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Biomedical subjects

F Liu

Publications and source records attributed to F Liu.

At least 703 records · Page 39Linked to original sources
PubMed1990

Application of traditional Chinese drugs in comprehensive treatment of primary liver cancer.

The present paper is a summary for treating 50 cases of Stage II primary liver cancer by the Integrated method of traditional Chinese and Western medicine. It was found by comparative observation that the average survival time of the Spleen-Deficiency (SD) type patients was markedly longer than that of Phlegm-Dampness-Stagnancy (PDS), Qi- and Blood-Stagnancy (QBS) and Liver-Kidney-Yin-Deficiency (LKYD) types, indicating that the SD type patients might have a better prognosis, and that the Chinese herbal medicine was an alternative for treating intermediate and late carcinoma.

Carcinoma, Hepatocellular↗
PubMed1990

[Influence of nicardipine on the morphology, calcium and cAMP level of immune organs in mice].

Nicardipine, 10 mg/kg sc qd x 4d, caused morphological changes of immune organs in mice. The germinal centers of lymph nodes markedly reduced. The white pulps of spleens and the cortex of thymuses atrophied slightly. In these lymphoid tissues, the small lymphocytes markedly increased and the heterochromatin of nuclei increased. In the subcellular level, nicardipine damaged the structure of mitochondria in various cells. The lymphocytes in peripheral blood and the calcium content and cAMP level in immune organs markedly decreased. These results suggest that nicardipine inhibited proliferation of lymphocytes in vivo, and this effect was probably associated with the decreasing calcium content in immune organs. Influence on the structure and functions of mitochondria may be one of the mechanisms of nicardipine inhibiting functions of immune cells.

Animals↗
PubMed1990

[Chemical constituents of the seed oil of Astragalus complanatus R. Brown].

beta-sitosterol and fatty acids were obtained from the oil of seeds of Astragalus complanatus. The fatty acids were separated and their molecular weights determined by GC-MS. Fourteen of them were identified as heptenoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, octadecenoic acid, octadecanoic acid, octadecadienoic acid, linolenic acid, eicosanoic acid, eicosenoic acid and docosanoic acid, etc.

Drugs, Chinese Herbal↗
PubMed1990

Cystic echinococcosis in the Xinjiang/Uygur Autonomous Region, People's Republic of China. I. Demographic and epidemiologic data.

Demographic and epidemiologic data on those factors potentially related to the prevalence and transmission of hydatid disease caused by Echinococcus granulosus were collected in 1987 from each household in 85 villages in the two communities of Yuanhucun and Ershilidian within Hutubi County in the Xinjiang/Uygur Autonomous Region, PRC, with additional questionnaire data collected from approximately 40 households randomly selected from each of 16 villages within those communities. Yuanhucun and Ershilidian represent a combined area of 522.7 square km, and have 4,853 households with 25,684 inhabitants. Of those households, 69.9% are of the Han ethnic group, 22.1% Hui, 5.3% Uygur, and 2.7% Kazak. The total number of animals censused included 4,169 dogs, 41,369 sheep, 3,673 goats, 2,639 cattle, 5,400 pigs, 1,472 horses, and 59 donkeys. Levels of infection of the causative organism of cystic hydatid disease in various hosts were: dogs harboring Echinococcus granulosus tapeworms - 63 (16.2%) positive of 390 examined in 16 villages; domestic animals with hydatid cysts - 1,593 (88.6%) sheep of 1,797 examined, 69 (56.1%) of 123 goats, and 47 (94.0%) of 50 cattle; and 15 surgeries in inhabitants from 85 villages during the last 16 months prior to completion of the survey (annual case rate of 43.8/100,000). Questionnaire data collected from inhabitants in 16 villages showed that about 82% of the families owned at least one dog and 78% owned sheep. Of those families with sheep, most (84%) killed sheep for meat at least periodically, 76% had seen hydatid cysts in liver or lungs of butchered animals, and 77% routinely gave raw offal to their dog.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Investigation of the relationship between tyrosyl residues and the adenosine 5'-monophosphate binding site of rabbit liver fructose-1,6-biphosphatase as studied by chemical modification and nuclear magnetic resonance spectroscopy.

