Search PubMed⌕ Search

Biomedical subjects

A Giovanni

Publications and source records attributed to A Giovanni.

At least 37 records · Page 2Linked to original sources
PubMed2002

[15 years experience with microvascular free tissue transfert for repair of head and neck cancer defects].

We present the modalities and results obtained with free flap reconstruction of head and neck cancers defects. This retrospective review of 165 free transfers performed between 1984 and 1999 included 89 radial forearm flaps (54%), 38 latissimus dorsi flaps (23%), 28 osteomyocutaneous flaps (17%), 6 omentum flaps (4%), 2 jejunum flaps, and 2 cutaneous scapular flaps. Indications were orobuccopharynx (34%), hypopharynx (24%), mandible (17%), craniofacial (15%) and skin (10%) defects. Flap failure rate was 9%. Reconstruction of a radiated site was a statistically significant indicator of flap failure. Four types of free flaps were preferred for reconstruction of head and neck cancer defects. The radial forearm flap was used as a lap flap for the orobuccopharynx, the tubuled radial forearm flap for reconstruction of the digestive tract after total pharyngolaryngectomy, the osteomyocutaneous free fibular flap for pelvimandibulectomy, especially for the anterior arch, the latissimus dorsi flap to fill craniofacial defects, and the free omentum flap for craniofacial complications after radiotherapy.

Adenocarcinoma↗
PubMed2002

[Non-linear model of glottic vibration. Potential clinical implications].

Glottic vibration is governed by a certain number of physical laws which in general correspond, as far as myo-elastic theory is concerned, with the laws of passive vibration of an elastic body under the influence of the expired air. Some of these laws are non-linear, especially those that deal with the exchange of energy between the expired air and the vocal folds. This non-linearity is specially important when it comes to the key concepts of the phonatory threshold and the passive synchronisation of the vocal cords. Based on their experimental work, which has been presented previously, the authors propose a mixed model, which is both linear and non-linear, like the oscillators of Van der Pool. This model is known as Slip-Stick.

Glottis↗
PubMed2002

[Comparative study of respiratory mechanisms between professional lyrical singers and beginners].

The apprenticeship for classical singing requires years of training due to its complexity. This training is directed at the different levels of the vocal apparatus: the source of energy or air flow (lungs), the vibrator (vocal cords) and the resonators (bucco-pharyngeal cavity). For this study we have concentrated on the first level, that is, respiration. When a greater demand of vocal activity is required respiration becomes more sustained and more complex; this is when difficulties may be observed. Singers overcome these difficulties through different strategies according to their level of vocal training. Our study compared respiratory strategies used by professional singers and singing students (first year conservatoire students) during singing tasks; none of the subjects had any history of vocal pathology. Electromyographic analysis of muscle activity was registered for the rectus abdominals muscle, external oblique muscle and transverse muscle with surface electrodes. Kinetic analysis was used to measure thoracic cage displacement: pressure sensitive belts were placed around the pubis, the epigastric region and thorax. The subjects were asked to perform two vocal tasks: vocalization of a sustained "i" and singing of an extract of a vaccaï. Results were compared between the 7 professional singers and the 6 singing students. They allowed us to confirm the existence of distinct respiratory strategies according to the level of vocal training, as described in literature. Professional singers inhibited the activity of their rectus abdominals muscles during singing and used mostly their external oblique and transverse muscles, thus, sustaining an expanded ribcage and a longer expiratory breath. Singing students, on the other hand, worked intensively all the abdominal muscles leading to a collapse of the ribcage. Management of air was more difficult and breath was shorter. Future studies will consider a larger population sample in order to define quantitative parameters that might allow a significant differentiation of respiratory strategies between professional singers and singing students.

Adult↗
PubMed2002

[Importance of tussometry in unilateral laryngeal paralysis].

Cough is a physiological gesture witch requires a perfect laryngeal competence. Tussometry was described as a reliable and reproducible method of analysis based on the measure of oral air flow rate during cough. This test allows to quantify the efficiency of laryngeal occlusion in normal situation and in case of unilateral laryngeal paralysis. The measure of the time lag between the beginning of the cough and the maximal air flow rate (peak value time) is the most reliable parameter (8). Present study is designed to asses the reproducibility of tussometry realized on a vocal analysis workstation EVA II and to test the efficiency of intracordal injection of autologus fat in case of unilateral laryngeal paralysis following thoracotomy. 10 control subjects were recorded at two moments. 6 patients presenting unilateral laryngeal paralysis following thoracic surgery were recorded before and after injection of autologus fat in the paralysed vocal cord. Reproducibility of tussometry is good (r = 0.96). The mean peak value time is significantly improved (p = 0.048). In conclusion, tussometry is a reliable routine test on EVA III workstation. Intracordal autologus fat injection improves occlusive function of larynx during cough in case of unilateral paralysis.

