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1.
Alzheimers Dement ; 16(11): 1493-1503, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32755010

RESUMEN

INTRODUCTION: Reference materials based on human cerebrospinal fluid were certified for the mass concentration of amyloid beta (Aß)1-42 (Aß42 ). They are intended to be used to calibrate diagnostic assays for Aß42 . METHODS: The three certified reference materials (CRMs), ERM-DA480/IFCC, ERM-DA481/IFCC and ERM-DA482/IFCC, were prepared at three concentration levels and characterized using isotope dilution mass spectrometry methods. Roche, EUROIMMUN, and Fujirebio used the three CRMs to re-calibrate their immunoassays. RESULTS: The certified Aß42 mass concentrations in ERM-DA480/IFCC, ERM-DA481/IFCC, and ERM-DA482/IFCC are 0.45, 0.72, and 1.22 µg/L, respectively, with expanded uncertainties (k = 2) of 0.07, 0.11, and 0.18 µg/L, respectively. Before re-calibration, a good correlation (Pearson's r > 0.97), yet large biases, were observed between results from different commercial assays. After re-calibration the between-assay bias was reduced to < 5%. DISCUSSION: The Aß42 CRMs can ensure the equivalence of results between methods and across platforms for the measurement of Aß42 .


Asunto(s)
Péptidos beta-Amiloides/líquido cefalorraquídeo , Inmunoensayo/normas , Calibración , Humanos , Inmunoensayo/métodos , Estándares de Referencia
2.
Children (Basel) ; 7(6)2020 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-32549197

RESUMEN

Nephrotic syndrome is the most common glomerular disease among children. Although most cases respond to steroid therapy, approximately 10-20% of patients exhibit resistance to conventional steroid therapy and are labeled as steroid-resistant. Such patients are at risk of complications, including infection, thrombosis, and chronic kidney disease. Nephrotic syndrome is considered a thrombogenic condition. Pulmonary embolism is associated with high mortality, and early treatment is essential for the survival of patients. Here, we report the case of a 12-year-old girl with late steroid resistance who developed bilateral pulmonary embolism.

3.
Cureus ; 12(12): e12148, 2020 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-33489560

RESUMEN

Background Acne vulgaris is one of the most common diseases worldwide. It is a chronic, relapsing inflammatory skin disease. Nearly anyone can be affected at any age. Adolescents and young adults are more susceptible, with a prevalence as high as 35% to 90% and reaching up to 100% in both sexes. Isotretinoin is the most effective medication to be used. It has been reported in the literature that many populations are non-adherents to or aware of safety recommendations. This study aims to assess females' awareness and safety of isotretinoin use in the western region of Saudi Arabia. Methods This is a cross-sectional, descriptive study. A semi-structured questionnaire was used, data was collected from an electronic validated survey and published on a social platform. Statistical analysis was conducted with the aid of Statistical Package for Social Sciences (SPSS) version 21 (IBM Corp., Armonk, NY, USA). Results The total number of included responses was 1066. Most of the participants were 12-22 years old (45.2%), single (72.2%) and had a bachelor's degree (69.6%). Among the total number of participants there were 285 participants who used isotretinoin. Ninety-three percent of them had a prescription of isotretinoin from a physician. The common dose given was approximately 20 mg and the common duration was more than six months. Conclusion There is a good amount of knowledge in our population regarding isotretinoin side effects, although only half of them were informed about them by their treating physicians. We noticed an obvious lack of awareness about safe practice during childbearing age and marriage. This highlights the need for optimal education by health care providers and the role of media is obvious to improve their practices and hopefully decrease the risks as it was the second most common source of information after dermatologists in our population. Also we recommend paying more attention to the psychological side effect which was reported by 9% of our participants.

