Gastric emphysema and pneumatosis intestinalis in two common marmosets with duodenal dilation syndrome.

BACKGROUND: Common marmosets (Callithrix jacchus) are widely used as primate experimental models in biomedical research. Duodenal dilation with chronic vomiting in captive common marmosets is a recently described life-threatening syndrome that is problematic for health control. However, the pathogenesis and cause of death are not fully understood. CASE PRESENTATION: We report two novel necropsy cases in which captive common marmosets were histopathologically diagnosed with gastric emphysema (GE) and pneumatosis intestinalis (PI). Marmoset duodenal dilation syndrome was confirmed in each case by clinical observation of chronic vomiting and by gross necropsy findings showing a dilated, gas-filled and fluid-filled descending duodenum that adhered to the ascending colon. A diagnosis of GE and PI was made on the basis of the bubble-like morphology of the gastric and intestinal mucosa, with histological examination revealing numerous vacuoles diffused throughout the lamina propria mucosae and submucosa. Immunostaining for prospero homeobox 1 and CD31 distinguished gas cysts from blood and lymph vessels. The presence of hepatic portal venous gas in case 1 and possible secondary bacteremia-related septic shock in case 2 were suggested to be acute life-threatening abdominal processes resulting from gastric emphysema and pneumatosis intestinalis. CONCLUSIONS: In both cases, the gross and histopathological findings of gas cysts in the GI tract walls matched the features of human GE and PI. These findings contribute to clarifying the cause of death in captive marmosets that have died of gastrointestinal diseases.

Cutaneous anaphylactoid reaction to polyoxyethylene hydrogenated castor oil in dogs.

BACKGROUND: Polyoxyethylene hydrogenated castor oil (HCO ethoxylates) is a nonionic surfactant used as an excipient for ointments and injections in human and veterinary drugs. Several polyethylene glycol (PEG) derivatives can be obtained depending on the number of moles of ethylene oxide (EO). HCO ethoxylates have the potential to cause anaphylactoid reactions. There is little published information about these types of reactions in dogs. OBJECTIVE: To determine the potential for HCO-ethoxylate-containing drugs to cause anaphylactoid reactions in dogs, employing intradermal testing (IDT) with various concentrations of HCO ethoxylates (HCO-25, -40, -60 and -80). ANIMALS: Four healthy male laboratory dogs. MATERIALS AND METHODS: We performed IDT with drugs containing HCO ethoxylates and HCO ethoxylates alone to determine threshold concentrations. The IDT scores and threshold concentrations were compared. Analysis of skin biopsies from IDT sites was used to measure the percentage of degranulated mast cells. The effect of histamine at IDT sites was investigated by pre-treatment with an antihistamine. RESULTS: All HCO-ethoxylate-containing drugs caused a wheal-and-flare reaction. The threshold concentrations (0.001% and 0.00001%) of each HCO-ethoxylate depended on the number of moles of EO (p < 0.05). Mast cell degranulation was enhanced by all HCO ethoxylates. The HCO-60-induced reaction was suppressed by an oral antihistamine. CONCLUSIONS AND CLINICAL RELEVANCE: The threshold concentration can serve as a consideration for developing safe new drug formulations and for clinical decision-making around using drugs containing PEG derivatives. IDT is useful to predict the risk of adverse effects. Antihistamines could demonstrate a prophylactic effect.

Recurrence analysis of intraoperative acridine orange-photodynamic therapy for dogs with intranasal tumors.

Intraoperative acridine orange-photodynamic therapy (AO-PDT) and cribriform plate irradiation are used to treat canine intranasal tumors. The purpose of this study was to evaluate the effects of AO-PDT on intranasal tumors and the recurrence rate of tumors after this treatment. Treatments with AO-PDT were performed on 38 dogs through a narrow window of the dorsal nasal cavity. The median progression-free interval was 12 mo and recurrence was detected in 21 dogs. Based on computed tomography, recurrence in 16 dogs was biased to the following areas: lateral (n = 10), medial (n = 2), ventral (n = 0), rostral (n = 0), and caudal (n = 8). Side effects were mild and included subcutaneous emphysema and rhinitis. The median survival time was 24 mo. Although AO-PDT with cribriform irradiation is an effective treatment for intranasal tumors, AO-PDT techniques should be improved to treat the nasal cavity more uniformly and thoroughly.

