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Biomedical subjects

D J Wang

Publications and source records attributed to D J Wang.

At least 73 records · Page 4Linked to original sources
PubMed1990

[Drug interaction between digoxin and bisacodyl].

Digoxin is one of the inotropic agents commonly used to improve cardiac performance in patients with congestive heart failure and to control ventricular response in atrial fibrillation and other supraventricular tachycardias. Bisacodyl (dulcolax), a stimulant laxative, is also commonly prescribed to prevent straining at stool or constipation in these patients. Therapeutic monitoring of digoxin is helpful in the evaluation of clinical response and intoxication of digoxin. For the convenience of serum level measurement, digoxin is usually administered at night before sleep to allow ample time for tissue distribution and then blood sampling the next morning. Concomitant use of these drugs may increase the likelihood of drug interaction. Eleven healthy volunteers, aged 22-26, were studied within 35 days accordingly in four phases. The serum digoxin concentration (SDC) in phase 2 (digoxin and bisacodyl together) showed a significant decrease as compared with phase 1 (digoxin alone) (0.58 +/- 0.03 vs. 0.66 +/- 0.03 ng/ml, M +/- SE, p less than 0.05). The percentage of SDC changes was down to -11.7 +/- 5.4%. Phase 4 (digoxin taken 2 hours before bisacodyl) showed an increase in SDC in comparison with phase 3 (digoxin alone) but was not statistically significant (0.65 +/- 0.03 vs. 0.62 +/- 0.03 ng/ml, M +/- SE, p greater than 0.05). The average frequency of diarrhea was 3.5 times in the first day of phase 2 and 2.7 times in the first day of phase 4. We conclude that in volunteers bisacodyl interacts with digoxin resulting in reduction of the SDC. Interference of the absorption is the most likely mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Detection of dysfunctioning mitral prosthetic regurgitation: transesophageal echocardiography in comparison with transthoracic echocardiography and angiography.

Transesophageal echocardiography has been increasingly used in addition to the transthoracic approach. It not only allows an unobstructed window for viewing the left atrium, but also provides high-quality imaging to improve diagnosis of prosthetic valve dysfunction. To determine the value of transesophageal echocardiography in detection of dysfunctioning mitral prosthetic regurgitation, 11 patients clinically suspected of dysfunctioning mitral prosthesis were studies by transthoracic, transesophageal echocardiography and was documented by a left ventricular angiography. There were 7 biological tissue valves and 4 metallic Bjork-Shiley valves. Compared with a left ventricular angiography, the transthoracic approach to 8 patients made an underestimation of the grade of regurgitation. The angiographic grading confirmed the transesophageal approach in all patients except one who was graded as mild regurgitation by left ventricular angiography, moderate regurgitation by transesophageal echocardiography, but no regurgitation by transthoracic echocardiography. Our results indicated that in patients with suspected mitral prosthetic dysfunction, a transesophageal echocardiography is more sensitive than a transthoracic echocardiography in detecting mitral regurgitation.

Adult↗
PubMed1990

Features of head injury in a developing country--Taiwan (1977-1987).

Certain features of head-injured patients admitted to the Chang Gung Memorial Hospital in Taiwan during the period 1977 to 1987 were reviewed. The most common causes of injury were motorcycle accidents (56.3%) and street accidents with pedestrian injury (29.47%). The age groups with the greatest incidence of injury were aged 16-20 years, 21-25 years, and 25-30 years. The pedestrian group involving the highest incidence of injury was less than 10 years of age. Overall mortality was 17.26%. The injured pedestrian group had the highest mortality (19.1%). Initial clinical assessment was recorded using the Glasgow Coma Scale. Head-injured patients with a GCS less than 8 had a mortality in the injured pedestrian group of 46%, whereas the mortality rate in the motorcycle accident group was 41%. Additional features studied were time of occurrence of injury and pattern of injury. Information gathered from this study would suggest the need to establish a Head Injury Prevention Program in Taiwan. This of course implies major cooperation among the providers of health care delivery, the medical profession, legislators, and the government at all levels.

Adolescent↗
PubMed1989

Three types of atrioventricular reciprocating tachycardia using bilateral accessory pathways in a patient with Wolff-Parkinson-White syndrome.

