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The vapor pressure differences between a mixture of (CH4+CD4) and CH4 and between CD4 and CH4 were measured simultaneously with the CH4 vapor pressure. This was done at 29 temperatures between 97 and 122 K, and for six different mixtures, of compositions 0.150, 0.250, 0.375, 0.500, 0.625, and 0.750 mole fraction in CD4. These mixtures exhibit very small positive deviations from Raoult’s law. Calculated excess Gibbs energies for equimolar mixtures were 0.60 J mol-1 at 100 K and 0.42 J mol-1 at 120 K. These values of GE are 2 to 3 orders of magnitude smaller than those typically found in binary mixtures of simple nonisotopic species. The molar excess enthalpy, calculated from the temperature dependence of GE, is HE(x=0.5)=(1.5±0.2) J mol-1. The experimental results were used to test three theoretical models: the vdW-1 fluid theory, 1cLJ perturbation theory, and the theory of isotope effects in mixtures. While the first two proved to be inadequate, the isotope effect theory agrees well with experiment. [ABSTRACT FROM AUTHOR]

Revascularization after long term aortic ischaemia in vascular surgery induces reperfusion injury accompanied with oxidative stress and inflammatory responses. The hypothesis of this study was that the aortic occlusion followed by controlled reperfusion (CR) can reduce the ischaemia-reperfusion injury, the systemic and local inflammatory response induced by oxidative stress. Animal model was used. Control group: animals underwent a 4-hour infrarenal aortic occlusion followed by continuous reperfusion. Treated group: animals were treated with CR: after a 4-hour infrarenal aortic occlusion we made CR for 30 minutes with the crystalloid reperfusion solution (blood: crystalloid solution ratio 1:1) on pressure 60 Hgmm. Blood samples were collected different times. The developing oxidative stresswas detected by the plasma levels of malondialdehyde, reduced glutathion, thiol groups and superoxide dismutase. The inflammatory response was measured by phorbol myristate acetateinduced leukocyte reactive oxygen species production and detection of change in myeloperoxidase levels. The animals were anaesthetized one week after terminating ligation and biopsy was taken from quadriceps muscle and large parenchymal organs. CR significantly reduced the postischaemic oxydative stress and inflammatory responses in early reperfusion period. Pathophysiological results: The rate of affected muscle fibers by degeneration was significantly higher in the untreated animal group. The infiltration of leukocytes in muscle and parenchymal tissues was significantly lower in the treated group. CR can improve outcome after acute lower-limb ischaemia. The results confirm that CR might be also a potential therapeutic approach in vascular surgery against reperfusion injury in acute limb ischaemia. Supported by OTKA K108596. [ABSTRACT FROM AUTHOR]

The distribution of spinal primary afferent terminals labeled transganglionically with the choleratoxin B subunit (CTB) or its conjugates changes profoundly after perineural treatment with capsaicin. Injection of CTB conjugated with horseradish peroxidase (HRP) into an intact nerve labels somatotopically related areas in the ipsilateral dorsal horn with the exceptions of the marginal zone and the substantia gelatinosa, whereas injection of this tracer into a capsaicin-pretreated nerve also results in massive labeling of these most superficial layers of the dorsal horn. The present study was initiated to clarify the role of C-fiber primary afferent neurons in this phenomenon. In L5 dorsal root ganglia, analysis of the size frequency distribution of neurons labeled after injection of CTB-HRP into the ipsilateral sciatic nerve treated previously with capsaicin or resiniferatoxin revealed a significant increase in the proportion of small neurons. In the spinal dorsal horn, capsaicin or resiniferatoxin pretreatment resulted in intense CTB-HRP labeling of the marginal zone and the substantia gelatinosa. Electron microscopic histochemistry disclosed a dramatic, ∼10-fold increase in the proportion of CTB-HRP-labeled unmyelinated dorsal root axons following perineural capsaicin or resiniferatoxin. The present results indicate that CTB-HRP labeling of C-fiber dorsal root ganglion neurons and their central terminals after perineural treatment with vanilloid compounds may be explained by their phenotypic switch rather than a sprouting response of thick myelinated spinal afferents which, in an intact nerve, can be labeled selectively with CTB-HRP. The findings also suggest a role for GM1 ganglioside in the modulation of nociceptor function and pain. [ABSTRACT FROM AUTHOR]

