ATPase Activity In Group Research Articles

Disruption of Intracellular ATP Generation and Tight Junction Protein Expression during the Course of Brain Edema Induced by Subacute Poisoning of 1,2-Dichloroethane.

The aim of this study was to explore changes in intracellular ATP generation and tight junction protein expression during the course of brain edema induced by subacute poisoning of 1,2-dichloroethane (1,2-DCE). Mice were exposed to 1.2 g/m3 1,2-DCE for 3.5 h per day for 1, 2, or 3 days, namely group A, B, and C. Na+-K+-ATPase and Ca2+-ATPase activity, ATP and lactic acid content, intracellular free Ca2+ concentration and ZO-1 and occludin expression in the brain were measured. Results of present study disclosed that Ca2+-ATPase activities in group B and C, and Na+/K+-ATPase activity in group C decreased, whereas intracellular free Ca2+ concentrations in group B and C increased significantly compared with control. Moreover, ATP content decreased, whereas lactic acid content increased significantly in group C compared with control. On the other hand, expressions of ZO-1 and occludin at both the protein and gene levels in group B and C decreased significantly compared with control. In conclusion, findings from this study suggest that calcium overload and depressed expression of tight junction associated proteins, such as ZO-1 and occludin might play an important role in the early phase of brain edema formation induced by subacute poisoning of 1,2-DCE.

Effects of electroacupuncture of different intensities on cerebral energy metabolism in a rat model of global cerebral ischemia-reperfusion

Objective To investigate the effects of electroacupuncture (EA) of different intensities on cerebral energy metabolism in a rat model of global cerebral ischemia-reperfusion (I/R) . Methods Forty male SD rats weighing 200-230 g were randomized into 5 groups ( n = 8 each) : group A sham operation; group B global cerebral I/R and C, D, E groups cerebral I/R+ 5, 3, 1 mA EA. Global cerebral I/R was induced by 4-vessel occlusion technique. Bilateral vertebral arteries were permanently occluded by cauterization.Bilateral common carotid arteries were clamped. When the bilateral pupils were completely dilated, the arteries were unclamped. Baihui,Mingmen and Zusanli were electrically stimulated with 5,3,1 mA (30-50 Hz) for 20 min at 1 h of reperfusion in C, D, E groups. The EA was repeated at 12 h of reperfusion. The animals were sacrificed at 24 h of reperfusion.The activities of Na+ -K+ -ATPase, succinodehydrogenase (SDH) and lactic dehydrogenase(LDH) in brain tissue were measured.Results Cerebral I/R significantly increased LDH activity and decreased Na+ -K+ -ATPase activity in group B as compared with group A. EA with 5 mA significantly decreased LDH activity and increased SDH and Na+ -K+ -ATPase activities in group C compared with group B. Conclusion EA can improve the cerebral energy metabolism in a rat model of global cerebral I/R and it is related to the intensity, which may be the mechanism by which EA reduces the global cerebral I/R injury. Key words: Electroacupuncture; Reperfusion injury; Energy metabolism; Brain

Effect of CD8(+)CD28(-) suppressor T cells induced by dendritic cell with major histocompatibility complex 1 expression RNA interference on immune tolerance in rat intestinal transplantation

To investigate the effect of CD8(+)CD28(-) suppressor T cells(Ts) induced by dendritic cell(DC) with major histocompatibility complex 1(MHC-1) expression RNA interference on immune tolerance in rat intestinal transplantation. The expression level of CD8(+)CD28(-)Ts were successfully induced by DC with MHC-1 expression interfered by RNA interference technique under the stimulator of allograft antigen. Orthotopic intestinal transplantation was performed in 36 rats by modified three cuffs method. The recipients were randomly divided into three groups(12 rats in each group):group A was experimental group with CD8(+)CD28(-) Ts being administrated, mixed T cells were injected in group B, while in group C, NS were administrated. On the first day and the seventh day posttransplant, the 36 rats of the 3 groups were administrated through vena dorsalis penis respectively. Six rats were selected randomly from each group and the animals were sacrificed on the 14 th day postoperatively, serum levels of TGF-beta, IFN-gamma and the values of Na(+)-K(+)-ATPase activity of the intestinal graft were assayed and the intestinal pathologic morphology, intestinal allograft survival were observed concerning the remainders. On the 14 th day after operation, the expression levels of TGF-beta and IFN-gamma in group A were significantly up-regulated as compared with those in group B and group C(P<0.05). Na(+)-K(+)-ATPase activity in group A was(6.3+/-1.0) kU/g, much higher than the levels of group B(3.6+/-0.9)kU/g and group C(2.9+/-1.3) kU/g and the differences were significant(P<0.05). The data suggested preliminarily that pathological scores of intestinal graft in group A were lower than those in group B and group C. The survival time of the recipients in group A was 32.0 days, much longer than that in group B (17.5 days, P<0.05) and group C(21.0 days, P<0.05). CD8(+)CD28(-) Ts induced by DC with MHC-1 expression RNA interference can alleviate acute rejection and lead to immune tolerance in rat intestinal transplantation.

Lung transplantation by continuous perfusion in an experimental auto-transplant animal model.

The aim of this study was to evaluate the preservation of the lung using the cold flushing technique in association with continuous perfusion of the organ during static hypothermic storage. In the first phase, the hearts and lungs of 5 New Zealand rabbits were removed three hours after establishing brain death. The left lungs were each conserved in 200 ml of low-potassium UW solution at 10 degrees C for 3 hours of cold ischemia (control group I). The right lungs were also placed in cold storage but were perfused continuously for three hours with low-potassium UW solution at 10 degrees C (group II). In the second phase, ten rabbits underwent a right lung auto-transplant. Lungs were conserved using two techniques. Histoenzymatic and pathological tests were performed: lung function was evaluated. In the first phase the histopathological examination carried out at the end of storage revealed fewer ischemic alterations in the second group compared to the first. In the second phase a significant hypoxia was observed in group I when both lungs and the right lung only were perfused. The histopathological examination revealed ischaemia/reperfusion lesions in both groups though mainly in group I and a good level of ATPase activity in group II though these results were not significant. Cold flushing of the pulmonary artery and continuous perfusion during static hypothermic storage appears to guarantee a better partial arterial pressure of oxygen in this model of auto-transplant compared to the classical cold storage method.

The relationships among ultrastructural angiogenic features, Na+ K+, Ca+2, Mg+2 ATP-ase activities and SOD concentration in the microvasculature of intracranial meningiomas and glial tumors

The purpose of this study was to investigate the relationship among ultrastructural angiogenic features, adenosine-5′-triphosphatase (ATP-ase) activities and superoxide dismutase (SOD) concentration in the microvasculature of intracranial meningiomas and glial tumors. We examined 20 tumor materials from 20 adult patients with intracranial meningioma or glial tumor who underwent selective surgery, dividing them into two groups based on the type of the tumors. Group I consisted of 10 meningioma-materials, and Group II of 10 glial tumor-materials. Na+ -K+, Mg+2 and Ca+2 ATP-ase activities in Group I were significantly higher than those in Group II (p < 0.01). The SOD activity in Group I was significantly lower than that in Group II (p < 0.01). According to electron microscopic findings, vascular endothelial proliferation and ultrastructural cytoplasmic changes in the glial tumors were more prominent than those in the meningiomas. Our results show that there is a meaningful correlation among an increased endothelial proliferation, a decreased ATP-ase level and an increased SOD activity in the meningiomas and glial tumors. [Neurol Res 2002; 24: 286-290]

Assessment of myocardial subcellular function after 24 hours of in vitro preservation and transplantation

The excitation-contraction coupling system of canine myocardium was studied after 24 hours of preservation (continuous hypothermic perfusion) and then compared to the excitation-contraction coupling system of hearts preserved after 3 hours in 4° C isotonic saline. Heterotopic transplantation was then performed to assess the effects of reperfusion after in vitro preservation. Sarcoplasmic reticulum (SR) calcium uptake and adenosine triphosphatase (ATPase) activity and myofibrillar ATPase activity were studied. Study hearts were divided into four groups and compared to normal canine controls (n = 4): Group A (n = 4), 24 hours of preservation with hypothermia and continuous nonpulsatile perfusion; Group B (n = 4), 24 hours of preservation followed by successful heterotopic transplantation for 24 hours; Group C (n = 4), 3 hours of preservation in 4° C isotonic saline; and Group D (n = 4), 3 hours of hypothermic saline preservation followed by heterotopic cardiac transplantation. SR Ca 2+ -stimulated, Mg 2+ -dependent ATPase activity was not significantly different from control values in any of the four experimental groups. SR calcium uptake from Group A was well preserved, whereas that from Group C was significantly depressed. Following transplantation both Groups B and D demonstrated depressed calcium uptake. The coupling ratio (μmoles Ca 2+ transported/μmole ATP hydrolyzed) was depressed in all groups except A. Contractile protein function measured as myofibrillar pCa-ATPase curves demonstrated a depression of maximal ATPase activity in Groups C and D but not in Groups A and B. Double reciprocal plots of myofibrillar ATPase activity revealed an increase in K m for all groups, with Group B demonstrating the least depression of enzyme affinity. It is concluded that myocardial preservation in 4° C saline for only three hours results in a significant degree of ischemic / reperfusion injury to the excitation-contraction coupling system. In contrast, the intact heart can be maintained for 24 hours by continuous, nonpulsatile, hypothermic perfusion with a minimum of ischemic/reperfusion injury to the excitation-contraction coupling system.

Cardiac actomyosin ATPase activity after prolonged physical conditioning and deconditioning.

Cardiac actomyosin ATPase was increased by making rats swim 150 min/day, 5 days/wk for 8 wk. Changes in Ca2+ -stimulated ATPase activity were then studied in these conditioned rats and in similarly conditioned animals in which swimming was subsequently discontinued (group A), reduced to 45 min/day (group B), or continued at the original level for an additional 8 wk (group C). After the 8-wk initial program actomyosin ATPase activity averaged 22% higher in hearts of conditioned rats than in hearts of sedentary controls (P is less than 0.001). In group A, actomyosin ATPase activity declined rapidly and reached the level found in sedentary controls by the 13th day. In group B, actomyosin ATPase activity declined to the control level by the 30th day. At the end of 16 wk the percent increase in actomyosin ATPase activity in group C over that in hearts of sedentary animals was approximately the same as after 8 wk. These results demonstrate that elevation in cardiac actomyosin ATPase caused by moderate physical training in rats is not maintained if the training program is decreased or discontinued. The training program must be continued at or near the initial level if the increases in cardiac actomyosin ATPase are to be sustained.