Biomedical subjects

G De Nucci

Publications and source records attributed to G De Nucci.

At least 19 recordsLinked to original sources

PubMed2006

Protective effect of prior physical conditioning on relaxing response of corpus cavernosum from rats made hypertensive by nitric oxide inhibition.

The aim of this work was to evaluate the influence of run training on the responsiveness of corpus cavernosum (CC) from rats made hypertensive by treatment with nitric oxide (NO) synthesis inhibitor. Wistar rats were divided into sedentary control (C-SD), exercise training (C-TR), N(omega)-nitro-L-arginine methyl ester (L-NAME) sedentary (LN-SD) and L-NAME trained (LN-TR) groups. The run training program consisted in 8 weeks in a treadmill, 5 days/week, each session lasted 60 min. L-NAME treatment (2 and 10 mg/rat/day) started after 4 weeks of prior physical conditioning and lasted 4 weeks. Concentration-response curves were obtained for acetylcholine (ACh), sodium nitroprusside (SNP), sildenafil and BAY 41-2272. The effect of electrical field stimulation (EFS) on the relaxations responses of CC was evaluated. Run training prevented the arterial hypertension induced by L-NAME treatment (LN-SD: 135+/-2 and 141+/-2 mm Hg for both doses of L-NAME) compared to LN-SD groups (154+/-1 and 175+/-2 mm Hg, for 2 and 10 mg of L-NAME, respectively). Run training produced an increase in the maximal responses (E(max)) of CC for ACh (C-SD: 47+/-3; C-TR: 52+/-1; and LN-TR: 53+/-3%) and SNP (C-SD: 89+/-1; C-TR: 98+/-1; and LN-TR: 95+/-1%). Both potency and E(max) for ACh were reduced in a dose of 10 mg of L-NAME, and run training restored the reduction of E(max) for ACh. No changes were found for BAY 41-2271 and sildenafil. Relaxing responses to EFS was reduced by L-NAME treatment that was restored by prior physical conditioning. In conclusion, our study shows a beneficial effect of prior physical conditioning on the impaired CC relaxing responses in rats made hypertensive by chronic NO blockade.

Acetylcholine↗

PubMed2006

In vitro mutagenicity of anti-inflammatory parsalmide analogues PA7, PA10, and PA31 triggered by biotransformation into hydroxy derivatives.

In this study, the mutagenicity of the anti-inflammatory parsalmide [5-amino-N-butyl-2-(2-propynyloxy)-benzamide] analogues PA7 [5-amino-N-butyl-2-cyclohexyloxy-benzamide], PA10 [5-amino-N-butyl-2-phenoxy-benzamide] and PA31 [5-amino-N-butyl-2-(p-tolyloxy)-benzamide] was determined by an Ames Salmonella assay. The experiments were performed by preincubating the compounds in the absence and presence of a post-mitochondrial fraction (S9) of rat liver homogenate from phenobarbital/beta-naphtoflavone treated rats. No mutagenic effect was observed after direct testing (no S9 added) in Salmonella typhymurium strains TA98, TA100, TA102, TA1535 and TA1537. However, in the presence of S9, the test substances triggered mutagenic responses in strains TA100 and TA98. PA31 presented the strongest mutagenic potential. The reversion rates in the presence of PA31 were about 2-19 fold higher than spontaneous mutation rates. In the presence of PA7, the reversion increased 2-14-fold over spontaneous rates. While PA10 showed a relatively mild mutagenic potential, as the number of revertants did not exceed 2.5 times the number of spontaneous mutations. Mass spectrometric analysis of the in vitro biotransformation showed that S9 converted (%), regioselectively, PA7 (19%), PA10 (7%) and PA31 (12%) into hydroxy-derivatives.

Animals↗

PubMed2006

A phase I trial of the bombesin/gastrin-releasing peptide (BN/GRP) antagonist RC3095 in patients with advanced solid malignancies.

