88 research outputs found
Seeking creativity: A case study on information problem solving in professional music
This study explored the information seeking behavior of a professional jazz musician during creative work. It aimed at revealing information seeking activities necessary to execute present-day musical projects. A single case was studied in depth. First, a narrative interview was conducted to reveal project phases and corresponding information seeking behavior. Second, hereupon a semi-structured interview was taken to identify information seeking activities per phase. Results indicate that the musician deliberately searched for musical information especially in the first project phases. The internet was used as main source. Both data and goal driven strategies were applied, of which the latter were relatively scarce. This means that in this case the musician sporadically searched information based on a contemplated search plan. Future research should aim at generalizing findings of this case. It should further validate the underlying analytical framework that proved to be useful for describing and categorizing musical information seeking behavior
Study on the short-term effects of increased alcohol and cigarette consumption in healthy young men's seminal quality
Many studies have reported a negative impact of lifestyle factors on testicular function, spermatozoa parameters and pituitary-gonadal axis. However, conclusions are difficult to draw, since studies in the general population are rare. In this study we intended to address the early and late short-term impact of acute lifestyle alterations on young men's reproductive function. Thirty-six healthy male students, who attended the Portuguese academic festivities, provided semen samples and answered questionnaires at three time-points. The consumption of alcohol and cigarette increased more than 8 and 2 times, respectively, during the academic festivities and resulted in deleterious effects on semen quality: one week after the festivities, a decrease on semen volume, spermatozoa motility and normal morphology was observed, in parallel with an increase on immotile spermatozoa, head and midpiece defects and spermatozoa oxidative stress. Additionally, three months after the academic festivities, besides the detrimental effect on volume, motility and morphology, a negative impact on spermatozoa concentration was observed, along with a decrease on epididymal, seminal vesicles and prostate function. This study contributed to understanding the pathophysiology underlying semen quality degradation induced by acute lifestyle alterations, suggesting that high alcohol and cigarette consumption are associated with decreased semen quality in healthy young men.publishe
Fish consumption patterns and hair mercury levels in children and their mothers in 17 EU countries
The toxicity of methylmercury (MeHg) in humans is well established and the main source of exposure is via the consumption of large marine fish and mammals. Of particular concern are the potential neurodevelopmental effects of early life exposure to low-levels of MeHg. Therefore, it is important that pregnant women, children and women of childbearing age are, as far as possible, protected from MeHg exposure.Within the European project DEMOCOPHES, we have analyzed mercury (Hg) in hair in 1799 mother–child pairs from 17 European countries using a strictly harmonized protocol for mercury analysis. Parallel, harmonized questionnaires on dietary habits provided information on consumption patterns of fish and marine products. After hierarchical cluster analysis of consumption habits of the mother–child pairs, the DEMOCOPHES cohort can be classified into two branches of approximately similar size: one with high fish consumption (H) and another with low consumption (L). All countries have representatives in both branches, but Belgium, Denmark, Spain, Portugal and Sweden have twice as many or more mother–child pairs in H than in L. For Switzerland, Czech Republic, Hungary, Poland, Romania, Slovenia and Slovakia the situation is the opposite, with more representatives in L than H.There is a strong correlation (r=0.72) in hair mercury concentration between the mother and child in the same family, which indicates that they have a similar exposure situation. The clustering of mother–child pairs on basis of their fish consumption revealed some interesting patterns. One is that for the same sea fish consumption, other food items of marine origin, like seafood products or shellfish, contribute significantly to the mercury levels in hair. We conclude that additional studies are needed to assess and quantify exposure to mercury from seafood products, in particular. The cluster analysis also showed that 95% of mothers who consume once per week fish only, and no other marine products, have mercury levels 0.55 µg/g. Thus, the 95th percentile of the distribution in this group is only around half the US-EPA recommended threshold of 1 µg/g mercury in hair. Consumption of freshwater fish played a minor role in contributing to mercury exposure in the studied cohort.The DEMOCOPHES data shows that there are significant differences in MeHg exposure across the EU and that exposure is highly correlated with consumption of fish and marine products. Fish and marine products are key components of a healthy human diet and are important both traditionally and culturally in many parts of Europe. Therefore, the communication of the potential risks of mercury exposure needs to be carefully balanced to take into account traditional and cultural values as well as the potential health benefits from fish consumption. European harmonized human biomonitoring programs provide an additional dimension to national HMB programs and can assist national authorities to tailor mitigation and adaptation strategies (dietary advice, risk communication, etc.) to their country’s specific requirements
Regulatory RNAs and chromatin modification in dosage compensation: A continuous path from flies to humans?
