Analysis of p53 mutational events and MDM2 amplification in canine soft-tissue sarcomas

Canine cancer is of major significance in terms of animal health and welfare and soft tissue sarcomas are an important group of tumours accounting for approximately 15% of all canine tumours presented. Abnormal p53 protein expression and gene mutations have been identified in a number of different canine tumour types. However, mdm2 gene amplification has only been investigated in a limited number of canine osteosarcomas. In this present study a series of canine soft-tissue sarcomas (STS) were examined for p53 mutations and/or mdm2 amplification. For p53 mutational studies polymerase chain reaction and direct DNA sequencing was used. Gene mutations were identified in 6 of 30 (20%) primary tumour cases including MPNST (n=3) leiomysarcoma (n=1), heamangiosarcoma (n=1) and sarcoma (n=1). mdm2 gene amplification was assessed by Southern Blot. Although there was no evidence for major gene rearrangements, gene amplification was detected in 4 of 35 (11.4 %) primary tumours including MPNST (n=2), rhabdomyosarcoma (n=2). A total of 33 cases were examined for both p53 mutations and mdm2 amplification. Seven of the tumours were positive for p53 mutations, while five were positive for mdm2 amplification. With the exception of one case, a reciprocal relationship between the presence of a p53 mutation and mdm2 gene amplification was demonstrated.

Georeferenced aquatic fate simulation of cleaning agent and detergent ingredients in the river Rur catchment (Germany)

The Geography-referenced regional exposure assessment tool for European rivers (GREAT-ER) 1.0 was developed in the context of environmental risk assessment of chemicals to calculate the aquatic fate of 'down-the-drain' chemicals in surface waters due to point release. As a follow-up project, the river Rur catchment in Germany was incorporated into the system. This included aspects of data collection, modelling and monitoring. Investigated substances are the four detergent and cleaning agent ingredients boron, linear alkylbenzene sulfonate (LAS), nitrilotriacetate (NTA) and ethylenediaminetetraacetate (EDTA). Results of the catchment's incorporation into the system and a comparison of GREAT-ER simulations with different monitoring results are both given. It is shown that data sets derived from a literature review can be used to calculate concentration profiles that are in the range of measured values. Since the model establishes a causal relationship between emission sites and data on the one hand, and observed concentrations in the receiving surface waters on the other, the simulation results can be used to explain monitoring data.

Expression of endomyocardial nitric oxide synthase and coronary endothelial function in human cardiac allografts

BACKGROUND

Inducible nitric oxide synthase (iNOS) is expressed and is functionally active in the presence of transplant arteriosclerosis. However, the early involvement of iNOS in alterations of microvascular endothelial function in the absence of preexisting lesions remains unclear; this information would be of prognostic value. We studied the course of iNOS mRNA expression, transcardiac nitric oxide production, and their potential association with microvascular coronary endothelial dysfunction in human cardiac allografts.

METHODS AND RESULTS

A total of 42 patients were studied at 1, 6, and 12 months after heart transplantation. Microvascular coronary flow velocity reserve (CFVR) was tested in an endothelium-dependent (acetylcholine) and -independent manner (adenosine) using a Doppler flow wire. Endomyocardial iNOS expression was determined by reverse transcription polymerase chain reaction. iNOS protein and nitrotyrosine levels were detected by immunohistochemistry. Transcardiac plasma nitrite/nitrate (NOx) levels were measured by the Griess reaction. CFVR was impaired in 26.1% of patients (n=11) at 1 month and in 31% of patients (n=13) at 12 months after heart transplantation. Patients who developed impaired CFVR in the first year showed a significant increase in iNOS gene expression. Patients with impairment of CFVR 1 month after heart transplantation had higher levels of iNOS mRNA than patients with a normal CFVR. Patients with an initial impairment of CFVR who did not improve over time presented with significantly higher iNOS mRNA levels. iNOS protein and nitrotyrosine were expressed in the endomyocardial vessels of patients with impaired CFVR. Transcardiac NOx release was higher in patients with impaired CFVR.

CONCLUSIONS

In human cardiac allografts, microvascular endothelial dysfunction is associated with an enhanced endomyocardial iNOS mRNA expression and higher transcardiac NOx production and is accompanied by the expression of nitrotyrosine protein, suggesting peroxynitrite plays a role in the disease process. The data from the present study suggest an important role for the iNOS/nitric oxide pathway in the regulation of microvascular function in the absence of preexisting atherosclerotic lesions.

