An outbreak of Escherichia coli O157:H7 infections following a dairy education school field trip in Washington state, 2015.

On 27 April 2015, Washington health authorities identified Escherichia coli O157:H7 infections associated with dairy education school field trips held in a barn 20-24 April. Investigation objectives were to determine the magnitude of the outbreak, identify the source of infection, prevent secondary illness transmission and develop recommendations to prevent future outbreaks. Case-finding, hypothesis generating interviews, environmental site visits and a case-control study were conducted. Parents and children were interviewed regarding event activities. Odds ratios (OR) and 95% confidence intervals (CI) were computed. Environmental testing was conducted in the barn; isolates were compared to patient isolates using pulsed-field gel electrophoresis (PFGE). Sixty people were ill, 11 (18%) were hospitalised and six (10%) developed haemolytic uremic syndrome. Ill people ranged in age from <1 year to 47 years (median: 7), and 20 (33%) were female. Twenty-seven case-patients and 88 controls were enrolled in the case-control study. Among first-grade students, handwashing (i.e. soap and water, or hand sanitiser) before lunch was protective (adjusted OR 0.13; 95% CI 0.02-0.88, P = 0.04). Barn samples yielded E. coli O157:H7 with PFGE patterns indistinguishable from patient isolates. This investigation provided epidemiological, laboratory and environmental evidence for a large outbreak of E. coli O157:H7 infections from exposure to a contaminated barn. The investigation highlights the often overlooked risk of infection through exposure to animal environments as well as the importance of handwashing for disease prevention. Increased education and encouragement of infection prevention measures, such as handwashing, can prevent illness.

Effect of interferon-ß1b on CXCR4-dependent chemotaxis in T cells from multiple sclerosis patients.

Multiple sclerosis (MS) is an inflammatory, demyelinating and neurodegenerative disease triggered by infiltration of activated T cells into the central nervous system. Interferon (IFN)-ß is an established, safe and effective treatment for patients with relapsing-remitting MS (RRMS). The cytokine can inhibit leucocyte infiltration into the central nervous system; however, little is known about the precise molecular mechanisms. Previously, in vitro application of IFN-ß1b was shown to reduce CXCL12/CXCR4-mediated monocyte migration. Here, we analysed the effects of IFN-ß1b on CXCR4-dependent T cell function. In vitro exposure to IFN-ß1b (1000 U/ml) for 20 h reduced CXCR4-dependent chemotaxis of primary human T cells from healthy individuals and patients with RRMS. Investigating the IFN-ß1b/CXCR4 signalling pathways, we found no difference in phosphorylation of ZAP70, ERK1/2 and AKT despite an early induction of the negative regulator of G-protein signalling, RGS1 by IFN-ß1b. However, CXCR4 surface expression was reduced. Quantitative real time-PCR revealed a similar reduction in CXCR4-mRNA, and the requirement of several hours' exposure to IFN-ß1b supports a transcriptional regulation. Interestingly, T cells from MS patients showed a lower CXCR4 expression than T cells from healthy controls, which was not reduced further in patients under IFN-ß1b therapy. Furthermore, we observed no change in CXCL12-dependent chemotaxis in RRMS patients. Our results demonstrate clearly that IFN-ß1b can impair the functional response to CXCR4 by down-regulating its expression, but also points to the complex in vivo effects of IFN-ß1b therapy.

Corticobasal and ataxia syndromes widen the spectrum of C9ORF72 hexanucleotide expansion disease.

