Search PubMed⌕ Search

Biomedical subjects

K W Chang

Publications and source records attributed to K W Chang.

At least 55 records · Page 3Linked to original sources
PubMed1993

External and middle ear status related to evoked otoacoustic emission in neonates.

OBJECTIVE: Screening auditory status prior to neonatal hospital discharge to identify newborns with severe hearing impairment is an important pediatric care priority. Evoked otoacoustic emission (OAE) testing is a quick noninvasive method. The purpose of this study was to determine the relationship between external auditory canal and middle ear status with click-evoked OAE. It was hypothesized that vernix caseosa, debris in the ear canal, and middle ear fluid contribute to the OAE fail rate. DESIGN: All neonates had an initial OAE examination. A second investigator, "blinded" to the results, examined all ears otoscopically, cleaned any obstructing debris, and repeated with a second OAE test. SETTING: All neonates were tested in a designated nursery at a mean age of 43 +/- 21 hours. PATIENTS: Forty-one full-term neonates were prospectively enrolled. INTERVENTION: The ear canals with debris were cleaned under direct vision with a pediatric swab dampened by an alcohol wipe. OUTCOME MEASURE: The primary outcome measure was the postcleaning OAE pass rate. RESULTS: The preotoscopic examination pass rate of 82 ears was 76%. The OAE pass rate improved to 91% after debris removal. CONCLUSIONS: The results indicate that the examination and cleaning of the external ear canal are important components of the neonatal screening process.

Acoustic Stimulation↗
PubMed1993

Mechanics of anatomic reduction of thoracolumbar burst fractures. Comparison of distraction versus distraction plus lordosis, in the anatomic reduction of the thoracolumbar burst fracture.

The adequate reduction of vertebral burst fractures is dependent on successful application of distractive forces in combination with the restoration of normal spinal lordosis. However, the optimal sequence of distraction in comparison to distraction plus lordosis in the anatomic restoration of the fractured thoracolumbar spine has not been described. Burst fractures of the L1 vertebra were first created and the reduced in vitro using three differing reduction techniques. In six fresh human cadaver spine specimens, the mean fracture severity based on the degree of canal compromise was 31% (SD +/- 20%) after fracture. Reductions were performed using the AO Fixator Intern, the Reduction Fixation (RF) Device, and the Steffee plate systems following standard clinical techniques. The AO Fixator Intern provided independent but variable control of distraction and lordosis, the RF device provided variable distraction with independent, but preset, correction of lordosis and the Steffee system provided set distraction and stabilization. Both the AO and RF devices restored the lordosis (7.6 degrees +/- 5.2 degrees and 9.7 degrees +/- 4.5 degrees, respectively) better than the Steffee plate system (0 degrees +/- 1.6 degrees). However, the AO device provided poorest restoration of the posterior vertebral body height (92% vs 96% for the RF device and 99% for the Steffee plate). The RF device, which restored both lordosis and posterior vertebral body height to the near anatomic prefracture level, provided significantly better canal clearance (9% +/- 8%) than the other techniques, P < 0.05. The study demonstrates that instrumentation systems that provide independent correction of distraction and lordosis can best restore anatomic alignment, with indirect neurodecompression of the compromised spinal canal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Carcinoma in multinodular goitre.

A retrospective review of 107 patients operated on for multinodular goitre was carried out to determine the incidence of carcinoma. Of the group 7.5 per cent harboured incidental carcinomas with papillary carcinoma being the most common variety. The indications for removal of multinodular goitre should be compressive symptoms, suspicion of malignancy and cosmesis.

Adolescent↗
PubMed1992

A reduction-fixation system for unstable thoracolumbar burst fractures.

Thirty-three patients with unstable burst fractures of the lower thoracic and lumbar spine were treated with a reduction-fixation system. The new system is used both as a reduction and a fixation device for disorders of the lower thoracic and lumbar spine. In treatment of spinal fractures, it provides symmetric lordotic distraction to obtain the best possible reduction of intracanal fragments, and rigidly stabilizes the fractured vertebra while involving the minimum number of segments. All patients had a minimum follow-up of 24 months. Most patients in this series had a near-anatomic reduction of all three columns in the involved segment. The "indirect" neurologic decompression was successful in cases treated early after injury. The fixation was rigid enough to allow early mobilization and rehabilitation in a light orthosis within 1 week after surgery, and there was minimal loss of reduction during the follow-up period. The complications were minor. The reduction-fixation system achieved the surgical goals of posterior instrumentation for treatment of unstable thoracolumbar burst fractures.

Adult↗
PubMed1992

Effect of H2 antagonists on outcome of simple closure for perforated duodenal ulcer.

The treatment of perforated duodenal ulcer is controversial. Since the advent of H2 antagonists, the number of ulcer operations has declined tremendously. We wanted to find out if the addition of a H2 antagonist after simple closure of a perforated duodenal ulcer would change the outcome and therefore reviewed 46 patients treated in this fashion. Our results show that this is a safe and effective way of treating patients with perforated duodenal ulcer.