Analyse de récurrence de la thérapie photodynamique peropératoire à l'acridine orange pour des chiens atteints de tumeurs intranasales. La thérapie photodynamique peropératoire à l'acridine orange (AO-PDT) et l'irradiation de la plaque cribriforme sont utilisées pour traiter les tumeurs intranasales canines. Le but de cette étude était d'évaluer les effets de l'AO-PDT sur les tumeurs intranasales et le taux de récidive des tumeurs après ce traitement. Des traitements avec AO-PDT ont été effectués sur 38 chiens à travers une fenêtre étroite de la cavité nasale dorsale. L'intervalle médian sans progression était de 12 mois et une récidive a été détectée chez 21 chiens. Sur la base de la tomodensitométrie, la récidive chez 16 chiens était biaisée dans les zones suivantes : latérale (n = 10), médiale (n = 2), ventrale (n = 0), rostrale (n = 0) et caudale (n = 8). Les effets secondaires étaient légers et comprenaient l'emphysème sous-cutané et la rhinite. La durée médiane de survie était de 24 mois. Bien que l'AO-PDT avec irradiation de la plaque cribriforme soit un traitement efficace pour les tumeurs intranasales, les techniques d'AO-PDT devraient être améliorées pour traiter la cavité nasale de manière plus uniforme et plus complète.(Traduit par Dr Serge Messier).

Safety of alternate-day treatment with TS-1TM (tegafur/gimeracil/oteracil) in tumor-bearing dogs: a pilot study.

Tegafur is a prodrug of fluoropyrimidine 5-fluorouracil (5-FU), while TS-1TM is an oral fixed-dose combination of three active drugs, tegafur, gimeracil, and oteracil. This pilot study evaluated the safety of tegafur/gimeracil/oteracil in the treatment of cancers in dogs. Tegafur/gimeracil/oteracil was administered orally at a mean dose of 1.1 mg/kg twice daily on alternate days, Monday-Wednesday-Friday, every week to 11 dogs with tumors. Partial response and stable disease were observed in one dog each, whereas six exhibited progressive disease. Three dogs were not assessed. Adverse events, the most serious being grade 2, were noted in seven dogs. Adverse events were acceptable, and the drug was effective in some dogs. Therefore, tegafur/gimeracil/oteracil may be useful for treating malignant solid tumors in canines.

Serum concentration and safety of intravenous drip versus subcutaneous administration of carboplatin in dogs.

Carboplatin is used to treat certain cancers in dogs and cats and is routinely administered via intravenous drip (IVD). Subcutaneous (SC) administration has also been described. However, the toxicity, serum concentrations, and area under blood concentration-time curves (AUCs) of SC carboplatin are unknown. This study aimed to compare serum carboplatin concentrations in dogs after SC and IVD and to monitor any adverse events. In this crossover study, five dogs received SC or IV carboplatin (300 mg/m2). After a minimum of 3 weeks, each dog received the other treatment. No gross skin toxicity or abnormal clinical signs were observed in any of the dogs. Blood test abnormalities were detected in most dogs. Decreased neutrophil and platelet counts, and increased C-reactive protein (CRP) levels were found. There was no significant difference in the neutropenia, thrombocytopenia, and CRP scores between the groups. Systemic toxicities of SC carboplatin were comparable to those of IVD carboplatin. The time to maximum carboplatin concentration after SC was longer than that after IVD (P<0.001). SC carboplatin remained in the serum longer than IVD carboplatin (P=0.008). The AUC of SC was less than that of IVD (P=0.002). The AUC and time taken to reach the maximum concentration of SC carboplatin were lower than those of IVD carboplatin. This study suggests that SC carboplatin may be an efficacious option for the treatment of tumors in dogs, particularly where IVD administration is challenging.

Application of a novel carboxymethyl cellulose-based Mohs sol-gel on malignant wounds in three dogs.

