Development of Automated Delivery Quality Assurance Analysis Software for Helical Tomotherapy.

BACKGROUND: To develop a fully automated in-house gamma analysis software for the "Cheese" phantom-based delivery quality assurance (QA) of helical tomotherapy plans. METHODS: The developed in-house software was designed to automate several procedures, which need to be manually performed using commercial software packages. The region of interest for the analysis was automatically selected by cropping out film edges and thresholding dose values (>10% of the maximum dose). The film-measured dose was automatically aligned to the computed dose using an image registration algorithm. An optimal film scaling factor was determined to maximize the percentage of pixels passing gamma (gamma passing rate) between the measured and computed doses (3%/3 mm criteria). This gamma analysis was repeated by introducing setup uncertainties in the anterior-posterior direction. For 73 tomotherapy plans, the gamma analysis results using the developed software were compared to those analyzed by medical physicists using a commercial software package. RESULTS: The developed software successfully automated the gamma analysis for the tomotherapy delivery quality assurance. The gamma passing rate (GPR) calculated by the developed software was higher than that by the clinically used software by 3.0%, on average. While, for 1 of the 73 plans, the GPR by the manual gamma analysis was higher than 90% (pass/fail criteria), the gamma analysis using the developed software resulted in fail (GPR < 90%). CONCLUSIONS: The use of automated and standardized gamma analysis software can improve both the clinical efficiency and veracity of the analysis results. Furthermore, the gamma analyses with various film scaling factors and setup uncertainties will provide clinically useful information for further investigations.

Risk factors for sepsis in Korean trauma patients.

PURPOSE: Sepsis in severely injured patients is one of the leading causes of death in hospitals. The incidence of and risk factors for sepsis after trauma have been studied outside, but not within Korea. Therefore, this study investigated the incidence of sepsis and the independent risk factors for sepsis in moderately to severely injured patients in Korea. METHODS: The electronic medical records of patients who visited the emergency department from January 2010 to December 2012 were reviewed retrospectively. Patients older than 18 years of age with an Injury Severity Score (ISS) greater than or equal to nine points were included. RESULTS: A total of 183 patients met the study inclusion criteria. The median ISS was 14 (range 9-17) points and 15 (8 %) patients developed sepsis. The patients' age [adjusted OR, 1.053; 95 % confidence intervals (CI), 1.015-1.094], ISS (adjusted OR, 1.114; 95 % CI, 1.046-1.187), and emergency surgery (adjusted OR, 3.727; 95 % CI, 1.051-13.221) were independent risk factors for post-traumatic sepsis. CONCLUSIONS: Among the risk factors identified in the literature, our research confirmed only the patients' age and ISS as risk factors for sepsis after trauma, and, additionally, identified emergency surgery as a risk factor in Korean patients. Therefore, trauma patients who have any of the risk factors mentioned above have a high risk of post-traumatic sepsis, which requires certain precautionary clinical measures.

Solution immersed silicon (SIS)-based biosensors: a new approach in biosensing.

A novel, solution immersed silicon (SIS)-based sensor has been developed which employs the non-reflecting condition (NRC) for a p-polarized wave. The SIS sensor's response is almost independent of change in the refractive index (RI) of a buffer solution (BS) which makes it capable of measuring low-concentration and/or low-molecular-weight compounds.

Decision support for ecological river rehabilitation using fish habitat database.

After the recent success of several river rehabilitation projects including the Cheong-gye river case, a large number of local governments have been promoting their own projects in Korea. Most of the projects are aimed at securing the soundness of aquatic ecosystems according to the guidelines presented by the Korea Ministry of Environment. However, there is no clear guidance for the management goals of water quality and quantity. In this study, we have made an attempt to construct a habitat database (DB) for each domestic freshwater fish species. The fish population, and physical and physicochemical properties of the habitat of 70 domestic freshwater fish species were investigated using field monitoring data. After the statistical processing, the inhabitable range and optimal range of each species were suggested. Furthermore, based on the DB, a decision support system for ecological river restoration and rehabilitation has been developed, and applied for field tests. It became clear that the decision support procedure based on the fish habitat DB is useful in the planning stage of river rehabilitation projects to select the flagship fish, to decide the restoration goals considering their appropriate habitat and to suggest the optimum quantitative combination of each available water resource.

Submitral left ventricular aneurysm of ischemic origin: report of two surgical cases.

