Effects of soil management systems on soil microbial activity, bulk density and chemical properties

The objective of this experiment was to study the effects of soil management systems on the bulk density, chemical soil properties, and on the soil microbial activity on a Latossolo Vermelho distrófico (Oxisol). Soil samples were collected from plots under the following management conditions: a) natural dense "cerrado" vegetation (savanna); b) degraded Brachiaria decumbens pasture, 20 years old; c) no-tillage treatment with annual crop sequence (bean, corn, soybean and dark-oat in continuous rotation), 8 years old; d) conventional tillage treatment with crop residues added to the soil, and annual crop sequence, 10 years old. The continuous use of no-tillage system resulted in an increase in microbial biomass and decrease in soil basal respiration, therefore displaying evident long-term effects on the increase of soil C content. The no-tillage system also provided an improvement in bulk density and chemical properties of the soil. Hence, the no-tillage management system could be an alternative for the conservation and maintenance of physical and chemical conditions and the productive potential of "cerrado" soils.

Affective and physiological responses to environmental noises and music

Research suggests that respiratory patterns may reflect general dimensions of emotional response. In this study, we investigated the relationships between judgments of affective valence (pleasantness) and arousal and respiratory responses to acoustic stimuli. Sixteen environmental noises and 16 musical fragments of 30 s duration were presented to 31 participants, while respiration, skin conductance level and heart rate were recorded. Judgments of valence and arousal were registered using the 9-point Self-Assessment Manikin. For noises, breathing accelerated and minute ventilation augmented with decreases in pleasantness for low-arousal stimuli and with increases in arousal for positive stimuli. For music, breathing accelerated and minute ventilation augmented with increases both in rated valence and arousal. Skin conductance level increased with arousal ratings for music but not for noises, whereas mean heart rate increased with rated arousal for noises but not for music. Although both noises and music are sound-vibrations, differences in the relationships between affective judgments and physiological responses were found suggesting differences in the processing of the two types of acoustic stimuli. [Authors]

Music Performance Anxiety (MPA) : cardiorespiratory activity in high- and low-anxious professional music students before a performance situation

Descriptors: music performance anxiety, respiration, hyperventilation Surveys indicate that high-anxious musicians may suffer from hyperventilation (HV) before or during performance. Reported symptoms include shortness of breath, fast/ deep breathing and thumping heart. However, no study has yet tested if these selfreported symptoms reflect actual cardiorespiratory activity. Themain goal of this study was to determine if MPA is manifested physiologically in specific correlates of cardiorespiratory activity associated with HV.We studied 74 professional music students from Swiss Music Academies. In this study, we compared the most anxious students (highanxious; n 5 20) with the least anxious students (low-anxious; n 5 23) based on their self-reported performance anxiety. We measured cardiorespiratory patterns with the Lifeshirt system, end-tidal CO2 with a capnograph (EtCO2, a good non-invasive estimator of HV), self-perceived physiological activation and affective experience in three situations on different days: baseline, performance without audience, and performance with audience. Comparing measures for the private vs. the public concert, high- compared to low-anxious students showed a significant drop in EtCO2 before the public concert and reported larger increases in anxiety, tension, palpitations and breathing difficulties. In contrast, heart rate, respiratory rate and volume did not differ significantly between groups. The results of this study support the hypothesis thatMPA may be associated with a tendency to hyperventilate and, thus, point to a potential hyperventilation problem in high-anxious music students.

Effects of paralysis with pancuronium bromide on joint mobility in premature infants.

To study the effects of muscle paralysis on joint mobility, we compared eight premature infants treated with pancuronium bromide with a control group. A significant reduction was observed in hip and knee flexion, and in ankle dorsal extension, which tended to resolve in time. We conclude that muscle paralysis reduces the mobility of selected joints; spontaneous activity appears to prevent long-term contractures.

