Caudal additives to ropivacaine in children: preservative free S-ketamine versus clonidine
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Journal Article↗
Biomedical subjects
F Borrelli
Publications and source records attributed to F Borrelli.
Contractile effect of (+)-glaucine in the isolated guinea-pig ileum.
The intestinal effects of (+)-glaucine [(S)-1,2,9,10-tetramethoxyaporphine] were studied using the guinea-pig ileum. (+)-Glaucine (10-300 microM) induced ileal contractions. The contraction was not affected by tetrodotoxin, atropine, hexamethonium, propranolol, naloxone, methysergide, N(G)-nitro-L-arginine methyl ester, SR141716A (a cannabinoid CB1 receptor antagonist) or SR140333 (a tackykinin NK1 receptor antagonist) plus SR48968 (a tackykinin NK2 antagonist). (+)-Glaucine-induced contraction was reduced by indomethacin, nordihydroguaiaretic acid or bisindolylmaleimide I and abolished by verapamil and nifedipine. These results suggest that (+)-glaucine-induced contraction involves activation of voltage-dependent Ca2+ channels and protein kinase C and could be mediated by the release of arachidonic acid metabolites.
Animals↗
The role of nitric oxide in aloe-induced diarrhoea in the rat.
The role of nitric oxide (NO) on aloe-induced diarrhoea was studied in the rat. Nine hours after oral administration, aloe produced diarrhoea at doses of 5 g kg(-1)(20% rats with diarrhoea) and 20 g kg(-1) (100% of rats with diarrhoea). Lower doses of aloe (0.1 and 1 g kg(-1) did not produce a diarrhoeal response. Pre-treatment (i.p.) of rats with the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME 2.5-25 mg kg(-1) reduced the diarrhoea induced by aloe (20 g kg(-1) 9 h after its oral administration. L-NAME (25 mg kg(-1)) also reduced the increase in faecal water excretion produced by aloe (20 g kg(-1). L-arginine (1500 mg kg(-1), i.p.), administered to rats pre-treated with L-NAME (25 mg kg(-1), drastically reduced the effect of L-NAME on diarrhoea and increase in faecal water excretion induced by aloe (20 g kg(-1). Given alone, L-arginine did not modify aloe-induced diarrhoea. Basal Ca2+ -dependent NO synthase activity in the rat colon was dose-dependently inhibited by aloe (0.1-20 g kg(-1)) and by aloin (0.1-1 g kg(-1)), the active ingredient of aloe. These results suggest that endogenous NO modulates the diarrhoeal effect of aloe.
Aloe↗
Defaecation, intestinal fluid accumulation and motility in rodents: implications of cannabinoid CB1 receptors.
We have studied the effect of SR141716A (0.1-5 mg/kg, i.p.), a cannabinoid CB, receptor antagonist, and WIN (0.1-5 mg/kg, i.p.), a cannabinoid receptor agonist, on acute defaecation and gastrointestinal transit in mice and on intraluminal fluid accumulation in the rat small intestine. SR141716A increased while WIN 55,212-2 decreased defaecation, gastrointestinal transit and fluid accumulation. A per se non-effective dose of SR141716A (0.3 mg/kg) counteracted the inhibitory effect of WIN 55,212-2 (1 mg/kg) on gastrointestinal functions studied. The effect of SR 141716 on both intestinal fluid accumulation in rats and gastrointestinal transit in mice was inhibited by atropine (1 mg/kg, i.p.), but not by hexamethonium (1 mg/kg, s.c.), SR140333 (20 microg/kg, i.p.) or SR48968 (20 microg/kg, i.p.), antagonists of NK1 and NK2 receptors, respectively. These results suggest that intestinal fluid accumulation and motility are inhibited by endogenous cannabinoid(s) acting at the cannabinoid CB1 receptors. This effect may be mediated by mechanisms involving muscarinic cholinoceptors.
