1.Influence of Changes in Mixed Venous Oxygen Tension(PvO2) by Extracorporeal Membrane Oxygenation(ECMO) on Hypoxic Pulmonary Vasoconstriction.
Duk Hwan CHOI ; Seong Deok KIM
Korean Journal of Anesthesiology 1992;25(1):1-24
Blood flow generally decreases to areas of the lung that become hypoxie, thereby reducing pulmonary shunt and preventing arterial hypoxemia. The mechanism of blood flow reduction in the hypoxic area is believed to be hypoxic pulmonary vasoconstriction(HPV). Over the years, serious attention has been given to the question of whether hypoxia of the airway(alveolar hypoxia) is the only way to elicit pulmonary vasoconstriction. the current consensus favors this traditional view. Even though the usual experiments have succeeded in proving that a large drop in alveolar PO2(PAO2) does elicit pulmonary vasoconstriction, they have not excluded the possibility that a sufficient drop in mixed venous PO(PvO2) may have the same eonsequenee. The purpose of this study is to test the hypothesis that a decrease in PvO2 may elicit hypoxic pulmonary vasoconstriction. For the selective change of PvOwe used venovenous extracorporeal circulation(VVECMO), a technique which had been tested for adequacy in hemodynamics and oxygenation in preliminary studies on 6 mongrel dogs. In eight pentobarbital-anesthetized, mechanically ventilated mongrel dogs, stepwise reductions in oxygen concentration(F1O2,) from 0.21 to 0.15 and 0.10 caused remarkable HPV. The mean pulmonary arterial pressure(MPAP) and the pulmonary vascular resistance(PVR) were increased from 17.3+/-3 mmHg and 185+/-64 dyne sec cm(-5) in normoxia(F1O2=0.21) to 30+/-6 mmHg and 401+/-257 dyne sec cm in severe hypoxia(F1O2=0.10, P(A)O2=30+/-9 mmHg), respectively ; while, in moderate hypoxia(F1OP2=0.15, P(A)O2=53+/-12 mmHg), only the MPAP increased and the increase was from 17.3+/-3 mmHg to 23+/-3 mmHg. The selective increase in PvO2without any change in P(A)O2 by extracorporeal veno-venous bypass from 37+/-6 mmHg and 22+/-4 mmHg to 54+/-8 mmHg and 45+/-5 mnHg in moderate and severe hypoxia, respectively, depressed HPV: decrease in MPAP in moderate hypoxia(MPAP=21+/-4 mmHg) and decrease in MPAP and PVR in severe hypoxia(MPAP=23+/-5 mmHg, PVR=319+/-228 dyne sec * cm(-5)). This study indicates that the mixed venous oxygen tension is an important determinant of the magnitude of hypoxic pulmonary vasoconstriction in diffuse alveolar hypoxia. Moreover, the method used in this study and the result might be useful other pulmonary pathophysiological studies and clinical situations with acute diffuse alveolar hypoxia, such as acute respiratory failure and chronic obstructive pulmonary diseases.
Animals
;
Anoxia
;
Consensus
;
Dogs
;
Hemodynamics
;
Hypoxis
;
Lung
;
Lung Diseases, Obstructive
;
Membranes*
;
Oxygen*
;
Respiratory Insufficiency
;
Vasoconstriction*
2.CT staging of real cell carcinoma:Emphasis on perinephric tumor extension.
Yun Young CHOI ; Sun Mi KIM ; Mun Hwan CHOI ; Duk Ja BANG ; Byung Hee KOH ; On Koo CHO
Journal of the Korean Radiological Society 1993;29(4):800-804
A total of 47 preoperative CT scans in patients with renal cell carcinoma were retrospectively reviewed and compared with surgical findings to assess the accuracy of CT for determining the perinephric tumor extension. CT criteria for perinephric extension were hazy ill-defined tumor margin, perirenal nodule and fascial thickening. Regardless of the tumor stage, the accuracy of CT in detecting perinephric extension was 76.6%(36/47), with a sensitivity of 88.9% (16/18) and specificity of 68.9% (20/29). The cause of understaging (n=2) was microscopic infiltration of the perinephric space. The causes of overstaging were tumor infiltration to the renal capsule (n=5), partial adhesion with the perinephric fat (n=3) and renal vein thrombosis (n=1). A smooth clear tumor margin is highly reliable sign for stage I but infiltrative findings onto renal capsule and perirenal fat could be considered stage I.
Carcinoma, Renal Cell
;
Humans
;
Renal Veins
;
Retrospective Studies
;
Sensitivity and Specificity
;
Thrombosis
;
Tomography, X-Ray Computed
3.CT staging of real cell carcinoma:Emphasis on perinephric tumor extension.