The preparation of modified Mohs paste, commonly used for malignant wounds, requires time and effort. Moreover, metal-containing liquid waste is generated when malignant wounds are scrubbed. Therefore, we previously changed the base material of the modified Mohs paste from zinc oxide starch powder to carboxymethyl cellulose (CMC). The novel modified Mohs paste based on CMC (moM-CMC sol) may reduce these disadvantages. In the present study, the moM-CMC sol was applied to malignant tumors in three dogs to manage bleeding and malodor. The moM-CMC sol transitioned into a gel on the tumors within an hour of application and could be easily removed. The symptoms resolved in all cases. The moM-CMC sol could be beneficial for dogs with malignant wounds.

Intraoperative acridine orange photodynamic therapy and cribriform electron-beam irradiation for canine intranasal carcinomas: 14 cases.

Canine intranasal carcinomas are almost always malignant. Surgery alone often results in rapid tumor regrowth. Radiotherapy is the treatment of choice for dogs with intranasal tumors. Here, we retrospectively assessed treatment of intranasal carcinoma by marginal tumor resection followed by intraoperative acridine orange (AO) photodynamic therapy (PDT) and cribriform plate electron-beam intraoperative radiotherapy (IORT). Fourteen canine cases were assessed, 12 of which had stage I tumors, one with stage III, and one with stage IV. Recurrence was detected in 8, with a median recurrence from the time of treatment of 6 months (range: 3 to 16 months). The median progression-free survival time and overall survival time after treatment were 13 and 22 months, respectively. Adverse events were mild. Marginal tumor resection followed by intraoperative AO-PDT and cribriform plate electron-beam IORT may increase the tumor control time in dogs with marginally resectable intranasal malignant tumors beyond that incurred by surgery alone.

Thérapie photodynamique peropératoire à l'acridine orange et irradiation par faisceau électrique pour carcinome intranasal canin : 14 cas. Un carcinome intranasal canin est presque toujours malin. Une simple opération chirurgicale résulte souvent dans la rapide réapparition de la tumeur. Dans cet article, nous discutons d'un traitement d'un carcinome intranasal par résection marginale de la tumeur effectué simultanément à une thérapie photodynamique (TPD) peropératoire à l'acridine orange (AO) et une radiothérapie peropératoire (RPO) par faisceau électrique des lames criblées. L'étude a porté sur quatorze cas chez le chien dont 12 tumeurs étaient classées au stade I, une au stade III et une au stade IV. Huit des cas étaient des cas de récidive selon une moyenne de 6 mois depuis la période du traitement (plage de 3 à 16 mois). Le temps de survie moyen à l'état stabilisé et le temps de survie général après traitement étaient respectivement de 13 et 22 mois. Les incidents thérapeutiques sont moindres (cinq cas d'emphysème sous-cutané et quatre cas de rhinite). La résection marginale de la tumeur conduite simultanément avec une TPD-AO peropératoire et une RPO par faisceau électrique des lames criblées semble permettre une plus longue phase de maîtrise des tumeurs chez le chien porteur d'une tumeur intranasale maligne à résection marginales possible par rapport aux résultats obtenus par simple intervention chirurgicale.(Traduit par les auteurs).

Eosinophilic plasmacytic conjunctivitis concurrent with gingival fistula caused by Schizophyllum commune in a captive cheetah (Acinonyx jubatus).

We describe for the first time the diagnosis of Schizophyllum commune infection in a captive cheetah. Eosinophilic plasmacytic conjunctivitis was detected histopathologically in a biopsy specimen. Both a second surgical specimen and drainage fluid from a gingival mass and fistula contained fungal hyphae in giant cells with granulomatous inflammation. Allergic S. commune mycosis was suspected at this point. A monokaryotic isolate was characterized morphologically, and then identified genetically. Treatment with itraconazole and pimaricin was effective.

Cutaneous epitheliotropic T-cell lymphoma with systemic dissemination in a dog.

