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Lynne A Isbell - One of the best experts on this subject based on the ideXlab platform.

  • decline in the geographical range of the southern patas monkey Erythrocebus patas baumstarki in tanzania
    Oryx, 2009
    Co-Authors: Yvonne A De Jong, Thomas Butynski, Lynne A Isbell, Claire Lewis
    Abstract:

    The southern patas monkey Erythrocebus patas baumstarki is a subspecies thought to be endemic to central north Tanzania but its distribution and abundance is not well documented. We therefore review what is known about the historical and current distribution of the south- ern patas. It appears that, at present, the southern patas occurs in three populations, in the Serengeti, Mt Kiliman- jaro and Arusha. Since 1995 the gaps among these three populations have become larger, thereby increasing their isolation. The available data suggest that, at present, south- ern patas occur over c. 20,700 km 2 (c. 2.3% of Tanzania's land surface area). In 1995 this was c. 30,800 km 2 (c. 3.5% of the land surface area). As such, the geographical range of the southern patas has declined by c. 33% since 1995. There are unlikely to be . 900 southern patas today, and there could be , 150. Our recommendations are to (1) maintain an internet accessed database (PatasBase) into which sight- ings of the southern patas can be entered, (2) interview members of local communities to assess past and current distribution and abundance of the southern patas, (3) con- duct field studies to obtain more detailed information on the distribution, abundance, and conservation status of patas in Tanzania, (4) undertake ecological and behavioural re- search on selected groups of southern patas, and (5) prepare and implement a conservation action plan for the southern

  • distribution and abundance of patas monkeys Erythrocebus patas in laikipia kenya 1979 2004
    American Journal of Primatology, 2007
    Co-Authors: Lynne A Isbell, Janice Chism
    Abstract:

    Patas monkeys may be especially vulnerable to local extinction because they live in relatively small, female-philopatric groups at low densities and are strongly polygynous. We assessed a patas monkey population in Kenya's 9,700 km2 Laikipia District over 25 years, using data collected in 1979–1981 and 1992–2004. The data were based on intensive observations of three study groups, “on the ground” counts, and surveys of Laikipia residents. In 1979–1981, a minimum of 415 patas monkeys lived in 14–15 groups. By 2000, the best estimate suggested 310–445 patas monkeys living in 13–17 groups over a greater surveyed area, suggesting that patas monkeys in Laikipia may have undergone a slight decline in numbers over time. Their distribution, however, was similar over time. The relative stability of this population has likely been the result of beneficial co-existence with large-scale cattle ranching. Outside Laikipia, substantial habitat alteration from rising human populations has coincided with the near disappearance of patas monkeys where they were previously more numerous. The small population in Laikipia, probably the largest remaining in Kenya, may therefore be critical to the continued existence of patas monkeys in that country and may be dependent on maintenance of large-scale ranches. Such land use provides patas monkeys with water and broad expanses of Acacia drepanolobium woodlands, the habitat to which patas are restricted in Laikipia. Am. J. Primatol. 69:1223–1235, 2007. © 2007 Wiley-Liss, Inc.

  • research article distribution and abundance of patas monkeys Erythrocebus patas in laikipia kenya 1979 2004
    2007
    Co-Authors: Lynne A Isbell, Janice Chism
    Abstract:

    Kenya’s 9,700km 2 Laikipia District over 25 years, using data collected in 1979‐1981 and 1992‐2004. The data were based on intensive observations of three study groups, ‘‘on the ground’’ counts, and surveys of Laikipia residents. In 1979‐1981, a minimum of 415 patas monkeys lived in 14‐15 groups. By 2000, the best estimate suggested 310‐445 patas monkeys living in 13‐17 groups over a greater surveyed area, suggesting that patas monkeys in Laikipia may have undergone a slight decline in numbers over time. Their distribution, however, was similar over time. The relative stability of this population has likely been the result of beneficial co-existence with large-scale cattle ranching. Outside Laikipia, substantial habitat alteration from rising human populations has coincided with the near disappearance of patas monkeys where they were previously more numerous. The small population in Laikipia, probably the largest remaining in Kenya, may therefore be critical to the continued existence of patas monkeys in that country and may be dependent on maintenance of large-scale ranches. Such land use provides patas monkeys with water and broad expanses of Acacia drepanolobium woodlands, the habitat to which patas are restricted in Laikipia. Am. J. Primatol. 69:1223‐1235, 2007. ! c 2007 Wiley-Liss, Inc.

