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Biomedical subjects

J H Lu

Publications and source records attributed to J H Lu.

At least 19 recordsLinked to original sources
PubMed2003

Rescue of hepatitis A virus from cDNA-transfected but not virion RNA-transfected mouse Ltk- cells.

Hepatitis A virus (HAV) has stringent replication requirements and a restricted host-range. Mouse Ltk- cells do not support growth of HAV upon infection or transfection of virion RNA. However, low levels of HAV were rescued from Ltk- cells transiently transfected with its infectious cDNA. Ltk- stable transfectants that expressed HAV antigens and produced infectious HAV were selected and termed Ltk-pJH15 cells. After a few serial passages, HAV became undetectable in the Ltk-pJH15 cells. Multiple rounds of single cell cloning of HAV antigen positive Ltk-pJH15 cells resulted in the isolation of clone E8 that produced higher levels of HAV for at least 5 passages. HAV produced in E8 cells was similar to the parental virus as shown by infectivity assays. Luciferase assays using a bi-cistronic construct containing the HAV 5' noncoding region showed similar levels of HAV IRES-dependent translation in Ltk- and Ltk-pJH15 cells, which suggested that HAV IRES-dependent translation was not a limiting factor for HAV growth in these cells. The availability of the Ltk-pHJ15 cells will allow the identification of cellular factors required for HAV growth, which could lead to the development of a mouse model to study pathogenesis of HAV.

Animals↗
PubMed2001

Absence of mutations in human ubiquitin fusion-degradation protein gene in tetralogy of Fallot.

Congenital defects in human chromosome 22q11 deletion syndromes are associated with the 3rd and 4th pharyngeal pouch during fetal development. In the cardiovascular system, these disorders are usually apparent as conotruncal heart defects and aortic arch anomalies. UFD1L, a gene that is downregulated in dHAND-deficient mice, expressed in the mouse embryo at the branchial arch and mapped to human chromosome 22q11, has recently been strongly suspected to be responsible for the phenotypes expressed in 22q11 deletion syndromes. Its putative causal role in relevant congenital cardiovascular malformations was studied by gene dosage analysis, mutation screening and sequence analyses. Sixty cases of tetralogy of Fallot with no detectable chromosome deletion at 22q11 or 10p13 were examined, including 51 cases of simple tetralogy of Fallot, and 9 cases of tetralogy of Fallot with pulmonary atresia. None of these patients revealed deletion limited to a portion of the UFD1L gene. Although mobility shift was found by heteroduplex analysis in 24 cases at exon 4 and flanking sequences, further sequence analysis demonstrated only two silent nucleotide variations and a single nucleotide polymorphism in intron 4. Our data suggest that, although the UFD1L gene is mapped to 22q11 and is expressed during early murine development at both cardiac and cranial neural crests, it is not responsible for the majority of tetralogy of Fallot cases in humans.

Adaptor Proteins, Vesicular Transport↗
PubMed2001

Spectrophotometric determination of polyacrylamide in waters containing dissolved organic matter.

Using polyacrylamide (PAM) to reduce soil erosion in irrigated land has increased rapidly in recent years. A simple and reliable method to measure the PAM concentration in waters containing dissolved organic matter (DOM) is of great importance in assessing the fate and efficiency of PAM application. In this research, an analytical method to determine the PAM concentration of waters with correction for DOM interference was developed and tested. The method is based on a combination of determining the total concentration of amide groups by the N-bromination method (NBM) and determining the DOM content spectrophotometrically. The total concentration of amide groups of both PAM and DOM was determined by NBM at 570 nm. The DOM moiety, which is proportional to DOM concentration, was determined by spectrophotometry using a UV 254-nm wavelength. The actual PAM concentration of a water sample (soil extract containing PAM in this study) was obtained from NBM readings subtracted by the interferential DOM contribution using a correction curve. Analysis of PAM in two soil-water samples showed that the recoveries ranged from 94 to 100.3% for the 2 mg/L PAM sample and from 98.4 to 101.4% for the 10 mg/L PAM sample with various DOM concentrations. The coefficients of variation were <6% in all cases.