The effects of AMP, fructose 6-phosphate (Fru-6-P), fructose 2,6-bisphosphate (Fru-2,6-P2), and paramagnetic ions on the aromatic region of the proton nuclear magnetic resonance (NMR) spectrum of rabbit liver fructose-1,6-bisphosphatase have been investigated at 300 MHz. Two well resolved peaks in this region of the NMR spectrum are assigned to the protons from the aromatic ring of a tyrosyl residue of the enzyme by chemical modification with tetranitromethane and by nuclear Overhauser effects. Nitration of the tyrosyl residue causes desensitization of the enzyme to AMP inhibition as well as the loss of activity. In the presence of AMP during the modifications, 1 tyrosyl residue could be protected, presumably the one observed by NMR. Binding of AMP, an allosteric inhibitor of the enzyme, to rabbit liver fructose-1,6-bisphosphatase leads to an upfield shift of the tyrosyl proton signals in the NMR spectrum. No chemical shift or line broadening could be detected in the presence of the paramagnetic manganous ion, Fru-2,6-P2, or Fru-6-P. The negative intramolecular nuclear Overhauser effect from the ribose H2' proton to the adenine H8 proton of AMP suggested that AMP binds to the enzyme with an anti conformation about the glycosidic bond. The failure to observe intermolecular nuclear Overhauser effects between the tyrosyl residue and the protons of AMP indicates that the distances between them are greater than 4 A. On the basis of these observations, it is suggested that the AMP-related tyrosyl residue may be close to the AMP binding site, but it is not directly involved in ligand binding. Rather, the protection of this tyrosyl residue by AMP as observed by chemical modification experiments may well be due to a conformational change that results from covalent modification of the enzyme.

Adenosine Monophosphate↗
PubMed1989

The site of substrate and fructose 2,6-bisphosphate binding to rabbit liver fructose-1,6-bisphosphatase.

The binding site(s) in rabbit liver fructose-1,6-bisphosphatase for the active site binding ligand, fructose 6-phosphate, and the inhibitor, fructose 2,6-bisphosphate, have been investigated by using nuclear magnetic resonance spectroscopy. The distance from a nitroxide spin label to the bound ligands and the distance from the structural metal site to the bound ligands are about the same within experimental error. These data indicate that the two ligands probably bind at the active site in the rabbit liver enzyme.

Animals↗
PubMed1989

Ion-exchange equilibria of lysozyme, myoglobin and bovine serum albumin. Effective valence and exchanger capacity.

A series of ion-exchange equilibrium experiments were completed and analyzed by a mass action model. The isotherms at various counter-ion concentrations are regressed to determine the average number of binding sites, Z, the mass action constant, K, and the effective capacity of the exchanger, Pm. The estimates for Pm are 1-10 mmol of protein adsorbed per liter of packed Sepharose exchanger, in agreement with values determined from fitting the Langmuir isotherms. A geometric model, developed to relate the charge distribution of the exchanger and the size of the protein to the protein capacity, also confirms the estimates of Pm. The Z values estimated (and confirmed with an independent slope method) range from 0.8 to 3.6, indicating that most of the ionized sites on the protein do not undergo ion exchange. Geometric model estimates of exchanger sites covered by a protein at maximum surface coverage show that only 1-32% of the sites actually undergo ion exchange. This result indicates that adsorbed protein molecules "block" many exchanger sites, preventing other molecules from ion exchanging at those sites. This high degree of blocking by proteins also indicates that there is an excess of exchanger sites, as evidenced by Z showing no dependence on charge separation distance over the range 6-10 A. Scatchard pots of the equilibrium data indicate that there is competition between at least two different binding forms of each protein studied. For the high-affinity systems, cooperative binding was observed at low exchanger loading; the character then changed to heterogeneous competitive binding as the exchanger loading increased. The effect on an isotherm plot is a subtle but systematic deviation from the Langmuir and mass action models. More important, the competition means that Z represents an average for competing binding forms and, as such, Z can be fractional.

Chromatography, Ion Exchange↗
PubMed1989

Transcription factor ATF cDNA clones: an extensive family of leucine zipper proteins able to selectively form DNA-binding heterodimers.

