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Oseni AO, Chun JY, Morgan R, Ratnam L. Dealing with complications in interventional radiology. CVIR Endovasc 2024; 7:32. [PMID: 38512496 PMCID: PMC10957835 DOI: 10.1186/s42155-024-00442-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 02/28/2024] [Indexed: 03/23/2024] Open
Abstract
It is widely accepted that most misadventures, which lead to harm have not occurred because of a single individual but rather due to a failure of process that results in healthcare workers making mistakes. This failure of process and the pervasiveness of adverse events is just as prevalent in Interventional Radiology (IR) as it is in other specialities. The true prevalence and prevailing aetiology of complications in IR are not exactly known as there is a paucity of investigative literature into this area; especially when compared with other more established disciplines such as Surgery. Some IR procedures have a higher risk profile than others. However, published data suggests that many adverse events in IR are preventable (55-84%) and frequently involve a device related complication such as improper usage or malfunction. This article aims to discuss factors that contribute to complications in IR along with tools and strategies for dealing with them to achieve optimal patient outcomes.
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Affiliation(s)
- A O Oseni
- ST6 Interventional Radiology Fellow at St George's Hospital NHS Trust, London, UK.
| | - J-Y Chun
- Consultant Diagnostic and Interventional Radiologist at St Georges Hospital NHS Trust, London, UK
| | - R Morgan
- Consultant Diagnostic and Interventional Radiologist at St Georges Hospital NHS Trust, London, UK
| | - L Ratnam
- ST6 Interventional Radiology Fellow at St George's Hospital NHS Trust, London, UK
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Lewis L, Das R, Ratnam L, Chun JY, Mailli L, Ameli-Renani SM, Gonsalves M, Morgan R. Physician associates in interventional radiology: a new paradigm? Clin Radiol 2024; 79:47-50. [PMID: 37993302 DOI: 10.1016/j.crad.2023.10.018] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 09/27/2023] [Accepted: 10/17/2023] [Indexed: 11/24/2023]
Affiliation(s)
- L Lewis
- Radiology Department, St George's Hospital, London, UK.
| | - R Das
- Radiology Department, St George's Hospital, London, UK
| | - L Ratnam
- Radiology Department, St George's Hospital, London, UK
| | - J-Y Chun
- Radiology Department, St George's Hospital, London, UK
| | - L Mailli
- Radiology Department, St George's Hospital, London, UK
| | | | - M Gonsalves
- Radiology Department, St George's Hospital, London, UK
| | - R Morgan
- Radiology Department, St George's Hospital, London, UK
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Boscà-Ramon A, Ratnam L, Cavenagh T, Chun JY, Morgan R, Gonsalves M, Das R, Ameli-Renani S, Pavlidis V, Hawthorn B, Ntagiantas N, Mailli L. Impact of site of occlusion in proximal splenic artery embolisation for blunt splenic trauma. CVIR Endovasc 2022; 5:43. [PMID: 35986797 PMCID: PMC9391208 DOI: 10.1186/s42155-022-00315-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/29/2022] [Indexed: 11/29/2022] Open
Abstract
Background Proximal splenic artery embolisation (PSAE) can be performed in stable patients with Association for the Surgery of Trauma (AAST) grade III-V splenic injury. PSAE reduces splenic perfusion but maintains viability of the spleen and pancreas via the collateral circulation. The hypothesized ideal location is between the dorsal pancreatic artery (DPA) and great pancreatic artery (GPA). This study compares the outcomes resulting from PSAE embolisation in different locations along the splenic artery. Materials and methods Retrospective review was performed of PSAE for blunt splenic trauma (2015–2020). Embolisation locations were divided into: Type I, proximal to DPA; Type II, DPA-GPA; Type III, distal to GPA. Fifty-eight patients underwent 59 PSAE: Type I (7); Type II (27); Type III (25). Data was collected on technical and clinical success, post-embolisation pancreatitis and splenic perfusion. Statistical significance was assessed using a chi-squared test. Results Technical success was achieved in 100% of cases. Clinical success was 100% for Type I/II embolisation and 88% for Type III: one patient underwent reintervention and two had splenectomies for ongoing instability. Clinical success was significantly higher in Type II embolisation compared to Type III (p = 0.02). No episodes of pancreatitis occurred post-embolisation. Where post-procedural imaging was obtained, splenic perfusion remained 100% in Type I and II embolisation and 94% in Type III. Splenic perfusion was significantly higher in the theorized ideal Type II group compared to Type I and III combined (p = 0.01). Conclusion The results support the proposed optimal embolisation location as being between the DPA and GPA.
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Shin JY, Chun JY, Chang SC, Roh SG, Lee NH. Association between non-vascularised bone graft failure and compartment of the defect in mandibular reconstruction: a systematic review and meta-analysis. Br J Oral Maxillofac Surg 2021; 60:128-133. [PMID: 34815100 DOI: 10.1016/j.bjoms.2021.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 03/16/2021] [Indexed: 01/11/2023]
Abstract
Controversy exists regarding the influence of the graft placement site in the mandible on the success of non-vascularised bone grafts. In this study, we examine the association between the compartment of the mandibular defect and the bone graft failure rate. A systematic literature review and meta-analysis was performed using MEDLINE, Embase, and Cochrane databases. Failure rates according to the compartment of mandibular defect were extracted and analysed by meta-analysis. The Newcastle-Ottawa Scale was used to assess the quality of the studies, and publication bias was evaluated using funnel plots. The search strategy identified 27 publications. After screening, five were selected for review. Based on the result of comparison among these five, we found no significant statistical association between the bone graft failure rate and compartment of mandibular defect, although further investigation of prospective randomised cohort studies is required.