Submitral left ventricular aneurysm has been exclusively recognized in the young African population and its occurrence in other than black Africans is rarely reported. Here we describe two surgical cases of submitral left ventricular aneurysm in Asian elderly persons. Although the aneurysms were typically located beneath the posterior mitral valve leaflet, we could identify diseased coronary arteries as well, unlike the reports in the literature asserting that this type of aneurysm occurs in the absence of coronary disease. The possible racial difference with regard to the etiology is addressed.

Comparison of 25- and 23-gauge sutureless microincision vitrectomy surgery in the treatment of various vitreoretinal diseases.

PURPOSE: To compare the effectiveness and safety of 25- and 23-gauge sutureless microincision vitrectomy surgery (MIVS) in the management of various vitreoretinal diseases. METHODS: Eighty-five consecutive patients undergoing sutureless vitrectomy during January to April 2008 were randomized to either 25- or 23-gauge MIVS. Data collected prospectively included best-corrected visual acuity (BCVA), operation time, postoperative visual recovery, postoperative anterior segment change, and complications. RESULTS: The most common indications for MIVS were macular hole, macular pucker, vitreous haemorrhage, and diabetic traction retinal detachment. Mean operation times of the 25-gauge (n=38) and 23-gauge groups (n=47) were 33.68 and 34.47 min, respectively (P=0.942). Mean BCVA improved significantly in both the 25- and 23-gauge groups when measured 3-month postoperatively. There was no between-group difference in either the degree or the rate of postoperative visual recovery. Seven patients in the 23-gauge group, compared with three in the 25-gauge group, required suturing of sclerotomy at the end of the surgery. No patients in either group developed postoperative wound leakage or endophthalmitis. CONCLUSION: Our prospective study suggests that, within the limited indications, both 25- and 23-gauge MIVS are equally effective, with similar safety profiles. Gauge selection thus may be made according to a surgeon's preference and the availability of appropriate instruments.

Central lymph node metastases in unilateral papillary thyroid microcarcinoma.

BACKGROUND: The indications for and appropriate extent of prophylactic central lymph node (CLN) dissection for clinically node-negative patients with unilateral papillary thyroid microcarcinoma (PTMC) are unknown. METHODS: The frequency, patterns and predictive factors for CLN metastases in 86 patients with unilateral PTMC and a clinically node-negative neck were analysed with respect to age and sex; metastasis, age, completeness, invasiveness, size (MACIS) score; tumour size; number and location of tumours; presence of ipsilateral CLN metastases; and presence of lymphovascular or capsular invasion. All patients underwent total thyroidectomy and CLN dissection. RESULTS: Twenty-seven (31 per cent) of 86 patients had metastatic CLNs: 18 ipsilateral and nine bilateral. Univariable analysis suggested male sex and tumour size greater than 0.5 cm to be significant factors in predicting ipsilateral CLN metastases. Only ipsilateral nodal positivity was a significant predictor of contralateral CLN metastases in multivariable analysis (P = 0.007). CONCLUSION: CLN metastases are relatively common in PTMC.

Purification of circular YACs from yeast cells for DNA sequencing.

We describe a method for the purification of circular yeast artificial chromosome (YAC) DNA 120-150 kilobases (kb) in size that is of sufficient quantity and quality for restriction enzyme analysis and DNA sequencing. This method preferentially enriches for circular YAC DNA and avoids the time-consuming step of centrifugation in CsCl--ethidium bromide (EtBr) gradients. We applied this method to the purification of circular YACs carrying DNA segments that are extremely unstable in E. coli, including those that correspond to GAP2 and GAP3 on human chromosome 19. We showed that YAC DNA (GAP2 and GAP3) purified using this new method is clearly resolved in EtBr-stained gels. The sequence of YAC-GAP3 was obtained, representing the first GAP clone sequenced in YAC form. At present, it is estimated that there are more than 1000 gaps in the human genome that cannot be cloned using bacterial vectors. Thus, our new method may be very useful for completing the last stage of the human genome project.

Reconstruction of basement membrane in skin equivalent; role of laminin-1.

