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R Fanelli

Publications and source records attributed to R Fanelli.

At least 73 records · Page 4Linked to original sources
PubMed1993

Left atrial thrombus and spontaneous echo-contrast in nonanticoagulated mitral stenosis. A transesophageal echocardiographic study.

OBJECTIVE: The aim of the study was to investigate if evidence at transthoracic echocardiography (TTE) of left atrial (LA) thrombus and LA spontaneous echo-contrast (LA SEC), which are potential precursors of embolization, can be predicted by clinical and TTE variables in nonanticoagulated mitral valve stenosis (MS). DESIGN: Clinical (age, NYHA class, rhythm, previous embolization) and TTE variables were related to transesophageal echocardiography (TEE) evidence of LA thrombus and/or LA SEC. SETTING: Nonanticoagulated MS was the setting. PATIENTS: Fifty-nine patients had MS, and they were not receiving anticoagulant or antiplatelet therapy (24 in sinus rhythm and 35 in atrial fibrillation). Previous arterial embolization had occurred in 12 patients (20.3 percent). MEASUREMENTS: The following TTE variables were analyzed: mitral orifice area (pressure half-time method), mitral gradient (Bernouilli's equation), LA end-systolic area, and mitral regurgitation (color Doppler grading). LA thrombus and LA SEC were analyzed by monoplane TEE. RESULTS: LA thrombus was found by TEE in 12 patients (20.3 percent). Of these 12, 11 (91.6 percent) were in atrial fibrillation. LA SEC was found by TTE in 2 patients (3.5 percent) and by TEE in 40 (67.8 percent) (p < 0.001). Previous embolization had occurred only in patients with LA SEC, of whom 5 had and 7 did not have LA thrombus. Patients with LA SEC, compared with those without LA SEC, were characterized by more frequent advanced NYHA class, atrial fibrillation, smaller mitral valve area, and larger LA size. By multivariate regression analysis, atrial fibrillation and LA end-systolic area were factors related to both LA thrombus and LA SEC, whereas mitral area was related only to LA SEC. However, whereas LA SEC was accurately predicted by the presence of atrial fibrillation (sensitivity: 87.5 percent; specificity: 100 percent) and a LA area > or = 30 cm2 (sensitivity: 72.5 percent; specificity: 89.5 percent), among patients with LA SEC no clinical or TTE variable accurately identified those with actual LA thrombus. CONCLUSIONS: TEE is not necessary in many patients with MS in order to recognize LA SEC. However, when actual LA thrombus detection is necessary for clinical decision making, TEE should be performed.

Adult↗
PubMed1993

Rapid, direct enzyme immunoassay of 11-keto-thromboxane B2 in urine, validated by immunoaffinity/gas chromatography-mass spectrometry.

We have developed a direct enzyme immunoassay (EIA) for quantifying immunoreactive 11-keto-thromboxane B2 (iKTXB) in unprocessed human urine. Cross-reactivity with other thromboxane metabolites and prostanoids was negligible. Analytical recovery of 11-keto-TXB2 in urine specimens was 97.4% to 99.8%. Total imprecision for two clinical specimens was 8.5% and 12.2%. Intake of acetylsalicylic acid decreased the measured concentration of iKTXB. Cardiopulmonary bypass, a procedure known to activate platelets, increased the mean excretion rate of iKTXB 10-fold. Simultaneous gas chromatography-mass spectrometry analysis of 11-keto-TXB2 and 11-keto-2,3-dinor TXB2 in urine specimens (n = 17) from healthy subjects indicated that urinary iKTXB concentrations measured by EIA represented a sum of the two 11-keto metabolites. We conclude that the direct EIA is sufficiently sensitive, rapid, simple, and specific to allow screening for alterations in thromboxane biosynthesis in patients.

Aspirin↗
PubMed1992

Urinary excretion of O6-butylguanine after the administration of N-nitroso-N-butylurea in rats.

