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Biomedical subjects

R Fanelli

Publications and source records attributed to R Fanelli.

At least 91 records · Page 5Linked to original sources
PubMed1990

Anti-inflammatory pharmacology and mechanism of the orally active capsaicin analogs, NE-19550 and NE-28345.

We have evaluated the properties of a new class of anti-inflammatory agents derived from capsaicin, using the analogs NE-19550 (N-vanillyloleamide) and NE-28345 (N-oleyl-homovanillamide) as examples. This class displayed an atypical profile in the assays utilized, including 1) anti-edema and antileukocyte migration activity in the rat carrageenan pleurisy assay without suppression of pleural prostanoid synthesis, 2) blockade of human platelet aggregation induced by arachidonate or PAF but not that induced by the PGH2 analog U-46619, without equivalent inhibition in vitro of mammalian cyclooxygenase or thromboxane synthetase preparations, 3) greater potency and efficacy in the rat implanted sponge assay than in the adjuvant arthritis assay, without inhibition of LTB4 or 15-HETE synthesis in vitro, 4) stronger topical activity in the mouse croton oil inflamed ear assay than the guinea pig UV erythema assay, and 5) oral activity in the rat carrageenan paw edema assay and mouse phenylquinone abdominal constriction rest combined with failure to induce gastric erosion in rats at therapeutic doses. We conclude that NE-19550 and NE-28345 do not act like conventional NSAIDs via suppression of arachidonic acid metabolism.

Animals↗
PubMed1990

Alpha-oxidative metabolism of the bladder carcinogens N-nitrosobutyl(4-hydroxybutyl)amine and N-nitrosobutyl(3-carboxypropyl)amine within the rat isolated bladder.

The most widely accepted metabolic pathway leading to the formation of reactive intermediates from nitrosamines involves enzymatic hydroxylation at the carbon atom alpha to the nitroso moiety. All subsequent steps are non-enzymatic reactions and the final result is the stoichiometric formation of a cationic product and molecular nitrogen. Thus the amount of molecular nitrogen evolved can be used as an indicator of alpha-hydroxylation. The use of doubly 15N-labelled nitrosamines and the detection of 15N2 by MS makes it simpler to measure the extent of alpha-hydroxylation. We have studied the alpha-oxidation of doubly 15N-labelled N-nitrosobutyl(4-hydroxybutyl)amine (BBN) and its metabolite N-nitrosobutyl(3-carboxypropyl)amine (BCPN), two potent urinary bladder carcinogens in animals, within the target organ. Various amounts of 15N-labelled BBN ranging from 0.1 to 5 mumol were incubated at 37 degrees C for 4 h in the isolated rat bladder and the formation of 15N2 was measured by GC-MS. 15N2 production was linear up to 1 mumol and represented approximately 0.1% of the substrate incubated. Time-course experiments showed that 15N2 production was linear over a 6 h incubation period, ranging from 2.16 +/- 0.05 to 4.55 +/- 0.33 nmol/mg urothelial cell protein. 15N-labelled BCPN (1-5 mumol) was also incubated within the rat isolated bladder. 15N2 production from BCPN was approximately 10 times less than that from BBN. The results indicate that, though to a lower extent, the target organ activates 15N-labelled BBN and BCPN through the alpha-hydroxylation pathway.

Animals↗
PubMed1990

[Forme fruste of Gorlin's syndrome with a left ventricular neoplasm].

We report on a 25-year-old man, referred for atypical chest pain and negative T waves in leads V5-V6. A cardiac tumor, localized in the posterolateral left ventricular wall was diagnosed in this patient by nuclear techniques and bidimensional echocardiography. A complex form of pluridistrectual dysmorphic disorder (hypertelorism, prognathism, frontal bossing, multiple cysts of the mandible, calcification in falx cerebri, etc) was also present, suggesting a limited form of Gorlin's syndrome (nevoid basal cell carcinoma syndrome).

Adult↗
PubMed1990

[Diagnosis of recent posterolateral myocardial infarction: an electrocardiographic, echocardiographic and scintigraphic study].

