Dietary Aromatic Amino Acid Requirements During Early and Late Gestation in Healthy Pregnant Women.

BACKGROUND: Phenylalanine and tyrosine (referred to as total aromatic amino acids; TAAs) are essential for protein synthesis, and are precursors for important catecholamines. Current estimated average requirement (EAR) recommendations for TAA during pregnancy are 36 mg·kg-1·d-1, and has not been experimentally determined. OBJECTIVES: The aim was to determine TAA requirements (dietary phenylalanine in the absence of tyrosine) during early and late gestation using the indicator amino acid oxidation (IAAO, with L-[1-13C]leucine) technique. METHODS: Nineteen healthy pregnant women (age 22-38 y) were studied at a range of phenylalanine intakes (5 to 100 mg·kg-1·d-1) in early (13-19 wk) and/or late (33-39 wk) pregnancy for a total of 51 study days. Graded test intakes were provided as 8 hourly isonitrogenous and isocaloric meals. Breath samples were collected for 13C enrichment analysis on an isotope ratio mass spectrometer. A plasma sample was collected and analyzed for phenylalanine and tyrosine concentrations on an amino acid analyzer. The TAA requirement in early and late pregnancy was calculated using 2-phase linear regression crossover analysis that identified breakpoints in 13CO2 production (the requirement) in response to phenylalanine intakes. RESULTS: TAA requirement during early pregnancy was 44 mg·kg-1·d-1 (95% CI: 28.3, 58.8) and during late pregnancy was 50 mg·kg-1·d-1 (95% CI: 36.1, 63.1). In early and late pregnancy, plasma phenylalanine and tyrosine concentrations rose linearly in response to graded phenylalanine intakes. CONCLUSIONS: Our results suggest that the current EAR of 36 mg·kg-1·d-1 for TAAs is underestimated. When compared with results previously determined in nonpregnant adults, early pregnancy requirements were similar (43 compared with 44 mg·kg-1·d-1, respectively). During late pregnancy, a 14% higher TAA requirement was observed when compared with early pregnancy. The results from this study have potential implications for creating gestation stage-specific TAA recommendations.

Nonsynonymous Polymorphism Counts in Bacterial Genomes: a Comparative Examination.

Genomic data reveal single-nucleotide polymorphisms (SNPs) that may carry information about the evolutionary history of bacteria. However, it remains unclear what inferences about selection can be made from genomic SNP data. Bacterial species are often sampled during epidemic outbreaks or within hosts during the course of chronic infections. SNPs obtained from genomic analysis of these data are not necessarily fixed. Treating them as fixed during analysis by using measures such as the ratio of nonsynonymous to synonymous evolutionary changes (dN/dS) may lead to incorrect inferences about the strength and direction of selection. In this study, we consider data from a range of whole-genome sequencing studies of bacterial pathogens and explore patterns of nonsynonymous variation to assess whether evidence of selection can be identified by investigating SNP counts alone across multiple WGS studies. We visualize these SNP data in ways that highlight their relationship to neutral baseline expectations. These neutral expectations are based on a simple model of mutation, from which we simulate SNP accumulation to investigate how SNP counts are distributed under alternative assumptions about positive and negative selection. We compare these patterns with empirical SNP data and illustrate the general difficulty of detecting positive selection from SNP data. Finally, we consider whether SNP counts observed at the between-host population level differ from those observed at the within-host level and find some evidence that suggests that dynamics across these two scales are driven by different underlying processes.IMPORTANCE Identifying selection from SNP data obtained from whole-genome sequencing studies is challenging. Some current measures used to identify and quantify selection acting on genomes rely on fixed differences; thus, these are inappropriate for SNP data where variants are not fixed. With the increase in whole-genome sequencing studies, it is important to consider SNP data in the context of evolutionary processes. How SNPs are counted and analyzed can help in understanding mutation accumulation and trajectories of strains. We developed a tool for identifying possible evidence of selection and for comparative analysis with other SNP data. We propose a model that provides a rule-of-thumb guideline and two new visualization techniques that can be used to interpret and compare SNP data. We quantify the expected proportion of nonsynonymous SNPs in coding regions under neutrality and demonstrate its use in identifying evidence of positive and negative selection from simulations and empirical data.

Assessing the Effectiveness of a Mental Health Literacy Programme for Refugee Teachers in Malaysia.

BACKGROUND: Children and young refugees often experience negative events that affect their mental health. Their caregivers may also be in the same predicament, implying that the teachers in schools are a potential source of help and support. However, most teachers have little understanding of mental health and are, thus, clueless in helping their students. To address this need, a newly developed one-day mental health literacy programme was conducted among 68 refugee teachers in Malaysia. METHODS: Participants learned the symptoms of mental health issues among children and adolescents in the context of post-trauma, provision of early intervention, and channel for professional supports. They also answered a packet of measurements of mental health literacy before and after the programme. RESULTS: The paired sample t-test showed that participants reported higher willingness to contact with people having mental health problems (t = 2.787, P = 0.008, Cohen's d = 0.394), less stereotypes toward mental illness (t = 4.603, P < 0.001, d = 0.651) and a better understanding of self-help strategies (t = 2.16, P = .036, d = 0.322) than baseline. CONCLUSION: The results of this study offered preliminary empirical evidence on the effectiveness of the programme as a promising channel for alleviating mental health issues among refugees.

