Endothermic physiology of extinct megatooth sharks.

The evolution of the extinct megatooth shark, Otodus megalodon, and its close phylogenetic relatives remains enigmatic. A central question persists regarding the thermophysiological origins of these large predatory sharks through geologic time, including whether O. megalodon was ectothermic or endothermic (including regional endothermy), and whether its thermophysiology could help to explain the iconic shark's gigantism and eventual demise during the Pliocene. To address these uncertainties, we present unique geochemical evidence for thermoregulation in O. megalodon from both clumped isotope paleothermometry and phosphate oxygen isotopes. Our results show that O. megalodon had an overall warmer body temperature compared with its ambient environment and other coexisting shark species, providing quantitative and experimental support for recent biophysical modeling studies that suggest endothermy was one of the key drivers for gigantism in O. megalodon and other lamniform sharks. The gigantic body size with high metabolic costs of having high body temperatures may have contributed to the vulnerability of Otodus species to extinction when compared to other sympatric sharks that survived the Pliocene epoch.

Enhanced Surveillance for Coccidioidomycosis, 14 US States, 2016.

Although coccidioidomycosis in Arizona and California has been well-characterized, much remains unknown about its epidemiology in states where it is not highly endemic. We conducted enhanced surveillance in 14 such states in 2016 by identifying cases according to the Council of State and Territorial Epidemiologists case definition and interviewing patients about their demographic characteristics, clinical features, and exposures. Among 186 patients, median time from seeking healthcare to diagnosis was 38 days (range 1-1,654 days); 70% had another condition diagnosed before coccidioidomycosis testing occurred (of whom 83% were prescribed antibacterial medications); 43% were hospitalized; and 29% had culture-positive coccidioidomycosis. Most (83%) patients from nonendemic states had traveled to a coccidioidomycosis-endemic area. Coccidioidomycosis can cause severe disease in residents of non-highly endemic states, a finding consistent with previous studies in Arizona, and less severe cases likely go undiagnosed or unreported. Improved coccidioidomycosis awareness in non-highly endemic areas is needed.

Infection control response to an outbreak of OXA-23 carbapenemase-producing carbapenem-resistant Acinetobacter baumannii in a skilled nursing facility in Utah.

BACKGROUND: Antibiotic-resistant Acinetobacter species are a growing public health threat, yet are not nationally notifiable, and most states do not mandate reporting. Additionally, there are no standardized methods to detect Acinetobacter species colonization. METHODS: An outbreak of carbapenem-resistant Acinetobacter baumannii (CRAB) was identified at a Utah ventilator unit in a skilled nursing facility. An investigation was conducted to identify transmission modes in order to control spread of CRAB. Culture-based methods were used to identify patient colonization and environmental contamination in the facility. RESULTS: Of the 47 patients screened, OXA-23-producing CRAB were detected in 10 patients (21%), with 7 patients (15%) having been transferred from out-of-state facilities. Of patients who screened positive, 60% did not exhibit any signs or symptoms of active infection by chart review. A total of 38 environmental samples were collected and CRAB was recovered from 37% of those samples. Whole genome sequencing analyses of patient and environmental isolates suggested repeated CRAB introduction into the facility and highlighted the role of shared equipment in transmission. CONCLUSIONS: The investigation demonstrated this ventilated skilled nursing facility was an important reservoir for CRAB in the community and highlights the need for improved surveillance, strengthened infection control and inter-facility communication within and across states.

Socioeconomic Determinants of Cipro-floxacin-Resistant Shigella Infections in Bangladeshi Children.

BACKGROUND: Shigella species (spp.) are a leading cause of moderate to severe diarrhea in children worldwide. The recent emergence of quinolone-resistant Shigella spp. gives cause for concern, and South Asia has been identified as a reservoir for global spread. The influence of socioeconomic status on antimicrobial resistance in developing countries, such as those in South Asia, remains unknown. METHODS: We used data collected from 2009 to 2014 from a hospital specializing in the treatment of diarrhea in Dhaka, Bangladesh, to determine the relationship between Ciprofloxacin-resistant Shigella spp. isolates and measures of socioeconomic status in Bangladeshi children less than 5 years of age. RESULTS: We found 2.7% (230/8,672) of children who presented with diarrhea had Shigella spp. isolated from their stool, and 50% (115/230) had resistance to Ciprofloxacin. Using multivariable logistic regression analysis, we found that children from families where the father's income was in the highest quintile had significantly higher odds of having Ciprofloxacin-resistant Shigella spp. compared to children in the lowest quintile (OR = 6.1, CI 1.9-19). Factors protective against the development of resistance included access to improved sanitation (OR = 0.27, CI 0.11-0.7), and improved water sources (OR = 0.48, CI 0.25-0.92). We did not find a relationship between Ciprofloxacin resistance and other proxies for socioeconomic status, including the presence of animals in the home, nutritional status, paternal education level, and the number of family members in the home. CONCLUSIONS: Although the associations between wealth and antimicrobial resistance are not fully understood, possible explanations include increased access and use of antibiotics, greater access to healthcare facilities and thus resistant pathogens, or greater consumption of commercially produced foods prepared with antibiotics.

