314 research outputs found

    Spelen met verbreding : achtergrondinformatie

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    Hoe kun je multifunctionele landbouw omschrijven : al die activiteiten die plaatsvinden op of vanuit het agrarisch bedrijf die niet primair met voedselproductie te maken hebben, maar die erop gericht zijn anderen te laten delen in de waarden van het landleven én die waarden te gelde te maken. Het gaat dus om bedrijven waarin een substantieel deel van het inkomen wordt gegenereerd uit meer dan productie: de boer wordt zelf leverancier en gebruikt zijn onderneming als een actieve setting en meewerkend décor voor maatschappelijke diensten. Daarbij gaat het om (verschillende vormen van) zorg, recreatie, educatie, productverwerking en huisverkoop, natuurbeheer, en/of de inzet van het totale bedrijf als vitale schakel in samenlevingsprocessen (stadsboerderij)

    Evolutionary Pathways of the Calcitonin (CALC) Genes

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    Recombinant DNA techniques have made it possible to establish the structure of various genes encoding polypeptide hormones. Comparison of nucleotide sequences of the calcitonin (CALC) genes in man has revealed surprising similarities and variations. These findings and the homologies among the sequences in different species offered an opportunity for speculation about relationships between these genes and about their evolutionary origin. The first gene (CALC-I) directing the synthesis of calcitonin (CT) or CT gene-related peptide (CGRP) comprises six exons and gives rise to two mRNAs by an alternative RNA-processing mechanism. The homology between CGRP and CT reflects their common origin. The human genome contains a second gene (CALC-II) that is structurally related to the CALC-I gene. The CALC-II RNA transcripts do not appear to be differentially processed, as only preproCGRP-II mRNA and not preproCT-II is detected. The first and second CTI CGRP genes probably have evolved from a common ancestor gene early in evolution. Meanwhile, a third genomic locus containing nucleotide sequences highly homologous to exons 2 and 3 of both CALC genes was detected and probably generated by duplication of a part of CALC-II. This locus is not likely to encode a CT- or CGRP-related polypeptide hormone. The CALC genes and this last (pseudo) gene are located on the short arm of chromosome 11. Recently, islet or insulinoma-amyloid polypeptide (IAPP) was isolated as a major constituent of amyloid present in human insulinoma and in pancreatic islet amyloid in noninsulin-dependent diabetes mellitus. lAPP shows 46% amino acid sequence homology with human CGRP-II. In contrast to the CALC-genes, the human IAPP gene is located on chromosome 12. All these findings have provided insight into the mechanisms underlying the increasing diversity of polypeptide hormones

    Human serum albumin: twenty-three genetic variants and their population distribution

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66001/1/j.1469-1809.1973.tb00602.x.pd

    MEN-2 Syndrome: The Value of Screening and Central Registration; A Study of Six Kindreds in The Netherlands

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    Since 1975, six families with the MEN-2A syndrome including 66 patients have been identified in The Netherlands. All these patients underwent thyroidectomy for C-cell hyperplasia and/or medullary thyroid carcinoma (MTC); eight were symptomatic (Group A), 51 were relatives of patients found to be affected (Group B), and seven had had a negative screening test that became positive (Group C). To assess the effect of screening, we compared these groups with respect to the occurrence of metastatic MTC at thyroidectomy and the results of the postoperative calcitonin (CT) tests. We found that 87% of Group A, 37% of Group B; and none of Group C had metastatic disease at surgery. The cure rates in these three groups with MEN-2A, as determined by stimulated CT measurement, was 0%, 51%, and 100%, respectively. From these results it may be concluded that screening can lead to the detection of MTC at an earlier stage which in turn could permit curative treatment and improvement of both prognosis and life expectancy. The need for supervision of affected families by central registration to guarantee the continuity of screening is stressed
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