ECG and 2D echocardiography were studied in 64 patients with previous myocardial infarction and evidence of posterolateral fixed defect at 201 TI scintigraphy. The defect was isolated posterolateral in 47 patients (group 1), and posterolateral + inferoapical in 17 (group 2). Thirty subjects with no history of myocardial infarction and no 201 TI defects constituted the control group. We calculated sensitivity, specificity and predictive value of ECG and 2D echocardiography (pertinent wall motion abnormality) in the recognition of posterolateral infarction. ECG data were also analyzed using multivariate analysis. Among the ECG criteria, a positive T wave in V1 proved to be 100% sensitive and 76% specific both in group 1 and in group 2. At multivariate analysis, a 2-variable model (positive T wave inV1 + R/S ratio greater than or equal to 1 in V1-V2) had a sensitivity of 95 and 100% in group 1 and 2, respectively; the specificity was 80%. A 3-variable model (+ R wave duration in V1-V2 greater than or equal to 0.04 sec) proved to be less sensitive (70 and 88% in group 1 and 2, respectively), with a specificity of 97%. A pertinent dyssynergy at 2D echocardiography was 70% sensitive for posterolateral myocardial infarction in group 1, but only 29% in group 2, with a specificity of 100%. These results indicate: 1) standard ECG is more sensitive but less specific than 2D echocardiography in the recognition of previous postolateral myocardial infarction; 2) the recognition of posterolateral involvement can be frequently missed by 2D echocardiography in patients with associated inferior myocardial infarction.

Adult↗
PubMed1990

[Increase of plasma levels of beta-endorphin during maximum bicycle ergometry effort in sedentary and trained subjects].

Plasmatic levels of beta-endorphin during maximal graded bicycle stress test were measured by RIA on extracted plasma in 10 well-trained (A group) and in 8 untrained subjects (C group). Blood samples were obtained at rest, at peak work load and at the third, 10th and 90th min of recovery. For every stress test the following were evaluated: exercise time, maximum work load, total work load, maximum double product and mean K (an index of velocity of heart rate recovery during the first three minutes after the exercise). Both groups A and C showed a significant rise in beta-endorphin activity at the third minute of recovery; the increase was significantly greater in trained rather than in sedentary subjects (p less than 0.01). Beta-endorphin release was closely related to mean K; no relationship was found between exercise time, maximum work load, total work load, maximum double product and beta-endorphin rise. Our data shows that a release of beta-endorphin occurs during the initial phase of recovery after a maximal stress test; beta-endorphin rise is greater in trained subjects and correlates with the speed of heart rate recovery, but has no relationship with the duration and the grade of the effort. Whether beta-endorphin increase plays a role in the rapid decrease of adrenergic tone which occurs after exercise or represents a secondary phenomenon remains to be determined.

Adult↗
PubMed1989

Metabolism of thromboxane B2 in the isolated perfused rat kidney: mass spectrometric identification of urinary products.

The metabolism of thromboxane B2 (TXB2), the stable breakdown product of thromboxane A2, has been studied in isolated perfused kidney preparations using a recirculating system. In a first experiment, TXB2 was infused at a rate of 20 micrograms/kg per min. In a second experiment, a 1:1 mixture of TXB2 and octadeuterated TXB2 (0.4 microgram/kg per min each) was infused. Urinary samples collected during the infusion of TXB2 or vehicle were extracted on C18 cartridges and derivatized to methyl or pentafluorobenzyl ester, methyloxime, trimethylsilyl ether. Samples were analyzed by high-resolution gas chromatography-mass spectrometry in the electron impact and negative ion chemical ionization modes. Products of beta-oxidation, reduction of the delta 5,6 double bond and dehydrogenation at C-11 (2,3-dinor-TXB2, 2,3-dinor-TXB1, 2,3,4,5-tetranor-TXB1 and 11-dehydro-TXB2) were identified in addition to unmetabolized TXB2. 2,3,4,5-tetranor-TXB1 and 2,3-dinor-TXB1 were the most abundant metabolites.

Animals↗
PubMed1989

Quantitative profiling of 6-ketoprostaglandin F1 alpha, 2,3-dinor-6-ketoprostaglandin F1 alpha, thromboxane B2 and 2,3-dinor-thromboxane B2 in human and rat urine by immunoaffinity extraction with gas chromatography-mass spectrometry.

