Articular cartilage specimens from the distal articular surface of 32 radiocarpal bones from 24 2- to 5-year-old horses were analyzed. The total collagen content was determined on the basis of the 4-hydroxyproline content, using a colorimetric method. A method for estimating the proportions of types-I and -II collagen by measuringspectrophotometric densities of specific cyanogen bromide peptide bands from mixtures of types-I and -II collagen on sodium dodecyl sulfate-polyacrylamide gels was used. The cyanogen bromide peptides representative of each collagen types-I and -II were identified. The peptide ratios were then computed for each of several standards of type-I and -II mixtures. A standard curve was derived from the correlation between these ratios and the corresponding proportions of type-II collagen in standard mixtures. Galactosamine and glucosamine content (hexosamines) were measured by ion chromatography. Thegalactosamine-to-glucosamine ratio, chondroitin sulfate and keratan sulfate values, and total glycosaminoglycan content were derived from the measured hexosamine content. The total collagen content averaged 556 mg/g (55.6 mg/100 mg) of tissue (dry weight, [dw]). Type-II collagen was the major collagen type in normal articular cartilage specimens. The ratio of the area under the alpha 1 (II)CB10 peak to the area under the alpha 1 (I)CB 7,8 + alpha 1 (II)CB11 peak was a second-order polynomial function of the proportion of type-II collagen in the specimens. The mean galactosamine and glucosamine content were 20.6 mg/g and 7.9 mg/g (dw), respectively. The meangalactosamine-to-glucosamine ratio was 3.74 +/- 0.62. Chondroitin sulfate values, keratan sulfate values, and total glycosaminoglycan content were 53.3 +/- 4.9 mg/g, 19.9 +/- 3.6 mg/g, and 73.2 +/- 7.9 mg/g (dw), respectively. There was no significant correlation between the age of the horses and any of the chemical values (P>0.1). The biochemical composition of articular cartilage in the horse is similar to that of other species.

The aim of our study was to optimise an existing staining procedure: haematoxylin-eosin saffron (HES). The method follows the classical haematoxylin and eosin protocol with the addition of a staining step using natural saffron to better identify the collagen fibres. The saffron solution was obtained by dissolving ground saffron stigmas in absolute alcohol. In order to test the HES method for its staining ability on four main types of collagen (I, II, III, and IV), specific tissues (skin, tooth, cartilage, aorta, spleen, and penis) were chosen. The procedure showed a sharp differentiation between muscle, stained red or pink, and connective tissue, stained bright yellow or orange. HES allows the diagnosis of reticulin fibrosis undetected in HE and in previous saffron staining procedures. HES represents an advantageous alternative to HE staining giving highly reproducible results with high diagnostic value.

Introduction: The aim of the study was to examine the percentage volume of epithelium, acini, and interstitial collagen in the nonhyperplastic canine prostate and in cases of epithelial and epithelial cystic hyperplasia. Material and Methods: A histomorphometric study of 39 prostates was performed using computer image analysis. Results: The highest percentage volume of epithelium was found in cases of epithelial hyperplasia (47.8 %) and epithelial cystic hyperplasia was the correlate for acini (48.97 %). Epithelium decreased with dogs’ age (P < 0.01), whereas acini increased (P < 0.01). Interstitial collagen varied only insignificantly across age groups, but collagen was higher (12.1 %) in the nonhyperplastic prostates. With age cystic formation progressed in the canine prostate, the percentage volume of epithelium decreased and that of acini increased, but this same parameter in prostatic collagen did not change distinctly. The epithelium percentage volume increased in cases of epithelial hyperplasia but the cystic variant caused an increase in acinar volume. Conclusion: As dogs age, cystic formation progresses in the prostate, therefore the volume of epithelium decreases and that of acini increases. The volume of prostatic collagen did not change distinctly with age, and was higher in normal prostates than in both epithelial and epithelial cystic hyperplastic glands.

