Lower Brainstem Pathways Regulating Sympathetically Mediated Changes in Cutaneous Blood Flow

1. When the individual is alerted by painful or salient stimuli, there is a vigorous sympathetically mediated constriction of the cutaneous vascular bed. We investigated central pathways mediating this response using chronically implanted Doppler ultrasonic probes to measure cutaneous blood flow in the rabbit ear pinna and in the rat tail.2. Blockade of neuronal function in the amygdala prevents cutaneous vasoconstriction elicited by salient stimuli, but does not prevent the response to painful stimuli. Blockade of neuronal function in raphe magnus/pallidus and the parapyramidal region in anesthetized rabbits prevents cutaneous vasoconstriction elicited by painful stimuli. A similar region of the medullary raphe regulates tail artery vasoconstriction in rats. Inhibition of neuronal function in this region reverses cutaneous vasoconstriction induced by cooling the animal.3. Bulbospinal presympathetic neurons in the rostral medullary raphe region appear to regulate cutaneous blood flow responses occurring as part of the response to painful or dangerous environmental events and as part of the regulation of body temperature.     

Effects of the Activity of the Internal Globus Pallidus-Pedunculopontine Loop on the Transmission of the Subthalamic Nucleus-External Globus Pallidus-Pacemaker Oscillatory Activities to the Cortex

Resting tremor is the most specific sign for idiopathic Parkinson' disease. It has been proposed that parkinsonian tremor results from the activity of the central oscillators. One of the hypotheses, which have been proposed about the possible principles underlying such central oscillations, is the subthalamic nucleus (STN)-external globus pallidus (GPe)-pacemaker hypothesis. Activity from the central oscillator is proposed to be transmitted via trans-cortical pathways to the periphery. A computational model of the basal ganglia (BG) is proposed for simulating the effects of the internal globus pallidus (GPi)-pedunculopontine (PPN) loop activity on the transmission of the STN-GPe-pacemaker oscillatory activities to the cortex, based on known anatomy and physiology of the BG. According to the result of the simulation, the GPi-PPN loop activity can suppress the transmission of the STN-GPe-pacemaker oscillatory activities to the cortex. This suppressive effect is controlled by various factors such as the strength of the synaptic connection from the PPN to the GPi, the strength of the synaptic connection from the GPi to the PPN, the spontaneous tonic activities of the GPi and PPN, the direct excitatory projections from the STN to the PPN, the frequency of the STN oscillatory burst activity, the duration of the STN burst, and the maximum T-type calcium channel conductance in the type-I PPN neurons.     

Convergent evidence from microdialysis and presynaptic immunolabeling for the regulation of gamma-aminobutyric acid release in the globus pallidus following acute clozapine or haloperidol administration in rats

Antipsychotic drugs (APDs) have been primarily characterized for their effects on dopaminergic terminal regions in the brain, especially within the corpus striatum. Efferent GABA pathways are the primary outflow of striatal processing via their projections to the substantia nigra and the globus pallidus (GP). In the current study, we analyzed changes in pallidal GABA function following acute APD administration by means of in vivo microdialysis, followed by immunolabeling of presynaptic GABA terminal density in the contralateral hemisphere of the same animals. Acute administration of the atypical APD, clozapine (10 or 30 mg/kg, s.c.), produced a dose-dependent decrease in extracellular GABA. A corresponding dose-dependent increase in the density of presynaptic terminal GABA immunolabeling in the GP was found. In contrast, the typical APD, haloperidol (1 or 3 mg/kg, s.c.), had no significant effects on either measure, although a non-significant increase in extracellular GABA and decrease in the density of GABA terminal immunolabeling was noted. Paw retraction tests conducted during the time of microdialysis showed that haloperidol produced a typical pattern of highly pronounced motor impairment, while clozapine showed an atypical profile of minimal catalepsy. These complementary results obtained from in vivo neurochemistry and presynaptic neurotransmitter labeling suggest that systemic clozapine suppresses neuronal GABA release within the GP. This decrease in released pallidal GABA may play a role in the low motor side-effect liability of atypical APDs.     

