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, ß-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 α2-3Galß1-4GlcNAc. Additionally, lysozyme, lactoferrin and ß-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.

[Contradictions in modern data on the structure and function of dog hepatoid circumanal glands]. / Protivorechiia sovremennykh dannykh otnositel'no stroeniia i funktsii gepatoidnykh tsirkumanal'nykh zhelez sobaki.

Since the 1950s, an erroneous viewpoint has gained a foothold in the special and reference literature that dog hepatoid circumanal glands have an abortive nature, lack efferent ducts, and show no signs of secretory activity. Nevertheless, most modern researchers indicate that these glands are actively functioning structures differentiated to exercise some function according to their histological pattern; however, no one has managed to define this function. The latest international publication (Atoji et al., 1998) considers dog circumanal hepatoid glands as a "circumanal body" similar to epidermis rather than glands. We discuss strong and weak points of the data on dogs hepatoid circumanal glands published in 1950s-1990s in comparison with those obtained in our purposeful long-term investigation of various hepatoid glands. We strongly disagree with the viewpoint of Atoji et al. (1998); hepatoid circumanal glands of dog and other canids should be considered as odor glands, their abundant protein secretion covers the skin surface in the circumanal region, it is preserved on fecal marks, and its smell is perceived during mutual nosing of the anal region.

[Detection of hepatoid glands and distinctive features of hepatoid acinus]. / Obnaruzhenie gepatoidnykh zhelez i otlichitel'nye cherty gepatoidnogo atsinusa.

In the 1920s-1930s, skin glands of a new type, hepatoid glands, were described in 13 mammal species (Rodentia, Canidae, and Bovidae). The hepatoid glands resemble sebaceous glands in their morphology, bur radically differ from them in specific structure of the acinus and another type of secretion. Later, these data either could not be confirmed or were considered insignificant and the hepatoid glands were described as modified sebaceous glands, glands with uncertain function, or modifications of epidermis. Based on the studies of various hepatoid glands in 22 species of Carniviora and Artiodactyla, the authors described in detail the characteristic features of the hepatoid acinus, which allow a precise discrimination of hepatoid and sebaceous glands. Extracellular secretory canaliculi have been described in the hepatoid glands, as well as the richness of hepatoid glands in protein, distribution of hydrophobic lipids in certain hepatoid glands, and formation of excretory ducts and cysts. The hepatoid glands are a source of great amounts of protein secreted in the merocrine way; the secretory substance of some of these glands has a strong odor.

Circumanal glands of the dog: a new classification and cell degeneration.

BACKGROUND: The circumanal glands of the dog are thought to be a glandular tissue, but there is some controversy as to whether they should be classified as exocrine or endocrine. In this study, we examined the nature of the circumanal glands to determine whether they should be described as exocrine, endocrine, or something else altogether. In addition, we investigated the cell degeneration in lobules of the circumanal glands in relation to the apocrine glands. METHODS: Light microscopic observations were made of paraffin sections stained with hematoxylin and eosin, and after immunohistochemical staining with antibodies against alpha-smooth muscle actin, keratin, filaggrin, and 3beta-hydroxysteroid dehydrogenase/isomerase (3beta-HSD). Samples were also examined by electron microscopy after fixation by aldehyde perfusion. RESULTS: The lobules of circumanal glands could be divided into two types on the basis of the presence or absence of cysts. Four layers (I-IV) were detected in the lobules with cysts. The outermost layer (layer I or the basal layer) consisted of flattened cells that contained bundles of tonofilaments and were stained immunohistochemically with the antibody against keratin. Layer II (the polyhedral or "spinous" layer) consisted of polyhedral cells that contained bundles of tonofilaments. These cells were connected to adjacent cells by desmosomes, interdigitations, and gap junctions, and they were immunopositive for keratin. A small number of polyhedral cells were immunopositive for 3beta-HSD. Layer III (the granular layer) was composed of flattened cells that contained hematoxylin-stainable granules and were moderately immunopositive for filaggrin. The innermost layer (layer IV or the horny layer) consisted of keratin. Lobules without cysts consisted only of layer I (the basal layer) and layer II (the polyhedral layer). Lobules of the circumanal glands were not directly connected to apocrine glands. Polyhedral cells degenerated and were phagocytosed by basal cells at a periphery of lobules. Then, basal cells phagocytosing degenerated polyhedral cells escaped from lobules, moved into the walls of apocrine glands, and, finally, dropped into the lumen of apocrine glands. CONCLUSIONS: Lobules of the circumanal glands have many characteristics of epidermis (a basal layer, a polyhedral or "spinous layer," a granular layer, and a horny layer) and they should not be classified as glandular tissue. The cysts in lobules can be interpreted as "closed hair canals." We suggest that steroid metabolism might occur in the polyhedral cells of the lobules.

[The caudal gland in the cat is a hepatoid gland]. / Khvostovaia zheleza koshki--gepatoidnaia.