Introduction: The aim of the study was to examine the percentage volume of epithelium, acini, and interstitial collagen in the nonhyperplastic canine prostate and in cases of epithelial and epithelial cystic hyperplasia. Material and Methods: A histomorphometric study of 39 prostates was performed using computer image analysis. Results: The highest percentage volume of epithelium was found in cases of epithelial hyperplasia (47.8 %) and epithelial cystic hyperplasia was the correlate for acini (48.97 %). Epithelium decreased with dogs’ age (P < 0.01), whereas acini increased (P < 0.01). Interstitial collagen varied only insignificantly across age groups, but collagen was higher (12.1 %) in the nonhyperplastic prostates. With age cystic formation progressed in the canine prostate, the percentage volume of epithelium decreased and that of acini increased, but this same parameter in prostatic collagen did not change distinctly. The epithelium percentage volume increased in cases of epithelial hyperplasia but the cystic variant caused an increase in acinar volume. Conclusion: As dogs age, cystic formation progresses in the prostate, therefore the volume of epithelium decreases and that of acini increases. The volume of prostatic collagen did not change distinctly with age, and was higher in normal prostates than in both epithelial and epithelial cystic hyperplastic glands.

Mammary tumours are considered as the most important neoplasms in dogs especially in sexually intact female dogs. Prognosis is directly associated with various factors such as tumour size, metastases, involvement of lymph node, tumour type and grade. Recently, tumour microenvironment (TME) has gained huge importance and proved to be a key regulator of breast cancer's biologic behaviour, according to mounting data. The capacity of extracellular matrix components like collagen to alter their intrinsic structure and alignment aids in tumour invasion and metastasis. We present a case study of 25 canine mammary tumours (CMTs), where the stroma associated with the malignancy was specifically considered while histomorphologically analysing the tumours. The majority of the tumours were malignant (96 per cent) and one was identified to be benign. Simple carcinomas made up the majority of tumours, followed by mixed types. Cancer associated stroma was assessed by routine H and E staining and additionally by performing immunohistochemistry technique with anti-cytokeratin antibody to access the relative abundance of neoplastic epithelial cells. Special stains such as Picrosirius red, Masson’s trichrome and Herovici were employed to demonstrate the desmoplastic stromal reaction and varying grades of collagen could be observed in the stroma of different tumours. The extent of fibroplasia was found to be directly proportional to the grade and size of tumour. Thus, results of the present study indicated that the cancer associated stroma significantly in fluence the CMT progression and clinical outcome.

OBJECTIVE To examine the effects of imidazoline and nonimidazoline α-adrenergic agents on aggregation of feline platelets. SAMPLE Blood samples from 12 healthy adult cats. PROCEDURES In 7 experiments, the effects of 23 imidazoline and nonimidazoline α-adrenoceptor agonists or antagonists on aggregation and antiaggregation of feline platelets were determined via a turbidimetric method. Collagen and ADP were used to initiate aggregation. RESULTS Platelet aggregation was not induced by α-adrenoceptor agonists alone. Adrenaline and noradrenaline induced a dose-dependent potentiation of ADP- or collagen-induced aggregation. Oxymetazoline and xylometazoline also induced a small potentiation of ADP-stimulated aggregation, but other α-adrenoceptor agonists did not induce potentiation. The α2-adrenoceptor antagonists and certain imidazoline α-adrenergic agents including phentolamine, yohimbine, atipamezole, clonidine, medetomidine, and dexmedetomidine inhibited adrenaline-potentiated aggregation induced by ADP or collagen in a dose-dependent manner. The imidazoline compound antazoline inhibited adrenaline-potentiated aggregation in a dose-dependent manner. Conversely, α1-adrenoceptor antagonists and nonimidazoline α-adrenergic agents including xylazine and prazosin were ineffective or less effective for inhibiting adrenaline-potentiated aggregation. Moxonidine also was ineffective for inhibiting adrenaline-potentiated aggregation induced by collagen. Medetomidine and xylazine did not reverse the inhibitory effect of atipamezole and yohimbine on adrenaline-potentiated aggregation. CONCLUSIONS AND CLINICAL RELEVANCE Adrenaline-potentiated aggregation of feline platelets may be mediated by α2-adrenoceptors, whereas imidazoline agents may inhibit in vitro platelet aggregation via imidazoline receptors. Imidazoline α-adrenergic agents may have clinical use for conditions in which there is platelet reactivity to adrenaline. Xylazine, medetomidine, and dexmedetomidine may be used clinically in cats with minimal concerns for adverse effects on platelet function.

