LHRH-A对孕中期大鼠抗妊娠作用的研究

本文观察了[D-Ala⁶,Pro⁹-Ethylamide¹⁰]-LHRH(LHRH-A)对孕中期大鼠的抗妊娠作用。结果显示:在孕9～11d sc 200μg/d LHRH-A,血浆孕酮水平自第二次给药后明显下降(P<0.05),给药大鼠均流产终止妊娠;LHRH-A的抗妊娠作用可被醋酸甲地孕酮所拮抗;LHRH-A对体外培养的假孕大鼠和孕d 9大鼠黄体细胞分泌孕酮有明显的直接抑制作用。     

GGA1 acts as a spatial switch altering amyloid precursor protein trafficking and processing

The beta-amyloid (Abeta) precursor protein (APP) is cleaved sequentially by beta-site of APP-cleaving enzyme (BACE) and gamma-secretase to release the Abeta peptides that accumulate in plaques in Alzheimer's disease (AD). GGA1, a member of the Golgi-localized gamma-ear-containing ARF-binding (GGA) protein family, interacts with BACE and influences its subcellular distribution. We now report that overexpression of GGA1 in cells increased the APP C-terminal fragment resulting from beta-cleavage but surprisingly reduced Abeta. GGA1 confined APP to the Golgi, in which fluorescence resonance energy transfer analyses suggest that the proteins come into close proximity. GGA1 blunted only APP but not notch intracellular domain release. These results suggest that GGA1 prevented APP beta-cleavage products from becoming substrates for gamma-secretase. Direct binding of GGA1 to BACE was not required for these effects, but the integrity of the GAT (GGA1 and TOM) domain of GGA1 was. GGA1 may act as a specific spatial switch influencing APP trafficking and processing, so that APP-GGA1 interactions may have pathophysiological relevance in AD.     

Evaluation and audit in a paediatric disability service

Parental and professional responses to questionnaires evaluating a paediatric disability service are reported and the viability of auditing structural, process, and outcome aspects of clinical practice are discussed. Expectations of waiting time to first appointment (met for only 52% of consumers) illustrate structural issues. Process issues are reflected in consumer reactions to outreach work (for example, 94% of parents and 84% of professionals found this supportive). Outcome measures such as consumer satisfaction with the service (76% of consumers reported being 'very satisfied' and 20% 'fairly satisfied') suggest that service aims are being met. Good concurrence of service aims with consumer needs is indicated by parental reasons for referral (for example, 75% for diagnostic help, 73% for a better understanding of the disorder, 88% for practical help), referrers' reasons (for example, 55% for a second diagnostic opinion, 45% due to lack of local expertise), and reports from most other professionals involved with the case that a similar service was not provided locally.     

总粉尘浓度转换为呼吸性粉尘浓度的两种方法学研究

目的探讨流行病学研究中历史性总粉尘浓度转换成呼吸性粉尘浓度的理论方法。方法采用两种方法：一种通过体积直接计算;另一种用ＨａｔｃｈＣｈｏａｔｅ方程计算,推导出计数百分比和计量百分比的转换关系。结果得到总粉尘浓度与呼吸性粉尘浓度的理论转换系数,其中,用ＨａｔｃｈＣｈｏａｔｅ方程计算结果偏低。结论体积直接计算法更适用。     

Behaviour and physiological responses during prone and supine sleep in early infancy

AIMS: To study the effect of prone and supine sleep on infant behaviour, peripheral skin temperature, and cardiorespiratory parameters to aid understanding of why prone sleeping is associated with an increased risk of sudden infant death syndrome. METHODS: Of 33 enrolled infants, 32 were studied at 2.5 and 28 at 5 months of age. A computer aided multichannel system was used for polysomnographic recordings. Behaviour was charted separately. RESULTS: Prone REM (active) sleep was associated with lower frequencies of short arousals, body movements and sighs, and a shorter duration of apnoeas than supine REM sleep at both ages. At 2.5 months there were less frequent episodes of periodic breathing during prone sleep in non-REM (quiet) and REM sleep. Heart rate and peripheral skin temperature were higher in the prone position during both sleep states at both ages. CONCLUSIONS: The observation of decreased variation in behaviour and respiratory pattern, increased heart rate, and increased peripheral skin temperature during prone compared with supine sleep may indicate that young infants are less able to maintain adequate respiratory and metabolic homoeostasis during prone sleep.     

