An entomopathogenic bacterium, Xenorhabdus nematophila, inhibits hemocyte phagocytosis of Spodoptera exigua by inhibiting phospholipase A(2)

Phagocytosis is a hemocytic behavior against bacterial infection. An entomopathogenic bacterium, Xenorhabdus nematophila, inhibits immune responses of target insects and causes hemolymph septicemia. This study analyzed how X. nematophila could inhibit phagocytosis to increase its pathogenicity. Granular cells and plasmatocytes were the main phagocytic hemocytes of Spodoptera exigua determined by observing fluorescence-labeled bacteria in the cytosol. X. nematophila significantly inhibited phagocytosis of both hemocytes, while heat-killed X. nematophila lost its inhibitory potency. However, co-injection of X. nematophila with arachidonic acid did not show any significant inhibition of hemocyte phagocytosis. In fact, hemocytes of S. exigua infected with X. nematophila showed significant reduction in phospholipase A(2) (PLA(2)) activity. Dexamethasone, a specific PLA(2) inhibitor, significantly inhibited phagocytosis of both cell types. However, the inhibitory effect of dexamethasone was recovered by addition of arachidonic acid. Incubation of hemocytes with benzylideneacetone, a metabolite of X. nematophila, inhibited phagocytosis in a dose-dependent manner. These results suggest that X. nematophila produces and secretes PLA(2) inhibitor(s), which in turn inhibit the phagocytic response of hemocytes.     

Thyromegaly secondary to simultaneous papillary carcinoma and histiocytosis X. Report of a case and review of the literature

The cytologic and histologic findings are reported in a case of papillary carcinoma arising within a thyroid gland pathologically enlarged by histiocytosis X. Fine needle aspiration (FNA) biopsies of a thyroid nodule in a patient with longstanding histiocytosis X produced a scanty amount of colloid, a moderately dense mixed inflammatory infiltrate and numerous small papillary fragments lined by cuboidal-to-columnar cells. Both the inflammatory cells and the epithelial cells showed nuclear grooves; the two populations of neoplastic cells were distinguished, and the correct diagnosis of the nodule was made, by recognizing the greater amount of granular cytoplasm of the mononucleated Langerhans' cells. The rare involve-of the thyroid by histiocytosis X is reviewed; this case, which appears to be the first reported instance of the co-occurrence of histiocytosis X and papillary carcinoma of the thyroid, indicates that patients with histiocytosis X should be observed for the development of thyroid carcinoma and that FNA biopsy can make the distinction between the two conditions.     

Lipogranulomatous lymphadenopathy as a potential source of error in fine needle aspiration cytology. A case report

BACKGROUND: Lipogranulomatosis refers to the presence, in lymph nodes and spleen, of lipid material arising from endogenous sources, such as tumors, hematomas, cholesterol deposits, fat embolism and fat necrosis. The histologic image is similar to that seen in lymph nodes after lymphography, with vacuolized histiocytes; round, empty spaces; and numerous multinucleated giant cells (MGC). CASE: A 27-year-old woman was referred to our department for fine needle aspiration of bilateral inguinal lymph nodes. One year before, a giant cell tumor of the sacrum was surgically excised at another medical center. The aspirated material showed a normal lymphoid cell background in addition to several MGC and ill-defined cellular groups of mononuclear, histiocytelike cells admixed with mature lymphocytes. After the cytologic report was issued both nodes were surgically excised. The most remarkable histologic finding was the presence of sinus histiocytosis and multifocal subcapsular and sinusoidal lipogranulomas with numerous MGC. CONCLUSION: Lipogranulomatous lymphadenopathy is a rare pathologic condition and may be responsible for smears with numerous MGC. This entity should be considered when evaluating lymph node aspirates from patients with neoplasia, particularly that with a giant cell component.     

