The molecular regulation of exercised-induced muscle fibre hypertrophy in the common carp: expression of MyoD, PCNA and components of the calcineurin-signalling pathway.

Growth was investigated over 16 d in juvenile common carp (Cyprinus carpio L.) held in either static water (tank rested, TR16) or exercised in a flume at 2.5-3.2 body lengths s-1 for 18 h a day (exercised, E16). Relative to the start of the experiment (TR0), the TR16 group showed a 31% increase in body mass (specific growth rate, 1.57% d-1), whereas there was no net change in the E16 group. There was, however, a significant exercise-induced hypertrophy of slow muscle fibres with average fibre cross-sectional area (FCSA) increasing by 35% in the E16 group, compared with 11% in the TR16 group. In contrast, FCSA of fast muscle fibres increased by 34% in the TR16 group compared to just 18% in the E16 group. The relative concentrations and subcellular localisation of proteins hypothesised to play a role in the regulation of muscle growth were measured. MyoD concentration was similar in the TR0, TR16 and E16 groups in both slow and fast muscle. However, there was a small (5%-10%) but statistically significant increase in nuclear localisation of MyoD in those groups showing a significant increase in FCSA over the time course of the experiment. PCNA concentration was 31% and 12% higher in the TR16 than in either the TR0 or E16 groups for slow and fast muscle, respectively. Exercise resulted in a approximately 10% increase in nuclear factor of T-cells (NFAT2) concentration in slow muscle but no change in NFAT2 localisation. Calcineurin B concentration was similar in tank rested and exercised groups. The results do not support a major role for the calcineurin-signalling pathway in the regulation of muscle hypertrophy in the common carp.

The role of myostatin and the calcineurin-signalling pathway in regulating muscle mass in response to exercise training in the rainbow trout Oncorhynchus mykiss Walbaum.

Rainbow trout Oncorhynchus mykiss Walbaum were exercised at 0.8 and 1.6 body lengths s(-1) for 18 h a day over a 30 day period. Exercise resulted in a 24-30% increase in the average cross-sectional area of fast muscle fibres relative to tank-rested controls. The concentrations of growth factors and transcription factors hypothesised to play a role in regulating exercise-induced muscle fibre hypertrophy were measured. Exercise training resulted in a minor increase in calcineurin localisation in the nucleus. However, nuclear factor of T-cells 2 (NFAT2) nuclear localisation did not follow a pattern that was consistent with NFAT2-mediated transcriptional activity and changes in calcineurin signaling. The active peptide of myostatin, a negative regulator of muscle growth in mammals, was downregulated in exercise groups relative to tank-rested controls, but only by 6-7%. It was concluded that myostatin and calcineurin signaling do not play a major role in regulating exercise-induced muscle hypertrophy in trout.

[Obstructive anuria secondary to uterine prolapse]. / Anuria obstructiva secundaria a prolapso uterino.

The prevalence of obstructive uropathy linked to uterine prolapse ranges between 4% and 80%, depending on the series, probably due to the varying degree of severity of the prolapses under consideration. Renal failure or anuria is an unusual complication. Several etiopathogenic theories regarding obstructive uropathy secondary to prolapse have been put forward: ureteral compression by the uterine vessels, severe urethral angulation, ureteral compression against levator ani muscles and the elongation and narrowing of the distal ureter. The major radiological exploration used in studying the urinary tract of these patients is intravenous urography in bipedestation. Emergency treatment for obstructive anuria resulting from a uterine prolapse consists of manually replacement of the prolapse. Surgery is considered to be the definitive ideal treatment, although in the case of surgical or anaesthetic high risk patients, inserting a permanent pessary may constitute a satisfactory solution. We present a case of obstructive anuria resulting from uterine prolapse, which was successfully treated with the insertion of a ring pessary.

Microphotometric quantitation of succinic dehydrogenase in whole isolated osteoclasts.

The microphotometric quantitation of succinic dehydrogenase (SDH) in whole isolated osteoclasts was performed. Osteoclasts were obtained from imprints of the external metaphyseal area of tibia, a zone of physiological bone resorption. SDH was demonstrated histochemically and the reaction product was measured in a Zeiss Cytoscan microphotometer in arbitrary units (AU) of activity from 0 to 500. Total enzyme activity (TEA) was 10 to 50 AU in 78% of the cells. The enzyme concentration (MEC), taken as the activity per unit volume was 0.10 to 0.40 AU in 94% of the cells. Values of reactive cytoplasm area (RCA) were high for most of the cells, but lower for a few, probably mononuclear, osteoclasts. The correlation index for TEA vs RCA was significant. The study of enzyme activity in whole osteoclasts by microphotometric quantitation has been proven possible. This technique could be employed in further studies of enzyme activity of osteoclasts in other physiological or pathological states of bone resorption.