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Biomedical subjects

G Paludetti

Publications and source records attributed to G Paludetti.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Otogenic cerebral abscess: description of 3 cases, clinical and therapeutic considerations].

The authors use the 3 cases of otogenous cerebral abscess which came under observation as starting point for a discussion of the main etiopathogenetic, microbiological, clinical-diagnostic and therapeutic aspects of this disorder. After a brief presentation of the data regarding incidence, preferential localization and age of onset, they discuss the means for intracranial spread of infection and the related symptoms. As regards diagnosis, the authors assert that clinical examination and imaging techniques--CT and especially MRI--enable one to determine the dimension and site of the abscess cavity, differentiating it from other intracranial lesions and to monitor clinical evolution and response to therapy. After mentioning the principle bacteria involved in infection, they deal with the various means of treatment. The authors favor surgical removal of the auricular phlogistic focus and medical treatment of the intracranial abscess. They resort to neurosurgery only in those cases which do not respond to drug treatment or when the size and particular location of the abscess threaten the patient's life. In conclusion, the authors underline the problems seen today in diagnosis and therapy, comparing the quoad vitam and quoad valetudinem prognosis for the affected patients.

Adolescent↗
PubMed1998

[Functional results after cordectomy in laryngeal fissure and in microlaryngoscopy with CO2 laser].

Videolaryngostroboscopy, psychoacoustic and spectrographic analyses were performed to evaluate vocal function in two groups of male patients who had undergone CO2Laser (n = 23) and laryngofissure cordectomy (n = 21) for the treatment of T1a glottic carcinoma. None of the patients used their voices professionally. This study revealed a good correlation between the anatomical features and voice quality. Psychoacoustic and spectrographic analysis showed that the functional results were significantly worse in the patients treated by laryngofissure (p < 0.003). In this group videolaryngostroboscopy showed a higher rate of compensation in both ventricular folds than shown in the laser-treated group (p < 0.02). The authors conclude that the functional results obtained after cordectomy depend on the various combinations of scarring patterns and compensatory hyperkinesia of the ventricular or vocal folds. The better anatomical and functional results achieved following laser cordectomy may be explained by the fact that such procedures result in better, more rapid healing processes.

Aged↗
PubMed1997

The contribution of immunoscintigraphy to the diagnosis of head and neck tumours.

Immunoscintigraphy with 111In-F(ab')2-anti-carcinoembryonic-antigen monoclonal antibody was performed in patients with primary head and neck tumours (n = 14), recurrences (n = 3) and suspected posttherapy lymph node metastases (n = 3). No false-positive but two false-negative results were obtained. Single photon emission tomography was performed 24 h after the intravenous administration of the radiopharmaceutical with a positive predictive value of 100% and a sensitivity of 90%. Only two very small (< 1 mm diameter) and necrotic primary tumours escaped detection, while the recurrences and lymph node metastases were always correctly diagnosed, in contrast to computerized tomography and ultrasound. Even though highly selective patients only were considered in the present research, the results do suggest that immunoscintigraphy may be usefully applied in all routine protocols for the study of head and neck cancer.

Aged↗
PubMed1997

Cochlear dysfunction in IDDM patients with subclinical peripheral neuropathy.

OBJECTIVE: To investigate the function of the auditory pathway from the cochlea to the auditory cortex in subjects with IDDM. RESEARCH DESIGN AND METHODS: Brain stem, middle-, and long-latency auditory-evoked responses and evoked otoacoustic emissions were measured in 48 normally hearing IDDM patients and in age- and sex-matched nondiabetic subjects. Peripheral neuropathy was diagnosed by nerve conduction velocity (NCV) at the peroneal and sural nerves. Auditory brain stem responses (ABRs) reflect auditory pathway function within the brain stem; middle-latency responses (MLRs) and long-latency responses (LLRs) originate from the auditory cortex; and evoked otoacoustic emissions (EOAEs) give objective information about preneural, mechanical elements of the cochlear function. RESULTS: A subclinical peripheral neuropathy was found in 12 diabetic patients. We found higher latencies of waves I (t = 4.4, P < 0.0001), III (t = 3.7, P = 0.0004), and V (t = 2.7, P = 0.008) of ABRs in diabetic patients (I: 1.7 +/- 0.13 ms; III: 3.9 +/- 0.17 ms; V: 5.7 +/- 0.24 ms), compared with those of the control group (I: 1.6 +/- 0.13 ms; III: 3.7 +/- 0.18 ms; V: 5.6 +/- 0.17 ms). However, neither central transmission time (i.e., the wave interpeak I-V) nor MLRs and LLRs were found to be significantly different in diabetic and control subjects. Mean EOAE amplitude was found to be significantly reduced (F = 4.2, P = 0.02) in diabetic patients with a reduced NCV (7.6 +/- 3.9 dB; Scheffé test: P = 0.03), but not in those without neuropathy (9.1 +/- 4.2 dB), compared with the control group (10.8 +/- 3.1 dB). No correlations were found between duration of diabetes and EOAEs or between sural NCV and peroneal NCV and metabolic control. EOAEs were not correlated with peroneal and sural NCVs. CONCLUSIONS: Our results indicate that the early preneural dysfunction of cochlear receptors causes a prolonged activation of the peripheral portion of the auditory pathway, while signal conduction along the central auditory pathway was shown to be normal in diabetes.

