Circadian Variation in Circulating Platelet Aggregates

The mitochondrial F₁F_o adenosine triphosphate (ATP) synthase is one of the most thoroughly studied enzyme complexes known. Yet, a number of new observations suggesting that the enzyme is also located on the cell surface necessitate further investigation. While the mitochondrial synthase utilizes the proton gradient generated by oxidative phosphorylation to power ATP synthesis, the cell surface synthase has instead been implicated in numerous activities, including the mediation of intracellular pH, cellular response to antiangiogenic agents, and cholesterol homeostasis. Intriguingly, a common thread uniting these various models of cell surface ATP synthase functions is the apparently caveolar distribution of the enzyme. Recent studies concerning the cell surface ATP synthase manifest applications in the regulation of serum cholesterol levels, cellular proliferation and antitumor strategies. This review addresses the expression, interactions, functions, and consequences of inhibition of cell surface ATP synthase, an enzyme now displaying a shift in paradigm, as well as of location.     

Prion疾病疫苗研究策略

朊病毒病是一类侵袭人类及多种动物中枢神经系统的致死性退行性脑病,目前缺乏有效的预防和治疗方法.朊病毒病的重组蛋白亚单位疫苗、DNA疫苗、合成肽疫苗、病毒样颗粒疫苗、树突状细胞疫苗、黏膜免疫疫苗等已取得一定进展,但现有的免疫策略仅能部分克服免疫耐受,诱导较低或中等滴度的抗体,对PrPSc感染动物模型只能提供部分保护,Prion疫苗研究任重而道远.     

Cloning and characterization of voltage‐gated calcium channel alpha1 subunits in Xenopus laevis during development

Voltage‐gated calcium channels play a critical role in regulating the Ca²⁺ activity that mediates many aspects of neural development, including neural induction, neurotransmitter phenotype specification, and neurite outgrowth. Using Xenopus laevis embryos, we describe the spatial and temporal expression patterns during development of the 10 pore‐forming alpha1 subunits that define the channels' kinetic properties. In situ hybridization indicates that Ca_V1.2, Ca_V2.1, Ca_V2.2, and Ca_V3.2 are expressed during neurula stages throughout the neural tube. These, along with Ca_V1.3 and Ca_V2.3, beginning at early tail bud stages, and Ca_V3.1 at late tail bud stages, are detected in complex patterns within the brain and spinal cord through swimming tadpole stages. Additional expression of various alpha1 subunits was observed in the cranial ganglia, retina, olfactory epithelium, pineal gland, and heart. The unique expression patterns for the different alpha1 subunits suggests they are under precise spatial and temporal regulation and are serving specific functions during embryonic development. Developmental Dynamics 238:2891–2902, 2009. © 2009 Wiley‐Liss, Inc.     

百日咳杆菌毒素S1亚单位突变体的研究进展

百日咳杆菌毒素(PT)是目前无细胞百日咳疫苗中的主要保护性成分,其中PT的S1亚单位又是其主要的功能性亚基,具有免疫保护活性和多种毒性。在对多个S1突变体的生物学及免疫学研究后发现,其中的一个S1的双位点突变体(PTX-9K/129G)在保持有良好的免疫原性和免疫保护作用的基础上,大大降低了PT的毒性,有望成为理想的百日咳疫苗候补抗原。     

β-HCG、孕酮及子宫内膜厚度诊断早期异位妊娠的价值

目的探讨早期异位妊娠诊断的方法,提高诊断准确性。方法对95例疑似异位妊娠的患者测定血清β-HCG、孕酮值及测量子宫内膜厚度。结果异位妊娠组β-HCG、孕酮值及子宫内膜厚度明显低于正常宫内妊娠组和异常宫内妊娠组(P均<0.01),三项指标联合应用可将诊断准确性提高至93.68%。结论血清β-HCG及孕酮值是确定妊娠的指标,但难以鉴别异位妊娠和尚未形成宫内孕囊的早期宫内妊娠及流产,结合子宫内膜厚度则能提高异位妊娠的准确性,可成为具有临床应用价值的早期诊断异位妊娠的指标。     

核苷酸还原酶亚单位M1和内切修复交叉补体1在非小细胞肺癌中的研究进展

核苷酸还原酶亚单位M1（RRM1）属抑癌基因，RRM1可以激发G2期检测点功能，使受损的DNA得以修复或者发生凋亡，并具有抑制细胞侵袭和转移的作用，另外RRM1还可以调节核苷酸还原酶的活性，是抗代谢药吉西他滨作用的靶分子，RRM1高表达的细胞对吉西他滨耐药。内切修复交叉补体1（ERCC1）是细胞内负责修复受损DNA的核苷酸内切修复通路中的限速酶，可以识别和去除铂-DNA附加物而导致细胞对铂类耐药。本文综述RRM1和ERCC1在非小细胞肺癌患者预后和化疗个体化方面的研究进展。     

Evidence against cholera toxin B subunit as a reliable tracer for sprouting of primary afferents following peripheral nerve injury