After revascularization of an acute arterial occlusion the development of a serious ischaemic-reperfusion injury is a menacing challenge and a hard task in peripheral vascular surgery. A whale of evidences point to oxidative stress, as an important trigger, in the complex chain of events leading to reperfusion injury. In the present study authors aimed to examine oxidative stress parameters, antioxidant–prooxidant state and leukocyte adhesion molecules (CD11a and CD18) expression following acute revascularization surgery of lower limb. 10 patients were examined in the prospective randomized study. Peripheral blood sample was collected in ischaemic period, and after reperfusion in the 2nd and 24th hours, and on 7th day. Superoxide-dismutase activity, reduced glutathion concentration and leukocytes free radical production were measured. The degree of lipidperoxidation was marked with the quantity of malondialdehyde. The expressions of adhesion molecules were measured with flowcytometry. The speed and rate of free radical production significantly increased in the early reperfusion (p<0.05). The level of antioxidant enzymes decreased after revascularization. The CD11a and CD18 expression of the granulocytes significantly (p<0.05) decreased right after the revascularization, but with a gradual elevation until the 7th day they exceed the ischaemic value. Our results showed a time specific turnover of the sensitive antioxidant–prooxidant balance after revascularization operation. [ABSTRACT FROM AUTHOR]

The closed-loop phase diagram of 3-methylpyridine—heavy water mixture was studied, to our best knowledge, for the first time with dynamic neutron radiography (DNR) at the 10 MW VVR-SM Research Reactor in Budapest (Hungary). Visualized were the (i) lower temperature non-segregated states (below 38°C), (ii) transition (40–43°C), (iii) segregated states (46–128°C), (iv) higher temperature transition (110–128°C) and (v) higher temperature non-segregated states. The non-segregated state belonging to 141°C, was found to be definitely dissimilar from the lower temperature state. Existence of a solid-like structure at the liquid–liquid interface was indicated. [Copyright &y& Elsevier]

It has been demonstrated on model systems that no difference between the radial distribution functions of molecules in isotopic mixtures can be observed by classical molecular dynamics simulations. In contrast, the Kirkwood–Buff integrals can yield information about the preferential solvation in these mixtures. The calculations of the Kirkwood–Buff integrals for the equimolar mixture of benzene and deuterobenzene have shown that in the case of positive excess Gibbs energy of the mixture, the isotopic molecules prefer to be surrounded by molecules of the same species. The extent of this preferential solvation is several orders of magnitude smaller than that observed in simple mixtures. [Copyright &y& Elsevier]

Pharmacological modulation of the transient receptor potential vanilloid-1 (TRPV1) receptor function offers a promising means of producing pain relief at the level of the primary sensory neuron. In this issue of the BJP, the pharmacological approaches and the available experimental data that focus on the TRPV1 receptor to achieve therapeutically useful alleviation of pain and inflammation are reviewed. The potentials to inactivate TRPV1 receptor function by site- and modality-specific TRPV1 antagonists, uncompetitive TRPV1 blockers and drugs interfering with TRPV1 sensitization, are evaluated. A crucial issue of producing pain relief at the level of the nocisensor remains whether it can be achieved solely through inactivation of the TRPV1 receptor or TRPV1 agonist-induced defunctionalization of the whole primary afferent neuron is required. The accumulated evidence indicates that both pharmacological modulation of the intracellular trafficking of the TRPV1 receptor and defunctionalization of the nocisensors by TRPV1 agonists are promising novel approaches to tame the TRPV1 receptor.British Journal of Pharmacology (2008) 155, 1139–1141; doi:10.1038/bjp.2008.375; published online 10 November 2008 [ABSTRACT FROM AUTHOR]

Small-angle neutron scattering (SANS) studies of 1-propanol-heavy water mixtures were performed in the mole fraction range of 0.02-0.6 at 20°C. Enhanced scattering was observed in the alcohol mole fraction range 0.1-0.3 revealing the enhanced aggregation of the alcohol molecules. From the experimental data the fluctuations and the Kirkwood-Buff integrals were calculated and compared with those obtained by small-angle X-ray scattering and from thermodynamic data. It was demonstrated that SANS is a suitable method to determine the Kirkwood-Buff integrals in liquid mixtures. [ABSTRACT FROM AUTHOR]

