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Christian R. Abee - One of the best experts on this subject based on the ideXlab platform.
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neonatal activity and state control differences among three squirrel monkey subspecies Saimiri sciureus sciureus s Boliviensis Boliviensis and s Boliviensis peruviensis
American Journal of Primatology, 2020Co-Authors: Michele M Mulholland, Lawrence E. Williams, Christian R. AbeeAbstract:Squirrel monkeys are a long-standing biomedical model, with multiple species and subspecies housed in research facilities. Few studies have examined the developmental differences between these subspecies, which may affect research outcomes. The primate neonatal neurobehavioral assessment was completed at 2 weeks of age with 279 dam-reared squirrel monkeys (188 Saimiri Boliviensis Boliviensis, 45 S. b. peruviensis, and 46 Saimiri. sciureus sciureus). Activity, orientation to stimuli, state control, and motor maturity scores, as well as startle responses and number of vocalizations were compared across subspecies and sex using factorial analysis of covariance (ANCOVAs) controlling for birthweight. There were no differences in orientation or motor maturity scores (p > .05) among the three subspecies or between sexes; however, there were significant subspecies differences in motor activity and state control scores. Of the three subspecies, S. s. sciureus has the lowest state control and activity scores (p < .05). They also had the most exaggerated startle response/aversion to a sudden loud noise, vocalized significantly less, and were less likely to resist restraint during the assessment (p < .05). The three subspecies of squirrel monkeys did not differ in motor development and attention to external stimuli but were significantly different in state control and activity levels. Overall S. s. sciureus were less active, agitated, irritable, and easier to console compared to S. b. Boliviensis and S. b. peruviensis. This supports field research on socioecology which documented different social structure and behavior in wild populations of S. s. sciureus compared to S. b. Boliviensis and S. b. peruviensis.
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rearing condition may alter neonatal development of captive bolivian squirrel monkeys Saimiri Boliviensis Boliviensis
Developmental Psychobiology, 2020Co-Authors: Michele M Mulholland, Lawrence E. Williams, Christian R. AbeeAbstract:Nursery rearing has well-known consequences for primate species. Relative to some other primate species, research has indicated a reduced impact of nursery rearing on squirrel monkeys, particularly in terms of rates, severity, and persistence of abnormal behavior. We administered the Primate Neonatal Neurobehavioral Assessment to 29 dam-reared and 13 nursery-reared squirrel monkeys (Saimiri Boliviensis Boliviensis) at 2 and 6 weeks of age. Mixed-model ANOVAs comparing composite scores and individual assessment items across age, rearing status, and sex revealed a number of developmental differences. Dam-reared infants scored higher on all four composite measures compared to nursery-reared infants (p < .05) indicating that nursery-reared animals had slower motor development, were less active and attentive, and were more passive than their dam-reared counterparts. Consistent with infant rhesus macaques, nursery-reared squirrel monkeys showed an increased sensitivity to tactile stimulation (p < .05). Altogether, these results suggest a disruption of species-typical development when squirrel monkey infants are reared in a nursery setting, with activity, orientation, and state control areas most affected, though experimental research is needed to determine if this is a causal relationship. Contrary to previous behavioral research, there are likely developmental differences between dam-reared infant squirrel monkeys and those reared in a nursery setting.
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cellular immune responses in peripheral blood lymphocytes of giardia infected squirrel monkey Saimiri Boliviensis Boliviensis treated with fenbendazole
PLOS ONE, 2018Co-Authors: Pramod N. Nehete, Bharti P. Nehete, Sriram Chitta, Julio C. Ruiz, Henrieta Scholtzova, Lawrence E. Williams, Greg K Wilkerson, Christian R. AbeeAbstract:Cellular immune responses were tested to determine the effect of fenbendazole on the function of lymphocytes from Bolivian squirrel monkeys (Samiri Boliviensis Boliviensis). Giardia-infected squirrel monkeys were treated with commercially available fenbendazole (FBZ)-medicated monkey chow. Immune responses were compared between historical controls (Giardia naive, untreated with FBZ (control animals)) and Giardia-infected, FBZ-treated squirrel monkeys (study animals). Peripheral blood lymphocytes from study monkeys had significantly lower stimulation indices compared to control animals when cultured in vitro with concanavalin A (Con A) (p<0.0001), phytohaemagglutinin (PHA) (p<0.0001) and lipopolysaccharide (LPS) (p<0.0001). PBMCs were also analyzed for IFN-γ producing cells in response to stimulation with Con A, PHA, PWM, and LPS by the cytokine ELISPOT assay. Significantly higher responses to Con A- (p<0.0001), and PHA- (p<0.001) stimulated cultures from Giardia-infected and fenbendazole treated compared to controls. Flow cytometric analysis for expression of cell surface markers revealed a significant increase in B- and NKT-lymphocytes and significant decrease in CD14+CD16+ monocytes after FBZ treatment. Also, circulating plasma cytokines IFN-γ, TNF-α, IL-12p40, IL-1β, IL-10, IL-13, IL-1ra, IL-6 and IL-4 were significantly decreased after FBZ treatment. Comparison of hematologic parameters between controls and FBZ-treated squirrel monkeys revealed significantly lower numbers of total leukocytes, neutrophils, monocytes, and eosinophils compared to controls. However, erythrocyte indices (red cell count, hemoglobin and hematocrit were significantly higher in FBZ-treated monkeys. Our findings suggest that fenbendazole treatment may alter sensitive immune and molecular measures of inflammation. Postponing the experimental use of squirrel monkeys until at least 6 weeks after FBZ treatment should be considered.