To reconstruct the basement membrane in a skin equivalent, the epidermodermal interface was coated with porcine type IV collagen and mouse laminin-1 at various ratios before keratinocyte seeding. Laminin-1, a component of the basement membrane, induced massive infiltration of keratinocytes into the dermal equivalent, while type IV collagen induced discrete demarcation between dermal and epidermal compartments without any infiltrating cells. Immunohistochemical staining indicated that the laminin-induced infiltrating cells expressed endogenous type IV collagens at the cell periphery, which were not incorporated into the basement membrane structure. The infiltrating cells did not express fibronectin receptor alpha5beta1 integrin but showed MMP-9 secretion and cell surface associated MMP-2. However, when laminin-1 was preincubated with type IV collagen, laminin-1-induced keratinocyte infiltration as well as MMP-9 induction were almost completely suppressed to basal levels. Therefore, replenishment of the type IV collagen lattice seemed to cause laminin-stimulated cells to anchor to the lattice, in a similar manner to the basal cells on the basement membrane of normal skin. Our study suggests that the molar ratio of basement membrane components may determine the behavior of basal cells within the wound healing microenvironment, which is probably regulated either by extracellular matrix deposition or degradation.

Comparison of diameter and perimeter methods for tumor volume calculation.

PURPOSE: Lesion volume is often used as an end point in clinical trials of oncology therapy. We sought to compare the common method of using orthogonal diameters to estimate lesion volume (the diameter method) with a computer-assisted planimetric technique (the perimeter method). METHODS: Radiologists reviewed 825 magnetic resonance imaging studies from 219 patients with glioblastoma multiforme. Each study had lesion volume independently estimated via the diameter and perimeter methods. Cystic areas were subtracted out or excluded from the outlined lesion. Inter- and intrareader variability was measured by using multiple readings on 48 cases. Where serial studies were available in noncystic cases, a mock response analysis was used. RESULTS: The perimeter method had a reduced interreader and intrareader variability compared with the diameter method (using SD of differences): intrareader, 1.76 mL v 7.38 mL (P < .001); interreader, 2.51 mL v 9.07 mL (P < .001) for perimeter and diameter results, respectively. Of the 121 noncystic cases, 23 had serial data. In six (26.1%) of those 23, a classification difference occurred when the perimeter method was used versus the diameter method. CONCLUSION: Variability of measurements was reduced with the computer-assisted perimeter method compared with the diameter method, which suggests that changes in volume can be detected more accurately with the perimeter method. The differences between these techniques seem large enough to have an impact on grading the response to therapy.

Depletion of intracellular zinc and copper with TPEN results in apoptosis of cultured human retinal pigment epithelial cells.

PURPOSE: Although zinc deficiency may contribute to the pathogenesis of age-related macular degeneration, how it leads to retinal pigment epithelium (RPE) degeneration is unknown. To investigate this, cultured human RPE cells were rendered zinc depleted with a membrane-permeant metal chelator, N,N,N',N-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN), and the resultant cytopathic changes were examined. METHODS: RPE cell degeneration was examined with light microscopy, TdT-mediated dUTP nick end labeling (TUNEL) staining, Hoechst dye staining, and electron microscopy and quantified with cell counting or lactate dehydrogenase release assay. The effect of sublethal zinc depletion on the vulnerability of RPE cells to UV irradiation or hydrogen peroxide (H(2)O(2)) exposure, was studied in cultures without or with pretreatment with low-concentration TPEN. RESULTS: Exposure to 1 to 4 microM TPEN for 48 hours induced RPE cell death in a concentration-dependent manner. Features of apoptosis such as membrane blebbing, chromatin condensation, nuclear fragmentation, and caspase-3 activation, accompanied the TPEN-induced cell death. Addition of equimolar zinc or copper completely reversed TPEN-induced apoptosis, whereas addition of iron had no effect. As in apoptosis of several other cell types including neurons, a protein synthesis inhibitor as well as caspase inhibitors blocked TPEN-induced apoptosis. On the contrary, at sublethal concentrations, TPEN increased the vulnerability of RPE cells to subsequent UV irradiation but not to H(2)O(2) exposure. CONCLUSIONS: The present results suggest that depletion of intracellular zinc and copper, but not copper alone, may be harmful to RPE cells, directly inducing apoptosis or indirectly increasing vulnerability of RPE cells to UV injury. The present culture model may be useful for gaining insights into the mechanisms of zinc depletion-associated RPE cell degeneration.

The distribution of soiling by coarse particulate matter in the museum environment.

