Relationship of mating systems and metabolic rate with cycle length of spermatogenesis and sperm production rate in shrews

SUMMARY : The shrews are among the most ancient of living eutherian mammals. They represent an interesting comparative model because of their extreme divergent species. The two shrew subfamilies, Soricinae and Crocidurinae are characterized by fundamental differences concerning their metabolic rates, litter size, period of gestation and different mating pattern. In this study we established and compared the sperm characteristics in four species of different genera of shrews (Sorex araneus, Neomys fodiens, Crocidura russula and Suncus murinus) in the context of the sperm competition hypothesis. The sperm competition concerns the competition between ejaculates of different males for fertilization of ova of a female within a single estrus period. As expected, a greater relative testis size (indicating the importance of polyandry) was associated with a higher number of cauda epididymal spermatozoa, higher level of circulating testosterone and a higher percentage of progressive sperm motility. In addition, we investigated if the basal metabolic rate (BMR) and relative testis size (RTS) may be correlated with the cycle length of spermatogenesis. In this purpose, we determined and compared the cycle length of spermatogenesis in six species of shrews belonging to two subfamilies: Soiricinae (Sorex araneus, Sorex coronatus, Sorex minutus, Neomys fodiens) and Crocidurinae (Crocidura russula, Sunctes murinus). Our results indicate that sperm competition and metabolic rate may act independently or together reducing cycle length of spermatogenesis and thus increase sperm production. We finally investigated this correlation across 32 mammalian species. After testing the data for phylogenetic independence, our results showed that BMR explained only 21 % of the variation, while the RTS explained 44% of the variation of the cycle length of spermatogenesis. The level of the sperm competition, indicated by RTS, is thus to our knowledge the most important factor influencing the speed of spermatogenesis in mammals. RESUME : Les musaraignes sont parmi les plus anciens mammifères vivants. Grâce à leurs extrêmes divergences, ils sont souvent utilisés comme modèles dans des études comparatives. Les deux sous-familles Soricinae et Crocidurinae sont caractérisées par des différences fondamentales, notamment en termes d'intensité du métabolisme, des stratégies de reproduction et du comportement social. Dans la première partie de cette étude, nous avons établi et comparé certaines "caractéristiques des spermatozoïdes chez quatre espèces de musaraignes appartenant à des genres différents (Sorex araneus, Neomys fodiens, Crocidura russula et Suncus murinus). Les résultats ont été interprétés dans le contexte de la théorie de la compétition spermatique, c'est-à-dire la compétition entre le sperme de deux ou plusieurs mâles pour féconder un maximum d'ovules de la même femelle. Cette compétition spermatique peut amener à certaines adaptations biologiques afin de produire plus de sperme. Comme attendu, une grande taille relative des testicules est associée à un nombre élevé de spermatozoïdes, dont la majorité présente une mobilité progressive. Un taux élévé de testostérone a également été observé. De plus, nous avons étudié l'influence du métabolisme basal ainsi que l'intensité de la compétition spermatique sur la durée du cycle de la spermatogenèse. Dans ce but, nous avons déterminé et comparé les durées de la spermatogenèse chez six espèces de musaraignes appartenant à deux sous-familles : Soricinae (Sorex araneus, Sorex coronatus, Sorex minutus, Neomys fodiens) et Crocidurinae (Crocidura russula, Suncus murinus). Les résultats obtenus indiquent que ces deux facteurs (l'intensité du métabolisme basal et de la compétition spermatique) agissent d'une manière dépendante ou indépendante dans le même sens. La conséquence de ces actions est une diminution de la durée de la spermatogenèse entraînant une augmentation de la production de spermatozoïdes. Nous avons finalement étudié ce phénomène dans l'ensemble des mammifères. Après avoir testé l'indépendance phylogénétique, nos résultats montrent que l'intensité de la compétition spermatique indiquée par le RTS est mieux corrélée avec la régulation de la durée de la spermatogenèse qu'avec l'intensité du métabolisme.

Adolescent survivors of childhood cancer: are they vulnerable for psychological distress?

