Burnout in medical students.

Only a small number of studies have examined the relationship between medical students and burnout syndrome. In Salzburg, Paracelsus Private Medical University (PMU) offers a 5­year medical program instead of the regular 6 years of medical studies. Due to the tight schedule and heavy workload, the stress level of students is high. The purpose of this study was to determine whether PMU students show burnout symptoms. Three surveys were conducted: at the beginning of the academic year (T1, December 2009), at the end of the academic year (T2, June 2010), and at the beginning of the following academic year (T3, December 2010). For the assessment of burnout, the Maslach Burnout Inventory (emotional exhaustion, depersonalization or cynicism, and low personal accomplishment) was used, as well as the Six Factors Theory of Burnout (workload, control, reward, community, fairness, and values) and for comparison, the Austrian norms developed by Unterholzer. Burnout rate was calculated by a combined measure of the three components. The results show a significant difference from the norm means in emotional exhaustion, depersonalization/cynicism, and low personal accomplishment. With regard to areas of work life, all values are below the means, indicating high workload, high external control, low reward, low feeling of community, and low fairness-except values, i.e., motivation of the students. The mean overall burnout frequency turned out to be 47.8 ± 11.0%, whereas females have slightly higher burnout rates than males. An increasing linear trend with burnout rates was seen from the youngest to the oldest class. In addition, the estimated burnout rate increased within the academic term, as T2 had the highest rate, followed by T3, and the lowest rate was seen in T1. In conclusion, burnout in medical students is frequent and significantly related to heavy workload and other factors of worklife, necessitating changes of academic and organizational settings of medical curricula.

Polyphenol supplementation inhibits physiological increase of prostaglandin E2 during reproductive period - A randomized clinical trial.

Anti-inflammatory property of polyphenols and their effect on the metabolism of prostaglandins is not established in healthy humans. This study aimed to evaluate the effect of polyphenol supplementation in plasma levels of prostaglandin E2 and other markers of inflammation and oxidative stress in women using contraceptives. In this randomized double-blind clinical trial, women aged 25-35 years were selected. Participants received capsules containing polyphenols or placebo, to be consumed for fifteen days. From 40 women randomized, 28 completed the study. Control group showed a significant increase in the levels of PGE2 (p=0.01) while the polyphenols group showed no change in these levels (p=0.79). There was an increase in hs-CRP (p<0.01) and F2-isoprostane (p=0.04) in the control group. The GSSG to GSH ratio significantly reduced in the polyphenols group (p=0.02). Supplementation with polyphenol capsules inhibited the increase in markers of inflammation and oxidative stress in women of childbearing age using combined hormonal contraceptives.

Increase of prostaglandin E2 in the reversal of fetal ductal constriction after polyphenol restriction.

OBJECTIVE: Anti-inflammatory substances that inhibit the synthesis of prostaglandins, such as non-steroidal anti-inflammatory drugs (NSAIDs) and polyphenol-rich foods, can cause constriction of the fetal ductus arteriosus. This study aimed to test the hypothesis that reversal of fetal ductal constriction after maternal restriction of polyphenol-rich foods, in the third trimester of pregnancy, is accompanied by increased plasma levels of prostaglandin E2 (PGE2). METHODS: This was a controlled clinical trial of women with singleton pregnancy ≥ 28 weeks undergoing fetal echocardiography. The intervention group included pregnancies with diagnosis of fetal ductal constriction and not exposed to NSAIDs. The control group consisted of third-trimester normal pregnancies. Both groups answered a food frequency questionnaire to assess the amount of total polyphenols in their diet, underwent Doppler echocardiographic examination and had blood samples collected for analysis of plasma levels of PGE2. Intervention group participants received dietary guidance to restrict the intake of polyphenol-rich foods. The assessments were repeated after 2 weeks in both groups. RESULTS: Forty normal pregnancies were assessed in the control group and 35 with fetal ductal constriction in the intervention group. Mean maternal age (26.6 years) and mean body mass index (30.12 kg/m2 ) were similar between the two groups. Intragroup analysis showed that dietary guidance reduced the median consumption of polyphenols (from 1234.82 to 21.03 mg/day, P < 0.001), increasing significantly the plasma concentration of PGE2 (from 1091.80 to 1136.98 pg/mL, P < 0.05) in the intervention group after 2 weeks. In addition, Doppler echocardiography showed reversal of fetal ductal constriction in the intervention group. No significant changes were observed in the control group. CONCLUSIONS: Dietary intervention for maternal restriction of polyphenol-rich foods in the third trimester of pregnancy is accompanied by increase in plasma levels of PGE2 and reversal of fetal ductal constriction. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

First record of second-generation facultative parthenogenesis in a vertebrate species, the whitespotted bambooshark Chiloscyllium plagiosum.

