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Biomedical subjects

A Y Lee

Publications and source records attributed to A Y Lee.

At least 19 recordsLinked to original sources
PubMed1992

Consequences of opiate agonist and antagonist in myocardial ischaemia suggest a role of endogenous opioid peptides in ischaemic heart disease.

OBJECTIVE: The aim was to evaluate the effects of an opiate agonist (U50,488H) and an opiate antagonist (naloxone) in myocardial ischaemia. METHODS: A left thoracotomy was performed and the left coronary artery was ligated in adult Sprague-Dawley rats of either sex (350-400 g). Blood pressure, heart rate and electrocardiogram were measured before and after injections of U50,488H or naloxone and throughout the 30 min postligation period. RESULTS: Following coronary artery occlusion, all rats in the control group developed arrhythmias, bradycardia, and hypotension. U50,488H potentiated and naloxone attenuated the ischaemia induced arrhythmias, bradycardia, and hypotension. CONCLUSIONS: The potentiating and blocking effects of U50,488H and naloxone, respectively, suggest that endogenous opioid peptides are involved in the pathophysiology of myocardial ischaemia and play an important role in ischaemic heart disease.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1992

Stereospecific antiarrhythmic effects of naloxone against myocardial ischaemia and reperfusion in the dog.

1. The effects of both the (-)- and (+)-stereoisomers of naloxone in anaesthetized dogs with arrhythmias induced by acute coronary artery occlusion followed by reperfusion were investigated. 2. Following coronary artery occlusion and reperfusion, all dogs in the control group developed ischaemia- and reperfusion-induced cardiac arrhythmias, bradycardia and hypotension. 3. The opiate antagonist (-)-naloxone prevented the arrhythmias, bradycardia and hypotension due to myocardial ischaemia and reperfusion. 4. The (+)-stereoisomer of naloxone, which is inactive as an opiate antagonist, was without beneficial effects. 5. These results indicate a possible involvement of endogenous opioid peptides in the cardiac effects due to myocardial ischaemia and reperfusion, mediated by opiate receptors through opiate antagonism.

Animals↗
PubMed1992

Antiarrhythmic action of naloxone. Suppression of picrotoxin-induced cardiac arrhythmias in the rat.

The antiarrhythmic properties of the opiate antagonist naloxone have been reported in a variety of models of arrhythmia. To determine the generality and the possible central involvement of its antiarrhythmic activity, the effects of naloxone were assessed against cardiac arrhythmias induced by intravenous bolus injections of picrotoxin. Naloxone at doses of 0.33 and 1 mg/kg significantly reduced the incidence and severity of picrotoxin-induced arrhythmias in a dose-related manner, without alteration of blood pressure and heart rate. The results demonstrate the antiarrhythmic efficacy of naloxone in an additional animal model. They further suggest that the antiarrhythmic actions of naloxone may be mediated by the central nervous system via both the autonomic and GABAergic pathways.

Animals↗
PubMed1992

Naloxone reversal of ischemic arrhythmia is stereospecific and suggests role of endogenous opioid peptides in ischemic heart disease.

The effects of the stereoisomers of naloxone during myocardial ischemia were studied. (-)-Naloxone (but not the (+)-isomer naloxone) attenuated the ischemia-induced cardiac arrhythmias, hypotension, and bradycardia that result from coronary artery occlusion in anesthetized rats. From these findings, it may be inferred that endogenous opioid peptides may play a role in the pathophysiology of myocardial ischemia. It is also suggested that naloxone may have therapeutic value in the prevention and treatment of ischemic heart disease.

Animals↗
PubMed1991

Lobulated intradermal nevus. Report of three cases.

We report the cases of three patients with lobulated intradermal nevi. Biopsy specimens showed similar findings, that is, fatty infiltration within nests of nevus cells, neuroid differentiation of nevus cells, and dermal fibrosis. Our cases probably represent an unusual form of regressing melanocytic nevus.

Adult↗
PubMed1991

Angioblastoma (Nakagawa)--is it the same as tufted angioma?