Cutaneous epitheliotropic T-cell lymphoma (CETL) is characterized by neoplastic T-cell infiltration of the epidermis, adnexal structures, and oral mucosa. The objective of this report was to describe the pathological findings of a canine case of terminal-stage CETL. A 10-year-old, mixed-breed, neutered male dog was presented with erosion of the oral mucosa and mucocutaneous junction. The dog was diagnosed with CETL with no evidence of metastasis. Despite chemotherapy, the dog was re-presented with oral pain, vomiting, and diarrhea, and died 17 months after the first visit to the hospital. A complete autopsy was performed. Histologic examination of the primary lesion and systemic organs was performed. Gross examination revealed an advanced-stage oral lesion. Distinct tumor formation was not observed in the primary sites and systemic organs. Histologically, the primary oral lesion was characterized by massive intraepithelial infiltration of a large number of neoplastic lymphocytes. The neoplastic cells in the metastatic sites also showed exclusive epitheliotropic proliferation in organs, including the trachea, tonsils, esophagus, stomach, small intestine, colon, anal mucosa, liver, pancreas, kidneys, urinary bladder, prostate gland, ear canals, and auricular and ventral skin. Immunohistochemically, the neoplastic cells were positive for CD3 and negative for CD20 as well as CD79α, supporting a diagnosis of CETL with systemic dissemination. In canine CETL with systemic signs, systemic metastasis should be considered even without evident mass formation. Neoplastic lymphocytes of CETL showed distinct epitheliotropism even in the systemic metastatic sites.

The palliative efficacy of modified Mohs paste for controlling canine and feline malignant skin wounds.

In veterinary medicine, the management of malignant skin wounds is highly challenging. We conducted a study on seven case animals (four dogs and three cats) which presented with malignant skin wounds. All seven animals had signs and symptoms which were controlled following treatment with a modified Mohs paste. Upon obtaining informed consent from their owners, the animals requiring management of malignant wounds were enrolled in this study. The modified Mohs paste was prepared by mixing zinc chloride, zinc oxide starch powder, glycerin, and distilled water. The modified Mohs paste was topically applied to and left to remain on the malignant wounds for one hour, under controlled conditions. Once the paste was removed, the wounds were irrigated with a solution of sterile saline. At the first examination, the wounds of each animal were observed for signs of exudate, malodor, and bleeding. In every case, visible improvement was observed immediately after the modified Mohs paste treatment. Specifically, the size of the malignant wounds, and the number of times the dressing gauze required changing, significantly decreased (p < 0.05 and p < 0.01, respectively). The open malignant skin wounds caused by mammary gland tumors disappeared in two cases. The Mohs paste has been shown to be a viable option for the palliative treatment in canine and feline malignant skin wound management.

Intraoperative acridine orange photodynamic therapy and cribriform electron-beam irradiation for canine intranasal tumors: A pilot study.

Untreated canine intranasal tumors carry a poor prognosis. We retrospectively evaluated the efficacy of marginal tumor resection in combination with intraoperative acridine orange (AO) photodynamic therapy (PDT) and 1 fraction of 5 Gy megavoltage irradiation for canine intranasal malignant tumors. When cribriform plate invasion or turbinate destruction around the cribriform plate was present, an additional fraction of 20 Gy was delivered with an electron beam during surgery. The study included 6 dogs, 2 of which were classified as stage I, 1 as stage II, and 3 as stage IV. The median local disease-free survival time and overall survival after the treatment were 8.5 and 13 months, respectively. Recurrence was noted in 2 of the 6 dogs after 4 and 7 months. Adverse events were mild (subcutaneous emphysema in 1 case, and rhinitis in 3 cases). Combination AO therapy may increase the tumor control time of dogs with marginally resectable intranasal malignant tumors.

