Two-dimensional echocardiographic demonstration of multiple needles in the heart.
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Adult↗
Biomedical subjects
B N Chiang
Publications and source records attributed to B N Chiang.
Inhibition of the mitochondrial Mg2+-ATPase by propranolol.
The in vitro effects of propranolol, a commonly used beta-adrenergic blocker, on the membrane structure and function of rat heart mitochondria were investigated. It was found that the respiratory control and oxidative phosphorylation of the isolated mitochondria decreased concomitantly when the drug was added to the assay medium. At the concentration higher than 1.0 X 10(-4) M, propranolol significantly inhibited the State 3 respiration but had little effect on the State 4 respiration of the mitochondria. On the other hand, the drug exhibited noncompetitive inhibitions toward the Mg2+-ATPase activity of submitochondrial particles and purified enzyme preparations at the concentrations ranging from 3.0 X 10(-4) to 1.5 X 10(-3) M. The inhibitory constants of propranolol toward the enzyme activity in submitochondrial particles and in the purified preparation were estimated to be 6.7 X 10(-4) and 1.4 X 10(-3) M, respectively. However, the drug did not show significant effect on the activity of any of the enzyme complexes of the mitochondrial respiratory chain. It is thus concluded that propranolol impairs the mitochondrial respiration and oxidative phosphorylation mainly through its inhibition of the Mg2+-ATPase activity of the mitochondria. This effect of propranolol may explain, at least partly, its depression effects on the cardiac functions of the animal.
Adenosine Diphosphate↗
Surface marker analysis of acute lymphocytic leukaemia in Taiwan, Republic of China.
Acute lymphocytic leukaemia (ALL) is heterogeneous in clinical characteristics and immunological properties. Standard surface marker analysis has enabled us to subclassify 121 cases of ALL into four subtypes, i.e. T-ALL, common ALL, null ALL and B-ALL. We have also tried to correlate these subtypes with their clinical characteristics. Our patients had younger ages with a mean age of 13.75. A slight male predominance was observed. There were consistently higher incidences in northern Taiwan in each subtype, but no significant differences in incidences between rural and urban areas. Although there were high incidences of L1 type cell in each immunological subtype, there was no correlation between FAB classification and each subtype, nor did morphologic features relate to cellular origins. Clinical manifestations revealed significantly high incidence of CNS involvement and thymic mass in T-ALL. Hepatosplenomegaly was more common and complete remission rate was higher in children with ALL than in adults.
Adolescent↗
Mechanisms of verapamil-induced conduction block in anomalous atrioventricular bypass tracts.
Verapamil, a calcium channel blocking agent, has been demonstrated to have depressive effects on the atrioventricular (AV) node but not anomalous AV bypass tracts. Of 39 patients with AV reciprocating tachycardia utilizing left-sided bypass tracts for retrograde conduction, intravenous infusion of verapamil (0.15 mg/kg) terminated the tachycardia in 31 patients. Verapamil interrupted the tachycardia circuit by inducing retrograde conduction block in the bypass tract rather than the AV node in 5 of these 31 patients. Electrophysiologic studies in these five patients revealed that verapamil-induced conduction block in the bypass tract could be accounted for by two distinctly different mechanisms. In three patients, verapamil induced alternating slow and fast AV nodal conduction resulting in alternating long and short cycle lengths during the tachycardia; consequently, development of the Ashman phenomenon in the bypass tract terminated the tachycardia. In the remaining two patients, the bypass tract exhibited properties similar to those of the AV node; verapamil prolonged the effective refractory period of the bypass tract, thereby terminating the tachycardia. Thus, depending on the functional properties of the bypass tract, verapamil may interrupt an AV reciprocating tachycardia circuit by exerting either a direct or indirect depressive action on the bypass tract.
Adult↗
Echocardiographic study of cardiac abnormalities in families of patients with Marfan's syndrome.
Twelve patients (5 male and 7 female; mean age 17.7 +/- 12.3 years, range 5 to 42) with Marfan's syndrome and 48 of their first degree relatives (16 male and 22 female; mean age 29.8 +/- 17.3 years, range 4 to 60) were evaluated for cardiac abnormalities by echocardiography. Of the patients with Marfan's syndrome, aortic valve prolapse was present in 1, tricuspid valve prolapse in 4, mitral valve prolapse in 12 and aortic root dilation in 10. Of the 48 first degree relatives of these 12 patients, tricuspid valve prolapse was diagnosed in 3, mitral valve prolapse in 15 and aortic root dilation in 12; aortic valve prolapse was not observed in any of these subjects. Of the 60 persons studied in these 12 kindreds, 28 (47%) had cardiac involvement. Among the 28 with cardiac involvement, aortic valve prolapse was observed in 1 (3.5%), tricuspid valve prolapse in 7 (25%), mitral valve prolapse in 27 (96%) and aortic root dilation in 22 (79%). Mitral valve prolapse was also present in the seven subjects with tricuspid valve prolapse and one with aortic valve prolapse. In 32 of the 60 persons studied in the 12 families, at least one abnormality of the cardiac, skeletal or ophthalmologic system was observed. Nineteen subjects were younger than 18 years of age; all had cardiac involvement associated with Marfan's syndrome. The notably earlier presentation of cardiac involvement in young persons may be responsible for a shorter life span in this group.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Spontaneous echocardiographic contrast and hepatic congestion.
