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Kang DS, Yang PS, Kim D, Jang E, Yu HT, Kim TH, Sung JH, Pak HN, Lee MH, Lip GYH, Joung B. Racial Differences in Ischemic and Hemorrhagic Stroke: An Ecological Epidemiological Study. Thromb Haemost 2024. [PMID: 38423097 DOI: 10.1055/a-2278-8769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
BACKGROUND This study aimed to evaluate racial differences in the incidence of stroke by conducting an ecological epidemiological study using UK Biobank and Korean nationwide data. METHODS This study used individual data from the Korean National Health Insurance Service-Health Screening and UK Biobank, which included participants who underwent health examinations between 2006 and 2010. We included 112,750 East Asians (50.7% men, mean age: 52.6 years) and 210,995 Caucasians (44.7% men, mean age: 55.0 years) who were not diagnosed with atrial fibrillation, cardiovascular diseases, chronic kidney disease, chronic obstructive pulmonary disease, or cancer. The primary outcome was defined as a composite of ischemic and hemorrhagic stroke. RESULTS East Asians tended to have a lower body mass index (23.7 vs. 26.4 kg/m2, p < 0.001) and a higher proportion of participants who did not engage in moderate-to-vigorous physical activity (49.6% vs. 10.7%, p < 0.001) than Caucasians. During the follow-up, East Asians had higher 5-year incidence rates (presented as per 1,000 person-years) for primary outcome (1.73 vs. 0.50; IR ratio [IRR]: 3.48, 95% confidence interval [CI]: 3.13-3.88), ischemic stroke (1.23 vs. 0.33; IRR: 3.70, 95% CI: 3.25-4.21), hemorrhagic stroke (0.56 vs. 0.18; IRR: 3.20, 95% CI: 2.67-3.84), and atrial fibrillation-related stroke (0.19 vs. 0.09; IRR: 2.04, 95% CI: 1.55-2.68). CONCLUSION Based on this ecological epidemiological study, racial differences in stroke incidence were robust to a variety of statistical analyses, regardless of the subtype. This suggests the need for region-specific approaches to stroke prevention.
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Affiliation(s)
- Dong-Seon Kang
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Pil-Sung Yang
- Division of Cardiology, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea
| | - Daehoon Kim
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Eunsun Jang
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hee Tae Yu
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Tae-Hoon Kim
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jung-Hoon Sung
- Division of Cardiology, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea
| | - Hui-Nam Pak
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Moon-Hyoung Lee
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University and Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Boyoung Joung
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
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Kang DS, Yang PS, Kim D, Jang E, Yu HT, Kim TH, Sung JH, Pak HN, Lee MH, Lip GYH, Joung B. Racial Differences in Bleeding Risk: An Ecological Epidemiological Study Comparing Korea and United Kingdom Subjects. Thromb Haemost 2024. [PMID: 38359877 DOI: 10.1055/a-2269-1123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
BACKGROUND This study aimed to evaluate racial differences in bleeding incidence by conducting an ecological epidemiological study using data from Korea and the United Kingdom. METHODS We included healthy participants from the Korean National Health Insurance Service-Health Screening and the UK Biobank who underwent health examinations between 2006 and 2010 and had no comorbidities or history of medication use. Finally, 112,750 East Asians (50.7% men, mean age 52.6 years) and 210,995 Caucasians (44.7% men, mean age 55.0 years) were analyzed. The primary outcome was composed of intracranial hemorrhage (ICH) and bleeding from the gastrointestinal, respiratory, and genitourinary systems. RESULTS During the follow-up, primary outcome events occurred in 2,110 East Asians and in 6,515 Caucasians. East Asians had a 38% lower 5-year incidence rate compared with Caucasians (3.88 vs. 6.29 per 1,000 person-years; incidence rate ratio [IRR]: 0.62, 95% confidence interval [CI]: 0.59-0.65). East Asians showed a lower incidence of major bleeding (IRR: 0.86, 95% CI: 0.81-0.91), bleeding from the gastrointestinal (IRR: 0.53, 95% CI: 0.49-0.56), and genitourinary systems (IRR: 0.49, 95% CI: 0.44-0.53) compared with Caucasians. The incidence rates of ICH (IRR: 3.20, 95% CI: 2.67-3.84) and bleeding from the respiratory system (IRR: 1.28, 95% CI: 1.11-1.47) were higher in East Asians. Notably, East Asians consuming alcohol ≥3 times/week showed a higher incidence of the primary outcome than Caucasians (IRR: 1.12, 95% CI: 1.01-1.25). CONCLUSION This ecological study revealed significant racial differences in bleeding incidence, influenced by anatomical sites and lifestyle habits, underscoring the need for tailored approaches in bleeding management based on race.
