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Biomedical subjects

J H Nam

Publications and source records attributed to J H Nam.

At least 37 records · Page 2Linked to original sources
PubMed2000

Induction of tumor immunity and cytotoxic T lymphocyte responses using dendritic cells transfected with messenger RNA amplified from tumor cells.

Unique patient-specific tumor antigens may constitute the dominant antigens in the antitumor immune response. Hence, vaccination with the patient's own repertoire of tumor antigens may offer a superior strategy to elicit protective immunity. We have shown previously that dendritic cells transfected with mRNA isolated from tumor cells stimulate potent CTL responses and engender protective immunity in tumor-bearing mice. In the current study, we demonstrate that tumor mRNA, isolated from murine tumor cell lines or from primary human tumor cells microdissected from frozen tissue sections, can be amplified without loss of function. This study provides the foundations for an effective and broadly applicable treatment that does not require the characterization of the relevant antigenic profile in each patient and will not be limited by tumor tissue availability for antigen preparation.

Animals↗
PubMed2000

Intravascular papillary endothelial hyperplasia in the kidney of a child.

Intravascular papillary endothelial hyperplasia (IPEH) is a benign vascular lesion which is thought to represent an unusual form of organizing thrombus. A case of IPEH in the kidney of a 7-year-old girl is described. She suffered from intermittent flank pain and gross hematuria for 6 months. On radiological examinations, well-defined hypoechoic lesions were identified in the medullary portion of the left kidney. A well-demarcated, sponge-like mass was noted on gross examination. It was an intravascular mass lined by a fibrous capsule of various thicknesses. It was characterized by papillary fronds lined with benign endothelial cells. This is the first description of a renal IPEH in a child.

Child↗
PubMed2000

Blood fatty acid composition of pregnant and nonpregnant Korean women: red cells may act as a reservoir of arachidonic acid and docosahexaenoic acid for utilization by the developing fetus.

Relative fatty acid composition of plasma and red blood cell (RBC) choline phosphoglycerides (CPG), and RBC ethanolamine phosphoglycerides (EPG) of pregnant (n = 40) and nonpregnant, nonlactating (n = 40), healthy Korean women was compared. The two groups were of the same ethnic origin and comparable in age and parity. Levels of arachidonic (AA) and docosahexaenoic (DHA) acids were lower (P < 0.05) and palmitic and oleic acids higher (P < 0.0001) in plasma CPG of the pregnant women. Similarly, the RBC CPG and EPG of the pregnant women had lower AA and DHA (P < 0.05) and higher palmitic and oleic acids (P < 0.01). The reduction in DHA and total n-3 fatty acids in plasma CPG of the pregnant women was paralleled by an increase in docosatetraenoic (DTA) and docosapentaenoic (DPA) acids of the n-6 series and in DPA/DTA ratio. In the RBC phospholipids (CPG and EPG) of the pregnant women, DTA and DPA acids of the n-6 series and DPA/DTA ratio did not increase with the decrease of the n-3 metabolites (eicosapentaenoic acid, DPA, and DHA) and total n-3. Since pregnancy was the main identifiable variable between the two groups, the lower levels of AA and DHA in RBC CPG and EPG of the pregnant women suggest that the mothers were mobilizing membrane AA and DHA to meet the high fetal requirement for these nutrients. It may also suggest that RBC play a role as a potential store of AA and DHA and as a vehicle for the transport of these fatty acids from maternal circulation to the placenta to be utilized by the developing fetus.

Adult↗
PubMed2000

Texture luminance judgments are approximately veridical.

This paper investigates intensity coding in human vision. Specifically, we address the following question: how do different luminances influence the perceived total luminance of a composite image? We investigate this question using a paradigm in which the observer attempts to judge, with feedback, which of two texture patches has higher total luminance. All patches are composed of nine luminances, ranging linearly from 0 (black) to a maximum luminance (white: 160 cd/m(2) in one condition; 20.2 cd/m(2) in another condition). Luminance histograms of the patches being compared are experimentally varied to derive, for each luminance nu, the impact exerted by texture elements (texels) of luminance nu on texture luminance judgments. We find that impact is approximately proportional to texel luminance; That is, a texture element exerts, on average, an impact on texture brightness (i.e. perceived texture luminance) that is proportional to its (the texel's) luminance. The only exception occurs for texels of maximal luminance, which surprisingly exert an impact that is slightly, but significantly, less than that exerted by texels of the next lower luminance. We conclude that visual intensity coding for purposes of assessing overall luminance of inhomogeneous patches is approximately veridical. In particular, texture luminance judgments are not mediated by a significant, compressive nonlinearity.

