Light and electron microscopical observations on the terminal airways and alveoli of the lung of the SA (Cape) fur seal Arctocephalus pusillus

During activities of the Sea Fisheries Research Institute at Kleinzee, lung samples from six South African fur seals were collected. The terminal airways showed pseudostratified ciliated columnar epithelium with numerous goblet cells and occasional brush cells. Smooth muscle, cartilage and submucosal glands were also present. The epithelium changed over a short distance, in the smaller airways, through pseudostratified columnar non-ciliated to simple cuboidal epithelium with no goblet cells. The columnar non-ciliated cells contained secretory granules, which appeared to be serous. No Clara cells were found. Cartilage and muscle were present throughout, up to the origin of the alveolar ducts, but the glands disappeared together with the goblet cells. Alveoli were lined by types one and two alveolar epithelial cells, with subepithelial capillaries. They were divided by an alveolar septum with a well developed alveolar knob. This knob contained elastic fibres and fibroblasts, but not the smooth muscle cells which are present in terrestrial mammals and in Phocidae.     

Histology,histochemistry and ultrastructure of the nasopharyngeal tonsil of the buffalo (Bubalus bubalis)

The light microscopic appearance and ultrastructure of the nasopharyngeal tonsil (tonsilla pharyngea), collected from 12 adult buffaloes of local mixed breed, were explored for the distribution of different types of epithelia, lymphoid tissue and high endothelial venules. The tonsillar mucosa was lined by pseudostratified columnar ciliated epithelium having goblet cells. The respiratory epithelium associated with the underlying lymphoid tissue formed the lymphoepithelium. The epithelium was further modified into follicle‐associated epithelium (FAE) characterized by reduced epithelial height, presence of a few dome‐shaped cuboidal cells equivalent of the M‐cells and absence of goblet and ciliated cells. The lymphoid tissue was distributed in the form of isolated lymphoid cells, diffuse lymphoid tissue and lymphoid follicles, mainly distributed within the propria‐submucosa along with the sero‐mucous glandular tissue. The goblet cells of the respiratory epithelium and the acinar cells contained different mucopolysaccharides. Scanning electron microscopy of the surface mucosa demonstrated a dense mat of cilia, island‐like arrangement of microvillus cells, M‐cells and a few brush‐like cells. The transmission electron microscopy revealed the different cell organelles of the respiratory epithelium and the FAE. Lymphocyte migration via the high endothelial venules in the propria‐submucosa was also observed.     

Histological Characteristics of the Tracheobronchial Tree of the Least Shrew (Cryptotis Parva)

The least shrew (Cryptotis parva) is a small vomit‐competent insectivorous species which has recently been introduced as an emesis animal model in the laboratory. In this study, the respiratory system of the least shrew was examined and compared with the well‐established larger species routinely used in the laboratory. Five least shrews (4–5 g body weight, 45–60 days old) were used. Standard histological procedures were followed for light microscopic examination. The lining epithelium of the trachea was found to be pseudostratified ciliated columnar (PSCC). Three types of cells were easily identified, basal and ciliated as well as few goblet cells interspersed among the ciliated cells and they were not clearly recognizable. A few tracheal seromucous glands were located at the free end of the C‐shaped cartilaginous rings. The cartilaginous rings are replaced by smooth muscle cells before the bronchi enter into the lung. The lining epithelium of tracheobronchial tree gradually changes into simple cuboidal epithelium that lacks goblet cells. However, the division of the tracheobronchial tree is similar to other mammalian species. On the other hand, the principal bronchus lacks cartilaginous plaques as it becomes intrapulmonary bronchus. The wall of the bronchi is supported by thick layers of spirally arranged smooth muscles. Two types of cells were readily recognizable: basal and ciliated cells, with rarely observed goblet cells. In addition, the PSCC epithelium changes into simple cuboidal much earlier in the bronchial division relative to other species.     

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.     

