Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
1.
PLOS Glob Public Health ; 3(3): e0001299, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36976760

RESUMO

Persisting sociocultural beliefs have continued to significantly influence the adoption of recommended newborn care practices by women in Sub-Saharan Africa. This study aimed at identifying the sociocultural practices, beliefs, and myths surrounding newborn cord care by women residing in Bayelsa State, Nigeria. This was a qualitative study that involved 24 women and 3 traditional birth attendants (TBAs) in three focus group discussions and three in-depth interviews respectively. Interview guides were used to lead the discussions and the interviews which were audiotaped, translated and then transcribed. Thematic analysis was done using NVivo QSR version 12.2 Pro. Several themes describing various sociocultural practices, beliefs, and myths surrounding cord care were uncovered. Most women preferred to be delivered by a TBA who usually cuts the infant's cord with a razor blade and ties the stump with hair or sewing thread. Substances used for cord care included methylated spirirt, "African never-die" leaf, and "Close-Up" toothpaste. All the participants agreed that methylated spirit was a potent antiseptic for cord care but none of them had heard about nor used chlorhexidine gel. It was a common belief that abdominal massage and the application of substances to the cord were solutions to common cord-related problems. Mothers, TBAs and relatives were influential regarding choices of cord care practices. Sociocultural practices, beliefs, and myths are still major barriers to the adoption of recommended cord care practices by women in Bayelsa State. Interventions should be targeted at improving delivery in health facilities and educating women in the community on good cord care practices.

2.
J Anim Sci ; 99(8)2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34022042

RESUMO

Effects of dried distillers grains plus solubles (DDGS) on ruminal fermentation, degradation kinetics, and feeding behavior of steers offered annual (Eragrostis tef; TEFF) or perennial (Bothriochloa bladhii; OWB) grass hay were evaluated. Ruminally cannulated Angus crossbred steers (n = 6; body weight [BW] = 304 ± 11 kg) were assigned to a 4 × 6 unbalanced Latin square design with four treatments arranged as a 2 × 2 factorial: hay type (OWB or TEFF) and DDGS supplementation (0% or 0.5% BW [dry matter {DM} basis]). Steers had ad libitum access to hay. Periods consisted of a 14-d adaptation followed by 7 d of collection. Residues from the in situ incubations (0, 3, 6, 12, 24, 36, 48, 72, and 96 h post-feeding) were fitted to a first-order kinetics model using the NLIN procedure of SAS. The DDGS decreased (P < 0.01) TEFF DM intake (DMI) by 11.3%, while not affecting DMI of OWB. The greatest DMI was observed for steers supplemented with DDGS, regardless of forage, and least in steers consuming OWB without DDGS (hay type × DDGS; P = 0.03). Non-supplemented steers spent more (P < 0.01) time eating hay. Digestibility of DM tended (P = 0.06) to increase with DDGS supplementation. A hay type × DDGS interaction was observed (P ≤ 0.05) on ruminal effective degradable fractions. The rate of degradation, soluble fraction, and the potentially degradable fraction of organic matter (OM), neutral detergent fiber, and acid detergent fiber (ADF) increased (P ≤ 0.05), while the undegradable fraction of all components decreased (P ≤ 0.01) when steers were offered TEFF compared to OWB. Ruminal DM, OM, and ADF degradation lag-time increased (P ≤ 0.02) in steers offered OWB. Ruminal degradation kinetics were not (P ≥ 0.17) independently affected by DDGS supplementation. Average ruminal pH of steers offered TEFF (P < 0.01) and those offered DDGS (P < 0.01) were lower than OWB and non-supplemented steers. Total concentration of VFA tended (P = 0.09) to increase when DDGS was provided with OWB, while decreasing when TEFF was offered. The acetate:propionate increased (P < 0.01) with DDGS supplementation due to a decrease (P = 0.03) in propionate. Ruminal NH3-N was greater (P = 0.03) in steers offered TEFF compared to OWB, and those supplemented with DDGS (P = 0.03). An annual, in place of a conventional, perennial hay improved intake and digestion of nutrients, without affecting feeding behavior. The supplementation with DDGS appears to affect forage intake, ruminal degradation, and feeding behavior, although not independent of forage quality.


