Interest in excitotoxicity expanded following its implication in the pathogenesis of ischemic brain injury in the 1980s, but waned subsequent to the failure of N-methyl-D-aspartate (NMDA) antagonists ...in high profile clinical stroke trials. Nonetheless there has been steady progress in elucidating underlying mechanisms. This review will outline the historical path to current understandings of excitotoxicity in the ischemic brain, and suggest that this knowledge should be leveraged now to develop neuroprotective treatments for stroke.
Summary
Background There have been conflicting data regarding the prevalence and clinicopathological characteristics of BRAF and NRAS mutations in primary cutaneous melanoma.
Objectives To solve ...this controversy, this study used a meta‐analysis to evaluate the frequencies of BRAF and NRAS mutations, and the relationship between these mutations and clinicopathological parameters of cutaneous melanoma.
Methods Data from studies published between 1989 and 2010 were combined. The BRAF and NRAS mutations were reported in 36 and 31 studies involving 2521 and 1972 patients, respectively. The effect sizes of outcome parameters were calculated by odds ratios (OR).
Results BRAF and NRAS mutations were reported in 41% and 18% of cutaneous melanomas, respectively. The mutations were associated with histological subtype and tumour site, but not with age and sex. The BRAF mutation was frequently detected in patients with superficial spreading melanoma (OR = 2·021; P < 0·001) and in melanomas arising in nonchronic sun‐damaged skin (OR = 2·043; P = 0·001). In contrast, the NRAS mutation was frequently evident in patients with nodular melanoma (OR = 1·894; P < 0·001) and in melanomas arising in chronic sun‐damaged skin (OR = 1·887; P = 0·018).
Conclusions This pooled analysis shows that the incidences of BRAF and NRAS mutations in cutaneous melanomas differ according to histological type and tumour location based on the degree of sun exposure.
MicroRNAs (miRNAs) have been shown to be major regulators of eukaryotic gene expression. However, bacterial RNAs comparable in size to eukaryotic miRNAs (18–22 nucleotides) have received little ...attention. Recently, a novel class of small RNAs similar in size to miRNAs (miRNA-size, small RNAs or msRNAs) have also been found in several bacteria. Like miRNAs, msRNAs are approximately 15 to 25 nucleotides in length, and their precursors are predicted to form a hairpin loop secondary structure. Here, we identified msRNAs in the periodontal pathogens Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola. We examined these msRNAs using a deep sequencing method and characterized dozens of msRNAs through bioinformatic analysis. Highly expressed msRNAs were selected for further validation. The findings suggest that this class of small RNAs is well conserved across the domains of life. Indeed, msRNAs secreted via bacterial outer membrane vesicles (OMVs) were detected. The ability of bacterial OMVs to deliver RNAs into eukaryotic cells was also observed. These msRNAs in OMVs allowed us to identify their potential human immune-related target genes. Furthermore, we found that exogenous msRNAs could suppress expression of certain cytokines in Jurkat T cells. We propose msRNAs may function as novel bacterial signaling molecules that mediate bacteria-to-human interactions. Furthermore, this study may provide fresh insight into bacterial pathogenic mechanisms of periodontal diseases.
Improved understanding is required on how hip fracture risk is influenced by landing configuration. We examined how hip impact dynamics was affected by hip joint kinematics during simulated sideways ...falls. Twelve young adults (7 males, 5 females) of mean age 23.5 (SD = 1.5) years, participated in pelvis release experiments. Trials were acquired with the hip flexed 15° and 30° for each of three hip rotations: +15° ("external rotation"), 0°, and -15° ("internal rotation"). During falls, force-deformation data of the pelvis were recorded. Outcome variables included the peak hip impact force (F
) and effective stiffness of the pelvis (k
, k
, and k
) determined with different methods suggested in literature, and predicted hip impact force during a fall from standing height (F
, F
and F
). The two-way repeated-measures ANOVA was used to test whether these variables were associated with hip joint angles. The F
, k
and F
were associated with hip rotation (F = 5.587, p = 0.005; F = 9.278, p < 0.0005; F = 5.778, p = 0.004, respectively), and 15 %, 31 % and 17 % smaller in 15° external than internal rotation (848 versus 998 N; 24.6 versus 35.6 kN/m; 2,637 versus 3,170 N, respectively). However, none of the outcome variables were associated with hip flexion (p > 0.05). Furthermore, there were no interactions between the hip rotation and flexion for all outcome variables (p > 0.05). Our results provide insights on hip impact dynamics, which may help improve a hip model to assess hip fracture risk during a fall.
