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Biomedical subjects

B Hwang

Publications and source records attributed to B Hwang.

At least 73 records · Page 4Linked to original sources
PubMed1995

Characterization of a postjunctional 5-HT receptor mediating relaxation of guinea-pig isolated ileum.

The 5-HT receptor mediating postjunctional relaxation of precontracted guinea-pig ileum has been characterized using several agonists and antagonists. Substance P precontracted tissues were potently relaxed by 5-HT (5-hydroxytryptamine, serotonin), 5-CT (5-carboxamidotryptamine) and several other indoles. The rank order of potency, with pEC50 values in parentheses, was 5-CT (7.6) > 5-methoxytryptamine (5.7) > 5-HT (5.5) > alpha-methyl-5-HT (4.7) > 2-methyl-5-HT (< 4.0) = tryptamine (< 4.0) = N,N-dimethyl-tryptamine (< 4.0) = N,N-dimethyl-5-HT (< 4.0) = dipropyl-5-CT (< 4.0) = sumatriptan (< 4.0). 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)-tetralin) acted as a potent (6.3), but partial, agonist with respect to 5-HT. The responses to 5-CT were antagonized by several compounds with the following rank order of affinity, with pKB values in parentheses: LSD (lysergic acid diethylamide; 8.1) = mesulergine (7.8) > methysergide (7.6) = spiperone (7.6) > clozapine (7.3) >> (-)-pindolol (< 6.0) > ketanserin (< 6.0) = ondansetron (< 6.0) = GR 113808 ([1-(2-methane-sulphonamido-ethyl)-piperidin-4-yl]-methyl-in dole-3- carboxylate maleate; < 6.0). The relaxant responses to 5-HT were also resistant to tetrodotoxin. These data are consistent with a functional 5-HT receptor, mediating relaxation of guinea-pig ileum, which exhibits an operational profile similar to that of the cloned guinea-pig 5-ht7 receptor. This study, therefore, provides evidence for a functional correlate of the 5-ht7 gene product.

5-Methoxytryptamine↗
PubMed1995

Combination chemotherapy with vinblastine, bleomycin, cisplatin, and etoposide (VBPE) in children with primary intracranial germ cell tumors.

We have treated 13 children with primary intracranial germ cell tumors with the combination of vinblastine, bleomycin, cisplatin, and etoposide, the so-called VBPE regimen in the past seven years at one institution. The clinical diagnosis of these children were: three germinomas, seven non-germinomatous germ cell tumors, and three recurrent non-germinomatous germ cell tumors without previous chemotherapy. Of this group, three germinomas and three non-germinomatous germ cell tumors were treated primarily with VBPE plus radiotherapy. All of them responded completely, and were free of tumor. Primary VBPE regimen without radiotherapy was used in another four non-germinomatous germ cell tumors. After six courses of VBPE regimen, only one of the four patients achieved complete response for 30 months. VBPE regimen was used as salvage chemotherapy in three recurrent non-germinomatous germ cell tumors without previous chemotherapy. After six courses of VBPE regimen, two had complete response for 58+ months and 78+ months respectively. We concluded that in newly-diagnosed intracranial non-germinomatous germ cell tumors, the combination of chemotherapy VBPE regimen and radiotherapy led to good results. Primary chemotherapy with VBPE alone was not adequate for the treatment of non-germinomatous germ cell tumors. However, VBPE regimen might be one of the salvage therapies for recurrent germ cell tumors without chemotherapy before relapse.

Adolescent↗
PubMed1995

The evaluation of percutaneous central venous catheters--a convenient technique in pediatric patients.

