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Biomedical subjects

G Plaza

Publications and source records attributed to G Plaza.

At least 19 recordsLinked to original sources
PubMed2006

Tinnitus and Ménière's disease: characteristics and prognosis in a tinnitus clinic sample.

The aim of this study is to describe tinnitus epidemiological characteristics in Ménière's disease (MD), the prognosis and its interaction with other MD symptoms. It is a descriptive transversal study. One hundred two MD patients were referred to a tinnitus clinic. Tinnitus was evaluated according to psychoacoustical tinnitogram, visual analogue scale, and tinnitus handicap inventory (THI). All patients were diagnosed with definitive MD (following AAO-HNS' 95 criteria). Pitch was more commonly identified in low and medium frequencies. Psychoacoustical intensity was matched in 12.7 dB. The visual analogue scale showed a value of 7.1, while THI score reached an average of 49%. Compared with other aetiologies (acoustic trauma, otosclerosis), MD showed a statistical difference in tinnitus severity parameters (P<0.05). Tinnitus increased VAS and THI score as a function of duration and bilateral disease (P<0.01). We found a statistical association (P<0.05) between tinnitus intensity and worse hearing loss or hyperacusis, but it was not influenced by number of vertigo spells. Higher MD stage increased tinnitus intensity and handicap. Tinnitus in MD patients referred to our tinnitus clinic presents a high intensity and handicap levels and represents the most troublesome symptom. Severity is influenced by the longer duration of the disease, the bilateral affection, hearing impairment or hyperacusis and a higher MD stage.

Adolescent↗
PubMed2006

Sinonasal fibrosarcoma: a case report.

Sinonasal fibrosarcoma (SFS) is an infrequent malignant neoplasm. It usually presents as other sarcomas in this region, with nasal obstruction and epistaxis. The final diagnosis is based on the histopathology and immunohistochemistry. We report the case of a 58-year-old man with an 8-month history of left proptosis, recurrent epistaxis and nasal obstruction. Nasal endoscopy confirmed a left nasal neoplasia. CT and MRI showed the extension of the neoplasia, occupying the left nasal fossa and ethmoid sinuses, and eroding the medial wall of the orbit. Complete removal was achieved through endoscopic sinus surgery, preserving the orbit. SFS was found on histopathologic examination. After 4 years of follow-up, nasal endoscopy, CT and MRI imaging show no sign of recurrence.

Endoscopy↗
PubMed2006

[Mechanisms and management of hyperacusis (decreased sound tolerance)].

Hyperacusis is a decreased sound tolerance. Prevalence of the disease is described in 9-15% of the population, but this percentage increases among the tinnitus patients. Pathophysiological mechanisms involve some disruptions in the amplification and regulation processes of the external hair cells or affect the central sound processing at the subcortical level. The role of the serotonin, also involved in other diseases related with hyperacusis (migraine, depression), can be crucial in this disorder. Other theories confirm the effect of the endorphins that activate the excitatory function of the glutamate, the auditory neurotransmitter, increasing its toxicity. The activation of the limbic and autonomic nervous systems produces the emotional reaction of the hyperacusis (anxiety, fear and depression). Proposed treatments are based on acoustic stimulation by a progressive introduction of sound (tinnitus retraining therapy TRT). Noise generators and hearing aids can be fitted in severe cases. The role of some drugs involved in the metabolism of the serotonin open new approaches for the management of hyperacusis.

Humans↗
PubMed2006

Auditory discrimination therapy (ADT) for tinnitus managment: preliminary results.

