Apical cytoplasm

About: Apical cytoplasm is a research topic. Over the lifetime, 1080 publications have been published within this topic receiving 36131 citations.

The expression and cellular localization of galectin-1 and galectin-3 in the Fallopian tube are altered in women with tubal ectopic pregnancy

Abstract: Galectin-1 and galectin-3 are abundantly expressed at implantation sites in the uterus, suggesting their involvement in the establishment of pregnancy. In this study, we examined the expression and localization of galectin-1 and galectin-3 in fallopian tubes from nonpregnant women, and in those presenting with tubal ectopic pregnancy. There was no significant difference in the expression of either galectin-1 (LGALS1) or galectin-3 (LGALS3) transcripts in the fallopian tube across the menstrual cycle. Their expressions in the fallopian tube were inversely correlated to each other (r = -0.5134, p < 0.0001) and differentially localized. Galectin-1 protein was abundant in the stroma of nonpregnant fallopian tubes, whereas galectin-3 was mainly localized to the epithelium, notably to the cilia of ciliated cells and the apical cytoplasm of secretory cells. In ectopic pregnancies, LGALS3 expression was significantly reduced (p < 0.0001), but LGALS1 expression did not change when compared to nonpregnant fallopian tubes collected during the mid-secretory phase. The percentage of fallopian tube epithelial cells expressing galectin-3 in cilia tended to be reduced (p = 0.0685), with an accompanying loss of a normal ciliary structure, while nuclear galectin-3 increased (p < 0.05) in ectopic pregnancies. Epithelial immunostaining for galectin-1 tended to be elevated in fallopian tubes from women with ectopic pregnancy. Coculture of human trophoblast origin SW71 cells significantly increased LGALS1 expression in human fallopian tube epithelial OE-E6/E7 cells, suggesting that trophoblast-derived products regulate LGALS1 expression in the oviductal epithelium. These findings imply a differential contribution of galectin-1 and galectin-3 in the homeostasis of human fallopian tubes and in the pathophysiology of ectopic pregnancy.

Ultrastructure of spermathecal epithelium of ctenolepisma longicaudata (insecta : thysanura)

Abstract: Summary The epithelial cells and their ultrastructural features of the Spermatheca of Ctenolepisma longicaudata have been described. In addition to the epithelial cells, both muscle and cuticular cells are also present in this organ. A variety of secretory vesicles and granules having lysosomal enzymes or mucoproteins is elaborated by the epithelial cells which are subsequently conducted to the apical cytoplasm for discharge in the lumen. Microtubules are involved in the direction of flow of secretory products. Besides, the cuticular and muscle cells of his organ of C. longicaudata make the latter exceedingly complicated for sperm storage, conduction and viability.

The Presence of Granular Excretory Ducts in the Rabbit Zygomatic Gland

Abstract: The proximal and interlobular ducts of rabbit zygomatic glands show a particular morphological feature consisting of numerous secretory granules localized in the apical cytoplasm of the cells. It is suggested that there is a similarity between these ducts and the granular ducts of submandibular glands in rodents.

Ultrastructure of the rhyncheal apparatus and other structures of the scolex of Grillotia (Christianella) carvajalregorum (Cestoda: Trypanorhyncha)

Abstract: The scolex ultrastructure was studied in Grillotia (Christianella) carvajalregorum (Cestoda: Trypanorhyncha) using histochemistry and transmission electron microscopy. We show for the first time the presence of scolex glands arranged in two longitudinal acini at the pars vaginalis parenchyma. These glands, along with those scattered in bothrial parenchyma, produce potentially adhesive glycoprotein secretions that are discharged via ducts to the bothrial grooves and apex. A particular type of sensory receptor was found around frontal gland pores, with a possible function in regulating their secretion activity. The internal structure of microtriches varies according to their morphotype and distribution on the scolex, this study providing the first description of the ultrastructure of serrate lanceolate spinitriches. The projections that form serrate margins are an extension of the medulla, differing from similar projections of other spinitriches. The large caps observed in serrate lanceolate spinitriches may reflect their specialization in attachment to and abrasion of intestinal mucosa, while the short caps and large bases of acicular filitriches may reflect their involvement in nutrient absorption. We also describe the rhyncheal apparatus ultrastructure, showing a similar basic structure of tentacular walls than that of other trypanorhynchs. Some differences among species in the number of fibrous layers, composition of the apical cytoplasm and presence of microvilli-like projections were discussed. Finally, our study describes in detail the internal ultrastructure of hollow hooks, evidencing the presence of cytoplasm, mitochondria and fibrils. The location of these fibrils may increase the area of contact surface of hooks on tentacles, possibly allowing for a higher tensile strength than that of solid hooks. We consider that gland location and shape, composition of tentacular wall layers, and hook internal structure may serve as useful characters for the taxonomy and phylogeny of Trypanorhyncha. RESEARCH HIGHLIGHTS: This is the first description of scolex internal ultrastructure in Grillotia carvajalregorum, showing the presence of glands arranged in two longitudinal acini at the pars vaginalis parenchyma, with potentially adhesive functions. The internal ultrastructure of serrate lanceolate spinitriches and acicular filitriches may reflect their specialization in attachment to the host intestinal mucosa and their involvement in nutrient absorption, respectively. Internally, hollow hooks have cytoplasm with mitochondria and fibrils, which are more widely distributed than in solid hooks, possibly increasing their tensile strength.

On the ultrastructure of the male reproductive tract in the Siberian hamster (Phodopus sungorus campbelli). I. The ductuli efferentes

Abstract: The efferent ducts of the Siberian hamster were studied using transmission electron microscopy. Structural evidence indicates the presence of three cell types. First, in the nonciliated cell, the apical cytoplasm was replete with coated vesicles and pits and several classes of tubular profiles. Dense fields of microvilli characterize the apices of these cells. Populations of dense bodies were present together with large nonmembrane-bound structures containing membrane fragments and amorphous, homogeneously electron-dense material. The significance of the latter 'juxtanuclear bodies' remains unresolved. Basally, elaborate plasma membrane interdigitations and intercellular canaliculi suggest the possibility of intercellular transport. Second, a cell was identified whose surface was replete with microvilli, among which were scant numbers of true cilia. Ciliogenesis was evident. Despite dense populations of microvilli, these cells exhibited none of tubular complexes characteristic of nonciliated cells. Third, there were cells whose surfaces exhibited dense populations of cilia and scant numbers of microvilli. Coated vesicles and apical tubular complexes were absent, but these cells contained multivesicular bodies, lysosomes and lipofuscin granules. Structural evidence points to three functionally different cell types in Siberian hamster efferent ducts.