Adult↗
PubMed1997

Glycosaminoglycan metabolism and cytokine release in normal and otosclerotic human bone cells interleukin-1 treated.

Glycosaminoglycans (GAGs), normal components of the extracellular matrix (ECM), and the glycosidases, that degrade them, play a key role in the bone remodelling process. The effects of interleukin-1 alpha (IL-1 alpha) on GAG metabolism in normal and otosclerotic human bone cells as well as its capacity to modulate IL-1 alpha, IL-1 beta and IL-6 secretion in both populations was analyzed. The amount of radiolabeled GAGs was lower in otosclerotic than in normal bone cells. IL-1 alpha reduced newly synthesized cellular and extracellular GAGs in normal cells, but only those of the cellular compartment in otosclerotic bone cells. It depressed heparan sulphate (HS) more in normal cells and chondroitin sulphate (CS) more in otosclerotic bone cells. The HA/total sulphated GAG ratio was shifted in favour of the latter in otosclerotic cells, whereas the opposite effect was seen after IL-1 alpha treatment. There was little difference in the beta-D-glucuronidase levels of the normal and pathological cells, while beta-N-acetyl-D-glucosaminidase was significantly increased in otosclerotic bone cells. As the activity of neither enzyme was modified by treatment with IL-1 alpha, the cytokine seems to exert its influences on GAG synthesis rather than on the degradation process. IL-1 alpha, IL-1 beta and IL-6 secretion was markedly higher in otosclerotic cells. IL-1 alpha modulated the secretion of each interleukin differently, thus resulting in a cytokine cascade that may act in autocrine/paracrine manner on target cells. The authors suggest that changes in the cytokine network may have a specific, yet still unknown, role during normal and pathological osteogenesis.

Bone and Bones↗
PubMed1996

Cathepsin D concentration in primary laryngeal cancer: correlation with clinico-pathological parameters, EGFR status and prognosis.

Sixty-three patients with primary laryngeal squamous-cell carcinoma were followed up for a median of 33 months after surgery. Cathepsin D (Cath D) concentration was assayed using a solid phase 2-site immunoradiometric assay in which the first monoclonal antibody (MAb) was coated on the ELISA solid phase and the second one, MIG8 radiolabeled with 1125-EGF, was used as the tracer. The median value of Cath D (13.8 pM/mg protein) was chosen as cut-off. Cath D > or = median value was closely related to neck lymph node involvement at presentation and to a short metastasis-free survival (MFS) and actual overall survival (OS). The 5-year MFS was 71% for patients with Cath D < median value tumors as compared with 0% for patients with Cath D > or = median value tumors. Lymph node status at presentation was not related to a short MFS and OS. Cox's univariate regression analysis using Cath D as a continuous variable showed that Cath D levels are correlated with neck lymph node metastasis. On multivariate analysis, Cath D status proved to be an independent factor for predicting a short MFS. Cath D assay may prove to be particularly useful in identifying laryngeal cancer patients who, with or without neck lymph node involvement at presentation, are at high risk of metastatic disease and poor outcome.

Carcinoma, Squamous Cell↗
PubMed1996

Detection of human papillomavirus DNA in laryngeal squamous cell carcinoma by polymerase chain reaction.

