[In-phase and out-of-phase single-shot magnetization-prepared gradient recalled echo: description and optimization of technique at 1.5 T]. / Secuencia de disparo único eco de gradiente en fase y fase opuesta con preparación de la magnetización: descripción y optimización de la técnica con equipo de 1,5 T.

PURPOSE: To implement in-phase and out-of-phase (IP/OP) techniques with Magnetization-Prepared Gradient Recalled Echo (MP-GRE) and to evaluate the feasibility and diagnostic image quality among pre and post-optimized MP-GRE sequences, including patients unable to cooperate with breath-hold requirements. MATERIALS AND METHODS: Institutional review board approval with waiver of informed consent was obtained for this HIPAA-compliant retrospective study. Two groups of patients were included in the study, before and after optimization of MP-GRE parameters, with seventy-three (24 noncooperative/49 cooperative) and sixty-four (22 noncooperative/42 cooperative) consecutive patients, respectively. The motion-insensitive sequence used in this study was a single-shot 2D MP-GRE. Two radiologists qualitatively evaluated the sequences to identify the presence of phase cancellation artifact in OP images and to determine image quality, extent of artifacts (respiratory ghosting, bounce-point artifact, spatial misregistration and pixel graininess) and lesion conspicuity on the various sequences. The ability to visually detect liver steatosis and fatty adrenal adenomas was evaluated. Qualitative analyses were compared using the Wilcoxon and Mann-Whitney tests. RESULTS: There were statistically significant differences between all MP-GRE sequences concerning phase cancellation artifact (P<.0001) which was present in MP-GRE OP sequences and negligible to absent in the pre (IP1) and post-optimized (IP2) MP-GRE IP sequences, respectively, in all patients. Bounce point artifacts were significantly more pronounced in MP-GRE IP1 (P<.0001). Spatial misregistration was slightly more prominent in noncooperative patients with MP-GRE IP2 (P=.0027). MP-GRE OP and MP-GRE IP2 showed significantly higher overall image quality (P<.0001). MP-GRE sequences subjectively identified hepatic steatosis (n=20) and adrenal adenomas (n=5) based on signal loss from IP to OP sequence. CONCLUSION: Single shot IP/OP MP-GRE is feasible and allows motion resistant imaging with adequate diagnostic image quality. This technique is able to provide IP and OP information in patients unable to suspend respiration.

Antinociceptive properties of extracts of new species of plants of the genus Phyllanthus (Euphorbiaceae).

The hydroalcoholic extract (HE) of the four new species of Phyllanthus, given intraperitoneally, produced significant inhibition of acetic acid-induced abdominal constrictions, with mean ID(50) values of 0.3, 1.8, 7.4 and 26.5 mg/kg for Phyllanthus amarus, Phyllanthus orbiculatus, Phyllanthus fraternus and Phyllanthus stipulatus, respectively. In the formalin test, the four species of Phyllanthus, also produced graded inhibition against both phases of formalin-induced licking, being more active in relation of the late phase. The HE of the Phyllanthus species elicited significant inhibition of the capsaicin-induced neurogenic pain, with mean ID(50) values of 8.9, 6.7, >30 and approximately 30 mg/kg for P. amarus, P. fraternus, P. stipulatus and P. orbiculatus, respectively. Given orally all HE of the Phyllanthus species were less potent and efficacious than when given by intraperitoneally. Results of the present study extend previous data and indicate that all extracts of Phyllanthus plants so far studied exhibit pronounced antinociception when assessed in chemical models of nociception, namely acetic acid-induced writhing, and formalin and capsaicin-induced licking.

Oral antinociception and oedema inhibition produced by NPC 18884, a non-peptidic bradykinin B2 receptor antagonist.

