Biomedical subjects

Y J Shin

Publications and source records attributed to Y J Shin.

13 recordsLinked to original sources

PubMed2000

Retinoic acid and its geometrical isomers block both growth and fusion of L6 myoblasts by modulating the expression of protein kinase A.

All-trans retinoic acid (RA) and its geometrical isomers, such as 9-cis RA, 13-cis RA, and 9,13-di-cis RA, strongly inhibited both growth and fusion of L6 myoblasts. However, illumination of white light diminished their inhibitory activity on membrane fusion with little effect on cell growth. During myogenic differentiation, the intracellular level of cAMP decreased whereas the total activity of protein kinase A as well as the protein level of its regulatory subunit Ialpha (RIalpha) and catalytic subunit (Calpha) increased. RAs raised the intracellular level of cAMP by over 3-fold, but decreased the total activity of protein kinase A. Like RAs, dibutyryl-cAMP inhibited myoblast fusion and reduced the expression of both RIalpha and Calpha subunits. These results suggest that RAs negatively modulate the differentiation of L6 myoblasts by increasing the intracellular level of cAMP, which may in turn down-regulate the expression of protein kinase A and hence its activity.

Animals↗

PubMed2000

Benefits of cochlear implantation in elderly patients.

Cochlear implantation in elderly patients is a questionable subject. The purpose of this study was to evaluate the procedure and its outcome, the postoperative course, and the audiologic and social benefits of cochlear implantation in this population. Twenty-seven patients older than 60 years were compared with a control group of 15 adult patients. This retrospective study analyzed data concerning the outcome of the procedure, postoperative course, postoperative orthophonic test results, and answers of a questionnaire assessing the changes in communication, perception, and social outcomes. The procedure was uneventful in both groups. Minor complications were not more frequent in elderly patients. Orthophonic test results were comparable in both groups. At 12 months, 83% of the elderly patients had an open-set speech discrimination score above 60%. The benefits of cochlear implantation in terms of the quality of life are not statistically different with younger patients. Cost-utility analysis might support these findings.

Adult↗

PubMed2000

Pure sensorineural hearing loss and otosclerosis. An imaging case report.

Pure sensorineural hearing loss is not a rare finding in otological practice. Numerous aetiologies could be at the origin of such a deficit. However, otosclerosis is very rarely cited as a cause of pure sensorineural hearing loss. We present one such case of pure sensorineural hearing loss linked to otosclerosis in a 30-year old caucasian male and underline the high contribution of computed tomography to confirm such a diagnosis. Pure sensorineural hearing loss due to otosclerosis is a rare event and can be misdiagnosed. The clinical diagnosis of such a disease may be difficult. In these cases, CT-Scan is the exam of choice to confirm the diagnosis.

Adult↗

PubMed2000

Effectiveness of conservative management of acoustic neuromas.

OBJECTIVE: The goal of this study was to assess the effectiveness of the conservative management in patients with acoustic neuroma (vestibular schwannoma). STUDY DESIGN: This retrospective study was performed in a university hospital. PATIENTS: Patients were selected for this wait-and-see policy on the basis of age, general condition, audiometric results, tumor size, and patient preference. The study group included 97 patients, 87 of whom had at least two neuroradiologic examinations. The mean age of this population was 63 years (29 to 89 years). The mean length of follow-up of this population was 31 months. Eighty-seven of these patients had at least two radiologic examinations (magnetic resonance imaging or computed tomography). The mean interval between the initial and follow-up radiologic examinations was 15 months. MAIN OUTCOME MEASURES: Tumor size was measured by use of two-dimensional data in all patients. The mean tumor size was 12 mm. The growth rate of the tumor was estimated by comparison of the results of the measurements from the initial and follow-up neuroradiologic examinations. RESULTS: Of the 97 patients studied, 6 patients required surgery and 6 required radiotherapy. Sixty patients (62%) were still being treated conservatively at the end of the study period. Three patients of 28 who were classified as candidates for hearing preservation surgery lost their candidacy during the observation period. The mean annual tumor growth rate was 1.52 mm/year. The tumor was stable in size in 36% of patients, regressed in 11% of patients, or grew in 53% of patients. The growth patterns of the acoustic neuroma fell into five categories: continuous growth in 15% of patients, negative growth in 5%, growth followed by negative growth in 40%, negative growth followed by growth in 20%, and no variation of tumor size in 20%. CONCLUSION: Conservative management of acoustic neuromas carries difficulties: long-term follow-up of the patients and unpredictability of the tumor growth pattern. A reliable and reproducible radiologic method for evaluating tumor size is of great importance.

Adult↗

PubMed1999

Perfusion impairments in infantile autism on technetium-99m ethyl cysteinate dimer brain single-photon emission tomography: comparison with findings on magnetic resonance imaging.

