Perceived need of health care and barriers in access to health services among migrants in Portugal

 

Health care has been pointed out as a key determinant of migrants' health and social integration, but there is evidence of disparities in its access across subgroups. A deeper understanding of the barriers in access to health care, particularly among vulnerable groups, is needed. Our study aims to examine perceived need of health care, access to health services and barriers among migrants in Portugal. A cross-sectional survey was conducted with 1126 adult migrants (53.4% females), originated from African, Middle East, Asian countries and Brazil, living in Portugal for no longer than 10 years. The collected data included sociodemographic characteristics, perceived need of health care, access to health services and difficulties experienced. Differences between groups were analysed through chi-square tests. Results showed that most of the participants (64.7%) have needed health care in the previous 12 months in Portugal. Of these, 87.8% accessed a health care service. However, even needing health care, 3.3% decided not to seek care and 8.8% were not able to access a health care service. Reporting no access to health care was more frequent among migrants with shorter length of stay in the country (<1 year: 19.4% vs. 1 to 5 years: 7.3% and 6 to 10 years: 4.6%; p = 0.001) and those with non-regular migration status (in regularisation process: 11.5% and undocumented: 9.5% vs. documented: 7.2%; p = 0.040). Most common barriers were lack of the National Health Service user card (38%), financial constraints (15%), undocumented status (11%) and language difficulties (7%). Although efforts have been made over the past decades in Portugal to adopt inclusive policies and promote migrants' access to health care, strategies are needed to improve information on migrants' health rights, especially of those undocumented and recently arrived. Economic and language difficulties should be further addressed in comprehensive interventions to promote equal access to health care.

Key messages

Migrants residing in the country for less than a year and those with non-regular migration status reported more frequently not being able to access health care. Despite the efforts to adopt inclusive policies and promote migrants’ access to health care, strategies are needed to improve information on migrants’ health rights and promote equal access to care.

Relationship between air temperature and mortality in two Portuguese cities

Background

Current global climate changes are significant and the concern with temperature-related mortality have been investigated, especially related to extreme heat. In the current Portuguese scenario of health decentralization to municipalities, knowing the local climate profile associated to other risks allows public policies to be implemented to protect population.

Methods

The present study is observational and cross-sectional in two Portuguese cities, Odivelas and Torres Vedras. The daily data on average temperature and the number of deaths were analyzed between 2015 to 2018. The data were provided by statistics Portugal and Portuguese Institute of Sea and Atmosphere. For data organization and preliminary analysis, Microsoft Power BI and Phyton software were used.

Results

A scatter plot of the average day-temperature versus the number of deaths showed that the variables did not present a clear functional form, but there is symmetry on the graph. Preliminary analyzes were performed between these variables which resulted in a Pearsońs coefficient of -0.17 (p-value = 0.000, confidential interval = 95%) for Torres Vedras and -0.21 (p-value = 0.000, confidential interval = 95%) for Odivelas. The negative coefficient means the lower the temperature, greater the number of deaths. However, these results show that the coefficient is weak and there is no correlation with each other.

Conclusions

The result shows that the average day-temperature and the number of deaths is not correlated and it will be necessary to include other variables in the study. Other data will be assessed, including period and related factors (season and seasonality, for example). The statistical evaluation for the maximum and minimum temperature data for the day will be applied. Gender and age will be available too. In addition, mortality, morbidity, medication consumption and other environmental variables will also be analyzed.

Key messages

We believe that the results of this study will provide data for the development of public health policies. The decentralization of health to cities is a challenge that needs data support.

Solid base catalytic hydrothermal liquefaction of macroalgae: Effects of process parameter on product yield and characterization

The hydrothermal liquefaction (HTL) of Sargassum tenerrimum (ST) macroalgae was carried out for 15 min, over various solid base catalysts (CaO supported on CeO₂, Al₂O₃, and ZrO₂) at different reaction temperatures (260-300 °C), different catalyst quantities (5-25 wt%) and using different solvent systems. Maximum bio-oil (BO) yields for the non-catalytic HTL with single solvent water, ethanol, and water-ethanol co-solvent were 3.3 wt%, 23.3 wt%, and 32.0 wt%, respectively, at 280 °C. Ethanol as single solvent elicited highest BO yield of 25.2 wt% with CaO/ZrO₂ (10.0 wt%) catalyst. However, the highest BO yield (33.0 wt%) accompanied by higher conversion (70.5%) was obtained with CaO/ZrO₂ (10.0 wt%) under water-ethanol co-solvent. The selectively higher percentage of ester functional compounds (87.8%) was found with CaO/ZrO₂ catalyst under water-ethanol co-solvent. Also, the bio-oil obtained from catalytic liquefaction showed a higher high heating value (HHV) compared to that from the non-catalytic HTL reaction.

Public health policy implementation and evaluation in portugal and israel (Project PH.PIE): the intersectoral pledge and the case of health literacy for tobacco control in the building of the Homo Salus

Despite the overwhelming accumulated evidence of the negative effects of nicotine intake, the prevalence of tobacco use is not expected to decline in the near future in several countries. Israel and Portugal both signed the WHO Framework Convention on Tobacco Control (WHO FCTC) and implemented several strategies to achieve Positive Public Health Outcomes (PPHO) (e.g. policy making, legislation). Nevertheless during the past 10 years the number of smokers in Israel has decreased from 28% (in 2000) to about 20.6% (in 2017), while in Portugal, the number of smokers has not changed (2002, 19.2%). However, it has increased for women and adolescents.

The goal of PH.PIE project (Public Health Policy Implementation & Evaluation) is to document policy development and implement Health Impact Assessment (HIA) towards a knowledgeable civic society, searching for the real PPHO. Tobacco control is a selective topic because of its high relevance in public health. PH.PIE considers policy making and stakeholder analysis to comprehend HIA of strategic public health issues and PPHO.

