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Biomedical subjects

S Y Cho

Publications and source records attributed to S Y Cho.

At least 127 records · Page 7Linked to original sources
PubMed1997

Activities of different cysteine proteases of Paragonimus westermani in cleaving human IgG.

Cleaving host immunoglobulins is a well known mechanism of evading host immune reactions exploited by helminth parasites. Secreted cysteine proteases of helminth are a part of enzymes cleaving host IgG. Paragonimus westermani produces at least six different species of the cysteine protease in its developmental stages. This study was undertaken to evaluate comparatively the activities against human IgG by the different enzymes. When the metacercariae, which secrete 27 and 28 kDa cysteine proteases, were incubated in human IgG solution, IgG was degraded at its hinge region. Further incubation resulted complete hydrolysis. From 4-week and 7-week old juveniles and 16-week old adults of P. westermani, five different enzymes at 15, 17, 27, 28 and 53 kDa have been purified, if the enzyme with the same molecular mass is regarded to be identical. In cleaving human IgG, each cysteine protease exhibited decreasing activities with age.

Animals↗
PubMed1997

Variation of antigenic proteins of eggs and developmental stages of Paragonimus westermani.

Diagnosis of early paragonimiasis is difficult because parasitological evidence is not easily obtained. Antibody tests have been proposed as a good substitute for classical diagnostic techniques. Using the crude extracts of Paragonimus westermani eggs, metacercariae, 4- and 7-week juveniles, and 16-week adults as antigens, we observed the early antibody responses. Sera were obtained from 4 experimental cats, fed 50 metacercariae each, at intervals until 13 weeks post-infection. Antibody (IgG) responses were identified by ELISA using extracts of 4-week juveniles, followed by those of 7- and 16-week worms. Antibody responses were minimal against the metacercarial extracts. Antibodies to P. westermani egg extracts were elevated after 10 weeks post-infection. In immunoblot analysis, more than nine protein bands in 4-week juveniles reacted with the early infection sera. Antigenic proteins in adult worms were different from those of juveniles. After four weeks of infection, 32 and 35 kDa bands in the adult extracts were increasingly reactive. Egg specific proteins at 28, 46 and 94 kDa were reactive only after 10 weeks. Antigenic components reacting to the early infection sera changed during the maturation stages of P. westermani; almost all juvenile antigens were replaced by adult antigen components.

Animals↗
PubMed1997

A small epidemiological survey for vivax malaria in Kimpo-gun, Kyonggi-do, Korea undertaken after detecting two consecutive cases.

On July and August 1997, two 15-year-old mates of a football team of Tongjin Middle School in northern Kyonggi-do, Korea were consecutively diagnosed as vivax malaria by peripheral blood smear. They had no histories of travelling abroad or drug abuse. They witnessed that other mates in the team were ill of fever in the same period. A small survey was therefore undertaken to determine whether vivax malaria was outbroken locally. A total of 57 students of the team living together in a dormitory was examined for history of fever, presence of splenomegaly, blood smear and anti-P. vivax antibody test by immunofluorescent antibody test (IFAT). Except for the above two patients, only one case revealed a marginal titer of IFAT. No other positive findings of vivax malaria were found. In the results of this local survey, no more cases of vivax malaria were revealed except the two sporadic cases.

Adolescent↗
PubMed1997

Cysteine protease activities during maturation stages of Paragonimus westermani.

In mature Paragonimus westermani, specific activity of parasitic cysteine protease declines. To clarify which of the known 17-, 27-, and 28-kDa enzyme activities is decreased, the cysteine proteases were purified from the crude extracts of metacercariae, 4- and 7-wk juveniles, and 16-wk adults by gel filtration, ion-exchange, and affinity matrix chromatographies; the enzyme activity was monitored with the fluorogenic substrate, Cbz-phe-arg-AMC. In addition to 3 known enzymes, 2 other cysteine proteases at 15 and 53 kDa were identified in juveniles and adults and were purified. The 2 novel enzymes were most active in 0.1 M ionic strength and pH 5-6 and were inhibited by N-(N-[L-3-transcarboxyrane-2-carbonyl]-L-leucyl)agamatine, iodoacetamide, and leupeptin. Of the 5 enzymes, specific activities of metacercarial 27- and 28-kDa enzymes were lowered from metacercaria to 16 wk. Between 4 and 16 wk, activities of 3 cysteine proteases of juveniles and adults were additionally exhibited. The activity changes of 5 different cysteine proteases may be associated with migration and immune evasion during the maturation stage of P. westermani when the parasite environment is changing.

Animals↗
PubMed1997

Epidemiology of paragonimiasis in Korea.

In Korea, soybean-sauce soaked freshwater crabs (kejang) have been a favorite delicacy when eating a bowl of rice. This traditional food has been a main source of human paragonimiasis. Until the late 1960s, human paragonimiasis had been prevalent; at least two million people had contracted the infection as determined by intradermal tests. About 40% of these were egg positive. In the turmoil of the green revolution and industrialization in the 1970s/1980s, ecological damage occurred widely. In many streams, populations of snail and crustacean hosts were reduced to levels almost of extinction. Population reduction of the intermediate hosts was followed by lowered endemicity. Attitudes of people, changed during the period, also reduced chances of paragonimiasis. Survey data in the 1990s indicated that prevalence of human paragonimiasis has lowered to about one 100th of that in the early 1970s. In a referral system, however, about one hundred clinical cases have been diagnosed annually by antibody test (ELISA), undertaken for clinical differentiation from tuberculosis. At least 10% of freshwater crabs sold in local markets are infected with the metacercariae. Paragonimiasis control has benefited in Korea mainly by the untoward effects of water pollution. To place P. westermani infections as enzootic, health education and surveillance systems should have a priority.

Animals↗
PubMed1996

Role of muIP-10 in interferon-gamma induction of Ia in rat astrocytes.

Interferon-gamma, (IFNgamma) is a potent inducer of class II MHC (Ia) in rat astrocytes and microglia which are immunocompetent cells of the central nervous system (CNS). muIP-10, a member of the alpha-chemokine family, is also induced by IFNgamma in these cells. The induction of muIP-10 mRNA occurred in an immediate early manner, while Ia mRNA-induction was delayed and required new protein synthesis. We studied the possible role of muIP-10 in IFNgamma-mediated induction of Ia in astrocytes. Antibodies to muIP-10 protein significantly inhibited the expression of surface Ia molecules by astrocytes. Incubation of astrocytes with antisense-oligonucleotides against muIP-10 mRNA also reduced the number of Ia positive cells inducible by IFNgamma. Neither the number of IFNgamma-inducible class I MHC positive cells nor the number of class I molecules expressed per cell were affected by antisense-oligonucleotides against muIP-10, indicating the specificity of the oligonucleotide and the selective requirement of muIP-10 for Ia induction by IFNgamma. Transient transfection of astrocytes with plasmids expressing muIP-10 in the antisense orientation also reduced the number of Ia positive astrocytes. These studies suggest a role for muIP-10 protein as an autocrine factor that enhances the expression of IFNgamma-inducible Ia on astrocytes. This could create focal areas rich in Ia expressing cells which could more efficiently present antigens to T cells, leading to immune-mediated inflammation such as in multiple sclerosis.

Animals↗
PubMed1996

The role of insulin resistance in Korean patients with coronary atherosclerosis.

To determine whether dietary modification improves insulin resistance and coronary atherosclerosis, we randomly assigned 14 Korean patients to an experimental group (low-fat, low-cholesterol diet, high polyunsaturated/saturated fatty acid ratio, and calorie restriction) or to a control group (no dietary change). Coronary artery lesions were analyzed by quantitative coronary angiography, and postglucose insulin responses were measured. At baseline, there were no significant differences in body weight, BMI, waist-to-hip ratio (WHR), and plasma lipid and insulin levels between the two groups. After completion of the 1-year diet program, the experimental group showed significant reductions in body weight (66.0 +/- 3.2 to 61.6 +/- 3.8 kg [means +/- SE], P < 0.01) and WHR (O.96 +/- 0.01 to 0.93 +/- 0.01, P < 0.05). Total cholesterol (5.45 +/- 0.45 to 4.50 +/- 0.44 mmol/l, P < 0.05), LDL cholesterol (3.71 +/- 0.36 to 2.98 +/- 0.37 mmol/l, P < 0.05), and triglyceride (1.91 +/- 0.28 to 1.29 +/- 0.17 mmol/l, P < 0.05) were also significantly reduced in the experimental group. The mean insulin response during an oral glucose tolerance test was also significantly decreased (258.6 +/- 26.4 to 181.8 +/- 6.6 pmol/l, P < 0.05). In contrast, there were no significant changes in these parameters in the control group. When only coronary artery lesions > 50% stenosed were analyzed, the average percentage diameter stenosis regressed from 63.2 to 56.8% in the experimental group. However, there were no significant changes in the control group. Our trial suggests that decreases in body weight and WHR and an improvement in insulin resistance with a low-fat, low cholesterol diet and caloric restriction may reduce risk factors and reverse coronary atherosclerotic lesions in 1 year.

Body Composition↗
PubMed1996

Analysis of antigenic domain of GST fused major surface protein (p30) fragments of Toxoplasma gondii.

Antigenic domain of major surface protein (p30) of Toxoplasma gondii was analyzed after polymerase chain reaction (PCR) of its gene fragments. Hydrophilic or hydrophobic moiety of amino acid sequences were expressed as glutathione S-transferase (GST) fusion proteins. Fragments of p30 gene were as follows: T37, total p30 open reading frame (ORF); S28, total ORF excluding N-terminal signal sequence and C-terminal hydrophobic sequence: A19, N-terminal 2/3 parts of S28; P19, C-terminal 2/3 of S28; X9, N-terminal 1/3 part of S28; Y10, middle 1/3 of S28; and Z9, C-terminal 1/3 of S28, respectively. Primer of each fragment was synthesized to include clamp sequence of EcoR I restriction site. PCR amplified DNA was inserted into GST (26 kDa) expression vector, pGEX-4T-1 to transform into Escherichia coli (JM105 strain). GST fusion proteins were expressed with IPTG induction as 63, 54, 45, 45, 35, 36, and 35 kDa proteins measured by SDS-PAGE. Each fusion protein was confirmed with GST detection kit. Western blot analysis with the serum of a toxoplasmosis patient revealed antigenicity in proteins expressed by T37, S28, and A19 but not those by P18, X9, Y10, and Z9. Antigenicity of p30 seems to be located either in N-terminal 1/3 part in the presence of middle 1/3 part or in the oligopeptides between margins of the first and second 1/3 parts.

Amino Acid Sequence↗
PubMed1996

Real-time determination of left ventricular ejection fraction by automatic boundary detection in patients with dilated cardiomyopathy: a comparison with radionuclide ventriculography.

Echocardiographic automatic boundary detection (ABD) is a new on-line technique which automatically outlines the left ventricular endocardial border and instantly calculates the left ventricular area and volume from two dimensional echocardiographic images. To determine if left ventricular ejection fraction (LVEF) can be derived using the ABD method, 25 consecutive patients with dilated cardiomyopathy, aged 52.1 +/- 15.2 (range 14 approximately 75), underwent complete echocardiographic examination with both the ABD method and radionuclide ventriculography (RVG). End-diastolic and end-systolic left ventricular areas were obtained on-line from the apical four chamber view. Left ventricular length was also measured from an apical view. Left ventricular volumes and ejection fraction were calculated using the single plane area-length method. ABD measurements could be obtained in all patients. Linear regression analysis compared ejection fraction derived by ABD and RVG. The mean radionuclide LVEF was 20.9 +/- 6.8% and mean ABD-derived LVEF was 22.7 +/- 5.8%. Linear regression analysis revealed that the ABD-derived LVEF is closely correlated with the RVG-derived LVEF (r = 0.87, p < 0.001). In conclusion, ABD echocardiography is a new on-line technique which may be used to accurately calculate LVEF in patients with dilated cardiomyopathy.

Adolescent↗
PubMed1996

Serum levels of antioxidant vitamins in relation to coronary artery disease: a case control study of Koreans.

With the changes in trends of disease pattern from infectious to chronic degenerative disease, cardiovascular disease has been considered as the major cause of death in Korea. Numerous studies have been done on the antioxidant effects of some vitamins in the prevention of chronic illness, but not many in relation to the cardiovascular disease. Therefore, the relation between antioxidant vitamins, mainly alpha-tocopherol (alpha-T) and beta-carotene (beta-C), and coronary artery disease (CAD) such as angina pectoris and myocardial infarction has been investigated in this study. The blood samples were obtained from the CAD patients who were angiographically diagnosed within a month (100 case group). Patients who had an experience of PTCA or CABG were excluded from the study. Control subjects were healthy adults who had normal EKG values, no chest pain and no past history of cardiac disease (100 control group). All subjects were free for serum lipid lowering drugs. Serum alpha-T and beta-C were analysed using HPLC. In addition to antioxidant vitamins, serum lipids (total cholesterol, HDL, TG) were also measured. Each case and control was matched in terms of age and sex. And all the CAD risk factors such as blood pressure, smoking, alcohol, serum lipid profile and BMI were adjusted to determine pure effect(s) of alpha-T and beta-C on the CAD. The concentrations of both alpha-T and beta-C were significantly lower in the CAD group than those in control group (P < 0.05); in CAD group, mean values of alpha-T and beta-C were 11.9 +/- 7.2 (micrograms/ml), 35.8 +/- 3.1 (micrograms/dl) respectively. As for the levels of beta-C, it shows inverse relation with age, but not for the alpha-T levels. Serum levels of both vitamins did not show any significant differences in terms of sex, but men have a tendency o higher levels of beta-C, but lower levels of alpha-T.

