Radiographic study of the distal ulna in rheumatoid arthritis with extensor digitorum communis ruptures.

OBJECTIVES: Extensor digitorum communis rupture of the wrist often occurs in patients with rheumatoid arthritis. Early operation is desirable for patients with a high risk of rupture; therefore, rheumatologists should diagnose it during daily examinations. This study aimed to clarify radiographic changes in the distal ulna and related factors associated with extensor digitorum communis rupture in patients with rheumatoid arthritis. METHODS: We analysed plain radiographs of 40 patients with rheumatoid arthritis associated with extensor digitorum communis rupture and 62 healthy controls. We investigated the deformation of the distal ulna, Larsen grades, and radiological parameters such as ulnar variance, ulnar bowing angle, dorsal protrusion, and dorsal bowing angle. RESULTS: The ratios of the ulna head deformation, Larsen grades, ulnar variance, dorsal protrusion, and dorsal bowing angle were significantly larger in the ruptured group than in the control group. Multiple logistic regression analysis revealed that dorsal protrusion and Larsen grades were significantly associated with extensor digitorum communis rupture. CONCLUSIONS: Deformity of the distal ulna is evident in patients with an extensor digitorum communis rupture. Ulnar head deformation, high Larsen grades, and large dorsal protrusion are potential risk factors for extensor digitorum communis rupture.

Methamphetamine induces endoplasmic reticulum stress related gene CHOP/Gadd153/ddit3 in dopaminergic cells.

We examined the toxicity of methamphetamine and dopamine in CATH.a cells, which were derived from mouse dopamine-producing neural cells in the central nervous system. Use of the quantitative real-time polymerase chain reaction revealed that transcripts of the endoplasmic reticulum stress related gene (CHOP/Gadd153/ddit3) were considerably induced at 24-48 h after methamphetamine administration (but only under apoptotic conditions), whereas dopamine slightly induced CHOP/Gadd153/ddit3 transcripts at an early stage. We also found that dopamine and methamphetamine weakly induced transcripts for the glucose-regulated protein 78 gene (Grp78/Bip) at the early stage. Analysis by immunofluorescence microscopy demonstrated an increase of　CHOP/Gadd153/ddit3 and Grp78/Bip proteins at 24 h after methamphetamine administration. Treatment of CATH.a cells with methamphetamine caused a re-distribution of dopamine inside the cells, which mimicked the presynaptic activity of neurons with cell bodies located in the ventral tegmental area or the substantia nigra. Thus, we have demonstrated the existence of endoplasmic reticulum stress in a model of presynaptic dopaminergic neurons for the first time. Together with the recent evidence suggesting the importance of presynaptic toxicity, our findings provide new insights into the mechanisms of dopamine toxicity, which might represent one of the most important mechanisms of methamphetamine toxicity and addiction.