Intercellular communication in the rat anterior pituitary gland: an in vivo and in vitro study

The concept of "stimulus-secretion coupling" suggested by Douglas and co-workers to explain the events related to monamine discharge by the adrenal medulla (5, 7) may be applied to other endocrine tissues, such as adrenal cortex (36), pancreatic islets (4), and magnocellular hypothalamic neurons (6), which exhibit a similar ion-dependent process of hormone elaboration. In addition, they share another feature, that of joining neighbor cells via membrane junctions (12, 26, and Fletcher, unpublished observation). Given this, and the reports that hormone secretion by the pars distalis also involves a secretagogue-induced decrease in membrane bioelectric potential accompanied by a rise in cellular [Ca++] (27, 34, 41), it was appropriate to test the possibility that cells of the anterior pituitary gland are united by junctions.     

Natural products as starting points for future anti-malarial therapies: going back to our roots?

Background

Population movements along the Thailand-Cambodia border, particularly among highly mobile and hard-to-access migrant groups from Cambodia and Myanmar, are assumed to play a key role in the spread of artemisinin resistance. Data on treatment-seeking behaviours, knowledge and perceptions about malaria, and use of preventive measures is lacking as characteristics of this population prevent them from being represented in routine surveillance and the lack of a sampling frame makes reliable surveys challenging.

Methods

A survey of migrant populations from Cambodia and Myanmar was implemented in five selected rural locations in Thailand along the Thai-Cambodian border using respondent driven sampling (RDS) to determine demographic characteristics of the population, migratory patterns, knowledge about malaria, and health-care -seeking behaviours.

Results

The majority of migrants from Myanmar are long-term residents (98%) with no plans to move back to Myanmar, understand spoken Thai (77%) and can therefore benefit from health messages in Thai, have Thai health insurance (99%) and accessed public health services in Thailand (63%) for their last illness. In comparison, the majority of Cambodian migrants are short-term (72%). Of the short-term Cambodian migrants, 92% work in agriculture, 18% speak Thai, 3.4% have Thai health insurance, and the majority returned to Cambodia for treatment (45%), self-treated (11%), or did not seek treatment for their last illness (27%).

Conclusion

Most highly mobile migrants along the Thai-Cambodia border are not accessing health messages or health treatment in Thailand, increasing their risk of malaria and facilitating the spread of potentially resistant Plasmodium falciparum as they return to Cambodia to seek treatment. Reaching out to highly mobile migrants with health messaging they can understand and malaria diagnosis and treatment services they can access is imperative in the effort to contain the spread of artemisinin-resistant P. falciparum.     

Airway cellularity, lipid laden macrophages and microbiology of gastric juice and airways in children with reflux oesophagitis

Background and methods

Human metapneumovirus (hMPV) is a recently discovered respiratory virus associated with bronchiolitis, pneumonia, croup and exacerbations of asthma. Since respiratory viruses are frequently detected in patients with acute exacerbations of COPD (AE-COPD) it was our aim to investigate the frequency of hMPV detection in a prospective cohort of hospitalized patients with AE-COPD compared to patients with stable COPD and to smokers without by means of quantitative real-time RT-PCR.

Results

We analysed nasal lavage and induced sputum of 130 patients with AE-COPD, 65 patients with stable COPD and 34 smokers without COPD. HMPV was detected in 3/130 (2.3%) AE-COPD patients with a mean of 6.5 × 10⁵ viral copies/ml in nasal lavage and 1.88 × 10⁵ viral copies/ml in induced sputum. It was not found in patients with stable COPD or smokers without COPD.

Conclusion

HMPV is only found in a very small number of patients with AE-COPD. However it should be considered as a further possible viral trigger of AE-COPD because asymptomatic carriage is unlikely.     

The ecological relevance of sleep: the trade-off between sleep,memory and energy conservation

All animals in which sleep has been studied express signs of sleep-like behaviour, suggesting that sleep must have some fundamental functions that are sustained by natural selection. Those functions, however, are still not clear. Here, we examine the ecological relevance of sleep from the perspective of behavioural trade-offs that might affect fitness. Specifically, we highlight the advantage of using food-caching animals as a system in which a conflict might occur between engaging in sleep for memory/learning and hypothermia/torpor to conserve energy. We briefly review the evidence for the importance of sleep for memory, the importance of memory for food-caching animals and the conflicts that might occur between sleep and energy conservation in these animals. We suggest that the food-caching paradigm represents a naturalistic and experimentally practical system that provides the opportunity for a new direction in sleep research that will expand our understanding of sleep, especially within the context of ecological and evolutionary processes.     

