Application of Ultrasonic Nano Crystal Surface Modification into Nitinol Stent Wire to Improve Mechanical Characteristics / 의학물리

Phase transformation, superelastic characteristics and variation of surface residual stress were studied for Nitinol shape memory alloy through application of UNSM technology, and life extension methods of stent were also studied by using elastic resilience and corrosion resistance. Nitinol wire of Oslash1.778 mm showed similar surface roughness before and after UNSM treatment, but drawing traces and micro defects were all removed by UNSM treatment. It also changed the surface residual stress from tensile to compressive values, and XRD result showed less intensive austenite peak and clear martensite and additional R-phase peaks after UNSM treatment. Fatigue resistance could be greatly improved through removal of surface defects and rearrangement of surface residual stress from tensile to compressive state, and development of surface modification system to improve not only bio-compatability but also resistance to corrosion and wear will make it possible to develop vascular stent which can be used for circulating system diseases which run first cause of death of recent Koreans.

Treatment of Lung Cancer in Patients Aged 40 years or Less / 대한흉부외과학회지

BACKGROUND: The prognosis for young patients generally considered to be poor. The purpose of this study was to determined whether the clinical characteristics and the survival rate in young lung cancer patients after surgical treatment differs from that in older patients. MATERIAL AND METHOD: Of 526 patients, 28(5.3%) were 30 to 40 years old. We studied the clinical characteristics and prognosis of 28 patients aged 40 years or less(Group 1), in whom primary lung cancer was diagnosed and operated between 1990 and 1997, and compared them with those 498 patients aged more than 40 years(Group 2). RESULT: The differences in sex ratio that were higher for women in Group 1, but there was no significant difference (p=0.297). The percentages for smokers and symptoms in Group 1 were significantly less than in Group 2.(p=0.049, p=0.008). Adenocarcinoma was significantly more common (p=0.018) and squamous cell diagnosed was diagnosed as stage IIIb or stage IV in 9 patients(32.1%), while 12.0% of the patients older than 40 years of age had either stage IIIb or stage IV(p=0.002). The 5-year survival rate was 41.3% in Group 1 ; 37.7% in Group 2, and the median survival time was 24.3 months in Group 1 ; 27.0 months is Group 2. There were no significant difference in survival between two age groups(p=0.808). CONCLUSIONS: Younger patients have more adenocarcinoma, however have less squamous cell carcinoma, less symptoms and less smoking history. Although younger patients tended to have more advanced disease and less complete resection rate, the recurrence and the long term survival in these patients did not differ that of older patients.

Prognostic Factors Affecting Long Term Survival after Operation in Metastatic Lung Cancer / 대한흉부외과학회지

BACKGROUND: Many institutes are interested in lung metastatectomy than before because of the improved long term survival, low mortality, and low morbidity after lung metastatectomy. However, prognostic factors affecting long term survival are controversial. We attempt to analyze the prognostic factors affecting retrospectively by comparing the results of lung metastasectomy. MATERIAL AND METHOD: Between Jan. 1990 and Dec. 1997, 74 operations were taken in 63 patients with pulmonary metastases in various primary sites. We analyzed the postoperative long term survival according to sex, cell type, laterality, disease free interval(DFI), operation, the number of metastases, and the size of the largest metastasis. RESULT: There were 27 male and 36 female patients. Sex did not appeared to affect survival time(p=0.849). The primary tumor was carcinoma in 32, sarcoma in 28, and others in 3. Cell type, considering carcinoma and sarcoma, did not relate to survival time(p=0.071). DFI had no influence on the outcome(p=0.902). The type of operative procedure had no influence on the outcome(p=0.556). The laterality of metastases, 47 unilateral(74.6%) and 16 bilateral(25.4%), had no influence on the outcome(p=0.843). The number of metastases excised(one, two or three, four or more) did not appear to affect survival(p=0.263). The size of largest metastasis(30mm) did not appear to affect survival(p=0.751). Previous factors were evaluated in both the carcinoma and sarcoma patients respectively. DFI was the only significant prognostic factor in metastatic lung sarcoma(p=0.0026). CONCLUSION: Survival was not related to sex, cell type, laterality, DFI, operative procedure, number of metastases, nor the size of the largest metastasis. DFI was related to the survival time in sarcoma group but further study is needed.