共查询到20条相似文献,搜索用时 31 毫秒
1.
SKAGGS ML 《California medicine》1949,70(2):130
Sterilizing solutions that by accident become mixed into the anesthetic agent are probably the etiological factor producing many of the neurological complications following spinal anesthesia. Use of sterilizing solutions having an intensity of color so great that even one drop in the contents of an ampule will definitely color the anesthetic agent is the criterion of safety. 相似文献
2.
Investigating the interactions between universal and culturally specific influences on color categorization across individuals and cultures has proven to be a challenge for human color categorization and naming research. The present article simulates the evolution of color lexicons to evaluate the role of two realistic constraints found in the human phenomenon: (i) heterogeneous observer populations and (ii) heterogeneous color stimuli. Such constraints, idealized and implemented as agent categorization and communication games, produce interesting and unexpected consequences for stable categorization solutions evolved and shared by agent populations. We find that the presence of a small fraction of color deficient agents in a population, or the presence of a “region of increased salience” in the color stimulus space, break rotational symmetry in population categorization solutions, and confine color category boundaries to a subset of available locations. Further, these heterogeneities, each in a different, predictable, way, might lead to a change of category number and size. In addition, the concurrent presence of both types of heterogeneity gives rise to novel constrained solutions which optimize the success rate of categorization and communication games. Implications of these agent-based results for psychological theories of color categorization and the evolution of color naming systems in human societies are discussed. 相似文献
3.
Alpha-chloralose as a canine anesthetic 总被引:4,自引:0,他引:4
4.
This review provides information to scientists performing animal surgery with recommendations for choosing an appropriate anesthetic agent. The human health risks from exposure to various anesthetic agents as well as methods to minimize exposure are discussed. In brief, methoxyflurane, used with precautions, is recommended for rodent bench-top surgery. When a precision vaporizer is available, isoflurane is usually the agent of choice. Other agents, including injectables, are considered. 相似文献
5.
The absorption spectra of visual purple solutions extracted by various means were measured with a sensitive photoelectric spectrophotometer and compared with the classical visual purple absorption spectrum. Hardening the retinas in alum before extraction yielded visual purple solutions of much higher light transmission in the blue and violet, probably because of the removal of light-dispersing substances. Re-extraction indicated that visual purple is more soluble in the extractive than are the other colored retinal components. However, the concentration of the extractive did not affect the color purity of the extraction but did influence the keeping power. This suggests a chemical combination between the extractive and visual purple. The pH of the extractive affected the color purity of the resulting solution. Over the pH range from 5.5 to 10.0, the visual purple color purity was greatest at the low pH. Temperature during extraction was also effective, the color purity being greater the higher the temperature, up to 40°C. Drying and subsequent re-dissolving of visual purple solutions extracted with digitalin freed the solution of some protein impurities and increased its keeping power. Dialysis against distilled water seemed to precipitate visual purple from solution irreversibly. None of the treatments described improved the symmetry of the unbleached visual purple absorption spectrum sufficiently for it to resemble the classical absorption spectrum. Therefore it is very likely that the classical absorption spectrum is that of the light-sensitive group only and that the absorption spectra of our purest unbleached visual purple solutions represent the molecule as a whole. 相似文献
6.
W. J. Crozier 《The Journal of general physiology》1922,4(6):723-731
The penetration of acid into mantle tissue of Chromodoris zebra is accelerated after local faradic stimulation, and is retarded by brief treatment with anesthetic solutions. The spontaneous outward diffusion of intracellular pigment is an inadequate criterion of "permeability." Outward diffusion of pigment and penetration of acid are both facilitated when the tissue is artificially put under tension. 相似文献
7.
The role of phosphotungstic acid as the main pH-controlling agent in Papanicolaou's EA stain was analyzed, including its effect on the competition between eosin Y and light green, the principal components of EA solutions, and this acid was compared with HCl as an acidifying agent. The amount of phosphotungstic acid in the solution determined the color of the cytoplasm. Our study led to a better understanding and a simplification of the staining procedure. With the acquired knowledge, the Papanicolaou counterstain can be standardized to suit the taste of the individual cytologist and can add to the predictability of the results. 相似文献
8.
Neurochemical Research - Inhaled anesthetic agents may be neurotoxic to the developing brain of a neonatal rodent. Isoflurane is a commonly used volatile anesthetic agent for maintenance of general... 相似文献
9.
Francisco Gómez Christophe Phillips Andrea Soddu Melanie Boly Pierre Boveroux Audrey Vanhaudenhuyse Marie-Aurélie Bruno Olivia Gosseries Vincent Bonhomme Steven Laureys Quentin Noirhomme 《PloS one》2013,8(8)
Mechanisms of propofol-induced loss of consciousness remain poorly understood. Recent fMRI studies have shown decreases in functional connectivity during unconsciousness induced by this anesthetic agent. Functional connectivity does not provide information of directional changes in the dynamics observed during unconsciousness. The aim of the present study was to investigate, in healthy humans during an auditory task, the changes in effective connectivity resulting from propofol induced loss of consciousness. We used Dynamic Causal Modeling for fMRI (fMRI-DCM) to assess how causal connectivity is influenced by the anesthetic agent in the auditory system. Our results suggest that the dynamic observed in the auditory system during unconsciousness induced by propofol, can result in a mixture of two effects: a local inhibitory connectivity increase and a decrease in the effective connectivity in sensory cortices. 相似文献
10.
