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Biomedical subjects

H W Louie

Publications and source records attributed to H W Louie.

11 recordsLinked to original sources
PubMed1999

Comparisons of genomic structures and chromosomal locations of the mouse aldose reductase and aldose reductase-like genes.

Aldose reductase (AR), best known as the first enzyme in the polyol pathway of sugar metabolism, has been implicated in a wide variety of physiological functions and in the etiology of diabetic complications. We have determined the structures and chromosomal locations of the mouse AR gene (Aldor1) and of two genes highly homologous to Aldor1: the fibroblast growth factor regulated protein gene (Fgfrp) and the androgen regulated vas deferens protein gene (Avdp). The number of introns and their locations in the mouse Aldor1 gene are identical to those of rat and human AR genes and also to those of Fgfrp and Avdp. Mouse Aldor1 gene was found to be located near the Cald1 (Caldesmon) and Ptn (Pleiotropin) loci at the proximal end of chromosome 6. The closely related genes Fgfrp and Avdp were also mapped in this region of the chromosome, suggesting that these three genes may have arisen by a gene duplication event.

Aldehyde Reductase↗
PubMed1996

MRI of pseudoaneurysm of a brachial venous coronary bypass graft.

Coronary artery bypass grafting (CABG) is being performed all over the world, with major success in the management of ischemic heart disease and angina pectoris. Complications of bypass grafting include partial or total graft reocclusion, and less common entities such as aneurysm or pseudoaneurysm formation. Noninvasive imaging procedures exist which can help include or exclude the presence of these unusual types of complications when mass-like abnormalities are seen on a chest X-ray following coronary artery bypass grafting. This case specifically illustrates the usefulness of ultrafast magnetic resonance imaging techniques in the evaluation and diagnosis of pseudoaneurysm formation at the site of coronary artery bypass graft.

Aged↗
PubMed1993

Pulmonary sequestration: 17-year experience at UCLA.

Pulmonary sequestration is a complex anomaly involving the pulmonary parenchyma and its vascularity. From 1975 to 1992, 10 cases have been treated at the UCLA Medical Center. The ages of the seven females and three males were bimodal, the median age of the seven children was 29 days (range 1 day-6 years); it was 32 years (range 28-39) for the three adults. One child was delivered by cesarean section for fetal distress and another was born at 29 weeks gestation. Symptoms included: recurrent pneumonia (5), respiratory distress (5), hemoptysis (2), stridor (1), and pleuritis (1). Chest radiographs were consistent with sequestration in seven patients and diaphragmatic hernia in another, but incorrectly diagnosed one diaphragmatic eventration and one pulmonary varix. Computed tomographs suggested sequestration in five patients, but mistakenly interpreted a pulmonary varix in one case. Angiography, ultrasonography, and magnetic resonance imaging were infrequent investigative studies and yielded variable results. All patients underwent thoracotomy and lobectomy without morbidity or mortality. Five had intralobar and five had extralobar sequestration. All adults had intralobar sequestration. Two had aberrant subdiaphragmatic arterial vessels. Eight had vessels originating from the descending thoracic aorta. Nine patients are asymptomatic at six months to 10 years follow up. The 29-week-old premature infant died 30 days postoperatively due to necrotizing enterocolitis. Pulmonary sequestration remains an uncommon entity. The radiologic investigations that provide the most information are the chest radiography and computed tomography. Definitive diagnosis is made at thoracotomy. Pulmonary sequestrations are resected with excellent results by the trained thoracic surgeon who is aware of the unusual vascular connections.

Academic Medical Centers↗
PubMed1993

Staged Zenker's diverticulectomy with cervical esophagostomy and secondary esophagostomy closure for treatment of massive diverticulum in severely debilitated patients.

Cricopharyngeal myotomy and diverticulectomy have become the standard therapy for the vast majority of patients with pharyngoesophageal diverticula. Potential complications from this approach, however, may be devastating in debilitated, elderly patients with massive Zenker's diverticula. Because of potentially fatal complications, we advocate a staged approach to treat debilitated patients with massive Zenker's diverticula. In the first stage, myotomy, diverticulectomy, and cervical esophagostomy are performed, and a gastric feeding tube is positioned through the esophagostomy. After recovery from pulmonary complications and nutritional improvement, the feeding tube is removed and the esophagostomy is closed. From 1987 to 1992, we treated five severely debilitated patients, four men and one woman with massive Zenker's diverticula, with this novel approach. Age of the patients averaged 80 years, range 58 to 93. All patients had symptoms of pulmonary aspiration requiring multiple hospitalizations for life-threatening pneumonia. Three patients had severe malnutrition associated with major weight loss and cachexia. All patients underwent first stage repair without morbidity or mortality. After an average of 7 weeks, patients had significant nutritional improvement and the esophagostomy was closed. Local wound care adequately treated one wound infection after esophagostomy closure. Although myotomy and diverticulectomy are safe procedures, a staged approach, diverticulectomy and cervical esophagostomy, followed by esophagostomy closure, is advocated for the elderly, severely debilitated patient with massive Zenker's diverticulum.