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Affiliation(s)
- Dong-Seon Kang
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Pil-Sung Yang
- Division of Cardiology, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea
| | - Daehoon Kim
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Eunsun Jang
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hee Tae Yu
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Tae-Hoon Kim
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jung Hoon Sung
- Division of Cardiology, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea
| | - Hui-Nam Pak
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Moon-Hyoung Lee
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital, Liverpool, United Kingdom
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Boyoung Joung
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
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Kang DS, Sung JH, Kim D, Jin MN, Jang E, Yu HT, Kim TH, Pak HN, Lee MH, Lip G, Yang PS, Joung B. Association between exercise habit changes and mortality following a cardiovascular event. Heart 2022; 108:1945-1951. [PMID: 35589378 DOI: 10.1136/heartjnl-2022-320882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/27/2022] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE To investigate the associations between exercise habit changes following an incident cardiovascular event and mortality in older adults. METHODS We analysed the relationship between exercise habit change and all-cause, cardiovascular and non-cardiovascular deaths in adults aged ≥60 years between 2003 and 2012 who underwent two consecutive health examinations within 2 years before and after diagnosis of cardiovascular disease (CVD). They were categorised into four groups according to exercise habit changes: persistent non-exercisers, exercise dropouts, new exercisers and exercise maintainers. Differences in baseline characteristics were adjusted using inverse probability of treatment weighting. RESULTS Of 6076 participants, the median age was 72 (IQR 69-76) years and men accounted for 50.6%. Compared with persistent non-exercisers (incidence rate (IR) 4.8 per 100 person-years), new exercisers (IR 3.5, HR 0.73, 95% CI 0.58 to 0.91) and exercise maintainers (IR 2.9, HR 0.53, 95% CI 0.38 to 0.73) were associated with reduced risk of all-cause death. The rate of non-cardiovascular death was significantly lower in new exercisers (IR 2.3, HR 0.73, 95% CI 0.56 to 0.95) and exercise maintainers (IR 2.3, HR 0.61, 95% CI 0.42 to 0.90) than in persistent non-exercisers (IR 3.2). Also, trends towards reduced cardiovascular death in new exercisers and exercise maintainers were observed (p value for trend <0.001). CONCLUSIONS More virtuous exercise trajectories in older adults with CVD are associated with lower mortality rates. Our results support public health recommendations for older adults with CVD to perform physical activity.
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Affiliation(s)
- Dong-Seon Kang
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Jung-Hoon Sung
- Division of Cardiology, CHA Bundang Medical Center, Seongnam, Korea
| | - Daehoon Kim
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Moo-Nyun Jin
- Division of Cardiology, Inje University College of Medicine, Busan, Korea
| | - Eunsun Jang
- Cardiology, Yonsei University College of Medicine, Seodaemun-gu, Korea
| | - Hee Tae Yu
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Tae-Hoon Kim
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Hui-Nam Pak
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Moon-Hyoung Lee
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Gregory Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool, UK
| | - Pil-Sung Yang
- Division of Cardiology, CHA Bundang Medical Center, Seongnam, Korea
| | - Boyoung Joung
- Department of Internal Medicine, Yonsei University College of Medicine, Seodaemun-gu, Korea
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Kang DS, Khmao P, Oh J, Pak HN. A Case of SCN5A Mutation-Associated Isolated Left Atrial Standstill and Ischemic Stroke. Korean Circ J 2022; 52:717-719. [PMID: 35927039 PMCID: PMC9470493 DOI: 10.4070/kcj.2022.0094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/12/2022] [Accepted: 06/08/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Dong-Seon Kang
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Korea
| | - Pichmanil Khmao
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Korea
| | - Jaewon Oh
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Korea
| | - Hui-Nam Pak
- Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Korea
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Lee JJ, Chang Y, Tirman PJ, Ryum HK, Lee SK, Kim YS, Kang DS. Optimizing of gadolinium-enhanced MR angiography by manipulation of acquisition and scan delay times. Eur Radiol 2001; 11:754-66. [PMID: 11372604 DOI: 10.1007/s003300000710] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
An optimized protocol for achieving high-quality contrast-enhanced MR angiography (CE MRA) was designed and evaluated. Time-intensity curves of the test bolus and main bolus were compared in 11 volunteers. To identify the acquisition zone sensitive to venous overprojection, sequential filling phantoms which consisted of 12 test tubes were developed and scanned. Using the parameters of the time-intensity curve which were consistent between the test and main boluses and the parameters of the sensitive acquisition zone in the pulse sequences, the protocol for calculation of scan delay time and acquisition time was optimized. The new protocol was verified by comparison of lower extremity CE MRAs acquired by traditional (scan delay time = peak enhancement time minus injection duration/2 + acquisition time/2; n = 12) and new (n = 23) protocols. The arterial and venous enhancing times of the time-intensity curves of the test and main boluses were statistically consistent (p < 0.01). The length of the sensitive acquisition zone was one-half the acquisition duration. With the parameters identified in the time-intensity curve and pulse sequence analyses, a new protocol was developed. For validation, the new protocol was able to study the smaller arteries such as the distal tibial arteries and branches of the femoral and iliac arteries (p < 0.01). Using the optimized protocol, higher-quality images were obtained than those acquired by traditional methods.
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Affiliation(s)
- J J Lee
- Department of Diagnostic Radiology, School of Medicine, Kyungpook National University, 50, 2-Ga, Samduk-Dong, Jung-Gu, Taegu, 700-412, Korea.
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Affiliation(s)
- Y H Choi
- Department of Radiology, Dankook University Hospital, Cheonan, Korea.
