RESUMEN

The interest in gluten-free cereal products has increased significantly over the last number of years and there is still a high demand for high quality products. This study aims to establish possible connections between protein properties and dough and bread quality which could advance the knowledge for gluten-free product development. The objective of the present study was to correlate protein properties with bread characteristics. Therefore, a wide range of tests (solubility, emulsifying, foaming, water hydration properties) was performed to characterize a range of food proteins (potato, pea, carob, lupin and soy). Furthermore, the performance of these proteins in a dough matrix (pasting, rheology) and bread formulation (volume, structure, and texture) was analysed. Statistical analysis showed significant (p < 0.05) correlations between protein properties, dough properties and final bread characteristics. The addition of the proteins to the gluten-free bread formulation affected pasting rheological and bread characteristics such as crumb density, crumb hardness and specific volume. The addition of potato and soy protein resulted in the lowest volume with a dense crumb structure and a low consumer acceptance score. However, lupin, pea and carob containing gluten-free breads had a higher specific volume and softer and less dense crumb structure. The protein solubility (r, 0.89; p < 0.01) and its foaming properties (r, 0.97; p < 0.05) were found to be the most important protein properties with correlations significantly with dough properties and bread quality.

Asunto(s)

RESUMEN

OBJECTIVES: Preexisting cognitive impairment is a predictor of cognitive decline after ischemic stroke, but evidence in intracerebral hemorrhage (ICH) is limited. We aimed to determine the prevalence of premorbid cognitive impairment in patients with ICH. MATERIALS AND METHODS: We included patients with acute ICH. Pre-ICH cognitive impairment was determined based on the results of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) that uses information from close relatives. Patients were assessed as having been cognitively impaired with an IQCODE score of ≥3.44; an IQCODE ≥4.00 indicated pre-ICH dementia. CT and MRI images were reviewed to determine the extent of white matter lesions and to measure the radial width of the temporal horn as marker of brain atrophy. We investigated differences of cardiovascular risk factors and imaging data between patients with and without pre-ICH cognitive impairment using correlation analyses, uni- and multivariable regression models. Functional neurological state was assessed using the modified Rankin Scale (mRS). The mRS was dichotomized at the level of 3, and a premorbid mRS of 0-2 was considered as functional independency. RESULTS: Among the 89 participants, median age was 70 years (interquartile range 58-78) and 52 (58.4%) were male. IQCODE indicated pre-ICH cognitive impairment in 18.0% (16 of 89), and 83.1% were functionally independent before ICH. Cognitive impairment was associated with a premorbid mRS≥3 (chi squared test, P=0.009). In multivariable analysis, prior stroke/transient ischemic attack (OR 18.29, 95%-CI 1.945-172.033, P=.011) and hematoma volume (OR 0.90, 95%-CI 0.812-0.991, P=.033) were independently associated with pre-ICH cognitive impairment. CONCLUSIONS: In conclusion, cognitive impairment frequently precedes ICH. A higher frequency of cerebrovascular events suggests a role of vascular processes in the development of cognitive impairment before ICH.

Asunto(s)

RESUMEN

BACKGROUND AND PURPOSE: To determine the rate of peri-interventional silent brain infarcts after left atrial appendage occlusion (LAAO). METHODS: In this prospective, uncontrolled single-center pilot study, consecutive patients with atrial fibrillation undergoing LAAO between July 2013 and January 2016 were included. The Amplatzer Cardiac Plug, WATCHMAN or Amulet device was used. A neurological examination and cranial magnetic resonance imaging (MRI) were performed within 48 h before and after the procedure. MRI was evaluated for new diffusion-weighted imaging (DWI) hyperintensities, cerebral microbleeds (CMBs) and white-matter lesions (WMLs). RESULTS: Left atrial appendage occlusion was performed in 21 patients (mean age, 73.2 ± 9.5 years). Main reasons for LAAO were previous intracerebral hemorrhage (n = 11) and major systemic bleeding (n = 6). No clinically overt stroke occurred peri-interventionally. After the intervention, one patient had a small cerebellar hyperintensity on DWI (4.8%; 95% confidence interval, 0.0-14.3) that was not present on the MRI 1 day before the procedure. Among 11 patients with available MRI just before LAAO, there were no significant changes in the number of CMBs and the severity of WMLs after LAAO. CONCLUSIONS: This study of peri-interventional MRI in LAAO suggests a low rate of silent peri-procedural infarcts in this elderly population. Confirmation in larger studies is needed.

