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Biomedical subjects

G Paludetti

Publications and source records attributed to G Paludetti.

At least 37 records · Page 2Linked to original sources
PubMed2001

SPET monitoring of auditory cortex activation by electric stimulation in a patient with auditory brainstem implant.

Auditory cortex activation following multifrequency acoustic stimulation has been evaluated by means of single photon emission tomography (SPET) in one patient before and after an auditory brainstem implant (ABI). No activation could be observed after acoustic stimulation before ABI. After ABI stimulation in the coronal and axial slices, the activation within the temporal cortex contralateral to the stimulated ear was twice (43.76%) that of normal controls (23.94 +/- 2.74%). This marked difference was not present in other selected cortical auditory areas (homolateral temporal, homolateral and contralateral parietal cortices). The temporal cortex was also examined with six consecutive sagittal slices from 18.75 mm up to 56.25 mm lateral to the midline. A very strong activation (51.20%) compared with that of normal controls (9.94 +/- 7.45%) was detected in the 25.26-mm sagittal slice of the temporal cortex contralateral to the stimulated side. The remaining sagittal slices showed an almost normal post-stimulatory activation. As the 25.26-mm sagittal slice corresponds to the medial part of the auditory temporal cortex, its activation suggests that electrode stimulation is concentrated on the region of the cochlear nucleus in which the neurons that transduce high frequencies are located. SPET can be considered useful, in combination with electric auditory-evoked potentials, to obtain information on ABI placement and function, effectiveness of acoustic stimulation, degree of cortical stimulation and tonotopic spatial distribution of auditory cortex activation.

Adult↗
PubMed2001

Effects of contralateral white noise stimulation on distortion product otoacoustic emissions in myasthenic patients.

Myasthenia gravis (MG) induces a reduction of transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) that reverses partially after administration of an acetylcholinesterase (AChE) inhibitor. In normal subjects a contralateral acoustic stimulation (CAS) produces an amplitude reduction of TEOAEs and DPOAEs. This effect, called contralateral suppression (CS), is mediated by the efferent auditory system. Twenty subjects affected by MG underwent DPOAE recording with and without contralateral white noise in a drug-free baseline period ('basal') and 1 h ('post') after administration of a reversible AChE inhibitor. In 'basal' condition CAS did not induce significant DPOAE amplitude changes but a paradoxical slight increase was observed. After drug administration, CAS produced a significant decrease of DPOAE amplitudes for middle frequencies (f(2) between 1306 and 2600 Hz). In normal controls CAS caused a significant decrease (P<0.001) for all frequencies. The amount of CS in controls and in the MG 'post' condition was not significantly different. The increased acetylcholine (ACh) availability following drug consumption seems to partially restore outer hair cell function and enhances their electromotility; a further influx of ACh due to CAS yields to restoration of the CS. These findings also suggest that DPOAEs may be useful in the diagnosis of MG and for monitoring the effectiveness of treatment.

Acoustic Stimulation↗
PubMed2001

The role of cholinergic transmission in outer hair cell functioning evaluated by distortion product otoacoustic emissions in myasthenic patients.

Outer hair cells (OHCs) are the source of otoacoustic emissions, following a tropomyosin-miosin-dependent contraction, which are regulated by the olivocochlear bundle via the release of acetylcholine (ACh). ACh acts on ACh receptors (AChR) located on the OHC post-synaptic membrane. In myasthenia gravis (M.G.) neuromuscular transmission is reduced due to the action of AChR autoantibodies. It has previously been shown that M.G. induces a reduction in transient evoked otoacoustic emissions (TEOAEs), which is reversed after administration of a cholinesterase (AChE) inhibitor. Distortion product otoacoustic emissions (DPOAEs) were recorded before and 60 min after oral administration of 60 mg pyridostigmine bromide in 25 patients with normal hearing affected by M.G. The results were compared with those from 25 age-matched normal controls. Mean values of DPOAE amplitude in myasthenic patients were significantly (p < 0.05) lower at all frequencies before drug administration. All patients showed an overall significant (p < 0.05) increase in DPOAE amplitude after drug administration, although without reaching the control values. Such a recovery was more evident and highly significant (p < 0.01) for middle and high frequencies and could be explained by a higher concentration of ACh receptors in the basal and middle cochlear turns. These data seem to confirm the role of ACh in the neurotransmission of the auditory efferent system and may represent a new in vivo model for the investigation of the physiology of this system.

