The present work was carried out in order to determine whether a decrease in cardiac Na+‐Ca2+ exchanger (NCX) activity observed in diabetes is caused by a reduction in NCX protein and mRNA levels and to elucidate the significance of this decrease in alterations in [Ca2+]i homeostasis in diabetic cardiomyocytes.
The NCX current was significantly reduced in ventricular myocytes freshly isolated from streptozotocin‐induced diabetic rat hearts, and its current density was about 55 % of age‐matched controls.
Diabetes resulted in a 30 % decrease in cardiac protein and mRNA levels of NCX1, a NCX isoform which is expressed at high levels in the heart.
The reduced NCX current and the decreased protein and mRNA levels of NCX1 in diabetes were prevented by insulin therapy.
Although both diastolic and peak systolic [Ca2+]i were not different between the two groups of myocytes, increasing external Ca2+ concentration to high levels greatly elevated diastolic [Ca2+]i in diabetic myocytes. Inhibition of NCX by reduction in extracellular Na+ by 50 % could produce a marked rise in diastolic [Ca2+]i in control myocytes in response to high Ca2+, as seen in diabetic myocytes. However, cyclopiazonic acid, an inhibitor of sarcoplasmic reticulum Ca2+ pump ATPase, did not modify the high Ca2+‐induced changes in diastolic [Ca2+]i in either control or diabetic myocytes.
Only in papillary muscles from diabetic rats did the addition of high Ca2+ cause a marked rise in resting tension signifying a partial contracture that was possibly due to an increase in diastolic [Ca2+]i.
In conclusion, the diminished NCX function in diabetic myocytes shown in this study results in part from the decreased levels of cardiac NCX protein and mRNA. We suggest that this impaired NCX function may play an important role in alterations in Ca2+ handling when [Ca2+]i rises to pathological levels.
We systematically elucidated the relationship between tissue factor and TFPI in post-trauma patients. Highly activated tissue factor-dependent coagulation pathway is not sufficiently prevented by the normal TFPI levels in patients with DIC. The DIC associated with thrombotic and inflammatory responses causes MODS, and leads to poor outcome in post-trauma patients.
Continuous hemodiafiltration is highly effective in removing fluconazole from circulation. We recommend fluconazole to be dosed at 500-600 mg intravenously every 12 h in patients receiving hemodiafiltration. This dosing regimen resulted in adequate trough plasma levels for systemic fungal infection.
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