Chilean Consumer Law and Policy: A Brief Outlook

Chilean consumer law and policy has a short but enthralling history. As compared with other jurisdictions such as EU countries, its bedrock is still in formation, particularly pertaining to its envisaged role in the regulatory spectrum applicable to consumer markets. However, this circumstance has not been a serious obstacle to several reforms carried out in recent years aimed at broadening its scope of action, including rethinking a proposal regarding the policy goals to be addressed by the national consumer agency, SERNAC. In that context, this article presents a brief account of the main features of Chilean consumer law, considering the current socioeconomic development level of the country, the main pieces of legislation concerning consumer protection in the Chilean legal framework-notably the Chilean Consumer Protection Act-as well as key elements of the public policy approach in this matter. A few examples of topics such as product liability and sale and purchase of consumer goods are also analysed in order to allow a comparison of the Chilean experience in consumer protection with other jurisdictions.

What has changed during the state of emergency due to COVID-19 on an Academic Urology Department of a Tertiary Hospital in Portugal

Objetivo

Comparar la actividad del Servicio de Urología de un Hospital Universitario Portugués durante el estado de alarma y el periodo equivalente del año anterior. Comparamos el número de consultas electivas y pruebas diagnósticas urológicas, el número y el tipo de cirugías electivas, así como las características demográficas de los pacientes y las principales causas de ingreso al Servicio de Urgencias (SU) de Urología durante los dos periodos mencionados.

Materiales y métodos

Los datos de 691 pacientes que acudieron a urgencias desde el 18 de marzo de 2020 hasta el 2 de mayo de 2020 -y del mismo periodo del año anterior- se recogieron del software medico institucional. Los datos recopilados fueron edad, sexo, fecha de visita al servicio de urgencias, derivación desde otros hospitales, color del triaje, causa del ingreso, diagnóstico al alta y la necesidad de cirugía de urgencia u hospitalización. Con la intención de identificar las asociaciones entre las variables demográficas y clínicas con el hecho de haber sido sometido a una cirugía de urgencia (variable), se aplicaron modelos de regresión logística.

Resultados

El análisis multivariante mostró asociación entre el sexo del paciente con el hecho de ser sometido a una cirugía, con una disminución del 65,6% en las probabilidades para el género masculino. El periodo (COVID versus sin-COVID) no mostró una asociación significativa con la cirugía.

Conclusión

Nuestro departamento experimentó una reducción importante en la actividad. También observamos una reducción de las causas urgentes para acudir a los servicios de urgencias considerados menos graves. El porcentaje de casos que requirieron cirugía de urgencia y hospitalización fue mayor durante el periodo COVID.

International validation of the European Organisation for Research and Treatment of Cancer QLQ-BRECON23 quality-of-life questionnaire for women undergoing breast reconstruction

Background

The aim was to carry out phase 4 international field-testing of the European Organisation for Research and Treatment of Cancer (EORTC) breast reconstruction (BRECON) module. The primary objective was finalization of its scale structure. Secondary objectives were evaluation of its reliability, validity, responsiveness, acceptability and interpretability in patients with breast cancer undergoing mastectomy and reconstruction.

Methods

The EORTC module development guidelines were followed. Patients were recruited from 28 centres in seven countries. A prospective cohort completed the QLQ-BRECON15 before mastectomy and the QLQ-BRECON24 at 4–8 months after reconstruction. The cross-sectional cohort completed the QLQ-BRECON24 at 1–5 years after reconstruction, and repeated this 2–8 weeks later (test–retest reliability). All participants completed debriefing questionnaires.

