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Biomedical subjects

E Savio

Publications and source records attributed to E Savio.

14 recordsLinked to original sources

Intraocular pressure and progression of visual field damage.

Contradicting results concerning IOP control and visual field deterioration are presented. Some of these inconsistencies may be due to the statistical method of analysis. Sixty POAG patients with a perimetric follow-up over 3 years were selected. Mean and maximum IOPs were considered during the same period. The patients were divided into two groups according to the IOP control (well controlled or poorly controlled). Visual field progression was defined as a reduction in sensitivity over the fifth percentile in more than four points. Mean IOPs were not significantly different in the group of patients with a visual field deterioration compared to the stable ones, but the percentage of patients with a visual field deterioration was significantly higher in patients with higher IOPs. This holds especially true if IOP below 16 mmHg (G) is considered the 'target pressure'. IOP reduction seems to play an essential role in visual field progression. In glaucomatous patients, a strict (<16 mmHg (G)) might be necessary.

Disease Progression↗

Lipidic matrix of albendazole: an alternative for systemic infections.

Albendazole is a poorly water soluble drug, with low oral bioavailability, used in pharmacological treatment of a systemic disease as hydatid parasitosis. Lipidic matrices of Gelucires (44/14 and 35/02) were developed. After "in vitro" studies, one formulation was chosen for a single dose study in 8 healthy volunteers, with a cross-over and randomised design, taking a commercially available tablet as reference. Drug absorption was followed by albendazole sulphoxide dosage in urine by high pressure liquid chromatography. Neither albendazole nor albendazole sulphoxide were recovered in urine after tablet administration while 0.18% (+/- 0.06) of dose was recovered after lipidic matrix administration in the first 24 hours. Besides ageing control were performed up to 18 months post-elaboration. Lipidic matrix with Gelucire 44/14 was revealed as a promising attempt for oral pharmaceutical form in albendazole systemic treatment.

Administration, Oral↗

Lipidic matrix of albendazole sulphoxide: is it an alternative for systemic infections?

As albendazole sulphoxide (ABZS) shows better dissolution properties than albendazole (ABZ), a lipidic matrix with this drug was formulated in order to evaluate if its absorption and so systemic infection chemotherapy could be improved. A cross-over, randomised study in 8 healthy volunteers was carried out, after single administration of 1 g of albendazole or albendazole sulphoxide in lipidic matrix of Gelucire 44/14 (ABZLM and ABZSLM). Absorption was followed performing albendazole sulphoxide dosage in urine samples by high pressure liquid chromatography analysis, during 48 hours. Significant differences were found (p = 0.02) between the urinary recoveries (% E48), being 1.74% and 0.19% the percentage of dose recovered when ABZSLM or of ABZLM were respectively administered. In a previous study of our group similar values were obtained of urinary recovery percentages after albendazole sulphoxide powder administered to another group of healthy volunteers. Lipidic matrix does not improve the physicochemical properties of albendazole sulphoxide powder.

Adult↗

Clinical features, treatment and outcome in a series of 93 patients with low-grade gastric MALT lymphoma.

The purpose of this paper is to report the clinical characteristics and treatment outcome following different therapeutic approaches in a large series of patients with primary low-grade MALT lymphoma of the stomach. A total of ninety-three patients (median age 63 years) were reviewed. The patients were treated by different modalities (local treatment alone, combined treatment, chemotherapy, antibiotics alone); seven patients refused any treatment. The antibiotic-treated group of patients was prospectively followed with regular endoscopic biopsies, and their responses were histologically evaluated. The 5-years projected overall survival is 82% (95% C.I.; 67%-91%) in the series as a whole. Second tumors were observed in 21.5% of the patients in this series (95% CI 14%v to 31%). There was no apparent difference in overall survival and event-free survival between patients who received different treatments. In the antibiotic-treated group histologic regression of MALT lymphoma was documented in 67% of patients (95% CI 51% to 80%). In conclusion the indolent nature of the disease justifies a conservative approach. The use of antibiotics as first-line therapy may avert or at least postpone the indication for surgical resection in the majority of patients.

Adult↗

Assessment of the diagnostic value of 99mTc-radiolabelled specific antibodies in experimental hydatidosis.

