Steroid hormone profile of canine inflammatory mammary carcinoma: a preliminary study

Inflammatory mammary carcinoma (IMC) is the most aggressive spontaneous type of mammary malignant tumor both in women and dogs. Latest studies in dogs indicate that different endocrine mechanisms seem to be involved in inflammatory carcinomas (IMCs). The aim of the present study was to characterize the steroid hormone profile of inflammatory carcinoma, and to compare it with mammary dysplasias, benign tumors and other malignant tumors. Eighty-six mammary samples (10 normal mammary tissue, 21 dysplasias, 26 benign, 22 malignant, and 7 IMC) from 30 female dogs were used. Hormone levels of progesterone (P4), 17beta-estradiol (E2), androstenedione (A4), dehydroepiandrosterone (DHEA), and estrone sulphate (E1SO4) in tissue homogenates were measured by enzyme immunoassays (EIAs) techniques, previously validated for this species. IMC displayed the following steroid profile: P4: 13.80+/-0.56 microg/g; E2: 675.19+/-33.00 ng/g; A4: 631.73+/-70.73 microg/g; DHEA: 702.22+/-89.93 microg/g, and E1SO4: 2.84+/-0.32 mg/g. All of these hormones were significantly higher (P<0.001) compared with the hormone steroid profile determined for malignant, benign, dysplasias, and normal mammary tissue. The most relevant finding was the increased levels, two or three times, of both DHEA and E1SO4 in IMC respect to other groups (P<0.001). These results, together with the highest immunohistochemical expression of P450scc found in IMC, suggest the hypothesis that an autocrine mechanism could be especially involved in the development of canine inflammatory carcinoma.

Regeneration of transgenic citrus plants under non selective conditions results in high-frequency recovery of plants with silenced transgenes

Insertion of foreign DNA into plant genomes frequently results in the recovery of transgenic plants with silenced transgenes. To investigate to what extent regeneration under selective conditions limits the recovery of transgenic plants showing gene silencing in woody species, Mexican lime [ Citrus aurantifolia (Christm.) Swing.] plants were transformed with the p25 coat protein gene of Citrus tristeza virus (CTV) with or without selection for nptII and uidA. Strikingly, more than 30% of the transgenic limes regenerated under non-selective conditions had silenced transgenes, and in all cases silencing affected all the three transgenes incorporated. These results indicate that the frequency of transgene silencing may be greatly underestimated when the rate of silencing is estimated from the number of regenerants obtained under selective conditions. To our knowledge, this is the first report in which the frequency of gene silencing after transformation has been quantified. When the integration pattern of T-DNA was analyzed in silenced and non-silenced lines, it was observed that inverted repeats as well as direct repeats and even single integrations were able to trigger gene silencing. Gene silencing has often been associated with the insertion of DNA sequences as inverted repeats. Interestingly, here, direct repeats and single-copy insertions were found in both silenced and non-silenced lines, suggesting that the presence of inverted-repeat T-DNAs and the subsequent formation of dsRNAs triggering gene silencing cannot account for all silencing events.

Lingual calcinosis circumscripta in a dog

Calcinosis circumscripta occurs rarely in dogs and cats, especially in the oral cavity. This case report describes the diagnosis and management of lingual calcinosis circumscripta in an eight-month-old, intact/male German shepherd-cross dog. An excellent prognosis for this disease may be achieved when the patient is managed as described in this report.

Use of aminoglutethimide in the treatment of pituitary-dependent hyperadrenocorticism in the dog

The aim of this study was to evaluate the efficacy and safety of aminoglutethimide in the treatment of dogs with pituitary-dependent hyperadrenocorticism (PDH). Ten dogs were diagnosed with PDH based on clinical and laboratory data, adrenal function tests (adrenocorticotropic hormone [ACTH] stimulation test and urinary cortisol/creatinine ratio [UCCR] combined with a high dose oral dexamethasone suppression test) and ultrasonographic evaluation of the adrenal glands. Aminoglutethimide was administered daily at a dose of 15 mg/kg bodyweight for one month. Median basal cortisol concentration and post-ACTH cortisol concentration one month after treatment were significantly lower than pretreatment values. Complete response was achieved in one dog, and partial response was obtained in three dogs. Severe side effects of anorexia, vomiting and weakness occurred in one dog and medication was withdrawn. Two further dogs developed decompensations of concurrent diseases and medication was stopped in these animals as well. Mild toxicity occurred in four dogs. Moderate to severe elevations in liver enzymes occurred in all dogs. The efficacy of this drug is lower than that observed using mitotane and ketoconazole, and adverse effects limit its use. Aminoglutethimide, using the protocol described, cannot be recommended for long-term management of PDH in the dog.

