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Biomedical subjects

K Y Wang

Publications and source records attributed to K Y Wang.

At least 19 recordsLinked to original sources
PubMed1992

Transesophageal echocardiography in adults with a continuous precordial murmur.

In order to assess the ability of echocardiography in the detection of intracardiac and extracardiac shunts, we studied 11 patients (aged 22-64 yr) with a continuous precordial murmur using transthoracic and transesophageal echocardiography, and correlated the results with the subsequent angiographic and surgical findings. We found that only in 5 of 6 patients with a patent arterial duct could the continuous flow pattern be detected in pulmonary artery using transthoracic echocardiography, whereas it could be readily and accurately identified by transesophageal echocardiography in all patients. The diameters of the patent arterial duct were also measured and found to be in good correlation with subsequent surgical findings (r = 0.98, p less than 0.05). In 2 patients with a ruptured aneurysm of sinus of Valsalva which originated from the right coronary sinus and perforated into the right ventricle, transesophageal echocardiography gave a better image than transthoracic echocardiography. In 2 patients with coronary artery fistula, the origin and site of drainage of the coronary artery could be imaged using transesophageal echocardiography, but the course of coronary artery fistula was more easily detected by transthoracic echocardiography. In one patient with aortopulmonary window, the defect between ascending aorta and main pulmonary artery could readily be imaged by transesophageal echocardiography. We therefore recommend transesophageal echocardiography when evaluating patients with precordial continuous murmur in whom intracardiac and extracardiac shunts or defects are suspected.

Adult↗
PubMed1992

Pronounced differences between native Chinese and Swedish populations in the polymorphic hydroxylations of debrisoquin and S-mephenytoin.

The frequency of poor metabolizers of debrisoquin was low and similar in four different native Chinese nationalities. In a total sample of 695 Chinese subjects, only seven (1.01%) had a urinary ratio between debrisoquin and 4-hydroxydebrisoquin greater than 12.6, which is the antimode between poor metabolizers and extensive metabolizers in white populations. This is significantly lower than the 6.82% found in 1011 white Swedish healthy subjects (p less than 0.0001). Admixture analysis indicated the occurrence of two distributions within extensive metabolizers among both Chinese and white subjects. The mean of the distribution of metabolic ratios among Chinese extensive metabolizers was shifted toward higher values compared with Swedish extensive metabolizers (p less than 0.01). The frequency of poor metabolizers of S-mephenytoin was higher in 137 Chinese (14.6%) than in 488 Swedish (3.3%) subjects (p less than 0.0001). Our findings imply that drugs metabolized by these two polymorphic hydroxylases should be prescribed in different dosages to Chinese and white subjects.

China↗
PubMed1992

Evaluation of a 20-MHz ultrasound transducer used in diagnosing porcine small bowl ischemia.

The authors have previously demonstrated the ability of an 8.5-MHz linear array to detect moderate or severe intestinal ischemia in a porcine model. This study compares the ability of the 8.5-MHz linear array with a prototype miniature 20-MHz ultrasound (US) imaging probe in detecting small bowel ischemia. Five piglets were studied in which vascular clamps were applied to isolated jejunal pedicles, then released sequentially at hourly intervals to induce ischemia from 0 to 6 hours. After 24 hours of reperfusion, the tissue was removed and examined with both the 8.5-MHz linear array and the 20-MHz probe. A histologic examination also was done. The acoustical criteria used for interpretation were presence or absence of folds, number of echo layers, relative thickness of layers and homogeneity and continuity of layers. The 8.5-MHz system predicted the duration of ischemia with a kappa value of 0.66 +/- 0.03, whereas the 20-MHz system had a kappa value of 0.49 +/- 0.03. Both systems were able to distinguish normal or mild ischemia from moderate or severe ischemia with sensitivity and specificity rates of at least 94%. Both 8.5- and 20-MHz US systems detected intestinal ischemia in vitro. Further studies are indicated to determine the ideal frequency and design for a US system that can be used clinically.

Animals↗
PubMed1992

Nondisplaced fractures of the greater tuberosity of the humerus: sonographic detection.

