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X M Tang

Publications and source records attributed to X M Tang.

72 records · Page 4Linked to original sources
PubMed1985

Glycoprotein synthesis in the Golgi apparatus of spermatids during spermiogenesis of the rat.

During steps 1-7 of spermiogenesis the Golgi apparatus contributes to the formation of the acrosomic system which develops at the surface of the nucleus. Later, in step 8, the Golgi apparatus detaches from the acrosome and remains suspended in the elongated cytoplasm until it degenerates during step 16. Using 3H-fucose as a tracer and the radioautographic technique, we observed that the Golgi apparatus incorporates the tracer and delivers the labeled glycoproteins to the developing acrosomic system during steps 1-7 of spermiogenesis, to multivesicular bodies during steps 1-9, and to the remaining cytoplasm and plasma membrane during steps 1-15. Throughout these steps of spermiogenesis the Golgi apparatus does not show major changes in structure; it is composed of a cortex made up of connected stacks of saccules and a medulla showing a loose aggregate of vesicular profiles. Glycoprotein synthesis in this Golgi apparatus, before and after it contributes lysosomal glycoproteins to the growing acrosomic system, was quantitatively assessed in electron microscope EM radioautographs of tissue sections from animals sacrificed at 1, 4, 8, and 24 h of 3H-fucose injection. The incorporation of the labeled sugar was found to remain quantitatively similar during steps 1-15 of spermiogenesis, and therefore, no shift in glycoprotein synthesis took place following separation of the Golgi apparatus from the acrosomic system. Throughout these steps, fucose molecules are first incorporated in the cortex of the organelle and subsequently transported to the medulla, where they temporarily accumulate before being delivered, depending on the step of spermiogenesis, to the acrosomic system, to the multivesicular bodies, and also, presumably, to the plasma membrane.

Animals↗
PubMed1984

Glycoprotein synthesis in Sertoli cells during the cycle of the seminiferous epithelium of adult rats: a radioautographic study.

Glycoprotein synthesis in Sertoli cells was investigated in rats sacrificed at various intervals (10, 30 min; 1, 4, 8, 24 h) after a single intratesticular injection of [3H] fucose. Thin sections of glutaraldehyde-fixed testes were radioautographed and the relative concentration of the label over the various cytoplasmic components of the Sertoli cells was analyzed quantitatively from electron microscopic photographs. The analysis was performed at the various stages of the cycle of the seminiferous epithelium grouped as follows: I-IV, V-VII, VIII-XI, XII-XIV. The incorporation of [3H] fucose into glycoproteins took place initially in the Golgi apparatus of the cells and the labeled glycoproteins later migrated to the lysosomes and plasma membrane. The corrected grain counts over the various cytoplasmic components of the Sertoli cell at various intervals after [3H] fucose injection, indicated that the synthesis of glycoproteins detected by radioautography after [3H] fucose injection was constant during the cycle of the seminiferous epithelium. Furthermore, the rate of transfer of the labeled glycoproteins from the Golgi apparatus to the lysosomes and plasma membrane was also noncyclic.

Animals↗
PubMed1982

A cytochemical study of the Golgi apparatus of the spermatid during spermiogenesis in the rat.

The reactivity of the various components of the Golgi apparatus of rat spermatids for three phosphatase activities (nicotinamide adenine dinucleotide phosphatase, NADPase; thiamine pyrophosphatase, TPPase; cytidine monophosphatase, CMPase) and the incorporation of 3H-fucose by the spermatids was analyzed at the 19 steps of spermiogenesis, i.e., during and after this organelle elaborated the glycoprotein-rich acrosomic system. During steps 1-3, the Golgi apparatus produced, in addition to the proacrosomic granules, multivesicular bodies that became associated with the chromatoid body. NADPase was located within the four of five intermediate saccules of Golgi stacks, and TPPase was found in the last one or two saccules on the trans aspect of the stacks from steps 1 to 17 of spermiogenesis. CMPase was located within the thick saccular GERL elements found in the trans region of the Golgi apparatus from steps 1 to 7 of spermiogenesis, but the CMPase-positive GERL disappeared from the Golgi apparatus after its detachment from the acrosomic system at step 8. Th acrosomic system itself was reactive from CMPase and TPPase but was negative for NADPase, while the multivesicular bodies were CMPase and NADPase positive but unreactive for TPPase. Tritiated-fucose was readily incorporated within the Golgi apparatus of steps 1-17 spermatids; in steps 1-7 it was subsequently incorporated within the acrosomic system and multivesicular bodies. These various data indicated (1) that the Golgi apparatus of spermatids, although it loses its CMPase-positive GERL element in step 8, retains evidence of functional capacity until it degenerates in step 17; (2) that in early spermatids the various saccular components of the Golgi are specialized with respect to enzymatic activities; and (3) that each Golgi region may contribute in a coordinated fashion to the formation of the acrosomic system and multivesicular bodies.

