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Abstract Background Our study aimed to evaluate changes in the contractile behavior of human myocardium after exposure to caffeine and taurine, the main active ingredients of energy drinks (EDs), and to evaluate whether taurine exhibits any inotropic effect at all in the dosages commonly used in EDs. Methods Myocardial tissue was removed from the right atrial appendages of patients undergoing cardiac surgery and prepared to obtain specimens measuring 4 mm in length. A total of 92 specimens were exposed to electrical impulses at a frequency of 75 bpm for at least 40 min to elicit their maximum contractile force before measuring the isometric contractile force (ICF) and duration of contraction (CD). Following this, each specimen was treated with either taurine (group 1, n = 29), or caffeine (group 2, n = 31) or both (group 3, n = 32). After exposure, ICF and CD measuring were repeated. Post-treatment values were compared with pre-treatments values and indicated as percentages. Results Exposure to taurine did not alter the contraction behavior of the specimens. Exposure to caffeine, in contrast, led to a significant increase in ICF (118 ± 03%, p

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Evidence is accumulating that intact endocardium interferes with the mechanical properties of the working myocardium. We studied the role of the endocardial endothelium on muscle contraction, force development and intracellular calcium in vital human atrial trabecula. One group of human atrial tissue (n=9) was treated with the detergent saponin (0.1%). Effectiveness of deendothelialisation was exemplarily approved by Evans-blue staining and light microscopy. An effect of saponin itself on contractility was excluded by exemplarily acquisition of the parameters in intact fibres before and after saponin treatment. Vital fibres without saponin treatment (n=9) served as control. The “time to peak” interval was significantly shorter in the deendothelialisation group (DG) 265.4±14.4 ms vs. 283±14.4 ms in the control group (CG), p=0.034. Diastolic relaxation time was quantified at 75% and 50% of the maximum force developed by each specimen. The DG reached 75% of maximum force at 340±18.7 ms vs. 366.6±22.5 ms in the CG, p=0.020. Relaxation at 50% of maximum force was detected after 389.9±29.2 ms in DG vs. 423.1±34.3 ms in CG, p=0.036. The ability to shorten against a defined afterload (75, 50, 25 and 0% of maximum force) was statistically significantly reduced in the DG for all specimens; it averages a 52.5% reduction. For the measurement of intracellular calcium, the decline to 75, 50 and 25% of the maximum signal was statistically significant: 75%: DG 237.5±46.3 ms vs. CG 287.2±25.9 ms (p=0.022); 50%: DG 352.6±59.5 ms vs. CG 401.4±46.5 ms (p=0.009); 25%: DG 490±72.2 ms vs. CG 556±68.8 ms (p=0.012). The data show that the endothelium plays a crucial role in electromechanical coupling of atrial myocardium. [ABSTRACT FROM AUTHOR]

Background: Accelerometers were traditionally worn on the hip to estimate energy expenditure (EE) during physical activity but are increasingly replaced by products worn on the wrist to enhance wear compliance, despite potential compromises in EE estimation accuracy. In the older population, where the prevalence of hearing loss is higher, a new, integrated option may arise. Thus, this study aimed to investigate the accuracy and precision of EE estimates using an accelerometer integrated into a hearing aid and compare its performance with sensors simultaneously worn on the wrist and hip., Methods: Sixty middle-aged to older adults (average age 64.0 ± 8.0 years, 48% female) participated. They performed a 20-min resting energy expenditure measurement (after overnight fast) followed by a standardized breakfast and 13 different activities of daily living, 12 of them were individually selected from a set of 35 activities, ranging from sedentary and low intensity to more dynamic and physically demanding activities. Using indirect calorimetry as a reference for the metabolic equivalent of task (MET), we compared the EE estimations made using a hearing aid integrated device (Audéo) against those of a research device worn on the hip (ZurichMove) and consumer devices positioned on the wrist (Garmin and Fitbit). Class-estimated and class-known models were used to evaluate the accuracy and precision of EE estimates via Bland-Altman analyses., Results: The findings reveal a mean bias and 95% limit of agreement for Audéo (class-estimated model) of -0.23 ± 3.33 METs, indicating a slight advantage over wrist-worn consumer devices (Garmin: -0.64 ± 3.53 METs and Fitbit: -0.67 ± 3.40 METs). Class-know models reveal a comparable performance between Audéo (-0.21 ± 2.51 METs) and ZurichMove (-0.13 ± 2.49 METs). Sub-analyses show substantial variability in accuracy for different activities and good accuracy when activities are averaged over a typical day's usage of 10 h (+61 ± 302 kcal)., Discussion: This study shows the potential of hearing aid-integrated accelerometers in accurately estimating EE across a wide range of activities in the target demographic, while also highlighting the necessity for ongoing optimization efforts considering precision limitations observed across both consumer and research devices., Competing Interests: NS, SEJK, NCH and EU were employed by Sonova AG. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this study received funding from Sonova AG. The funder had the following involvement with the study: NS, SEJK, NCH and EU individually contributed to different phases of the work (for details, please see Author Contribution). All authors declare no additional competing interests., (© 2024 Stutz, Eichenberger, Stumpf, Knobel, Herbert, Hirzel, Huber, Oetiker, Urry, Lambercy and Spengler.)

Liquid biopsies hold great promise for the management of cancer. Reliable liquid biopsy data depend on stable and reproducible pre-analytical protocols that comply with quality measures, irrespective of the sampling and processing site. We established a workflow for plasma preservation, followed by processing, cell-free nucleic acid isolation, quantification, and enrichment of potentially tumor-derived cell-free DNA and RNA. Employing the same input material for a direct comparison of different kits and protocols allowed us to formulate unbiased recommendations for sample collection, storage, and processing. The presented workflow integrates the stabilization in Norgen, PAX, or Streck tubes and subsequent parallel isolation of cell-free DNA and RNA with NucleoSnap and NucleoSpin. Qubit, Bioanalyzer, and TapeStation quantification and quality control steps were optimized for minimal sample use and high sensitivity and reproducibility. We show the efficiency of the proposed workflow by successful droplet digital PCR amplification of both cell-free DNA and RNA and by detection of tumor-specific alterations in low-coverage whole-genome sequencing and DNA methylation profiling of plasma-derived cell-free DNA. For the first time, we demonstrated successful parallel extraction of cell-free DNA and RNA from plasma samples. This workflow paves the road towards multi-layer genomic analysis from one single liquid biopsy sample.

We present a patient with a painful, mobile nodule on the elbow. The nodule was skin-colored and had no punctum or discharge. It was excised and histopathology showed that the lesion was a glomangioma, or glomuvenous malformation. This is a neoplasm that arises from the glomus body, a thermoregulatory neurovascular structure. The glomus body is composed of glomus cells, vascular cells, and smooth muscle cells. Three subtypes of neoplasms may arise from the glomus body, depending on the extent to which they involve the three types of cells. They include glomus tumors, glomangiomas/glomuvenous malformations, and glomangiomyomas. This case was unusual in that it did not present with surface color change to indicate a vascular component.

Background: Human exposure to infrasound is increasing due to man-made factors, such as occupational conditions, wind farms and transportation. The concern among the public regarding the safety of infrasound exposure is growing., Aims: To evaluate whether exposure to infrasound interferes directly with human cardiac function and contributes to pathological processes., Setting: The University Hospital of Mainz, Germany., Methods: Human myocardial tissues, obtained from patients undergoing cardiac surgery, were prepared in small muscle samples and stimulated electrically in-vitro for a period of almost two hours under physiological conditions to induce continuous pulsatile contractions and simulating a working human heart. Two samples were obtained from each donor: one was subjected to infrasound for 60 min and the other served as a control. Their contraction forces (CF) and durations (CD) were measured before and after each testing period and their relative changes (CF % and CD % ) were calculated and introduced in a multilinear regression model. The following three infrasound levels of exposure were used in this study: 100, 110 and 120 dBz., Results: The measured CF % corresponded negatively with the infrasound level measured in dBz (R 2  = 0.631; P = 0.018). The decrease measured almost -11% at 110 dBz and -18% at 120 dBz, after correction for control. The CD on the other hand remained unchanged., Conclusions: Exposure to high levels of infrasound (more than 100 dBz) interferes with cardiac muscle contractile ability, as early as one hour after exposure. There are numerous additional studies which support this conclusion. These results should be taken into account when considering environmental regulations., Competing Interests: None

Although it is well established that microbial infections predispose to autoimmune diseases, the underlying mechanisms remain poorly understood. After infection, tissue-resident memory T (T RM ) cells persist in peripheral organs and provide immune protection against reinfection. However, whether T RM cells participate in responses unrelated to the primary infection, such as autoimmune inflammation, is unknown. By using high-dimensional single-cell analysis, we identified CD4 + T RM cells with a T H 17 signature (termed T RM 17 cells) in kidneys of patients with ANCA-associated glomerulonephritis. Experimental models demonstrated that renal T RM 17 cells were induced by pathogens infecting the kidney, such as Staphylococcus aureus , Candida albicans , and uropathogenic Escherichia coli , and persisted after the clearance of infections. Upon induction of experimental glomerulonephritis, these kidney T RM 17 cells rapidly responded to local proinflammatory cytokines by producing IL-17A and thereby exacerbate renal pathology. Thus, our data show that pathogen-induced T RM 17 cells have a previously unrecognized function in aggravating autoimmune disease., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: Our study aimed to evaluate changes in the contractile behavior of human myocardium after exposure to caffeine and taurine, the main active ingredients of energy drinks (EDs), and to evaluate whether taurine exhibits any inotropic effect at all in the dosages commonly used in EDs., Methods: Myocardial tissue was removed from the right atrial appendages of patients undergoing cardiac surgery and prepared to obtain specimens measuring 4 mm in length. A total of 92 specimens were exposed to electrical impulses at a frequency of 75 bpm for at least 40 min to elicit their maximum contractile force before measuring the isometric contractile force (ICF) and duration of contraction (CD). Following this, each specimen was treated with either taurine (group 1, n = 29), or caffeine (group 2, n = 31) or both (group 3, n = 32). After exposure, ICF and CD measuring were repeated. Post-treatment values were compared with pre-treatments values and indicated as percentages., Results: Exposure to taurine did not alter the contraction behavior of the specimens. Exposure to caffeine, in contrast, led to a significant increase in ICF (118 ± 03%, p < 0.01) und a marginal decrease in CD (95 ± 1.6%, p < 0.01). Exposure to a combination of caffeine and taurine also induced a statistically significant increase in ICF (124 ± 4%, p < 0.01) and a subtle reduction in CD (92 ± 1.4%, p < 0.01). The increase in ICF achieved by administration of caffeine was similar to that achieved by a combination of both caffeine and taurine (p = 0.2). The relative ICF levels achieved by administration of caffeine and a combination of taurine and caffeine, respectively, were both significantly higher (p < 0.01) than the ICF resulting from exposure to taurine only., Conclusion: While caffeine altered the contraction behavior of the specimen significantly in our in-vitro model, taurine did not exhibit a significant effect. Adding taurine to caffeine did not significantly enhance or reduce the effect of caffeine.