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Leeb-Lundberg LM, Kang DS, Lamb ME, Fathy DB. The human B1 bradykinin receptor exhibits high ligand-independent, constitutive activity. Roles of residues in the fourth intracellular and third transmembrane domains. J Biol Chem 2001; 276:8785-92. [PMID: 11134011 DOI: 10.1074/jbc.m007396200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The B1 bradykinin (BK) receptor (B1R) is a seven-transmembrane domain, G protein-coupled receptor that is induced by injury and important in inflammation and nociception. Here, we show that the human B1R exhibits a high level of ligand-independent, constitutive activity. Constitutive activity was identified by the increase in basal cellular phosphoinositide hydrolysis as a function of the density of the receptors in transiently transfected HEK293 cells. Several B1R peptide antagonists were neutral antagonists or very weakly efficacious inverse agonists. Constitutive B1R activity was further increased by alanine mutation of Asn(121) in the third transmembrane domain of the receptor (B1A(121)). This mutant resembled the agonist-preferred receptor state since it also exhibited increased agonist affinity and decreased agonist responsiveness. A dramatic loss of constitutive activity occurred when the fourth intracellular C-terminal domain (IC-IV) of the human B2 BK receptor subtype (B2R), which exhibits minimal constitutive activity, was substituted in either B1R or B1A(121) to make B1(B2ICIV) and B1(B2ICIV)A(121), respectively. Activity was partially recovered by subsequent alanine mutation of a cluster of two serines and two threonines in IC-IV of either B1(B2ICIV) or B1(B2ICIV)A(121), a cluster that is important for B2R desensitization. The ligand-independent, constitutive activity of B1R therefore depends on epitopes in both transmembrane and intracellular domains. We propose that the activity is primarily due to the lack of critical epitopes in IC-IV that regulate such activity.
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Affiliation(s)
- L M Leeb-Lundberg
- Department of Biochemistry, the University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA.
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Abstract
Although numerous studies have documented malocclusion in various ethnic groups in the United States, the prevalence of malocclusion in the Latino population is not well known. The Latino population may be the largest minority group in the United States by the year 2004. This study analyzes the occlusion of 507 Latino adolescents between the ages of 12 and 18 years. More than 93% of the subjects demonstrated some form of malocclusion. The distribution of malocclusion patterns is presented and contrasted with data published for other ethnic groups. Information about the prevalence and types of malocclusion in the Latino population should be of interest to general dental practitioners and specialists.
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Affiliation(s)
- R G Silva
- Dental Service, VA Medical Center, 4150 Clement St., San Francisco, CA 94121, USA.
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Abstract
OBJECTIVE To determine the feasibility of transcaval transjugular intrahepatic portosystemic shunt (TIPS) in patients with occluded previous TIPS. MATERIALS AND METHODS Between February 1996 and December 2000 we performed five transcaval TIPS procedures in four patients with recurrent gastric cardiac variceal bleeding. All four had occluded TIPS, which was between the hepatic and portal vein. The interval between initial TIPS placement and revisional procedures with transcaval TIPS varied between three and 31 months; one patient underwent transcaval TIPS twice, with a 31-month interval. After revision of the occluded shunt failed, direct cavoportal puncture at the retrohepatic segment of the IVC was attempted. RESULTS Transcaval TIPS placement was technically successful in all cases. In three, tractography revealed slight leakage of contrast materials into hepatic subcapsular or subdiaphragmatic pericaval space. There was no evidence of propagation of extravasated contrast materials through the retroperitoneal space or spillage into the peritoneal space. After the tract was dilated by a bare stent, no patient experienced trans-stent bleeding and no serious procedure-related complications occurred. After successful shunt creation, variceal bleeding ceased in all patients. CONCLUSION Transcaval TIPS placement is an effective and safe alternative treatment in patients with occluded previous TIPS and no hepatic veins suitable for new TIPS.
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Affiliation(s)
- C K Seong
- Department of Radiology, Kyungpook National University School of Medicine, Daegu, Korea.
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Abstract
Pseudoxanthoma elasticum (PXE) is a heritable disorder of elastic fibers characterized by yellowish, coalescing papules on the loose and wrinkled flexural area. There have been no reports of osteoma cutis associated with PXE. A 17-year-old Korean girl presented cutis laxa-like marked wrinkling on the flexural area, and a skin biopsy specimen revealed multiple foci of ossification with irregularly clumped, basophilic-stained elastic fibers in the reticular dermis and calcium deposits along the elastic fibers. Ultrasonographic evaluation showed multiple tiny osteomas diffusely scattered along the entire abdominal wall, axillae, and medial aspect of the upper arms. We report the first case of osteoma cutis coexisting with cutis laxa-like PXE.
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Affiliation(s)
- G S Choi
- Department of Dermatology, Inha University, College of Medicine, Inchon, Korea
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Yoon KH, Kim SC, Kang DS, Lee IJ. Lichen planus pemphigoides with circulating autoantibodies against 200 and 180 kDa epidermal antigens. Eur J Dermatol 2000; 10:212-4. [PMID: 10725820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
We describe a case of lichen planus pemphigoides with circulating autoantibodies against 200 and 180 kDa epidermal antigens. A 24-year-old man presented pruritic erythematous patches with occasional central blister formation on the face, neck, and trunk and erythematous hyperkeratotic patches on the elbows and feet for 10 months. Histopathological findings of the neck and plantar lesions were consistent with lichen planus. Direct immunofluorescence studies from both lesions showed a linear deposition of IgG and C3 and cytoid bodies along the basement membrane zone. Indirect immunofluorescence studies demonstrated circulating IgG antibodies deposited on the epidermal side of salt-split skin. Immunoblot analysis using epidermal extract showed that the patient's serum reacted with 180 kDa bullous pemphigoid antigen (BPAG2) and a 200 kDa antigen. The cutaneous lesions almost cleared with a low dose of prednisolone and acitretin.
