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Biomedical subjects

Z Tian

Publications and source records attributed to Z Tian.

88 records · Page 5Linked to original sources
PubMed1993

A sensitive enzyme immunoassay (EIA) for quantitation of the topical anti-inflammatory agent SCH 40120 in unextracted human plasma.

SCH 40120 is a potent acute anti-inflammatory agent under development for topical treatment of dermal inflammatory and allergic disorders such as atopic dermatitis, contact dermatitis and psoriasis. In order to support percutaneous absorption studies, a competitive enzyme immunoassay (EIA) was developed to determine SCH 40120 in unextracted plasma samples. SCH 38280, a carboxylated analogue of SCH 40120, was used as the hapten and conjugated with bovine thyroglobulin (Thy). The hapten-Thy conjugate was used as the immunogen to immunize rabbits for antibody production. The hapten was also coupled to horseradish peroxidase (HRP) to form SCH 38280-HRP, which was used as the tracer. The EIA can detect SCH 40120 concentrations as low as 50 pg ml-1 of plasma, and can reliably quantitate SCH 40120 in plasma samples from 100 pg ml-1 to 10 ng ml-1 with good linearity, accuracy and precision. A variety of structurally related compounds and potential metabolites did not significantly cross-react with the antibodies, except for a few analogues. The availability of this sensitive assay makes it possible to evaluate the pharmacokinetics of SCH 40120 in man.

Administration, Cutaneous↗
PubMed1993

Synthesis of phosphotyrosine-containing peptides by the solid-phase method. A re-examination of the use of Boc-Tyr(PO3Bzl2)-OH.

A practical and convenient procedure for making phosphotyrosine-containing peptides by the solid-phase method was developed. Phosphotyrosine was incorporated via Boc-Tyr(PO3Bzl2)-OH. The completed peptide was cleaved from the solid support by treatment with 1 M TMSBr-thioanisole-TFA. By gel-phase 31P-NMR spectroscopy we found that one of the benzyl protecting groups on phosphate was completely removed by two consecutive runs of Boc deprotection with 50% TFA-DCM. However, the other benzyl group remained intact throughout the synthesis (35 cycles).

Amino Acid Sequence↗
PubMed1993

[Clinical observation of the effect of pretreatment with nifedipine in preventing oxygen free radicals in the cardiopulmonary release bypass operation].

The effect of pretreatment with nifedipine in preventing oxygen free radicals release was observed in the cardiopulmonary bypass (CPB) operation. Twenty cases were divided into two groups for comparison. Nifedipine (0.6 mg/kg) was given to the test group. MDA, XO, UA and SOD were measured. These examinations were taken at pre-aortic clamping, 15 min after aortic clamping, and 30, 60, 120, 180 min after reperfusion. The results indicated that pretreatment with nifedipine reduced oxygen free radicals release in the CPB operation.

Adolescent↗
PubMed1992

The diagnostic significance of gastrin measurement of bronchoalveolar lavage fluid for lung cancer.

In this study, determination of gastrin concentration in bronchoalveolar lavage fluid and serum has been detected by radioimmunoassay in 30 cases of lung cancer and 24 cases of non-cancer pulmonary diseases. The results show that the gastrin concentration and its positive rate of lavage fluids from cancer lung are much higher than those from healthy lung and serum in lung cancer patients, and those from serum and both disease and healthy lung in non-cancer pulmonary disease patients (P less than 0.01). The gastrin ratio of lavage fluids from cancer lung to serum is also significantly higher than the ratio of lavage fluid from healthy lung to serum and all the ratios in the non-cancer pulmonary disease group. These results suggest that there is a high gastrin concentration in local tissue of lung cancer, which is signified by the high concentration of gastrin and its high positive rate in lavage fluids from the lung with cancer. Therefore, the gastrin determination in lavage fluids and gastrin ratio of lavage fluids to serum are more reliable in the differential diagnosis of benign from malignant pulmonary diseases than gastrin determination of serum alone.

Adenocarcinoma↗
PubMed1992

A competitive enzyme immunoassay for the direct determination of mometasone furoate (SCH 32088) in human plasma.

