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Biomedical subjects

A Giovanni

Publications and source records attributed to A Giovanni.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Forcing the voice and variance of speed: correlation between the speed of displacement of the center of gravity and the work of the postural muscles].

Using stabilometry, our experimental protocol was designed to demonstrate a quantitative parameter of posture to study forcing of the voice. Analysis of the graphs has shown a perfect correlation between increases in variance of the speed of displacement of the centre of gravity and the increase in the electrical signal from the postural muscles, which is evidence their activation during forcing of the voice. As well as the clinical applications of this protocol, it seems necessary to undertake other studies such cinematography recording of respiration.

Adult↗
PubMed1999

Involvement of cell cycle elements, cyclin-dependent kinases, pRb, and E2F x DP, in B-amyloid-induced neuronal death.

Previous evidence by others has indicated that a variety of cell cycle-related molecules are up-regulated in brains of Alzheimer's disease patients. The significance of this increase, however, is unclear. Accordingly, we examined the obligate nature of cyclin-dependent kinases and select downstream targets of these kinases in death of neurons evoked by B-amyloid (AB) protein. We present pharmacological and molecular biological evidence that cyclin-dependent kinases, in particular Cdk4/6, are required for such neuronal death. In addition, we demonstrate that the substrate of Cdk4/6, pRb/p107, is phosphorylated during AB treatment and that one target of pRb/p107, the E2F x DP complex, is required for AB-evoked neuronal death. These results provide evidence that cell cycle elements play a required role in death of neurons evoked by AB and suggest that these elements play an integral role in Alzheimer's disease-related neuronal death.

Alzheimer Disease↗
PubMed1999

Nonlinear behavior of vocal fold vibration: the role of coupling between the vocal folds.

Coupling between the vocal folds is one of the nonlinear mechanisms allowing regulation and synchronization of mucosal vibration. The purpose of this study was to establish that modulations such as diplophonia and abnormalities observed in vocal signals that may be observed in some cases of laryngeal pathology can be considered as nonlinear behavior due to the persistence of some physical interaction (coupling). An experimental model using excised porcine larynx was designed to create tension asymmetry between the vocal folds and to obtain vocal signals with modulations. Signals were analyzed by spectral analysis and the phase portrait method. Results were compared with computer-generated synthetic signals corresponding to nonlinear combinations of sinusoid signals. Under these conditions, evidence of nonlinear behavior was detected in 85% of experimental signals. These findings were interpreted as a demonstration of vocal fold interaction. Based on these findings, the authors conclude that (1) coupling must be taken into account in physical models of laryngeal physiology, and that (2) methods of nonlinear dynamics may be used for objective voice analysis.

Animals↗
PubMed1999

Determination of largest Lyapunov exponents of vocal signal: application to unilateral laryngeal paralysis.

It has been shown that voice signal abnormalities, particularly in unilateral laryngeal paralysis (ULP), are not always randomly distributed and that "statistical" indexes of regularity, such as jitter and shimmer, may be unreliable in these cases. The techniques of nonlinear dynamics, particularly phase portraits, have been used to demonstrate that some of the abnormalities observed were the consequence of nonlinearity of glottic function. From a theoretical point of view, determination of Lyapunov exponents allows quantification of the complexity of the phase portraits. The authors studied vocal signals recorded in 12 normal subjects and 26 patients with ULP and calculated the largest Lyapunov exponent (LLE). In normal subjects, LLE mean value was 0.380 (SD = 0.182). In patients with ULP, LLE mean value was 0.570 (SD = 0.337). The difference is significant at P = 0.031. Determination of LLE was compared to more "classical" indexes such as jitter and oral airflow during phonation. A principal component analysis showed that information contained in LLE was not redundant but complementary to the other parameters.

Adult↗
PubMed1999

Quantitative voice analysis in the assessment of bulbar involvement in amyotrophic lateral sclerosis.

