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Distinguishing rat brainstem reticulospinal nuclei by their neuronal morphology. II. Pontine and mesencephalic nuclei.

The purpose of this study was to determine whether pontine and mesencephalic reticulospinal nuclei like those of the medulla, can be differentiated on the basis of neuronal morphology. Accordingly, neurons of the various pontine and mesencephalic brainstem reticulospinal nuclei (BRN) of adult albino or hooded rats were either backfilled with horseradish peroxidase (HRP) from spinal injections, stained with a Nissl method or impregnated with a Golgi-Kopsch variant. The results suggest that at least 13 BRN can be distinguished in the pons and mesencephalon of the rat on the basis of neuronal morphology. The dendritic arborizations (DA) of neurons in nucleus reticularis (NR) pedunculopontinus pars compacta (RPpc), NR pedunculopontinus pars dissipatus (RPpd), NR cuneiformis (RCf) and NR subcuneiformis (RScf) are radially symmetrical. The DA of neurons in NR pontis caudalis pars beta (RPoCb) and alpha (RPoCa), as well as those of NR subcoeruleus (RSc) and the A5 cell group, exhibit a pronounced dorsomedial to ventrolateral slant. The dendrites of locus coeruleus (LC) neurons slant from dorsolateral to ventromedial. The DA of NR pontis oralis pars medialis (RPoOm) neurons course medially, while those of NR pontis oralis pars lateralis (RPoOl) course laterally. The DA of Kolliker-Fuse neurons (KF) course horizontally. Finally, the DA of the nucleus raphe dorsalis (RaD) are either symmetrically multipolar or fusiform. The neurons of RPoCb, RPpc, KF and RCf project to the spinal cord with a strong ipsilateral predominance, while those of LC, RSc, RPoOm and RPpd project to the spinal cord with a weak ipsilateral predominance. The axons of A5, RPoOl and RaD neurons exhibit no lateral predominance in their spinal projections. Finally, RPoCa neurons, as well as neurons in RScf, project to the spinal cord with a strong contralateral predominance. The neurons of RPoCb, RPoCa, RPoOl, RPpd and RScf project to the spinal cord via the mlf and sulcomarginal fasciculus. The neurons of RSc, KF, RPoOm, RPpc and RCf project to the spinal cord via the lateral funiculus.

Animals↗

Distinguishing rat brainstem reticulospinal nuclei by their neuronal morphology. I. Medullary nuclei.

While cytoarchitectonic and hodological investigations suggest that the brainstem reticulospinal nuclei (BRN) are complexly organized, previous Golgi studies claimed that BRN comprise a homogeneous population with respect to neuronal morphology. To determine whether this is indeed the case, neurons of the various BRN of adult albino or hooded rats were either backfilled with horseradish peroxidase (HRP) from spinal injections, stained with a Nissl method or impregnated with a Golgi-Kopsch variant. The results suggest that at least thirteen BRN can be distinguished in the medulla. Some medullary BRN contain neurons whose dendritic arborizations (DA) are radially symmetric (e.g., nucleus reticularis (NR) ventralis pars beta (RVb), NR gigantocellularis (RGc) and nucleus raphe magnus (RaM]. Some BRN contain neurons whose DA exhibit a pronounced dorsomedial to ventrolateral slant (e.g., NR dorsalis (RD) and NR parvocellularis (RPc). The DA of NR paragigantocellularis dorsalis (RPgcd) neurons tend to course dorsally. The DA of nucleus raphe obscurus (RaO) neurons course vertically, while those of NR magnocellularis pars alpha (RMca) and NR magnocellularis pars beta (RMcb) course horizontally. The DA of NR ventralis pars alpha (RVa) may be oriented horizontally also, but sometimes slant from dorsolateral to ventromedial. The DA of NR paramedianus neurons (RPm) are cruciform. The neurons of NR paragigantocellularis lateralis (RPgcl) and of the nucleus raphe pallidus (RaP) exhibit a variety of DA patterns. The neurons of RD, RVa, RMcb and RMca project to the spinal cord with a strong ipsilateral predominance, while those of RVb, RPgcl and RGc project to the spinal cord with a weak ipsilateral predominance. The axons of RPc, RaO, RaP, and RaM neurons exhibit no lateral predominance. RPm neurons project to the cord with a weak contralateral predominance, and RPgcd neurons project to the cord with a strong contralateral predominance. Most medullary BRN project to the spinal cord via the medial longitudinal fasciculus (mlf) and sulcomarginal fasciculus. However, RPgcl, RMca and RMcb also project to the spinal cord via the lateral funiculus. The neurons of RD, RPm and RaM project to the spinal cord exclusively via the lateral or dorsolateral funiculus. Since the various medullary BRN are distinguishable on the basis of neuronal morphology, they may play distinct roles in brainstem modulation of spinal motor, sensory or autonomic activity.