Adult↗
PubMed1995

Lymphadenitis in experimental murine toxoplasmosis induced by intramuscular injection of tachyzoites.

When tachyzoites (RH strain) of Toxoplasma gondii are injected intramuscularly, experimental mice survive up to 7 days, 1-2 days longer than those infected intraperitoneally. We observed sequential histopathological changes in inguinal lymph nodes after intramuscular injection of tachyzoites to thighs of specific pathogen free (SPF) mice. Initial findings on 1 or 3 days after the injection were reactive germinal centers, distended sinuses and epithelioid cell clusters in cortical and paracortical regions. Later on 5 days after the injection, however, effacement of nodal structure with depletion of cells and focal necrosis were observed. Necrotizing lymphadenitis in the experimental murine toxoplasmosis suggests the causal relation between T. gondii infection and the human disease.

Animals↗
PubMed1995

A case of tick bite by a spontaneously retreated Ixodes nipponensis.

A 58-year old housewife consulted us about 1 cm sized, dark-brownish, bean-like mass which was dropped spontaneously from indurated skin lesion on her abdomen. The mass was identified morphologically as an engorged female Ixodes nipponensis. Nine days earlier, she had an excursion collecting edible sprouts of wild grass. Spontaneous retreat has been unusual in clinical tick bites in Korea. Fourteen cases of tick bite described in the Korean literature were reviewed briefly in relation to Lyme borreliosis.

Animals↗
PubMed1995

A cysteine protease of Paragonimus westermani eggs.

Protease activity was identified in crude extracts of Paragonimus westermani eggs which were purified from infected dog lungs, isolated on 14 weeks after metacercarial challenge. The eggs were used after removing possibly contaminated host or worm tissues on their shell surfaces. In the crude egg extracts, high proteolytic activities against carboxybenzoyl-phenylalanyl-arginyl-4-methoxy-beta-naphthylamide (Cbz-phe-arg-MNA) and Azocoll were detected whereas those against succinyl-alanyl-prolyl- phenylalanyl-p-nitroanilide (Suc-ala-pro-phe-pNA) were not revealed. The enzyme exhibited the maximal activity at pH 6. Its activity was inhibited by specific cysteine protease inhibitors, 10(-5) M 1-trans-epoxysuccinylleucylamido (4-guanidino) butane (E-64) and 1 mM iodoacetamide (IAA) while potentiated by 6.5-fold in the presence of 2.5 mM dithiothreitol (DTT). When the enzyme was purified partially by Sephacryl S-300 High Resolution gel filtration, it migrated as a single homogeneous band at 35 kDa. The 35 kDa cysteine protease has been recognized neither in the metacercariae nor in the adult. These findings indicated the presence of at least one protease of cathepsin family in immature eggs of P. westermani.

Animals↗
PubMed1995

A human case of invasive fascioliasis associated with liver abscess.

A 56 year-old Korean housewife/farmer/goat keeper suffered from right upper quadrant pain and fever with chills. In the abdominal sonogram and computerized tomography, multiple, 2-3 cm, irregular shaped cavities were observed in the right lobe of liver. A liver biopsy revealed extensive central necrosis with Characot-Leyden crystals surrounded by palisading histiocytes, eosinophil-rich inflammatory infiltration. Worm was not observed. However, the serologic test for Fasciola-specific IgG antibody by micro-ELISA was positive. Prior antibody levels did not differ and eosinophilia persisted 6 and 16 months after praziquantel treatment although the cavitary lesions in the liver disappeared 6 months after the treatment. Reported herein is a human case of invasive fascioliasis diagnosed clinically by a combination of radiological, histopathological and serological studies.

Animals↗
PubMed1995

Excystment of Paragonimus westermani metacercariae by endogenous cysteine protease.