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Cellular immune responses in peripheral blood lymphocytes of Giardia infected squirrel monkey (Saimiri Boliviensis Boliviensis) treated with Fenbendazole - Fig 1
2018Co-Authors: Pramod N. Nehete, Christian R. Abee, Gregory Wilkerson, Bharti P. Nehete, Sriram Chitta, Julio C. Ruiz, Henrieta Scholtzova, Lawrence E. Williams, John A. VanchiereAbstract:(A) Gating scheme for phenotype analyses of the various cell markers in the peripheral blood from a representative animal. The lymphocytes and monocytes were first gated based on forward scatter (FCS) versus side scatter (SSC), and then CD3+ (T cells), CD14+ (monocytes), CD3-CD16+ (NK) cells, CD3+CD16+ (NKT) cells), CD20+ (B cells), CD14+CD16+ and CD14+CD16- (monocytes) were positively identified by specific markers. The specificity of staining for the various markers was ascertained according to the isotype control antibody staining used for each pair of combination markers, as shown. (B) Effect of Fenbendazole differences in lymphocytes in squirrel monkeys. Aliquots of EDTA whole blood were stained with fluorescence-labeled antibodies to identify CD3+, CD14+, CD20+, and CD16+ cells and analyzed for cell subpopulations such as CD3+T Cells, CD20+B cells, CD16+NK cells, CD3+CD16+NKT cells and CD14 monocytes in squirrel monkeys. Monocytes (CD14) were further defined as CD14+CD16+ and CD14+CD16- monocyte. Values on the Y-axis are absolute lymphocytes cells. P values were considered statistically significant at p
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Intestinal Trichomonads (Tritrichomonas mobilensis) in the Natural Host Saimiri sciureus and Saimiri Boliviensis
2016Co-Authors: J. M. Scimeca, D. E. Culberson, Christian R. Abee, W A GardnerAbstract:Abstract. A retrospective study of cecal and colonic tissues from 28 squirrel monkeys (Saimiri sciureus and Saimiri Boliviensis) demonstrated enteric trichomonads within luminal crypts. Twenty-one of 28 (75%) had trichomonads in the mucosal epithelium either in cup-like depressions or intraepithelial vacuoles. Organisms were also beneath the superficial luminal mucosal epithelium and between the basement membrane and crypt epithelial cells. Immunoperoxidase staining also identified organisms within the lamina propria and submucosa. Additional histologic changes included mucosal ulceration, multifocal cryptitis, and focal epithelial necrosis. Most areas containing trichomonads did not have an associated inflammatory response. Trichomonads are ubiquitous flagellated protists found in most species of mammals and birds.12 Tra-ditionally, most trichomonads have been viewed as nonpathogenic commensals, but a few are important pathogens. Tritrichomonas foetus can produce bovine reproductive wastage by causing cervicitis, endome-tritis, pyometra, placentitis, and ab~rt ion.~J Tricho-monas gallinae causes mortality in turkeys, falcons, and doves, and in pigeons it invades the crop and e~ophagus.’~J ~ Trichomonas vaginalis in man is asso-ciated with vaginitis, cervicitis, and urinary tract in-fections.I8 Tritrichomonas mobilensis was isolated from rectal swabs of squirrel monkeys at the Primate Researc
Lawrence E. Williams - One of the best experts on this subject based on the ideXlab platform.
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effects of relocation on immunological and physiological measures in female squirrel monkeys Saimiri Boliviensis Boliviensis
PLOS ONE, 2021Co-Authors: Pramod N. Nehete, Bharti P. Nehete, Greg K Wilkerson, Steve J Schapiro, Lawrence E. WilliamsAbstract:In the present study, we have quantified the effects of transport, relocation and acclimate/adapt to their new surroundings on female squirrel monkey. These responses are measured in blood samples obtained from squirrel monkeys, at different time points relative to their relocation from their old home to their new home. A group of squirrel monkeys we transported, by truck, for approximately 10 hours. Peripheral blood mononuclear cells (PBMCs) were assayed in order to evaluate the phenotype of lymphocyte subsets by flow, mitogen-specific immune responses of PBMCs in vitro, and levels of cytokines at various time points including immediately before transport, immediately upon arrival, and after approximately 150 days of acclimation. We observed significant changes in T cells and subsets, NK and B cells (CD4+, CD8+, CD4+/CD8+, CD16+, and CD20+). Mitogen specific (e.g. PHA, PWM and LPS) proliferation responses, IFN-γ by ELISPOT assay, and cytokines (IL-2, IL-4 and VEGF) significant changes were observed. Changes seen in the serum chemistry measurements mostly complement those seen in the hematology data. The specific goal was to empirically assess the effects of relocation stress in squirrel monkeys in terms of changes in the numbers and functions of various leukocyte subsets in the blood and the amount of time required for acclimating to their new environment. Such data will help to determine when newly arrived animals become available for use in research studies.