Background/objective: The aim of our study was to evaluate right heart contractile force in patients with diastolic dysfunction (DD) with preserved left heart ejection fraction undergoing cardiac surgery. We examined the contractile properties of skinned human fibers obtained from the right auricle in two groups (DD and controls)., Methods: Right atrial tissue from 64 patients, who were undergoing cardiac surgery, were collected before extracorporal circulation. Tissue was conserved and prepared as "skinned fibers". We exposed the dissected fibers to increasing calcium concentrations and recorded the force values., Results: Patients with DD develop significantly less force at middle and higher calcium concentrations pCa 4.0: DD 2.58 ± 0.4 mN, controls 5.32 ± 0.4 mN, p = 0.02; pCa 5.5: DD 1.14 ± 0.3 mN, controls 1.45 ± 0.3 mN, p = 0.03. DD significantly correlates with left ventricular hypertrophy (LVH; p = 0.03). DD did not significantly occur more often in patients with mitral valve insufficiency, aortic insufficiency or stenosis, or coronary heart disease (all p > 0.10). LVH, which was associated with DD, correlated significantly with mitral valve prolapse (p = 0.05), aortic valve stenosis (p = 0.02), and mitral valve insufficiency (p = 0.03)., Conclusion: Contractile force is significantly reduced in right atrial skinned human fibers with DD. DD is significantly associated with LVH, but emerges independently from underlying pathologies like valve diseases or coronary heart disease. This underlines the hypothesis that impairment of contractile capacity directly results from DD-independent from volume or pressure overload due to valvular or ischemic heart disease., (Copyright © 2015. Published by Elsevier Taiwan.)

Background: Myxomatous degeneration of the mitral valve is a common pathological finding in mitral valve surgery and the most common reason for severe mitral valve regurgitation. Considering the importance of right ventricular remodeling and global function after mitral valve surgery we tried to elucidate a possible association of myxomatous mitral valve and impairment of right atrial and ventricular function, which might have an impact on global ventricular performance after mitral valve surgery., Methods: Right atrial tissue was harvested from 47 patients undergoing mitral valve surgery. We took the trabeculae from the right auricle, which was resected at the right auricle for implementation of extracorporal circulation. The tissue was skinned and prepared in a 24 h-lasting procedure to create small fibers for hinging them in the "muscle machine", an experimental set-up, created for pCa-force measurements., Results: Patients without myxomatous mitral valve developed significantly more force (4.0 mN ± 0.8 mN) at the highest step of calcium concentration compared to 2.7 mN ± 0.4 mN in group of patients with myxomatous valve degeneration (p 0.03). Calcium sensitivity in the myxomatous valve group was at pCa 6.0 and in the non-myxomatous group at pCa 5. Furthermore we observed a significant difference in ejection fraction (EF) among the groups: 49% in the non-myxomatous group versus 57% in the myxomatous group (p 0.03). In the non-myxomatous group 5 patients had diastolic dysfunction grade I-II (22,7%), in group I 10 patients (40%). This was also significant (p 0.04)., Conclusions: Patients with myxomatous mitral valve degeneration seem to have reduced force capacities. Calcium sensitivity is higher compared to the non-myxomatous group, which might be a compensatory mechanism to cover the physiological demand. Furthermore we suggest a higher incidence of diastolic dysfunction in patients with myxomatous mitral valve degeneration, which might have an impact on ventricular remodeling after mitral valve surgery.

