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M J Alvarez

Publications and source records attributed to M J Alvarez.

At least 19 recordsLinked to original sources
PubMed2001

Oilseed rape flour: another allergen causing occupational asthma among farmers.

BACKGROUND: Farmers are exposed to a wide variety of sensitizers. Since occupational asthma (OA) can lead to permanent disability, exposure discontinuation is the preferred treatment. When this is not possible, the identification of the causative allergen may allow an alternative therapy. METHODS: We present three farmers diagnosed with OA as a consequence of handling fodder. We carried out skin tests with common and occupational allergens and with oilseed rape (OSR) extract. Total and specific serum IgE levels were measured. The patients underwent the OSR-bronchial provocation test (OSR-BPT). The day before and 24 h after the OSR-BPT, the methacholine (M)-BPT and induced sputum were performed. Eosinophil percentages and ECP levels were measured in the sputum samples. RESULTS: OSR sensitization (skin tests and specific serum IgE) was detected in all the patients. The OSR-BPT elicited early responses in two subjects. Methacholine sensitivity, sputum eosinophils, and sputum ECP levels increased 24 h after the OSR-BPT in all the patients. CONCLUSIONS: We have demonstrated that inhalation of OSR flour causes bronchoconstriction, induces an eosinophilic inflammatory bronchial response, and increases bronchial hyperresponsiveness in sensitized asthmatics. OSR flour contained in animal fodder should be considered another potential cause of OA among farmers.

Adult↗
PubMed2000

Bias in estimations of DNA content by competitive polymerase chain reaction.

Competitive PCR is a highly sensitive method for specific DNA quantification. Despite the lack of studies related to the accuracy of the method it has been widely used. Here we present a simulation model for competitive PCR, which takes into account the efficiency decay as a linear relationship of the total product yield. The model helped us to study the kind and magnitude of errors that arise from quantitative and semiquantitative competitive PCR protocols and to find ways to minimize them. The simulation data suggest that differences in amplification efficiency between target and standard templates induce stronger biases in quantitative than in semiquantitative competitive PCR. Quantitative competitive PCR can only be used when both efficiencies are equal. In contrast, semiquantitative competitive PCR can be used even when the target is amplified with a higher efficiency than the standard, since under such conditions the method tends to underestimate the differences in initial DNA content. These predictions have been confirmed with experimental data and show that the estimation of the amplification efficiencies is a prerequisite for the use of quantitative and semiquantitative competitive PCR. A simple method for this estimation is also presented.

Animals↗
PubMed2000

Time-dependency of the prognostic effect of carcinoembryonic antigen and p53 protein in colorectal adenocarcinoma.

BACKGROUND: This study examined the prognostic information regarding the risk of postoperative tumor recurrence obtained by simultaneous determination of preoperative serum carcinoembryonic antigen (CEA) and immunohistochemical expression of p53 protein in tumor tissue from patients with colorectal carcinoma. METHODS: A retrospective study of 174 patients (AJCC/UICC Stages I, II and III) was conducted. Serum CEA levels were determined by an enzyme-linked immunoadsorbent assay. Immunohistochemical expression of nuclear p53 protein was assessed in formalin fixed, paraffin embedded archival tumor tissue. The results of both factors were categorized by clinical and histopathologic variables. The relative prognostic significance of all factors with regard to disease free survival was assessed by Cox proportional hazards regression analysis. The stability of the predictive value of both markers was assessed: 1) by splitting the follow-up into three intervals and performing separate analyses for each period and 2) graphically by plotting the corresponding cumulative hazards ratio along the follow-up. RESULTS: Eighty-two (47%) tumors manifested overexpression of p53 protein and 60 tumors (34.4%) exhibited elevated serum CEA levels (cutoff value of 5 ng/mL). p53 positive immunostaining and elevated CEA levels were associated with low cumulative disease free survival at 60 months' of follow-up, and proved to have independent prognostic significance. Analysis performed in different time periods of follow-up showed that the prognostic effect of both markers was not stable over time. The predictive significance of CEA and p53 changed along the study periods. An elevated preoperative CEA level was an indicator of a high risk of recurrence only during the first 2 years after surgery (hazards ratio, 3.26; 95% confidence interval 95% CI, 1.65-6.42). The presence of p53 immunoreactivity in the primary tumor was an indicator of a high risk of recurrence only after the first year of follow-up (hazards ratio, 4.02; 95% CI, 1.68-9.6). CONCLUSIONS: The serum CEA level and expression of p53 protein provide complementary prognostic information. Time-dependency of the prognostic influence of both parameters should be taken into consideration when establishing postoperative predictive estimations.