OBJECTIVE: To evaluate the feasibility and effectiveness of 3 different types of silastic catheters that were used for percutaneous central venous catheterization (PCVC) through peripheral veins. DESIGN AND SETTING: The study was prospective and consecutive for 6 years at a pediatric/neonatal intensive care unit and pediatric ward in Veterans General Hospital-Taipei, a university-affiliated medical center, in Taiwan, ROC. PARTICIPANTS AND INTERVENTIONS: The patients who had PCVC were consecutively enrolled from January 1988 to December 1993. Three types of silastic catheters were used. The classification was according to the caliber as small catheter (SC, 0.30 mm ID), mid-size catheter (MC, 0.51 mm ID) and large catheter (LC, 0.64 mm ID). The same insertion technique, catheter-through-needle, was used for all PCVC placements through the peripheral vein. After insertion, each catheter was connected to a conventional short cannula (24-, 22-, or 20-gauge) of compatible caliber, and then linked to the infusion system. RESULTS: 1318 PCVCs were used in 1126 consecutive patients, that included 754 SCs in 649 infants (among them 60.9% were less than 1500 g), 383 MCs in 319 toddlers, and 181 LCs in 158 children. Mean (SD) body weight at the time of catheter insertion was SC 1.7(0.9)kg, MC 12.1(6.5)kg and LC 19.3(7.6)kg. Overall, mean (SD) duration of these PCVC was 16.4(8.4) days. A significantly longer duration was noted in: (a) SC group with 19.7(10.4) days than the other two groups [MC 12.4(6.5) days, LC 11.2(5.0) days]; (b) patients with body weight equal to or less than 3.0 kg [18.7(8.6) versus 14.1(6.1); and (c) insertion sites other than external jugular vein (EJV) [18.8(9.7) versus 11.7(6.0)]. These PCVCs provided reliable venous access for multiple purposes such as hyperalimentation, venous access or sampling of blood, antibiotic therapy and chemotherapy. MC and LC were also used for monitoring the central venous pressure. Most of the time, SC and MC were inserted through the superficial peripheral vein of the scalp, neck and extremities, while LC was almost approached via the EJV. The overall success rate of insertion was 92.4% (1318/1427). No significant difference was observed among the different catheter groups [93.4% (754/807) in SC, 90.5% (383/423) in MC and 91.9% (181/197) in LC] and the different insertion sites. Within each group of PCVC, more than eighty percent of catheters were removed electively: 83.3% in SC, 89.6% in MC and 84.5% in LC. Probable catheter-related sepsis accounted for 2.7% (36/1, 318) of all PCVCs. With this study, the cost of each PCVC set is 3.0 US dollar. CONCLUSION: This study indicates that the use of three different calibers of silastic catheter is feasible and effective for PCVC in pediatric practice.

Body Weight↗
PubMed1995

A quality study of a computerized medical birth registry.

Processed by a computerized medical birth registry system, the birth records of 20,103 deliveries, from February 1992 to February 1993, were digitized with medium registry. From January 1, to February 28, 1993, the original records (n = 2,840 cases) of all 10 collaborative hospitals were requested for assessment of the data quality. Thirty-six items were scored, data of poor quality was found in 8 items; acceptable quality in 4 items; and good quality in 28 items. The feasibility of data transfer by floppy disc and per modem was evaluated. This registry system had shortened data processing time effectively and improved mutual feedback between data center and delivery units. Errors resulting from technical faults originating in preparation of the data for computerizing at hospital level could be effectively reduced. The validity of diagnosis remained as the major source of errors.

Birth Certificates↗
PubMed1995

A quantitative analysis of the structure of right ventricle-pulmonary artery junction for balloon pulmonary valvuloplasty in children.

Percutaneous balloon valvuloplasty (PBVP) was performed in 55 children, aged from four days to twelve years and nine months, with different severity of congenital pulmonary stenosis (PS). To evaluate its efficacy, a quantitative analysis of the structure of right ventricle-pulmonary artery junction was conducted. Significant reductions of peak systolic right ventricular pressure, ratio of peak right-to-left ventricular pressure, and pressure gradients between the right ventricle and pulmonary artery were obtained in 48 children who scored 3 or less (Group I) and 7 children who scored over 3 (Group II) (P < 0.05). After two to forty-six months (M +/- SD = 17.1 +/- 15.5 months) of follow-up study, the residual gradients between right ventricle and pulmonary artery over 36 mmHg were higher in children who scored over 3 than in those who scored 3 or less (71.4% vs 20.8%) (P < 0.01). Repeated percutaneous balloon valvuloplasty was successfully performed in 4 children, 2 each in Group I and Group II. Surgical open pulmonary valvotomy was needed in 1 in Group II because of the dysplastic pulmonary valve and the need for repair of atrial septal defect and in 2 in Group I because of the failure to complete repeated PBVP in the catheterization laboratory or the need for repair of associated atrial septal defect.