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neonatal activity and state control differences among three squirrel monkey subspecies Saimiri sciureus sciureus s Boliviensis Boliviensis and s Boliviensis peruviensis
American Journal of Primatology, 2020Co-Authors: Michele M Mulholland, Lawrence E. Williams, Christian R. AbeeAbstract:Squirrel monkeys are a long-standing biomedical model, with multiple species and subspecies housed in research facilities. Few studies have examined the developmental differences between these subspecies, which may affect research outcomes. The primate neonatal neurobehavioral assessment was completed at 2 weeks of age with 279 dam-reared squirrel monkeys (188 Saimiri Boliviensis Boliviensis, 45 S. b. peruviensis, and 46 Saimiri. sciureus sciureus). Activity, orientation to stimuli, state control, and motor maturity scores, as well as startle responses and number of vocalizations were compared across subspecies and sex using factorial analysis of covariance (ANCOVAs) controlling for birthweight. There were no differences in orientation or motor maturity scores (p > .05) among the three subspecies or between sexes; however, there were significant subspecies differences in motor activity and state control scores. Of the three subspecies, S. s. sciureus has the lowest state control and activity scores (p < .05). They also had the most exaggerated startle response/aversion to a sudden loud noise, vocalized significantly less, and were less likely to resist restraint during the assessment (p < .05). The three subspecies of squirrel monkeys did not differ in motor development and attention to external stimuli but were significantly different in state control and activity levels. Overall S. s. sciureus were less active, agitated, irritable, and easier to console compared to S. b. Boliviensis and S. b. peruviensis. This supports field research on socioecology which documented different social structure and behavior in wild populations of S. s. sciureus compared to S. b. Boliviensis and S. b. peruviensis.
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effects of relocation on immunological and physiological measures in squirrel monkeys Saimiri Boliviensis Boliviensis
bioRxiv, 2020Co-Authors: Pramod N. Nehete, Bharti P. Nehete, Greg K Wilkerson, Steve J Schapiro, Lawrence E. WilliamsAbstract:Abstract In the present study, we have quantified the effects of transport, relocation and acclimate/adapt to their new surroundings on squirrel monkey. These responses are measured in blood samples obtained from squirrel monkeys, at different time points relative to their relocation from their old home to their new home. A variety of immunological assays are performed on the phenotype and function of peripheral blood mononuclear cells (PBMCs) in a group of squirrel monkeys that were transported by road for approximately 10 hours from one facility to another. Using a panel of human antibodies and a set of standardized human immune assays, we evaluated the phenotype of lymphocyte subsets by flow, mitogen-specific immune responses of PBMCs in vitro, and levels of cytokines at various time points including immediately before transport, immediately upon arrival, and after approximately 150 days of acclimation. We observed significant changes in T cells and subsets, NK and B cells (CD4+, CD8+, CD4+/CD8+, CD16+, and CD20+). Mitogen specific (e.g. PHA, PWM and LPS) proliferation responses, IFN-g by ELISPOT assay, and cytokines (IL-2, IL-4 and VEGF) significant changes were observed. Changes seen in the serum chemistry measurements mostly complement those seen in the hematology data. The specific goal was to empirically assess the effects of relocation stress in squirrel monkeys in terms of changes in the numbers and functions of various leukocyte subsets in the blood and the amount of time require for acclimating to their new environment. Such data will help to determine when newly arrived animals become available for use in research studies.
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class c cpg oligodeoxynucleotide immunomodulatory response in aged squirrel monkey Saimiri Boliviensis Boliviensis
Frontiers in Aging Neuroscience, 2020Co-Authors: Pramod N. Nehete, Bharti P. Nehete, Sriram Chitta, Henrieta Scholtzova, Lawrence E. Williams, Akash G Patel, Margish Ramani, Thomas WisniewskiAbstract:One means of stimulating the mammalian innate immune system is via Toll-like receptor 9 (TLR9) being exposed to unmethylated cytosine-phosphate-guanine (CpG) DNA, also known as pathogen-associated molecular patterns of microbial origin. Synthetic CpG oligodeoxynucleotides (ODNs) with defined CpG motifs possess broad immunostimulatory properties that make CpG ODNs suitable as therapeutic interventions in a variety of human disease conditions, including Alzheimer’s disease (AD). Rodent models are often used for preclinical testing of the effectiveness of CpG ODN therapeutic agents for AD and other disorders. However, the translatability of findings in such models is limited due to the significant difference of the distribution of TLR9 between primates and rodents. The squirrel monkey (SQM), a well-established New World non-human primate (NHP), is known to be phylogenetically proximate to humans and develops extensive age-dependent cerebral amyloid angiopathy (CAA), a key pathological feature of AD. Hence, this model is currently being used to test AD therapeutics. In the present study, we conducted the first examination of Class C CpG ODN’s immunomodulatory role in elderly SQMs. We documented the effectiveness of CpG ODN to trigger an immune response in an aged cohort whose immune system is senescent. The specific immune response patterns detected here, closely resembled CpG ODN-induced immunostimulatory patterns observed in prior human studies. Overall, our findings provide critical data regarding the immunomodulatory potential of CpG ODN in this NHP model allowing for future therapeutic trials of innate immunity stimulation via TLR9 agonists for diverse indications including AD therapeutics.
