Radiotherapy is used to treat approximately 50% of all cancer patients, with varying success. The dose of ionizing radiation that can be given to the tumour is determined by the sensitivity of the ...surrounding normal tissues. Strategies to improve radiotherapy therefore aim to increase the effect on the tumour or to decrease the effects on normal tissues. These aims must be achieved without sensitizing the normal tissues in the first approach and without protecting the tumour in the second approach. Two factors have made such approaches feasible: namely, an improved understanding of the molecular response of cells and tissues to ionizing radiation and a new appreciation of the exploitable genetic alterations in tumours. These have led to the development of treatments combining pharmacological interventions with ionizing radiation that more specifically target either tumour or normal tissue, leading to improvements in efficacy.
Like humans, chimpanzees (
Pan troglodytes
) are well known for their vertebrate and invertebrate hunting, but they rarely scavenge. In contrast, while hunting and meat consumption became ...increasingly important during the evolution of the genus
Homo
, scavenging meat and marrow from carcasses of large mammals was also likely to be an important component of their subsistence strategies. Here, we describe a confrontational scavenging interaction between an adult male chimpanzee from the Issa Valley and a crowned eagle (
Stephanoaetus coronatus
), which resulted in the chimpanzee capturing and consuming the carcass of a juvenile bushbuck (
Tragelaphus scriptus
). We describe the interaction and contextualize this with previous scavenging observations from chimpanzees.
The metabolic phenotype of an organism depends on a complex regulatory network, which integrates the plethora of intrinsic and external information and prioritizes the flow of nutrients accordingly. ...Given the rise of metabolic disorders including obesity, a detailed understanding of this regulatory network is in urgent need. Yet, our level of understanding is far from completeness and complicated by the discovery of additional layers in metabolic regulation, such as the impact of the microbial community present in the gut on the hosts' energy storage levels. Here, we investigate the interplay between genome variation, diet and the gut microbiome in the shaping of a metabolic phenotype. For this purpose, we reared a set of fully sequenced wild type Drosophila melanogaster flies under basal and nutritionally challenged conditions and performed metabolic and microbiome profiling experiments. Our results introduce the fly as a model system to investigate the impact of genome variation on the metabolic response to diet alterations and reveal candidate single nucleotide polymorphisms associated with different metabolic traits, as well as metabolite-metabolite and metabolite-microbe correlations. Intriguingly, the dietary changes affected the microbiome composition less than anticipated. These results challenge the current view of a rapidly changing microbiome in response to environmental fluctuations.
Photodynamic Therapy in Oncology Triesscheijn, Martijn; Baas, Paul; Schellens, Jan H. M. ...
The oncologist (Dayton, Ohio),
October 2006, Volume:
11, Issue:
9
Journal Article
Peer reviewed
Open access
Learning Objectives
After completing this course, the reader will be able to:
Discuss the safety and side effects of PDT.
Identify appropriate indications for PDT.
Explain the choice of PDT over ...other treatment modalities.
Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Photodynamic therapy (PDT) is increasingly being recognized as an attractive, alternative treatment modality for superficial cancer. Treatment consists of two relatively simple procedures: the administration of a photosensitive drug and illumination of the tumor to activate the drug. Efficacy is high for small superficial tumors and, except for temporary skin photosensitization, there are no long‐term side effects if appropriate protocols are followed. Healing occurs with little or no scarring and the procedure can be repeated without cumulative toxicity. Considering the efficacy and lack of long‐term toxicity of PDT, and the fact that the first treatment of cancer with PDT was done more than 100 years ago, one might expect that this treatment had already become an established therapy. However, PDT is currently offered in only a few selected centers, although it is slowly gaining acceptance as an alternative to conventional cancer therapies. Here, we show the developmental steps PDT underwent and summarize the current clinical applications. The data show that, when properly used, PDT is an effective alternative treatment option in oncology.
