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Biomedical subjects

A Bertuzzi

Publications and source records attributed to A Bertuzzi.

61 records · Page 4Linked to original sources
PubMedDate not supplied

Tissue uptake and oxidation of disodium sebacate in man.

In order to better ascertain its possible use as an alternative fuel substrate in total parenteral nutrition, sebacate (Sb) metabolism was studied in seven overnight-fasting healthy male volunteers, who received a constant iv infusion (99 mmoles over 8 hours) of disodium sebacate. Sb oxidation rate was determined using an isotopic sebacate (disodic salt of (1-10)14C-sebacic acid) infusion (100 mu Ci from the fourth to the eighth hour of the cold sebacate infusion). Blood samples were collected during and after sebacate infusion at intervals of 30 minutes and Sb serum concentrations were determined by high performance liquid chromatography. Excreted radioactivity (mu Ci/min) was measured by bubbling the expired air into an apparatus containing 3 mEq hyamine to trap CO2 from a 20-L Douglas-bag. CO2 production and O2 consumption were measured before and at 4 and 8 hours after starting the infusion. Twenty-four hour nitrogen excretion with urine was obtained. The RQ and the percent of calories derived from lipid oxidation were calculated by indirect calorimetry. The Sb serum level at the plateau phase was (mean +/- SD) 4.54 +/- 0.71 mumole/mL, the overall rate of tissue uptake was 180.89 +/- 4.50 mumole/min, and the percent oxidation was 6.14 +/- 0.44%. At the end of Sb infusion the RQ dropped to 0.839 +/- 0.043, the percent of calories due to sebacate oxidation was 1.59 +/- 0.52%, and the calories derived from lipids increased to 37.77 +/- 12.90%. These data show that a definite amount of the sebacate infused is oxidized in human tissues.

Adipates↗
PubMedDate not supplied

Pharmacokinetic analysis of dodecanedioic acid in humans from bolus data.

BACKGROUND: Excretion and tissue uptake of dodecanedioic acid (C12), a proposed alternative fuel substrate, was investigated in humans by bolus experiments. METHODS: Seven overnight-fasting healthy male volunteers received i.v. a bolus (1 g) of C12. Blood samples were collected after C12 administration at intervals of 15 minutes, and C12 serum concentration was measured by high-performance liquid chromatography. C12 excretion in 24-hour urine was measured. Binding of C12 in human serum was determined in separate equilibrium dialysis experiments by means of an isotopic compound (disodic salt of (1,12)14C-dodecanedioic acid). A two-compartment model was used for describing C12 kinetics. RESULTS: The excreted amount of C12 in 24-hour urine was found to be, on the average, 1.62% of administered dose. The apparent number of binding sites per albumin molecule was 3.1 +/- 0.2 (estimate +/- SE) with an affinity constant of 6.4 +/- 1.8 mM-1. The distribution volume of central compartment was 5.56 +/- 3.13 L and that of peripheral compartment was 87.4 +/- 30.4 L. The rate constant of exchange between compartments was 4.60 +/- 3.50 L/min, that or urinary excretion 25.6 +2- 15.5 mL/min, and that of tissue uptake 2.17 +/- 0.86 L/min. CONCLUSIONS: These results are promising for C12 utilization in parenteral nutrition, because C12 elimination in urine is low whereas tissue uptake appears to be rather efficient.

Binding Sites↗
PubMedDate not supplied

Pharmacokinetics of sebacic acid in rats.

The pharmacokinetics of disodium sebacate (Sb) was studied in Wistar rats of both sexes. Sebacate was administered either as intra-peritoneal (i.p.) bolus (six doses ranging from 10 mg to 320 mg) or as oral bolus (two doses: 80 and 160 mg). Plasma and urinary concentrations of Sb and urinary concentrations of Sb and its products of beta-oxidation (suberic and adipic acids) were measured by an improved method using gas-liquid chromatography/mass-spectrometry. A single compartment with two linear elimination routes was selected after no increase in significance was shown by an additional compartment and after a saturable mechanism was found to be unsuitable. Both renal and non-renal elimination parameters were obtained by Marquardt non linear fitting of plasma concentrations together with urinary elimination. The data reported are calculated from the analysis on the whole population of rats and referred to an average body weight (bw) of 100 g. The Sb half-time was 31.5 min. The tissue elimination rate was 0.0122 min-1. The overall volume of distribution was found to be 26.817 ml/100 g bw. The renal clearance was 0.291 ml/min/100 g of bw, which is much less than the value of GFR reported in literature (about 1 ml/min/100 g bw), suggesting the presence of Sb reabsorption from the ultrafiltrate. The value of Sb renal clearance was found to be a concentration-independent function, suggesting the presence of a passive back-diffusion. The relative bioavailability of the oral form compared to the i.p. form was 69.09%, showing a good absorption of the drug.

Administration, Oral↗
PubMedDate not supplied

Randomized study of single vs double exposure in myopic PRK.

Multizone PRK has been suggested to increase the predictability of higher myopic corrections. The technique consists of dividing the intended correction between two or three different concentric ablation zones, achieving less depth and a smoother ablation profile. We randomized 24 eyes with refractions between -6.00 and -9.00 D for single or double ablation-zone PRK. At 1 year no significant difference in refraction and complications were found between the two treatments. The multizone PRK technique may be safely employed to reduce the maximum central depth of the keratectomy in high myopics.

Adolescent↗
PubMedDate not supplied

Efficacy of corticosteroids in reversing regression after myopic photorefractive keratectomy.

Topical corticosteroids are given commonly after photorefractive keratectomy (PRK). We present six eyes treated for correction of myopia ranging between -6.00 and -8.00 D, to whom corticosteroid drops were given and then suspended. Each eye had an increase in myopia with a mean of 2.00 D (range 1.00 to 3.50 D). All were then treated with topical dexamethasone (0.1%) four times per day for at least 15 days, and all showed decreases in myopia with partial or complete recovery of the intended correction (mean: 1.625 D; range 1.00 to 3.50 D). All of these refractive variations were documented by corneal topography. In one eye, refractive and topographic variations were detected by 3 days after corticosteroid treatment was initiated and they increased for 15 days. We believe corticosteroids can modulate refractive changes after PRK.

Adult↗