HIV associated dementia and HIV encephalitis II: Genes on chromosome 22 expressed in individually microdissected Globus pallidus neurons (Preliminary analysis)

We analyzed RNA gene expression in neurons from 16 cases in four categories, HIV associated dementia with HIV encephalitis (HAD/HIVE), HAD alone, HIVE alone, and HIV-1-positive (HIV+)with neither HAD nor HIVE. We produced the neurons by laser capture microdissection (LCM) from cryopreserved globus pallidus. Of 55,000 gene fragments analyzed, expression of 197 genes was identified with significance (p = 0.005).We examined each gene for its position in the human genome and found a non-stochastic occurrence for only seven genes, on chromosome 22. Six of the seven genes were identified, CSNK1E (casein kinase 1 epsilon), DGCR8 (Di George syndrome critical region 8), GGA1 (Golgi associated gamma adaptin ear containing ARF binding protein 1), MAPK11 (mitogen activated protein kinase 11), SMCR7L (Smith-Magenis syndrome chromosome region candidate 7-like), andTBC1D22A (TBC1 domain family member 22A). Six genes (CSNK1E, DGCR8, GGA1, MAPK11, SMCR7L, and one unidentified gene) had similar expression profiles across HAD/HIVE, HAD, and HIVE vs. HIV+ whereas one gene (TBC1D22A) had a differing gene expression profile across these patient categories. There are several mental disease-related genes including miRNAs on chromosome 22 and two of the genes (DGCR8 and SMCR7L) identified here are mental disease-related. We speculate that dysregulation of gene expression may occur through mechanisms involving chromatin damage and remodeling. We conclude that the pathogenesis of NeuroAIDS involves dysregulation of expression of mental disease-related genes on chromosome 22 as well as additional genes on other chromosomes. The involvement of these genes as well as miRNA requires additional investigation since numerous genes appear to be involved.     

How two different host species influence the performance of a gregarious parasitoid: host size is not equal to host quality

1. Hyssopus pallidus Askew (Hymenoptera, Eulophidae) is a gregarious ectoparasitoid of the two tortricid moths species Cydia molesta Busck and C. pomonella L. (Lepidoptera, Tortricidae). It paralyses and parasitizes different larval instars of both species inside the apple fruit, which leads to the death of the caterpillar. 2. We assessed the influence of host species characteristics and host food on the performance of the parasitoid female in terms of clutch size decisions and fitness of the F(1) generation. 3. A comparison of clutch size revealed that female parasitoids deposited similar numbers of eggs on the comparatively smaller C. molesta hosts as on the larger C. pomonella hosts. The number of parasitoid offspring produced per weight unit of host larva was significantly higher in C. molesta than in C. pomonella, which is contrary to the general prediction that smaller hosts yield less parasitoid offspring. However, the sex ratio was not influenced by host species that differed considerably in size. 4. Despite the fact that less host resources were available per parasitoid larva feeding on C. molesta caterpillars, the mean weight of emerging female wasps was higher in the parasitoids reared on C. molesta. Furthermore, longevity of these female wasps was neither influenced by host species nor by the food their host had consumed. In addition we did not find a positive relationship between adult female weight and longevity. 5. Parasitoid females proved to be able to assess accurately the nutritional quality of an encountered host and adjust clutch size accordingly. These findings indicate that host size is not equal to host quality. Thus host size is not the only parameter to explain the nutritional quality of a given host and to predict fitness gain in the subsequent generation.     

The theoretical mechanism of Parkinson’s oscillation frequency bands: a computational model study

Excessive synchronous oscillation activities appear in the brain is a key pathological feature of Parkinson’s disease, the mechanism of which is still unclear. Although some previous studies indicated that β oscillation (13–30 Hz) may directly originate in the network composed of the subthalamic nucleus (STN) and external globus pallidus (GPe) neurons, specific onset mechanisms of which are unclear, especially theoretical evidences in numerical simulation are still little. In this paper, we employ a STN–GPe mean-field model to explore the onset mechanism of Parkinson’s oscillation. In addition to β oscillation, we find that some other common oscillation frequency bands can appear in this network, such as the α oscillation band (8–12 Hz), the θ oscillation band (4–7 Hz) and δ oscillation band (1–3 Hz). In addition to the coupling weight between the STN and GPe, the delay is also a critical factor to affect oscillatory activities, which can not be neglected compared to other parameters. Through simulation and analysis, we propose two possible theories may induce the system to transfer from the stable state to the oscillatory state in this model: (1). The oscillation activity can be induced when the firing activation level of the population increases to large enough; (2). In some special cases, the population may stay in the high firing rate stable state and the mean discharge rate of which is too large to induce oscillations, then oscillation activities may be induced as the MD decreases to moderate value. In most situations, the change trends of the MD and oscillation dominant frequency are contrary, which may be an important physiological phenomenon shown in this model. The delays and firing rates were obtained by simulating, which may be verified in the experiment in the future.     

