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101.
K Yamada X Yuan S Ishiyama K Koyama F Ichikawa A Koyanagi W Koyama K Nonaka 《Canadian Metallurgical Quarterly》1997,40(6):706-710
In insulin-dependent diabetes mellitus (IDDM), inappropriate growth hormone (GH) responses to several stimuli, including GH-releasing hormone (GHRH), have been described. A decreased hypothalamic somatostatinergic tone is one of the most likely explanations for these findings. His-DTrp-Ala-Trp-DPhe-Lys-NH2 [GH-releasing peptide-6 [GHRP-6]] is a synthetic hexapeptide that stimulates GH release in vitro and in vivo. The mechanism of action of GHRP-6 is unknown, but it probably does not inhibit hypothalamic somatostatin secretion. Also, GHRH and GHRP-6 apparently activate different intracellular pathways to release GH. The aim of this study was to evaluate whether there is a differential effect of IDDM on GHRP-6- and GHRH-induced GH secretion. Six patients with IDDM and seven control subjects were studied. Each subject received GHRP-6 (1 microgram/kg intravenously [IV]), GHRH (100 micrograms IV), and GHRP-6 + GHRH on 3 separate days. GH peak values (mean +/- SE in micrograms per liter) were similar in controls and diabetics after GHRH (22.5 +/- 7.8 v 24.0 +/- 9.7) and after GHRP-5 (20.5 +/- 5.3 v 24.4 +/- 6.3). The association of GHRP-6 and GHRH induced a significantly higher GH release than administration of the isolated peptides in both groups. The synergistic GH response to combined administration of GHRP-6 and GHRH was not different in controls (70.5 +/- 20.0) and diabetics (119.0 +/- 22.2). In summary, the effectiveness of GHRP-6 in IDDM could reinforce the evidence that this peptide probably does not release GH through a decrease in hypothalamic somatostatin secretion. Moreover, our data suggest that both GHRH and GHRP-6 releasing mechanisms are unaltered in IDDM. 相似文献
102.
T Ikeya M Tsuda H Hara S Koyama S Sugiyama T Misaki 《Canadian Metallurgical Quarterly》1997,50(12):1055-1058
62-year-old woman admitted our hospital with pain of left upper extremity from the left chest and dysphasia. Chest X-ray showed the huge mass shadow in the left lung field. Diabetes mellitus and inflammatory reaction such as high fervor, leukocytosis, CRP and ESR accentuation were recognized. Conservative therapy was done at first, but mass shadow on X-ray increased, and swelling appeared from the neck to the left lateral chest wall. And the same site appeared like subcutaneous emphysema. Computed Tomography showed mass shadow which was enlarged and spread in lung parenchyma and left chest wall with bubble image. Incision and open drainage was performed for the left chest wall but origin bacteria was detected in neither anaerobic nor aerobic culture of pus. Inflammation and mass shadow of left upper lung field have decreased gradually. The patient discharged without bronchoalveolar fistula. Abscess extending from the neck or chest wall with diabetes mellitus is very rare. 相似文献
103.
A simple formula of the dynamic spectral width of a directly modulated dynamic-single-mode (DSM) laser, and the related maximum transmission bandwidth of a single-mode fiber limited by chromatic dispersion are theoretically given. The dynamic spectral width of a DSM laser is determined by the modulated optical shape and the linewidth enhancement factor α. The spectral width caused by the dynamic wavelength shift is shown to be larger by (1 + alpha^{2} )1/2than that caused by the sideband of the signal of the intensity modulation. Furthermore, the maximum transmission bandwidth of a conventional single-mode fiber with a DSM laser is expressed by using the parameter α and the chromatic dispersion of the fiber. The product of the maximum bit rate and the square root of the fiber length at the wavelength of 1.55 μm is estimated to be about 25 Gbit/s . km1/2. 相似文献
104.
105.
E Koyama JL Leatherman A Shimazu HD Nah M Pacifici 《Canadian Metallurgical Quarterly》1995,203(2):152-162
Since the European frogs (Rana spp.) have fallen under the German endangered species regulation, Xenopus laevis (South African Clawed Frog) is being used increasingly in animal research and education. Optimal growth rates and homogeneity of groups have not necessarily been attained as little statistical analysis of growth data has been available. Following metamorphosis, an as yet not understood variability of growth is exhibited by X. laevis. In this study the effect of environmental factors on this variability was determined. Feeding, population density, background colouring, water temperature, the availability of hiding places, water level and water care were each examined separately. Development of body weight and body length were recorded. A definite correlation between the feeding programme, population density, cover and water care on the one hand and growth on the other were seen. Of lesser importance were water temperature, water level and background colouring. The observed variability of growth is assumed to also be of ethological origin. 相似文献
106.
Y. Onishi N. Nishiyama C. Caneau F. Koyama Chung-en Zah 《Photonics Technology Letters, IEEE》2004,16(5):1236-1238
An all-optical inverter using transverse-mode switching of a 1.55-/spl mu/m vertical-cavity surface-emitting laser is demonstrated. When an external light is injected to a first high-order mode, the output power of the fundamental mode is strongly suppressed due to injection locking resulting in a large extinction ratio of over 20 dB. Waveform inversion is demonstrated for the input signal of a 5-GHz sinusoidal wave. 相似文献
107.
1.53 ?m GaInAsP/InP buried-heterostructure integrated twin-guide laser with distributed Bragg reflector (BH-DBR-ITG laser) was directly modulated with microwave modulation current superimposed on a DC bias which was fixed at 1.1 times the threshold current, and single-wavelength operation was experimentally confirmed with a modulation frequency up to 1 GHz and a modulation depth of 100%. 相似文献
108.
Experimental results are presented for fundamental logic performances in a planner Gunn-effect device with two separated cathodes, which was fabricated on an epitaxial GaAs grown on a semi-insulating substrate. By selecting the polarity of input trigger pulses with respect to that of the biasing voltage, two functions, exclusive-OR (comparator) and inclusive-OR can be realised, as found by our computer simulation. 相似文献
109.
110.
A Irie S Koyama Y Kozutsumi T Kawasaki A Suzuki 《Canadian Metallurgical Quarterly》1998,273(25):15866-15871
N-Glycolylneuraminic acid (NeuGc) is abundantly expressed in most mammals, but it is not detectable in humans. The expression of NeuGc is controlled by cytidine monophospho-N-acetylneuraminic acid (CMP-NeuAc) hydroxylase activity. We previously cloned a cDNA for mouse CMP-NeuAc hydroxylase and found that the human genome contains a homologue. We report here the molecular basis for the absence of NeuGc in humans. We cloned a cDNA for human CMP-NeuAc hydroxylase from a HeLa cell cDNA library. The cDNA encodes a 486-amino acid protein, and its deduced amino acid sequence lacks a domain corresponding to the N-terminal 104 amino acids of the mouse CMP-NeuAc hydroxylase protein, although the human protein is highly identical (93%) to the rest of the mouse hydroxylase protein. The N-terminal truncation of the human hydroxylase is caused by deletion of a 92-base pair-long exon in human genomic DNA. The human hydroxylase expressed in COS-7 cells exhibited no enzymatic activity, and a mouse hydroxylase mutant, which lacks the N-terminal domain, was also inactive. A chimera composed of the human hydroxylase and the N-terminal domain of the mouse hydroxylase displayed the enzyme activity. These results indicate that the human homologue of CMP-NeuAc hydroxylase is inactive because it lacks an N-terminal domain that is essential for enzyme activity. The absence of NeuGc in human glycoconjugates is due to a partial deletion in the gene that encodes CMP-NeuAc hydroxylase. 相似文献