Unusual Myoid Differentiation in a Canine Benign Mixed Mammary Tumour.

This report describes an unusual mesenchymal differentiation in a canine benign mixed mammary tumour. A 13-year-old crossbreed female dog was submitted to surgery to remove an inguinal mammary nodule. The tumour was composed of mammary epithelium and mesenchymal populations, not only of cartilage and bone but also of myoid cells. PTAH demonstrated cross striation of striated muscle, and immunohistochemistry highlighted striated muscle expressing desmin and calponin, and smooth muscle expressing desmin, SMA, and calponin. The tumour was diagnosed as a benign mixed tumour with leio- and rhabdomyoid differentiation. There was no tumour recurrence after one year of clinical follow-up. In conclusion, the well-differentiated features of leiomyocytes and rhabdomyocytes and the growth pattern define the benign origin of the mesenchymal component, which has been confirmed by a benign outcome; therefore, the knowledge of this kind of differentiation is helpful to avoid misdiagnoses.

Clinical Trypanosoma cruzi Disease after Cardiac Transplantation in a Cynomolgus Macaque (Macaca fascicularis).

A cynomolgus macaque received a heterotopic cardiac allograft as part of a transplant study, with monoclonal antibodies targeted to specific immune costimulation molecules (CD154, CD28) but no traditional immunosuppressive therapy after surgery. Clinical anemia was detected on postoperative day (POD) 35 and had worsened (Hgb, 2.3 g/dL; Hct = 7.3%) by POD 47, despite type-matched whole-blood transfusions. After a total of 4 blood transfusions, hematologic parameters were improved (Hgb, 5.9 g/dL; Hct, 18.7%). On POD 50, a peripheral blood smear revealed trypomastigotes, and qualitative RT-PCR of whole blood identified the organism as Trypanosoma cruzi. Although clinically stable initially, the macaque soon developed sufficient weight loss to necessitate euthanasia on POD 64. The final diagnosis was clinical anemia due to T. cruzi infection. This study represents the first reported case of Chagas disease after heart transplant in a NHP.

A peptide antagonist of CD28 signaling attenuates toxic shock and necrotizing soft-tissue infection induced by Streptococcus pyogenes.

Staphylococcus aureus and group A Streptococcus pyogenes (GAS) express superantigen (SAg) exotoxin proteins capable of inducing lethal shock. To induce toxicity, SAgs must bind not only to the major histocompatibility complex II molecule of antigen-presenting cells and the variable ß chain of the T-cell receptor but also to the dimer interface of the T-cell costimulatory receptor CD28. Here, we show that the CD28-mimetic peptide AB103 (originally designated "p2TA") protects mice from lethal challenge with streptococcal exotoxin A, as well as from lethal GAS bacterial infection in a murine model of necrotizing soft-tissue infection. Administration of a single dose of AB103 increased survival when given up to 5 hours after infection, reduced inflammatory cytokine expression and bacterial burden at the site of infection, and improved muscle inflammation in a dose-dependent manner, without compromising cellular and humoral immunity. Thus, AB103 merits further investigation as a potential therapeutic in SAg-mediated necrotizing soft-tissue infection.

Protective effect of inositol hexaphosphate against UVB damage in HaCaT cells and skin carcinogenesis in SKH1 hairless mice.

UVB radiation damages keratinocytes, potentially inducing chronic skin damage, cutaneous malignancy, and suppression of the immune system. Naturally occurring agents have been considered for prevention and treatment of various kinds of cancer, including skin cancer. Inositol hexaphosphate (IP6), an antioxidant, is a naturally occurring polyphosphorylated carbohydrate that has shown a strong anticancer activity in several experimental models. We assessed the protective effects of IP6 against UVB irradiationinduced injury and photocarcinogenesis by using HaCaT cells (human immortalized keratinocytes) and SKH1 hairless mice. We found that IP6 counteracts the harmful effects of UVB irradiation and increases the viability and survival of UVB-exposed cells. Treatment with IP6 after UVB irradiation (30 mJ/cm(2)) arrested cells in the G(1) and G(2) M phases while decreasing the S phase of the cell cycle. Treatment with IP6 also decreased UVB-induced apoptosis and caspase 3 activation. Topical application of IP6 followed by exposure to UVB irradiation in SKH1 hairless mice decreased tumor incidence and multiplicity as compared with control mice. Our results suggest that IP6 protects HaCaT cells from UVB-induced apoptosis and mice from UVB-induced tumors.