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Affiliation(s)
- K H Yoon
- Department of Dermatology, Yongdong Severance Hospital, Yonsei University College of Medicine, 146-92 Dogok-dong, Kangnam-ku, Seoul 135-720, Korea
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Schoepf UJ, Helmberger T, Holzknecht N, Kang DS, Bruening RD, Aydemir S, Becker CR, Muehling O, Knez A, Haberl R, Reiser MF. Segmental and subsegmental pulmonary arteries: evaluation with electron-beam versus spiral CT. Radiology 2000; 214:433-9. [PMID: 10671591 DOI: 10.1148/radiology.214.2.r00fe10433] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To compare contrast agent-enhanced spiral and electron-beam computed tomography (CT) for the analysis of segmental and subsegmental pulmonary arteries. MATERIALS AND METHODS CT angiography of the pulmonary arteries was performed in 56 patients to rule out pulmonary embolism. Electron-beam CT was performed in 28 patients. The other 28 patients underwent spiral CT with comparable scanning protocols. The depiction of segmental and subsegmental arteries was analyzed by three independent readers. The contrast enhancement in the main pulmonary artery was measured in each patient. RESULTS Analysis was performed in 1,120 segmental and 2, 240 subsegmental arteries. One segmental (RA7, P =.010) and two subsegmental (LA7b, P =.029; RA6a+b, P =.038) arteries in paracardiac and basal segments of the lung were depicted significantly better with electron-beam CT. There was no statistically significant difference between electron-beam and spiral CT in the total number of analyzable peripheral arteries depicted. The mean contrast enhancement in the main pulmonary artery was 362 HU in electron-beam CT studies versus 248 HU in spiral CT studies. CONCLUSION Detailed visualization of peripheral pulmonary arteries is well within the scope of advanced CT techniques. Electron-beam CT has minor advantages in analyzing paracardiac arteries, probably because of reduction of motion artifacts and higher contrast enhancement. Further studies are needed to establish whether electron-beam CT allows a more confident diagnosis of emboli in these vessels.
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Affiliation(s)
- U J Schoepf
- Department of Clinical Radiology, Klinikum Grosshadern, University of Munich, Marchioninistr 15, 81377 Munich, Germany.
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Affiliation(s)
- K S Lee
- Department of Radiology, Samsung Medical Center, Seoul, Korea.
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Abstract
OBJECTIVE To determine whether the time-intensity curves acquired by test and main dose contrast injections for MR angiography are similar. MATERIALS AND METHODS In 11 patients, repeated contrast-enhanced 2D-turbo-FLASH scans with 1-sec interval were obtained. Both test and main dose time intensity curves were acquired from the abdominal aorta, and the parameters of time-intensity curves for the test and main boluses were compared. The parameters used were arterial and venous enhancement times, arterial peak enhancement time, arteriovenous circulation time, enhancement duration and enhancement expansion ratio. RESULTS Between the main and test boluses, arterial and venous enhancement times and arteriovenous circulation time showed statistically significant correlation (p < 0.01), with correlation coefficients of 0.95, 0.92 and 0.98 respectively. Although the enhancement duration was definitely greater than infusion time, reasonable measurement of the end enhancement point in the main bolus was impossible. CONCLUSION Only arterial and venous enhancement times and arteriovenous circulation time of the main bolus could be predicted from the test-bolus results. The use of these reliable parameters would lead to improvements in the scan timing method for MR angiography.
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Affiliation(s)
- J J Lee
- Department of Diagnostic Radiology, Kyungpook National University, Taegu, Korea.
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Abstract
OBJECTIVE To determine the optimal scan timing for contrast-enhanced magnetic resonance angiography and to evaluate a new timing method based on the arteriovenous circulation time. MATERIALS AND METHODS Eighty-nine contrast-enhanced magnetic resonance angiographic examinations were performed mainly in the extremities. A 1.5T scanner with a 3-D turbo-FLASH sequence was used, and during each study, two consecutive arterial phases and one venous phase were acquired. Scan delay time was calculated from the time-intensity curve by the traditional (n = 48) and/or the new (n = 41) method. This latter was based on arteriovenous circulation time rather than peak arterial enhancement time, as used in the traditional method. The numbers of first-phase images showing a properly enhanced arterial phase were compared between the two methods. RESULTS Mean scan delay time was 5.4 sec longer with the new method than with the traditional. Properly enhanced first-phase images were found in 65% of cases (31/48) using the traditional timing method, and 95% (39/41) using the new method. When cases in which there was mismatch between the target vessel and the time-intensity curve acquisition site are excluded, erroneous acquisition occurred in seven cases with the traditional method, but in none with the new method. CONCLUSION The calculation of scan delay time on the basis of arteriovenous circulation time provides better timing for arterial phase acquisition than the traditional method.
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Affiliation(s)
- J J Lee
- Department of Diagnostic Radiology, School of Medicine, Kyungpook National University, Taegu, South Korea.
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Kang DS, Chung KY. Common blue naevus with satellite lesions: possible perivascular dissemination resulting in a clinical resemblance to malignant melanoma. Br J Dermatol 1999; 141:922-5. [PMID: 10583181 DOI: 10.1046/j.1365-2133.1999.03171.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report a case of common blue naevus with polymorphous guttate and linear satellite lesions, thereby mimicking peripherally spreading malignant melanoma. Histopathologic examination showed that the naevus cells are clustered around blood vessels in the primary as well as satellite lesions, suggestive of spreading of the naevus cells along the perivascular space. Such biological behaviour resulting in a clinical manifestation of a malignant melanoma-like lesion is a rarity in common blue naevus, a benign cutaneous disorder that is devoid of a malignant potential, and has not been described before.
