Pseudo-high affinity interleukin 2 (IL-2) receptor lacks the third component that is essential for functional IL-2 binding and signaling.

Functional studies of the interleukin 2 receptor (IL-2R) of two (ED515-D and Kit225) IL-2-dependent and three (ED515-I, 3T3-alpha beta 11, and Hut102) IL-2-independent cell lines were done. All of these cell lines appeared to express high as well as low affinity IL-2R. However, ED515-I and 3T3-alpha beta 11, which expressed the IL-2R beta chain, did not bind IL-2 at all when IL-2 binding to their IL-2R alpha chain was blocked with anti-Tac monoclonal antibody, whereas the intermediate affinity binding in ED515-D, Kit225, and Hut102 cells remained. We tentatively called the high affinity IL-2R of the former cells pseudo-high affinity IL-2R. The dissociation constant of pseudo-high affinity IL-2R was higher than that of ordinary high affinity IL-2R. Internalization of cell-bound 125I-IL-2 into ED515-I and 3T3-alpha beta 11 cells was less efficient than that into ED515-D cells. The addition of IL-2 neither promoted cell growth nor upregulated IL-2R alpha chain expression in ED515-I and 3T3-alpha beta 11 cells. Furthermore, tyrosine phosphorylation of the cellular proteins (p120, p98, p96, p54, and p38) was induced or enhanced in response to the addition of IL-2 in ED515-D and Kit225 cells, but not in the cell lines expressing pseudo-high affinity IL-2R. Finally, 125I-IL-2 crosslinking followed by SDS-PAGE analysis showed an 80-kD band corresponding to p65 + IL-2, in addition to bands corresponding to IL-2R alpha and beta chain + IL-2 in cells bearing ordinary high affinity IL-2R but not in cells with pseudo-high affinity IL-2R. Taken together, we consider that another protein whose molecular mass is approximately 65 kD is functionally important in IL-2 binding and subsequent signal transduction and may be the third component of IL-2R.

Differences between subtotal corpectomy and laminoplasty for cervical spondylotic myelopathy.

OBJECTIVE: This study aimed to obtain guidelines for choosing between subtotal corpectomy (SC) and laminoplasty (LP) by analysing the surgical outcomes, radiological changes and problems associated with each surgical modality. STUDY DESIGN: A retrospective analysis of two interventional case series. SETTING: Department of Orthopaedic Surgery, Kagawa University, Japan. METHODS: Subjects comprised 34 patients who underwent SC and 49 patients who underwent LP. SC was performed by high-speed drilling to remove vertebral bodies. Autologous strut bone grafting was used. LP was performed as an expansive open-door LP. The level of decompression was from C3 to C7. Clinical evaluations included recovery rate (RR), frequency of C5 root palsy after surgery, re-operation and axial pain. Radiographic assessments included sagittal cervical alignment and bone union. RESULTS: Comparisons between the two groups showed no significant differences in age at surgery, preoperative factors, RR and frequency of C5 palsy. Progression of kyphotic changes, operation time and volumes of blood loss and blood transfusion were significantly greater in the SC (two- or three-level) group. Six patients in the SC group required additional surgery because of pseudoarthrosis, and four patients underwent re-operation because of adjacent level disc degeneration. In the LP group, the problem of elimination of postoperative axial symptoms remains to be solved. CONCLUSIONS: The merit of SC is the low frequency of axial symptoms. One-level SC can be considered to have similar degree of invasiveness as LP. Compared with SC, LP is more suitable for elderly patients with multilevel stenosis.

Scoliosis, diabetes mellitus and total laminectomy at the 4th lumbar vertebra are independent risk factors for post-laminectomy fracture around the isthmus.

