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Biomedical subjects

K Milton

Publications and source records attributed to K Milton.

16 recordsLinked to original sources
PubMed1998

Development of Alouattamyia baeri (Diptera: Oestridae) from howler monkeys (Primates: Cebidae) on Barro Colorado Island, Panama.

The fecundity and development of larval stages of the cuterebrid bot fly A. baeri were studied in an unusual host, remotely related to the primary host. Third-instar Alouattamyia baeri (Shannon & Greene) removed from howler monkeys, Alouatta palliata, were allowed to pupate and then were cultured under controlled conditions. Eclosion occurred after 37.9 +/- 0.4 (mean +/- SE) (male) and 38.2 +/- 0.4 (female) d at 26 degrees C. Five-day-old females were mated using a tethered flight technique and oviposited on ridged filter paper. The total egg complement was 1,399 +/- 243 (n = 2) eggs per female. Eggs were fully embryonated after incubation for 5 d at 26 degrees C. Eggs hatched when warmed in the palm of the hand. Hatching of eggs from an individual batch was asynchronous. Newly hatched larvae would not penetrate intact skin on a rabbit, Oryctolagus cuniculus L. Larvae placed near the nares or on the ocular conjunctiva migrated rapidly from view. Warbles containing larvae were first observed on infested rabbits 5 d after infestation. Development of larvae proceeded until day 39 after infestation, when nearly mature 3rd instars were observed. None of the larvae survived to pupate.

Alouatta↗
PubMed1996

Antibody immunoglobulin G (IgG) response to Alouattamyia baeri (Diptera:Cuterebridae) parasitism of howler monkeys, Alouatta palliata, in Panama.

Larval bot fly burdens and the presence of immunoglobulin G (IgG) antibodies to larval antigens of Alouattamyia baeri (Shannon & Greene) were determined in howler monkeys, Alouatta palliata authority, from Barro Colorado Island, Panama, during July and August of 1991 and 1992. Monkeys produced antibodies (IgG) to both 1st- and 3rd-instar proteins of the monkey bot as measured by an enzyme immunoassay. The response to 1st-instar antigen was correlated with number of bots for the 1991 data and for pooled data from 1991 and 1992. No correlation was observed for the response to 3rd instar antigen. First-instar extracts were composed of 9 major proteins as visualized by SDS-PAGE. Bands at 17, 25, and 32 kDa were positive in Western blots. Third-instar extracts contained at least 13 major bands, with those at 120 and 130 kDa reactive in immunoblots. The immune response to A. baeri may be involved in limiting larval bot numbers.

Alouatta↗
PubMed1993

Fatty acid profiles of major food sources of howler monkeys (Alouatta palliata) in the neotropics.

Wild howler monkeys (Alouatta palliata) get most of their calories from carbohydrates (65%) and fats (18%) of native tropical plants, but little is known about their intake of individual fatty acids. The fatty acid composition of several natural food sources of howler monkeys collected in Panama was determined by gas-liquid chromatography. The predominant fatty acids were palmitic (30%), linoleic (23%), alpha-linolenic (16%) and oleic (15%). Fatty acids with less than 16, and more than 18, carbon chains were uncommon (0-7%). Although total saturated fatty acids were high in some specific food sources (22-54% of total fatty acids and 8 energy %), most of the calories from fat in the animals' diets are derived from mono- and polyunsaturated fatty acids (9.75 energy %). All food sources had significant amounts of the omega-3 fatty acid, alpha-linolenic acid (2.9 energy %). In terms of human diets, the howler monkey's fat consumption would not be considered atherogenic. Unless these animals show a particular adverse susceptibility to dietary fat, it is unlikely that their fat intake is the primary cause of the low, but significant, incidence of atherosclerosis that develops in these animals in the wild state.

Alouatta↗
PubMed1992

Frog secretions and hunting magic in the upper Amazon: identification of a peptide that interacts with an adenosine receptor.