Acrylic Resins↗
PubMed2001

Chromosome 22q11 microdeletion in conotruncal heart defects: clinical presentation, parental origin and de novo mutations.

Using genotype analysis and multiplex quantitative polymerase chain reaction (PCR), chromosome 22q11 deletions were examined in 252 patients with syndromic or isolated conotruncal heart defect. Of these patients, 19 (7.5%) were found to be hemizygous for chromosome 22q11. Parental origin of the deleted chromosome was determined in 16 cases: one patient (6.3%) inherited a deleted chromosome 22 from his mother; all the others (93.7%) consisted of de novo mutations. One-third (5/15) of the de novo 22q11 deletions were of paternal origin and the remainder derived maternally. These results lend further support to our current knowledge of chromosome 22q11 microdeletion syndromes and their implications for the genetic counseling of individuals diagnosed with conotruncal heart defects. Possible mechanisms for gender-biased parental origin are discussed.

Adolescent↗
PubMed2001

Adsorption of chloroacetanilide herbicides on soil (I). Structural influence of chloroacetanilide herbicide for their adsorption on soils and its components.

Adsorption of chloroacetanilide herbicide acetochlor, alachlor, metolachlor and propachlor on soils and soil components was determined, and the structural differences of these herbicides were used to explain the order of sorptivity. Adsorption isotherms for all herbicide-soil combinations conformed to the Freundlich equation, and Ki increased with increasing soil organic carbon content. Kd on soil humic acid was greater than that on clay, but association of humic acid with clay reduced the overall adsorption. On all soils and soil humic acids, herbicide adsorption decreased in the order: metolachlor > acetochlor > propachlor > alachlor. On Ca(2+)-montmorrilonite, the order changed to metolachlor > acetochlor > alachlor > propachlor. FT-IR spectra of herbicide-clay or herbicide-humic acid-clay mixtures showed that H-bonding and charge transfer were the primary interaction pathways between these compounds and the surface of clay or humic acids. The different moieties attached to 2-chloro-acetanilide and their unique arrangement may have influenced the binding mechanisms and thus the sorptivity of these herbicides. This study indicates that the structural difference of pesticides in the same classes may be used as a molecular probe to obtain a better understanding of sorption mechanisms of pesticides on soil.

Acetamides↗
PubMed2001

Down-regulation of four arsenic antagonists on apoptosis and telomerase activity induced by arsenic trioxide in three myelocytic leukemia cell lines.

AIM: To investigate regulative effects of thiol reagents, N-acetyl-l-cysteine (NAC) and natrii dimercaptosussinas (NDMS), catalase (CAT), and calcium chelator 2-[(2-bis-[carboxymethyl]-amino-5-methyl-phenoxy)-met]-6-methoxy-8-bis-[carboxy-methyl]-aminoquinoline (Quin 2) on apoptosis and telomerase activity induced by arsenic trioxide (As2O3) in three myelocytic leukemia cell lines. METHODS: Flow cytometry was used to examine apoptosis and a PCR ELISA kit was used to detect telomerase activity. RESULTS: As2O3 induced about 40 % - 60 % of apoptosis in NB4, K562, and HL-60 cells at the concentration of 0.6, 2.7, and 8.1 micromol/L respectively, as well as down-regulated telomerase activities in three cell lines. NAC 4 mmol/L, NDMS 200 micromol/L, CAT 80 kU/L, and Quin 2 20 micromol/L could down-regulate apoptosis variously induced by As2O3. NAC and CAT alone could decline telomerase activity in three cell lines and further decline telomerase activities that had been decreased by As2O3, whereas Quin 2 antagonized the decline in K562 and HL-60 cells. CONCLUSION: Thiol activity loss, free radical alteration, intracellular calcium changes, and decline of telomerase activity might be involved in As2O3-induced apoptosis. NAC, NDMS, CAT, and Quin 2 antagonized in some extent the effect of As2O3 on the three tested cell lines.

Acetylcysteine↗
PubMed2001

[Studies on chemical constituents from Buddleja lindleyana Fert].

