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Biomedical subjects

D X Wang

Publications and source records attributed to D X Wang.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Synthesis of small peptides containing hydroxy-amino-acid, and its effects on progesterone production].

Eleven peptides containing hydroxy-amino-acid have been synthesized manually by stepwise solid-phase method. Three of them were started on BHA-resin, the others on Merrifield-resin. TFMSA/TFA/p-cresol were used as cleaving reagent in all peptide-resin (1-11) cleavage. Furthermore, HF cleaving procedure was also used parallelly to five of those peptide-resins for contrast. No conspicuous difference in yield was found between TFMSA and HF. The purity of all products was checked by the profiles of analytical reversed phase HPLC (C-18) and the data of amino acid analysis. All synthetic peptides were tested for the effect on progesterone production by rat corpus luteum in vitro. Among them, three peptides, GlyTyr-NH2, LysTyr-NH2 and GlySer Lys-OH, showed significant effect (p less than 0.01) on inhibiting hCG-induced progesterone production.

Amino Acids↗
PubMed1990

Strain difference in pulmonary vascular responsiveness to hypoxia in rats.

The difference in pulmonary vascular response to hypoxia between Hilltop Sprague-Dawley (HT) rats and Wistar (W) rats was studied. Effects of inhibitor of leukotriene (LT) synthesis or prostaglandin (PG) synthesis on hypoxic pulmonary vasoconstriction (HPV) and chronic pulmonary hypertension were observed, and variations in plasma TXB2 and 6-keto-PGF1 alpha during hypoxia were determined. The results showed that in rats of both strains LTs are the major mediator of HPV, which is also mediated by vasoconstrictive PGs in HT rats, while modulated by vasodilative PGs in W rats. This might be the crucial mechanism responsible for the higher pulmonary vascular responsiveness in HT rats. Differences in the modulating effect of histamine and in the structural feature of pulmonary arteriole might be contributing factors as well.

Animals↗
PubMed1989

Sympathetic innervation of pulmonary circulation and its role in hypoxic pulmonary vasoconstriction.

The purposes of this study were to localize the position of spinal center of sympathetic nerve which controls the pulmonary circulation, and to evaluate the role of pulmonary sympathetic nerve in hypoxic pulmonary vasoconstriction (HPV) in pithed rat model. The sympathetic preganglionic fibers arising from C7-T10 segments were stimulated electrically in succession. During stimulation the pulmonary vascular resistance (PVR) was increased in all segments tested, most significantly in C7-T4 (about 28% above control value), obviously higher than that in T5-T10. The higher the stimulated spinal segments, the larger the ratio of delta PVR/ delta SVR. Alveolar hypoxia (12% O2-88% N2) could induce HPV in pithed rat. In the presence of hypoxia, stimulation of T1-T3 segments caused a double increment in PVR and Ppa as compared with those during normoxia (P less than 0.05). The data show that 1) the spinal center of sympathetic nerve regulating the vasomotion of pulmonary circulation is located in the C7-T4 segments; 2) the excitation of sympathetic nervous system during hypoxia could enhance HPV.

Animals↗
PubMed1989

Effects of cigarette smoking on hemodynamics and hypoxic pulmonary vasoconstriction: role of prostaglandins and leukotrienes.

This study investigated the role of prostaglandins (PGs) and leukotrieres (LTs) in hypoxic pulmonary vasoconstriction (HPV) and in cigarette smoking-induced changes in hemodynamics and HPV in Wistar rats. Selective LTD4-LTE4 receptor antagonist LY-171883 (LY) inhibited HPV by 71.8%, while cyclooxygenase inhibitor indomethacin (IND) augmented HPV. The results indicate that LTs mediate HPV in Wistar rats. Smoking increased the level of TXB2 over control by 143.6% in plasma and 69.2% in lung tissue, concomitantly, pulmonary and systemic vascular resistance (PVR and SVR) were increased by 38.7% and 46.7%, respectively. Both LY and IND prevented the smoking-induced increase of PVR and SVR. After smoking HPV increased twofold. The increase of HPV was abolished by LY, but not by IND. Our results suggest that smoking leads to pulmonary and systemic vasoconstriction partly mediated by TXA2 and LTs; smoking also leads to an augmentation of HPV, and LTs play an important role in it.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

[The role of lipoxygenase and cyclooxygenase metabolites in acute hypoxic pulmonary vasoconstriction in piglets].

The role of lipoxygenase and cyclooxygenase metabolites in acute hypoxic pulmonary vasoconstriction (HPV) was studied in piglets. It has been found that acute alveolar hypoxia induced remarkable pulmonary vasoconstriction, associated with an increase in cardiac output. The hypoxic pulmonary vasoconstriction response was insignificantly attenuated after infusion of DEC. Indomethacin potentiated markedly the increase in pulmonary artery pressure and pulmonary vascular resistance and thus augmented HPV. It is inferred that hypoxic pulmonary vasoconstriction in piglet may be mediated by other important mediators in addition to leukotrienes, but modulated by prostaglandins to prevent an excessive rise in pulmonary artery pressure.

Animals↗
PubMed1989

[A review of 152 cases of acute poisoning of hydrogen sulfide].

Clinical data of 152 cases of acute poisoning of hydrogen sulfide were analysed. Of these cases 5 were diagnosed as irritant reaction, 10 mild poisoning, 56 moderate, and 81 severe. Eight of the 152 cases died, with a fatality rate of 5.3%. 137 cases lost consciousness temporarily. The degree of disturbance of consciousness provided important basis for determining diagnostic grade. Recommendations for treatment were mainly comprehensive, supportive measures as well as first aid. Certain neuro-psychic sequelae were found in some of the 95 cases followed up for 1 to 10 years.

Adolescent↗
PubMed1985

Three cases of recurrent generalized muscle spasms in China.

Three cases of recurrent generalized muscle spasms were reported. All three cases are of Chinese descent and show some typical features of recurrent painful muscle cramps, alopecia, diarrhea and abnormalities of bone and endocrine systems. Recurrent generalized muscle spasms or Satoyoshi's disease is recognized as an entity of the disease not only in Japan but also in China. The result that one of the three cases is associated with myasthenia gravis might suggest an immunological abnormality as a mechanism of the disease.

Adolescent↗
PubMed1985

X-ray photoelectron spectra study on the derivatives of N-beta-phenethyl amine and N-beta-phenethyl glycine.

The X-ray photoelectron spectra of sixteen derivatives of N-beta-phenethyl amine and N-beta-phenethyl glycine have been studied. The effect of different structures on N1s binding energy and that of their Pauling's atomic charge density on the nitrogen atoms are investigated. The experimental binding energy of N1s is proportional to the calculated Pauling's atomic charge density. It shows that the phosphoryl group is the strongest nitrogen lone pair electron localizing group as compared with the corresponding sulfonyl and acyl derivatives. The XPS results agree with the data that there is no decarbonylation during the synthesis of N-dialkylphosphoryl-tetrahydro-3-benzazepin-1-one. In addition, since the N1s in P-N bond is smaller than that in S-N and C-N bonds, the phosphoryl group can be removed under much milder conditions. These results provide a semi-empirical evidence for the synthesis of the skeleton of the cephalotaxine. It also differentiates the reaction paths for these three different amino protecting groups.

Alkaloids↗