Transmission routes of Salmonella Typhimurium DT 104 between 14 cattle and pig herds in Denmark demonstrated by molecular fingerprinting

AIMS: Salmonella Typhimurium DT 104 is generally assumed to be spread by contact between live animals, e.g. by trading. The aim of the present study was to assess the importance of other routes of transmission in the dissemination of this bacterium. METHODS AND RESULTS: An outbreak among 14 cattle and pig herds located in a geographically narrow area in Denmark was investigated. Epidemiological information and disease history of the herds was obtained through interviews. Based on this, the hypothesis for horizontal spread was proposed, and these were confirmed by comparison of the pulsed field gel electrophoresis (PFGE) and the plasmid profiles of isolates obtained by continuous sampling over a period of almost 3 years. CONCLUSIONS: The study indicated that other routes might play an important role, than the trading of live animals, in the spread of S. Typhimurium DT 104 among livestock. SIGNIFICANCE AND IMPACT OF THE STUDY: Salmonella Typhimurium DT 104 infected herd might pose a significant risk to herds located within the same geographic area. In advising on how to avoid the spread of this bacterium, factors like person contacts, sharing of equipment and contaminated slurry should be focussed on in addition to infected animals.     

Developmental neurobiology: awakening the brain for the first time

Imaging of the chicken embryo in the egg has revealed that the entire brain can be switched on for the first time earlier than expected by exposure to maternal vocalizations.     

植物的遗传转化及其应用(英文)

近年来,植物遗传转化研究有了长足的发展。已经达到能够通过简单的遗传控制手段研究具有新表现型的植物,甚至达到进入商业化的程度。这些手段包括植物生物学的主要研究技术以及植物组织培养和树种改良的一些实用方法。尽管采用农瘤杆菌和鸟枪法等技术的植物遗传转化系统已经得到了广泛的应用,但是在如何开发具有能够得到控制表达的转基因高产植物方面,在如何使所得到的转基因植物远离遗传危害等方面,目前的转化系统遇到了极大的技术挑战。已经提出了各种各样的方法用于将新基因稳定地导入120多种不同植物的核基因组。本文将讨论这些遗传转化系统所需的生物学要求和实际应用方面的需求、基因转化和转基因表达的研究策略、遗传转化植物的鉴定以及转基因植物与大众的认可。本文将分为七个部分加以讨论:一、导言;二 、基因转化到细胞里的方法;三、植物遗传转化策略;四、植物遗传转化的鉴定;五、植物遗传转化的实际应用;六、转基因植物与环境;七、未来植物遗传转化的需求与发展方向。     

Sleep and vigilance linked to melanism in wild barn owls

Understanding the function of variation in sleep requires studies in the natural ecological conditions in which sleep evolved. Sleep has an impact on individual performance and hence may integrate the costs and benefits of investing in processes that are sensitive to sleep, such as immunity or coping with stress. Because dark and pale melanic animals differentially regulate energy homeostasis, immunity and stress hormone levels, the amount and/or organization of sleep may covary with melanin‐based colour. We show here that wild, cross‐fostered nestling barn owls (Tyto alba) born from mothers displaying more black spots had shorter non‐REM (rapid eye movement) sleep bouts, a shorter latency until the occurrence of REM sleep after a bout of wakefulness and more wakefulness bouts. In male nestlings, the same sleep traits also correlated with their own level of spotting. Because heavily spotted male nestlings and the offspring of heavily spotted biological mothers switched sleep–wakefulness states more frequently, we propose the hypothesis that they could be also behaviourally more vigilant. Accordingly, nestlings from mothers displaying many black spots looked more often towards the nest entrance where their parents bring food and towards their sibling against whom they compete. Owlets from heavily spotted mothers might invest more in vigilance, thereby possibly increasing associated costs due to sleep fragmentation. We conclude that different strategies of the regulation of brain activity have evolved and are correlated with melanin‐based coloration.     

Properties of microtubule sliding disintegration in isolated tetrahymena cilia

Properties of the sliding disintegration response of demembranated tetrahymena cilia have been studied by measuring the spectrophotomeric response or turbidity of cilia suspensions at a wavelength of 350 nm relative to changes in the dynein substrate (MgATP(2-)) concentration. The maximum decrease in turbidity occurs in 20 muM ATP, and 90 percent of the decrease occurs in approximately 5.9 s. At lower ATP concentrations (1-20 muM), both the velocity and magnitude of the turbidity decreases are proportional to ATP concentration. The velocity data for 20 muM ATP permit construction of a reaction velocity curve suggesting that changes in turbidity are directly proportional to the extent and velocity of disintegration. At ATP concentrations more than 20 muM (50muM to 5mM), both velocity and magnitude of the turbidimetric response are reduced by approximately 50 percent. This apparent inhibition results in a biphasic response curve that may be related to activation of residual shear resistance or regulatory components at the higher ATP concentrations. The inhibitory effects of elevated ATP can be eliminated by mild trypsin proteolysis, whereupon the reaction goes to completion at any ATP concentration. The turbidimetric responses of the axoneme-substrate suspensions are consistent with the extent and type of axoneme disintegration revealed by electron microscope examination of the various suspensions, suggesting that the turbidimetric assay may prove to be a reliable means for assessing the state of axoneme integrity.