Pour des tumeurs intra-nasales malignes, une thérapie photodynamique administrant de l'acridine orange pendant l'opération et une irradiation par mégavoltage aux plaques cribriforms: l'etude préliminaire. Le pronostic des tumeurs intra-nasales canines non traitées est défavorable. Cette étude avait pour objectif d'évaluer rétrospectivement l'efficacité de la résection marginale d'une tumeur associée à une thérapie photodynamique (TPD) administrant de l'acridine orange (AO) pendant l'opération et à 1 fraction de 5 Gy d'irradiation par mégavoltage dans le traitement des tumeurs intra-nasales malignes. En cas d'invasion des plaques cribriformes et/ou de présence de cornets autour des lésions cribriformes, une fraction supplémentaire de 20 Gy a été administrée pendant l'opération par faisceaux d'électrons. Six chiens ont été inclus dans l'étude. Deux chiens présentaient des tumeurs de stade I, un de stade II et trois de stade IV. La durée moyenne de survie sans récidive locale et de survie globale après le traitement étaient respectivement de 8,5 et 13 mois. Une nouvelle tumeur est apparue chez deux des six chiens, respectivement 4 et 7 mois après le traitement. Les effets indésirables étaient bénins (un cas d'emphysème sous-cutané et trois cas de rhinite. L'association de la thérapie par AO améliorerait la durée de contrôle de la tumeur chez les chiens présentant des tumeurs intra-nasales malignes marginalement résécables.(Traduit par les auteurs).

Lipomatosis of the canine parotid gland: case report with a literature review.

In this report, we describe a case of lipomatosis in the left parotid gland of an eight-year-old female Shetland sheepdog and review the relevant literature. Preoperative diagnosis of lipomatosis with Tru-Cut biopsy presented difficulties in this case. The postoperative diagnosis was based on the gross appearance of a non-infiltrative, circumscribed swollen mass in the parotid gland and the histological appearance of normal adipocytes that infiltrated into the parotid gland without involving surrounding structures. Additionally, flotation of the whole parotid gland in formalin solution together with well-maintained residual lobulation and a well-maintained configuration on the cut surface were identified as subsidiary characteristics of lipomatosis of the parotid gland. Lipomatosis of the parotid gland has been rarely reported in dogs and is a poorly understood condition.

A NOVEL SUPPORT DEVICE FOR HEAD IMMOBILIZATION DURING RADIATION THERAPY THAT IS APPLICABLE TO BOTH CATS AND DOGS.

Repeatable head immobilization is important for minimizing positioning error during radiation therapy for veterinary patients with head neoplasms. The purpose of this retrospective cross-sectional study was to describe a novel technique for head immobilization (Device II) and compare this technique with a previously described technique (Device I). Device II provided additional support by incorporating three teeth (vs. two teeth with Device I). Between 2011 and 2013, both devices were applied in clinically affected cats (Device I, n = 17; Device II, n = 11) and dogs (Device I, n = 85; Device II, n = 22) of various breeds and sizes. The following data were recorded for each included patient: variability in the angle of the skull (roll, yaw, and pitch), coordinates of the isocenter, and distance from the reference mark to the tumor. Devices I and II differed for skull angle variability during the treatment of dogs (roll, P = 0.0007; yaw, P = 0.0018; pitch, P = 0.0384) and for yaw of during the treatment of cats (P < 0.0001). In each case, Device II was superior to Device I. The distance from the reference mark to the center of the tumor was significantly decreased for Device II vs. Device I (dogs, P < 0.0001; cats, P = 0.0002). Device II also provided more accurate coordinates for the isocenter. Authors recommend the use of, Device II for future clinical patients.

A case of cutaneous sterile pyogranuloma/granuloma syndrome in a maltese.

Cutaneous sterile pyogranuloma/granuloma syndrome (SPGS) is a locally restricted multinodular dermatitis. Affected dogs are typically healthy, but a few show systemic signs. Herein, a case of a dog presenting with generalized ulcerative dermatitis with systemic signs of mild anemia and an increased C-reactive protein level is described. Cutaneous SPGS was diagnosed by histopathology, negative staining causative organisms, and polymerase chain reaction for Mycobacterium spp. Successful treatment was achieved by immunosuppressive drugs, including prednisolone and azathioprine, administered for at least 20 mo. Recurrences of skin lesions were observed when prednisolone and/or azathioprine were discontinued. Long-term management with immunosuppressive agents may be required if the affected dog exhibits severe symptoms of cutaneous SPGS.

Dogs and humans share a common susceptibility gene SRBD1 for glaucoma risk.

