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81.
Gregory Aponte Douglas Gross Grace Rosenquist Verne Mendel Tadataka Yamada 《Peptides》1983,4(6):935-939
Somatostatin, insulin and glucagon concentrations in rat pancreas were measured following various intervals of food-deprivation. Tissue concentrations, as measured by radioimmunoassay, were correlated with A-, B-, and D-cell number and size using a scanning integrating image analyzer (Quantimet 720). Alterations in total islet hormone content were not correlated to changes in size or distribution of cells. This implies that changes in tissue content reflect changes in turnover of peptides rather than changes in cell size or number. 相似文献
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W H Douglas E S Reeh N Ramasubbu P A Raj K K Bhandary M J Levine 《Biochemical and biophysical research communications》1991,180(1):91-97
The lubricating properties of human submandibular-sublingual salivary fractions were examined using a servohydraulic model of mandibular movement. Fractions containing statherin exhibited a strong tendency to boundary lubrication. The lubricity of purified statherin was confirmed and compared to the amphipathic molecules gramacidin S and sodium dodecyl sulfate. Contact angle measurements of statherin paralleled the other amphipathic molecules. The helical content of statherin increased in trifluoroethanol indicating the presence of amphipathic helical regions. CD studies and hydrophobic moment calculations indicated that statherin adopts an amphipathic helical conformation at the N-terminus. An energy-minimized model of the polar N-terminal residues 1-15 suggested that this domain could be positioned in space to interact with a hydroxyapatite substrate. These data imply that under appropriate conditions statherin may display an amphipathic nature which enables it to function as a boundary lubricant on enamel. 相似文献
85.
Douglas G Altman 《BMJ (Clinical research ed.)》1991,303(6799):416-417
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Summary Complete hydatidiform moles contain only paternal chromosomes. To learn more of their origin, we used restriction endonuclease site polymorphisms found in the parental mitochondrial DNAs to demonstrate that moles contain exclusively maternal mitochondrial DNA. Thus, moles must arise from the fusion of one or two sperm with a mature but anucleate ovum. 相似文献
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J R Douglas C A Campbell D M Salisbury J A Walker-Smith C B Williams 《BMJ (Clinical research ed.)》1980,281(6252):1386-1387
Five children presenting with chronic and intermittent rectal bleeding were diagnosed as having colorectal polyps by fibreoptic colonoscopy performed under sedation. Three of the children had had barium-enema films reported on as normal. Eight polyps were seen, of which six were proximal to the sigmoid colon. All were removed endoscopically (one by proctoscopy, one by snare-intussusception) without complication. Colonoscopic polypectomy is a safe and efficient procedure in children, and colonoscopy may be regarded as first-line management in those with rectal bleeding. 相似文献
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