Comparison of different life-cycle impact assessment methods for aquatic ecotoxicity

Human and ecotoxicity impact categories are problematic to quantify within life-cycle impact assessment (LCIA) because their local scope makes them difficult to aggregate with the traditional global-impact categories used in life-cycle assessment (LCA). For being able to assess local impacts such as toxicity, LCIA developers increasingly include fate modeling into LCA. This article follows this development by comparing different LCIA methods for aquatic ecotoxicology and by investigating the importance of fate within LCIA, the necessity of considering freshwater and seawater compartments separately, and the key degradation and intermedia transfer processes involved. The methods are compared by assessing an example study of domestic clothes washing in former West Germany. Four LCIA methods are selected and applied to four substances emitted during the washing process. The conclusion is that the consideration of environmental fate does matter and that aquatic ecotoxic impacts can differ significantly for the same substance in freshwater and in marine ecosystems. The way (bio)degradation, photolysis, volatilization, and transfer from agricultural soils are considered plays an important role as do the system boundaries chosen. This means that the LCIA methodology should remain flexible so that appropriate methods can be chosen for different applications. Fate models being developed in the environmental risk assessment of chemicals can contribute to the further improvement of LCIA methods.

Effects of Celsior and University of Wisconsin preservation solutions on hemodynamics and endothelial function after cardiac transplantation in humans: a single-center, prospective, randomized trial

Optimal preservation of the myocardium remains a major concern in clinical and experimental heart transplantation. The present study compared the efficacy of University of Wisconsin (UW) and Celsior preservation solution with respect to myocardial performance, epicardial and microvascular endothelial vasomotor function and myocardial expression of endothelin and nitric oxide synthases in humans. Forty-one cardiac transplant recipients received either UW (n = 20) or Celsior (n = 21) preserved hearts. Catecholamine and vasodilator requirements were assessed within the first 5 postoperative days. Left ventricular performance and endothelial function was assessed 1 month after transplantation. Endothelin and nitric oxide synthase gene expression were detected in myocardial biopsy samples. Celsior preserved hearts required significantly more catecholamines and vasodilators within the first 5 postoperative days. Myocardial performance and endothelial function were comparable 1 month after transplantation. Total ischemic time correlated with impaired endothelial function in the Celsior but not in the UW group. Endothelin and inducible nitric oxide synthase gene expression were significantly higher in the Celsior group. The results of the study show that both solutions provide myocardial protection with regard to left ventricular performance and endothelial function 1 month after cardiac transplantation. The necessity for higher vasodilator and catecholamine therapy in Celsior preserved hearts suggests post-ischemic myocardial stunning within the first 5 postoperative days. The positive correlation between impaired endothelial function and total ischemic time in the Celsior group requires longitudinal investigation in particular with regard to the development of allograft vasculopathy.

An association between microvascular endothelial dysfunction, transcardiac nitric oxide production and pro-inflammatory cytokines after heart transplantation in humans

Endothelial dysfunction anticipates the development of transplant coronary artery disease (TxCAD) observed more than 1 year after transplantation (HTx). We investigated whether in patients early after HTx myocardial inducible and constitutive nitric oxide synthases (iNOS; cNOS) are expressed and cardiac nitric oxide production occurs. Moreover, a possible relationship to alterations in endothelium dependent and independent vasomotor function was assessed. Forty-two transplant recipients were studied 37 +/- 5 days after HTx. Microvascular coronary flow velocity reserve (CFVR) was tested endothelium dependent (acetylcholine; 30 microg/min x 5 min/i.c.) and independent (adenosine; 160 microg/min x 5 min/i.c.) by Doppler flow wire. Flow velocity increase by a factor greater than 2 was considered normal. Quantitative coronary angiography was used to assess epicardial vasomotor function in response to the same stimuli. Myocardial iNOS and cNOS gene expression were detected by semiquantitative reversed transcriptase polymerase chain reaction. Plasma nitrite levels (microM) were measured by spectrophotometry. Cytokines (TNF-alpha, IL-6; pg/ml) were measured by enzyme linked immunosorbent assay. In 26.1% of patients (n = 11; group A) an impaired endothelium dependent CFVR (1.65 +/- 0.23 increase) was observed; in 73.9% (n = 31, group B) a normal endothelium dependent CFVR (3.0 +/- 0.7 increase; P = 0.003) was observed. Myocardial iNOS and cNOS gene expression did not differ between the two groups. Transcardiac cytokine production was noted in 58.8% of patients for IL-6 and in 53.3% for TNF-alpha. Coronary sinus (CS) levels of TNF-alpha, IL-6 and nitrite were higher in group A. A significant increase in nitrite production was found only in patients with impaired endothelium dependent CFVR (aorta: 43.9 +/- 3.7 vs CS: 52.8 +/- 5.6, P = 0.05), suggesting transcardiac nitric oxide production. In addition, CS nitrite levels correlated with CS TNF-alpha levels in patients with impaired CFVR (r = 0.44, P = 0.003). Microvascular endothelium dependent CFVR is impaired in 26% of patients early after HTx. Activation of cytokines and the NO pathway seem to be involved in this vasomotor dysfunction The association between cardiac nitric oxide production and TNF-alpha in this group indicates a chronic high immunologic process, which may represent an early and important target for therapy and prevention of TxCAD.

