Lumbar Epidural Anesthesia in the Treatment of Discal Lombosciatalgia: A Comparative Clinical Study between Methylprednisolone and Methylprednisolone with Levobupivacaine

Sousa FAEF, Colhado OCG - Lumbar Epidural Anesthesia in the Treatment of Discal Lombosciatalgia: A Comparative Clinical Study between Methylprednisolone and Methylprednisolone with Levobupivacaine. Background and objectives: Lumbar epidural technique has been used in the treatment of lombosciatalgia since 1953. In most cases, methylprednisolone is used along with a local anesthetic, and it is not known whether the isolated use of methylprednisolone is equally effective in relieving symptoms. The objective of this study was to compare the efficacy of two different solutions - methylprednisolone with saline and methylprednisolone with levobupivacaine injected in the epidural space to heal lombosciatalgia secondary to lumbar herniated disk. Methods: Sixty individuals ASA I and II, of both genders, ages 18 to 65 years participated in this randomized, double-blind study over a period of one year. They underwent interlaminar lumbar epidural analgesia without radioscopic control to heal a lombosciatalgia and they were divided into two groups: G-M (methylprednisolone + saline) and G-M + L (methylprednisolone + levobupivacaine + saline) both at a volume of 10 mL. Diagnosis was based on history, physical exam, and imaging exam (MRI). The Visual Analogue Scale (VAS) was applied in a total of two blockades, 15 days apart. Results: A reduction in pain severity was observed in the methylprednisolone-levobupivacaine group, but without statistical significance. Conclusions: The analgesic efficacy of the G-M + L solution was superior to that of the G-M solution in the treatment of discal lombosciatalgia regarding the shorter time to onset of analgesia, but this was not significant at the time of discharge, and both solutions were effective in the treatment of discal lombosciatalgia.

Role of brain nitric oxide in the thermoregulation of broiler chicks

Nitric oxide (NO) plays a key role in body temperature (Tb) regulation of mammals, acting on the brain to stimulate heat loss. Regarding birds, the putative participation of NO in the maintenance of Tb in thermoneutrality or during heat stress and the site of its action (periphery or brain) is unknown. Thus, we tested if NO participates in the maintenance of chicks` Tb in those conditions. We investigated the effect of intramuscular (im; 25, 50, 100 mg/kg) or intracerebroventricular (icv; 22.5, 45, 90, 180 mu g/animal) injections of the non selective NO synthase inhibitor L-NAME on Tb of 5-day-old chicks at thermoneutral zone (TNZ; 31-32 degrees C) and under heat stress (37 degrees C for 5-6 h). We also verified plasma and diencephalic nitrite/nitrate levels in non-injected chicks under both conditions. At TNZ, 100 mg/kg (im) or 45,90,180 mu g (icv) of L-NAME decreased Tb. A significant correlation between Tb and diencephalic, but not plasma, nitrite/nitrate levels was observed. Heat stress-induced hyperthermia was inhibited by all tested doses of L-NAME (im and icv). Tb was correlated neither with plasma nor with diencephalic nitrite/nitrate levels during heat stress. These results indicate the involvement of brain NO in the maintenance of Tb of chicks, an opposite action of that observed in mammals, and may modulate hyperthermia. (C) 2009 Elsevier Inc. All rights reserved.

On the use of Gram matrix in observability analysis

This letter presents some notes on the use of the Gram matrix in observability analysis. This matrix is constructed considering the rows of the measurement Jacobian matrix as vectors, and it can be employed in observability analysis and restoration methods. The determination of nonredundant pseudo-measurements (normally injections pseudo-measurements) for merging observable islands into an observable (single) system is carried out analyzing the pivots of the Gram matrix. The Gram matrix can also be used to verify local redundancy, which is important in measurement system planning. Some numerical examples` are used to illustrate these features. Others features of the Gram matrix are under study.

