Biomedical subjects

M Maurizi

Publications and source records attributed to M Maurizi.

At least 109 records · Page 6Linked to original sources

PubMedDate not supplied

Hormonal receptor site alterations in the etiopathogenesis of otosclerosis.

The authors have studied calcium 45 uptake and cAMP intracellular levels in normal and otosclerotic bone cell cultures after stimulation with calcitonin in the presence or absence of propranolol. The results seem to demonstrate that poststimulatory 45Ca incorporation is slightly different in normal and otosclerotic cell cultures, being slower but longer lasting in the latter. Propranolol administration markedly inhibits 45Ca uptake in normal cells, while in otosclerotic cells a massive intracellular penetration becomes evident after an initial inhibitory phase. Also cAMP intracellular levels behave differently; a marked increase, followed by a rapid decrease, can be detected in normal cells after stimulation with calcitonin, while in otosclerotic cells, the increase is slower and followed by a long lasting reduction. Adding propranolol reduces cAMP levels in normal cells, while it increases levels in otosclerotic cells. The different behavior of calcium metabolism and cAMP levels after stimulation with calcitonin, depending upon the presence or absence of propranolol, seems to indicate an alteration of the transducing mechanism between stimulus, receptor, and cellular effector in otosclerotic cells.

Animals↗

PubMedDate not supplied

Mucociliary clearance and mucosal surface characteristics before and after total laryngectomy.

Forty heavy smokers, all males aged between 40 and 70 and affected by laryngeal cancer underwent mucociliary clearance evaluation the day before total laryngectomy, 60 days after and, in 6 of them, 5 years later. Specimens of nasal and tracheal mucosa were obtained during laryngectomy and other subsequent operations. Before total laryngectomy, no significant changes in nasal mucociliary clearance were observed in smokers and controls, and the nasal ciliary carpet was fairly well preserved. Bronchial mucociliary clearance was impaired in all patients, owing to the coexistent chronic obstructive bronchitis. 60 days after the operation, nasal mucociliary clearance was significantly improved when compared with the preoperative data and controls, owing to the increase in the endonasal temperature and humidity, and to the reduction of the nasal blood flow and disappearance of the nasal cycle, which follow tracheostomy. Surface morphologic studies show a change in the squamous epithelium of the anterior third of the nasal fossa into a columnar ciliated one. During the first 3 months after the operation, tracheobronchial mucociliary clearance increased of 50% vis-à-vis the preoperative data. During this period a clinically evident bronchial hypersecretion was observed. The reduction in nasal and tracheobronchial mucociliary clearance function which became evident 6 years after the operation, is probably due to secondary chronic infections.

Adult↗

PubMedDate not supplied

[Carotid body tumors: the clinical, diagnostic and therapeutic aspects].

The authors discuss the epidemiology, histology, symptomatology, diagnosis and therapy of carotid body tumors, basing their discussion on three personal observations and on a case of cervical dermatocyst which showed clinical and radiological data consistent with diagnosis of a glomus tumor. Chemodectomas of the neck are more often seen in the carotid body and are considered histologically benign, although they might induce local or distant metastases. Clinical presentation is often non-specific and may only consist in a slowly growing mass in the higher jugular-carotid region. Among the various imaging techniques (CT, MR), supra-aortic selective angiography, including digital subtraction techniques, is now considered the most reliable tool, while ultrasonography and gammagraphy with 99mTc-gluconate or 131I-MBG are recommended for screening and family testing purposes. Biopsy is to be avoided as it is very likely to cause massive bleeding and because of the high percentage of false negatives. Surgery is the choice treatment, and lateral cervicotomy is the recommended approach for exeresis of the mass, while radiotherapy should be planned in patients with precise contra-indications for surgery and when the tumor mass has already reached the skull base. Pre-operatory selective embolization is still controversial.

Adult↗

PubMedDate not supplied

Synthesis and secretion of glycosaminoglycans and proteins in human normal and otosclerotic bone cells.

Some biosynthetic activities of normal and otosclerotic temporal bone cultures have been studied. Bone cells were cultured for 24 hrs. in medium containing 3H-glucosamine, 35SO4 or 3H-proline. Labelled glycosaminoglycans (GAG) and proteins were precipitated from cells and media. In otosclerotic bone cells there was an evident reduction in the synthesis and secretion of radiolabelled macromolecules. The inhibitory effect was always greater in the extracellular than in the intracellular compartment. Some glycosidases were also studied. Otosclerosis decreased the activity of all enzymes examined, indicating that the lower GAG synthesis and secretion in otosclerotic bone cells were not due to an increased degradation.

Bone and Bones↗

PubMedDate not supplied

[Magnetic fields evoked by auditory stimuli: a normative study].

