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Biomedical subjects

E Mendoza

Publications and source records attributed to E Mendoza.

At least 19 recordsLinked to original sources
PubMed2006

[VOT analysis in cleft palate patients after surgery].

OBJECTIVES: To determine the factors that modify the measures of voice onset time (VOT) as acoustic parameter in operated cleft palate children. The voice of cleft palate patient is defined by the generation of an abnormal intraoral pression. This doesn't allow the normal generation of voiceless plosives consonants and produces an increased VOT. Acoustic analysis of voice quantifies these parameters. In this study we observed an increased VOT if the patient hadn't got a normal teeth occlusion and a normal soft palate function. Also VOT measures were influenced by cleft lip and delay in beginning of ortodoncy. Hearing loss is associated with increased VOT. Our results are based in a correct sample and statistical analysis by multiple lineal regression.

Adolescent↗
PubMed2005

Phenotypic and transcriptional characterization of the meningococcal PhoPQ system, a magnesium-sensing two-component regulatory system that controls genes involved in remodeling the meningococcal cell surface.

We previously identified and characterized a two-component regulatory system in the meningococcus with homology to the phoP-phoQ system in salmonella and showed that allele replacement of the NMB0595 regulator gene led to loss of virulence, sensitivity to antimicrobial peptides, perturbed protein expression, and magnesium-sensitive growth. On the basis of these findings we proposed that the system should be designated the meningococcal PhoPQ system. Here we further characterized the NMB0595 mutant and demonstrated that it had increased membrane permeability and was unable to form colonies on solid media with low magnesium concentrations, features that are consistent with disruption of PhoPQ-mediated modifications to the lipooligosaccharide structure. We examined the transcriptional profiles of wild-type and NMB0595 mutant strains and found that magnesium-regulated changes in gene expression are completely abrogated in the mutant, indicating that, similar to the salmonella PhoPQ system, the meningococcal PhoPQ system is regulated by magnesium. Transcriptional profiling of the mutant indicated that, also similar to the salmonella PhoPQ system, the meningococcal system is involved in control of virulence and remodeling of the bacterial cell surface in response to the host environment. The results are consistent with the hypothesis that the PhoP homologue plays a role in the meningococcus similar to the role played by PhoP in salmonella. Elucidating the role that the PhoPQ system and PhoPQ-regulated genes play in the response of the meningococcus to the host environment may provide new insights into the pathogenic process.

Bacterial Proteins↗
PubMed2004

Segmental hypoplasia of the great saphenous vein and varicose disease.

OBJECTIVES: Primitive narrowing of great saphenous vein segments (saphenous hypoplasia) has been described in healthy limbs. The aim of the present study was to detect great saphenous vein segmental hypoplasia in limbs with varicose veins and to evaluate the local anatomical and haemodynamic patterns. MATERIALS AND METHODS: The incidence of saphenous hypoplasia and the local haemodynamic rearrangement were evaluated by duplex ultrasonography in 676 normal limbs and in 320 limbs with varicose veins. RESULTS: Segmental hypoplasia was demonstrated in 84 normal limbs and in 79 limbs with saphenous reflux. In the latter, the retrograde flow leaves the GSV at the proximal end of the hypoplastic segment to feed tributary veins. CONCLUSIONS: Saphenous hypoplasia occurs in varicose limbs more frequently than in healthy ones (p= >0.001). It greatly influences the path of the reflux and the anatomy of the varicose veins. GSV segmental hypoplasia can be detected preoperatively by duplex ultrasonography. Its occurrence may influence surgical management for two main reasons: in about 68% of varicose limbs with segmental hypoplasia, the distal GSV is competent. If the distal GSV is varicose, its size and flow direction is normalised by treating the accessory vein that bypasses the hypoplastic segment.

Adolescent↗
PubMed2002

Immune response, nitric oxide, autonomic dysfunction and stroke: a puzzling linkage on Trypanosoma cruzi infection.