Bombesin/gastrin-releasing peptides (BN/GRP) were shown to bind selectively to cell surface receptors, stimulating the growth of various types of malignancies in murine and human models. The novel BN/GRP synthetic receptor antagonist, RC-3095, was able to produce long-lasting tumor regressions in murine and human tumor models in vitro and in vivo. Animal toxicology studies showed no detectable organ toxicity apart from local irritation at the injection site. The purpose of this study was to determine the safety and feasibility of the administration of RC-3095 by daily subcutaneous injections in patients with advanced and refractory solid malignancies. Twenty-five patients received RC-3095 once or twice-daily at doses ranging from 8 to 96 ug/kg. Dose was escalated in groups of 3-5 patients per dose level. The only toxicity observed was local discomfort in the injection site at the highest doses. A single dose administration of RC-3095 at the highest dose level (96 ug/kg) was tested in a clearly hypergastrinemic individual with the Zollingen-Ellison syndrome and produced a decrease in plasma gastrin down to 50% of basal levels in 6 h. There was no objective tumor responses in patients included in the study. A short-lasting minor tumor response was observed in a patient with a GRP-expressing progressive medullary carcinoma of the thyroid. Due to problems with the analytical method, plasma pharmacokinetic data was obtained only from two patients included at the highest dose level. In these patients, RC-3095 reached plasma concentrations >100 ng/mL for about 8 h, which were within therapeutic levels on the basis of prior data obtained in mice and rats. The plasma elimination half-life was between 8.6-10.9 h. Due to the occurrence of local toxicity at the injection site, the dose escalation procedure could not be fully evaluated up to a maximum tolerated dose. Thus, a recommended dose of RC-3095 for Phase II trials could not be clearly established. Considering the novelty of its mechanism of action and impressive preclinical anti-tumor activity, further studies exploiting new formulations of RC-3095 for human use, such as slow-release preparations, and analogues with a more favorable pharmacokinetics are warranted.

Adult↗

PubMed2006

Comparative bioavailability of two ramipril formulations after single-dose administration in healthy volunteers.

OBJECTIVE: To assess the bioequivalence of a ramipril 5 mg tablet formulation (ramipril test formulation from Laboratórios Biosintética Ltda (Sao Paulo, Brazil) and Triatec from Aventis Pharma (Sueano, Brazil) standard reference formulation) in 26 healthy volunteers of both sexes. METHODS: The study was conducted using an open, randomized, 2-period crossover design with a 2-week washout interval. Plasma samples were obtained over a 36-hour period. Plasma ramipril and ramiprilat concentrations were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reaction monitoring (MRM). From the ramipril and ramiprilat plasma concentration vs. time curves, the following pharmacokinetic parameters were obtained: AUClast, AUCinf and Cmax. RESULTS: The limit of quantification was 0.2 ng x ml(-1) and 1.0 ng x ml(-1) for ramipril and ramiprilat, respectively. The geometric means and 90% confidence intervals (CI) for Ramipril/Triatec and Ramiprilat/Triatec percent ratios were: 104.69% (90% CI = 93.21-117.59%) for Cmax, 102.49% (90% CI = 92.76-113.24%) for AUClast, 103.60% (90% CI = 93.56 114.73%) for AUCinf, 108.48% (90% CI = 98.86-119.03%) for Cmax, 105.88% (90% CI = 101.55-110.39%) for AUClast, 97.30% (90% CI = 90.17-104.99%) for AUCinf, respectively. CONCLUSION: Since the 90% CI for AUClast, AUCinf and Cmax ratios were within the 80-125% interval proposed by the U.S. FDA, it was concluded that the ramipril formulation produced by Laboratórios Biosintética Ltda is bioequivalent to the Triatec formulation in both rate and extent of absorption.

Administration, Oral↗

PubMed2006

Comparative bioavailability of two losartan formulations in healthy human volunteers after a single dose administration.

