Working on Sundays–effects on safety, health, and work-life balance

Several attributes of the work schedule can increase the risk of occupational injuries and accidents, health impairments, and reduced social participation. Although previous studies mainly focused on the effects of shiftwork and long working hours on employee health and safety, there is little evidence of a potential negative impact of working Sundays on the incidence of occupational accidents, health impairments, and work-life balance. A representative sample of employed workers in 31 member and associated states of the European Union (n?=?23,934) served as the database for a cross-sectional analysis. The sample was collected via face-to-face interviews in the year 2005. The association of the risks of occupational accidents, health impairments, and decreases in work-life balance with working Sundays was calculated using logistic regression models, controlling for potential confounders, such as shiftwork, workload, and demographic characteristics. The results indicated that working one or more Sundays/month was associated with increase both in the risk of reporting one or more health impairments (odds ratio [OR]: 1.17, 95% confidence interval [CI]: 1.06-1.29) and poorer work-life balance (OR: 1.15, 95% CI: 1.02-1.28). These effects remained after controlling for potentially confounding factors, such as other work schedule attributes, intensity of physical and mental workload, and individual characteristics. Furthermore, working Sundays was also related to increased risk of occupational accidents within the last year (OR: 1.34, 95% CI: 1.03-1.73). Controlling again for individual, workload, and working-time characteristics, a significant association with accident risk, however, remained only in work sectors with low a priori risk of occupational accidents (OR: 1.40, 95% CI: 1.02-1.91), although the increased risk could be observed for both medium and high a priori risk sectors working Sundays (without controlling for additional confounders). The results thus indicate that the detrimental effects of working Sundays on safety, health, and social well-being should be taken into account when designing work schedules. The potential hazards to employees' safety, health, and work-life balance, in particular, should be considered in discussions concerning extending work on Sundays in certain sectors, e.g., retail.     

Working on Sundays–Effects on Safety,Health, and Work-life Balance

Several attributes of the work schedule can increase the risk of occupational injuries and accidents, health impairments, and reduced social participation. Although previous studies mainly focused on the effects of shiftwork and long working hours on employee health and safety, there is little evidence of a potential negative impact of working Sundays on the incidence of occupational accidents, health impairments, and work-life balance. A representative sample of employed workers in 31 member and associated states of the European Union (n?=?23,934) served as the database for a cross-sectional analysis. The sample was collected via face-to-face interviews in the year 2005. The association of the risks of occupational accidents, health impairments, and decreases in work-life balance with working Sundays was calculated using logistic regression models, controlling for potential confounders, such as shiftwork, workload, and demographic characteristics. The results indicated that working one or more Sundays/month was associated with increase both in the risk of reporting one or more health impairments (odds ratio [OR]: 1.17, 95% confidence interval [CI]: 1.06–1.29) and poorer work-life balance (OR: 1.15, 95% CI: 1.02–1.28). These effects remained after controlling for potentially confounding factors, such as other work schedule attributes, intensity of physical and mental workload, and individual characteristics. Furthermore, working Sundays was also related to increased risk of occupational accidents within the last year (OR: 1.34, 95% CI: 1.03–1.73). Controlling again for individual, workload, and working-time characteristics, a significant association with accident risk, however, remained only in work sectors with low a priori risk of occupational accidents (OR: 1.40, 95% CI: 1.02–1.91), although the increased risk could be observed for both medium and high a priori risk sectors working Sundays (without controlling for additional confounders). The results thus indicate that the detrimental effects of working Sundays on safety, health, and social well-being should be taken into account when designing work schedules. The potential hazards to employees' safety, health, and work-life balance, in particular, should be considered in discussions concerning extending work on Sundays in certain sectors, e.g., retail. (Author correspondence: awirtz@hsph.harvard.edu)     

Motility, Potentiality, and Infinity—A Semiotic Hypothesis on Nature and Religion

Against any obscurantist stand, denying the interest of natural sciences for the comprehension of human meaning and language, but also against any reductionist hypothesis, frustrating the specificity of the semiotic point of view on nature, the paper argues that the deepest dynamic at the basis of meaning consists in its being a mechanism of ??potentiality navigation?? within a universe generally characterized by motility. On the one hand, such a hypothesis widens the sphere of meaning to all beings somehow endowed with the capacity of moving and/or perceiving movement. On the other hand, through a new evolutionist interpretation of the concept of generativity, such a hypothesis preserves the peculiarity of human meaning, meant as essentially founded on a certain intuition of infinity. Two corollaries stem from this hypothesis: first, religiosity can be considered as a matrix of grammars of infinity, aiming at regimenting its flight of potentialities. Second, non-genetic transmission of cultural information exerts determinant influence also at the level of that very deep mechanism of the human predicament that is the cognitive navigation of motor potentialities. A re-reading of the structuralist epistemology, scientific literature on the nervous cells of jellyfish, and some recent experiments on the mirror neurons of dancers, as well as certain intuitions of Teilhard de Chardin, are the main arguments of the paper.     