Four children affected by intradermal vascular proliferations are presented. The clinicopathological findings closely resemble those of cases described as angioblastoma, a familiar entity in the Japanese literature. Some people suggest that angioblastoma is the same as the tufted angioma described by Wilson-Jones. We found localized hyperhidrosis in two of our patients. Proliferation of eccrine glands near the tumour lobule was a consistent finding in the biopsy specimens from these four patients. In one patient, some of the vascular tufts were replaced by mucinous material. These findings have not been mentioned in previous reports of tufted angioma.

Child↗
PubMed1991

Provocation tests in a chlormezanone-induced fixed drug eruption.

Although as few as seven cases of fixed drug eruption (FDE) due to chlormezanone have been reported, it should not be overlooked as a cause of FDE. To identify the causative agent in FDEs, topical provocation tests are much safer and more convenient than systemic provocation tests. If results of topical provocation tests are reliable, they could become useful diagnostic as well as screening tests. Patch tests were performed in a suspected case of FDE due to chlormezanone on the patient's normal and prelesional skin with all ingested drugs whose concentrations were one and ten percent. The base was petrolatum. A positive reaction occurred only at the previously lesional site tested with chlormezanone, and was confirmed with oral provocation tests.

Adult↗
PubMed1990

Effects of drugs interacting with opioid receptors during normal perfusion or ischemia and reperfusion in the isolated rat heart--an attempt to identify cardiac opioid receptor subtype(s) involved in arrhythmogenesis.

Cardiac opioid receptors have been shown to be involved in the genesis of arrhythmias during ischemia and reperfusion. The present study was aimed at elucidating the receptor subtype(s) involved in arrhythmogenesis. Two series of experiments were conducted. In the first, effects of prototype opioid agonists, namely, (D-Ala2, NMe4, Gly-ol)-Enkephalin (DAGO), U50,488H and (D-Pen2, Pen5)-Enkephalin (DPDPE) and (D-Ala2, D-Leu2)-Enkephalin (DADLE), representing mu-, kappa- and delta-agonists, respectively, in disturbing the normal cardiac rhythm in the isolated perfused rat heart were investigated. Both DAGO and U50,488H were arrhythmogenic, whereas the effects of the delta-agonists, DPDPE and DADLE at a same dose range (44-396 nmol/heart) as that of DAGO were almost negligible. U50,488H was by far the most potent as it induced ventricular arrhythmias including frequent PVC and VT even at a dose (44 nmol/heart) at which other agonists either produced no or negligible effect. In the second series of experiments, the antiarrhythmogenic effects of mu-antagonist (naloxone) and kappa-antagonist (MR 2266) against arrhythmias arising during ischemia and reperfusion were compared. The effects of MR 2266 were significantly greater than that of naloxone. Results of the present study suggest that the cardiac kappa-receptors are the most likely receptor-subtype involved in arrhythmogenesis during ischemia and reperfusion.

Animals↗
PubMed1990

A case of allergic contact dermatitis due to nickel in underground water.

A 26-year-old Korean woman with nickel allergy continued to have recurrent facial lesions even after avoiding the usual sources of nickel. As another possible source of nickel, underground water at her house, which had been used by her for 3 years, was analyzed by atomic absorption spectrophotometry. Nickel contents in 8 different domestic tap waters and another underground water sample were also measured by plasma scan. Nickel contents in the patient's underground water were 9 times higher on average than those in domestic tap water. Patch tests with 2 concentrated underground water samples gave positive results. The other underground water sample also contained a higher amount of nickel than tap water. Therefore, we suggest that the underground water was a source of our patient's nickel contact dermatitis, and should be considered as a rare but possible source of nickel contact dermatitis.

Adult↗
PubMed1989

Effects of reserpine treatment on arrhythmogenesis during ischaemia and reperfusion in the isolated rat heart.

