Histological variations in myoepithelial cells and arrectores pilorum muscles among caudal, metatarsal and preorbital glands in Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884)

The morphological characteristics of myoepithelial cells and arrectores pilorum muscles were investigated in caudal, metatarsal and preorbital glands of Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884) using immunohistochemistry for alpha-smooth muscle actin. In the metatarsal, preorbital and general skin glands, myoepithelial cell layers continuously embraced the secretory epithelium, while in the caudal gland, discontinuous myoepithelial cell rows surrounded the apocrine tubules. There was a trend that the widths of the myoepithelial cells of the caudal and preorbital glands appeared to be thinner than those of the metatarsal and general skin glands. In the metatarsal gland, the arrectores pilorum muscles were highly developed and considerably larger than those in other skin glands.     

Microscopic Anatomy and Enzyme Histochemistry of the Canine Anal Canal

The microscopic anatomy of the anal canal was studied using routine histological methods and the light microscope in male and female dogs ranging from six months to 10 years of age. Precise anatomical boundaries were established for the zona columnaris , the zona intermedia , and the beginning of the zona cutanea. In an effort to clarify conflicting terminology concerning the anal canal, the term "anal sinus" ( sinus anales ) is applied to the shallow troughs located between the longitudinal mucosal ridges or columns (columnae anales) characteristic of the canine and human zona columnaris ; and the term "anal crypt" is used to represent and distinguish the terminal blind pockets of anal sinuses which extend into the lamina propria of the zona intermedia .
Anal glands were identified routinely in the z. columnaris and z. intermedia of the anal canal; dilated excretory ducts of the anal glands were frequently encountered, often filled with inflammatory cells. PAS-positive but Sudan Black-negative secretion was demonstrated in these ducts as well as within the secretory acini. Sebaceous, circumanal and apocrine sweat glands were restricted to the z. cutanea . Moderate to high alkaline phosphatase activity in the basement membrane of circumanal glands may suggest the presence of myoepithelial cells.     

The Process of Secretion in Swine Apocrine Sweat Glands

The secretory process in swine apocrine sweat glands were studied by electron microscope. The sweat appeared to result from three different mechanisms: (a) fluid transport, probably involving a region of complex cellular interdigitations adjacent to the basement membrane, (b) exocytosis of vesicles, which in this species seem to be derived from the Golgi apparatus and finally (c) apocrine secretion.     

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。     

Microscopic anatomy of the skin of the woodchuck (Marmota monax): comparison of woodchuck hepatitis virus-infected and non-infected animals.

Thirty-three woodchucks were used in this study. Seventeen animals were healthy adults, not infected with woodchuck hepatitis virus (WHV); 10 were healthy adults infected with WHV; 4 were noninfected neonates; 2 were infected neonates. Within the 4 groups of woodchucks, no histologic differences were detected on the basis of sex or age. Neither were histologic findings different between infected and noninfected woodchucks of similar ages. The average thickness of skin (as measured from the skin surface to the inner limit of the dermis) from the general haired body area was 2394 microns. The skin was thickest on dorsal body areas, and gradually became thinner on ventral body and medial limb areas. The epidermis consisted of 4 layers: stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. A stratum lucidum was present only in the epidermis of the footpads. There was no clear distinction between the superficial dermis and the deep dermis, except for the subtle differences in arrangement and size of collagen fibers. Elastic fibers were seen throughout the dermis, being more prominent in the superficial portion. Both compound and simple hair follicle arrangements were seen, with compound being more common. The arrectores pilorum muscles were largest in the skin over the dorsal body areas. Sebaceous glands were present either within the outer root sheath of hair follicles or in the dense connective tissue surrounding hair follicles. No apocrine sweat glands were found. However, there were abundant eccrine sweat glands in the subcutaneous fat of the footpads.     

Surface Ultrastructure of Ultimobranchial Epithelium in the Thyroid Gland of Donkey (Equus asinus)

Surface ultrastructural observation of the thyroid gland in donkey revealed the coexistence of certain unusual follicles or cysts, the ultimobranchial (UB) follicles, which exhibited large diameters and less regular outlines. In addition, several small follicles, cell nests or solid cellular masses were also demonstrated in association with these structures. Surface of most UB follicular cells was almost hexagonal in shape, studded with sparse or dense pleomorphic microvilli, which were much denser at the cellular borders. Each follicular cell bore single cilium that projecting over the cell surface. Interestingly, bleb-like apocrine protrusion of the apical cytoplasm of some follicular cells was frequently demonstrated. These apocrine blebs (or aposomes) were varied in shape, size and showed smooth or irregular surface. In addition to such aposomes, deep to shallow circumscribed or eroded areas of the apical cell surface was frequently demonstrated. These findings indicate that the UB follicular cells in donkeys, similar to those of camels, exhibit an apocrine activity alongside with the usual merocrine mode of secretion.     