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class c cpg oligodeoxynucleotide immunomodulatory response in aged squirrel monkey Saimiri Boliviensis Boliviensis
Frontiers in Aging Neuroscience, 2020Co-Authors: Pramod N. Nehete, Bharti P. Nehete, Sriram Chitta, Henrieta Scholtzova, Lawrence E. Williams, Akash G Patel, Thomas Wisniewski, Margish D RamaniAbstract:One means of stimulating the mammalian innate immune system is via Toll-like receptor 9 (TLR9) being exposed to unmethylated cytosine-phosphate-guanine (CpG) DNA, also known as pathogen-associated molecular patterns (PAMPs) of microbial origin. Synthetic CpG oligodeoxynucleotides (ODNs) with defined CpG motifs possess broad immunostimulatory properties that make CpG ODNs suitable as therapeutic interventions in a variety of human disease conditions, including Alzheimer's disease (AD). Rodent models are often used to preclinically test the effectiveness of CpG ODN therapeutic agents for AD and other disorders. However, the translatability of findings in such models is limited due to the significant difference of the expression of TLR9 between primates and rodents. The squirrel monkey (SQM), a New World non-human primate (NHP), is known to be phylogenetically proximate to humans, and develops extensive age-dependent cerebral amyloid angiopathy (CAA), a key pathological feature of AD. Hence, this model is currently being used to test AD therapeutics. In the present study, we conducted the first examination of Class C CpG ODN's immunomodulatory role in elderly SQMs. We documented the effectiveness of CpG ODN to trigger an immune response in an aged cohort whose immune system is senescent. The specific immune response patterns detected here closely resembled CpG ODN-induced immunostimulatory patterns observed in prior human studies. Overall, our findings provide critical data regarding the immunomodulatory potential of CpG ODN in this NHP model, allowing for future translational studies of innate immunity stimulation via TLR9 agonists for diverse indications, including AD therapeutics.
Richard R Yeoman - One of the best experts on this subject based on the ideXlab platform.
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midcycle and luteal elevations of follicle stimulating hormone in squirrel monkeys Saimiri Boliviensis during the estrous cycle
American Journal of Primatology, 2000Co-Authors: Lawrence E. Williams, Richard R Yeoman, Susan V Gibson, Fredrick Wegner, David H Abbott, Christian R. AbeeAbstract:Follicle stimulating hormone (FSH) has fundamental importance in reproductive function, but its cyclic pattern has not previously been described in the squirrel monkey, due primarily to the lack of a suitable assay. An homologous radioimmunoassay (RIA) based on recombinant cynomolgus FSH measured changes in serum FSH relative to patterns of bioactive luteinizing hormone (LH), estradiol, and progesterone during the estrous cycle. FSH was observed to have a sharp peak during the late follicular phase coincident with the LH surge and then rose again during the luteal phase. Estradiol was low except for the midcycle rise, suggesting an inhibitory relationship. The rat granulosa cell in vitro FSH bioassay confirmed high levels of this hormone. Measurement of FSH in the squirrel monkey has found a pattern different from Old World primates in the luteal phase, which may provide insight into the reproductive mechanisms of this species.
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elevated ovarian expression and serum concentration of α inhibin in the luteal phase during follicular development in the squirrel monkey Saimiri Boliviensis compared to the human
American Journal of Primatology, 1999Co-Authors: Richard R Yeoman, Botros Rizk, L M Crews, D B Zimmer, K D Dahl, Christian R. AbeeAbstract:The goal of the present investigation was to determine in the squirrel monkey the source and pattern of inhibin, a hormone known to effect reproductive steroid levels via pituitary and ovarian mechanisms. Since this seasonally polyestrous species is known to have elevated serum levels of reproductive steroids compared to other primates, the levels of ovarian alpha subunit mRNA expression and serum total alpha inhibin, estradiol, progesterone, and luteinizing hormone were measured and compared to human levels. Expression of the alpha subunit was robust in monkey luteal tissue compared to expression in human luteal tissue. Squirrel monkey serum inhibin peaked 4 days after the luteinizing hormone surge and correlated with progesterone changes. These luteal serum levels of inhibin were greater than 12 times higher than the human levels yet bio-LH activities were less than in the human during the luteal phase. Inhibin concentrations during the non-breeding season were generally half the levels measured in the breeding season and undetectable in ovariectomized animals. However, exogenous FSH stimulation induced a marked rise in inhibin, which correlated with an estradiol rise. In conclusion, abundant alpha inhibin subunit expression in the luteal ovary of the squirrel monkey and loss of serum delectability in ovariectomized animals indicates that the principle source of inhibin in the squirrel monkey is the ovary. Elevated serum inhibin levels during the luteal phase concurrent with ovulatory-size follicular development is unique among species studied thus far. Possible simultaneous inhibin production from both follicular and luteal tissue may be responsible for the exceptionally high inhibin levels. Am. J. Primatol. 47:165–179, 1999. © 1999 Wiley-Liss, Inc.