The cat supracaudal gland is usually considered as a conglomeration of massive sebaceous glands, although the author of the only detailed description of its structure stated that it is a hepatoid gland (HG) of lower order. Investigation of the supracaudal gland in adult cats of both sexes showed that it is a massive layer of HGs opening either into dilated follicles of coarse hairs or into large cisterns. These glands possess all features specific for HGs: polyhedral cells, a network of intracellular canaliculi, abundant cytoplasmic protein granules, release of protein structures from the cells to adjacent canaliculi. The reasons for misinterpreting certain structural properties are discussed. It was shown that the cat caudal gland is a typical "embryonal" HG previously described in dogs and certain hollow-horned ruminants. They secrete protein and hydrophobic lipids, have wide excretory ducts, are connected with coarse hairs, are devoid of cysts, and have no sexual dimorphism. Formation of cisterns, special secretion receptacles of the cat supracaudal gland, was monitored. It begins with stagnation of the lipid-protein secretion in the hair follicle and progresses until transformation of the whole glandular lobe to the cistern and dissolving of the hair shaft in it.

[The sex dimorphism of the hepatoid circumanal glands in the dog and the dynamics of its development]. / Polovoi dimorfizm gepatoidnykh tsirkumanal'nykh zhelez sobaki i dinamika ego razvitiia.

The histology of sexual dimorphism of the dog hepatoid circumanal glands has not been studied before. Studies of hepatoid and other skin glands of the circumanal region of adult dogs and puppies (1 and 38 days) of both sexes have shown striking differences in the structure of this region in adult males and females and complete qualitative similarity in puppies of the both sexes. The hepatoid glands of adult males form a massive glandular layer comprising 91% of the skin thickness and supplanting all other glandular types. In adult females these glands are reduced to widely spaced islets (12% of the skin thickness), and the apocrine glands are the prevailing glandular type (53%). The hepatoid glands of puppies of the both sexes develop according to the same structural scheme, approaching rapidly to the glands of adult males. In female puppies they develop more rapidly, and at the age of 38 days their absolute size (length of glandular lobes) is already thrice that of adult females. The hepatoid glands of adult females undergo a very significant regress and possess several structural features suggesting their degeneration.

[New data on histological variants of hepatoid cells: the succession of histological variants in the histogenesis of the circumanal glands in the dog]. / Novye dannye o gistologicheskikh variantakh gepatoidnykh zhelez: smena gistologicheskikh variantov v gistogeneze tsirkumanal'nykh zhelez sobaki.

Studies on the circumanal skin of a three-week-old puppy have shown that, contrary to the adult dogs, sebaceous glands are absent here (although they are well-developed in other skin sites of the puppy). Hepatoid glands accompany every hair follicle; they differ considerably from hepatoid glands of adult dogs. Hepatoid circumanal glands of the three-week old puppy are represented by two histological varieties of this glandular type which are capable of producing hydrophobic lipids, are rather poor in protein, and do not possess cysts--while in adult dogs they are represented by only one variety incapable of synthesizing lipids, extremely rich in protein, possessing numerous cysts. Discussion concerns histogenesis, distribution, and function of certain hepatoid gland varieties which were first described by the authors in their previous publication.

[Histological variants of the hepatoid glands in representative Canidae and Cavicornia: the structural and histochemical characteristics]. / Gistologicheskie varianty gepatoidnykh zhelez u predstavitelei volch'ikh i polorogikh: strukturnye i gistokhimicheskie kharakteristiki.

Both the original material and the data from literature collected in two previous papers, show a considerable diversity of structure and secretion of the glands which constitute the hepatoid gland type. According to the body of available histological (including morphometrical) and histochemical data, the authors distinguish: a) features characteristic of the hepatoid gland type only which do not appear in other types of skin glands; b) seven histological varieties within the hepatoid gland type. These seven varieties can be united, according to the laws of their structure and function, into two groups (1-3 and 5-7), with an intermediate variety (4) between them. The first group includes hepatoid glands of the "classical" structure which has been previously detaily exampled by circumanal glands of the dog: these glands possess cysts, produce a purely protein secretion; the secretion type is merocrine. The second group comprises mero-holocrine hepatoid glands which are characterized by the absence of cysts, broader excretion ducts, and a capability to produce, besides protein, considerable amounts of melanin and/or hydrophobic lipids.

[The histological and histochemical characteristics of the hepatoid circumanal glands in the dog: the features of similarity and difference with the skin glands of other types]. / Gistologicheskie i gistokhimicheskie kharakteristiki gepatoidnykh tsirkumanal'nykh zhelez sobaki: cherty skhodstva i razlichiia s kozhnymi zhelezami drugikh tipov.

Three types of skin glands, the derivatives of the outer root sheath of the hair follicle, have been compared, which are represented by hepatoid, sebaceous and apocrine sweat glands. There are three characteristic properties inherent to hepatoid glands, existence of a network of intercellular secretory tubules, lysis of some secretory cells during the duct formation which is not the fatty transformation and cyst formation.

Macroscopic and histologic study to differentiate large glands and bulbi in the perianal body region of the male gray short-tailed opossum, Monodelphis domestica.