Results

A total of 438 patients were recruited, 234 in the prospective cohort and 204 in the cross-sectional cohort. A total of 414 reconstructions were immediate, with a comparable number of implants (176) and donor-site flaps (166). Control groups comprised patients who underwent two-stage implant procedures (72, 75 per cent) or delayed reconstruction (24, 25 per cent). Psychometric scale validity was supported by moderate to high item-own scale and item-total correlations (over 0·5). Questionnaire validity was confirmed by good scale-to-sample targeting, and computable scale scores exceeding 50 per cent, except nipple cosmesis (over 40 per cent). In known-group comparisons, QLQ-BRECON24 scales and items differentiated between patient groups defined by clinical criteria, such as type and timing of reconstruction, postmastectomy radiotherapy and surgical complications, with moderate effect sizes. Prospectively, sexuality and surgical side-effects scales showed significant responsiveness over time (P < 0·001). Scale reliability was supported by high Cronbach's α coefficients (over 0·7) and test–retest (intraclass correlation more than 0·8). One item (finding a well fitting bra) was excluded based on high floor/ceiling effects, poor test–retest and weak correlations in factor analysis (below 0·3), thus generating the QLQ-BRECON23 questionnaire.

Conclusion

The QLQ-BRECON23 is an internationally validated tool to be used alongside the EORTC QLQ-C30 (cancer) and QLQ-BR23 (breast cancer) questionnaires for evaluating quality of life and satisfaction after breast reconstruction.

Neuroprotective and Therapeutic Strategies for Manganese-Induced Neurotoxicity

Manganese (Mn) is an essential element required for growth, development and general maintenance of health. However, chronic or high occupational and environmental exposure to excessive levels of Mn has long been known to lead to a progressive neurological disorder similar to Parkinsonism. Manganism patients display a variety of symptoms, including mental, cognitive and behavioural impediments, as well as motor dysfunctions that are associated with basal ganglia dysfunction. Taking into account the pharmacokinetics and Mn-related toxicity mechanisms, several neuroprotective compounds and therapeutic approaches have been investigated to assess their efficacy in mitigating its neurotoxicity. Here, we will briefly address some of the toxic mechanisms of Mn, followed by neuroprotective strategies and therapeutic approaches aiming to reduce or treat Mn induced neurotoxicity. Natural and synthetic antioxidants, anti-inflammatory compounds, ATP/ADP ratio protectors and glutamate protectors have been introduced in view of decreasing Mn-induced neurotoxicity. In addition, the efficacy and mechanisms of several therapeutic interventions such as levodopa, ethylene-diamine-tetraacetic acid (EDTA) and para-aminosalicylic acid (PAS), aimed at ameliorating Mn neurotoxic symptoms in humans, will be reviewed.

A high-fat plus fructose diet produces a vascular prostanoid alterations in the rat

In the rat, a high-fat (HF) plus fructose (F) diet produces cardiovascular and metabolic alterations that resemble human metabolic syndrome. Prostanoids (PR), cyclo-oxygenase-derived arachidonic acid metabolites, have vasoactive properties and mediate inflammation. The aim of this study was to analyse the effect of a HF+F diet on blood pressure (BP), metabolic parameters and mesenteric vascular bed PR production in male Sprague-Dawley rats. Four groups were studied over 9 weeks (n = 6 each): control (C), standard diet (SD) and tap water to drink; F+SD and 10% w/v F solution to drink; HF 50% (w/w) bovine fat added to SD and tap water; and HFF, both treatments. PR were determined by HPLC. Blood pressure was elevated in all experimental groups. Triglyceridaemia, insulinaemia and HOMA-IR were increased in the F and HF groups. HF+F animals showed elevated glycaemia, insulinaemia, HOMA-IR and triglyceridaemia. F decreased the vasodilator prostanoids PGI2 and PGE2 in the mesenteric vascular bed. Body weight was not significantly altered. In HFF, production of PGE2 , PGF2 alpha and TXB2 was elevated. The increased BP in HF and HFF could be partly attributed to the imbalance in vascular PR production towards vasoconstrictors. On the other hand, this dietary modification could induce inflammation, which would explain the elevation of PGE2 . In the F group, hypertension could be related to decreased vasodilator PRs. The simultaneous administration of HF and F in the rat produces deleterious effects greater than observed when treatments are applied separately.

