Anadenanthera colubrina (Fabaceae) logs in the Atlantic Forest biome: first host plant for Thoracibidion lineatocolle (Col: Cerambycidae) and a new host for Temnopis megacephala (Col: Cerambycidae) / Troncos de Anadenanthera colubrina (Fabaceae) no bioma da Mata Atlântica: primeira planta hospedeira de Thoracibidion lineatocolle (Col: Cerambycidae) e uma nova planta hospedeira para Temnopis megacephala (Col: Cerambycidae)

Wood-boring beetles develop in live trees and dead wood, performing ecological services such as decomposition and regulation of forest resources. Species of the Cerambycidae family, widely distributed in the world, bore into the trunks of trees and dead wood in native and cultivated areas. The objective is to report the first host plant for Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) and a new host plant for Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) in the Brazilian Atlantic Forest biome. Three logs, with one-meter-long by 20 cm in diameter, were cut from the trunk of a healthy Anadenanthera colubrina (Fabaceae) tree in October 2013 and tied in the understory at 1.5m high in the Rio Doce State Park, Minas Gerais State, Brazil. The logs, exposed in the forest, were each removed after 40, 80 and 120 days and stored individually in a cardboard box in the "Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)" in the Rio Doce State Park. A total of 94 individuals of T. lineatocolle and 228 of T. megacephala emerged from the A. colubrina logs. This is the first report of a host plant for T. lineatocolle and a new host plant for T. megacephala.

Besouros broqueadores se desenvolvem em árvores vivas e madeira morta, realizando serviços ecológicos como decomposição e regulação de recursos da floresta. Espécies da família Cerambycidae, amplamente distribuídas no mundo, perfuram o caule de árvores e madeira morta em áreas nativas e cultivadas. O objetivo é relatar a primeira planta hospedeira de Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) e uma nova planta hospedeira para Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) no bioma da Mata Atlântica brasileira. Três toras, com um metro de comprimento por 20 cm de diâmetro, foram cortadas de uma árvore sadia de Anadenanthera colubrina (Fabaceae) em outubro de 2013 e amarradas no sub-bosque a 1,5m de altura no Parque Estadual do Rio Doce, estado de Minas Gerais, Brasil. As toras, expostas na floresta, foram removidas, cada uma, após 40, 80 e 120 dias e armazenadas, individualmente, em caixas de papelão no “Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)” no Parque Estadual do Rio Doce. Um total de 94 indivíduos de T. lineatocolle e 228 de T. megacephala emergiu das toras de A. colubrina. Esse é o primeiro registro de uma planta hospedeira para T. lineatocolle e o de uma nova planta hospedeira para T. megacephala.

Anadenanthera colubrina (Fabaceae) logs in the Atlantic Forest biome: first host plant for Thoracibidion lineatocolle (Col.: Cerambycidae) and a new host for Temnopis megacephala (Col.: Cerambycidae)

Abstract Wood-boring beetles develop in live trees and dead wood, performing ecological services such as decomposition and regulation of forest resources. Species of the Cerambycidae family, widely distributed in the world, bore into the trunks of trees and dead wood in native and cultivated areas. The objective is to report the first host plant for Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) and a new host plant for Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) in the Brazilian Atlantic Forest biome. Three logs, with one-meter-long by 20 cm in diameter, were cut from the trunk of a healthy Anadenanthera colubrina (Fabaceae) tree in October 2013 and tied in the understory at 1.5m high in the Rio Doce State Park, Minas Gerais State, Brazil. The logs, exposed in the forest, were each removed after 40, 80 and 120 days and stored individually in a cardboard box in the Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq) in the Rio Doce State Park. A total of 94 individuals of T. lineatocolle and 228 of T. megacephala emerged from the A. colubrina logs. This is the first report of a host plant for T. lineatocolle and a new host plant for T. megacephala.

