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C Vidal

Publications and source records attributed to C Vidal.

At least 73 records · Page 4Linked to original sources
PubMed1998

Structural elucidation by electrospray mass spectrometry: an approach to the in vitro metabolism of the macrolide immunosuppressant SDZ RAD.

SDZ RAD [40-O-(2-hydroxyethyl)rapamycin] is a macrolide immunosuppressant that is currently under clinical investigation after organ transplantation. The elucidation of its metabolic pathway is essential to improve the understanding of its therapeutic potentials and safety. In this article we describe investigations on the structural identification of some major metabolites of the drug produced by human liver microsomes in vitro. The principles described may be generally applicable for the structural elucidation of complex compound mixtures in biological matrices. Under the conditions of electron impact ionization, SDZ RAD undergoes extensive fragmentation and no information sufficient for structural elucidation is obtained. Therefore, mass spectrometry based on soft electrospray ionization (ESI) in conjunction with collision-induced fragmentation was the method of choice. High-performance liquid chromatography coupled to an ESI mass spectrometer resulted in separation and identification of 16-O-demethyl-SDZ RAD, the ring-opened form of SDZ RAD, and its dehydrate. Additionally, we characterized several demethylated and hydroxylated metabolites.

Chromatography, High Pressure Liquid↗
PubMed1998

Nonpigmenting fixed drug eruption due to pseudoephedrine.

BACKGROUND: The nonpigmenting fixed drug eruption is a distinctive drug reaction characterized by large, tender and symmetric erythematous plaques that disappear with no residual pigmentation. METHODS: A case of a non-pigmenting fixed drug eruption due to pseudoephedrine is reported. RESULT: The reappearance of typical lesions at the same sites after oral challenge with 60 mg pseudoephedrine together with the absence of pigmentation confirm the diagnosis. CONCLUSION: A new case of proven nonpigmenting fixed drug eruption to pseudoephedrine is described.

Adult↗
PubMed1998

Pericardial fluid postmortem: Comparative study of natural and violent deaths.

Thanatochemistry is an increasingly important ancillary procedure in forensic practice. Alterations are known to take place in biochemical components during the postmortem period, particularly in the blood, and both research results and their interpretation have been the object of some controversy. For that reason, emphasis has been placed on the examination of fluids that are neither altered nor contaminated as rapidly as blood after death. This study tested the hypothesis that pericardial fluid (PF) may be a suitable medium for biochemical analysis in corpses. The study sought to determine concentrations of urea, creatinine, glucose, creatinine kinase 2, proteins, calcium, sodium, and potassium, in the pericardial fluid of corpses. The study sample was divided into two groups, natural deaths and violent deaths. Intergroup results were compared, using Mann-Whitney's U test for paired data. No significant differences were obtained between the natural death and violent death groups for the parameters studied, with the exception of urea (p < .05). Further studies are required to compare these results and create the possibility for new conclusions.

Autopsy↗
PubMed1998

Occupational allergy caused by Dianthus caryophillus, Gypsophila paniculata, and Lilium longiflorum.

BACKGROUND: Occupational allergy to ornamental flowers is seldom reported. METHODS: We report a case of a 35-year-old male flower supplier who developed IgE-mediated allergic rhinoconjunctivitis with nasal polyps, and contact urticaria and dermatitis after handling Gypsophila paniculata. Dianthus caryophillus, and Lilium longiflorum. RESULTS: Studies revealed the presence of positive immediate skin prick tests. Rubbing tests were positive to G. paniculata and D. caryophillus. Serum specific IgE was detected against G. paniculata and L., longiflorum. In IgE immunoblot, two IgE-binding bands (15 and 17 kDa) were obtained against D. caryophillus, and two different bands (19 and 22 kDa) were visible against L. longiflorum. CONCLUSIONS: These findings suggest an IgE-mediated reaction as the mechanism responsible for the respiratory and cutaneous symptoms of the patient. No similar cases of allergy to D. caryophillus and L. longiflorum have been previously reported.

Adult↗
PubMed1998

Automated simultaneous quantification of the immunosuppressants 40-O-(2-hydroxyethyl) rapamycin and cyclosporine in blood with electrospray-mass spectrometric detection.