Animals↗

Prevention of hypotension during spinal anesthesia for cesarean delivery: an effective technique using combination phenylephrine infusion and crystalloid cohydration.

BACKGROUND: Many methods for preventing hypotension during spinal anesthesia for cesarean delivery have been investigated, but no single technique has proven to be effective and reliable. This randomized study studied the efficacy of combining simultaneous rapid crystalloid infusion (cohydration) with a high-dose phenylephrine infusion. METHODS: Nonlaboring patients scheduled to undergo elective cesarean delivery received an intravenous infusion of 100 mug/min phenylephrine that was started immediately after spinal injection and titrated to maintain systolic blood pressure near baseline values until uterine incision. In addition, patients received infusion of lactated Ringer's solution that was given either rapidly (group 1, n = 57) or at a minimal maintenance rate (group 0, n = 55). Maternal hemodynamic changes and neonatal condition were compared. RESULTS: Six patients were excluded from analysis. Only 1 of 53 patients (1.9% [95% confidence interval, 0.3-9.9%]) in group 1 experienced hypotension versus 15 of 53 patients (28.3% [95% confidence interval, 18.0-41.6%]) in group 0 (P = 0.0001). Compared with group 0, patients in group 1 had greater values for the following: serial measurements of systolic blood pressure (P = 0.02), minimum recorded systolic blood pressure (P = 0.0002), and minimum recorded heart rate (P = 0.013). Total phenylephrine consumption was smaller in group 1 compared with group 0 (P = 0.008). Neonatal outcome and maternal side effects were similar between groups. CONCLUSIONS: Combination of a high-dose phenylephrine infusion and rapid crystalloid cohydration is the first technique to be described that is effective for preventing hypotension during spinal anesthesia for cesarean delivery.

Adult↗

An attempt to withdraw coverage by the insurance company in the event of gross negligence. Costs totalling US $ 4.5 million.

In its judgement of 11 June 1993, the Court of Appeal of Brussels upheld the personal liability of a trainee and the in solidum liability of the hospital in a case where an erroneous spinal injection caused permanent paraplegia and incontinence. Although the attempt of withdrawal coverage by the insurance company on base of the concept of gross negligence, did not succeed in this case, it is clear that under the new insurance law of 25 June 1992, several risks will not be covered by the insurance companies in the future. The exemplary list of gross negligence cases, which may be used by the insurance companies, involves predominantly anesthesiology practice. The coverage of several insurance contracts exclude e.g., damages resulting from simultaneous anesthesia, or from the absence of an anesthesiologist during the full course of the surgery and damages resulting from anesthesia in the absence of necessary monitoring and reanimation equipment.

Anesthesia, Spinal↗

Small dose bupivacaine-fentanyl spinal analgesia combined with morphine for labor.

UNLABELLED: We investigated the duration of labor analgesia produced by a small dose of spinal bupivacaine/fentanyl alone or in combination with a small dose of morphine. Sixty parturients were enrolled in this placebo-controlled, double-blinded, randomized trial. All women received a spinal injection of 12.5 micro g of fentanyl with 2 mg of bupivacaine. The morphine group (MBF) also received 125 micro g of morphine; the placebo group (BF) received saline. Pain scores were <3 of 10 within 10 min of injection. The median duration of analgesia was similar between groups (89 min versus 84 min; P = not significant), and only 20% of the MBF group experienced prolonged analgesia. During subsequent epidural analgesia, the MBF group had a significantly lesser rate of breakthrough pain (0.15 +/- 0.14 episodes per hour versus 0.26 +/- 0.18 episodes per hour; P = 0.02). Also, during the first 24 h postpartum, the MBF group required significantly fewer medications (3.3 +/- 3.7 doses versus 4.7 +/- 3.5 doses; P = 0.04). Intrathecal injection of this small dose of bupivacaine/fentanyl produced a rapid onset of labor analgesia; the addition of a small dose of morphine did not significantly prolong analgesia, but it improved subsequent pain relief, as measured by the rate of breakthrough pain and postpartum medication requirements. This may provide a clinically useful means of improving intra- and postpartum pain relief. IMPLICATIONS: A small dose of intrathecal fentanyl 12.5 micro g and bupivacaine 2 mg produces effective labor analgesia lasting for approximately 85 min. The addition of a small 125- micro g dose of morphine improves pain control during subsequent epidural analgesia and reduces the requirements for postpartum pain medications.