The paracortical area in reactive lymph nodes demonstrating sinushistiocytosis

The enzyme and immunohistochemical features of lymphnodes showing sinus histiocytosis have been studied. Sinus histiocytes with phenotype OKM1+ OKT4+ Leu3a+ To5+ OKIal- showed strong acid phosphatase and non-specific esterase, weak endogenous peroxidase and no ATPase activities. In nine out of ten lymph nodes, paracortical collections of dendritic OKT6+ OKIal+ cells were observed. In two of the four cases studied these dendritic cells showed strong ATPase activity. We suggest that the dendritic OKT6+ OKIal+ ATPase+ interfollicular cells represent newly arrived veiled cells (VC) which have entered the lymph node by the afferent lymph, settled in the interfollicular area and are probably involved in the induction of a cellular immune response. OKT6+ OKIal+ ATPase+ VC may subsequently transform into mature, OKT6- OKIal+ ATPase+ interdigitating reticulum cells which are involved in the negative feedback of the cellular immune response. The association with sinus histiocytosis is probably related to the fact that an increase in mononuclear phagocytes in the afferent lymph is accompanied by a relative increase in VC. Our results demonstrate that in lymph nodes showing sinus histiocytosis, two cell types increase in number, i.e. an Ia- sinusoidal cell, engaged in phagocytosis of foreign material, and an Ia+ dendritic cell in the interfollicular area, probably involved in the induction of a cellular immune response.     

Morphology and Round Body Formation in Vibrio marinus

The morphology of Vibrio marinus MP-1 was studied by phase and electron microscopy. The ultrastructure of the vibrio form of V. marinus was found to be typically gram-negative with a trilaminar plasma membrane and cell wall. The coccoid or round bodies noted in otherwise pure cultures of V. marinus were frequently found in early and late stationary phase of growth. The round bodies in ultrathin section were found to contain at least one, and often three or four, cell units. Three types of round bodies were observed in ultrathin section, each differing in size and behavior: "spherules," "spheres" or the "round body," and "giant cells" or "macrospheres." The round bodies appeared to be associated with, or to result from, the constrictive cell division of V. marinus.     

A comparison of the effects of different substrata on chondrocyte morphology and the synthesis of collagen types IX and X

Summary Embryonic chick sternal chondrocytes were cultured either within three dimensional gels of type I collagen, type II collagen or agar, or as monolayers on plastic dishes coated with air-dried films of these matrix macromolecules. It was observed that cell shape and cell growth varied markedly between the different culture conditions. Flattened monolayers of cells on plastic or films of type I or type II collagen, proliferated more rapidly and reached a higher final cell density per culture than the more rounded cells found in the cultures on agar films or within three-dimensional gels. Biosynthetic studies demonstrated that in addition to the synthesis of type II collagen, all the cultures were producing collagen types IX and X. Chondrocytes cultured on plastic or films of the different matrix macromolecules all showed a similar expression of types IX and X collagen, independent of whether they displayed a flattened or round cell morphology. In contrast, marked variations in the proportions of the minor collagens, particularly type X collagen, were observed when the cells were cultured within three-dimensional gels. The data suggest that direct interaction of the cell surface with matrix constituents displaying a particular spatial array could be an important aspect in the control of type IX and X collagen expression by chondrocytes. The financial support of the Arthritis & Rheumatism Council and the Medical Research Council is gratefully acknowledged.     

Lectin binding and inhibition studies reveal the importance of D-glucose, D-mannose and N-acetylglucosamine during early sexual development of Dictyostelium discoideum

Fluorescein-conjugated and non-conjugated lectins were used to determine which surface sugars are involved in the early events of sexual (macrocyst) development in Dictyostelium discoideum. Only zygote giant cells showed unique binding of FITC-WGA and FITC-PNA while all cell types (amoebae, gametes, binucleates, giant cells) showed identical patterns of FITC-Con A, -Gorse and -RCA II binding. In spite of its non-selective labelling of all cell types, Con A inhibited macrocyst formation. The temporal addition of Con A with and without specific hapten sugars indicates the importance of both D-mannose and D-glucose in phagocytosis and, possibly, cell fusion. WGA also inhibited macrocyst formation. Varying the time of addition of the lectin plus/minus its primary hapten sugar implicates N-acetylglucosamine as being important in cell fusion. Neither Gorse, RCA II nor PNA had any detectable inhibitory effects on macrocyst development leaving the appearance of increased PNA receptors at the giant cell surface as an enigma.     

