Reciprocal upregulation of Notch signaling molecules in hematopoietic progenitor and mesenchymal stromal cells

Although mesenchymal stem cells (MSCs) play pivotal supportive roles in hematopoiesis, how they interact with hematopoietic stem cells (HSCs) is not well understood. We investigated the interaction between HSCs and surrogate MSCs (C3H10T1/2 stromal cells), focusing on the molecular events induced by cell contact of these bipartite populations. C3H10T1/2 is a mesenchymal stromal cell line that can be induced to differentiate into preadipocytes (A54) and myoblasts (M1601). The stromal cell derivatives were cocultured with murine HSCs (Lineage(-)Sca1(+)), and gene expression profiles in stromal cells and HSCs were compared before and after the coculture. HSCs gave rise to cobblestone areas only on A54 cells, with ninefold more progenitors than on M1601 or undifferentiated C3H10T1/2 cells. Microarray-based screening and a quantitative reverse transcriptase directed-polymerase chain reaction showed that the levels of Notch ligands (Jagged1 and Delta-like 3) were increased in A54 cells upon interaction with HSCs. On the other hand, the expression of Notch1 and Hes1 was upregulated in the HSCs cocultured with A54 cells. A transwell assay revealed that the reciprocal upregulation was dependent on cell-to-cell contact. The result suggested that in the hematopoietic niche, HSCs help MSCs to produce Notch ligands, and in turn, MSCs help HSCs to express Notch receptor. Such a reciprocal upregulation would reinforce the downstream signaling to determine the fate of hematopoietic cell lineage. Clarification of the initiating events on cell contact should lead to the identification of specific molecular targets to facilitate HSC engraftment in transplantation therapy.

Hepatoblastoma in a cat

Hepatoblastomas are neoplasms that originate from putative pluripotential stem cells of the liver. A hepatic mass from an 8-year-old Abyssinian cat was composed of cords and sheets of neoplastic cells, with scattered rosettes and small ductal structures. Most neoplastic cells had a pale eosinophilic cytoplasm and a round to ovoid nucleus. The tumor also had short spindle cells with an oval nucleus. Immunohistochemically, neoplastic cells were weakly positive for embryonic hepatocellular markers, such as alpha-fetoprotein and cytokeratin (CK) 8/18, but negative for the hepatocellular marker Hepatocyte Paraffin 1. The cells were also positive for CD56/neural cell adhesion molecule and for the biliary epithelial markers CK 7, CK 8/18, CK CAM5.2, and vimentin, but negative for CK 20. Some neoplastic cells expressed neuroectodermal or neuroendocrine markers, such as protein gene product 9.5 and synaptophysin, but were negative for chromogranin A and not argyrophilic by the Grimelius technique. The cat died soon after the biopsy without clinical improvement.

Emperipolesis-like invasion of neoplastic lymphocytes into hepatocytes in feline T-cell lymphoma

Twelve cases of feline malignant lymphoma with emperipolesis-like invasion of neoplastic lymphocytes were examined microscopically, immunohistochemically and ultrastructurally. Intracytoplasmic invasion of neoplastic cells varied in severity between the cases, between hepatic lobules and between areas within the lobules. The number of infiltrating neoplastic cells ranged from one to several per hepatocyte. Neoplastic cells exhibited widely varying morphology from case-to-case and cell-to-cell within each case, and contained eosinophilic cytoplasmic granules in four cases. Immunohistochemical examination revealed that neoplastic cells in 11 of the 12 cases expressed one or both T-cell markers (CD3 and TIA-1). Diagnosis of T-cell lymphoma was also confirmed by assessment of clonality by polymerase chain reaction. Ultrastructural analysis revealed that the neoplastic lymphocytes were contained within an invagination of the cell membrane of the hepatocyte, rather than directly infiltrating into the cytoplasm of the cell. There was no evidence that the invasive neoplastic lymphocytes had a cytotoxic effect.

Dental caries and caries-related periodontitis in type 2 diabetic mice

Diabetic patients are predisposed to periodontal disease as well as dental caries; however, there are contradictory reports about the possible association between dental caries and diabetes. Thus, the authors set out to determine whether diabetes affects onset of dental caries and periodontal disease and to clarify whether dental caries and periodontal disease are associated with each other in diabetic db/db mice. Oral tissue was examined from 68 male mice (diabetic db/db and nondiabetic db/+; aged 20, 30, 40, and 50 weeks) and 20 female mice (db/db and db/+; aged 50 weeks). Macroscopically, caries were seen developing in the diabetic mice by 20 weeks of age. The number of teeth with dental lesions increased with age in the db/db mice at a significantly higher incidence than that of db/+ mice. Histologically, dental caries were detected in 30 of 120 molars in 17 of 20 db/db mice at 50 weeks of age and in 4 of 108 molars in 4 of 18 db/+ mice of the same age. The severity of dental caries in db/db mice was significantly higher than it was in db/+ mice. Dental caries were a primary change that led to bacterial gingivitis and pulpitis. These lesions spread to the dental root and periodontal connective tissue through the apical foramen. Apical periodontitis was more frequent and severe when occurring in close association with dental caries. In conclusion, there is a strong relationship between diabetes and dental caries, but in this model, it is highly probable that the onset of periodontal disease was a secondary change resulting from dental caries.

Proinflammatory effects of muramyldipeptide on human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Because human gingival fibroblasts (HGFs) are the predominant cells in periodontal tissues, we hypothesized that HGFs are contributed to receptors for components of bacteria. In this study, we focused on expression and function of nucleotide binding oligomerization domain 2 (NOD2) in HGFs, which is a mammalian cytosolic pathogen recognition molecule.

MATERIAL AND METHODS

Expression of NOD2 in HGFs was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry. Production of interleukin (IL)-6, IL-8, cc chemokine ligand2, cxc chemokine ligand10 (CXCL10) and CXCL11 from HGFs was examined by enzyme-linked immunosorbent assay (ELISA). We used RT-PCR and immunohistochemistry to detect the NOD2 expression in human gingival tissues.