OBJECTIVE: We aimed to identify the risk factors and clinical outcomes for post-laminectomy fracture around the isthmus, which can cause back pain or radiculopathy. METHODS: We performed a retrospective cohort study involving all patients who underwent laminectomy splitting the spinous process for lumbar spinal stenosis between 2010 and 2014. The primary outcome measure was post-laminectomy fracture around the isthmus. Clinical outcomes were evaluated based on reoperation rate. To evaluate risk factors for fracture, the following parameters were collected: (1) patient characteristics and concomitant diabetes mellitus, (2) lumbar scoliosis and sagittal alignment parameters, and (3) surgical data, such as rate of total laminectomy. Logistic regression analysis was performed to identify the independent risk factors for post-laminectomy fracture. RESULTS: Twelve of the 92 patients suffered a post-laminectomy fracture around the isthmus. Logistic regression analysis revealed that diabetes mellitus (odds ratio [OR]: 15.41; 95% confidence interval [CI]: 2.93-80.98; P=0.001), L4 total laminectomy (OR: 14.68; 95% CI: 1.51-142.76; P=0.021), and lumbar scoliosis (OR: 5.72; 95% CI: 1.16-28.21; P=0.032) were independent risk factors. The fracture group included 2 patients (16.7%) who required reoperation at the decompression level for recurrent leg pain, whereas the non-fracture group included 2 (2.5%) who underwent reoperation at a level different from the index procedure. CONCLUSIONS: Post-laminectomy fractures around the isthmus were significantly associated with scoliosis, diabetes mellitus, and total laminectomy at L4. Total laminectomy at L4 is best avoided to reduce the risk of post-laminectomy fracture in patients with scoliosis or diabetes mellitus.

Principal component analysis uncovers cytomegalovirus-associated NK cell activation in Ph+ leukemia patients treated with dasatinib.

Dasatinib treatment markedly increases the number of large granular lymphocytes (LGLs) in a proportion of Ph+ leukemia patients, which associates with a better prognosis. The lymphocytosis is predominantly observed in cytomegalovirus (CMV)-seropositive patients, yet detectable CMV reactivation exists only in a small fraction of patients. Thus, etiology of the lymphocytosis still remains unclear. Here, we identified NK cells as the dominant LGLs expanding in dasatinib-treated patients, and applied principal component analysis (PCA) to an extensive panel of NK cell markers to explore underlying factors in NK cell activation. PCA displayed phenotypic divergence of NK cells that reflects CMV-associated differentiation and genetic differences, and the divergence was markedly augmented in CMV-seropositive dasatinib-treated patients. Notably, the CMV-associated highly differentiated status of NK cells was already observed at leukemia diagnosis, and was further enhanced after starting dasatinib in virtually all CMV-seropositive patients. Thus, the extensive characterization of NK cells by PCA strongly suggests that CMV is an essential factor in the NK cell activation, which progresses stepwise during leukemia and subsequent dasatinib treatment most likely by subclinical CMV reactivation. This study provides a rationale for the exploitation of CMV-associated NK cell activation for treatment of leukemias.

Lifting of evacuation orders and subsequent efforts in Japan.

With confirmation of the cold shutdown conditions of the nuclear reactors after the accident at Fukushima Daiichi nuclear power plant, the Japanese Government reclassified the areas under evacuation orders as follows: (1) difficult-to-return zones (>50 mSv y-1), (2) restricted residence zones (20-50 mSv y-1), and (3) zones in preparation for lifting of the evacuation order (<20 mSv y-1). The Government continued its initiatives towards reconstruction of Fukushima, and has lifted evacuation orders in Zones 2 and 3. In terms of radiological protection, the Government emphasised its policy of placing importance on individual dose, and promoted the assignment of consultants in each municipality.

Prognosis after mastectomy versus repeat lumpectomy in patients with ipsilateral breast cancer recurrence: A propensity score analysis.

