Intraarterial Thrombolysis for Central Retinal Artery Occlusion / 신경중재치료의학

Central retinal artery occlusion (CRAO) typically causes severe and permanent visual loss in the affected eye and vision does not recover in 90% of the patients. It is believed that it occurs by occlusion of the central retinal artery with small emboli from atherosclerotic plaque of internal cerebral artery. Various methods have been introduced to recanalize the occluded artery and remove emboli but considered to fail except thrombolytic therapy. Retina is a part of the brain so basically CRAO is corresponding to acute occlusion of intracerebral artery and retinal ischemia is to cerebral stroke. Accordingly rapid procedure within therapeutic time window, choosing appropriate drugs and doses, reducing hemorrhagic and ischemic complications associated with neurovascular intervention is very important. However, clinical significance of CRAO is much different from that of acute cerebral arterial occlusion, therefore, neurointerventionists should perform this procedure within appropriate range of safety.

Probing the Utility of Vascular Smooth Muscle Cells as a Target Cell for ex vivo Cardiovascular Gene Therapy

BACKGROUND AND OBJECTIVES: Compared to other target cells examined for gene therapy, vascular smooth muscle cells (VSMCs) have the unique advantages including proximity to blood stream and relative abundance in vasculature. With an ultimate goal of developing VSMC-based therapies for cardiovascular disorders, we explored the utility of VSMC as a target cell for ex vivo gene therapy using a set of retroviral vectors. MATERIALS AND METHODS: Cultured VSMCs were transduced with replication-defective recombinant retroviruses harboring LacZ, nlsLacZ, mVEGF, mGM-CSF or bacterial CAT reporter. The VSMCs were examined for G418-selection, transduction efficiency, the level of transgene expression, and longevity of gene expression. ResultsVSMCs were readily transduced with different kinds of retroviral vectors. The bacterial neo r gene-transduced VSMCs were successfully selected with G418. The G418-selected VSMCs could express the transduced genes at a level comparable to NIH3T3. The level of transgene expression did not appear to be affected by the increasing number of passages. CONCLUSION: The results demonstrate an efficient transduction of VSMCs by retroviral vectors in vitro and an sustained expression of retrovirally transduced genes in VSMCs. VSMCs could be one of the ideal target cells for ex vivo cardiovascular gene therapy employing retroviral vector.

The Effects of Aldosterone and Cytokines IL-1beta, TNF-alpha on the Expression of Angiotensin Converting Enzyme Gene in Vascular Smooth Muscle Cells

BACKGROUND: It has been suggested that all components of the renin-angiotensin-aldosterone system (RAAS) are present in the vascular wall and that the vascular RAAS modulates vascular tone and vascular hypertrophy. One of the catalytic step in the RAAS cascade is the local conversion of angiotensin I to angiotensin II (Ang II) by angiotensin converting enzyme (ACE). One of the major sources of ACE in the vasculature is vascular smooth muscle cells (VSMC). Here, we provide insight into the intrinsic mechanisms by which the components of RAAS regulate gene expression of ACE in cultured smooth muscle cells of the rat and we also investigated the effects of cytokines on ACE mRNA. METHODS: RNA was extracted from the primary cultured VSMCs. We analyzed the expression levels of ACE by competitive reverse transcription-PCR using recombinant RNA as an internal standard. RESULTS: 1) ACE mRNA level was increased markedly by aldosterone in a dose- and time-dependent manner, indicating that there exists positive feedback mechanism within RAAS. 2) The induction of ACE mRNA by aldosterone was inhibited by spironolactone. 3) Aldosterone-stimulated expression of ACE was also inhibited by Ang II, which shows that Ang II acts as a negative regulator of the expression of ACE in RAAS cascade. 4) Interleukin-1beta or TNF-alpha did not induce ACE mRNA expression. 5) However, mixture of interleukin-1betaand TNF-alpha(CytoMix) significantly increased the expression of ACE. It was also shown that CytoMix increased aldosterone-stimulated ACE mRNA expression in an additative manner. CONCLUSION: These results indicate that the expression of ACE in smooth muscle cells is modulated by the components of RAAS and cytokines. The intrinsic positive and negative feedback controls of RAAS would play an important role in the pathogenesis of vascular diseases.

Gene Transfer into Cultured Cardiac Myocytes Mediated by Retrovirus

BACKGROUND: Transplantation of cardiac myocytes (CMs) into the injured heart emerges as a potential alternative for the treatment of heart failure. Genetic modification of CMs could enhance and/or modify its therapeutic effects. The characteristics of retroviral gene delivery, which is most commonly used in human trial, has been minimally studied in CMs due to its low efficiency in non-dividing cells. In this study, using newly developed high-titer retrovirus, we evaluated 1) the efficiency of gene transfer into CMs, 2) whether S phase during infection is necessary for the transduction, and 3) characteristics of gene delivery to mononucleated vs binucleated CMs. METHODS: Enriched CMs were cultured from the ventricles of 1 day-old rat hearts. The cells were transduced by MFG-nls-LacZ retroviruses (5x107 IU/ml) in the presence or absence of polybrene. 3H-thymidine was added to label cells in S phase. The cells were stained for b-galactosidase activity and then immunostained using MF20Ab to identify CMs. The cells were subsequently processed for in vitro autoradiography. RESULTS: 1)With 3 rounds of infection, 5.9% of total cultured cells were LacZ-positive. The efficiency of transduction reached upto 7.4% in the presence of polybrene 8 microgram/ml. 2)Nuclear morphology of LacZ-positive CMs was pleomorphic from mononucleated to multinucleated, mostly binucleated. 3)Among mononucleated CMs, 17% of cells were labelled with thymidine. Transduction efficiency (TDE) of thymidine-positive and -negative mononucleated CMs were 37.9% and 3.1%, respectively. Among binucleated cells, 28.9% of cells were labelled with thymidine. TDE of thymidine-positive and -negative binucleated CMs were 75.4% and 13.6%, respectively. 4)In total, TDE of binucleated cells were 3.5 times compared to the one of mononucleated cells (31.5% vs 9.0%). CONCLUSION: TDE of CMs using high-titer retrovirus is relatively low. S phase of cells during retroviral infection is not mandatory for the retroviral transduction. Binucleated CMs are susceptible to retroviral gene delivery and their TDE is higher than the one of mononucleated CMs.

Acute Respiratory Failure Caused by Aspiration of High Density Barium: A Case Report

Accidental aspiration of barium contrast medium during the upper gastrointestinal study can occur in patients with swallowing disorder, especially in the elderly patients. We experienced a case of respiratory failure followed by death within a few hours in a 85 year-old patient after barium aspiration.