Justified Fault-Ride-Through Requirements for Wind Turbines in Power Systems

In this paper, a novel adaptive strategy to obtain technically justified fault-ride-through requirements for wind turbines (WTs) is proposed. The main objective is to promote an effective integration of wind turbines into power systems with still low penetration levels of wind power based on technical and economical considerations. The level of requirement imposed by the strategy is increased stepwise over time, depending on system characteristics and on wind power penetration level. The idea behind is to introduce stringent requirements only when they are technically needed for a reliable and secure power system operation. Voltage stability support and fault-ride-through requirements are considered in the strategy. Simulations are based on the Chilean transmission network, a midsize isolated power system with still low penetration levels of wind power. Simulations include fixed speed induction generators and doubly fed induction generators. The effects on power system stability of the wind power injections, integrated into the network by adopting the adaptive strategy, are compared with the effects that have the same installed capacity of wind power but only considering WTs able to fulfill stringent requirements (fault-ride-through capability and support voltage stability). Based on simulations and international experience, technically justified requirements for the Chilean case are proposed.

Gas flow analysis in a Kraft recovery boiler

Demands for optimal boiler performance and increased concerns in lowering emission have always been the driving force in the reevaluation and evolution of the Kraft boiler: specifically the air distribution strategies that are directly related to achieving increased residence time of flue gas combustion inside the furnace which in turn lowers atmosphere emission levels and enhances boiler operation. This paper presents the results of a study that analyzes the interaction of the different multilevel air injections have on flue gas flow patterns including various quaternary air supply arrangements. Additionally, this study assesses the performance of the CFD (Computational Fluid Dynamics) model against data available in literature. Simulations were performed considering isothermal and incompressible flows, and did not take into account thermal phenomena or chemical reactions. The numerical solutions generated proved to be coherently related to the data available in literature, and provided proof of the efficiency of tertiary level air injection, as well as revealed that quaternary air injection ports arranged in a symmetrical configuration is most suitable for optimal equipment operation. (C) 2010 Elsevier B.V. All rights reserved.

Cardiovascular Simulator Improvement: Pressure Versus Volume Loop Assessment

This article presents improvement on a physical cardiovascular simulator (PCS) system. Intraventricular pressure versus intraventricular volume (PxV) loop was obtained to evaluate performance of a pulsatile chamber mimicking the human left ventricle. PxV loop shows heart contractility and is normally used to evaluate heart performance. In many heart diseases, the stroke volume decreases because of low heart contractility. This pathological situation must be simulated by the PCS in order to evaluate the assistance provided by a ventricular assist device (VAD). The PCS system is automatically controlled by a computer and is an auxiliary tool for VAD control strategies development. This PCS system is according to a Windkessel model where lumped parameters are used for cardiovascular system analysis. Peripheral resistance, arteries compliance, and fluid inertance are simulated. The simulator has an actuator with a roller screw and brushless direct current motor, and the stroke volume is regulated by the actuator displacement. Internal pressure and volume measurements are monitored to obtain the PxV loop. Left chamber internal pressure is directly obtained by pressure transducer; however, internal volume has been obtained indirectly by using a linear variable differential transformer, which senses the diaphragm displacement. Correlations between the internal volume and diaphragm position are made. LabVIEW integrates these signals and shows the pressure versus internal volume loop. The results that have been obtained from the PCS system show PxV loops at different ventricle elastances, making possible the simulation of pathological situations. A preliminary test with a pulsatile VAD attached to PCS system was made.

Variability on red blood cell transfusion practices among Brazilian neonatal intensive care units

BACKGROUND: Guidelines for red blood cell (RBC) transfusions exist; however, transfusion practices vary among centers. This study aimed to analyze transfusion practices and the impact of patients and institutional characteristics on the indications of RBC transfusions in preterm infants. STUDY DESIGN AND METHODS: RBC transfusion practices were investigated in a multicenter prospective cohort of preterm infants with a birth weight of less than 1500 g born at eight public university neonatal intensive care units of the Brazilian Network on Neonatal Research. Variables associated with any RBC transfusions were analyzed by logistic regression analysis. RESULTS: Of 952 very-low-birth-weight infants, 532 (55.9%) received at least one RBC transfusion. The percentages of transfused neonates were 48.9, 54.5, 56.0, 61.2, 56.3, 47.8, 75.4, and 44.7%, respectively, for Centers 1 through 8. The number of transfusions during the first 28 days of life was higher in Center 4 and 7 than in other centers. After 28 days, the number of transfusions decreased, except for Center 7. Multivariate logistic regression analysis showed higher likelihood of transfusion in infants with late onset sepsis (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.8-4.4), intraventricular hemorrhage (OR, 9.4; 95% CI, 3.3-26.8), intubation at birth (OR, 1.7; 95% CI, 1.0-2.8), need for umbilical catheter (OR, 2.4; 95% CI, 1.3-4.4), days on mechanical ventilation (OR, 1.1; 95% CI, 1.0-1.2), oxygen therapy (OR, 1.1; 95% CI, 1.0-1.1), parenteral nutrition (OR, 1.1; 95% CI, 1.0-1.1), and birth center (p < 0.001). CONCLUSIONS: The need of RBC transfusions in very-low-birth-weight preterm infants was associated with clinical conditions and birth center. The distribution of the number of transfusions during hospital stay may be used as a measure of neonatal care quality.

