Biomedical subjects

M H Wu

Publications and source records attributed to M H Wu.

At least 91 records · Page 5Linked to original sources

PubMed1999

Early detection of unilateral occlusion of duplicated uterus with ipsilateral renal anomaly in young girls: two case reports with three-dimensional sonography.

Early detection of unilateral occlusion of duplicated uterus with ipsilateral renal anomaly is very rare and difficult. We present two cases using three-dimensional (3D) sonography as a noninvasive, comprehensive and effective method in the early detection of this syndrome in the young girls. The two young, unmarried girls had irregular abdominal discomfort and pain during the recent few years. Series traditional study showed pelvic lesions, but failed to recognized the definite cause. With 3D sonography, we demonstrated the rare congenital anatomic relationships and gave the optimal management. The girls recovered soon and had uneventful OPD follow-up. Application of 3D sonography in the suspected young girls avoids unnecessary examinations and invasive interventions, decreases the morbidity and improves their quality of life.

Abnormalities, Multiple↗

PubMed1999

Tricuspid atresia with persistent truncus arteriosus.

The association of tricuspid atresia and persistent truncus arteriosus is a very rare congenital anomaly. We report a newborn with a prenatal diagnosis of tricuspid atresia, in whom associated type II persistent truncus arteriosus was found by postnatal echocardiography. The patient had mild cyanosis and developed heart failure soon after birth. Balloon septostomy was performed to enlarge the interatrial communication. However, her condition rapidly deteriorated and she died of sepsis and heart failure at the age of 14 days.

Female↗

PubMed1999

Differential pulmonary flow in hypoplastic left heart syndrome.

We report a case of hypoplastic left heart syndrome associated with restrictive interatrial communication and partial anomalous pulmonary venous connection via a right lower pulmonary vein draining to the inferior vena cava. We found unequal pulmonary artery pressure and different pulmonary artery structure, with the right pulmonary artery being lower in pressure and more tortuous and dilated in its peripheral branches than the left. This was attributed to the variant degrees of pulmonary venous obstruction. The left pulmonary venous return was severely obstructed by the restrictive interatrial communication, whereas the anomalous right lower pulmonary vein drained into the inferior vena cava, with less obstruction. To the best of our knowledge, there has never before been a report of differential pulmonary flow associated with a partial anomalous pulmonary vein, in a case of hypoplastic left heart syndrome.

Echocardiography, Doppler, Color↗

PubMed1999

Pulmonary vein atresia with Shone's anomaly in an infant: a case report.

We report a case of individual pulmonary vein atresia associated with multiple levels of left heart obstruction, including aortic coarctation, valvular aortic stenosis, and parachute mitral valves with stenosis. The diagnosis of pulmonary vein obstruction is likely to be missed in patients who also have other left heart obstructive diseases, since the latter usually dominates the clinical presentation. We diagnosed the existence of individual pulmonary vein atresia preoperatively via cardiac catheterization. The pulmonary artery angiograms revealed back and forth motion of the dye with no visualization of either a capillary or venous phase on the lesion side. The pulmonary capillary wedge pressure was unevenly elevated and highest on the lesion side. The results were later confirmed by operation and autopsy. Thus, selective pulmonary artery catheterization and angiography remains a good diagnostic tool to rule out the existence of pulmonary vein obstruction in cases which have multiple levels of left heart obstruction.

Aortic Coarctation↗

PubMed1999

Lack of evidence for a polymorphism at codon 160 of human O6-alkylguanine-DNA alkyltransferase gene in normal tissue and cancer.

