P2X receptors in trigeminal subnucleus caudalis modulate central sensitization in trigeminal subnucleus oralis

This study investigated the role of trigeminal subnucleus caudalis (Vc) P2X receptors in the mediation of central sensitization induced in nociceptive neurons in subnucleus oralis (Vo) by mustard oil (MO) application to the tooth pulp in anesthetized rats. MO application produced a long-lasting central sensitization reflected in neuroplastic changes (i.e., increases in neuronal mechanoreceptive field size and responses to innocuous and noxious mechanical stimuli) in Vo nociceptive neurons. Twenty minutes after MO application, the intrathecal (i.t.) administration to the rostral Vc of the selective P2X(1), P2X(3), and P2X(2/3) receptor antagonist, 2'-(or 3'-)O-trinitrophenyl-ATP (TNP-ATP), significantly and reversibly attenuated the MO-induced central sensitization for more than 15 min; saline administration had no effect. Administration to the rostral Vc of the selective P2X(1), P2X(3), and P2X(2/3) receptor agonist, alpha,beta-methylene ATP (alpha,beta-meATP, i.t.) produced abrupt and significant neuroplastic changes in Vo nociceptive neurons, followed by neuronal desensitization as evidenced by the ineffectiveness of a second i.t. application of alpha,beta-meATP and subsequent MO application to the pulp. Administration to the rostral Vc of the selective P2X(1) receptor agonist beta,gamma-methylene ATP (beta,gamma-meATP, i.t.) produced no significant neuroplastic changes per se and did not affect the subsequent MO-induced neuroplastic changes in Vo nociceptive neurons. These results suggest that P2X(3) and possibly also the P2X(2/3) receptor subtypes in Vc may play a role in the initiation and maintenance of central sensitization in Vo nociceptive neurons induced by MO application to the pulp.     

耳穴静态电测量中的瞬变响应

耳穴电参数时变关系实验表明，在测量起始ｔ＜２τ时，因瞬变作用，电位Ｅ（ｔ）和压降Ｕ（ｔ）为瞬态响应，响应函数呈指数关系，特征参数为弛豫时间τ，τ≈ＲＣ；ｔ＞２τ时，为时变间期。电路分析给出数学描述，并与耳穴和模拟实验结果较相符。提示，时变特征应以ｔ＞２τ后提取，静态电测量时，采样应避开瞬变期，可提高准确性。该工作对正确鉴别时变性和特征提取，全面认识耳穴电特性具有重要意义。     

Class II defective avian sarcoma viruses: Comparative analysis of genome structure

The genomes of class II avian sarcoma viruses PRCII, PRCII-p, PRCIV, and Fujinami sarcoma virus (FSV), were studied by oligonucleotide fingerprinting, heteroduplex mapping, and nucleic acid hybridization. All of these viruses are genetically defective and have a small RNA genome between 4.5 and 6.1 kilobases (kb) in length. They contain helper-related sequences at both the 5′- and 3′-ends, but most of the retroviral sequences in the middle of the genome are deleted. In place of this deleted information, a contiguous stretch of transformation-specific sequences, termed fps, is found. These putative oncogenic sequences are about 1.2 kb in PRCII, and those in PRCII-p and PRCIV are roughly 2.9 kb. From the analysis of oligonucleotides, it appears that the fps sequences of PRCII represent a subset of those of PRCII-p. Most of the additional sequences present in PRCII-p but absent from PRCII are at the 5′-half of fps. The helper-related sequences in PRCII and PRCII-p are almost indistinguishable, except that PRCII-p contains slightly more retroviral information at the 3′-end of the genome. Therefore, it is possible that PRCII has been derived by deletion from PRCII-p. By contrast, PRCII-p and PRCIV were found to contain identical fps sequences, but their helper-related sequences have diverged substantially. These two sarcoma viruses either represent two independent isolates or, if derived from a single isolate, they have undergone extensive mutation and recombination with diverse avian retroviruses. FSV was found to differ to a greater extent from other class II sarcoma viruses in both helper-related and fps sequences. The difference in fps sequences is localized in the 5′-half of that region. Considering the variation in fps among all members of class II avian sarcoma viruses, it appears that the 3′-half of that genetic region is more conserved than the 5′-half.     