RESULTS

We found clear NOD2 expression in HGFs. Upon stimulation with NOD2 agonist, muramyldipeptide (MDP), production of proinflammatory cytokines was enhanced. Moreover, MDP-induced production of proinflammatory cytokines was inhibited in a different manner by mitogen-activated protein kinase inhibitors and phosphatidylinositol 3-kinase inhibitor. Furthermore, MDP enhanced CXCL10 and CXCL11 productions by tumor necrosis factor-alpha (TNF-alpha)- or interferon-gamma (IFN-gamma)-stimulated HGFs, although MDP alone did not induce these chemokines. TNF-alpha and IFN-gamma increased NOD2 expression in HGFs. In addition, we detected NOD2 expression in mononuclear cells and HGFs in periodontally diseased tissues.

CONCLUSION

These findings indicate that MDP which induces production of cytokines and chemokines from HGFs is related to the pathogenesis of periodontal disease.

Stimulatory action of mitemcinal (GM-611), an acid-resistant non-peptide motilin receptor agonist, on colonic motor activity and defecation: spontaneous and mitemcinal-induced giant migrating contractions during defecation in dogs

The aim of this study was to characterize giant migrating contractions (GMCs) during spontaneous defecation in dogs and to investigate the effect of mitemcinal (an orally active and highly acid-resistant motilin receptor agonist) on colonic motility to assess the possibility of using it for the treatment of colonic motility disorders. To assess colonic motility, strain-gauge force transducers were implanted on the gastrointestinal tract of five dogs, and the behaviour of the dogs was monitored with a noctovision-video camera system. The effect of mitemcinal (0, 3, 10 or 30 mg per dog) and sennoside (300 mg per dog) on colonic motility was assessed 24 h after oral administration. During a 39-day period, the starting point of most of the 140 GMCs was between the transverse colon and the descending colon, but some variation was observed. In the daytime, the GMCs originated from somewhat more proximal positions than at night. Mitemcinal caused an increase in the GMC-index (integration of contractile amplitude and duration) and proximal translocation of the GMC starting point, but did not cause an increase in the number of defecations 12 h after administration. Sennoside, however, caused a significant increase in the number of defecations, an increase in the GMC-index, and prolongation of the duration of GMCs. The GMC starting point in the canine colon varied during spontaneous defecation. Mitemcinal was a potent prokinetic drug to mimic a spontaneous defecation compared with sennoside. Mitemcinal evacuates more intestinal luminal contents during the defecation than does sennoside.

IL-21 is critical for GVHD in a mouse model

Immunological effects of IL-21 on T, B and natural killer (NK) cells have been reported, but the role of IL-21 in GVHD remains obscure. Here, we demonstrate that morbidity and mortality of GVHD was significantly reduced after BMT with splenocytes from IL-21R(-/-) mice compared with those from wild type mice. To further confirm our observation, we generated a decoy receptor for IL-21. GVHD was again less severe in mice receiving BM cells transduced with the IL-21 decoy receptor than control mice These results suggest that IL-21 critically regulates GVHD, and that blockade of the IL-21 signal may represent a novel strategy for the prophylaxis for GVHD.

Human gingival fibroblasts express functional chemokine receptor CXCR6

We have reported that CXCL16, a recently discovered transmembrane chemokine, is expressed in human gingival fibroblasts (HGF). However, it is not known whether HGF express CXCR6, the receptor for CXCL16, or CXCL16 affects HGF biology. We have shown that HGF expressed CXCR6 by reverse transcription-polymerase chain reaction and flow cytometric analysis. Moreover, we elucidated that tumour necrosis factor (TNF)-alpha and cytosine-guanine dinucleotide (CpG) DNA (Toll-like receptor-9 ligand) treatment enhanced CXCR6 expression by HGF. Interleukin (IL)-4, IL-13 and CpG DNA up-regulated CXCR6 expression by TNF-alpha-stimulated HGF. On the other hand, IL-1beta and interferon-gamma inhibited CXCR6 expression on TNF-alpha-treated HGF. CXCL16 treatment induced HGF proliferation and phosphorylation of extracellular regulated kinase (ERK) and protein kinase B (AKT) in HGF. In conclusion, HGF expressed CXCR6 functionally, because CXCL16 induced HGF proliferation and ERK and AKT phosphorylation in HGF. These results indicate that CXCL16 may play an important role in the pathogenesis and remodelling in periodontally diseased tissues.

Thymoma in a Java sparrow (Padda oryzivora)

Thymoma is described in a 3-year-old female Java sparrow (Padda oryzivora). Histopathologically, the subcutaneous mass from the cervical region consisted of epithelial cells characterized by large polyhedral cells and spindle cells, which sometimes showed squamous differentiation, and small lymphocytes without apparent atypical forms. Immunohistochemically, the epithelial cells possessed cytokeratin in their cytoplasm and proliferating cell nuclear antigen.

CC chemokine ligand 17 in periodontal diseases: expression in diseased tissues and production by human gingival fibroblasts

BACKGROUND AND OBJECTIVE

It has been reported that T helper 2 (Th2) cells are related to exacerbation of periodontal disease. However, it is uncertain how the migration of Th2 cells is controlled. In this study, we examined the expression of CC chemokine ligand 17 (CCL17), which is a Th2 chemokine, in periodontal tissues. Moreover, we investigated the effects of cytokines and toll-like receptor (TLR) ligands on the production of CCL17 by human gingival fibroblasts (HGFs).

MATERIAL AND METHODS

We used immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) to detect CCL17 in periodontal tissues. HGFs were exposed to cytokines and TLR ligands. Expression of CCL17 was examined by RT-PCR and enzyme-linked immunosorbent assay. We used signal transduction inhibitors in some experiments.

RESULTS

Both CCL17 and its receptor, CC chemokine receptor 4 (CCR4), were expressed in diseased periodontal tissues. A combination of tumour necrosis factor alpha (TNF-alpha) and interleukin (IL)-4/IL-13 increased CCL17 expression. Moreover, treatment of HGFs with a low dose of interferon-gamma (IFN-gamma) in combination with TNF-alpha and IL-4 or IL-13 had synergistic effects on the production of CCL17, whereas a high dose of IFN-gamma inhibited CCL17 production. Furthermore, Escherichia coli (E. coli) lipopolysaccharide (TLR4 ligand) and Pam3CSK4 (TLR2 ligand) inhibited CCL17 production by TNF-alpha + IL-4-stimulated HGFs, while CpG DNA (TLR9 ligand) enhanced TNF-alpha + IL-4 induced-CCL17 production by HGFs. Furthermore, a c-Jun NH2 terminal kinase (JNK) inhibitor, a phosphatidylinositol-3-kinase (PI3K) inhibitor and a nuclear factor kappa B (NF-kappa B) inhibitor inhibited CCL17 production by HGFs.

CONCLUSION

These results suggest that the CCL17 produced by HGFs may be involved in the migration of Th2 cells into inflamed tissues, and provide evidence that CCL17 production is controlled by cytokines and TLR ligands in periodontal disease.

Nasal and paranasal adenocarcinomas with neuroendocrine differentiation in dogs

Tumors of the nasal cavity or paranasal sinuses of 18 dogs were examined histopathologically, immunohistochemically, and histochemically. The tumors were classified histologically as 13 adenocarcinomas, 3 transitional carcinomas, 1 squamous cell carcinoma, and 1 adenosquamous carcinoma. Tumor cells were strongly immunoreactive for broad-spectrum cytokeratins in all cases, for cytokeratin 8/18 in 16 cases, and for cytokeratin 19 in 17 cases. None of the 18 carcinomas had cytologic or histologic features indicative of neuroendocrine differentiation, yet tumor cells in 5 of the 13 adenocarcinomas were argyrophilic and immunohistochemically positive for synaptophysin and chromogranin A. Results of this study indicate that neuroendocrine markers may be detected immunohistochemically and histochemically in canine nasal or paranasal adenocarcinomas despite the lack of typical histologic features of neuroendocrine differentiation.

Adrenomedullin suppresses tumour necrosis factor alpha-induced CXC chemokine ligand 10 production by human gingival fibroblasts

Periodontal disease is an inflammatory disorder characterized by the involvement of chemokines that are important for the recruitment of leucocytes. Several cytokines, including tumour necrosis factor alpha (TNF-alpha), are involved in regulating levels of chemokines in periodontal disease. CXC chemokine ligand 10 (CXCL10) is a chemokine related to the migration of T helper 1 cells. In this study, we examined CXCL10 expression in human gingival fibroblasts (HGFs). Moreover, we investigated the effects of adrenomedullin (AM), which is a multi-functional regulatory peptide, on the production of CXCL10 by HGFs. We revealed that TNF-alpha stimulation induced CXCL10 production by HGFs. HGFs expressed AM and AM receptors, calcitonin-receptor-like receptor (CRLR) and receptor-activity-modifying protein (RAMP) 2, mRNAs constitutively. AM treatment supressed CXCL10 production by TNF-alpha-stimulated HGFs. Moreover, we elucidated that AM produced by HGFs inhibited CXCL10 production by HGFs, because AM antagonist enhanced CXCL10 production by HGFs. TNF-alpha treatment enhanced CRLR and RAMP2 mRNA expression in HGFs. Furthermore, AM is expressed in human periodontal tissues, including both inflamed and clinically healthy tissues. These results suggest that the CXCL10 produced by HGFs may be involved in the migration of leucocytes into inflamed tissues and related to exacerbation of periodontal disease. AM might be a therapeutic target of periodontal disease, because AM can inhibit CXCL10 production by HGFs.

Dandelion T-1 extract up-regulates reproductive hormone receptor expression in mice

Reproductive hormones exert their actions via receptors in diverse tissues. In this study, we examined the expression of estrogen receptors (ERalpha and ERbeta), progesterone receptor (PR), and follicle-stimulating hormone receptor (FSHR) in the adipose tissue and reproductive organs of mice following oral treatment with Dandelion T-1 extract (DT-1E) for 6 weeks. Quantitative assays by real-time reverse transcription polymerase chain reaction showed enhanced expression of ERalpha and ERbeta mRNA in the adipose tissue of mice fed a diet containing DT-1E compared with the control group fed a plain diet. Furthermore, following gonadotropin injection, higher mRNA expression of ERalpha, ERbeta and PR in the uterus and FSHR in the ovary was found in the DT-1E group compared with the control group. An immunohistochemical study also showed increased levels of the above-mentioned receptors in the DT-1E group. The present study shows that oral intake of DT-1E up-regulates ERalpha, ERbeta, PR and FSHR expression in mice, suggesting the potential application of DT-1E for the clinical treatment of reproductive hormone-related disturbances.

Identification of TSC-22 as a potential tumor suppressor that is upregulated by Flt3-D835V but not Flt3-ITD

Transforming growth factor-beta (TGF-beta)-stimulated clone-22 (TSC-22) was originally isolated as a TGF-beta-inducible gene. In this study, we identified TSC-22 as a potential leukemia suppressor. Two types of FMS-like tyrosine kinase-3 (Flt3) mutations are frequently found in acute myeloid leukemia: Flt3-ITD harboring an internal tandem duplication in the juxtamembrane domain associated with poor prognosis and Flt3-TKD harboring a point mutation in the kinase domain. Comparison of gene expression profiles between Flt3-ITD- and Flt3-TKD-transduced Ba/F3 cells revealed that constitutive activation of Flt3 by Flt3-TKD, but not Flt3-ITD, upregulated the expression of TSC-22. Importantly, treatment with an Flt3 inhibitor PKC412 or an Flt3 small interfering RNA decreased the expression level of TSC-22 in Flt3-TKD-transduced cells. Forced expression of TSC-22 suppressed the growth and accelerated the differentiation of several leukemia cell lines into monocytes, in particular, in combination with differentiation-inducing reagents. On the other hand, a dominant-negative form of TSC-22 accelerated the growth of Flt3-TKD-transduced 32Dcl.3 cells. Collectively, these results suggest that TSC-22 is a possible target of leukemia therapy.

In vitro effect of dehydroepiandrosterone sulfate on steroid receptors, aromatase, cyclooxygenase-2 expression, and steroid hormone production in preovulatory human granulosa cells

OBJECTIVE

To examine the effect of a low concentration of DHEAS on the expression of the androgen receptor, estrogen receptor alpha and beta, progesterone receptor, aromatase, 3-beta-hydroxysteroid dehydrogenase, and cyclooxygenase-2 in human preovulatory granulosa cells, and to measure their production of steroid hormones (estrone, estradiol, progesterone, androstenedione, and testosterone).

DESIGN

Analysis of cultured primary human preovulatory granulosa cells by real-time reverse-transcriptase polymerase chain reaction and assays of hormone production.

SETTING

Osaka City University Postgraduate School of Medicine.