Recent advances in the genetic transformation of trees

As the commercial production of transgenic annual crops becomes a reality in many parts of the world, many people wonder if the genetic engineering of perennial trees will allow their eventual commercialization. Not long ago, trees were considered to be recalcitrant material for most molecular biology techniques, including genetic transformation. However, transgenes for shortening the juvenile phase or for phytoremediation purposes have now been incorporated, and the alteration of lignin biosynthesis and increased cellulose accumulation in forest trees have also been accomplished. For long-lived tree species, new questions arise regarding the stability of integration and expression of foreign genes. Biosafety considerations, including transgene dispersion through the pollen and advances in strategies to avoid this, are also important.

Inflammatory mammary carcinoma in dogs: 33 cases (1995-1999)

OBJECTIVE

To determine epidemiologic, clinical, and pathologic characteristics of inflammatory mammary carcinoma (IC) in dogs.

DESIGN

Retrospective study.

ANIMALS

33 dogs with IC and 153 dogs with malignant mammary tumors other than IC.

PROCEDURES

Medical records were reviewed, and signalment, history, physical examination findings, and results of thoracic radiography and necropsy were obtained.

RESULTS

33 of 436 (7.6%) dogs examined at a veterinary teaching hospital because of dysplasia or tumors of the mammary glands and 33 of 186 (17.7%) dogs with at least 1 malignant tumor had IC. Thirty-two of the 33 dogs were sexually intact. Dogs with IC were significantly older than were dogs with other malignant mammary tumors, and in dogs with IC, the tumor was initially noticed a mean of 52 days after the beginning of the last observed estrus, whereas in dogs with other mammary tumors, the tumor was initially noticed a mean of 137 days after the beginning of the last observed estrus. Dogs with IC were more likely to be anorectic and to have generalized weakness, weight loss, and thoracic metastases. Dogs with IC survived a mean of 25 days with palliative treatment. Histologically, involvement of dermal lymphatic vessels was identified in 14 of 19 (74%) dogs with IC. Two clinical forms of IC (primary and secondary) were identified. Dogs with primary IC had a worse clinical condition.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that IC is an uncommon but distinct entity in dogs. A histologic finding of dermal lymphatic involvement should be considered a hallmark for the pathologic diagnosis of IC in dogs.

Constitutive expression of Arabidopsis LEAFY or APETALA1 genes in citrus reduces their generation time

Citrus trees have a long juvenile phase that delays their reproductive development by between 6 and 20 years, depending on the species. With the aim of accelerating their flowering time, we transformed juvenile citrus seedlings to constitutively express the Arabidopsis LEAFY (LFY) or APETALA1 (AP1) genes, which promote flower initiation in Arabidopsis. Both types of transgenic citrus produced fertile flowers and fruits as early as the first year, notably through a mechanism involving an appreciable shortening of their juvenile phase. Furthermore, expression of AP1 was as efficient as LFY in the initiation of flowers, and did not produce any severe developmental abnormality. Both types of transgenic trees flowered in consecutive years, and their flowering response was under environmental control. In addition, zygotic and nucellar derived transgenic seedlings had a very short juvenile phase and flowered in their first spring, demonstrating the stability and inheritance of this trait. These results open new possibilities for domestication, genetic improvement, and experimental research in citrus and other woody species.

