Responses of two Anastrepha species' immature stages infesting preferential hosts to different temperature exposures.

Anastrepha fraterculus (Wiedemann) and A. obliqua (Macquart) are important pests of fruit crops. In Brazil, these species cause damage to fruit growing in the South (annual average temperature of 20.9 °C) and Northeast (average yearly temperature of 24 °C). We evaluated the effect of temperature on the viability and development time of A. fraterculus and A. obliqua immature stages in their respective preferred hosts, guava (Psidium guajava L., Myrtaceae) and mango (Mangifera indica L., Anacardiaceae). The duration of egg and pupal stages, egg to pre-pupa, and viability of egg and pupal stages under different temperatures (15, 20, 25, 30, and 35 °C) were assessed. For both species, development time decreased with increasing temperature. Viability in the evaluated stages was only observed between 15 and 30 °C. However, the species responded differently to the exposure temperatures (15 and 30 °C), especially in the pupal stage and from egg to pre-pupa. Anastrepha fraterculus showed a lower tolerance to high temperatures, especially in the pupal stage and from egg to pre-pupa, which may explain its lower importance and economic impact in warmer Brazilian regions. Anastrepha obliqua had a lower tolerance at 15 °C, indicating greater adequacy for temperatures above 20 °C, characteristic of Northeast Brazil, suggesting the capacity to spread to cooler areas with rising temperatures.

Effect of brief exposures of anesthesia on thermotolerance and metabolic rate of the spotted-wing fly, Drosophila suzukii: Differences between sexes?

The spotted-wing fly, Drosophila suzukii, is a world-wide pest insect for which there is increasing interest in its physiological traits including metabolism and thermotolerance. Most studies focus only on survival to different time exposures to extreme temperatures, mainly in female flies. In addition, it has not been tested yet how anesthesia affects these measurements. We analyzed the effects of anesthesia by brief exposures to cold, anoxia by CO2 or N2 on three standard thermotolerance assays, as well as the aerobic metabolic rate in both sexes. For heat tolerance we measured CTmax by thermolimit respirometry, and CTmin and chill-coma recovery time for cold tolerance. Aerobic metabolism was calculated by CO2 production of individual flies in real time by open flow respirometry. Results showed that females have a significantly higher V̇CO2 for inactive (at 25 °C) and maximum metabolic rate than males. This difference is mainly explained by body mass and disappears after mass correction. Males had a more sensitive MR to temperature than females showed by a significantly higher Q10 (2.19 vs. 1.98, for males and females, respectively). We observed a significantly lower CTmin (X2 = 4.27, P = 0.03) in females (3.68 ± 0.38 °C) than males (4.56 ± 0.39 °C), although we did not find significant effects of anesthesia. In contrast, anesthesia significantly modifies CTmax for both sexes (F3,62 = 7.86, P < 0.001) with a decrease of the CTmax in cold-anesthetized flies. Finally, we found a significantly higher CTmax in females (37.87 ± 0.07 °C) than males (37.36 ± 0.09 °C). We conclude that cold anesthesia seems to have detrimental effects on heat tolerance, and females have broader thermotolerance range than males, which could help them to establish in invaded temperate regions with more variable environmental temperatures.

Thermophysiological plasticity could buffer the effects of global warming on a Patagonian lizard.

Ecophysiological plasticity determines, to a great extent, the geographic distribution and the vulnerability of ectotherms to climate change. We studied the relationship between locomotor performance and temperature of Liolaemus elongatus lizards in three populations in northern Patagonia, Argentina, differing in thermal characteristics. We related the thermophysiological and locomotor performance parameters with the environmental conditions currently experienced by these populations and analyzed whether the expected increment of the environmental temperature due to climate change could affect these vital traits. We also determined, for one of the populations, the effects of 30 acclimation days at two temperature treatments (22°C and 30°C) on running speed, thermal preference in the laboratory (Tpref ), panting threshold, and minimum critical temperature. We found that L. elongatus, despite the differences in environmental temperatures among the three sites, exhibited maximum speed at similar temperatures (optimum temperature for locomotor performance; To ). The southern populations currently experience temperatures below that required to reach their maximum locomotor performance while the northernmost population is threatened by peaks of high temperatures that exceed the To . Therefore, global warming could diminish lizards' running performance in northern populations and lizards may spend more time refuging and less time on other activities such as feeding, territory defense, and dispersion. However, we show evidence of plasticity in L. elongatus locomotor performance when acclimated at high temperatures resulting in a potential advantage to cushion the effect of the rising environmental temperatures expected during climate change.

Latitudinal pattern of the thermal sensitivity of running speed in the endemic lizard Liolaemus multimaculatus.

Physiological performance in lizards may be affected by climate across latitudinal or altitudinal gradients. In the coastal dune barriers in central-eastern Argentina, the annual maximum environmental temperature decreases up to 2°C from low to high latitudes, while the mean relative humidity of the air decreases from 50% to 25%. Liolaemus multimaculatus, a lizard in the family Liolaemidae, is restricted to these coastal dunes. We investigated the locomotor performance of the species at 6 different sites distributed throughout its range in these dune barriers. We inquired whether locomotor performance metrics were sensitive to the thermal regime attributable to latitude. The thermal performance breadth increased from 7% to 82% with latitude, due to a decrease in its critical thermal minimum of up to 5°C at higher latitudes. Lizards from high latitude sites showed a thermal optimum, that is, the body temperature at which maximum speed is achieved, up to 4°C lower than that of lizards from the low latitude. At relatively low temperatures, the maximum running speed of high-latitude individuals was faster than that of low-latitude ones. Thermal parameters of locomotor performance were labile, decreasing as a function of latitude. These results show populations of L. multimaculatus adjust thermal physiology to cope with local climatic variations. This suggests that thermal sensitivity responds to the magnitude of latitudinal fluctuations in environmental temperature.

Superficial temperature and pain tolerance in patients with chronic low back pain.

INTRODUCTION: Low back pain is a common and very prevalent disease and can impose limitations that negatively impact patients. The objective of this study was to verify and compare the association between lumbar superficial temperature and pressure pain tolerance thresholds in individuals with chronic nonspecific low back pain and healthy controls. METHODS: This was a cross-sectional observational study involving 38 individuals with nonspecific chronic low back pain and 19 healthy controls. Volunteers underwent thermographic (infrared sensor), pain perception (visual analog scale), and pressure pain tolerance thresholds (algometry) evaluations in the right and left paravertebral muscles and L4-L5 ligament. RESULTS: A lower tolerance to pressure pain was found in patients compared to controls at all evaluated sites (p ≤ 0.003). Superficial temperature was significantly higher in the sites evaluated in the low back pain group (p < 0.001). In patients with low back pain, pain perception was weakly and inversely correlated with pressure pain tolerance (r = -0.31; p = 0.05) and moderately correlated to the temperature of the evaluated sites (r = 0.51 to 0.59, p ≤ 0.001). Also, an inverse and weak to moderate association was observed between pressure pain tolerance thresholds and temperature in patients only (r = -0.36 to -0.49; p ≤ 0.02). CONCLUSION: Individuals with low back pain have lower pressure pain tolerance thresholds and higher superficial temperature in the lumbar region when compared to healthy individuals. The associations observed show that the higher the pain perception, the lower the pain tolerance and the higher the superficial temperature in the lumbar region. Also, the higher the temperature, the lower the pain tolerance.

Fifty Years of Mountain Passes: A Perspective on Dan Janzen's Classic Article.

