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Biomedical subjects

M C Santos

Publications and source records attributed to M C Santos.

At least 55 records · Page 3Linked to original sources
PubMed1991

Platelet aggregation in allergic reactions.

The platelet aggregation in the presence of 4 aggregation inducers was studied in 63 allergic patients, consisting of atopic and non-atopic asthmatics and aspirin-sensitive subjects, before and after inhalation tests or in vitro incubation with allergen. Basal platelet aggregation was decreased in 43% of the atopic patients for adrenaline and also in a smaller percentage for other agonists. A decreased aggregation was also observed in 3 out of 6 nonatopic patients and in aspirin-sensitive patients. In vivo or in vitro provocation tests decreased aggregation in some additional patients. These results point out to a compromise of platelets in allergic mechanisms.

Humans↗
PubMed1991

Cellular interactions in asthma.

Immediate phase of asthma is induced by mast cells. Late phase asthmatic response is related to other cells such as, macrophages, lymphocytes, eosinophils, and could pass to chronicity and is usually associated with bronchial hyperreactivity. Pathological or functional studies of the different cells involved, could be done in peripheral blood, broncho-alveolar lavage, bronchial biopsies or nasal lavages.

Asthma↗
PubMed1991

T cells, macrophages and platelets in asthma.

The role of T cells, macrophages and platelets in asthma is discussed. Peripheric T cell populations are normal as well in atopic as in non atopic. Macrophages can release histamine releasing factors and PAF in presence of allergens. Platelets stimulated by contact with allergens or PAF decreased the aggregation pattern induced by common inducers. These data show that different cells can play a role in the inflammatory process in asthma.

Asthma↗
PubMed1989

[Platelet aggregation in asthma].

Platelet activation is one of the aspects of cellular interaction causing inflammation in asthma. Platelet aggregation has been studied in asthmatic patients in presence of different aggregation inducers (epinephrine, ADP, arachidonic acid). In 20 to 40% of the atopic asthmatic patients depending on the inducer and in some patients with non atopic asthma or aspirin sensitivity and asthma platelet aggregation is decreased. Bronchial provocation tests have not decreased platelet aggregation except in few cases. In vitro incubation of platelets with allergen extract has provoked an hypoaggregation mainly when incubation time or allergen concentration were increased. Platelets seem to play an important role in the inflammatory component of bronchial asthma.

Adenosine Diphosphate↗
PubMed1986

Cation composition and osmolality of the hemolymph of the terrestrial crab Gecarcinus lagostoma.

Hemolymph cation concentration and osmolality are reported for male and female specimens of the terrestrial crab Gecarcinus lagostoma collected on Trindade Island, Brazil (20 degrees 36'36" S and 29 degrees 19'26" W). Data for 9 female crabs weighing 133.7 +/- 25.4 g (mean +/- SD) were: osmolality, 816 +/- 85 mOsm/kg H2O; Na+, 357 +/- 55; K+, 7.9 +/- 0.8; Ca2+, 33.5 +/- 2.8 and Mg2+, 15.6 +/- 2.5 mEq/l. There were no significant differences between the female (N = 9) and male (N = 9) hemolymph parameters. The hemolymph Na+, K+, Ca2+ and Mg2+ concentrations and osmolality of G. lagostoma were higher (P less than 0.01) than those of U. cordatus, a previously studied Brazilian gecarcinid crab. These differences are probably due to the higher degree of terrestriality of G. lagostoma compared to U. cordatus.

Animals↗
PubMed1982

Effect of Eu3+ on the lipid biosynthesis in rat liver.

The influence of Eu3+ on lipid biosynthesis of female rat liver was studied. 24 hours after the intramuscular injection of europium chloride an infiltration of triacylglycerols on the liver was observed but cholesterol content was unaffected. These results demonstrate that europium produces the same effect as other lanthanides with a lower atomic number ; those lanthanides with a higher atomic number have no effect [1]. The specific radioactivity of triacylglycerols obtained from [1-14C] acetate by liver slices of rats injected with this ion 18-24 hours before decreases but there is an increase of the incorporation of the same precursor into cholesterol 12-24 hours after the administration of the lanthanide ion.

