Activation of the parapyramidal region in the ventral medulla stimulates gastric acid secretion through vagal pathways in rats

Neurons synthesizing thyrotropin-releasing hormone, substance P and serotonin in the medullary caudal raphe nuclei project to the dorsal vagal complex and play a role in the central vagal regulation of gastric function. Neurons in the parapyramidal region in the ventral medulla share similar biochemical coding and projections as those in the caudal raphe nuclei. The role of the parapyramidal region in the autonomic regulation of gastric acid secretion was investigated in urethane-anesthetized rats. Unilateral microinjection of kainate into the parapyramidal region at 10, 15 and 20 ng induced a dose-related stimulation of gastric acid secretion (net increases: 22.2+/-11.2, 40.5+/-8.5 and 89.8+/-19.4 micromol/60 min, respectively), while injection of vehicle had no effect (net change: -0.1+/-1.4 micromol/60 min). Time-course studies showed a nine-fold peak increase over basal at 30 min after parapyramidal injection of kainate (20 ng) and acid secretion returned to basal level at 70 min. Microinjections of kainate (15-20 ng) outside the parapyramidal region or into the parapyramidal region in vagotomized rats had no effect. Exposure to cold (4 degrees C) for 2 h, which is known to induce vagally mediated gastric secretory and motor responses through medullary thyrotropin-releasing hormone pathways, increased the number of Fos-positive cells in the caudal, middle and rostral parts of the parapyramidal region to 4.3+/-0.4, 9.4+/-0.9 and 18.4+/-1.6/section, respectively, compared with 0.1+/-0. 1, 0.1+/-0.0 and 0.7+/-0.6/section, respectively, in rats maintained at room temperature. Most of the Fos-labeled cells co-expressed pro-thyrotropin-releasing hormone messenger RNA signal and/or were serotonin immunoreactive. These data show that chemical activation of neurons in the parapyramidal region results in a vagal-dependent stimulation of gastric acid secretion and that acute cold exposure activates parapyramidal neurons containing pro-thyrotropin-releasing hormone and/or serotonin, suggesting a potential role of the parapyramidal region, in addition to the caudal raphe nuclei, as medullary sites involved in the vagal regulation of gastric function.     

胸腺因子对小鼠腹腔巨噬细胞影响的电镜观察

小白鼠15只,其中10只作实验组(用胸腺因子激活其腹腔巨噬细胞),5只(以等量生理盐水作对照)。通过扫描与透射电镜观察注射腹腔巨噬细胞的微细结构变化。结果:实验组的巨噬细胞其形态、突起、胞质内溶酶体、空泡、吞噬体、线粒体和游离核蛋白体、吞噬鸡红细胞数等均强于对照组。这些变化与活比巨噬细胞旺盛的功能状态有密切关系,本课题可进一步了解胸腺因子(一种免疫促进剂)。对巨噬细胞的激活与免疫的加强作用,并提供巨噬细胞一些形态学的依据。     

CCKB受体诱发的小鼠神经元蛋白质磷酸化的研究

目的：从蛋白质可逆磷酸化修饰的角度初步勾勒出CCK_B型受体介导的胞内信号转导途径。方法:培养的小鼠大脑皮质神经元分为实验组、对照组和受体拮抗剂组，在无磷培养基加入 ［32P］-NaH₂PO₄标记细胞中的磷蛋白后，刺激组给予CCK₈（10^-7 mol/L），对照组加入等量的无磷培养基，受体拮抗剂组在分别加入CCK_A型、CCK_B型受体拮抗剂L364 718、L365 260以及L364 718＋L365 260，浓度均为10^-8 mol/L，孵育10 min后，再加入10^-7 mol/L CCK₈，37 ℃作用60 min，液氮中终止磷酸化反应。裂解细胞提取蛋白质，双向电泳分离，放射自显影7d后，获得磷酸化蛋白的放射自显影双向电泳图谱。采用PDQuest 2D分析软件对图谱进行差异分析，并在Swiss-Prot蛋白质数据库和自建磷蛋白数据库中查询定性。结果:CCK₈作用60 min后，小鼠神经元CCK₈信号转导相关磷酸化蛋白有：多种蛋白激酶、细胞信号分子、生长因子受体、转录因子等。加入L364 718后，神经元中PKCδ、P55G等的磷酸化水平降低，加入L365 260后， PKCα、PKGβ、OGFR、EGFR等的磷酸化水平呈现不同程度的降低，表明皮质神经元中CCK_B受体介导的信号转导更复杂。结论:CCK_A型、GGK_B型受体均可介导CCK₈在神经元的信号转导，但CCK_B型受体可能发挥了更重要的作用，其介导的信号途径可能包括：肌醇磷脂信使系统、cAMP-PKA途径、MAPK途径、JNK途径、PI3K-PKB途径和cGMP-PKG途径。     

