Estructura del estroma conjuntivo del epidídimo del bovino cebú (Bos indicus)

Six adult Zébu cattle were used for a study of the histologic structure of the epididymus. Tissues were fixed in neutral formalin or in Bouin's solution. Tissues were prepared with parafin sectioning and stained with hematoxylin and eosin, Masson and Mallory's trichrome stain and with aldehyde fuchsin and Gomori's argentamine stains. The structure of the connective tissue stroma is described and compared with that of other mammals. The presence of smooth muscle within the stroma and within the tunica albuginea is described for the Zébu.     

Anatomy and Cholinergic Innervation of the Sinus paranalis in Dogs

Conventional methods have been used to study the general configuration of the wall of the Sinus paranalis in dogs. Apocrine tubular glands, elastic fibres and smooth-muscle fibres are the more significant elements of the wall, together with the epithelium and connective tissue. By means of the immunohistochemical method described in this paper, the results provide histochemical evidence for the presence of an AChE-positive reaction, and supposedly cholinergic nerve fibres in the wall of the dog anal sacs, mainly associated with subepithelial smooth muscle, vessels, and glands.     

Über die intramuralen Blutgefäße des Enddarms vom Pferd (Equus przewalskii f. caballus)

The vascular system of the large intestine of 12 horses was examined by means of vascular corrosion casts, histology and transmission electron microscopy providing the following results. The Aa. et Vv. breves et longae leave the mesenteric vessels, respectively the subserously on the teniae lying cecal vessels to reach the tela subserosa at the mesenteric margin. The short vessels enter the deeper layers of the wall instantly, whereas the Aa. et Vv. longae move towards the submucosa by penetrating the muscular layers after a variable subserous course. The tela submucosa contains an arterial and a venous vascular plexus. In broader areas of the submucosa a three-dimensional vascular network can be found. This consists of a deep and a superficial vascular plexus, which are closely interconnected. The deep plexus is applied to the inner circular muscles, whereas the superficial plexus is adjacent to the muscularis mucosae. The (deep) arterial plexus receives its afflux from the Aa. breves et longae and supplies parts of the circular muscle layer with recurrent muscle branches. The vascularisation of the mucosa also originates from the submucosal (superficial) plexus. In the basal tunica mucosa, the ascending arteries form a transversal network from which arterioles branch into periglandular capillaries around each Lieberkühn crypt. Close to the lumen, a polygonal subepithelial capillary system is formed. The capillaries turn into postcapillary venules immediately below the epithelium of the mucosal surface. Veins move vertically through the submucosa to enter the submucosal plexus after few inflowing side branches. Branches of the subserous-submucosal connections form an intermuscular plexus between the circular and longitudinal muscular layer. This plexus supplies the capillaries of the tunica muscularis. The subepithelial capillaries are predominantly lined with a fenestrated endothelium, whereas the capillaries of the pericryptal mucosa mainly show a continuous endothelial lining. The latter contain multiple vesicles, which may fuse in order to form transcytoplasmic channels. Sphincter-like muscle bundles at the transition points from capillaries to venules may provide hemodynamic regulatory structures in the submucosa of the horse. Veins with circumferential cushions of smooth muscle fibres, so-called ‘throttle veins’, are also found.     

La vascularisation du feuillet du boeuf)

The blood vascular system of the bovine omasum The blood vessels supplying and draining the omasal wall and laminae are described and are compared with those of other ruminants. A detailed study revealed that the subepithelial vascular networks in the papillae were in part similar to those of intestinal villi. One or more arterioles branch radially and form a capillary network which does not, as in the villus, drain into a central venule but is succeeded by several subepithelial venules. Capillaries and venules differ only in diameter which are 10 μm. and 40 μm. respectively. The walls of both have a complete basal membrane, perforated endothelium and pinocytotic vesicles. This emphasizes their significance in resorption. Inside and between the papillae the capillaries form a dense network which is separated from the basal cells by a thin layer of connective tissue 5 to 6 μm. thick. Hemodynamic problems related to the presence of elastic connective tissue and to the motor activity of the omasum are discussed.     