Contrast Sensitivity↗
PubMed2000

Variance of high contrast textures is sensed using negative half-wave rectification.

A rectifying transformation is required to sense variations in texture contrast. Various theoretical and practical considerations have inclined researchers to suppose that this rectification is full-wave, rather than half-wave. In the studies reported here, observers are asked to judge which of two texture patches has higher texture variance. Textures are composed of small squares, with each square being painted with one of nine different luminances. Different texture variances are achieved by manipulating the histograms of the texture patches to be compared. When the nine luminances range linearly from 0 to 160 cd/m(2), the transformation mediating judgments of texture variance takes the form of a negative half-wave rectifier: texture variance judgments are determined exclusively by the frequencies of luminances below mean luminance in the textures being compared. However, when the nine luminances range linearly from 60 to 100 cd/m(2), two of three observers use a full-wave rectifying transformation in making texture variance judgments; the third observer continued to use a negative half-wave rectifier. The unexpectedly asymmetric roles played by low versus high luminances in texture variance judgments suggest that the off-center system may play a dominant role in human perception of texture contrast.

Contrast Sensitivity↗
PubMed2000

Identification of glucokinase mutation in subjects with post-renal transplantation diabetes mellitus.

Mutations in the glucokinase (GCK) gene are considered to be a possible cause of maturity-onset diabetes of the young. The purpose of this study was to evaluate the contribution of this gene to the development of post-renal transplantation diabetes mellitus (PTDM). Identification of the GCK mutation was attempted in 58 selected renal allograft recipients with PTDM and 45 normal controls. The exons in the GCK gene were examined using polymerase chain reaction (PCR), followed by an analysis of single-stranded DNA conformational polymorphism (SSCP). The abnormal bands were then confirmed by DNA sequencing analysis. The family members of the patients affected with GCK mutation were also examined. Two of the 58 PTDM patients (3. 4%) were found to have GCK mutations. One had the mutation on exon 5 and the other on intron 7. One control subject had the mutation on intron 9. The mutation on exon 5 was identified as a substitution of CCT (proline) for CTT (leucine) at codon 164, which has never been reported before. The family members of the PTDM patient with a mutation on exon 5 were analyzed by PCR, followed by SSCP, and two of them had the same mutation. The abnormal band seen on SSCP analysis of exon 7 was identified as the C-->T substitution at the 39th nucleotide in intron 7. Two of the family members also displayed the same bands on the SSCP. One of the 45 normal controls had a known polymorphism located at the 8th nucleotide in intron 9. We found a GCK mutation on the exon in subjects with PTDM and we speculate that this mutation may be one of the possible contributing factors of PTDM, although variations of the GCK gene are not common causes of PTDM.

Adult↗
PubMed2000

Pregnancy reduces arachidonic and docosahexaenoic in plasma triacylglycerols of Korean women.

Plasma triacylglycerol (TG) fatty acid composition of healthy non-pregnant and non-lactating women, expectant mothers and their term neonates from Seoul, South Korea was investigated. They were ethnically homogeneous and the women had comparable age and parity. Blood samples were obtained at recruitment, third trimester and birth from the non-pregnant women, expectant mothers and neonates respectively. Percent levels of linoleic and arachidonic acids and n-6 metabolites and total n-6 were significantly lower in the pregnant women than in the non-pregnant (p < 0.0001). Similarly, there were lower levels of alpha-linolenic (p = 0.033), eicosapentaenoic and docosahexaenoic acids and n-3 metabolites and total n-3 (p < 0.0001) in the expectant mothers. Compared with their mothers, the neonates had higher proportions of dihomo-gamma-linolenic, arachidonic, docosatetraenoic and docosapentaenoic acids and n-6 metabolites (p < 0.0001) and lower linoleic acid (p < 0.0001). Of the n-3 series, alpha-linolenic acid was lower (p < 0.0001) and eicosapentaenoic, docosapentaenoic and docosahexaenoic acids and n-3 metabolites and total n-3 higher (p < 0.0001) in the neonates compared with their mothers. The study reveals that pregnancy is associated with a reduction in the relative levels of plasma triacylglycerol arachidonic and docosahexaenoic acids. Moreover, it indicates that the decline is a manifestation of selective transfer of these fatty acids to the developing fetus.

Adult↗
PubMed2000

The progression of mediastinal lymphangioma in utero.