Effects of temporomandibular joint stimulation on nociceptive and nonnociceptive neurons of the cat's trigeminal subnucleus caudalis (medullary dorsal horn)

1. The extracellular activity of 196 single neurons in subnucleus caudalis (medullary dorsal horn) of the trigeminal (V) spinal tract nucleus was examined in chloralose-anesthesized, paralyzed cats. Electrical, mechanical, and algesic chemical stimuli were applied to the exposed temporomandibular joint (TMJ) in order to activate TMJ afferents. Seventy-eight neurons were studied that responded to electrical stimulation of the TMJ at a mean latency of 9.9 +/- 4.8 (SD) ms. 2. All neurons with TMJ input received additional afferent input, predominantly from facial skin or intraoral sites. Caudalis neurons were classified on the basis of their cutaneous mechanoreceptive field properties as low-threshold mechanoreceptive (LTM), wide dynamic range (WDR), or nociceptive specific (NS); a few neurons unresponsive to cutaneous stimuli were responsive to manipulation of deep subcutaneous structures. A sample of caudalis neurons was tested for responsiveness to electrical TMJ stimulation after the mechanoreceptive field properties of the neurons were determined. In this sample, 24% of the LTM neurons, 29% of the WDR neurons, 36% of the NS neurons, and 57% of the neurons with input from deep structures were responsive to TMJ stimulation. The WDR and NS neurons with TMJ inputs had mechanoreceptive field properties and laminar locations in caudalis that were comparable to those previously described for cutaneous nociceptive neurons in caudalis; also in accordance with recent studies, 74% of the neurons tested showed convergence of tooth pulp and/or hypoglossal (XII) nerve afferent inputs. 3. In contrast to the LTM neurons, the WDR and NS neurons were especially responsive to intense mechanical and algesic chemical stimulation of the TMJ as well as to electrical stimulation of TMJ afferents. For example, 71% of the WDR and NS neurons excited by electrical stimulation of the TMJ afferents and tested for their responsiveness to injections of algesic chemicals (7% NaCl, KCl, bradykinin, histamine) into the TMJ responded to at least one of these chemicals. The temporal characteristics of these responses were quantified. 4. The TMJ afferent inputs to the WDR and NS neurons were considered to be predominantly of a nociceptive character because of (1) the long latency and high threshold of most TMJ-evoked responses, which are consistent with previous demonstrations that small-diameter afferents predominantly supply the TMJ and, (2) the preferential responsiveness to noxious mechanical and chemical stimulation of TMJ afferents of neurons which were functionally identified as cutaneous nociceptive neurons.(ABSTRACT TRUNCATED AT 400 WORDS)     

Age-associated alterations in CXCL1 chemokine expression by murine B cells

Background  

The CXCL1 chemokines, macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC), have been shown to play a role in a number of pathophysiological disease states including endotoxin-induced inflammation and bacterial meningitis. While the expression of these chemokines has been identified in a variety of cell types in the mouse, little is known about their expression with murine B-lymphocytes.     

甲襞、球结膜微循环的应急观测方法

甲襞、球结膜微循环的应急观测方法是在甲襞、球结膜微循环加权积分综合定量评价方法的基础上，保留权值为４、３的指标，同时观察血管清晰度和红细胞聚集二项指标而形成。同时提供其应急观测积分表、异常分度积分值、诊断标准，并与常规方法进行比较，证明其可以反映绝大部分流态类指标和大部分形态类指标及重要的袢周改变，没有丢失微循环重度异常的信息，保证了重度异常诊断的正确。但在大致正常、轻度异常和中度异常的诊断中应急方法部有判重的倾向，说明应急方法漏掉了一些信息，不能全面地了解微循环的改变，造成了判重的倾向。因此应急方法不能代替常规方法，只能在特定条件下应用。     

5一羟色胺能神经对横断损伤脊髓的再支配-脊髓内移植研究

用成年SD大鼠20只在脊髓的低位胸髓完全横断损伤,分别在1周和1月后,用富含5一羟色胺(5—HT)神经元的胚鼠脑干中缝组织悬液植人损伤尾侧的脊髓内,动物存活2个月,脊髓作5—HT免疫组化观察.结果:(1)胚5-HT能神经元能在成年大鼠脊髓内存活,5-HT纤维大多在灰质中延伸并向靶区分布,(2)损伤后1周移植组的5-HT能神经元存活量,5-HT纤维在宿主脊髓内延伸距离,以及5-HT末梢再分布的密度都优于损伤后1月移植组.     

Evaluation of United States-licensed human immunodeficiency virus immunoassays for detection of group M viral variants

Six Food and Drug Administration (FDA)-licensed human immunodeficiency virus type 1 (HIV-1) and HIV-1/2 immunoassays, including five enzyme immunoassays and one rapid test, were challenged with up to 250 serum samples collected from various global sites. The serum samples were from individuals known to be infected with variants of HIV-1 including group M subtypes A, B, B', C, D, E, F, and G and group O. All immunoassays detected the vast majority of samples tested. Three samples produced low signal over cutoff values in one or more tests: a clade B sample, an untypeable sample with a low antibody titer, and a group O sample. It is concluded that HIV-1 immunoassays used in the United States are capable of detecting most HIV-1 group M variants.