Performance evaluation of the Sysmex XN-1000V in side-by-side comparison with the Siemens ADVIA 120 and manual methods for healthy CD Sprague-Dawley rats and CD-1 mice.

BACKGROUND: The Sysmex XN-1000V automated hematology analyzer with multispecies software was released in June 2017 for use in research laboratories. Laser light, impedance, fluorescent staining, and fluorescent flow cytometry are used to analyze whole blood for CBC, reticulocyte counts, and WBC counts, including a 5-part differential leukocyte analysis. OBJECTIVES: A side-by-side comparison of the Sysmex XN-1000V with the Siemens ADVIA 120 in analyzing blood from healthy mice and rats will provide insight into the performance of the new analyzer and its capabilities for use in drug development studies. Method correlation analyses on normal mouse and rat hematology data collected with both analyzers and manual reference methods will help determine the reliability of the data produced using the Sysmex XN-1000V analyzer. METHODS: Whole blood samples collected in K2 EDTA from healthy CD-1 mice and CD Sprague-Dawley rats were analyzed in parallel with the XN-1000V and ADVIA 120 analyzers. Male and female mice, approximately 6-9 weeks old, and male and female rats, approximately 7-9 weeks old, were included in this study. Manual reference methods for WBC differential leukocyte analysis and packed cell volume (PCV) measurements were also performed. EP Evaluator version 11.2 (Data Innovations LLC, South Burlington, VT, USA) was used for method comparison statistical analysis. RESULTS: Most hematologic parameters for naïve mice and rats achieved correlation in the fair to excellent range, with the majority showing very good to excellent correlation with low biases (<11.0%) for cohorts analyzed separately and when cohort data were combined. CONCLUSIONS: The Sysmex XN-1000V Hematology Analyzer provided comparable results to those obtained from the Siemens ADVIA 120. We found the Sysmex XN-1000V Hematology Analyzer to be acceptable for use in drug development studies for rats and mice.

Longitudinal studies of cardiac troponin I concentrations in serum from male cynomolgus monkeys: resting values and effects of oral and intravenous dosing on biologic variability.

BACKGROUND: There is a paucity of information regarding cardiac troponin (cTn) concentrations in peripheral blood of nonhuman primates (NHP). Even less is known regarding cTn concentrations in monkeys that are restrained for oral or intravenous (iv) dosing. OBJECTIVES: The objectives of these studies were to (1) determine cardiac troponin I (cTnI) concentration in resting Cynomolgus monkeys and investigate biologic variability in cTnI concentration over time, (2) determine cTnI changes in restrained monkeys given sham oral dosing, and (3) determine cTnI changes in restrained NHP given a sham intravenous dosing. METHODS: The Research Use Only Erenna cTnI ultrasensitive immunoassay based on single molecule counting technology was used to determine serum cTnI concentration in longitudinal studies of male Cynomolgus monkeys at rest, and after sham oral and intravenous dosing. Animals were catheterized prestudy, and blood samples were collected by an automated sampling device to limit disturbance of the animals during studies. RESULTS: In resting monkeys cTnI concentrations were relatively low and constant and ranged from 0.2 to 9.6 pg/mL (mean = 2.5 pg/mL), with minimal variability during a 24-hour period. Animals given sham oral dosing also had low cTnI concentration with little variability similar to the resting values. Several animals restrained for intravenous dosing had a small transient increase in cTnI concentration (~5-25 pg/mL) that resolved quickly within one to 3 hours postinjection. CONCLUSIONS: Results of this longitudinal study provide information that may be important in differentiating effects of animal handling from those associated with compound-related effects in preclinical toxicology studies of drugs in development.

Deciphering ADME genetic data using an automated haplotype approach.

