Determination of Decoquinate in Animal Feeds by Liquid Chromatography: Collaborative Study

The performance characteristics of a liquid chromatographic (LC) method for the analysis of decoquinate (DEC) in supplements, premixes, and complete animal feeds at medicating and trace levels were collaboratively studied. DEC is extracted from ground feed samples with 1 calcium chloridemethanol solution using mechanical agitation for 90 min. After centrifugation for 5 min and dilution (if necessary), an aliquot of the extract is diluted with water. The diluted extracts are filtered and analyzed by reversed-phase LC with fluorescence detection. Suspect positive trace-level samples are confirmed by using an alternate excitation wavelength. Fourteen test samples of medicated feeds, supplement, and medicated premix, along with 8 test samples for trace-level analysis, were sent to 13 collaborators (one in Canada, 4 in Europe, and 8 in the United States). Test samples were analyzed as blind duplicates. Acceptable results were received from 12 laboratories for the medicated test samples and from 13 laboratories for the trace-level samples. Repeatability relative standard deviation estimates ranged from 1.3 to 5.6. Reproducibility relative standard deviations estimates ranged from 2.8 to 6.1, and HorRat values ranged from 0.22 to 0.74.

Updates to the Canadian Immunization Guide: April 2015 to October 2016

The Canadian Immunization Guide (CIG) is a trusted, reader-friendly summary of information and advice on immunization that has been used by health care providers and policy makers for decades. It is continuously updated based on new recommendations from the National Advisory Committee on Immunization (NACI) and the Committee to Advise on Tropical Medicine and Travel (CATMAT), two external advisory bodies to the Public Health Agency of Canada. In September 2016, the CIG moved to a new web platform that has improved navigability and is more mobile friendly. Between April 2015 and October 2016, five new NACI statements were published and are reflected in the CIG. The objective of this article is to provide readers with highlights of recent key changes to active vaccine recommendations in the CIG. For example, for Hepatitis (HA) vaccine, it may now be administered to persons six months of age and older and considered for all individuals receiving repeated replacement of plasma-derived clotting factors. There are now new recommendations for the use of HA immunoglobulin post-exposure prophylaxis. For Human papillomavirus (HPV) vaccine, any of the authorized HPV vaccines in Canada, including HPV9 vaccine, can be used according to the recommended HPV immunization schedules. For influenza vaccine, adults with neurologic or neurodevelopment conditions have been added to the group for whom influenza vaccination is particularly recommended, high-dose influenza vaccine has been approved for use in Canada in adults ≥65 years of age and live attenuated influenza vaccine (LAIV) is no longer a preferentially recommended product for use in children and adolescents. On an individual basis, pneumococcal conjugate 13-valent (PNEU-C-13) vaccine may be recommended to immunocompetent adults aged 65 years and older if not previously immunized against pneumococcal disease. When it is given, it should precede the pneumococcal polysaccharide 23-valent (PNEU-P-23) vaccine. Varicella immune globulin may now be administered up to 10 days since last exposure for the purpose of disease attenuation and there were a number of minor changes to the criteria for assessing varicella immunity.

Impaired stimulation of glucose transport in cardiac myocytes exposed to very low-density lipoproteins

We recently observed that free fatty acids impair the stimulation of glucose transport into cardiomyocytes in response to either insulin or metabolic stress. In vivo, fatty acids for the myocardium are mostly obtained from triglyceride-rich lipoproteins (chylomicrons and Very Low-Density Lipoproteins). We therefore determined whether exposure of cardiac myocytes to VLDL resulted in impaired basal and stimulated glucose transport. Primary adult rat cardiac myocytes were chronically exposed to VLDL before glucose uptake was measured in response to insulin or metabolic stress, provoked by the mitochondrial ATP synthase inhibitor oligomycin. Exposure of cardiac myocytes to VLDL reduced both insulin-and oligomycin-stimulated glucose uptake. The reduction of glucose uptake was associated with a moderately reduced tyrosine phosphorylation of the insulin receptor. No reduction of the phosphorylation of the downstream effectors of insulin signaling Akt and AS160 was however observed. Similarly only a modest reduction of the activating phosphorylation of the AMP-activated kinase (AMPK) was observed in response to oligomycin. Similar to our previous observations with free fatty acids, inhibition of fatty acid oxidation restored oligomycin-stimulated glucose uptake. In conclusions, VLDL-derived fatty acids impair stimulated glucose transport in cardiac myocytes by a mechanism that seems to be mediated by a fatty acid oxidation intermediate. Thus, in the clinical context of the metabolic syndrome high VLDL may contribute to enhancement of ischemic injury by reduction of metabolic stress-stimulated glucose uptake.