Acetylcholine↗
PubMed2001

Vestibulo-ocular reflex modification after virtual environment exposure.

Immersion in an illusory world is possible by means of virtual reality (VR), where environmental perception is modified by artificial sensorial stimulation. The application of VR for the assessment and rehabilitation of pathologies affecting the vestibular system, in terms of both diagnosis and care, could represent an interesting new line of research. Our perception of reality is in fact based on static and dynamic spatial information perceived by our senses. During head movements in a virtual environment the images on the display and the labyrinthine information relative to the head angular accelerations differ and therefore a visuo-vestibular conflict is present. It is known that mismatches between visual and labyrinthine information may modify the vestibulo-oculomotor reflex (VOR) gain. We studied the post-immersion modifications in 20 healthy subjects (mean age 25 years) exposed to a virtual environment for 20 min by wearing a head-mounted display. VOR gain and phase were measured by means of harmonic sinusoidal stimulation in the dark before, at the end of and 30 min after VR exposure. A VOR gain reduction was observed in all subjects at the end of VR exposure which disappeared after 30 min. Our data show that exposure to a virtual environment can induce a temporary modification of the VOR gain. This finding can be employed to enable an artificial, instrumental modification of the VOR gain and therefore opens up new perspectives in the assessment and rehabilitation of vestibular diseases.

Adult↗
PubMed2000

Preliminary experiences with contact endoscopy of the larynx.

Nine patients with laryngeal polyps, four with Reinke's edema, three with leukoplakia, one with papilloma and one with malignant tumor were studied by means of laryngeal contact endoscopy during microlaryngoscopy. This technique allowed in vivo and in situ visualization of the superficial layer of the laryngeal epithelium after staining with methylene blue. Cell structures evaluated were the size and color of the nuclei, the nucleus/cytoplasm ratio, nuclear and cytoplasmic contours, the presence of nucleoli, mitoses and keratoses, as well as the microvascular network of the mucosa and superficial cellular changes from normal to pathological. The normal squamous epithelium of the vocal cord showed a homogeneous cellular population with regular nuclear and cytoplasmic morphological characteristics and a uniform nucleus-to-cytoplasm ratio. Specific cellular epithelial patterns and several alterations of the vascular distribution were found in different pathological conditions. Cytological pictures obtained at contact endoscopy were consistent with histological findings in all the patients studied.

Adult↗
PubMed2000

Rhinoscintigraphy: a simple radioisotope technique to study the mucociliary system.

PURPOSE: This was a radioisotope study of nasal mucociliary clearance of total and subtotal nasal obstruction. METHODS: Rhinoscintigraphy was performed by insufflating 1.85 MBq (69 mCi) Tc-99m MAA in 20 patients. Six cases were regarded as the control group, because the presence of small spurs does not affect nasal patency. The remaining 14 patients had various rhinopathic conditions. Two regions of interest were selected, one in the nasal cavity and one in the pharynx. Mucociliary transport speed was calculated. RESULTS: This parameter appeared to be a sensitive index for the assessment of the degree of mucociliary alteration. It showed that polyposis impairs mucociliary transport most severely, thus confirming the results of other published studies. CONCLUSIONS: Rhinoscintigraphy proved to be a reliable, easily reproducible, and harmless method, so it may be used for follow-up examinations in patients who have had surgery of the nose and paranasal sinuses, and for drug therapy of rhinopathic conditions.

Adult↗
PubMed1999

Epidermal growth factor receptor expression in primary laryngeal cancer: an independent prognostic factor of neck node relapse.

Specimens of laryngeal squamous cell carcinoma (LSCC) were examined for epidermal growth factor receptor (EGFR) content using a radioreceptor method; 140 untreated consecutive patients with primary LSCC undergoing initial surgical resection were followed up for a median of 49 months (range 2-84 months) after surgery. Cox univariate regression analysis using EGFR as a continuous variable showed that EGFR levels were directly associated with the risk of lymph node metastasis. A significant relationship between EGFR status and cervical node metastasis was observed. The cutoff value of 20 fmol/mg protein was the best prognostic discriminator. The 5-year metastasis-free survival (MFS) was 66% for patients with EGFR- tumors compared with 15% for patients with EGFR+ tumors. By multivariate analysis, the EGFR status appeared to be a significant independent prognostic factor for MFS. Our results suggest that the assessment of EGFR status at the time of diagnosis may identify a subset of LSCC patients highly susceptible to neck node metastases thus defining therapy accordingly.