An activating transcription factor (ATF)-binding site (consensus sequence 5'-GTGACGTACAG-3') is a promoter element present in a wide variety of viral and cellular genes. The two best-characterized classes of genes that contain ATF sites are E1A-inducible adenoviral genes and cAMP-inducible cellular genes. Here, we report the isolation of eight ATF cDNA clones, each of which is derived from a separate gene. All ATF cDNA clones examined contain a leucine zipper motif and are significantly similar to one another only within this region. The leucine zipper region of ATF proteins is also similar to that of the AP-1/c-jun family of transcription factors, whose DNA-binding site differs from the ATF-binding site at a single position. DNA binding studies reveal two mechanisms for generating further diversity from the ATF proteins. First, some, but not all, combinations of ATF proteins form heterodimers that efficiently bind to DNA. Second, although all ATF proteins bind to the ATF site, their precise interactions with DNA differ from one another, as evidenced by methylation interference analysis. Our results help to explain how a single promoter element, an ATF site, can be present in a wide variety of promoters.

Activating Transcription Factors↗
PubMed1989

Insulin-like growth factor binding proteins from cultured human fibroblasts. Characterization and hormonal regulation.

Specific, high affinity insulin-like growth factor (IGF) binding proteins are secreted by human fibroblasts in culture. By multiple criteria, the species of IGF binding proteins produced by human fibroblasts are distinct from the HepG2/amniotic fluid IGF binding protein, but share many characteristics with the growth hormone-dependent IGF binding protein forms predominant in normal adult human plasma. Treatment of cultured human fibroblasts with growth hormone produced an increase in IGF binding protein activity in the medium, while addition of glucocorticoids markedly diminished IGF binding activity. Insulin, epidermal growth factor, platelet-derived growth factor, and progesterone had no effect on IGF binding activity in fibroblast media. In comparison, HepG2 IGF binding activity was enhanced by progesterone, decreased by insulin, and unaffected by growth hormone or glucocorticoid treatment. Five molecular forms of IGF binding proteins were identified by Western ligand blots in human fibroblast conditioned medium, with Mr = 41,500, 37,000, 32,000, 28,000, and 23,000. In human fibroblast conditioned medium, the Mr = 41,500 and 37,000 IGF binding protein species were abundant, as in normal human plasma, with a major Mr = 23,000 form which was a minor component in plasma.

Animals↗
PubMed1989

Dynamic CT scan of intracranial tumors.

Of ninety-eight patients with intracranial tumors examined by dynamic CT scanning, 66 were confirmed operatively and pathologically. Our study showed that: 1) Dynamic CT can be performed safely and easily in outpatients; 2) Acoustic neurinoma, meningioma, pituitary chromophobe adenoma, astrocytoma and metastatic tumor have varying levels of time-density curves; 3) The tissue-blood ratio (TBR) at peak time (TBRp) is a useful indicator of the vascularity of tumoral tissues, and analysis of the time-density curve combining with TBRp is helpful to the differential diagnosis of tumors; 4) Differential diagnosis between tumors and vascular abnormalities such as aneurysm and arteriovenous malformation could be made easily with dynamic CT.

Adenoma, Chromophobe↗
PubMed1989

[Study of the effect of etoposide on the fluidity of dipalmitoylphosphatidylcholine liposome by differential scanning calorimetry and Raman spectroscopy].

The interaction of the anticancer drug, etoposide (VP16-213), with DPPC bilayer vesicles was investigated by DSC and Laser Raman techniques. The results present the fact that the incorporation of VP16-213 into aqueous dispersion of DPPC not only shifted the temperatures of phase transition towards higher value but also broadened the half-height width. The Raman spectra of the DPPC liposome in the C-H symmetric strech vibration lost intensity near 2850cm-1, therefore, it can be predicted that VP16-213 is localized at C1-C9 methylene region of the bilayer, which leads to the increase of the membrane's regularity and the decrease of its fluidity.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1989

[Influence of aminophylline on immune function of mice].

The effects of aminophylline (Ami) on immune systems in normal NIH mice were studied. Ami ig 25, 50 and 100 mg/(kg.d) x 8-10 d increased hemolytic ability of plaque forming cells and antibody concentration while it decreased the delayed type hypersensitivity (DTH) reaction and peripheral white blood cells phagocytosing function. Ami 1, 5, 10 micrograms/ml also promoted lymphocyte transformation of [methyl-3H] TdR incorporation induced by PHA in vitro.

Aminophylline↗