Spontaneously Arising Tumours and Tumour-like Lesions of the Cervix and Uterus in 83 Pet Guinea Pigs (Cavia porcellus).

Tumours and tumour-like lesions are rare findings in the genital system of guinea pigs. The aim of the present study was to characterize nodular lesions in the cervix and uterus of guinea pigs submitted for histopathological diagnosis. Samples from 83 pet animals were investigated. Cases included 64 surgically excised masses including complete uteri (n = 37), parts from uteri containing masses (n = 8), complete masses (n = 12) or samples from masses (n = 7) and 19 complete necropsy examinations. In 55 of the cases, only solitary changes were observed; in 28 cases two or more lesions were diagnosed. Histopathological diagnoses included polyps in the vagina, cervix or uterus (n = 8), hyperplastic lesions of the endocervix (n = 10) and seven adenomas and two adenocarcinomas of the endocervix. Endometrial alterations included single small glandular cysts (n = 3), nodular glandular-cystic hyperplasia (n = 8), adenoma (n = 20) and adenocarcinoma (n = 3). Four placentas, 10 focal decidualizations and six deciduomas were found. Furthermore, 18 leiomyomas and nine leiomyosarcomas were diagnosed. Uterine malignant mixed Müllerian tumours were observed in seven cases. Overall, benign lesions outnumbered malignant tumours in the female genital tract of pet guinea pigs. Therefore, surgical excision or ovariohysterectomy should be recommended as therapy.

Cutaneous and Subcutaneous Soft Tissue Tumours in Snakes: A Retrospective Study of 33 Cases.

Cutaneous and subcutaneous soft tissue tumours have been rarely described in detail in snakes. Several malignant entities show strikingly similar histological patterns and therefore the term soft tissue sarcoma (STS) has become a standard histopathological diagnosis. The present study characterizes soft tissue tumours in 33 snakes. Samples included 29 surgically excised masses and four carcasses. Additionally, six animals were humanely destroyed and submitted for necropsy examination following tumour recurrence. Benign neoplasms (n = 8) were described as lipomas of varying differentiation. Recurrence was observed in two of five snakes in which the clinical course was recorded. Malignant neoplasms (n = 25) were diagnosed as STS and graded according to a three-point system previously applied to canine STS. Five (20%) of the primary tumours were classified as grade 1, eleven (44%) as grade 2 and nine (36%) as grade 3 sarcomas. Clinically, recurrence of STS was observed in 11 of 17 cases with available follow-up information. Pathologically, multiple cutaneous metastases were found in one grass snake (Natrix natrix), while visceral metastases were observed in one carpet python (Morelia spilota) and two corn snakes (Pantherophis guttatus). Metastatic risk appears to increase with histological grade. Surgical excision generally represents the current therapy of choice for STS. This study includes the first reports of conventional lipomas in a ribbon snake (Thamnophis radix), angiolipomas in a black-headed python (Aspidites melanocephalus) and a corn snake as well as of STS in a Jamaican boa (Epicrates subflavus), emerald tree boa (Corallus caninus), grass snake (N. natrix), African house snake (Lamprophis fuliginosus), California kingsnake (Lampropeltis getula californiae) and common garter snake (Thamnophis sirtalis).

Alpha-smooth muscle actin and serotonin receptors 2A and 2B in dogs with myxomatous mitral valve disease.

Canine Myxomatous mitral valve disease (MMVD) is an age-related disease. Serotonin (5-HT) is implicated in the pathogenesis as locally-produced or platelet-derived. Involvement of the 5-HT2A receptor (R) and 5-HT2BR in the induction of myxomatous-mediating valvular myofibroblasts (MF) has been suggested. In an age-matched population of dogs with non-clinical and clinical MMVD, the objectives were to investigate (1) gene expression of 5-HT2AR and 5-HT2BR, (2) protein expression and spatial relationship of 5-HT2AR, 5-HT2BR and MF in the mitral valve (MV) and the cardiac anterior papillary muscle (AP) and (3) serum 5-HT concentrations. Gene expression of 5-HT2BR was significantly higher in MV and AP among dogs with clinical MMVD. This was not found for 5-HT2BR protein expression, though association of 5-HT2BR with myxomatous pathology and co-localization of 5-HT2BR and MF in MV and AP support a functional relationship, perhaps perpetuation of clinical MMVD. 5-HT2AR-expression and serum 5-HT showed no differences between groups.

[Bone tumours in lizards and snakes. A rare clinical finding]. / Knochentumoren bei Echsen und Schlangen. Ein seltener klinischer Befund in der Reptilienpraxis.

OBJECTIVE: This article presents the pathological findings of 13 bone and cartilage tumours in lizards (n=8) and snakes (n=5) within the clinical context. MATERIAL AND METHODS: Within a 12-year period (2001-2013), 13 cases of bone tumours in reptiles were diagnosed from 358 submitted tumour specimens. Pathological examination was performed on eight excisions, two biopsies, two amputates and four carcasses. Macroscopically, the samples displayed a light-coloured surface when cut and had a generally solid consistency. For the histological examination, representative specimens were decalcified when necessary, embedded in paraffin and stained using haematoxylin and eosin. Diagnosis was made based on the World Health Organisation classification for veterinary and human medicine. RESULTS: Benign proliferations of the bone (ossifying fibroma [n=2], fibrous dysplasia [n=1]) as well as malignant cartilage (chondrosarcoma [n=2]) and bone tumours (fibroblastic osteosarcoma [n=2], small cell osteosarcoma [n=1]) were found on the head (n=5) and limbs (n=3) of various lizard species. In snakes only malignant cartilage neoplasms (chondrosarcoma [n=2], dedifferentiated chondrosarcoma [n=3]) of the spine were diagnosed. The histological appearance of the malignant tumours ranged from low to highly malignant differentiated aggregations of tumour cells, that produced varying amounts of osteoid or a hyaline matrix. Curative therapy was achieved in one ossifying fibroma by complete surgical removal and in two chondrosarcomas through amputation. No metastasis was observed in any of the four necropsies. CONCLUSION AND CLINICAL RELEVANCE: Primary neoplasias of the bone are rare tumours in reptiles. Considering the information on therapeutic procedures and clinical course, the therapy of choice in lizards is complete surgical removal whereas in snakes reductive surgery may prolong the survival time.

Matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs) and transforming growth factor-ß (TGF-ß) in advanced canine myxomatous mitral valve disease.

This study investigated mitral valve and myocardial protein and gene expression of matrix metalloproteinases (MMPs), their tissue inhibitors (TIMPs) and transforming growth factor-ß (TGF-ß) and plasma MMP and TGF-ß concentrations in age-matched dog groups euthanized due to either advanced myxomatous mitral valve disease (MMVD) or other reasons. Furthermore, echocardiographic data and lumen/area ratio were correlated with tissue and plasma levels of MMPs, TIMPs and TGF-ßs. Mitral valve and myocardial gene expression of MMP2, MMP14, TGF-ß1 and TGF-ß2 were increased and plasma MMP9 was decreased in advanced MMVD dogs. Myocardial gene expression of TIMP2 and TIMP3 were increased in advanced MMVD. All affected markers correlated to echocardiographic parameters. Significantly narrowed lumen/area ratio was associated with increased myocardial expression of MMP2, MMP14, TIMP2 and TIMP3. No differences in tissue protein expression were recorded. MMP2, MMP14, TIMP2, TIMP3, TGF-ß1 and TGF-ß2 appear to play a local role in the development of advanced MMVD.

Melanophoromas and iridophoromas in reptiles.

Chromatophoromas are tumours of pigment-producing cells of the skin and are rarely reported in reptiles. These tumours are subclassified on the basis of the type of pigment. The present study characterizes chromatophoromas arising in 26 reptiles, including six snakes, 19 lizards and a tortoise. These include the first reports of melanophoromas in a yellow anaconda (Eunectes notaeus), pigmy rattlesnake (Sistrurus spp.), southern water snake (Nerodia fasciata), veiled chameleon (Chamaeleo calyptratus) and leopard gecko (Eublepharis macularius); the first reports of benign iridophoromas in a savannah monitor (Varanus exanthematicus), veiled chameleon and bearded dragon (Pogona vitticeps); and the first description of a malignant iridophoroma in a bearded dragon. Additionally, in three bearded dragons a 'mucinous' type of melanophoroma is described for the first time. Chromatophoromas generally arose from the skin of the body and head and ranged in size from 0.2 to 2.0cm in diameter. In six cases the animals were humanely destroyed immediately after diagnosis. Three further animals were humanely destroyed following recurrence of their tumour. Six of these nine reptiles had visceral metastases. Grossly, melanophoromas (n=20) were grey or black, while iridophoromas (n=6) were white in colour. Microscopically, most of the tumours were composed of spindle cells with varying pigmentation and 0-2 mitoses per 10 high power fields. Six of the 20 melanophoromas were classified as malignant due to the presence of intravascular tumour cells, visceral metastases, high pleomorphism and/or mitotic figures. Five of the six iridophoromas were classified as benign and the one malignant tumour was defined by the presence of intravascular tumour cells and visceral metastases. Immunohistochemically, melan A and S100 were coexpressed by all of the chromatophoromas.

