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.

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.

Aneurisma aórtico abdominal en pacientes mayores de 80 años: tratamiento quirúrgico convencional en 80 casos consecutivos / Abdominal aortic aneurysms in patients over 80 years of age: conventional surgical treatment in 80 consecutive cases

BACKGROUND: Abdominal aortic aneurysms (AAA) may be lethal unless appropriately and timely treated. Since age is a surgical risk, octogenarians are usually not considered as candidates for surgical intervention. AIM: To asses surgical complications and mortality in octogenarians treated for AAA. SUBJECTS AND METHODS: Patients aged 80 years older, treated consecutively between 1984-2001 were retrospectively analyzed. RESULTS: Sixty one patients were male, and their age ranged from 80 to 95 years. All were treated with open surgery. The operation was elective in 58 and as an emergency in 22 patients (symptomatic or ruptured AAA). Aortic diameter was 6.8 +/- 1.4 cm in asymptomatic patients and 7.7 +/- 1.8 cm in emergency cases (p = 0.024). Thirty days postoperative mortality was 5.1% in elective surgery compared to 40.6% in emergency operations (p < 0.01). Five years survival rate was 44.7% in asymptomatic patients compared to 10.4% in the emergency cases (p < 0.023). CONCLUSIONS: Elective surgery for asymptomatic AAA can be performed with low operative mortality in octogenarians. However, surgery in emergency cases has an 8 fold increase in risk. Accordingly, octogenarian patients should be considered for elective AAA repair in a selective basis.

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.

[Carotid endarterectomy under regional anesthesia: initial experience]. / Endarterectomía carotídea bajo anestesia regional: experiencia inicial.

BACKGROUND: Endarterectomy is the treatment of choice for internal carotid artery critical stenosis. Some authors have proposed that the use of regional anesthesia has advantages over general anesthesia. AIM: To report our initial experience with carotid endarterectomy under regional anesthesia. PATIENTS AND METHODS: Between 1998 and 1999, patients with critical carotid artery stenosis, asymptomatic or with transient and recovered symptoms, were selected. A C2, C3, C4 root deep cervical block and superficial block was performed, using a mixture of lidocaine and bupivacaine. A carotid endarterectomy with patch and without routine shunt insertion, with standard and neurological monitoring, was performed. RESULTS: During the study period, 94 carotid endarterectomies were done, 22 under regional anesthesia in 21 patients (12 male, age range 58-90 years old). Ninety five percent had hypertension, 52% smoked and 38% had renal dysfunction. One patient was converted to general anesthesia. Seventeen patients were discharged within 48 hours of the procedure and the rest, within 72 hours. There was no mortality or complications. CONCLUSIONS: Endarterectomy under regional anesthesia is less invasive, has excellent results and is well accepted by patients.

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.

[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.

A model of internal control may improve the response time of an automatic arterial pressure controller.

A simplified model for the arterial pressure control system was implemented on a personal computer using Matlab Simulink. Model responses to variations of systemic vascular resistance were comparable to those predicted by physiology. Computer simulation suggested that including this model of the internal pressure control system within the design of an external controller would achieve better arterial pressure control and faster response than previous systems.

Cardiopulmonary bypass: new strategies for weaning from cardiopulmonary bypass.

This review focuses on weaning from cardiopulmonary bypass, a very critical time for patients and anaesthetists and frequently requiring major therapeutic effort. Few novel strategies for weaning have been described recently. Most drugs or approaches described during the review period are already well established. Emphasis is placed on the importance of non-cardiac factors, and on the importance of diastolic ventricular function as opposed to systolic function.

Hemodilution does not alter the aortic-to-femoral arterial pressure difference in dogs.