Adenocarcinoma↗
PubMed2000

Airway inflammation in asthma and perennial allergic rhinitis. Relationship with nonspecific bronchial responsiveness and maximal airway narrowing.

BACKGROUND: Eosinophilic airway inflammation is the hallmark of asthma, but it has also been reported in other conditions such as allergic rhinitis. We have tested whether the analysis of cells and chemicals in sputum can distinguish between patients with mild allergic asthma, those with allergic rhinitis, and healthy controls. The relationship between inflammation markers in sputum and nonspecific bronchial hyperresponsiveness to methacholine (BHR) (PD20 and maximal response plateau [MRP] values) was also evaluated. METHODS: We selected 31 mild asthmatics and 15 rhinitis patients sensitized to house-dust mite. As a control group, we studied 10 healthy subjects. Every subject underwent the methacholine bronchial provocation test (M-BPT) and sputum induction. Blood eosinophils and serum ECP levels were measured. Sputum cell differentials were assessed, and eosinophil cationic protein (ECP), tryptase, albumin, and interleukin (IL)-5 levels were measured in the entire sputum supernatant. RESULTS: Blood eosinophils and serum ECP levels were higher in asthma patients and rhinitis than in healthy controls, but no difference between asthma patients and rhinitis patients was found. Asthmatics had higher eosinophil counts and higher ECP and tryptase levels in sputum than rhinitis patients or control subjects. Sputum albumin levels were higher in asthmatics than in controls. Rhinitis patients exhibited higher sputum eosinophils than healthy controls. An association between sputum eosinophil numbers and MPR values (r= -0.57) was detected, and a trend toward correlation between sputum ECP levels and PD20 values (r= -0.47) was found in the rhinitis group, but not in asthmatics. No correlation between blood eosinophilic inflammation and lung functional indices was found. CONCLUSIONS: Induced sputum is an accurate method to study bronchial inflammation, allowing one to distinguish between rhinitis patients and mildly asthmatic patients. The fact that no relationship was detected between sputum inflammation and BHR suggests that other factors, such as airway remodeling, may be at least partly responsible for BHR in asthma.

Adolescent↗
PubMed2000

Effect of current exposure to Der p 1 on asthma symptoms, airway inflammation, and bronchial hyperresponsiveness in mite-allergic asthmatics.

The existence of a dose-response relationship between indoor allergen exposure and sensitization has been widely described, but the effect of allergen exposure on asthma activity (symptoms, bronchial hyperresponsiveness [BHR], and inflammation) is not clear. Our aim was to determine the existence of an association among current exposure to mite allergens and symptoms, BHR, and airway inflammation assessed in blood and sputum from asthmatic patients sensitized to Dermatophagoides pteronyssinus. We selected 31 mild and recently diagnosed (12-24 months) asthma patients sensitized to D. pteronyssinus. Allergenic exposure (Der p 1, Der 2) was assessed by a commercial assay based on monoclonal antibodies (mAb), carried out on the dust samples collected from patients' beds in a standardized way. Patients completed an asthma symptom questionnaire and underwent skin tests, methacholine bronchial challenge, and sputum induction. Sputum cell profile was analyzed and eosinophil cationic protein (ECP), tryptase, albumin, and interleukin(IL)-5 levels were quantified in sputum supernatant. Total eosinophil numbers and ECP levels were measured in blood samples. Most patients were exposed to Der p 1 levels under 2 microg/g of dust. Der p 1 exposure was higher among the subjects with positive sputum tryptase detection (P = 0.020). Der p 1 levels showed a trend toward correlation with asthma symptoms (P = 0.066, r = 0.36) and correlated with sputum tryptase levels (P = 0.032, r = 0.42). No relationship between BHR, eosinophilic inflammation, and allergenic exposure was found. Our results suggest that asthma symptoms and lung mast-cell activation are at least partially dependent on current allergen exposure. The lack of correlation between mite exposure, eosinophilic inflammation, and BHR supports the role of other factors that enhance the immunologic response initiated by allergen, increasing the activity of asthma.