Yun Young CHOI ; Sun Mi KIM ; Mun Hwan CHOI ; Duk Ja BANG ; Byung Hee KOH ; On Koo CHO
Journal of the Korean Radiological Society 1993;29(4):800-804
A total of 47 preoperative CT scans in patients with renal cell carcinoma were retrospectively reviewed and compared with surgical findings to assess the accuracy of CT for determining the perinephric tumor extension. CT criteria for perinephric extension were hazy ill-defined tumor margin, perirenal nodule and fascial thickening. Regardless of the tumor stage, the accuracy of CT in detecting perinephric extension was 76.6%(36/47), with a sensitivity of 88.9% (16/18) and specificity of 68.9% (20/29). The cause of understaging (n=2) was microscopic infiltration of the perinephric space. The causes of overstaging were tumor infiltration to the renal capsule (n=5), partial adhesion with the perinephric fat (n=3) and renal vein thrombosis (n=1). A smooth clear tumor margin is highly reliable sign for stage I but infiltrative findings onto renal capsule and perirenal fat could be considered stage I.
Carcinoma, Renal Cell
;
Humans
;
Renal Veins
;
Retrospective Studies
;
Sensitivity and Specificity
;
Thrombosis
;
Tomography, X-Ray Computed
4.A Comparative Study of Radiographic Images on Normal Anatomical Structures.
Heang Hee CHOI ; Eui Hwan CHOI ; Jae Duk KIM
Journal of Korean Academy of Oral and Maxillofacial Radiology 1999;29(1):283-297
PURPOSE: To compare radiographic images of Digora system and Ektaspeed Plus film obtained from normal adults. MATERIALS AND METHODS: Storage phosphor plate(SPP) was placed in a film holder behind Ektaspeed Plus film package without lead foil. The effect of film on SPP was studied in a separate in vitro experiment. Forty-seven sets of images were prepared for the evaluaton. The regions of interest(ROI) for evaluation were designated at seven sites including normal anatomical structures. The image quality for each ROI was evaluated on enhanced and unenhanced storage phosphor(SP) images and Ektaspeed Plus film. RESULTS: Two film-SPP configurations showed significantly different grey levels at each step of the aluminum step wedge(p<0.05). The contrasts were comparable. Enhanced SP images were significantly superior to unenhaned images and film in all anatomical sturctures(p<0.01). The differences between unenhanced SP images and film were significant(p<0.05) except root canal and cortical bone on alveolar crest. For anatomical items, there were statistically significant difference among five observers(p<0.05). CONCLUSIONS: The image quality of enhanced SP images were superior to Ektaspeed Plus film, and Digora system is potentially applicable to clinical diagnosis.
Adult
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Aluminum
;
Dental Pulp Cavity
;
Diagnosis
;
Humans
;
Radiography, Dental, Digital
5.Usefulness of echocardiographic findings in the early diagnosis of Kawasaki disease.
Chang Hwan CHOI ; Sung Hwan BYUN ; Je Duk JEON ; Jong Woon CHOI
Korean Journal of Pediatrics 2007;50(1):47-51
PURPOSE: The early diagnosis of Kawasaki disease (KD) is difficult sometimes, especially in atypical or incomplete cases presenting 4 or less principal clinical features without coronary arterial lesions (coronary arterial ectasia or aneurysm). The authors investigated the incidence of echocardiographic abnormalities in patients with KD to discover whether abnormal echocardiographic findings might be helpful in the early diagnosis of KD. METHODS: Echocardiography was done in the acute stage of 103 patients with KD (Kawasaki group) and 40 patients with other acute febrile illnesses (control group). Abnormal echocardiographic findings were classified into 4 categories and defined as follows; 1) significant pericardial effusion, 2) significant valvular dysfunctions, 3) left ventricular systolic dysfunction, 4) coronary arterial ectasia or aneurysm. RESULTS: In the Kawasaki group, significant pericardial effusion was present in 24 patients (23.3 percent), significant valvular dysfunctions in 30 patients (29.1 percent), left ventricular systolic dysfunction in 10 patients (9.7 percent), and coronary arterial lesions in 27 patients (26.2 percent). In the control group, significant pericardial effusion was present in only one patient (2.5 percent). The number of patients with any one of echocardiographic abnormalities was 57 (55.3 percent) in Kawasaki group and one (2.5 percent) in control group. The sensitivity of echocardiography in the diagnosis of KD was 55.3 percent, the specificity 97.5 percent, the positive predictive value 98.3 percent, and the negative predictive value 45.9 percent. CONCLUSION: If abnormal echocardiographic findings, even if other than coronary arterial lesions, are confirmed in patients in whom KD is suspected, it seems desirable to inifiate specific treatment for KD.
Aneurysm
;
Diagnosis
;
Dilatation, Pathologic
;
Early Diagnosis*
;
Echocardiography*
;
Humans
;
Incidence
;
Mucocutaneous Lymph Node Syndrome*
;
Pericardial Effusion
;
Sensitivity and Specificity
6.Visibility of the mandibular canal and the mental foramen in panoramic radiography.