OBJECTIVES: We aimed to (i) evaluate psychological distress in adolescent survivors of childhood cancer and compare them to siblings and a norm population; (ii) compare the severity of distress of distressed survivors and siblings with that of psychotherapy patients; and (iii) determine risk factors for psychological distress in survivors. METHODS: We sent a questionnaire to all childhood cancer survivors aged <16 years when diagnosed, who had survived ≥ 5 years and were aged 16-19 years at the time of study. Our control groups were same-aged siblings, a norm population, and psychotherapy patients. Psychological distress was measured with the Brief Symptom Inventory-18 (BSI-18) assessing somatization, depression, anxiety, and a global severity index (GSI). Participants with a T-score ≥ 57 were defined as distressed. We used logistic regression to determine risk factors. RESULTS: We evaluated the BSI-18 in 407 survivors and 102 siblings. Fifty-two survivors (13%) and 11 siblings (11%) had scores above the distress threshold (T ≥ 57). Distressed survivors scored significantly higher in somatization (p=0.027) and GSI (p=0.016) than distressed siblings, and also scored higher in somatization (p ≤ 0.001) and anxiety (p=0.002) than psychotherapy patients. In the multivariable regression, psychological distress was associated with female sex, self-reported late effects, and low perceived parental support. CONCLUSIONS: The majority of survivors did not report psychological distress. However, the severity of distress of distressed survivors exceeded that of distressed siblings and psychotherapy patients. Systematic psychological follow-up can help to identify survivors at risk and support them during the challenging period of adolescence.

Maternal and paternal contributions to pathogen resistance dependent on development stage in a whitefish (Salmonidae)

It is often assumed that maternal and paternal contributions to offspring phenotype change over the lifetime of an individual. However, studies on parental effects typically suffer from the problems that heritabilities and maternal environmental effects are difficult to separate, and that both may depend on environmental factors and developmental stage. In order to experimentally disentangle maternal from paternal contributions and the likely effects of developmental stage from ecological effects, we sampled a natural population of the whitefish Coregonus palaea, used gametes for full-factorial in vitro fertilizations, raised over 10000 of the resulting offspring singly at controlled conditions, and exposed them at different points during embryonic development to one of two strains of Pseudomonas fluorescens that differed in their virulence characteristics (only one caused mortality, while both delayed hatching and reduced growth). Vulnerability to infection increased markedly over embryo development. This change coincided with a distinct shift in the importance of maternal to additive genetic effects on survival. Timing of exposure also affected the variance components for hatching time and larval length, but in a less consistent direction than the variance components for mortality. No significant genetic variation was found for any reaction norms across time points of exposure, indicating a uniformity among genotypes in how susceptibility changed over development. Phenotypes were also typically correlated across time points, which could constrain the evolution of the reaction norms. Our experiment demonstrates that the relative maternal and paternal contributions to susceptibility to an infection, and hence the evolutionary potential to respond to pathogen-induced selection, depends not only on the kind of pathogenic stress but also on the timing of the challenge.

Selective integration of auditory-visual looming cues by humans.

An object's motion relative to an observer can confer ethologically meaningful information. Approaching or looming stimuli can signal threats/collisions to be avoided or prey to be confronted, whereas receding stimuli can signal successful escape or failed pursuit. Using movement detection and subjective ratings, we investigated the multisensory integration of looming and receding auditory and visual information by humans. While prior research has demonstrated a perceptual bias for unisensory and more recently multisensory looming stimuli, none has investigated whether there is integration of looming signals between modalities. Our findings reveal selective integration of multisensory looming stimuli. Performance was significantly enhanced for looming stimuli over all other multisensory conditions. Contrasts with static multisensory conditions indicate that only multisensory looming stimuli resulted in facilitation beyond that induced by the sheer presence of auditory-visual stimuli. Controlling for variation in physical energy replicated the advantage for multisensory looming stimuli. Finally, only looming stimuli exhibited a negative linear relationship between enhancement indices for detection speed and for subjective ratings. Maximal detection speed was attained when motion perception was already robust under unisensory conditions. The preferential integration of multisensory looming stimuli highlights that complex ethologically salient stimuli likely require synergistic cooperation between existing principles of multisensory integration. A new conceptualization of the neurophysiologic mechanisms mediating real-world multisensory perceptions and action is therefore supported.