Adipose Tissue↗
PubMed2002

Phonatory threshold pressure in a healthy population before and after aerosol treatment, a preliminary study.

The viscosity of the surface mucus of the vocal cords is one of the important elements for good laryngeal functioning. It has been demonstrated that inhalation of hydrated air increases the phonatory threshold pressure by decreasing viscosity of the mucus (1) leading to a more regular vibration that can be appreciated by jitter (2). In an attempt to correlate the concepts of tissue viscosity and surface mucus considering the theoretical model of vibration we measured the phonatory threshold pressure in 6 healthy female subjects before and after aerosol treatment. We were able to demonstrate that the pressure threshold is lower (3.15 hPa) after aerosol treatment than before (3.79 hPa) and this was statistically significant (p: 0.041). The discussion is based on this decrease of mucus viscosity applied to the physiological concepts necessary to understand glottic vibration.

Adult↗
PubMed2001

Objective voice analysis for dysphonic patients: a multiparametric protocol including acoustic and aerodynamic measurements.

The purpose was to determine the clinical value of a multiparametric objective voice evaluation protocol including acoustic and aerodynamic parameters measured mainly on a sustained /a/. This was done by comparison with perceptual analysis of continuous speech by a jury composed of 6 experienced listeners. Voice samples (continuous speech) from 63 male patients with dysphonia and 21 control subjects with normal voices were recorded and assesed by a jury of listeners. The jury was instructed to classify voice samples according to the G (overall dysphonia) component of the GRBAS score on a 4-point scale ranging from 0 for normal to 3 for severe dysphonia. Objective parameters were recorded on an EVA workstation. As usual with this type of system, parameters were measured mainly on a sustained /a/. Measured parameters included fundamental frequency (F0), intensity, jitter, shimmer, signal-to-noise ratio, Lyapunov coefficient (LC), oral airflow (OAF), maximum phonatory time (MPT), and vocal range (range). Estimated subglottic pressure (ESGP) was determined on a series of /pa/. Discriminant analysis was performed to detect correlation between jury classification and combinations of parameters. Results showed that a nonlinear combination of only six parameters (range, LC, ESGP, MPT, signal-to-noise ratio, and F0) allowed 86% concordance with jury classification. Discussion deals with the relative importance of the different objective parameters for discriminant analysis. Special emphasis is placed on two measurements rarely made in routine clinical workup, i.e., estimated subglottic pressure and Lyapunov coefficient.

Adult↗
PubMed2001

Partial frontolateral laryngectomy with epiglottic reconstruction for management of early-stage glottic carcinoma.

OBJECTIVES: The aim of this study was to demonstrate that partial frontolateral laryngectomy with epiglottic reconstruction (PFLER) is an effective therapeutic option for treatment of T1 and T2 glottic carcinoma. STUDY DESIGN: Retrospective study. METHODS: Between 1982 and 1997, we treated 127 cases of early glottic carcinoma with PFLER. Early glottic carcinoma was staged using the Union Internationale Contre le Cancer TNM classification as either T1N0M0 (62 cases) or T2N0M0 (65 cases). Selection criteria, depending on the limits of exeresis, must remain glottic carcinoma with less than 0.5 cm of anterior subglottic involvement, with no involvement of the supraglottic space or laryngeal side of the epiglottis, with involvement of only one arytenoid, and with good mobility of both arytenoids even if vocal cord mobility is decreased. RESULTS: Postoperative recovery was uneventful in all cases, and all patients but one were able to breath and eat normally. The failure involved a patient with a permanent gastrostomy. As with other partial laryngectomy techniques, the main drawback of PFLER was deterioration of voice quality. All patients presented hoarseness and weakness of the voice. Five-year survival rates calculated according to the Kaplan-Meier method were 91% (standard error, 5%) in the T1N0M0 group and 86% (standard error, 5%) in the T2N0M0 group. No recurrence was observed in the T1N0M0 group. Local control was successful in 92% in the T2N0M0 group after a median follow-up of 5 years. CONCLUSION: These findings show that PFLER is an effective therapeutic option in selected cases of early T1N0M0 or T2N0M0 glottic carcinoma.