A Multicenter, Open-Label Phase II Clinical Trial of Combined MEK plus EGFR Inhibition for Chemotherapy-Refractory Advanced Pancreatic Adenocarcinoma.

PURPOSE: On the basis of preclinical evidence of synergistic activity between MEK and EGFR inhibitors in pancreatic ductal adenocarcinoma (PDAC), we evaluated the safety and efficacy of selumetinib, a MEK1/2 inhibitor, plus erlotinib in patients with previously treated advanced PDAC. EXPERIMENTAL DESIGN: In this single-arm phase II trial, eligible patients received the combination of erlotinib 100 mg plus selumetinib 100 mg daily in 3-week cycles. Study assessments included measurement of clinical outcomes, with a primary endpoint of overall survival, and exploration of potential molecular predictors of treatment benefit. RESULTS: Forty-six patients were enrolled and received a median of two cycles (range, 1-7). Although no objective responses were observed, 19 patients (41%) showed evidence of stable disease for ≥6 weeks, and 13 of 34 patients (38%) had a CA19-9 decline ≥50%. Median progression-free survival was 1.9 months [95% confidence interval (CI), 1.4-3.3 months], with a median overall survival of 7.3 months (95% CI, 5.2-8.0 months). Common adverse events included rash, diarrhea, and nausea/vomiting. Patients with tumors exhibiting an epithelial phenotype (demonstrated by a high level of E-cadherin expression) were more likely to be sensitive to study treatment. Tumor-derived DNA was detectable in plasma from the majority of patients using next-generation digital DNA sequencing, and its relative abundance correlated with tumor burden. CONCLUSIONS: A therapeutic strategy of dual targeted inhibition of the MEK and EGFR pathways shows modest antitumor activity in pancreatic cancer. Specific molecular subtypes may derive greatest benefit from this combination. Further exploration, both with more potent MEK inhibitors and in molecularly enriched patient subsets, is warranted.

A phase I trial of nab-paclitaxel, gemcitabine, and capecitabine for metastatic pancreatic cancer.

BACKGROUND: Substantial antitumor activity has previously been demonstrated with the addition of nab-paclitaxel (Abraxane [Celgene, Summit, NJ]), an albumin-bound formulation of paclitaxel, to gemcitabine in patients with advanced pancreatic cancer. Given preclinical evidence of synergy when a fluoropyrimidine is added to gemcitabine plus a taxane in a sequence-specific schedule, we conducted a phase I study to evaluate the combination of nab-paclitaxel, gemcitabine, and capecitabine administered biweekly in patients with metastatic pancreatic adenocarcinoma. MATERIALS AND METHODS: Patients with previously untreated metastatic pancreatic cancer and an ECOG performance status of 0-1 were eligible to participate. Study design utilized a 3 + 3 dose-escalation schema, with expanded cohort at maximum-tolerated dose (MTD). Treatment was administered in 14-day cycles, with capecitabine given on days 1-7 and both gemcitabine (at fixed-dose rate infusion) and nab-paclitaxel on day 4 of each cycle. Dose-limiting toxicity (DLT) definitions included grade 3-4 hematologic toxicities and grade 2-4 hand-foot syndrome, neuropathy, or diarrhea. RESULTS: Fifteen patients were enrolled across two dose levels. Final MTD was established at nab-paclitaxel 100 mg/m(2), gemcitabine 750 mg/m(2), and capecitabine 750 mg/m(2) twice daily. Patients received a median of four treatment cycles (range 1-16). The most frequent adverse events (any grade) for the entire study cohort included fatigue, rash/hand-foot syndrome, nausea/vomiting, diarrhea, neuropathy, and elevated liver function tests. Ten patients (66.7 %) experienced at least one grade 3-4 adverse event. Grade 3-4 hematologic toxicities were uncommon. Two of 14 evaluable patients (14.3 %) exhibited a partial response, and 6 of 12 patients (50 %) with elevated CA19-9 at baseline had a ≥50 % biomarker decline. CONCLUSION: While well tolerated overall, this regimen demonstrated only modest antitumor activity in patients with metastatic pancreatic cancer. Recognizing the limits of cross-study comparisons and small sample size, these results do not match those reported at MTD in the phase I/II trial of gemcitabine/nab-paclitaxel. The lower doses used in the current study suggest that dose intensity may be a critical aspect to optimize multidrug regimens.

Optimizing the administration of fixed-dose rate gemcitabine plus capecitabine using an alternating-week schedule: a dose finding and early efficacy study in advanced pancreatic and biliary carcinomas.

