PubMed Health⌕ Search

Biomedical subjects

M J Diez

Publications and source records attributed to M J Diez.

At least 19 recordsLinked to original sources
PubMed2002

Therapeutic effects of psyllium in type 2 diabetic patients.

OBJECTIVE: The aim of this study was to evaluate the effects of psyllium in type 2 diabetic patients. DESIGN: The study included three phases: phase 1 (1 week), phase 2 (treatment, 14 g fibre/day, 6 weeks) and phase 3 (4 weeks). At the end of each phase a clinical evaluation was performed after the ingestion of a test breakfast of 1824.2 kJ (436 kcal). Measurements included concentrations of blood glucose, insulin, fructosamine, GHbA(1c), C-peptide and 24 h urinary glucose excretion. In addition, uric acid, cholesterol and several mineral and vitamin concentrations were also evaluated. SETTING: The study was performed at the Department of Pharmacology, Toxicology and Nursing at the University of León (Spain). SUBJECTS: Twenty type 2 diabetic patients (12 men and 8 women) participated in the study with a mean age of 67.4 y for men and 66 y for women. The mean body mass index of men was 28.2 kg/m(2) and that of women 25.9 kg/m(2). RESULTS: Glucose absorption decreased significantly in the presence of psyllium (12.2%); this reduction is not associated with an important change in insulin levels (5%). GHbA(1c), C-peptide and 24 h urinary glucose excretion decreased (3.8, 14.9 and 22.5%, respectively) during the treatment with fibre (no significant differences) as well as fructosamine (10.9%, significant differences). Psyllium also reduced total and LDL cholesterol (7.7 and 9.2%, respectively, significant differences), and uric acid (10%, significant difference). Minerals and vitamins did not show important changes, except sodium that increased significantly after psyllium administration. CONCLUSIONS: The results obtained indicate a beneficial therapeutic effect of psyllium (Plantaben) in the metabolic control of type 2 diabetics as well as in lowering the risk of coronary heart disease. We also conclude that consumption of this fibre does not adversely affect either mineral or vitamin A and E concentrations. Finally, for a greater effectiveness, psyllium treatment should be individually evaluated.

Aged↗
PubMed2001

Effects of ispaghula husk and guar gum on postprandial glucose and insulin concentrations in healthy subjects.

OBJECTIVE: The aim of this study was to evaluate, under the same experimental conditions and in the same subjects, the effects of ispaghula husk and guar gum on postprandial glucose and insulin concentrations in healthy female subjects. DESIGN: An oral glucose load with and without fiber was administered in the morning after an overnight fast. The study of the fiber effect was planned according to a randomized and cross-over design. SETTING: The study was performed at the Department of Pharmacology, Toxicology and Nursing at the University of León (Spain). SUBJECTS: Ten healthy female volunteers aged 30-48 y with normal body mass indices participated in this study. RESULTS: A significant decrease in mean serum insulin concentrations was observed from 30 to 90 min in the presence of both fibers. The area under the insulin curve was significantly reduced by 36.1% for ispaghula husk and 39.4% for guar gum. The area under the glucose curve was reduced by 11.1% (significant difference) for ispaghula husk and 2.6% for guar gum (no significant difference). CONCLUSIONS: According to the results obtained in this study, the administration of ispaghula husk may be beneficial due to its ability to reduce glucose postprandial concentration and especially insulin requirements. Individualization of the treatment would be advisable due to large individual variations observed in glycemic and insulinemic postprandial responses.

Adult↗
PubMed2000

Influence of two dietary fibers in the oral bioavailability and other pharmacokinetic parameters of ethinyloestradiol.

Dietary fibers are widely used in hypoglycaemic, hypolipidemic, slimming diets. It is probable that their ingestion coincides with the oral administration of drugs and a modification of their pharmacokinetics can appear. In the present study, the influence of two soluble fibers (guar gum and psyllium) was evaluated on the pharmacokinetics of ethinyloestradiol (EE) when they were administered together to female rabbits via the oral route. Three groups of rabbits were used. All animals received 1 mg/kg of EE; this compound was administered alone in the control group and with 3.5 g of guar gum or psyllium in the other two groups. When guar gum was administered, there was a decrease in the extent of EE absorbed, but no change was observed in the rate of absorption. When psyllium was administered, the extent of EE absorbed increased slightly and the rate of absorption was slower.

Administration, Oral↗
PubMed1998

Bioavailability of levamisole after intramuscular and oral administration in sheep.

AIMS: To determine the bioavailability of levamisole in sheep. METHODS: Levamisole was administered to three groups of six Merino sheep orally and intramuscularly at three dose levels of 5, 7.5 and 10 mg/kg. There was a washout period of 1 week between treatments. Blood samples were collected by jugular venepuncture and plasma was separated immediately by centrifugation and stored at 20 degrees C until analysed. The levamisole concentration in plasma was determined by high performance liquid chromatography with a U.V. detection method. Individual plasma levamisole concentration-time data were analysed using the compartmental method. RESULTS: The values obtained for k(a), C(max), t(max) and F show a moderate rate and extent of absorption after oral administration of levamisole while, after intramuscular administration, these values demonstrate a high rate and extent of absorption of levamisole. The intramuscular bioavailability was higher than the oral bioavailability (rate of absorption three-fold faster, extent of absorption 25-33% higher and C(max) two-fold higher). The Friedman test involving dose and route of administration showed that the route of administration affects k(a), C(max), t(max) and F; significant differences were found in these parameters. CLINICAL RELEVANCE: On the basis of these data, the recommended routes for the administration of levamisole in sheep are oral for gastro-intestinal nematodiasis and intramuscular for extragastric nematodiasis.

Journal Article↗
PubMed1998

Organochlorine pesticide residues in muscle tissue of rainbow trout, Oncorhynchus mykiss, taken from four fish farms in León, Spain.

Levels of nine organochlorine pesticides (lindane, heptachlor epoxide, aldrin, dieldrin, endrin, o,p'-TDE, p,p'-TDE, p,p'-DDE and p,p'-DDT) were determined in muscle samples of rainbow trout, Onchorhynchus mykiss, collected from four fish farms in the province of León, in the north-west of Spain (Europe). The highest incidence percentage was for lindane (67.5%) and heptachlor epoxide (55.0%). Organochlorine residue levels detected contributed slightly to acceptable daily intakes (ADIs) established by the Food and Agriculture Organization of the United Nations and the World Health Organization (lindane 0.22-2.3%; sigma DDT 0.05-0.46%; heptachlor epoxide 10.0-71.4% and sigma dieldrin 16.7-33.3% assuming 300 g of trout muscle as a mean daily intake). The highest concentration found was for heptachlor epoxide (0.043 microgram/g).

Aldrin↗
PubMed1998

Influence of two commercial fibers in the pharmacokinetics of ethinylestradiol in rabbits.

Fiber formulations are used in human nutrition owing to their beneficial properties for health. It is probable that ingestion of fiber coincides with the oral administration of drugs, and a modification of its oral absorption, and therefore of its pharmacokinetics, can appear. In the present study, the compartmental and noncompartmental pharmacokinetic parameters of ethinylestradiol (EE) in rabbits after oral administration were determined. It was also studied whether the presence of two different fiber formulations [A, wheat bran (76.5%), fruit fiber (12%) and guar gum (2%) and B, Plantago ovata seeds (65%) and P. ovata seed cuticles (2.2%)] in the gastrointestinal tract modified the pharmacokinetics of EE when administered at the same time. Three groups of rabbits were used: control, fiber A and fiber B. The animals in all three groups received 1 mg/kg b. wt. EE. The estrogen was administered alone in the control group and in the presence of 4 g of fiber A and fiber B, respectively, in the other two groups. After compartmental (two-compartment open model) and noncompartmental analyses of plasma concentrations, statistical analysis revealed that the presence of fiber (both A and B) decreased between 29% and 35% the extent of EE absorbed (represented by the pharmacokinetic parameters area under the curve and the maximum plasma concentration) without affecting the rate of the absorption process (represented by the time to reach maximum concentration and the absorption rate constant).

Administration, Oral↗
PubMed1997

Study of the pharmacokinetic interaction between ethinylestradiol and amoxicillin in rabbits.

Several antibiotics have been implicated in oral contraception failure when they are administered at the same time as the oral contraceptive (OC) pill. In the present paper, a study about amoxicillin-ethinylestradiol (EE2) pharmacokinetic potential interaction was studied. Two rabbit groups were utilized, the first group received amoxicillin (10 mg/kg) and EE2 (30, 50 and 100 micrograms/kg, respectively), both by intravenous (i.v.) route. The second group received amoxicillin (oral route, 10 mg/kg/day) and EE2 (i.v. route, 100 mu/kg) on day 1, 4 and 8 of antibiotic treatment, respectively. After compartmental (two-compartment open model) and non-compartmental analysis of plasma concentrations, the statistical study (ANOVA p < or = 0.05) revealed that the presence of amoxicillin did not modify the EE2 distribution and elimination pharmacokinetic parameters (by comparison with those obtained in a previous study where EE2 was administered alone). There also were no significant differences with the time of amoxicillin oral treatment.

Administration, Oral↗
PubMed1997

Pharmacokinetics of levamisole in sheep after intravenous administration.

The pharmacokinetics of levamisole at doses of 5, 7.5 and 10 mg/kg were determined after its intravenous administration to eighteen healthy Merino sheep. Using compartmental analysis, the disposition of the drug best fitted a two-compartmental open model. The mean values for the compartmental volume of distribution at steady state (Vss) were 2.034 +/- 0.23 I, 2.347 +/- 0.720 and 2.001 +/- 0.367 I/kg for each dose, respectively, and values obtained using the statistical moment theory were 2.141 +/- 0.269,2.390 +/- 0.536 and 2.140 +/- 0.345 l/kg for each dose, respectively. There were no dose-related differences (one-way ANOVA) in the constants describing distribution and elimination phases (alpha and beta) or Vss, but significant differences were detected in the total body clearance (Cl) and the area under the plasma concentration-time curve (AUC). After non-compartmental analysis, no significant differences were found when the parameters lambda (the linear terminal slope) and Vss were compared, but significant differences were detected in Cl and AUC. There were no significant differences between the values obtained using the compartmental and non-compartmental analysis when lambda -beta, Cl, Vss, and AUC were compared.

Journal Article↗
PubMed1997

Plasma protein binding of levamisole in several species.

The binding of levamisole to total plasma proteins of 6 animal species was determined in vitro by equilibrium dialysis. The percentage of bound drug protein was independent of levamisole concentration within the range studied, 5-50 micrograms/ml (ANOVA). Levamisole was bound to a low extent to plasma proteins of each animal species (19.40-25.91%). There were significant differences in the extent of levamisole binding among species (ANOVA). Owing to the low degree of protein binding and the high volume of distribution of levamisole, the variations in protein binding due to different factors would not be of major clinical importance in its therapeutic application.

Adjuvants, Immunologic↗
PubMed1996

Organochlorine pesticide residues in bovine milk from Leon (Spain).

Residue levels of the organochlorine pesticides (alpha-HCH, lindane, heptachlor-epoxide, aldrin, endrin, dieldrin, o,p'-TDE, p,p'-TDE, p,p'-DDE and p,p'-DDT) were determined in raw bovine milk and compared with the maximum levels allowed by the European Union (EU) in these foods. The highest incidence percentage of the ten insecticides measured was for lindane, followed by alpha-HCH and aldrin. Moreover, the highest mean residue level was for alpha-HCH. None of the samples analyzed exceeded the maximum levels allowed by the EU.

Animals↗
PubMed1996

Pharmacokinetics of ethinyloestradiol in rabbits after intravenous administration.

The pharmacokinetics of ethinyloestradiol (EE2) after intravenous administration of 30, 50 and 100 micrograms.kg-1 was investigated in rabbits. A high-performance liquid chromatographic (HPLC) method with electrochemical (EC) detection was used to measure EE2 in plasma samples in order to avoid the interferences of natural oestrogens. After compartmental analysis, the disposition of EE2 was well described by a two-compartmental open model with mean values of: alpha = 0.3448 +/- 0.2922, 0.1965 +/- 0.1755, 0.3058 +/- 0.1225 min-1, and beta = 0.0137 +/- 0.0018, 0.0140 +/- 0.0065, 0.0198 +/- 0.0066 min-1, for the three doses studied, respectively. There were no dose-related differences (ANOVA, P < 0.05) in a, b or Vss, but significant differences were detected in clearance (90.9 +/- 18.7; 80.6 +/- 17.6; 116.3 +/- 21.5 ml.min-1.kg-1) between the 100 micrograms.kg-1 group and lower dose groups. The AUC increased significantly with the doses (341.7 +/- 67.1; 645.8 +/- 143.9; 892.2 +/- 211.9 ng.min.ml-1). After non-compartmental analysis there were no significant differences in lambda, MRT or Vss as a function of dose, but these differences were significant when Cl or AUC were compared. There were no significant differences in AUC or Cl values obtained by compartmental and non-compartmental analysis.

Animals↗
PubMed1994

Bioavailability of levamisole administered by subcutaneous and oral routes in rabbits.

The bioavailability of levamisole in rabbits was determined after subcutaneous and oral administration at three dose levels of 12.5, 16.0 and 20.0 mg/kg. After non-compartmental analysis the mean values obtained were: Cmax = 3.54, 4.51 and 5.39 micrograms/ml; tmax = 12.0, 22.0 and 20.0 min; F = 134.8, 105.4 and 124.1% after subcutaneous administration for each dose, respectively, and Cmax = 0.71, 1.32 and 1.77 micrograms/ml; tmax = 46.0, 96.0 and 84.0 min; F = 53.0, 62.0 and 80.7% after oral administration. The extent and rate of absorption from the two routes differed significantly, except for tmax at the 12.5 mg/kg dose. After compartmental analysis the pharmacokinetics of levamisole was characteristic of a two-compartment open model in 13 rabbits and of a one-compartment open model in two rabbits after subcutaneous administration, while it was two compartmental in nine and one compartmental in six rabbits after oral administration. The ka values were 0.321, 0.145 and 0.145 min-1 after subcutaneous administration and 0.054, 0.023 and 0.027 min-1 after oral administration. There were no significant differences between the values of Cmax, tmax and AUC calculated by compartmental and non-compartmental analysis.

Absorption↗
PubMed1993

Rapid high-performance liquid chromatographic assay of ethynyloestradiol in rabbit plasma.

A method for the determination of ethynyloestradiol in samples of rabbit plasma containing pentobarbital and heparin, the former used as an anaesthetic and the latter as an anticoagulant, has been developed. Quantification was carried out using a reversed-phase high-performance liquid chromatographic (HPLC) method in isocratic mode at room temperature, with electrochemical detection at an applied potential of +1 V vs. Ag/AgCl. Under these conditions, the retention time for ethynyloestradiol was ca. 2.9 min, the average recovery from plasma was 74.5%, and the limit of detection was 10 pg, corresponding to a plasma concentration of 50 pg/ml using 1 ml of plasma. Natural oestrogens, oestriol, oestradiol and oestrone showed peaks that did not interfere with ethynyloestradiol, and retention times of ca. 0.8, 2.4 and 3.4 min, respectively.

Animals↗
PubMed1992

Pharmacokinetics of levamisole in rabbits after intravenous administration.

A compartmental and non-compartmental pharmacokinetic study was carried out on rabbits after intravenous (i.v.) administration of levamisole at the three dose rates: 12.5, 16.0 and 20.0 mg/kg body weight. Using compartmental analysis, the disposition of levamisole best fitted a two-compartmental open model with mean values of alpha = 0.1278, 0.1019 and 0.1282 min-1; beta = 0.0139, 0.0126 and 0.0124 min-1; A = 6.24, 5.27 and 10.58 micrograms/ml and B = 2.14, 3.83 and 5.08 micrograms/ml for each dose, respectively. The statistical moment theory was mainly used for non-compartmental analysis. Values for mean residence time (MRT) of 69.2, 71.7 and 73.1 min were obtained for each dose. The mean values for volume of distribution at steady state (Vd(ss)), determined by compartmental analysis, were 3879, 3279 and 2735 ml/kg for each dose, and values obtained using the statistical moment theory were 3760, 3015 and 2943 ml/kg; there were no statistically significant differences using Student's paired t-test. Identical conclusions were obtained using both methods when the parameters beta, AUC and Cl were compared.

Animals↗