La formulation de cas : un modèle d'évaluation psychologique de l'enfant et de l'adolescent

L'article présente le modèle de la formulation de cas pour l'évaluation psychologique de l'enfant et de l'adolescent. La formulation de cas s'est développée en réponse au diagnostic psychiatrique qui peut être perc ̧u comme une approche réductionniste du fonctionnement psychique. En Europe, de nombreux psychologues cliniciens ont adopté ce modèle, qui a initialement été développé par les psychothérapeutes d'orientation cognitivo-comportementale, et l'ont adapté à leur pratique respective. Ce modèle, aujourd'hui bien ancré dans la pratique clinique quotidienne, consiste à élaborer différents regards théoriques intégrant les résultats de la recherche scientifique pour favoriser la compréhension d'un cas clinique. Ce modèle s'inscrit parallèlement dans une approche centrée sur les preuves et dans une pratique réflexive de la clinique. L'objectif de la formulation de cas est d'élaborer des hypothèses et de proposer des traitements adéquats. La famille est toutefois intégrée dans le processus de discussion et de prise de décision, ce qui permet de renforcer l'alliance thérapeutique. Cet article présente les trois courants théoriques les plus utilisés dans la formulation de cas : les approches cognitivo-comportementale, psychodynamique et systémique. L'utilisation d'une seule et même vignette permettra de montrer la pertinence du modèle et la complémentarité des différentes approches cliniques.

HIV infection disrupts the sympatric host-pathogen relationship in human tuberculosis.

The phylogeographic population structure of Mycobacterium tuberculosis suggests local adaptation to sympatric human populations. We hypothesized that HIV infection, which induces immunodeficiency, will alter the sympatric relationship between M. tuberculosis and its human host. To test this hypothesis, we performed a nine-year nation-wide molecular-epidemiological study of HIV-infected and HIV-negative patients with tuberculosis (TB) between 2000 and 2008 in Switzerland. We analyzed 518 TB patients of whom 112 (21.6%) were HIV-infected and 233 (45.0%) were born in Europe. We found that among European-born TB patients, recent transmission was more likely to occur in sympatric compared to allopatric host-pathogen combinations (adjusted odds ratio [OR] 7.5, 95% confidence interval [95% CI] 1.21-infinity, p = 0.03). HIV infection was significantly associated with TB caused by an allopatric (as opposed to sympatric) M. tuberculosis lineage (OR 7.0, 95% CI 2.5-19.1, p<0.0001). This association remained when adjusting for frequent travelling, contact with foreigners, age, sex, and country of birth (adjusted OR 5.6, 95% CI 1.5-20.8, p = 0.01). Moreover, it became stronger with greater immunosuppression as defined by CD4 T-cell depletion and was not the result of increased social mixing in HIV-infected patients. Our observation was replicated in a second independent panel of 440 M. tuberculosis strains collected during a population-based study in the Canton of Bern between 1991 and 2011. In summary, these findings support a model for TB in which the stable relationship between the human host and its locally adapted M. tuberculosis is disrupted by HIV infection.

Insulin-like growth factor-I and C-reactive protein during pregnancy and maternal risk of non-epithelial ovarian cancer: a nested case-control study.

BACKGROUND: Insulin-like growth factor-I (IGF-I) and C-reactive protein (CRP) may be positively associated with the risk of epithelial ovarian cancer (EOC) but no previous studies have investigated their associations with non-epithelial ovarian cancers (NEOC). METHODS: A case-control study was nested within the Finnish Maternity Cohort. Case subjects were 58 women diagnosed with sex cord-stromal tumors (SCST) and 30 with germ cell tumors (GCT) after recruitment. Control subjects (144 for SCST and 74 for GCT) were matched for age, parity, and date of blood donation of the index case. RESULTS: Doubling of IGF-I concentration was not related to maternal risk of either SCST (OR 0.97, 95% CI 0.58-1.62) or GCT (OR 1.13, 95% CI 0.51-2.51). Similarly, doubling of CRP concentrations was not related to maternal risk of either SCST (OR 1.10, 95% CI 0.85-1.43) or GCT (OR 0.93, 95% CI 0.68-1.28). CONCLUSIONS: Pre-diagnostic IGF-I and CRP concentrations during the first trimester of pregnancy were not associated with increased risk of NEOC in the mother. Risk factors for NEOC may differ from those of EOC.