Blood Pressure↗
PubMed1995

Percutaneous balloon valvuloplasty in severe pulmonary valvular stenosis.

Percutaneous balloon pulmonary valvuloplasty (PBPV) was achieved successfully in 20 of 22 patients with severe pulmonary valvular stenosis, aged two days to ten years (median four years and two months). The diameters of the balloon for PBPV were 88-125% (mean +/- SD = 109.5 +/- 10.0%) of the pulmonary valve annulus. PBPV failed in 2 patients because of the inability of the cardiac catheters to cross the stenotic valve. A significant reduction of right ventricle-pulmonary artery (RV-PA) pressure gradient occurred in all 20 patients (mean +/- SD = 72.1 +/- 10.3%). The mean RV-PA pressure gradient was reduced from 93.2 +/- 33.1 to 26.3 +/- 15.6 mmHg (P < 0.0001) and the mean right ventricular peak systolic pressure fell from 117.2 +/- 32.4 to 51.6 +/- 17.3 mmHg (P < 0.0001). Five (25%) of 20 patients had an infundibular gradient before PBPV. Two (10%) developed a new infundibular stenosis immediately after PBPV. Four (20%) presented with cyanosis, which disappeared after the successful PBPV. Two patients (10%) who showed a residual RV-PA pressure gradient of more than 40 mmHg had a significant infundibular obstruction initially. Two patients underwent recatheterization fifteen months after PBPV owing to a significant residual RV-PA pressure gradient and had no reductions in right ventricular pressure and RV-PA pressure gradient, but resolution of infundibular obstruction was noted in both. Repeat PBPV was successfully performed on these 2 patients. No significant complications were noted in any patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1995

Palliative treatment for tetralogy of Fallot with percutaneous balloon dilatation of right ventricular outflow tract.

Percutaneous balloon pulmonary dilatation of the right ventricular tract was performed on 16 children with tetralogy of Fallot for palliative purposes after routine cardiac catheterization. Immediate improvement in aortic saturation from 73.4 +/- 6.8 to 84.0 +/- 4.8% (mean +/- SD = 10.6 +/- 2.7%, p < 0.001) and clinical symptoms were achieved in all 16 cases. The pressures in the right ventricle, pulmonary artery, left ventricle and aorta showed no remarkable changes after percutaneous balloon dilatation. The diameters of the proximal end and at the first branching of the right and left pulmonary arteries, pulmonary arterial index and the diameter of the descending aorta at the diaphragm increased significantly after balloon dilatation (p value 0.0004-0.006). One child suffered from repeated cyanotic spells in spite of the immediate improvement of aortic saturation. She received a left side Blalock-Taussig shunt 2 months after the balloon dilatation. None of the children had a significant complication. Eight had follow-up cardiac catheterization one year later and demonstrated much improvement in the diameters of the proximal end and at the first branching of the right and left pulmonary arteries, pulmonary arterial index and the diameter of the descending aorta at the diaphragm (p value 0.005-0.04). All 8 patients had their cardiac lesions successfully corrected. Percutaneous balloon dilatation is an alternative palliative therapy for children with tetralogy of Fallot.

Cardiac Catheterization↗
PubMed1995

Quality of life in applied research: a review and analysis of empirical measures.

A consensus list of 15 dimensions and corresponding components of quality of life was derived from the literature and proposed as a conceptual model. Eighty-seven empirical studies found in the applied research then were analyzed, and the proposed model was found to be supported by 1,243 empirical measures. In addition, studies were analyzed with respect to (a) demographic variables, (b) type of investigation, (c) method of assessment, (d) psychometric properties of assessments used, and (e) common dimensions of measures investigated and their frequency of measurement. Based upon findings, issues regarding methodology, implications for policy and practice in the field, and recommendations for future research were discussed.

Humans↗
PubMed1995

The application of a modified mini-flexible-fiberoptic endoscopy in pediatric practice.