Biological activities of the LXRα and β agonist, 4β-hydroxycholesterol,and of its isomer, 4α-hydroxycholesterol,on oligodendrocytes: Effects on cell growth and viability,oxidative and inflammatory status

The biochemical and biological properties of 4β-hydroxycholesterol and of its isomer, 4α-hydroxycholesterol, are not well known. So, we determined the ability of 4α- and 4β-hydroxycholesterol to react with LXRα and LXRβ, and we characterized the activities of these oxysterols on oligodendrocytes which are myelin synthesizing cells. The effects of 4α- and 4β-hydroxycholesterol were studied on 158N murine oligodendrocytes to assess their activities on cell growth and viability, oxidative and inflammatory status. To this end different parameters were used: cell counting with trypan blue; identification of dead cells and cell cycle analysis with propidium iodide; evaluation of mitochondrial depolarization, lysosomal membrane integrity, actin depolimerization, nuclear morphology, and superoxide anion production after staining with JC-1, acridine orange, rhodamine-phalloidin, Hoechst 33342, and dihydroethidium, respectively; evaluation of ultrastructural changes by transmission electron microscopy, and cytokine quantification with a cytometric bead array. Only 4β-hydroxycholesterol is a LXRα and β agonist. No cytotoxic effects were found with 4α-hydroxycholesterol except a slight inhibition of cell growth at elevated concentrations. At high concentrations, 4β-hydroxycholesterol was not only able to inhibit cell growth, but also to induce cell death associated with a loss of mitochondrial transmembrane potential, dysfunctions of lysosomal membrane integrity, and superoxide anion overproduction. These side effects were lower than those observed with 7-ketocholesterol and 25-hydroxycholesterol used as positive controls. On oligodendrocyte murine primary cultures, only lysosomal membrane integrity was slightly affected under treatment with 4α- and 4β-hydroxycholesterol. So, 4α- and 4β-hydroxycholesterol have different biological activities. Their ability to induce cytotoxic effects on oligodendrocytes can be considered as weak comparatively to 7-ketocholesterol and 25-hydroxycholesterol.     

A special issue on ＂Interferons, Cytokines, and Immunity＂

Vertebrates including human employ both innate and adaptive immune responses to defend against pathogen infections and malignancy. Interferons and cytokines play pivotal roles in mediating and coordinating diverse aspects of the host immune response responsible for the clearance of infection and elimination of malignant cells. In addition, abnormal immune and/or inflammatory responses are closely linked to the pathogenesis of various human diseases such as infections, autoimmune diseases and cancer. Thus, a better understanding of these signaling pathways is essential to our efforts in developing more effective regimes to prevent and treat infectious diseases as well as to combat autoimmune diseases and cancer.     

Double-enkephalins—Synthesis,activity on guinea-pig ileum,and analgesic effect

We have synthesized enkephalin analogues in which C-terminal methionine or leucine residues are replaced by a second active fragment of the enkephalin analogue. Synthesis of two compounds is described: in one, two fragments of a D-Ala²-enkephalin analogue are connected by a -NH-NH-bridge, and in the other, three methylene groups are incorporated between the amino groups. The first compound is a very potent inhibitor of electrically induced contractions of guinea-pig ileum and produces a strong analgesia when administered intraperitoneally in mice. The second compound is less active on the ileum and fails to produce analgesia after systemic injection. The double-enkephalins may interact with μ-receptors.     

