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Incorporation of (3H) lysine into the brain and spinal cord of the cebus (Cebus appella) and rhesus (Macacca mulata) monkeys.

The relative amounts of incorporation of [3H] lysine into various brain areas and segments of the spinal cord in adult Cebus and Rhesus monkeys were studied. One hour after subcutaneous injection of [3H] lysine, animals were sacrificed and the brain and spinal cord samples taken and processed for [3H] lysine incorporation into protein (Lowry et al., 1951; Wells and Bernstein, 1976). Analysis revealed marked differences in metabolism among brain areas within each species of monkey as well as across species. Cortical structures were generally higher in radioactive uptake than subcortical structures in both species. The Cebus monkey had the greatest variation among brain areas, particularyly between cortical regions, whereas the Rhesus monkey did not show cortical variation in uptake. The ratio of incorporated to nonincorporated lysine in the brain and spinal cord was higher in the Rhesus than the Cebus monkey. Both species showed a rostrocaudal gradient of radioactivity following [3H] lysine incorporation into the spinal cord. Considering weight, size, and availability differences, the metabolism of [3H] lysine appears to differ by brain areas and spinal cord segments between species.

Animals↗

Protein requirements of adult cebus monkeys (Cebus albifrons).

Twenty-nine adult cebus monkeys (18 males and 11 females) were used in long-term feeding experiments designed to study the protein requirements of this species. By feeding an otherwise adequate diet containing graded levels of lactalbumin, it was shown that diets containing 7.5% of the calories as protein were necessary for long-term weight maintenance. This estimate is compared to data obtained with young growing cebus monkeys in which 7% of the calories was sufficient for maximum growth, although it must be emphasized that due to its greater caloric intake/kg body weight, the protein intake/kg body weight of the younger animal is higher. Whereas a diet containing 9.34% protein supplied by dried bread crumbs (bread diet) was insufficient for weight maintenance of the adults, additions of 4 g lysine/kg bread crumbs and 1.5 g each methionine and threonine/kg bread crumbs produced a diet indistinguishable from the control diet (4.7% bread protein + 4.7% lactalbumin). When wheat gluten was added to the bread diet elevating the protein content to 16.2% of the calories, the amount of lysine necessary to improve the diet to weight maintenance levels increased when expressed/100 dietary kcal as compared to the bread diet alone, although the amounts in both diets were similar when expressed/g of dietary protein.

Aging↗

Assessment of the efficiency of nitrogen utilization in the infant cebus monkey (Cebus albifrons) by nitrogen balance.

Nitrogen (N) balance and growth were utilized to assess the efficiency of N utilization in the infant cebus monkey (Cebus albifrons). The efficiency of N utilization as calculated from N balance data was 35%. The efficiency of N utilization for growth was 37% as determined by weight change over a 28-day trial and by body composition data from the literature. These results indicate, therefore, that growth and N balance are comparable indicators of N utilization in these primates.

Animals↗

Postnatal growth allometry of the extremities in Cebus albifrons and Cebus apella: a longitudinal and comparative study.

Cebus albifrons and Cebus apella, partially sympatric capuchin monkeys from South America, are known to differ substantially in adult body mass and bodily proportions. C. apella possesses a robust, stocky build in contrast to the more gracile, relatively longer limbed body design of C. alblfrons. Average birth weights and adult body lengths of these two congeners, however, are remarkably similar and do not serve to distinguish them. This study examines longitudinal growth rates and patterns of ontogenetic scaling in the extremities (humerus, radius, hand, femur, tibia, foot) in order to document the nature and magnitude of skeletal changes associated with increasing age and body mass. Our data indicate that the growth rates of the six skeletal components of the limbs differ only slightly and somewhat inconsistently between the two species. Body mass, however, increases at a consistently faster rate in C. apella. Relative to body mass, therefore, the extremities of C. albifrons scale much faster than those of C. apella. This implies that at any given postnatal body mass, C. alblfrons is longer limbed that C. apella. Conversely, C. apella is heavier than C. albifrons at any given limb length or age. We suggest that such differences in body mass distribution are causally related to differences in locomotor behavior and foraging strategies. Specifically, the relatively long-limbed C. albifrons is probably more cursorial and tends to travel longer distances each day than C. apella. C. apella is a much more deliberate quadruped and is also characterized by especially vigorous and powerful foraging and feeding behaviors. We also compare our results to other (mostly cross-sectional) studies of skeletal growth allometry in nonhuman primates.

Animals↗

Physical growth of cebus monkeys, Cebus albifrons, during protein or calorie deficiency.

