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A number of studies have shown that cisplatin and gentamicin ototoxic effects may result from free radical-mediated damage due to the reduction of antioxidant substances and an increased lipid peroxidation. The authors summarize the results obtained evaluating the auditory and vestibular functions and the inner ear hair cell morphology and survival after administration of antioxidant agents against cisplatin and gentamicin. In the first experiment, albino guinea pigs were treated with gentamicin (100 mg/kg per day, i.m.) alone or gentamicin (100 mg/kg per day, i.m.) plus α-tocopherol (100 mg/kg per day, i.m.) for 2 weeks. In a second experiment, albino guinea pigs were injected with cisplatin (2.5 mg/kg per day) or cisplatin (2.5 mg/kg per day) plus tiopronin (300 mg/kg) for 6 days. Electrocochleographic recordings were made from an implanted round window electrode. In all experiments compound action potentials (CAPs) were measured at 2-16 kHz. Changes in cochlear function were characterized as CAP threshold shifts. To evaluate vestibular function, the animals underwent sinusoidal oscillations in the dark about their vertical and longitudinal axes to evoke horizontal and vertical vestibulo-ocular reflexes (VOR). Frequency stimulation parameters ranged from 0.02 to 0.4 Hz and peak-to-peak amplitude was 20°. Morphological changes were analysed by light microscopy and scanning electron microscopy. Both hearing loss and vestibular dysfunction induced by gentamicin were significantly attenuated by α-tocopherol. However, tiopronin co-therapy slowed the progression of hearing loss in cisplatin-treated animals and significantly attenuated the final threshold shifts. Cisplatin had little effect on the hair cells of cristae ampullares and maculae. Vestibular function was completely preserved in tiopronin co-treated animals. In conclusion, antioxidants such as α-tocopherol or tiopronin interfere with gentamicin and cisplatin damage and this suggests that they may be useful in preventing oto-vestibulotoxicity. Therefore, it is important to develop protective strategies that permit the avoidance of the toxic side effects of these drugs without interfering with their therapeutic effects. [ABSTRACT FROM AUTHOR]

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 stages 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In E. coli, protein degradation plays important roles in regulating the levels of specific proteins and in eliminating damaged or abnormal proteins. E. coli possess a very large number of proteolytic enzymes distributed in the cytoplasm, the inner membrane, and the periplasm, but, with few exceptions, the physiological functions of these proteases are not known. More than 90% of the protein degradation occurring in the cytoplasm is energy-dependent, but the activities of most E. coli proteases in vitro are not energy-dependent. Two ATP-dependent proteases, Lon and Clp, are responsible for 70-80% of the energy-dependent degradation of proteins in vivo. In vitro studies with Lon and Clp indicate that both proteases directly interact with substrates for degradation. ATP functions as an allosteric effector promoting an active conformation of the proteases, and ATP hydrolysis is required for rapid catalytic turnover of peptide bond cleavage in proteins. Lon and Clp show virtually no homology at the amino acid level, and thus it appears that at least two families of ATP-dependent proteases have evolved independently. [ABSTRACT FROM AUTHOR]

Morphology and calcium metabolism have been studied on five different cell cultures from human normal adult temporal-bone biopsies obtained during five stapedectomies. Control cell cultures were obtained from normal human skin. Four different cell types were observed in the bone biopsies: 1) osteoblast-like cells; 2) osteoclast-like cells; 3) fibroblast-like cells; 4) intermediate cells. However, morphology by itself is inadequate for clear differentiation of the four cell types. Hormonal stimulation with calcitonin and dibutyryl-cAMP in presence of Ca showed a clear-cut difference in Ca uptake between cultured cells deriving from bone and skin. Functional responses to hormonal stimulation are therefore more specific than cell shape and morphology in differentiating fibroblasts from bone cells. Since responses to hormonal stimulation confirm that temporal-bone cell cultures actually contain bone cells, such cultures seem to be a good experimental model for the study of bone morphology and physiology. [ABSTRACT FROM AUTHOR]