Silicone rubber selection for passive sampling of pesticides in water.

Silicone rubber can extract organic compounds with a broad range of polarities (logKow>2-3) from aqueous samples. Such compounds include substances of major concern in the protection of aquatic ecosystems and human health, e.g. pesticides. Silicone rubbers (SRs) with various characteristics have been successfully used in sorptive methods for water sample extraction in the laboratory (SPME, SBSE), and for passive sampling in aquatic environments. However, only few studies have evaluated variability in organic compound sorption due to the origin of SRs, particularly for pesticides. The aim of this study was to select an SR for the extraction of pesticides from water samples by passive sampling. To this end we measured the impact of seven SR formulations on sorption capacity, defined by the partition coefficient (Ksw). Kinetic experiments and sorption isotherms were performed to determine extraction recovery as a selection criterion for SRs, and pesticide partition coefficients. Very large differences in affinity for pesticides were found between two kinds of SRs: "Polymerized SR kits" and "Manufactured SRs". One SR was chosen among the "Manufactured SRs", and the Ksw values of 21 pesticides were determined, filling a gap in the literature (1.50

Immune Responses to an Oral Cholera Vaccine in Internally Displaced Persons in South Sudan.

Despite recent large-scale cholera outbreaks, little is known about the immunogenicity of oral cholera vaccines (OCV) in African populations, particularly among those at highest cholera risk. During a 2015 preemptive OCV campaign among internally displaced persons in South Sudan, a year after a large cholera outbreak, we enrolled 37 young children (1-5 years old), 67 older children (6-17 years old) and 101 adults (≥18 years old), who received two doses of OCV (Shanchol) spaced approximately 3 weeks apart. Cholera-specific antibody responses were determined at days 0, 21 and 35 post-immunization. High baseline vibriocidal titers (>80) were observed in 21% of the participants, suggesting recent cholera exposure or vaccination. Among those with titers ≤80, 90% young children, 73% older children and 72% adults seroconverted (≥4 fold titer rise) after the 1st OCV dose; with no additional seroconversion after the 2nd dose. Post-vaccination immunological endpoints did not differ across age groups. Our results indicate Shanchol was immunogenic in this vulnerable population and that a single dose alone may be sufficient to achieve similar short-term immunological responses to the currently licensed two-dose regimen. While we found no evidence of differential response by age, further immunologic and epidemiologic studies are needed.

Development of insulin release by fetal rat pancreas in vitro: effects of glucose, amino acids, and theophylline.

The dynamics of insulin release by pieces of fetal rat pancreas from 17.5 to 21.5 days of gestation was measured in an in vitro perifusion system. Interactions between glucose, theophylline, and a mixture of 12 amino acids at physiologic concentration (mix. A.A.) were studied. On day 17.5, 13.9 mM glucose induced only a small (10 min) early phase of insulin release. The late phase of insulin secretion appeared on day 18.5 and gradually increased as the gestation proceeded. The mix. A.A. (9 mM) or theophylline (5 mM) potentiated the two phases of insulin release induced by 13.9 mM glucose from days 18.5 to 21.5 of gestation. On day 21.5, the combination of theophylline and mix. A.A. at 2.2 mM glucose stimulated insulin release by fetal pancreas. The dose-dependent curves of the early phase of insulin release, due to glucose or glucose and mix. A.A. (9 mM), showed half maximal responses in the term fetal pancreas at glucose concentrations of 7.2 and 4 mM, respectively. The values were 7.9 and 5.9 mM for the late phase. The results indicate that the mechanisms controlling biphasic insulin release develop during the late fetal life in the rat. Transition from the fetal to adult type of insulin secretion more likely parallels quantitative, rather than qualitative, changes within the B cells.