4.
Arch Environ Contam Toxicol ; 77(1): 40-50, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30255342

RESUMEN

The use of chemical dispersants during oil spill responses has long been controversial. During the Deepwater Horizon (DWH) oil spill, 1.8 million gallons of dispersant, mainly Corexit 9500, were applied in offshore waters to mitigate the human health and coastal environmental impact of surface oil contamination. To evaluate the potential impact of the dispersant on marine life, 18 species, representing important ecological and commercial taxa, were tested using low-energy, dispersant-only water accommodated fractions (WAFs) of Corexit 9500 and standard acute toxicity test methods. All prepared WAFs were analytically characterized. Analyses included the two dispersant markers found in the dispersant and evaluated in samples collected during the DWH Response, dioctylsulfosuccinate sodium salt, and dipropylene glycol n-butyl ether (DPnB). The median lethal and effective concentrations (LC/EC50s) were calculated using a nominal exposure concentration (mg/L, based on the experimental loading rate of 50 mg/L) and measured DPnB (µg/L). Results ranged from 5.50 to > 50 mg/L dispersant and 492 to > 304,000 µg/L DPnB. Species sensitivity distributions of the data demonstrated that taxa were evenly distributed; however, algae and oysters were among the more sensitive organisms. The calculated 5% hazard concentration (HC5) for DPnB (1172 µg/L) was slightly higher than the USEPA chronic criteria of 1000 µg/L and substantially higher than all measured concentrations of DPnB measured in the Gulf of Mexico during the DWH oil spill response.


Asunto(s)
Organismos Acuáticos/efectos de los fármacos , Lípidos/toxicidad , Contaminación por Petróleo/efectos adversos , Contaminantes Químicos del Agua/toxicidad , Animales , Pruebas de Toxicidad Aguda
5.
Alzheimers Res Ther ; 10(1): 118, 2018 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-30486870

RESUMEN

BACKGROUND: Amyloid-ß 1-42 (Aß1-42) peptide is a well-established cerebrospinal fluid (CSF) biomarker for Alzheimer's disease (AD). Reduced levels of Aß1-42 are indicative of AD, but significant variation in the absolute concentrations of this analyte has been described for both healthy and diseased populations. Preanalytical factors such as storage tube type are reported to impact Aß recovery and quantification accuracy. Using complementary immunological and mass spectrometry-based approaches, we identified and characterized preanalytical factors that influence measured concentrations of CSF Aß peptides in stored samples. METHODS: CSF from healthy control subjects and patients with AD was aliquoted into polypropylene tubes at volumes of 0.1 ml and 0.5 ml. CSF Aß1-42 concentrations were initially measured by immunoassay; subsequent determinations of CSF Aß1-42, Aß1-40, Aß1-38, Aß1-37, and Aß1-34 concentrations were made with an absolute quantitative mass spectrometry assay. In a second study, CSF from healthy control subjects and patients with dementia was denatured with guanidine hydrochloride (GuHCl) at different stages of the CSF collection and aliquoting process and then measured with the mass spectrometry assay. RESULTS: Two distinct immunoassays demonstrated that CSF Aß1-42 concentrations measured from 0.5-ml aliquots were higher than those from 0.1-ml aliquots. Tween-20 surfactant supplementation increased Aß1-42 recovery but did not effectively resolve measured concentration differences associated with aliquot size. A CSF Aß peptide mass spectrometry assay confirmed that Aß peptide recovery was linked to sample volume. Unlike the immunoassay experiments, measured differences were consistently eliminated when aliquots were denatured in the original sample tube. Recovery from a panel of low-retention polypropylene tubes was assessed, and 1.5-ml Eppendorf LoBind® tubes were determined to be the least absorptive for Aß1-42. A comparison of CSF collection and processing methods suggested that Aß peptide recovery was improved by denaturing CSF earlier in the collection/aliquoting process and that the Aß1-42/Aß1-40 ratio was a useful method to reduce variability. CONCLUSIONS: Analyte loss due to nonspecific sample tube adsorption is a significant preanalytical factor that can compromise the accuracy of CSF Aß1-42 measurements. Sample denaturation during aliquoting increases recovery of Aß peptides and improves measurement accuracy. The Aß1-42/Aß1-40 ratio can overcome some of the quantitative variability precipitated by preanalytical factors affecting recovery.