To infect definitive or paratenic hosts, metacercariae of Paragonimus westermani should excyst in the host intestine. Optimum conditions for the excystment have been known to be pH 8-9 and a temperature of 40 C. Under these conditions, excystment of P. westermani metacercariae was accelerated in the presence of 1 mM dithiothreitol (DTT). The DTT acceleration was antagonized dose-dependently by cysteine protease inhibitors of L-trans-epoxysuccinylleucylamido(4-guanidino)butane (E-64, 2-20 microM) or leupeptin (0.1-1 mM), suggesting that certain cysteine proteases of the metacercaria are involved in excystment. Protease activities were detected in excretory-secretory products (ESP) of newly excysted metacercariae. Two distinct proteases were purified by DEAE anion-exchange chromatography of the ESP. While a 27-kDa protease exhibited endodipeptidolytic activity at pH 5-8.5 and remained stable at neutral pH for 3 days, the 28-kDa enzyme was stable at pH 5-7.5, with lower activity at pH 8.5. Both proteases hydrolyzed collagen, fibronectin, and myosin within 1 hr at pH 8. These results suggest that cysteine proteases secreted by P. westermani metacercariae modulate excystment.

Animals↗
PubMed1994

Characterization of three neutral proteases of Spirometra mansoni plerocercoid.

In the pathogenesis of sparganosis, proteases have been considered to play important roles in tissue migration and parasite feeding. Several bands of proteolysis were observed when crude extracts of Spirometra mansoni plerocercoid (sparganum) were examined using gelatin substrate gel at neutral pH, of which two proteases of 198 and 104 kDa were purified by two chromatographic steps, and a 36 kDa protease was purified by gelatin-affinity and DEAE-anion exchange chromatography. All the purified proteases exhibited optimal activity at pH 7.5 and 0.1 M Tris-HCl. Proteolytic activities at 198 and 104 kDa were inhibited specifically by serine protease inhibitors and 4-(amidinophenyl)methanesulfonyl fluoride (APMSF, 0.5 mM) and N-alpha-p-tosyl-L-lysine chloromethyl ketone (TLCK, 1 mM), which strongly suggested that these two proteases were trypsin-like proteases. The activity of the 36 kDa protease was inhibited by N-tosyl-L-phenylalanine chloromethyl ketone (TPCK, 1 mM) and chymostatin (0.1 mM), and was potentiated in 10 mM Ca2+ which showed that the protease had a chymotrypsin-like property. All the proteases were Schiff (PAS) positive. Proteases of 198 and 104 kDa degraded collagen completely within 24 h. The 36 kDa enzyme cleaved human recombinant interferon-gamma (rIFN gamma) and bovine myelin basic protein. In addition, all the purified proteins elicited strong antibody responses in the infected patients.

Animals↗
PubMed1994

Cleavage of immunoglobulin G by excretory-secretory cathepsin S-like protease of Spirometra mansoni plerocercoid.

When immunoglobulin G (IgG) was incubated with Spirometra mansoni plerocercoid (sparganum), it was cleaved into Fab and Fc fragments. Fab/c fragments were also hydrolysed. The digestion was accelerated by dithiothreitol (DTT), indicating that cleavage of IgG heavy chain was due to a cysteine protease secreted into the medium. The responsible enzyme, of M(r) 27 (+/- 0.8) kDa, was purified by a series of thiopropyl affinity, Sephacryl S-300 HR and DEAE-anion exchange chromatographies, either from worm extracts or from excretory-secretory products (ESP). The purified, thiol-dependent protease showed an optimal activity at pH 5.7 with 0.1 M sodium acetate but was active over the pH range 4.5-8.0. Its activity was inhibited completely by 10(-5) M L-trans-epoxysuccinylleucylamido(4-guanidino) butane (E-64) and 1 mM iodoacetamide (IAA), but by only 53% using the specific cathepsin L inhibitor, Z-Phe-Phe-CHN2 (5 x 10(-5) M). Partial NH2-terminal amino acid sequence was Leu-Pro-Asp-Ser-Val-Asn-Trp-Arg-Glu-Gly-Ala-Val-Thr-Ala-Val which showed 80% homology to human cathepsin S. Immunoblot analysis showed that sera from infected patients exhibited IgE antibody reaction. It is proposed that cleavage of immunoglobulin by an excreted-secreted, cathepsin S-like, allergenic protease is a mechanism of immune evasion used by the sparganum.

Amino Acid Sequence↗