OBJECTIVES: This multisite study sought to optimize the dosing, schedule, and administration of fixed-dose rate (FDR) gemcitabine plus capecitabine for advanced pancreatic and biliary tract cancers using an alternating-week dose schedule of both agents. METHODS: Patients with previously untreated advanced pancreatic and biliary tract cancers with Eastern Cooperative Oncology Group performance status of 0 or 1 were eligible. For the dose-finding portion, a standard 3+3 dose-escalation schema was used, with the gemcitabine dose kept at 1000 mg/m(2) administered by FDR (10 mg/m(2)/min) on day 1 of each 14-day cycle, and capecitabine given on days 1 to 7 at doses ranging from 800 to 1500 mg/m(2) twice daily. Primary study objective was determination of maximum tolerated dose (MTD). The cohort at MTD was expanded for further efficacy assessment. RESULTS: A total of 45 patients (median age 61 y; 93% pancreatic/7% biliary; 84% with metastatic disease) were enrolled. Median number of cycles received was 11.5. The MTD using this dose schedule was FDR gemcitabine 1000 mg/m(2) plus capecitabine 1000 mg/m(2) bid, due to a high incidence of late hand-foot syndrome observed at the next higher dose level. Most common nonhematologic adverse events related to treatment included nausea/vomiting (overall rate, 64%; all grade 1/2) and hand-foot syndrome (overall rate, 60%; grade 3, 22%). The incidence of grade 3/4 hematologic adverse events was 24%. Six of 41 evaluable patients (14.6%) had a partial response; 18 of 31 patients (58%) with elevated baseline CA 19-9 level had ≥50% biomarker decline during treatment. Estimated median time to tumor progression and overall survival were 5.5 and 9.8 months, respectively (5.5 and 10.1 mo in the metastatic pancreatic cancer cohort). CONCLUSIONS: This dosing schedule of FDR gemcitabine plus capecitabine is active in patients with advanced pancreatobiliary cancers. Given its favorable toxicity profile and convenience, this regimen represents an appropriate front-line option for this patient population and may serve as the foundation on which new investigational agents are added in future trial design.

Microbiological aspects of the investigation that traced the 1998 outbreak of listeriosis in the United States to contaminated hot dogs and establishment of molecular subtyping-based surveillance for Listeria monocytogenes in the PulseNet network.

A multistate outbreak of listeriosis occurred in the United States in 1998 with illness onset dates between August and December. The outbreak caused illness in 108 persons residing in 24 states and caused 14 deaths and four miscarriages or stillbirths. This outbreak was detected by public health officials in Tennessee and New York who observed significant increases over expected listeriosis cases in their states. Subsequently, the Centers for Disease Control and Prevention (CDC) began laboratory characterization of clinical isolates of Listeria monocytogenes by serotyping and restriction fragment length polymorphism analysis using pulsed-field gel electrophoresis (PFGE). For the purpose of this investigation, outbreak-related isolates were defined as those that had a specific AscI-PFGE pattern and indistinguishable or highly similar (no more than 2 band difference in 26 bands) ApaI-PFGE patterns when their DNA was restricted by AscI and ApaI restriction enzymes. Timely availability of molecular subtyping results enabled epidemiologists to separate outbreak cases from temporally associated sporadic cases in the same geographic areas and facilitated the identification of contaminated hot dogs manufactured at a single commercial facility as the source of the outbreak. During the investigation of this outbreak, a standardized protocol for subtyping L. monocytogenes by PFGE was developed and disseminated to public health laboratories participating with CDC's PulseNet network; these laboratories were requested to begin routine PFGE subtyping of L. monocytogenes.

Multistate outbreak of Listeria monocytogenes infection linked to delicatessen turkey meat.

BACKGROUND: Despite a decreasing incidence of listeriosis in the United States, molecular subtyping has increased the number of recognized outbreaks. In September 2000, the New York City Department of Health identified a cluster of infections caused by Listeria monocytogenes isolates with identical molecular subtypes by pulsed-field gel electrophoresis (PFGE) and ribotyping. METHODS: To determine the magnitude of the outbreak and identify risk factors for infection, we notified state health departments and conducted a case-control study. A case was defined as a patient or mother-infant pair infected with Listeria monocytogenes whose isolate yielded the outbreak PFGE pattern. Controls were patients infected with Listeria monocytogenes whose isolate yielded a different PFGE pattern. Patients were asked about food and drink consumed during the 30 days before the onset of illness. RESULTS: Between May and December 2000, there were 30 clinical isolates of Listeria monocytogenes with identical PFGE patterns identified in 11 US states. Cases of infection caused by these isolates were associated with 4 deaths and 3 miscarriages. A case-control study implicated sliced processed turkey from a delicatessen (Mantel-Haenszel odds ratio, 8.0; 95% confidence interval, 1.2-43.3). A traceback investigation identified a single processing plant as the likely source of the outbreak, and the company voluntarily recalled 16 million pounds of processed meat. The same plant had been identified in a Listeria contamination event that had occurred more than a decade previously. CONCLUSIONS: Prevention of persistent L. monocytogenes contamination in food processing plants presents a critical challenge to food safety professionals.