Longitudinal MRI Evaluation of Ischemic Stroke in the Basal Ganglia of a Rhesus Macaque (Macaca mulatta) with Seizures.

An adult rhesus macaque developed seizures after the induction of ischemic stroke. Initially, on the day of surgery, a focal ischemic lesion was present exclusively in the right caudate nucleus. By 48 h after stroke induction, the lesion had extended into the putamen, when a seizure was observed. Our report highlights the temporal changes in infarction of unilateral basal ganglia after acute stroke and the accompanying clinical symptoms. This unusual case may provide additional information regarding the involvement of the basal ganglia in seizures, given that prior case reports and studies usually have not described the temporal and spatial evolution of the lesion before clinical symptoms emerge.

Accuracy of Human and Veterinary Point-of-Care Glucometers for Use in Rhesus Macaques (Macaca mulatta), Sooty Mangabeys (Cercocebus atys), and Chimpanzees (Pan troglodytes).

Handheld, point-of-care glucometers are commonly used in NHP for clinical and research purposes, but whether these devices are appropriate for use in NHP is unknown. Other animal studies indicate that glucometers should be species-specific, given differences in glucose distribution between RBC and plasma; in addition, Hct and sampling site (venous compared with capillary) influence glucometer readings. Therefore, we compared the accuracy of 2 human and 2 veterinary glucometers at various Hct ranges in rhesus macaques (Macaca mulatta), sooty mangabeys (Cercocebus atys), and chimpanzees (Pan troglodytes) with that of standard laboratory glucose analysis. Subsequent analyses assessed the effect of hypoglycemia, hyperglycemia, and sampling site on glucometer accuracy. The veterinary glucometers overestimated blood glucose (BG) values in all species by 26 to 75 mg/dL. The mean difference between the human glucometers and the laboratory analyzer was 7 mg/dL or less in all species. The human glucometers overestimated BG in hypoglycemic mangabeys by 4 mg/dL and underestimated BG in hyperglycemic mangabeys by 11 mg/dL; similar patterns occurred in rhesus macaques. Hct did not affect glucometer accuracy, but all samples were within the range at which glucometers generally are accurate in humans. BG values were significantly lower in venous than capillary samples. The current findings show that veterinary glucometers intended for companion-animal species are inappropriate for use in the studied NHP species, whereas the human glucometers showed clinically acceptable accuracy in all 3 species. Finally, potential differences between venous and capillary BG values should be considered when comparing and evaluating results.

Effects of extended-release injectable naltrexone on self-injurious behavior in rhesus macaques (Macaca mulatta).

Self-injurious behavior (SIB) is a spontaneous behavior that threatens the health and wellbeing of multiple species. In humans, the opioid antagonist naltrexone hydrochloride has been used successfully to modulate the endogenous opioid system and reduce the occurrence of SIB. This study is the first to assess the efficacy of extended-release naltrexone in the pharmacologic treatment of SIB in rhesus macaques (Macaca mulatta). In an acute pharmacokinetic study of 4 macaques, we determined the mean naltrexone plasma concentration was maintained above the therapeutic level (2 ng/mL) after administration of a single dose (20 mg/kg) of 28-d extended-release naltrexone throughout the release period. For a subsequent treatment study, we selected 8 singly housed macaques known to engage in SIB. The study comprised a 4-wk baseline phase; an 8-wk treatment phase, during which each macaque received 2 doses of extended-release naltrexone 28 d apart; and a 4-wk posttreatment phase. Plasma samples were collected and analyzed weekly for naltrexone concentrations throughout the treatment and posttreatment phases. In addition, total of 6 h of video was analyzed per animal per phase of the study. Compared with baseline phases, both the frequency and the percentage of time spent displaying SIB decreased during the treatment phase, and the percentage of time remained decreased during the posttreatment phase. In contrast, extended-release naltrexone did not alter the expression of other abnormal, anxiety-related, or agonistic behaviors nor were levels of inactivity affected. The present study supports the use of naltrexone in the treatment of SIB in rhesus macaques.

Double-outlet right ventricle and double septal defects in a Rhesus macaque (Macaca mulatta).

A 6-year-old male India-origin Rhesus macaque (Macaca mulatta) presented with thin body condition and muscular atrophy. Thoracic auscultation revealed a grade VI/VI pansystolic murmur bilaterally. Radiographs showed cardiomegaly with significant left atrial and biventricular enlargement, a dilated pulmonary artery, and hepatomegaly. Electrocardiogram revealed a normal sinus rhythm interspersed with ventricular bigeminy. Hematology showed mild polycythemia and prerenal azotemia. Necropsy demonstrated double-outlet right ventricle with a large subaortic ventricular septal defect, subpulmonary stenosis, small atrial septal defect, and right ventricular hypertrophy. The major histological finding was severe chronic passive hepatic congestion. Double-outlet right ventricle is a rare congenital heart disease, both in human beings and animals.