Pax-1 in the development of the cervico-occipital transitional zone

The Pax-1 gene has been found to play an important role in the development of the vertebral column. The cervico-occipital transitional zone is a specialized region of the vertebral column, and malformations of this region have frequently been described in humans. The exact embryonic border between head and trunk is a matter of controversy. In order to determine a possible role of Pax-1 in the development of the cervico-occipital transitional zone we studied the expression of this gene in a series of quail embryos and murine fetuses with in situ hybridization and immunohistochemistry. Pax-1 is expressed in all somites of the embryo, including the first five occipital ones. During embryonic days 3–5 the gene is down-regulated in the caudal direction within the first five somites, whereas more caudally Pax-1 is strongly expressed in the cells of the perinotochordal tube. In 5-day-old quail embryos, the cartilaginous anlage of the basioccipital bone has developed and there is no more expression of Pax-1 in this region. The fusion of the dens axis with the body of the axis also coincides with switching off of the Pax-1 gene. More caudally, the gene is continuously expressed in the intervertebral discs of murine embryos and therefore seems to be important for the process of resegmentation. Quail embryos do not possess permanent intervertebral discs. Hyper- or hyposegmentation defects may be explained by an over- or under-expression of Pax-1 during development. We also reinvestigated the border between the head and trunk in chick embryos by performing homotopical grafting experiments of the 5^th somite between chick and quail embryos. Grafted quail cells formed mainly the caudal end of the basioccipital bone. They were also located in the cranial half of the ventral atlantic arch, and only a few cells were found in the tip of the dens axis.     

Effects of coexisting neurochemicals on the release of serotonin from the intermediate area of rat thoracic spinal cord

Serotonin (5-HT), substance P (SP), neurokinin A (NKA), and thyrotropin-releasing hormone (TRH) coexist in the nerve terminals of the intermediolateral cell column (IML) of the thoracic spinal cord. The Ca2⁺-dependent release of 5-HT from the microdissected intermediate area (including the IML) of the rat thoracic spinal cord, and the 5-HT_1B autoreceptor regulator of 5-HT release, were previously demonstrated. In this paper, the effects of SP, NKA, TRH, and/or their analogs on the release of [³H]5-HT from the intermediate area were investigated using an in vitro superfusion system. Both SP (the endogenous ligand for neurokinin-1 (NK₁) receptor) and an NK₁, agonist (GR 73632) significantly increased the basal release of [³3H]5-HT. SP and GR 73632 did not change the K⁺-stimulated release of [³H]5-HT. The effect of the NK₁ agonist on the basal release of [³H]5-HT was dose-dependent, was reduced by an NK₁ antagonist (GR 82334), and was not dependent on extracellular Ca²⁺. Neither NKA, an NK₂, agonist (GR 64349), nor a TRH analog (MK-771) altered the basal or stimulated release of [³H]5-HT. These data suggest that basal release of 5-HT from the intermediate area of the rat thoracic spinal cord is regulated by SP (acting through an NK₁ receptor), but not by NKA or TRH. These results provide evidence for the role of SP as a modulator of serotoninergic neurons in the intermediate area of the thoracic spinal cord, and may help to clarify the role of coexisting neurochemicals in the spinal regulation of the sympathetic nervous system. © 1995 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Flow-mediated cell stress induction in adherent leukocytes is accompanied by modulation of morphology and phagocytic function

Leukocytes adherent to the surfaces of both vascular biomaterials and normal blood vessels experience blood flow induced shear stress. The goal of the reported studies was to investigate the effect of fluid flow on the morphology, phagocytic function and stress response induction in adherent immune cells. Shear approximating arterial, venous and intermediate levels were applied onto glass-adherent IC21 macrophages in a temperature-controlled parallel plate flow system. The results indicate that fluid flow induces a shear-dependent physiological stress response in adherent macrophages and that significant morphological changes accompany macrophage responses to shear stress. In addition, arterial flow conditions induce not only significant cell polarisation, but also enhanced phagocytic ingestion in glass-adherent IC21 macrophages. These findings suggest that blood flow induced shear stress may not only be consequent to adherent leukocyte activation, but may also be integral to the regulation of adherent leukocyte behaviour in vivo.     

（S）—（一）—α—苯乙胺萃取过程的研究

提出采用萃取法回收苯乙胺的工艺方案,考察了多种萃取剂的萃取性能,确定了氯仿作萃取剂的操作条件。根据实验和计算表明本方案苯乙胺的萃取收率可达９７％以上,苯乙胺的总回收率可达８７％以上。     

Excitability of spinal cord and gracile nucleus neurons in rats with chronically injured sciatic nerve examined by c-fos expression

Low-threshold sensory pathways have been suggested to have an important role in the formation and maintenance of sensory abnormalities which are observed after peripheral nerve injury. Fos-like immunoreactive (Fos-LI) neurons are expressed in spinal cord laminae III-IV and the gracile nucleus by electrically stimulating the injured nerves at Abeta strength after sciatic nerve transection in rats. This suggests that the excitability of these neurons is increased by nerve injury. In this study, we investigated which receptors are involved in the regulation of the increased excitability in spinal and gracile nucleus neurons. The sciatic nerve of Sprague-Dawley rats (150 g) was transected 7 days before the experiment day. The rats were administered morphine, muscimol, baclofen, MK-801, CNQX, N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME) or clonidine i.p., and then electrically stimulated at 0.1 mA to the proximal region to the nerve injury site under urethane anesthesia. Two hours after the stimulation, Fos-LI expression was increased in the spinal cord dorsal horn and the gracile nucleus in control rats. Baclofen inhibited the Fos-LI expression both in the spinal cord and the gracile nucleus. Morphine inhibited only the Fos-LI expression in the posterior cutaneous (PC) nerve territory of laminae I-II, but not in the sciatic nerve (SC) territory, laminae III-IV nor the gracile nucleus. MK-801 had an inhibitory but complicated effect in laminae I-II and the gracile nucleus. The other drugs were not effective on Fos-LI expression. It is suggested that the GABA(B) receptor has a pivotal role in the regulation of Fos-LI expression after electrical stimulation to the injured low-threshold sensory fibers, and other receptors have little effect on the Fos-LI expression.     

The application of Ion chromatographic method for bioavailability and stability test of iron preparations

Postabsorptive serum iron level was determined after oral administration of the compounds to human. In serum and whole blood, Fe3+ was measured by ion chromatography (IC) using a pyridine-2,6-dicarboxylic acid (PDCA) as an eluent. The serum sample solutions were pretreated with I N HCI and 50% TCA. The whole blood sample solutions were treated with 3 N HCI for 30 min at 125 degrees C. The limit of detection (LOD) of the IC technique is 0.2 microM for Fe2- and 0.1 microM for Fe3+. The area under concentration (AUC) can be obtained by the above analytical condition. In addition, to compare the stability of Fe2+ to that of Fe3+ in pharmaceutical preparations, accelerated stability test was carried out. After storing the samples under 40 degrees C, 75%RH in light-resistant container for various time intervals, the contents of iron of different valencies were determined separately by the IC technique and the change and/or the interchange of among those iron species in preparations was investigated. Iron raw materials are stable, but Fe2+ in Fe3+ source materials was slightly converted to Fe3+ by oxidation. Fe2+ in Fe3+ source raw materials and Fe3+ in Fe2+ raw materials are determined as impurities. Therefore, IC technique is found to be an appropriate method for comparative evaluation of dissimilar bioavailability of Fe2+ and Fe3+, stability of Fe2+ and Fe3+ raw materials and preparations.     

载重卡车和拖拉机振动参数的测量及对人体健康影响的研究

本研究对8种载重卡车、拖拉机驾驶员座位的振动进行测量,均超过ISO 2631—1985规定的暴露极限(E·L)界限值。特别是上海50型拖拉机、解放牌4吨翻斗车更为明显。对490名驾驶员进行了一般查体、心电图检查、视觉运动反应时测定和脊柱骨关节X线摄像,并与162名科室办公人员相对照。腰背痛主诉、血压偏高、心电图节律异常、视觉运动反应时减慢、胸腰椎增生性改变等均有较高的检出率,并随工龄的延长而增加。全身振动及其联合因素对人体健康的影响有必要进一步研究;我国全身振动的卫生标准及防治措施急待研制。     

HBV感染者HBV-DNA阳性血清HBeAg阴性的影响因素

目的 探讨HBV感染者HBV—DNA阳性血清HBeAg阴性的影响因素。方法 采用ms—PCR及ELISA方法分别检测HBV感染者血清中A-1896及HBeAg／IC。结果 29例HBV—DNA阳性、HBeAg阴性血清标本，HBeAg／IC阳性17例(58．7％)，单一A-1896者3例(10．3％)，HBeAg／IC及A-1896共存2饲(6．9％)。结论 HBeAg／IC形成是HBV—DNA阳性血清HBeAg阴性的主要原因，而非A-1896。     

甲磺酸帕珠沙星对映异构体的拆分方法及其应用

目的:建立一种用手性流动相拆分并测定甲磺酸帕珠沙星对映异构体的方法。方法:使用HYPERSIL BDS C18柱(4.6mm×250 mm,5μm),流动相为含有3 mmol·L-1硫酸铜、6 mmol·L-1 D-苯丙氨酸的溶液-甲醇(78:22),流速为1 mL·min-1,在250nm检测。结果:R-(+)和S-(-)甲磺酸帕珠沙星的保留时间分别为8.1和9.7 min,分离度为2.2。结论:方法的重现性好,操作简单,可用于药品质量控制。     

高效液相色谱手性流动相法拆分帕珠沙星对映体

目的:对帕珠沙星对映体进行手性分离。方法:采用高效液相色谱手性流动相法,用ODS柱(4.6 mm×150 mm,10 μm),检测波长320 nm,流动相为甲醇-手性溶液(25:75,pH 3.0),流速1 mL·min-1。结果:右旋体最低检测限1.5 ng,重现 性好。结论:该法可用于帕珠沙星光学纯度检查。