OBJECTIVE: To compare the bioavailability of two potassic losartan immediate release tablet (50 mg) formulations (Losartan from Laboratórios Cristália Ltd., Brazil, as a test formulation and Cozaar from Merck Sharp & Dohme Farmacêutica Ltd., Brazil, as a reference formulation) in 25 volunteers of both sexes. MATERIAL AND METHODS: The study was conducted in an open, randomized, 2-period crossover design and a 1-week washout period. Plasma samples were obtained over a 24-hour interval. The concentrations of losartan and its active metabolite losartan acid were analyzed by combined reversed phase liquid chromatography and tandem mass spectrometry (LC-MS-MS) with negative ion electrospray ionization using a selected ion monitoring method. From the losartan and losartan acid plasma concentrations vs. time curves the following pharmacokinetic parameters were obtained: AUClast, AUC0-inf and Cmax. RESULTS: The geometric mean and respective 90% confidence interval (CI) of Losartan/Cozaar losartan percent ratios were 92.9% (82.2-105.0%) for Cmax, 99.0% (92.5-105.9%) for AUClast, and 99.1% (92.7-105.8%) for AUC0-inf. Furthermore, the geometric mean and respective 90% CI of Losartan/Cozaar losartan acid percent ratios were 98.5% (91.5-106.0%) for Cmax, 97.9% (93.3 102.7%) for AUClast, and 98.1% (93.6-102.9%) for AUC0-inf. CONCLUSION: Since the 90% CI for Cmax, AUClast and AUC0-inf were within the 80-125% interval proposed by the US Food and Drug Administration, it was concluded that the potassic losartan immediate release 50 mg tablet was bioequivalent to the Cozaar immediate release 50 mg tablet, according to both the rate and extent of absorption. While there were no significant differences in the bioequivalence assessed by either losartan or losartan acid, future bioequivalence studies on losartan may be performed by quantifying losartan alone as the parent compounds are more discriminative.

Adult↗

PubMed2005

A bioequivalence study of citalopram based on quantification by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry.

OBJECTIVE: The aim of this study was to compare the bioavailability of two citalopram formulations (citalopram from Eurofarma Laboratórios Ltda., as the test formulation, and cipramil from Schering-Plough, Brazil, as the reference formulation) in healthy volunteers. METHODS: The study had an open, randomized, two-period crossover design with a two-week washout interval between doses. The samples were obtained over a 168-hour interval after each oral administration of citalopram (one 20 mg tablet of each formulation). The analyte and the internal standard were extracted from plasma using diethylether: dichloromethane (70 : 30, v/v) and the extracts were analyzed by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry. Chromatography was done isocratically using a Genesis C8 analytical column (4 microm, 2.1 mm i.d. x 100 mm). The method had a chromatographic run time of three minutes and a linear calibration curve over the range of 0.5 - 200 ng x ml(-1) (r2 > 0.999887). The limit of quantification was 0.5 ng x ml(-1). RESULTS: The geometric mean and 90% confidence intervals (CI) for the citalopram/cipramil ratio were 98.28% (94.24 - 102.49%) for AUClast, 96.44% (90.20 - 103.11%) for AUCinf, and 98.54% (94.70 - 102.54%) for Cmax. CONCLUSION: Since the 90% CI for Cmax, AUClast and AUC(0-infinity) ratios were all within the 80 - 125% interval proposed by the US Food and Drug Administration, we concluded that the citalopram formulation elaborated by Eurofarma Laboratórios Ltda. was bioequivalent to the cipramil formulation in its rate and extent of absorption.

Administration, Oral↗

PubMed2004

Effects of different protocol doses of low power gallium-aluminum-arsenate (Ga-Al-As) laser radiation (650 nm) on carrageenan induced rat paw ooedema.