Animals↗
Does senna extract promote growth of aberrant crypt foci and malignant tumors in rat colon?
Current evidence suggests that aberrant crypt foci (ACF) can be used to evaluate agents for their potential colon carcinogenic activity. The aim of the present study was to determine whether senna pod extract (SE) itself induces ACF and tumors in the rat colon or increases the development of ACF and tumors induced by azoxymethane (AOM). A daily administration of SE 10 mg/kg by mouth for 13-28 weeks produced a weak laxative effect but did not itself cause the appearance of ACF or tumors. The numbers of ACF and tumors induced by AOM were, however, increased by a dose of SE (100 mg/kg) able to induce chronic diarrhea over three months. These results suggest that SE does not cause the appearance of ACF or tumors in the rat colon nor does it have a promoting effect when given to rats at a dose that produces laxation (10 mg/kg), whereas a diarrhogenic dose (100 mg/kg) increases the appearance of tumors induced by AOM.
Animals↗
Biological characterization of recombinant human follicle stimulating hormone isoforms.
It has been established that follicle stimulating hormone (FSH) circulates in the bloodstream as a heterogeneous population of molecules. Individual FSH isoforms, while displaying identical amino acid sequences, differ in their extent of post-translational modification. As a result of these variations, the FSH isoforms exhibit differences in overall charge, degree of sialic acid or sulphate incorporation, receptor binding affinity and plasma half-life. Taking advantage of the fact that these forms can be separated from each other on the basis of their charge, we have evaluated in rats the metabolic clearance rates of the acidic [with an isoelectric point (pI) </=ISOdia</= 4.8] and the less acidic (pI > 4.8) isoforms of recombinant human FSH (rhFSH) obtained after chromatofocusing. The less acidic isoform group was found to have a faster clearance from the circulation in rats as compared with the acidic isoform group. This finding is in agreement with the lower bioactivity in vivo (as determined by the Steelman-Pohley assay) of the less acidic isoform group, compared with the acidic one. The mass spectra of the two groups of isoforms showed a difference in the sialic acid content thus highlighting the importance of these residues on the in-vivo activity of FSH. Conversely, when the two groups of isoforms were tested in vitro by using the Y1 human FSH receptor (Y1 hFSHR) assay and a reporter gene assay, no significant differences in the biological activities between these preparations were detected when test concentrations were based on mass.
Animals↗
Excitatory transmission to the circular muscle of the guinea-pig ileum: evidence for the involvement of cannabinoid CB1 receptors.
1. The effect of cannabinoid drugs has been investigated on cholinergic and non-adrenergic non-cholinergic (NANC) contractile responses to the circular smooth muscle of guinea-pig ileum elicited by electrical field stimulation (EFS). 2. The cannabinoid receptor agonist WIN 55,212-2 (1-1000 nM) and the putative endogenous ligand anandamide (0.1-100 microM) both produced a concentration-dependent inhibition of the cholinergic (9-57% and 1-51% inhibition) and NANC (9 55% and 2-57% inhibition) contractile responses. WIN 55,212-2 and anandamide did not modify the contractions produced by exogenous acetylcholine or substance P. 3. Apamin (30 nM), a blocker of Ca2+-activated K+ channels, reduced the inhibitory effect of WIN 55,212-2 on cholinergic, but not NANC, contractile response. NG-nitro-L-arginine methyl ester (100 microM), an inhibitor of nitric oxide synthase, or naloxone (1 microM), an opioid receptors antagonist, did not modify the inhibitory effect of WIN 55,212-2 on both cholinergic and NANC contractions. 4. The inhibitory effects of WIN 55,212-2 and anandamide on both cholinergic and NANC contractile response was competitively antagonized by the cannabinoid CB1 receptor antagonist SR 141716A (10-1000 nM). 5. In absence of other drugs, SR 141716A (1-1000 nM) enhanced cholinergic (1-45% increase) and NANC (2-38% increase) contractile responses elicited by electrical stimulation, but did not modify the contractions produced by acetylcholine or substance P. 6. It is concluded that activation of prejunctional cannabinoid CB1 receptors produces inhibition of cholinergic and NANC excitatory responses in the guinea-pig circular muscle. The inhibition of cholinergic (but not NANC) transmission involves activation of apamin-sensitive K+ channels. In addition, an endogenous cannabinoid ligand could inhibit cholinergic and NANC transmission in the guinea-pig ileal circular muscle.
Animals↗
Spinal anesthesia with clonidine and bupivacaine in young humans: interactions and effects on the cardiovascular system.
BACKGROUND: Clonidine, an alpha 2 agonist, is known to prolong the action of local anesthetics, and to provide a satisfactory analgesia; hypotension and bradycardia have been observed after its intrathecal administration. The aim of our study was to determine whether intrathecal administration of clonidine can reduce the dose of local anesthetic, and the effects of clonidine on the cardiovascular system, and on arousal level. METHODS: In a prospective, randomized study we evaluated 56 patients scheduled for minor surgical procedure (spermatic vein ligature) under unilateral spinal anesthesia with hyperbaric bupivacaine 1%. One half of patients received clonidine (105 micrograms) in addition to bupivacaine. Mean arterial pressure, heart rate were recorded baseline until 1 hour after surgery. Cardiac output, stroke volume, ejection fraction, systemic vascular resistance and left cardiac work were measured, by thoracic electric bioimpedance method, baseline until 1 hour after surgery. Sensory block, motor block and sedation level were measured at the beginning of anesthesia and for 6 hours after the end of surgery. RESULTS: In the clonidine treated group we did not observe variations of cardiovascular parameters; in the same group we did observe sensory block and motor block significantly prolonged, a higher sedation level and a significant postoperative analgesia. CONCLUSIONS: In summary, the addition of clonidine to hyperbaric bupivacaine seems to be particularly useful in unilateral spinal anesthesia, exerting minimal influence on haemodynamic parameters, and guaranting a satisfactory postoperative analgesia.
Adrenergic alpha-Agonists↗
NG-nitro-L-arginine methyl ester reduces senna- and cascara-induced diarrhoea and fluid secretion in the rat.
Senna (60 mg/kg orally) and cascara (800 mg/kg orally)-induced diarrhoea and net fluid secretion were studied in rats for a time period of 1-8 h. NG-Nitro-L-arginine methyl ester (L-NAME) (2.5-25 mg/kg i.p. twice, 15 min before and 4 h after laxative administration), an inhibitor of nitric oxide synthase, reduced the diarrhoeal response. This effect was counteracted by L-arginine (600 and 1500 mg/kg i.p. 15 min before laxative administration), the precursor of nitric oxide (NO). The senna- and cascara-stimulated fluid secretion was reduced by NG-nitro-L-arginine methyl ester 25 mg/kg i.p. (twice, 15 min before and 4 h after laxative administration), while the stereoisomer NG-nitro-D-arginine methyl ester (D-NAME) 25 mg/kg i.p. was without effect. These results suggest a possible involvement of NO in senna- and cascara-induced diarrhoea and fluid secretion.
Animals↗
Somatostatin-induced modulation of inflammation in experimental arthritis.
OBJECTIVE: To study the antiinflammatory effect of different doses of intraarticular somatostatin in experimental arthritis in rabbits. METHODS: Chronic arthritis was induced by a single injection of fibrin into the knee joint of rabbits previously sensitized to this antigen. The effects of sequential intraarticular injections of somatostatin into the rabbit knee, at doses of 500, 750, and 1,000 micrograms, were monitored by measuring knee joint circumferences and hematologic parameters. The measurements were compared with those obtained following use of triamcinolone acetonide and placebo. At the end of the experiments, the knee joints were examined histologically. RESULTS: Somatostatin treatment induced a statistically significant and dose-related reduction of knee joint swelling. This effect was shorter than that produced by triamcinolone acetonide; however, the antiinflammatory activity elicited by successive doses of triamcinolone acetonide declined both in extent and duration, while the effects of somatostatin remained unchanged at each successive treatment. Histopathologic observations showed that both somatostatin and triamcinolone acetonide reduced the inflammatory signs in the joint structures, although triamcinolone acetonide appeared to be more effective. CONCLUSION: These findings suggest that somatostatin exerts an antiinflammatory effect in this model of experimental arthritis and may represent a valid and safer alternative to corticosteroids for intraarticular therapy of arthritis.