Oocyte Morphology from Primordial to Early Tertiary Follicles of Yak

The objective of this study was to investigate the developmental morphology of yak oocytes from the primordial follicle to the tertiary follicle. Yak oocytes from resting primordial (n = 6), activated primordial (n = 12), primary (n = 9), secondary (n = 7) and early tertiary (n = 5) follicles were processed and analysed by light and transmission electron microscopy. The resting primordial follicular oocyte was characterized by relatively smooth surface on the oolemma, the accumulation of free and organelle‐related smooth (SER) and rough endoplasmic reticulum (RER), round or oval mitochondria, and polyribosomes on the surface of the RER and throughout the ooplasm. The activated primordial follicular oocyte was dominated by numerous coated pits and coated vesicles on the oolemma, and round mitochondria. Up to the secondary follicular stage the oocyte displayed an increase in the number of microvilli, polyribosome, Golgi complexes and mitochondria with distinct cristae. During the secondary follicular stage, formation of the zona pellucida, development of a desmosome‐like connection between the oocyte and the granulosa cells, formation of the cortical granules in the oocyte and elongated mitochondria in nearly all oocytes were seen. In the early tertiary follicular oocyte, the perivitelline space was present and a decrease in free SER and RER in the ooplasm occurred; finally, the nucleus migrated from an eccentric to a peripheral location. In conclusion, the growth of the yak oocyte is associated with the relocation and modulation of a number of cytoplasmic organelles as well as the development of oocyte‐specific structures such as the zona pellucida, desmosome‐like connection and cortical granules.     

鹅胸腺APUD(样)细胞的超微结构

应用透射电镜在鹅胸腺内发现一种ＡＰＵＤ（样）细胞。这种细胞形态不规则,有突起伸入相邻细胞之间;胞核圆形,电子密度低,核仁明显;胞质内含有粗面内质网、线粒体等丰富的细胞器。其主要特征是含有大量的多分布于胞质一侧的膜包小分泌颗粒,呈圆形或椭圆形,大小不等,直径１１０～５５０ｎｍ,有些颗粒在界膜与内含物之间可见低电子密度的晕轮。根据其超微结构特征,可将颗粒分为３型：Ⅰ型颗粒为中等电子密度;Ⅱ型颗粒为均质状高电子密度;Ⅲ型颗粒在中等电子密度中含有一高电子密度的核芯。作者认为这种细胞属于内分泌细胞,并且很可能是分泌肽类激素的ＡＰＵＤ细胞。     

Ultrastructural features of the uterus in the sexually immature ostrich (Struthio camelus) during periods of ovarian inactivity and activity

The ultrastructure of the surface epithelium and tubular glands of the uterus in the immature ostrich is described. In ostriches with inactive ovaries the uterus is lined by a non-ciliated simple columnar epithelium, with basally located heterochromatic nuclei. Scanning electron microscopy revealed that these non-ciliated cells have a dense microvillous cover. A simple columnar to pseudostratified columnar epithelium, comprised of non-ciliated and ciliated cells, lines the uterus in birds with active ovaries. The ciliated cells possess a wide luminal region, which contains a nucleus and various organelles. An accumulation of secretory granules was observed in the apical regions of the non-ciliated cells, as well as in a few ciliated cells. In addition to non-ciliated and ciliated cells, a cell type with rarefied cytoplasm was also identified. These cells appear to correspond to calcium secreting cells identified in other avian species. The results of this study indicate that, although uterine differentiation is present in immature ostriches with active ovaries, the production of secretory product appears to occur mainly in non-ciliated epithelial cells.     

肺离子细胞相关蛋白ATP6V0D2在不同年龄牦牛肺内分布和表达

本研究旨在揭示肺离子细胞相关蛋白ATP6V0D2在不同年龄组牦牛肺中的分布和表达特点,探索ATP6V0D2在牦牛肺适应高原低氧环境中的结构形成和可能调控作用。利用免疫组织化学,qRT-PCR和Western blot对初生、幼年、成年和老年4个年龄组牦牛肺中ATP6V0D2的准确分布位置及相对表达量进行研究。结果显示,ATP6V0D2主要分布在肺内支气管及其分支的管壁上皮黏膜层的纤毛细胞和克拉拉细胞中;在成年组和老年组呈强阳性表达,ATP6V0D2在不同年龄组牦牛肺中均有不同程度的表达,以初生组表达量最高,与其他3组相比较,差异性显著（P<0.05）。在蛋白水平上,ATP6V0D2在成年组中的表达量显著高于其他3组（P<0.05）;初生组、幼年组、老年组两两相比较,差异性均显著（P<0.05）。ATP6V0D2在不同年龄牦牛肺细支气管上皮细胞中均有表达,但不同年龄组间的表达存在显著差异（P<0.05）。肺离子细胞相关蛋白ATP6V0D2表达量的不同与牦牛肺对低氧环境的适应性过程有关,纤毛细胞和克拉拉细胞与肺离子细胞的功能具有相关性,在牦牛肺适应高原低氧环境、防止气道损伤或修复过程方面发挥重要作用。     

