Occurrence and removal of legacy plasticizers and flame retardants through a drinking water treatment plant.

The occurrence of thirty-four flame retardants and plasticizers throughout treatment steps in a drinking water treatment plant (DWTP) was analyzed to assess removal efficiencies of filtration, ultraviolet (UV) treatment, and chlorination. Legacy compounds and replacements were included to compare their presence and persistence. Twenty-four-hour composite sampling, offset to account for retention time, was performed at a direct filtration DWTP in Montreal, Canada over a three-day period. Polybrominated diphenyl ethers (PBDEs), considered legacy flame retardants, were infrequently detected or at concentrations <1 ng/L. When overall removal efficiencies could be calculated, the removal of ∑7PBDEs was 49 and 94 % for days 2 and 3, respectively. No removal could be calculated on day 1 as PBDEs were only detected in finished drinking water. Higher brominated PBDEs BDE-183 and BDE-154 were only detected in raw water. Organophosphate esters (OPEs), considered replacement flame retardants, were frequently detected in all water samples. The total average concentration of ∑15OPes was 501 ng/L in raw water and 162 ng/L in drinking water, with an average removal efficiency of 67 %. OPEs were mainly removed during filtration, with TCIPP, TDCIPP, and TPHP showing statistically significant removal of 76, 84, and 95 %, respectively. The total average concentration of ∑8plasticizers was 2938 ng/L in raw water and 116 ng/L in drinking water. All plasticizers, except for metabolite MEHP, had significant removal from filtration, and the overall removal of plasticizers ranged from 20 % for DEP to 99 % for DEHP. Drinking water treatment decreases the concentration of these contaminants in drinking water but was less effective in removing flame retardants than plasticizers, as indicated by their higher number of PBDEs detected and higher concentrations of OPEs measured. To our knowledge, it is the first report of the removal of PBDEs, OPE metabolites and plasticizer replacements (DEHA, DIDA, DINCH, DINP) during drinking water treatment.

Toxic Tire Wear Compounds (6PPD-Q and 4-ADPA) Detected in Airborne Particulate Matter Along a Highway in Mississippi, USA.

Tire wear particles (TWPs) are a major category of microplastic pollution produced by friction between tires and road surfaces. This non-exhaust particulate matter (PM) containing leachable toxic compounds is transported through the air and with stormwater runoff, leading to environmental pollution and human health concerns. In the present study, we collected airborne PM at varying distances (5, 15 and 30 m) along US Highway 278 in Oxford, Mississippi, USA, for ten consecutive days using Sigma-2 passive samplers. Particles (~ 1-80 µm) were passively collected directly into small (60 mL) wide-mouth separatory funnels placed inside the samplers. Particles were subsequently subjected to solvent extraction, and extracts were analyzed for TWP compounds by high resolution orbitrap mass spectrometry. This pilot study was focused solely on qualitative analyses to determine whether TWP compounds were present in this fraction of airborne PM. The abundance of airborne TWPs increased with proximity to the road with deposition rates (TWPs cm-2 day-1) of 23, 47, and 63 at 30 m, 15 m, and 5 m from the highway, respectively. Two common TWP compounds (6PPD-Q and 4-ADPA) were detected in all samples, except the field blank, at levels above their limits of detection, estimated at 2.90 and 1.14 ng L-1, respectively. Overall, this work suggests airborne TWPs may be a potential inhalation hazard, particularly for individuals and wildlife who spend extended periods outdoors along busy roadways. Research on the bioavailability of TWP compounds from inhaled TWPs is needed to address exposure risk.

Fast and simplified quantitative multiresidue analytical method for pesticides in surface waters by UHPLC-MS/MS with online sample preparation.