O6-benzylguanine (BG) is a potent, specific inactivator of the DNA repair protein O6-alkylguanine-DNA alkyltransferase (AGT), which enhances sensitivity to nitrosoureas in cells and tumor-bearing animals. BG is presently undergoing clinical trials for development as an agent to enhance the therapeutic index of alkylating agent chemotherapy. It has been reported that a polymorphism exists in the human agt gene, with about 15% of the Japanese population having arginine at codon 160 instead of glycine on the polypeptide (Y. Imai et al., Carcinogenesis, 16: 2441-2445, 1995). The resultant mutant AGT protein is equally effective against both methylated DNA as compared with wild type protein. However, this mutant AGT protein was less sensitive to inactivation by BG with a 20-fold increase in the ED50 value. This observation raised the possibility that a subpopulation of patients may be resistant to BG due to a single base change. We have demonstrated that this alteration also reduces the sensitivity to O6-benzyl-8-oxoguanine, an equally potent, yet much longer-lived human metabolite of BG. To test the possibility that this germ-line mutation of the agt gene might explain resistance to BG and O6-benzyl-8-oxoguanine of patients on our Phase I clinical trials, we evaluated the DNA from lymphocytes of 18 patients. The G160R mutation was not found in any of the 18 patients. To determine the frequency of this mutation in the United States population, DNA from 181 healthy individuals were investigated and, again, the mutation was not observed in this cohort. Therefore, if the mutation exists, it is in statistically <1.6% of the United States noncancerous population. To investigate the possibility that this mutation might be somatic, we evaluated genomic DNA samples from 94 human primary cancers of four different histological subtypes (brain, colon, esophageal, and head and neck). Again, none were found to have the G160R mutation.

Animals↗

PubMed1998

Transarterial approach of the pulmonary artery in anatomically corrected malposition of the great arteries by manipulating a catheter inverted with balloon floating maneuver.

We describe two neonates with anatomically corrected malposition of the great arteries (ACM). A 1-day-old female newborn, who had the salient clinical findings of Goldenhar syndrome, behaved like a patient with the tetralogy of Fallot. The cardiac malformations included ACM, perimembranous inlet and outlet ventricular septal defect with tricuspid valve straddling, conoventricular septal malaligement, bilateral cori without aortic-mitral continuity, pulmonary stenosis at subvalvular, valvular, and supravalvular levels, and bicuspid semilunar valves. After the procedure of left Blalock-Taussig shunt at 3 months of age, cyanosis was alleviated. The other 1-month-old male newborn, who presented with prolonged feeding, tachypnea and tachycardia, likened to a patient with the hypoplastic left heart syndrome. He had a combination of ACM, mitral stenosis, hypoplastic left atrium and left ventricle, a restrictive patent foramen ovale, ventricular septal defect, subaortic conus without aortic-mitral continuity, subaortic stenosis, and a narrow ascending aortic root. Rashkind balloon atrioseptostomy was done with limited success. He survived a Norwood procedure. Transarterial entry of the catheter, which was inverted with the aid of balloon floating maneuver, to hook the retro-aortic pulmonary artery in ACM is recommended.

Angiography↗

PubMed1998

Evidence for circulating bone marrow-derived endothelial cells.

It has been proposed that hematopoietic and endothelial cells are derived from a common cell, the hemangioblast. In this study, we demonstrate that a subset of CD34(+) cells have the capacity to differentiate into endothelial cells in vitro in the presence of basic fibroblast growth factor, insulin-like growth factor-1, and vascular endothelial growth factor. These differentiated endothelial cells are CD34(+), stain for von Willebrand factor (vWF), and incorporate acetylated low-density lipoprotein (LDL). This suggests the possible existence of a bone marrow-derived precursor endothelial cell. To demonstrate this phenomenon in vivo, we used a canine bone marrow transplantation model, in which the marrow cells from the donor and recipient are genetically distinct. Between 6 to 8 months after transplantation, a Dacron graft, made impervious to prevent capillary ingrowth from the surrounding perigraft tissue, was implanted in the descending thoracic aorta. After 12 weeks, the graft was retrieved, and cells with endothelial morphology were identified by silver nitrate staining. Using the di(CA)n and tetranucleotide (GAAA)n repeat polymorphisms to distinguish between the donor and recipient DNA, we observed that only donor alleles were detected in DNA from positively stained cells on the impervious Dacron graft. These results strongly suggest that a subset of CD34+ cells localized in the bone marrow can be mobilized to the peripheral circulation and can colonize endothelial flow surfaces of vascular prostheses.

Animals↗

PubMed1998

Clinical implications of isolated double aortic arch and its complex with intracardiac anomalies.