Pipette aspiration applied to the characterization of nonhomogeneous, transversely isotropic materials used for vocal fold modeling

The etiology and treatment of voice disorders are still not completely understood. Since the vibratory characteristics of vocal folds are strongly influenced by both anatomy and mechanical material properties, measurement methods to analyze the material behavior of vocal fold tissue are required. Due to the limited life time of real tissue in the laboratory, synthetic models are often used to study vocal fold vibrations. In this paper we focus on two topics related to synthetic and real vocal fold materials. First, because certain tissues within the human vocal folds are transversely isotropic, a fabrication process for introducing this characteristic in commonly used vocal fold modeling materials is presented. Second, the pipette aspiration technique is applied to the characterization of these materials. By measuring the displacement profiles of stretched specimens that exhibit varying degrees of transverse isotropy, it is shown that local anisotropy can be quantified using a parameter describing the deviation from an axisymmetric profile. The potential for this technique to characterize homogeneous, anisotropic materials, including soft biological tissues such as those found in the human vocal folds, is supplemented by a computational study.

[What is new in the medical management of acute heart failure?]

Acute heart failure (AHF) is a frequent medical condition associated with a poor prognosis. Based on systolic blood pressure at presentation, patients with AHF can be classified into 5 clinical profiles enabling a more targeted use of standard medications including diuretics, vasodilators and inotropes. The most recent guidelines underline the importance of a rapid management and the favorable impact of heart failure programs, which reduce morbidity and mortality after an admission for AHF. New therapeutic perspectives include ultrafiltration, vasopressin and adenosine antagonists, relaxin and new inotropes such as istaroxime.

[Paravalvular leak following surgical valve replacement: is there a role for percutaneous paravalvular leak reduction?]

After valve replacement, significant paravalvular leaks (PVL) may develop in up to 12.5% of the cases. Signs and symptoms include congestive heart failure and/or haemolysis and therefore may require reintervention. Redo valve surgery is considered the therapy of choice for symptomatic patients, either by valve replacement or leak repair. Considering the risk of morbidity and mortality associated with a surgical reintervention and the high post-surgical recurrence of PVL, the endovascular treatment represents an attractive alternative to surgery for high risk patients. The percutaneous approach aims at PVL reduction by implantation of certain occluder devices. The procedure is technically feasible in 60 to 90% of the cases according to different series. Technical success is associated with clinical improvement in 50 to 80% of the cases.

Measurement of the elasticity modulus of soft tissues

A measurement setup combined with a Finite Element (FE) simulation is presented to determine the elasticity modulus of soft materials as a function of frequency. The longterm goal of this work is to measure in vitro the elasticity modulus of human vocal folds over a frequency range that coincides with the range of human phonation. The results will assist numerical simulations modeling the phonation process by providing correct material parameters. Furthermore, the measurements are locally applied, enabling to determine spatial differences along the surface of the material. In this work the method will be presented and validated by applying it to silicones with similar characteristics as human vocal folds. Three silicone samples with different consistency were tested over a frequency range of 20-250 Hz. The results of the pipette aspiration method revealed a strong frequency dependency of the elasticity modulus, especially below 100 Hz. In this frequency range the elasticity moduli of the samples varied between 5 and 27 kPa.

Mitral tendon prolapsing into the left ventricular outflow tract

Intracardiac masses of the mitral valve are rare. Their differential diagnosis is wide, ranging from tumors (myxomas, lipomas and fibroelastomas), thrombi and abnormal muscular or fibrous bands. We report a case and management. A 68 year-old asymptomatic female who had undergone coronary angioplasty and stent placement in the left anterior descending artery for acute myocardial infarction four years earlier, was shown to have, on routine follow-up, an intracardiac mass originating from the anterior leaflet of the mitral valve and prolapsing into the left ventricular outflow tract (LVOT). The patient underwent surgical excision of the mass under cardiopulmonary bypass, to prevent cerebral or coronary embolization and sudden death due to the highly sensitive location of the mass, in the high-velocity flow LVOT. A transverse aortotomy provided exposure of the ventricular surface of the anterior mitral leaflet and revealed a fusiform mass attached to the medial segment of the anterior leaflet, resembling a secondary cordae, measuring 20 by 3 mm. The implantation was calcified on the ventricular aspect of the anterior mitral leaflet. This mass was completely excised. Postoperative recovery was uneventful. Peroperative and postoperative transesophageal echocardiography were normal. Histological examination showed a partially necrosed and calcified fibrous tissue lined by endothelium. The final diagnosis was that of a mitral tendon. Intracardiac masses of the mitral valve are rare lesions, mostly papillary fibroelastomas and myxomas and more rarely mitral tendons, which require surgical resection for prevention of embolization. The definitive diagnosis is often only obtained on histological analysis.

[The contribution of molecular genetics to clinical cardiology: the example of hypertrophic cardiomyopathy]

Recent advances in molecular genetics have resulted in the identification of pathogenic mutations in a number of genes which cause hypertrophic cardiomyopathy (HCM). In order to integrate this increasing genetic knowledge of HCM into the cardiology clinic, we offer all patients and their families diagnosis and genetic counselling based on these current data. In addition, within the framework of a multidisciplinary project between the Divisions of Medical Genetics, Cardiology and Pediatric Cardiology of the University Hospitals of Geneva, we have developed a resequencing array enabling rapid molecular diagnosis of HCM. Data from this study will enhance our understanding of the aetiology of HCM, and improve our knowledge of genotype-phenotype correlations. This information will enable us to develop new therapeutic and preventive concepts, with the aim of tailoring therapies to the specific genetic variant of each patient and its family.

