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Despite recommendations from the World Health Organization and the American Academy of Pediatrics to exclusively breastfeed infants for their first 6 months of life, 75% of women do not meet exclusive breastfeeding guidelines, and 60% do not meet their own breastfeeding goals. Numerous observational studies have linked maternal psychological distress (eg, perceived stress, anxiety, and depression) with nonoptimal breastfeeding outcomes, such as decreased proportion and duration of exclusive breastfeeding. The physiological mechanisms underlying these associations, however, remain unclear. For this narrative review, we evaluated the evidence of relationships between maternal psychological distress and lactation and breastfeeding outcomes in pregnancy and post partum and the possible physiological mechanisms that facilitate these relationships. We searched PubMed using the following terms: stress, anxiety, depression, breastfeeding, and lactation. Additional search by hand was conducted to ensure a thorough review of the literature. Among the studies examined, methods used to assess maternal psychological distress were not uniform, with some studies examining perceived distress via a variety of validated tools and others measuring biological measures of distress, such as cortisol. Evidence supports a role for psychological distress in multiple breastfeeding outcomes, including delayed secretory activation and decreased duration of exclusive breastfeeding. One physiological mechanism proposed to explain these relationships is that psychological distress may impair the release of oxytocin, a hormone that plays a critical role in milk ejection during lactation. Continued impairment of milk ejection may lead to decreased milk production because of incomplete emptying of the breast during each feed. Maternal distress may also yield elevated levels of serum cortisol and decreased insulin sensitivity, which are associated with decreased milk production. The relationship between psychological distress and breastfeeding is likely to be bidirectional, however, in that breastfeeding appears to reduce maternal distress, again possibly via effects on the pleasure or reward pathway and calming effects of oxytocin on the mother. This finding suggests that interventions to support lactation and breastfeeding goals in women who score high on measures of psychological distress would be beneficial for both maternal and infant well-being. Evidence to date suggests that maternal psychological distress may impair lactation and breastfeeding outcomes, but stronger study designs and rigorous assessment methods are needed. A better understanding of the physiological mechanisms leading to impaired lactation may assist in the development of early interventions for mothers experiencing distress. In addition, stress-reducing programs and policies should be investigated for their potential to improve breastfeeding outcomes.

To examine how household food insecurity is related to adolescent weight status and disordered eating. Cross-sectional, population-based study. Adolescents self-reported unhealthy weight control behaviours, binge eating and meal frequency; weight status was measured. Household food insecurity was assessed by asking parents to respond to the validated six-item US Household Food Security Survey Module. Adolescents surveyed within Minneapolis/St. Paul public middle and high schools completed surveys at school, and their parents/guardians were surveyed by mail during the 2009-2010 academic year. Ethnically/racially diverse, primarily low-income adolescents (mean age: 14·4 years, range: 10-22 years) and their parents/guardians (n 2285 dyads). More than one-third (38·9 %) of the adolescents experienced past-year household food insecurity, 43·2 % reported disordered eating and 39·6 % were overweight. Generalised regression models showed that food insecure (FI) compared with food secure (FS) adolescents had higher prevalence of overweight (FI: 42·3 % v. FS: 37·9 %, P = 0·039), lower breakfast consumption (FI: 4·1 times/week v. FS: 4·4 times/week, P = 0·005) and greater use of unhealthy weight control behaviours (FI: 49·0 % v. FS: 39·5 %, P < 0·001) in unadjusted models. Models adjusted for parental education, ethnicity/race, sex and age found that food insecurity was associated with higher prevalence of unhealthy weight control behaviours (FI: 44·5 % v. FS: 37·8 %, P = 0·007), but not with weight status or other eating behaviours. These results suggest that food insecurity may be an independent risk factor for unhealthy weight control behaviours, indicating a need to approach these intersecting issues in a comprehensive manner.

Firearm-Related Deaths among Black Rural YouthsMortality among young persons has risen, with firearm-related deaths disproportionately affecting Black youths. Firearm-related deaths now affect Black youths across both rural and urban settings.

كتاب (علم الأحياء- بيتر هـ. ريفن وآخرون) : هو المرجع الأول لهذا الاختصاص باللغة العربية، الجدير بالذكر : إن هذا الكتاب يتميز بالشرح الوافي بالصور الواضحة ويصل عدد صفحاته إلى ما يزيد عن 1500 صفحه والتي تتحدث عن ثمانية أبواب : الأول عن الأساس الجزيئي للحياة والثاني علم حياة الخلية، بينما يفصل الباب الثالث الوراثة وعلم الحياة الجزيئي والجزء الرابع التطور ويأتي تنوع الحياة على الأرض في الباب الخامس، بينما ينفرد السادس بأشكال النباتات ووظائفها، أما الباب السابع فيتناول أشكال الحيوانات ووظائفها ويختتم الكتاب أبوابه مع علم البيئة والسلوك.

