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M Posada

Publications and source records attributed to M Posada.

18 recordsLinked to original sources
PubMed2001

Automated strong cation exchange extraction of fatty acid esters of 3-(N-phenylamino)-1,2-propanediol from oil samples for routine quantification by HPLC-APCI/MS/MS.

Fatty acid esters of 3-(N-phenylamino)-1,2-propanediol are currently considered the best chemical markers of toxic oils related to the Spanish toxic oil syndrome. Recent research in this area has undertaken the exhaustive and quantitative characterization of these compounds in oils collected during the epidemic outbreak. Current methods developed in this laboratory are based on solid phase extraction (SPE) using SCX cartridges followed by HPLC-APCI/MS/MS quantification. To circumvent the long and tedious extraction procedure, the SPE protocol was adapted for automatic extraction and the problems derived from the use of the immiscible solvents required for the SCX extraction were solved. Linearity of the analytical method was found in the same range as for the manual method. Extraction recoveries were 87 and 75% for 2-hydroxy-3-(N-phenylamino)propyl linoleate and 2-(linoleyloxy)-3-(N-phenylamino)propyl linoleate, respectively, and the corresponding coefficients of variation were approximately 1%, greatly improving reproducibility over manual procedures.

Cation Exchange Resins↗
PubMed2000

DR2 antigens are associated with severity of disease in toxic oil syndrome (TOS).

Toxic oil syndrome (TOS) was an epidemic which broke out in Spain in 1981, caused by the ingestion of rapeseed oil denatured with 2% aniline and sold illegally as edible oil. More than 20,000 people were affected and mortality rate was 8.4%. Genetic susceptibility appears to be involved in the pathology of this disease. Several reports have described association between the chronic stage of the disease and DR-DQ antigens (DR3, DR4, DR2 and DQ8). In the present work, we have reassessed the HLA class II antigens in a well-designed case-control study. Triplets of subjects (n=265) composed by chronic patients (n=117), non-affected family members (n=71) and non-related controls (n=77) were studied. Also, HLA class II antigens were analyzed in patients who had died from TOS (n= 34) and in TOS control patients who died from other non-TOS related causes (n=13). Regarding surviving patients no significant association was found between HLA and disease. In contrast, an increase in phenotypic frequency of DR2 antigen, was found in patients who had died from TOS (73.5%) compared with the whole study group: TOS-affected alive patients (25.6%, corrected P<0.001), non-affected family members (28.5%, corrected P<0.001), non-related controls (23.9%, corrected P<0.001) and dead controls (38.4%, P=0.03).

Aniline Compounds↗
PubMed1999

Umbilical cord blood banking for unrelated transplantation: evaluation of cell separation and storage methods.

Cost-efficient umbilical cord blood (UCB) banking requires well-standardized methods of volume reduction and storage. To compare UCB fractionation using a technique of hydroxyethyl starch (HES) sedimentation with the Ficoll (double) and Percoll methods, 50 whole units was allocated randomly to each procedure. HES resulted in a significantly better recovery of mononuclear cells (87.5%), granulocyte/macrophage colony-forming units (CFU-GM) (88.4%), and CD34- cells (87.4%) and lesser volume reduction (85.5%). HES was the least laborious, time consuming, and expensive of the three procedures, costing 3.4- and 4.4-fold less than the Ficoll and Percoll methods, respectively. Five units processed by each method was frozen in 4.5-mL cryotubes under optimal conditions. After thawing, the greatest degree of recovery of viable nucleated cells and number of CFU-GM per unit were obtained using the HES procedure. Using 4.5-mL cryotubes, the calculated number of units that could be stored in 600-L containers was 3.8- and 2.2-fold higher for Ficoll- and Percoll-separated than for HES-separated units, respectively. Nevertheless, the higher direct costs of the density gradient separation procedures outweighed their lower storage cost. For long-term cryopreservation, we assessed the freezing of HES-processed units in 50-mL cryobags and their specifically designed canisters. We found cell recoveries similar to those obtained with cryotubes, but storage capacity was decreased. Special racks designed for these canisters resulted in a 5-fold increase over the number of units stored in standard cryobags. This system also is feasible for Percoll- and Ficoll-separated units, resulting in comparable storage costs for the three separation methods. We conclude that this HES procedure and the 50-mL cryobags constitute a cost-efficient system for large-scale UCB banking.

Blood Preservation↗
PubMed1998

Detection of maternal DNA in umbilical cord blood by polymerase chain reaction amplification of minisatellite sequences.