Infant cebus monkey (Cebus albifrons) on experimental diets providing low-protein (2.8% of calories) or low-calorie (67% of ad libitum intake) levels for 20 weeks beginning at 8 weeks of age showed marked changes in their patterns of physical growth. Significant size differences between the malnourished animals and the control group appeared within 4 weeks. Although rates of growth were significantly reduced in all measurements, all of the malnourished monkeys, including low-protein animals showing zero weight gain, continued skeletal growth (except in skull measurements) at low levels for the duration of experiment. Both the protein- and calorie-restricted animals developed a thin, emaciated appearance often associated with marasmus, not by the continuous loss of tissue byt by the redistribution of the tissue over a slowly expanding skeleton. For many skeletal proportions, the pattern and shape development in the malnourished animals differed from that of the control animals. Growth during malnutrition was most affected in those parts of the skeleton which were more advanced in relative size.

Animal Nutritional Physiological Phenomena↗

Lack of platelet monoamine oxidase activity in Cebus monkeys (Cebus albifrons).

1. Recent evidence suggests that monoamine oxidase (MAO) plays an important role modulating the extrapyramidal syndromes produced by neuroleptic drugs in both human and nonhuman primates. 2. To evaluate the possibility of using peripheral blood platelet MAO-B levels as indices of central nervous system MAO-B effects, we measured platelet MAO-B levels in Cebus monkeys that were previously tested with neuroleptics (N = 36) or drug naive (N = 6). 3. No platelet MAO-B was consistently detectable in these blood samples. 4. Thus platelet measures of MAO-B do not reliably reflect brain MAO-B function in nonhuman primates and do not offer a useful model for studying blood-brain MAO-B relationships.

Animals↗

Transfer pathways between the ovaries and the uterus in the cebus monkeys (Cebus apella).

The aim of this work was to study, in the Cebus apella monkey, the developmental changes in the microanatomy of the utero-ovarian ligament (UOL) and whether their vascular and neural elements might be involved in the transfer of signals between the ovaries and uterus. Sections including uterus, UOL, and ovary obtained from two foetuses, two prepubertal, and four cycling monkeys, two of them treated with a neuron-axonal tracer, diamidino yellow (DY) into the corpus luteum (CL) and the remaining two into the endometrium, were analyzed for the expression of neurofilament protein (NFP) and tracer distribution. Eight regularly cycling females were used to investigate the transfer to the CL of pulses of prostaglandin F(2alpha) (PGF(2alpha)) (n=4) or its vehicle (n=4) given intra-uterus. A convoluted artery, in conjunction with various vein channels, passed over the UOL allowing for a direct communication between uterus and ovaries. The artery acquired prominence during adulthood, in a manner well suited with the ovarian status. Immunohistochemical analysis revealed that NFP expression by the oocyte and by the endometrial epithelial cells was a highly conserved feature during development, whereas the appearance of NFP fibers in the ovaries, UOL, and uterus was a late event in the ontogenesis, likely regulated by the hormonal environment. Neurons, as an obvious source for these NFP fibers, were not recognized at any developmental stage, although some neuron-like cells were observed within the CL. The pattern displayed by the tracer DY, further suggested a reciprocal axonal transport among endometrial cells and follicular and luteal cells of both ovaries and between the ovaries themselves. The functionality of the utero-ovarian connection was assessed after injecting PGF(2alpha) intra-uterus. A short exposition to PGF(2alpha) pulses was required for lowering ovarian and peripheral progesterone concentrations causing luteolysis, indicating that transport mechanism operating between uterus and ovary must be very efficient. The results suggest that the vessels and axons contained in the UOL of the Capuchin monkeys might be two combined key pathways underlying the reciprocal transfer of signals controlling utero-ovarian homeostasis.

Amidines↗

Cognitive processes in Cebus monkeys (Cebus apella) when solving problem-box tasks.

Although monkeys are capable of solving problem-box tasks, they were said to perform without 'understanding the value of unlocking' and to use 'kinesthetic control' only [Kohts, 1928]. However, the cognitive processes are much more complex--at least in Cebus monkeys: the problem-solving process was conducted according to the position of the catch in relation to the edge of the door, i.e. our monkey learnt to use visual control. The main characteristics of the monkey's behavior were similar to those exhibited by children. Problem-box tasks proved to be a suitable method for the comparative analysis of cognitive processes in primates.

Animals↗

Early changes in protein synthesis following spinal cord hemisection in the Cebus monkey (Cebus apella).