Bulbar and pseudobulbar symptoms are diagnostic criteria of amyotrophic lateral sclerosis (ALS). One of the earliest symptoms of bulbar involvement is voice deterioration. Until now voice assessment in ALS patients has been done mainly by perceptual analysis. The objective parameters, including acoustic measures, one aerodynamic measure and the maximal phonation time, have been measured only in a few small series of patients. The first purpose of this prospective study was to determine which vocal parameters discriminate ALS patients with bulbar involvement from control patients. The second was to identify sensitive parameters for early detection of voice deterioration due to bulbar involvement in pre-symptomatic ALS patients. The voices of 63 female ALS patients, including 40 with bulbar symptoms (sALS patients) and 23 without bulbar symptoms (aALS patients), were studied using an objective voice analysis system that allows simultaneous analysis of acoustic and aerodynamic parameters. Measurements were compared with those obtained in 40 normal female subjects (control patients). Five of eight acoustic parameters were significantly different among the three groups: jitter, coefficient of variation for frequency, shimmer, number of harmonics, and maximum phonatory frequency range. Three aerodynamic parameters, phonatory airflow, cycle-to-cycle variation for phonatory airflow, and coefficient of variation for phonatory airflow were significantly different between sALS patients and control patients. No aerodynamic parameter allowed discrimination between aALS patients and control patients. This study shows that acoustic parameters are more sensitive than aerodynamic parameters for early detection of bulbar involvement. Nevertheless, the measurements used can predict bulbar involvement in 73% of those in the sALS group, but only in 52% of those in the aALS group.

Aged↗
PubMed1999

Clinical experience with Gore-Tex for vocal fold medialization.

OBJECTIVES/HYPOTHESIS: Present clinical experience with vocal fold medialization under local anesthesia using a Gore-Tex implant. The procedure consists of placing the implant into a pocket formed by dissection of the inner perichondrium of the thyroid cartilage through a small window made in the thyroid ala. STUDY DESIGN: During 2 years, we used this technique preferentially in 13 of the 16 cases of vocal fold medialization (three patients underwent Teflon injection because of a contraindication to local anesthesia). Follow-up was longer than 3 months in 11 cases (mean, 13 mo). METHODS: Vocal result was analyzed by the means of perceptual analysis and by the measurement of jitter factor. Glottal leakage was evaluated perceptually using videolaryngoscopy, and oral airflow was measured during the production of a vowel. In cases with preoperative aspiration, videofluoroscopy was performed. RESULTS: Implantation was successful in all but one patient in whom extrusion of the implant material occurred. In the latter case, the implant was removed and the patient recuperated his preoperative voice without any other complication. In the 10 other cases, voice improvement assessed by perceptual and objective evaluation was satisfactory. CONCLUSIONS: Results compare favorably with those of endoscopic techniques using Teflon or collagen and laryngeal frame surgery techniques using silicone or cartilage. We conclude that Gore-Tex implantation is a simple, reproducible, and minimally invasive procedure for management of selected cases of vocal fold unilateral paralysis in the abductory position.

Adult↗
PubMed1999

Objective aerodynamic and acoustic measurement of voice improvement after phonosurgery.

HYPOTHESIS: Objective analysis of the outcome of phonosurgery is needed to allow comparison of different surgical techniques or indications, or both. We tried to demonstrate that measurement of mean oral airflow during the production of a sustained vowel could be used in combination with acoustic measurements such as jitter or shimmer for assessment of voice improvement after phonosurgery. STUDY DESIGN: This prospective study included 27 consecutive patients who underwent phonosurgery during a 3-month period. METHOD: Perceptual analysis served as the "gold standard." Objective measurements (oral airflow, jitter, shimmer) on the most stable portion of a sustained vowel /a/ were made using the EVA system (SQ-Lab, Aix-en-Provence, France). RESULTS: Oral airflow was significantly greater in patients with poor perceptual results than in patients with good perceptual results. Jitter and shimmer were not significantly different because of the dispersion of the values. Discriminant factorial analysis showed that a combination of jitter, shimmer, and oral airflow was able to identify patients with good or poor perceptual results in 77% of cases. CONCLUSIONS: Oral airflow allows simple, quick, and reliable assessment of the outcome of phonosurgery and can be used in everyday clinical practice.

Female↗
PubMed1999

Comparison of different voice samples for perceptual analysis.

