The usefulness of c-Kit in the immunohistochemical assessment of melanocytic lesions

C-Kit (CD117), the receptor for the stem cell factor, a growth factor for melanocyte migra- tion and proliferation, has shown differential immunostaining in various benign and malig- nant melanocytic lesions. The purpose of this study is to compare c-Kit immunostaining in benign nevi and in primary and metastatic malignant melanomas, to determine whether c-Kit can aid in the differential diagnosis of these lesions. c-Kit immunostaining was per- formed in 60 cases of pigmented lesions, including 39 benign nevi (5 blue nevi, 5 intra- dermal nevi, 3 junctional nevi, 15 cases of pri- mary compound nevus, 11 cases of Spitz nevus), 18 cases of primary malignant melanoma and 3 cases of metastatic melanoma. The vast majority of nevi and melanomas examined in this study were posi- tive for c-Kit, with minimal differences between benign and malignant lesions. C-Kit cytoplasmatic immunoreactivity in the intraepidermal proliferating nevus cells, was detected in benign pigmented lesions as well as in malignant melanoma, increasing with the age of patients (P=0.007) in both groups. The patient’s age at presentation appeared to be the variable able to cluster benign and malignant pigmented lesions. The percentage of c-Kit positive intraepidermal nevus cells was better associated with age despite other vari- ables (P=0.014). The intensity and percentage of c-Kit positivity in the proliferating nevus cells in the dermis was significantly increased in malignant melanocytic lesions (P=0.015 and P=0.008) compared to benign lesions (compound melanocytic nevi, Spitz nevi, intradermal nevi, blue nevi). Immunostaning for c-Kit in metastatic melanomas was nega- tive. Interestingly in two cases of melanoma occurring on a pre-existent nevus, the melanoma tumor cells showed strong cytoplas- matic and membranous positivity for c-kit, in contrast with the absence of any immunoreac- tivity in pre-existent intradermal nevus cells. C-Kit does not appear to be a strong immuno- histochemical marker for distinguishing melanoma from melanocytic nevi, if we consid- er c-Kit expression in intraepidermal prolifer- ating cells. The c-Kit expression in proliferat- ing melanocytes in the dermis could help in the differential diagnosis between a superfi- cial spreading melanoma (with dermis inva- sion) and a compound nevus or an intradermal nevus. Finally, c-Kit could be a good diagnostic tool for distinguishing benign compound nevi from malignant melanocytic lesions with der- mis invasion and to differentiate metastatic melanoma from primary melanoma

Promoting Reuse with Active Reuse Repository Systems

Abstract. Software component-based reuse is diÆcult for software de-velopers to adopt because rst they must know what components exist in a reuse repository and then they must know how to retrieve them easily. This paper describes the concept and implementation of active reuse repository systems that address the above two issues. Active reuse repository systems employ active information delivery mechanisms to deliver potentially reusable components that are relevant to the current development task. They can help software developers reuse components they did not even know existed. They can also greatly reduce the cost of component location because software developers need neither to specify reuse queries explicitly, nor to switch working contexts back and forth between development environments and reuse repository systems.

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Arthroscopic Primary Repair of Proximal Anterior Cruciate Ligament Tears

In a select group of patients with proximal anterior cruciate ligament (ACL) tears, primary repair can be a useful technique. Preservation of the native ACL may be advantageous for proprioceptive function and is thought to restore normal knee joint kinematics. The procedure is a less morbid and more conservative surgical approach to restore knee stability. Primary repair is preferably performed in the acute setting because of better healing capacity and tissue quality. We present the surgical technique of arthroscopic primary ACL repair with suture anchors in patients with proximal tears and excellent tissue quality

Arthroscopic Primary Anterior Cruciate Ligament Repair With Suture Augmentation

Historically, poor results of open primary repair of anterior cruciate ligament (ACL) injuries have been reported. In hindsight, however, appropriate patient selection (i.e. proximal tears and good tissue quality) was not performed, because it has recently been recognized that good outcomes of primary ACL repair are possible when selectively performed in patients with proximal tears and good tissue quality. Moreover, with modern-day advances, arthroscopic primary repair can be an excellent treatment option for patients with proximal tears. Preserving the native ACL has several advantages, including maintaining native proprioceptive function and biology. The procedure is also minimally invasive and prevents the need for formal ACL reconstruction. Recently, it has been suggested that additional suture augmentation of the primary repair technique may be beneficial for protecting ligament healing during early range of motion. In this Technical Note, we present the surgical technique of arthroscopic primary repair with suture augmentation for patients with proximal ACL tears