Transgenic citrus plants expressing the citrus tristeza virus p23 protein exhibit viral-like symptoms

Summary The 23 kDa protein (p23) coded by the 3'-terminal gene of Citrus tristeza virus (CTV), a member of the genus Closterovirus with the largest genome among plant RNA viruses, is an RNA-binding protein that contains a motif rich in cysteine and histidine residues in the core of a putative zinc-finger domain. On this basis, a regulatory role for CTV replication or gene expression has been suggested for p23. To explore whether over-expression of this protein in transgenic plants could affect the normal CTV infection process, transgenic Mexican lime plants were generated carrying the p23 transgene, or a truncated version thereof, under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Constitutive expression of p23 induced phenotypic aberrations that resembled symptoms incited by CTV in non-transgenic lime plants, whereas transgenic plants expressing the p23 truncated version were normal. The onset of CTV-like symptoms in p23-transgenic plants was associated with the expression of p23, and its accumulation level paralleled the intensity of the symptoms. This demonstrates that p23 is involved in symptom development and that it most likely plays a key role in CTV pathogenesis. This is the first case in which a protein encoded by a woody plant-infecting RNA virus has been identified as being directly involved in pathogenesis in its natural host. This finding also delimits a small region of the large CTV genome for the future mapping of specific pathogenic determinants.

Factors influencing the incidence and prognosis of canine mammary tumours

Factors relating to the incidence of canine mammary tumours are reviewed. Increased age, intact status or ovariectomy after 2.5 years of age, as well as progestagen treatment, can all lead to an increased risk of mammary neoplasia in the bitch. In addition, obesity early in life, and a habitual diet based on home-made food (rich in beef and pork, and poor in chicken) as opposed to commercial food, are also associated with the occurrence of mammary tumours. Other aspects related to incidence are also discussed. Increased age at diagnosis, invasive growth (fixed to adjacent tissues), large tumour size, ulceration of skin, and axillary or inguinal node involvement are clinical parameters associated with a low chance of survival after surgical excision of mammary tumours. Histological typing and grading of the tumour allows the establishment of a prognosis, which is poor where there is tumour proliferation as measured by S-phase fraction determination and Ki-67 immunostaining.

Immunohistologic detection of estrogen receptor alpha in canine mammary tumors: clinical and pathologic associations and prognostic significance

Eighty-nine canine mammary tumors and dysplasias of 66 bitches were investigated to determine the immunohistochemical expression of classical estrogen receptor (ER-alpha) and its clinical and pathologic associations and prognostic value. A complete clinical examination was performed and reproductive history was evaluated. After surgery, all animals were followed-up for 18 months, with clinical examinations every 3-4 months. ER-alpha expression was higher in tumors of genitally intact and young bitches (P < 0.01, P < 0.01) and in animals with regular estrous periods (P = 0.03). Malignant tumors of the bitches with a previous clinical history of pseudopregnancy expressed significantly more ER-alpha (P = 0.04). Immunoexpression of ER-alpha decreased significantly with tumor size (P = 0.05) and skin ulceration (P = 0.01). Low levels of ER-alpha were significantly associated with lymph node involvement (P < 0.01). Malignant tumors had lower ER-alpha expression than did benign tumors (P < 0.01). Proliferation index measured by proliferating cell nuclear antigen immunostaining was inversely correlated with ER-alpha scores (P = 0.05) in all tumors. Low ER-alpha levels in primary malignant tumors were significantly associated with the occurrence of metastases in the follow-up (P = 0.03). Multivariate analyses were performed to determine the prognostic significance of some follow-up variables. ER-alpha value, Ki-67 index, and age were independent factors that could predict disease-free survival. Lymph node status, age, and ER-alpha index were independent prognostic factors for the overall survival. The immunohistochemical detection of ER-alpha in canine mammary tumors is a simple technique with prognostic value that could be useful in selecting appropriate hormonal therapy.

Efficient production of transgenic citrus plants expressing the coat protein gene of citrus tristeza virus

 The coat protein gene of citrus tristeza virus (CTV) has been introduced into Mexican lime (Citrus aurantifolia Swing.) plants by using an improved Agrobacterium-mediated genetic transformation system. Internodal stem segments from greenhouse-grown seedlings were co-cultivated with A. tumefaciens strain EHA 105 carrying the binary plasmid pBI 121/CTV-CP in a medium rich in auxins that provided the explant cells with the proper treatment to shift them to a competent state for transformation. The transformation frequency was enhanced, and this allowed us to recover 42 transgenic plants from 1200 explants. Regenerated shoots were identified as transformants by performing β-glucuronidase (GUS) assays and subsequently by PCR amplifications of the CTV-CP transgene. Southern analyses revealed that at least one copy of the CTV-CP gene was integrated in all PCR positive plants. Interestingly, 70% of them had linked T-DNAs arranged at one locus. Copy number of the CTV-CP gene varied from one to six among the transgenic lines. Half of them showed truncated T-DNAs in which the left border was lost. Expression of the CTV-CP transgene was demonstrated in 38 out of 42 plants by western analysis and DASI-ELISA. No correlation was found between coat protein expression and transgene copy number or integration pattern.

