Biomedical subjects
A F Tarantal
Publications and source records attributed to A F Tarantal.
Interventional ultrasound in pregnant macaques: embryonic/fetal applications.
Similarities in developmental biology between human and nonhuman primates have resulted in the use of macaque species as models in perinatal research. Studies have frequently included invasive surgical procedures or may have required "blind" injections. Several techniques have been established in human subjects using ultrasound as a guide such as cordocentesis and fetal therapy. These techniques have been applied to the nonhuman primate laboratory setting, which significantly decreases the risk of pregnancy loss due to experimental intervention.
Intrauterine insemination with ultrasound guidance in the long-tailed macaque (Macaca fascicularis).
Techniques used for the artificial insemination of macaques have primarily involved instillation of the ejaculate into the vagina or cervical canal. Intrauterine insemination has been performed previously but only as a surgical procedure. The application of ultrasound-guided techniques for this purpose provides a method for efficiently inseminating macaques in a relatively noninvasive fashion. This report describes the successful transabdominal ultrasound-guided insemination of the long-tailed macaque and the potential application of this procedure to a variety of nonhuman primate species.
In-utero transplantation of fetal liver haemopoietic stem cells in monkeys.
To evaluate the potential of in-utero transplantation of fetal haemopoietic stem cells (HSCs) for permanent engraftment as a treatment of congenital haemoglobinopathies, fetal rhesus monkeys were transplanted with HSCs derived from fetal livers. Five pregnant monkeys (60-62 days' gestation) were given an in-utero intraperitoneal injection of fetal liver cells (10(8)-10(9) cells/kg estimated fetal recipient body weight) derived from opposite sex donors at 59-68 days' gestation. Engraftment was confirmed by karyotype analysis of peripheral blood leucocytes and bone marrow; cells of donor sex were found among the recipient cells. Donor cell engraftment was apparent in four of five in-utero HSC transplant recipients at birth. Engraftment involved lymphoid (2.9-8.0% donor cells), erythroid (5.3-12.5%), and myeloid (8.5-15.4%) lineages and has persisted for up to 2 years without evidence of graft-versus-host disease.
Ultrasound-guided transfundal uterine sperm recovery from Macaca fascicularis.
Previous studies from this center have indicated that the cynomolgus macaque (Macaca fascicularis) may serve as a model for human sperm interaction with the cervix and uterus. In some macaque species, transcervical aspiration of the uterine contents carries a significant risk of disturbing the cervical milieu due to the serpentine nature of the cervix. The only alternatives have been surgical procedures such as laparotomy or laparoscopy. In this paper, we report our experience with a new technique for ultrasound-guided sampling of spermatozoa in the macaque uterus. Twenty adult female cynomolgus macaques were monitored for menses (first day of menses = day 1), and one mating per cycle was allowed on day 10, 11, or 12. In one group of ten animals, cervical mucus was sampled at 3 or 18 hr postcoitus (pc) and ultrasound-guided uterine aspiration was performed at 24 hours pc. In a second group of ten monkeys, uterine aspiration was at six hr pc and sperm numbers and motility were counted in the uterine fluid. Uterine fluid was obtained from fourteen of twenty monkeys. Pregnancy occurred in ten of the twenty experimental cycles. Ultrasound-guided uterine aspiration appears to be a reliable method for the evaluation of sperm transport in female macaques. The correlations between uterine sperm recovery and cervical mucus sperm populations are discussed. The high conception rate in treatment cycles indicates that this procedure can be performed without apparent risk to pregnancy.
Embryotoxicity studies of norfloxacin in cynomolgus monkeys: I. Teratology studies and norfloxacin plasma concentration in pregnant and nonpregnant monkeys.
Norfloxacin, a new orally active antibiotic, was investigated in cynomolgus monkeys for potential developmental toxicity. Fifty-seven monkeys were administered a control vehicle or norfloxacin by nasogastric gavage during the major period of organogenesis on gestational days (GD) 21 through 50 at doses of 0, 50, 100, 150, or 200/300 mg/kg/day. There was no evidence of teratogenicity at any dose level. Maternotoxicity and a significant increase in embryolethality occurred following doses of 200/300 mg/kg/day. The maternotoxicity was not expected based on range-finding studies in nonpregnant female monkeys, which showed no signs of toxicity in doses up to 500 mg/kg/day. Additional studies were conducted to determine if norfloxacin caused similar toxicity later in gestation. Forty-six pregnant monkeys were dosed with a control vehicle or 200 mg/kg/day norfloxacin for one of three 10-day periods on GD 36-45, 71-80, or 111-120. There were no maternotoxic, embryotoxic, or fetotoxic effects observed. Plasma concentrations of norfloxacin in five cynomolgus monkeys following 50 and 200 mg/kg oral doses were not dose-proportionate. However, at a given dose, administered in cross-over fashion, plasma concentrations of norfloxacin were higher in nonpregnant females (approximately 20-40%) than during pregnancy when the same subject was compared. At the no-observed-effect dose for maternal and embryotoxicity (50 mg/kg), peak plasma concentrations of norfloxacin in pregnant cynomolgus monkeys are approximately threefold higher than those observed in human volunteers receiving norfloxacin at the maximum recommended therapeutic dose of 400 mg (5.7 mg/kg based on 70 kg body weight) twice per day.
