Elevated plasma phospholipid n-3 docosapentaenoic acid concentrations during hibernation.

Factors for initiating hibernation are unknown, but the condition shares some metabolic similarities with consciousness/sleep, which has been associated with n-3 fatty acids in humans. We investigated plasma phospholipid fatty acid profiles during hibernation and summer in free-ranging brown bears (Ursus arctos) and in captive garden dormice (Eliomys quercinus) contrasting in their hibernation patterns. The dormice received three different dietary fatty acid concentrations of linoleic acid (LA) (19%, 36% and 53%), with correspondingly decreased alpha-linolenic acid (ALA) (32%, 17% and 1.4%). Saturated and monounsaturated fatty acids showed small differences between summer and hibernation in both species. The dormice diet influenced n-6 fatty acids and eicosapentaenoic acid (EPA) concentrations in plasma phospholipids. Consistent differences between summer and hibernation in bears and dormice were decreased ALA and EPA and marked increase of n-3 docosapentaenoic acid and a minor increase of docosahexaenoic acid in parallel with several hundred percent increase of the activity index of elongase ELOVL2 transforming C20-22 fatty acids. The highest LA supply was unexpectantly associated with the highest transformation of the n-3 fatty acids. Similar fatty acid patterns in two contrasting hibernating species indicates a link to the hibernation phenotype and requires further studies in relation to consciousness and metabolism.

Measurement of lactate in pleural fluid rapidly identify infection and guide therapy.

BACKGROUND: Measurements of pleural fluid biomarkers for rapid identification of complicated parapneumonic effusion (CPPE) are crucial for optimal management. Previous studies for biomarker evaluation were however based on pleura culture, not modern DNA technique. Lactate has not been thoroughly studied earlier as a potential biomarker in this regard. OBJECTIVES: To evaluate whether the routine biomarkers pH, glucose, lactate dehydrogenase (LDH) measured in pleural fluid in a microbiological well characterised cohort could differentiate simple parapneumonic effusion (SPPE) from CPPE and if pleural fluid lactate could be of additional use in this discrimination. METHODS: Pleural fluid prospectively collected from adult patients (n = 112) with PPE admitted to the Departments of Infectious Diseases (DIDs) at four Stockholm County hospitals were characterised microbiologically with bacterial culture and 16S rDNA sequencing, and biochemically with pH, glucose, LDH and lactate. RESULTS: Forty and seventy two patients were categorised as SPPE/CPPE. The median values between SPPE/CPPE differed significantly for all biomarkers with varying overlap. Receiver operating characteristics (ROC) curves showed the area under the curve (AUC) for pH 0.905 (CI 0.847-0.963), glucose 0.861 (CI 0.79-0.932), LDH 0.917 (CI 0.860-0.974) and lactate 0.927 (CI 0.877-0.977), corresponding to best cut-off levels and sensitivity/specificity for pH of 7.255, 0.819/0.9, glucose 5.35 mmol/L, 0.847/0.775, LDH 9.8 µcat/L, 0.905/0.825 and lactate 4.9 mmol/L, 0.875/0.85. CONCLUSIONS: To distinguish between SPPE/CPPE, pH and LDH performed well, but optimal cut-off values differed from earlier established recommendations. Pleura lactate had the largest AUC of the investigated biomarkers and may be used in the analyses of PPE-staging.

Integration of whole genome sequencing into a healthcare setting: high diagnostic rates across multiple clinical entities in 3219 rare disease patients.