Expression of neuroimmune semaphorins 4A and 4D and their receptors in the lung is enhanced by allergen and vascular endothelial growth factor.

BACKGROUND: Semaphorins were originally identified as molecules regulating a functional activity of axons in the nervous system. Sema4A and Sema4D were the first semaphorins found to be expressed on immune cells and were termed "immune semaphorins". It is known that Sema4A and Sema4D bind Tim-2 and CD72 expressed on leukocytes and PlexinD1 and B1 present on non-immune cells. These neuroimmune semaphorins and their receptors have been shown to play critical roles in many physiological and pathological processes including neuronal development, immune response regulation, cancer, autoimmune, cardiovascular, renal, and infectious diseases. However, the expression and regulation of Sema4A, Sema4D, and their receptors in normal and allergic lungs is undefined. RESULTS: Allergen treatment and lung-specific vascular endothelial growth factor (VEGF) expression induced asthma-like pathologies in the murine lungs. These experimental models of allergic airway inflammation were used for the expression analysis of immune semaphorins and their receptors employing immunohistochemistry and flow cytometry techniques. We found that besides accessory-like cells, Sema4A was also detected on bronchial epithelial and smooth muscle cells, whereas Sema4D expression was high on immune cells such as T and B lymphocytes. Surprisingly, under inflammation various cell types including macrophages, lymphocytes, and granulocytes in the lung expressed Tim-2, a previously defined marker for Th2 cells. CD72 was found on lung immune, inflammatory, and epithelial cells. Bronchial epithelial cells were positive for both plexins, whereas some endothelial cells selectively expressed Plexin D1. Plexin B1 expression was also detected on lung DC. Both allergen and VEGF upregulated the expression of neuroimmune semaphorins and their receptors in the lung tissue. However, the lung tissue Sema4A-Tim2 expression was rather weak, whereas Sema4D-CD72 ligand-receptor pair was vastly upregulated by allergen. Soluble Sema4D protein was present in the lung lysates and a whole Sema4A protein plus its dimer were readily detected in the bronchoalveolar (BAL) fluids under inflammation. CONCLUSIONS: This study clearly shows that neuroimmune semaphorins Sema4A and Sema4D and their receptors might serve as potential markers for the allergic airway inflammatory diseases. Our current findings pave the way for further investigations of the role of immune semaphorins in inflammation and their use as potential therapeutic targets for the inflammatory lung conditions.

STAT6 expression in multiple cell types mediates the cooperative development of allergic airway disease.

Th2 cells induce asthma through the secretion of cytokines. Two such cytokines, IL-4 and IL-13, are critical mediators of many features of this disease. They both share a common receptor subunit, IL-4Rα, and signal through the STAT6 pathway. STAT6(-/-) mice have impaired Th2 differentiation and reduced airway response to allergen. Transferred Th2 cells were not able to elicit eosinophilia in response to OVA in STAT6(-/-) mice. To clarify the role of STAT6 in allergic airway inflammation, we generated mouse bone marrow (BM) chimeras. We observed little to no eosinophilia in OVA-treated STAT6(-/-) mice even when STAT6(+/+) BM or Th2 cells were provided. However, when Th2 cells were transferred to STAT6×Rag2(-/-) mice, we observed an eosinophilic response to OVA. Nevertheless, the expression of STAT6 on either BM-derived cells or lung resident cells enhanced the severity of OVA-induced eosinophilia. Moreover, when both the BM donor and recipient lacked lymphocytes, transferred Th2 cells were sufficient to induce the level of eosinophilia comparable with that of wild-type (WT) mice. The expression of STAT6 in BM-derived cells was more critical for the enhanced eosinophilic response. Furthermore, we found a significantly higher number of CD4(+)CD25(+)Foxp3(+) T cells (regulatory T cells [Tregs]) in PBS- and OVA-treated STAT6(-/-) mouse lungs compared with that in WT animals suggesting that STAT6 limits both naturally occurring and Ag-induced Tregs. Tregs obtained from either WT or STAT6(-/-) mice were equally efficient in suppressing CD4(+) T cell proliferation in vitro. Taken together, our studies demonstrate multiple STAT6-dependent and -independent features of allergic inflammation, which may impact treatments targeting STAT6.

