AIMTo prove the hypothesis that cavernosus muscles' contraction during coitus affects the reflex contraction of anal sphincters.

METHODSElectromyographic response of external and internal anal sphincters to ischiocavernosus and bulbocavernosus muscle stimulation was studied in 17 healthy volunteers (10 men, 7 women, mean aged 38.3+/-11.6 years). The test was repeated after individual anesthetization of anal sphincters and the two cavernosus muscles, and after using saline instead of lidocaine.

RESULTSUpon stimulation of each of the two cavernosus muscles, external and internal anal sphincters recorded increased electromyographic activity. Anal sphincters did not respond to stimulation of the anesthetized cavernosus muscles nor did anesthetized anal sphincters respond to cavernosus muscles' stimulation. Saline infiltration did not affect anal sphincteric response to cavernosal muscles' stimulation.

CONCLUSIONCavernosus muscles' contraction is suggested to evoke anal sphincteric contraction, which seems to be a reflex and mediated through the "Cavernoso-anal reflex". Anal sphincteric contraction during coitus presumably acts to close the anal canal to thwart flatus or fecal leak.

Adult ; Anal Canal ; physiology ; Electric Stimulation ; Electromyography ; Female ; Humans ; Male ; Middle Aged ; Muscle, Skeletal ; physiology ; Reference Values ; Reflex ; physiology

Introduction: Dengue fever is caused by the dengue virus that is transmitted via Aedes mosquitoes. The lifecycle of Aedes mosquitoes is affected by the local climate (rainfall) which influences dengue transmission. Sabah is one of the states that is laden with a high incidence rate of dengue in Malaysia and the condition seems to have worsened with sudden, multiple outbreaks occurring in the year 2016. Methods: An ecological analysis was conducted in Keningau, Sabah to analyse dengue case patterns and distribution over a 5-year period and to exhibit the correlation between rainfall, larval indices, dengue incidences, and outbreaks. Results: Significant cross-correlation analysis (CCF) was discovered between rainfall and Aedes index at lag number 5 with a correlation coefficient of 0.151 (±0.063) as well as between rainfall and Breteau Index at lag number 5 with a correlation coefficient of 0.143 (±0.063). However, no significant cross-correlation analysis was found between Aedes index and dengue incidences. Associations were also seen between larval indices and outbreak cases. Conclusion: This study showed an increase of Aedes and Breteau Indices to susceptibility level five weeks after rainfall which increases the risk of dengue transmission.