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Affiliation(s)
- D S Kang
- Department of Dermatology, Yonsei University College of Medicine, Seoul, Korea
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Abstract
Sclerosis is a disease process in which idiopathic hardening occurs in the skin and/or internal organs as a result of the accumulation of type I collagen, induced mainly by transforming growth factor-beta. Colchicine and D-penicillamine are widely used for its treatment. Their effects are known to be due to post-translational down-regulation of type I collagen synthesis, with colchicine also up-regulating interstitial collagenase. To determine whether or not they have any pre-translational effect on type I collagen and MMP-1, and also to observe their effects on the action of TGF-beta, cultured neonatal foreskin fibroblasts were treated with colchicine and D-penicillamine, singly and together. The amount of type I collagen and MMP-1 mRNA were quantitated by Northern blot hybridization. Colchicine suppresses the basal level of type I collagen mRNA but minimally stimulates the mRNA expression of MMP-1, whereas D-penicillamine does not have any significant effects on either. Colchicine was also able to significantly suppress the TGF-beta-induced up-regulation of type I collagen mRNA expression.
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Affiliation(s)
- K Y Chung
- Department of Dermatology, Yonsei University College of Medicine, Seoul, Korea.
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Lee SK, Suh KJ, Kim YW, Ryeom HK, Kim YS, Lee JM, Chang Y, Kim YJ, Kang DS. Septic arthritis versus transient synovitis at MR imaging: preliminary assessment with signal intensity alterations in bone marrow. Radiology 1999; 211:459-65. [PMID: 10228529 DOI: 10.1148/radiology.211.2.r99ma47459] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To find any differential magnetic resonance (MR) imaging findings between septic arthritis and transient synovitis in pediatric patients. MATERIALS AND METHODS The MR imaging findings in nine pediatric patients with septic arthritis and 14 with transient synovitis were retrospectively studied. The diagnoses were made by means of joint aspiration with bacteriologic study, arthrotomy, and clinical evaluation. MR imaging findings were analyzed with emphasis on the grade of joint effusion and alterations in signal intensity in the soft tissue and bone marrow of the affected hip joint. RESULTS Signal intensity alterations in bone marrow (i.e., low signal intensity on fat-suppressed gadolinium-enhanced T1-weighted spin-echo images and high signal intensity on fat-suppressed T2-weighted fast spin-echo images) were seen in eight of nine patients with septic arthritis. These signal intensity alterations consisted of mild juxtaarticular changes in six patients without osteomyelitis and extensive changes in the femoral head and neck in two patients with coexistent osteomyelitis. Signal intensity alterations in bone marrow were not seen in the 14 patients with transient synovitis. CONCLUSION Signal intensity alterations in the bone marrow of the affected hip joint are useful in the differentiation of septic arthritis from transient synovitis.
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Affiliation(s)
- S K Lee
- Department of Radiology, Kyungpook National University College of Medicine, Taegu, Korea
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Mannino DM, Homa DM, Pertowski CA, Ashizawa A, Nixon LL, Johnson CA, Ball LB, Jack E, Kang DS. Surveillance for asthma--United States, 1960-1995. MMWR CDC Surveill Summ 1998; 47:1-27. [PMID: 9580746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PROBLEM/CONDITION Asthma is one of the most common chronic diseases in the United States, and it has increased in importance during the preceding 20 years. Despite its importance, no comprehensive surveillance system has been established that measures asthma trends at the state or local level. REPORTING PERIOD This report summarizes and reviews national data for specific end-points: self-reported asthma prevalence (1980-1994), asthma office visits (1975-1995), asthma emergency room visits (1992-1995), asthma hospitalizations (1979-1994), and asthma deaths (1960-1995). DESCRIPTION OF SYSTEM The National Center for Health Statistics (NCHS) annually conducts the National Health Interview Survey, which asks about self-reported asthma in a subset of the sample. NCHS collects physician office visit data with the National Ambulatory Medical Care Survey, emergency room visit data with the National Hospital Ambulatory Medical Care Survey, and hospitalization data with the National Hospital Discharge Survey. NCHS also collects mortality data annually from each state and produces computerized files from these data. We used these datasets to determine self-reported asthma prevalence, asthma office visits, asthma emergency room visits, asthma hospitalizations, and asthma deaths nationwide and in four geographic regions of the United States (i.e., Northeast, Midwest, South, and West). RESULTS We found an increase in self-reported asthma prevalence rates and asthma death rates in recent years both nationally and regionally. Asthma hospitalization rates have increased in some regions and decreased in others. At the state level, only death data are available for asthma; death rates varied substantially among states within the same region. INTERPRETATION Both asthma prevalence rates and asthma death rates are increasing nationally. Available surveillance information are inadequate for fully assessing asthma trends at the state or local level. Implementation of better state and local surveillance can increase understanding of this disease and contribute to more effective treatment and prevention strategies.
