Transplacental Transmission of Bluetongue Virus 8 in Cattle, UK

To determine whether transplacental transmission could explain overwintering of bluetongue virus in the United Kingdom, we studied calves born to dams naturally infected during pregnancy in 2007–08. Approximately 33% were infected transplacentally; some had compromised health. In all infected calves, viral load decreased after birth; no evidence of persistent infection was found.     

某县预防艾滋病母婴传播技术培训资源投入与利用

目的:分析某艾滋病高流行县预防母婴传播技术培训资源投入与利用情况。方法:收集研究地区2003～2006年预防艾滋病母婴传播技术培训资源投入情况,随机选取4所二级医疗机构和4所乡卫生院,收集人员培训信息,计算例均培训费用;运用χ2检验,比较培训覆盖率差异。结果:研究地区共计投入51.72万元用于预防艾滋病母婴传播技术培训,投入逐年增长,培训4571人次,县级培训人次占63.27%;例均培训费用为113.15元。二级医疗机构和乡级医疗机构培训覆盖率分别为62.77%和52.66%,二者之间差异有统计学意义。同一级别医疗机构中,不同技术类别服务提供者接受培训的比例有差异,妇产科护士受训比例最低(P<0.001)。结论:研究地区预防艾滋病母婴传播能力建设资源的投入使得能力建设覆盖面得到了扩大。     

胆碱能激动剂卡巴可对大鼠膀胱ICC样细胞内钙流的影响

目的：探讨胆碱能激动剂卡巴可对大鼠膀胱ICC样细胞钙流的影响。方法：胶原酶消化大鼠膀胱,体外培养膀胱ICC样细胞,激光共聚焦技术检测Fluo-3AM负载的ICC样细胞在卡巴可刺激下Ca^2＋信号的变化。结果：在大鼠膀胱组织铺片及体外培养细胞中观察到c-kit染色阳性及长梭形有突起的细胞鉴定为膀胱ICC样细胞;细胞给予Fluo-3AM钙负载,激光共聚焦检测,ICC细胞可观察到周期性的“钙波”;ICC样细胞受到不同浓度卡巴可刺激后,ICC样细胞自发性钙波增强。结论：ICC样细胞受刺激后自发性钙波增强,提示卡巴可可能通过ICC样细胞上的胆碱能受体兴奋ICC样细胞。     

Dynamics of event-related causality in brain electrical activity

A new method (Event-Related Causality, ERC) is proposed for the investigation of functional interactions between brain regions during cognitive processing. ERC estimates the direction, intensity, spectral content, and temporal course of brain activity propagation within a cortical network. ERC is based upon the short-time directed transfer function (SDTF), which is measured in short EEG epochs during multiple trials of a cognitive task, as well as the direct directed transfer function (dDTF), which distinguishes direct interactions between brain regions from indirect interactions via brain regions. ERC uses new statistical methods for comparing estimates of causal interactions during prestimulus "baseline" epochs and during poststimulus "activated" epochs in order to estimate event-related increases and decreases in the functional interactions between cortical network components during cognitive tasks. The utility of the ERC approach is demonstrated through its application to human electrocorticographic recordings (ECoG) of a simple language task. ERC analyses of these ECoG recordings reveal frequency-dependent interactions, particularly in high gamma (>60 Hz) frequencies, between brain regions known to participate in the recorded language task, and the temporal evolution of these interactions is consistent with the putative processing stages of this task. The method may be a useful tool for investigating the dynamics of causal interactions between various brain regions during cognitive task performance.     