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Affiliation(s)
- J Y Shin
- Department of Plastic and Reconstructive Surgery, Medical School of Jeonbuk National University, Jeonju, Republic of Korea; Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea.
| | - J Y Chun
- Department of Plastic and Reconstructive Surgery, Medical School of Jeonbuk National University, Jeonju, Republic of Korea; Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea.
| | - S C Chang
- Department of Plastic and Reconstructive Surgery, Medical School of Jeonbuk National University, Jeonju, Republic of Korea; Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea
| | - S-G Roh
- Department of Plastic and Reconstructive Surgery, Medical School of Jeonbuk National University, Jeonju, Republic of Korea; Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea
| | - N-H Lee
- Department of Plastic and Reconstructive Surgery, Medical School of Jeonbuk National University, Jeonju, Republic of Korea; Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea
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Lee MK, Moon C, Lee MJ, Kwak YG, Lee E, Jeon JH, Park WB, Jung Y, Kim ES, Lee JH, Chun JY, Park SW. Risk factors for the delayed diagnosis of extrapulmonary TB. Int J Tuberc Lung Dis 2021; 25:191-198. [PMID: 33688807 DOI: 10.5588/ijtld.20.0788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND: Extrapulmonary TB (EPTB) is more difficult to diagnose than pulmonary TB. The delayed management of EPTB can lead to complications and increase the socio-economic burden.METHODS: Patients newly diagnosed with EPTB were retrospectively enrolled from 11 general hospitals in South Korea from January 2017 to December 2018. The basic characteristics of patients were described. Univariable and multivariable analyses were performed between early and delayed diagnosis groups to identify risk factors for delayed diagnosis and treatment in EPTB.RESULTS: In total, 594 patients were enrolled. Lymph node TB (28.3%) was the predominant form, followed by abdominal (18.4%) and disseminated TB (14.5%). Concurrent lung involvement was 17.8%. The positivity of diagnostic tests showed no significant difference between the two groups. Acute clinical manifestations in disseminated, pericardial and meningeal TB, and immunosuppression were associated with early diagnosis. Delayed diagnosis was associated with outpatient clinic visits, delayed sample acquisition and diagnostic departments other than infection or pulmonology.CONCLUSION: The delay in diagnosis and treatment of EPTB was not related to differences in microbiological characteristics of Mycobacterium tuberculosis itself; rather, it was due to the indolent clinical manifestations that cause referral to non-TB-specialised departments in the outpatient clinic and delay the suspicion of TB and diagnostic testing.
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Affiliation(s)
- M K Lee
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul
| | - C Moon
- Department of Internal Medicine, Inje University Busan Paik Hospital, Busan
| | - M J Lee
- Department of Internal Medicine, Inje University Sanggye Paik Hospital, Seoul
| | - Y G Kwak
- Department of Internal Medicine, Inje University Ilsan Paik Hospital, Goyang
| | - E Lee
- Department of Internal Medicine, SoonChunHyang University Seoul Hospital, Seoul, Department of Internal Medicine, Boramae Medical Center, Seoul
| | - J H Jeon
- Department of Internal Medicine, Veterans Health Service Medical Center, Seoul, Department of Internal Medicine, National Medical Center, Seoul
| | - W B Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul
| | - Y Jung
- Department of Internal Medicine, Hallym University Sacred Heart Hospital, Anyang
| | - E S Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam
| | - J H Lee
- Department of Internal Medicine, Wonkwang University College of Medicine, Iksan
| | - J Y Chun
- Department of Internal Medicine, National Cancer Center Hospital, Goyang, South Korea
| | - S W Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Department of Internal Medicine, Boramae Medical Center, Seoul
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Kim JH, Kim I, Kang CK, Jun KI, Yoo SH, Chun JY, Jung J, Kim YJ, Kim DY, Jo HB, Kim DY, Koh Y, Shin DY, Hong J, Kim NJ, Yoon SS, Kim TS, Park WB, Oh MD. Enhanced antimicrobial stewardship based on rapid phenotypic antimicrobial susceptibility testing for bacteraemia in patients with haematological malignancies: a randomized controlled trial. Clin Microbiol Infect 2020; 27:69-75. [PMID: 32272171 DOI: 10.1016/j.cmi.2020.03.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVES Recently, rapid phenotypic antimicrobial susceptibility testing (AST) based on microscopic imaging analysis has been developed. The aim of this study was to determine whether implementation of antimicrobial stewardship programmes (ASP) based on rapid phenotypic AST can increase the proportion of patients with haematological malignancies who receive optimal targeted antibiotics during early periods of bacteraemia. METHODS This randomized controlled trial enrolled patients with haematological malignancies and at least one positive blood culture. Patients were randomly assigned 1:1 to conventional (n = 60) or rapid phenotypic (n = 56) AST. The primary outcome was the proportion of patients receiving optimal targeted antibiotics 72 hr after blood collection for culture. RESULTS The percentage receiving optimal targeted antibiotics at 72 hr was significantly higher in the rapid phenotypic AST group (45/56, 80.4%) than in conventional AST group (34/60, 56.7%) (relative risk (RR) 1.42, 95% confidence interval (CI) 1.09-1.83). The percentage receiving unnecessary broad-spectrum antibiotics at 72 hr was significantly lower (7/26, 12.5% vs 18/60, 30.0%; RR 0.42, 95% CI 0.19-0.92) and the mean time to optimal targeted antibiotic treatment was significantly shorter (38.1, standard deviation (SD) 38.2 vs 72.8, SD 93.0 hr; p < 0.001) in the rapid phenotypic AST group. The mean time from blood collection to the AST result was significantly shorter in the rapid phenotypic AST group (48.3, SD 17.6 vs 83.1, SD 22.2 hr). DISCUSSION ASP based on rapid phenotypic AST can rapidly optimize antibiotic treatment for bacteraemia in patients with haematological malignancy. Rapid phenotypic AST can improve antimicrobial stewardship in immunocompromised patients.
