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Biomedical subjects

F Ottaviani

Publications and source records attributed to F Ottaviani.

At least 73 records · Page 4Linked to original sources
PubMed1995

Generation of human auditory steady-state responses (SSRs). II: Addition of responses to individual stimuli.

In order to investigate the generation of the 40 Hz steady-state response (SSR), auditory potentials evoked by clicks were recorded in 16 healthy subjects in two stimulating conditions. Firstly, repetition rates of 7.9 and 40 Hz were used to obtain individual middle latency responses (MLRs) and 40 Hz-SSRs, respectively. In the second condition, eight click trains were presented at a 40 Hz repetition rate and an inter-train interval of 126 ms. We extracted from the whole train response: (1) the response-segment taking place after the last click of the train (last click response, LCR), (2) a modified LCR (mLCR) obtained by clearing the LCR from the amplitude enhancement due to the overlapping of the responses to the clicks preceding the last within the stimulus train. In comparison to MLRs, the most relevant feature of the evoked activity following the last click of the train (LCRs, mLCRs) was the appearance in the 50-110 ms latency range of one (in 11 subjects) or two (in 2 subjects) additional positive-negative deflections having the same periodicity as that of MLR waves. The grand average (GA) of the 40 Hz-SSRs was compared with three predictions synthesized by superimposing: (1) the GA of MLRs, (2) the GA of LCRs, (3) the GA of mLCRs. Both the MLR and mLCR predictions reproduced the recorded signal in amplitude while the LCR prediction amplitude resulted almost twice that of the 40 Hz-SSR. With regard to the phase, the MLR, LCR and mLCR closely predicted the recorded signal. Our findings confirm the effectiveness of the linear addition mechanism in the generation of the 40 Hz-SSR. However the responses to individual stimuli within the 40 Hz-SSR differ from MLRs because of additional periodic activity. These results suggest that phenomena related to the resonant frequency of the activated system may play a role in the mechanisms which interact to generate the 40 Hz-SSR.

Acoustic Stimulation↗
PubMed1995

[Oncogenes and cancer of the larynx. EGFR, p21 ras and HPV-DNA infections].

The modern concept of oncogenesis is based upon the interaction between factors which modulate cellular growth and differentiation, in particular oncogenes and tumor suppressor genes. The molecular events which induce laryngeal carcinogenesis are not yet known. Protoncogenes seem to be the target of the risk factors (cigarette smoking, alcohol abuse, ionizing radiations and, not least HPV-DNA) that are commonly considered related to laryngeal squamous cell carcinoma. New information on the role of alterations of oncogenes and/or their proteic products in laryngeal cancer will be useful in identifying new diagnostic and clinical therapeutical applications. The Authors investigated Epidermal Growth Factor Receptor (EGFR) expression in 103 primary laryngeal squamous cell carcinoma and 42 normal laryngeal tissue specimens in order to assess its clinical significance in primary laryngeal cancer. Significantly higher EGFR levels were found in cancer specimens compared with normal mucosa (p < 0.001). EGFR expression did not correlate with age, tumor localization, T classification, cervicallymphonode involvement or surgery, whereas in G3 tumors it was significantly higher than in G1-G2 (p < 0.05). Follow-up data were available for 74 cases: EGFR levels resulted significantly higher in patients who had a recurrence of the disease than those in recurrence-free patients (p < 0.05). The 24-month disease-free survival (DFS) was 58% for EGFR+ patients and 82% for EGFR-subjects. Multivariate analysis permitted identification of EGFR status and tumor localization as significant independent prognostic factors. Data reported here suggest that EGFR expression probably plays a role not only by regulating the growth of laryngeal cancer, but also by identifying a sub-set of laryngeal cancer patients at a higher degree of relapse risk and with an unfavorable prognosis. Furthermore, in this study p21-ras expression in 43 primary laryngeal cancers and in 7 normal laryngeal mucosa specimens was evaluated. Scattered p21 levels, expressed as optical density (O.D), were found in normal mucosa (median = 1.94) and in primary laryngeal tumours (median = 1.74). Higher p21 levels were found in neoplastic tissue than in normal laryngeal tissue (median = 2.54 vs median = 1.94; p = 0.023). The correlation between p21 ras protein and EGFR levels was also investigated. EGFR+ cases do not show any difference in p21 expression with respect to EGFR- cases (median = 1.52 O.D. vs median = 1.84). Our findings suggest that overexpression of p21 is associated with malignant phenotype in laryngeal cancer.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

[Phonorhinorheometric study and laryngeal sonography in subjects affected by velopharyngeal insufficiency].