In this retrospective study, the sonographic appearance of fracture of the greater tuberosity of the humerus was evaluated in 17 men and 14 women aged 20-69 years with acute, semiacute, or remote shoulder trauma in whom results of rotator cuff sonography had suggested the diagnosis of such a fracture. Clinical data, radiologic reports, sonograms, and initial plain radiographs of the shoulder were analyzed; clinical follow-up information was assessed in 22 patients. Sonography showed discontinuity and irregularity of the humeral cortex in all patients. In 25 patients (81%), displaced fracture fragments could be seen. Sonographic findings were suggestive of, but not specific for, fracture. Cortical abnormalities of the humerus were identified without modification of standard scanning protocols. A humeral fracture was confirmed with radiography in 24 patients; in 10 of them, the fracture had been missed initially on plain radiographs. It is concluded that, in evaluation of soft tissues in shoulder trauma, sonography may define rotator cuff abnormalities and occasionally help in detection of occult humeral fractures.

Adult↗
PubMed1992

Appendiceal US scans: histologic correlation.

High-resolution in vitro ultrasonography (US) of 20 surgical appendiceal specimens was performed to compare appearances of appendiceal tissue at US with corresponding histologic features. With an articulated-arm system and micropositioner, precise spatial correlation was achieved. As elsewhere in the gastrointestinal tract, five distinct echo layers were observed. Normal and inflamed specimens demonstrated these layers, but the architecture became disorganized and indistinct in cases of appendicitis. Three measurements were made for each specimen: (a) overall cross-sectional diameter, including the lumen, (b) thickness of the submucosal echo layer, and (c) the combined thickness of both walls, excluding the lumen. For the inflamed specimens, a substantial increase in the thickness of the summed wall measurements was found. Wall US appearance alone may be misleading in differentiation of normal and abnormal appendices.

Adolescent↗
PubMed1992

Recent advances in primary palate and midface morphogenesis research.

During the sixth week of human development, the primary palate develops as facial prominences enlarge around the nasal pits to form the premaxillary region. Growth of craniofacial components changes facial morphology and affects the extent of contact between the facial prominences. Our recent studies have focused on developing methods to analyze growth of the primary palate and the craniofacial complex to define morphological phases of normal development and to determine alterations leading to cleft lip malformation. Analysis of human embryos in the Carnegie Embryology Collection and mouse embryos of cleft lip and noncleft strains showed that human and mouse embryos have similar phases of primary palate development: first, an epithelial seam, the nasal fin, forms; then a mesenchymal bridge develops through the nasal fin and enlarges rapidly. A robust mesenchymal bridge must form between the facial prominences before advancing midfacial growth patterns tend to separate the facial components as the medial nasal region narrows and elongates, the nasal pits narrow, and the primary choanae (posterior nares) open posterior to the primary palate. In mouse strains with cleft lip gene, maxillary growth, nasal fin formation, and mesenchymal replacement of the nasal fin were all delayed compared with noncleft strains of mice. Successful primary palate formation involves a sequence of local cellular events that are closely timed with spatial changes associated with craniofacial growth that must occur within a critical developmental period.

Animals↗
PubMed1992

Pericardiocentesis: a 20 patients study.

Emergency pericardiocentesis, guided by a two-dimensional echocardiography, was performed on twenty patients with symptomatic pericardial effusion of various types and causes. There were fourteen men and six women. The underlying causes were: primary lung cancer (6 cases), metastatic cardiac tumors (3 cases), tuberculosis (4 cases), complicated interventional procedures with cardiac chamber or vessel perforations (2 cases), dissecting aortic aneurysm (1 case), systemic lupus erythematous (1 case), idiopathic pericarditis (1 case), bacterial pericarditis (1 case), and myxedema heart disease (1 case). Seventeen cases were performed through the left xipho-sternal approach and 3 cases through the apical approach. None of the patients died as a result of these procedures. A two-dimensional echocardiogram is useful in diagnosing cardiac tamponade as well as in guiding pericardiocentesis, and obtaines highly positive results (20/20). The positive rate of pericardial fluid cytology for malignant cells was 89% (8/9), however, pericardial fluid cultures or direct smear for tuberculosis were negative (0/4). In cancer patients, the mean survival time following pericardiocentesis was 4.2 months (range, 1-7.8 months). We concluded that neoplastic involvement of the pericardium is the most frequent cause of symptomatic pericardial effusion. Pericardiocentesis assisted by a two-dimensional echocardiogram is safe and easy. In addition, pericarditis caused by TB is still significant and must be considered in every case in our nation.