In this study, two parthenogenetic events within a family of the whitespotted bambooshark Chiloscyllium plagiosum are reported. A captive female produced multiple parthenogens. Unexpectedly, a single specimen of a total of nine parthenogens displayed external claspers characterizing the male sex in chondrichthyans. Upon dissection, internal sexual organs of this specimen were malformed or absent; however, the presence of claspers in this study challenges the as yet assumed sex determination system in this shark species. Even more remarkable was that one of the female parthenogens reproduced asexually again producing viable offspring. As far as is known, this is the first genetically confirmed evidence for second-generation facultative parthenogenesis in vertebrates. These results support the evolutionary significance of parthenogenesis as an alternative to sexual reproduction.

Are shoals of minnow Phoxinus phoxinus formed by close kin?

A molecular analysis examining the level of relatedness in shoaling minnows Phoxinus phoxinus was conducted. The results revealed that individuals from within the same shoal were not more closely related to each other than to individuals from other shoals. This led to the conclusion that Schreckstoff may be less likely to have evolved in the context of kin selection.

Major histocompatibility complex variability in the clonal Amazon molly, Poecilia formosa: is copy number less important than genotype?

The evolution of sex is still a major unsolved puzzle in biology. One of the most promising theoretical models to answer this question is the Red Queen hypothesis. The Red Queen hypothesis proposes a fast adaptation of pathogens to common genotypes and therefore a negative frequency-dependent selection against common genotypes. Clonal organisms should be especially endangered when co-occurring with closely related sexual species. In this context, major histocompatibility (MHC) genes have been discussed to be auspicious candidates that could provide the genetic basis on which selection for immune competence could act. In this study, we investigated MHC variability in a clonal teleost fish: the Amazon molly, Poecilia formosa. The Amazon molly is an ideal candidate to test the Red Queen hypothesis as it is a clonal species but co-occurs with a closely related sexual species and should therefore be especially susceptible to pathogen infection. We found that allele numbers did in general not differ between sexual and clonal 'species' but that genotypic variability is reduced in the clonally reproducing fish, especially in the polyploids. We conclude that in clonal organisms, genotype frequency might be more important for immune competence than MHC allele number. Amazon mollies and their co-occurring parental species clearly fulfil a prerequisite of the Red Queen hypothesis and should therefore provide an ideal system to experimentally test this basic principle probably underlying the evolution of sex.

The origin and evolution of a unisexual hybrid: Poecilia formosa.

Clonal reproduction in vertebrates can always be traced back to hybridization events as all known unisexual vertebrates are hybrids between recognized species or genetically defined races. Interestingly, clonal vertebrates often also rely on interspecific matings for their reproduction because gynogenesis (sperm-dependent parthenogenesis) and hybridogenesis are common modes of propagation. While in most cases these hybridization events leave no hereditary traces in the offspring, occasionally the genome exclusion mechanism fails and either small parts of male genetic material remain inside the oocyte in the form of microchromosomes, or fusion of the sperm nucleus with the oocyte nucleus leads to polyploid individuals. In this review, we highlight the important role of hybridization for the origin and evolution of a unisexual hybrid: the Amazon molly, Poecilia formosa.

Facultative parthenogenesis in vertebrates: reproductive error or chance?

Parthenogenesis, the development of an embryo from a female gamete without any contribution of a male gamete, is very rare in vertebrates. Parthenogenetically reproducing species have, so far, only been found in the Squamate reptiles (lizards and snakes). Facultative parthenogenesis, switching between sexual and clonal reproduction, although quite common in invertebrates, e.g. Daphnia and aphids, seems to be even rarer in vertebrates. However, isolated cases of parthenogenetic development have been reported in all vertebrate groups. Facultative parthenogenesis in vertebrates has only been found in captive animals but might simply have been overlooked in natural populations. Even though its evolutionary impact is hard to determine and very likely varies depending on the ploidy restoration mechanisms and sex-determining mechanisms involved, facultative parthenogenesis is already discussed in conservation biology and medical research. To raise interest for facultative parthenogenesis especially in evolutionary biology, I summarize the current knowledge about facultative parthenogenesis in the different vertebrate groups, introduce mechanisms of diploid oocyte formation and discuss the genetic consequences and potential evolutionary impact of facultative parthenogenesis in vertebrates.

A haploid-diploid-triploid mosaic of the Amazon molly, Poecilia formosa.