Aurin M. Chase 《The Journal of general physiology》1936,19(4):577-599
Visual purple from winter frogs shows an intermediate yellow color during bleaching by light; summer extractions do not. This seasonal effect can be duplicated by variations in the hydrogen ion concentration and in the temperature of the solutions. Increasing the pH approximates the summer condition, while decreasing the pH approximates the winter condition. Temperature has no effect on the bleaching of alkaline solutions but greatly influences acid solutions. At low temperatures the bleaching of add solutions resembles the winter condition, while at higher temperatures it resembles the summer condition. A photic decomposition product of frog retinal extractions is an acid-base indicator: it is yellow in acid and colorless in alkaline solution. Its color is not dependent upon light. The hydrogen ion concentration of visual purple solutions does not change under illumination, nor is there a difference in the pH of summer and winter extractions. Bile salt extractions of visual purple are usually slightly acid. The conflicting results of past workers regarding the appearance of "visual yellow" may be due to seasonal variation with its differences in temperature, or to the presence of base in the extractions. It is also possible that vitamin A may be a factor in the seasonal variation. The photic decomposition of visual purple in bile salts solution, extracted from summer frogs, follows the kinetics of a first order reaction. Visual purple from winter frogs does not conform to first order kinetics. Photic decomposition of alkaline, winter visual purple extractions also follows a first order equation. Acid, winter extractions appear to conform to a second order equation, but this is probably an artefact due to interference by the intermediate yellow. 相似文献
11.
Effect of anesthetic agents on lavage fluid parameters used as indicators of pulmonary injury 总被引:3,自引:0,他引:3
The effect of the anesthetic agent used in killing animals in an in vivo pulmonary toxicity screening test was examined in Fischer-344 rats and in Syrian hamsters. Using animals killed by cervical dislocation with no anesthesia as a baseline, two types of anesthetic agents (halothane, sodium pentobarbital) and carbon dioxide were tested. Carbon dioxide caused the greatest perturbance of baseline lavage fluid and tissue parameters normally used in the screening test. Halothane anesthesia caused the least perturbance in the screening test parameters and was selected as the anesthetic of choice for use in future pulmonary toxicity tests. 相似文献
12.
The topical use of anesthetic agents involves an element of risk. Systemic toxic reactions are rare, but they do occur and may result in death. When a reaction occurs from a topical application, it usually progresses rapidly to respiratory and cardiovascular collapse, and thus therapy must be instituted with more haste to avoid deaths. Fatal systemic toxic reactions from topically administered anesthetic drugs are, in effect, usually not due to well informed use of the drug but to misuse owing to less than complete understanding of absorption.Emphasis is placed on the causes, prophylaxis and treatment of severe systemic toxic reactions which follow the topical application of local anesthetic drugs. If systemic toxic reactions resulting from a safe dose of a local anesthetic agent are correctly treated, there will usually follow an uneventful recovery rather than a catastrophe. 相似文献
13.
The diffusion of ligands and proteins was proposed to be guided by chreodes in water organized by protein-surface side chains with varying hydropathic states. These chreodes are proposed to be the target of volatile general anesthetic agents. The similarity between this effect and sleep deprivation leads to a proposal of an external agent responsible for sleep. This agent is elemental nitrogen. An extension of this effect is the concept that elemental nitrogen is a core factor in aging. 相似文献
14.
David Lindsay Downie Francisco Vicente-Agullo Antonio Campos-Caro Trevor John Bushell William Robert Lieb Nicholas Peter Franks 《The Journal of biological chemistry》2002,277(12):10367-10373
Some neurotransmitter-gated ion channels are very much more sensitive to general anesthetics than others, even when they are genetically and structurally related. The most striking example of this is the extreme sensitivity of heteromeric neuronal nicotinic acetylcholine receptors to inhalational general anesthetics compared with the marked insensitivity of the closely related homomeric neuronal nicotinic receptors. Here we investigate the role of the alpha subunit in determining the anesthetic sensitivity of these receptors by using alpha(3)/alpha(7) chimeric subunits that are able to form functional homomeric receptors. By comparing the sensitivities of a number of chimeras to the inhalational agent halothane we show that the short (13 amino acids) putative extracellular loop connecting the second and third transmembrane segments is a critical determinant of anesthetic sensitivity. In addition, using site-directed mutagenesis, we show that two particular amino acids in this loop play a dominant role. When mutations are made in this loop, there is a good correlation between increasing anesthetic sensitivity and decreasing acetylcholine sensitivity. We conclude that this extracellular loop probably does not participate directly in anesthetic binding, but rather determines receptor sensitivity indirectly by playing a critical role in transducing anesthetic binding into an effect on channel gating. 相似文献
15.
