Sertoli Cell - Spermatid Tubulobulbar Complexes in the Ram

The fine structure of the tubulobulbar complex (TBC) of the ram seminiferous epithelium was studied in immersion-fixed testicular samples obtained in autumn (sheep's mating period). The TBC was visible during the last two stages of the seminiferous epithelium cycle. It originated as a tubular invagination of the Sertoli cytoplasm harbouring a complementary evagination from the spermatid head. Later, it expanded into a bulbous structure, finally becoming detached from the spermatid and apparently phagocytosed by the Sertoli cell. The significance of this transient structure is discussed and compared with previous reports for other eutherian mammals.     

Morphologic features of Sertoli cells in the intra-abdominal testes of cryptorchid dwarf goats

Light and electron microscopy revealed an age-related progression of alterations of Sertoli cells in the intra-abdominal and scrotal testes of unilaterally cryptorchid West African dwarf goats between the ages of 1 and 30 months. Alterations in the scrotal testis were, however, maturational and included differentiation of Sertoli-to-Sertoli cell junctional specializations, profusion of smooth endoplasmic reticulum, convolution of nuclear profiles, development of vacuolar components of the nucleolus, and an overall change in cell shape in response to proliferation of germinal cells. Corresponding features were observed in Sertoli cells of the contralateral intra-abdominal testis, but the cytoplasmic features were transient because the cells degenerated progressively. Early changes included segregation of the smooth endoplasmic reticulum into compact masses composed of dense, narrow cisternae, dilatation of the rough endoplasmic reticulum cisternae into large, irregular profiles, atrophy of the Golgi complex, and accumulation of lipid droplets and lipofuscin granules. Many of these organelles and inclusions no longer were obvious in Sertoli cells of 12- to 15-month-old goats; rather, intracellular vacuoles and dilated intercellular spaces had become common. In the 24- to 30-month-old goats, Sertoli cells in the intra-abdominal testis contained mostly microfilaments and basally located mitochondria with circular cristae in dense matrices. The Sertoli-to-Sertoli cell junctional specializations were structurally intact. These results indicated that, in spite of the unfavorable intra-abdominal environment, Sertoli cells of the intra-abdominal testis, before their degeneration, had developed features similar to those of the scrotal testis.     

Structural and ultrastructural characteristics of interrenal gland and chromaffin cell of matrinxã, Brycon cephalus Gunther 1869 (Teleostei-Characidae)

This work presents the structure and ultrastructure of the interrenal gland and chromaffin cells, as well as the morphology of the head kidney of Brycon cephalus. The head kidney is composed of fused bilateral lobes located anterior to the swim bladder and ventrolateral to the spinal column. The parenchyma revealed lympho-haematopoietic tissue, melano-macrophage centres, interrenal gland and chromaffin cells. The interrenal gland consisted of cords or strands of cells grouped around the posterior cardinal vein and their branches. Chromaffin cells are found in small groups, closely associated with the interrenal gland and/or under the endothelium of the posterior cardinal vein. So far, the ultrastructural analysis has revealed only one interrenal cell type which contained abundant smooth endoplasmic reticulum and numerous mitochondria with tubulo-vesicular cristae, characteristic of steroid-producing cells. Two types of chromaffin cells were observed. The first type was characterized by the presence of vesicles with round, strongly electron-dense granules, which were eccentrically located. Such cells were interpreted as noradrenaline cells. Meanwhile, cells which contained smaller vesicles and electron-lucent granules, with a small halo separating the granule from the vesicular limiting membrane, were identified as adrenaline cells.     

Primitive neuroectodermal neoplasia in coho salmon, Oncorhynchus kisutch

Twelve coho salmon, approximately 8 weeks old, were each observed to have a single neoplasm involving the dorsolateral axial skeletal musculature. The neoplasm was closely associated with the vertebrae in all cases. The neoplasm was composed of islands containing small cells with round and occasional spindeloid morphology. Neoplastic cells had basophilic cytoplasm and vesicular nuclei. These cells exhibited immuno-positivity only for vimentin and S-100 protein. Ultrastructurally, neoplastic cells had nuclei with a predominance of euchromatin, cytoplasm containing marked amounts of rough endoplasmic reticulum, scant amounts of smooth endoplasmic reticulum, and scattered mitochondria. Rudimentary cell junctions were occasionally observed between adjacent neoplastic cells. Based on the close association of these neoplasms with the vertebrae as well as the histologic, ultrastructural, and immunohistochemical findings, these neoplasms were considered to all be primitive neuroectodermal neoplasms.     