Impaired glucose metabolism in the heart of obese Zucker rats after treatment with phorbol ester

OBJECTIVE

To investigate the influence of obesity on the regulation of myocardial glucose metabolism following protein kinase C (PKC) activation in obese (fa/fa) and lean (Fa/?) Zucker rats.

DESIGN

Isolated hearts obtained from 17-week-old lean and obese Zucker rats were perfused with 200 nM phorbol 12-myristate 13-acetate (PMA) for different time periods prior to the evaluation of PKC and GLUT-4 translocation. For metabolic studies isolated hearts from 48 h starved Zucker rats were perfused with an erythrocytes-enriched buffer containing increased concentrations (10-100 nM) of PMA.

MEASUREMENTS

Immunodetectable PKC isozymes and GLUT-4 were determined by Western blots. Glucose oxidation and glycolysis were evaluated by measuring the myocardial release of 14CO2 and 3H2O from [U-14C]glucose and [5-3H]glucose, respectively.

RESULTS

PMA (200 nM) induced maximal translocation of ventricular PKCalpha from the cytosol to the membranes within 10 min. This translocation was 2-fold lower in the heart from obese rats when compared to lean rats. PMA also induced a significant translocation of ventricular GLUT-4 from the microsomal to the sarcolemmal fraction within 60 min in lean but not in obese rats. Rates of basal cardiac glucose oxidation and glycolysis in obese rats were approximately 2-fold lower than those of lean rats. Perfusion with increasing concentrations of PMA (10-100 nM) led to a significant decrease of cardiac glucose oxidation in lean but not in obese rats.

CONCLUSION

Our results show that in the heart of the genetically obese Zucker rat, the impairment in PKCalpha activation is in line with a diminished activation of GLUT-4 as well as with the lack of PMA effect on glucose oxidation.

Postinfarction heart failure in rats is associated with upregulation of GLUT-1 and downregulation of genes of fatty acid metabolism

OBJECTIVES

Increasing evidence suggests that left ventricular remodeling is associated with a shift from fatty acid to glucose metabolism for energy production. The aim of this study was to determine whether left ventricular remodeling with and without late-onset heart failure after myocardial infarction is associated with regional changes in the expression of regulatory proteins of glucose or fatty acid metabolism.

METHODS

Myocardial infarction was induced in rats by ligation of the left anterior descending coronary artery (LAD). In infarcted and sham-operated hearts the peri-infarction region (5-mm zone surrounding the region at risk), the interventricular septum and the right ventricular free wall were separated for analysis.

RESULTS

At 8 and 20 weeks after LAD ligation, the peri-infarction region and the septum exhibited marked re-expression of atrial natriuretic factor [+252+/-37 and +1093+/-279%, respectively, in the septum (P<0.05)] and of alpha-smooth muscle actin [+34+/-10 and +43+/-14%, respectively, in the septum (P<0.05)]. At 8 weeks, when left ventricular hypertrophy was present without signs of heart failure, myocardial mRNA expression of glucose transporters (GLUT-1 and GLUT-4) was not altered, whereas mRNA expression of medium-chain acyl-CoA dehydrogenase (MCAD) was significantly reduced in the peri-infarction region (-25+/-7%; P<0.05). In hearts exhibiting heart failure 20 weeks after infarct-induction there was a change in all three ventricular regions of both mRNA and protein content of GLUT-1 [+72+/-28 and +121+/-15%, respectively, in the peri-infarction region (P<0.05)] and MCAD [-29+/-9 and -56+/-4%, respectively, in the peri-infarction region (P<0.05)].

CONCLUSION

In rats with large myocardial infarction, progression from compensated remodeling to overt heart failure is associated with upregulation of GLUT-1 and downregulation of MCAD in both the peri-infarction region and the septum.

Calcium-mediated activation of pyruvate dehydrogenase in severely injured postischemic myocardium

Indirect evidence suggests that activity of pyruvate dehydrogenase (PDH) influences recovery of the myocardium after transient ischemia. The present study examined the relationship between postischemic injury and activity of PDH and the role of mitochondrial calcium uptake for observed changes in PDH activity. Isovolumically beating isolated rat hearts perfused with erythrocyte-enriched buffer containing glucose, palmitate, and insulin were submitted to either 20 or 35 min of no-flow ischemia. After 20 min of no-flow ischemia, hearts exhibited complete recovery of developed left ventricular pressure (DLVP). The proportion of myocardial PDH in the active state was modestly increased to 38% (compared with 13% in control hearts) without a change in glucose oxidation. In contrast, in hearts subjected to 35 min of no-flow ischemia (which exhibited poor recovery of DLVP), there was marked stimulation of glucose oxidation (+460%; P < 0.01) and pronounced increase in the active fraction of PDH to 72% (P < 0.01). Glycolytic flux was not significantly altered. Ruthenium red (6 microM) completely abolished the activation of PDH and the increase in glucose oxidation. The results indicate that variable stimulation of glucose oxidation during reperfusion is related to different degrees of activation of PDH, which depends on the severity of the ischemic injury. Activation of PDH seems to be mediated by myocardial calcium uptake.