Electrophysiologic studies were performed on a patient with Wolff-Parkinson-White syndrome and recurrent supraventricular tachycardia. Bilateral accessory pathways capable of antegrade and retrograde conduction and three different types of atrioventricular (AV) reciprocating tachycardia were demonstrated. One type of narrow QRS tachycardia used the normal AV pathway for antegrade conduction and the left-sided accessory pathway for retrograde conduction. Two types of wide QRS tachycardia (one with right bundle branch block and one with left bundle branch block) used both accessory pathways for antegrade and retrograde conduction, respectively, and were independent of the normal AV pathway. The data showed that bilateral accessory pathways have different electrophysiologic properties and participate in three different types of AV reciprocating tachycardia.

Administration, Oral↗
PubMed1989

Prophylactic anticonvulsants for prevention of immediate and early postcraniotomy seizures.

Phenytoin (15 mg/kg) was administered intravenously to 189 patients shortly before their intracranial, supratentorial surgery was completed. Intravenous phenytoin of 5-6 mg/kg/day in three divided doses was administered daily for the first 3 postoperative days. Therapeutic serum levels (10-20 micrograms/mL) were achieved in 113 (59.8%) patients. An equally constituted, randomized control group of 185 patients received a placebo under identical conditions. The group receiving phenytoin had only one immediate and two early postoperative seizures. The 185 controls had four immediate and nine early postoperative seizures. None of the follow-up computed tomography scans of the patients with seizures showed postoperative hematoma. One patient had a significant tension pneumocranium, a possible cause of postoperative seizures. To avoid a decrease in the serum anticonvulsant level due to intraoperative blood loss, it is suggested that for patients who need an urgent or emergent craniotomy, prophylatic anticonvulsant medication should be given at least 20 minutes before completion of wound closure.

Adult↗
PubMed1989

Extracellular ATP is a mitogen for 3T3, 3T6, and A431 cells and acts synergistically with other growth factors.

Extracellular ATP in concentrations of 5-50 microM displayed very little mitogenic activity by itself but it caused synergistic stimulation of [3H]thymidine incorporation in the presence of phorbol 12-tetradecanoate 13-acetate, epidermal growth factor, platelet-derived growth factor, insulin, adenosine, or 5'-(N-ethyl)carboxamidoadenosine. Cultures of Swiss 3T3, Swiss 3T6, A431, DDT1-MF2, and HFF cells were used. The percent of cell nuclei labeled with [3H]thymidine and cell number were also increased. ADP was equally mitogenic, while UTP and ITP were much less active. The effect of ATP was not due to hydrolysis by ectoenzymes to form adenosine, a known growth factor. Thus, the nonhydrolyzable analogue adenosine 5'-[beta, gamma-imido]triphosphate was mitogenic. In addition, it was found that ATP showed synergism in 3T6 and 3T3 cells when present for only the first hour of an incorporation assay, during which time no significant hydrolysis occurred. Furthermore, prolonged preincubation of cells with ATP reduced the mitogenic response to ATP but not to adenosine; preincubation with adenosine or N6-(R-phenylisopropyl)adenosine had the reverse effect. Finally, the effect of adenosine, but not of ATP, was inhibited by aminophylline. We conclude that extracellular ATP is a mitogen that interacts with P2 purinoceptors on the plasma membrane.

Adenosine↗
PubMed1989

Clinical experience with percutaneous intra-aortic balloon pumping in cardiogenic shock complicating acute myocardial infarction.

From July 1984 to December 1987, intra-aortic balloon pumping (IABP) was attempted percutaneously to 22 patients at the ages of 37-78 with cardiogenic shock or medically refractory heart failure complicating acute myocardial infarction (CS/MRHF-AMI). There was only one failure because of severe bilateral iliofemoral atherosclerosis. Of the 21 patients undergoing IABP, 17 were in cardiogenic shock and 13 of them showed reversal of shock syndrome after 10 to 48 hours of IABP. Cardiac index increased from 1.91 +/- 0.43 to 2.45 +/- 0.43 L/min/M2 (P less than 0.005), spontaneous systolic arterial pressure rose from 79 +/- 10 to 114 +/- 19 mmHg (P = 0.0001), heart rate dropped from 111 +/- 26 to 85 +/- 13 beats/min (P = 0.0001), pulmonary artery wedge pressure decreased from 29 +/- 5 to 16 +/- 3 mmHg (P = 0.0001), and urine output increased from 7 +/- 10 to 79 +/- 22 ml/h (P = 0.0001). Twelve patients, including 4 shock-free, were subsequently weaned from balloon assistance. Of these patients, 8 (5 shock and 3 nonshock) were discharged from the hospital and followed-up for a mean period of 23 months (4 to 38 months). Of the surviving patients, 4 underwent surgical reperfusion and/or infarctectomy during balloon support (n = 1) or after weaning from IABP (n = 3). All of the 10 patients who underwent coronary angiogram were found a severe left anterior descending artery lesion. The main complication was leg ischemia, which was observed in 7 patients: 3 needed removal or replacement of balloon catheter and one required surgical removal of the thrombus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Diagnostic value of maximal treadmill exercise electrocardiogram in predicting coronary artery disease for asymptomatic Chinese male subjects.

