Differential release of histamine and prostaglandin D2 in rat peritoneal mast cells: roles of cytosolic calcium and protein tyrosine kinases

AbstractWe studied how the release of histamine and prostaglandin D2 (PGD2) were connected in stimulated rat peritoneal mast cells, and to what extent these processes were controlled by the cytosolic Ca2+ concentration, [Ca2+]i, and protein tyrosine kinases. In the presence of 1 mM CaCl2, the G-protein activating compound 48/80 (10 μg/ml) evoked a transient rise in [Ca2+]i and a relatively high secretion of histamine, but only a low release of PGD2. In contrast, 5 μM thapsigargin (an inhibitor of endomembrane Ca2+-ATPases) and 5 μM ionomycin evoked high and prolonged rises in [Ca2+]i, and stimulated the cells to release relatively small amounts of histamine and high amounts of PGD2. Stimulation of the cells with CaCl2 and 10 μM ATP4− gave only minor quantities of histamine and PGD2, despite of the micromolar level of [Ca+]i reached. When CaCl2 was replaced by EGTA, rises in [Ca2+]i as well as release of histamine and PGD2 were reduced with each agonist, but the preference of agonists to release more histamine or PGD2 remained unchanged. In mast cells with depleted Ca2+ stores, the addition of CaCl2 stimulated the store-regulated Ca2+ entry resulting in a prolonged rise in [Ca2+]i. However, simultaneous addition of compound 48/80 and CaCl2 was required for release of histamine and PGD2. In cells with full stores, PGD2 release evoked by compound 48/80 was greatly reduced by genistein and methyl-2,5-dihydroxycinnamate, two structurally unrelated inhibitors of protein tyrosine kinases, whereas histamine secretion was not influenced by these inhibitors. Similarly, with thapsigargin or ionomycin as agonist, PGD2 release was more sensitive to the tyrosine kinase inhibitors than histamine secretion. We conclude that in activated rat peritoneal mast cells: (i) the influx of extracellular Ca2+ potentiates agonist-evoked rises in [Ca2+]i as well as histamine secretion and PGD2 release; (ii) the amplitude of the [Ca2+]i rise does not determine the preferential effect of agonists to release more histamine or more PGD2; (iii) the relatively high PGD2 release evoked by thapsigargin and ionomycin is probably due to their potency to evoke a prolonged rise in [Ca2+]i and to activate protein tyrosine kinases

Adolescents' peer status profiles and differences in school engagement and loneliness trajectories:A person-centered approach

This study used a person-centered approach to identify adolescents' peer status profiles and examined how these profiles differed regarding the development of school engagement and loneliness. A sample of 794 adolescents was followed from Grades 7 to 11 (M-ageWave1 = 13.81 years). Measures included peer nominations of peer status, and student reports of school engagement and peer-related loneliness. Latent class growth analysis identified three profiles: popular-liked, unpopular-disliked, and normative. The popular-liked class revealed the lowest levels of behavioral engagement and loneliness. The unpopular-disliked class had higher levels of behavioral engagement, less steep increases in behavioral disaffection, and showed more loneliness. The normative class revealed moderate trajectories of engagement and loneliness. Moreover, boys and girls differed in their academic and psychosocial development. Implications of the findings for school practitioners are discussed

The role of alcohol specific socialization in adolescents’ drinking behavior.

ABSTRACT Aims To determine which alcohol-specific socialization practices are related to adolescents' alcohol use, and to investigate whether parents differ in their alcohol-specific socialization towards their children. Design In a sample of 428 families, both parents and two adolescents (aged 13-16 years) completed a questionnaire at home about alcohol-specific parenting and their own alcohol use. Based on the reports of each family member, three different models of alcohol-specific socialization were formulated: from the perspective of the siblings, the mother and the father. Findings Results of structural equation modelling generally showed the same associations between alcohol-specific socialization and drinking of younger and older adolescents. The strongest association was found for providing alcoholspecific rules. Applying strict rules about alcohol use was negatively related to adolescents' alcohol use; this was also the case for having confidence in the effectiveness of alcohol-specific socialization. Unexpectedly, frequency of communication about alcohol issues was positively associated with alcohol consumption of adolescents. Conclusions This study is one of the first to examine associations between alcohol-specific socialization and adolescents' drinking using a between-and a within-family design. Results showed strong associations between alcoholspecific socialization (particularly of enforcing rules) and adolescent alcohol use. Although parents strongly differentiated their socialization practices between children, no differences in associations between alcohol-specific socialization and drinking were found between older and younger adolescents

Synchronous vegetation response to the last glacial-interglacial transition in northwest Europe

The North Atlantic region experienced abrupt high-amplitude cooling at the onset of the Younger Dryas stadial. However, due to chronological uncertainties in the available terrestrial records it is unclear whether terrestrial ecosystem response to this event was instantaneous and spatially synchronous, or whether regional or time-transgressive lags existed. Here we use new palynological results from a robustly dated lake sediment sequence retrieved from lake Hämelsee (north Germany) to show that vegetation change started at 12,820 cal. yr BP, concurrent with the onset of changes in local climate. A comparison of the Hämelsee results to a compilation of precisely dated palynological records shows instant and, within decadal-scale dating uncertainty, synchronous response of the terrestrial plant community to Late-Glacial climate change across northwest Europe. The results indicate that the environmental impact of climate cooling was more severe than previously thought and illustrates the sensitivity of natural terrestrial ecosystems to external forcing. © 2022, The Author(s)

Keeping secrets from parents: Advantages and disadvantages of secrecy in adolescence.

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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216