The neuro-anatomical substrate of autism has been the subject of detailed investigation. Because previous studies have not demonstrated consistent and specific neuro-imaging findings in autism and most such studies have been performed in adults and school-aged children, we performed a retrospective review in young children in search of common functional and anatomical abnormalities with brain single-photon emission tomography (SPET) using technetium-99m ethyl cysteinate dimer (ECD) and correlative magnetic resonance imaging (MRI). The patient population was composed of 23 children aged 28-92 months (mean: 54 months) who met the diagnostic criteria of autism as defined in the DSM-IV and CARS. Brain SPET was performed after intravenous injection of 185-370 MBq of 99mTc-ECD using a brain-dedicated annular crystal gamma camera. MRI was performed in all patients, including T1, T2 axial and T1 sagittal sequences. SPET data were assessed visually. Twenty patients had abnormal SPET scans revealing focal areas of decreased perfusion. Decreased perfusion of the cerebellar hemisphere (20/23), thalami (19/23), basal ganglia (5/23) and posterior parietal (10/23) and temporal (7/23) areas were noted on brain SPET. By contrast all patients had normal MRI findings without evidence of abnormalities of the cerebellar vermis, cerebellar hemisphere, thalami, basal ganglia or parietotemporal cortex. In conclusion, extensive perfusion impairments involving the cerebellum, thalami and parietal cortex were found in this study. SPET may be more sensitive in reflecting the pathophysiology of autism than MRI. However, further studies are necessary to determine the significance of thalamic and parietal perfusion impairment in autism.

Autistic Disorder↗

PubMed1999

Comparison of Korean-American adoptees and biological children of their adoptive parents: a pilot study.

This study compared a small group of Korean-American adoptees with their adoptive siblings who are biological children of the adoptive parents with respect to their psychosocial adjustment. Eighteen Korean-American adoptees were compared with nine biological children by a structured demographic, medical, clinical survey form and the Child Behavior Checklist-Parent Form (CBCL-P). The parents did not raise any more concerns about the adjustment of adopted children than their biological children. On the CBCL-P, the two groups did not differ significantly in competence T-scores, total behavioral problems, broad and T-scores and the total number of problem behaviors except for lower social competence in adopted children and a higher internalization score in biological children. In conclusion, the international adoptees, the Korean-American children have adjusted well during their early childhood after early adoption. Further studies employing a larger sample are warranted to better understand the international adoption practice.

Adolescent↗

PubMed1999

Analysis of the precore and core promoter DNA sequence in liver tissues from patients with hepatocellular carcinoma.

To investigate the role of mutant hepatitis B virus (HBV) in the development of hepatocellular carcinoma (HCC), 20 patients with HCC were studied for precore and core promoter mutations in tumorous and nontumorous tissues. The precore and core promoter region was amplified and analyzed by direct sequencing. Among the 20 tumorous and nontumorous tissues, precore mutant HBV was found in 12 (60%) and 18 (90%), respectively. Of the 12 tumorous tissues with precore mutant, nine tissues had a single mutation (1896) and one tissue had another single mutation (1899). The remaining two tissues had a double mutation (1896 and 1899). A single mutation (1896) and a single mutation (1899) were found in 11 and two of the 18 nontumorous tissues with precore mutant, respectively. Among 20 tumorous and nontumorous tissues, HBV with a C to T mutation at nucleotide (nt) 1846 was detected in six and eight, respectively, and was associated with the virus carrying a mutation (1896 or 1899) except in two tumorous tissues. Mutations at nt 1762 and 1764 in core promoter were observed in 16 (80%) tumorous tissues and 18 (90%) nontumorous tissues. Mutations in the precore and core promoter region were found frequently in nontumorous tissue and in tumorous tissue (18/20 and 12/20 in precore region, 18/20 and 16/20 in core promoter respectively). The high prevalence of precore and core promoter mutations in liver tissue from patients with HCC suggests that these mutations may contribute to the development of HCC.

Adult↗

PubMed1998

Localization of hepatitis B virus DNA in hepatocellular carcinoma by polymerase chain reaction in situ hybridization.

The polymerase chain reaction in situ hybridization (PCR-ISH) is a new technique that combines the sensitivity of PCR with the localizing ability of ISH. To investigate the expression pattern of hepatitis B virus (HBV) in the tissue of hepatocellular carcinoma (HCC), we detected HBV-DNA with PCR-ISH in paraffin-embedded tumor and corresponding non-tumor tissues from 11 HCC patients. HBV-DNA was detected in 4 of 11 tumor tissues and in 7 of 10 non-tumor tissues. In tumor tissues, positive signals were scattered in the tissue with occasional clustering, and were found mainly in the cytoplasm of HCC cells rather than in the nucleus. In non-tumor tissues, the number of positive signals was higher than in tumor tissues and they were found in regenerating nodules with differing patterns and intensities. When we compared the detection rate of PCR-ISH with nested PCR among 10 tissue samples, HBV-DNA was detected in 5 tissue samples by PCR-ISH, but the S gene was detected in 10, precore gene in 9 and X gene in 8 by nested PCR. The findings suggest that PCR-ISH is a sensitive technique for localizing HBV in tissue sections and that the low level of HBV replication persists in HCC cells.

Carcinoma, Hepatocellular↗

PubMed1998

Hearing restoration in posterior fossa tumors.

