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J Altmann

Publications and source records attributed to J Altmann.

At least 19 recordsLinked to original sources
PubMed2003

Concentrations of four fecal steroids in wild baboons: short-term storage conditions and consequences for data interpretation.

One source of both bias and "noise" in fecal steroid analysis is temporal change in steroid concentrations resulting from duration or conditions of fecal sample storage. However, no consensus currently exists regarding correct procedures or precautions necessary for fecal sample storage, and conditions vary widely within field endocrinology literature. This study considered the effects of short-term, weeks-long, storage conditions on quantifiable fecal testosterone (fT), glucocorticoids (fGC), estrogens (fE), and progestagen (fP) metabolite concentrations in wild baboons (Papio cynocephalus). Quadruplicate subsamples of fecal samples (n=29) collected at Amboseli National Park and its environs were subjected to four different storage conditions prior to lyophilization, in order to determine the effects of storage on subsequent steroid concentrations, as assessed by 125I radioimmunoassays. As expected, the best alternative to the "initial condition" of lyophilization at three days after collection was to freeze fecal samples at -20 degrees C for two weeks prior to lyophilization. This storage method resulted in no significant change from initial steroid concentrations for fE, fT, or fP, although fGC showed a slight but significant decline. Storage for two weeks in a charcoal refrigerator caused a mean increase in all four steroid concentrations. However, the results from this storage condition were robust in terms of practical questions asked of the data: fE and fP values still reflected pregnant versus non-pregnant states in baboon females; a fGC profile constructed by age class resembled that created from the samples from the initial condition, although slightly inflated across age classes; and there were only moderate changes in relative fT concentrations across adult males. Knowledge of the effects of storage upon each steroid analyzed within one's study is a necessary component in determining the optimal compromise for storage protocol in a particular research project.

Androgens↗
PubMed2002

A matter of time: evaluating the storage of fecal samples for steroid analysis.

The extraction and immunoassay of fecal steroids is an increasingly common technique, used in both captive and field studies to provide an approximation of an animal's circulating concentration of hormones through non-invasive methods. Storage of fecal samples is of critical concern because fecal bacteria metabolize fecal steroids within hours after deposit. Ethanol is often used as a preservative for fecal samples stored for several hours at room temperature. We examined the stability of fecal estrogen (fE) and glucocorticoid (fGC) metabolites from baboon (Papio cynocephalus) samples in a 95% ethanol solution at ambient temperature and at -20 degrees C over the course of six months, to determine the effect of storage on steroid concentrations. As measured by radioimmunoassay, fE metabolite concentrations increased by 122% at 90 days and fGC metabolite concentrations increased by 92% at 120 days. After peaking, both hormones declined to near initial concentrations by 180 days in ambient temperature samples. In samples stored at sub-zero temperatures, fGC metabolite concentrations showed a similar but dampened pattern, while fE metabolite concentrations exhibited small and variable changes with no consistent trend. We discuss explanations for the dynamic pattern of changing fecal metabolite concentrations and offer practical and analytical guidance to field workers for situations in which ideal conditions for stabilizing hormones are not available.

Animals↗
PubMed2001

Neuroanatomy of magnetoreception: the superior colliculus involved in magnetic orientation in a mammal.

The neural substrate subserving magnetic orientation is largely unknown in vertebrates and unstudied in mammals. We combined a behavioral test for magnetic compass orientation in mole rats and immunocytochemical visualization of the transcription factor c-Fos as a marker of neuronal activity. We found that the superior colliculus of the Zambian mole rat (Cryptomys anselli) contains neurons that are responsive to magnetic stimuli. These neurons are directionally selective and organized within a discrete sublayer. Our results constitute evidence for the involvement of a specific mammalian brain structure in magnetoreception.

Animals↗
PubMed2001

Status change during adulthood: life-history by-product or kin selection based on reproductive value?

When dominance status predicts fitness, most adaptive models of dominance relationships among cercopithecine primate females predict lifetime maintenance of status. These models and alternative ones positing rank decline as a non-adaptive by-product have remained largely untested, however, because lifetime status of older adults has been virtually unknown for natural populations. In a 25-year study of adult female savannah baboons (Papio cynocephalus), in each of three social groups, rank losses were common among the 66 females that lived past median adult age. These losses were not accounted for by loss in relative rank from group growth or by loss in absolute rank from reversals in rank between members of different maternal families or between sisters. Rather, females that had mature daughters experienced loss of dominance status to these offspring, a characteristic of all but the top-ranking matriline of each group. Among proposed hypotheses for rank reversals between adults, that of kin selection based on relative reproductive value is most clearly supported by these data. In contrast, observed patterns of rank loss are not consistent with alternative models that postulate that changes during adult lifespan are a product of accumulated risk, physical decline during ageing, or coalitionary support among females within or between matrilines.

Aging↗
PubMed2001

Immigration and hybridization patterns of yellow and anubis baboons in and around Amboseli, Kenya.