The tobacco industry during the last 10 years has invaded the market with a comprehensive new approach, built around the concept of harm reduction and turnaround strategies to counteract WHO FCTC principles. This way, public health has apparently lost its grip from its own argumentative discourse, while several stakeholders have positioned themselves in the co-working facelift of nicotine use with smokeless tobacco, electronic cigarettes, and other forms of use that have not been scrutinized in terms of their real potential on public health terms.

Harm reduction approaches take the front line, in contrast to smoking cessation efforts as a cornerstone of WHO FCTC. We argue in this paper that health literacy can be critical tool in re-making nicotine addiction in the homo salus upbringing.

APPLICATION OF DROPLET DETECTORS TO ALPHA RADIATION DETECTION

Superheated droplet detectors (SDDs) are traditionally employed in the detection of neutrons. In this work the focus is on the detection of alpha particles using C2ClF5 as the target liquid. The alpha-droplet interaction is examined via computational studies, and a geometric model developed to describe the expected detector response. Experiments with alpha-emitting uranium- and samarium-doped SDDs at temperatures of 5-12°C confirm that the event rate is related to the size of the droplets, and are in model agreement for temperatures below 8°C; above this temperature, the acoustic sensitivity is reduced by signal attenuation as a result of the increasing bubble population, for which the addition of an attenuation coefficient restores the agreement with experiment. The results suggest the viability of a SDD-based alpha spectrometer using mono-sized droplets.

Nutritional quality of packaged foods targeted at children in Brazil: which ones should be eligible to bear nutrient claims?

OBJECTIVES

This study aimed to assess the nutritional quality of food products marketed at children, with and without nutrient claims, using two different approaches.

METHODS

Analyses were performed based on a data set with food composition and labelling data from every packaged food marketed at children sold in a major Brazilian supermarket (n=535). Foods were classified as 'healthier' and 'less healthy' according to the UK/Ofcom nutrient profile model and to the NOVA classification based on the level of food processing. Pearson's χ² test was used to compare proportions between models. Agreement was assessed using Cohen's κ-statistic (P<0.05).

RESULTS

The NOVA model was stricter than the UK/Ofcom model, classifying more products as 'less healthy' (91.4%) compared with the nutrient profile-based model (75.0%; P<0.001). Agreement between models was 79.4% (k=0.30), because 72.9% (n=390) of products were categorised as 'less healthy' by both models, and 6.5% (n=35) as 'healthier'. Half of the food products marketed at children from the database (270; 50.5%) bore nutrient claims. From these products with nutrient claims, 95.9% (92.8-98.0) were classified as 'less healthy' by the NOVA model, whereas this percentage was 74.1% (68.4-79.2) according to the UK/Ofcom model (P<0.05).

CONCLUSIONS

The high number of foods with low nutritional quality being marketed at children via product packaging and nutrient claims should be of concern to policy makers wanting to improve children's diets and to tackle childhood obesity. The implementation of nutritional quality criteria to ensure that foods targeted at children should be eligible to bear nutrient claims on their labels could avoid a situation where claims mask the overall nutritional status of a food.

Characterisation of the epithermal neutron irradiation facility at the Portuguese research reactor using MCNP

The radiation field at the epithermal beamline and irradiation chamber installed at the Portuguese Research Reactor (RPI) at the Campus Tecnológico e Nuclear of Instituto Superior Técnico was characterised in the context of Prompt Gamma Neutron Activation Analysis (PGNAA) applications. Radiographic films, activation foils and thermoluminescence dosimeters were used to measure the neutron fluence and photon dose rates in the irradiation chamber. A fixed-source MCNPX model of the beamline and chamber was developed and compared to measurements in the first step towards planning a new irradiation chamber. The high photon background from the reactor results in the saturation of the detector and the current facility configuration yields an intrinsic insensitivity to various elements of interest for PGNAA. These will be addressed in future developments.

Final analysis and results of the Phase II SIMPLE dark matter search

We report the final results of the Phase II SIMPLE measurements, comprising two run stages of 15 superheated droplet detectors each, with the second stage including an improved neutron shielding. The analyses include a refined signal analysis, and revised nucleation efficiency based on a reanalysis of previously reported monochromatic neutron irradiations. The combined results yield a contour minimum of σp=5.7×10(-3)  pb at 35  GeV/c2 in the spin-dependent sector of weakly interacting massive particle (WIMP) proton interactions, the most restrictive to date for MW}≤60  GeV/c2 from a direct search experiment and overlapping, for the first time, with results previously obtained only indirectly. In the spin-independent sector, a minimum of 4.7×10(-6)  pb at 35  GeV/c2 is achieved, with the exclusion contour challenging a significant part of the light mass WIMP region of current interest.

First results of the Phase II SIMPLE dark matter search

We report results of a 14.1   kg d measurement with 15 superheated droplet detectors of total active mass 0.208 kg, comprising the first stage of a 30 kg d Phase II experiment. In combination with the results of the neutron-spin sensitive XENON10 experiment, these results yield a limit of |a(p)|<0.32 for M(W)=50 GeV/c² on the spin-dependent sector of weakly interacting massive particle-nucleus interactions with a 50% reduction in the previously allowed region of the phase space, formerly defined by XENON, KIMS, and PICASSO. In the spin-independent sector, a limit of 2.3×10⁻⁵ pb at M(W)=45 GeV/c² is obtained.