INTERVENTION(S)

Preovulatory granulosa cells were collected from follicular fluid obtained from patients undergoing transvaginal oocyte retrieval with ultrasound guidance. The cells were cultured in the absence or presence of a low concentration of DHEAS. Real-time reverse-transcriptase polymerase chain reaction was performed to quantify the RNA expression of the investigated genes, and steroid hormone (estrone, estradiol, progesterone, androstenedione, and testosterone) levels were measured in the culture medium.

MAIN OUTCOME MEASURE(S)

Changes in [1] the levels of mRNAs encoding androgen receptor, estrogen receptor alpha, estrogen receptor beta, progesterone receptor, aromatase, 3-beta-hydroxysteroid dehydrogenase, and cyclooxygenase-2; and [2] the levels of steroid hormones (estrone, estradiol, progesterone, androstenedione, and testosterone) in the culture medium.

RESULT(S)

Treatment of granulosa cells with 20 ng/mL DHEAS increased the expression of androgen receptor, aromatase, 3-beta-hydroxysteroid dehydrogenase, and cyclooxygenase-2, reduced the expression of estrogen receptor beta, and increased estrone and estradiol levels, but had no effect on progesterone, androstenedione, or testosterone levels.

CONCLUSION(S)

DHEAS may be an essential trigger of ovulation.

Renal dysplasia unrelated to claudin-16 deficiency in Japanese Black cattle

Renal lesions of the type usually found in claudin-16 (CL-16) defective Japanese Black cattle (homozygous for CL-16 deficiency) were identified in six animals of this breed, aged 28-59 months, which were either heterozygous for CL-16 deficiency (type 1) or normal, as judged by a DNA-based test associated with the CL-16 gene. Histopathologically, all six cases showed elongated focal lesions which ran through the cortex to terminate in the outer zone of the medulla. The lesions contained components that included: (1) immature tubules, (2) small irregularly shaped tubules with thickening of the basement membrane, (3) mesenchymal cells in an increased interstitium, (4) small atrophic glomeruli, and (5) immature glomeruli. The glomeruli were noticeably reduced in number, and large glomeruli with an increased number of mesangial cells were observed throughout the entire cortical area. Cystic dilation of tubules and flattening of the epithelium were noted in all areas of the kidney. Histopathologically, the renal lesions in the six cases were indistinguishable from those reported previously in cattle homozygous for CL-16 deficiency. These findings demonstrate that such renal lesions in Japanese Black cattle are not necessarily associated with homozygous deletion of the CL-16 gene.

Initial response to immunosuppressive and renoprotective treatment in posttransplant glomerulonephritis

The current studies on posttransplant glomerulonephritis (PTxGN) do not establish when, how, or how long we must treat these patients. This study sought to compare the initial response to immunosuppressive treatment and renoprotection in PTxGN.

PATIENTS AND METHODS

This prospective study was performed in 23 patients with a histological diagnosis of PTxGN.

RESULTS

Mean follow-up was 12 months (3-18); 91% received immunosuppressants, and 56.5% just renoprotective drugs. The best results (reduction of serum creatinine [SCr] and proteinuria) with immunosuppression were observed in patients with recurrent membranous PTxGN using the scheme of Ponticelli (IV + PO corticosteroid [CS] + PO cyclophosphamide [CPP]). A similar response was also seen in subjects with recurrent or de novo focal glomerulosclerosis treated with PO CS or CPP, except when the initial SCr > 2.5 mg/dL. In de novo IgA nephropathy, reduction of proteinuria occurred with use of PO CS, with or without CPP, but without improvement in SCr. Patients with recurrent or de novo crescentic PTxGN used renoprotective drugs and always immunosuppressants. In this group, good results were seen with IV + PO CS, with or without CPP, when there was less than 50% of glomeruli with crescents, or more than 50% with crescents but an initial SCr < 2.5 mg/dL.

CONCLUSION

Immunosuppression seemed to give a better initial response than renoprotection in cases of membranous, IgA, and focal segmental glomulerulosclerosis PTxGN. Patients with an initial SCr > or = 2.5 mg/dL displayed worse outcomes.

CXC chemokine ligand 16 in periodontal diseases: expression in diseased tissues and production by cytokine-stimulated human gingival fibroblasts

Periodontal disease is an inflammatory disorder characterized by the involvement of chemokines that are important for the recruitment of leucocytes. Several cytokines are involved in regulating levels of chemokines in periodontal disease. CXCL16 is a chemokine related to the migration of T helper 1 (Th1) cells and natural killer (NK) cells. In this study, we examined its expression in periodontal tissues. Moreover, we investigated the effects of cytokines on the production of CXCL16 by human gingival fibroblast (HGF). Reverse transcription-polymerase chain reaction (RT-PCR) analysis and immunohistochemistry revealed that CXCL16 and its receptor, CXCR6, were expressed at the mRNA and protein levels in diseased tissues. Proinflammatory cytokines [interleukin (IL)-1beta, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma] increased the mRNA expression and release of CXCL16 in a dose-dependent manner. Moreover, treatment of HGFs with IFN-gamma in combination with IL-1beta had a synergistic effect on the production of CXCL16. On the other hand, IL-4 and IL-13 inhibited the IL-1beta-induced CXCL16 production by HGFs. Inhibitors of A disintegrin and metalloprotease (ADAM)10 and ADAM17, a recently identified protease of CXCL16, reduced the amount of CXCL16 released from HGFs. These results suggest that the CXCL16 produced by HGFs may be involved in the migration of leucocytes into inflamed tissues, and provide evidence that CXCL16 production is controlled by cytokines in periodontal disease.

Mitemcinal (GM-611), an orally active motilin agonist, facilitates defecation in rabbits and dogs without causing loose stools

The effects of mitemcinal (GM-611), an orally active motilin agonist, on defecation were investigated in rabbits and dogs. In normal rabbits, within 0-3 h of dosing, orally administered mitemcinal (2.5-10 mg kg(-1)) increased stool weight in a dose-dependent manner without causing loose stools. Sennoside (12-48 mg kg(-1)) also facilitated defecation within 2-9 h of oral administration, but the stools were significantly loosened. In the morphine-induced constipation model, the stool weight of morphine-treated rabbits (1 mg kg(-1)) was only 37.5% of that of untreated animals. Mitemcinal (0.5-20 mg kg(-1)) dose-dependently increased stool weight without increasing stool water content. At the highest dose of mitemcinal, stool weight recovered to 83.9% of that of untreated animals. In normal dogs, mitemcinal (0.3-3 mg kg(-1)) reduced the time to first bowel movement after oral administration without inducing diarrhoea at any dose. These results indicate that mitemcinal facilitates defecation without inducing severe diarrhoea. It is suggested that mitemcinal may be a novel therapeutic agent for constipation that enables easier control of the timing of defecation because of the early onset and short duration of its action, compared with sennoside.