Chromosomal sex determination is a widely distributed strategy in nature. In the most classic scenario, one sex is characterized by a homologue pair of sex chromosomes, while the other includes two morphologically and functionally distinct gonosomes. In mammalian diploid cells, the female is characterized by the presence of two identical X chromosomes, while the male features an XY pair, with the Y bearing the major genetic determinant of sex, i.e. the SRY gene. In other species, such as the fruitfly, sex is determined by the ratio of autosomes to X chromosomes. Regardless of the exact mechanism, however, all these animals would exhibit a sex-specific gene expression inequality, due to the different number of X chromosomes, a phenomenon inhibited by a series of genetic and epigenetic regulatory events described as "dosage compensation". Since adequate available data is currently restricted to worms, flies and mammals, while for other groups of animals, such as reptiles, fish and birds it is very limited, it is not yet clear whether this is an evolutionary conserved mechanism. However certain striking similarities have already been observed among evolutionary distant species, such as Drosophila melanogaster and Mus musculus. These mainly refer to a) the need for a counting mechanism, to determine the chromosomal content of the cell, i.e. the ratio of autosomes to gonosomes (a process well understood in flies, but still hypothesized in mammals), b) the implication of non-translated, sex-specific, regulatory RNAs (roX and Xist, respectively) as key elements in this process and the location of similar mediators in the Z chromosome of chicken c) the inclusion of a chromatin modification epigenetic final step, which ensures that gene expression remains stably regulated throughout the affected area of the gonosome. This review summarizes these points and proposes a possible role for comparative genetics, as they seem to constitute proof of maintained cell economy (by using the same basic regulatory elements in various different scenarios) throughout numerous centuries of evolutionary history
Electromagnetic radiation at 900 MHz induces sperm apoptosis through bcl-2, bax and caspase-3 signaling pathways in rats
Comparative proteomic network signatures in seminal plasma of infertile men as a function of reactive oxygen species
Reactive oxygen species and male reproductive hormones
Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies
on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous
and endogenous factors that are able to induce excessive production of reactive oxygen species (ROS) beyond that of
cellular antioxidant capacity, thus causing oxidative stress. In turn, oxidative stress negatively affects male reproductive
functions and may induce infertility either directly or indirectly by affecting the hypothalamus-pituitary-gonadal (HPG)
axis and/or disrupting its crosstalk with other hormonal axes. This review discusses the important exogenous and
endogenous factors leading to the generation of ROS in different parts of the male reproductive tract. It also highlights
the negative impact of oxidative stress on the regulation and cross-talk between the reproductive hormones. It further
describes the mechanism of ROS-induced derangement of male reproductive hormonal profiles that could ultimately
lead to male infertility. An understanding of the disruptive effects of ROS on male reproductive hormones would
encourage further investigations directed towards the prevention of ROS-mediated hormonal imbalances, which in turn
could help in the management of male infertility
Abscesses of the spleen: Report of three cases
Abscess of the spleen is a rare discovery, with about 600 cases in the international literature so far. Although it may have various causes, it is most usually associated with trauma and infections of the spleen. The latter are more common in the presence of a different primary site of infection, especially endocarditis or in cases of ischemic infarcts that are secondarily infected. Moreover, immunosuppression is a major risk factor. Clinical examination usually reveals a combination of fever, left-upper-quadrant abdominal pain and vomiting. Laboratory findings are not constant. Imaging is a necessary tool for establishing the diagnosis, with a choice between ultrasound and computed tomography. Treatment includes conservative measures, and surgical intervention. In children and in cases of solitary abscesses with a thick wall, percutaneous catheter drainage may be attempted. Otherwise, splenectomy is the preferred approach in most centers. Here, we present three cases of splenic abscess. In all three, splenectomy was performed, followed by rapid clinical improvement. These cases emphasize that current understanding of spleen abscess etiology is still limited, and a study for additional risk factors may be necessary
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