The purpose of the present study was to investigate the effect of the low power laser therapy on the acute inflammatory process. Male Wistar rats were used. The rat paw oedema was induced by sub-plantar injection of carrageenan, the paw volume was measured before and 1, 2, 3 and 4 h after the injection using a hydroplethysmometer. To investigate the mechanism action of the Ga-Al-As laser on inflammatory oedema, parallel studies were performed using adrenallectomized rats or rats treated with sodium diclofenac. Different laser irradiation protocols were employed for specific energy densities (EDs), exposure times and repetition rates. The rats were irradiated with the Ga-Al-As laser during 80 s each hour. The ED that produced an anti-inflammatory effect were 1 and 2.5 J/cm(2), reducing the oedema by 27% (P<0.05) and 45.4% (P<0.01), respectively. The ED of 2.5 J/cm(2) produced anti-inflammatory effects similar to those produced by the cyclooxigenase inhibitor sodium diclofenac at a dose of 1 mg/kg. In adrenalectomized animals, the laser irradiation failed to inhibit the oedema. Our results suggest that low power laser irradiation possibly exerts its anti-inflammatory effects by stimulating the release of adrenal corticosteroid hormones.

Adrenalectomy↗

PubMed2004

Implications of the use of semicarbazide as a metabolic target of nitrofurazone contamination in coated products.

Data from the Brazilian Agricultural Ministry show that before the implementation of the Brazilian programme of nitrofuran control in February 2003, the cases of contamination of Brazilian chicken by nitrofurans were almost exclusively due to furaltadone. After May 2003, such cases decreased until no more reports of Brazilian chicken contamination with this nitrofuran were reported. Curiously, after April 2003, an increase was observed in the numbers of contaminated samples by semicarbazide, the target metabolite of nitrofurazone. Most Brazilian chicken found to be contaminated with semicarbazide has been covered with flour, salt and spices. For this reason, the authors' laboratory initialized a programme for tracing possible sources of food contamination by semicarbazide. After several semicarbazide positives in flour of controlled origin (results varying between 2.2 and 5.2 microg kg(-1)), the different additives used in the cereal industry as flour improvement agents were studied. The results indicate that the compound azodicarbonamide was responsible for the source of the contaminant semicarbazide.

Animals↗

PubMed2004

Effects of amphetamine on immune-mediated lung inflammatory response in rats.

OBJECTIVE: The present study analyzed the effects of acute amphetamine (AMPH) treatment on immune-mediated lung inflammatory response in rats. METHODS: There were four experiments. In the first and second experiments, rats were treated with AMPH (1 mg/kg) or 0.9% NaCl, and locomotor activity (experiment 1) and serum AMPH concentrations (experiment 2) were measured 1 or 12 h after treatment. In the third experiment, rats which were immunized with ovalbumin (OVA) were treated 14 days later with 0.9% NaCl or AMPH (1 mg/kg). Twelve hours after these treatments, all animals were submitted to challenge by 1% OVA inhalation being analyzed afterwards for bronchoalveolar lavage fluid (BAL), peripheral blood and bone marrow cellularity. In the fourth and final experiment, rats were treated and studied as for experiment 3, except that half of the animals within each group were previously treated with metyrapone prior to the OVA challenge. RESULTS: In the non-immunized rats, AMPH treatment induced an increase in locomotor activity synchronized to high serum AMPH concentrations 1 h after, but not 12 h after treatment. In OVA-challenged rats, AMPH treatment decreased the total number of inflammatory cells, recovered in both BAL and peripheral blood and increased the total number of bone marrow cells. These effects, observed 1 day after OVA challenge, were abrogated by previous metyrapone treatment. CONCLUSION: AMPH treatment changed HPA-axis responsiveness to the stress condition imposed by the OVA challenge decreasing lung and blood leukocytes cellularity most probably via corticosterone actions on bone marrow activity.

Amphetamine↗

PubMed2004

Cyclosporine bioequivalence study: quantification using fluorescence polarization immunoassay (FPIA) and radioimmunoassay (RIA).