Cardiac remodeling and MMPs on the model of chronic daunorubicin-induced cardiomyopathy in rabbits.

The matrix metalloproteinases (MMPs) play a key role during cardiac remodeling. The aim of the study was to investigate the changes in collagenous proteins and MMPs in the model of non-ischemic, anthracycline-induced chronic cardiomyopathy in rabbits using both biochemical and histological approaches. The study was carried out in three groups of Chinchilla male rabbits: 1) daunorubicin (3 mg/kg, once weekly for 10 weeks), 2) control (saline in the same schedule), 3) daunorubicin with the cardioprotectant dexrazoxane (60 mg/kg, before each daunorubicin). Morphological changes in the myocardium of daunorubicin-treated animals were characterized by focal myocardial interstitial fibrosis of different intensity. The subsequent proliferation of the fibrotic tissue was marked by an increased content of both collagen types I and III, which resulted in their typical coexpression in the majority of bundles of fibers forming either smaller or larger scars. Biochemical analysis showed a significantly increased concentration of hydroxyproline, mainly in the pepsin-insoluble fraction of collagenous proteins, in the daunorubicin-treated group (1.42+/-0.12 mg/g) as compared with the control (1.03+/-0.04 mg/g) and dexrazoxane (1.07+/-0.07 mg/g) groups. Dexrazoxane co-administration remarkably reduced the cardiotoxic effects of daunorubicin to the extent comparable with the controls in all evaluated parameters. Using zymography, it was possible to detect only a gelatinolytic band corresponding to MMP-2 (MMP-9 activity was not detectable). However, no significant changes in MMP-2 activity were determined between individual groups. Immunohistochemical analysis revealed increased MMP-2 expression in both cardiomyocytes and fibroblasts. Thus, this study has revealed specific alterations in the collagen network in chronic anthracycline cardiotoxicity in relationship to the expression and activity of major MMPs.

Disseminated infection with Mycobacterium genavense in a grizzled giant squirrel (Ratufa macroura) associated with the isolation of an unknown Mycobacterium.

Disseminated infection with Mycobacterium genavense was diagnosed in an adult grizzled giant squirrel (Ratufa macroura). Microscopical examination showed granulomatous inflammation in the brain, kidneys, lungs and maxilla with intracellular acid-fast bacilli. M. genavense and a novel species of Mycobacterium (proposed name 'Mycobacterium lipsiensis') were identified.

Immunohistochemical and histochemical identification of proteins and carbohydrates in the equine endometrium Expression patterns for mares suffering from endometrosis.

Although alterations in patterns of protein secretion revealed in uterine flushings from mares suffering from endometrosis have been described, little is known about alterations at the cellular level. Hence, the aim of this study was to characterize deviations in patterns of uterine gland secretion patterns using endometrial biopsies, histochemical and newly established immunohistochemical methods. Forty-eight endometrial biopsies were obtained from mares suffering from various types of endometrosis (active and inactive, destructive and non-destructive) and degree (mild to severe) were analyzed for expression of the proteins uteroglobin, uteroferrin, calbindinD9k and uterocalin as representatives of endometrial proteins detectable by immunohistochemistry using polyclonal antibodies. Glycogen was identified using the PAS-reaction and mucopolysaccharides were stained with alcian blue. Uterine glandular epithelia within fibrotic foci mostly revealed a protein and carbohydrate pattern of expression which was independent of hormonal changes during the estrous cycle. In comparison to non-affected glands, most epithelial cells within periglandular fibrosis exhibited decreased immunostaining intensity for proteins, especially when there was destructive endometrosis. However, uteroferrin staining intensity was strong within areas of severe destructive endometrosis. Moreover, only few basal glandular epithelial cells, especially those in cystic glands, stained for mucopolysaccharides that are typically seen within the luminal epithelia. Usually a single fibrotic focus caused only slight alterations in glandular proteins and carbohydrate reaction patterns, so that only more severe endometrosis lead to deviations which were detectable in uterine flushings. The highly sensitive methods used in the present study allow studies of uterine secretion patterns in the context of routine assessment of endometrial biopsies.

Detection and characterization of chondroid metaplasia in canine atrioventricular valves.

