PubMed Health⌕ Search

Biomedical subjects

V Rodriguez

Publications and source records attributed to V Rodriguez.

At least 37 records · Page 2Linked to original sources
PubMed1998

Switching attention without shifting the spotlight object-based attentional modulation of brain potentials.

Although psychophysical evidence for object-based attention has been reported, corresponding studies with event-related potentials (ERPs) are scarce. Here subjects were presented with perceptual fields containing two superimposed objects (transparent surfaces generated by two sets of dots in rigid rotation around fixation, each set of a different color and direction of motion) or only one object (the same dots but either at rest or all rotating in the same direction). Brief (150-msec) rectilinear displacements affected either of the sets at random ISIs of 350 to 550 msec. Attention was directed to one set of dots, guided by color, in order to discriminate the direction of their displacement. Motion-onset ERPs elicited by these displacements were compared for attended and unattended dots. When the perceptual field consisted of two objects, strong suppression of P1 and N1 was obtained in the ERPs associated with the unattended object. No suppression was found with the field containing a single object, although an enhanced selection negativity was found in ERPs associated with attended dots (selected by color). Since the two objects occupied the same region of visual space, the suppression of P1/N1 cannot be explained by the space-based mechanisms but is consistent with object-based attentional selection at early stages of vision. The results highlight the role of perceptual organizations in enabling alternative attentional mechanisms.

Adult↗
PubMed1998

153Sm-EDTMP.

Explore the source record for details and available documents.

Analgesics, Non-Narcotic↗
PubMed1997

A follow-up study of multibacillary Hansen's disease patients treated with multidrug therapy (MDT) or MDT + immunotherapy (IMT).

Multibacillary (MB) leprosy patients treated with multidrug therapy (MDT) or MDT + immunotherapy (IMT) with BCG + heat-killed Mycobacterium leprae were tested annually for their ability to proliferate in vitro to the mycobacterial antigens BCG, M. leprae soluble extract, and intact M. leprae. IgM antibody responses to phenolic glycolipid I (PGL-I) were measured, as well as serum nitrite levels in patients' sera, before, during and after treatment. Patients who received only MDT did not present cellular reactivity to intact M. leprae antigens, in contrast to the results obtained with BCG, which elicited reactivity at time zero, that increased after treatment. Regarding PGL-I antibody variations in relation to the initial value, we observed a statistically significant marked decrease at the end of 2 years which continued to fall in successive evaluations. MB patients showed high initial serum nitrite concentrations which dropped drastically with treatment. This decay was apparently associated with the bacillary load present in these patients. The group submitted to IMT + MDT showed high and long-lasting T-cell responses to mycobacterial antigens in a significant number of initially unresponsive MB patients. There was a marked increase to M. leprae soluble extract and BCG, as well as a more variable response to whole bacilli. The antibody levels in this group of patients are sustained for a somewhat longer period and decreased more slowly during the 5-year follow up.

Antibodies, Bacterial↗
PubMed1997

[Benign glial cysts of the pineal region].

A review of the pertinent literature regarding glial cysts of the pineal region is presented. Various pathogenic factors have been advocated such as the physiological involution of the pineal gland, a sequestration of the embryonic cavum pineale or the degenerative evolution of glial inclusions within the pineal gland. The pathological description is classical with three layers: an external fibrous capsule, an intermediate layer of pineal tissue and an internal glial wall. Imaging of these lesions is typical, namely the thin rim of peripheral contrast enhancement and the presence of calcifications. These cysts are more frequent in women in their third decade of life. They are almost always latent and their fortuitous disclosure at NMR examinations is common. Some of them will nevertheless cause intracranial hypertension due to hydrocephalus and hemorrhage. Those symptomatic cysts should be treated. Surgical excision has been the method of choice and the results are good. More recently a mere stereotactic needle aspiration has been performed with satisfactory long-term results.

Adult↗
PubMed1995

Differing antibody IgG isotypes in the polar forms of leprosy and cutaneous leishmaniasis characterized by antigen-specific T cell anergy.

Leprosy and American cutaneous leishmaniasis are tropical diseases which present a spectrum of clinical and immunological manifestations. Lepromatous leprosy and diffuse cutaneous leishmaniasis are the severe, progressive polar forms of disease characterized by persistent T cell anergy. Relative concentrations of antibodies belonging to the four IgG isotypes have been determined in these forms of disease as well as active visceral leishmaniasis, which presents transitory T cell anergy. Leishmania-specific IgG4 antibodies predominated in 19/20 sera from patients with diffuse cutaneous leishmaniasis, and IgG1 antibodies predominated in 9/10 cases of untreated visceral leishmaniasis. The predominant IgG isotype of Mycobacterium leprae-specific antibodies in untreated lepromatous leprosy was remarkably variable (IgG1, IgG2, IgG3 and IgG4 in 8, 6, 2 and 1 sera, respectively). Differing IgG antibody isotypes have been associated with distinct CD4+ T cell helper subpopulations and their characteristic lymphokine profiles in several pathologies. These results suggest that T cell anergy in chronic intracellular infections may be associated with as yet undefined mechanisms which modulate reported T helper cell-lymphokine isotype relationships.

