Serum Magnesium Levels and Mortality in Japanese Maintenance Hemodialysis Patients.

BACKGROUND/AIMS: Although hypomagnesemia was found to be a risk for cardiovascular diseases in the general population, the relationship between serum magnesium (Mg) levels and prognosis of patients on maintenance hemodialysis (MHD) has not been extensively studied. This study sought to determine the relationship of serum Mg levels with aortic arch calcification (AoAC) and mortality in Japanese MHD patients. METHODS: We measured serum Mg levels in a cohort of 392 patients on MHD, classified the patients into 3 groups according to these levels, and followed their course for 4 years. AoAC was assessed using chest-X-rays. RESULTS: During follow-up, there were 117 deaths. Kaplan-Meier analyses showed that the high serum Mg group tended to have better survival rates than the low and middle serum Mg groups but this did not reach statistical significance. We also found that patients in the high serum Mg group had better nutritional status associated with higher serum albumin, triglyceride, and phosphate levels and had a significantly lower serum C-reactive protein level. In total, 83 patients (59.3%) in the high serum Mg group had been prescribed Mg oxide (MgO). CONCLUSIONS: Hypermagnesemia tended to be associated with better survival and a higher prescription rate of MgO. Interventional studies are needed to clarify whether Mg supplementation is beneficial for improving patient prognosis.

Association Between Risk Factors Including Bone-Derived Biomarkers and Aortic Arch Calcification in Maintenance Hemodialysis Patients.

BACKGROUND/AIMS: Aortic arch calcification (AoAC) is frequently detected in maintenance hemodialysis (MHD) patients and is associated with cardiovascular and all-cause mortality. We investigated the factors associated with AoAC and analyzed the relationship between the factors including bone-derived biomarkers and AoAC. METHODS: We enrolled 389 stable MHD patients. AoAC was assessed using chest-X ray examination. Demographic data was collected in addition to serum levels of biochemical and bone-derived biomarkers, including sclerostin and fibroblast growth factor-23 (FGF-23). RESULTS: Two hundred sixteen patients (55.5%) had AoAC. Patients with AoAC score ≥ 4 were older, with a higher percentage being male, and exhibited lower serum levels of albumin and triglyceride. Serum FGF-23 levels were inversely associated with AoAC severity, and FGF-23was directly related to vascular calcification. Age, gender, and dialysis vintage were independent predictors of AoAC. CONCLUSION: MHD patients have a high prevalence of AoAC. The grade of AoAC was dependent on older age in association with longer dialysis vintage. Levels of circulating FGF-23 but not sclerostin were related to AoAC severity. Serum FGF-23 levels were independently associated with AoAC.

Geriatric Nutritional Risk Index Is a Simple Predictor of Mortality in Chronic Hemodialysis Patients.

BACKGROUND: Malnutrition is common in hemodialysis (HD) patients, and it is associated with increasing risk of mortality. The geriatric nutritional risk index (GNRI) has been developed as a tool to assess the nutritional risk. The aim of this study was to examine the reliability of the GNRI as a mortality predictor in a Japanese HD cohort. METHODS: We prospectively examined the GNRI of 332 maintenance HD patients aged 65.4 ± 13.2, 213 males, and followed up on them for 36 months. The patients were divided into quartiles (Q) according to GNRI values (Q1: <91.6, Q2: 91.7-97.0, Q3: 97.1-102.2, Q4: >102.3). Predictors for all-cause mortality were examined using Kaplan-Meier and Cox proportional-hazards analyses. RESULTS: The GNRI presented a normal distribution. During the follow-up period of 36 months, 76 patients died. The overall mortality at the end of the 3-year observational period was 22.3%. At the 3-year follow-up period, Kaplan-Meier survival rates for all-cause mortality were 72.3, 79.3, 84.9 and 92.6% in Q1, Q2, Q3, and Q4, respectively (p = 0.0067). Multivariate Cox proportional-hazards analysis demonstrated that the GNRI was a significant predictor of adjusted all-cause mortality (HR 0.958; 95% CI 0.929-0.989, p = 0.0073). CONCLUSIONS: The results of the present study demonstrate that the GNRI is a strong predictor of overall mortality in HD patients. However, cardiovascular mortality was not associated with GNRI values, and did not differ among the GNRI quartiles. The GNRI score can be considered a simple and reliable marker of predictor for mortality risk in Japanese HD patients.

