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Biomedical subjects

R Esparza

Publications and source records attributed to R Esparza.

10 recordsLinked to original sources
PubMed2006

Hypersensitivity to aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs).

Hypersensitivity to aspirin and other non steroidal anti-inflammatory drugs (NSAIDs) manifesting in the airways (rhinosinusitis, polyps, asthma) or in the skin (urticaria, angioedema) is the second most frequent untoward allergic reaction to drugs. Various aspects of this syndrome, such as its clinical features, the cell types and mediators involved, the role of underlying chronic inflammatory processes, the patterns of cross-reactivity between NSAIDs, the major role of sulfidoleukotrienes (LTC4) and of some other mediators such as prostaglandin E2 (PGE2) and C5a are briefly reviewed. It has been assumed for a long time that there were no reliable in vitro tests for that condition and that diagnostic confirmation can only be ascertained by provocation challenge. This appears no longer to be true, since several recent studies using a leukotriene release test (CAST) or a basophil activation test (BAT) on blood basophils, or a combination of both tests, yields positive results (70-75%) in a sizeable number of clinically validated cases, with a high specificity (above 85%). The finding in that syndrome of hyperreactive basophils suggests that the NSAID hypersensitivity syndrome is due to the associated effect of several factors: 1) Localized inflammatory processes causing a non specific cellular hyperreactivity; 2) An abnormal pharmacogenetic reaction to NSAIDs resulting in a hyperproduction of LTC4 and other mediators by activated mast cells, basophils and eosinophils.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

Preparation of AlFe nanoparticles by mechanical alloyed technique.

Small metallic particles (1-3 nm) have been obtained using mechanical alloying techniques. Analytical techniques such as scanning electron microscopy have been used for the morphological and chemical characterization of the AlFe alloyed powders. B, Ni and Ti have been explored as reinforced elements to the initial AlFe mixture. X-ray diffraction patterns and transmission electron microscopy (TEM) techniques have been employed for the structural characterization of the small metallic particles. Theoretical simulations based on molecular dynamics have been used to interpret some of the experimental structural results. Furthermore, theoretical simulations of HREM images based on the dynamical theory of electron diffraction have also been obtained and comparisons with the experimental results have been carried out. The complementary analyses determined that the produced clusters are basically AlFe alloyed nanoparticles immersed in a matrix and with multiple defected structures.

Aluminum↗
PubMed2005

Structure, stability and catalytic activity of chemically synthesized Pt, Au, and Au-Pt nanoparticles.

Small (1-5 nm) metallic nanoparticles of Pt, Au, and Au/Pt of different nominal compositions in colloidal form were synthesized by a chemical reduction method using polymer (PVP) as protecting agent. Analytical techniques like HREM and UV-vis spectroscopy have been used to characterize the morphology and structural properties of these small particles. Theoretical simulations based on molecular dynamical have been used to interpret the experimental structural results and analyze the macroscopic properties like stability and catalytic selectivity of these nanoparticles based on the morphology and atomic distribution in the clusters.

Catalysis↗
PubMed2004

The flow-cytometric determination of basophil activation induced by aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) is useful for in vitro diagnosis of the NSAID hypersensitivity syndrome.

BACKGROUND: Hypersensitivity reactions to non-steroidal anti-inflammatory drugs (NSAIDs), manifested by cutaneous symptoms and/or airway manifestations represent 20-25% of all hypersensitivity reactions to drugs. Today, it is still claimed that no in vitro diagnostic tests exist for that condition and that the only way to confirm the diagnosis is a provocation challenge. OBJECTIVE: The objective of this study was to assess whether NSAIDs may provoke blood basophil activation in vitro in such patients, as detected by a flowcytometric technique. METHODS: Sixty NSAID hypersensitive patients (38 with cutaneous, 20 with airway and two with cutaneous and airway symptoms) and 30 control patients (15 asthmatics) were selected. Their hypersensitivity was confirmed by documented history indicating at least two clinical episodes to two or more different NSAIDs or by positive oral provocation challenge. Isolated buffy coat leukocytes were stimulated in vitro with aspirin, paracetamol, metamizol, diclofenac, and naproxen. The percentage of activated basophils was evaluated by an anti-CD63. RESULTS: Aspirin showed a sensitivity of 43.3%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 99.4%. For the other NSAIDs, the sensitivity and specificity values were: for paracetamol 11.7% and 100%, for metamizol 15% and 100%, for diclofenac 43.3% and 93.3% and for naproxen 54.8% and 74.1%. When considering the first four NSAIDs, the global sensitivity raised to 63.3% and specificity to 93.3%. If the number of tests is to be limited for practical reasons, the combination of acetylsalicylic acid and diclofenac at two concentrations yields a sensitivity of 58.3% and a specificity of 93.3%. CONCLUSIONS: Flowcytometric determinations of basophil activation following stimulation with NSAIDs show a high sensitivity (60-70%) with specificity above 90%. So this test may help avoiding some cumbersome and dangerous provocation challenges.

Acetaminophen↗
PubMed2004

Basophil activation and sulfidoleukotriene production in patients with immediate allergy to betalactam antibiotics and negative skin tests.

