Ciliated Cells in the Human Gastric Mucosa Evidence of Metaplastic Change

In the gastric mucosa of Japanese patients, ciliated cells were found in association with intestinal metaplasia. The cells occurred frequently in the pyloric mucosa of nearly half of the cases examined but rarely in the cardiac mucosa of total 12 cases, but never adjacent to the chief cells of gastric glands. The ciliated cells were always found in the basal part of cardiac and pyloric glands, but never in the surface or in the foveolar epithelium. Furthermore, ciliated cells containing a few small mucus granules and simultaneously possessing numerous cilia and basal bodies were noted. Ciliated cells in the gastric mucosa have been found mainly in elderly Japanese patients, but were also observed exceptionally in one Chinese, two Swedes and one American. These ciliated cells are not present in the normal human gastric and intestinal mucosa, and therefore a new term, "ciliated metaplasia", is proposed for their occurrence. Acta Pathol Jpn 40: 98–106, 1990.     

Barium blocks cell membrane and tight junction conductances inNecturus gallbladder epithelium

The site and concentration dependence of the blocking effect of Ba²⁺ onNecturus gallbladder epithelium has been investigated. A new approach was used which combines time-dependent electrical cell coupling analysis with intermittently performed measurements of transepithelial and apparent intracellular impedance. From the coupling pulse data the sum of apical and basolateral membrane conductances is obtained, which is then held constant during fitting of the impedance data. This combination technique yields more reliable estimates of apical and basolateral membranes resistances (R _a,R _bl) and of tight junction resistance (R _j) than our previous impedance analysis technique. Using the new approach we have found that luminal Ba²⁺ concentrations between 0.5 and 1.0 mmol/l increaseR _a with saturation-type kinetics without affectingR _bl andR _j, while higher luminal Ba²⁺ concentrations progressively increaseR _j. Corresponding effects were observed under serosal Ba²⁺. The results validate the new impedance analysis approach and demonstrate that millimolar concentrations of Ba²⁺ block tight junction conductances. Accordingly, Ba²⁺ can no longer be considered a tool to exclusively alter cell membrane resistances in epithelia.     

Identification of a voltage- and calcium-dependent non-selective cation channel in cultured adult and fetal human nasal epithelial cells

The apical membranes of cultured human nasal epithelial cells from adults and fetuses were investigated with the patch-clamp technique. Amiloride-insensitive, calcium- and voltage-dependent, non-selective cation channels were found in 4% of the cell-attached, and 18% of the inside-out and outside-out patches (n=412). Multiple functional channels were present in more than 90% of these patches, with a mean of 3.9 channels per patch (n=55). The current-voltage relationship can be described by the Goldman equations and the single channel conductance was 20.1±0.3 pS (n=29) in adult and 20.7±0.4 pS (n=44) in fetal cells in symmetrical 150mM NaCl solutions. The channels were highly selective for cations: P_Na/P_Cl was 30 in adult and 45 in fetal experiments. They were equally permeable for K⁺ and Na⁺, somewhat less for Cs⁺, and impermeable for choline⁺ and tetraethylammonium⁺. The open probability was voltage dependent: it increased approximately 2-fold with 30mV depolarization in the potential range from −60mV to +60mV. The channels were activated by Ca²⁺ concentrations of about 10⁻⁴M at the cytoplasmic side, but were insensitive to extracellular Ca²⁺ and amiloride (10⁻⁴M). The non-selective cation channels found in apical membranes of cultured fetal nasal epithelial cells were not different from the adult ones.     

