Our findings indicate a specific role for the pelvic and perineal muscles during feminine micturition.

Temporal and coordinated activation of pelvic- (pubococcygeous) and perineal- (bulbospongiosus and ischiocavernosus) striated muscles occurs during micturition in female rabbits. We have hypothesized that the coordinated activation of pelvic and perineal muscles is modified during the micturition of young multiparous rabbits. Young virgin and multiparous female chinchilla rabbits were used to simultaneously record cystometrograms and electromyograms of the pubococcygeous, ischocavernosus, and bulbospongiosus muscles. Bladder function was assessed using standard urodynamic variables. The temporal coordination of pelvic- and perineal-striated muscle activity was changed in multiparous rabbits. The cystometrogram recordings were different than those obtained from virgin rabbits, as seen in alterations of the threshold volume, the residual volume, the voiding duration, and the maximum pressure. In rabbits, we find that multiparity causes uncoordinated activity of pubococcygeous, ischiocavernosus, and bulbospongiosus muscles and modifies the urodynamics.

In women, birth trauma can result in altered anatomy of supporting structures of the pelvic floor and in the development of urinary incontinence. The goal of this study was to investigate the association between parturition and the morphology and function of perineal and pelvic muscles in the female rabbit. In ten nulliparous and ten multiparous same-age females, we investigated morphological, histological (n = 5 females/group), and contractile characteristics (n = 5 females/group) of the perineal bulbospongiosus (Bsm) and the pelvic pubococcygeus (Pcm) muscles. Bsm and Pcm muscles of multiparous females were significantly lighter, they had a smaller cross-sectional fiber area, and developed significantly lower twitch and tetanic tension force in response to electrical stimulation than muscles of nulliparous females. In female rabbits, multiparity is associated with potentially pathological changes in the morphological and functional characteristics of these perineal and pelvic muscles, possibly as a result of stretching during parturition.

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Is erythrocyte size a strategy to avoid hypoxia in Sceloporus torquatus? Field evidence 4 5 Abstract 6 This study examined changes of some different hematological parameters in a reptilian model 7 naturally exposed to altitude-associated hypoxia. Four populations of the Mexican lizard Sceloporus 8 torquatus (Wiegmann 1828) from different altitudes were sampled to evaluate erythrocyte count 9 (Erc), hematocrit (Hct), mean corpuscular hemoglobin concentration (MCHC) and erythrocyte size 10 (Ers). Blood was also assayed to determine hemoglobin ([Hb]), glucose, lactate and electrolytes 11 concentration. Erc was performed using a Neubauer hemocytometer. Hct was calculated as per cent 12 packed cell volume by centrifuging blood samples. [Hb] was determined using a Bausch and Lomb 13 Spectronic Colorimeter. MCHC was calculated with 100 x [Hb]/Hct. Erythrocyte size (Ers) was 14 calculated from blood smear micro-photographs analyzed with the Sigma Scan Pro software. Serum 15 electrolytes (Na + , K + and Ca 2+ ), pH, glucose, and lactate values from blood samples were obtained 16 through a blood electrolyte analyzer. Highland populations of Sceloporus torquatus exhibited a 17 significant increase in erythrocyte count, hematocrit, erythrocyte size, and hemoglobin 18 concentration. In contrast, MCHC showed no correlation with altitude. Additionally, significant 19differences in lactate, sodium, potassium and calcium were observed in highland populations. In 20 general, we found that most hematological parameters were significantly different among lizard 21 populations from different altitudes. This is the first study to report changes in erythrocyte size in 22 relation to altitude, which could be a physiological response to hypoxia. 23 24