On either side of the cloaca of the male Monodelphis domestica, there is a large pack of globular structures lying between the external skin and the ischial arch. The structures within each of these bilateral complexes can be classified into three groups. Group 1 comprises different kinds of glands. There are two large glands, "Paraproctic glands" according to Schaffer (1940), whose spacious cavity is bounded by a secretory epithelium. The secretion is holocrine in a way that cells are shed into the wide cavity. Further, there are two large bodies built of sebaceous acini around a central cavity. The inner surface of the cavity is a squamous stratified epithelium. A peripheral layer of secretory tubuli completes the structure's wall. The bodies are referred to as "Circumanal glands" according to Schaffer (1940). Their excretory ducts end into the cloaca. Group 2 is located between the glands of group 1 and group 3. Macroscopically, the structures of this group are easily mistaken as glands, however, histologically they are identified as a bilateral bulb of the corpus spongiosum, and as a bilateral bulb of the crus of the corpus cavernosum penis. Group 3 includes three different glands that end into a bilateral expansion of the urethra. These accessory genital glands are very distinct due to the histologic characteristics of their secretory epithelium.

Aspectos anatômicos e histológicos das glândulas peri-anais da cuíca Philander opossum Linnaeus, 1758 / Anatomic and histological aspects of the perianal glands of the four-eyed Philander opossum Linnaeus, 1758

Foram estudados os aspectos morfológicos das glândulas perianais da cuíca Philander opossum: Estes marsupiais apresentam dois pares de glândulas perianais situadas respectivamente à direita e à esquerda do ânus. Cada par está formado por uma glândula lateral e outra medial. Estas glândulas estäo alojadas na fossa ísquio-retal, sob a pele da regiäo perianal, sendo a glândula medial de coloraçäo perolácea e menor que a glândula lateral, que é de coloraçäo ocre. Cada uma destas glândulas está formada pela associaçäo de vários lóbulos interligados e envolvidos pela mesma cápsula fibro-muscular. Os ductos menores da glândula medial se reúnem formando um ducto principal único antes destes emergir na superfície da glândula. Os ductos menores da glândula lateral emergem separados na sua superfície, indo se reunir mais à frente, formando o ducto principal desta glândula. Os ductos principais de ambas as glândulas correm paralelos até próximo ao ânus, onde se fundem em um ducto comum que se abre na fosseta anal, distalmente à linha pectinada. O epitélio secretor destas glândulas apresenta características de secreçäo holócrina

Histological and structural observations on pre-anal glands of the gekkonid lizard, Hemidactylus flaviviridis.

This paper describes a structural and histological study of the pre-anal glands of Hemidactylus flaviviridis. Only males possess these glands, which have a tubulo-acinar structure. They are holocrine in nature and become hyperactive during the breeding period. Thus they may be involved in the production of pheromones for socio-sexual communication.

Anatomic predisposition to perianal fistulae formation in the German shepherd dog.

Gross and microanatomic features which may predispose the German Shepherd Dog to perianal fistulae formation were studied in 2 groups of clinically healthy dogs: a predisposed group (German Shepherd Dogs) and a control group comprising breeds not ordinarily affected by perianal fistulae. The dimensions of the anal crypts (depth, base width, and length), measured and compared statistically between samples, identified no significant variation between groups (P greater than 0.05). Major tissue components of the anal canal were measured microscopically and were similarly evaluated: epithelial height in each zone, thickness of the lamina propria in each zone, thickness of the internal and external anal sphincter muscles, and density of the circumanal, sebaceous, and apocrine sweat glands. The only significant finding was an increase in density of apocrine sweat glands in the zona cutanea in the pre-disposed dog group. In a semiquantitative analysis of the inflammatory responses frequently seen in the anal glands, more mature fibroplasia was seen in the German Shepherd Dogs, indicating that inflammation was more longstanding in this group.

Carcinoma of the perianal gland and associated structures in 1,2-dimethylhydrazine treated mice.

Male C57BL/Icrf alpha t mice receiving long courses of weekly subcutaneous injections of 8.25 or 12.5 mg/kg, 1,2-dimethylhydrazine (DMH) developed perianal carcinomas as well as tumours at other sites. Tumours of the perianal gland or its associated hair root sheath and overlying skin included sebaceous gland adenocarcinomas, often with squamous metaplasia, analogous to those in the rat ear, and dysplasia, polyp formation and squamous cell carcinomas (SCC). Of 152 mice treated, 88 remained after 30 injections, and 10 out of a total of 14 tumours developed after 30 treatments. Perianal SCC without definite perianal gland association developed in 2 other animals.

The microscopic anatomy of epidermal glands in two species of gekkonine lizards, with some observations on testicular activity.

The gross and microscopic anatomy of epidermal glands has been studied in laboratory maintained tokays (Gekko gecko), and house geckos (Hemidactylus bowringii) captured from the wild throughout the year. Annual testicular activity in the house gecko has also been studied. While no significant differences in glandular development at various times have been observed in G. gecko, there are clear-cut annual cycles in H. bowringii. The evolution of epidermal glands in gekkonid lizards is reviewed; the cellular dynamics of beta-glands are compared with those of unspecialized epidermis; the possibility that gekkonine epidermal glands respond to quantitative variation in circulating testosterone titers is discussed.