African trypanosomiasis is caused by the protozoan parasite Trypanosoma brucei, transmitted between mammals by the bite of a tsetse. It has been recently shown that parasites accumulate in large numbers in various organs and tissues, including the mouse testis. Whether parasites are protected from the immune system in the male reproductive organ or can be transmitted through sexual route remains unknown. Here we show that parasites can be detected by fine needle aspiration cytology of the male reproductive system in mice, and histopathological analysis revealed that T. brucei accumulates in the stroma of the epididymis, epididymal adipose tissue and fibrous tunics of the testis. No parasites were found in the lumen of intact epididymal ducts or seminiferous tubules of the testis, indicating that the large majority of the parasites are not located in immune-privileged sites. In fact, these parasites are associated with marked inflammatory cell infiltration, parasite degeneration, and severe tissue damage and rupture of epididymal ducts, which may be related with reduced fertility. Overall, we show that just like in the bloodstream and most other tissues, in the male reproductive organs, T. brucei are exposed to a strong immune response. The detection of a very high number of parasites in this organ and its accessibility opens the possibility of using fine needle aspiration cytology as a complementary diagnostic tool in Animal African Trypanosomiasis.

Antigenic variation in Trypanosoma brucei relies on periodic switching of variant surface glycoproteins (VSGs), which are transcribed monoallelically by RNA polymerase I from one of about 15 bloodstream expression sites (BES). Chromatin of the actively transcribed BES is depleted of nucleosomes, but it is unclear if this open conformation is a mere consequence of a high rate of transcription, or whether it is maintained by a transcription-independent mechanism. Using an inducible BES-silencing reporter strain, we observed that chromatin of the active BES remains open for at least 24 hours after blocking transcription. This conformation is independent of the cell-cycle stage, but dependent upon TDP1, a high mobility group box protein. For two days after BES silencing, we detected a transient and reversible derepression of several silent BESs within the population, suggesting that cells probe other BESs before commitment to one, which is complete by 48 hours. FACS sorting and subsequent subcloning confirmed that probing cells are switching intermediates capable of returning to the original BES, switch to the probed BES or to a different BES. We propose that regulation of BES chromatin structure is an epigenetic mechanism important for successful antigenic switching.

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Introduction Gas stations present several workplace hazards of physical, chemical, ergonomic, biological and psychosocial nature. Repetitive movements, lifting heavy items and poor posture are among the ergonomic hazards, which can lead to various pathologies in the short and long term. Musculoskeletal disorders are one of the most common work-related diseases, contributing to loss of quality of life and decrease labor productivity. Clinical Case Report The authors describe the case of a 54-year-old female worker, a gas station operator, who developed pain and paresthesia in her right hand. She was observed in Occupational Health medical exam and the diagnostic hypothesis of carpal tunnel syndrome was proposed. After the orthopedic examination, the diagnosis was confirmed with surgery indication, which occurred without complications. Upon returning to work, the occupational disease was participated, being recognized afterwards because the linkage between her pathology and professional activity was confirmed. Discussion/Conclusion With this article we intend to alert to the need of notifying occupational diseases whenever there is an association between the activity and the pathology presented, as well as to emphasize the multiplicity of risk factors existing in gas stations, being essential the implementation of surveillance programs to promote workers’ health. KEYWORDS: Carpal tunnel syndrome, Musculoskeletal diseases, Filling station, Occupational health, Occupational disease.

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