聚甲基丙烯酸羟乙酯水凝胶人工晶状体材料的合成与性能

以甲基丙烯酸羟乙酯为原料,过硫酸铵/偏重亚硫酸钠为引发体系,二甲基丙烯酸三乙二醇酯为交联剂,采用溶液聚合法制备了聚甲基丙烯酸羟乙酯水凝胶(PHEMA)人工晶状体材料。系统考察了聚合反应时间、温度及引发剂和交联剂的用量等对该水凝胶材料机械强度、平衡水含量(EWC)的影响,并对PHEMA水凝胶的结构和光学性能进行了表征。实验结果表明,PHEMA水凝胶的最佳合成条件为:引发剂0.5wt%,交联剂1.0wt%,反应温度40℃,反应时间36h。在此条件下制备的PHEMA水凝胶的拉伸强度达到0.57MPa,邵氏A硬度为23.0,平衡含水量超过40%,透光率≥97%。     

Experimental rat model for therapeutic retinal pigment epithelium transplantation—unequivocal microscopic identification of human donor cells by in situ hybridisation of human-specific Alu sequences

Transplantation of retinal pigment epithelial (RPE) cells is discussed as a possible therapeutic approach for retinal degeneration. Xenogeneic transplantation of human RPE cells in animal models has been studied extensively. Various methods have been used to identify the graft cells, but these methods interfere with cell behaviour so that the monitored physiological post-transplantation course may be influenced. In the present study, we applied a method for an unequivocal identification of the graft cells without interfering cell metabolism or behaviour using in situ hybridisation (ISH) of human specific Alu sequences. Visualisation of the strong extended nuclear signal of Alu sequences was much easier than that of the small nuclear signals of donor-specific sex chromosome probes. With Alu probe, even single graft cells can be identified and their development can be observed in short-term and long-term studies. With this procedure, we could prove that donor cells were injected correctly into the subretinal space by a special injection technique that we developed previously. In combination with immunohistochemistry, donor cells could be clearly discriminated from macrophages, which contained phagocytosed donor cell fragments. Application of these ISH methods for species-specific identification was valuable for follow-up-studies of RPE transplantation.     

Effects of vitamin A on proliferation of human distal airway epithelial cells in culture

Using a serum-free culture method, we investigated the effects of vitamin A on the proliferation of human distal airway epithelial cells. Outgrowth of epithelial cells from lung tissue explants was enhanced by treatment with all-trans retinol at concentrations of 10^–8 to 10^–7 M. The colony-forming activity of cells harvested from the primary culture and replated onto Swiss 3T3 fibroblastic feeders was, in contrast, significantly reduced by 10^–7 M to 10^–5 M retinol. When the primary cells were harvested and subcultured on Primaria plates, population expansion was also inhibited by retinol at 10^–10 to 10^–6 M. We further investigated the cells to determine whether there was any difference in sensitivity to the growth-inhibitory effects of vitamin A between cells from the primary culture incubated with and without retinol. The population increase in cells harvested from the primary culture was inhibited equally in retinol-treated and non-treated cells by subsequent treatment with retinol or retinoic acid, this inhibition being dose-dependent. DNA synthetic activity was also inhibited. Interestingly, both the growth rate and the colony-forming efficiency on feeders were greater in the subculture of cells from the retinol-treated primary culture than in those non-treated. When the cells in the secondary subculture were treated with retinoic acid and replated again, they showed a greater population increase rate than those non-treated. Our results showed that human distal airway epithelial cells isolated from lung tissue were sensitive to the growth-inhibitory effect of vitamin A, but the proliferative potential in some fraction of the epithelial cell population was possibly enhanced by vitamin A treatment.     

Modulation of Cytokeratin Expression in The Hamster Thymus: Evidence For a Plasticity of The Thymic Epithelium

Cytokeratin (CK) expression was investigated, by means of immunocytochemistry, in the hamster thymic epithelium during ontogeny, as well as in primary cultures and upon glucocorticoid hormone treatment in vivo. As compared to the distribution pattern of distinct monoclonal antibody-defined cytokeratins in the normal adult thymus, CK modulation was evidenced in the three situations studied. During thymus ontogeny, both cytokeratins of simple lining epithelia, as CK8 and CK18, as well as the CK1/CK10 pair (typical marker of terminal stage of keratinization), were expressed since early stages of thymus development. They were located in the central region of thymic lobules preceding the cortical-medullary distinctions. This differed from what had been previously shown for mouse thymus ontogeny, revealing that the interspecific diversity in the distribution pattern of thymic cytokeratins occurred early in fetal life. A modulation of CK expression was also detected when hamster thymic epithelial cells (TEC) were led to grow in culture, with a down-regulation of CK19 contrasting with an enhancement of CK18 expression. This diverged from the maintenance of the in situ pattern when human TEC were cultured. Last, in vivo hydrocortisone treatment, known to increase the numbers of KL1⁺ cells in the mouse thymus medulla, promoted a cortical expression of the CK1/CK10 pair in the hamster thymus. Taken together, our findings demonstrate a continuous plasticity of the thymic epithelium, at least regarding cytokeratin expression, and enlarge the concept of interspecific diversity of intrathymic CK distribution in conditions as morphogenesis, in vitro system, and responsiveness to glucocorticoid hormone treatment.     