Paclitaxel associated with cholesterol-rich nanoemulsions promotes atherosclerosis regression in the rabbit

A cholesterol-rich nanoemulsion (LDE) that resembles LDL binds to the LDL receptors and after injection into the blood stream may concentrate in cells with LDL receptor overexpression, as occurs in neoplasias and other proliferative processes. Thus, LDE can be used as vehicle to target drugs against those cells. The current study was designed to verify in rabbits whether LDE concentrates in the lesioned rabbit artery and whether a paclitaxel derivative, paclitaxel oleate, associated to LDE could reduce the atherosclerotic lesions. Sixteen male New Zealand rabbits were fed a 1% cholesterol diet for 60 days. Starting from day 30 under cholesterol feeding, eight animals were treated with four weekly intravenous injections of LDE-paclitaxel (4 mg/kg) and eight with four weekly intravenous saline solution injections for additional 30 days. On day 60, the animals were sacrificed for analysis. The uptake of LDE labeled with [C-14]-cholesteryl oleate by the aortic arch of cholesterol-fed rabbits was twice as much that observed in animals fed only regular chow. LDE-paclitaxel reduced the lesion areas of cholesterol-fed animals by 60% and intima-media ratio fourfold and inhibited the macrophage migration and the smooth muscle cell proliferation and invasion of the intima. LDE-paclitaxel treatment had no toxicity. In conclusion, LDE-paclitaxel produced pronounced atherosclerosis regression without toxicity and has shown remarkable potential in cardiovascular therapeutics. (c) 2008 Published by Elsevier Ireland Ltd.

Anti-snake venom properties of Schizolobium parahyba (Caesalpinoideae) aqueous leaves extract

Many medicinal plants have been recommended for the treatment of snakebites. The aqueous extracts prepared from the leaves of Schizolobium parahyba (a plant found in Mata Atlantica in Southeastern Brazil) were assayed for their ability to inhibit some enzymatic and biological activities induced by Bothropspauloensis and Crotalus durissus terrificus venoms as well as by their isolated toxins neuwiedase (metalloproteinase), BnSP-7 (basic Lys49 PLA(2)) and CB (PLA(2) from crotoxin complex). Phospholipase A(2), coagulant, fibrinogenolytic, hemorrhagic and myotoxic activities induced by R pauloensis and C. d. terrificus venoms, as well as by their isolated toxins were significantly inhibited when different amounts of S. parahyba were incubated previously with these venoms and toxins before assays. However, when S. parahyba was administered at the same route as the venoms or toxins injections, the tissue local damage, such as hemorrhage and myotoxicity was only partially inhibited. The study also evaluated the inhibitory effect of S. parahyba upon the spreading of venom proteins from the injected area into the systemic circulation. The neutralization of systemic alterations induced by i.m. injection of R pauloensis venom was evaluated by measuring platelet and plasma fibrinogen levels which were significantly maintained when S. parahyba extract inoculation occurred at the same route after R pauloensis venom injection. In conclusion, the observations confirmed that the aqueous extract of S. parahyba possesses potent snake venom neutralizing properties. It may be used as an alternative treatment to serum therapy and as a rich source of potential inhibitors of toxins involved in several physiopathological human and animal diseases. Copyright (c) 2008 John Wiley & Sons, Ltd.