Choice of voice sample material can influence perceptual judgments by a jury. The twofold purpose of this study was first to validate the pertinence of a sustained vowel for perceptual voice analysis in French speakers and second to test the hypothesis that use of only the stabilized portion of the vowel would lead to underestimation of dysphonia. Voice samples were recorded in 60 dysphonic patients and 20 normal controls. Three different sample materials were obtained for each subject, i.e. connected speech, a sustained vowel including both the initial and stable portion (complete sustained vowel), and a sustained vowel including only the stable portion (stabilized sustained vowel). The jury was composed of 7 experienced listeners. Jury consistency was measured as a percentage of agreeing judgments for the same subject. No difference in consistency was observed using the three sample materials. Judgments on stabilized sustained vowels were confirmed as less severe than judgments on connected speech. Judgments on complete sustained vowels were comparable to judgments on connected speech.

Adult↗
PubMed1999

[The use of calvarial bone in nasal reconstruction].

Twenty-seven nasal reconstructions with parietal bone graft performed between January 1989 and January 1995 were analyzed retrospectively. No complications involving parietal bone were observed. After a 2-year follow-up there have been no cases of shifting, extrusion or resorption of the rhinoplasty. Our experience shows that calvarial bone is an ideal material for nasal reconstruction bone grafts.

Adolescent↗
PubMed1999

[X-ray imaging in assessing the extent of laryngeal cancer].

Partiel surgery of the larynx for cancer should achieve the same carcinological control as total laryngectomy, while at the same time preserving the voice and swallowing. Establishing the extent of the tumour and its relationships with the anatomical structures of the larynx allows a treatment plan to be formulated. Decisions are taken in the light of investigation in which modern imaging plays a fundamental part. The authors have made a comparison of the relative value of CT scanning and MRI as a function of the area involved in the lesion. At present MRI is required only when there is uncertainly of the extent of the subglottic extension, or invasion of the cartilages. We give a prediction of the development of the technique of vitual endoscopy, which will yield a three-dimensional view of the relationships between the tumour and the cartilaginous structures.

Humans↗
PubMed1999

[Extensive rhinectomy. Apropos of 7 cases].

We report our experience in reconstructive surgery after total rhinectomy. Reconstructive surgery is performed after large excision and negative marginal biopsy results. The three layers of the nose (mucosal, osteocartilagineous and cutaneous) are restored by mucosal and cutaneous flaps and osteocartilaginous grafts. Carcinologic and cosmetic results are satisfactory but functional results may yet be improved.

Adult↗
PubMed1999

[Intralesional injection of vinblastine in treatment of laryngeal Kaposi sarcoma associated with AIDS].

Kaposi's sarcoma (KS), is the most frequent malignant neoplasm associated with acquired immunodeficiency syndrome (AIDS). Classically arising in the skin, mucosal lesions are seen in 50 percent in oral cavity. KS rarely involves the larynx (37 cases have been reported in the world literature), when KS occurs in the larynx airway compromise can be a serious threat and immediate treatment is necessary. We report one case of KS of the supraglottic larynx, and intralesional injections were performed. A complete response was noted eleven months later. Although several modes of treatment are available (radiation therapy, systemic chemotherapy) to manage KS, intralesional injections with vinblastine sulfate may after an effective therapeutic alternative.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Amyloid beta-peptides inhibit Na+/K+-ATPase: tissue slices versus primary cultures.

Abeta1-40 (20 microM) has been reported to selectively inhibit Na+/K+-ATPase activity in rat primary hippocampal cultures after 2-6 days of exposure. We expanded these studies to include Abeta's effects on Na+/K+-ATPase activity in rat primary cortical cultures and hippocampal slices, and we correlated these effects with estimates of cell survival in rat brain primary cultures. Using optimized assay conditions, a 5-day exposure to 50 microM Abeta 25-35, 20 microM Abeta 1-40, and 20 microM Abeta 1-42 decreased Na+/K+-ATPase activity in rat primary cortical cultures 66%, 60%, and 22%, respectively. Abeta 25-35 (50 microM) at 24 h was the only condition that caused inhibition of Na+/K+-ATPase activity in the absence of cell death, defined as an extracellular shift in the localization of the cytoplasmic enzyme lactate dehydrogenase (LDH). We also found that hippocampal slices were sensitive to Abeta, exhibiting a 40-60% reduction in membrane Na+/K+-ATPase activity when exposed to 1-30 nM of Abeta 1-40 for 60 min. This inhibition was not readily reversible, as it withstood homogenization and repeated dilution and centrifugation. Additionally, this inhibition occurred only after amyloid incubation with intact hippocampal slices, not with disrupted membranes. The inhibition of Na+/K+-ATPase in brain slices by physiological, low nM concentrations of Abeta 1-40 is consistent with effects on neurotransmitter release and intrasynaptosomal calcium responses.

Amyloid beta-Peptides↗
PubMed1998

[Geometric modeling and virtual endoscopy of the laryngo-tracheal lumen from computerized tomography images: initial applications to laryngo-tracheal pathology in the child].

Endoscopy is an essential stage in the management of laryngo-tracheal disorders in the infant, but remains a difficult procedure. CT scanning is used to confirm the abnormality and to estimate the degree to which the airway is compromised. The authors describe virtual endoscopy of the larynx and trachea based on a mathematical model, itself constructed from CT images. This work is based on a methodology developed at the Hôpital de la Timone for modelling the aorta. By applying this methodology to the study of laryngo-tracheal disorders, it is possible to establish the relevant pre-treatment measurements (length, diameter, degree of narrowing). This preliminary study has been carried out in 8 cases, in parallel with their clinical treatment. It has allowed us to single out the 3 typical examples which are presented in detail, and to show the advantages of this new approach: immediate and precise measurements, presentation which it is not possible to achieve with conventional techniques of 3-dimensional imaging, and demonstration of the degree of encroachment of the externe stenoses. When taken as part of the management of the patient, this technique complements the findings of real endoscopy, or replaces them, thus reducing the costs of hospital admission and the risks inherent in this procedure.

Adolescent↗
PubMed1998

[KTP laser in the upper airways in children: preliminary study on 27 lesions].

The KTP Laser was recently introduced in otolaryngology, and is increasingly used. This report describes treatment of 27 upper airway lesions in 24 children using KTP Laser over a two year and half period at the Children's Hospital of La Timone in Marseille. Comparison of results with CO2 Laser were made for the three most frequent pathologies of the series which were choanal atresia (n = 14), laryngotracheal stenosis (n = 6) and laryngeal paralysis (n = 3). The convenience of fiber delivery, concomitant telescopic control and low grade oedematous reaction are the main advantages over the CO2 Laser. As reported in the literature, we observed that healing was longer for KTP Laser than for CO2 Laser. Delay to healing may be an advantage in the management of choanal atresias and laryngeal stenosis.

Child↗
PubMed1998

Non linear behavior of vocal fold vibration in an experimental model of asymmetric larynx: role of coupling between the two folds.

One of the main factors involved in the laryngeal dynamic's non-linearity is the coupling between the two vocal folds. Evaluation of the different coupling elements requires various investigations. The present work evaluate the non-linearity effects in clinical situations such as unilateral laryngeal paralysis using Lyapunov's coefficients. It also demonstrate the coupling effects on excised larynx made experimentally asymmetrical, using a specially designed device to measure vibrations from each vocal fold (opto-reflectometer).

Animals↗
PubMed1998

[Contemporary postural and segmental modification of forced voice].

The forced voice corresponds with increased peri-laryngeal tension during phonation caused by inappropriate muscle action. It is usually accompanied by a characteristic posture (the face thrust forwards, tension in the neck muscles etc...). This posture may cause dysfunction of the cords themselves, leading to dysphonia, and perhaps requiring laryngeal microsurgery. Our project aimed to put forward and validate a system of objective, non-invasive measurements of the postural features of the forced voice, in order to improve the management of these patients. The study was prospective, comparing a control group with no previous vocal problems with a group of patients with problems of laryngeal dysfunction. We carried out a number of simultaneous measurements of postural and segmental activity during phonation, using in parallel an accelerometer, a method of cine-analysis, and a postural platform. Recordings were made during phonation, but only analysed during the resting phase. It turned out that the speed of displacement of the centre of gravity was the most useful discriminating factor. The mean value was 0.07 (displacement type 0.126) for the control group, and 0.32 (displacement type 0.211) for the patient group. The discrimination between these two groups was significant (p < 0.001, Mann-Whitney test). The reliability of this measurement allows us to envisage the inclusion into the clinical investigation package of measurements of the postural and segmental changes in the forced voice.

Adolescent↗