851 resultados para African Christianity


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BACKGROUND Skin cancer is rare among Africans and albinism is an established risk for skin cancer in this population. Ultraviolet radiation is highest at the equator and African albinos living close to the equator have the highest risk of developing skin cancers. METHODS This was a retrospective study that involved histological review of all specimens with skin cancers from African albinos submitted to The Regional Dermatology Training Center in Moshi, Tanzania from 2002 to 2011. RESULTS A total of 134 biopsies from 86 patients with a male to female ratio of 1:1 were reviewed. Head and neck was the commonest (n = 75, 56.0%) site affected by skin cancers. Squamous cell carcinoma (SCC) was more common than basal cell carcinoma (BCC) with a ratio of 1.2:1. Only one Acral lentiginous melanoma was reported. Majority (55.6%) of SCC were well differentiated while nodular BCC (75%) was the most common type of BCC. CONCLUSIONS Squamous cell carcinoma is more common than basal cell carcinoma in African albinos.

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Eukaryotic cells are compartmentalized into membrane-bound organelles in order to provide sheltered reaction rooms for various specific processes. Organelles are not randomly distributed in a cell or operate isolated from each other. At the contrary — some organelles are closely linked and their functions are tightly orchestrated. The most well-known example of two such organelles acting in concert are the ER and the mitochondrion that work together in order to coordinate cellular lipid biosynthesis, maintain Ca2+-homeostasis, regulate mitochondrial division and control mitochondrial/ER shape as well as to synchronize the movement of these organelles within a cell. To study the mitochondrion and its interface to the ER requires a simplified mitochondrial system. African trypanosomes represent such a system. The unicellular parasite that causes devastating diseases in humans and animals has only one large mitochondrion that does not undergo fission/fusion events except for the context of cell division. Moreover, mitochondrial functions and morphology are highly regulated throughout the life cycle of the protozoan. Central to the understanding of how mitochondria control their morphology, communicate with their surroundings and manage exchange of metabolites and transport of biopolymers (proteins, RNAs) is the mitochondrial outer membrane (MOM), as the MOM defines the boundary of the organelle. Recently, we have purified the MOM of T. brucei and characterized its proteome using label-free quantitative mass spectrometry for protein abundance profiling in combination with statistical analysis. Our results show that the trypanosomal MOM proteome consists of 82 proteins, two thirds of which have never been associated with mitochondria before. Among these, we identified novel factors required to regulate mitochondrial morphology and the long-elusive protein import machinery of T. brucei. A comparison with the MOM proteome of yeast defines a set of 17 common proteins that are likely present in the mitochondrial outer membrane of all eukaryotes. One of these is the Miro-GTPase Gem1. In yeast, this Ca2+-EF-Hand containing polypeptide is thought to be involved in a protein complex that physically tethers the mitochondrion to the ER. Interestingly, a putative tethering complex in mammalian cells was linked to the mitochondrial fusion/fission machinery. Thus, the concept of a protein complex-mediated connection seems to be a general and conserved feature. We are currently investigating, if such a protein complex exists in T. brucei and if the trypanosomal Gem1 protein is involved. This ER-subdomain associated with mitochondria has been termed mitochondria-associated ER-membranes or MAM. The MAM has recently been implicated to play a key role in Alzheimer’s disease. It is therefore of broad and general interest to establish other eukaryotic model systems in order to investigate the MAM-MOM connection in more detail.

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Central to the understanding of how mitochondria control their morphology, communicate with their surroundings and manage exchange of metabolites and transport of biopolymers (proteins, RNAs) is the mitochondrial outer membrane (MOM), as the MOM defines the boundary of the organelle. Recently, we have purified the MOM of the mitochondrial model organism T. brucei and characterized its proteome. Our results show that the trypanosomal MOM proteome consists of 82 proteins. Among these, we identified novel factors required to regulate mitochondrial morphology and the long-elusive protein import machinery of T. brucei. A comparison with the MOM proteome of yeast defines a set of 17 common proteins that are likely present in the mitochondrial outer membrane of all eukaryotes. One of these is the Miro-GTPase Gem1. In yeast, this Ca2+-EF-Hand containing polypeptide is thought to be involved in a protein complex that physically tethers the mitochondrion to the ER. In mammalian cells, a putative tethering complex was linked to the mitochondrial fusion/fission machinery. Thus, the concept of a protein complex-mediated connection seems to be a general and conserved feature. We are currently investigating if such a protein complex exists in T. brucei and if the trypanosomal Gem1 protein is involved.

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This study investigated the attitudes and beliefs of pig farmers and hunters in Germany, Bulgaria and the western part of the Russian Federation towards reporting suspected cases of African swine fever (ASF). Data were collected using a web-based questionnaire survey targeting pig farmers and hunters in these three study areas. Separate multivariable logistic regression models identified key variables associated with each of the three binary outcome variables whether or not farmers would immediately report suspected cases of ASF, whether or not hunters would submit samples from hunted wild boar for diagnostic testing and whether or not hunters would report wild boar carcasses. The results showed that farmers who would not immediately report suspected cases of ASF are more likely to believe that their reputation in the local community would be adversely affected if they were to report it, that they can control the outbreak themselves without the involvement of veterinary services and that laboratory confirmation would take too long. The modelling also indicated that hunters who did not usually submit samples of their harvested wild boar for ASF diagnosis, and hunters who did not report wild boar carcasses are more likely to justify their behaviour through a lack of awareness of the possibility of reporting. These findings emphasize the need to develop more effective communication strategies targeted at pig farmers and hunters about the disease, its epidemiology, consequences and control methods, to increase the likelihood of early reporting, especially in the Russian Federation where the virus circulates

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Tropical forests are carbon-dense and highly productive ecosystems. Consequently, they play an important role in the global carbon cycle. In the present study we used an individual-based forest model (FORMIND) to analyze the carbon balances of a tropical forest. The main processes of this model are tree growth, mortality, regeneration, and competition. Model parameters were calibrated using forest inventory data from a tropical forest at Mt. Kilimanjaro. The simulation results showed that the model successfully reproduces important characteristics of tropical forests (aboveground biomass, stem size distribution and leaf area index). The estimated aboveground biomass (385 t/ha) is comparable to biomass values in the Amazon and other tropical forests in Africa. The simulated forest reveals a gross primary production of 24 tcha-1yr-1. Modeling above- and belowground carbon stocks, we analyzed the carbon balance of the investigated tropical forest. The simulated carbon balance of this old-growth forest is zero on average. This study provides an example of how forest models can be used in combination with forest inventory data to investigate forest structure and local carbon balances.