Histologic features of mammary carcinomas in zoo felids treated with melengestrol acetate (MGA) contraceptives

Melengestrol acetate (MGA), a potent synthetic progestin, has been used as a contraceptive in zoo felids since 1975. Mammary gland carcinomas have been linked to MGA treatment in zoo felids, but the histologic features of these tumors and steroid receptor expression have not been described. Zoo felid mammary tumors were requested from participating zoos from 1986 through 1998, and 31 mammary carcinomas from 28 MGA-treated and 3 untreated felids were received. The carcinomas were evaluated on the basis of histologic pattern, tumor grade, and occurrence of metastasis; then features of the tumors were compared to determine if carcinomas in MGA-treated felids differed from those that occur spontaneously. Estrogen- and progesterone-receptor expression was evaluated in 17 of the 31 carcinomas. Of the 31 tumors, 22 (70.9%) had multiple histologic patterns, 29 (93.5%) were high grade, and 28 (90.3%) had metastasized. Within tumors, the tubulopapillary pattern was most common (87.1%, n = 27); solid (61.3%, n = 19), cribriform (38.7%, n = 12), and comedone (25.8%, n = 8) patterns were less common; and the mucinous (3.2%, n = 1) pattern was rare. Both MGA-treated and untreated zoo felids had similar patterns and grades of mammary gland cancer as well as prevalence of metastasis. These results indicate that mammary carcinomas in zoo felids are high grade with a predominant tubulopapillary pattern and aggressive behavior. Five of 17 carcinomas expressed progesterone receptors, and 1 of 17 expressed estrogen receptors. Although more zoo felids with cancer had been exposed to MGA in this study, mammary carcinomas were similar in appearance and behavior in untreated and MGA-treated zoo felids. The association of MGA with the development of malignant mammary gland tumors should be considered when using this contraceptive in zoo felids.     

Genital tract smooth muscle tumors are common in zoo felids but are not associated with melengestrol acetate contraceptive treatment

In a survey of gynecologic lesions in female zoo felids conducted to determine if the widely used progestin contraceptive melengestrol acetate (MGA) had adverse effects, numerous leiomyomas and leiomyosarcomas were detected. This current study aimed to characterize the morphologic features of these tumors, determine their prevalence, and assess if MGA was a risk factor for their genesis. Genital tracts from 219 zoo felids representing 23 species were evaluated, and leiomyomas were detected in 24% of the felids. Leiomyomas were often multiple and occurred in the myometrium, ovary, or adjacent broad ligament. The risk of developing leiomyomas increased with age, but MGA treatment or parity had no effect. Five other felids had leiomyosarcomas. Leiomyosarcomas were distinguished from poorly demarcated leiomyomas by the presence of local invasion, metastasis, and cellular atypia, but necrosis and mitotic rate were not distinguishing criteria. Four of five felids with leiomyosarcomas had been treated with MGA. These results indicate that leiomyomas are common spontaneous lesions in the genital tracts of zoo felids and their genesis is not linked to MGA exposure. Whether progression to malignancy is promoted by MGA warrants further investigation.     

Ability of intravaginal progesterone inserts and melengestrol acetate to induce estrous cycles in postpartum beef cows

