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Biomedical subjects

X B Wang

Publications and source records attributed to X B Wang.

87 records · Page 5Linked to original sources
PubMed1989

Lidocaine inhibits dispersed anterior pituitary cell thyrotropin and prolactin secretion induced by thyrotropin-releasing hormone or high medium potassium.

Lidocaine at a concentration greater than or equal to 0.1 mM inhibited thyrotropin (TSH) and prolactin (PRL) secretion by perifused acutely dispersed rat adenohypophyseal cells stimulated by 10-100 microM thyrotropin-releasing hormone (TRH) or 30 mM K+. The concentration of lidocaine required for half-maximal inhibition of TSH and PRL secretion was approximately 1 and 0.5 mM, respectively. Maximal lidocaine inhibition of TRH-induced secretion was induced within 15 min and a normal response to these secretagogues returned within 20 min after removal of lidocaine from the perifusion medium. The inhibition of secretion by lidocaine may be caused by blocking depolarization of the cell membrane and depressing intracellular calcium mobilization and calcium influx across the plasma membrane.

Animals↗
PubMed1989

[Studies on saponins from the leaves of Panax japonicus var. bipinnatifidus(Seem.)Wu et Feng].

Two new saponins, bipinnatifidusoside F1(XII) and F2(XIII), were isolated along with eleven known saponins from the dried leaves of Panax japonicus var.bipinnatifidus(Seem.)Wu et Feng collected in the Range of Qinling Mountains in China. By spectrometric analysis(FAB-MS,1H and 13CNMR,1H-1H COSY), their structures were elucidated as dammar-25(26)-ene-3 beta, 12 beta, 20(S),24 zeta-tetraol-(20-O-beta-D-glucopyranosyl)-3-O- beta-D-glucopyranosyl(1-2)-beta-D-glucopyranoside (bipinnatifidusodie F1) and dammar-22(23) ene-3 beta, 12 beta, 20(S),24 zeta-tetraol-(20-O-beta-D-glucopyranosyl)-3-O-beta- D-glucopyranosyl(1-2)-beta-D-glucopyranoside (bipinnatifidusoside F2), respectively. The known saponins were identified as ginsenoside F1,F2,F3,Rg2,Re,Rd,Rb1,Rb3, 24(S)-pseudoginsenoside F11, panasenoside and majoroside F1. Compared with bipinnatifidusoside F2, majoroside F3 was corrected as dammar-22(23)-ene-3 beta, 12 beta,20(S),24 zeta-tetraol-(20-O-beta-D- glucopyranosyl)-3-O-beta-D-glucopyranoside.

Chemical Phenomena↗
PubMed1989

[Further study on dammarane saponins of leaves of Panax japonicus var. major collected in Quinling Mountains China].

In continuation of our studies on the leaves of Panax japonicus var. major (Burk.) Wu et Feng, two new dammarane saponins are isolated. By means of FAB-MS and 13CNMR, their structures were elucidated as dammar-22(23)-ene-3 beta, 6 alpha, 12 beta, 20(S), 24 section-pentaol- (20-O-beta-D-glucopyranosyl)-6-O-alpha-L-rhamnopyranosyl (1-2)-beta-D- glucopyranoside (majorosids F5) and dammar-23(24)-ene-3 beta, 6 alpha, 12 beta, 20(S), 25-pentaol-(20-O-beta-D- glucopyranosyl)-6-O-alpha-L-rhamnopyranosyl(1-2)-beta-D-glucopyranoside (majoroside F6).

Chemical Phenomena↗
PubMed1989

[Hypercalcemia and hyperphosphatemia in thyrotoxoicosis and the therapeutic effect of propranolol].

Measured levels of serum calcium, phosphate, alkaline phosphatase, and urinary hydroxyproline were measured and calcium-phosphate product was calculated in 20 hyperthyroid patients and 20 normal controls. Eleven of the patients took propranolol 160 mg per day for 28 days. We found that the serum level of calcium was higher than that of normal controls. The incidence of hypercalcaemia in hyperthyroid patients was 10%. The serum level of phosphate and the calcium-phosphate product increased (P less than 0.01). Elevation of alkaline phosphatase and bone alkaline phosphatase were also observed (P less than 0.01). The urinary hydroxyproline was also elevated (P less than 0.01). After treatment with propranolol serum calcium and triiodothyronine decreased (P less than 0.05). It is suggested that the major mechanism of hypercalcaemia and hyperphosphatemia in hyperthyroidism was increase of bone absorption stimulated by triiodothyronine. Propranolol decreased the serum level of calcium through decreasing triiodothyronine level and through beta-receptor blocking effect as well as its direct effect on bone.

Adolescent↗
PubMed1987

Clinical evaluation of the 99mTc-labeled myocardial imaging agent, hexakis (t-butylisonitrile)-technetium.

99mTc-TBI myocardial perfusion imaging has been studied in 7 normal subjects and 24 patients with coronary artery disease. Scintigraphic data revealed that 99mTc-TBI myocardial perfusion imaging is more sensitive than ECG in detecting myocardial infarction. In comparing 99mTc-TBI imaging with contrast angiography, its' sensitivity for the diagnosis of coronary artery disease was 91.7%.

Adult↗
PubMed1985

Human apolipoprotein B: identification of cDNA clones and characterization of mRNA.

Apolipoprotein B (apoB) is a major protein component of low density and very low density lipoproteins. Because of its large size and heterogeneity, molecular studies of apoB have been difficult, and its structure and regulation remain poorly understood. We now report the identification of human apoB cDNA clones by antibody screening of hepatoma libraries in the expression vector lambda gt11. Both oligo(dT) primed and random primed libraries were constructed and screened with polyclonal antibodies to intact apoB, as well as with antibodies raised against a synthetic peptide based on the limited amino acid sequence available for apoB. The identity of the clones was unambiguously established by comparisons of the cloned cDNA sequences with apoB amino acid sequences. The clones hybridize to an exceptionally large 20 kb mRNA that is present in liver and intestine but not other tissues examined, consistent with the distribution expected from protein biosynthetic studies. The properties of the mRNA have implications for the biogenesis of the multiple apoB molecular weight forms secreted by liver and intestine.

Apolipoproteins B↗
PubMedDate not supplied

Apolipoprotein B: the Ag(a1/d) immunogenetic polymorphism coincides with a T-to-C substitution at nucleotide 1981, creating an Alu I restriction site.

Short cDNA fragments covering the entire coding region for apolipoprotein (apo) B have been cloned in the pING expression vector. A monoclonal antibody specific for the Ag(d) epitope on apo B has been used, together with the expressed apo B peptides, to locate this epitope to a stretch of 26 amino acids. Sequencing of this region from several genomic DNAs of known Ag(a1/d) genotype showed a single T-to-C substitution at nucleotide 1981, creating an Alu I restriction site and resulting in a val to ala residue change in the corresponding peptide (at position 591 in the mature protein). Southern blots, using the Alu I restriction endonuclease and a short probe for this region of the cDNA, showed perfect correspondence between the restriction fragment length polymorphism and the Ag(a1/d) immunochemical polymorphism in all 17 persons examined.

Apolipoproteins B↗
PubMedDate not supplied

Bsp 12861 restriction fragment length polymorphism detects Ag(c/g) locus of human apolipoprotein B in all 17 persons studied.

Southern blot analysis of the genomic DNA from 17 individuals showed perfect correspondence between a Bsp 12861 restriction fragment length polymorphism (RFLP) and the Ag(c/g) locus on human apolipoprotein (apo) B. The RFLP polymorphism is caused by a C--------T transition at nucleotide 421 on the cDNA, resulting in a threonine-to-isoleucine conversion. Thus, three of the five Ag sites have now been tentatively located on the 4536 residue apo B peptide at amino acyl residues 71: Ag(c/g), 591 (Ag(a1/d), and 4154 Ag(t/z).

Apolipoproteins B↗