Adult↗
PubMed1992

[Facilitatory effect of Pinellia ternata lectin on quantal release of acetylcholine from nerve terminals].

Pinellia ternata lectin (PTL) extracted from the rhizome of Pinellia ternata Briet by porcine thyroglobulin-Sepharose 4B column exhibits hemagglutination activity and carbohydrate binding specificity for mannan. Here we reported the effects of PTL on the resting membrane potential of muscle fiber and on the release of acetylcholine (ACh) from the motor nerve terminals in the phrenic nerve diaphragm preparations of mice. The results showed that PTL increased the frequency of miniature end-plate potential (MEPP). In 30 min after the treatment of the preparation with lectin 100 micrograms.ml-1, the frequency of MEPP reached 20 times higher than that of the control. Addition of mannan 1 mg.ml-1 restored the raised discharge of MEPP to its control level immediately. Similar to the effect of PTL on MEPP frequency, the amplitude and mean quantal content of end-plate potential also increased after PTL. At 100 micrograms.ml-1, the lectin depolarized the muscle membrane slightly, while at 10 micrograms.ml-1 no effect on the membrane potential was found. These results were interpreted as the intracellular Ca2+ elevation due to a permeability increase of the nerve terminal to ions after PTL.

Acetylcholine↗
PubMed1992

[Cation channels formed in lipid bilayer by Pinellia ternata lectin].

Pinellia ternata lectin (PTL), a protein exhibiting hemagglutination activity and carbohydrate binding specificity to mannan was purified from rhizome of Pinellia ternata. In this work the actions of PTL on artificial lipid bilayer were investigated by means of the two-compartment system of Mueller and Rudin. The lipid bilayer with resistance more than 10G omega was formed by a solution of lecithin and cholesterol (20 mg/ml and 5 mg/ml respectively) in N-decane. The electrical properties of the lipid bilayer were investigated in voltage clamp mode. Several minutes after the addition of PTL (2 micrograms/ml) in one compartment the channel-like noise as well as a decrease of the resistance of the bilayer were observed. These actions were inhibited by mannan significantly. The resistance increase of the bilayer with PTL-channels could be observed from 2G omega to control level (greater than or equal to 10 G omega) immediately after addition of 40 micrograms/ml mannan. The discrete conduction steps were recorded at low concentration of PTL and at low holding potential. The predominant unit conductance was 35pS in symmetric KCl solution of 100 mmol/L. The selectivity of PTL-channel was estimated from Goldman-Hodgkin-Katz equation by measurement of the reversal potential in an asymmetrical salt solution. The results showed that PTL-channels were cation selective.

Cations↗
PubMed1991

Extrauterine findings of ectopic pregnancy of transvaginal US: importance of echogenic fluid.

Transvaginal ultrasound (US) studies of 232 consecutive patients with positive serum pregnancy tests who were considered to be at risk for ectopic pregnancy were prospectively evaluated to determine the significance of various extrauterine findings, including echogenic fluid in the cul-de-sac. All patients were found to have a surgically proved ectopic gestation (group 1, 68 patients [29.3%]), reliable evidence of intrauterine pregnancy at initial transvaginal US (group 2, 83 patients [35.8%]), or no evidence of pregnancy at initial transvaginal US, but subsequent proof of an intrauterine pregnancy (group 3, 81 patients [34.9%]). Adnexal findings were demonstrated in 45 (66%) group 1 patients, including a living extrauterine embryo in 10 (15%), an extrauterine gestational sac in 21 (31%), and an adnexal mass in 14 (21%). Intraperitoneal fluid was detected in 43 (63%) group 1 patients and in 81 (31%) group 3 patients. Echogenic fluid was the only abnormal finding at US in 10 (15%) group 1 patients and added confidence to the diagnosis of ectopic pregnancy in many others. Echogenic fluid correlated with hemoperitoneum at the time of surgery. The presence of echogenic fluid indicates a high risk for ectopic pregnancy in women referred with this clinical indication.

