803 research outputs found
Institutional management of greenhouse gas emissions: How much does 'green' reputation matter?
Climate Change, green reputation, conjoint analysis, Environmental Economics and Policy, Resource /Energy Economics and Policy, Q29, Q40, Q51,
Idiopathic central precocious puberty in girls: presentation factors
<p>Abstract</p> <p>Background</p> <p>It is sometimes difficult to distinguish between premature thelarche and precocious puberty in girls who develop breasts before the age of 8 years. We evaluated the frequencies of the signs associated with breast development and the factors influencing the presentation of girls with idiopathic central precocious puberty (CPP).</p> <p>Methods</p> <p>353 girls monitored 0.9 ± 0.7 year after the onset of CPP.</p> <p>Results</p> <p>The age at CPP was < 3 years in 2%, 3â7 years in 38% and 7â8 years in 60% of cases. Pubic hair was present in 67%, growth rate greater than 2 SDS in 46% and bone age advance greater than 2 years in 33% of cases. Breast development was clinically isolated in 70 (20%) cases. However, only 31 of these (8.8% of the population) had a prepubertal length uterus and gonadotropin responses to gonadotropin releasing hormone and plasma estradiol. The clinical picture of CPP became complete during the year following the initial evaluation.</p> <p>25% of cases were obese. The increase in weight during the previous year (3.7 ± 1.4 kg) and body mass index were positively correlated with the statural growth and bone age advance (P < 0.0001).</p> <p>There was no relationship between the clinical-biological presentation and the age at puberty, the interval between the onset of puberty and evaluation, or the presence of familial CPP.</p> <p>Conclusion</p> <p>The variation in presentation of girls with CPP does not depend on their age, interval between the onset and evaluation, or familial factors. This suggests that there are degrees of hypothalamic-pituitary-ovarian activation that are not explained by these factors.</p
COVID-19 and mass incarceration: a call for urgent action
As of September 23, 2020, the USA had both the highest
number of COVID-19 cases and the largest incarcerated
population in the world. Approximately 2·3 million
people are currently incarcerated in prisons and jails in
the USA. More than 6·5 million individuals are under
daily correctional supervision, which includes probation
and parole, representing 2·6% of the entire US adult
population
Clinical relevance of biomarkers of oxidative stress
SIGNIFICANCE
Oxidative stress is considered to be an important component of various diseases. A vast number of methods have been developed and used in virtually all diseases to measure the extent and nature of oxidative stress, ranging from oxidation of DNA to proteins, lipids, and free amino acids. Recent Advances: An increased understanding of the biology behind diseases and redox biology has led to more specific and sensitive tools to measure oxidative stress markers, which are very diverse and sometimes very low in abundance.
CRITICAL ISSUES
The literature is very heterogeneous. It is often difficult to draw general conclusions on the significance of oxidative stress biomarkers, as only in a limited proportion of diseases have a range of different biomarkers been used, and different biomarkers have been used to study different diseases. In addition, biomarkers are often measured using nonspecific methods, while specific methodologies are often too sophisticated or laborious for routine clinical use.
FUTURE DIRECTIONS
Several markers of oxidative stress still represent a viable biomarker opportunity for clinical use. However, positive findings with currently used biomarkers still need to be validated in larger sample sizes and compared with current clinical standards to establish them as clinical diagnostics. It is important to realize that oxidative stress is a nuanced phenomenon that is difficult to characterize, and one biomarker is not necessarily better than others. The vast diversity in oxidative stress between diseases and conditions has to be taken into account when selecting the most appropriate biomarker. Antioxid. Redox Signal. 00, 000-000
Breast cancer and childhood anthropometry: emerging hypotheses?
In this issue of Breast Cancer Research, Baer and colleagues report a strong protective effect of childhood and adolescent body fatness on premenopausal breast cancer risk based on a large prospective study. Methodological issues are discussed, as are tentative biological interpretations regarding the findings
Evaluation of effectiveness of instruction and study habits in two consecutive clinical semesters of the medical curriculum munich (MeCuM) reveals the need for more time for self study and higher frequency of assessment
<p>Abstract</p> <p>Background</p> <p>Seven years after implementing a new curriculum an evaluation was performed to explore possibilities for improvements.</p> <p>Purposes: To analyze students' study habits in relation to exam frequency and to evaluate effectiveness of instruction.</p> <p>Methods</p> <p>Time spent on self study (TSS) and the quantity of instruction (QI) was assessed during the internal medicine and the surgical semester. Students and faculty members were asked about study habits and their evaluation of the current curriculum.</p> <p>Results</p> <p>The TSS/QI ratio as a measure of effectiveness of instruction ranges mainly below 1.0 and rises only prior to exams. Students and teachers prefer to have multiple smaller exams over the course of the semester. Furthermore, students wish to have more time for self-guided study.</p> <p>Conclusions</p> <p>The TSS/QI ratio is predominantly below the aspired value of 1.0. Furthermore, the TSS/QI ratio is positively related to test frequency. We therefore propose a reduction of compulsory lessons and an increase in test frequency.</p
Modulation of Hepatic Amyloid Precursor Protein and Lipoprotein Receptor-Related Protein 1 by Chronic Alcohol Intake: Potential Link Between Liver Steatosis and Amyloid-ÎČ
