Biomedical subjects

T Lan

Publications and source records attributed to T Lan.

26 records · Page 2Linked to original sources

PubMed1992

[Studies on human chorionic gonadotropin (HCG)-binding protein from Pseudomonas maltophilia by ligand blotting assay].

A ligand blotting technique was developed to study the HCG-binding protein from Pseudomonas maltophilia after size separation by SDS-polyacrylamide gel electrophoresis under nonreducing conditions. The separated proteins were transferred to a nitrocellulose sheet, which was subsequently incubated with [125I]iodo HCG, and subjected to determination for radioactivity in gamma-counter. A radioactivity peak equivalent to an M(r) 70000 appeared, which was not observed when the hormone incubation was performed in the presence of an excess of unlabeled HCG. The peak also disappeared when the protein samples were treated with reducing agent, which showed that integrity disulfide bonds of the protein was essential for the protein-hormone interaction. In addition, position of the radioactivity peak which was due to the binding of [125I]iodo HCG to western blots of the HCG-binding protein was corresponding to that of the antibodies against the HCG-binding protein recognizing a 70000 protein on the western blots. These results show that the HCG-binding protein from Pseudomonas maltophilia is an M(r) 70000 protein and that the HCG-binding protein contains at least one disulfide bond essential to its binding activity.

Blotting, Western↗

PubMed1991

[Study of VLDL- and HDL-receptor on isolated parenchymal and non-parenchymal cells from rat liver].

Saturable high-affinity VLDL and HDL receptor on parenchymal cells (PC), and non-parenchymal cells (NPC) freshly isolated from rat liver were studied. The VLDL- and HDL-receptor could mediate liver PC and NPC to bind, uptake, and degrade 125I-labeled human VLDL and apoE-deficient HDL3, and the activities of these two receptors (expressed as ng/mg cell protein) on NPC were about 10- and 4-fold higher than those on PC, respectively. VLDL receptor on NPC with kd 15.0-34.2 micrograms/ml and Bmax 2170-2607 ng/mg cell protein could be inhibited by EDTA, and down-regulated by cell cholesterol content. HDL receptor on NPC with kd 10.1-17.7 micrograms/ml and Bmax 1004-2738 ng/mg cell protein could not be inhibited by EDTA, but could be up-regulated by cell cholesterol content. Competitive inhibition assay showed that VLDL receptor could not only bind VLDL and LDL, but also bind HDL3 to some extent. Unlabeled purified apolipoprotein CIII-1, but apoAI, CI, CII, could effectively inhibit 125I-labeled VLDL binding to NPC. These results suggest that liver NPC may be more active than PC in clearing VLDL and HDL from circulation, and apolipoprotein CIII play an important inhibitory role in these receptor-mediated processes.

Animals↗

PubMed1991

[A study on characters of liver isoferritin].

The characters of liver isoferritin from Wistar rat, normal human and patient with hepatocellular carcinoma (HCC) were studied. The ratio of iron to protein of liver isoferritin from patient with HCC were 0.021, which accounts for about one-twelfth of that of liver isoferritin from normal human. The molecular weights of liver isoferritin from normal human and the patient with HCC were 20.5 kd and 21.5 kd, respectively. The electrophoresis patterns of liver isoferritin from both Wistar rat and patient with HCC showed one band, but two bands from normal human. There was cross reaction in immunity among isoferritins from normal human liver, Wistar rat liver and horse spleen by double immunodiffusion. The PAGE patterns of liver isoferritin from different sources could be clearly differentiated. The data presented may serve as a good reference for further study of the relationship between the structure and function of ferritin and may be used practically in clinical medicine.

Animals↗

PubMed1991

[The distribution of apolipoproteins AI, CII and CIII mRNA in rat tissues].