Carcinoma, Squamous Cell↗
PubMed2001

Cytochemical study of the involvement of cell organelles in formation and accumulation of fibrillar amyloid in the pancreas of NORbeta transgenic mice.

Phosphatase ultrastructural cytochemistry was used to evaluate the participation of cytoplasmic organelles in the accumulation of fibrillar amyloid beta (Abeta) in exocrine acinar cells and in macrophages of the pancreas of transgenic mice overexpressing a carboxy-terminal fragment of Abeta protein precursor (ABPP). Nucleoside diphosphatase (NDPase) and glucose-6-phosphatase (G6Pase) were used as cytochemical markers of the endoplasmic reticulum (ER), thiamine pyrophosphatase (TPPase) as a marker of the Golgi apparatus (GA), and acid phosphatase (AcPase) as a marker of lysosomes. Monoclonal antibody 4G8 raised against the 17-24 aa sequence of human Abeta protein was used for immunogold localization of fibrillar Abeta. The results of this study indicate that the formation of Abeta in acinar cells occurs directly in the vacuolar areas of the rough ER (RER) without evident participation of the elements of the GA, whereas an intimate structural relation with primary lysosomes suggests their role in modification or digestion of the deposited amyloid. In macrophages, fibrillar amyloid was present in numerous cytoplasmic vacuoles located frequently in close proximity to flattened saccules of the ER. This structural pattern revealed similarity to that observed previously in microglial cells producing fibrillar PrP amyloid in scrapie-infected mice and Abeta in brains of human elderly patients and in Alzheimer's type brain pathology.

Acid Anhydride Hydrolases↗
PubMed2001

[Reconstruction of the palate vault by free forearm cutaneous flap in oncology].

Surgical reconstruction after partial superior maxillectomy raises a major functional challenge and postoperative recovery implies difficult prosthetic rehabilitation. Between 1989 and 2000, 23 free radial forearm flap reconstruction were performed for palate defects. Twenty-two patients were treated for cancer-related defects and one patient for a non-malignant tumor. Immediate reconstruction was performed in 21 cases and delayed reconstruction in 2. Radiation therapy had been given prior to surgery in 7 patients, Flap necrosis occurred in 2 patients who had surgery alone. Deglutition and phonation outcome was satisfactory in all patients. Trismus was the most frequent complication (7 cases). The free radial forearm flap is the gold standard surgical treatment for superior maxillary defects. In these patients, and exclusive skin flap enables complete reconstruction.

Adult↗
PubMed2000

E2F1 mediates death of B-amyloid-treated cortical neurons in a manner independent of p53 and dependent on Bax and caspase 3.

Although B-amyloid (AB) is suggested to play an important role in Alzheimer's disease, the mechanisms that control AB-evoked toxicity are unclear. We demonstrated previously that the cell cycle-related cyclin-dependent kinase 4/6/retinoblastoma protein pathway is required for AB-mediated death. However, the downstream target(s) of this pathway are unknown. We show here that neurons lacking E2F1, a transcription factor regulated by the retinoblastoma protein, are significantly protected from death evoked by AB. Moreover, p53 deficiency does not protect neurons from death, indicating that E2F1-mediated death occurs independently of p53. Neurons protected by E2F1 deficiency have reduced Bax-dependent caspase 3-like activity. However, protection afforded by E2F1, Bax, or caspase 3 deficiency is transient. In the case of E2F1, but not with Bax or caspase 3 deficiency, delayed death is accompanied by DEVD-AFC cleavage activity. Taken together, these results demonstrate the required role of E2F1, Bax, and caspase 3 in AB evoked death, but also suggest the participation of elements independent of these apoptosis regulators.

Amyloid beta-Peptides↗
PubMed2000

Guanosine 3',5'-cyclic monophosphate mediated inhibition of cell death induced by nerve growth factor withdrawal and beta-amyloid: protective effects of propentofylline.