INTRODUCTION: Mastectomy is the current standard surgical procedure for ipsilateral breast tumor recurrence (IBTR). However, there is little evidence about the prognostic impact of the surgical procedure (mastectomy versus repeat lumpectomy) for IBTR. PATIENTS AND METHODS: A total of 271 consecutive patients who had histologically confirmed IBTR without distant metastases and underwent definitive surgery for IBTR between 1989 and 2008 were included from eight institutions in Japan. The impact of the surgical procedure for IBTR on distant disease-free survival (DDFS) and overall survival (OS) was evaluated using and multivariable proportional hazards regression and propensity score matching methods. RESULTS: Of the 271 patients, 149 patients (55%) underwent repeat lumpectomy and 122 patients (45%) underwent mastectomy after IBTR. The median follow-up period from definitive surgery for IBTR was 55 months. There was no difference in terms of DDFS and OS between repeat lumpectomy and mastectomy after IBTR, adjusted for various clinical and tumor characteristics. In addition, for the matched patient cohort, no difference in DDFS and OS was seen between the 2 groups. CONCLUSION: In our study, both multivariate analysis and the propensity score matching method demonstrated that there was no difference in terms of DDFS and OS between repeat lumpectomy and mastectomy after IBTR. Further studies are warranted (UMIN-CTR number UMIN000008136).

Local recurrence risk after previous salvage mastectomy.

INTRODUCTION: Breast-conserving surgery is a standard treatment for early breast cancer. For ipsilateral breast tumor recurrence (IBTR) after breast-conserving surgery, salvage mastectomy is the current standard surgical procedure. However, it is not rare for patients with IBTR who have received salvage mastectomy to develop local recurrence. In this study, we examined the risk factors of local recurrence after salvage mastectomy for IBTR. PATIENTS AND METHODS: A total of 118 consecutive patients who had histologically confirmed IBTR without distant metastases and underwent salvage mastectomy without irradiation for IBTR between 1989 and 2008 were included from eight institutions in Japan. The risk factors of local recurrence were assessed. RESULTS: The median follow-up period from salvage mastectomy for IBTR was 4.6 years. Patients with pN2 or higher on diagnosis of the primary tumor showed significantly poorer local recurrence-free survival than those with pN0 or pN1 at primary tumor (p < 0.001). Multivariate analysis showed that the lymph node status of the primary tumor was a significantly independent predictive factor of local recurrence-free survival (p = 0.02). CONCLUSION: The lymph node status of the primary tumor might be a predictive factor of local recurrence-free survival after salvage mastectomy for IBTR. Further research and validation studies are needed. (UMIN-CTR number UMIN000008136).

Internal tandem duplication of FLT3 associated with leukocytosis in acute promyelocytic leukemia. Leukemia Study Group of the Ministry of Health and Welfare (Kohseisho).

FLT3 is a member of receptor tyrosine kinases expressed in leukemia cells, as well as in hematopoietic stem cells. Recently, a somatic alteration of the FLT3 gene was found in acute myeloid leukemia, as an internal tandem duplication (FLT3/ITD) which caused elongation of the juxtamembrane (JM) domain of FLT3. Here we characterized the FLT3/ITD and investigated its clinical significance in acute promyelocytic leukemia (APL). Seventy-four newly diagnosed patients with APL, who were treated with the same protocol in a multi-institutional study, were studied for the FLT3/ITD. Genomic and message sequences of the FLT3 gene were amplified by means of polymerase chain reaction (PCR), and elongated PCR products were sequenced. Fifteen patients (20.3%) had FLT3/ITD, all of which were transcribed in frame. Location of the duplicated fragments (six to 30 amino acids) varied from patient to patient. However, they always contained either Y591 or Y599, but the tyrosine kinase domain was not significantly affected. This finding implied that signal transduction of FLT3 is amplified by the duplication. Clinically, the presence of FLT3/ITD was related to high peripheral white blood cell counts as well as peripheral leukemia cell counts (P < 0.0001), high LDH level (P = 0.04), and low fibrinogen concentration (P = 0.04). These data suggest that FLT3/ITD plays a significant role in progression of APL.

Alteration of p16 (CDKN2) gene is associated with interleukin-2-induced tumor cell growth in adult T-cell leukemia.