This study investigates the antinociceptive and the oedema inhibition properties of the novel non-peptide bradykinin (BK) B2 receptor antagonist, NPC 18884. Given by i.p. or p.o. routes NPC 18884 produced graded and long-lasting (at least 2.5h and 5.0h, respectively, for i.p. and p.o. administration) inhibition of acetic acid-induced abdominal constrictions in mice, with mean ID50 values of 8.3 nmol/kg and 439.9 nmol/kg. NPC 18884 also inhibited kaolin-induced abdominal constrictions (44+/-9% and 48+/-3% of inhibition, for i.p. and p.o. routes, respectively). Given by i.p. or p.o. routes NPC 18884 attenuated both phases of formalin-induced licking, as well as formalin-induced oedema formation. At similar doses NPC 18884 produced significant inhibition of capsaicin-induced nociception. NPC 18884, like HOE 140 given i.p., prevented the nociception caused by BK with mean ID50 values of 0.85 nmol/kg and 0.44 nmol/kg, respectively. Given orally NPC 18884, but not HOE 140, caused graded inhibition of BK-induced nociception (mean ID50 value of 50 nmol/kg). In rats, NPC 18884 given i.p. prevented BK and carrageenan-induced hyperalgesia (mean ID50 values of 6 nmol/kg and 13 nmol/kg), without affecting the hyperalgesia induced by des-Arg9-bradykinin (DABK) or by prostaglandin E2 (PGE2). NPC 18884 given i.p. inhibited the mouse paw oedema induced by tyrosine8-bradykinin or by carrageenan, but had no effect on DABK-induced oedema in mice pre-treated with Escherichia coli endotoxin, or that induced by PGE2. Thus, the novel non-peptide BK B2 receptor antagonist NPC 18884 produces rapid onset, potent and relatively long-lasting oral antinociceptive and oedema inhibition properties. The anti-BK actions of NPC 18884 are quite selective towards the BK B2 receptor-mediated responses.

The involvement of K+ channels and Gi/o protein in the antinociceptive action of the gallic acid ethyl ester.

The anti-hyperalgesic action, antinociception, and also the possible mechanisms involved in the action of gallic acid ethyl ester (GAEE) isolated from the aerial part of Phyllanthus urinaria, have been investigated in different models of chemical, mechanical and thermal nociception in mice and rats. GAEE given by intraperitoneal (i.p.), oral (p.o.), intrathecal (i.t.) or by intracerebroventricular (i.c.v.) routes produced dose-related antinociception when assessed against chemical nociception in mice. GAEE significantly inhibited the hyperalgesia induced by bradykinin or substance P in rat paw, but did not affect the hyperalgesia caused by carrageenan or prostaglandin E2. Furthermore, GAEE, in contrast to morphine, was completely ineffective in the hot-plate test in mice. The antinociception produced by GAEE (i.p.) in the formalin test was significantly reversed by i.c.v. treatment of animals with pertussis toxin and by i.t. administration of K+ channel blockers such as apamin, charybdotoxin or glibenclamide, but not by tetraethylammonium. In contrast, GAEE (i.p.) antinociception was unaffected by i.p. treatment of animals with naloxone or by nitric oxide precursor, L-arginine, and this action was not secondary to its anti-inflammatory effect, nor was it associated with non-specific effects such as muscle relaxation or sedation. Thus, GAEE produces dose-dependent and pronounced systemic, spinal and supraspinal antinociception in mice, probably via activation of K + channels and by a Gi/o pertussis toxin-sensitive mechanism.

Systemic treatment with Mycobacterium bovis bacillus Calmette-Guérin (BCG) potentiates kinin B1 receptor agonist-induced nociception and oedema formation in the formalin test in mice.