Coronary flow reserve and nitric oxide synthases after cardiac transplantation in humans

OBJECTIVE

Coronary endothelial dysfunction may precede morphological changes in both the epicardial conduit and microvascular resistance vessels in heart transplant recipients. Since the development of transplant atherosclerosis is the major limiting factor for long-term survival, the identification of early mediators of vasomotor dysfunction may be of therapeutic interest. We therefore investigated the potential relationship between the expression of nitric oxide synthases (NOS) and coronary endothelial function in human cardiac transplant recipients over time.

METHODS

Forty-two human cardiac transplant recipients were studied at 1 and 12 months after heart transplantation (HTx). The microvascular coronary flow velocity reserve (CFVR) was tested for endothelium-dependent (acetylcholine) and -independent (adenosine) stimuli by intravascular Doppler flow-wire. Epicardial diameter changes were evaluated by quantitative coronary angiography. Endomyocardial inducible (iNOS) and endothelial constitutive nitric oxide synthase were determined by RT-PCR. Nitric oxide production (nitrite and nitrate (NOx)) and TNF-alpha were measured in plasma samples from the aorta and coronary sinus.

RESULTS

CFVR was impaired in 26.1% (n=11) of patients at 1 month and in 31% (n=13) 12 months after HTx. iNOS-mRNA levels were significantly higher in patients with impaired endothelium-dependent CFVR. In addition, only in these patients were TNF-alpha levels higher and these correlated with plasma NOx levels at 1 and 12 months post-HTx (1 month: r=0.81, P=0.001; 12 months: r=0.62, P=0.04).

CONCLUSIONS

Coronary microcirculatory dysfunction in response to acetylcholine is present in nearly 30% of patients during the first year following transplantation. These patients present with higher iNOS-mRNA expression and TNF-alpha plasma levels. Selective modulation of the TNF-alpha/iNOS-pathway may be of therapeutic value to improve coronary endothelial dysfunction in cardiac transplant recipients.

[Megabacteria-associated proventriculitis in poultry in the state of Brandenburg, Germany]

During the second half of the year 2000, we have diagnosed a megabacterial-associated proventriculitis in 13 laying hens and 4 cocks from 14 different flocks and one turkey. All birds were submitted for necropsy because of progressive runting, increased mortality and poor laying performance in the herds. Routine diagnostic workup included necropsy, histology, bacteriology, parasitology and virology. At necropsy, the proventricular of the birds were enlarged. The walls were thickened and the mucosa covered with cloudy, grey-white mucus. Petechial haemorrhages and ulcerations predominantly at the proventricular-ventricular junction and sloughing of the necrotic koilin layer of the ventriculus were inconsistently present. Megabacteria (approximately 40-50 by 2-4 microns, gram-positive to gram-labile, rod-shaped organisms) were present in large numbers in touch preparations of the proventricular mucosal surface. In some of the preparations, the megabacteria showed a branching pattern similar to fungal hyphae. By histopathology, all birds showed moderate to marked, diffuse lympho-plasmacytic proventriculitis. Heterophilic exudation was present in the terminal portion of the proventriculus, where the greatest numbers of the organism were found. Megabacteria were present in the mucus covering the mucosal surface and the lumina of the superficial proventricular crypts, occasionally invading the luminal epithelium. Megabacterial infection was in general associated with other diseases such as avian tuberculosis, salmonellosis, coccidiosis, chlamydiosis and various other bacterial and parasitic infections. Only in one hen no other concurrent infectious organism was detected. The turkey had histomoniasis. Wild birds were regarded as probable source of infection, since all affected birds were kept under conditions allowing contact to wild birds and we have diagnosed megabacterial infections in wild-living green finches earlier.

3D-video- and robot-assisted minimally invasive ASD closure using the Port-Access techniques

BACKGROUND

Video-assisted minimally invasive surgical methods with endovascular-based femoral cardiopulmonary bypass (CPB) and balloon occlusion of the aorta (Port-Access technique) were used to close an ostium-secundum atrial septal defect (ASD) in 7 patients.

METHODS

Minor modifications were made to the system to provide drainage of the superior vena cava. The surgery was performed through a small (3.5-5cm) right anterolateral thoracotomy with 3D video and robotic arm assistance.

RESULTS

The operative procedures were completely uneventful and the patients were discharged four days postoperatively in good condition and with excellent cosmesis.

CONCLUSION

Using the modifications described, the Port-Access surgical method can be recommended for minimally invasive closure of an ASD.