Ripening and quality of 'Laetitia' plums following harvest and cold storage as affected by inhibition of ethylene action

The inhibition of ethylene action by 1-methylcyclopropene (1-MCP) extends shelf and storage life of many climacteric fruits. However, 1-MCP appears to have limited effects on stone fruit depending on specie and cultivar. The effects of 1-MCP on ripening and quality of 'Laetitia' plums were determined during ripening at 23ºC following harvest and cold storage. Japanese plums (Prunus salicina, cv. Laetitia) were harvested at mature pre-climacteric stage, cooled to 2ºC within 36 hours of harvest and then treated with 0, 0.05, 0.10, 0.50 or 1.00 muL L-1 of 1-MCP at 1°C for 24 hours. Following treatment, fruits were either held at 23ºC for 16 days or stored at 1ºC for 50 days. Fruits were removed from cold storage at 10-day intervals and allowed to ripe at 23°C for five days. A delay of climacteric respiration and ethylene production by 1-MCP treatment during ripening following harvest and cold storage was associated to a slow rate of fruit softening. 1-MCP treatment also delayed the loss of titratable acidity and changes of flesh and skin color, whereas it had little or no effect on soluble solids content. 1-MCP effects were concentration- and storage duration-dependent and, generally, a saturation fruit response to 1-MCP occurred between 0.5 and 1.0 muL L-1. During ripening, 1-MCP treated fruits attained quality similar to that of controls. Results indicated that 1-MCP treatment may extend shelf life (23ºC) and storage life (1ºC) of 'Laetitia' plums by approximately six and 20 days, respectively.

Mitochondrial dysfunction increases oxidative stress and decreases chronological life span in fission yeast

Background: Oxidative stress is a probable cause of aging and associated diseases. Reactive oxygen species (ROS) originate mainly from endogenous sources, namely the mitochondria. Methodology/Principal Findings: We analyzed the effect of aerobic metabolism on oxidative damage in Schizosaccharomyces pombe by global mapping of those genes that are required for growth on both respiratory-proficient media and hydrogen-peroxide-containing fermentable media. Out of a collection of approximately 2700 haploid yeast deletion mutants, 51 were sensitive to both conditions and 19 of these were related to mitochondrial function. Twelve deletion mutants lacked components of the electron transport chain. The growth defects of these mutants can be alleviated by the addition of antioxidants, which points to intrinsic oxidative stress as the origin of the phenotypes observed. These respiration-deficient mutants display elevated steady-state levels of ROS, probably due to enhanced electron leakage from their defective transport chains, which compromises the viability of chronologically-aged cells. Conclusion/Significance: Individual mitochondrial dysfunctions have often been described as the cause of diseases or aging, and our global characterization emphasizes the primacy of oxidative stress in the etiology of such processes.

Adaptation of aerobically growing Pseudomonas aeruginosa to copper starvation.

Restricted bioavailability of copper in certain environments can interfere with cellular respiration because copper is an essential cofactor of most terminal oxidases. The global response of the metabolically versatile bacterium and opportunistic pathogen Pseudomonas aeruginosa to copper limitation was assessed under aerobic conditions. Expression of cioAB (encoding an alternative, copper-independent, cyanide-resistant ubiquinol oxidase) was upregulated, whereas numerous iron uptake functions (including the siderophores pyoverdine and pyochelin) were expressed at reduced levels, presumably reflecting a lower demand for iron by respiratory enzymes. Wild-type P. aeruginosa was able to grow aerobically in a defined glucose medium depleted of copper, whereas a cioAB mutant did not grow. Thus, P. aeruginosa relies on the CioAB enzyme to cope with severe copper deprivation. A quadruple cyo cco1 cco2 cox mutant, which was deleted for all known heme-copper terminal oxidases of P. aeruginosa, grew aerobically, albeit more slowly than did the wild type, indicating that the CioAB enzyme is capable of energy conservation. However, the expression of a cioA'-'lacZ fusion was less dependent on the copper status in the quadruple mutant than in the wild type, suggesting that copper availability might affect cioAB expression indirectly, via the function of the heme-copper oxidases.

A randomized trial of glutamine and antioxidants in critically ill patients.

