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C Silva

Publications and source records attributed to C Silva.

126 records · Page 7Linked to original sources
PubMedDate not supplied

Air pollution impact on phagocytic capacity of peripheral blood macrophages and antioxidant activity of plasma among school children.

Peripheral blood macrophages of school children from downtown Santiago, Chile--a highly polluted city--exhibited a lower phagocytic index with higher percentage of killing than those of the rural village of María Pinto. These findings were observed concomitantly with a lower antioxidant activity of plasma in Santiago students. No differences were observed in serum immunoglobulins (IgA, IgG, and IgM), secretory IgA in saliva, and complement component C3. White blood cell count was higher in María Pinto residents than in Santiago students, including those cells with phagocytic capacity. It is suggested that particulate air pollution may enhance macrophage activity with impairment of the antioxidant capacity of plasma.

Adolescent↗
PubMedDate not supplied

Skeletal maturity and socio-economic status in Portuguese children and youths: the Madeira growth study.

BACKGROUND: Skeletal maturity is used to evaluate biological maturity status. Information about the association between socio-economic status (SES) and skeletal maturity is limited in Portugal. AIMS: The aim of this study is to document the skeletal maturity of youths in Madeira and to evaluate variation in maturity associated with SES. SUBJECTS AND METHODS: The study involved 507 subjects (256 boys and 251 girls) from the Madeira Growth Study, a mixed-longitudinal study of five cohorts (8, 10, 12, 14 and 16 years of age) followed at yearly intervals over 3 years (1996-1998). A total of 1493 observations were made. Skeletal age was estimated from radiographs of the hand and wrist using the Tanner-Whitehouse 2 method (TW2). Social class rankings were based on method. Five social rankings were subsequently grouped into three SES categories: high, average and low. RESULTS: Median for the radius, ulna and short finger bones (RUS scores) in the total sample of boys and girls increased curvilinearly across age whereas median for the 7 (without pisiform) carpal bones (Carpal scores) increased almost linearly. The 20-bone maturity scores demonstrated distinctive trends by gender: the medians for boys increased almost linearly while the medians for girls increased curvilinearly. SES differences were minimal. Only among children aged 10-11 years were high SES boys and girls advanced in skeletal maturity. Madeira adolescents were advanced in skeletal maturity compared with Belgian reference values. CONCLUSION: The data suggests population variation in TW2 estimates of skeletal maturation. Skeletal maturity was not related to SES in youths from Madeira.

Adolescent↗
PubMedDate not supplied

Gradients of HLA diversity in South American Indians.

Information concerning the HLA-A and -B loci was considered in relation to 3796 Amerindians living in 39 places in South America, data related to HLA-C being based on a smaller subset of 2989 persons distributed among 33 localities. Synthetic gene frequency maps were then constructed using principal-components analysis. Clearly significant longitudinal (principal component 1) and latitudinal (principal components 1, 2, and 3) clines were observed, most probably indicating ancient migration routes.

Alleles↗
PubMedDate not supplied

Safety behaviors of abused women after an intervention during pregnancy.

OBJECTIVE: To evaluate an intervention protocol, administered during pregnancy, for increasing safety-seeking behaviors of abused women. DESIGN: Prospective, ethnically stratified cohort analysis. SETTING: Public prenatal clinics. PARTICIPANTS: Pregnant women reporting physical or sexual abuse in the year before or during the present pregnancy. One hundred thirty-two women met study criteria, received the intervention, and were followed for 1 year after the completion of the pregnancy. INTERVENTION: Three education, advocacy, and community referral sessions that included information on safety behaviors. MAIN OUTCOME MEASURE: Adoption of safety behaviors by abused women. Safety behaviors were measured before the intervention, twice during pregnancy, and at 2, 6, and 12 months after completion of the pregnancy. RESULTS: Repeated measures analysis of variance showed a significant increase in adoption of each safety behavior (p < .0001), with most behaviors showing a significant increase after the first intervention session. CONCLUSIONS: Pregnant women who were abused and were offered an intervention protocol report a significant increase in safety behavior adoption during and after pregnancy. Abuse during pregnancy is common. Identification of abuse and immediate clinical intervention that includes information about safety behaviors can result in safety behavior adoption that may prevent future abuse and increase the safety and well-being of women and infants.