OBJECTIVE: The aim of study was to compare the bioavailability of 2 cyclosporine capsule formulations (100 mg; Sigmasporin Microoral from Novaquímica Divisão Nature's Plus Farmacêutica Ltd., Brazil, as test formulation and Sandimmune Neoral from Novartis Biociências S.A., Brazil, as reference formulation) in 24 healthy male volunteers. METHODS: The study was open, randomized, with a 2-period crossover, a 1-week washout interval between doses. Blood samples were obtained over a 12-hour interval after each oral administration of cyclosporine (2 capsules of 100 mg of each formulation). Cyclosporine blood concentrations were quantified using a fluorescence polarization immunoassay (FPIA) method provided by Abbott Axsym System and Cyclo-Trac SP. Whole-blood radioimmuoassay (RIA) kit was provided by DiaSorin. These assays provided concentration-time curves for cyclosporine in blood concentration from which the following pharmacokinetic parameters were obtained: AUC(last), AUC(inf), Cmax. RESULTS: Geometric mean and 90% confidence intervals (CI) of Microoral/Neoral as percent ratios were 94.5% (90.8-98.4%) for AUC(last), 93.8% (89.7-98.1%) for AUC(inf), and 98.1% (94.5-101.8%) for Cmax when cyclosporine was determined using FPIA and 96.1% (91.9 to 100.6%) for AUC(last), 95.2% (90.2-100.5%) for AUC(inf), and 99.4% (96.4-102.4%) for Cmax using RIA. CONCLUSION: Since the 90% CI for Cmax, AUC(last) and AUC(inf) ratio were within the 80-125% interval proposed by US-FDA, it is concluded that Sigmasporin Microoral 100 mg capsule formulation is bioequivalent to Sandimmune Neoral 100 mg capsule formulation with regard to both rate and the extent of absorption.

Administration, Oral↗

PubMed2004

Phentolamine bioequivalence study.

OBJECTIVE: To assess the bioequivalence of 2 tablet formulations of phentolamine (Regitine phentolamine 40 mg tablet formulation by Novartis, Brazil, as test formulation, and Vasomax, phentolamine 40 mg tablet formulation by Schering Plough S.A., Brazil, as reference formulation). METHODS: A single 40 mg oral dose of each formulation was administered to 36 male healthy volunteers. The study was conducted after screening, using an open, randomized, 2-period crossover design, a 7-day interval between doses, and wash-out period of at least 4 weeks. Plasma samples for determination of phentolamine were obtained predose and at intervals over 720 min postdose. Plasma concentrations were quantified by reversed-phase liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reactions monitoring (MRM) method. Precision of the method was evaluated using calibration curves and plasma quality control samples. The subjects were monitored throughout the study. Systolic and diastolic blood pressure and pulse rate measurement were taken predose and at intervals up to 720 min. Tolerance of both products was good. No serious adverse reactions were reported. The pharmacokinetic parameters calculated for both compounds included: AUC(0-720 min), AUC(0-infinity), C(max), Ca and k(e). RESULTS: The maximum concentrations reached (C(max)) were compared. Regitine 40 mg formulation C(max) geometric mean ratio was 108.29% (90% CI = 98.58-118.96) of Vasomax 40 mg formulation. The areas under the curve (AUC(0-720 min)) were compared. Regitine 40 formulation (AUC(0-720 min)) geometric mean ratio was 102.33% (90% CI = 97.21-107.72) of Vasomax 40 mg formulation. CONCLUSION: Since the 90% CI for both C(max) and AUC ratio where inside the 80 to 125% interval proposed by the Food and Drug Administration, it is concluded that Regitine 40 mg tablet is bioequivalent to Vasomax for the rate and extent of absorption.

Administration, Oral↗

PubMed2001

Role of nitric oxide on in vitro human eosinophil migration.

