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Biomedical subjects

S Jung

Publications and source records attributed to S Jung.

205 records · Page 12Linked to original sources
PubMedDate not supplied

Co-expression of nestin and vimentin intermediate filaments in invasive human astrocytoma cells.

Intermediate filaments (IFs) are highly diverse intracytoplasmic proteins within the cytoskeleton which exhibit cell type specificity of expression. A growing body of evidence suggests that IFs may be involved as collaborators in complex cellular processes controlling astrocytoma cell morphology, adhesion and proliferation. As the co-expression of different IF subtypes has been linked to enhanced motility and invasion in a number of different cancer subtypes, we undertook the present study to examine the expression of vimentin and nestin in a panel of human astrocytoma cell lines whose tumorigenicity, invasiveness and cytoskeletal protein profiles are well known. Astrocytoma cells were examined for IF protein expression by immunofluorescence confocal and immunoelectron microscopy. The motility of all cell lines was determined by computerized time-lapse videomicroscopy. Invasive potential of astrocytoma cells was determined using Matrigel as a barrier to astrocytoma cell invasion in vitro. Vimentin was expressed by all astrocytoma cell lines. On the other hand, nestin was variably expressed among the different cell lines. The most motile and invasive astrocytoma cell line in our study was antisense GFAP-transfected U251 (asU251) astrocytoma cells which showed marked up-regulation of nestin expression compared to the U251 parental cell line and controls. The U87 astrocytoma cell line also demonstrated high nestin expression levels and was associated with an increased basal motility rate and a high degree of invasiveness through Matrigel. U343 astrocytoma cells did not express nestin, but had high levels of GFAP. It had the lowest motility rate and invasiveness of all the astrocytoma cell lines examined. Taken together, these data suggest that for the astrocytoma cell lines examined in this study, nestin and vimentin co-expression may serve as a marker for an astrocytoma cell type with enhanced motility and invasive potential. Further studies are required to determine the mechanism by which dual-IF protein expression alters other cytoskeletal or cell surface receptor protein components important in the process of astrocytoma invasion.

Astrocytoma↗
PubMedDate not supplied

Stent-induced intimal hyperplasia: are there fundamental differences between flexible and rigid stent designs?

PURPOSE: To evaluate possible differences in neointimal development resulting from overdilation of rigid versus flexible vascular stents. MATERIALS AND METHODS: Twelve vascular sheaths were placed bilaterally through femoral arteries in six swine. After angiographic measurement, 12 stents (six flexible and six rigid) were balloon expanded to 8-mm diameters in 12 6-mm iliac arteries (approximately 30% overdilation). All stents were similar in surface area, gauge, and type of wire (tantalum). The primary difference was longitudinal flexibility (low hoop strength) versus rigidity (high hoop strength). Stents were studied with angiography and intravascular ultrasound 5 weeks after implantation. The animals were killed, and the stented segments were removed and examined histologically. RESULTS: Rigid stents maintained larger diameters than flexible stents: mean, 6.52 mm versus 5.82 mm (mean difference, 0.70; standard deviation [SD], 0.47; confidence interval [CI], +/- 0.49; P < .05). In addition, rigid stents developed a thicker, eccentric neointimal reaction relative to flexible stents: mean 1.08 mm versus 0.74 mm (mean difference, 0.338; SD, 0.315; CI, +/- 0.331; P < .05). CONCLUSION: Rigid stents maintain larger diameters over the long term relative to flexible stents when overdilated in normal swine arteries. However, a thicker neointima develops within the lumen of rigid stents at follow-up (greater late loss).

Animals↗
PubMedDate not supplied

The phylogenetic relationship of possible progenitors of the cultivated peanut.

The cultivated peanut (Arachis hypogaea L.) is an allotetraploid composed of A and B genomes. The phylogenetic relationship among the cultivated peanut, wild diploid, and tetraploid species in the section Arachis was studied based on sequence comparison of stearoyl-ACP desaturase and oleoyl-PC desaturase. The topology of the trees for both fatty acid desaturases displayed two clusters; one cluster with A genome diploid species and the other with B genome diploid species. The two homeologous genes obtained for each of the two fatty acid desaturases from the tetraploid species A. hypogaea and A. monticola were separated into the A and B genome clusters, respectively. The gene phylogenetic trees showed that A. hypogaea is more closely related to the diploid species A. duranensis and A. ipaensis than to the wild tetraploid species A. monticola, suggesting that A. monticola is not a progenitor of the cultivated peanut. In addition, for the stearoyl-ACP desaturase, the A. duranensis sequence was identical with one of the sequences of A. hypogaea and the A. ipaensis sequence was identical with the other. These results support the hypothesis that A. duranensis and A. ipaensis are the most likely diploid progenitors of the cultivated tetraploid A. hypogaea.

Amino Acid Sequence↗
PubMedDate not supplied

The incidence and clinical characteristics of Mycobacterium tuberculosis infection among systemic lupus erythematosus and rheumatoid arthritis patients in Korea.

OBJECTIVES: The aim of this study was to describe the incidence and clinical characteristics of Mycobacterium tuberculosis infection in SLE and RA patients in Korea where the prevalence rate of active pulmonary tuberculosis in a general population is relatively higher than in Western countries. PATIENTS: We reviewed the medical records of 283 SLE and 284 RA patients retrospectively and then assessed the incidence, risk factors, and clinical characteristics of active tuberculous infection. We then compared the results for the two different groups. RESULTS: Tuberculosis was documented in 15 SLE and 7 RA patients with an incidence rate of 7.9/1,000 patient-years and 2.3/1,000 patient-years, respectively (p = 0.003). SLE-associated tuberculosis cases included 3 of miliary tuberculosis, 7 of pulmonary tuberculosis (including 1 case of diffuse pulmonary involvement with meningitis) predominantly involving two or more lobes at the mid-/lower lungfield, and 5 extra-pulmonary forms (joint, bone, kidney, larynx, pleura). All of the RA-associated tuberculosis cases were pulmonary forms with the majority being localized to single lobe, and only one case had a past history of tuberculosis, whereas a past history of tuberculosis and a longer duration of the underlying disease were significantly correlated with the development of tuberculosis in the SLE patients. Major organ involvement, the mean daily dosage of prednisolone, and a history of over 30 mg of daily prednisolone were not related to the development of tuberculosis. However, when we took only those patients taking corticosteroid until the diagnosis of tuberculosis for analysis, SLE patients with tuberculosis showed a higher daily dosage of prednisolone than those without tuberculosis. CONCLUSION: Taken together, the characteristics of tuberculosis in SLE patients were: (1) a higher incidence rate, (2) more frequent extra-pulmonary involvement, (3) more extensive pulmonary involvement, and (4) a higher relapse rate than in rheumatoid arthritis. Thus, the contributory role of M. tuberculosis infection in the morbidity and mortality of patients with SLE must be emphasized, especially in areas in which this bacteria is endemic.

Adolescent↗