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Affiliation(s)
- J-H Kim
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - I Kim
- Division of Haematology-Oncology, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - C K Kang
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - K-I Jun
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - S H Yoo
- Division of Haematology-Oncology, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - J Y Chun
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - J Jung
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - Y J Kim
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - D Y Kim
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - H B Jo
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - D Y Kim
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - Y Koh
- Division of Haematology-Oncology, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - D-Y Shin
- Division of Haematology-Oncology, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - J Hong
- Division of Haematology-Oncology, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - N J Kim
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - S-S Yoon
- Division of Haematology-Oncology, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
| | - T S Kim
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | - W B Park
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea.
| | - M-D Oh
- Division of Infectious Diseases, Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea
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Kim YG, Chun JY, Ha JE, Lew YO, Jo HH, Kim JH, Kim MR. A Case of XO/XX Mosaicism in the Rokitansky-Kuster-Hauser Syndrome. Who Underwent Laparoscopic Peritoneal Vaginoplasty. J Minim Invasive Gynecol 2011. [DOI: 10.1016/j.jmig.2011.08.333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Chun JY, Markose G, Bolia A. Developments in subintimal angioplasty in the infrainguinal segment. J Cardiovasc Surg (Torino) 2010; 51:213-221. [PMID: 20354491] [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: 05/29/2023]
Abstract
Since it was first described in 1990, subintimal angioplasty (SIA) has become an established percutaneous procedure for the treatment of symptomatic lower limb arterial occlusions. The concept of this technique is to create a dissection in the subintimal plane in order to cross an occluded intraluminal segment, then to re-enter the true lumen of the patent distal artery. Balloon dilatation of this subintimal channel results in a new extraluminal lumen that is free of atheromatous plaque. It is a safe and effective procedure with advantages over intraluminal angioplasty and open surgery, thereby increasing the scope of endovascular therapy to include complex infrapopliteal occlusions and high-risk patients with limb-threatening ischaemia who are unsuitable for surgical revascularization. It has good primary success rates, long-term outcomes and does not compromise future surgical revascularization, resulting in a paradigm shift in the management of lower limb ischemia with many centres adopting SIA as first-line therapy. This article aims to review the indications of SIA, variations and developments in the technique, outcomes and factors affecting patency, and complications associated with the procedure.
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Affiliation(s)
- J-Y Chun
- Department of Radiology, St. George's Hospital, London, UK
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Oh HS, Son O, Chun JY, Stacey G, Lee MS, Min KH, Song ES, Cheon CI. The Bradyrhizobium japonicum hsfA gene exhibits a unique developmental expression pattern in cowpea nodules. Mol Plant Microbe Interact 2001; 14:1286-1292. [PMID: 11763126 DOI: 10.1094/mpmi.2001.14.11.1286] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The Bradyrhizobium japonicum host-specific fixation gene hsfA was identified as essential for nitrogen fixation on cowpea, but not required for nitrogen fixation on soybean or siratro. The DNA sequence of the hsfA promoter contains a consensus RpoN, -24/-12 binding site, suggesting the involvement of a regulatory protein that binds to an upstream activating sequence (UAS). To further explore the regulation of this interesting gene, serial deletions of the hsfA promoter were made and fused with the beta-glucuronidase (GUS) gene. The HsfA3 deletion, containing 60 bp 5' of the -24/-12 sequence, showed a similar level of GUS expression to that shown by the longest fusion construct (HsfA1), containing 464 bp of upstream sequence. In contrast, the HsfA4-GUS fusion, containing only 20 bp 5' of the -24/-12 region, showed no GUS activity, delimiting the location of a putative UAS to a 40-bp region. During nodule development, GUS expression first appeared in nodules 12 days postinoculation (dpi) and reached a maximum level of expression in approximately 17-day-old nodules. By 28 dpi, HsfA-GUS expression had returned to a low, basal level. These data were consistent with the detection of hsfA mRNA by in situ hybridization in 17-day-old nodules, but not in 28-day-old nodules. In contrast to the stage-specific expression in cowpea, HsfA-GUS expression increased with nodule development in HsfA3-inoculated soybean. These data indicate that HsfA expression is regulated in cowpea in a unique developmental manner and that the DNA regulatory regions that control this expression are confined to a short, promoter-proximal region.
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Affiliation(s)
- H S Oh
- Department of Biological Science, Sookmyung Women's University, Seoul, Korea
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Koh JT, Choi HH, Ahn KY, Kim JU, Kim JH, Chun JY, Baik YH, Kim KK. Cardiac Characteristics of Transgenic Mice Overexpressing Refsum Disease Gene-Associated Protein within the Heart. Biochem Biophys Res Commun 2001; 286:1107-16. [PMID: 11527414 DOI: 10.1006/bbrc.2001.5510] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [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: 11/22/2022]
Abstract
Arrhythmia is a common cardiac symptom of Refsum disease. Recently, we identified a novel neuron-specific PAHX-associated protein (PAHX-AP1), which binds to the Refsum disease gene (PAHX). In this report, we developed heart-targeted transgenic (TG) mice under the control of alpha-myosin heavy chain promoter to determine whether cardiac overexpression of PAHX-AP1 provokes cardiac involvement symptoms. Northern and in situ hybridization analyses revealed PAHX-AP1 transcript was overexpressed in TG atrium, especially in the sinoatrial node. TG mice showed tachycardia, and tachyarrhythmia was observed in 20% of TG mice. Isolated TG atria showed higher frequency beating and were more sensitive to aconitine-induced tachyarrhythmia than the wild-type, and 40% of the TG atria showed irregular beating. Action potential duration in TG atrial fiber was shortened much more than the wild-type. Systemic administration of arrhythmogenic agents induced arrhythmia in TG mice, while no arrhythmia with the same dose in nonTG mice. Our results indicate that the chronic atrial tachycardia by overexpressed neuron-specific PAHX-AP1 transgene in atrium may be responsible for the increased susceptibility to arrhythmia.
