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Y Q Lu

Publications and source records attributed to Y Q Lu.

At least 37 records · Page 2Linked to original sources
PubMed1995

Effects of toquipidine on ionic channels of cultured embryonic Xenopus laevis myoblasts and neurons.

AIM: To study the effects of toquipidine (1-p-methyl-phenyl-2-(alpha-piperidinoacetyl)-1, 2, 3, 4-tetrahydroisoquinoline hydrochloride, Toq), a new anti-arrhythmic agent first synthesized in China, on ionic channels. METHODS: Ionic channel currents were recorded by whole-cell patch clamp technique in cultured embryonic Xenopus laevis myoblasts and neurons. RESULTS: Toq (0.1, 1, 10, and 100 mumol L-1) caused a concentration-dependent inhibition of the Na+ currents with IC50 7.2 mumol L-1 (5.3-9.8 mumol L-1). Toq (10 mumol L-1) also suppressed the high-voltage-activated Ca2+ currents in neurons. But the steady-state outward K+ currents in myoblasts were activated by Toq (10 mumol L-1). CONCLUSION: Toq blocked the Na+ and Ca2+ channels and opened the steady-state outward K+ channels.

Animals↗
PubMed1994

[Molecular degradation forms of plasma fibronectin in patients with chronic obstructive pulmonary disease].

In order to explore the molecular degradation forms of plasma fibronectin (Fn) in patients with chronic obstructive pulmonary disease (COPD) and its clinical value. We measured the concentration of plasma Fn and analysed Fn molecular forms. The results suggested that the increase of Fn degradation is one of the causes of plasma Fn decline in patients with COPD. The obvious correlations were found between the extent of Fn degradation and the severity of the disease. In view of the documented influences of Fn fragments on the host defense, the increase of Fn fragments in plasma of COPD patients may be an additional factor of inflammatory amplification loops and more contributing to the decrease of plasma opsonic activity.

Aged↗
PubMed1994

Identification of beta-adrenoceptors in mouse myometrium by radioligand binding study.

The binding of radioligand to cell membrane prepared from mouse myometrium was used to identify the characteristics of beta-adrenoceptors. Uteri were taken from mature mice (Kunming Strain) weighing 40 +/- 5 g pretreated with estradiol benzoate 1 mg.kg-1.d-1 ip for 2 d. The binding of [3H]dihydroalprenolol ([3H]DHA) to uterine membrane was saturable, having a Bmax of 378 fmol/mg protein and a KD of 3.1 nmol.L-1. The slope of Hill plot (nH = 1.03) indicated the absence of cooperative interactions. IC50 and K1 values of l-norepinephrine (NE), dl-propranol (Pro), d-timolol (d-Tim), and l-Tim competed for the [3H]DHA binding sites were 171 +/- 10, 10.3 +/- 4.3, 6.5 +/- 2.1, 0.40 +/- 0.23 nmol.L-1 and 113 +/- 6, 6.3 +/- 2.8, 4.0 +/- 1.3, 0.25 +/- 0.14 nmol.L-1, respectively. These 4 agents competed for the [3H]DHA binding sites in an order of potency: l-Tim > d-Tim > Pro > NE. Atenolol (Ate) did not compete for [3H]DHA binding sites. The results suggested that these binding sites for [3H]DHA in mouse myometrium appeared to be beta 2-adrenoceptor.

Animals↗
PubMed1993

Involvement of membrane glycophorins in human erythrocytes invaded by Plasmodium falciparum.

The extent of participation and changes of glycophorins (GPs) and membrane proteins in the merozite-human erythrocyte interaction during the invasion of Plasmodium falciparum (Pf) were studied by immunoblotting techniques. Polyclonal antisera to alpha GP and to its C-terminal fragment (residues 82-131) as well as M and N specific monoclonal antibodies (MoAbs) were used. We examined the GPs in the parasite-free saponin lysates, saponin pellets and the culture supernatants of the infected erythrocytes in comparison with the mock cultured normal RBC. Excepting the usual GP patterns, a GP with molecular weight of 77.5 K (band 1') existed in the parasitized erythrocytes and their saponin pellets and several GP bands ranging from 28K to 54K were present in saponin pellets when probed with anti-GP and anti-peptide C sera. This reflected the disintegration of erythrocyte membrane alpha GP through the invasion of Pf. The alpha 2 GP in the saponin pellets of the parasitized MM erythrocytes surprisingly cross-reacted with the N MoAb, implying that it may have come from the intermingling of the host alpha GP in MM erythrocytes with the parasite alpha GP reacting to N MoAb. The saponin pellets of parasitized erythrocytes preserved a considerable amount of ankyrin, band 3, protein 4.1 and 4.2, while the GP bands were densely mixed with the parasite proteins and the disintegrated products of membrane proteins. Four erythrocyte-binding antigens (EBA) of 143 K, 135 K, 115 K and 107 K recognized by malaria hyperimmune serum were detected in the culture supernatants of Pf, some of them appeared in the infected erythrocytes, their saponin lysates and pellets.