Although human papillomaviruses (HPVs) have been found in many, but not all, tumours of the oral cavity, nose, pharynx and larynx, the true role of HPV in malignant tumours of the head and neck is still unclear. The presence of HPV DNA was investigated in 45 fresh squamous cell carcinoma (SCC) specimens and in 29 normal mucosa specimens collected from 45 primary laryngeal SCC patients. HPV DNA was detected using the polymerase chain reaction (PCR) with consensus primers that detect HPV types 6, 11, 16 and 18.9 of the 45 patients (20%) were HPV positive; the presence of HPV was also detected in the corresponding normal laryngeal mucosa of four of the 29 specimens (14%). No statistically significant differences were found between the presence of HPV DNA in normal specimens and in neoplastic mucosa specimens. No correlation was found between HPV DNA positive tumours and size, T classification, lymph node involvement and histological grading. This study adds further evidence suggesting a possible role of HPV DNA infection in laryngeal carcinogenesis.

Adult↗
PubMed1996

Prognostic significance of epidermal growth factor receptor in laryngeal squamous cell carcinoma.

Epidermal growth factor receptor (EGFR) content was determined by a radioligand receptor assay in 140 primary laryngeal squamous cell carcinomas (median value of 8.4 fmol mg-1 protein, range 0-169.9 fmol mg-1 protein). Cox univariate regression analysis using EGFR as a continuous variable showed that EGFR levels are directly associated with the risk of death (chi 2 = 14.56, P-value = 0.0001) and relapse (chi 2 = 7.77, P-value = 0.0053). A significant relationship between EGFR status and survival was observed at the different arbitrary cut-off values chosen (8, 16 and 20 fmol mg-1 protein). The cut-off value of 20 fmol mg-1 protein was the best prognostic discriminator. In fact, the 5 year survival was 81% for patients with EGFR- tumours compared with 25% for patients with EGFR+ tumours (P < 0.0001). The 5 year relapse-free survival was 77% for patients with EGFR- tumours compared with 24% for patients with EGFR+ tumours (P < 0.010). When clinicopathological parameters and EGFR status were examined in the multivariate analysis, T classification and EGFR status retained an independent prognostic value. In this study we demonstrated that high EGFR levels single out patients with poor prognosis in laryngeal cancer.

Carcinoma, Squamous Cell↗
PubMed1996

Glycosaminoglycan metabolism in otosclerotic bone cells.

Normal and otosclerotic bone cells were cultured in vitro in serum-free medium to evaluate single glycosaminoglycan (GAG) class synthesis and secretion. Moreover, the degradative process was studied by inhibiting the lysosomal functions through the addition of ammonium chloride to the cultures, an ammine known to inhibit lysosomal degradation by neutralizing organelle activity. Otosclerotic bone cells accumulated a lower amount of GAG both in the cellular and extracellular pool compared to normal ones. The decrease was markedly higher for secreted GAG. Moreover a different pattern of single GAG class distribution was observed in the two cell types considered. In the medium of otosclerotic cells a percentage increase of hyaluronic acid (HA) and dermatan sulphate (DS) and a percentage decrease of heparan sulfate (HS) and chondroitin sulfate (CS) were observed compared to normal bone cells. Ammonium chloride had a lower effect on pathologic than on normal cells, indicating a decrease in the degradative process in otosclerotic bone cells. These results were also confirmed by the experiments on GAG uptake and degradation and by the dosage of enzymatic activity of two exoglycosidases. Since extracellular GAG composition influences bone deposition and mineralization, these data support the hypothesis that otosclerosis is the result of an error in the connective tissue matrix structure.

Acetylglucosaminidase↗
PubMed1996

SPET monitoring of perfusion changes in auditory cortex following mono- and multi-frequency stimuli.

AIM: In order to assess the relationship between auditory cortex perfusion and the frequency of acoustic stimuli, twenty normally-hearing subjects underwent cerebral SPET. METHODS: In 10 patients a multi-frequency stimulus (250-4000 Hz at 40 dB SL) was delivered, while 10 subjects were stimulated with a 500 Hz pure tone at 40 dB SL. The prestimulation SPET was subtracted from poststimulation study and auditory cortex activation was expressed as percent increments. RESULTS: Contralateral cortex was the most active area with multi-frequency and monofrequency stimuli as well. A clear demonstration of a tonotopic distribution of acoustic stimuli in the auditory cortex was achieved. In addition, the accessory role played by homolateral acoustic areas was confirmed. CONCLUSION: The results of the present research support the hypothesis that brain SPET may be useful to obtain semi-quantitative reliable information on low frequency auditory level in profoundly deaf patients. This may be achieved comparing the extension of the cortical areas activated by high-intensity multifrequency stimuli.

