Positive selection over the mitochondrial genome and its role in the diversification of gentoo penguins in response to adaptation in isolation.

Although mitochondrial DNA has been widely used in phylogeography, evidence has emerged that factors such as climate, food availability, and environmental pressures that produce high levels of stress can exert a strong influence on mitochondrial genomes, to the point of promoting the persistence of certain genotypes in order to compensate for the metabolic requirements of the local environment. As recently discovered, the gentoo penguins (Pygoscelis papua) comprise four highly divergent lineages across their distribution spanning the Antarctic and sub-Antarctic regions. Gentoo penguins therefore represent a suitable animal model to study adaptive processes across divergent environments. Based on 62 mitogenomes that we obtained from nine locations spanning all four gentoo penguin lineages, we demonstrated lineage-specific nucleotide substitutions for various genes, but only lineage-specific amino acid replacements for the ND1 and ND5 protein-coding genes. Purifying selection (dN/dS < 1) is the main driving force in the protein-coding genes that shape the diversity of mitogenomes in gentoo penguins. Positive selection (dN/dS > 1) was mostly present in codons of the Complex I (NADH genes), supported by two different codon-based methods at the ND1 and ND4 in the most divergent lineages, the eastern gentoo penguin from Crozet and Marion Islands and the southern gentoo penguin from Antarctica respectively. Additionally, ND5 and ATP6 were under selection in the branches of the phylogeny involving all gentoo penguins except the eastern lineage. Our study suggests that local adaptation of gentoo penguins has emerged as a response to environmental variability promoting the fixation of mitochondrial haplotypes in a non-random manner. Mitogenome adaptation is thus likely to have been associated with gentoo penguin diversification across the Southern Ocean and to have promoted their survival in extreme environments such as Antarctica. Such selective processes on the mitochondrial genome may also be responsible for the discordance detected between nuclear- and mitochondrial-based phylogenies of gentoo penguin lineages.

Phase transitions in huddling emperor penguins.

Emperor penguins (Aptenodytes forsteri) are highly adapted to the harsh conditions of the Antarctic winter: they are able to fast for up to 134 days during breeding. To conserve energy, emperor penguins form tight groups (huddles), which is key for their reproductive success. The effect of different meteorological factors on the huddling behaviour, however, is not well understood. Using time-lapse image recordings of an emperor penguin colony, we show that huddling can be described as a phase transition from a fluid to a solid state. We use the colony density as order parameter, and an apparent temperature that is perceived by the penguins as the thermodynamic variable. We approximate the apparent temperature as a linear combination of four meteorological parameters: ambient temperature, wind speed, global radiation and relative humidity. We find a wind chill factor of -2.9 °C/(ms -1), a humidity chill factor of -0.5°C/% rel. humidity, and a solar radiation heating factor of 0.3 °C//(Wm 2). In the absence of wind, humidity and solar radiation, the phase transition temperature (50% huddling probability) is -48.2°C for the investigated time period (May 2014). We propose that higher phase transition temperatures indicate a shrinking thermal insulation and thus can serve as a proxy for lower energy reserves of the colony, integrating pre-breeding foraging success at sea and energy expenditure at land due to environmental conditions. As current global change is predicted to have strong detrimental effects on emperor penguins within the next decades, our approach may thus contribute towards an urgently needed long-term monitoring system for assessing colony health.

[Abruptio placentae]. / Hématome rétroplacentaire.

Retroplacental haematoma (RPH) is a complication affecting 0.25 to 0.4% of all pregnancies and 4% of severe PEs. It is of acute onset, usually unpredictable and its symptoms are not specific: Isolated metrorrhagia, foetal distress, uterine hypertonicity. Clinical, biological and sonographic features suggesting a RPH can be early or late. Haemoconcentration and the forming of notches on Doppler examination of the uterus can appear weeks before the event, whereas raised D-Dimers and foetal tachycardia are identified within days of the event. Although Caesarian section reduces the perinatal death rate by 20 to 50% in a setting of RPH with a live foetus, vaginal delivery is indicated in cases of RPH with fetal demise, following the control of haemorrhagic shock, clotting disorders and uterine hypotonicity.

Inherited thrombophilias and unexplained pregnancy loss: an incident case-control study.