Relationship between anaemia management at haemodialysis initiation and patient prognosis.

AIM: It has been suggested that anaemia management during a transition period to haemodialysis could influence prognosis. In this paper, we have conducted a retrospective investigation on how Hb levels at haemodialysis initiation in patients with chronic kidney disease (CKD) influence the risk of cerebral infarction and cardiovascular events. METHODS: Seventy-two patients who underwent initial haemodialysis between May 2012 and April 2014 were designated as subjects of the study and the patients were divided into a cohort with Hb levels ≥8 g/dL and a cohort with <8 g/dL at haemodialysis initiation. The occurrence of cardiovascular events was analyzed using the Kaplan-Meier method and Cox proportional hazards model. RESULTS: The cohort with <8 g/dL Hb levels at haemodialysis initiation demonstrated a tendency toward low dosage of ESA or iron preparation in the pre-haemodialysis (maintenance) phase. Significant incidence of cardiovascular (log rank, P = 0.002) and cerebrovascular (log rank, P = 0.02) events was observed. The results of multivariate analysis of the Cox proportional hazards model indicated that anaemia with <8 g/dL Hb levels at haemodialysis initiation was a significant risk factor for coronary artery (hazard ratio = 12.85, P = 0.003) and cerebrovascular (hazard ratio = 5.11, P = 0.04) diseases post-haemodialysis. CONCLUSION: The results of this investigation indicate the possible involvement of low Hb levels at haemodialysis initiation as a factor in cardio- and cerebrovascular events. There, our results suggested that the administration of adequate dosage of iron preparations and ESA in the pre-haemodialysis period could help prevent cardio- and cerebrovascular events.

Aortic arch calcification predicts cardiovascular and all-cause mortality in maintenance hemodialysis patients.

BACKGROUND/AIM: Vascular calcification is associated with cardiovascular risk in maintenance hemodialysis (MHD) patients. Previous reports have shown that simple assessment of aortic arch calcification (AoAC) using plain radiography is associated with cardiovascular mortality in the general population. We conducted a prospective study to investigate factors associated with the presence at baseline and progression of AoAC in MHD patients and examined its prognostic value in a short-term outcome. METHODS: We prospectively evaluated chest X-rays in 301 asymptomatic MHD patients. The extent of AoAC was divided into three Grades (0, 1, 2+3). Demographic data including age, gender, dialysis vintage, co-morbidity and biochemical data were assessed and the patients were then followed for 3 years. RESULTS: AoAC was observed in 126 patients (41.9%) as Grade 0, in 112 patients (37.2%) as Grade 1, and in 63 patients (20.9%) as Grade 2 and 3 at baseline. An increase in the severity of calcification was associated with older male patients who had lower serum albumin levels. During the follow-up period of 3 years, multivariate Cox proportional hazards analysis revealed that high-grade calcification was associated with cardiovascular and all-cause mortality. Patients with AoAC were associated with a worse outcome in survival analysis and the grade of AAC also influenced their survival. Moreover, all-cause death rates were significantly higher in the progression groups than in the non-progression groups. CONCLUSIONS: The presence and progression of AoAC assessed by chest X-ray were independently associated with mortality in MHD patients. Regular follow-up by chest X-ray could be a simple and useful method to stratify mortality risk in MHD patients.

Erythropoietin resistance index and the all-cause mortality of chronic hemodialysis patients.