Because tumorigenesis frequently involves the dysfunction of cell cycle-related proteins, we examined the effect of mutations in CDK inhibitor p16 and its linked genomic loci p15, cl.B, and 1063.7 on the growth of primary adult T-cell leukemia (ATL) cells. Southern blot analysis of primary ATL cells showed a significantly higher incidence of p16 gene alteration in acute ATL than in chronic ATL [67.7% (23/34) vs. 26.1% (6/23), respectively; p<0.003]. Similarly, polymerase chain reaction (PCR) analysis of p16 exon 2 revealed a higher incidence of alteration in acute ATL than in chronic ATL [52.9% (18/34) vs. 26.1% (6/23), respectively; p<0.05]. PCR-single strand conformation polymorphism analysis of exons 1 and 2 of p16 showed no mutations in the patients, with normal pattern by Southern blotting or PCR analysis. Notably five of six chronic ATL patients with abnormal p16 genes progressed to acute crisis within 4 months. PCR analysis of the p16 linked loci 1063.7, p15 exon 2, and cl.B found homozygous deletion in 55.9%, 20.6%, and 2.9% of acute ATL cells and 39.1%, 13.0%, and 0% of chronic ATL cells, respectively, showing no relationship of homozygous deletion in either loci with disease subtypes. In most cases, deletions were seen in multiple genes, including p16. Acute ATL cells had a higher frequency of multigene deletions than chronic ATL cells [44.1% vs. 17.4%; p<0.05]. When leukemic cells were analyzed for interleukin 2 (IL-2) responsive growth, only p16 gene alteration was directly associated with leukemic cell growth activity. Among leukemic cells showing high IL-2 responsiveness, 73.1% (19/26) had p16 gene alteration vs. 27.8% (5/18) of leukemic cells that showed low IL-2 responsiveness (p<0.005). p16 gene alteration was found in 73.3% (14/19) of leukemic cells showing high autonomous growth rates but in only 40.0% (10/25) of those leukemic cells showing low autonomous growth (p<0.03). These results suggest the following: alteration of p16-related genomic regions in ATL is usually a wide rearrangement including the p16 gene; within this region, only p16 gene alteration is associated with disease aggressiveness; and p16 gene deletion may be a proximate event in leukemogenesis.

NF-kappaB involvement in the activation of primary adult T-cell leukemia cells and its clinical implications.

The HTLV-I provirus-encoded Tax protein induces NF-kappaB in Tax-transfected Jurkat T cells or HTLVL-I- infected T cells in vitro. Tax induction of NF-kappaB is presumed to be involved in proliferation and activation of primary leukemia cells in vivo. Recent studies have demonstrated that NF-kappaB activities in human T cells are mediated by at least four c-Rel-related DNA binding proteins - p50, p55, p75 and p85. We examined the significance of NF-kappaB induction in primary adult T cell leukemia cells and the induction kinetics of each of the four NF-kappaB species. Marked NF-kappaB activity was detected using an electrophoretic mobility shift assay (EMSA) in the primary cells of patients with acute disease, but little activity was noted in the cells of chronic patients. NF-kappaB activity was enhanced in a time-dependent manner in acute type cells cultured with mitogen-free medium; there was no induction of activity in chronic type cells. UV crosslinking demonstrated all four species of NFkappaB complex - high levels of p50 and lower levels of p55 and p75, in acute type cells; chronic type cells showed only the p50. As a control, normal resting T cells similarly showed only p50; control cells showed little change in activity when cultured without mitogenic stimulation, analogous to chronic type ATL. Northern blotting revealed enhancement of c-rel (encoding p85) and KBFI (encoding p50 and p55) expression in acute type cells during culture, while there was no significant enhancement of mRNAs in chronic type ATL cells or unstimulated normal T cells. Northern blotting also revealed that Tax is upregulated at the mRNA level in acute- but not chronic-type cells during culture. Expression of c-rel and KBF1 mRNAs in acute type cells appeared to be related to Tax mRNA expression. These results suggest that Tax is capable of inducing nuclear expression of all four NF-kappaB species in primary ATL cells of acute type patients, with marked effects on p55, p75, and p85. Tax induction of NF-kappaB species is regulated, at least in part, at a pretranslational level involving increases in c-rel and KBF1 mRNA.

Human T lymphotropic virus-type I Tax induction of CD21/Epstein-Barr virus receptor expression on T cells and its significance in leukemogenesis of adult T cell leukemia.

