Comparison Among Clark's, Breslow's, and TNM classifications for cutaneous head and neck malignant melanoma

This retrospective study was carried out to assess the prognostic value of three classification systems used for staging cutaneous head and neck malignant melanoma (CHNME). Fifty-three patients with histologically proven CHNME were analyzed. Thirty patients were never treated before admission, whereas 23 (43.4%) had a second radical resection of the primary tumor location, 9 (17%) had neck nodes, none had distant metastasis, and all had a minimum of 5 years of follow-up. Results show that T-stage is the most important clinical prognostic parameter, whereas Clark's and Breslow's classifications have lower impact in defining prognosis. Sites of primary tumor determines different clinical outcomes, but this does not reach statistically significant values. A second surgery on the primary tumor location is possible and is effective toward survival. No statistical differences were noted between the previously untreated and treated groups. Neck nodes have to be removed with neck dissection, and this regimen can improve the clinical outcome; however, only 40% of neck positive patients survive more than 5 years.     

Using virtual reality to maintain surgical skills during periods of robotic surgery inactivity

Periodic practice is needed for newly trained robotic surgeons to maintain skills during periods of robotic inactivity. The current study was performed to determine whether virtual robotic skill maintenance can serve as an adequate substitute for practice on a surgical robot. Eleven surgical residents with no prior robotic training were trained to a level of robotic proficiency with inanimate models, including a needle driving pad, a running suture pad, and ring placement on a rocking peg board. After reaching proficiency, each resident was tested on a complex tissue closure task. For the next 8 weeks, the only robotic activity was biweekly virtual robotic skills maintenance. After 8 weeks, the residents performed the tissue closure task twice with the robot, followed by evaluation on the inanimate models used to reach proficiency. Repeated-measures statistical analyses were used to compare between the three tissue closure trials and between the final test at week 0 and the evaluation at week 8 for the other inanimate models. Time to complete the tissue closure task was more than 20 % lower for the second evaluation at 8 weeks than for the other two trials (p < 0.05). Residents maintained their skills for needle driving, but times for suture running and rocking peg board increased by more than 20 % at 8 weeks (p < 0.01). Virtual practice shows promise for maintaining robotic skills. Following a warm-up period, some skills may actually improve with biweekly virtual practice, but skill retention is selective, so further improvements are needed.     

Immunohistochemical localization of two types of choline acetyltransferase in neurons and sensory cells of the octopus arm

Cholinergic structures in the arm of the cephalopod Octopus vulgaris were studied by immunohistochemistry using specific antisera for two types (common and peripheral) of acetylcholine synthetic enzyme choline acetyltransferase (ChAT): antiserum raised against the rat common type ChAT (cChAT), which is cross-reactive with molluscan cChAT, and antiserum raised against the rat peripheral type ChAT (pChAT), which has been used to delineate peripheral cholinergic structures in vertebrates, but not previously in invertebrates. Western blot analysis of octopus extracts revealed a single pChAT-positive band, suggesting that pChAT antiserum is cross-reactive with an octopus counterpart of rat pChAT. In immunohistochemistry, only neuronal structures of the octopus arm were stained by cChAT and pChAT antisera, although the pattern of distribution clearly differed between the two antisera. cChAT-positive varicose nerve fibers were observed in both the cerebrobrachial tract and neuropil of the axial nerve cord, while pChAT-positive varicose fibers were detected only in the neuropil of the axial nerve cord. After epitope retrieval, pChAT-positive neuronal cells and their processes became visible in all ganglia of the arm, including the axial and intramuscular nerve cords, and in ganglia of suckers. Moreover, pChAT-positive structures also became detectable in nerve fibers connecting the different ganglia, in smooth nerve fibers among muscle layers and dermal connective tissues, and in sensory cells of the suckers. These results suggest that the octopus arm has two types of cholinergic nerves: cChAT-positive nerves from brain ganglia and pChAT-positive nerves that are intrinsic to the arm.     

Healing of Fresh Extraction Sockets Filled with Bioactive Glass Particles: Histological Findings in Humans

Purpose: The aim of the present study was to histologically evaluate fresh human sockets filled with bioactive glass after 6 months of healing. Materials and Methods: In 13 patients, 32 single extraction sites in the anterior area underwent socket ridge preservation procedure (RPP) with a bioactive glass (BioRestore?, Inion Oy, Tampere, Finland). At implant installation, 22 bone cores were trephined out and processed for histomorphometric and immunohistochemical analysis. Results: Newly formed immature bone around residual particles of bioactive glass was found in all 22 biopsies. The histomorphometry of the amount of bone, provisional matrix, and residual graft returned a mean ± SD value of 54 ± 31%, 37.9 ± 25.6%, and 8.1 ± 7.8, respectively, 6 months after RPP. Conclusion: The use of this grafting material in fresh extraction sockets appears to delay the healing processes of the alveolar bone; therefore, its indication as a material for RPP when implant placement is considered within 6 months after extraction should be revised.