A frog used for "hunting magic" by several groups of Panoan-speaking Indians in the borderline between Brazil and Peru is identified as Phyllomedusa bicolor. This frog's skin secretion, which the Indians introduce into the body through fresh burns, is rich in peptides. These include vasoactive peptides, opioid peptides, and a peptide that we have named adenoregulin, with the sequence GLWSKIKEVGKEAAKAAAKAAGKAALGAVSEAV as determined from mass spectrometry and Edman degradation. The natural peptide may contain a D amino acid residue, since it is not identical in chromatographic properties to the synthetic peptide. Adenoregulin enhances binding of agonists to A1 adenosine receptors; it is accompanied in the skin secretion by peptides that inhibit binding. The vasoactive peptide sauvagine, the opioid peptides, and adenoregulin and related peptides affect behavior in mice and presumably contribute to the behavioral sequelae observed in humans.

Amino Acid Sequence↗
PubMed1991

Comparative aspects of diet in Amazonian forest-dwellers.

Recent research shows that lowland forests of the Amazon Basin differ in numerous ways including features of climate and soils, faunal composition and forest structure, composition and phenology. Such differences strongly suggest that single-factor models used to explain features of human ecology in Amazonia may be too limited. A comparative study of the dietary ecology of four forest-living indigenous groups in Brazil (Arara, Parakana, Arawete, Mayoruna) revealed a number of differences. Primary crops, as well as animal types most utilized as prey, were found to differ markedly between groups. Although some differences can be accounted for by general environmental factors, no compelling single environmental factor can explain why any one group could not behave dietarily in ways more similar to another. Many of these intergroup dietary differences appear to represent a type of cultural character displacement that aids in distinguishing the members of one group from another. As all human groups, through the medium of culture, are actual or potential occupants of the same dietary niche, each group may distance itself from potential dietary rivals through cultural conventions. This behaviour may be justified, as the lack of overlap between forest-living groups in combination with generally intense intergroup hostility suggests that the biomass and distribution patterns of critical dietary resources in this environment may set limits to viable population size for particular areas.

Animals↗
PubMed1991

The development of the sense of self in adolescence.

This study attempts to clarify the sense of self that may underlie the adolescent's subjective experience of identity. The initial orientation was provided by descriptions of three different modes of experiencing identity derived from a reanalysis of Loevinger, Wessler, and Redmore's (1970) ego development categories. Our goal was to replicate by a more direct method the Loevinger-derived descriptions. Specifically, we looked at whether the various aspects of the pre-identity mode ("Social Role Identity") and of the early identity mode ("Identity Observed") would in fact form different clusters and whether these clusters would differentiate early and middle adolescent groups. Participants were 24 sixth graders and 24 high-school seniors, equally divided by sex. In individual interviews they were asked questions concerning the main characteristics of the Identity Observed Mode. Six self scales were constructed from subjects' responses. Our two major hypotheses were strongly supported: (a) The two age groups differed dramatically on each of the self scales; and (b) the six self scales highly correlated with each other. Moreover, clusters of responses could be constructed that model the a priori descriptions of identity modes and that sharply separate the two grades.

Adolescent↗
PubMed1988

Digestion and passage kinetics of chimpanzees fed high and low fiber diets and comparison with human data.

To investigate the digestive kinetics and fiber digestion of great apes, we conducted digestion trials on chimpanzees (Pan troglodytes) with diets of two fiber levels, one containing 34% neutral detergent fiber (NDF) and the other 14% NDF. Chimpanzees exhibited a response to fiber similar to that of humans. First, increases in the fiber concentration of the diet decreased mean transit time (MTT), hindgut turnover time (T) and the digestibility of fiber. Second, differences in MTT and T between the treatments and animals explained most of the variability in the digestibility of fiber components. Third, consistent with human data, the fiber marker passed more slowly than the liquid marker only when the high fiber diet was consumed. Fourth, individual variability, as in humans, was a significant factor affecting digestion and passage. Fifth, the MTT of chimpanzees was longer than that of humans. This result may be due to the apes' larger hindgut. In comparison with other hominoids, humans have smaller volumes in the gastrointestinal tract and hindgut. The gut proportions of modern humans, in combination with evidence from the fossil record, indicate that during its evolution the human lineage was able to overcome nutritional constraints imposed on body size increases in the great apes. We suggest that this advance was achieved through technological and social innovations that permitted early humans to achieve larger body size without lowering dietary quality.

Animals↗
PubMed1987

Ascorbic acid content of neotropical plant parts available to wild monkeys and bats.

The ascorbic acid content of foliage available to wild primates and bats in Panama (in transition between wet and dry seasons) was lower than that of temperate zone foliage but higher than that of most fruits and vegetables. Intakes of ascorbic acid (mg/kg b.wt/day) by wild primates and frugivorous bats in Panama are much greater than that of most human populations.