Recently, a hexanucleotide (GGGGCC) repeat expansion in the first intron of C9ORF72 was reported as the cause of chromosome 9p21-linked frontotemporal dementia-amyotrophic lateral sclerosis (FTD-ALS). We here report the prevalence of the expansion in a hospital-based cohort and associated clinical features indicating a wider clinical spectrum of C9ORF72 disease than previously described. We studied 280 patients previously screened for mutations in genes involved in early onset autosomal dominant inherited dementia disorders. A repeat-primed polymerase chain reaction amplification assay was used to identify pathogenic GGGGCC expansions. As a potential modifier, confirmed cases were further investigated for abnormal CAG expansions in ATXN2. A pathogenic GGGGCC expansion was identified in a total of 14 probands. Three of these presented with atypical clinical features and were previously diagnosed with clinical olivopontocerebellar degeneration (OPCD), atypical Parkinsonian syndrome (APS) and a corticobasal syndrome (CBS). Further, the pathogenic expansion was identified in six FTD patients, four patients with FTD-ALS and one ALS patient. All confirmed cases had normal ATXN2 repeat sizes. Our study widens the clinical spectrum of C9ORF72 related disease and confirms the hexanucleotide expansion as a prevalent cause of FTD-ALS disorders. There was no indication of a modifying effect of the ATXN2 gene.

Transthyretin as a potential CSF biomarker for Alzheimer's disease and dementia with Lewy bodies: effects of treatment with cholinesterase inhibitors.

BACKGROUND: Previous studies have indicated that transthyretin (TTR) levels in cerebrospinal fluid (CSF) are altered in depression and dementia. The present study aimed to investigate whether CSF TTR can be used to discriminate between patients with Alzheimer's disease (AD) and patients with dementia with Lewy bodies (DLB) with or without medication, as well as to reveal whether CSF TTR correlates with depression in dementia. METHODS: CSF samples from 59 patients with AD, 13 patients with DLB and 13 healthy controls were collected, and biochemical analysis was performed. Subjects were assessed for the presence of depression. RESULTS: No significant differences in CSF TTR were found between AD, DLB, and control subjects or between depressed and non-depressed dementia patients. Interestingly, we found a significant reduction in CSF TTR (14%) in AD patients who were medicated with cholinesterase inhibitors compared to those AD patients who were not. CONCLUSIONS: Significant reductions in CSF TTR were found after cholinesterase inhibitor treatment in patients with AD compared to untreated individuals. CSF TTR was unaltered in patients with DLB and had no relationship to depression in the present cohort with dementias.

Genetic testing in familial AD and FTD: mutation and phenotype spectrum in a Danish cohort.

Autosomal dominantly transmitted Alzheimer's disease (AD) and frontotemporal dementia (FTD) are genetically heterogeneous disorders. To date, three genes have been identified in which mutations cause early-onset autosomal dominant inherited AD: APP, PSEN1, and PSEN2. Mutations in two genes on chromosome 17, the MAPT and the PGRN genes, are associated with autosomal dominant inherited FTD. The aim of this study was to characterize the mutation spectrum and describe genotype-phenotype correlations in families with inherited dementia. The identification of novel mutations and/or atypical genotype-phenotype correlations contributes to further characterizing the disorders. DNA-samples from the 90 index cases from a Danish referral-based cohort representing families with presumed autosomal dominant inherited AD or FTD were screened for mutations in the known genes with sequencing, denaturing high-performance liquid chromatography (DHPLC) and multiplex ligation-dependent probe amplification (MLPA) techniques. Seven presumed pathogenic mutations (two PSEN1, one PSEN2, one APP, one MAPT, and two PGRN) were identified, including a novel PSEN2 mutation (V393M). No dosage aberrations were identified.

Protein folding sculpting evolutionary change.