Adult↗

The effect of leukaemia inhibitory factor on SOD1 G93A murine amyotrophic lateral sclerosis.

Before potential therapeutic strategies for the treatment of amyotrophic lateral sclerosis (ALS) can be advanced to human clinical trials, there is a need to assess them in an animal model that best resembles the disease process. SOD1 G93A mice have close resemblance to familial ALS (fALS) and have been used in this study to evaluate the therapeutic potential of leukaemia inhibitory factor (LIF). LIF action was investigated by assessing three delivery methods: (1) daily subcutaneous injection; (2) through LIF rods placed adjacent to hind limb skeletal muscle and (3) continuous intrathecal infusion. The effect on disease progression was assessed by semi-quantitative and quantitative functional measurements, and histologically on the survival of motor neurons and number of reactive astrocytes. The results show that LIF had no beneficial effects when administered using the three methods of drug delivery. These results suggest that further evaluation of LIF in this transgenic model is required to fully characterize its' therapeutic potential.

Amyotrophic Lateral Sclerosis↗

Glycopyrronium and hypotension following combined spinal-epidural anaesthesia for elective Caesarean section in women with relative bradycardia.

The ability of glycopyrronium to reduce the severity of hypotension following subarachnoid block in parturients with a relative bradycardia was evaluated in a double-blind randomised controlled study. Women with a resting heart rate of < or = 80 beat x min(-1) presenting for elective Caesarean section were randomly allocated to receive either glycopyrronium 2 microg x kg(-1) or normal saline intravenously once positioned for combined spinal-epidural anaesthesia. Following spinal injection of 2.6 ml hyperbaric bupivacaine 0.5% and fentanyl 15 microg, women randomly allocated to the saline group were given 6 mg ephedrine so that all parturients received some prophylaxis against hypotension other than the fluid preload. Further ephedrine and fluid boluses were administered if mean arterial pressure fell 20% or more from resting values. Using a sequential analysis technique, analysis after the first 20 subjects indicated the study should be stopped, with no difference in ephedrine requirements or hypotension between the groups. We conclude that pretreatment with glycopyrronium 2 microg x kg(-1) is no more effective than 6 mg ephedrine in preventing hypotension following subarachnoid block in parturients with relatively low resting heart rates.

Adult↗

Leg elevation and wrapping in the prevention of hypotension following spinal anaesthesia for elective caesarean section.

Ninety-seven parturients undergoing elective Caesarean section were allocated randomly to have their legs elevated to approximately 30 degrees on pillows or elevated and wrapped with elasticated Esmarch bandages or neither (controls) following spinal anaesthesia. All patients received intravenous crystalloid (20 ml.kg-1 over 20 min) prior to spinal injection and were placed in the left lateral tilt position. Significant hypotension was treated with intravenous ephedrine in 5 mg bolus doses. Leg wrapping resulted in a significant reduction in the incidence of postspinal hypotension in comparison to the control group (18% compared to 53%, p = 0.004). This represents a five-fold reduction in the likelihood of postspinal hypotension (odds ratio 5.3, 95% CI 1.7-16.3). Leg elevation alone did not significantly reduce the incidence of hypotension (39%). There was no significant difference in the time of onset of hypotension between the groups. For those patients requiring ephedrine, there was no significant difference in mean dose requirements between the groups. The use of leg compression immediately postspinal provides a simple means of reducing the accompanying hypotension and should be used more widely.

Adult↗

Oxygen transport and cardiovascular responses in skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacares) exposed to acute hypoxia.