  • male demography female mating behavior and infanticide in wild patas monkeys Erythrocebus patas
    International Journal of Primatology, 2002
    Co-Authors: Karin L Enstam, Lynne A Isbell, Thomas W De Maar
    Abstract:

    Infanticide by males has been hypothesized to be a naturally selected behavioral strategy that increases the infanticidal male's reproductive success. The sexual selection hypothesis has been challenged via alternative, nonadaptive hypotheses that dispute its empirical and theoretical bases. Two of the most widely recognized alternatives are the social pathology hypothesis, in which infanticide results from overcrowding or recent human disturbance, and the generalized aggression hypothesis, in which infanticide is an epiphenomenon of increased male aggression. We report the first case of infanticide in wild, seasonally breeding patas monkeys (Erythrocebus patas) living at a low population density in a stable habitat, conditions which do not support the social pathology hypothesis. Its exceptional occurrence is consistent with the sexual selection hypothesis: over a 7-year period the infanticidal male was the only one of 13 resident males that was not present during the actual conception season but was present during the following birth season. Also consistent with this hypothesis, mothers were differentially targeted for male aggression, which increased sevenfold during the days surrounding the infanticide and then decreased to baseline levels after the infanticide. Aggression targeted at mothers does not support the generalized aggression hypothesis. As predicted by the sexual selection hypothesis, females began soliciting mating immediately after the infanticide, despite its occurrence in the nonconceptive season.

  • Differences Between Vervets (Cercopithecus aethiops) and Patas Monkeys (Erythrocebus patas) in Agonistic Interactions Between Adult Females
    International Journal of Primatology, 1998
    Co-Authors: Lynne A Isbell, Jill D. Pruetz
    Abstract:

    We examined agonistic interactions between adult females in wild, unprovisioned patas monkeys (Erythrocebus patas) and vervets (Cercopithecus aethiops). The dominance hierarchy of patas is far less clear than that of vervets. Patas had fewer interactions per dyad, fewer dyads with interactions, and a high percentage (18%) of reversals in which lower-ranking females won in agonistic interactions with higher-ranking females. Although the rank ordering of the kinds of interactions patas and vervets displayed is similar, with avoidance being the most frequently observed agonistic response to approaches by other females, patas were chased and supplanted more often than vervets were. The resources over which females were supplanted also differ between species. Supplants over food comprise smaller proportion of total supplants patas than for vervets. Patas appear to feed on less usurpable foods than vervets. We conclude that (1) Erythrocebus and Cercopithecus spp., except C. aethiops , should not be categorized with other Cercopithecinae, and C. aethiops should not be categorized with other Cercopithecus spp. and Erythrocebus , in discussions and analyses of relationships between females within groups and (2) ecological conditions, i.e., usurpability of foods, can override phylogenetic history as the selective pressure determining the nature of female competitive relationships within groups.

Ofelia A Olivero - One of the best experts on this subject based on the ideXlab platform.

  • mitochondrial toxicity in fetal Erythrocebus patas monkeys exposed transplacentally to zidovudine plus lamivudine
    AIDS Research and Human Retroviruses, 2004
    Co-Authors: Mariana Gerschenson, S W Harbaugh, J W Harbaugh, Andrea Ceresa, Jaclyn A Shaw, Vi Nguyen, Ember L. Ewings, Kunio Nagashima, Marisa St Claire, Ofelia A Olivero
    Abstract:

    This study was designed to investigate fetal mitochondrial toxicity in Erythrocebus patas monkeys exposed in utero to zidovudine (AZT) and lamivudine (3TC), and taken at term. Pregnant patas monkeys were given a daily dose of 40 mg AZT (86% of the human daily dose, based on body weight), for the last 10 weeks (50%) of gestation, and a daily dose of 24 mg 3TC (84% of the human daily dose, based on body weight) for the last 4 weeks of gestation. At term, AZT was found to be incorporated into fetal mitochondrial DNA from skeletal muscle, liver, kidney, and placenta. By transmission electron microscopy (EM) drug-exposed fetal cardiac and skeletal muscle cells showed mitochondrial membrane compromise, mitochondrial proliferation, and damaged sarcomeres, while mitochondria in brain cerebrum and cerebellum were morphologically normal. Substantial depletion of oxidative phosphorylation (OXPHOS) Complex I specific activities was observed in heart (87% reduction in mean, p = 0.02) and skeletal muscle (98% reduction...