Interferon-gamma and NF-kappaB mediate nitric oxide production by mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) have been shown to have an immunosuppressive effect. Previously, we demonstrated that nitric oxide (NO) is one of the immunomodulatory mediators of MSCs. We herein show that primary mouse bone marrow MSCs and three cell lines that mimic MSCs suppress both differentiation and proliferation in Th1 condition, whereas the suppression in Th2 condition is mild. NO production is inversely correlated with T cell proliferation in Th1 and Th2 conditions. NO is highly induced in Th1 and minimally induced in Th2. Moreover, an inhibitor of NO synthase restores both proliferation and interferon-gamma (IFN-gamma) production in Th1 condition. Furthermore, an anti-IFN-gamma antibody strongly inhibits NO production and an inhibitor of NF-kappaB reduces the level of induction of inducible NO synthase (iNOS) in MSCs. Taken together, our results suggest that NO plays a significant role in the modification of Th1 and Th2 differentiation by MSCs, and that both IFN-gamma and NF-kappaB are critical for NO production by MSCs.

Proinflammatory effects of tumour necrosis factor-like weak inducer of apoptosis (TWEAK) on human gingival fibroblasts

Tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK), a member of the TNF family, is a multi-functional cytokine that regulates cellular proliferation, angiogenesis, inflammation and apoptosis. In this study, we investigated TWEAK expression in periodontally diseased tissues and the effect of TWEAK on human gingival fibroblasts (HGF). Reverse transcription-polymerase chain reaction (RT-PCR) analysis and immunohistochemistry revealed that TWEAK and the TWEAK receptor, fibroblast growth factor-inducible 14 (Fn14), mRNA and protein were expressed in periodontally diseased tissues. HGF expressed Fn14 and produced interleukin (IL)-8 and vascular endothelial growth factor (VEGF) production upon TWEAK stimulation in a dose-dependent manner. The IL-8 and VEGF production induced by TWEAK was augmented synergistically by simultaneous stimulation with transforming growth factor (TGF)-beta1 or IL-1beta. IL-1beta and TGF-beta1 enhanced Fn14 expression in a dose-dependent manner. Moreover, TWEAK induced intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression on HGF in a dose-dependent manner. The ICAM-1 expression induced by TWEAK was augmented by TGF-beta1. On the other hand, the TWEAK-induced VCAM-1 expression was inhibited by TGF-beta1. Phosphatidylinositol 3-kinase (PI3K) and nuclear factor-kappaB (NF-kappaB) inhibitor inhibit both ICAM-1 and VCAM-1 expression induced by TWEAK. However, mitogen-activated protein kinase (MEK) and c-Jun NH2-terminal kinase (JNK) inhibitor enhanced only VCAM-1 expression on HGF. These results suggest that TWEAK may be involved in the pathophysiology of periodontal disease. Moreover, in combination with IL-1beta or TGF-beta1, TWEAK may be related to the exacerbation of periodontal disease to induce proinflammatory cytokines and adherent molecules by HGF.

Cardiac Vascular Hamartoma in Two Slaughtered Cattle

Two cases of cardiac vascular hamartoma were detected in slaughtered cattle. In each case, a single nodular protrusion (ca 2.5 cm in diameter) was located in the same part of the right atrium. Tortuous vessels of variable size with irregular lumina were seen on the cut surface of each nodule. Microscopically, there were many dysplastic vascular structures within the nodules. The vascular structures showed various changes such as irregular thickening of the tunica intima and the tunica media, walls with variable amounts of fibres (elastic, collagen and smooth muscle), some of which were disarranged. Mature adipose tissue and fibrous connective tissue were seen close to the vascular structures and intervascular tissue. In the nodules, bundles of cardiac muscle were disorganized, intermingled with connective tissue, and in some areas embedded within fibrous connective tissue.

Mitemcinal (GM-611), an orally active motilin receptor agonist, accelerates colonic motility and bowel movement in conscious dogs

The prokinetic effects of mitemcinal, an orally active motilin receptor agonist, on the lower gastrointestinal tracts were investigated in conscious dogs. Oral administration of mitemcinal (0.1-1 mg/kg) stimulated colonic motility, which was measured by chronically implanted force-transducers, as well as gastric motility in a dose-dependent manner. The gastrointestinal contractile activities induced by mitemcinal were inhibited by the continuous intravenous infusion of GM-109, a selective motilin receptor antagonist. Oral administration of mitemcinal (0.3-3 mg/kg) also accelerated bowel movement after feeding without inducing diarrhea in dogs. The results demonstrate that mitemcinal stimulates colonic motility via motilin receptors and the effect of mitemcinal on colonic motility may reflect bowel movement after feeding. Thus, mitemcinal could be a promising agent for treatment of not only the upper but also the lower gastrointestinal motility disorders.

Cytokines differentially regulate ICAM-1 and VCAM-1 expression on human gingival fibroblasts

The expression of intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) on human gingival fibroblasts (HGF) may be important for migration and retention of inflammatory cells in periodontally diseased tissue. This study aimed to assess which cytokines regulate ICAM-1 and VCAM-1 expression on HGF. Tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma enhanced both ICAM-1 and VCAM-1 expression on HGF. Interleukin (IL)-1beta mainly up-regulated ICAM-1 expression. On the other hand, IL-4 and IL-13 enhanced only VCAM-1 expression on HGF. IL-10 did not modulate both ICAM-1 and VCAM-1 expression. Transforming growth factor (TGF)-beta1 enhanced ICAM-1 expression. However, TGF-beta1 inhibited the VCAM-1 expression induced by TNF-alpha or IL-4. Both ICAM-1 and VCAM-1 expression by HGF was inhibited by nuclear factor-kappaB (NF-kappaB) activation inhibitor (MG-132). Mitogen-activated protein kinases (MAPK) inhibitors did not influence ICAM-1 expression induced by TNF-alpha. Interestingly, VCAM-1 expression was enhanced by MEK inhibitor (PD98059) and c-Jun NH2-terminal kinase (JNK) inhibitor (SP600125). These results mean that the balance of cytokines in periodontally diseased tissue may be essential for control of ICAM-1 and VCAM-1 expression on HGF, and the balance of ICAM-1 and VCAM-1 expression might be important for regulation of leucocytes infiltration and retention in periodontally diseased tissue.

horC confers beer-spoilage ability on hop-sensitive Lactobacillus brevis ABBC45cc

AIMS

To determine whether horC confers beer-spoilage ability and to evaluate the validity of horC as a trans-species genetic marker for differentiating the beer-spoilage ability of lactic acid bacteria (LAB).

