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Biomedical subjects

H J Yang

Publications and source records attributed to H J Yang.

At least 55 records · Page 3Linked to original sources
PubMed1998

Gliomatosis cerebri: clinical features, treatment, and prognosis.

To clarify clinical features and to elucidate prognostic factors and prognosis, the authors retrospectively analyzed 16 cases of gliomatosis cerebri treated at Seoul National University Hospital between January 1988 and December 1995. Age at diagnosis ranged from 19 to 62 (median 34) years and male to female ratio was 10:6. Most presented with headache or seizure, and the mean duration of symptoms was 12.8 months. A poorly defined diffuse high signal intensity lesion, extending in T2-weighted images for two lobes or more, was the characteristic magnetic resonance (MR) image finding. On postcontrast T1-weighted MR imaging, focal enhancement of the lesion was detected in five cases. All patients underwent histological confirmation by craniotomy (9 cases) or stereotactic biopsy (7 cases). Histologically, all patients had compatible findings of gliomatosis cerebri which are the widespread infiltration of neoplastic glial cells with minimal destruction of pre-existing structures. After histological diagnosis, external radiation therapy was begun except in one case, who declined this treatment. Fourteen patients completed the whole procedure and received the planned dose (mean 5780 cGy). Median survival time after diagnosis was 38.4 months. In univariate analysis, the Ki-67 labelling index (> 1) showed significant correlation with the length of survival (p = 0.006). It is suggested that 1) gliomatosis cerebri can be diagnosed by a combination of MR imaging findings and histological examination; 2) histological diagnosis and external radiation therapy might be a good treatment modality; 3) the Ki-67 labelling index correlates significantly with survival time.

Adult↗
PubMed1998

Immunoblot analysis of a 10 kDa antigen in cyst fluid of Taenia solium metacestodes.

The diagnostic value of a 10 kDa subunit of 150 kDa protein in cyst fluid (CF) of Taenia solium metacestodes was evaluated. Immunoblot analysis revealed that most sera from patients with neurocysticercosis recognized the 10 kDa subunit strongly (209/217 cases, 84.6%), while a few sera from individuals with other parasitic diseases including alveolar echinococcosis (AE, 2/20, 10%) and cystic echinococcosis (CE, 2/25, 8%) showed faint reactions. Sera of cases with other parasitic diseases, especially AE and CE, exhibited cross reactions against other bands in CF. Both differential immunoblot and immunoprecipitation analyses showed that the 10 kDa subunit was the most specific to cysticercosis and highly antigenic, whereas other components at 20-40, 64, 95 and 106 kDa in CF were cross-reactive. IgG subclass ELISA and immunoblot demonstrated that both IgG4 and IgG1 reactions were predominant in neurocysticercosis and recognized the 10 kDa.

Animals↗
PubMed1998

Immunoglobulin G (IgG) subclass and IgE responses in human paragonimiases caused by three different species.

In 40 cases of human paragonimiases caused by Paragonimus westermani (20 cases), P. miyazakii (10 cases), and P. skrjabini (10 cases), responses of serum immunoglobulin G (IgG), IgG subclasses, and IgE were analyzed by immunoblotting with crude antigens prepared from egg, 4-week-old juvenile, and adult forms of P. westermani. The 32- and 35-kDa proteins in the adult extracts showed specific reactions regardless of the causative species (39 of 40 cases; 98%). Sera of patients infected with P. westermani and P. miyazakii reacted strongly with the 28-, 46-, and 94-kDa proteins of egg extracts, while those from patients infected with P. skrjabini reacted faintly. No sera from patients with other trematodiases (0 of 15 cases), cestodiases (0 of 20 cases), or lung cancer (0 of 5 cases) or from healthy controls (0 of 10 individuals) showed positive reactions. Analysis by IgG subclass revealed that IgG4 (33 of 40 cases; 83%) and IgG1 (29 of 40 cases; 73%) antibodies in the patient sera recognized the 32- and 35-kDa proteins predominantly. IgG3 reaction was found in 50% (10 of 20 cases) and 30% (3 of 10 cases) of the sera of patients infected with P. westermani and P. miyazakii, respectively. In an IgE immunoblot, 83% (33 of 40 cases) of the sera from paragonimiasis patients reacted with the 32- and 35-kDa proteins while no sera from patients with heterologous diseases and healthy controls showed a positive reaction. Both 32- and 35-kDa proteins in adult extracts of P. westermani were highly reliable for serodiagnosis of human paragonimiases.

