Masanori Inaba

Juntendo University, Edo, Tōkyō, Japan

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Publications (5)9.25 Total impact

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    ABSTRACT: Peritoneal dialysis (PD) catheters often become severely dislocated, which may lead to malfunction. With the aim of preventing this complication, we have developed a simple method of fixing the catheter downwards in the peritoneal cavity (fixation technique), a technique that does not require a laparoscope. Sixteen patients were implanted using the conventional placement technique and 25 patients were implanted using the fixation technique. The location of the catheter tip was classified from grade 1 (downward, normal) to 5 (dislocated). The frequency of dislocation (defined as the extended time and/or decrease in volume when draining the PD solution) was measured for both the fixation technique and conventional placement technique. There was a significant difference in grade between the fixation technique (2.72 ± 1.01) and conventional technique (3.92 ± 1.31). The time until first dislocation was significantly different between the fixation technique (59.3 ± 48.1 days) and conventional technique (8.8 ± 14.6 days). The time until any dislocation was significantly different between the fixation technique (69.2 ± 41.9 days) and conventional technique (12.9 ± 13.7 days). Complications were not significantly different between the fixation technique and conventional technique. The fixation technique appears to be simple, safe, and useful for preventing severe dislocation and for lengthening the time until dislocation in PD patients.
    Seminars in Dialysis 11/2013; · 2.25 Impact Factor
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    ABSTRACT: Marked thickening of the peritoneum and vasculopathy in the submesothelial compact zone have been reported in long-term peritoneal dialysis patients. Bone marrow (BM)-derived cell lines are considered to be useful tools for therapy of various diseases. To clarify the role of BM-derived cells in the peritoneal fibrosis (PF) model, we analyzed several lineages of cells in the peritoneum. BM cells from green fluorescent protein (GFP) transgenic mice were transplanted into naïve C57Bl/6 mice. Chlorhexidine gluconate (CG) was injected intraperitoneally to induce PF. Immunohistochemical analysis was performed with parietal peritoneum using anti-Sca-1 or -c-Kit and -GFP antibodies. Isolated BM cells were also transplanted into the CG-stimulated peritoneum. BM-derived cells from GFP transgenic mice appeared in the submesothelium from days 14 to 42. Both GFP- and stem cell marker-positive cells were observed in the submesothelium and on the surface. Isolated c-Kit-positive cells, transplanted into the peritoneal cavity, differentiated into mesothelial cells. In this study, we investigated whether or not BM-derived cells play a role in the repair of PF and immature cells have the potential of inducing repair of the peritoneum. The findings of this study suggest a new concept for therapy of PF.
    Journal of Artificial Organs 05/2012; 15(3):272-82. · 1.41 Impact Factor
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    ABSTRACT: Background/Purpose Recovery from peritoneal fibrosis (PF) involves the digestion of accumulated collagens and remodeling. Matrix metalloproteinases (MMPs) may play an important role in repair. The role of MMP-13, an important component in the MMP cascade, in PF is still unclear. We examined the sequential expression of MMP synthesis during repair in a PF mouse. Methods Forty-eight mice at 8 weeks of age were given an intraperitoneal injection of 0.1% chlorhexidine gluconate (CG) for 3 weeks. Control mice were injected with the same dosages of 15% ethanol dissolved in saline. These mice were sacrificed, and anterior abdominal walls were obtained on days 21, 28, 35, 42, 49, and 56. Gene expressions of MMP-2 and -13, tissue inhibition of metalloproteinase-1 (TIMP-1) and -2, MT1-MMP, transforming growth factor-beta 1, and collagen types I and III were analyzed by real-time polymerase chain reaction. MMP-13 enzyme activity was also measured. In immunohistological evaluation, MMP-13 expressing cells were examined. Results Thickening of the peritoneum and marked infiltration of monocytes were induced by CG, and the alterations remained until 7 days after cessation of CG. Then tissue repair rapidly advanced. Synthesis of collagen types I and III, MMP-2, TIMP-1 and -2, and transforming growth factor-beta 1 in the injured peritoneum was significantly increased until day 28. These increments were preceded by an increase of MMP-13 synthesis and activity after cessation of CG. Some infiltrating macrophages in the thickened peritoneum showed MMP-13 expression early after cessation of CG. Conclusion MMP-13 was synthesized by infiltrating monocytes early in the repair process in the CG-induced PF mouse. After cessation of stimulant, increase of MMP-13 synthesis may act as an inducer of an efficient degradation cascade in collagen-rich peritoneal tissue. 背景 腹膜纖維化的復原涉及膠原蛋白堆積的消化與其後的重塑,其中,基質金屬蛋白酶(MMPs)在組織修復期間可能佔有重要的角色。作為MMP級聯中的重要一環,MMP-13在腹膜纖維化上的角色仍然未明。本研究透過腹膜纖維化(PF)的小鼠,調查了在腹膜修復期間MMP生成的表現順序。 方法 研究材料為48隻年齡8週的小鼠,先接受每天共3週的0.1%葡萄糖酸氯己定(CG)腹膜內注射;另外對照組的注射則採用相同容量or劑量含15%乙醇的鹽水。其後陸續宰殺小鼠以取得第21、28、35、42、49及56天的前腹壁檢體,並採用實時PCR測量以下的基因表現:MMP-2-13、TIMP-1-2、MT1-MMP、TGF-β(1)、及I III型膠原蛋白。此外亦同時測量MMP-13之酵素活動,並對表現MMP-13的細胞作免疫組織學評估。 結果 在CG誘導下,可見腹膜增厚及單核球的明顯浸潤,直至停止CG後7天,其後可見組織修復的快速進行。在停止CG後的受損腹膜中,首先可見MMP-13生成與活動的增加,其後亦可見I III型膠原蛋白、MMP-2、TIMP-1-2、及TGF-β(1)生成的明顯增加,直至第28天。在停止CG後的早期,可見增厚腹膜中有若干巨噬細胞具MMP-13表現。 結論 在CG所致的PF小鼠中,腹膜修復早期已可見浸潤的單核球產生MMP-13。在停止刺激後,在富含膠原蛋白的腹膜環境中,MMP-13似乎可促使一個高效降解級聯的進行。