Our work suggests that the forces that govern protein folding exert a profound effect on how genotypes are translated into phenotypes and that this in turn has strong effects on evolutionary processes. Molecular chaperones, also known as "heat-shock proteins" (Hsps), promote the correct folding and maturation of many other proteins in the cell. Hsp90 is an abundant and highly specialized chaperone that works on a particularly interesting group of client proteins: metastable signal transducers that are key regulators of a broad spectrum of biological processes. Such proteins often have evolved to finish folding only when they have received a specific signal, such as the binding of a ligand or a posttranslational modification. Importantly, the folding of Hsp90 clients is particularly sensitive to changes in the external and internal environment of the cell. Therefore, Hsp90 is uniquely positioned to couple environmental contingencies to the evolution of new traits. Our work has helped to define two mechanisms by which Hsp90 might influence the acquisition of new phenotypes. First, by robustly maintaining signaling pathways, Hsp90 can buffer the effects of mutations in those pathways, allowing the storage of cryptic genetic variation that is released by stress. In this case, when the Hsp90 buffer is compromised by environmental stress, new traits appear. These traits can also be assimilated, so that they become manifest even in the absence of stress, when genetic recombination and selection enrich causative variants in subsequent generations. Second, Hsp90 can potentiate the effects of genetic variation, allowing new mutations to produce immediate phenotypes. In this case, when Hsp90 function is compromised, new traits are lost. These traits can also be assimilated, so that they are maintained under environmental stress, but this is achieved through new mutations. We have discovered these powerful evolutionary mechanisms in fruit flies, mustard plants, and fungi, but expect them to operate in all eukaryotes. Another line of work relating protein folding to the evolution of new traits involves protein-based hereditary elements known as prions. These produce changes in phenotype through heritable, self-perpetuating changes in protein conformation. Because changes in protein homeostasis occur with environmental stress, prions can be cured or induced by stress, creating heritable new phenotypes that depend on the genetic variation present in the organism. Both prions and Hsp90 provide plausible mechanisms for allowing genetic diversity and fluctuating environments to fuel the pace of evolutionary change. The multiple mechanisms by which protein folding can influence the evolution of new traits provide both a new paradigm for understanding rapid, stepwise evolution and a framework for targeted therapeutic interventions.

A novel presenilin 2 mutation (V393M) in early-onset dementia with profound language impairment.

BACKGROUND: Mutations in the Presenilin 2 gene (PSEN2) are rare causes of Alzheimer's disease (AD). Pathogenic mutations in the genes associated with autosomal dominant inherited AD have been shown to alter processing of the amyloid precursor protein (APP) resulting in a relative increase of the amount of Abeta42 peptide. METHODS AND RESULTS: We present a patient with neuropathologically confirmed early-onset AD characterized by profound language impairment. The patient was heterozygous for a novel missense mutation in exon 11 of the PSEN2 gene leading to a predicted amino acid substitution from valine to methionine in position 393, a conserved residue. However, in vitro expression of PSEN2 V393M cDNA did not result in detectable increase of the secreted Abeta42/40 peptide ratio. The mutation was not found in 384 control individuals tested. CONCLUSIONS: The possible pathogenic nature of the mutation is not clarified. We discuss the limitations of functional PSEN2 studies and the challenges associated with genetic counselling of family members at risk.

Frontotemporal dementia linked to chromosome 3 (FTD-3)--current concepts and the detection of a previously unknown branch of the Danish FTD-3 family.

BACKGROUND: Among patients with onset of dementia below the age of 65 years, frontotemporal dementia (FTD) is the second most prevalent cause, secondary only to Alzheimer's disease. Recent advances in understanding the heterogeneous genetic background for different clinical and neuropathological entities of FTD have involved identification of several new causative genes. METHODS AND RESULTS: We report the finding of a truncating mutation in the CHMP2B gene (c.532-1G>C) in a patient with early onset dementia. The patient was previously not known to be related to the single Danish pedigree known to have this specific mutation. Subsequently he has turned out to represent a new branch of the family with several affected individuals. DISCUSSION: Our findings highlight the need for awareness of the CHMP2B mutation and associated clinical phenotype for neurological assessment in Denmark. Further, we discuss recent advances and current concepts in the understanding of CHMP2B-related dementia.

Alzheimer disease-like clinical phenotype in a family with FTDP-17 caused by a MAPT R406W mutation.

