Chieko Hamada - Academia.edu (original) (raw)

Papers by Chieko Hamada

Journal of Bone and Mineral Research

Journal of Bone and Mineral Research, 2009

The effect of heparin on osteoclastic bone resorption was studied in vitro using the disaggregate... more The effect of heparin on osteoclastic bone resorption was studied in vitro using the disaggregated osteoclast resorption assay. Bone resorption was assessed by counting the resorption lacunae on bone slices by light microscopy. Low concentrations of heparin (5 μg/ml) increased bone resorption by isolated chick and rat osteoclasts. Among other glycosaminoglycans tested at 5 μg/ml, only dextran sulfate showed a small but significant stimulation of resorption. Chondroitin sulfates A, B, and C were without effect at 25 and 100 μg/ml, whereas resorption was increased by 100 μg/ml of heparan sulfate. With chick osteoclasts, which could be maintained in serum‐free conditions, a stimulatory effect of heparin was found both in the presence of 5% fetal calf serum and in serum‐free media containing insulin, transferrin, and selenium. The magnitude of the heparin‐induced increase in resorption was similar in the presence or absence of serum. The stimulation of resorption was associated with an ...

Nephron, 1990

Plasma immunoreactive human atrial natriuretic peptide (hANP) levels were measured in 9 patients ... more Plasma immunoreactive human atrial natriuretic peptide (hANP) levels were measured in 9 patients with chronic renal failure treated with maintenance hemodialysis in order to evaluate the effects of fluid removal and osmotic pressure. Under hemodialysis without fluid removal plasma hANP levels remained unchanged, but the levels were significantly decreased during extra-corporeal ultrafiltration (p less than 0.01). The present study provided strong evidence that the fall in plasma hANP levels in hemodialysis patients is mainly due to the reduction in circulating plasma volume.

Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis, 2007

Peritoneal fibrosis (PF) is invariably observed in patients undergoing long-term peritoneal dialy... more Peritoneal fibrosis (PF) is invariably observed in patients undergoing long-term peritoneal dialysis (PD). The condition is thought to occur in response to a variety of insults, including bioincompatible dialysates (acidic solution, high glucose, glucose degradation products, or a combination), peritonitis, uremia, and chronic inflammation. Recently, the pathophysiologic mechanisms that contribute to the fibrosing process have been intensively studied. Transforming growth factor-β has been shown to be a key mediator of PF. Loss of the mesothelial cell layer has been identified in several studies and shown to correlate with submesothelial thickening and vasculopathy. An association has also been identified between increased submesothelial thickness in the peritoneal membrane and increased solute transport, suggesting a relationship between PF and loss of ultrafiltration capacity. Thus, to maintain long-term PD and improve quality of life for patients, it is important to develop inter...

Renal Replacement Therapy, 2020

The annual survey of the Japanese Society for Dialysis Therapy Renal Data Registry (JRDR) was sen... more The annual survey of the Japanese Society for Dialysis Therapy Renal Data Registry (JRDR) was sent to 4458 dialysis facilities at the end of 2018; among these facilities, 4402 facilities (98.7%) responded to the facility questionnaire, and 4222 (94.7%) responded to the patient questionnaire. The number of chronic dialysis patients in Japan continues to increase every year; as of the end of 2018, it had reached 339,841 patients, representing 2688 patients per million population. Among the prevalent dialysis patients, the mean age was 68.75 years, and diabetic nephropathy was the most common primary disease among the prevalent dialysis patients (39.0%), followed by chronic glomerulonephritis (26.8%) and nephrosclerosis (10.8%). The number of incident dialysis patients was 40,468, and a reduction by 491 from 2017. The mean age of the incident dialysis patients was 69.99 years old. Diabetic nephropathy was also the most common primary disease (42.3%), representing a 0.2 percent point re...

Scientific Reports, 2020

The ability to visualize intraluminal surface of peritoneal dialysis (PD) catheter and peritoneal... more The ability to visualize intraluminal surface of peritoneal dialysis (PD) catheter and peritoneal cavity could allow elucidation of the cases of outflow problems, and provide information on changes to the peritoneal membrane leading to encapsulating peritoneal sclerosis. A non-invasive examination that allows those monitoring in need is desirable. We have developed a disposable ultra-fine endoscope that can be inserted into the lumen of the existing PD catheter, allowing observation of the luminal side of the catheter and peritoneal cavity from the tip of the PD catheter, with minimum invasion in practice. In a pre-clinical study in pigs and a clinical study in 10 PD patients, the device provided detailed images, enabling safe, easy observation of the intraluminal side of the entire catheter, and of the morphology and status of the peritoneal surface in the abdominal cavity under dwelling PD solution. Since this device can be used repeatedly during PD therapy, clinical application o...

Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis, 2005

ObjectivesIt is well known that injection of calcitriol (CT) or maxacalcitol (OCT) is very effect... more ObjectivesIt 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.Materials and MethodsWe added CT 1.5 μg or OCT 10 μg 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...

PLOS ONE, 2017

Background High glucose concentrations influence the functional and structural development of the... more Background High glucose concentrations influence the functional and structural development of the peritoneal membrane. We previously reported that the oral administration of astaxanthin (AST) suppressed peritoneal fibrosis (PF) as well as inhibited oxidative stress, inflammation, and epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) in a chlorhexidine-induced PF rat model. This suggests that oxidative stress induction of EMT is a key event during peritoneal damage. The present study evaluated the therapeutic effect of AST in suppressing EMT, in response to glucose-induced oxidative stress. Methods Temperature-sensitive mesothelial cells (TSMCs) were cultured in the presence or absence of AST and then treated with 140 mM glucose for 3 or 12 hours. Expression levels of TNF-α, TGF-β, and VEGF were determined at the mRNA and protein levels, and nuclear factor kappa B (NF-κB) activity was evaluated. We measured NO 2 − /NO 3 − concentrations in cellular supernatants and determined 8-hydroxy-2 0-deoxyguanosine (8-OHdG) levels in mitochondrial and nuclear DNA. The expressions of E-cadherin and alpha-smooth muscle actin (α-SMA) were evaluated by double immunofluorescence and protein levels. Results High glucose concentrations induced overproduction of reactive oxidative species (ROS), increasing 8-OHdG mitochondrial DNA and cytokine levels. The NF-κB pathway was activated in response to high glucose concentrations, whereas de novo α-SMA expression was observed with decreased E-cadherin expression. AST treatment attenuated ROS production, inflammatory cytokine production, NF-κB activation, and EMT.

Journal of Japanese Society for Dialysis Therapy, 1990

Nihon Toseki Igakkai Zasshi, 1998

Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis, Jan 7, 2014

♦ Background: Preventing peritoneal damage during peritoneal dialysis is critical. Reactive oxyge... more ♦ Background: Preventing peritoneal damage during peritoneal dialysis is critical. Reactive oxygen species (ROS) have an important role in peritoneal damage; however, few studies have investigated this. We aimed to determine the effects of oral astaxanthin (AST) supplementation in a peritoneal fibrosis (PF) rat model. ♦ Methods: Thirty-seven Sprague-Dawley rats were divided into 5 groups: Control 1 (fed a normal diet without stimulation), Control 2 (fed an AST-supplemented diet without stimulation), Group 1 (fed a normal diet with 8% chlorhexidine gluconate [CG] stimulation for 3 weeks), Group 2 (fed a 0.06% AST-supplemented diet with CG stimulation), and Group 3 (fed a 0.06% AST-supplemented diet that was initiated 4 weeks before CG stimulation). Peritoneal fibrosis, vascular proliferation, and fibrosis-related factor expression were examined. ♦ Results: Peritoneal thickness was significantly suppressed by AST supplementation. Astaxanthin diminished the number of CD68-, 8-hydroxy-2...

Nephron extra, 2012

Previous studies have shown the presence of high levels of glycoxidation and lipid peroxidation p... more Previous studies have shown the presence of high levels of glycoxidation and lipid peroxidation products in association with atherosclerosis in patients with end-stage kidney disease. Acetates are commonly used buffer for correcting metabolic acidosis in hemodialysis (HD) patients. Since the toxic effects of acetates are well established, acetate-free citrate dialysate (AFD) has become available in Japan. The objective of the present study was to evaluate the suppressive effects of AFD on oxidative stress in maintenance HD patients by measuring plasma pentosidine and malondialdehyde-modified low-density lipoprotein (MDA-LDL) levels as markers for glycoxidation and lipid peroxidation products. Plasma pentosidine, MDA-LDL and other laboratory parameters were examined on maintenance HD at the Juntendo University Hospital before and after switching to AFD. MDA-LDL levels divided by LDL cholesterol were significantly lower than those before switching to AFD. Furthermore, levels of plasma...

Journal of artificial organs : the official journal of the Japanese Society for Artificial Organs, 2013

It is well known that bioincompatible peritoneal dialysate plays a central role in the developmen... more It is well known that bioincompatible peritoneal dialysate plays a central role in the development of peritoneal fibrosis. Peritoneal inflammation continues even after the cessation of peritoneal dialysate stimulation. It is important to establish the definition of persistent inflammation in the peritoneal cavity at the cessation of peritoneal dialysis (PD). The objective of the present study was to determine whether pentraxin 3 (PTX3) in peritoneal effluent (PE) may be a new biomarker in PD patients. Serum, PE, and peritoneal specimens were obtained from 50 patients with end-stage kidney disease at Juntendo University Hospital. Samples of 19 patients were obtained at the initiation of PD and those of 31 patients at the cessation of PD. PTX3, high-sensitivity CRP, and MMP-2 and IL-6 were analyzed. An immunohistological examination using an anti-PTX3 antibody was performed. Expressions of PTX3 were observed in endothelial cells, fibroblasts, and mesothelial cells in the peritoneum. T...