The short term effects of spinal cord hemisection on protein synthesis in the Cebus monkey were studied by measuring the uptake of [3H]lysine into the trichloroacetic acid (TCA) precipitable and non-precipitable fractions of spinal cord. Animals were sacrificed 3, 6, or 13 days after hemisection. Two normal animals and a 3 day sham operate were utilized as controls. All data were pooled and subjected to analysis of variance. Significant group differences were resolved by a standad t-test over pooled operative group samples and a paired t-test for left-right differences within groups. Compared to normal animals, significant increases in the mean uptake of precursor into TCA precipitable and non-precipitable fractions of spinal cord samples were noted in all postoperative groups. The observed increase in the uptake of [3H]lysine into TCA soluble and insoluble fractions at 3 days after hemisection were attributed to stress, as were increases in the activity of the TCA insoluble fractions in the sham operate. By 6 days, the increases attributed to stress in the average protein activity seemed to subside, resulting in an overall decrease in the TCA precipitalbe protein activity with an increase in TCA soluble fraction activity. Between 6 and 13 days the activity of the TCA soluble and insoluble fractions returned to the 3 day levels with a sharp increase in the activity of both fractions in the area of the hemisection. This increase was attributed to increases in neuronal, neuroglial, and infiltrating cell metabolism possibly associated with regenerative changes.

Animals↗

Amino acid incorporation in medulla, pons, midbrain and cortex following spinal cord hemisection in the cebus monkey (Cebus apella).

The effects of spinal cord hemisection on protein labeling in the medulla, pons, midbrain, and cortex in the Cebus monkey were studied by measuring the uptake of [3H]lysine into the trichloroacetic acid (TCA) precipitable and non-precipitable fractions of brain. Animals were sacrificed 3, 6 or 13 days after hemisection. Two normal animals and a 3-day sham operate were utilized as controls. Differences included individual animals, operated vs. unoperated animals, brain areas, and variation of brain areas over all postoperative days. The overall trend in brain radioactivity over postoperative days indicates stress and non-stress related components of brain response to spinal injury. Left-right side differences (L greater than R) were noted in the uptake of [3H]lysine into specific areas of brain over postoperative time, including leg areas of motor cortex, occipital cortex, and superior colliculus. A biphasic action of leg sensory cortical areas over time was noted, where L greater than R for the first 6 postoperative days and R greater than L at day 13. The factors possibly mediating radiolabeled amino acid uptake into protein are discussed in relation to demonstrated anatomical and neurochemical regenerative processes.

Animals↗

Physical growth of cebus monkeys (Cebus albifrons) during the first year of life.

Infannt cebus monkeys, removed from their mothers shortly after birth, were reared in a primate nursery on diets of controlled nutritional quality. At regular intervals between birth and one year of age, each monkey was anesthetized, measured, and radiographed. Measurements were fitted to functions of the animal's age in days; a linear function for the first 6 to 8 weeks and a logarithmic function for the remainder of the first year. Mean constant curves have been calculated for each measure and estimates of animal variability have been obtained by interpolating sizes at given ages from regression lines fitted to the data for each animal. The maximum rate of growth was attained soon after birth. Cranial-caudal and distal-proximal maturity gradients in size attainment were observed.

Animal Nutritional Physiological Phenomena↗

Characteristics of the aortic intima in young and old cebus and squirrel monkeys.

To document naturally occurring aortic intimal changes with age in squirrel and Cebus monkeys, the aortic lipid class composition, histology, and fine structure were quantitatively compared in the two species at birth and in old age. The aortic intima plus inner media in the young squirrel monkey contained more lipid, particularly in the phospholipid and cholesterol ester fractions than in young Cebus. The lipid class composition of the old Cebus monkey aorta resembled that of the young Cebus. In the old squirrel monkey aorta, cholesteryl ester, and to a lesser extent, free cholesterol were increased over young levels, while the phospholipid concentration tended to be lower. The aortic cholesteryl ester:phospholipid ratio increased with age in both species, but the old Cebus monkey aorta maintained the ratio below unity at 0.3, whereas the old squirrel monkey aorta ratio was 2.5. The abdominal aorta of the old squirrel monkey tended to have more lipid in each class than the thoracic segment. Morphologically, the old Cebus monkey aortic intima was similar to the young Cebus in terms of the intima:media ratio, intimal cellularity, and the distribution of intimal components determined by points in electron micrographs. In both age groups the Cebus monkey aorta was characterized by diffuse intimal thickening without lipid deposits. In contrast, that old squirrel monkey aorta had a much greater intima:media ratio, especially in the abdominal aorta, and a greater intimal cellularity than the young squirrel monkey. The distribution of intimal components in electron micrographs of the old squirrel monkey aorta shifted to a predominance of extracellular lipid, smooth muscle cells, and collagen. Deposits of small dense granules, presumably the products of cellular breakdown, were observed in aortic intimas and medias of both species in old age. Thus, differences between Cebus and squirrel monkey aortic intimas were evident at birth. By old age, the Cebus monkey aortic intima remodeled without accumulating lipid, whereas the squirrel monkey developed aortic intimal lesions resembling human atherosclerosis.

Aging↗