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Biomedical subjects

R Pastorelli

Publications and source records attributed to R Pastorelli.

32 records · Page 2Linked to original sources
PubMed1989

Orally dissolved ketanserin in acute treatment of hypertensive patients: a controlled study.

The effectiveness of 40 mg ketanserin dissolved in the mouth in reducing blood pressure was studied in 17 hypertensive patients. Comparison with a placebo group has shown that in the first 10 min the blood pressure trend was similar for both groups; a significant fall was recorded 20 and 60 min after administration for systolic blood pressure and after 60 min for diastolic blood pressure. Therefore, orally dissolved ketanserin decreases blood pressure more rapidly than with standard oral consumption, and may be used when a rapid progressive decrease in blood pressure is required. This antihypertensive effect might be more rapid by administering more soluble tablets or ketanserin in solution.

Administration, Oral↗
PubMed1988

Effect of acute and chronic butylated hydroxyanisole administration on in vivo glucuronidation of N-nitrosobutyl(4-hydroxybutyl)amine in rats.

The urinary metabolic pattern of N-nitrosobutyl(4-hydroxybutyl)amine (NB4HBA) administered ip at a dose of 5 mg/kg body weight was studied in animals either pretreated with butylated hydroxyanisole (BHA) as a single oral dose of 50 or 250 mg/kg, or fed a diet containing 0.1 or 0.5% BHA. The 24-hr urinary excretion of NB4HBA, its glucuronic acid-conjugate (NB4HBA-G) and N-nitrosobutyl(3-carboxypropyl)amine (NB3CPA) in control rats were 0.12, 0.75 and 30% of the administered dose, respectively, and were not changed after a single oral dose of 50 mg BHA/kg. NB4HBA-G was significantly reduced in the urine of rats given 250 mg BHA/kg. In vitro assays carried out using rat-hepatic microsomal preparations as the source of the enzyme UDP-glucuronyl transferases (GT) and NB4HBA as the substrate, suggest that a competition between NB4HBA and BHA for the same enzyme may be the cause of the decreased NB4HBA-G excretion observed in vivo. A fourfold increase in NB4HBA-G urinary excretion was observed after chronic 0.5% BHA feeding; moreover, the glucuronic acid-conjugate of NB3CPA (NB3CPA-G), which was not detected in the controls or after acute BHA treatment, appeared in the urine of rats given dietary BHA for 3 wk, accounting for about 10% of the administered NB4HBA. In vitro experiments indicate that the increased glucuronides excretion may be the result of an elevated hepatic GT activity.

Animals↗
PubMed1988

Effect of butylated hydroxyanisole added in vitro or administered to rats on N,N-dibutylnitrosamine and N-butyl-N-(4-hydroxybutyl)nitrosamine metabolism by post-mitochondrial supernatant of liver homogenates.

The effect of butylated hydroxyanisole (BHA) on P-450-dependent omega-hydroxylation of N,N-dibutylnitrosamine (NDBA) to N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), and the further oxidation of BBN to N-butyl-N-(3-carboxypropyl)nitrosamine (BCPN) by the alcohol/aldehyde dehydrogenase system was investigated using the post-mitochondrial supernatant of liver homogenates (S9) from acutely and chronically BHA pretreated animals or S9 fractions from untreated rats with BHA added. Acute oral BHA (50 and 250 mg.kg-1) did not change NDBA omega-oxidation, which was reduced by 35% only when the compound was administered 0.5% in the diet for 3 weeks. BCPN formation from BBN was unaffected by acute and chronic BHA pretreatment. In order to verify whether BHA or its metabolite(s) had a direct effect on NDBA and BBN oxidation, the compound was added to S9 fractions from untreated rats at various concentrations. Only when BHA concentrations were equimolar or in a 10-fold molar excess to the substrate concentration, we observed 30-50% inhibition of BBN formation and a reduced BCPN formation (60-80% of control values), from BBN. Thus, only at very high BHA concentrations could we confirm the inhibition of P-450-dependent mixed function oxidase and alcohol dehydrogenase activities involved in the metabolism of NDBA and BBN.

Administration, Oral↗
PubMed1988

Acute captopril treatment in elderly hypertensive patients: a controlled study.

We studied the effectiveness of 50 mg captopril in reducing blood pressure in 27 elderly hypertensive patients. Comparison with a placebo group has shown a significant difference 20 and 60 min after administration (dissolved in the mouth). A significant decrease in blood pressure was found at each observation time (10, 20 and 60 min) in the captopril-treated group, whereas in the placebo group there was no significant fall after the first 10 min. Therefore, captopril dissolved in the mouth decreases blood pressure more rapidly than with standard oral consumption, and can be considered a first-choice drug when a rapid decrease in blood pressure is desired.

Administration, Oral↗
PubMed1988

[Isoflurane pollution in operating rooms].

In three operating rooms of a Sardinian hospital, the Authors have measured the air levels of isoflurane using static samplers. Anaesthetic mean daily concentrations ranged from 3.5 to 41.5 ppm in room A, from 4.1 to 24.4 ppm in room B, from 9.5 to 30.4 ppm in room C above all depending on the length and the number of surgical operations. The Authors emphasize the need of suitable prevention measures.

Air Pollutants, Occupational↗
PubMed1987

Effect of butylated hydroxyanisole on in vitro and in vivo nitrosation of dibutylamine.