A quantitative multiresidue analytical method for the simultaneous analysis of current-use agricultural pesticides in surface waters is reported. The method involves minimal sample manipulation and small sample collection volumes (for 1 mL and 5 mL injections) with online sample clean-up and analyte preconcentration on a hydrophilic-lipophilic balance (HLB) column. To our knowledge, this online approach with the use of an HLB column has not yet been reported for multiresidue pesticide analysis in surface waters. Chromatographic separations of isomeric pesticides were achieved through the sequential coupling of C8 and polar endcapped C18 analytical columns. High resolution accurate mass (HRAM) quadrupole Orbitrap spectrometry was performed in full scan mode followed by data-dependent MS/MS fragmentation (FS-ddMS2) with concurrent electrospray ionization in both positive and negative modes. The method was validated for thirty-one (31) diverse current-use pesticides and demonstrated strong linearity (R2 > 0.9912) and precision (% RSD <8.4%) with low quantitation limits (average LOQ of 41 ng L-1). The majority of target analytes experienced minimal matrix effects (<±20%) in fortified environmental water samples. When applied to surface water samples, the method detected fourteen of the target analytes, including twelve herbicides, one insecticide, and one fungicide. This method offers a fast, simple, and reliable approach for the quantitative analysis of diverse current-use pesticides in surface water samples within hours of sample collection in the field. The robust nature of the method may allow for potential application to other types of water and the targeted or untargeted screening of other emerging contaminants.

Degradation of oxytetracycline and doxycycline by ozonation: Degradation pathways and toxicity assessment.

Tetracyclines are one of the antibiotics widely employed worldwide and frequently detected in surface waters because of incomplete removal from wastewater treatment. Various advanced oxidation processes have been investigated for tetracyclines degradation and their transformation products (TPs) have recently gained more attention. Studies on ozonation are however seldom for the degradation of oxytetracycline (OTC) and doxycycline (DTC). In the present study, a lower O3 inlet gas concentration (4.67 ± 0.13 mg/L), supplied at a flow rate of 0.27 L/min, was shown to be more effective at removing OTC than the same dose of ozone applied at higher inlet gas concentration (up to 6.29 mg/L) over a shorter time at the same flow rate. The use of pCBA and t-BuOH indicated that ozone plays a more important role in the degradation of OTC than HO•. The DTC degradation was less efficient than for OTC, with 99 % removal requiring twice the amount of ozone. OTC had almost no inhibition of Vibrio fischeri, however, the inhibition ratio was increased to 37 % (5-min) and 46 % (15-min) within 1 min of ozonation. Contrastly, DTC had toxic effects on V. fischeri (inhibition rate5min of 84 %) and sustained toxicity in samples treated for up to 40-min. The observed toxicities after treatment could be explained by the identified TPs (26 TPs for OTC and 23 for DTC, some identified for the first time) and their quantitative structure-activity relationship analysis data. Several TPs showed toxic or extremely toxic predicted effects on fish, daphnid, and green algae, corresponding with the V. fischeri inhibition results. Among the possible degradation pathways, aromatic ring hydroxylation and ring-opening pathways could lead to the formation of TPs less harmful to the environment.

Application of photocatalytic ozonation with a WO3/TiO2 catalyst for PFAS removal under UVA/visible light.

This research evaluates photocatalytic ozonation for removing 5 PFAS (PFOA/PFHxS/PFBS/6:2 FTS/GenX) from water using a WO3/TiO2 catalyst under UVA-visible radiation. Four catalysts of varying WO3 content (0/1/3/5 wt%) were synthesized by sol-gel and characterized by XRD, TEM, STEM-EDS, HAADF-STEM, adsorption/desorption N2 isotherms, and DRS-UV-vis. 5 wt% WO3/TiO2 was the optimal composition based on physicochemical properties and photocatalytic activity tests with methylene blue. PFAS degradation showed that photocatalytic ozonation inefficiently degraded PFAS with WO3/TiO2 under UVA-visible light after 4 h (ΣPFAS removal 16 %, [range 4 %-26 %]). Photocatalysis had comparable removal to photocatalytic ozonation, photolysis and ozone photolysis showed lower removal, and ozonation had no effect. Microtox analysis showed the initial acute toxicity was no longer detectable after photocatalysis and photocatalytic ozonation treatment. Low PFAS removals under tested conditions require that future work evaluate different catalysts or treatment conditions, while disparities between tested PFAS removals demonstrate the need to evaluate multiple compounds. ENVIRONMENTAL IMPLICATION: The research presented in this manuscript involves the preparation and characterization of WO3/TiO2 catalysts used, for the first time, to remove multiple PFAS in water via photocatalytic ozonation. This manuscript supports the development of a catalytic process for the elimination of hard to degrade environmental pollutants, provides new knowledge on aspects of photocatalytic processes, and provides insights on environmental pollution abatement.