The Poll Glands of the Dromedary (Camelus dromedarius): Ultrastructural Characteristics

The poll glands of the camel are tubuloalveolar glands. They consist of lobules separated by interlobular connective tissue. Adrenergic axons and blood vessels including fenestrated capillaries are present in the intralobular connective tissue in close proximity to the secretory cells. The prominent features of the secretory cell cytoplasm are many mitochondria, smooth endoplasmic reticulum, and many vesicles in various secretory stages.
It is concluded that the secretory cells have apocrine as well as merocrine modes of secretion. The glands may have the ability to uptake hormones and concentrate them. Additional work is needed before considering these glands as steroid-secreting glands.     

Morphology of the intermandibular gland of the Lesser mouse deer, Tragulus javanicus

The morphology of the intermandibular gland of the Lesser mouse deer (Tragulus javanicus), which plays an important function in marking area and territory and in the reproductive behaviour of the animal, was examined using immunohistochemistry, lectin histochemistry and scanning electron microscopy. The gland was composed of sebaceous and apocrine glandular material. Sebaceous glands occupied a greater area of the total gland and consisted of many large lobules with polyhedral cells having a pale cytoplasm. The sebaceous gland, being holocrine, possessed no special secretory ducts. The apocrine gland was lined by cuboid cells and the secretory products were often seen in the apical portions of the cells. Myoepithelial cells contained actin filaments lining the basal membranes of the apocrine gland and were surrounded by nerve fibres which immunostained with protein gene product 9.5. The secretion of the gland appears to be a mixture of larger amounts of lipid material from sebaceous glands, and glycoconjugates secreted by both sebaceous and apocrine glands. Lectin histochemistry detected these as galactose, N-acetyl-D-galactosamine, N-acetyl-D-glucosamine, D-mannose and D-glucose. The male gland was larger in size and contained more N-acetyl galactosamine and N-acetyl glucosamine in its secretion than the gland of the female. This implied the presence of sexual differences in secretions in the intermandibular gland of the Lesser mouse deer.     

Immunohistochemical study of 3 beta-hydroxysteroid dehydrogenase in dog's perianal sinus

In this study, the localization of 3 beta-hydroxysteroid dehydrogenase (3beta-HSD) activity in the wall of canine perianal sinus (PS) was determined. The 3 beta-HSD activity was found out both in the cytoplasm of cells, situated in the propria and forming clusters adjacently to apocrine glands and in the cytoplasm of some epithelial cells in apocrine cells' glands. The results obtained about the 3 beta-HSD activity allowed us to propose a role of this enzyme in PS development and possibly, in tumourogenesis.     

The "protective acid coat" of the skin of our domestic animals

The study reviews and discusses functional aspects of the so-called "acid mantle" of the integumentum commune of domesticated mammals and birds. The problems referred to are closely related to the skin surface-pH and different factors influencing this phenomenon (chemical composition of the skin surface film, secretory activity of apocrine tubular glands, structure of the microflora, lack of skin glands in birds). It becomes evident, that an "acid mantle" of the skin of domesticated animals cannot be verified, and that normal skin-pH (medium values weakly acid to alkaline) exerts no microbicidal effects. Integumental antimicrobial properties may rather be connected with free fatty acids as decomposition products of skin lipids.     

Microscopy of the echidna sublingual glands

The secretory units and duct system of the echidna sublingual glands exhibit subtle architectural modifications to accommodate the viscous secretion produced by these glands. The glands are compound tubular glands, the secretory units of which are elongate with open lumina and consist only of mucous cells. Closely packed spindle-shaped myoepithelial cells invest the secretory units, but are absent around the ducts. The branched secretory tubules open into an abbreviated duct system characterized by wide lumina. Striated ducts normally associated with the second portion of the intralobular duct system are absent. The duct system shows the most obvious modification of general salivary gland architecture presumably to accommodate the viscous secretion propelled from the secretory units by surrounding myoepithelial cells.     

