13 research outputs found
SUGAR-DIP trial: Oral medication strategy versus insulin for diabetes in pregnancy, study protocol for a multicentre, open-label, non-inferiority, randomised controlled trial
Introduction In women with gestational diabetes mellitus (GDM) requiring pharmacotherapy, insulin was the established first-line treatment. More recently, oral glucose lowering drugs (OGLDs) have gained popularity as a patient-friendly, less expensive and safe alternative. Monotherapy with metformin or glibenclamide (glyburide) is incorporated in several international guidelines. In women who do not reach sufficient glucose control with OGLD monotherapy, usually insulin is added, either with or without continuation of OGLDs. No reliable data from clinical trials, however, are available on the effectiveness of a treatment strategy using all three agents, metformin, glibenclamide and insulin, in a stepwise approach, compared with insulin-only therapy for improving pregnancy outcomes. In this trial, we aim to assess the clinical effectiveness, cost-effectiveness and patient experience of a stepwise combined OGLD treatment protocol, compared with conventional insulin-based therapy for GDM. Methods The SUGAR-DIP trial is an open-label, multicentre randomised controlled non-inferiority trial. Participants are women with GDM who do not reach target glycaemic control with modification of diet, between 16 and 34 weeks of gestation. Participants will be randomised to either treatment with OGLDs, starting with metformin and supplemented as needed with glibenclamide, or randomised to treatment with insulin. In women who do not reach target glycaemic control with combined metformin and glibenclamide, glibenclamide will be substituted with insulin, while continuing metformin. The primary outcome will be the incidence of large-for-gestational-age infants (birth weight >90th percentile). Secondary outcome measures are maternal diabetes-related endpoints, obstetric complications, neonatal complications and cost-effectiveness analysis. Outcomes will be analysed according to the intention-to-treat principle. Ethics and dissemination The study protocol was approved by the Ethics Committee of the Utrecht University Medical Centre. Approval by the boards of management for all participating hospitals will be obtained. Trial results will be submitted for publication in peer-reviewed journals
FMRP is associated to the ribosomes via RNA
The FMR1 transcript is alternatively spliced and generates different
splice variants coding for FMR1 proteins (FMRP) with a predicted molecular
mass of 70-80 kDa. FMRP is widely expressed and localized in the
cytoplasm. To study a possible interaction with other cellular components,
FMRP was isolated and characterized under non-denaturing conditions. Under
physiological salt conditions FMRP appears to have a molecular mass of >
600 kDa, indicating a binding to other cellular components. This
interaction is disrupted in the presence of high salt concentrations. The
dissociation conditions to free FMRP from the complex are similar to the
dissociation of FMRP from RNA as shown before. The binding of FMRP from
the complex is also disrupted by RNAse treatment. That the association of
FMRP to a high molecular weight complex possibly occurs via RNA, is
further supported by the observation that the binding of FMRP, containing
an lle304Asn substitution, to the high molecular weight complex is
reduced. An equal reduced binding of mutated FMRP to RNA in vitro was
observed before under the same conditions. The reduced binding of FMRP
with the lle304Asn substitution further indicates that the interaction to
the complex indeed occurs via FMRP and not via other RNA binding proteins.
In a reconstitution experiment where the low molecular mass FMRP (70-80
kDa) is mixed with a reticulocyte lysate (enriched in ribosomes) it was
shown that FMRP can associate to ribosomes and that this binding most
likely occurs via RNA
Differential expression of FMR1, FXR1 and FXR2 proteins in human brain and testis
Lack of expression of the fragile X mental retardation protein (FMRP)
results in mental retardation and macroorchidism, seen as the major
pathological symptoms in fragile X patients. FMRP is a cytoplasmic
RNA-binding protein which cosediments with the 60S ribosomal subunit.
Recently, two proteins homologous to FMRP were discovered: FXR1 and FXR2.
These novel proteins interact with FMRP and with each other and they are
also associated with the 60S ribosomal subunit. Here, we studied the
expression pattern of the three proteins in brain and testis by
immunohistochemistry. In adult brain, FMR1, FXR1 and FXR2 proteins are
coexpressed in the cytoplasm of specific differentiated neurons only.
However, we observed a different expression pattern in fetal brain as well
as in adult and fetal testis, suggesting independent functions for the
three proteins in those tissues during embryonic development and adult
life
The fragile X-related proteins FXR1P and FXR2P contain a functional nucleolar-targeting signal equivalent to the HIV-1 regulatory proteins
Fragile X syndrome is caused by the absence of the fragile X
mental-retardation protein (FMRP). FMRP and the fragile X-related proteins
1 and 2 (FXR1P and FXR2P) form a gene family with functional similarities,
such as RNA binding, polyribosomal association and nucleocytoplasmic
shuttling. In a previous study, we found that FMRP and FXR1P shuttle
between cytoplasm and nucleoplasm, while FXR2P shuttles between cytoplasm
and nucleolus. The nuclear and nucleolar-targeting properties of these
proteins were investigated further. Here, we show that FXR2P contains in
its C-terminal part, a stretch of basic amino acids 'RPQRRNRSRRRRFR' that
resemble the nucleolar-targeting signal (NoS) of the viral protein Rev.
This particular sequence is also present within exon 15 of the FXR1 gene.
This exon undergoes alternative splicing and is therefore only present in
some of the FXR1P isoforms. We investigated the intracellular distribution
of various FXR1P isoforms with (iso-e and iso-f) and without (iso-d) the
potential NoS in transfected COS cells treated with the nuclear export
inhibitor leptomycin-B. Both iso-e and iso-f showed a nucleolar
localization, as observed for FXR2P; iso-d was detected in the
nucleo-plasm outside the nucleoli. Further, when a labelled 16-residue
synthetic peptide corresponding to the NoS of FXR1P was added to human
fibroblast cultures a clear nucleolar signal was observed. Based on these
data we argue that the intranuclear distribution of FXR2P and FXR1P
isoforms is very likely to be mediated by a similar NoS localized in their
C-terminal region. This domain is absent in some FXR1P isoforms as well as
in all FMRP isoforms, suggesting functional differences for this family of
proteins, possibly related to RNA metabolism in different tissues