Targeted screening of 11 bisphenols and 7 plasticizers in food composites from Canada and South Africa.

A sensitive method based on ultrasound-assisted liquid extraction coupled with liquid chromatography was applied to screen 18 plastic-related contaminants in 168 food composites (namely fish fillets, chicken breast, canned tuna, leafy vegetables, bread and butter) collected in Montreal (Canada), Pretoria and Vhembe (South Africa). Bisphenol A (BPA), bisphenol S (BPS) and seven plasticizers (di-n-butyl phthalate (DBP), diethyl phthalate (DEP), (2-ethylhexyl) phthalate (DEHP), di-(2-ethylhexyl) adipate (DEHA), di-isononyl phthalate (DINP), di-(isononyl)-cyclohexane-1,2-dicarboxylate (DINCH)) were detected in different foods from both countries. DBP and DEP were the most frequently detected contaminants in food collected in Montreal (75% for both) and DINP was the most frequently detected contaminant in food from South Africa (67%). DEHA concentration in packaged fish were significantly higher than the values for non-packaged fish (p < 0.01) suggesting that the packaging film can be one source of DEHA in fish.

Passive sampling and in vitro assays to monitor antiandrogens in a river affected by wastewater discharge.

Pharmaceuticals and personal care products, antibiotics, estrogens, and antiandrogens are found widely in aquatic environments. Monitoring studies by sampling surface water and effluents of wastewater treatment plants (WWTPs) have been conducted recently to monitor antiandrogens, which, along with estrogens, cause endocrine disruption. However, few studies have investigated antiandrogenic activity (AA) combined with a chemical analyses of emerging antiandrogens. Therefore, we analyzed the presence and persistence of 12 types of antiandrogens, atrazine, and carbamazepine using grab sampling and polar organic chemical integrative sampler (POCIS) along a river affected by WWTP discharges. Water and sediment samples were collected from the WWTP effluent (WW), as well as upstream (US) and downstream (DS) of the WWTP. We detected only tebuconazole, triclosan, propiconazole, and fluconazole during the two sampling campaigns in 2016 and 2017. Grab sampling of the site WW detected tebuconazole (7-77 ng/L), propiconazole (5-47 ng/L), and fluconazole (6-45 ng/L). However, the concentrations in the river water were below the detection limits. Nevertheless, fluconazole and triclosan were detected by POCIS in the site WW (45.7 and 26.8 ng/L, respectively) and all river samples ranges of 0.3-9.3 and 2.4-3.7, respectively. This detection was attributed to the limit of quantification of POCIS being lower than that of grab sampling. Nilutamide and triclosan were detected in the river sediment, suggesting that their concentrations in the water column were at least partly attenuated through sediment sorption. We also observed AA by analyzing POCIS extracts with the yeast androgen screen assay. The highest AA was found in the site WW and it was still observable several kilometers downstream of the point of discharge despite decreasing. Therefore, the WWTP effluent was most likely contributor to the persistent AA in the river.

Chronic Exposure to Two Gestagens Differentially Alters Morphology and Gene Expression in Silurana tropicalis.