BACKGROUND: Evidence suggests hemodialysis (HD) patients with resistance to erythropoiesis-stimulating agents (ESA) have a higher mortality rate. We investigated the association between ESA responsiveness and mortality in our HD population. METHODS: A prospective cohort study of chronic HD patients was conducted at Jyoban Hospital in Fukushima, Japan. We collected data on patient demographic factors, comorbidities, dialysis vintage, body weight, ESA dose and hemoglobin concentration, as well as data on known risk factors for ESA hyporesponsiveness. The erythropoietin resistance index (ERI) was calculated by dividing the weekly body-weight-adjusted epoetin dose by the hemoglobin concentration. The association between ESA hyporesponsiveness estimated by the highest tertile of ERI and mortality was investigated by using the Cox proportional hazards model with adjustments for demographic factors, comorbidities, dialysis adequacy and serum biochemical data. RESULTS: A total of 248 patients were included as subjects in the cohort, and their overall 2-year mortality rate was 13.3%. According to the results of the Kaplan-Meier analysis, patients with an ERI in the highest tertile had significantly higher mortality than patients with an ERI in the lower two tertiles (p = 0.0121). The highest ERI tertile was associated with higher all-cause mortality in both the unadjusted hazards model (hazard ratio, HR: 4.429; 95% CI: 1.249-15.704) and the adjusted hazards model (HR: 4.204; 95% CI: 1.173-15.065). CONCLUSIONS: A higher degree of resistance to ESA in chronic HD patients is associated with increased mortality.

Whole mitochondrial genome sequencing and transcriptional analysis to uncover an RT102-type cytoplasmic male sterility-associated candidate Gene Derived from Oryza rufipogon.

Cytoplasmic male sterility (CMS) is a maternally inherited trait in which plants fail to produce functional pollen and is associated with the expression of a novel open reading frame (orf) gene encoded by the mitochondrial genome. An RT102A CMS line and an RT102C fertility restorer line were obtained by successive backcrossing between Oryza rufipogon W1125 and O. sativa Taichung 65. Using next-generation pyrosequencing, we determined whole-genome sequences of the mitochondria in RT102-CMS cytoplasm. To identify candidates for the CMS-associated gene in RT102 mitochondria, we screened the mitochondrial genome for the presence of specific orf genes that were chimeric or whose products carried predicted transmembrane domains. One of these orf genes, orf352, which showed different transcript sizes depending on whether the restorer of fertility (Rf) gene was present or not, was identified. The orf352 gene was co-transcribed with the ribosomal protein gene rpl5, and the 2.8 kb rpl5-orf352 transcripts were processed into 2.6 kb transcripts with a cleavage at the inside of the orf352 coding region in the presence of the Rf gene. The orf352 gene is an excellent candidate for the CMS-associated gene for RT102-CMS.

Citric acid-based bicarbonate dialysate attenuates aortic arch calcification in maintenance hemodialysis patients: a retrospective observational study.

BACKGROUND: Progression of aortic calcification is associated with all-cause and cardiovascular mortality in hemodialysis patients. Blood calciprotein particle (CPP) levels are associated with coronary artery calcification and were reported to be inhibited when using citric acid-based bicarbonate dialysate (CD). Therefore, this study aimed to examine the effect of CD on the progression of the aortic arch calcification score (AoACS) and blood CPP levels in hemodialysis patients. METHODS: A 12-month retrospective observational study of 262 hemodialysis patients was conducted. AoACS was evaluated by calculating the number of calcifications in 16 segments of the aortic arch on chest X-ray (minimum score is 0; maximum score is 16 points). The patients were divided into the following groups according to their baseline AoACS: grade 0, AoACS = 0 points; grade 1, AoACS 1-4 points; grade 2, AoACS 5-8 points; grade 3, AoACS 9 points or higher. Patients on bisphosphonates or warfarin or with AoACS grade 3 were excluded. Progression, defined as ΔAoACS (12-month score - baseline score) > 0 points, was compared between the CD and acetic acid-based bicarbonate dialysate (AD) groups before and after adjusting the background using propensity score matching. RESULTS: The AoACS progression rate was significantly lower in the CD group than in the AD group (before matching: P = 0.020, after matching: P = 0.002). Multivariate logistic regression analysis showed that CD was significantly associated with AoACS progression (odds ratio 0.52, 95% confidence interval 0.29‒0.92, P = 0.025). CONCLUSION: CD may slow the progression of vascular calcification in hemodialysis patients.