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penile vibratory stimulation yields increased spermatozoa and accessory gland production compared with rectal electroejaculation in a neurologically intact primate Saimiri Boliviensis
Human Reproduction, 1998Co-Authors: Richard R Yeoman, Susan V Gibson, Jens Sonksen, Botros Rizk, Christian R. AbeeAbstract:Assisted reproductive techniques require an efficient semen collection procedure in cases of ejaculatory dysfunction. Anejaculation may be of psychogenic or neurogenic origin but can be overcome with stimulatory techniques. Penile vibratory stimulation (PVS) therapy for anejaculation has recently emerged as an alternative to rectal probe electroejaculation (RPE) and more invasive testicular procedures. Comparison of the stimulatory procedures in neurologically intact subjects is not ethically possible due to the discomfort involved with electroejaculation, and comparison in spinal cord injured men may be compromised due to the intricate effects of chronic denervation on semen quality. We have previously shown the efficacy of PVS in a non-human primate, the squirrel monkey. A cross-over study design comparing semen collected by PVS and RPE was employed during the breeding season in which 15 donor males were divided into two groups. One group received PVS and the other RPE, then, three days later, treatments were reversed. Twelve of 15 animals responded to PVS (80%), all with spermatozoa in the ejaculate. Mean volume (436 +/- 90 microl), motility (80.6 +/- 4.3%), and total spermatozoa (32.8 +/- 10.2 x 10(6)) were significantly higher than in the semen after RPE. RPE resulted in ejaculation in all 15 animals with a semen volume of 205 +/- 25 microl, but fewer samples contained spermatozoa (9/15) resulting in a low total count (0.5 +/- 0.3 x 10(6)). The motility was reduced in those samples with spermatozoa (n = 9; 44.1 +/- 11.4%). Additionally, accessory gland activity was measured via the seminal vesicle and prostrate markers, fructose and citric acid, respectively. The PVS specimens had significantly more fructose (2.9 +/- 0.7 mg/ejaculate) and citric acid (0.46 +/- 0.14 mg/ejaculate) compared to RPE collected specimens (1.2 +/- 0.3 mg/ejaculate and 0.24 +/- 0.04 mg/ejaculate, respectively). In conclusion, PVS produces a much greater sperm yield and increased accessory gland secretion compared to RPE in our neurologically intact squirrel monkey model.
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vibratory stimulation of ejaculation yields increased motile spermatozoa compared with electroejaculation in squirrel monkeys Saimiri Boliviensis
Contemporary Topics in Laboratory Animal Science, 1997Co-Authors: Richard R Yeoman, Lawrence E. Williams, Robert B Ricker, Jens Sonksen, Christian R. AbeeAbstract:Semen sample collection in squirrel monkeys has traditionally relied on electroejaculation (EE) via the rectum; how- ever, the yield is low when anesthesia is used. An alternative method has been advocated for men with spinal cord injury that relies on penile vibratory afferent stimulation. Vibratory stimulation (VS) physiologically coordinates emission and ejaculation without requiring anesthesia; this procedure was investigated in squirrel monkeys. During the breeding season, 10 donor males were evenly allotted to two groups; one received VS, and the other received EE. Three days later, treatments were reversed. For VS, a clinical unit was adapted to hold a 1.8-ml microcentrifuge tube as an artificial vagina. Unanesthetized, manually restrained animals were positioned in ventral recumbency. Vibratory stimulation consisted of a I-mm amplitude, 75-Hz stimulation for 1 min, rest for 1 min, then continued stimulation at 1.8-mm amplitude, 90 Hz for 1 min. For EE, animals were anesthetized by administration of Telazol(3.5 mg/kg of body weight, IM) and stimulated by EE via the rectum, using a 5- to 7.5-V, 60-Hz sine wave for 1 minute of 1 sec on/ I sec off and a probe with two longitudinal electrodes and a temperature monitor. Stimulation was repeated after 1 minute s rest. Semen samples were diluted, incubated, centrifuged, and evaluated for spermatozoal count and motility. Nine of 10 monkeys responded to VS with semen samples, all of which contained spermatozoa. Mean motility was 79.8% and total mean motile spermatozoa yield was 26.1 (range, 0.4 to 110) million. By use of EE, all monkeys produced semen samples, but only 6 samples contained spermatozoa, with mean motility of 70% and low yield of 0.534 (range, 0.038 to 2.2) million motile spermatozoa. In conclusion, penile VS was superior with regard to quantity of motile spermatozoa obtained. Additionally, no anesthesia was necessary for this relatively benign procedure.
