Exposure to PM2.5 and cardiovascular diseases in Portugal – the contribute of PMCardImpact project

 

Particulate matter with a diameter of 2.5 μm or less (PM2.5) are one of the air pollutants more detrimental to human health, being responsible for around 400 000 premature deaths in Europe every year. The cardiovascular diseases (CVD) and air pollution are linked, with existing evidence of a causal relationship between exposure to particulate matter and cardiovascular morbidity and mortality. Under the scope of PMCardImpact, a national funded project, data collected from Portuguese air monitoring platform (2005-2021) (>60 stations) was used to estimate the attributable number of cases of acute myocardial infarction. The air monitoring data and parameters such as exposure-response factors will support the risk assessment in AirQ+ software (WHO Regional Office for Europe). Preliminary results showed that exceedances of Air Quality Directive in Portugal ranged between 0.1 % and 10.2% for PM10 and PM2.5 in 2019. Results obtained will include the number of cases of CVD attributable to exposure to PM2.5 in the Portuguese population. Four scenarios of exposure will be considered for presenting the results: current scenario of exposure, new WHO Air Quality guidelines, European Commission Air Quality Directive and lastly, a worst-case scenario. This assessment will be the starting point for calculation of the burden of disease of CVD that exposure to PM2.5 represent in Portugal. With a view to promote the science to policy interface, PMCardImpact project will make available to policy makers the needed supporting information to act, including actionable knowledge on air pollution trends and related health effects, to implement reducing air pollution policies.

This work is funded by FCT/MCTES through national funds to PMCardImpact (EXPL/SAU-PUB/0944/2021) and CESAM (UIDP/50017/2020 + UIDB/50017/2020 + LA/P/0094/2020).

Key messages

• PMCardImpact will make available to policy makers the needed supporting information to act to implement reducing air pollution policies.

• Risk assessment will allow to determine the number of CVD cases attributable to air pollution.

Evaluation of Clinical Trials in Onco-haematology: A New Method Based on Risk Analysis and Multidisciplinarity

BACKGROUND

European member states are increasingly vying with one another to recruit patients for clinical trials (CTs). The French national agency for medicines (ANSM) now receives an ever-growing number of CTs, extending response times. The aim of the new methodology presented herein is to reduce assessment times below the national mandatory timeframe of 60 days and to improve patient safety.

MATERIALS AND METHODS

Based on an analysis of the criteria defining CTs, 4 key points were identified (safety, fragile population, loss of opportunity, design complexity) to build a criticality score which would determine evaluation type. This score also determines the resources needed (complete evaluation, multidisciplinary advice, ad hoc evaluation) and the timeframe required for appropriate analysis. All post-phase I CTs were analysed from the implementation of the new assessment method, on 01/02/2018 through to 31/12/2019.

RESULTS

447 CTs were analysed (63% industry and 37% academic sponsors). Based on a criticality scale, 27% of the CTs received a type A evaluation (complete), 37% a type B (multidisciplinary evaluation), 23% a type C evaluation (ad hoc evaluation) and 13% a type D evaluation (fast evaluation). From 2014 to 2017, 37% of the CTs were analysed within the mandatory timeframe, with a mean of 68 days, reaching a maximum of 102 days in 2017. Using this new assessment method, 92% of CTs respected the mandatory timeframe in 2019; the mean time in 2018-2019 was 34 days; Grounds for Non-Acceptance (GNA) were raised for 66% of the CTs (69% from academic sponsors and 65% from industrial firms). 3 CTs were refused.

CONCLUSION

Here, we demonstrate the feasibility of risk analysis and multidisciplinarity method, which resulted in a dramatic improvement of assessment times.

Assessing fitness to drive: Knowledge and practices from medical doctors and psychologists

Introduction Medical and psychological assessment of fitness to drive is a professional activity performed in a large number of candidates and drivers to validate a driving license. Medical doctors and psychologists are responsible to assess medical and psychological abilities for driving, respectively. Despite the legal framework for assessing fitness to drive on each country, the knowledge and practices among professionals may vary.

Objectives To examine the knowledge and practices of Portuguese medical doctors and psychologists concerning the assessment of fitness to drive.