OBJECTIVE: This study aimed to assess the results of hearing restoration with a cochlear or a brainstem implant in posterior fossa tumors. PATIENTS: Six patients were selected. Two patients with an acoustic neuroma in the only-hearing ear (cases 1 and 2), one patient with a posterior fossa meningioma (case 3), one patient with bilateral facial neuroma (case 4), and two patients with bilateral acoustic neuroma (cases 5 and 6) participated. INTERVENTION: In cases 1 and 2, the patients had a cochlear implant inserted on the only-hearing ear opposite the acoustic neuroma. In case 3, the patient presented with total deafness on the left side and a 10-mm meningioma on the right side. A cochlear implantation was performed after removal of the meningioma on the right side. In case 4, the patient was operated on on both sides with bilateral postoperative deafness. A cochlear implantation was performed on the better hearing ear. In cases 5 and 6, patients underwent an auditory brainstem implantation after the exeresis of the second tumor. RESULTS: Promontory test results were positive for patients 1, 2, 3, and 4. After implantation, patients 1, 2, 3, and 4 scored 98%, 13%, 70%, and 30%, respectively, in open-set sentence recognition tests, whereas patients 5 and 6 scored 0% and 20%, respectively. CONCLUSIONS: In case of nonfunctional cochlear nerve, in acoustic neuroma, either bilateral and in the only-hearing ear, promontory test should be performed. If positive results, a cochlear implantation should be performed, because successful results could be expected. Overall results of cochlear implantation on speech discrimination are better than those obtained with a brainstem implant.

Adolescent↗

PubMed1998

[Adenoid cystic carcinoma of the larynx. A case report and review of the literature].

Laryngeal adenoïd cystic carcinoma (ACC) is a rare disease due to the poor distribution of the accessory salivary glands in this area. The authors describe a case of ACC arising from the sus glottic area and underline the difficulty of such a diagnosis, which is in fact an histologic finding. The signs of discovery of a laryngeal ACC are not different from other tumors of the area, except pain frequently evoked in these tumors. Laryngeal ACC arises exceptionally before the age of 20 years and no risk factor is known. The most frequent localization is in the sub-glottic area, but sus glottic and glottic localizations have been reported. Evolution is marked by the onset of cervical lymph adenopathies and systemic metastasis most often located in the lung. The treatment comprises wide surgical exerisis followed by radiotherapy. Other reports seem to indicate that the pronostic of the laryngeal location of this disease is worse than in other areas of the head and neck.

Aged↗

PubMed1997

[Cochlear implants in the elderly].

The authors present a retrospective and multicenter study of 18 elderly patients aged above 60 years-old who underwent a cochlear implantation by comparing them with a population of adult patients. The purpose of this study is to evaluate the utility and benefits of cochlear implantation in the elderly by analyzing the clinical data and the results of a questionnaire assessing the use of the implant and the consequences of implantation on the quality of life. The results of this study indicate that the improvement of quality of life in the elderly is similar compared to a control group of adult patients.

Aged↗

PubMed1997

[Conservation of residual hearing after cochlear implantation].

Indications for cochlear implantation have been expanded to include severely hearing impaired adults and may increase the number of patients presenting with preoperative residual hearing. Conservation of residual hearing may allow better performance with an implant. However, conventional thought is that implantation destroys auditory structures involved in residual hearing. This study was undertaken to assess if there are general or surgical factors intervening in the conservation of residual hearing in a sample of multichannel implant recipients. A retrospective study on 50 adult cochlear recipients with preoperative residual hearing has been undertaken. Sixteen of 50 implanted subjects (32%) were found to have conserved their residual hearing. Among them, seven patients have clinically non-significant changes of hearing. Age, side of implantation, gender and etiology did not influence the outcome of residual hearing. Round window ossification, ossification of the cochlea, length of insertion, approach and site of insertion (scala tympani vs.scala vestibuli) were not found to be statistically significant between the population having lost and the population having conserved residual hearing. This study emphasizes the need to undertake a larger multicenter longitudinal study to determine the existence of factors related to the conservation of residual hearing.

Adolescent↗

PubMed1996

Toxoplasma antibody titers by ELISA and indirect latex agglutination test in pregnant women.

The seroepidemiologic studies on anti-Toxoplasma antibody titers were carried out using ELISA and indirect latex agglutination test. Among 899 sera prepared from pregnant women, 39 cases (4.3%) revealed positive reaction and 218 sera from middle school students showed 4 positive reaction (1.8%) by ELISA. By LAT (newly established by National Veterinary Research Institute. Korea), the sera of 7 pregnant women (0.8%) showed positive reaction. When 80 sera showing > or = 1:8 by LAT were used for comparing the results obtained from LAT and Toxotest-MT (Eiken Chemical Co., Japan), 7 cases and 8 sera were positive, respectively. All of 11 sera of proven toxoplasmosis patients showed positive reaction in both tests. Overall proportion of agreement between LAT kit and Toxotest-MT was 0.94 (kappa-index = 0.632, p < 0.011, and LAT was considered to be useful for the screening of toxoplasmosis.

Adolescent↗