Allergens↗
PubMed2000

Comparison of allergen-induced changes in bronchial hyperresponsiveness and airway inflammation between mildly allergic asthma patients and allergic rhinitis patients.

Bronchial eosinophilic inflammation and bronchial hyperresponsiveness (BHR) are the main features of allergic asthma (AA), but they have also been demonstrated in allergic rhinitis (AR), suggesting a continuity between both diseases. In spite of not fully reproducing natural allergenic exposure, the allergen bronchial provocation test (A-BPT) has provided important knowledge of the pathophysiology of AA. Our aim was to verify the existence of a behavior of AA and AR airways different from the allergen bronchial challenge-induced airway eosinophilic inflammation and BHR changes. We studied a group of 31 mild and short-evolution AA and 15 AR patients, sensitized to Dermatophagoides pteronyssinus. The A-BPT was performed with a partially biologically standardized D. pteronyssinus extract, and known quantities of Der p 1 were inhaled. Peripheral blood (eosinophils and ECP) and induced sputum (percentage cell counts, ECP, albumin, tryptase, and interleukin [IL]-5) were analyzed, before and 24 h after A-BPT. Methacholine BHR, assessed before and 32 h after the A-BPT, was defined by M-PD20 values and, when possible, by maximal response plateau (MRP). The A-BPT was well tolerated by all the patients. AA presented a lower Der p 1 PD20 and a higher occurrence of late-phase responses (LPR). M-PD20 values decreased in AA, but not in AR, patients. MRP values increased in both groups. Eosinophils numbers and ECP levels increased in blood and sputum from both AA and AR, but only the absolute increment of sputum ECP levels was higher in AA than AR patients (P = 0.025). The A-BPT induced no change in sputum albumin, tryptase, or IL-5 values. We conclude as follows: 1) In spite of presenting a lower degree of bronchial sensitivity to allergen, AR patients responded to allergen inhalation with an eosinophilic inflammation enhancement very similar to that observed among AA. 2) MRP levels increased in both AA and AR patients after allergen challenge; however, M-PD20 values significantly changed only in the AA group, suggesting that the components of the airway response to methacholine were controlled by different mechanisms. 3) It is possible that the differences between AR and AA lie only in the quantitative bronchial response to allergen inhalation.

Adult↗
PubMed2000

Short-term modulation of lipogenesis by macronutrients in rainbow trout (Oncorhynchus mykiss) hepatocytes.

Rainbow trout (Oncorhynchus mykiss) hepatocytes were cultured under simulated conditions of varying nutritional status to explore the short-term modulation by dietary substrates of the main lipogenic enzymes: glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME), ATP-citrate lyase (ACL), acetyl-CoA carboxylase (ACoAC) and fatty acid synthetase (FAS). Primary cultures were individually exposed to varying amounts of glucose, hydrolysed casein and long-chain polyunsaturated fatty acids (PUFA) for 12 h. A second set of experiments was designed to evaluate the effects of mixing different relative amounts of these macronutrients in the culture medium. Glucose concentrations of up to 20-25 mm showed a stimulatory effect on G6PD, ME, ACL and ACoAC activity while an earlier inhibitory effect on FAS was observed at 10-20 mm glucose The use of hydrolysed casein as a nutritional source of amino acids inhibited the activity of FAS and ME and stimulated G6PD, ACoAC and ACL activity Low levels of linolenic acid exerted a stimulatory effect on all the lipogenic enzymes assayed with the exception of FAS, and increased amounts showed some inhibition of lipogenic activities Eicosapentaenoic acid and docosahexaenoic acid showed a similar effect, although the former strongly inhibited FAS activity while the latter showed greater potential to inhibit ACoAC and G6PD. A complete change in the relative levels of glucose, hydrolysed casein and PUFA in turn led to changes in the enzyme activity patterns observed. The present study shows the feasibility of exploring the direct regulation of lipogenesis in isolated fish cells by varying the relative amounts of main macronutrients, mimicking in vivo dietary conditions. It is felt that such an approach may serve to investigate the macronutrient regulation of other metabolic pathways.