Trypanosoma cruzi (T. cruzi) is a tissue parasite causing American trypanosomiasis or Chagas' disease (ChD) affecting, mostly, the cardiovascular and gastrointestinal systems. We have recently found that people infected by T. cruzi are also more prone to developing ischemic strokes than the general population, even without heart complications; the pathomechanism of it is not yet well understood. However, after infection occurs, immune response induces endothelial dysfunction due to an endothelial nitric oxide synthase (eNOS) inhibition and increased activity of inducible nitric oxide synthase (iNOS). These factors are active in inducing vasoconstriction and cerebral microvascular spasms, leading to ischemic stroke. In addition, patients with ChD, regardless of cardiopathy, also have autonomic dysfunction, all of which may enhance the risk of developing ischemic stroke. Moreover, the possibility that these neuroimmunomodulatory pathways are disturbed in patients with other types of stroke seems possible, and is worthy of investigation.

Animals↗
PubMed2002

Perceptual analysis in different voice samples: agreement and reliability.

The objective of this study was to estimate the agreement and reliability of voice evaluation by a group of expert listeners using the central portion of a sustained vowel and a fragment of connected speech as voice samples. Ratings were made using Wilson's Buffalo III Voice Screening Profile. Analysis showed that intraindividual listeners' agreement presented variability in the evaluation of both voice samples. In the evaluation of the central portion of the sustained vowel, interindividual listener agreement was moderate for breathiness, hyponasal resonance, and overall voice rating; in connected speech, agreement was moderate for most voice qualities (breathy, rough, high/low pitch, and hyponasal resonance). Finally, Wilson's Buffalo III Voice Screening Profile presented good reliability values for both voice samples, with overall voice rating achieving higher values (.90) than any other voice-quality variable.

Adult↗
PubMed2001

High-affinity inhibition of glutamate release from corticostriatal synapses by omega-agatoxin TK.

To know which Ca(2+) channel type is the most important for neurotransmitter release at corticostriatal synapses of the rat, we tested Ca(2+) channel antagonists on the paired pulse ratio. omega-Agatoxin TK was the most effective Ca(2+) channel antagonist (IC(50)=127 nM; maximal effect=211% (with >1 microM) and Hill coefficient=1.2), suggesting a single site of action and a Q-type channel profile. Corresponding parameters for Cd(2+) were 13 microM, 178% and 1.2. The block of L-type Ca(2+) channels had little impact on transmission, but we also tested facilitation of L-type Ca(2+) channels. The L-type Ca(2+) channel agonist, s-(-)-1,4 dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)phenyl]-3-pyridine carboxylic acid methyl ester (Bay K 8644 (5 microM)), produced a 45% reduction of the paired pulse ratio, suggesting that even if L-type channels do not participate in the release process, they may participate in its modulation.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2001

[Rheumatic diseases in adolescence]

OBJECTIVE: To present an updated review concerning the most prevalent diseases with musculoskeletal signs and symptoms that make adolescents seek medical care, giving special emphasis to rheumatic diseases. Our aim is to offer physicians and health care providers the possibility of distinct differential diagnoses, thus allowing them to establish a therapeutic approach and, if necessary, refer the patient to a specialist METHODS: Review of literature using Medline database, data obtained at our department, and the authorś personal experience. RESULTS: Musculoskeletal pain is characteristic of several diseases and usually urges adolescents to seek medical care. Rheumatic diseases, especially rheumatic fever, account for nearly fifty percent of the cases. In adolescents, it is also important that the aspects regarding the diagnosis and treatment of idiopathic juvenile arthritis, arthritis associated with enthesitis, systemic lupus erythematosus, and vasculitis be considered. Fibromyalgia, reflex sympathetic dystrophy, growing pains, hypermobility syndrome, and psychogenic rheumatism are noninflammatory conditions that frequently mimic rheumatic diseases. CONCLUSIONS: Inflammatory and noninflammatory conditions, and diseases of different etiology (infectious, neoplastic, and orthopedic) are frequently associated with musculoskeletal pain. It is important that health professionals diagnose these diseases as early as possible so that prompt action can be taken and prognosis can be improved.

Journal Article↗
PubMed1999

Vocal tremor and psychological stress.