Asunto(s)
Enfermedad de Alzheimer/líquido cefalorraquídeo , Péptidos beta-Amiloides/análisis , Péptidos beta-Amiloides/líquido cefalorraquídeo , Fase Preanalítica/métodos , Adulto , Anciano , Enfermedad de Alzheimer/diagnóstico , Biomarcadores/líquido cefalorraquídeo , Femenino , Humanos , Inmunoensayo/métodos , Masculino , Espectrometría de Masas/métodos , Persona de Mediana Edad
7.
Clin Chim Acta ; 467: 27-33, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27216941

RESUMEN

The 42 amino acid form of amyloid ß (Aß1-42) in cerebrospinal fluid (CSF) has been widely accepted as a central biomarker for Alzheimer's disease. Several immunoassays for CSF Aß1-42 are commercially available, but can suffer from between laboratory and batch-to-batch variability as well as lack of standardisation across assays. As a consequence, no general cut-off values have been established for a specific context of use (e.g., clinical diagnostics) and selection of individuals for enrolment in clinical trials (patient stratification) remains challenging. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has initiated a working group for CSF proteins (WG-CSF) to facilitate standardisation of CSF Aß1-42 measurement results. The efforts of the IFCC WG-CSF include the development of certified reference materials (CRMs) and reference measurement procedures (RMPs) for key biomarkers. Two candidate RMPs for quantification of Aß1-42 in CSF based on liquid chromatography tandem mass spectrometry have been developed and tested in two ring trials. Furthermore, two commutability studies including native CSF pools, artificial CSF and spiked materials have been completed. On the basis of these studies, human CSF pools containing only endogenous Aß1-42 at three concentrations were selected as the format for future CRMs that are now being processed.


Asunto(s)
Enfermedad de Alzheimer/líquido cefalorraquídeo , Péptidos beta-Amiloides/líquido cefalorraquídeo , Pruebas de Química Clínica/normas , Fragmentos de Péptidos/líquido cefalorraquídeo , Biomarcadores/líquido cefalorraquídeo , Humanos , Estándares de Referencia
9.
Arch Environ Contam Toxicol ; 71(1): 78-86, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27090525

RESUMEN

Chronic, 21-28-day toxicity tests of Macondo source (Massachusetts, or MASS) and weathered Slick A (CTC) and Slick B (Juniper) oils field collected during the 2010 Deepwater Horizon (DWH) Incident in the Gulf of Mexico (GOM) were conducted using standardized procedures. Standard species, Americamysis bahia and Menidia beryllina, were evaluated for changes in survival and growth during daily static-renewal tests. Both species demonstrated an increased sensitivity to low-energy water accommodated fractions (WAFs) of un-weathered MASS oil, with growth and survival decreasing as oil loading rate increased from 0.01 to 1.0 g/L. Survival and growth of mysid shrimp exposed to weathered oil (Slick A and Slick B) did not differ from that of test controls. In contrast, survival and growth of inland silversides declined relative to that of test controls at loading rates of 1 g/L for both weathered oils. Based on the concentration of total polycyclic aromatic hydrocarbons (TPAH42), no observed effect concentrations were lower for inland silverside survival (5.00-7.61 µg/L) and growth (<2.02 to <7.61 µg/L) in chronic exposures to Slick B and Slick A weathered oils compared with mysids (4.75-17.9 µg/L). Average TPAH concentrations in full strength WAFs followed the weathering trend, with 165 ± 17.2, 17.9 ± 0.480, and 4.75 ± 0.521 µg/L for MASS, Slick A, and Slick B oils, respectively. The effect (LOEC, IC25) and no-effect exposure concentrations (in TPAHs) from the standardized laboratory toxicity studies with un-weathered and weathered oils are discussed relative to the actual exposure concentrations in the GOM in 2010. The exposures evaluated in the laboratory toxicity tests represent the highest concentrations of total PAHs that were rarely observed in water column samples collected in the GOM during the release and post release periods of the DWH incident.


