Search PubMed⌕ Search

Biomedical subjects

M J Alvarez

Publications and source records attributed to M J Alvarez.

At least 19 recordsLinked to original sources
PubMed2005

Dietary protein source affects lipid metabolism in the European seabass (Dicentrarchus labrax).

The study was undertaken to evaluate the effects of dietary protein sources on lipogenesis and fat deposition in a marine teleost, the European seabass (Dicentrarchus labrax). Four isonitrogenous (crude protein (CP, Nx6.25), 44% DM) and isoenergetic (22-23 kJ/g DM) diets were formulated to contain one of the following as the major protein source: fish meal (FM), one of two soy protein concentrates (SPC) and corn gluten meal (CGM). Apparent digestibility coefficients of the diets and raw ingredients, as well as soluble nitrogen (ammonia and urea) and phosphorus excretion were measured. Growth rates of seabass fed plant protein-based diets were significantly lower than those fed fish meal based diet. The protein utilisation was strongly correlated to the dietary essential amino acids index. Measurements of N excretion (ammonia and urea nitrogen) confirmed these data. Daily fat gain at the whole body level ranged between 1.1 to 1.7 g/kg BW, with the highest values being recorded in fish fed the fish meal based diet. Levels of plasma triglycerides and cholesterol were lower in fish fed soy protein diets than in those fed the diet solely based on fish meal. Soy protein rich diets decreased the activities of selected hepatic lipogenic enzymes (glucose 6-phosphate dehydrogenase, malic enzyme, ATP-citrate lysase, acetylcoenzyme A carboxylase and fatty acid synthetase). Highest lipogenic enzyme activities where found in fish fed the fish meal diet, except for fatty acid synthetase which was increased in seabass fed the corn-gluten meal based diets. Overall data suggest that dietary protein sources affects fat deposition and the lipogenic potential in European seabass.

Animals↗
PubMed2003

[Allergy to asparagus].

Asparagus (Asparagus officinalis) is a widely grown vegetable; together with garlic, the onion and the leek, it belongs to the Liliaceae family. Both delayed cell-mediated reactions and IgE-mediated reactions secondary to asparagus have been described. While the former (allergic contact dermatitis) are a fairly common cause of occupational disease, only a few case-reports of IgE-mediated reactions have been published. IgE-mediated reactions can be further grouped into food allergy and reactions due to cutaneous or respiratory exposure, which is often occupational. Anaphylaxis is the most common clinical picture of food allergy, while contact urticaria, rhinitis and asthma, appearing either isolated or associated, are clinical pictures of the latter. Sensitization to different allergens is the likely cause of the different clinical pictures due to asparagus. Their detection and early diagnosis is of prime importance due to the different prognosis and treatment. In the present article we resume our experience over the last 5 years.

Allergens↗
PubMed2003

[From rhinitis to asthma, one or two diseases?].

Rhinitis and asthma commonly coexist in allergic patients. This observation might be attributable to their coexistence in time, but it is also possible that both diseases are the opposite poles of a single disease affecting the respiratory system, or even an anomalous systemic immune response to the allergen. Nose-lung interactions have been widely studied from epidemiological, physiopathological, aetiological and pharmacological aspects. In the present article we review this topic and its main clinical implications.

Asthma↗
PubMed2003

[New techniques in the study of asthma].

Asthma is a chronic inflammatory disease of the airways that is functionally characterized by variability of lung function and bronchial hyper-responsiveness. Its diagnosis and management is commonly hampered by the lack of objective parameters. This article reviews additional techniques for evaluating both, lung function (bronchial challenge with adenosin-monophosphate, lung resistance measurement by either the impulse oscillometry system or whole body pletismography) and bronchial immuno-inflammatory response (induced sputum, condensates of exhaled air, monitoring of nitric oxide in exhaled air), as well as our experience with them.

Airway Resistance↗
PubMed2003

[Latex. An important aeroallergen involved in occupational asthma].

Latex has become one of the most frequent aetiological agents of occupational asthma in the last decade, especially amongst health personnel. The prevalence of occupational asthma due to latex in the different affected occupations varies between 2.5 and 10%, figures that give an idea of the magnitude of the problem. Latex proteins, absorbed in the dust of cornstarch, used as a lubricant, are responsible for asthma due to latex gloves. This cornstarch dust that covers the inside of the gloves acts as a vehicle for dispersing allergenic proteins. Latex aeroallergens are found in particles of different dimensions. The levels of latex aeroallergens in the environment capable of causing sensitization and of unleashing symptoms are not well defined. The determination of these levels of exposure to latex is complicated, since with latex one is dealing with a complex mixture of allergens with differing stability and bio-availability. The bioaerosol of latex is mainly produced by the active use of powdered gloves, but rugs or carpets and coverings act as important reservoirs of the allergen. Besides, the movement of people from areas with a high environmental concentration of latex constitutes an important means of dispersing the allergen, and probably ventilation systems as well. As in other cases of occupational asthma, diagnosis in many cases requires that a bronchial challenge be realized. The specific challenge tests through inhalation with latex have been carried out by different methods, which can be grouped by those that use an aqueous extract of latex and those that consist in handling or shaking gloves, which thus generate a dust aerosol. Each method has its advantages and drawbacks as described. Once the sensitized patient begins manifestations of the disease, his prognosis is poor if measures aimed at a maximum reduction of exposure to latex are not applied.