Pregnant and postpartum women face unique challenges during the COVID-19 pandemic that may put them at elevated risk of mental health problems. However, few large-scale and no cross-national studies ...have been conducted to date that investigate modifiable pandemic-related behavioral or cognitive factors that may influence mental health in this vulnerable group. This international study sought to identify and measure the associations between pandemic-related information seeking, worries, and prevention behaviors on perinatal mental health during the COVID-19 pandemic. An anonymous, online, cross-sectional survey of pregnant and postpartum women was conducted in 64 countries between May 26, 2020 and June 13, 2020. The survey, available in twelve languages, was hosted on the Pregistry platform for COVID-19 studies (https://corona.pregistry.com) and advertised in social media channels and online parenting forums. Participants completed measures on demographics, COVID-19 exposure and worries, information seeking, COVID-19 prevention behaviors, and mental health symptoms including posttraumatic stress via the IES-6, anxiety/depression via the PHQ-4, and loneliness via the UCLA-3. Of the 6,894 participants, substantial proportions of women scored at or above the cut-offs for elevated posttraumatic stress (2,979 43%), anxiety/depression (2,138 31%, and loneliness (3,691 53%). Information seeking from any source (e.g., social media, news, talking to others) five or more times per day was associated with more than twice the odds of elevated posttraumatic stress and anxiety/depression, in adjusted models. A majority of women (86%) reported being somewhat or very worried about COVID-19. The most commonly reported worries were related to pregnancy and delivery, including family being unable to visit after delivery (59%), the baby contracting COVID-19 (59%), lack of a support person during delivery (55%), and COVID-19 causing changes to the delivery plan (41%). Greater worries related to children (i.e., inadequate childcare, their infection risk) and missing medical appointments were associated with significantly higher odds of posttraumatic stress, anxiety/depression and loneliness. Engaging in hygiene-related COVID-19 prevention behaviors (face mask-wearing, washing hands, disinfecting surfaces) were not related to mental health symptoms or loneliness. Elevated posttraumatic stress, anxiety/depression, and loneliness are highly prevalent in pregnant and postpartum women across 64 countries during the COVID-19 pandemic. Excessive information seeking and worries related to children and medical care are associated with elevated symptoms, whereas engaging in hygiene-related preventive measures were not. In addition to screening and monitoring mental health symptoms, addressing excessive information seeking and women's worries about access to medical care and their children's well-being, and developing strategies to target loneliness (e.g., online support groups) should be part of intervention efforts for perinatal women. Public health campaigns and medical care systems need to explicitly address the impact of COVID-19 related stressors on mental health in perinatal women, as prevention of viral exposure itself does not mitigate the pandemic's mental health impact.
The excellent cryogenic tensile properties of the CrMnFeCoNi alloy are generally caused by deformation twinning, which is difficult to achieve at room temperature because of insufficient stress for ...twinning. Here, we induced twinning at room temperature to improve the cryogenic tensile properties of the CrMnFeCoNi alloy. Considering grain size effects on the critical stress for twinning, twins were readily formed in the coarse microstructure by cold rolling without grain refinement by hot rolling. These twins were retained by partial recrystallization and played an important role in improving strength, allowing yield strengths approaching 1 GPa. The persistent elongation up to 46% as well as the tensile strength of 1.3 GPa are attributed to additional twinning in both recrystallized and non-recrystallization regions. Our results demonstrate that non-recrystallized grains, which are generally avoided in conventional alloys because of their deleterious effect on ductility, can be useful in achieving high-strength high-entropy alloys.
Massive open online courses (MOOCs) continue to appear across the higher education landscape, originating from many institutions in the USA and around the world. MOOCs typically have low completion ...rates, at least when compared with traditional courses, as this course delivery model is very different from traditional, fee‐based models, such as college courses. This research examined MOOC student demographic data, intended behaviours and course interactions to better understand variables that are indicative of MOOC completion. The results lead to ideas regarding how these variables can be used to support MOOC students through the application of learning analytics tools and systems.
Given the mode of transmission of Middle East respiratory syndrome (MERS), healthcare workers (HCWs) in contact with MERS patients are expected to be at risk of MERS infections. We evaluated the ...prevalence of MERS coronavirus (CoV) immunoglobulin (Ig) G in HCWs exposed to MERS patients and calculated the incidence of MERS-affected cases in HCWs. We enrolled HCWs from hospitals where confirmed MERS patients had visited. Serum was collected 4 to 6 weeks after the last contact with a confirmed MERS patient. We performed an enzyme-linked immunosorbent assay (ELISA) to screen for the presence of MERS-CoV IgG and an indirect immunofluorescence test (IIFT) to confirm MERS-CoV IgG. We used a questionnaire to collect information regarding the exposure. We calculated the incidence of MERS-affected cases by dividing the sum of PCR-confirmed and serology-confirmed cases by the number of exposed HCWs in participating hospitals. In total, 1169 HCWs in 31 hospitals had contact with 114 MERS patients, and among the HCWs, 15 were PCR-confirmed MERS cases in study hospitals. Serologic analysis was performed for 737 participants. ELISA was positive in five participants and borderline for seven. IIFT was positive for two (0.3%) of these 12 participants. Among the participants who did not use appropriate personal protective equipment (PPE), seropositivity was 0.7% (2/294) compared to 0% (0/443) in cases with appropriate PPE use. The incidence of MERS infection in HCWs was 1.5% (17/1169). The seroprevalence of MERS-CoV IgG among HCWs was higher among participants who did not use appropriate PPE.
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