Methodology Two online questionnaires, one version for medical doctors and another for psychologists, were designed to measure self-reported knowledge and practices towards assessment of fitness to drive. The questionnaires were disseminated by e-mail to a non-probability sample, responding 273 participants, including 128 medical doctors and 145 psychologists.

Results In the sample of medical doctors, 49% recognized themselves as not qualified to do a medical assessment of fitness to drive, 40% reported lack of knowledge about the related legislation and the majority (83%) feel that would benefit from further education in this area. Concerning psychologists, 52.4% judged themselves as not qualified for psychological assessment for driving, 49.7% recognized lack of knowledge about the legislation and 70% would like to do training in this area. Both groups pointed lack of knowledge about several parameters such as mandatory assessments and periods, professional responsibilities and assessment methods.

Conclusion Medical doctors and psychologists highlighted lack of knowledge and confidence to practice assessments of fitness to drive. Academic education and training needs are pointed in order to improve the professional practices in those assessments with potential impact on road safety and public health.

Highly Sensitive Piezoresistive Graphene-Based Stretchable Composites for Sensing Applications

Nanocarbonaceous materials with specific geometries and physicochemical properties allow the development of high-performance polymer-based smart composite materials. Among them, chemical treatments of graphene allow tailoring its electrical conductivity and, therefore, tuning functional response of materials for sensing applications. Polymer-based nanocomposites have been developed from styrene-ethylene-butylene-styrene (SEBS), a high deformation thermoplastic elastomer, and different graphene-based fillers, including graphene oxide (GO), reduced graphene oxide (rGO), and graphene nanoplatelets (G-NPLs). It is shown that the electrical conductivity shows a percolation threshold around 2 wt % for GO and rGO, remaining nearly independent of the filler content for G-NPL filler contents up to 6 wt %. Furthermore, GO/SEBS and rGO/SEBS composites show high piezoresistive sensibility with gauge factors ranging from 15 up to 120 for strains up to 10%. Thus, GO/SEBS and rGO/SEBS composites can represent a new generation of materials for strain sensor applications, as demonstrated in their implementation in a hand glove prototype with finger movement monitoring.

Eritrocitose primária em cão: relato de caso

RESUMO A eritrocitose absoluta primária, também denominada de policitemia vera, é um distúrbio mieloproliferativo crônico de causa desconhecida, caracterizado pela proliferação clonal de células-tronco eritróides neoplásicas. Acomete cães de meia-idade entre seis e sete anos. As manifestações clínicas mais comuns são letargia, fraqueza, poliúria, polidipsia, sangramentos como epistaxe, hematúria, hematoemese, hematoquezia, até mesmo convulsões e ataxia. O diagnóstico é baseado em valores altos de hematócrito, geralmente acima de 70%, excluindo-se as causas de eritrocitose secundária. As concentrações séricas de eritropoietina estão normais ou diminuídas. O tratamento consiste em flebotomia e administração de hidroxiuréia. Relata-se o caso de uma cadela, raça Bichon Frise, 11 anos, que, no início do quadro, apresentou hematócrito de 84%, letargia, ataxia, mucosas congestas, cianose de língua, poliúria e polidipsia. Realizou-se o tratamento com hidroxiuréia durante oito anos, na dose de 15 a 30 mg/kg, a cada 24 horas, sem ocorrência de efeitos colaterais ou recidiva das manifestações clínicas.

Sensitive vs. tolerant Nitzschia palea (Kützing) W. Smith strains to atrazine: a biochemical perspective

Organic contaminants, and herbicides in particular, represent a risk for aquatic ecosystems. The primary target of herbicides are producers, the base of food webs, but frequently they end up far from the application point affecting non-target species. Its presence can work as sub-lethal stimulus, which sort the genetic and phenotypic differences within a species. Intraspecific variation allows adaptation to changes in the environment but also to new niches due to variations in species' sensitivity and biochemical response to a certain chemical. A better understanding of these variations can lead to the development of improved strategies for ecosystem protection. This research aimed to compare a sensitive and a tolerant strain of the freshwater diatom Nitzschia palea to atrazine. Strains were exposed to three concentrations within their tolerance range, during 96 h. The activity of the antioxidant enzymes superoxide dismutase, catalase, glutathione-S-transferases and glutathione peroxidases was determined. In addition, chlorophylls a and c, carotenoids, reduced glutathione, proteins and lipid peroxidation were quantified. Both strains displayed different strategies to deal with atrazine toxicity: while the sensitive strain decreased the oxidative stress, increasing the activity of antioxidant enzymes such as superoxide dismutase, the tolerant strain invested in conjugation pathways and carotenoids' maintenance.