O6-Butylguanine was detected in the urine of rats given the butylating agent N-nitroso-N-butylurea. O6-Butylguanine contents in the 24-h rat urine samples after i.p. doses of 50, 100, and 200 mg/kg N-nitroso-N-butylurea were 1.03 +/- 0.41 (SE), 8.30 +/- 1.70, and 59.53 +/- 6.52 pmol, respectively. This suggests that O6-butylguanine formation in nucleic acids might be repaired in vivo, possibly by base excision, besides other mechanisms. After i.v. doses of 0.1 and 1 mg/kg of O6-butylguanine to rats urinary excretion did not exceed 2% of the administered dose, suggesting that the amount of O6-butylguanine effectively released by base excision might be much larger than that detected in the urine after N-nitroso-N-butylurea. Inhibition of the enzyme O6-alkyl-DNA transferase by N-nitrosodimethylamine increased urinary O6-butylguanine resulting from exposure to N-nitroso-N-butylurea (100 mg/kg i.p.) up to four times, thus confirming an alternative DNA repair mechanism.

Animals↗
PubMed1992

In vitro metabolism of bladder carcinogenic nitrosamines by rat liver and urothelial cells.

In order to establish the importance of the target organ in the activation of bladder carcinogens, we compared rat liver and urothelial cell alpha-hydroxylation activities using as substrates N-nitrosobutyl(4-hydroxybutyl)amine and its metabolite N-nitrosobutyl(3-carboxypropyl)amine, two potent urinary bladder carcinogens in animals. Previous studies have shown that the production of molecular nitrogen can serve as an indicator of nitrosamine alpha-hydroxylation. The use of doubly 15N-labelled nitrosamines and the gas chromatography-mass spectrometric detection of 15N2 formed gives a measurement of the extent of this metabolic step. Various amounts of 15N-labelled substrates were incubated for 60 min at 37 degrees C with rat liver S9 preparations or urothelial cell homogenates in the presence of a NADPH generating system. Both enzyme sources metabolized 15N-labelled N-nitrosobutyl(4-hydroxybutyl)amine and N-nitrosobutyl(3-carboxypropyl)amine through the alpha-hydroxylation pathway. Using hepatic S9 fractions, 15N2 production from 15N-labelled N-nitrosobutyl(4-hydroxybutyl)amine increased from 1.69 +/- 0.02 nmol/h per mg protein (mean +/- S.E.) to 5.78 +/- 0.5 with substrate concentrations ranging between 0.55 and 5.55 mM. 15N2 produced by urothelial cell homogenates was about 40-50% that of the liver S9. 15N-labelled N-nitrosobutyl(3-carboxypropyl)amine was also metabolized through the alpha-hydroxylation pathway both by hepatic S9 and urothelial cell homogenates, though to a lesser extent. 15N2 production was about 10-times less than from 15N-labelled N-nitrosobutyl(4-hydroxybutyl)amine, but again urothelial cell 15N2 production was about 40-50% that of the liver. Treatment with phenobarbital resulted in a 2.7-fold increase in the 15N2 produced from 15N-labelled N-nitrosobutyl(4-hydroxybutyl)amine by hepatic S9. No effect was observed with urothelial cell homogenates. Acetone treatment had no effect on 15N2 production from 15N-labelled N-nitrosobutyl(4-hydroxybutyl)amine by hepatic S9, but raised 15N2 production by urothelial cell homogenates 1.8 times. Although the liver has a greater capacity than the bladder for activating the 15N-labelled nitrosamines studied, the target organ can metabolize bladder carcinogens, thus increasing the possibility of a local toxic effect. Moreover, the distribution of P-450 isozymes might be different in the bladder and this could affect the metabolism of nitrosamines reportedly formed in the human bladder in some pathological conditions.

Acetone↗
PubMed1992

Urinary excretion of thromboxane and prostacyclin metabolites during chronic low-dose aspirin: evidence for an extrarenal origin of urinary thromboxane B2 and 6-keto-prostaglandin F1 alpha in healthy subjects.

