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1.
Melengestrol acetate (MGA) contraceptives are widely used in zoo felids to regulate fertility and may have deleterious effects on endometrial health. To determine whether MGA exposure was associated with endometrial disease, the genital tracts of 212 zoo felids (99 MGA treated and 113 control) representing 23 species were evaluated. Adenomatous and cystic hyperplasia were prevalent in both MGA-treated (85%) and control (61%) groups, and the risk of developing these lesions increased with age. Treatment with MGA further increased the risk of developing advanced hyperplasia regardless of dose, and treatment for >72 months significantly elevated that risk, whereas parous animals had a lower risk. Endometrial polyps, fibrosis, adenomyosis, and hydrometra occurred in both MGA-treated and control animals. MGA treatment was associated with an increased risk of hydrometra and mineralization but not of adenomyosis, polyps, or fibrosis after adjusting for advanced hyperplasia. Acute or chronic endometritis were associated with advanced hyperplasia but not with MGA treatment. These results indicate that proliferative and inflammatory endometrial lesions are common spontaneous diseases in zoo cats, and MGA contraceptives increase the risk of some diseases. The association of MGA with endometrial lesions that could impair fertility should be considered when using this contraceptive in genetically valuable felids.  相似文献   

2.
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.  相似文献   

3.
BACKGROUND: The use of computer-based image analysis systems in veterinary oncology has increased. Computerized morphometry is a part of image analysis that describes geometric figures of cellular structures in any dimension. Most investigators have performed morphometric analysis on histologic specimens. Computer-assisted nuclear cytomorphometry can provide important preoperative information on neoplastic lesions in animals. OBJECTIVES: The aim of this study was to define whether the morphometric parameters of mean nuclear diameter and nuclear roundness could be used to differentiate benign from malignant canine mammary gland tumors on cytologic specimens. METHODS: Mean nuclear diameter and nuclear roundness were determined by computer-assisted morphometry of epithelial cells in Hemacolor-stained cytologic smears from normal canine mammary gland (n = 7) and from canine mammary adenomas (n = 8), tubulopapillary carcinomas (n = 9), and solid carcinomas (n = 6). Data were analyzed by the Mann-Whitney U test. RESULTS: Significant differences (P <.001) were found in mean nuclear diameter and nuclear roundness among all tumor types and in comparison with normal canine mammary gland epithelial cells (except for nuclear roundness between tubulopapillary carcinomas and solid carcinomas). CONCLUSIONS: The morphometric parameters of mean nuclear diameter and nuclear roundness can be used in the preoperative differentiation of benign from malignant canine mammary gland tumors.  相似文献   

4.
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.  相似文献   

5.
BACKGROUND: Fractal geometry is a tool that can be used for describing, modeling, analyzing, and processing irregular and complex figures. Past investigations in medicine have revealed that fractal analysis could also be applied in tumor pathology to characterize irregular boundaries of the nuclei of tumor cells. OBJECTIVE: The aim of this study was to define whether the fractal dimension parameter could be used on cytologic specimens to differentiate benign from malignant canine mammary gland epithelial tumors. METHODS: The fractal dimension of nuclear surface was determined by computer-assisted morphometry on Hemacolor-stained cytologic smears obtained by fine needle aspiration of normal canine mammary gland epithelial cells, and cells in mammary adenomas, tubulopapillary carcinomas, solid carcinomas, and anaplastic carcinomas. Data were analyzed by Mann-Whitney U test. RESULTS: Significant differences (P <.001) were observed in mean fractal dimension among all tumor types and in comparison with normal canine mammary gland epithelial cells (except for the fractal dimension between solid carcinomas and anaplastic carcinomas). CONCLUSION: The morphometric parameter, fractal dimension, could help in the diagnostic discrimination between benign and malignant canine mammary gland epithelial tumors on cytologic specimens.  相似文献   

6.
Several immunohistochemical markers have been used to demonstrate the presence of myoepithelial cells in order to determine their role in the histogenesis of mammary tumors. p63, a recently characterized p53 homologue, is consistently expressed in myoepithelial cells of the human breast; however, no assessment of its immunoreactivity has been reported so far in canine mammary tissues. We investigated p63 immunohistochemical expression, as a novel myoepithelial cell nuclear marker, in 81 samples of normal (n = 2), hyperplastic (n = 11), and neoplastic (n = 68) canine mammary tissues. Myoepithelial phenotype was confirmed by using complementary monoclonal antibodies: alpha-smooth muscle actin, cytokeratin 14, cytokeratin AE1/AE3, and vimentin. p63 expression was observed in 91.4% (74/81) of the samples evaluated. Normal mammary glands, mammary hyperplasias, and benign tumors showed 100% immunoreactivity, with p63 expression restricted to myoepithelial cell nuclei. In general, benign mixed tumors showed a basal cell compartment immunoreactive to p63, with a gradual decrease of its expression during myoepithelial transformation. p63 expression was found in 72% of malignant tumors, allowing myoepithelial or basal cell identification in spindle-cell carcinomas (2/2), tubulopapillary carcinomas (8/9), solid carcinomas (7/10), and carcinosarcomas (1/3). The osteosarcoma analyzed was p63 negative. In our series, stromal components were consistently nonreactive to p63. In conclusion, the present study reveals p63 as a sensitive and highly specific marker of myoepithelial cells in canine mammary tissues, and the authors suggest p63 as an additional marker for defining myoepithelial histogenesis.  相似文献   

