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Biomedical subjects

M H Wu

Publications and source records attributed to M H Wu.

At least 109 records · Page 6Linked to original sources
PubMed1998

Long QT syndrome manifested as fetal ventricular tachycardia and intermittent AV block.

A case of long QT syndrome diagnosed in the early neonatal period is described. This full-term female baby had intermittent atrioventricular (AV) block and ventricular tachycardia detected antenatally at the gestational age of 26 weeks. Sinus rhythm with prolonged QT interval (QTc = 0.636 sec) was found soon after birth. She developed variable degree of AV block with alternating left and right bundle branch block, which suggested the presence of multilevel AV block. Her mother had no lupus autoantibodies. Auditory brain stem evoked potential was normal. Family study revealed QT prolongation in her grandmother. Her condition improved after pacemaker implantation and oral beta-blocker usage.

Electrocardiography↗
PubMed1998

Human herpesvirus 8 as a potential sexually transmitted agent in Honduras.

The seroprevalence of human herpesvirus 8 (HHV-8) was studied in 326 human immunodeficiency virus (HIV)-positive and -negative persons from Honduras; women constituted 77% (n = 251) of the subjects. Sera were tested for lytic HHV-8 antibodies by an IFA, and positive samples were confirmed by a radioimmunoprecipitation assay. Of the 326 persons tested, 58 (17.8%) had HHV-8 antibodies. Among the HIV-infected women, 22.7% were seropositive; 11.3% of the HIV-negative women were seropositive. HHV-8 seroprevalence was almost four times higher in HIV-positive female commercial sex workers (36%) than in HIV-negative female non-commercial sex workers (9.9%; odds ratio = 3.8, 95% confidence interval = 1.1-13; P = 0.01), suggesting that commercial sex work is a risk factor for HHV-8 infection. In the men studied, the overall HHV-8 seroprevalence was 22.6%, with a seropositivity rate of 28% for HIV-positive men compared with 12% for HIV-negative men.

AIDS-Related Opportunistic Infections↗
PubMed1998

Prevalence and manifestations of hepatitis C seropositivity in children in an endemic area.

BACKGROUND: According to our previous studies, Paisha Township in Penghu Islets is an endemic area for hepatitis B virus and hepatitis C virus (HCV) infection and for hepatocellular carcinoma. We conducted this study to understand the prevalence of anti-HCV seropositivity among children in this area and to observe clinical manifestations of anti-HCV-positive children. METHODS: In March, 1994, 1164 (93.6%) of 1243 students from all 6 kindergartens, 9 primary schools and 3 middle schools in Paisha Township participated in the screening for anti-HCV by enzyme immunoassay with second generation commercial kits (Abbott EIA 2.0). Anti-HCV tests were duplicated for the positive sera in 2 laboratories. All anti-HCV-positive children were followed annually for 2 years. RESULTS: The prevalences of children from kindergartens (ages 3 to 6 years), primary schools (ages 7 to 12 years) and middle schools (ages 13 to 15 years) were 0% (0 of 229), 0.8% (5 of 617) and 1.9% (6 of 318), respectively. Initially the optic density (OD) values of anti-HCV were > 2.0 in 4 cases (36%), between 1.0 and 2.0 in 2 cases, and < 1.0 in the other 5 cases. None had sonographic parenchymal changes in the liver. In the 2-year follow-up of the anti-HCV-positive subjects, type 2a HCV-RNA persisted in 3 of 4 children with an OD of anti-HCV more than 2.0; 2 of them had 2 elevations of alanine transaminase values. Four of 7 children with an OD of 2.0 or less had a decrease in OD values in the follow-up examinations, and 2 of them became anti-HCV-negative. CONCLUSION: Only 36% (4 of 11) of anti-HCV-positive children had an OD of > 2.0. Subjects with sequentially low OD might recover from chronic HCV infection without detectable HCV RNA and with normal alanine aminotransferase values.

Adolescent↗
PubMed1998

Morphological characterization of ventricular septal defect with posterior deviation of the outlet septum.

