The benefits of incorporating the One Health concept into the organisation of Veterinary Services.

This article analyses the potential benefits of disseminating and implementing the One Health concept at the country level. It explores the need to improve administrative structures, organise inter-agency relationships, build the capacity of the veterinary profession and mainstream the issues of environment and climate change. It also stresses the importance of demographic analysis in disease control and prevention. This article contributes to the discussion by Veterinary Services on how to mainstream the One Health concept.

Pattern of hemodynamic alterations during coronary artery operations.

Twenty-four patients were studied to determine the relative importance of cardiac and peripheral factors in the hemodynamic changes associated with coronary artery operations. None had preoperative evidence of ventricular impairment. Anesthetic management was standardized for all. Sequential hemodynamic measurements revealed the following: (1) Five minutes following induction of anesthesia, all hemodynamic indices were stable except for an increase in heart rate (p less than 0.001). Sternotomy and pericardiectomy were followed by a drop in cardiac index (p less than 0.01) and systolic blood pressure (p less than 0.01). (2) Late during bypass, there was a significant, parallel reduction in both hematocrit and systemic vascular resistance (SVR) (p less than 0.001 and 0.01, respectively). (3) Five minutes after termination of bypass, cardiac output was markedly elevated (p less than 0.001) in association with a decrease in SVR (p less than 0.001), marked hemodilution (p less than 0.001), and tachycardia (p less than 0.001). (4) Following sternal closure, and despite the fact that the hematocrit was still reduced (p less than 0.001), there developed a trend of increased mean arterial pressure (MAP) and SVR with a reduction in cardiac index. These changes were further accentuated 1 hour postoperatively. The SVR was 33% higher than in the previous stage (p less than 0.01), whereas the high cardiac index recorded with initiation of bypass declined significantly to preoperative values. Throughout the studies, there was a strong correlation between alterations in hematocrit and changes in cardiac index and SVR. Blood pressure variations showed no correlation with changes in cardiac output but were significantly related to alterations of peripheral resistance. Sequential determinations of plasma renin activity and catecholamine levels showed no significant alterations in either. The alterations reported describe not only group averages but also the behavior of every patient investigated. The results suggest that in patients with normal or only mild left ventricular impairment, the major factor influencing arterial pressure variations during coronary artery operations and in the postoperative period was the change in peripheral resistance rather than alterations in cardiac output. In the treatment of hypotension under these conditions, one should take into account variations in peripheral vascular resistance and not depend solely on assumed changes in myocardial performance.

Ultrastructural myocardial preservation during coronary artery surgery: a controlled, prospective, randomized study in humans.

Potassium cardioplegia was compared with normothermic, intermittent ischemic arrest in 30 patients undergoing multiple coronary artery bypass grafts. Group 1 comprised 15 patients in whom cold potassium cardioplegia with St. Thomas' Hospital solution was used. In Group 2 were 15 patients who underwent intermittent ischemic arrest during the construction of the distal anastomoses. Two myocardial transmural left ventricular biopsies were done in each patient. There was no operative mortality. Electron microscopical examination showed normal myocardial ultrastructure in both groups. In particular, mitochondria were well preserved in all samples. The postoperative electrocardiogram demonstrated a new Q wave in 1 patient in Group 2 whose level of the myocardial isoenzyme of creatine phosphokinase (CPK-MB) was within the normal range. The peak CPK-MB release in Group 1 was 23.2 +/- 20.1 IU and in Group 2, 19.9 +/- 15.1 IU. This difference was not statistically significant. The mean period of anoxic arrest in Group 1 was 49.5 +/- 15 minutes and in Group 2, 25.5 +/- 8 minutes (p less than 0.001). Total cardiopulmonary bypass time in Group 1 was 114.5 +/- 20 minutes and in Group 2, 90.2 +/- 16 minutes (p less than 0.01). It is concluded that both techniques can preserve myocardial subcellular architecture during multiple coronary artery bypass grafting in patients with normal left ventricular function.

Failure of positive end-expiratory pressure to decrease postoperative bleeding after cardiac surgery.

To determine whether the application of positive end-expiratory pressure (PEEP) in the postoperative period after cardiac operation would reduce postoperative blood loss, the number of transfusions required, or the rate of reoperation for bleeding, we conducted a prospective study of 83 patients who underwent elective coronary revascularization. These patients were randomly assigned to receive either PEEP (10 cm H2O) or no PEEP (zero end-expiratory pressure). All other aspects of their care were identical. There was no statistically significant reduction in the amount of bleeding in patients treated with PEEP at 8 or 24 hours postoperatively. There was no significant difference in hematocrit between the groups preoperatively or postoperatively. There was no statistically significant difference in the number of reexplorations for bleeding. Finally, there was no significant difference between the groups in the amount of blood administered. On the basis of our results, we conclude that the application of PEEP in the postoperative period of cardiac operation did not reduce the amount of blood loss, the need for reexploration for bleeding, or the blood requirements in this group of patients.

Estimation of cardiac function from computer analysis of the arterial pressure waveform.

This paper presents a method for estimating parameters of a cardiovascular model, including the left-ventricular function, using the sequential quadratic programming (SQP) and the least minimum square (LMS) algorithms. In a first stage, a radial arterial-pressure waveform with corresponding cardiac output are used to automatically seek the set of parameters of the diastolic model. Computer simulation of the model using these parameters generate a pressure waveform and a cardiac output very close to those used for the estimation. In a second stage, the estimated arterial load parameters are used to select the best left-ventricular model function, from four different possibilities, and to estimate its optimum parameter values. The method has been tested numerically and applied to real cases, using data obtained from cardiovascular patients. It has also been subjected to preliminary validation using data obtained from laboratory dogs, in which cardiovascular function was artificially altered.

Disc dislodgment in Björk Shiley mitral valve prosthesis: two successfully operated cases.

Two patients with Björk Shiley mitral valve replacement had migration and embolization of the occluding disc. One patient suffered migration of the disc a few hours after surgery and the other had a strut fracture with disc translocation six years after the initial operation. Clinical signs in both cases were pulmonary edema, cardiogenic shock, and absence of prosthetic sounds. Both patients were reoperated on an emergency basis, recovering after a complicated postoperative course. They are on functional Class I, 8 and 1 years later, respectively, with their dislodged discs still in the abdominal aorta. The only hope for survival in these patients is emergency reoperation, once the prosthetic mitral valve dysfunction is confirmed.

Enhanced cardiac performance following cardiopulmonary bypass.

Changes in cardiac performance during coronary revascularization surgery were followed in 22 selected patients with normal or mildly impaired left ventricles; vasoactive or inotropic drugs were generally avoided. Arterial pressure, filling pressures, and cardiac output were measured; stroke volume and work were calculated before induction of anesthesia, following sternotomy, soon after discontinuation of extracorporeal circulation, and one hour postoperatively. Induction and sternotomy were associated with a depressant effect on cardiac performance. After extracorporeal circulation, however, cardiac performance recovered, cardiac output increased to 7 +/- 0.5 l/min from a preoperative control of 4.9 +/- 0.3 L/min (p less than 0.002) without an elevation of atrial pressures. This increase in cardiac output after bypass resulted from decreased afterload and increased preload secondary to hemodilution. Cardiac performance approached control values early in the postoperative period.

Cytochemical and electrophoretic study of the stallion epididymal glycoproteins.

It has been suggested that proteins produced in specific regions of the epididymis, mostly androgen dependent glycoproteins, are involved in the sperm maturation process. In the present work, the glycoconjugated distribution pattern and the electrophoretic characteristics of the stallion epididymal proteins were examined using lectin probes. The identification in the luminal fluid of some new proteins, probably synthesized and secreted by the epididymis, is an important initial step to investigate their interaction with the stallion sperm membrane. The binding of FITC-lectins (ConA, WGA, LPA, UEA, RCA, HPA) confirmed the presence of macromolecules containing carbohydrate residues in the epithelial cells with a distribution and relative density that was dependent on the epididymal region analyzed. The epithelium displayed affinity for more than one lectin, indicating diversity in the exposed sugar residues. The electrophoretic pattern of proteins obtained from ductus efferentes, corpus and cauda epididymis differed not only from those of the homologous blood serum, but also among the different epididymal regions. The most prominent bands correspond to 66, 55, 45 and 14 kDa proteins, present in different relative concentrations, in the three analyzed regions. A major band of 36 kDa was observed in the cauda epididymis region. The relative concentrations of protein bands of Mw 45, 36, 32, 20 and 18 kDa were significantly increased towards the distal regions of the ductus. The proteins of Mw 66, 55 and 14 kDa showed a relative higher concentration in the efferent ducts, decreasing to 25-30% in the cauda epididymal regions. The Mw 70, 66, 55, 45, 36, 32, 29, 23, 21, 18 and 14 kDa protein bands gave positive PAS reaction indicating that it corresponds to glycoproteins. Mannose residues were detected in the 70, 66, 55, 45, 36 and 32 kDa proteins. WGA-FITC binds to protein bands of Mw 70, 55, 45, 36, 32, 29, 25 and 24 kDa, suggesting the presence of N-linked glycoproteins. However, based on the resistance to the neuraminidase treatment, we suggest that the stallion epididymis contains both O- and N-glycoconjugates, probably in the N-acetyl O-diacetyl form. Although sperm maturation is an androgen-dependent process, no striking differences were detected in the SDS-PAGE obtained from animals in breeding and non-breeding seasons.

Changes in the plasma membrane proteins of stallion spermatozoa during maturation in the epididymis.