One of the concerns about the use of cord blood as a source of hematopoietic stem cells for allogeneic transplantation is the possibility of contamination by maternal cells which could cause life-threatening GVHD. We have assessed cord blood contamination using PCR analysis of several minisatellite regions to detect maternal DNA. Eighty mother-cord pairs were obtained for this study. In one case there were no specific maternal alleles at any loci and, therefore, cord blood could not be evaluated. Thus, there was a total of 79 informative cases for the detection of maternal cells in the fetal circulation. In most cases, the level of detection was between 0.5 and 1%. We detected maternal DNA in the cord blood sample in only one case (1.26%), and the analysis of dilution experiments led to an estimate of 0.5-1% maternal cells. In conclusion, using PCR amplification of hypervariable regions, maternal DNA is very rarely detected in the cord blood collected at birth, although this approach has a relatively low level of sensitivity.

Chimera↗
PubMed1997

Cytokine mRNA expression in lung tissue from toxic oil syndrome patients: a TH2 immunological mechanism.

In 1981, an epidemic occurred in Spain, toxic oil syndrome (TOS), in people who consumed rapeseed oil denatured with 2% aniline, and it was one of the largest intoxication epidemics ever recorded. In 1989, a similar disease, eosinophilia-myalgia syndrome (EMS) was reported in the USA and was associated with the ingestion of L-tryptophan. The pathologic findings in TOS showed primary endothelial injury, with cell proliferation and perivascular inflammatory infiltrates. Immunologic mechanisms have presumably been operative in the pathogenesis and perpetuation of TOS. Our previous findings pointed to a T-cell activation during acute phase of the disease. In order to analyze which T-cell subset is involved on TOS, we have developed an mRNA extraction procedure from paraffin-embedded lung tissues in patients with pulmonary involvement. We analyzed mRNA expression from different cytokines (IL-1, IL-2, IL-4, IL-5, IFN-gamma, GM-CSF) and CD25 (interleukin 2 receptor) and CD23 (low affinity IgE receptor), using RT-PCR technique. In lung tissues from these patients a T-cell activation was observed. We found a significant increase in Th1 (P = 0.006) and Th2 (P = 0.003) cytokine profile in TOS patients with respect to controls. The increment in TH2 response with respect to TH1 is significant (P = 0.03) in TOS lung specimens. Non-significant differences were obtained in other cytokines and receptors studied as IL-1, CD25, CD23 and GM-CSF. Data presented in this paper are the first clear evidence that an immunological mechanism is directly implicated in this illness.

Adolescent↗
PubMed1994

Immunological basis of toxic oil syndrome (TOS).

The toxic oil syndrome (TOS), a multisystemic disease, that occurred in Spain in 1981, was caused by the ingestion of rapeseed oil denatured with 2% aniline. Due to the clinical course of the disease, immunopathological mechanisms have been suspected but a direct connection was never demonstrated. To analyse this possibility, we determined several immunological parameters in the sera of patients with TOS and without the disease, using a case-control design: total immunoglobulins, IgG and IgE antibodies against different toxic agents (oleylanilide, aniline, linoleyl-anilide, and 3-phenylaminopropane-1-2-diol), autoantibodies, cytokines (IL-4, IL-6, TNF, GM-CSF) and soluble receptors (sCD23 and sIL-2R). We detected high levels of sIL-2R in TOS patients compared to controls (P < 0.0001). A higher levels of sCD23 and IgE were also found. In addition, the response to oleyl-anilide of peripheral blood lymphocytes from TOS patients was studied and a significant proliferative response in 30% of TOS patients versus 5% controls was observed. Our data support the implication of the immune system in the acute phase of TOS, with a possible activation of T-cells and release of cytokines, that could explain some of the clinical findings in this phase of the disease.

Anilides↗
PubMed1993

Toxic oil syndrome and eosinophilia-myalgia syndrome: May 8-10, 1991, World Health Organization meeting report.

In May 1991, researchers and clinicians from throughout the world met at a workshop sponsored by the Regional Office for Europe of the World Health Organization in collaboration with the Fondo de Investigación Sanitaria, Spain, and the U.S. Food and Drug Administration, National Institutes of Health, National Institutes of Mental Health, and Centers for Disease Control and Prevention to share information about two very similar diseases--toxic oil syndrome and eosinophilia-myalgia syndrome. In this paper the interpretation of conference proceedings is presented, current knowledge of the two disorders is summarized, and some possible areas for future research are mentioned. Toxic oil syndrome and eosinophilia-myalgia syndrome have many similarities. Both are related to consumer products that were presumed to be safe but have been found to have numerous trace contaminants, many of which remain to be identified, including the etiologic agents of both disorders. Both illnesses affect patients clinically by causing intense, incapacitating myalgias and a marked peripheral eosinophilia. Other rheumatologic manifestations are common in both, including arthralgias, sicca syndrome, scleroderma-like skin changes, carpal tunnel syndrome, and joint contractures. No clinical or laboratory feature has been found to be pathognomonic of either disease, and accurate diagnosis rests on the clinical judgment of the attending physician. Deaths have occurred in both diseases, and the cumulative mortality for each is approximately 2.5% for the first 2 years. Long-term complications include pulmonary hypertension, peripheral neuropathies, and joint contractures. Although treatment with corticosteroids has resulted in significant symptomatic relief in persons with either disorder, it does not alter the clinical course or long-term outcome. Research into the etiologic agents, preferred treatments, and ways to avoid similar problems in the future is needed.