The value of maximal treadmill exercise electrocardiogram (TEE) in predicting coronary artery disease was evaluated in a consecutive series of 168 asymptomatic Chinese males, aged 41 to 57 years (mean 53) during annual physical examinations. Their resting electrocardiograms (ECGs) showed no abnormal Q-waves. The end-point of TEE achieved the age-predicted maximal heart rate, and no subjects had classic angina pectoris during or after TEE. Thirty-five subjects had positive electrocardiographic changes defined as reversible horizontal or downsloping ST-segment depression greater than or equal to 1.0 mv which lasted greater than or equal to 0.08 sec. Exercise thallium-201 (T1-201) myocardial imaging was performed on all 35 subjects with positive TEE; 30 subjects (86%) demonstrated normal and 5 abnormal scintigrams. Sixteen of the 30 cases with normal T1-201 scans underwent coronary arteriography, of which 14 showed normal arteriograms and two showed a less than 49% stenosis of the luminal diameter in one major artery. Of the 5 cases with abnormal scintigrams, 4 were found to have greater than 50% stenoses in at least one major artery, and only one case had a less than 49% stenosis of the right coronary artery. We concluded that TEE alone for asymptomatic individuals provided limited value in diagnosing significant coronary artery disease, especially in areas of low prevalence.

Adult↗
PubMed1988

Closed-loop analysis of the reflex function in orthostatic hypotension.

The arterial baroreceptors and cardiopulmonary receptors are important for the control of blood pressure during orthostatic stress. We assessed the baroreflex loop gain of arterial pressure compensation to orthostatic hypotension in pentobarbital-anesthetized and gallamine-paralyzed dogs subjected to 45 degrees and 90 degrees head-up tilt. The orthostatic hypotension before and after sinus denervation and cervical vagotomy was designated as D' and D, respectively. The loop gain (G) was calculated using closed-loop analysis: G = (D/D')-1. In 10 dogs, the D', D and G were 17.2 +/- 2.2 (mean +/- SE) mmHg, 64.2 +/- 4.4 mmHg and 2.73 +/- 0.26, respectively in 45 degrees tilt; and 30.6 +/- 3.2 mmHg, 80.7 +/- 5.2 mmHg and 1.64 +/- 0.24, respectively in 90 degrees tilt. Atropine sulfate (0.5 mg/kg, i.v.) eliminated the reflex tachycardia, but did not affect the SAP change during the head-up tilt. The effects of cervical vagotomy on the orthostatic hypotension were thus attributed to interruption of the aortic nerves and vagal afferents. The data provide a quantitative measure of the baroreflex function during the orthostatic stress. The loop gain is not a constant function because the value is significantly less in 90 degrees than in 45 degrees tilt (P less than 0.05). The nonlinear control system implies that the baroreflex compensation became less efficient in the face of a greater blood pressure perturbation.

Animals↗
PubMed1987

Demonstration of persistent left superior vena cava by first pass radionuclide angiography.

A case of the left superior vena cava draining to the coronary sinus without associated intracardiac shunt was initially demonstrated by first pass radionuclide angiography. The patient had atypical chest pain for 8 years, and had sick sinus syndrome with a long cardiac pause. Cardiac catheterization confirmed this diagnosis, and a transvenous pacemaker was successfully implanted through the left superior vena cava.

Aged↗
PubMed1987

Demonstration of intracardiac tumor and its associated hemodynamic derangement by radionuclide angiography.

A case of malignant lymphoma primarily involving the heart is reported for the first time in which the tumor per se and its accompanying hemodynamic abnormalities were demonstrated by radionuclide angiography (RNA). The patient had severe and progressive failure of the right side of the heart of obscure origin. The tumor was pathologically proven to have involvement of the pericardium, right atrium, and right ventricle, causing significant tricuspid and pulmonic obstruction.

Heart Failure↗
PubMed1986

A giant congenital aneurysm of the right coronary artery.

A young woman with shortness of breath was diagnosed preoperatively as having a coronary artery aneurysm. The aneurysm originated from the right coronary artery and was extraordinarily large. The aneurysm was excised successfully under extracorporeal circulation.

Adult↗