Determination of Fetal Age by Ultrasonography in St. Kitts Green Monkeys

Application of ultrasonographic human estimated foetal weight formulas to cynomolgus monkeys (Macaca fascicularis) at 129-132 days of gestation: A comparative study of estimated and actual birthweight

BACKGROUND

Cynomolgus monkeys (Macaca fascicularis) are essential in biomedical research, including reproductive studies. However, the application of human estimated foetal weight (EFW) formulas using ultrasonography (USG) in these non-human primates is not well established.

OBJECTIVES

This study aims to evaluate the applicability of human EFW formulas for estimating foetal weight in cynomolgus monkeys at approximately 130 days of gestation.

METHODS

Our study involved nine pregnant cynomolgus monkeys. We measured foetal parameters, including biparietal diameter, head circumference, abdominal circumference and femur length using USG. The EFW was calculated using 11 human EFW formulas. The actual birthweight (ABW) was recorded following Cesarean section, the day after the EFW calculation. For comparing EFW and ABW, we employed statistical methods such as mean absolute percentage error (APE) and Bland-Altman analysis.

RESULTS

The ABW ranged between 200.36 and 291.33 g. Among the 11 formulas, the Combs formula showed the lowest APE (4.3%) and highest correlation with ABW (p < 0.001). Notably, EFW and ABW differences for the Combs formula were ≤5% in 66.7% and ≤10% in 100% of cases. The Bland-Altman analysis supported these results, showing that all cases fell within the limits of agreement.

CONCLUSIONS

The Combs formula is applicable for estimating the weight of cynomolgus monkey fetuses with USG at approximately 130 days of gestation. Our observations suggest that the Combs formula can be applied in the prenatal care and biomedical research of this species.

Parkinsonian monkeys with prior levodopa-induced dyskinesias followed by fetal dopamine precursor grafts do not display graft-induced dyskinesias

Clinical trials testing the hypothesis that fetal dopamine grafts would provide antiparkinsonian benefit in patients who had already developed side effects from their long-term use of L-dopa revealed, in some cases, the presence of dyskinesias even in the absence of L-dopa. The form, intensity, and frequency of these dyskinesias were quite variable, but their manifestation slowed the clinical development of cell replacement therapies. Rodent models of graft-induced dyskinesias (GIDs) have been proposed, but their accuracy in modeling GIDs has been questioned because they usually require amphetamine for their presentation. The present study attempted to model GIDs in parkinsonian monkeys and, for the first time, to test the effect of grafts on previously dyskinetic monkeys. Toward this end, monkeys were rendered parkinsonian with n-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and dyskinetic with levodopa. They then received intraputamenal grafts of fetal dopaminergic cells, control cerebellar cells, or vehicle bilaterally and were studied for 18 months. Dopaminergic cells were grafted in a manner designed to produce either "hot spot" or "widespread" striatal innervation. Although levodopa-induced dyskinesias could be elicited postoperatively, GIDs were never observed in any animal at any time after grafting. Grafted monkeys were also challenged with levodopa but did not show any greater responses to these challenges than before grafting. These studies support the development of future dopamine neuron cell transplantation therapy-based approaches, indicating that in relevant primate models with appropriate cell preparation methodology, with successful graft survival and putamenal dopamine innervation, there is no evidence of graft-induced dyskinesias. J. Comp. Neurol. 525:498-512, 2017. © 2016 Wiley Periodicals, Inc.

Coordinated expression of dopamine transporter and vesicular monoamine transporter in the primate striatum during development

Several addictive or neurotoxic drugs are dependent on the dopamine transporter (DAT) and/or vesicular monoamine transporter (VMAT2) to exert their detrimental effects on dopamine neurons. For example, methamphetamine and MPTP are substrates for both DAT and VMAT2, with the ratio of DAT to VMAT2 in striatum being a determinant of the degree of toxicity inflicted by these drugs on dopamine neurons. Thus, the susceptibility of dopamine neurons to agents whose pharmacology involves DAT and VMAT2 may vary during development if the ontogeny of DAT and VMAT2 differs, and this is relevant as exposure of dopamine neurons to toxic agents during development is hypothesized to underlie some neurological or psychiatric disorders. However, the relative expression of DAT and VMAT2 has not been studied in either primate or nonprimate fetal brain, and this was addressed in the present study by measuring the binding of specific radioligands of DAT and VMAT2 to striatal membranes from nonhuman primates at mid-gestation, late-gestation, and the postnatal and adult periods. Dopamine concentration was also determined in striatal tissue from the same brains. These data indicate that in striatum of primates, unlike rodents, there is a sharp increase in DAT and VMAT2 expression after mid-gestation, with adult levels being attained at the time of birth. In addition, this study demonstrated that there is a coordinated expression of DAT and VMAT2 from the time of mid-gestation to adulthood.