BACKGROUND: We report the findings from 4437 individuals (3219 patients and 1218 relatives) who have been analyzed by whole genome sequencing (WGS) at the Genomic Medicine Center Karolinska-Rare Diseases (GMCK-RD) since mid-2015. GMCK-RD represents a long-term collaborative initiative between Karolinska University Hospital and Science for Life Laboratory to establish advanced, genomics-based diagnostics in the Stockholm healthcare setting. METHODS: Our analysis covers detection and interpretation of SNVs, INDELs, uniparental disomy, CNVs, balanced structural variants, and short tandem repeat expansions. Visualization of results for clinical interpretation is carried out in Scout-a custom-developed decision support system. Results from both singleton (84%) and trio/family (16%) analyses are reported. Variant interpretation is done by 15 expert teams at the hospital involving staff from three clinics. For patients with complex phenotypes, data is shared between the teams. RESULTS: Overall, 40% of the patients received a molecular diagnosis ranging from 19 to 54% for specific disease groups. There was heterogeneity regarding causative genes (n = 754) with some of the most common ones being COL2A1 (n = 12; skeletal dysplasia), SCN1A (n = 8; epilepsy), and TNFRSF13B (n = 4; inborn errors of immunity). Some causative variants were recurrent, including previously known founder mutations, some novel mutations, and recurrent de novo mutations. Overall, GMCK-RD has resulted in a large number of patients receiving specific molecular diagnoses. Furthermore, negative cases have been included in research studies that have resulted in the discovery of 17 published, novel disease-causing genes. To facilitate the discovery of new disease genes, GMCK-RD has joined international data sharing initiatives, including ClinVar, UDNI, Beacon, and MatchMaker Exchange. CONCLUSIONS: Clinical WGS at GMCK-RD has provided molecular diagnoses to over 1200 individuals with a broad range of rare diseases. Consolidation and spread of this clinical-academic partnership will enable large-scale national collaboration.

Expanded Screening of One Million Swedish Babies with R4S and CLIR for Post-Analytical Evaluation of Data.

Sweden has one neonatal screening laboratory, receiving 115 to 120 thousand samples per year. Among the one million babies screened by tandem mass spectrometry from November 2010 until July 2019, a total of 665 babies were recalled and 311 verified as having one of the diseases screened for with this methodology, giving a positive predictive value (PPV) of 47% and an incidence of 1:3200. The PPV was high (41%) already in the first year after start of screening, thanks to the availability of the collaborative project Region 4 Stork database. The PPV is presently 58%. This improvement was achieved by the implementation of second-tier analyses in the screening for methylmalonic aciduria, propionic aciduria, isovaleric aciduria, and homocystinuria, and the employment of various post analytical tools of the Region 4 Stork, and its successor the collaborative laboratory integrated reports.

Evaluation of Nova StatStrip and FreeStyle Precision Pro blood ketone tests using 3-hydroxybutyrate doped samples.

BACKGROUND: The most clinically useful blood ketone in the diagnosis, management, and recovery of diabetes ketoacidosis in both adults and children is 3-hydroxybutyrate. In the absence of laboratory routine methods, several point-of-care methods are in use, but very few clinical evaluations are published. METHODS: This study evaluates linearity and reproducibility of two handheld point-of-care meters for blood 3-hydroxybutyrate measurement for hospital use, Nova StatStrip, and FreeStyle Precision Pro. Whole blood from healthy volunteers was spiked with different concentrations of a 3-hydroxybutyrate solution and tested on the point-of-care instruments. The results were compared with plasma 3-hydroxybutyrate that was analyzed with a laboratory enzymatic end point spectrophotometric reference method. RESULTS: Blood 3-hydroxybutyrate on StatStrip was linear with the reference method up to approximately 4 mmol/L, and FreeStyle was linear up to 6 mmol/L. At higher concentrations, the point-of-care instruments gave falsely too low results, especially the StatStrip meter. The FreeStyle meter had better precision and less bias than StatStrip. CONCLUSION: In the acute setting of diabetes ketoacidosis, blood 3-hydroxybutyrate in the higher ranges should be interpreted with caution as the point-of-care meters are less accurate there.

The bacteriology in adult patients with pneumonia and parapneumonic effusions: increased yield with DNA sequencing method.