  • mitochondrial toxicity in fetal Erythrocebus patas monkeys exposed transplacentally to zidovudine plus lamivudine
    AIDS Research and Human Retroviruses, 2004
    Co-Authors: Mariana Gerschenson, Andrea Ceresa, Jaclyn A Shaw, Vi Nguyen, Ember L. Ewings, Kunio Nagashima, Marisa St Claire, Steven W Harbaugh, Jeffrey W Harbaugh, Ofelia A Olivero
    Abstract:

    This study was designed to investigate fetal mitochondrial toxicity in Erythrocebus patas monkeys exposed in utero to zidovudine (AZT) and lamivudine (3TC), and taken at term. Pregnant patas monkeys were given a daily dose of 40 mg AZT (86% of the human daily dose, based on body weight), for the last 10 weeks (50%) of gestation, and a daily dose of 24 mg 3TC (84% of the human daily dose, based on body weight) for the last 4 weeks of gestation. At term, AZT was found to be incorporated into fetal mitochondrial DNA from skeletal muscle, liver, kidney, and placenta. By transmission electron microscopy (EM) drug-exposed fetal cardiac and skeletal muscle cells showed mitochondrial membrane compromise, mitochondrial proliferation, and damaged sarcomeres, while mitochondria in brain cerebrum and cerebellum were morphologically normal. Substantial depletion of oxidative phosphorylation (OXPHOS) Complex I specific activities was observed in heart (87% reduction in mean, p = 0.02) and skeletal muscle (98% reduction in mean, p = 0.002) from drug-exposed fetuses, compared to unexposed fetuses. In addition Complex IV activity was highly depleted (85% reduction in mean, p = 0.004) in skeletal muscle from the drug-exposed fetuses (p = 0.004). Brain cerebrum and cerebellum showed no statistically significant OXPHOS changes with drug exposure. Mitochondrial DNA quantity was substantially depleted (>50%) in heart, skeletal muscle, cerebellum, and cerebrum from drug-exposed fetuses compared to unexposed controls. Overall, the data indicate that significant mitochondrial damage was observed at birth in monkey fetuses exposed in utero to AZT plus 3TC in a human-equivalent dosing protocol.

  • transplacental genotoxicity of combined antiretroviral nucleoside analogue therapy in Erythrocebus patas monkeys
    Journal of Acquired Immune Deficiency Syndromes, 2002
    Co-Authors: Ofelia A Olivero, Juan J Fernandez, Brendan B Antiochos, Jessica L Wagner, Marisa E St Claire, Miriam C. Poirier
    Abstract:

    Summary: Antiretroviral nucleoside analogue drugs are a major constituent of highly active antiretroviral therapy (HAART). the most advanced form of treatment for HIV-1 infection. Currently, HAART combinations that include zidovudine (ZDV) and lamivudine (3TC) are highly effective in preventing HIV-1 vertical transmission; most children are born with no evident adverse clinical effects. However, ZDV is a moderately strong transplacental carcinogen in mice, and potential long-term consequences of fetal exposure to most HAART combinations remain unknown. To model human transplacental ZDV and 3TC exposures, experiments were performed in Erythrocebus patas monkeys given human-equivalent drug exposure protocols. Pregnant monkeys were dosed with either no drug (n = 2), 40.0 mg ZDV/d (about 6 mg/kg body weight/d) for the last 50% (10 weeks) of gestation (n = 3), or with the same regimen of ZDV plus 24.0 mg 3TC/d (about 3.6 mg/kg body weight/d) for the last 20% (4 weeks) of gestation (n = 3). Multiple fetal organs were examined at term for DNA incorporation of ZDV and 3TC using two separate radioimmunoassays (RIAs). Values for ZDV-DNA incorporation were similar in fetuses exposed to ZDV alone and those exposed to ZDV plus 3TC. Values for 3TC-DNA in fetal organs were greater than or equal to values for ZDV-DNA, indicating that the total DNA damage sustained by fetuses exposed to both drugs was at least double that observed in fetuses exposed to ZDV alone. Telomere shortening, determined by Southern blot with a telomeric probe, was observed in most organs of the three animals exposed in utero to ZDV plus 3TC. No telomere shortening was evident in the unexposed fetuses, and occasional telomere shortening was found in fetuses exposed to ZDV alone. Overall, these studies demonstrate that monkey fetuses exposed in utero to the combination ZDV plus 3TC sustain a higher level of drug-DNA incorporation and show evidence of more telomere damage than monkey fetuses exposed to ZDV alone.