Responses to acute hypoxia were measured in skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacares) (approximately 1-3 kg body weight). Fish were prevented from making swimming movements by a spinal injection of lidocaine and were placed in front of a seawater delivery pipe to provide ram ventilation of the gills. Fish could set their own ventilation volumes by adjusting mouth gape. Heart rate, dorsal and ventral aortic blood pressures, and cardiac output were continuously monitored during normoxia (inhalant water (PO2 greater than 150 mmHg) and three levels of hypoxia (inhalant water PO2 approximately 130, 90, and 50 mmHg). Water and blood samples were taken for oxygen measurements in fluids afferent and efferent to the gills. From these data, various measures of the effectiveness of oxygen transfer, and branchial and systemic vascular resistance were calculated. Despite high ventilation volumes (4-7 l.min-1.kg-1), tunas extract approximately 50% of the oxygen from the inhalant water, in part because high cardiac outputs (115-132 ml.min-1.kg-1) result in ventilation/perfusion conductance ratios (0.75-1.1) close to the theoretically ideal value of 1.0. Therefore, tunas have oxygen transfer factors (ml O2.min-1.mmHg-1.kg-1) that are 10-50 times greater than those of other fishes. The efficiency of oxygen transfer from water in tunas (approximately 65%) matches that measured in teleosts with ventilation volumes an order of magnitude lower. The high oxygen transfer factors of tunas are made possible, in part, by a large gill surface area; however, this appears to carry a considerable osmoregulatory cost as the metabolic rate of gills may account for up 70% of the total metabolism in spinally blocked (i.e., non-swimming) fish. During hypoxia, skipjack and yellowfin tunas show a decrease in heart rate and increase in ventilation volume, as do other teleosts. However, in tunas hypoxic bradycardia is not accompanied by equivalent increases in stroke volume, and cardiac output falls as HR decreases. In both tuna species, oxygen consumption eventually must be maintained by drawing on substantial venous oxygen reserves. This occurs at a higher inhalant water PO2 (between 130 and 90 mmHg) in skipjack tuna than in yellowfin tuna (between 90 and 50 mmHg). The need to draw on venous oxygen reserves would make it difficult to meet the oxygen demand of increasing swimming speed, which is a common response to hypoxia in both species.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Combined spinal epidural analgesia is the preferred technique for labour analgesia.

To justify its place as the preferred method of pain relief in labour, CSE must demonstrated a clear superiority over epidural analgesia. Looking at the relative efficacy of the two techniques failure rates appear to be equal. Speed of onset may be faster with an initial spinal injection although perhaps only clinically relevant in advanced labour where the quality of analgesia may sometimes be better. CSE would not seem to offer significant advantage in terms of mode of delivery or the ability to ambulate. The side effects of the technique are somewhat more concerning as CSE would appear to carry slightly greater risk than epidural analgesia, most notably in neurological sequelae and the effects of intrathecal opioids. Certainly CSE confers no benefit in terms of cost. What then is the place of CSE in labour analgesia? Its potential benefit makes it a reasonable option when there is a clear clinical advantage such as requests for analgesia in late labour or where maternal distress is extreme or where epidural analgesia has been ineffective. However even in such situations the slight increase in risk must be weighed against the possible advantage. Consequently the CSE cannot at the present time be recommended as the preferred option for labour analgesia.

Adult↗

The sitting versus right lateral position during combined spinal-epidural anesthesia for cesarean delivery: block characteristics and severity of hypotension.

In the present study we evaluated whether the sitting position during initiation of small-dose combined spinal-epidural anesthesia (CSE) would induce less hypotension as compared with the lateral position. Sixty women undergoing elective cesarean delivery were randomly assigned to receive a spinal injection consisting of 6.6 mg hyperbaric bupivacaine with sufentanil 3.3 microg in either the lateral or the sitting position. After securing the epidural catheter, patients were turned to a 15 degrees left lateral supine position. Ephedrine 5 mg IV was administered prophylactically and subsequently in case of nausea/vomiting and/or hypotension, defined as a systolic blood pressure less than 95 mm Hg or a 25% decrease from baseline values. Although the incidence of ephedrine supplementation was not different, females in the sitting group required less ephedrine (P = 0.012) and there were fewer problems with identifying the epidural space (P = 0.01). However, more patients in this group required epidural supplementation (35% versus 3%; P = 0.007). In the lateral group, blocks extended more cephalad than with the sitting position (P = 0.014). Apgar scores did not differ, but umbilical artery pH values were significantly higher in patients of the sitting group (7.31 +/- 0.04 versus 7.26 +/- 0.03; P = 0.02). We conclude that performing a CSE technique for cesarean delivery in the sitting position was technically easier and induced less severe hypotension.

