ABSTRACT
Immobilization, used in clinical practice to treat traumatologic problems, causes changes in muscle, but it is not known whether changes also occur in nerves. We investigated the effects of immobilization on excitability and compound action potential (CAP) and the ultrastructure of the rat sciatic nerve. Fourteen days after immobilization of the right leg of adult male Wistar rats (n=34), animals were killed and the right sciatic nerve was dissected and mounted in a moist chamber. Nerves were stimulated at a baseline frequency of 0.2 Hz and tested for 2 min at 20, 50, and 100 Hz. Immobilization altered nerve excitability. Rheobase and chronaxy changed from 3.13±0.05 V and 52.31±1.95 µs (control group, n=13) to 2.84±0.06 V and 59.71±2.79 µs (immobilized group, n=15), respectively. Immobilization altered the amplitude of CAP waves and decreased the conduction velocity of the first CAP wave (from 93.63±7.49 to 79.14±5.59 m/s) but not of the second wave. Transmission electron microscopy showed fragmentation of the myelin sheath of the sciatic nerve of immobilized limbs and degeneration of the axon. In conclusion, we demonstrated that long-lasting leg immobilization can induce alterations in nerve function.
Subject(s)
Animals , Male , Action Potentials/physiology , Hindlimb/innervation , Immobilization/adverse effects , Nerve Degeneration/physiopathology , Sciatic Nerve/physiopathology , Chronaxy/physiology , Microscopy, Electron, Transmission , Myelin Sheath/physiology , Rats, Wistar , Time FactorsABSTRACT
A equipe odontológica está sujeita a condições que favorecemexposições ocupacionais a material biológico tais como aatuação na cavidade bucal - ambiente de pequenas dimensões,difícil acesso e colonizado por diversos microrganismos - e ouso de instrumentos perfurocortantes e equipamentos rotatóriosgeradores de respingos e aerossóis. Neste contexto, o objetivodeste trabalho foi identificar o perfil epidemiológico dos acidentesenvolvendo material biológico notificados na instituição.Foi delineado um estudo descritivo transversal considerandoas fichas (n=71) de registro de acidentes com material biológicoocorridos na instituição no período de março de 2002 a julhode 2008. Dentre os acidentes notificados, 91,6% ocorreram emestudantes, 4,2% em técnicos administrativos, 2,8% em professorese 1,4% em estagiários, sendo 64,8% dos acidentados dosexo feminino. Considerando que 31 notificações permaneceramcom dados incompletos, os demais acidentes (n=40) apresentaramo seguinte perfil: Exposição percutânea (34/85,0%) erespingos em mucosas (6/15,0%); A Área corporal mais atingidaforam as mãos (32/80,0%), e mucosas (6/15,0%); o materialbiológico envolvido foi o sangue e saliva (17/42,5%) e saliva(5/12,5%); houve prevalência do reencape (9/22,5%) e manuseio(7/17,5%) de agulha anestésica e da execução de procedimentoscirúrgicos (6/15,0%); A fonte era conhecida em 75,0% (n=30)dos acidentes. O uso de todos os equipamentos de proteção individualfoi apontado por 75,0% (n=30) dos respondentes e acobertura vacinal contra hepatite B por 95,0% (n=38), sendo que92,1% possuíam esquema vacinal completo e 50,0% conheciame eram respondedores ao Anti HBs. Conclui-se que o risco biológicoé iminente para a equipe odontológica e que é necessárioestabelecer um programa de educação permanente focado emestratégias de educação e prevenção de acidentes com materialbiológico e na sensibilização deste público quanto à importânciada notificação de acidentes, além de aperfeiçoar o sistema deregistro da CCIO.
The dental team is subject to conditions that foster occupationalexposure to biological material such as the performance inthe oral cavity - environment of small, difficult access and colonizedby various microorganisms - and the use of professionaltools and equipment rotary-generating sneezing and aerosols.In this context, the objective was to identify the epidemiologicalprofile of accidents involving biological material institution reported.A descriptive study was outlined considering the sheetscross (n= 71) for registration of accidents with biological materialoccurring in the institution during the period from March 2002to July 2008. Among the accidents, 91.6% occurred in students,4.2% in technical, administrative, 2.8% and 1.4% in teachers intrainees, with 64.8% of the injured were female. Consideringthat 31 notices remained with incomplete data, other accidents(n=40) showed the following: percutaneous exposure (34/85.0%)and sneezing in mucous (6 /15.0%); The body area most affectedwere the hands (32/80.0%), and as mucous (6/15.0%); thebiological material involved: there was the prevalence of bloodand saliva (17/42.5.0%), followed by saliva (5 /12.5%) and blood(3/7.5%), 4. Location of accident: there was a prevalence of reencape(9/22.5%) and handling (7/17.5%) of anesthetic needle andimplementation of surgical procedures (6/15.0%); 5. Situation ofthe patient source: source known in 75.0% (n=30) of accidents.The use of all equipment for individual protection was reportedby 75.0% (n=30) of respondents and immunization coverageagainst hepatitis B by 95.0% (n=38), and 92.1% had full immunizationschedule and 50.0% knew and were responsive to antiHBs. It was concluded that the biological risk is imminent forthe dental team and it is necessary to establish a program of continuingeducation focused on strategies for education and preventionof accidents with biological material and in this publicawareness about the importance of the notification of accidents,and improve the system of registration of CCIO.