Adult↗
PubMed1995

Comparison of Petrifilm method to conventional methods for enumerating aerobic bacteria, coliforms, Escherichia coli and yeasts and molds in foods.

The Petrifilm plates method was compared to conventional methods (PCA, VRBA, Levine EMB agar and OGYE agar) for enumeration of mesophilic aerobic bacteria, coliforms, Escherichia coli, and yeasts+molds in six homogeneous lots of different food groups (pasteurized milk, yoghurt ice cream, eggs, minced meat, fresh strawberries and frozen green beans). For all the microbiological criteria except for yeasts and molds and mesophilic aerobic bacteria in frozen green beans, the mean values of counts with Petrifilm plates were higher than those obtained with traditional methods. The correlation coefficient of Petrifilm aerobic bacteria, coliforms, and yeasts + molds v. PCA, VRBA and OGYE agar for each microbiological criterion for a composite of six food products were 0.897, 0.861 and 0.981, respectively.

Bacteria, Aerobic↗
PubMed1994

A longitudinal study of immunologic reactivity in leprosy patients treated with immunotherapy.

More than 150 leprosy patients treated with multidrug therapy (MDT) plus immunotherapy (IMT) with a mixture of heat-killed Mycobacterium leprae plus live BCG were studied in relation to humoral and cell-mediated immune responses. Many previously had received prolonged sulfone monotherapy. Patients received 2 to 10 doses of IMT in a period of 1 to 3 years, depending upon their clinical form of leprosy. The patients were followed up for 5 to 10 years with repeated determinations of antibody levels to phenolic glycolipid-I; lymphoproliferative (LTT) responses to soluble extract of M. leprae, to whole bacilli and to BCG, skin-test responses and bacterial indexes (BIs). After MDT plus IMT there was a statistically significant decrease of antibody levels in the multibacillary (MB) group. The BI decreased proportionally to the ELISA results. LTT increased to M. leprae antigens, especially to soluble extract, in a high percentage of these patients (34% of LL patients positive). Lepromin positivity in MB patients increased from 5% initially positive to 75% at the cut-off during this follow up. These results show substantial early and persistent cell-mediated reactivity to M. leprae in many MB patients treated with MDT-IMT, confirming and expanding previously published data.

Antibodies, Bacterial↗
PubMed1994

[Treatment of chronic lumbago and radicular pain by spinal cord stimulation. Long-term results].

Seventy-seven patients with chronic, refractory, low back and radicular pain underwent implantation of a spinal cord stimulator between 1984 and 1992. Most patients had failed back surgery syndrome. In every case, an epidural quadripolar "Resume" electrode was implanted surgically. Results were evaluated after three months then after six to 98 months (mean follow-up 42 months). Long-term efficacy was good in 63.6% of cases, fair in 22%, and poor in 6.5%; treatment failure occurred in 7.9% of cases. Adverse events included one case of meningitis, two cases of local infection, and one case each of cerebrospinal fluid fistula and necrosis of the skin overlying the stimulator. The main causes of treatment failure were complications, inappropriate patient selection, and the escape phenomenon. The results of this study demonstrate that spinal cord stimulation is effective for the treatment of chronic low back and radicular pain in carefully selected patients; scrupulous application of restrictive selection criteria is essential to the success of the method.

Adult↗
PubMed1993

Foreign minorities from developing countries in Madrid.

"Spain, which has always been a land of emigrants, is currently a centre of attraction for immigrants, as are other countries in Mediterranean Europe. The proportion is not as high as in other countries with a longer tradition of immigration. In this survey we selected the six nationalities which provide the highest numbers of immigrants from the developing world, and which have the greatest racial or cultural contrast to the native population. We analyse their structural features, whether or not immigrants from the same country...collect in the Madrid Metropolitan Area, the recent mobility of the immigrant population, and the evolution of immigration since the Administration carried out a regularization process, as well as Spaniards' opinion of foreign immigrants."

Attitude↗
PubMed1993

Preparation of activated supports containing low pK amino groups. A new tool for protein immobilization via the carboxyl coupling method.