Arsenic and manganese alter lead deposition in the rat

Lead (Pb) continues to be a major toxic metal in the environment. Pb exposure frequently occurs in the presence of other metals, such as arsenic (As) and manganese (Mn). Continued exposure to low levels of these metals may lead to long-term toxic effects due to their accumulation in several organs. Despite the recognition that metals in a mixture may alter each other's toxicity by affecting deposition, there is dearth of information on their interactions in vivo. In this work, we investigated the effect of As and Mn on Pb tissue deposition, focusing on the kidney, brain, and liver. Wistar rats were treated with eight doses of each single metal, Pb (5 mg/Kg bw), As (60 mg/L), and Mn 10 mg/Kg bw), or the same doses in a triple metal mixture. The kidney, brain, liver, blood, and urine Pb, As, and Mn concentrations were determined by graphite furnace atomic absorption spectrophotometry. The Pb kidney, brain, and liver concentrations in the metal-mixture-treated group were significantly increased compared to the Pb-alone-treated group, being more pronounced in the kidney (5.4-fold), brain (2.5-fold), and liver (1.6-fold). Urinary excretion of Pb in the metal-mixture-treated rats significantly increased compared with the Pb-treated group, although blood Pb concentrations were analogous to the Pb-treated group. Co-treatment with As, Mn, and Pb alters Pb deposition compared to Pb alone treatment, increasing Pb accumulation predominantly in the kidney and brain. Blood Pb levels, unlike urine, do not reflect the increased Pb deposition in the kidney and brain. Taken together, the results suggest that the nephro- and neurotoxicity of "real-life" Pb exposure scenarios should be considered within the context of metal mixture exposures.

Physiological quality and gene expression related to heat-resistant proteins at different stages of development of maize seeds

We quantified and characterized the expression of heat-resistant proteins during seed development of maize lines with distinct levels of tolerance to high drying temperature. A corn field was planted for multiplication of seeds of different lines, two tolerant and two non-tolerant to high drying temperatures. Harvest of the seeds was carried out at various stages of development and they were then subjected to tests of moisture content, germination, first count of germination, accelerated aging, and cold test. The seeds were stored in a freezer for later analysis of expression of heat-resistant proteins by means of real-time PCR, electrophoresis, and spectrophotometry. We observed that heat-resistant proteins are expressed in a differential manner in seeds from different lines and at different stages of development. The expression of heat-resistant proteins was earlier in lines tolerant to high drying temperatures. Greater germination and vigor values was found for seeds collected at the last stage of development.

Sodium molybdate prevents hypertension and vascular prostanoid imbalance in fructose-overloaded rats

(1) Fructose (F) overload produces elevated blood pressure (BP), hyperglycaemia, hypertriglyceridemia and insulin resistance, resembling human metabolic syndrome. Previously, we found altered vascular prostanoid (PR) production in this model. (2) Sodium molybdate (Mo), as well as sodium tungstate, causes insulin-like effects and normalizes plasma glucose levels in streptozotocin-treated diabetic rats. We studied the effects of Mo on BP, metabolic parameters and release of PR from the mesenteric vascular bed (MVB) in F-overloaded rats. (3) Four groups of male Sprague-Dawley rats were analysed: Control, tap water to drink; F, F solution 10% W/V to drink; CMo, Mo 100 mg kg day(-1) and FMo, both treatments. After 9 weeks, the animals were killed and MVBs removed and the released PRs measured. (4) F increased BP, glycemia, triglyceridemia and insulinemia. Mo treatment prevented the increases in BP and glycemia, but did not modify triglyceridemia or insulinemia. In addition, Mo decreased BP in controls. (5) Prostaglandins (PG) F2 alpha and E2, PG 6-ketoF1 alpha and thromboxane (TX) B2 , as well as inactive metabolites of prostacyclin (PGI2 ) and TXA2 were detected. F decreased the production of vasodilator PRs PGI2 and PGE2 in MVB. Mo prevented these alterations and increased PGE2 in controls. Vasoconstrict or PRs PGF2 alpha and TXA2 release was not modified. (6) Mo treatment, beyond its known lowering effect on glycemia, prevents the reduction in the vascular release of vasodilator PR observed in this model. This could be one of the mechanisms by which Mo avoids the increase in BP caused by F overload in the rat.

