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Biomedical subjects

G Liu

Publications and source records attributed to G Liu.

At least 505 records · Page 28Linked to original sources
PubMed1996

Repeated recurrence of osteosarcoma treated by resections and chemotherapy.

This paper presents 5 patients with repeated recurrence of osteosarcoma (RROS). The primary focus of 3 patients were in the distal portion of femur, and 2 patients were in the proximal portion of tibia. Three patients, whose chest X ray film were negative, were treated by amputation and chemotherapy. Two patients had isolated metastatic focus 1.5 cm in diameter in lung, were treated by amputation after 1 week of chemotherapy and then treated by lobectomy after 2 weeks of chemotherapy. After operation, the chemotherapy was carried out for 3 courses of treatment. The roentgenogram of chest and affected limb were taken once every two months. There were metastatic focuses found in the lung of 1 patient and in the distal portion of femur of 2 patients. One patient was operated on for 4 times. Up to now, 3 patients have been living for 5 years and 2 patients for 6 years after operation.

Adolescent↗
PubMed1996

[The microscopic vasculitis in tongue].

This is the first report of 16 cases with microscopic vasculitis of the tongue in Chinese literatures. The clinical manifestations and histopathology of the disease were described. The treatment of promoting blood circulation to remove blood was used stasis. Probably the microscopic vasculitis plays an importment role in the glossodynia.

Aged↗
PubMed1996

[Exploration of certain factors affecting the airway resistance and its determination with interruption technique for normal old, middle-aged and young persons].

The airway resistance (Raw) was determined with interruption technique for 327 normal old, middle-aged and young persons after exploration of the effect of forced respiration, lung volume and upper airway compliance on it. FVC, V75, V50 and V25 were also performed. The regression equations of expiratory and inspiratory resistances (R. R1) were built with age, height and FVC as independent variables. The results showed that both expiratory and inspiratory resistances had a tendency of increase with aging, and FVC, V75, V50, V25 were declined with aging. This reflected that various organs and tissues including respiratory organs gradually oldened with aging. The decrease of elastic recoil of lung and central airway can lead to an increase of airway resistance in various degrees or no change. The data and regression equations can be recommended for the application in public health and clinical care.

Adult↗
PubMed1996

[An investigation on the changes of coagulation and fibrinolytic system in intensive infection with multiple organs failure].

An investigation was made for the significance of changes of coagulation and fibronolytic system in intensive infection with multiple system organ failure (MSOF). In 68 cases with various degrees of infection, hematological examinations, including estimation of PT, APTT, Fg, Fn and D-Dimer, activation of coagulation factor II, VII, X, XII (F II, F VII, F X, F XII), AT-III, PLG, alpha(2)-AP, t-PA and count of platelets were carried out. The results were as follows: In intensive infection with MSOF, PT and APTT increased significantly; activity of F II, F VII, F X and F XII decreased significantly platelet count and Fn decreased markedly; concentration of Fg and D-Dimer increased significantly; activity of PAI increased markedly; activity of t-PA and alpha(2)-AP decreased slightly. The incidence of MSOF not combined with DIC was 38.5%, but that combined with DIC was 79.7% (P < 0.01). It is suggested that DIC is the most important factor in the disorder of coagulation and fibrinolytic system. It play an important role in the pathogenesis and development of MSOF.

Adult↗
PubMed1996

[Studies on synthetic peptide. XX: the antigenicity and linear epitope map of synthetic peptide hepatitis C virus].

Hepatitis C virus (HCV), the major causative agent of post transfusion non-A, non-B hepatitis (NANB), had been cloned and expressed. According to the protein sequence of HCV-BK and its epitope profiles which combined the hydrophilicity, accessibility, flexibility, antigenicity, charge distribution and HPLC reserve coefficient of protein using the "Goldkey" computer program, we designed and synthesized the following peptides: P1(475-495), P3(449-468), P4(658-663), P5(645-663), P6(484-489), P7(475-489), P15(655-662), P16(230-237), P17(225-237), P18(1220-1240), P19(1694-1735), P24(1230-1240), P25(1482-1493), P26(384-389), P27(2355-2389). The results of ELISA showed that P6(60% positive results) and P19(63% positive results) testing with PT-HC of Gu An, Hebei province were the major antigens in NS1 and in NS4 region, respectively.