糖皮质激素对膝关节周围成骨细胞一氧化氮合酶和骨重建的影响

目的研究糖皮质激素对膝关节成骨细胞一氧化氮合酶表达和软骨下骨质重建的影响。方法取健康SD大鼠24只，体重（0．45±0．02）kg，随机分为实验组（A组）和对照组（B组），每组12只。实验组每周一次左膝关节腔内注射复方倍他米松0．02ml／kg，对照组每周一次左膝关节腔内注射生理盐水0．02ml／kg。4周时对两组大鼠的左侧膝关节股骨成骨细胞的诱生型一氧化氮合酶（inducible nitric oxide synthase，iNOS）和内皮细胞型一氧化氮合酶（endothelial nitric oxide synthase，eNOS）免疫组织化学研究，测定其平均灰度值和平均积分光密度，同时进行左胫骨软骨下骨质显微结构观察。结果实验组和对照组iNOS免疫组化的结果均为阴性，实验组eNOS的表达显著低于对照组（P〈0．01），实验组左胫骨的软骨下骨质旱骨质疏松特征。结论糖皮质激素对膝关节成骨细胞内皮细胞型一氧化氮合酶的表达和软骨下骨质生成有明显的抑制作用。     

His-tag不影响RSV重组蛋白G1F/M2的免疫原性

目的：观察His-tag是否影响RSV重组蛋白G1F/M2的免疫原性。方法：PCR扩增G1和F/M2基因片段,插入表达载体pET-His和pET-DsbA-His中,转化E.coli BL21（DE3）,IPTG诱导表达,采用Ni^＋螯合亲和层析法纯化得His-G1F/M2和DsbA-His-G1F/M2,将后者用凝血酶消化,再经Ni＋螯合亲和层析法纯化得G1F/M2,将His-G1F/M2和G1F/M2免疫BALB/c小鼠,用ELISA测定抗体滴度,MTT法测定细胞毒性T细胞活性（CTL）。结果：两种蛋白在BALB/c小鼠中诱导的RSV特异性抗体和CTL活性无显著差异。结论：His-tag不影响RSV重组蛋白G1F/M2的免疫原性。     

Determination of gene organization in the human IGHV region on single chromosomes

Organization of the IGHV genes (n=108) on single human chromosomes has been determined by detecting these sequences in single sperm using multiplex PCR amplification followed by microarray detection. A total of 374 single sperm samples from five Caucasian males were studied. Three deletion/insertion polymorphisms (Del I-Del III) with deletion allele frequencies ranging from 0.1 to 0.3 were identified. Del I is a previously reported polymorphism affecting three IGHV genes (IGHV1-8, IGHV3-9, and IGHV2-10). Del II affects a region 2-18 kb containing two pseudogenes IGHV(II)-28.1 and IGHV3-29, and Del III spans approximately 21-53 kb involving genes IGHV4-39, IGHV7-40, IGHV(II)-40-1, and IGHV3-41. Deletion alleles of both Dels II and III were found in a heterozygous state, and therefore, could not be easily detected if haploid samples were not used in the study. Results of the present study indicate that deletions/insertions together with other possible chromosomal rearrangements may play an important role in forming the genetic structure of the IGHV region, and may significantly contribute to antibody diversity. Since these three polymorphisms are located within or next to the 3' half of the IGHV region, they may have an important role in the expressed IGHV gene repertoire during immune response.     

