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Biomedical subjects

Y Kong

Publications and source records attributed to Y Kong.

At least 19 recordsLinked to original sources

The MRF4 activation domain is required to induce muscle-specific gene expression.

MRF4 is a member of the basic helix-loop-helix muscle regulatory factor family that also includes MyoD, myogenin, and Myf-5. Overexpression of MRF4 or the other muscle regulatory factors in fibroblasts converts the cells to differentiated muscle fibers and transcriptionally activates expression of endogenous and cotransfected muscle genes. Although these factors induce a similar phenotype, they also exhibit some distinct biological activities. For example, MyoD trans activates alpha-actin and troponin I reporter genes to very high levels, whereas MRF4 efficiently activates only alpha-actin expression. Since these proteins have a common basic helix-loop-helix domain, it is likely that portions of the proteins outside of this region impart some specificity to the activity of each muscle regulatory factor. As an initial step in determining the mechanism by which MRF4 and MyoD activate gene transcription, the transcriptional activation domain of MRF4 has been characterized. Experiments utilizing chimeric proteins containing the yeast GAL4 DNA-binding domain and portions of the MRF4 protein indicate that the MRF4 activation domain is located within amino acids 10 to 30. This amino terminus is both necessary and sufficient to elicit a transcriptional response in transfected cells. The MRF4 activation domain and the related amino-terminal MyoD activation domain are capable of substituting for one another in converting fibroblasts to a myogenic phenotype and in activating expression of an alpha-actin reporter gene, although the MRF4 and MyoD activation domains on these chimeric proteins also dictate the specificity of transcriptional activation. The different primary amino acid sequences of these regions leave open the possibility that different coregulator proteins interact with the muscle regulatory factors to elicit their correct transcriptional activity during skeletal muscle development.

3T3 Cells

Immunohistochemical localization of 36 and 29 kDa proteins in sparganum.

Antigenic proteins of 36 and 29 kDa were localized in Spirometra mansoni plerocercoid (sparganum) immunohistochemically by avidin biotin complex (ABC) staining. When polyclonal antibodies such as BALB/c mouse serum immunized with crude saline extract of sparganum or confirmed sparganosis sera were reacted as primary antibodies, the positive chromogen (3-amino, 9-ethylcarbazole) reactions were recognized at syncytial tegument, tegumental cells, muscle and parenchymal cells and lining cells of excretory canals. A monoclonal antibody (MAb) which was reacting to 36 and 29 kDa proteins in the extract of the worm was localized at the syncytial tegument and tegumental cells. The present results suggested that the potent antigenic proteins of 36 and 29 kDa in sparganum were produced at the tegumental cells and transported to the syncytial tegument.

Animals

Detection of antibodies in serum and cerebrospinal fluid to Toxoplasma gondii by indirect latex agglutination test and enzyme-linked immunosorbent assay.

Sensitivity of anti-Toxoplasma antibody (IgG) test by enzyme-linked immunosorbent assay (ELISA) was evaluated in comparison with indirect latex agglutination (ILA) using 2,016 paired human samples of serum and cerebrospinal fluid (CSF). The samples were collected from neurologic patients in Korea with mass lesions in central nervous system (CNS) as revealed by imaging diagnosis (CT/MRI). When the sera were screened for anti-Toxoplasma antibody by ILA, 76 cases(3.8%) were positive (1:32 or higher titers). In the paired samples of CSF, no positive reactions were observed. When ELISA was performed using PBS extract of Percoll purified tachyzoites as antigen, cut-off absorbance was determined as 0.40 for serum and 0.27 for CSF tests. The antibody positive rates by ELISA were 7.0% in serum and 5.6% in CSF. Of them, 40 cases (2.0%) showed positive reactions in both serum and CSF. The antibody positive rates were higher in groups older than 40 years. The rates were higher in male (4.7% by ILA, 8.3% by ELISA) than in female (2.2% by ILA, 5.0% by ELISA). The rates in CSF showed no such sex difference. ELISA showed twice higher positive rates when serum was tested, and was sensitive enough to detect specific antibodies in CSF. Etiologic relations between positive antibody tests and CNS lesions remained unknown.

Age Factors

Tissue origin of soluble component proteins in saline extract of adult Paragonimus westermani.

