Biomedical subjects

Elena Almarza

Publications and source records attributed to Elena Almarza.

7 recordsLinked to original sources

PubMed2006

PARP-2 deficiency affects the survival of CD4+CD8+ double-positive thymocytes.

Poly-(ADP-ribose) polymerase-2 (PARP-2) belongs to a large family of enzymes that synthesize and transfer ADP-ribose polymers to acceptor proteins, modifying their functional properties. PARP-2-deficient (Parp-2-/-) cells, similar to Parp-1-/- cells, are sensitive to both ionizing radiation and alkylating agents. Here we show that inactivation of mouse Parp-2, but not Parp-1, produced a two-fold reduction in CD4+CD8+ double-positive (DP) thymocytes associated with decreased DP cell survival. Microarray analyses revealed increased expression of the proapoptotic Bcl-2 family member Noxa in Parp-2-/- DP thymocytes compared to littermate controls. In addition, DP thymocytes from Parp-2-/- have a reduced expression of T-cell receptor (TCR)alpha and a skewed repertoire of TCRalpha toward the 5' Jalpha segments. Our results show that in the absence of PARP-2, the survival of DP thymocytes undergoing TCRalpha recombination is compromised despite normal amounts of Bcl-xL. These data suggest a novel role for PARP-2 as an important mediator of T-cell survival during thymopoiesis by preventing the activation of DNA damage-dependent apoptotic response during the multiple rounds of TCRalpha rearrangements preceding a positively selected TCR.

Animals↗

PubMed2006

Anesthesiologist suicide with atracurium.

Atracurium is a nondepolarizing skeletal muscle relaxant used to facilitate endotracheal intubation and to induce skeletal muscle relaxation during surgery or mechanical ventilation. The drug undergoes a spontaneous non-enzymatic biotransformation, yielding laudanosine and an acrylate moiety. This report documents the case of a 45-year-old anesthesiologist who was found dead at the hospital where he worked. The victim was known to be depressed and undergoing treatment with venlafaxine. An empty syringe was found near the body. Toxicological analysis revealed the presence of laudanosine in the syringe, 0.6 mg/L of laudanosine in heart blood, 0.3 mg/L in urine, and 0.02 mg/L in vitreous humor. Meanwhile, concentrations of venlafaxine and O-desmethyl-venlafaxine, its active metabolite, were 0.7 and 1.1 mg/L in heart blood, 1.7 and 5.2 mg/L in urine, 0.5 and 0.7 mg/L in vitreous humor, and 400 and 20 mg in gastric content, respectively. All drugs and metabolites involved in the case were detected using gas chromatography with nitrogen-phosphorus detection (GC-NPD) and confirmed using GC-mass spectrometry in full scan mode after solid-phase extraction using Bond-Elut Certify columns. Additional high-performance liquid chromatography coupled to diode-array detection screening also obtained the same results. Quantitation of laudanosine and venlafaxine together with its metabolite was carried out using GC-NPD. No other drugs, including ethanol, were detected. Recoveries for laudanosine and venlafaxine were 89% and 86%, respectively, at 0.5 mg/L; intraday and interday precisions were 2% and 6%, and 3% and 7%, respectively; and limits of detection and quantitation were 6 and 20 ng/mL and 18 and 59 ng/mL, respectively. The linearity of the blood calibration curves was excellent for both drugs with r(2) values of > 0.999 (range 0.1-2.0 mg/L). Based on the autopsy findings, case history, and toxicology results, the forensic pathologists ruled that the cause of death was an overdose of atracurium, and the manner of death was suicide.

Anesthesiology↗

PubMed2005

Determination of several psychiatric drugs in whole blood using capillary gas-liquid chromatography with nitrogen phosphorus detection: comparison of two solid phase extraction procedures.

