Effect of Ovariohysterectomy at the Time of Tumor Removal in Dogs with Mammary Carcinomas: A Randomized Controlled Trial.

BACKGROUND: Ovarian hormones play crucial roles in mammary carcinogenesis. However, whether ovarian ablation by ovariohysterectomy (OHE) improves the prognosis in dogs with mammary carcinomas is unclear. OBJECTIVES: Determine if OHE at the time of mastectomy improves the prognosis in dogs with mammary carcinomas and evaluate if hormonal factors influence the effect of OHE. ANIMALS: Sixty intact dogs with mammary carcinomas. METHODS: Dogs were randomly assigned in a 1:1 ratio to undergo OHE (n = 31) or not (n = 29) at the time of tumor removal. Peri-surgical serum estradiol (E2) and progesterone concentrations were measured, tumor diagnosis was confirmed histologically, and tumor estrogen and progesterone receptor status was immunohistochemically determined. The dogs were monitored for recurrence and metastases every 3-4 months for at least 2 years. Uni- and multivariable survival analyses were performed with relapse and all-cause death as endpoints in addition to univariable subgroup analyses. RESULTS: Overall, OHE did not significantly decrease hazard of relapse (hazard ratio [HR], 0.64; P = .18) or all-cause death (HR, 0.87; P = .64) in univariable analyses. In multivariable analysis OHE did not significantly influence the hazard of relapse (HR, 0.54; P = .12), but an interaction effect was identified between ER status and E2 (P = .037). Subgroup analysis identified decreased hazard of relapse in the OHE group compared to the non-OHE group in the subsets of dogs with increased E2 (HR, 0.22; P = .012) or grade 2 tumors (HR, 0.26; P = .02). CONCLUSION: Dogs with grade 2, ER-positive tumors, or with increased peri-surgical serum E2 concentration represent a subset of dogs with mammary carcinomas likely to benefit from OHE.

Effect of ovariohysterectomy at the time of tumor removal in dogs with benign mammary tumors and hyperplastic lesions: a randomized controlled clinical trial.

BACKGROUND: Nonmalignant mammary tumors (NMT) are common in intact female dogs. Little is known about the clinical significance of these tumors, and the effect of ovariohysterectomy (OHE) on their development. HYPOTHESIS: Ovarian hormone ablation through OHE decreases the risk of new tumors and thereby improves long-term prognosis for dogs with NMT. ANIMALS: Eighty-four sexually intact bitches with NMT. METHODS: Dogs were allocated to undergo OHE (n = 42) or not (n = 42) at the time of NMT removal in a randomized clinical trial. Tumor diagnosis was confirmed histologically in all subjects. Information about new tumor development was collected via follow-up phone calls and recheck examinations. Separate survival analyses were performed with the endpoints new tumor development and death. Cause of death was classified as related or unrelated to mammary tumor. In addition to OHE status, the influence of age, body weight, breed, tumor size, tumor number, tumor duration, type of surgery, and tumor histology was investigated. RESULTS: New mammary tumor(s) developed in 27 of 42 (64%) intact dogs and 15 of 42 (36%) ovariohysterectomized dogs (hazard ratio 0.47, P = .022). Nine of the 42 dogs (21%) which developed new tumors were euthanized because of mammary tumor. Survival was not significantly different between the 2 treatment groups. In the intact group, nine dogs subsequently developed ovarian-uterine diseases. CONCLUSION: Ovariohysterectomy performed at the time of mammary tumor excision reduced the risk of new tumors by about 50% among dogs with NMT. Survival was not significantly affected. Adjuvant OHE should be considered in adult dogs with mammary tumors.

Canine mammary gland tumours; a histological continuum from benign to malignant; clinical and histopathological evidence.

This study describes the clinical and histopathological findings in dogs with mammary gland tumours, and compares the histopathological and clinical evidence consistent with progression from benign to malignant to human breast cancer epidemiology. Clinical and histopathological data on 90 female dogs with 236 tumours was included. Dogs with malignant tumours were significantly older than dogs with benign tumours (9.5 versus 8.5 years), P = 0.009. Malignant tumours were significantly larger than benign tumours (4.7 versus 2.1 cm), P = 0.0002. Sixty-six percent had more than one tumour, and evidence of histological progression was noted with increasing tumour size. Dogs with malignant tumours were significantly more likely to develop new primary tumours than dogs with benign tumours, P = 0.015. These findings suggest that canine mammary tumours progress from benign to malignant; malignant tumours may be the end stage of a histological continuum with clinical and histopathological similarities to human breast carcinogenesis.

Polyneuropathy associated with forage sources in Norwegian horses.