Rat retinal pigment epithelial cells show specificity of phagocytosis in vitro

The retinal pigment epithelial (RPE) cell of the eye normally phagocytozes only retinal rod outer segments (ROS). The specificity of this phagocytic process was examined by incubating RPE cells with a variety of particle types. Confluent RPE cell cultures were incubated for 3 h at 37 degrees C in the presence of rat ROS, rat red blood cells (RBC), algae, bacteria, or yeast. Other cell cultures were incubated with equal numbers of ROS and one other particle type. Quantitative scanning electron microscopy was used to determine the numbers and morphology of particles bound to RPE cells, while double immunofluorescence labeling (Chaitin, M. H., and M. O. Hall, 1983, Invest. Ophthalmol. Vis. Sci., 24:812-820) was used to quantitate particle binding and ingestion. Both assays demonstrated phagocytosis to be a highly specific process. RPE cells bound 40-250 X more ROS than RBC, 30 X more ROS than algae, and 5 X more ROS than bacteria or yeast. Ingestion was more specific than binding; RPE cells ingested 970 X more ROS than RBC, 140 X more ROS than bacteria, and 35 X more ROS than yeast. The phagocytic preference for ROS was maintained in competition experiments with other particle types. Serum was found to be essential for phagocytosis. This study demonstrates that both the binding and ingestion phases of phagocytosis are highly specific processes.     

过表达IL-12调节单核系肿瘤细胞向巨噬细胞分化

构建过表达白细胞介素-12（interleukin-12,IL-12）的THP-1单核系肿瘤细胞模型,从形态学、巨噬细胞表面标志表达水平及吞噬功能3方面探究过表达IL—12能否调节单核系肿瘤细胞向巨噬细胞分化。结果发现,与空白和空载组相比,IL-12组的THP．1细胞界限不明显,散在细胞增多;呈圆形或不规则圆形,偶见毛刺状突起;核仁模糊或消失,核染色质条索状浓集;CD68mRNA和蛋白表达量均升高俨〈0．05）。与空白组相比,CDllbmRNA和蛋白表达量升高不明显俨〉O．05）,但72hCD11b蛋白表达量明显高于相同培养条件下的空载组（P〈O．05）。培养72h后各组细胞吞噬能力比较,IL-12组吞噬率（36．7±1．2）％高于空白组（15．7±3．1）％和空载组（28．O±1．5）％,差异有统计学意义（P〈0．05）。上述结果提示,过表达IL-12可以促进单核系肿瘤细胞向巨噬细胞分化。     

Anti-Leu-3/T4 antibodies react with cells of monocyte/macrophage and Langerhans lineage

Anti-Leu-3a, anti-Leu-3b, OKT4, and anti-T4 murine monoclonal antibodies react with a membrane component expressed by mature peripheral blood helper T cells and certain thymocyte subsets. Using a variety of immunologic staining techniques, we have demonstrated the reactivity of these antibodies with other cell types. Normal and neoplastic cells of monocyte/macrophage lineage bear the Ia+/Leu-6-/Leu-3+ phenotype, whereas histiocytosis X cells bear the Ia+/Leu-6+/Leu-3+ phenotype. The Ia+/Leu-6- cells of malignant histiocytosis and the Ia+/Leu-6+ epidermal Langerhans cells were variably Leu-3+. Normal monocyte/macrophage reactivity with anti-Leu-3/T4 appears to be primarily intracytoplasmic, whereas on U937 monocyte tumor cells, marked membrane reactivity is also observed. These results strongly suggest that certain cells other than helper T cells and thymocytes can express and, at least in some cases, synthesize a component previously regarded as T-lineage specific.     