Isolation and characterisation of five neurotoxic and cardiotoxic polypeptides from the sea anemone Anthopleura elegantissima

Five toxins (APE 1 to APE 5) of the sea anemone species Anthopleura elegantissima (Brandt) have been isolated from a toxic by-product fraction of its concentrated crude watery-methanolic extract, prepared previously for the isolation of a neuropeptide (the head-activator) by Schaller and Bodenmüller (Proc. Natl. Acad. Sci. USA 78 (1981) 7000) from 200kg sea anemones. Toxin purification was performed by desalting of the starting material by dialysis (MWCO 3500) against distilled water, anion exchange chromatography on QAE-Sephadex A25 at pH 8, twice gel filtration on Sephadex G50 m, repeated chromatography on QAE-Sephadex at pH 10 and chromatography on the cation exchanger Fractogel EMD SO(3)(-)-650 M.Final purification of the toxins was achieved by HPLC on MN SP 250/10 Nucleosil 500-5 C(18) PPN and MN SP 250/21 Nucleosil 300-7 C(18). Each toxin was composed of at least two isotoxins of which APE 1-1, APE 1-2, APE 2-1, APE 2-2 and APE 5-3 were isolated in preparative scale. With exception of APE 5-3 the sequences of the isotoxins have been elucidated. They resemble the 47 residue type-I long polypeptide toxins native to Anemonia sulcata (Pennant). All isotoxins paralyse the shore crab (Carcinus maenas) by tetanic contractions after i.m. application. The toxins modify current passing through the fast Na(+) channel in neuroblastoma cells, leading to delayed and incomplete inactivation. APE 1-1, APE 2-1 and APE 5-3 produce a positive inotropic effect in mammalian heart muscle, although they differ in potency. The order of potency is APE 2-1>APE 1-1>APE 5-3 (i.e. threshold concentrations are 1, 10 and 300nM, respectively). In addition, they enhance the spontaneous beating frequency in isolated right atria (guinea pig). The most potent cardiotoxic isotoxin is APE 2-1, its sequence is identical with that of AP-C, a toxin isolated and characterised previously by Norton et al. (Drugs and Foods from the Sea, 1978, University of Oklahoma Press, p. 37-50).LD50 APE 2-1:1 micro g/kg b.w. C. maenas (i.m.). LD50 APE 1-1:10 microg/kg b.w. C. maenas (i. m.). LD50 APE 5-3:50 microg/kg b.w. C. maenas (i.m.).

Mitotic degradation of cyclin A is mediated by multiple and novel destruction signals

Exit from mitosis requires Cdk1 inactivation, with the most prominent mechanism of Cdk1 inactivation being proteolysis of mitotic cyclins [1]. In higher eukaryotes this involves sequential destruction of A- and B-type cyclins. CycA is destroyed first, and CycA/Cdk1 inactivation is required for the metaphase-to-anaphase transition [2]. The degradation of CycA is delayed in response to DNA damage but is not prevented when the spindle checkpoint is activated [3, 4]. Cyclin destruction is thought to be mediated by a conserved motif, the destruction box (D box). Like B-type cyclins, A-type cyclins contain putative destruction box sequences in their N termini [5]. However, no detailed in vivo analysis of the sequence requirements for CycA destruction has been described so far. Here we tested several mutations in the CycA coding region for destruction in Drosophila embryos. We show that D box sequences are not essential for mitotic destruction of CycA. Destruction is mediated by at least three different elements that act in an overlapping fashion to mediate its mitotic degradation.

Comparing representations of the environmental spatial scale of organic chemicals

Long-range transport potential is one of the criteria proposed to identify chemicals as persistent organic pollutants. Here, different approaches to determine the spatial scale of an environmental area or region that can be impacted by an emitted chemical are investigated. A ranking of chemicals according to the spatial range R on a limited scale, as suggested by Scheringer, is equivalent to the characteristic travel distance L according to Bennett et al. on a linear, open scale. However, the methods are different with respect to the weighting of differences between the chemicals and according to their comparability with persistence. The characteristic travel distance L and the overall persistence are both plotted on open log-linear scales, whereas the spatial range R is represented on a limited scale. Various approaches of how to account for the mode of entry of chemicals are compared, and it is argued that relative measures are more appropriate to describe the long-range transport potential of chemicals than absolute numbers.

Risk of endotoxemia during the initial phase of gut decontamination with antimicrobial agents

Decontamination of the digestive tract with antimicrobial agents has been used for prevention and therapy of bacterial translocation. With regard to the well-described endotoxin-releasing properties of these agents, the question arises as to whether their enteral administration might result in an increased amount of intestinal endotoxins entering the circulation. Immunocompromised Wistar rats were intraduodenally challenged with live E. coli. Control animals received saline solution, decontaminated rats were treated with either tobramycin plus polymyxin B or ciprofloxacin alone through the duodenal tube. Plasma endotoxin activity and blood bacteria count were measured hourly over an observation period of 5 h. The intestinal bacterial count was determined at the end of the experiment. Gut decontamination in both groups receiving antimicrobial agents resulted in elevated plasma endotoxin levels compared with nondecontaminated controls. Maximum endotoxin levels were found to be 5-6 times higher in the ciprofloxacin group than in the control group and 2 times higher than in the tobramycin/polymyxin group. No positive blood cultures were detected. Intestinal bacterial count was similar in both treatment groups. Enterally applied antimicrobial agents bear an elevated risk of endotoxemia during the initial phase of gut decontamination. The amount of endotoxin translocating from the digestive tract to the circulation varies with the agents used. Polymyxin only partially reduced the observed endotoxin leakage from the gut.