7.
Stained cytological specimens from 35 feline mammary gland epithelial tumours (4 adenomas, 11 tubulopapillary carcinomas 13 solid carcinomas and 7 cribriform carcinomas) were analysed by computer-assisted nuclear morphometry. In each case, the nuclei of at least 100 neoplastic cells were measured, and the mean nuclear area (MNA), mean nuclear perimeter (MNP), mean nuclear diameter (MND) and nuclear roundness (NR) were calculated. The study aimed to evaluate (1) the possibility of using nuclear cytomorphometry as an auxiliary diagnostic method to differentiate between benign and malignant feline mammary gland epithelial tumours, and (2) the prognostic value of nuclear morphometry in feline mammary carcinomas. The results indicated that MNA, MNP, MND and NR could be a useful adjunct in diagnosis but are not reliable prognostic indicators for feline mammary gland carcinomas.  相似文献   

8.
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.  相似文献   

9.
Fifty-two spontaneous canine mammary gland tumours (fibroadenomas (n = 8), tubulopapillary carcinomas (n = 9), solid carcinomas (n = 6), anaplastic carcinomas (n = 7), fibrosarcomas (n = 9), liposarcomas (n = 9) and osteosarcomas (n = 4) were analysed by computer-assisted nuclear morphometry in Hemacolor-stained cytological specimens. Computerized cytomorphometry was performed and the nuclear area, nuclear perimeter and mean nuclear diameter of investigated tumours were assessed. A minimum of 100 nuclei per lesion were examined. The statistical analysis revealed statistically significant differences between benign and malignant neoplasms. The results indicated that computer-assisted nuclear morphometry could be used as an additional method for differentiation of benign from malignant canine mammary gland tumours in cytological specimens.  相似文献   

10.
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.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
Desmopressin (DDAVP) is a vasopressin peptide analog with hemostatic properties that has been successfully used during surgery in patients with bleeding disorders. Recently published experimental and clinical data indicate that perioperative administration of DDAVP can minimize spread and survival of residual mammary cancer cells. The central aim of this study was to explore the effect of perioperative DDAVP and its relation to histologic grade in bitches with locally advanced mammary carcinoma. Of the 32 dogs initially recruited, 28 intact bitches with mammary carcinoma tumors stage III or IV were ultimately included. These dogs were randomized to receive DDAVP at intravenous doses of 1 μg/kg (n=18) or saline solution as placebo (n=10). En bloc mastectomy of the affected gland(s) was performed. Tumor malignancy was graded by the method of Elston and Ellis into well-differentiated (grade 1), moderately differentiated (grade 2), or poorly differentiated (grade 3). DDAVP therapy significantly prolonged the disease-free survival (P<0.001) and overall survival (P<0.01) in bitches with grade 2 or 3 carcinomas compared with bitches in the control group. No significant difference in disease-free period or overall survival was found between treatment groups in bitches with grade 1 tumors. The present data suggest that DDAVP may be an excellent candidate as a surgical adjuvant in the management of aggressive cancers in small animals. More research in this field is warranted.  相似文献   

14.
Thoracic radiographs of 25 cats with pulmonary metastatic disease and confirmed primary tumors were reviewed retrospectively. Pulmonary patterns of metastasis were divided into three categories, described as well-defined interstitial nodules, ill-defined interstitial nodules or a diffuse pulmonary pattern. The latter consisted of an alveolar pattern with or without ill-defined pulmonary nodules and/or pleural effusion. More cats presented with pulmonary metastatic disease in the category of either ill-defined nodules (n = 10) or a diffuse pattern (n = 7). Within this group, the most commonly represented primary tumor was mammary gland adenocarcinoma.  相似文献   

15.
Biotinylated lectins and avidin-biotin-peroxidase complex were used to study the correlation between cellular glycoconjugates' expression and squamous maturation in normal canine skin and in various epithelial neoplasms. Normal skin tissue was obtained from five, male, random-source dogs, 5 to 7 years old. The tumors tested, selected from the files of our Department, were fifteen squamous cell carcinomas from different tissue origin, five hepatoid perianal gland adenocarcinomas with squamous metaplasia, and fourteen solid mammary carcinomas with and without histologic evidence of squamous metaplasia. Except for mammary gland carcinomas, all tumors had been surgically excised from male dogs. Intermediate filament aggregation of twelve solid mammary gland carcinomas were studied electron microscopically. The basal and the lower spinous cells in normal skin and the less differentiated cells in squamous cell carcinomas stained moderately with Griffonia simplicifolia agglutinin-I. Spinous and granular cell layers stained strongly with Phytolacca americana mitogen and Arachis hypogaea agglutinin. Both lectins stained well-differentiated cells in squamous cell carcinomas. The electron microscopic study carried out in solid carcinomas of mammary glands revealed some relationship between the presence of intracytoplasmic tonofibrils and the binding of Griffonia simplicifolia agglutinin-I and Phytolacca americana mitogen to the tumors tested. Our results suggest that the glycosylation pattern occurring during normal keratinocyte differentiation is conserved in squamous cell carcinomas and that Griffonia simplicifolia agglutinin-I and Phytolacca americana mitogen may represent useful tools in distinguishing poorly differentiated squamous cell carcinomas from other poorly differentiated mammary epithelial tumors.  相似文献   

16.
Summary

Ten malignant canine mammary gland tumours and five metastases from three of these tumours were studied immunohistochemically with monoclonal antibodies (MoAbs) directed against different human keratin types (K), α‐smooth muscle actin, vimentin, and desmin.