Asunto(s)
Crustáceos/fisiología , Perciformes/fisiología , Petróleo/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Monitoreo del Ambiente , Contaminación por Petróleo , Pruebas de Toxicidad Crónica
10.
Bioanalysis ; 8(8): 765-94, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27005848

RESUMEN

BACKGROUND: Knowledge of antipsychotic drug levels at point of care (POC) may significantly aid therapeutic decision-making. To support the development of future POC devices and to validate the use of fingerstick capillary blood sampling, two robust hydrophilic interaction LC-ESI/MS/MS methods were developed and validated. Two PK studies were completed evaluating the correlation between fingerstick blood and plasma concentrations with corresponding venous blood and plasma concentrations for several commonly prescribed atypical antipsychotics and selected metabolites. Sensitive and reliable LC-MS/MS bioanalytical assays were developed to support these studies. RESULTS: Three methods, requiring only 25-µl matrix volumes, were developed using supported liquid extraction with hydrophilic interaction LC-MS/MS detection and validated according to regulatory guidance. CONCLUSION: Robust and efficient LC-MS/MS assays were established and were effective in providing antipsychotic drug matrix comparator results in the intended clinical studies.


Asunto(s)
Antipsicóticos/sangre , Análisis Químico de la Sangre/métodos , Cromatografía Líquida de Alta Presión , Espectrometría de Masa por Ionización de Electrospray , Antipsicóticos/farmacocinética , Antipsicóticos/normas , Análisis Químico de la Sangre/normas , Calibración , Cromatografía Líquida de Alta Presión/normas , Semivida , Humanos , Sistemas de Atención de Punto , Reproducibilidad de los Resultados , Espectrometría de Masa por Ionización de Electrospray/normas
11.
Arch Environ Contam Toxicol ; 70(2): 392-405, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26467150

RESUMEN

In the wake of the Deepwater Horizon incident (2010) in the Gulf of Mexico, an abundance of research studies have been performed, but the methodologies used have varied making comparisons and replication difficult. In this study, acute toxicity tests with mysids and inland silversides were performed to examine the effect of different variables on test results. The toxicity test variables evaluated in this study included (1) open versus closed static test chambers, (2) natural versus artificial diluent, (3) aerated versus nonaerated test solution, and (4) low versus medium energy water-accommodated (WAF) mixing energies. The use of tests using natural or artificial diluent showed no difference in either toxicity test or analytical chemistry results. Based on median lethal concentrations (LC50) of WAFs of unweathered oil (MASS), mysid tests performed in closed chambers were approximately 41 % lower than LC50 values from open-chamber studies, possibly a result of the presence of low-molecular weight volatile aromatics (i.e., naphthalenes). This research also showed that using a medium-energy WAF (with a 20­25 % vortex) increases the number of chemical components compared with low-energy WAF, thus affecting the composition of the exposure media and increasing toxicity. The comparison of toxic units as a measure of the potential toxicity of fresh and weathered oils showed that weathered oils (e.g., Juniper, CTC) are less toxic than the unweathered MASS oil. In the event of future oil spills, these variables should be considered to ensure that data regarding the potential toxicity and environmental risk are of good quality and reproducible.


Asunto(s)
Monitoreo del Ambiente/métodos , Petróleo/toxicidad , Pruebas de Toxicidad Aguda , Contaminantes Químicos del Agua/toxicidad , Animales , México , Contaminación por Petróleo/estadística & datos numéricos , Smegmamorpha
12.
Chemosphere ; 144: 1893-900, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26547023

RESUMEN

Ephyrae of the scyphozoan jellyfish, Aurelia aurita, were evaluated in 96-hr acute toxicity tests for lethal response to Macondo crude oils from the Deepwater Horizon (DWH) incident in the Gulf of Mexico (GOM), Corexit 9500, and oil-dispersant mixtures. Water accommodated fractions (WAFs) of weathered and unweathered Macondo crude oils were not acutely toxic to ephyrae (LC50s > 100% WAF). The total PAHs (TPAHs), measured as the sum of 46 PAHs, averaged 21.1and 152 µg TPAH/L for WAFs of weathered and unweathered oil, respectively. Mortality was significantly (p = <0.0001) higher in the three highest exposure concentrations (184-736 µg TPAH/L) of chemically dispersed WAFs (CEWAF) compared to controls. Dispersant only tests resulted in a mean LC50 of 32.3 µL/L, which is in the range of previously published LC50s for marine zooplankton. Changes in appearance and muscle contractions were observed in organisms exposed to CEWAF dilutions of 12.5 and 25%, as early as 24 h post-exposure. Based on the results of these tests, crude oil alone did not cause significant acute toxicity; however, the presence of chemical dispersant resulted in substantial mortality and physical and behavioral abnormalities either due to an increase in hydrocarbons or droplet exposure.