CONCLUSION: This clinical assay has demonstrated the efficacy of auditory discrimination therapy (ADT) in tinnitus management compared with a waiting-list group. In all, 43% of the ADT patients improved their tinnitus, and its intensity together with its handicap were statistically decreased (EMB rating: B-2). OBJECTIVE: To describe the effect of sound discrimination training on tinnitus. ADT designs a procedure to increase the cortical representation of trained frequencies (damaged cochlear areas with a secondary reduction of cortical stimulation) and to shrink the neighbouring over-represented ones (corresponding to tinnitus pitch). STUDY DESIGN: This prospective descriptive study included 14 patients with high frequency matched tinnitus. Tinnitus severity was measured according to a visual analogue scale (VAS) and the Tinnitus Handicap Inventory (THI). Patients performed a 10-min auditory discrimination task twice a day for 1 month. Discontinuous 8 kHz pure tones were randomly mixed with 500 ms 'white noise' sounds through a MP3 system. ADT group results were compared with a waiting-list group (n=21). RESULTS: In all, 43% of our patients had improvement in their tinnitus. A significant improvement in VAS (p=0.004) and THI mean scores was achieved (p=0.038). Statistical differences between ADT and the waiting-list group have been proved, considering patients' self-evaluations (p=0.043) and VAS scores (p=0.004). A non-significant reduction of THI was achieved (p=0.113).

Adult↗
PubMed2005

Respirometry for assessing the biodegradation of petroleum hydrocarbons.

The respiration method using the Micro-Oxymax respirometer was applied to evaluate the bioremediation potential of hydrocarbon-contaminated soils in two biopiles at the oil refinery in Czechowice-Dziedzice, Poland. In biopiles 1 and 2, two different technologies, i.e., enhanced (engineered) bioremediation and monitored natural attenuation (MNA) were used, respectively. In biopiles 1 and 2, the bioremediation process lasted 6 years and 8 months, respectively. The biodegradation of petroleum hydrocarbons was evaluated on the basis of CO2 production and O2 uptake. The CO2 production and O2 consumption rates during hydrocarbon biodegradation were calculated from the slopes of cumulative curve linear regressions. The results confirmed the hydrocarbon biodegradation process in both biopiles. However, in biopile 2 the process was more effective compared to biopile 1. In biopile 2, the O2 consumption and CO2 production means were 3.37 and 2.4 milliliters per kilogram of soil (dry weight) per minute, respectively. Whereas, in biopile 1, the O2 consumption and CO2 production means were 1.52 and 1.07 milliliters per kilogram of soil (dry weight) per minute, respectively. The mean biodegradation rate for biopile 2 was two times higher--67 mg hydrocarbons kg d.w.(-1)day(-1) compared with biopile 1, where the mean was 30 mg hydrocarbons kg d.w.(-1)day(-l). The results were correlated with petroleum hydrocarbon concentrations and microbial activity measured by dehydrogenase assay.

Biodegradation, Environmental↗
PubMed2005

The effect of spinning forces on spider silk properties.

A new forced silking procedure has been developed that allows measurement of the low forces involved in the silking process and, subsequently, retrieval and tensile testing of the samples spun at the measured silking forces. A strong correlation between silking force and tensile behaviour of spider silk has been established. Fibres spun at high silking force--compared with the conventional yield stress--are stiff and show stress-strain curves previously found in forcibly silked fibres. By contrast, fibres spun at low and very low silking forces are more compliant, and their tensile behaviour corresponds to that of fibres naturally spun by the spider or to fibres subjected to maximum supercontraction, respectively. It has also been found that samples retrieved from processes with significant variations in the silking force are largely variable in terms of force-displacement curves, although reproducibility improves if force is re-scaled into stress. Fibres retrieved from processes with constant silking force show similar tensile properties both in terms of force-displacement and stress-strain curves.

Animals↗
PubMed2004

The molecular basis of succinic semialdehyde dehydrogenase deficiency in one family.

Succinic semialdehyde dehydrogenase (SSADH) deficiency has predominantly neurological consequences, affecting psychomotor, speech and language development. Recently, two clinical reviews summarized the features of this disease and their relative frequency [Neurology 60 (2003) 1413; Ann. Neurol. 54 (2003) S73]. The molecular genetics of SSADH deficiency is still being explored. We describe the molecular basis of this defect in a Tunisian female child presenting with a mild phenotype. A small scale deletion in exon 10 of the gene led to a frameshift that predicts premature termination of the resulting putative protein. The parents were shown to be heterozygotes for this deletion, supporting its causative role.

Aldehyde Oxidoreductases↗
PubMed2004

[Usefulness of the new classification for regional extension on CT of head and neck cancer].

OBJECTIVE: To present the usefulness of the new classification of neck nodes based in commuted tomography (CT). MATERIAL AND METHODS: We present several illustrative images showing neck nodes in each of the new levels (Ia, Ib, IIa, IIb, III, IV, Va, Vb, and VI) as an adjunct to nodal classifications. RESULTS AND CONCLUSION: An imaging-based classification for the cervical nodes allows to know much better their distribution along the neck, helping to find correlation between clinical, radiological and surgical findings.

Head and Neck Neoplasms↗
PubMed2004

[Medullar carcinoma of the thyroid gland: surgical treatment of mediastinal metastases].

Metastatic medullary carcinoma is related to very bad prognosis. Surgery, associated or not to radiotherapy, may be effective in controlling metastasis due to local invasion, as in mediastinal extension. We present a case of medullary carcinoma with mediastinal disease that was treated through mediastinal dissection following by complimentary radiotherapy. After three years of follow-up, the patient remains free of recurrence, although calcitonin levels have not become normal yet.

Carcinoma, Medullary↗
PubMed2003

[Cost-efficiency analysis of treatment of otitis media with effusion in children].

Otitis media with effusion is a common disorder in children, associated to hearing loss and recurrent acute otitis media. It has three basic treatments: Spontaneous resolution, oral antibiotics and surgery including adenoidectomy and/or grommets insertion. Through a sensibility analysis on a theoretical group of 1000 patients our aim is to study the cost-effectiveness of the different therapeutic options, evaluating direct and indirect costs, and identifying the most efficient option (cost-effective). We analysed effectiveness and variable costs of each arm of the decision tree, considering initial and rescue treatments. As expected, effectiveness grows up to the most through treatment, including adenoidectomy and grommets insertion, from 92% to 98% of children treated. Nevertheless, unitary cost of each child treated also increases, from 302 to 401 euros; that is, choosing the most cost-effective treatment enables to save approximately 100 euros per child. But, fixed costs, which are much higher (600 euros per child), will not change, limiting our management resources.

Adenoidectomy↗
PubMed2003

[Multi-sensory interaction in tinnitus: visual evoked potentials and somatosensory stimulation].

Anomalous cross-modal interactions along the audiovestibular, visual and soma-tosensorial pathways could be the responsible for aberrant signals, clinically expressed as phantom perceptions. This results in tinnitus that can be modified by gaze movements or somatosensorial stimulation through skin, orofacial (jaw) and cervical movements. This phenomenon has also been described in some patients with acute unilateral deafferentation of the auditory peripheral system as a result of surgery to remove a tumour in the posterior fossal. Neuroimaging preliminary studies (PET, f-MRI) describe multisensorial interactions and cortical reorganisation processes in chronic tinnitus. Treatment approaches are still unknown although counselling regarding the benignity of the process and the high percentage of habituation to the symptom is the most effective framework. We present our experience in four cases.

Adult↗
PubMed2003

[Study of hyperacusis at a tinnitus unit].

OBJECTIVES: Description of the epidemiological and clinical characteristics of hyperacusis in a tinnitus clinic unit. STUDY DESIGN: Transversal descriptive. PATIENTS: Two hundred and fifty patients referred to our Tinnitus Unit a Teaching Hospital, between January 1999 and December 2000. OUTCOME MEASURES: Questionnaires to evaluate hyperacusis and tinnitus interference in life quality. Epidemiological and audiological data as well as tinnitus characteristics in hyperacustic patients are reported. RESULTS: Sixty three percent of the patients showed hyperacusis according to sound threshold level. Hearing loss was present in 83%. Discomfort with background noise was referred in 54% of cases and 52% avoided at least one daily activity because of this discomfort. Tinnitus in hyperacusis population showed a disability level of 47% using the Tinnitus Handicap Inventory (THI). CONCLUSIONS: A physiopathological relation between tinnitus and hyperacusis could be explained by the high prevalence of both symptoms in the same population. It is necessary to agree in the criteria to define hyperacusis as well as for the evaluation of its effect in quality of life. The tinnitus retraining therapy (TRT) is the more accepted hyperacusis treatment approach in the literature.

Adult↗
PubMed2003

[The Connecticut Chemosensorial Clinical Research Center olfaction test: values in healthy volunteers].