This study investigates the effect and some of the mechanisms involved following systemic treatment of mice with Mycobacterium bovis bacillus Calmette-Guérin (BCG) (1 dose per animal containing 6.4 x 10(4) colony-forming units (CFu) 20-60 days beforehand) on modulation of the kinin B1 receptor agonist-induced nociception and oedema formation in the formalin test. Intraplantar (i.p.l.) co-injection of des-Arg9-bradykinin (4-32 nmol/paw) or des-Arg10-kallidin (1-15 nmol/paw), together with sub-maximal concentrations of formalin (0.01 or 0.5%), potentiated (P < 0.01) both pain phases and the paw oedema caused by formalin in animals pre-treated with saline. However, when animals were pre-treated with BCG, the dose-response curves for both B1 agonists were shifted 2 to 8-fold to the left. These B1-mediated effects peaked at 30-45 days after BCG treatment and were still elevated at 60 days after BCG injection. The pain response and oedema formation caused by i.p.l. co-injection of des-Arg9-bradykinin, together with formalin in BCG-pre-treated animals, were dose-dependently antagonised by i.p.l. co-injection of the B1 antagonist des-Arg9[Leu8]bradykinin (1-15 nmol/paw), but were not affected by the B2 antagonist Hoe 140 (10 nmol/paw). The i.p.l. co-injection of tyrosine8-bradykinin (a B2 agonist, 3-15 nmol/paw) with formalin (0.01 or 0.5%) potentiated the pain response and paw oedema in BCG and saline-pre-treated animals to the same extent (P < 0.01). The actions caused by tyrosine8-bradykinin were antagonised by Hoe 140, while des- Arg9[Leu8]bradykinin (10 nmol/paw) had no effect. Dexamethasone (0.5 mg/kg, s.c.), given every 24 h, from day 0 to 30-45, inhibited significantly the potentiation of nociceptive response and oedema formation caused by i.p.l. co-injection of formalin plus des-Arg9-bradykinin, while indomethacin (2 mg/kg, i.p.) or phenidone (30 mg/kg, i.p.), given 1 h prior, caused less inhibition. These data show that the long-term systemic treatment of mice with BCG produced dose-related potentiation of B1 receptor agonist-mediated nociception and oedema formation, without affecting similar responses caused by the B2 receptor agonist tyrosine8-bradykinin. Thus, systemic treatment of mice with BCG induces upregulation of B1 receptors, without affecting B2-mediated responses, by a mechanism that seems to be secondary to cytokine release.

Anti-hyperalgesic effect of an ethanolic extract of propolis in mice and rats.

Propolis, or bee glue, which contains a complex mixture of secondary metabolites, has long been used in many countries for the management of several diseases. The purpose of this study was to evaluate, by means of several pharmacological models, the anti-hyperalgesic effect of propolis collected in the south of Brazil. The abdominal constrictions induced in mice by intraperitoneal injection of acetic acid (0.6%), kaolin (50 mg kg-1) or zymosan (40 mg kg-1) were inhibited to different extents by an extract of propolis (1-60 mg kg-1) administered intraperitoneally 30 min earlier; mean ID50 (concentrations resulting in 50% inhibition) values were 2.7, 10.8 and 10.7 mg kg-1, respectively, and maximum inhibition was 58 +/- 5, 57 +/- 10 and 51 +/- 5%, respectively. Given orally (25-200 mg kg-1, 1h previously) propolis also inhibited the abdominal constrictions induced by acetic acid (maximum inhibition 43 +/- 5%). When injected intraperitoneally (3-60 mg kg-1, 30 min previously), propolis attenuated both the neurogenic (first phase) and inflammatory (second phase) pain responses and paw oedema caused by intraplantar injection of formalin (2.5%); maximum inhibition was 32 +/- 5, 43 +/- 6 and 19 +/- 2%, respectively. Oral administration of propolis (25-200 mg kg-1, 1 h previously) inhibited both phases and reduced the oedema formation associated with the second phase of the formalin test (maximum inhibition 22 +/- 5, 33 +/- 6 and 26 +/- 3%) and extract of propolis (3-30 mg kg-1 i.p. or 25-100 mg kg-1 p.o., respectively 30 min and 1 h previously) significantly inhibited capsaicin-induced pain with maximum inhibition of 39 +/- 8 and 41 +/- 8%, respectively. When assessed in the Randall-Sellito test of pain, the extract of propolis (3-30 mg kg-1, i.p., 30 min previously) significantly reversed the hyperalgesia induced by intraplantar injection of bradykinin (3 nmol per paw) in rats (P < 0.01). In contrast with morphine the extract of propolis (< or = 100 mg kg-1, 30 min previously) was ineffective when assessed in the tail-flick and hot-plate thermal assays. Naloxone (5 mg kg-1 i.p.) reversed (P < 0.01) the effect of morphine (5 mg kg-1 s.c.) by 70 and 94% respectively in the first and second phases of the formalin test, but did not interfere with the analgesic effect of propolis (10 mg kg-1 i.p., 30 min previously). These results show that ethanolic extract of propolis, given systemically, has significant anti-hyperalgesic action when assessed in chemical, but not thermal, models of nociception in mice and rats. Its analgesic action seems to be unrelated to release or activation of the opioid system.