Asunto(s)
Accidentes , Ecotoxicología , Contaminación por Petróleo , Petróleo/análisis , Escifozoos/efectos de los fármacos , Animales , Golfo de México , Lípidos/toxicidad , Hidrocarburos Policíclicos Aromáticos/toxicidad , Contaminantes Químicos del Agua/toxicidad
13.
Artículo en Inglés | MEDLINE | ID: mdl-26279007

RESUMEN

Human osteopontin (hOPN) is a secreted plasma protein which is elevated in various cancers and is indicative of poor prognosis. Here we describe investigations involving an extended peptide internal standard to track an unstable signature peptide followed by further method development and validation for quantitative measurement of hOPN from plasma using microflow liquid chromatography and tandem mass spectrometry (MFLC-MS/MS). A biologically relevant tryptic peptide 'GDSVVYGLR' was used as a signature peptide for this method. The optimized method involved immunocapture of the analyte protein using hOPN specific antibodies followed by trypsin digestion to obtain the signature peptide. Analysis was carried out on a Waters IonKey/MS system using a flow rate of 2.5µL/min. Immunocapture buffer was used as a surrogate matrix for the validation studies. The method was validated over a range of 25-600ng/mL. Intra-assay and inter-assay accuracies were within ±13%. Intra-assay and inter-assay precision were within 17%. A stable isotope labeled (SIL) peptide GDSVVYGLR* and an extended SIL peptide TYDGRGDSVV*YGLRSKSKKF were evaluated as internal standards (IS) to account for signature peptide digestion instability and variability. Inherent digestion variability i.e., under controlled conditions, was within ±20% with both IS peptides. In digestion variability studies, where trypsin activity was varied (20-180%), the use of the extended SIL peptide as an internal standard limited the variability to within ±30% of the normalized response. Alternatively, when the SIL peptide was used as the internal standard, the variability ranged from -67.4% to 50.6% of the normalized response. The applicability of the validated method was demonstrated by quantification of OPN from plasma samples obtained from 10 healthy individuals and 10 breast cancer patients. The plasma OPN concentrations in healthy individuals ranged from 38 to 85ng/mL with a mean concentration of 55.4±15.3ng/mL. A 1.5-12 fold increase in OPN concentrations, ranging from 85 to 637ng/mL, was seen in breast cancer patient samples.


Asunto(s)
Biomarcadores de Tumor/sangre , Cromatografía Liquida/métodos , Marcaje Isotópico , Neoplasias/sangre , Osteopontina/sangre , Péptidos/química , Espectrometría de Masas en Tándem/métodos , Humanos , Estándares de Referencia
14.
Biomed Chromatogr ; 29(11): 1780-2, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25919310

RESUMEN

A stable isotope-labeled signature peptide, whose sequence corresponds to the human osteopontin (hOPN) specific antibody epitope, was evaluated as an internal standard to compensate for immunocapture variability during quantification of hOPN by immunoaffinity-coupled LC-MS/MS. Immunocapture variability was induced by varying the antibody amount per well from 150 to 4500 ng and analysis was carried out with internal standards added before and after the immunocapture step. The immunocapture variability ranged from -80.9 to 77.0% when the IS was added after immunocapture and from -37.5 to 20.3% when the internal standard was added before immunocapture. The lower variability demonstrates the ability of stable labeled isotope internal standard peptide to compensate for variation during immunocapture.