A simple and reliable gas chromatographic method with nitrogen-phosphorus detection without derivatization was developed for the detection of several psychiatric drugs in whole blood as part of systematic toxicological analyses (STA). Drugs included mirtazapine, chlorpromazine, methotrimeprazine (levomepromazine), clothiapine, olanzapine, clozapine, haloperidol, and thioridazine. All drugs were studied at concentrations of 100-2,000 microg/L, except haloperidol that was studied at concentrations of 400-8,000 microg/L. In order to select the best blood purification procedure and therefore increase the signal to noise ratio we have compared two solid-phase extraction (SPE) columns, Chem Elut and Bond Elut Certify, for their recovery, precision, sensitivity and matrix purification efficiency. Recoveries for these drugs using Chem Elut columns at 500 and 2,000 microg/L (2,000 and 8,000 microg/L for haloperidol) were in the range 21-65%, with intra-assay and inter-assay precisions of less than 17% and 19%, respectively. Limits of detection (LODs) and limits of quantitation (LOQs) for mirtazapine, chlorpromazine, methotrimeprazine, clothiapine, olanzapine, clozapine, and thioridazine ranged from 62 to 161 microg/L and from 205 to 531 microg/L, respectively. LOD and LOQ for haloperidol were 442 and 1,458 microg/L, respectively. Recoveries of these compounds using Bond Elut Certify columns at 500 and 2,000 microg/L (2,000 and 8,000 microg/L for haloperidol) were in the range 44-97%, with intra-assay and inter-assay precisions of less than 7% and 14%, respectively. LODs and LOQs for mirtazapine, chlorpromazine, methotrimeprazine, clothiapine, olanzapine, clozapine, and thioridazine ranged from 37 to 66 microg/L and from 122 to 218 microg/L, respectively. LOD and LOQ for haloperidol were 156 and 515 microg/L, respectively. Linearity was observed in the studied range for all compounds with r(2) values of >0.999. The use of the mixed-mode bonded-silica Bond Elut Certify columns showed advantages comparing with Chem Elut columns for the screening of these psychotropic agents such as higher recoveries, cleaner extracts, better sensitivity, better precision and less solvent consumption and subsequent disposal.

Adult↗

PubMed2004

Regulatory elements of the vav gene drive transgene expression in hematopoietic stem cells from adult mice.

OBJECTIVE: Previous studies have shown that the HS21/45 promoter of the vav protooncogene drives a predominant expression of exogenous transgenes in mouse hematopoietic cells, including clonogenic bone marrow (BM) progenitors. We investigated the activity of this promoter in the hematopoietic stem cell compartment of adult mice. MATERIALS AND METHODS: Inbred Ly5.1 transgenic mice expressing a nonfunctional human CD4 marker gene (hCD4) under the control of the HS21/45 promoter were generated. BM cells from these animals were sorted based on the intensity of hCD4 expression. Fractions characterized by high, intermediate, or low/negative expression of the transgene were then assessed for their competitive repopulation ability (CRA), using unfractionated BM cells from Ly5.2 mice as a reference competitor population. RESULTS: Data showed that BM cells having a low/negative or intermediate expression of hCD4 had a very poor hematopoietic CRA. In contrast, BM cells with high hCD4 expression were characterized by a high CRA. These observations were confirmed in the short- and long-term posttransplantation of primary and secondary recipients when analyzing the lymphoid and myeloid cells of recipient mice. CONCLUSIONS: Our results demonstrate for the first time that the regulatory HS21/45 sequence of the vav gene constitutes an efficient promoter for driving transgene expression in multipotent hematopoietic stem cells residing in the BM of adult mice. Thus, this promoter is proposed for the development of transgenic mice and gene therapy vectors that require restricted expression of exogenous transgenes in cells of the hematopoietic system, including primitive hematopoietic stem cells.

Animals↗

PubMed2004

A comparative solid-phase extraction study for the simultaneous determination of fluvoxamine, mianserin, doxepin, citalopram, paroxetine, and etoperidone in whole blood by capillary gas-liquid chromatography with nitrogen-phosphorus detection.

This paper reports a simple and reliable gas chromatographic method with nitrogen-phosphorus detection without derivatization for the simultaneous detection of fluvoxamine, mianserin, doxepin, citalopram, paroxetine, and etoperidone in whole blood as part of a systematic toxicological analysis (STA). All drugs were studied at concentration levels of 100-2000 ng/mL, except paroxetine for which it was necessary to study at concentration levels of 400-8000 ng/mL. A comparative and validation study using two solid-phase extraction (SPE) columns, Chem Elut and Bond Elut Certify, was developed regarding their recovery, precision, sensitivity, and matrix purification efficiency. The Chem Elut columns, diatomaceous earth, are closely related to conventional liquid-liquid extraction. The Bond Elut Certify columns, more recently developed in the market, are mixed SPE (reversed-phase and cation exchange sorbent). Recoveries for the antidepressants using Chem Elut columns at 500 ng/mL (2000 ng/mL for paroxetine) were in the range 43-72% with intra- and interassay precisions of less than 10% and 16%, respectively. Limits of detection (LODs) and quantitation (LOQs) for fluvoxamine, mianserin, doxepin, citalopram, and etoperidone ranged from 18 to 236 ng/mL and 60 to 786 ng/mL, respectively. LOD and LOQ for paroxetine were 303 and 1009 ng/mL, respectively. Recoveries of these compounds using Bond Elut Certify columns at 500 ng/mL (2000 ng/mL for paroxetine) were in the range 52-83% with intra- and interassay precisions of less than 6% and 8%, respectively. LODs and LOQs for fluvoxamine, mianserin, doxepin, citalopram, and etoperidone ranged from 7 to 28 ng/mL and 23 to 93 ng/mL, respectively. LOD and LOQ for paroxetine were 113 and 376 ng/mL, respectively. An excellent linearity was observed with both procedures from the LOQs up to the upper studied concentration level. In general, higher recoveries, cleaner extracts, better sensitivity, better precision, and reduced solvent consumption and disposal were achieved for the screening of these antidepressants with the use of the mixed SPE Bond Elut Certify compared with Chem Elut columns. The application of these methods on a forensic case study is also presented.

