The heat shock response in Polistes spp. brood from differing climates following heat stress.

Temperature is a crucial factor in many physiological processes, especially in small ectotherms whose body temperature is highly influenced by ambient temperature. Polistes (paper wasps) is a genus of primitively eusocial wasps found in widely varying thermal environments throughout the world. Paper wasps construct open-faced combs in which the brood is exposed to varying ambient temperatures. The Heat Shock Response is a physiological mechanism that has been shown to help cope with thermal stress. We investigated the expression of heat shock proteins in different life stages of three species of Polistes from different climates with the aim of deducing adaptive patterns. This was done by assaying heat shock protein (hsp70, hsp83, hsc70) expression during control conditions (25 °C) or a heat insult (35 or 45 °C) in individuals collected from natural populations in Alpine, Temperate, or Mediterranean climates. Basal expression of hsc70 and hsp83 was found to be high, while hsp70 and hsp83 expression was found to be highly responsive to severe heat stress. As expression levels varied based on species, geographical origin, and life stage as well as between heat shock proteins, the Heat Shock Response of Polistes was found to be complex. The results suggest that adaptive utilization of the heat shock response contributes to the ability of Polistes spp. to inhabit widely different thermal environments.

Differential expression of the adult specifier E93 in the strepsipteran Xenos vesparum Rossi suggests a role in female neoteny.

Holometaboly is a key evolutionary innovation that has facilitated the spectacular radiation of insects. Despite the undeniable advantage of complete metamorphosis, the female of some holometabolous species have lost the typical holometabolous development through neoteny. In Xenos vesparum Rossi (Strepsiptera: Stylopidae), a derived species of the holometabolous endoparasitic order Strepsiptera, neotenic females reach sexual maturity without the pupal and the imaginal stages, thus retaining their larval morphology (with the exception of the anterior part of the body or cephalothorax), while males undergo normal pupal-based metamorphosis. Expression of the "adult-specifier" E93 factor has been shown to be required for proper metamorphosis in holometabolous insects. Here, we investigated the involvement of E93 in female neoteny by cloning XvE93. Interestingly, while we detected a clear up-regulation of XvE93 expression in pupal and adult stages of males, persistent low levels of XvE93 were detected in X. vesparum females. However, a specific up-regulation of XvE93 was observed in the cephalothorax of late 4th female instar larva, which correlates with the occurrence of neotenic-specific features in the anterior part of the female body. Moreover, the same expression dynamic in the cephalothorax and abdomen was also observed for other two critical metamorphic regulators, the anti-metamorphic XvKr-h1 and the pupal specifier XvBr-C. The specific up-regulation of XvE93 and XvBr-C in the female cephalothorax seems to be the result of an increase in 20-hydroxyecdysone (20E) signaling in this region for we detected higher expression levels of the 20E-dependent nuclear receptors XvHR3 and XvE75 in the cephalothorax. Overall, our results detect a sex-specific expression pattern of critical metamorphic genes in X. vesparum, suggesting that neoteny in Strepsiptera results from the modification of the normal expression of E93, Br-C and Kr-h1 genes.

Effect of food quality on the body temperature of wasps (Paravespula vulgaris).

Body surface temperature of individually marked wasps (Paravespula vulgaris, Vespidae, Hymenoptera) was measured by infrared thermography during repeated visits to a feeding bowl without injuring them or disturbing their behavior. Wasps were fed 0.5, 1 and 2 mol/l sucrose solution at two ambient temperatures.Thoracic temperature varied significantly in dependence on food quality (sucrose concentration of solution). At the higher ambient temperatures of 26.1-30.2 degrees C mean thoracic surface temperatures from different experiments were 35.3 and 38.0 degrees C when the wasps took a 0.5 mol/l sucrose solution, 37.0, 38.7 and 38.7 degrees C when they took a 1 mol/l solution, and 39.1 degrees C when they took a 2 mol/l sucrose solution. At the lower ambient temperatures of 17.6-21.0 degrees C thoracic temperatures were lower but the effect of different sucrose concentrations was similar: 34.7 degrees C with a 0.5 mol/l and 36.1 degrees C with a 1 mol/l sucrose solution. The concentration effect amounted to about 10-25% of the whole variability of thorax temperature. By contrast, the temperatures of the head and abdomen did not follow the changes in thorax temperature according to changes in sucrose concentration closely, which suggests that the pattern of haemolymph circulation may have changed after landing, during the wasps' stay at the feeder. At initial landing at the feeders thoracic temperatures where equal to (three of eight tests) or lower (five of eight tests) than at final departure.The correlation of thorax temperature with food quality probably reflects the wasps' level of excitement and motivation to collect the food, which allows them to balance energetic investment with profitability of foraging and the needs of flight muscle performance and motility.

Treatment of cerebral radionecrosis by hyperbaric oxygen therapy.

Clinically observed adverse radiation effects (ARE) are rather uncommon, but modern imaging reveals that they are more common after radiosurgery than previously believed. Little is known about the pathogenesis, and current treatment is mostly empirical. The benefit of hyperbaric oxygen therapy (HBO) on radiation-induced bone and soft tissue necrosis is known in lesions in the maxillofacial area, the mouth and in the head and neck. HBO raises the tissue pO2 and initiates a cellular and vascular repair mechanism. This forms the basis for the hypothesis that it might also help alleviate the results of cerebral radionecrosis. This study is a preliminary attempt to test this hypothesis. Two patients with arteriovenous malformations (AVMs) were chosen for the study. They had been treated with Gamma Knife radiosurgery (GKRS) and had developed imaging signs consistent with ARE. They were treated by breathing 100% oxygen at 2.5 atmospheres absolute (250 kPa) in sessions of 60 minutes per day. This treatment was repeated 40 times in cycles of ten sessions. Both responded well to HBO, one lesion disappeared and the other was reduced significantly in size. No adjuvant steroids were given. These results give evidence that HBO has a potential value in treating ARE but further experience will be needed to confirm its definite benefit.

