关于经络是一种细胞外基质通道的假说

经络的客观存在得到实验证实，但是关于经络形成机制的研究尚未见报道。在整合国内外相关实验成果的基础上，研究发现经络系统的主体——十二经脉与细胞迁移通道具有相似的形成机制。呼吸中吸气肌节律性收缩或四肢、躯干运动等使相应的经穴打开，进而使穴区肥大细胞（MC）胞膜上辣素受体-2（TPRV₂）通道开通，介导Ca²⁺和Na⁺内流，MC被激活。MC脱颗粒释放两种丝氨酸蛋白酶，分泌介质刺激成纤维细胞等使之合成、分泌两种基质金属蛋白酶原，该两种酶原被丝氨酸蛋白酶活化成酶。丝氨酸蛋白酶和基质金属蛋白酶共同作用，降解细胞外基质蛋白质，开辟出十二经脉通道。由此推测：经络是酶促反应形成的空间定位、时间稳定的细胞外基质通道。     

SC1, A SPARC-related glycoprotein, exhibits features of an ECM component in the developing and adult brain

Although extracellular matrix (ECM[ components have been shown to play important roles in the development of the CNS, expression generally decreases in the adult brain. This study examines the expression of the SPARC-related glycoprotein SC1 in the rat brain during postnatal development and in the adult. In situ hybridization analysis indicates that expression of SC1 mRNA increases in a caudal to rostral manner as postnatal neural development proceeds and is found at near maximal levels in the adult brain. SC1 mRNA is expressed in glial-enriched areas of the brain at postnatal day 1 (P1[ and P5. Between P10 and P20, SC1 mRNA increases in neuron-enriched regions of the hippocampus, dentate gyrus, and cerebral cortex. Immunohistochemistry in the adult shows that SC1 protein is localized to neurons in these regions and to scattered glial cells. Subcellular fractionation demonstrates that the SC1 116/120 kDa doublet is associated with synaptosomes. SC1 is present in the aqueous phase following extraction of membranes with TX-114, suggesting that it is not a transmembrane protein, a property consistent with other adult brain ECM components. Furthermore in cerebellar granule cells grown in culture, high levels of the 120 kDa component are secreted into the media. These results are consistent with the hypothesis that SC1 is an ECM glycoprotein expressed in both the developing and adult brain.     

秋水仙碱对大鼠肺纤维化的干预作用

目的研究秋水仙碱（Ｃｏｌｃ．）对博菜霉素（ＢＬＭ）所致大鼠肺纤维化的干预作用，探讨治疗肺间质纤维化的新途径。方法Ｗｉｓｔａｒ大鼠随机分为３组，每组２５只，１组为ＢＬＭ组，气管内注入０．５％ＢＬＭＡ５０．１ｍｌ／１００ｇ体重，复制肺纤维化动物模型，２组为生理盐水对照组，３组为药物干预组，大鼠于ＢＬＭ灌注后每日胃内灌入Ｃｏｌｃ．１０μｇ／１００ｇ体重。三组动物于气管内灌注后第１、３、７、１４、２８天分别随机处死５只，进行支气管肺泡灌洗并收集灌洗液。采用生物活性检测法，测定肺泡巨噬细胞释放细胞因子的变化，细胞外基质蛋白及脂质过氧化损伤的检测，分别采用放免法及生化法。结果秋水仙碱组于灌胃后第７～２８天，白细胞介素６（ＩＬ－６）水平较ＢＬＭ组降低（Ｐ＜０．０５），但仍高于对照组；ＩＬ－８于第１～３天显著下降（Ｐ＜０．０１）；肺内羟脯氨酸（ＨＹＰ）及纤维连结蛋白（ＦＮ）、层粘连蛋白（ＬＮ）含量明显降低。Ｃｏｌｃ．对脂质过氧化损伤未显示出防护作用。结论秋水仙碱对大鼠实验性肺纤维化有一定防护作用     

Preparation of clear solutions of reconstituted acetylcholinesterase Effect of ionic strength and lipid/protein ratio

The detergent-soluble globular dimer of acetylcholinesterase from Torpedo californica was reconstituted through dialysis into preformed egg phosphatidylcholine vesicles. The formation of the enzyme-lipid complexes depended on the ionic strength of the dialysis buffer as well as the molar lipid/protein ratio (R). The enzyme was unstable at I < 0.05; increasing the ionic strength increased the size of the complex. A too low R value (e.g. 1000) would promote self-aggregation of the enzyme and produce heterogeneous complexes, especially at high I values. On the other hand, a too high R value (e.g. > 5000) favored the formation of large enzyme-lipid complexes; their solutions were too turbid for optical studies. The enzyme reconstituted at I = 0.07 and R = 4000 gave a clear solution and showed no artifacts due to light scattering. The conformation based on circular dichroism and enzymatic activity of the detergent-soluble enzyme were unchanged upon reconstitution. The reconstituted enzyme in lipid vesicles seemed to be slightly more stable against thermal denaturation than the protein in sodium cholate solution.     

Distribution of thalamic nociceptive neurons activated from the tail of the rat

The purpose of the present study was to map systematically in the thalamus the distribution of neurons processing nociceptive information from the tail of the rat. Pentobarbital-anesthetized and gallamine-paralyzed rats were used. Glass microelectrodes were used to record extracellularly from thalamic neurons. Noxious radiant heat stimuli were applied to the tail with a tail-flick apparatus, and the recorded neurons were localized with horseradish peroxidase deposits or by marking electrodes left in situ. A number of 121 neurons were tested of which 45 responded. Of these, 13 were located in the ventrobasal complex (VB), 17 were located in the central lateral nucleus and the parafascicular nucleus of the intralaminar nuclei (ILN). The rest of the responding neurons were located in the posterior group, the reticular thalamic nucleus, and the zona incerta. The nucleus submedius was not examined specifically. It is concluded that the VB and the ILN are two of the most important thalamic nuclei for processing nociceptive information from the tail of the rat.     

Acute and long-lasting changes in extracellular-matrix chondroitin-sulphate proteoglycans induced by injection of chondroitinase ABC in the adult rat brain

Lattice-like perineuronal accumulations of extracellular-matrix proteoglycans have been shown to develop during postnatal maturation and to persist throughout life as perineuronal nets (PNs) in many brain regions. However, the dynamics of their reorganization in adults are as yet unknown. The aim of the present study was to examine the capability of PNs for reconstitution after experimental destruction and to search for possible consequences of extracellular-matrix degradation for neurons and glial cells. The changes were induced by single intracortical injections of Proteus vulgaris chondroitinase ABC and studied after postinjection periods of 1 day to 5 months. The N-acetylgalactosamine-binding Wisteria floribunda agglutinin (WFA), an antibody against chondroitin-sulphate proteoglycans, three antibodies recognizing initial chondroitin or chondroitin-sulphate moieties (’stubs’) of proteoglycan core proteins, an antibody against the hyaluronan-binding protein component of versican, and biotinylated hyaluronectin, which binds to hyaluronan, were used as cytochemical markers. One day postinjection, the WFA-binding sites and hyaluronan were shown to be almost completely removed within a circumscribed digestion zone. The staining of different core-protein components revealed only fragments of PNs. These changes were found to be partly compensated 4 weeks after injection of chondroitinase ABC. After 8 and 12 weeks postinjection, the cytochemical and structural characteristics as well as the area-specific distribution patterns of PNs were progressively reconstituted. At 5 months postinjection, they could not be distinguished from those in untreated tissue. In contrast to such transient changes, a diffuse chondroitin-sulphate proteoglycan immunoreactivity persisted in the neuropil. Loss of neurons or alterations of their structure as well as reactions of glial cells were not observed. We conclude from this study that PNs, enzymatically destroyed in the adult rat brain, can be completely reconstituted, but the restoration of their extracellular-matrix components needs several months. Received: 16 December 1997 / Accepted: 17 February 1998     

Comparison of the abilities of synthetic and platelet-derived membranes to enhance thrombin formation

The relative abilities of platelet-derived membranes and synthetic phospholipid vesicles to enhance the prothrombinase-catalyzed conversion of prothrombin to thrombin have been determined. For each type of membrane, the maximum amount of thrombin formed as a function of amount of available lipid was measured using a chromogenic substrate assay. The lipid concentration at which the amount of thrombin formed began to exceed that formed in the absence of lipid (critical phospholipid concentration) was used to compare the surfaces′ abilities to support thrombin formation. For platelet derived membranes and for equimolar, charged-lipid/phosphatidylcholine (PC) vesicles, the critical concentrations increased in the following order: platelet-derived membranes phosphatidylserine (PS) phosphatidic acid (PA) « monomethyl PA and monoethyl PA « phosphatidylinositol and phosphatidylglycerol. For mixed anionic/ neutral lipid vesicles above their phase transitions, measured critical concentrations were relatively insensitive to changes in lipid acyl chains, the neutral lipid component, and membrane curvature but were sensitive to changes in the anionic lipid content of the mixtures. Comparison of these data suggested that equimolar PS/PC and PA/PC vesicles can emulate reasonably well the thrombin-generating ability of platelet-derived membranes.