Asunto(s)
Cromatografía de Afinidad/métodos , Marcaje Isotópico , Osteopontina/sangre , Espectrometría de Masas en Tándem/métodos , Humanos , Estándares de Referencia
15.
Arch Environ Contam Toxicol ; 68(4): 655-62, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25563746

RESUMEN

Indigenous species are less commonly used in laboratory aquatic toxicity tests compared with standard test species due to (1) limited availability lack of requisite information necessary for their acclimation and maintenance under laboratory conditions and (2) lack of information on their sensitivity and the reproducibility of toxicity test results. As part of the Natural Resource Damage Assessment aquatic toxicity program in response to the Deepwater Horizon Oil incident (2010), sensitive life stages of native Gulf of Mexico species were evaluated in laboratory toxicity tests to determine the potential effects of the spill. Fish (n = 5) and invertebrates (n = 2) selected for this program include the following: the Florida pompano (Trachinotus carolinus), red drum (Sciaenops ocellatus), spotted sea trout (Cynoscion nebulosus), cobia (Rachycentron canadum), red porgy (Pagrus pagrus), blue crab (Callinectes sapidus), and the common moon jellyfish (Aurelia aurita). Initially in the program, to establish part of the background information, acute tests with reference toxicants (CdCl2, KCl, CuSO4) were performed with each species to establish data on intraspecies variability and test precision as well as identify other factors that may affect toxicity results. Median lethal concentration (LC50) values were calculated for each acute toxicity test with average LC50 values ranging from 248 to 862 mg/L for fish exposures to potassium chloride. Variability between test results was determined for each species by calculating the coefficient of variation (%CV) based on LC50 values. CVs ranged from 11.2 % for pompano (96-h LC50 value) to 74.8 % for red porgy 24-h tests. Cadmium chloride acute toxicity tests with the jellyfish A. aurita had the lowest overall CV of 3.6 %. By understanding acute toxicity to these native organisms from a compound with known toxicity ranges and the variability in test results, acute tests with nonstandard species can be better interpreted and used appropriately when determining risk.


Asunto(s)
Organismos Acuáticos/fisiología , Pruebas de Toxicidad/normas , Contaminantes Químicos del Agua/toxicidad , Animales , Monitoreo del Ambiente/métodos , Peces , Golfo de México , Invertebrados
16.
Sci Total Environ ; 502: 252-65, 2015 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-25261815

RESUMEN

A comprehensive probabilistic terrestrial ecological risk assessment (ERA) was conducted to characterize the potential risk of mosquito control insecticide (i.e., naled, it's metabolite dichlorvos, and permethrin) usage to adult butterflies in south Florida by comparing the probability distributions of environmental exposure concentrations following actual mosquito control applications at labeled rates from ten field monitoring studies with the probability distributions of butterfly species response (effects) data from our laboratory acute toxicity studies. The overlap of these distributions was used as a measure of risk to butterflies. The long-term viability (survival) of adult butterflies, following topical (thorax/wings) exposures was the environmental value we wanted to protect. Laboratory acute toxicity studies (24-h LD50) included topical exposures (thorax and wings) to five adult butterfly species and preparation of species sensitivity distributions (SSDs). The ERA indicated that the assessment endpoint of protection, of at least 90% of the species, 90% of the time (or the 10th percentile from the acute SSDs) from acute naled and permethrin exposures, is most likely not occurring when considering topical exposures to adults. Although the surface areas for adulticide exposures are greater for the wings, exposures to the thorax provide the highest potential for risk (i.e., SSD 10th percentile is lowest) for adult butterflies. Dichlorvos appeared to present no risk. The results of this ERA can be applied to other areas of the world, where these insecticides are used and where butterflies may be exposed. Since there are other sources (e.g., agriculture) of pesticides in the environment, where butterfly exposures will occur, the ERA may under-estimate the potential risks under real-world conditions.