Assuntos
Digestão , Rúmen , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Suplementos Nutricionais , Comportamento Alimentar , Fermentação , Cinética , Rúmen/metabolismo
3.
J Chromatogr A ; 1378: 74-87, 2015 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-25553910

RESUMO

Although bicyclic acids have been reported to be the major naphthenic acids in oil sands process-affected water (OSPW) and a well-accepted screening assay indicated that some bicyclics were the most acutely toxic acids tested, none have yet been identified. Here we show by comprehensive multidimensional gas chromatography-mass spectrometry (GC×GC-MS), that >100 C8-15 bicyclic acids are typically present in OSPW. Synthesis or purchase allowed us to establish the GC×GC retention times of methyl esters of numerous of these and the mass spectra and published spectra of some additional types, allowed us to identify bicyclo[2.2.1]heptane, bicyclo[3.2.1]octane, bicyclo[4.3.0]nonane, bicyclo[3.3.1]nonane and bicyclo[4.4.0]decane acids in OSPW and a bicyclo[2.2.2]octane acid in a commercial acid mixture. The retention positions of authentic bicyclo[3.3.0]octane and bicyclo[4.2.0]octane carboxylic acid methyl esters and published retention indices, showed these were also possibilities, as were bicyclo[3.1.1]heptane acids. Bicyclo[5.3.0]decane and cyclopentylcyclopentane carboxylic acids were ruled out in the samples analysed, on the basis that the corresponding alkanes eluted well after bicyclo[4.4.0]decane (latest eluting acids). Bicyclo[4.2.1]nonane, bicyclo[3.2.2]nonane, bicyclo[3.3.2]decane, bicyclo[4.2.2]decane and spiro[4.5]decane carboxylic acids could not be ruled out or in, as no authentic compounds or literature data were available. Mass spectra of the methyl esters of the higher bicyclic C12-15 acids suggested that many were simply analogues of the acids identified above, with longer alkanoate chains and/or alkyl substituents. Our hypothesis is that these acids represent the biotransformation products of the initially somewhat more bio-resistant bicyclanes of petroleum. Although remediation studies suggest that many bicyclic acids can be relatively quickly removed from suitably treated OSPW, examination by GC×GC-MS may show which isomers are affected most. Knowledge of the structures will allow the toxicity of any residual isomers to be calculated and measured.


Assuntos
Ácidos Carboxílicos/análise , Cromatografia Gasosa-Espectrometria de Massas , Campos de Petróleo e Gás/química , Poluentes Químicos da Água/análise , Alcanos/análise , Ácidos Carboxílicos/isolamento & purificação , Ésteres/análise , Petróleo/análise
4.
Rapid Commun Mass Spectrom ; 28(9): 1023-32, 2014 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-24677524

RESUMO

RATIONALE: The identification of key acid metabolites ('signature' metabolites) has allowed significant improvements to be made in our understanding of the biodegradation of petroleum hydrocarbons, in reservoir and in contaminated natural systems, such as aquifers and seawater. On this basis, anaerobic oxidation is now more widely accepted as one viable mechanism, for instance. However, identification of metabolites in the complex acid mixtures from petroleum degradation is challenging and would benefit from use of more highly resolving analytical methods. METHODS: Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GCxGC/TOFMS) with both nominal mass and accurate mass measurement was used to study the complex mixtures of aromatic acids (as methyl esters) in petroleum fractions. RESULTS: Numerous mono- and di-aromatic acid isomers were identified in a commercial naphthenic acids fraction from petroleum and in an acids fraction from a biodegraded petroleum. In many instances, compounds were identified by comparison of mass spectral and retention time data with those of authentic compounds. CONCLUSIONS: The identification of a variety of alkyl naphthalene carboxylic and alkanoic and alkyl tetralin carboxylic and alkanoic acids, plus identifications of a range of alkyl indane acids, provides further evidence for 'signature' metabolites of biodegradation of aromatic petroleum hydrocarbons. Identifications such as these now offer the prospect of better differentiation of metabolites of bacterial processes (e.g. aerobic, methanogenic, sulphate-reducing) in polar petroleum fractions.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Hidrocarbonetos Aromáticos/análise , Petróleo/análise , Biodegradação Ambiental
5.
Rapid Commun Mass Spectrom ; 27(2): 357-65, 2013 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-23239384