Gestagens are active ingredients in human and veterinary drugs with progestogenic activity. Two gestagens-progesterone (P4), and the synthetic P4 analogue, melengestrol acetate (MGA)-are approved for use in beef cattle agriculture in North America. Both P4 and MGA have been measured in surface water receiving runoff from animal agricultural operations. This project aimed to assess the morphometric and molecular consequences of chronic exposures to P4, MGA, and their mixture during Western clawed frog metamorphosis. Chronic exposure (from embryo to metamorphosis) to MGA (1.7 µg/L) or P4 + MGA (0.22 µg/L P4 + 1.5 µg/L MGA) caused a considerable dysregulation of metamorphic timing, as evidenced by an inhibition of growth, narrower head, and lack of forelimb emergence in all animals. Molecular analysis revealed that chronic exposure to the mixture induced an additive upregulation of neurosteroid-related (GABAA receptor subunit α6 (gabra6) and steroid 5-alpha reductase 1 (srd5α1) gene expression in brain tissue. Chronic P4 exposure (0.26 µg/L P4) induced a significant upregulation of the expression hypothalamic-pituitary-gonadal (HPG)-related genes (ipgr, erα) in the gonadal mesonephros complex (GMC). Our data suggest that exposure to P4, MGA, and their mixture induces multiple endocrine responses and adverse effects in larval Western clawed frogs. This study helps to better our understanding of the consequences of chronic gestagen exposure and suggests that the implications and risk of high gestagen use in beef cattle feeding operations may extend to the aquatic environment.

Opioids, stimulants, and depressant drugs in fifteen Mexican Cities: A wastewater-based epidemiological study.

BACKGROUND: Monitoring drug use in México is a challenge due to emerging drugs and rapid changes in consumption patterns. The temporal and geographical patterns of cocaine, methamphetamine, amphetamine, MDMA, cannabis, heroin, ketamine, and fentanyl were examined in Mexican cities using wastewater-based epidemiology (WBE). METHODS: 105 daily composite wastewater samples were collected from sewage treatment plants in fifteen Mexican cities. We quantified drug residues using liquid chromatography-high-resolution mass spectrometry, and estimated drug use by back-calculation of drug loads. RESULTS: We identified ten drug target residues in at least one sample across cities. Drugs with the highest median levels were cannabis, methamphetamine, and cocaine. The median range of cannabis for one week was between 147 and 20,364 mg/day/1000inhab across cities, whereas methamphetamine ranged between 5 and 3,628 mg/day/1000inhab. Cocaine was found in levels between 2 and 370 mg/day/1000inhab. The highest levels of methamphetamine and amphetamine were observed in the US border cities of Tijuana and San Luis Río Colorado. The presence of heroin, MDMA, ketamine, and fentanyl was stronger during weekends, while cannabis, cocaine, and amphetamine were found throughout the week. CONCLUSION: This study provides the first report of fentanyl, norfentanyl, and ketamine in wastewater in Mexico. The results indicate an increased presence of drugs on known drug traffic routes, demonstrating that WBE can help identify areas of high drug use and assist governments in developing policies to reduce drug use and harm in the communities.

Impact of Suspended Solids on the Use of LuminoTox to Detect Toxicity of Micropollutants.

There is an increasing need for tools to monitor toxicity of contaminants of emerging concern (CECs) in wastewater. The purpose of this work was to assess interferences in the presence of total solids (TS) and total suspended solids (TSS) in the LuminoTox at concentrations typical of those found in municipal secondary effluent (SE) and to evaluate a simple sample enrichment method for increased CEC sensitivity. 4 or 10 µg/L atrazine in different TS concentrations and in corresponding filtrates (TSS removed) exhibited equivalent toxicities. Because the only difference between these two fractions is the TSS, this result demonstrates that, generally, this fraction does not induce toxicity nor interfere with the bioassay. At constant medium-low TS, the LuminoTox was able to detect the presence of 4 µg/L of atrazine but could not distinguish the change in atrazine concentration between 4 and 6 µg/L. No inhibition was observed in the presence of a mix of 14 CECs each at 0.23 µg/L. However, upon sample enrichment by lyophilization (50×), an inhibition of 81 ± 3% was observed. The enriched SE alone (not spiked with CECs) led to an inhibition of 49 ± 1%, indicating the detection of the CEC contribution to toxicity after sample preconcentration. The LuminoTox is a promising tool for monitoring SE; however, if the intent is to detect CECs, enrichment method optimization is required.

Sensitivity of the LuminoTox tool to monitor contaminants of emerging concern in municipal secondary wastewater effluent.