Asunto(s)
Mariposas Diurnas/efectos de los fármacos , Exposición a Riesgos Ambientales/estadística & datos numéricos , Insecticidas/toxicidad , Control de Mosquitos/métodos , Animales , Diclorvos/toxicidad , Monitoreo del Ambiente , Florida , Dosificación Letal Mediana , Naled/toxicidad , Permetrina/toxicidad , Medición de Riesgo/métodos
17.
Chemosphere ; 120: 131-7, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25016336

RESUMEN

The potential for the Deepwater Horizon MC-252 oil incident to affect ecosystems in the Gulf of Mexico (GOM) was evaluated using Americamysis bahia, Menidia beryllina and Vibrio fischeri (Microtox® assay). Organisms were exposed to GOM water samples collected in May-December 2010. Samples were collected where oil was visibly present on the water surface or the presence of hydrocarbons at depth was indicated by fluorescence data or reduced dissolved oxygen. Toxicity tests were conducted using water-accommodated fractions (WAFs), and oil-in-water dispersions (OWDs). Water samples collected from May to June 2010 were used for screening tests, with OWD samples slightly more acutely toxic than WAFs. Water samples collected in July through December 2010 were subjected to definitive acute testing with both species. In A. bahia tests, total PAH concentrations for OWD exposures ranged from non-detect to 23.0 µg L(-1), while WAF exposures ranged from non-detect to 1.88 µg L(-1). Mortality was >20% in five OWD exposures with A. bahia and three of the WAF definitive tests. Total PAH concentrations were lower for M. beryllina tests, ranging from non-detect to 0.64 µg L(-1) and non-detect to 0.17 µg L(-1) for OWD and WAF exposures, respectively. Only tests from two water samples in both the WAFs and OWDs exhibited >20% mortality to M. beryllina. Microtox® assays showed stimulatory and inhibitory responses with no relationship with PAH exposure concentrations. Most mortality in A. bahia and M. beryllina occurred in water samples collected before the well was capped in July 2010 with a clear decline in mortality associated with a decline in total PAH water concentrations.


Asunto(s)
Biota/efectos de los fármacos , Hidrocarburos/toxicidad , Contaminación por Petróleo/efectos adversos , Agua de Mar/química , Contaminantes Químicos del Agua/toxicidad , Aliivibrio fischeri/efectos de los fármacos , Animales , Crustáceos/efectos de los fármacos , Golfo de México , Hidrocarburos/análisis , Contaminación por Petróleo/análisis , Smegmamorpha/crecimiento & desarrollo , Pruebas de Toxicidad , Contaminantes Químicos del Agua/análisis
18.
Drug Test Anal ; 6(5): 415-25, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-23918459

RESUMEN

Online 2-dimensional chromatographic approaches for eliminating matrix effects and optimizing bioanalysis of peptides using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) were studied. Three therapeutic peptides (octreotide, desmopressin, and vasopressin) were selected as model analytes. Human plasma was precipitated with acetonitrile; peptides were analyzed on C(8), C(18), Phenyl and HILIC ACQUITY UPLC columns. For simpler online clean-up applications, a C(18) pre-column was coupled to the analytical column via a switching valve. For more complex heart-cutting applications, two analytical columns were used with optional online dilution to refocus the analyte peaks prior to the second dimension separation. This allows the use of MS incompatible mobile phases, such as TFA, in the first dimension separation. Online clean-up effectiveness was investigated by monitoring phospholipids. Flushing direction, mobile phase composition, flow rate and transfer window were evaluated. Phospholipids were readily retained on reversed-phase columns, and the peptides were reproducibly transferred, individually or as a group, to the second column using appropriate transfer windows. The best peak shapes were obtained when the second dimension column was more retentive (e.g. C(18) vs. C(8)). However, C(8) to HILIC gave broad unresolved peaks due to mobile phase mismatch. Trapped phospholipids were efficiently removed from either guard columns or first dimensional columns by forward- or back-flushing at high flows; however, back-flushing was more efficient with lower flow rates on larger columns.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Péptidos/sangre , Espectrometría de Masas en Tándem/métodos , Desamino Arginina Vasopresina/sangre , Humanos , Octreótido/sangre , Péptidos/química , Fosfolípidos/análisis , Vasopresinas/sangre
19.
Drug Test Anal ; 5(8): 710-5, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23055275