BACKGROUND: Critically ill patients have considerable oxidative stress. Glutamine and antioxidant supplementation may offer therapeutic benefit, although current data are conflicting. METHODS: In this blinded 2-by-2 factorial trial, we randomly assigned 1223 critically ill adults in 40 intensive care units (ICUs) in Canada, the United States, and Europe who had multiorgan failure and were receiving mechanical ventilation to receive supplements of glutamine, antioxidants, both, or placebo. Supplements were started within 24 hours after admission to the ICU and were provided both intravenously and enterally. The primary outcome was 28-day mortality. Because of the interim-analysis plan, a P value of less than 0.044 at the final analysis was considered to indicate statistical significance. RESULTS: There was a trend toward increased mortality at 28 days among patients who received glutamine as compared with those who did not receive glutamine (32.4% vs. 27.2%; adjusted odds ratio, 1.28; 95% confidence interval [CI], 1.00 to 1.64; P=0.05). In-hospital mortality and mortality at 6 months were significantly higher among those who received glutamine than among those who did not. Glutamine had no effect on rates of organ failure or infectious complications. Antioxidants had no effect on 28-day mortality (30.8%, vs. 28.8% with no antioxidants; adjusted odds ratio, 1.09; 95% CI, 0.86 to 1.40; P=0.48) or any other secondary end point. There were no differences among the groups with respect to serious adverse events (P=0.83). CONCLUSIONS: Early provision of glutamine or antioxidants did not improve clinical outcomes, and glutamine was associated with an increase in mortality among critically ill patients with multiorgan failure. (Funded by the Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00133978.).

Effets du traitement par CPAP sur la vigilance, la qualité de vie, l'inflammation et la pression artérielle chez les patients apnéiques

Contexte¦Le syndrome d'apnées/hypopnées obstructives du sommeil (SAHOS) est une maladie qui¦touche 4% des hommes et 2% des femmes entre 30 à 60 ans. Les patients touchés par le¦SAHOS ont deux problèmes principaux: premièrement, ils ont davantage de risque de¦développer une maladie cardiovasculaire. Deuxièmement, ils ont une diminution de la qualité¦de vie se présentant principalement sous forme de somnolence diurne et une perte de¦vigilance. Le meilleur traitement à l'heure actuelle est le CPAP (continuous positive airway¦pressure) qui permet de normaliser la respiration nocturne et d'améliorer la qualité du¦sommeil. Les effets favorables du CPAP sur la qualité de vie, la vigilance et l'inflammation¦ont été suggérés par plusieurs études mais restent controversés.¦Objectifs¦Évaluer l'effet de 6 semaines de traitement par CPAP sur la qualité de vie, la vigilance, la¦pression artérielle et l'inflammation (HsCRP).¦Méthodes¦Vingt-neuf patients connus pour un SAHOS ont été inclus dans cette étude. Les critères¦d'exclusions comprenaient une grossesse chez la femme, la présence de facteurs de risque¦cardiovasculaires ou d'une autre pathologie sévère.¦Les patients inclus dans l'étude ont tous été investigués, avant de débuter le traitement par¦CPAP, par un PVT (psychomotor vigilance test), un questionnaire de qualité de vie (SF-36),¦une polysomnographie, un dosage de l'hsCRP et par 2 prises de pression artérielle (avant et¦après la polysomnographie). Après ces examens, le traitement par CPAP a été introduit pour¦six semaines à l'issue desquelles les mêmes examens ont été répétés.¦Résultats¦L'étude montre tout d'abord une amélioration significative des paramètres concernant la¦vigilance : 1/temps de réaction (P = 0.01) et les oublis (P = 0.04). Ensuite, tous les paramètres¦de la santé mentale évalués par le questionnaire SF-36 s'améliorent significativement ainsi¦que le score global de santé physique. L'hsCRP évaluant l'inflammation montre une tendance¦à la diminution (P = 0.07). Quant à la pression artérielle, la pression systolique du soir¦diminue de manière significative et la pression systolique du matin et les deux tensions¦artérielles moyennes calculées montrent une tendance à la diminution.¦Conclusion¦Cette étude montre un effet bénéfique du CPAP chez les patients atteints de SAHOS au niveau¦de la vigilance et de la qualité de vie. Les effets sur la pression artérielle et l'inflammation ne¦sont toutefois pas complètement établis et restent encore sujet à débat.