Pathological alterations caused by Anoplocephala perfoliata infection in the ileocaecal junction of equids

The pathological alterations caused by Anoplocephala perfoliata in the ileocaecal junction of 28 equids slaughtered in an abattoir in Madrid (Central Spain) are described. The lesions were scored in grades based on the intensity of the damage and were related to the tapeworm number observed. The first grade (grade I) of alterations consisted of a slight enteritis associated with focal erosions observed in 43% of parasitized animals with low parasitic burden (1-26 tapeworms). The second grade (grade II) was a focal pseudomembranous enteritis, present in the ileocaecal junctions of 36% infected animals with moderate to high burden (23-188 tapeworms), and the third grade (grade III) was a regional necrotizing enteritis, present in the animals (21%) with the highest burden (72-248 tapeworms). The possible role of the lesions caused by this parasite in the aetiology of colic is discussed.

Agrobacterium-mediated transformation of citrange: factors affecting transformation and regeneration

The effects of cocultivation with Agrobacterium tumefaciens, regeneration and selection conditions on the transformation efficiency of citrange (Citrus sinensis L. Osbeck×Poncirus trifoliata L. Raf.) have been investigated. Factors such as cocultivation period, preculture of explants, use of acetosyringone or feeder plates during cocultivation, cocultivation on a medium rich in auxins, postcultivation in darkness, and different kanamycin concentrations for selection were assessed. A 3-day cocultivation on a medium rich in auxins improved transformation frequencies, since it increased the number of dividing cells competent for transformation, at the cut ends of the explants. Exposure of explants to darkness for 4 weeks on selection medium resulted in further callus development and increased the regeneration frequency of transgenic shoots. Furthermore, this treatment drastically reduced the number of regenerated escape shoots. A transformation efficiency of 41.3% was achieved using the optimized transformation procedure.

[The relation of Helicobacter pylori with dysplasia and stomach neoplasms in Costa Rica]

Occurrence of the bacterium Helicobacter pylori was compared for two Costa Rican sites with contrasting levels of gastric cancer incidence, Poás (incidence 15.13%) and Puriscal (83.53%). A sample of 185 adults of similar age and sex proportions was studied in each site, using both H. pylori antiserum tests and gastroscopy to collect two biopsies per case. No clear association between H. pylori and gastric cancer was found.

Clinical and pathological prognostic factors in canine mammary tumors

In the present study, clinical and reproductive variables and pathological features were evaluated as prognostic factors in canine mammary tumor disease. Seventy-four female dogs free of distant metastases at diagnosis were followed-up during a period of 18 months after the surgical excision of mammary nodules. Age at presentation, tumor size, lymph node involvement, histological malignant grade and nuclear grade were proven to act as variables able to predict the overall survival time in dogs with mammary neoplasms. Disease free survival time was associated to the age, the presence of multiple malignant tumors, tumor size and ulceration of the skin.

Relation between habitual diet and canine mammary tumors in a case-control study

In the present case-control study several dietary and nutritional factors were investigated to determine if a relationship exists between diet and development of mammary tumors in female dogs. Control female dogs (n = 86) were compared with a case group of dogs (n = 102) with dysplasias or tumors of the mammary gland. A questionnaire providing information on the dog's body conformation and dietary and reproductive histories was answered by the owners. Serum selenium and retinol concentrations and the fatty acid profile in subcutaneous adipose tissue were analyzed as indicators of nutritional status. Obesity at 1 year of age and 1 year before the diagnosis of mammary nodules was found to be significantly related to a higher prevalence of mammary tumors and dysplasias. The intake of homemade meals (compared to that of commercial foods) was also significantly related to a higher incidence of tumors and dysplasias. Other significant risk factors were a high intake of red meat, especially beef and pork, and a low intake of chicken. The subcutaneous fatty acid profile and the serum selenium concentration were not significantly different in the cases and the controls, with the exception of C18:1 fatty acid (oleic acid) content, which was significantly higher in the cases than in healthy controls. Serum retinol concentration was significantly lower in the cases than in the controls. In the multivariate analysis, older age, obesity at 1 year of age, and a high red meat intake were independently and significantly associated with the risk of developing mammary tumor and dysplasias.