Adult↗

Clinical and pharmacokinetic aspects of the combination of meperidine and prilocaine for spinal anaesthesia.

The aim of this study was to determine whether the addition of a small dose of prilocaine could augment the spinal block induced by meperidine and affect intrathecal meperidine pharmacokinetic behaviour. Spinal anaesthesia was performed in 60 men scheduled for endoscopic resection of a prostatic adenoma or bladder tumour under spinal anaesthesia. They were allocated randomly to receive either 1 mg.kg-1 meperidine (Group 1, n = 30), or 1 mg.kg-1 meperidine plus 0.5 mg.kg-1 prilocaine (Group 2, n = 30). Blood samples were collected prior to and for 24 hr after spinal injection in 24 patients (12 in each group). Plasma meperidine levels were assayed by gas chromatography. Complete motor block was achieved in all Group 2 patients, but was incomplete in seven of Group 1 (P less than 0.05). The onset of both motor and sensory blocks was shorter (P less than 0.01) in Group 2 and the duration was longer (P less than 0.05). Coadministration of prilocaine modifies meperidine pharmacokinetic behaviour. The area under curve was 48% greater (P less than 0.01) and Cmax was higher in Group 2 than in Group 1, 145.8 +/- 42.2 vs 107 +/- 20.5 ng.ml-1 (P less than 0.001). No evidence of respiratory depression was noted in any of the patients. Despite the increase in plasma meperidine concentrations, no side effects were observed. The plasma concentrations remained at one third to one sixth the levels reported to induce a respiratory depression. It is concluded that the addition of prilocaine to meperidine improves motor and sensory block during surgery and alters meperidine kinetics without producing major side effects.

Aged↗

Phenylephrine added to prophylactic ephedrine infusion during spinal anesthesia for elective cesarean section.

BACKGROUND: Because ephedrine infusion (2 mg/min) does not adequately prevent spinal hypotension during cesarean delivery, the authors investigated whether adding phenylephrine would improve its efficacy. METHODS: Thirty-nine parturients with American Society of Anesthesiologists physical status I-II who were scheduled for cesarean delivery received a crystalloid preload of 15 ml/kg. Spinal anesthesia was performed using 11 mg hyperbaric bupivacaine, 2.5 microg sufentanil, and 0.1 mg morphine. Maternal heart rate and systolic blood pressure were measured at frequent intervals. A vasopressor infusion was started immediately after spinal injection of either 2 mg/min ephedrine plus 10 microg/min phenylephrine or 2 mg/min ephedrine alone. Treatments were assigned randomly in a double-blind fashion. The infusion rate was adjusted according to systolic blood pressure using a predefined algorithm. Hypotension, defined as systolic blood pressure less than 100 mmHg and less than 80% of baseline, was treated with 6 mg ephedrine bolus doses. RESULTS: Hypotension occurred less frequently in the ephedrine-phenylephrine group than in the ephedrine-alone group: 37% versus 75% (P = 0.02). Ephedrine (36+/-16 mg, mean +/- SD) plus 178+/-81 microg phenylephrine was infused in former group, whereas 54+/-18 mg ephedrine was infused in the latter. Median supplemental ephedrine requirements and nausea scores (0-3) were less in the ephedrine-phenylephrine group (0 vs. 12 mg, P = 0.02; and 0 vs. 1.5, P = 0.01, respectively). Umbilical artery pH values were significantly higher in the ephedrine-phenylephrine group than in the group that received ephedrine alone (7.24 vs. 7.19). Apgar scores were similarly good in both groups. CONCLUSION: Phenylephrine added to an infusion of ephedrine halved the incidence of hypotension and increased umbilical cord pH.

Adult↗

Hyperbaric dye solution distribution characteristics after pencil-point needle injection in a spinal cord model.