Postpartum anestrous interval in beef cows is a major factor contributing to reproductive failure during a defined breeding season. Our objectives were to determine the ability of a controlled internal drug-releasing device (CIDR, 1.9 g of progesterone), a normal dose of melengestrol acetate (MGA, 0.5 mg x cow(-1) x d(-1)), or a high dose of MGA (4.0 mg x cow(-1) x d(-1)) to induce ovulation and to eliminate short estrous cycles. Multiparous beef cows (n = 100) were equally assigned to one of four treatments: CIDR, normal MGA, high MGA, or control by age, days postpartum, body condition, and body weight. All cows were fed carrier (0.9072 kg x cow(-1) x d(-1)) with (normal MGA, 0.55 mg/kg; high MGA, 4.41 mg/kg) or without MGA for 7 d (d -6 to 0). On d -6, CIDR were inserted and then removed on d 0. Estrous behavior was monitored continuously from d -6 until 29 using HeatWatch electronic mount detectors. Blood was collected on d -13, and three times weekly from d -6 to 29. Treatment influenced (P = 0.03) the percentage of cows that were detected in standing estrus. Beginning on d 2, more CIDR-treated cows had exhibited standing estrus compared with high MGA-treated or control cows, but CIDR- and normal MGA-treated cows did not differ. The percentage of CIDR-treated cows that had ovulated was greater (P < 0.05) than the percentage of normal MGA-treated, high MGA-treated, or control cows beginning on d 4. The percentage of cows that exhibited standing estrus before the first postpartum ovulation (CIDR = 65%, normal MGA = 57%, high MGA = 35%, control = 30%) did not differ (P = 0.09) among treatments. Luteal life span following the first ovulation postpartum and the percentage of cows with a normal luteal life span (i.e., progesterone > 1 ng/mL for > or = 10 d) was greater (P < 0.01) in CIDR-treated cows (14.0 +/- 0.8 d; 20/20, 100%) compared with normal MGA-treated (6.2 +/- 1.0 d; 3/13, 23%), high MGA-treated (9.6 +/- 1.0 d; 8/14, 57%), or control cows (6.1 +/- 0.9 d; 4/17, 24%), and greater (P < 0.03) in high MGA-treated cows than in normal MGA-treated or control cows. In the present study, treatment of early postpartum suckled beef cows with CIDR induced ovulation and initiated estrous cycles with a normal luteal life span in more cows than did treatment with MGA. Treatment with MGA (normal or high dose) did not induce ovulation earlier than in control cows, but a high dose of MGA increased the percentage of cows with normal luteal life spans following the first ovulation postpartum.     

Effects of melengestrol acetate on reproductive behavior and concentrations of LH and testosterone in bulls

We investigated the use of an orally active progestin (melengestrol acetate; MGA) to suppress reproductive activity in yearling beef bulls. Twenty-four crossbred bull calves were given a daily dose of 0, 0.5, 1.0, or 2.0 mg MGA for 99 d. Pulsatile patterns of LH and concentrations of testosterone and MGA were characterized on d 8, 36, 63, and 92 of the experiment. Numbers of aborted mounts, mounts with intromission, total mounts, and flehmen responses were assessed on d 15, 43, 71, and 99. Plasma concentrations of MGA were proportional to dose of MGA. Melengestrol acetate did not consistently affect mounting behavior in a dose-related manner, but, on d 99, number of total mounts for MGA-treated bulls was lower (P = 0.07) than that for control bulls. On d 15, MGA suppressed (P = 0.07) numbers of flehmen responses in a dose-dependent manner, but this effect was not sustained throughout the experiment. On d 8, concentrations of testosterone in control bulls were higher (P = 0.02) than in MGA-treated bulls, but this effect was not observed at other time periods. Overall, MGA caused slight decreases in mean concentrations of LH (P = 0.09) and LH pulse frequency (P = 0.06). Scrotal circumference was not affected by MGA. None of the behavioral traits was correlated with mean concentrations of LH or LH pulse frequency. Mounting activity was not correlated with testosterone concentrations, but number of flehmen responses was positively correlated with testosterone concentrations (P = 0.01). These results fail to support the hypothesis that progestins impair male sexual behavior or fertility in males.     

Evaluation of a fixed-time artificial insemination protocol for postpartum suckled beef cows