OBJECTIVE: To study the chemical constituents of Buddleja lindleyana. METHOD: Separation by chromatographic methods and identification by spectral analysis. RESULT: Seven compounds vanillic acid, daidzein octacosanoic acid, beta-sitosterol-3-O-beta-D-glucopyranoside, stigmasterol-3-O-beta-D-glucopyranoside, alpha-spinasterol-3-O-beta-D-glucopyranoside, betulin acid were isolated. CONCLUSION: All the compounds were obtained from this plant for the first time.

Buddleja↗
PubMed2000

Positron emission tomography for the assessment of myocardial viability in Kawasaki disease using different therapies.

13N-ammonia and 18F-fluorodeoxyglucose positron emission tomography (PET) of the heart were performed on 30 children with a history of Kawasaki disease. The results indicated PET abnormalities in 61.1% of patients during the acute and subacute stages and in 41.2% of patients in the convalescent stage of Kawasaki disease. Two-dimensional echocardiography and coronary angiography could not predict the myocardial viability and perfusion as well as PET. Different therapies during the acute stage of the disease did not effectively prevent myocardial damage, despite the absence of coronary arterial abnormalities. The patients who received 400 mg x kg(-1) x day(-1) of intravenous immunoglobulin (IVIG) for 5 days had a significantly lower incidence of PET abnormalities than those who received a single dose of 2000 mg x kg(-1) IVIG (P < 0.05).

Child↗
PubMed2000

Comparison of the one-and-a-half-year results of closure of patent ductus arteriosus by transcatheter coils placement with surgical ligation.

Patent ductus arteriosus (PDA) is a common type of congenital cardiovascular lesion. It usually needs surgical ligation in a full-term baby after 1 year of age. Transcatheter implantation of coils was introduced for the closure of small- to moderate-sized PDA in 1992. From November 1995 to November 1998, the authors closed the PDA in 153 patients by transcatheter implantation of coils and by surgical ligation in 10 patients. One hundred fourteen of them were studied for more than 1(1/2) years. The regular follow-up studies, including physical examination; electrocardiography; and pulsed, continuous-wave, and color Doppler flow mapping, were performed on day one and day 2, and 1 week, 1 month, 3 months, 6 months, and 1 year after the procedure. The results of the closure of PDA by surgical ligation or coil placement were compared and analyzed in all the patients.

Adolescent↗
PubMed2000

Transcatheter closure of atrial septal defect with a CardioSEAL device.

Transcatheter closure of an interatrial septal defect (ASD) with a CardioSEAL device was successfully performed on 12 Taiwanese children. There were five boys and seven girls, aged from 3.6-13.9 (8.3+/-3.2) years and with body weight of 15-57 (33.7+/-14.7) kgs. After one year of follow-up studies, which included physical examination, ECG, chest X-ray and echocardiography, complete closure of ASD was achieved in nine (75%) patients. Two children with a trivial residual shunt were asymptomatic and without audible cardiac murmur. A girl had a small residual left to right atrial shunt by color Doppler echocardiography, but without audible cardiac murmur. There were no immediate or intermediate complications. Transcatheter implantation of the CardioSEAL device is a safe and proper treatment for children with non-complicated small to medium secundum ASD.

Adolescent↗
PubMed2000

Influence of ventricular septal defect type on surgical results in children with tetralogy of Fallot.