From July 1, 1989 to June 30, 1996, a total of six patients, four male and two female, with double aortic arch (DAA) were registered. They aged 16 days to 6.5 years. There were two patients with isolated DAA, and four complicated with intracardiac anomalies. All six patients presented respiratory distress and feeding problem early in life. However, cyanosis, owing to decreased pulmonary blood flow, predominated the clinical picture in each patient having DAA intricated with tetralogy of Fallot (TOF) and pulmonary stenosis, TOF with absent pulmonary valve syndrome, and type II-A tricuspid atresia. DiGeorge syndrome was documented in one patient with TOF and pulmonary stenosis. Expiratory wheezing was remarkable in the patient with TOF and absent pulmonary valve syndrome. Mild cyanosis and heart failure was noted in one patient with ventricular septal defect (VSD), and bicuspid pulmonary valve with mild valvular stenosis. Barium esophagogram showed indentations on esophagus in five patients. Echocardiography was yielding in three infants. Four patients, two isolated and two complex DAA, survived the surgical division of the smaller left aortic arch. One-stage and two-stage operation was performed in patients having DAA intricated with VSD and TOF, respectively. The other two patients with complex DAA remained in close observation owing to the tolerance of symptoms related to intracardiac anomalies.

Aorta, Thoracic↗

PubMed1998

Evidence for the ability of nucleophosmin/B23 to bind ATP.

By taking advantage of its ability to be retained by ATP-agarose, we have demonstrated that nucleophosmin/B23 is capable of binding ATP. The specificity of the binding was confirmed by the absence of significant binding to AMP-agarose and by its loss when nucleophosmin/B23 in nuclear extracts was preincubated with ATP. Preincubation of the nuclear extracts with other ribonucleotide triphosphates (GTP, CTP, UTP) did not compete for the binding of nucleophosmin/B23 to ATP-agarose. The purified recombinant nucleophosmin/B23 was also able to be retained by ATP-agarose. The Kd for binding of ATP to the purified recombinant nucleophosmin/B23, on the basis of retention on a nitrocellulose membrane, was 86.5+/-8.3 microM; the number of binding sites was 0.68 per nucleophosmin/B23 protein molecule. To determine the possible ATP-binding site of nucleophosmin/B23, various deletion clones including the two mutants in which the putative ATP-binding sequence had been deleted were constructed. Deletion of the portions of the molecule (residues 83-152 and 185-240) had little effect on the ATP binding. The C-terminal deleted mutant (residue 242 to the C-terminus deleted) lost most of its ability to be retained by ATP-agarose and to bind [alpha-32P]ATP on a nitrocellulose membrane. The results indicate that the C-terminal portion (residues 242-294) contains the essential ATP-binding site of nucleophosmin/B23.

Adenosine Triphosphate↗

PubMed1998

Usefulness of electron beam computed tomography in children with heterotaxy syndrome.

Children with heterotaxy syndrome frequently have complex cardiac and noncardiac malformations requiring detailed diagnostic evaluation for management planning. Direct delineation of these structures by electron beam computed tomography (EBCT) is validated as a means of diagnosis. From July 1995 to March 1997, 32 patients (16 girls, 16 boys) with clinically impressed heterotaxy syndrome were enrolled in this study. After evaluation by echocardiography, EBCT studies were performed. Interpretation of cardiac anomalies was performed by sequential analysis based on these cross-sectional images. The diagnoses were subsequently confirmed by angiocardiography and surgical findings. Twenty-eight patients had bilateral trifurcated bronchi, and most of these (24 of 28) did not have a spleen. Four patients had bilateral bifurcated bronchi, 2 patients had polysplenia, and the other 2 patients had a lobulated single spleen. We found that laterality could be identified by EBCT in all patients. Comparison of diagnostic yield between echocardiography, catheterization, and EBCT showed that EBCT is superior to echocardiography and catheterization in demonstration of pulmonary venous anatomy and presence of a very small rudimentary ventricle. In addition, associated visceral, bronchopulmonary, mediastinal, and intracardiac anomalies could all be clearly delineated by EBCT at the same time. Thus, EBCT is a promising complementary modality for an overall understanding of heterotaxy syndrome.