Endocrine cells in the gastric mucosa of elasmobranch fishes. An ultrastructural study

The endocrine cells of gastric mucosa of two elasmobranch species were studied by light and electron microscopy. Five cell types were identified in the fundic mucosa, four of which are of "open type". All of them show pleomorphic granules of variable size, except those of the type V cell which are round in shape and of comparatively small diameter. Six different cell types are found in the pyloric mucosa, all of "open type" except for type XI cells which appear to be "closed". Pyloric types VIII, IX, X and XI cells show similar structural characteristics as fundus types I, V, II and IV respectively. Silver impregnation was also used at both light and electron microscopical levels. No functional classification or analogies with other vertebrate gastric endocrine cells were attempted as these would be too speculative on the basis of ultrastructural characteristics only.     

Effects of Lactobacillus strains on cancer cell proliferation and oxidative stress in vitro

AIMS: The objective of this study was to assess in vitro, whether heat-killed (HK) lactic acid bacteria cells and fractionations of HK cells could suppress the viability of human cancer cells and inhibit the cytotoxicity associated with oxidative stress. METHODS AND RESULTS: Among the strains, the HK cells of Lactobacillus acidophilus 606 and Lactobacillus casei ATCC 393 exhibited the most profound inhibitory activity in all of the tested cell lines. HK cells of L. acidophilus 606 were determined to be less toxic to healthy human embryo fibroblasts (hEF cells) than were HK cells of L. casei ATCC 393. The soluble polysaccharides from L. acidophilus 606 evidenced the most effective anticancer activity, but inhibited hEF cell growth by only 20%. The soluble polysaccharides from L. acidophilus 606 were partly observed to induce apoptosis in the HT-29 cells by DNA fragmentation and propidium iodine staining. Both the HK cells of L. acidophilus 606 and the soluble polysaccharide components of this strain also exhibited potent antioxidative activity. CONCLUSIONS: Our findings suggest that the soluble polysaccharide fraction from L. acidophilus 606 may constitute a novel anticancer agent, which manifests a high degree of selectivity for human cancer cells and antioxidative agent in the food industry. SIGNIFICANCE AND IMPACT OF THE STUDY: These soluble polysaccharide components from Lactobacillus may be applied to various foods, and used as adjuncts for cancer therapy and prevention.     

The differentiation of monocytes into macrophages,epithelioid cells,and multinucleated giant cells in subcutaneous granulomas

The morphological changes occurring in monocytes during their differentiation into macrophages, epithelioid cells, Langhans-type giant cells, and foreign-body-type giant cells were investigated in foreign-body granulomas induced by subcutaneous implantation of pieces of Melinex plastic. Analysis based on Adams's (1974) criteria for discrimination between the several types of cell of the monocyte line, showed that each type has a characteristic type of granule. Primary and secondary granules, numerous in the Golgi area of monocytes were generally found close to the cell membrane and decreased in number in maturing macrophages. This was accompanied by an increase in the number of microtubules. Mature macrophages show numerous characteristic macrophage granules, which are round (average diameter: 280 nm) and have a halo between the limiting membrane and granular matrix. Mature epithelioid cells have characteristic epithelioid cell granules, and multinucleated giant cells a heterogenous population of granules. Fusing macrophages generally have their Golgi areas facing each other, and also show a reduced thickness of the cell coat. The morphology of the multinucleated giant cell is closely related to the number of nuclei present. In Langhans-type giant cells, which generally have two to ten nuclei, a giant centrosphere with numerous aggregated centrioles is found. In transition forms between Langhans-type and foreign-body-type giant cells, which generally contain 10--30 nuclei, the centrioles show less aggregation. In the foreign-body-type giant cells, which generally have more than 30 nuclei, centrioles are virtually absent and never aggregated. These differences between the Langhans-type giant cells, the foreign-body-type giant cells, and the transition forms, support our previous finding that Langhans-type giant cells are the precursors of foreign-body-type giant cells.     

Monoclonal antibody against histiocytosis X cells.