Resumo Besouros broqueadores se desenvolvem em árvores vivas e madeira morta, realizando serviços ecológicos como decomposição e regulação de recursos da floresta. Espécies da família Cerambycidae, amplamente distribuídas no mundo, perfuram o caule de árvores e madeira morta em áreas nativas e cultivadas. O objetivo é relatar a primeira planta hospedeira de Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) e uma nova planta hospedeira para Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) no bioma da Mata Atlântica brasileira. Três toras, com um metro de comprimento por 20 cm de diâmetro, foram cortadas de uma árvore sadia de Anadenanthera colubrina (Fabaceae) em outubro de 2013 e amarradas no sub-bosque a 1,5m de altura no Parque Estadual do Rio Doce, estado de Minas Gerais, Brasil. As toras, expostas na floresta, foram removidas, cada uma, após 40, 80 e 120 dias e armazenadas, individualmente, em caixas de papelão no Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq) no Parque Estadual do Rio Doce. Um total de 94 indivíduos de T. lineatocolle e 228 de T. megacephala emergiu das toras de A. colubrina. Esse é o primeiro registro de uma planta hospedeira para T. lineatocolle e o de uma nova planta hospedeira para T. megacephala.

Anadenanthera colubrina (Fabaceae) logs in the Atlantic Forest biome: first host plant for Thoracibidion lineatocolle (Col: Cerambycidae) and a new host for Temnopis megacephala (Col: Cerambycidae) / Troncos de Anadenanthera colubrina (Fabaceae) no bioma da Mata Atlântica: primeira planta hospedeira de Thoracibidion lineatocolle (Col: Cerambycidae) e uma nova planta hospedeira para Temnopis megacephala (Col: Cerambycidae)

Wood-boring beetles develop in live trees and dead wood, performing ecological services such as decomposition and regulation of forest resources. Species of the Cerambycidae family, widely distributed in the world, bore into the trunks of trees and dead wood in native and cultivated areas. The objective is to report the first host plant for Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) and a new host plant for Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) in the Brazilian Atlantic Forest biome. Three logs, with one-meter-long by 20 cm in diameter, were cut from the trunk of a healthy Anadenanthera colubrina (Fabaceae) tree in October 2013 and tied in the understory at 1.5m high in the Rio Doce State Park, Minas Gerais State, Brazil. The logs, exposed in the forest, were each removed after 40, 80 and 120 days and stored individually in a cardboard box in the "Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)" in the Rio Doce State Park. A total of 94 individuals of T. lineatocolle and 228 of T. megacephala emerged from the A. colubrina logs. This is the first report of a host plant for T. lineatocolle and a new host plant for T. megacephala.

Besouros broqueadores se desenvolvem em árvores vivas e madeira morta, realizando serviços ecológicos como decomposição e regulação de recursos da floresta. Espécies da família Cerambycidae, amplamente distribuídas no mundo, perfuram o caule de árvores e madeira morta em áreas nativas e cultivadas. O objetivo é relatar a primeira planta hospedeira de Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) e uma nova planta hospedeira para Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) no bioma da Mata Atlântica brasileira. Três toras, com um metro de comprimento por 20 cm de diâmetro, foram cortadas de uma árvore sadia de Anadenanthera colubrina (Fabaceae) em outubro de 2013 e amarradas no sub-bosque a 1,5m de altura no Parque Estadual do Rio Doce, estado de Minas Gerais, Brasil. As toras, expostas na floresta, foram removidas, cada uma, após 40, 80 e 120 dias e armazenadas, individualmente, em caixas de papelão no "Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)" no Parque Estadual do Rio Doce. Um total de 94 indivíduos de T. lineatocolle e 228 de T. megacephala emergiu das toras de A. colubrina. Esse é o primeiro registro de uma planta hospedeira para T. lineatocolle e o de uma nova planta hospedeira para T. megacephala.

Anadenanthera colubrina (Fabaceae) logs in the Atlantic Forest biome: first host plant for Thoracibidion lineatocolle (Col.: Cerambycidae) and a new host for Temnopis megacephala (Col.: Cerambycidae).

Wood-boring beetles develop in live trees and dead wood, performing ecological services such as decomposition and regulation of forest resources. Species of the Cerambycidae family, widely distributed in the world, bore into the trunks of trees and dead wood in native and cultivated areas. The objective is to report the first host plant for Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) and a new host plant for Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) in the Brazilian Atlantic Forest biome. Three logs, with one-meter-long by 20 cm in diameter, were cut from the trunk of a healthy Anadenanthera colubrina (Fabaceae) tree in October 2013 and tied in the understory at 1.5m high in the Rio Doce State Park, Minas Gerais State, Brazil. The logs, exposed in the forest, were each removed after 40, 80 and 120 days and stored individually in a cardboard box in the "Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)" in the Rio Doce State Park. A total of 94 individuals of T. lineatocolle and 228 of T. megacephala emerged from the A. colubrina logs. This is the first report of a host plant for T. lineatocolle and a new host plant for T. megacephala.

Gram-negative bacteria associated with a dominant arboreal ant species outcompete phyllosphere-associated bacteria species in a tropical canopy.

Ants have efficient and well-studied social immunity mechanisms, which prevent the colony contamination. Little is known about how workers keep their outside territory clear of diseases. We investigated the interactions between Azteca chartifex ants, their associated bacteria and bacteria on the phyllosphere of Byrsonima sericea trees, comparing plants patrolled and not by the ants. The hypothesis is that bacteria associated with the worker's exoskeleton may outcompete the leaf bacteria. Culturable bacteria were isolated from ants, from the main and satellite nests, and from phyllosphere of B. sericea taken from trees that had A. chartifex nests and from trees without nests. The isolates were grouped by Gram guilds and identified at the genus level. There was a higher percentage of Gram-negative isolates in the ants and on the leaves patrolled by them. There was a higher growth rate of ant bacteria from the main nest compared to those found in ants from the satellite nests. The most representative genus among ant isolates was Enterobacter, also found on leaves patrolled by ants. Under favourable in vitro conditions, A. chartifex Gram-negative bacteria outcompete leaf bacteria by overgrowth, showing a greater competition capacity over the Gram-positive bacteria from leaves with no previous interaction with ants in the field. It was demonstrated that ants carry bacteria capable of outcompeting exogenous bacteria associated with their outside territory. The leaf microbiota of a patrolled tree could be shaped by the ant microbiota, suggesting that large ant colonies may have a key role in structuring canopy plant-microbe interactions.

Cross-Sectional Imaging of Third Molar-Related Abnormalities.

Third molars may be associated with a wide range of pathologic conditions, including mechanical, inflammatory, infectious, cystic, neoplastic, and iatrogenic. Diagnosis of third molar-related conditions can be challenging for radiologists who lack experience in dental imaging. Appropriate imaging evaluation can help practicing radiologists arrive at correct diagnoses, thus improving patient care. This review discusses the imaging findings of various conditions related to third molars, highlighting relevant anatomy and cross-sectional imaging techniques. In addition, key imaging findings of complications of third molar extraction are presented.

Analysis of iron superoxide dismutase-encoding DNA vaccine on the evolution of the Leishmania amazonensis experimental infection.

The present work aimed to evaluate the immunogenicity of Leishmania amazonensis iron superoxide dismutase (SOD)-encoding DNA experimental vaccine and the protective properties of this DNA vaccine during infection. The SOD gene was subcloned into the pVAX1 plasmid, and it was used to immunize BALB/c mice. Twenty-one days after the last immunization, mice were sacrificed (immunogenicity studies) or subcutaneously challenged with L. amazonensis (studies of protection), and alterations in cellular and humoral immune responses were evaluated, as well as the course of infection. Mice only immunized with pVAX1-SOD presented increased frequencies of CD4(+) IFN-γ(+), CD8(+)IFN-γ(+) and CD8(+)IL-4(+) lymphocytes; moreover, high levels of IgG2a were detected. After challenge, mice that were immunized with pVAX1-SOD had increased frequencies of the CD4(+)IL-4(+), CD8(+)IFN-γ(+) and CD8(+)IL-4(+) T lymphocytes. In addition, the lymph node cells produced high amounts of IFN-γ and IL-4 cytokines. Increased IgG2a was also detected. The pattern of immunity induced by pVAX1-SOD partially protected the BALB/c mice from a challenge with L. amazonensis, as the animals presented reduced parasitism and lesion size when compared to controls. Taken together, these results indicate that leishmanial SOD modulates the lymphocyte response, and that the elevation in IFN-γ possibly accounted for the decreased skin parasitism observed in immunized animals.