The aim of the present study was to evaluate the validity of combining two non invasive diagnostic approaches, (photorhinorheometry and sonography) in order study phonatory pathology in subjects suffering from velopharyngeal insufficiency (VPI). Twenty-six patients with nasal air escape during phonation and/or hyperrhinophonia due to to VPI were evaluated employing both methods. Phonorhinorheometry permitted air escape through the nasal cavities during phonation to be evaluated. Compartmentalization of the pharyngeal and nasal resonators during phonation was measured through MCF (maximal consonantic flow) values and MCV (mean consonantic volume), both normalized to the intensity of sound emission during the consonatic phases of speech. Sonography gave information concerning the phonema of resonance and articulation: a modification of the method, which also permitted sound production through an electroacoustic transductor kept in contact with the prelaryngeal skin, was made. This reduced intrinsic noise and increased dynamic modulations of the resonators of the vocal tract. Comparison between sonographic recordings obtained through a standard microphone and skin transducer permitted evaluation of influence of the vocal tract above the glottis on the phonatory process. In particular, recordings had by skin transducers showed a wider amplitude display and a better identification of vocal attack. Phonorhinorheometry and sonography are useful objective and non-invasive tools in evaluating phonatory pathology in patients suffering from VPI and in monitoring therapeutic approaches.

Adolescent↗
PubMed1995

[Centro-peripheral etiopathogenesis of primary headache triggered nasally].

The presence of endonasal pathological conditions or headache accompanying symptoms involving the nose, show a bi-directional link between the latter and endocranial structures. Instrumental diagnostic procedures allow demonstration of anatomical variants of the bone. Frequently, surgical procedures addressed to correct such variants seem to resolve both headache and breathing disturbances. However, hyperactivity of nasal mucosa and microcirculation might be responsible for cephalic disturbance as a consequence of activation of neuro-vascular systems (trigeminal, sympathetic, parasympathetic) and explain both pain and attendant accompanying symptoms during migraine and cluster headache attacks. Peripheral triggering or aggravating factors may, therefore, be responsible for or, at least, contribute to pathophysiological mechanisms of certain headaches.

Animals↗
PubMed1993

Acoustic structure of vocalization and stapedius muscle activity during vocal development in chickens (Gallus gallus).

The link between stapedius muscle activity and acoustic structure of vocalization was analysed in cocks of age 20-30 to 90-100 days old. The results show that stapedius muscle activation depends on the acoustic structure of vocalization and changes during vocal development. This dependence was observed in spontaneous calls and in vocalizations elicited by stimulating the mesencephalic "calling area". In 30-day-old cocks stapedius muscle EMG response is never associated with vocalizations with an acoustic energy content which is always distributed at frequencies higher than 2000 Hz. The coupling between vocalization and stapedius muscle activity begins later, when birds produce vocalizations with acoustic energy shifted towards lower frequencies. Overall, stapedius muscle activity is related to a bird's production of high amplitude low frequencies. These results support the hypothesis that the primary role of the stapedius muscle during normal vocal development is to dampen the amplitude of low frequency energy that reaches the cochlea during vocalization.

Aging↗
PubMed1992

Innervation of the paralyzed laryngeal muscles by phrenic motoneurons. A quantitative study by light and electron microscopy.

In the cat, inspiratory opening of the paralyzed glottis recovered after unilateral or bilateral reinnervation of the posterior cricoarytenoid (PCA) muscles by phrenic axons. The morphometric analysis of the regenerated recurrent laryngeal nerves (RLNs), showed that proliferation was abundant; 4 months after the nerve anastomosis, more than 500 myelinated axonal branches repopulated the RLNs. The mean diameter of motor axons (3.5 to 5.0 microns) was lower than in normal phrenic and RLN (8 to 10 microns), and the mean internode length was about half that of the normal RLN. Histochemical examination of the PCA muscle revealed that muscle fiber composition (44% type I and 56% type II muscle fiber) was fairly similar to that of normal PCA. The contraction time of the reinnervated muscles was as long as 60 msec at the time of movement recovery, but it shortened to 25 to 30 msec when the reinnervation time increased. These anatomical and functional results support the choice of the phrenic nerve for laryngeal reinnervation.

