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Biomedical subjects

B Hwang

Publications and source records attributed to B Hwang.

At least 19 recordsLinked to original sources
PubMed2006

Optimizing a canine survival model of orthotopic lung transplantation.

INTRODUCTION: While acute models of orthotopic lung transplantation have been described in dogs, the technical considerations of developing a survival model in this species have not been elaborated. Herein, we describe optimization of a canine survival model of orthotopic lung transplantation. METHODS: Protocols of orthotopic left lung transplantation and single lung ventilation were established in acute experiments (n=9). Four dogs, serving as controls, received autologous, orthotopic lung transplants. Allogeneic transplants were performed in 16 DLA-identical and 16 DLA-mismatched unrelated recipient dogs. Selective right lung ventilation was utilized in all animals. A Malecot tube was left in the pleural space connected to a Heimlich valve for up to 24 hours. To date, animals have been followed up to 24 months by chest radiography, pulmonary function tests, bronchoscopy with lavage, and open biopsies. RESULTS: Long-term survival was achieved in 34/36 animals. Two recipients died intraoperatively secondary to cardiac arrest. All animals were extubated on the operating table, and in all cases the chest tube was removed within 24 hours. Major complications included thrombosis of the pulmonary artery and subcritical stenosis of bronchial anastamosis. One recipient underwent successful treatment of a small bowel intussusception. CONCLUSIONS: We report our experience in developing a survival canine model of orthotopic single lung transplantation. While short-term survival following canine lung transplantation is achievable, we report particular considerations that facilitate animal comfort, early extubation, and lung reexpansion in the immediate postoperative period, further optimizing use of this species for experimental modeling of long-term complications after lung transplantation.

Animals↗
PubMed2005

Contribution of genetic factors to neonatal transient hypothyroidism.

BACKGROUND: The causes of neonatal transient hypothyroidism (NTH) remain incompletely understood. Whether it is influenced by genetic background is rarely discussed and remains unproven. A defect in thyroid peroxidase is a common cause of dyshormonogenesis of the thyroid gland in Taiwanese, with a novel mutation (2268insT) present in nearly 90% of alleles studied. OBJECTIVE: To determine if the presence of this common mutation is associated with NTH in Taiwan. METHODS: A mismatched primer was designed and used for this specific 2268insT mutation to screen 1000 normal babies and 260 babies with confirmed NTH. RESULTS: The carrier rate for 2268insT in normal babies (1/200) was significantly lower than in babies with NTH (1/13; p<0.0001). CONCLUSIONS: The results strongly suggest that the presence of this thyroid peroxidase mutation contributes to the development of NTH. Likely pathogenetic explanations include the effect of the stress of extrauterine adaptation during labour on an immature pituitary-thyroid axis in genetically predisposed individuals, combined with environmental triggers such as iodine deficiency, perinatal iodine exposure, and/or goitrogen contamination.

Asian People↗
PubMed2004

Stimulation of asiaticoside accumulation in the whole plant cultures of Centella asiatica (L.) urban by elicitors.

The effects of a number of different elicitors on asiaticoside production in whole plant cultures of Centella asiatica were studied, including yeast extract, CdCl(2), CuCl(2) and methyl jasmonate (MJ). Only MJ and yeast extract stimulated asiaticoside production--1.53 and 1.41-fold, respectively. Maximum asiaticoside production was achieved following treatment with 0.1 mM MJ (116.8 mg/l). The highest asiaticoside production (342.72 mg/l) was obtained after 36 days of elicitation in cultures treated with 0.1 mM MJ and 0.025 mg/l 1-phenyl-3-(1,2,3-thidiazol-5-yl)urea (TDZ). Interestingly, MJ not only stimulated the production of asiaticoside but also had an important role in the senescence of C. asiatica. Although asiaticoside content did not change when TDZ was added to medium containing an elicitor, TDZ did increase shoot growth of C. asiatica. We discuss the interactive roles of MJ and TDZ in secondary metabolic production and biomass in whole plants of C. asiatica.

Acetates↗
PubMed2004

Separation of benzene, toluene, ethylbenzene, and xylenes by micellar electrokinetic capillary chromatography.

