 0.01), no change in W, and a significant decrease in W and W index (P< 0.05, P< 0.001, respectively) were observed. CONCLUSION: The present study showed that the slow component of VO2 did not result partly from a change in mechanical work under the effect of fatigue. Nevertheless, the decrease in stride frequency (P< 0.001) and contact time (P< 0.001) suggested an alternative mechanical explanation. The slow component during running may be due to the cost of generating force or to alterations in the storage and recoil of elastic energy, and not to the external mechanical work.

Kenny syndrome: evidence for idiopathic hypoparathyroidism in two patients and for abnormal parathyroid hormone in one.

We report three unrelated patients with Kenny syndrome. Clinical symptoms included severe dwarfism, with internal cortical thickening and medullary stenosis of the tubular bones, normal bone age, macrocephaly, absent diploic space, delayed closure of the anterior fontanel, and normal intelligence; two of the patients had hyperopia and papillary edema. The patients also had episodic hypocalcemic tetany and low serum levels of magnesium. In two patients the diagnosis of idiopathic hypoparathyroidism was established on the basis of undetectable serum parathyroid hormone (PTH) levels (N- and C-terminal RIAs); one of these had normal urinary cyclic adenosine monophosphate (cAMP) response to exogenous PTH. Circulating calcitonin was undetectable in either patient. In a third patient, who had abnormal body proportions, serum levels of PTH were increased in an RIA detecting predominantly intact PTH (N-RIA) and undetectable in another RIA recognizing carboxy-terminal fragments (C-RIA). Administration of PTH promptly increased urinary cAMP excretion. In this patient, serum levels of calcitonin were increased, whereas values for 25-OHD and 1,25(OH)2D were normal.