RESUMO

RATIONALE: The large volumes of 'supercomplex' mixtures of reputedly toxic organic compounds in acidic extracts of oil sands process-affected waters (OSPW) represent a challenging goal for complete characterisation. To date, comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GCxGC/TOFMS) has allowed the acquisition and interpretation of numerous electron ionisation mass spectra including many of those confirmed to be tricyclic and pentacyclic carboxylic acids by reference to the spectra and retention positions of authentic or synthetic compounds. This has allowed the toxicities of some of the identified acids to be determined and their environmental significance to be better assessed. METHODS: Synthesis, derivatisation (methyl, trideuteriomethyl and trimethylsilyl esters) and GCxGC/TOFMS with nominal mass and higher mass accuracy (ca. 5 ppm) were used to study three abundant unknown acids present in OSPW samples from two different industrial suppliers. RESULTS: GCxGC/TOFMS with nominal mass accuracy, of methyl, trideuteriomethyl and trimethylsilyl esters of three abundant acids in two OSPW samples, produced mass spectra consistent with their assignment as either C(16) tetracyclic acids or as isobaric pentacyclic C(15) hydroxy acids ('O(3)') or sulfur-containing ('SO(2)') species. The synthesis of several isomeric pentacyclic C(15) hydroxy acids and examination of the GCxGC retention times and mass spectra (nominal mass) of their derivatives suggested that the unknown OSPW acids were not hydroxy acids, and GCxGC/TOFMS with higher mass accuracy ruled out the possibility. The possibility that they were isobaric 'SO(2)' species could also be dismissed as this was inconsistent with accurate masses, the derivatisation reactions observed, the fragmentation patterns and the isotope distributions, which excluded the presence of sulphur. CONCLUSIONS: The data support the contention that the three abundant unknowns were indeed C(16) tetracyclic acids. An equally rigorous approach will be necessary to characterise further acids in such mixtures. This is important so that chemistry can be used to guide the search for toxic modes of action.


Assuntos
Ácidos Carboxílicos/análise , Ácidos Carboxílicos/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Campos de Petróleo e Gás/química , Ésteres/análise , Ésteres/química , Petróleo
6.
Sci Total Environ ; 425: 119-27, 2012 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-22464029

RESUMO

Naphthenic acids (NAs) are considered to be a major toxic component of oil sands process-affected waters (OSPW) and are also widely used for industrial processes. The effects of previously identified NAs (54 in total), together with six alkylphenols, were modelled for a range of environmental and human toxicity related endpoints using ADMET predictor™ software. In addition to the models, experimental CALUX® assays were performed on seven tricyclic diamondoid acids. Most of the NAs modelled were predicted to have lethal median concentrations (LC(50)) >100 µM for the three aquatic species modelled. Polycyclic acids containing a single aromatic ring were predicted to be the most toxic to fathead minnows with LC(50)s typically ca 1 µM. Some of these compounds were also predicted to be the most carcinogenic (based on rat and mouse models), possess human estrogenic and androgenic activity and potentially disrupt reproductive processes. Some aliphatic pentacyclic acids also were predicted to exhibit androgenic activity and, uniquely amongst the compounds tested, act as substrates for the cytochrome P450 enzyme CYP3A4. Consistent with the models' predictions for the tricyclic acids, no estrogenic or androgenic activity was detected by ER/AR CALUX®. Further experimental validation of the predictions should now be performed for the compounds highlighted by the models (e.g. priority should perhaps be focused on the polycyclic monoaromatic acids and the aliphatic pentacyclic acids). If shown to be accurate, these compounds can then be targeted for toxicity reduction remediation efforts.