Glaucoma is a degenerative optic neuropathy that is associated with elevated intraocular pressure. Primary open angle glaucoma is the most common type of glaucoma in canines, and its highest incidence among dog breeds has been reported in Shiba-Inus, followed by Shih-Tzus. These breeds are known to have an abnormal iridocorneal angle and dysplastic prectinate ligament. However, the hereditary and genetic backgrounds of these dogs have not yet been clarified. In this study, we investigated the association between polymorphisms of the glaucoma candidate genes, SRBD1, ELOVL5, and ADAMTS10, and glaucoma in Shiba-Inus and Shih-Tzus. We analyzed 11 polymorphisms in these three genes using direct DNA sequencing. Three SRBD1 SNPs, rs8655283, rs22018514 and rs22018513 were significantly associated with glaucoma in Shiba-Inus, while rs22018513, a synonymous SNP in exon 4, showed the strongest association (P = 0.00039, OR = 3.03). Conditional analysis revealed that rs22018513 could account for most of the association of these SNPs with glaucoma in Shiba-Inus. In Shih-Tzus, only rs9172407 in the SRBD1 intron 1 was significantly associated with glaucoma (P = 0.0014, OR = 5.25). There were no significant associations between the ELOVL5 or ADAMTS10 polymorphisms and glaucoma in Shiba-Inus and Shih-Tzus. The results showed that SRBD1 polymorphisms play an important role in glaucoma pathology in both Shiba-Inus and Shih-Tzus. SRBD1 polymorphisms have also been associated with normal- and high-tension glaucomas in humans. Therefore, SRBD1 may be a common susceptibility gene for glaucoma in humans and dogs. We anticipate that the nucleotide sequencing data from this study can be used in genetic testing to determine for the first time, the genetic status and susceptibility of glaucoma in dogs, with high precision. Moreover, canine glaucoma resulting from SRBD1 polymorphisms could be a useful animal model to study human glaucoma.

Validation of new bite block-type head-immobilization devices for radiotherapy in dogs.

An ideal head-immobilization method provides a high level of accuracy and reproducibility in the immobilization. Various head-immobilization methods for radiotherapy have been published and are excellent in terms of accuracy; however, these methods are complicated to use, and labor intensive. The present study describes two new bite block-type head-immobilization devices designed for higher stability and lower vertical variation. The device designed in our previous study (the bite block-type head-immobilization device; Device A) was modified by making a groove on the top the horizontal plate (Device B) for a stable ventral-dorsal position, or beneath the horizontal plate (Device C) for a stable dorsal-ventral position. The three devices were objectively compared with respect to setup time, and accuracy of the computed tomography scan images by two authors independently. Five male healthy beagles were used in this study. For each device, the setup time and the variation in the coordinates were measured five times for each dog. The mean setup times for Devices A, B, and C were 3.3, 1.5, and 2.4 min, respectively, showing the groove modifications were able to reduce the setup time (in device B, by at least 50%). Moreover, three-dimensional analysis of the computed tomography images revealed that the measurement variability of Device A (1.6 ± 1.0 mm) was significantly higher than that of Device C (0.7 ± 0.4 mm; P < 0.001). Collectively, our results show that use of a bite block-type head-immobilization device with a groove improves the setup time and head-immobilization accuracy.

Identification of cell surface antigen expression in canine hepatocellular carcinoma cell lines.

The characteristics of surface antigens in canine hepatocellular carcinoma (cHCC) have not been clarified. The objective of this study was to investigate surface antigens, which are considered as stem/progenitor or cancer cell markers, in cHCC cell lines. Expression of various antigens including CD29, CD34, CD44, CD90, CD133 and Dlk-1 was assessed in four cHCC cell lines by flow cytometry. CD44, CD133 and Dlk-1 expression was detectable in all cell lines, and three cell lines expressed CD29. These results indicate that CD29, CD44, CD133 and Dlk-1 have potential as suitable markers in cHCC identification, suggesting that these findings will contribute to the establishment of an early diagnostic tool for the identification of hepatocellular maturation processes.

Potential immunological adjuvant of `K'-type CpG-oligodeoxynucleotides enhanced the cell proliferation and IL-6 mRNA transcription in canine B cells.