Abnormalities, Multiple↗

PubMed1998

Apparent blood stream origin of endothelial and smooth muscle cells in the neointima of long, impervious carotid-femoral grafts in the dog.

The purpose of this study was to determine whether endothelial and smooth muscle cells originating from the blood stream contribute to the endothelialization of impervious, small-caliber, long Dacron grafts used as extraanatomical bypasses in dogs. We implanted silicone-rubber-coated, permanently impervious grafts 64 to 77 cm long and 6 mm in diameter, made of externally supported knitted Dacron as unilateral carotid-femoral bypasses with distal femoral arteriovenous fistulae in 10 dogs for 3 months; sides were alternated between cases. Subjects received 162 mg/day of aspirin, and its effectiveness on platelet aggregation (PA) was evaluated and expressed as a PA score. Graft healing was studied by stereomicroscopy with silver nitrate staining, by light microscopy with hematoxylin-eosin and immunocytochemical staining for endothelial and smooth muscle cells, and by scanning and transmission electron microscopy. Five grafts were patent for 3 months and could be included in the healing study; the five occluded grafts thrombosed within 14 days. Although there was no transinterstitial tissue ingrowth from perigraft tissues into the impervious Dacron grafts, scattered islands of endothelial cells were conclusively demonstrated on graft flow surfaces 3 months after implantation. Average endothelial-like cell coverage of the flow surfaces was 15.6% +/- 3.8%, and alpha-actin-positive smooth muscle cells and microvessels were found beneath some of the endothelial islands. These findings suggest that blood stream-derived endothelial and smooth muscle cells play a role in the healing of the inner wall of Dacron grafts in the dog.

Animals↗

PubMed1998

Early flow surface endothelialization before microvessel ingrowth in accelerated graft healing, with BrdU identification of cellular proliferation.

The purpose of this report was to determine if flow surface endothelialization could precede microvessel ingrowth from the perigraft area in porous Dacron grafts, by using an accelerated graft healing model with short implant periods. Dacron grafts were implanted in the abdominal aorta of 22 dogs and wrapped in autogenous inferior vena cava (IVC), which provided excellent conditions for extramural angiogenesis, microvessel development, and ingrowth toward the graft. Retrieval times were 7 days (n = 4), 8 days (n = 5), 9 days (n = 4), 10 days (n = 3), 11 days (n = 4) and 12 days (n = 3) postoperatively. Graft surfaces were evaluated for thrombus coverage, cell coverage, and the number of micro-ostia. Components and cellular types in the graft wall and on the surface were studied and characterized with H&E, histochemical, and immunocytochemical staining. BrdU labeling was also used, to identify the areas where cells were actively proliferating. All grafts were patent. Although the degree of IVC/graft attachment varied, isolated islands of endothelial-like cells were found at the midgraft areas at each time period, and immunocytochemically confirmed as endothelial cells. There were two healing patterns: (1) surface endothelialization before microvessel/tissue ingrowth from the perigraft areas, and (2) surface endothelialization with full wall microvessel and tissue presence. Surface endothelialization was observed before perigraft tissue ingrowth, indicating that fallout healing is an independent source of endothelialization for porous grafts.

Animals↗

PubMed1998

The effect of flow shear stress on endothelialization of impervious Dacron grafts from circulating cells in the arterial and venous systems of the same dog.

The purpose of this report was to study effects of shear force and hemodynamic conditions that influence fallout healing in the arterial and venous systems of the same dog. Knitted Dacron grafts made impervious by a 1.5 mm thick coat of silicone rubber bonded to the external surface were implanted for 4 weeks during the same surgery in the descending thoracic aorta (DTA), abdominal aorta (AA) and inferior vena cava (IVC) of each of five dogs. Flow rates were measured during surgery and shear stresses calculated with the Hagen-Poiseuille formula. Full-wall thickness longitudinal tissue sections were embedded in resin and stained with hematoxylin and eosin for light microscopy, and in paraffin for immunocytochemistry studies with Factor VIII/von Willebrand factor, smooth muscle alpha-actin, collagen IV, laminin, and proliferating cell nuclear antigen. Scanning electron microscopy and transmission electron microscopy studies were also performed. AgNO3 was used to determine percentage of endothelial-like cell coverage on the flow surface. All grafts were patent, without hematoma or seroma. Endothelial-like cell coverage was highest in the IVC grafts and lowest in the DTA. Shear stress and flow velocity were significantly lower in IVC grafts than DTA and AA. Proliferating cell nuclear antigen indicated extensive cellular proliferation in the intima and in the interstices of the inner portion of the graft wall. The degree of fallout healing in knitted Dacron grafts made impervious by an external coat of silicone rubber varies inversely with the sheer force of blood flow in these grafts.