Assuntos
Ácidos Carboxílicos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Carcinógenos/toxicidade , Cyprinidae , Citocromo P-450 CYP3A/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Disruptores Endócrinos/química , Disruptores Endócrinos/toxicidade , Indústrias Extrativas e de Processamento , Humanos , Dose Letal Mediana , Fígado/efeitos dos fármacos , Camundongos , Petróleo , Ratos , Relação Estrutura-Atividade , Testes de Toxicidade , Poluentes Químicos da Água/química
7.
Int J Gynaecol Obstet ; 117(1): 61-5, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22265191

RESUMO

OBJECTIVE: To assess the availability of prenatal care and basic emergency obstetric care services at primary healthcare (PHC) facilities in rural Nigeria. METHODS: In total, 652 PHC facilities enrolled in the Midwives Service Scheme, a government-funded program designed to reduce the national shortage of skilled birth attendants, were surveyed. RESULTS: In all, 44.0% of the PHC facilities evaluated did not provide all components of prenatal care, and only 39.0% of all pregnant women nationwide attended prenatal care clinics 4 or more times. In addition, 52.2% of the facilities were not distributing insecticide-treated nets to pregnant women, while only 36.8% of the PHC facilities provided services to prevent mother-to-child transmission of HIV. By contrast, 70.0% of the PHC facilities had access to antibiotics for the treatment of uncomplicated sepsis. Only 11.0% of clinics reported the use of vacuum extraction during labor and 36.8% provided post-abortion care services. Treatment for pre-eclampsia and eclampsia was initiated at 40.0% and 28.0% of PHC facilities, respectively, prior to referral. CONCLUSION: The present study provides useful information on the state of prenatal and basic emergency obstetric care in rural Nigeria. The data obtained indicate that changes are needed to achieve related Millennium Development Goals.


Assuntos
Serviços Médicos de Emergência/provisão & distribuição , Infecções por HIV/transmissão , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Cuidado Pré-Natal , Atenção Primária à Saúde , Serviços de Saúde Rural/provisão & distribuição , Antibacterianos/provisão & distribuição , Eclampsia/terapia , Feminino , Acessibilidade aos Serviços de Saúde , Humanos , Serviços de Saúde Materna/provisão & distribuição , Tocologia , Nigéria , Aceitação pelo Paciente de Cuidados de Saúde , Pré-Eclâmpsia/terapia , Gravidez , Vácuo-Extração/estatística & dados numéricos
8.
Environ Microbiol ; 14(4): 872-82, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22118473

RESUMO

Naphthenic acids (NAs) are complex mixtures of carboxylic acids found in weathered crude oils and oil sands, and are toxic, corrosive and persistent. However, little is known about the microorganisms and mechanisms involved in NA degradation. We isolated a sediment bacterium (designated strain IS2.3), with 100% 16S rRNA gene sequence identity to Mycobacterium aurum, which degraded synthetic NAs (4'-n-butylphenyl)-4-butanoic acid (n-BPBA) and (4'-t-butylphenyl)-4-butanoic acid (t-BPBA). n-BPBA was readily oxidized with almost complete degradation (96.8% ± 0.3) compared with t-BPBA (77.8% ± 3.7 degraded) by day 49. Cell counts increased fourfold by day 14 but decreased after day 14 for both n- and t-BPBA. At day 14, (4'-butylphenyl)ethanoic acid (BPEA) metabolites were detected. Additional metabolites produced during t-BPBA degradation were identified by mass spectrometry of derivatives as (4'-carboxy-t-butylphenyl)-4-butanoic acid and (4'-carboxy-t-butylphenyl)ethanoic acid; suggesting that strain IS2.3 used omega oxidation of t-BPEA to oxidize the tert-butyl side-chain to produce (4'-carboxy-t-butylphenyl)ethanoic acid, as the primary route for biodegradation. However, strain IS2.3 also produced this metabolite through initial omega oxidation of the tert-butyl side-chain of t-BPBA, followed by beta-oxidation of the alkanoic acid side-chain. In conclusion, an isolate belonging to the genus Mycobacterium degraded highly branched aromatic NAs via two different pathways.