Monoclonal antibody against histiocytosis X cells (HXCs) was established. The antigen was the cell membrane of HXCs from the submandibular lesion of a 63-year-old man who had been diagnosed as an adult type of histiocytosis X (HX) and whose HXCs had numerous Birbeck granules (BGs). The obtained monoclonal antibody, named MI1, reacted with the antigenic cell membrane of HXC. Immunoblotting showed that MI1 bound to the cell membrane of 28500 mw. MI1 also reacted with interdigitating reticulum cells (IDCs) in the tonsil and Langerhans cells (LCs) in the epidermis. MI1 reacted with the BGs which connected to the cell membrane, but not with those located near the nucleus.     

Regulation of Cell Volume by Active Cation Transport in High and Low Potassium Sheep Red Cells

A model cell which controls its cation composition and volume by the action of a K-Na exchange pump and leaks for both ions working in parallel is presented. Equations are formulated which describe the behavior of this model in terms of three membrane parameters. From these equations and the steady state concentrations of Na, K, and Cl, values for these parameters in high potassium (HK) and low potassium (LK) sheep red cells are calculated. Kinetic experiments designed to measure the membrane parameters directly in the two types of sheep red cells are also reported. The values of the parameters obtained in these experiments agreed well with those calculated from the steady state concentrations of ions and the theoretical equations. It is concluded that both HK and LK sheep red cells control their cation composition and volume in a manner consistent with the model cell. Both have a cation pump which exchanges one sodium ion from inside the cell with one potassium ion from outside the cell but the pump is working approximately four times faster in the HK cell. The characteristics of the cation leak in the two cell types are also very different since the HK cells are relatively more leaky to sodium as compared with potassium than is the case in the LK cells. Both cell types show appreciable sodium exchange diffusion but this process is more rapid in the LK than in the HK cells.     

多核巨细胞形成中的“核有丝分裂”

多核巨细胞的形成,除出合并和核的直接分裂的二个方式外,也可由"核有丝分裂"的方式来形成的,本文报告了这种核有丝分裂的多核巨细胞的一些例子。此外还有一种染色体很多,有近乎多元体的巨细胞,可能是进行核有丝分裂时,各个核的染色体相互混和的结果,最后是否能成为多元体细胞,目前尚未能证实。     

Comparative study on peroxidatic activity in inflammatory cells on cutaneous and peritoneal implants

Summary Inflammatory reactions were evoked by simultaneous implantation of pieces of Melinex plastic in the subcutaneous tissues of the dorsum and in the peritoneal cavity of rats. The cellular composition of the Melinex-adherent cells and their peroxidatic (PO) activity were investigated in relation to the duration of implantation. Several striking differences were found between the subcutaneous and peritoneal implants. On the 7th and 14th days, multinucleated giant cells were abundantly present on the subcutaneous implants, whereas they were relatively rare on the peritoneal implants. The subcutaneous implants bore no mast cells and only a few eosinophilic granulocytes, but both types of cell were observed frequently on the peritoneal implants.Macrophages and multinucleated giant cells on the subcutaneous implants show PO activity only in the granules or are PO negative. On the peritoneal implants three types of macrophages can be distinguished: exudate macrophages which have PO activity restricted to granules or are PO-negative; macrophages with PO activity in granules and both the rough endoplasmic reticulum (RER) and nuclear envelope; and resident macrophages with PO activity only in the RER and nuclear envelope. In addition, two types of multinucleated giant cells are found, one with and the other without PO activity in the RER and nuclear envelope. Multinucleated giant cells with PO activity in the RER and nuclear envelope as well as exudate macrophages with PO activity in the RER and nuclear envelope were mainly found 32 h and 3 days after implantation of the Melinex in the peritoneal cavity. These findings are discussed in the light of current knowledge of the PO activity in macrophages and multinucleated giant cells. It is concluded that the appearance of PO activity in the RER and nuclear envelope of exudate macrophages and multinucleated giant cells is in all probability a transient phenomenon, and that there is no objective evidence to support the opinion that exudate macrophages with PO activity in the RER and nuclear envelope are transitional cells between exudate and resident macrophages.     