Characterization and emulsifying property of a novel bioemulsifier by Aeribacillus pallidus YM-1

Aims: Biosurfactants and bioemulsifiers commonly have the advantages of biodegradability, low toxicity, selectivity and biocompatibility over chemically synthesized surfactants. The goal of the study is to present a novel bioemulsifier with great application potential. Methods and Results: Aeribacillus pallidus YM‐1, isolated from crude oil contaminated soil, was found to produce a novel high molecular bioemulsifier with an emulsification index of 60 ± 1% without remarkable surface tension reduction (45·7 ± 0·1 mN m^?1). The number‐average molecular weight was determined as 526 369 Da by gel permeation chromatography analysis. Bioemulsifier was subjected to FT‐IR and a complex of carbohydrates (41·1%), lipids (47·6%) and proteins (11·3%) was determined. Conclusions: The bioemulsifier of A. pallidus YM‐1 was isolated from the glucose‐based culture medium and characterized with the help of chemical analytical techniques. The bioemulsifier exhibited a promising emulsifying property for biotechnology application potential in bioremediation and microbial enhanced oil recovery. Significance and Impact of the Study: This is the first report of the bioemulsifier production by A. pallidus. The potential emulsifying activity of the bioemulsifier in the present study may be explored in various biotechnological and industrial applications.     

苍白球电毁损对帕金森病大鼠HVSs 振荡波的影响研究

目的:应用直流电核团毁损术毁损帕金森病(PD)大鼠模型的内侧苍白球(GPi),记录其手术前后脑电生理活动的变化,以探讨内苍白球射频毁损术治疗PD的可能机制。方法:成年SD大鼠随机分为GP毁损组、假手术组及正常组。对PD毁损组和假手术组大鼠采用6-羟基多巴胺(6-OHDA)右侧黑质致密部(SNc)、中脑腹侧被盖区(VTA)两点注射法建立PD大鼠模型,并经腹腔注射阿扑吗啡(APO)诱发旋转以对模型建立进行评价。通过多导联宏电极在体脑电生理记录技术对各组大鼠进行右侧(注射侧)大脑皮层M1、M2区脑电及纹状体场电位的连续24小时记录,同时进行视频录像。对GP毁损组大鼠行直流电GPi毁损术,术后4天对各组大鼠均行阿扑吗啡诱导旋转行为检验,继续记录脑电活动,记录数据经频率谱分析及相干分析以揭示各记录位点信号的频率成分以及不同位点神经元集群间的功能连接和同步性。结果:对GP毁损组大鼠毁损术前后在清醒静息状态下的皮层脑电和纹状体场电位有明显改变,术后HVSs(High Voltage Spindles)在持续时间上明显缩短发作次数明显减少;对各组大鼠术后在静息状态下的脑电信号进行对比,GP毁损组大鼠较假手术组的HVSs持续时间和发作频率均减少并接近正常组大鼠水平,相干性分析显示GP毁损组大鼠术后在HVSs频段(5-13Hz)上的相干程度显著小于假手术组。结论:在清醒静息状态下6-OHDA建立的PD大鼠皮层-基底节环路上HVSs持续时间延长发生频率增高,经GP毁损术后其时间缩短发作次数减少同步性降低并接近正常水平,从而改善PD症状,该现象可能解释临床采用苍白球射频毁损术治疗PD的治疗机制。     

基于网格的医学信息平台设计

针对目前医学信息应用模式的局限性,提出一种基于网格的平台技术,促进网络环境下的医学资源共享和互用。其中采用面向网格工具包的中间件设计,简化了服务集成和调用。实验模型的建立验证平台的可行性及实用价值。     

Comparative life history and parasitism of a new colour morph of the walnut aphid in California

1 The walnut aphid Chromaphis juglandicola is a yellow aphid. In 2003, however, a white colour morph was discovered in the Sacramento Valley of California. The colour dimorphism occurs between clone lines and, when white morphs are present, they occur in mixed colour morph colonies on the underside of walnut leaves. 2 Laboratory experiments were undertaken to evaluate the thermal requirements for development, adult longevity and progeny production of the two colour morphs. Host instar preference of Trioxys pallidus, a parasitoid responsible for the successful biological control of the walnut aphid in California, was examined separately for each colour morph, and host colour preference was investigated for the preferred instar. 3 No differences in thermal requirements for development, adult size or mean longevity were detected between yellow and white colour morphs. A small difference in early reproduction was detected: white colour morphs produced more progeny on each of the two first days of adult reproduction than yellow colour morphs. 4 Trioxys pallidus showed a slight preference for the fourth instar of the yellow morph over the second‐ and third‐, but equal preference for second, third and fourth instars of the white morph. When offered equal numbers of fourth instars of the two colour morphs, T. pallidus did not show any colour preference. 5 The differences in early aphid reproduction and host instar preference by T. pallidus were combined in a stage‐structured matrix model. Model analysis showed a greater potential for population growth of the white morph over the yellow morph, with early reproduction having a greater influence than host instar preference.