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In previous studies, glucagon receptor knockout mice (Gcgr(-/-)) display reduced blood glucose and increased glucose tolerance, with hyperglucagonemia and increased levels of glucagon-like peptide (GLP)-1. However, the role of glucagon receptor signaling for the regulation of islet function and insulin sensitivity is unknown. We therefore explored beta-cell function and insulin sensitivity in Gcgr(-/-) and wild-type mice. The steady-state glucose infusion rate during hyperinsulinemic-euglycemic clamp was elevated in Gcgr(-/-) mice, indicating enhanced insulin sensitivity. Furthermore, the acute insulin response (AIR) to intravenous glucose was higher in Gcgr(-/-) mice. The augmented AIR to glucose was blunted by the GLP-1 receptor antagonist, exendin-3. In contrast, AIR to intravenous administration of other secretagogues was either not affected (carbachol) or significantly reduced (arginine, cholecystokinin octapeptide) in Gcgr(-/-) mice. In islets isolated from Gcgr(-/-) mice, the insulin responses to glucose and several insulin secretagogues were all significantly blunted compared with wild-type mice. Furthermore, glucose oxidation was reduced in islets from Gcgr(-/-) mice. In conclusion, the present study shows that glucagon signaling is required for normal beta-cell function and that insulin action is improved when disrupting the signal. In vivo, augmented GLP-1 levels compensate for the impaired beta-cell function in Gcgr(-/-) mice. [ABSTRACT FROM AUTHOR]

Morita E, Narikiyo M, Nishimura E, Yano A, Tanabe C, Sasaki H, Hanada N. Molecular analysis of age-related changes ofStreptococcus anginosusgroup andStreptococcus mitisin saliva.Oral Microbiol Immunol 2004: 19: 386–389.© Blackwell Munksgaard, 2004.The purpose of this study was to survey the prevalence of streptococcal species, especiallyStreptococcus anginosus(which has been reported to be associated with cancer in the upper digestive tract),Streptococcus constellatus, andStreptococcus intermediusin the saliva of different age groups. A sequence analysis of 16S rDNA was performed and DNA quantified using real-time polymerase chain reaction. TheS. anginosuslevel increased with age, whereas the levels ofS. constellatusandS. intermediusdid not change.Streptococcus mitiswas the predominant species in the saliva of all the age groups but, unlike theS. anginosus, the proportion ofS. mitisin the salivary bacteria decreased with age. The increase inS. anginosuswith age should be carefully monitored because of its association with diseases, including cancer. [ABSTRACT FROM AUTHOR]

ITO films were deposited by d.c. magnetron sputtering with/without H2O introduction. The structural and optoelectrical properties of the films were analyzed in detail. The films deposited with H2O introduction exhibited an entirely amorphous structure, whereas the as-deposited films deposited without H2O introduction exhibited a polycrystalline In2O3 structure. The amorphous ITO films deposited under the high H2O partial pressure were confirmed to contain a much higher concentration of hydrogen inside the films by secondary ion mass spectroscopy, which remained after post-annealing at 350 °C. The crystallization temperature of the films subjected to post-annealing was increased to higher than 220 °C. These stable amorphous ITO films had a wet-etching rate in oxalic acid solution two orders of magnitude higher than that of the films deposited without H2O introduction. [Copyright &y& Elsevier]

Rhodamine-123 (Rh-123) has been tested recently as a new laser dye for photodynamic therapy of human tumors in vitro and in vivo. Prior to initiation of clinical studies of this technique, we evaluated the biodistribution, metabolism, and pathological changes of Rh-123 in rabbits after systemic, repetitive injections of the dye in escalating doses. At doses between 0.1 to 1 mg/kg of Rh-123 injected intramuscularly (IM) daily for 5 days, no local or systemic toxicity was observed during the 4 weeks of follow-up. The peak concentrations of Rh-123 in micrograms/g of tissue was distributed as follows: kidney (3.24) greater than heart (2.24) greater than spleen (1.77) greater than lung (0.61) greater than liver (0.38) greater than skin (0.30) greater than skeletal muscle (0.17) greater than genitals (0.13) greater than brain (0.04). The elimination of Rh-123 was very rapid, with the dye falling to 2.7% of peak concentration at 72 hours in the kidneys, and to undetectable levels at 240 hours postinjection in all organs, except the skin, which retained 3% of the peak level at 240 hours. The low toxicity and rapid metabolism of Rh-123 in this preclinical model suggests that the dye and Argon laser may represent an effective combination for treatment of superficial malignancies. [ABSTRACT FROM AUTHOR]