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Biomedical subjects

R J Chen

Publications and source records attributed to R J Chen.

At least 109 records · Page 6Linked to original sources
PubMed1990

Cross-reactivity among antigens of different air-borne fungi detected by ELISA using five monoclonal antibodies against Penicillium notatum.

Cross-reactivity among antigens of 12 genera of air-borne fungi, 13 species of Penicillium, and 5 species of Aspergillus was studied by ELISA using five monoclonal antibodies (MoAbs) against Penicillium notatum. Epitopes recognized by all the five MoAbs were susceptible to treatment of mild periodate oxidation and may therefore be associated with carbohydrates. Furthermore, our results showed that there is cross-reactivity among antigens of Penicillium, Aspergillus, and Eurotium species. By using these MoAbs, cross reactivity was not detected between antigens of Penicillium notatum and antigens of Fusarium solani, Alternaria porri, Cladosporium cladosporoides, Curvularia species, Nigrospora species, Aureobasidium pullulans, Wallemia species, Rhizopus arrhizus, and Candida albicans. Cross-reactivity among antigens of 11 species of Penicillium and 5 species of Aspergillus could be detected by ELISA using one of the five MoAbs (MoAb P15). The fact that there may be cross-reactivity among antigens of closely related fungi species should be considered in the diagnosis and treatment of mold allergic diseases.

Air Microbiology↗
PubMed1990

[Histopathological observations on orbital fatty tissue in dysthyroid ophthalmopathy].

Seventeen specimens of orbital fatty tissue taken from cases of dysthyroid ophthalmopathy at the time of operation were observed by light and electron microscopy, and also by immunohistochemical staining. The pathological changes observed were infiltration of the chronic inflammatory cells, deposit of fibrin, sclerosis of vascular wall, occlusion of the vascular lumen, and accumulation of hydrophilic mucopolysaccharide. Immunoglobulin G was detected in fat cells and lymphocytes, and some of the infiltrating lymphocytes were determined to be T cells, by immunohistochemistry. These findings suggested that the pathology of the dysthyroid ophthalmopathy was closely related to the chronic inflammation induced by the immune reaction. The exophthalmos was considered to occur due to edema secondary to chronic inflammation and accumulation of the mucopolysaccharides.

Adipose Tissue↗
PubMed1989

Human chorionic gonadotropin and its subunits in pre-eclampsia.

The serum levels of hCG and its subunits were studied in 11 cases of pre-eclampsia (8 cases of severe pre-eclampsia and 3 cases of mild pre-eclampsia) and 72 normal pregnant women. The hCG (human chorionic gonadotropin) immunoactivity measured by H80 RIA (radioimmunoassay) and Sb6 RIA showed no significant difference between pre-eclampsia and normal pregnancy. This result suggests that no significant amount of free hCG-beta existed, since H80 RIA measured intact hCG but not hCG-beta, and Sb6 RIA measured both hCG and hCG-beta. Furthermore, from the result of elution behavior of gel HPLC (high performance liquid chromatography), hCG of pre-eclampsia and comparison of the Sb6 RIA/H80 RIA ratio between pre-eclampsia and normal pregnancy, it was evident that there was little amount of free hCG-beta secretion in pre-eclampsia as in normal pregnancy. However, the free hCG-alpha was significantly higher in severe pre-eclampsia, probably caused by placental dysfunction. In summary, free hCG-alpha is increased in pre-eclampsia, but its role as a marker of placental function in pre-eclampsia requires further investigation.

Chorionic Gonadotropin↗
PubMed1988

"Otodental" dysplasia.

The case of a 3 11/12-year-old Chinese boy with the dental abnormalities of "otodental" dysplasia is reported. Hearing was normal. Dental anomalies consisted of delayed eruption of globe-shaped molars, bulbous deciduous canines, and double pulp chambers in the molars. Radiographs taken 4 years later showed taurodontic molars, supernumerary microdontic teeth, retarded formation of premolars, and probable aplasia of the mandibular second premolars.

Child↗
PubMed1988

Production of monoclonal antibodies to human chorionic gonadotropin.