METHODS AND RESULTS

Hop-sensitive Lactobacillus brevis ABBC45cc was transformed with an expression plasmid, pHYchorBC, containing putative multidrug resistance gene horC and its putative regulator horB, and the transformant was designated as ABBC45cc/pHYchorBC. As a control, ABBC45cc was transformed with pHYchorB that contains horB, and the transformed strain was designated as ABBC45cc/pHYchorB. As a result of beer-spoilage assay of these transformants, ABBC45cc/pHYchorBC exhibited beer-spoilage ability, whereas ABBC45cc/pHYchorB did not. Furthermore ABBC45cc/pHYchorBC showed higher hop resistance than ABBC45cc/pHYchorB, accounting for the differences in beer-spoilage ability observed between the two transformants. ABBC45cc/pHYchorBC also exhibited higher resistance to various structurally unrelated drugs, compared with ABBC45cc/pHYchorB.

CONCLUSIONS

horC was shown to confer hop resistance and beer-spoilage ability on ABBC45cc by presumably encoding a multidrug transporter.

SIGNIFICANCE AND IMPACT OF THE STUDY

The finding that horC plays an important role in hop resistance and beer-spoilage ability supports the validity of horC as a trans-species genetic marker for differentiating the beer-spoilage ability of LAB.

Characterization of horA and its flanking regions of Pediococcus damnosus ABBC478 and development of more specific and sensitive horA PCR method

AIMS

To characterize horA and its flanking regions of Pediococcus damnosus ABBC478 and, on the basis of this insight, to develop a more specific and sensitive horA PCR method.

METHODS AND RESULTS

A plasmid harbouring the homologue of a hop-resistance gene, horA, was sequenced and designated pRH478. The nucleotide sequence and open reading frame structure of horA and its flanking regions of pRH478 were found to be highly similar to those of pRH45, a horA-harbouring plasmid previously identified in Lactobacillus brevis ABBC45. The nucleotide sequence of the horA homologue of P. damnosus ABBC478 was 99.6% identical with that of horA. Based on this insight, new primers specific to horA were designed and compared with the previously reported specific primer pair. As a consequence, it was demonstrated that the new primer pair is superior in specificity and sensitivity.

CONCLUSIONS

The newly developed horA PCR method allows more specific and sensitive determination of the beer-spoilage ability of lactic acid bacteria (LAB).

SIGNIFICANCE AND IMPACT OF THE STUDY

The nucleotide sequences of the horA homologues were found to be essentially identical among distinct species of LAB, indicating that horA-specific primers can be designed from almost any region of the horA gene.

Insulin-Lowering Agents Inhibit Synthesis of Testosterone in Ovaries of DHEA-Induced PCOS Rats

BACKGROUND

Insulin-lowering agents are reported to be useful in treating polycystic ovary syndrome (PCOS) anovulation. It has been suggested that lower insulin levels secondarily affect ovarian tissue, although the direct mechanism of action has not yet been verified. Here we investigated if these agents directly affect the ovary.

METHODS

Thirty female Wister rats were studied. Six control rats were injected subcutaneously with 0.2 ml sesame oil, while 24 rats used as PCOS models were injected subcutaneously with dehydroepiandrosterone (DHEA) and divided into four groups. Six rats were injected with only DHEA, while the remaining 18 rats received metformin, pioglitazone or troglitazone. The ovaries were immunohistochemically stained with anti- testosterone and anti-17beta-HSD antibodies, and then evaluated for morphological changes.

RESULTS

In the DHEA administration group, the number of atretic follicles significantly increased compared to that of control rats. The insulin-lowering agents did not improve the multicystic appearance. Serum testosterone concentrations significantly increased with DHEA administration, but the increase was inhibited by oral administration of insulin-lowering agents. Testosterone deposits in ovarian tissue were also reduced by feeding rats insulin-lowering agents.

CONCLUSION

Insulin-lowering agents affected ovarian tissue by inhibiting testosterone biosynthesis in vivo.

Increase of CCL20 expression by human gingival fibroblasts upon stimulation with cytokines and bacterial endotoxin

We have demonstrated recently that CCL20 was expressed in periodontal diseased tissues and abundant CCR6 positive T cells infiltrated in periodontally diseased tissue. However, it is uncertain which cells can elicit CCL20 production. In the present study, we examined the properties of CCL20 production by human gingival fibroblasts (HGF) culture. Here, we report that interleukin-1 beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and Escherichia coli lipopolysaccharide (LPS) can significantly induce the production of CCL20 by HGF. We found that TNF-alpha and E. coli LPS enhanced the production of CCL20 by HGF treated with IL-1beta. In contrast, interferon-gamma (IFN-gamma) dramatically diminished CCL20 production induced by IL-1beta. Moreover, we demonstrated that nuclear factor-kappaB (NF-kappaB), p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinases (ERK) play an important role in mediating the production of CCL20 induced by IL-1beta and TNF-alpha. On the other hand, we found that not only NF-kappaB, p38 MAPK and ERK but also c-Jun NH2-terminal kinase (JNK) are involved in CCL20 production induced by E. coli LPS. Finally, we found that HGF express CCR6, CCL20 receptor, and CCL20 induced vascular endothelial growth factor (VEGF) by HGF. Taken together, these findings that HGF will be a source of CCL20 in periodontal tissue, and the CCL20 production will be controlled by proinflammatory cytokine and bacterial LPS in periodontally diseased tissue. Thus, CCL20 by HGF might be involved in inflammatory cells infiltration, and promote the progression of periodontal disease.

