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Biomedical subjects

Y J Lim

Publications and source records attributed to Y J Lim.

At least 37 records · Page 2Linked to original sources
PubMed2000

Positioning of a double-lumen endobronchial tube without the aid of any instruments: an implication for emergency management.

BACKGROUND: Lung isolation and preservation of normal lung are the first lines of therapy in life-threatening massive hemoptysis. If bleeding continues but the side of origin is uncertain, use of a double-lumen tube (DLT) is reasonable. Utilizing a blind method to locate the bronchial cuff of a left-sided DLT without using any instrument, a DLT (Broncho-Cath, Mallinckrodt Medical Ltd., Athlone, Ireland) was successfully positioned without delay in a patient with massive hemoptysis, where auscultation could be misleading or useless and fiberoptic bronchoscope (FOB) was inapplicable. This study was performed to discern whether this blind method could substitute for FOB verification or auscultation in most circumstances where these two methods are unavailable or inapplicable. METHODS: After receiving informed consent and hospital ethics board approval, 58 elective thoracic surgical patients, aged 17 to 67 years, were enrolled in the study and divided into two groups. A conventional method using an FOB was used to locate the left-sided DLT in 29 patients (group 1). In the other 29 patients (group 2), the blind manual method was used. The left-sided DLT was inserted until some resistance was felt, at which time the bronchial cuff was inflated with approximately 2.0 mL of air. While gently holding the pilot with thumb and index finger of the nondominant hand, the DLT was slowly withdrawn until an abrupt decrease of pilot pressure was sensed. At that moment, the bronchial cuff was deflated, and the DLT was advanced approximately 1.5 cm; using an FOB, its position was checked by an independent observer not involved in positioning the DLT. Success was defined as the point when the proximal margin of the carina was within the margin of safety for the DLT, which is defined as the difference between the length of the left main bronchus and the length of the tube between the proximal margin of the left bronchial cuff and the left lumen tip. Postoperative FOB was performed to evaluate bronchial injury. RESULTS: In 26 of 29 patients (group 2), the position of the DLT was bronchoscopically confirmed to be a success. The other three cases were deemed to be too shallow; specifically, the bronchial cuffs were slightly herniated onto the carina (acceptable position). This method was more traumatic than FOB-guided DLT intubation (conventional method) (p = 0.001); however, the most severe damage was erosion. CONCLUSION: This method, which requires no specific instrument and no time-consuming technique, can be taught easily and may be used in a situation where the rapidity of lung isolation or collapse is the key to saving life. We conclude that this blind method can be an alternative to the FOB and/or auscultation for the positioning of DLT in an emergency situation.

Adolescent↗
PubMed2000

A novel factor isolated from Actinobacillus actinomycetemcomitans stimulates mouse B cells and human peripheral blood mononuclear cells.

A novel immunostimulating factor (ISTF) of Actinobacillus actinomycetemcomitans ATCC 29522 was isolated and characterized as inducing proliferation of mouse B cells and human peripheral blood mononuclear cells. This factor was isolated from the bacterial culture medium and purified by size exclusion chromatography, dye-ligand affinity chromatography, immunoaffinity chromatography using monoclonal antibodies, and preparative electrophoresis. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the purified ISTF migrated as a single band corresponding to a molecular mass of 13 kDa. ISTF was a proteinaceous material distinct from lipopolysaccharide; it directly induced the proliferation of B lymphocytes but had no effect on the proliferation of T lymphocytes, even in the presence of antigen-presenting cells. A B-lymphocyte-mitogenic activity of ISTF was also shown by flow cytometric analysis of responding cell subpopulations. Immunoblot analysis revealed that ISTF was a component of the outer membranes of bacteria, could exist as a soluble form, and was released by growing and/or lysed bacteria. These results suggest that ISTF produced by A. actinomycetemcomitans may play an important role in immunopathologic changes associated with A. actinomycetemcomitans infections.

Adjuvants, Immunologic↗
PubMed2000

Murine bone marrow-derived mast cells exhibit evidence of both apoptosis and oncosis after IL-3 deprivation.

