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Medical Sciences	50%

Selected Abstracts

Behaviours of pulmonary sensory receptors during development of acute lung injury in the rabbit

EXPERIMENTAL PHYSIOLOGY, Issue 4 2007
Shuxin Lin
We tested the hypothesis that oleic acid-induced acute lung injury activates pulmonary nociceptors, that is, C fibre receptors (CFRs) and high-threshold A, fibre receptors (HTARs). Single-unit activity was recorded in the cervical vagus nerve and assessed before and after injecting oleic acid (75 ,l kg,1i.v.) into anaesthetized, open-chest, mechanically ventilated rabbits. Unit activities increased within seconds and peaked within a few minutes (from 0.3 ± 0.1 to 1.4 ± 0.9 impulses s,1 for CFRs and from 0.5 ± 0.1 to 1.7 ± 0.3 impulses s,1 for HTARs, both n= 8 and P < 0.05). These activities were sustained while pulmonary oedema developed and dynamic lung compliance decreased over the 90 min observation period. Activities in slowly adapting receptors and rapidly adapting receptors were also increased; however, their responsiveness to airway pressure stimulation decreased progressively. We conclude that pulmonary nociceptors are stimulated during acute lung injury. The dual nociceptor system, consisting of both non-myelinated CFRs and myelinated HTARs, may play an important role in the pathophysiological process of acute lung injury-induced respiratory responses. [source]

Fluid resuscitation from severe hemorrhagic shock using diaspirin cross-linked hemoglobin fails to improve pancreatic and renal perfusion

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2004
A. Pape
Background:, Fluid resuscitation from hemorrhagic shock is intended to abolish microcirculatory disorders and to restore adequate tissue oxygenation. Diaspirin cross-linked hemoglobin (DCLHb) is a hemoglobin-based oxygen carrier (HBOC) with vasoconstrictive properties. Therefore, fluid resuscitation from severe hemorrhagic shock using DCLHb was expected to improve perfusion pressure and tissue perfusion of kidneys and pancreas. Methods:, In 20 anesthetized domestic pigs with an experimentally induced coronary stenosis, shock (mean arterial pressure 45 mmHg) was induced by controlled withdrawal of blood and maintained for 60 min. Fluid resuscitation (replacement of the plasma volume withdrawn during hemorrhage) was performed with either 10% DCLHb (DCLHb group, n = 10) or 8% human serum albumin (HSA) oncotically matched to DCLHb (HSA group, n = 10). Completion of resuscitation was followed by a 60-min observation period. Regional blood flow to the kidneys and the pancreas was measured by use of the radioactive microspheres method at baseline, after shock and 60 min after fluid resuscitation. Results:, All animals (10/10) resuscitated with DCLHb survived the 60-min observation period, while 5/10 control animals died within 20 min due to persisting subendocardial ischemia. In contrast to HSA survivors, pancreas and kidneys of DCLHb-treated animals revealed lower total and regional organ perfusion and regional oxygen delivery. Renal and pancreatic blood flow heterogeneity was higher in the DCLHb group. Conclusion:, DCLHb-induced vasoconstriction afforded superior myocardial perfusion, but impaired regional perfusion of the kidneys and the pancreas. [source]

Anxiolytic properties of Piper methysticum extract samples and fractions in the chick social,separation,stress procedure

PHYTOTHERAPY RESEARCH, Issue 3 2003
Matt W. Feltenstein
Abstract Piper methysticum extract (Kava kava) possesses anxiolytic properties. However, it is unknown whether these effects are best predicted by total kavalactone content or by one or more of its primary kavalactone constituents. Using the chick social separation-stress procedure as an anxiolytic bioassay, P. methysticum samples containing 12.8,100.0% total kavalactones (Exp. 1) and fractions containing 1,6 kavalactones of varying concentrations (0.1,67.5%; Exps. 2,3) were screened for activity and compared against a 5.0 mg/kg dose of chlordiazepoxide (CDP; Exp. 3). Eight-day-old chicks received IP injections of either vehicle or test compounds 30 min before being placed in the presence of two conspeci,cs or in isolation for a 3 min observation period. Dependent measures were ventral recumbency latency (sedation), distress vocalizations, and a measure of stress-induced analgesia (in Exps. 1 and 2 only). P. methysticum extract samples attenuated distress vocalizations in a concentration-dependent manner. The P. methysticum fraction that contained the highest concentration of dihydrokavain attenuated distress vocalizations in a manner equivalent to that of CDP. The extract samples and fractions that possessed anxiolytic properties did not possess the sedative properties found in CDP. Collectively, these ,ndings suggest that dihydrokavain may be necessary and suf,cient in mediating the anxiolytic properties of P. methysticum extract. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Synthesis and Antidepressant Evaluation of Five Novel Heterocyclic Tryptophan-Hybrid Derivatives

ARCHIV DER PHARMAZIE, Issue 5 2010
Gamal A. Elmegeed
Abstract This study aimed at evaluating the reactivity of L -Tryptophan (TRP) 1 towards various chemical reagents to produce new bi- and tri-heterocyclic systems providing basic pharmacological activities. Indol-3-yl hydroxyoxazol-2-yl acetonitrile derivatives 5 and 6, indol-3-yl-hydroxyoxazol-2-yl-1,2,4-triazine derivatives 8 and 9, indol-3-yl-hydroxyoxazol-2-yl-aminopyrazole derivatives 11a, b, and indol-3-yl-hydroxyoxazol-2-yl-aminoisoxazole derivative 12 were synthesized via straightforward and efficient methods. The structures were characterized by spectral data (IR, 1H-NMR, 13C-NMR, and MS) and the purity was ascertained by microanalysis. Also, this work was extended to study the potential role of the novel synthesized TRP derivatives 5, 6, 9, 11a, and 12 as antidepressant and sedative agents in comparison with TRP. All compounds showed significant antidepressant activity in the forced-swimming test at two doses (50 or 100 mg/kg). Also, all tested compounds (at 50 or 100 mg/kg) produced a significant decrease in locomotor activity of mice during a 30 min observation period. The most potent antidepressant and sedative effect was produced by the tri-heterocyclic compounds 9 and 12, followed by 11a and TRP. [source]