Abstract PD05-02: Novel mutations in lobular carcinoma in situ (LCIS) as uncovered by targeted parallel sequencing

Background: LCIS has traditionally been recognized as a marker of increased risk for the subsequent development of breast cancer, of either the lobular or ductal phenotype, yet due to the incidental nature of LCIS little is known about its underlying biology. Here we describe the first report of novel mutations in LCIS using targeted exome sequencing of fresh frozen tissue samples.

Methods: Fresh frozen tissue samples from patients with a prior history of LCIS undergoing therapeutic or risk-reducing mastectomy from 2003–08 were harvested and systematically reviewed to identify LCIS. Cells from individual LCIS lesions +/− associated cancers were collected by laser capture microdissection. For the purposes of this study, germline DNA (blood) and DNA from 12 unique LCIS lesions were subject to targeted parallel sequencing of exons corresponding to 230 cancer genes using the Illumina HiSeq 2000 platform. DNA from an associated ductal carcinoma in situ (DCIS) and/or an invasive ductal (IDC) or lobular (ILC) lesion was also available for 7 of these cases resulting in 41 samples from 12 pts for mutational analysis. Normalized (RMA) Affymetrix U133A gene expression data were also available.

Results: DNA profiling reliably identified 7 somatic mutations in 5/12 LCIS samples (41.7%). Of these, 4/7 mutations were base substitutions (missense mutations); and the others included: 1 deletion; 1 silent and 1 splice-site mutation. Mutations in LCIS were identified in 5/230 cancer genes analyzed, including: PIK3CA, CDH1, NOTCH4, PREX2 and ARAF. PIK3CA and CDH1 mutations were each identified in two samples, representing 4/7 (57.1%) mutations. Specific mutations found in LCIS and their frequencies are listed (table). Among 3 LCIS-ILC pairs, one shared the G914R mutation in PIK3CA, and 1/3 LCIS-IDC pairs exhibited an identical point mutation (R373W) in the NOTCH4 gene. No shared mutations were observed in 3 LCIS-DCIS pairs. Both CDH1 mutated cases were associated with decreased e-cadherin mRNA levels when compared to non-mutated cases (mean 9.88 vs 11.01), as was the NOTCH4 mutation (mean 6.02 vs 6.47). Mutations in ARAF and PREX2 were associated with increased mRNA levels, mean 7.07 vs 6.52 and 4.82 vs 4.22, respectively. The hotspot PIK3CA mutation (E545K) was also associated with increased gene expression (mean 5.15 vs 4.64) whereas the G914R mutant was associated with decreased expression (mean 4.13 vs 4.64).

Abstract P4-06-07: PI3K Mutations Are More Common in Low Grade DCIS

Background: DCIS is a non-obligate precursor to invasive breast cancer yet it remains difficult to predict which lesions will progress or over what time interval. Factors associated with a higher risk of progression include high histologic grade and HER2 amplification. HER2 signaling via the PI3K pathway is associated with accelerated invasiveness in laboratory models and mutations in the helical domain of PI3K have been associated with a worse prognosis in invasive cancer. We hypothesized that PI3K pathway mutations are associated with higher risk of progression in DCIS and therefore would be more common in high grade DCIS.

Methods: 195 cases of pure DCIS were identified from the MSKCC breast service database (1999-2003). All cases were reviewed by a single pathologist to assign histologic grade. Sections were obtained from archived formalin-fixed paraffin embedded (FFPE) blocks for manual microdissection to isolate pure DCIS lesions for DNA extraction. Multiplex array (Sequenom®) genotyping for PIK3CA was performed on prePCR amplified DNA. Comparisons were made between high and low grade DCIS using Fisher's exact test.