A new analytical method to quantify 40-O-(2-hydroxyethyl)rapamycin (SDZ RAD) and cyclosporine (Cs) simultaneously in blood is presented. The combination of an on-line solid-phase extraction step with an HPLC system coupled to an electrospray mass spectrometer gave excellent specificity, sensitivity, and reproducibility. Aliquots of deproteinized blood samples were injected into the HPLC system and extracted on-line, using a conventional C18 guard column. The extract was eluted from the guard column in the backflush mode and injected into the liquid chromatography-mass spectrometry system. The calibration functions for SDZ RAD and Cs extracted from blood with added analyte were linear from 0.15 to 30 microg/L (r2 = 0.999) and from 1.5 to 1000 microg/L (r2 = 0.999), respectively. The CVs of peak areas were 6.2% at 10 microg/L SDZ RAD (n = 6) and 6.2% at 100 microg/L Cs (n = 6). Recovery ranged from 84.3% to 102.3% for SDZ RAD and from 81.7% to 92.2% for Cs. The lower limit of detection for both drugs was 0.05 microg/L. A rate of four samples per hour was maintained during the consecutive analysis of SDZ RAD and Cs in >500 blood samples with one single extraction and analytical column. The method described is a powerful tool for the simultaneous determination of SDZ RAD and Cs in blood. It works without time-consuming sample preparation steps and with excellent reproducibility. Because of the detection performance of electrospray mass spectrometry, this system offers flexibility in the working range, which is essential for therapeutic drug monitoring under different conditions.

Chromatography, High Pressure Liquid↗
PubMed1998

[Stroke: a stranger among the people].

INTRODUCTION: Lack of awareness of warning signs of stroke is a factor that contribute to late patient arrival to the emergency department. OBJECTIVE: The goal of this pilot study was to determine the baseline knowledge of stroke among the population (terminology, signs-symptoms, risk factors and attitude) prior to educational campaigns. PATIENTS AND METHODS: A population-based interview using closed-ended questions was conducted by neurologists among 100 users of the Vall d'Hebron's Primary Health Center, randomly sampled. RESULTS: In our population a 9% unknowns totally the disease, of the remainder, 42% has a good knowledge of signs-symptoms and 46% of risk factors. Only 22% of the sample has good global knowledge of the disease. If suffering a stroke this population should seek medical attention through 911 (46.2%) or come directly to the emergency department (50.5%). If symptoms were gone away, transient ischemic attack (TIA), appears a trend to contact primary physicians (59.3%). Respondents aged > 65 years were less likely to recognize symptoms (p = 0.001) and to consider stroke as an emergency. Respondents with an affected relative (50.5%) tend to locate more exactly the disease at the brain (p = 0.05) and to arrive earlier to the emergency department (p = 0.045), than those with non-affected relatives. CONCLUSIONS: Less than a quarter of our population have a good knowledge of the disease. Stroke is considered an emergency unlike TIA. The information about stroke is theoretically associated with early presentation to the emergency department. These results permit a redesign of the questionnaire to conduct a second phase of the study and generalize them for the Spanish population.

Adolescent↗
PubMed1997

Radiographic visualization of patellar tendon grafts for the reconstruction of the anterior cruciate ligament.

The new biodegradable interference screws offer very many advantages for anterior cruciate ligament replacement with patellar tendon. However, their radiolucency makes it impossible to identify the anchorage sites. We describe an imaging technique of the plasty and its anchorage sites by means of a radiopaque contrast that is commonly used in radiology (Iopamidol; Bracco, Milan, Italy). It is an easy technique that does not extend the time of surgery, it is harmless, and allows us to identify malpositioning or impingement of the plasty.

Anterior Cruciate Ligament↗
PubMed1997

Paracetamol (acetaminophen) hypersensitivity.

BACKGROUND: Paracetamol (acetaminophen) intolerance can occur in less than 5% of aspirin-sensitive subjects as a result of inhibition of prostaglandin synthesis but hypersensitivity to paracetamol without aspirin sensitivity is rare. METHODS: We report a case of an acute life-threatening hypersensitivity reaction to paracetamol. RESULTS: An oral challenge with 125 mg of paracetamol was carried out and followed by generalized anaphylactic reaction. An oral provocation test with 500 mg aspirin was well tolerated in the patient. CONCLUSION: An acute hypersensitivity reaction to paracetamol is described in this study. The results of the study suggest a real allergic mechanism rather than inhibition of prostaglandin synthesis as responsible.

Acetaminophen↗
PubMed1997

Unsuspected sources of soybean exposure.