Assuntos
Ácidos Carboxílicos/metabolismo , Mycobacterium/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Aerobiose , Sequência de Bases , Biodegradação Ambiental , Biotransformação , Ácidos Carboxílicos/análise , Espectrometria de Massas , Dados de Sequência Molecular , Mycobacterium/genética , Mycobacterium/isolamento & purificação , Petróleo/metabolismo , Poluentes do Solo/análise
9.
Environ Sci Technol ; 45(22): 9806-15, 2011 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22014158

RESUMO

The large volumes, acute toxicity, estrogenicity, and antiandrogenicity of process-affected waters accruing in tailings ponds from the operations of the Alberta oil sands industries pose a significant task for environmental reclamation. Synchronous fluorescence spectra (SFS) suggest that oil sands process-affected water (OSPW) may contain aromatic carboxylic acids, which are among the potentially environmentally important toxicants, but no such acids have yet been identified, limiting interpretations of the results of estrogenicity and other assays. Here we show that multidimensional comprehensive gas chromatography-mass spectrometry (GCxGC-MS) of methyl esters of acids in an OSPW sample produces mass spectra consistent with their assignment as C(19) and C(20) C-ring monoaromatic hydroxy steroid acids, D-ring opened hydroxy and nonhydroxy polyhydrophenanthroic acids with one aromatic and two alicyclic rings and A-ring opened steroidal keto acids. High resolution MS data support the assignment of several of the so-called 'O3' species. When fractions of distilled, esterified, OSPW acid-extractable organics were examined, the putative aromatics were mainly present in a high boiling fraction; when examined by argentation thin layer chromatography, some were present in a fraction with a retardation factor between that of the methyl esters of synthetic monoalicyclic and monoaromatic acids. Ultraviolet absorption spectra of these fractions indicated the presence of benzenoid moieties. SFS of model octahydro- and tetrahydrophenanthroic acids produced emissions at the characteristic excitation wavelengths observed in some OSPW extracts, consistent with the postulations from ultraviolet spectroscopy and mass spectrometry data. We suggest the acids originate from extensive biodegradation of C-ring monoaromatic steroid hydrocarbons and offer a means of differentiating residues at different biodegradation stages in tailings ponds. Structural similarities with estrone and estradiol imply that such compounds may account for some of the environmental estrogenic activity reported in OSPW acid-extractable organics and naphthenic acids.


Assuntos
Ácidos Carboxílicos/análise , Poluentes Ambientais/análise , Estrogênios/química , Petróleo/análise , Dióxido de Silício/química , Água/química , Ácidos Carboxílicos/química , Poluentes Ambientais/química , Cromatografia Gasosa-Espectrometria de Massas
10.
Environ Sci Technol ; 45(14): 6160-6, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21671574

RESUMO

Alkylnaphthalenes (AN) are relatively water-soluble hydrocarbons which, following spillages of crude oils, have been widely reported in contaminated marine organisms such as mussels. In the present report we show, by tandem-gas chromatography-time-of-flight-mass spectrometry (GC × GC-ToF-MS), that the range of AN in contaminated wild mussels from the UK extends beyond the previously GC resolved isomers to those with at least seven substituent carbon atoms. Since surprisingly little information on AN toxicity to such marine organisms has been reported we synthesized two C(8) AN and measured the toxicity of C(2-8) AN to mussels (clearance rate assay). C(2-3) AN were appreciably toxic (concentration for 50% clearance rate inhibition, 48 h IC(50) 1.4-2.6 µmol g(-1) dry weight tissue), but several C(4), (6) and C(8) AN, including branched isomers expected to be resistant to biodegradation and more accumulative, were relatively nontoxic (48 h IC(50) > 10 µmol g(-1)) and longer term exposure (8d) failed to elicit a greater toxic response. The accumulation profiles of AN in laboratory mussels exposed to oil were similar to those of the wild mussels. Moreover, laboratory oil-exposed mussels depurated toxic C(2-3) AN within 5 days in clean water and clearance rates recovered. The latter might imply that, in contrast with branched alkyl benzenes tested previously, AN are of less toxic concern, but such a straightforward conclusion cannot necessarily be drawn; a synthetic branched C(8) AN persisted following depuration and was as toxic to mussels as a C(3) AN (IC(50) 1.3 µmol g(-1)). This indicates that the structures of AN are also important.