Asunto(s)

RESUMEN

BACKGROUND AND PURPOSE: Cerebral microbleeds (CMBs) are associated with an increased risk of intracerebral hemorrhage. The impact of oral anticoagulation (OAC) on CMBs is not well characterized. Our aim was to assess the prevalence of CMBs in stroke and transient ischaemic attack (TIA) patients with atrial fibrillation (AF) and to analyze the implications of previous treatment with OAC. METHODS: In this retrospective analysis on data from a prospectively recruiting stroke registry, patients with ischaemic stroke or TIA with brain magnetic resonance imaging including susceptibility weighted imaging were consecutively enrolled during a 3-year period. For each patient cardiovascular risk factors, AF history and recent diagnosis of AF, present use of OAC and antiplatelets, the National Institute of Health Stroke Scale and the premorbid modified Rankin Scale score were recorded. Two independent raters identified CMBs according to consensus criteria. CMB location was classified as lobar, deep or in the posterior fossa. RESULTS: In all, 785 patients (mean age 63.9 ± 14.2 years) were included. At least one CMB was detected in 186 (23.7%) patients. CMBs were significantly more frequent in patients with AF (30.5% vs. 22.4%). Patients with previous OAC treatment were more likely to have CMBs (36.7% vs. 22.8%, P = 0.03) and abundant CMBs (n > 10) were more frequent in anticoagulated patients even after adjustment for age. However, age was the only independent factor predicting CMBs (P = 0.001). CONCLUSIONS: Cerebral microbleeds are common in elderly AF patients with acute ischaemic stroke. Previous OAC is associated with a higher number of CMBs predominantly in the lobar location. Establishing a causal relationship requires prospective longitudinal investigation.

Asunto(s)

RESUMEN

BACKGROUND AND PURPOSE: Chronic kidney disease (CKD) is associated with a higher risk of stroke and atrial fibrillation (AF). There are limited data on the comorbidity of renal dysfunction and AF in stroke patients. Our aim was to determine the frequency of kidney dysfunction in ischaemic stroke patients with and without AF. METHODS: In a prospectively collected, single center cohort of acute ischaemic stroke and transient ischaemic attack (TIA) patients, glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease equation on admission. Renal function was graded into five categories (cat.): cat. 1, eGRF ≥90 ml/min/1.73 m(2); cat. 2, 60-89; cat. 3, 30-59; cat. 4, 15-29; cat. 5, <15. The diagnosis of AF was based on medical history, a 12-lead electrocardiogram (ECG) and 24-h Holter or continuous ECG monitoring. RESULTS: In total, 2274 patients (1727 stroke, 547 TIA; median age 71.0) were included. Median eGFR was 78.6 ml/min/1.73 m(2) (interquartile range 61/95); 21.1% were in cat. 3, 2.1% in cat. 4, 0.7% in cat. 5. In all, 535 patients (23.5%) suffered from AF; 28.0% of these were in cat. 3, 2.6% and 0.8% in cat. 4 and cat. 5, respectively. In multivariable analysis, age [odds ratio (OR) 1.1], diabetes (OR 1.8), heart failure (OR 1.7) and AF (OR 1.4) were independently associated with kidney dysfunction (eGFR < 60). CONCLUSIONS: Renal dysfunction is far more common in stroke patients than in the general population and more common in AF-related stroke. These findings may have implications for the choice of anticoagulants.