The use of sodium dodecyl sulfate, urea, beta-cyclodextrin, and methanol as additives to the electrophoretic medium containing a Na2HPO4-boric acid buffer in the micellar electrokinetic capillary chromatography of benzene, toluene, ethylbenzene, and three isomers of xylene (collectively known as BTEX) was investigated. The results showed that with the addition of sodium dodecyl sulfate only, higher selectivity and sensitivity and shorter migration time could be achieved, which consequently resulted in better separation of BTEX studied. For this buffer system, good linearity (R2>0.99) was found over the range of 5 to 500 microg ml(-1) for individual BTEX compound and separation time of less than 5 min for BTEX was possible.

Benzene↗
PubMed2004

Cardiac complications of enterovirus rhombencephalitis.

BACKGROUND: Epidemics of enterovirus 71 infection have caused the death of many children throughout the world. Rhombencephalitis, brain stem encephalitis, and heart failure were present in all of the fatal cases. However, no evidence of myocarditis was noted in the heart specimens, and the mechanism of heart failure remains unknown. AIMS: To characterise the presentation of cardiac complications in children with enterovirus rhombencephalitis and discuss its pathogenesis. METHODS: Ninety one consecutive patients with enterovirus rhombencephalitis underwent echocardiography. Of these, 17 patients (nine male, eight female; median age 14 months, range 4-57 months) with left ventricular dysfunction were studied. RESULTS: Tachycardia was noted in all patients and systemic hypertension in 12. Muscle-brain fraction of creatine kinase was >5% in 14 patients. Plasma norepinephrine and epinephrine levels were significantly raised in the three patients in whom these were analysed. Electrocardiographic abnormalities were noted in eight patients. Pulmonary oedema was complicated in 15 patients. The initial ejection fraction of the left ventricle was 22-58% (mean 37%, SD 11%). All patients deteriorated to hypotensive shock within 12 hours and 13 died. Heart specimens from seven patients showed no evidence of myocarditis, but significant coagulative myocytolysis, myofibrillar degeneration, and cardiomyocyte apoptosis were observed. CONCLUSIONS: Acute heart failure was noted in 19% of patients with enterovirus rhombencephalitis, which had a fatality rate of 77%. It was not caused by myocarditis but possibly by neurogenic cardiac damage.

Blood Pressure↗
PubMed2004

Contributions of bone maturation measurements to the differential diagnosis of neonatal transient hypothyroidism versus dyshormonogenetic congenital hypothyroidism.

AIM: To a) evaluate the contribution of bone maturation in the diagnosis of neonatal transient hypothyroidism versus dyshormonogenetic congenital hypothyroidism in full-term newborns, and b) use bone maturation to test the hypothesis that neonatal transient hypothyroidism is perinatal in onset. MATERIALS AND METHODS: The study included 20 patients with dyshormonogenetic and 43 with transient hypothyroidism. Thyroid function and measurements of the distal femoral epiphysis area, obtained at the time of first confirmatory diagnosis, were compared between the two groups. The epiphysis area in two control groups with normal thyroid function was also measured and compared with that in patients with transient hypothyroidism, at age 1-3 d (control A), or at the age when normal thyroid function was confirmed (control B). RESULTS: Mean epiphysis area was 0.04 cm2 in patients with dyshormonogenetic versus 0.22 cm2 in patients with transient hypothyroidism (p < 0.0001). An area <0.05 cm2 was limited to patients with dyshormonogenetic hypothyroidism. Conversely, a normal area (>0.2 cm2) was only observed in patients with transient hypothyroidism. Mean epiphysis areas in control A (0.20 cm2) and in patients with transient hypothyroidism were similar (p = 0.37), consistent with perinatal onset of transient hypothyroidism. Mean epiphysis area in control B (0.31 cm2) was significantly greater than in patients with transient hypothyroidism (p < 0.01). CONCLUSIONS: A short duration of hypothyroidism can significantly delay bone maturation. Examination of bone maturation at initial confirmatory evaluation yields important information pertaining to congenital hypothyroidism, not only to predict intellectual development, but also to evaluate the risk of dyshormonogenetic hypothyroidism.