Animals↗
PubMed1992

Elliptocytosis associated with an abnormal alpha glycophorin.

A case of elliptocytosis associated with an undescribed abnormal alpha glycophorin (alpha GP) is reported. Using immunoblotting techniques, a clear-cut minor band 6' was detected emerging just behind the monomer of delta GP (band 6) when probed with anti-alpha GP antiserum. It also reacted with anti-peptide C antiserum, suggesting that this new band with a molecular weight of 24 K is related to the structural alteration of alpha GP and not delta GP. The erythrocyte membrane proteins of the patient exhibited a quite normal pattern, with a normal alpha spectrin/beta spectrin ratio, but the reaction with anti-protein 4.1 serum confirmed the increase in proteolytic susceptibility of her protein 4.1. The results of DNA mapping implied that the abnormality may be due to a short deletion of the heterozygote. The significance of deviation involving the alpha GP and protein 4.1 to the elliptocytic change of erythrocyte shape is briefly discussed.

Aged↗
PubMed1991

[Effect of (-)-stepholidine on blood pressure and alpha-adrenoceptor agonists-, KCl- and CaCl2-evoked contractions of aortic strips].

Iv (-)-SPD lowered the blood pressure in anesthetized rat, the ED50 value was 5.1 +/- 2.5 mg.kg-1. In the experiments of rat and rabbit aortic strips, (-)-SPD 0.3-100.0 mumol.L-1 inhibited the contraction initiated by clonidine (alpha 2) and phenylephrine (alpha 1) and shifted the dose-response curve to the right parallely without change in maximum response. The inhibitory ratio of (-)-SPD acting on alpha 2/alpha 1 adrenergic receptors was about 7.2, and (-)-SPD thus was predominant inhibition on alpha 2 adrenergic receptors. In the experiment of aortic strips from reserpinized rabbits, the inhibition of (-)-SPD on contraction evoked by clonidine was diminished markedly. The results suggest that (-)-SPD stimulated mainly the alpha 2-adrenergic receptors of presynaptic nerve endings. Moreover (-)-SPD 1 mumol.L-1 inhibited the release of intracellular Ca2+ initiated by NE. (-)-SPD 3-30 mumol.L-1 blocked the voltage-dependent Ca2+ channel.

Animals↗
PubMed1991

Antagonistic effects of dihydropyridines and verapamil on CaCl2 and 5-HT-evoked contraction in porcine coronary artery.

In porcine coronary arterial strips, the antagonistic effects of nifedipine (Nif), nimodipine (Nim), nicardipine (Nic), felodipine (Fel), and verapamil (Ver) to CaCl2-evoked contraction in Ca(2+)-free, K(+)-depolarized solution were greater than that to 5-HT. The order of potency (pD2') was Nif (9.1) greater than Fel (8.4) greater than Nim (7.9) greater than Nic (7.8) greater than Ver (7.2) to CaCl2 and Nif (8.3) greater than Nim (7.5) greater than Fel (6.8) greater than Ver (5.6) greater than Nic (5.3) to 5-HT. Ver inhibited 2 components of 5-HT-evoked contraction in Ca(2+)-free solution, but Fel inhibited only extracellular Ca(2+)-dependent contraction, suggesting that their action modes are different.

Animals↗
PubMed1991

[A screening survey of variant glycophorins on the erythrocyte membranes among healthy chinese young people].

A screening survey of variant glycophorins (GP) on the erythrocyte membranes was conducted among 114 healthy Chinese young people who belong to several different ethnic groups by immunoblotting techniques. The majority (70) were of the Han ethnic group; 24 out of 41 Hainanese belonged to the Li ethnic group. Ten subjects showed variant GP profiles, with an incidence of 8.8%. The frequency of variants was significantly higher in the Li ethnic group (25%) than in the Han ethnic group (5.7%); none was seen among the other ethnic minorities. Probing with four antibodies specific to different regions of GP molecules revealed three distinct types of GP among the variant individuals. Type I observed in four individuals was reminiscent of that exhibited by Sta glycophorin. Among them, in one subject the Sta blood group phenotype was confirmed by serological typing. The absence of delta GP was noted in another subject carrying type II variant GP. Patterns in the remaining five individuals (type III) could not be correlated with known GP profiles of variants of MNSs blood system. This study suggests that there may be a high incidence of GP variants among certain ethnic groups in China. The sialic acid contents of erythrocyte membranes in seven GP propositi were significantly higher than those of the control.

Adolescent↗
PubMed1990

Studies on function of Hb Jianghua [beta 120 (GH3) Lys----Ile].

Hemoglobin Jianghua (Hb Jianghua) is a new fast--moving hemoglobin variant found in China, being named after the county where it was detected. Having its primary structure analysed, we report in this paper the results of studies on its function. The absorption spectrum, response to allosteric effectors and oxygen equilibrium of the chromatographically purified Hb Jianghua showed its characteristics similar to those of purified Hb A. Its alkaline Bohr effect was normal. This indicates that a substitution of isoleucine for the 120th lysine residue of the beta chain had no significant influence upon the function of Hb molecule.

China↗
PubMed1989

[Autoradiographic study on etorphine and phencyclidine specific binding sites in rabbit mesenteric artery].

Autoradiography was used to study the localization of kappa and PCP/sigma receptors in the blood vessels. Slices of rabbit mesenteric arteries were incubated with 0.4 nmol/L [3H]etorphine or/and 10 mumol/L etorphine for 45 min at 25 degrees C, or incubated with 5.2 nmol/L [3H]PCP or/and 20 mumol/L PCP for 60 min at 4 degrees C. Then, slices were covered with emulsion coated coverslip and kept for 8-10 wk at 4 degrees C. The results were as follows: Microscopy Autoradiographic analysis indicated that etorphine and PCP specific binding sites were both located in the outer-layer and the smooth muscle of the artery. However, most of these binding sites were lost in the 6-OHDA pretreated arteries in which the adrenergic nerve endings were destroyed. Microspectrophotometry The absorbance (A) of [3H]etorphine autoradiographic density for total binding (TB) and nonspecific binding (NSB) in control group were 0.416 +/- 0.056 and 0.044 +/- 0.011, respectively (P less than 0.01), and for TB after incubation with 6-OHDA was 0.068 +/- 0.013 which was different from the A value of TB in the control (P less than 0.01). The A value of [3H]PCP autoradiographic density for TB and NSB in the control were 0.546 +/- 0.087 and 0.023 +/- 0.060, respectively (P less than 0.01), and for TB after incubation with 6-OHDA was 0.065 +/- 0.015 which was significantly less than that of TB in the control group (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Polymorphism of glycophorins in nonhuman primate erythrocytes.

Using immunoblotting techniques and polyclonal antisera to human erythrocyte alpha glycophorin, we show that erythrocytes of several species of nonhuman primates, including representatives of anthropoid apes (19 chimpanzees, 3 gorillas, 6 orangutans, and 3 gibbons) and Old World monkeys (3 baboons, 5 rhesus monkeys, and 6 cynomolgus macaques), contain human alpha glycophorin-like molecules. Each species displays a unique glycophorin profile; in anthropoid apes the profile is more complex than in Old World monkeys and more similar to that seen in humans. The chimpanzee was the only species in which human delta-like glycophorin was detected but it differed from its human counterpart in electrophoretic mobility and reaction with M-specific monoclonal antibody. In contrast to humans, highly polymorphic glycophorin profiles were observed in each species of anthropoid apes and three distinct patterns were defined in each. No such polymorphism has been found so far among the Old World monkeys in the limited number of animals studied. The major glycophorins in all species but the chimpanzees failed to react with M- or N-specific monoclonal antibodies, suggesting structural differences from the human within the amino terminal regions. The reaction with the minor glycophorins showed inter- and intraspecies variability. All glycophorins, except delta-like glycophorin in the chimpanzee, reacted with the antiserum to the carboxyl terminal fragment of human alpha glycophorin, indicating a structural relation to the human in this region. An unexpected correlation was observed, in the chimpanzee, between the patterns of electrophoretically resolved glycophorins and the V-A-B-D blood-group phenotypes, allowing the assignment of each determinant to specific glycophorin bands. The basis for the differences observed between human and nonhuman primate glycophorins is not clear but the possibilities include a common nonpolymorphic ancestor and differences in selective pressures.

Animals↗
PubMed1987

Structural polymorphism of glycophorins demonstrated by immunoblotting techniques.

We have explored the polymorphism of the glycophorin system in the human erythrocyte membrane using the immunoblotting techniques and examining 52 individuals selected without prior bias as to their serologic state and ten documented serologic variants of M, N, S, s blood group system. Polyclonal antisera to alpha glycophorin and to alpha glycophorin CNBr carboxyl terminal fragment C (residues 82-131) and M and N specific monoclonal antibodies (MoAbs) were used. The first two reagents detect specific regions of the alpha glycophorin molecule and all electrophoretically resolved species of glycophorins immunologically related to alpha and delta glycophorins (delta glycophorin, [alpha-delta] hybrids and other glycophorins with an alteration in the carboxyl terminal segment); the M and N MoAbs identified the glycophorin species containing or lacking the M or N determinant in the amino terminal octapeptide structures. We find that immunoblotting confirmed in all cases the serologically determined phenotype; we also find that polymorphic forms of the glycophorin system are relatively infrequent; immunoblotting, independent from serologic testing, was capable of detecting five mutants, two most likely S-s-U-phenotypes; a new glycophorin species was detected in normal red cells with both antiglycophorin and antipeptide C sera, which is not evident with MoAbs; immunoblots of known glycophorin variants (En(a-), U-, Mg, Mi I, II, III, V, and Sta) confirmed but also extended our knowledge of the abnormal glycophorins involved; and the He+ and Wrb(-) cells showed normal patterns.

Glycophorins↗