Genome-wide association study to identify SNPs conferring risk of myocardial infarction and their functional analyses

Myocardial infarction might result from the interactions of multiple genetic and environmental factors, none of which can cause disease solely by each of themselves. Although molecular biological studies revealed that a number of proteins are possibly involved in its pathogenesis, little, if any genetic findings have been reported so far. To reveal genetic backgrounds of myocardial infarction, we performed a large-scale, case-control association study using 92,788 gene-based single-nucleotide polymorphism (SNP) markers. We have identified functional SNPs within the lymphotoxin-alpha gene (LTA) located on chromosome 6p21 that conferred susceptibility to myocardial infarction. Furthermore, we could identify galectin-2 protein as a binding partner of LTA protein. The association study further revealed that a functional SNP in LGALS2 encoding galectin-2, which led to altered secretion of LTA, also indicated a risk of myocardial infarction. A combined strategy of genetic and molecularcellular biological approaches may be useful in clarifying pathogenesis of common diseases.

CXCL12 and CXCR4 expression by human gingival fibroblasts in periodontal disease

CXCL12 is a CXC chemokine that is related to lymphocyte infiltration and angiogenesis in inflammatory sites such as arthritis. However, the expression and roles of CXCL12 in periodontal disease are uncertain. The aim of this study was to assess the expression of CXCL12 and its receptor, CXCR4, in periodontal tissue and to investigate the properties of CXCL12 and CXCR4 expression by human gingival fibroblasts (HGF). RT-PCR analysis revealed that CXCL12 and CXCR4 mRNA were expressed in both normal gingival tissues and periodontal diseased tissues. Immunohistochemistry disclosed that CXCL12 was expressed and CXCR4 positive cells were found in both normal and periodontal diseased gingival tissues. Our in vitro experiments elucidated that HGF constitutively produced CXCL12, and the levels were enhanced by stimulation with tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), regulated upon activation normal T cell expressed and secreted (RANTES) and macrophage inflammatory protein 3(alpha) (MIP-3(alpha)). On the other hand, heat killed Porphyromonas gingivalis (P. gingivalis) and P. gingivalis LPS reduced the CXCL12 production by HGF. Flow cytometry analysis clarified that CXCR4 was highly expressed on HGF, and CXCR4 expression was abrogated by TNF-alpha, IFN-gamma and P. gingivalis LPS. Moreover, CXCL12 induced vascular endothelial growth factor (VEGF) production by HGF. Our results demonstrated that CXCL12 might be related to CXCR4+ cells infiltration and angiogenesis both in normal periodontal tissues and periodontal diseased tissue. P. gingivalis, a known periodontal pathogen, inhibits the production of CXCL12 and the expression of CXCR4 by HGF. This fact means that P. gingivalis may inhibit CXCR4+ cells infiltration and neovascularization in periodontal tissue and escape from the immune response.

Ammonium hexafluorosilicate increased acid resistance of bovine enamel and dentine

Although diamine silver fluoride (AgF: (NH3)2AgF) stains teeth black, it is known as a very effective agent to prevent the dental caries progress. In order to find another fluoride that has a similar anticariogenic effect without changing tooth color, we prepared ammonium hexafluorosilicate (SiF: (NH4)2SiF6), in which the silver of AgF is replaced with silicon. In this study, the anticariogenic effect of SiF was evaluated using bovine teeth. Fluoride solutions, SiF, AgF, acidulated phosphate fluoride (APF), and sodium fluoride (NaF), were applied to bovine enamel and dentine blocks, and the depth of demineralization was measured after exposure to a demineralizing solution for 24 h. Also, fluoride was applied to a simulated dentine caries specimen to evaluate the caries progress-preventing ability. For the dentine specimens, mineral loss (Delta Z) was also measured with microradiography. We found that SiF treated enamel showed better acid resistance than specimens treated with NaF or APF. AgF treated enamel also showed similar acid resistance, but was stained black. SiF and AgF treated caries-affected dentine showed reduced demineralization when exposed to a demineralization solution for 24 h. Mineral loss (Delta Z) was reduced to 85% and 75%, respectively. Although the acid resistance of the SiF treated teeth was inferior to that of the AgF treated teeth, we consider that SiF has good potential as anticariogenic agent, since it increased acid resistance without changing tooth color.

Molecular characterization of a partitivirus from the plant pathogenic ascomycete Rosellinia necatrix

The W8 isolate of the phytopathogenic fungus, Rosellinia necatrix that causes white root rot, contained three segments of double-stranded (ds) RNA, namely L1, L2 and M. Purified viral particles of about 25 nm in diameter contained an RNA segment with almost the same mobility as M-dsRNA, but the band was sensitive to S1 nuclease. Molecular analysis revealed that M-dsRNA consisted of two (RNA 1 and RNA 2) similarly sized species of 2299 and 2279 bp excluding an interrupted poly (A or U) tail of 16-51 bp. The predicted largest open reading frame in RNA 1 and RNA 2 was similar to those of RNA dependent RNA polymerase (RdRp) and coat protein (CP), respectively, encoded by the family Partitiviridae. The non-coding regions (NCR) of the two segments were similar (approximately 70% base identity) at the 5' end, but different at the 3' end. The NCR at the 3' end contained adenosine-uracil rich elements (AREs) in both segments. Northern analyses revealed RNA 1 and RNA 2 in mycelial and viral particle fractions. We coined the name Rosellinia necatrix partitivirus 1-W8 (RnPV1-W8) for M-dsRNA based on viral particle morphology and sequence information.

Pigmented Cutaneous Papillomatosis (Pigmented Epidermal Nevus) in Three Pug Dogs; Histopathology, Electron Microscopy and Analysis of Viral DNA by the Polymerase Chain Reaction

Canine pigmented epidermal nevus (CPEN) is a skin disorder of some breeds of dog characterized by multiple black plaques of the haired and non-haired skin. Three cases of pigmented cutaneous papillomatosis (previously described also as CPEN) in pug dogs were investigated histopathologically, immunohistochemically and electron microscopically. Additionally, DNA analyses with the polymerase chain reaction (PCR) were performed in two cases. Many nuclei of the stratum granulosa were diffusely immunolabelled for specific structural antigens of bovine papillomavirus (subgroup A), but nuclear inclusion bodies were not detected by retrospective examination of haematoxylin and eosin-stained sections of the affected skin. Aggregates of small numbers of viral particles (ranging from 37 to 43 nm in diameter) with a hexagonal structure were sparsely scattered throughout the nuclei of some of the superficial keratinocytes. PCR amplification targeted for the L1 gene of papillomavirus cloned from a case of CPEN yielded an expected fragment of 194-bp in the two CPEN cases examined but not in a case of canine oral papilloma.