Intake of different hays with presence of Colchicum autumnale by rabbits

<p>The ingestion of 3 hay types by growing rabbits and the consequences on animal performance were studied in a first part. Two kinds of hay from high nature value grasslands [CFP (<em>Colchico-Festucetum pratensis</em>) and SBR (<em>Senecioni-Brometum racemosi</em>)] differentiated by their botanical composition were compared to a classical agricultural hay (control). The 3 hays, offered <em>ad libitum</em>, were ingested at 30.6, 34.8 and 36.1 g/kg body weight (BW) respectively for SBR, CFP and the control, where the consumption of SBR hay was significantly lower. (P&lt;0.01). The type of hay distributed did not affect the consumption of commercial feed or growth (44 g/kg BW and 36 g/d, respectively). The effect of meadow saffron concentration (<em>Colchicum autumnale</em>) in CFP hay was tested at 3 doses (absence, 2.75 and 15% of the distributed hay mass) with respect to their effect on ingestion and animal health. Again, no effect of the presence of meadow saffron (MeS) in the hay on these parameters was observed, even at the highest dose. However, during this second part, rabbits preferred to consume meadow saffron instead of the rest of the distributed hay (hardly any MeS was refused by rabbits at the representative dose, whereas 12% of the rest of the hay was refused, and 3.4 and 20% respectively at the maximal dose). The intake of the toxic alkaloid colchicine corresponded to 30 to 44% of the median lethal doses (LD₅₀) at the representative and maximal doses respectively. The real exposure of the rabbits was probably lower, as the absorption of ingested colchicine is reported to be around 50% of the LD₅₀ values which are established after an intravenous injection. Nevertheless, the absence of any effect should be interpreted with caution. The colchicine content of MeS varied greatly depending on the time of harvest and the parts of the plant taken into consideration. A late harvest (mid-June or later) would ensure (very) low concentrations of colchicine in the aerial parts of MeS. The presence of cloves on this plant should be completely avoided, due to the very high concentration of colchicine in the seeds. Moreover, long term exposure of the animals to this toxic plant may increase the risk of adverse effects. The study shows that hay distribution can aid digestion without altering the animal’s performance. Moreover, the valorisation of hay from high nature value grasslands would not only add real value to the commercialisation of rabbit meat by commercial breeders, but also to pet owners on the condition that hay quality would be guaranteed.</p>

Metabotropic glutamate 5 receptor in the infralimbic cortex contributes to descending pain facilitation in healthy and arthritic animals

The involvement of the prefrontal cortex in pain processing has been recently addressed. We studied the role of the infralimbic cortex (IL) and group I metabotropic glutamate receptors (mGluRs) in descending modulation of nociception in control and monoarthritic (ARTH) conditions. Nociception was assessed using heat-induced paw withdrawal while drugs were microinjected in the IL of rats. Local anesthesia of the IL or the adjacent prelimbic cortex (PL) facilitated nociception, indicating that IL and PL are tonically promoting spinal antinociception. Phasic activation with glutamate (GLU) revealed opposing roles of the PL and IL; GLU in the PL had a fast antinociceptive action, while in the IL it had a slow onset pronociceptive action. IL administration of a local anesthetic or GLU produced identical results in ARTH and control animals. An mGluR5 agonist in the IL induced a pronociceptive effect in both groups, while mGluR5 antagonists had no effect in controls but induced antinociception in ARTH rats. Activation of the IL mGluR1 (through co-administration of mGluR1/5 agonist and mGluR5 antagonist) did not alter nociception in controls but induced antinociception in ARTH animals. IL administration of an mGluR1 antagonist failed to alter nociception in either experimental group. Finally, mGluR5 but not mGluR1 antagonists blocked the pronociceptive action of GLU in both groups. The results indicate that IL contributes to descending modulation of nociception. mGluR5 in the IL enhance nociception in healthy control and monoarthritic animals, an effect that is tonic in ARTH. Moreover, activation of IL mGluR1s attenuates nociception following the development of monoarthritis.