INTRODUCTION: Distal arterial pressure normally differs from aortic pressure. This difference is modified by changes of vascular resistance. Hemodilution, due to decreased viscosity, decreases vascular resistance. Therefore, the difference between aortic and distal arterial pressures could be altered as well. We investigated whether acute hemodilution affected this difference in dogs. METHODS: Eleven mongrel dogs weighing 16.6 +/- 4.4 kg were anesthetized with pentobarbital and sufentanyl and mechanically ventilated. Arterial presssure was recorded using Millar catheter-tipped pressure transducers in the proximal aorta and in the distal femoral artery. An electromagnetic flowmeter probe was placed around the aorta. Effective downstream pressure was estimated by extrapolation of exponential arterial pressure decay during 3-second occlusion of the proximal aorta. Hemodilution was effected by removal of 30 ml/kg of blood and replacement with 60 ml/kg of warmed saline. In addition, the effects of 1 microg/kg phenylephrine and 4 microg/kg of sodium nitroprusside were measured before and after hemodilution. RESULTS: Hemodilution decreased hematocrit from 39 +/- 11.2% to 25.6 +/- 4.95%. Systolic and mean pressures were unchanged but aortic diastolic pressure decreased significantly, from 86 +/- 17 to 79 +/- 15 mmHg (p < 0.005). Peak systolic pressure was 13.5 +/- 7.2 mmHg higher in the femoral artery than in the aorta before, and 16 +/- 8.7 mmHg after, hemodilution (p > 0.05). Nitroprusside decreased the femoral to aortic peak systolic pressure difference from 14.3 +/- 6.3 to 7.7 +/- 15.3 mmHg, p = 0.05 before hemodilution and from 14.3 +/- 8.8 to 2.5 +/- 11 mmHg, p < 0.005 afterwards. Hemodilution significantly decreased the effective downstream pressure, from 44 +/- 9 to 36 +/- 6.8 mmHg in the aorta (p < 0.05), and from 51 +/- 2 to 37 +/- 3.1 mmHg in the distal femoral artery (p < 0.05). CONCLUSION: Acute hemodilution did not alter the aortic-to-distal arterial pressure difference in dogs.

An expert system for monitor alarm integration.

OBJECTIVE: Intensive care and operating room monitors generate data that are not fully utilized. False alarms are so frequent that attending personnel tends to disconnect them. We developed an expert system that could select and validate alarms by integration of seven vital signs monitored on-line from cardiac surgical patients. METHODS: The system uses fuzzy logic and is able to work under incomplete or noisy information conditions. Patient status is inferred every 2 seconds from the analysis and integration of the variables and a unified alarm message is displayed on the screen. The proposed structure was implemented on a personal computer for simultaneous automatic surveillance of up to 9 patients. The system was compared with standard monitors (SpaceLabs PC2), using their default alarm settings. Twenty patients undergoing cardiac surgery were studied, while we ran our system and the standard monitor simultaneously. The number of alarms triggered by each system and their accuracy and relevance were compared. Two expert observers (one physician, one engineer) ascertained each alarm reported by each system as true or false. RESULTS: Seventy-five percent of the alarms reported by the standard monitors were false, while less than 1% of those reported by the expert system were false. Sensitivity of the standard monitors was 79% and sensitivity of the expert system was 92%. Positive predictive value was 31% for the standard monitors and 97% for the expert system. CONCLUSIONS: Integration of information from several sources improved the reliability of alarms and markedly decreased the frequency of false alarms. Fuzzy logic may become a powerful tool for integration of physiological data.

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.

[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.

Estimation of ventricular volume and elastance from the arterial pressure waveform.

We propose that it is possible to estimate cardiovascular parameters from the arterial pressure waveform, including ventricular maximal elastance and end-diastolic volume, if cardiac output is also known. We tested this hypothesis by means of a parameter estimation algorithm applied to simulated arterial pressure signals. The program first estimated three coefficients representing products of passive parameters from the diastolic part of the simulated arterial pressure waveform. Second, it estimated three parameter products pertaining to the ventricular function from the systolic part of the waveform. Third, mean blood flow was entered, enabling the program to compute individual parameters. This program was tested on 200 computer-generated arterial pressure signals, obtained by simulating the model with random but bounded parameters. Correlation between estimated parameters with those actually used in the simulations was excellent. Even though the value of this computer simulation is limited to the simplified model used and requires experimental validation, it demonstrates that the technique is theoretically feasible.

[Coronary surgery. 20 years of follow-up]. / Cirugía coronaria. Veinte años de seguimiento.