Background and Purpose: Sensory neuropathy develops in the presence of cardiovascular risk factors (e.g. diabetes, dyslipidemia), but its pathological consequences in the heart are unclear. We have previously shown that systemic sensory chemodenervation by capsaicin leads to impaired myocardial relaxation and diminished cardiac nitric oxide (NO) content. Here we examined the mechanism of diminished NO formation and if it may lead to a reduction of peroxynitrite (ONOO(-))-induced S-nitrosylation of sarcoendoplasmic reticulum Ca(2+)-ATPase (SERCA2a).Experimental Approach: Male Wistar rats were treated with capsaicin for 3 days to induce sensory chemodenervation. Seven days later, myocardial function and biochemical parameters were measured.Key Results: Capsaicin pretreatment significantly increased left ventricular end-diastolic pressure (LVEDP) decreased cardiac NO level, Ca(2+)-dependent NO synthase (NOS) activity, and NOS-3 mRNA. Myocardial superoxide content, xanthine oxidoreductase and NADPH oxidase activities did not change, although superoxide dismutase (SOD) activity increased. Myocardial and serum ONOO(-) concentration and S-nitrosylation of SERCA2a were significantly decreased.Conclusions and Implications: Our results show that sensory chemodenervation decreases cardiac NO via decreased expression and activity of Ca(2+)-dependent NOS and increases SOD activity, thereby leading to decreased basal ONOO(-) formation and reduction of S-nitrosylation of SERCA2a, which causes impaired myocardial relaxation characterized by increased left ventricular end-diastolic pressure (LVEDP). This suggests that capsaicin sensitive sensory neurons regulate myocardial relaxation via maintaining basal ONOO(-) formation and SERCA S-nitrosylation. [ABSTRACT FROM AUTHOR]

Abstract: Small-angle neutron scattering experiments and density measurements were carried out on dilute solutions of N,N′-dimethylethyleneurea (DMEU) in heavy water in the aquamolality ranges 0.28–2.92 and 0.28–4.17, respectively, at 298.15 and 313.15 K. The results obtained for DMEU, the cyclic analogue of tetramethylurea (TMU), were compared with those reported for TMU solutions in the literature. Whereas in the aqueous solution of TMU the hydrophobic interaction increases with increasing temperature, the second osmotic virial coefficient obtained from the concentration dependence of the forward scattering intensities in the DMEU solution is temperature independent. In contrast with the TMU solution, the radius of gyration in the DMEU solution appears to be constant below the aquamolality of about 2. The molal volume second virial coefficient (V xx ), calculated from the densities of the solutions, is negative, which indicates that DMEU has a structure-making effect on water. In the TMU solution the value of V xx was found to be more negative, which suggests that the water molecules are more structured in the hydration sphere of TMU than in that of DMEU molecule. The results of both the SANS and the volumetric studies on dilute solutions of DMEU lead to the conclusion that the pair-wise solute–solute interactions are weaker in DMEU than in TMU solutions. [Copyright &y& Elsevier]

In 3-methylpyridine--heavy water mixture, the segregation in the closed-loop phase diagram in relation to the temperature and heavy water concentration was studied by dynamic neutron radiography (DNR) at the 10 MW VVR-SM Research Reactor in Budapest, Hungary. On the pixel properties of the DNR images, taken from the phase separation process by Iman 2β v. image analyzing program, polynomial fitting, 3-D intensity histograms were applied. For modeling the segregation process, a two-variable segregation model: S = f(T, D) was set up. From the partial differentiation of the function f with respect to the temperature it was established that the highest rate changes in the segregation take place in the region of 50-55 °C and are modified by 3-methylpyridine concentration. The increase in the segregation process progresses up to 93-96°C, then declines. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Pneumoperitoneum, widely used in laparoscopic surgery increases the intraabdominal pressure, leading to hypoperfusion of the abdominal organs, and promoting the buildup of reactive oxygen species(ROS) and inflammatory cytokines which in turn impairs the body postoperatively. Aim of our investigation was to evaluate the potential protective effects of short ischemic episodes on ischemic damages. METHODS: 70 Wistar rats were used, divided into 7 groups: 1st group sham, 2nd group pneumoperitoneum with 5 mmHg, 3rd group preconditioning with 5 mmHg, 4th group: postconditioning with 5 mmHg, 5th group pneumoperitoneum with 10 mmHg, 6th group: preconditioning with 10 mmHg, 7th group postconditioning with 10 mmHg. Pneumoperitoneum was created by Veres needle. Oxidative stress parameters: malondialdehyde (MDA) concentration, reduced glutathione (GSH), sulfhydril (SH-), myeloperoxidase (MPO) levels and superoxide-dismutase (SOD) activity were measured. We measured TNF-α and IL-6 concentrations. We monitored the activation of anti- and proapoptotic common signaling pathways (bax, bcl-2, p53) during the early phase of reperfusion. Histology was made from kidney samples. RESULTS: GSH concentrations were significantly reduced, MDA concentrations were significantly higher in each group compared to the Sham. SOD enzyme: a pressure of 10 mmHg elicited significantly greater damage than 5 mmHg. There was a significantly higher SOD activity in group 10 mmHg IPC compared to 10 mmHg. We found that the expression of bax was considerably higher in the none conditioned groups. Noticeably higher expression of anti-apoptotic bcl-2 level was measured in 10 mmHg IPC and 10 mmHg IPoC groups. In case of p53 expression: significant decrease could be seen in groups 10 mmHg IPC and 10 mmHg IPoC compared to the 10 mmHg group. CONCLUSION: Based on our results, the elevated intraabdominal pressure due to pneumoperitoneum induces oxidative stress, which is dependent on the applied pressure. Mostly precondiotioning – but also postconditioning – reduces surgical stress following laparoscopic procedures. In order to explore its mechanism it requires further investigations. [ABSTRACT FROM AUTHOR]