Adenosine Triphosphatases↗
PubMed1991

Interference of cephalosporins with immune response: effects of cefonicid on human T-helper cells.

To determine the immunosuppressive effect(s) of cephalosporin cefonicid (CEFO) on human T-helper cells (Th), we exposed human peripheral blood mononuclear cells (PBMC) to various concentrations of CEFO during in vitro stimulation with a panel of T-lymphocyte stimulators that activate different Th/antigen presenting cell (APC) pathways. We evaluated the proliferation and IL-2 production induced by influenza virus (FLU), allogeneic lymphocytes (ALLO), xenogeneic mouse splenocytes (XENO) or phytohemagglutinin (PHA). The proliferative responses to FLU and XENO were much more depressed by CEFO than those to ALLO or PHA. After 7 days of culture with the highest dose of CEFO tested (200 mg/l) the stimulation index (stimulated/unstimulated culture) was near to 0 in FLU and XENO treated cultures, indicating that the response against these antigens was completely abrogated. The responses to ALLO and PHA were also impaired, but not abrogated (stimulation index greater than 1). Since FLU and XENO utilize the CD4+ Th/self-APC pathway our data suggested that this pathway was extremely sensitive to CEFO-induced inhibition both when the response requires memory Th cells (FLU) and virgin Th cells (XENO). The incubation with CEFO (200 mg/l) reduced the IL-2 production by XENO, FLU and ALLO to less than 20% of control cultures, while paradoxically increases to 120% the production by PHA.

Antigens↗
PubMed1990

Vocalization-related stapedius muscle activity in different age chickens (Gallus gallus), and its role in vocal development.

The stapedius muscle activity associated with vocalization was analyzed in young and adult roosters. Our results show that remarkable differences in the behavior of vocalization-related stapedius muscle activity exist between these two ages. Unlike young roosters, electrical stimulation in the midbrain of adult cocks yields vocalizations associated with stapedius muscle EMG responses that always show a higher threshold and a longer latency than those of the vocalization induced. Moreover, the maximal amplitude of the stapedius muscle EMG response is consistently lower than that detected in young roosters, despite the fact that the maximal vocalization amplitude of the adult birds is much higher. On the whole our results demonstrate that vocalization-related stapedius muscle activity is strongly reduced in adulthood. The possibility that stapedius muscle may play a role during the vocal development was verified by comparing the crow of normal roosters with that of cocks from which the stapedius muscle had been removed shortly after hatching. Strong differences exist in the amplitude/frequency distribution of the crowing of normal and stapedectomized roosters, suggesting that the stapedius muscle exerts an important role in auditory feedback modulation, and that this feedback is used for normal vocal development.

Aging↗
PubMed1990

Marijuana smoking as a possible cause of tongue carcinoma in young patients.

A case of T1N0M0 carcinoma of the tongue in a male 23-year-old 'regular' marijuana smoker is described. Hemiglossectomy and complete bilateral neck dissection were carried out. No post-operative radiotherapy was given as the resection margins were histologically negative. The tumour recurred one year later in the left cervical region involving the mandible and surgery was again performed, but after three months, neck disease was still evident. The case described case implies the introduction of marijuana as a possible new risk factor in the development of oral cavity tumours. Resection of the primary lesion has to be as wide as possible even in T1 cases, due to the aggressive biological behaviour of such tumours in young subjects.

Adult↗
PubMed1990

Auditory brainstem responses in the aged.

The auditory brainstem responses (ABR) in a group of 74 aged subjects (60-80 years), affected by presbycusis were evaluated for presence of a retrocochlear involvement. The comparison of results from subjects with presbycusis with those from normally-hearing elderly subjects, and young subjects, affected by a cochlear sloping hearing loss, revealed that the latency increase of ABR observed in presbycusis is mainly correlated to the audiometric shape of the hearing loss and not to age per se.

Acoustic Impedance Tests↗
PubMed1990

Auditory steady-state responses in the rabbit.

