Successful management with CHOP for pulmonary lymphomatoid granulomatosis in a dog.

A 3-year-old, spayed female miniature dachshund was presented for vomiting and anorexia. Thoracic radiographs and CT scan revealed abnormal pulmonary opacities at bilateral caudal lobe. Cytological analysis of the pulmonary mass revealed the presence of large lymphohistiocytic cells and small lymphocytes with occasional neutrophils and plasma cells. An open lung biopsy was performed and a diagnosis of pulmonary lymphomatoid granulomatosis (LYG) was made. The dog was administered CHOP based therapy (modified UW-25), and it survived for 1,022 days after admission. Immunohistochemistry revealed pulmonary lesions consisted of many CD79a positive B cells aggregation and proliferation with prominent angiocentric pattern. This was the first case of canine pulmonary LYG managed by CHOP chemotherapy.

Enzyme-linked immunosorbent assay for detection of canine chromogranin A by use of immunological cross-reactivity of rabbit anti-bovine chromogranin A antibody.

Bovine and canine chromogranin A were extracted and purified from each specie's adrenal glands. Isolated bovine 70 kDa protein showed 100% identity to bovine CgA reported previously, whereas isolated canine 68 kDa protein showed 83.3% identity to bovine CgA by the NH(2)-terminal amino acid sequence analysis. Rabbit antibody to purified bovine protein (CgA) was found to immunologically cross-reacted with purified canine protein (CgA). In sandwich ELISA with anti-bovine CgA, concentration-dependent curves were obtained ranging from 0.3 to 20 mug/ml for canine CgA. From these findings, sandwich ELISA with anti-bovine CgA is found to be useful to determine the concentration of canine CgA.

Measurement of plasma chromogranin A concentrations for assessment of stress responses in dogs with insulin-induced hypoglycemia.

OBJECTIVE: To determine whether cross-reactivity exists between canine chromogranin A (CgA) and anti-human CgA antibody and investigate the usefulness of plasma CgA concentration measurements as an index of acute stress responses in dogs. ANIMALS: 12 healthy Beagles. PROCEDURE: Canine CgA was extracted and purified from canine adrenal glands of cadaver dogs for studying cross-reactivity with anti-human CgA antibody. Western blotting with anti-human CgA antibody was performed. Blood samples were collected from dogs at 0, 10, 20, 30, 40, 60, 120, and 180 minutes after IV administration of saline (0.9% NaCl) solution or insulin. Canine plasma CgA concentrations were determined by use of a CgA ELISA kit with rabbit antiserum against the carboxy-terminal fragment of human CgA. Plasma cortisol and catecholamine (ie, norepinephrine and epinephrine) concentrations were measured by use of an ELISA and a high-performance liquid chromatography method, respectively. RESULTS: Purified canine CgA was specifically detected by use of western blot analysis and an ELISA with anti-human CgA antibody. An increase in plasma CgA concentrations was observed in insulin-induced hypoglycemic dogs. Changes in plasma CgA concentration were correlated with changes in plasma cortisol or catecholamine concentrations of hypoglycemic dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Use of the CgA ELISA kit for determination of human plasma CgA concentrations is applicable to the measurement of canine plasma CgA concentrations. Canine plasma CgA concentrations, along with measurements of plasma cortisol and catecholamine concentrations, correctly reflect insulin-induced hypoglycemic stressed conditions in dogs. Measurement of canine plasma CgA concentrations may provide a useful index for evaluation of an acute stress response.

Effect of ovarian hormones on periodical changes in immune resistance associated with estrous cycle in the beagle bitch.