Toxigenic Pfiesteria species—Updates on biology,ecology, toxins,and impacts

The genus Pfiesteria includes two toxigenic species, Pfiesteria piscicida and Pfiesteria shumwayae, that are thinly thecate dinoflagellates with apparently cosmopolitan distribution, especially in shallow, poorly flushed, eutrophic estuaries. They are heterotrophic prey generalists that typically feed via phagotrophy and prefer live fish or their fresh tissues as food. They can also engage in limited mixotrophy through temporary retention of kleptochloroplasts from algal prey. Toxicity is highly variable among strains, ranging from apparently nontoxic to highly toxic. Some strains produce a group of hydrophilic toxins with metal-mediated free radical production. Various metals can be involved in the toxin congeners, and the purified toxins are highly labile. These toxins can adversely affect mammalian cells as well as fish. Toxic strains are capable of killing fish by both toxins and physical attack from feeding upon epidermis and other tissues. Non-inducible strains do not produce sufficient toxin to kill fish, but some are capable of causing larval fish death by physical attack. From 1991 to 1998, Pfiesteria spp. were linked to major kills of juvenile Atlantic menhaden (Brevoortia tyrannus), mostly at densities of ≥4(3) × 10² to 10³ (rarely, 10⁴) flagellate cells mL⁻¹. These kills mainly occurred in the second largest and largest estuaries on the U.S. mainland, especially two main tributaries of the Albemarle-Pamlico Estuarine System, following decades of hurricane-free conditions. Between kills, Pfiesteria abundance was low in surface waters (<10 cells mL⁻¹), and the available evidence suggests that the populations were mostly in the lower water column and within surficial sediments. Apparently highly sensitive to scouring effects from major storms, Pfiesteria populations have been sparse in the affected estuaries since several hurricanes struck the Albemarle-Pamlico in the late 1990s. Recent research highlights include characterization of a novel group of Pfiesteria toxins, culture of a toxigenic strain on a sterile fish cell line, axenic culture on a semi-defined medium, the discovery of a new mode of heterotrophic feeding in dinoflagellates as manifested by Pfiesteria, and other advances in understanding the nutritional ecology and prey acquisition of these harmful dinoflagellates.     

SNPs,SSRs and inferences on cassava’s origin

Despite its importance as a staple food throughout the tropics, the root crop cassava (it Manihot esculenta ssp. esculenta) has traditionally not been a major focus of research. One basic question about cassava that remained unresolved until recently concerns the crop’s origin. This paper describes analyses of SNPs (single nucleotide polymorphisms) and SSR (simple sequence repeat) variation as a means of tracing cassava’s evolutionary and geographical origins. Genetic diversity was examined in a sample of 20 cassava varieties that are representative of germplasm diversity within the crop, and in 212 individuals collected from wild populations of two closely related Manihot species. SNP and indel variation was examined in portions of two low copy nuclear genes, BglA and Hnl. Inferences from these genes were compared to those from previously examined loci, including the low copy nuclear gene G3pdh and 5 SSR loci. For all genes examined, SNPs and SSR alleles are shared between domesticated cassava and a specific geographical subset of wild Manihot populations, which suggests the following: (1) Cassava was likely domesticated from a single wild Manihot species, M. esculenta ssp. flabellifolia, rather than from multiple hybridizing species, as traditionally believed; and (2) the crop most likely originated in the southern Amazon basin.     

Class,race – and place: immigrants’ self-perceptions on inclusion,belonging and opportunities in Stockholm and Barcelona

Based on eighty-one in-depth interviews with immigrants and stakeholders performed in Stockholm and Barcelona, this article examines whether the relationship to place can mitigate the negative effects of rejection that racialized immigrants and minorities perceive from the ethnic majority society. The immigrant respondents’ perceptions and lived experiences of exclusion and discrimination lend support to the argument that it is necessary to link race and class in order to understand the particular “immigrant disadvantage,” but also reflect how attachment to the city or neighbourhood where they live can contribute to a sense of belonging: the respondents overall feel more included in Barcelona, where every day interethnic contacts are more frequent than in Stockholm.     

Mitochondrial dysfunction and biotransformation of β-carboline alkaloids,harmine and harmaline,on isolated rat hepatocytes

The cytotoxic effects and biotransformation of harmine and harmaline, which are known β-carboline alkaloids and potent hallucinogens, were studied in freshly isolated rat hepatocytes. The exposure of hepatocytes to harmine caused not only concentration (0–0.50 mM)- and time (0–3 h)-dependent cell death accompanied by the formation of cell blebs and the loss of cellular ATP, reduced glutathione, and protein thiols but also the accumulation of glutathione disulfide. Of the other analogues examined, the cytotoxic effects of harmaline and harmol (a metabolite of harmine) at a concentration of 0.5 mM were less than those of harmine. The loss of mitochondrial membrane potential and generation of oxygen radical species in hepatocytes treated with harmine were greater than those with harmaline and harmol. In the oxygen consumption of mitochondria isolated from rat liver, the ratios of state-3/state-4 respiration of these β-carbolines were decreased in a concentration-dependent manner. In addition, harmine resulted in the induction of the mitochondrial permeability transition (MPT), and the effects of harmol and harmaline were less than those of harmine. At a weakly toxic level of harmine (0.25 mM), it was metabolized to harmol and its monoglucuronide and monosulfate conjugates, and the amounts of sulfate rather than glucuronide predominantly increased with time. In the presence of 2,5-dichloro-4-nitrophenol (50 μM; an inhibitor of sulfotransferase), harmine-induced cytotoxicity was enhanced, accompanied by decrease in the amount of harmol-sulfate conjugate, due to an increase in the amount of unconjugated harmol and the inhibition of harmine loss. Taken collectively, these results indicate that (a) mitochondria are target organelles for harmine, which elicits cytotoxicity through mitochondrial failure related to the induction of the MPT, mitochondrial depolarization, and inhibition of ATP synthesis; and (b) the toxic effects of harmine are greater than those of either its metabolite harmol or its analogue harmaline, suggesting that the onset of harmine-induced cytotoxicity may depend on the initial and/or residual concentrations of harmine rather than on those of its metabolites.     

