Gasless endoscopic thyroidectomy via an anterior chest wall approach using a flap-lifting system

PURPOSE: Endoscopic thyroidectomy (ET) requires a proper working space for adequate visualization of anatomical structures and proper instrument manipulation. The purpose of this prospective study was to estimate the feasibility and safety of ET using an anterior chest wall approach without gas insufflation. MATERIALS AND METHODS: The working space was created under a direct and endoscopic view through a 3-cm incision on the anterior chest wall. A retracting device was then inserted to establish the working space, and subsequent procedures were performed endoscopically. All data were reviewed using a prospective database. RESULTS: We performed 30 ETs in patients with benign thyroid tumors from December 2003 to December 2005. The procedures were completed successfully in 29 patients (mean operative time: 160.6 min; range: 90-345 min). One patient with ET was converted to open thyroidectomy secondary to substernal extension of the tumor. None of the patients developed permanent postoperative hypocalcemia or recurrent laryngeal nerve paralysis. Three patients exhibited some degree of transient recurrent laryngeal nerve palsy. CONCLUSION: These data suggest that gasless ET using an anterior chest wall approach is safe and feasible in selected patients for treating benign thyroid tumors. This technique may offer good operative working space when performed by surgeons with relatively low-volume ET practices.     

Evaluating computer-aided detection algorithms

Computer-aided detection (CAD) has been attracting extensive research interest during the last two decades. It is recognized that the full potential of CAD can only be realized by improving the performance and robustness of CAD algorithms and this requires good evaluation methodology that would permit CAD designers to optimize their algorithms. Free-response receiver operating characteristic (FROC) curves are widely used to assess CAD performance, however, evaluation rarely proceeds beyond determination of lesion localization fraction (sensitivity) at an arbitrarily selected value of nonlesion localizations (false marks) per image. This work describes a FROC curve fitting procedure that uses a recent model of visual search that serves as a framework for the free-response task. A maximum likelihood procedure for estimating the parameters of the model from free-response data and fitting CAD generated FROC curves was implemented. Procedures were implemented to estimate two figures of merit and associated statistics such as 95% confidence intervals and goodness of fit. One of the figures of merit does not require the arbitrary specification of an operating point at which to evaluate CAD performance. For comparison a related method termed initial detection and candidate analysis was also implemented that is applicable when all suspicious regions are reported. The two methods were tested on seven mammography CAD data sets and both yielded good to excellent fits. The search model approach has the advantage that it can potentially be applied to radiologist generated free-response data where not all suspicious regions are reported, only the ones that are deemed sufficiently suspicious to warrant clinical follow-up. This work represents the first practical application of the search model to an important evaluation problem in diagnostic radiology. Software based on this work is expected to benefit CAD developers working in diverse areas of medical imaging.     

Predominance of community-associated methicillin-resistant Staphylococcus aureus strains carrying staphylococcal chromosome cassette mec type IVA in South Korea

Studies on the molecular epidemiologic characteristics of methicillin-resistant Staphylococcus aureus (MRSA) strains have demonstrated their genetic and geographical diversity. In addition, it has been reported that there are genetic differences between community-associated (CA) and health care-associated (HA) MRSA strains. Therefore, we investigated the major epidemiologic characteristics of CA MRSA isolates in South Korea and compared them with those of HA MRSA strains. Distributions of staphylococcal chromosome cassette mec (SCCmec) types and other molecular features, including the Panton-Valentine leukocidin (PVL) gene, were studied in 138 invasive MRSA isolates. Multiplex type IVA SCCmec was identified as the major CA MRSA infection type (53.1%), with a significantly higher prevalence than in HA MRSA (P < 0.001). One major group of type IVA strains carried a larger atypical class B mec element and new subtypes of ccrA2 (96% amino acid homology). The PVL gene was detected in one USA300-like isolate only. Seven major clone types determined by combinational grouping (genetic background SCCmec typing) showed representative patterns of antimicrobial susceptibilities. We concluded that less multi-drug-resistant strains of clone types B-I and D-1 (genetic background, B and D complexes; type IVA SCCmec) predominate in CA MRSA and that international PVL-positive strains have not spread in South Korea as yet.     