Treatment with melengestrol acetate (MGA), an oral progestin, prior to administration of gonadotropin-releasing hormone (GnRH) and prostaglandin F2alpha (PG) effectively synchronizes estrus and maintains high fertility in postpartum beef cows. The objective of this experiment was to determine whether treatment with MGA prior to a GnRH-PG-GnRH protocol would improve pregnancy rates resulting from fixed-time artificial insemination (AI). Multiparous crossbred beef cows at two University of Missouri-Columbia farms (n = 90 and n = 137) were assigned by age and days postpartum to one of two treatments. Cows were fed carrier (1.8 kg x animal(-1) x d(-1)) with or without MGA (0.278 mg x kg(-1)) for 14 d. All cows were administered GnRH (100 microg; intramuscularly) on d 12 after MGA or carrier withdrawal and 7 d before PG (25 mg; intramuscularly). All cows received a second injection of GnRH and AI 72 h after PG. Mean days postpartum for MGA and control cows at the initiation of treatment were 39.6 and 38.9 d for herd 1; and 51.9 and 50.9 d for herd 2, respectively (P > 0.70 within herds). Blood samples were collected from all cows at 10 and 1 d before the feeding of MGA or carrier began and at the times GnRH and PG were administered. Concentrations of progesterone in serum at the initiation of treatment were elevated (>1 ng/mL) in 0% of MGA and 7% of control cows in herd 1, and 54% of MGA and 49% of control cows in herd 2 (P > 0.05 within herds). Pregnancy rates to fixed-time AI were determined by transrectal ultrasonography 50 d after AI. Pregnancy rates in herd 1 were 58% (26/45) and 51% (23/45) for MGA-treated and control cows, respectively (P = 0.52), and 63% (44/70) and 45% (30/67) for MGA-treated and control cows in herd 2, respectively (P = 0.03). Differences in pregnancy rates to fixed-time AI were significant (P = 0.04) when data from the two herds were combined (with MGA = 70/115 [61%]; control = 53/112 [47%]). There was no difference (P > 0.20) in final pregnancy rates (timed AI plus 45 d exposure to bulls) between treatments, within herds, or when herds were combined. In summary, pregnancy rates resulting from fixed-time AI may be improved with treatment of MGA prior to a GnRH-PG-GnRH protocol.     

Effect of zeranol or melengestrol acetate (MGA) on testicular and antler development and aggression in farmed fallow bucks

Fifteen yearling fallow bucks were randomly assigned by BW to one of three treatment groups: control (C; n = 5), melengestrol acetate (MGA; n = 5), and zeranol (Z; n = 5), to evaluate effects on testicular development, aggressive behavior, antler growth, sexual activity, ADG, and BW. Zeranol-treated bucks received zeranol ear implants (36 mg) at 90-d intervals, and MGA-treated bucks received MGA in the ration (100 microg x animal(-1) x d(-1)). Bucks grazed ryegrass/Coastal bermudagrass pasture and were supplemented with 3:1 corn/soybean meal at 0.45 kg x animal(-1) x d(-1). Body weights, body condition scores (BCS), blood samples, and testis measurements were obtained at d 0 and at 14-d intervals for 229 d. As bucks reached hard antler (7/15 to 8/25), antlers were harvested and weighed, and ejaculates were collected at 14-d intervals. Aggression was evaluated using 10-min video sessions scoring body blows, avoidance, head pushes, and head bunts. Scrotal circumference (SC) and paired testis volume were affected by a day x treatment interaction (P < 0.01); testes of zeranol-treated bucks were smaller than those of control or MGA-treated bucks. First sperm in the ejaculate tended to be delayed (P < 0.10) in zeranol-treated bucks compared with control and MGA-treated bucks. Melengestrol acetate-treated bucks had a maximum sperm concentration in the ejaculate that was three times (P < 0.05) that of control bucks and nine times (P < 0.05) that of zeranol-treated bucks. Antler weight was the least (P < 0.01) for bucks receiving zeranol and greatest (P < 0.10) for MGA-treated bucks; intermediate values were recorded for the control bucks. Aggressive behavior was delayed (P < 0.05) for zeranol-treated bucks until treatment effects were overcome. Melengestrol acetate-treated bucks had decreased (P < 0.01) aggressive behavior compared with control bucks. Melengestrol acetate-treated bucks had increased (P < 0.05) serum testosterone concentrations compared with control and zeranol-treated bucks. Human chorionic gonadotropin-stimulated peak serum testosterone concentrations for zeranol-treated bucks were delayed (P < 0.01) compared with control and MGA-treated bucks. Although zeranol-treated bucks overcame treatment effects, they were never able to reach testicular measurements or sperm concentrations equal to those of the control or MGA-treated bucks. Zeranol and MGA treatments may have both positive and negative effects that can be utilized when producing slaughter bucks.     