Background: Vascular endothelial dysfunction occurs in the kidney graft from marginal brain death (BD) donors and may be responsible for a low success rate after transplantation., Methods: BD was induced in 16 dogs for 6 hours. Immediately after the inflation of the intracranial balloon, the treated group (n = 8) received 40 mg/kg bolus followed by 3 mg/kg/min infusion of L-arginine for 30 minutes. Renal vascular function and hemodynamic and biochemical parameters were determined., Results: BD caused vasoconstriction, increase in renal venous nitrite (4.9 ± 0.8 versus 2.6 ± 0.1, P < .05) and myeloperoxidase levels (1.43 ± 0.04 versus 2.43 ± 0.23, P < .001), and reduced vasodilatation of renal artery to acetylcholine. Larginine diminished the renal vasoconstriction induced by 6 hour BD (RVR = 0.92 ± 0.06 versus 1.38 ± 0.003 in controls, P < .05), maintained renal oxygen extraction in physiological range (17.5 ± 4.6% versus 25.4 ± 2.9% in controls, P < .05) and prevented the rise of myeloperoxidase (1.69 ± 0.19, P < .05 versus controls) and nitrite levels (3.3 ± 0.5, P < .05), followed by preservation of endothelium dependent vasodilatation (P < .05 versus controls)., Conclusions: The findings suggest that exogenous L-arginine supplementation may preserve endothelial vascular function in the kidney before prelevation from marginal BD donors., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Recent studies have suggested that the peroxynitrite-poly(ADP-ribose) polymerase (PARP) pathway is activated during acute allograft rejection. Therefore, we investigated whether PARP inhibition improves transplant outcome and the extent to which immunologic factors contribute to the effects of PARP inhibition., Methods: Isogeneic Lewis-to-Lewis and allogeneic Dark Agouti (DA)-to-Lewis rat cardiac transplants were studied under treatment with placebo, the PARP inhibitor INO-1001 (1 mg/kg/day), cyclosporine (2.5 or 5 mg/kg/day) or the combination of INO-1001 and low-dose cyclosporine. Functional, biochemical and histologic analyses were performed 3 and 5 days after transplantation in control and INO-1001-treated animals. In addition, stimulated T cells and endothelial cells were treated with INO-1001 to evaluate the potential immunosuppressive effects of PARP inhibition., Results: PARP inhibition alone and in combination with cyclosporine significantly prolonged graft survival. Acute rejection led to a typical sequence of initial endothelial dysfunction and reduced contractile reserve followed by progressive systolic and diastolic dysfunction, which were reduced by PARP inhibition. PARP inhibition led to reduced antigen-specific and non-specific proliferation in stimulated T cells and dose-dependently inhibited intracellular adhesion molecule-1 (ICAM-1) up-regulation in stimulated endothelial cells., Conclusions: PARP inhibition was found to prolong graft survival and improve cardiac function during acute cardiac rejection. Direct immunosuppressive properties contribute at least partially to the beneficial effects of PARP inhibitors in graft rejection.

Objective: Inosine, a break-down product of adenosine, has been recently shown to exert inodilatory and anti-inflammatory properties. We investigated the effects of inosine on ischemia/reperfusion injury in a rat heart transplantation model., Methods: Intraabdominal heterotopic transplantation was performed in Lewis rats. After 1h of ischemic preservation, reperfusion was started after application of either saline vehicle (control, n=12) or inosine (100 mg/kg, n=12). Coronary blood flow, left ventricular function, endothelium-dependent vasodilatation to acetylcholine and endothelium-independent vasodilatation to sodium nitroprusside, and high energy phosphate content were measured after 1 and 24h of reperfusion. In addition, the activation of the poly(ADP-ribose) polymerase was detected by immunhistology., Results: After 1h, coronary blood flow (4.1+/-0.3 ml/(ming) vs 2.9+/-0.3 ml/(ming), p<0.05), left ventricular systolic pressure (102+/-9 mmHg vs 83+/-4 mmHg, p<0.05) and dP/dt (2765+/-609 mmHg/s vs 1740+/-116 mmHg/s, p<0.05) were significantly higher in the inosine group in comparison to control. Vasodilatatory response to sodium nitroprusside was similar in both groups. Acetylcholine resulted in a significantly higher increase in coronary blood flow in the inosine group (76+/-5% vs 48+/-9%, p<0.05). Energy charge potential was significantly higher in the inosine group (1.69+/-0.10 micromol/g vs 0.74+/-0.27 micromol/g, p<0.05). After 24h, there was no difference between the groups in basal coronary blood flow, left ventricular systolic pressure, dP/dt, and the response to sodium nitroprusside. However, acetylcholine led to a still significantly higher response in the inosine group (112+/-13% vs 88+/-7%, p<0.05). Immunhistologic stainings revealed activation of poly(ADP-ribose) polymerase in control animals which was abolished by inosine., Conclusions: Thus, inosine improves myocardial and endothelial function during early reperfusion after heart transplantation with a persisting beneficial effect against reperfusion induced graft coronary endothelial dysfunction. The effects of inosine are mediated at least partly by modulation of the peroxynitrite-poly(ADP-ribose) polymerase pathway.

Recent studies suggested that the peroxynitrite-poly (ADP-ribose) polymerase (PARP) pathway is activated during acute allograft rejection. We investigated whether PARP inhibition improves transplant function during cardiac rejection. Isogeneic Lewis-to-Lewis and allogeneic Dark Agouti-to-Lewis rat cardiac transplants were studied under treatment with placebo or with the PARP-inhibitor INO-1001 (1 mk/kg/day), Functional, biochemical and histological analysis were performed 3 and 5 days after transplantation. After 3 days, baseline left ventricular pressure-volume relationships did not differ between the groups. However, coronary blood flow (4.3 +/- 0.5 vs. 2.2 +/- 0.2 vs. 4.1 +/- 0.3 ml/min/g, P < 0.05) and contractile response to dobutamine (Delta+dP/dt: 98 +/- 11 vs. 57 +/- 7 vs. 88 +/- 8%, P < 0.05) decreased significantly in the placebo group, which was abolished by INO-1001. Vasodilatory response to acethylcholine was reduced in the placebo group (78 +/- 6 vs. 36 +/- 9 vs. 72 +/- 7%, P < 0.05). After 5 days, baseline systolic and diastolic pressure-volume relationships were impaired (P < 0.05) in the placebo group and the response to dobutamine and to acethylcholine deteriorated further which was abolished by INO-1001. Histology confirmed mild to moderate rejection after 3 days and severe acute rejection after 5 days in the allogeneic groups. Thus, contractile and vasomotor dysfunction occur in a typical time dependent manner during cardiac rejection, which can be reduced by PARP-inhibition.

Objective: Free radical production and related cytotoxicity during ischemia and reperfusion might lead to DNA strand breakage, which activates the nuclear enzyme poly-ADP-ribose synthetase and initiates an energy-consuming and inefficient cellular metabolic cycle with transfer of the adenosine diphosphate-ribosyl moiety of nicotinamide adenine dinucleotide (NAD(+)) to protein acceptors. We investigated the effects of poly-ADP-ribose synthetase inhibition on myocardial and endothelial function during reperfusion in an experimental model of cardiopulmonary bypass., Methods: Twelve anesthetized dogs underwent hypothermic cardiopulmonary bypass. After 60 minutes of hypothermic cardiac arrest, reperfusion was started after application of either saline vehicle (control, n = 6) or PJ34 (10 mg/kg), a potent poly-ADP-ribose synthetase inhibitor (n = 6). Biventricular hemodynamic variables were measured by means of a combined pressure-volume conductance catheter, and the slope of the end-systolic pressure-volume relationships was calculated at baseline and after 60 minutes of reperfusion. Left anterior descending coronary blood flow, endothelium-dependent vasodilatation to acetylcholine, and endothelium-independent vasodilatation to sodium nitroprusside were also determined., Results: The administration of PJ34 led to a significantly better recovery of left and right ventricular systolic function (P <.05) after 60 minutes of reperfusion. In addition, the inotropic adaptation potential of the right ventricle to an increased afterload was better preserved in the PJ34 group. Coronary blood flow was also significantly higher in the PJ34 group (P <.05). Although the vasodilatory response to sodium nitroprusside was similar in both groups, acetylcholine resulted in a significantly higher increase in coronary blood flow in the PJ34 group (P <.05)., Conclusions: Poly-ADP-ribose synthetase inhibition improves the recovery of myocardial and endothelial function after cardiopulmonary bypass with hypothermic cardiac arrest.

Background: The aim of our study was to determine whether addition of the nitric oxide donor l-arginine at reperfusion may prevent the cardiopulmonary bypass (CPB)-induced vascular alterations in the intestine., Methods: Twelve dogs underwent 90-minute hypothermic CPB. After 60 minutes, the cardiac arrest-treated group (n = 6) received 40 mg/kg intravenous bolus l-arginine, followed by 3 mg/kg/min infusion for 20 minutes. Hemodynamic parameters, blood gases, lactate, and glucose were monitored. Reactive hyperemia (RH) in response to superior mesenteric artery ischemia and vasorelaxation to systemically administered vasoactive drugs (acetylcholine [ACH] and sodium nitroprusside) were assessed before and after CPB and defined as percent change of vascular resistance., Results: In the control group, CPB reduced reactive hyperemia (RH) (-26 +/- 15% vs -53 +/- 5%), and the response to ACH (-30 +/- 3% vs -42 +/- 7%). In the treated group, the post-CPB endothelial dysfunction was reversed (-37 +/- 1%, P <.05 vs control group) and RH partially recovered (-34 +/- 4%, P <.05). Administration of l-arginine resulted in a higher mesenteric oxygen delivery, increased nitrite/nitrate production, and lower lactate release from the mesenteric vascular circulation after reperfusion., Conclusions: CPB disrupts some of the regulatory functions of the endothelial cell in the mesenterium and these are mostly related to nitric oxide unavailability. Systemic supplementation of l-arginine at reperfusion prevents the CPB-induced mesenteric endothelial dysfunction in association with an increased blood distribution and a reduced metabolic impairment.

The tobacco whitefly, Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) is a serious pest in numerous cropping systems and has developed a high degree of resistance against several chemical classes of insecticides. One of the latest group of insecticides introduced to the market were the neonicotinoids (chloronicotinyls), acting agonistically on insect nicotinic acetylcholine receptors. Resistance to neonicotinoid insecticides has recently been shown to occur, especially in Q-type B tabaci in some places in Almeria, Spain, whereas control of B-type B tabaci in many other intense cropping systems worldwide has remained on high levels. Our study revealed that neonicotinoid-resistant Q-type strains from Almeria were often more than 100-fold less susceptible to thiamethoxam, acetamiprid and imidacloprid when tested in discontinuous systemic laboratory bioassays. The resistance factors were generally 2- to 3-fold lower in leaf-dip bioassays. In addition to the Spanish strains, we obtained two other highly neonicotinoid-cross-resistant B tabaci greenhouse populations, one from Italy (December 1999) and one from Germany (June 2001). A molecular diagnostic analysis revealed that both strains also belong to the (Spanish) subtype Q of the B tabaci species complex. The resistance levels of Q-type whitefly strains derived from Almeria greenhouses in 1999 remained stable for at least two years, even when maintained in the laboratory without any selection pressure. The biochemical mechanisms conferring resistance to neonicotinoids have not yet been elucidated in detail, but synergist studies suggested a possible involvement of microsomal monooxygenases. Furthermore, we checked two Almerian strains of B tabaci isolated in 1998 and 1999 and demonstrated that neonicotinoid resistance is not due to an altered [3H]imidacloprid binding site of nicotinic acetylcholine receptors.

Elevated levels of glutathione S-transferases (GSTs) play a major role as a mechanism of resistance to insecticides and acaricides in resistant pest insects and mites, respectively. Such compounds are either detoxicated directly via phase I metabolism or detoxicated by phase II metabolism of metabolites as formed by microsomal monooxygenases. Here we used monochlorobimane (MCB) as an artificial substrate and glutathione to determine total GST activity in equivalents of single pest insects and spider mites in a sensitive 96-well plate-based assay system by measuring the enzymatic conversion of MCB to its fluorescent bimane-glutathione adduct. The differentiation by their GST activity between several strains of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), with different degrees of resistance to numerous acaricides was more sensitive with MCB compared to the commonly used substrate 1-chloro-2,4-dinitrobenzene (CDNB). Compared to an acaricide-susceptible reference strain, one field population of T. urticae showed a more than 10-fold higher GST activity measured with MCB, in contrast to a less than 2-fold higher activity when CDNB was used. Furthermore, we showed that GST activity can be sensitively assessed with MCB in homogenates of pest insects such as Heliothis virescens, Spodoptera frugiperda (Lepidoptera: Noctuidae), Plutella xylostella (Lepidoptera: Yponomeutidae), and Myzus persicae (Hemiptera: Aphididae)., ((C)2002 Elsevier Science (USA))

Background: This study investigated the changes of catecholamine responsiveness and beta-adrenergic receptor/adenylyl cyclase pathway during acute cardiac transplant rejection., Methods: Isogeneic Lewis to Lewis and allogeneic Dark Agouti (DA) to Lewis rat cardiac transplants were studied 3 and 5 days after heterotopic intraabdominal transplantation (n=6/group). Myocardial blood flow (MBF), left ventricular systolic pressure (LVSP), maximum pressure development (+dP/dt), and end-diastolic pressure (LVEDP) were measured using an intraventricular balloon. Contractile response to dobutamine (5 microg/kg/min) was also assessed. In separate groups beta-adrenergic receptor density and adenylyl cyclase activity were measured in the grafts, in the recipients' native hearts and in native hearts of sham-operated controls., Results: During mild to moderate rejection cardiac function indices remained unchanged, although MBF and contractile response to dobutamine decreased significantly (P<0.05) in the allogeneic group. The beta-adrenergic receptor density was significantly (P<0.05) increased in both isografts and allografts and in the native hearts of allografted recipients in comparison to native hearts of controls. Adenylyl cyclase activity showed a significant decrease (P<0.05) only in allografts. During severe rejection, LVSP and +dP/dt decreased and LVEDP increased in allografts in comparison to isografts (P<0.05). This was accompanied by a significant decrease in MBF, contractile response to dobutamine, beta-adrenergic receptor density, and adenylyl cyclase activity (P<0.05)., Conclusions: Both microcirculatory disturbances and primary alteration in adenylyl cyclase activity may contribute to decreased contractile reserve in mild to moderate cardiac allograft rejection, whereas beta-adrenergic receptor density seems to be also influenced by cardiac denervation. Severe rejection leads to systolic and diastolic heart failure with complex dysregulation of the beta-adrenergic receptor/adenylyl cyclase pathway and impaired microcirculation.

The aim of the present study was to investigate the effects of the novel poly(ADP-ribose) polymerase (PARP) inhibitor PJ34 (N-(6-oxo-5,6-dihydro-phenanthridin-2-yl)-N,N-dimethylacetamide) on myocardial and endothelial function after hypothermic ischemia and reperfusion in a heterotopic rat heart transplantation model. After a 1-hour ischemic preservation, reperfusion was started either after application of placebo or PJ34 (3 mg/kg). The assessment of left ventricular pressure-volume relations, total coronary blood flow, endothelial function, myocardial high energy phosphates, and histological analysis were performed at 1 and 24 hours of reperfusion. After 1 hour, myocardial contractility and relaxation, coronary blood flow, and endothelial function were significantly improved and myocardial high energy phosphate content was preserved in the PJ34-treated animals. Improved transplant function was also seen with treatment with another, structurally different PARP inhibitor, 5-aminoisoquinoline. The PARP inhibitors did not affect baseline cardiac function. Immunohistological staining confirmed that PJ34 prevented the activation of PARP in the transplanted hearts. The activation of P-selectin and ICAM-1 was significantly elevated in the vehicle-treated heart transplantation group. Thus, pharmacological PARP inhibition reduces reperfusion injury after heart transplantation due to prevention of energy depletion and downregulation of adhesion molecules and exerts a beneficial effect against reperfusion-induced graft coronary endothelial dysfunction.

Resistance of the twospotted spider mite, Tetranychus urticae Koch, to acaricides acting as mitochondrial electron transport inhibitors (METIs) is an increasing problem. Because of their high levels of cross-resistance to all commercially available METI-acaricides, a Japanese strain (AKITA) and an English strain (UK-99) of T. urticae were investigated in detail. Larvae of both strains, AKITA and UK-99, showed 1,100- and 480-fold resistance against pyridaben, 870- and 45-fold resistance against fenpyroximate, and 33- and 44-fold resistance against tebufenpyrad, respectively, in a foliar spray application bioassay compared with the susceptible strain GSS. These resistance factors remained stable even when maintained in the laboratory without further selection. Furthermore, strain AKITA showed cross-resistance to dicofol. The METI resistant strains AKITA and UK-99 showed 2.4- and 1.7-fold enhanced O-ethoxycoumarin O-deethylation (cytochrome P450) activity. Increased oxidative metabolism of the METI-acaricides in the resistant strains could be partially suppressed in vivo by the monooxygenase-inhibitor piperonyl butoxide. Reciprocal crosses of homozygous, diploid females and hemizygous, haploid males of strains GSS (susceptible) and AKITA (resistant) revealed that resistance to pyridaben and fenpyroximate was inherited incompletely dominant with slight differences between maternal and paternal inheritance. This is the first attempt to mechanistically describe METI-acaricide resistance in T. urticae. The implications for resistance management strategies are discussed.