An enhancer/promoter combination strengthens the expression of blood-coagulation factor VIII in non-viral expression vectors

We explored the potential of fusion of hepatic locus control region 1 (HCR-1) with HCR-2 to express B-domain-deleted human factor VIII (FVIII) in four cell lines. B-domain-deleted human FVIII expression was controlled by HCR-1/HCR-2, followed by liver specific and ubiquitous promoters. Chimera enhancer HCR-1/HCR-2, followed by cytomegalovirus (CMV) promoter, gave 2-fold more FVIII expression in all cell lines (105.6 +/- 2.8 for Hek-293, 68.8 +/- 3.8 for HepG2, 34.8 +/- 1.3 for CHO, and 27.2 +/- 1.6 ng x mL(-1) x 10(6) cells(-1) for L.N.) when compared to the vector with CMV alone (54.8 +/- 3.3 for Hek-293, 32.4 +/- 1.2 for HepG2, 18.6 +/- 1.1 for CHO, and 10.1 +/- 1.7 ng x mL(-1) x 10(6) cells(-1) for L.N.). Elongation factor 1-alpha gene and human CMV promoters were more efficient than the promoters from the human alpha-1-antitrypsin gene, and fviii was less efficient in hepatic cell lines. HCR-1/HCR-2, followed by strong promoters, increases FVIII expression in vitro. Our results underscore the importance of cis sequences for enhancing in vitro FVIII expression; this may be helpful for designing new strategies to improve heterologous expression systems.

Phase behaviour of stearic acid–stearonitrile mixtures

The solid-liquid phase behaviour of stearic acid (SA) and stearonitrile (SN) in binary mixtures was investigated by differential scanning calorimetry (DSC), and the formation of SA-SN mixed monolayers at the air-water interface was followed by surface pressure-area (pi-A) measurements and by Brewster angle microscope (BAM) observation. The solid-liquid phase diagram is a eutectic type phase diagram, with the eutectic composition 0.90<X(SN)<0.95 and T(eut)=40.9 degrees C. The DSC results also suggest that the two components are immiscible in the solid phase but form a liquid mixture with positive deviations to the ideal behaviour. At the air-water interface, the two components form liquid condensed monolayers in the entire range of compositions, at low surface pressures, while solid mixed monolayers only form at high surface pressures for X(SN)<0.8. Thermodynamic analysis indicates that SA and SN are miscible in the liquid condensed phase, with negative deviations from the ideal behaviour. The variation of the collapse surface pressure of mixed monolayers also indicates miscibility at the air-water interface.

Dosimetry at the Portuguese research reactor using thermoluminescence measurements and Monte Carlo calculations

This work presents an extensive study on Monte Carlo radiation transport simulation and thermoluminescent (TL) dosimetry for characterising mixed radiation fields (neutrons and photons) occurring in nuclear reactors. The feasibility of these methods is investigated for radiation fields at various locations of the Portuguese Research Reactor (RPI). The performance of the approaches developed in this work is compared with dosimetric techniques already existing at RPI. The Monte Carlo MCNP-4C code was used for a detailed modelling of the reactor core, the fast neutron beam and the thermal column of RPI. Simulations using these models allow to reproduce the energy and spatial distributions of the neutron field very well (agreement better than 80%). In the case of the photon field, the agreement improves with decreasing intensity of the component related to fission and activation products. (7)LiF:Mg,Ti, (7)LiF:Mg,Cu,P and Al(2)O(3):Mg,Y TL detectors (TLDs) with low neutron sensitivity are able to determine photon dose and dose profiles with high spatial resolution. On the other hand, (nat)LiF:Mg,Ti TLDs with increased neutron sensitivity show a remarkable loss of sensitivity and a high supralinearity in high-intensity fields hampering their application at nuclear reactors.

The simple SDD

We describe the fabrication and characterisation of the SIMPLE superheated droplet detector, a 10 g active mass device of C(2)ClF(5) in 1-3% weight concentrations currently employed in a direct search for spin-dependent astroparticle dark matter candidates.

Photon and fast neutron dosimetry using aluminium oxide thermoluminescence dosemeters

Al(2)O(3):Mg,Y thermoluminescence (TL) dosemeters were used to measure photon and fast neutron doses in a fast neutron beam recently implemented at the Portuguese Research Reactor, Nuclear and Technological Institute, Portugal. The activation of Al(2)O(3):Mg,Y by fast neutrons provides information about the fast neutron component by measuring the activity of the reaction products and the self-induced TL signal. Additionally, the first TL reading after irradiation determines the photon dose. The elemental composition of the dosemeters was determined by instrumental neutron activation analysis and by particle induced X-ray emission. Results demonstrate that Al(2)O(3):Mg,Y is an adequate material to discriminate photon and fast neutron fields for reactor dosimetry purposes.

Neutron spectrometry with large volume, heavy-loaded superheated droplet detectors: a simple spin-off

SIMPLE is a superheated droplet detector (SDD) experiment designed to search for the evidence of spin-dependent weakly interacting neutralino dark matter (WIMPs). SDDs, a type of emulsion detector, consist of a uniform suspension of superheated liquid droplets in a compliant material such as a polymeric or aqueous gel. We report on the first neutron spectrometry experiments with SIMPLE SDDs, a spin-off of the neutron detector calibrations performed at the Portuguese Research Reactor. SIMPLE SDDs differ from most SDDs available commercially as they have a 10 times higher loading factor, containing 10(3) times more freon than their commercial counterparts and a 100 times larger volume. We have analysed the response of SIMPLE SDDs to two quasi-monochromatic neutron beams of energies 54 and 144 keV obtained with passive filters. Results show that the characteristic peaks in the fluence distribution of both filters could be determined and their energy position obtained using a simple thermodynamic relation.