Aged↗

PubMed2004

Attempted suicide by ingestion of chlorpyrifos: identification in serum and gastric content by GC-FID/GC-MS.

A mild case of self-poisoning with a chlorpyrifos formulation following oral ingestion is reported. A 15-year-old female went to the emergency room after the ingestion of a product from a bottle marked with a label "Poison". On admission, she was obtunded, with normal vital signs and a strong smell of solvent. Therapeutic measures included the application of decontamination procedures, oxygen, and gastric protectors. She had a good outcome with mild CNS depression and bradycardia. Two hours after ingestion, biological samples were collected in the emergency room and sent for analysis to our laboratory with instructions to investigate the presence of solvents. The serum and gastric content contained 5.3 and 9.4 microg/mL of unmetabolized chlorpyrifos, 4.6 and 6.9 microg/mL of toluene, and 2.5 and 7.9 microg/mL of butyl acetate, respectively. Small traces of other solvents and tetradifon were also detected. Toxicological analyses were negative for ethanol, other volatile solvents, and common drugs of abuse. The simultaneous determination of chlorpyrifos, toluene, and butyl acetate was performed using the combination of gas chromatography (GC)-flame ionization detection for screening analysis and GC-mass spectrometry for confirmation of the obtained results. The method provides an excellent and rapid tool for use in cases of pesticide poisonings, allowing the simultaneous detection of the pesticide and distillates in the performance of systematic toxicological analysis in forensic and clinical laboratories.

Adolescent↗

PubMedDate not supplied

Investigation of a fatality due to trazodone poisoning: case report and literature review.

Trazodone is an antidepressant agent used in Spain since 1975. There are few documented reports of fatalities solely attributed to trazodone and none in which the main metabolite is analyzed. A fatal case of self-poisoning following oral ingestion is reported along with a description of the validated analytical methods involved, a discussion of poisoning characteristics, and a review of reports describing trazodone overdose cases with analytical results. The deceased was an 86-year-old man with cancer, who suffered depression. He went to see his doctor in a primary health care unit and told him he had just taken an unknown amount of tablets of Deprax to commit suicide. The doctor induced emesis as a first emergency measure. His death occurred before arriving to the hospital, and he left a suicide note nearby. Systematic toxicological analysis of postmortem blood used routinely in our laboratory revealed the presence of trazodone 4.9 mg/L and m-chlorophenyl-piperazine (m-CPP) 0.6 mg/L, its active and major metabolite. In addition, metamizol 19.6 mg/L and 4-methyl-amino-antipyrine (4-MAA) 40.7 mg/L, its active metabolite, were also found in blood. All drugs and metabolites involved in the case were detected using gas chromatography-nitrogen-phosphorus detection (GC-NPD) and confirmed using gas chromatography-mass spectrometry (GC-MS) mode total ion chromatogram. An additional high-performance liquid chromatography-diode array detection (HPLC-DAD) screening also obtained the same results. Quantitation of trazodone together with its metabolite in blood was carried out using GC-NPD, while quantitation of metamizol was performed using HPLC-DAD. Limits of detection for trazodone and m-CPP were 33 and 11 microg/L, respectively, absolute recoveries were more than 86% and 75%, respectively, intra-assay precisions less than 4%, interassay precisions less than 5%, and linearity up to 2.0 mg/L. Limit of detection for metamizol was 1117 microg/L, absolute recovery more than 84%, intra-assay precision less than 8%, interassay precision less than 12%, and linearity up to 48 mg/L. Based on the autopsy findings, patient history, toxicology results, and previously reported trazodone intoxications, the forensic pathologists ruled that the cause of death was due to an overdose of trazodone, and the manner of death was listed as suicide.

Aged↗