In order to investigate whether cholera toxin B subunit (CTb) is transported by unmyelinated primary afferents following nerve injury, we transected the sciatic nerves of six rats, and injected the transected nerves (and in three cases also the intact contralateral nerves) with CTb, 2 weeks later. The relationship between CTb and two neuropeptides, vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY), was then examined in neurons in the ipsilateral L4 and L5 dorsal root ganglia, using immunofluorescence staining and confocal microscopy. We also immunostained sections of spinal cord and caudal medulla for CTb, NPY and VIP. Following nerve section, VIP immunoreactivity was increased in laminae I-II of the spinal cord while NPY immunoreactivity was increased in laminae III-IV of the spinal cord and in the gracile nucleus. On the contralateral side, CTb labelling was detected in laminae I and III-V of the dorsal horn of the L4 and L5 spinal segments, as well as in the gracile nucleus. CTb labelling was seen in the same areas on the lesioned side, but with a dramatic increase in lamina II. No VIP or NPY immunoreactivity was observed in L4 and L5 dorsal root ganglia on the side of the intact nerve, but on the lesioned side VIP was detected in many small neurons and NPY in numerous large neurons. In agreement with the report by Tong et al. [J. Comp. Neurol. 404 (1999) 143], we found that while CTb labelling in the dorsal root ganglion on the side of the intact nerve was mainly in large neurons, on the lesioned side CTb was present in dorsal root ganglion neurons of all sizes. The main finding of the present study was that almost all of the VIP- (96%) and NPY- (98%) positive neurons in the dorsal root ganglia on the lesioned side were also CTb-labelled. After nerve injury VIP is upregulated in fine afferents that terminate in laminae I and II, and most of these probably have unmyelinated axons. Since the cell bodies of these neurons were labelled with CTb that had been injected into the transected sciatic nerve, this suggests that many of these fine afferents, which do not normally transport CTb, are capable of doing so after injury.     

Diffuse perineuronal nets and modified pyramidal cells immunoreactive for glutamate and the GABA(A) receptor alpha1 subunit form a unique entity in rat cerebral cortex

Perineuronal nets (PNs) consisting of polyanionic chondroitin sulfate proteoglycans (CSPG) and other extracellular matrix components create an exceptional microenvironment around certain types of neurons. In rat neocortex, three types of PNs can be distinguished after staining with Wisteria floribunda agglutinin (WFA) by their different morphological structure: lattice-like PNs associated with subpopulations of nonpyramidal neurons, weakly labeled PNs showing a pyramidal morphology, and diffuse PNs that possess a thick, strongly labeled matrix sheath located mainly in layer VIb above the white matter. The type of neuron surrounded by diffuse nets has not been described so far. This study is focused on the cytochemical and morphological characteristics of neurons associated with diffusely contoured PNs in rat parietal cortex using immunocytochemical staining, intracellular injection, and retrograde tracing methods. Cells surrounded by diffuse PNs were glutamate-immunoreactive in contrast to nonpyramidal, net-associated neurons that showed immunoreactivity for GABA, the calcium-binding protein parvalbumin and the potassium channel subunit Kv3.1b. Both groups of PN-ensheathed cells were mostly immunoreactive for the GABA(A) receptor alpha1 subunit. Lucifer Yellow-injected neurons surrounded by diffuse PNs displayed the morphological properties of modified pyramidal cells with intracortical main axons. Many neurons with diffuse PNs were retrogradely labeled over a long distance after Fluoro-Gold tracer injection in the parietal cortex, but remained unlabeled after intrathalamic injection. We conclude that neurons associated with diffuse PNs are a subpopulation of glutamatergic modified pyramidal cells that could act as excitatory long-range intracortically projecting neurons.     

Repeated cocaine administration differentially affects NMDA receptor subunit (NR1, NR2A-C) mRNAs in rat brain

We investigated the effects of intermittent intraperitoneal (i.p.) injections of cocaine (20 mg/kg) on subunit mRNAs of N-methyl-D-aspartate (NMDA) receptors (NR1/NR2A-2C) in the rat brain by in situ hybridization using phosphor screen analysis. The level of NR1 subunit mRNA significantly increased in hippocampal complexes 1 h after a single i.p. injection of cocaine. After repeated cocaine injection, the mean scores of stereotyped behavior were increased with the number of injections. The level of NR1 subunit mRNA was obviously decreased in the striatum and cortices 24 h (early withdrawal) after a final injection following 14 days of subchronic administration. During the early withdrawal period, the amount of the NR1 subunit decreased in the nucleus accumbens, globus pallidus, and subiculum. In the dentate gyrus, the NR1 mRNA level significantly increased during early withdrawal in rats subchronically treated with cocaine. Levels of NR2B subunit mRNA were reduced in the cortices and striatum. During late withdrawal from cocaine, the level of NR2C subunit mRNA in the cerebellum was also reduced. These findings suggest that the disruption of NR1, NR2B, and NR2C subunits in the discrete brain regions occurs under the cocaine-related behavioral abnormalities and would be closely implicated in the initiation and expression of behavioral sensitization induced by repeated cocaine administration. Further studies on the changes in non-NMDA receptors are required to elucidate the biological significance of glutamate receptors for the mechanisms underlying the development of behavioral sensitization.