The inositol 5-phosphatase SHIP is expressed as 145 and 135 kDa proteins in blood and bone marrow cells in vivo, whereas carboxyl-truncated forms of SHIP are generated by proteolytic cleavage in vitro

The inositol polyphosphate 5-phosphatase SHIP plays an important role in negative signalling in B cells and mast cells and in the down-regulation of cytokine receptor-mediated signals in myeloid cells. SHIP is expressed as a 145 kDa full-length protein and an isoform of 135 kDa due to alternative splicing. Additional smaller forms of SHIP which are truncated at the carboxy terminus have been described in bone marrow and peripheral blood mononuclear cells (PBMC). Our data demonstrate that human bone marrow cells and PBMC from healthy donors and patients with acute myeloid leukemia express the 145 kDa form of SHIP and low amounts of a 135 kDa form of SHIP in vivo whereas C-terminal-truncated SHIP proteins are generated by a PMSF-sensitive protease during the preparation of cell lysates in vitro. We have further characterized this protease and identified a proteolytic cleavage site in the human SHIP protein C-terminal to tryptophan residue 941. These data support a physiological role for the 145 and 135 kDa forms of SHIP in bone marrow and peripheral blood cells from normal donors and patients with acute myeloid leukemia.

[Acute thrombosis of pelvic and leg veins in agenesis of the renal segment of the inferior vena cava]

A 19-year-old, otherwise asymptomatic man presented to the hospital of orthopaedic surgery with acute severe pain like lumbago. Symptomatic treatment was performed after extensive orthopaedic diagnostic procedures. On the third day after admission he showed clinical signs of deep vein thrombosis with painful swelling and livid discoloration of both legs. Colour duplex ultrasound revealed complete thrombosis of the leg and pelvic veins bilaterally, but the cranial extent was not clear. Contrast-enhanced helical computer tomography of the abdomen and the pelvis confirmed deep pelvic vein thrombosis and showed extension into the inferior vena cava. Moreover, the study revealed the agenesis of the renal segment of the inferior vena cava with collateral flow through dilated lumbar veins to enlarged azygous and hemiazygous, through vertebral and paravertebral venous plexus. The renals were drained via dilated capsular veins. The agenesis of renal vena cava is a very rare anomaly causing acute thrombosis of the deep leg and pelvic veins. Other risk factors of thromboembolic disease were not found. The patient was treated successfully with systemic thrombolysis. Therefore we used ultra-high streptokinase infusion (9 million units over 6 hours). Colour duplex ultrasound revealed good flow into deep leg and pelvic veins after three cycle of lysis. Magnetic resonance angiography of the abdomen and pelvis was performed to evaluate the successful fibrinolysis with complete recanalisation of the pelvic veins and to demonstrate the venous anatomy. Permanent oral anticoagulation with phenprocoumon is indicated to decrease the high rate of recurrent thrombosis. Compression stockings were prescribed. To prevent thrombosis, additional risk factors like smoking, immobilization and unusual physical activity should be strictly avoided.

Coronary vasomotor dysfunction in the cardiac allograft: impact of different immunosuppressive regimens

Immunosuppression may have an important impact on early graft coronary endothelial injury. We investigated functional and morphologic coronary alterations, myocardial expression, and cardiac release of possible mediators of allograft vasculopathy within 6 months after cardiac transplantation with respect to different immunosuppressive regimens. Epicardial and microvascular endothelium-dependent and endothelium-independent vasomotor function and epicardial intimal thickening were measured in 8 transplant recipients treated with cyclosporin A (CyA), azathioprine, and prednisone (group 1), 9 transplant recipients treated with tacrolimus (TKL), azathioprine, and prednisone (group 2), and 14 patients treated with TKL, mycophenolate mofetil (MMF), and prednisone (group 3). The gene expressions of inducible and endothelial nitric oxide synthase (iNOS and eNOS), endothelin-1, prostacyclinsynthase, and thromboxansynthase were analyzed in endomyocardial biopsy specimens using semiquantitative reverse transcription polymerase chain reaction. Transcardiac cytokine release, endothelin-1, and nitrate-release were determined from plasma samples. Epicardial endothelial dysfunction (vasoconstriction to acetylcholine > 10%) and microvascular smooth muscle cell dysfunction (flow velocity increase to adenosine and nifedipine < 2.0) were enhanced in heart transplant recipients immunosuppressed with TKL, azathioprine, and prednisone. The prevalence of epicardial dysfunction was 78% in group 2 versus 44% and 46% in group 1 and 3 (p < 0.05), respectively. The prevalence of microvascular dysfunction was 56% in group 2 versus 13% and 7% in group 1 and 3 (p < 0.02), respectively. Coronary vasomotor dysfunction was associated with increased myocardial iNOS expression (p < 0.05), decreased eNOS expression (p < 0.05), and enhanced cardiac immunoreactive interleukin-6 (p < 0.01). Coronary intimal thickening was not different between the groups. The combination of TKL and MMF appears to be superior to TKL and azathioprine (and comparable to CyA and azathioprine) concerning preservation of early coronary vasomotor function, eNOS expression, iNOS suppression as well as cardiac interleukin-6 release. This may have an important impact on subsequent development of transplant coronary atherosclerosis.