Animals↗
PubMedDate not supplied

Origin and fate of autophagosomes in Leydig cells of normal adult rats.

Autophagosomes were observed frequently in electron microscope photographs of Leydig cells from normal adult rat testis. Their formation, evolution and fate were analyzed morphologically in preparations treated to show cytidine monophosphatase (CMPase) and glucose-6-phosphatase (G-6-Pase) activities and in animals sacrificed at various time intervals ranging from 5 min to 6 hrs after a single intratesticular injection of cationic ferritin. Analysis of the morphologic data led to the following interpretation and model. Preautophagosomal structures appeared as flattened, elongated membranous profiles. These expanded, took on a C-shape and fused at their edges to demarcate a small cytoplasmic territory containing normal-looking smooth endoplasmic reticulum (ER) and mitochondria. Such early autophagosomes were thus delimited by two membranes separated by a narrow lumen. Following fusion of these elements with secondary lysosomes, the space between the two membranes increased in size, the inner membrane disintegrated and the enclosed organelles no longer could be identified. The late autophagosomes then reached the cell surface and appeared to exocytose their residual content. In contrast to secondary lysosomes and trans-Golgi elements, which were CMPase-positive, the preautophagosomal flattened membranous elements and early autophagosomes were CMPase-negative. The late autophagosomes on the contrary were CMPase-positive. While ER cisternae were G-6-Pase-positive, the pre-, early and late autophagosomal structures were unreactive for this enzyme. Cationic ferritin tracer experiments showed that only late autophagosomes became labeled with cationic ferritin following their fusion with secondary lysosomes into which the tracer had accumulated following its endocytosis from the cell surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Manipulating biological samples for environmental scanning electron microscopy observation.

Biological samples having different characteristics were observed by environmental scanning electron microscopy (ESEM). The environmental conditions for untreated biological samples was determined by optimizing sample temperature and chamber pressure. When the temperature was at 4 degrees - 6 degrees C and chamber pressure was 5.2-5.9 Torr, the relative humidity in the specimen chamber was about 85%. Under these conditions, the surface features of the sample were completely exposed and did not exhibit charging. The images obtained from the untreated samples at different ESEM conditions were also compared with fixed and coated samples observed under high vacuum.

Animals↗
PubMedDate not supplied

Surgical glove powders differentially modulate macrophage and lymphocyte-derived cytokines and eicosanoids production in vitro.