A rapid and simple method based on immunoaffinity extraction, stable isotope dilution and gas chromatography-mass spectrometry has been developed for profiling urinary metabolites of prostacyclin and thromboxane. 6-Ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), 2,3-dinor-6-ketoprostaglandin F1 alpha (2,3-dinor-6-keto-PGF1 alpha), thromboxane B2 (TXB2) and 2,3-dinor-thromboxane B2 (2,3-dinor-TXB2) were quantitatively extracted from human or rat urine spiked with deuterated internal standards using mixed-bed columns containing immobilized anti-6-keto-PGF1 alpha and anti-TXB2 antibodies (cross-reacting with 2,3-dinor-6-keto-PGF1 alpha and 2,3-dinor-TXB2, respectively). The extract was directly derivatized to form pentafluorobenzyl ester, methyloxime, trimethylsilyl ether derivatives. Quantitation was performed by stable isotope dilution assay and high-resolution gas chromatography-negative ion chemical ionization mass spectrometry, by monitoring the carboxylate anions (M-181) of the derivatized metabolites. The method was applied to evaluate the urinary excretion of 6-keto PGF1 alpha, 2,3-dinor-6-keto-PGF1 alpha, TXB2 and 2,3-dinor-TXB2 in humans and rats. Results were in accordance with previously reported data obtained by other methods. Novel data on the urinary excretion of 2,3-dinor-6-keto-PGF1 alpha in rats under basal conditions are presented. This sensitive and selective method represents a significant advance in terms of rapidity and simplicity over other immunoaffinity-gas chromatography-mass spectrometry methods for measuring single prostanoids, such as 6-keto-PGF1 alpha or TXB2, since it allows profiling of a group of metabolites whose balance is important in several physiopathological conditions.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Effect of low-dose aspirin on fetal and maternal generation of thromboxane by platelets in women at risk for pregnancy-induced hypertension.

There is evidence that aspirin in low doses favorably influences the course of pregnancy-induced hypertension, but the mechanism, although assumed to involve suppression of the production of thromboxane by platelets, has not been established. We performed a randomized study of the effect of the long-term daily administration of 60 mg of aspirin (n = 17) or placebo (n = 16) on platelet thromboxane A2 and vascular prostacyclin in women at risk for pregnancy-induced hypertension. Low doses of aspirin were associated with a longer pregnancy and increased weight of newborns. Serum levels of thromboxane B2, a stable product of thromboxane A2, were almost completely (greater than 90 percent) inhibited by low doses of aspirin. The urinary excretion of immunoreactive thromboxane B2 was significantly reduced without changes in the level of 6-keto-prostaglandin F1 alpha, a product of prostacyclin. Mass spectrometric analysis showed that aspirin reduced the excretion of the 2,3-dinor-thromboxane B2 metabolite--mainly of platelet origin--by 81 percent and of thromboxane B2, probably chiefly of renal origin, by 59 percent. The urinary excretion of 6-keto-prostaglandin F1 alpha and of its metabolite 2,3-dinor-6-keto-prostaglandin F1 alpha was not affected. Low doses of aspirin only partially (63 percent) reduced neonatal serum thromboxane B2. No hemorrhagic complications were observed in the newborns. Thus, in women at risk for pregnancy-induced hypertension, low doses of aspirin selectively suppressed maternal platelet thromboxane B2 while sparing vascular prostacyclin, but only partially suppressed neonatal platelet thromboxane B2, allowing hemostatic competence in the fetus and newborn.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Prostaglandin and thromboxane synthesis by human intracranial tumors.

Prostaglandin (PG) and thromboxane (TX) production by homogenates of human intracranial tumors (33 gliomas, 32 meningiomas, six brain metastases) and "normal" brain (n = 26) from tumor-bearing patients was studied. PGF2 alpha, PGE2, PGD2, 6-keto-PGF1 alpha (the hydrolysis product of PGI2) and TXB2 (the hydrolysis product of TXA2) were determined by high-resolution gas chromatography-mass spectrometry after ex vivo metabolism of endogenous arachidonic acid. Prostanoid profiles (relative abundance of each metabolite) were different for gliomas and meningiomas, but similar for gliomas and their nontumoral counterpart, i.e., "normal" brain. Mean overall prostanoid production was significantly higher in gliomas (539 +/- 95) and meningiomas (523 +/- 69) than in "normal" brain (198 +/- 23). Prostanoid synthesis significantly increased with anaplastic grade (glioblastomas greater than anaplastic astrocytomas greater than slow-growing astrocytomas greater than "normal" brain), while profiles did not substantially change (TXB2 was the most and 6-keto-PGF1 alpha the least abundant product). Meningioma profiles showed no marked prevalence of any particular metabolite and no major differences between histological subgroups. All brain metastases from different carcinomas (n = 5) showed a prevalence of TXB2 and PGE2 and very low PGD2 synthesis.

