RESUMEN
Intracellular calcium overload is a key factor for myocardial ischemia reperfusion injury (IR). However, there was no report for interstitial calcium concentration dynamics. We investigated the interstitial calcium dynamics in rat myocardial IR model in vivo. A microdialysis system was involved, and the time delay of the system and recovery time was introduced and tested with a fluids switching method. Twelve SD rats were divided into IR or control group. Myocardial IR was induced by ligating (20 min) then releasing (60 min) the suture underlying left anterior descending branch. Mycrodialyisis probe was implanted into the left ventricular myocardium perfusion area for occlusion. Dialysate samples were collected every 10 min. Dialysate calcium concentration was detected with an atomic absorption spectrophotometer. Recovery time for the microdialysis system was 20 min, and recovery rate was 16%. Dialysate calcium concentration showed no changes during ischemia, descended immediately after reperfusion, reached the lowest level (67% of baseline value) 20 min after reperfusion, then escalated slowly. Recovery time was an important parameter for mycrodialysis technique, and it should not be neglected and needed to be tested. Our data suggest that interstitial calcium concentration in rats with myocardial IR in vivo kept steady in ischemia, descended rapidly at the initial reperfusion, then rebounded slowly. In conclusion, we introduced the concept of recovery time for microdialysis and provided a simple testing method.
Asunto(s)
Animales , Masculino , Ratas , Calcio , Metabolismo , Soluciones para Diálisis , Metabolismo , Espacio Intracelular , Metabolismo , Cinética , Microdiálisis , Métodos , Daño por Reperfusión Miocárdica , Metabolismo , Ratas Sprague-Dawley , Espectrofotometría Atómica , Factores de TiempoRESUMEN
Intracellular calcium overload is a key factor for myocardial ischemia reperfusion injury (IR). However, there was no report for interstitial calcium concentration dynamics. We investigated the interstitial calcium dynamics in rat myocardial IR model in vivo. A microdialysis system was involved, and the time delay of the system and recovery time was introduced and tested with a fluids switching method. Twelve SD rats were divided into IR or control group. Myocardial IR was induced by ligating (20 min) then releasing (60 min) the suture underlying left anterior descending branch. Mycrodialyisis probe was implanted into the left ventricular myocardium perfusion area for occlusion. Dialysate samples were collected every 10 min. Dialysate calcium concentration was detected with an atomic absorption spectrophotometer. Recovery time for the microdialysis system was 20 min, and recovery rate was 16%. Dialysate calcium concentration showed no changes during ischemia, descended immediately after reperfusion, reached the lowest level (67% of baseline value) 20 min after reperfusion, then escalated slowly. Recovery time was an important parameter for mycrodialysis technique, and it should not be neglected and needed to be tested. Our data suggest that interstitial calcium concentration in rats with myocardial IR in vivo kept steady in ischemia, descended rapidly at the initial reperfusion, then rebounded slowly. In conclusion, we introduced the concept of recovery time for microdialysis and provided a simple testing method.
RESUMEN
<p><b>OBJECTIVE</b>To study the reasonable dosage for paraplatin according to different dosage calculations.</p><p><b>METHODS</b>A prospective, randomized, single-blinded study on 54 patients with advanced non-small-cell lung cancer (NSCLC) treated with paraplatin was conducted. Patients were divided to 2 groups. In group A, paraplatin dosage was calculated according to patients' body surface, and in group B, it was calculated according to the area under the curve (AUS). Hematological toxicity, response rate and survival rate in the two groups of patients were compared.</p><p><b>RESULTS</b>Neutropenia in group A and group B was seen in 77.8% and 37.0% (P < 0.05), and thrombocytopenia in 18.5% and 3.7% (P > 0.05) of patients, respectively. Hemoglobin decrease was seen in 48.2% of patients in both groups. The average quantity of paraplatin given in one cycle of treatment was 535.93 +/- 106.71 mg and 398.52 +/- 71.72 mg (P < 0.01) respectively. The average time interval between treatment cycles was 27.04 +/- 5.30 d and 22.85 +/- 2.80 d (P < 0.05). The response rate and survival rate of patients in group A and B were 22.2% versus 48.2% (P < 0.05), and 40.7% versus 44.4% (P > 0.05) respectively, but the median survival time was identical (12 months) in the two groups.</p><p><b>CONCLUSION</b>NSCLC patients given paraplatin with dosages calculated on the basis of AUC have higher response rate and less severe hematological toxicity than those given paraplatin with dosages on the basis of body surface. However, the median survival time and survival rate have no statistical differences between the two groups of patients.</p>