Development of equipments for determination of BNCT source spectral parameters

The knowledge of neutron and gamma ray energy spectra can strongly influence the BNCT information about delivered dose to target volume as well as to the surface healthy tissue region. This region is very often decisive to stay within the recommended healthy tissue limit. Modification of neutron Bonner spectrometer to one block i.e. Bonner spectrometer monoblock (BSM) and gamma ray Si semiconductor spectrometer are being developed and verified in real conditions of LVR-15 reactor beam. Test measurements were also carried out in conditions of known standard spectra. The accepted procedure and the first results documenting the sensitivity BSM to different spectra are presented.

Thermoluminescence dosimetry of a thermal neutron field and comparison with Monte Carlo calculations

The characteristics of thermoluminescence dosemeters (TLDs) regarding the determination of photon and neutron absorbed doses were investigated in a thermal neutron beam. Harshaw TLD-100 (LiF:Mg,Ti) and TLD-700 (7LiF:Mg,Ti) were compared with similar materials from Solid Dosimetric Detector and Method Laboratory (People's Republic of China). Harshaw TLD-700H (7LiF:Mg,Cu,P) and aluminium oxide (Al2O3:Mg,Y) from Hungary were also considered for photon dose measurement. The neutron sensitivity of the investigated materials was measured and found to be consistent with values reported by other authors. A comparison was made between the TL dose measurements and results obtained via conventional methods. An agreement within 20% was obtained, which demonstrates the ability of TLD for measuring neutron and photon doses in a mixed field, using careful calibration procedures and determining the neutron sensitivity for the usage conditions.

Mineralisation of two phosphate ceramics in HBSS: role of albumin

The role of albumin in the mineralisation process of commercial hydroxyapatite (HAp) and synthesised biphasic (HAp-tricalcium phosphate) ceramics in a bufferless simulated inorganic plasma (HBSS) was investigated by conventional in vitro tests and static and dynamic wettability measurements. Albumin was either pre-adsorbed or solubilised in HBSS. It was found that calcium complexation by albumin plays a key role in early mineralisation kinetics, so that mineralisation is favoured when albumin is pre-adsorbed and hindered when it is dissolved in HBSS. In the biphasic ceramic this picture is complicated by the fact that albumin, in solution, seems to promote the dissolution of tricalcium phosphate, and simultaneously compete for calcium with the ceramic. It also appears that albumin has a stabilising effect of octacalcium phosphate present in deposits on commercial HAp. The same effect may be present in the case of the biphasic ceramic, at earlier mineralisation times, when octacalcium phosphate appears as a precursor of HAp. Octacalcium phosphate formation on commercial apatite is accompanied by carbonate substitution in phosphate positions.

In vitro mineralization of a glass-ceramic of the MgO-3CaO x P2O5-SiO2 system: wettability studies

The calcium phosphate deposition on the surface of a bioactive glass-ceramic of the MgO-3CaO. P(2)O(5)-SiO(2) system during a 1-week immersion in biological model fluids, was investigated through wettability studies. Two model fluids with chemical composition similar to the human blood plasma were tested: Hanks' balanced salt solution (HBSS) and a simulated body fluid (SBF) with a higher calcium content. The effect of the presence of albumin, both in solution or previously adsorbed to the surface, was assessed. The behavior observed using two SBF solutions prepared with and without TRIS buffer was compared. The surface free energy of the glass-ceramic samples was determined, before and after immersion, and dynamic contact angle analysis was performed using the biological model fluids as scanning liquids. Scanning electron microscope observations and x-ray photoelectron spectroscopy (XPS) analysis were performed to complement the wettability studies. The experimental results led to the conclusion that the precipitation of a calcium phosphate film in HBSS occurred mainly when the immersion solution was renewed daily or in the presence of adsorbed albumin. In SBF, the addition of TRIS buffer seemed to inhibit the formation of the calcium phosphate film.

Reproducibility of TL measurements in a mixed field of thermal neutrons and photons

The reproducibility of measurements performed with GR-100 (LiF:Mg,Ti) from the Solid Dosimetric Detector and Method Laboratory (DML) China, GR-107 (7LiF:Mg,Ti, DML), TLD-700H (7LiF:Mg.Cu,P, Harshaw) and Al2O3:Mg,Y (Hungary) in photon and mixed photon-neutron fields was investigated. Mixed-field irradiations were performed in a thermal neutron field generated at a nuclear reactor. GR-100 sensitivity decreased after mixed-field irradiations, while no significant change was found for the other materials. Using GR-100 for the dosimetry of mixed and high-intensity fields requires careful procedures.

Brain metastases of a malignant fibrous histiocytoma presenting as an acute cerebral hemorrhage

Intracranial metastases from malignant fibrous histiocytoma (MFH) are rare, particularly with associated hemorrhage. This article reports one case and presents a review of the literature on this topic. A 55-year-old man presented with acute drowsiness, aphasia and right homonymous hemianopsia and hemiparesis. The first CT scan showed a left occipitoparietal hematoma and the second one, nodular, contrast-enhanced lesions. He had been previously operated on soft tissues MFH. Lung metastases developed subsequently. A craniotomy was performed with evacuation of the hematoma and total gross resection of the mass lesions. Microscopic examination disclosed a metastasis from a MFH. Neoangiogenesis, stimulated by angiogenic growth factors, seems to take part in this vascular, stroke-like event. Due to longer survivals of patients harboring systemic sarcomas, these tumors should be considered in the differential diagnosis of intracranial neoplasms, whether hemorrhagic or not. In particular, history of a previous soft tissue or heart tumor associated with lung metastasis should evoke the possibility of MFH metastasis.

