The efficacy of dexamethasone in extending the duration of local anaesthetic block is uncertain. In a randomised controlled triple blind crossover study in volunteers, we tested the hypothesis that neither i.v. nor perineurally administered dexamethasone prolongs the sensory block achieved with ropivacaine.
Methods
Ultrasound-guided ulnar nerve blocks (ropivacaine 0.75% wt/vol, 3 ml, with saline 1 ml with or without dexamethasone 4 mg) were performed on three occasions in 24 male volunteers along with an i.v. injection of saline 1 ml with or without dexamethasone 4 mg. The combinations of saline and dexamethasone were as follows: control group, perineural and i.v. saline; perineural group, perineural dexamethasone and i.v. saline; i.v. group, perineural saline and i.v. dexamethasone. Sensory block was measured using a VAS in response to pinprick testing. The duration of sensory block was the primary outcome and time to onset of sensory block the secondary outcome.
Results
All 24 subjects completed the trial. The median [inter-quartile range (IQR)] duration of sensory block was 6.87 (5.85–7.62) h in the control group, 7.37 (5.78–7.93) h in the perineural group and 7.37 (6.10–7.97) h in the i.v. group (P=0.61). There was also no significant difference in block onset time between the three groups.
Conclusion
Dexamethasone 4 mg has no clinically relevant effect on the duration of sensory block provided by ropivacaine applied to the ulnar nerve.
Background: Drugs are routinely combined in anesthesia and pain management to obtain an enhancement of the desired effects. However, a parallel enhancement of the undesired effects might take place as well, resulting in a limited therapeutic usefulness. Therefore, when addressing the question of optimal drug combinations, side effects must be taken into account.
Methods: By extension of a previously published interaction model, the authors propose a method to study drug interactions considering also their side effects. A general outcome parameter identified as patient's well-being is defined by superposition of positive and negative effects. Well-being response surfaces are computed and analyzed for varying drugs pharmacodynamics and interaction types. In particular, the existence of multiple maxima and of optimal drug combinations is investigated for the combination of two drugs.
Results: Both drug pharmacodynamics and interaction type affect the well-being surface and the deriving optimal combinations. The effect of the interaction parameters can be explained in terms of synergy and antagonism and remains unchanged for varying pharmacodynamics. For all simulations performed for the combination of two drugs, the presence of more than one maximum was never observed. 相似文献
BACKGROUND: A low level of response to alcohol has been associated with both the genetic constitution of the regulatory region (SLC6A4) of the human serotonin (5-hydroxytryptamine, 5-HT) transporter (5-HTT) and with future alcohol intake and an increased risk for alcoholism. To date, all studies of relevant polymorphisms have been carried out in populations in the United States. METHODS: Data were extracted from a subset (n = 243) of a cohort of children who have been observed since birth through evaluation of the family history of alcoholism and psychosocial risk influences. At age 16 years, the response to alcohol was assessed with the Self-Rating of the Effects of Alcohol (SRE) questionnaire, and the average amount of alcohol intake per month was assessed during the prior 6 months. Additional variables that were measured included the 5-HTT genotype, externalizing behavior, and sociodemographic variables, such as gender and age. RESULTS: The level of response to alcohol was significantly lower among carriers of two long alleles of the 5-HTT regulatory region compared with carriers of one or two short alleles (Mann-Whitney U = 5225.0, p = .005). In a multiple regression analysis, the level of response to alcohol and externalizing behavior but not psychosocial factors significantly predicted the average amount of alcohol intake per month. CONCLUSIONS: This study demonstrates that, independent of the assessed psychosocial variables, the 5-HTT genotype correlated with the level of response to alcohol and predicted alcohol intake among 16-year-old adolescents. 相似文献
A case of an uncommon congenital primitive neuroectodermal cerebellar tumor (PNET) in a 5-month-old child is reported. After subtotal surgical resection, the residual tumor did not respond to radiation and chemotherapy. Histologically, the tumor was composed of small, round, undifferentiated cells and several other patterns like astrocytomatous, oligodendrogliomatous, and ependymomatous structures. Immunostaining was positive for most of the cells for vimentin and S 100, fewer were positive for glial fibrillary acid protein (GFAP) and neuron-specific enolase, and only a few for synaptophysin. Surprisingly, the tumor showed strong expression of several monoclonal cytokeratins (CK) with different molecular weights, together with epithelial membrane antigen. Furthermore, we found a coexpression of the tumor cells for CK and vimentin, while CK-GFAP and CK-S 100 were negative. Ultrastructurally, intracyto-plasmic intermediate filaments could be observed corresponding to immunohistochemical CK expression. The very strong CK and vimentin expression in this case was interpreted as a sign of the embryonic nature of the tumor. 相似文献