Analysis of Variance↗
PubMed1999

Transient evoked otoacoustic emissions (TEOAEs) in new-borns: normative data.

OBJECTIVE: Early diagnosis and rehabilitation of congenital hearing loss are mandatory in order to achieve a satisfactory linguistic and cognitive development. A universal hearing screening in order to identify congenital hearing losses before 3 months of age is required. METHODS: TEOAEs are an easy to perform, short lasting, not invasive and low-cost test with a high sensitivity. 320 at term new-borns (640 ears) without any risk factor for hearing loss underwent TEOAEs. The new-borns were screened 3 days after birth. Those who failed the first test were retested when possible before the discharge from the hospital. ABR was performed 3 months later in cases who failed TEOAE. RESULTS: The median TEOAE sampling time was 98 s, the median test duration was 14 min. The mean stimulus amplitude was 80 dB peSPL in the left ear and 81 dB peSPL in the right ear, noise levels within the external meatus during sampling were 44 dB SPL on the right ear and 43 dB SPL on the left one, noise contained within the response (A-B difference) was 8.65 dB SPL in the left ear and 8.74 dB SPL in the right ear, mean TEOAEs amplitudes were 21.49 dB SPL and 21.78 dB SPL in the right and left ear respectively, the mean lower and upper limit of the spectrum being 678 and 5720 Hz. According to these criteria 494/640 ears (77.2%) passed the test at the first recording, while TEOAEs resulted to be absent in 146/640 ears (22.8%). A retest was performed successfully before the discharge from the Hospital in 30/640 ears (4.7%). An ABR recording within the third month of life was scheduled as out-patient in the 58 new-borns (116 ears, 18.2%) who failed the test. 18 of them (36 ears, 5.6%) did not complete the program, 19 new-borns (38 ears, 11.8%) showed a normal ABR, while two new-borns (four ears, 0.6%) failed ABR after 3 months. A second ABR performed after 6 months was normal. CONCLUSIONS: TEOAEs recording seems at now the test of choice for a universal hearing screening. However, a greater standardization of criteria both in performing the test and in evaluating the results is needed.

Acoustic Stimulation↗
PubMed1999

Oncological and functional outcome of conservative surgery for primary supraglottic cancer.

The aim of this study was to verify the oncological and functional outcome of conservative surgical treatment of primary supraglottic squamous cell carcinoma (SGSCC) and related neck disease in order to verify the effectiveness of supraglottic laryngectomy (SL) and the validity of an "observation" policy in the control of clinically negative (N0) necks. Of a total of 252 consecutive patients affected by primary SGSCC seen between 1975 and 1990 at the Department of Otolaryngology of the University of Perugia (1975-1987) and the Catholic University of the Sacred Heart of Rome (1988-1990), a subset of 132 patients treated with classical SL was evaluated after presenting sufficient clinicopathological data and a follow-up period of at least 5 years. Tumors were staged according to the 1992 UICC TNM classification and grouped into stages I-II (n = 94) and III-IV (n = 38). Comprehensive neck dissections were performed only in the clinically positive (N+) necks (25/132 cases), while in the clinically N0 ones (107/132 cases) an "observation" policy under strict follow-up conditions was adopted. After primary surgery, the 5-year relapse-free survival (RFS) was 74%. The RFS was 80% for T1-2 disease and 65% for T3. The RFS was 80% for stages I-II tumors and 71% for stages III-IV. The actual 5-year overall survival (OS) was 89% for T1-T2 tumors and 67% for T3 disease or 93% for stage I-II and 69% for stages III-IV. The OS was 89% for N0 neck and 73% for N+. The 5-year-metastasis-free survival (MFS) was 83% for N0 patients, 74% for N+, 84% for T1-T2 N0, 71% for T1-T2 N+, 81% for T3 N0 and 68% for T3 N+. In all, SL was found to be highly effective in the management of primary SGSCC. In the presence of clinically N0 neck "observation" under strict follow-up with therapeutic comprehensive neck dissection for delayed nodal recurrence, SL was suitable for controlling the neck cancer, as well as for salvaging recurrent disease. Bilateral elective, selective or functional neck dissection in every instance of supraglottic cancer was best performed only in those SGSCC patients who were more likely to have occult nodal disease on the basis of biological factors and imaging data.