OBJECTIVE: To investigate the utility of statistical tools in translating Affymetrix Drug Metabolizing Enzyme and Transporter (DMET) Assay single-nucleotide polymorphisms (SNPs) into common consensus star alleles. METHODS: DMET SNP data from clinical trials in different ethnicities were pooled for analyses. Three different statistical methods, PHASE, Bayesian, and expectation-maximization (EM), were first assessed by comparing the consistency of calling CYP2D6 alleles among 1108 Asians and 55 Caucasians. Subsequently, the performance of EM in deriving haplotype calls was evaluated against the Affymetrix Translation Table for CYPs 2B6, 2C19, 2C9, and 3A4/5 in 582 Asians, 296 Caucasians, and 369 Africans. Selected DNA samples were sequenced to verify the EM-predicted haplotype calls. RESULTS: PHASE, Bayesian, and EM methods showed a similar CYP2D6 star allele call rate. The EM method, with a 0.99 posterior probability cutoff, was chosen for further evaluation because of its low false-positive call rate. Haplotype calls obtained with the EM method were consistent with the Affymetrix Translation Table more than 95% of the time for all five CYPs, except for the CYP2B6 calls in the African descents (83%). In addition, the EM method was superior to the Translation Table-only approach in resolving complex haplotype patterns, identifying novel haplotypes in CYP2B6 and CYP3A5, and determining genotype calls in the presence of missing SNP data. CONCLUSION: A statistical method such as EM could be used to augment the translation of DMET assay SNP data into star alleles, especially for complex genes, to facilitate full utilization and interpretation of clinical pharmacogenetics data.

Refinement of the dosage and dosing schedule of ketoprofen for postoperative analgesia in Sprague-Dawley rats.

Though ketoprofen is commonly used in rodent surgical procedures, an optimal dosing regimen has not yet been established. The authors sought to refine ketoprofen dosage requirements in rats and to determine whether one or two doses were needed. In one experiment they compared the effects of one preoperative dose of ketoprofen with those of two perioperative doses (3 mg per kg body weight). In a second experiment they compared the effects of two different dosages of ketoprofen (3 or 5 mg per kg body weight). Results show that all regimens tested were similarly effective in curbing post-surgical weight loss and reduction in food and water consumption; therefore, a single dose of 3 mg per kg body weight was the most efficient.

Duration of clinical effects and absence of referred hyperalgesia after femoral vein cannulation in rats.

The goal of this study was to assess the duration of pain-related clinical effects and referred hyperalgesia after surgery in rats. Isoflurane anesthesia with or without femoral vein cannulation was performed (n = 6 per group). Body weight and food and water consumption were monitored daily for 48 h, and tail-flick latency was measured twice daily for 24 h after surgery. Water consumption at 24 h after surgery was significantly decreased in the surgical group compared with baseline values and those of the anesthesia group. Body weight change and food consumption showed nonsignificant decreases compared with baseline in both groups 24 h after the procedure. There was a trend toward decreased food consumption after surgery compared with that for the anesthesia-alone group. Tail-flick latency was nonsignificantly decreased the afternoon after surgery compared with baseline values or that after anesthesia alone. Tail-flick latency was similar to baseline and between groups 24 h after surgery. All parameters were similar between groups and compared with baseline by 48 h after surgery. Our results show some changes in postsurgical pain-related parameters only during the initial 24-h period after femoral cannulation surgery, but only the change in water consumption was significant. Although this study involved only a small number of animals, our findings suggest that femoral vein cannulation produces a less painful stimulus than that seen in studies assessing these parameters after abdominal surgery. Hyperalgesia from a distant painful stimulus could not be measured in this model by using the tail-flick assay.

Duration of effects on clinical parameters and referred hyperalgesia in rats after abdominal surgery and multiple doses of analgesic.

This study evaluated the duration of clinical effects and referred hyperalgesia in rats (n = 10 per group) undergo ing abdominal surgery with analgesics (ketoprofen at 3 mg/kg and buprenorphine at 0.01 or 0.1 mg/kg) administered intramuscularly twice daily for 72 h beginning prior to surgery; no-surgery and no-analgesia control groups were included. Food and water consumption and body weight were monitored daily. As a measure of referred hyperalgesia, tail-flick latency was measured daily, before and 4 h after analgesia administration. Compared with those of the no-surgery controls, significant decreases in food consumption and body weight occurred 24 h after surgery without analgesics. There were nonsignificant reductions in these effects by analgesics, but the benefits were not significantly different than those of saline. These parameters continued to be decreased with variable significance in the buprenorphine groups at 48 and 72 h after surgery. In both buprenorphine-treated groups, water consumption was significantly increased at 24 h after surgery but not at 48 or 72 h. Tail-flick latency was not significantly different between the no-surgery and no-analgesia groups but was significantly increased 4 h after high-dose buprenorphine administration and declined nonsignificantly over time in the other groups. We conclude that painful effects from surgery are present primarily during the first 24 h after surgery. The analgesic regimens tested did not completely reduce these effects. Buprenorphine was associated with adverse effects for as long as 72 h after surgery. Referred hyperalgesia from this abdominal surgery could not be measured using the tail-flick assay.