James R. Trudell 《生物化学与生物物理学报:生物膜》1977,470(3)
Seeman and coworkers (Seeman, P. (1972) Pharmacol. Rev. 24, 583–655) calculated that anesthetic agents exapnd membrane volume ten times more than the van der Waals volume of the agent alone. Their calculation was based on the assumption that the thickness of the erythrocyte membrane expands at the same rate as the surface area. However, recent data on bilayer membranes demonstrate that an expansion of membrane surface area is accompanied by a decrease in membrane thickness. A reinterpretation of their erythrocyte area expansion data using an appropriate contraction of membrane thickness suggests the volume in a membrane occupied by anesthetic molecules is approximately equal to their van der Waals volume. 相似文献
16.
Alpha-chloralose suppression of neuronal activity 总被引:4,自引:0,他引:4
Alpha-chloralose, an anesthetic agent widely used in neurophysiologic studies, caused a significant and long-lasting suppression of single neuron activity recorded from two areas of the central nervous system in decerebrate cats. A 50 mg/kg dose (an average anesthetic dose used in many neurophysiologic studies) caused suppression of spontaneous and evoked activity of neurons in the dorsal horn of the spinal cord and greater suppression of neurons in the nucleus reticularis gigantocellularis (NRGC) of the medial medullary reticular formation. Many researchers are of the opinion that alpha-chloralose causes less suppression of the central nervous system (CNS) than other commonly used anesthetic agents. The neuronal suppression recorded in this study appears similar in many ways to suppression caused by other anesthetic agents in the same two areas of the CNS. The results of the present study suggest that alpha-chloralose may be capable of producing significant suppression of neurons in the dorsal horn of the spinal cord and NRGC. Its ability to influence other areas of the CNS should not be inferred from these results, but the data do indicate the importance of evaluating the effects of anesthetics upon neurophysiologic systems under study. 相似文献
17.
Kier LB 《化学与生物多样性》2007,4(10):2473-2479
The work and inspiration of Robert Rosen is stated and expressed in personal tones. The concept of passages through water (H2O) near protein surfaces is reviewed in terms of its influence on ligand diffusion to an effector. This is offered as a target for interference by a non-specific general anesthetic agent. In view of the similarities between this anesthetic state and sleep, this mechanism is proposed to be operative for the sleep/wake states. Based on this mechanism and other factors, nitrogen (N2) is proposed as an exogenous sleep factor. 相似文献
18.
Samuel Gendel 《The Western journal of medicine》1950,72(1):37-39
Many of the observations made in the management of large bowel injuries during World War II are applicable to similar cases encountered in civilian practice.Early administration of whole blood to combat shock cannot be overemphasized.The patient should be adequately examined for associated injuries.Ether-oxygen is the anesthetic agent of choice, and a closed technique should be used.Vertical incision offers the best exposure for the operation and is most rapidly performed.The surgical principles of exteriorization and/or a proximal colostomy to completely divert the fecal stream are the important features in the technical management of the injured large bowel.A method of colostomy closure is presented. 相似文献
19.
Metoclopramide is a dopamine receptor antagonist used in animals as both an antiemetic and a gastroprokinetic agent. In chickens, the drug causes central nervous system depression. The authors examined the potential sedative and hypnotic effects of metoclopramide when administered in combination with the anesthetic agent ketamine in 1-3-week-old chicks. Concomitant administration of metoclopramide and ketamine markedly reduced the median effective doses (ED50s) of both drugs for the induction of sedation and sleep in the chicks. The results suggest potential therapeutic applications of the metoclopramide-ketamine combination as a restraining agent in avian species not intended for human consumption. 相似文献
20.
Anesthetic Gases and Water Structure : The effect of xenon on tritiated water flux across the gut
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Eugene Y. Berger F. Rene Pecikyan Grace Kanzaki 《The Journal of general physiology》1968,52(6):876-886
Pauling and Miller have independently proposed that the presence of an anesthetic gas in tissue induces a cage-like arrangement of hydrogen-bonded water molecules. The theories recognize that most gas-hydrate crystals would not form at the temperature and pressure that exist during anesthesia and propose that other components of tissue such as protein should have a stabilizing effect. Measurements of the behavior of water, rather than the anesthetic agent, would provide alternative information about the likelihood of hydrate crystal formation and this information could be such as to be applicable to body temperature and to pressures used for anesthesia. If the number of hydrogen-bonded water molecules in tissue is increased, then the movement of an average water molecule should be hindered. Movement of water through the tissue may be measured by tagging it with tritium and the anesthetic gas should then slow the movement of tritiated water through the tissue. The flux of tritiated water through rat cecum is indeed slowed when the cecum is exposed to the anesthetic gas, xenon, which can participate biochemically only by virtue of its van der Waals interaction. The decrement in water flux is in reasonable agreement with what could be expected theoretically from calculations based on the activation energy for the self-diffusion of water and the degree of hypothermia necessary to produce narcosis. 相似文献