Animals↗
PubMed1999

Tobacco allergy: demonstration of cross-reactivity with other members of Solanaceae family and mugwort pollen.

BACKGROUND: Tobacco is a plant belonging to the Solanaceae family. This plant is usually used as a contact insecticide for several infestations in some areas, such as the Canary Islands. Allergy induced by inhalation of this plant is unusual. Identification of the potential allergen in growing areas is essential. OBJECTIVE: We report a patient with occupational sensitivity to an aqueous solution of cut tobacco whose clinical manifestations were rhinoconjunctivitis and urticaria. Past medical history was significant for seasonal allergic rhinoconjunctivitis to mugwort pollen and oral allergy syndrome with avocado. METHODS: Green tobacco and cured tobacco leaf extracts were prepared, skin prick tests were performed with green tobacco, cured tobacco leaf extracts, and certain aeroallergens. Conjunctival challenge test was carried out with green tobacco and cured tobacco leaf extract. Serum-specific IgE against tobacco leaf was performed by commercial CAP. CAP inhibition experiments were carried out with tobacco and Artemisia vulgaris. RESULTS: Skin prick tests and conjunctival challenge tests with green tobacco and cured tobacco leaf extracts were positive, as well as serum-specific IgE by CAP, indicating an IgE-mediated sensitization. CAP inhibition experiments were carried out and it was found that tobacco, mugwort pollen, and tomato extracts inhibited the binding of the patient's serum to solid-phase tobacco leaf. No inhibition was observed when Alternaria, D. pteronyssinus, and potato were used as control inhibitors. Inhibition of immunoCAP to mugwort was obtained with mugwort and tobacco extracts and no cross-reactivity to D. pteronyssinus was shown. CONCLUSION: The results suggest that tobacco can induce IgE-mediated reactions that are mediated by the existence of common antigenic epitopes between tobacco and mugwort pollen. This allergy can be a hazard of employment in the agricultural areas.

Adult↗
PubMed1999

Occupational asthma in a grain worker due to Lepidoglyphus destructor, assessed by bronchial provocation test and induced sputum.

BACKGROUND: Occupational asthma (OA) can be a debilitating disease even when removal from the workplace is achieved. Today, the "gold standard" in the assessment of OA is the bronchial provocation test (BPT). Induced sputum is a non-invasive method of exploring airway inflammation which can provide additional information about such challenges and thus could be applied in OA diagnosis and monitoring. METHODS: We report the study carried out in a grain worker sensitized to Lepidoglyphus destructor (Ld), who suffered from mild asthma at the workplace. Skin prick test and specific serum IgE were measured. Ld-BPT was performed, and the changes in eosinophil rates, and ECP and tryptase levels in induced sputum were studied 30 min and 18 h after Ld-BPT. We also determined the changes in nonspecific bronchial hyperresponsiveness (NSBH), given as PD20 values. To assess the specificity of the changes, we also carried out sputum induction and methacholine challenge after barley-BPT. RESULTS: An isolated immediate response was obtained with Ld-BPT, while barley-BPT was negative. Induced sputum showed higher tryptase levels 30 min after Ld-BPT, and higher eosinophil and epithelial cell percentages and ECP levels 18 h after Ld-BPT. There was also a decrease in methacholine PD20 values after Ld-BPT. Those changes were not observed after barley-BPT. CONCLUSIONS: The study of eosinophilic and mast-cell markers in induced sputum provides additional knowledge about the inflammatory process occurring in the airways, suggesting that the study of induced sputum should be considered in the assessment of OA.