Asunto(s)

RESUMEN

BACKGROUND AND PURPOSE: Cognitive deficits are common following stroke. Cognitive function in the acute stroke setting is a predictive factor for mid-term outcome. The Montreal Cognitive Assessment (MoCA) is a screening tool for cognitive impairment. The feasibility of MoCA in the acute phase of stroke was evaluated and factors predictive of cognitive impairment were determined. METHODS: In this prospective, single-centre, explorative and observational study consecutive patients with ischaemic (IS) or haemorrhagic (ICH) stroke were enrolled between March 2011 and September 2012. The routine work-up for each patient encompassed assessment of cardiovascular risk factors, the National Institutes of Health Stroke Scale (NIHSS) and the pre-morbid modified Rankin Scale (mRS) score. Cognitive performance was measured using the German version of the MoCA within the first days of admission. A MoCA score of <26 was considered to indicate cognitive impairment. RESULTS: Between March 2011 and September 2012 a total of 842 patients with IS (89.0%) and ICH (11.0%) were enrolled in our study. MoCA was feasible in 678/842 patients (80.5%). Factors independently associated with non-feasibility were stroke severity (NIHSS), pre-morbid functional status (mRS), age and lower educational level. Mean MoCA was 21.4 (SD 5.7). A total of 498/678 (73.5%) patients appeared cognitively impaired (<26/30). Independent predictive factors for a lower MoCA score were age, educational level, stroke severity (NIHSS) and pre-morbid functional status (mRS). CONCLUSIONS: In the acute phase of stroke, MoCA is feasible in about 80% of eligible patients. At this stage, MoCA identifies a cognitive impairment in 75% of patients.

Asunto(s)

RESUMEN

BACKGROUND AND PURPOSE: Oral anticoagulation (OAC) is an effective preventive therapy for ischemic stroke in atrial fibrillation (AF). The management of anticoagulation in AF patients with previous intracerebral hemorrhage (ICH) is challenging. The aim of this study was to determine the prevalence of AF after acute ICH in a consecutive monocenter cohort, and to document the subsequent management with respect to OAC. METHODS: Consecutive patients with spontaneous ICH were prospectively included within 19 months. Diagnosis of AF was based on medical history, 12-lead electrocardiogram (ECG), 24-h and continuous ECG monitoring. CHADS2 scores and patient medication were recorded at admission and after 3 months. Additionally, after 3 months mortality, the management of anticoagulation and a newly detected AF were assessed. RESULTS: In total, 206 ICH patients were eligible for data analysis. After 3 months, AF had been diagnosed in 64/206 ICH patients (31.1%). Mortality after 3 months was higher in patients with AF in univariate analysis (45.3% vs. 31.0%). After adjusting for comorbidities and OAC use, AF did not remain an independent predictor for mortality. In total, 35 patients with AF survived 3 months. Of these, CHADS2 score was 2 (2/3, median, interquartile range (IQR)) and 27/35 patients had an indication for OAC with respect to the CHADS2 score, but only 25.7% had been (re-)started on OAC. No consistent factors for deciding whether to initiate OAC treatment could be identified. CONCLUSIONS: Atrial fibrillation is a frequent comorbidity in patients suffering an ICH. Our findings underline the prevailing uncertainty regarding the anticoagulation management of AF after ICH.

Asunto(s)

