ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Recent evidence suggests that anesthetic agents may act by disordering the lipid phase of nerve cell membranes, and that increased pressure reverses the anesthetic effect by increasing order among lipid molecules. It is conceivable that high pressure may simply lower the anesthetic concentration at its presumed site of action by displacing anesthetic molecules from the membrane, or alternatively, that high pressure may directly reorder lipid membranes, the concentration of the anesthetic agent in the membrane remaining the same. The latter alternative is supported by the results of the present study, in which electron spin resonance techniques were used to demonstrate that the small spin-labeled molecule TEMPO is only partially displaced from phospholipid membranes by pressures which reverse anesthesia invivo.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

The electromyogram (EMG) and tension evoked by single and tetanic stimuli were studied during curarization in anesthetized subjects.d-Tubocurarine depressed both evoked twitch tension and EMG, but not identically. Before curarization posttetanic potentiation (PTP) was present on tension recordings but not on EMG recordings. Small amounts of tetanic fade were present on both tension and EMG recordings before curarization. On tension recordings PTP and fade increased significantly only during profound curarization, while on EMG recordings both increased at all levels of curarization. Electromyography is more sensitive than tension recordings in the investigation or monitoring of curarization.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

To investigate whether metabolites of halothane could act as haptens and thus account for part of the hepatic damage sometimes seen after repeated halothane anesthesias, known and suggested metabolites of halothane were coupled to chicken serum globulin. Rabbits were subsequently immunized with these complexes, and the production of antibodies was tested by immunodiffusion in agar gel. In all cases similar precipitin lines were formed against the complexes used for immunization in each rabbit, as well as against the trifluoro- compound coupled to the rabbits' own serum proteins, bovine serum albumin, or poly-L-lysine. This indicates that the trifluoro- compounds studied form partly identical antigenic determinants and can act as haptens.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

One hundred and five percutaneous radial-artery cunnulations were prospectively studied in 100 patients. The patients were examined daily for complications, utilizing physical examination and Doppler flow measurements. Forty of the 105 cannulations (38 per cent) resulted in radialartery thrombosis. Arterial occlusion occurred in 25 per cent of 43 vessels cannulated for less than 20 hours, in 50 per cent of 40 cannulations lasting 20 to 40 hours, and in 41 per cent of 22 cannulations lasting 40 to 144 hours. Radial arterial pulses, produced by retrograde ulnar-artery flow, were palpabledistalto 73 per cent of the radialartery thrombi, and Doppler flow signals were audible distal to 90 per cent of the thrombi.Arterial occlusion was found at the time of decannulation in only 42.5 per cent of those vessels which eventually thrombosed. An additional 30 per cent of the total number of thrombi developed within 24 hours of decannulation. However, 27.5 per cent first occurred later than one day after decannulation. All of the 20 thrombosed vessels which were followed during return visits recanalized. The longest time taken for recanalization was 75 days. No major ischemic complication was observed in any patient, despite the high incidence of temporary thrombosis. Histologic specimens from three cannulated radial arteries were obtained at subsequent postmortem examinations; photomicrographs of these specimens showed a pathologic picture consistent with the clinical impression.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Lethal and abrupt hyperthermia can be produced in rats when a sublethal dose of 2,4-dinitrophenol (10 µg/g, ip) is administered during anesthesia with 2 per cent halothane in a chamber kept at 25 C, but not at 20 C. Dinitrophenol injection, after about an hour, triples the metabolic rate, increases the rectal temperature to above 44 C, and produces skeletal muscle rigor at the time of death. Muscle mitochondria from rats treated with dinitrophenol + halothane show uncoupled oxidative phosphorylation but no acceleration of respiration. Treatment with halothane or dinitrophenol separately does not produce lethal hyperthermia or uncoupling in skeletal muscle mitochondria. Liver mitochondria from lethally hyperthermic rats show normal oxidative phosphorylation. Pretreatment with L-thyroxine does not sensitize rats to halothane, nor do peripheral anti-thyroxine agents prevent or reverse the dinitrophenol + halothane syndrome; Mg++salts do prevent the muscle rigor. Lethal fulminant hyperthermia can be produced in laboratory animals not chosen for genetic susceptibility by administering an uncoupling agent during halothane anesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

The effects of halothane on the cyclic 3',5'- adenosine monophosphate (cyclic AMP) system and on smooth muscle contractility were studiedin vitroin rat uterus. Halothane increased the activities of both adenyl cyclase and phosphodiesterase in a dose-dependent fashion. Halothane stimulated the adenyl cyclase activity to a greater extent than that of phosphodiesterase. Uterine tissue levels of endogenous cyclic AMP were also increased by halothane. Acetylcholine-induced contraction of the rat uterus was inhibited by halothane in concentrations similar to that affecting the cyclic AMP system. These results suggest that the action of halothane in relaxing the uterine muscle is related to an increased intracellular cyclic AMP owing to increased activity of adenyl cyclase. In contrast to epinephrine, these effects of halothane were not antagonized by beta-adrenergic blocking compounds, propranolol and MJ 1999, indicating that the action of halothane on uterine smooth muscle is not mediated through the beta-adrenergic receptors as previously suggested.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

A nonlinear mathematical model of anesthetic uptake and distribution has been used to account for changes in ventilation and perfusion induced by progressive increase in anesthetic depth. The results show greater differences in anesthetic uptake than have been predicted from models that have not considered the effects of anesthetics on these physiologic variables. During spontaneous ventilation with halothane or isoflurane, the higher the inspired concentration, the slower the rate of alveolar anesthetic increase. Progressively increasing ventilatory depression, and eventually apnea, limit delivery of anesthetic to the lung and prevent alveolar concentration from rising above 3 per cent, regardless of the inspired concentration. During controlled ventilation with halothane, alveolar concentration increases as cardiac output diminishes. As cardiac arrest occurs, the alveolar curves become unstable and rapidly rise to the inspired concentration. The use of such nonlinear models may allow prediction of limits to which anesthetic drugs and techniques can be used safely.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

A survey of the 621 female nurse-anesthetists in Michigan was performed to determine the incidence of malignancy in this group. Two separate mailings and telephone interviews resulted in a response rate of 84.5 per cent. A total of 33 malignancies in 31 nurse-anesthetists was reported. Several unusual types were noted. Ten malignancies, including three skin cancers, were diagnosed during 1971. Excluding skin cancers, the expected incidence adjusted for age distribution, based on statistics from the Connecticut Tumor Registry, is 402.8/100,000. The adjusted incidence in Michigan nurse-anesthetists is 1,333.3/ 100,000. This difference is significant at the 3.1 per cent level.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID