摘要:

14C-Morphine was injected iv in control awake rats or in rats subjected to metabolic alkalosis or acidosis. Ten minutes later, radioactivity was determined within each of seven brain regions, after correction was made for intravascular tracer. In each region, parenchymal radioactivity was correlated positively and significantly (P< 0.05) with arterial bloodpH. Brain radioactivity was twofold to threefold greater in alkalotic rats (meanpH = 7.62) than in acidotic rats (meanpH = 7.16). The results are consistent with thepH-partition hypothesis for drug entry into the brain and indicate that morphine uptake can be increased by elevating the fraction of lipid-soluble uncharged morphine base in blood, by means of alkalosis. The observations may account for an exaggerated morphine-induced analgesia in alkalotic patients.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Since endotoxin, lipopolysaccharides (LPS), have been implicated as a causative factor in the development of hepatic necrosis in rats exposed to hepatotoxic levels of several chemical agents, the role of LPS in the halothane–hypoxia (HH) model of hepatic damage in male Sprague–Dawley rats was investigated. When injected intravenously immediately after halothane anesthesia, a subnecrotic dose of LPS (0.5 mg/kg;Escherichia coli026:B6) was found to markedly potentiate HH-induced hepatic necrosis. Pretreatment of the animals with the antiendotoxin agent, lactulose, prior to exposure to halothane reduced the hepatic damage normally seen from HH. A possible mechanism of LPS-induced potentiation was indicated by changes in hepatic calcium levels at 24 h after treatment. Endogenous LPS may play a role in HH-induced hepatic necrosis, and the mechanism of LPS-induced potentiation may be due to an LPS-related membrane dysfunction.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The authors conducted a double-blind crossover study to determine the effects of physostigmine salicylate on hyperoxic ventilatory response to carbon dioxide (VERCO2) and on awareness in healthy subjects previously sedated with diazepam. Diazepam 0.4 mg/kg iv decreased the slope of VERCO2from 2.41 ± 0.19 to 1.30 ± 0.15 l · min-1± mmHg-1(x ± SEM,P< 0.001). Subsequent injection of physostigmine 2.0 mg iv was associated with a 0.20 ± 0.28 l · min-1· mmHg-1decrease in slope; this was significantly different from the 0.56 ± 0.22 l · min-1· mmHg-1increase in slope associated with saline placebo (P< 0.05). Level of consciousness, on the other hand, increased more after physostigmine than after saline (P< 0.01). The authors conclude that despite an apparent increase in awareness resulting from physostigmine administration, the accompanying decrease in ventilatory drive may contraindicate its use in patients who previously have received diazepam.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The diffusion of lidocaine to myelinated and unmyelinated axons was compared on individual afferent fibers of rabbit vagus nerve. The criterion consisted of the time required for more than 95% completion of the asymptotic increase in impulse conduction time produced by a weak, nonblocking concentration of lidocaine. Measurements on sheathed and desheathed nerves for both myelinated and unmyelinated axons detected an apparent but statistically not significant diffusional lag at the perineurial sheath, averaging four minutes in this model; there was no significant difference in the mean time for attainment of criterion in myelinated and unmyelinated axons, which averaged an additional 13 min in both types of fiber. From these observations the authors conclude that lidocaine diffused as readily through the nodal gap to the excitable membrane of the myelinated fiber as through the Schwann cell mesaxon to the unmyelinated fiber. Thus differential diffusion within a nerve seems unlikely to be a contributing factor to clinical differential block.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The effect of morphine, diazepam, N2O/O2anesthesia on baroreflex control of heart rate in humans was investigated in this study. Group 1 subjects (n = 11) received morphine 0.5 mg/kg, diazepam 0.25 mg/kg, and 70% N2O with O2. Group 2 subjects (n = 10) received morphine 0.75 mg/kg, diazepam 0.25 mg/kg, and 70% N2O with O2. Phenylephrine (the pressor test), sodium nitroprusside (the depressor test), and graded neck suction were employed to alter the stimulation of baroreceptor sites. The pressor, the depressor, and neck suction baroreflex slopes declined significantly in both groups from awake to anesthetized. There was no significant difference in the degree of depression between the two groups for all three tests. Neck suction derived slopes compared favorably to the pressor test slopes (r = 0.70,P< 0.01). This study indicates that the depression of arterial baroreflex–heart rate responses under morphine, diazepam, N2O/O2anesthesia is similar to that seen with potent inhalational anesthetics such as isoflurane. Furthermore, there was no difference between the two morphine doses that were studied.