Ventricular septal defect (VSD) with posterior deviation of the outlet septum is frequently associated with left ventricular outflow obstruction and aortic arch anomalies. In this study, 17 patients with large VSD and posterior deviation of the outlet septum were evaluated. The VSD was further classified into 'high' and 'low' types according to the extension of the VSD; the high-type VSD (8 patients) extended mainly to the outlet or infundibular portion and the low-type VSD (9 patients) extended mainly to the trabecular or inlet portion. Related morphological features, such as outlet septum hypoplasia, muscle bundle between aortic-mitral valve junction, pulmonary artery overriding and aortic arch anomalies, were found more frequently in patients with high-type VSD, while tricuspid valve straddling and outlet septum hypertrophy were found more often in patients with low-type VSD. This classification for VSD with posterior deviation of the outlet septum helps to predict the morphological features of left ventricular outflow tract and aortic arch anomalies.

Echocardiography↗
PubMed1998

Spiral computed tomographic angiography--a new technique for evaluation of vascular access in hemodialysis patients.

Spiral computed tomographic angiography (CTA), a new noninvasive imaging technique, was used to study 10 arteriovenous fistulas (AVF) in 9 hemodialysis patients. Digital subtraction angiography (DSA) was also performed as a gold standard for comparison. AVF stenosis was graded by a four-point scale: grade 0, well patency of supplying artery, anastomosis and drainage vein; grade 1, < 50% stenosis; grade 2, 50-70% stenosis; grade 3, 70-99% stenosis, and grade 4, total occlusion. We found CTA correlated closely to DSA in detecting both stenosis and dilatation of AVF and it spared all the shortcomings of DSA. CTA has the potential to be alternative for imaging of dialysis fistulas. Further studies will be performed to specify the role of CTA images in the assessment of the hemodialysis vascular access.

Adult↗
PubMed1998

Evolution of dilated cardiomyopathy from hypertrophic obstructive cardiomyopathy in a child.

Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) are two different diseases and have distinct etiologies. HCM is rare in children and rarely progresses to DCM. We report a 5-year-old Taiwanese girl with a definite diagnosis of hypertrophic obstructive cardiomyopathy. The diagnosis was based on echocardiograms, cardiac catheterization, and endomyocardial biopsy. However, the clinical features progressed to a picture of nonobstructive HCM at age 9, and the patient developed dilated poorly contractile ventricles with intractable congestive heart failure at age 10. She died from ventricular tachycardia at age 13. This report emphasizes the importance of periodic reevaluation for children with HCM.

Cardiomyopathy, Dilated↗
PubMed1997

Prenatal sonographic diagnosis of single umbilical artery.

PURPOSE: We evaluated the reliability of prenatal sonography and the usefulness of the umbilical vein and artery diameter ratio, transverse umbilical artery diameter, and systolic-diastolic ratio in detecting single umbilical artery (SUA). METHODS: In 24 of 6,970 fetuses, SUA was detected using prenatal sonography and confirmed at birth. These cases were retrospectively reviewed. RESULTS: Four fetuses had major malformations, and 1 had a minor anomaly. Thirteen fetuses with SUA underwent chromosomal analysis, and only 2 had abnormal karyotypes. Most of the SUA fetuses had a normal systolic-diastolic ratio. CONCLUSIONS: Our retrospective study determined that the prognosis of SUA fetuses is good when there is no concurrent anatomic or chromosomal abnormality. Although some reports claim that the transverse umbilical artery diameter or the ratio between umbilical vein and artery diameters can predict SUA, we found no significant improvement in the recognition of SUA using these parameters.

Adult↗
PubMed1997

Transcatheter closure of a huge pulmonary arteriovenous fistula with embolization coils.

A 46-year-old female with bilateral pulmonary arteriovenous fistulas was treated with Gianturco coil occlusion. The small right lung fistula was closed with a 6 mm coil, whereas the huge left lung fistula was occluded with three coils (one 10-mm and two 8-mm). Angiography 3 d later demonstrated recanalization of the left fistula. Two 8 mm coils were inserted to achieve complete obstruction again. She developed pulmonary infarction in the left lung 2 d later, which recovered without sequelae. We conclude that coil embolization for huge pulmonary arteriovenous fistula is feasible but may result in pulmonary infarction.

Adult↗
PubMed1997

Surgical treatment of pediatric lung abscess.