Mometasone furoate (SCH 32088) is a synthetic corticosteroid which has a topical anti-inflammatory activity with a minimal potential for suppressing hypothalamic-pituitary-adrenocortical (HPA) axis. A sensitive competitive enzyme immunoassay (EIA) for measuring SCH 32088 in unextracted human plasma has been developed. The 3-(O-carboxymethyl)oxime (CMO) of SCH 32088 was synthesized and conjugated with bovine thyroglobulin, and the product was used for the production of antibodies in rabbits. SCH 32088-3-CMO was also conjugated with horseradish peroxidase, which was used as the tracer. The EIA thus developed can detect 1 pg SCH 32088 per assay or 25 pg per ml of human plasma. It can reliably quantitate SCH 32088 in human plasma from 50 pg ml-1 to 2.5 ng ml-1 with good linearity, accuracy and precision. The assay can be extended to measure SCH 32088 in plasma of laboratory animals. The availability of this sensitive assay makes it possible to evaluate the pharmacokinetics and toxicokinetics of SCH 32088 in laboratory animals and man.

Administration, Topical↗
PubMed1992

Removal of Qa-2 antigen alters the Ped gene phenotype of preimplantation mouse embryos.

Embryo survival is influenced by both genetic and environmental factors. Previous research in our laboratory has identified one gene associated with embryonic survival, the Ped gene, a gene that is linked to the major histocompatibility complex (MHC) of the mouse. The Ped gene has been shown to influence the rate of preimplantation embryonic cleavage division, as well as litter size, birth weight, and weaning weight. Genetic mapping of the Ped gene has located it in the Q region of the MHC and has suggested that possible Q region genes encoding the Ped gene are Q3, Q5, Q6, Q7, Q8, and/or Q9. Whereas the protein products of the Q3 and Q5 genes are unknown, the protein product of the very similar Q6, Q7, Q8, and Q9 genes is the Qa-2 antigen. Two forms of membrane-bound Qa-2 antigen are known: glycosylphosphatidylinositol (GPI)-linked and transmembrane bound. Only the GPI-linked form is sensitive to cleavage by phosphatidylinositol phospholipase C (PI-PLC). The first purpose of the present study was to determine the nature of the linkage of the Qa-2 antigen to the cell surface of preimplantation mouse embryos. It was found that all detectable Qa-2 antigen on the embryonic cell surface is sensitive to cleavage by PI-PLC and is therefore bound to the cell membrane by a GPI linkage. Furthermore, removal of Qa-2 antigen from the embryonic cell surface slows down the rate of development of preimplantation mouse embryos. These results suggest the likelihood that the Qa-2 antigen is the Ped gene product.

Animals↗
PubMed1992

Synthesis of optically pure C alpha-methyl-arginine.

Optically pure L-(+)-C alpha-methyl-arginine and D-(-)-C alpha-methyl-arginine were synthesized. Experimental results indicated that DL-C alpha-methyl-arginine methyl ester could be resolved by trypsin, but workup posed a technical difficulty. Chemical resolution at the stage of DL-C alpha-methyl-ornithine, followed by selective guanidination using N,N'-di-Cbz-S-methylisothiourea and hydrogenolysis provided a effective and practical method for the synthesis of optically pure C alpha-methyl-arginine.

Arginine↗
PubMed1992

Surgical therapy of temporal lobe seizures.

Resection of epileptogenic lesions and pathological studies were performed in all 35 patients with temporal lobe epilepsy, 20 male and 15 female. Their ages ranged from 6 to 48 years with an average of 22 years. Various examinations including CT scan were carried out without any positive finding. EEG showed spike formation in the temporal lobes in all 35 patients. Epilepsy lesions were removed from the right temporal lobe in 22 patients and from the left temporal lobe in 13 patients. Pathological changes were found in all epilepsy lesions by light and electron microscopy. The operative outcomes were seizure-free since discharge in 10 patients (28.5%), seizure-free after some early attacks (34.2%) in 12 patients, seizure-free for 2 or more years and then rare or occasional attacks in 6 patients (17.1%), marked reduction of seizures in 5 patients (14.5%) and moderate or less reduction of seizure tendency in 2 patients (5.7%), with an effective rate of 93%. No death or severe complications did occur.

Adult↗
PubMed1991

[Consecutive observation of the plasma MDA, XO and UA levels and erythrocyte SOD in 10 cases of cardiopulmonary bypass].

The plasma malonaldehyde (MDA), xanthine oxidase (XO) and uric acid (UA) levels and erythrocyte superoxide dismutase (SOD) were measured in 10 cases during cardiopulmonary bypass (CPB) operation. These examinations were taken at pre-aortic clamping, 15 min after aortic clamping, 30, 60, 120 and 180 min after reperfusion respectively. The results showed that MDA, XO and UA rise but SOD decreases after reperfusion. We believe that a lot of oxygen free radicals (OFR) release during peri-operative period and the XO may be an important pathway of OFR release.