We report clinical, molecular, neuroimaging and neuropathological features of a Danish family with autosomal dominant inherited dementia, a clinical phenotype resembling Alzheimer's disease and a pathogenic mutation (R406W) in the microtubule associated protein tau (MAPT) gene. Pre-symptomatic and affected family members underwent multidisciplinary (clinical, molecular, neuroimaging and neuropathological) examinations. Treatment with memantine in a family member with early symptoms, based on the clinical phenotype and the lack of specific treatment, appears to stabilize the disease course and increase the glucose metabolism in cortical and subcortical areas, as determined by serial [F(18)]FDG-PET scanning before and after initiation of treatment. Neuropathological examination of a second affected and mutation-positive family member showed moderate atrophy of the temporal lobes including the hippocampi. Microscopy revealed abundant numbers of tau-positive neurofibrillary tangles in all cortical areas and in some brainstem nuclei corresponding to a diagnosis of frontotemporal lobe degeneration on the basis of a MAPT mutation. The clinical and genetic heterogeneity of autosomal dominant inherited dementia must be taken into account in the genetic counselling and genetic testing of families with autosomal dominantly inherited dementia in general.

Histopathology and serial, multimodal magnetic resonance imaging in a multiple sclerosis variant.

Defining tools in magnetic resonance imaging (MRI) representing specific pathological processes is needed to understand the complex relationship between inflammation, myelin breakdown, axonal injury and clinical symptoms in multiple sclerosis (MS) and its variants. Here, we describe a case of histologically-defined MS, in which the radiological appearance of the lesion and clinical course support the diagnosis of Balo's concentric sclerosis. Serial magnetization transfer, diffusion tensor imaging and 1H-magnetic resonance spectroscopy, from 14 days to 13 months after biopsy, allow the contextual interpretation of specific pathological changes. In our case, acute inflammation was sensitively traced by fractional anisotropy and increased lactate in spectroscopy. In contrast, magnetization transfer ratio and the apparent diffusion coefficient monitor the sequential loss of tissue in selected rings of the lesion. The delay from the peak of symptoms in a dramatic clinical course to the maximum tissue destruction indicated through MRI suggests that compromise of axonal function may be decisive for the acute clinical situation. This is the first report comparing 1H-magnetic resonance spectroscopy, magnetization transfer and diffusion tensor imaging with histopathology in a patient with Balo's concentric sclerosis.

Depot-specific messenger RNA expression of 11 beta-hydroxysteroid dehydrogenase type 1 and leptin in adipose tissue of children and adults.

OBJECTIVE: To compare expression of messenger RNA (mRNA) coding for the cortisol regenerating enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), and the adipocytokines leptin and resistin in paired biopsies of subcutaneous adipose tissue (SC) and omental adipose tissue (OM) from children. DESIGN: Paired biopsies (SC and OM) were obtained from 54 children (age 0.17-16 years, body mass index (BMI) 12.5-28.3 kg/m(2), BMI standard deviation score (SDS) -2.5-4.5) and 16 adults (age 27-79 years, BMI 19-46 kg/m(2)) undergoing open abdominal surgery. mRNA levels of 11beta-HSD1, leptin and resistin were measured using quantitative real-time polymerase chain reaction (PCR). RESULTS: 11beta-HSD1 mRNA level was higher in OM than in SC (P<0.05), whereas leptin mRNA was higher in SC than in OM (P<0.001). There was no difference in the resistin mRNA level between SC and OM. These results were consistent in children and adults. In children, 11beta-HSD1 mRNA in SC was positively associated with BMI SDS (P<0.05), whereas in OM it was positively associated with age (P<0.05). The association between 11beta-HSD1 expression and age remained significant after adjustment for BMI SDS and gender. Leptin mRNA was positively associated with BMI SDS (SC: P<0.001, OM: P<0.001) but not with age in children. In multiple regression analyses, including anthropometric variables and age, BMI SDS was independently associated with mRNA levels of 11beta-HSD1 (P<0.05) and leptin (P<0.001) in SC. When normal weight and overweight children were analyzed separately, 11beta-HSD1 mRNA levels were positively associated with leptin in OM in the overweight group (P<0.05). CONCLUSION: There are depot-specific differences in mRNA levels of 11beta-HSD1 and leptin in children and adults. The positive association of 11beta-HSD1 mRNA in OM with age may reflect a causal role in visceral fat accumulation during growth. Increasing 11beta-HSD1 and leptin mRNA in SC with increasing BMI SDS could suggest that the risk of metabolic consequences of obesity may be established early in life.

The BDNF-Val66Met polymorphism: implications for susceptibility to multiple sclerosis and severity of disease.

