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Biomedical subjects

A Fazio

Publications and source records attributed to A Fazio.

At least 73 records · Page 4Linked to original sources
PubMed1984

A sensitive gas chromatographic assay for the determination of serum viloxazine concentration using a nitrogen-phosphorus-selective detector.

A gas-liquid chromatographic procedure for measuring the serum levels of the antidepressant viloxazine is described. The drug and the internal standard [imipramine (IMI)] are extracted from 1 ml serum. The method involves a three-step extraction, derivatization of viloxazine with acetic anhydride, and injection into a gas chromatograph equipped with a nitrogen-phosphorus-selective detector. The retention times for IMI and viloxazine were 4.7 and 6.1 min, respectively. The standard curves were linear over the 100- to 2,000-ng/ml range. The recovery averaged 64.5% and the lowest detection limit was 80 ng/ml. The within-run and day-to-day coefficients of variations were 11.9 and 12.5%, respectively, at 250 ng/ml, and 8.9 and 9.2%, respectively, at 1,500 ng/ml. The method is adequate both for single-dose pharmacokinetic studies and for monitoring serum viloxazine levels in chronically treated patients.

Adult↗
PubMed1984

Effect of viloxazine on serum carbamazepine levels in epileptic patients.

The present study describes the interaction between carbamazepine (CBZ) and viloxazine, a recently synthesized antidepressant agent. Seven epileptic patients on chronic anticonvulsant therapy showed a significant (p less than 0.005) increase in steady-state serum CBZ levels (from 8.1 +/- 2.5 SD to 12.1 +/- 2.5 SD micrograms/ml) when viloxazine (300 mg/day) was added to the therapy. The effect was associated with the appearance of mild CBZ intoxication. The symptoms of this intoxication (i.e., dizziness, ataxia, fatigue, drowsiness) disappeared rapidly, and serum CBZ levels decreased to the basal values, when viloxazine administration was stopped.

Adult↗
PubMed1984

Valproic acid-ethosuximide interaction: a pharmacokinetic study.

The present pharmacokinetic study was designed to investigate the possible interaction between valproic acid (VPA) and ethosuximide (ESM) in humans. Six drug-free healthy volunteers, four men and two women, 18-42 years of age, received a single oral dose of 500 mg ESM before and during a treatment with VPA at 800- to 1,600-mg daily doses. The second ESM dose was given 9 days after VPA administration was started. In this latter condition, a significant (p less than 0.05) increase in ESM serum half-life, from 44 to 54 h on average, and a significant (p less than 0.05) decrease in total body clearance, from 11.2 to 9.5 ml/min on average, were observed. Other pharmacokinetic parameters were unchanged and showed values similar to those reported in the literature. Serum VPA levels ranged between 66.8 and 95 micrograms/ml. Two subjects showed no evidence of interaction. Although a great interindividual variability in the occurrence of VPA-ESM interaction can be observed, the present study indicates that VPA is able to inhibit the metabolism of ESM. Possible factors affecting this interaction are hypothesized and discussed.

Adolescent↗
PubMed1983

Intra-daily oscillations in dipropylacetic acid plasma levels with two or three daily doses of dipropylacetamide in epileptic patients.

The diurnal fluctuations in dipropylacetic acid (DPA) plasma levels were examined in ten epileptic patients following a chronic treatment with 3 or 2 daily doses of dipropylacetamide (DPM). The highest/lowest DPA levels ratios observed throughout 24 hrs were 1.18 and 1.36, respectively, but the difference in the data was not statistically significant (p greater than 0.05). The present results indicate that a reduction of the frequency of the daily administrations of the drug can be made with consequent possible improvement in the patient's compliance. The clinical value of the oscillations in DPA serum levels is also revised in the light of the data reported in the literature.

Adolescent↗
PubMed1982

Increased dipropylacetic acid bioavailability from dipropylacetamide by food.

The present study was designed to investigate the influence of food on dipropylacetic acid (DPA) absorption from dipropylacetamide (DPM). Six healthy male volunteers received at weekly intervals, in a crossover randomized fashion, a single oral dose of 60 mg DPM, as 2 X 300-mg capsules, in a fasting state and after a standard meal. In the latter state, the lag time of DPA appearance in the serum increased significantly (p less than 0.02) from 0.6 +/- 0.2 to 2.3 +/- 1.2 h (mean values +/- SD). Maximal DPA serum levels and bioavailability increased significantly (p less than 0.05), with mean values of 27.7 +/- 19.8 and 19.0 +/- 14.7%, respectively, following food. The slower gastric emptying with a consequent improved DPM exposure to metabolizing enzymes and changes in gastric pH probably accounted for these findings. These results suggest that it is more advantageous to take DPM after meals. This helps to reduce gastrointestinal disturbances and to promote DPA absorption.

Absorption↗
PubMed1981

Dipropylacetic acid plasma levels; diurnal fluctuations during chronic treatment with dipropylacetamide.