Detection of synthetic RGDS(PO3H2)PA peptide adsorption using a titanium surface plasmon resonance biosensor.

The purpose of this study was to measure the time-dependent chemical interaction between synthetic RGDS(PO(3)H(2))PA (P-RGD) peptide and titanium surfaces using a titanium surface plasmon resonance (SPR) biosensor and to determine the degree of peptide immobilization on the surfaces. An SPR instrument for 'single-spot' analysis was used for nanometer-scale detection of biomolecular adsorption using a He-Ne laser light according to Knoll's method. The oxidized titanium surface was etched when exposed to H(3)PO(4) solutions with a pH of 2.0 or below. The amount of P-RGD adsorbed at pH 1.9 was approximately 3.6 times as much as that at pH 3.0 (P < 0.05). P-RGD naturally adsorbed on the oxidized titanium surface as a consequence of the bonding and dissociation mechanism of the phosphate functional group. Furthermore, the control of pH played a very important role in the interaction between P-RGD and the surface. These findings show that pH control may promote progressive binding of biomolecules with the phosphate functional group to the titanium surface.

Creation of highly functional CO3Ap-collagen scaffold biomaterials.

Physicochemical properties of apatites are affected dramatically by the substitution of trace elements. Especially, biological apatites constituting bone and teeth contain several wt% of CO(3)(2- )ions, which are related to the crystallinity and solubility. Recently, scaffold biomaterials are being developed with a shape-maintaining property in addition to large pores and high porosity, into which cells can easily invade. To develop a new biodegradable scaffold biomaterial, bone-like carbonate apatites (CO(3)Ap) were synthesized and CO(3)Ap-collagen scaffolds were created. This scaffold biomaterial is useful for regions with bone regeneration ability. When these sponge-frame complexes with rh-BMP2 were implanted beneath the periosteum cranii of rats, sufficient new bone was created at the surface of the periosteum cranii after 4 weeks' implantation. Furthermore, when a CO(3)Ap-collagen sponge containing SVVYGLR peptide was implanted as a graft into a tissue defect created in rat tibia, the migration of numerous vascular endothelial cells, as well as prominent angiogenesis inside the graft, could be detected after 1 week. Thus, the modification of higher functions such as cytokine and angiogenesis factors is effective for low regeneration regions using tissue engineering biomaterials.

Effects of high-dose major components in oral disinfectants on the cell cycle and apoptosis in primary human gingival fibroblasts in vitro.

We evaluated the effects of high-dose major components in oral disinfectants on oral cells from the standpoints of the cell cycle and apoptosis. We examined the viability and cell cycle of human gingival fibroblasts (HGFs) treated with the components of dental disinfectants, benzethonium chloride (BEC), benzalkonium chloride (BAC), and povidone iodine (PVD-I) using a cell counting kit and flow cytometry. The IC(50) inhibitory concentration value in HGF cultures at 24 hours was 1.3x10(-2) mM BEC, 6.0x10(-3) mM BAC, and 2.6x10(-1) mM PVD-I. In the cell cycle analysis, propidium iodide-stained HGFs were arrested in G(0)/G(1) of the cell cycle by all three disinfectants, and in the apoptosis assay, annexin V-FITC/PI-stained HGFs that became apoptotic at 5.0x10(-2) and 1.0x10(-1) mM BEC and 5.0x10(-2) and 1.0x10(-1) mM BAC, but not in PVD-I at concentrations as high as 5.0x10(-1) mM. Our findings describe the effects of high-dose oral disinfectants, rather than clinical concentrations. Nevertheless, appreciating the effects of high-dose disinfectants absorbed into the human body is important, where they may accumulate in specific tissues and cells.

