Biomedical subjects

C T Liu

Publications and source records attributed to C T Liu.

At least 19 recordsLinked to original sources

PubMed1992

The effect of insulin-like growth factor II on glucose uptake and metabolism in rat skeletal muscle in vitro.

The effect of insulin-like growth factor II (IGF II) on the rates of lactate formation, glycogen synthesis and glucose transport in the presence of a range of concentrations of insulin were investigated using an isolated preparation of rat skeletal muscle. IGF II, at a concentration of 65 ng/ml, caused a small but significant increase in the rates of these processes at a basal physiological insulin concentration (10 muunits/ml), but was without effect in the presence of 1, 100, 1000 or 10,000 muunits of insulin/ml. Hence IGF II increased the insulin sensitivity of this tissue. This effect was removed if the incubation medium was supplemented with an equimolar concentration of IGF binding protein 1 (BP1). It is suggested that changes in the concentration of IGF II and/or BP1 may regulate glucose uptake and metabolism in skeletal muscle and have physiological significance in the control of blood glucose level.

Animals↗

PubMed1992

Metabolism of platelet-activating factor in neutrophils isolated from Pichinde virus-infected guinea pigs.

Metabolism of platelet-activating factor (PAF) was studied in cultured polymorphonuclear neutrophils (PMNs) obtained from Pichinde virus-infected strain 13 guinea pigs. Neutrophils obtained from control and infected guinea pigs on postinoculation days 10 and 14 were incubated with [3H]lyso-PAF, [3H]PAF, or [3H]acetate. After incubation for 1 h at 37 degrees C, formation of [3H]acyl-PAF from either [3H]lyso-PAF or [3H]PAF increased significantly in PMNs from infected guinea pigs compared to control PMNs. Furthermore, total radioactivity from [3H]lyso-PAF or [3H]PAF was higher in PMNs from infected animals than in those from controls. However, compared to PAF production by control PMNs, production of PAF by infected PMNs was unchanged. These results suggest that PMNs may not be the major source of increased blood PAF levels during Pichinde viral disease.

Acetates↗

PubMed1992

Possible involvement of endogenous beta-endorphin in the pathophysiological mechanisms of Pichinde virus-infected guinea pigs.

Previously, we demonstrated that naloxone, an opiate antagonist, prolonged survival of strain 13 guinea pigs infected with Pichinde virus. Thus, endogenous opiates may be involved in the pathogenesis of this viral disease. To determine whether endogenous opiate levels were affected by Pichinde viral infection, beta-endorphin concentrations in plasma and cerebrospinal fluid (CSF) of normal and infected strain 13 guinea pigs were measured by radioimmunoassay. Cerebrospinal fluid beta-endorphin concentrations were 78.0 +/- 13.2 pg/ml on postinoculation day (PID) 7, 59.0 +/- 5.6 pg/ml on PID 12, and 58.8 +/- 5.4 pg/ml on PID 14. These values were significantly higher than baseline levels of CSF beta-endorphin: 30.8 +/- 1.9 pg/ml. Plasma beta-endorphin concentrations of infected animals increased significantly to 202.1 +/- 17.9 pg/ml on PID 7 and to 154.2 +/- 21.4 pg/ml on PID 12 from a mean baseline value of 84.2 +/- 13.1 pg/ml. After a primer intravenous injection of beta-endorphin (10, 15, or 30 micrograms/kg), followed by constant infusion of beta-endorphin (15, 45, or 90 micrograms/kg.hr) to control noninfected guinea pigs, heart rate (except with the lowest dose) and mean blood pressure decreased markedly. Under these experimental conditions, concentrations of plasma and CSF beta-endorphin increased simultaneously with different magnitude. Because both Pichinde viral infection and beta-endorphin administration produced a similar trend of cardiovascular disturbances, leading to hypotension and bradycardia, increased concentrations of plasma and CSF beta-endorphin may play a partial role in the pathophysiological mechanisms of Pichinde virus infection.

Animals↗

PubMed1992

[Clinical evaluation of the metabolism and imaging of the lung in the patients with chronic obstructive pulmonary diseases using 131I-HIPDM].

The accumulation of venously injected 131I-HIPDM in the rat lung was observed. In this article we report the results of application of 131I-HIPDM in the patients with COPD. The results showed that the metabolism and development of 131I-HIPDM in the lung reflected on condition of the pulmonary endothelial cells or receptors. The clearance curve of HIPDM displayed that COPD, especially COPD of smokers was slow. The analysis of the lung clearance of 131I-HIPDM forms a new index of lung dysfunction.

Adult↗

PubMed1992

Cardiovascular responses to intracerebroventricular infusion of artificial cerebrospinal fluid in anesthetized strain 13 guinea pigs.