The authors have studied auditory brainstem (ABRs), middle latency (MLRs) and steady-state potentials (SSRs) in 15 adult male rabbits weighing between 2.5 and 3 kg in order to verify if SSRs are due to a mere superimposition of ABRs and MLRs or to a resonance phenomenon. Ten of them were awake while 5 were studied under urethane anesthesia. Acoustic stimuli consisted in 0.1-ms square-wave pulses delivered at presentation rates ranging between 1 and 80/s at a stimulus intensity of 80 dB p.e. SPL. Our data show that reliable auditory SSRs can be obtained in the rabbit at a presentation rate of 30 stimuli/s, probably due to the superimposition of ABRs and MLR Pb waves which show an interwave interval of about 35 ms. The nonlinear aspects which can be detected are probably due to the effect of decreasing interstimulus intervals on the duration and amplitude of the Pb wave. It can then be concluded that SSRs in the rabbit are due more to a superimposition of ABR and MLR waves than to a resonance phenomenon.

Acoustic Stimulation↗
PubMed1990

40-Hz steady-state responses in newborns and in children.

The authors investigated the 40-Hz steady-state responses (SSR) in 32 full-term newborns and in 10 normal children (5-8 years old), using 500-Hz tone bursts. The 40-Hz SSR threshold is located at about 50 and 30 dB nHL in newborns and older children, respectively. The latencies of both P1 and N1 waves decreased significantly with age, while the amplitudes increased. No significant latency and amplitude intersex differences have been observed. Moreover, with age, the 40-Hz SSR became more stable, their test-retest replicability improved, and P1-N1 wave occurrence increased. The authors finally discuss the possible underlying mechanisms of these findings and conclude that the 40-Hz SSR are difficult to obtain and are scarcely reliable in defining the low-frequency threshold in newborns. The stability and reliability of the responses increase with age, and the electrophysiological and behavioral thresholds to low-frequency stimuli tend to overlap.

Audiometry, Evoked Response↗
PubMed1989

Vocalization and stapedius muscle activity evoked by local electrical stimulation of midbrain in the chicken (Gallus gallus).

The organization of chicken mesencephalic areas from which stapedius muscle activity and vocalization can be differently elicited was studied. Our results show the existence of an area, around the mesencephalic 'calling area', from which stapedius muscle activity can be evoked independently of vocalization. Furthermore, low threshold 'vocalization loci' stimulation evokes field potentials in the stapedius-controlling area, due to the activation of stapedius-controlling neurons by vocalization neurons.

Animals↗
PubMed1989

Recovery of inspiratory abduction of the paralyzed vocal cords after bilateral reinnervation of the cricoarytenoid muscles by one single branch of the phrenic nerve.

The aim of this study was to provide the bilateral reinnervation of the posterior cricoarytenoid (PCA) muscles by the superior root of the right phrenic nerve. In six adult cats, the right phrenic root was anastomosed to the distal stump of the transected recurrent laryngeal nerve (RLN) on the same side. The RLN adductor branch was then cut and anastomosed to a nerve graft whose end was carried contralaterally and sutured to the left RLN or to the left PCA muscle. The phrenic fibers regrowing along the RLN abductor branch reinnervated the right PCA muscle and restored the inspiratory abduction of the right vocal cord in all the animals. In five of the six cats, the fibers regenerated through the RLN adductor branch and the graft reached the left PCA muscle and also restored the inspiratory opening of the larynx on the left side. Histological nerve examination revealed a fairly symmetrical distribution of the regenerated phrenic axons to the right and left PCA muscles.

Anastomosis, Surgical↗
PubMed1988

Auditory brainstem responses in noise-induced permanent hearing loss.

Fifty-four patients (108 ears) with presumed noise-induced hearing loss, were subjected to tonal and speech audiometry, impedance tests and measurements of auditory brainstem responses (ABR), in order to check for possible retrocochlear involvement. ABR data indicated that latency values of waves I, III and V, as well as III-I, V-III and V-I intervals fell within the normal range in all cases (M +/- 2 SD), even for fast repetition rates (51 stim/s). Poor waveform resolution of early components, particularly of wave I, was found in 12 ears (11.1%) and a total absence of evoked potentials not always related to the hearing loss, occurred in 5 ears (4.6%).

Acoustic Impedance Tests↗