The aim of this study was to determine if 6-month acclimation would enable accurate evaluation of hematological, biochemical data, and ECG recorded under restraint for conscious rhesus monkeys of both sexes. Periodic evaluation of these parameters was made during the 6-month period of acclimation. The platelet count, alkaline phosphatase, glucose, and sodium levels significantly decreased, whereas creatinine increased, compared with pre-acclimation values. The heart rate was significantly reduced compared with pre-acclimation values. QT-RR relation followed the square root regression function, which means modification of Bazett's QTc formula can be applied even if the ECG is recorded under restraint. In conclusion, 6-month acclimation was effective for stabilizing the blood data and for allowing accurate evaluation of the ECG even under restraint. Current results show that an acclimation period at least 3 months may be necessary prior to using rhesus monkeys for chronic studies.

No abstract

Alkaline phosphatases (EC 3.1.3.1) (APs) are dimeric metalloenzymes that catalyze the hydrolysis of phosphate monoesters into inorganic phosphate [1] To understand the differences between the rat intestinal alkaline phosphatase isozymes rIAP-I and rIAP-II, we constructed structural models based on the previously determined crystal structure for human placental alkaline phosphatase (hPLAP). Our models of rIAP-I and rIAP-II displayed a typical a ⁄ b topology, but the crown domain of rIAP-I contained an additional b-sheet, while the embracing arm region of rIAP-II lacked the a-helix, when each model was compared to hPLAP. The representations of surface potential in the rIAPs were predominantly positive at the base of the active site. The coordinated metal at the active site was predicted to be a zinc triad in rIAP-I, whereas the typical combination of two zinc atoms and one magnesium atom was proposed for rIAP-II. Using metal-depleted extracts from rat duodenum or jejunum and hPLAP, we performed enzyme assays under restricted metal conditions. With the duodenal and jejunal extract, but not with hPLAP, enzyme activity was restored by the addition of zinc, whereas in nonchelated extracts, the addition of zinc inhibited duodenal IAP and hPLAP, but not jejunal IAP. Western blotting revealed that nearly all of the rIAP in the jejunum extracts was rIAP-I, whereas in duodenum the percentage of rIAP-I (55%) correlated with the degree of AP activation (60% relative to that seen with jejunal extracts). These data are consistent with the presence of a triad of zinc atoms at the active site of rIAP-I, but not rIAP-II or hPLAP. Although no differences in amino acid alignment in the vicinity of metal-binding site 3 were predicted between the rIAPs and hPLAP, the His153 residue of both rIAPs was closer to the metal position than that in hPLAP. Between the rIAPs, a difference was observed at amino acid position 317 that is indirectly related to the coordination of the metal at metal-binding site 3 and water molecules. These findings suggest that the side-chain position of His153, and the alignment of Q317, might be the major determinants for activation of the zinc triad in rIAP-I.Abbreviations AP, alkaline phosphatase; BAC, base of the active site cleft; CB, carbonate-bicarbonate; DM, double mutant; ECAP, Escherichia coli alkaline phosphatase; GCAP, germ cell-type alkaline phosphatase; hPLAP, human placental alkaline phosphatase; IAP, intestinal alkaline phosphatase; M1, metal-binding site 1; M2, metal-binding site 2; M3, metal-binding site 3; PLAP, placental alkaline phosphatase; rIAP, rat intestinal alkaline phosphatase; SAP, shrimp alkaline phosphatase; TNAP, tissue-nonspecific alkaline phosphatase.

The aim of this study was to determine the time required for the cardiovascular system of a conscious cynomolgus monkey, in which a telemetry had been implanted, to recover from excitement induced by handling stress. With enforcement of guidelines regarding safety pharmacological studies, cardiovascular studies in primates have become more important. However, as macaque monkeys are promptly excited under experimental procedures, it is often difficult to evaluate the drug effects on the cardiovascular system. Therefore, we tested monkey chair restraint and intravenous injection of saline. After monkey chair restraint and intravenous injection, approximately 30 minutes were required for recovery of both heart rate and blood pressure to their pre-treatment level; however, ECG parameters such as PR, QRS interval, and QTc did not drastically change. Based on our current results and with sufficient consideration of autonomic nervous effects, accurate evaluation of drug effects on the cardiovascular system should now be possible.