Eight pediatric patients with lung abscesses underwent surgical intervention in our hospital during a 7-year period. All the abscesses were associated with severe sepsis or complicated by a bronchopleural fistula that did not respond to medical treatment and tube thoracostomy. Seven patients required unilateral thoracotomies, and one patient with bilateral lesions required simultaneous bilateral thoracotomies. One tension pneumatocele required a preceding pneumonostomy. All patients underwent decortication and at least one additional surgical procedure consisting of: lung debridement plus bronchial closure (n = 4); lobectomy (n = 2); bisegmentectomy (n = 3); and/or segmentectomy (n = 1). There were no operative deaths, but two patients had persistent air leakage that was treated by bronchial closure. The average hospital stay was 22 days (postoperative 10.1 days). All the patients recovered completely. For many pediatric lung abscesses that do not respond to medical treatment and simple drainage procedures, surgical intervention is indicated and can shorten the hospital stay.

Bronchial Fistula↗
PubMed1997

Congenital bilateral agenesis of diaphragm: report of a case.

UNLABELLED: Bilateral agenesis of the diaphragm is a rare, life-threatening malformation. Infants with this defect rarely survive to have surgical intervention. We report a 32-week premature female infant who was born to a 36-year-old mother via vaginal delivery. The pregnancy course was complicated by hypertension and polyhydramnios. Cytogenetic study showed a normal 46 XX female karyotype. She had cyanosis, respiratory distress and scaphoid abdomen at birth. A roentgenograph confirmed the diagnosis of diaphragmatic hernia. Surgery was performed at 21 h of age. Bilateral agenesis of diaphragm, herniation of abdominal organs and oesophagus and pulmonary hypoplasia were noted. Furthermore, stomach and spleen were adherent to the mediastinum and vertebrae. The patient developed hypotension and persistent hypoxaemia and expired at age of 26 h. Autopsy revealed bilateral agenesis of diaphragm, hypoplasia of lungs, and pancreas fibrosis with mild hypoplasia of islets of Langerhans. CONCLUSION: Bilateral agenesis of diaphragm associated with pancreas fibrosis is a rare entity, and its clinical significance needs further investigation.

Abnormalities, Multiple↗
PubMed1997

Accelerated endothelialization model for the study of Dacron graft healing.

Accelerated endothelialization was studied by creating a vascular tissue environment around porous Dacron grafts. Three study groups, each containing 10 dogs, were divided equally into 2- and 4-week implant periods, with 8 mm x 6 cm knitted Dacron grafts implanted in the abdominal aorta. Grafts in group 1, the control group, were implanted conventionally. In group 2 each implanted graft was completely wrapped in a resected segment of the autogenous inferior vena cava, with its intima against the wall. In group 3 the adventitial side of the vein was wrapped against the wall. The vein wrap produced accelerated endothelialization as follows: endothelial-like cell coverage scores at 2 and 4 weeks were, respectively, 78% and 98% for group 2 and 80% and 95% for group 3, compared to only 14% and 50% for group 1 (p < 0.05). The neointima, which contained smooth muscle cells, was formed as early as 2 weeks in the vein-wrapped grafts. There were no differences in the speed of healing or in healing patterns according to whether the intimal or the adventitial side of the inferior vena cava was placed against the graft. Histologic findings did not support the hypothesis that accelerated flow surface endothelialization results in direct migration of endothelial cells from the intima of the vein wrap, and there was no clear correlation between the surface endothelial-like cell coverage and microostia. To gain further insight into why accelerated healing occurs in this model, earlier observations accompanied by molecular biology analysis are needed, and vein wrap studies provide a method of comparison for this work.

Animals↗
PubMed1997

Early presence of endothelial-like cells on the flow surface of porous arterial prostheses implanted in the descending thoracic aorta of the dog.

The purpose of this study was to investigate early arterial graft healing and its sources in porous Dacron prostheses after very short implantation periods in the dog, using extensive histologic examination of serial sections. Preclotted Dacron prostheses 6 cm long and 8 mm in diameter were implanted in the descending thoracic aorta (DTA) of 14 dogs, and retrieved at 7 days (n = 6), 10 days (n = 4), and 14 days (n = 4). The flow surface was assessed for thrombus coverage, endothelial-like cell (ELC) coverage, and the number of microvessel ostia. Where an ELC island was identified under the stereomicroscope, full-wall longitudinal tissue samples were taken, and embedded in resin for light microscopy study of 6-microns, H&E-stained serial sections to determine general healing and interstitial tissue presence. If there was more than one ELC island, another full-wall sample was taken and embedded in paraffin for staining with laminin, collagen IV, and smooth muscle alpha-actin antibodies, and PTAH. All grafts were patent with very little thrombus. Islands of endothelial-like cells were found for each time period, and on all 14-day grafts. Endothelial-like cell coverage was highest at 14 days. On 7- and 10-day grafts, cells proved to be endothelium were found in the middle of the flow surface, unconnected to either pannus or perigraft tissue ingrowth. Healing occurs as early as 7 days in porous knitted Dacron grafts. The source at periods earlier than 10 days appears to be cells from the blood stream.