Histological and ultrastructural studies on the coronary artery of adult domestic dog (Canis familiaris)

The objective of this work was to study the histological structure of the dog's coronary artery by light and transmission electron microscope (TEM). The coronary artery consisted of three tunics: tunica intima, tunica media and tunica adventitia. The tunica intima consisted of endothelium rested directly on internal elastic lamina without the subendothelial connective tissue layer. The tunica media were composed of smooth muscle fibres interspersed with few elastic and collagen fibres. The tunica adventitia consisted of collagen and elastic fibres intermingled with fibroblast cells; it had vasa vasorum and nervi vasorum. Some histomorphometric measurements were performed and compared statistically. The ultrastructural study showed that the endothelial cells were communicated through complex junctions and characterised by filiform cytoplasmic processes passed through the opening of the underlying internal elastic membrane. The smooth muscle fibres of tunica media communicated with each other through cytoplasmic processes. The tunica adventitia showed minute non-myelinated nerve. This work revealed that the dog's coronary arteries are typical muscular arteries, which show little structural variations from that of other mammals.     

Organisation of Autonomic Nervous Structures in the Small Intestine of Chinchilla (Chinchilla laniger,Molina)

Using histochemical, histological and immunocytochemical methods, organisation of the autonomic nerve structures in small intestine of chinchilla was investigated. Myenteric plexus was localised between circular and longitudinal layers of the smooth muscles. Forming network nodes, the small autonomic, cholinergic ganglia were linked with the bundles of nerve fibres. Adrenergic structures were visible as specific varicose, rosary‐like fibres forming bundles of parallel fibres connecting network nodes. Structures of the submucosal plexus formed a finer network than those of the myenteric plexus. Moreover, in ‘whole‐mount’ specimens, fibres forming thick perivascular plexuses were also observed. Immunocytochemical studies confirmed the cholinergic and adrenergic character of the investigated structures. VAChT‐positive neurones were found only in myenteric plexus, and numerous VAChT‐positive and DBH‐positive fibres were found in both plexuses.     

TRANSITIONAL CELL CARCINOMA OF THE URETHRA IN FOUR FEMALE DOGS: ITS URETHROGRAPHIC APPEARANCE

ansitional cell urethral carcinoma in four female dogs is reported. Lesion distribution in the proximal two thirds of the urethra and the radiographic appearance with retrograde positive contrast urethrography were similar in each dog. The normally smooth longitudinal urethral striations were replaced by multiple small, poorly marginated intraluminal masses that resulted in a generalized moth-eaten appearance. Extension of contrast medium into the periurethral tissues also occurred. Retrograde urethrography, a simple diagnostic technic, aided in establishing a differential diagnosis in dogs that had urine retention and stranguria.     

Histological Assessment of Selected Blood Vessels of the Phocid Seals (Northern Elephant and Harbour Seals)

Phocid seals exhibit vascular adaptations that allow them to undertake prolonged deep dives. These vascular adaptations are either unique to phocids, or are modified vascular equivalents to those present in terrestrial mammals. One such adaptation, the aortic bulb, is a spherical enlargement of the ascending aorta specific to phocid seals. Its histological make‐up consists of a reinforced tunica media with circular and longitudinal layers of elastic fibres. This reinforcement enables multi‐axial deformation of the aortic bulb, thus complementing its function as a prominent elastic reservoir or ‘windkessel’. A second adaptation, the hepatic sinus, is an asymmetrical dilation of the abdominal portion of the caudal vena cava and accompanying hepatic veins. The hepatic sinus is comprised of a relatively thin tunica media, with a scant smooth muscle component. The bulk of the sinus wall is comprised of tunica adventitia. A third vascular adaptation distinctive to the phocids is the pericardial venous plexus, composed of convoluted veins circumnavigating the perimeter of the heart. Microscopically, these veins have a thick tunica media and also contain valves. Smaller arteries, venules and distinct capillary beds are observed interspersed in‐between these veins. It can be hypothesized, that in seals, certain vascular embryonic development may be arrested at an earlier embryonic stage, resulting in these unusual vascular formations. These modifications play a vital role in blood pressure regulation and distribution of oxygenated blood during prolonged deep diving. The purpose of this work was to elucidate the histological aspects of these unique vascular modifications and relate them to specific function.     

