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Biomedical subjects

L L Yu

Publications and source records attributed to L L Yu.

25 records · Page 2Linked to original sources
PubMed1994

Analysis of human growth hormone gene 5' sequences in isolated growth hormone deficiency patients.

Human growth hormone (hGH) gene deletion (6.7 to 7.6 kb) is one of the causes of isolated growth hormone deficiency (IGHD), named IGHD IA. IGHD IA, however, only accounts for about 10% of the total IGHD patients. Most IGHD is caused by unknown mechanisms. Here, hGH gene 5' sequences in three IGHD patients without hGH gene deletion were analysed to see if there was any mutation hindering the expression of the hGH gene.

Base Sequence↗
PubMed1993

Optimal conditions of chemotherapeutic sensitivity in K562 cell line using tetrazolium dye assay.

Ten antineoplastic agents were used on K562 cell lines with the tetrazolium salts (MTT) assay to investigate optimal conditions of the chemotherapeutic sensitivity. The doubling time of K562 cell was 20.4 h in 96-well microtitre plates. The optical density in MTT assay of the no-drug controls was 0.77 (n = 45). A 70% reduction (IC70) in absorbance compared with control values using an ELISA reader at 570 nm was referred to as drug sensitive and < 70% (IC70) was referred to as resistant. The inhibitory effect of the theoretical maximal plasma drug concentration (Cmax) in plasma was compared with that of 10% Cmax drug concentration. At 10% Cmax after a 2-d drug exposure to daunorubicin and homoharringtonine, or after 5 d to epirubicin, 5-fluorouracil, cytarabine hydrochloride, and doxorubicin, significant cytotoxicities were shown. There were little time-dependent effects after 2-5 d drug exposure for 4 out of the 10 tested drugs, and mild or marked time- and dose-dependent effect for others.

Antineoplastic Agents↗
PubMed1993

A stable vector for high-level expression and secretion of human interferon alpha A in yeast.

Yeast high stable plasmid vector pHC11 was constructed by introducing pEM-BL Yi27 cleaved with SmaI into the SnaBI site of intact 2 microns plasmid. The result of plasmid stability assay revealed that 82% of the host cells still harbored the vector after 50-generations growth in non-selective medium, which confirmed the existence of a non-functional region in 2 microns plasmid. The human interferon alpha A (IFN alpha A) gene expression-secretion cassette was inserted into pHC11, and the yeast transformant was cultured in complex medium. The data showed that the expressed product was 36.8% of the total protein amount in the culture supernatant and the IFN alpha A biological activity was 2.6 x 10(10) units per liter, demonstrating that high-level expression and secretion of IFN alpha A were achieved in yeast by using the stable vector pHC11.

Escherichia coli↗
PubMed1985

Attenuation of tracheal smooth muscle contraction by connective tissue.

Removing the fibroelastic connective tissue, which surrounds the smooth muscle of the pig trachea, enhanced contractions and decreased desensitization in vitro in response to histamine. There were no differences between the preparations in the presence of indomethacin. The magnitude of contraction to acetylcholine was not significantly different. Incubation of the connective tissue in histamine solution caused the appearance of a substance(s) which relaxed other, precontracted tracheal muscles. Propranolol did not block this relaxation. Intact connective tissue appears to reduce the reactivity of the tracheal smooth muscle to histamine.

Acetylcholine↗