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restoration of oocyte maturational competency during the nonbreeding season with follicle stimulating hormone stimulation in squirrel monkeys Saimiri Boliviensis Boliviensis
Biology of Reproduction, 1994Co-Authors: Richard R Yeoman, Sezer Aksel, Lawrence E. Williams, Ahmet Helvacioglu, Christian R. AbeeAbstract:The in vitro maturation potential of oocytes retrieved during the nonbreeding season with or without prior in vivo low-dose FSH stimulation was studied in adult squirrel monkeys (Saimiri Boliviensis Boliviensis). Additionally, the adequacy of various protein supplements in media used for oocyte maturation was investigated. Ovaries were removed from animals in the nonbreeding season (n = 9) with or without prior treatment with a low dose (1 mg) of FSH for four days before ovariectomy. Minimal estradiol elevation was observed in serum even with stimulation. For oocyte collection, ovaries were placed in warmed 21 mM HEPES-buffered Ham's F-10. Oocytes from unstimulated ovaries were retrieved and cultured (47 of 62 recovered) in bicarbonate-buffered Ham's F-10 medium containing 0.5% BSA as protein supplement. Negligible maturation was observed at 48 h (3 of 47; 6% ), and no fertilization was seen after insemination. Immature oocytes from animals stimulated with a low dose of FSH were cultured (69 of 94 recovered). With prior FSH stimulation, oocytes placed in 0.5% BSA medium matured (13 of 24; 54%) and fertilized (7 of 21; 33%) in marked contrast to oocytes from the nonstimulated monkeys. Additionally, 20% monkey serum and 20% human follicular fluid were studied as alternative protein supplements for the FSH-pretreated oocytes; these produced similar maturation rates (10 of 22, 45%; 10 of 23, 43%, respectively) and fertilization rates (8 of 21, 38%; 6 of 21, 29%, respectively). In some cases, 2 pronuclei were observed at 16 h and 4 cells were observed at 40 h. Of those activated, 63% showed cleavage ranging from 2 to 8 cells by 96 h. The results of this study in the squirrel monkey indicated that during the nonbreeding season, maturational competency was lost but could be restored by in vivo stimulation with a low dose of FSH. Additionally, the findings show that Ham's F-10 supplemented with either 0.5% BSA, 20% monkey serum, or 20% human follicular fluid will support maturation of squirrel monkey oocytes in vitro once competency has been achieved.
Jesse W Young - One of the best experts on this subject based on the ideXlab platform.
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tail function during arboreal quadrupedalism in squirrel monkeys Saimiri Boliviensis and tamarins saguinus oedipus
Journal of Experimental Zoology, 2015Co-Authors: Jesse W Young, Gabrielle A Russo, Connie D Fellmann, Meena A Thatikunta, Brad A ChadwellAbstract:The need to maintain stability on narrow branches is often presented as a major selective force shaping primate morphology, with adaptations to facilitate grasping receiving particular attention. The functional importance of a long and mobile tail for maintaining arboreal stability has been comparatively understudied. Tails can facilitate arboreal balance by acting as either static counterbalances or dynamic inertial appendages able to modulate whole-body angular momentum. We investigate associations between tail use and inferred grasping ability in two closely related cebid platyrrhines—cotton-top tamarins (Saguinus oedipus) and black-capped squirrel monkeys (Saimiri Boliviensis). Using high-speed videography of captive monkeys moving on 3.2 cm diameter poles, we specifically test the hypothesis that squirrel monkeys (characterized by grasping extremities with long digits) will be less dependent on the tail for balance than tamarins (characterized by claw-like nails, short digits, and a reduced hallux). Tamarins have relatively longer tails than squirrel monkeys, move their tails through greater angular amplitudes, at higher angular velocities, and with greater angular accelerations, suggesting dynamic use of tail to regulate whole-body angular momentum. By contrast, squirrel monkeys generally hold their tails in a comparatively stationary posture and at more depressed angles, suggesting a static counterbalancing mechanism. This study, the first empirical test of functional tradeoffs between grasping ability and tail use in arboreal primates, suggests a critical role for the tail in maintaining stability during arboreal quadrupedalism. Our findings have the potential to inform our functional understanding of tail loss during primate evolution. J. Exp. Zool. 323A: 556–566, 2015. © 2015 Wiley Periodicals, Inc.
