Report of wood decay fungus Inonotus tropicalis (phylum Basidiomycota) from a dog with a granulomatous mediastinal mass.

A 75.9-kg, 3.5-year-old male Irish Wolfhound dog with a 2-3-week history of gagging and eating difficulties was referred to the University of Florida Veterinary Medical Hospital (Gainesville, Florida) for evaluation of a large cranial mediastinal mass suspected to be a thymoma or lymphosarcoma. The patient had 4 months of nearly 10 kg progressive weight loss with severe flank sensitivity and radiographically apparent lumbar vertebral changes interpreted as discospondylitis. Lab work revealed hyperglobulinemia, mild proteinuria, normal T4, negative Brucella canis titer, and negative blood and urine bacterial cultures. A thoracotomy revealed a nonresectable, destructive, space-occupying mediastinal mass resulting in euthanasia without surgical recovery. Biopsies from the mass were collected during surgery for histology. Microscopic examination revealed extensive granulomatous cellulitis and lymphadenitis characterized by central cavitated necrotic areas containing debris and degenerate neutrophils, intermediate zones of fibrovascular proliferation with marked mixed inflammation, peripheral fibrosis, frequent multinucleated macrophages, and scattered mineralization. The necrotic material contained dense mats of 2 µm wide by 8-15 µm long fungal hyphae with parallel walls, acute angle branching, frequent septae, and occasional bulb-like dilations. DNA sequencing and phylogenetic analysis of the internal transcribed spacer region confirmed the presence of a fungus in the Inonotus tropicalis group. Inonotus tropicalis is primarily a wood decay fungus that is found on dead wood from angiosperms in tropical and subtropical habitats. Isolates of the I. tropicalis group have been detected a few times from immunosuppressed human beings with X-linked granulomatous disease.

Gastrointestinal small-cell lymphoma with gall bladder involvement in a cat.

A 13-year-old female spayed domestic shorthair cat presented for investigation of decreased appetite and increased serum liver enzyme concentrations. An abdominal ultrasound revealed multiple sessile hyperechoic structures along the luminal aspect of the gall bladder wall and a mildly enlarged liver with hyperechoic nodules. Cholecystectomy was performed and biopsies were obtained by laparotomy. Histopathologic examination with immunohistochemistry was consistent with a diagnosis of small-cell lymphoma of T cells within the gall bladder, liver and small intestine. Clonality testing confirmed the diagnosis. The cat remains clinically stable 23 months after institution of treatment with prednisolone, chlorambucil and ursodeoxycholic acid. This is the first report of small-cell lymphoma in the gall bladder of a cat.

Excision of a congenital laryngeal cyst in a five-month-old dog via a lateral extraluminal approach.

CASE DESCRIPTION: A 5-month-old neutered male Golden Retriever was evaluated because of moderate stridor, exercise intolerance, and dyspnea. The dog had been neutered 3 weeks previously, and the referring veterinarian identified a large fluid-filled swelling on the left lateral aspect of the larynx during anesthetic intubation for that surgery. The referring veterinarian drained fluid from the mass by use of needle centesis via the oral cavity, which resulted in temporary improvement in clinical signs; however, the clinical signs returned soon thereafter. CLINICAL FINDINGS: A large, soft, spherical mass was located between the left arytenoid and thyroid cartilages and axial to the left ceratohyoid bone, thus causing partial obstruction of the rima glottidis. Laryngoscopic examination, computed tomography (CT), and cytologic evaluation of aspirates performed before surgery; examination during surgery; and histologic evaluation of tissues following surgical excision confirmed the diagnosis of a laryngeal cyst. TREATMENT AND OUTCOME: Complete surgical excision was successfully performed via a lateral extraluminal approach to the larynx. One week after surgery, the dog coughed only occasionally. Twelve months after surgery, the owner reported that the dog was clinically normal with no recurrence of clinical signs, and laryngoscopic examination revealed no recurrence of the cyst or other pathological changes in the laryngeal region. CLINICAL RELEVANCE: Congenital laryngeal cysts are rarely reported in domestic animals. The information provided here described the CT appearance of a laryngeal cyst and the use of CT in diagnosis and surgical planning. Congenital laryngeal cysts can be resected via a lateral submucosal approach.

Characterization of (2R, 3S)-2-([[4-(2-butynyloxy)phenyl]sulfonyl]amino)-N,3-dihydroxybutanamide, a potent and selective inhibitor of TNF-alpha converting enzyme.