Diurnal variation in dipropylacetic acid (DPA) plasma levels was investigated in 47 and 42 epileptic patients, chronically treated with sodium dipropylacetate and dipropylacetamide (DPM), respectively, taken alone or in addition to other antiepilepic drugs. Fluctuation in DPA plasma levels was significantly less in patients receiving dipropylacetamide. The slow absorption and the more prolonged plasma half-life of dipropylacetamide accounted for these findings. Although the importance of diurnal fluctuations in DPA levels has not yet been established, possible clinical implications are discussed.

Adolescent↗
PubMed1980

Preliminary data on dipropylacetamide absorption in rats.

Absorption of dipropylacetamide, after oral and i.m. administration, was studied in different groups of male albino Wistar rats. After i.m. administration, only unmodified amide was found in plasma, whereas oral administration of the drug was followed by the presence of dipropylacetic acid and dipropylacetamide in plasma. This last compound resulted in a higher amount in a further group of rats previously treated with neomycin in order to avoid the action of intestinal flora. Present results seem to exclude an hepatic role in the transformation of dipropylacetamide in dipropylacetic acid.

Absorption↗
PubMed1975

[Comparison between the way of intravenous administration of flagellin from Salmonella typhosa to the margial vein in the ear and into the mesenteric superior vein. Preliminary note].

Rabbits receiving three injections of PFA intravenously in ear, after that first treatment gave a weak antibody response, after the second one a rapid and copious increase of agglutination titre; the third injection induced a very small increase. In rabbits injected with PFA in superior mesenteric vein the first injection produced a little effect, the second induced a little effect too; the third injection performed in auricular vein, gave a substancial rapid and copious antibody response. This behaviour is similar to that obtained after the second injection in the first set of experiments. The PFA injected two times in mesenteric vein caused certainly a massive phagocytosis of antigen by Kupffer cells. Nevertheless this copious phagocytosis can exercise only an action of "priming", not a response of secondary type. For this purpose it is necessary an injection in the ear vein to provoke a direct intervention of lymphonodal reticular phagocytes. The phenomenon can be related to the proteic nature of the antigen.

Agglutination↗
PubMedDate not supplied

Standardization of 65Zn by 4piPC-gamma coincidence counting method with efficiency extrapolation.

A 65Zn solution was standardized by the 4piPC-gamma efficiency-extrapolation coincidence counting method. Theoretical aspects of coincidence equations, efficiency equations and linearity conditions are reviewed. Experimental measurements were performed for two low level discrimination thresholds for the PC channel (counting K+L or K X-rays or Auger electrons from EC decay) and for three different settings of the gamma window. Requirements on gamma channel set-up for linear extrapolation were established by using a Pb absorber or by proper gamma window setting. The measured activity values were discussed and found in good agreement with those obtained with a calibrated ionization chamber.

Algorithms↗
PubMedDate not supplied

A preliminary intercomparison of gamma-ray spectrometry on building materials.

A preliminary intercomparison on gamma-ray spectrometry determination of natural radionuclides in building materials was carried out in 1999-2002. Samples measured were fly ash, sand and tuff. Laboratories used different experimental equipment and procedures. Corrections for blank, spectral interference, self-absorption and coincidence summing effects were applied in most cases. The agreement between results was within 15-20%, most often within the reported uncertainties. Several general conclusions can be drawn regarding procedures correctness, uncertainty budget, secular equilibrium condition, and radionuclide representativeness in each natural series. Further studies are needed to draw more specific conclusions.

Construction Materials↗
PubMedDate not supplied

Development and characterisation of a head calibration phantom for in vivo measurements of actinides.

The investigation of actinides' internal contamination in human body makes use of a variety of techniques. In large scale screening the technique of "in vivo" evaluation of bone 241Am burden via the determination of the nuclide activity in the skull is often used. For this purpose, adequate calibration procedures and standard phantoms are needed. The present paper summarises the studies and technical procedures followed for the development of a calibration phantom based on a commercial Alderson angiographic head in which a set of 24 241Am point sources were embedded. A theoretical study was first carried out, at the ENEA Institute for Radiation Protection, using the MCNP4-B Monte Carlo code to determine the point source distribution that closely approximates a homogeneous bone contamination. The numerical models were also used to evaluate the resulting degree of approximation. The point sources were prepared at the ENEA National Metrology Institute for ionising radiation quantities and were traceable to the Italian national standard of radionuclide activity. The sources were prepared by quantitatively dispensing a liquid solution onto a plastic disc. The activity of each source was checked by gamma-ray spectrometry and the reproducibility of the activity values was determined. Each source was then placed in the optimum position in the skull, given by the Monte Carlo modelling, by a precision mechanical device. The phantom was finally used to calibrate a whole body counter operating at the ENEA Institute for Radiation Protection. The paper reports the main theoretical and experimental aspects of this work, and also discusses the results of the first calibrations.

Actinoid Series Elements↗