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Biomedical subjects

M H Wu

Publications and source records attributed to M H Wu.

At least 163 records · Page 9Linked to original sources
PubMed1995

Surgical treatment of complete atrioventricular septal defect associated with tetralogy of Fallot.

The combination of complete atrioventricular septal defect (AVSD) and tetralogy of Fallot (TF) was reported to occur in less than 2% of patients undergoing repair of TF. From September 1981 to November 1989, five consecutive patients with such combination underwent total correction at National Taiwan University Hospital. Their age ranged from 3.8 years to 6.3 years. Two cases were associated with Down's syndrome. All interventricular communications were repaired by combined transatrial and transventricular approach and a separate pericardial patch was used to repair the interatrial communication. The transannular patch (TAP) was not used in one case; of the four cases with TAP, a pericardial monocusp was mounted in one of them. There was one hospital mortality, and one late death. Both were related to intractable right heart failure. We conclude that total repair of this anomaly could be accomplished after 3 years of age provided there is thorough awareness of anatomical features and avoidance of right heart failure.

Child↗
PubMed1995

Translocation of nucleophosmin from nucleoli to nucleoplasm requires ATP.

The movement of nucleophosmin from nucleoli to nucleoplasm in HeLa cells induced by cytotoxic drugs and detected by immunofluorescence is inhibited by concomitant treatment with antimycin A in glucose-free medium. Incubation of HeLa cells with antimycin A (300 nM; 30 min) and glucose-free medium resulted in an approximately 90% decrease in cellular ATP pools. To study the biochemical events involved in nucleophosmin translocation, we used an in vitro system consisting of Triton-permeabilized HeLA cells. Incubation of permeabilized cells with ATP (0.5 mM; 1 h) resulted in the translocation of nucleophosmin from nucleoli to nucleoplasm and cytoplasm. Similarly to drug-induced nucleophosmin translocation in whole cultured cells, there is no reduction (measured by e.l.i.s.a.) or degradation of nucleophosmin or change in the ratio of the high-molecular-mass form to the monomeric form (ascertained by Western blotting) during ATP treatment of permeabilized cells. Together, these results indicate a requirement for ATP for redistribution of nucleophosmin from nucleoli to nucleoplasm. Because this permeabilized cell model is simple and efficient and works effectively with exogenous factors, it should provide a powerful tool for investigating the biochemical features of nucleophosmin translocation from nucleoli to nucleoplasm.

Adenosine Triphosphate↗
PubMed1995

Prenatal diagnosis of recurrence of short rib-polydactyly syndrome.

We describe a nonconsanguineous couple whose 3 successive pregnancies, including one pair of twins, led to the birth of 4 infants with short rib-polydactyly syndrome (SRPS). Flat face, hypoplastic thorax, short limbs and ribs, polydactyly, absence of penis, and death after birth were noted in the first affected male baby. The affected female twins were detected prenatally by ultrasonography and had the same characteristics, but milder than the previous one. Serial measurements of the thoracic circumference and the 4 limbs were obtained by ultrasound, and showed progressively decreased ratio of thoracic to abdominal circumference and shortness of the limbs. The last male baby also had a similar but variable expression in prenatal ultrasonography.

Adult↗
PubMed1995

Prenatal ultrasonographic diagnosis of congenital megalourethra.

Congenital megalourethra is a rare genital anomaly characterized by dilatation of the penile urethra without evidence of distal obstruction. Reports of the prenatal diagnosis of this condition in the literature are limited. We present a case of congenital megalourethra with obstructive uropathy from the posterior urethra diagnosed prenatally at 18 weeks of gestation. 'Prune-belly'-like features, colonic malrotation, and imperforate anus were also found on autopsy.

Adult↗
PubMed1995

Differential effect of the retropleural and retroperitoneal environments on healing of the inner wall of porous fabric prostheses in the thoracic and abdominal aorta of the same dog.