Actuarial Analysis↗
PubMed1999

CO2 laser subtotal arytenoidectomy and posterior true and false cordotomy in the treatment of post-thyroidectomy bilateral laryngeal fixation in adduction.

A total of 39 patients with bilateral post-thyroidectomy vocal cord paralysis in adduction underwent CO2 laser subtotal arytenoidectomies with removal of the posterior third of the false and true vocal cords. Total airway resistance (Rtot) evaluated before and 4-10 months after surgery showed marked preoperative impairment before and significant improvement after surgery (P < 0.05). In five patients revision surgery was performed due to a progressive impairment of respiratory function. A variable degree of voice breathiness was observed after surgery; the maximum phonation time mean values were lower than normal and peak sound pressure levels 63 +/- 5 dB. In three cases aspiration was present in the first postoperative days, but swallowing dysfunctions disappeared within 1 week. Subtotal arytenoidectomy with removal of the posterior third of the true and false vocal folds was found to be a satisfactory surgical treatment for bilateral vocal cord paralysis in adduction. However, further research is still needed to define the surgical procedure able to balance respiratory, phonatory and sphincteric functions optimally.

Adult↗
PubMed1999

An unusual complication of cochlear implant: benign paroxysmal positional vertigo.

Three days after the initial fitting of the cochlear device a 40-year-old woman complained of severe rotational vertigo following head movements associated with neurovegetative symptoms. Otoneurological evaluation revealed a horizontal paroxysmal positional nystagmus beating towards the lowermost ear, induced by rolling the patient's head from supine both to the right or to the left lateral position suggesting the diagnosis of benign paroxysmal positional vertigo of the left horizontal semicircular canal. The nystagmus characteristics were the same whether the cochlear device was switched on or off. The hypothesis of an otolith dislodging due to the electrical stimulation during the initial fitting is discussed.

Adult↗
PubMed1999

Scintigraphic assessment of swallowing after horizontal supraglottic laryngectomy.

OBJECTIVE: Oral-pharyngo-esophageal scintigraphy (OPES) proved to be able to demonstrate the pharyngeal residue of the radioactive bolus after deglutition and the presence and amount of tracheobronchial aspiration, and to calculate exactly the transit time of the various swallowing phases. The aim of this study was to evaluate the real objective effectiveness of OPES in order to assess the degree of swallowing recovery after horizontal supraglottic laryngectomy (HSL). METHODS: Nineteen patients entered the study, and 17 healthy subjects were included as control group (group 1). Nineteen patients in whom HSL had been performed at least 1 year before underwent OPES. They were divided into two groups: 13 patients (group 2) in whom the tracheal cannula had been removed and swallowing, phonatory, and respiratory functions were satisfactory and 6 patients (group 3) in whom the tracheostomy tube was still in situ for aspiration of liquids and scarring of the laryngeal vestibule. RESULTS: Our results showed that in the patients who underwent HSL, all scintigraphic semiquantitative parameters and particularly aspiration percentage values and Pharyngeal Ritention Index (PRI) at 10 and 60 seconds were able to pinpoint some residual "subclinical" alteration and/or minimal surgical sequelae frequently observed after this kind of functional surgery, even though a substantially satisfactory recovery was achieved clinically (group 2 versus group 1). In addition, aspiration amounts in group 3 were markedly higher than those in group 2 (p < .0002), and mean PRI values at 10 and 60 seconds were significantly different (p < .0001) from normal mean control values (group 1). CONCLUSION: Oral-pharyngo-esophageal scintigraphy may be regarded as a noninvasive, well-tolerated technique, with a radiation body burden within satisfactory limits of radioprotection. It appeared to be also sensitive in assessing the swallowing recovery after HSL.

Adult↗
PubMed1998

Relationship between chronic nasal obstruction and craniofacial growth: an experimental model.

The aim of this paper was to verify if the growth of the nasomaxillary complex can be influenced by a purely functional alteration such as nasal obstruction, which was induced experimentally in a genetically controlled animal model. Sixty albino rats were employed. Twenty of them had the right nostril occluded by a synthetic resin; another twenty had both nostrils occluded; the other 20 were taken as control group. When the growth was completed, the rats were sacrificed and cephalometric analysis was carried out. Both treated groups showed a statistically significant reduction in overall weight and height, in the vertical development of the nasomaxillary complex and in the skullbase longitudinal axis. After discussing the literature on the subject, the authors conclude that normal craniofacial growth in the rat must somehow depend on physiological nasal breathing, which should therefore be considered of crucial importance.

