High-density volumetric super-resolution microscopy

Volumetric super-resolution microscopy typically encodes the 3D position of single-molecule fluorescence into a 2D image by changing the shape of the point spread function (PSF) as a function of depth. However, the resulting large and complex PSF spatial footprints reduce biological throughput and applicability by requiring lower labeling densities to avoid overlapping fluorescent signals. We quantitatively compare the density dependence of single-molecule light field microscopy (SMLFM) to other 3D PSFs (astigmatism, double helix and tetrapod) showing that SMLFM enables an order-of-magnitude speed improvement compared to the double helix PSF by resolving overlapping emitters through parallax. We demonstrate this optical robustness experimentally with high accuracy ( > 99.2 ± 0.1%, 0.1 locs μm-2) and sensitivity ( > 86.6 ± 0.9%, 0.1 locs μm-2) through whole-cell (scan-free) imaging and tracking of single membrane proteins in live primary B cells. We also exemplify high-density volumetric imaging (0.15 locs μm-2) in dense cytosolic tubulin datasets.

Results of 115 Rubis II reverse thumb carpometacarpal joint prostheses with a mean follow-up of 10 years

The aim of this study was to assess the clinical and radiological results of the Rubis II thumb carpometacarpal joint reverse prosthesis, at a mean follow-up of 10 years. Between 1997 and 2008, 253 prostheses were implanted in 199 patients; 115 were reviewed. The survival after a mean of 10 years was 89%. At the last follow-up, 70% of prostheses were painless; the others reported moderate or intermittent pain. The satisfaction rate was 98%. The mean opposition was 9 on the Kapandji scale; the mean QuickDASH score was 30. Wrist, key and tip pinch strengths were comparable with the non-operated side. Of the 115 implants, one was radiologically loose (1%) and 15 had suffered dislocations (13%), 12 of which were caused by an injury. Eleven thumbs had revision surgery. This study confirms that the good clinical results of the Rubis II prosthesis are maintained in the medium and long term, and represents a useful alternative to trapeziectomy for selected patients.

LEVEL OF EVIDENCE

IV.

[Treatment of fresh humeral diaphysis fractures by Seidel intramedullary locked nailing. A study of 23 initial cases after 2.5 years with rotator cuff evaluation]

PURPOSE OF THE STUDY

The Seidel intramedullary locking nail is one of the alternative methods for operative treatment of humeral shaft fractures. Short follow-up demonstrated persistent pain and stiffness at the shoulder joint. The aims of this retrospective study were first to evaluate results with attention to operative technique, consolidation rate and postoperative complications. Second we studied rotator cuff healing in our first patients.

MATERIAL AND METHODS

Twenty-five acute diaphyseal fractures were treated between May 91 and Dec 94. We reviewed personally 23 patients with a mean follow-up of 33 months (range 22-66). The dominant fracture type according to AO was type A. Clinical shoulder assessment was carried out using the Constant score. Isometric strength was recorded in both shoulders with a hand-held dynamometer in abduction, external and internal rotation. Sonographic evaluation of the rotator cuff was performed using a 7.5 MHz linear array transducer in all 23 patients.

RESULTS

All but one fracture healed at an average of two months. Impingement was observed in three patients but pain relief and normal shoulder motion have been reached after nail removal. Infection occurred in one patient but final result was good. Constant score averaged 78.7 (range 51-94.2) classifying the result in all but two patients as excellent or good. Compared with the external and internal rotations, strength was significantly reduced in abduction but reached 83.5 per cent of the opposite shoulder. No statistical differences were found in relation with age, gender and side. Compared with the contralateral shoulder, rotator cuff evaluation with sonography was considered as normal in 18 patients. Calcium deposits of the cuff were noticed in the infected patient. In three cases sonography detected hyperechoic line considered as scar in the supraspinatus tendon without any partial or full-thickness tear.

DISCUSSION AND CONCLUSION

A median starting point avoids the avascular area and gives a straight access to the medullary canal. This study demonstrates that using this entry portal and a reliable technique antegrade nailing of the humerus does not compromise rotator cuff healing and shoulder function. Technical errors lead to poor or fair results but despite this learning curve, Seidel nail when operative treatment is indicated, is a good choice. Attention must be paid to patients with clinical history of impingement or rotator cuff tendinopathy.