Light and scanning electron microscopic studies of the nasal turbinates of the horse

The nasal turbinates of 5 young horses were studied by light and scanning electron-microscopy. Stratified cuboidal epithelium lined the rostral part of the dorsal and ventral nasal turbinates of the vestibular region. The polyangular microvillus cells of this region were separated by linear depressions. The mid and caudal parts of the dorsal and ventral nasal turbinates and the rostral part of the ethmoturbinates were lined by pseudostratified columnar ciliated respiratory epithelium. Numerous cilia with dilated blebs on the ciliated cells concealed adjacent non-ciliated supporting cells and goblet cells. The olfactory zone consisting of the olfactory vesicle and a dense network of olfactory cilia localized to the caudal part of the ethmoturbinates. The three regions were delineated from each other by transitional zones.     

Experimentally induced parainfluenza type 3 virus infection in young lambs: pathologic response

Pulmonary changes in five 1-week-old, colostrum-deprived lambs transtracheally inoculated with parainfluenza type 3 virus were studied by immunofluorescent, microscopic, and ultrastructural techniques. The lambs were killed at postinoculation days (PID) 3, 5, and 7. Immunofluorescence specific for parainfluenza type 3 virus was first seen in small airways and alveolar epithelium and later in the lumens of airways and alveoli and, to a lesser extent, in the interstitium of the lungs. Grossly, there were multifocal areas of consolidation in all lobes of the lungs. These areas were characterized microscopically by bronchiolitis and interstitial pneumonitis. The bronchiolitis involved the terminal airways and consisted of necrosis and sloughing of epithelial cells followed by hyperplasia of the epithelium. The interstitial lesion comprised extensive infiltration of alveolar septa and alveoli with macrophages and the necrosis of alveolar epithelium. This was followed by hyperplasia of the epithelium. Degenerated bronchiolar and alveolar epithelium contained numerous intracytoplasmic inclusions early in the infection, but such inclusions were not seen in the lambs killed at PID 7. The degenerated changes were also seen with the electron microscope, as were numerous inclusions of viral nucleoprotein and a few viral buds at PID 3 and 5. Viral inclusions and buds were seen in ciliated and nonciliated bronchial epithelial cells and type I and type II alveolar epithelial cells.     

Ultrastructural changes of the tracheal epithelium after vaccination of day-old chickens with the La Sota strain of Newcastle disease virus

The progression of tracheal lesions induced by vaccination of day-old specific pathogen-free chicks with the La Sota strain of Newcastle disease virus (NDV) was examined by relating surface changes as observed by scanning electron microscopy with subcellular changes seen by transmission electron microscopy. NDV infection resulted in hypertrophy of goblet cells, their rupture, and the formation of excess mucus. Activation of goblet cells peaked within 4 days postvaccination. Afterward, the activation levels gradually decreased. At the level of the ciliated cells, a marked increase in the proportion of nonciliated to ciliated cells and later an almost complete deciliation of the tracheal surface were observed because a simple squamous to cuboidal epithelium replaced the original pseudostratified epithelium. Fifteen days postvaccination, all epithelial damage was restored. Because the observed vaccination-induced lesions are detrimental to epithelial integrity and function as a barrier against invading microorganisms, they might explain at the ultrastructural level the secondary complications of vaccination with the La Sota strain against NDV.     

不同发育阶段高原牦牛肺泡超微结构的研究

利用透射电镜和计算机图像分析系统对1日龄、30日龄、180日龄和成年4个年龄组的高原牦牛肺泡超微结构进行观测,并与同日龄平原黄牛进行比较。结果表明:不同发育阶段高原牦牛和平原黄牛肺泡壁均由扁平的肺泡I型上皮细胞和立方的肺泡II型上皮细胞组成,气-血屏障均由肺泡I型上皮、基膜和肺泡隔毛细血管内皮3层结构组成,但高原牦牛肺泡I型上皮处可见一些凹陷和空泡状结构。此外,1日龄高原牦牛肺泡II型细胞明显多于同日龄黄牛;除1日龄外,其余年龄段高原牦牛的气-血屏障算术平均厚度和调和平均厚度均显著小于同日龄平原黄牛(P<0.05)。高原牦牛气-血屏障的算术平均厚度和调和平均厚度随年龄增加不断减小,这不同于平原黄牛随年龄增加不断增大的特点。结论:高原牦牛出生后肺泡迅速发育,在超微结构方面表现出较多适应高原低氧环境的组织学结构特点。     