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Sufentanil, a narcotic five to ten times more potent than fentanyl, reduces cortical cerebral blood flow and oxygen consumption in rats, with seizure activity occurring in some animals. However, the effects of sufentanil on blood flow and metabolism in subcortical structures have not been defined clearly. The present study examines the effects of intravenous sufentanil (40 or 160 μg/kg) on regional cerebral glucose utilization (r-CMRgl) in paralyzed, mechanically ventilated rats using 2-deoxy-D-[14C]glucose and autoradiography. Regional cerebral glucose utilization was decreased in all cortical areas examined in rats receiving either dose of sufentanil; the larger dose of sufentanil (160 μg/kg) decreased r-CMRgl in cortical structures 20–45% below control values. Two subcortical structures, the caudate nucleus and the ventral thalamic nucleus, manifested a 39–54% decrease in r-CMRgl at each dose of sufentanil. Limbic system structures responded differently. Sufentanil 40 μg/kg produced focal areas of markedly increased r-CMRgl in the amygdala of two of six rats; sufentanil 160 μg/kg produced marked increases in r-CMRgl in focal areas of hippocampus (four of eight rats) and amygdala (seven of eight rats). EEG activation suggestive of seizure activity was evident in the two low-dose sufentanil and six of the seven high-dose sufentanil rats that had focally increased r-CMRgl in the amygdala. Sufentanil causes a selective increase in r-CMRgl in subcortical limbic nuclei, particularly the amygdala, in the rat. EEG patterns of seizure activity may reflect subcortical, rather than cortical activation.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Thirty patients undergoing thoracotomy for lung resection were entered in a randomized, double-blind trial comparing the effects of epidural (E)versusintravenous (iv) morphine on postoperative pain and pulmonary function. Postoperatively the patients were given repeated doses of either 5.0 mg of morphine epidurally or 0.05–0.07 mg/kg morphine intravenously until there were no further spontaneous complaints of pain. Two, 8, and 24 h post-operatively, the following indices were measured: linear analogue pain score, somnolence score, vital signs, arterial PaO2, PaCO2andpH, forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), and peak expiratory flow rate (PEFR). Patients receiving epidural morphine had significantly less pain at 2 h (P< 0.01) and 8 h (P< 0.004) postoperatively. There was no difference in vital signs except for significantly slower respiratory rates at 2 h (P< 0.04), 8 h (P< 0.02) and 24 h (P< 0.01) in the epidural group. No significant differences occurred in the somnolence scores or blood–gas measurements, which were within normal limits. The epidural morphine group has significantly less decrease in both FVC at 2 h (E –1.8 ± 2 l, iv –2.5 ± 0.2 l,P< 0.03), 8 h (E –1.4 ± 0.2 l, iv –2.1 ± 0.2 l,P< 0.01), and 24 h (E –1.2 ± 0.2 l, iv –2.0 ± 0.2 l,P< 0.02), and FEV1at 2 h (E –1.3 ± 0.2 l, iv –1.9 ± 0.2 l,P< 0.04), 8 h (E –1.0 ± 0.2 l, iv –1.7 ± 0.2 l,P< 0.01), and 24 h (E –0.8 ± 0.1 l, iv –1.5 ± 0.2 l,P< 0.01). In addition, the epidural morphine group had significantly less decrease in PEFR at 24 h (E –134 ± 29 l · min ·-1, iv –238 ± 30 l · min-1,P< 0.03). The authors conclude that lumbar epidural morphine is highly effective in alleviating pain and improving respiratory function in postthoracotomy patients.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Previous publications have reported the initial wartime use of anesthesia for surgery as occurring in either the Crimean or German–Danish conflicts after 1848. The authors have determined that this first-time use took place in the spring of 1847 during the Mexican–American war and under the direction of American military surgeon Edward H. Barton. His experiences with ether, and those of fellow surgeon John B. Porter, are described.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Malignant hyperthermia (MH) is a pharmacogenetic disorder provoked by volatile anesthetics and depolarizing muscle relaxants. The preoperative diagnosis of MH is difficult because it requires a large muscle biopsy and a laboratory dedicated to such diagnostic studies. The authors performed electrophoresis of six muscles taken from MH patients or their relatives to determine whether the protein composition is different from normal muscle. MH muscle was found to contain large amounts of two low molecular weight proteins (15,000 daltons and 13,500 daltons) that are not present in normal muscle. Although it has not been determined that these differences are specific for MH, this finding eventually might be of assistance in diagnosing MH.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID