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Biomedical subjects

A Navarro

Publications and source records attributed to A Navarro.

At least 73 records · Page 4Linked to original sources
PubMed2001

Anti-inflammatory and immunomodulating properties of a sterol fraction from Sideritis foetens Clem.

A sterol fraction composed of campesterol (7.6%), stigmasterol (28.4%) and beta-sitosterol (61.1%) was obtained by activity-guided fractionation of the acetone extract of Sideritis foetens Clem. This sterol fraction showed anti-inflammatory activity in in vivo murine models of inflammation. It decreased carrageenan paw oedema in mice after oral administration of 30 and 60 mg/kg and inhibited mouse ear oedema induced by 12-O-tetradecanoylphorbol acetate (TPA) after topical application. Quantitation of the neutrophil specific marker myeloperoxidase (MPO) demonstrated that its topical anti-inflammatory activity was associated with reduction in neutrophil infiltration into inflamed tissues. Non-cytotoxic concentrations of the sterol fraction inhibited leukocyte granular enzyme release (beta-glucuronidase) and superoxide generation. However, it did not shown any significant inhibitory effect on histamine release from mast cells. In vitro modulatory activity towards the classical pathway of the complement system shown by this fraction would correlate with the anti-inflammatory profile shown in vivo.

Animals↗
PubMed2001

Neuronal and mixed neuronal glial tumors associated to epilepsy. A heterogeneous and related group of tumours.

The group of brain tumors with mature components encompasses several pathological entities including: the ganglioneuroma; the gangliocytoma; the ganglioglioma; the desmoplastic ganglioglioma; the neurocitoma and a group of glioneuronal hamartomatous tumorous lesions, such as meningoangiomatosis. The dysembryoplastic neuroepithelial tumor is characterized by the presence of multiple cortical nodules made up of small, oligo-like cells and a myxoid pattern rich in mucopolysaccharides. Mature neuronal cells are frequently detected throughout the tumor. Most of them are associated with microhamartias in the adjacent brain and pharmacoresistant epilepsy. The excellent prognosis of the majority of these tumors and the potential for malignant transformation of the glial component in the ganglioglioma are the two most remarkable findings. Histological signs of anaplasia and greater mitotic and proliferative activities are associated with local recurrences. Atypical neurocytomas occur only exceptionally. Treatment choices are surgical resectioning and, in those cases presenting greater proliferative activity and cytological atypia, postoperative radiotherapy may be recommended. This paper reviews this heterogeneous group of neoplasms and hamartomatous lesions, pointing out presumable transitions among the different types of mixed neuronal and glial brain tumors. A single term of "mixed neuronal-glial tumors" is defended, distinguishing different subgroups of tumors, depending on the predominant cellular component.

Adult↗
PubMed2001

The prenatal visit.

In their role as advocates for children and families, pediatricians are in an excellent position to support and guide parents during the prenatal period. Prenatal visits allow the pediatrician to gather basic information from parents, provide information and advice to them, and identify high-risk situations in which parents may need to be referred to appropriate resources for help. In addition, prenatal visits are the first step in establishing a relationship between the pediatrician and parents and help parents develop parenting skills. The prenatal visit may take several possible forms depending on the experience and preferences of the parents, competence and availability of the pediatrician, and provisions of the health care plan.

Adult↗
PubMed2001

Reproducibility and validity of a food-frequency questionnaire in assessing dietary intakes and food habits in epidemiological cancer studies in Argentina.

A Food-Frequency questionnaire (FFQ) is the method chosen for estimating dietary intake in epidemiological studies because it can provide valid and reliable estimates of usual intake in a variety of populations. Colorectal cancer is associated with diet but no information about validity and reproducibility of dietary exposure assessment is available in Argentina. The purpose of the study is to evaluate the validity and reproducibility of the FFQ used in assessing the relationship between dietary intake and colorectal cancer. Selected nutrient intake, measured by two interviewer-administered FFQs, was compared with average intake derived from using four 24 hour dietary recalls (DR) as the reference method, for 62 control subjects from Córdoba, Argentina. Pearson's product-moment and Spearman correlation coefficients were used. Nutrient intakes were adjusted for energy, sex and age using tertiles of residuals from regression models. Weighted and unweighted kappa statistics were calculated for both FFQs versus DR. The mean correlation coefficients between DR and FFQs were 0.74. Agreement measurement (Kappa) varied from 0.51 to 0.74 for FFQ1 vs. FFQ2 to between 0.71 and 0.87 for FFQ1 and FFQ2. This study demonstrates an acceptable validity and reproducibility for this FFQ. The pattern of the correlation coefficients found in the present study indicates that the FFQ can provide an acceptable assessment of long-term dietary intake in the Argentine population and in other Latin-american areas.

Age Factors↗
PubMed2000

Intramolecular

2-Propynyldiarylacetylenes undergo thermal intramolecular [4 + 2] cycloaddition to give benzo[b]fluorene derivatives in good yields. The hybridization of the tether connecting the reacting alkynes has a pronounced effect on the course of the reaction. Theoretical calculations and isotopic labeling studies support a mechanism which involves the generation of a cyclic allene intermediate that evolves to the final benzo[b]fluorene.

Journal Article↗
PubMed2000

Aging and the human vestibular nuclei: morphometric analysis.

The data concerning the effects of age on the brainstem are scarce and few works are devoted to the human vestibular nuclear complex. The study of the effects of aging in the vestibular nuclei could have clinical interest due to the high prevalence of balance control and gait problems in the elderly. We have used in this work eight human brainstems of different ages sectioned and stained by the formaldehyde-thionin technique. The neuron's profiles were drawn with a camera lucida and Abercrombie's method was used to estimate the total number of neurons. The test of Kolmogorov-Smirnov with the correction of Lilliefors was used to evaluate the fit of our data to a normal distribution and a regression analysis was done to determine if the variation of our data with age was statistically significant. Aging does not affect the volume or length of the vestibular nuclear complex. Our results clearly show that neuronal loss occurs with aging in the descending (DVN), medial (MVN), and lateral (LVN) vestibular nuclei, but not in the superior (SVN). There are changes in the proportions of neurons of different sizes but they are not statistically significant. The neuronal loss could be related with the problems that elderly people have to compensate unilateral vestibular lesions and the alterations of the vestibulospinal reflexes. The preservation of SVN neurons can explain why vestibulo-ocular reflexes are compensated after unilateral vestibular injuries.

Adult↗
PubMed2000

MEFV mutations in Behçet's disease.

Familial Mediterranean fever (FMF) and Behçet's disease (BD), both inflammatory diseases, are highly prevalent in the Middle Eastern and Mediterranean populations. FMF is a Mendelian autosomic recessive disease linked to MEFV, a gene of unknown function. BD in contrast is a polyfactorial disease associated with the major histocompatibility complex. Because FMF and BD have epidemiological similarities, we asked whether the FMF gene was implicated in BD. We screened for the common MEFV mutations a cohort of 114 chromosomes from definite BD patients [meeting the criteria of the International study group] and probable cases [meeting at least two of these criteria]. We screened in parallel an ethnically matched cohort of FMF and control chromosomes. The M694V, V726A and E148Q mutations tended to be more frequent in definite BD (2.6%, 2.6%, and 5.2%, respectively) than in controls (0%, 0%, and 2.2%). The P706 polymorphism was found in 10.5% of the probable BD chromosomes, but in only 1.6% of the controls (p=0.01). Because some MEFV mutations were more frequent in BD than in controls, we suggest that they may act as additional susceptibility factors in BD.

Africa, Northern↗
PubMed2000

Normothermic recirculation reduces primary graft dysfunction of kidneys obtained from non-heart-beating donors.