Acoustic Stimulation↗
PubMed1996

[Physiopathology of otosclerosis. Preliminary research].

The Authors report their personal data based on several studies carried out on cellular cultures of otosclerotic bones in order to clarify some pathogenetic aspects of the disease. Besides structural differences observed on the cytoskeleton, and some components of extracellular matrix (GAGs) of otosclerotic cells, the most interesting data arise from the different responses to hormonal stimulations using calcitonin, parathormone, steroid hormones and interleukin-1. This research leads the Authors to believe that transduction mechanisms in otosclerotic cells could be altered as a result of genetically induced receptorial changes, which become more evident after certain pathological events.

Humans↗
PubMed1996

[An oropharyngeal-esophageal scintigraphic study of deglutition].

The aim of the present work was to evaluate whether oro-pharyngeal-esophageal scintigraphy could be used in the dynamic study of the various phases of deglutition and to determine whether it could be applied in otorhinolaryngological practice along with videofluoroscopy and videoendoscopy. The patients were divided into four different groups according to clinical features and the scintigraphic data were analyzed on this basis. Emphasis is placed on the ease of this technique, its tolerability and the low level of radiation. It is pointed out that scintigraphy is quite useful in determinating the exact percentage of the bolus inhaled into the trachealbronchial branch and in measuring the transit time of the various phases of deglutition in detail. In patients affected by upper airway-digestive tract neoplasms it is, therefore, possible to make a semiquantitative evaluation of the results of surgery. Moreover, with this method the results of any rehabilitation can be measured as well as the onset of compensation mechanisms.

Aged↗
PubMed1995

Generation of human auditory steady-state responses (SSRs). I: Stimulus rate effects.

Auditory evoked responses were recorded in 16 normally hearing subjects in order to investigate the mechanisms underlying the generation of the 40 Hz steady-state response (SSR). In the first part of our study, auditory potentials were evoked by 0.1 ms clicks presented at 105 dB p.e. SPL with repetition rates of 7.9 (to obtain middle latency response, MLR), 20, 30, 40, 50, 60 Hz. In each subject predictions of the responses recorded at stimulus repetition rates of 30, 40, 50, 60 Hz were synthesized by superimposing MLRs at suitable time intervals. The calculated mean amplitude/rate and phase/rate functions behaved similarly for the recorded and predicted curves, showing the highest amplitude at 40 Hz and a linear increase of phase values when increasing the stimulus rate. Nevertheless the synthetic curves closely predicted amplitude and phase values of the recorded responses only at 40 Hz. At frequencies below 40 Hz, the mean amplitude of the predicted curve was lower than that of the recorded one while at frequencies above 40 Hz the mean amplitude was higher. Predicted phase values were found lagging at 30 Hz, and leading at 50 Hz and 60 Hz in comparison to phase values calculated on the recorded responses. Our findings suggest that a model based on the linear addition of transient MLRs is not able to adequately predict steady-state responses at stimulus rates other than at 40 Hz. Other mechanisms related to the recovery cycle of the activated system come into play in the steady-state response generation causing a decrease in amplitude and an increase in phase lag when increasing the stimulus repetition rate.

Acoustic Stimulation↗
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

Nasal obstruction and skull base development: experimental study in the rat.

The influence of nasal obstruction on the development of the anterior skull base, of the tympanic bulla, and of the Eustachian tube was investigated in three groups of 20 albino Wistar rats in which one (group B) or both nostrils (group C) had been experimentally obstructed by means of synthetic resin mixed with radiopaque material. After two months, a cephalometric investigation demonstrated that the angle formed by the median line passing through the superior interincisive point and the most posterior median point of the occipital bone and by the line connecting the tympanic bulla and the superior interincisive point was significantly increased when the homolateral nostril had been obstructed if compared to controls (group A). On the basis of these preliminary cephalometric observations we suggest that nasal obstruction is able to determine anatomical changes of the superior maxilla, the skull base, and the jaw, with abnormal skeletal growth and consequent possible Eustachian tube dysfunction.

Animals↗