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Affiliation(s)
- J T Koh
- Dental Science Research Institute, Chonnam National University, Kwangju, 501-190, South Korea
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Abstract
We have isolated the Arabidopsis thaliana homeobox gene Athb-12, determined its structure and activation domain, demonstrated that its promoter is inducible in response to abscisic acid (ABA) treatment, and characterized the cellular distribution of its transcripts. The single intron of the gene interrupted the leucine-zipper domain region. The 5' regulatory region of Athb-12 can drive beta-glucuronidase (GUS) expression in tobacco transgenic plants. Athb-12 gene expression was further examined using in situ hybridization to determine the cellular distribution of Athb-12 transcripts during ABA induction. A complex pattern of Athb-12 expression was observed, often associated with regions of developing vascular tissues. Analysis of chimeras constructed from Athb-12 and the DNA-binding domain of the Saccharomyces cerevisiae transcription factor GAL4 revealed that the activation domain of Athb-12 lies in the C-terminal region (amino acids 180 to 235). Taken together, our data suggest that Athb-12 is a transcriptional activator important in regulating certain developmental processes as well as in the plant's response to water stress involving ABA-mediated gene expression.
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Affiliation(s)
- Y H Lee
- Kumho Life and Environmental Science Laboratory, 572 Sangam-Dong, Kwangju, Kwangsan-Gu, 500-712, Korea
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12
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Chun JY, Smith W, Halbach VV, Higashida RT, Wilson CB, Lawton MT. Current multimodality management of infectious intracranial aneurysms. Neurosurgery 2001; 48:1203-13; discussion 1213-4. [PMID: 11383721 DOI: 10.1097/00006123-200106000-00001] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [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: 10/26/2022] Open
Abstract
OBJECTIVE To implement an algorithm for and assess multimodality (medical, endovascular, and microsurgical) treatment of patients with infectious intracranial aneurysms. METHODS Twenty patients with 27 infectious aneurysms were treated during a 10-year period. Bacterial endocarditis was the most common cause (65%). Most aneurysms presented with rupture (75%), and the middle cerebral artery was the most common location (70%). RESULTS Five patients were treated endovascularly, with direct coiling for three patients and parent artery occlusion for two patients. Ten patients (15 aneurysms) were treated surgically, with 6 aneurysms being trapped/resected, 2 trapped/bypassed, 4 clipped, and 3 wrapped. Five patients were treated medically. Treatment-associated neurological morbidity was observed for two patients (10%), and two patients died (10%). Good outcomes were observed for 16 patients (80%). CONCLUSION Factors that guide management decisions for these patients include aneurysm rupture, hematomas with increased intracranial pressure, and the eloquence of brain tissue supplied by the parent artery. Patients with unruptured infectious aneurysms are initially treated medically, with antibiotics and serial angiography. Patients with ruptured aneurysms that are not associated with hematomas and that do not involve eloquent vascular territory are treated endovascularly. Patients with ruptured aneurysms are treated surgically when there is a hematoma or the risk of ischemic complications in eloquent territory. Therefore, endovascular therapy is the first option for patients in stable condition with ruptured aneurysms; surgical therapy is the first option for patients in unstable condition with ruptured aneurysms and the second option for patients in stable condition who experience failure of endovascular therapy. Medically treated patients with enlarging or dynamic unruptured aneurysms also require direct surgical or endovascular intervention. Favorable patient outcomes can be achieved with this multimodality management.
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Affiliation(s)
- J Y Chun
- Department of Neurological Surgery, University of California, San Francisco 94143-0112, USA
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13
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Abstract
We isolated multiple cDNA clones encoding various isoforms of a mouse ribosome receptor protein (mRRp). The cDNAs were isolated from a 13.5-day-old mouse conceptus cDNA library by polymerase chain reaction-based screening. The predicted proteins encoded by these cDNAs showed significant homology with ribosome receptors present in dogs (83%), humans (80%), and chickens (45%). The cDNA isoforms had highly identical N- and C-terminal sequences but differed in their central sequences, suggesting that these cDNA isoforms may be derived by alternative splicing from a single gene. Genomic Southern blot analysis confirmed the existence of only a single mouse ribosome receptor gene. Alignments of the deduced amino acid sequences of the mRRp cDNA isoforms revealed that they differ in the number of decapeptide repeats present in the central domain of the protein. These repeats have been previously suggested to mediate ribosome binding and thus differences in repeat number may translate to different ribosome binding abilities. The longest mRRp isoform had 61 tandem repeats. This is of interest because in the human and canine ribosome receptor proteins there are only 54 tandem repeats, suggesting that humans and dogs may also have larger ribosome receptor protein isoforms. Surprisingly, mRRp has a very short basic C-terminal sequence of only 35 amino acids, while in contrast, the known human and canine forms of this protein have acidic C-terminal regions comprised of 803 and 798 amino acid residues, respectively. Although the function of the C-terminal region is currently unknown, it may be that those C-terminal sequences that are present in human and canine RRp proteins but missing in mRRp do not play critical roles in RRp function. The cDNA of the ES/130 isoform, which lacks tandem repeats and presumably are unable to bind ribosomes, could be isolated by reverse transcriptase-PCR from E 13.5 mouse embryos. mRRp mRNAs were expressed in all tissues examined but expression levels of each isoform differed between tissues. The identification of multiple mRRp isoforms in the mouse will allow us to study the regulation and function of ribosome receptors on a genetic level.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Cell Line
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Female
- Fetus
- Gene Expression
- Male
- Mice
- Molecular Sequence Data
- Protein Isoforms/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Repetitive Sequences, Amino Acid
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Tandem Repeat Sequences
- Tissue Distribution
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Affiliation(s)
- Y J Kim
- Department of Biological Science, Ewha Woman's University, 11-1 Daehyun-Dong, Seodaemoon-Gu, 120-750, Seoul, South Korea
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Abstract
We explored to determine if iNOS could be induced by insulin in osteoblast-like UMR-106 cells. Insulin (100 nM) stimulated nitric oxide production by twofold and significantly increased iNOS mRNA and protein levels. Insulin also increased collagen synthesis, but had little effect on alkaline phosphatase activity. In contrast, IGF-1 had little effect on NO production below 10 nM and it stimulated NO production by only 57% at 100 nM. IGF-1 had little effect on collagen levels, whereas it inhibited alkaline phosphatase activities in a dose-dependent manner. When an MEK inhibitor was preincubated, insulin failed to stimulate NO production, whereas insulin dramatically increased NO production in the ERK1 overexpressed cells. Taken together, it is proposed that insulin increases iNOS mRNA, iNOS protein, and NO production, possibly via activation of ERK. These may play an important role in osteoblast functions such as collagen synthesis.