Antigens, Viral↗
PubMed1995

Effects of axial ligand replacement on the redox potential of cytochrome c.

The formal potentials (E0') and electron transfer numbers (n) of imidazole (Im), 1-methylimidazole (1-MeIm), and 1-ethylimidazole (1-EtIm) complexes of cytochrome c have been determined for the first time using optically transparent thin-layer spectroelectrochemistry. In comparing these results with the E0' value of the cytochrome c, their potentials at infinite dilution have been calculated, which indicate that axial replacement of methionine-80 by Im, 1-MeIm, and 1-EtIm gives rise to 426, 359, and 327 mV negative shifts relative to that of native cytochrome c, respectively. Thereby, the origins of the effects of axial substitution on redox potential are discussed.

2,6-Dichloroindophenol↗
PubMed1995

Three-dimensional functional magnetic resonance imaging of human brain on a clinical 1.5-T scanner.

Functional magnetic resonance imaging (fMRI) is a tool for mapping brain function that utilizes neuronal activity-induced changes in blood oxygenation. An efficient three-dimensional fMRI method is presented for imaging brain activity on conventional, widely available, 1.5-T scanners, without additional hardware. This approach uses large magnetic susceptibility weighting based on the echo-shifting principle combined with multiple gradient echoes per excitation. Motor stimulation, induced by self-paced finger tapping, reliably produced significant signal increase in the hand region of the contralateral primary motor cortex in every subject tested.

Brain↗
PubMed1995

Properties of synaptic transmission at single hippocampal synaptic boutons.

Synaptic transmission between individual presynaptic terminals and postsynaptic dendrites is a fundamental element of communication among central nervous system neurons. Yet little is known about evoked neurotransmission at the level of single presynaptic boutons. Here we describe key functional characteristics of individual presynaptic boutons of hippocampal neurons in culture. Excitatory postsynaptic currents (e.p.s.cs) were evoked by localized application of elevated K+/Ca2+ solution to single functional boutons, visually identified by staining with the vital dye FM1-43 (refs 6, 7). Frequent repetitive stimulation produced a decline in the incidence of e.p.s.cs as the pool of releasable vesicles was exhausted; typically, recovery proceeded with a time constant of about 40 s (23 degrees C), and involved a vesicular pool capable of generating about 90 e.p.s.cs without recycling. At individual synapses, synaptic currents were broadly distributed in amplitude, but this distribution was remarkably similar at multiple synapses on a given postsynaptic neuron. The average size of synaptic currents and of responses to focal glutamate application varied fourfold across different cells, decreasing markedly with increasingly dense synaptic innervation. This raises the possibility of a very effective mechanism for coordinating synaptic strength at multiple sites throughout the dendritic tree.

Action Potentials↗
PubMed1995

Binding of 1-methylimidazole to cytochrome c: kinetic analysis and resonance assignments by two-dimensional NMR.

The binding of 1-methylimidazole to the heme iron by displacing Met-80 of cytochrome c has been studied by two-dimensional (2D) exchange spectroscopy. Two components of cytochrome c ligated by 1-methylimidazole (1-MeIm-cyt c) are first identified, which are related to the sterically hindered orientation of 1-methylimidazole by the heme pocket. Based on a matrix formalism, the kinetic parameters are calculated from the 2D peak amplitudes. With the known resonance assignments of cytochrome c, some hyperfine shifted resonances arising from heme peripheral protons and two axial ligands, and some side-chain resonances of the aliphatic and aromatic protons of 1-MeIm-cyt c have been straightforwardly assigned, which provide a clue to ligand-induced electronic and molecular structural changes of the protein.

Cytochrome c Group↗
PubMed1995

Co-expression of urokinase, urokinase receptor and PAI-1 is necessary for optimum invasiveness of cultured lung cancer cells.