Animals↗

PubMed1998

Effect of skeletonizing dissection on the internal thoracic artery.

BACKGROUND: Skeletonization of the internal thoracic artery (ITA) produces greater length for coronary bypass grafting. We studied the effect of skeletonization on the morphology, histology, and tissue viability of the ITA wall. METHODS: Six mongrel dogs underwent unilateral ITA dissection; the contralateral ITA was the control. Study periods were 3 weeks (n=3) and 12 weeks (n=3). At sacrifice, the entire anterior chest wall was removed and dynamically fixed with formalin. Extensive histologic comparisons were performed on three tissue blocks taken from each ITA, 2, 8, and 24 cm from their origin. RESULTS: Flows at the end of the study were comparable to measurements taken during operation, immediately after skeletonization. Grossly, the ITA wall was not injured by skeletonization and there was no adventitial hematoma or bleeding from the sealed branch ends. Microscopic observations showed intact, normal wall structures. Histologic data showed no major significant difference between controls and skeletonized ITAs. CONCLUSIONS: Careful skeletonizing dissection is not detrimental to the integrity of ITAs, which justifies their use for myocardial revascularization.

Animals↗

PubMed1998

The role of three-dimensional ultrasonographic images in ovarian measurement.

OBJECTIVE: To determine whether three-dimensional ultrasonography can increase the ability to evaluate the ovary and follicles, especially in women with polycystic ovary disease (PCOD). DESIGN: Prospective clinical study. SETTING: University hospital endocrine and infertility center. PATIENT(S): Sixty-six patients undergoing routine gynecologic evaluation were divided into two groups: the normal control group consisted of 22 patients, and there were 44 patients with PCOD. INTERVENTION(S): Three-dimensional ultrasonography was performed to store and document whole volumes of the ovaries for evaluation. MAIN OUTCOME MEASURE(S): Three perpendicular planes of bilateral ovaries are rotatable to obtain the largest dimensions. The three-dimensional volume was measured using the trapezoid formula. RESULT(S): The ovaries of the patients with PCOD were larger in size, area, and volume than those of normal controls. CONCLUSION(S): Stroma and volume determinations can be obtained more accurately by three-dimensional images than by traditional ultrasonography. Three-dimensional ultrasonography not only facilitates noninvasive evaluation and volume calculation but also completes the examination in a short time without increasing patient discomfort.

Adult↗

PubMed1998

The expression of soluble intercellular adhesion molecule-1 in endometriosis.

OBJECTIVE: To investigate the association between concentrations of soluble intercellular adhesion molecule-1 (ICAM-1) and interferon-gamma (IFN-gamma) with regard to the severity of endometriosis. DESIGN: Cross-sectional study. SETTING: Infertility unit in a university hospital. PATIENT(S): Seventy-one infertile patients who underwent laparoscopic evaluation were divided into two groups: 36 patients with endometriosis served as cases, and 35 patients without endometriosis served as control subjects. INTERVENTION(S): Peripheral blood and peritoneal fluid (PF) were collected from these patients during laparoscopic examination. MAIN OUTCOME MEASURE(S): Quantitative determination of levels of human ICAM-1 and IFN-gamma was performed with the use of an ELISA. The data were evaluated by Student's t-test, analysis of variance, and regression analysis. RESULT(S): Significantly elevated levels of soluble ICAM-1 were found in the sera of patients with endometriosis, especially those with advanced stages of the disease. Decreased IFN-gamma levels, which were negatively correlated with serum levels of soluble ICAM-1, also were noted in the PF of patients with endometriosis. CONCLUSION(S): The increased serum levels of ICAM-1 found in patients with endometriosis may indicate the presence of an active disease process. Further, the increased levels of soluble ICAM-1 in peripheral blood were inversely correlated with the concentrations of IFN-gamma in PF. The increased levels of soluble ICAM-1 in plasma may be associated with an immunologic feedback response that blocks further infiltration of immune cells. These findings may be of value in the diagnosis and evaluation of endometriosis.