Carbon and nitrogen partitioning during post-anthesis is conditioned by N fertilization and sink strength in three cereals

Further knowledge of the processes conditioning nitrogen use efficiency (NUE) is of great relevance to crop productivity. The aim of this paper was characterise C and N partitioning during grain filling and their implications for NUE. Cereals such as bread wheat (Triticum aestivum L. cv Califa sur), triticale (× Triticosecale Wittmack cv. Imperioso) and tritordeum (× Tritordeum Asch. & Graebn line HT 621) were grown under low (LN, 5 mm NH4NO3) and high (HN, 15 mm NH4NO3) N conditions. We conducted simultaneous double labelling (12CO2 and 15NH415NO3) in order to characterise C and N partitioning during grain filling. Although triticale plants showed the largest total and ear dry matter values in HN conditions, the large investment in shoot and root biomass negatively affected ear NUE. Tritordeum was the only genotype that increased NUE in both N treatments (NUEtotal), whereas in wheat, no significant effect was detected. N labelling revealed that N fertilisation during post-anthesis was more relevant for wheat and tritordeum grain filling than for triticale. The study also revealed that the investments of C and N in flag leaves and shoots, together with the"waste" of photoassimilates in respiration, conditioned the NUE of plants, and especially under LN. These results suggest that C and N use by these plants needs to be improved in order to increase ear C and N sinks, especially under LN. It is also remarkable that even though tritordeum shows the largest increase in NUE, the low yield of this cereal limits its agronomic value.

Acute respiratory syndrome after inhalation of waterproofing sprays: a posteriori exposure-response assessment in 102 cases

Waterproofing agents are widely used to protect leather and textiles in both domestic and occupational activities. An outbreak of acute respiratory syndrome following exposure to waterproofing sprays occurred during the winter 2002-2003 in Switzerland. About 180 cases were reported by the Swiss Toxicological Information Centre between October 2002 and March 2003, whereas fewer than 10 cases per year had been recorded previously. The reported cases involved three brands of sprays containing a common waterproofing mixture, that had undergone a formulation change in the months preceding the outbreak. A retrospective analysis was undertaken in collaboration with the Swiss Toxicological Information Centre and the Swiss Registries for Interstitial and Orphan Lung Diseases to clarify the circumstances and possible causes of the observed health effects. Individual exposure data were generated with questionnaires and experimental emission measurements. The collected data was used to conduct numeric simulation for 102 cases of exposure. A classical two-zone model was used to assess the aerosol dispersion in the near- and far-field during spraying. The resulting assessed dose and exposure levels obtained were spread on large scales, of several orders of magnitude. No dose-response relationship was found between exposure indicators and health effects indicators (perceived severity and clinical indicators). Weak relationships were found between unspecific inflammatory response indicators (leukocytes, C-reactive protein) and the maximal exposure concentration. The results obtained disclose a high interindividual response variability and suggest that some indirect mechanism(s) predominates in the respiratory disease occurrence. Furthermore, no threshold could be found to define a safe level of exposure. These findings suggest that the improvement of environmental exposure conditions during spraying alone does not constitute a sufficient measure to prevent future outbreaks of waterproofing spray toxicity. More efficient preventive measures are needed prior to the marketing and distribution of new waterproofing agents.