The atrioventricular valves of 25 dogs of different breeds and age were examined grossly and microscopically following histochemical staining and immunohistochemical labelling for collagen types I, III and VI, and for fibronectin and laminin. Foci of cartilage were identified in the tricuspid septal leaflet within the fibrosa (n=21) or spongiosa (n=3). These were further characterized as either fibrocartilage, predominantly composed of collagens I and VI, or hyaline cartilage consisting of laminin and collagens III and VI. Eighteen of the dogs were of large breed and seven of small breed. Retrospective echocardiographic findings were available from five cases and in three of these a hyperechogenic structure was identified corresponding to the cartilage focus (0.1, 1.12 and 5.63 mm(2) in size). The clinical significance and mechanism of formation of these cartilaginous foci remain undetermined, although factors such as breed, size and concurrent chronic valvular disease may be significant.

Effects of autologous stem cells on immunohistochemical patterns and gene expression of metalloproteinases and their tissue inhibitors in doxorubicin cardiomyopathy in a rabbit model.

This study aims to investigate the expression of metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in chronic doxorubicin cardiomyopathy in a rabbit model and to evaluate the effects of bone marrow-derived mesenchymal stem cell (MSC) transplantation in this disease. Thirty-nine 3-month-old New Zealand rabbits were divided into 4 groups: group 1 (n = 9) was the untreated control. Groups 2-4 were treated with 6 weeks of doxorubicin (3 mg/kg). Group 2 (n = 6) received no further treatment. In group 3 (n = 9), animals were treated with culture medium (CM) alone. In group 4 (n = 15), autologous MSCs (1.5-2.0 x 10(6)/ml) were injected in the left ventricular (LV) wall. Hearts were stained with HE and picrosirius red. MMP-1, -2, -3 and -9 and TIMP-2 and -3 were detected immunohistochemically. The mRNA levels were determined by real-time polymerase chain reaction. The results confirmed that doxorubicin treatment resulted in minimal myocardial fibrosis and showed that expression of MMPs increased and TIMP-3 decreased. The injection procedure resulted in increased myocardial fibrosis in groups 3 and 4. After MSC injection, MMP-1, MMP-2, and TIMP-3 expression was higher than that in group 2. CM injection led to more fibrosis, elevated TIMP-3, but diminished MMP-1 and MMP-2 expression compared with MSC injection. The mRNA levels of MMPs and TIMPs were not significantly different among all groups. In conclusion, chronic doxorubicin cardiomyopathy was characterized by increased MMP and decreased TIMP-3 expression. MSCs injection into the LV resulted in marked differences of collagen content and MMP/TIMP expression in the whole heart, although significant numbers of living MSCs were not detected after 4 weeks.

[Efficacy and safety of various energy sources and application techniques for the surgical treatment of atrial fibrillation]. / Experimentelle Evaluierung verschiedener Energiequellen und Applikationsverfahren zur chirurgischen Therapie des Vorhofflimmerns.

We investigated efficacy and safety of different energy sources and application techniques for the treatment of atrial fibrillation in an experimental acute sheep model. In particular, we focused on thermal damage to the adjacent structures and tissues. We also attempted to evaluate the efficacy of different application techniques such as endocardial or epicardial approaches. Overall 64 young Merino sheep were examined. It could be shown that endocardial ablation with different energy sources on cardiopulmonary bypass consistently caused histomorphologically and electrophysiologically transmural lesions. Depending on the energy source, different amounts of endocardial damage were induced. Cryoapplication produces the smallest endocardial laceration without thrombus formation. Dry radiofrequency energy and microwave produced very wide and diffuse endocardial damage with carbonisation and disruption of the endothelium. Epicardial ablation on a beating heart (off-pump) with bipolar radiofrequency was consistently effective. Due to the energy flow between the two jaws of the bipolar clamp, no collateral damage was observed. All other energy sources were unable to produce transmural lesions epicardially (off-pump) because the nearby blood flow rewarmed or recooled the myocardium and caused the so called "heat sink phenomenon". Depending on the energy source, different histomorphological changes in the esophagus could be observed. Changes in intraluminal-measured esophageal temperatures were not observed during ablation.

Histomorphological and immunohistochemical characterization of equine granulosa cell tumours.

