It is believed that variations in k32 account for the variation in the overall complexation constants KT. The relative constancy in kS2 for 15-crown-5 is consistent with the observed nonselectivity of the ligand in complexing with the univalent ions.Without exception, ki2 has increased in going from 18-crown-6 to 15-crown-5; that is, decomplexation is facilitated by the smaller ring size and increased rigidity. This, too, is consistent with the observation that is greater for the 18-crown-6 complexes. kS2 increases monotonically with cation radius for the alkali metal ions with an increase over the values for 18-crown-6 by a factor of 10-20 for the largest ions. For Ag+ and Tl+, the simple relation between rate and ion size is lost, indicative again of the increasingly important steric or geometric factors in relation to a simple size factor.

We describe a 79-year-old woman with rheumatoid arthritis who suffered from subchondral insufficiency fracture of the femoral head (SIF) and contralateral femoral neck fracture. Radiographs obtained two months after the onset of thigh pain showed collapse of the right femoral head and contralateral femoral neck fracture. MRI revealed a subchondral serpiginous low-intensity band in the right femoral head on the T2-weighted image. This case report suggests that SIF should be considered in the differential diagnoses of rheumatic patients who suffer from thigh pain without antecedent trauma.

These findings support the critical role of concomitant MTX in the efficacy of ADA, and recommend use of MTX ≥10 mg in Japanese RA patients.

These results suggest that the highly cross-linked polyethylene reduces penetration of the femoral head and may be an optimal bearing surface for patients receiving total hip arthroplasty.

In patients with RA, TCZ is highly effective for both biologics-naïve patients and patients previously exposed to biologics, achieving a high remission rate and drug continuation rate (68.2 %) in clinical practice.