The aim of this study was to use a 16S rDNA sequencing method in combination with conventional culture in patients with parapneumonic effusions (PPE) to evaluate the methods, study the microbiological spectrum, and examine the presence of bacteria within the different stages of PPE. Adults with community-acquired pneumonia (CAP) and PPE (n = 197) admitted to the Departments of Infectious Diseases at four hospitals in Stockholm County during 2011-2014 were prospectively studied. All patients underwent thoracentesis. Twenty-seven non-infectious pleural effusions were used as controls. The pleural samples were analyzed with culture, 16S rDNA sequencing, pH, glucose, and lactate dehydrogenase. Microbiological etiology was found in 99/197 (50%) of the patients with mixed infections in 20 cases. The most common pathogens were viridans streptococci (n = 37) and anaerobic bacteria (n = 40). Among the 152 patients with both methods performed, 26/152 (17%) and 94/152 (62%) had bacteria identified with culture and 16S rDNA sequencing respectively (p < 0.001). In 24/26 (92%) culture-positive cases, the same organism was identified by 16S rDNA. All controls were negative in both methods. Among the patients with complicated PPE and complete sampling, bacteria were found in 69/74 patients (93%), all detected with 16S rDNA sequencing, compared to 23/74 (31%) culture-positive samples (p < 0.001). Compared with culture, 16S rDNA sequencing substantially improved the microbiological yield, a microbiological diagnosis was achieved in almost all patients with complicated PPE, and the specificity seemed to be high. 16S rDNA sequencing should be used together with culture in patients with PPE to guide antibiotic therapy.

Newborn screening for sickle cell disease in Europe: recommendations from a Pan-European Consensus Conference.

Sickle Cell Disease (SCD) is an increasing global health problem and presents significant challenges to European health care systems. Newborn screening (NBS) for SCD enables early initiation of preventive measures and has contributed to a reduction in childhood mortality from SCD. Policies and methodologies for NBS vary in different countries, and this might have consequences for the quality of care and clinical outcomes for SCD across Europe. A two-day Pan-European consensus conference was held in Berlin in April 2017 in order to appraise the current status of NBS for SCD and to develop consensus-based statements on indications and methodology for NBS for SCD in Europe. More than 50 SCD experts from 13 European countries participated in the conference. This paper aims to summarise the discussions and present consensus recommendations which can be used to support the development of NBS programmes in European countries where they do not yet exist, and to review existing programmes.

Silencing FLI or targeting CD13/ANPEP lead to dephosphorylation of EPHA2, a mediator of BRAF inhibitor resistance, and induce growth arrest or apoptosis in melanoma cells.

A majority of patients with BRAF-mutated metastatic melanoma respond to therapy with BRAF inhibitors (BRAFi), but relapses are common owing to acquired resistance. To unravel BRAFi resistance mechanisms we have performed gene expression and mass spectrometry based proteome profiling of the sensitive parental A375 BRAF V600E-mutated human melanoma cell line and of daughter cell lines with induced BRAFi resistance. Increased expression of two novel resistance candidates, aminopeptidase-N (CD13/ANPEP) and ETS transcription factor FLI1 was observed in the BRAFi-resistant daughter cell lines. In addition, increased levels of the previously reported resistance mediators, receptor tyrosine kinase ephrine receptor A2 (EPHA2) and the hepatocyte growth factor receptor MET were also identified. The expression of these proteins was assessed in matched tumor samples from melanoma patients obtained before BRAFi and after disease progression. MET was overexpressed in all progression samples while the expression of the other candidates varied between the individual patients. Targeting CD13/ANPEP by a blocking antibody induced apoptosis in both parental A375- and BRAFi-resistant daughter cells as well as in melanoma cells with intrinsic BRAFi resistance and led to dephosphorylation of EPHA2 on S897, previously demonstrated to cause inhibition of the migratory capacity. AKT and RSK, both reported to induce EPHA2 S897 phosphorylation, were also dephosphorylated after inhibition of CD13/ANPEP. FLI1 silencing also caused decreases in EPHA2 S897 phosphorylation and in total MET protein expression. In addition, silencing of FLI1 sensitized the resistant cells to BRAFi. Furthermore, we show that BRAFi in combination with the multi kinase inhibitor dasatinib can abrogate BRAFi resistance and decrease both EPHA2 S897 phosphorylation and total FLI1 protein expression. This is the first report presenting CD13/ANPEP and FLI1 as important mediators of resistance to BRAF inhibition with potential as drug targets in BRAFi refractory melanoma.