DJ-1 interactions with α-synuclein attenuate aggregation and cellular toxicity in models of Parkinson's disease

Parkinson's disease (PD) is a devastating neurodegenerative disorder characterized by the loss of neurons in the substantia nigra pars compacta and the presence of Lewy bodies in surviving neurons. These intracellular protein inclusions are primarily composed of misfolded α-synuclein (aSyn), which has also been genetically linked to familial and sporadic forms of PD. DJ-1 is a small ubiquitously expressed protein implicated in several pathways associated with PD pathogenesis. Although mutations in the gene encoding DJ-1 lead to familial early-onset PD, the exact mechanisms responsible for its role in PD pathogenesis are still elusive. Previous work has found that DJ-1--which has protein chaperone-like activity--modulates aSyn aggregation. Here, we investigated possible physical interactions between aSyn and DJ-1 and any consequent functional and pathological relevance. We found that DJ-1 interacts directly with aSyn monomers and oligomers in vitro, and that this also occurs in living cells. Notably, several PD-causing mutations in DJ-1 constrain this interaction. In addition, we found that overexpression of DJ-1 reduces aSyn dimerization, whereas mutant forms of DJ-1 impair this process. Finally, we found that human DJ-1 as well as yeast orthologs of DJ-1 reversed aSyn-dependent cellular toxicity in Saccharomyces cerevisiae. Taken together, these data suggest that direct interactions between DJ-1 and aSyn constitute the basis for a neuroprotective mechanism and that familial mutations in DJ-1 may contribute to PD by disrupting these interactions.

Infecção sistêmica por Mycobacterium avium em cão: relato de caso

Infecções sistêmicas causadas pelo complexo Mycobacterium avium em cães são consideradas raras. Em cães e gatos, a infecção resulta da ingestão de carne ou do contato com solo ou fômites contaminados. As manifestações clínicas de cães infectados por M. avium tendem a ser vagas ou ausentes, logo o diagnóstico in vivo torna-se difícil. A suspeita de infecção sistêmica por micobacteriose ocorreu, neste relato, após a identificação de bacilos álcool-ácido resistentes na amostra de medula óssea, os quais foram identificados como Mycobacterium avium pelo método molecular de reação em cadeia da polimerase com análise de restrição (PCR-PRA). Este animal apresentava uma aplasia de medula óssea em decorrência de Erhlichia canis, corroborando a maioria dos relatos na literatura em que se associa essa infecção a pacientes imunossuprimidos.

AG490 promotes HIF-1α accumulation by inhibiting its hydroxylation

AG490 is a tyrphostin originally described as a Janus Activated Kinase (JAK) 2 inhibitor. AG490 also inhibits epidermal growth factor receptor (EGFR) and guanylyl cyclases (GC). More recently, AG490 was associated with oxidative stress protection in experimental acute kidney injury models. We now show that AG490 is also a strong activator of the Hypoxia Inducible Factor (HIF)-1. Under normoxic conditions HIF-1α is degraded through hydroxylation, von Hippel Lindau protein (VHL)-mediated ubiquitin tagging and proteasomal degradation. AG490 increased HIF-1α protein, but not HIF-1α mRNA levels, dose- and time-dependently in cultured endothelial, vascular smooth muscle and kidney proximal tubular epithelial cells. AG490 increased HIF-1α protein half-life, suggesting that HIF-1α protein accumulation resulted from a decreased degradation. In this regard, AG490 prevented HIF-1α hydroxylation and increased HIF-1α protein levels in human renal carcinoma cells expressing VHL, but did not further increase HIF-1α in VHL negative cells. AG490 did not prevent the proteasomal degradation of other proteins. HIF-1α was not upregulated by dominant negative JAK2constructs, tyrphostin AG9, the EGFR inhibitors erbstatin and genistein, the GC inhibitor Ly83583 or cGMP analogues. Finally, AG490 also increased HIF-1α transcriptional activity evidenced by the increased HIF-1α-dependent VEGF expression. In conclusion, AG490 is a novel HIF-1α activator that increases HIF-1α half-life and protein levels through interference with HIF-1α hydroxylation and VHL-mediated degradation. This action may contribute to the cell and tissue protective effects of AG490.