Adolescent↗
PubMed1992

Prenatal diagnosis of intestinal obstruction due to ileal atresia.

A case of intestinal obstruction due to ileal atresia where the diagnosis was made prenatally by ultrasound is presented. Close monitoring of the fetus was done ultrasonographically to look for any evidence of meconium peritonitis. The baby was delivered preterm but weighed 3.3 kg. Laparotomy and enterostomy was done and the baby is currently well.

Female↗
PubMed1991

Persistent müllerian duct syndrome--a case report.

An eighteen month old phenotypically and genotypically normal male child was admitted with a left inguinal hernia and a right undescended testis. At operation, he was found to have a uterus, bilateral fallopian tubes, and a vagina in the left hernial sac. Bilateral orchidopexies and excision of the persistent Mullerian duct structures were carried out. This rare case of persistent Mullerian duct syndrome is due to a defect in Mullerian regression, which is in turn controlled by the Mullerian inhibiting substance (MIS). Orchidopexy with excision of the persistent Mullerian duct structures is usually not possible without damage to the vas deferens which is closely adherent to the wall of the uterus. The alternative of leaving the persistent Mullerian duct structures alone and performing a staged or primary orchidopexy has been suggested.

Disorders of Sex Development↗
PubMed1990

Characterization of two new cell lines derived from oral cavity human squamous cell carcinomas--OC1 and OC2.

Two continuous cell lines, OC1 and OC2, have been established. Each one was derived from a surgical specimen of buccal mucosa squamous carcinoma from a Chinese man. Both cell lines grew as adherent monolayers and had an epithelioid morphology. The cell lines have now been grown in vitro for more than 200 passages over a 2-year period. Both cell lines were tumorigenic in nude mice. Histologic examination of the mice tumors showed a positive identification with those from the original human squamous cell carcinoma. Electron microscopic examination convincingly demonstrated their epithelial origin. Chromosomal numbers of the OC1 cell ranged from 58 to 78 and of the OC2 cells ranged from 62 to 82. Analysis of cytokeratin showed that all cell lines were positive. The carcinoembryonic antigen (CEA) tested negative in these two cell lines. The OC2 cell line showed the presence of HPV16, but the OC1 cell line did not. These cell lines should be useful for investigation of anticancer treatment and for their possible relationship to human papilloma virus (HPV).

Carcinoma, Squamous Cell↗
PubMed1990

Continuing root formation following apexification treatment.

A case report is presented in which continuing root formation occurred in an immature mandibular second premolar after calcium hydroxide apexification treatment. An apical hard tissue barrier was accompanied by a separate disto-apically growing root 18 months posttreatment. Histologic evaluation of the root revealed immature hard tissue mixed with calcium hydroxide, connective tissue and bone, apically in the original root canal. In the separate new formed part of the root, pulp tissue, odontoblasts, predentin, cementum and an apical foreman could be identified.

Calcium Hydroxide↗
PubMed1990

[A study on the chairside dental assistants in the Republic of Korea].

It is recommended that the chair-side dental assistant should be utilized in order to increase the production of dental health care by World Health Organization. In the Republic of Korea, there was no chair-side dental assistant by legally. So the authors investigated and discussed for the development of chair-side dental assistant in Korea. Obtained results were as follows 1. In order to increase the production of dental health care chair-side dental assistants should be developed. 2. Institution of chair-side dental assistant will be established legally. 3. Trained chair-side dental assistant will be positioned in dental clinics for dentist and health centers for dental public health.

Dental Assistants↗
PubMed1989

High prevalence of human papillomavirus infection and possible association with betel quid chewing and smoking in oral epidermoid carcinomas in Taiwan.

Seventeen oral epidermoid carcinomas, three oral papillomas, and 17 normal gingival tissues were tested for the presence of human papillomavirus (HPV) types 6, 11, 16, and 18 sequences by Southern blot hybridization. Episomal HPV-16 sequences in various amounts were detected in 76.4% of the oral carcinomas and in all three cases of papilloma. However, only one of the 17 normal tissues was HPV positive with an unknown type. None of the samples contained HPV-6, -11, or -18 sequences. Examination of the habits of the patients showed that 59% of the patients were betel quid chewers and 82% were smokers. Thus, the concurrent incidence of HPV infection and betal quid chewing and/or smoking habits in oral carcinoma patients observed in Taiwan is consistent with the view that both viral and chemical factors may be involved in the process of carcinogenesis.

Areca↗
PubMed1989

Meconium peritonitis due to meconium ileus presenting as fetal ascites: a case report.

A case of meconium peritonitis due to meconium ileus is described. The condition was detected antenatally as fetal ascites on ultrasonography. Plain X-ray of abdomen post-natally showed specks of calcification mainly at the flanks, while on ultrasonography specks of high echogenic areas were seen throughout the abdomen which has been described as "snow-storm sign". The aetiology of meconium ileus is briefly discussed.