MGMT promoter methylation is associated with temozolomide response and prolonged progression-free survival in disseminated cutaneous melanoma.

To investigate the predictive and prognostic value of O(6) -methylguanine DNA methyltransferase (MGMT) inactivation by analyses of promoter methylation in pretreatment tumor biopsies from patients with cutaneous melanoma treated with dacarbazine (DTIC) or temozolomide (TMZ) were performed. The patient cohorts consisted of Belgian and Swedish disseminated melanoma patients. Patients were subdivided into those receiving single-agent treatment with DTIC/TMZ (cohort S, n = 74) and those treated with combination chemotherapy including DTIC/TMZ (cohort C, n = 79). Median follow-up was 248 and 336 days for cohort S and cohort C, respectively. MGMT promoter methylation was assessed by three methods. The methylation-related transcriptional silencing of MGMT mRNA expression was assessed by real-time RT-PCR. Response to chemotherapy and progression-free survival (PFS) and overall survival were correlated to MGMT promoter methylation status. MGMT promoter methylation was detected in tumor biopsies from 21.5 % of the patients. MGMT mRNA was found to be significantly lower in tumors positive for MGMT promoter methylation compared to tumors without methylation in both treatment cohorts (p < 0.005). DTIC/TMZ therapy response rate was found to be significantly associated with MGMT promoter methylation in cohort S (p = 0.0005), but did not reach significance in cohort C (p = 0.16). Significantly longer PFS was observed among patients with MGMT promoter-methylated tumors (p = 0.002). Multivariate Cox regression analysis identified presence of MGMT promoter methylation as an independent variable associated with longer PFS. Together, this implies that MGMT promoter methylation is associated with response to single-agent DTIC/TMZ and longer PFS in disseminated cutaneous melanoma.

Procalcitonin levels in community-acquired pneumonia - correlation with aetiology and severity.

We studied procalcitonin (PCT) levels at hospital admittance and their association with aetiology and severity in patients with community-acquired pneumonia (CAP). Median PCT concentrations were higher in bacteraemic patients than in those without bacteraemia (6.11 µg/L vs 0.34 µg/L, p = 0.0002), in patients with non-bacteraemic pneumococcal aetiology than in those infected with other classic bacteria (1.18 vs 0.18, p = 0.038), and in patients with pneumococcal as compared with viral aetiology (2.43 vs 0.24, p = 0.017). When aetiology, bacteraemia and severity according to the pneumonia severity index (PSI) were included in logistic regression analyses with PCT > 0.5 as a dependent variable, the odds ratio (OR) for non-bacteraemic pneumococcal aetiology was 5.7 (p = 0.008) and 3.0 ( p = 0.1) for PSI 4-5. A separate analysis for bacteraemia and PSI 4-5 showed an OR of 17.5 (p = 0.008) and 2.7 (p = 0.092), respectively. In CAP patients, high PCT seems to be a good marker for invasive disease and pneumococcal aetiology. As a predictor of severity it appears to be less important.

BRAF inhibitors in cancer therapy.