Calcium phosphate deposition on titanium surfaces in the presence of fibronectin

Titanium implants are known to nucleate spontaneously a calcium phosphate (apatite-like) layer when in contact with biological model fluids. The presence of proteins either in solution or pre-adsorbed on the titanium surface may influence the process of calcium phosphate deposition. The role of fibronectin, a protein known to promote cell adhesion in spite of its low concentration in biological fluids, was dissolved in Hanks' balanced salt solution (HBSS) and investigated. Several techniques of surface analysis, namely wettability, XPS, and SEM studies, were applied. The concentration of fibronectin in the HBSS solution was an important parameter in the process of calcium phosphate deposition. Concentrations as low as 0.01 mg/mL did not significantly affect the ionic precipitation; however, if the protein concentration was increased to 0.05 mg/mL, a value still far below the concentration in blood (0.2 mg/mL), the formation of a calcium phosphate layer was strongly inhibited. The influence of fibronectin pre-adsorbed on titanium surface also was investigated. It was found, as in the first case, that the extent of ionic precipitation that occurred during the immersion in HBSS depended on the protein concentration in the NaCl solution used to pre-immerse the titanium sample.

Bovine serum albumin adsorption on titania surfaces and its relation to wettability aspects

The adsorption of bovine serum albumin (BSA) from sodium chloride solution and Hanks' balanced salt solution (HBSS) onto TiO2-silicon surfaces is studied by reflectometry in stagnation point flow. The results are compared with those obtained by dynamic contact-angle (DCA) analysis of titanium substrates. The adsorption isotherms show that the adsorbed amount of protein always is lower in HBSS, that is, in the presence of calcium and phosphate ions. This may be related to the increase in surface hydrophilicity caused by these ions, as suggested by the authors in previous works. The rate of adsorption also is lower in HBSS solutions. Comparison of the initial adsorption rates with the rate of mass transfer to the surface reveals that in both solvents only a small fraction of the protein that arrives at the surface adsorbs onto it. Electrostatic and/or conformational effects can explain the energy barrier to adsorption. The DCA analysis of high concentration (4 mg/mL) protein solutions shows a strong reduction of the contact-angle hysteresis, both in HBSS and in NaCl solutions, which confirms that the immediate adsorption of the protein to the surface forms a stable, hydrophilic film.

Estimation of the Surface Properties of Styrene-Acrylonitrile Random Copolymers from Contact Angle Measurements

The surface free energy per unit area of a solid, gamma(S), is a fundamental property of materials and determines their surface and interfacial behavior in processes like wetting and adhesion. In this study the gamma(S) of a series of styrene-acrylonitrile random copolymers is evaluated. Three different approaches are used to determine the components in which the surface free energy can be decomposed. Using the geometric and the harmonic mean approach, the dispersive, gamma(d), and polar, gamma(p), components of the solid surface free energy were determined and compared to the Lifshitz-van der Waals, gamma(LW), and acid-base, gamma(AB), components using the approach developed by C. J. van Oss et al. (1987, Adv. Colloid Interface Sci. 28, 35). The acid-base approach was also used to evaluate the work of adhesion of the test liquids: water, glycerol, and thiodiglycol. It was found that the contact angles of these liquids follow closely the predictions of Cassie equation. The evaluation of the surface free energy components on one hand and the relative magnitude of the work of adhesion components on the other hand, suggest that below 50% of acrylonitrile the polystyrene repeating units are preferentially at the surface. Above 50% of acrylonitrile the segregation of the low-energy homopolymer at the surface decreases. Copyright 1999 Academic Press.

Homologous xylanases from Clostridium thermocellum: evidence for bi-functional activity, synergism between xylanase catalytic modules and the presence of xylan-binding domains in enzyme complexes

Clostridium thermocellum produces a consortium of plant-cell-wall hydrolases that form a cell-bound multi-enzyme complex called the cellulosome. In the present study two similar xylanase genes, xynU and xynV, were cloned from C. thermocellum strain YS and sequenced. The deduced primary structures of both xylanases, xylanase U (XylU) and xylanase V (XylV), were homologous with the previously characterized xylanases from C. thermocellum strain F1. Truncated derivatives of XylV were produced and their biochemical properties were characterized. The xylanases were shown to be remarkably thermostable and resistant to proteolytic inactivation. The catalytic domains hydrolysed xylan by a typical endo-mode of action. The type VI cellulose-binding domain (CBD) homologue of XylV bound xylan and, to a smaller extent, Avicel and acid-swollen cellulose. Deletion of the CBD from XylV abolished the capacity of the enzymes to bind polysaccharides. The polysaccharide-binding domain was shown to have a key role in the hydrolysis of insoluble substrates by XylV. The C-terminal domain of XylV, which is absent from XylU, removed acetyl groups from acetylated xylan and acted in synergy with the glycosyl hydrolase catalytic domain of the enzyme to elicit the hydrolysis of acetylated xylan.

Crystallization and preliminary X-ray diffraction analysis of a myotoxic phospholipase A(2) homologue from Bothrops neuwiedi pauloensis venom

Crystals of a myotoxic phospholipase A(2) from Bothrops neuwiedi pauloensis have been obtained. They diffracted at 2.5 A resolution using a synchrotron radiation source and belong to space group P3(1)21. Preliminary analysis shows that there are two molecules in the asymmetric unit.