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Affiliation(s)
- S J Kim
- Department of Pharmacology, Kyung-Hee University, Seoul, 130-701, Korea.
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Kwon JH, Chun JY, Lee HS, Cheon CI, Song ES, Min KH, Lee MS. Cloning of the histidine biosynthetic genes from Corynebacterium glutamicum: organization and analysis of the hisG and hisE genes. Can J Microbiol 2000; 46:848-55. [PMID: 11006846] [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: 02/17/2023]
Abstract
The physically linked hisG and hisE genes, encoding for ATP-phosphoribosyltransferase and phosphoribosyl-ATP-pyrophosphohydrolase were isolated from the Corynebacterium glutamicum gene library by complementation of Escherichia coli histidine auxotrophs. They are two of the nine genes that participate in the histidine biosynthetic pathway. Molecular genetics and sequencing analysis of the cloned 9-kb insert DNA showed that it carries the hisG and hisE genes. In combining this result with our previous report, we propose that all histidine biosynthetic genes are separated on the genome by three unlinked loci. The coding regions of the hisG and hisE genes are 279 and 87 amino acids in length with a predicted size of about 30 and 10 kDa, respectively. Computer analysis revealed that the amino acid sequences of the hisG and hisE gene products were similar to those of other bacteria.
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Affiliation(s)
- J H Kwon
- Department of Biological Science, Sookmyung Women's University, Seoul, Korea
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16
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Hwang IT, Lee YH, Moon BC, Ahn KY, Lee SW, Chun JY. Identification and characterization of a new member of the placental prolactin-like protein-C (PLP-C) subfamily, PLP-Cbeta. Endocrinology 2000; 141:3343-52. [PMID: 10965907 DOI: 10.1210/endo.141.9.7635] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have isolated a complementary DNA (cDNA) clone that encodes a new member of the PRL-like protein-C (PLP-C) subfamily of the PRL gene family. The clone was amplified from a 13.5-day-old mouse conceptus cDNA library by PCR using primers based on conserved regions of PLP-C sequences. The full-length cDNA encodes a predicted protein of 241 residues, which contains a putative signal sequence and 2 putative N-linked glycosylation sites. The predicted protein shares 55-66% amino acid identity with mouse PLP-Calpha and rat PLP-D, PLP-H, PLP-Cv, and PLP-C and also contains 6 homologously positioned cysteine residues. Thus, we named this protein PLP-Cbeta for consistency. We have also isolated rat PLP-Cbeta from rat placenta cDNA library. Surprisingly, two messenger RNA (mRNA) isoforms of rat PLP-Cbeta were isolated: one mRNA (rPLP-Cbeta) encodes a 241-amino acid product, but another mRNA (rPLP-Cbetadelta39) lacks 39 bases that encode for a region rich in aromatic amino acids. The 39-bp region corresponds to exon 3 of other PLP-C subfamily members, such as PLP-Calpha, PLP-Cv, and d/tPRP. It suggests that the two isoforms are probably generated by an alternative splicing from a single gene. RT-PCR analysis revealed that the rPLP-Cbeta form was dominantly expressed in placenta, although both isoforms are coexpressed during placentation. The mouse PLP-Cbeta mRNA expression, which was specific to the placenta, was first detected by Northern analysis on embryonic day 11.5 (E 11.5) and persisted until birth. However, in situ hybridization analysis revealed mPLP-Cbeta expression on E 10.5 in specific trophoblast subsets, such as giant cells and spongiotrophoblast cells. mPLP-Cbeta mRNA was detected in the labyrinthine zone on E 18.5, suggesting that spongiotrophoblast cells had penetrated the labyrinthotrophoblast zone. Consistent with the observed expression in trophoblast giant cells, PLP-Cbeta expression was also detected in in vitro differentiated Rcho-1 cells, which express the trophoblast giant cell phenotype. In summary, overall high amino acid identity (79%), the locations of cysteine residues, and consensus sites for N-linked glycosylation between mouse and rat PLP-Cbeta clearly indicate that PLP-Cbeta is a bona fide member of the PLP-C subfamily. The conservation between mouse and rat, the presence of alternative isoforms, and the pattern of expression during gestation suggest the biological significance of PLP-Cbeta during pregnancy.