The effect of the food additive butylated hydroxyanisole on the nitrosation of dibutylamine was studied in vitro and in vivo, in rats. At the highest concentration tested, butylated hydroxyanisole significantly inhibited the in vitro formation of N-nitrosodi-n-butylamine from dibutylamine and nitrite by 35%. This effect was not observed in animals given dibutylamine, NaNO2 and butylated hydroxyanisole by gavage in the same ratio that produced an effect in vitro. The oral administration of butylated hydroxyanisole to rats given 0.5% nitrate in the drinking water and dibutylamine (0.38 mmol/kg 3 times/day p.o.) was also with no effect, although the experimental model used proved suitable for studying the modulating effect on endogenous nitrosation of different chemicals such as ascorbic acid or potassium thiocyanate. The discrepancy between in vitro and in vivo results is discussed.

Animals↗
PubMed1987

Effect of butylated hydroxyanisole on the metabolism of N-nitrosodi-n-butylamine and N-nitrosobutyl(4-hydroxybutyl)amine by rat hepatic S9 preparations in vitro.

N-Nitrosodi-n-butylamine (NDBA), the NADPH generating system and various concentrations of butylated hydroxyanisole (BHA) added to rat hepatic S9 fractions resulted in a significant drop (30-50%) in N-nitrosobutyl(4-hydroxybutyl)amine (NBHBA) formation and a consequent rise in the amount of substrate recovered unchanged. When NBHBA and NAD+ were incubated with BHA and S9 fractions, the amount of N-nitrosobutyl(3-carboxypropyl)amine (NBCPA) was decreased by 20-40%, and the amount of unmetabolized NBHBA increased.

Animals↗
PubMed1984

Kinetics of 3-tert-butyl-4-hydroxyanisole (BHA) in man.

High-resolution capillary gas chromatography-mass spectrometry with selective ion monitoring and using deuterated 3-tert-butyl-4-hydroxyanisole (BHA) as an internal standard was used to measure BHA in the plasma and urine of human volunteers after oral administration of 30 or 5 mg of the compound in olive oil. Pharmacokinetic studies showed similar plasma-concentration profiles in subjects treated with either level of BHA. About 20% of the administered dose was excreted as BHA glucuronide in the urine within the first 24 hr.

Administration, Oral↗
PubMedDate not supplied

Benzo[a]pyrene diol epoxide adduct formation in mouse and human hemoglobin: physicochemical basis for dosimetry.

The interactions of human hemoglobin (hHb) with the anti-diol epoxide of benzo[a]pyrene (aBaPDE) and with the corresponding tetrols formed by hydrolysis of the epoxide were investigated with the aim of characterizing the covalent adducts formed by reaction of the epoxide with the protein. The major product (80% of the total) was determined to be an ester resulting from oxirane ring opening by one or several (unidentified) carboxylate group(s). Minor products were characterized as adducts formed by reaction with amino or heterocyclic nitrogen by comparison of their UV spectra with those of model compounds. There was no evidence for reaction with cysteine. Formation of ester adducts by aBaPDE with mouse hemoglobin (mHb) following administration of BaP to mice was also investigated. It was found that esters constituted the majority of the adducts formed by aBaPDE and a substantial fraction of the total adducts formed. The esters formed by mHb were significantly less stable than those formed by hHb, both in vivo and in vitro. The instability of mHb ester adducts is believed by the responsible for differences among previous descriptions of the in vivo binding of BaP to mHb.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMedDate not supplied

Fluoranthene metabolism: human and rat liver microsomes display different stereoselective formation of the trans-2,3-dihydrodiol.

The metabolism of the environmental carcinogen fluoroanthene by human liver microsomes was compared to that by liver microsomes from rats treated with Aroclor 1254. Although the human-derived system gave primarily one product, similar metabolites were noted from each system. Enantiomers of the major metabolic product, in both cases the trans-2,3-dihydrodiol, were separated by chiral stationary-phase chromatography. Absolute configurations were assigned by application of the benzoate exciton chirality rules to the CD spectra of the 4-(dimethylamino)benzoyl esters. Liver microsomes from Aroclor 1254-treated rats produced the R,R enantiomer of the diol in 75-78% enantiomeric excess, while human liver microsomes produced this enantiomer in only 6-12% excess. The activities of these enantiomers were compared in Salmonella typhimurium strain TM677 mutagenicity assays employing the 9000g supernatant of Aroclor 1254-induced rat liver homogenates. Both the syn- and anti-2,3-dihydrodiol 1,10b-epoxides, which had only been inferred to be metabolites in previous studies, were isolated from the microsomal incubations by preparative reverse-phase HPLC. The evident exceptional aqueous stabilities of these diol epoxides were further examined by half-life determination experiments. Their tetrahydrotetrol hydrolysis products were also noted in the metabolite HPLC profiles. The structures of the tetrahydrotetrols were confirmed by total synthesis.

Animals↗
PubMedDate not supplied

Immunomodulatory effects of occupational exposure to mancozeb.

The effects of occupational exposure to ethylene-bis-dithiocarbamate of manganese and zinc on the immune system were evaluated in a group of mancozeb-exposed manufacturers and controls. The immune system tests revealed the following: (a) lymphocyte proliferative responses triggered by different activators and mitogen-induced IL-2 production were higher in exposed subjects than in controls; (b) production of monocyte/macrophage-derived IL-1 and polyclonal IgG and IgM, by beta-lymphocytes, did not differ between exposed subjects and controls; (c) percentages and absolute numbers of total T-cells, T-helper cells, T-suppressor/cytotoxic cells, activated T-cells, total beta-cells, and natural killer cells were similar in exposed subjects and controls; (d) serum immunoglobulin classes and complement fractions were within the range of normality; and (e) rheumatoid factor and non-organ-specific serum autoantibodies were absent in exposed and control subjects. An increase in T-cell functional response was found in the exposed group, suggesting a slight immunomodulator effect of mancozeb in conditions of low-level, prolonged occupational exposure.

Air Pollutants, Occupational↗