[Antioxidant effect of drugs used in cardiovascular therapy]

Oxidative stress is implicated in the pathogenesis of various cardiovascular disorders. The knowledge, characterisation and comparison of the different antioxidant properties of some cardiovascular drugs might lead to new therapeutic approaches. Blood constituents are biological products easier to obtain. Their oxidative damage is accepted to be involved in several pathogenic pathways such as atherogenesis. Blood products can be utilised as in vitro models of macromolecular and cellular oxidative damage. It is well known that transition metals catalyse the generation of more damaging reactive oxygen species. We studied the antioxidant effect of four beta-adrenergic blocking agents (pindolol, propranolol, atenolol and metoprolol) and of one calcium channel antagonist (nifedipine), on the plasma oxidative damage induced by copper. Lipid peroxidation was evaluated by measuring fluorescent substances. We added the drugs to the assay system, before and after the induction of peroxidation by copper, to elucidate their ability to prevent and/or block lipid peroxidation. We observed that pindolol, propranolol and nifedipine have antioxidant properties, in the assay system, when added 15 min before the addition of copper. This effect is demonstrated by the delay in initiation and decrease in formation of lipid peroxidation products. Nifedipine also has a remarkable chain breaking effect. We compared the drugs with ascorbic acid in their relative antioxidant effect: nifedipine > ascorbate > pindolol > propranolol.

[Effect of silibinin on oxidative damage of blood constituents]

Silibinin (SDH) is a flavonoid with ascertained hepatoprotective effects, which have been partially attributed to its antioxidant properties. Oxidation of blood constituents could have a role in atherogenesis and interfere with the rheologic properties of the blood. In this study we investigated, whether SDH could protect some blood constituents against oxidative modification. In human plasma we measured TBARS and fluorescence generation as indicators of copper or azobis amidinopropane hydrochloride (AAPH) at 760 mm Hg PO2-induced lipid peroxidation. SDH at 50 microM inhibited copper-induced TBARS formation by 25% and fluorescence by 47%. SDH also inhibited AAPH-induced lipid peroxidation, but at 175 microM concentration only. Oxidative modification of albumine was evaluated by fluorescence generation. SDH at 50 microM inhibited copper/hydrogen peroxide fluorescence generation by 54% and at 2.5 microM it inhibited EDTA-Fe (II)/hydrogen peroxide fluorescence generation by 31%. The protection of albumin by SDH was confirmed by SDS-PAGE electrophoresis. Copper-induced red-cell lipid peroxidation was evaluated by TBARS formation. SDH at 250 microM inhibited copper-induced lipid peroxidation and hemolysis by 45% and 94%, respectively. SDH also inhibited hemolysis in red-cell suspensions exposed to hydrogen peroxide, but not lipid peroxidation. Our results show that SDH may protect blood constituents from oxidative damage.

Apatite deposition on titanium surfaces--the role of albumin adsorption

Titanium implant surfaces are known to spontaneously nucleate apatite layers when in contact with simulated body fluids. However, adsorption of proteins may influence the process of apatite layer formation. In this study the role of bovine serum albumin (BSA) adsorption in the process of apatite deposition on titanium substrates is investigated. Deposition of calcium phosphate was induced by immersing titanium substrates in a Hank's balanced salt solution (HBSS) for times ranging from 1 to 23 days. The resulting substrates were studied by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), wettability measurements and electrochemical impedance determinations. All these methods indicate the presence of a calcium phosphate layer. The same procedure was repeated substituting HBSS with a solution of BSA in HBSS. Although SEM, EDS and electrochemical impedance spectra do not reveal the presence of an apatite layer, XPS analysis strongly indicates that the inhibition of apatite formation by BSA is only partial. The competition between BSA adsorption and apatite deposition seems to lead to a mixed film where the protein co-exists with calcium phosphate. Wettability studies suggest that this surface film is heterogeneous and porous, similar to the thicker films formed in albumin-free HBSS.

Different effects of thiol and nonthiol ace inhibitors on copper-induced lipid and protein oxidative modification

Differences among angiotensin-converting enzyme inhibitors (ACEI) in scavenging reactive oxygen species were described and mainly attributed to the presence or absence of a thiol group. Plasma constituents and red cells are known targets for oxidative damage. Transition metals, like copper, are well known catalizers of free radical generation. In the present study we compared the abilities of captopril (a thiol ACEI), enalaprilat, and lisinopril (two nonthiol ACEI) for inhibiting copper-induced thiobarbituric acid reactive substances (TBARS) formation and fluorescence generation in whole human plasma and low-density lipoprotein. The effects of those ACEI on copper/hydrogen peroxide-induced fluorescence development and electrophoretic mobility modification in albumin and on copper-induced TBARS formation and hemolysis in human red cells were also compared. Captopril was more effective than the two nonthiol ACEI in inhibiting plasma and LDL lipid peroxidation, but it was ineffective in inhibiting the albumin oxidative modification that was moderately inhibited by enalaprilat and lisinopril. On the contrary, the inhibitory effects of the three ACEI on copper-induced lipid peroxidation and hemolysis in red cell suspensions were more uniform. This as yet unreported red cell protective effect may deserve pharmacological evaluation. Our results show that captopril is a more effective antioxidant than the nonthiol ACEI in some systems. However, the nonthiol ACEI also have the ability to partially protect some targets against oxidative damage. These observations suggest that the presence of a thiol group in the ACEI structure is not the only determinant for the antioxidant properties.

Effects of zinc on copper-induced and spontaneous lipid peroxidation

Zinc (Zn) is an essential nonredox metal that has been regarded as having antioxidant properties. Some epidemiological indications and therapeutic results point to a role of Zn in restricting the development and the progression of some diseases. Redox-active metals like iron and copper are involved in oxidative injury mechanisms, and a decrease in the Zn:Cu ratio may be associated with certain pathologies. We studied the effect of Zn on the copper-induced lipid peroxidation in diluted human plasma. Lipid peroxidation was evaluated by measuring the formation of conjugated dienes and of thiobarbituric acid reactive products. We found that 20 microM Zn reduced the 125-microM copper-dependent formation of conjugated dienes by 27% and of thiobarbituric acid reactive products by 49%, during a 3-h incubation period. The inhibition of lipid peroxidation by 125 microM Zn is almost total in the same conditions. The time-course study of the inhibitory effect of 125 microM Zn showed that it lasted for 7 h, which was the maximum incubation period tested. We also found that Zn had an inhibitory effect on the spontaneous lipid peroxidation in rat brain whole homogenates. Our results support the antioxidant properties of Zn, which may be potentially relevant to the protection of human plasma constituents, competing with the transition metals for redox reactions.