Endometrial hyperplasia,polyps, and adenomyosis associated with unopposed estrogen in rhesus monkeys (Macaca mulatta)

The purpose of this study was to evaluate the effects of estrogen and progesterone on the vaginal mucosa and their role in vaginal transmission of simian immunodeficiency virus. Incidentally, endometrial hyperplasia was observed in estrogen-treated monkeys at necropsy. Six adult female rhesus monkeys (Macaca mulatta) were ovariectomized and 120 days later received two subcutaneous implants, each containing 200 mg estradiol. The animals were sacrificed 17-27 months later and the uterus examined at necropsy. All the monkeys had simple endometrial hyperplasia, some with polyps or adenomyosis, at the time of necropsy. The severity of the changes correlated with the time between implantation and necropsy. The lesions were similar to endometrial hyperplasia caused by unopposed estrogen in women, but occurred over a time period that is suitable for experimental manipulation. Rhesus monkeys could be used as a model to test the safety of various combinations of sex steroids for the prevention of postmenopausal symptoms in women.     

Effect of melengestrol acetate on development of 3-methylindole-induced pulmonary edema and emphysema in sheep.

The involvement of melengestrol acetate (MGA) in susceptibility to developing pulmonary edema and emphysema following oral administration of 3-methylindole (3MI) was investigated using 10 Suffolk ewes receiving 0 or 0.15 mg of MGA daily (n = 5). Blood, urine and ruminal fluid were collected immediately prior to 3MI dosing (0.2 g/kg BW) and 1, 2, 3, 4, 5, 6, 12 and 24 h (blood); 3, 6, 9, 12 and 15 h (urine) and 1, 2, 3 and 12 h (ruminal fluid) afterward. Ewes receiving MGA experienced earlier (P < 0.05) onset of respiratory distress than the control ewes (2.5 vs 4 h), and upon euthanasia at 96 h, their lung weight relative to body weight tended (P < 0.10) to be lower. Ruminal 3MI concentrations did not differ between treatments (P > 0.05). Ewes receiving MGA had higher (P < 0.05) concentrations of 3MI metabolites in plasma prior to dosing than did control ewes, and these values tended to remain higher throughout the sampling period. Immunoreactivity assays indicated more pneumotoxin present in the lungs of MGA-treated ewes than controls. Lung damage was apparently more acute and accelerated in the MGA-treated ewes than in the controls. Urinary 3MI mercapturate concentrations differed (control > MGA-treated, P < 0.05) at 9, 12, and 15 h, but this difference was not apparent when urinary production (as estimated by creatinine concentration) was considered. The implications of these findings for MGA-treated feedlot heifers are currently under investigation.     

Effects of porcine zona pellucida immunocontraceptives in zoo felids.

Methods of contraception are necessary for management of zoo felids; however, the most commonly used contraceptive (melengestrol acetate implant) is associated with serious adverse reactions with long-term use. Porcine zona pellucida (pZP) vaccines are promising as contraceptives, but their safety in zoo felids has not been tested. pZP vaccine was administered to 27 female felids representing 10 species, including African lion (Panthera leo), Asian leopard (P. pardus), jaguar (P. onca), tiger (P. tigris), snow leopard (P. uncia), cougar (Felis concolor), Siberian lynx (F. lynx), Canada lynx (F. canadensis), serval (F. serval), and bobcat (F. rufus), in 15 facilities. Over 6 wk, each animal received three i.m. injections of 65 microg pZP with Freund's complete adjuvant (FCA), Freund's incomplete adjuvant, or carbopol as the adjuvant. Behavioral signs of estrus were seen in 14 of the vaccinated felids. An unacceptably high incidence of adverse reactions was seen including injection site swelling, lameness, limb swelling, or abscessation (or all) in five felids after injection with FCA as the initial adjuvant. Adverse behavioral signs, including increased irritability and aggression, were seen in four felids. Six of the felids were assayed for antibodies against pZP during the 12 mo after vaccination; all showed antibody production. Antibody levels appeared to peak 1-4 mo after vaccination began, although elevated antibody levels persisted in two animals for > 12 mo after the first injection. All vaccinated felids were ovariohysterectomized 3-13 mo after vaccination. Folliculogenesis was present in all treated animals, and there was no histopathologic evidence of inflammatory damage to ovaries. Contraceptive efficacy was not specifically evaluated in this study; however, two of the three felids housed with an intact male became pregnant during the study, one of which gave birth to healthy cubs.     