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Affiliation(s)
- I T Hwang
- Kumho Life and Environmental Science Laboratory, Kwangju, Korea
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17
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Abstract
Psx (now designated as Psx-1) is a murine placenta-specific homeobox gene. Here, we report the isolation and characterization of a second mouse Psx gene (Psx-2). Although 29bp were absent towards the 3' end of Psx-2, Psx-2 and Psx-1 cDNA had identical 5' and 3' ends. Overall sequence identity between the two cDNAs was 91% at the nucleotide level and 81% at the amino acid level. Both Psx proteins contain 227 amino acids. These results suggest that they arose through a recent gene duplication. A surprising finding is that the 81% sequence identity between Psx-1 and Psx-2 proteins drops at the level of homeodomain to 78%. Further, the amino acid at position 51, which is invariably an asparagine in other homeodomains and is known to contact DNA directly, is a methionine in the homeodomains of both Psx-1 and Psx-2. This suggests that Psx proteins may interact with DNA sequences differently to those bound by other homeodomains. Southern blot analysis indicated that the two Psx genes occur on separate loci in the mouse genome. The Psx-2 gene spans approx. 2. 6kb of mouse genome, and contains four exons and three introns.
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Affiliation(s)
- Y J Han
- Kumho Life and Environmental Science Laboratory, 572 Sangam-Dong, Kwangsan-Gu, Kwangju, South Korea
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Oh HS, Chun JY, Lee MS, Min KH, Lee SH, Cheon CI. Role of hsfA gene on host-specificity by Bradyrhizobium japonicum in a broad range of tropical legumes. Can J Microbiol 2000; 46:81-4. [PMID: 10696474] [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
Bradyrhizobium japonicum mutant strain NAD163, containing a 30-kb deletion mutant encompassing the hsfA gene, was inoculated onto a broad range of legume species to test host-specificity. Most legume species formed ineffective nodules except Vigna angularis var. Chibopat and Glycine max var. Pureunkong. A hsfA insertion mutant, BjjC211, gave similar results to strain NAD163, implying that many legume species require HsfA for host-specific nitrogen fixation. To determine whether other genes in the deleted region of NAD163 are also necessary, the hsfA gene was conjugally transferred into the NAD163 mutant. The transconjugant formed effective nodules on the host legume plants, which earlier had formed ineffective nodules with mutant NAD163. Thus, we conclude that the hsfA gene in the 30-kb region is the only factor responsible for host-specific nitrogen fixation in legume plants.
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Affiliation(s)
- H S Oh
- Department of Life Science, Sookmyung Women's University, Seoul, Korea
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19
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Abstract
We previously isolated a cDNA clone for a homeobox-containing gene with its expression restricted to the extraembryonic tissues. In this study, Psx gene expression was further examined using in situ hybridization to determine the cellular distribution of Psx transcripts during embryo development. Psx expression was first detected at embryonic day 8.5 only in trophoblast giant cells and chorionic ectoderm. At E 9.5 and E 13.5, the expression was restricted to the giant cells and the labyrinthine trophoblast layer. In addition, the gene expression was detected in differentiated Rcho-1 trophoblast cells in vitro, which is typical of trophoblast giant cells in vivo, but not in proliferating Rcho-1 cells and HRP-1 cells. Interestingly, rat Psx homologue mRNA is about 200 bp shorter than mouse Psx, suggesting that there is a high degree of sequence divergence between the mouse and rat Psx homologues. The sequence divergence, perhaps as a result of rapid evolution, is further supported by the zoo blot analysis because the Psx gene was detectable only in mouse and rat but not in other vertebrate species tested. Psx is localized to the murine X chromosome. Taken together, our results suggest that Psx gene plays a unique role in the function of differentiated trophoblast cells and also serves as a useful model for studying trophoblast cell lineages and the rapid evolution of homeobox genes.
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Affiliation(s)
- J Y Chun
- Kumho Life and Environmental Science Laboratory, Kwangju, Korea.
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Chun JY, Lee MS. Cloning of the argF gene encoding the ornithine carbamoyltransferase from Corynebacterium glutamicum. Mol Cells 1999; 9:333-7. [PMID: 10420995] [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: 02/13/2023] Open
Abstract
The argF gene encoding ornithine carbamoyl-transferase (OTCase; EC2.1.3.3) has been cloned from Corynebacterium glutamicum by transforming the Escherichia coli arginine auxotroph with the genomic DNA library. The cloned DNA also complements the E. coli argG mutant, suggesting a clustered organization of the genes in the genome. We have determined the DNA sequence of the minimal fragment complementing the E. coli argF mutant. The coding region of the cloned gene is 957 nucleotides long with a deduced molecular mass of about 35 kDa polypeptide. The enzyme activity and size of the expressed protein in the E. coli auxotroph carrying the argF gene revealed that the cloned gene indeed codes for OTCase. Analysis of the amino acid sequence of the predicted protein revealed a strong similarity to the corresponding protein of other bacteria.
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Affiliation(s)
- J Y Chun
- Department of Biological Science, Sookmyung Women's University, Seoul, Korea
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Chun JY, Lee EJ, Lee HS, Cheon CI, Min KH, Lee MS. Molecular cloning and analysis of the argC gene from Corynebacterium glutamicum. Biochem Mol Biol Int 1998; 46:437-47. [PMID: 9818083 DOI: 10.1080/15216549800203962] [Citation(s) in RCA: 3] [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] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The argC gene encoding N-acetylglutamate 5-semialdehyde dehydrogenase has been cloned from Corynebacterium glutamicum by transforming Escherichia coli arginine auxotroph with the genomic DNA library. Based on the restriction map of the cloned DNA, we have subcloned and sequenced the minimal DNA fragment complementing the E. coli argC mutant. The coding region of the cloned gene is 1041 nucleotides long with a predicted molecular mass of about 38 kDa polypeptide. Enzyme activity and size of the expressed protein in the E. coli auxotroph carrying the recombinant argC gene revealed that the cloned gene indeed codes for N-acetylglutamate 5-semialdehyde dehydrogenase. Computer analysis of the amino acid sequences of the predicted protein revealed a strong similarity to the corresponding protein of other bacteria.