In bitches, the onset of pyometra, an infection of the uterus, characteristically occurs in the first half of the diestrous stage in the estrous cycle, in which the blood concentration of progesterone peaks and that of estradiol-17beta is lowest. To investigate the immunological mechanisms governing stage-specific onset of pyometra, peripheral blood mononuclear cells (PBMNCs) were collected from beagle bitches during different stages of the estrous cycle and examined using various immunological assays. When we examined the proliferative response of PBMNCs to PYO-252, that is a clone of Escherichia coli isolated from the uterus of a dog afflicted with pyometra, the response of PBMNCs significantly decreased in the first half (day 10) of diestrus, but increased in proestrus/estrus. No significant differences were observed in the responses to concanavaline A between stages of the cycle. Throughout the estrous cycle, canine PBMNCs did not respond to lipopolysaccharide derived from E. coli. The response of PBMNCs collected in anestrus to PYO-252 was significantly enhanced upon the addition of estradiol-17beta to the culture. In contrast, these responses were significantly suppressed in the presence of progesterone. Progesterone progenitor or metabolite molecules, which have a low affinity for the progesterone receptor, did not affect proliferative responses. Expression of gamma interferon (IFNgamma) in response to PYO-252 was also significantly enhanced by estradiol-17beta, but suppressed by progesterone. This evidence suggests that in the first half of the diestrous stage, suppressed activity of cellular immunity results from increasing progesterone concentration and minimal estrogen release. This marked decrease of immune resistance allows the expansion of E. coli, which enter the uterine cavity through the loosened cervical canal during estrus, leading to pyometra onset.

Immunophenotypical changes of neoplastic cells and tumor-associated macrophages in a rat dendritic cell sarcoma-derived transplantable tumor line (KB-D8).

Basically, dendritic cell-derived sarcomas are characterized by expression of major histocompatibility complex class-II molecules, but the biological properties of the tumor cells remain to be elucidated. Recently, we established a novel transplantable cell line (KB-D8) from a dendritic cell sarcoma found in an F344 rat. In the present study, we investigated immunophenotypical changes of KB-D8 tumor cells and tumor-associated macrophages (TAMs) appearing in relation to tumor development in syngeneic F344 rats. A number of neoplastic cells in 0.5-cm-diameter KB-D8 tumors showed immunoreactions to OX6 (specific for rat antigen-presenting cells), ED1 (for rat exudate macrophages), and ED2 (for rat resident macrophages), and 72% and 11% of the OX6+ cells were double-immunostained with ED1 and ED2, respectively. Interestingly, the immunoreactions to these antibodies were gradually reduced with increasing size of KB-D8 tumors of 1-, 2-, and 3-cm diameter. These findings indicated that immunophenotypes of dendritic cell-derived sarcomas may be changeable depending on microenvironmental conditions in vivo. Many TAMs seen outside KB-D8 tumors reacted to OX6, ED1, and ED2; the numbers of TAMs immunopositive for these antibodies also decreased as the tumor grew. Similarly, the earlier temporary increase and subsequent gradual decrease in ED2+ and OX6+ cell numbers were observed in the spleen and liver of KB-D8-bearing rats. The reverse-transcription polymerase chain reaction showed mRNA expressions of granulocyte/macrophage-colony stimulating factor, monocyte-chemoattractant protein-1, and osteopontin in KB-D8 tumor tissues. Although the functional roles (biphasic roles: suppressing or promoting) of these factors should be investigated further in relation to tumor development, the factors might be partially responsible for the TAM reactions. KB-D8 would be a useful experimental model to investigate the biological characteristics of dendritic cell sarcomas and tumor immunology in the host.

Immunohistochemical and morphometrical studies on myelin breakdown in the demyelination (dmy) mutant rat.

The demyelination (dmy) rat is a unique mutant exhibiting severe myelin breakdown in the central nervous system (CNS). In this study, we conducted immunohistochemical and morphometrical investigations in the dmy rat. From around 6 weeks of age, the affected rats developed ataxia especially in the hindlimbs. Afterwards, ataxia worsened rapidly, resulting in complete paralysis of the hindlimbs and recumbency. Histopathology at 7 to 10 weeks of age revealed myelin destruction throughout the white matter of the CNS in the dmy rats. The most severely affected lesions were distributed in the corpus callosum, capsula interna, striatum, subcortical white matter, cerebellar peduncle, and ventral and lateral parts of the spinal cord. Immunohistochemistry demonstrated prominent astrogliosis and many ED-1 positive macrophages in the myelin-destructed areas. Until the 4th week, no significant differences in myelin thickness and fiber diameter were found between dmy and control rats. However, from 5 weeks of age, myelin thickness of residual myelinated fibers in dmy rats became significantly less than that in controls. These data indicated that the dmy phenotype shows a prolonged period of myelin destruction, suggesting that dmy mutation affects the adequate maintenance of myelin.

Expression of estrogen receptor alpha and beta genes in the mediobasal hypothalamus, pituitary and ovary during the canine estrous cycle.