Evaluation of the bioeffects of prenatal ultrasound exposure in the cynomolgus macaque (Macaca fascicularis): I. Neonatal/infant observations.
The frequency of use of ultrasonography for evaluating the developing embryo/fetus has continued to rise although the possible risks from exposure still remain uncertain. The cynomolgus macaque (Macaca fascicularis) is currently being used in our laboratory as a model to assess these risks. In utero exposure was performed utilizing a commercial real-time mechanical sector scanner with a 7.5 MHz scanhead (ATL, MK 600). Maximum acoustic power output for this unit is as follows: I(SPTA) = 12.0 mW/cm2, I(SPPA) = 98 W/cm2, and Im = 137 W/cm2. Animals exposed to ultrasound (N = 16) were scanned five times weekly on gestational days (GD) 21-35 +/- 2 for 10 minutes/exam (m/e), three times weekly on GD 36-60 +/- 2 for 10 m/e, and once weekly on GD 61-150 +/- 2 for 20 m/e. Controls (N = 14) were "scanned" with the unit placed on standby. Assessment of simian Apgar scores at 1, 5, and 10 minutes of life revealed higher scores for treated animals at 10 minutes (P less than or equal to 0.045); greater scores in muscle tone (P less than or equal to 0.013) and color (P less than or equal to 0.016) were observed. Evaluation of morphometrics at birth including weight, biparietal diameter, occipitofrontal diameter, head circumference, hand and foot lengths, humerus and femur lengths, arm circumference, chest circumference, tail length, skinfold thickness, and crown-rump length (CRL) indicated a significant reduction in only two parameters, birth weight (P less than or equal to 0.027) and CRL (P less than or equal to 0.033). Hematologic analysis at 2 +/- 1, 9 +/- 1, and 16 +/- 1 days of life revealed a significant difference in white blood cell counts (WBCs). Treated animals displayed lower WBCs with reductions in numbers of segmented neutrophils and monocytes at all ages observed. Hematologic differences were not significant by 5-6 months of age. No abortions, gross malformations, or stillbirths were observed in the exposed animals.
Evaluation of the bioeffects of prenatal ultrasound exposure in the cynomolgus macaque (Macaca fascicularis): II. Growth and behavior during the first year.
The extensive use of ultrasonography for the prenatal assessment of growth and development continues to present questions regarding biological effects. We are currently evaluating a nonhuman primate model (Macaca fascicularis) exposed to ultrasound from gestational day (GD) 21 to 152 +/- 2. Exposures were performed with a commercial real-time sector scanner (ATL, MK 600); animals were scanned five times weekly on GD 21-35 +/- 2, three times weekly on GD 36-60 +/- 2, and once weekly on GD 61-150 +/- 2. The length of exposure was approximately the same as human exposure (GD 21-60 +/- 2 = 10 min/exam and GD 61-150 +/- 2 = 20 min/exam) although the frequency of the examinations was considerably greater. Initial reports indicated differences between control and treated animals including lower birth weight, higher simian Apgar scores, and changes in select hematologic parameters. Follow-up evaluations of growth during the first year included measurements of body weight, hand and foot lengths, humerus and femur lengths, biparietal and occipitofrontal diameters, head circumference, arm circumference, chest circumference, skinfold thickness, and crown-rump length. Results indicated a significant reduction in body weight in treated animals during the first three months, with nonsignificant differences during the following nine months. Hematologic analysis including complete blood counts (CBC) and clinical biochemistry at 6, 9, and 12 months of age were not significantly different. A series of behavioral evaluations including a neurobehavioral test battery (NBT) and tests assessing motor and cognitive skills were included. The NBT revealed increased muscle tone in treated animals at one, two, and four days. In an observation cage (week 1-14) more quiet activities were displayed by treated animals. Group differences in performance of motor and cognitive tasks were observed and may be attributable to agitation and difficulties in adjusting to test environments. There were no group differences observed in discrimination learning. When considering the possible implications to the human population, it is important to consider the amount of exposure these animals received, and the fact that most of the effects observed appeared to be transitory. Although human epidemiological studies have not revealed any significant bioeffects, the "prudent use" of diagnostic ultrasound should still be kept in mind. This is especially significant with the current rise in the use of endovaginal scanning and pulsed Doppler.
The effect of the anti-progestin RU 486 on early pregnancy in the long-tailed macaque (Macaca fascicularis).