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Affiliation(s)
- J Y Chun
- Department of Biology, Sookmyung Women's University Seoul, Korea
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Lee YH, Chun JY. A new homeodomain-leucine zipper gene from Arabidopsis thaliana induced by water stress and abscisic acid treatment. Plant Mol Biol 1998; 37:377-84. [PMID: 9617808 DOI: 10.1023/a:1006084305012] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We report the isolation and characterization of a new homeobox gene from Arabidopsis thaliana using a polymerase chain reaction (PCR) cloning strategy. The full-length cDNA, designated Athb-12, encodes a protein of 235 amino acids. It contains the conserved DNA binding domain and the leucine zipper motif, characteristic of the homeodomain-leucine zipper family of transcription factors. The deduced amino acid sequence of Athb-12 shows over 80% identity to the Arabidopsis Athb-7 in the homeodomain (82%) and the leucine zipper motif (80%) of the proteins. However, outside the homeodomain and the leucine zipper motif, the homology is significantly lower. RNA analysis identified only one 0.96 kb transcript consistent with the size of Athb-12 cDNA. The Athb-12 transcript was detected in stem, leaf, flower and root as well as in seedlings. Treatment with water stress and exogenous abscisic acid (ABA) resulted in the accumulation of Athb-12 mRNA, similar to that of Athb-7. However, the time course of the Athb-12 response to ABA differed from that of Athb-7, suggesting that both genes, in response to ABA, are regulated in different manners. Taken together, these data suggest that Athb-12 and Athb-7 are members of a related gene family involved in the plant's response to water stress.
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Affiliation(s)
- Y H Lee
- Kumho Life and Environmental Science Laboratory, Kwangju-City, Korea
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23
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Abstract
To identify homeobox genes involved in mouse embryo development, we have screened a mouse cDNA library prepared from the 13.5-day-old entire conceptus for homeobox-containing sequences using a polymerase chain reaction (PCR) cloning strategy. We identified a mouse homeobox gene that might be the prototype of a new class. The full-length cDNA, designated Psx (placenta specific-homeobox), encodes a protein of 247 amino acids. The expression patterns of the Psx during embryonic development and in adult tissues were studied by Northern blot analysis. The Psx transcript was first detected at embryonic day 8.5 of conceptus and persisted until birth. Psx mRNA is expressed in extraembryonic tissues, mainly in placenta, but not in fetus, pups and adult tissues tested, suggesting that Psx plays an important role in placenta. Psx is a new member of the murine homeobox genes which are expressed in extraembryonic tissues such as placenta and amnion.
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Affiliation(s)
- Y J Han
- Kumho Life and Environmental Science Laboratory, Kwangju-City, South Korea
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Abstract
Cowden's disease, or multiple hamartoma syndrome, is an uncommon condition with characteristic mucocutaneous lesions associated with abnormalities of the breast, thyroid, and gastrointestinal tract. We describe a 32-year-old man with oral mucosal papillomatosis and plantar hyperkeratosis as a definite case of Cowden's disease according to the criteria proposed by Salem and Steck. The patient also had a thyroid mass and numerous gastrointestinal polyps endoscopically. Histologically the polyps were hamartomatous or hyperplastic polyps. The oral papillary lesions were fibroepithelial polyps and the thyroid mass was a follicular adenoma. We review the literature on this entity and summarize the pertinent findings. To the best of our knowledge, this is the first documented case of Cowden's disease in a Korean.
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Affiliation(s)
- H R Lee
- Department of Family Medicine, Yonsei University College of Medicine, Seoul, Korea
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25
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Abstract
To study the molecular basis of tissue-specific and hormonally regulated expression of the fatty acid synthase (FAS) gene in vivo, we generated lines of transgenic mice carrying 2.1 kilobases of the 5'-flanking region (-2100 to +67) of the rat FAS gene fused to a chloramphenicol acetyltransferase (CAT) reporter gene. This reporter gene construct was strongly expressed in tissues that normally express high levels of FAS mRNA, which include liver and white adipose tissues. In contrast, CAT reporter activity was not detected in appreciable levels in lung, heart, kidney, and muscle tissues, which do not normally show significant levels of FAS activity. The relative levels of the CAT mRNA driven by the rat FAS promoter in various tissues of the transgenic animals approximated those of the endogenous mouse FAS mRNA. We also examined the hormonal and nutritional regulation of the FAS(2.1)-CAT reporter gene in transgenic mice. CAT activity was increased in both liver and white adipose tissue when fasted animals were refed a high carbohydrate, fat-free diet. These changes in CAT activity and CAT mRNA levels occurred in parallel to the changes in endogenous mouse FAS mRNA levels. On the other hand, fasting/refeeding did not change CAT activity appreciably in other tissues, such as muscle and brown adipose tissue. Administration of dibutyryl cAMP at the start of refeeding prevented an increase in CAT activity in liver. However, the cAMP effect was tissue-specific as cAMP treatment did not bring about change in CAT activity in adipose tissue. Next, to examine the effect of insulin, we made the transgenic mice insulin-deficient by streptozotocin treatment. Insulin treatment of the streptozotocin-diabetic mice increased both the CAT activity and CAT mRNA levels driven by the rat FAS promoter in liver and white adipose tissue. These changes in CAT expression by insulin paralleled those in endogenous FAS mRNA levels. Administration of glucocorticoids increased CAT activity in all tissues examined: liver, white and brown adipose tissues, lung, heart, and spleen. Overall, the first 2.1 kilobases of the 5'-flanking region of the rat FAS gene appear to contain sequence elements necessary to confer tissue-specific and hormonally regulated expression characteristic of the endogenous FAS gene.