In-line coupling of an aptamer based miniaturized monolithic affinity preconcentration unit with capillary electrophoresis and Laser Induced Fluorescence detection.

A composite 30-cm capillary was prepared. The head of the capillary was a 1.5-cm original and miniaturized aptamer-based monolithic affinity support that was in-line coupled to the end of the capillary used for capillary electrophoresis (CE) with laser induced fluorescence (LIF) detection. The device was used for the preconcentration, separation and quantification of ochratoxin A (OTA) as a test solute. The 1.5-cm preconcentration unit consists of a fritless affinity monolithic bonded with 5'-SH-modified oligonucleotide aptamers. A vinyl spacer was used for thiol-ene photoclick chemistry with a 5min irradiation at 365nm. Photografting allowed to confine the binding reaction to the desired silica monolithic segment, upstream the empty section of the CE capillary using an UV mask. The photografting procedure was optimized preparing 10-cm capillary monoliths for nano-LC. The retention factors of cationic solutes in ion-exchange nano-LC allowed to follow the aptamer binding on the monolith. The reproducibility of the photografting process was satisfactory with inter-capillary variation lower than 10%. The aptamer bonding density can be increased by successive graftings of 100µM aptamer concentration solution (5pmol/cm/grafting). The optimal conditions to successfully perform the in-line coupling (preconcentration, elution and separation of OTA) with the composite capillary were adjusted depending on individual requirements of each step but also insuring compatibility. Under optimized conditions, OTA was successfully preconcentrated and quantified down to 0.1pg (percolation of 2.65µL of a 40ng/L OTA solution). A quantitative recovery of OTA (93±2%) was achieved in a single elution of 30pg percolated OTA amount. The reproducibility of the overall process was satisfactory with a relative standard deviation lower than 10% with negligible non-specific adsorption. This device was applied for the preconcentration and analysis of OTA in beer and wine at the ppb level within a total analysis time of 30min.

Antigen induces leucopenia in non-immunised guinea-pigs injected with platelets from actively sensitized animals.

1. Ovalbumin administration to animals injected with 0.5-5 x 10(6) washed platelets microliter-1 from actively sensitized animals induced a marked decrease (maximum of around 50% at 60 min) in the number of circulating leucocytes, whereas platelet counts were unaffected. The intensity of the decrease in leucocyte counts was dependent upon the concentration of the injected platelets. 2. No drop in leucocyte counts was measured upon antigen challenge of guinea-pigs injected with platelets from non-sensitized animals. 3. This phenomenon was unaffected by pretreatment of the recipient animals with a platelet-activating factor (PAF) antagonist WEB 2086 (3 mg kg-1 i.v.) but was markedly reduced (around 50% inhibition) by the anti-allergic drug nedocromil sodium (100 mg kg-1 i.v.). By contrast, indomethacin (5 mg kg-1 i.v.) caused a significant (P less than 0.01) enhancement of the antigen-induced leucopenia, whereas the mixed cyclooxygenase and lipoxygenase inhibitor, BW 755C (10 mg kg-1 i.v.) suppressed the drop in leucocyte counts evoked by ovalbumin administration. 4. These results indicate that platelets from actively sensitized guinea-pigs transferred to normal animals still responds to the specific antigen with the activation of circulating leucocytes. This phenomenon appears to be independent of the production of PAF and of cyclo-oxygenase metabolites. By contrast, the production of the metabolites of the lipoxygenase pathway by platelets could account for the marked leucopenia observed following the immunological stimulation.

Blockade by methylation inhibitors of the anaphylactic response of guinea-pig lung strips.

1. The combination of two methylation inhibitors 3-deazaadenosine (10(-4) or 4 x 10(-4) M) plus L-homocysteine (2 x 10(-4) M) caused a time-dependent inhibition of antigen-induced contraction, formation of thromboxane B2 (TxB2) and release of histamine from lung parenchyma strips taken from guinea-pigs actively sensitized with ovalbumin (OA). 2. The methylation inhibitors also prevented the lung strip contractions induced by the mediators platelet-activating factor (Paf-acether, 10(-6) M), leukotriene D4 (LTD4, 10(-8) and 3 x 10(-8) M), and in part to arachidonic acid (10(-6) and 10(-5) M), under conditions where the contractions to histamine (10(-6)-10(-4) M) were virtually unaffected. 3. TxB2 formation induced by these mediators or by OA was more affected by the methylation inhibitors than the lung strip contractions, indicating that prostaglandin formation is more sensitive to these inhibitors than the myotropic activity. In contrast, the suppressive effect of the methylation inhibitors on histamine secretion by parenchyma lung strips induced by OA followed the inhibition of the contraction. 4. These results show that inhibitors of methyltransferases interfere with the myotropic responses and with the release of mediators by actively sensitized guinea-pig lung strips stimulated with antigen, and suggest a major role for a methylation process in mediating the contraction of and mediator release by the lung parenchyma.