BACKGROUND: Despite an initial impressive impact, a critical appraisal of the link between pregnancy loss and inherited thrombophilias is currently growing. Furthermore, little is known about the paternal thrombophilic phenotype and pregnancy loss. OBJECTIVE: We sought an association between unexplained pregnancy loss and parental factor V Leiden (FVL) and Prothrombin G20210A (PTG) mutations. METHODS: Design - Incident case-control study. Setting- University Hospital of Brest (France). Patients - Women and their partners from the West Brittany area, consecutively referred for unexplained pregnancy losses (two or more consecutive losses at or before 21 weeks of gestation, or at least one later loss). Controls - Women and their partners with no history of pregnancy loss and at least one normal pregnancy, from the same geographic area, recruited using electoral lists. Statistical analysis - Comparison of FVL and PTG allele frequency between cases and controls using the chi-square test. Separate analyses were performed according to the type of pregnancy loss (early recurrent or later loss). RESULTS: 311 women (mean age: 32.8) and 284 of their partners were enrolled as cases while 599 women (mean age: 34.3) and 297 of their partners were recruited as controls. The prevalence of female, male or couple thrombophilic mutations was not statistically different between cases and controls whatever the definition of pregnancy loss retained. CONCLUSIONS: Presently, there is no clinical indication to routinely test for FVL and likely PTG mutations in women with early recurrent pregnancy loss. Moreover, our results did not reveal that paternal thrombophilic polymorphism should be further explored.

Strong evidence that skewed X-chromosome inactivation is not associated with recurrent pregnancy loss: an incident paired case control study.

BACKGROUND: Previous studies have reported conflicting results regarding recurrent pregnancy loss and skewed X-chromosome inactivation. Hence, we sought an association by carrying out a specifically designed incident paired case-control study with required statistical power. METHODS: Design incident 1:3 matched case-control study, from 2003 to 2007. SETTING: University Hospital of Brest. PATIENTS: Women, from the Brittany area, consecutively referred for at least two unexplained consecutive spontaneous abortions. CONTROLS: Women from the same geographic area, with no history of pregnancy loss and at least one normal pregnancy, recruited using electoral lists and then paired with cases, with respect to age, to within 1 year. INTERVENTION: Assessment of skewed X-chromosome inactivation. STATISTICAL ANALYSIS: Comparison of the ratio of >90% skewed X-chromosome inactivation by conditional logistic regression. RESULTS: Five hundred and forty-three controls (mean age: 34.3 years) were paired within 1 year to 200 cases. The cases (mean age: 33.6 years) had experienced between 2 and 14 consecutive losses (median 3). The rate of >90% skewed X-chromosome inactivation was not statistically different (P = 0.33, odds ratio: 0.58, 95% confidence interval: 0.19-1.77) between cases and paired controls, 2.27% versus 4.1%, respectively. CONCLUSIONS: We conclude that there is no association between skewed X-chromosome inactivation and recurrent pregnancy loss, defined as two or more unexplained consecutive spontaneous abortions.

Adjustments of gastric pH, motility and temperature during long-term preservation of stomach contents in free-ranging incubating king penguins.

Male king penguins are able to store undigested food in their stomach for up to 3 weeks during their incubation fast, which evidently implies some modification of their digestive process. Using small electronic recorders, we studied the change in gastric pH, motility and temperature during the first week of food storage. The pH could be maintained at values as high as 6 throughout the incubation fast, a pH that is unfavourable for avian gastric proteinase activity. Gastric motility was never completely inhibited but could be markedly reduced. Stomach temperature was maintained at around 38 degrees C. The fact that stomach temperature of incubating birds did not show a daily rhythmic fluctuation as seen in non-breeding birds could be due to temperature constraints on embryo development. Thus the present study demonstrates substantial adjustments of pH and gastric motility in incubating king penguins, which may contribute to the inhibition of digestive gastric processes.

Long-term effects of flipper bands on penguins.

Changes in seabird populations, and particularly of penguins, offer a unique opportunity for investigating the impact of fisheries and climatic variations on marine resources. Such investigations often require large-scale banding to identify individual birds, but the significance of the data relies on the assumption that no bias is introduced in this type of long-term monitoring. After 5 years of using an automated system of identification of king penguins implanted with electronic tags (100 adult king penguins were implanted with a transponder tag, 50 of which were also flipper banded), we can report that banding results in later arrival at the colony for courtship in some years, lower breeding probability and lower chick production. We also found that the survival rate of unbanded, electronically tagged king penguin chicks after 2-3 years is approximately twice as large as that reported in the literature for banded chicks.

[Breast cancer screening and medical consumption]. / Dépistage du cancer du sein et consommation médicale.