Adult↗
PubMed1999

The partial substitution of digestible protein with gelatinized starch as an energy source reduces susceptibility to lipid oxidation in rainbow trout (Oncorhynchus mykiss) and sea bass (Dicentrarchus labrax) muscle.

We evaluated the influence of dietary gelatinized starch and protein on the fatty acid composition of muscle in rainbow trout and European sea bass and on the susceptibility of flesh to lipid peroxidation. The possibility that flesh peroxidation could be accounted for by lipogenesis and the deposition of fat was also explored. The inclusion of gelatinized starch in the diet of rainbow trout improved growth with respect to that observed in fish fed crude starch (P<.001). This was especially noticeable at the lowest concentration of dietary protein tested (P = .037); suggesting that gelatinized starch may partially replace protein in the production of energy without inducing a negative effect on growth. However, in European sea bass, the gelatinization of starch and dietary protein concentration showed no significant effect on final body weight. The intramuscular neutral lipid concentration of the sea bass was reduced by the gelatinization of dietary starch (P = .034). The highest dietary protein concentration increased the proportion of saturated fatty acids in the neutral (P = .0742) and polar (P = .0033) lipid fractions. The dietary inclusion of high levels of protein in rainbow trout led to a lower concentration of total (n-3) (P = .0457) and (n-6) (P = .0522) fatty acids and a higher concentration of total monounsaturated fatty acids (P = .0006). The inclusion of gelatinized starch led to a lower concentration of (n-3) fatty acids (P = .0034) and a higher concentration of saturated fatty acids (P = .0007). The polar fraction was hardly affected by the same treatment. A significantly lower susceptibility of the dorsal muscle to oxidation was observed in groups of European sea bass fed gelatinized starch (P<.01). A similar trend was observed in rainbow trout, although differences were not significant. The findings suggest that the digestible protein concentration of nutrient-dense diets for rainbow trout and European sea bass can be reduced with a beneficial effect on tissue lipid oxidation and no negative effects on growth and muscle composition.

Animals↗
PubMed1998

Eosinophilic gastroenteritis and Anisakis.

BACKGROUND: The differential diagnosis of eosinophilic gastroenteritis (EG) includes, among other diseases, parasitic infections such as anisakiasis, which has acquired worldwide importance. METHODS: We reviewed all patients referred to our allergy service who had been diagnosed as having primary EG to determine the possible role of Anisakis simplex in the etiopathology of the disease. All patients (n = 10) were studied and diagnosed as having primary EG between 1989 and 1996, inclusive. Two different groups of subjects were used as controls: group A (149 subjects without digestive disorder) and group B (10 subjects with digestive disorder different from EG). Cutaneous prick tests were performed with the main foods, aeroallergens, and commercial extract of A. simplex. Total and specific serum IgE was measured in all patients. Gastric or gut histologic specimens were re-examined in five cases. RESULTS: Peripheral eosinophilia was detected in 40% of the patients with EG, and sensitization to A. simplex was detected in 80% of these. In both control groups, the rate of sensitization to A. simplex was 10%. Sensitization to A. simplex in EG patients with respect to control groups A and B showed odds ratios (OR) of 36 and 40, respectively. In one case, serialization of the histologic section allowed us to observe a whole Anisakis larva. CONCLUSIONS: Immunologic methods to detect specific antibodies against Anisakis should be used routinely before diagnosing EG as primary disorder. Preventive measures are of capital importance.

Animals↗
PubMed1998

Occupational asthma and food allergy due to carmine.