Reduction by arachidonic acid of prostaglandin I2-induced cyclic AMP formation. Involvement of prostaglandins E2 and F2 alpha.

Arachidonic acid reverses the increase in cyclic AMP levels of washed human platelets exposed to prostaglandin (PG)I2, under conditions where the PGH2 analogue U46619 is ineffective. This effect of arachidonic acid was inhibited by aspirin, a cyclooxygenase inhibitor, but not by the thromboxane (Tx) synthase inhibitor Ridogrel, which induces, by inhibiting the conversion of PGH2 into TxA2, an overproduction of PGE2, PGD2 and PGF2 alpha. Addition of PGE2 or PGF2 alpha, which share a receptor with PGI2, to washed human platelets also induced a decrease in cyclic AMP levels, but PGD2, which interacts with a different receptor, had no effect. Thus neither PGD2, PGG2, PGH2, TxA2 nor TxB2 formed from arachidonic acid via the cyclooxygenase pathway is involved in the decrease in cyclic AMP levels. These findings were confirmed using forskolin, a diterpene from the labdane family, which enhanced the formation of cyclic AMP synergistically with the PGs. Also, arachidonic acid, unlike U46619, is able to reverse the inhibition of platelet aggregation by PGI2 after a lag phase of about 4 min. Our data indicate that arachidonic acid decreased cyclic AMP levels through its cyclooxygenase metabolites PGE2 and PGF2 alpha probably interacting competitively with the receptor of PGI2. In addition, intracellular cyclic AMP levels and the degree of aggregation of platelets by arachidonic acid seem to be inversely correlated.

Pharmacological profile of 48740 R.P., a PAF-acether antagonist.

The pyrrolo-thiazole derivative 48740 R.P. inhibited the platelet-activating factor (PAF-acether)-induced aggregation of human and rabbit platelets and was poorly effective against ADP- and arachidonic acid-induced platelet aggregation. 48740 R.P. prevented the activation of guinea-pig alveolar macrophages by PAF-acether, and the PAF-acether-induced thromboxane B2 production from guinea-pig lungs. 48740 R.P. (3 mg/kg i.v.) antagonized selectively in anaesthetized guinea-pigs the bronchoconstriction due to PAF-acether without affecting that due to acetylcholine, histamine, serotonin, thromboxane A2 analogue U-46,619 and arachidonic acid. A higher dose of 48740 R.P. (10 mg/kg i.v.) was required to block the thrombocytopenia and the leucopenia induced by PAF-acether in the propranolol-treated guinea-pigs. 48740 R.P. (30 mg/kg i.v.) antagonized the PAF-acether effects when bronchoconstriction was induced by aerosolized PAF-acether. 48740 R.P. is a selective antagonist of PAF-acether under in vitro and in vivo conditions.

Interference of BN 52021 (ginkgolide B) with the bronchopulmonary effects of PAF-acether in the guinea-pig.

The interaction between the ginkgolide BN 52021 and the effects of PAF-acether on the bronchopulmonary system of the guinea-pig was studied. In pentobarbitone or ethyl carbamate-anaesthetized animals, BN 52021 (1 mg/kg i.v. or 10 mg/kg p.o.) inhibited bronchoconstriction, the hematocrit increase and the accompanying thrombopenia and leukopenia induced by PAF-acether (33-100 ng/kg) and failed to block the bronchoconstriction produced by collagen, arachidonic acid and the tripeptide formyl-Met-Leu-Phe (FMLP). BN 52021, 3 mg/kg, reduced the bronchoconstriction induced by aerosolized PAF-acether. BN 52021, 300 microM, also inhibited the superoxide production by PAF-acether-stimulated alveolar macrophages and failed to reduce the same effects when triggered by FMLP (0.01-1 microM). BN 52021 blocked the formation of thromboxane-triggered by PAF-acether (100 ng) injected into perfused lung, under conditions where the effects of arachidonic acid where not modified. Finally, pretreatment of parenchyma lung strips with BN 52021 (100 microM) partially inhibited the contraction induced by PAF-acether (0.1 microM) and suppressed the accompanying release of thromboxane. BN 52021 is a selective antagonist of the effects of PAF-acether on the bronchopulmonary system and on circulating blood cells of the guinea-pig.