TNF-alpha converting enzyme (TACE) is a validated therapeutic target for the development of oral tumor necrosis factor-alpha (TNF-alpha) inhibitors. Here we report the pre-clinical results and characterization of a selective and potent TACE inhibitor, (2R, 3S)-2-([[4-(2-butynyloxy)phenyl]sulfonyl]amino)-N,3-dihydroxybutanamide (TMI-2), in various in vitro and in vivo assays. TMI-2 is a potent TACE inhibitor in an enzymatic FRET assay (IC50=2 nM). It is more than 250-fold selective over MMP-1, -7, -9, -14, and ADAM-10 in vitro. In cell-based assays and human whole blood, TMI-2 inhibits lipopolysaccharide (LPS)-induced TNF secretion with IC50s<1 uM. Importantly, TMI-2 inhibits the spontaneous release of TNF-alpha in human synovium tissue explants of rheumatoid arthritis patients with an IC50 of 0.8 microM. In vivo, TMI-2 potently inhibits LPS-induced TNF-alpha production in mice (ED50=3 mg/kg). In the adjuvant-induced arthritis (AIA) model in rats, treatment with TMI-2 at 30 mg/kg and 100 mg/kg p.o. b.i.d. was highly effective in reducing joint arthritis scores. In a semi-therapeutic collagen-induced arthritis (CIA) model in mice, TMI-2 is highly effective in reducing disease severity scores after oral treatment at 100 mg/kg twice per day. In summary, TMI-2 is a potent and selective TACE inhibitor that inhibits TNF-alpha production and reduces the arthritis scores in pre-clinical models. TMI-2 represents a novel class of TACE inhibitors that may be effective and beneficial in the treatment of rheumatoid arthritis as well as other TNF-mediated inflammatory autoimmune diseases.

Helicobacter pylori infection and high dietary salt independently induce atrophic gastritis and intestinal metaplasia in commercially available outbred Mongolian gerbils.

Risk factors for development of gastric adenocarcinoma include high dietary salt and Helicobacter pylori infection. Few animal models exist for the laboratory investigation of these factors. We examined gastric pathology resulting from H. pylori infection and high dietary salt as independent variables in commercially available, outbred Mongolian gerbils. Gastric adenocarcinoma and its precursor lesion, intestinal metaplasia, have been previously reported in inbred Mongolian gerbils (MGS/Sea) infected either with clinical isolates of H. pylori or with the strain ATCC 43504. In contrast, we utilized outbred gerbils [Crl:(MON)] infected with the Sydney strain of H. pylori. After 37 weeks, five of five infected animals had atrophic gastritis and intestinal metaplasia. These lesions were similar in description and time of appearance to the lesions reported in inbred gerbils. Atrophic gastritis and intestinal metaplasia also developed in six of six uninfected, outbred gerbils fed a 2.5% salt diet for 56 weeks. In contrast to the H. pylori-infected animals, these lesions were present without concurrent gastric inflammation. The outbred Mongolian gerbil therefore provides an excellent animal model for the study of several gastric cancer risk factors.

Germ-line p53-targeted disruption inhibits helicobacter-induced premalignant lesions and invasive gastric carcinoma through down-regulation of Th1 proinflammatory responses.

p53 is a tumor suppressor gene that is mutated in many human malignancies, including gastric cancer. It remains unclear why patients with germ-line p53 mutations (i.e., Li-Fraumeni syndrome) are not at increased risk for gastric adenocarcinoma, despite the fact that they show a high rate of many other tumors. Furthermore, the precise relationship between germ-line p53 mutations and the response to chronic bacterial infections (such as Helicobacter spp.) has not been investigated. To assess the role of germ-line p53 deletions in modulating the progression to gastric cancer, p53(+/-) and wild-type (WT) C57BL/6 mice were infected with H. felis. The gastric pathology and immune response in these two groups of mice were analyzed for up to 15 months postinfection. The gastric fundus and antrum were evaluated independently using a 0-4 scale to score inflammation, parietal and chief cell loss, mucus metaplasia, and helicobacter colonization. Nonparametric statistical analysis was performed to determine the effects of p53(+/-), infection status, and postinoculation (p.i.) time on inflammation, preneoplastic changes, invasive lesions, and helicobacter colonization. mRNA expression for gammaIFN, interleukin (IL)-1, IL-10, and IL-4 was quantified by PCR. Sera were also evaluated for H. felis antibody by ELISA. Antral inflammation increased significantly with time in infected mice. There was a significant, protective effect on the development of preneoplastic fundic lesions and invasive carcinoma attributable to the deletion of one p53 allele (P < 0.05). Submucosal invasive foci were observed in 9 of 11 WT-infected mice ranging from 13 to 15 months p.i.; invasion of adjacent submucosal blood vessels by glandular epithelia also was present in 5 of these mice. None of these lesions were observed in 33 p53(+/-) mice, infected or not, at any time p.i. p53(+/-) mice had significantly higher helicobacter colonization consistent with a Th2 host response. In sera from WT mice, IgG2a, considered a proinflammatory Th1 response, continued to rise throughout the 15-month study (P < 0.004). In contrast, IgG2a levels of the p53(+/-) mice were 50-60% lower than those of the WT mice at each time point (P range, <0.012 to 0.002) and did not progress in magnitude between 12 and 15 months of chronic H. felis infection (P = 0.167). mRNA levels for gammaIFN and IL-1 were significantly up-regulated in WT mice infected with H. felis (P < 0.05) but were slightly elevated or were at background levels in p53(+/-) mice. IL-10 and IL-4 mRNA expression was not significantly different from control samples. Our results support the hypothesis that germ-line deletion of one p53 allele results in a down-regulated Th1 response to gastric helicobacter infection, possibly because of T-cell senescence, which may indirectly protect against the development of gastric cancer and other epithelial-derived neoplasms associated with chronic inflammation.