成鸡卵巢嗜酸性细胞、卵泡外腺细胞和卵泡膜腺细胞微细结构的研究

对成鸡卵巢的嗜酸性细胞、卵泡外腺细胞和卵泡膜腺细胞作H.E染色、油红—O染色和电子染色,然后进行光镜和电镜观察。结果:嗜酸性细胞单个分布在卵巢基质中,形态不一。胞核形态多样,异染色质数量中等,核仁位于核的偏中心部位。胞质中有许多电子密度较高的圆形嗜酸性颗粒,高尔基复合体发育良好,粗面内质网数量中等,有少量嵴少、基质电子密度低的线粒体,其它细胞器较少,油红—O染色阴性。卵泡外腺细胞分布在卵泡之间,由数个细胞结合成一细胞团。细胞形态多样。胞核圆形或卵圆形,一至数个核仁,异染色质少。胞质中充满大小不一的卵圆形脂滴,线粒体嵴多、基质电子密度较高,有管状嵴和板状嵴,还有较多囊泡状的滑面内质网,粗面内质网数量少,油红—O染色阳性反应。卵泡膜腺细胞也是数个细胞结合成一细胞团,分布在卵泡膜内层,结构与卵泡外腺细胞极为相似,油红—O染色阳性。卵泡外腺细胞和卵泡膜腺细胞都具有分泌类固醇激素细胞的结构特征。     

The Sertoli cell of the water buffalo--an electron microscopic study.

The ultrastructure of Sertoli cells in the seminiferous tubules of water buffaloes before and during sexual maturity was studied by transmission electron microscopy, with emphasis on the intranucleolar vesicular elements. Sertoli cells of animals under 12 months of age were distinguished from the germ cells by the presence of electron dense membrane bound bodies within their cytoplasm. These cells, referred to as basal indifferent supporting cells, were probably involved in the phagocytosis and elimination of degenerating spermatocytes, which failed to differentiate into spermatids and spermatozoa in animals under one year of age. In 12 month old animals, a few Sertoli cells exhibiting the vesicular elements appeared in the nucleolar region while in animals over 15 months of age Sertoli cells could be positively identified by the characteristic cytoplasm containing microtubules, elongated and electron dense mitochondria, extensive granular endoplasmic reticulum and the presence of spermatids in various stages of spermiogenesis. The vesicular elements in the nucleolar region of the Sertoli cells were most prominent at this stage. Ultrastructural features of the Sertoli cells revealed an abundance of ribosome-like particles surrounding the vesicles of varying size. Some of these vesicular elements contained amorphous material suggesting that they represent the products sequestered in the nuclear region for transport to the cytoplasm and that the process of spermiogenesis may be dependent on the ability of Sertoli cells to generate these products at sexual maturity.     

Submicroscopic changes in the luminal cells of the endometrium in cows during the estrus cycle

The structure of luminal epithelium cells in the endometrium of a cow shows little variation during the sexual cycle. Various coarse and irregular microvilli are produced on the surface of cells in pro-oestrus and oestrus. Starting from pro-oestrus, the relative volume of mitochondria increases to culminate in met-oestrus and di-oestrus. Their highest number was observed in oestrus; in met-oestrus they enlarge and many of them gradually disintegrate during di-oestrus. The maximum development of granular endoplasmic reticulum was observed in oestrus. The quantitative proportion of smooth membranes is small and their volume and surface area increase from the lowest values in di-oestrus up to culmination in oestrus. The highest number of lysosomes was observed at the end of sexual cycle and in pro-oestrus. In oestrus and met-oestrus the apical parts of cytoplasm contain many smooth-walled vesicles and cisterns.     