Reduced expression of systemic proinflammatory cytokines after off-pump versus conventional coronary artery bypass grafting

BACKGROUND

Both cardiopulmonary bypass (CPB) and operative trauma are associated with increased expression of proinflammatory cytokines. We assessed the relative contribution of CPB on activation of various proinflammatory cytokines in patients undergoing coronary revascularization by comparing them with patients receiving coronary artery bypass grafts using off-pump (OPCAB) techniques.

METHODS

Twenty-six patients were assigned to either the OPCAB procedure using a suction device and regular sternotomy (n = 13) or were treated conventionally using extracorporeal circulation, blood cardioplegia and hypothermic arrest (29-31 degrees C; n = 13). C-reactive protein and systemic levels of TNF-alpha, TNF specific receptors Rp1 and Rp2, Interleukin-6 (IL-6) and soluble IL-2 receptors (sIL-2r) were assayed by ELISA or EIA. To account for systemic nitric oxide production, total nitrate/nitrite (NOx) was measured using the Griess reaction.

RESULTS

Coronary revascularization with CPB was associated with a significant expression increase in the TNF-system and sIL-2r when compared to the OPCAB patients. Although IL-6 expression did not differ between both groups, C-reactive protein levels were significantly lower in the OPCAB group. Moreover, systemic NOx levels as the stable end-product of nitric oxide were lower in the OPCAB group.

CONCLUSIONS

The data of the present study indicate that, despite comparable surgical trauma, the OPCAB revascularization procedure without the use of CPB and cardioplegic arrest significantly reduces the systemic inflammatory response syndrome and early catecholamine requirement. This may contribute to improved organ function, subsequently resulting in improved postoperative recovery from surgical revascularization procedures, particularly in critically ill patients.

Reduced myocardial cellular damage and lipid peroxidation in off-pump versus conventional coronary artery bypass grafting

BACKGROUND

The development of new surgical devices and techniques allows off pump coronary artery bypass grafting (OPCAB) without the use of CPB and cardioplegia. This study tested whether OPCAB reduces myocardial cell damage, lipid peroxidation and systemic endothelin release when compared to conventional coronary artery bypass grafting.

METHODS

Twenty-six patients were assigned to either the OPCAB procedure using a suction device and regular sternotomy (n = 13) or were treated conventionally using extracorporeal circulation, blood cardioplegia and hypothermic arrest (29-31 degrees C; n = 13). Troponin I and creatine kinase - MB were determined for cardiac specific cell damage. Myocardial and systemic malondialdhyde levels were measured to account for oxyradical mediated lipid peroxidation. Systemic big-endothelin levels were determined as a marker for endothelial cell activation.

RESULTS

A significant reduction of the cardiac specific cell damage was observed in the OPCAB group vs. the CABG group over time in the absence of acute myocardial ischemia or infarction. In addition, systemic and myocardial lipid peroxidation as measured by the malondialdehyde (MDA) levels were lower in the OPCAB group when compared to CABG. Finally, plasma levels of big-Endothelin (big-ET) significantly rose in the CABG but not in the OPCAB group.

CONCLUSIONS

The data of the present study indicate that OPCAB revascularization without the use of CPB and cardioplegic arrest reduces myocardial cell damage and lipid peroxidation. It is also associated with a reduced activation of the potent vasoconstrictor peptide endothelin. All of this may contribute to improved myocardial function and faster postoperative recovery from surgical revascularization procedures, particularly in critically ill patients.

Three-dimensional video and robot-assisted port-access mitral valve operation

BACKGROUND

In order to minimize surgical trauma, video-assisted mitral valve operation has been started using the Port-Access technique with the addition of a three-dimensional visualization system (Vista Cardiothoracic Systems Inc, Westborough, MA) and a voice-controlled camera-holding robotic arm (Aesop; Computer Motion Inc, Goleta, CA).

METHODS

Port-Access mitral valve replacement or repair (PAMVR) was undertaken using an endovascular cardiopulmonary bypass (CPB) system. Fifty patients underwent Port-Access mitral valve replacement or repair. A three-dimensional thoracoscope was inserted allowing complete three-dimensional projection of the mitral valve (Vista). In the last 20 patients, the camera was attached to a robotic arm (Aesop), which allowed stabilization and voice-activated movement of the camera. Mitral valve repair was performed in 26 patients, and the valve was replaced in 24 patients with a mechanical valve prosthesis.