We describe a case of mediastinal lymphangioma that suddenly progressed in utero. The initial sonographic impression was one of pericardial effusion while the follow-up examination revealed a mediastinal cystic mass. At 35 weeks of gestation preterm labor occurred. An ultrasound examination performed at this time demonstrated the mediastinal cyst with internal hemorrhage and fetal hydrops. The cystic mass was resected 5 days after birth. The diagnosis of lymphangioma was made from histological examination. The infant was followed up for 18 months and remained well. We recommend frequent prenatal sonographic follow-up when a localized fluid collection is, shown in the mediastinum.

Adult↗
PubMed2000

Relationship between endometrial estrogen and progesterone receptors, and sonographic endometrial appearance in the preovulatory phase.

OBJECTIVES: The purpose of the present study is to evaluate the relationship between endometrial concentrations of estrogen receptor (ER) and progesterone receptor (PR), and sonographic endometrial findings in the preovulatory phase of menstrual cycle. STUDY DESIGN: In 45 cycles of 45 infertile women with tubal factor only, transvaginal sonographic assessments and biopsy for immunohistochemical staining of the endometrium were made in the preovulatory phase of unstimulated, normal menstrual cycle. Immunohistochemical localization of ER and PR was scored according to intensity of staining and proportion of cells specifically stained in glandular epithelium and stroma, and the results were analysed according to the sonographic endometrial thickness (< 6 mm, 6-10 mm, or > 10 mm) and patterns. Endometrial patterns were classified as A, centrally hyperechogenic triple-line pattern or non-A, not triple-line. RESULTS: There were no significant differences in the endometrial thickness, serum estradiol level and serum progesterone level between A and non-A groups. The receptor scores of epithelial and stromal ER and epithelial PR were comparable in A and non-A groups. However, the receptor score of stromal PR was significantly higher in A group, with 4.8 +/- 1.4 compared with 2.7 +/- 1.7 in non-A group (p < 0.001). There were no differences in the receptor scores of epithelial ER, epithelial PR, stromal ER and stromal PR among the 3 groups according to the endometrial thickness. CONCLUSIONS: This study suggests that high PR expression in endometrial stroma could be related to the sonographic triple-line or multilayered pattern of endometrium in the preovulatory period.

Adult↗
PubMed2000

Apoplexy of pituitary macroadenoma after combined test of anterior pituitary function.

Pituitary apoplexy has been reported as a very rare complication of combined tests of anterior pituitary function and of TRH or gonadotropin-releasing hormone (GnRH) administration in pituitary tumor. A 34-year-old man with a GH-secreting pituitary macroadenoma and diabetes mellitus received an injection of 400 microg TRH, 100 microg GnRH, and 0.15 U/Kg regular insulin. Twenty minutes later, he complained of a severe headache and vomited. Visual acuity and visual field did not change and his headache was persistent during the next 24 hours of conservative management. Magnetic resonance imaging (MRI) of the sella turcica done the day after the event showed definitive elevation of the optic chiasm and slight enlargement of tumor and focal areas of mixed high signal and low signal intensities in the macroadenoma on noncontrast T1-weighted images. Headache subsided markedly within a day of octreotide therapy. Transsphenoidal removal of the pituitary tumor was performed 9 days after the hormone study. Ischemic necrosis and hemorrhage were confirmed in the acidophilic adenoma with positive immunostaining for GH. Postoperative course was uneventful and his serum insulin-like growth factor-1 (IGF-1) level and blood glucose levels were normalized. Three months after the surgery the dynamic test was repeated without adverse effects. To our knowledge, this is a very rare case of apoplexy of GH-secreting pituitary adenoma after a combined stimulation test of anterior pituitary function.

Acromegaly↗
PubMed1999

Protection against lethal Japanese encephalitis virus infection of mice by immunization with the highly attenuated MVA strain of vaccinia virus expressing JEV prM and E genes.

Genes encoding the glycosylated precursor of the membrane (prM) and envelope (E) proteins of a Korean strain of Japanese encephalitis virus (JEV) were inserted into the genome of the host-range restricted, highly attenuated, and safety-tested MVA strain of vaccinia virus. MVA recombinants containing the JEV genes, under strong synthetic or modified H5 vaccinia virus promoters, were isolated. Synthesis of JEV prM and E proteins was detected by immunofluorescence microscopy, flow cytometry, and polyacrylamide gel electrophoresis. Mice inoculated and boosted by various routes with either of the MVA recombinants produced JEV neutralizing antibodies, that had titres comparable with those induced by an inactivated JEV vaccine, as well as haemagglutination-inhibiting antibodies. Mice immunized with 2 x 10(6) infectious units of MVA/JEV recombinants by intramuscular or intraperitoneal routes were completely protected against a 10(5) LD50 JEV challenge at 9 weeks of age.