Healing of the inner wall of the same preclotted knitted Dacron arterial prostheses was compared in the descending thoracic aorta (DTA) and the abdominal aorta (AA) of the same dog. Each of 16 dogs received this dual implantation with study periods of 4 weeks for five dogs, 8 weeks for five dogs, and 16 weeks for six dogs. Healing was studied with light microscopy, scanning electron microscopy, transmission electron microscopy, and immunocytochemistry identification. The outer capsule was firmly adherent to the Dacron framework of all grafts implanted in the DTA; advanced healing of the inner wall of all thoracic grafts was present by 4 weeks, nearly complete healing by 8 weeks, and complete healing by 16 weeks. In contrast, the outer capsule was either not attached or only loosely adherent to the Dacron framework in eight AA grafts (50%), and in these implants no healing of the inner wall occurred beyond the limited perianastomotic pannus zone. In the other eight implants in which the outer capsule was firmly adherent to the Dacron framework, healing was roughly comparable to that in the grafts implanted in the DTA. This study demonstrated that (1) DTA grafts heal faster and more completely than AA grafts, (2) healing and endothelialization are related to the tightness of the outer capsule, (3) there is a high incidence of loose tissue attachment in the AA, and (4) healing of aortic grafts is site specific.

Animals↗
PubMed1995

Intravaginal foreign body retained for a long duration.

An intravaginal foreign body of long duration can pose a diagnostic dilemma, since a number of diagnostic modalities may fail to detect its existence. We present the case of an 8-year-old girl who suffered from a bloody, malodorous vaginal discharge for over 4 years, during which time she had been evaluated by several gynecologists. A vaginal examination performed under analgesia revealed a pinpoint-sized opening 2 cm above the hymen. We inserted a cannula and injected radio-opaque contrast medium. An intravaginal filling defect was visible, which strongly suggested the presence of a foreign body. An incision through this scarred area was performed and two foreign bodies, one shaped like a plastic tube and the other a cap, were removed. We conclude that vaginography may provide an alternative diagnostic tool for this condition.

Child↗
PubMed1995

Ductus-dependent aortic coarctation with a left-to-right shunt through the ductus: report of one case.

A 20 days old female baby presenting with dyspnea was found to have coarctation of the aorta and patent ductus arteriosus by echocardiography. The Doppler spectral display disclosed mainly a left-to-right shunt through the ductus. Therefore, the prostaglandin El infusion was discontinued. She developed acute left heart failure, and the echocardiograms at that time showed a markedly narrowed juxtaductal aortic coarctation with a closed ductus. After resumption of prostaglandin El, with an attenuated juxtaductal aortic coarctation, the left ventricular contractility and the systemic perfusion improved. Therefore, we conclude that the central role of a patent ductus in such a patient is to avoid the ductal constriction which will worsen the aortic coarctation.

Alprostadil↗
PubMed1995

Evolution of coronary artery pattern according to short-axis aortopulmonary rotation: a new categorization for complete transposition of the great arteries.

OBJECTIVES: We studied the correlation between coronary artery pattern and aortopulmonary rotation in complete transposition of the great arteries. BACKGROUND: Classifications of the coronary arteries in complete transposition are puzzling and incomplete. METHODS: Coronary artery anatomy and relation of the great arteries were identified at angiography, echocardiography, surgical intervention or autopsy in 76 patients with complete transposition from 1988 to 1993. Five main types (type 0 and Shaher types 1,2,4 and 9) and their similar variants of epicardial configuration were categorized into five patterns (O, I, II, IV and IX). In addition, data from 568 cases from published reports were collected for analysis. RESULTS: As the aorta rotated from a left anterior to a directly anterior location relative to the pulmonary trunk, the left anterior descending coronary artery arose from the left-hand sinus together with the right coronary artery (type 0, one case decreased to no cases); then it gradually shifted to the left to have the same origin as the left circumflex coronary artery from the right-hand sinus (type 1, 10 cases increased to 146, p < 0.0003). When the aorta rotated farther clockwise from directly anterior to right anterior (type 1, 146 cases increased to 235; type 2, 9 cases increased to 50, p < 0.0006) or from right anterior to right lateral (type 1, 235 cases decreased to 6 cases; type 2, 50 cases decreased to 20, p < 0.00000), the left circumflex coronary artery tended to move retropulmonically and originated from the left-hand sinus with the right coronary artery (type 2). When the aorta moved from right anterior to right lateral (type 2, 50 cases decreased to 20; type 4, 13 cases increased to 14, p < 0.031) or from right lateral to right posterior (type 2, 20 cases decreased to 1; type 4, 14 cases increased to 16, p < 0.0003), the right coronary artery shifted to the right-hand sinus anteaortically to join the left anterior descending coronary artery (type 4). Finally, the left anterior descending coronary artery combined with the left circumflex coronary artery (type 9, 12 cases increased to 21, p = 0.407) to become the usual pattern for normally related great arteries. Eta-square analysis showed that the evolution from pattern O to IX was dependent on clockwise aortopulmonary rotation. CONCLUSIONS: The coronary arteries in complete transposition of the great arteries can be classified into five patterns and their evolution deduced on the basis of aortopulmonary rotation. Dependence of coronary artery type on aortopulmonary rotation made it possible to anticipate the coronary pattern from the relation of the great arteries in transposition.