RESULTS

Median time of operation was 4.2 hours, aortic cross-clamp time 83 minutes, CPB time 125 minutes, intensive care unit stay 1.5 days and hospitalization 9.0 days. Three months follow-up was complete in 40 patients, with 34 patients (85%) in New York Heart Association class I and 6 patients in class II. Mortality was 0% and rate of reoperation was 2%, with a follow-up time up to 1.5 years postoperatively.

CONCLUSIONS

Using three-dimensional video and robotic assistance, it was possible to minimize the length of skin incision, but at the same time to optimally visualize the whole mitral valve apparatus in order to perform true Port-Access mitral valve operation, including various repair techniques.

Extrahepatic biliary atresia in a border collie

Progressive lameness and leg pain were the predominant clinical signs in a 17-week-old male border collie presented for examination. On clinical investigation, extrahepatic cholestasis in association with rickets due to inadequate vitamin D resorption was diagnosed. The dog was treated parenterally with vitamin D and a cholecystoduodenostomy was performed. At 25 days postsurgery the lameness had resolved and bone structure was radiographically normal. However, at six weeks postsurgery, the dog's condition deteriorated rapidly and euthanasia was finally performed at eight weeks postsurgery. At postmortem examination, Toxocara canis nematodes were found to have invaded the biliary system via the anastomosis between the gallbladder and duodenum, causing biliary and hepatic toxocariasis. The cause of the primary extrahepatic cholestasis was atresia of the common bile duct at the hepatic end. The liver tissue showed microscopic lesions of chronic extrahepatic cholestasis as well as acute inflammation associated with the nematode invasion. There was no postmortem evidence of bone lesions. Extrahepatic biliary atresia is extremely rare in animals and has not been described before in dogs. In contrast, it represents the most common cause of congenital cholestasis in children, occurring in approximately one per 10,000 to 15,000 live births.

Modulation of coronary vasomotor tone by cytokines in cardiac transplant recipients

BACKGROUND

Upon exposure to cytokines, endothelial cells may undergo profound alterations of vasomotor function. In this study, we characterized the relationship between coronary epicardial and microvascular vasomotor function and expression of specific cytokine patterns in human heart transplant recipients.

METHODS

We studied 49 cardiac transplant recipients, without acute rejection or infection at an average of 6+/-3 months after transplantation. Coronary resistance vessel function was measured in an endothelium-dependent manner with acetylcholine (5 and 150 microg/5 min; intracoronary injection) and in an endothelium-independent manner with adenosine (400 and 800 microg/5 min; intracoronary injection) using an intracoronary Doppler flow wire. Simultaneous epicardial diameter changes were measured using quantitative coronary angiography. Coronary sinus and aortic serum levels of soluble interleukin (IL)-2 receptor and soluble tumor necrosis factor-a receptors (sTNF-R1 and sTNF-R2), TNF-alpha, and IL-6 were determined. Transcardiac cytokine release (coronary sinus minus aortic levels) was correlated with coronary vasomotor function.

RESULTS

The highest amounts of cardiac cytokine release were observed for IL-6 (32+/-14% increase) and sTNF-R1 (26+/-13% increase). A significant inverse correlation between microvascular endothelial function and cardiac release of soluble IL-2 receptor (P=0.04) and IL-6 (P=0.03) was detected, whereas a positive correlation was observed to sTNF-R1 (P=0.004). Distal epicardial endothelial vasomotion was inversely correlated to transcardiac sTNF-R2 release (P=0.03).

CONCLUSIONS

Cytokine production and activation, a common phenomenon early after heart transplantation, is related at least in part to endothelial vasomotor dysfunction of the epicardial and microvascular compartment. These results support the hypothesis that coronary endothelial dysfunction after cardiac transplantation is an immunologic phenomenon. Since endothelial dysfunction seems to be a crucial step in the pathogenesis of cardiac allograft vasculopathy, coronary cytokine suppression should be a therapeutic target of improved future immunosuppressive regimens.

Endothelin in coronary endothelial dysfunction early after human heart transplantation

BACKGROUND

Cytokines and growth factors released as part of the immune response to alloantigenic stimuli are capable of regulating endothelin-1 expression in the allograft. Endothelin plays a significant role as a modulator of coronary vascular reactivity in the early stages of atherosclerosis and may be important as a participant in and marker for cardiac allograft vasculopathy.

