146 research outputs found

    Functions of Intermittent Locomotion in Mustached Tamarins (Saguinus mystax)

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    Many animals interrupt their moving with brief pauses, which appear to serve several different functions. We examined the function of such intermittent locomotion in wild living mustached tamarins (Saguinus mystax), small arboreal New World primates that form mixed-species groups with saddleback tamarins (Saguinus fuscicollis). We investigated how different environmental and social factors affect pausing during locomotion and used these data to infer the function of this behavior. As measures of intermittent locomotion, we used percentage of time spent pausing and pause rate. We considered 3 possible functions that are not mutually exclusive: increased endurance, route planning, and antipredator vigilance. Mustached tamarins spent on average (mean ± SE) 55.1 ± 1.0% of time pausing, which makes effective resource exploitation more time consuming and needs to be outweighed by correspondingly large benefits. Percentage of time spent pausing decreased in larger mixed-species groups vs. smaller mixed-species groups and decreased with height and in monkeys carrying infants. It was not affected by sex, age, spatial arrangement, or single-species group size. Pause rate increased in individuals traveling independently compared to those traveling in file, but was not affected by other factors. The group size effect in mixed-species groups lends support to the notion that pausing during locomotion is an antipredator tactic that can be reduced in the increased safety of larger groups, but other results suggest that additional functions, particularly route planning, are also of great importance. Benefits in terms of predator confusion and group movement coordination are also likely to play a role and remain a topic for further research

    Zoledronic acid in metastatic chondrosarcoma and advanced sacrum chordoma: two case reports

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    <p>Abstract</p> <p>Introduction</p> <p>Chondrosarcomas and chordomas are usually chemoresistant bone tumors and may have a poor prognosis when advanced. They are usually associated with worsening pain difficult to control.</p> <p>Patients and Methods</p> <p>Zoledronic acid was used in a 63-year-old man with metastatic chondrosarcoma and in a 66-year-old woman with a diagnosis of sacrum chordoma both reporting severe pain related to tumor.</p> <p>Results</p> <p>In the first case, zoledronic acid was able to maintain pain control despite disease progression following chemotherapy, in the other case, zoledronic acid only produced significant clinical benefit.</p> <p>Conclusion</p> <p>Control of pain associated with bone tumors such as chondrosarcoma and chondroma may significantly improve from use of zoledronic acid, independently from tumor response to other treatments. Evaluation on larger series are needed to confirm the clinical effect of this bisphosphonate on such tumors.</p

    Reproductive failure, possible maternal infanticide, and cannibalism in wild moustached tamarins, Saguinus mystax

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    Maternal infanticide in wild non-human primates has only been reported twice. In this paper, we report a possible new case of infanticide and cannibalism within a series of four successive reproductive failures in wild moustached tamarins, Saguinus mystax. Necropsy and genetic analyses of the corpses enabled us to rule out any pathology, and to determine paternity. The mother was seen biting and then eating the head of its own infant during a period when another female was pregnant and gave birth just 1 month later. Before that, the perpetrator had given birth to twins three times successfully when four to five adult and subadult males were present in the group. Although we do not know for certain that the infant was alive when the mother started biting it, our field observations preceding the event suggest it probably was. The possible infanticide case and the two cases of births and early death of the infants occurred while only two to three adult males were present in the group. This could be the second case of maternal infanticide reported in the genus Saguinus and the similar circumstances suggest a common pattern. We discuss these events in the light of the different functional explanations of infanticide and conclude that parental manipulation was the most likely: the mother could have terminated the investment in offspring that had low chances of survival in a group with low availability of helpers

    Influences on gum feeding in primates

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    This chapter reviews the factors that may affect patterns of gum feeding by primates. These are then examined for mixed-species troops of saddleback (S. fuscicollis) and mustached (S. mystax) tamarins. An important distinction is made between gums produced by tree trunks and branches as a result of damage and those produced by seed pods as part of a dispersal strategy as these may be expected to differ in their biochemistry. Feeding on fruit and Parkia seed pod exudates was more prevalent in the morning whereas other exudates were eaten in the afternoon. This itinerary may represent a deliberate strategy to retain trunk gums in the gut overnight, thus maximising the potential for microbial fermentation of their β-linked oligosaccharides. Both types of exudates were eaten more in the dry than the wet season. Consumption was linked to seasonal changes in resource availability and not the tamarins’ reproductive status pro-viding no support for the suggestion that gums are eaten as a pri-mary calcium source in the later stages of gestation and lactation. The role of availability in determining patterns of consumption is further supported by the finding that dietary overlap for the trunk gums eaten was greater between species within mixed-species troops within years than it was within species between years. These data and those for pygmy marmosets (Cebuella pygmaea) suggest that patterns of primate gummivory may reflect the interaction of prefer-ence and availability for both those able to stimulate gum production and those not