Bone Development↗
PubMed2003

Poor agreement between dipyridamole-stress technetium-99m-tetrofosmin myocardial perfusion single photon emission computed tomography and two-dimensional echocardiography in Kawasaki disease.

To establish a noninvasive diagnostic method for early assessment of cardiac involvement in Kawasaki disease (KD), 28 children with KD were included in this study. Two-dimensional echocardiography (2D-Echo) to detect the aneurysms of coronary arteries (CA), as well as rest and dipyridamole-stress technetium-99m tetrofosmin (Tc-TF) myocardial perfusion single photon emission computed tomography (SPECT) to detect abnormal myocardial perfusion were performed in all of the 28 children with KD and to compare each other. The results showed that (1). 42.9% of cases had no aneurysm and 57.1% had significant aneurysms detected by 2D-Echo; (2). 42.9% of cases had normal perfusion and 57.1% of cases had abnormal myocardial perfusion assessed by Tc-TF myocardial perfusion SPECT; (3). 25.0% of cases showed both normal 2D-Echo and Tc-TF myocardial perfusion SPECT findings and 39.3% of cases showed both abnormal 2D-Echo and Tc-TF myocardial perfusion SPECT findings; and (4). there was poor agreement between 2D-Echo and Tc-TF myocardial perfusion SPECT findings (P>0.05). We concluded that poor agreement exists between aneurysms and abnormal myocardial perfusion detected by 2D-Echo and Tc-TF myocardial perfusion SPECT findings in patients with KD.

Adolescent↗
PubMed2002

Nonmyeloablative allogeneic bone marrow transplantation for orbital granulocytic sarcoma associated with t(8;21)(q22;q22) in acute myeloid leukemia.

We report a nonmyeloablative allogeneic bone marrow transplant (allo-BMT) from an HLA-matched unrelated donor in a case of acute myeloid leukemia (AML), M2 with t(8;21)(q22;q22) and the presence of orbital granulocytic sarcoma (GS), who had residual tumor after conventional chemotherapy. The course of BMT was well tolerated, with no major procedure-related toxicity. The residual orbital GS regressed completely 4 months after BMT. She is currently 19 months post BMT, disease-free. To our knowledge, this is the first reported pediatric patient with AML, GS and t(8;21)(q22;q22) who received a nonmyeloablative allo-BMT.

Acute Disease↗
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

Families of Chinese children with malignancy: the factors impact on mother's anxiety.

This study examines the impact of the stress experienced by mothers during a child's cancer treatment. A descriptive correlation study has been designed to examine the relationships between uncertainty, sense of mastery, boundary ambiguity, and anxiety. The sample consists of 100 mothers recruited in two teaching hospitals in Taiwan. The sense of mastery was found to act as a mediator between uncertainty and anxiety, whereas uncertainty was a good predictor of boundary ambiguity. The first 2 months of treatment and the incidence of cancer recurrence represented a significant special experience for mothers. Nursing intervention to improve the mothers' sense of mastery and to assist families in establishing functional patterns of parent-child interaction is discussed.

Adaptation, Psychological↗
PubMed2001

Effect of mycelial culture broth of Ganoderma lucidum on the growth characteristics of human cell lines.

Two types of purified samples, water-soluble (sample A; M. W, 1.2 x 10(6) dalton) and water-insoluble (sample C; M. W., 1.0 x 10(6) dalton) samples, were obtained through consecutive separation processes from the culture broth of Ganoderma lucidia mycelium. It was found that both samples from the culture broth were very effective in inhibiting the growth of several human cancer cell lines, having a 93-85% growth inhibition on Hep3B, AGS and A549 with the least cytotoxicity on the normal human lung cell line, WRL68 of less than 25% the highest supplementation concentration of 1.0 mg/l. In general, the sample C showed greater inhibition of cancer cell growth than the sample A. The same trend was also observed in antimutagenicity using the Chinese hamster ovary cell line (CHO test) or Salmonella typhimurium (Ames test). The CHO test showed that sample C had higher antimutagenicity on mutagens 4NQO or MMNG than sample A (approximately 40% vs approximately 25%). The percentage of antimutagenicity from the Ames test was lower than that from the CHO test, possibly due to the difference in the sensitivity of mutagens. The water-insoluble sample greatly enhanced the growth of the human T cell line (H9) up to 1 x 10(5) with sample supplementation at 1.0 mg/l concentration from 4.3 x 10(4) without sample supplementation as well as improved the secretion level of both IL-6 and TNF-alpha up to 100 pg/ml from approximately 40 pg/ml without sample supplementation. The kinetics of response to the immune cell growth was illustrated by the response time obtained when the sample concentration was increased. The water-insoluble sample can be used for effectively treating cancer in that it accelerated apoptosis of human carcinoma cells up to 70% compared to less than 50% for the control. The sample also increased the differentiation ratio of HL-60 cells up to 58% after four days of cultivation, compared to 18% in the case of no sample supplementation. These results can be used in implying that the insoluble part of G. lucidium mycelium culture broth must be related to controlling signal transduction, resulting in the regulation of cancer cell growth.