Evidences that human disturbance simplify the ant fauna associated a Stachytarpheta glabra Cham. (Verbenaceae) compromising the benefits of ant-plant mutualism.

Interaction among species, like ants and plants through extrafloral nectaries (EFNs), are important components of ecological communities' evolution. However, the effect of human disturbance on such specific interactions and its ecological consequences is poorly understood. This study evaluated the outcomes of mutualism between ants and the EFN-bearing plant Stachytarpheta glabra under anthropogenic disturbance. We compared the arthropod fauna composition between two groups of twenty plant individuals, one in an area disturbed by human activities and one in a preserved area. We also check the plant investment in herbivory defense and the consequential leaf damage by herbivore. Our results indicate that such disturbances cause simplification of the associated fauna and lack of proper ant mutualist. This led to four times more herbivory on plants of disturbed areas, despite the equal amount of EFN and ant visitors and low abundance of herbivores. The high pressure of herbivory may difficult the re-establishment of S. glabra, an important pioneer species in ferruginous fields, therefore it may affect resilience of this fragile ecological community.

Are ant assemblages of Brazilian veredas characterised by location or habitat type?

Wetland areas in the Brazilian Cerrado, known as "veredas", represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species. Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted "veredas". Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat.

Heat stress attenuates ventilator-induced lung dysfunction in an ex vivo rat lung model.

Our laboratory has previously shown decreased mortality rates and the attenuation of lung injury in rats exposed to heat stress (H) 18 h prior to induction of sepsis. In the present study, we examined the hypothesis that heat stress would protect lungs against ventilator-induced lung injury. Male Sprague-Dawley rats were anesthetized and randomly allocated to receive either sham treatment or exposure to heat (rectal temperature 41 degrees C, for 15 min). The lungs were harvested 18 h later, a pressure-volume (P- V) curve was constructed, and the lungs were either lavaged for cytokine and surfactant analyses (preventilation data) or were mechanically ventilated with VT 40 ml/kg in a warmed, humidified chamber. After 2 h of mechanical ventilation, another P-V curve was constructed and the lungs were lavaged for cytokine and surfactant analyses (postventilation data). Mechanical ventilation in control lungs produced a 47% decrease in chord compliance, an increase in lung lavage levels of tumor necrosis factor (TNF)-alpha (722 +/- 306 pg/ml), interleukin (IL)-1beta (902 +/- 322 pg/ml), and macrophage inflammatory protein-2 (MIP-2) (363 +/- 104 pg/ml) as compared with low levels of cytokines detected in preventilation data, and no change in percentage of surfactant large aggregates (LA). In contrast, in mechanically ventilated lungs from animals that were exposed to heat stress we observed a smaller decrease in chord compliance (17%), a significant attenuation in cytokine levels (TNF-alpha 233 +/- 119 pg/ml; IL-1beta 124 +/- 53 pg/ml; MIP-2 73 +/- 52 pg/ml; p < 0.05) and a significant increase in percentage LA compared with control animals. We conclude that exposing animals to heat stress confers protection against the effects of an injurious form of mechanical ventilation, by a mechanism that may involve attenuation of cytokines and preservation of some surfactant properties.

Heat stress increases survival rates in lipopolysaccharide-stimulated rats.