Antinociceptive properties of the hydroalcoholic extract and preliminary study of a xanthone isolated from Polygala cyparissias (Polygalaceae).

Polygala cyparissias (Polygalaceae) grows abundantly on Brazil's Atlantic coast, belonging to the typical underbrush vegetation of dunes and have been used in folk medicine for treatment of several diseases, such as disturbances of bowel and kidney. The hydroalcoholic extract of P. cyparissias (HE, 3 to 60 mg kg(-1), i.p. or 25 to 200 mg kg(-1), p.o.) produced significant and graded inhibition of acetic acid-induced abdominal constrictions, with mean ID50 values of 6 and 72 mg kg(-1), respectively. The HE (at this same range of doses) also produced dose-related inhibition of both the early and the late phase of formalin-induced licking. The calculated mean ID50 values for the early phase were: >60 and >200 mg kg(-1), while for the late phase they were 11 and 101 mg kg(-1), respectively, by i.p. and p.o. routes. The HE also caused dose-related inhibition of formalin-induced edema formation (P<0.01). The HE (3 to 60 mg kg(-1), i.p. or 50 to 200 mg kg(-1), p.o.) produced significant and dose-related inhibition of the neurogenic nociception caused by topical injection of capsaicin, with mean ID50 values of 12 and 71 mg kg(-1), respectively. Given orally, the HE (50 to 200 mg kg(-1)) prevented in a dose-dependent manner, bradykinin (3 nmol/paw) and substance P (10 nmol/paw)-induced hyperalgesia in the rat paw, with mean ED50 values of 122 and 121 mg kg(-1), respectively, but was ineffective in the hot-plate model of nociception. The antinociception caused by the HE, in contrast to that of morphine (5 mg kg(-1), s.c.), was not reversed by naloxone (5 mg kg(-1), i.p.) when assessed in the acetic acid writhing test. The HE, at antinociceptive doses, did not affect motor coordination of animals when assessed in the rota-rod model. The xanthone isolated from P. cyparissias, identified as 1,7-dihydroxy-2,3-dimethoxy xanthone (0.3 to 30 mg kg(-1), i.p.), produced dose-related inhibition of acetic acid-induced abdominal constriction, with mean ID50 value of 1.5 mg kg(-1). These data show that the active principle(s) present in the HE of P. cyparissias, elicited pronounced antinociception when assessed by i.p. or p.o. routes, against both inflammatory and neurogenic nociception, and was able to prevent bradykinin and substance P-induced hyperalgesia. Its precise mechanism of action still remains unclear.

Antioedematogenic and antinociceptive actions of NPC 18521, a novel bradykinin B2 receptor antagonist.