It was demonstrated that apo AI, CII and CIII mRNA were distributed in rat (Sprague Dawley) liver, intestine, brain and kidney by RNA-dot blot analysis with apoAI, CII and CIII cDNA probes. The relative abundances of apoAI in liver, intestine, brain and kidney tissues are 100%, 212%, 170% and 224%, respectively, those of apoCII are 100%, 61%, 163% and 214%; and those of apoCIII 100%, 65%, 70% and 73%, respectively. The experiment was repeated for three times. The results were discussed in this paper.

Adult↗

PubMed1991

[Research and application of SUPER-1 intellectural instrument used in physiology laboratory].

Research work for making a biomedical signal processing instrument based on the APPLE-II computer is reported in this paper. According to the theory of the computer, two interface boards were designed as the hardware of the instrument. The memorizing waveform program was designed as the main program in the software system. Through a functional extended program, also called software inter face, more than ten programs especially for physiology can be easily linked to the main program. with the combination of both the software and hard ware several parameters of the instrument, such as sampling speed, gain of the amplifier, etc. can be controlled by a closed loop. This instrument is available in the physiology laboratory to replace oscilloscope, recorder, stimulator simultaneously. The functions of the instrument are stronger than those of the conventional instruments.

Microcomputers↗

PubMed1991

[Influences of new synthetic drug vesnarinone on circulatory and respiratory function of dogs].

The purpose of this study was to investigate the influences of vesnarinone, newly synthesized in the School of Pharmacy, West China University of Medical Sciences in 1985, on the circulatory and respiratory functions of dogs. Eight dogs were anesthetized with 3% sodium pentobarbital. Vesnarinone (2 mg/kg), dimethyl sulphoxide (the solvent which was needed to prepare solution of OPC-8212), and 0.9% NaCl (normal control) was given separately according to the arrangement of Latin square. The ECG, blood flow, blood pressure and respiration were measured and recorded for 1-15 minutes. Vesnarinone increased the blood flow in the common carotid artery with no significant changes in blood pressure, heart rate, or respiration. These results suggest that OPC-8212 has positive inotropic effect but no effect on the heart rate in anesthetized dogs.

Animals↗

PubMed1990

[Screening and identification of apolipoprotein CIII cDNA clones from human liver cDNA library and preparation of apolipoprotein CIII cDNA probe from the clones].

Four of positive clones were obtained by three runs of screening the cDNA library of human liver with rabbit antihuman apolipoprotein (apo) CIII IgG. One of them was identified to be the positive clone of apoC III cDNA by restriction endonuclease map studies of the cDNA insert fragment and by Western blot analysis of the expression products. The apoCIII cDNA-gamma gt11 recombinant DNA prepared from the positive clone can be used in RNA-dot blot analysis as apoCIII cDNA probe. And the apoCIII cDNA clone can be also used to produced apoCIII peptide under the induction of isopropyl-beta-D-thiogalactoside. The apoCIII peptide, after purification, has a lot of use in further studies.

Apolipoprotein C-III↗

PubMed1990

[Effect of a new positive inotropic agent (OPC-8212) on intracellular potential of isolated canine ventricular papillary muscle].

This study adopted intracellular microelectrode technic to observe the effect of OPC-8212 (Vesnarinone) on intracellular potential of isolated canine ventricular papillary muscle. The record and data processing were completed by computerized intellective instrument designed by ourselves. The results of intracellular record in 14 canine ventricular papillary muscle showed no significant change in the resting potential (RP), amplitude of action potential (APA) and maximum depolarize velocity of 0 phase (Vmax). But significantly increased whole duration of action potential (APT). The duration of repolarization to 1/3 (APD 1/3) and to 2/3 (APD 2/3) significantly increased too. The plateau phase raised. These results suggest that K+ permeability at resting myocardiac cell membrane may have not been effected by OPC-8212. Activation of the fast sodium channel may have not been effected too. The results of our studies also suggest that inward flow of Ca2+ increased. The delayed outward K+ (Ik) and the inward, rectifying K+ current (Ik1) possible decreased. Thus, the OPC-8212 might become a nonglucoside and noncatecholamine new positive inotropic drug.

Action Potentials↗