Animals↗
PubMed1997

Enhanced interleukin-4 expression in patients with endometriosis.

OBJECTIVE: To investigate the expression of cytokines by T-helper cells type 1 (interleukin [IL]-2 and interferon-gamma [IFN-gamma]) and type 2 (IL-4 and IL-10) in peripheral blood monocytes and peritoneal fluid (PF) cells from patients with endometriosis. DESIGN: Peripheral blood (PB) monocytes and PF cells from patients with endometriosis were isolated and the expression of cytokines investigated. SETTING: Institute for the treatment of endometriosis and research institute in university-based medical center. PATIENT(S): The study included 7 women with normal pelvic structure, 36 patients with endometriosis, and 7 women with pelvic adhesion but without apparent endometriotic lesion. The existence and severity of endometriosis was determined by laparoscopic examination. INTERVENTION(S): All patients received laparoscopic operation to identify the existence and stages of endometriosis. Danazol (200 mg, twice daily) was prescribed for those with endometriosis. MAIN OUTCOME MEASURE(S): Transcription of cytokines were directly analyzed using the reverse transcriptase-polymerase chain reaction method. The concentrations of cytokines in peritoneal fluids and sera were analyzed by the ELISA. RESULT(S): Levels of IL-4 messenger RNA (mRNA) and protein in the PB and peritoneal cells of patients with endometriosis were higher than those of normal patients, whereas levels of IFN-gamma mRNA and protein were suppressed. There were no significant changes in the mRNA or protein levels of IL-2 or IL-10 in both peritoneal fluids and sera. The level of IL-4 was reduced to normal after combined treatment with laparoscopic surgery and danazol. The secretion of IFN-gamma was elevated after treatment. CONCLUSION(S): Cytokine secretion by T-helper cells type 1 and type 2 is altered in women with endometriosis, suggesting that these T-helper subsets play a role in the immunologic responses to endometriosis.

Ascitic Fluid↗
PubMed1997

Effect of altered blood flow on the caliber and morphology of the internal thoracic artery in the dog.

OBJECTIVE: The purpose of this study was to evaluate in dogs the effect of blood flow alteration on caliber and morphology of in situ internal thoracic arteries. METHODS: Six dogs underwent creation of a unilateral distal arteriovenous fistula between the internal thoracic artery and vein at the sixth rib to create high flow, and in six others the internal thoracic artery was unilaterally skeletonized and dissected. For both groups the contralateral internal thoracic artery served as the control; sides were alternated among cases. Blood flow was measured for shear stress calculation before and after surgical alteration. After 2 months, internal thoracic arteries were harvested with the entire anterior chest plate, which was dynamically inflated and fixed with 10% formalin at a controlled pressure of 120 mm Hg after angiography had been done at the same pressure. The luminal diameters were then measured at eight levels on the angiograms. Arterial tissue samples were taken at three levels and embedded, sectioned, and treated with hematoxylin-eosin and Verhoeff-van Gieson stains. Digital imaging analysis was used for quantitative morphometric studies. RESULTS: All fistulas remained patent. In comparison with control arteries, high-flow internal thoracic arteries dilated and low-flow internal thoracic arteries narrowed, which was associated with significant change in shear stress for both groups. There were no substantial structural changes in the walls of either group. CONCLUSION: In the dog, the luminal diameter of the internal thoracic artery responds to altered blood flow without intimal thickening or other undesirable wall changes.

Animals↗
PubMed1997

Comparison of aging and hypercholesterolemic effects on the sodium inward currents in cardiac myocytes.