Adult↗
PubMed1989

[Elasticity and deviation angle of toothbrush in Korean adults].

The purpose of this experiment was to establish a simple and general recommendation criteria to evaluate the toothbrush whether it was usable or not. We gave 94 adults the same toothbrushes and required them to use only those toothbrushes and recollected them after 4 weeks' use. Then, we determined elasticity loss, deformation degree and deviation angle of the used toothbrushes. From the above data, we compared and analyzed the correlation between loss of elasticity loss and deviation angle. The obtained results were as follows: 1. In Korean adults, there was no statistical difference between elasticity loss and deviation angle according to both age and sex group (p greater than 0.05). 2. There was no statistical correlationship between elasticity loss and deviation angle (r = 0.15, p greater than 0.05). 3. It was regarded that the determination of deviation angle was more simple method than that of elasticity loss for the evaluation of useful period of toothbrush. 4. In Korean adults, the average usable period of toothbrush was estimated about 1 month.

Adult↗
PubMed1988

Degenerative spondylolisthesis and degenerative scoliosis treated with a combination segmental rod-plate and transpedicular screw instrumentation system: a preliminary report.

Fourteen patients with degenerative spondylolisthesis and three patients with degenerative scoliosis, all of whom experienced low-back pain, lumbar radiculopathy, and/or intermittent claudication were treated with posterolateral fusion and correction of deformities using a new instrumentation system. This new spinal fixation system combines the advantages of a rod for scoliotic deformities and a plate for sagittal plane disorders. The combination rod-plates can apply multiple forces to facilitate correction of complex deformities as well as enable indirect neurologic decompression. The system allows segmental rigid fixation via transpedicular screws that is limited only to the abnormal vertebral levels to preserve the maximum number of uninvolved lumbar motion segments. The physiologic lumbar lordotic curvature is also preserved. The minimum follow-up period was 1 year. Satisfactory results were obtained in 15 patients (88%). No intraoperative complications occurred. Screw fatigue occurred in two patients at 1-year follow-up examination with no sequelae. The scoliotic and spondylolisthetic deformities were reduced significantly in all patients. This method appears to assist in reducing pathologic motion and deformities that contribute to low-back pain. Compression on neural structures is relieved by thorough decompression and distraction; spinal canal anatomy is also restored.

Adult↗
PubMed1988

A comparative biomechanical study of spinal fixation using the combination spinal rod-plate and transpedicular screw fixation system.

A biomechanical study was performed comparing the stiffness and stability of the three-level combination spinal rod-plate and transpedicular screw (CSRP-TPS) fixation system with those of three anterior stabilization constructs that spanned three vertebral levels: iliac strut grafting, polymethylmethacrylate and anterior Harrington rod instrumentation (technique of Siegal et al.), and the Kaneda anterior device. The CSRP-TPS fixation system was also compared with five posterior instrumentation systems that spanned five vertebral levels: Harrington distraction rod instrumentation, segmentally wired Luque rectangular instrumentation, Cotrel-Dubousset transpedicular instrumentation. Steffee transpedicular screws and plates, and R. Roy-Camille plates under conditions of single-level instability. The relative stability of each instrumentation system was compared by mounting the fixation systems on calf spine segments containing five motion segments destabilized by complete L3 anterior corpectomies and L2-L3 and L3-L4 anterior diskectomies to simulate the two-column instability found clinically in spine fractures. Mechanical nondestructive cyclical testing in rotation, axial compression, and flexion was performed on 12 spines. All biomechanical tests were performed on a biaxial servo-controlled MTS 858 Bionix hydraulic materials testing device with a biaxial load cell. Intervertebral displacements between L2 and L4 were continuously recorded utilizing an extensometer with the knife edges placed directly adjacent to the L3 corpectomy defect during testing. This biomechanical study showed that CSRP-TPS instrumentation spanning three vertebral levels could restore the torsional, compressive, and flexural rigidity of the destabilized calf spines to that of the intact calf spines and provided more in vitro stability than either the traditional five-level Harrington distraction rod or the segmentally wired Luque rectangular instrumentation. The greatest torsional rigidity occurred with the five-level Cotrel-Dubousset instrumentation, the five-level Steffee plate and screw system, and the three-level Kaneda anterior device. In axial compression and flexural testing, the three-level CSRP-TPS system provided fixation comparable with the five-level Cotrel-Dubousset instrumentation, the five-level Steffee transpedicular screw and plate system, the five-level R. Roy-Camille plate and screw system, and the three-level Kaneda anterior device. Satisfactory levels of rigidity can be restored by three-level CSRP-TPS instrumentation under conditions of single-level instability in unstable thoracolumbar and lumbar spine fractures.

Analysis of Variance↗
PubMed1987

Tuberculous liver abscess.

Tuberculous liver abscess is uncommonly seen in our experience. We report a case of a 17-year-old boy who presented with typical clinical features of liver abscess, where a diagnosis of tuberculous liver abscess was made on laparotomy and biopsy of the abscess wall.

Adolescent↗