Contaminants of emerging concern (CECs) are generally poorly removed during conventional wastewater treatment. There is a need for rapid, sensitive and inexpensive methods to monitor the quality of treated wastewater effluent. The purpose of this study was to assess the applicability of the LuminoTox as a tool to monitor municipal secondary effluent (SE) and to determine its sensitivity to the presence of CECs. The effect of exposure method on a 14 CECs mix was explored; 20min in the dark or 30min under light were both recommended as they were sensitive to the detection of CECs in wastewater while providing a short run time. Stabilized aqueous photosynthetic systems (SAPS) detected the 14 CECs mix in the wastewater matrices when they were present at a concentration in the 6µg/L to 50µg/L range. Interference on the biosensors were examined in a range of wastewater characteristics commonly observed in SE and, for most cases, biosensors were not inhibited which suggests that, in most cases, wastewater characteristics would not cause toxic interferences. SAPS detected CECs in SE with different modes of action with the degree of sensitivity of individual CECs developed from experimental and literature values as follows: inhibitors of the plastoquinone binding site within photosystem II>direct or indirect inhibitors of photosynthesis acting on binding sites other than that of the QB. SAPS were assessed for their ability to detect residual CECs in SE without sample preparation, however, the effluent examined exhibited minimal inhibition for SAPS II (7±1%) and no inhibition for SAPS I. These results highlight the need for the development of a sample pre-concentration method to increase the biosensor sensitivity towards native CECs. This would allow the LuminoTox to be an effective tool for monitoring wastewater quality with the intent of residual CECs detection.

A beta cell ATGL-lipolysis/adipose tissue axis controls energy homeostasis and body weight via insulin secretion in mice.

AIMS/HYPOTHESIS: To directly assess the role of beta cell lipolysis in insulin secretion and whole-body energy homeostasis, inducible beta cell-specific adipose triglyceride lipase (ATGL)-deficient (B-Atgl-KO) mice were studied under normal diet (ND) and high-fat diet (HFD) conditions. METHODS: Atgl flox/flox mice were cross-bred with Mip-Cre-ERT mice to generate Mip-Cre-ERT/+;Atgl flox/flox mice. At 8 weeks of age, these mice were injected with tamoxifen to induce deletion of beta cell-specific Atgl (also known as Pnpla2), and the mice were fed an ND or HFD. RESULTS: ND-fed male B-Atgl-KO mice showed decreased insulinaemia and glucose-induced insulin secretion (GSIS) in vivo. Changes in GSIS correlated with the islet content of long-chain saturated monoacylglycerol (MAG) species that have been proposed to be metabolic coupling factors for insulin secretion. Exogenous MAGs restored GSIS in B-Atgl-KO islets. B-Atgl-KO male mice fed an HFD showed reduced insulinaemia, glycaemia in the fasted and fed states and after glucose challenge, as well as enhanced insulin sensitivity. Moreover, decreased insulinaemia in B-Atgl-KO mice was associated with increased energy expenditure, and lipid metabolism in brown (BAT) and white (WAT) adipose tissues, leading to reduced fat mass and body weight. CONCLUSIONS/INTERPRETATION: ATGL in beta cells regulates insulin secretion via the production of signalling MAGs. Decreased insulinaemia due to lowered GSIS protects B-Atgl-KO mice from diet-induced obesity, improves insulin sensitivity, increases lipid mobilisation from WAT and causes BAT activation. The results support the concept that fuel excess can drive obesity and diabetes via hyperinsulinaemia, and that an islet beta cell ATGL-lipolysis/adipose tissue axis controls energy homeostasis and body weight via insulin secretion.

A role for cytosolic isocitrate dehydrogenase as a negative regulator of glucose signaling for insulin secretion in pancreatic ß-cells.

