No abstract

To evaluate the role of serum free or unbound insulin-like growth factor I (IGF-I) on bone growth, we measured serum free IGF-I levels in 354 healthy children and adults (193 males and 161 females, aged 0-40 yr) and in 21 prepubertal GH-deficient (GHD) children (complete GHD, n = 5; partial GHD, n = 16) using a recently developed immunoradiometric assay. We obtained the following results. 1) In the normal children, the serum free IGF-I levels were low in infancy (<1 yr of age; males, 0.71 +/- 0.26 microg/L, mean +/- SD; females, 1.05 +/- 0.49 microg/L), increased during puberty (males, 5.84 +/- 2.18 microg/L; females, 5.80 +/- 1.49 microg/L), and declined thereafter. 2) Free IGF-I in the serum occupied about 0.95-2.02% of the total IGF-I values, with the highest ratio occurring in infancy (males, 1.77 +/- 0.60%; females, 2.02 +/- 0.87%). 3) The SD scores of serum free IGF-I in the 21 GHD children ranged from -3.30 to 0.30, and the 5 complete GHD children had free IGF-I values more than -2 SD below those of age-matched normal subjects. 4) There was a significant correlation between the SD scores of free IGF-I and those of total IGF-I (r = 0.715; P < 0.0005) in the GHD children. 5) In the 16 partial GHD children receiving GH treatment, the serum free IGF-I levels were elevated to 209% of pretreatment levels after 1 month of GH treatment and remained high during GH therapy. The GH-induced increase in the serum free IGF-I levels was significantly higher than those of the total IGF-I and IGF binding protein-3 levels. 6) The percent increase in the serum free IGF-I level after 1 month of GH treatment showed a significant positive correlation with that of the GH-induced improvement in the percent increase in the height velocity during 1 yr of GH therapy (r = 0.526; P < 0.05). These results show that free IGF-I in the serum has an essential role in bone formation because the higher free IGF-I levels were observed when the growth rate accelerated. The measurement of serum free IGF-I may become a useful tool for both diagnosing GH deficiency and predicting growth responses to long term GH therapy.

No abstract

The applicability of terahertz (THz) waves to the detection of rust in coated steel plates has been examined. Spectral intensity measurements of reflected light from a sample coated with epoxy resin show that optical coherence tomography using near-infrared light and THz waves can detect the hidden rest region. This region can be reproduced by so-called THz imaging without contact. Since rust exhibits strong absorption in the frequency range from 1 to 5 THz, the absorption coefficient can be used to estimate the rust state with high sensitivity. In contrast, neither X-ray fluorescence nor Fourier transform infrared spectroscopy can detect the rust, because of the strong X-ray and IR peaks of the coating. Electro-chemical impedance measurement, which is one of the promising diagnostic methods, judges the water blocking ability of the coating. The impedance value and THz absorption due to rust shows good correlation until the amount of water in the film reaches its maximum.