RESUMEN

Intracerebral hemorrhage (ICH) is the most devastating complication of oral anticoagulation (OAC). As the number of patients on long-term OAC is expected to rise, the proportion of intracerebral hemorrhage related to OAC (OAC-ICH) in relation to spontaneous ICH (spont-ICH) is expected to increase as well. We determined the proportion of OAC-ICH in consecutive stroke patients and explored differences between OAC-ICH and spont-ICH regarding initial volume, hematoma expansion and outcome. Our prospective study consecutively enrolled patients with supra- and infratentorial ICH. The National Institute of Health Stroke Scale Score and the modified Rankin Scale (mRS) score at baseline and after 3 months, medical history and demographic variables were recorded. All admission and follow-up CTs/MRIs were analysed regarding ICH volume using the ABC/2-method. Intraventricular hemorrhage (IVH) was quantified using the Graeb score. Within 19 months, 2,282 patients were admitted to our ER. 206 ICH patients were included. Overall, 24.8 % of all ICH were related to OAC. Compared to patients with spont-ICH, OAC-ICH patients were older (p = 0.001), more frequently had initial extension of ICH into the ventricles (p = 0.05) or isolated primary IVH (p = 0.03) and a higher Graeb score upon admission (p = 0.01). In contrast, initial ICH volume (p = 0.16) and ICH expansion (p = 0.9) in those receiving follow-up imaging (n = 152) did not differ between the two groups. After correction for age, there was a trend towards poorer outcome in OAC-ICH (p = 0.08). One-fourth of all ICH are related to OAC. Initial extension of ICH into the ventricles and primary IVH are more frequent in OAC-ICH. The rate of hematoma expansion in OAC-ICH patients is similar to non-anticoagulated ICH patients.

Asunto(s)

RESUMEN

BACKGROUND AND PURPOSE: Detecting paroxysmal atrial fibrillation (pAF) soon after acute cerebral ischaemia has a major impact on secondary stroke prevention. Recently, the STAF score, a composite of clinical and instrumental findings, was introduced to identify stroke patients at risk of pAF. We aimed to validate this score in an independent study population. METHODS: Consecutive patients admitted to our stroke unit with acute ischaemic stroke were prospectively enrolled. The diagnostic work-up included neuroimaging, neuroultrasound, baseline 12-channel electrocardiogram (ECG), 24-h Holter ECG, continuous ECG monitoring, and echocardiography. Presence of AF was documented according to the medical history of each patient and after review of 12-lead ECG, 24-h Holter ECG, or continuous ECG monitoring performed during the stay on the ward. Additionally, a telephone follow-up visit was conducted for each patient after 3 months to inquire about newly diagnosed AF. Items for each patient-age, baseline NIHSS, left atrial dilatation, and stroke etiology according to the TOAST criteria - were assessed to calculate the STAF score. RESULTS: Overall, 584 patients were enrolled in our analysis. AF was documented in 183 (31.3%) patients. In multivariable analysis, age, NIHSS, left atrial dilatation, and absence of vascular etiology were independent predictors for AF. The logistic AF-prediction model of the STAF score revealed fair classification accuracy in receiver operating characteristic curve analysis with an area under the curve of 0.84. STAF scores of ≥5 had a sensitivity of 79% and a specificity of 74% for predicting AF. CONCLUSION: The value of the STAF score for predicting the risk of pAF in stroke patients is limited.

Asunto(s)

RESUMEN

Major depression and the metabolic syndrome (MetS) are interacting clinical conditions influenced by genetic susceptibility. For both disorders, impaired serotonergic neurotransmission in specific brain areas has been suggested. This led us to investigate whether variants in the gene coding for tryptophan hydroxylase 2 (TPH2), the brain-specific and rate-limiting enzyme for serotonin biosynthesis, might be predictive for an increased liability for the development of MetS in depressed patients. In a case-control study consisting of 988 patients with recurrent unipolar depression (RUD) and 1023 psychiatric healthy controls, MetS components were ascertained according to the International Diabetes Foundation criteria. A total of 41 single nucleotide polymorphisms fully covering the TPH2 gene region were genotyped in stage 1 (300 patients/300 controls), resulting in significant genetic associations of polymorphisms located in exon 7 and intron 8 of TPH2 and the occurrence of MetS in depressed patients after correction for age, gender and multiple testing (51 RUD-MetS/179 RUD-non-MetS). We were able to confirm the significant association of rs17110690 in stage 2 (688 patients/723 controls; 110 RUD-MetS/549 RUD-non-MetS) and to link risk-genotypes and risk-haplotypes for MetS to lower TPH2 mRNA expression and to lower 5-hydroxyindoleacetic acid levels in cerebrospinal fluid previously reported in functional studies. Our findings suggest that TPH2 polymorphisms characterize a subgroup of depressed patients who are especially prone to develop metabolic disorders induced by a genotype-dependent impairment of serotonergic neurotransmission. Identifying depressed patients at high risk for MetS using genetic variants could have direct clinical impact on individualized disease management and prevention strategies.

