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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↗
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↗
PubMed1978

Alterations of body fluid compartments and distribution of tissue water and electrolytes in rhesus monkeys with rocky mountain spotted fever.

Chair-restrained rhesus monkeys (Macaca mulatta) were inoculated subcutaneously with 10(2)--10(3) plaque-forming units of virulent Rickettsia rickettsii. The latent period for fever and rickettsemia was three to four days; death occurred six to eight days after infection. Total circulatory electrolyte levels and fluid volumes, including plasma, red blood cell, true circulatory blood, and extracellular fluid, increased. The expansion of the extracellular and plasma volumes resembled findings reported during severe Rocky Mountain spotted fever in humans, guinea pigs, and rabbits. Total water content of the liver also increased. Intracellular concentrations of K+, as well as total Na+ and K+, decreased in the diaphragm. Both the lung and medulla oblongata showed increased levels of intracellular Na+ and water with simultaneously decreased levels of extracellular Na+ and water. Such an intracellular overhydration of the medulla oblongata could contribute to death as a result of depression of the cardiovascular and respiratory centers. On the basis of the findings in monkeys, the intravenous infusion of fluids and electrolytes during clinical therapy of severe rickettsial infections should be considered extremely dangerous.

Animals↗
PubMed1978

Distribution of tissue water and electrolytes in normal rhesus macaques.

Techniques for the determination of water and electrolytes in individual tissues of normal rhesus macaques (Macaca mulatta) are described. Base-line values are presented for intracellular and extracellular distributions of water and electrolytes in 14 tissues, including skin, skeletal muscle (gastrocnemius), cardiac muscle (left ventricle), lung, diaphragm, liver, renal cortex, outer medulla and inner medulla, cerebral cortex, cerebellum, thalamus-hypothalamus complex, medulla oblongata, and spinal cord.

Animals↗
PubMed1978

Effect of staphylococcal enterotoxin B on cardiorenal functions in rhesus macaques.

Selected cardiovascular and renal functions were measured for 5 hours in conscious, chair-restrained, female rhesus macaques (Macaca mulatta) after IV (0.05 and 1.0 mg/kg) or oral (1.0 mg/kg) administration of staphylococcal enterotoxin B (SEB). Cardiovascular functions, renal hemodynamics, and renal metabolism were also studied between 6 and 11 hours after IV SEB inoculation. Oral SEB produced few changes in cardiorenal functions. In contrast, IV SEB produced hypotension, tachycardia, increased total peripheral and renal vascular resistance, and decreased cardiac and renal functions. The early significant (P less than 0.05) renal depression was not associated with hypotension (mean arterial blood pressure greater than 100 mm of Hg). However, all measured renal functions except extraction ratio of PAH were positively correlated with decreased blood pressure (r = 0.52 - 0.71) in the later phase of SEB toxemia. It is concluded that the kidney is one of the organs affected by IV SEB. Renal impairment may partially contribute to death during SEB enterotoxemia in macaques.

Animals↗
PubMed1978

Effect of staphylococcal enterotoxin B on cardiorenal functions and survival in X-irradiated rhesus macaques.

Pretreatment of rhesus macaques with nonlethal total-body x-irradiation (400 R) prolonged survival time from an average of 15 hours to 101 hours after intravenous (IV) inoculation of 50 microgram of staphylococcal enterotoxin B (SEB)/kg of body weight. Radiation exposure per se did not produce detectable cardiorenal changes; however, the longer survival after SEB challenge exposure in x-irradiated rhesus macaques was associated with improved cardiorenal functions if compared with that of nonirradiated macaques given the same dose of SEB. Total-body radiation exposure 4 days prior to IV SEB inoculation prevented typical SEB-induced decreases (where measured at 5 hours) in cardiac output, stroke volume, TcH2O, CPAH, Cosm, and urine flow, as well as increases in total peripheral and renal resistance. A theory concerning the significance of radiation-induced leukopenia on modification of SEB-induced cardiorenal functions is postulated.

Animals↗