OBJECTIVE: To examine the hypothesis that heat stress applied after the administration of bacterial endotoxin is protective. DESIGN: Prospective, randomized, laboratory study. SETTING: University research laboratory. SUBJECTS: One hundred eleven adult male Sprague-Dawley rats (weight range 250 to 400 g). INTERVENTIONS: Production of endotoxemia by the administration of a bacterial endotoxin and exposure to heat stress by heating animals in a neonatal incubator until their rectal temperatures reached 105.8 degrees F (41 degrees C). MEASUREMENTS AND MAIN RESULTS: The rats (n = 111) were anesthetized and were injected with 15 mg/kg of Escherichia coli endotoxin (lipopolysaccharide, LPS) intravenously to produce septic shock. Immediately thereafter, a set of 50 rats were randomly assigned to one of two treatment groups: a) LPS-treated (control); or b) LPS-treated and heated to 105.8 degrees F (41 degrees C). The animals were then observed for the development of fever, and survival rates were monitored for 72 hrs. In another set of 40 animals, the same experimental protocol was used to determine plasma cytokine concentrations in heated and nonheated groups. Blood samples were obtained at 0, 2, 4, or 6 hrs after LPS injection for tumor necrosis factor-alpha and interleukin (IL)-1 beta detection. In a third set of animals, the same experimental protocol was applied to nine animals for the detection of heat-shock proteins of 72-kilodalton molecular weight. LPS injection in the control group did not produce fever. Heat stress increased the abundance of heat-shock proteins of 72-kilodalton molecular weight in the rats' lungs (analysis of variance, p = .016). Twelve hours after the initiation of sepsis, the survival rates of the control group injected with LPS alone and the group heated to 105.8 degrees F (41 degrees C) were 48% and 80%, respectively (p = .039). The peak plasma IL-1 beta concentrations occurring at 2 hrs after LPS injection were significantly reduced in rats heated to 105.8 degrees F (41 degrees C) when compared with nonheated rats (p = .003). CONCLUSION: We conclude that heat stress applied after the initiation of endotoxemia can provide protection against an otherwise lethal stimulus and that the mechanism of protection may be related to the attenuation of plasma IL-1 beta concentrations.

Injurious ventilatory strategies increase cytokines and c-fos m-RNA expression in an isolated rat lung model.

We examined the effect of ventilation strategy on lung inflammatory mediators in the presence and absence of a preexisting inflammatory stimulus. 55 Sprague-Dawley rats were randomized to either intravenous saline or lipopolysaccharide (LPS). After 50 min of spontaneous respiration, the lungs were excised and randomized to 2 h of ventilation with one of four strategies: (a) control (C), tidal volume (Vt) = 7 cc/kg, positive end expiratory pressure (PEEP) = 3 cm H2O; (b) moderate volume, high PEEP (MVHP), Vt = 15 cc/kg; PEEP = 10 cm H2O; (c) moderate volume, zero PEEP (MVZP), Vt = 15 cc/kg, PEEP = 0; or (d) high volume, zero PEEP (HVZP), Vt = 40 cc/kg, PEEP = 0. Ventilation with zero PEEP (MVZP, HVZP) resulted in significant reductions in lung compliance. Lung lavage levels of TNFalpha, IL-1beta, IL-6, IL-10, MIP-2, and IFNgamma were measured by ELISA. Zero PEEP in combination with high volume ventilation (HVZP) had a synergistic effect on cytokine levels (e.g., 56-fold increase of TNFalpha versus controls). Identical end inspiratory lung distention with PEEP (MVHP) resulted in only a three-fold increase in TNFalpha, whereas MVZP produced a six-fold increase in lavage TNFalpha. Northern blot analysis revealed a similar pattern (C, MVHP < MVZP < HVZP) for induction of c-fos mRNA. These data support the concept that mechanical ventilation can have a significant influence on the inflammatory/anti-inflammatory milieu of the lung, and thus may play a role in initiating or propagating a local, and possibly systemic inflammatory response.

Effects of the stress response in septic rats and LPS-stimulated alveolar macrophages: evidence for TNF-alpha posttranslational regulation.

We have previously demonstrated that induction of the stress response, by heat stress or sodium arsenite, administered 18 h before initiation of sepsis in rats, significantly decreased mortality and lung injury. As a possible mechanism underlying this effect, we hypothesized that the induction of the stress response, prior to bacterial endotoxin (lipopolysaccharide, LPS) stimulation, would cause a decrease in synthesis and/or release of tumor necrosis factor-alpha (TNF-alpha), making the animals more resistant to sepsis. Rats exposed to Salmonella typhosa LPS demonstrated a rise in plasma TNF-alpha. In contrast, rats exposed to heat stress or to sodium arsenite 18 h prior to LPS had significantly lower levels of plasma TNF-alpha. To examine the mechanisms by which the stress response mediates this decrease, we studied cultured alveolar macrophages. Similar to in vivo studies, TNF released into supernatants of alveolar macrophages treated with LPS was significantly higher than from cells exposed to the stress response prior to LPS. The decrease in TNF-alpha protein release was not accompanied by a similar decrease in TNF-alpha mRNA levels or by a decrease in cell-associated TNF-alpha, suggesting possible posttranslational regulation of TNF-alpha. To determine whether the decrease in TNF-alpha release was due to binding and sequestration by heat shock proteins (HSP), TNF-alpha was purified by immunoprecipitation. Under these conditions, TNF-alpha and HSP72kDa coprecipitated from cells that had received stress treatment prior to LPS. These data implicate HSP in posttranslational control of TNF-alpha release in LPS-stimulated alveolar macrophages exposed to the stress response.