Journal Article↗
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↗
PubMed2000

The effects of social interactive training on early social communicative skills of children with autism.

Growing attention has been directed at the relation between early social communicative skills of children with autism and subsequent development of these children's social and communicative functioning. We reviewed 16 empirical studies that investigated the effects of social interactive interventions designed to increase early social communicative skills of young children with autism by increasing their role as initiator of social interactions. To identify factors relating to treatment effectiveness, we analyzed studies in relation to participant characteristics, settings, target behaviors, training methods, and results. To determine durability of treatment, we analyzed generalization effects across persons, settings, stimuli, and time. Increases were found for social and affective behaviors, nonverbal and verbal communication, eye contact, joint attention, and imitative play. Limited generalization or maintenance of target behaviors was reported. Findings are discussed in relation to critical variables that may relate to treatment effectiveness in future research and practice efforts.

Autistic Disorder↗
PubMed2000

Comparison of 201Tl SPET and treadmill exercise testing in patients with Kawasaki disease.

About 4% of children with Kawasaki disease ultimately develop ischaemic heart disease. Therefore, the early detection, non-invasive monitoring and long-term follow-up of myocardial ischaemia are essential. We compared the sensitivity and specificity of 201Tl single photon emission tomography (SPET) and treadmill exercise in the detection of myocardial ischaemia in 23 patients (19 boys, 4 girls) with Kawasaki disease. They were divided into two groups according to the results of coronary angiography. Group I consisted of 11 patients with coronary abnormalities; Group II consisted of 12 patients with no coronary abnormalities. The sensitivity, specificity, false-positive and false-negative rates for detecting coronary arterial lesions were 72.7% (8/11), 58.3% (7/12), 38.5% (5/13) and 30% (3/10) for 201Tl SPET, and 45.5% (5/11), 100% (12/12), 0% (0/5) and 33.3% (6/18) for treadmill exercise, respectively. We conclude that 201Tl SPET is more sensitive than treadmill exercise for the detection of coronary arterial abnormalities, but that the specificity of treadmill exercise is better than that of 201Tl scintigraphy. Coronary artery lesions detected by coronary angiography have good concordance of ischaemic areas with perfusion defects detected by 201Tl SPET. When ischaemic findings on 201Tl SPET and/or positive treadmill exercise testing are noted, coronary angiography is strongly indicated to detect possible stenotic lesions in the coronary arteries.

Adolescent↗
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

Pseudoaneurysm formation after infected modified Blalock-Taussig shunt: echocardiographic findings.

The modified Blalock-Taussig (B-T) shunt is well recognized as a palliative procedure for cyanotic congenital heart disease in infants. Pseudoaneurysm formation after a modified B-T shunt is a rare complication. We present the case of a 9-month-old girl with tetralogy of Fallot who had undergone a modified left B-T shunt at 5 months of age and developed a pseudoaneurysm after an episode of infective endocarditis as detected by echocardiography. Compression of the left bronchus, displacement of the mediastinum to right chest, and paralysis of the left hemidiaphragm were found. Magnetic resonance images, computed tomography scans, aortograms, and selective angiograms demonstrated the presence of a large pseudoaneurysm. The compression syndrome gradually disappeared after aneurysmectomy.

Anastomosis, Surgical↗
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↗