IL-3 deprivation has been reported to induce apoptosis of bone marrow-derived mast cells. In order to evaluate this type of cell death further, we employed trypan blue and propidium iodide stainings, photometric enzyme immunoassay, fluorescence measurement of caspase-3, DNA electrophoresis, flow cytometry and transmission electron microscopy. In this experiment, although several evidences supporting apoptosis were demonstrated some findings were not consistent with typical apoptosis. On the other hand, electron microscopical observation demonstrated that most cells from all the time phases after IL-3 deprivation showed the morphology of typical oncosis, i.e. cell swelling, disintegration of ultrastructure and subsequent karyolysis. Only a small number of cells from the later time phases showed apoptotic morphology. We here suggest that BMMCs undergo both apoptosis and oncosis after IL-3 deprivation and that the dominant type of prelethal change is oncosis in all time phases, although apoptosis also plays a partial role in the late time phases.

Animals↗
PubMed2000

Activated platelets induce secretion of interleukin-1beta, monocyte chemotactic protein-1, and macrophage inflammatory protein-1alpha and surface expression of intercellular adhesion molecule-1 on cultured endothelial cells.

Atherosclerosis is an inflammatory disease. Platelet-endothelium interaction plays an important role in the pathophysiology of atherogenesis. We investigated the role of activated platelets for secretion of interleukin (IL)-1beta, monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1alpha and expression of intercellular adhesion molecule (ICAM)-1 on endothelial cells. Human umbilical vein endothelial cells (HUVEC) were incubated with non-stimulated or ADP-activated platelets for 6 hr. Secretion of interleukin (IL)-1beta, MCP-1 and MIP-1alpha and surface expression of ICAM-1 were measured by ELISA and flow cytometry. In the presence of activated platelets, the secretion of IL-1beta, MCP-1, and MIP-1alpha and surface expression of ICAM-1 were significantly increased compared with non-activated platelets. The present study shows that activated platelets may contribute to expression of various inflammatory mediators on endothelial cells.

Blood Platelets↗
PubMed1999

Cytotoxic polyacetylenes from the marine sponge Petrosia sp.

Three C46 (1-3) and three C30 (4-6) polyacetylenic alcohols with cytotoxic activity against a small panel of human solid-tumor cell lines have been isolated from the marine sponge Petrosia sp. Although compound 1 was identified as the stereoisomer of petrocortyne A, the structures of compounds 2-5 have not been previously reported and were established by spectral methods. Compound 6 was identified as the known compound petrosiacetylene D. The stereochemistry of compounds 1-5 was determined by the modified Mosher's method.

Acetylene↗
PubMed1999

New cytotoxic polyacetylenes from the marine sponge Petrosia.

New polyacetylenic alcohols with a C(45) carbon skeleton (2) and with an enone moiety in the alkyl chain (C(46), 1) were isolated from the marine sponge Petrosia sp. The gross structures of 1 and 2 were established by spectral methods, and the absolute stereochemistry was determined by the modified Mosher's method. Compounds 1 and 2 displayed considerable cytotoxicity against a small panel of human solid tumor cell lines. Significant inhibitions on DNA replication by 1 and 2 were also observed which could be explanative of their cytotoxicity.

Acetylene↗
PubMed1999

Cerebral infarction with ICA occlusion after Gamma Knife radiosurgery for pituitary adenoma: A case report.

Cranial irradiation may lead to accelerated atherosclerotic changes to small or medium sized arteries, but stroke associated with pituitary irradiation is not frequent. A patient treated with Gamma Knife radio-surgery (GKRS) for a pituitary adenoma suffered a cerebral infarction with internal carotid artery occlusion 4 years after radiosurgery. The patient was a 35-year-old male presenting with a visual disturbance. Endocrinological tests were normal. MRI revealed a 4.3 by 4.3 cm diameter invasive macroadenoma of the pituitary, projecting toward the suprasellar region and with cavernous sinus involvement with encasement of both internal carotid arteries (ICAs). GKRS was performed for residual tumor after a transcranial resection. The maximum dose was 40 Gy and the dose to the right carotid artery was below 20 Gy. The delayed hemiparesis was accompanied by a right capsular lacunar infarct shown on MRI. The images also showed a marked reduction in tumor size. Total, right ICA occlusion was confirmed by Doppler ultrasound. The patient had no history or signs of heart disease or metabolic disorder which could predispose to cerebrovascular

Adenoma↗
PubMed1999

Effect of alpha/gamma phase ratio on corrosion behavior of dual-phase stainless steels.

Dual-phase stainless steels have been developed in order to reduce the nickel content, which is potentially responsible to an allergic reaction when these steels are used as medical or dental applications. In this study, two different dual-phase stainless steels (2205 and Z100) were electrochemically tested to evaluate their corrosion resistance in three corrosive solutions (i.e., synthetic saliva, 0.9% NaCl solution, and Ringer solution). Particularly, an attempt was made to correlate the corrosion resistance to a metallographic parameter, which is, in this study, the alpha/gamma phase ratio. It was concluded that (1) type 2205 stainless steel exhibited excellent corrosion resistance in all three corrosion media; however 2205 stainless steel decreases its corrosion resistance by increasing chloride concentration in tested electrolytes from synthetic saliva through 0.9% NaCl solution to Ringer solution. (2) X-ray diffraction analysis indicated that the alpha/gamma phase ratio of 2205 (1.735) was higher than that of Z100 (0.905). As a result, it is suggested that by increasing the alpha/gamma phase ratio the material shows more corrosion-prone behavior when being subjected to a hostile environment containing higher chloride ion concentration.

Chemical Phenomena↗
PubMed1998

Spreading pattern of epidurally administered contrast medium in rabbits.

BACKGROUND: The aim of this study was to examine the precise spreading pattern of epidurally administered contrast medium with small increments of injection volume for determining both the exact volume of the dose required and the site of epidural injection according to different target segments of the spinal cord in a rabbit epidural model. METHOD: Following pentobarbital anesthesia, the epidural puncture was done surgically with a round-tipped blunt hook. The tip of the epidural catheter was located at either the mid-portion of T7 (T7 group, n = 7) or T12 (T12 group, n = 8). Injection of the contrast medium was started at 0.1 ml/kg and increased by 0.1 ml/kg up to a maximum of 0.6 ml/kg. RESULTS: In both groups, the extent of spread increased continuously with increasing injected volume (T7 group: r2 = 0.91, P = 0.0001; T12 group: r2 = 0.86, P = 0.0001) and the total spread of contrast medium was similar. However, the spread was not linearly volume dependent. The total number of segments (y) through which the contrast medium spread during changes in its volume (x) in the T7 and T12 groups was calculated as y = 4.0 + 41.8x - 28.1x2 and y = 0.2 + 57.7x - 43.5x2, respectively. The contrast medium spread in both rostral and caudal directions, equally from the catheter tip in the T7 group, whereas it spread rostrally about twice as far as it spread caudally in the T12 group (P < 0.05). CONCLUSION: In rabbits, it is recommended that at the lower thoracic or lumbar segments the tip of the epidural catheter should be located 1-3 segments below the target segment because of more rostral spread. In the case of mid-thoracic segments, however, placement at the target segment is recommended. In addition, a small titration of volume to achieve a particular range of epidural spread should be required.

Animals↗
PubMed1998

Risk factors for breakthrough varicella in healthy children.

AIM: To evaluate the risk factors for breakthrough varicella in a follow up study of a cohort of 181 healthy children immunised when aged 9-24 months with a reformulated Oka strain varicella vaccine (SmithKline Beecham Biologicals/Oka). DESIGN: The children were randomised in a double blind manner into one of four groups to receive one of two production lot vaccine batches, at two different titres (high titre, 10(3.9) and 10(4.0) plaque forming units (pfu); low titre (heat exposed), 10(2.7) and 10(2.8) pfu). The overall seroconversion rate after immunisation was 99%. RESULTS: One hundred and sixty-eight patients were available for review after a mean (SD) follow up of 35 (9) months after vaccination. Multivariate analysis indicated that risk factors for breakthrough varicella were household contact with varicella (adjusted odds ratio (OR), 19.89; 95% confidence interval (CI), 18.39 to 21.39), vaccination age of < or = 14 months (adjusted OR, 2.30; 95% CI, 1.69 to 2.90), and receiving low titre (10(2.7) pfu) vaccine (adjusted OR, 2.13; 95% CI, 1.54 to 2.73). All children who developed breakthrough varicella, had a modified varicella illness, except for three, all of whom had received low titre vaccine. CONCLUSION: The identification of young immunisation age (< or = 14 months) and low titre vaccine as risk factors for breakthrough varicella have important implications for the implementation of varicella vaccination programmes in healthy children.

Age Factors↗
PubMed1998

Sinus histiocytosis with massive lymphadenopathy. Multiple skull involvements.

Sinus histiocytosis with massive lymphadenopathy is a non-neoplastic self-limiting disease of the bone marrow stem cell origin. It is characterized by painless, bilateral cervical lymphadenopathy accompanied by fever, leukocytosis, elevated erythrocyte sedimentation rate and hypergammaglobulinemia. Extranodal involvement including bone is rare. The patient is a 45-year -old female with multiple punch out lesions on her skull. MRI findings included iso-signal intensity mass at the diploid space on T1 weighted image and on T2 weighted image, mild high signal intensity was obtained. Histologically, the lesion showed proliferation of histiocytes in the fibroblastic background with formation of reactive germinal centers and many plasma cells. The histiocytes show round nuclei and occasional nucleoli and abundant cytoplasms. In area, there is lymphocytophagocytosis. Immunohistochemically, the histiocytes were positive for S-100 protein and lysozyme.

Female↗
PubMed1998

[Intrapulmonary arterial injection of Albunex for left heart contrast echocardiography].

Contrast enhancement of the left heart cavity and myocardium were assessed after venous injection of the ultrasound contrast agent Albunex. Myocardial perfusion was also assessed using a drug stress and image analyzing system. The study population consisted of 46 patients with normal cardiac function and without coronary artery disease, and 38 patients with effort angina. Contrast echocardiography was performed by imaging the parasternal or apical long-axis view during pulmonary arterial injection of Albunex through a Swan-Ganz catheter. Contrast enhancement in the left ventricular cavity and ascending aorta were visually assessed. Hemodynamic, arterial blood gas and electrocardiography changes were recorded before and after the injection of Albunex. Contrast echocardiography was performed before and during intravenous infusion of dipyridamole to assess left ventricular myocardial enhancement by both visual inspection and peak background-subtracted gray level using an image analyzing system. Doppler flow signal change after the injection of Albunex was assessed in 26 patients using a Doppler guide wire located in the left anterior descending coronary artery. Good contrast enhancement was obtained in all patients in the left ventricular cavity and in 17% of patients in the ascending aorta. No significant changes were observed in hemodynamics, electrocardiograms and aortic gas analysis. Significant myocardial enhancement was not seen in any patient but gray level analysis of the echo images during dipyridamole infusion showed significant enhancement in 25% of the patients without coronary artery disease and in 34% of the patients with effort angina. Doppler flow signal in the coronary artery was significantly augmented in all patients after injection of Albunex and suggests that ultrasound contrast agent reaches coronary arteries in all patients regardless of myocardial contrast enhancement. Contrast echocardiography with pulmonary arterial injection of Albunex is safe and useful to obtain sufficient left ventricular contrast enhancement. For myocardial perfusion assessment, further refinement of the ultrasound contrast agent and echo equipment is necessary.

Adult↗
PubMed1998

[Apical filling abnormality in patients with heart failure assessed with contrast echocardiography using venous injection of Albunex].

Contrast echocardiography by venous injection of Albunex was used to visualize apical filling abnormality in patients with heart failure. 1. Contrast echocardiography was serially performed in 24 patients with acute anterior myocardial infarction. Wall motion of the infarct region was better at any stage in patients without apical filling abnormality than in patients with that. Improvement of filling abnormality was observed prior to that of wall motion abnormality. 2. Influence of tachycardia was assessed on apical filling in 20 patients with old myocardial infarction during rapid atrial pacing. Stress contrast echocardiography evidenced that tachycardia deteriorates apical filling abnormality in patients with chronic heart failure. 3. The effect of amrinone on apical filling was assessed in 60 patients with chronic anterior myocardial infarction. Apical filling abnormality improved in 46% of patients after amrinone infusion. The improvement of apical filling abnormality was closely related to the reduction of preload and improvement of asynergy in the infarct area after amrinone. Both adjunctive therapy and anticoagulant therapy should be considered if apical filling abnormalities are observed by contrast echocardiography.

Albumins↗
PubMed1997

Comparison of myocardial contrast echocardiography and coronary angiography for assessing the acute protective effects of collateral recruitment during occlusion of the left anterior descending coronary artery at the time of elective angioplasty.