Production of monoclonal antibodies against human chorionic gonadotropin (hCG) has been studied using hCG as an immunogen. Spleen cells of BALB/c mice immunized with hCG were fused with NS-1 mouse myeloma cells. This study reports the successful isolation of a hybrid clone secreting a monoclonal antibody specific for hCG. By using PEG 4,000 as a fusion agent, the fusion rates were between 42.0 and 50.2%. In total 842 hybridomas were produced. Among them, 403 hybridomas had hCG antibody production. After cloning twice by limiting dilution and alternately screening by enzyme immunoassay and by radioimmunoassay, there were 39 cell lines having specific antibody production. Among them, the No. 57-42-2 had the highest reactivity. By Ouchterlony test, the monoclonal antibody was shown to be IgG1. The affinity constant of the antibody to hCG was 0.6 x 10(9) 1/mole. In radioimmunoassay, the cross reactivity of the antibody to human luteinizing hormone (LH) and human follicle-stimulating hormone (FSH) was 1.5% and 0.7%, respectively. There was no cross reaction with human thyrotropin-stimulating hormone (TSH).

Animals↗
PubMed1986

Talon cusp in primary dentition.

Six cases of talon cusp in the primary dentition are reported, bringing to ten the total cases described in the literature. The dental anomaly affected only maxillary primary central incisors, and no succedaneous teeth were affected. None of the ten cases were associated with any abnormal development syndrome. Clinical observations suggest that the incidence of talon cusps in the primary dentition may be not lower than that in the permanent dentition in Chinese children.

Child↗
PubMed1985

Prevention of perinatal acquisition of hepatitis B virus carriage using vaccine: preliminary report of a randomized, double-blind placebo-controlled and comparative trial.

Hepatitis B is a serious disease of global significance. In developing countries, hepatitis B virus (HBV) infection and its sequelae rank among the public health problems of highest priority. Infants born to mothers who are chronic carriers of HBV are at particularly high risk of acquiring infection and becoming chronic HBV carriers. The efficacy of hepatitis B vaccine alone in preventing the transmission of HBV to infants born to HBV carrier mothers was determined in a double-blind placebo-controlled trial. Infants received plasma-derived vaccine at birth, 1 month, and 6 months of age. Of 180 infants born to hepatitis B surface antigen (HBsAg)-positive mothers, equal numbers received National Institute of Allergy and Infectious Disease (NIAID) vaccine, Beijing Institute of Vaccine and Serum (BIVS) vaccine, and placebo. The cumulative seroconversion to the vaccines at 1 year of age was 95% and 75%, respectively. Vaccine efficacy as measured by the prevention of HBsAg-positive events was 88% for the NIAID vaccine and 51% for the BIVS vaccine. Vaccine efficacy was similar among infants born to hepatitis Be antigen-positive mothers. Because of the low efficacy of the BIVS vaccine, an additional group of 28 infants was given vaccine and hepatitis B immune globulin at birth. The resulting efficacy was 83%. The results of this trial indicate that hepatitis B vaccine alone can substantially reduce perinatally acquired HBV infection and the resulting chronic carrier state.

Carrier State↗
PubMed1984

The secretion of human chorionic gonadotropin-like substance in women employing contraceptive measures.

To study the secretion pattern of a hCG-like substance (hCG') in normal women and those employing contraceptive measures, we assayed daily urine concentrates by RIAs using an anti-hCG beta-COOH-peptide serum and an anti-hCG serum to monitor hCG' and human LH (hLH), respectively. In eight cycles of four normal women, urinary hCG' was within the normal range (less than 100 ng/day), except that four samples in two women had marginal elevations of hCG' during the menstrual or premenstrual period, but not at the time of the midcycle hLH surge. Among seven cycles from three intrauterine device (IUD) users, six showed midcycle hLH surges, and in five, hCG' was prominent (0.17-3.6 micrograms/day) in the late luteal phase. In eight cycles of women ingesting steroid contraceptives on a conventional schedule, hCG' was found during the premenstrual and menstrual intervals. The pattern of hCG' secretion was episodic, and hCG' levels were in the range of 0.3-1.8 microgram/day. It was notable that hCG' was excreted at the highest levels during intervals when ingestion of steroids was withheld. These findings suggest that contraceptive steroid hormones may modulate pituitary hCG' secretion. From gel high pressure liquid chromatographic studies, the immunoactive hCG' detected in urinary extracts from normally cycling women and IUD users had a molecular size larger than hCG beta and hLH, but was slightly smaller than hCG (lot CR119). The hCG' identified in these eluents is unlikely to be a subunit of hCG. On the other hand, the immunoactive hCG' in the urinary extracts from oral contraceptive users was mainly the hCG beta-subunit-like substance. Both hCG alpha and hCG beta immunoactive substances were heterogeneous in size in contrast to those found in normally cycling women and IUD users. In summary, the hCG' excretion pattern was different in menstrual and postmenopausal women, and hCG' identified in these subjects was heterogeneous.

Adult↗