Benign (n=33) and malignant metastasizing (n=1) granulosa cell tumours (GCTs) from 34 mares aged 3-21 years, and normal (control) ovaries from nine mares aged 3-10 years, were examined histologically and immunohistochemically (for inhibin alpha, glutathione S-transferase alpha [GSTalpha], c-erbB-2 oncoprotein [cerb], cytokeratin, vimentin, desmin and alpha-actin), the results being related where appropriate to clinical signs and endocrinological data. Availability permitting, serum samples from GCT-affected mares before and several weeks after ovariectomy were examined for the following hormones: oestradiol, progesterone and testosterone (by radioimmunoassay); and inhibin B (by a cross-reactive ELISA). Histological examination revealed that the GCTs were predominantly well differentiated neoplasms. The metastasizing GCT differed immunohistochemically from the benign GCTs in respect of the expression patterns of vimentin, cerb and GSTalpha in the granulosa cells. A notable feature was the presence of Leydig-like cells in mares with stallion-like behaviour or elevated serum testosterone, or both. GSTalpha immunolabelling indicated that the Leydig-like cells were potential producers of steroid hormone. From the immunohistochemical and endocrinological findings it was concluded that GCTs produce abnormally high concentrations of inhibin, which reduce the release of follicle-stimulating hormone, leading to atrophy of the contralateral ovary-a finding in 27 of the mares.

Primary and secondary heart tumours in dogs and cats.

Primary and secondary neoplasms of the canine and feline heart are uncommon. During a 2-year period, 83 dogs suffering from primary cardiac (n=11), extracardiac benign (n=6) or malignant (n=66) tumours and 30 cats with primary cardiac (n=1) or extracardiac (n=29) malignant tumours were examined. Echocardiography revealed four cases of primary cardiac neoplasms in dogs, but secondary heart tumours were not detected. After necropsy, tissue samples from the heart and tumours were examined histologically and immunohistochemically. In dogs, primary neoplasms included seven haemangiosarcomas, two chemodectomas, one rhabdomyosarcoma, and one neurofibrosarcoma. In 24 of 66 dogs examined, metastases of extracardiac neoplasms were found in the heart (15 carcinomas, six malignant lymphomas, three haemangiosarcomas). In cats, one case of primary haemangiosarcoma of the pericardium and five cases of secondary cardiac tumours (two malignant lymphomas, three carcinomas) occurred. Cardiac neoplasms in cats were not identified clinically but were detected by detailed gross sectioning of the heart (n=2) or histopathological examinations (n=3). This study showed an unexpectedly high number (36%) of dogs with cardiac metastases.

Histopathological and immunohistochemical investigations of hepatic lesions associated with congenital portosystemic shunt in dogs.

Canine livers with congenital portosystemic shunt were investigated histopathologically and immunohistochemically before and 8-272 days after partial ligation of the shunt. Lesions included hypoplasia of portal veins, arteriolar and ductular proliferation, lymphangiectasis, mild to moderate fibrosis, fatty cysts, and mostly mild hepatocellular damage with frequent atrophy and steatosis, regardless of the location of the shunting vessel. Perisinusoidal hepatic stellate cells (HSCs) in normal canine liver expressed alpha-smooth muscle actin (alpha-SMA), but no desmin. In altered livers, however, raised expression of alpha-SMA was detected, together with expression of desmin, in varying numbers of HSCs. This was interpreted as a sign of cellular proliferation and transformation to myofibroblast-like cells. Additionally, there was an obvious perisinusoidal increase of several extracellular matrix components. Postoperative biopsy samples showed basically the same lesions as those of pre-operative samples, except that signs of resolution of hepatic changes were apparent.

Physiological and pathological expression of intermediate filaments in the equine endometrium.

The aim of this study was to investigate the expression of the intermediate filaments cytokeratin, vimentin and desmin in the equine endometrium by immunohistological techniques. For this purpose, endometrial biopsies of 151 mares were examined to determine physiological cycle patterns and changes resulting from endometriosis. During the physiological cycle epithelial cells and mesenchymal cells express cytokeratin and vimentin, respectively, whilst desmin and vimentin were coexpressed by the smooth muscle cells. Epithelial coexpression of cytokeratin and vimentin was seen in numerous fibrotic glands and in the uterine glands of three mares with pathologically inactive endometria. Three different staining patterns (basal, perinuclear, diffuse) of vimentin were associated with typical morphological alterations of the affected epithelia. In addition, in 14 cases a stromal coexpression of vimentin and desmin was found, indicating an atypical stromal differentiation in inactive endometria of older mares, barren for several years.

Epicardial treatment of atrial fibrillation using cryoablation in an acute off-pump sheep model.