Animals↗
PubMed1999

Influence of incisional complications on infrainguinal vein bypass graft outcome.

Incisional complications following infrainguinal vein bypass remain a formidable challenge to the vascular surgeon. A retrospective analysis of 250 infrainguinal vein bypass grafts (214 patients) was undertaken to identify risk factors for the development of incisional complications and determine the impact of incisional complications on outcome. Incisional complications occurred in 47 (19%) of the bypasses. The mean age was 67.8 years and 155 (62%) of the bypasses were performed in men. The patients were divided into two groups based on the presence or absence of an incisional complication. By univariate analysis, the contributing factors for an incisional complication were: veteran hospital status, dialysis dependence, anemia, obesity, leukocytosis, and hypoalbuminemia (p < 0.05). By multivariate analysis, veteran hospital status, female gender, leukocytosis, and prior ipsilateral bypass were independent risk factors for incisional complications (p < 0.05). The increased incidence of incisional complications in the veteran's hospital group was associated with anemia, leukocytosis, decreased lymphocyte count, and increased incidence of tissue loss (p < 0.05). By life-table analysis, incisional complications did not influence primary patency (p = 0.73), secondary patency (p = 0.91), limb salvage (p = 0.69), or survival (p = 0.92). However, a significant suppurative soft-tissue infection ultimately resulted in a high rate of major amputation.

Aged↗
PubMed1999

Malignant phyllodes tumor of the prostate.

Phyllodes tumor of the prostate is rare. We have recently experienced a case of phyllodes tumor of the prostate in a 57-year-old man who complained of urinary retention for 1 year. The epithelial components were positive reactivity for prostate specific antigen. The stromal cells showed nuclear atypia with increased mitotic activity. The tumor was diagnosed as a malignant phyllodes tumor as it invaded into the urinary bladder and rectum, and grew rapidly immediately after operation. We describe the morphological features and immunohistochemical findings of malignant phyllodes tumor and review the literature.

Biomarkers, Tumor↗
PubMed1997

Km genotyping using polymerase chain reaction-allele specific oligonucleotide in Koreans.

The allotype of human immunoglobulin kappa light chain constant region gene (IGKC) has been identified by the serological assay or DNA typing method. The three allotypes Km*1, Km*1,2 and Km*3 have amino acid substitutions at positions of codons 153 and 191 in the kappa light chain constant region. The Km allotypes were designated as follows: Km*1 has valine (GTC) at position 153 and leucine (CTC) at 191; Km*1,2 has Ala153 (GCC) and Leu191 (CTC); Km*3 has Ala153 (GCC) and Val191 (GTC). In this study, polymerase chain reaction-allele specific oligonucleotide (PCR-ASO) was used to provide a specific allelic typing system for the IGKC gene in 213 unrelated Koreans. For Km genotyping, the IGKC coding regions plus 35 bp of the 3' untranslated regions were amplified with specific primers. Amplified genes were hybridized with Km ASO probes at positions of codons 153 and 191 and were detected using a colorimetric detection method. The frequencies of Km*1,2/Km*1,2, Km*1,2/Km*3, and Km*3/Km*3 were 17.8% (n=38), 51.7% (n=110), and 30.5% (n=65), respectively. The estimated allele frequencies for Km*1,2 and Km*3 were 0.44 and 0.56, respectively. The homozygote or the heterozygote of Km*1 was not observed in this study. The PCR-ASO method distinguished the alleles Km*3, Km*1,2, and Km*1 and also distinguished the homozygote from heterozygote. Km frequencies vary significantly among various populations. Km*3 in Koreans was very similar to those observed in northern Chinese, Japanese, and the native people of British Columbia. It was lower than that reported in Caucasian, Indian, or southern Chinese.

Amino Acid Sequence↗
PubMed1997

Neuronal differentiation of human neuroblastoma SH-SY5Y cells by gangliosides.

Exogenous administration of gangliosides induced neuronal differentiation with prominent neuritogenesis in human neuroblastoma SH-SY5Y cells in vitro. Neuritogenesis was characterized by ruffling of the cell membrane, the development of lamellipodia and filopodia, and the subsequent elongation and branching of the neurites ultrastructurally. Both axons and neurites were identified. Increased numbers of cell organelles in the neurites and cell bodies were noted. Nonsynaptic contacts and gap junctions formed between neurites or between each neurite and cell body. These findings could be implicated in histopathologic changes from neuroblastoma to ganglioneuroblastoma.

Cell Differentiation↗