Carmine (E120), a natural red dye extracted from the dried females of the insect Dactylopius coccus var. Costa (cochineal), has been reported to cause hypersensitivity reactions. We report a case of occupational asthma and food allergy due to carmine in a worker not engaged in dye manufacturing. A 35-year-old nonatopic man, who had worked for 4 years in a spice warehouse, reported asthma and rhinoconjunctivitis for 5 months, related to carmine handling in his work. Two weeks before the visit, he reported one similar episode after the ingestion of a red-colored sweet containing carmine. Peak flow showed drops higher than 25% related to carmine exposure. Prick tests with the cochineal insect and carmine were positive, but negative to common aeroallergens, several mites, foods, and spices. The methacholine test was positive. Specific bronchial challenge test with a cochineal extract was positive with a dual pattern (20% and 24% fall in FEV1). Double-blind oral challenge with E120 was positive. The patient's sera contained specific IgE for various high-molecular-weight proteins from the cochineal extract, as shown by immunoblotting. Carmine proteins can induce IgE-mediated food allergy and occupational asthma in workers using products where its presence could be easily overlooked, as well as in dye manufacture workers.

Adult↗
PubMed1998

Dietary fish oil and digestible protein modify susceptibility to lipid peroxidation in the muscle of rainbow trout (Oncorhynchus mykiss) and sea bass (Dicentrarchus labrax).

The effects of dietary fish oil and digestible protein (DP) levels on muscle fatty acid composition and susceptibility to lipid peroxidation were studied in two representative fish species for human nutrition, from fresh and seawater, rainbow trout (Oncorhynchus mykiss) and European sea bass (Dicentrarchus labrax). In rainbow trout, higher concentrations of dietary fat and DP led to higher weight gain (g/d) (P = 0.001 and P = 0.043 respectively). Additionally, an interaction effect was observed in this species, since the effect of DP was only evident when the dietary fat concentration was low (P = 0.043). A similar tendency was also observed in European sea bass, although with less marked differences among nutritional treatments. Trout fed on diets with a higher concentration of dietary fat had higher concentrations of intramuscular total and neutral lipids in the dorsal muscle (P = 0.005). Increased levels of dietary DP led to significantly lower concentrations of polar lipids in the dorsal muscle of both rainbow trout (P = 0.005) and European sea bass (P = 0.006). In the neutral fraction of intramuscular lipids of dorsal muscle the concentration of n-3 fatty acids was positively affected by the dietary fat concentration in both rainbow trout (P = 0.04) and sea bass (P = 0.001). Muscle homogenates from trout and sea bass fed on diets rich in fish oil showed a significantly higher susceptibility to oxidation than muscle homogenates from fish fed on low-fat diets (P = 0.001). The higher DP concentration also increased susceptibility to oxidation. Moreover, in rainbow trout an interaction effect was observed where the pro-oxidant effect was of higher magnitude when the dietary concentration of both nutrients, fat and protein, was high (P = 0.004).

Animal Nutritional Physiological Phenomena↗
PubMed1997

[Andermann syndrome: presentation of a case].

INTRODUCTION: Peripheral neuropathy with agenesis of the corpus callosum (or Andermann's syndrome) is a hereditary autosomal recessive disorder rarely found outside certain regions of Quebec Province (Canada). It is associated with mental retardation and various dysmorphic changes. Deterioration is usually progressive with loss of motor skills, development of scoliosis during adolescence, tendency to behaviour disorders and death during the third decade (approximately). CLINICAL CASE: We present a 13 year old girl diagnosed as having the spastic tetraparesic type of PCI, who was sent to us so that we could reconsider the diagnosis in view of the atypical course of the illness. The patient had an unusual phenotype with dysmorphic changes (mainly facial), axial hypotonia with flexion-retraction of the hands, generalized arreflexia, neurogenic bladder, skin changes with ulcers on the legs and mental retardation. Neurophysiological studies showed a predominantly motor polyneuropathy. There were signs of axonal neuropathy on both sural nerve and skeletal muscle biopsies. The clinical features, phenotype, microcephaly with agenesis of the corpus callosum and a posterior fossa cyst, associated with spinal atrophy indicated the diagnosis of Andermann's syndrome. CONCLUSIONS: This case is of interest in view of the exceptional rarity of Andermann's syndrome in our population.

Adolescent↗