The cardiovascular effects of constant intracerebroventricular infusion in anesthetized strain 13 guinea pigs were studied. Bilateral cerebroventricles of the animals were catheterized stereotaxically with two 20-gauge blunt needles, penetrating 5 to 6 mm into the skull. Baseline cerebroventricular pressure values were 1.3 +/- 0.6 mmHg. After artificial cerebrospinal fluid was infused into the left ventricle at 0.5 ml/h, left cerebroventricular pressure increased to 8.1 +/- 1.6 mmHg (P less than 0.01), while right cerebroventricular pressure reached 5.6 +/- 2.2 mmHg within 20 minutes. No significant changes in mean blood pressure or heart rate were observed. When intracerebroventricular infusion rate increased to 5.0 ml/h, cerebrospinal fluid pressures of left and right cerebroventricles increased to 40.0 +/- 4.8 and 38.4 +/- 4.7 mmHg within 10 minutes from baseline values of 1.5 +/- 0.5 and 1.7 +/- 0.7 mmHg, respectively. Simultaneously, mean blood pressure and heart rate increased from 72 +/- 4 to 101 +/- 9 mmHg and from 195 +/- 11 to 218 +/- 17 beats/min, respectively. However, 30 to 50 minutes later, mean blood pressure, heart rate, and cerebrospinal fluid pressure decreased abruptly, and two of four animals died. We suggest that this technique with a low infusion rate (less than 0.5 ml/h) can be used to deliver certain drugs into the brain ventricles directly without producing undesirable effects on blood pressure or heart rate.

Anesthesia↗

PubMed1992

Increased platelet-activating factor (PAF) concentrations in hearts and lungs of Pichinde virus-infected guinea pigs.

Platelet-activating factor (PAF) has been implicated as a cause of cardiopulmonary disturbances in certain diseases. In the present study, concentrations of PAF in hearts, lungs, whole blood, and other organs of control and Pichinde virus-infected guinea pigs on post-inoculation days (PID) 10 and 14 were measured by radioimmunoassay. Results were further confirmed by bioassay after separation and purification with thin-layer chromatography. PAF concentration in the hearts and lungs of virus-infected animals increased significantly on PID 10 and 14, as compared with control levels. PAF level in the blood of infected guinea pigs also significantly increased on PID 14. There was little change of PAF levels in liver and kidney after viral inoculation. Increased PAF concentrations in both hearts and lungs of infected strain 13 guinea pigs suggest that this lipid mediator may play an important role in the development of cardiopulmonary disturbances.

Animals↗

PubMed1992

Acute ethanol administration and the metabolism of glutamine by skeletal muscle of the rat: implications for ethanol-induced reductions in protein synthesis.

The effect of acute ethanol administration (75 mmol/kg) on the metabolism of glutamine by skeletal muscle of the rat was studied in order to investigate the hypothesis that the concentration of this amino acid in muscle controls the rate of protein synthesis. Ethanol administration was without effect on the concentration of glutamine in EDL (extensor digitorum longus) and plantaris muscles (Type II fibre-rich muscles), but increased the concentration in soleus muscle (Type I fibre-rich muscle). The rate of release of glutamine was increased from EDL muscle, but unchanged from soleus muscle of treated animals. Ethanol administration was without effect on the maximal activity of glutamine synthetase in both soleus and EDL muscles. It is concluded that changes in the concentration of glutamine in muscle cannot explain the ethanol-induced changes in the rate of protein synthesis. Nevertheless, the increase in the concentration of glutamine in soleus muscle following ethanol administration is of interest and may be mediated via modulation of the glutamine transporter and/or the activity of glutamine synthetase in vivo.

Alanine↗

PubMed1992

[Lung function changes during pregnancy].

The lung functions in different pregnant stages were measured in 41 women with pregnancy and 12 normal women without pregnant. Forced Vital Capacity (FVC) was found gradually decreasing as pregnancy advanced (P less than 0.05). After 28 weeks of gestation, the Vital Capacity (VC), Forced Expired Volume in 1 second (FEV 1) significantly decreased as compared with the normal values (P less than 0.01 or P less than 0.05). These results suggested that the lung function changed gradually during pregnancy, especially after the 28th week, significantly in VC, FVC and FEV 1. Maybe there are slight obstructions in the bronchial tubes. After the 28th week of gestation and it may be the reason for occurrence of breathshort and the lung infection.

Adult↗

PubMed1991

From san gu liu po to 'caring scholar': the Chinese nurse in perspective.

This study presents a re-evaluation of the origins of Chinese nursing from the earliest traditional carers to the mature, professionalized institution of the republican period. The influence of traditional cultural values on the nature of the modern profession is discussed and its emergence considered in historical context with particular attention to the role of missionaries, philanthropic institutions and other aspects of foreign intervention, both European and Japanese. The Chinese anti-imperialist response, as stimulated by the 'May 4th Movement' and later the Sino-Japanese war, is shown to be an important ingredient in the transition from foreign to national control of the profession and in its achieving respect. Some doubt is cast on the assumption that Chinese nursing has followed a process of rapid convergence to the Western model.

China↗

PubMed1991

Technique for repeated collection of cerebrospinal fluid from cisterna magna of anesthetized strain 13 guinea pigs.

To study biochemical changes in cerebrospinal fluid (CSF), we developed a reliable technique for repeated collection of CSF in anesthetized strain 13 guinea pigs. The animal's head was mounted in a stereotaxic instrument with ventral tilt at 30 degrees, and cisternal puncture was made with an L-shaped, 23-gauge needle through the shaved skin. Clear CSF was collected in a 1-ml syringe surrounded by crushed ice. Each collection procedure lasted for 3 min, and three consecutive collections produced about 0.2 ml of CSF. Sampling was repeated at 3-hr intervals. With intravenous saline infusion (10 ml/kg.hr), a total volume of 0.6-1.0 ml of CSF was collected over 6 to 12 hr. Animals maintained a mean blood pressure, heart rate, and minute volume, with few changes during CSF sampling for the entire collection.

Animals↗

PubMed1991

Pulmonary responses of conscious strain 13 guinea pigs to Pichinde viral infection.

A laboratory animal model for studying pulmonary responses to arenaviral infection was established with advanced technologies. Tidal volume (TV), respiratory rate (RR), minute volume (MV), expiratory time (TE), inspiratory time (TI), peak expiratory flow (PEF), and specific pulmonary airway resistance (RES) were measured with a double plethysmograph and a computer data-acquisition system in six conscious, strain 13 guinea pigs. Using the same animal, experiments were conducted before and after subcutaneous inoculation with 10(4) plaque-forming units of Pichinde virus. Pulmonary functions were determined for 1 minute every 10 minutes for 2 hours before and at postinoculation days (PID) 3, 6, 8, and daily thereafter until shortly before death. The mean time to death was 18 +/- 0.7 days. Tidal volume, RR, MV, PEF, RES, and rectal temperature increased slightly on PID 3 and reached peak values at the midpoint of disease. At 95% of the mean time to death (16.5 +/- 0.5 days), RR, MV, and rectal temperatures suddenly decreased to lower than baseline values; while TV, RES, and PEF values remained high. When TE decreased with the increase in RR, TI did not change. When RR decreased at the terminal stage, both TE and TI increased. Hyperventilation, increased specific pulmonary airway resistance, terminal hypoventilation, and respiratory arrest were noted in strain 13 guinea pigs infected with Pichinde virus.

Airway Resistance↗

PubMed1990

[A preliminary study on the role of interleukin-1 in chronic lung disease].

Pulmonary alveolar macrophages (PAM) obtained by bronchoalveolar lavage in 13 normal individuals, 17 lung cancer patients and 10 patients with chronic obstructive pulmonary disease (COPD) were incubated in vitro for 24 hours. Every specimen was divided into two portions and lipopolysaccharides were used to stimulate PAMs to produce interleukin-1 (1L-1) in one. The levels of 1L-1 in normal subjects were 5547.65 +/- 2420.42 cpm/10(6) cells (stimulated) and 718.46 +/- 472.25 (unstimulated), which were higher than the 2733.20 +/- 1611.17 (stimulated, P less than 0.01) and 327.57 +/- 226.86 (unstimulated, P less than 0.05) in lung cancer patients, but lower than that of 8716.26 +/- 2977.66 (stimulated, P less than 0.05) in COPD patients. The enhanced 1L-1 activity in COPD patients might contributed to the active inflammatory process and tissue destruction of COPD. Our findings that 1L-1 activity in patients with bronchogenic carcinoma was decreased may reflect the local immune deficiency in malignant disease. The release of 1L-1 by PAMs stimulated by smoking was suggested to be associated with the development of COPD, but its role in immune response has to be determined.

Aged↗

PubMed1989

Changes in body weight and body surface area in strain 13 guinea pigs infected with Pichinde virus.