Animals↗
PubMed1982

Joint mobility in children: a population study.

The mobility of five joint pairs ( metacarpophalangeal, wrist, elbow, knee and ankle) was investigated in 3,000 mixed school children of Bahia, Brazil. A sampling method was designed to assure an equal number of fifty children in the smallest classes, when age, race and sex were held constant. Race was classified in five subgroups to assess the proportion of Black admixture. Multiple regression was carried out to analyze the data. The results showed a consistent effect of age on decreasing joint mobility, The effect of race was also on decreasing mobility of wrist, elbow and ankle; the darker the child, the less the joint mobility. However, the effect of sex showed no general consistency; for wrist, elbow and knee the girls had more mobility than the boys; for the ankle the boys had more mobility than the girls; and the metacarpophalangeal joint there was no sex difference. The complexity of multicausal effects on joint mobility are discussed considering the simultaneous interplay of biological and environmental actions.

Adolescent↗
PubMed1981

Generalized joint hypermobility and black admixture in school children of Bahia, Brazil.

Joint hypermobility was investigated in a sample of 3,000 school children, ages 6--7 years, in Bahia, Brazil. A sampling method was designed to assure an equal number of 50 children in the smallest size classes, when age, race, and sex were held constant. Race was classified in five subgroups to assess the proportion of black admixture. The overall frequency of generalized joint hypermobility was 2.3%. The darker the children the lower the frequency of affected children. However, this racial effect was also associated with age: The highest frequency of generalized joint hypermobility was among the youngest and less black mixed children, whereas among the oldest and darker children there was no case of joint hypermobility.

Adolescent↗
PubMedDate not supplied

The effect of age and selenium on some biochemical parameters in rat liver.

Two age groups, 3 and 15 mo, were used to investigate whether age-associated changes in some parameters related to lipid peroxidation occur in the liver of male Wistar rats and to observe possible effects of dietary selenium supplementation (0.25 and 0.50 ppm) for 12 mo on the same parameters. At these experimental conditions, the most important observation was that peroxidation did not change by aging, at least until 15 mo of age. In addition, the activity of Se-dependent glutathione peroxidase (GSH-Px, EC 1.11.1.9) was higher in the liver of the older animals. It is suggested that the enzyme could have a role in the unchanged hepatic peroxidation observed in aged male rats. On the other hand, an effect of dietary selenium supplementation on those parameters was not observed, probably because the selenium levels were still at an adequate plateau.

Aging↗
PubMedDate not supplied

Effect of selenium supplementation on some blood biochemical parameters in male rats.

The long-term effect of selenium supplementation on blood glutathione peroxidase (GSH-Px) activity and plasma TBARS' production (as an index of peroxidation) was evaluated in 15-mo-old male rats fed a diet supplemented with 0.25 or 0.50 ppm selenium, for 12 mo. A group of nonsupplemented age-matched rats was the control. In addition, triglycerides, phospholipids, total and free cholesterol, HDL-cholesterol, and HDL-phospholipids levels were measured in plasma. Plasma testosterone levels were also determined in order to control the aging process in these animals. The GSH-Px activity and the peroxidation level were unchanged in all the groups. However, concerning the lipid parameters, a decrease in triglycerides concentration was observed in both treated groups (p < 0.05). Therefore, in these experimental conditions, despite no observed changes in parameters related to lipid peroxidation, selenium seems to be involved with triglycerides metabolism, eventually improving the triglycerides status of aged animals.