1. The effects of reserpine treatment on the myocardial contents of catecholamines and enkephalins and the incidence of ventricular arrhythmias during ischaemia and reperfusion in the isolated rat heart were studied. 2. Reserpine treatment almost completely depleted the heart of noradrenaline (NA). It also significantly depleted the heart of adrenaline and dopamines. It did not, however, alter the myocardial contents of enkephalins. 3. Reserpine-treatment attenuated significantly, but did not abolish, cardiac arrhythmias induced by ischaemia and reperfusion in the isolated heart preparation. 4. The results of the present study indicate that myocardial catecholamines especially NA are a contributing factor to arrhythmogenesis during ischaemia and reperfusion.

Animals↗
PubMed1989

Cardiovascular effects of central administration of beta-endorphin in rats receiving neonatal injection of monosodium glutamate.

1. The effects of intracerebroventricular (i.c.v.) and intracisternal (i.c.) injection of beta-endorphin on arterial blood pressure (BP) in rats that received five intraperitoneal injections of monosodium glutamate (MSG) on alternate days in the first 10 days of life were studied. 2. beta-endorphin administered into the lateral ventricles caused a prolonged elevation in BP, whereas i.c. injection of the peptide resulted in an even longer lasting reduction in BP. In the MSG-treated rat, the prolonged hypertensive effect of i.c.v. injection of beta-endorphin was completely abolished, but the effect of i.c. injection of the peptide was the same as that in the control. Since MSG treatment destroyed selectively the structures around the third ventricle, it is suggested that these structures, including the arcuate nucleus, may be responsible for mediating the cardiovascular effects of beta-endorphin. 3. The effects of central administration of beta-endorphin were completely blocked by naloxone, which mainly antagonizes the actions of mu-receptor agonists and has no cardiovascular effects itself. The results suggest that mu-receptors may be involved in mediation of the effects of beta-endorphin on the cardiovascular system and that beta-endorphin in the brain may not exert a tonic influence on the cardiovascular functions.

Animals↗
PubMed1989

Erythema elevatum diutinum: an ultrastructural case study.

An electron microscopic study was made of a patient with erythema elevatum diutinum, a rare variant of cutaneous leukocytoclastic vasculitis. Biopsies were obtained from early evolving and late fibroproliferative lesions. Early lesions showed vasculitis and a massive dermal infiltrate composed mainly of neutrophils, histiocytes/macrophages and apparently increased Langerhans cells. Later lesions were characterized by a dense fibrosis with a proliferation of fibroblasts and myofibroblasts and a dermal infiltrate in which lymphocytes and histiocytes/macrophages predominated. Even in later lesions, dermal Langerhans cells were observed in great number. Langerhans cells may be involved in the evolution of this rare disease.

Erythema↗
PubMed1987

Effects of dynorphin1-13 on cardiac rhythm and cyclic adenosine monophosphate (cAMP) levels in the isolated perfused rat heart.

We have studied the effects of dynorphin1-13 on cardiac rhythm and cAMP levels in the isolated perfused rat heart. The standard Langendorff isolated heart preparation was used. The myocardial cAMP levels and the incidence of cardiac arrhythmias were determined after injection of dynorphin1-13. Dynorphin1-13 caused simultaneously cardiac arrhythmias and an increase in myocardial cAMP levels in a dose-dependent manner, and both effects were antagonized by naloxone. Further studies are needed to determine whether myocardial cAMP mediates the dynorphin-induced cardiac arrhythmias.

Animals↗
PubMed1987

Chronic morphine treatment reduces the incidence of ventricular arrhythmias in the isolated rat heart induced by dynorphin1-13 or myocardial ischemia and reperfusion.

We have studied the effects of a daily morphine injection for 2 weeks on induction of naloxone-reversible arrhythmias in the Langendorff isolated rat heart preparation caused by dynorphin1-13 or myocardial ischemia and reperfusion. Chronic morphine treatment significantly reduced the incidence and severity of arrhythmias and increased recovery following both administration of dynorphin and myocardial ischemia and reperfusion. The results support the notion that myocardial ischemia and reperfusion induce cardiac arrhythmias via endogenous opioid peptides.

Animals↗