Non-constraining sleep/wake monitoring system using bed actigraphy

This paper introduces a new method, bed actigraphy (BACT) for user-friendly sleep-wake monitoring. BACT provides a non-intrusive acquisition of activity data, and in particular does not require that sensors be attached to the subject’s body. The system consists of four load-sensing cells supporting the bed, an A/D converter, and a microcontroller with appropriate software. The performance of BACT was compared to that of standard polysomnography (PSG) recordings and wrist-worn actigraphy (ACT). Ten normal volunteers underwent overnight PSG recordings and were examined simultaneously with BACT and ACT. An automatic scoring algorithm scored each 30-s epoch of the BACT recordings for either ‘Wake’ or ‘Sleep.’ A sleep specialist manually scored the PSG recordings, and the results were divided into ‘Wake’ and ‘Sleep’ categories. The three methods showed a significant correlation when compared with in the contingency test. The mean epoch-by-epoch agreements between the BACT and PSG, ACT and PSG, and BACT and ACT recordings were 95.2, 92.9, and 94.3%, respectively. The mean absolute differences in sleep percentage (SP) between them were 1.8 ± 0.82, 3.4 ± 1.45, and 1.9 ± 1.16 %, respectively. BACT differentiation of the ‘Wake’ and ‘Sleep’ stages proved to be sufficiently robust, and its results were comparable to PSG analysis. This finding supports the experimental and clinical value of bed-activity monitoring during sleep.     

Matrix metalloproteinase-9 activity is associated with poor prognosis in T3-T4 node-negative colorectal cancer

Reversion-inducing cysteine-rich protein with Kazal motifs (RECK) is a novel membrane-anchored matrix metalloproteinase (MMP) inhibitor. RECK, MMP-2, and MMP-9 are believed to play crucial roles in tumor progression. This study was designed to examine the prognostic value of RECK, MMP-2, and MMP-9 in conjunction with other clinicopathologic factors in patients of T3-T4 node-negative colorectal cancer. RECK and MMP expression was observed using immunohistochemical analysis of the primary tumor from 89 patients with curatively resected T3-4 N0 colorectal cancer retrospectively. High RECK expression was observed in 51 cases, whereas expression was low in the other 38 cases. MMP-2 and MMP-9 expression was positive in cancer cells in 24 and 33 cases, respectively. RECK and MMP-2 expression was not significantly associated with any clinicopathologic factors. However, expression of MMP-9 was correlated with tumor location. A statistically significant inverse correlation was found between RECK and MMP-2 expression, and a statistically significant correlation was found between MMP-2 and MMP-9 expression. However, no association between RECK and MMP-9 expression was observed. Univariate analysis demonstrated that rectal tumor location, preoperative carcinoembryonic antigen more than 5 ng/mL, positive lymphatic invasion, less than 12 dissected lymph nodes, and positive MMP-9 expression were poor prognostic factors of disease-free survival. A multivariate analysis confirmed that enhanced MMP-9 expression was an independent and significant factor for prediction of a poor prognosis. In addition, positive lymphatic invasion and less than 12 dissected lymph nodes were significant negative prognostic factors. In conclusion, MMP-9 status represents a novel prognostic factor in evaluation of T3-T4 node-negative colorectal cancer.     

Abnormal fragile histidine triad (Fhit) expression in invasive cervical adenocarcinoma: association with tumor aggressiveness

The fragile histidine triad (FHIT) gene is a candidate tumor suppressor gene. Aberrant expression of the encoded protein and inactivation of FHIT correlate with several clinicopathological parameters in various tumor types, including cervical cancer, but Fhit expression has rarely been studied in cervical adenocarcinoma. We assessed Fhit protein expression in 35 surgical specimens of invasive adenocarcinomas of the uterine cervix and investigated whether expression alteration on immunohistochemistry staining is associated with important clinicopathological features. Considerably reduced or absent Fhit staining was observed in 11 cancers (31.4%). By univariate analysis, Fhit protein expression was significantly associated with nodal status (P = .002), histologic grade (P = .000), and International Federation of Gynecology and Obstetrics stage (P = .032). Depth of invasion, tumor size, or parametrial invasion did not show important association with Fhit. Lymph node status, International Federation of Gynecology and Obstetrics stage, and histologic grade are known prognostic factors of cervical adenocarcinoma, and Fhit status on immunohistochemistry staining demonstrated significant association with tumor aggressiveness. Staining of biopsy specimens for Fhit is worthy of study as a prognostic tool.     

Identification of a novel HLA-B*58 allele, B*5813, by sequence-based typing of DNA from Korean baby cord blood

The novel HLA-B*5813 allele was identified in the cord blood of a Korean baby by sequence-based typing. This allele shows a sequence identical to that of HLA-B*5801, except for a nucleotide substitution that changes GAG to AAG at codon 128, resulting in an amino acid change from glutamic acid to lysine in the protein.