RESUMEN

Dried blood spot (DBS) sampling coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a rapidly developing approach in the field of biopharmaceutical analysis. DBS sampling enables analysis of small sample volumes with high sensitivity and selectivity while providing a convenient easy to store and ship format. Lipid components that may be extracted during biological sample processing may result in matrix ionization effects and can significantly affect the precision and accuracy of the results. Glycerophosphocholines (GPChos), cholesterols and triacylglycerols (TAG) are the main lipid components that contribute to matrix effects in LC-MS/MS. Various organic solvents such as methanol, acetonitrile, methyl tertiary butyl ether, ethyl ether, dichloromethane and n-hexane were investigated for elution of these lipid components from DBS samples. Methanol extracts demonstrated the highest levels of GPChos whereas ethyl ether and n-hexane extracts contained less than 1.0 % of the GPChos levels in the methanol extracts. Ethyl ether extracts contained the highest levels of cholesterols and TAG in comparison to other investigated organic solvents. Acetonitrile is recommended as an elution solvent due to low lipid recoveries. Matrix effects resulted from different extracted lipid components should be studied and assessed carefully in DBS samples.


Asunto(s)
Cromatografía Liquida/métodos , Pruebas con Sangre Seca/métodos , Lípidos/sangre , Espectrometría de Masas en Tándem/métodos , Colesterol/sangre , Ésteres del Colesterol/sangre , Humanos , Fosfatidilcolinas/sangre , Solventes , Triglicéridos/sangre
20.
Menopause ; 18(4): 393-9, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21107298

RESUMEN

OBJECTIVE: A randomized, parallel-design study was conducted to determine the pharmacokinetic profile of synthetic conjugated estrogens A (SCE-A) vaginal cream (0.625 mg SCE-A/g) when administered at intervals (1 g once daily for 7 d, then twice weekly) over a 27-day period as compared with the pharmacokinetic profile of 0.3 mg SCE-A tablets administered once daily orally for 27 days. METHODS: Blood samples were collected 48 hours before initial dosing for baseline levels and at multiple occasions during the study until 48 hours after final study dosing (day 29). Maximum plasma concentration, time to maximum plasma concentration (Tmax), and area under the curve from 0 to 24 hours were calculated at days 1, 7, and 27; in addition, area under the curve from 0 to 48 hours was calculated at days 7 and 27, and area under the curve weekly (AUCweekly) values were calculated for both groups. For purposes of comparison, ratios of AUCweekly values for vaginal cream and oral tablets were analyzed. RESULTS: Compared with an oral daily dose of 0.3 mg SCE-A, the steady-state systemic exposure from vaginal cream application was considerably less, with the cream-to-oral ratio being 0.45 for baseline-adjusted (BA) unconjugated estradiol, 0.30 for BA unconjugated estrone, and 0.04 for unconjugated equilin (AUCweekly). At steady-state, the systemic blood levels of BA unconjugated estrone, BA unconjugated estradiol and unconjugated equilin were significantly lower in women who received biweekly application of 1 gm vaginal cream compared to women who took an oral daily dose of 0.3 mg SCE-A tablet. CONCLUSIONS: After intravaginal application of SCE-A vaginal cream, absorption of estrogens was lower compared with absorption after oral administration. At steady state, the systemic exposure of equilin, estradiol, and estrone was significantly lower after twice-weekly administration of 1 g SCE-A vaginal cream compared with that achieved with an oral daily dose of a 0.3 mg SCE-A tablet.


Asunto(s)
Congéneres del Estradiol/farmacocinética , Posmenopausia , Comprimidos/administración & dosificación , Cremas, Espumas y Geles Vaginales/administración & dosificación , Adulto , Anciano , Cromatografía Líquida de Alta Presión , Equilina/sangre , Estradiol/sangre , Congéneres del Estradiol/administración & dosificación , Estrógenos/administración & dosificación , Estrógenos/farmacocinética , Estrona/sangre , Femenino , Humanos , Espectrometría de Masas , Persona de Mediana Edad
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