The efficacy of various doses of RU 486 in terminating pregnancy before and after the luteal-placental shift (LPS) in the long-tailed macaque (Macaca fascicularis) was assessed through sonographic examination and measurements of steroid hormones and their metabolites. Intramuscular injection of 1.0, 2.5, 12.5, or 25.0 mg/kg was administered either from gestational day (GD) 15-18 (Group 1; N = 11) or GD 23-26 (Group 2; N = 9). The timing of treatment was determined by the detection of the preovulatory estrogen peak via daily urinary estrone conjugate (E1C) measurements. In Group 1, a 90.9% pregnancy loss was observed (10/11); seven animals aborted during GD 15-20, two animals indicated early embryonic death with retained gestational sacs, one animal aborted on GD 56, and one pregnancy was maintained. In Group 2, an 88.9% pregnancy loss was observed (8/9); eight animals aborted between GD 26-29, and one pregnancy was unaffected. Hormone profiles appeared to fall secondarily to the loss of trophoblast function. These results indicate: (a) RU 486 was more effective after the LPS; and (b) the primary effect of RU 486 appeared to be at the level of the products of conception.
Characterization of prenatal growth and development in the crab-eating macaque (Macaca fascicularis) by ultrasound.
Diagnostic ultrasound is a valuable tool for the examination of various anatomical structures in vivo. Improvements in technology have increased its effectiveness and provided a noninvasive method for the in utero observation of a variety of structural and functional events. Ultrasound is utilized in our laboratory to monitor a variety of studies during embryonic and fetal development. Basic to these evaluations is the ability to assess normal growth and development. The cynomolgus, or crab-eating macaque (Macaca fascicularis), has been observed in utero by ultrasound from early gestation to term. The earliest detection of implantation is by the identification of a developing gestational sac (GS), which may be visualized on gestational day (GD) 14-15. Positive identification of the GS on GD 16-18 and appearance of the embryo, yolk sac, and cardiac motion on GD 21-25 confirms pregnancy. Once the embryo is evident, measurements of the greatest length (GL) may be used to assess normal growth or to aid in the prediction of gestational age. During the fetal period, a variety of growth parameters aid in fetal evaluation. The gender of the fetus can be accurately identified as early as GD 70-75. An assessment of viability and condition can be determined by the observation of embryonic and fetal heart rates and gross body movement.
Use of ultrasound for early pregnancy detection in the rhesus and cynomolgus macaque (Macaca mulatta and Macaca fascicularis).
Diagnostic ultrasound provides an accurate method for the detection of early pregnancy and embryonic loss in macaque species. A developing gestational sac (GS) may be observed on gestational day (GD) 14-15 with positive identification on GD 16-18. Visualization of the yolk sac, embryo, and developing heart on GD 21-25 confirms pregnancy. Continuous observations during embryogenesis provide useful information when assessing the teratogenic potential of a variety of agents.
Amniotic band syndrome in a rhesus monkey: a case report.
A rhesus monkey fetus was examined by ultrasound at 110, 111, and 113 gestational days (GD) and showed features suggestive of Amniotic Band Syndrome (ABS). These included an unusual craniofacial configuration, cortical distortion, asymmetrical hydrocephalus, a right occipital porencephalic cyst, and hydropic membranes with several free strands attached to the fetal head, neck, and scapular regions. The fetus remained fixed in the same position with the head retroflexed during each consecutive exam. A hysterotomy was performed and ABS was confirmed.
A case of nonimmune hydrops fetalis with a rare cardiac anomaly in a rhesus monkey.
A case of nonimmune hydrops fetalis in a rhesus monkey was identified by ultrasound. The 68-day fetus exhibited generalized edema, pleural effusion, and mild ascites. Intrauterine fetal demise occurred between 75 and 80 days gestation. Necropsy revealed marked anasarca and a rare cardiac anomaly characterized by aortic and left atrioventricular valve atresia, hypoplasia of the ascending aorta and arch, and absence of the left ventricle.
Intervillous blood flow in the third trimester gravid rhesus monkey (Macaca mulatta): use of sonographic contrast agent and harmonic imaging.
A properly implanted and functioning placenta is essential for the normal outcome of pregnancy. As pregnancy advances, an increasing supply of maternal blood, which reaches the intervillous space of the placenta via the spiral arteries, is necessary for continued growth and development of the fetus. Presumably, deficient blood flow to the intervillous space can lead to placental ischaemia and an unfavourable outcome, such as pre-eclampsia. In this study, we used a primate model, where echocontrast-enhanced harmonic imaging was utilized to demonstrate placental intervillous blood flow without visualization of fetal blood circulation within the chorionic villi. We propose that this technique, which requires further assessment of efficacy and safety prior to use in humans, is a potentially useful non-invasive clinical tool for assessing intervillous blood flow in the third trimester of pregnancy.