The aim of the study was to characterize the course of systolic and diastolic function, myocardial blood flow, and histologic changes during acute rejection in a model of heterotopic transplantation in rats. For this purpose isogenic Lewis-to-Lewis and allogenic DA (Dark Agouti)-to-Lewis rat cardiac transplants were studied 1 hour and 1, 3, and 5 days, respectively, after heterotopic intraabdominal transplantation. Myocardial tissue blood flow (MBF) was assessed by the hydrogen-clearance method. An implanted balloon was used to measure pressure-volume relations in the transplanted heart. Myocardial water content was determined at the end of the experiments, and histologic examinations were performed. The MBF recovered during the first day postoperatively in both groups and decreased again in the allogenic group after 3 and 5 days (p < 0.05); it remained stable in the isogenic group. Myocardial relaxation was already prolonged in the allogenic group after 3 days and deteriorated further. Left ventricular end-diastolic pressure progressively increased in the allogenic group, whereas it remained unchanged in the isogenic group up to 5 days. After recovery from ischemia, the left ventricular peak systolic pressure was stable in the isogenic group for the entire further observation period, but it significantly decreased in the allogenic group after 5 days (p < 0.05). Myocardial water content showed a significant increase in the allogenic group compared to that in the isogenic group after 5 days. In the allogenic group histologic examination confirmed mild to moderate rejection after 3 days and severe acute rejection after 5 days. Thus, after recovery from ischemia, mild to moderate cardiac rejection was associated with reduced MBF and impaired relaxation. In a typical sequence, generation of edema and impaired diastolic compliance were terminally followed by systolic dysfunction during severe rejection.

The toxicities of eight structurally different acaricidal compounds to six-legged larvae (first motile stage) of three laboratory strains of the two-spotted spider mite, Tetranychus uritcae, and the European red mite, Panonychus ulmi, were evaluated following spray application. The larvae of five field-derived strains of T urticae originating from France, Italy, Brazil, California and Florida were also tested for their susceptibilities to discriminating concentrations of several acaricides resulting in 95% mortality when applied to the organophosphate-resistant laboratory reference strain WI. The spray bioassay used was robust and gave repeatable results with a wide range of acaricidal compounds, irrespective of their mode of action (ovo-larvicides or primarily acting on motile life stages). Compounds tested were abamectin, azocyclotin, chlorpyrifos, clofentezine, deltamethrin, fenpyroximate, hexythiazox and pyridaben. Larvae of one of the laboratory strains of T urticae, AK, originally collected in Japan in 1996 and maintained without further selection pressure, exhibited 2000- and > 4000-fold resistance to the mitochondrial electron transport inhibitors pyridaben and fenpyroximate, respectively. Another strain of T urticae, AU, obtained from Australia and maintained in the laboratory under selection with hexythiazox and clofentezine since 1987 showed > 770- and > 1000-fold resistance to clofentezine and hexythiazox, respectively. The same resistance pattern was observed against larvae of a laboratory strain of P ulmi, CE, also selected with hexythiazox. Larvae of one of the field-derived strains of T urticae, BR, showed a lower susceptibility to a number of compounds, whilst the others were susceptible to all compounds except the organophosphates.

Background: It has been previously suggested that triiodothyronine (T3) may reverse depressed cardiac contractile performance occurring after excessive catecholamine stimulation. We therefore investigated the effects of T3 on intracellular calcium transients and contractile performance in isolated ventricular rat myocytes., Methods: Isolated rat myocytes were loaded with the calcium indicator FURA-2/AM (50 micromol/L) and superfused with Krebs-Henseleit solution (pH 7.4). Cells were illuminated by ultraviolet light and fluorescent images obtained with a target camera at 340 nm and 380 nm excitation wavelengths (ratio method). Simultaneous measurements of calcium transients and cell shortening (35 degrees C, electrical field stimulation: 0.5 Hz) were done. At steady state conditions, FURA-2 loaded myocytes were superfused for 60 min with epinephrine (0.1 micromol/L). After 60 min the effect of T3 (10 micromol/L) on calcium transients and shortening were measured. As control, only the effect of 10 micromol/L T3 was analyzed., Results: Epinephrine significantly increased cell shortening and FURA-2 signals to 148.6+/-8.8% and 109.5+/-3.1% (p < 0.01: n = 21; 5 min) respectively. With longer epinephrine exposure, the increase in cell shortening continuously declined to 134.6+/-7.9% with no change in FURA-2 fluorescence. Acute administration of T3 after epinephrine exposure lowered contractile performance from 136.2 +/- 15.5% to 102 +/- 8.2 %, after 10 minutes. In control experiments acute administration of T3 increased basal contractile response from 100% to 115.8+/-3.3% (p<0.01; n = 8; 5 min)., Conclusions: This study confirms previous reports of impaired cardiac function after high catecholamine exposure. High catecholamine exposure is associated with a desensitization of contractile proteins for calcium. Acute T3 administration increased contractility in untreated myocytes, but further depressed myocyte shortening in epinephrine-treated cells. Our results show that T3 is ineffective at restoring myocardial contractility after excessive catecholamine stimulation.