Journal of Artificial Organs, 2012

Marked thickening of the peritoneum and vasculopathy in the submesothelial compact zone have been... more 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.

Juntendo Medical Journal, 2007

Seminars in Dialysis, 2013

Peritoneal dialysis (PD) catheters often become severely dislocated, which may lead to malfunctio... more 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 conventi...

Planta Medica, 2002

Sodium spirulan (Na-SP) is a sulfated polysaccharide isolated from the blue-green alga Spirulina ... more Sodium spirulan (Na-SP) is a sulfated polysaccharide isolated from the blue-green alga Spirulina platensis, which consists of two types of disaccharide repeating units, O-hexuronosyl-rhamnose (aldobiuronic acid) and O-rhamnosyl-3-O-methylrhamnose (acofriose) with sulfate groups, other minor saccharides and sodium ion. Vascular endothelial cells are present on the inner surface of blood vessels in a monolayer and have anticoagulant properties. To address the question whether Na-SP influences the maintenance of endothelial cell monolayers, we investigated the proliferation of cultured bovine aortic endothelial cells treated with Na-SP. It was found that Na-SP has an inhibitory activity on endothelial cell proliferation accompanied with suppression of whole protein synthesis but without non-specific cell damage. The inhibitory activity of Na-SP was the strongest when compared to that of heparan sulfate, heparin, dextran sulfate, dermatan sulfate, chondroitin sulfate A/C and hyaluronan. Furthermore, it was shown that the inhibitory activity of Na-SP disappeared by either desulfation or depolymerization. The present data suggest that Na-SP is a unique sulfated polysaccharide that strongly inhibits vascular endothelial cell proliferation, and the inhibitory activity requires polymerization of sulfated O-rhamnosyl-acofriose repeating units.

Nephrology, 2003

SUMMARY: Secondary hyperparathyroidism (2HPT), which is related to renal osteodystrophy (ROD), m... more SUMMARY: Secondary hyperparathyroidism (2HPT), which is related to renal osteodystrophy (ROD), may occur in patients in the comparatively early stage of chronic renal failure (CRF). Secondary hyperparathyroidism patients with parathyroid hyperplasia showed resistance to vitamin D3 treatment during long‐term dialysis. At present, evaluation by ultrasonography is considered to be useful for confirming parathyroid hyperplasia. There are no clinical data associated with imaging evaluation of 2HPT in CRF patients. In the present study, the relationship among clinical and biochemical data, and parathyroid hyperplasia by ultrasonography, was evaluated in 12 patients (six males and six females) with end‐stage renal failure (ESRF) before and at initiation of dialysis. Five patients showed an enlargement of parathyroid glands in ultrasonography. Levels of serum‐intact parathyroid hormone (PTH) in patients with parathyroid hyperplasia (positive group) were significantly higher than in those w...

Life Sciences, 2002

Calcium spirulan (Ca-SP) is a novel sulfated polysaccharide isolated from a blue-green alga Spiru... more Calcium spirulan (Ca-SP) is a novel sulfated polysaccharide isolated from a blue-green alga Spirulina platensis. Ca-SP inhibits thrombin by activation of heparin cofactor II. Therefore, it could serve as an origin of anti-atherogenic medicines. Since maintenance of vascular endothelial cell monolayers is important for prevention of vascular lesions such as atherosclerosis, the effect of Ca-SP at 20 mg/ml or less on the repair of wounded bovine aortic endothelial cell monolayers in culture was investigated in the present study. When the monolayers were wounded and cultured in the presence of Ca-SP, the polysaccharide inhibited the appearance of the cells in the wounded area. The inhibition was also observed even when the repair was promoted by excess basic fibroblast growth factor, which is one of the autocrine growth factors that are involved in the endothelial cell monolayer maintenance. On the other hand, Ca-SP inhibited the cell growth and the incorporation of [ 3 H]thymidine into the acidinsoluble fraction of proliferating endothelial cells, suggesting that Ca-SP inhibits endothelial cell proliferation. From these results, it is concluded that Ca-SP may retard the repair process of damaged vascular endothelium through inhibition of vascular endothelial cell proliferation by induction of a lower ability to respond to stimulation by endogenous basic fibroblast growth factor.