We assessed the potential of 99mTc labelled specific polyclonal antibodies (99mTc-PoAb) for the diagnosis of hydatid disease by immunoscintigraphy. Experimentally infected mice and rabbits were used for this purpose. A specific rabbit antibody recognizing total somatic antigen from hydatid membranes (HCMA) was obtained. PoAb biological activity before labelling was checked according to Barbieri et al. 99mTc-PoAb labelling was performed according to Thakur et al.; the radiochemical purity was higher than 90%. The following studies of 99mTc-PoAb were made: post-labelling biological activity; in vitro stability; blood and renal kinetics in normal mice up to 24 hours after intravenous (i.v.) and intraperitoneal (i.p.) administration; biodistribution in normal and infected mice after i.p. or i.v. injection, and in rabbits after i.v. administration. Biodistribution studies in normal mice, after both administration routes, showed considerable hepatic uptake of activity. An important uptake in cysts after i.p. administration in mice, indicating successful targeting, was also confirmed by autoradiography images. Intravenously administered 99mTc PoAb was not significantly targeted to peritoneal cysts in either animal species, due to inherent limitations to these animal models. Results obtained with i.p. administration suggest that specific hydatid imaging may be possible. Both the mice and rabbit models revealed hepatic uptake which, combined with the short isotope half-life, prevent the drawing of any final conclusions regarding the usefulness of 99mTc-labelling in hydatid disease.

Animals↗

Ovine toxoplasmosis: seroconversion during pregnancy and lamb birth rate in Uruguayan sheep flocks.

Specific anti-Toxoplasma gondii antibodies were analyzed by latex agglutination during the 5 months of pregnancy in the serum of sheep from two flocks in the Uruguayan north-west: one flock (79 sheep) kept under an intensive management system and the other (494 sheep) kept under an extensive management system. Titers obtained using the latex test correlated with those obtained by indirect immunofluorescence. Pregnancy was confirmed by laparoscopy in all sheep from the smaller flock and by determination of serum progesterone levels in the seroconverted sheep from the larger flock. The percentage of sheep originally exhibiting significant serum levels of anti-T. gondii antibodies (13.9% in the smaller flock and 28.5% in the larger one) as well as the observed levels of seroconversion (22.8% and 7.7%, respectively), indicated a high prevalence of this infection in the north-west of Uruguay. In addition, birth rates of seroconverted sheep in the larger flock were significantly different from those of non-seroconverted animals. These results, although preliminary, suggest that Toxoplasma infection would produce considerable economic losses in extensive ovine production in Uruguay.

Animal Husbandry↗

Linear relationships in systems with non linear kinetics.

The elimination rate of drug from a capacity-limited one-compartment model can be expressed by equation (1): [formula: see text] Traditionally equation (1) was linearized according to equation (2): [formula: see text] Here, an alternative linear relationships between concentration and the area under the curve of C/(Km + c]) is proposed: [formula: see text] By iteration of Km into equation (3) until the statistic of analysis of variance for the regression is maximized, both Km and Vmax can be obtained. Several cases were considered: a) Intravenous bolus (single dose): Km (mg/L), Vmax (mg/L h), Vd (L) and V (mg/h) can be estimated. b) Extravascular administration (single dose): by the method of residuals it is possible to make additional estimations of FD/Vd (mg/L) and Ka (1/h). c) Bioequivalence studies: with parameters obtained at single dose, the simulated levels at steady-state are considered for the bioequivalence assessments. d) Km, Vmax estimation with two (C,t) points (single dose): double iteration (Km values and interpolated fictitious third points) are needed. e) Multiple dose: [formula: see text] If t2-t1 = T (interval of administration) it is possible to calculate operatives Km, Vmax, FD/Vd and to estimate Css (steady-state concentration). C1 and C2 correspond to different intervals. All the areas were calculated by the trapezoidal rule.

Biological Availability↗

Average parameters in bioavailability studies: an application to slow-release amitriptyline formulation.

In order to assess the extent and the rate of absorption in bioavailability studies, area under the curve (AUC), experimental maximum concentration (Cmax) and experimental time to reach Cmax (Tmax), are used. But when slow-release formulations are considered, the drug concentration-time curves usually show multiple peaks, and it is difficult to compute a Cmax and Tmax value. In case a Cmax value is computed, important variability in this parameter results in high values in the residual variance of the ANOVA test. So in order to decrease the high variability, average parameters: average concentration (Cav), average maximum concentration (Cmax,av) and Cmax,av x 100/Cav (%Cmax,av), are proposed. These new parameters were applied in a bioavailability study of slow-release amitriptyline formulation.

Adult↗