Cystic endometrial hyperplasia in elephants

Most captive female elephants are nulliparous and aged and many have endometrial disease, factors that may hinder fertility. This study characterized the pathologic features and demographic distribution of endometrial lesions from 27 captive Asian (Elephas maximus) and 13 African elephants (Loxodonta africanus), 12- to 57-years of age. The principal lesion was marked cystic and polypoid endometrial hyperplasia (CEH), present in 67% of Asian and 15% of African elephants ranging from 26 to 57 years. The lower prevalence in African elephants likely reflects their younger age range in this study. Fourteen of 15 affected elephants with breeding information were nulliparous. These results suggest that CEH and polyps are common in aged nulliparous elephants, and the severity of these lesions may impair fertility. These findings will be useful in the interpretation of ultrasonographic findings during reproductive examinations of potential breeding cows. Also, breeding programs should focus on younger animals.     

Control of the bovine estrous cycle with melengestrol acetate (MGA): a review

Expanded use of artificial insemination in the beef cattle industry depends on successful application of treatments designed to synchronize estrus. Regulation of estrous cycles is associated with control of the corpus luteum (CL), whose life span and secretory activity are subject to trophic and lytic mechanisms. The advantages of melengestrol acetate (MGA) in estrous synchronization incorporate ease of administration, lower cost relative to other estrous synchronization products, and potential for use to induce estrus in prepubertal heifers. Treatments first designed to synchronize estrous cycles of normally cycling heifers by feeding MGA were imposed daily for 14 to 18 d at levels of .5 to 1 mg. The minimal daily effective dose required to inhibit ovulation was .42 mg. Longer feeding periods of MGA were associated with low fertility at the first synchronized estrus, but at the second estrus, conception was normal. Low fertility at the synchronized estrus resulted in development of alternative treatment practices, which combined feeding of MGA with injections or implants of estradiol-17 beta, estradiol cypionate, luteinizing hormone, human chorionic gonadotropin, pregnant mare serum gonadotropin, or oxytocin. Estrus was synchronized after MGA and estradiol-17 beta or estradiol cypionate treatments, but fertility was low. Short-term feeding of MGA (5 to 7 d) combined with prostaglandin F2 alpha or its analogs (PGF) on the last day of MGA reduced fertility at the synchronized estrus. The reduced conception at first service occurred in animals that began treatment after d 12 of the estrous cycle. However, feeding MGA for 14 d and then injecting PGF 17 d later avoided problems with reduced conception. Fertility of animals after this treatment was similar to that of contemporaries synchronized with Syncro-Mate-B. However, the length of the treatment period creates a need for increased management and may extend management beyond practical limits. Further research is warranted to address problems associated with reduced fertility after short-term treatment with MGA.     

Do free-ranging common brushtail possums (Trichosurus vulpecula) play a role in the transmission of Toxoplasma gondii within a zoo environment?

To investigate the possible role of common brushtail possums (Trichosurus vulpecula) in the transmission of Toxoplasma gondii within a zoo environment, a serological survey of a free-ranging population resident within Taronga Zoo, Sydney, Australia was undertaken using the modified agglutination test (MAT). For comparison, the seroprevalence of T. gondii antibodies was also assessed in a possum population inhabiting a felid-free, non-urban woodland habitat. Six of 126 possums (4.8%) from the zoo population had antibodies to T. gondii with a MAT titre of 25 or higher, while in contrast, all of the 17 possums from woodland were seronegative. These observations suggest that possums were at a higher risk of exposure to the parasite as a consequence of co-existing with domestic, stray and captive felids associated with urbanisation. Screening of captive felids at the zoo indicated 16 of 23 individuals (67%) and all 6 species were seropositive for T. gondii, implicating them as a possible source of the parasite within the zoo setting. In addition captive, non-felid carnivores including the chimpanzee (Pan troglodytes), saltwater crocodile (Crocodylus porosus), dingo (Canis lupis) and leopard seal (Hydrurga leptonyx) were tested for the presence of T. gondii antibodies as these species predate and are a leading cause of death amongst zoo possums. In total, 5 of 23 individuals (22%) were seropositive, representing 2 of the 4 carnivorous species; the dingo and chimpanzee. These data suggest that carnivory was not a highly efficient pathway for the transmission of T. gondii and the free-ranging possum population posed minimal threat to the health of zoo animals.     