Finite element simulation of nonlinear wave propagation in thermoviscous fluids including dissipation

A recently developed finite element method (FEM) for the numerical simulation of nonlinear sound wave propagation in thermoviscous fluids is presented. Based on the nonlinear wave equation as derived by Kuznetsov, typical effects associated with nonlinear acoustics, such as generation of higher harmonics and dissipation resulting from the propagation of a finite amplitude wave through a thermoviscous medium, are covered. An efficient time-stepping algorithm based on a modification of the standard Newmark method is used for solving the non-linear semidiscrete equation system. The method is verified by comparison with the well-known Fubini and Fay solutions for plane wave problems, where good agreement is found. As a practical application, a high intensity focused ultrasound (HIFU) source is considered. Impedance simulations of the piezoelectric transducer and the complete HIFU source loaded with air and water are performed and compared with measured data. Measurements of radiated low and high amplitude pressure pulses are compared with corresponding simulation results. The obtained good agreement demonstrates validity and applicability of the nonlinear FEM.

Altered expression of proteins of metabolic regulation during remodeling of the left ventricle after myocardial infarction

Non-infarcted myocardium after coronary occlusion undergoes progressive morphological and functional changes. The purpose of this study was to determine whether non-infarcted myocardium exhibits (1) alteration of the substrate pattern of myocardial metabolism and (2) concomitant changes in the expression of regulatory proteins of glucose and fatty acid metabolism. Myocardial infarction was induced in rats by ligation of the left coronary artery. One day and eight weeks after coronary occlusion, glucose and palmitate oxidation were measured. Expression of selected proteins of metabolism were determined one day to 12 weeks after infarction. One day after coronary occlusion no difference of glucose and palmitate oxidation was detectable, whereas after eight weeks, glucose oxidation was increased (+84%, P<0.05) and palmitate oxidation did not change significantly (-19%, P=0.07) in infarct-containing hearts, compared with hearts from sham-operated rats. One day after coronary occlusion, myocardial mRNA expression of the glucose transporter GLUT-1 was increased (+86%, P<0.05) and the expression of GLUT-4 was decreased (-28%, P<0.05) in surviving myocardium of infarct-containing hearts. Protein level of GLUT-1 was increased (+81%, P<0.05) and that of GLUT-4 slightly, but not significantly, decreased (-16%, P=NS). mRNA expressions of heart fatty acid binding protein (H-FABP), and of medium chain acyl-CoA dehydrogenase (MCAD), were decreased by 36% (P<0.05) and 35% (P=0. 07), respectively. Eight weeks after acute infarction, the left ventricle was hypertrophied and, at this time-point, there was no difference in the expression of GLUT-1 and GLUT-4 between infarcted and sham-operated hearts. However, myocardial mRNA and protein content of MCAD were decreased by 30% (P<0.01) and 27% (P<0.05), respectively. In summary, in surviving myocardium, glucose oxidation was increased eight weeks after coronary occlusion. Concomitantly, mRNA and protein expression of MCAD were decreased, compatible with a role of altered expression of regulatory proteins of metabolism in post-infarction modification of myocardial metabolism.

Detection and quantification of valvular heart disease with dynamic cardiac MR imaging

Magnetic resonance (MR) imaging is rapidly gaining acceptance as an accurate, reproducible, noninvasive method for optimal assessment of structural and functional parameters in patients with valvular heart disease. The severity of valvular regurgitation can be evaluated with cine gradient-echo MR imaging, which allows measurement of the area of the signal void corresponding to the abnormal flow jet. Alternatively, this modality can be used to obtain ventricular volumetric measurements and calculate the regurgitant fraction, or velocity-encoded cine (VEC) MR imaging can be used to quantify regurgitant blood flow. The severity of valvular stenosis can be determined by evaluating the flow jet and associated findings with either modality or by using VEC MR imaging to calculate the transvalvular pressure gradient and valve area. Dynamic MR imaging allows accurate assessment of ventricular function and comprehensive evaluation of pathophysiologic changes. In addition, good interstudy reproducibility suggests a role for VEC MR imaging in assessing the effects of therapeutic intervention and monitoring regurgitant fraction, thereby helping in surgical planning and the prevention of ventricular dysfunction. With greater cost-effectiveness and the increasing availability of new hardware and more advanced techniques, MR imaging will become a routine procedure in valvular heart disease.