Heavy alcohol consumption is a known risk factor for various forms of dementia and the development of Alzheimerâs disease (AD). In this work, we investigated how intragastric alcohol feeding may alter the liver-to-brain axis to induce and/or promote AD pathology. Four weeks of intragastric alcohol feeding to mice, which causes significant fatty liver (steatosis) and liver injury, caused no changes in AD pathology markers in the brain [amyloid precursor protein (APP), presenilin], except for a decrease in microglial cell number in the cortex of the brain. Interestingly, the decline in microglial numbers correlated with serum alanine transaminase (ALT) levels, suggesting a potential link between liver injury and microglial loss in the brain. Intragastric alcohol feeding significantly affected two hepatic proteins important in amyloid-beta (AÎČ) processing by the liver: 1) alcohol feeding downregulated lipoprotein receptor-related protein 1 (LRP1, âŒ46%), the major receptor in the liver that removes AÎČ from blood and peripheral organs, and 2) alcohol significantly upregulated APP (âŒ2-fold), a potentially important source of AÎČ in the periphery and brain. The decrease in hepatic LRP1 and increase in hepatic APP likely switches the liver from being a remover or low producer of AÎČ to an important source of AÎČ in the periphery, which can impact the brain. The downregulation of LRP1 and upregulation of APP in the liver was observed in the first week of intragastric alcohol feeding, and also occurred in other alcohol feeding models (NIAAA binge alcohol model and intragastric alcohol feeding to rats). Modulation of hepatic LRP1 and APP does not seem alcohol-specific, as ob/ob mice with significant steatosis also had declines in LRP1 and increases in APP expression in the liver. These findings suggest that liver steatosis rather than alcohol-induced liver injury is likely responsible for regulation of hepatic LRP1 and APP. Both obesity and alcohol intake have been linked to AD and our data suggests that liver steatosis associated with these two conditions modulates hepatic LRP1 and APP to disrupt AÎČ processing by the liver to promote AD
Mitochondrial GSH determines the toxic or therapeutic potential of superoxide scavenging in steatohepatitis
BACKGROUND & AIMS: Steatohepatitis (SH) is associated with mitochondrial dysfunction and excessive production of superoxide, which can then be converted into H(2)O(2) by SOD2. Since mitochondrial GSH (mGSH) plays a critical role in H(2)O(2) reduction, we explored the interplay between superoxide, H(2)O(2), and mGSH in nutritional and genetic models of SH, which exhibit mGSH depletion. METHODS: We used isolated mitochondria and primary hepatocytes, as well as in vivo SH models showing mGSH depletion to test the consequences of superoxide scavenging. RESULTS: In isolated mitochondria and primary hepatocytes, superoxide scavenging by SOD mimetics or purified SOD decreased superoxide and peroxynitrite generation but increased H(2)O(2) following mGSH depletion, despite mitochondrial peroxiredoxin/thioredoxin defense. Selective mGSH depletion sensitized hepatocytes to cell death induced by SOD mimetics, and this was prevented by RIP1 kinase inhibition with necrostatin-1 or GSH repletion with GSH ethyl ester (GSHee). Mice fed the methionine-choline deficient (MCD) diet or MAT1A(-/-) mice exhibited reduced SOD2 activity; in vivo treatment with SOD mimetics increased liver damage, inflammation, and fibrosis, despite a decreased superoxide and 3-nitrotyrosine immunoreactivity, effects that were ameliorated by mGSH replenishment with GSHee, but not NAC. As a proof-of-principle of the detrimental role of superoxide scavenging when mGSH was depleted transgenic mice overexpressing SOD2 exhibited enhanced susceptibility to MCD-mediated SH. CONCLUSIONS: These findings underscore a critical role for mGSH in the therapeutic potential of superoxide scavenging in SH, and suggest that the combined approach of superoxide scavenging with mGSH replenishment may be important in SH
Synergistic drug-cytokine induction of hepatocellular death as an in vitro approach for the study of inflammation-associated idiosyncratic drug hepatotoxicity
Idiosyncratic drug hepatotoxicity represents a major problem in drug development due to inadequacy of current preclinical screening assays, but recently established rodent models utilizing bacterial LPS co-administration to induce an inflammatory background have successfully reproduced idiosyncratic hepatotoxicity signatures for certain drugs. However, the low-throughput nature of these models renders them problematic for employment as preclinical screening assays. Here, we present an analogous, but high-throughput, in vitro approach in which drugs are administered to a variety of cell types (primary human and rat hepatocytes and the human HepG2 cell line) across a landscape of inflammatory contexts containing LPS and cytokines TNF, IFNÎł, IL-1α, and IL-6. Using this assay, we observed drugâcytokine hepatotoxicity synergies for multiple idiosyncratic hepatotoxicants (ranitidine, trovafloxacin, nefazodone, nimesulide, clarithromycin, and telithromycin) but not for their corresponding non-toxic control compounds (famotidine, levofloxacin, buspirone, and aspirin). A larger compendium of drugâcytokine mix hepatotoxicity data demonstrated that hepatotoxicity synergies were largely potentiated by TNF, IL-1α, and LPS within the context of multi-cytokine mixes. Then, we screened 90 drugs for cytokine synergy in human hepatocytes and found that a significantly larger fraction of the idiosyncratic hepatotoxicants (19%) synergized with a single cytokine mix than did the non-hepatotoxic drugs (3%). Finally, we used an information theoretic approach to ascertain especially informative subsets of cytokine treatments for most highly effective construction of regression models for drug- and cytokine mix-induced hepatotoxicities across these cell systems. Our results suggest that this drugâcytokine co-treatment approach could provide a useful preclinical tool for investigating inflammation-associated idiosyncratic drug hepatotoxicity.Pfizer Inc.Institute for Collaborative BiotechnologiesMIT Center for Cell Decision ProcessesNational Institute of Mental Health (U.S.) (grant P50-GM68762)National Institute of Mental Health (U.S.) (grant T32-GM008334)Massachusetts Institute of Technology. Biotechnology Process Engineering CenterMassachusetts Institute of Technology. Center for Environmental Health SciencesNational Institute of Mental Health (U.S.) (grant U19ES011399)Whitaker Foundatio
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