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Biomedical subjects

Y Guo

Publications and source records attributed to Y Guo.

At least 613 records · Page 34Linked to original sources
PubMed1992

[Characterization of monoclonal antibody (BIU-H) directed against bladder cancer and its pathologic feature].

The characteristics of one of a group of monoclonal antibodies named BIU-H6 are reported. Using McAb BIU-H6, by ABC-immunohistochemical staining directed against 34 bladder cancers and 5 normal bladders. It was found that BIU-H6 does not react with normal bladder epithelial and adenocarcinoma of the bladder, but with transitional cell carcinoma, squamous cell carcinoma and CIS of the bladder. The staining characters were variant according to the different grade/stage of the cancer. The result shows that BIU-H6 antigen is a tumor associated antigen of poorly differentiated and invasive carcinoma of the bladder.

Animals↗
PubMed1992

[Production of prostacyclin in human umbilical cord blood vessels. Effect of natural and synthetic estrogen].

This investigation was conducted to evaluate the effects of 17 beta-estradiol and 17 alpha-ethinylestradiol on prostacyclin PGI2-production in homogenates of human umbilical cord arteries and veins in the presence of exogenous arachidonic acid. The incubation of 17 beta-estradiol at 2 different concentrations (10(-8) and 10(-6) M) in the presence of arachidonic acid for various times (5 min up to 24 h) effected an increase in the production of PGI2 (measured as 6-keto-prostaglandin F1 alpha) of 36-47% in the artery and 16-21% in the vein over basal values (100%). Under the same experimental conditions with 17 alpha-ethinylestradiol we observed an increases of 30-40% in the artery and 1-18% in the vein compared with basal values. For both estrogens this was not significantly different compared with untreated samples. In our in vitro system, natural and synthetic estrogens had no clear effect on PGI2 production in homogenates of human umbilical vessels.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Production of the glycosylphosphatidylinositol-specific phospholipase D by the islets of Langerhans.

A large number of diverse cell surface proteins are anchored to the cell membrane by a glycosylphosphatidylinositol (GPI) anchor. One proposed function for the GPI anchor is that it facilitates the release of the protein from the cell by acting as a target for anchor-specific phospholipases. We and others have discovered that mammalian plasma contains a GPI-specific phospholipase D (GPI-PLD) (Cardoso de Almeida, M. L., Turner, M. J., Stambuk, B. V., and Schenkman, S. (1988) Biochem, Biophys. Res. Commun. 150, 476-482; Davitz, M. A., Hereld, D., Shak, S., Krakow, J., Englund, P. T., and Nussenzweig, V. (1987) Science 238, 81-84; Low, M. G., and Prasad, A. R. S. (1988) Proc. Natl. Acad. Sci. U. S. A. 85, 980-984). Because the GPI-PLD recognizes a conserved portion of the anchor, all GPI-anchored proteins are potential substrates for the enzyme. We demonstrate in this communication the production of the plasma GPI-PLD by the islets of Langerhans. GPI-PLD enzymatic activity was found in dog pancreatic microsomes, but not pancreatic juice. Both the pancreatic and plasma enzymes were divalent cation-dependent and had identical substrate specificities. Purified murine islets of Langerhans, as well as alpha and beta cells, contained and released GPI-PLD activity. A GPI-PLD DNA fragment was amplified by polymerase chain reaction from a normal human islet cDNA library; the amplified fragment hybridized with the GPI-PLD cDNA clone. These findings represent the first demonstration of the production of the plasma GPI-PLD by a specific tissue site as well as cell type.

Animals↗
PubMed1991

Site-specific mutagenesis of human follistatin.

Follistatin is a monomeric protein originally discovered in ovarian follicular fluid as a suppressor of pituitary follicle-stimulating hormone (FSH) secretion, and later identified as a binding protein for activin. To explore the role of the Asn-linked carbohydrate chains on the follistatin molecule in regard to the inhibition of FSH secretion and activin binding ability, site-specific mutations were introduced at either or both of the two potential Asn-linked glycosylation sites of human follistatin with 315 amino acids (hFS-315). The three types of follistatin mutants were expressed individually in Chinese hamster ovary cells. When tested for their ability to inhibit FSH secretion and to bind activin, each mutant was found to have a similar property as the non-mutated recombinant hFS-315, suggesting that glycosylation of the follistatin molecule has no effect in these functions. However, a two amino acid insertion in between the second and the third amino acid residues in hFS-315 caused the resulting compound to lose completely its inhibitory activity on FSH secretion from the pituitary as well as its binding ability to activin. This finding suggests that the amino-terminal region of the follistatin molecule is critical for both of these functions.

