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Biomedical subjects

C T Chu

Publications and source records attributed to C T Chu.

53 records · Page 3Linked to original sources
PubMed1990

Rapid and simple immunoassays for measurement of human chorionic gonadotropin using monoclonal antibodies.

Two monoclonal antibodies, designated Gab-35 and Gab-144, were used in competitive radioimmunoassay (RIA) and solid-phase sandwich enzyme immunoassay. By SDS-polyacrylamide gel electrophoresis and protein blot enzyme immunobinding assay, Gab-35 and Gab-144 were shown to react specifically to the alpha-subunit and beta-subunit of human chorionic gonadotropin (hCG), respectively. The immunoglobulin class and subclass of these two monoclonal antibodies were found to be IgG1 by the Ouchterlony double gel immunodiffusion test. The beta-subunit specific monoclonal antibody of Gab-144 was used in competitive RIA for determination of serum hCG in the range of 5-500 mIU/ml. The assay results correlated well with the monoclonal antibody-based RIA system and commercial RIA kits using polyclonal antisera. Moreover, the present competitive RIA system showed a shorter incubation time (1 hour 20 minutes) and a shorter total assay time (1 hour 40 minutes), as compared to those of the commercial RIA kit. A solid-phase sandwich enzyme immunoassay was developed using a combination of the Gab-35 antibody-coated microtiter plate and the beta-subunit specific antibody of Gab-144 conjugated with horseradish peroxidase (HRP). The assay range was 20-200 mIU/ml, and the incubation time was only 30 minutes. In addition, the solid-phase sandwich enzyme immunoassay developed in the present study could also be used as a qualitative hCG assay with a cutoff point of 50 mIU/ml as an early pregnancy test at or just a few days before the missed period.

Animals↗
PubMed1989

A human-human hybridoma which produces antibodies to polioviruses.

A human-human hybridoma which produced antibodies to Sabin strain poliovirus types 3 and 2 was established. This hybridoma was constructed by fusing a HAT-sensitive variant of a human lymphoblastoid subline R4-4-6 with peripheral blood lymphocytes of a donor who had been previously immunized with poliovirus Sabin vaccines and had shown high titer of neutralizing antibodies against these viruses. This hybridoma had been cultured for more than one year and the neutralizing activities of the culture supernatants against poliovirus type 3 could still be detected. Cross neutralization with poliovirus type 2 was also observed. Karyotypic analyses of this hybrid showed that the chromosome numbers were distributed mainly between 80 and 100. Dot immunobinding assays also confirmed the reactivities of this hybridoma supernatants with poliovirus type 3 and, slightly, with type 2.

Antibodies, Monoclonal↗
PubMed1988

Seroepidemiology of human T-cell lymphotropic virus type I infection in Taiwan.

The epidemiological characteristics of human T-cell lymphotropic virus type I infection in Taiwan have been explored by an island-wide community-based survey, which was carried out among residents in 19 townships and metropolitan precincts randomly selected through stratified sampling. Serum specimens of 7278 healthy subjects were screened by enzyme-linked immunosorbent assay and confirmed by Western blot method. A total of 103 subjects showed positive or weak reactions by enzyme-linked immunosorbent assay, but only 35 of them were confirmed to be positive by Western blot analysis. The anti-human T-cell lymphotropic virus type I antibody positive rate was 4.81/1000. The seropositive rate increased with age in both males and females, and females had a greater seropositive rate than males for all the age groups. Aborigines and Hakka Taiwanese had higher seropositive rates than Fukien Taiwanese and Mainland Chinese. Those people with lower educational levels were found to be associated with higher anti-human T-cell lymphotropic virus type I seropositive rates.

Adult↗
PubMed1988

Photoreactivities and thermal properties of psoralen cross-links.

We have studied the photoreaction of 8-methoxypsoralen (8-MOP), 4,5',8-trimethylpsoralen (TMP), and 4'-(hydroxymethyl)-4,5',8-trimethylpsoralen (HMT) with a pair of 18-base-long oligonucleotides in which a 14-base region is complementary. Only one 5'TpA site, favored for both monoadduct and cross-link formation with psoralen, is present in this oligonucleotide pair. We have used this model system to demonstrate, for the first time, strand specificity in the photoreaction of psoralen with DNA. We found that the two types of cross-links which form at this site have large differences in thermal stabilities. In addition, the denaturation of each cross-link isomer duplex occurred in at least three stages, which can be visualized as three bands in thermal equilibrium under the conditions of a denaturing polyacrylamide gel. This novel observation suggests that there are several domains differing in thermal stability in a psoralen cross-link.

Base Sequence↗
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↗
PubMed1987

Lysis of primary hepatic tumours by lymphokine activated killer cells.