Animals↗
PubMed1993

Analysis of polychlorinated dioxins and furans in samples of the toxic oil syndrome.

1 Polychlorinated dioxins (PCDDs) and furans (PCDFs) are known to produce a wide range of toxic effects. 2 PCDDs and PCDFs are typical contaminants of chlorinated phenols, and pentachlorophenol and related compounds have been shown to be widely distributed among selected oil samples taken from the 1981 Spanish toxic oil epidemic. 3 Six control and eight case oil samples were analysed using GC/MS for PCDDs and PCDFs. Only small concentrations, normally below 1 ng g-1, of the higher chlorinated PCDDs and PCDFs were detected. There were no statistical differences between the case and control oils. 4 These levels seem to be too low to elicit toxic effects, although they could be enough to potentiate the toxicity of other xenobiotics present in the oils. However, it is uncertain whether the levels of these compounds measured in 1990 reflect the levels present when the oils were consumed in 1981, or whether or not the levels measured in crude oils are representative of fried oils.

Brassica↗
PubMed1992

Construction of a genetically defined Salmonella typhi Ty2 aroA, aroC mutant for the engineering of a candidate oral typhoid-tetanus vaccine.

The construction of a Salmonella typhi Ty2 strain harbouring defined deletions in both the aroA and aroC genes is described. These deletions have been fully defined at the molecular level by DNA sequencing and have been introduced in such a way that no foreign DNA remains in the S. typhi genome. This strain is attenuated in mice when given by the intraperitoneal route suspended in hog gastric mucin and is attenuated to a similar level to strains harbouring deletions in aroA or aroC alone indicating that both lesions are capable of attenuating independently. We have used this defined S. typhi aroA aroC strain to express stably a non-toxic 50 kDa fragment of tetanus toxin (fragment C) from a gene incorporated into the chromosome. This strain has the advantage of harbouring no antibiotic-resistance markers and we consider it to be a candidate bivalent oral typhoid-tetanus vaccine.

Administration, Oral↗
PubMed1990

Participation of eosinophils in the toxic oil syndrome.

The participation of eosinophils in the Spanish toxic oil syndrome (TOS) was investigated. Eosinophil infiltration and degranulation in tissues from 52 patients with the TOS were examined by immunofluorescence staining for the eosinophil granule major basic protein (MBP). Serum MBP levels were determined in sera from 323 patients. Eosinophil infiltration and degranulation were found in several tissues, especially during the acute phase of the TOS, and serum MBP was significantly elevated during all phases of the disease, suggesting that eosinophils play a role in the pathogenesis of the TOS.

Blood Proteins↗
PubMed1987

Toxic-oil syndrome: case reports associated with the ITH oil refinery in Sevilla.

Toxic-oil syndrome (TOS), a new disease that occurred in epidemic form in Spain in 1981, has been associated with the ingestion of unlabelled oil bought principally from travelling salesmen. Chemical analysis of oils taken from ill families has shown them to consist of varying proportions of different vegetable oils and animal fats, often showing chemical evidence of prior treatment with aniline. We investigated the unusual circumstances surrounding the reported occurrence of three TOS cases in two families in Sevilla, a city located far away (approximately 300 km) from the group of 14 provinces in central and northwestern Spain where 99% of the TOS cases occurred. Each case we investigated fitted the clinical picture of TOS and was not consistent with any other diagnosis. Illness apparently occurred as a result of ingestion of oil taken from the ITH oil refinery in Sevilla, a plant in which rapeseed and grapeseed oils were refined for the distributing firm through which oil bearing the causative agent of TOS is thought to have entered the market. These data provide further strong support for the hypothesis that food oil was the vehicle by which the aetiological agent of TOS was transmitted. Because ingestion of refined denatured rapeseed oil was most closely associated with the illness in time, the TOS agent was probably contained initially in this type of oil. The agent very probably entered later oil mixtures through such contaminated rapeseed oil.

Adult↗
PubMedDate not supplied

[Review of ethical aspects in biomedical research. The experience of the Ethics Committee of the Center for Toxic Oil Syndrome and Rare Diseases [CISATER]].

This Field Note aims to make known the decisions taken by the Ethics Committee of the Instituto de Salud Carlos III for Toxic Oil Syndrome regarding the secondary use of research specimens in biological research when informed consent is lacking. This is a common concern in the field of biomedical research. After debating the ethical suitability of the secondary use of these samples, our main conclusion is that researchers conducting prospective studies should expressly solicit written informed consent from participants in the study about i) whether there will or could be any secondary use of the samples and, if so, ii) whether such secondary use would be conditional on the type of research.

Biomedical Research↗