In studying pathogenetic mechanisms of Pichinde virus-induced disease in strain 13 guinea pigs, a large decrease of body weight (approximately 28%) observed within 14 days postinoculation raises a question concerning the validity of standardizing body or organ functions in terms of body weight. This study was to examine changes in body weight and body surface area of Pichinde virus-infected strain 13 guinea pigs after various days postinoculation. Control guinea pigs were also subjected to the same experimental procedures and experimental days. While body weights and body surface areas increased progressively in controls, I observed only slight decreases in body surface areas (4-6%) in the infected guinea pigs, despite large decreases of body weights throughout the 14-day experimental period. In conclusion, Pichinde virus-infected strain 13 guinea pigs demonstrated a small reduction of body surface area within 14 days postinoculation, suggesting that body surface area, rather than body weight, should be used for standardizing body or organ functions for comparison with their own baseline values.

Animals↗

PubMed1989

Effect of ethanol on natural killer cell activity in vitro.

The effect of ethanol on kinetic stages of natural killer (NK) cell activity was studied in vitro. Peripheral blood mononuclear cells (MNC) were either co-cultured or pre-incubated with various ethanol concentrations and assayed for NK cell activity with a "4-hour chromium release assay" and a "single cell cytotoxicity assay in agarose" simultaneously. Direct addition of ethanol to the assay system resulted in a dose-dependent inhibition of NK cell activity. The percentage of lysed conjugated target cells was suppressed from a control value of 21.2% to 17.0%, 15.1%, 11.8% and 10.0% with an ethanol concentration of 0.125%, 0.25%, 0.5% and 1.0%, respectively. NK cell recycling was also inhibited. A 24-hour pre-incubation with ethanol, however, resulted in NK cell activity enhancement. The enhancement was around 20% with a 0.25% ethanol concentration and around 45% with a 0.5% and a 1.0% ethanol concentrations. The enhancing effect was noted mainly at the cytolysis stage after binding of effector cell with target cells.

Cells, Cultured↗

PubMed1988

Transforming genes in duck hepatic carcinoma--mht(raf) and Ha-ras.

The transfection of NIH 3T3 cells was performed with DNAs from 2 duck primary hepatic carcinomas (DHC 40K, 9K) and 1 tumor-adjacent liver tissue (TAL, 9N). Transfectants were found from 40K, 9K and 9N DNAs. The secondary transfectants were obtained after transfection of RAT-1 cells with DNAs from primary transfectants. After hybridization with Ha-ras, Ki-ras, N-ras and mht oncogenes, it was found that duck mht (5.2 and 3.2 kb EcoRI fragments) and duck Ha-ras (3.4 kb EcoRI fragments) were present in all these transformants. This is the first report on transforming genes in duck primary hepatic cancer as well as tumor-adjacent liver tissue.

Animals↗

PubMed1987

Observation of the in situ contracting heart of guinea pigs infected with Pichinde virus.

The in situ beating hearts from anesthetized control and Pichinde virus-infected strain 13 guinea pigs, between days 7 and 19 postinoculation, were directly observed and video recorded. Although some hearts from Pichinde virus-infected animals were visually depressed and had altered contraction patterns, such a pronounced cardiac dysfunction was not associated with any marked histopathological changes in the cardiac tissue. The manifestations of cardiac dysfunction were limited mainly to the right side of the heart and occurred only from days 11 to 19 postinoculation. We suggest that certain biochemical "lesions" in the heart after lethal Pichinde virus infection may be present, which may have been caused by the actions of endogenous pathogenic mediators and an overall metabolic deficiency of the infected body.

Animals↗

PubMed1986

Inhibition of overall protein and RNA synthesis as a mechanism for the tunicamycin induced decrease in cytochrome P-450 in rat hepatocytes.

In rat hepatocytes maintained in culture, cytochrome P-450 and NADPH cytochrome c reductase activities were decreased by tunicamycin in a dose and time dependent fashion. The effect of tunicamycin was mainly due to inhibition of protein synthesis. Tunicamycin decreased L-[35S] methionine incorporation into many proteins, including a 52 kDa cytochrome P-450 isozyme. Tunicamycin also reduced RNA synthesis. These results indicate that tunicamycin decreased cytochrome P-450 levels in hepatocytes by inhibiting protein and RNA synthesis.

Animals↗

PubMed1979

Effects of intravenous injection of leukocytic endogenous mediator on cardiohepatic functions in rhesus macaques.

A crude preparation of leukocytic endogenous mediator administered IV over a 10-minute period into a rhesus macaque at a dosage of 10 ml/kg of body weight resulted in hypotension, tachycardia, vasodilation, hypoalbuminemia, and hypoproteinemia. Decreases in cardiac and hepatic functions and biphasic changes in peripheral polymorphonuclear leukocytes also were seen. All measured changes, except hepatic functions and plasma albumin values, returned to base-line values within 24 hours. Data indicate that presently utilized crude leucocytic endogenous mediator preparations contain a heretofore undescribed, and as yet unidentified, component. Induced early cardiovascular changes may be related in part to certain compounds likely to be in the crude preparation.

Animals↗