Quantification of the dermal vascular response to hyperbaric oxygen with laser-Doppler flowmetry.

The vasoconstrictive response to hyperbaric oxygen (HBO2) therapy was non-invasively quantified in eight healthy volunteers at 1.95 and 2.5 atm abs (197.5 and 253.2 kPa; multiplace chamber, air environment) by laser-Doppler flowmetry (LDF). The sensors for continuous measurement of microvascular perfusion (flux) and skin temperature were localized on the thenar eminence. Transcutaneous oxygen (tcPO2) and carbon dioxide (tcPCO2) tensions, blood pressure, heart rate, respiration rate, peripheral oxygen saturation, and temperature of the hyperbaric chamber were recorded at five conditions: 1) baseline--air breathing at 1.0 atm abs, 2) after 15 min of HBO2 at 2.5 atm abs, 3) after 15 min of HBO2 at 1.95 atm abs, 4) 1 min after decompression with oxygen breathing at 1.0 atm abs, and 5) after 15 min of breathing air at 1.0 atm abs. Flux decreased continuously at conditions 2 (76.5%), 3 (50.6%), and 4 (37% of baseline, P < 0.05; Tukey test). Skin temperature fell below baseline at conditions 2, 3, 4 (P < 0.01, Tukey test), and 5 (P < 0.05, Tukey test, P < 0.001, analysis of variance). Range of correlation between inspired gas PO2 (PIO2) and alteration of flux 0.91 to 0.72, median -0.41. Correlation between PIO2 and tcPO2, r = 0.98. Chamber temperature and tcPCO2 remained stable. HBO2 reduced dermal microcirculation and temperature disproportionate to PIO2. LDF is suitable for use under hyperbaric conditions.

Transcranial cerebral oximetry in the hyperbaric environment.

Continuous monitoring of dynamic changes of transcranial regional cerebral oxygenation (rSO2) was performed in 7 healthy volunteers (mean age 40.9 +/- 12.6 years; range 25-62 years) during normo- and hyperbaric oxygenation (HBO at 2.5 and at 1.95 ATA) using an INVOS 3100 cerebral oximeter. A significant change between HBO and control phase could be found in rSO2, alterations (p < 0.05; ANOVA, Tukey test). The results suggest that the calculation of rSO2 may be a useful method to monitor changes of oxygen saturation under hyperbaric conditions. However, the absolute quantification of rSO2 is useless at the moment and needs further investigation.

Laser doppler flowmetry in the hyperbaric environment.

Continuous monitoring of laser Doppler (LD) flowmetry was performed in eight healthy volunteers (mean age 42.0 + 12.1 yr; range 25-62 yr) before, during and after hyperbaric oxygenation ([HBO at 2.5 and 1.95 ATA (atmosphere absolute)]).Two models of the discrimination analysis are presented which allow classification, resulting from the parameter obtained by the LD flowmetry.The results show that 100% separation of the LD data under HBO at 2.5 and 1.95 ATA including five parameters can be achieved with the first model. The second model for the analysis of four different phases with eight parameters still shows an obvious separation; however, only 75% of the group integration is correct. In addition to transcutaneous P(2) measurements, which are sometimes difficult to obtain perfectly, LD parameters will be of interest to manage HBO treatment, especially when peripheral circulation is reduced.

[Hyperbaric surgery and oxygen therapy in clostridial myonecrosis]. / Hyperbare Chirurgie und Sauerstofftherapie der clostridialen Myonekrose.

116 patients with verified clostridial myonecrosis were treated by means of a regimen of combined cyclic hyperbaric oxygenation at 3 ata and repeated necrectomy. With proximal localization of gas gangrene in the elbow or knee (n = 55) 34.5% of patients survived, whilst with peripheral localization at the limbs (n = 44) the survival rate was 88.6% amputation being avoided in 21 of these cases. Abdominal localization (n = 17) was associated with the lowest survival rate (23.5%). In spite of severe clostridial toxicity in 80.1% of patients at the time of admission, the overall mortality was 50.8%.

Endothelial cells in the oral mucosa of Bufo marinus.

The oral mucosa of the cane toad (Bufo marinus) is lined by a pseudostratified columnar ciliated epithelium containing an intraepithelial network of capillaries, which penetrates it to the bases of the distal layer of cells. The capillaries are lined by fenestrated endothelium lying on a complete basal lamina. A connective tissue sheath, approximately 1 micrometer thick, surrounds the capillaries and separates them from the surrounding epithelial cells. Endothelial cells resemble those in lymphatic capillaries in that they show microvillus-like processes or folds projecting into the lumen and also have extremely attenuated and fenestrated cytoplasm except in the nuclear region. Numerous pinocytotic vesicles, bundles of filaments and many electrondense granules occur in the cytoplasm. These granules are oval or round in shape and approximately 250-400 micrometer in diameter. Histochemical tests on the endothelial cells show that the granules do not contain pigment, as both the Schmorl and argentaffin reactions are negative. Both the Sudan black B and Luxol fast blue reactions are also negative showing the lack of stainable lipids. The formaldehyde-induced fluorescence, the argentaffin reactions and lead haematoxylin reactions are negative, indicating that they do not have the characteristics of endocrine cells. The acid phosphatase reaction gives a positive result, localized to the site of the granules by electron microscopy and suggesting that these granules in amphibian capillaries may have a lysosomal function.