BACKGROUND: The purpose of this study was to test the feasibility and effectiveness of cryoablation therapy (SurgiFrost trade mark CryoCath, Endocare Inc., Irvine, California, USA) for linear epicardial treatment of atrial fibrillation in an acute off-pump sheep model. METHODS: After thoracotomy, we performed epicardial cryoablation (2 min intervals at -160 degrees C) with pacing electrodes positioned at the left atrial appendage (LAA), the pulmonary veins (PVs), the right atrial appendage (RAA), and the vena cava cranialis (VCC) in 8 sheep. Circular epicardial ablations were performed with online temperature measurement in the ascending aorta and in the esophagus. The sheep were sacrificed two hours after ablation procedure, and heart, lungs, and esophagus were retrieved for histological examination. Out of all 8 sheep, histo-pathological analysis was performed on the RAA and VCC in 6 sheep and on the CAA and PV in all 8 sheep. RESULTS: Thin-walled structures such as PVs and VCC showed electrical isolation. No significant changes in temperature in the descending aorta and the esophagus were observed. There was evidence of extensive transmural alteration including vascular lesions, myocardial degeneration and necrosis as well as epi- and endocardial necrosis in the left atria in three of 8 cases, in the right atria in 5 of 6 cases, in the VCC in 6 of 6 cases, and in the PV in 5 of 8 cases. Mild lesions of the muscular layer of the esophagus were found in 7 of 8 cases. CONCLUSIONS: Epicardial cryoablation is not effective on thicker tissues like LAA and RAA due to the rewarming of the current blood flow. However, thin tissues like VCC and PV can be isolated. Further chronic studies are necessary to evaluate the potential for regeneration of adjacent structures.

[Tumors of the thyroid gland in dogs--a local characteristic in the area of Leipzig]. / Schilddrüsentumoren beim Hund--eine regionale Besonderheit im Raum Leipzig.

During 17 years (1985-2002) 4.072 necropsies in dogs were performed at the Institut für Veterinär-Pathologie of the University of Leipzig. 154 of them showed tumors of the thyroid. Retrospective classification of the neoplasia between 1992-2002 revealed 6 adenomas, 18 follicular, 33 solid-follicular and 21 solid carcinomas as well as one squamous cell carcinoma, one medullary (C-cell) carcinoma and one fibrosarcoma. During the time investigated, the number of thyroidal neoplasia out of all tumorous diseases in dogs decreased from 48% in 1986 to 3.8% in 2002. This phenomenon may be the result of an increased use of commercially produced animal food with supplementation of iodine. This may have led to the disappearance of the "typical" disease--thyroidal cancer--in dogs in this endemic area of iodine deficiency. The use of immunohistochemical markers shows that the expression pattern in neoplastic follicular areas mostly corresponds to the intact thyroidea. But in solid tumor regions the expression of thyroglobulin, cytokeratin 19 and neuron specific enolase (NSE) has diminished in most areas. Thyroid transcription factor 1 (TTF-1) is expressed in all carcinomas in variable intensity. Medullary carcinoma typically express calcitonin.

Development of a technique for transcervical collection of uterine tissue in bitches.

Transcervical collection of endometrial tissue specimens is a valuable and well established tool for the diagnosis of reproductive disorders in cows, mares and women, but it is not used currently in bitches. Endometrial biopsy samples were collected by transcervical cannulation from the cranial uterine body at defined stages of the oestrous cycle using biopsy forceps. In study 1, the histology of 45 biopsy specimens taken from 23 Beagle bitches were compared with larger tissue samples collected post mortem. For further evaluation of representative biopsy specimens, the expression of oestrogen and progesterone receptors was determined. Only 31.1% of the biopsy samples taken from bitches could be evaluated and they showed stroma, capillaries, luminal epithelium, glandular ducts and apical glands; however, basal glands and myometrium were not observed. Biopsy findings were in agreement with the diagnosis of the uterine specimens concerning endometrial differentiation, inflammatory and degenerative lesions. The expression of oestrogen and progesterone receptors was slightly lower in the biopsy samples. In study 2, a total of 49 serial biopsy samples were taken from 12 Beagle bitches. In eight bitches, the manipulation resulted in a haemomucometra. Treatment with PGF2 alpha and antibiotics led to a clinical cure in five of these dogs, two of which were mated successfully during the next oestrus. Three animals had to undergo ovariohysterectomy. Owing to the small proportion of biopsy specimens that was suitable for analysis and the high risk of biopsy-related endometritis, transcervical biopsy collection cannot be recommended as a routine technique in bitches.