Oesophageal aortic echo-Doppler and TEE.
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Aorta↗
Biomedical subjects
J Lavoie
Publications and source records attributed to J Lavoie.
Two-dimensional gel electrophoresis analysis of endovacuolar organelles.
Cells perform their multiple functions with the aid of a series of distinct membrane organelles. In the last years, many of these compartments have been isolated, purified, and extensively studied. The major roles of each organelle in the cell are well understood. However, most of the molecular basis by which they perform their functions is poorly known. The recent identification and study of a handful of proteins associated with endovacuolar compartments has had a major impact on the understanding of the molecular details of organelle functions even though two-dimensional (2-D) gel analysis indicates that hundreds of proteins are typically associated with a complex organelle. This shows that many details and surprises are still to come for cell biologists. In the present study, we have analyzed and compared different organelles of the endocytic and phagocytic apparatus using 2-D gel electrophoresis.
Animals↗
Alterations of thiamine phosphorylation and of thiamine-dependent enzymes in Alzheimer's disease.
There is a growing body of evidence to suggest that thiamine neurochemistry is disrupted in Alzheimer's Disease (AD). Studies in autopsied brain tissue from neuropathologically proven AD patients reveal significantly reduced activities of the thiamine phosphate dephosphorylating enzymes thiamine diphosphatase (TDPase) and thiamine monophosphatase (TMPase) as well as the thiamine diphosphate-dependent enzymes, pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase (alpha KGDH) and transketolase. Reductions in enzyme activities are present both in affected areas of AD brain as well as in relatively well conserved tissue. Decreased TDP concentrations and concomitantly increased TMP in autopsied brain tissue from AD patients and in CSF from patients with Dementia of the Alzheimer Type suggests that CNS thiamine phosphorylation-dephosphorylation mechanisms are disrupted in AD. alpha KGDH is a rate-limiting enzyme for cerebral glucose utilization and decreases in its activity are associated with lactic acidosis, cerebral energy failure and neuronal cell loss. Deficiencies of TDP-related metabolic processes could therefore participate in neuronal cell death mechanisms in AD.
Alzheimer Disease↗
Video-assisted thoracoscopic surgery for the treatment of congenital cardiac defects in the pediatric population.
Recent technologic advances have contributed to a renewed interest in thoracoscopic surgery. In our institution, thoracoscopy through video-assisted technology has been successfully applied to congenital heart surgery. We reviewed the charts of 45 consecutive patients (ASA physical status 11-IV) who underwent video-assisted thoracoscopic surgery (VATS) for various congenital heart defects. The mean age of the patients was 2.65 yr and the mean weight was 11.78 kg. The surgical procedures included patent ductus arteriosus interruption (n = 28) and vascular ring division (n = 8), and 9 patients had miscellaneous procedures. The most commonly used anesthetic regimen consisted of isoflurane, pancuronium, fentanyl, air, and oxygen. Seven patients were managed with one-lung ventilation, the remainder by two-lung ventilation with surgical lung retraction. Intraoperative desaturation occurred in 12 patients (26.7%) but resolved quickly with brief reexpansion of the lungs. Postoperative complications included: pleural effusions (n = 3), chylothorax (n = 2), right upper lobe atelectasis (n = 1), small pneumothorax (n = 1), and vocal cord paralysis (n = 1). Seven patients (15.5%) required conversion to a thoracotomy for insufficient exposure (n = 4) or due to concern over bleeding (n = 3). This experience with VATS in pediatric patients with congenital heart disease may provide a database for comparison with others who work with the VATS technique.
Adolescent↗
Loss of [3H]kainate and of NMDA-displaceable [3H]glutamate binding sites in brain in thiamine deficiency: results of a quantitative autoradiographic study.
Previous studies suggest that alterations of brain glutamate synthesis and release occur in experimental thiamine deficiency. In order to assess the integrity of post-synaptic glutamatergic receptors in thiamine deficiency, binding sites for [3H]glutamate (displaced by NMDA), [3H]-kainate, and [3H]quisqualate (AMPA sites) were evaluated using Quantitative Receptor Autoradiography in rat brain following 14 days of treatment with the central thiamine antagonist pyrithiamine. Compared to pair-fed controls, brains of symptomatic thiamine-deficient animals contained significantly fewer NMDA-displaceable binding sites in cerebral cortex, medial septum and hippocampus. It has been suggested that NMDA-receptor mediated glutamate excitotoxicity plays a role in the pathogenesis of neuronal loss in thiamine deficiency. If such is the case, the selective loss of NMDA binding sites in cerebral cortex and hippocampus offers a possible explanation for the relative nonvulnerability of these brain regions to pyrithiamine-induced thiamine deficiency. [3H]quisqualate (AMPA) binding sites were unchanged in all brain regions of pyrithiamine-treated rats whereas [3H]kainate sites were significantly reduced in density in medial and lateral thalamus. The decline in these binding sites may be due to neuronal loss in pyrithiamine-induced thiamine deficiency. Alterations of glutamatergic synaptic function involving both NMDA and kainate receptor subclasses could contribute to the pathogenesis of neurological dysfunction in Wernicke's Encephalopathy in humans.