Histomorphology of the Proventriculus of three Species of Australian Passerines: Lichmera indistincta, Zosterops lateralis and Poephila guttata

Histomorphology of the proventriculi of nectarivorous, granivorous and omnivorous passerines was studied. The proventriculus consisted of mucosal, submucosal, muscularis and serosal layers. Proventricular wall was thickest in omnivore, thinnest in granivore and intermediate in nectarivore. The openings of mucosal glands had a single spiral-like fold of mucosa in the omnivorous Silvereye, 2–3 spirals in the granivorous Zebra finch and 4–5 spirals in the nectarivorous Brown honeyeater. The mucosal glands were arranged in a uniform row in the wall of the organ and opened individually via a primary duct to the lumen of the proventriculus. The surface epithelial cells of the tunica mucosa contained secretory cells and the proventricular glands contained endocrine, neck and oxynticopeptic cells. The ultrastructural features of the oxynticopeptic cells changed from the oral to the aboral portion of the gland. In the oral region, the cytoplasm presented numerous, smaller (600–900 nm) homogenously dense zymogen secretory vesicles and larger (0.8–2.3 μm) pale floccular, tubular, mucin-like secretory granules, few small mitochondria and RER while in the aboral portion of the gland, the cytoplasm presented numerous, large mitochondria with closely packed cristae, secondary lysosome and infolding of the basal and apical cell membrane. The tunica sub mucosa was thin with occasional large blood vessels. The tunica muscularis consisted of inner longitudinal, middle circular and outer longitudinal layers. The external tunica serosa contained large bundles of myelinated and unmyelinated axons that were possibly branches of the intestinal nerve. The structural adaptations of the proventriculi of these three species to their various diets are discussed.     

Cytoarchitectural differences of myoepithelial cells among goat major salivary glands

Previously, the distribution of myoepithelial cells (mecs) in the salivary glands was studied by both immunohistochemistry, and transmission electron microscopy; however, little was elucidated concerning their morphological features, especially in goats. This study was performed to investigate the correlation between the cytoarchitecture of the mecs in goat major salivary glands (parotid, mandibular, and sublingual glands) and the nature of the saliva secretion. The cytoarchitectural features of the mecs were examined by scanning and transmission electron microscopy as well as immunohistochemically. The secretory endpieces in the parotid gland are of the pure serous type, but in both the mandibular and sublingual glands they are of the mixed type. In all studied glands, the intercalated ducts were covered by mecs which, unlike the large stellate cells that surrounded the secretory endpieces, were spindle-shaped with few cytoplasmic processes. Interestingly, the mecs were found to bulge on the basal surfaces of the serous acini and intercalated ducts in all glands and to be in close contact to the seromucous tubules surface in the mandibular and sublingual glands forming a continuous network around it. In conclusion, the differences in the degree of development of the mecs as well as the number of their cytoplasmic processes may be correlated with the nature of the secretion and the number of the secretory granules. Thus these observations may have some relevance in the diagnosis of atrophy and pathogenic conditions of these glands.     

Histochemical Analyses of Anti‐Microbial Substances in Canine Perianal Skin with Special Reference to Glandular Structures

Circumanal glands are prominent features of the canine perianal skin, which are often located near to the sebaceous glands and apocrine glands. As the functional relevance of circumanal glands is yet unknown, we studied the localisation of sialic acids and anti‐microbial substances (lysozyme, immunoglobulin A, lactoferrin, β‐defensin) in these glandular structures by lectin histochemistry and immunohistochemistry. The glands exhibited a number of sialic acids that were linked to α2‐6Gal/GalNAc and α2‐3Galβ1‐4GlcNAc. Additionally, lysozyme, lactoferrin and β‐defensin could be demonstrated in the three types of skin glands, whereas IgA was only detectable in the apocrine glands. The results of the study suggest the specific significance of the circumanal glands. Independent of a certain endocrine role, their products may mainly function as protective agents to preserve the integrity of the anal region, considering that sialic acids and anti‐microbial substances are important in defence mechanisms.     