Neurodegeneration following inflammatory injury is considered to be a pathological correlate of irreversible disability in patients with multiple sclerosis. The availability of neurotrophins could influence the probability or rate of disease progression and the time of onset. The BDNF-Val66Met-polymorphism leads to altered intracellular transport and secretion of BDNF, and is thus a logical candidate for a gene that influences susceptibility and, more specifically, the clinical course of multiple sclerosis. In order to test this hypothesis we genotyped the polymorphism in 951 UK multiple sclerosis trio families, but found no evidence for association before (p=0.63) or after stratification for clinical course (p=0.73).

Further delineation of the 22q13 deletion syndrome.

A chromosomal deletion syndrome associated with a 22q13 microdeletion has previously been reported in approximately 75 children. We report six cases from Denmark with a deletion of 22q13. One was cytogenetically visible by conventional karyotyping, one was diagnosed by high resolution karyotyping after the demonstration of low arylsulfatase A activity. Two were diagnosed by high resolution CGH analysis, one was diagnosed by multisubtelomeric FISH analysis and one was diagnosed serendipitously as lack of the control signal in a FISH analysis for 22q11 deletion. One of the cases was a mosaic with 16% of cells showing two signals. The phenotype of the children included: generalized developmental delay, compromised language development, hypotonia, normal or accelerated growth and minor facial dysmorphism. Other features were partial agenesis of the corpus callosum, bilateral ureteropelvic stricture, gastroesophageal reflux and hearing loss. One case had a different phenotype, and showed a deletion as well as a duplication. The extent of the deletion was studied by quantitative PCR analysis of a number of DNA markers in the 22q13 region. The deletions varied in size, extending from 4.0 to 9.0 Mb. The clinical phenotype seemed rather similar although some specific features might be attributable to differences in deletions.

Classification of BRCA1 missense variants of unknown clinical significance.

BACKGROUND: BRCA1 is a tumour suppressor with pleiotropic actions. Germline mutations in BRCA1 are responsible for a large proportion of breast-ovarian cancer families. Several missense variants have been identified throughout the gene but because of lack of information about their impact on the function of BRCA1, predictive testing is not always informative. Classification of missense variants into deleterious/high risk or neutral/low clinical significance is essential to identify individuals at risk. OBJECTIVE: To investigate a panel of missense variants. METHODS AND RESULTS: The panel was investigated in a comprehensive framework that included (1) a functional assay based on transcription activation; (2) segregation analysis and a method of using incomplete pedigree data to calculate the odds of causality; (3) a method based on interspecific sequence variation. It was shown that the transcriptional activation assay could be used as a test to characterise mutations in the carboxy-terminus region of BRCA1 encompassing residues 1396-1863. Thirteen missense variants (H1402Y, L1407P, H1421Y, S1512I, M1628T, M1628V, T1685I, G1706A, T1720A, A1752P, G1788V, V1809F, and W1837R) were specifically investigated. CONCLUSIONS: While individual classification schemes for BRCA1 alleles still present limitations, a combination of several methods provides a more powerful way of identifying variants that are causally linked to a high risk of breast and ovarian cancer. The framework presented here brings these variants nearer to clinical applicability.

Expression of cellular inhibitor of apoptosis protein-2 in human subcutaneous and omental adipose tissue.