Animals↗
Paediatric cardiac catheterization: innovations.
In recent years interventional procedures have been introduced to the field of paediatric cardiac catheterization. These procedures continue to develop in complexity and increasingly are being applied to patients with reduced cardiovascular reserve, as an alternative to cardiac surgery or when cardiac surgery with cardiopulmonary bypass is contraindicated. More frequently anaesthetists are being called upon to provide support in sedating, anaesthetizing or/and resuscitating these patients. The purpose of this review is to give a comprehensive update of the interventional procedures and to review the anaesthetic management techniques as they apply to the catheterization laboratory. We will discuss possible complications and management strategies from our own experience and the experience of others. We have observed that as more complicated procedures are performed the anaesthetist plays a pivotal role in the management of the patient from arrival to departure from the cardiac catheterization laboratory, and in preventing mortality and major morbidity. Although the economic consequences of interventional cardiological techniques remain unclear, the field continues to expand and more complex procedures are continually being introduced.
Anesthesia, General↗
Epidural blood patch in a seven-year-old child.
We present an unusual case of postoperative headache in a child after an epidural block. A seven-year-old girl (ASA 1) was scheduled to undergo a urological procedure under general anaesthesia combined with an epidural technique for intra- and postoperative analgesia. Although there was no evidence of dural puncture when the block was performed, the patient developed a headache postoperatively. The headache, which was accompanied by neck pain, appeared in the sitting or standing position and was relieved by decubitus. According to the mother, her child had never complained of those symptoms in the past. After independent evaluation by an anaesthetist and a neurologist, a postdural puncture headache (PDPH) was considered the most likely diagnosis. As oral analgesics failed to provide relief, and epidural blood patch (EBP) using 10 ml autologous blood was performed under light sedation. This was followed by resolution of the symptoms. Epidural injections of opioids and local anaesthetics are becoming increasingly popular for pain management in children. This implies that there may be an increasing number of unintentional dural punctures that may result in more PDPHs in children. Epidural blood patches are effective in treating PDPHs in adults but their use has been reported very rarely in children. Resolution of the patient's symptoms following EBP supported the diagnosis while illustrating that EBP can be useful in the treatment of PDPH in children.
Anesthesia, Epidural↗
Intraoperative migration of a clamshell device.
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Adult↗
Detection of residual flow by transesophageal echocardiography during video-assisted thoracoscopic patent ductus arteriosus interruption.
The purpose of this study is to examine prospectively the efficacy of intraoperative transesophageal echocardiography (TEE) monitoring in reducing the incidence of residual ductal flow during video-assisted thoracoscopic (VATS) patent ductus arteriosus (PDA) interruption. Thirty consecutive patients undergoing PDA interruption via the VATS procedure were monitored with an appropriately sized Hewlett-Packard color-Doppler TEE probe. All examinations were performed by the same individual and interpreted with a cardiologist. Real time TEE monitoring was used, but the results were not disclosed to the surgeon until he was prepared to close the wound. The mean age was 2.4 yr and the average weight 11.2 kg. Two patients had residual flow after placement of the vascular clip. One patient had residual flow detected intraoperatively after placement of the vascular clip and residual flow was quickly abolished by the placement of a second clip, thus avoiding a reintervention. A follow-up transthoracic echocardiography was performed on 18 patients 1 mo postoperatively. Three patients presented residual ductal flow. This study using a novel application of TEE, demonstrates that TEE monitoring during PDA interruption may improve the surgical result, thus avoiding reintervention and the complications associated with residual ductal flow. However, late recurrence due to recanalization may occur and may not be detected by intraoperative TEE monitoring.
Adolescent↗
Effects of propofol or isoflurane anesthesia on cardiac conduction in children undergoing radiofrequency catheter ablation for tachydysrhythmias.