Assuntos
Bivalves/metabolismo , Poluentes Ambientais/análise , Naftalenos/análise , Petróleo/análise , Animais , Bivalves/efeitos dos fármacos , Inglaterra , Poluentes Ambientais/toxicidade , Cromatografia Gasosa-Espectrometria de Massas , Concentração Inibidora 50 , Estrutura Molecular , Naftalenos/química , Naftalenos/toxicidade , Fatores de Tempo
11.
Rapid Commun Mass Spectrom ; 25(12): 1741-51, 2011 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-21598334

RESUMO

The identification of most individual members of the complex mixtures of carboxylic acids found in petroleum ('naphthenic acids') has eluded chemists for over a century; they remain unresolved by conventional gas chromatographic methods. Recently, however, we successfully used two-dimensional comprehensive gas chromatography/mass spectrometry to identify numerous individual diamondoid acids in the naphthenic acids of oil sands process water (OSPW). We have now applied the same methods to a study of a mixture of commercially available naphthenic acids originally refined from petroleum. The results confirm that OSPW and refined petroleum contain very different distributions of acids, as noted previously, although some of the diamondoid acids recently identified in OSPW were detectable in both. Rather, two-dimensional comprehensive gas chromatography/time-of-flight mass spectrometry (GCxGC/ToF-MS) of the methyl esters of the petroleum acids and of numerous acids synthesised for comparison showed that the former comprised mainly C(8-18) straight-chain, methyl-branched, acyclic isoprenoid, cyclohexyl and isomeric octahydropentalene, perhydroindane and perhydronaphthalene (decalin) acids. Some of the latter bicyclic acids occurred as both the non-alkyl-substituted isomers and the bicyclic ethanoic and propanoic acids. Also present in minor quantities was a range of phenyl carboxylic and substituted phenyl alkanoic acids, and traces of non-acids, including trimethylnaphthalenes, again identified by comparison with the synthesised compounds. These results represent some of the first identifications of multiple individual naphthenic acids in commercial mixtures originating from petroleum and provide a basis for future studies of the petroleum geochemistry, toxicities and environmental impacts of the acids. Furthermore, characterisation of the acids will be important for improving the understanding of the role of naphthenic acids in petroleum engineering, particularly for oil pipeline deposition problems.


Assuntos
Ácidos Carboxílicos/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Petróleo/análise , Ácidos Carboxílicos/química , Indústrias Extrativas e de Processamento , Espectrometria de Massas por Ionização por Electrospray
12.
Rapid Commun Mass Spectrom ; 25(9): 1198-204, 2011 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-21488118

RESUMO

The oils sands industry of Canada produces large volumes of process water (OSPW) which is stored in large lagoons. The OSPW contains complex mixtures of somewhat toxic, water-soluble, acid-extractable organic matter sometimes called 'naphthenic acids' (NA). Concerns have been raised over the possible environmental impacts of leakage of OSPW and a need has therefore arisen for better characterisation of the NA. Recently, we reported the first identification of numerous individual tricyclic NA in OSPW by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GCxGC/ToF-MS) of the methyl esters. The acids were diamondoid adamantane acids, resulting, it was proposed, from biotransformation of the corresponding alkyladamantane hydrocarbons, which is a known process. Biotransformation of higher alkylated diamondoid hydrocarbons was, until now, unknown but here we describe the identification of numerous pentacyclic NA as diamantane and alkyldiamantane acids, using the same methods. Further, we suggest tentative structures for some of the tetracyclic acids formed, we propose, by ring-opening of alkyldiamantanes. We suggest that this is further evidence that some of the acid-extractable organic matter in the OSPW originates from extensive biodegradation of the oil, whether in-reservoir or environmental, although other oxidative routes (e.g. processing) may also be possible. The results may be important for helping to better focus reclamation and remediation strategies for NA and for facilitating the identification of the sources of NA in contaminated environmental samples.


