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Biomedical subjects

J K Ko

Publications and source records attributed to J K Ko.

40 records · Page 3Linked to original sources
PubMedDate not supplied

Anomalous origin of the right pulmonary artery from the ascending aorta: diagnosis by magnetic resonance imaging.

Anomalous origin of the right pulmonary artery from the ascending aorta is a rare congenital anomaly. Magnetic resonance imaging (MRI) was performed on three patients with anomalous origin of the right pulmonary artery from the ascending aorta. ECG-gated, T1-weighted, spin-echo MRIs and cine MRIs were obtained. In one patient, postoperative MRI was also obtained. Echocardiography and cardiac catheterization were performed in three patients and angiocardiography was performed in two. MRI clearly showed anomalous origin of the right pulmonary artery from the posterior aspect of the ascending aorta, as well as combined anomalies including patent ductus arteriosus, aortopulmonary window, and interruption of the aortic arch in all three patients. Echocardiography missed this anomaly in all three. We suggest that MRI is an accurate imaging modality in diagnosing anomalous origin of the right pulmonary artery from the ascending aorta, obviating the need to perform angiocardiography.

Adult↗
PubMedDate not supplied

MRI of total anomalous pulmonary venous connections.

OBJECTIVE: A prospective MR study was undertaken in 13 patients with total anomalous pulmonary venous connection (TAPVC) to determine the value of MR in its detection. MATERIALS AND METHODS: Echocardiography was performed in all cases and cardiac angiography was performed in eight patients before MRI. RESULTS: Magnetic resonance detected TAPVC in four cases without prior echocardiographic and angiographic diagnosis. In seven surgically proven cases, the diagnostic accuracy of preoperative MR, echocardiography, and cardiac angiography was 100 (7 of 7), 57 (4 of 7), and 25% (1 of 4), respectively. In the remaining cases including three cases for postoperative evaluation, MR findings correlated well with those of echocardiography or angiography. The combination of axial and coronal MRI visualized 96% of the individual anomalous pulmonary veins and 100% of the common pulmonary veins. Stenosis of a common pulmonary vein (three cases) or the superior vena cava (one case) was identified on MR in all cases. CONCLUSION: Magnetic resonance is an effective modality in depicting TAPVCs.

Angiography↗
PubMedDate not supplied

A correlative study on the mechanism of adaptive cytoprotection against ethanol-induced gastric lesion formation in rats.

The protective effect of mild irritants against the subsequent gastric injury induced by necrotizing agents has been termed 'adaptive cytoprotection'. In this study, the possible pathway and mechanisms of adaptive cytoprotection induced by 20% ethanol were investigated. An ex-vivo gastric chamber preparation was used. The gastric mucosa was exposed to 20% ethanol before subsequent administration of 100% ethanol 15 min later. Subdiaphragmatic vagotomy or drug pretreatment was carried out in order to elucidate the mechanisms of adaptive cytoprotection by 20% ethanol. The results showed that 20% ethanol pre-exposure significantly protected the gastric mucosa against damage caused by 100% ethanol. This protective action was completely abolished by atropine or lidocaine pretreatment, whereas vagotomy and hexamethonium failed to have a significant influence. The cytoprotective effect, however, was independent of the gastric secretory volume, titratable acid content, luminal soluble mucus level and gastric mucosal blood flow. Exposure of only half the gastric mucosa to the mild irritant resulted in the protection of both sides of the mucosa. All these findings indicate that the adaptive cytoprotection of 20% ethanol involves the participation of chemoreceptors and muscarinic receptors in the gastric mucosa. An internal enteric reflex arc, with transmission of signals within the gastric mucosa, may also contribute to the cytoprotective process of the mild irritant.

Adaptation, Physiological↗