Adolescent↗
PubMed1995

Comparison of the effect of monopolar and bipolar cauterization on skeletonized, dissected internal thoracic arteries.

The internal thoracic artery is preferable to the saphenous vein for use as a conduit for coronary artery bypass. More extensive use is possible if this artery is mobilized in a skeletonized form to provide greater length. Internal thoracic arteries are usually mobilized with cauterization. This study compared the effectiveness and effects on neighboring areas of division of the branches of the canine internal thoracic artery with bipolar cauterization and monopolar cauterization. Branch closure was significantly more secure in the bipolar cauterization group, with bleeding in 25 (9%) of 279 branches of 15 internal thoracic arteries treated with monopolar cauterization, in contrast to bleeding in 4 (1.3%) of 306 branches in the 15 internal thoracic arteries treated with bipolar cauterization, which were paired with the group treated with monopolar cauterization. The group of internal thoracic arteries treated with monopolar cauterization had a significantly higher prevalence of leakage when luminal pressure was increased from 120 to 160 mm Hg. Scanning electron microscopy demonstrated partial loss of endothelial cells on the flow surface of internal thoracic arteries treated with bipolar cauterization, compared with almost complete loss of endothelial cells around the orificial areas after monopolar cauterization. Secondary bipolar cauterization treatment caused only slightly more damage than primary treatment, but secondary monopolar cauterization was much more severe and extensive than primary treatment. These data suggest that bipolar cauterization is preferable to monopolar cauterization for skeletonized dissection of the internal thoracic artery.

Animals↗
PubMed1995

Bronchial rupture caused by blunt chest injury.

We have surgically treated six patients with bronchial rupture caused by blunt chest injury in the past 5 years. All injuries resulted from traffic accidents, except in one patient who was hit by a crane. Clinical manifestations included chest pain (n = 6), subcutaneous emphysema (n = 4), and dyspnea (n = 6). Roentgenographic findings were tension (n = 3) or nontension (n = 3) pneumothorax, subcutaneous emphysema (n = 4), pneumomediastinum (n = 3), deep cervical emphysema (n = 5), and delayed collapse of the affected lung (n = 3). Three patients had associated injuries: right clavicle and rib fractures in the first; right humeral, scapular, and multiple rib fractures and left sternoclavicular joint dislocation in the second; and left clavicle fracture in the third. These six patients all underwent immediate tube thoracostomy and then bronchoplasty. Bronchoplasty was performed within 3 days in four patients and on days 16 and 30, respectively, in the other two patients. The affected lung demonstrated full expansion in all patients immediately after bronchoplasty. Follow-up bronchoscopy showed good patency of all bronchi.

Accidents, Traffic↗
PubMed1995

Definitive proof of endothelialization of a Dacron arterial prosthesis in a human being.

A 10 mm woven Dacron axillofemoral bypass graft was removed from a 65-year-old patient during redo surgery after an implant period of 26 months, because of a large seroma that surrounded the entire length of the graft. Tissue blocks were taken from representative areas along the entire length of the graft surface and evaluated by light microscopy with hematoxylin and eosin and Masson trichrome staining, scanning electron microscopy, transmission electron microscopy, and immunocytochemical staining. Paraffin-embedded sections were stained with smooth muscle cell alpha-actin, which demonstrated smooth muscle cells in the pseudointima, and Ham 56 stain to identify macrophages. Endothelial factor VIII/von Willebrand factor and Ulex europaeus agglutinin identified human endothelial cells on the flow surface, in areas far removed from the anastomoses to the native vessels. This is the first definitive proof in a human of endothelialization of a synthetic arterial graft beyond the pannus ingrowth zone.