THE SHOULDER JOINT—Observations on Comparative Anatomy,Physiology, and Treatment

In a visual study of human and simian function of the shoulder joint, manifest superiority of the latter was noted. Comparative anatomical studies tend to confirm these observations and indicate that many common affections of the shoulder in humans may stem from incomplete evolutionary adaptation.Certain anatomical clues may lead to improvements in conservative and surgical treatment.A regimen of conservative and operative treatment developed over a period of many years has been found to be clinically effective for the relief of chronic refractory shoulder pain. These techniques differ at many points from present practices of a majority of physicians who deal with diseases of the shoulder.     

β-alanine use by Ebony and normal Drosophila melanogaster with notes on glucose,uracil, dopa,and dopamine

Following injection of newly formed female pupae or adult Drosophila with C ¹⁴ -labeled -alanine, appreciable labeled free -alanine was retained in the internal organs for at least 24 hr. Ebony retained most, while heterozygotes were intermediate. Part of the -alanine-2-C-labeled portion of the molecule was bound to the internal organs, especially the ovaries and mature egg follicles. Dissected normal pupal cuticles incorporate -alanine-1-C as directly related to the degree of tanning. KCN, ethanol, or air exclusion inhibit incorporation. Tan pigment and radioactivity are extractable from the cuticles by hydrazine-ethanol. A -alanine precursor is uracil. Injected -alanine immobilizes ebony, but not normal, flies (newly emerged) and inhibits glucose, but not glucose 6-phosphate metabolism. Desiccated ebony adults take up water more readily than normal adults.Aided by Public Health Service Award GM 12435.     

Adsorption of Adenine, Cytosine, Thymine, and Uracil on Sulfide-Modified Montmorillonite: FT-IR, M?ssbauer and EPR Spectroscopy and X-Ray Diffractometry Studies

In the present work the interactions of nucleic acid bases with and adsorption on clays were studied at two pHs (2.00, 7.00) using different techniques. As shown by Mössbauer and EPR spectroscopies and X-ray diffractometry, the most important finding of this work is that nucleic acid bases penetrate into the interlayer of the clays and oxidize Fe²⁺ to Fe³⁺, thus, this interaction cannot be regarded as a simple physical adsorption. For the two pHs the order of the adsorption of nucleic acid bases on the clays was: adenine????cytosine?>?thymine?>?uracil. The adsorption of adenine and cytosine on clays increased with decreasing of the pH. For unaltered montmorillonite this result could be explained by electrostatic forces between adenine/cytosine positively charged and clay negatively charged. However for montmorillonite modified with Na₂S, probably van der Waals forces also play an important role since both adenine/cytosine and clay were positively charged. FT-IR spectra showed that the interaction between nucleic acid bases and clays was through NH⁺ or NH ₂ ⁺ groups. X-ray diffractograms showed that nucleic acid bases adsorbed on clays were distributed into the interlayer surface, edge sites and external surface functional groups (aluminol, silanol) EPR spectra showed that the intensity of the line g????2 increased probably because the oxidation of Fe²⁺ to Fe³⁺ by nucleic acid bases and intensity of the line g?=?4.1 increased due to the interaction of Fe³⁺ with nucleic acid bases. Mössbauer spectra showed a large decreased on the Fe²⁺ doublet area of the clays due to the reaction of nucleic acid bases with Fe²⁺.     

