Biomedical subjects

T Soriano

Publications and source records attributed to T Soriano.

6 recordsLinked to original sources

PubMed2001

Improved solid-phase extraction method for systematic toxicological analysis in biological fluids.

A method for the simultaneous qualitative and quantitative determination of drugs of abuse (opiates, cocaine, or amphetamines) and prescribed drugs (tricyclic antidepressants, phenotiazines, benzodiazepines, etc.) in biological fluids--blood, urine, bile, and gastric contents--was developed. This procedure involves solid-phase extraction with Bond-Elut Certify columns followed by analysis by gas chromatography-nitrogen-phosphorus detection (GC-NPD) and confirmation by gas chromatography-mass spectrometry (GC-MS), after derivatization, when necessary. Pretreatment was performed on all samples: sonication for 15 min plus enzymatic hydrolysis with beta-glucuronidase in urine. With respect to the internal standards, nalorphine and trihexylamine were used for basic substances, allobarbital for acidic drugs, and prazepam for benzodiazepines. Acidic and basic compounds were extracted from different aliquots of samples at different pH levels: 6-6.5 for the acidic and neutral and 8-8.5 for the basic and the benzodiazepines. Several areas of experimental design were considered in the process of method optimization. These included internal standards, pH, sonication, flow rate and washing solvents. It was found that systematic analysis could be reliably performed using optimized extraction conditions. The recovery rates for the compounds tested were always higher than 61.02%.

Adsorption↗

PubMed1996

Evaluation of new putative tumor markers for melanoma.

BACKGROUND: The early diagnosis of recurrent melanoma can contribute to better outcome if the disease can be surgically resected or if the metastases are responsive to systemic therapies. Lipid-associated sialic acid (LASA-P) and the S-100 protein (S-100) were evaluated as tumor markers for melanoma with the goal of early detection of recurrence. METHODS: Sixty-seven patients were identified who had levels of S-100 and LASA-P drawn during their clinical course. A multivariate regression analysis was performed to determine the significance of the serum markers in relation to other prognostic factors for melanoma. RESULTS: After a median follow-up of 30 months, 58 patients had recurrences, and 49 patients died of disease. LASA-P elevation was not associated with the time to recurrence (p = 0.2176) or survival (p = 0.2507). S-100 positivity was a significant predictor of recurrence (p < 0.0001) and survival (p = 0.0059). The median time to recurrence for S-100-positive and S-100-negative patients was 7.6 and 33.8 months, respectively. The median survival time was 59.2 months for S-100-negative patients and 29.6 months for patients positive for S-100. CONCLUSIONS: Serum S-100 shows significant correlations to both time to recurrence and survival and could be useful in the clinical detection of malignant melanoma.

Adult↗

PubMed1996

Method for the simultaneous quantification of n-hexane metabolites: application to n-hexane metabolism determination.

1. The described analytical procedure permits the simultaneous determination of the main n-hexane metabolites in urine. 2-Hexanone, 2-hexanol, 2, 5-hexanediol and 2, 5-hexanedione, were chosen to dose the rats used in this study. All urine samples were collected and analysed on a daily basis, before and after acidic hydrolysis (pH 0.1) by GC/MS. 2-Hexanone, 2, 5-dimethylfurane, gamma-valerolactone and 2, 5-hexanedione were determined before hydrolysis: 2-hexanol and 2, 5-hexanediol, after hydrolysis; and 5-hydroxy-2-hexanone and 4, 5-dihydroxy-2-hexanone were calculated by the difference between gamma-valerolactone and 2, 5-hexanedione with and without hydrolysis, respectively. 2. A metabolic scheme was proposed reflecting the biotransformations undergone by the four compounds assayed. We consider 2, 5-dimethylfurane as a "true metabolite' because the quantities detected were always greater before hydrolysis. 3. It has been reported that human and rat n-hexane metabolism follow a similar pattern. Therefore, as a practical application and without increasing either sample or time requirements, the simultaneous quantification of the different metabolites and their excretion profile could provide better information about the metabolic situation of exposed workers than the determination of 2, 5-hexanedione alone. According to our experimental results, 4, 5-dihydroxy-2-hexanone itself would be a good toxicity indicator.

Animals↗

PubMed1995

CD1-restricted T cell recognition of microbial lipoglycan antigens.

It has long been the paradigm that T cells recognize peptide antigens presented by major histocompatibility complex (MHC) molecules. However, nonpeptide antigens can be presented to T cells by human CD1b molecules, which are not encoded by the MHC. A major class of microbial antigens associated with pathogenicity are lipoglycans. It is shown here that human CD1b presents the defined mycobacterial lipoglycan lipoarabinomannan (LAM) to alpha beta T cell receptor-bearing lymphocytes. Presentation of these lipoglycan antigens required internalization and endosomal acidification. The T cell recognition required mannosides with alpha(1-->2) linkages and a phosphotidylinositol unit. T cells activated by LAM produced interferon gamma and were cytolytic. Thus, an important class of microbial molecules, the lipoglycans, is a part of the universe of foreign antigens recognized by human T cells.

Antigen Presentation↗

PubMed1986

Transient visual anomalies associated with drug treatment for spastic colon.

A case report revealing two previously unreported adverse side effects of meprobamate and tridihexethyl chloride (Milpath) drug therapy for a spastic colon is presented. The two previously unreported adverse effects are a diffuse loss of color discrimination and an increased time course to complete dark adaptation.

Colonic Diseases, Functional↗

PubMedDate not supplied

Rapid analysis of amphetamine, methamphetamine, MDA, and MDMA in urine using solid-phase microextraction, direct on-fiber derivatization, and analysis by GC-MS.

A rapid, sensitive, and solvent-free procedure for the simultaneous determination of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), and 3,4-methylenedioxymethamphetamine (MDMA) in urine was developed using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring mode. A headspace vial containing the urine sample, NaOH, NaCl, and amphetamine-d3 as the internal standard was heated at 100 degrees C for 20 min. A polydimethylsiloxane fiber was maintained in the vial headspace for 10 min in order to adsorb the amphetaminic compounds, which were subsequently derivatized by exposing the fiber to trifluoroacetic anhydride for 20 min in the headspace of another vial maintained at 60 degrees C for 20 min. The trifluoroacetyl derivatives were desorbed in the GC injection port for 5 min. Several parameters were considered during the method optimization process. These included a comparison of SPME with or without headspace, the required derivatization procedure, and the influence of temperature on the headspace extraction and derivatization methods. The optimized method was validated for the four compounds tested. Calibration curves showed linearity in the range 50-1000 ng/mL (r = 0.9946-0.9999). Recovery data were 71.89-103.24%. The quantitation limits were 10 ng/mL for amphetamine and methamphetamine and 20 ng/mL for MDA and MDMA. All of these data recommend the applicability of the method for use in the analytical routine of a forensic laboratory.

3,4-Methylenedioxyamphetamine↗