Risk of major bleeding at different PT-INR ranges in elderly Japanese patients with non-valvular atrial fibrillation receiving warfarin: a nested case-control study.

BACKGROUND: Debate continues about the optimal anticoagulation level for elderly Japanese patients with non-valvular atrial fibrillation (NVAF) receiving warfarin. The Japanese Circulation Society guideline has recommended prothrombin time-international normalized ratios (PT-INR) of 1.6 - 2.6 for elderly patients and 2.0 - 3.0 for non-elderly patients, because previous observational studies indicated increased risk of bleeding when the ratio exceeded 2.6. We aimed to reappraise the relationship between PT-INR and the risk of major bleeding in elderly Japanese patients. METHODS: From the electronic medical records, we selected a cohort of elderly (age ≥ 70 years) Japanese patients with NVAF who were prescribed warfarin for the prevention of thromboembolic diseases between November 2010 and March 2014 at Kanto Rosai Hospital. We identified those who developed major bleeding (cases). For each case, we randomly selected two matched controls by adopting a risk-set sampling method defined by calendar date, age, gender, length of warfarin administration, and the prescriber of warfarin. The risk of major bleeding in patients having PT-INR ≤ 1.49, 1.50 - 1.99, 2.00 - 2.49 (the reference), 2.50 - 2.99, and ≥ 3.00 were compared using the conditional logistic regression method. The study protocol was approved by the IRB before the study was begun. RESULTS: Among the cohort of 806 elderly patients, we identified 32 cases and selected 64 matched controls. The overall incidence of major bleeding was 3.5 per 100 patient-years. The odds ratios (95 % confidence intervals) for the risk of developing major bleeding in patients with PT-INR ≤ 1.49 (n = 20), 1.50 - 1.99 (n = 32), 2.00 - 2.49 (n = 18), 2.50 - 2.99 (n = 10), and ≥ 3.00 (n = 16) were 1.0 (0.2, 5.9), 0.3 (0.1, 1.9), 1.0 (reference), 1.2 (0.2, 8.4), and 19.8 (2.0, 198.9), respectively, with a significant difference between ≥ 3.00 and reference. CONCLUSIONS: Among elderly Japanese patients with NVAF, PT-INR 2.0 - 3.0 may be associated with a clinically permissible risk of major bleeding while PT-INR ≥ 3.00 a significant risk. Further studies are warranted to determine whether the risk of major bleeding is significantly lower for PT-INR 2.50 - 2.99 than for PT-INR ≥ 3.00.

Versatile supramolecular cross-linker: a rotaxane cross-linker that directly endows vinyl polymers with movable cross-links.

A supramolecular cross-linked cross-linker, capable of introducing rotaxane cross-links to vinyl polymers, has been developed for the rational synthesis of polyrotaxane networks. The experimental results reveal that the combination of an oligocyclodextrin (OCD) and a terminal bulky group-tethering macromonomer (TBM) forms a polymer-network structure having polymerizable moieties through supramolecular cross-linking. Radical polymerization of a variety of typical vinyl monomers in the presence of the vinylic supramolecular cross-linker (VSC) afforded the corresponding vinyl polymers cross-linked through the rotaxane cross-links (RCP) as transparent stable films in high yields under both photoinitiated and thermal polymerization conditions. A poly(N,N-dimethylacrylamide)-based hydrogel synthesized by using VSC, RCPDMAAm , displayed a unique mechanical property. The small-angle X-ray scattering (SAXS) results, indicating patterns characteristic of a polyrotaxane network, clearly suggested the presence and role of the rotaxane cross-links. The confirmation of the introduction of rotaxane-cross-links into vinyl polymers strongly reveals the significant usefulness of VSC.

Guest-induced crystal-to-crystal transitions of poly(L-lactide) complexes.

In this study, we systematically investigated various crystal-to-crystal transitions relating to poly(L-lactide) (PLLA) cocrystallized with low-molecular-weight compounds using wide-angle X-ray diffraction and Fourier transform infrared spectroscopy. First, the solvent exchange and the resultant crystal transition of solvent complexes were investigated. Basically, the solvent exchange treatments at -25 °C became successful, although some specific phenomena depending on solvent species were seen. The ratio of the α-form in the crystalline region increased by an increase in the solvent exchange temperature. Second, the crystal transition behavior between CO(2) and solvent complexes was investigated. The complete transition from solvent complex to CO(2) complex was observed for all solvent complexes. In contrast, it was found that types of solvents and the surrounding temperature have a great effect on the transition behavior from CO(2) to solvent complexes. Finally, the guest-induced transitions of noncomplex crystals (α-, α'-, and α″-forms) were examined. As a result, it was revealed that the guest-induced transition behavior of noncomplex crystals was much influenced by the order of crystal (chain conformation and packing) of noncomplexes (α, α', and α″) as well as kinds of guests.

Removal of fluoride ions from aqueous solution at low pH using schwertmannite.

Wastewater containing fluoride requires polishing after precipitation/coagulation treatment in order to meet stringent environmental legislation. Accordingly, adsorption characteristics of fluoride onto schwertmannite adsorbent were studied in a batch system with respect to changes in initial concentration of fluoride, equilibrium pH of sample solution, adsorbent dosage and co-existing ions. Equilibrium adsorption data were obtained at 295.6, 303 and 313 K, and are interpreted in terms of two-site Langmuir, Freundlich, Langmuir-Freundlich, Redlich-Peterson, Tóth and Dubinin-Radushkevitch isotherm models. The experimental and equilibrium modeling results revealed that the capacity of schwertmannite for fluoride is high but insensitive to changes in solution temperature. An increase in equilibrium pH of sample solution reduced significantly the fluoride removal efficiency. In binary component systems, inner-sphere complex forming species had negative effects on fluoride adsorption while outer-sphere complex forming species improved slightly the fluoride removal efficiency. The schwertmannite adsorbent was regenerable and had the ability to lower the fluoride concentration to acceptable levels.

Applied magnetic field rejects the coating of ferromagnetic carbon from the surface of ferromagnetic cobalt: RAPET of CoZr2(acac)2(OiPr)8.

We present the results of the RAPET (reaction under autogenic pressure at elevated temperatures) dissociation of CoZr(2)(acac)(2)(O(i)Pr)(8) at 700 degrees C in a closed Swagelok cell under an applied magnetic field of 10 T. It produces a mixture of carbon-coated and noncoated metastable ZrO(2) nanoparticles, bare metallic Co nanoparticles, and bare carbon. The same reaction in the absence of a magnetic field produces spherical Co and ZrO(2) particles in sizes ranging from 11 to 16 nm and exhibiting, at room temperature, metastable phases: fcc for cobalt and a tetragonal phase for zirconia. The metastable phases of Co and ZrO(2) are manifested because of a carbon shell of approximately 4 nm thickness anchored to their surfaces. The effect of an applied magnetic field to synthesize morphologically different, but structurally the same, products is the key topic of the present paper.