BACKGROUND: The application of bronchoscopy in infants and small children is still restricted in most institutions because of their limited airways. The purpose of this study was to evaluate the usefulness of a modified mini (2.1 mm OD) flexible fiberoptic endoscope (FFE) in diagnosis and therapy of suspected pediatric airway problems. METHODS: A prospective two-year study was carried out in a tertiary care neonatal/pediatric intensive care unit and general ward in a children medical center of a university-affiliated hospital. The employed mini-FFE (Machida ENT-30 F III, Tokyo, Japan) was modified with the addition of an external silastic catheter (0.5 mm inward diameter, 0.9 mm outward diameter) for suctioning, oxygen delivery, and medications during study. RESULTS: Totally, 247 laryngoscopies and 212 bronchoscopies were performed in 207 patients without significant morbidity or any associated mortality. The age of patients ranged from 1 day to 10 years. About one-fifth of the procedures (larngoscopy 21.5%, 53/247; bronchoscopy 19.8%, 42/212) were performed in patients under the age of one month. Patient's body weight ranged from 650 g to 40 kg. About fifty-five percent of the procedures (laryngoscopy 55.1% 136/247; bronchoscopy 55.2%, 117/212) were performed in patients weighing less than 5 kg. The most common path of either laryngoscopy (94.3%, 233/247) or bronchoscopy (94.8%, 201/212) was through the nasal route. In 102 patients who had been demonstrated to have upper airway problems, 16 patients (15.7%) also proved to ahve significant lesion(s) below the glottis. CONCLUSIONS: This modified FFE is a safe and a valuable instrument that can serve as an important aid in the diagnosis and therapy as well as a guide for surgical intervention of respiratory tract disorders in small infants and children.

Bronchoscopes↗
PubMed1995

Comparison of radioisotopic and ultrasonic scanning in the evaluation of neonatal hypothyroidism.

BACKGROUND: Technetium-99m pertechnetate (Tc-99m) scan is presently the best diagnostic modality to delineate the anatomy of the neonatal thyroid. Because several factors will inhibit Tc-99m uptake in a normal thyroid gland and the Tc-99m scan requires expensive equipment and sometimes raises fear of radiation in parents, the ultrasonography might be an important complementary method for neonatal thyroid disorders. We described our experience with ultrasonography of the thyroid in 52 infants with suspected congenital hypothyroidism to compare the results obtained by using Tc-99m imaging in the same infants. METHODS: From Dec. 1991 to May 1992, 52 neonates with suspected congenital hypothyroidism by newborn screening were referred to Veterans General Hospital-Taipei for confirmatory diagnoses. All of them were investigated with Tc-99m and ultrasonography of the thyroid gland. Results of Tc-99m scan and ultrasonography were compared and analyzed. RESULTS: The ultrasonography failed to identify any ectopic gland and all cases were misinterpreted as hypoplasia or hemiagenesis of thyroid gland, but it never misinterpreted them as normal thyroid glands. The ultrasound never misinterpreted normal thyroid gland, while the Tc-99m scan misguided a normal gland as an athyreotic gland. CONCLUSIONS: The ultrasonography may be adopted as the first line image examination for the babies with suspected congenital hypothyroidism. If sonography shows abnormal thyroid gland such as hypoplasia, hemiagenesis or agenesis, the isotopic scan may be a good complementary method to confirm the diagnosis.

Female↗
PubMed1994

Fungal infection of ventriculoperitoneal shunts in children.

Infection is still the most common complication of shunt procedures in children. However, fungal infection is still considered to be rare. We found that fungi accounted for 17% of shunt infections (8 of 48) in a retrospective study. All of the patients were premature babies and had received a ventriculoperitoneal shunt because of hydrocephalus. The clinical manifestations were subtle and insidious. The time of onset of infection ranged from 1 month to 1 year after the insertion of the shunt. Examination of the cerebrospinal fluid of infected patients showed mild pleocytosis with an elevated protein concentration. Candida species (including Candida albicans, Candida parapsilosis, and Candida tropicalis) or Torulopsis glabrata were isolated. In all but one case, shunts were removed and systemic therapy with amphotericin B was administered. Amphotericin B was given intrathecally to two patients, who did not respond to systemic therapy. Treatment with fluconazole failed for one patient. We suggest performing fungal cultures in cases of shunt infection, especially those involving premature infants. Extraventricular drainage, systemic therapy with amphotericin B, and insertion of a new shunt remain the principal components of the treatment regimen for fungal shunt infections in children.

