Biomedical subjects
Publications and source records attributed to X Fang.
In this paper the relationship of Tibetan Huanglian and Yunnan Huanglian with Coptis teeta has been studied. The distribution and taxonomic features of Tibetan Huanglian are just the same as Coptis teeta, but quite different from Yunnan Huanglian. The results reveal that Tibetan Huanglian and Yunnan Huanglian are different in botanical origin.
The rhizomes and roots of Curcuma are commonly used as Traditional Chinese Drugs. In this paper, a new species of Genus Curcuma from Sichuan, viz. Curcuma chuanyujin is reported, it is similar to C. aromatica, but differs from the dispersion of downs and the colour of bracts.
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Left ventricular end-systolic pressure-dimension relation (ESPDR) was generated by the transient occlusion of the inferior vena cava (IVC) or thoracic aorta (AO) in 13 anesthetized open-chest dogs, while the left ventricular pressure was measured by a TP-200T pressure transducer and the anterior-posterior dimension was measured by a pair of ultrasonic crystal implanted in the endocardium and recorded by a Sonomicrometer. The results showed that: (1) the ESPDR was shown to be linear, unaltered by preload or afterload changes; (2) dobutamine produced a significant increase in the slope (Emax) of the ESPDR-IVC and ESPDR-AO relations, without remarkable effect on the dimension-axis intercept (Do). However, the change in Emax was more significant for ESPDR-IVC (174.43 +/- 23.48%, n = 18), as compared with that for the ESPDR-AO (71.02 +/- 12.46%, n = 12); (3) Do of the ESPDR-AO relation was smaller than that of the ESPDR-IVC both under control and during dobulamine infusion. We conclude that the linear ESPDR can be derived in the anesthetized open-chest dogs either by caval occlusion or by aortic occlusion, and the slope appears to reflect left ventricular contractility. However, techniques used to generate the ESPDR may influence results, including the Do and the sensitivity of Emax to the inotropic state.
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The white blood cell (WBC) count and differential count, including the morphology and acid alpha-naphthyl acetate esterase (ANAE) activity of lymphocytes, in psoriatic patients of different types, stages, and extensiveness of skin lesions were analyzed. The number of total WBC and polymorphonuclear leukocytes was markedly increased in psoriasis erythrodermica and psoriasis pustulosa. Lymphocytopenia, especially T-lymphocytopenia, was noticed in all types of psoriasis. Antineoplastic drugs and immunosuppressants intensified the degree of T-lymphocytopenia. This might be the cause of recurrence and more recalcitrant course of the disease. Therefore, it is considered that these drugs should not be the first choice in the treatment of psoriasis.
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Elaeocarpus dolichostylus has afforded the new cucurbitacin derivative, hexanorcucurbitacin F (3), whose structure was determined by spectroscopic and chemical correlation with curcurbitacin F (1). Cucurbitacin F (1) and 23,24-dihydrocucurbitacin F (2) were also isolated in this study.
rac-2,3-Dimercaptosuccinic acid (rac-DMSA) may be a more effective antidote for the treatment of heavy metal poisoning than meso-2,3-dimercaptosuccinic acid (meso-DMSA), which is used at present. A comparative study of these two chelating agents has been undertaken in order to investigate this possibility. The structures of rac-DMSA and the precursor in its synthesis, rac-2,3-bis(acetylthio)succinic acid, have been determined by single-crystal X-ray analysis and compared with the structures of the corresponding meso compounds. The concentration distributions of the various ionic and molecular species of rac-DMSA that are present in aqueous solutions in the pH range 1.8-12.8 have been calculated from the four acid dissociation constants that have been determined potentiometrically at an ionic strength of 0.10. The conformations of these species in aqueous solutions have been determined by 1H NMR spectroscopy as a function of pH. The rac-DMSA exists in the crystal lattice as a double-stranded structure in which each molecule is in a gauche configuration. The meso-DMSA, however, exists in a single strand in which each molecule has adopted an anti configuration and the individual molecules are joined together at each end by hydrogen bonds. These differences in the conformations of rac- and meso-DMSA may account for the significant difference in the solubilities of the two compounds in aqueous solutions. In acidic solutions at elevated temperatures of about 95 degrees C, rac-DMSA is slowly but irreversibly converted to meso-DMSA. This conversion does not occur at ambient temperatures.
The conformations of meso-2,3-dimercaptosuccinic acid (meso-DMSA) in aqueous solution have been postulated from proton NMR titrations. The complexes formed with zinc(II) and the ligands rac-DMSA and meso-DMSA have been postulated from potentiometric titrations of solutions containing varying ratios of zinc:ligand. The complex formation behavior of rac-DMSA with zinc(II) is dramatically different from that of meso-DMSA. These differences are reflected in the complex formation constants of the zinc(II) species and their distributions in solution as a function of zinc:ligand ratios and as a function of pH. On the basis of these results we have predicted that rac-DMSA is more effective than meso-DMSA in mobilizing lead in vivo and that the 1:2 zinc complex of rac-DMSA can be used effectively for the treatment of heavy metal poisoning because endogenous zinc will not be depleted by this chelation treatment.
rac-2,3-Dimercaptosuccinic acid (DMSA) was found to be superior to meso-2,3-dimercaptosuccinc acid in mobilizing in vivo heavy metals such as Cd, Hg, and Pb. The disadvantage of using rac-DMSA alone as a clinical antidote for heavy metal poisoning is that it causes a greater loss of endogenous zinc than its meso isomer. The difference between the two diastereoisomers of DMSA in the excretion of endogenous zinc has been rationalized on the basis of the differences in the conformations of their zinc complexes. The zinc complexes of rac-DMSA in aqueous solution are more stable than the corresponding complexes of its meso isomer because the rac-DMSA ligands always adopt staggered anti conformations, in which the electrostatic repulsion between two bulky carboxylate groups is minimized; in contrast, unlike in the crystal lattice, meso-DMSA ligands always adopt staggered gauche conformations in their zinc complexes. The conformations of various monomeric and dimeric zinc complexes with rac- and meso-2,3-dimercaptosuccinic acid in aqueous solution were determined by IR spectroscopy and proton NMR spectroscopy as a function of zinc:ligand ratio, by proton NMR spectroscopy as a function of pD, and by variable-temperature 13C NMR spectroscopy. rac-DMSA in ZnL2(6-) coordinates with zinc ion via two thiolate groups and one carboxylate group, whereas in Zn2L2(4-) each ligand complexes two zinc ions by using one carboxylate group and one thiolate group in the beta-position to bind to the same zinc ion.(ABSTRACT TRUNCATED AT 250 WORDS)
The formation constants of various mercury and cadmium chelates of the stereoisomers of 2,3-dimercaptosuccinic acid (DMSA) have been determined from potentiometric titrations in the presence of the competing ligand EDTA. The mercury chelates formed at pH 7.4 are the monomeric HgL of the DMSA diastereoisomers and HHgL2 of rac-DMSA. Mercury is completely complexes at pH greater than 3.0 in solutions containing more than 1 equiv of either rac- or meso-DMSA. At high concentrations (10 microM and above) mercury tends to bind to a greater extent to rac- than to meso-DMSA. At pH 7.4, the predominant cadmium meso-DMSA chelate species in solution is CdL, and HCdL is present at a much smaller concentration. With rac-DMSA, however, the predominant cadmium chelate species is HCdL at a low concentration of the ligand, and at a high concentration of the ligand the species CdL2 predominates. Cadmium is completely chelated at pH 7.4 in solutions containing more than 1 equiv of either rac- or meso-DMSA. At pH around 5.5, which corresponds to the pH of the kidney, however, a significant amount of free cadmium is present in solutions containing 1 equiv or less of either DMSA stereoisomer. From the results of an analysis of speciation models, probable kidney damage, that may result from free cadmium ion release in the kidney during chelation therapy, is inferred when meso-DMSA is used for mobilizing cadmium. In contrast, the release of free cadmium ion is negligible in the pH range in the kidney when rac-DMSA is used. On the basis of the speciation models, rac-DMSA is found to be far superior to meso-DMSA in the treatment of acute cadmium poisoning.
Replication-competent adenoviruses (Ads) were used for oncolytic virotherapy soon after they were discovered. Recently mutated and genetically engineered Ads have been shown to selectively lyse tumor cells. We have split the human Ad type 5 genome into two defective viruses that complement each other only in certain tumor cells. The genome of one of these vectors, GT5610, contains only the minimal viral elements required in cis for replication and packaging and the E1 viral genes with E1A under the control of the human alpha-fetoprotein promoter. This "controlled" vector has a capacity for 30 kilobases of foreign DNA. The supplemental vector, AdHbeta, contains all adenoviral genes except for E1. Both vectors were designed to carry heterologous reporter genes whose expression could be detected throughout the tumor. Coinfection of hepatocarcinoma cells that have the capacity to transcribe genes under the control of the alpha-fetoprotein promoter leads to cell lysis and copropagation. The oncolytic spread of these complementary vectors in vivo was demonstrated by the intratumoral injection of human hepatocarcinomas xenografted in severe combined immunodeficient (SCID) mice. This system presents safety and gene capacity features that could yield a therapeutic advantage over oncolysis by a single virus.
OBJECTIVE: To determine the cytomorphologic features of bronchial tuberculosis on fiberoptic bronchoscopic brushings and its diagnostic value. STUDY DESIGN: Seven hundred forty-six bronchoscopic examinations were retrospectively studied. The patients' macroscopic findings made by fiberoptic bronchoscopic examination, as well as brush cytologic and biopsy findings, were reviewed. RESULTS: Of 746 bronchoscopic brushing specimens, 23 were diagnosed as endobronchial tuberculosis by cytomorphology; that accounted for about 3.1% of cases. The same or a similar diagnosis was made for both specimen types in 16 of the specimen pairs. Acid-fast stain showed that only one brushing was positive (4.3%); all the biopsy specimens were negative. Epithelioid cell granulomas and/or caseous necrosis were found in 23 cases of brush smears, while tuberculous granulomas accounted for 16 bronchial biopsies. Seven were nonspecific chronic bronchitis or normal bronchial mucosa. CONCLUSION: The cytomorphologic alterations of tuberculosis are suitable for diagnosing bronchial tuberculosis on fiberoptic bronchoscopic brushings. Its sensitivity for defining bronchial tuberculosis is not lower than that of bronchial histologic biopsies or bacteriologic examination.