Arthroscopic Primary Posterior Cruciate Ligament Repair With Suture Augmentation

Isolated posterior cruciate ligament (PCL) injuries are relatively rare and PCL injuries most commonly occur in the setting of multiligamentous knee injuries. PCL injuries can be treated with primary repair, which has the advantages of preserving the native tissue, maintaining proprioception, and minimal invasive surgery when compared with reconstruction surgery. Historically, primary repair of PCL injuries was performed in all tear types using an open approach, and, although the subjective outcomes were relatively good, patients often had residual laxity. Modern advances and increasing knowledge could improve the outcomes of PCL repair. With magnetic resonance imaging patients with proximal tears and sufficient tissue quality can be selected, and with arthroscopy and suture anchors minimal invasive surgery with direct fixation can be performed. Furthermore, with suture augmentation the healing of the repaired PCL can be protected and the residual laxity can be prevented. In this Technical Note, we describe the surgical technique of arthroscopic primary repair of proximal PCL tears with suture anchors and suture augmentation. The goal of arthroscopic primary repair is the preservation of the native PCL using a minimally invasive method and subsequent protection of this repair using suture augmentation

Postoperative Magnetic Resonance Imaging following Arthroscopic Primary Anterior Cruciate Ligament Repair

Introduction. Recently, there has been a resurgence of interest in arthroscopic primary anterior cruciate ligament (ACL) repair. To date, no studies have assessed the role of postoperative magnetic resonance imaging (MRI) on the status and maturation of the repaired ligament. The goal of this study was therefore to assess (I) the accuracy of MRI on rerupture of the repaired ligament and (II) the maturation of the repaired ACL. Methods. All postoperative MRIs of patients that underwent arthroscopic primary ACL repair were included. A musculoskeletal radiologist, blinded for MRI indication, surgery-MRI time interval, and clinical stability, retrospectively assessed the ligament continuity and graded ligament maturation as hypointense (similar to intact PCL), isointense (>50% similar to PCL), or hyperintense (<50% similar to PCL). Results. Thirty-seven MRIs were included from 36 patients. Mean age was 30 years (range: 14–57 years), and mean surgery-MRI interval was 1.5 years (range: 0.1–4.9 years). The radiologist recognized 6 out of 8 reruptures and 26 out of 29 intact ligaments (sensitivity 75%, specificity 90%, and accuracy 86%). Ligaments in the first year were more often hyperintense than after one year (60% vs. 11%, p=0.02), most often isointense (60%) between one and two years, and more often hypointense after two years than before two years (56% vs. 10%, p=0.03). Conclusion. Postoperative MRI was found to accurately predict the rerupture of the primarily repaired ACL. Furthermore, it can be expected that the repaired ligament is hyperintense within the first year, while the signal becomes similar to the intact PCL after two years

Multiligament Repair With Suture Augmentation in a Knee Dislocation With Medial-Sided Injury

Knee dislocations often result in a severe multiligament injured knee (MLIK) with complex instability. Multiligament reconstruction can successfully restore knee stability and is commonly recommended, although surgical morbidity is induced by graft harvesting and tunnel drilling, and convergence of multiple tunnels can complicate the surgery. Therefore, as an alternative, primary repair of knee ligaments is currently reconsidered. The main advantages of primary repair consist of tissue preservation and decrease of surgical morbidity, which might improve knee functionality. Techniques in which avulsed ligaments are reapproximated to their anatomic origin have resulted in good clinical outcomes in selected patients over the past decade. More recently, repaired ligaments have been augmented with suture tape, to protect them from excessive stretch, which can improve healing and allows early rehabilitation. The surgical technique of primary repair in the multiligament injured knee has not yet been described. The purpose of this Technical Note is to explain suture augmented primary repair in KDIII-M injury, including the anterior cruciate ligament, posterior cruciate ligament, and medial collateral ligament

Primary Repair of the Lateral Collateral Ligament Using Additional Suture Augmentation

Injuries to the lateral collateral ligament (LCL) most commonly occur with concomitant cruciate ligament tears. Over the past decade, there has been increased interest in anatomic reconstruction of the posterolateral corner (PLC). Not much attention has been paid to anatomic primary LCL repair given the historically high failure rates of primary repair of lateral sided knee ligaments, but better outcomes can now be expected because of recent developments in additional suture augmentation. The purpose of this Technical Note is to describe the surgical technique of primary distal LCL repair using suture augmentation. Using this procedure, the native ligament is preserved while allowing early mobilization as suture augmentation is protective of the repaired ligament