The objective of the present study was to determine the effect of surgical glove powders Biosorb, Keoflo, and CaCO(3) and Hydrocote (a powder-free film; Biogel) on cytokine and eicosanoid production by lipopolysaccharide/phorbol 12-myristate 13-acetate activated and unactivated HL60, U937, and RPMI 1788 cells, human monocyte/macrophage, and B lymphocyte cell lines. The unactivated cell culture-conditioned media contained a low level of interleukin-1alpha and -1beta, granulocyte macrophage colony stimulating factor, and tumor necrosis factor-alpha, which significantly increased after activation (p < 0.05). Exposure of unactivated cells to glove powders or Hydrocote (100 microg/ml) had little effect. However, these compounds appeared to have multiple inhibitory and stimulatory action on the production of these cytokines and eicosanoids in lipopolysaccharide/phorbol 12-myristate 13-acetate activated cells. For instance, granulocyte macrophage colony stimulating factor production was inhibited only in U937 cells by Keoflo and CaCO(3), whereas, tumor necrosis factor-alpha production was stimulated by Biosorb and Keoflo in HL-60, and CaCO(3) was found to be predominantly inhibitory on tumor necrosis factor-alpha production by these cells (p < 0.05). Total transforming growth factor-beta(1) production was stimulated by Biosorb and Hydrocote in U937 and HL-60 cells, respectively, but inhibited by Keoflo in U937 cells. However, Biosorb and Keoflo inhibited transforming growth factor-beta(1) production in both HL-60 and RPMI 1788 cells, without any effect on active transforming growth factor-beta(1). With regard to eicosanoids, Biosorb and Keoflo stimulated prostaglandin E(2) production by RPMI 1788 cells, whereas it was inhibited by all glove powders in HL-60 cells. Thromboxane B(2) production was stimulated by Keoflo and inhibited by CaCO(3) and Hydrocote in U937 cells. Finally, Leukotriene B(4) synthesis was found to become stimulated by Keoflo, CaCO(3), and Hydrocote in both HL60 and RPMI 1788 cells (p < 0.05). These data indicate that exposure of activated, but not unactivated, macrophages and lymphocyte to surgical glove powders and Hydrocote differentially effects the release of cytokines and eicosanoids by these cells. Considering that cytokines and eicosanoids play an important role in mediating the inflammatory and immune responses of wound healing, complications arising from glove powder exposure in vivo may involve mechanisms which alter the type and level of cytokine and eicosanoid production.

Journal Article↗
PubMedDate not supplied

Postsurgical intraperitoneal exposure to glove powders modulates inflammatory and immune-related cytokine production.

The objective of the present study was to determine whether intraperitoneal exposure to glove powders modulates the inflammatory and immune responses by altering the influx of inflammatory and immune cells and peritoneal fluid cytokines and thus the outcome of surgically induced peritoneal wound healing. Peritoneal wall injuries were made by scraping the tissue until bleeding occurred in 360 mice. One of the following fluids was then introduced into the peritoneal cavity: phosphate-buffered saline solution, phosphate-buffered saline solution containing glove powders (Biosorb and Keoflo, 100 microg/ml), Hydrocote (Hydrogel film, Biogel 100 microg/ml), latex proteins (1 mg/ml), or lipopolysaccharides (12.5 microg/ml). At intervals of 1 to 28 days after injury, 10 mice per treatment per day and 10 uninjured mice were killed, peritoneal fluids were collected to determine the cytokine levels, the rate of fibrous adhesions formed at the site of injuries was graded, and peritoneal walls with attached fibrous adhesions were removed to determine the degree of inflammatory and immune cell infiltration into the wound. The results indicated that, with the exception of interferon-gamma, the peritoneal fluid levels of transforming growth factor-beta1, tumor necrosis factor-alpha, interleukin-1beta, and granulocyte-macrophage-colony stimulating factor in the phosphate-buffered saline solution-treated injured group significantly increased, reaching maximum between days 4 and 7 (p < 0.05) compared with the uninjured group and returned to uninjured values by day 14 after injury. The level of transforming growth factor-beta1 was higher in glove powders and Hydrocote-treated groups than in latex, lipo-saccharides, or phosphate-buffered saline solution-treated groups until day 14 after surgery (p < 0.05). The levels of tumor necrosis factor-alpha and interleukin-1beta increased in all treatment groups during the first week after injury compared with uninjured controls, with the exception of Hydrocote. The number of T helper/inducers (CD4), total leukocytes (CD11a), B lymphocytes (CD45R), granulocytes (Gr-1), and mononuclear phagocytes (Mac-3) in the wound increased during the first week after peritoneal wounding with no significant difference between treated and untreated groups. The rate of adhesion formation was not significantly altered in treated compared with untreated groups. These data suggest that a mechanism which mediates glove powder-induced peritoneal inflammatory and immune reactions in the postsurgical setting involves augmentation of cytokine production without influencing the influx of inflammatory and immune cells or adhesion formation.

Journal Article↗