Biomedical subjects
Publications and source records attributed to F Liu.
Eight constituents were isolated from the ether solvent fraction of leaves of Apocynum venetum and identified as triacontanol, beta-sitosterol, quercetin, hyperin, long-chain fatty acids (C28-C34), lupeol, scopoletin and isofraxidin. Isofraxidin and hyperin were effective sedative components.
A study was made on the effects of Epimedium sagittatum polysaccharides on DNA synthesis of bone marrow cells of "yang deficiency" animal model caused by hydroxyurea with methods of cell culture in vitro and determination of 3H-TdR incorporating DNA of bone marrow cells. The results showed that after the treatment with 100 micrograms of Epimedium sagittatum polysaccharides, the cell multiplication rate was increased by 72% and DNA synthesis rate increased by 68%, in 1 x 10(6) cells.
Safflower yellow (SY) extracted from Carthamus tinctorius L contained chalconoid compounds, 75% of which was safflomin A. SY ip 50-450 mg.kg-1.d-1 x 6-8 d in mice decreased serum lysozyme concentration and phagocytosing functions of both peritoneal macrophages and peripheral leukocytes; diminished the production of plaque forming cells, specific rosette forming cells, and antibody; inhibited delayed type hypersensitivity reaction and the activation of T suppressor cells elicited by supraoptimal immunization. Experiments in vitro showed inhibitory effects on [3H]TdR incorporation during human peripheral T- and B-lymphocyte proliferation by SY 0.03-3.0, 0.1-2.0 mg.ml-1 respectively, murine mixed lymphocyte culture response and the production of interleukin-2 by SY 0.1-2.5 mg.ml-1. In conclusion, SY produced declines in both nonspecific and specific immune functions.
The rates of Sister Chromatid Exchange (SCE) were scored in short-term cultivated peripheral lymphocytes taken from 49 SLE patients and 22 of their first degree relatives. Higher SCEs were found in these two groups as compared with the normal controls. The patients' serum levels of Superoxide Dismutase (SOD) were lower while those of their relatives were normal. Addition of SOD was able to induce marked SCE decrease. Our results indicate that SLE is associated with primary DNA repair defect and that the reduction of SOD might play an important role in the development of SLE. and exogenic SOD has certain protective effect on the human body.
A project to compare different levels of a hydatid disease control program was instigated and evaluated in 16 randomly selected villages in the Xinjiang/Uygur Autonomous Region, PRC (China). Factors tested included the effect of: 1) the role of a village hydatid disease control officer, 2) the use of praziquantel-medicated "bait" tablets for treatment of Echinococcus granulosus tapeworms in dogs, and 3) the use of educational materials for children and adults. Evaluation of contrasting treatment levels was done by determining infection rates of E. granulosus in about 25 dogs examined from each of the 16 villages before and after the trial period, and by use of pre- and post-treatment questionnaires distributed to 40 randomly selected households in each village. Optimum results were obtained in those villages which received medicated tablets and support visits from a control officer on a monthly basis (so-called "moderate intervention level").
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The adenovirus E1a protein stimulates transcription of viral early genes. Recent experiments indicate that E1a contains a transcriptional activating region, which functions when directed to a promoter. Because E1a is not a sequence-specific DNA binding protein, how it targets to viral promoters has been a question. Several of the viral early promoters contain one or more binding sites for ATFs, a family of cellular transcription factors. Here we show that E1a can function through a specific ATF protein, designated ATF-2. We provide evidence that E1a interacts with a discrete region of promoter-bound ATF-2, thereby positioning the E1a activating region at a viral promoter.
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The interaction of Mg2+, AMP, and fructose 2,6-bisphosphate with respect to rabbit liver fructose-1,6-bisphosphatase was investigated by studying initial-rate kinetics of the system at pH 9.5. A rapid-equilibrium Random Bi Bi mechanism is suggested for the rabbit liver enzyme from the kinetic data. Our kinetic findings indicate that Mg2+ and the inhibitor AMP are mutually exclusive in their binding to fructose-1,6-bisphosphatase. This probably is the mechanism for AMP regulation of fructose-1,6-bisphosphatase and thus, to some extent, gluconeogenesis. A kinetic model for the interaction of these ligands with respect to rabbit liver fructose-1,6-bisphosphatase is presented.