Arachidonic Acid↗
PubMed1989

Antiinflammatory action of salicylates: aspirin is not a prodrug for salicylate against rat carrageenin pleurisy.

A current hypothesis postulates that the antiinflammatory effect of aspirin (acetylsalicylic acid) is mediated by its metabolite salicylic acid through inhibition of PGE2 synthesis. We tested this hypothesis in rats with carrageenin-induced pleurisy. Aspirin or salicylate, given orally, reduced exudation and cell migration into the pleural cavity, aspirin being more potent than salicylate. The antiinflammatory effect of aspirin cannot be explained only in terms of salicylate formation. Doses of aspirin and salicylate that inhibit inflammation by 50% result in salicylate levels in the exudate of 70 +/- 12 and 323 +/- 17 micrograms/ml, respectively. At a significant antiinflammatory dose (100 mg/kg), salicylate did not reduce the prostaglandin and thromboxane content of the exudate. This indicates that inhibition of cyclooxygenase is not a likely mechanism for the antiinflammatory effect of salicylate. Salicylate only reduced the amount of 6-keto-PGF1 alpha in the exudate at higher doses (200 mg/kg), while aspirin at an equally antiinflammatory dose (50 mg/kg) reduced the content of 6-keto-PGF1 alpha, TXB2, PGD2 but not of PGE2 in the exudate. It therefore seems unlikely that an inhibition of PGE2 synthesis is the common mechanism by which aspirin and salicylate exert their antiinflammatory effects. These results do not supported the hypothesis that aspirin is a prodrug for salicylate but rather indicate that both compounds may exert their antiinflammatory effects partly by different mechanisms.

Animals↗
PubMed1989

Molecular species analysis of phospholipids by negative ion fast atom bombardment mass spectrometry: application of surface precipitation technique.

Eight phospholipidic classes from bovine brain cortex and soybean were prepared and purified by preparative high-performance and liquid chromatography, and their molecular species were identified by negative ion fast atom bombardment mass spectrometry using the 'surface precipitation' method. Its main advantages are: (i) clear-cut and abundant diagnostic ions for structural elucidation of the species; (ii) fragments characteristic of the main fatty acids, the polar head-group and the molecule frame in phospholipids; (iii) less background caused by the liquid matrix.

Animals↗
PubMed1989

A gas chromatographic mass spectrometric assay for the determination of aphidicolin in plasma of cancer patients.

A gas chromatographic-mass spectrometric (GC-MS) method is described for the determination of the novel anticancer agent aphidicolin in plasma. The extraction was carried out in a solvent mixture of hexane:isopropanol (10:1) and the external standard aphidicolane was added after evaporation of the organic phase. The residue was then redissolved in a derivatizing mixture containing bis(trimethylsilyl)trifluoracetamide as sililating agent, pyridine, and trimethylchlorosilane, and allowed to react at 80 degrees C for 2 h. After GC separation of the derivatized samples, selected ion recording analysis was done, monitoring the ions at mass 523.3 and 448.3 for aphidicolin and aphidicolane, respectively. The mean recovery +/- SD of aphidicolin from plasma was 73.5 +/- 11.6% in the range from 5 to 800 ng. This method was applied to determine aphidicolin plasma levels in three cancer patients in Phase I clinical trials of aphidicolin-17-glycinate administered as a 1-h iv infusion. Two patients received dose of 290 mg/m2 and the third received 435 mg/m2. Aphidicolin plasma levels at the end of infusion were very low, and the drug rapidly disappeared from plasma with a terminal (beta) half-life of 2 h.

Adult↗
PubMed1989

Renal metabolism and urinary excretion of thromboxane B2 in the rat.

