A study of clinical anatomy of the safe zone for the volar approach for wrist arthroscopy.

OBJECTIVE: The current study was to perform an anatomical observation of the volar approach for wrist arthroscopy and to establish the safe zone for this approach. METHODS: Eight preserved specimens and 2 fresh specimens were used to simulate the medial-to-lateral operation and to mark the volar approach. Based on anatomical measurements of the volar approach, the closest distances from the 1/2, 6R, 6U, VR, VR' and VU approaches to the adjacent important structures were established. RESULTS: The closest distance from the 1/2 approach to the superficial branch of the radial nerve was 2.4±1.5mm. The closest distances from the 6U and 6R approaches to the dorsal carpal branch of the ulnar nerve were 16.2±1.3mm and 9.0±2.4mm, respectively. The closest distances from the VR and VR' approaches to the palmar cutaneous branch of the median nerve were 6.7±1.1mm and 2.8±0.9mm, respectively; the closest distances to the radial artery were 6.3±4.0mm and 10.0±3.4mm, respectively. Moreover, both of the two approaches passed through the base of the flexor carpi radialis tendon. The closest distance from the VU approach to the ulnar artery and flexor digitorum profundus tendon were 3.3±1.4mm and 0.3±2.5mm, respectively. CONCLUSIONS: In conclusion, a safe zone could be located for the establishment of the volar approach for wrist arthroscopy. LEVEL OF EVIDENCE: III; retrospective study with no control group.

LPS1, Encoding Iron-Sulfur Subunit SDH2-1 of Succinate Dehydrogenase, Affects Leaf Senescence and Grain Yield in Rice.

The iron-sulfur subunit (SDH2) of succinate dehydrogenase plays a key role in electron transport in plant mitochondria. However, it is yet unknown whether SDH2 genes are involved in leaf senescence and yield formation. In this study, we isolated a late premature senescence mutant, lps1, in rice (Oryza sativa). The mutant leaves exhibited brown spots at late tillering stage and wilted at the late grain-filling stage and mature stage. In its premature senescence leaves, photosynthetic pigment contents and net photosynthetic rate were reduced; chloroplasts and mitochondria were degraded. Meanwhile, lps1 displayed small panicles, low seed-setting rate and dramatically reduced grain yield. Gene cloning and complementation analysis suggested that the causal gene for the mutant phenotype was OsSDH2-1 (LOC_Os08g02640), in which single nucleotide mutation resulted in an amino acid substitution in the encoded protein. OsSDH2-1 gene was expressed in all organs tested, with higher expression in leaves, root tips, ovary and anthers. OsSDH2-1 protein was targeted to mitochondria. Furthermore, reactive oxygen species (ROS), mainly H2O2, was excessively accumulated in leaves and young panicles of lps1, which could cause premature leaf senescence and affect panicle development and pollen function. Taken together, OsSDH2-1 plays a crucial role in leaf senescence and yield formation in rice.