Results: Among 195 pure DCIS cases, 89 were classified as high grade and 106 as low grade. Sequenom® analysis was informative in all cases. PIK3CA mutations were identified in 4/89 (4%) cases of high grade DCIS and in 24/106 (23%) cases of low grade DCIS (p=0.000). All 4 mutations in high grade DCIS were located in the kinase domain, whereas in low grade DCIS, 9/24 (37%) mutations were in the kinase domain (H1047R) and 15/24 (67%) mutations were in the helical domain (E542K, E545K, N345K).

Conclusion: PI3K mutations were relatively uncommon in pure high grade DCIS as compared to low grade DCIS. PI3K mutations in low grade DCIS were observed in both the kinase and helical domain. These findings support the hypothesis that breast tumorigenesis differs by grade and PI3K mutations may be more prominent in low grade carcinogenesis. The significance of helical domain mutations in low grade lesions requires further investigation.

Mapping of quantitative trait locus associated with maize tolerance to high seed drying temperature

quantitative trait locus (QTL) mapping and identification of traits of agronomic importance is important in the process of molecular marker-assisted selection in breeding programs. The molecular map of maize is well saturated and QTL and simple sequence repeat (SSR) markers have been identified, whereas few markers linked to seed quality traits are included. The present study aimed to identify QTL and the gene action and to quantify the effects of these regions in the phenotypic variation related to maize tolerance to high seed drying temperature. SSR markers and 129 segregating families of F2 plants of the cross of intolerant and tolerant lines were used in regression and composite interval mapping methods. Three maize QTL associated with tolerance to high seed drying temperature were identified and mapped to chromosomes 6 and 8, explaining 39% of the phenotypic variation of the trait with additive, dominance and overdominance gene action. These markers seem to be effectively associated with the evaluated trait, since all were mapped near genes whose expression products were associated with seed desiccation tolerance.

Secular trends of new leprosy cases diagnosed in Brazil during 1987-2006

OBJECTIVE

To analyze trends in occurrence of new leprosy cases in Brazil in the light of changes in public health policy during the period 1987-2006.

MATERIAL AND METHODS

Study of secular trends in New case detection rate (NCDR), viz. for leprosy in Brazil between 1987 and 2006. A linear trend was used to analyze separately the detection rate during the two decades 1987-1996 and 1997-2006. The cut-off point was the year with the peak detection rate in 1997. To analyze the potential increase in accessibility to diagnosis and treatment, a comparison was made between the proportion of cases diagnosed within the health services and municipalities over a 20-year period, split into four 5-year intervals.

RESULTS

The variation of the NCDR between 1987 and 2006 more than doubled between 1987 and 1997, decreased from 1997 to 2000, increased up to 2003 and then dropped considerably between 2004 and 2006. The number of facilities providing health services for the 5-year periods showed a marked increase-more than doubling between the second and third and between the third and fourth periods. The number and therapeutic services are indications that Brazil is perhaps making considerable progress towards eliminating leprosy as a public health problem.

Motor neuron disease associated with non-fluent rapidly progressive aphasia: case report and review of the literature

The superimposed clinical features of motor neuron disease (MND) and frontotemporal lobar degeneration (FTLD) comprise a rare neurological overlap syndrome that represents a diagnostic challenge to neurologists. Currently, FTLD-MND is considered a distinct entity and its clinicopathological basis has recently been reviewed. Our aim is to present a patient with MND and non-fluent rapidly progressive aphasia with clinical, imaging and histopathological correlation, as well as a brief review of the literature. We demonstrated the selective corticospinal tract (CST) and temporal lobe involvement using T1 spin-echo with an additional magnetization transfer contrast pulse on resonance (T1 SE/MTC) and FLAIR MR sequences in our patient, with further clinical and histopathological correlation. To the best of our knowledge, there is no description about the use of these particular MR sequences in the evaluation of FTLD-MND patients.