Postischemic recovery of heart metabolism and function: role of mitochondrial fatty acid transfer

Postischemic recovery of contractile function is better in hearts from fasted rats than in hearts from fed rats. In this study, we examined whether feeding-induced inhibition of palmitate oxidation at the level of carnitine palmitoyl transferase I is involved in the mechanism underlying impaired recovery of contractile function. Hearts isolated from fasted or fed rats were submitted to no-flow ischemia followed by reperfusion with buffer containing 8 mM glucose and either 0.4 mM palmitate or 0.8 mM octanoate. During reperfusion, oxidation of palmitate was higher after fasting than after feeding, whereas oxidation of octanoate was not influenced by the nutritional state. In the presence of palmitate, recovery of left ventricular developed pressure was better in hearts from fasted rats. Substitution of octanoate for palmitate during reperfusion enhanced recovery of left ventricular developed pressure in hearts from fed rats. However, the chain length of the fatty acid did not influence diastolic contracture. The results suggest that nutritional variation of mitochondrial fatty acid transfer may influence postischemic recovery of contractile function.

Ultrasonic characterization of liquids using resonance antireflection

This paper presents an ultrasonic method for measuring the density of liquids with a solid layer separating a reference fluid and a test fluid. By adjusting the frequency of the exciting signal according to the thickness of the layer, it is possible to generate destructive interference of the waves reflected at the first and at the second boundary of the layer. Thus, the layer appears to vanish for the incident waves. The resulting echo signal depends only on the acoustic impedances of the reference fluid and the test fluid and the density which is of interest can be extracted. Short and long-term drifts of the electronics and the ultrasonic transducer implied are eliminated by using the well-known pulse-echo technique with additional frontwave detection.

Time domain evaluation of resonance antireflection (RAR) signals for ultrasonic density measurement

This paper presents an ultrasonic method for measuring the mass density of liquids with a solid layer separating a reference fluid and a test fluid. By adjusting the frequency of the exciting signal according to the thickness of the layer, it is possible to generate destructive interference of the waves reflected at the first and second boundary of the layer. Thus, the layer appears to vanish for the incident waves. In the steady state the resulting echo signal depends only on the acoustic impedances of the reference fluid and the test fluid and the density of interest can be extracted. Short- and long-term drifts of the electronics and the ultrasonic transducer (implied) are eliminated by using the well-known pulse-echo technique, with additional frontwave detection. The method presented here is a first step in developing an ultrasonic mass flow meter.

Effect of transient ischemia on the expression of glucose transporters GLUT-1 and GLUT-4 in rat myocardium

A number of observations indicate that myocardial glucose utilization is increased late during post-ischemic reperfusion. The present study was designed to examine whether transient ischemia elicits altered expression of glucose transporters GLUT-1 and GLUT-4. In rats, the left anterior descending coronary artery was occluded for 20 min followed by reperfusion for 1, 3 or 7 days. Regional myocardial uptake and phosphorylation of glucose was determined based on myocardial accumulation of 2-deoxy-D-[2, 6-3H]glucose-6-phosphate. In hearts from fasted rats, after 3 days of reperfusion, myocardial uptake and phosphorylation of glucose was 48% higher in the reperfused region compared to a remote control region. No regional difference in myocardial glucose uptake and phosphorylation was detectable in hearts from fed rats. After 1 day of reperfusion, expression of myocardial glucose transporter GLUT-1 mRNA was increased to 195+/-24% (mean+/-SEM) of the value measured in the remote region and the expression of GLUT-4 mRNA was decreased to 58+/-7%. After 3 days of reperfusion both mRNA and protein of GLUT-1 were higher in the reperfused region, averaging 133+/-23% and 249+/-36%, respectively. The corresponding values for GLUT-4 mRNA and protein were 77+/-7% and 62+/-6%, respectively. The results indicate that a short period of ischemia alters the expression of glucose transporter isoforms GLUT-1 and GLUT-4. Observed changes may be involved in the mechanisms underlying late changes of substrate metabolism during reperfusion.

Diagnostic accuracy of Doppler-echocardiography in unselected patients with suspected pulmonary embolism

This study investigates the diagnostic value of echocardiography in patients with suspected pulmonary embolism. Doppler-echocardiography was performed in fifty consecutive patients, predominantly presenting in the emergency ward, with clinically suspected pulmonary embolism. Patients were classified as having or not pulmonary embolism by a sequential non-invasive strategy including lung scan, D-dimer measurement and lower limb venous compression ultrasonography, pulmonary angiography being performed in case of an inconclusive non-invasive work-up. The prevalence of pulmonary embolism was 36% (18 of 50 patients). Right ventricular dilatation on 2-D echocardiography associated to a tricuspid regurgitation velocity > or =2.7 m/s, corresponding to a pulmonary systolic pressure > or =39 mmHg, were present in 12 of the 18 patients (67%) with and in two of the 32 patients (6.3%) without pulmonary embolism. They were, however, absent in five of the 18 patients (28%), in whom the definite diagnosis of pulmonary embolism was made. The combination of these both echocardiographic criteria yielded a sensitivity of 67% and a specificity of 94%, positive predictive value was 86% and negative predictive value was 83%. The diagnostic performance of these two combined echocardiographic criteria, when present, permitted to reach in patients with a high clinical pre-test probability of pulmonary embolism the post-test probability values above 90%. On the other hand, the absence of these two Doppler-echocardiographic criteria did not allow to exclude pulmonary embolism, except in presence of a low pre-test probability. The findings of our study show that Doppler-echocardiography in patients with high clinical suspicion of pulmonary embolism may represent a potentially useful screening technique for the diagnosis of the disease permitting prompt initiation of treatment. However, the method does not allow to exclude pulmonary embolism in all patients with intermediate or high clinical suspicion of the disease.