Fine structure of the retinal pigment epithelium, Bruch's membrane and choriocapillaris in the camel

The morphology of the retinal pigment epithelium (RPE) and closely associated Bruch's membrane and choriocapillaris was investigated by light and transmission electron microscopy in the camel (Camelus dromedarius). The study showed that RPE is composed of a single layer of hexanocuboidal cells that were joined laterally by a series of apically located tight junctions. In addition, adjacent from internal side of cell membrane at the level of tight junctions, an undefined structure which resembled the myofibrillar organization of skeletal muscles in appearance was located. These cells displayed numerous short basal infoldings and abundant thin apical processes which enclosed the rod outer segments. The epithelial cell nuclei were large, vesicular and eccentrically located. Within the epithelial cells, smooth endoplasmic reticulum was very abundant, while rough endoplasmic reticulum was present only in small amounts. Polysomes were also numerous and the mitochondria often displayed a ring-shaped structure. Lipofuscin granules were plentiful in all locations. Bruch's membrane (complexus basalis) was typically pentalaminate throughout the retina. The endothelium of the choriocapillaris facing Bruch's membrane was extremely thin and heavily fenestrated. These fenestrations displayed typical single-layered diaphragm as noted in most species.     

鸡轮状病毒感染的病理形态学观察

为确定鸡轮状病毒感染的病理变化特点，对自然发病和人工发病轮状病毒感染鸡进行了病理学研究。结果表明，该病特征性的病理剖检变化为肠黏膜脱落出血，呈卡他性炎症表现。特征性组织学变化为小肠绒毛显著缩短，肠腺深度增加；除肠绒毛缩短外，肠上皮还变为扁平或立方形，并伴发坏死、脱落，黏膜充血、水肿与淋巴细胞浸润。电镜观察，肠黏膜上皮细胞的线粒体肿胀，嵴变粗，排列紊乱；粗面内质网及滑面内质网均扩张呈圆形，粗面内质网表面的核糖体部分脱落，胞浆内游离的核糖体减少。     

Light and electron microscopic study of the livers of pregnant mice infected with Listeria monocytogenes.

Listeria monocytogenes cells were observed in the hepatic cell cytoplasm or in the phagosome at 24 and 48 hours but not at 72 hours after inoculation in pregnant mice. The presence of bacteria initially in a membrane-bound vesicle indicates that the bacteria enter the hepatic cells by endocytosis, resulting in eventual destruction of hepatic cells. Characteristic lesions of the liver at 24 and 48 hours after inoculation consist of multiple focal areas of necrosis. The initial neutrophilic reaction seems to give way to a mononuclear reaction (listeriomas) at 72 hours after inoculation. Dilation of rough endoplasmic reticulum and release of many of the bound ribosomes with a relative increase in the number of free ribosomes was observed. Hepatic lesions were not observed in control (nonpregnant) mice.     

Ultrastructural and ultracytochemical cyclic changes in the bovine uterine tube (oviduct) epithelium.

Ultrastructural and ultracytochemical features of the uterine tube (oviduct) infundibulum were studied in 8 Hereford cows, which were slaughtered in pairs on days 1 (estrus), 3, 9 or 10, and 18 of the estrous cycle. Fibrous granules (60 to 80 nm), which are supposedly related to basal body replication, were observed in the apical cytoplasm of ciliated cells. Close association between basal bodies and fibrous granules was apparent, especially during the follicular phase. Cilia were observed throughout of estrous cycle, although degeneration of cilia was not observed at any phase of the cycle. Prominent, striated rootlets were observed during both the follicular and luteal phases of the cycle. Maximum secretory cell differentiation was apparent during the follicular phase, at which time these cells were characterized by having a well-developed, rough endoplasmic reticulum with dilated cisternae, numerous ribosomes, and secretory granules of varied size and density. A prominent feature of the secretory granules was their membranous structure, consisting of concentric lamellae of equal dimensions. During the luteal phase, cytoplasmic protrusions were prominent, and extruded nuclei along with other cytoplasmic organelles were present in the tubal lumen. The presence of a well-developed, rough endoplasmic reticulum and numerous secretory granules during the follicular phase indicates that secretory activity of the uterine tube infundibulum may be stimulated by estrogen. During estrus, the cytoplasm of the stromal cells displayed abundant, rough endoplasmic reticulum with dilated cisternae. The increased and extensively dilated rough endoplasmic reticulum at the time of estrus probably indicates increased protein synthesis by the stromal cells. The presence of adenosine triphosphatase activity on the membrane of cilia suggests that this enzyme is involved in energy-forming reactions related to the vigorous action of cilia. The presence of acid phosphatase activity on the cell membrane of the epithelium, microvilli, and secretory granules may indicate involvement in the secretory mechanism of the cell.     