Mariana Gerschenson - One of the best experts on this subject based on the ideXlab platform.

  • mitochondrial toxicity in fetal Erythrocebus patas monkeys exposed transplacentally to zidovudine plus lamivudine
    AIDS Research and Human Retroviruses, 2004
    Co-Authors: Mariana Gerschenson, S W Harbaugh, J W Harbaugh, Andrea Ceresa, Jaclyn A Shaw, Vi Nguyen, Ember L. Ewings, Kunio Nagashima, Marisa St Claire, Ofelia A Olivero
    Abstract:

    This study was designed to investigate fetal mitochondrial toxicity in Erythrocebus patas monkeys exposed in utero to zidovudine (AZT) and lamivudine (3TC), and taken at term. Pregnant patas monkeys were given a daily dose of 40 mg AZT (86% of the human daily dose, based on body weight), for the last 10 weeks (50%) of gestation, and a daily dose of 24 mg 3TC (84% of the human daily dose, based on body weight) for the last 4 weeks of gestation. At term, AZT was found to be incorporated into fetal mitochondrial DNA from skeletal muscle, liver, kidney, and placenta. By transmission electron microscopy (EM) drug-exposed fetal cardiac and skeletal muscle cells showed mitochondrial membrane compromise, mitochondrial proliferation, and damaged sarcomeres, while mitochondria in brain cerebrum and cerebellum were morphologically normal. Substantial depletion of oxidative phosphorylation (OXPHOS) Complex I specific activities was observed in heart (87% reduction in mean, p = 0.02) and skeletal muscle (98% reduction...

  • mitochondrial toxicity in fetal Erythrocebus patas monkeys exposed transplacentally to zidovudine plus lamivudine
    AIDS Research and Human Retroviruses, 2004
    Co-Authors: Mariana Gerschenson, Andrea Ceresa, Jaclyn A Shaw, Vi Nguyen, Ember L. Ewings, Kunio Nagashima, Marisa St Claire, Steven W Harbaugh, Jeffrey W Harbaugh, Ofelia A Olivero
    Abstract:

    This study was designed to investigate fetal mitochondrial toxicity in Erythrocebus patas monkeys exposed in utero to zidovudine (AZT) and lamivudine (3TC), and taken at term. Pregnant patas monkeys were given a daily dose of 40 mg AZT (86% of the human daily dose, based on body weight), for the last 10 weeks (50%) of gestation, and a daily dose of 24 mg 3TC (84% of the human daily dose, based on body weight) for the last 4 weeks of gestation. At term, AZT was found to be incorporated into fetal mitochondrial DNA from skeletal muscle, liver, kidney, and placenta. By transmission electron microscopy (EM) drug-exposed fetal cardiac and skeletal muscle cells showed mitochondrial membrane compromise, mitochondrial proliferation, and damaged sarcomeres, while mitochondria in brain cerebrum and cerebellum were morphologically normal. Substantial depletion of oxidative phosphorylation (OXPHOS) Complex I specific activities was observed in heart (87% reduction in mean, p = 0.02) and skeletal muscle (98% reduction in mean, p = 0.002) from drug-exposed fetuses, compared to unexposed fetuses. In addition Complex IV activity was highly depleted (85% reduction in mean, p = 0.004) in skeletal muscle from the drug-exposed fetuses (p = 0.004). Brain cerebrum and cerebellum showed no statistically significant OXPHOS changes with drug exposure. Mitochondrial DNA quantity was substantially depleted (>50%) in heart, skeletal muscle, cerebellum, and cerebrum from drug-exposed fetuses compared to unexposed controls. Overall, the data indicate that significant mitochondrial damage was observed at birth in monkey fetuses exposed in utero to AZT plus 3TC in a human-equivalent dosing protocol.