Soiling measurements are needed to address strategies to control dust and determine its sources. There is no widely recognized method for dust monitoring in museums, but we used sticky samplers to collect deposited coarse particulate matter, and both manual microscopic observations and image analysis for determining soiling potential in the museum environment. We adopt fractional area covered by deposited particles as a surrogate for soiling and the covering rate (unit: s-1) as a measure of the rate of soiling. It was clear that visitor flow was a major contributor to soiling, such that soiling mechanisms in different museums could be compared after measurements were normalised on a per capita basis. The proximity of visitors to objects was another important factor with the soiling declining with distance from visitor pathways (a half-distance of about 0.5 m), which suggests soiling of objects on open display could be reduced by increasing the distance from visitors.

Myositis ossificans of the chest wall simulating malignant neoplasm.

Myositis ossificans originating from the chest wall is extremely rare. We report a case of myositis ossificans occurring in a young woman with progressive painful swelling in the chest wall. Preoperative examination suggested a malignant neoplasm originating from soft tissue. Although rare, myositis ossificans is one of the potential causes of painful swelling in the chest wall, and can be mistaken for a malignant neoplasm.

Increases in intraocular pressure during hemodialysis in eyes during early postvitrectomy period.

BACKGROUND AND OBJECTIVES: To identify risk factors for intraocular pressure (IOP) increases during hemodialysis (HD) in the early postoperative period following pars plana vitrectomy (PPV). PATIENTS AND METHODS: Comparisons of 36 vitrectomized eyes of 22 diabetics undergoing maintenance HD with those of 138 eyes of 69 nonoperated patients. Serial IOPs were measured before PPV, after PPV/before dialysis, and during dialysis. Serum osmolarity and blood pressure were also recorded. RESULTS: In 20 of 36 operated eyes (55.6%) and 18 of 138 nonoperated eyes (13.0%) IOP was increased (> or =4 mm Hg) during HD. In the operated group, marked increases (> or =7 mm Hg) were noted in 9 eyes and ocular pain in 5 eyes. Eyes with pre-existing outflow obstruction and/or acute postoperative outflow compromise carried high risks. No correlation with changes in serum osmolarity or blood pressure was found. CONCLUSION: Monitoring of IOP during HD seems warranted when diabetics with pre-existing outflow obstruction and/or postoperative outflow compromise, undergo HD following PPV.

Management of persistent or recurrent pneumothorax with a two millimeter mini-videothoracoscope.

The aim of this study was to assess whether a 2 mm mini-videothoracoscope could be used as a conventional videothoracoscope in the management of pneumothorax. Thirty patients of ages from 15 to 35 years with recurrent or persistent pneumothorax were involved in this study. The subjects consisted of 27 males and three females. The indications for videothoracoscopic surgery were ipsilateral recurrent pneumothorax in 12 (40%), persistent air leakage in 15 (50%), visible bullae in 2 (6%), and 1 bilateral pneumothorax (3%). The mean operation time was 42.9+/-12.9 min. The average number of uses for Endo-GIA was 1.9+/-1.3 times and chest tube indwelling time was 3.8+/-2.7 days. The average amount of keptoprofen (100 mg/2 mL/ampule) used on the first postoperative day was 1.2+/-1.1 ampules. No parenteral opioids were given to the patients for pain control after the procedures. After a follow up of 8 to 20 months, there was only one recurrence among the patients. In conclusion, a 2 mm videothoracoscope, in selective cases, can be successfully used as conventional videothoracoscope to manage persistent or recurrent pneumothorax with cosmetically excellent results.

Depletion of intracellular zinc induces macromolecule synthesis- and caspase-dependent apoptosis of cultured retinal cells.

Although zinc deficiency may contribute to age-related macular degeneration (ARMD), the pathogenic mechanism is as yet uncertain. In light of evidence that cellular zinc depletion induces apoptosis in cortical neurons and thymocytes, in the present study, we examined the possibility that the same phenomenon occurs also in retinal cells. Exposure of primary retinal cell cultures to 1-3 microM of a cell membrane-permeant zinc chelator TPEN for 24 h induced concentration-dependent death of neurons, photoreceptor cells, and astrocytes. Addition of zinc or copper reversed TPEN toxicity to all cell components, indicating the particular involvement of zinc chelation in cell death. Consistent with apoptosis, oligonucleosomal DNA fragmentation and chromatin condensation accompanied, and the protein synthesis inhibitor cycloheximide blocked the TPEN-induced retinal cell death. During TPEN-induced retinal cell apoptosis, cleavage/activation of procaspase-1, but little of procaspase-3, was observed. Consistent with this finding, a broad-spectrum caspase inhibitor (zVAD-fmk) was significantly more protective than a caspase-3-selective inhibitor (DEVD-fmk). The present study has demonstrated that depletion of intracellular zinc is sufficient to induce macromolecule synthesis- and caspase-dependent apoptosis of cultured retinal cells. In light of the possibility that zinc depletion may contribute to the pathogenesis of ARMD, the current culture model may be a useful tool for the investigation of the mechanism of zinc depletion-induced retinal cell death.