CpG oligodeoxynucleotides (CpG-ODNs) are ligands for toll-like receptor 9 (TLR9), signaling of which plays a role in innate immunity by inducing T helper 1 (TH1)-cell responses and pro-inflammatory cytokine production. The activation of TLR9 signaling is considered to be effective for the therapy of cancer, infectious diseases, and allergies and preclinical studies using CpG-ODNs have been performed in dogs and humans. In order to investigate the precise mechanisms responsible for the effect of CpG-ODNs in dogs, we examined their role in cell proliferation and cytokine gene expression in canine B cells. Canine B cells were collected by a magnetic cell isolation method using anti-CD21 antibody. Flow cytometric analysis for the intracellular CD79α revealed the purity of canine B cells to be as high as 90.2 ± 2.1%. Transcription of TLR2, TLR4, and TLR9 mRNA on canine CD21(+) cells was confirmed by reverse-transcript polymerase chain reaction (RT-PCR). CpG-ODNs induced dose-dependent proliferation of canine CD21(+) cells (P<0.05 compared with control-ODNs) detected by BrdU incorporation. Quantification of IL-6, IL-10, and IL-12p40 mRNA transcription on canine CD21(+) cells revealed that CpG-ODNs enhanced IL-6 mRNA transcription but not IL-10 and IL-12p40 mRNA transcription (P<0.05 compared with control-ODNs). These responses to CpG-ODNs in the canine B cells indicated that CpG-ODNs would be useful as an immunological adjuvant for vaccine in dogs.

Cultivation and characterization of canine skin-derived mast cells.

It is essential to develop a technique to culture purified skin-derived mast cells (SMCs) to facilitate immunological research on allergic diseases in dogs. This study was performed to develop an efficient culture system for canine SMCs and to characterize the cells in comparison to canine bone marrow-derived mast cells (BMMCs). Enzymatically digested skin biopsy samples were cultivated in serum-free AIM-V medium supplemented with recombinant canine stem cell factor. Three to five weeks after the initiation of culture, mast cells were collected by a magnetic activated cell separation system using anti-c-Kit antibody. The collected cells were composed of a uniform population showing morphological characteristics of mast cells with a round or oval nucleus and abundant toluidine blue-positive metachromatic granules in the cytoplasm. The results of flow cytometric analysis for the presence of cell membrane c-Kit and Fc epsilon receptor I (FcepsilonRI) indicated that approximately 90% of the cells were mast cells. The cytoplasmic granules were positive for both tryptase and chymase. Apparent dose-dependent degranulation was induced by antibody-mediated cross-linking of immunoglobulin E (IgE) bound to the cells. These cytological and immunological characteristics observed in SMCs were mostly similar to those observed in BMMCs; however, IgE-mediated degranulation was significantly lower in SMCs than BMMCs. The culture system for canine SMCs developed in this study would be useful in understanding the pathophysiology and developing anti-allergic therapeutics in canine allergic dermatitis.

Identification of c-kit mutations-independent neoplastic cell proliferation of canine mast cells.

Gain-of-function mutations in the proto-oncogene c-kit have been considered the molecular mechanism of neoplastic proliferation of mast cells. However, the importance of c-kit gene mutations is not well evaluated in canine mast cell tumors (MCTs). In the present study, we established and characterized a mast cell line, HRMC, derived from a dog with MCT. We also examined c-kit mutations in HRMC cells and assessed an inhibitory effect of a tyrosine kinase inhibitor, STI571, on HRMC cells. HRMC cells had cytoplasmic metachromatic granules, chymase and tryptase, and expressed both KIT and FcepsilonRI on the cell surface. HRMC cells contained histamine and released beta-hexosaminidase through FcepsilonRI cross-linking and calcium ionophore stimulation. Nucleotide sequence analysis demonstrated no mutations in an open reading frame of c-kit cDNA and genomic DNA of the juxtamembrane domain of c-kit in HRMC cells. STI571 did not show any inhibitory effects on the proliferation of HRMC cells. These findings clearly demonstrated the existence of c-kit mutations-independent neoplastic canine mast cell proliferation. The growth factor-independent mast cell line established in this study might be valuable to explore novel mechanisms of c-kit mutations-independent neoplastic proliferation of mast cells in dogs.