We wanted to evaluate whether the kidney tissue can metabolize thromboxane (Tx) B2 and, specifically, whether the 2,3-dinor metabolite might be formed in the kidney and excreted in the urine. For this purpose, we used an isolated perfused kidney preparation exposed to vehicle or TxB2 at different infusion rates. Approximately 96% of the total TxB2 infused was recovered in the venous effluent, whereas approximately 1% was found in urine. Isolated perfused kidneys exposed to [3H]TxB2 eliminated in the urine 1.2% of the [3H]TxB2 infused, measured by thin-layer chromatographic analysis, and actively metabolized [3H]TxB2 to 2,3-dinor-TxB2, 11-dehydro-TxB2, and possibly 2,3,4,5-tetranor-TxB1. No metabolites of TxB2 were recovered in the venous effluent. As a marker of renal TxB2 metabolic activity, urinary 2,3-dinor-TxB2 was quantified by high-resolution gas chromatography-negative-ion chemical ionization mass spectrometry. The 2,3-dinor-TxB2 was detected both before and during TxB2 infusion in urinary samples but not in the venous effluent. The ratio of 2,3-dinor-TxB2-TxB2 increased during the infusion reaching a peak value immediately after stopping the TxB2 infusion. These results indicate that, in the rat, the kidney tissue metabolizes TxB2 to 2,3-dinor-TxB2, and both TxB2 and 2,3-dinor-TxB2 are excreted in the urine.

Animals↗
PubMed1989

A fast atom bombardment-mass spectrometric method to quantitate lysophosphatidylserine in rat brain.

A method to quantitate lysophosphatidylserine by fast atom bombardment-mass spectrometry using 1-hexa-decanoyl-sn-glycero-3-phospho-L-serine as internal standard is described. The standard curve is linear with a correlation coefficient r2 = 0.999 from 10 to 1000 ng. This curve has been used to quantitate LPS in rat brain using phosphorus assay as a test control. We found 475 +/- 70 ng of LPS in 1 mg of tissue (n = 3). This method presents advantages due to its sensitivity and its capability to give molecular information of the unmodified compound.

Animals↗
PubMed1988

Pharmacokinetic profile and metabolism of N-nitrosobutyl-(4-hydroxybutyl)amine in rats.

N-Nitrosodibutylamine and its omega-hydroxylated metabolite N-nitrosobutyl(4-hydroxybutyl)amine (NB4HBA) induce tumors in the urine bladder of different animal species through their common urinary metabolite N-nitrosobutyl(3-carboxypropyl)amine (NB3CPA), resulting from the oxidation of the alcoholic group of NB4HBA to a carboxylic group. NB4HBA disappearance from blood, the formation of its main metabolites, NB3CPA and NB4HBA-glucuronide (NB4HBA-G), and their urinary excretion, were investigated in rats after an i.v. dose of 1 mg/kg (5.7 mumol/kg). NB3CPA and NB4HBA-G formation was readily detectable 2 min after treatment and levels were still measurable at 120 and 30 min, respectively. The parent compound disappeared from blood 90 min after injection. The NB4HBA blood concentration-time profile was adequately described by a one-compartmental linear model. NB4HBA half-life was 8 min, total body clearance and renal clearance were 86.1 and 0.22 ml/min/kg, respectively. The 0-96-h urinary excretion of NB4HBA was 0.3% of the administered dose. NB3CPA half-life was 15 min; NB3CPA and NB4HBA-G urinary excretion were 36 and 11.7%, respectively, urinary excretion of known compounds accounting for less than 50%. After i.v. injection of NB3CPA equimolar to the NB4HBA dose, only 50% of unchanged compound was recovered in the urine and after NB4HBA-G, 41% of the administered dose was excreted unchanged, NB3CPA accounting for 10%. Thus NB3CPA and NB4HBA-G might undergo further biotransformation, suggesting that NB3CPA may not be the ultimate carcinogen responsible for urinary bladder tumor induction.

Animals↗
PubMed1988

Identification of metabolites of tiropramide in human urine.

The metabolites of tiropramide were extracted from the urine of healthy volunteers given tiropramide hydrochloride orally. Eight metabolites of tiropramide were found by gas chromatography/mass spectrometry. Three were identified on the basis of their mass spectra, retention times and comparison with synthetic standards. For the others a probable structure is proposed on the basis of their mass spectra.

Adult↗