发育期缺铁性贫血对大鼠空间学习能力和海马树突结构的影响

本研究旨在判断贫血过程中,中等程度发展的缺铁性贫血(IDA)对婴儿活动性和海马形态的影响,以及对早期恢复过程中空间学习的影响。一、材料与方法1．实验设计：30只雌性SD怀孕大鼠随机分为铁正常(IS)组和铁缺乏(ID)组,每组15只。IS组大鼠在怀孕期和子鼠出生后摄入铁充足饮食(40～50mg铁/kg体重)。     

Structure and interactions in covalently and ionically crosslinked chitosan hydrogels for biomedical applications.

This review presents a critical analysis of covalently and ionically crosslinked chitosan hydrogels and related networks for medical or pharmaceutical applications. The structural basis of these hydrogels is discussed with reference to the specific chemical interactions, which dictate gel formation. The synthesis and chemistry of these hydrogels is discussed using specific pharmaceutical examples. Covalent crosslinking leads to formation of hydrogels with a permanent network structure, since irreversible chemical links are formed. This type of linkage allows absorption of water and/or bioactive compounds without dissolution and permits drug release by diffusion. pH-controlled drug delivery is made possible by the addition of another polymer. Ionically crosslinked hydrogels are generally considered as biocompatible and well-tolerated. Their non-permanent network is formed by reversible links. Ionically crosslinked chitosan hydrogels exhibit a higher swelling sensitivity to pH changes compared to covalently crosslinked chitosan hydrogels. This extends their potential application, since dissolution can occur in extreme acidic or basic pH conditions.     

Augmentative and Alternative Communication (AAC) for adults with severe aphasia: where we stand and how we can go further

Purpose: To review literature specific to the use of AAC with adults who have severe aphasia. Method: The authors reviewed studies involving AAC interventions for adults with severe aphasia. Results: Published data support the use of aided and unaided AAC with adults with severe aphasia in controlled treatment contexts. Reported gains in communication typically have not generalized to everyday settings. Conclusions: The application of AAC with persons with severe aphasia must address factors potentially limiting treatment success outside of training environments.     

Someone to talk to: the association of mentorship and cyberbullying with suicidality among US high school students

Objective

Suicide is the second-leading cause of death in youth. We tested whether having a mentoring relationship associated with lower risks for suicidality, particularly among youth at higher risk due to cyberbullying.

Methods

This study pooled the 2017 Youth Risk Behavior Survey (YRBS) data from five jurisdictions that asked students if there was at least one teacher or other adult in their school that they could talk with, if they have a problem (mentorship). Students self-reported cyberbullying exposure and suicidality in the past 12 months. Odds of suicidal ideation, planning, and attempts were estimated using multivariable weighted logistic regression in overall and sex-stratified stepwise models. Interactions between mentorship and cyberbullying were also tested.

Results

Of the 25,527 student respondents, 87% reported having a mentoring relationship. Mentoring relationships were associated with lower odds of suicidal ideation (aOR, 0.44; 95% CI 0.33–0.57), planning (aOR, 0.59; 95% CI 0.41–0.85), and suicide attempts (aOR, 0.42; 95% CI 0.31–0.56). Stratified analyses showed a significant interaction between cyberbullying and mentorship with suicidal attempts among males, and a near-significant association between cyberbullying and mentorship with suicidal thoughts among females. Compared to male students with no cyberbullying and no mentorship, odds of attempting suicide were lower for males with no cyberbullying and mentorship (aOR, 0.55, 95% CI 0.32–0.92), higher for males with cyberbullying and no mentorship (aOR, 7.78, 95% CI 3.47–17.47), but not significantly different for males with cyberbullying and mentoring relationships (aOR, 1.49, 95% CI 0.86–2.48). Similarly, compared with females with no cyberbullying and no mentorship, odds of having suicidal thoughts were lower for females with no cyberbullying and mentorship (aOR, 0.40, 95% CI 0.28–0.57), and higher for females with cyberbullying and no mentorship (aOR, 2.54, 95% CI 1.59–4.07).

Conclusion

School-based mentoring may mitigate risk of suicidality among adolescents and limit the toxic effects of cyberbullying.