Analysis of publicly available genomic and gene expression data demonstrates that MCL1 expression is frequently elevated in breast cancer. Distinct from other pro-survival Bcl-2 family members, the short half-life of MCL-1 protein led us to investigate MCL-1 protein expression in a breast cancer tissue microarray and correlate this with clinical data. Here, we report associations between high MCL-1 and poor prognosis in specific subtypes of breast cancer including triple-negative breast cancer, an aggressive form that lacks targeted treatment options. Deletion of MCL-1 in the mammary epithelium of genetically engineered mice revealed an absolute requirement for MCL-1 in breast tumorigenesis. The clinical applicability of these findings was tested through a combination of approaches including knock-down or inhibition of MCL-1 to show triple-negative breast cancer cell line dependence on MCL-1 in vitro and in vivo . Our data demonstrate that high MCL-1 protein expression is associated with poor outcome in breast cancer and support the therapeutic targeting of MCL-1 in this disease.

The authors show that p53 helps cancer cells survive serine depletion by coordinating metabolic remodelling; a diet lacking serine slowed tumour growth in mice, with p53-null tumours showing greatest sensitivity to serine starvation. Serine deprivation as anticancer mechanism The tumour suppressor p53 functions in a number of stress-response pathways. Karen Vousden and colleagues now report that p53 also helps cancer cells to survive conditions of serine depletion by limiting proliferation and channeling serine metabolism to glutathione production and reactive oxygen species limitation. Cells that lack p53 fail to undergo these adaptations and are much more vulnerable to serine depletion. These findings were exploited to demonstrate that a diet lacking serine can reduce the growth of p53-deficient tumours in a mouse model. This work suggests that serine depletion — by removal from the diet, enzymatic depletion or some other means — is worthy of further investigation as a possible therapeutic approach. Cancer cells acquire distinct metabolic adaptations to survive stress associated with tumour growth and to satisfy the anabolic demands of proliferation. The tumour suppressor protein p53 (also known as TP53) influences a range of cellular metabolic processes, including glycolysis 1 , 2 , oxidative phosphorylation 3 , glutaminolysis 4 , 5 and anti-oxidant response 6 . In contrast to its role in promoting apoptosis during DNA-damaging stress, p53 can promote cell survival during metabolic stress 7 , a function that may contribute not only to tumour suppression but also to non-cancer-associated functions of p53 8 . Here we show that human cancer cells rapidly use exogenous serine and that serine deprivation triggered activation of the serine synthesis pathway and rapidly suppressed aerobic glycolysis, resulting in an increased flux to the tricarboxylic acid cycle. Transient p53-p21 (also known as CDKN1A) activation and cell-cycle arrest promoted cell survival by efficiently channelling depleted serine stores to glutathione synthesis, thus preserving cellular anti-oxidant capacity. Cells lacking p53 failed to complete the response to serine depletion, resulting in oxidative stress, reduced viability and severely impaired proliferation. The role of p53 in supporting cancer cell proliferation under serine starvation was translated to an in vivo model, indicating that serine depletion has a potential role in the treatment of p53-deficient tumours.

Low childhood socio-economic status (SES) and adverse childhood experiences (ACE) are associated with poor health outcomes in adulthood. Determining how ACE may be linked to food insecurity among young people from socio-economically diverse households can inform health-protective strategies. This study examined if ACE are associated with food insecurity during the transition to adulthood and investigated prevalence differences across SES strata. Participants were recruited from twenty secondary schools in Minneapolis-St. Paul, Minnesota. The analytic sample ( 1518) completed classroom surveys in 2009-2010 (mean age = 14·5 years) and follow-up surveys in 2017-2018 (mean age = 22·0 years). Past-year food insecurity was reported at both time points, and ACE were reported at follow-up. Logistic regression models were used to estimate emerging adult food insecurity prevalence by ACE exposure; models were stratified by childhood SES (low, middle and high). The adjusted prevalence of food insecurity was 45·3 % among emerging adults who reported three or more ACE compared with 23·6 % among those with one or two ACE and 15·5 % among those with no ACE ( < 0·001). All forms of ACE were related to an elevated prevalence of food insecurity in emerging adulthood. ACE-food insecurity associations were strongest for emerging adults from lower and middle SES households. Among emerging adults from low SES households, childhood experiences of emotional abuse and substance use by a household member were associated with the largest prevalence differences in food insecurity. Findings suggest a need for trauma-informed services within food assistance programs to better serve individuals with a history of ACE.