Asunto(s)

RESUMEN

The contribution of the Wada test (intracarotid amytal procedure, IAP) to predicting postoperative memory outcome in left temporal lobe epilepsy (LTLE) is becoming increasingly controversial when preoperative neuropsychological evaluation and MRI findings are available. We retrospectively analyzed 59 patients with LTLE who underwent en bloc temporal lobe resection. All patients had valid bilateral IAP test results, complete pre- and postoperative neuropsychological evaluation, and MRI grading on a 5-point scale integrating T 2 signal increase and degree of atrophy. Thirty percent of patients showed postoperative memory decline. Multiple regression analysis revealed that significant predictors of decline [F(2.56)=22.71, P<0.001, r(2)=0.448] included preoperative memory learning score [t=-5.89, P<0.001] and MRI classification [t=3.10, P<0.003], but not IAP scores. The IAP is of no added value in the prediction of postoperative memory outcome in LTLE in the presence of comprehensive neuropsychological and MRI data.

Asunto(s)

RESUMEN

Severe stroke leads to subsequent cerebral oedema. Patients with severe stroke develop midline shift (MLS) which can be measured by transcranial duplex sonography (TCD). We measured MLS with TCD in 30 patients with large infarction in the territory of the middle cerebral artery (MCA). All of the examined patients had intracranial pressure (ICP) measure devices and the ICP at the time of the TCD was recorded. MLS was also determined on CT scan on day 4. Ten of the 30 patients were treated with hypothermia. We also determined matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) in serum by zymography. MLS measured by TCD correlated significantly with MLS on CT. In addition there was a strong correlation between the ICP measured at the time of TCD and MLS. In patients treated with hypothermia MLS was less pronounced. MMP9 and MMP2 showed a characteristic time course and had strong associations with MLS. We confirm earlier reports that TCD is a reliable noninvasive method for serially monitoring patients with intracranial lesions. Hypothermia reduces MMP9 activity as well as MLS. TCD may reduce the need for repetitive CT scans in neurological critically ill patients.

Asunto(s)

Asunto(s)

RESUMEN

BACKGROUND AND PURPOSE: Ischemic stroke provokes a systemic inflammatory response. The purpose of this study was to characterize this response on the gene expression level in circulating mononuclear leukocytes from acute ischemic stroke (AIS) patients. METHODS: RNA from peripheral blood mononuclear cells (PBMCs) of AIS patients (24 + 2 hours after onset of symptoms) was analyzed with Affymetrix U133A GeneChips using a pooled design. We compared the gene expression signature from AIS patients (n = 20), stroke survivors (n = 15), patients with acute traumatic brain injury (ATBI, n = 15) and healthy control subjects without vascular risk factors (n = 15). RESULTS: Expression levels of 9682 probe sets with present calls on each GeneChip were compared. Between AIS patients and stroke survivors or between AIS patients and ATBI patients there were no significant differences in expression values of single genes after correction for multiple testing. However, comparison of the PBMC expression profiles from AIS patients and healthy subjects revealed significantly different expression (p = 0.012) of a single probe set, specific for phosphodiesterase 4 D (PDE4D). In order to detect modest expression differences in multiple genes with a presumed cumulative effect we studied the gene expression of functional groups of genes by global statistical tests. Analysis of 11 gene groups revealed differential expression between AIS patients and healthy subjects for genes involved in the inflammatory response (GeneOntology GO:0006954). Genes encoding the N-formyl peptide receptor-like 1 (FPRL1), interleukin-1 receptor antagonist (IL1RN) and complement component 3a receptor 1 (C3AR1) contributed most to the observed difference. CONCLUSIONS: This transcriptome analysis did not identify significant changes between circulating mononuclear cells from AIS patients 24 hours after stroke and closely matched stroke survivors. However, comparing AIS patients with healthy control subjects revealed measurable differences in PDE4D and in inflammatory response genes when considered as a set.