OBJECTIVE To assess effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product for the treatment of experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana). ANIMALS 16 healthy subadult green iguanas. PROCEDURES Iguanas were anesthetized, and three 5-mm cutaneous biopsy specimens were obtained from each iguana (day 0). Iguanas were randomly assigned to 2 treatment groups, each of which had a control treatment. Wounds in the topical treatment group received silver sulfadiazine, a topical antimicrobial product, or no treatment. Wounds in the laser treatment group received treatment with a class 4 laser at 5 or 10 J/cm2 or no treatment. Wound measurements were obtained daily for 14 days. Iguanas were euthanized, and treatment sites were evaluated microscopically to detect ulceration, bacterial contamination, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity. RESULTS On day 14, wounds treated with a laser at 10 J/cm2 were significantly smaller than those treated with silver sulfadiazine, but there were no other significant differences among treatments. Histologically, there were no significant differences in ulceration, bacterial infection, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity among treatments. CONCLUSIONS AND CLINICAL RELEVANCE Photobiomodulation at 10 J/cm2 appeared to be a safe treatment that was tolerated well by green iguanas, but it did not result in substantial improvement in histologic evidence of wound healing, compared with results for other treatments or no treatment.

OBJECTIVE To characterize the MRI and histologic features of the supraspinatus tendon in nonlame dogs. ANIMALS 7 cadavers (14 shoulder joints) of nonlame 2-year-old sexually intact male Beagles. PROCEDURES Multiple MRI fluid-sensitive pulse sequences were obtained for both shoulder joints of each cadaver, and the thickness, volume, and signal intensity of each supraspinatus tendon were assessed. After MRI scanning was complete, the shoulder joints were processed for histologic examination. Tissue specimens were stained with various stains to determine tendon morphology and composition. Histologic and MRI findings were correlated and described. RESULTS All supraspinatus tendons had a trilaminar appearance on sagittal and transverse MRI images, which was characterized by a thick, hyperintense center layer (central substance) sandwiched between thin hypointense superficial and deep margins. The mean ± SD central substance-to-superficial margin and central substance-to-deep margin thickness ratios were 8.4 ± 1.2 and 9.0 ± 0.9, respectively; supraspinatus tendon-to-triceps brachii muscle signal intensity ratio was 1.3 ± 0.2; and tendon volume was 445 ± 20 mm3. The superficial and deep margins histologically resembled other tendons with highly ordered collagen fibers. The central substance was comprised of water-rich glycosaminoglycans interspersed among haphazardly arranged collagen bundles. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated histologically normal canine supraspinatus tendons have a trilaminar appearance on MRI images. In dogs, a diagnosis of supraspinatus tendinosis should not be based solely on the tendon having a hyperintense signal on MRI images; other MRI evidence of shoulder joint disease and diagnostic findings are necessary to support such a diagnosis.

The digital cushion (DC) plays a role in absorbing and dampening forces applied to the foot and therefore supports internal structures such as navicular bone; yet, its architecture is not well-known. The goal of this study was to characterize the microanatomical structure of the DC in horses with clinically sound hooves. Both forefeet from the cadavers of 12 adult Quarter horses were cut and sectioned and samples of the following 4 regions of the DC were obtained: axial proximal (AxProx), axial distal (AxDis), abaxial lateral (AbxLat), and abaxial medial (AbxMed). The samples were processed and stained with hematoxylin and eosin, Masson's trichrome, and Weigert's elastic stains. On each slide, 2 central 3- × 3-mm areas were microscopically assessed and all measurements were done within the 9-mm2 area. The number of detected collagen bundles, nerve fascicles, vessels, and the diameter of wall thickness and lumen of blood vessels were measured. Elastic fiber profiles were categorized based on relative density of elastic fibers detected in the field. The percentage of samples in which chondrocytes and adipose tissues were either present or absent was calculated. Significant structural differences were identified among the 4 regions of the DC. The AxDis region contained more collagen bundles (P < 0.0001) and less elastic fiber profiles than the AxProx region (P < 0.0001). The AxDis also contained more collagen bundles than the AbxMed and AbxLat (P < 0.0001) regions. Our findings provide insight into the structure of the DC of mature Quarter horses. The structural differences in the various regions of the DC are presumably related to the different functional properties of those regions; yet more research is warranted.