We report the finding of the first haploid-diploid-triploid mosaic fish from the family Poeciliidae. The animal was derived from a laboratory cross of a female F1 hybrid of Poecilia mexicana and P. latipinna with a male from an ornamental strain derived from P. mexicana and P. sphenops (Black molly). It was identified because of its unusual pigmentation pattern and molecular methods (flow cytometry, NOR staining) confirmed its mosaic genotype. The mode of mosaic formation and the possible importance for poeciliid fish evolution are discussed.

Risk factors for conduct disorder among Navajo Indian men and women.

OBJECTIVES: To describe the risk factors for conduct disorder before age 15 among Navajo Indians. METHODS: The study was based on a survey of a stratified random sample of adult Navajo Indians between the ages of 21 and 65 living on and adjacent to two different areas of the Navajo Reservation. There were 531 male and 203 female respondents. The average age (SD) of the men was 38.7 (10.5) years and of the women 35.5 (9.0) years. Conduct disorder was diagnosed retrospectively using the Diagnostic Interview Schedule first developed for the Epidemiological Catchment Area study. The responses were combined into a continuous scale. RESULTS: Significant risk factors for increased scores on the conduct disorder scale were: histories of physical and sexual abuse in childhood; abusive maternal drinking; a small number of households per camp; younger age; and being male rather than female. Measures of social status and religion in which subjects were raised were not significant. CONCLUSIONS: Many of the risk factors that are associated with conduct disorder in other populations are also risk factors in the Navajo population. There is suggestive evidence that some of these risk factors have become more common since World War II, raising the possibility that conduct disorder has become more prevalent, as is thought to be the case nationwide.

Alcohol dependence and conduct disorder among Navajo Indians.

OBJECTIVE: The purpose of this study is to examine the association between conduct disorder before age 15 and subsequent alcohol dependence, and to describe the lifetime prevalence of alcohol dependence among Navajo Indian women and men. METHOD: This was a case-control design which included both men (n = 735) and women (n = 351) and in which the Diagnostic Interview Schedule was used for the diagnosis of the lifetime history of alcohol dependence and conduct disorder. Alcohol dependent cases were selected from inpatient and outpatient treatment programs (204 men, 148 women). Whenever possible, controls were matched for age, sex and community of residence and were randomly selected and interviewed until a nonalcohol dependent individual was found. Among the men, there were 374 alcohol dependent controls and 157 nonalcohol dependent controls. Among the women, the figures were 60 and 143, respectively. When combined, the controls comprise samples of the adult male and female populations from which estimates of lifetime prevalence of alcohol dependence, and of the amount of alcohol dependence in the population attributable to conduct disorder, may be inferred. RESULTS: Conduct disorder is a risk factor for alcohol dependence among both men and women. Lifetime prevalence of alcohol dependence in this population is high (70.4% for men and 29.6% for women), but the amount of alcohol dependence in the population attributable to conduct disorder is low. On the other hand, among the alcohol dependent, those with conduct disorder had the most severe alcohol- and nonalcohol-related problems. CONCLUSIONS: The potential limitations of the study are those common to case-control designs, especially biased recall by cases. There are also potential sampling biases among the controls. It is shown that none of the potential biases invalidate the findings, which support the hypothesis that in this population conduct disorder is a risk for alcohol dependence. The implications for primary prevention of alcohol dependence are discussed.

Expression of matrix metalloproteinases and their tissue inhibitors in human brain tumors.

In this study, we investigated the expression patterns of 15 matrix metalloproteinases (MMPs) and three tissue inhibitors of metalloproteinase in gliomas, medulloblastomas, and normal brain tissue. By Northern blot analysis we found increased levels of mRNAs encoding for gelatinase A, gelatinase B, two membrane-type MMPs (mt1- and mt2-MMP), and tissue inhibitors of metalloproteinase-1 in glioblastomas and medulloblastomas. We observed a significant increase of mt1-MMP, gelatinase A, gelatinase B, and tissue inhibitors of metalloproteinase-1 in glioblastomas as compared with low-grade astrocytomas, anaplastic astrocytomas, and normal brain. In medulloblastomas, the expression of mt1-MMP, mt2-MMP, and gelatinase A were also increased, but to a lesser extent than that observed in glioblastomas. These data were confirmed at the protein level by immunostaining analysis. Moreover, substrate gel electrophoresis showed that the activated forms of gelatinases A and B were present in glioblastomas and medulloblastomas. These results suggest that increased expression of mt1-MMP/gelatinase A is closely related to the malignant progression observed in gliomas. Furthermore, the present study demonstrates, to our knowledge for the first time, that medulloblastomas express high levels of MMP.