Asunto(s)

RESUMEN

The effects of disjunctive environmental deprivation combined with a single methamphetamine (MA) challenge on postnatal maturation of the serotonin (5-HT) innervation pattern in cerebral cortex of gerbils were studied. Gerbils were assigned to either enriched (ER) or impoverished (IR) environmental rearing conditions. On postnatal day 110, 5-HT was immunostained. The 5-HT innervation pattern of the brain was qualitatively evaluated and provided in graphic form. The densities of 5-HT fibres were quantified in areas of prefrontal, insular, frontal, parietal, and entorhinal cortices of the right hemisphere using digital image analysis. The early MA challenge led to an overshoot of the fibre density in medial and orbital prefrontal cortex and entorhinal cortex of ER animals. IR animals mostly resisted MA effects except of a restraint of the innervation of the insular cortex. In comparison to enriched rearing, restricted rearing caused overshoot maturation of 5-HT innervation in insular and entorhinal cortices. The present data provide evidence for a region-specific postnatal vulnerability of the maturing 5-HT innervation, namely in association cortices. In contrast, both sensory and motor cortices showed no significant changes at all. The results are discussed in context with previously presented findings of alterations of the cortical dopamine innervation depending on both epigenetic factors. In conclusion, both experimental variables together give new insight into raphe-cortical plasticity that may contribute to a better understanding of the role of 5-HT fibre systems in structural maturation of the cortex. Postnatal environment may be involved in individual vulnerability of a variety of mental disorders during adolescence and aging.

Asunto(s)

RESUMEN

B-Myb is a highly conserved member of the Myb transcription factor family. The primary transcript of the B-myb gene is spliced alternatively in two mRNAs which either contain or lack a sequence corresponding to the so-called exon 9A of c-myb. Recent studies showed that full-length B-Myb containing the exon 9A encoded amino acids is a cell cycle regulated transcription factor whose activity is stimulated by cyclin A/Cdk 2-dependent phosphorylation at the carboxyl-terminus of B-Myb. We have now investigated in more detail the transactivation potential of the shorter isoform of B-Myb lacking exon 9A. Here, we show that B-Myb lacking exon 9A has no transactivation activity even in the presence of cyclin A. This inactivity of the shorter isoform of B-Myb is not due an improper subcelluar localization. Our work suggests that B-Myb lacking exon 9A may act as an inhibitor for full-length B-Myb mediated transactivation. Furthermore, by analysing the transactivation potential of Gal4/B-Myb fusion proteins we have identified the amino-terminal part of the exon 9A as the principal transactivation domain of full-length B-Myb. The results presented here demonstrate that B-myb encodes both an activator and an inhibitor of transcription and, thus, reveal an additional level of regulation of B-Myb activity beside the known cyclin dependent mechanisms.

Asunto(s)

RESUMEN

We investigate the role of plastoquinone (PQ) diffusion in the control of the photosynthetic electron transport. A control analysis reveals an unexpected flux control of the whole chain electron transport by photosystem (PS) II. The contribution of PSII to the flux control of whole chain electron transport was high in stacked thylakoids (control coefficient, CJ(PSII) =0.85), but decreased after destacking (CJ(PSII)=0.25). From an 'electron storage' experiment, we conclude that in stacked thylakoids only about 50 to 60% of photoreducable PQ is involved in the light-saturated linear electron transport. No redox equilibration throughout the membrane between fixed redox groups at PSII and cytochrome (cyt) bf complexes, and the diffusable carrier PQ is achieved. The data support the PQ diffusion microdomain concept by Lavergne et al. [J. Lavergne, J.-P. Bouchaud, P. Joliot, Biochim. Biophys. Acta 1101 (1992) 13-22], but we come to different conclusions about size, structure and size distribution of domains. From an analysis of cyt b6 reduction, as a function of PSII inhibition, we conclude that in stacked thylakoids about 70% of PSII is located in small domains, where only 1 to 2 PSII share a local pool of a few PQ molecules. Thirty percent of PSII is located in larger domains. No small domains were found in destacked thylakoids. We present a structural model assuming a hierarchy of specific, strong and weak interactions between PSII core, light harvesting complexes (LHC) II and cyt bf. Peripheral LHCII's may serve to connect PSII-LHCII supercomplexes to a flexible protein network, by which small closed lipid diffusion compartments are formed. Within each domain, PQ moves rapidly and shuttles electrons between PSII and cyt bf complexes in the close vicinity. At the same time, long range diffusion is slow. We conclude, that in high light, cyt bfcomplexes located in distant stromal lamellae (20 to 30%) are not involved in the linear electron transport.