In 1967, Dan Janzen published "Why Mountain Passes Are Higher in the Tropics" in The American Naturalist. Janzen's seminal article has captured the attention of generations of biologists and continues to inspire theoretical and empirical work. The underlying assumptions and derived predictions are broadly synthetic and widely applicable. Consequently, Janzen's "seasonality hypothesis" has proven relevant to physiology, climate change, ecology, and evolution. To celebrate the fiftieth anniversary of this highly influential article, we highlight the past, present, and future of this work and include a unique historical perspective from Janzen himself.

Evaluation of body temperature in individuals with stroke.

BACKGROUND: A stroke can cause alterations in thermal sensitivity. OBJECTIVE: to verify the conditions of body temperature in hemiplegic patients after stroke as compared to healthy individuals, as well as establish relations between thermal sensitivity and gender, age, Body Mass Index (BMI), plegic side, time after stroke, reports of thermal alterations and the motricity of patients with stroke sequelae. METHODS: This cross-sectional study included 100 patients (55.6±13 years) with ischemic or hemorrhagic stroke sequelae with unilateral hemiparesis and thirty healthy subjects (55±12.9 years). Individuals with nervous peripheral lesions, diabetes, peripheral vascular diseases or tumors were not included in this study. The volunteers underwent axillary temperature evaluations with the use of a cutaneous thermometer and evaluations of cutaneous temperature of hands and feet as measured by infrared thermography captured by an infrared sensor (ThermaCAMTM SC 500-FLIR Systems). The mean temperature (°C) was analyzed with the SigmaStat 3.5 statistical package. RESULTS: The results have shown that healthy individuals have similar temperatures on either side of the body. The hemiplegic subjects presented a lower temperature on the plegic side and compared to the healthy subjects, both feet of the hemiparetic individuals were colder. The results have also shown that age, body mass index, and the time after stroke have no influence on the alterations in temperature. Regarding the paretic side, individuals with hemiplegia on the right side (right foot) had a lower temperature than those affected on the left side. Motricity was not related to any difference in temperature between the limbs and the reports of temperature differences had no relation with the actual differences found in the study. CONCLUSIONS: Healthy individuals have temperature symmetry between between sides of the body, while individuals with stroke sequelae present lower temperature in the paretic side, especially on their feet.

Microhabitat and body size effects on heat tolerance: implications for responses to climate change (army ants: Formicidae, Ecitoninae).

1. Models that predict organismal and population responses to climate change may be improved by considering ecological factors that affect species thermal tolerance. Species differences in microhabitat use can expose animals to diverse thermal selective environments at a given site and may cause sympatric species to evolve different thermal tolerances. 2. We tested the hypothesis that species differences in body size and microhabitat use (above- vs. below-ground activity) would correspond to differences in thermal tolerance (maximum critical temperatures: CTmax ). Thermal buffering effects of soil can reduce exposure to extreme high temperatures for below-ground active species. We predicted larger-bodied individuals and species would have higher CTmax and that species mean CTmax would covary positively with degree of above-ground activity. We used Neotropical army ants (Formicidae: Ecitoninae) as models. Army ants vary in microhabitat use from largely subterranean to largely above-ground active species and are highly size polymorphic. 3. We collected data on above- and below-ground temperatures in habitats used by army ants to test for microhabitat temperature differences, and we conducted CTmax assays for army ant species with varying degrees of surface activity and with different body sizes within and between species. We then tested whether microhabitat use was associated with species differences in CTmax and whether microhabitat was a better predictor of CTmax than body size for species that overlapped in size. 4. Microhabitat use was a highly significant predictor of species' upper thermal tolerance limits, both for raw data and after accounting for the effects of phylogeny. Below-ground species were more thermally sensitive, with lower maximum critical temperatures (CTmax ). The smallest workers within each species were the least heat tolerant, but the magnitude of CTmax change with body size was greater in below-ground species. Species-typical microhabitat was a stronger predictor of CTmax than body size for species that overlapped in size. Compared to the soil surface, 10-cm subsoil was a significantly moderated thermal environment for below-ground army ants, while maximum surface raid temperatures sometimes exceeded CTmax for the most thermally sensitive army ant castes. 5. We conclude sympatric species differences in thermal physiology correspond to microhabitat use. These patterns should be accounted for in models of species and community responses to thermal variation and climate change.