In all tumours the neoplastic epithelium was rather homogeneously labelled with the keratin MoAbs RCK 102 (K 5 and 8) and CAM 5.2 (K 8). The adenocarcinomas (n=5), the solid carcinomas (n=2), and the carcinosarcoma (n=1) showed heterogeneous labelling with the MoAbs specific for luminal cell antigens in the normal canine mammary gland, i.e., K 18, K 7 and K 19 MoAbs. These cells were also immunoreactive with K 4 and K 10 MoAbs. The spindle cell carcinomas (n=2), however, did not react with these MoAbs.

All tumours except one adenocarcinoma were characterized by the absence of immunoreactive labelling with the α‐smooth muscle actin MoAb. In the solid carcinomas this was associated with the absence of labelling with one or both basal cell specific keratin MoAbs, i.e., 8.7 (K 14 and 17) and RCK 107 (K 14), respectively. In contrast, the other malignant tumours showed marked labelling of neoplastic epithelium with these MoAbs. Another remarkable finding was the labelling of a limited to moderate number of neoplastic epithelial cells with the vimentin MoAb. The presence of such labelling patterns in canine mammary gland tumours may be indicative of malignancy. Metastatic tumour tissues had a labelling pattern largely similar to that of the primary tumour, although also loss of reactivity for some keratin MoAbs was seen.  相似文献   

17.
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.  相似文献   

18.
The p27 gene is a member of the cyclin-dependent kinase inhibitors, which arrest G1- to S-phase transition of the cell cycle. We have previously shown a significant reduction of p27 mRNA expression level in laser-microdissected mammary carcinomas and their lymph node metastases when compared to non-neoplastic mammary gland of the same dog. Here, p27 expression was analyzed on the protein level in non-neoplastic mammary gland, primary mammary carcinomas, their lymph node metastases and intravascular tumor cells of 49 dogs, adenomas of 49 dogs and non-neoplastic mammary gland of 98 dogs by immunohistochemistry. A significantly (p ? 0.05) decreased percentage of p27 positive tissue samples was found when normal gland was compared with adenomas, carcinomas and lymph node metastases. Specifically, 91% of normal gland epithelium displayed nuclear p27 expression. In contrast, only 22% of the adenomas, 20% of carcinomas, 12% of lymph node metastases and 32% of intravascular tumor cells had p27 reactivity. Cell cycle control by p27 is therefore lost in the majority of canine mammary tumors. The lack of significant differences between benign and malignant mammary tumors indicates that decreased p27 expression is an early step in carcinogenesis of canine mammary tumors and hinders the use of p27 as a marker of malignancy for this tumor type.  相似文献   

19.
Mammary tumors are the most common neoplasms in female dogs. Induction of cyclooxygenase-2 (COX-2) has been implicated in various cancers in humans. However, expression of COX-2 has not been investigated in canine mammary tumors. Normal mammary gland (n = 4), simple or complex adenomas (n = 63), and simple or complex adenocarcinomas (n = 84) were studied by immunohistochemistry. Results showed that COX-2 was not expressed in the normal gland but was detected in 24% of adenomas and in 56% of adenocarcinomas (P < 0.001). The incidence of COX-2 expression and the intensity of the COX-2 signal were higher in adenocarcinomas than in adenomas (P < 0.001). These results demonstrate for the first time that COX-2 is induced in a proportion of canine mammary tumors and that COX-2 expression is more frequent and more intense in malignant than in benign tumors, suggesting a potential role for COX-2 in canine mammary tumorigenesis.  相似文献   

20.
CD44 is an adhesion molecule implicated in the progression of human breast cancer. The purpose of this study was to describe CD44 antigen expression in canine mammary carcinomas and to evaluate its prognostic significance in relation to other clinico-pathological variables.A reduction in CD44 expression was significantly related to variables such as tumour size and adherence to underlying tissues but was not related to tumour location or to ulceration of the overlying skin. Complex (grade I) and anaplastic (grade III) carcinomas exhibited more intense expression of this antigen than did some tubulopapillary and most solid carcinomas (grade II). Although reduced CD44 expression was associated with infiltrative growth and vascular invasion in solid carcinomas, intense expression was also observed in anaplastic tumours. Although overall these findings suggest a role for this adhesion factor in canine mammary tumour development and progression, the complexity and apparently paradoxical nature of some of the findings currently limit the use of this immunohistochemical marker as a prognostic indicator.  相似文献   

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