Activating BRAF mutations, leading to constitutive activation of the MAPK signaling pathway, are common in a variety of human cancers. Several small molecule BRAF inhibitors have been developed during the last years and shown promising results in clinical trials, especially for metastatic melanoma, while they have been less effective in colon cancer. Two inhibitors, vemurafenib and dabrafenib, have been approved for treatment of melanoma. Unfortunately, in most patients who initially respond the tumors eventually develop acquired resistance to the BRAF inhibitors. So far, a number of resistance mechanisms have been identified, including secondary NRAS mutations and BRAF alternative splicing, leading to reactivation of the MAPK pathway. Other alterations, both upstream and downstream of BRAF can have the same effect, and activation of alternative pathways can also play a role in resistance to BRAF inhibitors. In addition, intra-tumor heterogeneity with the presence of clones of tumor cells lacking BRAF mutations needs to be considered, since wildtype BRAF can be activated by inhibitors designed to target mutated BRAF. Combination of the BRAF inhibitor dabrafenib with the MEK inhibitor trametinib has significantly prolonged progression free survival compared to dabrafenib alone in metastatic melanoma. Combination treatments of BRAF inhibitors with other agents may not only circumvent or delay resistance, but may also lead to fewer side effects, such as development of secondary squamous tumors. Several clinical trials are underway for many different BRAF mutation positive cancers with BRAF inhibitors alone or in combination with other small molecule inhibitors, immunotherapies or conventional chemotherapy.

KIT, NRAS, BRAF and PTEN mutations in a sample of Swedish patients with acral lentiginous melanoma.

BACKGROUND: Acral lentiginous melanoma (ALM) accounts for <10% of all melanomas in Caucasians. Although the involvement of KIT, NRAS and BRAF mutations is well known in ALM, the impact of these mutations on clinicopathological features has not been established. OBJECTIVE: To define the KIT, NRAS, BRAF and PTEN mutation frequencies in Swedish patients with ALM and to evaluate the impact of mutation status on patient and tumor characteristics. METHODS: Tumor cells were microdissected from 88 primary ALMs and 16 paired metastases and analyzed for KIT, NRAS and BRAF mutations. A subset of 25 ALMs was also evaluated for PTEN mutations. RESULTS: BRAF mutations were identified in 17% of the primary ALMs. Both NRAS and KIT mutations were found at a similar frequency of 15%. Only one of the ALMs that were screened for PTEN harbored a mutation (4%). The KIT, NRAS and BRAF mutation status in paired primary and metastatic ALMs was identical. Patients with BRAF mutated tumors were significantly younger (57 years) than those with BRAF wild-type tumors (73 years, p=0.028). BRAF mutations were significantly more common in females (p=0.011) and more often found in tumors located on the feet (p=0.039). Anatomical site was an independent prognostic factor for overall survival; patients with ALMs on the hands or under fingernails had a better prognosis than those with tumors on the feet or under toenails (p=0.025). CONCLUSION: Our results confirm the presence of KIT, NRAS and BRAF mutations in ALM and provide evidence that mutations in these genes occur at similar frequencies. Our results also show that PTEN is mutated in a small subset of ALM tumors.

Association of MITF and other melanosome-related proteins with chemoresistance in melanoma tumors and cell lines.

Previous studies in cell lines have suggested a role for melanosomes and related protein trafficking pathways in melanoma drug response. We have investigated the expression of six proteins related to melanosomes and melanogenesis (MITF, GPR143, gp100/PMEL, MLANA, TYRP1, and RAB27A) in pretreatment metastases from melanoma patients (n = 52) with different response to dacarbazine/temozolomide. Microphthalmia-associated transcription factor (MITF) and G-protein coupled receptor 143 (GPR143) showed significantly higher expression in nonresponders compared with responders. The premelanosome protein (gp100/PMEL) has been indicated previously in resistance to cisplatin in melanoma cells, but the expression levels of gp100/PMEL showed no association with response to dacarbazine/temozolomide in our clinical material. We also investigated the effects on chemosensitivity of siRNA inhibition of gp100/PMEL in the MNT-1 melanoma cell line. As expected from the study of the tumor material, no effect was detected with respect to response to temozolomide. However, knockdown of gp100/PMEL sensitized the cells to both paclitaxel and cisplatin. Overall, our results suggest that MITF, and several MITF-regulated factors, are associated with resistance to chemotherapy in melanoma and that different MITF targets can be of importance for different drugs.