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Affiliation(s)
- D M Mannino
- Division of Environmental Hazards and Health Effects
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Kang DS, Kahler LR, Tesar CM. Cultural aspects of caring for refugees. Am Fam Physician 1998; 57:1245-6, 1249-50, 1253-4, passim. [PMID: 9531909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- D S Kang
- UMDNJ-New Jersey Medical School, Newark, USA
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Jung JS, Oh SO, Kim MG, Kang DS, Lee SH. Cl- secretion induced by 5-hydroxytryptamine and calcitonin gene-related peptide in rat tracheal epithelia. Pflugers Arch 1997; 435:20-7. [PMID: 9359899 DOI: 10.1007/s004240050479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effects of 5-hydroxytryptamine (5-HT) and calcitonin gene-related peptide (CGRP), which are colocalized in nerve terminals in the airway, on Cl- secretion in rat tracheal epithelia were tested. Short-circuit current (Isc) was measured after rat tracheal epithelial monolayers were cultured on porous filters. In rat tracheal monolayers 5-HT and CGRP increased Isc upon addition to the serosal compartment, in a dose-dependent manner with EC50 values at 5 micromol/l and 5 nmol/l, respectively. The responses were dependent on the presence of Cl- in the bathing solution and were inhibited by 100 micromol/l bumetanide. When 5-HT or CGRP was added after the administration of forskolin, the responses were not observed. 5-HT and CGRP increased the intracellular cAMP concentration. Low-Ca2+ buffer (0.1 mmol/l) and pretreatment with BAPTA/AM (10 micromol/l), thapsigargin (1 micromol/l) or indomethacin (10 micromol/l) did not affect the responses to 5-HT and CGRP. The 5-HT-induced response was not inhibited by 5-HT2 and/or 5-HT4 antagonists. These results indicate that in the rat tracheal epithelia 5-HT and CGRP increase Cl- secretion by an increase in intracellular cAMP concentration via direct activation of basolateral receptors, and that the response to 5-HT is not mediated via 5-HT4 receptors.
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Affiliation(s)
- J S Jung
- Department of Physiology, College of Medicine, Pusan National University, 1 Ga, Ami-Dong, Suh-Gu, Pusan, Korea
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Abstract
We report a case of pulmonary aspergilloma which developed within intralobar pulmonary sequestration.
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Affiliation(s)
- J Y Park
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Taegu, Korea
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Abstract
Plastic bronchitis is generally associated with some type of pulmonary disease and improves either spontaneously or with medical therapy. We present a case of plastic bronchitis with no known cause. The patients' symptoms were not responsive to medical therapy but were relieved after right middle lobectomy.
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Affiliation(s)
- J Y Park
- Dept of Internal Medicine, Diagnostic Radiology, University of Pennsylvania Medical Center, Philadelphia, USA
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Vockley JG, Tabor DE, Kern RM, Goodman BK, Wissmann PB, Kang DS, Grody WW, Cederbaum SD. Identification of mutations (D128G, H141L) in the liver arginase gene of patients with hyperargininemia. Hum Mutat 1994; 4:150-4. [PMID: 7981719 DOI: 10.1002/humu.1380040210] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- J G Vockley
- Division of Medical Genetics, UCLA School of Medicine 90024
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Abstract
OBJECTIVE Hypereosinophilic syndrome (eosinophilia without demonstrable cause) commonly involves eosinophilic infiltration of the liver and spleen, but few reports have described the imaging findings. Accordingly, we reviewed the imaging findings in five patients with this syndrome in whom the liver was involved. MATERIALS AND METHODS Five patients who had hypereosinophilic syndrome with hepatic involvement were included in the study. The diagnosis of hepatic involvement was based on pathologic proof in two patients and on imaging and laboratory findings in the other three. Histologic examination of the hepatic lesions showed extensive eosinophilic infiltration in two patients and centrilobular necrosis in one. All patients had chest radiography, barium studies of the gastrointestinal tract, abdominal CT, and sonography. Four patients had hepatosplenic scintigraphy. All patients were followed up for 4-24 months. RESULTS All patients had mild to marked hepatomegaly with multiple focal lesions. Focal lesions were detected on sonograms in three patients, on CT scans in four, and on scintigrams in three. On sonograms, the lesions were usually small (less than 2 cm in diameter), sharply or poorly defined nodules with varied echogenicity scattered throughout the liver. The lesions were hypodense with poorly defined margins on CT scans and appeared as variably sized areas of decreased radionuclide uptake on scintigrams. For each patient, the number, size, and shape of the lesions varied considerably from one imaging study to another. On follow-up studies 2-6 months after treatment, the appearance of the liver was normal. Other radiologic findings included transient pulmonary infiltrates (two patients), mild cardiomegaly (one patient), and mild lymphadenopathy (three patients). CONCLUSION Hypereosinophilic syndrome is a cause of focal hepatic lesions seen on sonograms, CT scans, or scintigrams. The lesions are characterized by the varied appearance on the different types of images and the disappearance of the lesions with treatment.
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Affiliation(s)
- G B Kim
- Department of Radiology, Kyungpook National University College of Medicine, Taegu, Korea
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Abstract
cDNA coding for N-terminally truncated human annexin I, a member of the family of Ca(2+)-dependent phospholipid binding proteins, has been cloned and expressed in Escherichia coli. The expressed protein is biologically active, and has been purified and crystallized in space group P2(1)2(1)2(1) with cell dimensions a = 139.36 A, b = 67.50 A, and c = 42.11 A. The crystal structure has been determined by molecular replacement at 3.0 A resolution using the annexin V core structure as the search model. The average backbone deviation between these two structures is 2.34 A. The structure has been refined to an R-factor of 17.7% at 2.5 A resolution. Six calcium sites have been identified in the annexin I structure. Each is located in the loop region of the helix-loop-helix motif. Two of the six calcium sites in annexin I are not occupied in the annexin V structure. The superpositions of the corresponding loop regions in the four domains show that the calcium binding loops in annexin I can be divided into two classes: type II and type III. Both classes are different from the well-known EF-hand motif (type I).
