Relations of the job demands-control-support model of job strain with personality attributes : a cross-cultural study in Switzerland and South Africa

Among the various work stress models, one of the most popular to date is the job demands-­‐control (JDC) model developed by Karasek (1979), which postulates that work-­‐related strain will be the highest under work conditions characterized by high demands and low autonomy. The absence of social support at work will further increase negative outcomes. However, this model does not apply equally to all individuals and to all cultures. In the following studies, we assessed work characteristics, personality traits, culture-­‐driven individual attributes, and work-­‐related health outcomes, through the administration of questionnaires. The samples consist of Swiss (n = 622) and South African (n = 879) service-­‐oriented employees (from health, finance, education and commerce sectors) and aged from 18 to 65 years old. Results generally confirm the universal contribution of high psychological demands, low decision latitude and low supervisor support at work, as well as high neuroticism predict the worse health outcomes among employees in both countries. Furthermore, low neuroticism plays a moderating role between psychological demands and burnout, while high openness and high conscientiousness each play a moderating role between decision latitude and burnout in South Africa. Results also reveal that culture-­‐driven individual attributes play a role in both countries, but in a unique manner and according to the ethnic group of belonging. Given that organizations are increasingly characterized with multicultural employees as well as increasingly adverse and complex job conditions, our results help in identifying more updated and refined dynamics that are key between the employee and the work environment in today's context. -- L'un des modèles sur le stress au travail des plus répandus est celui développé par Karasek (1979), qui postule qu'une mauvaise santé chez les employés résulte d'une combinaison de demandes psychologiques élevées, d'une latitude décisionnelle faible et de l'absence de soutien social au travail. Néanmoins, ce modèle ne s'applique pas de façon équivalente chez tous les individus et dans toutes les cultures. Dans les études présentées, nous avons mesuré les caractéristiques de travail, les traits de personnalité, les traits culturels et les effets lies à la santé à l'aide de questionnaires. L'échantillon provient de la Suisse (n = 622) et de l'Afrique du Sud (n = 879) et comprend des employés de domaines divers en lien avec le service (notamment des secteurs de la santé, finance, éducation et commerce) tous âgés entre 18 et 65 ans. Les résultats confirment l'universalité des effets directs des demandes au travail, la latitude décisionnelle faible, le soutien social faible provenant du supérieur hiérarchique, ainsi que le névrosisme élevé qui contribuent à un niveau de santé faible au travail, et ce, dans les deux pays. De plus, un niveau faible de névrosisme a un effet de modération entre les demandes au travail et l'épuisement professionnel, alors que l'ouverture élevée et le caractère consciencieux élevé modèrent la relation entre la latitude décisionnelle et l'épuisement professionnel en Afrique du Sud. Nous avons aussi trouvé que les traits culturels jouent un rôle dans les deux pays, mais de façon unique et en fonction du groupe ethnique d'appartenance. Sachant que les organisations sont de plus en plus caractérisées par des employés d'origine ethnique variées, et que les conditions de travail se complexifient, nos résultats contribuent à mieux comprendre les dynamiques entre l'employé et l'environnement de travail contemporain. personnalité, différences individuelles, comparaisons culturelles, culture, stress au travail, épuisement professionnel, santé des employés.

Is the coiled body involved in nucleolar functions?

Coiled bodies (CBs) are structural constituents observed in nuclei of most eukaryotic cells. They usually occur in the nucleoplasm as well as in contact with the nucleolar surface. In this work we studied the hepatocyte nuclei of hibernating dormice in order to investigate possible modifications of CBs along the seasonal cycle. CBs were abundant during hibernation and rapidly disappeared upon arousal from hibernation. Moreover, CBs were frequently found to be integrated into the nucleolar body. Immunocytochemical analyses showed that CBs contain nucleoplasmic as well as nucleolar RNA-processing factors, suggesting an "ambiguous" role for this organelle in the nuclear functions.

Separate neuronal and glial Na+,K+-ATPase isoforms regulate glucose utilization in response to membrane depolarization and elevated extracellular potassium.

The role of cell type-specific Na+,K+-ATPase isozymes in function-related glucose metabolism was studied using differentiated rat brain cell aggregate cultures. In mixed neuron-glia cultures, glucose utilization, determined by measuring the rate of radiolabeled 2-deoxyglucose accumulation, was markedly stimulated by the voltage-dependent sodium channel agonist veratridine (0.75 micromol/L), as well as by glutamate (100 micromol/L) and the ionotropic glutamate receptor agonist N-methyl-D-aspartate (NMDA) (10 micromol/L). Significant stimulation also was elicited by elevated extracellular potassium (12 mmol/L KCl), which was even more pronounced at 30 mmol/L KCl. In neuron-enriched cultures, a similar stimulation of glucose utilization was obtained with veratridine, specific ionotropic glutamate receptor agonists, and 30 mmol/L but not 12 mmol/L KCl. The effects of veratridine, glutamate, and NMDA were blocked by specific antagonists (tetrodotoxin, CNQX, or MK801, respectively). Low concentrations of ouabain (10(-6) mol/L) prevented stimulation by the depolarizing agents but reduced only partially the response to 12 mmol/L KCl. Together with previous data showing cell type-specific expression of Na+,K+-ATPase subunit isoforms in these cultures, the current results support the view that distinct isoforms of Na+,K+-ATPase regulate glucose utilization in neurons in response to membrane depolarization, and in glial cells in response to elevated extracellular potassium.

Macrophages induce neutrophil apoptosis through membrane TNF, a process amplified by Leishmania major.

Neutrophils are recruited to the site of parasite inoculation within a few hours of infection with the protozoan parasite Leishmania major. In C57BL/6 mice, which are resistant to infection, neutrophils are cleared from the site of s.c. infection within 3 days, whereas they persist for at least 10 days in susceptible BALB/c mice. In the present study, we investigated the role of macrophages (MPhi) in regulating neutrophil number. Inflammatory cells were recruited by i.p. injection of either 2% starch or L. major promastigotes. Neutrophils were isolated and cultured in the presence of increasing numbers of MPhi. Extent of neutrophil apoptosis positively correlated with the number of MPhi added. This process was strictly dependent on TNF because MPhi from TNF-deficient mice failed to induce neutrophil apoptosis. Assays using MPhi derived from membrane TNF knock-in mice or cultures in Transwell chambers revealed that contact with MPhi was necessary to induce neutrophil apoptosis, a process requiring expression of membrane TNF. L. major was shown to exacerbate MPhi-induced apoptosis of neutrophils, but BALB/c MPhi were not as potent as C57BL/6 MPhi in this induction. Our results emphasize the importance of MPhi-induced neutrophil apoptosis, and membrane TNF in the early control of inflammation.

Cytological Findings Suggesting Sexuality in Phytomonas davidi (Protozoa: Kinetoplastida)

On few occasions, Phytomonas davidi (McGhee & Postell isolate) cultures in LIT (liver infusion-tryptose) medium around 27oC presented, as seen in Giemsa-stained smears, a set of peculiar morphological features, among them being noticeable the pairs of apposed cells attached by their posterior ends, where occurred a stained line and/or a dilatation, usually bulb-like in shape; sometimes this dilatation could occupy one of the cells or hold both together. In some pairs, the nucleus of each parasite seemed migrating towards the other, entering into such dilatation; in others, both nuclei were inside it, sometimes in close proximity or seeming fused; peculiar chromatin arrangements involving both nuclei were occasionally observed. Several mono or binucleate round forms bearing one or two flagella, as well as flagellate slender cells without nucleus were concomitantly seen there. In some instances, an intriguing small stained body occurred beside a single large nucleus, either in pairs presenting the bulb-like structure or in round cells. These cytological findings seemed steps of a dynamic process suggesting sexuality, since in several of them nuclear interactions following fusion of two parasites appeared to occur

Facing the challenge: The impact of the recession and unemployment on men's health in Ireland

The economic recession with its accompanying rise in unemployment rates is linked to extremely adverse effects for men’s mental health. This research report Facing the Challenge – The Impact of the Recession and Unemployment on Men’s Health in Ireland identifies a strong expectation of increased mental health problems for men given the very strong correlation between unemployment and male mental ill health. The report is the result of a research and consultation process carried out, in Northern Ireland and the Republic of Ireland, by Nexus Research Co-operative on behalf of IPH. 93% of frontline organisations, North and South, in contact with unemployed men linked health challenges to unemployment and recession and all organisations surveyed noted adverse health challenges for men they work with. In addition to health challenges being higher for unemployed men, they were also very high for men who saw themselves as being threatened with unemployment. The organisations surveyed and the men who were interviewed identified the challenges to health as:•    High levels of stress or anxiety•    Dependency on or over-use of alcohol/other drugs•    Deterioration in physical health•    Development of conflict in family or close personal relationships•    Isolation (including sharing or communicating problems)•    A reluctance to approach services or seek help

Síntesi de siRNAs (short interfering RNAs) modificats amb nucleobases 5-metil i 5-propinil pirimidíniques i avaluació de la seva activitat in vitro en cultius cel•lulars i de la seva estabilitat en sèrum humà. Disseny de siRNAs dirigits a la inhibició de l'expressió de mutacions de l'oncogen K-ras.

Projecte de recerca elaborat a partir d’una estada a la Stanford University, EEUU, entre 2007 i 2009. El present projecte es basa 1) en la síntesi de cadenes d'ARN dirigides a la inhibició de l'expressió gènica per un mecanisme d'ARN d'interferència (siRNAs o short interefering RNAs) i 2) en l'avaluació de l'activitat in vitro d'aquests oligonucleòtids en cultius cel•lulars. Concretament, la meva recerca ha estat enfocada principalment a l'estudi de cadenes de siRNA modificades amb nucleobases 5-metil i 5-propinil pirimidíniques. Es tractava d'avaluar l'efecte que exerceixen els factors estèrics en el major groove (solc major) dels siRNAs sobre la seva activitat biològica. En aquest sentit, he dut aterme síntesi de fosforamidits de nucleòsis pirimidínics modificats a la posició C-5 de la nucleobase. A continuació he incorporat aquestes unitats nucleosídiques en cadenes d'ARN emprant un sintetitzador d’ADN/ARN i he estudiat l'estabilitat dels corresponents dúplexs d'ARN mitjançant experiments de desnaturalització tèrmica. Finalment he dut a terme experiments d'inhibició de l'expressió gènica en cèl.lules HeLa per tal d'avaluar l'activitat biològia d'aquests siRNAs modificats. Els resultats d'aquests estudis han posat de manifest que la presència de grups voluminosos com el propinil a l'extrem 5' del dúplex de siRNA (definit per la cadena guia o antisense) influeix de forma molt negativa en la seva activitat biològica. En canvi, grups menys voluminosos com el metil hi influeixen positivament, de manera que algunes de les cadenes sintetitzades han resultat ser més actives que els corresponents siRNAs naturals (wild type siRNAs). A més, aquest tipus de modificació contribueix positivament en l'estabilitat de cadenes de siRNA en sèrum humà. Aquest treball ha estat publicat (Terrazas, M.; Kool, E.T. "Major Groove Modifications Improve siRNA Stability and Biological Activity" Nucleic Acids Res. 2009, in press).

Triatoma infestans in Greater Buenos Aires, Argentina

The Health Administration Agencies of many municipalities in Greater Buenos Aires (GBA) receive frequent reports on triatomines in houses. The aim of this work was to identify and describe the dispersal foci of Triatoma infestans in an urban neighborhood of GBA, and contribute to the knowledge of the epidemiological situation in the region. In June 1998, potentially infested places were entomologically evaluated. T. infestans was only detected in a hen building for egg production, which housed approximately 6,000 birds. A total of 2,930 insects were collected. Density was about 9 triatomines/m². The proportions of fifth instar nymphs and adults were significantly higher than those of the other stages (p<0.001). The number of triatomines collected largely exceeded the highest domestic infestation found in one house from rural endemic areas of Argentina. Though triatomines were negative for Trypanosoma cruzi, they could acquire the parasite by coming in contact with infected people living in GBA. Besides, the numerous and widely distributed places housing hens and chickens, would favor the settlement of the vector. Together, both facts may constitute a risk of parasitic vectorial transmission. It is recommended to intensify systematic activities of vector search and case detection in GBA.

The origin and dispersion of human parasitic diseases in the Old World (Africa, Europe and Madagascar)

The ancestors of present-day man (Homo sapiens sapiens) appeared in East Africa some three and a half million years ago (Australopithecs), and then migrated to Europe, Asia, and later to the Americas, thus beginning the differentiation process. The passage from nomadic to sedentary life took place in the Middle East in around 8000 BC. Wars, spontaneous migrations and forced migrations (slave trade) led to enormous mixtures of populations in Europe and Africa and favoured the spread of numerous parasitic diseases with specific strains according to geographic area. The three human plasmodia (Plasmodium falciparum, P. vivax, and P. malariae) were imported from Africa into the Mediterranean region with the first human migrations, but it was the Neolithic revolution (sedentarisation, irrigation, population increase) which brought about actual foci for malaria. The reservoir for Leishmania infantum and L. donovani - the dog - has been domesticated for thousands of years. Wild rodents as reservoirs of L. major have also long been in contact with man and probably were imported from tropical Africa across the Sahara. L. tropica, by contrast, followed the migrations of man, its only reservoir. L. infantum and L. donovani spread with man and his dogs from West Africa. Likewise, for thousands of years, the dog has played an important role in the spread and the endemic character of hydatidosis through sheep (in Europe and North Africa) and dromadary (in the Sahara and North Africa). Schistosoma haematobium and S. mansoni have existed since prehistoric times in populations living in or passing through the Sahara. These populations then transported them to countries of Northern Africa where the specific, intermediary hosts were already present. Madagascar was inhabited by populations of Indonesian origin who imported lymphatic filariosis across the Indian Ocean (possibly of African origin since the Indonesian sailors had spent time on the African coast before reaching Madagascar). Migrants coming from Africa and Arabia brought with them the two African forms of bilharziosis: S. haematobium and S. mansoni.

Species differences in the response of liver drug-metabolizing enzymes to (S)-4-O-tolylsulfanyl-2-(4-trifluormethyl-phenoxy)-butyric acid (EMD 392949) in vivo and in vitro.

Induction of drug-metabolizing enzymes (DMEs) is highly species-specific and can lead to drug-drug interaction and toxicities. In this series of studies we tested the species specificity of the antidiabetic drug development candidate and mixed peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist (S)-4-O-tolylsulfanyl-2-(4-trifluormethyl-phenoxy)-butyric acid (EMD 392949, EMD) with regard to the induction of gene expression and activities of DMEs, their regulators, and typical PPAR target genes. EMD clearly induced PPARalpha target genes in rats in vivo and in rat hepatocytes but lacked significant induction of DMEs, except for cytochrome P450 (P450) 4A. CYP2C and CYP3A were consistently induced in livers of EMD-treated monkeys. Interestingly, classic rodent peroxisomal proliferation markers were induced in monkeys after 17 weeks but not after a 4-week treatment, a fact also observed in human hepatocytes after 72 h but not 24 h of EMD treatment. In human hepatocyte cultures, EMD showed similar gene expression profiles and induction of P450 activities as in monkeys, indicating that the monkey is predictive for human P450 induction by EMD. In addition, EMD induced a similar gene expression pattern as the PPARalpha agonist fenofibrate in primary rat and human hepatocyte cultures. In conclusion, these data showed an excellent correlation of in vivo data on DME gene expression and activity levels with results generated in hepatocyte monolayer cultures, enabling a solid estimation of human P450 induction. This study also clearly highlighted major differences between primates and rodents in the regulation of major inducible P450s, with evidence of CYP3A and CYP2C inducibility by PPARalpha agonists in monkeys and humans.

Differential tissue tropism of Trypanosoma cruzi strains: an in vitro study

We have previously demonstrated selection favoring the JG strain of Trypanosoma cruziin hearts of BALB/c mice that were chronically infected with an equal mixture of the monoclonal JG strain and a clone of the Colombian strain, Col1.7G2. To evaluate whether cell invasion efficiency drives this selection, we infected primary cultures of BALB/c cardiomyocytes using these same T. cruzi populations. Contrary to expectation, Col1.7G2 parasites invaded heart cell cultures in higher numbers than JG parasites; however, intracellular multiplication of JG parasites was more efficient than that of Col1.7G2 parasites. This phenomenon was only observed for cardiomyocytes and not for cultured Vero cells. Double infections (Col1.7G2 + JG) showed similar results. Even though invasion might influence tissue selection, our data strongly suggest that intracellular development is important to determine parasite tissue tropism.

Efficiency diagnostic and advantages of procalcitonin and C-reactive protein in the early diagnosis of sepsis.

The goal of our study is to assess the diagnostic profi tability of procalcitonin (PCT) in septic shock and another biomarker as C-reactive protein (CRP). Results: Fifty-four septic patients were assessed, 66% were males; mean age, 63 years. Eighty-eight percent was diagnosed as septic shock and 11% severe sepsis. Seventy-six percent were medical patients. Positive blood cultures in 42.5%. Sepsis origin: respiratory 46%, neurological 5%, digestive 37% and urinary 3%. Average SOFA score was 10.4. Conclusions: PCT and CRP have the same efficiency in early sepsis diagnosis. The PCT and CRP effi ciency diagnostic together is signifi cant but small. We suggest using both with the doubt of sepsis.

Fièvre, adénopathie: une situation clinique de toxoplasmose aiguë chez une patiente immunocompétente [Fever and lymphadenopathy: acute toxoplasmosis in an immunocompetent patient].

Toxoplasmosis is an infectious disease caused by the intracellular parasite Toxoplasma gondii. In Switzerland about a third of the population has antibodies against this pathogen and has thus already been in contact with the parasite or has contracted the disease. Immunocompetent patients are usually asymptomatic (80-90%) during primary infection. The most common symptom is neck or occipital lymphadenopathy. Serology is the diagnostic gold standard in immunocompetent individuals. The presence of IgM antibodies is however not sufficient to make a definite diagnosis of acute toxoplasmosis. Distinction between acute and chronic toxoplasmosis requires additional serological tests (IgG avidity test). If required, the most used and probably most effective treatment is the combination of pyrimethamine and sulfadiazine, with folinic acid.

Personality disorders and the Five-Factor Model among French speakers in Africa and Europe

Objective: Several authors have suggested that Personality Disorders (PDs) might be more accurately described using a dimensional model instead of a categorical one. The aim of this study was to describe the relationship between PDs and the Five-Factor Model (FFM)-a dimensional model describing normal personality traits known for its invariance across cultures-in two different cultural settings. Method: Subjects from nine French-speaking African countries (n = 2,014) and from Switzerland (n = 697) completed both the French-version of the IPDE screening questionnaire, assessing the ten DSM-IV PDs, and the French-version of the NEO-PI-R, assessing the five domains and thirty facets of the FFM. Results: Correlations between PDs and the five domains of the FFM were similar in both samples. For example, Neuroticism was highly correlated with Borderline, Avoidant, and Dependent PDs in both Africa and Switzerland. The total rank-order correlation (rho) between the two correlation matrices was very high (rho = 0.93) and significant (P < 0.001), as were the rhos for all domains of the FFM and all PDs, except Paranoid and Dependent PDs. However, the rhos for PDs across facet-scales were all highly significant (P < 0.001). Moreover, 80% of Widiger and colleagues' predictions and 70 % of Lynam and Widiger's prototypes, concerning the relationship between PDs and the FFM, were confirmed in both samples. Conclusions: The relationship between PDs and the FFM was stable in two samples separated by a great cultural distance. These results suggest that a dimensional approach and in particular the FFM might be useful for describing PDs in a variety of cultural settings.

The behaviour of mosquitoes in relation to humans under holed bednets: the evidence from experimental huts

The physical integrity of bednets is a concern of national malaria control programs, as it is a key factor in determining the rate of replacement of bednets. It is largely assumed that increased numbers of holes will result in a loss of protection of sleepers from potentially infective bites. Experimental hut studies are valuable in understanding mosquito behaviour indoors, particularly as it relates to blood feeding and mortality. This review summarises findings from experimental hut studies, focusing on two issues: (i) the effect of different numbers or sizes of holes in bednets and (ii) feeding behaviour and mortality with holed nets as compared with unholed nets. As might be expected, increasing numbers and area of holes resulted in increased blood feeding by mosquitoes on sleepers. However, the presence of holes did not generally have a large effect on the mortality of mosquitoes. Successfully entering a holed mosquito net does not necessarily mean that mosquitoes spend less time in contact with the net, which could explain the lack in differences in mortality. Further behavioural studies are necessary to understand mosquito behaviour around nets and the importance of holed nets on malaria transmission.