Dynamical model for competing opinions

We propose an opinion model based on agents located at the vertices of a regular lattice. Each agent has an independent opinion (among an arbitrary, but fixed, number of choices) and its own degree of conviction. The latter changes every time two agents which have different opinions interact with each other. The dynamics leads to size distributions of clusters (made up of agents which have the same opinion and are located at contiguous spatial positions) which follow a power law, as long as the range of the interaction between the agents is not too short; i.e., the system self-organizes into a critical state. Short range interactions lead to an exponential cutoff in the size distribution and to spatial correlations which cause agents which have the same opinion to be closely grouped. When the diversity of opinions is restricted to two, a nonconsensus dynamic is observed, with unequal population fractions, whereas consensus is reached if the agents are also allowed to interact with those located far from them. The individual agents' convictions, the preestablished interaction range, and the locality of the interaction between a pair of agents (their neighborhood has no effect on the interaction) are the main characteristics which distinguish our model from previous ones.

Effects of rotation on the nonlinear friction of a damped dimer sliding on a periodic substrate

Rotational effects on the nonlinear sliding friction of a damped dimer moving over a substrate are studied within a largely one-dimensional model. The model consists of two masses connected rigidly, internally damped, and sliding over a sinusoidal (substrate) potential while being free to rotate in the plane containing the masses and the direction of sliding. Numerical simulations of the dynamics performed by throwing the dimer with an initial center of mass velocity along the substrate direction show a richness of phenomena including the appearance of three separate regimes of motion. The orientation of the dimer performs tiny oscillations around values that are essentially constant in each regime. The constant orientations form an intricate pattern determined by the ratio of the dimer length to the substrate wavelength as well as by the initial orientations chosen. Corresponding evolution of the center of mass velocity consists, respectively, of regular oscillations in the first and the third regimes, but a power law decay in the second regime; the center of mass motion is effectively damped in this regime because of the coupling to the rotation. Depending on the initial orientation of the dimer, there is considerable variation in the overall behavior. For small initial angles to the vertical, an interesting formal connection can be established to earlier results known in the literature for a vibrating, rather than rotating, dimer. But for large angles, on which we focus in the present paper, quite different evolution occurs. Some of the numerical observations are explained successfully on the basis of approximate analytical arguments but others pose puzzling problems.

Detection and identification of mycobacteria in the Lisbon water distribution system

Mycobacteria have emerged as a major cause of opportunistic infections. Until the present, only a few studies have characterized mycobacteria present in the water distribution system of urban areas. In this study, we characterize these microorganisms in the Lisbon water distribution system. Our results indicate a high rate of positivities (90.5%) with mainly saprophytic mycobacteria. Around 63% of these results belong to strains of Mycobacterium gordonae indicating a generalized proliferation of this species in the Lisbon water distribution system. A total of 21.05% of the isolates are from M. kansasii, M. intracellulare and M. chelonae.

Diagnóstico das paralisias flácidas. Relato de três casos

O artigo não apresenta resumo.

Osteopatia crânio-mandibular. Relato de caso

O artigo não apresenta resumo

Lymphadenitis caused by Aerococcus urinae infection

Aerococcus urinae is rarely reported as a human pathogen. The pathogenesis of this gram-positive coccus is not fully understood. It has been identified as a cause of urinary tract infections but may be associated with severe infections such as endocarditis and septicaemia. This paper presents a case of lymphadenitis caused by A. urinae.

