Circadian Rhythm of Cardiac Output, Peripheral Vascular Resistance, and Related Variables by a Beat-to-Beat Monitoring

This study aimed to explore the 24-h patterns of stroke volume, cardiac output, and peripheral vascular resistance along with other correlated variables, such as left ventricular ejection time, ejection velocity index, thoracic fluid index, heart rate, and blood pressure. The study was performed on 12 clinically healthy subjects by means of a noninvasive beat-to-beat monitoring using the thoracic electric bioimpedance technique associated with the automated sphygmomano-metric recording. Time data series were analyzed by means of chronobiological procedures. The results documented the occurrence of a circadian rhythm for all the variables investigated, giving relevance to the beat-to-beat bioperiodicity of cardiac output and peripheral vascular resistance. Temporal quantification of the investigated variables may be useful for a better insight of the chronophysiology of the cardiovascular apparatus.     

Vagal nerve and the gastric mucosal defense

An essential role for an intact vagal nerve has been proven in the development of gastric mucosal cyto- and general protection. On the other hand, chemically-induced (ethanol, HCl, indomethacin) gastric mucosal damage is enhanced after acute surgical vagotomy. The aims of this paper were to study the possible mechanisms of the vagal nerve in the development of gastric mucosal defense. The following questions were addressed: 1) effect of surgical vagotomy on the development of ethanol- (ETOH), HCl-, and indomethacin (IND)-induced gastric mucosal damage; 2) changes in the gastric mucosal defense by scavengers, prostacyclin and other compounds (small doses of atropine and cimetidine: 3) changes in the gastric mucosal vascular permeability due to chemicals; 4) effect of indomethacin in the ETOH and HCl models with and without surgical vagotomy; 5) changes in the gastric mucosal content of prostacyclin and PGE₂ in the ETOH and HCl models after surgical vagotomy; and 6) changes in the role of SH-groups in gastric mucosal defense after surgical vagotomy. It was found that: 1) the gastric mucosal damage produced by chemicals (ETOH, HCl, and indomethacin) was enhanced after surgical vagotomy; 2) the cyto- and general gastric protective effects of β-carotene, prostacyclin, and small doses of atropine and cimetidine disappeared after surgical vagotomy; 3) the vascular permeability due to chemicals (ETOH, HCl, indomethacin) significantly increased after surgical vagotomy in association with an increase in both number and severity of gastric mucosal lesions; 4) IND alone (in animals with an intact vagus) did not produce gastric mucosal lesions (in 1-h experiments), but it aggravated ETOH-induced gastric mucosal damage (both its number and severity); 5) the gastric mucosal levels of prostacyclin and PGE₂ decreased after surgical vagotomy; 6) IND application (after surgical vagotomy) decreased further the tissue levels of prostacyclin and PGE₂ in association with an increase of gastric mucosal damage; and 7) the gastric mucosal protective effects of SH-groups were abolished by surgical vagotomy.     

单增李斯特菌胎盘感染的体内外模型研究进展

单核细胞增生李斯特氏菌（Listeria monocytogenes）是重要的食源性致病菌,能引发人类的李斯特菌病,是全球公共卫生问题之一。该菌易感染孕妇,引起胎儿和新生儿的侵袭性李斯特菌病,严重威胁母婴健康。因此,建立有效的单增李斯特菌感染胎盘体内外模型,解析和探究单增李斯特菌经胎盘感染机制,是预防和控制单增李斯特菌感染母婴的关键所在。本文综述了可用于研究单增李斯特菌母婴感染的体内外胎盘模型,总结和讨论了各类模型的优势和局限性;并着重分析了体外三维胎盘屏障模型在单增李斯特菌感染方面的研究进展和未来研究方向。以期为深入解析该菌经胎盘感染的途径、发病机制提供支持,并为预防和控制母婴李斯特菌病提供科学参考。     

谷子不育系及其相应可育系小孢子发育的细胞学观察

以谷子2个品种的不育系及其保持系为材料,对其小孢子发育的细胞形态学进行了观察研究。结果表明:昭盟A花药的外部形态及花粉母细胞的发育过程与昭盟B相似,能形成外观正常的三核花粉,但其花药不能开裂散粉。石炮A表现出了败育时间和方式的多样性,且不育系与保持系间在花药长度上有显著差异。此外,两种不育系的维管束都表现出不同程度的发育不良。不良程度与药囊退化程度相关。     

重庆维管植物1个新记录属和5个新记录种

通过野外调查、资料查阅及馆藏标本比对,确定了重庆维管植物1个新记录属——水东哥属（Saurauia Willd.）及其新记录种——水东哥（Saurauia tristyla DC.）,另4个维管植物新记录种分别是二褶羊耳蒜（Liparis cathcartii Hook. f.）、莸状黄芩（Scutellaria caryopteroides Hand.-Mazz.）、白鳞酢浆草（Oxalis leucolepis Diels）、包氏凤仙花（Impatiens bodinieri Hook. f.）。文中描述了物种识别特征、标本引证和地理分布,提供了原生境照片。引证标本均收藏于西南大学自然博物馆植物标本室（SWNTU）。     

Cytoskeletal arrangement and its intercellular connec-tion in wheat young leaf cells

By using the techniques of partial digestion of cell wall and selective extraction,we examined the cytoskeleton of wheat yong leaf cells under scanning electron microscope(SEM).A 3-dimensional cytoskeletal system,showing some new features,was observed.The cortical network located beneath the cross wall was an anastomosing organization.The association of nucleus with the cell wall by some skeletal filaments was also found.It is notice able that there were cytoskeletal filaments,which passed through cell wall and connected together with cytoskeletal arrays of adjacent cells,Thus,it is possible that an integral skeletal network existed within the yong leaf tissue of wheat.     