BACKGROUND: Since the first surgical coronary revascularization done in Chile in 1971, 5000 such procedures have been performed. AIM: To assess the long term results of coronary revascularization surgery in our institution and to identify prognostic factors. PATIENTS AND METHODS: Five groups of 100 patients each, composed by the first consecutive patients subjected exclusively to coronary bypass surgery in the years 1975, 1980, 1985, 1990 and 1995 were retrospectively studied. RESULTS: Mean age of patients increased from a median of 52 years old in 1975 to 62 years old in 1995. No changes in the frequency of diabetes, hypertension, high serum cholesterol or previous myocardial infarction were observed. There was an increase in the proportion of patients with a recent (< 30 days) infarction that were operated along time. Seventy percent of patients had triple vessel disease or LMT and this proportion did not change. The number of grafts per patients increased form 1.9 to 3.4 and the use of arterial conduits from 0.18 to 0.81. Perioperative mortality remained constant and was 1.6%. Follow up information was obtained for 93% of 492 survivors. Actuarial survival at 5, 10, 15 and 20 years was 93 +/- 1, 82 +/- 2, 62 +/- 3 and 41 +/- 4% respectively. Ninety eight +/- 0.7, 89 +/- 2, 73 +/- 4 and 65 +/- 5% of patients remained free of a new myocardial infarction in the same lapses, respectively. Ninety seven +/- 1, 94 +/- 2, 76 +/- 4 and 47 +/- 7% of patients remained free of a new operation. Stepwise logistical regression analysis identified as bad prognostic factors, in decreasing order: cardiac failure, diabetes, smoking, hypercholesterolemia and age at the moment of operation. CONCLUSIONS: Coronary artery bypass surgery provides good and long lasting clinical improvement. The prognosis of patients is influenced by the presence of cardiac failure, some well known coronary risk factors and age at the moment of operation.

Renal protection in patients undergoing cardiopulmonary bypass with preoperative abnormal renal function.

UNLABELLED: We prospectively studied the effects of renal protection intervention in 17 patients with preoperative abnormal renal function (plasma creatinine > 1.5 mg/dL) scheduled for elective coronary surgery. Patients were randomized to either dopamine 2.0 micrograms.kg-1.min-1 (Group 1, n = 10) or perfusion pressure > 70 mm Hg during cardiopulmonary bypass (CPB) (Group 2, n = 7). Glomerular filtration rate and effective renal plasma flow were measured with inulin and 125I-hippuran clearances before the induction of anesthesia, after sternotomy and before CPB, during hypo- and normothermic CPB, after sternal closure, and 1 h postoperatively. Plasma and urine electrolytes were measured, and free water, osmolar, and creatinine clearances, as well as fractional excretion of sodium and potassium, were calculated before and after surgery. Significant differences between groups were found before CPB for glomerular filtration rate (higher in Group 1), urine output (2.0 vs 0.29 mL/min in Group 1 versus Group 2), urinary creatinine (66 vs 175 mg/dL), urinary osmolarity (370 vs 627 mOsm/L), osmolar clearance (2.1 vs 0.7 mL/min), and urinary potassium (33 vs 71 mEq/L). There were no differences between groups during hypo- and normothermic CPB. After CPB, the only difference was a slightly higher urinary creatinine in Group 2. Renal plasma flow was lower than normal in all patients before the induction of anesthesia. A nonsignificant trend toward increased flow was seen during hypothermic CPB. Filtration fraction was high before CPB, which suggests efferent arteriolar vasoconstriction, descending toward normal during and after CPB. The same pattern of changes was present in both groups. In conclusion, there were no clinically relevant differences between the two treatment modalities during and after CPB. However, significant differences were observed before CPB, when dopamine seemed to partially revert renal vasoconstriction. IMPLICATIONS: Two protective interventions were compared in patients undergoing heart surgery to prevent deterioration of renal function; these were dopamine infusion throughout the operation and phenylephrine infusion during cardiopulmonary bypass. We found clinically relevant differences only during surgery before cardiopulmonary bypass.

Renal preservation in cardiac surgery.

There is no conclusive evidence that any pharmacological intervention is able to offer effective protection for the kidneys during cardiac surgery. More research is needed into the underlying mechanisms of postoperative renal failure, specifically with regard to the possible role played by endothelial factors and inflammatory response.