Animals↗
PubMed1998

Immunodiagnosis of clonorchiasis using a recombinant antigen.

A cDNA expression library of Clonorchis sinensis adult worm was constructed, and screened out immunologically. One clone, pBCs31, was selected in view of its predominant reactivity with an experimentally infected rabbit serum. Recombinant C. sinensis antigen with 28 kDa as a beta-galactosidase fusion protein produced in Escherichia coli was identified by immunoblot analysis. The cloned gene was composed of 16 copies of a 30 base pair repeat and an additional 320 bases. The deduced amino acid sequence of the tandem repeat was AQPPKSGDGG. On RNA slot blot analysis. C. sinensis adult worm RNA showed a positive reaction with the cloned gene. Enzyme-linked immunosorbent assay using a purified recombinant antigen of pBCs31 showed high specificity for diagnosis of clonorchiasis.

Amino Acid Sequence↗
PubMed1998

Immunosuppressive effect of Cryptosporidium baileyi infection on vaccination against avian infectious bronchitis in chicks.

Two-day-old commercial chicks were inoculated orally with 2 x 10(6) oocysts of Cryptosporidium baileyi and vaccinated with 10(3.5) EID50/head of a commercially available avian infectious bronchitis (IB) live virus vaccine at 4 and 14 days following inoculation. Chicks infected with C. baileyi were shown to have an immunosuppressive effect on IB virus. It is concluded that infection with the protozoon in early life may increase their susceptibility to IB.

Animals↗
PubMed1998

Verification of immunosuppression in chicks caused by Cryptosporidium baileyi infection using Brucella abortus strain 1119-3.

Humoral immune response of young chicks to Brucella abortus strain 1119-3 inoculation was monitored to verify the degree of immunosuppression caused by infection with Cryptosporidium baileyi. Young chicks (2-day-old) were orally inoculated each with 2 x 10(6) oocysts of C. baileyi, and then injected intramuscularly with 0.3 ml B. abortus strain 1119-3 containing 1 x 10(9) living organisms on day 14 postinoculation (PI). Serum samples were tested by plate agglutination test on day 17 PI onwards at an interval of 3-6 days over a period of 36 days. Infected chicks with the coccidium showed significantly lower antibody titers than those of uninfected controls (P < 0.05). These findings document that C. baileyi infection in early life stage may predispose chicks easily to other potential poultry diseases.

Animals↗
PubMed1997

Comparative evaluation on the biological monitoring of exposure to parathion and its methyl analog.

The effects of both parathion and methyl parathion on the inhibition of plasma cholinesterase were elaborated in a rat model employing a modified isocratic reverse-phase HPLC method coupled with UV detection for the determination of the urinary metabolite p-nitrophenol (U-4NP). A linearity of r2 > 0.995 was found for a standard curve ranging from 0.06 to 0.96 microg/mL with a % relative error of </= +/- 10% and a recovery of 89 +/- 2%. The % CV at all levels was </= 11%. A linear correlation was observed between the oral administration of parathion and methyl parathion for both the percent inhibiton of cholinesterase as well as the urinary elimination of 4NP. It is tentatively recommended that an U-4NP of 2. 0 mg/g creatinine be established as a biological exposure index (BEI) for methyl parathion.

Animals↗
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

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↗
PubMed1996

Intramolecular disulfide bonds enhance the antimicrobial and lytic activities of protegrins at physiological sodium chloride concentrations.