Our aim was to analyze the short- and long-term function of kidneys procured from non- heartbeating donors (NHBD) by means of three techniques: in situ perfusion (ISP), total body cooling (TBC) and normothermic recirculation (NR). Fifty-seven potential NHBD were included. Mean warm ischemia time was 68.9 +/- 35.6 min. Forty-four kidneys were obtained from donors perfused with ISP, 8 with TBC, and 8 with NR. Eighteen kidneys (32%) started functioning immediately, 29 (52%) showed delayed graft function (DGF) and 9 (16%) showed primary non function (PNF). The actuarial graft survival rate was 76.4% at 1 year and 56% at 5 years. The patient survival rate was 89.3% at 5 years. Incidence of DGF and PNF was significantly lower in kidneys perfused with NR than those with ISP or TBC (P < 0.01). Duration of DGF was shorter in kidneys obtained through TBC than in kidneys obtained with ISP (P < 0.05). In conclusion, NR reduces the incidence of DGF and may be considered the method of choice for kidney procurement from NHBD.

Adult↗
PubMed2000

Experimental and theoretical vibrational study of silyl trifluoromethanesulfonate, CF3SO2OSiH3.

Infrared and Raman spectra were obtained for liquid silyl trifluoromethanesulfonate, a silylating agent of limited stability. The molecular geometry was optimized by means of density functional theory and Möller-Plesset second order perturbation theory methods, using different basis sets. The optimized structure presents a gauche conformation, similar to that adopted by methyl trifluoromethanesulfonate, which was determined experimentally a short time ago. The wavenumbers for the normal modes of vibration and the corresponding force constants were also calculated, facilitating the interpretation of the vibrational data. The harmonic force constants given by theory were scaled to reproduce adequately the experimental wavenumbers.

Models, Chemical↗
PubMed2000

Successful treatment of aphthous ulcerations in AIDS patients using topical granulocyte-macrophage colony-stimulating factor.

Oral recurrent aphthous ulceration (RAU) is a well-recognized complication in patients infected with human immunodeficiency virus. RAU can be progressive and destructive, causing dysphagia and secondary malnutrition. The aetiology of RAU remains unknown, and its response to available treatments is often unsatisfactory. We describe three patients with advanced AIDS who suffered from extensive RAU which failed to respond to several treatments, including topical viscous lidocaine and topical and systemic glucocorticoids. Owing to difficulties in using thalidomide (two patients had neurological conditions which precluded thalidomide use), all three patients were treated with an oral solution containing recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF, 400 microg in 5% glucose 200 mL). From the first application, all three patients showed significant improvement of their lesions and amelioration of pain, and they were completely cured in a few days. No adverse effects were recorded. The patients did not show relapses of RAU over a prolonged follow-up. Controlled trials are warranted in order to establish the role of GM-CSF as a valid, alternative option for aphthous ulcerations of the mouth in AIDS patients in whom corticosteroids or thalidomide are not suitable.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Dorsolateral biplane closing radial osteotomy in zero variant cases of Kienböck's disease.

Twenty-six patients with Lichtman stages II and III Kienböck's disease had biplane dorsolateral radial closing osteotomy to reduce the radial inclination and dorsal angles on the sagittal plane. The effects of the procedure were studied clinically, radiologically, and by magnetic resonance imaging in a 2- to 6-year follow-up study (average follow-up period, 3.5 years). The signal intensity on T1- and T2-weighted images of the lunate increased after surgery in all patients, suggesting revascularization. The comparative advantages of this technique are discussed with regard to others currently used.

Adolescent↗
PubMed2000

Immunomodulating properties of the diterpene andalusol.

Andalusol [ent-13(16),14-labdadiene-6 alpha,8 alpha,18-triol], a labdane diterpene isolated from an anti-inflammatory extract of the medicinal plant Sideritis foetens Clem. was evaluated for immunomodulating properties. It exhibited a dose-dependent inhibitory effect on the hemolytic activity of the classical complement pathway and also inhibited lymphocyte proliferation induced by concanavalin A at non-cytotoxic concentrations (1-100 microM). No effect on the alternative pathway was observed. These results indicate that andalusol has immunosuppressive effects in vitro in addition to its anti-inflammatory activity.

Adjuvants, Immunologic↗
PubMed2000

Effect of inversion polymorphism on the neutral nucleotide variability of linked chromosomal regions in Drosophila.

Recombination is a main factor determining nucleotide variability in different regions of the genome. Chromosomal inversions, which are ubiquitous in the genus Drosophila, are known to reduce and redistribute recombination, and thus their specific effect on nucleotide variation may be of major importance as an explanatory factor for levels of DNA variation. Here, we use the coalescent approach to study this effect. First, we develop analytical expressions to predict nucleotide variability in old inversion polymorphisms that have reached mutation-drift-flux equilibrium. The effects on nucleotide variability of a new arrangement appearing in the population and reaching a stable polymorphism are then studied by computer simulation. We show that inversions modulate nucleotide variability in a complex way. The establishment of an inversion polymorphism involves a partial selective sweep that eliminates part of the variability in the population. This is followed by a slow convergence to the equilibrium values. During this convergence, regions close to the breakpoints exhibit much lower variability than central regions. However, at equilibrium, regions close to the breakpoints have higher levels of variability and differentiation between arrangements than regions in the middle of the inverted segment. The implications of these findings for overall variability levels during the evolution of Drosophila species are discussed.

Animals↗
PubMed2000

The human Y chromosome genes BPY2, CDY1 and DAZ are not essential for sustained fertility.

Deletions of the AZFc interval of the human Y chromosome are found in >5% of male patients with idiopathic infertility and are associated with a severely reduced sperm count. The most common deletion type is large (>1 Mb) and removes members of the Y-borne testis-specific gene families of BPY2, CDY1, DAZ, PRY, RBMY2 and TTY2, which are candidate AZF genes. Four exceptional individuals who have transmitted a large AZFc deletion naturally to their infertile sons have, however, been described. In three cases, transmission was to an only son, but in the fourth case a Y chromosome, shown to be deleted for all copies of DAZ, was transmitted from a father to his four infertile sons. Here we present a second family of this latter type and demonstrate that an AZFc-deleted Y chromosome lacking not only DAZ, but also BPY2 and CDY1, has been transmitted from a father to his three infertile sons. Polymerase chain reaction (PCR) and Southern blot analyses revealed no difference in the size of the AZFc deletion in the father and his sons. We propose that the father carries rare alleles of autosomal or X-linked loci which suppress the infertility that is frequently associated with the absence of AZFc.

Adult↗
PubMed2000

[Profile of occupational disease outpatients and the presence of repetitive strain injury].

OBJECTIVE: To assess the profile of outpatients seen at an occupational disease clinic of a general and repetitive strain injury (RSI) patients by using multivariate analyze. METHODS: The first 565 visit registries for the year 1996 were assessed regarding their social and demographics aspects, work characteristics, and diagnosis. All the variables were analyzed by univariate analysis method. Bivariate data were analyzed using Chi square test (chi2) for categorical variables, comparison of means or ranges for quantitative and categorical variables. Multivariate data were analyzed using log-linear models with logit-transformation to identify the groups with a larger proportion of RSI. RESULTS: Women sought the occupational diseases clinic more frequently than men, and there was a predominance of RSI cases. The occupation distribution was in order of priority as following: office workers, factory workers, and service workers. Of them, 56.9% were from the economic sector of services. RSI was seen in 56% of the patients diagnosed at their first visit. CONCLUSIONS: The analysis confirms the trends seen in the 80s regarding the epidemiological changes in occupational diseases, when RSI started to be identified and displaced to a secondary position the other common diseases (due to physical and chemical hazards) because of inadequacy of ergonomics.

Adult↗