BACKGROUND: Hidden allergens in processed foods can provoke severe allergic reactions in sensitive individuals. The presence of soy proteins in typical Spanish sausage products (chorizo, salchichón, mortadella, and boiled ham), doughnut and soup stock cubes has not been reported previously. METHODS: The present article reports two examples of severe allergic reactions due to the ingestion of foods that unexpectedly contained soybean proteins. Allergollogic study included skin prick tests with the implicated foods and their components, serum specific IgE and bronchial and oral provocation tests. RESULTS: Skin test, serum-specific IgE, and bronchial and oral challenge tests (the latter, in one patient) were positive against soy and the above mentioned processed foods in which the presence of soybean flour was confirmed. CONCLUSIONS: This report demonstrates the importance of hidden allergens in allergic reactions to foods and the need to scrutinize closely every food component.

Adult↗
PubMed1997

Viral load in asymptomatic patients with CD4+ lymphocyte counts above 500 x 10(6)/l.

BACKGROUND: HIV-1-infected patients with a CD4+ lymphocyte count > or = 500 x 10(6)/l may be selected for antiretroviral treatment when viral load is above a given cut-off point. OBJECTIVES: To assess the stability of viral load measurement at CD4+ T-cell counts above 500 x 10(6)/l, and the proportion of patients selected for treatment if a cut-off point of 10,000 or 30,000 RNA copies/ml is used. DESIGN AND METHODS: Seventy-eight consecutive asymptomatic antiretroviral-naive HIV-1-infected patients with CD4+ lymphocyte counts > or = 500 x 10(6)/l, presenting for previously scheduled medical visits as outpatients, were enrolled. None of the patients had suffered from symptomatic primary infection or seroconverted within 6 months before enrollment. Two blood samples separated by a 1-month interval [day -30 (screening) and day 0 (enrollment)] were collected in an EDTA tube. Plasma was separated and frozen at -70 degrees C within 4 h of collection. HIV-1 RNA was quantified by polymerase chain reaction. CD4+ T cells were measured by flow cytometry. RESULTS: Viral load was fairly stable, and only four (13%) out of 30 pairs had a variation > or = 0.5 log10. At day -30 and day 0, log10 HIV RNA levels (mean +/- SD) were 4.24 +/- 0.7 and 4.35 +/- 0.87 log10 copies/ml plasma (P = 0.23). The difference of the mean was -0.11 (95% confidence interval, -0.28 to 0.07). At day 0 (n = 78) mean +/- SD value was 35730 +/- 73700 RNA copies/ml (range, < 200-438480; median, 9331; 25th and 75th percentiles, 1518 and 37193, respectively). In 13 patients (16%) the viral load was < 2000 copies RNA/ml. Seven out of 10 patients, who fulfilled the criteria of long-term non-progressors (LTNP), had viral load > 10,000 RNA copies/ml, and two patients had > 30,000 RNA copies/ml. Only two of the 13 patients with CD4+ T-cell counts > 750 x 10(6)/l had viral load > 10,000 copies/ml. CONCLUSIONS: A single-point viral load assessment is enough in asymptomatic patients with CD4+ lymphocytes counts > or = 500 x 10(6)/l since plasma HIV RNA measurements obtained 1 month apart are fairly stable. Approximately 25% of these patients (including some patients with LTNP criteria) will be selected for treatment if 30,000 RNA copies/ml is used as cut-off point, and approximately 50% if the cut-off point is 10,000 RNA copies/ml. Viral load > or = 10,000 is very unusual in patients with CD4+ T-cell counts > 750 x 10(6)/l.

Adult↗
PubMed1997

[Disability in the private pension system in Chile].

BACKGROUND: The degree of disability of workers ascribed to the private allowances system in Chile, is judged by Medical Commissions that apply norms that establish percentages of incapacity, without considering prognosis. AIM: To communicate the causes of disability among Chilean workers ascribed to the private allowances system, their mortality and to correlate the causes of death with diagnoses. SUBJECTS AND METHODS: We analyzed 13,456 consecutive cases judged between August 1990 and April 1992. Mortality was registered up to 12 months after judgment. RESULTS: Total incapacity was determined in 4,158 cases (30.9%), partial incapacity in 1,340 (9.9%) and minor incapacity in 7,958 (59.1%). Osteoarticular diseases were the main cause of disability in 4,460 patients (33.1%) and 77.8% of patients with malignant tumors were considered as having total incapacity. Mortality was 17% among subjects with total incapacity, 1.5% among those with partial disability and 1% among those with minor disability. The cause of death was related to the main disabling disease in 94% of subjects with total incapacity and 66.6% of those with partial incapacity. CONCLUSIONS: Osteoarticular diseases are the main cause of inability among workers ascribed to a private pension system.

Chile↗