Effect of prolyl-leucyl-glycinamide and α-melanocyte-stimulating hormone on levorphanol-induced analgesia,tolerance and dependence

Prolyl-leucyl-glycinamide (PLG) at a low dose (10 ng/mouse) administered by an intracerebroventricular (i.c.v.) injection did not affect levorphanol analgesia, but PLG at higher doses (10 and 100 μg/mouse) and α-melanocyte-stimulating hormone (α-MSH) (10 ng/ mouse) antagonized levorphanol analgesia. Development of levorphanol tolerance was facilitated by 10 ng/mouse of PLG, unaffected by 10 μg/mouse of PLG, but antagonized by 100 μg/mouse of PLG and 10 ng/mouse of α-MSH. The effect of PLG on levorphanol dependence was assessed by changes in body weight and temperature during naloxone-induced withdrawal. PLG (10 ng/mouse) facilitated the development of levorphanol dependence, but 10 μg/mouse of PLG had no effect. PLG (100 μg/mouse) antagonized development of levorphanol dependence. PLG at doses of 10 and 100 μg/mouse precipitated withdrawal in levorphanol-dependent mice. α-MSH (10 ng/mouse) antagonized development of levorphanol dependence as evidenced by an increase in the ED50 of naloxone required to induce withdrawal jumping. These results indicate that PLG and α-MSH affected levorphanol-induced analgesia, tolerance and dependence in a qualitatively similar manner to their effect on morphine-induced analgesia, tolerance and dependence.     

Impact of the spatial scale of grass–legume mixtures on sheep grazing behaviour,preference and intake,and subsequent effects on pasture

The benefits of using white clover in pastures have been widely recognised for many years. However, clover is perceived as being unreliable because of its typically low content, which is spatially and temporally variable, in mixed pastures. One proposed solution to increase the proportion of clover in the diet of grazing animals and composition in the pasture is to spatially separate clover from grass within the same field. In a field experiment ryegrass and white clover were grown in fine mixtures, and in pure alternating strips of ryegrass and clover of 1.5 m, 3 m or 18 m width within a field. Pastures were grazed for two grazing periods of 9 and 12 weeks, and measurements of sward surface height (SSH), herbage mass and composition and clover morphology were taken. Grazing behaviour was also observed. Results showed that spatial separation in the long term, when compared with a fine mixture, increased clover availability (18% to 30% v. 9%, based on standing dry matter) and was not grazed to extinction. Ewes maintained their preference for clover throughout the experiment (selection coefficient 2 to 5), which resulted in a reduction in the SSH of clover in monocultures to <3 cm and significant changes to the morphology of clover (smaller leaves, shorter petioles and thicker stolon), at the expense of maximising their intake. Spatial separation in the short term may therefore allow grazing animals to select their preferred diet; however, in the long term in continuously grazed pasture, their preference for clover depletes its availability.     

Induction and specification of midbrain dopaminergic cells: focus on SHH,FGF8, and TGF-β

Cell-fate decisions along the dorsoventral and anterior–posterior axis of the neural tube are dictated by factors from signaling and organizing centers. According to the prevailing notion, the formation of mesencephalic dopaminergic neurons is directed by diffusable signals from the notochord, floor plate, and isthmic organizer. Sonic hedgehog (Shh), secreted by the notochord and floor plate, and fibroblast growth factor (FGF) 8, secreted by the isthmus, are thought to be key molecules involved in the development of midbrain dopaminergic neurons. During the last decade, the introduction of elegant explant culture systems and the generation of transgenic and mutant mice have greatly contributed to a better understanding of the molecular signals that direct the induction and specification of midbrain dopaminergic neurons. In this context, experimental evidence has challenged the dominant roles of Shh and FGF8 in dopaminergic neuron development. Additional molecules have been identified as being required for the generation of mesencephalic dopaminergic neurons, particularly members of the transforming growth factor beta superfamily. The work carried out in the authors laboratories was supported by grants from the Deutsche Forschungsgemeinschaft     

Distinct morphological and mito-inhibitory effects induced by TGF-β1, HGF and EGF on mouse,rat and human hepatocytes

TGF-1 is known as a potent inhibitor of proliferation of rat and human hepatocytes. In this study we show that the effects of TGF-1 are quite different on mouse hepatocytes. In rat and human hepatocytes, TGF-1 inhibited DNA synthesis and also inhibited the morphological changes induced by growth factors in rat and human hepatocytes. In contrast, addition of TGF-1 to mouse hepatocytes resulted in pronounced alterations in morphology of these cells. These changes were similar to those induced by HGF and EGF. The induction of structural changes by TGF-1 was noted only in mouse hepatocytes. Mouse hepatocytes were also much more resistant to the mito-inhibitory effect of TGF-1. These findings suggest profound differences in hepatocyte growth regulation between these species and may relate to observed differences in susceptibility to carcinogenesis.Abbreviations EGF epidermal growth factor - HGF hepatocyte growth factor - SF scatter factor - TGF-1 transforming growth factor beta type one