BACKGROUND: To determine suitability for ablation procedures in children, two commonly used anesthetic agents were studied: propofol and isoflurane. METHODS: Twenty patients presenting for a radiofrequency catheter ablation procedure were included and randomly assigned to two groups. A baseline electrophysiology study was performed during anesthesia with thiopental, alfentanil, nitrous oxide, and pancuronium in all patients. At the completion of the baseline electrophysiology study (EPS), 0.8-1.2% isoflurane was administered to patients in group 1 and 2 mg/kg propofol bolus plus an infusion of 150 micrograms.kg-1.min-1 was administered to patients in group 2. Nitrous oxide and pancuronium were used throughout the procedure. After 30 min of equilibration, both groups underwent a repeat EPS. The following parameters were measured during the EPS: cycle length, atrial-His interval, His-ventricle interval, corrected sinus node recovery time, AV node effective refractory period, and atrial effective refractory period. Using paired t tests, the electrophysiologic parameters described above measured during propofol or isoflurane anesthesia were compared to those measured during baseline anesthesia. Statistical significance was accepted as P < 0.05. RESULTS: There was no statistically significant difference in the results obtained during baseline anesthesia when compared with those measured during propofol or isoflurane anesthesia. CONCLUSIONS: Neither propofol nor isoflurane anesthesia alter sinoatrial or atrioventricular node function in pediatric patients undergoing radiofrequency catheter ablation, compared to values obtained during baseline anesthesia with alfentanil and midazolam.
Adolescent↗
Anaesthetic management of a 2.900 kg neonate with a C3-C4 dislocation.
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Anesthesia↗
Reduced activities of thiamine-dependent enzymes in brains of alcoholics in the absence of Wernicke's encephalopathy.
The relative roles of alcohol per se, thiamine deficiency, and liver disease in the pathogenesis of alcohol-related brain damage have not been fully elucidated. In particular, the extent to which alterations of brain thiamine metabolism contribute to cognitive dysfunction in alcoholism in the absence of Wernicke's encephalopathy has not been established. In the present study, thiamine diphosphate-dependent enzymes were measured using standard spectrophotometric techniques in homogenates of brain tissue obtained at autopsy from eight alcoholic patients, all of whom died in hepatic coma without clinical or neuropathological evidence of Wernicke's encephalopathy and six nonalcoholic, age-matched controls, matched for autopsy delay time and free, at the time of death, from gross malnutrition or other neurological or psychiatric disorders. Transketolase activities were reduced in cerebellum (by 35%, p < 0.01), thalamus (by 35%, p < 0.01), frontal cortex (by 22%, p < 0.01), temporal cortex (by 20%, p < 0.01), and prefrontal cortex (by 19%, p < 0.01). Activities of the pyruvate dehydrogenase complex were selectively reduced in prefrontal cortex by 25% (p < 0.01). Activities of alpha-ketoglutarate dehydrogenase were within normal limits in all brain regions of alcoholic patients. The generalized reductions of transketolase activity undoubtedly result from thiamine deficiency. Previous studies suggest that the presence of liver disease may exacerbate thiamine deficiency in alcoholics. A sustained loss of transketolase activity in brain could result in disruption of pentose shunt activity and concomitant reductions in reducing equivalents and lipid metabolism within the cell. The selective loss of pyruvate dehydrogenase activity in prefrontal cortex of alcoholic cirrhotics could relate to the phenomenon of hepatic coma.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Transoesophageal echocardiography detects residual ductal flow during video-assisted thoracoscopic patent ductus arteriosus interruption.
This report describes transoesophageal echocardiographic (TEE) monitoring in a one-year-old boy undergoing patent ductus arteriosus (PDA) interruption. After application of a first vascular clip, echocardiographic monitoring detected incomplete interruption of ductal flow, prompting the surgeon to add a second clip to the ductus. The procedure was performed via a new surgical technique: video-assisted thoracoscopic surgery (VATS). This innovative approach offers many advantages to patient care including reduced postoperative pain and better preservation of pulmonary function. We conclude that the use of TEE monitoring during PDA interruption via the VATS procedure may improve the surgical result, and eliminate reintervention and the complications associated with residual ductal flow.
Ductus Arteriosus, Patent↗
Flumazenil in cirrhotic patients in hepatic coma: a randomized double-blind placebo-controlled crossover trial.