BACKGROUND: Cases of hindlimb digital extensor weakness of unknown etiology have been observed in Norway since 1995. HYPOTHESIS: We hypothesized that the observed bilateral extensor weakness was attributable to neuropathy of the distal nerves and that this was related to environmental factors, possibly dietary. ANIMALS: Seventy-five horses with digital extensor weakness occurring from 1995 to 2004 are described. METHODS: Eleven horses were examined at The Norwegian School of Veterinary Science, and the medical records of 64 horses seen in ambulatory practice were reviewed. RESULTS: There was no apparent sex, age, or breed predilection, but the majority were horses kept for pleasure or breeding purposes. Clinical signs varied from intermittent knuckling of the hindlimbs to paraplegia. Some horses showed no or only slow progression of signs, whereas others developed severe signs within hours. No other neurologic deficits were detected in any of the horses. Epidemiologic data and laboratory results were not supportive of an infectious etiology. The only common factor for all affected horses seemed to be feeding big bale silage or, occasionally, hay of poor microbiologic quality. Forty of the 75 horses were euthanized. Histopathologic examination of peripheral nervous tissue was performed in 22 horses, all of which had neuronal fiber degeneration. The majority of horses with mild signs recovered after 5-6 months of rest. CONCLUSIONS AND CLINICAL IMPORTANCE: Clinical signs correlated with polyneuropathy involving sciatic nerves.

The effect of parentage on the prevalence, severity and location of lesions of osteochondrosis in swine.

The aims of this study were to determine the effects of parentage and gender on the prevalence, severity and location of lesions of osteochondrosis manifesta (OCM) and osteochondrosis dissecans (OCD) in offspring from different Norwegian Landrace boars and to examine the relationships between lesion characteristics and selected growth parameters. Fifteen sires were selected based on their high breeding value for osteochondrosis. Seven locations in the distal humerus and the distal femur from 1680 offspring of these animals were evaluated for severity of OCM and presence of OCD by gross examination of serially sectioned humeri and femora. Osteochondrosis manifesta was most prevalent in the trochlea of humerus, the sagittal ridge of humerus, the medial condyle of femur and the medial sulcus obliquus of femur. The severity of the lesions and the prevalence of OCD were highest in the trochlea and the sagittal ridge of humerus. Castrates had significantly higher OCM scores than sows. There were significant effects of both sire and dam on the OCM scores of the offspring in most locations; however, growth rate and weight at slaughter did not influence the OCM score.

Vascularisation and osteochondrosis of the epiphyseal growth cartilage of the distal femur in pigs--development with age, growth rate, weight and joint shape.

Until recently, the cartilage canals of the epiphyseal growth cartilage have not been associated with any specific disease. However, data support the hypothesis that osteochondrosis could be related to inadequate blood supply from vessels in these channels. We have done a study to investigate the relationship between the regression of cartilage canals and the formation of osteochondrosis latens in the epiphyseal growth cartilage of the distal femur in pigs, and the relationship between these events and age, growth rate, weight and femoral shape of the individual animals. This involved, in part, a comprehensive study of the distribution and pattern of regression of the cartilage canals. We found that the regression is a highly predictable process that follows an age-dependent pattern. However, we failed to prove any association between overall vascular regression and osteochondrosis, between vascular regression and weight, growth rate or femoral shape or between osteochondrosis and weight, growth rate or femoral shape. This may indicate that osteochondrosis latens is not caused by a general failure of vascular supply or general factors such as growth rate, but rather a consequence of local conditions affecting a limited number of vessels. A factor fitting this description is local compression.

Accessory ossification centres associated with osteochondral fragments in the extremities of horses.

Fifty-six tarsocrural joints and 94 metatarsophalangeal joints were examined, at necropsy, from horses aged < or = 2 years. Osteochondral fragments at the cranial aspect of the intermediate ridge of the distal part of the tibia were seen in six horses, and at the proximoplantar aspect of the proximal phalanx in seven horses. Defects in the proximoplantar aspect of the proximal phalanx without osteochondral fragments were seen in a further two horses. Inflammatory and degenerative changes were not observed in any of the joints examined. From the incidence and natural course of these fragments, and from the radiological and microscopical findings, accessory ossification centres would seem the most probable cause of the osteochondral fragments at the cranial aspect of the intermediate ridge of the distal part of the tibia and at the proximoplantar aspect of the proximal phalanx.

Acute post-treatment enterocolitis in 13 horses treated in a Norwegian surgical ward.

Case histories, results of laboratory analyses, treatment regimens and outcome are described for 13 horses that developed acute enterocolitis after various surgical treatments. Twelve of the 13 horses had been cast in lateral recumbency, and 10 of those 12 had received general anesthesia. Eleven horses had been treated with antimicrobial drugs. Most horses (11) developed diarrhea 2 days after initiation of treatment, with a variation from 1 to 5 days. The most apparent symptoms were fever, up to 40.5 degrees C, elevated heart rate, discoloration of mucous membranes, and diarrhea. Dehydration, acidosis and leukopenia were marked at the time clinical signs occurred. Packed cell volume and total serum protein values were elevated. Therapy was directed toward replacement of fluid losses, restoration of acid-base balance, and counteraction of inflammation. Seven horses (54%) died or were euthanized. At necropsy, pathological changes showed large variations between individuals. Salmonella spp. were not isolated from any of the horses, and no common causative agent was identified. Preventive efforts to avoid post-treatment enterocolitis have been taken with regard to preoperative routines, premedication and anesthesia, with apparent success.