Cardiopulmonary Bypass↗
PubMed1990

[Application of ultrafiltration during cardiopulmonary bypass].

The ultrafiltration (UF) was employed in 20 patients undergoing open-heart operation with cardiopulmonary bypass (CPB). The number of controls was 10. The average UF duration was 24.7 +/- 9.6 min (12-49) and the average amount of ultrafiltrate was 1433.5 +/- 482.6 ml (650-2,350 ml). The volume load of UF group was similar with that of the control group. The output volume of UF group was greater than that of the control group (P less than 0.01). After UF, the degree of increase in hematocrit, plasma albumin and total plasma protein was 33.8%, 34.7%, and 26.0%, respectively. Moreover, we did not find any abnormal increase in blood viscosity. No additional adverse actions of UF were found.

Adolescent↗
PubMed1989

[Quality evaluation of twelve species of Chinese Ephedra (ma huang)].

The contents of six Ephedra alkaloids, namely ephedrine, pseudoephedrine, norephedrine, norpseudoephedrine, methylephedrine and methyl-pseudoephedrine, in 12 species of Chinese Ephedra collected in 24 districts were determined by high performance liquid chromatography (HPLC). Zorbax CN column (25 cm x 4.6 mm I.D.) was used and the temperature of column oven was 23-25 degrees C. Dibutylamine phosphate solution 0.0009 mol/L (pH 2.2) was used as the mobile phase at flow rates: 0.8 ml/min for the first 7 minutes, raised to 1.5 ml/min in 30 sec and maintained for 16 minutes. The alkaloids eluted were detected at wave-length 210 nm. The results showed that ephedrine and pseudoephedrine are the main components in these Ephedra herbs, but the contents of the six Ephedra alkaloids vary greatly with the plant species. The contents of total alkaloids are higher and ephedrine is the main component in samples derived from Ephedra sinica, E. equisetina, E. monosperma and E. intermedia var. tibetica; but in E. intermedia and E. lomatolepis, the content of pseudoephedrine is higher than that of ephedrine. Methylephedrine content is higher in E. intermedia var. tibetica produced in Xizang (Tibet) and in E. sinica produced in north-eastern China than that in other species. The results also showed that the samples derived from E. przewalskii and E. lepidosperma contain so little alkaloids (less than 0.1%) that they are considered not suitable to be used as the drug Ma Huang. It is of interest that the cultivated Ephedra sinica showed lower alkaloids content compared with that growing wild.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

In vitro and preclinical targeted alpha therapy for melanoma, breast, prostate and colorectal cancers.

Targeted alpha therapy (TAT) can inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The alpha emitting radioisotopes Tb-149 and Bi-213 were chelated to cancer specific monoclonal antibodies to form alpha-immunoconjugates (AIC) against melanoma, leukaemia, prostate and colorectal cancer, and to the plasminogen activator inhibitor type-2 (PAI2) to form alpha-PAI2 (API) against breast and prostate cancer. These conjugates were found to be highly stable, specific and cytotoxic in vitro. Melanoma and breast cancer tumour growth was observed in nude mouse models for untreated controls and non-specific AIC/API at 2 days post-subcutaneous inoculation of cancer cells. Complete inhibition of melanoma and breast cancer growth was found for local injections of AIC and API, respectively. Intra-lesional TAT of established melanoma showed that all melanomas regressed with 100 microCi injections of AIC. These results point to the potential application of local and systemic TAT in the management of metastatic cancer.

Alpha Particles↗
PubMedDate not supplied

Use of neuroendocrine hormones to promote reconstitution after bone marrow transplantation.

A survey of the previous literature and the data shown here indicate that neuroendocrine hormones such as growth hormone and prolactin may be of potential clinical use after bone marrow transplantation (BMT) to promote hematopoietic and immune recovery. The amounts of hormones used in our model do not promote weight gain suggesting that their lymphohematopoietic actions were independent of their anabolic effects. While the hormones may not produce the same extent of immune/hematopoietic effects when compared to conventional hematopoietic and immune stimulating cytokines (i.e. IL-2 or G-CSF), their pleiotropic effects and limited toxicity after systemic administration makes them attractive to test in the post-BMT setting. However, more work needs to be performed to understand the mechanism(s) of their action, particularly with regard to T-cell function and development.

Animals↗