Effect of a Pool of Peptides Isolated from Crotalus durissus terrificus (South American Rattlesnake) Venom on Glucose Levels of Mice Fed on a High-Fat Diet

This study investigated the effect of a pool of peptides, isolated from venom of Crotalus durissus terrificus (South American rattlesnake) on glucose concentration in C57BL/6 mice fed on a high-fat diet for 6 weeks. The pool of peptides (molecular mass around of 10 kDa) was obtained using a MidJet apparatus with a cartridge of 10 KDa. The peptide pool was injected intraperitoneally in mice in a single dose (0.5 mg/animal) or multiple doses (0.2 mg/dose). After predetermined times (30, 60, 90 and 120 min) post injections, venous blood samples were collected for enzymatic measurement of serum glucose using a commercial glucose kit (glucose oxidase method). High-fat fed mice showed an increase in blood glucose concentration, in comparison with mice fed on the chow diet. Thirty minutes after a single dose of the peptide pool, high-fat fed animals showed a significant decrease (similar to 47%) in glycemia. However, the glucose level increased again at 60 and 120 min. Conversely, after multiple injections of the pool of peptides administered every 30 min, the blood glucose concentration in the high-fat mice was significantly decreased (similar to 37%) and remained at low levels until 120 min. These results suggest that the tested pool of peptides from Crotalus durissus terrificus contained a peptide (or peptides) with a beneficial role on glucose-lowering action of high-fat fed mice.

The Protective Role of Lychnophora ericoides Mart. (Brazilian Arnica) in 1,2-Dimethylhydrazine-Induced Experimental Colon Carcinogenesis

Aberrant crypt foci (ACF) and colon rectal mucosal epithelial cell proliferation have been shown to be increased in patients with colon cancer and have been largely used for early detection of factors that influence colorectal carcinogenesis in rats. Fifty male Wistar rats were randomly divided into 5 groups. The groups G1 to G4 were given 4 injections of the carcinogen 1,2-dimethylhydrazine (DMH). The G2 group received Lychnophora ericoides (LE) extracts for 6 wk. The groups G3 and G4 received LE for 4 wk and 2 wk, respectively, at the postinitiation and initiation phases of colonic carcinogenesis. The group G5 was the control. Forty-two days after the first injections of DMH for the neoplasic induction, we observed a statistically significant decrease in the number of aberrant crypt foci (ACF) and an attenuation of the increase in cell proliferation induced by DMH in all the LE-treated groups. Thus, we concluded that Lychnophora ericoides extracts were effective against the development of cancer. These data suggest that LE has a protective influence on the process of colon carcinogenesis, suppressing both the initiation and the promotion of colonic carcinogenesis.

Glutamatergic neurotransmission mediated by NMDA receptors in the inferior colliculus can modulate haloperidol-induced catalepsy

The inferior colliculus (IC) is primarily involved in the processing of auditory information, but it is distinguished from other auditory nuclei in the brainstem by its connections with structures of the motor system. Functional evidence relating the IC to motor behavior derives from experiments showing that activation of the IC by electrical stimulation or excitatory amino acid microinjection causes freezing, escape-like behavior, and immobility. However, the nature of this immobility is still unclear. The present study examined the influence of excitatory amino acid-mediated mechanisms in the IC on the catalepsy induced by the dopamine receptor blocker haloperidol administered systemically (1 or 0.5 mg/kg) in rats. Haloperidol-induced catalepsy was challenged with prior intracollicular microinjections of glutamate NMDA receptor antagonists, MK-801 (15 or 30 mmol/0.5 mu l) and AP7 (10 or 20 nmol/0.5 mu l), or of the NMDA receptor agonist N-methyl-D-aspartate (NMDA, 20 or 30 nmol/0.5 mu l). The results showed that intracollicular microinjection of MK-801 and AP7 previous to systemic injections of haloperidol significantly attenuated the catalepsy, as indicated by a reduced latency to step down from a horizontal bar. Accordingly, intracollicular microinjection of NMDA increased the latency to step down the bar. These findings suggest that glutamate-mediated mechanisms in the neural circuits at the IC level influence haloperidol-induced catalepsy and participate in the regulation of motor activity. (C) 2010 Published by Elsevier B.V.