This paper reports the results of the EBV-specific antibody response in 17 Italian nasopharyngeal carcinoma (NPC) patients, 15 other head and neck tumor patients and 15 normal controls. Nucleic acid hybridization has been performed on the biopsy tissue from 4 of the NPC patients, and EBV-DNA was present in two undifferentiated (WHO 3) tumors, and absent in two samples of the keratinizing (WHO 1) type. EBV serology appears to be specifically related to NPC, more evidently for VCA-IgA and EA-IgG antibodies, and useful as an aid in diagnosis of NPC. However, in order to assess a prognostic value of the above markers, a greater number of patients followed for a longer period of time (at least 5 years) is needed, and is currently being pursued. [ABSTRACT FROM AUTHOR]

The clinical findings, histopathology, management and outcome of 31 patients with verrucous squamous cell carcinoma of the larynx (VSCC) are discussed. Laryngeal VSCC is a rare, highly differentiated variant of SCC and has specific morphological features and clinical behavior. A close liaison between the laryngologist and pathologist is needed to formulate a correct diagnosis, because this tumor appears to be malignant clinically and histologically benign. A low-power magnification of multiple large specimens, including the deep margins of the lesion, is required in order to differentiate VSCC from keratosis, verruca vulgaris or SCC with verrucous appearance, and to detect underlying microscopic foci of invasive SCC within or adjacent to a verrucous carcinoma. Long-lasting hoarseness was the most common symptom as the glottic region was the most common site of VSCC. Presumed clinically positive N1 lymph nodes were observed in the necks of 7 patients, but none had metastatic disease on histopathological study. Surgery alone was the most effective form of treatment, as it allowed a good outcome of all treated patients. Surgery plus radiotherapy was associated with an early recurrence and a poor outcome in 2 of 7 patients treated. The generally 'benign' behavior of VSCC allows for conservative surgery, with complete endoscopic resection using the carbon dioxide laser representing a more conservative surgical approach. Neck dissection is not indicated due to the non-metastatic behavior of this tumor. [ABSTRACT FROM AUTHOR]

An exact solution for the title problem is obtained. The lower five natural frequencies of transverse vibration are tabulated as a function of the mechanical parameters coming into play. [ABSTRACT FROM AUTHOR]

Introduction/Background: The aim of this study is to compare and evaluate the efficacy of a single treatment procedure with two different intravitreal corticosteroids (triamcinolone acetonide and dexamethasone implant) in patients affected by diabetic macular edema and non responsive to anti-inflammatory drops. Methods: 40 patients affected by diabetic macular edema (FT >300 μm) were included, 20 underwent 1 injection of triamcinolone acetonide and 20 received 1 implant of dexamethasone. BCVA and macular OCT were performed before the injection and at week 4, 8, 12, 16, 20. Intraocular pressure was also measured at each check up. Results: The efficacy of corticosteroids was similar in terms of macular thickness but the effect of dexamethasone persisted about 4 months while triamcinolone acetonide lasted almost two months. The IOP rose in 3 patients with triamcinolone acetonide and 5 in patients with dexamethasone but was controlled by medical therapy. No inflammatory adverse effect was reported in any case. Conclusions: The study showed that the two corticosteroids were similar in terms of efficacy but dexamethasone lasted about twice as long and considering the costs related to the duration of the effect we may argue that we should take into account these results for the sanitary expense. Acknowledgements: No sources of funding. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor about the role of gastroesophageal reflux disease as risk factor for laryngeal lesions.

This study deals with the determination of frequencies of vibration of clamped rectangular plates using a simple polynomial approximation. The plates are considered to be constructed from an orthotropic material such that the principal elastic axes of the materials are not parallel to the plate edges. A weighted-residual technique is used to solve the differential system, and the change in fundamental frequency is investigated as the material elastic axes are rotated with respect to the natural coordinate system of the plate. [ABSTRACT FROM AUTHOR]