Eosinophils purified from the rat peritoneal cavity have been found to contain nitric oxide synthase (NOS) functionally coupled to a cyclic GMP transduction pathway that is involved in in vitro eosinophil migration, but no studies on cell locomotion have been done with purified human eosinophils. Therefore, this study was carried out to investigate the effects of N(omega) -nitro-L-arginine methyl ester (L-NAME; a non-selective NOS inhibitor), 1-(2-trifluoromethylphenyl) imidazole (TRIM; a type I/type II NOS inhibitor), 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT; a selective type II NOS inhibitor), and 1H-[1,2,4]-oxidiazolo[4,3-a] quinoxalin-1-one (ODQ; a soluble guanylate cyclase inhibitor) on human eosinophil migration induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP). Human eosinophils were purified from peripheral blood of healthy volunteers using a Percoll gradient followed by an immunomagnetic cell separator. Chemotaxis was evaluated using a 48-well microchemotaxis chamber. The fMLP (1.0 x 10(-7) M)-induced eosinophil migration was reduced significantly by l-NAME (0.1 and 1.0 mM), whereas the inactive enantiomer N(omega)-nitro-D-arginine methyl ester (D-NAME) had no effect. The inhibition by l-NAME was restored by sodium nitroprusside (0.25 mM). The NOS inhibitors AMT and TRIM (0.05 to 0.25 mM each) also markedly attenuated fMLP-induced chemotaxis. Additionally, ODQ (0.01 to 0.5 mM) concentration-dependently inhibited fMLP-induced migration, and the inhibition was restored by 2.0 mM dibutyryl cyclic GMP. In conclusion, this study demonstrates that human eosinophils present a nitric oxide-cyclic GMP pathway that is involved in the in vitro locomotion of this cell type.

Cell Movement↗

PubMed2001

Comparative effect of Phoneutria nigriventer spider venom and capsaicin on the rat paw oedema.

Capsaicin, the pungent component of hot peppers, and the venom of the spider Phoneutria nigriventer are able to activate sensory nerves resulting in cutaneous neurogenic plasma extravasation. This study was undertaken to compare the ability of these substances to evoke oedema in the rat hind-paw and mechanisms underlying this effect. Subplantar injection of either Phoneutria nigriventer venom (PNV; 1-100 microg/paw) or capsaicin (10-200 microg/paw) caused a significant paw oedema that was potentiated by CGRP (10 pmol/paw). In rats treated neonatally with capsaicin to deplete neuropeptides, the paw oedema induced by either PNV (100 microg/paw) or capsaicin (100 microg/paw) was partially reduced (P<0.05). The tachykinin NK1 receptor antagonist SR140333 (0.2 micromol/kg; i.v.) prevented the paw oedema induced by the tachykinin NK1 receptor agonist GR73632 (30 pmol/paw) and partially reduced paw oedema induced by PNV or capsaicin. Treatment of rats with compound 48/80 (5 mg/kg; s.c. 3 days) or with both H1 receptor antagonist (mepyramine; 1 nmol/paw) and 5-HT receptor antagonist (methysergide; 1 nmol/paw) significantly inhibited PNV- or capsaicin-induced paw oedema. The combined treatment with mepyramine and methysergide and SR140333 further reduced PNV- and capsaicin-induced paw oedema. The bradykinin B2 receptor antagonist Hoe 140 affected neither PNV- nor capsaicin-induced responses. Our results suggest that PNV and capsaicin each induce paw oedema that is partially mediated by activation of sensory fibers culminating in the release of substance P as well as by activation of mast cells which in turn release amines such as histamine and 5-HT.

Animals↗

PubMed2001

Expression of neuronal isoform of nitric oxide synthase in spinal neurons of neonatal rats after sciatic nerve transection.