In vivo biosynthesis of thromboxane and prostacyclin is currently evaluated by measuring urinary excretion of selected metabolites. Urinary thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) (non-enzymatic hydrolysis products of thromboxane and prostacyclin) are thought to derive from renal biosynthesis of the parent compounds, while enzymatic metabolites such as 2,3-dinor-TXB2 and 2,3-dinor-6-keto-PGF1 alpha appear to be mainly derived from systemic (platelet) thromboxane and (vascular) prostacyclin, respectively. Using immunoaffinity extraction and high-resolution gas chromatography-negative ion chemical ionization mass spectrometry (HRGC-NICIMS), we measured the paired excretion of non-enzymatic and enzymatic metabolites of thromboxane and prostacyclin in healthy subjects before, during and after an eight-day schedule of oral low-dose aspirin (30 mg/day), a treatment known to inhibit platelet and perhaps vascular but not renal cyclooxygenase. Low-dose aspirin cumulatively reduced urinary excretion of TXB2 and 2,3-dinor-TXB2 (about 80% inhibition on day 8 of aspirin treatment, P less than 0.01), as well as 6-keto-PGF1 alpha and 2,3-dinor-6-keto-PGF1 alpha (about 45% inhibition on day 8 of aspirin treatment, P less than 0.01). Excretion of all metabolites recovered slowly after aspirin withdrawal. Urinary PGE2, taken as an index of renal cyclooxygenase activity, was not inhibited by aspirin. A highly significant correlation was found between paired excretion values of non-enzymatic vs. enzymatic metabolites of thromboxane and prostacyclin in all individuals studied (TXB2 vs. 2,3-dinor-TXB2 (r = 0.91 +/- 0.03); 6-keto-PGF1 alpha vs. 2,3-dinor-6-keto-PGF1 alpha (r = 0.92 +/- 0.06], irrespective of aspirin treatment. TXB2/2,3-dinor-TXB2 and 6-keto-PGF1 alpha/2,3-dinor-6-keto-PGF1 alpha mean ratios remained unchanged throughout the experiment. These data do not support the view that urinary TXB2 and 6-keto-PGF1 alpha derive mainly from renal biosynthesis in healthy subjects, but rather suggest that they may represent a fraction of systemic (platelet) thromboxane and (vascular) prostacyclin escaping metabolism. These data also suggest that chronic low-dose aspirin may partly inhibit vascular prostacyclin in addition to platelet thromboxane biosynthesis.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

DNA damage induced by alachlor after in vitro activation by rat hepatocytes.

We investigated the ability of alachlor to cause DNA damage by measuring single-strand breaks (SSB) in DNA, after metabolic activation by freshly isolated rat hepatocytes. Incubation of different concentrations of alachlor with rat hepatocytes led to numerous metabolites. The majority, isolated and identified by GC-MS analysis, were products arising from reactions catalyzed by the P-450 monooxygenase system, arylamidase and flavin mixed-function oxidase/cytochrome P-450 monooxygenase. The results, using freshly isolated rat hepatocytes, showed that in these conditions several potentially DNA damaging metabolites were produced; this experimental condition was used to assess DNA damage induced by the mixture of alachlor and its metabolites. The alkaline elution technique showed that at 200 microM and more clearly at 400 microM there were some small fragments that eluted in the first fraction. This fragmentation was probably due to alachlor cytotoxicity. In addition to the small DNA fragments eluting in the first fraction there were other larger DNA fragments. These DNA-SSB were most evident at the alachlor concentration of 400 microM, but also at 200 microM and 100 microM, whereas at 10 microM the DNA elution rate appeared comparable to that of controls. The results suggest that some unstable and DNA-reactive metabolites might interact with DNA causing SSB and such interaction might be important in relation to the mechanism of alachlor-induced DNA damage. However, it may not be possible to clarify whether SSB are the result of direct DNA interaction of the compound or of secondary cellular processes after chemical treatment.

Acetamides↗
PubMed1991

Determination of 19-nortestosterone, testosterone and trenbolone by gas chromatography-negative-ion mass spectrometry after formation of the pentafluorobenzylcarboxymethoxime-trimethylsilyl derivatives.

The known reaction of 3-ketosteroids with carboxymethoxylamine (to form the corresponding carboxymethoximes), followed by esterification of the carboxyl group with pentafluorobenzyl bromide, has been used to obtain derivatives of 19-nortestosterone, testosterone and trenbolone suitable for high-sensitivity detection with gas chromatography-negative-ion chemical ionization mass spectrometry. These derivatives, after further silylation of the alcoholic groups of the steroids, showed excellent chromatographic and spectrometric characteristics and were detectable in the low picogram range. The derivatization gave rise to the formation of two isomers which were distinguishable by gas chromatography. The existence of the two isomers was also confirmed by high-performance liquid chromatography. Examples of the usefulness of this derivatization procedure are given for the analysis of 19-nortestosterone, testosterone and trenbolone in meat and urine samples. By the use of immunoaffinity extraction and addition of deuterated internal standards (synthesized by isotopic exchange), the new derivatization procedure allowed a correct identification and quantitation of the steroids and reached very low detection limits [0.02 ppb (10(9] for 19-nortestosterone and testosterone, 0.06 ppb for trenbolone].