Effect of magnetic fields on tumor growth and viability.

Breast cancer is the most common nonskin cancer and is the second leading cause of cancer-related deaths in women. Most methods of intervention involve combinations of surgery, chemotherapy, and ionizing radiation. Both chemotherapy and ionizing radiation can be effective against many types of cancer, but they also harm normal tissues. The use of nonionizing, magnetic fields has shown early promise in a number of in vitro and animal studies. Our study tested the effect of varying durations of magnetic exposure on tumor growth and viability in mice injected with breast cancer cells. Cancer cells were labeled through stable expression of firefly luciferase for monitoring of tumor growth and progression by using an in vivo imaging system. We hypothesized that magnetic field exposure would influence tumor growth and progression. Our results showed that exposure of the mice to magnetic fields for 360 min daily for as long as 4 wk suppressed tumor growth. Our study is unique in that it uses an in vivo imaging system to monitor the growth and progression of tumors in real time in individual mice. Our findings support further exploration of the potential of magnetic fields in cancer therapeutics, either as adjunct or primary therapy.

A protein-based smallpox vaccine protects non-human primates from a lethal monkeypox virus challenge.

Concerns about infections caused by orthopoxviruses, such as variola and monkeypox viruses, drive ongoing efforts to develop novel smallpox vaccines that are both effective and safe to use in diverse populations. A subunit smallpox vaccine comprising vaccinia virus membrane proteins A33, B5, L1, A27 and aluminum hydroxide (alum) ± CpG was administered to non-human primates, which were subsequently challenged with a lethal intravenous dose of monkeypox virus. Alum adjuvanted vaccines provided only partial protection but the addition of CpG provided full protection that was associated with a more homogeneous antibody response and stronger IgG1 responses. These results indicate that it is feasible to develop a highly effective subunit vaccine against orthopoxvirus infections as a safer alternative to live vaccinia virus vaccination.

Effect of inositol hexaphosphate on the development of UVB-induced skin tumors in SKH1 hairless mice.

Inositol hexaphosphate (IP6) is a naturally occurring polyphosphorylated carbohydrate that is abundant in many plants and in various high-fiber foods, such as cereals and legumes. IP6 has a striking, broad-spectrum anticancer activity in various in vitro and animal models, in which it interferes with key pathways in malignancy to inhibit cell proliferation, cell-cycle progression, metastasis, invasion, and angiogenesis and to induce apoptosis. In this study, we investigated the protective effects of IP6 in drinking water on the incidence of UVB-induced skin cancer in the SKH1 (Crl: SKH1-hr) mouse model. One group of 15 mice received 2% IP6 in drinking water and UVB exposure, and the other group (n = 15) received UVB exposure only. All mice in both groups were fed an IP6-deficient diet (AIN 76A). The treatment group started receiving 2% IP6 in the drinking water 3 d before irradiation. Mice were irradiated 3 times each week, starting at a dose of 1.5 kJ/m2, with weekly increases in increments of 1.5 kJ/m2 to a final dose of 7.5 kJ/m2. Tumor formation was monitored until the week 31. IP6 in drinking water significantly decreased tumor incidence by 5-fold and tumor multiplicity by 4-fold. These results show that IP6 has an antiphotocarcinogenic effect and can protect against UVB-induced tumor formation.

Mice deficient in the CXCR2 ligand, CXCL1 (KC/GRO-alpha), exhibit increased susceptibility to dextran sodium sulfate (DSS)-induced colitis.