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Echocardiography↗
Electromechanical effects of caffeine in isolated human atrial fibres.
Effects of caffeine on the action potential and contractile force of human atrial fibres obtained at cardiac surgery were studied with standard microelectrode technique. In 4 mmol . litre-1 [K]o, the only significant action produced by 0.3 to 3 mmol . litre-1 caffeine on the electro-mechanical activity of relatively normal atrial fibres was a slight shortening of the action potential duration at 50% repolarisation. When the fibres were depolarised in 27 mmol . litre-1 [K]o or in atrial fibres showing slow responses in 4 mmol . litre-1 [K]o, however, caffeine could increase the upstroke of slow response and the force. In 18% of atrial fibres showing slow responses in 4 mmol . litre-1 [K]o, caffeine induced spontaneous discharges and potentiated afterdepolarisations. The positive inotropic and the arrhythmogenic effects of caffeine could be diminished by pretreating the fibres with propranolol or Ca antagonists (diltiazem and verapamil). In fibres beating spontaneously in normal [K]o, caffeine accelerated spontaneous rhythms initially and then depressed them. Propranolol potentiated the later depression but did not block the initial acceleration. The results suggest that caffeine increases the transmembrane Ca influx and enhances the release of Ca from the intracellular stores in human atrial fibres. As a consequence, caffeine could induce arrhythmias in atria from certain individuals.
Action Potentials↗
Immunoprophylaxis of infection with hepatitis B virus in infants born to hepatitis B surface antigen-positive carrier mothers.
Infants born to carrier mothers positive for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) received 5 micrograms of hepatitis B virus (HBV) vaccine on four occasions. Group 1 received vaccine only, group 2 received vaccine plus hepatitis B immune globulin (HBIG) at birth, and group 3 received vaccine plus HBIG at birth and at one month. Infants born to HBeAg-positive mothers (group 4) received a reduced dose of vaccine (2.5 micrograms) on three occasions as well as HBIG at birth. As compared with 78.4% of the control group (infants whose parents refused vaccination) who became chronic HBV carriers at the age of 14 months, the protective efficacy rate of vaccination was 75.3% in group 1,85.5% in group 2,89.7% in group 3, and 87.2% in group 4. HBV vaccine (5 micrograms) was also given to infants born to HBsAg-positive, HBeAg-negative mothers on four on four occasions. The antibody response to HBsAg in vaccine recipients was 12% after the first dose, 44% after the second dose, and 75% and 100% at six months and 1.5 years of age, respectively.
Adult↗
Calcium antagonists stimulate sperm motility in ejaculated human semen.
Three calcium antagonists, diltiazem, flunarizine and verapamil stimulated human sperm motility in vitro. Among them, diltiazem induced the largest amplitude of motility increase. The concentration-response curve of diltiazem was similar in shape to those of calcium chelators. EGTA, a calcium chelator, potentiated the stimulatory effect of diltiazem while A23187, a calcium ionophore, antagonized it. These observations supported our previous hypothesis that an increased concentration of calcium ion was detrimental to human sperm motility. Whether calcium antagonists could be used in the treatment of subfertile patients awaits further investigation.
Calcimycin↗
Involvement of calcium in the caffeine stimulation of human sperm motility.
The shape of the concentration-response curve and the amplitude of maximal motility increase for the stimulatory effect of caffeine on human sperm motility were similar to those of EGTA, a calcium chelator, and lanthanum chloride, a calcium entry blocker. On the other hand, the maximal motility stimulation induced by dibutyryl cyclic AMP was similar to that induced by trifluoperazine, a calmodulin antagonist. The antagonism of A23187 on the motility-stimulating effect of EGTA and caffeine was competitive in nature, while that on cyclic AMP was non-competitive. We proposed that there could be two mechanisms for caffeine to stimulate sperm motility: at higher concentrations, caffeine modified calcium translocation; at lower concentrations, caffeine increased cyclic AMP level. The importance of calcium in the regulation of human sperm motility was reconfirmed in this study.
Bucladesine↗
Screening the in vitro sperm-immobilizing effect of some anticancer drugs.
The in vitro sperm-immobilizing effect of seven anticancer agents, namely cyclophosphamide, 5-fluorouracil, cytarabine, mitomycin-C, 6-mercaptopurine, doxorubicin and vinblastine were screened with a transmembrane migration method. Only doxorubicin and vinblastine inhibited human sperm motility. Because colchicine, a microtubular inhibitor, had no sperm-immobilizing effect, we suggest that the sperm membrane is the site of action of these two anticancer drugs to inhibit human sperm motility.
Antineoplastic Agents↗
Activities of transport adenosine triphosphatases in erythrocyte membranes of healthy and hypertensive subjects.