CD21, which is expressed on B cells, is also expressed on human T lymphotropic virus-type I (HTLV-I)-infected T cell lines. CD21 also serves as a receptor of Epstein-Barr virus (EBV). We evaluated the mechanism of CD21 induction on HTLV-I-infected T cells and its clinical significance in the leukemogenesis of adult T cell leukemia (ATL). CD21 induction was detected at very low levels in T cell lines (Jurkat and CEM cells), and in non- or low-Tax-producing HTLV-I-infected T cell lines (Oh13T, S1T, and Su9T01 cells). In contrast, marked induction of CD21 was detected in high-Tax-producing HTLV-I-infected T cell lines (K3T, F6T, and MT-2). A Jurkat T cell clone stably transfected with tax-expressing cDNA expressed a significant amount of CD21 on the cell surface. These results strongly suggest that HTLV-I Tax induces CD21 on T cells. On two-color analysis, CD21 expression was detected in CD4+ T cells of the primary ATL cells from a subset of patients, suggesting that EBV infection may be associated with the leukemogenesis of ATL, at least in part. However, no genome of EBV was detected in the genomic DNA of six HTLV-I-infected T cell lines or the primary ATL cells separated from all patients, indicating the irrelevance of EBV infection to ATL leukemogenesis.

Vesnarinone exhibits antitumor effect against myeloid leukemia cells via apoptosis.

Vesnarinone is a positive inotropic agent used for treating congestive heart failure. We evaluated its ex vivo effects on myeloid leukemia cell lines and primary acute myelogenous leukemia cells. Vesnarinone inhibited the incorporation of radiolabeled thymidine by a myeloid cell line, HL60, in a dose-dependent manner at concentrations ranging from 0.1 to 30 microg/mL. A maximum 40% suppression was seen at a concentration of 10 microg/mL. Determination of viable cell counts by trypan blue dye exclusion method demonstrated vesnarinone to be cytocidal for HL60 cells. Vesnarinone induced DNA fragmentation as detected by electrophresis in HL60 cells after 72-hour culture; this effect was not inhibited by G-CSF. The apoptosis induced by vesnarinone was also detected by the in situ end-labeling method. Northern blot analysis showed a reduction of c-myc mRNA expression in HL60 cells by vesnarinone. However, immunostaining assay showed no change in the expression of Fas and Bcl-2 proteins. We next examined the effect of vesnarinone on primary myeloid leukemia cells derived from 10 patients: 3 cases of M1, 2 of M2, 3 of M3, 1 of M4, and 1 of M6, by the French-American-British classification. Vesnarinone inhibited the incorporation of thymidine in all cells, with a mean suppression of 58.1%. DNA electrophoresis showed induction of DNA fragmentation in cultured cells with vesnarinone for 72 hours in 8 of the 10 patients with primary leukemia. However, bone marrow mononuclear cells from healthy controls showed no growth suppression or DNA fragmentation in response to vesnarinone. These results suggest that vesnarinone may be useful in treating myeloid leukemia.

Change in estrogen receptor, HER2, and Ki-67 status between primary breast cancer and ipsilateral breast cancer tumor recurrence.

INTRODUCTION: Changes in the biological marker status between primary and recurrent tumors are observed in breast cancer. However, their clinical significance is still uncertain, especially for patients with ipsilateral breast tumor recurrence (IBTR) after breast-conserving surgery. PATIENTS AND METHODS: A total of 117 patients with IBTR without distant metastases were enrolled in this study. All patients were examined for estrogen receptor (ER), HER2, and Ki-67 in both the primary tumors and paired IBTR. We evaluated the impact of changes in these biomarkers between primary tumors and IBTR on the prognosis after IBTR. RESULTS: There were no associations of changes in the ER, HER2 status with distant disease-free survival (DDFS) after surgical resection of IBTR, whereas the change in the Ki-67 status between the primary tumors and IBTR was significantly correlated with DDFS (unadjusted: p = 0.0094; adjusted: p = 0.013). Patients in the "increased or remained high" Ki-67 group had a significantly shorter DDFS than those in the "decreased or remained low" Ki-67 group (5-year DDFS: 55.5 vs. 79.3%, respectively, p = 0.0084 by log-rank test). CONCLUSION: An increased or persistently high Ki-67 status in the IBTR was significantly correlated with a poorer prognosis after IBTR.

Histamine increases the expression of LOX-1 via H2 receptor in human monocytic THP-1 cells.

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a member of the scavenger receptor family, and is known to be expressed in monocytes/macrophages. We investigated the effect of histamine on the expression of LOX-1 in cells of the human monocytic leukemia cell line THP-1. Histamine as well as forskolin and dibutyryl cyclic AMP (Bt2-cAMP) stimulated the THP-1 monocytes to express the LOX-1 gene at the transcription level. This histamine effect on LOX-1 gene expression, via the histamine H2 receptor-mediated cAMP signal transduction pathway, was reduced after differentiation of the cells into macrophages, even though forskolin and Bt2-cAMP still enhanced the gene expression. The alteration of the responsiveness of LOX-1 expression to histamine was related to suppressed expression of the H2 receptor in THP-1 macrophages. The switch of the predominant class of histamine receptors between H1 and H2 would modulate the effects of histamine on LOX-1 gene expression in monocytes and macrophages, and therefore, would play a certain role in the inflammatory aspects of atherogenesis.

Effects of histamine and interleukin-4 synthesized in arterial intima on phagocytosis by monocytes/macrophages in relation to atherosclerosis.

We investigated the localization of histidine decarboxylase (HDC), which is the rate-limiting enzyme that generates histamine from histidine, in human aorta/coronary artery. RT-PCR and immunohistochemical staining revealed that the HDC gene was expressed in monocytes/macrophages and T cells in the arterial intima but not in smooth muscle cells in either the arterial intima or the media. A luciferase promoter assay with U937 and Jurkat cells demonstrated that interleukin-4 (IL-4) inhibited the expression of the HDC gene. In contrast, among a scavenger receptor family, IL-4 as well as histamine up-regulated U937 cells to express the LOX-1 gene but not the SR-A gene, which genes encode receptors that scavenge oxidized lipids. These findings suggest that histamine synthesized in the arterial wall participates in the initiation and progression of atherosclerosis and that IL-4 can act as an important inhibitory and/or stimulatory factor in the function of monocytes/macrophages modulated by histamine in relation to the process of atherosclerosis.

Shortened microsatellite d(CA)21 sequence down-regulates promoter activity of matrix metalloproteinase 9 gene.

One characteristic elements in the promoter of the matrix metalloproteinase 9 (MMP-9) gene is the d(CA) repeat. To investigate whether this element regulates the transcription of the MMP-9 gene and its enzymatic activities, we sequenced the promoter region isolated from esophageal carcinoma cell lines. TE9 cells with low MMP-9 enzymatic activity had the number of d(CA) repeats shortened from 21 to 14 or 18. TE8, TE10 and TE11 cells with high MMP-9 activities had 21 or 23 d(CA) repeats. Luciferase assays using MMP-9 promoter containing 18, 14 or 0 d(CA) repeats showed transcriptional activities which were 50, 50 or 5%, respectively, of the level achieved with promoter containing 21 d(CA) repeats. Sequence analysis of the promoter of 223 Japanese subjects revealed that most had two alleles with 20, 21 or 22 d(CA) repeats, whereas six had one or two alleles with 14, 18 or 19 d(CA) repeats. We postulate that length alteration of the d(CA) repeat causes phenotypic differences among carcinoma cells and that microsatellite instability may contribute to the polymorphism of d(CA) repeat length.

Switch of histamine receptor expression from H2 to H1 during differentiation of monocytes into macrophages.

It is known that histamine suppresses gene expression and synthesis of tumor necrosis factor alpha (TNF-alpha) induced by lipopolysaccharide (LPS) in human peripheral blood mononuclear monocytes (HPM) or alveolar macrophages via histamine H2 receptors. We investigated the effect of histamine and differentiation in macrophages on the expression and secretion of TNF-alpha, TNF-alpha-converting enzyme (TACE), and histamine H1 and H2 receptors by use of a leukemia cell line, U937, and HPM. Differentiation of U937 and HPM cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) enhanced the H1 receptor expression and rather suppressed the H2 receptor, resulting in up-regulation of the histamine-induced expression and secretion of TNF-alpha, modulated via TACE. Therefore, histamine failed to inhibit up-regulated expression of TNF-alpha induced by LPS in macrophages. The switch from H2 to H1 receptors during differentiation in the monocyte/macrophage lineage could participate in the pathogenic processes of atherosclerosis and inflammatory reactions in the arterial wall.

A role for interleukin 4 in production of matrix metalloproteinase 1 by human aortic smooth muscle cells.

Effect of interleukin 4 (IL-4) on the production of matrix metalloproteinase 1 (MMP-1) by normal and immortalized human intimal smooth muscle cells (SMC) was investigated. The production of the precursors of MMP-1 by intimal SMC was enhanced in a dose-dependent manner by addition of IL-4 to the culture medium, whereas the cytokine also showed an inhibitory effect on DNA synthesis in the cells. In addition, mRNA of IL-4 was found in the atherosclerotic and nonatherosclerotic areas of the intima. Although the production of MMP-1 and the proliferation of SMC are thought to play an important role in reconstruction of the intima during atherogenesis, our results suggest a possible role of IL-4 induced MMP-1 in inhibiting tissue remodeling caused by a variety of arterial disorders including atherosclerosis.

Expression of stem cell factor in human aortic endothelial and smooth muscle cells.

It has been confirmed that the receptor protein encoded by the c-kit proto-oncogene is expressed by cells of the hematopoietic, gonadal, pigment, and mast cell lineages and that its ligand, stem cell factor (SCF), is mainly expressed in their microenvironment. In a previous study we investigated the expression of the c-kit gene in human aortic endothelial cells (EC). In the present study we investigated the expression of SCF in human aortic EC and smooth muscle cells (SMC). Reverse transcription (RT)-PCR and Northern blot analyses showed that both human arterial EC and SMC expressed mRNA specific for the SCF gene. In addition, tissue-specific expression of the SCF gene was confirmed by in situ hybridization in the EC and the SMC. Western blot analysis and immunocytochemistry showed evidence of production of SCF protein in both the EC and the SMC. These results indicate the existence of mast cell-SMC interaction and of an autocrine loop of c-kit and its ligand on the surface of EC, suggesting that the interaction between c-kit protein and SCF may play an important role in metabolism of arterial wall and in the pathogenesis of atherosclerosis in the arterial intima.

Suppression of adjuvant arthritis of rats by a novel matrix metalloproteinase-inhibitor.

BAY 12-9566 (4-[4-(chlorophenyl)phenyl]-4-oxo-2S-(phenylthiomethyl) butanoic acid) is a newly developed, synthetic matrix metalloproteinase (MMP) inhibitor (MMPI) that selectively inhibits MMP-2, MMP-3 and MMP-9 isozymes. We study the effect of BAY 12-9566 on inflammation and cartilage destruction in adjuvant-induced arthritis (AA) in rats. Rats were injected with adjuvant and treated for 21 days with vehicle, Indomethacin or BAY 12-9566. AA was assessed: by measuring arthritic index, paw volume, urinary pyridinoline (Pyr) and deoxypyridinoline (Dpyr); by examining joint inflammation; and by microscopic morphometry of articular cartilages. Oral treatment of rats for 22 days with 50 mg kg(-1) body weight/d BAY 12-9566 showed decreased AA as determined by improvement in body weight gain (P<0.01), arthritic index (P<0.05) and swelling of paws contralateral to the adjuvant injection site (P<0.05). Neutrophil infiltration and collagen degradation were also significantly lower (P<0.01) in this treatment group. Cartilage destruction was successfully suppressed (P<0.01) in rats treated with either 50 mg kg(-1) body weight/d BAY 12-9566 or 1 mg kg(-1) body weight/d Indomethacin. These results indicate that BAY 12-9566 successfully suppressed inflammation and cartilage destruction in rats with AA. Moreover, these results also suggested that MMP-2, MMP-3 and MMP-9 are involved in arthritic diseases such as rheumatoid arthritis.