The role of TLRs and MyD88 in the maintenance of gut integrity in response to dextran sodium sulfate (DSS)-induced colitis was demonstrated recently and led to the conclusion that the innate immune response to luminal commensal flora provides necessary signals that facilitate epithelial repair and permits a return to homeostasis after colonic injury. In this report, we demonstrate that a deficit in a single neutrophil chemokine, CXCL1/KC, also results in a greatly exaggerated response to DSS. Mice with a targeted mutation in the gene that encodes this chemokine responded to 2.5% DSS in their drinking water with significant weight loss, bloody stools, and a complete loss of gut integrity in the proximal and distal colon, accompanied by a predominantly mononuclear infiltrate, with few detectable neutrophils. In contrast, CXCL1/KC(- /-) and wild-type C57BL/6J mice provided water showed no signs of inflammation and, at this concentration of DSS, wild-type mice showed only minimal histopathology, but significantly more infiltrating neutrophils. This finding implies that neutrophil infiltration induced by CXCL1/KC is an essential component of the intestinal response to inflammatory stimuli as well as the ability of the intestine to restore mucosal barrier integrity.

Methicillin-resistant Staphylococcus non-aureus infection in an irradiated rhesus macaque (Macaca mulatta).

We describe a case of methicillin-resistant Staphylococcus non-aureus infection in a rhesus macaque (Macaca mulatta). The nonhuman primate described was part of a research project that involved whole-body gamma irradiation and subsequently developed acute generalized dermatitis with skin dryness, peeling, and erythema around the eyes. After initial evaluation, which included microbiologic culture and 6 d of medical treatment, the animal was euthanized due to concern regarding a possible outbreak of infectious or zoonotic disease. On the basis of skin culture, diagnosis of methicillin-resistant Staphylococcus non-aureus was confirmed. This report underscores the importance of the occupational risk of methicillin-resistant Staphylococcus non-aureus to research and animal care staff in a research animal facility setting.

A heterotopic primate model for facial composite tissue transplantation.

The purpose of this study was to develop a nonhuman primate model for heterotopic composite tissue facial transplantation in which to study the natural history of facial transplantation and evaluate immunosuppressive regimens.A composite oromandibular facial segment transplant based on the common carotid artery was evaluated. Flaps from 7 cynomolgus monkeys were transplanted to the groins of 7 recipients at the superficial femoral artery and vein. The immunosuppressive regimen consisted of thymoglobulin, rapamycin, and tacrolimus. Allograft survival ranged from 6 to 129 days. Histology performed in the long-term survivor at the time of necropsy revealed extensive inflammation and necrosis of the allograft skin; however, muscle and bone elements were viable, with minimal inflammation. This heterotopic facial transplantation model avoids the potential morbidity of mandibular resection and orthotopic facial transplantation. Our work also concurs with the work of other groups who found that the skin component is the most antigenic.

Mammary ductal carcinoma with comedo pattern in a rhesus macaque.

A 23-year-old female rhesus macaque presented with a 2.5-cm diameter, firm, moveable, lobulated subcutaneous mass associated with a supranummary teat on the right side of the chest. This animal was a retired breeder, currently in an aging study. No exogenous hormone treatments were noted in the animal's history. Chest radiographs were within normal limits. Blood screens showed no noteworthy variations from normal. Needle aspirate cytology showed clusters of neoplastic cells. Grossly the mass was well circumscribed, firm, and homogeneously tan, with a glandular appearance. Differential diagnoses included sebaceous or mammary adenoma, carcinoma in situ, and lobular or ductular carcinoma. Histopathology was consistent with a mammary ductal carcinoma with comedo pattern. Subsequent needle aspirate cytology from an adjacent right axillary lymph node showed tumor cells with a few lymphoid cells, interpreted as lymphatic spread. Chest radiographs 2 and 6 weeks postbiopsy showed no evidence of pulmonary metastasis. After 1 year, there was no marked change on chest radiographs, but a small cluster of new nodules was palpable in the right axillary region. Histopathology of an excisional biopsy of the new nodules indicated tumor growth subjacent to regional lymph nodes. Further treatment was not performed and the animal remained clinically normal five years after the initial diagnosis. Spontaneous mammary neoplasia is a major concern in human medicine, yet it rarely has been reported to occur in nonhuman primates. This case is important in documenting an additional case of spontaneous mammary tumor development.