Cytosolic NADPH may act as one of the signals that couple glucose metabolism to insulin secretion in the pancreatic ß-cell. NADPH levels in the cytoplasm are largely controlled by the cytosolic isoforms of malic enzyme and isocitrate dehydrogenase (IDHc). Some studies have provided evidence for a role of malic enzyme in glucose-induced insulin secretion (GIIS) via pyruvate cycling, but the role of IDHc in ß-cell signaling is unsettled. IDHc is an established component of the isocitrate/α-ketoglutarate shuttle that transfers reducing equivalents (NADPH) from the mitochondrion to the cytosol. This shuttle is energy consuming since it is coupled to nicotinamide nucleotide transhydrogenase that uses the mitochondrial proton gradient to produce mitochondrial NADPH and NAD(+) from NADP(+) and NADH. To determine whether flux through IDHc is positively or negatively linked to GIIS, we performed RNAi knockdown experiments in ß-cells. Reduced IDHc expression in INS 832/13 cells and isolated rat islet ß-cells resulted in enhanced GIIS. This effect was mediated at least in part via the KATP-independent amplification arm of GIIS. IDHc knockdown in INS 832/13 cells did not alter glucose oxidation but it reduced fatty acid oxidation and increased lipogenesis from glucose. Metabolome profiling in INS 832/13 cells showed that IDHc knockdown increased isocitrate and NADP(+) levels. It also increased the cellular contents of several metabolites linked to GIIS, in particular some Krebs cycle intermediates, acetyl-CoA, glutamate, cAMP and ATP. The results identify IDHc as a component of the emerging pathways that negatively regulate GIIS.

Beta-cell failure in diet-induced obese mice stratified according to body weight gain: secretory dysfunction and altered islet lipid metabolism without steatosis or reduced beta-cell mass.

OBJECTIVE: C57Bl/6 mice develop obesity and mild hyperglycemia when fed a high-fat diet (HFD). Although diet-induced obesity (DIO) is a widely studied model of type 2 diabetes, little is known about beta-cell failure in these mice. RESEARCH DESIGN AND METHODS: DIO mice were separated in two groups according to body weight gain: low- and high-HFD responders (LDR and HDR). We examined whether mild hyperglycemia in HDR mice is due to reduced beta-cell mass or function and studied islet metabolism and signaling. RESULTS: HDR mice were more obese, hyperinsulinemic, insulin resistant, and hyperglycemic and showed a more altered plasma lipid profile than LDR. LDR mice largely compensated insulin resistance, whereas HDR showed perturbed glucose homeostasis. Neither LDR nor HDR mice showed reduced beta-cell mass, altered islet glucose metabolism, and triglyceride deposition. Insulin secretion in response to glucose, KCl, and arginine was impaired in LDR and almost abolished in HDR islets. Palmitate partially restored glucose- and KCl-stimulated secretion. The glucose-induced rise in ATP was reduced in both DIO groups, and the glucose-induced rise in Ca(2+) was reduced in HDR islets relatively to LDR. Glucose-stimulated lipolysis was decreased in LDR and HDR islets, whereas fat oxidation was increased in HDR islets only. Fatty acid esterification processes were markedly diminished, and free cholesterol accumulated in HDR islets. CONCLUSIONS: beta-Cell failure in HDR mice is not due to reduced beta-cell mass and glucose metabolism or steatosis but to a secretory dysfunction that is possibly due to altered ATP/Ca(2+) and lipid signaling, as well as free cholesterol deposition.

Adipose triglyceride lipase is implicated in fuel- and non-fuel-stimulated insulin secretion.