Tissue origin of individual component proteins in crude extract of adult Paragonimus westermani was investigated. Major soluble component proteins were separated by disc-PAGE in 8% slab gel. By predefined Rf values, strips of gel containing each band protein was cut out. Each band protein was eluted by electrophoresis. Monospecific antibodies were prepared by immunizing rabbits with each band protein. When peroxidase-antiperoxidase (PAP) staining was done, antiserum to Band 1 reacted to content of eggs both in the worm and in the infected lung tissue. Antiserum to Band 2 reacted to parenchymal tissue of the worm. Antiserum to Band 4 showed the positive reaction at intestinal content while that to Band 5 reacted to the intestinal epithelial border. Antiserum to combined proteins of Bands 6/7 and that to Band 8 reacted to parenchymal tissue of the worm respectively. From the results, the origin of individual proteins in crude extract of adult P. westermani could be differentiated.

Animals

Immunoelectrophoretic analysis of major component proteins in cystic fluid of Taenia solium metacestodes.

When cystic fluid of Taenia solium metacestodes (CF) was filtrated through Sephacryl S-300 Superfine, major proteins were in fractions III and IV. Major protein in fraction III was Band C protein of 150 kDa and that in fraction IV was Band N protein (Choi et al., 1990). When CF was electrophoresed in 0.9% agarose gel and reacted with anti-CF rabbit serum (RACF), two main bands, a long outer and a short inner band, were precipitated, together with 8 minor bands. RACF reacted with fraction III forming the long outer band whereas RACF formed the short inner band with fraction IV in immunoelectrophoresis (IEP). The long outer precipitin band of CF fraction III was similar to antigen B in hydatid fluid (HF) of Oriol et al. (1971), while the short inner band of CF fraction IV was similar to HF antigen 5 of Capron et al. (1967). When HF was reacted with RACF, the short inner band was immunoprecipitated without forming the long outer band. Common antigenicity between CF and HF seemed to exist in fraction IV rather than in fraction III of CF. Patient sera of neurocysticercosis reacted more frequently with fraction III than with fraction IV.

Animals

Component proteins and protease activities in excretory-secretory product of sparganum.

Spirometra mansoni plerocercoid (sparganum) was incubated in saline at 4 degrees C or 37 degrees C up to 100 hours. Protein contents in the excretory-secretory product (ESP) were rather constant (mean 7.7 mg of protein/gram of sparganum) in the preparations. Reducing SDS-PAGE of ESP showed similar protein subunit compositions with those in crude extract. Antigenic 36 and 31 kDa proteins were major bands in ESP. ESP exhibited specific activities of protease (2.9-5.3 units/mg) at pH 6.0 and pH 7.5. Presence of protease activity in ESP may be a supporting evidence that hitherto known cysteine protease of sparganum is possibly secreted.

Animals

Measurement of 150 kDa protein of Taenia solium metacestodes by antibody-sandwich ELISA in cerebrospinal fluid of neurocysticercosis patients.

An antigenic protein in cystic fluid of Taenia solium metacestodes (CF) of 150 kDa was measured by antibody-sandwich ELISA in serum and cerebrospinal fluid (CSF) of neurocysticercosis patients. Capture antibodies were rabbit antisera against CF (RACF) and a monoclonal antibody (MAb) against 150 kDa protein in CF. Lower limit of antibody-sandwich ELISA was 8 ng/ml of the protein. Except CF, no tested helminths extracts reacted. Levels of the protein in 351 sera from 255 patients (55 surgery confirmed and 202 antibody and CT/MRI confirmed) were below sensitivity of the assay. Of 276 CSF from 212 patients, 31 samples (11.2%) showed positive findings. This assay, therefore, was not sensitive enough to be a diagnostic. Instead, the 150 kDa protein appeared in CSF in such situations as in 2 days after praziquantel treatment, or as in a patient infected with a racemose cysticercus with degenerated cyst wall. Of cases whose follow-up CSF were assayed, 2 cases showed that the protein appeared intermittently. These results suggest strongly that appearance of free 150 kDa protein is associated with cyst wall rupture. In CSF which contained the 150 kDa protein over 61 ng/ml, the protein was recognized in SDS-PAGE before and after immunoprecipitation.

Animals

[A study of genetic polymorphism of isozymes in natural populations of Drosophila virilis in east China].

A study of genetic variation at Est-alpha, Est-beta, A my, Acph and alpha-Gpdh loci in local samples of Hefei, Wuhu, Jiujiang, Nanchang, Changzhou, Fuzhou and Quanzhou Drosophila virilis population is presented. The employment of standard techniques of polyacrylamide electrophoresis and agarose electrophoresis reveals that the former three loci are highly polymorphic in all these populations. According to the allelic frequency of the 5 loci, a genetic distance between the above-mentioned populations was calculated. Along with the results obtained by Mr He Chaozheng from Hongze, Nanjing, Hangzhou and Ningbo populations, a dendrogram was made. It was found that Quanzhou and Fuzhou populations differed from the others in allelic frequencies and genetic distances which suggests that this difference is related to the extent of geographic isolation among them.