Adult↗

PubMed1998

Electrophysiological mechanisms for the antiarrhythmic activities of naloxone on cardiac tissues.

It has been reported that naloxone, an opioid antagonist, has antiarrhythmic activity in vivo. In Langendorff perfused rat hearts, we found that ischemia-reperfusion-induced ventricular tachyarrhythmia reverted to normal sinus rhythm after the treatment with naloxone (3 approximately 10 microM). The method of voltage and current clamp were used to study the underlying mechanism of its antiarrhythmic activity on isolated cardiac myocytes. In isolated rat ventricular and in guinea-pig and human atrial myocytes, naloxone prolonged the action potential duration reversibly. In rat ventricular myocytes, naloxone (1 approximately 30 microM) inhibited sodium current (I(Na)), transient outward potassium current (I(to)), and calcium current (I(Ca)). On the contrary, the addition of naloxone significantly increased inward rectifier potassium current (I(K1)). For the effect on I(Na), naloxone did not shift the inactivation curve of I(Na) but retarded the I(Na) recovery rate from inactivation state. Naloxone suppressed I(to) with a significant left-shift of the inactivation curve, however, the time course of I(to) recovery from inactivation was not affected. In guinea pig atrial myocytes, naloxone (10 microM) decreased the delayed rectifier K+ current (IK). These results show that naloxone exert various extent of inhibition on I(Na), I(to), IK and I(Ca). The prolongation of cardiac action potential is related to the inhibition of I(to) and IK. The antiarrhythmic activity of naloxone is more closely related to the inhibition of Na+ and K+ currents rather than the blockade of myocardial opioid receptors.

Action Potentials↗

PubMed1998

Supraventricular tachycardia in patients with right atrial isomerism.

OBJECTIVES: To clarify the prevalence and mechanism of supraventricular tachycardia in patients with right atrial isomerism. BACKGROUND: Paired SA and dual atrioventricular (AV) nodes have been described in patients with right atrial isomerism. However, the clinical significance remains unclear. METHODS: From 1987 to 1996, a total of 101 patients (61 male, 40 female) and four fetuses were identified with right atrial isomerism. The diagnosis of supraventricular tachycardia exclude the tachycardia with prolonged QRS duration or AV dissociation, and primary atrial tachycardia. RESULTS: The median follow-up duration was 38 months (range 0.2-270 months). Supraventricular tachycardia was documented in 25 patients (24.8%) and one fetus (25%) (onset age ranged from prenatal to 14 years old; median 4 years old). Actuarial Kaplan-Meier analysis revealed that the probability of being free from tachycardia was 67% and 50% at 6 and 10 years of age, respectively. These tachycardias could be converted by vagal maneuvers in one, verapamil in seven, propranolol in four, digoxin in two, procainamide in one, and rapid pacing in five. Spontaneous conversion was noted in six (including the fetus). Seven cases had received electrophysiological studies. Reciprocating AV tachycardia could be induced in five and echo beats in one. The tachycardia in three patients was documented as incorporating a posterior AV node (antegrade) and an anterior or a lateral AV node (retrograde). Two of them received radiofrequency ablation. Successful ablation in both was obtained by delivering energy during tachycardia, aimed at the earliest retrograde atrial activity and accompanied by junctional ectopic rhythm. The patient with echo beats developed tachycardia soon after operation. CONCLUSIONS: Supraventricular tachycardia is common in patients with right atrial isomerism and can occur during the prenatal stage. Drugs to slow conduction through the AV node may help to terminate the tachycardia. Radiofrequency ablation is a safe and effective treatment alternative to eliminate tachycardia.

Actuarial Analysis↗