Glucose concentration changes in the nucleus tractus solitarius (NTS) affect visceral function and metabolism by influencing central vagal circuits, especially inhibitory, GABAergic NTS neurons. Acutely elevated glucose can alter NTS neuron activity, and prolonged hyperglycemia and hypoinsulemia in animal models of type 1 diabetes results in plasticity of neural responses in the NTS. NTS neurons contributing to metabolic regulation therefore act as central glucose sensors and are functionally altered in type 1 diabetes. Glucokinase (GCK) mediates cellular utilization of glucose, linking increased glucose concentration to excitability changes mediated by ATP-sensitive K + channels (K ATP ). Using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, and in vitro electrophysiology, we tested the hypothesis that changes in GCK expression in the NTS accompany the development of diabetes symptoms in the streptozotocin (STZ)-treated mouse model of type 1 diabetes. After several days of hyperglycemia in STZ-treated mice, RNA expression of GCK, but not Kir6.2 or SUR1, was decreased versus controls in the dorsal vagal complex. Electrophysiological recordings in vitro indicated that neural responses to acute hyperglycemia, and synaptic responsiveness to blockade of GCK with glucosamine, were attenuated in GABAergic NTS neurons from STZ-treated mice, consistent with reduced molecular and functional expression of GCK in the vagal complex of hyperglycemic, STZ-treated mice. Altered autonomic responses to glucose in type 1 diabetes may therefore involve reduced functional GCK expression in the dorsal vagal complex. [ABSTRACT FROM AUTHOR]

Objective: We studied the protective effects of postconditioning (PS) in healthy and hypercholesterolemic rats after renal ischaemia-reperfusion (IR) injury. We aimed to examine cytokine expression and apoptosis in tissue damage after revascularisation (TNF-α levels in serum and tissue). Methods: Male Wistar rats (n = 32) were divided into four groups. The animals of normal feed groups (NF) were fed with normal rat chow and the cholesterol feed groups (CF) were fed with 1.5% cholesterol containing diet for 8 weeks. Anaesthetized rats underwent a 45-min cross-clamping in both kidney pedicles. Ischaemia was followed by 120-min reperfusion with or without PS protocol (group PS vs. IR). Postconditioning was induced by four intermittent periods of ischaemia-reperfusion of 15-s duration each. Serum cholesterol, triglyceride, urea and creatinine levels were determined. Proinflammation was characterized by the measurement of serum TNF-α. Tissue injury in kidney was determined by formaline-fixed, paraffin-embedded tissue sections. Tissue TNF-α levels were determined by immunohistochemistry. Results: Significant elevation was observed in serum TNF-α level after IR injury in normal feed groups, which was reduced by PS. In CF group neither the elevation nor the postconditioning induced reduction were as significant as in the NF groups. In normal feed group PS caused a significant reduction in tissue TNF-α level which was significantly higher in CF. Conclusions: Ischaemic postconditioning proved to be an effective defense against IR in NF groups, but it was ineffective in CF groups in kidney tissue. [ABSTRACT FROM AUTHOR]