In order to clarify the reported discrepancies in S100 alpha protein and mRNA distribution in rat tissues, a rat S100 alpha cDNA has been isolated and this species homologous probe along with a rat S100 beta cDNA probe has been used to examine S100 mRNA expression in rat tissues. Although the rat S100 alpha cDNA was missing approximately 30 nucleotides of coding sequence, only 4 conservative changes in amino acid sequence were observed when the deduced amino acid sequence was compared to the bovine S100 alpha amino acid sequence. Thus, S100 alpha proteins, like S100 beta proteins, are highly conserved among species. All nineteen of the tissues examined (including cerebrum and cerebellum) contained S100 alpha mRNA. In addition, S100 beta mRNA was detected in thirteen of the nineteen tissues examined. These results are in agreement with previous protein distribution studies and further demonstrate that S100 proteins are not brain-specific and are expressed in a large number of tissues. Although S100 alpha and S100 beta mRNAs were detected in rat tissues which had previously been reported to contain S100 alpha and S100 beta protein, a direct correlation between the protein and mRNA levels were not observed, suggesting that different mechanisms regulate S100 expression in various tissues. S100 alpha exhibited a single similar size mRNA species (0.5 Kb) in all tissues examined, as did S100 beta (1.5 Kb), suggesting that the individual S100 proteins are expressed as single mRNA and protein products in rat tissues. 相似文献
1. In two rabbits subjected to prolonged injections with crystalline egg albumin the antibodies in one showed progressive changes such as noted in an earlier paper; the antibodies in the other did not. 2. The significance of this behavior in the production of sera for therapeutic use is pointed out. 3. Quantitative studies are reported on the low grade or incomplete antibody present in the early stages of immunization of a horse with egg albumin. 4. Quantitative studies on the flocculating antibody from later bleedings from the horse are given, and the dissociation of the soluble pre-zone compounds by rabbit anti-egg albumin is studied. Rough velocity estimations are reported. 5. The bearing of the findings on the mechanism of precipitin and flocculation reactions and of the Danysz effect is discussed in terms of the union of multivalent antigen with multivalent antibody. 相似文献
With 1–1.5 million cases reported every year cutaneous leishmaniasis represents an increasing health problem. The course of cutaneous leishmaniasis varies from a single self‐healing ulcer to a persistent ulcer or progressive mucosal disease with nasopharyngeal destruction. An enormous array of topical and systemic treatment modalities has been endorsed. The response to treatment depends on the species of parasite as well as the host's immunological and genetic status. Species‐specific treatment guidelines based on evidence from controlled studies are highly desirable. We present two cases of cutaneous leishmaniasis, one in a child and one during pregnancy, reviewing various diagnostic and therapeutic measures with special attention to problems in young and pregnant patients. 相似文献
Background: Recent reports indicate increased incidence of Clostridium botulinum infections, particularly among drug abusers and tissue allograft recipients. Botulinum toxin also has potential application in biochemical warfare. The neurotoxin-induced paralysis often requires mechanical ventilation with and without muscle relaxants. The authors investigated the long-term effects of botulinum toxin on muscle function, expression of nicotinic acetylcholine receptors (nAChRs), and their interaction with muscle relaxant, atracurium.
Methods: Rats (n = 30) were injected with varying doses (0.625, 2.5, and 10 U) of botulinum toxin into the tibialis muscle. Control animals (n = 9) received an equivalent volume of saline. At 128 days after injection, neuromuscular function, pharmacodynamics of atracurium, and nAChRs were evaluated.
Results: Nerve-evoked tensions, including tetanic tension and muscle mass, were decreased on the toxin-injected side in a dose-dependent manner relative to saline-injected controls as well as the contralateral side. Specific muscle tension and specific tetanic muscle tension (tensions/muscle mass) were not reduced. The ED10 of atracurium was reduced, the ED50 was unchanged, and the ED90 was increased in the highest (10-U) dose of toxin group. The atracurium plasma concentration to maintain a steady state 50% paralysis was significantly reduced in the 10-U toxin group. The nAChR concentrations in the tibialis muscle were significantly increased in a dose-dependent manner in all experimental groups. 相似文献