BACKGROUND: New in vitro diagnostic methods for IgE-mediated drug allergic reactions, such as basophil activation test and antigen specific sulfidoleukotriene test, have proven their usefulness in patients with positive skin tests. OBJECTIVE: To assess the usefulness of basophil activation test and antigen specific sulfidoleukotriene test in the diagnosis of patients with IgE-mediated allergy to Betalactam antibiotics and negative skin tests. METHODS: The 23 patients included in the study underwent basophil activation test, antigen specific sulfidoleukotriene test and specific IgE. The patients were classified into three groups. GROUP A: patients with positive specific IgE. GROUP B: patients with a unique immediate reaction to Betalactams, negative specific IgE and positive oral provocation tests. And Group C: patients with at least two immediate reactions induced by Betalactams and negative specific IgE. RESULTS: The sensitivity/specificity of the different tests are: basophil activation test 39.1 %/93.3%, antigen specific sulfidoleukotriene test 22.7%/83.3%, specific IgE 21.7%/86.7%. The joint use of the three tests allows diagnosis of 60.9% of the patients. CONCLUSION: In vitro diagnostic tests, especially basophil activation test, are very important tools in the diagnosis of patients with IgE-mediated allergy to Betalactams and negative skin tests, avoiding performance of potentially dangerous oral provocation tests in a high percentage of cases.

Adult↗
PubMed2001

Renal functional reserve in patients with recently diagnosed Type 2 diabetes mellitus with and without microalbuminuria.

BACKGROUND/AIMS: During the first 10 years, two thirds of the patients with type 2 diabetes mellitus (DM) have microalbuminuria (MA). Functional renal reserve (FRR) and its relationship with proteinuria and metabolic control are unknown at the early phases of disease. We investigated the frequency of MA in recently diagnosed type 2 DM patients, and its association with FRR. METHODS: We studied 181 type 2 DM patients with less than 6 months since diagnosis. Renal volume, MA, glomerular filtration rate (GFR) and renal plasma flow (ERPF) were evaluated before and after an acute oral protein load in 28 type 2 DM patients (14 with, and 14 without MA), and in 7 healthy subjects. RESULTS: A total of 10.6% of the patients had MA. MA patients had higher cholesterol and triglyceride levels than those normoalbuminuric. Twenty recently diagnosed type 2 diabetic patients showed high basal GFR. Twelve of them had MA and insulin resistance. After the acute oral protein load, the control subjects and the patients without MA increased their GFR and their ERPF. The group with MA did not. CONCLUSIONS: Seventy-five percent of the patients were hyperfiltering. Normoalbuminuric patients had larger increase in GFR and ERRPF than MB patients. We conclude that FRR measurement can be an important tool for the diagnosis of latent diabetic nephropathy.

Adult↗
PubMed1995

The epidemiology of tuberculosis in Gran Canaria, Canary Islands, 1988-92: effectiveness of control measures.

SETTING: Since there is no national programme for tuberculosis control in Spain and the epidemiological situation in this country is unknown, a programme against tuberculosis in Gran Canaria (Canary Islands) was started in 1987. OBJECTIVE: To analyze the impact of this control programme, particularly the trend of new cases of tuberculosis by age groups and risk factors for 1988-92. DESIGN: A detailed search of all new cases of tuberculosis was carried out by examining the files of all public and private hospitals and outpatient clinics of the island, the records of the Services of Clinical Microbiology and Pathology of the public hospitals, and the registers of patients with AIDS. RESULTS: The annual rates of new cases of tuberculosis per 100,000 were 32.2 in 1988 (214 cases), 26.2 in 1990 (174 cases), and 29.4 in 1992 (196 cases), and the rates of sputum-positive cases 13.3 (89 cases), 12 (80 cases) and 15 (100 cases), respectively. The distribution of tuberculosis cases by age peaked in the age groups 40-49 and 30-39 years. Between 1988 and 1992, statistically significant differences were found in the percentage of cured patients (21% [45/214] vs 85.7% [168/196]), patients with a delay in diagnosis > 3 months (40.2% [86/214] vs 21.9% [43/196]), and contacts evaluated (45.3% [97/214] vs 90.3% [177/196]). However, an upward trend in the incidence of tuberculosis for 1990-92 was found in association with an increase of new cases among the homeless, immigrants, and HIV-infected people. When these three population groups were excluded from the analysis, the annual rate for the total population showed a progressive decline from 1988-92. CONCLUSIONS: The data studied here show that successful priority control measures (cure rate, early diagnosis, study of contacts) have been achieved in this island. It is necessary, however, to develop strategies for combating the tuberculosis problem in specific high risk populations.

Adolescent↗
PubMedDate not supplied

Accuracy of combined clinical findings and fine needle aspiration cytology for the diagnosis in palpable breast tumors.

OBJECTIVE: A prospective study to evaluate the confidence level and predictive value of the fine needle aspiration biopsy was performed in the Oncology Service, "Hospital 20 de Noviembre, ISSSTE", Mexico City. MATERIAL AND METHODS: The cases with a palpable breast tumor, histologically confirmed who presented from 1992 to 1994 were included. One aspirate was done in each patient and these were reviewed by the same pathologist. We determined sensitivity, specificity and predictive value of the test. Age, border characteristics, size and mobility of the tumor were evaluated by Bayesian analysis. RESULTS: From 213 aspirates, 199 were elegible for diagnosis, 98 (46%) had a diagnosis of carcinoma, 13 were acellular and one suggestive. The acellular diagnoses were considered negative and suggestive positive, for analysis purposes. Mean age and tumor size were: 46.6 years (range 14-90) and 3.7 cm. (range 1-13) respectively. Sensitivity (0.932), specificity (0.973) and positive predictive value (96.9%) were estimated. We observed a high probability of true positive [P(D+/T+)] > 0.8 results in patients between 40 and 60 years of age, irregular borders, size > 2 cm and fixed lesions. CONCLUSIONS: The test has a high confidence level and in presence of two or more of the clinical factors mentioned, definitive decisions regarding treatment could be taken, without need of histologic confirmation.

Adolescent↗
PubMedDate not supplied

Nasal candidiasis in an immunocompetent patient.

We report a case of nasal candidiasis in an immunocompetent host who denied the use of topical or systemic corticosteroids. The patient was treated with itraconazole 100 mg. with resolution of the symptoms.

Adult↗