Isolation and characterization of a tetranuclear Pt-FeFe-Pt intermediate en route to the trinuclear Pt-Fe-Pt cluster.

An intermediate compound, [{PtFe(piam)2(NH3)2(OCH3)}2(µ-OCH3)2](ClO4)2 (1, piam = pivalamidate), in the synthetic process to form [Pt2Fe(piam)4(NH3)4](ClO4)3 (2) by mixing cis-[Pt(piam)2(NH3)2]·2H2O and iron sources was successfully isolated and characterized by single-crystal X-ray analysis. In 1, the platinum and iron atoms are bridged by two piam ligands to afford a dinuclear Pt-Fe structure and are further linked to each other by methoxide bridges at the equatorial positions of iron atoms to form a tetranuclear Pt-FeFe-Pt complex. The Pt-Fe distances in 1 are 3.0010(16) and 2.9883(17) Å, which are significantly longer than those in 2 (2.5566(15) and 2.5718(15) Å). X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and magnetic susceptibility measurements revealed that the oxidation states are Pt(+2)-Fe(+3)Fe(+3)-Pt(+2) (1) and Pt(+2)-Fe(+3)-Pt(+2) (2) with high-spin (S = 5/2) configurations in iron atoms. The magnetic susceptibility of 1 has a χT value of 5.83 cm3 mol-1 K per Pt(+2)-Fe(+3)Fe(+3)-Pt(+2) unit at 300 K, which decreases down to 0.04 cm3 mol-1 K at 7 K due to antiferromagnetic coupling (J = -28 cm-1) of the two Fe(+3) centers. Compound 2 maintains its trinuclear structure in MeCN, exhibiting reversible one-electron reduction and oxidation, Pt(+2)-Fe(+2)-Pt(+2) ↔ Pt(+2)-Fe(+3)-Pt(+2), at E1/2 = -0.19 V (vs. Fc/Fc+). However, in MeOH, compound 2 is decomposed into a dinuclear structure of Pt-Fe involving an equilibrium between 1 and 2.

Clinical Effectiveness of Intermittent Infusion Hemodiafiltration Using Backfiltration of Ultrapure Dialysis Fluid Compared with Predilution On-Line Hemodiafiltration.

BACKGROUND: In conventional hemodialysis (HD) treatment, excessive water removal sometimes induces a rapid drop in blood pressure. Intermittent infusion hemodiafiltration (I-HDF) has been developed to improve patients' peripheral circulation by repeated intermittent infusion during HD treatment. SUMMARY: A prospective, multicenter, parallel group comparative trial examined the clinical effectiveness of I-HDF compared with predilution on-line HDF (pre-HDF), the most popular on-line HDF therapy in Japan. Patients were allocated to 2 groups after matching for age (± 5 years), dry weight (± 5 kg), and presence/absence of diabetes. After informed consent was obtained, 36 patients (18 pairs) participated in the trial. The results showed no difference in clinical condition or quality of life (QOL) scores between the 2 therapy groups. The rate of reduction in systolic blood pressure initially showed no difference between the groups, but decreased slightly as the trial proceeded after changing from HD therapy. There was also no difference in the incidence rate of treatments initially, although this significantly decreased in both groups as the trial proceeded. Rates of ß2-microglobulin removal were significantly higher in the pre-HDF group than in the I-HDF group. At the same time, the amount of albumin leakage during treatment was significantly greater in the pre-HDF group. Key Messages: The clinical condition and QOL of patients receiving I-HDF was not inferior to those receiving pre-HDF. Pre-HDF demonstrated a significantly higher removal rate of middle- and larger-molecular-weight solutes and higher albumin leakage compared with I-HDF.

Validating the absolute reliability of a fat free mass estimate equation in hemodialysis patients using near-infrared spectroscopy.

The assessment of nutritional states using fat free mass (FFM) measured with near-infrared spectroscopy (NIRS) is clinically useful. This measurement should incorporate the patient's post-dialysis weight ("dry weight"), in order to exclude the effects of any change in water mass. We therefore used NIRS to investigate the regression, independent variables, and absolute reliability of FFM in dry weight. The study included 47 outpatients from the hemodialysis unit. Body weight was measured before dialysis, and FFM was measured using NIRS before and after dialysis treatment. Multiple regression analysis was used to estimate the FFM in dry weight as the dependent variable. The measured FFM before dialysis treatment (Mw-FFM), and the difference between measured and dry weight (Mw-Dw) were independent variables. We performed Bland-Altman analysis to detect errors between the statistically estimated FFM and the measured FFM after dialysis treatment. The multiple regression equation to estimate the FFM in dry weight was: Dw-FFM = 0.038 + (0.984 × Mw-FFM) + (-0.571 × [Mw-Dw]); R(2) = 0.99). There was no systematic bias between the estimated and the measured values of FFM in dry weight. Using NIRS, FFM in dry weight can be calculated by an equation including FFM in measured weight and the difference between the measured weight and the dry weight.