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Affiliation(s)
- M Soncini
- Department of Nutritional Sciences, University of California, Berkeley 94720, USA
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Chun JY, Sexton GL, Roth LE, Stacey G. Identification and characterization of a novel Bradyrhizobium japonicum gene involved in host-specific nitrogen fixation. J Bacteriol 1994; 176:6717-29. [PMID: 7961425 PMCID: PMC197029 DOI: 10.1128/jb.176.21.6717-6729.1994] [Citation(s) in RCA: 11] [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: 01/28/2023] Open
Abstract
To understand the genetic mechanism of host specificity in the interaction between rhizobia and their hosts, it is important to identify genes that influence both early and late steps in symbiotic development. This paper focuses on the little-understood genetics of host-specific nitrogen fixation. A deletion mutant of Bradyrhizobium japonicum, strain NAD163, was found to induce effective, nitrogen-fixing nodules on soybean and siratro plants but produced ineffective nodules on cowpea plants. Additional transposon and deletion mutants defined a small region that conferred this phenotype, and this region was sequenced to identify two putative open reading frames (ORFs). Data indicate that only one of these ORFs is detectable in bacteroids. This ORF was termed hsfA, with a predicted protein product of 11 kDa. The transcriptional start site of hsfA was determined and found to coincide with a predicted RpoN-dependent promoter. Microscopic studies of nodules induced by the wild type and hsfA mutants on cowpea and soybean plants indicate that the cowpea mutant nodules are slow to develop. The data indicate that hsfA appears to play a crucial role in bacteroid development on cowpea but does not appear to be essential for nitrogen fixation on the other hosts tested.
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Affiliation(s)
- J Y Chun
- Center for Legume Research, Graduate Program of Plant Physiology and Genetics, Department of Zoology, and Department of Microbiology and Graduate Program of Ecology, University of Tennessee, Knoxville 37996
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Abstract
We have cloned four members of the family of subtilisin-like endoproteases expressed in the bag cell neurons of Aplysia and have demonstrated that two of these enzymes are capable of correctly cleaving the egg-laying hormone precursor. The egg-laying hormone precursor undergoes an ordered series of cleavages, such that different peptides are differentially sorted into distinct secretory vesicles. We have used electron microscopic chemistry to demonstrate that at least one processing enzyme is differentially segregated into a class of secretory vesicles containing the bag cell peptides. The segregation of specific endoproteases, along with specific neuropeptides within a given cell type, may ensure appropriate cleavage and prevent inappropriate cleavage of the polyprotein precursors.
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Affiliation(s)
- J Y Chun
- Department of Biochemistry and Biophysics, College of Physicians and Surgeons, Columbia University, New York, New York 10032
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Chun JY, Stacey G. A Bradyrhizobium japonicum gene essential for nodulation competitiveness is differentially regulated from two promoters. Mol Plant Microbe Interact 1994; 7:248-255. [PMID: 8012043 DOI: 10.1094/mpmi-7-0248] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We report the identification and nucleotide sequence of a new symbiotic gene (nfeC) from the soybean root nodule bacterium, Bradyrhizobium japonicum. A Tn5 insertion (NAD14) in this gene did not affect nitrogen fixation but caused a significant delay in soybean nodulation. In addition, this mutant exhibited a reduction in its competitive ability to nodulate soybean when coinoculated with the wild type. Sequence analysis of the mutated region revealed that the NAD14 Tn5 insertion mapped within an open reading frame of 825 bp. Primer extension using B. japonicum mRNA from three different growth conditions, aerobic, anaerobic, and bacteroids (i.e., symbiotic form) indicated that the upstream region of the gene contained two promoters, which were differentially regulated in response to the growth conditions. One promoter was expressed in bacteroids, but not under aerobic or anaerobic free-living conditions. The other promoter was expressed only under aerobic conditions.
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Affiliation(s)
- J Y Chun
- Center for Legume Research, University of Tennessee, Knoxville 37996-0845
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Stacey G, Luka S, Sanjuan J, Banfalvi Z, Nieuwkoop AJ, Chun JY, Forsberg LS, Carlson R. nodZ, a unique host-specific nodulation gene, is involved in the fucosylation of the lipooligosaccharide nodulation signal of Bradyrhizobium japonicum. J Bacteriol 1994; 176:620-33. [PMID: 8300517 PMCID: PMC205098 DOI: 10.1128/jb.176.3.620-633.1994] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.3] [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: 01/29/2023] Open
Abstract
The nodulation genes of rhizobia are regulated by the nodD gene product in response to host-produced flavonoids and appear to encode enzymes involved in the production of a lipo-chitose signal molecule required for infection and nodule formation. We have identified the nodZ gene of Bradyrhizobium japonicum, whose product is required for the addition of a 2-O-methylfucose residue to the terminal reducing N-acetylglucosamine of the nodulation signal. This substitution is essential for the biological activity of this molecule. Mutations in nodZ result in defective nodulation of siratro. Surprisingly, although nodZ clearly codes for nodulation function, it is not regulated by NodD and, indeed, shows elevated expression in planta. Therefore, nodZ represents a unique nodulation gene that is not under the control of NodD and yet is essential for the synthesis of an active nodulation signal.
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Affiliation(s)
- G Stacey
- Department of Microbiology and Graduate Program of Ecology, University of Tennessee, Knoxville 37996-0845
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Abstract
Genetic elements called retrons reside on the chromosome of Escherichia coli and the myxobacteria and represent the first reverse transcriptase-encoding element to be found in a prokaryotic cell. All known retrons produce a functionally obscure RNA-DNA satellite molecule called multicopy single-stranded DNA (msDNA). We report here the presence of msDNA-producing retron elements in a number of new bacterial groups, including strains of the genera Proteus, Klebsiella, Salmonella, Nannocystis, Rhizobium, and Bradyrhizobium. Among a population of 63 rhizobia strains, only 16% contain a retron element. The rhizobia retrons appear to be heterogeneous in nucleotide sequence and show little similarity to previously studied retrons of E. coli and the myxobacteria.
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Affiliation(s)
- S A Rice
- Department of Microbiology, University of Tennessee, Knoxville 37996-0845
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31
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