Between Xylem and Phloem: The Genetic Control of Cambial Activity in Plants

Abstract: Post-embryonic development is controlled by two types of meristems: apical and lateral. There has been considerable progress recently in understanding the function of root and shoot apical meristems at the molecular level. Knowledge of analogous processes in the lateral, or secondary, meristems, i.e. the vascular cambium or cork cambium, is, however, rudimentary. This is despite the fact that much of the diversity in the plant kingdom is based on the differential functions of these meristems, emphasizing the importance of lateral meristems in the development of different plant forms. The vascular cambium is particularly important for woody plants, but it also plays an important role during the development of various herbaceous species, such as Arabidopsis thaliana. In this review, we focus on the two basic functions of cambial activity: cell proliferation and pattern formation.     

大鼠基底动脉和尾动脉平滑肌G蛋白的异质性

用离体血管收缩功能实验法分析了大鼠基底动脉（ＢＡ）和尾动脉（ＣＡ）平滑肌细胞Ｇ蛋白的异质性。结果显示,当ＢＡ和ＣＡ平滑肌被精氨酸血管加压素（ＡＶＰ）激动后,该两种血管对Ｇ蛋白非选择性激活剂ＧＴＰγＳ的收缩反应发生了相反的变化：ＢＡ对ＧＴＰγＳ的收缩增强,并且这种收缩增强不受百日咳毒素（ＰＴ,Ｇｉ和Ｇｏ抑制剂）的影响。而霍乱毒素（ＣＴ,Ｇｓ激活剂）则完全抑制这种收缩,呈单相反应。与ＢＡ相反,ＣＡ对ＧＴＰγＳ的收缩减弱,后者可被ＰＴ预温育反转为收缩增强,而且ＣＴ对这种收缩的抑制作用短暂,呈双相反应。结果提示,ＢＡ和ＣＡ平滑肌细胞介导激动剂收缩反应的Ｇ蚕白存在异质性。     

Observations on rodlet cells found in the vascular system and extravascular space of angelfish (Pterophyllum scalare scalare)

In the angelfish ( Pterophyllum scalare scalare ) numerous rodlet cells were found in the large post-orbital blood vessel caudal to the eye and in the surrounding extravascular space. Within the vessel the rodlet cells formed striking regular arrays, along the inner aspect of the wall. The rodlets within the cells were positive to PAS but negative to Sudan Black B, Masson's, and the Fuelgen stain. The capsule around the cells was negative for all these stains. These rodlet cells appeared to be traversing the vessel endothelium, and to be pushing the endothelium aside without damaging it. Some discharged their contents into the vessel, but we never observed the release of intact rodlets. The nuclei of rodlet cells in actual contact with the vessel were at the end of the cell more distant from the endothelial wall. Cell-to-cell adhesion structures or communications junctions between rodlet cells and the endothelium were not evident. A putative rodlet cell precursor in the extravascular space contained large electron-dense granules, and extended pseudopodia that contacted nearby rodlet cells. Based on their morphology, tissue distribution, and their behaviour, we conclude that the rodlet cell is an endogeneous teleost cell type, and possibly represents a form of matured granulocyte.     

Divergence of the phytochrome gene family predates angiosperm evolution and suggests thatSelaginella andEquisetum arose prior toPsilotum

Thirty-two partial phytochrome sequences from algae, mosses, ferns, gymnosperms, and angiosperms (11 of them newly released ones from our laboratory) were analyzed by distance and characterstate approaches (PHYLIP, TREECON, PAUP). In addition, 12 full-length sequences were analyzed. Despite low bootstrap values at individual internal nodes, the inferred trees (neighbor joining, Fitch, maximum parsimony) generally showed similar branching orders consistent with other molecular data. Lower plants formed two distinct groups. One basal group consisted of Selaginella, Equisetum, and mosses; the other consisted of a monophyletic cluster of frond-bearing pteridophytes. Psilotum was a member of the latter group and hence perhaps was not, as sometimes suggested, a close relative of the first vascular plants. The results further suggest that phytochrome gene duplication giving rise to a- and b- and later to c-types may have taken place within seedfern genomes. Distance matrices dated the separation of mono- and dicotyledons back to about 260 million years before the present (Myr b.p.) and the separation of Metasequoia and Picea to a fossil record-compatible value of 230 Myr B.P. The Ephedra sequence clustered with the c- or a-type and Metasequoia and Picea sequences clustered with the b-type lineage. The paleoherb Nymphaea branched off from the c-type lineage prior to the divergence of mono- and dicotyledons on the a- and b-type branches. Sequences of Piper (another paleoherb) created problems in that they branched off from different phytochrome lineages at nodes contradicting distance from the inferred trees' origin. Correspondence to: H.A.W. Schneider-Poetsch