Sensibilidade térmica em ratas submetidas à natação / Thermal sensitivity in rats submitted to swimming

The swimming has a number of physiological benefits, among which we can mention the increased resistance to the perception of thermal stimuli. The thermal sensitivity is designated as responsive to rising temperature, harmful heat, decrease the temperature and harmful cold. The thermal and painful sensations are transmitted to the central nervous system via axons C, Aδ. The heat-sensitive fibers C are called mecanotermossensíveis C fibers, which require different membrane receptors to make the distinction between various sensory thresholds. These receptors are called channels TRP (transient receptor potential) and are responsible for performing the transduction of thermal signals. The termocepção can be measured by the hot plate test based on the response latency to a given adverse thermal stimulus. Objectives: to determine the thermal sensitivity in rats submitted to swimming. Methods: This study was approved by the Ethics Committee for the Use of Animals (CEUA) of the State University of Ceará (UECE), Official Letter No. 12725887-0. 16 female Wistar rats were used ± 8 weeks, divided into two groups: control (C) and swimming (N). The animals swimming starting time duration of 3 minutes for the first week and reaching 36 minutes at the end of the second week with a 5% body weight load tied to the tail, to avoid floating. The exercises in the water were carried out by the morning shift, six days a week and a weekly rest. The animals were then immediately dried by a hot air jet device (sized hair dryer). Thermal sensitivity was evaluated using the hot plate test at 50°C is considered as a valid positive response and the heel of the animal licks its hind legs and cleaning of the animals forepaws. The results were analyzed by comparing an average between the two groups tested by one-way ANOVA analysis. Statistical analysis was performed using t test for independent samples, assuming significance of p <0.05. Results and Discussion: As a result, one can observe a significant increase (p = 0.014) in response time to thermal stimulation of the swimming group (5.875 ± 1.060 N = 8) compared to the control group (2.375 ± 0.962 N = 8). These results confirm previous studies, which show that swimming is able to increase the nociceptive threshold in rodents, suggesting that exercise the aquatic environment is able to reduce the activation of TRPV1 channels, which are only activated at temperatures between 42 and 52 ° C. This mechanism might explain the increased latency response comparing the swimming group with the control group. Conclusion: The data demonstrate that swimming increased tolerance to thermal stimuli, which produces a positive effect on the animals, it increases the selectivity of the intensity of painful stimuli perceived by the body.(AU)

Sensibilidade térmica em ratas submetidas à natação / Thermal sensitivity in rats submitted to swimming

The swimming has a number of physiological benefits, among which we can mention the increased resistance to the perception of thermal stimuli. The thermal sensitivity is designated as responsive to rising temperature, harmful heat, decrease the temperature and harmful cold. The thermal and painful sensations are transmitted to the central nervous system via axons C, Aδ. The heat-sensitive fibers C are called mecanotermossensíveis C fibers, which require different membrane receptors to make the distinction between various sensory thresholds. These receptors are called channels TRP (transient receptor potential) and are responsible for performing the transduction of thermal signals. The termocepção can be measured by the hot plate test based on the response latency to a given adverse thermal stimulus. Objectives: to determine the thermal sensitivity in rats submitted to swimming. Methods: This study was approved by the Ethics Committee for the Use of Animals (CEUA) of the State University of Ceará (UECE), Official Letter No. 12725887-0. 16 female Wistar rats were used ± 8 weeks, divided into two groups: control (C) and swimming (N). The animals swimming starting time duration of 3 minutes for the first week and reaching 36 minutes at the end of the second week with a 5% body weight load tied to the tail, to avoid floating. The exercises in the water were carried out by the morning shift, six days a week and a weekly rest. The animals were then immediately dried by a hot air jet device (sized hair dryer). Thermal sensitivity was evaluated using the hot plate test at 50°C is considered as a valid positive response and the heel of the animal licks its hind legs and cleaning of the animals forepaws. The results were analyzed by comparing an average between the two groups tested by one-way ANOVA analysis. Statistical analysis was performed using t test for independent samples, assuming significance of p <0.05. Results and Discussion: As a result, one can observe a significant increase (p = 0.014) in response time to thermal stimulation of the swimming group (5.875 ± 1.060 N = 8) compared to the control group (2.375 ± 0.962 N = 8). These results confirm previous studies, which show that swimming is able to increase the nociceptive threshold in rodents, suggesting that exercise the aquatic environment is able to reduce the activation of TRPV1 channels, which are only activated at temperatures between 42 and 52 ° C. This mechanism might explain the increased latency response comparing the swimming group with the control group. Conclusion: The data demonstrate that swimming increased tolerance to thermal stimuli, which produces a positive effect on the animals, it increases the selectivity of the intensity of painful stimuli perceived by the body.