Previous reports have suggested that "endogenous" benzodiazepines could contribute to neural inhibition in hepatic encephalopathy. RO 15-1788 (flumazenil), a specific antagonist of brain benzodiazepine receptors, could thus reverse the neurological symptoms of hepatic encephalopathy. To test this possibility, we conducted a double-blind, placebo-controlled crossover trial of the efficacy of flumazenil in cirrhotic patients in hepatic coma. Seventy-seven cirrhotic patients in hepatic coma were evaluated. Fifty-six were excluded from the trial because of multiorgan failure or because coma was precipitated by prior use of benzodiazepines, and 21 patients were randomly assigned to the flumazenil group (11 patients) or the placebo group (10 patients). Treatment was administered intravenously as a 20-ml solution (placebo or 2 mg flumazenil); seven patients were crossed over. Clinical status was assessed blindly by two observers, using a modified Glasgow scale, every 15 min for 6 hr. Electroencephalogram tracings obtained before and after drug administration were evaluated blindly by two independent observers. Serum concentrations of benzodiazepines before treatment were measured by means of a fluorescence polarization immunoassay. Improvement in neurological symptoms was observed in six patients treated with flumazenil, whereas none in the placebo group showed improvement (p < 0.05; Fisher's exact test). Improvements in electroencephalogram tracings were demonstrated in four patients treated with flumazenil, compared with two patients in the placebo group (p = NS). Benzodiazepines were found in the serum of four patients treated with flumazenil (two responders and two nonresponders); all of these patients had received pharmaceutical benzodiazepines 4 to 6 days before the trial.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
"Peripheral-type" (mitochondrial) benzodiazepine receptors in hepatic encephalopathy.
Alcoholic cirrhosis is frequently associated with episodes of portal-systemic encephalopathy (PSE). There is a growing body of evidence to suggest that the so called "peripheral-type" (non GABA-related) benzodiazepine receptors are modified in PSE. Peripheral-type benzodiazepine receptors are localized on the outer mitochondrial membrane in many tissues including brain where they are highly concentrated in astrocytes. PSE is characterized neuropathologically by astrocytic rather than neuronal changes. Densities of peripheral-type benzodiazepine receptors are significantly increased in autopsied brain tissue from alcoholic cirrhotic patients who died in hepatic coma and in the brains of rats following portacaval anastomosis. Endogenous peptide ligands for these receptors are increased in the CNS in clinical and experimental PSE.
Animals↗
Axillary plexus block using a peripheral nerve stimulator: single or multiple injections.
This prospective, randomized, double-blind study was undertaken to evaluate the success rates of axillary brachial plexus block performed with the help of a peripheral nerve stimulator when either one, two or four of the major nerves of the brachial plexus were located. Seventy-five patients undergoing upper limb surgery were randomly allocated to one of the following five groups according to the nerve and number of nerves to be located; G-1: musculo-cutaneous, radial, median and ulnar nerves; G-2: musculo-cutaneous plus one of the other three nerves; G-3: radial nerve; G-4: median nerve; G-5: ulnar nerve. The sensory block was evaluated before surgery and cutaneous anaesthesia was considered to be present when the needles of a Wartenberg Pinwheel were no longer felt in all the dermatomes of the nerves implicated in the surgical site. Otherwise, the block was considered to need completion before surgery. Only one out of the 15 patients in G-1 and G-2 needed completion of their block before surgery whereas seven out of 15 for G-3 and eight out of 15 for G-4 and G-5 needed completion of their block (P less than 0.01). We conclude that when performing an axillary block with the help of a peripheral nerve stimulator, stimulation of the musculo-cutaneous nerve and one other nerve or stimulation of all four major nerves of the brachial plexus gives a higher success rate than stimulation of only one nerve, whether the stimulated nerve is the median, radial or ulnar.
Adult↗
Effect of portacaval anastomosis on electrically stimulated release of glutamate from rat hippocampal slices.
To evaluate the effects of chronic liver failure on release of the excitatory transmitter glutamate, electrically stimulated Ca2(+)-dependent and Ca2(+)-independent release of glutamate in the absence or presence of NH4+ was studied in superfused slices of hippocampus from portacaval-shunted or sham-operated rats 4 weeks after surgery. Spontaneous and stimulation-evoked release of glutamate was higher in shunted rats in the presence of normal or low Ca2+ concentrations, and this release was depressed by 5 mM ammonium chloride. These findings suggest that portacaval shunting results in increased levels of extracellular glutamate in brain, probably due to a decreased reuptake of glutamate into perineuronal astrocytes, shown in previous studies to undergo neuropathological changes following portacaval shunting. Changes in the inactivation of transmitter glutamate could be responsible, at least in part, for the neurological dysfunction resulting from sustained hyperammonemia and portal-systemic shunting resulting from chronic liver failure.
Ammonium Chloride↗
Sequence of the Chinese hamster small heat shock protein HSP27.
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Amino Acid Sequence↗