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Affiliation(s)
- X Weng
- Department of Molecular and Cell Biology, University of California, Berkeley 94720
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Kim KL, Kang DS, Vitello LB, Erman JE. Cytochrome c peroxidase catalyzed oxidation of ferrocytochrome c by hydrogen peroxide: ionic strength dependence of the steady-state rate parameters. Biochemistry 1990; 29:9150-9. [PMID: 2176845 DOI: 10.1021/bi00491a008] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The steady-state kinetics of the cytochrome c peroxidase catalyzed oxidation of horse heart ferrocytochrome c by hydrogen peroxide have been studied at both pH 7.0 and pH 7.5 as a function of ionic strength. Plots of the initial velocity versus hydrogen peroxide concentration at fixed cytochrome c are hyperbolic. The limiting slope at low hydrogen peroxide give apparent bimolecular rate constants for the cytochrome c peroxidase-hydrogen peroxide reaction identical with those determined directly by stopped-flow techniques. Plots of the initial velocity versus cytochrome c concentration at saturating hydrogen peroxide (200 microM) are nonhyperbolic. The rate expression requires squared terms in cytochrome c concentration. The maximum turnover rate of the enzyme is independent of ionic strength, with values of 470 +/- 50 s-1 and 290 +/- 30 s-1 at pH 7.0 and 7.5, respectively. The limiting slope of velocity versus cytochrome c concentration plots provides a lower limit for the association rate constant between cytochrome c and the oxidized intermediates of cytochrome c peroxidase. The limiting slope varies from 10(6) M-1 s-1 at 300 mM ionic strength to 10(8) M-1 s-1 at 20 mM ionic strength and extrapolates to 5 x 10(8) M-1 s-1 at zero ionic strength. The data are discussed in terms of both a two-binding-site mechanism and a single-binding-site, multiple-pathway mechanism.
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Affiliation(s)
- K L Kim
- Department of Chemistry, Northern Illinois University, DeKalb 60115
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O'Connor TR, Kang DS, Wells RD. Thermodynamic parameters are sequence-dependent for the supercoil-induced B to Z transition in recombinant plasmids. J Biol Chem 1986; 261:13302-8. [PMID: 3759965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The entropy and enthalpy changes which contribute to the thermodynamics of the B to Z transition were determined for three recombinant plasmids containing a (dC-dG)16 tract and for a plasmid containing a pair of (dT-dG)20 regions. For each base pair which adopts a left-handed conformation in the plasmids with (dC-dG)16 sequences, the delta HBZ and delta SBZ are -2.1 kcal/mol bp and -8.8 cal/K-mol bp, respectively. In the plasmid containing the (dT-dG)20 tracts, however, the delta HBZ and delta SBZ values are 0.58 kcal/mol bp and -0.76 cal/K-mol bp, respectively. Also, these determinations show that for each B-Z junction that forms in the plasmids containing the (dC-dG), the enthalpy and entropy changes are 24 kcal/mol junction and 65 cal/K-mol junction, whereas for the (dT-dG) plasmid, the enthalpy and entropy changes are -1.8 kcal/mol junction and -22 cal/K-mol junction, respectively. Those values for the enthalpy and entropy changes for the formation of a BZ junction in (dC-dG) and (dT-dG) plasmids suggest that the properties and possibly the structures of the junctions are different. Calculations using the enthalpy and entropy changes determined in this study reveal that the B to Z transition in plasmids containing (dC-dG) blocks are more temperature-dependent than the transitions in plasmids with (dT-dG) blocks. Surprisingly, at temperatures above 60 degrees C, calculations indicate that the B to Z transitions in (dT-dG) plasmids should be energetically favored over that transition in (dC-dG) plasmids.
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O'Connor TR, Kang DS, Wells RD. Thermodynamic parameters are sequence-dependent for the supercoil-induced B to Z transition in recombinant plasmids. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)69304-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Kitchin PA, Klein VA, Ryan KA, Gann KL, Rauch CA, Kang DS, Wells RD, Englund PT. A highly bent fragment of Crithidia fasciculata kinetoplast DNA. J Biol Chem 1986; 261:11302-9. [PMID: 3015964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Kinetoplast DNA minicircles from Crithidia fasciculata contain a single major region of bent helix. Restriction fragments containing this bent helix have electrophoretic behavior on polyacrylamide gels which is much more anomalous than that of previously studied bent fragments. Therefore, the C. fasciculata fragments probably have a more extreme curvature. Sequencing part of a cloned minicircle revealed an unusual structure for the bent region. In a sequence of 200 bases, the bent region contains 18 runs of 4-6 As with 16 of these runs in the same strand. In some parts of this sequence the A runs are regularly spaced with a periodicity of about 10 base pairs. This spacing is nearly in phase with the twist of the DNA helix. This same sequence arrangement has been observed in other bent fragments, but the number of A runs is much greater in this C. fasciculata sequence. It is likely that there are small bends associated with each A run which, because of their periodic spacing, add up to produce substantial curvature in this molecule. In addition to having highly anomalous electrophoretic behavior, the fragment has unusual circular dichroism spectra. Its spectrum in the absence of ethanol is that of B DNA, but ethanol in the concentration range of 51-71% (w/w) induces changes to forms which are different from those of any well characterized DNA structure. The C. fasciculata bent helix is neither cleaved by S1 nuclease nor modified by bromoacetaldehyde under conditions in which other unusual DNA structures (such as cruciforms or B-Z junctions) are susceptible to attack by these reagents. Finally, a two-dimensional agarose gel analysis of a family of topoisomers of a plasmid containing the bent helix revealed no supercoil-induced relaxation.