Genetic marker for differentiating beer-spoilage ability of Lactobacillus paracollinoides strains

AIMS

To determine whether the beer-spoilage ability is an intrinsic character of Lactobacillus paracollinoides and identify a genetic marker for differentiating the beer-spoilage ability of strains belonging to this species.

METHODS AND RESULTS

The ribotype of a nonspoilage strain, Lact. brevis ATCC8291, was found to be identical with that of Lact. paracollinoides LA7. The 16S rDNA sequence analysis and DNA-DNA hybridization study indicates that nonspoilage ATCC8291 should belong to Lact. paracollinoides. We further isolated nonspoilage variants from Lact. paracollinoides LA2(T) and LA9 by incubating these strains at 30 degrees C. To identify a genetic marker for differentiating the beer-spoilage ability of Lact. paracollinoides, open reading frames 5 (ORF5), the previously reported genetic marker for Lact. brevis, was evaluated. As a result, ORF5 homologues were detected in all of the 12 beer-spoilage strains of Lact. paracollinoides, while this ORF was not found in ATCC8291 or the two nonspoilage variants obtained from LA2(T) and LA9.

CONCLUSIONS

Lactobacillus paracollinoides is not an intrinsic beer-spoiler and the nonspoilage strain Lact. brevis ATCC8291 should be reclassified as Lact. paracollinoides. ORF5 was found to be useful for differentiating beer-spoilage ability of this species.

SIGNIFICANCE AND IMPACT OF THE STUDY

The finding that Lact. paracollinoides includes nonspoilage strains necessitates brewers to use a genetic marker that is associated with the beer-spoilage ability of this species.

Comparative analysis of conserved genetic markers and adjacent DNA regions identified in beer-spoilage lactic acid bacteria

AIMS

To conduct an inter-species comparative study on the nucleotide sequences of the conserved DNA regions surrounding ORF5, a genetic marker for differentiating beer-spoilage lactic acid bacteria.

METHODS AND RESULTS

The conserved DNA regions surrounding ORF5 were examined by PCR analysis, using three beer-spoilage strains, Lactobacillus brevis ABBC45C, L. paracollinoides LA2T and Pediococcus damnosus ABBC478. As a result, the DNA regions containing ORF1-7, originally found in ABBC45C, appeared to be conserved among the three strains, while the downstream region was not found in L. paracollinoides LA2T and P. damnosus ABBC478. The sequencing analysis of the conserved DNA regions of LA2T and ABBC478 revealed ca 99% nucleotide sequence identities with that of ABBC45C.

CONCLUSIONS

The nucleotide sequences of the ca 8.2 kb DNA regions containing ORF1-7 were virtually identical among the three strains belonging to different species. The internal organizations of the ORFs were found to be remarkably similar.

SIGNIFICANCE AND IMPACT OF THE STUDY

The level of nucleotide sequence identities suggests the DNA regions surrounding ORF5 were horizontally acquired by these beer-spoilage strains belonging to the three different species of lactic acid bacteria.

Using a vortex mixer for testicular sperm collection

OBJECTIVE

To evaluate 2 methods of processing testicular tissue for the retrieval of viable sperm from men with nonobstructive azoospermia.

STUDY DESIGN

Fresh testicular tissue was obtained from nonobstructive azoospermia patients using a biopsy needle. The specimens were divided into 2 fractions. All specimens were minced and immersed in human tubal fluid (HTF). The first fraction was filtered through a nylon filter and incubated for 3 hours. The supernatant was centrifuged, resuspended in HTF and analyzed. The second fraction was immediately vortexed for 5 minutes and filtered through a nylon filter. The supernatant was centrifuged, resuspended in HTF and analyzed.

RESULTS

Spermatozoa were obtained in 13 of 24 cases (54.2%) using the vortex method and in 5 of 24 cases (20.8%) with the nylon filter method.

CONCLUSION

The vortex mixing method may be a better option than the conventional method for processing testicular tissue for sperm collection.

Expression and distribution of cyclooxygenase-2 in human ovary during follicular development

Prostaglandins play important roles for oocyte maturation and follicular rupture. Cyclooxygenase-2 (COX-2), an inducible isoform of a prostaglandin metabolic enzyme, is essential for the timed production of prostaglandins in the ovary. The aim of the present study is to examine expression and distribution of COX-2 in human ovarian follicles at each of the maturation stages. Immunohistochemical staining shows that COX-2 is expressed in the granulosa cell layer of secondary and developing follicles, but is not detected in primary and Graafian follicles. Western blotting analysis revealed the existence of COX-2 in periovulatory follicular fluid at a mean concentration of 5.6 +/- 0.6 ng/ml. COX-2 might begin to be produced at the secondary follicle stage, and once a follicle reaches the Graafian follicle stage, the production of this enzyme is stopped. After exposure to luteinizing hormone (LH) surge, follicles might resume production of COX-2, and this is secreted into the follicular fluid.

Abscess-forming inflammatory granulation tissue with Gram-positive cocci and prominent eosinophil infiltration in cats: possible infection of methicillin-resistant Staphylococcus

We occasionally encounter feline cervical or mesenteric lesions diagnosed histopathologically as abscess or inflammatory granulation tissue with eosinophil infiltration. Gram-positive cocci accompany the lesions. In the present study, such lesions obtained from 27 cats were examined to evaluate the histopathologic features and the nature of the causative bacteria. The average age was 7.3 +/- 3.5 years. No sex predilection was observed. Most frequent locations of the lesions included the abdominal cavity with/without mesenteric lymph nodes (11/27, 41%) and subcutaneous tissue or lymph nodes of the neck (9/27, 33%). Common clinical presentation was a localized mass. Grossly, the lesions contained abscesses in the center and were surrounded by fibrous tissue. Microscopically, the necrotic zone contained bacterial colonies. Large numbers of eosinophils and macrophages infiltrated the area surrounding the necrotic tissue. The surrounding connective fiber-rich granulation tissue demarcated the eosinophilic abscess. The bacteria were Gram-positive cocci in 23 of the 27 cats and were positive for anti-staphylococcus antiserum in 19 of the 23 cats. In 15 out of 17 lesions, the colonies expressed immunoreactivity to penicillin-binding protein 2', which is a drug-resistance gene product of methicillin-resistant Staphylococcus (MRS) species. These findings suggest strongly that MRS causes this type of infectious lesion.