Inter-laboratory consistency and variability in the buccal micronucleus cytome assay depends on biomarker scored and laboratory experience: results from the HUMNxl international inter-laboratory scoring exercise.

The buccal micronucleus cytome (BMNcyt) assay in uncultured exfoliated epithelial cells from oral mucosa is widely applied in biomonitoring human exposures to genotoxic agents and is also proposed as a suitable test for prescreening and follow-up of precancerous oral lesions. The main limitation of the assay is the large variability observed in the baseline values of micronuclei (MNi) and other nuclear anomalies mainly related to different scoring criteria. The aim of this international collaborative study, involving laboratories with different level of experience, was to evaluate the inter- and intra-laboratory variations in the BMNcyt parameters, using recently implemented guidelines, in scoring cells from the same pooled samples obtained from healthy subjects (control group) and from cancer patients undergoing radiotherapy (treated group). The results indicate that all laboratories correctly discriminated samples from the two groups by a significant increase of micronucleus (MN) and nuclear bud (NBUD) frequencies and differentiated binucleated (BN) cells, associated with the exposure to ionizing radiation. The experience of the laboratories was shown to play an important role in the identification of the different cell types and nuclear anomalies. MN frequency in differentiated mononucleated (MONO) and BN cells showed the greatest consistency among the laboratories and low variability was also detected in the frequencies of MONO and BN cells. A larger variability was observed in classifying the different cell types, indicating the subjectivity in the interpretation of some of the scoring criteria while reproducibility of the results between scoring sessions was very good. An inter-laboratory calibration exercise is strongly recommended before starting studies with BMNcyt assay involving multiple research centers.

Timing of Transversus Abdominis Plane Block and Postoperative Pain Management.

BACKGROUND: Transversus abdominis plane (TAP) blocks using liposomal bupivacaine can reduce postoperative pain and opioid consumption after surgery. The impact of timing of administration of such blocks has not been determined. MATERIALS AND METHODS: A retrospective cohort study of all adult patients that underwent colorectal procedures between January 2013 and October 2015 and received TAP blocks with liposomal bupivacaine at our institution was conducted. The primary outcomes were postoperative pain scores and opioid consumption. Secondary outcomes included postoperative use of non-opioid analgesics as well as total hospital cost of admission and postoperative hospital length of stay. RESULTS: A total of 287 patients were identified and included in the analysis. A total of 71 patients received blocks prior to induction of general anesthesia (pre-ind), 85 patients received blocks after induction of general anesthesia but prior to surgical incision (post-ind) and 131 patients received blocks after completion of surgery (post-op). No significant differences were observed in the postoperative pain scores (either in the first 4 hours or for the entire duration of hospital stay) or opioid consumption between the pre-ind and the post-ind groups. More ketorolac was used in the post-op group compared to the pre-ind group (or= 3.36, 95% CI (1.08, 10.43); p=0.03). CONCLUSION: Our findings suggest that there seems to be no difference if tap blocks with liposomal bupivacaine are performed before or after induction of anesthesia. Patient preference as well as operating room efficiency should be considered when deciding on the timing of these blocks.

DNA methylation of imprinted genes in Mexican-American newborn children with prenatal phthalate exposure.

AIM: Imprinted genes exhibit expression in a parent-of-origin-dependent manner and are critical for child development. Recent limited evidence suggests that prenatal exposure to phthalates, ubiquitous endocrine disruptors, can affect their epigenetic dysregulation. MATERIALS & METHODS: We quantified DNA methylation of nine imprinted gene differentially methylated regions by pyrosequencing in 296 cord blood DNA samples in a Mexican-American cohort. Fetal exposure was estimated by phthalate metabolite concentrations in maternal urine samples during pregnancy. RESULTS: Several differentially methylated regions of imprinted genes were associated with high molecular weight phthalates. The most consistent, positive, and false discovery rate significant associations were observed for MEG3. CONCLUSION: Phthalate exposure in utero may affect methylation status of imprinted genes in newborn children.

Prenatal phthalate exposure and altered patterns of DNA methylation in cord blood.

Epigenetic changes such as DNA methylation may be a molecular mechanism through which environmental exposures affect health. Phthalates are known endocrine disruptors with ubiquitous exposures in the general population including pregnant women, and they have been linked with a number of adverse health outcomes. We examined the association between in utero phthalate exposure and altered patterns of cord blood DNA methylation in 336 Mexican-American newborns. Concentrations of 11 phthalate metabolites were analyzed in maternal urine samples collected at 13 and 26 weeks gestation as a measure of fetal exposure. DNA methylation was assessed using the Infinium HumanMethylation 450K BeadChip adjusting for cord blood cell composition. To identify differentially methylated regions (DMRs) that may be more informative than individual CpG sites, we used two different approaches, DMRcate and comb-p. Regional assessment by both methods identified 27 distinct DMRs, the majority of which were in relation to multiple phthalate metabolites. Most of the significant DMRs (67%) were observed for later pregnancy (26 weeks gestation). Further, 51% of the significant DMRs were associated with the di-(2-ethylhexyl) phthalate metabolites. Five individual CpG sites were associated with phthalate metabolite concentrations after multiple comparisons adjustment (FDR), all showing hypermethylation. Genes with DMRs were involved in inflammatory response (IRAK4 and ESM1), cancer (BRCA1 and LASP1), endocrine function (CNPY1), and male fertility (IFT140, TESC, and PRDM8). These results on differential DNA methylation in newborns with prenatal phthalate exposure provide new insights and targets to explore mechanism of adverse effects of phthalates on human health. Environ. Mol. Mutagen. 58:398-410, 2017. © 2017 Wiley Periodicals, Inc.

miRNAs differentially expressed by next-generation sequencing in cord blood buffy coat samples of boys and girls.

AIM: Differences in children's development and susceptibility to diseases and exposures have been observed by sex, yet human studies of sex differences in miRNAs are limited. MATERIALS & METHODS: The genome-wide miRNA expression was characterized by sequencing-based EdgeSeq assay in cord blood buffy coats from 89 newborns, and 564 miRNAs were further analyzed. RESULTS: Differential expression of most miRNAs was higher in boys. Neurodevelopment, RNA metabolism and metabolic ontology terms were enriched among miRNA targets. The majority of upregulated miRNAs (86%) validated by nCounter maintained positive-fold change values; however, only 21% reached statistical significance by false discovery rate. CONCLUSION: Accounting for host factors like sex may improve the sensitivity of epigenetic analyses for epidemiological studies in early childhood.