Activins↗
PubMed1991

Detection of cannabinoid receptors by photoaffinity labelling.

A novel [125I]-labelled photoaffinity ligand designed to detect cannabinoid binding sites has been used in mouse brain preparations and in cultured S49 mouse lymphoma cells. The ligand, 2-iodo-5'-azido-delta 8-THC, shows a high affinity for sites in both brain (Kd = 5.60 pM) and whole cell (Kd = 9.38 pM) systems. Photolabelling studies with brain samples revealed the existence of four ligand-protein adducts, of estimated molecular weights 85.5, 62.1, 30.0 and 25.5 kDa, that were diminished by prior exposure to 8 microM THC. A similar study with S49 cells gave adducts with apparent molecular weights of 62.1, 34.4, 16.9 and 13.5 kDa. The ligand produces a typical cannabinoid cataleptic response in mice suggesting that possibly one or more of the binding sites may be involved in some of the receptor mediated actions of THC.

Affinity Labels↗
PubMed1991

A case of basophilic leukemia bearing simultaneous translocations t(8;21) and t(9;22).

We report a case of basophilic leukemia with simultaneous translocations of t(8;21) and t(9;22). The patient's clinical and hematologic findings were characteristic only of t(9;22) but not of t(8;21). This unusual cytogenetic phenomenon raises a challenge to the current concepts of primary chromosomal abnormalities in cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Effect of acetylpolyamines on in vitro protein synthesis and on the growth of a polyamine-requiring mutant of Escherichia coli.

The functions of acetylpolyamines were examined with respect to stimulation of protein synthesis and cell growth. Unlike polyamines, acetylpolyamines could not lower the optimal Mg2+ concentration of protein synthesis, and the degree of stimulation of protein synthesis by acetylpolyamines was small. The addition of N1-acetylspermine did not stimulate cell growth of a polyamine-requiring mutant of Escherichia coli MA261, although acetylspermine was accumulated in the cells. Acetylspermine did not interfere with polyamine stimulation of protein synthesis and cell growth of E. coli MA261. The binding of acetylpolyamines to RNA was very weak, and the binding of polyamines to RNA was not disturbed significantly by the presence of acetylpolyamines. When the growth of E. coli MA261 was stimulated by addition of polyamines, significant amounts of acetylpolyamines were also formed in the cells. These results suggest that acetylation of polyamines, together with polyamine excretion, may regulate the intracellular level of the parent polyamines when excess amounts of polyamines accumulate intracellularly.

Acetylation↗
PubMed1991

Recombinant expression of human follistatin with 315 and 288 amino acids: chemical and biological comparison with native porcine follistatin.

Follistatin is a glycosylated monomeric protein originally isolated from ovarian follicular fluid based on its ability to specifically inhibit pituitary FSH release. To further explore the physiological role of follistatin, we have expressed recombinant human follistatins with 315 (rhFS-315) and 288 (rhFS-288) amino acids in Chinese hamster ovary cells under the control of the simian virus-40 promoter. The two types of FS originated from alternatively spliced mRNAs and rhFS-315 differed from rhFS-288 by having an extra 27-amino acid sequence at the carboxyl-terminal. The yield of the purified rhFS-315 and rhFS-288 after a single step of affinity chromatography on an activin-coupled Affi-Gel column was 3-5 mg/liter conditioned medium. Using the rhFS-315 and rhFS-288 as molecular mass markers, Western blotting with FS carboxyl-terminal-specific antibodies demonstrated that the majority of native FS isolated from porcine ovarian follicular fluid was neither FS-315 nor FS-288, but was composed of 300 amino acids in various forms of glycosylation. This finding is consistent with our earlier results obtained from tryptic peptide fragment analysis of native FS. Only a very small percentage (less than 1%) of native porcine FS was FS-288. In cultures of rat anterior pituitary cells, rhFS-315 (ED50, 115.2 +/- 16.2 pM) is equipotent to native porcine FS (ED50, 86.7 +/- 14.1 pM) on the suppression of FSH release, but, surprisingly, rhFS-288 (ED50, 9.6 +/- 2.2 pM) is 8-10 times more potent than the native protein, similar to the potency of inhibin-A (ED50, 8.6 +/- 0.9 pM). Interestingly, when the in vivo FSH-suppressing activity of rhFS-288 was compared to that of inhibin-A in 1-week ovariectomized adult rats, it was found that rhFS-288 was more potent and longer acting than inhibin-A. Hence, these results indicate that FS-288 is probably one of the most potent natural FSH suppressors.