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Kilpatrick MW, Torri A, Kang DS, Engler JA, Wells RD. Unusual DNA structures in the adenovirus genome. J Biol Chem 1986; 261:11350-4. [PMID: 3015967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
More than 80% (approximately 29 kilobase pairs) of the adenovirus serotype 2 genome was surveyed for the presence of unusual DNA conformations. Seven recombinant DNAs containing the largest HindIII fragments of AD2 DNA were analyzed for the presence of negative supercoil-dependent S1 nuclease-sensitive sites. Four plasmids each contained a specific site of S1 nuclease sensitivity whereas the other three showed no reaction. Further investigation was focused on a plasmid containing one of the positively reacting fragments (fragment C) which contained the major late promoter at coordinate 16.4 on the genome; three serotypes (Ad2, Ad7, Ad12) were studied. Fine mapping studies revealed the S1-sensitive sites to be a small region (approximately 6 base pairs) located at the TATA box of the major late promoter in all three cases. Other determinations (supercoil relaxation, T7 gene 3 product sensitivity, bromoacetaldehyde reactivity, anomalous gel mobility, the influence of negative superhelical density on nuclease sensitivity) led to the conclusion that the B-helix deformation was not due to a previously recognized DNA conformation (left-handed Z-DNA, cruciform, bent DNA), but may be accounted for by the homopurine X homopyrimidine nature of this region.
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Kang DS, Harvey SC, Wells RD. Diepoxybutane forms a monoadduct with B-form (dG-dC)n.(dG-dC)n and a crosslinked diadduct with the left-handed Z-form. Nucleic Acids Res 1985; 13:5645-56. [PMID: 2994006 PMCID: PMC321895 DOI: 10.1093/nar/13.15.5645] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The characteristics of the reactions of DL-diepoxybutane (DEB) with (dG-dC)n.(dG-dC)n in the right-handed B-form or the left-handed Z-form were investigated. DEB does react with right-handed B-DNA since less salt is required to convert the modified B-form to Z-form than for the unmodified DNA. However, the product appears to be a monoadduct rather than the crosslinked diadduct formed with the Z-form. The modified B-form can be isolated, converted to a Z-form with l mM MnCl2, and then this activated complex further reacts intramolecularly to give the crosslinked Z-product. This modified Z-form cannot be reverted to the B-form unless the crosslink is cleaved with periodate. Only MnCl2, and to a lesser extent ZnCl2, was effective in facilitating the intramolecular conversion of the B-DNA monoadduct to the Z-DNA diadduct; lmM MgCl2 and 4M NaCl were ineffective suggesting that somewhat different types of modified left-handed conformations were generated by the different salts. DEB also cleaves DNA under our reaction conditions thus precluding studies with supercoiled recombinant plasmids harboring segments that adopt Z-structures.
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Kang DS, Wells RD. B-Z DNA junctions contain few, if any, nonpaired bases at physiological superhelical densities. J Biol Chem 1985; 260:7783-90. [PMID: 2987269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The reactions of bromoacetaldehyde (BAA) with recombinant plasmids that contain sequences which can adopt left-handed Z structures or, at other locations, cruciforms were studied as a function of supercoil density. The sequence in pRW756 that undergoes a supercoil induced transition from a right to left-handed helix was (dC-dG)16 and regions near the replication origin of the pBR322 vector were converted from linearforms to cruciforms. The locations of the most nonpaired structural features were mapped by S1 nuclease cleavage of the "wedged open" duplexes after linearization of the DNAs. Three cruciforms in the pBR322 portions of the plasmids were specifically detected by BAA reaction at physiological supercoil densities (sigma = -0.067). However, the B-Z junctions did not react with BAA under these conditions although the junctions were present since the (dC-dG)16 was shown to be left-handed. Thus, the B-Z junctions have less single-stranded character than the pBR322 cruciforms (3-6 nonpaired bases) and may be fully paired. At much higher superhelical densities (sigma = -0.11-0.12), the B-Z junctions as well as the cruciforms react with BAA indicating a change in the nature of the junctions. Studies were also performed with pRW777 which harbors the mouse kappa immunoglobin sequence (dT-dG)32 . (dC-dA)32 that adopts a left-handed helix under appropriate conditions; the results were similar to those found with pRW756.
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Kang DS, Erman JE. The cytochrome c peroxidase-catalyzed oxidation of ferrocytochrome c by hydrogen peroxide. Steady state kinetic mechanism. J Biol Chem 1982; 257:12775-9. [PMID: 6290481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Initial velocities for the cytochrome c peroxidase-catalyzed oxidation of ferrocytochrome c by hydrogen peroxide have been measured as functions of both the ferrocytochrome c (0.27-104 microM) and hydrogen peroxide (0.25-200 microM) concentrations at 25 degrees C, 0.01 M ionic strength, and pH 7 in a cacodylate/KNO3 buffer system Eadie-Hofstee plots of the initial velocity as a function of ferrocytochrome c concentration at constant hydrogen peroxide are nonlinear. A mechanism is proposed which includes random addition of the two substrates to the enzyme and a single catalytically active cytochrome c binding site. The mechanism is consistent with prior studies on cytochrome c peroxidase and fits the steady state kinetic data well.
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