Post-ischemic stimulation of 2-deoxyglucose uptake in rat myocardium: role of translocation of Glut-4

Myocardial ischemia elicits translocation of the insulin-sensitive glucose transporter GLUT-4 from intracellular membrane stores to the sarcolemma. Because glucose metabolism is of crucial importance for post-ischemic recovery of the heart, myocardial uptake of [3H]-labeled 2-deoxyglucose and subcellular localization of GLUT-4 were determined during reperfusion in isolated rat hearts perfused with medium containing 0.4 mm palmitate and 8 mm glucose. Hearts were subjected to 20 min of no-flow ischemia, followed by reperfusion for up to 60 min. Subcellular localization of GLUT-4 was determined by cell fractionation followed by immunoblotting. After 15 and 60 min of reperfusion uptake of 2-deoxyglucose was significantly higher (91+/-9 and 96+/-8 nmol/min/g wet weight, respectively) as compared to control values (65+/-1 nmol/min/g wet weight). Ischemia elicited translocation of GLUT-4 to the sarcolemma, which persisted after 15 min of reperfusion. However, after 60 min of reperfusion the subcellular distribution of GLUT-4 was similar to control hearts. In conclusion, reversal of ischemia-induced translocation of GLUT-4 to the sarcolemma is rather slow, possibly facilitating glucose uptake early during reperfusion. However, myocardial uptake and phosphorylation of 2-deoxyglucose remains enhanced late during reperfusion, when pre-ischemic distribution of GLUT-4 is almost completely restored, indicating that additional mechanisms are likely to be involved in post-ischemic stimulation of glucose uptake.

[The effect of L-carnitine on ischemic heart disease: experimental results]

L-Carnitine is a key regulatory compound of glucose and fatty acid metabolism in the myocardium. A number of experimental observations indicate that L-Carnitine may favorably influence the outcome of the myocardium after ischemic injury.

Common coronary ostium mimicking an aortic abscess in a case of bacterial endocarditis

A patient with aortic valve endocarditis presented with severe aortic regurgitation, large vegetation, and a periannular cavity at transesophageal echocardiography consistent with an abscess. At surgery a common coronary ostium was found, which was responsible for the abnormal periannular image. Such congenital abnormality, although unusual, is an echocardiographic pitfall in the case of endocarditis.

Spatial distribution of field potential profiles in the cat cerebellar cortex evoked by peripheral and central inputs

The present study was designed to characterize the spread of excitation within the frontal plane of the cat cerebellar cortex following different types of stimuli. In particular, experiments were performed to determine whether the spread of excitation evoked by mossy fibre inputs proceeds primarily along the parallel fibres ("beam-like" spread) or whether these inputs activate non-propagated foci ("patches") in the cerebellar cortex. Field potentials were recorded within a frontal plane as a medial to lateral array at different depths in parallel tracks. The recordings were made following electrical stimulation of different forelimb nerves and functionally related areas of the sensorimotor cortex as well as during passive paw movements. The resulting spatial grid of responses provides discrete spatio-temporal information reflecting the activation of specific cerebellar afferents and the neuronal interactions they evoke. The method employed demonstrates the spatial distribution of the temporal sequence of excitability changes throughout all the cerebellar cortical layers. In general, the characteristics of the responses in the intermediate cerebellar cortex depended on the source of the signals. Activity patterns evoked by peripheral nerve stimulation showed more clustered foci compared with those following electrical stimulation of functionally related areas of the sensorimotor cortex. The centrally evoked profiles were generally more homogeneous. The largest number of foci were observed following passive movements around the wrist joint. The spread of excitation in the vertical direction was evaluated by the spatial shift of the line of reversal of the N3/P2-potential (zero-isopotential line). Lines of reversal for peripherally-evoked activity patterns were approximately 90 microns closer to the molecular layer than those evoked by central stimulation in animals in which recordings have been performed in lobule Vc. The opposite was found for recordings in lobule Vb, where potential reversals following peripheral stimulation were located 40 microns deeper than those evoked following central stimulation. Cortical inputs resulted in a more proximal activation of lobule Vc Purkinje cell dendrites than in lobule Vb. This type of input processing thus seems to be lobule dependent. A beam-like spread of excitation could not be demonstrated. For both climbing fibre and mossy fibre afferent systems multiple foci were found in the frontal plane. The foci due to mossy fibre activation arose from the granular layer and expanded vertically to the molecular layer. For the climbing fibre system the foci were restricted to the molecular layer, where they merged to form a superficial band of activation. Although the data presented in this paper favour a focal distribution of activity, they do not exclude beam-like propagation along the parallel fibres, because of the difficulty of detecting this pattern in response to the stimuli. The "beam"- and "patch"-like hypotheses need not be mutually exclusive. Each could contribute to a specific stage of the temporal-spatial processing in the cerebellar cortex in a functional and task-specific manner.