Erdheim?Chester disease of the breast associated with Langerhans-cell histiocytosis of the hard palate

We report a patient with Langerhans-cell histiocytosis (LCH) localized to the hard palate that was later proven to be associated with Erdheim-Chester disease (ECD), involving the right breast, skeleton, retroperitoneum and left orbit. The diagnosis was based on the symmetric osteosclerosis of the long bones diaphyses (tibias and fibulas), breast lump histopathological/immunohistochemical findings and retroperitoneum and left orbit images in magnetic resonance. Mammary involvement by ECD is an extremely rare condition, which should be differentiated from some benign and malignant mimickers, especially the histiocytoid type of breast carcinoma. Characteristic histological features plus clinical and radiographic information are needed to achieve a correct diagnosis. The ECD, its relation to the LCH and details of the breast lesion are discussed.

Catastrophic bifurcation from riddled to fractal basins

Most existing works on riddling assume that the underlying dynamical system possesses an invariant subspace that usually results from a symmetry. In realistic applications of chaotic systems, however, there exists no perfect symmetry. The aim of this paper is to examine the consequences of symmetry-breaking on riddling. In particular, we consider smooth deterministic perturbations that destroy the existence of invariant subspace, and identify, as a symmetry-breaking parameter is increased from zero, two distinct bifurcations. In the first case, the chaotic attractor in the invariant subspace is transversely stable so that the basin is riddled. We find that a bifurcation from riddled to fractal basins can occur in the sense that an arbitrarily small amount of symmetry breaking can replace the riddled basin by fractal basins. We call this a catastrophe of riddling. In the second case, where the chaotic attractor in the invariant subspace is transversely unstable so that there is no riddling in the unperturbed system, the presence of a symmetry breaking, no matter how small, can immediately create fractal basins in the vicinity of the original invariant subspace. This is a smooth-fractal basin boundary metamorphosis. We analyze the dynamical mechanisms for both catastrophes of riddling and basin boundary metamorphoses, derive scaling laws to characterize the fractal basins induced by symmetry breaking, and provide numerical confirmations. The main implication of our results is that while riddling is robust against perturbations that preserve the system symmetry, riddled basins of chaotic attractors in the invariant subspace, on which most existing works are focused, are structurally unstable against symmetry-breaking perturbations.

Monitoring the elimination of leprosy in Brazil

A decreasing trend in the prevalence rate of leprosy was reached in Brazil only after the introduction of the World Health Organization multidrug therapy (WHO/MDT) program in 1990. This paper analyzes leprosy morbidity indicators and the prevalence rate, and their utilization in monitoring the progress of leprosy elimination in Brazil. Since these indicators are modified by changes in health service procedures, comparing prevalence rates from different endemic countries or current prevalence rates with old ones from the same endemic region needs careful attention. The current official prevalence rate of 6.72/10,000 inhabitants in Brazil could be considered high when compared with rates from other countries, but it is important to remember that defaulters and patients being treated with old regimens are kept on the active registers in Brazil, while in most other endemic countries they are not.

[Follow-up of nurses who have finished the specialization courses in intensive care nursing]

The purpose of this study was to analyse the contribution of the Extension Courses in the Intensive Care held at the Nursing School from USP, with the aim to: 1) Follow up nurses in their work at the ICU. 2) Evaluate the contribution offered by the course. The population was formed by 38 nurses, considering that 60.5% didn't work in the ICU anymore mainly because they assumed another function in the institution and had several private problems. Regarding the contribution offered by the course, the main evaluation was the acquirement of knowledge (91.7%). However, 74.2% of the nurses declared the course didn't contribute to the increase of their wage, what do not impair them from investing in their professional improvement.