A method for the preparation of new aminated agarose gels containing monoaminoethyl-N-aminoethyl structures, MANA-agarose gels, has been developed. These gels contain primary amino groups with a very low pK value (6.8). In addition to that, we have been able to prepare very highly activated gels (e.g., 10% agarose gels containing up to 200 mu Eq of primary amines per milliliter). These two properties make these activated supports suitable for performing novel and interesting methods for protein immobilizations via very mild carbodiimide activation of carboxy groups. For example, very effective coupling reactions can be performed at pH 5.0-6.0 in the presence of low concentrations of activating agent, e.g., 1 mM. By using a model industrial enzyme, beta-galactosidase from Aspergillus oryzae, we have been able to demonstrate the excellent prospects of these novel activated supports.

Enzymes, Immobilized↗
PubMed1993

Microbiological quality of French yogurts commercialized in Spain.

The microbiological quality has been evaluated in 6 batches of yogurt (plain, flavoured and fruit-added) produced commercially in France and purchased in Spain. The essential microflora: Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, and contaminants (coliform bacteria, yeasts and molds) were checked. The pH was also measured. The totality of the samples tested fulfilled French and Spanish regulation with respect to the presence of viable yogurt organisms. Likewise, in 100% of the yogurts, counts of contaminants were under 10 cfu/g. The pH ranged between 3.92 and 4.19.

Animals↗
PubMed1993

[Juxta- or trans-condylar lateral extension of the posterior suboccipital approach. Anatomical study, surgical aspects].

In order to improve the surgical approach to tumors and aneurysms of the anterior or antero-lateral aspect of the foramen magnum, some authors have proposed a lateral extension of the posterior sub-occipital approach to the occipital condyle including in some cases its partial or complete resection. The evaluation of this close medio-condylar or trans-condylar suboccipital approach has been performed on eight coloured-latex injected specimens in the conditions of a microsurgical operation. The extra- and intradural steps have been studied so as to define the optimal position of the patient's head and the surgeon and to precise the accessible anatomical structures: Vertebral artery (and its control), Cranial nerves IX, X, XI & XII, Posterior-inferior cerebellar artery and collaterals, Vertebro-basilar junction, antero-lateral aspect of the brain stem and spinal cord. Depending on the extent of the condylar resection, the lateral extension of the posterior sub-occipital approach may be defined as minimal, moderate or large. Based on anatomical and surgical constations it appears that a complete resection of the occipital condyle (resulting in occipito-cervical instability) should be reserved for those very extensive lesions. Yet a partial drilling of the condyle provides a better angle of approach, minimises the hazards of retraction of nervous structures and enables the surgeon to take the best advantage of the dissection and control of the vertebral artery.

Female↗
PubMed1992

[Contribution of ultrasonic cavitation--CO2 laser combination in the excision of panmedullary ependymoma].

The authors report an uncommon case of panmedullary ependymoma (C2 to T12), totally removed in one stage with the use of ultrasonic cavitation and CO2 laser. The preoperative topographical diagnosis without M.R.I. was very difficult. CO2 laser in addition with ultrasonic cavitation allows the removal of the tumor without any prohibitive tractions on the spinal cord. The stable course with a long follow-up period (seven years) confirms the good prognosis of such a pathology.

Adult↗
PubMed1991

Usher syndrome: results of a screening program in Colombia.

Otological, ophthalmological and genetic studies were performed in 46 patients with Usher syndrome, identified through a screening program in Colombia. Of them, 69.6% had Usher syndrome type I, 26.1% type II, and 4.3% type III. Thirty-three patients showed profound deafness (71.7%), while 13 (28.3%) had moderate to severe hearing loss. The ophthalmologic manifestations showed marked variability. Although the majority of the patients had serious ocular impairment before age 20, 32.6% had good central visual acuity. The prevalence of Usher syndrome in Colombia, estimated at 3.2/100,000, warrants the implementation of screening programs in schools for the deaf and for the blind. Our study confirms that Usher syndrome shows no geographic or racial variation and that the disorder has a wide variability of expression and genetic heterogeneity. The large size of the families we have detected may provide important opportunities for further genetic studies, particularly in terms of the assignment of the locus and gene mapping.

Colombia↗
PubMed1990

Differential viral gene expression and its effect on the biological properties of the cell clones of an HIV-1-infected cell line.

We have shown that 6D5 cells infected with the HIV-1 strain HTLV-III451 (6D5(451)) secreted viral envelope proteins gp160 and gp120 into the culture medium. Single cell cloning of 6D5(451) cells separated three distinct phenotypes. All clones secreted unprocessed env protein gp160 along with gp120. Only one phenotype produced infectious virus and contained normally processed gag proteins. The second phenotype was associated with nonproducer cells expressing only the env gene but no extracellular particles. The third phenotype synthesized Pr53gag but no reverse transcriptase, nor did it process the gag precursor. Only immature particles could be seen in the culture. Cells of the first and the third phenotypes produced two sizes of gp160, the normal and one with a small truncation at the C-terminus. Phenotype 2 only produced the smaller gp160. In all cases the gp160 that was secreted into the medium was the truncated molecule.

Capsid↗