Human lung cancer cell lines express cell membrane complement inhibitory proteins and are extremely resistant to complement-mediated lysis; a comparison with normal human respiratory epithelium in vitro,and an insight into mechanism(s) of resistance

Human lung cancer expresses cell membrane complement inhibitory proteins (CIP). We investigated whether human lung cancer cell lines also express cell-membrane CIP molecules and whether the biology of CIP molecules in these cell lines differs from that of CIP in normal human respiratory epithelium in culture. The cell lines ChaGo K-1 and NCI-H596 were compared with normal human nasal epithelium in primary cultures in respect to the level of cell membrane CIP expression of membrane cofactor protein (MCP; CD46), decay-accelerating factor (DAF; CD55) and CD59, in respect to the level of cell resistance to complement-mediated lysis, and in respect to the contribution of cell membrane CIP to cell resistance against complement-mediated lysis. We found, using flow cytometry, that both human lung cancer cell lines expressed MCP, DAF and CD59, as did normal nasal epithelial cells. However, normal cells showed a large subpopulation of low DAF-expressing cells (60% of all cells) and a smaller subpopulation of high DAF-expressing cells (40%), while the lung cancer cell lines showed only one cell population, of high DAF expression. In addition, both lung cancer cell lines expressed higher MCP levels, and NCI-H596 cells showed higher levels of CD59. Cell resistance to complement-mediated lysis of both lung cancer cell lines was much higher than that of normal cells. Fifty percent normal human serum, under the same concentrations of complement activators, induced lysis of less than a mean of 10% of lung cancer cells, while lysing up to a mean of 50% of nasal epithelial cells. Lung cancer cell resistance to complement was due to its ability to prevent significant activation of complement upon its cell membrane, as manifested by a failure of complement activators to increase cell membrane deposition of C3-related fragments. The exact mechanism for this resistance remains obscure. Unexpectedly, neutralizing antibodies, anti-MCP and anti-DAF were entirely ineffective and anti-CD59 was only slightly effective (18% mean cell lysis) in increasing the susceptibility of the lung cancer cell lines to complement, while the same antibodies were very effective in facilitating complement-mediated lysis of the normal nasal epithelial cells (50% mean cell lysis with CD59 MoAb). On the other hand, detachment of DAF and CD59 by phosphatidylinositol-specific phospholipase C (PIPLC) from the lung cancer cell lines abrogated their resistance to lysis. We suggest that the biology of cell membrane CIP molecules in human lung cancer cell lines is different from that of CIP in normal respiratory epithelial cells. Human lung cancer cell lines are able to prevent significant complement activation upon its cell membrane and are therefore especially resistant to complement-mediated lysis. Complement resistance may serve this common and highly lethal human cancer as an escape mechanism from the body's immunosurveillance and prevent effective immunotherapy with tumour-specific MoAbs.     

白内障晶状体上皮细胞及晶状体纤维超微结构的观察

应用胎儿晶状体发育的超微结构为形态学依据,观察老年性、外伤性、先天性白内障晶状体的超微结构.结果:老年性白内障晶状体上皮多数细胞膜破裂,作者首先发现其原因是相邻细胞顶部的紧密连结缺失,房水侵入所致.胞质中线粒体空泡化,内质网扩张、脱粒.晶状体纤维膨胀、崩溃.细胞之间的各种连结消失.外伤性白内障除具有白内障特点外,胞质中出现大量溶酶体、残体.1例先天性白内障,上皮细胞发育尚好,晶体纤维不发育.