The anconeus is a small muscle situated at the elbow. Although the anconeus is active during elbow extension its importance for the movement is probably small. It could work as an elbow stabilizer. The object of this study was to investigate some anatomic and architectural characteristics of the anconeus, in the hope of shedding light on its function. We studied twenty adult cadaveric specimens. The anconeus originates by the lateral epicondyle of the humerus and inserts along the proximal ulna. The superficial shape of the anconeus is triangular. Tridimensionally the anconeus resembles a hemisected rectangular-based pyramid, with the base at the ulna and apex at the lateral epicondyle. The muscle fibers arise obliquely from the tendinous expansion and inserts at the ulna. Thus, the architecture of the anconeus is penniform, an architecture able to produce more force then displacement. The design index of 0.3 also suggests a force muscle.
SUMMARY:The aim of the present study was to test the hypothesis that the application of fluoxetine -a highly selective serotonin reuptake inhibitor (SSRI) -in rats during the suckling period induces changes in testicular development. Groups of newborn male rats were randomly assigned with different doses of fluoxetine 24 hours after birth. Each litter stayed with its respective mother during 21 days. Body weight (BW) was measured daily from the 1st -21 st day to calculate daily doses of fluoxetine. 5 mg (T1), 10 mg (T2) 20 mg (T3) or deionized water, were injected intraperitoneally. On the 21 st day, animals were heparinized, anesthetized and blood was collected by cardiac puncture to determine by radioimmunoassay the follicle stimulating hormone (FSH) levels. Testis were removed, weighed, and processed for morphometric analysis. Fluoxetine groups presented decreased body and testicular weight when compared with the control group on the 21 st day. Our findings show that the manipulation of the serotoninergic system with fluoxetine during the critical period of testicular development alters the Sertoli cell population and all testicular parameters related to this cell.
-Endogenous opioid peptides play an important role in the ontogenesis of the functional and morphological parameters of the seminiferous epithelium. The aim of this study was to evaluate the effects of neonatal manipulations with naloxone, an opioid antagonist, on the population of Sertoli cells and on sperm production in adult rats. Rats were assigned to receive 8 µg per gram of body weight twice a day with interval of 8 h of naloxone and they were compared to a control group receiving saline. Naloxone groups presented the following findings when compared to the control group: increased body weight from the 2nd to the 27th day; a smaller seminiferous epithelium height, smaller seminiferous tubule diameter, increased number of Sertoli cells and daily sperm production per testis, increased daily sperm production per gram per testis and increased total length of the seminiferous tubule of the treated groups. According to our study, the neonatal treatment with naloxone during the critical period of testis development was able to change the proliferative dynamics of Sertoli cells by an intra and/or extra testicular blockage of opioid receptors, confirming the direct relation between the number of Sertoli cells and the number of spermatozoids. naloxone / testis development / Sertoli cells / sperm production / rats
Os distúrbios da transmissão neuromuscular constituem grupo heterogêneo de doenças que podem ser congênitas auto-imunes ou tóxicas 1 . Na miastenia grave, o mais comum, é um distúrbio auto-imune que se caracteriza por um defeito pós-sináptico na transmissão neuromuscular 2 e apresenta dois pontos cardinais: debilidade muscular e fadigabilidade 3 . Os testes de estimulação repetitiva (TER) são técni-cas eletrofisiológicas simples e muito úteis para auxiliar o diagnóstico dos distúrbios da transmissão neuromuscular 4,5 . Os TER devem ser solicitados sempre que se suspeita de miastenia grave, botulismo, sín-drome miastênica de Lambert-Eaton ou, em geral, para qualquer paciente que apresente fatigabilidade, fraqueza proximal, disfagia, disartria ou anormalidades oculares 6,7 . No TER a 3 Hz, a técnica eletrodiagnóstica mais comumente utilizada para o diagnóstico de miastenia grave, registra-se o potencial de RESUMO -Objetivo: Mapear a área de placa motora do músculo ancôneo para definir a melhor localização dos eletrodos de registro em testes de estimulação repetitiva (TER) no diagnóstico dos distúrbios da transmissão neuromuscular. Método: Registramos o potencial de ação composto do músculo ancôneo sobre a pele que o recobre, após estimulação do ramo que o inerva. Analisando as formas de onda registradas em cada ponto da pele foi possível definir a área de placa. Resultados: A área de placa motora do ancôneo é uma linha paralela à borda da ulna. O melhor local de colocação do eletrodo "ativo" de registro situa-se cerca de 2 cm distal ao olécrano e 1 cm lateral à borda da ulna. Conclusão: A realização de TER no mús-culo ancôneo é simples e bem tolerada. Com a estimulação do ancôneo o antebraço praticamente não se move, sendo o procedimento livre de artefatos de movimento.PALAvRAS-CHAvE: músculo ancôneo, área de placa motora, teste de estimulação repetitiva, distúrbios da transmissão neuromuscular, miastenia grave.Repetitive stimulation test on the anconeus muscle for the diagnosis of myasthenia gravis: the mapping of its motor end-plate area ABSTRACT -Purpose: To map the motor end-plate area of the anconeus muscle and define the best place for positioning the recording electrodes in repetitive stimulation tests (RST) for the diagnosis of neuromuscular transmission disorders. Method: The compound muscle action potential of the anconeus was recorded after stimulating the motor branch of the radial nerve that innervates it. By analyzing the waveforms registered at each point of the skin we were able to define the motor end-plate area. Results: The motor end-plate area of the anconeus is a line parallel to the ulna border. The best place for placing the "active" recording electrode is about 2cm distal to the olecranon and 1 cm lateral to the border of the ulna. Conclusion: Performing RST in the anconeus muscle is simple and well tolerated. Stimulation of the anconeus almost doesn't move the forearm and the procedure is virtually free of movement artifacts.
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