Estrogen receptor alpha (ERalpha) and ERbeta mRNA levels were measured in the mediobasal hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERbeta gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERalpha and beta mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERalpha mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P<0.01), whereas ERbeta mRNA levels increased from mid anestrus to proestrus and were positively correlated with plasma estradiol-17beta levels (r=0.73, P<0.001). These results suggest that the rise in hypothalamic and pituitary ERalpha and beta mRNAs is associated with termination of anestrus, and that increases in ovarian ERalpha and beta mRNAs may be involved in initiating development of the follicle or corpora lutea.

Enhancement of aromatase gene expression in the mediobasal hypothalamus during anestrus in the beagle bitch.

The relationships among expression of cytochrome p450 aromatase (p450arom) mRNA in the mediobasal hypothalamus (MBH), ovarian aromatase activity, and estrogen secretion were examined throughout the estrous cycle in beagle bitches. Using polymerase chain reaction (PCR) analysis we were able to detect p450arom gene transcripts in the canine MBH. The level of hypothalamic p450arom mRNA increased during the progression of anestrus and declined thereafter. Ovarian p450arom activity, as measured by a (3)H2O assay, were low in anestrus, increased in proestrus, and declined thereafter. Ovarian p450arom activity and plasma estradiol-17beta levels were positively correlated (r=0.77, P<0.05). These results suggest that enhancement of hypothalamic p450arom gene expression is associated with termination of anestrus.

Isolation and characterization of embryonic stem-like cells from canine blastocysts.

Embryonic stem (ES) cells are pluripotent cells with the capacity to generate any type of cell. Here we describe the isolation of ES-like cells from canine blastocysts. Canine embryos were collected from beagle bitches at day 11-16 of first estrus. A total of 80 normal embryos were obtained from 15 dogs. Of the embryos, 13 were at the morulae stage, 39 at the blastocyst stage, and 28 at the hatched blastocyst stage. The inside of morulae or inner cell masses (ICMs) of blastocysts were isolated mechanically, and cultured onto mouse embryonic fibroblasts (MEF) as feeder layers. Primary cell colonies were formed in 0% (0/13) of morulae, 25.6% (10/39) of blastocysts, and 67.9% (19/28) of hatched blastocysts. These colonies were separated either by enzymatic dissociation or by mechanical disaggregation. Dissociation with collagenase resulted in immediate differentiation, but with mechanical disaggregation these cells remained undifferentiated, and two ES-like cell lines (cES1, cES2) continued to grow in culture after eight passages. These cells had typical stem cell-like morphology and expressed specific markers such as alkaline phosphatase activity, stage specific embryonic antigen-1 and Oct-4. These cells formed embryoid bodies (EBs) in a suspension culture; extended culture of EBs resulted in the formation of cystic EBs. When the simple EBs were cultured on tissue culture plates, they differentiated into several types of cells including neuron-like, epithelium-like, fibroblast-like, melanocyte-like, and myocardium-like cells. These observations indicate that we successfully isolated and characterized canine ES-like cells.

Establishment of a transplantable rat pulmonary carcinoma-derived cell line (IP-B12) as a new model of humoral hypercalcemia of malignancy and bone metastasis.

A cloned cell line (IP-B12) derived from a transplantable rat pulmonary carcinoma (IP), of which neoplastic cells produce parathyroid hormone-related protein (PTHrP), was established. Tumors induced in syngeneic F344 rats by intraperitoneal injection of IP-B12 cells had features of pulmonary adenocarcinomas, consisting of neoplastic cells immunopositive to PTHrP. The IP-B12 tumor-bearing rats developed severe emaciation and hypercalcemia, with a marked elevation of plasma PTHrP level; there was an increase in osteoclastic areas of the femur and calcium depositions in systemic organs, indicating progression to humoral hypercalcemia of malignancy (HHM) in the tumor-bearing rats. In addition, the injection of IP-B12 cells into the left cardiac ventricle of syngeneic rats resulted in osteolytic skeletal metastases in the long bones and vertebrae. In the metastatic lesions, histologically, neoplastic cells showed an immunopositive reaction to PTHrP, and a prominent osteoclastic activity was seen; bone lesions, including osteolysis, fracture, and nerve compression as well as replacement of bone marrow cells by proliferated tumor cells were similar to those reported in human cancer patients with bone metastases. IP-B12 is a new animal model for HHM and osteolytic bone metastases, and will become a useful tool for studies on the pathogenesis and therapeutic strategies for such conditions.