This study examines vocal tremor and its decrease in high versus low experimentally induced stress situations. We have analyzed the Amplitude Tremor Intensity Index (ATRI) and Frequency Tremor Intensity Index (FTRI) from the prolongation of vowel /a/ for approximately 5 seconds, under baseline conditions and under 3 different test conditions (reading of tongue twister, reading of tongue twister with delayed auditory feedback [DAF], and spelling of alphabet in reverse order), in a 2-test series, with and without demanding experimental instructions (Experiments 1 and 2, respectively). Inclusion of experimental instructions was considered as making the first test situation more stressful than the second one. Our results show a significant decrease in the ATRI variable when reading a tongue twister with DAF in relation to the baseline for the first test but not in the second, which suggests a suppression or significant reduction of amplitude tremor only in high-stress situations.

Adolescent↗
PubMed1999

Prolonged low-dose infusion of human parathyroid hormone does not increase femoral cancellous bone volume in ovariectomized rats.

OBJECTIVE: Daily injections of human parathyroid hormone (hPTH) increase bone volume in various animal species and in osteoporotic women. For hPTH to be widely accepted as an anabolic therapy for treating postmenopausal osteoporosis alternative delivery options need to be explored to replace the need for daily patient subcutaneous self-injection. Among these are inhalation, oral delivery and the use of programmable implanted minipumps to deliver the peptide. While infusion of high doses of PTH causes bone loss and hypercalcemia, no studies have assessed the effects of prolonged infusion of low doses of PTH on bone growth. DESIGN AND METHODS: [Leu(27)]-cyclo(Glu(22)-Lys(26))-hPTH-(1--31)NH(2) was delivered by Alzet minipumps to ovariectomized rats for 6 weeks after which histomorphometric indices (cancellous bone volume, trabecular thickness, mean trabecular number) of bone formation were measured in distal femurs. RESULTS: Infusing low doses (0.05 and 0.1 nmole/100g body weight/day) of the hPTH analog, [Leu(27)]-cyclo(Glu(22)-Lys(26))-hPTH-(1--31)NH(2), for 6 weeks does not prevent the ovariectomy-induced loss of rat femoral cancellous bone volume, trabecular thickness or trabecular number. CONCLUSION: These results support the absolute requirement of daily injections for the osteogenic action of hPTH on bone.

Animals↗
PubMed1999

Intoxication in cattle from Cestrum diurnum.

Twenty-six Holstein calves with clinical and pathological effects suggesting a toxic plant intoxication were studied. A view of the plants in the region and blood examination (hemogram, albumin, total protein, calcium and phosphorus) and determination of bone calcium were done. Five calves were slaughtered and pathological examinations were performed. Observed metabolic, pathological and clinical alterations were compatible with intoxication from Cestrum diurnum.

Animals↗
PubMed1998

Acoustic analysis of induced vocal stress by means of cognitive workload tasks.

The purpose of this study was to determine the acoustic effects on voice of three tasks of cognitive workload and their possible relationship to stress. Acoustic analysis was used to measure stress and workload in four experimental tasks and two experiments. In the first experiment, subjects performed cognitive workload tasks under a stressful condition, performing the tasks as rapidly as possible without errors and with the knowledge that any errors committed would reduce their grade in a course. The second condition was to perform the same tasks but without the condition of stress related to the final grade. Four testing conditions were included. One was a baseline measure in which subjects spelled the Spanish alphabet. The second was the reading of a tongue twister, the third was the reading of a tongue twister with delayed auditory feedback, and the fourth was spelling the Spanish alphabet in reverse order. In each condition the subjects prolonged the vowel /a/ for, approximately 5 sec. All subjects performed a test to determine their overall level of anxiety. The results suggest that in conditions of experimentally induced stress there is an increase in the fundamental frequency (F0) relative to baseline, an increase in jitter and shimmer, an increase in the high-frequency harmonic energy, and a decrease in spectral noise.

Adolescent↗
PubMed1998

Phase II study of intravenous adenosine 5'-triphosphate in patients with previously untreated stage IIIB and stage IV non-small cell lung cancer.