[Stress proteins]

Cells from all organisms have developed a remarkable number of strategies to deal with adverse changes in their environment. One of these protective mechanisms is the heat shock response, or stress response, characterized by the extremely rapid increased expression of a selected group of proteins--the heat shock proteins (hsp)--after a sudden increase in the normal cellular growth temperature. The same response takes place when cells are subjected to a wide variety of other stressors: a) environmental assaults: exposure to heavy metals, alcohols, inhibitors of energy metabolism, amino acid analogues; b) states of disease: ischemia, oxidative injury, infectious diseases, immunity disorders and malignancy. On the other hand, some hsp are believed to play an important role in protein maturation steps and in cellular development and differentiation. The understanding of stress response is still incomplete but the promise of its medical applications for fighting against ischemia, infection, immunity diseases and cancer is clearly on the horizon.

[Ketanserin as antioxidant]

Free radicals have been related to the pathogenesis of some cardiovascular diseases. Several drugs used to treat these diseases were shown to have antioxidant properties. Our purpose was to evaluate if ketanserin, a selective S2 receptor antagonist with proven antihypertensive efficacy and which beneficially affects hemorheology, also is able to inhibit lipid peroxidation. Lipid peroxidation was induced in different biological systems in vitro and evaluated by the formation of thiobarbituric acid-reactive products. Ketanserin 50 microM inhibited copper-dependent lipid peroxidation in human red-cell suspensions by 40.8% and the subsequent hemolysis by 57,3%. It was less efficient in inhibiting hydrogen peroxide-dependent lipid peroxidation and hemolysis in the same system. Ketanserin 100 microM inhibited lipid peroxidation induced by a mixture of copper(II) and hydrogen peroxide in hepatic microsomal suspensions and in brain total homogenates by 86.2% and 56.7%, respectively. These results proved an antioxidant effect for ketanserin which was unknown, although its therapeutic relevance remains undetermined.

Hypothalamic tumor associated with atypical forms of anorexia nervosa and diencephalic syndrome

We report the case of a 10-year-old girl with a mature teratoma in the hypothalamic region. The patient presented a 2-month history of anorexia, psychic disturbances and a 37% loss of body weight. These symptoms had led initially to a diagnosis of major depression and atypical anorexia nervosa. She also presented some signs and symptoms of diencephalic syndrome. This case illustrates the importance of considering a slow-growing mass as a rare but real possibility in the differential diagnosis of anorexia nervosa, mainly in atypical cases.

Protective effects of a 21-aminosteroid against copper-induced erythrocyte and plasma lipid peroxidation

The 21-aminosteroids, or lazaroids, are a novel class of antioxidant drugs designed to inhibit iron-dependent lipid peroxidation in biological lipid environments. They have been shown to be of therapeutic value in several animal models of traumatic, ischemic and hemorrhagic injury of the central nervous system. Our purpose was to evaluate the ability of 21-aminosteroids to protect human erythrocytes and plasma against oxidative damage in vitro. We found that the 21-aminosteroid U74500A inhibited erythrocyte and plasma lipid peroxidation. U74500A at 1 microM significantly reduced copper-induced and hydrogen peroxide-induced erythrocyte lipid peroxidation by 76.5 and 27.6%, respectively. The inhibition of erythrocyte lipid peroxidation was accompanied by an inhibition of hemolysis. Copper-induced plasma lipid peroxidation was also significantly reduced by as little as 1 microM U74500A. These results suggest that 21-aminosteroids may prove useful in preventive or therapeutic interventions in situations where erythrocyte or plasma components are subjected to oxidative stress and in situations related to copper-induced oxidative damage.

[Diffuse tracheo-bronchial amyloidosis]

The case of a 52 year old man, whose initial clinical manifestations were dyspnea, bloodstained sputum and malaise is reported. After the initial cancer hypothesis, a diagnosis of diffuse primary tracheo-bronchial amyloidosis was made. The amyloid substance present was not of A A type and the plasma cells next to the deposits were polyclonal. The piece-meal removal of the masses by bronchoscopy led to profuse bleeding. The patient died with sepsis. The clinical, pathological and therapeutical aspects of lower respiratory tract amyloidosis are reviewed.

The inhibition of lipid peroxidation by cinnarizine. Possible implications to its therapeutic and side-effects

Cinnarizine has antivasoconstrictor properties and improves red-cell deformability. Its major side-effects are the induction of extrapyramidal reactions. It is a calcium antagonist, but it was suggested that its effects may depend on other mechanisms, namely on antiperoxidant properties. We have studied these properties in different biological systems, intact red-cells included. The occurrence of lipid peroxidation was determined by the formation of 2-thiobarbituric acid reactive products. Cinnarizine was found to inhibit spontaneous lipid peroxidation in rat liver homogenates, copper-induced lipid peroxidation in human plasma and copper-induced and hydrogen peroxide-induced lipid peroxidation in human red-cells. In red-cells, the inhibition of lipid peroxidation is accompanied by the inhibition of hemolysis. Copper-induced red-cell lipid peroxidation is 85% inhibited by as little as 5 microM cinnarizine. The antioxidant activity of cinnarizine may contribute to explain some of the effects of this drug.