BACKGROUND: The flow-rate limiting and directional characteristics of caudally directed microcatheters, which lead to intrathecal maldistribution of hyperbaric 5% lidocaine, are believed to have contributed to at least 11 cases of cauda equina syndrome. The authors investigated the distribution characteristics of hyperbaric dye solutions via caudally directed side port needles at various rates of injection in a spinal cord model to determine the potential for maldistribution. METHODS: Using a digital video image processing technique, we injected a hyperbaric solution of phthalocyanine blue dye through caudally directed side-port needles into a supinely oriented transparent spinal canal model filled with simulated cerebrospinal fluid. Injections via commonly used spinal needles (24-gauge and 25-gauge Sprotte, and 25-gauge and 27-gauge Whitacre) were recorded using five injection rates (2, 4, 6, 8, and 16 ml/min). RESULTS: For all needles tested, injection rate had a significant effect on the peak dye concentration (P < 0.0001). Injection rates > or = 6 ml/min (2 ml/20 s) resulted in peak dye concentrations of less than 168 mg/1 (extrapolated concentration of 1% lidocaine). Injection via the 24-gauge Sprotte needle, which has a larger orifice area and internal diameter, resulted in significantly lower peak dye concentrations than via the smaller Whitacre needles tested (P < 0.05). CONCLUSIONS: Sacral maldistribution could be minimized by using injection rates > or = 6 ml/min (2 ml/20 s), for all of the side-port spinal needles used in this model study. When very slow injection rates (2 ml/min) are used, peak dye concentrations varied inversely and significantly with needle internal diameter and orifice area.

Anesthetics, Local↗

The effects of solution concentration and epinephrine on lateral distribution of hyperbaric tetracaine spinal anesthesia.

In a search of a differential spinal block between dependent and nondependent sides, we investigated whether the use of a larger concentration of hyperbaric tetracaine (T) and/or the omission of epinephrine (E) would provide differential spread in patients left for 15 min in the lateral decubitus position. Spinal anesthesia was performed in the lateral decubitus position with the operated side dependent in 60 patients scheduled for lower limb surgery. All patients remained lateral for 15 min after spinal injection before being turned supine. They received 12 mg of T in 10% dextrose and E 0.2 mg was added when predicted duration of surgery was more than 90 min. The concentration of T to be used for each patient was randomized. This resulted in four groups of 15 patients: T 0.5% + E (control group), T 1% + E, T 0.5%, and T 1%. A unilateral anesthesia was defined as the presence of an adequate sensory (L-1 or higher) and/or motor (3 degrees) blockade on the dependent side and the absence of one or both modalities on the nondependent side, or as a duration of sensory (regression to L-2) and motor (1 degrees of recovery) blockade 20% longer on the dependent compared to the nondependent side. None of the 60 patients showed unilateral sensory block. A comparable number of patients in all groups showed unilateral motor block: four in T 0.5% + E, two in T 1% + E, four in T 0.5%, and five in T 1%. Likewise, a comparable number of patients in all groups showed a prolonged duration of sensory and motor block, respectively: six and eight in T 0.5% + E, six and nine in T 1% + E, six and eight in T 0.5%, and seven and seven in T 1%. In conclusion, although a preferential distribution of hyperbaric T toward the dependent side in patients of all four groups was noticed, the use of a larger concentration of T, omission of E, or combination of these two factors did not provide a more marked differential spread when compared to the standard solution of T 0.5% + E.

Adrenergic Agonists↗

[Application of combined epidural-spinal anesthesia in pediatric surgery and postoperative analgesia].

OBJECTIVE: To compare the anesthetic and analgesic efficacy of ropivacaine and bupivacaine and their side reactions in combined spinal-epidural anesthesia (CSEA) and postoperative analgesia in pediatric surgery. METHODS: Fifty children for lower abdominal surgery, aged 6-14 years, were randomly assigned to receive either ropivacaine (Group R, n=25) or bupivacaine (Group B, n=25) for CSEA. Spinal injection for Group R was a mixture of 1.5 ml of 10 g x L(-1) ropivacaine, 0.5 ml distilled water and 1ml of 100 g x L(-1) dextrose. The injection for Group B was the same as that for Group R except 0.5 ml of 7.5 g x L(-1) bupivacaine. The terminal concentrations of anesthetics were 5 g x L(-1) for the two groups. The injection volume was calculated as: ml=(age x 0.2 + weight x 0.5) divided by 2. When operations prolonged to 1.5 h, epidural infusion at the rate of 1 mg x (kg(-1) x h(-1)) started with 2.5 g x L(-1) ropivacaine for Group R and 2.5 g x L(-1) bupivacaine for Group B. The observed variables were the changes in blood pressure, heart rate, SpO(2), block level, visual analogue scores, and motor block. Epidural postoperative analgesia was performed for Group R with 100 ml of 0.75 g x L(-1) ropivacaine to which 100 mg tramadol and 5 mg were added, and for Group B with 100 ml of 0.75 g/L(-1) bupivacaine instead. Backgroup infusion was 3 ml x h(-1) for the children aged 6-9 years or 4 ml x h(-1) for the children aged 10-14 years, bolus was 2 ml controlled by children or their parents when necessary, and locktime was 15 min. The observed variables were the efficacy of postoperative analgesia, recession of motor block of legs, and the incidence of headache, nausea and vomiting, leg numbness, and urinary retention within 24 h after operation. RESULTS: There was no significant difference between the two groups in block level. Motor block was much milder in Group R than that in Group B during operation, and recessed faster after operation. Only one case of nausea occurred in each group, and one case of urinary retention in Group B without statistical significance. CONCLUSION: Either ropivacaine or bupivacaine can be satisfactorily used in CSEA for analgesia during and after operation. However, ropivacaine has a weaker motor block than bupivacaine, which benefits early walking after operation and recovery of bowl movement.

