Biomedical subjects
Y Y Hsieh
Publications and source records attributed to Y Y Hsieh.
Coronary heart disease and hypertension in Taiwan aborigines.
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The clinical application of vectorcardiography: vectorcardiographic analysis in 80 normal Chinese with particular emphasis on the methods of analysis.
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Sonographic diagnosis of triplet tubal pregnancy after in vitro fertilization and embryo transfer.
Ectopic pregnancy (EP) after in vitro fertilization and embryo transfer (IVF/ET) is not rare, but triplet tubal pregnancy after IVF/ET is very rare. We describe a patient with hydrosalpinx in whom a triplet tubal pregnancy occurred on the same side as the hydrosalpinx. Close hormonal and sonographic monitoring of pregnancies achieved through IVF is recommended to ensure the early diagnosis of EP and to avert complications. A triplet tubal EP was considered highly probable after 3 gestational sacs were observed outside the uterus during sonography performed at 6 weeks' gestation. Therapeutic laparoscopy was then performed because methotrexate treatment failed. Appropriate management strategies are discussed.
Newer catecholamines for treatment of heart failure and shock: an update on dopamine and a first look at dobutamine.
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Hemodynamic consequences of administration of phentolamine or nitroprusside with dopamine in the dog.
Dopamine was administered intravenously to two groups of anesthetized dogs at rates of 2.5, 5, 10 and 20 micrograms/kg/min. After the 20 micrograms/kg/min infusion, mean arterial pressure, heart rate, renal blood flow, mean pulmonary arterial pressure, and left ventricular filling pressure were increased. The dopamine infusion was continued in both groups of animals. In Group I phentolamine was administered at rates of 2.5, 5, and 7.5 micrograms/kg/min; in Group II sodium nitroprusside at rates of 1, 2, 3, and 4 micrograms/kg/min. Phentolamine and sodium nitroprusside produced similar reductions in mean arterial blood pressure, mean pulmonary arterial pressure, left ventricular filling pressure, and similar increments in heart rate. Renal blood flow was maintained with phentolamine infusions and decreased slightly with the nitroprusside infusions. These studies demonstrated that both phentolamine and nitroprusside have the ability to reduce the vasoconstricting effects of dopamine.
Chronotropic effects of atropine sulfate and methscopolamine bromide in normal subjects and patients undergoing cardiac catheterization.
The increase in heart rate caused by intravenous injections of atropine sulfate (AS) and methscopolamine bromide (MSB) were compared in 12 healthy volunteers. AS, 200 micrograms, or MSB, 100 micrograms, were injected every 3 min for five doses on successive days. Mean heart rate from the second and fifth injections of MSB was significantly greater than after corresponding injections of atropine. The ratio of equivalent doses of MSB and AS was found to be 1:3. Three subjects with AS and four subjects with MSB exhibited reduced heart rates after the first injection. Excellent correlation of plasma atropine concentrations and heart rate increase were obtained in two volunteers (correlation coefficient, r = 0.84). In the second study, AS, 180 micrograms, and MSB, 60 micrograms, were compared in 20 patients undergoing cardiac catheterization and coronary arteriography. Both drugs produced equivalent increments in heart rate. MSB produced a more predictable dose response than AS. Side effects were similar with both drugs when equivalent doses were used. This study confirms previous investigations that MSB can be titrated by intravenous injections to increase heart rate to desired levels. Absence of central nervous system stimulation by MSB suggests that it may be more appropriate for use in patients with myocardial infarction.
Enantioselectivity of microsomal and cytosolic esterases in rat intestinal mucosa.
Enantioselectivity of esterases, contained in 9,000g supernatant fraction (S9) prepared from homogenate of small intestinal mucosa of male Sprague-Dawley rats and the subsequent 105,000g supernatant (cytosol) and pellet (microsomes) prepared from S9, was studied using racemic oxazepam 3-acetate (rac-OXA) as the substrate. Esterases in S9 were enantioselective in hydrolyzing either S-OXA or R-OXA, depending on a particular subcellular preparation. Cytosolic and microsomal esterases had opposite enantioselectivity and selectively hydrolyzed S-OXA and R-OXA, respectively. Enantioselectivity of esterases solubilized from microsomes with Triton X-100 (0.1%, w/v) was identical to that of the membrane-bound microsomal esterases. Cytosolic esterases were more sensitive to temperature than either solubilized or membrane-bound microsomal esterases. In the presence of paraoxon (1 microM), the esterases selective toward R-OXA in both microsomes and S9 were completely inhibited, whereas the esterases selective toward S-OXA in cytosol were inhibited by approximately 6%. These results indicate that cytosolic and microsomal esterases in rat small intestinal mucosa are distinctly different enzymes, with opposite enantioselectivity in the hydrolysis of rac-OXA.