人era的结构特点分析及其定点突变体的构建

目的：构建最近克隆的人era基因的定点突变体。方法：利用数据库对era的结构特点进行分析，在此基础上用改良的重叠延伸法分别构建人EraN端和C端的定点突变体。结果：获得了分别针对人EraN端TGP结合结构域（位于29－36氨基酸残基）和C端具有RNA结合活性的 KH结构域（位于297－340氨基酸残基）的定点突变体。结论:人era定点突变体的构建为进一步的功能研究奠定了基础。     

Emergence of influenza A H1N2 reassortant viruses in the human population during 2001

A recombinant vaccinia virus encoding rotavirus protein NSP3 driven by an internal ribosome entry site (IRES) from the encephalomyocarditis (EMC) virus was able to abate protein synthesis in BSC1 cells by 25-fold, with as much as 30% of the remaining protein synthesis being NSP3. Hence NSP3 shuts off host cell protein synthesis down to the level seen during rotavirus infection but is unable to prevent translation from EMC IRES-driven genes. This effect was abolished by deletions in the eIF4G-binding (aa 274-313) and the dimerization (aa 150-206) but not the viral mRNA-binding (aa 83-149) domains, supporting that NSP3 functions in vivo as a dimer. Binding of eIF4G by NSP3 has been implicated in interfering with mRNA 5'-3' circularization, hence such circularization is essential for translation in mammalian cells.     

High-performance liquid chromatographic analysis of the D4 receptor antagonist SCH 66712 in rat plasma

SCH 66712 is a potent and selective dopamine D4 receptor antagonist. An HPLC method was developed for the analysis of SCH 66712 in the plasma of rats, a species used for safety evaluation of this compound. The method involved solid-phase extraction on an ethyl cartridge and HPLC separation on a reversed-phase C8 column with quantitation using a fluorescence detector. The calibration curve was linear over a concentration range of 5-100 ng/ml. The limit of quantitation was 5 ng/ml, where the coefficient of variation (C.V.) was 2.9% and the bias was 6%. The precision of the method was satisfactory as indicated by an intra-day C.V. of < or = 4% and an inter-day C.V. of < or = 6%. The accuracy was also satisfactory as shown by an intra-day bias of < or = 8% and an inter-day bias of < or = 9%. The assay was shown to be sensitive, specific, accurate, precise, and reliable for use in pharmacokinetic or toxicokinetic studies.     

High-resolution analyses of two different classes of tumor cells in situ tagged with alternative histochemical marker genes.

To evaluate interactions of two different tumor cell classes during the establishment of micrometastases at the single-cell level, two different BALB/c 3T3 tumor cell derivatives were established that harbor different histochemical marker genes: bacterial lacZ in a EJ-Harvey ras transformant (abbreviated LZEJ cells) and human placental alkaline phosphatase (ALP) gene in a human c-sis transformant (APSI cells). Several different histochemical staining methods were evaluated, using the distinctiveness of lacZ and ALP gene activities, for identification of these cell classes singly or together in the lung after their intravenous injection into nude mice. LZEJ and APSI cells could readily be distinguished from each other after co-injection by using specific and sequential staining protocols of whole organs or sections; staining of host organ cells was minimized. Co-injection of the two tumor cell classes resulted in similar numbers of homogeneous microfoci in lungs of LZEJ or APSI cells within minutes after injection that persisted for several hours before clearance of most of them. Furthermore, a significant percentage of foci could be identified containing both classes of tumor cells on whole-organ or section evaluations; these cohabiting foci resisted clearance from lungs. Therefore, use of two different histochemical marker genes to tag different classes of tumor cells provides a powerful approach for determining their in situ co-localization, cooperation, or interference with the establishment and development of micrometastases, as well as an opportunity to evaluate gene regulation in situ at the single-cell level.