Amino Acid Sequence↗
PubMed1991

[Type distribution of human papilloma virus (HPV) in cervical cancer].

For analysis of the relationship between HPV type and the progress of cervical cancer, we investigated the distribution of HPV genome type in 171 cases of papilloma, cervical neoplasm early cancer and invasive cancer. The results showed that Chinese Human Papilloma Virus type 16 (CHPV16) and Chinese Human Papilloma Virus non-classified type 1 (CHPVX1) have positive rates 11.5%, 4.8%, 50.0% and 48.8%, respectively. While HPV11/HPV6 decreased with developing of cervical neoplasia. Their positive rate was 76.9%, 26.8%, 10.0% and 2.4%, respectively. There was significant difference (P less than 0.01) in X2 test for trend. It was indicated that there is a strong correlation between the CHPV16/CHPVX1 and the developing of cervical cancer.

Aged↗
PubMed1991

Molecular and morphologic changes during the epithelial-mesenchymal transformation of palatal shelf medial edge epithelium in vitro.

The fate of the medial edge epithelial (MEE) cells during palatal fusion has been proposed to be either programmed cell death or epithelial-mesenchymal transformation. Vital cell labeling techniques were used to mark the MEE and observe their fate during palatal fusion in vitro. Fetal mouse palatal shelves were labeled with Dil and allowed to proceed through fusion while maintained in an organ culture system. The tissues were examined at several stages of palatal fusion for the distribution of Dil, presence of specific antigens and ultrastructural appearance of the cells. The MEE labeled with Dil occupied a midline position at all stages of palatal fusion. Initially the cells had keratin intermediate filaments and were separated from the underlying mesenchyme by an intact basement membrane. During the process of fusion the basement membrane was degraded and the Dil-labeled MEE were in contact with the mesenchymal-derived extracellular matrix. In the late stages of fusion the Dil-labeled MEE altered their cellular morphology, had vimentin intermediate filaments, and were not associated with an identifiable basement membrane. Dil-labeled cells, without an epithelial phenotype, remained present in the midline of the completely fused palate. The data indicate that the MEE did not die but underwent a phenotypic transformation to viable mesenchymal cell types, which were retained in the palatal mesenchyme.

Animals↗
PubMed1991

Establishment of human myeloma cell line KM-2R and its preliminary application to human-human hybridoma research.

The authors report the establishment of a human myeloma cell line--KM-2R--and its preliminary use in human-human hybridoma research. KM-2R cells are resistant to both 6-TG and ouabain. Their doubling time is about 30 h. They have a modal chromosome number of 81-85. Using ELISA and immunodiffusion techniques, gamma-heavy and kappa-light chains were detected in the concentrated cell culture supernatant. KM-2R cells are sensitive to HAT medium. When fusing with normal human spleen cells, tonsil cells, and B lymphoblasts transformed by EB virus, fusion frequencies of 20-60% resulted.

Cell Division↗
PubMed1991

[The clinical significance of repetitive ventricular response induced by programmed electrical stimulation].

To clarify clinical significance of repetitive ventricular response (RVR), 50 patients with different kinds of heart disease were given ventricular programmed electrical stimulation. The results showed that: (1) The incidence of RVR is independent of heart disease, and it is as high as 83.87% even in the patients without organic heart disease; (2) There is no correlation between RVR and spontaneous ventricular tachycardias; (3) There may be some predictive value to the induction of monomorphic sustained ventricular tachycardias when RVR greater than or equal to 3 QRS complexes.

Adolescent↗
PubMed1991

[The study on calcium ion concentration specificity in meridian and acupoint in rabbit].

Ion selected "Acupuncture electrode" was introduced for detection of calcium ion concentration in meridians and acupoints in rabbit. It was demonstrated that the calcium ion concentration was significant higher than that in the location of non-meridian and non-acupoint. This is the first and important finding of physicochemical characteristics of meridians.

Acupuncture Points↗