Needle thoracic sympathectomy for essential hyperhidrosis: intermediate-term follow-up.

BACKGROUND: Essential hyperhidrosis is a condition with excessive sweating localized to certain part of the body. A definitive cure can be obtained by upper thoracic sympathectomy. METHOD: Between June and October 1997, 117 patients with essential hyperhidrosis underwent needle thoracoscopic sympathectomy. Of the 94 patients, 42 were men and 52 women. Their ages ranged from 14 to 63 years, with a mean age of 23 years. RESULTS: There were no mortality or life-threatening complications. Symptomatic improvement was found in 95.7%. Compensatory hyperhidrosis was found in 71.2% of the patients, but in these compensatory hyperhidrosis were mostly tolerable. CONCLUSIONS: This therapeutic procedure is minimally invasive and very effective. Further development of the new device and surgical technique are expected to follow.

Ethambutol-induced vacuolar changes and neuronal loss in rat retinal cell culture: mediation by endogenous zinc.

Ethambutol is an efficacious antituberculosis agent. However, its use has been limited by the occurrence of ocular toxicity. To investigate characteristics and possible mechanisms of ethambutol ocular toxicity, we used primary rat retinal cultures as a model. Primary rat retinal cultures were obtained from newborn Sprague-Dawley rats and used for experiments after maturation (DIV > or = 10). Cytopathologic changes were examined under light and electron microscopes. Thy-1 (a membrane glycoprotein expressed by retinal ganglion neurons)-containing neurons and gamma-aminobutyric acid (GABA)-ergic neurons were identified immunocytochemically. Exposure of retinal cultures for 24-48 h to ethambutol induced cytoplasmic vacuolar changes and neuronal loss. Vacuolar changes were partially reversible with the termination of ethambutol exposure. Of neurons, Thy-1(+) ganglion neurons were more vulnerable than GABA(+) neurons. Glutamate antagonists, an antioxidant (trolox), or cycloheximide, did not attenuate either vacuolar changes or neuronal loss. A cell-permeant zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) markedly attenuated vacuolar degeneration and neuronal loss, while the addition of zinc augmented both. In rat retinal cultures, ethambutol induces reversible vacuolar degeneration as well as irreversible neuronal loss, more preferentially of Thy-1(+) ganglion neurons. Contrary to the current theories, ethambutol-induced retinal cytotoxicity in the present study is mediated not by excitotoxicity or zinc deficiency but by a mechanism requiring intracellular zinc. In addition, features of the ethambutol-induced cell death were not consistent with those of apoptosis.

High vulnerability of GABA-immunoreactive neurons to kainate in rat retinal cultures: correlation with the kainate-stimulated cobalt uptake.

Like other areas of the central nervous system, the retina is highly vulnerable to ischemia. In particular, neurons in the inner nuclear layer, including gamma-amino butyric acid (GABA)-ergic amacrine neurons, are highly vulnerable. Since excitotoxicity is likely a major mechanism of ischemic retinal injury, using rat retinal cell culture, we examined whether GABAergic retinal neurons are differentially vulnerable to particular excitotoxins. The neuronal population as a whole, identified by anti-microtubule associated protein-2 (MAP-2) immunocytochemistry, was equally vulnerable to kainate, but more resistant to N-methyl-d-aspartate (NMDA) than cultured cortical neurons. Compared to Thy-1 immunoreactive neurons, GABA immunoreactive neurons were more vulnerable to kainate, but more resistant to NMDA neurotoxicity. Double staining of cultures with anti-GABA immunocytochemistry and the kainate-stimulated cobalt uptake method, revealed a close correlation between the two. However, unlike in other neuronal cells, there was no clear correlation between GluR2 immunoreactivity and the cobalt staining. The heightened vulnerability of GABAergic neurons to kainate, as compared to the general neuronal population, may be due to the calcium-permeable AMPA/kainate receptors they have, as identified functionally by the kainate-stimulated cobalt uptake staining. Since these neurons are preferentially injured in ischemia, AMPA/kainate receptor-mediated neurotoxicity may contribute significantly to ischemic retinal injury.