In 1986, Samuels and Altmann reported evidence for a hybrid zone between Papio anubis and Papio cynocephalus in Amboseli, Kenya, in a baboon population that has been the subject of long-term study since 1971 [Samuels & Altmann, International Journal of Primatology 7:131-138, 1986]. In the current report we document ongoing patterns of hybridization in Amboseli between anubis and yellow baboons. In July 2000, we exhaustively scored living members of study groups for their degree of hybridity, using seven phenotypic characteristics (five in juveniles). We also scored all former members of study groups on the basis of photographic records, field notes, and observer recollections. A total of five anubis males and 11 males with hybrid phenotypes have immigrated into study groups over the course of the long-term study, and immigrations by hybrid males have increased in frequency over time. Further, the increasing frequency of hybrid phenotypes among animals born into study groups indicates that anubis and hybrid males have successfully reproduced in study groups. However, hybrid phenotypes and anubis immigrations were limited to groups in the southwestern portion of the Amboseli basin, with no hybrids occurring in the six eastern groups. Finally, we present evidence that anubis and hybrid males in Amboseli exhibit patterns of natal dispersal that are different from those of yellow males in Amboseli: males with anubis or hybrid phenotypes were significantly more likely to immigrate as juveniles or young subadults than were yellow males.

Animals↗
PubMed2000

Cross-species amplification, non-invasive genotyping, and non-Mendelian inheritance of human STRPs in Savannah baboons.

Twenty-nine human microsatellite primer pairs were screened for their utility in the cross-species amplification of baboon DNA derived from both blood and feces as part of a larger study to identify paternal half sisters in a population of wild baboons (Papio cynocephalus). Forty-one percent (12/29) of the human primers successfully amplified baboon DNA. Of these 12 primers, six amplified fragments that were both polymorphic and heterozygous (mean number of alleles = 6, mean heterozygosity = 87%) and yielded repeatable results. However, only five of these six simple tandem repeat polymorphisms (STRPs) showed patterns of Mendelian inheritance (i.e., mothers and offspring shared at least one allele at each locus), and were therefore useful for determining relatedness between individuals. Analysis of the sixth primer revealed non-Mendelian inheritance, i.e., three of the six known mother-daughter pairs had no shared alleles. This failure was probably due to non-specific fragment amplification, and may have resulted from a different STRP locus being amplified in mother and daughter. This finding highlights the importance of sampling DNA from known parent-offspring pairs when screening microsatellite primers for genetic studies. Multiple, independent replications of genotypes and Mendelian checks are both particularly important when using cross-species amplification or when using a low-quality source of DNA.

Alleles↗
PubMed1998

Coronary artery injection technique: a quantitative in vivo investigation using modern catheters.

To date, there have been no quantitative in vivo assessments of contrast volumes and injection rates using modern high flow catheters during coronary angiography. Contrast volumes (n = 554), injection durations (n = 563), and injection rates (n = 498) were collected during 88 cardiac catheterizations. With increasing cathetersize (6, 7, and 8 French), injection volume increased (P < 0.0001), duration decreased (P < 0.0001), and rate increased (P < 0.0001). Compared with injections into the right coronary artery, left coronary artery injections were larger (7.1 +/- 0.1 cc vs. 4.8 +/- 0.1 cc, p < 0.0001), longer (3.6 +/- 0.05 sec vs 3.0 +/- 0.07 sec, P < 0.0001) and faster (2.1 +/- 0.04 cc/sec vs. 1.7 +/- 0.06 cc/sec, P < 0.0001). Patients with a significant stenosis in the left main or proximal right coronary artery received less contrast (P < 0.0001) more slowly (P < 0.0001) over a similar duration of injection (P = NS). When collaterals arose from the injected artery, angiographers injected more contrast (P < 0.001) over a longer period (P < 0.0001) more slowly (P < 0.0001). Catheter size and the injected vessel's location and anatomy significantly affect coronary catheterization injection technique.

Angioplasty, Balloon, Coronary↗
PubMed1997

Hypercortisolism associated with social subordinance or social isolation among wild baboons.

BACKGROUND: The phenomena of basal hypercortisolism and of dexamethasone resistance have long intrigued biological psychiatrists, and much is still unknown as to the causes and consequences of such adrenocortical hyperactivity in various neuropsychiatric disorders. We have analyzed basal cortisol concentrations and adrenocortical responsiveness to dexamethasone in a population of wild baboons living in a national park in Kenya. We tested whether social subordinance in a primate is associated with dexamethasone resistance. Furthermore, we examined whether individual differences in adrenocortical measurements were predicted by the extent of social affiliation in these animals. METHODS: Seventy yellow baboons (Papio cynocephalus) were anesthetized and injected with 5 mg of dexamethasone; the cortisol response was monitored for 6 hours. The animals were of both sexes in a range of ages and had known ranks in the dominance hierarchies within their troops. Extensive behavioral data were available for a subset of 12 adult males who were anesthetized under circumstances that also allowed for the determination of basal cortisol concentrations. RESULTS: The socially subordinate baboons were less responsive to dexamethasone than were the dominant ones; as one manifestation of this, postdexamethasone cortisol values were more than 3 times higher in the dozen lowest-ranking animals compared with the dozen highest. In addition, socially isolated males had elevated basal cortisol concentrations and showed a trend toward relative dexamethasone resistance. CONCLUSIONS: Our findings indicate that social status and degree of social affilitation can influence adrenocortical profiles; specifically, social subordinance or social isolation were associated in our study with hypercortisolism or feedback resistance.