Dopamine spillover after quantal release: rethinking dopamine transmission in the nigrostriatal pathway

The predominance of dopamine (DA) receptors at extrasynaptic vs. synaptic sites implies that DA signaling is by diffusion-based volume transmission. In this review, we compare characteristics that regulate extracellular DA behavior in substantia nigra pars compacta (SNc) and striatum, including regional differences in structure (a 40% greater extracellular volume fraction in SNc vs. striatum) and in dynamic DA uptake (a 200-fold greater DA uptake rate in striatum vs. SNc). Furthermore, we test the assumption of diffusion-based volume transmission for SNc and striatum by modeling dynamic DA behavior after quantal release using region-specific parameters for diffusion and uptake at 37 degrees C. Our model shows that DA uptake does not affect peak DA concentration within 1 mum of a release site in either SNc or striatum because of the slow kinetics of DATs vs. diffusion. Rather, diffusion and dilution are the dominant factors governing DA concentration after quantal release. In SNc, limited DAT efficacy is reflected in a lack of influence of uptake on either amplitude or time course of DA transients after quantal release up to 10 mum from a release site. In striatum, the lack of effect of the DAT within 1 mum of a release site means that perisynaptic DATs do not "gate" synaptic spillover. This contrasts with the conventional view of DA synapses, in which DATs efficiently recycle DA by re-uptake into the releasing axon terminal. However, the model also shows that a primary effect of striatal uptake is to curtail DA lifetime after release. In both SNc and striatum, effective DA radius after quantal release is ~2 mum for activation of low-affinity DA receptors and 7-8 mum for high-affinity receptors; the corresponding spheres of influence would encompass tens to thousands of synapses. Thus, the primary mode of intercellular communication by DA, regardless of region, is volume transmission.     

Transfer of ureteral carcinoma in a transplanted kidney presenting by early stenosis of the proximal ureter

A 71-yr-old male kidney transplant recipient suffered from delayed graft function. Eighty days after transplantation complete obstruction of the proximal ureter was observed, complicated by recurrent urinary tract infections. Two months later, the donor kidney was removed because of infectious complications and inadequate arterial perfusion. Histological examination of the removed graft showed signs of rejection as well as a low-grade papillary urothelial cell carcinoma of donor origin in the ureter. The remaining donor ureter was removed subsequently and showed no further signs of malignancy. Follow-up of the patient until 12 months after surgery did not reveal recurrence of the tumor. This case report is the first to describe accidental transfer of urothelial cell carcinoma in the ureter by transplantation, highlighting the possibility of malignancy when early stenosis is not related to the anastomosis. It again emphasizes the need for precise and cautious screening of organ donors, especially those of higher age.     

Pathway-dependent modulation by P2-purinoceptors in the mouse retina

Adenosine trisphosphate (ATP) activates purinoceptors and acts as a neurotransmitter in the nervous system. In the retina, we previously reported that the immunohistochemical distribution of the subset of P2-purinoceptors differs between the ON and OFF pathways. Here, we investigated whether ATP activates P2-purinoceptors and modulates the physiological function of the mouse retina. We also examined if signal processing by P2-purinoceptors is pathway specific. Results showed that ATP activated both ON- and OFF-cholinergic amacrine cells. However, responses in OFF-cholinergic amacrine cells were greater than those in ON-cholinergic amacrine cells. Pharmacological studies in OFF-cholinergic amacrine cells showed that the response of OFF-cholinergic amacrine cells is mediated P2X₂-purinoceptors. Further, ATP increased γ-aminobutyric acid (GABA)ergic inhibitory postsynaptic currents (IPSCs) in OFF- but not ON-cholinergic amacrine cells. The increase in GABAergic IPSCs was mediated by P2-purinoceptors. P2-purinoceptor-mediated signals suppressed OFF ganglion cells but activated ON ganglion cells. Our findings indicate that ATP physiologically modulates signal processing of the ON and OFF pathways in a pathway-specific manner through P2-purinoceptors.     

John Eccles (1903–97) and the experiment that proved chemical synaptic transmission in the central nervous system

One of the most important experiments in neurophysiology in the twentieth century took place in the physiology laboratories at the University of Otago, New Zealand, in August 1951. The group of researchers led by John Eccles convincingly established that synaptic transmission in the central nervous system was a chemical process. This work was the culmination of a long debate between advocates of electrical and chemical transmission. The conclusions overturned Eccles's previous theories of an electrical "Golgi-cell" mechanism and represent a pivotal moment in the history of neuroscience.