Melengestrol acetate blocks the preovulatory surge of luteinizing hormone,the expression of behavioral estrus,and ovulation in beef heifers

We tested the hypothesis that melengestrol acetate (MGA), an orally active progestin, blocks estrus and the preovulatory surge of luteinizing hormone (LH) in beef heifers. Cycling yearling Angus heifers were divided randomly into two groups: MGA-treated (n = 6) and control (n = 5). All heifers received injections of prostaglandin F2alpha (PGF) on d -25, -11, and 0 to synchronize estrus. Following the last PGF injection on d 0, heifers were fed either 0.5 mg MGA in a carrier or the MGA carrier each day for 8 d. At 4-h intervals on d 1 through 6, all heifers were observed for expression of estrous behavior, and blood samples were collected and assayed for LH. Daily blood samples were collected at 0800 on d 1 through 10 and assayed for circulating progesterone concentrations. All control heifers exhibited estrus and a preovulatory surge of LH. In each case, this was followed by increases in circulating concentrations of progesterone indicative of ovulation and normal luteal function. In contrast, none of the MGA-treated heifers exhibited estrus, LH surges, or evidence of ovulation. The results of this experiment show that MGA prevents ovulation in cattle by inhibiting the preovulatory surge of LH.     

Uterine adenomyosis in an orang-utan (Pongo abelii/pygmaeus)

A 48-year-old, multiparous, female hybrid orang-utan ( Pongo abelii/pygmaeus ) was investigated after a 3-year history of irregular and excessively heavy menstrual bleeding. Opportunistic pelvic examinations over a 2.5-year period were non-diagnostic. Medical therapy was not effective. A subtotal hysterectomy with bilateral salpingo-ovariectomy was performed. A pedunculated mass spanning 90% of the uterine lumen was seen grossly, and histopathology confirmed uterine adenomyosis. Adenomyosis is defined as the ectopic occurrence or diffuse implantation of endometrial tissue, including glands and stroma, into the myometrium. It is common in older, usually premenopausal, multiparous women and is frequently associated with other uterine pathology, including endometrial hyperplasia and leiomyomas. The most common clinical signs are dysmenorrhoea and heavy menstrual bleeding; however, up to 35% of women are asymptomatic. Diagnosis is difficult and requires myometrial sampling and an experienced pathologist. A hysterectomy in this case was diagnostic and curative. There have been few reports of uterine adenomyosis in non-human primates and none reported in an orang-utan. Uterine adenomyosis should be considered in the differential diagnosis in any multiparous, aged, non-human female primate with irregular and excessively heavy menstrual bleeding, and hysterectomy with bilateral salpingo-ovariectomy is recommended as a diagnostic and therapeutic solution.     

Hermaphroditism in 3 chimeric mice

Hermaphroditism was diagnosed in three, 6-month-old, male, chimeric mice generated by microinjection of 129/Ola XY recombinant embryonic stem cells into unsexed C57BL/6 blastocysts. Grossly, mice Nos. 1 and 2 had perigenital masses and hydrometra. All mice had unilateral ovaries and cystic endometrial hyperplasia. Mice Nos. 1 and 3 also had contralateral testes and epididymides. Histologically, mice Nos. 1 and 3 were true hermaphrodites with unilateral ovotestes, while mouse No. 2 was a pseudohermaphrodite with ovarian tissue only. The presence of a uterus with cystic endometrial hyperplasia in these mice resembles XY pseudohermaphroditism in miniature schnauzers. The mice were determined to be 95 to 100% chimeric via haircoat color; however, the presence of both male and female sex organs in these phenotypically male mice suggests otherwise. Published reports note incidences for sex chimeras and hermaphroditism in genetically engineered mice of 50% and 20%, respectively. Hermaphroditism is expected to increase as the numbers of chimeric mice rise with technical advances in genetic engineering.     