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ontogeny of limb force distribution in squirrel monkeys Saimiri Boliviensis insights into the mechanical bases of primate hind limb dominance
Journal of Human Evolution, 2012Co-Authors: Jesse W YoungAbstract:Abstract The distribution of peak vertical forces between the forelimbs and the hind limbs is one of the key traits distinguishing primate quadrupedal locomotion from that of other mammals. Whereas most mammals generate greater peak vertical forelimb forces, primates generate greater peak vertical hind limb forces. At the ultimate level, hind limb dominance in limb force distribution is typically interpreted as an adaptation to facilitate fine-branch arboreality. However, the proximate biomechanical bases for primate limb force distribution remain controversial. Three models have been previously proposed. The Center of Mass (COM) Position model attributes primates’ unique mode of limb loading to differences in the position of the whole-body COM relative to the hands and feet. The Active Weight Shift model asserts that primates actively redistribute body weight to their hind limbs by pitching the trunk up via the activation of hind limb retractor muscles. Finally, the Limb Compliance model argues that primates selectively mitigate forelimb forces by maintaining a compliant forelimb and a flat shoulder trajectory. Here, a detailed dataset of ontogenetic changes in morphology and locomotor mechanics in Bolivian squirrel monkeys ( Saimiri Boliviensis ) was employed as a model system to evaluate each of these proposed models in turn. Over the first 10 months of life, squirrel monkeys transitioned from forelimb dominant infants to hind limb dominant juveniles, a change that was precipitated by decreases in peak vertical forelimb forces and increases in peak vertical hind limb forces. Results provided some support for all three of the models, although the COM Position and Active Weight Shift models were most strongly supported by the data. Overall, this study suggests that primates may use a variety of biomechanical strategies to achieve hind limb dominance in limb force distribution.
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gait selection and the ontogeny of quadrupedal walking in squirrel monkeys Saimiri Boliviensis
American Journal of Physical Anthropology, 2012Co-Authors: Jesse W YoungAbstract:Locomotor researchers have long known that adult primates employ a unique footfall sequence during walking. Most mammals use lateral sequence (LS) gaits, in which hind foot touchdowns are followed by ipsilateral forefoot touchdowns. In contrast, most quadrupedal primates use diagonal sequence (DS) gaits, in which hind foot touchdowns are followed by contralat- eral forefoot touchdowns. However, gait selection in immature primates is more variable, with infants and juveniles frequently using LS gaits either exclusively or in addition to DS gaits. I explored the developmental bases for this phenomenon by examining the ontogeny of gait selection in juvenile squirrel monkeys walking on flat and simulated arboreal substrates (i.e., a raised pole). Although DS gaits predominated throughout de- velopment, the juvenile squirrel monkeys nonetheless utilized LS gaits in one-third of the ground strides and in one-sixth of pole strides. Multiple logistic regression analyses showed that gait selection within the juvenile squirrel monkey sample was not significantly associated with either age or body mass per se, arguing against the oft-cited argument that general neuromuscular matura- tion is responsible for ontogenetic changes in preferred footfall sequence. Rather, lower level biomechanical vari- ables, specifically the position of the whole-body center of mass and the potential for interference between ipsi- lateral fore and hindlimbs, best explained variation in footfall patterns. Overall, results demonstrate the prom- ise of developmental studies of growth and locomotor de- velopment to serve as ''natural laboratories'' in which to explore how variability in morphology is, or is not, asso- ciated with variability in locomotor behavior. Am J Phys Anthropol 000:000-000, 2012. V C 2012 Wiley Periodicals, Inc.
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quadrupedal locomotion of Saimiri Boliviensis a comparison of field and laboratory based kinematic data
2011Co-Authors: Liza J Shapiro, Jesse W Young, Art SoutherAbstract:As a result of a plethora of lab-based studies focusing on primate quadrupedalism, it is well known that compared to most other mammals, primates exhibit distinctive quadrupedal kinematics when moving on artificial “terrestrial” or “arboreal” substrates. However, we have little knowledge of how quadrupedal kinematics are impacted by the complexity of natural habitats, in which pathways may be obstructed, unstable, or vary dramatically in size, orientation, shape, or texture. In this study, we compared data on the quadrupedal kinematics of Saimiri Boliviensis in both laboratory and field settings by comparing kinematic responses across laboratory substrates (pole, floor) and natural substrates (branches that varied in size and orientation). Field results indicate that Saimiri Boliviensis adjusted to larger branches by increasing limb duty factors, but used a wide variety of gait types (as measured by limb phase) across all branch sizes and orientations, rather than fine tuning limb phase to these aspects of substrate. Lab poles elicited similar average limb phases and duty factors, but reduced gait flexibility compared to branches. Lab studies would benefit from greater complexity of simulated arboreal substrates, and field studies should strive to measure numerous substrate characteristics to most effectively test hypotheses about the adaptive nature of primate locomotion.