Seon Jin JEONG ; Eui Hwan CHOI ; Jae Duk KIM
Korean Journal of Oral and Maxillofacial Radiology 2001;31(3):153-158
PURPOSE: To determine the head position that the superior border of the mandibular canal as well as mental foramen can be more clearly visualized in panoramic radiography MATERIALS AND METHODS: Ten dry mandibles were radiographed bilaterally using PM 2002 CC panoramic machine. A 20 mm thick aluminium filter was added to the slit collimator to obtain radiographs with acceptable density. The specimens were tilted by 2, 4, 6, 8, and 10 degrees downward with and without radiopaque markers. Radiopaque markers were inserted into the mandibular canals and the mental canals of each side of the specimens to serve as reference image when assessing the radiographs. The visibility of the mandibular canal and the mental foramen was estimated by 4 observers on all radiographs. The obtained results were analyzed statistically. RESULTS: Mandibular canals were significantly more clearly visible in the radiographs with 4 and 6 degree downward position on both sides (P<0.05). Mental foramens were significantly more clearly visible in the radiographs with 4, 6, and 8 degree downward on right side and 6 degree downward on left side (P<0.05). There was not significant difference between right and left sides. CONCLUSION: Panoramic radiographs with 4 to 6 degree downward tilting could be valuable in locating the mandibular canal as well as the mental foramen.
Head
;
Mandible
;
Radiography
;
Radiography, Panoramic*
7.A Study on the Diagnostic Detection Ability of the Artificial Proximal Caries by Digora(R).
Kyung Ran OH ; Eui Hwan CHOI ; Jae Duk KIM
Journal of Korean Academy of Oral and Maxillofacial Radiology 1998;28(2):415-433
Digora system is an intraoral indirect digital radiography system utilizing storage phosphor image plate. It has wide dynamic range which allows it to decrease the patient's exposure time and may increase diagnostic ability through image processing (such as edge enhancement, grey scale conversion, brightness change, and contrast enhancement). And also, it can transmit and storage image information. The purpose of this study was to evaluate the diagnostic ability of artificial proximal caries between Conventional radiograph and Digora images(unenhanced image, brightness & contrast controlled image, and edge enhanced image). ROC(Receiver Operating Characteristic) analysis, paired t-tests, and F-tests were done for the statistical evaluation of detectability. The following results were acquired: 1. In Grade I lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.953, 0.933, 0.965, 0.978 (p>0.05). 2. In Grade II lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.969, 0.964, 0.988, 0.994. Among theses areas, there was just statistical significance between Diagnostic abilities of Digora edge enhanced image and Conventional radiograph(p<0.05). 3.In the Interobserver variability, the ROC curve areas of Digora edge enhanced image was lowerest in these areas, regardless of the Carious lesion depths. In conclusion, intraoral indirect digital system, Digora system, has the potential possibility as an alternative of Conventional radiograph in the diagnosis of proximal caries.
Dental Caries
;
Diagnosis
;
Observer Variation
;
Radiographic Image Enhancement
;
Radiography
;
Radiography, Dental, Digital
;
ROC Curve
8.Benign Papilloma Developed in Completely-healed Burn Wound.
Young Hwan CHOI ; Duk Ju MOON ; Sun Kyu KIM
Journal of Korean Burn Society 2011;14(2):143-145
A 72-year-old female with 10% TBSA flame, mostly partial thickness, was treated topically with 10% mafenide acetate cream and 1% silver sulfadiazine cream. On day 28, burn wound was nearly healed but black colored, 3~5 mm sized maculopapular lesions developed in healed facial burn wound. Similar skin lesion progressed in both hand and both wrist. All skin lesions were peeled off. On day 30, biopsy was performed. An excisional biopsy of the lesion in the left cheek revealed benign papilloma. On day 44, we excised all skin lesions and performed STSG. All graft sites were healed 14th day after STSG.
Aged
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Biopsy
;
Burns
;
Cheek
;
Female
;
Hand
;
Humans
;
Mafenide
;
Papilloma
;
Silver Sulfadiazine
;
Skin
;
Transplants
;
Wrist
9.Effects of cytokine combinations on lymphokine-activated killer(LAK) cell generation.
In Hwan SUNG ; Ji Young CHOI ; Hwan Joong YOON ; Ewi Kun JUN ; Joon Young KIL ; Duk Hyun CHO ; Sam Yong KIM ; Hong Kyoo ROH
Journal of the Korean Cancer Association 1993;25(5):751-759
No abstract available.
10.Polycystic Kidneys: Report of 2 Cases.
Duk Hwan KIM ; Il Yup CHOI ; Sang Il SONG ; Jong Han CHOI ; Jhy Bok LEE
Korean Journal of Urology 1978;19(3):247-251
Polycystic kidneys are congenital and bilateral diseases, and those symptoms almost do not appear until after age 40. Two cases of polycystic kidneys in a 53 year-old male having suffered from frequent epistaxis and a 45 year-old female having felt a generalized pain on whole body were herein reported. Its prognoses were grave.
Epistaxis
;
Female
;
Humans
;
Male
;
Middle Aged
;
Polycystic Kidney Diseases*
;
Prognosis