The adolescent with a chronic condition. Part I: developmental issues.

The prevalence of chronic conditions among adolescents is difficult to assess due to the lack of quality data focusing specifically on this age group, as well as the diversity in methodology and definitions used. However, surveys carried out by self administered questionnaires among in-school adolescent populations indicate that around 10% of adolescents suffer from such a condition. The aim of this paper is to analyse the reciprocal effects of chronic conditions and adolescent development by reviewing the effect of chronic disease on growth and puberty and on psychosocial development, and the effect of developmental issues on the course and management of chronic disease.

Relationship between dopamine D2 receptor occupancy, clinical response, and drug and monoamine metabolites levels in plasma and cerebrospinal fluid. A pilot study in patients suffering from first-episode schizophrenia treated with quetiapine.

Combining measurements of the monoamine metabolites in the cerebrospinal fluid (CSF) and neuroimaging can increase efficiency of drug discovery for treatment of brain disorders. To address this question, we examined five drug-naïve patients suffering from schizophrenic disorder. Patients were assessed clinically, using the Positive and Negative Syndrome Scale (PANSS): at baseline and then at weekly intervals. Plasma and CSF levels of quetiapine and norquetiapine as well CSF 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxyindole-acetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were obtained at baseline and again after at least a 4 week medication trail with 600 mg/day quetiapine. CSF monoamine metabolites levels were compared with dopamine D(2) receptor occupancy (DA-D(2)) using [(18)F]fallypride and positron emission tomography (PET). Quetiapine produced preferential occupancy of parietal cortex vs. putamenal DA-D(2), 41.4% (p<0.05, corrected for multiple comparisons). DA-D(2) receptor occupancies in the occipital and parietal cortex were correlated with CSF quetiapine and norquetiapine levels (p<0.01 and p<0.05, respectively). CSF monoamine metabolites were significantly increased after treatment and correlated with regional receptor occupancies in the putamen [DOPAC: (p<0.01) and HVA: (p<0.05)], caudate nucleus [HVA: (p<0.01)], thalamus [MHPG: (p<0.05)] and in the temporal cortex [HVA: (p<0.05) and 5-HIAA: (p<0.05)]. This suggests that CSF monoamine metabolites levels reflect the effects of quetiapine treatment on neurotransmitters in vivo and indicates that monitoring plasma and CSF quetiapine and norquetiapine levels may be of clinical relevance.

Controversies about the enhanced vulnerability of the adolescent brain to develop addiction.

Adolescence, defined as a transition phase toward autonomy and independence, is a natural time of learning and adjustment, particularly in the setting of long-term goals and personal aspirations. It also is a period of heightened sensation seeking, including risk taking and reckless behaviors, which is a major cause of morbidity and mortality among teenagers. Recent observations suggest that a relative immaturity in frontal cortical neural systems may underlie the adolescent propensity for uninhibited risk taking and hazardous behaviors. However, converging preclinical and clinical studies do not support a simple model of frontal cortical immaturity, and there is substantial evidence that adolescents engage in dangerous activities, including drug abuse, despite knowing and understanding the risks involved. Therefore, a current consensus considers that much brain development during adolescence occurs in brain regions and systems that are critically involved in the perception and evaluation of risk and reward, leading to important changes in social and affective processing. Hence, rather than naive, immature and vulnerable, the adolescent brain, particularly the prefrontal cortex, should be considered as prewired for expecting novel experiences. In this perspective, thrill seeking may not represent a danger but rather a window of opportunities permitting the development of cognitive control through multiple experiences. However, if the maturation of brain systems implicated in self-regulation is contextually dependent, it is important to understand which experiences matter most. In particular, it is essential to unveil the underpinning mechanisms by which recurrent adverse episodes of stress or unrestricted access to drugs can shape the adolescent brain and potentially trigger life-long maladaptive responses.