Ultrastructure of the thyroid gland of the one-humped camel (Camelus dromedarius)

Follicular epithelium of the thyroid gland of the one-humped camel was examined by light and electron microscopy. It consisted of a single type of epithelial cell which varied from flattened to columnar in shape. Follicular epithelial cells were characterized by the presence of markedly dilated cisternae of rough-surfaced endoplasmic reticulum, well developed Golgi apparatus, abundant small vesicles (150 nm to 200 nm in diameter) in the apical cytoplasm, and electron-dense colloid droplets measuring from 250 nm to 1600 nm. Follicular epithelial cells frequently showed apocrine secretion into colloidal lumens. Apocrine protrusions with smooth surface were dome-like or balloon-like structures and contained a fine granular matrix. These findings indicate that the morphological features of the follicular epithelial cells of the thyroid gland of the camel are essentially similar to those of mammals except for the presence of apocrine secretion, which is unique to the camel.     

Light and electron microscope studies on the nasopharynx and nasopharyngeal tonsil of the horse

Light and electron microscope studies were conducted on the nasopharynx and the nasopharyngeal tonsil of 15 young horses. The nasopharynx and nasopharyngeal tonsil was lined with pseudostratified columnar ciliated epithelium and goblet cells. The lymphoepithelium of the nasopharyngeal tonsil was folded forming crypts, the mucosa of which was modified into follicle associated epithelium characterized by stratified cuboidal epithelium, loss of cilia, absence of goblet cells and infiltration of lymphocytes. The lamina propria mucosae of the nasopharyngeal tonsil contained well-developed lymphoid tissue and clusters of seromucus acini. Scanning electron-microscopy revealed a dense mat of cilia covering the nasopharynx and nasopharyngeal tonsil. The follicle-associated epithelium consisted of different populations of microvillus cells in addition to M cells with very short microvilli and a few squamous and intermediate cells. Microvillus cells in the deeper part of the FAE had larger microvilli and their cytoplasm contained a dense population of mitochondria, smooth and rough endoplasmic reticulum, Golgi complexes and lysosomes. The flat surfaced M cell had a more electron-dense cytoplasm and contained small supranuclear vacuoles in addition to the organelles seen in microvillus cells.     

绒山羊原始生殖细胞继代培养研究

本研究对原代培养至6d时的鸟巢状绒山羊类胚胎干细胞(ES细胞)集落进行了传代培养。其结果:这些集落的细胞经6代克隆传代具有胚胎干细胞的诸多特征。细胞集落有典型的鸟巢状结构,AKP染色阳性,核型分析结果染色体正常。在透射电镜下细胞体积小,核大,有多个核仁而且核仁明显,细胞形态不规则,无明显界限。细胞质中核糖体较多,内质网、线粒体发达,部分细胞的核膜上出现小泡、染色质边集而形成凋亡小体。上述结果表明该细胞具有多能性,类似ES细胞。     

An Ultrastructural Study of the Sertoli Cell in the Water Buffalo (Bubalus bubalis)

The ultrastructure of Sertoli cell in the water buffalo (Bubalus bubalis) was observed in a transmission electron microscope. The nucleus had homogeneous nucleoplasm, scarce heterochromatin and multivesicular nuclear body (MNB). The MNB was composed of numerous vesicles and ribosome-like dense structures. The vesicles varied in size and number and contained a sparse and flocculent substance. In the indentation of the nucleus, aggregates of ribosomes were frequently observed. In the apical and middle region of the cell, long mitochondria and microtubules were distributed parallel to the long axis of the cell. Non-laminated smooth ER and some ribosomes were also recognizable throughout this region. In the basal region, widely-distributed laminated smooth ER was characteristic. Microfilament bundles at ectoplasmic specialization were irregularly arranged. Frequently-emerged nodular processes occasionally separated from basal lamina and formed round structures within Sertoli cytoplasm. Although these characteristics of buffalo Sertoli cell were very similar to those of the bovine studied, the aggregate of ribosomes was more developed in the buffalo.     

Fine structure of the retinal pigment epithelium, Bruch's membrane and choriocapillaris in the horse

The fine structure of the retinal pigment epithelium (RPE), Bruch's membrane and choriocapillaris was investigated by light and transmission electron microscopy in both the tapetal and non-tapetal fundus of the horse eye. In all locations, the RPE consisted of a single layer of low cuboidal cells. The epithelial cells were joined laterally by apically located tight junctions. These cells displayed numerous basal infoldings and abundant thin apical processes which enclosed the rod outer segments. The epithelial cell nuclei were large and located basally. Within the epithelial cells, smooth endoplasmic reticulum was very abundant, while rough endoplasmic reticulum was scarce, polysomes and mitochondria, which often display a ring-shaped structure, were abundant. Melanosomes were abundant in the non-tapetal area but absent in the tapetal area. Bruch's membrane was pentalaminate throughout the retina. The endothelium of the choriocapillaris was heavily fenestrated.     