The present paper reports modifications in the electrophoretic and cytochemical characteristics of mature and immature stallion spermatozoa. Some sperm surface glycoproteins (36, 32, 29, 21, 20, 18 kDa) detected in cauda epididymidis spermatozoa, were either absent or present in a very low relative concentration in immature sperm cells. A major 14 kDa protein band, observed in sperm extracts obtained from ductus efferentes, progressively decreased along the epididymal ductus. The nature and distribution of carbohydrate residues on the sperm membrane, during epididymal maturation, was also studied by use of lectin probes. Some protein bands bound concanavalin A while others, as the 36, 32 and 20 kDa proteins, exhibited higher affinity for WGA lectin. The distribution and relative density of mannose-, galactose-, N-acetylglucosamine-, N-acetylgalactosamine-, fucose- and sialic acid-containing macromolecules showed a characteristic pattern depending on the sperm membrane domain and on its origin. Some sperm surface domains displayed affinity for more than one lectin, indicating a diversity in their exposed carbohydrate residues, whereas others bound only one or no lectin. The passage of spermatozoa through the epididymidis was accompanied by changes in the accessibility or abundance of lectin ligands. Some lectins (UEA, WGA, LPA) gave stronger reaction in mature spermatozoa, while others (RCA, WFH, PNA) stained better immature spermatozoa. This remodeling of sperm surface molecules is probably a consequence of interactions between spermatozoa and the epididymal secretions, and may reflect addition or adsorption of new molecules, space configurations changes or biochemical modifications of pre-existing compounds. Our results suggest that the distribution and density of terminal oligosaccharidic residues on the sperm plasma membrane have species-specific characteristics. These post testicular developmental changes may be of significance in the overall understanding of the stallion fertility.

Degradation of conazole fungicides in water by electrochemical oxidation.

The electrochemical oxidation (EO) treatment in water of three conazole fungicides, myclobutanil, triadimefon and propiconazole, has been carried out at constant current using a BDD/SS system. First, solutions of each fungicide were electrolyzed to assess the effect of the experimental parameters such as current, pH and fungicide concentration on the decay of each compound and total organic carbon abatement. Then a careful analysis of the degradation by-products was made by high performance liquid chromatography, ion chromatography and gas chromatography coupled with mass spectrometry in order to provide a detailed discussion on the original reaction pathways. Thus, during the degradation of conazole fungicides by the electrochemical oxidation process, aromatic intermediates, aliphatic carboxylic acids and Cl(-) were detected prior to their complete mineralization to CO2 while NO3(-) anions remained in the treated solution. This is an essential preliminary step towards the applicability of the EO processes for the treatment of wastewater containing conazole fungicides.

Physiology of the artificial heart.

Numerous deviations from normal physiology formerly ascribed to artificial heart pumping actually resulted from experimental artifacts. Recent results indicate that infection, thromboembolism, pulmonary pathology, and renal deterioration could be considered mostly nonspecific artifacts of mechanical heart implantation. Nonetheless, damage to the blood constituents and hepatic congestion seemed to be specific effects of artificial heart pumping. Hemolysis correlated to pumping sac collapse, low cardiac output, and hematocrit value (r = .912, p is less than .001). Hepatic congestion, caused by pulsatile venous hypertension and hypervolemia, was postulated to result from functional atrial volume restriction (small atrium syndrome).

[Mechanism of action of general anesthetics. Effect on ion channel proteins or on membrane phospholipids?]. / Mecanismo de acción de los anestésicos generales. Efecto sobre proteínas de canales iónicos o sobre fosfolípidos de membrana?

General anesthesia is defined by reversible unconsciousness, lack of response to noxious stimuli, and amnesia, induced by chemical agents. Mechanisms underlying the anesthetic effect are not known. The most prevalent belief was that anesthetic drugs acted on the lipid cell membranes, based on the correlation between oil solubility and anesthetic potency. Later, it has been proposed that anesthetic agents act on specific proteins of the cellular membrane of neurons. Voltage-gated ionic channels are inhibited by anesthetic agents, being some subtypes more sensitive. Clinical concentration of anesthetic agents inhibit or stimulate excitatory or inhibitory neurotransmitter receptors, respectively. Specific receptor agonists and antagonists modify this effect. Intercellular channels (gap junctions) are also affected by anesthetic agents through direct interaction with some of their protein subunits. Thus, anesthesia would result from combined effects on specific proteins acting on neural cell excitability as well as transmission and propagation of nerve impulses.

[Opioids and the immune system]. / Opioides y sistema inmune.

The immune response is partly regulated by the nervous system, that involves endogenous opioids, stimulating or depressing immune responses. Opioids modulate immune response by indirect and direct mechanisms. Indirect modulation occurs when the activation of opioid receptors within the nervous system modifies the activity of neuroendocrine axes or neurotransmission pathways. Direct modulation results from the effects of opioids on immune system cells. This requires the expression of membrane opioid receptors in these cells. Immunomodulating effects of morphine would be a result of the integration of indirect and direct effects. In animal models, morphine transiently depresses cellular and humoral immunity. In humans, morphine has similar effects; however, the real impact of morphine administration on the immune response in clinical situations in not yet known.