Comparison between the antiaggregating effect of ticlopidine in whole blood, platelet-rich plasma and washed platelets of the rat.

Ticlopidine, an inhibitor of platelet activation enhances the antiaggregating effect of prostaglandins (PG) E1 and I2 when applied to rat whole blood or platelet-rich plasma. Aggregation by ADP was inhibited to a similar extent when evaluated on whole blood and on PRP of ticlopidine-treated rats showing that circulating PGs are probably not directly responsible for the antiaggregating effects of the drug. When platelets collected from ticlopidine-treated rats were separated from their plasma, they became largely refractory to ADP. PGE2 was equally effective in potentiating platelet aggregation of washed platelets of treated and untreated animals, but failed to fully restore the impaired responsiveness to ADP of washed platelets from ticlopidine-treated rats. Our results indicate that ticlopidine does not prevent platelet aggregation by enhancing the antiaggregating effect of circulating PGs, and that ticlopidine or a metabolite, interact directly with the rat platelet, reducing its responsiveness to ADP.

Convulxin, a potent platelet-aggregating protein from Crotalus durissus terrificus venom, specifically binds to platelets.

Convulxin, a very potent aggregating protein from rattlesnake venom, was purified by a new procedure and its heterodimeric structure alpha 3 beta 3 was confirmed. The polypeptide N-terminal sequences of convulxin subunits were determined by Edman degradation. They are very similar and appear homologous to botrocetin from Bothrops jararaca venom and to rattlesnake lectin from Crotalus atrox venom, both being classified among the C-type lectin family. The binding of 125I-labelled convulxin to blood platelets has also been analysed under equilibrium conditions. These studies indicated that convulxin binds to platelets with a high affinity (Kd = 30 pM) on a small number of binding sites (1000 binding sites per cell). The high-affinity binding of convulxin appears specific to platelets, since it is not observed on other cell types such as neutrophils and erythrocytes. Also, the high-affinity binding of convulxin to membranes platelet is not inhibited by alpha-thrombin, fibrinogen, collagen, laminin binding inhibitor, RGDS peptide, adenosine diphosphate, platelet-activating factor-acether, serotonin or epinephrine. This, together with the recent observation that platelet activation by convulxin is partially mediated by phospholipase C and involves other mechanisms as well, indicates that convulxin may interact with a specific platelet acceptor (receptor) protein which has yet to be characterized.

Control of electroosmotic flow in zirconia-coated capillaries.

The inner surface of a silica capillary has been modified using an anhydrous sol-gel method: zirconium propoxide reacted with silanol groups to give, after hydrolysis, a "zirconia-like" surface. The electroosmotic properties of zirconia-modified capillaries have been studied under various conditions: working parameters were nature and concentration of the electrolyte, ionic strength, pH and solvent composition. Using different ions such as sodium, potassium, chloride, nitrate or methanoate, a positive electroosmotic flow (cathodic flow) was observed in the pH range 5-11. But below pH 5, a negative electroosmotic flow (anodic flow) occurred, corresponding to a permanent positive surface charge of the capillary walls. The value of the electroosmotic flow (including the sign) can be easily controlled by adding multivalent ions in the electrolyte. Some of these modifications of surface charge can be made irreversible. The observed electroosmotic flow has been related to surface characteristics using the triple layer model. With the large set of working parameters, the optimisation of separations can be facilitated. An example of flow control is given for the separation of four antihistaminic compounds.

[Expression of cytokines and their receptors in left ventricular hypertrophy in TGR(mRen2)27 rats]. / Expression des cytokines et de leurs récepteurs dans le ventricule gauche hypertrophique du rat TGR(mRen2)27.