Animal Nutritional Physiological Phenomena↗
PubMed1983

Rates of fermentative digestion in the howler monkey, Alouatta palliata (primates: ceboidea).

1. Caecal material of wild howler monkeys was analyzed by gas chromatography for evidence of fermentation activity and rates of production and absorption of volatile fatty acids. 2. Results showed a high rate of production of acetic acid and lesser production of propionic, butyric and isobutyric acids. The VFA content of the blood was increase in passage through the caecal vascular system. 3. We estimate that howler monkeys may obtain as much as 31% of their required daily energy from fermentation end products. 4. Energy rich fatty acids may be of particular importance to howlers when they are living on diets high in leaves, which have high cell wall contents and low contents of nonstructural carbohydrates.

Alouatta↗
PubMed1977

The lorisiform wrist joint and the evolution of "brachiating" adaptations in the hominoidea.

In lorisines (Loris, Nycticebus, Perodicticus, Arctocebus), the tip of the ulna is reduced to the dimensions of a styloid process, a new and more proximal ulnar head is developed, and the pisiform is displaced distally away from its primitive contact with the ulna. In some Nycticebus, intra-articular tissues separate the ulna from the triquetrum. These traits are not seen in other quadrupedal primates, but they are characteristic of extant hominoids. Among hominoids, these features have been interpreted as adaptations to arm-swinging locomotion. Since hominoid-like features of the wrist joint are found in lorisines, but not in New World monkeys that practice arm-swinging locomotion, these features may have been evolved in both lorisines and large hominoids to enhance wrist mobility for cautious arboreal locomotion involving little or no leaping. Most of the other morphological traits characteristic of modern hominoids can be explained as adaptations to cautious quadrupedalism as well as to brachiation, and may have developed for different reasons in different lineages descended from an unspecialized cautious quadruped resembling Alouatta.

Animals↗
PubMed1976

Body weight, diet and home range area in primates.

Primates show a strong positive relationship between body weight and home range area. Dietary habits also influence home range area. Folivorous primates occupy smaller home range areas for their body weight than do frugivores and omnivores. Primates generally require smaller home range area per individual than solitary terrestrial mammals, but primates living in social groups have much larger total home range than individual solitary mammals. This trend may necessitate higher expenditures of energy in food-gathering or modifications in movement patterns.

Animals↗
PubMed1975

Urine-rubbing behavior in the mantled howler monkey Alouatta palliata.

Mantled howler monkeys (Alouatta palliata) of both sexes and all age classes were observed rubbing urine on the soles of the feet and/or palms of the hands as well as the ventral surface of the tail and, occasionally, the throat. Instances of urine-rubbing were often associated with periods of troop movement or times of social stress. Intra-troop cohesion may be the primary function of such behavior. Other possible function of urine-rubbing are discussed.

Alouatta↗
PubMedDate not supplied

Isolation, structure, and synthesis of novel 4-quinolinone alkaloids from Esenbeckia leiocarpa.

Two new biocidal quinolinone alkaloids, 3-methoxy-1-methyl-2-propyl-4-quinolone [1] and 2(1'-ethylpropyl)-1-methyl-4-quinolone [2], were efficiently isolated using reversed-phase recycling hplc from the leaves of Esenbeckia leiocarpa. The structures were determined through spectroscopic data and confirmed by total synthesis. These alkaloids have antifeedant activities against the pink bollworm, Pectinophora gossypiella.

Alkaloids↗
PubMedDate not supplied

Morphometric features as tribal predictors in north-western Amazonia.

Multivariate analyses of variance were carried out on stature and weight of 50 adults (25 males, 25 females) from each of two linguistically distinct groups, Maku and Tukanoan, living sympatrically in north-western Amazonia. Results showed significant intertribal differences, with Maku (sylvan hunter-gatherers) being both shorter and lighter than their Tukanoan (riparian fisher-gardeners) conspecifics. Classification with a linear discrimination function achieved 80% accuracy. Stature or weight were equally good predictors of group for men, but for women weight rather than stature was a more powerful predictor. These data offer support for the view that some factor(s) associated with life within the equatorial forest environment appear to select for generally small body physique in humans.

Adult↗