Mirror image atrial dilatation in adult patients with atrial fibrillation and congenital heart disease.

BACKGROUND: Atrial fibrillation (AF) is largely regarded to be initiated from left atrial (LA) dilatation, with subsequent dilatation of the right atrium (RA) in those who progress to chronic AF. We hypothesized that in adult patients with right-sided congenital heart disease (CHD) and AF, RA dilatation will predominate with subsequent dilatation of the left atrium, as a mirror image. METHODS: Adult patients with diagnosis of right-sided, ASD or left-sided CHD who had undergone an echocardiographic study and electrocardiographic recording in 2007 were included. RA and LA area were measured from the apical view. AF was diagnosed from a 12-lead electrocardiogram or Holter recording. A multivariate logistic regression model was used to identify predictors of AF and linear regression models were performed to measure relationship between RA and LA area and AF. RESULTS: A total of 291 patients were included in the study. Multivariate analysis showed that age (p=0.0001), RA (p=0.025) and LA area (p=0.0016) were significantly related to AF. In patients with pure left-sided pathologies, there was progressive and predominant LA dilatation that paralleled the development of AF from none to paroxysmal to chronic AF. In patients with pure right-sided pathologies, there was a mirror image of progressive and predominant RA dilatation with the development of AF. CONCLUSION: We observed a mirror image atrial dilatation in patients with right sided disease and AF. This may provide novel mechanistic insight as to the origin of AF in these patients and deserves further studying in the form of targeted electrophysiological studies.

Normal weight obesity: relationship with lipids, glycaemic status, liver enzymes and inflammation

BACKGROUND AND AIMS: Normal weight obesity (NWO) is defined as an excessive body fat associated with a normal body mass index (BMI) and has been associated with early inflammation, but its relationship with cardiovascular risk factors await investigation. METHODS AND RESULTS: Cross-sectional study including 3213 women and 2912 men aged 35-75 years to assess the clinical characteristics of NWO in Lausanne, Switzerland. Body fat was assessed by bioimpedance. NWO was defined as a BMI<25 kg/m(2) and a % body fat ≥66(th) gender-specific percentiles. The prevalence of NWO was 5.4% in women and less than 3% in men, so the analysis was restricted to women. NWO women had a higher % of body fat than overweight women. After adjusting for age, smoking, educational level, physical activity and alcohol consumption, NWO women had higher blood pressure and lipid levels and a higher prevalence of dyslipidaemia (odds-ratio=1.90 [1.34-2.68]) and fasting hyperglycaemia (odds-ratio=1.63 [1.10-2.42]) than lean women, whereas no differences were found between NWO and overweight women. Conversely, no differences were found between NWO and lean women regarding levels of CRP, adiponectin and liver markers (alanine aminotransferase, aspartate aminotransferase and gamma glutamyl transferase). Using other definitions of NWO led to similar conclusions, albeit some differences were no longer significant. CONCLUSION: NWO is almost nonexistent in men. Women with NWO present with higher cardiovascular risk factors than lean women, while no differences were found for liver or inflammatory markers. Specific screening of NWO might be necessary in order to implement cardiovascular prevention.

The Relationship between Media and Political Agendas : Variations across Decision-Making Phases

Previous studies have demonstrated that the extent to which media coverage influences the issue priorities of policy makers is contingent on the type of issue, media, and political agenda. This article contends that the relationship between media and political agendas varies across the phases of the decision-making process. Based on a comprehensive dataset on issue attention in media coverage and various policy-making channels covering the years 1996-2003, the article analyses the level of media coverage and, more importantly, the distribution and correspondence of issue attention between media and political agendas across the four successive phases of the decision-making process (initiation, preparatory, parliamentary, and referendum phases) in Switzerland. Despite inversely distributed levels of attention for successive decision-making phases, both media and political agendas are concentrated on fewer issues in the initiation and referendum phases, and they are more strongly correlated in the most decisive stages of the process, that is, the preparatory and referendum phases.