Characterization of polyphosphate synthesis by isolated yeast vacuoles

Polyphosphate (iPOP) is a linear polymer of orthophosphate units linked together by high energy phosphoanhydride bonds. It is found in all organisms, localized in organelles called acidocalcisomes and ranges from a few to few hundred monomers in length. iPOP has been found to play a vast array of roles in all organisms, including phosphate and energy metabolism, regulation of enzymes, virulence, pathogenicity, bone remodelling and blood clotting, among many others. Recently it was found that iPOP levels were increased in myeloma cells. The growing interest in iPOP in human cell lines makes it an interesting molecule to study. However, not much is known about its metabolism in eukaryotes. Acidocalcisomes are electron dense, acidic organelles that belong to the group of Lysosome Related Organelles (LROs). The conservation of acidocalcisomes among all kingdoms of life is suggestive of their important roles for the organisms. However, they are difficult to analyse because of limited biochemical tools for investigation. Yeast vacuoles present remarkable similarities to acidocalcisomes in terms of their physiological and structural features, including synthesis and storage of iPOP, which make them an ideal candidate to study biological processes which are shared between vacuoles and acidocalcisomes. The availability of tools for genetic manipulation and isolation of vacuoles makes yeast a candidate of choice for the characterization of iPOP synthesis in eukaryotes. Our group has identified the Vacuolar Transporter Chaperone (VTC) complex as iPOP polymerase and identified the catalytic subunit (Vtc4). The goal of my study was to characterize the process of iPOP synthesis by isolated vacuoles and to reconstitute iPOP synthesis in liposomes. The first step was to develop a method for monitoring iPOP by isolated vacuoles over time and comparing it with previously known methods. Next, a detailed characterization was performed to determine the modulators of the process, both for intact as well as solubilized vacuoles. Finally, attempts were made to purify the VTC complex and reconstitute it in liposomes. A parallel line of study was the translocation and storage of synthesized iPOP in the lumen of the vacuoles. As a result of this study, it is possible to determine distinct pools of iPOP- inside and outside the vacuolar lumen. Additionally, I establish that the vacuolar lysate withstands harsh steps during reconstitution on liposomes and retains iPOP synthesizing activity. The next steps will be purification of the intact VTC complex and its structure determination by cryo-electron microscopy. - Les organismes vivants sont composés d'une ou plusieurs cellules responsables des processus biologiques élémentaires tels que la digestion, la respiration, la synthèse et la reproduction. Leur environnement interne est en équilibre et ils réalisent un très grand nombre de réactions chimiques et biochimiques pour maintenir cet équilibre. A différents compartiments cellulaires, ou organelles, sont attribuées des tâches spécifiques pour maintenir les cellules en vie. L'étude de ces fonctions permet une meilleure compréhension de la vie et des organismes vivants. De nombreux processus sont bien connus et caractérisés mais d'autres nécessitent encore des investigations détaillées. L'un de ces processus est le métabolisme des polyphosphates. Ces molécules sont des polymères linéaires de phosphate inorganique dont la taille peut varier de quelques dizaines à quelques centaines d'unités élémentaires. Ils sont présents dans tous les organismes, des bactéries à l'homme. Ils sont localisés principalement dans des compartiments cellulaires appelés acidocalcisomes, des organelles acides observés en microscopie électronique comme des structures denses aux électrons. Les polyphosphates jouent un rôle important dans le stockage et le métabolisme de l'énergie, la réponse au stress, la virulence, la pathogénicité et la résistance aux drogues. Chez l'homme, ils sont impliqués dans la coagulation du sang et le remodelage osseux. De nouvelles fonctions biologiques des polyphosphates sont encore découvertes, ce qui accroît l'intérêt des chercheurs pour ces molécules. Bien que des progrès considérables ont été réalisés afin de comprendre la fonction des polyphosphates chez les bactéries, ce qui concerne la synthèse, le stockage et la dégradation des polyphosphates chez les eucaryotes est mal connu. Les vacuoles de la levure Saccharomyces cerevisiae sont similaires aux acidocalcisomes des organismes supérieurs en termes de structure et de fonction. Les acidocalcisomes sont difficiles à étudier car il n'existe que peu d'outils génétiques et biochimiques qui permettent leur caractérisation. En revanche, les vacuoles peuvent être aisément isolées des cellules vivantes et