BACKGROUND: Tetralogy of Fallot (TOF) with subpulmonary ventricular septal defects (VSD) is relatively more common among Orientals than among Occidentals. This study assessed the influence of type of VSD on surgical results in children with TOF. METHODS: Fifty-one patients with TOF (age range, 14 months to 11 years, mean 40.7 months, median 30 months, 29 boys, 22 girls) who underwent total correction by a single surgeon between January 1992 and December 1995 were retrospectively studied. Of the 51 patients, 17 patients with subpulmonary VSD were classified as group I. The remaining 34 patients with perimembranous VSD were classified as group II. All patients underwent a combined transatrial and transpulmonary surgical approach. Early postoperative results were evaluated 7 to 10 days after surgery and late postoperative results were evaluated 1 year after surgery. RESULTS: There were no statistically significant differences between the two groups in age, sex, body weight, pulmonary to systemic flow ratio, pulmonary to aortic annulus diameter ratio or preceding palliative shunt or balloon pulmonary valvuloplasty. Nevertheless, group I patients had better oxygen saturation preoperatively (84.2 +/- 4.4% vs 80.3 +/- 7.6%, p = 0.037). During surgery, the transannular patch rate was higher in group I (100% vs 73.5%, p = 0.003). The cardiopulmonary bypass time, postoperative stay in the intensive care unit, duration of chest tube placement, early postoperative residual VSD rate, and early and late postoperative residual pulmonary stenosis rate were not significantly different between the groups. However, late postoperative residual VSD rate was 33.3% in group I and 6.45% in group II, which was statistically significant (p = 0.029). There were no significant differences in arrhythmia between the two groups. CONCLUSIONS: Patients with TOF with subpulmonary VSD had a better preoperative oxygenation, higher transannular patch rate during surgery and a higher incidence of late residual VSD than those with TOF with perimembranous VSD.

Cardiac Surgical Procedures↗
PubMed1999

Prevalence and parental origin in Tetralogy of Fallot associated with chromosome 22q11 microdeletion.

OBJECTIVE: Tetralogy of Fallot is a common cardiac anomaly that is associated with chromosome 22q11 microdeletion. In this study we examined the mode of transmission as well as the parental origin of microdeletion in patients with tetralogy of Fallot. METHODS: Eighty-four children with sporadic tetralogy of Fallot (40 boys and 44 girls; mean age, 34 months) were analyzed for microdeletion at chromosome 22q11 by genotype analysis, using five microsatellite markers, D22S427, D22S941, D22S944, D22S264 and D22S311, and confirmed by quantitative polymerase chain reaction, using TUPLE1 and D22S264. All parents of these subjects consented to their own participation and their child's participation in the clinical evaluation and molecular study. To provide a molecular characterization of microdeletion, we isolated DNA from the parents and typed their DNA with each of the five polymorphic markers. RESULTS: Sixty-six patients were associated with pulmonary stenosis; and 8 of these cases (12%) had microdeletion. Eighteen patients were associated with pulmonary atresia, and 6 (33%) of these cases had microdeletion. The parental origins of the 14 patients with microdeletion were paternal in 3 cases and maternal in 11 cases. The most common mode of transmission was de novo without parental hemizygosity (93%). Transmission by autosomal dominant heredity was uncommon (7%). CONCLUSIONS: Biased parental origin was consistently found in tetralogy of Fallot patients with chromosomal 22q11 microdeletion. Our results indicated a higher prevalence of microdeletion because of inheritance of maternal microdeletion (78%).

Abnormalities, Multiple↗
PubMed1999

Treatment of pulmonary atresia with intact ventricular septum in early infancy.

BACKGROUND: Early treatment for the neonate with pulmonary atresia and intact ventricular septum (PA-IVS) is important if a high mortality rate is to be avoided. The treatment includes prostaglandin administration, balloon atrial septostomy, pulmonary valvotomy, a shunting procedure and patch repair for the right ventricular outflow tract (RVOT). This study discusses the early treatment and risk factors of this disease that are essential for assessing the risk of surgery and predicting outcome. METHODS: The medical records, echocardiograms, catheterization data and cineangiograms of 29 patients with PA-IVS diagnosed at our institution from 1987 to 1997 were reviewed retrospectively. Clinical manifestations including age, body weight, sex ratio, type of surgery and outcome were analyzed. RESULTS: Three of four patients with a right ventricular volume of less than 1 ml died, and all patients with a right ventricular volume of greater than 2 ml survived. Four of six patients with a tricuspid valvular area of between 0.25 and 0.5 cm2 died, but patients with an area of greater than 0.5 cm2 survived. One case with a monopartite right ventricle died. Patients with a bipartite or tripartite right ventricle had higher survival rates than those with a monopartite right ventricle. Patients with a the right ventricle dependent coronary sinusoid had a higher risk for mortality, even after surgery, than those with normal coronary circulation. CONCLUSIONS: A small right ventricular volume, the presence of a coronary sinusoid involving the right ventricle, a short linear length of the tricuspid valve and a small area of the tricuspid valve were the risk factors associated with a negative outcome in neonates with PA-IVS.

Female↗
PubMed1999

Percutaneous transluminal coronary angioplasty for renovascular hypertension in a child: a case report.

Since its introduction, percutaneous transluminal coronary angioplasty has become an alternative therapeutic modality to surgical and medical treatment for renovascular hypertension. We report the case of a nine-year-old boy who had hypertension caused by renal arterial stenosis. The patient's high blood pressure was 164/100 mmHg, which was discovered incidentally during a physical check-up. A selective renal angiography showed a severe short-segment stenosis with post-stenotic dilatation of the left renal artery. A 4-mm balloon catheter was advanced through the stenotic area and was inflated five times to dilate the stenosis. After the procedure, the selective renal angiography showed a significant increase in the diameter of the left renal artery. Blood pressure decreased to normal immediately after the procedure. During the one-year follow-up period, the patient remained normotensive without the use of antihypertensive drugs.

Angioplasty, Balloon, Coronary↗
PubMed1998

Metabolic detriment in donor heart valves induced by ischemia and cryopreservation.

BACKGROUND: The injury resulting from postmortem ischemia is a critical deterrent to the availability of donor valves. Using the reduction of XTT-tetrazolium salt as a marker of metabolic sequelae, we assessed the injurious effect of ischemia and the metabolic sequelae in 156 porcine semilunar leaflets. METHODS: The leaflets were randomly allocated to noncryoprocessed (n = 72) or cryoprocessed (n = 72) groups. At each preservation temperature of 4 degrees C, 24 degrees C, or 37 degrees C, 24 leaflets each were exposed to one of four storage periods of 9, 17, 30, or 60 hours. Twelve fresh aortic leaflets served as baseline reference samples. RESULTS: There was a progressive loss in the metabolic functioning of valve leaflet cells in both noncryopreserved and cryopreserved tissue as the storage times increased. Cryopreserved tissue showed a greater loss of function than noncryopreserved tissue did. The metabolic injury was mainly a consequence of cryoprocessing. The greatest loss in metabolic functioning occurred in the valves stored for 60 hours. The least favorable combination of variables was cryopreservation and a precryopreservation storage time of 60 hours. CONCLUSIONS: We conclude that 30- to 60-hour delays do not have a significant metabolic effect on cardiac leaflets. Thus it may be possible to safely extend the permissible ischemic periods after organ harvest.

Animals↗
PubMed1998

Heparinization on pericardial substitutes can reduce adhesion and epicardial inflammation in the dog.

OBJECTIVE: Primary concerns about currently available pericardial substitutes include adhesion and epicardial reaction. The purpose of this study is to evaluate host reaction to pericardial substitutes with and without incorporating slow heparin release. METHODS: To avoid biologic variation among these pericardial patches, we made a composite of six membranes. The composite membrane consisted of epoxy-fixed patches with (1) or without (2) ionically bound heparin, a glutaraldehyde-fixed patch with (3) or without (4) ionically bound heparin, an expanded polytetrafluoroethylene patch (5), and a polyester polymeric patch (6). Ten recipient dogs weighing from 12 to 19 kg (mean 13.6 kg) were used to assess the composite membranes as pericardial substitutes. The implanted composite membranes were retrieved 1 week (one dog), 2 weeks (one dog), 4 weeks (one dog), 8 weeks (one dog), and 12 weeks (six dogs) after implantation. RESULTS: Overall, the synthetic patches had a more notable inflammatory reaction than the biologic patches with or without ionically bound heparin. The heparin-bound patches caused significantly less inflammation than their nonheparinized counterparts. The heparinized porcine patches cross-linked with different compounds were found to have less fibrous formation than the nonheparinized patches and the synthetic patches. CONCLUSIONS: Heparinized pericardial substitutes may cause less adhesion and inflammatory reaction than nonheparinized material.

Animals↗