Apoptotic cell death has been implicated in Alzheimer's disease pathology and amyloid peptide induced neurotoxicity. We investigated the survival promoting effects of Propentofylline in two models of apoptotic cell death, nerve growth factor withdrawal and beta-amyloid mediated cell death in nerve growth factor differentiated rat pheochromocytoma cell lines. The increase in cell death as measured by lactate dehydrogenase release in response to nerve growth factor withdrawal was suppressed by nitric oxide donor S-nitroso-N-acetylpenicillamine (12.5 to 200 microM) and by 8-bromoguanosine-3',5'-cyclic monophosphate (1.25 to 10mM). Both agents decreased cell death mediated by 25 microM beta-amyloid, suggesting that the protective mechanism involves guanosine -3', 5'-cyclic monophosphate. In support of this hypothesis we can show that S-nitroso-N-acetylpenicillamine increases intracellular levels of guanosine -3',5'-cyclic monophosphate in pheochromocytoma cell lines 3 to 8 fold.Propentofylline, a phosphodiesterase inhibitor, has previously demonstrated neuroprotective activity in stroke models and is a potential candidate for therapeutic treatment in neurodegenerative diseases. The present findings support this claim by providing evidence that Propentofylline has protective effects in both nerve growth factor withdrawal and beta-amyloid mediated cell death. Lactate dehydrogenase release was significantly reduced and caspase-3-like activity was attenuated after cotreatment with Propentofylline. Furthermore Propentofylline dose responsively increases intracellular guanosine-3',5'-cyclic monophosphate levels over the same dose range that provided protection. We hypothesized that guanosine-3',5'-cyclic monophosphate is a key mediator of neuroprotection under these conditions.

1-Methyl-3-isobutylxanthine↗
PubMed2000

Estimated subglottic pressure in normal and dysphonic subjects.

The objective of this report was to study the clinical interest of estimated subglottic pressure (ESGP) with measurements of intraoral pressure according to the "airway interrupted method." Twenty healthy female subjects and 27 dysphonic female patients were included and asked to produce sounds under different conditions of pitch and intensity. The ESGP increased with intensity and slightly with pitch in both patients and controls. A comparison between patients and controls showed significantly higher values of ESGP in patients under all conditions of intensity and pitch. For normal intensity and usual pitch, ESGP has been found to be 6.1 hectopascals (hPa) in control subjects and 8.25 hPa in patients (p = .002). Discriminant analysis of all the measured data showed that data recorded for low intensity (lowest possible intensity without whispering) and high pitch (9 semitones above the usual pitch) were the most discriminant. The authors concluded that ESGP allows good discrimination between dysphonic patients and control subjects and might be included in the basic clinical set of objective parameters.

Adult↗
PubMed2000

Fibrillar amyloid-beta production, accumulation, and recycling in transgenic mice pancreatic acinar cells and macrophages.

Amyloid-beta (A beta) production, accumulation, and recycling were examined by light and electron microscopy in the pancreas of transgenic mice (from 45 days to 22 months of age) that express the gene for the carboxy-terminal fragment of the human amyloid-beta protein precursor. Ultrastructural immunocytochemistry revealed four types of cells accumulating fibrillar A beta 1-40 in cytoplasmic vacuoles: acinar pancreatic cells, macrophages infiltrating stroma, epithelial cells of pancreatic ducts, and blood monocytes/macrophages in the lumen of pancreatic vessels. The ultrastructure of amyloid deposits suggests that each of these four types of cells produces fibrillar A beta. Three basic types of amyloid deposits were distinguished: primary vacuoles in different stages of amyloid aggregation and fibrillization, secondary vacuoles that are the product of fusion of primary vacuoles, and phagosome-like vacuoles with morphologically intact fibrillar amyloid and residues of ingested cells. Amyloid production in acinar pancreatic cells starts in mice younger than 45 days, progresses in 2- to 7-month-old mice, and plateaus in the second year of life. In macrophages, amyloid appears in 60-day-old mice, and the increase in the number of macrophages and the amount of amyloid in their cytoplasm correlates with age.

Aging↗
PubMed2000

[The pectoralis myofascial flap in oropharyngeal and pharyngolaryngeal reconstruction in salvage surgery].