    Building Babies - Chapter 16

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    In contrast to birds, male mammals rarely help to raise the offspring. Of all mammals, only among rodents, carnivores, and primates, males are sometimes intensively engaged in providing infant care (Kleiman and Malcolm 1981). Male caretaking of infants has long been recognized in nonhuman primates (Itani 1959). Given that infant care behavior can have a positive effect on the infant’s development, growth, well-being, or survival, why are male mammals not more frequently involved in “building babies”? We begin the chapter defining a few relevant terms and introducing the theory and hypotheses that have historically addressed the evolution of paternal care. We then review empirical findings on male care among primate taxa, before focusing, in the final section, on our own work on paternal care in South American owl monkeys (Aotus spp.). We conclude the chapter with some suggestions for future studies.Deutsche Forschungsgemeinschaft (HU 1746/2-1) Wenner-Gren Foundation, the L.S.B. Leakey Foundation, the National Geographic Society, the National Science Foundation (BCS-0621020), the University of Pennsylvania Research Foundation, the Zoological Society of San Dieg

    Constitutive Expression of TNF-Related Activation-Induced Cytokine (TRANCE)/Receptor Activating NF-κB Ligand (RANK)-L by Rat Plasmacytoid Dendritic Cells

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    Plasmacytoid dendritic cells (pDCs) are a subset of DCs whose major function relies on their capacity to produce large amount of type I IFN upon stimulation via TLR 7 and 9. This function is evolutionary conserved and place pDC in critical position in the innate immune response to virus. Here we show that rat pDC constitutively express TNF-related activation-induced cytokine (TRANCE) also known as Receptor-activating NF-κB ligand (RANKL). TRANCE/RANKL is a member of the TNF superfamily which plays a central role in osteoclastogenesis through its interaction with its receptor RANK. TRANCE/RANK interaction are also involved in lymphoid organogenesis as well as T cell/DC cross talk. Unlike conventional DC, rat CD4high pDC were shown to constitutively express TRANCE/RANKL both at the mRNA and the surface protein level. TRANCE/RANKL was also induced on the CD4low subsets of pDC following activation by CpG. The secreted form of TRANCE/RANKL was also produced by rat pDC. Of note, levels of mRNA, surface and secreted TRANCE/RANKL expression were similar to that observed for activated T cells. TRANCE/RANKL expression was found on pDC in all lymphoid organs as well blood and BM with a maximum expression in mesenteric lymph nodes. Despite this TRANCE/RANKL expression, we were unable to demonstrate in vitro osteoclastogenesis activity for rat pDC. Taken together, these data identifies pDC as novel source of TRANCE/RANKL in the immune system

    Distinct Roles of Bcl-2 and Bcl-Xl in the Apoptosis of Human Bone Marrow Mesenchymal Stem Cells during Differentiation

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    Background: Adult mesenchymal stem cells (MSCs) can be maintained over extended periods of time before activation and differentiation. Little is known about the programs that sustain the survival of these cells. Principal Findings: Undifferentiated adult human MSCs (hMSCs) did not undergo apoptosis in response to different cell death inducers. Conversely, the same inducers can readily induce apoptosis when hMSCs are engaged in the early stages of differentiation. The survival of undifferentiated cells is linked to the expression of Bcl-Xl and Bcl-2 in completely opposite ways. Bcl-Xl is expressed at similar levels in undifferentiated and differentiated hMSCs while Bcl-2 is expressed only in differentiated cells. In undifferentiated hMSCs, the down-regulation of Bcl-Xl is associated with an increased sensitivity to apoptosis while the ectopic expression of Bcl-2 induced apoptosis. This apoptosis is linked to the presence of cytoplasmic Nur 77 in undifferentiated hMSCs. Significance: In hMSCs, the expression of Bcl-2 depends on cellular differentiation and can be either pro- or anti-apoptotic. Bcl-Xl, on the other hand, exhibits an anti-apoptotic activity under all conditions

    Tumour macrophages as potential targets of bisphosphonates

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    Tumour cells communicate with the cells of their microenvironment via a series of molecular and cellular interactions to aid their progression to a malignant state and ultimately their metastatic spread. Of the cells in the microenvironment with a key role in cancer development, tumour associated macrophages (TAMs) are among the most notable. Tumour cells release a range of chemokines, cytokines and growth factors to attract macrophages, and these in turn release numerous factors (e.g. VEGF, MMP-9 and EGF) that are implicated in invasion-promoting processes such as tumour cell growth, flicking of the angiogenic switch and immunosuppression. TAM density has been shown to correlate with poor prognosis in breast cancer, suggesting that these cells may represent a potential therapeutic target. However, there are currently no agents that specifically target TAM's available for clinical use
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