5 research outputs found
Smaller radiate Nummulites of Northwestern Europe
After the completion of J. P. H. KAASSCHIETER's monograph on the "Eocene
Foraminifera of Belgium" (1961), an extensive collection of smaller radiate
Nummulites from the Belgian Eocene remained without specific determination
in the collections of the Utrecht Geological Institute. KAASSCHIETERhad found
that naming these fossils on the basis of the existing literature would lead to
very unsatisfactory results. He felt that a tremendous lot of work in measuring
and counting should be needed to arrive at a still dubious ultimate result, for
which reason he preferred to leave his collections as an heritage to a later
generation.
Since a rapid survey of the material shows no clear pattern of development
within this group of Nummulites, no single student dared undertake the work.
It was not until early 1963, while A. PAPP stayed in Utrecht for three months,
that he and P. MARKSdeveloped a working scheme and put everybody available,
some fifteen people altogether, to worL.
At the end of these three months the results confirmed the previous opinion
that the Eocene and Early Oligocene smaller Nummulites of the North Sea
basin showed a peculiar evolutionary pattern and that they were of dubious
stratigraphic value. Because of these rather disappointing conclusions the work
slowed down, although at various time intervals additional data were gathered.
Eventually, however, the evolution pattern and the stratigraphic results were
considered to be certainly worth publishing in the context of renewed interest
and activities around the Nordic Paleogene
Comprehensive Mutation Analysis of PMS2 in a Large Cohort of Probands Suspected of Lynch Syndrome or Constitutional Mismatch Repair Deficiency Syndrome
Monoallelic PMS2 germline mutations cause 5%-15% of Lynch syndrome, a midlife cancer predisposition, whereas biallelic PMS2 mutations cause approximately 60% of constitutional mismatch repair deficiency (CMMRD), a rare childhood cancer syndrome. Recently improved DNA- and RNA-based strategies are applied to overcome problematic PMS2 mutation analysis due to the presence of pseudogenes and frequent gene conversion events. Here, we determined PMS2 mutation detection yield and mutation spectrum in a nationwide cohort of 396 probands. Furthermore, we studied concordance between tumor IHC/MSI (immunohistochemistry/microsatellite instability) profile and mutation carrier state. Overall, we found 52 different pathogenic PMS2 variants explaining 121 Lynch syndrome and nine CMMRD patients. In vitro mismatch repair assays suggested pathogenicity for three missense variants. Ninety-one PMS2 mutation carriers (70%) showed isolated loss of PMS2 in their tumors, for 31 (24%) no or inconclusive IHC was available, and eight carriers (6%) showed discordant IHC (presence of PMS2 or loss of both MLH1 and PMS2). Ten cases with isolated PMS2 loss (10%; 10/97) harbored MLH1 mutations. We confirmed that recently improved mutation analysis provides a high yield of PMS2 mutations in patients with isolated loss of PMS2 expression. Application of universal tumor prescreening methods will however miss some PMS2 germline mutation carriers
A Genome-Wide Association Study of IVGTT-Based Measures of First Phase Insulin Secretion Refines the Underlying Physiology of Type 2 Diabetes Variants.
Published onlineJournal ArticleThis is the author accepted manuscript. The final version is available from American Diabetes Association via the DOI in this record.Understanding the physiological mechanisms by which common variants predispose to type 2 diabetes requires large studies with detailed measures of insulin secretion and sensitivity. Here we performed the largest genome-wide association study of first phase insulin secretion, as measured by intravenous glucose tolerance tests, using up to 5,567 non-diabetic individuals from 10 studies. We aimed to refine the mechanisms of 178 known associations between common variants and glycaemic traits and identify new loci. Thirty type 2 diabetes, or fasting glucose raising, alleles were associated with a measure of first phase insulin secretion at P<0.05, and provided new evidence, or the strongest evidence yet, that insulin secretion, intrinsic to the islet cells, is a key mechanism underlying the associations at the HNF1A, IGFBP2, KCNQ1, HNF1B, VPS13C/C2CD4A, FAF1, PTPRD, AP3S2, KCNK16, MAEA, LPP, WFS1 and TMPRSS6 loci. The fasting glucose raising allele near PDX1, a known key insulin transcription factor, was strongly associated with lower first phase insulin secretion but has no evidence for an effect on type 2 diabetes risk. The diabetes risk allele at TCF7L2 was associated with a stronger effect on peak insulin response than on C-peptide-based insulin secretion rate, suggesting a possible additional role in hepatic insulin clearance or insulin processing. In summary, our study provides further insight into the mechanisms by which common genetic variation influences type 2 diabetes risk and glycaemic traits
Essential role of MCM proteins in premeiotic DNA replication.
A critical event in eukaryotic DNA replication involves association of minichromosome maintenance (MCM2-7) proteins with origins, to form prereplicative complexes (pre-RCs) that are competent for initiation. The ability of mutants defective in MCM2-7 function to complete meiosis had suggested that pre-RC components could be irrelevant to premeiotic S phase. We show here that MCM2-7 proteins bind to chromatin in fission yeast cells preparing for meiosis and during premeiotic S phase in a manner suggesting they in fact are required for DNA replication in the meiotic cycle. This is confirmed by analysis of a degron mcm4 mutant, which cannot carry out premeiotic DNA replication. Later in meiosis, Mcm4 chromatin association is blocked between meiotic nuclear divisions, presumably accounting for the absence of a second round of DNA replication. Together, these results emphasize similarity between replication mechanisms in mitotic and meiotic cell cycles