Objective: Previous studies suggested that endothelin-1 (ET-1) may play a pathophysiological role in myocardial ischemia/reperfusion injury. This study was designed to investigate the effects of the selective ET-A receptor antagonist BQ123 and the selective ET-B receptor antagonist BQ788 on myocardial and endothelial function after reversible deep hypothermic ischemia in a heterotopic rat heart transplantation model., Methods: Isogenic intraabdominal heterotopic transplantation was performed in Lewis rats. After 1 h of cold ischemic preservation reperfusion was started either after application of placebo (control), BQ123 (3 mumol/kg/min). BQ788 (3 mumol/kg/min), ET-1 (8 pmol/kg/min) or simultaneous infusion of BQ123 or BQ788 and ET-1, respectively (n = 12 each). An implanted balloon was used to obtain pressure-volume relations of the transplanted heart. Myocardial blood flow (MBF) was assessed by the hydrogen-clearance method. Measurements were taken after 1 and 24 h of reperfusion. Endothelium-dependent vasodilation to acetylcholine (ACH) and endothelium-independent vasodilation to sodium nitroprusside were also determined., Results: Both BQ123 and BQ788 significantly improved myocardial and endothelial functional recovery during early reperfusion, whereas ET-1 significantly impaired myocardial and endothelial function. Simultaneous infusion of ET-1 diminished the effects of BQ123 and BQ788. Although myocardial function and baseline MBF were similar in all groups after 24 h of reperfusion, endothelium dependent vasodilation to ACH was still significantly higher in the BQ123 and BQ788 groups and lower in the ET-1 groups (p < 0.05)., Conclusions: These results suggest that endogenous ET release is involved in the pathogenesis of reperfusion injury after heart transplantation. ET-A and ET-B receptor antagonists may be useful to reduce ischemia/reperfusion injury.

Global myocardial ischemia and reperfusion injury play a major role in early postoperative myocardial graft dysfunction. The aim of the present study was to investigate the effects of the nitric oxide (NO) precursor L-arginine on myocardial and endothelial function after hypothermic ischemia and reperfusion in a heterotopic rat heart transplantation model. After 1 hour ischemic preservation, reperfusion was started after application of placebo (control, n = 12) or L-arginine (L-Arg 40 mg/kg, n = 12), a substrate of NO synthesis. Myocardial blood flow (MBF) was assessed by the hydrogen clearance method. An implanted balloon was used to obtain pressure-volume relations of the transplanted heart. Left ventricular developed pressure (LVDP), rate of pressure development (dP/dt), end-diastolic pressure (LVEDP), isovolumic relaxation constant (TE), and MBF were measured after 60 minutes and 24 hours of reperfusion. endothelium-dependent vasodilatation in response to acetylcholine (ACh) and endothelium-independent vasodilatation in response to sodium nitroprusside (SNP) were also determined. After 1 hour the MBF was significantly higher in the L-Arg group (3.6 +/- 0.6 vs. 1.9 +/- 0.2 ml/min/g, p < 0.05). The L-Arg group showed better recovery of systolic function and myocardial relaxation (LVDP 106 +/- 6 VS. 70 +/- 7 mmHg, p < 0.05; maximal dP/dt 5145 +/- 498 vs. 3410 +/- 257 mmHg/s, P < 0.05; TE 12.1 +/- 0.9 vs. 16.1 +/- 1.5 ms, p < 0.05, at an intraventricular volume of 80 microliters). LVEDP was similar in the two groups. After 24 hours no difference was found between the groups for basal MBF, LVP dP/dt, TE, LVEDP, or the response of MBF to SNP. However, ACh led to a significantly higher increase in MBF in the L-Arg group (52 +/- 8% vs. 29 +/- 7%, p < 0.05). These results indicate that (1) NO donation improves myocardial and endothelial functional recovery during early reperfusion after heart transplantation; and (2) initial treatment with L-Arg has a persisting beneficial effect against reperfusion-induced graft coronary endothelial dysfunction during late reperfusion.

Background: This study was designed to investigate the effects of the selective endothelin-A receptor antagonist BQ123 on myocardial and endothelial function after reversible deep hypothermic ischemia and reperfusion., Methods: Isogenic intra-abdominal heterotopic heart transplantation was performed in Lewis rats. After one hour of cold ischemic preservation reperfusion was started after application of either saline vehicle or BQ123 (1 micromol/L). Left-ventricular pressure-volume relations and myocardial blood flow were assessed after one and 24 hours of reperfusion. Responses to endothelium-dependent vasodilator acetylcholine and endothelium-independent vasodilator sodium nitroprusside were also determined., Results: BQ123 significantly improved myocardial contractility, as indicated by the leftward shift of the systolic pressure-volume relation and significantly increased myocardial blood flow during early reperfusion (p < 0.05). Although myocardial function and baseline myocardial blood flow were similar in both groups after 24 hours of reperfusion, endothelium-dependent vasodilatation was still significantly higher in the BQ123 group (p < 0.05)., Conclusions: These results suggest that endothelin-A receptor antagonists may be useful in reducing ischemia/reperfusion injury after heart transplantation by preservation of myocardial and endothelial function.