BACKGROUND: The pectoralis major myofascial (PMMF) flap is rapidly mobilized, reliable in a number of clinical situations calling for vascularized soft tissue coverage in the head and neck. Salvage surgery after radiation failures produce salivary fistula, skin flap necrosis, vascular rupture. Use of PMMF improves healing in such cases. METHODS: A retrospective review performed at the university hospital, Marseille, between August 1987 and August 1999, was undertaken in two groups of salvage surgery. Groupe 1: protection of great vessels and fistula prevention after total laryngectomy (TL) and pharyngolaryngectomy (PL). Groupe 2: intra oral and pharyngeal defects reconstruction. Outcomes were classified in three types: type 1 - no complications; type 2 - delayed healing; type 3 - complicated healing. In groupe 2, in six cases the amount of flap contraction was analysed by C.T. scan. RESULTS: 83 PMMF was performed. Groupe 1, 57 cases (TL 28 cases, PL 26 cases); groupe 2, oral cavity défect 9 cases; oropharyngeal défects; 17 cases. There was no flap necrosis or vascular rupture. The donor site complications rate was 9.2%. The overall complications follow up was; groupe 1; type 1: 66%; type 2: 32%; type 3: 2%. In the groupe 2, type 1: 81%; type 2: 19%; type 3: 0%. The flap contracture was 30%. The use of PMMF in salvage surgery must be indicated in all cases after TL or PL, and is an excellent alternative from soft tissue coverage of oropharyngeal defects.

Adult↗
PubMed2000

[Definition of a new temporal voice onset measurement].

The aim of this study was to define a new temporal measurement of voice onset. If in fact it has been established that voice onset contains perceptive information which the listening panel uses to evaluate dysphonia, up till now there has been no objective measurement of this. In order to be able to use instrumental measurement of voice onset, it was first necessary to arrivee at a definition of the limits of onset and end. In electronics, the method of "10%-90%" is used to calculate the rise time (onset) of any signal. It is possible to apply this method to the voice signal using the intensity curve. We have made such measurements on 240 examples of the sustained lal sound produced by 60 dysphonic subjects and 20 normals. The results have shown that measurement of the duration of onset was in the main relevant for the mild (G1) and moderate (G2) dysphonias. We have concluded that the "10%-90%" method allows definition of the contours of onset, and measurement of its duration in a reproducible and standardised way.

Adult↗
PubMed2000

[Visualization of the vibratory movements of the vocal cords under asymmetrical conditions].

In this study, we present a new system for measuring the vibration signal of the larynx which allows the vibration of each vocal cord in an excised larynx to be studied using a method of distant optical measurement. The set-up consisted of an insufflator and a device for immobilising the larynx, together with microprobes capable of creating mechanical pressure at the laryngeal ventricles. The whole system was computer-controlled. The measurements were carried out under normal and asymmetrical conditions on seven excised pig larynges. Measurement of the individual vibration of each vocal cord showed that the transient period of commencement of vibration (vocal onset) is influenced to a significant extent by the degree of asymmetry. Under conditions of extreme asymmetry, movement of the cords appeared to be aberrant, but not random because of the coupling mechanisms which cause "anchoring" of the two cords during the phase of closure. Thus one cord may vibrate at twice the frequency of the other. The method described has given us a better understanding of the mechanism of laryngeal vibration, and one which is in conflict with the theoretical harmonic model in many details.

Animals↗
PubMed2000

[Clinical significance of calculating the coefficients of Lyapunov in the objective assessment of dysphonia].

Measurement of the vibration instability by means of jitter in cases of dysphonia fails to take into account certain features of the vocal signal, such as modulation or bitonatily. These abnormalities appear in jitter measurements as instability, without allowing any differentiation from random instability (to give 'true' instability). The authors suggest the use of the coefficient of Lyapunov, a measurement which is used for nonlinear dynamics. The vocal product of 179 normal and dysphonic subjects has been analysed. The coefficient of Lyapunov and the jitter were measured during the stable period of a sustained 'a' vowel. For the coefficient of Lyapunov, the authors used the algorythm which has been published previously [Giovanni et al, J. Voice 1999;13:341-354]. The measurements were compared with the perceptive analysis of the reading voice by a panel, and divided into four grade (G0 to G3). The coefficient of Lyapunov appeared to be more relevant than the jitter in distinguishing the various perceived grades. Precise recognition of the grade was obtained in 46% using the coefficient of Lyapunov as against only 36% using jitter. The addition of this new index to the existing puriparametric methods of voice analysis seems to be promising.

Acoustics↗