Aged↗
PubMed1995

Effect of differential shear stress on platelet aggregation, surface thrombosis, and endothelialization of bilateral carotid-femoral grafts in the dog.

PURPOSE: The purpose of this study was to determine the effects of increased shear stress on the aggregability of platelets as they traverse a long, small-caliber (6 mm) Dacron graft in the dog and on the surface thrombosis and endothelialization of such a graft. METHODS: Each of nine dogs received bilateral carotid-femoral artery grafts, approximately 75 cm long, for 3 months; one graft of each pair had a distal femoral arteriovenous fistula to produce a higher shear rate than the contralateral graft. Platelet aggregation scores were determined on blood withdrawn from the external jugular vein and from the proximal and distal ends of the grafts in each animal. Graft flow rates, which were used in the computation of shear stress, and luminal pressure gradients through grafts were measured during surgery and specimen retrieval. Specimens were studied with light microscopy after hematoxylin and eosin and immunocytochemical staining and by scanning electron and transmission electron microscopy to evaluate the nature, composition, and thickness of the flow surface lining, as well as the transmural healing. RESULTS: Two high-shear stress and two low-shear stress grafts occluded unilaterally; five dogs had bilaterally patent grafts, allowing comparative analyses. All subjects had low platelet aggregability with aspirin. Platelet aggregation scores taken from proximal and distal ends of the grafts were not significantly different. The high-shear stress grafts had significantly more endothelial-like cell coverage (p < 0.0371) than the low-shear stress grafts, less flow-surface thrombus (p < 0.0056), and a thinner surface lining (p < 0.0029), on both the neointima and pseudointima. CONCLUSIONS: In subjects with low platelet aggregation scores, long Dacron grafts do not elevate platelet aggregability of blood flowing through them. High-shear stress grafts have less flow surface thrombus, more endothelialization, and a thinner surface lining than do low-shear stress grafts.

Animals↗
PubMed1995

Electrophysiological basis for antiarrhythmic efficacy, positive inotropy and low proarrhythmic potential of (-)-caryachine.

1. (-)-Caryachine, isolated from the plant (Cryptocarya chinensis), increased the contractility of atrial and right ventricular strips and significantly suppressed the reperfusion arrhythmias in adult rabbit heart (ED50 = 1.27 microM). 2. Data obtained by the whole-cell voltage clamp technique has shown that (-)-caryachine causes a negative shift of the steady-state Na channel inactivation and a slower rate of recovery from inactivation. The maximal Na current amplitude decreased to 67 +/- 7%, 29 +/- 8% and 12 +/- 5% after 0.5, 1.5 and 4.5 microM (-)-caryachine, respectively. 3. This agent also had effects on the time- and voltage-dependent K currents. (-)-Caryachine markedly suppressed the 4-AP-sensitive transient outward current (I10). However, it produced very little voltage-dependent shift in inactivation. After 0.5, 1.5 and 4.5 microM of the compound, the respective value of I10 elicited at +60 mV was 80 +/- 7%, 45 +/- 8% and 15 +/- 3%. At higher concentrations, the inward rectifier K current (IK1) was also inhibited but to a much smaller extent. Its slope conductance after 0.5, 1.5 and 4.5 microM (-)-caryachine was reduced to 71 +/- 9%, 51 +/- 12% and 42 +/- 11%, respectively. The outward hump of inward rectification was not changed. 4. In contrast, the L-type Ca current was not significantly changed by (-)-caryachine. 5. Electrophysiological studies in perfused whole heart preparations revealed that (-)-caryachine increased the intra-atrial conduction interval and also prolonged the atrial refractory period. No proarrhythmic effects were induced during the infusion of this compound (up to 13.5 microM). 6. We conclude that (-)-caryachine predominantly blocks the Na and I10 currents. These changes alter the electrophysiological properties of the heart and terminate the induced ventricular arrhythmias. The relatively selective I10 inhibition, safety margin of Ik1 suppression and lack of effect on Ica-L will provide an opportunity to develop an effective antiarrhythmic agent with positive inotropy as well as low proarrhythmic potential.

