Expression of Na+/HCO3− co‐transporter proteins (NBCs) in rat and human skeletal muscle

Aim: Sodium/bicarbonate co‐transport (NBC) has been suggested to have a role in muscle pH regulation. We investigated the presence of NBC proteins in rat and human muscle samples and the fibre type distribution of the identified NBCs. Methods and results: Western blotting of muscle homogenates and sarcolemmal membranes (sarcolemmal giant vesicles) were used to screen for the presence of NBCs. Immunohistochemistry was used for the subcellular localization. The functional test revealed that approximately half of the pH recovery in sarcolemmal vesicles produced from rat muscle is mediated by bicarbonate‐dependent transport. This indicates that the NBCs are preserved in the vesicles. The western blotting experiments demonstrated the existence of at least two NBC proteins in skeletal muscle. One NBC protein (approximately 150 kDa) seems to be related to the kidney/pancreas/heart isoform NBC1, whereas the other protein (approximately 200 kDa) is related to the NBC4 isoform. The two NBC proteins represent the electrogenic isoforms named NBCe1 and NBCe2. Membrane fractionation and immunofluorescence techniques confirmed that the two NBCs are located in the sarcolemmal membrane as well as in some internal membranes, probably the T‐tubules. The two NBCs localized in muscle have distinct fibre type distributions. Conclusions: Skeletal muscle possesses two variants of the sodium/bicarbonate co‐transporter (NBC) isoforms, which have been called NBCe1 and NBCe2.     

PCBP1:一种在多水平上参与基因表达调控的蛋白因子

多聚胞嘧啶结合蛋白1 (poly C binding protein-1,PCBP1),属于RNA结合蛋白亚家族,因其具有同RNA的多聚胞嘧啶(poly C)区域特异的结合活性而得名.目前该亚家族共有5个成员:hnRNP K(heterogeneous nuclear ribonucleoprotein K)、PCBP1、PCBP2、PCBP3和PCBP4.PCBP1蛋白在多个水平参与基因的表达调控,如转录、mRNA加工、mRNA的转运、mRNA稳定以及翻译水平调控等.本文对PCBP1基因的结构和生物学功能进行了综述.     

临床路径在大肠癌手术患者中的应用

目的:研究临床路径在大肠癌手术患者中的应用效果。方法:选择广东省江门地区某三甲医院2006年7月至2007年12月间实施临床路径的大肠癌手术患者192例作为实验组,对照组选择该院2005年1月至2006年6月间未实施临床路径按常规模式实施的大肠癌手术患者174例,比较两组患者在住院日、住院费用、患者满意度等方面有无差异性。结果:实验组患者的平均住院日、住院费用等方面明显低于对照组(P<0.01),患者满意度优于对照组(P<0.01)。结论:按临床路径对大肠癌手术患者实施围手术期诊疗护理计划,可减少患者平均住院日,降低住院费用,提高医疗护理服务质量及患者满意度,为进一步扩大临床路径的临床应用范围提供实验数据。     

Mapping the rat somatosensory pathway from the anterior cruciate ligament nerve endings to the cerebrum

The anterior cruciate ligament (ACL) serves as the primary restraint to anterior tibial translation. In addition to this biomechanical function, the ACL appears to have a function in neuromuscular control. This hypothesis was formulated after the discovery of mechanoreceptors within the ACL. The full somatosensory pathway from the ACL to the cerebrum has yet to be elucidated. In order to map this sensory pathway, we conducted a viral trans-synaptic tracing experiment using the neurotropic pseudorabies virus (PRV). The pseudorabies virus was injected into the ACL of rats and allowed to replicate and spread trans-synaptically for 6-7 days. The brain and spinal cord of each sacrificed rat was then removed and processed immunohistochemically to detect the presence of PRV. PRV-immunoreactive neurons were found to be localized in several different regions from the spinal cord to the cerebrum. Four nuclei in the reticular formation of the brain stem demonstrated strong positive labeling: the mesencephalic reticular nucleus, magnocellular reticular nucleus, paragigantocellular reticular nucleus, and gigantocellular reticular nucleus. This finding suggests that the nerve endings of the rat ACL project into the cerebrum and that the reticular formation may play an important role in the afferent pathway of those nerve endings.     

细胞凋亡相关新基因TFAR19(PDCD5)研究进展

细胞凋亡是在一定的生理或病理条件下。由基因控制的细胞自我毁灭过程。凋亡异常与许多疾病(尤其是肿瘤)的形成及发展进程密切相关。细胞凋亡调控机制研究证明。多种基因(如P53、C-myc、Bcl-2、Bax等)参与了细胞凋亡的调控过程。TFAR19基因是由我国科研人员最近新发现的另一重要的凋亡相关基因，笔者主要就其结构特点、性质功能、临床意义作一概述。     

兔骨髓基质细胞诱导分化为胰岛素分泌细胞的方法

目的 探讨将骨髓基质细胞（MSCs）诱导成为胰岛素分泌细胞（IPCs）的方法。方法 体外培养新西兰兔骨髓及胰腺基质细胞和SD大鼠胰腺基质细胞，利用含有胰腺基质细胞培养基的混合培养基诱导培养MSCs。结果 以兔及SD大鼠胰腺基质细胞培养基均可诱导兔MSCs生成IPCs。结论 兔及SD大鼠的胰腺基质细胞培养基均可将兔MSCs诱导分化为IPCs。     

Malignant chiasmal glioma: a rare cause of rapid visual loss

The clinical, neuroradiological, and histological findings of an adult patient suffering from malignant optic glioma is reported. Rapid visual deterioration was misdiagnosed for several months until biopsy confirmed the tumor. The patient died despite radiation therapy nine months after first symptoms. Our presentation will focus on the problems of diagnosing and establishing therapeutic procedures in this rare malignant neoplasm.     

Secretogranin I (chromogranin B) mRNA accumulation is hormonally regulated in GH3B6 rat pituitary tumor cells

Secretogranin I (SgI; chromogranin B) belongs to a class of acidic tyrosine-sulfated secretory proteins believed to play a role in the secretory process of endocrine cells. Our aim here was to compare the levels of SgI mRNA to that of prolactin (PRL) and growth hormone (GH), using rat pituitary cell lines. As far as the constitutive expression is concerned, we found a positive correlation between SgI mRNA and PRL mRNA levels. However, the neuropeptide TRH (50 nM) inhibited the accumulation of SgI mRNA in GH3B6 cells whereas, as expected, it induced a rapid and sustained increase in PRL mRNA accumulation. By contrast, 17β-estradiol (1 nM) stimulated the accumulation of both SgI and PRL mRNAs, with the same EC₅₀ (18–59 pM). Reciprocally, treatment with dexamethasone (100 nM) reduced the level of SgI and PRL mRNAs to 23% and 29% of control, respectively, but led to a 2.1-fold increase in the GH mRNA level. Altogether, the present work shows that SgI gene expression is subject to multiple hormonal regulations and occasionally parallels the regulation of the PRL gene but never that of the GH gene, under the conditions tested.     

Axonal transport of dopamine D1 receptors in the rat brain

Binding of a specific dopamine D₁ receptor antagonist,¹²⁵I-SCH 23982, was measured in rat brain sections by quantitative autoradiography at various time intervals, following a knife cut through the striatonigral pathway. Twenty-four hours after lesioning, accumulations of D₁ receptor binding sites were found in sagittal sections both rostral and caudal to the lesion site. No other regions studied (caudate-putamen, nucleus accumbens, olfactory tubercle, and substantia nigra pars reticulata) showed any change in D₁ receptor binding 24h after the lesion. In brain sections obtained 10 days after lesioning, only the substantia nigra pars reticulata had a significant decrease in D₁ receptors ipsilateral to the lesion. These findings suggest the possibility of a presence of bidirectional axonal transport of D₁ receptors in rat striatonigral pathway.     

The effects of anesthesia on otoacoustic emissions

We have measured transient-evoked and distortion-product otoacoustic emissions (OAEs) in the chinchilla and compared them in the awake and anesthetized animal (using either ketamine or barbiturate agents). We report a significant increase in OAE amplitudes during anesthesia, particularly using ketamine. These effects are most evident for transient-evoked otoacoustic emissions (TEOAEs) as measured in the non-linear mode. Our data support the hypothesis that tonic activity levels in cochlear efferents may be reduced by anesthetic effects, either directly or indirectly (e.g., by general reductions in descending pathway activity), and that reduced cochlear efferent activity will result in the observed increase of OAE amplitudes.