Female↗
PubMed1991

Assessment of normal and abnormal erectile function: color Doppler flow sonography versus conventional techniques.

The penile arteries were studied with color Doppler flow sonography in 10 subjects with normal and 39 patients with abnormal erectile function. The relationships of systolic and diastolic velocities to spectral waveform changes in the penile arteries in response to tumescence were studied before and after intracorporal injection of vasoactive medications that induce erection. In normal subjects, a characteristic spectral waveform pattern corresponded to increasing intracorporal pressure. Patients with abnormal arterial inflow and/or abnormal venous sinusoidal leakage demonstrated deviation from the patterns noted in normal subjects. Patients with abnormal arterial inflow had lower mean peak systolic velocities than normal subjects. Patients with severe venous sinusoidal incompetence had an arrest of waveform progression with evolution to but not beyond phases 1 or 2 (diastolic flow remained positive). Patients with abnormal arterial inflow and abnormal venous sinusoidal outflow had waveform changes that reflected both processes. Systolic/diastolic velocity and waveform relationships can be used to define the integrity of both the cavernosal artery inflow and venous sinusoidal outflow occlusion mechanisms.

Adult↗
PubMed1991

Repairs of the rotator cuff. Correlation of functional results with integrity of the cuff.

We evaluated the results of 105 operative repairs of tears of the rotator cuff of the shoulder in eighty-nine patients at an average of five years postoperatively. We correlated the functional result with the integrity of the cuff, as determined by ultrasonography. Eighty per cent of the repairs of a tear involving only the supraspinatus tendon were intact at the time of the most recent follow-up, while more than 50 per cent of the repairs of a tear involving more than the supraspinatus tendon had a recurrent defect. Older patients and patients in whom a larger tear had been repaired had a greater prevalence of recurrent defects. At the time of the most recent follow-up, most of the patients were more comfortable and were satisfied with the result of the repair, even when they had sonographic evidence of a recurrent defect. The shoulders in which the repaired cuff was intact at the time of follow-up had better function during activities of daily living and a better range of active flexion (129 +/- 20 degrees compared with 71 +/- 41 degrees) compared with the shoulders that had a large recurrent defect. Similar correlations were noted for the range of active external and internal rotation and for strength of flexion, abduction, and internal rotation. In the shoulders in which the cuff was not intact, the degree of functional loss was related to the size of the recurrent defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Study on the frequency distribution of debrisoquine hydroxylation deficiency in Chinese healthy Zang and Wei volunteers].

The metabolic ratio of debrisoquine hydroxylation (MR) determined as the ratio of debrisoquine over 4-OH-debrisoquine in 8 h urine after a single oral dose of DB (10 mg) in unrelated Chinese Zang and Wei volunteers was studied by using gas chromatography. The MR of 132 healthy Chinese Zang subjects ranged from 0.20 to 34.32, and that of 158 healthy Chinese Wei subjects ranged from 0.13 to 29.73. Two phenotypes were apparent in the frequency distribution histograms with an antimode at log MR = 1.10 (MR = 12.6). Two subjects were therefore identified as poor metabolizers (PMs) of DB in 132 Zang volunteers (the frequency of PMs was found to be 1.52%), and only one in 158 Wei volunteers (0.63%). Neither sex nor smoking habit affected the DB hydroxylation (P greater than 0.2). The recoveries of DB and 4-OH-DB in Zang volunteers were 19.83 +/- 10.99 and 11.57 +/- 7.04%, and in Wei volunteers they were 22.74 +/- 14.41 and 17.77 +/- 10.82%, respectively.

Adolescent↗
PubMed1990

Diagnosis of inflammatory bowel disease with ultrasound. An in vitro study.