The novel pseudopeptide bradykinin B2 receptor antagonist containing the 1,3,8-triazaspiro[4,5]decan-4-one ring system, NPC 18521 (D-Arg-Arg-[1,3-phenyl,8-triazaspiro[4,5]-decane-4-one-3-acetyl]-S er-D -tetrahydroisoquinolinyl-octahydroindolinyl-Arg) (10 and 30 nmol/kg, i.p.), given 30 min prior, produced significant and long-lasting inhibition of rat paw oedema induced by bradykinin (3 nmol/paw) and carrageenan (300 micrograms/paw), without affecting the oedema induced by the selective bradykinin B1 receptor agonist, des-Arg9-bradykinin, in rats pretreated with Escherichia coli endotoxin. In contrast, when injected locally into the rat or mouse hindpaw, NPC 18521 (1-100 nmol) elicited dose-related oedema formation. This effect was almost completely blocked by cyproheptadine (20 mg/kg, i.p.) or by compound 48/80 (12 micrograms/paw), but was unaffected by Hoe 140 (D-Arg-[Hyp5,Thi5,Tic7,Oic8]bradykinin). NPC 18521 (0.3-10 nmol/kg, i.p.) produced significant inhibition of acetic acid, acetylcholine and kaolin- but not zymosan-induced abdominal constrictions in mice. The calculated mean ID50 values for these effects were 0.84, 0.46 and 0.55 nmol/kg, respectively. The antinociceptive action of NPC 18521 (3 nmol/kg, i.p.) had a rapid onset (15 min) and lasted for up to 120 min. Given topically (0.01-0.3 nmol), NPC 18521 produced significant attenuation of both the early and the late phase of the formalin-induced licking, as well as formalin-induced oedema formation. In addition, NPC 18521 given both systemically or topically, produced significant inhibition of the neurogenic nociception caused by topical injection of capsaicin. Given topically in the rat paw, NPC 18521 (10 nmol) caused marked hyperalgesia, an effect which was completely prevented by cyproheptadine (20 mg/kg, i.p.), but was unaffected by Hoe 140 (3 nmol/kg, i.p.). Given intraperitoneally, 30 min prior, NPC 18521 (3-30 nmol/kg) like Hoe 140 (1-10 nmol/kg) prevented, in a dose-dependent manner, bradykinin (3 nmol/paw)-induced hyperalgesia with mean ID50 values of 13.16 and 1.36 nmol/kg, respectively. Thus, the novel pseudopeptide bradykinin B2 receptor antagonist, NPC 18521, has an effect with rapid onset, and produces potent and relatively long-lasting antioedematogenic and antinociceptive properties. However, in contrast to Hoe 140, given locally into the hindpaw, NPC 18521 elicited marked oedema formation and hyperalgesia, an effect which seems to be secondary to mast cell degranulation and histamine and/or serotonin release. Finally, the anti-bradykinin actions of NPC 18521 are quite selective towards the bradykinin B2 receptor-mediated responses.

Chemical and pharmacological studies of Phyllanthus caroliniensis in mice.

The aim of this study was to isolate and characterize the constituents of the hydroalcoholic extract (HE) of the leaves, stems and roots from P. caroliniensis, and also to evaluate the preliminary antinociceptive action of the HE and purified compounds in mice. Phytosterols, quercetin, gallic acid ethyl ester and geraniin were identified in P. caroliniensis on the basis of 1H and 13C NMR spectral data and by mixed co-TLC and co-HPLC injection with authentic samples. The HE of P. caroliniensis (10-100 mg kg-1, i.p.) inhibited, in a dose-related manner, acetic acid-induced abdominal constrictions in mice, with a mean ID50 value of 23.7 mg kg-1. In the formalin test, the HE given intraperitoneally (1-30 mg kg-1) or orally (25-600 mg kg-1) caused graded inhibitions of both the neurogenic (first phase) and the inflammatory response (late phase) of formalin-induced licking. The HE was 54-fold more effective in inhibiting the late phase than it was in inhibiting the first phase of the formalin test, with mean ID50 values of 3.6 and 196.4 mg kg-1, respectively. The HE failed, however, to affect the oedematogenic response associated with the late phase of formalin-induced pain. In addition, the reference drug, aspirin, given intraperitoneally (1-100 mg kg-1) or orally (100-600 mg kg-1), caused significant inhibition of the late but not the first phase of the formalin test. Pharmacological analysis also revealed that quercetin, gallic acid ethyl ester and a semi-purified fraction of flavonoids (1-100 mg kg-1, i.p.) exhibited graded and significant antinociception against acetic acid-induced abdominal constriction. The mean ID50 values (mg kg-1) for these effects were: 18.8, 34.7 and 5.3, respectively. It is concluded that quercetin, gallic acid ethyl ester and some as yet unidentified flavonoids might account for the antinociceptive action reported for the HE of P. caroliniensis.