Animals↗
PubMed1991

Determination of zeranol and beta-zearalanol in calf urine by immunoaffinity extraction and gas chromatography-mass spectrometry after repeated administration of zeranol.

A method for the determination of zeranol and its metabolite beta-zearalanol in bovine urine is described. It has been applied to samples from calves given multiple subcutaneous doses of zeranol. Samples were extracted with immunoaffinity columns containing antibodies raised against zeranol and were analysed by gas chromatography-mass spectrometry. The immunoaffinity columns were prepared by coupling immunoglobulin G fractions obtained from rabbit antisera with a Sepharose matrix. The immunizing agent was carboxybutylzeranol coupled to bovine serum albumin. Gas chromatography-mass spectrometry was performed in the negative-ion chemical ionization mode, after derivatization of the compounds to their pentafluorobenzyl ethers, and allowed detection of analytes with a sensitivity of 0.01 ppb in spiked urine. The derivatization method and the gas chromatographic determination were also applied to the similar compounds zearalanone, zearalenone and beta-zearalenol. A synthesis of dideuterated zeranol and beta-zearalanol by isotopic exchange is described. These deuterated analogues had an isotopic purity of more than 99% and were used for quantitation of zeranol and beta-zearalanol by isotope dilution mass spectrometry. The recoveries of zeranol and beta-zearalanol, using the immunoaffinity columns, were determined after extraction from spiked urine and were 84 and 64%, respectively. The urines of treated calves were collected for several days after treatments and were analysed after hydrolysis with beta-glucuronidase and arylsulphatase. The samples showed variable but generally decreasing concentrations of zeranol and beta-zearalanol. The levels of beta-zearalanol ranged from less than 0.01 to 98 ppb and were 1.2-3.2 times higher than those of zeranol.

Animals↗
PubMed1991

Migration of vinyl chloride into PVC-bottled drinking-water assessed by gas chromatography-mass spectrometry.

The migration of vinyl chloride (VC) into drinking-water bottled in polyvinyl chloride (PVC) was studied in relation to storage time, using a gas chromatographic-mass spectrometric method. Trideuterated vinyl chloride was used as internal standard. VC concentrations in the water rose progressively in direct (linear) relation to the time after bottling (about 1 ng/litre/day). The time of storage of PVC-packaged foodstuffs may affect the daily oral intake of this monomer, which in some cases may exceed 100 ng/person/day.

Drinking↗
PubMed1991

Systolic ejection murmurs in the elderly: aortic valve and carotid arteries echo-Doppler findings.

UNLABELLED: Two-dimensional echographic and color Doppler studies of the heart and carotid arteries (CA) were performed in 45 patients greater than sixty-five years old without aortic stenosis, 23 with (Group 1) and 22 without (group 2) precordial ejection systolic murmur (SM). Aortic cusps thickening was found in 11 Group 1 (48%) and 2 Group 2 (9%) patients (p less than 0.001). Aortic root and aortic arch size were similar in the two groups. Maximum aortic flow velocity was significantly greater in Group 1 (200 60 cm/sec) than in Group 2 (120 20 cm/sec) (p less than 0.001). Left ventricular outflow systolic maximum velocity was similar in the two groups. A bilateral neck murmur was heard in 10/23 Group 1 patients (43%); in this group, patients with cervical SM had a greater maximum aortic flow velocity than those without cervical SM (230 + 60 cm/sec vs 172 + 32 cm/sec, p less than 0.001). In Group 1, 3 patients had a cervical SM louder on one neck side; only in these 3 patients were ipsilateral obstructive CA plaques found. A unilateral neck SM was heard in 4/22 Group 2 patients (18%); in these 4, ipsilateral obstructive CA were found. CONCLUSIONS: (1) in the elderly, precordial ejection SM is related to mild increase in maximum aortic flow velocity and thickening of aortic cusps; (2) in patients with precordial SM radiated to both neck sides, maximum aortic flow velocity tends to be more markedly increased; (3) in patients with precordial SM, a cervical SM louder on one neck side should suggest coexistent ipsilateral CA stenosis.

Aged↗
PubMed1991

N-Nitrosobutyl(4-hydroxybutyl)amine alpha-hydroxylation by rat liver and urothelial cell homogenates.