Recombinant vaccinia viruses expressing the F, G or N, but not the M2, protein of bovine respiratory syncytial virus (BRSV) induce resistance to BRSV challenge in the calf and protect against the development of pneumonic lesions

The immunogenicity and protective efficacy of recombinant vaccinia viruses (rVV) encoding the F, G, N or M2 (22K) proteins of bovine respiratory syncytial virus (BRSV) were evaluated in calves, the natural host for BRSV. Calves were vaccinated either by scarification or intratracheally with rVV and challenged 6 to 7 weeks later with BRSV. Although replication of rVV expressing the F protein in the respiratory tract was limited after intratracheal vaccination, the levels of serum and pulmonary antibody were similar to those induced following scarification. The serum antibody response induced by the F protein was biased in favour of IgG1 antibody, whereas the G and the N proteins induced similar levels of IgG1:IgG2, and antibody was undetectable in calves primed with the M2 protein. The F protein induced neutralizing antibodies, but only low levels of complement-dependent neutralizing antibodies were induced by the G protein, and antibody induced by the N protein was not neutralizing. The F and N proteins primed calves for BRSV-specific lymphocyte proliferative responses, whereas proliferative responses were detected in calves primed with the G protein only after BRSV challenge. The M2 protein primed lymphocytes in only one out of five calves. Although there were differences in the immune responses induced by the rVVs, the F, G and N, but not the M2, proteins induced significant protection against BRSV infection and, in contrast with the enhanced lung pathology seen in mice vaccinated with rVV expressing individual proteins of human (H)RSV, there was a reduction in lung pathology in calves.

[Cellular recovery after ischemia: physiopathologic aspects]

Myocytes that have survived a period of transient ischemia may present prolonged alterations of cellular function, detectable during several days. The early period of postischemic reperfusion is characterized by restoration of ion homeostasis mediated by rapid resumption of function of ion pumps (Na+/K(+)-ATPase, Ca(2+)-ATPase) and transsarcolemmal ion exchange mechanisms (H+/Na+, Na+/Ca2+ exchangers). There is experimental evidence that cellular injury may be enhanced during the initial seconds or minutes of reperfusion, depending on the conditions of reperfusion. During the late phase of reperfusion mRNA expression of a number of key proteins of myocyte function is altered. The pattern of gene expression during reperfusion exhibits features of cellular adaptation and/or dedifferentiation in addition to cell repair.

[Hypertrophy due to left cardiac insufficiency: role of the neurohumoral system]

Left ventricular hypertrophy in patients with hypertensive heart disease is associated with impaired relaxation and myocardial interstitial fibrosis leading to enhanced filling pressure, referred to as left ventricular diastolic dysfunction. Impairment of systolic function, characterized by reduced ejection fraction occurs at a later stage. Activation of the renin-angiotensin-aldosterone system contributes to progression to heart failure by at least two mechanisms: (1) increased left ventricular loading conditions due to vasoconstriction and retention of sodium; (2) direct effects on the myocardium resulting in myocyte hypertrophy and interstitial fibrosis.

[Dynamic three-dimensional cardiac reconstruction by transesophageal echocardiography. A clinical experience apropos of 100 cases]

Three-Dimensional (3D) echocardiography was performed during routine transesophageal examinations in 100 patients to identify the most promising applications. The approach used was based on the integration of multiple two-dimensional images recorded with a multiplane probe to achieve 3D reconstruction. A series of 90 cardiac cycles was recorded from a fixed position during computer-controlled rotation of the transducer. The images were digitized, then reorganized according to their spatial and temporal location. The cardiac structures were then represented dynamically in three dimensions. In 100 patients referred for transesophageal echocardiography, the 3D reconstruction provided good quality images, under new angles, such as the view of the atrial aspect of the mitral valve as seen from the roof of the left atrium. This method was particularly well suited to assess mitral valve prolapse or stenosis. The spatial extent, direction and number of jets of mitral regurgitation were easily appreciated throughout systole, as were the regurgitant jets of mechanical prosthetic valves. However, the sensitivity of the 3D method was not as good as 2D echocardiography for detecting bacterial vegetations in cases of infective endocarditis. On the other hand, the determination of the precise localization of infectious, degenerative and tumoral lesions and their size were facilitated by 3D reconstruction. The authors conclude that 3D echocardiography is applicable in routine practice and the complementary information provided in certain cardiac diseases should help management of these patients.