To study and to compare the hypercholesterolemic and aging effect on the sodium inward currents (I(Na)) in cardiac myocytes, whole-cell clamp recordings were made in single cardiac myocyte isolated from normo- and diet-induced hypercholesterolemic rabbits of different age groups. The cell capacitance of adult and hyperlipidemic myocytes seemed larger than that of young and normolipidemic ones. However, the sodium current density at a holding potential of -80 mV on adult and hypercholesterolemic ventricular sarcolemma was significantly lower than that on young and normolipidemic one (adult hyperlipidemic: -15.3+/-2.4 pA/pF (n=16), adult control: -28.1+/-3.4 pA/pF (n=13), young hyperlipidemic: -39.5+/-5.4 pA/pF (n=19), young control: -67.3+/-7.8 pA/pF (n=12)). In aging process, this effect was due to a decrease in channel number, a leftward shift in the inactivation potential and a slowing of the time course of recovery. In hypercholesterolemia, however, the major cause was due to the functional change of sodium currents. In addition to decreasing the sodium current magnitude, hypercholesterolemia lowered the threshold for excitation of cardiac myocytes (-50 mV vs -40 mV). In conclusion, aging process depressed the sodium channel activity in ventricular myocytes. In addition to inducing some similar functional alterations of I(Na) as aging process, long-term hypercholesterolemia could also increase the excitability in cardiac myocytes, which was different from aging process.

Aging↗
PubMed1997

Implant site influence on arterial prosthesis healing: a comparative study with a triple implantation model in the same dog.

PURPOSE: The purpose of this study was to develop a cost-effective canine graft healing model that gives information on various implant sites and controls for variable factors between graft locations and between animals and to compare the influence of implant site (retropleural, retroperitoneal, and subcutaneous areas) on arterial graft healing in the same subject under such controlled study conditions. METHODS: Five mongrel dogs were studied for 8 weeks, and one was studied for 3 years. Each received three porous Dacron grafts during the same surgery: a carotid-femoral bypass (C-FB) and interposition grafts in the descending thoracic aorta and abdominal aorta. To produce comparable shear stress calibers of the C-FB and abdominal aorta grafts were 2 mm less than those of the descending thoracic aorta, and a distal arterio-venous fistula was created to further increase the C-FB flow. For comparable blood aggregation status platelet aggregation was preevaluated and adjusted with antiplatelet agents. Graft flow surfaces were assessed for thrombus-free surface and endothelial-like cell coverage scores. Tissue samples were studied with hematoxylin-eosin, factor VIII/ von Willebrand factor, smooth muscle alpha-actin staining, and scanning electron microscopy and transmission electron microscopy. RESULTS: All grafts were patent. Shear stress for the three grafts and platelet aggregation among the study subjects were comparable. Healing of descending thoracic aorta and abdominal aorta grafts was similar, but C-FB healing was slow, incomplete, and uneven, with a high incidence of seroma. Eight-week and 3-year results were comparable. CONCLUSIONS: This model gives broad healing information about the areas where grafts are often implanted in humans. Eight weeks appears to be a sufficient period to reflect basic and general healing characteristics. Grafts heal better in the retropleural and retroperitoneal areas than in the subcutaneous tissues.

Animals↗
PubMed1997

Endothelium on the flow surface of human aortic Dacron vascular grafts.

PURPOSE: We have previously observed endothelium on two human vascular prostheses explanted under optimal conditions for flow surface preservation. In this study we sought to further verify the hypothesis that endothelialization can occur on clinical grafts and that it can be detected in specimens that have been promptly removed and properly preserved in a timely manner. METHODS: We studied 29 aortic grafts. Of these, 11 Dacron bypass grafts were in a condition suitable for analysis with light microscopy and immunocytochemistry staining, and scanning and transmission electron microscopy. RESULTS: Three grafts had endothelium beyond the pannus, identified by factor VIII/ vWF, Ulex europaeus agglutinin, and collagen IV positivity. Specimen A, a knitted 6-year implant, was preserved by embalming 3 hours after the patient's death and had a firmly attached outer capsule with fibroblasts, collagen, giant cells, and microvessels in the interstices. Specimen B, a woven 18-year implant, was retrieved at reoperation and immediately fixed in 10% formalin; it had no outer capsule and no tissue ingrowth. Specimen C, a woven 7-year implant, was removed and fixed 5 hours after the patient's death; it had a firmly attached outer capsule but no tissue ingrowth beyond the outer portion of the wall. CONCLUSIONS: The rapidity with which the specimens were fixed probably enabled identification of endothelium. These findings suggest that endothelialization of synthetic arterial grafts may occur more frequently in human beings than previously recognized.

Aged↗