Determination of molecular nitrogen formed as a consequence of nitrosamine alpha-hydroxylation provides a useful means for studying the extent of activation of these compounds in target and nontarget organs and tissues. alpha-Hydroxylation in rat liver and urothelial cells was compared using as substrate doubly 15N-labelled N-nitrosobutyl(4-hydroxybutyl)amine (15N-NBHBA), a potent bladder carcinogen in rodents. Both enzyme sources metabolized 15N-NBHBA through the alpha-hydroxylation pathway. 15N2 production was dependent on the amount of substrate incubated. Vmax values for 15N2 production by urothelial cells and by liver postmitochondrial supernatant were 4.47 and 3.21 nmol/mg protein per h, respectively.

Animals↗
PubMed1990

Determination of O6-butylguanine in DNA by immunoaffinity extraction/gas chromatography-mass spectrometry.

A sensitive, specific, and rapid method for quantitating the minor adduct O6-butylguanine (O6BuG) in hydrolyzed DNA has been developed by combining immunoaffinity chromatography and high resolution gas chromatography-negative ion chemical ionization-mass spectrometry. Polyclonal antibodies raised against O6BuG were coupled to CNBr-activated Sepharose 4B and used for sample clean-up and extraction of the specific O6-alkylguanine. After addition of O6BuG and its deuterium labeled analogue (O6BuG-D7), used as internal standard, hydrolyzed DNA was applied on the immunoaffinity column and washed with water, and the immunoadsorbed butylated guanines were eluted with acetone/water cetome/water (95/5) before gas chromatographic derivatization. O6BuG and O6BuG-D7 were analyzed and quantitated by high resolution gas chromatography-negative ion chemical ionization-mass spectrometry as their pentafluorobenzyl-trimethylsilyl derivatives. Immunoaffinity column capacity and O6BuG recovery from this column were 1.53 nmol O6BuG/column and 62 +/- 5%, respectively. The method was applied to evaluate O6BuG levels in DNA butylated in vitro with 10 mM N-nitroso-Nr-butylurea or isolated from rats given an i.p. dose of 185 mg/kg N-nitroso-N-butylurea or N-nitrosodibutylamine. In the first case the level of modifications present in calf thymus DNA was 104 mumol O6BuG/mol guanine, and in the second case O6BuG in liver DNA was about 6 times higher after N-nitroso-N-butylurea (2.11 mumol O6BuG/mol guanine) than after N-nitrosodibutylamine (0.34 mumol O6BuG/mol guanine) treatment. These results indicate that O6BuG formed in vivo can be isolated and quantitated by this method, which may also be useful for studying DNA damage and repair mechanisms.

Animals↗
PubMed1990

Analysis of diethylstilbestrol, dienestrol and hexestrol in biological samples by immunoaffinity extraction and gas chromatography-negative-ion chemical ionization mass spectrometry.

A method has been developed for the detection of diethylstilbestrol, together with dienestrol and hexestrol, using extraction with a single immunoaffinity column containing antibodies raised against diethylstilbestrol, followed by gas chromatography-negative-ion chemical ionization mass spectrometry. Immunoaffinity columns were prepared by coupling immunoglobulin G fractions obtained from rabbit antisera with a Sepharose matrix. The immunizing agent was synthesized by introducing a carboxyl group into the diethylstilbestrol molecule and coupling this product to bovine serum albumin. The columns were used for immunoadsorption of diethylstilbestrol and other estrogens, after dilution of samples with phosphate buffer, and were eluted with acetone-water (95:5 v/v). A derivatization method suitable for gas chromatographic-mass spectrometric analysis of diethylstilbestrol and other estrogens was developed using pentafluorobenzyl bromide and ethanolic potassium hydroxide as reagents. The derivatives obtained were detectable at the sub-picogram level using gas chromatography with negative-ion chemical ionization mass spectrometry. Recoveries of cis- and trans-diethylstilbestrol, dienestrol and hexestrol from the immunoaffinity columns, determined after extraction from urine, plasma and buffer, ranged from 28 to 96%. The sensitivity for diethylstilbestrol in urine samples was ca. 10 ppt. The method was applied to the analysis of urine from calves given a single dose of 10 mg of diethylstilbestrol. Free and glucuronic acid conjugated diethylstilbestrol decreased with time, but their ratio was variable.

Animals↗