Bone formation ability of carbonate apatite-collagen scaffolds with different carbonate contents.

Hydroxyapatite and carbonate apatites with different carbonate contents were synthesized, mixed with atelocollagen, and made into sponge scaffolds. The scaffolds were implanted into the bone sockets of the femurs of male New Zealand white rabbits for 2, 3, 12 and 24 weeks. carbonate apatite-collagen scaffold with 4.8 wt% carbonate content appeared to have similar crystallinity and chemical composition to human bone. When the scaffolds were implanted into the rabbit femurs, histological observation indicated that the carbonate apatites-collagen scaffolds with relatively higher carbonate contents were gradually deformed throughout the implantation period, and showed uniform surrounding bone after 24 weeks and could not be distinguished. The carbonate apatite-collagen scaffold with 4.8 wt% carbonate content showed the highest bone area ratio of all of the scaffolds. It is suggested that a carbonate apatite-collagen scaffold with carbonate content similar to that of human bone may have optimal bone formation ability.

Influence of chlorine dioxide on cell death and cell cycle of human gingival fibroblasts.

OBJECTIVES: The effects of chlorine dioxide (ClO2), sodium hypochlorite (NaOCl), and hydrogen peroxide (H2O2) on cell death and the cell cycle of human gingival fibroblast (HGF) cells were examined. METHODS: The inhibition of HGF cell growth was evaluated using a Cell Counting Kit-8. The cell cycle was assessed with propidium iodide-stained cells (distribution of cells in G0/G1, S, and G2/M phases) using flow cytometry. The patterns of cell death (necrosis and apoptosis) were analyzed using flow cytometry with annexin V-FITC/PI staining. RESULTS: The lethal doses for 50% of the cells (LD50) of ClO2, NaOCl, and H2O2 were 0.16, 0.79, and 0.11 mM, respectively. All three dental disinfectants induced G0/G1 cell cycle arrest. H2O2 induced apoptosis at concentrations of 0.05 and 0.1 mM, while NaOCl and ClO2 did not induce significant apoptosis at any concentration examined. CONCLUSIONS: These results suggest that ClO2 is sufficient for use as a dental disinfectant compared with H2O2 or NaOCl.

Effect of ozonated water on the surface roughness of dental stone casts.

Infection control of dental stone cast is an important issue. Ozone is effective for disinfection against microorganisms and inactivation of viruses. However, there is little information regarding the use of ozone. We prepared 4 types of gypsum specimens and 3 types of disinfectants (4-5 ppm Ozonated water [OZW], 2% glutaraldehyde [GL], and 1% sodium hypochlorite [SH]). Gypsum specimens were immersed in each disinfectant for 5 and 10 min, and surface roughness was then examined using laser scanning microscopy. Surface microstructure was investigated using scanning electron microscopy. Immersion of gypsum specimens in SH, GL, and OZW increased the surface roughness to a maximum of 1.04, 0.37, and 0.30 µm, respectively, based on the difference between the average values of surface roughness before and after the disinfection procedure. The effects of OZW and GL were comparable. OZW is useful as a candidate for relatively safe disinfection of material for dental stone casts.

Association between Increases in Normalized Protein Catabolic Rate and Increases in Creatinine Generation Rate in Dialysis Patients.

The older dialysis population is growing, and malnutrition and wasting syndrome are great concerns in this population. The management of these syndromes includes appropriate nutritional intake and physical activity. However, whether management in the form of an increase in protein intake has a beneficial effect on muscle mass has not been demonstrated. In this study, we investigated an association between changes of normalized protein catabolic rate (nPCR), as a proxy for protein intake and percent creatinine generation rate (%CGR), as a proxy for muscle mass in patients receiving hemodialysis. Multiple linear regression models were employed, and we included several sensitivity analyses. The results showed that increases in nPCR were associated with increases in %CGR. The association was stronger in patients with baseline %CGR levels below 100%. This was the first study to demonstrate that an increase in dietary protein intake might increase the muscle mass, but this study had certain limitations. Future interventional studies will be needed to investigate whether increases in protein intake have a beneficial effect on sarcopenia, protein-energy wasting, and frailty.