Histology, immunohistochemistry and ultrastructure of the equine tubal tonsil

The tubal tonsil of the horse surrounds the pharyngeal opening of the eustachian tube and is lined by pseudostratified columnar ciliated epithelium interspersed with areas of follicle-associated epithelium (FAE) heavily infiltrated by lymphocytes but devoid of goblet and ciliated cells. Scanning and transmission electron microscopy revealed microvillous cells and cells with features characteristic of M cells such as reduced microvilli or depressed bare surface, more numerous mitochondria, small vesicles and lysosomes, as well as vimentin filaments and epitopes specific for GS 1-B4 as previously seen in the nasopharyngeal tonsil. M cells were also identified in areas of respiratory epithelium not associated with lymphoid follicles and appeared to be the nasal mucosal counterparts of recently described intestinal villous M cells in the mouse. The underlying lymphoid tissue of the FAE was generally organized as solitary lymphoid follicles without germinal centres in contrast to the diffuse and large amount of organized lymphoid follicles with germinal centres that characterize the nasopharyngeal tonsil. CD8+ T and B-lymphocytes were much fewer than in the nasopharyngeal tonsil. High endothelial venules were mainly oriented towards the parafollicular area and contained much fewer endothelial pores and vesiculo-vacuolar organelles. Finally, scattered small clusters of mucus acini and striated muscles were other features that differentiated the tubal and nasopharyngeal tonsils.     

Comparative histomorphological and ultrastructural study of the luminal epithelium of the isthmus in laying and moulting domestic fowls (Gallus domesticus)

This study describes ciliated, nonciliated and mitochondrial luminal epithelial cells of the isthmus in laying and moulting domestic fowls using histological and ultrastructural techniques. The ciliated cells were nonsecretory, while numerous electron‐dense secretory granules were present in the nonciliated cells of laying birds. Mitochondrial cells, occurring in two morphologically distinct forms, constituted the third type of epithelial cell present in the isthmus. The SEM study showed that the luminal epithelium was dominated by ciliated cells, the cilia of which partially obscured adjacent nonciliated cells. The involution of the luminal epithelium in moulting birds occurred via autophagy, apoptosis and necrosis. Autophagic inclusions, which included autophagosomes and autolysosomes, were present in the early degenerative phases of ciliated, nonciliated and mitochondrial cells. Nonciliated cells underwent degeneration via apoptosis, which was characterized by nuclear and cytoplasmic condensation. Apoptotic and necrotic ciliated cells were evident during the intermediate and advanced stages of regression. The presence of apoptotic cell death was confirmed using the TUNEL assay. Loss of cilia via the formation of cilia packets was observed using TEM and SEM. Necrotic cell death occurred in mitochondrial cells during the intermediate and late stages of degeneration. In conclusion, the findings of the study on isthmus involution in moulting birds suggest that autophagy is a process confined to the early stages of degeneration, while apoptosis and/or necrosis occur in the terminal stages of regression.     

Fine Structure and Peroxidase Activity of the Bovine Mandibular Gland Cells

The acini of the bovine mandibular gland consist of mucous and demilunar seromucous cells. The mucous cells contain electron-lucid mucigen droplets or mucoid masses, only rarely delimited by membranes. The cisternae of the RER communicate freely. Mitochondria are scarce. The seromucous demilunar cells contain considerably more granules, and perigranular membranes are far more common. Many granules have characteristic alternating electron opaque and less electron dense areas. The prominent RER appears to be associated with a peculiar labyrinth of interconnecting tubules. Mitochondria are numerous. Numerous myoepithelial cells are observed. The cuboidal cells of the intercalated ducts lack signs of secretory activity. The columnar cells of the striated ducts have extensive infoldings of the basal plasma membrane, associated with mitochondria. The cell apex contains many granulated vesicles. Endogenous lactoperoxidase activity could be demonstrated only in the demilunar cells, within the secretory granules, the RER, including the perinuclear cisternae, as well as the labyrinth mentioned above. A positive reaction could be observed over acinar lumina and in intercellular canaliculi. The possible role of peroxidase as a component of a bactericidal system of the bovine saliva is discussed.     