Protegrins are 2-kDa antimicrobial peptides that contain 16-18 amino acid residues and two intramolecular disulfide bonds. We studied the contribution of these disulfide bonds to the bactericidal activity of protegrins in physiological concentrations of NaCl by comparing protegrin PG-1 with variants that lacked one or both cysteine disulfides. Whereas the bactericidal and liposome-lytic properties of protegrin PG-1 were enhanced by adding 100 mM NaCl to the phosphate-buffered medium, NaCl addition strongly inhibited the effects of its linearized, disulfide-free variant, [A6, A8, A13, A15]protegrin-1. Whereas protegrin PG-1 manifested beta-sheet structure by CD (circular dichroism) and ATR-FTIR (attenuated-total-reflectance-Fourier-transform-infrared) spectroscopy in buffer or membrane-mimetic environments, [A6, A8, A13, A15]protegrin-1 manifested disordered structure in phosphate buffer and alpha-helical characteristics in membrane-mimetic environments. Both single-disulfide protegrin variants, [A8, A13]protegrin-1 and [A6, A15]protegrin-1, assumed beta-sheet conformations with liposomes that simulated bacterial membranes, and both retained substantial bactericidal activity when 100 mM NaCl was present. These findings demonstrate that the intramolecular disulfide bonds of protegrins are required for their antiparallel beta-sheet conformation in membrane-mimetic environments and for their potent antimicrobial activity in media containing NaCl concentrations comparable to those found in serum and extracellular fluids.

Amino Acid Sequence↗
PubMed1996

Heterogeneous responses to the long-term treatment of active acromegaly with octreotide.

To study GH response to the long-acting somatostatin analogue, we treated 11 actively acromegalic patients with octreotide (Sandostatin), 100 micrograms, sc, tid, for six months. Their endocrinological outcomes and clinical improvements varied. The 11-h GH secretory profiles on pretreatment day confirmed the hypersecretion of GH in all patients. Three hours after the first dose of octreotide, serum GH declined rapidly to levels below 5 ng/ml in all but two patients who failed to normalize their serum GH. In spite of the subsequent doses, there was no further suppression in serum GH. Drug resistance with GH rebound developed in some patients after three months of continued treatment. The paradoxical serum GH rises in response to oral glucose or iv TRH detected before the treatment in all patients attenuated or disappeared after the 6-month octreotide therapy; an exceptional case was one of the above-mentioned two patients, whose serum GH was stimulated more than before by glucose and TRH at the end of therapy. Serum insulin-like growth factor I (IGF-I) levels of all patients showed a significant reduction after 6-month treatment, but their mean values remained abnormally high. There were no intolerable adverse side effects; some patients, however, experienced pain at the injection site, passage of loose stool, and incidence of new gall stone or intrahepatic lesions on octreotide therapy. We concluded that octreotide was a useful long-term adjunctive therapeutic agent for patients with active acromegaly, but that a high degree of response heterogeneity including total refractoriness would be expected.

Acromegaly↗
PubMed1996

Poorly differentiated "insular" carcinoma of the thyroid: a case report.

Poorly differentiated "insular" carcinoma of the thyroid is a rare type of thyroid malignancy, situated morphologically and biologically in an intermediate position between well-differentiated (papillary and follicular) and undifferentiated (anaplastic) carcinoma. Here we report a case of a 56-year-old woman who developed a mass over the left thyroid gland in 1988, and received a thyroid operation in 1990 which was reported as benign lesion. Three years later, a mass recurred over the right lobe of the thyroid, and another thyroid operation was performed. The pathological report was medullary carcinoma. Four months later, recurrent mass over the right thyroid bed developed. Fine-needle aspiration biopsy of the mass showed moderately high cellularity with moderate pleomorphism, and multinucleated giant cells. Distinct cytoplasmic blue granules were also found in Liu's stain. She received total thyroidectomy and right neck radical dissection. Pathology examination showed well-defined nests of tumor cells ('insulae'), and immunohistochemical study showed positive stain for calcitonin. Pathologic diagnosis was poorly differentiated "insular" carcinoma of the thyroid. Four months after operation, recurrent neck mass over the suprasternal notch developed. Computerized tomography of neck and chest showed tumor mass over left thyroid bed with extension to anterior mediastinum. Whole body 131I scan showed mediastinum involvement and multiple bony metastases. Ablative 131I treatments (150 mCi and 200 mCi) were given twice, but in vain. The patient died 14 months after her last operation.

Carcinoma↗
PubMed1995

Inactivation during denaturation of ribonuclease A by guanidinium chloride is accompanied by unfolding at the active site.