Aged↗
PubMed1992

The inferior epigastric arteries as coronary bypass conduits. Size, preoperative duplex scan assessment of suitability, and early clinical experience.

We are currently evaluating the inferior epigastric artery as an alternative arterial conduit for coronary bypass grafting. Fifty-seven inferior epigastric arteries were harvested from 47 adults. There were no differences in size between the right and left inferior epigastric arteries. Diameter was 2.5 to 3.5 mm proximally and 2 to 3 mm distally. Usable length was 6 to 16 cm (mean 11.2 +/- 0.25 cm). Grade I/IV atherosclerosis was found in one patient (2.1%). Duplex scanning was used for preoperative evaluation of the inferior epigastric arteries in 51 patients. In 21 patients the arteries were not harvested, in part because of duplex scan findings of small caliber or early bifurcation. In 30 patients the duplex findings could be compared with the surgical findings. The average length at operation was twice the length detected on duplex scan (11.2 cm versus 5.8 cm, p less than 0.001). There was a good correlation between diameter on duplex scan and that measured at operation (2.56 +/- 0.05 versus 2.62 +/- 0.07, p = not significant). Between December 1989 and May 1991, 38 patients (29 to 74 years, mean 56 years) received 42 inferior epigastric artery grafts. Proximal anastomoses were to the aorta in 17, to the vein graft hood in 20, or onto an internal mammary artery graft in 5. Distal anastomoses were to the left anterior descending artery in 2, the diagonal branch in 27, the marginal branch in 9, or the right coronary artery in 4. There were no early deaths. Complications included perioperative myocardial infarction in 1, deep sternal wound infection in 2, superficial infection at the harvest site of the inferior epigastric artery in 5, and reexploration for bleeding in 2. Because of its size and the low incidence of atherosclerosis, the inferior epigastric artery may evolve as an alternative arterial conduit for coronary bypass. Duplex scanning is a valuable noninvasive tool for preoperative evaluation of the artery's suitability. Long-term studies of patency of the inferior epigastric artery as a coronary bypass conduit are needed.

Abdominal Muscles↗
PubMed1991

Results of total cavopulmonary connection in the treatment of patients with a functional single ventricle.

Total cavopulmonary connection was proposed as a modification of the Fontan procedure that might have greater benefits than previous methods. To assess this procedure we reviewed case histories of 38 patients (aged 17 months to 30 years) who underwent Fontan procedures with cavopulmonary anastomoses between January 1987 and December 1989. The group included 32 patients with univentricular heart, 2 with pulmonary atresia and intact ventricular septum, 3 with tricuspid atresia, and 1 with hypoplastic left heart syndrome. One or more previous palliative procedures were performed in 34 patients, including 19 systemic-pulmonary shunts, 16 pulmonary artery bandings, 7 atrial septectomies/septostomies, 7 Glenn shunts, and 1 patent ductus arteriosus ligation. Preoperative hemodynamics showed a pulmonary artery pressure of 12 mm Hg (range 6 to 22 mm Hg), pulmonary-systemic flow ratio of 1.6 (range 0.37 to 3.0), left ventricular end-diastolic pressure 9 mm Hg (range 3 to 15 mm Hg), and systemic arterial oxygen saturation of 82% (range 67% to 94%). Concomitant with cavopulmonary connection, 13 patients underwent additional procedures, including 9 atrioventricular valve annuloplasties, 4 Damus-Stansel-Kaye procedures, and 2 resections of subaortic membranes. Modifying the Fontan procedure in this fashion was particularly useful in the management of 2 patients with pulmonary atresia and intact ventricular septum who had right ventricular-dependent coronary blood flow. Cavopulmonary anastomosis and atrial septectomy were performed in both patients, with resultant inflow of oxygenated blood to the right ventricle and coronary arteries. Excellent postoperative results were noted in each. Postextubation hemodynamics for the entire group included a mean right atrial pressure of 13 mm Hg (range 11 to 17 mm Hg), a mean left atrial pressure of 6 mm Hg (range 3 to 12 mm Hg), and a room air oxygen saturation of 96% (range 92% to 98%). Seven patients had pleural effusions, 3 required postoperative pacemaker placement, and 2 required reoperation for tamponade. A venous assist device was required in one patient on the second postoperative day, but the patient was weaned successfully within 24 hours. One early death (2.6%) occurred in a patient who had intractable ventricular fibrillation 2 days after operation. There was one late cardiac death (2.7%) caused by ventricular failure and one late noncardiac death. These results demonstrate that total cavopulmonary connection provides excellent early definitive treatment, with low morbidity and mortality, for a variety of complex congenital heart lesions.