雌性中华鳖输卵管精子储存结构的研究

应用光镜和电镜技术,系统观察雌性中华鳖输卵管精子储存情况,显示与精子储存有关组织结构与细胞形态。结果表明,精子储存在雌性中华鳖输卵管的蛋白分泌部后部至子宫部,但各段的组织结构及精子储存量存在一定差别。蛋白分泌部后部上皮较发达,由典型的高柱状纤毛细胞和分泌细胞构成,固有膜中腺体多为泡状腺。上皮和腺体中含有大量高密度的膜性分泌颗粒,此段只有少量的精子储存。峡部较窄且固有膜内无腺体,上皮排列紧密并呈迷路样迂回分布,上皮细胞内高电子密度分泌颗粒成团集中分布在核上方。峡部管腔中分布着大量的精子,靠近管腔的精子或精子头部嵌入上皮纤毛之间或顶端凹陷的胞质中,且精子嵌入部分的细胞结构保持完整。子宫前部形成垂直于管腔的储精小管(SST),子宫上皮及此段SST上皮的分泌颗粒电子密度不均,含高密度电子致密斑,腺体中的分泌颗粒也呈现不同的内部结构。子宫部及SST的管腔中储存有大量精子。这些区段复杂的细胞结构及分泌活动,可能在精子储存中发挥重要作用。     

Ultrastructural studies on the pancreatic acini in duck (Anas boscas) and pigeon (Columba livia)

The aim of this research work was to study the histological structure of the pancreatic acini by transmission electron microscope in two avian species, duck and pigeon. The specimens were collected and processed for electron microscopic study. The results showed that the acini of the two avian species were two types; the first one was an electron dense and the second one an electron lucent. The light acinar cells were larger in size than the dark cells. These cells contained centrally located ovoid nuclei with prominent nucleoli and abundant euchromatin. The cytoplasm was electron lucent, with many rough endoplasmic reticulum, polymorphic mitochondria. Numerous zymogen granules were distributed in the basal part and around the nucleus, so these cells considered active cells. The dark acinar cells were characterized by an electron dense cytoplasm. The most prominent cell organelle in these cells were the zymogen granules that appeared in different sizes while other organelles as mitochondria, and rough endoplasmic reticulum were inconspicuous or few, so these cells were considered as inactive cells. The nucleus with indented nuclear membrane located centrally with prominent nucleoli and abundant heterochromatin. Prominent intercellular spaces between the individual acinar cells, as well as well-developed basement membrane separating the electron dense cells and the lumen contained the secretion between acinar cells. It could be concluded that the acinar cells in ducks and pigeons were divided into two types, that is, light and dark acinar cells which mainly attributed to the activity of these cells.     

Ultrastructural pathology of Bordetella avium infection in turkeys

One-day-old turkeys were infected intranasally with Bordetella avium, and tracheas were examined by scanning and transmission electron microscopy at 1 to 5 weeks post-inoculation (PI). The predominant ultrastructural lesions were progressive loss of ciliated epithelium with replacement by nonciliated cells, bacterial colonization of ciliated cells, membrane-bound crystalline inclusions in cytoplasma of epithelial cells, depletion of mucous granules, and distortion of tracheal rings and the mucosal surface. Tracheal surface exudates consisted of mucus, necrotic cells, heterophils, and fibrin. Ciliated cells were replaced by immature cuboidal cells characterized by abundant rough endoplasmic reticulum with small numbers of electron-dense mucous granules in the apical cytoplasm. Bacterial surfaces were rough and contained numerous pleomorphic, knob-like structures, 20-50 nm in diameter. Other changes included enlarged mucosal gland openings, cell extrusion marks, pleomorphic microvilli, and cells with small numbers of short cilia.     

Light and electron microscopic study of the thoracic respiratory air sacs of the fowl

There are conflicting reports in the existing literature on the nature of the epithelial lining and the content of the supporting connective tissue of the respiratory air sacs of birds. The present study describes the light and electron microscopic structure of the thoracic air sacs of the fowl. A simple squamous epithelium lined the greater part of the thoracic air sacs. The squamous cells characteristically contained vesicles filled with lamellar or myelinoid material. Localized areas of cuboidal to columnar ciliated epithelium were randomly distributed and often associated with underlying blood vessels. Isolated ciliated cells first appeared on squamous or low cuboidal cells and increased in frequency as the cells became taller. Occasional basal and goblet cells were seen between the ciliated columnar cells. A fibrous connective tissue stroma supported the epithelium. Fine elastic fibres were particularly prevalent immediately below the epithelium. Isolated smooth muscle myocytes were present in the connective tissue stroma. A sheet of smooth muscle extended some distance into the membrane from the attachment of the latter to the body wall. Numerous small blood vessels, lymphatics and occasional nerve bundles were observed in the stroma.