Cell adhesion and proliferation patterns on mixed self-assembled monolayers carrying various ratios of hydroxyl and methyl groups.

Mixed self-assembled monolayers (SAMs) with hydroxyl and methyl surface groups were prepared as biomaterial surface models which were well-controlled and well-defined. The surface properties of mixed SAMs were examined by X-ray photoelectron spectroscopy and water contact angle measurement. It was found that the parameter of water contact angle more accurately reflected the surface compositions of mixed SAMs than by the mixing ratio of the two alkanethiols. Cell adhesion and growth were also examined on mixed SAMs of various wettability conditions. It was found that amount of serum protein adsorption changed with the surface composition. To examine the effect of surface composition on cell growth pattern, four cell types--C3H10T1/2-clone 8, L929, UVB6-2.1A, and MC3T3E1--were incubated on mixed SAMs for three or six days. Differences in cell growth pattern against wettability were clearly recognized for each cell type. In light of the results obtained in this study, the relationship between the biocompatibility of biomaterials and surface factors were thus clarified.

Apoptotic and necrotic influence of dental resin polymerization initiators in human gingival fibroblast cultures.

The aim of this study was to examine the apoptotic and necrotic influence of four dental resin polymerization initiators--namely benzoyl peroxide (BPO), camphorquinone (CQ), dimethylaminoethyl methacrylate (DMAEMA), and dimethyl-para-toluidine (DMPT)--on human gingival fibroblast (HGF) cells. To this end, the growth inhibition of HGF cells with 1 mM BPO, CQ, and DMAEMA, and 500 microM DMPT was evaluated using Cell Counting Kit-8. Then, cell cycle analysis by flow cytometry was used to assess propidium iodide-stained cells (distribution of cells in G0/G1, S, G2/M phases). All four dental resin polymerization initiators induced G0/G1 cell cycle arrest. As for the patterns of cell death (necrosis and/or apoptosis), they were analyzed using Annexin V-FITC/PI staining with flow cytometry. All four dental resin polymerization initiators most likely induced necrosis.

Immobilization of simulated reducing agent at the surface of SiO2 fillers in dental composite resins.

To reduce the leachability of reducing agents from composite resins, immobilization of a simulated reducing agent at the surface of SiO2 fillers was examined. SiO2 plates were immersed in 2% 3-aminopropyltriethoxy silane/ethanol solution, and then immersed in dimethyl sulfoxide with 0.25 wt% 4-dimethyl amino benzoic acid (DMABA), 2.0 wt% 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, and 0.5 wt% N-hydroxysuccinimide. Wide-scan spectrum of X-ray photoelectron spectroscopy did not detect carbon contamination. However, narrow scan detected an O=C-N peak at 399.8 eV, suggesting that DMABA could be immobilized on silane-coupled SiO2 plates. Further, surface plasmon resonance analysis indicated the adsorption of MMA at the surface of reducing agent-immobilized plate.

Synthetic osteopontin-derived peptide SVVYGLR can induce neovascularization in artificial bone marrow scaffold biomaterials.

We have previously reported that an osteopontin-derived SVVYGLR peptide exhibited potent angiogenic activity in vitro and in vivo. In the present study, the focus points were on the in vitro effect of SVVYGLR on bone marrow stromal cell proliferation, as well as its in vivo effect on bone tissue formation when grafts made of CO3Ap-collagen sponge- as a scaffold biomaterial containing the SVVYGLR motif - were implanted. SVVYGLR peptide promoted bone marrow stromal cell proliferation. When a CO3Ap-collagen sponge containing SVVYGLR peptide was implanted as a graft into a tissue defect created in rat tibia, the migration of numerous vascular endothelial cells - as well as prominent angiogenesis - inside the graft could be detected after one week. These results thus suggested that our scaffold biomaterials including the peptide could be useful for bone tissue regeneration.