manipulées génétiquement. Les vacuoles comme les acidocalcisomes synthétisent et stockent les polyphosphates. Ainsi, les découvertes faites grâce aux vacuoles de levures peuvent être extrapolées aux acidocalcisomes des organismes supérieurs. Le but de mon projet était de caractériser la synthèse des polyphosphates par des vacuoles isolées. Au cours de mon travail de thèse, j'ai mis au point une méthode de mesure de la synthèse des polyphosphates par des organelles purifés. Ensuite, j'ai identifié des composés qui modulent la réaction enzymatique lorsque celle-ci a lieu dans la vacuole ou après solubilisation de l'organelle. J'ai ainsi pu mettre en évidence deux groupes distincts de polyphosphates dans le système : ceux au-dehors de la vacuole et ceux en-dedans de l'organelle. Cette observation suggère donc très fortement que les vacuoles non seulement synthétisent les polyphosphates mais aussi transfère les molécules synthétisées de l'extérieur vers l'intérieur de l'organelle. Il est très vraisemblable que les vacuoles régulent le renouvellement des polyphosphates qu'elles conservent, en réponse à des signaux cellulaires. Des essais de purification de l'enzyme synthétisant les polyphosphates ainsi que sa reconstitution dans des liposomes ont également été entrepris. Ainsi, mon travail présente de nouveaux aspects de la synthèse des polyphosphates chez les eucaryotes et les résultats devraient encourager l'élucidation de mécanismes similaires chez les organismes supérieurs. - Les polyphosphates (iPOP) sont des polymères linéaires de phosphates inorganiques liés par des liaisons phosphoanhydres de haute énergie. Ces molécules sont présentes dans tous les organismes et localisées dans des compartiments cellulaires appelés acidocalcisomes. Elles varient en taille de quelques dizaines à quelques centaines d'unités phosphate. Des fonctions nombreuses et variées ont été attribuées aux iPOP dont un rôle dans les métabolismes de l'énergie et du phosphate, dans la régulation d'activités enzymatiques, la virulence, la pathogénicité, le remodelage osseux et la coagulation sanguine. Il a récemment été montré que les cellules de myélome contiennent une grande quantité de iPOP. Il y donc un intérêt croissant pour les iPOP dans les lignées cellulaires humaines. Cependant, très peu d'informations sur le métabolisme des iPOP chez les eucaryotes sont disponibles. Les acidocalcisomes sont des compartiments acides et denses aux électrons. Ils font partie du groupe des organelles similaires aux lysosomes (LROs pour Lysosome Related Organelles). Le fait que les acidocalcisomes soient conservés dans tous les règnes du vivant montrent l'importance de ces compartiments pour les organismes. Cependant, l'analyse de ces organelles est rendue difficile par l'existence d'un nombre limité d'outils biochimiques permettant leur caractérisation. Les vacuoles de levures possèdent des aspects structuraux et physiologiques très similaires à ceux des acidocalcisomes. Par exemple, ils synthétisent et gardent en réserve les iPOP. Ceci fait des vacuoles de levure un modèle idéal pour l'étude de processus biologiques conservés chez les vacuoles et les acidocalcisomes. De plus, la levure est un organisme de choix pour l'étude de la synthèse des iPOP compte-tenu de l'existence de nombreux outils génétiques et la possibilité d'isoler des vacuoles fonctionnelles. Notre groupe a identifié le complexe VTC (Vacuole transporter Chaperone) comme étant responsable de la synthèse des iPOP et la sous-unité Vtc4p comme celle possédant l'activité catalytique. L'objectif de cette étude était de caractériser le processus de synthèse des iPOP en utilisant des vacuoles isolées et de reconstituer la synthèse des iPOP dans des liposomes. La première étape a consisté en la mise au point d'un dosage permettant la mesure de la quantité de iPOP synthétisés par les organelles isolés en fonction du temps. Cette nouvelle méthode a été comparée aux méthodes décrites précédemment dans la littérature. Ensuite, la caractérisation détaillée du processus a permis d'identifier des composés modulateurs de la réaction à la fois pour des vacuoles intactes et des vacuoles solubilisées. Enfin, des essais de purification du complexe VTC et sa reconstitution dans des liposomes ont été entrepris. De façon parallèle, une étude sur la translocation et le stockage des iPOP dans le lumen des vacuoles a été menée. Il a ainsi été possible de mettre en évidence différents groupes de iPOP : les iPOP localisés à l'intérieur et ceux localisés à l'extérieur des vacuoles isolées. De plus, nous avons observé que le lysat vacuolaire n'est pas détérioré par les étapes de reconstitution dans les liposomes et conserve l'activité de synthèse des iPOP. Les prochaines étapes consisteront en la purification du complexe intact et de la détermination de sa structure par cryo-microscopie électronique.