To assess the immediate change in collateral flow distribution within the occluded myocardium and the acute protective effects on myocardial ischemia after coronary occlusion, myocardial contrast echocardiography (MCE) was performed in 15 patients with normal left ventricular function undergoing elective coronary angioplasty of the left anterior descending artery, and the results were compared with those obtained from coronary angiography (CA). The sonicated or nonsonicated contrast material was injected into the right coronary artery before and during coronary occlusion and collaterals were graded on a 4-point scale (none = 0 to good = 3). Development of subjective anginal symptoms, ST-segment shift and wall motion abnormality during coronary occlusion were graded on a 4-point scale (none = 0 to severe = 3). Both MCE and CA detected a significant development in collateral flow during coronary occlusion. There was no significant correlation between MCE and CA collateral grades before or during coronary occlusion. The collateral flow assessed with MCE was inversely but significantly correlated with development of subjective anginal symptoms (r(s) = -0.70, p <0.01), ST-segment shift (r(s) = -0.78, p < 0.005) or wall motion abnormality (r(s) = -0.91, p < 0.001) during coronary occlusion. In contrast, the angiographic collateral flow was not correlated with development of anginal symptoms (r(s) = -0.46, p = 0.10), ST-segment shift (r(s) = -0.41, p = 0.14), or wall motion abnormality (r(s) = -0.26, p = 0.35). The present study suggested that the acute protective effects of coronary collaterals during coronary occlusion were closely associated with myocardial perfusion rather than the angiographic epicardial collateral vessel filling, and thus MCE was useful in assessing the acute protective effects of coronary collaterals during coronary occlusion.

Aged↗
PubMed1997

Salutary effect of adjunctive intracoronary nicorandil administration on restoration of myocardial blood flow and functional improvement in patients with acute myocardial infarction.

Salutary effect of nicorandil, a K+ adenosine triphosphate channel opener, on restoration of myocardial blood flow and functional improvement after coronary revascularization was investigated in 20 patients with first anterior acute myocardial infarction. Ten patients received intracoronary administration of nicorandil (2 mg) after coronary revascularization; the other 10 patients received coronary revascularization only and served as control subjects. Myocardial contrast echocardiography and two-dimensional echocardiography were performed to assess microvascular integrity and regional function in the infarcted area. Nicorandil improved peak contrast intensity ratio (p < 0.001), calculated as the ratio of peak contrast intensity in the infarcted and noninfarcted areas, indicating the restoration of myocardial blood flow to the infarcted myocardium. Regional wall motion improved more significantly in 1 month in patients who received nicorandil (p < 0.01). Thus our results suggested the usefulness of intracoronary nicorandil administration after coronary revascularization for restoring blood flow and functional improvement in patients with acute myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed1997

Different mechanisms of ischemic adaptation to repeated coronary occlusion in patients with and without recruitable collateral circulation.

OBJECTIVES: The aim of this study was to investigate the interaction between ischemic preconditioning (IP) and collateral recruitment (CR) during ischemic adaptation in patients. BACKGROUND: The mechanism of ischemic adaptation still remains controversial in humans. METHODS: The clinical, electrocardiographic, hemodynamic and echocardiographic responses to three 150-s occlusions of the left anterior descending coronary artery were assessed in relation to CR in 18 patients with effort angina undergoing elective percutaneous transluminal coronary angioplasty. RESULTS: During the first occlusion, recruitable collateral circulation (RCC) to the occluded myocardium was detected by myocardial contrast echocardiography in 6 patients (Group C) and was not seen in 12 (Group N). In Group N, all patients manifested signs of severe ischemia during each inflation. However, their symptoms and ST segment shift significantly decreased from the first to the third occlusions, suggesting the occurrence of IP. The elevation of mean pulmonary artery pressure and deterioration of anterior wall motion were comparable between the first and the third occlusions in Group N. In contrast, myocardial ischemia was significantly less marked during occlusion in Group C than in Group N, and no preconditioning effect was observed. The extent of RCC did not differ between the first and the third occlusions in each group. CONCLUSIONS: Both IP and CR may play independent roles in ischemic adaptation in humans. With RCC, myocardial ischemia was greatly reduced. Without RCC, preconditioning clinically and electrocardiographically lessened myocardial ischemia but failed to preserve left ventricular function.

Angina Pectoris↗