Assuntos
Adamantano/química , Ácidos Carboxílicos/química , Indústrias Extrativas e de Processamento , Cromatografia Gasosa-Espectrometria de Massas/métodos , Petróleo , Dióxido de Silício/química , Canadá , Água , Poluentes Químicos da Água/química
13.
Environ Sci Technol ; 45(7): 3154-9, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21391632

RESUMO

Expansion of the oil sands industry of Canada has seen a concomitant increase in the amount of process water produced and stored in large lagoons known as tailings ponds. Concerns have been raised, particularly about the toxic complex mixtures of water-soluble naphthenic acids (NA) in the process water. To date, no individual NA have been identified, despite numerous attempts, and while the toxicity of broad classes of acids is of interest, toxicity is often structure-specific, so identification of individual acids may also be very important. Here we describe the chromatographic resolution and mass spectral identification of some individual NA from oil sands process water. We conclude that the presence of tricyclic diamondoid acids, never before even considered as NA, suggests an unprecedented degree of biodegradation of some of the oil in the oil sands. The identifications reported should now be followed by quantitative studies, and these used to direct toxicity assays of relevant NA and the method used to identify further NA to establish which, or whether all NA, are toxic. The two-dimensional comprehensive gas chromatography-mass spectrometry method described may also be important for helping to better focus reclamation/remediation strategies for NA as well as in facilitating the identification of the sources of NA in contaminated surface waters.


Assuntos
Ácidos Carboxílicos/análise , Diamante/análise , Petróleo/metabolismo , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Biotransformação , Ácidos Carboxílicos/química , Ácidos Carboxílicos/metabolismo , Diamante/química , Diamante/metabolismo , Indústrias Extrativas e de Processamento , Cromatografia Gasosa-Espectrometria de Massas , Resíduos Industriais/análise , Dióxido de Silício , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
14.
Psychopharmacology (Berl) ; 182(1): 9-23, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16047194

RESUMO

RATIONALE AND OBJECTIVE: This paper describes a new procedure for detecting effective antidepressant treatments. The procedure uses the swim-test susceptible (Susceptible) rat which has been selectively bred to show decreased struggling behavior in a swim test after exposure to a mild stressor. The ability of treatments to block this decrease in swim-test activity was assessed as a method for detecting effective antidepressants. RESULTS: In both male and female Susceptible rats, chronic (14-day) treatment with different antidepressant drugs delivered via osmotic minipump [i.e., three tricyclics (desmethylimipramine, imipramine, amitriptyline), two selective serotonin reuptake inhibitors (fluoxetine and sertraline), a monoamine oxidase inhibitor (phenelzine), and two atypical antidepressants (venlafaxine and bupropion)] all prevented the stress-induced decrease in swim-test struggling normally shown by these rats. Electroconvulsive shock had a similar effect. Unlike antidepressant drugs, 14-day treatment with various non-antidepressant drugs [i.e., a stimulant (amphetamine), an anxiolytic (chlordiazepoxide), an antihistamine (chlorpheniramine), and an anticholinergic (scopolamine)] did not have this effect. Antidepressant drug treatment for 1 day (i.e., acute treatment) was also ineffective in this test. The procedure described above requires use of the Susceptible rat--swim test resistant rats (i.e., rats selectively bred to be resistant to decreased swim-test activity after exposure to stressful conditions) showed no significant differences in swim-test behavior between stress and nonstress conditions after 14-day drug treatment, and randomly bred Sprague-Dawley rats did not show a decrease in swim-test activity following exposure to the mild stressor that is the basis for the test. CONCLUSION: These results suggest that the procedure described here, which uses a rat subject that has been bred for vulnerability to stressful conditions, may be a selective screening technique for effective antidepressant treatments.


Assuntos
Antidepressivos/farmacologia , Reação de Fuga/efeitos dos fármacos , Medo/efeitos dos fármacos , Atividade Motora/efeitos dos fármacos , Estresse Psicológico/complicações , Animais , Avaliação Pré-Clínica de Medicamentos , Eletrochoque , Feminino , Masculino , Ratos , Ratos Endogâmicos , Ratos Sprague-Dawley , Natação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA