Publications by authors named "Navarrete M"

Novel devices consisting of uniform-waist tapered optical fibers with asymmetric double-layer (metal plus dielectric) depositions have been recently proposed as refractive-index sensors. We study the properties of light transmission by use of this kind of devices, and we specifically perform a detailed study of the generation of surface-plasma waves in the structures. We show that multiple surface plasmons are excited for specific combinations of the constructive parameters of the devices and for specific ranges of the refractive index of the surrounding medium.

View Article and Find Full Text PDF

Our study was designed to contribute to an understanding of the timing and conditions under which transmission of Andes hantavirus in Oligoryzomys longicaudatus reservoir populations takes place. Mice were caged in test habitats consisting of steel drums containing holding cages, where seronegative rodents were exposed to wild seropositive individuals by freely sharing the same cage or being separated by a wire mesh. Tests were also performed for potential viral transmission to mice from excrement-tainted bedding in the cages.

View Article and Find Full Text PDF

The Polycomb group (PcG) of proteins comprises a family of repressors of homeobox genes that play key roles in body formation, haematopoiesis and cell cycle control. In this study, a large-scale analysis of PcG protein expression (BMI1, MEL18, PH1, RNF2, RING1, and RYBP) was performed in 321 Hodgkin's lymphoma (HL) biopsies and in reactive lymphoid tissues using tissue microarrays. The relevance of PcG proteins in HL was also investigated by the simultaneous analysis of PcG and other proteins involved in the control of cell cycle, transcription machinery and lymphoid differentiation.

View Article and Find Full Text PDF

This paper presents the results obtained for thoron concentration in 50 single-family dwellings in normal occupancy conditions (open house conditions), measured by a passive electret system (type E-PERM, SSTB configuration) in a 2001-2002 monitoring survey in the Metropolitan Zone of Mexico City. The results show the general log-normal distribution of integrated indoor thoron concentration with annual arithmetic and geometric means of 82 and 55 Bq m(-3), respectively, with ranges from 8 to 234 Bq m(-3) higher than world average of 3 Bq m(-3). The seasonal variation shows the minimum mean values in the summer season that were 35% lower than in autumn.

View Article and Find Full Text PDF

A computational approach to calculating potential energy surfaces for reactive systems is presented and tested. This hybrid approach is based on integrated methods where calculations for a small model system are performed by using analytical potential energy surfaces, and for the real system by using molecular orbital or molecular mechanics methods. The method is tested on a hydrogen abstraction reaction by using the variational transition-state theory with multidimensional tunneling corrections.

View Article and Find Full Text PDF

The development of a program to produce 131I by neutron activation of previously sintered TeO2, was started at the Nuclear Center of Mexico 3 y ago. Since then, the problems related to producing high purity, sintered TeO2 for neutron activation, transport of the activated samples and melting of the samples to retrieve the 131I have been satisfactorily solved. The main problems, related to health physics, arise when the process is conducted on a daily basis.

View Article and Find Full Text PDF

A novel, to our knowledge, device based on a tapered optical fiber with a double-layer deposition including a metallic media is presented, and its properties are studied. The main novelty of the device consists of the introduction of a dielectric layer, whereas the systems depicted in the literature are simply metal-coated tapered fibers. The presence of the dielectric layer permits one to tune the response of the device to the refractive index of the surrounding medium.

View Article and Find Full Text PDF

Background: Countries with scarce resources have the right to appropriate essential health care but very few reports discuss how this can be achieved. We assessed the survival of a large cohort of pediatric oncological patients to provide hard data on which to base realistic evaluation and planning schemes.

Patients And Methods: This multicenter retrospective survey covered consecutively diagnosed and treated patients admitted to eight national level hospitals in seven countries in Central America and the Caribbean.

View Article and Find Full Text PDF

Objective: To present an analysis of our experience with 22 consecutive cases of acute abdominal gynecologic emergencies managed with a laparoscopic approach.

Methods: From March 1997 to October 1998, 22 patients with a diagnosis of acute abdominal gynecologic emergencies underwent laparoscopic intervention. A transvaginal ultrasound was performed on all patients preoperatively to supplement the diagnostic workup.

View Article and Find Full Text PDF

Genotype polymorphism studies at the 13 loci STRs included in the combined DNA index system [CODIS and PCR-based short tandem repeat loci, in: Proceedings of the Second European Symposium on Human Identification, Promega Corporation, Madison, WI, 1998, pp. 73-88; J. Forensic Sci.

View Article and Find Full Text PDF

Patients with systemic lupus erythematosus (SLE) often show cognitive impairment on traditional neuropsychological tests; however, many of these tests are unsuitable for use with mixed ethnic populations. Computer-administered cognitive tests are promising, but have not been validated against traditional tests or with predominantly Hispanic samples. We gave 67 lupus patients a computer-administered test battery (Automated Neuropsychological Assessment Metrics--ANAM) and a battery of traditional neuropsychological tests.

View Article and Find Full Text PDF

DNA damage was induced by either 2 mM ethylmethanesulfonate or 1 Gy of gamma-irradiation in Allium cepa L. root meristems. The percentage of DNA that migrated towards the anode during microelectrophoresis after alkali denaturation (pH approximately 13.

View Article and Find Full Text PDF

Background: In Chile, three Hantavirus seropositive rodent species (O longicaudatus, A olivaceus and A longipilis) are distributed from the Pacific coast to the Andes mountains and represent nearly 90% of the rodents captured in the Xth Region.

Aim: To study the seroprevalence of Hantavirus among captured rodent species and its relationship with the appearance of human cases of pulmonary syndrome.

Material And Methods: From May 1998 to September 2001, 675 rodents were captured in the region.

View Article and Find Full Text PDF

Background: Social participation in the health system constitutes one of the basic principles of Brazilian health sector reform. This paper analyses the concepts held by different groups of stakeholders with respect to social participation in health and identifies their opinions on hindering and enabling factors for this participation.

Methods: A qualitative study was conducted using individual interviews (II) and focus groups (FG) with different groups of stakeholders: 135 users (II, GF), 14 community leaders (II, GF), 12 Municipal Health Council (MHC) members (II), 8 policymakers and (II) 37 health personnel (II, GF) were interviewed.

View Article and Find Full Text PDF

Objective: The San Antonio Lupus Study of Neuropsychiatric Disease is a longitudinal study designed to characterize the spectrum of and important risk factors for specific neuropsychiatric systemic lupus erythematosus (NPSLE) syndromes.

Methods: Subjects must meet criteria for SLE and must be at least 18 years of age. A standardized medical history, neurologic, rheumatologic, and psychiatric examinations, computerized neuropsychological evaluation, and serologic testing are performed.

View Article and Find Full Text PDF

We determined the nuclear volume of fibroblasts of the normal mammary lobular stroma during the follicular and luteal phases of the menstrual cycle. Twenty patients aged 15 to 35 years and eumenorrheic for at least 6 months were randomly assigned to 2 groups, i.e.

View Article and Find Full Text PDF

The seroprevalence of Chlamydia pneumoniae and Mycoplasma pneumoniae in hantavirus seronegative patients, who had symptoms and signs compatible with pneumonia was established. For this purpose we used the indirect fluorescent antibody test. Titers > or = 1:16 for C.

View Article and Find Full Text PDF

Recurrent facial palsy is noted infrequently in the literature. We present a comparative study of recurrent Bell's palsy (RBP) with regard to non-recurrent Bell's palsy (NRBP). Afterwards we compare among RBP cases those of ipsilateral recurrence (RRBP) to those of contralateral one (ARBP).

View Article and Find Full Text PDF

The description of primary cutaneous follicular lymphoma has raised interest in the differential diagnosis of this versus disseminated follicular lymphoma involving the skin. We report here on four cases of Stage IV follicular lymphoma, diagnosed in skin biopsy, in which cutaneous lesion was the most noticeable feature of clinical presentation. In all cases, the morphological features were superimposed over typical nodal follicular lymphoma.

View Article and Find Full Text PDF

Background And Objectives: Bone marrow biopsies are routinely performed in the staging of patients with lymphoma. Despite the lack of evidence for its usefulness, many institutions include flow cytometry (FC) of bone-marrow aspirates in an attempt to increase sensitivity and specificity. The aim of this study is to evaluate the usefulness of FC for the assessment of bone-marrow involvement by lymphoma in follicular (FL) and diffuse large B-cell lymphomas (DLBCL).

View Article and Find Full Text PDF

The HIV virus induces in the host several changes in your immunological system, which heads to the AIDS. We report two cases diagnosed by pathological studies after adenotonsilectomy for adenotonsilar hypertrophy. The diagnosis of HIV patients is suspected by epidemiologic (risk groups) or clinical features (opportunist diseases).

View Article and Find Full Text PDF

There is a checkpoint pathway in eukaryotic cells that depends on ATM (ataxia telangiectasia mutated) kinase which activates the processes leading to the repair of DNA damage and also lengthens the G(2) stage of the cell cycle. In cells from ataxia telangiectasia patients, due to their lack of active ATM kinase, an increase in chromosomal aberrations and a failure to induce G(2) lengthening could be expected. However, the basal G(2) timing in ataxia telangiectasia cells was longer than in controls and was further extended after X-ray irradiation (0.

View Article and Find Full Text PDF

The lack of precise and homogeneous criteria for the recognition of primary cutaneous follicular lymphoma has hindered gaining data on the frequency and clinical and molecular features of this entity. In the course of a review of a series of primary cutaneous lymphoma from different Spanish hospitals, we collected a series of 18 cases of primary cutaneous follicular lymphoma and analyzed its clinical, morphologic, and biologic characteristics. In this review only cases with a follicular pattern of growth, germinal center cytology, and restriction to the skin in a minimum follow-up of 6 months have been included.

View Article and Find Full Text PDF

A cytogenetic and/or cytochemical study was performed in 166 individuals with leukemia or related disorders, in two major Costa Rican hospitals. In those patients treated at an adult's hospital (14 years old and over), acute leukemias represented 66% of all cases. In that hospital the most frequent types of disorders were, in decreasing order: ANLL (> M1), ALL, CML (all of them showed the Ph chromosome) and MDS.

View Article and Find Full Text PDF