Binding of sodium salicylate by beta-cyclodextrin or 2,6-di-O-methyl-beta-cyclodextrin in aqueous solution

Speed of sound and conductivity experiments have been done at 298.15 K to study the encapsulation process of sodium salicylate (NaSA) by beta-cyclodextrin (beta-CD) and 2,6-di-O-methyl-beta-cyclodextrin (DIMEB) in aqueous solutions. Since the concentration of the salicyclic form (HSA), coming from the hydrolysis of SA-, is negligible at biological pH, the binding process studied in this work is that of the SA- species. The stoichiometries of the complexes DIMEB: SA- and beta-CD:SA- have been found to be 1:1, as usually determined for most CD:drug complexes. Their association constants and their ionic molar conductivities at infinite dilution have been obtained by fitting the experimental conductivity data with a nonlinear regression method (NLR). For that purpose, a model based on that of Gelb and co-workers has been used. From the values of K beta-CD:SA- = (105 +/- 15)M-1 and KDIMEB:SA- = (140 +/- 20)M-1 obtained, the bioavailability of the salicylate drug in the complexed form has been discussed.

An unusual late-onset case of propionic acidaemia: biochemical investigations, neuroradiological findings and mutation analysis

We report a 5-year-old boy with propionic acidaemia who developed a rapidly fatal necrosis of the basal ganglia after an episode of clinical deterioration. Neither metabolic acidosis nor hyperammonaemia were present. Organic acid analysis in both urine and CSF showed increased levels of methylcitric and 3-hydroxypropionic acids. Propionic acidaemia was confirmed by demonstrating a propionyl-CoA carboxylase deficiency (11% of control value) in skin fibroblasts. DNA analysis revealed that the patient was a compound heterozygote for two mutations in the PCCB gene.

CONCLUSION

Propionic acidaemia can present as a sudden and fatal neurological disease and not only as an organic aciduria with severe biochemical dis-turbances and progressive neurological deterioration.

Genetic transformation of lime (Citrus aurantifolia Swing.): factors affecting transformation and regeneration

We have previously developed procedures for the efficient production of sweet orange (Citrus sinensis L. Osbeck) and Carrizo citrange (C. sinensis L. Osbeck×Poncirus trifoliata L. Raf.) transgenic plants using an Agrobacterium tumefaciens-mediated transformation and shoot tip grafting in vitro regeneration system. We now report on the optimization of the cocultivation, regeneration and selection conditions for efficient and reliable production of transgenic lime (C. aurantifolia Swing.) plants. Improved transformation frequencies were obtained by cocultivating the explants with Agrobacterium on feeder plates. Optimum regeneration of transgenic shoots was obtained by exposing the explants to darkness for 2 weeks and by using kanamycin at 100 mg/l as selective agent. Attempts to use geneticin as selection antibiotic were not successful. Shoot tip grafting of regenerated shoots on Troyer citrange seedlings resulted in 100% successful production of transgenic plants. The presence and expression of the transferred genes in the regenerated plants was verified by β-glucuronidase histochemical and fluorimetric assays, neomycin phosphotransferase ELISA assays, PCR and Southern analyses.

Immunohistological study of IgA, IgG and IgM in endoscopic biopsies of dogs with plasmacytic-lymphocytic colitis

The results of a histological and immunohistochemical study of endoscopic colon biopsies of dogs with plasmacytic-lymphocytic colitis are reported. The histological study revealed that a characteristic infiltrate rich in lymphocytes and plasma cells was seen within the lamina propria in all the biopsies. The immunohistochemical investigation suggests that IgG is the major antibody in the immune response of dogs with plasmacytic-lymphocytic colitis.