METHODS

We characterized a possible relationship between morphological and functional coronary changes, transcardiac plasma endothelin level and myocardial endothelin-mRNA expression in 33 cardiac transplant recipients in the early, stable phase 5+/-3 months after orthotopic heart transplantation. Coronary microvascular function was determined as endothelium-dependent with acetylcholine and endothelium-independent with adenosine using intracoronary Doppler-FloWire. The percentage of the epicardial diameter changes was measured using quantitative coronary angiography. Intravascular ultrasound was performed to quantify intimal hyperplasia. Cardiac endothelin uptake or release was determined by measuring plasma endothelin levels in the coronary sinus and aorta. Myocardial endothelin-gene expression was determined using semiquantitative RT-PCR.

RESULTS

The aortic endothelin levels were significantly increased in transplant recipients compared to nontransplanted patients (11.8+/-2.2 vs 7.2+/-0.9 fmol/mL; P < 0.001). Endothelin uptake was noticed in the majority of patients, and the amount of endothelin uptake was correlated to microvascular (r = 0.37; P < 0.05) and epicardial (r = 0.41; P < 0.03) endothelium-dependent vasodilatation. High mRNA signal intensity was associated with significantly reduced coronary flow response to acetylcholine compared to patients with low myocardial gene expression (coronary flow reserve 2.4+/-0.9 vs 3.4+/-0.8, respectively; P < 0.005). Morphological coronary changes early after transplantation were not correlated to endothelin plasma levels or myocardial gene expression.

CONCLUSION

Coronary endothelial vasomotor dysfunction after cardiac transplantation is associated with an increased myocardial endothelin mRNA expression and decreased endothelin-uptake by the heart. We postulate that early activation in the endothelin system may have a pivotal role in the acceleration of the atherosclerotic process in transplant patients.

Inducible nitric oxide synthase activation after ischemia/reperfusion contributes to myocardial dysfunction and extent of infarct size in rabbits: evidence for a late phase of nitric oxide-mediated reperfusion injury

BACKGROUND

Ischemia/reperfusion (I/R) leads to the induction of inducible nitric oxide synthase. The present study investigated the effects of selective and continuous inhibition of iNOS on myocardial performance, infarct size and histomorphological changes after I/R in rabbits.

METHODS AND RESULTS

Ischemia/reperfusion (I/R) was induced by occlusion of the circumflex coronary artery for 30 min followed by 48 h of reperfusion. Sham animals (group A) served as control. Three groups were subjected to I/R: (B) placebo; (C) aminoguanidine (AMG; 10 mg/kg bolus) given prior to and 48 h after I/R to test its acute effects; (D) AMG (300 mg/kg/day s.c.) to test effects of continuous treatment. Hemodynamics, myocardial blood flow, infarct size, iNOS activity, cGMP levels, immunohistochemical analysis of iNOS expression and AMG tissue levels were determined. Continuous AMG treatment improved myocardial performance (hemodynamics and blood flow) compared to placebo group. iNOS was highest in placebo-treated animals. AMG tissue levels were highest in tissues affected by I/R. Infarct size (% of the circumflex region) was significantly smaller in group D when compared to group B.

CONCLUSIONS

This is the first study showing that activation of myocardial iNOS isozyme during 48 h of reperfusion contributes to a late phase of I/R-induced injury in rabbits. Selective and continuous modulation of iNOS by AMG over this time period exerts protective effects with respect to myocardial performance, coronary blood flow, cellular infiltration and reduction of infarct size; this may be a novel therapeutic approach in the clinical situation to limit irreversible myocardial injury associated with ischemia and reperfusion.

Aminoguanidine inhibits inducible NOS and reverses cardiac dysfunction late after ischemia and reperfusion--implications for iNOS-mediated myocardial stunning

BACKGROUND

The functional significance of inducible nitric oxide synthase (iNOS) activation in response to myocardial ischemia and reperfusion (I/R) was investigated.

METHODS

New Zealand rabbits were randomly treated with either placebo, aminoguanidine (AMG; selective iNOS inhibitor), or L-arginine. Left-ventricular hemodynamics and myocardial blood flow were measured before coronary occlusion and 30 minutes and 48 h after initiation of reperfusion.

RESULTS

I/R resulted in left-ventricular dysfunction and increased myocardial iNOS activity. Placebo treatment had no effects on myocardial function. However, AMG significantly inhibited iNOS activity, significantly improved left-ventricular maximum + dP/dt and decreased LVEDP, whereas administration of L-arginine reduced + dP/dt and slightly increased LVEDP, compared to AMG-treated animals. Myocardial blood flow in the affected myocardium significantly increased after both AMG and L-arginine.

CONCLUSIONS

The present data indicate that induction of myocardial iNOS after 48 h I/R contributes to the development of reversible left-ventricular dysfunction, suggesting the involvement of iNOS in myocardial stunning. Whereas L-arginine is associated with further reduction of left-ventricular contractility, continuous inhibition of iNOS activation by AMG improves left-ventricular performance; this may be a novel and clinically important therapeutic modality in certain disease states associated with I/R, including cardiac operations using extracorporeal circulation and coronary angioplastic procedures.