Asunto(s)

RESUMEN

The frequency of motor vehicle and working accidents was analyzed by means of a strictly anonymous questionnaire in 156 patients with sleep apnea syndrome (SAS) and in 160 age-gender matched controls. In the SAS group 12.4% of all drivers had motor vehicle accidents as compared to 2.9% in the control group (p<0.005). The motor vehicle accident rate was 13.0 per million km in patients with more severe SAS (AHI > 34/h, n=78) as compared to 1.1 in patients with milder SAS (AHI 10-34/h, n=78) (p<0.05), and 0.78 in control group (p<0.005), respectively. The accident rates in both patients and the control group were also greater than the rate of 0.02 "accidents due to sleepiness" per one million km in the Swiss driving population as reported by official statistics. During treatment with nasal continuous airway pressure (nCPAP) in 85 SAS patients, the motor vehicle accident rate dropped from 10.6 to 2.7 per million km (p<0.05). We conclude that patients with moderate to severe SAS have an up to fifteen-fold risk increase of motor vehicle accidents that constitutes a serious and often underestimated hazard on the roads, which can be reduced by adequate treatment.

Asunto(s)

RESUMEN

Evidence obtained during recent years suggests that B-Myb, a highly conserved member of the Myb transcription factor family, plays a key role in cell proliferation. We have shown previously that the activity of B-Myb is stimulated by cyclin A/Cdk2-dependent phosphorylation of the carboxyl-terminus of B-Myb. We have now investigated in more detail the effect of other cyclins on B-Myb. Here, we show that cyclin D1, in contrast to cyclin A, strongly inhibits the activity of B-Myb. This inhibitory effect does not involve increased phosphorylation of B-Myb but seems to rely on the formation of a specific complex of B-Myb and cyclin D1. Our work identifies B-Myb as an interacting partner for cyclin D1 and suggest that the activity of B-Myb during the cell cycle is controlled by the antagonistic effects of cyclin D1 and A. The results presented here suggest a more general role of cyclin D1 as regulator of transcription in addition to the known effect on RB phosphorylation.

Asunto(s)

RESUMEN

B-myb is a highly conserved member of the myb proto-oncogene family that encodes a ubiquitously expressed 110-kDa sequence-specific DNA-binding protein. Transactivation of Myb-inducible promoters by B-Myb is repressed by a regulatory domain located at the C-terminus of the protein. Cyclin A/Cdk2-mediated phosphorylation apparently releases the negative constraint and triggers B-Myb transactivation potential. Two-dimensional tryptic phosphopeptide analysis indicated that the majority of the sites phosphorylated in vivo are targeted in vitro by cyclin A/Cdk2. Six sites in B-Myb fulfil the requirements for recognition by Cdk2. Using point mutation of the phosphorylation sites to nonphosphorylatable amino acids, we show that five of these sites are targets for Cdk2 in vivo. Mutation of one of these residues (T524) to alanine diminished the ability of B-Myb to promote transcription of a reporter gene, suggesting that phosphorylation of B-Myb at this site is important for the regulation of its activity by cyclin A/Cdk2.

Asunto(s)