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Biomedical subjects

F Navarro

Publications and source records attributed to F Navarro.

At least 163 records · Page 9Linked to original sources
PubMed1992

Effects of diazepam and D-amphetamine on rhythmic pattern of eye movements in goldfish.

The effects of diazepam and D-amphetamine on spontaneous, vestibular- and visually-induced eye movements were studied in the restrained goldfish. These animals showed a stereotyped pattern of spontaneous eye movements that scanned the visual field in the horizontal plane. Fourier analysis of these eye movements revealed a rhythmic pattern of about 5 cycles per minute, whose frequency increased to double and decreased to half following treatment with diazepam and D-amphetamine, respectively. However, the fast and slow components of vestibulo-ocular and optokinetic reflexes, as well as peculiar blink-like movements, remained unchanged at the same drug doses. These results suggest the presence of a central pattern generator for spontaneous eye movements in the goldfish, whose oscillation frequency is pharmacologically modifiable.

Animals↗
PubMed1992

[Evaluation of two commercial kits for detection of Helicobacter pylori specific antibodies in patients undergoing gastroscopy. A seroprevalence study in an asymptomatic population].

BACKGROUND: We evaluate two different commercially available kits for detecting specific antibodies against Helicobacter pylori in a group of 48 patients with gastrointestinal symptoms that underwent an endoscopic procedure. We also study the seroprevalence of anti-H. pylori antibodies in asimptomatic individuals from our area. METHODS: Microbiologic and pathologic studies were performed in 48 gastric biopsies, in relation with antibodies detection using ELISA (Pylori stat test, Whittaker) and latex particles agglutination (Pyloriset, Orion). We also used ELISA tests for determining the seroprevalence of H. pylori antibodies in 139 asimptomatic individuals. RESULTS: Ninety-four percent of patients with peptic ulcer disease and 81% of patients without peptic ulcer disease but complaining of dyspepsia were infected by H. pylori. None of the patients with normal gastric mucosae was found to be infected. Sensitivity and specificity of ELISA test were 100% and 73%. Latex test sensitivity and specificity were 46% and 82%. The seroprevalence of antibodies among healthy individuals in our area increases with age (19% among children under 9 years of age) and reaches a peak at 40-49 years of age (84%), with a mean value of 60% in all ages' groups. CONCLUSIONS: There is a high correlation between Helicobacter pylori infection and gastric mucosa alterations. The ELISA test is best correlated with other laboratory data used for defining infection. The seroprevalence of H. pylori antibodies is also high, and therefore we recommend that the use of serologic diagnostic test must be highly selective.

Adolescent↗
PubMed1991

[Detection of pneumococcal capsular polysaccharide antigen in urine by counterimmunoelectrophoresis. Technical features and correlation with serotype].

The effectiveness of CIE in detecting capsular polysaccharide antigen of pneumococci in urine is revised. Using CIE, we studied urine samples from 57 patients with systemic pneumococcal infections, proved bacteriologically by means of isolation of the microorganisms from sterile sites. We compare the usefulness of CIE with the microorganism isolation from organic products. We also determine the sensitivity gain after passive diffusion at 4 degrees C and bright blue Coomasie staining (CBB R-250). We correlate the CIE results with the serotype of isolated pneumococci. CIE was positive in 17 of all 35 pneumonia cases (48.6%), in 2 of all 5 bacteremias (40%), 4 of all 15 meningitis (26.7%) and in none of all two peritonitis. Direct urine examination was positive in 12 out of 23 patients with positive CIE (52.2%) and concentrated urine in 22 patients (95.6%). Passive diffusion at 4 degrees C and CBB R-250 stain increases the positive rate of the test. The correlation of serotype with our results is difficult due to the wide variety of serotypes identified. However, particular serotypes such (3, 4 or 8) had been identified with increased sensitivity. Global sensitivity of CIE in detecting capsular polysaccharide antigen in urine samples is not high enough (40.3%), even under the best circumstances. Antigen detection in urine is more sensitive than blood cultures, and therefore we believe that could be used in clinical microbiology laboratories until a more effective method is available.

Antigens, Bacterial↗
PubMed1989

[Reversibility of alcoholic myocardiopathy with abstinence: presentation of 2 cases].

The sustained alcohol intake results in the development of a dilated cardiomyopathy; its pathogenesis and prognostic and evolutive factors have not yet been completely defined. It is classically considered that alcoholic cardiomyopathy has a poor prognosis, as two thirds of patients die within three years. However, in recent years some isolated cases of clinical reversibility after short abstinence periods have been reported without identification of the involved factors. Two chronic alcoholic patients are reported with congestive heart failure at admission; a diagnosis of alcoholic cardiomyopathy was made after cardiac catheterization and endomyocardial biopsy. The morphometric study of endomyocardial biopsy showed a preservation of the myofibrillary fraction with mild fibrosis. The clinical outcome was favorable: after three months of alcoholic abstinence, a complete clinical recovery with definite improvement of echocardiographic parameters and left ventricular ejection fraction in the radionuclide ventriculography were observed. Finally, the factors that appear to be involved in the presence or absence of reversibility of this type of cardiomyopathy are discussed.

Adult↗
PubMed1988

A possible mechanism whereby parathyroid hormone stimulates phospholipid synthesis in canine renal tubules.

Incubation of canine renal cortical tubules with parathyroid hormone and [3H]glycerol stimulated incorporation of tracer into phosphatidylinositol 4-phosphate and decreased phosphatidic acid labelling but did not affect phosphatidylinositol, phosphatidylcholine/phosphatidylserine, phosphatidylethanolamine/phosphatidylglycerol, 1,2-diacyl- or triacylglycerol labelling. The hormone did not change the activity of glycerol 3-phosphate acyltransferase or of phosphatidate phosphohydrolase measured in tubule homogenates. However, parathyroid hormone induced a rapid increase in phosphatidylinositol kinase activity associated with a decrease in Km of the enzyme for ATP in homogenized tubules. These findings suggest a possible mechanism whereby parathyroid hormone increases phospholipid synthesis in the renal cortex.

1-Phosphatidylinositol 4-Kinase↗
PubMed1985

[Treatment of retinal detachment caused by posterior pole dehiscence].

20 eyes have been treated for a retinal detachment due to a posterior pole break. Three successive, different operative techniques were used: macular silastic sponge, vitrectomy plus internal tamponade by silicone oil, vitrectomy plus internal tamponade by air or by a mixture of air 60% and SF6 40%. Macular sponges obtained a good rate of retinal reattachment (83.3%) but fonctionnal results are poor (no measurable visual acuity in the macular break cases). Vitrectomy plus silicone oil does not yield better anatomical results than sponges (66.6% succes rate) but the visual function is better preserved (2 measureable visual acuities on 3 macular break cases). Vitrectomy plus gas gave us the best anatomical (100% success rate) and functional results (4 measurable usual acuities on 6 macular break cases). Retinopexy is not necessary when the vitrectomy-gas technique is used. On the contrary, retinopexy is recommended when the vitrectomy-silicone technique is used in order to remove the silicone oil as safely as possible: this causes a dilemma in the case of a macular break. We think at the present time that vitrectomy-gas is the best way to treat these particular retinal detachments.

Humans↗
PubMed1984

Effect of monodansylcadaverine on the synthesis of phosphatidylinositol by rabbit neutrophils.

The present results show that the addition of monodansylcadaverine to rabbit neutrophils stimulates the incorporation of both [3H]inositol and [3H]glycerol into phosphatidylinositol. Monodansylcadaverine also induces the accumulation of phosphatidylinositol 4-phosphate, phosphatidic acid and diacylglycerol. These effects are all dose-dependent and occur at concentrations of monodansylcadaverine which are known to inhibit receptor-mediated endocytosis. Monodansylcadaverine has not effect on phosphatidylinositol hydrolysis or arachidonic acid release, indicating that it acts by increasing de novo synthesis of phosphatidylinositol but not its turnover. It is proposed that the effects of monodansylcadaverine on receptor-mediated endocytosis are mediated, at least in part, by its perturbing effect on lipid metabolism.

Animals↗
PubMed1984

[Determination of 25-hydroxycholecalciferol in serum].

A precise specific method for measuring 25-hydroxycholecalciferol (25-OH CC) in 2 ml of human serum is described. It includes extraction with acetonitrile, separation with Sep-Pak C-18 cartridges, purification through HPLC and a further quantitation by means of a protein-binding assay. An exhaustive study of this protein-binding method has been performed. The sensitivity of the protein-binding assay is 20 pg/tube and the inter and intra-assay coefficients of variation are 9.6% and 8.7% respectively. The precision of the overall process has been assessed by calculating the inter and intra-assay coefficients of variation, 15.5 and 10.4% respectively. Mean serum value of 25-OH CC in normal subjects (18-50 years old, during spring) is 11.2 +/- 5.5 ng/ml.

Acetonitriles↗
PubMed1984

[Retinal detachments caused by giant tear].

52 eyes in 50 patients have been treated for a retinal detachment with a giant tear extending over at least 70 degrees. 27 eyes had an inverted posterior retinal flap covering the posterior pole. Conventional extraocular surgery was performed on 20 eyes. There was no success in 6 folded cases and a 42,85% success rate in 14 non-folded retinas. Endocular surgery by vitrectomy plus internal tamponade using air or silicone oil was done on 32 eyes with an 87,50% success rate at the end of surgery. Post-operative retinal retraction reduced the success rates to 45,45% for non-folded cases and 52,38% with folded retinas. There is no question in our mind about the value of endocular surgery for folded retinas. We think that endocular surgery is also the best choice for non folded retinas because of the excellent initial results. Secondary retraction phenomena are caused by endocular cellular proliferation and membrane formation and contraction. We presently try to minimize these by avoiding excess cryopexy, performing a vitrectomy as complete as possible and treating the reattached retina as soon as possible by argon laser photocoagulation. An efficient and safe antiproliferative drug is definitely needed.

Adolescent↗