Adolescent↗
PubMedDate not supplied

[Aids neurologic manifestations in childhood].

INTRODUCTION: Children with AIDS get infected mainly by vertical transmission. DEVELOPMENT: That was what happened in 90% of the cases in a series of 340 HIV+ children followed at Hospital de Clínicas de Porto Alegre, Brazil. Currently, after the use of prophylactic treatment during pregnancy and the six first weeks of life, our transmission rate is 3% to 4%. The incidence of neurologic complications in the vertical transmission group was 49% in our prospective series, and due either to immunosuppression or primary neurological disease. Neurologic changes secondary to HIV constitute a complex syndrome, manifested by various degrees of cognitive, motor and behavioral delay. Encephalopathy can be either progressive or static. In our series, encephalopathy occurred in 32.5% of cases, developmental delay in 42.5%, seizures in 6%, speech delay in 5%, headaches in 2.5% and behavioral disorders in 2%. Central nervous system infections happened in 33.8% of our cases: acute bacterial infections in 11%, cytomegalovirus in 6.8%, toxoplasmosis in 5.9%, cryptococcal in 5%, tuberculous in 3.8% and syphilis in 1.3%. Hemorrhagic cerebrovascular accidents were seen in 2.5% of our cases, and peripheral neuropathy in 5%. Seventy percent of our cases had abnormalities in the CSF, 75% in brain CT scans and 45% in EEGs. CONCLUSIONS: Treatment of children with AIDS and neurologic manifestations was based on specific drugs aimed at controlling viral replication. Best response was obtained with combined use of AZT and other anti-retroviral neuro-protective.

AIDS Dementia Complex↗
PubMedDate not supplied

HPLC detection of thioperamide from biological samples and its determination in rat blood and brain after systemic administration.

Thioperamide is a potent and selective antagonist on histamine H3 receptors. A method for its isolation and quantitation by HPLC from rat plasma and brain samples has been developed. Using this technique, thioperamide concentrations in rat plasma and brain were measured after systemic administration, in order to evaluate its persistence in blood and its ability to cross the blood-brain barrier. We observed that, at a dose of 60 mg/Kg, thioperamide undergoes a slow elimination from plasma, with a half-life of 10 hours, and can readily cross the blood-brain barrier.

Animals↗
PubMedDate not supplied

[The obstructive sleep apnoea syndrome in obesity: a conspirator in the shadow].

The obstructive sleep apnoea syndrome (OSAS) is caused by upper airway collapse during sleep. These episodes are associated with recurrent oxyhaemoglobin desaturations and arousals which lead to disruption of the sleep pattern and cognitive deterioration. Factors such as age, male sex, menopause, tobacco and alcohol consumption and anatomic abnormalities are demonstrated risk factors for OSAS development. Obesity, specially of abdominal type, is also a very strong predictor of OSAS, increasing the risk of apnoea by ten times. OSAS prevalence may reach 80% and 50% en males and females with morbid obesity respectively. OSAS induces sympathoexcitation, insulin resistance, renin-angiotensin system activation, oxidative stress, endothelial dysfunction, hypercoagulability and reduction of fibrinolysis leading to hypertension and increased cardiovascular risk. The best diagnostic procedure is polysomnography. Obesity treatment is followed by a dramatic improvement in OSAS. Weight loss of 10% results in reductions of apnoea index by 26%. Application of a positive pressure system is a very effective treatment for OSAS which reduces the apnoea index and improves cardiovascular risk and cognitive impairment.

Cardiovascular Diseases↗
PubMedDate not supplied

[Importance and characteristics of burns in a pediatric emergency service].

The purpose of this study was to describe the magnitude and some relevant aspects of children with burn injuries as seen at the emergency room of a metropolitan hospital at Santiago, Chile, from a random sample of 22,430 consultations from a total of 137,220. Two hundred and thirty seven burn injuries were detected corresponding to 5.2% of all surgical consultations and 1.1% from the whole sample, 56.5% occurring in males, 73.4% of the affected patients were under 5 years of age, 72% of lesions were caused by hot liquids, 51.6% affected the upper limbs and 4.5% were considered to require admission to hospital wards. Consultations most frequent in july (winter) the lesser incidence occurring in february (summer). Preventive programs addressed to burn injuries should cover children under 5 years of age and should be specially focussed on winter and safe handling of hot liquids.