Unstable stifles without clinical or radiographic osteoarthritis in young goats: an experimental study.

Thirteen young, castrated male goats had instability of one stifle (knee joint) created by surgical transection of the cranial cruciate ligament, but did not develop any signs of osteoarthritis (OA) in treated joints when confined in limited space for 8 months. At the end of the experiment, the instability in the stifles had not improved, the joints were normal at radiographic examination, there were no signs of inflammation in the synovial membrane or joint capsule, and fibrosis in these tissues was not evident. The articular cartilage was normal both visually and histologically. This may indicate that the young age of the goats and the restricted physical activity on soft floor had prevented the expected development of OA in the experimentally operated joints. Synovial fluid volumes and proteoglycan concentration were measured in the treated and control joints in 6 of the goats. There seemed to be increased quantity of the proteoglycan aggrecan in the synovial fluid from the treated joints compared to the contralateral joints throughout the course of this study. It was concluded that the turnover of aggrecan in the articular cartilage of the treated joints may have been increased.

Degenerative changes in the temporomandibular joint after diagnostic arthroscopy. An experimental study in goats.

Arthroscopic procedures for diagnosis and treatment of temporomandibular joint (TMJ) diseases are widely used. Few adverse effects of the procedures have been reported. In this in vivo study, diagnostic arthroscopy was performed in the left TMJ of seven castrated male goats, the right TMJ serving as a control. The goats were killed 1, 2, and 3 months after the arthroscopy. Macroscopic and microscopic examination revealed no apparent pathologic changes in two animals, minor changes in two, and severe degenerative changes in three. This study indicates that arthroscopic intervention in the TMJ may cause irreversible changes in the articular tissues.

Regional enteritis in lambs.

Thirty-two lambs with regional enteritis were examined. Eighteen were received alive and examined clinically, while the remaining were dead on arrival. One of the sick lambs recovered without treatment. Occurrence and epidemiology, clinical signs, clinical pathology, necropsy findings, light microscopy, immunoperoxidase studies, scanning electron microscopy and transmission electron microscopy are reported. The disease was characterised by stretching of the fore- and hindlimbs, ill thrift, intermittent diarrhoea, leucocytosis, thickened ileal wall and hyperplasia of the ileal mucosa. None of the methods applied revealed any causal agents. Possible aetiological factors are discussed.

Corynebacterium pseudotuberculosis infection in goats. VIII. The effect of vaccination against experimental infection.

The effect of an inactivated vaccine against C. pseudotuberculosis infection was tested on castrated male kids from a herd free from caseous lymphadenitis. The animals were divided into 3 groups with 8 animals in each. Group 1 was immunized with crude filtrated C. pseudotuberculosis toxoid and whole killed organisms, while Group 2 in addition was given levamisole. The kids were vaccinated twice at an interval of 4 weeks. Group 3 consisted of unvaccinated animals. All groups were challenged subcutaneously with live bacteria 4 weeks after the last vaccination. Unvaccinated animals showed the most severe course of illness after challenge. Development of abscesses in the regional lymph nodes (Inn. subiliaci) was significantly more common in unvaccinated than in vaccinated kids at necropsy 2 months after challenge. There was, however, no such difference between the vaccinated groups, and there was no difference between any of the groups as regards abscess formation at the inoculation site. In each of the 2 vaccinated groups, there was a titre rise following vaccination in the hemolysis inhibition test, whereas no such rise was seen in the bacterial agglutination test. The titre values in both tests increased significantly after challenge in all the groups, the increase being most rapid in the vaccinated animals. The present investigation indicates that development of caseous lesions in lymph nodes in goats, following subcutaneous inoculation with C. pseudotuberculosis, can be reduced by an inactivated vaccine containing whole organisms and crude toxin.

Swine dysentery: the influence of dietary vitamin E and selenium on the clinical and pathological effects of Treponema hyodysenteriae infection in pigs.

Twenty-four conventionally reared pigs were divided into four equal groups and fed a basic ration deficient in vitamin E and selenium. One group was given a supplement of vitamin E and selenium. One group was given a supplement of vitamin E, another received selenium and a third received both nutrients. No supplement was given to the control group. After the pigs had been fed the different diets for 59 days they were inoculated with a pure culture of Treponema hyodysenteriae They were subsequently observed for 22 days. The inoculation resulted in outbreaks of swine dysentery in all groups. The results indicated that the administration of vitamin E supplement alone to the pigs reduced the clinical effects of T hyodysenteriae only to a minor degree. On the other hand, supplementation with selenium, either alone or with vitamin E, had a more positive effect which was most clearly illustrated by a greater weight gain during the postinoculation period.