The problematic nature of ectopic corpora lutea

For educational reasons, 50 bovine ovaries were collected and macroscopically examined. In one case a well developed corpus luteum was seen as a separeted organ that was connected to the ovary by a delicate bridge of connective tissue. This excepctional material was preserved by formalin fixation, photographed and microscopically examined. Blood supply of the ectopic corpus luteum was provided by three arteries wich approached from the ovary by way of the delicate connective tissue bridge. The arteries penetrated into the parenchyma, ramified and feedes a system of sinusoid capillaries as usually seen in corpora lutea. Draining veins were remarkably thin-walled, they emtied into a venous plexus at the surface of the ectopic organ. The importance of the intensive vascularization of the corpus luteum at least should be considered new, with regard to the results of these examinations.     

Oxytalan fibres in the periodontal ligament of equine molar cheek teeth

The distribution and arrangement of oxytalan fibres were examined in periodontal specimens of cheek teeth from seven horses. Oxidation prior to aldehyde fuchsin exposition permitted a selective staining of the oxytalan fibres, which are a distinct component of the elastic fibre system. On three horizontal levels of the periodontium--(a) subgingival, (b) middle third and (c) apical--two oxytalan fibre groups were shown histologically: 'blood vessel-related' and 'independent' oxytalan fibres. In levels a and b, both groups were arranged in a typical occluso-apical alignment along the reserve crown. Single oxytalan fibres deviated from their general course in order to attach to the cementum. In these cemental entheses the oxytalan fibres ran parallel to collagen fibre bundles. The interpretation of such morphological features emphasized the oxytalan fibres' capacity to improve the stability of periodontal blood vessel walls during masticatory movements. Level c, especially in regions next to the persisting epithelial root sheath, is the site of oxytalan fibre generation. This is a prerequisite for the facilitation of periodontal regeneration and reorganization during dental growth and eruption.     

The teniae of the equine intestinal tract.

At several locations along the equine cecum and colon, the outer longitudinal portion of the tunica muscularis is gathered into discrete bands of smooth muscle and connective tissue called "teniae". In this study, the disposition of the teniae ceci and coli was traced along the equine intestinal tract. It was discovered that, in several instances, arrays of teniae converge toward the valves and sphincters which separate the various intestinal compartments. The teniae may also provide support for and directionality to, peristaltic contraction waves. The tissue proportions of the teniae vary in different locations. The tenia libera lateralis of the ventral colon is rich in elastic connective tissue, while that of the right dorsal colon is primarily composed of smooth muscle. This may reflect the different responsibilities of these two compartments. The teniae are innervated and their smooth muscle cells are joined by many gap junctions. The connective tissue constituents afford intestinal support while yielding to intestinal distension. The smooth muscle and neural elements may foster active tenial participation in peristalsis. This premise must be tested by electrophysiological experimentation. Further experimentation is also necessary to ascertain whether injury to the teniae might predispose a horse to colic.     

Localization of hyaluronic acid in the seminal vesicles of the miniature pig

We studied the detailed localization of hyaluronic acid in the seminal vesicles of the miniature pig, using hyaluronic acid-binding protein as a specific histochemical probe at the ultrastructural level. According to the results, the basolateral surface of the plasma membrane of the glandular epithelial cells, was found to contain hyaluronan. However, abundantly present was hyaluronan in the subepithelial connective tissue, in particular, in the extracellular matrix surrounding the fibroblasts, smooth muscle cells, small blood vessels and capillaries. The substance was also observed in the surface coat of the plasma membrane of the fibroblasts, but not in that of the smooth muscle cells. The findings suggest that hyaluronan in the seminal vesicles of the miniature pig is synthesized onto the surface coat of the plasma membrane of the fibroblasts, is contributed to the extracellular matrix, and consequently concentrates in the subepithelial connective tissue. The substance may particularly be involved in a variety of cellular functions to maintain morphological organization as well as to regulate physiological homeostasis in the reproductive organ of this species, rather than participate in sperm functions.     

Surgical Management of Congenital Urethral Sphincter Mechanism Incompetence in Eight Female Cats and a Bitch

Congenital urethral sphincter mechanism incompetence is a cause of urinary incontinence in female dogs and cats. In some of these animals, urethra hypoplasia is the primary diagnosis, with the urethra being almost absent in some patients. Treatment of this problem can be difficult. This paper describes two techniques for the surgical treatment of eight cats and one dog with severe urethral hypoplasia. In five animals, partial excision of the bladder neck was performed to create a longer "urethra." In the other four, an attempt was made to conserve bladder volume while simultaneously creating a urethra with a bladder neck flap reconstruction technique. One cat was lost to follow-up, but the clinical signs resolved in three cats and the remaining animals improved. Two cats had recurring cystitis, possibly associated with bladder neck diverticula because of uterine horn remnants terminating abnormally in the bladder. The results in this limited series suggest that reconstructive surgery in cases of severe urethral hypoplasia improves continence control.     