Neutrophilic phagocytosis by tumor cells. A feature to consider in the differential diagnosis in fine needle aspiration smears

OBJECTIVE: To analyze neutrophilic phagocytosis by tumor cells in fine needle aspirate (FNA) smears from different types of tumor. STUDY DESIGN: A retrospective review of a total of 7 cases showing prominent neutrophilic phagocytosis by tumor cells in FNA smears during the period July 2003-December 2004. RESULTS: This feature was seen in malignant fibrous histiocytoma and poorly differentiated renal cell carcinoma in addition to giant cell carcinoma of the lung. CONCLUSION: Neutrophilic phagocytosis by tumor cells is seen in FNA smears and on cytomorphology. The differential diagnoses should include both pleomorphic sarcomas and carcinomas.     

Stem-like and non-stem human pancreatic cancer cells distinguished by morphology and metastatic behavior

We report here that XPA1 human pancreatic cancer cells are dimorphic. After injection in the spleen, XPA1 cells isolated from the primary tumor in the spleen were predominantly round; while cells isolated from the resulting liver metastasis and ascites were comprised of both round- and spindle-shaped cell types. Cancer cells previously grown in the spleen and re-implanted in the spleen developed large primary tumors in the spleen only. Cancer cells isolated from liver metastasis and re-transplanted to the spleen resulted in a primary tumor in the spleen and liver metastasis. Cancer cells derived from ascites and re-transplanted to the spleen developed primary tumors in the spleen and distant metastasis in the liver, lung, and diaphragm in addition to ascites formation. Spindle and round cells were differentially labeled with fluorescent proteins of different colors. After co-injection of the two cell types in the spleen, cells were isolated from the primary tumors, liver metastasis, and ascites and analyzed by color-coded fluorescence microscopy and fluorescence-activated cell sorting (FACS). No significant differences between the percentages of spindle-shaped and round cancer cells in the primary tumor and the liver metastasis were observed. However, spindle-shaped cancer cells were enriched in the ascites. One hundred percent of the spindle-shaped and round cancer cells expressed CD44, suggesting that morphology and metastatic behavior rather than CD44 expression can distinguish the stem-like cells of the XPA1 pancreatic cancer cell line. The spindle-shaped cancer cells had the greater capability for distant metastasis and ascites formation, suggesting they are stem-like cells, which can be readily targeted for therapy.     

Microglial motility in the rat facial nucleus following peripheral axotomy

Microglial motility was studied in living mammalian brain tissue using infrared gradient contrast microscopy in combination with video contrast enhancement and time lapse video recording. The infrared gradient contrast allows the visualization of living cells up to a depth of 60 μm in brain slices, in regions where cell bodies remain largely uninjured by the tissue preparation and are visible in their natural environment. In contrast to other techniques, including confocal microscopy, this procedure does not require any staining or labeling of cell membranes and thus guarantees the investigation of tissue which has not been altered, apart from during preparation. Microglial cells are activated and increase in number in the facial nucleus following peripheral axotomy. Thus we established the preparation of longitudinal rat brainstem slices containing the axotomized facial nucleus as a source of activated microglial cells. During prolonged video time lapse recordings, two different types of microglial cell motility could be observed. Microglial cells which had accumulated at the surface of the slice remained stationary but showed activity of the cell soma, developing pseudopods of different shape and size which undulated and which were used for phagocytosis of cell debris. Microglial phagocytosis of bacteria could be documented for the first time in situ. In contrast, ameboid microglia which did not display pseudopods but showed migratory capacity, could be observed exclusively in the depth of the tissue. Some of these cells maintained a close contact to neurons and appeared to move along their dendrites, a finding that may be relevant to the role of microglia in “synaptic stripping”, the displacement of synapses following axotomy. This approach provides a valuable opportunity to investigate the interactions between activated microglial cells and the surrounding cellular and extracellular structures in the absence of staining or labeling, thus opening a wide field for the analysis of the cellular mechanisms involved in numerous pathologies of the CNS.