The Accu-Chek Mobile blood glucose monitoring system used under controlled conditions meets ISO 15197 standards in the hands of diabetes patients.

BACKGROUND: Self-monitoring of blood glucose is a cornerstone of diabetes management. The aim of this study was to evaluate the analytical quality and the ease of use of the Accu-Chek Mobile, a new glucose monitoring system designed for capillary blood testing by diabetic patients. MATERIALS AND METHODS: The performance of the Accu-Chek Mobile was evaluated both in the hands of a scientist and of diabetes patients. The designated comparative method was a hexokinase-based laboratory method (Architect ci8200). Diabetics (N = 88) with previous experience of self-testing were recruited for the study. Patient samples, containing glucose in concentrations mainly between ˜4 and ˜20 mmol/L, were analyzed in duplicates both on the Accu-Chek Mobile and with the comparative method. The patients answered a questionnaire about the ease of use of the meter. RESULTS: The meter yields reproducible readings, with an imprecision CV <5% as required by the American Diabetes Association (ADA). Of the glucose concentrations obtained by both the scientist and the patients, more than 95% of the individual results were within ± 20% of the comparative method, meeting the ISO 15197 accuracy goal, but not the stricter ± 10% ADA goal. CONCLUSION: Accu-Chek Mobile is a user-friendly glucometer that in a normo- and hyperglycemic range fulfils the ISO 15197 accuracy requirement, also in the hands of diabetes patients.

Hippocampal neurons exposed to the environmental contaminants methylmercury and polychlorinated biphenyls undergo cell death via parallel activation of calpains and lysosomal proteases.

Methylmercury (MeHg) and polychlorinated biphenyls (PCBs) are widespread environmental pollutants commonly found as contaminants in the same food sources. Even though their neurotoxic effects are established, the mechanisms of action are not fully understood. In the present study, we have used the mouse hippocampal neuronal cell line HT22 to investigate the mechanisms of neuronal death induced by MeHg, PCB 153, and PCB 126, alone or in combination. All chemicals induced cell death with morphological changes compatible with either apoptosis or necrosis. Mitochondrial functions were impaired as shown by the significant decrease in mitochondrial Ca²+ uptake capacity and ATP levels. MeHg, but not the PCBs, induced loss of mitochondrial membrane potential and release of cytochrome c into the cytosol. Also, pre-treatment with the antioxidant MnTBAP was protective only against cell death induced by MeHg. While caspase activation was absent, the Ca²+-dependent proteases calpains were activated after exposure to MeHg or the selected PCBs. Furthermore, lysosomal disruption was observed in the exposed cells. Accordingly, pre-treatment with the calpain specific inhibitor PD150606 and/or the cathepsin D inhibitor Pepstatin protected against the cytotoxicity of MeHg and PCBs, and the protection was significantly enhanced when the two inhibitors were combined. Simultaneous exposures to lower doses of MeHg and PCBs suggested mostly antagonistic interactions. Taken together, these data indicate that MeHg and PCBs induce caspase-independent cell death via parallel activation of calpains and lysosomal proteases, and that in this model oxidative stress does not play a major role in PCB toxicity.

Mutagenesis and homology modeling of the Tn21 integron integrase IntI1.

Horizontal DNA transfer between bacteria is widespread and a major cause of antibiotic resistance. For logistic reasons, single or combined genes are shuttled between vectors such as plasmids and bacterial chromosomes. Special elements termed integrons operate in such shuttling and are therefore vital for horizontal gene transfer. Shorter elements carrying genes, cassettes, are integrated in the integrons, or excised from them, by virtue of a recombination site, attC, positioned in the 3' end of each unit. It is a remarkable and possibly restricting elementary feature of attC that it must be single-stranded while the partner target site, attI, may be double-stranded. The integron integrases belong to the tyrosine recombinase family, and this work reports mutations of the integrase IntI1 from transposon Tn21, chosen within a well-conserved region characteristic of the integron integrases. The mutated proteins were tested for binding to a bottom strand of an attC substrate, by using an electrophoresis mobility shift assay. To aid in interpreting the results, a homology model was constructed on the basis of the crystal structure of integron integrase VchIntIA from Vibrio cholerae bound to its cognate attC substrate VCRbs. The local stability and hydrogen bonding network of key domains of the modeled structure were further examined using molecular dynamics simulations. The homology model allowed us to interpret the roles of several amino acid residues, four of which were clearly binding assay responsive upon mutagenesis. Notably, we also observed features indicating that IntI1 may be more prone to base-specific contacts with VCRbs than VchIntIA.