Animals↗
Allergenic potential of gonadotrophic preparations in experimental animals: relevance of purity.
Local reactions have been frequently reported following repeated injections of human menopausal gonadotrophins (HMG) for the treatment of infertility. Also immunoglobulin (Ig) E-mediated systemic reactions have sporadically been observed. Since most HMG preparations contain significant amounts of non-hormonal urine-derived proteins, it was suggested that these contaminating proteins are responsible for the various allergic reactions. In order to verify this hypothesis, different human follicle stimulating hormone (HFSH) and HMG preparations (Metrodin and Pergonal from Ares-Serono, and Humegon from Organon), were compared with a highly purified preparation (Metrodin HP from Ares-Serono) for the frequency and severity of allergic reactions induced in laboratory animals. The occurrence of anaphylactic shock or related symptoms was studied in sensitized guinea-pigs. The production of specific IgE was evaluated in serum from mice sensitized with the test drugs by the induction of passive cutaneous anaphylaxis in rats. In both models, two different schedules of sensitization were used. Severe allergic reactions were found in 20 of 7% of the guinea-pigs receiving highly purified FSH (Metrodin HP) in the two schedules, respectively, compared to 90 and 88% with the other preparations. Similarly significantly lower IgE titres were induced by highly purified FSH in respect to the other preparations. It can be concluded that the elimination of contaminating proteins significantly reduces the allergenicity of urine-derived HFSH preparations.
Anaphylaxis↗
General pharmacology studies on recombinant human follicle stimulating hormone.
Follicle stimulating hormone (FSH) is a heterodimeric glycoprotein secreted by anterior pituitary cells. Its main actions are to lead ovarian follicles to maturation and to maintain spermatogenesis. Up to now the FSH preparations used in clinical practice (CAS 9002-68-0 and CAS 97048-13-0) have been purified from human postmenopausal urine. Only recently, a product was successfully obtained by recombinant-DNA technology, r-hFSH (Gonal-FTM). This recombinant protein is highly pure and has a very high specific activity. In view of its clinical use, this hormone has been submitted to an extensive panel of general pharmacology studies with the aim of defining its pharmacological profile and determine possible side effects not related to the main therapeutic action. Subcutaneous or intravenous doses of 5 to 500 IU/kg were assayed in several tests for their effects in vivo on various systems in different animal species. The substance under study was also tested in vitro on isolated guinea-pig ileum preparations at final concentrations of 0.05 to 2 IU/ml of bath. The results of this study showed that r-hFSH does not influence the general activity and behaviour of mice, as measured by the multidimensional Irwin's test. Similarly, the drug was not found to affect the normal body temperature in rats nor the locomotor activity in mice for as long as 7 h post-injection; in addition, it was not found to induce pharmacologically significant alterations of the cardiovascular and respiratory parameters in rats and dogs.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Effect of thymostimulin in models of cell-mediated and humoral autoreactivity and on T-dependent suppression.