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.     

Micromorphology of the skin (epidermis, dermis, subcutis) of the dog

Grossly, the skin of the dog is characterized by varying thicknesses, density of the hair coat and the implantation angle of the hairs. Multiple folds varying in shape are formed by the epidermis and the papillary layer of the corium. The epidermis consists of a stratum profundum with a continuous layer of basal cells, a stratum spinosum consisting of 3-6 cell layers, a stratum superficiale with single granulosa and "lucidum" cells and a well-developed stratum corneum. The corium shows a narrow stratum papillare corli containing delicate fibres and a broad stratum reticulare corii with mainly coarse fibre bundles. The subcutis is divided into adipose and fibrous layers. The broad adipose layer displays breed and individual differences which vary with the region of the body. The fibrous layer corresponds to the connective tissue layer, formerly described as fascia trunci superficialis. The morphological and functional unity of the corium and subcutis is discussed.     

The microvascularization of the penis of the steer (Bos taurus)]

The blood supply and the microvascularization of the bovine penis (Bos taurus) were demonstrated using the scanning electron microscope. The Corpus cavernosum penis of the bull consists of a surprisingly well-developed mesh of small to intermediate vessels. The architecture of the cavernous body is largely determined by trabeculae of connective tissue, the extent of which varies between penis segments. The Corpus cavernosum is arranged primarily as a ring around the trabeculae of connective tissue. Chambers of large bore are found in the central portions of the Corpus cavernosum penis, whereas a relatively fine vascular network predominates in the periphery. Vessels in the cavernous body of the urethra, on the other hand, show strictly parallel orientation to the urethra, which they surround like a sleeve. They also stand in close association with vessels in the outer layer of the Tunica albuginea. The vascular systems of the Corpus cavernosum penis and the Corpus spongiosum penis are not connected with one another. The vascular architecture of the Glans penis is characterized by the inclusion of well-developed vascular arcades at regular intervals. These course through a connective tissue matrix rich in glycoproteins and stretch to just under the skin of the penis, where they are intimately associated with a subpapillary network of arteries and veins. The venous legs of the vascular arcades are supplied by this network of veins. The Glans penis of the bull is considered to represent a specialization of the penile integument.     

Carbon fibres and plasma-preserved tendon allografts for gap repair of flexor tendon in bovines: gross,microscopic and scanning electron microscopic observations

The efficacy of carbon fibres and plasma-preserved tendon allografts for gap repair in the superficial digital flexor tendon in the mid-metatarsal region was evaluated in 12 crossbred calves. Experimental tenectomies were performed, followed by implantation of carbon fibres in group I (12 legs) and plasma-preserved tendon allografts in group II (12 legs). Gross observations in group I showed filling of the defect with granulation tissue with more vascularity on day 7, which was less prominent at day 14. On day 30, the neotendon formed was slightly thicker and comparable to normal tendon in appearance and texture. On day 90, it exhibited all the characteristics of a fully developed tendon. Whereas, in group II increased vascularity at the site and encapsulation of the graft with connective tissue in early periods was observed. The gap between graft and host was filled with fibrous connective tissue. Peritendinous adhesions were maximum on day 7 which were gradually reduced in both groups. Microscopically, an acute inflammatory reaction in the periphery of carbon fibres was observed on day 7. Immature fibroblasts were arranged in a haphazard pattern at this stage. By day 14, numerous newly formed capillaries and comparatively more mature fibroblasts were present in between and around the carbon fibres which were aligning parallel to the longitudinal axis of the tendon. By day 30 the healing tissue exhibited longitudinal orientation of collagen fibres and was at a more advance stage of maturation. By day 90, the neotendon formed simulated the picture of normal tendon. In the grafted tendon group, there was normal healing tissue at the functional sites between host and grafted tendon. The fibroblastic activity appeared to be both extrinsic and intrinsic in origin. The connective tissue had invaded the graft to a variable distance and there was resorption of graft which was replaced by newly formed connective tissue on day 90. Scanning electron microscopic observation revealed formation of neotendon between carbon fibre strands, resulting in thickening of the implant. In later stages parallel collagen fibres resembling normal tendon were observed in both groups.     

Long-Term Efficacy of a Percutaneously Adjustable Hydraulic Urethral Sphincter for Treatment of Urinary Incontinence in Four Dogs

Objective— To evaluate the efficacy of a surgically placed, static hydraulic urethral sphincter (SHUS) for treatment of urethral sphincter mechanism incompetency (USMI).
Study Design— Prospective study.
Animals— Spayed female dogs (n=4) with acquired USMI.
Methods— Urinary incontinence was assessed using a subjective continence score before and after implantation of an SHUS on the proximal urethra via ventral median celiotomy. Dogs were assessed for urinary continence, urinary tract infections, and implant-associated complications for 30 months. Residual incontinence was treated with percutaneous inflation of the SHUS with sterile saline solution through a biocompatible subcutaneous administration port.
Results— At last follow-up (26–30 months after surgery), continence scores improved from a median preoperative score of 3/10 to a median postoperative score of 10. One dog developed wound drainage over the subcutaneously placed administration port but remained continent after port removal. Three occluders were percutaneously filled with additional saline (median, 0.18 mL; mean, 0.16 mL) to improve continence after surgery.
Conclusions— Application and adjustment of an SHUS provided sustained improvements in continence score in all dogs.
Clinical Relevance— In this pilot study, 3 of 4 dogs with hydraulic urethral sphincter implantation had successful percutaneous adjustment and maintained improved continence scores for 2 years after surgery. Continence was maintained in the 4th dog even after administration port removal. Based on this pilot study, the SHUS warrants further clinical evaluation for treatment of dogs with USMI unresponsive to medical management.     

How many Layers has the Adventitia? – Structure of the Arterial Tunica Externa Revisited

Tunica adventitia or tunica externa is the outer layer of the blood vessel wall. It consists of connective tissue with vasa and nervi vasorum and plays a key role in vascular health. The aim of our study was to compare the wall layers beyond tunica media in arteries of different type and location. The following arteries of pig, dog and cat were processed histologically and analysed by light microscopy: aorta ascendens, arcus aortae, aorta thoracica, aorta abdominalis, arteria (a.) femoralis, a. tibialis cranialis, a. carotis communis, a. lingualis, a. basilaris, a. cerebralis media, a. testicularis and aa. jejunales. We found two layers of connective tissue outside the media: (1) a compact layer with many elastic fibres in muscular and few in elastic arteries and (2) an outer layer of loose connective tissue. The compact layer was missing in aorta ascendens, arcus aortae and intracranial vessels. Adventitial stripping removed only the loose connective tissue layer. In spite of the still present compact layer, stripped arteries were very flimsy. We suggest using the term ‘tunica externa’ for the compact connective tissue layer and ‘tunica adventitia’ for the outermost loose connective tissue layer as in other organs. The presence of the tunica externa differs between species, arteries and arterial side, as well as the removability of tunica adventitia and tunica externa by anatomical dissection.     

The histological observations on the large intestine of the goose (Anser anser) during the pre- and post-hatching periods

The development of the cecum and colon in the goose was investigated during the period from the 15th to 28th day of the incubation and from 1 to 30 days of age after hatching by light microscopy. By day 15 of the incubation, in the cecum and colon, the lumen was surrounded by pseudostratified epithelium. The previllous ridges appeared at 15th and 17th days of the incubation in the colon and ceca, respectively. At the base of previllous ridges, the epithelium changed into a simple prismathic epithelium at 15th and 17th days of the incubation in the colon and cecum, respectively. The villi appeared at the 21st days of the incubation. The crypts and goblet cells appeared on the first day after hatching. In the pre-hatching period, the lamina muscularis mucosa was present only in the colon. The submucosa consisted of loosely aggregated connective tissue in the pre-hatching period. In the post-hatching period, it consisted of a very thin layer of connective tissue. Its presence was only obvious where the cells of the submucosal nerve plexus or occasional large blood vessels considerably increased its thickness. The nerve plexus corresponding to the Auerbach's plexus of the mammalian intestine and submucosal nerve plexus appeared by 15th days of the incubation. From the 15th to 28th day of incubation, the tunica muscularis consisted of circular smooth muscle cells in the ceca. On the 28th day of the incubation a thinner longitudinal muscle layer added to the circular muscle layer. In the colon there was an outer longitudinal and a thicker circular muscle layer.