Animals↗
PubMed1997

Behavioural risk factors in the reproduction of inbred and outbred oldfield mice

The present study investigated two rarely measured aspects of inbreeding depression: the relationship between inbreeding and behaviour, and the possibility that inbred individuals that survive infancy may still suffer from inbreeding depression by failing to breed or failing to show appropriate mating or parental behaviours. Specifically, the relationship between (1) behaviour at pairing and reproductive success, (2) inbreeding and reproductive success and (3) inbreeding and pairing behaviour, was examined in two subspecies of the oldfield mouse, Peromyscus polionotusEffects of parental and offspring inbreeding were separated through experimental design and analysis. Activity level during the first 25 days after pairing predicted future reproductive success: pairs that remained less active during the nocturnal (active) period were significantly less likely to breed than pairs that remained more active. Inbred females took significantly longer to produce their first litters and were less likely to produce litters than were outbred females, independently of whether females were related to their mates (i.e. whether their offspring would be inbred). Inactive pairs averaged fewer surviving pups than did active pairs. Inbreeding coefficient of female was a significant predictor of activity level in one of the two subspecies, suggesting that inbreeding may affect behaviour. Inbred adult females showed inbreeding depression in the form of lower conception rates and fewer surviving offspring, although the specific traits affected differed for the two subspecies. The implications for captive breeding programs, and likely causes of the subspecific differences, are discussed.

Journal Article↗
PubMed1996

Behavior predicts genes structure in a wild primate group.

The predictability of genetic structure from social structure and differential mating success was tested in wild baboons. Baboon populations are subdivided into cohesive social groups that include multiple adults of both sexes. As in many mammals, males are the dispersing sex. Social structure and behavior successfully predicted molecular genetic measures of relatedness and variance in reproductive success. In the first quantitative test of the priority-of-access model among wild primates, the reproductive priority of dominant males was confirmed by molecular genetic analysis. However, the resultant high short-term variance in reproductive success did not translate into equally high long-term variance because male dominance status was unstable. An important consequence of high but unstable short-term variance is that age cohorts will tend to be paternal sibships and social groups will be genetically substructured by age.

Animals↗
PubMed1993

Periodontal health in free-ranging baboons of Ethiopia and Kenya.

Frontal and lateral intraoral photographs of 19 baboons from the Awash National Park, Ethiopia and 37 baboons from Amboseli National Park, Kenya, were used to assess periodontal health. The Awash baboons, and two groups (Alto's and Hook's) at Amboseli, fed entirely from natural sources, but baboons from the third Amboseli group (Lodge) fed largely on food refuse from one of the park's lodges. Juveniles and adults were evaluated separately. Intraoral photographs were seriated based on visual appraisals of periodontal health. In both age groups, the best periodontal health was seen in Awash animals; Alto's and Hook's animals were intermediate, and the poorest health was seen in the Lodge sample. The periodontal health decreased with age in adult baboons, as reported in humans. Geochemistry, genetics, age, and diet (particularly variations in bacterial flora) were considered as factors contributing to the intergroup differences. Although it is not possible at present to exclude any of these as a contributing cause, we consider that diet in the broad sense (including food, water, and contamination by oral bacteria of human origin) probably plays a major role.

Age Factors↗
PubMed1993

Sex-biased lactational duration in a human population and its reproductive costs.

The authors tested the proposition that among humans (1) differences in lactational duration result in differences in costs of reproduction even under rich nutritional conditions; and (2) elimination of factors postulated to favor male-biased parental care will be reflected in elimination or reversal of sex-biased care. To do so, the authors examined the relationship between lactactational duration and fertility among Hutterites, a communal-living human population in which the levels of nutritional resources and fertility are high, breast feeding is the norm, contraceptive use is limited, and the collective social and economic system results in low resource variance among individuals. The authors demonstrate that even under good nutritional conditions, duration of nursing was a significant predictor of the length of time to next pregnancy and that nursing continued to suppress fertility after the resumption of menses. Moreover, the authors find that daughters were nursed longer than sons, leading to a longer interval to next pregnancy. The authors examine this uncommon, but not unique, finding of female-biased human parental care in the light of Hutterite social structure, and they explore the consistency of this finding with the most applicable models of parental investment.

Amenorrhea↗