Amphotericin B↗
PubMed1994

Analysis of subunit assembly of the Na-K-ATPase.

The Na-K-ATPase, or sodium pump, is comprised of two subunits, alpha and beta. Each subunit spans the lipid bilayer of the cell membrane. This review summarizes our efforts to determine how the two subunits interact to form the functional ion transporter. Our major approach has been to observe the potential for subunit assembly when one or both subunits are truncated or present as chimeras that retain only a limited region of the Na-K-ATPase. DNAs encoding these altered subunit forms of the avian Na-K-ATPase are expressed in mammalian cells. Monoclonal antibodies specific for the avian beta-subunit are then used to purify newly synthesized avian beta-subunits, and the presence of accompanying alpha-subunits indicates that subunit assembly has occurred. The ectodomain of the beta-subunit (approximately residues 62-304) is sufficient for assembly with the alpha-subunit, and a COOH-terminal truncation of the beta-subunit that lacks aminoacyl residues beyond 162 will assemble inefficiently. A maximum of 26 aminoacyl residues of the alpha-subunit are necessary for robust assembly with the beta-subunit, when this sequence replaces the COOH-terminal half of the loop between membrane spans 7 and 8 in the SERCA1 Ca-ATPase. This region of the Ca-ATPase faces the lumen of the endoplasmic reticulum. These findings encourage study of other related questions, including whether there is preferential assembly of certain subunit isoforms and how various P-type ATPases are targeted to their appropriate subcellular compartments.

Amino Acid Sequence↗
PubMed1994

Pancreatoblastoma: a case report.

Primary neoplasms of the pancreas are rare in children. One variant of these tumors is pancreatoblastoma, comprising 0.5% of epithelial tumors of the pancreas. It usually affects children at 1-8 years of age, with quite equal sex ratio. The tumor can be found at any site of pancreas, but it most commonly arises in the head of pancreas. Histopathologically, pancreatoblastoma is an encapsulated tumor with distinct organoid structures and sometimes squamoid corpuscles. Acinar cells with zymogen granules are occasionally found. The tumor has favorable prognosis. We present a 14-year-old female who was admitted due to prolonged jaundice for about 2 months. Physical examination revealed pale conjunctiva, yellowish skin color and hepatosplenomegaly. Abdominal sonography and CT scan showed dilated common bile duct and a tumor mass about 2 x 2 cm in dimension located a pancreatic head. She received surgical operation to relieve obstructive jaundice and later Whipple's operation for radical resection. Six months after operation, the patient received the examination of abdominal sonography, CT scan and gallium tumor scan but there was no evidence of local recurrence or distant metastasis. Now the patient is living well for more than one year. Because of its rare occurrence, we demonstrate this case and review the literature.

Adolescent↗
PubMed1994

Comparison between skin testing and in vitro testing for diagnosis of allergen in asthmatic children.

BACKGROUND: This study was designed to compare the skin testing and in vitro testing for the diagnosis of most common inhalant allergens in asthmatic children. METHODS: Sixty-two asthmatic children positive to most common allergens in the area of skin tests and multiple allergosorbent chemiluminescent assay (MAST-CLA) were subjected to another Pharmacia CAP test (CAP). RESULTS: The agreement between the results of MAST-CLA and CAP was variable. The correlation coefficient for CAP with MAST-CLA was significant for five allergens except candida, dog dander and Willow pollen when the diagnostic levels of MAST-CLA and CAP were compared with skin test reactions. For all the allergens tested, MAST-CLA showed a sensitivity of 51%, a specificity of 84% and an efficiency of 73%, compared with 57%, 80% and 74%, respectively, in the CAP analysis. CONCLUSIONS: MAST-CLA and CAP can be used as a screening test to measure allergen IgE level. Both MAST-CLA and CAP were comparable in their ability to diagnose of allergy to tested allergens.

Adolescent↗
PubMed1994

Percutaneous balloon valvuloplasty for congenital critical pulmonary stenosis in neonates.