Investigation of factors affecting the six-minute walk test results in hemodialysis patients.

Renal anemia, uremic myopathy, and malnutrition are some of the factors that affect the results of the 6-minute walk test (6MWT) in hemodialysis patients. We hypothesized that skeletal muscle dysfunction caused by skeletal myolysis, protein hypercatabolism, and mitochondrial deficiency are strongly related factors. The purpose of this study was to clarify the factors that affect the 6MWT results in hemodialysis patients to assess their exercise tolerance. The study included 43 outpatients from the hemodialysis unit. The 6MWT was performed, and knee extension strength, 1-leg standing time, and grip were measured. In addition, the subjects' characteristics such as age, preexisting coronary artery disease, hemoglobin level, total iron binding capacity, serum albumin level, creatinine generation rate, and normalized protein catabolic rate were investigated. A stepwise multiple regression model was used to examine the factors affecting the 6MWT results. Multiple regression analysis revealed that knee extension strength (ß=0.446, P=0.001), total iron binding capacity (ß=-0.299, P=0.021), and preexisting coronary artery disease (ß=-0.272, P=0.035) significantly affected the 6MWT results (R=0.66, R(2)=0.44). The 6MWT in hemodialysis patients was strongly affected by muscle strength, iron deficiency anemia, and preexisting coronary artery disease, suggesting that resistance training is important for improving 6MWT results. Our findings indicate that iron deficiency and cardiac function should be assessed before exercising or undergoing an exercise tolerance test.

Improvement of autonomic nervous regulation by blood purification therapy using acetate-free dialysis fluid - clinical evaluation by laser Doppler flowmetry.

In Japan, acetate-free biofiltration (AFBF) became commercially available in the year 2000, and these products have been reported to be clinically effective for controlling the decrease of blood pressure during dialysis or various types of dialysis intolerance. And more, acetate-free dialysis fluid was made clinically available in 2007, acetate-free hemodialysis (AFHD) is expected to inhibit the malnutrition-inflammation-atherosclerosis syndrome, improve anemia and the nutritional status of patients, stabilize hemodynamics, and reduce inflammation and oxidative stress. In a broad sense, AFBF can be classified as hemodiafiltration (HDF), and its clinical effects seem to be associated with multiple factors, including use of acetate-free dialysis fluid, massive removal of low molecular weight proteins by convection, and the sodium concentration of the replacement fluid. Therefore, the clinical significance of acetate-free dialysis fluid could be demonstrated more clearly by comparing AFHD with conventional hemodialysis (conv. HD) using dialysis fluid containing about 10 mEq/l acetate. Since 2005, we have been investigating the efficacy of various modalities of blood purification therapy by continuously monitoring changes of tissue blood flow in the lower limbs and earlobes (head) using non-invasive continuous monitoring method (NICOMM). In this report, we assess the clinical effectiveness of AFHD on the basis of clinical findings and head stability index (head SI) obtained by NICOMM, particularly with respect to the influence on autonomic regulation. After switching to AFHD from conv. HD, anemia, stored iron utilization, and the frequency of treatments for dialysis hypotension and of muscle cramps were significantly improved. Further, the head SI was also significantly smaller with AFHD than conv. HD. This finding suggests that AFHD improved the maintenance of homeostasis by the autonomic nervous regulation system. In addition, we could not find clinical features of excessive alkalosis during an observation period of about 1 year, even if online HDF using acetate-free dialysis fluid as the substitution fluid. Our conclusion is that the advent of acetate-free dialysis fluid has led to investigations into new clinical effectiveness of AFHD or online HDF/HF using ultrapurified acetate-free dialysis fluid as the substitution fluid.

Fully automated dialysis system based on the central dialysis fluid delivery system.

The fully automated dialysis system (FADS) was developed as an improvement over previous patient monitors used in the treatment of hemodialysis, with the aim of standardizing and promoting labor-saving in such treatment. This system uses backfiltration dialysis fluid to perform priming, blood rinse back and rapid fluid replenishment, and causes guiding of blood into the dialyzer by the drainage pump for ultrafiltration. This requires that the dialysis fluid used be purified to a high level. The central dialysis fluid delivery system (CDDS) combines the process of the creation and supply of dialysis water and dialysis fluid to achieve a level of purity equivalent with ultrapure dialysis fluid. FADS has the further advantages of greater efficiency and streamlined operation, reducing human error and the risk of infection without requiring the storage or disposal of normal saline solution. The simplification of hemodialysis allows for greater frequency of dialysis or extended dialysis, enabling treatment to be provided in line with the patient's particular situation. FADS thus markedly improves the reliability, safety and standardization of dialysis procedures while ensuring labor-saving in these procedures, making it of particular utility for institutions dealing with dialysis on a large scale.