Adolescent↗
PubMedDate not supplied

[Specificity of the resistance exhibited by peritoneal macrophages of rats immunized against rubeola virus].

Peritoneal macrophages in rats with no immunization against rubella virus and inoculted with bovine infectious rhinotracheitis virus are prone to suffer from a cytopathogenic effect with formation of inclusion bodies, and lysis, succeeding in reisolating the virus. The resistance of peritoneal macrophages of rats inoculated against rubella virus in nonspecific, since such resistance continues to show when macrophages interact with bovine infectious rhinotracheitis virus. The results support evidence that in the Inflammatory process suffered by rubella virus-inoculated rats, a cell immunity develops and macrophages are some of the cells performing the response.

Animals↗
PubMedDate not supplied

[In vitro study of the interaction of rubeola virus with the peritoneal macrophages of unimmunized and immunized rats].

In vitro peritoneal macrophage cultures of rats with no immunization against rubella virus and inoculated with these viral agents are prone to permit its intracellular proliferation and suffer a cytopathogenic effect and lysis. Peritoneal macrophages of immune rats do not permit intracellular proliferation and prevent harmful viral action. In the in vivo studies, peritoneal macrophages of non-immune rats eventually show a resistance to rubella virus during the infection. Our results suggest that macrophages require the co-operation of other elements involved in the living animal immunity in order to show resistance to rubella virus.

Animals↗
PubMedDate not supplied

Inhibition of small intestinal motility by casein: a role of beta casomorphins?

Several aspects on the effect of nutrients on small intestinal motility are not completely understood. We have analyzed changes of motor activity of the canine small bowel following intragastric administration of casein and soy protein. Studies were performed by intraluminal manometry with external transducers and multiple infused catheters with closely spaced registrating sites. Casein was followed by a statistically significant decrease of amplitude and frequency of small intestinal contractions, compared to soy protein. Pretreatment with naloxone suppressed the inhibitory effect of casein, suggesting that stimulation of opioid receptors by beta casomorphins, a product of digestion of casein, might be involved in the motility changes observed.

Animals↗
PubMedDate not supplied

[Localization of brain electric sources in patients with focal epilepsy].

In this paper we discuss a non-invasive method to localize neural electrical sources using EEG data. In this method, the human head is modelled by a set of four concentric spheres with different conductivities which represent the scalp, the skull, the CSF and the brain or by three triangulated surfaces which approximate the exact head shape (in this model we do not consider the CSF layer) using NMR images. In this case the computer effort is very high, since the calculations imply thousands of equations. Therefore, the number of research groups working with this improved model, in the world, is very small. In both models, we assume that the neural source is a current dipole. This makes the model suitable for cases where the active brain areas are limited and localized. We discuss some error factors associated with the method, as the geometry of the head, the conductivity of the different layers and the number of electrodes used in the EEG measurements. Comparing the more realistic head model, with the spherical one we often have differences of 1-2 cm. However, we can reach even more pronounced differences in the frontal areas. Concerning the skull conductivity, we realized that it could introduce errors of 1-2 cm. We observed that at least 50 electrodes should be used only since 21 electrodes could imply errors of about 0.5 cm. The method was applied, both in the spherical version and the realistic one, to clinical cases of focal epileptic patients. The results are discussed in terms of the other clinical information available and they are coherent with the remaining clinical data.

Adolescent↗
PubMedDate not supplied

[Evaluation of the Cell-DYN 35))].