Neurodevelopmental toxicity of methylmercury: Laboratory animal data and their contribution to human risk assessment.

Methylmercury (MeHg) is one of the most significant public health hazards. The clinical findings in the victims of the Japanese and Iraqi outbreaks have disclosed the pronounced susceptibility of the developing brain to MeHg poisoning. This notion has triggered worldwide scientific attention toward the long-term consequences of prenatal exposure on child development in communities with chronic low level dietary exposure. MeHg neurodevelopmental effects have been extensively investigated in laboratory animals under well-controlled exposure conditions. This article provides an updated overview of the main neuromorphological and neurobehavioral changes reported in non-human primates and rodents following developmental exposure to MeHg. Different aspects of MeHg's effects on the immature organism are reported, with particular reference to the delayed onset of symptoms and the persistency of central nervous system (CNS) injury/dysfunction. Particular attention is paid to the comparative toxicity assessment across species, and to the degree of concordance/discordance between human and animal data. The contribution of animal studies to define the role of potential effect modifiers and variables on MeHg dose-response relationships is also addressed. The ultimate goal is to discuss the relevance of laboratory animal results, as a complementary tool to human data, with regard to the human risk assessment process.

Human developmental neurotoxicity of methylmercury: impact of variables and risk modifiers.

Methylmercury (MeHg) is a widespread environmental and food toxicant which has long been known to affect neurodevelopment in both humans and experimental animals. Risk assessment for MeHg is mainly based on human data coming from the massive episodes of poisoning in Japan and Iraq, as well as from large scale epidemiological studies concerning childhood development and neurotoxicity in relation to in utero exposure in various fish eating communities around the world. Despite the extensive literature and research, the threshold dose for MeHg neurotoxic effects is still unclear, in particular when it comes to subtle effects on neurobehaviour. In this article clinical and epidemiological findings concerning the neurodevelopmental toxicity of MeHg are reviewed. Much attention is focussed on the potential impact of factors, such as diet and nutrition, gender, pattern of exposure and co-exposure to other neurotoxic pollutants, which may modulate MeHg toxic effects. These factors, together with the notion that some symptoms may ensue or exacerbate with aging, contribute to the difficulties in the definition of safe levels for developmental exposure.

CREB-regulated diurnal activity patterns are not indicative for depression-like symptoms in mice and men.

Activation of the transcription factor CREB by Ser142 phosphorylation is implicated in synchronizing circadian rhythmicity, which is disturbed in many depressive patients. Hence, one could assume that emotional behaviour and neuroendocrinological markers would be altered in CREB(S142A) mice, in which serine 142 is replaced by alanine, preventing phosphorylation at this residue. Moreover, associations of CREB Ser142 and seasonal affective disorder (SAD) might be detectable by the analysis of single-nucleotide polymorphisms (SNPs) in the CREB gene close to the Ser142 residue in SAD patients. However, neither CREB(S142A) mice demonstrate features of depression, nor there is evidence for an association of SAD with the CREB genotypes. Nevertheless, in humans there is an association of a global seasonality score and circadian rhythmicity with the CREB genotypes in healthy control probands, but not SAD patients. This parallels the phenotype of CREB(S142A) mice, presenting alterations of circadian rhythm and light-induced entrainment. Thus it is reasonable to assume that CREB Ser142 represents a molecular switch in mice and men, which is responsible for the (dys)regulation of circadian rhythms.