Fission-fusion societies are social systems in which individuals belonging to the same community are rarely all together but rather spend most of their time in temporary parties. This flexible social ...organization is assumed to be an adaptation that balances advantages and costs of group living in a fluid way as resources and constraints shift through space and time. It has been argued that this flexibility freed hominins from the foraging constraints caused by living in large groups. Given their close genetic relationship to humans and because they represent the classic case of a fission-fusion society, chimpanzees have often been used as referential models to understand human social evolution. Determinants of chimpanzee party size have been widely studied for decades across several communities. However, we lack data from open and dry sites—which closely resemble those reconstructed for Plio-Pleistocene hominins—on communities that potentially face similar environmental constraints as early hominins did. We investigated chimpanzee (Pan troglodytes schweinfurthii) grouping patterns on a recently habituated community living in the savanna-woodland mosaic landscape of the Issa Valley, western Tanzania, by following chimpanzees daily and recording party size every hour. Our results revealed that party size at Issa 1) followed seasonal fluctuations in food availability, 2) increased in the presence of swollen females, and 3) was higher in open vegetation, which potentially presents a high predation risk. Furthermore, we found the Issa community to be highly cohesive compared with the majority of other communities, possibly due to a combination of its small size and potential threats characterizing its home range. Our study fills a gap in our knowledge of chimpanzee sociality by exploring grouping pattern determinants in an East African understudied biome and highlights what elements of early hominin social behavior may have evolved in Late Pliocene landscapes.
Many primates show sex differences in behavior, particularly social behavior, but also tool use for extractive foraging. All great apes learn to build a supportive structure for sleep. Whether sex ...differences exist in building, as in extractive foraging, is unknown, and little is known about how building skills develop and vary between individuals in the wild. We therefore aimed to describe the nesting behavior of savanna chimpanzees (
Pan troglodytes verus
) in Fongoli, Senegal to provide comparative data and to investigate possible sex or age differences in nest building behaviors and nest characteristics. We followed chimpanzee groups to their night nesting sites to record group (55 nights) and individual level data (17 individuals) on nest building initiation and duration (57 nests) during the dry season between October 2007 and March 2008. We returned the following morning to record nest and tree characteristics (71 nests built by 25 individuals). Fongoli chimpanzees nested later than reported for other great apes, but no sex differences in initiating building emerged. Observations were limited but suggest adult females and immature males to nest higher, in larger trees than adult males, and adult females to take longer to build than either adult or immature males. Smaller females and immature males may avoid predation or access thinner, malleable branches, by nesting higher than adult males. These differences suggest that sex differences described for chimpanzee tool use may extend to nest building, with females investing more time and effort in constructing a safe, warm structure for sleep than males do.
All metazoans are colonized by a complex and diverse set of microorganisms. The microbes colonize all parts of the body and are especially abundant in the gastrointestinal tract, where they ...constitute the gut microbiome. The fruit fly Drosophila melanogaster turned out to be an exquisite model organism to functionally test the importance of an intact gut microbiome. Still, however, fundamental questions remain unanswered. For example, it is unknown whether a fine-tuned regionalization of the gut microbiome exists and how such a spatial organization could be established. In order to pave the way for answering this question, we generated an optimized and adapted fluorescence in situ hybridization (FISH) protocol. We focused on the detection of the two major Drosophila gut microbiome constituting bacteria genera: Acetobacter and Lactobacillus. FISH allows to detect the bacteria in situ and thus to investigate their spatial localization in respect to the host as well as to other microbiome members. We demonstrate the applicability of the protocol using a diverse set of sample types.
