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Biomedical subjects

H Navarro

Publications and source records attributed to H Navarro.

28 records · Page 2Linked to original sources
PubMed1992

Effects of nicarbazin on sugar intestinal absorption in rabbits.

Nicarbazin is an anticoccidial drug, used mainly in birds, which can also be used in rabbits. It has been shown to produce several effects, such as inhibition of growth and feed efficiency in poultry. The aim of the present work was to determine whether nicarbazin alters intestinal absorption of sugar. Results obtained show that nicarbazin decreases D-galactose accumulation in the jejunal tissue and increases mucosal to serosal transepithelial fluxes of this sugar, in both cases in a dose-dependent way. Furthermore, nicarbazin seems not to modify the sugar diffusion across the intestinal epithelium. The drug also stimulates the sugar uptake in brush border and basolateral membrane vesicles. The results suggest that in rabbits nicarbazin increases sugar intestinal absorption mediated by carriers.

Animals↗
PubMed1992

Effect of erythromycin on L-threonine transport in rabbit jejunum in vitro.

Several antibiotics characterized by different molecular structures are known to affect some intestinal activities. Some of them have been described as inhibitors of the intestinal sugar and amino acid transport with different mechanisms. Erythromycin (EM) is a macrolide antibiotic acting as a motilin agonist and thus stimulating the gastrointestinal motor activity. Since several substances which increase the motor activity of the gastrointestinal tract may produce effects on the intestinal absorption of nutrients, the present study has been carried out to determine whether erythromycin affects the L-threonine intestinal absorption. The results obtained indicate that erythromycin diminishes the L-threonine intestinal transport, probably at the mucosal border level. Two groups of experiments carried out, with Na(+)-deprived medium and ouabain-enriched medium, might indicate that erythromycin action could be due to either a direct or an indirect action on the Na(+)-dependent L-threonine transport located in the brush border.

Animals↗
PubMed1992

Effects of nicarbazin on intestinal digestion and absorption of nutrients in the rabbit.

Nicarbazin is an anticoccidial drug, used mainly in birds, which has shown several other effects including inhibition of growth and feed efficiency in poultry, and stimulation of sugar and amino acid intestinal absorption in rabbit. The present work was designed to determine whether nicarbazin added to the feed, affects growth and feed intake in rabbit, and whether the continuous ingestion of nicarbazin can alter the mechanisms of intestinal nutrient absorption or digestion in this species. Nicarbazin, administered at the recommended dose (125 ppm) had no harmful effects either on growth or on feed intake of animals. After treatment for one month with nicarbazin at the dose of 125 ppm added to the feed, rabbits displayed a higher transport ability of both D-glucose and L-leucine through the enterocyte plasma membranes than did untreated rabbits. These animals also showed higher specific activities of two brush-border enzymes, sucrase and aminopeptidase N, than the control animals.

Administration, Oral↗
PubMed1990

Effect of time and temperature of incubation of heparinized caprine blood on concentrations of progesterone detected in plasma.

Blood samples from 12 pregnant does were collected in flasks containing heparin. Each sample was divided into 31 aliquots, the first of which was immediately centrifuged for plasma separation. Fifteen of the remaining aliquots from each goat were kept at 17 degrees C, while the remaining is were refrigerated at 4 degrees C. Centrifugation of these aliquots was carried out at half-hour intervals until completion of 6 h, and then at 8, 12 and 24 h post collection. The mean concentration of progesterone in the aliquots centrifuged initially was 4.0 +/- 0.3 ng/ml, and it was not significantly altered during incubation of the blood at 17 degrees C. In contrast, the concentrations of progesterone increased significantly to 5.0 +/- 0.3 (P < 0.05) during the first hour of incubation at 4 degrees C, remaining elevated most of the time. The stability of progesterone during incubation of heparinized caprine blood at 17 degrees C indicates that immediate centrifugation is not necessary. Refrigeration during the storage of blood samples is not recommended since progesterone levels are altered, probably due to separation of progesterone from the membranes of red blood cells during the hemolysis that is caused by incubation at low temperatures.

Journal Article↗
PubMed1975

Comatose state maintained during eight years following a vascular ponto-mesencephalic lesion.

A 24-year-old man survived for 8 years after a vascular lesion of the pons and midbrain. During these years a subresponsive comatose state with neurological signs extending from the oculomotor nuclei to the trigeminal and facial nuclei levels was present. A decorticated type of rigidity, with bilateral paralysis of the limbs accompanied by pyramidal signs, was also present. The EEG during the first months showed slow activity which afterwards gradually changed towards fast and alpha activities, maintained in the course of the years. The pathological diagnosis was a fibrous endarteritis, mainly in the territory of the basilar and vertebral arteries. The pons and midbrain, presenting a large cystic infarct, were serially studied to determine the anatomical extent of the lesion. After reviewing other examples from the literature, the clinical features of our case are discussed. The evolution of the EEG is related to different structures of the ponto-mesencephalic region with different functional activities.

Adult↗
PubMedDate not supplied

Effect of erythromycin on D-galactose absorption and sucrase activity in rabbit jejunum.

Erythromycin, an antibiotic used in the treatment of infectious diseases, produces gastrointestinal side effects such as diarrhea. The mechanisms by which erythromycin produces these effects are not known. However, erythromycin has been shown to increase gastrointestinal motor activity and to inhibit intestinal neutral amino acid absorption. Both effects could contribute to the gastrointestinal side effects observed. Because the intestinal systems of amino acid and sugar transport present similar characteristics, the aim of the present work was to determine whether erythromycin also alters D-galactose absorption and sucrase activity in rabbit jejunum. The results show that erythromycin diminishes intestinal D-galactose absorption. This effect seems to be due to an action mainly located on the Na(+)-dependent sugar transport of the mucosal border of the intestinal epithelium. Erythromycin also inhibits the Na(+)-K+ ATPase activity of the enterocyte, which might explain the inhibition of the D-galactose Na(+)-dependent transport. However, a direct action of the erythromycin molecule on the Na(+)-dependent carrier cannot be excluded. Erythromycin did not alter sucrase activity.

Animals↗