The Na+, K+-ATPase activity in the erythrocyte membrane was measured in 25 untreated essential hypertensive patients and 25 age-matched healthy normotensive subjects. In addition, the Ca2+, Mg2+-ATPase activity was measured in 20 hypertensive and 25 age-matched normotensive subjects. The Na+, K+-ATPase activity of healthy Chinese measured in this study was similar to the data reported in a Dutch study. We therefore could not support a theory which speculated an ethnic influence on Na+, K+-ATPase activity. Both Na+, K+-ATPase and Ca2+, Mg2+-ATPase activities were slightly lower in hypertensive patients as compared with those in normotensive subjects, but the differences were not statistically significant. We concluded that the transport ATPase activities were not impaired in the erythrocyte membranes of hypertensive patients.
Adult↗
Suppressive effects of oral ketotifen on skin responses to histamine, codeine, and allergen skin tests.
Nine healthy subjects were given 1 mg ketotifen orally and were skin tested with histamine (4, 10, and 20 micrograms/mL), codeine (0.001%, 0.01%, and 0.1%) and normal saline at varying time intervals up to 96 hours. Seven subjects allergic to tree and dust allergens were studied in the same way and were skin tested with both allergens. The suppression of skin responses in both studies occurred maximally between 4 and 24 hours, and did not disappear until 72 hours. The control subjects not taking ketotifen did not show any suppression. These results suggest that oral ketotifen should be withheld for 72 hours prior to immediate type hypersensitivity skin tests.
Administration, Oral↗
Combined passive and active immunization for interruption of perinatal transmission of hepatitis B virus in Taiwan.
We attempted a clinical trial to interrupt transmission of hepatitis B virus (HBV) infection from hepatitis B surface antigen (HBsAg) positive and hepatitis Be antigen (HBsAg) positive mothers to their infants in Taiwan. Screening of 5,595 pregnant women revealed that 856 (15.3%) were HBsAg positive. Three hundred and sixty-one (42.2%) of the HBsAg positive pregnant women were HBeAg positive. Infants born to HBsAg and HBeAg positive mothers were randomized into 3 groups to receive the HBV vaccine alone or combined with hepatitis B immune globulin (HBIG). HGV vaccine was given at 2, 6, and 10 weeks after birth. Group I received HBV vaccine alone while Group II received HBV vaccine in combination with HBIG at birth and group III received HBV vaccine plus HBIG at birth and again at one month old. Group IV constituted the control group when their parents refused vaccination. At 6 months of age, the HBV carrier rate was 23.7% (9/38) in Group I, 11.1% (4/36) in Group II, and 5.3% (2/38) in Group III infants. Compared with 90% of infants who became HBV carriers in the control group (Group IV), the efficacy of HBV vaccination in preventing HBV infection among these high risk infants at the 6th month was 73.7% in Group I, 87.7% in Group II, and 94.1% in Group III. The antibody to HBsAg (anti-HBs) positivity rate in sera of Group I, II, III infants at 6 months of age was 79.0%, 88.9% and 94.7%, respectively. These initial results indicate that combined passive and active immunization is efficacious in interrupting perinatal transmission of HBV infection.
Adult↗
Adult T-cell leukemia. First case reported in Taiwan.
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Adult↗
Establishment and characterization of a new human lymphoma-derived cell line--HBL-2.
A new human B-cell lymphoma-derived cell line, designated HBL-2, was established from peripheral blood of a 17-year-old male during terminal leukemic phase. HBL-2 cells were single cell suspensions when cultured in RPMI 1640 with 10% fetal calf serum promoting a doubling time of about 20 hours. Cell marker studies revealed Ia and surface immunoglobulin positive, cytoplasmic immunoglobulin and Epstein-Barr nuclear antigen negative. Chromosome analysis showed a male aneuploid karyotype with 14q+ and other abnormal markers. Under electron microscopy, the cells exhibited clear nucleoli, fine chromatin, and were in a primary differentiated state. The establishment of HBL-2 cell line provides a powerful tool in studying the oncogenesis of B-cell malignancy.
Animals↗
Lack of influence of aluminum hydroxide on the bioavailability and beta-adrenoceptor blocking activity of propranolol.
Plasma concentrations of propranolol and the changes of exercise induced heart rate were determined in 6 healthy subjects. An amount of 40 mg of propranolol was given alone or in combination with 30 ml of aluminum hydroxide gel. Neither the bioavailability nor the beta-adrenoceptor blocking activity of propranolol was significantly changed by concurrent administration of aluminum hydroxide gel. There is no need to increase the propranolol dose when aluminum hydroxide gel is administered concurrently.
Adult↗
Calcium ion is the key regulator of human sperm function.
Calcium ions have an apparently paradoxical effect on sperm motility. In the epididymis, calcium ions stimulate immature sperm, whereas, in ejaculated semen, calcium ions inhibit sperm motility. Maturation processes change the response of sperm to calcium ions. Calcium binding substances and calcium transport inhibitors are secreted by male accessory sexual organs and mixed with sperm during ejaculation. In the female genital tract sperm acquire full capacity of fertilise the ovum. Calcium binding substances and calcium transport inhibitors are removed during the process known as capacitation. Finally, calcium ions trigger the acrosome reaction and facilitate sperm penetration into the ovum.
Acrosome↗