Inactivation of pancreatic RNAase A occurs in guanidinium chloride (GdmCl) at low concentrations before the unfolding of the molecule as a whole can be detected [Liu and Tsou (1987) Biochim. Biophys. Acta 916, 455-464]. We have now shown that the rate of digestion of the RNAase molecule by either trypsin or proteinase K increases significantly at low concentrations of GdmCl where the enzyme is largely inactivated, but fluorescence and absorption measurements reveal no conformational changes. N-Terminal sequence analysis of the peptide fragments generated shows that proteolysis occurs primarily at or near the active site. The decrease in activity of RNAase at low concentrations of GdmCl is therefore due to partial unfolding of the molecule, particularly at the active site and not to an inhibition by the denaturant.

Amino Acid Sequence↗
PubMed1994

Sequence-ion enhancement of peptides digested with proteinase K.

Proteinase K has been employed to proteolyze peptides before their mass spectrometric analysis. This combination of the two methods yields abundant sequence ions in the mass spectrum, thus leading to an easy prediction of the primary structure of the peptide. It was found that both the variety of available sequence ions and also their abundances are increased strongly after proteinase K digestion, when compared with the normal mass spectrum. The shortcoming of little fragmentation encountered using conventional mass spectrometric ionization methods can mostly be overcome. The H'n and Y"m ions produced from proteolysis provided a double check of the peptide sequence.

Amino Acid Sequence↗
PubMed1994

Infectivity of Paragonimus westermani developing in a final host to another final host.

In the definitive hosts, metacercariae of Paragonimus westermani excyst in host duodenum, penetrate intestinal wall, migrate peritoneal and thoracic cavities, and develop to sexual maturity in 8 weeks. This study was undertaken to examine the age of the maturing P. westermani when their infectivity to the other definitive hosts was retained. On 3, 7, 10, 14, 21 and 28 days after feeding the metacercariae to cats through a gastric tube, the developing worms were harvested. The juveniles of different age were fed again to other experimental cats. One to 12 weeks after the oral-transfer infections, the experimental cats were examined for establishment of infections. In the cats to which 3-day and 7-day old juveniles (grown up to 1.4 mm long) were fed, 31.4% and 22.6% of the transferred worms were found infected. The worms of 10-28 days old were not infective. Early maturing stages grown up to 7 days maintained their infectivity to the other definitive hosts.

Animals↗
PubMed1993

Spinal congenital dermal sinus--experience of 5 cases over a period of 10 years.

Spinal congenital dermal sinus (CDS) is a rare entity which supposedly results from the failure of the neuroectoderm to separate from the cutaneous ectoderm during the process of neurulation. The lesions are most frequent at the lumbosacral followed by the occipital region. CDS of the thoracic region is very rare. The patients with spinal CDS present with meningitis and/or mass effect from the associated inclusion tumor. They are usually dermoid or epidermoid cysts. Teratoma is rarely associated. The authors experienced 5 cases of spinal CDS over a 10 year period. Of the 5 cases, 2 were at thoracic and 3 were at lumbosacral levels. Dermoid cyst, epidermoid cyst and teratoma were associated in one case each. Two cases presented with neurological deficit and meningitis while an additional case presented with neurological deficit and a history of probable meningitis. Pain was present in 2 cases. Magnetic resonance imaging played an important role in the diagnosis of the lesion and planning of surgery. All the cases showed a good response to surgery even though one patient had persistent neurological deficit.

Adolescent↗
PubMed1993

N-->S phosphoryl migration in phosphoryl glutathion.

It was found that in the case of N-(diisopropylphosphoryl) glutathion (reduced form), 2, N-->S phosphoryl migration took place, but not for N,N-bis(diisopropylphosphoryl) glutathion (oxidized form) or N-diisopropylphosphoryl cysteine. These results were deduced by 31P-NMR tracing experiments. It was shown that phosphoryl migration was catalyzed by an intramolecular carboxyl group, and a mechanism involving a mixed carboxyl-phosphoric anhydride was proposed. A competitive reaction between the amino and thiol group toward diisopropyl phosphite indicated that the phospho-thiol derived from N-(diisopropylphosphoryl) glutathion (reduced form), 2, did not result from direct phosphorylation of the thiol group. N,S-Bis(diisopropylphosphoryl) glutathion provides an authentic sample to confirm the migrated phosphoryl thiol product.

Amino Acid Sequence↗