The importance of operational factors for the interpretation of indicators in the Hansen's disease endemic in Brazil

In Brazil, an increase has been recorded in recent years in the magnitude of detection coefficients for new cases of Hansen's disease, which is frequently interpreted as evidence of the endemic's expansion. The objective of this work is the determine the role of operational factors for interpreting the trend displayed by the morbidity coefficients for Hansen's disease from 1982 to 1995 in the country. We observed a strong correlation between the adjusted detection coefficients and the number of technicians trained (r = 0.80), a decrease in the proportion of new cases with disabilities at the time of diagnosis (r = 0.86), and a downward trend in tuberculoid forms (r = -0.70). Patient time on the active register is correlated negatively with MDT-WHO coverage (r = -0.95) and the percentage of patients discharged from treatment due to cure (r = -0.91). These results suggest that the increase in the potential for detection of new cases of Hansen's disease resulting from new strategies adopted by the program, i.e., mainly extensive training of health personnel, could be a coherent explanation for the increase in detection coefficients for new cases observed in Brazil in the last ten years.

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.

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.

Immunological response of Swiss mice to infection with three different strains of Trypanosoma cruzi

The immunological response of Swiss mice to infection with three strains of Trypanosoma cruzi which differ in their morphobiological, antigenic and isoenzymic characters [Peruvian, 12 SF (São Felipe) and Colombian strains] was investigated. The three strains stimulated an elevation of the immunoglobulin fractions IgG2a, IgG2b and IgM during acute infection, as measured by radial immunodiffusion, and an early drop of IgG1 levels. There were low levels of specific antibodies and a negative cutaneous delayed hypersensitivity test to T. cruzi antigens. Cellular reaction of the spleen was evident, with proliferation of lymphocytes and the presence of blastic lymphoid cells in the red and white pulp, and hyperplasia of germinal centres of the lymphoid follicles. Those aspects were consistent with a depletion of the T-cell zone (periarteriolar lymphocyte sheath). Despite these common features, there were clear differences in the onset, intensity and evolution of the splenic cellular reaction and IgG serum levels and in the relationship between these levels and parasitaemia in the mice infected with the three strains of T. cruzi. A positive correlation was seen between high IgG levels and mortality, corresponding to intense exudative tissue lesions, showing that a raised immunoglobulin level was not associated with protection. It is worth observing that the 12 SF strain, which showed the lowest parasitaemic profile and mortality rate, stimulated the greatest elevation of IgG2b during acute infection; and also that IgG2a and IgG2b were the immunoglobulins which showed the greatest increases following infection by all three strains of T. cruzi.

[Immunological aspects of infection of 6 inbred strains of mice by 3 different strains of Trypanosoma cruzi]

We evaluated humoral and cellular immune responses in 6 inbred mouse strains (BALB/c, B-10, C3H, A/J, AKR and DBA) infected with 3 Trypanosoma cruzi strains (Peruvian, 21 SF and Colombian), which are the standards for the 3 strains Types of Andrade's classification. Negative delayed-type hipersensitivity reactions to parasite antigens were evidence of suppressed cell-mediated immunity. An early drop of IgG1 and rise of IgM levels were observed in almost all mouse strains infected by any T. cruzi strain. Elevation of IgG2a and/or IgG2b levels was higher in resistant mouse strains. Anti-T. cruzi antibody levels (Indirect immunofluorescence and ELISA) did not correlate with survival. Despite some differences among mouse strains there was a definition of an overall pattern of host response and the maintenance of biological standards which characterize the basic types of T. cruzi strains.

Correlation between isoenzyme patterns and biological behaviour of different strains of Trypanosoma cruzi

Three strains of Trypanosoma cruzi, used previously as prototypes for a classification based on the host-parasite relationships, as well as several stocks isolated from different geographical areas in Brazil, were submitted to isoenzymic analysis. Their isoenzyme patterns revealed a clear correlation with the biological data. The patterns obtained with the enzymes PGM, GPI, ASAT and ALAT permitted discrimination between each of the described types. Only one type was found in each geographical area studied, indicating a possible relationship between regional patterns and clinical presentation of Chagas' disease.