Motoneuron death induced by sciatic nerve transection in neonatal rats has been related to induction of the neuronal isoform of nitric oxide synthase (nNOS), a diaphorase of which one of the cofactors is nicotinamide adenine dinucleotide phosphate (NADPH). We transected the sciatic nerve of neonatal rats (P2) and examined nNOS expression by immunostaining in neurons of the sciatic pool and of other spinal levels on the 5th day after surgery. No correspondence was observed between the surviving motoneurons and nNOS positive cells. The appearance and distribution of nNOS positive neurons at all spinal levels and laminae were similar to those of adult animals. These results are at variance with previous studies which showed correlation between motoneuron loss after axotomy and number of NADPH-diaphorase positive motoneurons after sciatic transection.

Animals↗

PubMed2001

Contribution of C-fibers to leucocyte recruitment in bronchoalveolar lavage fluid and pleural cavity in the rat.

The effect of neonatal capsaicin (8 methyl-N-vanillyl-6-nonenamide) treatment on the leucocyte infiltration into the airways and pleural cavity was investigated in rats actively sensitized with ovalbumin. The animals were neonatally injected with either capsaicin (50 mg/kg, s.c., 2nd day of life) or vehicle (10% ethanol and 10% Tween 80). At adult ages, the animals were actively sensitized with ovalbumin (200 microg, s.c.) and 14 days later they were intratracheally (or intrapleurally) challenged with ovalbumin. The substance P level in bronchoalveolar lavage fluid of the capsaicin group was reduced by >90% compared to control group (vehicle), confirming the efficacy of capsaicin treatment. In the capsaicin group, the number of neutrophils (but not of eosinophils and mononuclear cells) in bronchoalveolar lavage fluid of sensitized animals was significantly higher than the control group. Intrapleural injection of ovalbumin in sensitized rats caused a significant neutrophil influx at 6 h that was markedly increased in the capsaicin-pretreated animals compared to control group. The counts of eosinophils and mononuclear cells in the pleural exudates did not differ significantly between capsaicin and control groups. The increased levels of immunoglobulin (Ig)E, IgG1 and IgG2a anti-ovalbumin antibodies in serum of sensitized rats did not differ between capsaicin and control groups. In conclusion, the exacerbated pulmonary neutrophil recruitment caused by the capsaicin neonatal treatment is unrelated to increase in serum immunoglobulin antibodies, and suggests a protective role for C-fibers in attenuating the allergic neutrophil infiltration.

Animals↗

PubMed2001

Role of nitric oxide on the increased vascular permeability and neutrophil accumulation induced by staphylococcal enterotoxin B into the mouse paw.

The role of nitric oxide (NO) on the increase in vascular permeability and neutrophil migration induced by staphylococcal enterotoxin B (SEB; 25 microgram/paw) in the mouse was investigated in this study. The NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) [but not its inactive enantiomer N(omega)-nitro-D-arginine methyl ester (D-NAME)], given intravenously (25-100 micromol/kg) or subplantarly (0.25-1.0 micromol/paw), reduced SEB-induced paw oedema significantly. A similar response was observed with aminoguanidine, given either intravenously (200-600 micromol/kg) or subplantarly (2 micromol/paw). In contrast to paw oedema, the plasma exudation in response to SEB was not affected by the subplantar injection of L-NAME or aminoguanidine. The inhibition of oedema and plasma exudation by systemic treatment with L-NAME or aminoguanidine was reversed by co-injection of the vasodilator iloprost (0.3 nmol/paw). Subplantar injection of SEB (25 microgram/paw) increased by 69% the myeloperoxidase (MPO) activity of SEB-treated paws, indicating the presence of neutrophils. Intravenous (12.5-50 micromol/kg) or subplantar (0.125-0.5 micromol/paw) administration of L-NAME (but not of its inactive enantiomer, D-NAME) largely reduced the MPO activity in SEB-treated paws. Similarly, intravenous (200-600 micromol/kg) or subplantar (2 micromol/paw) administration of aminoguanidine significantly reduced the MPO values of the SEB-injected paws. The vasodilator iloprost (0.3 nmol/paw) completely reversed the inhibition by L-NAME or aminoguanidine of the MPO activity in SEB-injected paws. Our results show that the increased vascular permeability and neutrophil accumulation in response to subplantar injection of SEB in the mouse are inhibited by L-NAME and aminoguanidine by mechanisms probably involving reduction of local microvascular blood flow.