We investigated the importance of the urokinase (uPA)-plasmin system in fostering invasion of human lung cancer cells through artificial basement membranes composed of Matrigel. Eight cell lines (including 1 small cell and 7 non-small cell lines) were examined. One cell line did not express any components of the urokinase system. Four cell lines had substantial levels of endogenous uPA detectable on their surfaces. Three of these cell lines co-expressed the plasminogen activator inhibitor PAI-1 in addition to uPA. Assays for invasiveness revealed 4 cell lines capable of traversing a Matrigel barrier, including the 3 which co-expressed uPA, PAI-1 and uPA receptor. Surprisingly, the cell line expressing only uPA and uPA receptor displayed no invasive capacity despite levels of secreted uPA more than 20-fold higher than the other cell lines studied. Based on these observations, we hypothesized that both uPA and PAI-1 might be important for invasion by lung tumor cells, at least in vitro. We therefore tested polyclonal antibodies which inhibit uPA and PAI-1 activity for their effects on the highly invasive H292 cell line. After 3 days, invasive capacity was inhibited by antibodies to both uPA and PAI-1 in a dose-dependent manner. The plasmin inhibitor aprotinin reduced H292 cell invasion by 70%. Taken together, our data demonstrate that in cultured human lung cancer cells the uPA-plasmin system is important in promoting invasion into basement membranes and suggest that a critical balance between uPA and PAI-1 is necessary for optimal invasiveness. Our data are consistent with results from recent clinical studies showing that PAI-1 expression in tumor tissue is an adverse prognostic feature.

Carcinoma, Non-Small-Cell Lung↗
PubMed1995

Review of the multiple chemical exposure factors which may disturb human behavioral development.

Previous research both in humans and laboratory animals provides evidence that prenatal exposure to metals, pollutants and drugs may impair the neurobehavioral development of the offspring. This may induce mental and psychomotor disturbances as well as learning, behavioral and sensory disorders. However, proof for a strict causality between some low-level exposures to chemicals and behavioral developmental dysfunctions, is often considered still not to be established. The pertinent studies on neurobehavioral developmental toxicity of individual substances (lead, cadmium, organic solvents, PCBs, alcohol, nicotine, diazepam) are reviewed, and the methodologies and conclusions, the missing aspects and the existing problems which still need to be solved in further studies, are discussed. In addition, the necessity of undertaking a broad prospective cohort study on multifactorial influences on the behavioral development of children is emphasized.

Animals↗
PubMed1995

Better discrimination of hip fracture using bone density, geometry and architecture.

Bone density predicts the risk of hip fracture. Because hip strength is determined by bone geometry and architecture as well as density, we tested which variables in geometry and architecture were independent discriminators of hip fracture and, if combined with density, improved the discrimination of fracture from non-fracture over bone density alone. The design was a case-control study. The subjects were Caucasian women over the age of 60 years who had sustained a hip fracture after the age of 58 years (n = 22), and controls matched for age and weight (n = 43) and unmatched controls (n = 317) with no history of hip fracture. Variables in density, geometry and architecture were obtained from dual-energy X-ray absorptiometry images and from radiographs of the upper end of the femur. In a univariate model, of the measures of bone mass, the best discriminator of hip fracture was bone mineral density of the neck of femur; of the geometric measurements, it was hip axis length; and of the measurements of bone architecture, it was Singh grade. In a multivariate model, these three variables were shown to be independent discriminators of hip fracture. When hip axis length was combined with bone mineral density, there was significant improvement in discrimination of hip fracture (p = 0.014), and when Singh grade was combined with hip axis length and bone mineral density there was a further significant improvement (p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1995

Mixed pleomorphic-osteoclast-like tumor of the pancreas. Light microscopical, immunohistochemical, and molecular biological studies.

The morphological, immunohistochemical, and molecular biological features of a case of giant cell tumor of the pancreas are described. This neoplasm showed mononuclear and multinucleated tumor giant cells as well as numerous osteoclast-like cells with multiple foci of osteoid-osseous metaplasia. The pleomorphic and osteoclastic giant cells displayed extensive homologies in their immunohistochemical profiles. Neither the pleomorphic nor osteoclast-like portion of the tumor showed neither c-Ki-ras nor p53 mutation and did not express the mutated p53 protein. The results suggest that the pleomorphic and osteoclast-like components are histogenetically related and that this rare neoplasm originates from a precursor cell capable of differentiating along divergent cell type.

Aged↗