Transabdominal ultrasound is frequently used to detect complications of inflammatory bowel disease. It has been proposed that ultrasound can distinguish between ulcerative colitis and Crohn's disease based on the degree of thickening and changes in the layered structure of the intestine. The authors evaluated the ability of ultrasound to distinguish between ulcerative colitis, Crohn's colitis, and normal colon by blindly comparing images made of resected colon specimens. The histologic interpretation of precisely the same area of tissue that was imaged was compared with the blinded image interpretation. Images from all 18 colitis specimens were correctly interpreted as being abnormal because of increased submucosal and overall wall thickness. Published ultrasound criteria for distinguishing between Crohn's disease and ulcerative colitis based on overall wall thickness and indistinctness of layers were inaccurate in 4 of 15 specimens and indeterminate in 3 cases. Ultrasound appears to be accurate in distinguishing normal from inflamed colon, but ultrasound findings alone should not be used to determine the cause of bowel inflammation.

Colitis, Ulcerative↗
PubMed1990

The fetal genitourinary tract.

Early recognition of fetal urinary tract anomalies may dramatically influence obstetric or neonatal management. Major fetal urinary abnormalities, including renal agenesis, obstructive lesions, and cystic disease, may be clinically silent but readily identified by sonography. Careful evaluation of the fetal genitourinary tract should therefore be an important component of the routine screening obstetric sonogram. Appreciation of normal sonographic appearances of the fetal genitourinary tract may facilitate early recognition of the abnormal fetus. Accurate prenatal sonographic characterization of a renal abnormality and evaluation of renal function are essential for fetal prognosis and management.

Constriction, Pathologic↗
PubMed1989

Doppler umbilical artery waveform indices--normal values from fourteen to forty-two weeks.

Normal values for Doppler waveform indices of the umbilical artery have been reported for gestational ages of 20 to 40 weeks in small numbers of normal patients. We evaluated 590 patients studies performed at 2-week intervals from 14 to 42 weeks' gestation on patients without medical or pregnancy complications. Readings were obtained during fetal quiet times (no fetal breathing or movements). Values for A (systolic) and B (diastolic) pressures were plotted as Pourcelot (A - B/A) and A/B ratios. Mean, SD, and 95% confidence limits were derived, and the skewness, kurtosis, and regression correlations were calculated. No diastolic flow was found in any pregnancy greater than 15 weeks' gestation (n = 25) or in 50% of the gestations between 15 to 17 weeks (n = 25). When diastolic pressure equals zero, the Pourcelot ratio value equals one and the A/B ratio approaches infinity and loses meaning. Recent work by Thompson et al. suggests that the Pourcelot ratio fits a normal distribution from 20 to 40 weeks' gestation and that the A/B ratio (which does not fit a normal curve) may be transformed to a normal distribution by conversion of the A/B ratio to 1/1 - Pourcelot ratio. Our data supports the normality of both indices from 18 to 42 weeks' gestation, but these assumptions are not applicable as the Pourcelot ratio approaches one or as the A/B ratio approaches infinity. Knowledge of normal umbilical flow ratios at gestational ages from 18 weeks may allow early detection and directed management of high-risk pregnancies.

Blood Flow Velocity↗
PubMed1989

Histologic correlates of gastrointestinal ultrasound images.

Endoscopic ultrasound imaging has potential for improving the diagnosis of gastrointestinal disease. However, the anatomic correlates of gastrointestinal ultrasound images have not been precisely defined. We have compared ultrasound images with the corresponding histologic sections of 81 specimens of resected and postmortem, normal and diseased gastrointestinal tissue. The five layers seen on ultrasound images of the normal gastrointestinal tract correspond to (1) superficial mucosa, (2) deep mucosa, (3) submucosa plus the acoustical interface between the submucosa and muscularis propria, (4) muscularis propria minus the acoustical interface between the submucosa and muscularis propria, and (5) serosa and subserosal fat. This interpretation takes into consideration the echoes produced by the tissue layers and the echoes produced by the interfaces between layers. Abnormal findings on ultrasound images of neoplastic and inflammatory diseases correspond to histologic tissue structure. When properly interpreted, ultrasound images of the gastrointestinal wall can provide potentially useful diagnostic information.

Digestive System↗