In vivo measurement of the brain and skull resistivities using an EIT-based method and the combined analysis of SEF/SEP data

Results of "in vivo" measurements of the skull and brain resistivities are presented for six subjects. Results are obtained using two different methods, based on spherical head models. The first method uses the principles of electrical impedance tomography (EIT) to estimate the equivalent electrical resistivities of brain (rhobrain), skull (rhoskull) and skin (rhoskin) according to. The second one estimates the same parameters through a combined analysis of the evoked somatosensory cortical response, recorded simultaneously using magnetoencephalography (MEG) and electroencephalography (EEG). The EIT results, obtained with the same relative skull thickness (0.05) for all subjects, show a wide variation of the ratio rhoskull/rhobrain among subjects (average = 72, SD = 48%). However, the rhoskull/rhobrain ratios of the individual subjects are well reproduced by combined analysis of somatosensory evoked fields (SEF) and somatosensory evoked potentials (SEP). These preliminary results suggest that the rhoskull/rhobrain variations over subjects cannot be disregarded in the EEG inverse problem (IP) when a spherical model is used. The agreement between EIT and SEF/SEP points to the fact that whatever the source of variability, the proposed EIT-based method <Au: Addition of "method" O.K? appears to have the potential to reduce systematic errors in EEG IP associated to the misspecification of rhoskull/rhobrain, rhobrain, rhoskull and rhoskin.

The effect of different psychological profiles and timings of stress exposure on humoral immune response

The aim of this study was to analyse the effects of different timings of stress exposure on humoral immune response in mice previously distinguished by their own psychological profile. The Swiss mice were submitted to two different protocols of social confrontation, based on the timing of stress exposure in relation to an immune challenge: animals socially confronted daily for 2 weeks (SINT) and another group confronted daily for 3 weeks (LINT). Control groups were individually housed in a different room. All groups were intraperitoneally injected with sheep red blood cells (SRBC). The SINT group was challenged on the 1st and 7th days of confrontation, whereas the LINT group was challenged on the 7th and 14th days. Two days prior to the period of social conflict, the animals were tested in the elevated plus-maze (PM). The SINT protocol caused a more depressed primary immune response in the submissive mice than that observed in the dominants. The LINT protocol induced a marked increase in the primary immune response, which was more evident in the dominant mice, whilst no changes were observed in the secondary immune response. In the control and dominant groups, the correlation analysis attributed a higher anti-SRBC titre to the more anxious animals; by contrast, higher anti-SRBC titres were found in the less anxious submissive mice. These studies show that different physiological and behavioural adaptations to environmental demands over time, as well as different psychological profiles, constitute important factors to a better understanding of neuro-immune interactions.

[Cognitive effects of therapy with topiramate in patients with refractory partial epilepsy]

INTRODUCTION

Multiple studies have demonstrated that antiepileptic drug therapy may have consequences on cognitive function. Topiramate (TPM) is a new antiepileptic drug characterized by several mechanisms of action, which has proved to be clinically effective in the reduction of the quantity of crisis in epileptic patients. Clinical studies frequently report subjective cognitive complains, inconsistently sustained. The main objective of this study was to assess neuropsychological effects attributable to the addition of TPM to the current antiepileptic therapy, in patients with refractory partial epilepsy.

PATIENTS AND METHODS

44 patients were assessed through a cognitive battery applied before beginning of therapy with TPM and 6 months after the dosage had been stabilized. Tests had been chosen to assess verbal and non verbal memory, executive functions, language, visuomotor processing and psychomotor functions. The cognitive study was conducted in parallel with clinical trials TOPMAT-EPAJ-111 and TOP-POR1.

RESULTS

The statistical analysis of results didn t show changes in motor tests, in sustained attention and in logical and visual memory. Deterioration of semantic verbal fluency, verbal learning, work memory and visuomotor skills was observed. Considering the effects of the dosage of topiramate and the total quantity of antiepileptic drugs, major commitment was observed in patients taking more than 400 mg/day.

CONCLUSIONS

Like other antiepileptic drugs, topiramate, used in polytherapy in patients with refractory epilepsy, may have consequences on cognitive functions. These changes may be related with the potentiating action of this drug at the level of neurotransmission system of gamma amino butyric acid (GABA), substance that has inhibitory properties in the fore regions of the brain.