Allergens↗
PubMed2003

Occupational asthma from natural rubber latex. Specific inhalation challenge test and evolution.

BACKGROUND: Natural rubber latex (NRL) is the most frequent cause of occupational respiratory problems in hospital workers. OBJECTIVE: To describe the diagnostic methodology, including the specific inhalation challenge (SIC), used on patients diagnosed as having occupational asthma due to NRL in our Allergy Department during a 6-year period from 1989 to 1995. METHODS: In 19 patients diagnosed as having occupational asthma due to NRL, clinical severity was assessed with a combined score for symptoms and medication use. Skin prick tests with aeroallergens, latex, papain, kiwi and chestnut, total IgE, serum-specific latex IgE, respiratory function study, methacholine test, specific conjunctival test, and SIC test with latex were done. RESULTS: All but three patients worked in hospitals. All presented urticaria and rhinoconjunctivitis, and six also suffered anaphylaxis, usually preceded by asthma. Clinical fruit allergy was present in eight patients. The latency period was variable (0.25-27 years). The intensity of symptoms was low to moderate. Specific IgE, skin prick, and conjunctival tests to latex were positive in all cases. SICs were done in 12 patients. All of them presented isolated immediate reactions. No adverse reactions were observed. Duration of follow-up ranged from 1 to 7 years. Twenty-six percent of the patients kept their job, 26% changed jobs but remained in health care, and 48% switched to jobs unrelated to health care. Only 16% were free of symptoms without treatment, while 32% needed bronchodilators and 52% needed inhaled steroids. The specific bronchial challenge test was safe, but it did not predict the course of the illness. Duration of exposure and intensity of symptoms did correlate with prognosis, however. CONCLUSIONS: NRL acts as a common aerollergen. Minor symptoms often precede occupational asthma. The SIC test was safe in the hands of trained technicians. Occupational asthma due to NRL seems to have a poor prognosis.

Adult↗
PubMed2002

Liposome-entrapped D. pteronyssinus vaccination in mild asthma patients: effect of 1-year double-blind, placebo-controlled trial on inflammation, bronchial hyperresponsiveness and immediate and late bronchial responses to the allergen.

BACKGROUND: Allergen vaccination is effective in mite-allergic asthma. Liposomes are immunological adjuvants that can act as allergen carriers. OBJECTIVE: To evaluate the immunological and functional effects of a liposome-entrapped D. pteronyssinus vaccine on mite monosensitive, mild asthma patients. METHODS: A double-blind, placebo-controlled trial was conducted on 26 asthma patients who randomly received vaccination or placebo for 1 year. The levels of exposure to Der p 1 allergen were constant during the study. Allergen bronchial challenge was made at the beginning (T0) and after 1 year of treatment (T12). The day before and 24 h after the allergen provocation, patients were challenged with methacholine (Mth) (until FEV1 fell by 40%) and blood and sputum samples were obtained. Dose-response curves to Mth were evaluated in terms of Mth-PD20 (dose of Mth that induced 20% drop in FEV1), slope (Mth-DRS) and level of plateau. Blood and sputum eosinophils and serum levels of eosinophil cationic protein (ECP) and intercellular adhesion molecule-1 (ICAM-1) were measured. RESULTS: Groups were comparable at the start of the trial. At TI2, previous to the allergen challenge, the active group showed higher values of both FEV1 and Mth-PD20 and lower values of Mth-DRS. The number of patients presenting a level of plateau increased in the active group (from two to four) and decreased in the placebo group (from two to one). At T12, before the allergen challenge, serum ECP levels increased in the placebo group and blood eosinophils showed a trend towards lower numbers in the active one. The immediate response and the changes in Mth-DRS values, sputum eosinophils and serum ECP levels following the allergen challenge were attenuated in the active group. CONCLUSION: Liposome-entrapped D. Pteronyssinus vaccination: (i) protects mild asthma patients from the worsening of asthma due to sustained mite exposure; and (ii) reduces the functional and inflammatory changes induced by allergen bronchial provocation.

Adult↗
PubMed2002

[The child with attention deficit hyperactivity disorder (ADHD). Hyperkinetic multi-disciplinary therapeutic approach].

Attention deficit disorder has a high prevalence in the infant population: from 3 to 5% of children of school age and, it could be as high as 8.1 + 2.7% of children at ten years of age, according to a study in the autonomous community of Valencia. It is a persistent problem whose manifestations can change in the course of its development, from pre-school age to adult life. In this paper we review the disorder in its epidemiological and etiological aspects, its natural history and its prognosis, as well as its diagnosis and treatment. We set out our experience with children and their families in two primary care paediatric units of the Navarra health service in two different settings - rural and urban. Finally, we draw attention to some of the difficulties faced in dealing with this disorder in a reasonable way.

English Abstract↗
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↗