Diretrizes para avaliação somatossensorial em pacientes portadores de disfunção temporomandibular e dor orofacial / Guidelines for somatosensory evaluation of temporomandibular dysfunction and orofacial pain patients

JUSTIFICATIVA E OBJETIVOS: Diferentes estímulos são necessários para avaliar a integridade das fibras aferentes e compreender melhor os mecanismos envolvidos nas diferentes condições dolorosas que podem afetar a região orofacial. O principal objetivo deste estudofoi realizar uma revisão da literatura, proporcionando diretrizes para a prática clínica.CONTEÚDO: Foram realizadas buscas na literatura de 1990 a 2011, na base de dados PubMed utilizando-se termos MeSH. A estimulação mecânica pôde ser realizada mediante o uso de monofilamentos de Von-Frey, para testar as fibras A-beta e A-delta. O teste de picada é uma maneira simples de se avaliar as fibrasA-delta e C. O limiar de dor à pressão (LDP) testa as fibras A-delta e C. Dentre as modalidades de ensaios térmicos, pode-se utilizar cubos de gelo ou um spray aerosol congelante para medir a nível de sensibilização central envolvido. Os estímulos elétricos, aplicados pelo aparelho Neurometer/Neurotron®, avaliam os três tipos principais de fibras (A-delta, A-beta e C), hiperestesia e hipoestesia. Além disso, as fibras do tipo C também podem ser avaliadas por estímulos químicos com capsaicina e/ou mentol. CONCLUSÃO: Os testes quantitativos sensoriais consistem em uma forma confiável para avaliação da função sensorial das fibras nervosas. O déficit sensorial pode ser quantificado e os dados utilizados como auxílio diagnóstico ou para comparações de eficácia entre diferentes modalidades de tratamento.

BACKGROUND AND OBJECTIVES: Different stimulations are needed to evaluate the integrity of afferent fibers and to better understand the mechanisms involved in different pain conditions which may affec tthe orofacial region. This study aimed primarily at reviewing the literature to provide guidelines to the clinical practice.CONTENTS: PubMed database was searched from 1990 to 2011 using MeSH terms. Mechanical stimulation could be done with Von-Frey monofilaments to testA-beta and A-delta fibers. Pinprick test is a simple way to evaluate A-delta and C fibers. Pressure pain threshold (PPT) tests A-delta and C fibers. Among thermal test modalities one may use ice cubes or a freezing spray to measure the level of central sensitization involved. Electric stimulations applied by the Neurometer/Neurotron® device evaluated three major fibers (A-delta, A-beta and C), hyperesthesia and hypoesthesia. In addition, C fibers can also be evaluated by chemical stimulations with capsain and/or menthol.CONCLUSION: Quantitative sensory tests are a reliable way to evaluate nervous fibers sensory function.Sensory deficit may be quantified and data may be used as diagnostic aid or to compare the effectiveness of differentt reatment modalities.