Animals

Radioautographic study on DNA synthesis of the retina and retinal pigment epithelium of developing mouse embryos.

We report the changes of proliferative activity of the retina and retinal pigment epithelium (RPE) of mouse embryos by detecting cells in the S-phase by light microscopic radioautography using 3H-thymidine. The eyes germs of mouse embryos at the embryonic days 9.5 (E 9.5), E 11.5, E 13.0, E 15.5, E 18.5 of gestational ages, were used for this experiment. Small pieces of the ocular tissues were labelled with 3H-TDR in vitro and light microscopic radioautographs were prepared. The labeling indices of the respective regions of tissues were calculated. Both tissues of retina and RPE showed high percentages of labeling indices from 10% to 50% through the developmental stages. The labeling indices of both tissues in earlier stages were generally higher than those of later stages, and gradually decreased in the later stages. However, the retina and RPE showed different courses of the changes of labeling indices respectively during the embryonic development. In the retina, the labeling indices in the vitreal portions were more than those in the scleral portions during the earlier developmental stages. However, in the later stages, the indices of scleral portions were more than those in the vitreal portions. Comparing the three regions of retina, the labeling indices of the anterior regions were generally higher than those of the equatorial and posterior regions, especially in the vitreal portion. Remarkable differences among three regions were not found in the scleral portion. In the RPE, the labeling indices gradually increased in the anterior region, but decreased in the equatorial and the posterior regions through all the developmental stages. The proliferation of both retina and RPE in the central region occurred earlier than those of the peripheral region.

Animals

Differential localization of protein kinase C isozymes in retinal neurons.

We report the immunohistochemical localization of protein kinase C isozymes (types I, II, and III) in the rabbit retina using the monospecific monoclonal antibodies MC-1a, MC-2a, and MC-3a. Using immunoblot analysis of partially purified protein kinase C preparations of rabbit retina, types II and III isozymes alone were detected. The activity of type III was the stronger. By light microscopic immunohistochemical analysis, retinal neurons were negative for type I and positive for type II and type III isozymes. Type II was more diffusely distributed through the retinal layers, but was distinctive in ganglion cells, bipolar cells, and outer segments. The immunoreactivity was stronger for type III isozyme, and it was observed in mop (rod) bipolar cells and amacrine cells. By using immunoelectron microscopy, the cytoplasm of the cell body, the axon, and dendrites of the mop bipolar cells were strongly immunoreactive for type III. The so-called rod bipolar cells were for the first time seen to form synapses with rod photoreceptor cells. These differential localizations of respective isozymes in retinal neurons suggest that each isozyme has a different site of function in each neuron.

Animals

Single step purification of potent antigenic protein from sparganum by gelatin-affinity chromatography.

Out of many component proteins in crude saline extract of Spirometra mansoni plerocercoid (sparganum), 36 kDa and 29 kDa proteins were found to be the most antigenic and were already purified by immunoaffinity chromatography using monoclonal antibody as a ligand. In this study, a single step purification of these potent antigenic proteins of sparganum extract was investigated. When the crude saline extract was charged to gelatin-Sepharose 4B affinity column, 36 kDa and 29 kDa protein fractions were bound. SDS-polyacrylamide gel electrophoresis (PAGE) and SDS-PAGE/immunoblot confirmed that the bound protein to gelatin was serologically pure. When evaluated by ELISA with patients sera, the purified protein of 36 and 29 kDa also showed improved antigenicity.

Animals

Molecular weight of major component proteins in crude saline extract of adult Paragonimus westermani.

When the component proteins in crude saline extract of 13-week old adult Paragonimus westermani were observed by non-denaturing discontinuous-polyacrylamide gel electrophoresis (Disc-PAGE), 8 distinct bands were clearly recognized. Molecular weight (MW) of each band protein, numbered in sequence from cathodal side which appeared in 10% separating gel, was measured first by Ferguson plot utilizing different gel concentrations from 10% to 4.5%. MW of band 1 protein (known as egg protein) was 440 kDa. And MW of other band proteins were: 386 kDa in band 2, 17.4 kDa in band 3, 17 kDa in band 4, 14.3 kDa in band 5, 46 kDa in band 6, 38 kDa in band 7 and 23 kDa in band 8. When the proteins in the crude extract were separated into fractions by molecular sieve chromatography through 1.6(phi) X 70 cm sized Sephacryl S-300 Superfine column and revisualized by Disc-PAGE in 8% gel, the sequence of eluted proteins was band 1, band 2, band 6, band 7 and bands 3, 4, 5 and 8. This elution profile confirmed MW of each band protein in the crude extract as measured by Ferguson plot.