Copper-manganese interactions concerning red-cell and plasma lipid peroxidation

Manganese decreases the formation of methemoglobin and partially inhibits lipid peroxidation induced by copper in human erythrocytes. This is followed by delay in hemolysis. Manganese also reduces lipid peroxidation induced by copper in human plasma, these effects of manganese are stronger than those of zinc, a metal which is considered to have protective effects against free radical damage.

An objective filter-based, enzymatic method for the in vivo measurement of the migration of human polymorphonuclear leucocytes

Incorporation of control valves into a previously described device enabled us to regulate the formation of 8 suction blisters on the upper surface of the forearm in adult human volunteers. After the removal of the raised epidermis and blister fluid, uniform areas of denuded dermis were obtained by placing hollow adhesive ring reinforcers onto each of the regions of exposed dermis. Single or double nitrocellulose filters were then placed onto each of the areas of moistened, exposed dermis. The chemotactic tripeptide FMLP was incorporated into 1% agarose containing 0.1% bovine serum albumin (BSA) to give a concentration range of 10(-8) M to 10(-6) M FMLP. In control systems the FMLP was omitted. Cylindrical agarose blocks +/- FMLP were then placed onto the filters and encased in individual perspex cups glued firmly onto the skin. The filter(s) and agarose blocks were replaced at 2 h intervals and polymorphonuclear leucocyte (PMNL) migration onto (single filter) and into (double filter) the filters was measured by microscopic enumeration or according to the amount of myeloperoxidase (MPO) and lysozyme in the supernatants of filters immersed in 0.1% Triton-X for 10 min to lyse the PMNL. Microscopic enumeration was found to be unsuitable but the method based on MPO and lysozyme release from filter-associated PMNL was rapid, accurate and reproducible. Detectable PMNL migration (greater than 90%) occurred at 3-4 h and was maximal at 8-10 h. This pattern was observed for both the control and FMLP-containing systems. However, PMNL migration was significantly greater in FMLP-exposed dermis. FMLP at 10(-6) M was found to promote maximal PMNL migration. Significantly greater MPO and lysozyme activities were observed with the double filter system. This method is suitable for the objective quantitation of PMNL migration in vivo.

A comparison of the effects of tobramycin and netilmycin on the functions of human polymorphonuclear leucocytes and lymphocytes in vitro and in vivo

The effects of the antimicrobial agents tobramycin and netilmycin on the functions of human polymorphonuclear leucocytes (PMNLs) and on the mitogen-induced transformation of lymphocytes have been investigated both in vitro and in vivo before and 1 hour after a single intramuscular injection of the antibiotics. Neither antibiotic affected the migratory, phagocytic or antimicrobial capacities of PMNLs or the proliferative responses of lymphocytes to mitogens, at therapeutic concentrations or at 10-100-fold greater than therapeutic concentrations. Likewise, no alterations in these leucocyte functions accompanied the intramuscular injection of either antibiotic. neither tobramycin nor netilmycin therefore interferes with host immunodefence mechanisms.

Enhancement of human polymorphonuclear leucocyte motility by erythromycin in vitro and in vivo

The effects of erythromycin on the migration, phagocytosis and antimicrobial activity of human polymorphonuclear leucocytes (PMNLs) were investigated in vitro. Therapeutic concentrations of erythromycin potentiated PMNL staphylocidal activity without affecting phagocytosis. PMNL random motility and migration to leuco-attractant endotoxin-activated serum (EAS) were significantly enhanced by erythromycin at concentrations of greater than 5 x 10(-5)M (16,5 micrograms/ml). To assess the possible in vivo significance of these findings the same PMNL functions were investigated in healthy adult volunteers before and 90 minutes and 1 week after the ingestion of a single 500 mg tablet of erythromycin stearate. PMNL migration to EAS and antimicrobial activity were significantly increased after ingestion of erythromycin and eventually returned to normal levels. A single intraperitoneal injection of 1,5 mg erythromycin lactobionate significantly increased the mean survival time of mice experimentally infected with Candida albicans. These micro-organisms are resistant to the antimicrobial effects of erythromycin. These findings show that erythromycin possesses nonspecific immunopotentiating properties which may contribute to the antimicrobial activity of this antibiotic.

Studies on the effects of ingestion of a single 500 mg oral dose of erythromycin stearate on leucocyte motility and transformation and on release in vitro of prostaglandin E2 by stimulated leucocytes

Polymorphonuclear leucocyte (PMNL) and mononuclear leucocyte (MNL) migration to the leucoattractant endotoxin-activated serum as well as MNL mitogen-induced transformation were measured in normal adult volunteers before and 1 1/2 h and 96 h after the ingestion of a single oral dose of 500 mg of erythromycin stearate. Ingestion of the antibiotic was associated with a significant increase in PMNL migration at 1 1/2 h with a return to normal levels at 96 h. Slight but insignificant enhancement of MNL migration and of transformation to mitogens was detected after erythromycin. The mechanism of the slight stimulation of MNL transformation, which was consistently observed, was investigated further in vitro by measuring the effects of erythromycin base on the release of prostaglandin (PG) E2 by mitogen-stimulated MNL. Similar studies were performed using leuco-attractant-exposed PMNL. Inhibition of PGE2 release was observed for both MNL and PMNL with therapeutic concentrations of erythromycin. To assess the possible in-vivo significance of the immunopotentiating properties of the antibiotic the effect of a single intraperitoneal injection of 250, 500 or 1000 micrograms on the survival time of mice lethally infected with the erythromycin-resistant microorganism Candida albicans were investigated. Pre-treatment of the mice with erythromycin at each concentration used significantly increased the mean survival times. It is possible that these non-specific immunostimulatory properties of erythromycin potentiate in-vivo antimicrobial activity.