Role of counterregulatory hormones for glucose metabolism in children and adolescents with type 1 diabetes.

To elucidate the mechanism of insulin resistance due to insulin counterregulatory hormones (ICRHs) and evaluate ICRH secretion kinetics, ICRH concentrations were measured and correlated with blood glucose levels in 28 type 1 diabetic patients. Blood glucose was measured before bedtime. Early morning urine samples were collected the next morning before insulin injection and breakfast. Fasting blood glucose, cortisol, glucagon and HbA1c levels were measured. Growth hormone (GH), adrenaline, cortisol and C-peptide levels in morning urine samples were measured; SD scores were calculated for urine GH. The laboratory values (mean ± SD) were as follows; HbA1c of 8.1% ± 1.4%; pre-bedtime glucose of 203 ± 105 mg/dl; fasting blood glucose of 145 ± 87 mg/dl; serum cortisol of 21.6 ± 5.5 µg/dl; plasma glucagon of 98 ± 41 pg/ml; urinary GH, 27.2 ± 13.0 ng/gCr; urinary cortisol of 238 ± 197 ng/gCr; and urinary Adrenaline of 22.9 ± 21.0 ng/gCr. The mean urinary GH SD score was increased (+1.01 ± 0.70; p=0.000); the mean plasma glucagon lebel (98 ± 41 pg/ml) was not. Fasting blood glucose was positively correlated with plasma glucagon (R=0.378, p=0.0471) and negatively correlated with urinary cortisol (R=-0.476, p=0.010). Urinary adrenaline correlated positively with urinary GH (R=0.470, p=0.013) and urinary cortisol (R=0.522, p=0.004). In type 1 diabetes, GH, glucagon and cortisol hypersecretion may contribute to insulin resistance, but the mechanism remains unclear.

Physical performance evaluation of a 256-slice CT-scanner for four-dimensional imaging.

We have developed a prototype 256-slice CT-scanner for four-dimensional (4D) imaging that employs continuous rotations of a cone-beam. Since a cone-beam scan along a circular orbit does not collect a complete set of data to make an exact reconstruction of a volume [three-dimensional (3D) image], it might cause disadvantages or artifacts. To examine effects of the cone-beam data collection on image quality, we have evaluated physical performance of the prototype 256-slice CT-scanner with 0.5 mm slices and compared it to that of a 16-slice CT-scanner with 0.75 mm slices. As a result, we found that image noise, uniformity, and high contrast detectability were independent of z coordinate. A Feldkamp artifact was observed in distortion measurements. Full width at half maximum (FWHM) of slice sensitivity profiles (SSP) increased with z coordinate though it seemed to be caused by other reasons than incompleteness of data. With regard to low contrast detectability, smaller objects were detected more clearly at the midplane (z = 0 mm) than at z = 40 mm, though circular-band like artifacts affected detection. The comparison between the 16-slice and the 256-slice scanners showed better performance for the 16-slice scanner regarding the SSP, low contrast detectability, and distortion. The inferiorities of the 256-slice scanner in other than distortion measurement (Feldkamp artifact) seemed to be partly caused by the prototype nature of the scanner and should be improved in the future scanner. The image noise, uniformity, and high contrast detectability were almost identical for both CTs. The 256-slice scanner was superior to the 16-slice scanner regarding the PSF, though it was caused by the smaller transverse beam width of the 256-slice scanner. In order to compare both scanners comprehensively in terms of exposure dose, noise, slice thickness, and transverse spatial resolution, K=Dsigma2ha3 was calculated, where D was exposure dose (CT dose index), sigma was magnitude of noise, h was slice thickness (FWHM of SSP), and a was transverse spatial resolution (FWHM of PSF). The results showed that the K value was 25% larger for the 16-slice scanner, and that the 256-slice scanner was 1.25 times more effective than the 16-slice scanner at the midplane. The superiority in K value for the 256-slice scanner might be partly caused by decrease of wasted exposure with a wide-angle cone-beam scan. In spite of the several problems of the 256-slice scanner, it took a volume data approximately 1.0 mm (transverse) x 1.3 mm (longitudinal) resolution for a wide field of view (approximately 100 mm long) along the zeta axis in a 1 s scan if resolution was defined by the FWHM of the PSF or the SSP, which should be very useful to take dynamic 3D (4D) images of moving organs.

Effects of growth hormone on testicular dysfunction induced by cyclophosphamide (CP) in GH-deficient rats.

Growth hormone (GH) is known to accelerate spermatogenesis and maintain gonadal function. In this study, we evaluated the effect of GH on recovery from testicular damage induced by cyclophosphamide (CP). Eleven- to fourteen-week-old GH-deficient Lewis rats (dw/dw) were divided into 4 groups (n = 10 each), with one group serving as controls. In the CP group, CP was intravenously administered in daily doses of 50 mg/kg for 2 days, followed by daily doses of 10 mg/kg for the next 3 days. In the GH group, rat GH was subcutaneously administered at a daily dose of 0.3 mg/kg until the rats were sacrificed. In the CP/GH group, GH and CP administration were started simultaneously. In the CP/preGH group, GH administration was started 14 days before CP administration. Five rats from each group were sacrificed at days 14 and 28 after administration of CP. Spermatogenesis was then evaluated morphometrically by counting numbers of cells at several stages of the spermatogenic cycle. On day 14, there were no significant differences in the numbers of the spermatocytes between CP and CP/GH group. On day 28, the numbers of spermatocytes and motility of spermatozoa in CP/GH group were greater than those of CP group were. In the CP/preGH group, these effects of GH administration were not observed. These results suggested that administration of GH improved testicular function damaged by CP under GH-deficient condition, when GH and CP administration are started simultaneously.