    Hong Kong Journal of Nephrology 04/2012; 14(1):7–16.
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    ABSTRACT: The activity of gelatinase, matrix metalloproteinase-2, in effluent was increased in peritoneal dialysis patients with encapsulated peritoneal sclerosis (EPS) and in chlorhexidine gluconate-induced peritoneal sclerosing (PS) animal models. The objective of the present study was to investigate the effect of matrix metalloproteinase inhibitor (ONO-4817), an anticancer agent with anti-angiogenesis and anti-infiltration effects, on the development of peritoneal fibrosis in chlorhexidine gluconate-induced PS rats. Forty-five Sprague-Dawley (S-D) rats were intraperitoneally injected with saline as control (n = 15) or with chlorhexidine gluconate (CH) (1.5 ml/100 g) in the CH group (n = 15). ONO-4817 (5 mg/rat) was administered intravenously to CH rats (the ONO-4817 group, n = 15) from initiation to the end of the study. After 22 days of ONO-4817 administration, the rats were sacrificed and the parietal peritoneum was harvested. The gene expressions of transforming growth factor-beta (TGF-beta), alpha-smooth muscle actin (alpha-SMA) and type I collagen in the peritoneum were analysed by the reverse transcription-polymerase chain reaction (RT-PCR). Peritoneal tissues were also evaluated immunohistologically. ONO-4817 significantly inhibited thickening of the submesothelial layer and accumulation of type I collagen in the peritoneum. ONO-4817 also prevented increases of the number of macrophages and blood vessels. The expressions of TGF-beta, alpha-SMA and type I collagen in the peritoneum were markedly suppressed in ONO-4817-treated rats. It appears that the administration of the MMP inhibitor ONO-4817 might be a new approach to the amelioration of PS.
    Nephrology Dialysis Transplantation 11/2007; 22(10):2838-48. · 3.37 Impact Factor
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    ABSTRACT: It is well known that injection of calcitriol (CT) or maxacalcitol (OCT) is very effective in hemodialysis patients with secondary hyperparathyroidism (2HPT). However, it is difficult to use these drugs with peritoneal dialysis (PD) patients with 2HPT because these drugs must be injected two or three times per week. The objective of the present study was to evaluate the stability of physiological activities of CT and OCT in PD bags and to determine the CT or OCT dosage for intraperitoneal (IP) administration. We added CT 1.5 microg or OCT 10 microg to Dianeal PD-2 (approximate pH = 5.0, calcium = 0.87 mmol/L; Baxter,Tokyo, Japan), Midpeliq 250 (approximate pH = 7.0, Ca = 1.0 mmol/L;Terumo Corporation, Tokyo, Japan), and Peritoliq 250 (approximate pH = 5.5, Ca = 1.0 mmol/L; Terumo Corp.). Dialysis solutions were collected from the PD bags at 0, 1, 4, 8, 12, 24, 48, and 72 hours after addition of CT and OCT. The activities of CT and OCT in the dialysis effluent were measured by radioimmunoassay. The levels of serum and effluent OCT after a single IP administration of 10 microg OCT were examined in 4 PO patients with advanced 2HPT. Although the levels of CT and OCT in PD bags made of polyvinyl resins decreased by 70% - 75% immediately after injection, levels in PD bags made of polypropylene resins decreased only slightly. The concentration of CT mixed into the acidic solution in glass containers was stable; the decreased concentration of CT in the PD solution might be due to adsorption onto polyvinyl resins. The maximum serum concentration after IP administration of 10 microg OCT was 750 pg/mL after 5 minutes, and remained at 500 pg/mL at 60 minutes. These results show good peritoneal transport of OCT but not rapid disappearance, unlike intravenous administration. If peritoneal administration of vitamin D derivatives is contemplated, it is important to select the composition of PD bag resins, type of vitamin D analog, and time lag to use when deciding the dosage of injectable vitamin D preparations, such as OCT or CT, for IP administration to PD patients. It appears that IP administration in overnight dwells might be useful for PD patients as a complementary vitamin D preparation.
    Peritoneal dialysis international: journal of the International Society for Peritoneal Dialysis 25(6):570-5. · 2.21 Impact Factor