The impact of spatial resolution and respiratory motion on MR imaging of atherosclerotic plaque.

PURPOSE: To examine the impact of spatial resolution and respiratory motion on the ability to accurately measure atherosclerotic plaque burden and to visually identify atherosclerotic plaque composition. MATERIALS AND METHODS: Numerical simulations of the Bloch equations and vessel wall phantom studies were performed for different spatial resolutions by incrementally increasing the field of view. In addition, respiratory motion was simulated based on a measured physiologic breathing pattern. RESULTS: While a spatial resolution of > or = 6 pixels across the wall does not result in significant errors, a resolution of < or = 4 pixels across the wall leads to an overestimation of > 20%. Using a double-inversion T2-weighted turbo spin echo sequence, a resolution of 1 pixel across equally thick tissue layers (fibrous cap, lipid, smooth muscle) and a respiratory motion correction precision (gating window) of three times the thickness of the tissue layer allow for characterization of the different coronary wall components. CONCLUSIONS: We found that measurements in low-resolution black blood images tend to overestimate vessel wall area and underestimate lumen area.

Residuelle Lungenfunktionsveränderungen nach "Adult Respiratory Distress Syndrome" (ARDS) bei Kindern [Residual lung function changes following adult respiratory distress syndrome (ARDS) in children]

Residual lung function abnormalities have been investigated in 9 children (4 boys and 5 girls) a mean 2.7 years after surviving severe adult respiratory distress syndrome (ARDS). All patients had been artificially ventilated for an average of 9.4 days with a FiO2 greater than 0.5 for 34 hours and maximal PEEP levels in the range of 8-20 cm H2O. Since the ARDS, 3 children had presented recurrent respiratory symptoms (moderate exertional dyspnea and cough) and 2 had had evidence of fibrosis on chest radiographs. In all patients abnormal lung functions were found, i.e. ventilation inequalities (8), hypoxemia (7), and obstructive (2) and restrictive (1) lung disease. A significant correlation between respirator therapy and residual lung function was found (duration of FiO2 greater than 0.5 in hours and inspiratory plateau pressure during respirator therapy vs. ventilation inequalities and hypoxemia).

Resistance of stored-product insects to phosphine

The objectives of this work were to assess phosphine resistance in insect populations (Tribolium castaneum, Rhyzopertha dominica, Sitophilus zeamais and Oryzaephilus surinamensis) from different regions of Brazil and to verify if the prevailing mechanism of phosphine resistance in these populations involves reduced respiration rates. Sixteen populations of T. castaneum, 15 of R. dominica, 27 of S. zeamais and eight of O. surinamensis were collected from 36 locations over seven Brazilian states. Each population was tested for resistance to phosphine, based on the response of adults to discriminating concentrations, according to FAO standard method. For each insect species, the production of carbon dioxide of the most resistant and of the most susceptible populations was inversely related to their phosphine resistance. The screening tests identified possible phosphine resistant populations. R. dominica and O. surinamensis were less susceptible to phosphine than the other two species. The populations with lower respiration rate showed a lower mortality at discriminating concentration, possibly related to a phosphine resistance mechanism. Phosphine resistance occurs in stored-product insects, in different regions of Brazil, and the resistance mechanism involves reduced respiration rate.