Animals↗
PubMed1998

Postural control in benign paroxysmal positional vertigo before and after recovery.

Thirty-two patients affected by idiopathic benign paroxysmal positional vertigo (BPPV) of the posterior semicircular canal were studied before, 3 days and I month after a resolutive Semont manoeuvre by means of dynamic posturography. The overall postural control in BPPV patients was shown to be impaired, as demonstrated by the pathological equilibrium scores. Data obtained before treatment showed a specific pattern of vestibular involvement and a pathological composite score. After the liberatory manoeuvre the Sensory Organization Test indicated a significant improvement in the pathological composite and vestibular scores. However, significant differences from controls were still detected 3 days and 1 month after clinical recovery from BPPV. The results clearly show that, in BPPV patients, there is an impairment of the vestibular system, which seems unable to maintain a normal postural balance. This deficit can be particularly detected when dynamic posturography evaluates the vestibular cues. After the liberatory manoeuvre a consistent improvement in the overall postural control has been observed but the residual differences from controls seem to suggest that damage to the otoconial maculae influences postural control, even when there is significant improvement in the clinical signs.

Analysis of Variance↗
PubMed1998

Growth inhibition of fibroblasts from nasal polyps and normal skin by lysine acetylsalicylate.

Some authors have shown that lysine acetylsalicylate (LAS) may help prevent nasal polyp relapses. As some anti-inflammatory drugs have been found to regulate cell growth, we investigated the antiproliferative effect of LAS on fibroblasts derived from nasal polyps. Moreover, we studied the effect of LAS on the growth of fibroblasts derived from normal skin to determine whether the response was similar to that obtained in the above-mentioned cells. Fibroblasts were obtained from tissue samples of nasal polyps from two aspirin-tolerant and two aspirin-intolerant patients, and from the normal skin of a healthy donor. The cells were treated with LAS (20-2000 microg/ml of culture medium). Cell growth and viability were evaluated after 3 and 6 days of culture. LAS had a growth-inhibitory effect on cells independently of their derivation. A reduction in cell growth was seen at the concentrations of LAS tested, which correspond to those used in the local treatment of nasal polyposis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Distortion-product otoacoustic emissions and selective sensorineural loss in IDDM.

OBJECTIVE: To provide information about possible subclinical damage of the cochlear outer hair cells (OHCs) by means of transiently evoked otoacoustic emissions (TEOAEs) and distortion-product otoacoustic emissions (DPOAEs) in subjects with IDDM. RESEARCH DESIGN AND METHODS: TEOAEs and DPOAEs were recorded in 47 IDDM patients with normal hearing and in age- and sex-matched nondiabetic subjects. Peripheral neuropathy was diagnosed by nerve conduction velocity (NCV) at the peroneal and surral nerves. RESULTS: A subclinical peripheral neuropathy was found in 15 diabetic patients. Mean TEOAE amplitude was found to be significantly reduced in diabetic patients with a reduced NCV (7.6 +/- 3.2 dB; Scheffé's test: P = 0.03), but not in those without neuropathy (9.5 +/- 4.3 dB), with respect to control subjects (11 +/- 3.1 dB). Neuropathic patients also showed mean reduced DPOAE amplitude values in the region of middle and high frequencies from 1,306 to 5,200 Hz (P < 0.05), whereas no difference was found at the lowest-frequency amplitudes. A frequency-selective reduction of DPOAEs was also found in non-neuropathic patients (P < 0.05) in the region of higher frequencies at 3,284, 4,126, and 5,200 Hz compared with control subjects. No correlations were found among duration of diabetes, HbA1c values, TEOAEs and DPOAEs. CONCLUSIONS: Our results suggest that IDDM patients show an early abnormality of the micromechanical properties of the OHCs. In IDDM patients without a subclinical peripheral neuropathy, damage is limited to the higher frequencies and can be detected only by DPOAEs, whereas in IDDM patients with neuropathy, damage also involves the middle range of frequencies and can be detected by TEOAEs and DPOAEs. Therefore, DPOAEs seem to be able to detect the earliest cochlear selective-frequency dysfunction in IDDM patients without peripheral neuropathy. DPOAEs appear to be of greater clinical interest than TEOAEs; the former seem to be frequency specific and can be recorded at any chosen frequency, including high frequencies.

Acoustic Stimulation↗