Fifteen patients with Stage IIIB or IV non-small cell lung cancer gave informed consent to receive three or more 96-hour infusions of ATP at a dose of 50 mcg/kg/min or higher to determine whether ATP has antineoplastic activity against this tumor type and to better define the spectrum of toxicity for ATP given as a single agent. There were no objective complete or partial responses observed. The median survival of the overall group was 187 days and the median time to tumor progression was 113 days. The major toxic side effects were chest pain and dyspnea, leading to the cessation of treatment in 5 patients. We conclude that ATP at this dose and schedule of administration is an inactive agent in patients with advanced non-small cell lung cancer.

Adenosine Triphosphate↗
PubMed1997

Interobserver agreement of perceived intelligibility of magnitude of r in children.

This study was designed to test whether independent listeners could correctly classify 162 stimuli (words) that started with a multiple trill, magnitude of r, followed by a vowel magnitude of a. The sounds were from 27 Spanish children between the ages of 3.0 and 6.6 years, pronouncing Spanish words current in their vocabulary. Twelve listeners were presented with the recordings of the children's magnitude of r production and were instructed to rate the intelligibility of the pronounced sound as high, medium, or low. Inter-rater agreement ranged from 85 to 96%. Analyses of variance for each of the three production categories showed that there were significant differences, so it seems possible to classify the words starting with a trilled magnitude of r based on auditory-perceptual features into three broad categories according to intelligibility.

Child↗
PubMed1996

Differences in voice quality between men and women: use of the long-term average spectrum (LTAS).

The goal of this study was to determine if there are acoustical differences between male and female voices, and if there are, where exactly do these differences lie. Extended speech samples were used. The recorded readings of a text by 31 women and by 24 men were analyzed by means of the Long-Term Spectrum (LTAS), extracting the amplitude values (in decibels) at intervals of 160 Hz over a range of 8 KHz. The results showed a significant difference between genders, as well as an interaction of gender and frequency level. The female voice showed greater levels of aspiration noise, located in the spectral regions corresponding to the third formant, which causes the female voice to have a more "breathy" quality than the male voice. The lower spectral tilt in the women's voices is another consequence of this presence of greater aspiration noise.

Adult↗
PubMed1996

The long-term average spectrum as a measure of voice stability.

This paper aims at providing a methodological answer to the topic of voice stability. Seventeen experimental subjects read a standard text 5 times during a 2-week period. The data were obtained through the Long-Term Average Spectrum and were analyzed with a twofold procedure: (i) analysis of the absolute energy values at different frequency points throughout the length of the spectrum, and (ii) analysis of the relative values obtained by subtraction of each of two consecutive frequency values analyzed. The results obtained with the first procedure indicate that the differences that exist between the various sessions are centered mainly in the frequencies below 0.6 kHz and in the area of 4 kHz, following a linear tendency. The fact that the differences between sessions disappear when employing relative measures may indicate that the utilization of these measures eliminates the sources of systematic or aleatoric error can be introduced during a recording or in the period of time between two consecutive recording sessions.

Adult↗
PubMed1996

Serological reactivity to a synthetic analog of phenolic glycolipid I and early detection of leprosy in an area of low endemicity.

A total of 23,863 individuals living in an area of low endemicity for leprosy were tested by enzyme-linked immunosorbent assay with a semisynthetic analogue of the phenolic glycolipid I antigen of Mycobacterium leprae. The proportion found positive was 3.86% which was significantly higher than that in a sample of a population known to be free of leprosy. Clinical examinations as well as Mitsuda and skin smear tests were organized for those defined as seropositive. The proportion of individuals with lepromin reactions of less than 3 mm increased 18.9% per serological interval as antibodies rose though it was not statistically significant. As a result of the clinical and bacteriological examinations, 2 cases with clinical signs and heavy bacillary load were found, whereas acid-fast bacilli were demonstrated in 2 other individuals without clinical manifestations of leprosy. The usefulness of the system for control purposes is discussed.

Adolescent↗