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91.
The conversion of proparathyroid hormone to parathyroid hormone (PTH) was studied in vitro employing pancreatic trypsin as a prototype converting enzyme. Digestion of intact radiolabeled bovine prohormone with trypsin (0.1%) (w/w) resulted in release of a peptide comigrating with intact hormone marker in systems resolving both on the basis of charge (urea polyacrylamide gels, pH 4.4) and size (sodium dodecyl sulfate-urea polyacrylamide gels, pH 7.2). Tryptic digestions of a synthetic analogue of bovine prohormone, ProPTH-(-6 + 34), consisting of the prohormone hexapeptide covalently bonded to the NIH2 terminus of the active fragment of the hormone, released in high yield the hexapeptide and the intact active hormone fragment before any other smaller fragments. Analyses of digestions were by: (i) thin-layer chromatography and amino acid analysis of digestion products; (ii) comparison of the biological activity of the prophormone substrate and the products of digestion; and (iii) peptide end-group analysis by the Edman method during progressive tryptic hydrolysis over 22 h. The latter experiments demonstrated cleavage of more than 75% of the hexapeptide-hormone peptide bond before cleavage of other trypsin-sensitive sites within the molecule. It is concluded that the specificity of cleavage at the hexapeptide-hormone bond in the process of intracellular hydrolysis of proparathyroid hormone resides primarily in the sequence and/or conformation of the precursor molecule; inasmuch as conversion of prohormone to hormone can be efficiently accomplished by pancreatic trypsin in vitro, there is, therefore, no need to postulate the existence of an intracellular converting enzyme within the parathyroid cell that possesses unique hydrolytic specificity. 相似文献
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AB Houston NL Gregory A Shaw DJ Wheatley EN Coleman 《Canadian Metallurgical Quarterly》1977,39(10):1071-1075
A wide angle (60 degrees) sector scanner producing a real-time two-dimensional echocardiogram has been used to examine healthy infants, children, and adults. Its method of use is described and findings from longitudinal and transverse scans are presented. The points of difference between the various types of electronic and mechanical two-dimensional scanning systems are discussed. This equipment minimises problems of chest contact and rib and lung interference and, by providing echocardiograms of high line density from a wide angle, is a suitable real-time two-dimensional scanning system for examining patients of all ages. 相似文献
95.
Children with cleft lip and palate require interdisciplinary team care from infancy through adolescence. An understanding of developmental stages allows the cleft palate team to adapt and integrate its services into the rapidly changing life of the child. This article discusses the maturational, developmental stages of childhood and the services the child with cleft lip and palate and the child's family deserve through each stage. Health care providers in all settings may continue to provide appropriate care for all patients with cleft lip and palate, despite the challenges of a changing health care environment, by emphasizing the needs of the child in all developmental stages. 相似文献
96.
The paper reports 7 cases of dimorphic anemia, development of Addison-Biermer disease in preexisting chronic posthemorrhagic anemia. The authors consider some diagnostic and therapeutic aspects. It is thought valid to discontinue iron preparations prior to vitamin B12 therapy and to start them again upon the arising reticulocytic crisis. 相似文献
97.
The cagA gene was detected in 100% of 16 Helicobacter pylori isolates from patients with gastric carcinoma versus 78% of 18 isolates from patients with duodenal ulcers (P = 0.344) and only 64% of 22 isolates from patients with gastritis only (P = 0.005) in Brazil. Also, there was a significant association between isolation of cagA+ s1-type vacA H. pylori in cases of stomach cancer and ulcers as opposed to cases of gastritis only (P = 0.004), but this was not true in Houston (P = 0.238), where 94% of all isolates were cagA+. 相似文献
98.
AE Gharavi EN Harris LR Sammaritano SS Pierangeli J Wen 《Canadian Metallurgical Quarterly》1993,122(4):426-431
High positive anticardiolipin antibody tests have been associated with recurrent thrombosis and pregnancy loss. Although these antibodies were believed to bind negatively charged phospholipids, recent reports have suggested that a serum protein, beta 2-glycoprotein I (beta 2-GPI), may be the true antigen for these antibodies. To resolve this issue, we compared binding of 75 anticardiolipin-positive and 71 anticardiolipin-negative serum samples from patients with rheumatic diseases to beta 2-GPI by using an enzyme-linked immunosorbent assay (ELISA). Serum samples from 30 healthy blood donors and 10 laboratory personnel were used as normal controls. We found no difference in binding between the three groups of serum samples. In addition, when binding to beta 2-GPI coated plates was compared with binding to ELISA plates without beta 2-GPI (blank), no difference was observed. Finally, binding of anticardiolipin-positive serum samples to plates coated with cardiolipin-beta 2-GPI mixture varied directly with the cardiolipin concentrations. Based on these findings, we conclude that anticardiolipin-positive serum samples do not bind beta 2-GPI. 相似文献
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MK Chekhranova ER Shuvalova EN Ilína DIu Pankov SB Diabirova IuA Pankov 《Canadian Metallurgical Quarterly》1994,(12):17-19
A human insulinoma cDNA library was constructed in the expression plasmid vector pUEX1. The clone pUEX1Ins12 was selected by means of hybridization with an insulin probe. It codes for full size amino acid sequence preproinsulin. The bacterial strain pUEX3Ins8 producing proinsulin as beta-galactosidase fusion protein was obtained for the use of recombinant protein as an antigen in an ELISA to detect serum antibodies in subjects with IDDM. Recombinant clones containing the middle, N- and C-terminal domains of the GAD65, the major autoantigen in IDDM, were constructed in pVEX1. These clones may become important tools to study the nature of GAD autoreactivity in IDDM. The clone pHICEO.9 was selected from the human insulinoma cDNA library by immunoscreening with total human insulinoma protein antibodies. This clone expresses the C-terminal fragment of human cholesterol esterase/lipase containing its antigenic determinant and can be used for blood lipase determination. Four clones containing cDNA inserts (0.47-1.42 kb) without any significant homologies to the known sequences in the Gene Bank were obtained by means of statistic selection. 相似文献