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Reaction of Escherichia coli adenylosuccinate synthetase with the thiol reagent 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) or N-ethylmaleimide (NEM) leads to modification of one cysteine residue per enzyme monomer without significant loss of enzyme activity. Modification of a second cysteine residue occurs under mild denaturing conditions (3.5 M urea), and derivatization of this thiol followed by dialysis results in complete loss of enzyme activity. The remaining two cysteine residues react with DTNB only after treatment with 8 M urea. The location of the various cysteine residues in the enzyme was established by using [14C]NEM followed by tryptic digestion and radiopeptide isolation. The reactive cysteine has been identified as Cys291, and the thiol exposed with 3.5 M urea is Cys344. When Cys344 was replaced by either serine or alanine, the mutant enzymes were found to be as active as the wild-type enzyme. These findings point to the nonessential role of Cys344 in adenylosuccinate synthetase.
Western ligand blotting of human serum reveals proteins of 41.5, 38, 33, 28, and 23 kD which will specifically bind [125I]insulin-like growth factor-I [( 125I]IGF-I). The relationship of these binding proteins (BPs) to the two serum BP-IGF complexes of 150 and 40 kD and their relationship to the two purified and well characterized IGF-BPs, BP-25 and BP-53, are not clear. The studies reported here used gel filtration, Western ligand blotting, deglycosylation, affinity cross-linking, and immunoprecipitation with antisera against BP-25 and BP-53 to explore the relationship among these IGF-BP forms. Serum from children with chronic renal failure was used for this study, since, by Western ligand blot, it was rich in all five IGF-BPs. The 28- and 33-kD BPs, which were hard to detect in normal serum, were elevated in chronic renal failure serum. Using this serum in each experiment, it was found that the large (150-kD) BP-IGF complex contained only the 41.5- and 38-kD BPs. Both of these BPs were precipitated by anti-BP-53 antiserum, but not by anti-BP-25 antisera, and both BPs were deglycosylated by endoglycosidase-F to a single 31-kD protein which retained the ability to bind IGF-I. This molecular mass of 31 kD is similar to the 28.7-kD mass for nonglycosylated BP-53 predicted by cDNA sequence analysis. In contrast, the 33-, 28-, and 23-kD BPs were only detected in the small (40-kD) BP-IGF complex. None of the three BPs was precipitated by anti-BP-53 antiserum, and none was digested by endoglycosidase-F. The 28-kD BP comigrated with pure BP-25 under all conditions and was precipitated by two independent anti-BP-25 antisera. The 33-kD BP was also precipitated by both anti-BP-25 antisera, while the 23-kD BP was not precipitated by any of the antisera tested. Thus, BP-53 consists of a core protein of 28.7 kD which is differentially glycosylated in serum to form two BPs of 41.5 and 38 kD; these BPs circulate exclusively as part of the large BP-IGF complex. BP-25 circulates in the small BP-IGF complex as a nonglycosylated protein with an apparent mol wt of 28 kD.(ABSTRACT TRUNCATED AT 400 WORDS)
Angiographic features of the pulmonary artery were studied in 24 patients with aortoarteritis (Takayasu's arteritis) by digital subtraction angiography. The pulmonary artery involvement was found in nine cases (37.5%). The right side was involved in eight and the left side in five cases. The right pulmonary artery was involved in two cases, the lobar artery in six, the segmental artery in six, and subsegmental as well as peripheral branches in four. The angiographic features were stenosis and/or occlusion as were the changes of the systemic arteries in aorto-arteritis. The aorta and its main branches were involved in all nine patients, but the severity of pulmonary vascular changes was not always related to the systemic vascular changes. Bronchial angiography demonstrated enlarged and tortuous bronchial arteries in four cases. Lung ECT revealed abnormalities in four cases.
Anti-inflammatory effects of calcium antagonists verapamil (Ver), nifedipine (Nif) and nicardipine (Nic) were compared. They all produced significant inhibitions in acute and chronic inflammatory models in a dose-dependent manner. The ED30 in the capillary permeability were: Ver 18, Nif 12 and Nic 8 mg/kg, respectively. In the xylene-induced swelling of mouse ears, the ED30 were: Ver 39, Nif 14, and Nic 25 mg/kg, respectively. In the carrageenan paw edema of mice, and in the acetic acid-induced pleurisy and cotton granuloma of rats these drugs inhibited inflammatory responses at 5 or 10 mg/kg. Nif showed a greater effect than Ver and Nic on the paw edema, and Ver showed greater effects than NIf and Nic on the pleurisy and granuloma. At 10 mg/kg they depressed the PGE2 content measured by radioimmunoassay in inflammatory tissues of carrageenan paw edema of mice.