OBJECTIVE: In the current study, we addressed the question if there is depot-specific expression of cellular inhibitor of apoptosis protein-2 (cIAP2) already in childhood and if the relative expression changes with age in parallel with increasing risk of developing visceral adiposity. SUBJECTS: Paired samples of human omental (OM) and subcutaneous (SC) adipose tissue were obtained from 23 patients (12 children and 11 adults). METHOD: mRNA level of cIAP2 was determined using reverse transcription-polymerase chain reaction (RT-PCR) and protein expression confirmed by Western blotting. Apoptosis indices were determined by terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein nick-end labelling (TUNEL). RESULTS: cIAP2 mRNA was 1.51-fold higher in OM compared with SC adipose tissue (OM>SC in 20 of 23 subjects; P<0.001). Western blots were in agreement with mRNA expression (OM>SC in nine of 10 subjects, P<0.01). Subgroup analyses showed depot difference in both children (P<0.01) and adults (P<0.05). Contrary to the hypothesis, depot-specific difference in mRNA expression of cIAP2 was significantly higher in children compared with adults (P<0.05). We were unable to demonstrate any difference in the basal apoptosis rate between adipocytes from the two depots. There was no significant association between cIAP2 mRNA expression and BMI or sex. CONCLUSIONS: The results demonstrated for the first time that depot-specific difference in cIAP2 expression is consistent in children and adults. This suggests that the higher expression of cIAP2 in OM than in SC adipose tissue may be due to inherent properties of cells from the two depots. The more pronounced depot-specific difference in children than in adults may reflect a net gain in visceral adipose tissue during growth.

Wild-type PrP and a mutant associated with prion disease are subject to retrograde transport and proteasome degradation.

The cytoplasm seems to provide an environment that favors conversion of the prion protein (PrP) to a form with the physical characteristics of the PrP(Sc) conformation, which is associated with transmissible spongiform encephalopathies. However, it is not clear whether PrP would ever exist in the cytoplasm under normal circumstances. We report that PrP accumulates in the cytoplasm when proteasome activity is compromised. The accumulated PrP seems to have been subjected to the normal proteolytic cleavage events associated with N- and C-terminal processing in the endoplasmic reticulum, suggesting that it arrives in the cytoplasm through retrograde transport. In the cytoplasm, PrP forms aggregates, often in association with Hsc70. With prolonged incubation, these aggregates accumulate in an "aggresome"-like state, surrounding the centrosome. A mutant (D177N), which is associated with a heritable and transmissible form of the spongiform encephalopathies, is less efficiently trafficked to the surface than wild-type PrP and accumulates in the cytoplasm even without proteasome inhibition. These results demonstrate that PrP can accumulate in the cytoplasm and is likely to enter this compartment through normal protein quality-control pathways. Its potential to accumulate in the cytoplasm has implications for pathogenesis.

Strains of [PSI(+)] are distinguished by their efficiencies of prion-mediated conformational conversion.

Yeast prions are protein-based genetic elements that produce phenotypes through self-perpetuating changes in protein conformation. For the prion [PSI(+)] this protein is Sup35, which is comprised of a prion-determining region (NM) fused to a translational termination region. [PSI(+)] strains (variants) with different heritable translational termination defects (weak or strong) can exist in the same genetic background. [PSI(+)] variants are reminiscent of mammalian prion strains, which can be passaged in the same mouse strain yet have different disease latencies and brain pathologies. We found that [PSI(+)] variants contain different ratios of Sup35 in the prion and non-prion state that correlate with different translation termination efficiencies. Indeed, the partially purified prion form of Sup35 from a strong [PSI(+)] variant converted purified NM much more efficiently than that of several weak variants. However, this difference was lost in a second round of conversion in vitro. Thus, [PSI(+)] variants result from differences in the efficiency of prion-mediated conversion, and the maintenance of [PSI(+)] variants involves more than nucleated conformational conversion (templating) to NM alone.

The role of conformational flexibility in prion propagation and maintenance for Sup35p.

The [PSI(+)] factor of Saccharomyces cerevisiae is a protein-based genetic element (prion) comprised of a heritable altered conformation of the cytosolic translation termination factor Sup35p. In vitro, the prion-determining region (NM) of Sup35p undergoes conformational conversion from a highly flexible soluble state to structured amyloid fibers, with a rate that is greatly accelerated by preformed NM fiber nuclei. Nucleated conformational conversion is the molecular basis of the genetic inheritance of [PSI(+)] and provides a new model for studying amyloidogenesis. Here we investigate the importance of structure and structural flexibility in soluble NM. Elevated temperatures, chemical chaperones and certain mutations in NM increase or change its structural content and inhibit or enhance nucleated conformational conversion. We propose that the structural flexibility of NM is particularly suited to allowing heritable protein-based changes in cellular behavior.