ABSTRACT
monocarboxylate transporter (MCT) are vital transmembran e transporters involved in multiple cellular functions including the regulation of intracellul ar pH and lactate transport. At least eight isoforms of MCT have been cloned and characterized to date, they constitute a new gene family of mammal transporters . These isoforms have the differences in substrate and inhibitor specificities a nd tissue distribution. Thus it may provide a new way of diagonosis and treating for dieases such as cancer by investigating on the structure and function and r egulational mechanism of MCT.
ABSTRACT
Objective To study the effect of transfecting anti-sense expression vector of the first subtype of the monocarboxylate transporter (MCT1) gene into human lung adenocarcinoma cells on intracellular pH (pHi) regulation, lactate transportation and cell growth. Methods MCT1 antisense gene recombinant vector pLXSN-MCT1 was introduced into human lung cancer cells A549 with electroporation. The cell colonies resistant to G418 were selected. Positive clones were examined by PCR to confirm the integration of genomic A549 DNA and antisene MCT1 gene. The changes of pHi and lactate transportation were detected with spectrophotometry. Cell growth was studied with cell growth curve. Results pHi and lactate transport were remarkably decreased in the transfected cells, and the cell growth was inhibited compared with the cells without transfection（P<0.001）. Conclusion MCT1 gene may play an important role in pHi regulation, lactate transport and cell growth in lung tumor cells.
ABSTRACT
After electrical stimulation of the phrenic nerve,the function of the diaphragm was assessed by measurement of the transdiaphragmatic pressure (PDi),establishment of the Pdi-sti-mulating frequency (F) curve,and analysis of the power spectrum on the diaphragmatic elec-tromyogram (EMGdi) at spontaneous breathing.Hypercapnia of the dogs was induced by forcing the animals to inhale a mixture of CO2 and air.The findings were as follows:(1) After acute hypercapnia,PDi rapidly and progressively decreased.The power spectrum of EMGdi was also reduced.The PDi-F curve was shifted to right.These findings suggest that the function of the diaphragm was severely damaged.(2) The decrease of pH value was the important cause of diaphragmatic fatigue.(3) The diaphragm in a static condition could reduce the damage of hypercapnia.(4) Cedi-lanid exerted certain effects on the prevention of diaphragmatic fatigue created by acute hypercapnia.
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After the bilateral phrenic nerves of the dogs were stimulated,the effect of amino-phylline on the function of normal and fatigued diaphragm was observed with the determination of transdiaphragmatic pressure-stmulation frequency curve (Pdi-F).and the analysis of the power spectrum of diaphragmatic electromyogram (DMGdi) at spontaneous breathing.After the administration of 10 and 20 mg/kg of aminophylline ,the PDi pf the normal diaphragm was increased and that of the fatigued diaphragm recovered.The Pdi-F curve of the fatigued diaphragm was shifted to the left,and the central frequency,the medium frequency,and the high/low frequency ratio were markedly increased.It is concluded that aminophylline at the therapeutic dosage can imporve the generation of the strength and enhance the recovery of the fatigued diaphragm.
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The fatigue of the diaphragm was determined with electromyography ir.35 patients with chronic obstructive emphysema (COPD) and in 47 nomaJ subjects serving as the control.It was found that the high/low frequency ratio (H/L) and the central frequency (Fc) of the diaphragmatic electromyogiam (EMGdi) were markedly decreased after diaphragmatic fatigue in COPD patients as well as in the controls ( P
ABSTRACT
The respiratory distress syndrome (RDS) model induced by oleic acid injection in dogs and treated by anisodamine were observed. The blood gas parameters, pulmonary arterial pressure, pulmonary wedge pressure, blooe cell count, neutrophil aggregation, platelet aggregation activation, thromboxane B2, 6-keto-PGF1? and hemocoagulograms were studied in order to determine the pathophy-siological mechanism and the effect of auisodamine. The complement activation and neutrophil aggregation induced by C3a and thromboxane A2 are likely the initiation factors of RDS; lung injuries were complicated with disseminated intravas-cular coagulation and anisodamine exerts certain therapeutic effect on RDS.
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AIM: The expression of the Fas Antigen and induction of apoptosis by anti-Fas antibody in esoinophils in vitro were investigated. METHODS: Purified eosinophils from health donors were cultured for 72 h in the presence of human IL-5 and with or without anti-Fas monclonal antibody (MoAb) at various concentrations (1-1000 ?g/L). The expression of the Fas antigen on eosinophils was determined by immunocytochemistry. The changes of eosinophils viability and apoptosis were also studied. RESULTS: The Fas antigen was expressed on freshly isolated eosinophils, which had no significant changes after culture in the presence or absence of IL-5. The anti-Fas MoAb at different concentration suppressed significantly the IL-5-mediated eosinophils survival (78%?9%). When eosinophils were cultured in the presence of IL-5 (1?10 4 U/L) with anti-Fas MoAb (1 000 ?g/L), the percentage of alive cell decreased to 30%?12%( P
ABSTRACT
The study on the functions of the diaphragm has been carried on for 5 years.It consisted of the studies on the relationship of the tension and endurance of inspiratory muscles with pulmonary functions,the changes of diaphragmatic electromyogram in maximal ventilation volume test in normal subjects and patients with chronic obstructive pulmonary disease(COPD),the functional changes of the diaphragm in dogs with RDS and the therapeutic effects of aminophylline.the changes of diaphragmatic electromyogram in dogs with hypoxemia and hy-percapnia,determination of transdiaphragmatic pressure,the relationship of the stimulation frequency on the phrenic nerve with diaphragmtic fatigue,etc.It was found that there existed di-aphragmtic fatigue in dogs with RDS,in dogs with hypoxemia and hypercapnia,and in patients with COPD,and aminophylline,digoxin,salbutomal ?-receptor excitory agents can minimize or prevent diaphragmatic fatigue.
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The antigens(3C9Ag)which could be recognized by the anti-lung cancer monoclonal antibody 3Ca were assayed with BA-ELISA immunobinding inhibition test in 50 lung cancer patients,21 patients with non-cancerous pulmonary diseases and 40 normal subjects.Meanwhile radioimmunoassay was used to determine serum CEA.It was found that the sensitivity,specificity and accuracy for 3C9Ag to diagnose lung cancer were 76%,90.5% and 80.3% respectively.Much higher positive rates could be found in NSCLC patients and in those with stage Ⅱ or Ⅲ cancer.3CsAg was superior to CEA in its sensitivity and accurracy.Combined assay with 3C9Ag and CEA could increase the positive rate.
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Twenty-five hybrid dogs were injected intravenously with oleic acid of the dose 0.3 ml/kg of body weight to prepare a model of respiratory distress syndrome (RDS) . The animals were killed 24 hours after injection. PaO2, PaCO2 and pH of the arterial and mixed venous blood were determined before and immediately, 0.5, 1?2, 4, 6, 22 and 24 hours after injection. The average pulmonary arterial pressure was measured hourly. The chest x-ray films were taken 2,4, 6 and 24 hours after injection. The electrolytes T3, T4, the hematocrit and RBC count, and the serum corticosteroid level were measured before and 24 hours after injection.25 dogs were divided into two groups; the control group consisted of 8 dogs and the therapeutic group consisted of 17 dogs, among which nine were treated with hyosine hydrobromide and 8 with dexamethasone. The histologic specimens of the animals of the control group and hyosine hydrobromide treated group were examined with both light and electron microscopes but the specimens of the animals of dexamethasone treated group were examined with light microscope only.It was found that dexamethasone is effective in the treatment of RDS produced with oleic acid injection while hyosine hydrobromide is of no value.
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The therapeutic effects of prostaglandin E1 on respiratory distress syndrome induced with homogeneous fat extraction were observed in dogs.It was found that prostaglandin E1 could alleviate hypoxemia,reduce pulmonary capillary permeability,and attenuste pulmonary edema.The mechanism of the therapeutic efficiency of prostaglandin E1 on pulmonary damages is that prostaglandin E1 can inhibit the adherence of polymorphonuclear netttrophils and the genesis of oxygen free radicals,and protect the pneumocyte type Ⅱ.
ABSTRACT
Homogenous fat extract was injected through the femoral vein to induce respiratory distress syndrome in 15 dogs. It was found that the changes of blood gases, chest x-ray films, and lung pathology of the dogs were similar to those of adult respiratory distress syndrome.The pathogenesis was extensive pulmonary fat embolism with complement activation and free radicals formation. Vitamin E was consumed during antiperoxidation. It is believed that this model serves better for the study of respiratory distress syndrome.