Gross,Histological and Ultrastructural Features of the Bulbourethral Gland in the Greater Cane Rat (Thryonomys swinderianus)

The present study examines the structure and ultrastructure of the bulbourethral glands in 10 sexually matured male greater cane rats raised in captivity. Following anaesthesia, the rats were perfusion‐fixed transcardially and the bulbourethral glands dissected out. Upon morphologic and morphometric analysis, the Cowper's glands were observed to have an average volume of 0.24 ± 0.08 ml, a diameter of 6.3 ± 0.6 mm and weighs 0.199 ± 0.06 g. The paired, gourd‐shaped tubuloalveolar glands were surrounded by dense connective tissues and separated into lobules by capsular septae. Each lobule consists of endpiece/secretory units and excretory ducts lined by simple glandular epithelium and pseudo‐stratified epithelium, respectively. The round end pieces consisted of 8–10 pyramidal to columnar epithelial cells with flattened, basally located nuclei and granule‐filled cytoplasm that bounded a narrow glandular lumen. The striking ultrastructural features of these secretory cells were the presence of some granules with uniform electron density and those with regions of lesser density as well as the absence of secretory vacuoles. Another unique characteristic of these secretory granules is the presence of electron dense strands radiating from their surfaces. The apical surfaces of the cells were also studded with abundant microvilli. From the findings, the structure of bulbourethral glands in the greater cane rat shows more resemblances to that of humans than to its rodent phylogeny. These findings serve as additional knowledge in the structural interpretation of the bulbourethral gland and its secretory products.     

双峰驼指（趾）枕的解剖结构

观察了２０个双峰驼前后脚标本。结果表明：双峰驼前肢指枕较后肢趾枕发达。指（趾）枕由表皮、真皮和皮下组织构成。指（趾）枕表皮角化，内有许多漏斗状角质小管，真皮乳头伸入其中。第３、４指（趾）枕结合形成一角质盘。真皮内有大量汗腺，肉眼可见其呈淡黄色颗粒，直径约１ｍｍ。每个指（趾）有３个脂肪垫和１个弹性纤维垫。第３、４指（趾）枕的深筋膜形成指（趾）枕垫包囊，其轴侧壁在指（趾）间隙结合，构成指（趾）枕中隔。在指（趾）枕真皮与指（趾）枕垫包囊之间有一发达的指（趾）枕静脉网     

Surface Ultrastructure of Ultimobranchial Remnants in the Thyroid Gland of Buffalo (Bos bubalis)

The remnant of ultimobranchial (UB) body in the thyroid gland of adult buffalo was studied. This remnant appeared in the form of irregular and elongated follicles of various size and shape with folded lumen. These structures occupied a peripheral location beneath the capsule, as well as being embedded mostly in the vascular connective tissue of the thyroid. Calcitonin cells were predominantly localized in the UB follicles. Scanning electron microscopy revealed that surface of most UB follicular cells was almost flat and polyhedral or hexagonal in shape. Other follicles possessed cells with dome shaped apical surface demarcated by a shallow intercellular depression. The luminal surface of the follicular cell lining was studded with microvilli that appeared with various density and length and were numerous at the cellular borders. Interestingly, most of UB follicular cells were provided with single cilium, projecting over the cell surface. Notably some UB follicles presented various stages of apocrine activities.     

Perineuronal Nets in the Central Nervous System

The remnant of ultimobranchial (UB) body in the thyroid gland of adult buffalo was studied. This remnant appeared in the form of irregular and elongated follicles of various size and shape with folded lumen. These structures occupied a peripheral location beneath the capsule, as well as being embedded mostly in the vascular connective tissue of the thyroid. Calcitonin cells were predominantly localized in the UB follicles. Scanning electron microscopy revealed that surface of most UB follicular cells was almost flat and polyhedral or hexagonal in shape. Other follicles possessed cells with dome shaped apical surface demarcated by a shallow intercellular depression. The luminal surface of the follicular cell lining was studded with microvilli that appeared with various density and length and were numerous at the cellular borders. Interestingly, most of UB follicular cells were provided with single cilium, projecting over the cell surface. Notably some UB follicles presented various stages of apocrine activities.     

Sweat gland hamartoma resembling human syringocystadenoma papilliferum in two young cats

Syringocystadenoma papilliferum, a hamartoma with mostly sweat gland, but also follicular infundibular elements, is described on the flank and head of two young cats. Clinically, lesions were cutaneous plaques characterized by irregular but sharply demarcated borders and a roughened, hyperpigmented surface. Complete surgical excision in one case was curative. Histologically, the lesion was limited to the superficial dermis and consisted of coalescing units of proliferating sweat glands. The proliferation was tubular or papillary, and may have been epitrichial, opening within dilated hypertrophied follicular infundibuli, or atrichial. Three types of epithelium were observed, recapitulating the formation of the follicular-sweat gland unit with infundibular, ductal and secretory epithelia. The glands reacted positively for alpha cytokeratin 8 and were supported by fibrous tissue with a plasmacytic, lymphocytic and neutrophilic infiltrate. As in humans, this lesion may be classified within the hamartoma-nevus-type category.