Abstract: In situ hybridization, quantitative reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry, and Western blot analysis were applied to study the changes in expression of the major nociceptive ion channel transient receptor potential vanilloid type 1 receptor (TRPV1) after the perineural application of capsaicin or nerve transection. In control rats, quantitative morphometric and statistical analyses of TRPV1 protein and mRNA expression in L5 dorsal root ganglion cells revealed distinct populations of small (type C) and small-to-medium (type B) neurons, which showed very high and moderate levels of TRPV1, whereas larger (type A) neurons mostly did not express this receptor. After either transection or capsaicin treatment of the sciatic nerve, immunohistochemistry and Western blotting demonstrated a massive (up to 80%) decrease in the proportion of TRPV1-immunoreactive neurons and TRPV1 protein at all postoperative survival times. In situ hybridization indicated marked decreases (up to 85%) in the proportion of neurons that expressed TRPV1 mRNA after sciatic nerve transection. In contrast, although perineural treatment with capsaicin resulted in similar substantial decreases in the proportions of type B and C neurons of the L5 dorsal root ganglia 3 days postoperatively, a clear-cut tendency to recovery was observed thereafter. Hence, the proportions of both type B and C neurons expressing TRPV1 mRNA reached up to 70% of the control levels at 30 days postoperatively. In accord with these findings, quantitative RT-PCR revealed a marked and significant recovery in TRPV1 mRNA after perineural capsaicin but not after nerve transection. These observations suggest the involvement of distinct cellular mechanisms in the regulation of the TRPV1 mRNA expression of damaged neurons, specifically triggered by the nature of the injury. The present findings imply that the antinociceptive and anti-inflammatory effects of perineurally applied capsaicin involve distinct changes in neuronal TRPV1 mRNA expression and long-lasting alterations in (post)translational regulation. [Copyright &y& Elsevier]

Introduction: The challenge against reperfusion injury and tissue oxidative stress, especially in vascular surgical interventions has an essential importance to reach the optimal clinical result. Numerous experimental attempts have proved the positive antioxidant effect of vitamin E in both chronic and acute phase models. In our study we monitored the effect of continuous preoperative treatment with vitamin E, on oxidative stress and tissue inflammation reactions developed after reconstructive operations. Patients and methods: 32 patients have been involved in a randomized, prospective study, all suffering from AFS occlusion proved by angiography, and all undergone supragenual reconstruction. Duration of ischemia and amount of tissues under vascular clamping were almost the same in all patients. In the group treated with E-vitamin, we administered 1×200 mg of vitamin E p/o from the preoperative day till the 7th post operative day. Patients of the second group did not receive vitamin E. Materials and methods: Peripheral blood samples were collected immediately before operation and at the end of the second reperfusion hour (early reperfusion period). Late reperfusion period has been monitored by analyzing blood samples taken at 24th hour and 7th day next to the operative ischemia. Among oxidative stress parameters, direct measurement of reactive oxygen intermediator (ROI) and determination of antioxidant state (GSH, Total-SH group, SOD) have been performed. Malondialdehyde was chosen as marker for lipidperoxidation. Inflammation reactions were monitored up on expression of adhesion molecules (CD11a and CD18). We also controlled the oscillation of myeloperoxidase (MPO) activity. Results: Our study has proved that preoperative (from the preoperative day till the 7th post operative day) administration of 200 mg vitamin E could reduce the level of oxidative stress developed after ischemic-reperfusion insult (lipidproxidation, antioxidant enzymes). According to our results, the prooxidant-antioxidant imbalance also diminished in the group with E-vitamin treatment. We proved that elective administration of vitamin E could decrease the WBC activity (MPO activity, free radicals production, expression of adhesion molecules) and its consequential local inflammation process, during early reperfusion. [ABSTRACT FROM AUTHOR]

Abstract: Neurogenic inflammation of the dura mater encephali has been suggested to contribute to the mechanisms of meningeal nociception and blood flow regulation. Recent findings demonstrated that the rat dura mater is innervated by trigeminal capsaicin-sensitive peptidergic nociceptive afferent nerves which mediate meningeal vascular responses through activation of the transient receptor potential vanilloid type 1 (TRPV1) receptor. The present work explored the functional significance of the capsaicin-sensitive subpopulation of dural afferent nerves via their contribution to the meningeal vascular responses evoked through activation of the proteinase-activated receptor 2 (PAR-2). The vascular responses of the dura mater were studied by laser Doppler flowmetry in a rat open cranial window preparation. Topical applications of trypsin, a PAR-2-activator, or Ser–Leu–Ile–Gly–Arg–Leu–amide (SLIGRL-NH2), a selective PAR-2 agonist peptide, resulted in dose-dependent increases in meningeal blood flow. The SLIGRL-NH2-induced vasodilatation was significantly reduced following capsaicin-sensitive afferent nerve defunctionalization by prior systemic capsaicin treatment and by pretreatment of the dura mater with the calcitonin gene-related peptide (CGRP) receptor antagonist CGRP8-37. Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME) an unspecific inhibitor of nitric oxide (NO) production, but not 1-(2-trifluoromethylphenyl) imidazole (TRIM), a neuronal NO synthase inhibitor, also inhibited the vasodilator response to SLIGRL-NH2. The vasodilator responses elicited by very low concentrations of capsaicin (10 nM) were significantly enhanced by prior application of SLIGRL-NH2. The present findings demonstrate that activation of the PAR-2 localized on capsaicin-sensitive trigeminal nociceptive afferent nerves induces vasodilatation in the dural vascular bed by mechanisms involving NO and CGRP release. The results indicate that the PAR-2-mediated activation and sensitization of meningeal capsaicin-sensitive C-fiber nociceptors may be significantly implicated in the pathophysiology of headaches. [Copyright &y& Elsevier]

Background: The indication of surgical treatment in lower limb compartment syndrome mostly depends on the clinical signs which can be often uncertain, resulting in delayed insufficient intervention. Aim: The aim of the study was to evaluate the progression of compartment syndrome by measuring of intracompartmental pressure and monitoring of decreased tissular oxygenation, indicating an insufficient secondary microcirculation. Materials and methods: 16 patients were examined in our study (12 males, 4 females, mean age: 62.7±9.5 years), who underwent acute lower limb revascularization surgery for a critical (lasting more than 4 hours) limb ischemia. The indications were: 5 iliac artery embolizations and 11 femoral artery occlusions. After revascularization, on the second postoperative day, we detected significant lower limb edema and swelling of several grade. To monitor the elevated intracompartmental pressure (ICP) and to evaluate the extremital circulation, we used KODIAG pressure meter and the tissular oxygen saturation (StO2) was measured by near-infrared-spectroscopy. Results: In 12 cases the ICP exceeded the critical 40 mmHg. In these patients the average StO2 was 50–53%, in spite of complete recanalization. In these cases we made urgent, semi-open fasciotomy. In 4 cases, where the clinical aspect showed compartment syndrome, the measured parameters did not indicate a surgical intervention (ICP: 25–35 mmHg, StO2: around normal). Summary: A novel approach in our examination is that, besides empirical therapeutic guidelines generally applied in clinical practice, we established an objective, parameter-based (“evidence based medicine”) surgical indication strategy for the lower limb compartment syndrome. Our parameter results produced by the above pressure and saturation measurements help the clinicians to decide between conservative and operative treatment of the disease. [ABSTRACT FROM AUTHOR]

Objective: We studied the protective effects of ischaemic postconditioning (PS) on ischemia–reperfusion injury of the lower extremities in a rat model of abdominal aortic intervention. We aimed to examine the evoked oxidative stress, cytokine expression and leukocyte activation after revascularisation surgery. Methods: Anesthetized animals (48 Whistar rats) underwent a 60 min infrarenal aorta cross-clamping. After the ischaemic period, an intermittent 4 times 15 s reperfusion – 15 seconds ischaemic episodes – were applied (ischaemic postconditioning: group PS). Then we started a 120 min reperfusion in the aorta. In untreated group animals underwent a long ischaemia (60 min) and the following reperfusion (group IR). Peripherial blood samples were collected before operation, and in early (5, 10, 15, 30, 60 and 120 min) reperfusion periods. Serum peroxide level, TNF-alpha concentration, myeloperoxidase (MPO) activity and PMA-induced leukocyte ROS production were measured. Results: In PS group, plasma peroxide level elevation was significantly lower in very early reperfusion (5–30 min) comparing to non-conditioned IR group (10.04±1.9 μM/l vs. 16.91±3.67 μM/l, p<0.05). PS also reduced serum TNF-alpha concentration (167.41±31.26 μg/ml vs. 116.55±12.04 μg/ml, p<0.05), MPO activity (1.759±0.239 μM/ml vs. 1.22±0.126 μM/ml, p<0.05) and leukocyte activation detected by PMA-induced leukocyte ROS production (5.7±0.96 AU/103 cells vs. 4.63±0.69 AU/103 cells). Conclusions: Ischaemic postconditioning could reduce ROI production after IR in early reperfusion period, thus limiting ROI mediated tissue lesion, cytokine–leukocyte activation and inflammatory responses. PS seems to be an effective tool in vascular surgery to reduce reperfusion injuries after revascularization interventions. [ABSTRACT FROM AUTHOR]

Abstract: Neuropathic alterations of sensory nerves involved in the mediation of neurogenic inflammation of the meninges may contribute to the increased incidence of headaches in diabetics. In the rat, activation of capsaicin-sensitive nociceptors, which express the transient receptor potential vanilloid type 1 (TRPV1) receptor, induces meningeal vasodilatation, a significant component of neurogenic inflammation, through the release of calcitonin gene-related peptide (CGRP). This study examines the effects of streptozotocin-induced diabetes on TRPV1 receptor-mediated neurogenic sensory vasodilatation, CGRP release and nerve fiber density in the rat dura mater. In a cranial window preparation, epidural application of capsaicin (10−7 M) produced distinct vasodilatory responses in control animals as measured by laser Doppler flowmetry. In diabetic rats, capsaicin-induced vasodilatation was reduced or even abolished 6, but not 2 or 4 weeks after diabetes induction. In contrast, vasoconstriction, a non-neurogenic response to capsaicin at a higher concentration (10−5 M), was not altered in diabetic rats. The vasodilatory effects of histamine (10−5 M), acetylcholine (10−4 M) and CGRP (10−5 M) were similar in control, diabetic and insulin-treated diabetic animals. In diabetic rats, a significant decrease in the capsaicin-evoked release of CGRP and reduction in the density of TRPV1-immunoreactive (IR) nerves were demonstrated. Treatment of the diabetic rats with insulin restored both the vasodilatory response and the capsaicin-induced CGRP release toward control values. In conclusion, this study revealed a marked impairment of meningeal TRPV1-IR nerves in streptozotocin diabetic rats by showing reduced neurogenic sensory vasodilatation, decreased capsaicin-evoked CGRP release and reduction in the number of TRPV1-IR nerve fibers of the dura mater. The findings suggest that capsaicin-sensitive afferents may play an important role in meningeal nociceptor function and their dysfunction, e.g. due to a limited removal of inflammatory mediators and/or tissue metabolites from the meningeal tissue, may contribute to the enhanced incidence of headaches in diabetics. [Copyright &y& Elsevier]

Massive bleeding from oesophagus varices presents a life threatening complication of liver cirrhosis. No effective method of treatment is available until now, that would guarantee high grade of patient wellness during the conditioning and investigation phase until the definitive treatment could be introduced. The fact that we have not found any report in the literature about self-expandable metal stents (SEMS) application in acute variceal bleeding had encouraged us to use stents usually used for oesophageal malignancy and furthermore develop a special stent for this individual indication. The aim of this study was to evaluate the tissue response to oesophagus stent designed for stop acute variceal bleeding in animal experiment in compare with another stent used for iatrogenic treatment of different strictures of the oesophagus. Tissue oxygen saturation (StO2) measurement was performed before and after the implantation of the stents. Macroscopic and histological investigations of the stented oesophagus segments were observed after 10 days. Differential scanning calorimeter (DSC) is a well-established method for the demonstration of thermal consequences of local and global conformational changes in biological systems, but it has never been used for the investigation of the oesophagus. According to our results the thermal denaturation of intact oesophagus, its mucosa and muscle fragments revealed significant differences compared to healthy sample in favour of the new stent. [ABSTRACT FROM AUTHOR]

Resection and subsequent end-to-end anastomosis of the windpipe is a tried-and-tested acceptable method for the surgical treatment of segmental defects. There are a variety of different techniques for tracheal end-to-end anastomosis, but controversial reports highlight the fact that the suturing technique of the anastomosis is still subject of debate. We aimed to show the postoperative effects of the continuous and simple interrupted suturing technique respectively on the tracheal cartilage using differential scanning calorimetry. Transsection and subsequent reanastomosis of the cervical trachea was performed in 14 adult beagle dogs. The trachea was anastomized with continuous or simple interrupted sutures respectively depict no change in microcirculation after the resection of the trachea, but significant decrease following the completion the anastomosis with continuous sutures. Conventional histological analysis did not show any marked postoperative change in the tracheal cartilage but our DSC scans clearly demonstrated the differences between the intact cartilages and the ones involved in the anastomosis. [ABSTRACT FROM AUTHOR]