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ontogeny of joint mechanics in squirrel monkeys Saimiri Boliviensis functional implications for mammalian limb growth and locomotor development
The Journal of Experimental Biology, 2009Co-Authors: Jesse W YoungAbstract:SUMMARY Juvenile animals must often compete against adults for common resources, keep pace during group travel and evade common predators, despite reduced body size and an immature musculoskeletal system. Previous morphometric studies of a diverse array of mammals, including jack rabbits, cats and capuchin monkeys, have identified growth-related changes in anatomy, such as negative allometry of limb muscle mechanical advantage, which should theoretically permit young mammals to overcome such ontogenetic limits on performance. However, it is important to evaluate the potential impact of such `compensatory9 growth trajectories within the context of developmental changes in locomotor behavior. I used standard kinematic and kinetic techniques to investigate the ontogenetic scaling of joint postures, substrate reaction forces, joint load arm lengths and external joint moments in an ontogenetic sample of squirrel monkeys ( Saimiri Boliviensis ). Results indicated that young squirrel monkeys were frequently able to limit forelimb and hind limb joint loading via a combination of changes in limb posture and limb force distribution, potentially compensating for limited muscularity at younger ages. These results complement previous morphometric studies and suggest that immature mammals may utilize a combination of behavioral and anatomical mechanisms to mitigate ontogenetic limits on locomotor performance. However, ontogenetic changes in joint posture, not limb length per se , explained most of the variation in load arm lengths and joint loading in growing squirrel monkeys, indicating the importance of incorporating both anatomical and performance measures when studying the ontogeny of limb joint mechanics.
Bertha K Madras - One of the best experts on this subject based on the ideXlab platform.
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effects of daily δ9 tetrahydrocannabinol thc alone or combined with cannabidiol cbd on cognition based behavior and activity in adolescent nonhuman primates
Drug and Alcohol Dependence, 2021Co-Authors: Sarah L Withey, Jack Bergman, Susan R George, Brian D Kangas, Sophia Charles, Andrew B Gumbert, Jessica E Eisold, Bertha K MadrasAbstract:Background Daily use of marijuana is rising in adolescents, along with consumption of high potency marijuana products (high % Δ-9-tetrahydrocannabinol or THC). These dual, related trends have opened gaps in understanding the long-term effects of daily consumption of a high dose of THC in adolescents and whether a therapeutic dose of cannabidiol (CBD) modulates THC effects. Methods Adolescent squirrel monkeys (Saimiri Boliviensis) were treated daily for four months with vehicle (n = 4), a high THC dose (1 mg/kg i.m.; n = 4), or THC + CBD (1 mg/kg +3 mg/kg i.m.; n = 4), to investigate whether: (1) a daily high THC dose affects performance in tasks of cognition (repeated acquisition, discrimination reversal); (2) a daily high THC dose affects spontaneous behavior and day/night activity (3) tolerance develops to the behavioral effects of THC; (4) whether CBD modulates THC effects. Results THC impaired performance of adolescent monkeys in a cognitive test initially, but not performance on a task of cognitive flexibility. THC reduced motor activity and increased sedentary behavior, with tolerance developing after weeks of daily treatment. Co-administered with THC, CBD did not modulate THC effects on cognitive performance, activity or tolerance, but prevented THC-induced emesis on the first day of daily treatment. Conclusions Daily high dosing with THC compromised performance on a task of cognition, and reduced activity in adolescent primates, with tolerance developing within weeks. Whether our observations are relevant to a broader range of cognitive tasks vital for daily function in human adolescents is uncertain.
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thc and cbd blood and brain concentrations following daily administration to adolescent primates
Drug and Alcohol Dependence, 2020Co-Authors: Sarah L Withey, Jack Bergman, Marilyn A Huestis, Susan R George, Bertha K MadrasAbstract:Abstract Background Cannabis availability with high concentrations of Δ-9-tetrahydrocannabinol (THC) and a range of THC to cannabidiol (CBD) ratios has increased in parallel with a rise in daily cannabis consumption by adolescents. Unanswered questions in adolescents include: 1) whether THC blood concentrations and THC metabolites remain stable or change with prolonged daily dosing, 2) whether CBD modulates THC pharmacokinetic properties and alters THC accumulation in brain, 3) whether blood THC levels reflect brain concentrations. Methods In adolescent squirrel monkeys (Saimiri Boliviensis), we determined whether a four-month regimen of daily THC (1 mg/kg) or CBD (3 mg/kg) + THC (1 mg/kg) administration (IM) affects THC, THC metabolites, and CBD concentrations in blood or brain. Results Blood THC concentrations, THC metabolites and CBD remained stable during chronic treatment. 24 h after the final THC or CBD + THC injection, blood THC and CBD concentrations remained relatively high (THC: 6.0–11 ng/mL; CBD: 9.7−19 ng/mL). THC concentrations in cerebellum and occipital cortex were approximately twice those in blood 24 h after the last dose and did not significantly differ in subjects given THC or CBD + THC. Conclusions In adolescent monkeys, blood levels of THC, its metabolites or CBD remain stable after daily dosing for four months. Our model suggests that any pharmacological interactions between CBD and THC are unlikely to result from CBD modulation of THC pharmacokinetics. Finally, detection of relatively high brain THC concentrations 24 h after the final dose of THC suggests that the prolonged actions of THC may contribute to persistent cognitive and psychomotor disruption after THC- or cannabis-induced euphoria wane.