Adolescent↗
PubMed1991

Ischemic cardiomyopathy. Criteria for coronary revascularization and cardiac transplantation.

Because of the shortage of donor hearts, 16 (33%) of 48 patients with ischemic cardiomyopathy died awaiting transplantation. Determining factors that predict effective coronary revascularization and identifying patients who may benefit from revascularization is crucial. From 1984 to 1990, 207 ischemic cardiomyopathy patients were evaluated for heart transplantation; 131 were accepted (83 transplanted), 54 were not accepted, and 22 were revascularized (19 underwent bypass graft surgery and three underwent percutaneous transluminal coronary angioplasty). Four bypass patients failed early (less than or equal to 30 days, three deaths and one urgent heart transplant) and two late deaths (greater than or equal to 1 year) occurred. Overall mortality was 27%. Three-year survival of revascularized and transplanted patients was 72 +/- 10% and 73 +/- 6%, respectively. Successfully revascularized patients had preoperative ejection fraction, left ventricular end-diastolic dimension, and New York Heart Association functional class of 26 +/- 9%, 68 +/- 3 mm, and 3.9 +/- 0.4, respectively, compared with 36 +/- 9% (p less than 0.05), 64 +/- 6 mm (p = NS), and 1.2 +/- 0.4 (p less than 0.05) after revascularization. Preoperative ejection fraction of patients failing revascularization was 15 +/- 4% (p = NS compared with successful revascularization), and left ventricular end-diastolic dimension was 81 +/- 4 mm (p less than 0.05). Preoperative positron emission tomography imaging myocardial blood flow and glucose metabolism was performed in 12 patients: 10 patients with scans predicting reversible ischemia were successfully revascularized, and two patients with negative scans had failed revascularization.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMedDate not supplied

New technique of vascularization of the trachea and bronchus for lung transplantation.

Ischemic necrosis is implicated as a major cause of dehiscence and stenosis of the airway anastomosis in double and single lung transplants. A new surgical technique to maintain systemic arterial blood flow to the transplanted airways by preserving the donor tracheobronchial arterial circulation was investigated. In a primate model, the tracheobronchial arterial circulation to the transplanted airways was maintained by inclusion of an aortic segment with its bronchial arteries and tracheal collaterals in continuity with the lung bloc. The aortic segment, from just proximal to the left subclavian artery to the level of the pulmonary hilum, was vascularized by anastomosis of the subclavian artery to the recipient left subclavian artery or ascending aorta. Double lung transplantation was performed in three baboons; two survived 48 hours, and one was killed at 30 days. One baboon with a left single lung transplant was killed at 30 days, and one baboon with a right single lung transplant survived 22 days. Angiograms obtained 14 days after transplantation showed patent subclavian anastomoses and aortic segments. Postmortem examination revealed patent subclavian anastomoses without thrombi in the aortic segments. There was no airway necrosis, dehiscence, or stenosis. Tracheal and bronchial anastomoses of surviving animals were healed. Histologic examination revealed typical respiratory tissues without ischemia or necrosis. Radiographic examination of aortic segments injected with lead oxide showed patent bronchial arteries extending along the donor trachea and bronchi and to the anastomotic sites. These experimental studies demonstrate that this technique maintains the donor tracheobronchial arterial circulation and may improve tracheal and bronchial anastomotic healing.

Animals↗
PubMedDate not supplied

Immunohistochemical analysis of accelerated graft atherosclerosis in cardiac transplantation.

HHT was performed between minimally genetic mismatched inbred strains of rats. There was no evidence of rejection and immunosuppressive therapy was not instituted. Immunohistochemical analysis using peroxidase conjugated monoclonal anti-rat ASMA of cardiac arterioles in which AGAS developed revealed a decreased peroxidase signal. The data suggest that modulation of actin expression in subintimal cells of cardiac arterioles may play a critical role in the pathologic development of AGAS.

Animals↗
PubMedDate not supplied

Digestion of food samples for total mercury determination.

A method of digestion by using a mixture of hydrochloric, nitric, and sulfuric acids has been developed for the determination of total mercury in a wide range of food samples. Good recoveries of mercury were obtained from NBS (National Bureau of Standards) Albacore Tuna and from food samples spiked with inorganic mercury. A detection limit of 0.01 microgram mercury/g can be obtained.

Animals↗