BACKGROUND: The use of general health services by women targeted by breast cancer screening campaigns, and its variations, are poorly known. A survey has been undertaken during one of these campaigns in a britton department. This study aimed at pointing out possible differences in use of general health services: search for an overuse by women whose screening resulted positive/negative, in relation to women whose screening resulted full negative; search for an overuse by women having participated, in relation to women within the age range of the screening campaign and not having wished to participate. METHODS: Three groups of women, aged 50 to 69 years, free of breast cancer, were compared. A random sample was drawn in each group, weighing for age in group D0. Inclusion of cases was undertaken between January 1995 (beginning of the screening campaign) and June 1996. Use of health services was recorded during the six months following the first screening test, using the health insurance services data. Expenses related to inpatient care were not recorded. RESULTS: The structure of age of the three groups was comparable. The proportion of women having requested no reimbursement was identical between the groups D+ and D-. For the D+ group, the average cost was 4,246 Francs per woman. It dropped to 3,871 Francs after deduction of expenses related to additional medical examinations following the finding of a positive screening test. It was 5% higher than the average cost in the D- group (3,698 Francs). The cost varied a great deal within each group and the differences observed between the groups were not statistically significant The proportion of women of the D0 group not having requested any reimbursement was significantly lower than those of the groups D- and D+, overall, and for the majority of the categories of expenditure. CONCLUSION: The result of the screening does not induce significant variation of use of general health services, apart from the expenses induced by the invalidation of the positive result. The group of women not having participated in screening includes a stronger proportion of both low and higher health services users.

[Radiologic analysis of known-interval cancers after 2 years of organized mass screening for breast cancer in Ille-et-Vilaine]. / Analyse radiologique des cancers d'intervalle connus apres deux ans de campagne de dépistage de masse organisé (DMO) du cancer du sein en Ille-et-Vilaine.

The first thirty-two known interval breast cancers (appearing within the first or second year after a negative screen) occurring during a two-year breast screening round were reviewed and the radiograms analyzed. Five classes were established: true interval cancers (13/32 cases), radiologically occult cancers (2/32), cancers with no specific sign (7/32), false negative cancers (5/32) and unclassifiable cancers (5/32). In more than 50% of the cases, there was no abnormality on the initial radiographic test, although the literature reports that the rate of false-negatives in interval cancers is less than 20%. Standard classification (by at least 3 readers) is very important to provide a possible explanation of cancer development. Action should be initiated to reduce their number.

Mass screening programs for breast cancer in France--average values of assessment criteria.

Breast cancer is the most common cancer in women worldwide. Many studies have been performed worldwide to assess the effectiveness of screening in terms of reduced mortality due to breast cancer. Since the end of 1989, 10 breast cancer mass screening programs using mammography have been carried out in France under the sponsorship of the National Fund for Health Prevention, Education, and Information (FNPEIS) from the National Health Insurance of Salaried Workers (CNAMTS). These 10 campaigns, which are on a district scale, are organized according to variable methods and are assessed using a common procedure. Four groups of criteria are measured in this procedure, which investigates the impact, quality, effectiveness, and costs of screening programs. The average and extreme values of each criterion as calculated from the campaigns are presented in this paper. In order to enlighten the judgment on the French results, a comparison with the international standards in force and with the results of foreign screening programs is proposed.

[Mass screening programs for breast cancer in France. Comparative evaluation]. / Les programmes de dépistage de masse du cancer du sein en France. Evaluation comparative.

OBJECTIVE: The purpose of this work was to comparatively assess the results of mass screening programs for breast cancer implemented in six French departments in 1986, within the scope of the National Fund for Health Prevention, Education and Information of the National Health Insurance Office of Salaried Workers. MATERIAL AND METHODS: The data collected by the screening centres were analyzed by ten assessment teams that were independent from the program promotion staff, all using the same evaluation form. A complementary population study performed in eight French districts then, allowed assessing the frequency of self-referred screening (mammography performed out of program). RESULTS: The rate of participation in screening programs, in relation to the invited population, ranged from 21 to 48%, according to the district (36% in average). This low participation was probably related to the extent of self-referred screening. In fact, 19 to 40% of women, according to the district, had previously had a screening mammographic coverage: rate was around 68% in women aged 50 to 69 years. Positive findings with mammography ranged from 4.5 to 15.8% (10.1% in average), while intervention rates ranged from 0.7 to 1.6% and detection rates from 3.8 to 6.2%. The ratio between benign tumors and cancers ranged from 0.7 to 2.1 according to the district. In order to enlighten the judgement on French results, we propose a comparison with the international standards in force. CONCLUSION: The various experiences with breast cancer screening in France show that this screening is technically feasible on the basis of existing medical structures. However, some criteria are still below the expected values, especially if compared with international standards. This result is probably accounted for by the high rate self-referred screening before age 40 in France. In these conditions, the question is whether extending breast cancer screening programs in France is an appropriate course of action.