Human disturbance is an ongoing threat to many wildlife species, manifesting as habitat destruction, resource overuse, or increased disease exposure, among others. With increasing human: non-human ...primate (NHP) encounters, NHPs are increasingly susceptible to human-introduced diseases, including those with parasitic origins. As such, epidemiology of parasitic disease is becoming an important consideration for NHP conservation strategies. To investigate the relationship between parasite infections and human disturbance we studied yellow baboons (Papio cynocephalus) living outside of national park boundaries in western Tanzania, collecting 135 fresh faecal samples from nine troops occupying areas with varying levels of human disturbance. We fixed all samples in 10% formalin and later evaluated parasite prevalence and abundance (of isotrichid ciliates and Strongylida). We identified seven protozoan and four helminth taxa. Taxa showed varied relationships with human disturbance, baboon troop size and host age. In four taxa, we found a positive association between prevalence and troop size. We also report a trend towards higher parasite prevalence of two taxa in less disturbed areas. To the contrary, high levels of human disturbance predicted increased abundance of isotrichid ciliates, although no relationship was found between disturbance and Strongylida abundance. Our results provide mixed evidence that human disturbance is associated with NHP parasite infections, highlighting the need to consider monitoring parasite infections when developing NHP conservation strategies.
Understanding the ecological factors that drive animal density patterns in time and space is key to devising effective conservation strategies. In Tanzania, most chimpanzees (~75%) live outside ...national parks where human activities threaten their habitat's integrity and connectivity. Mahale Mountains National Park (MMNP), therefore, is a critical area for chimpanzees (Pan troglodytes schweinfurthii) in the region due to its location and protective status. Yet, despite its importance and long history of chimpanzee research (>50 years), a park-wide census of the species has never been conducted. The park is categorized as a savanna-woodland mosaic, interspersed with riparian forest, wooded grassland, and bamboo thicket. This heterogeneous landscape offers an excellent opportunity to assess the ecological characteristics associated with chimpanzee density, a topic still disputed, which could improve conservation plans that protect crucial chimpanzee habitat outside the park. We examined the influence of fine-scale vegetative characteristics and topographical features on chimpanzee nest density, modeling nest counts using hierarchical distance sampling. We counted 335 nests in forest and woodland habitats across 102 transects in 13 survey sites. Nests were disproportionately found more in or near evergreen forests, on steep slopes, and in feeding tree species. We calculated chimpanzee density in MMNP to be 0.23 ind/km2, although density varied substantially among sites (0.09-3.43 ind/km2). Density was associated with factors related to the availability of food and nesting trees, with topographic heterogeneity and the total basal area of feeding tree species identified as significant positive predictors. Species-rich habitats and floristic diversity likely play a principal role in shaping chimpanzee density within a predominately open landscape with low food abundance. Our results provide valuable baseline data for future monitoring efforts in MMNP and enhance our understanding of this endangered species' density and distribution across Tanzania.
Objectives
Primates that live in predominantly forested habitats and open, savanna mosaics should exhibit behavioral responses to differing food distributions and weather. We compared ecological ...constraints on red‐tailed monkey ranging behavior in forest and savanna mosaic environments. Intraspecific variation in adaptations to these conditions may reflect similar pressures faced by hominins during the Plio‐Pleistocene.
Methods
We followed six groups in moist evergreen forest at Ngogo (Uganda) and one group in a savanna‐woodland mosaic at the Issa Valley (Tanzania). We used spatial analyses to compare home range sizes and daily travel distances (DTD) between sites. We used measures of vegetation density and phenology to interpolate spatially explicit indices of food (fruit, flower, and leaves) abundance. We modeled DTD and range use against food abundance. We modeled DTD and at Issa hourly travel distances (HTD), against temperature and rainfall.
Results
Compared to Issa, monkeys at Ngogo exhibited significantly smaller home ranges and less variation in DTD. DTD related negatively to fruit abundance, which had a stronger effect at Issa. DTD and HTD related negatively to temperature but not rainfall. This effect did not differ significantly between sites. Home range use did not relate to food abundance at either site.
Conclusions
Our results indicate food availability and thermoregulatory constraints influence red‐tailed monkey ranging patterns. Intraspecific variation in home range sizes and DTD likely reflects different food distributions in closed and open habitats. We compare our results with hypotheses of evolved hominin behavior associated with the Plio‐Pleistocene shift from similar closed to open environments.
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