Animals↗

PubMed2001

Amlodipine bioequivalence study: quantification by liquid chromatography coupled to tandem mass spectrometry.

OBJECTIVE: To assess the bioequivalence of two amlodipine tablet formulations (Amlodipine 5 mg tablet from Merck S.A. Indústrias Químicas, Brazil as test formulation and Norvasc 5 mg tablet from Laboratórios Pfizer Ltd., Brazil as reference formulation) in 24 healthy volunteers of both sexes. METHODS: The study was conducted using an open, randomized two-period crossover design with a 4-week washout interval. Plasma samples were obtained over a 144 h period. Plasma amlodipine concentrations were analyzed by combined liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reaction monitoring (MRM). From the amlodipine plasma concentration vs time curves, the following pharmacokinetic parameters were obtained: AUC(last), AUC(0-inf) and C(max). The statistical interval proposed was 80-125% according to the US Food and Drug Administration Agency. RESULTS: The limit of quantification was 0.1 ng/ml for plasma amlodipine analysis. The geometric mean and the 90% confidence interval (CI) test/reference ratios were 101.2 (92.9-110.2%) for AUC(last), 99.6 (91.5-108.4%) for AUC(0-inf) and 98.5 (89.0-109.1%) for C(max). CONCLUSION: Since the 90% CI for AUC(last), AUC(0-inf) and C(max) ratios were within in the 80-125% interval proposed by the US FDA, it was concluded that Amlodipine 5 mg tablet (test formulation) was bioequivalent to Norvasc 5 mg tablet, in terms of both rate and extent of absorption.

Adolescent↗

PubMed2001

Quantification of nimesulide in human plasma by high-performance liquid chromatography/tandem mass spectrometry. Application to bioequivalence studies.

A method based on liquid chromatography with negative ion electrospray ionization and tandem mass spectrometry is described for the determination of nimesulide in human plasma. Liquid-liquid extraction using a mixture of diethyl ether and dichloromethane was employed and celecoxib was used as an internal standard. The chromatographic run time was 4.5 min and the weighted (1/x) calibration curve was linear in the range 10.0-2000 ng x ml(-1). The limit of quantification was 10 ng x ml(-1), the intra-batch precision was 6.3, 2.1 and 2.1% and the intra-batch accuracy was 3.2, 0.3 and 0.1% for 30, 300 and 1200 ng x ml(-1) respectively. The inter-batch precision was 2.3, 2.8 and 2.7% and the accuracy was 3.3, 0.3 and 0.1% for 30, 300 and 1200 ng x ml(-1) respectively. This method was employed in a bioequivalence study of one nimesulide drop formulation (nimesulide 50 mg x ml(-1) drop, Medley S/A Indústria Farmacêutica, Brazil) against one standard nimesulide drop formulation (Nisulid, 50 mg x ml(-1) drop, Astra Médica, Brazil). Twenty-four healthy volunteers (both sexes) took part in the study and received a single oral dose of nimesulide (100 mg, equivalent to 2 ml of either formulation) in an open, randomized, two-period crossover way, with a 2-week washout interval between periods. The 90% confidence interval (CI) for geometric mean ratios between nimesulide and Nisulid were 93.1-109.6% for C(max), 87.7-99.8% for AUC(last) and 88.1-99.7% for AUC(0-infinity). Since the 90% CI for the above-mentioned parameters were included in the 80-125% interval proposed by the US Food and Drug Administration, the two formulations were considered bioequivalent in terms of both rate and extent of absorption.

Adolescent↗