BACKGROUND: Percutaneous balloon valvuloplasty (PBVP) was performed on 6 neonates with severe pulmonary stenosis to evaluate its efficacy. METHODS: The 6 studied neonates were aged from 1 to 30 days and weighed 2.5 to 3.3 kg. Follow-up period ranged 6-21 months with a mean of 11.5 +/- 6.3 months. RESULTS: Dramatic improvement after PBVP was obtained not only on the clinical manifestations but also on the hemodynamic data. After percutaneous balloon valvuloplasty, the aortic O2 saturation increased significantly from 71.3 +/- 14.8% to 83.2 +/- 9.3% (p = 0.001) in 5 neonates who had cyanosis before PBVP. The right to left ventricular peak systolic pressure ratio decreased significantly from 1.65 +/- 0.41 to 0.77 +/- 0.27 (p < 0.001). The peak systolic right ventricular pressure dropped significantly from 104.0 +/- 18.8 to 48.8 +/- 13.6 mmHg (p < 0.001). The peak systolic gradient between right ventricle and main pulmonary artery dropped significantly from 83.2 +/- 16.2 to 24.3 +/- 16.3 mmHg (p < 0.05). CONCLUSIONS: The percutaneous balloon valvuloplasty is safe and effective in treating the neonates with congenital critical pulmonary stenosis.

Catheterization↗
PubMed1994

The efficacy of different umbilical cord care regimens: an in vitro study on their drying and antimicrobial effect.

BACKGROUND: Topical regimens have been used for umbilical cord care for different purposes, but their drying efficacy has rarely been statistically analyzed. We designed an in vitro study with six regimens to determine which one can achieve the best drying and antimicrobial effects in umbilical cord care. METHODS: Twenty-seven umbilical cords were resected when babies were born. Each cord was cut into seven segments in appropriate length and randomly labeled to seven groups. Six regimens including 75% alcohol, 90% alcohol, tincture povidone-iodine, aqua povidone-iodine, Chinese herbs, and one powder agent (M) were used topically on six groups of umbilical cords once daily. The control group received no treatment. Daily weight of the cords was recorded for 7 days, and bacterial culture was performed on the sixth day. RESULTS: All study groups presented similar algebraic functional relationship between weight change and time. The drying effect occurred mostly within the first 3 days (weight loss 88.6%), especially on the first day (62.1%). Mean ratio of the final weight/initial weight was 10.2%. Significant day-by-day weight loss was noted from day 1 to day 5 (p < 0.001). Both aqua and tincture povidone-iodine groups showed not only satisfied drying effect but also significantly better antimicrobial effect than other groups. CONCLUSIONS: Povidone-iodine has both good drying and antimicrobial effects in umbilical cord care. As the topical use of povidone-iodine has been reported to relate to transient neonatal hypothyroidism, we suggest it to be used only as a good substitute if there are signs of umbilical cord infection.

1-Propanol↗
PubMed1994

Non-traumatic injuries in childhood: an epidemiological survey.

BACKGROUND: Accident is the major cause of morbidity and mortality in childhood. The incidence of various non-traumatic injuries has increased due to proliferation of many chemical products and curiosity of little children, which needs our special attention for prevention. METHODS: Two hundred and sixty-six children were sent to the pediatric emergency room of Veterans General Hospital-Taipei from January 1990 to December 1993 with a diagnosis of non-traumatic injuries. Retrospective analysis of their medical records was performed. RESULTS: Household materials were the most common ingested material causing non-traumatic injuries, followed by drugs, foreign bodies and gases. The male to female ratio was 1.3:1. The children were most commonly 1 to 3 years of age (66.2%), especially between 13 to 24 months. Benzodiazepines, pesticides and coins were the most common causes in drug, household material and foreign body groups, respectively. Sixty-two percent of cases had symptoms, and the major presentations occurred in central nervous system. Ninety-two percent of non-traumatic injuries happened at home, and ninety-two percent of the events were accidental. Approximately thirty percent of patients needed hospitalization. Ultimately, two cases died and another three had severe sequelae. CONCLUSIONS: Boys at 1-3 years of age had the highest proportion among young victims of non-traumatic injuries especially via accidental ingestion or poisoning, and home was the most common site of event. Proper prevention with education to the parents and children is of the most importance to eliminate such injuries.

Accidents↗