Adolescent↗

Coexistence of glutamate and substance P in dorsal root ganglion neurons of the rat and monkey.

Antisera to a glutamate (Glu) conjugate, to glutaminase (GLN), and to substance P (SP) have been used to investigate the issue of putative glutamergic neurons in the dorsal root ganglia (DRG) and the possible coexistence in these neurons of Glu and SP. The Glu antiserum, characterized by immunoadsorption and immunoblot tests, is highly selective for Glu out of a number of other amino acids including aspartate. Quantitative data were gathered from consecutive 4-microns-thick paraffin sections from cervical ganglia of rats with or without spinal injections of colchicine and from one monkey not treated with colchicine. Neurons containing more than one antigen could be identified on adjacent sections tested with the three different antisera. Neurons labeled by the Glu-antiserum represent 15-30% of the DRG population in untreated rats. They include most of the small neurons (with mean perikaryal area around 300-400 microns) but also larger neurons (with perikaryal area greater than 600 microns). DRG neurons labeled by either the GLN or the SP antiserum are small (mean area 335-375 microns and 356-374 microns, respectively) and account for approximately 40 and 15%, respectively, of the sampled neurons. In colchicine-treated rats the number of Glu-positive neurons increases up to about 70%. The same treatment also increases the number of SP-positive neurons but not that of GLN-positive neurons. In the monkey about half of the DRG neurons are Glu positive and, as in rats, they are mostly small. GLN-positive neurons in the same species account for about half of the DRG population and are only small. In rats, about 60-80% of Glu-positive neurons are also GLN-positive and most GLN-positive neurons are Glu positive. In colchicine-treated rats, close to 90% of SP-positive neurons are also positive for Glu and about 60% of SP-positive neurons are triple labeled. In the monkey's DRGs, whose sections were not processed for SP, most Glu- or GLN-positive neurons are also positive for the other antiserum used. Several considerations argue against the possibility that, under the present experimental conditions, the Glu antiserum is a metabolic marker. It is therefore suggested that Glu-positive neurons may use Glu as neurotransmitter. Coexistence of Glu and SP in some DRG neurons suggests that both agents may be released by terminals of primary afferents from the same DRG neuron.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Effect of morphine on growth of metastatic colon cancer in vivo.

Control of colon cancer depends, in part, on intact immune defense mechanisms. Since opiates are known to affect some components of immune function, this study was conducted to determine the effect of high-dose subcutaneous morphine sulfate and of low-dose intrathecal morphine on the postoperative growth of metastatic colon cancer. Five groups of 15 Fischer 344 rats were given intraportal injections of colon cancer cells as follows: group 1, control; group 2, daily subcutaneous injections of 20-mg/kg morphine the day before and for 2 days after colon cancer cell inoculation; group 3, daily subcutaneous injections of saline; group 4, daily intrathecal injections of 20 micrograms of morphine; and group 5, daily intrathecal injections of saline. There was a significant decrease in the hepatic tumor burden in group 2 compared with groups 1 and 3 and a significant increase in the hepatic tumor burden in groups 4 and 5 compared with group 1. This study demonstrates that intermittent injections of a narcotic may decrease the growth of tumor cells that gain access to the circulation during a surgical procedure. In addition, the results support the concept that tumor cells entering the circulation during a vulnerable period of postoperative immunosuppression are more likely to survive as metastatic tumor.

Adenocarcinoma↗