Reduced lipolysis in hormone-sensitive lipase-deficient mice is associated with impaired glucose-stimulated insulin secretion (GSIS), suggesting that endogenous beta-cell lipid stores provide signaling molecules for insulin release. Measurements of lipolysis and triglyceride (TG) lipase activity in islets from HSL(-/-) mice indicated the presence of other TG lipase(s) in the beta-cell. Using real time-quantitative PCR, adipose triglyceride lipase (ATGL) was found to be the most abundant TG lipase in rat islets and INS832/13 cells. To assess its role in insulin secretion, ATGL expression was decreased in INS832/13 cells (ATGL-knockdown (KD)) by small hairpin RNA. ATGL-KD increased the esterification of free fatty acid (FFA) into TG. ATGL-KD cells showed decreased glucose- or Gln + Leu-induced insulin release, as well as reduced response to KCl or palmitate at high, but not low, glucose. The K(ATP)-independent/amplification pathway of GSIS was considerably reduced in ATGL-KD cells. ATGL(-/-) mice were hypoinsulinemic and hypoglycemic and showed decreased plasma TG and FFAs. A hyperglycemic clamp revealed increased insulin sensitivity and decreased GSIS and arginine-induced insulin secretion in ATGL(-/-) mice. Accordingly, isolated islets from ATGL(-/-) mice showed reduced insulin secretion in response to glucose, glucose + palmitate, and KCl. Islet TG content and FFA esterification into TG were increased by 2-fold in ATGL(-/-) islets, but glucose usage and oxidation were unaltered. The results demonstrate the importance of ATGL and intracellular lipid signaling for fuel- and non-fuel-induced insulin secretion.

Human papillomavirus type 16 variants in cervical intraepithelial neoplasia and invasive carcinoma in San Luis Potosí City, Mexico.

BACKGROUND: In San Luis Potosí City cervical infection by human papillomavirus type 16 (HPV16) associated to dysplastic lesions is more prevalent in younger women. In this work HPV16 subtypes and variants associated to low-grade intraepithelial lesions (LSIL), high-grade intraepithelial lesions (HSIL) and invasive cervical cancer (ICC) of 38 women residing in San Luis Potosí City were identified by comparing their E6 open reading frame sequences. RESULTS: Three European (E) variants (E-P, n = 27; E-T350G, n = 7; E-C188G, n = 2) and one AA-a variant (n = 2) were identified among the 38 HPV16 sequences analyzed. E-P variant sequences contained 23 single nucleotide changes, two of which (A334G, A404T) had not been described before and allowed the phylogenetic separation from the other variants. E-P A334G sequences were the most prevalent (22 cases, 57.9%), followed by the E-P Ref prototype (8 cases, 21.1%) and E-P A404T (1 case, 2.6%) sequences. The HSIL + ICC fraction was 0.21 for the E-P A334G variants and 0.00 for the E-P Ref variants. CONCLUSION: We conclude that in the women included in this study the HPV16 E subtype is 19 times more frequent than the AA subtype; that the circulating E variants are E-P (71.1%) > E-T350G (18.4%) > E-C188G (5.3%); that 71.0% of the E-P sequences carry the A334G single nucleotide change and appear to correspond to a HPV16 variant characteristic of San Luis Potosi City more oncogenic than the E-P Ref prototype.

Structure of L-xylulose-5-Phosphate 3-epimerase (UlaE) from the anaerobic L-ascorbate utilization pathway of Escherichia coli: identification of a novel phosphate binding motif within a TIM barrel fold.

Three catabolic enzymes, UlaD, UlaE, and UlaF, are involved in a pathway leading to fermentation of l-ascorbate under anaerobic conditions. UlaD catalyzes a beta-keto acid decarboxylation reaction to produce L-xylulose-5-phosphate, which undergoes successive epimerization reactions with UlaE (L-xylulose-5-phosphate 3-epimerase) and UlaF (L-ribulose-5-phosphate 4-epimerase), yielding D-xylulose-5-phosphate, an intermediate in the pentose phosphate pathway. We describe here crystallographic studies of UlaE from Escherichia coli O157:H7 that complete the structural characterization of this pathway. UlaE has a triosephosphate isomerase (TIM) barrel fold and forms dimers. The active site is located at the C-terminal ends of the parallel beta-strands. The enzyme binds Zn(2+), which is coordinated by Glu155, Asp185, His211, and Glu251. We identified a phosphate-binding site formed by residues from the beta1/alpha1 loop and alpha3' helix in the N-terminal region. This site differs from the well-characterized phosphate-binding motif found in several TIM barrel superfamilies that is located at strands beta7 and beta8. The intrinsic flexibility of the active site region is reflected by two different conformations of loops forming part of the substrate-binding site. Based on computational docking of the L-xylulose 5-phosphate substrate to UlaE and structural similarities of the active site of this enzyme to the active sites of other epimerases, a metal-dependent epimerization mechanism for UlaE is proposed, and Glu155 and Glu251 are implicated as catalytic residues. Mutation and activity measurements for structurally equivalent residues in related epimerases supported this mechanistic proposal.