The Cell-Dyn 3500 is an automated haematology analyzer which quantitatively measures and computes haematological quantities including a full "five-part" white cell differential. It measures 22 parameters for erythrocytes, white blood cells and platelets, also giving the respective histograms. Evaluation of the Cell-Dyn 3500 was performed according to the International Committee for Standardization in Haematology (ICSH) norms, for a period of 5 weeks. A total of 1,235 samples were studied by comparison with the Coulter MaxM. The five-part white cell differential and the flagging system were estimated and compared with the smear examination of 506 samples, by four clinical pathologists trained in cytology. Good correlation was obtained within, between batches, and day-to-day, for the following parameters: red blood cells (RBC), haemoglobin (HGB), mean cell volume (MCV), white blood cells (WBC) and platelets (PLT). The accuracy was estimated (RBC, HGB, VGM, WBC and PLT) each day with three different levels of titrated controls with good results. The linearity was established for RBC, HGB, WBC and PLT. The results obtained were good. Carry-over studies were performed according to the Broughton method for the same parameters and the results were also good. Stability studies for the automatic parameters including the differential white blood cell count showed that these parameters were stable at 4 degrees C for 48 hours. At room temperature the stability was reduced to 7 hours. Agreement was good between the Cell-Dyn 3500 and the Coulter MaxM, for the automatic haemocytometric values. The comparative studies between the five-part white cell differential of the haematologic analyzer and the manual differential showed excellent results for neutrophils and lymphocytes, very good for monocytes and eosinophils. For the flag estimation two criteria were established, one based on the clinical significance and the other based on the alarm detection described in the analyzer manual. The specificity was good for both criteria. In general the sensibility was better for the second criteria. The Cell-Dyn 3500 has thus shown to be a good haematology analyser which greatly reduces the morphological examination of smears.

Blood Cell Count↗
PubMedDate not supplied

Plasma concentration and brain penetration of the H3-receptor antagonist thioperamide in rats.

Thioperamide is a potent and selective H3-receptor antagonist, whose in vivo effects have been reported after systemic administration. Some questions have arisen about its ability to cross the blood-brain barrier, since different experimental conditions have given different results in rats, namely a low brain/blood ratio at low doses (10 mg/Kg) and a much higher one at higher doses (60 mg/Kg). In this work we demonstrate the dose-dependence of thioperamide pharmacokinetics, measuring its plasma and cerebral levels after i.p. administration of different doses to rats. Both the plasma half-life and brain penetration of thioperamide resulted as being dose-dependent: when administered to 80 g body weight Wistar rats at 10 mg/Kg i.p., the drug has a short half life (120') and a rather poor brain penetration, but increasing the dose (to 20, 40 and 60 mg/Kg) gives rise to a prolongation of its persistence in the blood (up to 600' at highest dose) and a higher brain penetration. Also, the profile of the plasma concentration curve varies from the dose of 10 to that of 20 mg/Kg, passing from a mono-exponential decrease to a more complex one characterized by an apparent distribution phase. The different distribution processes can be interpreted in the light of thioperamide protein binding and affinity for lipophilic tissues: protein binding can prevent brain penetration (but not distribution to other tissues) at lower doses, while at higher doses the free plasma fraction increases and it can allow passive distribution to lipophilic tissues such as brain tissues. A re-distribution from these tissues and plasma is probably responsible for the strong increase in half-life at high doses.

Animals↗
PubMedDate not supplied

In vitro characterization of potency, affinity and selectivity of H3-antagonists: from thioperamide to thioperamide unrelated imidazole derivatives.

This paper summarizes the findings obtained for three different series of original compounds designed as potential H3-antagonists starting from thioperamide structure. The compounds were tested in functional and binding assays to estimate their potency, affinity and selectivity for histamine H3 receptors. Among them, many non-thiourea/isothiourea derivatives acted as selective H3 competitive antagonists and, particularly, 4(5)-[2-[4(5)-cyclohexylimidazol-2-ylthio]ethyl] imidazole (dIII) proved to be the most potent H3 blocker vs (R)-alpha-methylhistamine in electrically-stimulated ileum. This imidazole derivative, devoid of thiourea dependent toxic effects, with high affinity displaced biphasically [3H]-N alpha-methylhistamine bound to rat brain H3 sites. Thus, such compound could be proposed as the prototype molecule for the development of new non-thiourea/isothiourea H3-antagonists and as experimental tool to explore the intriguing question of H3 receptor heterogeneity.

Animals↗