To explore the therapeutic potential of the thymic hormone preparation thymostimulin (TS) in animal models of cell-mediated and humoral autoimmunity, its effects were investigated on experimental allergic encephalomyelitis in guinea pigs and on anti-erythrocytic autoantibody production in C57B1/6 mice. In both autoimmunity models, TS produced significant therapeutic effects in terms of proportion of diseased animals, disease severity and/or disease duration; however, both the TS dose and the time of treatment start relative to the disease-inducing stimulus critically influenced results. TS effects on the generation and expression of suppressive activity induced in C57B1/6 mice by a supraoptimal immunization with 10(10) SRBC were also examined. TS given after 10(10) SRBC did not influence the level of suppression, and the activity of effectors of suppression was not modified by this agent. Conversely, using a treatment protocol analogous to that effective in reducing murine autoantibody production, TS administration prior to 10(10) SRBC was associated with a significant increase in the subsequent generation of T-dependent, antigen-specific suppressive activity. These findings suggest that effects of TS on the development of suppressor cells may be involved in the activity of this agent in animal models of autoaggression.
Animals↗
The co-operative action of hyaluronidase and urokinase on the isoproterenol-induced myocardial infarction in rats.
The effects of the intravenous administration of hyaluronidase (HY; 2,500 IU/kg) and urokinase (UK; 20,000 and 40,000 IU/kg), alone or in combination, on the isoproterenol (ISP) induced myocardial infarction (MI) in rats, were studied. The severity of infarction was determined by measuring the levels of serum enzymes (CPK, GOT, LDH) and by evaluating the extent of the injured areas and the incidence of mortality. Plasma thromboxane B2 (TXB2) levels were also determined. All the treatments reduced the infarction area and the enzyme levels (increased by ISP) to a varying degree. However, a definite potentiating activity was obtained when HY was combined with the highest dose of UK. This combination was also capable of reducing the mortality rate. Finally, both HY and UK or the combined preparation brought the plasma TXB2 levels back to normal. These findings suggest the possibility of complementary activities of HY and UK in the treatment of experimental MI.
Animals↗
Sex-related toxicity of somatostatin and its interaction with pentobarbital and strychnine.
The intravenous LD50 of the hypothalamic tetradecapeptide somatostatin was determined in mice and rats of both sexes. It was found that somatostatin has a sex-related toxicity both in mice and rats. The interaction of low and high doses of peptide with the LD50s of two central nervous system (CNS) drugs, namely pentobarbital and strychnine, was also studied in male and female mice. Differential effects were observed as follows: a very low dose (0.1 mg/kg) of somatostatin does not affect the toxicity of these compounds, whereas the injection of 1 mg/kg of peptide increased pentobarbital toxicity and decreased the toxicity of strychnine. However, an increase in the toxicity of both substances was obtained with very high non-lethal doses of peptide (20 and 30 mg/kg, in female and male mice, respectively).
Animals↗
"In vitro" activity of urokinase on platelet function and on ADP degradation by vascular tissue.
The effects of urokinase on ADP breakdown by vessel-wall, platelet aggregation and the related prostaglandin system "in vitro" were investigated. It is confirmed that urokinase does not induce platelet aggregation both in humans and rabbits "in vitro". Conversely, in high concentrations, urokinase inhibits ADP-induced platelet aggregation in human and rabbit platelet-rich plasma. No effects were observed on rabbit platelet thromboxane A2 release and on rat vascular prostacyclin production, both measured by radioimmunoassay of thromboxane B2 and 6-keto-F1 alpha prostaglandin, respectively. Moreover, the incubation of urokinase with vascular endothelium resulted in an increased disappearance rate.
Adenosine Diphosphate↗
Activity ratio between antiprostacyclin and antiaggregating effects of acetylsalicylic acid, indometacin and ditazole.
The effects of acetylsalicylic acid (ASA) indometacin and ditazole on prostacyclin production from rabbit aortic rings were studied in comparison to their inhibiting activity on platelet aggregation. The result were expressed as the ratio between the drug dose inhibiting by 50% prostacycline production and the minimum oral antiaggregating dose. The following ratios were found: 2.4 for ASA, 7.3 for indometacin and 20.4 for ditazole.
Animals↗
Ex-ovo phospholipids as carriers of cortisol palmitate.
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Animals↗