Melanin pigmentation: an in vivo model for studies of melanosome kinetics within keratinocytes

The phagocytosis of latex beads by epidermal cells is proposed as a model for stludies on melanosome kinetics within the epidermis. Large latex beads (0.8 micrometer) are ingested singly, whereas, small beads (0.1 micrometer) are taken up in groups, results showing that the uptake mechanism depends on the size of thze indlividual particles. This size-dependency may explain the different distribution patterns of melanosomes and thus the differences of skin color in the Caucasoid and Negroid races.     

Corticotropin-releasing activity of monokines

Hepatocyte-stimulating factor and interleukin-1 are proteins produced by monocytes in response to inflammatory challenge. Neither of these monokines had direct effects on steroid production by cultured adrenocortical cells. Both monokines stimulated pituitary cells (AtT-20) to release adrenocorticotropic hormone; interleukin-1 was equipotent with a combination of corticotropin-releasing factor and arginine vasopressin, and hepatocyte-stimulating factor was at least three times as effective. The synthetic glucocorticoid, dexamethasone, inhibited production of hepatocyte-stimulating factor by cultured monocytes. These results indicate an axis between monocytes and pituitary and adrenocortical cells which may play a role in regulating host defense.     

Identification of monocyte chemotactic activity produced by malignant cells

Human malignant cells secrete low molecular size proteins that attract peripheral blood monocytes and may be responsible for the accumulation of tumor-associated macrophages observed in vivo. Similar chemotactic proteins are secreted by cultured vascular smooth muscle cells. The predominant monocyte chemoattractants produced by tumor cells of differing origin were demonstrated to be related to smooth muscle cell-derived chemotactic factor. Thus, a single class of chemotactic proteins is produced by different cell types, which suggests a common mechanism for the recruitment of monocytes and macrophages. These results are significant in view of the potential of macrophages to affect tumor growth.     

Induction of macrophage tumoricidal activity by granulocyte-macrophage colony-stimulating factor

Monocytes are a subpopulation of peripheral blood leukocytes, which when appropriately activated by the regulatory hormones of the immune system, are capable of becoming macrophages--potent effector cells for immune response to tumors and parasites. A complementary DNA for the T lymphocyte-derived lymphokine, granulocyte-macrophage colony-stimulating factor (GM-CSF), has been cloned, and recombinant GM-CSF protein has been expressed in yeast and purified to homogeneity. This purified human recombinant GM-CSF stimulated peripheral blood monocytes in vitro to become cytotoxic for the malignant melanoma cell line A375. Another T cell-derived lymphokine, gamma-interferon (IFN-gamma), also stimulated peripheral blood monocytes to become tumoricidal against this malignant cell line. When IFN-gamma activates monocytes to become tumoricidal, additional stimulation by exogenously added lipopolysaccharide is required. No such exogenous signals were required for the activation of monocytes by GM-CSF.     

Monocyte-derived human B-cell growth factor identified as interferon-beta 2 (BSF-2, IL-6)

Soluble products of either Epstein-Barr virus (EBV)-infected B cells or activated monocytes promote the proliferation of EBV-infected B cells and permit their growth at low cell densities. This suggests that growth factors are important for B-cell immortalization by EBV. In this study, a monocyte-derived factor that promotes the growth of EBV-infected b cells was purified and identified as interferon-beta 2 (IFN-beta 2), which is also known as 26-kilodalton protein, B-cell differentiation factor (BSF-2), and interleukin-6 (IL-6). The purified protein has a specific activity of approximately 4 X 10(7) units per milligram of protein in assays of B-cell growth. Thus, IFN-beta 2/BSF-2 is a B-cell growth factor that promotes the proliferation of human B cells infected with EBV.     

亚洲玉米螟幼虫血细胞对外源体的包囊

    亚洲玉米螟幼虫血细胞包囊具双相性.当DEAE-sephadex珠子被诱导进亚洲玉米螟幼虫的血腔内后,颗粒细胞首先在3 min内吸附到珠子表面,浆细胞随后吸附形成多层浆细胞层,注射48 h后最终形成重叠细胞层的平滑囊鞘.完整的囊鞘显示有3层明显不同的区域.颗粒细胞起着最初识别血腔中的外源体作用,一旦珠子被颗粒细胞识别为外源体,颗粒细胞将裂解释放一些公认的物质诱导浆细胞识别外源体,于是包囊被立刻启动.总之,研究结果显示亚洲玉米螟幼虫包囊明显依赖血细胞之间的互相合作.     

Liquid carbon, carbon-glass beads, and the crystallization of carbon nanotubes

The formation of carbon nanotubes in a pure carbon arc in a helium atmosphere is found to involve liquid carbon. Electron microscopy shows a viscous liquid-like amorphous carbon layer covering the surfaces of nanotube-containing millimeter-sized columnar structures from which the cathode deposit is composed. Regularly spaced, submicrometer-sized spherical beads of amorphous carbon are often found on the nanotubes at the surfaces of these columns. Apparently, at the anode, liquid-carbon drops form, which acquire a carbon-glass surface due to rapid evaporative cooling. Nanotubes crystallize inside the supercooled, glass-coated liquid-carbon drops. The carbon-glass layer ultimately coats and beads on the nanotubes near the surface.     

Red cells coated with immunoglobulin G: binding and sphering by mononuclear cells in man

Human monocytes, macrophages, and certain lymphocytes bind firmly to red cells coated with immunoglobulin G, whether or not it is acting as antibody. Monocyte binding is specific for cells coated with immunoglobulin G and is inhibited specifically by this immunoglobulin or its Fc-fragment in solution. Although not involving serum complement and not usually a prelude to erythrophagocytosis, this binding causes rapid morphological injury to red cells, as manifested by their sphering, increased osmotic fragility, deformation, and fragmentation. It is inferred that mononuclear cells have specific surface receptors for immunoglobulin G and that these provide a critical phase of the mechanism in vivo, whereby red cells or other particles coated with antibody are apprehended and destroyed.     

内包粉末活性炭凝胶球去除苯酚

研究了不同包埋材料包埋的粉末活性炭凝胶球在中性条件下对苯酚和腐殖酸的吸附效率和苯酚的吸附等温线。结果表明:内包粉末活性炭凝胶球对苯酚的吸附等温线符合Freundlich方程,以海藻酸钠,聚乙烯醇海藻酸钠为包埋材料的凝胶球吸附苯酚的性能优于经缩醛反应后的聚乙烯醇海藻酸钠为包埋材料的凝胶球。凝胶球减少了粉末活性炭对水体中腐殖物质的吸附,添加聚乙烯醇增加了凝胶球的机械强度,不易粘连。添加戊二醛进行缩醛反应使得凝胶球网状结构致密,导致吸附苯酚能力下降,但不吸附腐殖酸,具有选择性吸附的性质。     

Phagocytized platelets: a source of lipids in human thrombi and atherosclerotic plaques

Phagocytosis of lipid-rich platelets by monocytes and the transformation of such cells into lipophages containing fat was observed in human thrombi. The lipophages are similar to lipophages in atherosclerotic plaques. This observation supports the idea that some atherosclerotic plaques are organized mural thrombi.     

A clonogenic bone marrow progenitor specific for macrophages and dendritic cells

Macrophages and dendritic cells (DCs) are crucial for immune and inflammatory responses and belong to a network of cells that has been termed the mononuclear phagocyte system (MPS). However, the origin and lineage of these cells remain poorly understood. Here, we describe the isolation and clonal analysis of a mouse bone marrow progenitor that is specific for monocytes, several macrophage subsets, and resident spleen DCs in vivo. It was also possible to recapitulate this differentiation in vitro by using treatment with the cytokines macrophage colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. Thus, macrophages and DCs appear to renew from a common progenitor, providing a cellular and molecular basis for the concept of the MPS.     

Contact-mediated bone resorption by human monocytes in vitro

Human circulating monocytes in tissue culture are capable of resorbing devitalized adult and fetal bone. An important component of this process is the adhesion of the cells to the mineralized substrate and the localized removal of matrix from beneath the attached cells. The process appears to involve both release of lysosomal enzymes onto the substrate and intracellular accumulation (transport) of resorbed matrix.     

Thermographic selection of effective catalysts from an encoded polymer-bound library

A general method is introduced for the rapid and simultaneous evaluation of each member of large encoded catalyst libraries for the ability to catalyze a reaction in solution. The procedure was used to select active catalysts from a library of potential polymer-bound multifunctional catalysts. From approximately 7000 beads screened (3150 distinct catalysts), 23 beads were selected for catalysis of an acylation reaction. Kinetic experiments indicate that the most strongly selected beads are also the most efficient catalysts.     

Chromatin-independent nuclear envelope assembly induced by Ran GTPase in Xenopus egg extracts

The nuclear envelope (NE) forms a controlled boundary between the cytoplasm and the nucleus of eukaryotic cells. To facilitate investigation of mechanisms controlling NE assembly, we developed a cell-free system made from Xenopus laevis eggs to study the process in the absence of chromatin. NEs incorporating nuclear pores were assembled around beads coated with the guanosine triphosphatase Ran, forming pseudo-nuclei that actively imported nuclear proteins. NE assembly required the cycling of guanine nucleotides on Ran and was promoted by RCC1, a nucleotide exchange factor recruited to beads by Ran-guanosine diphosphate (Ran-GDP). Thus, concentration of Ran-GDP followed by generation of Ran-GTP is sufficient to induce NE assembly.     

铜鱼、圆口铜鱼和长鳍吻鮈外周血细胞显微观察

[目的]为鱼类血液学研究积累资料,同时为进一步驯养提供借鉴。[方法]对29尾铜鱼、27尾圆口铜鱼和17尾长鳍吻的尾静脉取血,常规方法每尾制作血涂片2-5张,Gimesa和Wright染液联合染色,Nikon—DXM1200数码显微摄影系统观察和拍照,ImageProplus软件随机测量各类血细胞。[结果]观察到红细胞、嗜中性粒细胞、单核细胞、淋巴细胞和血栓细胞5种血细胞;红细胞有直接分裂现象;成红细胞有2种类型,单核细胞呈不规则球形,淋巴细胞有“大”、“小”2型。[结论]共有5种血细胞,无嗜碱和嗜酸性粒细胞;“大”、“小”2型淋巴细胞并无定量区别;各种血细胞单核细胞最少,血栓细胞最多。     

Optimization of technological practices for rice cultivation under the conditions in Dagestan

On meadow-chestnut heavy clay soil of Dagestan plains, the advantage in row method of rice sowing by seed drill SZ-3.6, whose coulters are reequipped with limiters of seed depth covering—beads—has been discovered. Use of the coulters equipped with conical beads ensures stable in depth movement of drill and qualitative covering of seeds into a compact bed.     

Prostacyclin synthesis induced in vascular cells by interleukin-1

Supernatants from cultures of human monocytes that had been stimulated with endotoxin or silica induced the synthesis of prostacyclin in endothelial and smooth muscle cells. The lymphokine mediating these effects on the cells of the blood vessel wall was identified as interleukin-1; interferons and interleukin-2 were inactive. Interleukin-1-induced prostacyclin synthesis represents a new aspect of the interaction between the immune system (as well as other tissues) and the vessel wall and may serve as a basis for the development of new strategies in antithrombotic therapy.