Effect of nutritional state on substrate metabolism and contractile function in postischemic rat myocardium

The pattern of substrate utilization may influence postischemic myocardial injury. To characterize the effect of nutritional state on substrate selection and contractile function during control conditions and postischemic reperfusion, hearts from fed and fasted rats were perfused retrogradely with 0.4 mM palmitate, 8 mM glucose, and 175 mU/l insulin. Under control conditions, hearts from fasted rats exhibited lower glucose oxidation (-59%) and higher palmitate oxidation (+191%) than hearts from fed rats. During reperfusion, postischemic hearts exhibited stimulation of glucose-oxidation, with no difference between hearts from fasted and fed rats. However, oxidation of palmitate remained higher after fasting (+68%). Hearts from fasted rats exhibited lower left ventricular diastolic pressure and higher left ventricular systolic pressure development during reperfusion. The results indicate that 1) substrate selection in myocardium is influenced by the nutritional state independently of substrate availability, 2) during postischemic reperfusion, inhibition of glucose oxidation is removed in hearts from fasted rats, whereas inhibition of fatty acid oxidation in hearts from fed rats is maintained, and 3) myocardial injury is lower after fasting.

Superior mesenteric venous aneurysm

The case of a 50-year-old woman with an extremely rare venous malformation of the portal venous system is reported. The patient presented with a true aneurysm of the superior mesenteric vein, which has thus far been reported in no more than eight cases worldwide. This malformation may be congenital or acquired. Secondary aneurysms are thought to be due to liver disease, portal hypertension, trauma, or inflammation. Aneurysms of the portomesenteric venous system may be asymptomatic or give rise to severe, often dramatic conditions such as crampy abdominal pain, jaundice, and upper gastrointestinal hemorrhage secondary to portal hypertension. The diagnosis is usually made by ultrasound (B-mode or color flow Doppler), CT scan, and MRI. Invasive procedures such as venous phase mesenteric arteriography or splenoportography may be helpful in confirming it. In our opinion aneurysms of the portal venous system, even if they are congenital and (still) asymptomatic, require early surgical control because the prognosis for patients with these aneurysms is unpredictable and potential complications (e.g., portal hypertension, fistula, contained perforation, or rupture) may be fatal. In the case presented the mesenteric venous aneurysm was resected and the confluent veins were reconstructed.

Hemodynamic comparison of Medtronic intact bioprostheses and bileaflet mechanical prostheses in aortic position

Hemodynamic properties of both bioprostheses and mechanical valves have improved over the years, however, direct comparison between second-generation porcine and bileaflet valves is rare. Therefore, by the mean of Doppler echocardiography, we determined hemodynamic performances in 45 patients with Medtronic Intact bioprostheses in the aortic position and in 67 patients with bileaflet mechanical valves. Differences in pressure gradients between the two groups were essentially attributable to differences in annulus size. Indeed when the transvalvular gradient was stratified according to annulus size, mean values were no longer significantly different between Medtronic Intact porcine valves and bileaflet mechanical valves for each annulus size. In conclusion, Medtronic Intact bioprostheses in the aortic position exhibit similar hemodynamic characteristics compared to bileaflet mechanical valves.

[Asymptomatic ischemia--an important part of the spectrum of coronary disease]

Angina pectoris and asymptomatic myocardial ischemia are part of the spectrum of coronary heart disease. Not the presence or absence of angina determines the future of the patient, but repeated ischemia and the progression of the coronaropathy. This progression is neither linear with time, nor is the moment of plaque rupture foreseeable. Silent myocardial infarctions increase with age and are very frequent in diabetics. In patients without neuropathy but with asymptomatic myocardial ischemia the central pain threshold is higher than in patients with angina pectoris. The best noninvasive test for the detection, localization and estimation of extension of myocardial ischemia, be it pain-free or symptomatic, is 201-thallium scintigraphy, combined with the exercise ECG. The fight against all amendable cardiovascular risk factors and pharmacotherapy are the first steps, if asymptomatic myocardial ischemia is suspected. Augmented dyspnea on effort and rhythm disturbances are indicators of advanced multivessel heart disease. Under these circumstances coronary angiography is indicated, and further treatment should follow the generally accepted rules such as for patients with angina pectoris.

[Reconstructive surgery of the mitral valve in the acute stage of bacterial endocarditis. Apropos of 2 cases]

Two patients in our institution underwent mitral valve reconstruction during the acute phase of Staphylococcus aureus mitral valve endocarditis. In neither case was a pre-existing valve lesion found. Echocardiographic examination revealed severe mitral insufficiency and the extent of valvular lesions. In the first patient, prolapse of the posterior commissure and paracommissural areas was due to ruptured chordae tendinae. In the second patient a perforated abscess was surrounded by vegetations in the median portion of the anterior leaflet and paramedian anterior chordae tendinae were ruptured. The surgical indication was hemodynamic, combined with suspicion of repeated emboli in one case. After a 10-day course of antibiotic therapy, both patients underwent surgical repair by Carpentier's mitral valvuloplasty. During more than 6 months' follow-up no recurrence of endocarditis was observed. Both patients were in class I of the NYHA without echocardiographic evidence of residual mitral regurgitation or stenosis. Early intervention during the acute phase of endocarditis, when mitral valve destruction is not too extensive, allows mitral valvuloplasty which preserves the native valve, eradicates infected tissues and may reduce postoperative mortality and morbidity.