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.

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.

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.

Comparison of hexagonal crystal structures between fluorapatite and polytetrafluoroethylene.

The crystallographic properties of fluorapatite (FAp) and polytetrafluoroethylene (PTFE) as biomedical materials were compared. Both materials contain fluorine and casually belong to the hexagonal crystal system. It is interesting that FAp is an inorganic ionic crystal, while PTFE is an organic covalent-bond crystal. Generally, fluorine contributes to the physicochemical stability and in some cases to the biocompatibility. The crystal structure of FAp was initially analyzed in 1930 by Náray-Szabó, although the analysis of hydroxyapatite (HAp) was markedly delayed until 1964. The computer graphics display demonstrated that fluoride ions serve to stabilize the hydroxyapatite crystals and prevent dental caries. On the other hand, PTFE crystal analysis was reported in 1954 by Bunn and Howells. The PTFE temperature-pressure phase diagram accepted for over 60 years is very complicated and insufficient. PTFE delicately changes its phase near room temperature, although at a glance it appears to have a simple form compared with DNA.

Effect of Taurine on Hemodiafiltration in Patients With Chronic Heart Failure.

Taurine, an important factor in the living body, is essential for cardiovascular function and development and function of skeletal muscle, retina and central nervous system. In the present study, its effect on cardiovascular function was specifically taken into consideration. In hemodiafiltration (HDF) patients, the effect of taurine on patients with chronic heart failure (CHF), in whom dry weight was difficult to control, was evaluated. All patients who were subjected to regular HDF for 4 h three times per week at Joban hospital were included in this study. Patients with chronic heart failure, in whom dry weight was difficult to control (N = 4), were included in the evaluation of clinical status. X-ray and echocardiography were determined before and after taurine treatment. Almost all patients were taking nitric acid, warfarin, anti-platelet agents and vasopressors. Because vital signs were unstable in chronic heart failure, all cases withheld antihypertensive drugs during HDF. For unstable vital signs during HDF, pulmonary congestion was chronically recognized. After taurine was started, vital signs stabilized and lowering of dry weight was possible. In addition, X-ray and cardiac diastolic failure on echocardiography improved. Taurine was effective for CHF patients on HDF in whom dry weight was difficult to control in spite of various medications.

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.

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.

The synthesis and characterization of a novel potassium chloride-fluoridated hydroxyapatite varnish for treating dentin hypersensitivity.

Dentin hypersensitivity is treated using materials that occlude the dentinal tubules or release potassium ions that induce nerve desensitization. In this study we formulated a novel varnish containing potassium chloride and fluoridated hydroxyapatite and evaluated its physical properties and cytotoxicity. Potassium ion release from the varnish was measured. Dentin permeability was evaluated by measuring the hydraulic conductance of etched dentin discs treated with the varnish. The direct contact test and MTT assay were performed to evaluate the varnish's cytotoxicity. We found that the varnish released potassium ions over 6 h, and demonstrated a statistically higher reduction in dentin permeability compared to commercial fluoride varnish or control. Dentin disc scanning electron microscopy images demonstrated occluded dentinal tubules in the novel varnish group after brushing. The cytotoxicity tests indicated the varnish was biocompatible with gingival and pulpal fibroblasts. We propose the novel varnish is a potential material for use in hypersensitivity management.

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.

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.

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.

Influence of alkyl chain length on calcium phosphate deposition onto titanium surfaces modified with alkylphosphonic acid monolayers.

Much attention has been paid to the modification of a titanium surface with an alkylphosphonic acid (PA)-based self-assembled monolayer (SAM) to accelerate hydroxyapatite (HA) deposition on the surface. In order to further accelerate the rate of HA deposition, we examined here the effect of alkyl chain length of SAMs on the formation of a HA layer. PAs with three different alkyl chain lengths (3, 6, and 16 methylene units) were used for the preparation of a SAM on titanium. The titanium specimens with monolayers were soaked in a simulated body fluid under physiological conditions for 4 weeks. The deposited substances were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. These analyses revealed that the formation of PA SAMs accelerate the deposition of poorly crystallized HA, in an alkyl chain length-dependent manner. Among PAs studied here, PA containing a 16-carbon alkyl chain gave rise to the titanium surface most effective for the deposition of HA.

Influence of air-abrasion and subsequent heat treatment on bonding between zirconia framework material and indirect composites.

The purpose of this study was to evaluate the influence of air-abrasion and subsequent heat treatment on the shear bond strength of the bond between indirect composites and a zirconia material. Four surface preparations were employed; ground flat, then heated to regenerate the crystal phase (C); air-abraded with alumina for 10 s (S10), for 20 s (S20), and air-abraded for 10 s and heated (H). Disks were primed with Alloy Primer and bonded either with Estenia or with Gradia composite. XRD analysis suggested that the monoclinic zirconia content was increased by air-abrasion, and decreased by heating. The surface roughness of S10, S20 and H disks was similar. Nevertheless, H groups showed lower bond strengths than the S10 and S20 groups both before and after thermal cycling. Although alumina air-abrasion considerably enhanced bonding between zirconia and indirect composites, subsequent heat treatment had a negative effect on the durability of bond strength.

A novel glass ionomer cement containing MgCO(3 )apatite induced the increased proliferation and differentiation of human pulp cells in vitro.

This study aimed to investigate the in vitro biological response of human dental pulp cells to glass ionomer cement (GIC, Fuji IX GP(®)) containing 2.5% magnesium carbonate apatite (MgCO(3)Ap). MgCO(3)Ap was synthesized by wet method and characterized using FT-IR, XPS, and SEM. Fuji IX GP(®) served as a control. Test and control cements were prepared by encapsulated mixing the powder with Fuji IX-liquid (P/L=3.6:1). Eluates from cements extracted by 1 mL culture medium were collected at day 1, 7 and 14, and used for WST-1 proliferation assay. For ALPase activity, cells were maintained with cements in transwells, harvested and enzyme activity was measured at day 1, 4, 7, 14, and 21. We found a higher cell proliferation and increased ALPase activity by pulp cells in the test group compared to the control. This suggests the potential of GIC containing this novel biological apatite as a restorative material for pulp-dentin regeneration.

Real time assessment of surface interactions with a titanium passivation layer by surface plasmon resonance.

Due to the high corrosion resistance and strength to density ratio titanium is widely used in industry, and also in a gamut of medical applications. Here we report for the first time on our development of a titanium passivation layer sensor that makes use of surface plasmon resonance (SPR). The deposited titanium metal layer on the sensor was passivated in air, similarly to titanium medical devices. Our "Ti-SPR sensor" enables analysis of biomolecule interactions with the passivated surface of titanium in real time. As a proof of concept, corrosion of a titanium passivation layer exposed to acid was monitored in real time. The Ti-SPR sensor can also accurately measure the time-dependence of protein adsorption onto the titanium passivation layer at sub-nanogram per square millimeter accuracy. Besides such SPR analyses, SPR imaging (SPRI) enables real time assessment of chemical surface processes that occur simultaneously at "multiple independent spots" on the Ti-SPR sensor, such as acid corrosion or adhesion of cells. Our Ti-SPR sensor will therefore be very useful to study titanium corrosion phenomena and biomolecular titanium-surface interactions with application in a broad range of industrial and biomedical fields.

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.