OBJECTIVE: To know the values of the olfactory test (CCCRC) performed in healthy people. To analyse how the age and sex affect the test. MATERIAL AND METHODS: Descriptive study in 100 volunteers with no olfactory disorders. We used CCCRC olfactory test, which it has an odor threshold component, an odor identification component and a composite score. We analysed how age and sex variables affect olfactory test data, listing a t-Student test. The size sample is calculated to 0.05 alfa error. RESULTS: Threshold test data mean was 5.8. Identification test data mean was 7.5. Composite score mean was 6.7. CONCLUSION: Age is a significant factor in our study but not sex. Sample size is sufficient to analyze normal values. Our results are similar to other authors.

Adolescent↗
PubMed2003

Bilateral parotid cysts as presentation of Sjögren's syndrome.

We present a case of a 40-year woman with bilateral parotid salivary gland enlargement as presentation of primary Sjögren's syndrome. Computed tomography (CT) and magnetic resonance imaging (MRI) showed parotid cysts, suggestive of cystic benign lymphoepithelial lesions. A sub-labial biopsy confirmed the syndrome. After 24-month follow-up, the left parotid cysts remain the same, whereas other cysts have appeared in the right parotid gland. Parotid involvement in Sjögren's syndrome is discussed.

Adult↗
PubMed2003

Cross resistance to ALS-inhibiting herbicides in Euphorbia heterophylla L. biotypes resistant to imazethapyr.

The effect of weeds on the diminution of agricultural production is considered to be between 30 and 50%. Imazethapyr is a herbicide which acts on the enzyme ALS, the first common enzyme in the biosynthetic pathway of valine, leucine and isoleucine. Euphorbia heterophylla is a common species in soybean fields in Brazil and different populations resistant to herbicides of the sulfonylurea and imidazolinone groups are currently being reported. The objectives of this work were: to determine the resistance of three different biotypes named RI, RII and RII to the herbicide imazethapyr: to establish the level of resistance to this herbicide, and to evaluate the behaviour of the biotypes to other herbicides with a similar mode of action. The response of plants treated with imazethapyr confirmed the existence of resistance in the biotypes denominated as RI, RII and RIII. The imazethapyr concentration required to reduce the activity of the enzyme ALS by 50% (I50) should be greater than 500 microM for biotypes RI, RII and RIII and 39.47 microM for the susceptible biotype. Applications made in the greenhouse at field doses of ALS inhibiting herbicides showed cross resistance in the case of imazamox and imazamethabenz but not in the cases of the other ALS inhibitor herbicides used. ALS activity results demonstrated that the imazethaphyr resistance in different biotypes of E. heterophylla is target site mediated.

Brazil↗
PubMed2002

[Diagnostic evaluation of nasopharyngeal carcinoma: role of Epstein-Barr virus].

We present a retrospective series of 27 nasopharyngeal carcinomas, selected from those attended at Ramón y Cajal Hospital between 1977 and 1996, with the aim of review the role of the study of Epstein-Barr virus in the diagnostic process of nasopharyngeal carcinoma. Twenty-seven patients, ranging from 14 to 81 years, with an average age of 50 years were selected. Male/female ratio was 1,7. All but one case were Caucasian. A neck mass was the first symptom in 40% of cases, with a mean diagnostic delay of 17 months. Only 8 cases (23%) did not exhibit neck nodes at the moment of diagnosis. CT and MRI were essential to establish staging: 5 stage I, 7 stage II and 15 stage IV, due to regional extension and/or bone erosion. Radiotherapy was employed in all cases, helped by chemotherapy in 20% of them. With a mean follow-up of 62 months, 5-years survival was 32% (IC 14,06-52,09). Of 27 cases of nasopharyngeal carcinoma 4 were differentiated (type I), 2 moderately differentiated (type II) and 22 undifferentiated (type III). While LMP-1 was only expressed by 41% of cases, PCR detected Epstein-Barr virus genome in 26 cases (96%) and in situ hybridization for EBERs was positive in all cases. Thus, all nasopharyngeal carcinomas were related to Epstein-Barr virus. Expression of LMP-1 seemed to worse the prognosis of nasopharyngeal carcinoma.

Adult↗