The application of electrical impedance tomography to reduce systematic errors in the EEG inverse problem--a simulation study

In this paper we propose a new method, using the principles of electrical impedance tomography (EIT), to correct for the systematic errors in the inverse problem (IP) of electroencephalography (EEG) that arise from the wrong specification of the electrical conductivities of the head compartments. By injecting known currents into pairs of electrodes and measuring the resulting potential differences recorded from the other electrodes, the equivalent conductivities of brain (sigma3), skull (sigma2) and scalp (sigma1) can be estimated. Since the geometry of the head is assumed to be known, the electrical conductivities remain as the only unknown parameters to be estimated. These conductivities can then be used in the inverse problem of EEG. The simulations performed in this study, using a three-layer sphere to model the head, prove the feasibility of the method, theoretically. Even in the presence of simulated noise with a value of signal-to-noise ratio (SNR) equal to 10, estimations of the electrical conductivities within 5% of the true values were obtained. Simulations showed the existence of a strong relation between errors in the skull thickness and the EIT estimated conductivities. If the skull thickness is wrongly specified, for example overestimated by a factor of two, the conductivity determined by EIT is also overestimated by a factor of two. Simulations showed that this compensation effect also works in the inverse problem of EEG. Application of the proposed method reduces systematic errors in the dipole localization, up to an amount of 1 cm. However it proved to be ineffective to decrease the dipole strength error.

[Tumor of the carotid body (paraganglioma)]

Carotid body tumours (paragangliomas) are uncommon but rather an interesting pathology, due to the controversy that still remains regarding their histopathologic behaviour (malignancy?), as well as their diagnosis and management. Because of its nature being composed of chemoreceptor paraganglionic tissue, the carotid body responds to lower partial pressure of oxygen and can cause severe cardiovascular disturbances. Based upon a series of 12 cases, the authors reviewed this pathology in detail, and discussed the methods of diagnosis and treatment, which they considered more appropriate.

[The extra-peritoneal approach in the surgical treatment of atherosclerosis in the aorto-iliac region]

Based upon a series of 27 cases the results obtained with the extraperitoneal approach for the surgical management of atherosclerosis of the aorto-iliac segment, are presented and discussed. The patients, ranging in age from 55 to 87 years (mean 70.9 years) were considered as high risk patients because of associated respiratory, cardiac and renal diseases. The technique of extraperitoneal approach was applied in 8 cases (29.7%) of abdominal aortic aneurysms (AAA), and 19 cases (70.3%) of aorto-iliac occlusive disease (DOAI), with an operative mortality of 3.7%. It has been concluded that the extraperitoneal approach is an attractive alternative to the conventional transabdominal approach, particularly in those patients with significant risk factors, requiring aorto-iliac surgical reconstruction.

Experimental Trypanosoma cruzi cardiomyopathy in BALB/c mice. The potential role of intravascular platelet aggregation in its genesis

In male BALB/c mice aged 5-6 weeks inoculated three times at intervals of 15 days with 1 X 10(7) epimastigote forms of the PF strain of Trypanosoma cruzi and challenged 30 days after the last inoculation with 2 X 10(4) trypomastigote forms of the Colombia strain of T cruzi (the mice were sacrificed 80-100 days after the challenge) a cardiomyopathy very similar to that observed in the chronic phase of Chagas' disease in man develops. The cardiac syndrome is characterized grossly by cardiomegaly with hypertrophy, dilatation of ventricular chambers, and thinning of the apex of the left ventricle (apical aneurysm) and microscopically by focal areas of myocytolytic necrosis and myocardial degeneration with an inflammatory response composed of mononuclear cells (predominantly macrophages and a few lymphocytes) with concurrent interstitial fibrosis and occasional myofibers containing pseudocysts. In addition, aggregated platelets and occlusive thrombi were found in small epicardial and intramyocardial vessels of infected mice as compared with controls. The potential role of intravascular platelet aggregation in the causation of focal myocardial necrosis and degeneration and apical aneurysm in experimental T cruzi cardiomyopathy in BALB/c mice is discussed.