Ultrastructure of schizonts and merozoites of Sarcocystis neurona

The ultrastructure of Sarcocystis neurona schizonts and merozoites was studied in specimens derived from cell culture and from the brains of infected mice. Schizonts and merozoites were located in the host cell cytoplasm without a parasitophorous vacuole at any stage of development. Merozoites divided by endopolygeny. Fully formed merozoites had a pellicle, numerous polysomes and ribosomes, smooth and rough endoplasmic reticulum, 22 subpellicular microtubules, 9-16 dense granules, 25-75 micronemes, a plastid, a Golgi complex, 1-3 mitochondria, a conoid, 2 apical rings, 2 polar rings, 0-6 lipid bodies, a nucleus and nucleolus, but no rhoptries. Most micronemes were located anterior to the nucleus including 1-6 micronemes in the conoid. Merozoites were either slender (7.3 microm x 1.7 microm) or stumpy (7.7 microm x 3.1 microm). Dense granules appeared to arise from the maturation face of the Golgi complex. The ultrastructure of in vitro derived schizonts and merozoites were similar to in vivo derived organisms.     

Distribution of actin filaments in the seminiferous epithelium of the Habu,Trimeresurus flavoviridis

The distribution of actin filaments was examined in the seminiferous epithelium of the Habu (Trimeresurus flavoviridis; snake), by transmission electron microscopy and fluorescence histochemistry. By transmission electron microscopy, actin filaments were clearly found only at the site between Sertoli cell and spermatid without a lattice‐like structure. Fluorescence histochemistry showed a weak labelling of actin filaments in the seminiferous epithelium, whereas these findings seem to be common among reptiles, they are different from those in mammals. Additionally, the bundles of actin filaments adjacent to the plasma membrane of Sertoli cells, appeared in other reptiles, were not observed in the Habu.     

日本七鳃鳗血细胞显微及亚显微结构

用光镜和透射电镜技术对１０尾日本七鳃鳗的血细胞进行了观察。结果表明：红细胞为圆形或椭圆形,胞质不很均匀,电子密度较低,含有板状嵴线粒体,核呈圆形或椭圆形。中性粒细胞表面有伪足,形态各异,胞质内含有Ａ、Ｂ２种颗粒（Ａ型颗粒为圆形,电子密度较低;Ｂ型颗粒为长椭圆形,电子密度较高）。嗜酸粒细胞数量较少,胞质内含有Ａ、Ｂ、Ｃ３种形态各异的有膜颗粒（Ａ型颗粒为圆形,电子密度较高,均质;Ｂ型为长椭圆形,颗粒中央有电子密度较高的长椭圆形致密芯;Ｃ型内含有电子密度较高的杆状致密芯,位于颗粒一侧）。单核细胞表面有伪足,胞质内含有粗面内质网、板状嵴线粒体、溶酶体和液泡。淋巴细胞为圆形,核较大,胞质内含有板状嵴线粒体、粗面内质网和嗜天青颗粒。血栓细胞体积较小,形态各异,胞质内含有线粒体、粗面内质网和细小颗粒。     

Ultrastructure of a feline extraskeletal giant cell tumor (malignant fibrous histiocytoma)

A subcutaneous extraskeletal giant cell tumor (malignant fibrous histiocytoma) was excised repeatedly from a 9-year-old Domestic Shorthair cat. Ultrastructurally, the mass was composed of fibroblast-like, histiocyte-like, and multinucleated giant cells, and some undifferentiated cells and mononuclear cells intermediate between the fibroblast-like and histiocyte-like cells. Fibroblast-like cells were characterized by abundant well-developed rough endoplasmic reticulum, relatively smooth cytoplasmic membranes, few lysosomal structures, and finely granular chromatin. Histiocyte-like cells resembled immature macrophages. The cell membranes had many villous projections. Rough endoplasmic reticulum varied in quantity. Lysosomes were numerous. Multinucleated giant cells had characteristics of both the fibroblast-like and histiocyte-like cells. No viral particles were seen.