Animals↗
PubMedDate not supplied

Systemic markers of the redox balance in chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is highly prevalent and its pathogenesis is still not completely clarified. Clinically stable patients (n=21) and healthy subjects (n=24) were studied for blood markers of oxidative injury and antioxidant status. The plasma concentration of protein carbonyls was significantly increased in COPD patients, both ex-smokers (0.76 +/- 0.28 nmol mg(-1)) and smokers (0.99 +/- 020 nmol mg(-1)) versus controls (0.49 +/- 0.14 nmol mg(-1)) . The concentration of total thiols was slightly enhanced in plasma of the COPD patients (ex-smokers 492 +/- 23 micromol 1(-1) and smokers 505 +/- 36 micromol 1(-1) versus controls 450 +/- 67 micromol 1(-1); p < 0.05). The activity of the antioxidant enzyme superoxide dismutase was increased in erythrocytes (activity in U g(-1) haemoglobin; ex-smokers 4460 +/- 763 and smokers 4114+/- 1060 versus 3015 +/- 851 in controls; p > 0.01), while glutathione peroxidase activity was decreased in total blood (activity in U g(-1) haemoglobin: ex-smokers 27 +/- 9 and smokers 23 +/- 9 versus 47 +/- 25; p < 0.01). Lower levels of selenium in plasma were also found for COPD patients (concentration in mg 1(-1): ex-smokers 0.030 +/- 0.019 and smokers 0.032 +/- 0.024 versus 0.058 +/- 0.023 in controls; p < 0.01), being more evident in those with very low levels of arterial oxygen pressure. In addition, the levels of potassium and rubidium were increased in blood cells of the patient group. All these changes might reflect oxidant damage and an altered electrolytic homeostasis, and can be interpreted as markers of COPD rather than as indicators of smoking habits.

Aged↗
PubMedDate not supplied

Whole blood glutathione peroxidase and erythrocyte superoxide dismutase activities, serum trace elements (Se, Cu, Zn) and cardiovascular risk factors in subjects from the city of Ponta Delgada, Island of San Miguel, The Azores Archipelago, Portugal.

Activities of whole blood glutathione peroxidase (GSH-Px) and erythrocyte superoxide dismutase (SOD) and serum levels of selenium (Se), copper (Cu) and zinc (Zn) were measured in 118 apparently healthy subjects aged 20-60 years from the city of Ponta Delgada, Island of San Miguel, The Azores Archipelago, Portugal. Data were analysed by age/gender, lipid profile and blood pressure as cardiovascular risk factors searching for their relevance when assessing reference values for antioxidant biomarkers. GSH-Px was in the same range, but SOD was significantly lower than in other Portuguese populations. Neither activity differed with gender. GSH-Px activity increased with age, namely in normolipidemic men versus the hyperlipidemic group in which a decrease was observed. This suggests a progressive impairment of GSH-Px with age caused by an enhanced production of oxidant species in hyperlipidemia. GSH-Px was 30% lower in male hypertensives versus normotensives. SOD activity did not relate to age or blood pressure but was 17% higher in the hyperlipidemic men versus the normolipidemic group, suggesting a better antioxidant protection by SOD than by GSH-Px in hyperlipidemia and hypertension. Se was higher in men versus women, particularly in the older subjects, and partly related to hyperlipidemia. Zn levels showed a similar dependency on gender, not related to age or lipid profile. Cu levels were much higher in women than in men in all age or lipid profile classes and decreased in hyperlipidemia. They were lowered with age in both genders, particularly in normolipidemic women. The present research therefore suggests that hyperlipidemia and hypertension do affect antioxidant status and should be considered when assessing antioxidant biomarkers in blood.

Adult↗
PubMedDate not supplied

[Epidemiologic survey with histoplasmin and paracoccidioidine in Arapiraca-Alagoas].

Paracoccidioidin and histoplasmin intradermic tests were performed in 107 inhabitants in Arapiraca, Alagoas. The epidemiological survey was performed in both sexes and the ages varied from 2 to 71 years. Positive results with paracoccidioidin test were recorded in 11% and the histoplasmin test was positive in 14%. With the positivity of paracoccidioidin in the histoplasmin positive population the result shows a percentage of 33.33%, while with the positivity of histoplasmin in the paracoccidioidin positive population was 41%.