Acquired upper airway stenosis is usually associated with a complex of pathological conditions at the high tracheal and the subglottic levels. Reported reconstructive techniques include widening of the airways by incorporation of grafts, segmental resection, and anastomosis or combined procedures. Progress in anaesthesia, surgical techniques, and understanding of the pathophysiology of the trachea has made primary tracheal reconstruction a safe operative procedure, although there are no reports observing its acute effect on the tracheal cartilage. Differential scanning calorimetry (DSC) is a well-established method for the demonstration of thermal consequences of local and global conformational changes in biological systems, including hyaline cartilage, but it has never been applied for the investigation of tracheal cartilage. According to the present study, the thermograms may prove the presence of structural changes of the cartilage after primary reconstruction in the short-term follow up (smaller melting temperature and calorimetric enthalpy in the operated dog). The differences were clearly demonstrated between the intact cartilages and the ones involved in the anastomosis. [Copyright &y& Elsevier]

Evidence suggests that capsaicin-sensitive substance P (SP)-containing trigeminal ganglion neurons innervate the spiral modiolar artery (SMA), radiating arterioles, and the stria vascularis of the cochlea. Antidromic electrical or chemical stimulation of trigeminal sensory nerves results in neurogenic plasma extravasation in inner ear tissues. The primary aim of this study was to reveal the possible morphological basis of cochlear vascular changes mediated by capsaicin-sensitive sensory nerves. Therefore, the distribution of SP and capsaicin receptor (transient receptor potential vanilloid type 1—TRPV1) was investigated by double immunolabeling to demonstrate the anatomical relationships between the cochlear and vertebro-basilar blood vessels and the trigeminal sensory fiber system.Extensive TRPV1 and SP expression and co-localization were observed in axons within the adventitial layer of the basilar artery, the anterior inferior cerebellar artery, the SMA, and the radiating arterioles of the cochlea. There appears to be a functional relationship between the trigeminal ganglion and the cochlear blood vessels since electrical stimulation of the trigeminal ganglion induced significant plasma extravasation from the SMA and the radiating arterioles.The findings suggest that stimulation of paravascular afferent nerves may result in permeability changes in the basilar and cochlear vascular bed and may contribute to the mechanisms of vertebro-basilar type of headache through the release of SP and stimulation of TPVR1, respectively. We propose that vertigo, tinnitus, and hearing deficits associated with migraine may arise from perturbations of capsaicin-sensitive trigeminal sensory ganglion neurons projecting to the cochlea. [Copyright &y& Elsevier]

Positive excess molar Gibbs energies were detected in liquid mixtures of ([sup 36]Ar+[sup 40]Ar) using a high-accuracy double differential manometric technique. The vapor pressure differences between a mixture of ([sup 36]Ar+[sup 40]Ar) and [sup 40]Ar and between [sup 36]Ar and [sup 40]Ar were measured simultaneously with the vapor pressure of [sup 40]Ar. Four different mixtures were selected and 80 temperatures were chosen in the 85-96 K temperature range. The results show that the vapor pressure of an equimolar liquid mixture is greater than what would be expected if the solution were strictly ideal, by approximately 2.5 Pa in the 85-96 K temperature range. The calculated excess Gibbs energy for the equimolar mixture at 85 K is G[sub 1/2][sup E]=(0.021±0.004) J mol[sup -1]. For the excess molar enthalpy a value of H[sub 1/2][sup E]=(0.12±0.04) J mol[sup -1] was found. The corresponding deviations from Raoult's law are therefore extremely small (3 to 4 orders of magnitude smaller than those typically found in binary mixtures of nonisotopic constituents). The evidence of nonideal behavior in such a fundamental and simple system is relevant for the interpretation of the properties of liquid mixtures of more general importance. The pitfalls of the determination of activity coefficients through the comparison between vapor pressure isotope effect data and liquid-vapor isotope fractionation factors are discussed in some detail. The results were used to test three theoretical models, namely, the vdW-1 fluid theory, the 1cLJ perturbation theory, and the statistical theory of isotope effects in mixtures. While the first two proved to be inadequate, the isotope effect theory agrees reasonably well with experiment. The excess Gibbs energy of monatomic isotopic mixtures are related with the molar volume isotope effect and with the mean Laplacian of the potential energy in the liquid phase. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Quasi-elastic neutron scattering measurements were performed on aqueous solutions of 3-picoline (3-methylpyridine) at room temperature. H-D substitution on both the solute and the water was used to separate the dynamics of the two species. The analysis of the translational diffusive motion at different concentrations shows that at high picoline content the diffusion coefficient of water decreases strongly and becomes similar to that of the solute, indicating strong coupling between the motions of the solute and the solvent. Activation energies characteristic of the dynamic behavior of the methyl group were determined from ¹H spin-lattice relaxation rate measurements for H[sub 2]O and D[sub 2]O solutions of 3-picoline above 310 K. [ABSTRACT FROM AUTHOR]