  • chronic stavudine exposure induces hepatic mitochondrial toxicity in adult Erythrocebus patas monkeys
    Journal of Human Virology, 2001
    Co-Authors: Mariana Gerschenson, V T Nguyen, St Claire Mc, S W Harbaugh, J W Harbaugh, Laurie A. Proia, M C Poirier
    Abstract:

    OBJECTIVES: To understand the mitochondrial mechanisms underlying the lactic acidosis and hepatic steatosis seen in some HIV-1-infected individuals after long-term stavudine (d4T) exposure, we have explored mitochondrial integrity in adult monkeys (Erythrocebus patas) given a daily human equivalent dose of d4T for 78 days. STUDY DESIGN/METHODS: Three Erythrocebus patas (patas) monkeys were given 3 mg d4T orally twice daily (total 6 mg d4T), or approximately 1.2 mg d4T/kg body weight per day, for 78 days and compared with 3 unexposed animals. Blood taken from controls and from treated monkeys before and after drug exposure was subjected to a complete clinical chemistry profile. Liver and skeletal muscles were examined for oxidative phosphorylation enzyme specific activities, mitochondrial deoxyribonucleic acid (mtDNA) quantity by slot blot, and mtDNA integrity by Southern blot. RESULTS: Clinical chemistry assays demonstrated few significant differences; however, one d4T-exposed monkey had a serum lactate of 8.1 mmol/L after 78 days of oral d4T ingestion. Specific activities of oxidative phosphorylation Complexes I, II, and IV were significantly altered in both livers and skeletal muscles from the d4T-exposed animals, compared with the controls (p < or = 0.05). Significant depletion of mitochondrial DNA was observed in livers of drug-exposed monkeys, but not in skeletal muscle (p < or = 0.05). Further examination of liver DNA by Southern blot confirmed hepatic mtDNA depletion in drug exposed animals. CONCLUSIONS: The data suggest that direct examination of the liver may be required to elucidate clinical d4T-induced hepatotoxicity related to mitochondrial damage.

  • fetal mitochondrial heart and skeletal muscle damage in Erythrocebus patas monkeys exposed in utero to 3 azido 3 deoxythymidine
    AIDS Research and Human Retroviruses, 2000
    Co-Authors: Mariana Gerschenson, S W Harbaugh, J W Harbaugh, Stephen W Erhart, Catherine Y Paik, Boris Skopets, Wing Quan, Kunio Nagashima, Marisa St Claire, Miriam C. Poirier
    Abstract:

    3'-azido-3'-deoxythymidine (AZT) is given to pregnant women positive for the human immunodeficiency virus type 1 (HIV-1) to reduce maternal–fetal viral transmission. To explore fetal mitochondrial consequences of this exposure, pregnant Erythrocebus patas monkeys were given daily doses of 1.5 mg (21% of the human daily dose) and 6.0 mg (86% of the human daily dose) of AZT/kg body weight (bw), for the second half of gestation. At term, electron microscopy of fetal cardiac and skeletal muscle showed abnormal and disrupted sarcomeres with myofibrillar loss. Some abnormally shaped mitochondria with disrupted cristae were observed in skeletal muscle myocytes. Oxidative phosphorylation (OXPHOS) enzyme assays showed dose-dependent alterations. At the human-equivalent dose of AZT (6 mg of AZT/kg bw), there was an ~85% decrease in the specific activity of NADH dehydrogenase (complex I) and three- to sixfold increases in specific activities of succinate dehydrogenase (complex II) and cytochrome-c oxidase (complex I...

Beth Autin - One of the best experts on this subject based on the ideXlab platform.

Angelique Male - One of the best experts on this subject based on the ideXlab platform.