Heat shock-sensitive expression of calreticulin. In vitro and in vivo up-regulation.

Calreticulin (CRT) is an ubiquitous, highly conserved, Ca(2+)-binding protein of the sarcoplasmic and endoplasmic reticulum. The precise function(s) of CRT is unknown. However, based on sequence analyses and observations that it may bind to steroid receptors and integrins and store Ca2+ within the cell, it has been postulated to play a "housekeeping" role. To determine whether the level of expression of CRT is affected by stress, we examined the heat shock response of CRT from a variety of cultured cells, including vascular endothelial, lung epithelial, and lung fibroblasts. Following exposure of the cells to 42 degrees C, CRT mRNA transiently accumulated 2.5-4.2-fold at 1-6 h. Nuclear run-on studies and mRNA stability experiments confirmed that the predominant mechanism of augmentation was transcriptional. Chloramphenicol acetyltransferase assays further indicated that the promoter region, containing a putative heat shock element between -172 and -158 of the human CRT gene, is heat shock-sensitive. Finally, we demonstrated the in vivo significance of these findings by exposing rats to hyperthermia. This resulted in accumulation of CRT mRNA and an augmentation of CRT protein in lung tissue. We hypothesize that this stress-induced up-regulation of CRT contributes to the mechanism(s) by which the vascular endothelium and lung tissue, and possibly other organ systems, maintain homeostasis when exposed to a variety of pathophysiological conditions.

Induction of the stress response to prevent organ injury.

Septic shock, multiorgan dysfunction, and the acute respiratory distress syndrome are major contributors to morbidity and mortality in the ICU setting. Animal studies have shown that these forms of injury can be attenuated or prevented if a phenomenon, called the stress response, is activated. The stress response, characterized by a transient downregulation of most cellular products and by the upregulation of the heat-shock proteins (HSPs), has been shown to provide protection to cells and experimental animals if triggered prior to an otherwise lethal injury. The mechanisms by which the stress response is protective are not known with certainty, but HSPs appear to play an important role. HSPs are constitutively present in all cells studied to date and can also be induced by artificial fever and by nonthermal means. They act as molecular chaperones, interacting transiently with newly synthesized proteins and proteins experiencing difficulty in proper folding. HSPs also escort and help proteins to cross membranes. This chaperone function is essential for cellular protection since it provides a mechanism by which defective polypeptides may be directed to lisosomes for degradation. This article summarizes the current literature on the effects of the stress response in protecting cells and animals from lethal forms of systemic and organ damage.

Increased nitric oxide in exhaled gas as an early marker of lung inflammation in a model of sepsis.

Nitric Oxide (NO) has been implicated in the pathologic vasodilation of sepsis. Because NO can be measured in the exhaled gas of animals and humans, we hypothesized that increases in exhaled NO would occur in a septic model. Using a blinded design, 10 male Sprague-Dawley rats (300 to 400 g) were anesthetized, paralyzed, tracheotomized, and randomized (5/group) to receive an intravenous injection of either lipopolysaccharide (LPS) (Salmonella typhosa, 20 mg/kg) or placebo (equal volume of saline). Thereafter, exhaled gas was collected and measurements of NO concentration were made using chemiluminescence every 20 min for 300 min during ventilation (RR 40 breaths/min, VT 3 ml; PEEP 0, FIO2 0.21). Another group of 10 animals (5 LPS; 5 control) were treated in the same fashion and then killed at 240 min and an arterial blood sample obtained for blood gas and TNF alpha determinations. Pressure volume (PV) curves were constructed and lungs removed, preserved, and submitted for histologic evaluation. LPS-treated rats had lower mean arterial pressures than the control group, p < 0.0001. No significant differences in static lung compliance and PV curves were found in the two groups. TNF alpha levels were greater in the LPS group (1.40 +/- 0.24 ng/ml) versus control group (0.09 +/- 0.04 ng/ml), p < 0.001. By contrast to the control group, exhaled NO concentration rose in all LPS-treated rats at approximately 100 min and at about 160 min reached a plateau that was 6 times greater than control levels (p < 0.0001). There was greater interstitial, airspace, and total lung injury in the LPS group (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium arsenite induces heat shock protein-72 kilodalton expression in the lungs and protects rats against sepsis.