Animals↗
PubMed1995

Implication of anterior septal malalignment in isolated ventricular septal defect.

OBJECTIVE: The aim was to define the long term prognosis of isolated ventricular septal defect (VSD) with anteriorly malaligned outlet septum. DESIGN: Cohort study. SETTING: University hospital, tertiary medical care centre. PATIENTS: Between July 1986 and June 1993, 63 patients were studied with an isolated VSD and anteriorly malaligned outlet septum (59 perimembranous; 4 muscular outlet). MAIN OUTCOME MEASURES: The diagnosis of septal malalignment, aneurysmal transformation, right ventricular obstruction, subaortic ridge, and aortic valve prolapse was based on echocardiographic criteria, then confirmed by angiography in 33 patients and by surgery in 28. An actuarial curve for each event was obtained by Kaplan-Meier non-parametric analysis and the significance was examined by log-rank test. RESULTS: Aneurysmal transformation decreased the size of the VSD in 52% of the patients, but was also associated with the appearance of subaortic ridge (p < 0.05). Progressive obstruction in the right ventricle was observed in 51%, more often in those without aneurysmal transformation (p < 0.05). Aortic valve prolapse was quite common whether or not aneurysmal transformation occurred (33% and 23%, respectively). This was attributed to the location of the VSD and the anterior malalignment of the outlet septum. Surgery was performed in 28 patients at a median age of 50 months because of significant left to right shunt (n = 5), or the development of obstruction in right ventricle (n = 9), aortic valve prolapse (n = 3), or combinations (n = 11). The presence of subaortic ridge per se was not considered to be a surgical indication. CONCLUSIONS: Anteriorly malaligned VSDs have variable presentation. Careful echocardiographic evaluation is needed to identify various combinations of progressive right ventricular obstruction, aneurysmal transformation, subaortic ridge, or aortic valve prolapse. In extreme cases a patient may have a pathology complex comprising right ventricular outflow obstruction, subaortic ridge, aortic valve prolapse, and anteriorly malaligned VSD.

Child, Preschool↗
PubMed1995

Electrophysiological properties of dual atrioventricular nodes in patients with right atrial isomerism.

There are reports that in right atrial isomerism the conduction system has paired sinus nodes and paired atrioventricular nodes. Electrophysiological studies were performed in two patients with right atrial isomerism. One patient had a delta wave on the surface electrocardiogram without tachycardia attacks. The other, who did not have manifest pre-excitation, had recurrent narrow QRS tachycardia. Electrophysiological studies suggested the presence of dual atrioventricular nodes. Only unidirectional atrioventricular or ventriculoatrial conduction was demonstrated for these dual atrioventricular nodes even after infusion of isoprenaline. It is suggested that unidirectional conduction may be a common property of the dual atrioventricular nodes in right atrial isomerism and that the absence of retrograde ventriculoatrial conduction protects the patients against tachycardia.

Atrioventricular Node↗
PubMed1995

Coumaphos intoxications mimic food poisoning.

Reports of food poisoning caused by pesticide-contaminated food are rare in the medical literature. In this paper, we report six patients who suffered food poisoning in two separate episodes in which the pesticide coumaphos was apparently misused as a food flavoring. These six patients presented not only the general manifestations of gastroenteritis, but also some unusual extraintestinal symptoms. These included cholinergic overactivity (miosis, urinary incontinence and hypersalivation) that led us to suspect organophosphate intoxication. This diagnosis was confirmed by serial changes in RBC cholinesterase and pseudocholinesterase activity, and by the presence of coumaphos in the contaminated food. Of the six patients, one was dead on arrival. Another patient developed progressive respiratory failure and required mechanical ventilation. The mortality rate among our cases was 16.7%. Since the coumaphos was apparently added to food during cooking, its toxic effects do not appear to be mitigated by heating. When food poisoning cases present with both gastroenteritis and unusual autonomic symptoms, the autonomic syndromes will aid in the diagnosis and management of these critically ill patients.

Adult↗