Effects of reversible inactivation of the medial septum on rat exploratory behavior in the elevated plus-maze using a test-retest paradigm

The effect of intraseptal injections of lidocaine before a first or a second session in the elevated plus-maze, in a test-retest paradigm, was investigated. In addition to gross session analyses, a minute-by-minute analysis of the sessions was used to evaluate both anxiety and memory. Lidocaine injections before the test session produced increases in the frequency of entries, time spent and distance run in the open arms without affecting activity occurring in the closed arms. During the retest session, saline- and lidocaine-treated rats exhibited increased indices of anxiety and lidocaine-treated rats exhibited decreased closed-arm entries. The minute-by-minute analysis showed a faster decrease in anxiety-related behaviors during the test session by saline- than by lidocaine-treated rats and a significant decrease in closed-arm exploration by saline-treated rats, but not by lidocaine-treated ones. Lidocaine injection before the retest session produced increases in the frequency of entries, time spent and distance run in the open arms in the second session when compared with saline-treated rats. Minute-by-minute analysis showed an increase in the time spent in the open arms by lidocaine animals at the beginning of the retest session in comparison to saline animals and a significant decrease in closed-arm exploration by both groups. These results suggest that inactivation of the medial septum by lidocaine affects the expression of unconditioned and conditioned forms of anxiety in the elevated plus-maze and, in a lesser way, the acquisition and retention of spatial information. (C) 2010 Elsevier B.V. All rights reserved.

L-Allylglycine dissociates the neural substrates of fear in the periaqueductal gray of rats

The dorsal (dPAG) and ventral (vPAG) regions of the periaqueductal gray are well known to contain the neural substrates of fear and anxiety. Chemical or electrical stimulation of the dPAG induces freezing, followed by a robust behavioral reaction that has been considered an animal model of panic attack. In contrast, the vPAG is part of a neural system, in which immobility is the usual response to its stimulation. The defense reaction induced by the stimulation of either region is accompanied by anti nociception. Although GABAergic mechanisms are known to exert tonic inhibitory control on the neural substrates of fear in the dPAG, the role of these mechanisms in the vPAG is still unclear. The present study examined defensive behaviors and antinociception induced by microinjections of an inhibitor of gamma-aminobutyric acid synthesis, L-allylglycine (L-AG; 1, 3, and 5 mu g/0.2 mu l), into either the dPAG or vPAG of rats subjected to the open field and tail-flick tests. Passive or tense immobility was the predominant behavior after L-AG (1 or 3 mu g) microinjection into the vPAG and dPAG, respectively, which was replaced with intense hyperactivity, including jumps or rearings, after injections of a higher dose (5 mu g/0.2 mu l) into the dPAG or vPAG. Moreover, whereas intra-dPAG injection of 3 mu g L-AG produced intense antinociception, only weak antinociception was induced by intra-vPAG injections of 5 mu g L-AG. These findings suggest that GABA mechanisms are involved in the mediation of antinociception and behavioral inhibition to aversive stimulation of the vPAG and exert powerful control over the neural substrates of fear in the dPAG to prevent a full-blown defense reaction possibly associated with panic disorder. (C) 2009 Elsevier Inc. All rights reserved.

Antidepressant-Like Effects of Medial Prefrontal Cortex Deep Brain Stimulation in Rats

Background: Subcallosal cingulate gyrus (SCG) deep brain stimulation (DBS) is being investigated as a treatment for major depression. We report on the effects of ventromedial prefrontal cortex (vmPFC) DBS in rats, focusing on possible mechanisms involved in an antidepressant-like response in the forced swim test (FST). Methods: The outcome of vmPFC stimulation alone or combined with different types of lesions, including serotonin (5-HT) or nore-pineprhine (NE) depletion, was characterized in the FST. We also explored the effects of DBS on novelty-suppressed feeding, learned helplessness, and sucrose consumption in animals predisposed to helplessness. Results: Stimulation at parameters approximating those used in clinical practice induced a significant antidepressant-like response in the FST. Ventromedial PFC lesions or local muscimol injections did not lead to a similar outcome. However, animals treated with vmPFC ibotenic acid lesions still responded to DBS, suggesting that the modulation of fiber near the electrodes could play a role in the antidepressant-like effects of stimulation. Also important was the integrity of the serotonergic system, as the effects of DBS in the FST were completely abolished in animals bearing 5-HT, but not NE, depleting lesions. In addition, vmPFC stimulation induced a sustained increase in hippocampal 5-HT levels. Preliminary work with other models showed that DBS was also able to influence specific aspects of depressive-like states in rodents, including anxiety and anhedonia, but not helplessness. Conclusions: Our study suggests that vmPFC DES in rats maybe useful to investigate mechanisms involved in the antidepressant effects of SCG DBS.