Lymphokine activated killer cell is a newly described lytic system against a variety of solid tumours and is distinct in several respects from the classic cytolytic T cell and the natural killer systems. This study was conducted to evaluate the lytic activity of lymphokine activated killer cells against fresh autologous and allogeneic, as well as cultured hepatocellular carcinoma cells. Lymphokine activated killer cell was generated by incubating peripheral blood mononuclear cells with various concentrations of recombinant IL-2 (rIL-2, Cetus, USA) for various periods of time. A four hour 51Cr release assay was used to measure cytotoxicity. The results show that fresh and cultured hepatocellular carcinoma cells were only slightly susceptible to natural killer cells. Normal hepatocytes were resistant to lymphokine activated killer-mediated lysis. Lymphokine activated killer cells could be generated from mononuclear cells of hepatocellular carcinoma patients and normal subjects with lytic activity against fresh autologous and allogeneic and cultured hepatocellular carcinoma cells, but lymphokine activated killer cells from the former was less efficient than that from the latter. It is concluded that the adoptive immunotherapy with combined rIL-2 and lymphokine activated killer may be worth trying in early cases of primary hepatocellular carcinoma.

Adult↗
PubMed1987

Interleukin 2 and lymphokine-activated killer cells in the treatment of childhood primary hepatocellular carcinoma--a preliminary report.

Recombinant interleukin-2 (RIL-2) and lymphokine-activated killer (LAK) cells were administered to 2 boys with the end-stage of primary hepatocellular carcinoma (HCC); the efficacy and toxicity were evaluated. Immunologically, the natural killer and LAK activities were enhanced. Clinically, the side effects were similar to those reported for adults but milder. This kind of treatment may be considered for children with the early stages of hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1977

Possible role of infectious simian foamy virus DNA in persistent infection.

Simian foamy virus type 7 (SFV-7) can persist in peripheral blood leukocytes of SFV-7-infected rabbits. Rabbit peripheral blood leukoyctes cultured in vitro did not support the growth of SFV-7, but low titer of virus could be detected after 4 to 5 days incubation. The DNA derived from SFV-7 infected primary rabbit kidney cells is infectious. The presence of SFV-7 DNA provirus in infected rabbit kidney cells during replication may contribute one of the mechanisms of persistance.

Animals↗
PubMed1977

Infection of Taiwan monkey T and B cells with Epstein-Barr virus.

In order to establish Taiwan monkey lymphoblastoid cell lines, attempts were made to raise the susceptibility of monkey lymphocytes to Epstein-Barr virus (EBV) by chemical and enzymatic treatments. EBV infectivity to monkey T and B cells were tested by detection of EBV early antigens in infected cells with the indirect immunofluorescent antibody technique. Treatments of monkey unfractionated lymphocytes with DEAE-Dextran (160 microgram/ml) for 1 hr, ethylenediamine tetra-acetic acid (EDTA, 0.5%) for 10 min, 5-bromodeoxyuridine (BUdR, 12.5 microgram/ml) for 23 hr and 5-iodo-2'-deoxyuridine (IUdR, 12.5 microgram/ml) for 20 hr raised the susceptibility of the cells to EBV. However, trypsin treatment (0.05, 0.1 and 0.2%) at 37 degrees C for 5 min did not affect cell susceptibility to EBV. Unfractionated lymphocytes, T cells which were purified by rosette formation with sheep red blood cells, and a B cell-rich population obtained by the treatment of lymphocytes with antithymoycte serum were treated with the chemicals described above. The results showed that although the possibility of T cell susceptibility to EBV could not be ruled out because of 1 to 2.5% of B cell contamination in purified T cells, the main target cells in Taiwan monkey leukocytes for EBV infection were B cells.

Animals↗
PubMedDate not supplied

An analysis of sites of disease in revision endoscopic sinus surgery.

Revision endoscopic sinus surgery is performed when symptoms associated with sinusitis persist after sinus surgery and despite continued medical therapy. The causes of treatment failure are varied and may include systemic, mucosal, and anatomic factors associated with persistent inflammatory disease. The purpose of this retrospective review was to define the sites of recurrent or persistent sinonasal disease in patients undergoing revision endoscopic sinus surgery. This data was based on our preoperative CT scan and nasal endoscopy, as well as intraoperative findings. This study includes an evaluation of the most recent sinus surgery in a group of 153 patients and 265 operated sides. The frequency and distribution of regional anatomic sites of disease is presented and discussed.

Endoscopy↗
PubMedDate not supplied

Gliomatosis cerebri: cytologic and autopsy findings in a case involving the entire neuraxis.

We describe the case of a 7-year-old girl who was clinically diagnosed as having a pontine glioma based on magnetic resonance imaging studies. Neoplastic cells were identified upon cytologic examination of cerebrospinal fluid. Autopsy studies revealed an anaplastic astrocytoma (WHO grade III) diffusely infiltrating the cerebral hemispheres, brain stem, cerebellum, leptomeninges, and spinal cord to the level of the conus medullaris. The Ki-67 labeling index focally approached 30%. Although many of the neoplastic cells displayed elongated twisted nuclei reminiscent of microglia, these cells stained intensely for glial fibrillary acidic protein, supporting an astrocytic origin. Unusual features of this case of gliomatosis cerebri include involvement of the entire central neuraxis, correlation with pre-mortem lumbar puncture cytology, and a markedly elevated Ki-67 labeling index.

Astrocytoma↗