Surveillance of St. Louis encephalitis virus vectors in Grand Junction, Colorado, in 1987.

Grand Junction, Colorado, was the site of a St. Louis encephalitis (SLE) outbreak in 1985. Epidemiologic and ecologic investigations in 1985 and 1986 suggested that Culex tarsalis may not have been the exclusive vector in the outbreak and that Cx. pipiens may have contributed to transmission as an accessory vector. A limited field study in 1987 generally confirmed observations from 1986 that Cx. pipiens was more abundant than Cx. tarsalis in late summer when SLE virus transmission normally occurs. In both years, infection rates in Cx. tarsalis were higher than in Cx. pipiens, but in 1987 the only SLE virus isolate from Cx. pipiens was obtained early in the season. Truck trap collections showed that Cx. pipiens was the principal vector species collected, comprising 86% of the total. Light trap collections underestimated the population of Cx. pipiens; gravid trap collections gave a closer approximation of the relative proportions of Cx. pipiens and Cx. tarsalis in the vector mosquito population after midsummer.

Entomologic studies after a St. Louis encephalitis epidemic in Grand Junction, Colorado.

In 1986, after a St. Louis encephalitis epidemic in Grand Junction, Colorado, in 1985, vector mosquitoes in the city were surveyed to correlate their bionomics and infection rates with the occurrence of human disease. No human cases were reported, but mosquito surveillance disclosed St. Louis encephalitis virus in Culex tarsalis and Culex pipiens pipiens. Mosquitoes were collected with gravid traps designed to attract Cx. p. pipiens and with Centers for Disease Control light traps. Culex p. pipiens was the predominant vector mosquito collected and was captured chiefly in gravid traps. The Culex tarsalis population emerged and expanded approximately one month earlier than did the Cx. p. pipiens population. Consequently, Cx. p. pipiens was the predominant vector species after August. Infection rates throughout the surveillance period (June to September) were severalfold higher in Cx. tarsalis than in Cx. p. pipiens; however, in late summer, diminished numbers of Cx. tarsalis and a persistent population of Cx. p. pipiens resulted in relatively larger numbers of infected Cx. p. pipiens. Thus, the participation of Cx. p. pipiens as a St. Louis encephalitis vector would have been underestimated in previous studies employing light traps alone. These studies provide further evidence that Cx. p. pipiens-associated urban St. Louis encephalitis and rural Cx. tarsalis-associated St. Louis encephalitis cycles may coexist in the West.

Epidemiologic aspects of a St. Louis encephalitis outbreak in Mesa County, Colorado.

An epidemic of St. Louis encephalitis in 1985 in Mesa County, Colorado, led to 17 cases, including one fatality. Risk was associated with advanced age and residence in Grand Junction, the county's principal city. A trend was observed toward higher risk in females. However, increased risk in females was not associated with higher infection rates (increased exposure). Capture enzyme immunoassays detected specific immunoglobulin M (IgM) and immunoglobulin A after infection. A serosurvey of Grand Junction residents disclosed an infection rate of 4.0%, indicating that 1,123 epidemic St. Louis encephalitis infections may have occurred in the city. Evidence of previous St. Louis encephalitis virus infection was found in 11.2% of survey respondents who had neutralizing antibody to the virus without specific IgM. The prevalence of St. Louis encephalitis virus antibody was similar to rates observed in serosurveys undertaken 30 years earlier, indicating that the level of endemic St. Louis encephalitis transmission in the city had not changed appreciably in that interval.

Life sciences: radiobiological advanced biostack experiment.

The radiobiological properties of the heavy ions of cosmic radiation were investigated on Spacelab 1 by use of biostacks, monolayers of biological test organisms sandwiched between thin foils of different types of nuclear track detectors. Biostacks were exposed to cosmic radiation at several locations with different shielding environments in the module and on the pallet. Evaluations of the physical and biological components of the experiment to date indicate that in general they survived the spaceflight in good condition. Dosimetric data are presented for the different shielding environments.

[Thermographic investigations of thyroid foci (author's transl)]. / Ergebnisse plattenthermographischer Untersuchungen von Schilddrüsenknoten.

Thyroid foci showing uptake on scintigraphy were examined by thermography and compared with foci showing no uptake. The following results were obtained: 1. One fifth of scintigraphically "cold" foci were also cold on the thermogram. 2. Two thirds to four fifths of foci showing scintigraphic uptake appeared as warm spots on the thermogram. 3. 10% of foci showing no uptake appeared as thermographic circumscribed hot spots. The combination of findings in "3" is suspicious of malignancy and this justifies the use of thermography in addition to scintigraphy and cytology.