Animals

Metacercarial infections of Paragonimus westermani in freshwater crabs sold in markets in Seoul.

Status of metacercarial infections of Paragonimus westermani was observed in freshwater crabs, which were purchased at 3 markets in its peak season of 1990. All of 85 crabs were Eriocheir japonicus. No other species of Eriocheir were found. When crushed muscle and viscera was examined individually, the infection rate was 11.8%; and mean number of metacercariae was 2.1 per infected crab. Unless adequately cooked, freshwater crabs are still potential sources of human paragonimiasis.

Animals

Purification and characterization of a Cu, Zn-superoxide dismutase from adult Paragonimus westermani.

In cytosolic fraction of adult Paragonimus westermani, superoxide dismutase activity was identified (4.3 units/mg of specific activity) using a xanthine-xanthine oxidase system. The enzyme was purified 150 fold in its activity using the ammonium sulfate precipitation, DEAE-Trisacryl M anion-exchange chromatography and Sephadex G-100 molecular sieve chromatography. The enzyme exhibited the enhanced activity at pH 10.0. The enzyme activity totally disappeared in 1.0mM cyanide while it remained 77.8% even in 10 mM azide. These findings indicated that the enzyme was Cu, Zn-SOD type. Molecular mass of the enzyme was estimated to be 34 kDa by gel filtration and 17 kDa on reducing SDS-polyacrylamide gel electrophoresis which indicated a dimer protein.

Animals

Component proteins in crude extract of adult Paragonimus westermani purified by immunoaffinity chromatography using monoclonal antibodies.

The nature of 2 component proteins in crude saline extract of adult Paragonimus westermani was investigated. By immunoaffinity chromatography using monoclonal antibodies (MAb) as ligands, the proteins were purified from the crude extract. Band 1 protein in disc-polyacrylamide gel electrophoresis (PAGE) was purified by PFCK-136 MAb. The protein, known to have molecular mass of 440 kDa, was composed of 23, 46 and 92 kDa subunits when observed by reducing SDS-PAGE and SDS-PAGE/immunoblot. This protein was originated from eggs of the worm as revealed by immunohistochemical staining with PFCK-136 Mab. Another affinity purified protein utilizing PFCK-44 MAb was the band 4 protein of 17 kDa in disc-PAGE. This was a monomer protein in reducing SDS-PAGE and SDS-PAGE/immunoblot. The protein was produced at intestinal epithelium of the worm.

Animals

Subcutaneous fascioliasis: a case report.

A 32-year old housewife, living in Seoul, recognized incidentally a painless mass at the left chest wall. During later 3 months, she experienced spontaneous swelling and regression of the mass repeatedly for 4 times. Surgical resection showed a granuloma at anterior serratus muscle containing a nearly matured adult of Fasciola species without vitellaria and uterus. This is the 11th human fascioliasis and the first extra-abdominal infection reported in Korea.

Adult

Component proteins in cystic fluid of Taenia solium metacestodes collected surgically from neurocysticercosis patients.

Surgically collected cystic fluid of Taenia solium metacestodes from patients of intracranial cystic lesion were compared in their protein composition with those from naturally infected pigs in Cheju Do, Korea and Ecuador. In non-denaturing discontinuous-polyacrylamide gel electrophoresis (disc-PAGE), no discernible differences were recognized in banding patterns between the cystic fluids from Cheju Do and Ecuador, and between the cystic fluids from pigs and human lesions except wider bands that corresponded to human albumin and gamma-globulin (in 4 of 9 patients). In reducing SDS-PAGE, bands in the cystic fluid from Ecuador showed the same banding pattern with that from Cheju Do but two bands of 21 and 17 kDa were stained darker. Cystic fluids from patients revealed the same protein compositions of the major protein bands of 94, 64, 15, 10 and 7 kDa as in the cystic fluid of pig origin, but human albumin (66 kDa), heavy and light chains of gamma globulin (55 and 22.5 kDa) were contaminated in 4 of 9 cystic fluids. Human CSF proteins seem to have been contaminated during cystic fluid collection. In any cystic fluid from patients, the major protein component was 150 kDa which was subdivided into 15, 10 and 7 kDa in reducing SDS-PAGE.

Adult