OBJECTIVE: To examine the hypothesis that induction of heat shock proteins by a nonthermal mechanism would confer protection against experimental sepsis. DESIGN: Prospective, blind, randomized, laboratory study. SETTING: University research laboratory. SUBJECTS: Sixty-two adult male Sprague-Dawley rats (weight range 250 to 350 g). INTERVENTIONS: Administration of sodium arsenite or saline in an animal model of sepsis by cecal ligation and perforation. MEASUREMENTS AND MAIN RESULTS: Sixty-two rats were randomly divided into two groups: group 1 received sodium arsenite (6 mg/kg iv) and group 2 received saline injection, in a blinded fashion. Eighteen hours after receiving sodium arsenite or saline, cecal ligation and perforation were performed and the animals were monitored for mortality for 96 hrs. Sodium arsenite injection, in the absence of an increase in body temperature, induced heat shock protein of 72-kilodalton molecular weight expression in the lung, which was detected 2 hrs after injection, peaked between 9 and 24 hrs, and returned to baseline by 48 hrs. Prior administration of sodium arsenite conferred significant protection against cecal ligation and perforation-induced mortality at 18 hrs (p = .002) and 24 hrs (p v .026) after cecal ligation and perforation, and correlated with expression of heat shock proteins in the lungs. However, at 48 and 96 hrs, when heat shock protein expression returned to basal values, the mortality rates of both groups were indistinguishable. CONCLUSIONS: We conclude that in vivo injection of sodium arsenite induces expression of HSP-72 in the lungs, and confers transient protection against experimental sepsis during the period that heat shock proteins are also expressed.

Induction of the heat shock response reduces mortality rate and organ damage in a sepsis-induced acute lung injury model.

OBJECTIVE: To test the hypothesis that induction of heat shock proteins before the onset of sepsis could prevent or reduce organ injury and death in a rat model of intra-abdominal sepsis and sepsis-induced acute lung injury produced by cecal ligation and perforation. DESIGN: Prospective, blind, randomized, controlled trial. SETTING: University research laboratory. SUBJECTS: One-hundred forty-two adult Sprague-Dawley rats (weight range 200 to 300 g). INTERVENTIONS: Production of intra-abdominal sepsis and exposure to heat stress. Animals were randomly divided into four groups: heated and septic, heated and sham-septic, unheated and septic, and unheated and sham-septic. MEASUREMENTS AND MAIN RESULTS: We evaluated the mortality rate and pathologic changes in lung, heart, and liver at 18 hrs after cecal perforation, at 24 hrs after removal of the cecum, and at 7 days after perforation. Heated animals exhibited a maximum increase in heat shock protein of 72 kilodalton molecular weight protein concentrations in the lungs and heart 6 to 24 hrs after the hyperthermic stress. By 18 hrs after perforation, 25% of the septic, unheated animals had died whereas none of the septic heated animals had died (p < .005). Septic, heated animals showed a marked decrease in 7-day mortality rate (21%) compared with septic unheated animals (69%) (p < .01). Furthermore, septic heated animals showed less histologic evidence of lung and liver damage than septic unheated animals. CONCLUSIONS: These data suggest that thermal pretreatment, associated with the synthesis of heat shock proteins, reduces organ damage and enhances animal survival in experimental sepsis-induced acute lung injury. Although the mechanisms by which heat shock proteins exert a protective effect are not well understood, these data raise interesting questions regarding the importance of fever in the protection of the whole organism during bacterial infection.