Variations in the expression of cytokines from the interleukin-6 (IL-6) family: ciliary neurotrophic factor (CNTF), leukaemia inhibitory factor (LIF), and cardiotrophin 1 (CT-1) were studied during cardiac remodelling leading to left ventricular hypertrophy (LVH) in TGR(mRen2)27 rats at the age of 8 and 20 weeks. The cytokines mRNA levels within the free wall of the left ventricle were measured by semi-quantitative RT-PCR standardised with 18S. They were compared between heterozygous rats for the mRen2 transgene (TG+/-) and control rats (TG-/-). No significant difference was observed between results obtained at 8 and 20 weeks of age. At 20 weeks of age, TGR(mRen2)27 rats showed higher levels of mRNA LIF and IL-6 respectively by 52 and 55% compared to the control rats [LIF TG+/-: 3.17 +/- 0.21, TG-/-: 2.09 +/- 0.03; p < 0.001; n = 5; and IL-6 TG+/-: 1.53 +/- 0.13; TG-/-: 0.99 +/- 0.17; p < 0.05; n = 5]. By contrast, no variation of mRNAs levels of CT-1 and gp 130 genes was observed between control and transgenic rats. Concerning the cytokine receptors, the levels of mRNA for IL-6R did not vary while those of receptor subunits LIFR and CNTFR were decreased respectively by 48 and 42% in transgenic rats vs controls [LIFR TG+/-: 0.48 +/- 0.01; TG-/-: 0.92 +/- 0.08 p < 0.001; n = 5; and CNTFR TG+/-: 1.07 +/- 0.08; TG-/-: 1.85 +/- 0.18; p < 0.01; n = 5]. Therefore, these results show a specific pattern of activation of the cytokines pathway in the LVH of the TGR(mRen2)27 rat.

Gas chromatography-mass spectroscopy optimization by computer simulation, application to the analysis of 93 volatile organic compounds in workplace ambient air.

GC-MS optimization method including both advantages from chromatographic separation and mass spectrometric detection was designed for a set of 93 volatile organic compounds. Only a few experiments were necessary to determine the thermodynamic retention parameters for all compounds on a RTX-VMS column. From these data, computer simulation was used in order to predict the retention times of the compounds in temperature programmed gas chromatography. Then, an automatic selection of ions from the NIST database was performed and compared to the optimum conditions (full separation of VOC). This simulation-selection procedure was used to screen a numerous set of GC and MS conditions in order to quickly design a GC-MS method whatever the set of compounds considered.

"Thiol-ene" photoclick chemistry as a rapid and localizable functionalization pathway for silica capillary monolithic columns.

Herein, we report the "ene-thiol" photografting of 1-octadecanethiol onto vinyl pre-functionalized silica monolith to prepare clicked reversed-phase silica monolithic columns with high permeability and performances. The experimental conditions (concentration of thiol in solution, irradiation duration) are optimized with respect to highest retention and methylene selectivity, i.e. to the highest surface coverage of the monolith. It is demonstrated that an irradiation duration of 5min is enough with a 0.8M concentration of 1-octadecanethiol in solution or that it may be replaced by successive irradiations at a lower ODT concentration (0.19M) with renewing of the solution between the illuminations. Retention factors as high as those obtained with standard silanization are reached while keeping the intrinsic monolith permeability and efficiency (160,000plates/m in nano-LC at 0.7mm/s). The absence of polymerization, in the "ene-thiol" version, is demonstrated. Indeed, the steric selectivity of our clicked-material is characteristic of monolayer-like functionalized silica and significantly lower than the steric selectivity measured on polymeric-like functionalized silica.

BTES and aldehydes analysis in PET-bottled water in Lebanon.

The aim of this study was to determine benzene, toluene, ethylbenzene, styrene (BTES), formaldehyde, acetaldehyde and benzaldehyde in Lebanese polyethylene terephthalate (PET)-bottled water. Aldehydes were analysed by high-performance liquid chromatography with ultraviolet-visible detection (HPLC/UV-vis) after 2,4-dinitrophenylhydrazine (DNPH) derivatisation and solid phase extraction (SPE) concentration, whereas headspace trap gas chromatograph-flame ionisation detector (GC/FID) was used for BTES determination. Both methods were validated according to the NF XP 90-210 and showed good linearity ranging from 3 (limit of quantification [LOQ]) to 15 µg L⁻¹ for BTES and from 20 (LOQ) to 900 µg L⁻¹ for aldehydes. No quantified contamination with BTES, acetaldehyde and benzaldehyde was determined in all analysed fresh Lebanese PET-bottled waters. Formaldehyde was quantified in 3 of the 15 samples at concentrations lower than the maximum contaminant level set by the US Environmental Protection Agency and the World Health Organisation. The samples' exposure to sunlight during 5 months increases the migration of formaldehyde and acetaldehyde. Similar migration increase was observed when the samples were incubated at 40°C during 10 days.