[Comparative study of clinical and pathological features of breast cancer in women with 40 years old and younger vs 70 years old and older]. / Comparación de las características de pacientes de 40 o menos y 70 años o más de edad con carcinoma mamario.

BACKGROUND: Invasive breast cancer is the most common neoplasia in women attended at IMSS health system since 2004. OBJECTIVE: To compare clinical and radiological characteristics on initial appraisal, as well as surgical treatment, pathological features and adjuvant treatment in women with primary breast cancer of 40 years old and younger vs 70 years old and older. MATERIAL AND METHOD: Clinical, radiological and pathological data of 150 patients with breast cancer treated at Hospital de ginecoobstetricia Luis Castelazo Ayala, from January 2003 to June 2006 were collected, and after divided in two groups: 1) patients with 40 years old and younger (n = 50), and 2) patients with 70 years old and older (n = 100). RESULTS: Tumoral size and radiological characteristics were similar in both groups. Group 1 and group 2 had 22 and 13%, respectively, of family history of breast cancer. Fine needle biopsy has positive predictive value of 50% for group 1, and 36% for group 2. Conservative surgery was less common at group 2. Most frequent histological type in both groups was infiltrating ductal carcinoma, followed by infiltrating lobular carcinoma, most common in older women (19 vs 12%), and we found more well differentiated ductal carcinomas in the group of 70 years old and older (12 vs 4%). Seventy-six percent of group 1 and 75% of group 2 were classified as early stage breast cancer (stages I and II). Cytotoxic therapy was offered mostly to group 1, 92 vs 35%. Radiotherapy (80 vs 59%), and hormonal therapy was given only to 56% of group 1 vs 80% of group 2. CONCLUSIONS: Clinical and staging features were similar in both groups. Family history was more influential to group 1. Fine needle biopsy has a low positive predictive value for diagnostic. Well-differentiated carcinomas were higher in patients of group 2, and group 1 had more high-grade carcinomas. There was a trend to perform more conservative surgery at group 1, as well as they underwent more adjuvant chemotherapy and radiotherapy. Use of hormonal therapy was more common at group 2.

[Identification of surgical margins by intraoperative mammography of quadrantectomys specimens for breast cancer and histopathological comparison]. / Identificación de los márgenes quirúrgicos mediante mastografía transoperatoria de cuadrantectomías por cáncer de mama y comparación histopatológica.

BACKGROUND: Wide surgical margins are prognostic indicators to prevent recurrences after conservative surgery in breast cancer; type of surgery and histopathological analysis are key factors too. OBJECTIVES: To evaluate tumoral size and surgical margins of quadrantectomy specimens utilizing mammography and histopathology, and decide if mammography of quadrantectomy specimens are useful for close margins prediction. MATERIALS AND METHODS: Prospective, observational and descriptive study based on the findings of specimen projections of two mammography quadrantectomies, and histopathological data. Ten patients with breast cancer were evaluated from May to November 2006. Surgical margins of quadrantectomys were marked with radiopaque material. RESULTS: Tumoral size was similar in mammography and histopathological analysis of quadrantectomys, however there was a tendency to report a larger size in mammography. With mammography only one case was reported as close superficial margin, the rest of patients has adequate margins (1 cm or higer). Five cases were close by histopathology (3 in the deep margin, one superior and one more in the superior and inferior margins), and five had adequate margins. Four additional surgical procedures where practiced (3 re-excisions and one mastectomy), in one of them additional surgery was unnecessary. CONCLUSIONS: Mammography evaluation was useful to identify peripheral margins (superior, inferior medial and lateral) as well as tumoral size, but useless to identify close borders (deep and superficial areas). It is necessary to evaluate more cases to improve this technique and to establish a common language between specialists.