Endometrial polyps in 2 African pygmy hedgehogs

Reports of spontaneously occurring endometrial polyps in animals are rare and have only involved a few species. This report is intended to advise veterinarians that older African pygmy hedgehogs may develop endometrial polyps and that these lesions can be a cause of bloody vaginal discharge, sometimes interpreted as hematuria.     

Spontaneous proliferative lesions and tumors of the uterus of captive African hedgehogs (Atelerix albiventris).

Fifteen captive female African hedgehogs (Atelerix albiventris), 3- to 5-yr-old, were diagnosed with proliferative uterine lesions (n = 28). Lesions were associated with vaginal bleeding in all cases, hematuria in 11 of 13 cases, and weight loss in 7 of 12 cases. Lesions were multiple in eight cases and single in seven cases. The lesions identified were 13 adenosarcomas, 7 endometrial stromal sarcomas, 6 endometrial polyps, 1 adenoleiomyosarcoma, and 1 adenoleiomyoma. In one animal with adenosarcoma, peritoneal seeding was detected at the time of hysterectomy. Mean survival time was 303 days (n = 10). Ovariohysterectomy allows prolonged survival of hedgehogs with uterine tumors.     

Lectin‐binding Sites on the Normal and Pathologic Uterus of Sows

The lectin‐binding pattern was compared in the normal and pathological uterus of sows during the ovarian cycle. The following biotinylated lectins were used: Con A, DBA, SBA, PNA, RCA‐I, UEA‐I and WGA. Glycoconjugate labelling showed differences between phases of ovarian cycle and presence of morphologic lesions. Cystic endometrial hyperplasia increased the RCA‐I reaction in the apical region of the glandular epithelium. There was higher intensity of labelling of WGA in the glandular epithelium in uteri with endometritis. In addition, increased Con A binding in the glandular epithelium and mild reduction of UEA‐I reactivity in the glycocalyx of the glandular epithelium were detected in the cases of endometritis. The results of this study show that morphologic alterations modify the sugar pattern in the porcine uterus. These modifications in glycoconjugates may be one of the reasons for decreased fertility in sows.     

Bile duct dysplasia and congenital hepatic fibrosis associated with polycystic kidney (Caroli syndrome) in a rat

Hepatic fibrosis with bile duct ectasia and hyperplasia associated with polycystic kidney disease, analogous to Caroli syndrome in humans, was observed in a rat used as a control in a subchronic toxicity study. Light microscopy of liver sections showed multiple cystic and segmental saccular dilatations and hyperplasia of the intrahepatic bile ducts associated with overgrowth of portal connective tissue; the kidneys had diffuse cystic dilatation of cortical renal tubules. The lesions resembled those of human cases of the fibropolycystic disease termed as Caroli syndrome, which is thought to be the result of a pathologic developmental process known as ductal plate malformation. Recently, an animal model of Caroli syndrome has been described in mutant rats from a colony that constantly showed renal and hepatic cysts and an autosomal recessive mode of inheritance. The finding in our case of identical hepatorenal lesions suggests that the same mutation has occurred incidentally in a standard colony.     

Unilateral uterine torsion secondary to an inflammatory endometrial polyp in the bitch

A 9-year-old bitch was presented because of lethargy and abdominal distension. Abdominal ultrasound revealed an enlarged, fluid-filled uterus and associated mass. Subsequent exploratory laparotomy revealed unilateral uterine torsion involving the mass. Recovery following ovariohysterectomy was uneventful and the histopathological diagnosis was of a benign endometrial inflammatory polyp. Reports of uterine torsion in the English-language literature are reviewed to identify factors associated with the incidence of uterine torsion. The aetiology of the cystic endometrial hyperplasia/pyometra complex and its possible role in the development of inflammatory polypoid lesions in the bitch is also discussed.