Somatostatin Agonist Pasireotide Inhibits Exercise-Stimulated Growth in the Male Siberian Hamster (Phodopus sungorus).

The Siberian hamster (Phodopus sungorus) is a seasonal mammal, exhibiting a suite of physiologically and behaviourally distinct traits dependent on the time of year and governed by changes in perceived day length (photoperiod). These attributes include significant weight loss, reduced food intake, gonadal atrophy and pelage change with short-day photoperiod as in winter. The central mechanisms driving seasonal phenotype change during winter are mediated by a reduced availability of hypothalamic triiodothyronine (T3), although the downstream mechanisms responsible for physiological and behavioural changes are yet to be fully clarified. With access to a running wheel (RW) in short photoperiod, Siberian hamsters that have undergone photoperiod-mediated weight loss over-ride photoperiod-drive for reduced body weight and regain weight similar to a hamster held in long days. These changes occur despite retaining the majority of hypothalamic gene expression profiles appropriate for short-day hamsters. Utilising the somatostatin agonist pasireotide, we recently provided evidence for an involvement of the growth hormone (GH) axis in the seasonal regulation of bodyweight. In the present study, we employed pasireotide to test for the possible involvement of the GH axis in RW-induced body weight regulation. Pasireotide successfully inhibited exercise-stimulated growth in short-day hamsters and this was accompanied by altered hypothalamic gene expression of key GH axis components. Our data provide support for an involvement of the GH axis in the RW response in Siberian hamsters.

Somatostatin Agonist Pasireotide Promotes a Physiological State Resembling Short-Day Acclimation in the Photoperiodic Male Siberian Hamster (Phodopus sungorus).

The timing of growth in seasonal mammals is inextricably linked to food availability. This is exemplified in the Siberian hamster (Phodopus sungorus), which uses the annual cycle of photoperiod to optimally programme energy expenditure in anticipation of seasonal fluctuations in food resources. During the autumn, energy expenditure is progressively minimised by physiological adaptations, including a 30% reduction in body mass, comprising a reduction in both fat and lean tissues. However, the mechanistic basis of this adaptation is still unexplained. We hypothesised that growth hormone (GH) was a likely candidate to underpin these reversible changes in body mass. Administration of pasireotide, a long-acting somatostatin receptor agonist developed for the treatment of acromegaly, to male hamsters under a long-day (LD) photoperiod produced a body weight loss. This comprised a reduction in lean and fat mass, including kidneys, testes and brown adipose tissue, typically found in short-day (SD) housed hamsters. Furthermore, when administered to hamsters switched from SD to LD, pasireotide retarded the body weight increase compared to vehicle-treated hamsters. Pasireotide did not alter photoperiod-mediated changes in hypothalamic energy balance gene expression but altered the expression of Srif mRNA expression in the periventricular nucleus and Ghrh mRNA expression in the arcuate nucleus consistent with a reduction in GH feedback and concurrent with reduced serum insulin-like growth factor-1. Conversely, GH treatment of SD hamsters increased body mass, which included increased mass of liver and kidneys. Together, these data indicate a role for the GH axis in the determination of seasonal body mass of the Siberian hamster.

[Morphometric dual-energy roentgen absorptiometry in follow-up of scoliosis]. / Morphometrische Zwei-Energie-Röntgenabsorptiometrie zur Verlaufsbeurteilung von Skoliosen.

PURPOSE: Taking pictures of the spine with Morphometric X-ray Absorptiometry (DXA) leads to a radiation dose of just 1% of conventional X-ray. Purpose of this study was to evaluate if DXA is a suitable method for sufficient measuring of the scoliosis angle. METHOD: We examined 20 patients with scolioses I. Control-pictures were made with conventional X-rays and compared to those made by DXA, measuring of scoliosis angle was performed by the method of Lippmann/Cobb. RESULTS: The difference between both methods was -10.5% DXA to conventional X-ray-each angle examined on DXA was smaller. CONCLUSION: It is possible to measure scolioses I on DXA.

Determination of skeletal maturity by ultrasound: a preliminary report.

OBJECTIVE: Replacement of radiography by sonography for determination of skeletal maturity. DESIGN: Sonographic and radiographic evaluation of the maturation of the iliac bone apophysis (Risser's sign) and evaluation of the distal radial epiphyses. PATIENTS: 64 children and adolescents with idiopathic scoliosis, aged from 5 to 19 years. RESULTS: Sonograms with corresponding radiographs were available for the hand and wrist in 36 cases and for the iliac bone in 28 cases. Comparison of sonographic with radiological data revealed sonography to have a sensitivity for qualifying the status of the distal radial epiphysis of 93.1%. Specificity was 100%, accuracy 94.4% for investigation of the distal radial epiphysis. Overall accuracy for correct determination of Risser's stage by ultrasound (in comparison with the radiographic standard) was 89.2%. CONCLUSIONS: These findings suggest that ultrasound is a useful and highly acceptable tool for bone age determination in clinical routine or screening studies and will help to reduce ionizing radiation to children and adolescents.