Adolescent↗
PubMedDate not supplied

[Ocular manifestations in HIV infected patients attending the department of ophthalmology of Universidade Federal de São Paulo].

PURPOSE: To evaluate ocular manifestations of HIV-infected patients. MATERIAL AND METHODS: A retrospective study of 1,100 HIV positive out patients in 3 years with a standard complete ophthalmological exam. RESULTS: Eight hundred and sixty nine (79%) of the 1,100 patients studied were male and 231 (21%) female. The most important risk factors were: male homosexuality in 303 cases (27.55%), heterosexuality in 272 (24.73%), endovenous drugs use in 168 (15.27%), and unknown cause in 246 (26.36%). Related to ocular complains, we found 432 (39.27%) patients with decreased visual acuity, 138 (12.55%) with visual hazy, 64 (5.82%) with ocular pain, 186 (16.9%) with inspecific complaints, and 235 (21.36%) with no complains. The most frequent ocular manifestations were: CMV retinitis in 246 (22.36%), cotton wool spots in 110 (10%), blepharitis in 51 (4.64%), and toxoplasmosis in 48 (4.36%). CONCLUSION: The increase of disease ratio was observed among heterosexual and females in this specific population. Patients with ocular complains were 79.42%. The most frequent ocular manifestations was CMV retinitis, in 246 (22.36%). We found also 10% of cotton wool spots.

Brazil↗
PubMedDate not supplied

Soil chemical changes under irrigated mango production in the Central São Francisco River Valley, Brazil.

Irrigated areas in Brazil's Central São Francisco River Valley have experienced declines in productivity, which may be a reflection of changes in soil chemical properties due to management. This study was conducted to compare the chemical composition of soil solutions and cation exchange complexes in a five-year-old grove of irrigated mango (Mangifera indica L. cv. Tommy Atkins) with that of an adjacent clearing in the native caatinga vegetation. A detailed physiographic characterization of the area revealed a subsurface rock layer, which was more undulating than the current land surface, and identified the presence of a very saline and sodic (1045 microS cm(-1), sodium adsorption ratio [SAR] = 5.19) ground water table. While changes in concentrations of Ca, Mg, and K could be attributed to direct management inputs (fertilization and liming with dolomite), increases in Na suggested average annual capillary rise from the ground water table of 28 L m(-2). Accordingly, soil salinity levels appeared to be more dependent on surface elevation than the elevation of the rock layer or sediment thickness. The apparent influence of land surface curvature on water redistribution and the solution chemistry was more pronounced under irrigated mango production. In general, salinity levels had doubled in the mango grove and nearly tripled under the canopies, after only five years of irrigation. Though critical saline or sodic conditions were not encountered, the changes observed indicate a need for more adequate monitoring and management of water and salt inputs despite the excellent water quality of the São Francisco River.

Agriculture↗
PubMedDate not supplied

Nasal provocation and immunotherapy.

Nasal mucosa is heavily exposed to inflammatory and allergic stimuli, rhinitis being the most common form of allergic respiratory disease. The nose is an easily accessible organ and a good model for the study of allergies as it makes it possible to monitor the effects of specific challenges as well as therapeutic interventions, namely specific immunotherapy (SIT). Injectable, nasal or sublingual SIT are useful therapeutic strategies in the management of allergic rhinitis patients. Monitoring the evolution of parameters such as clinical scores, nasal peak flow variation or drug requirements during SIT provides important information on its clinical efficacy. Laboratory measurement of tryptase and eosinophil cationic protein in the target organ after specific nasal provocation makes it possible to record changes in the release of mast cell and eosinophil mediators, thus providing objective evidence of the immunological efficacy of this therapy on these cell populations and providing data which eventually will contribute to a better understanding of the multiple mechanisms of action of allergen desensitization therapy.

Asthma↗