After outlining the fundamentals of biomagnetism and their possible clinical applications, the authors report the results of a normative study on auditory magnetic fields performed on 18 normally hearing subjects between the ages of 25 and 30. Having presented a thorough review of the literature, they then describe the recording technique employed, the dcSQUID biomagnetic system for signal detection, the shielded room, the characteristics of the stimulus. The auditory magnetic response is characterized by three main waves (P4Om, N100m, P200m) whose latency and amplitude values were calculated. Moreover, in order to localize dipolar activity, certain parameters, such as P and T, were taken into consideration. Localizations were made using a spherical volume conductor or with MRI, which was in any case employed in all the subjects. The waves, especially the N100m recorded contralaterally to the stimulus, showed a reduced latency and an increased amplitude when compared to those recorded ipsilaterally. Moreover, a systematic posterior shift of the N100m source into the left hemisphere with respect to the right one was detected. In conclusion, the authors emphasize the need to study electric as well as magnetic responses in order to better understand auditory cortical functions.

Acoustic Stimulation↗

PubMedDate not supplied

[Ectopic thyroid gland].

Based upon the observation of four cases of ectopic lingual thyroid the authors discuss the etiopathogenetic, clinical-diagnostic and therapeutic aspects of this pathology. The clinical characteristics of the mass, scintigraphy, echography and CT scan of the neck, the T3, T4, TSH doses in the blood and fine needle aspiration of the mass have made adequate appraisal of its possible nature and have led to the identification of the presence of thyroid tissue in other sites. In regard to therapy, the authors believe that surgery is compulsory for patients showing clinical signs of upper airway obstruction despite suppressive therapy or when the lesion shows signs of malignant degeneration. After having mentioned the more commonly employed surgical approaches, emphasis is placed on median pharyngotomy as it permits the best visualization of the region, a careful excision of the mass and a valid control over bleeding. In most cases a tracheotomy proves unnecessary. The post surgical hormonal situation suggests the opportunity of a possible substitutive therapy with synthetic hormones or thyroid derivatives.

Adolescent↗

PubMedDate not supplied

[Brain mapping of middle latency auditory potentials in normal subjects].

The MLRs of 20 normal hearing adults were recorded by cerebral mapping. In regard to the Pa and Na waves, it is suggested that two different generation sites exist because of the different spatio-temporal distribution of the waves over the scalp. It is demonstrated that amplitudes measured by the "grand average" technique are constantly lower than those obtained with the manual determination, and they conclude that manual determination represents the most reliable method in order to calculate waves amplitude. Finally, it is suggested that, due to the different generation sites for Pa and Na waves and to the uneven distribution of the Na wave over the scalp, Pa amplitude should be measured from the baseline and not from the Na negative deflection. Moreover, in 14 cases, when one ear was stimulated the Pa wave obtained at most recording points was significantly larger than the one recorded contralaterally.

Acoustic Impedance Tests↗

PubMedDate not supplied

[Considerations on analysis time duration in a posturographic study in normal subjects].

In order to evaluate the importance of analysis time on posturographic parameters (average X, Y and R, Sway Path, Sway Area, Ellipse Area) both with eyes open and closed, 24 normal subjects were examined for an overall period of 60 seconds. Mean +/- 1 SD values of each parameter were obtained for each time interval (0-20, 20-40, 40-60 sec.) into which the overall period was divided. With the eyes open, the parameters for each time interval did not differ significantly and they were always lower than those obtained with the eyes closed. On the other hand, with the eyes closed, there was a significant reduction in the various parameters as analysis time progressed. In 4 out of 24 subjects an inverse behaviour was detected. The authors conclude that the open-eye analysis time could be limited to 20 sec while, due to changes observed in the various posturographic parameters, closed-eye analysis time should be extended to 60 seconds. The analysis time may prove important in identifying peripheral or central vestibular pathologies since it may be that some of them induce earlier alterations of posturographic parameters while in other pathologies such changes are observed later on.

Adult↗

PubMedDate not supplied

[Our experience with mandibular fractures].

The authors relate on their own experience concerning etiology, diagnosis and treatment of mandibular fractures. 320 patients (252 males and 68 females) aged between 6 and 82 years with posttraumatic fractures of the mandible, 188 with a single and 132 with multiple fractures, underwent surgical and/or orthopedic treatment. Interosseous wiring and seldom application of metallic plates were the preferred techniques when surgery was performed. Intermaxillary fixation was carried out when the orthopedic treatment was needed. Often both methods were associated. In 10% of the condylar fractures the condyle has been removed. Functional results were excellent and no serious complications could be observed. In 11% of the cases with condylar fractures some limitation of the mandibular movements could be observed, while when condyles were not involved malocclusion could be observed in 3% of the cases. The authors discuss upon etiology, by comparing their own with other experiences, upon diagnosis, which does not seem difficult if adequate radiological investigations are carried out; finally they relate briefly on the advantages and disadvantages of the different surgical and non surgical techniques. Based on their experience they conclude that interosseous wiring and, in selected cases, the application of metallic plates, using an external approach, mostly associated with intermaxillary fixation, represent a safe and adequate treatment for almost every fracture of the mandible.

Adolescent↗

PubMedDate not supplied

[Recent advances concerning etiopathogenesis of nasal polyposis].

The way nasal polyps arise and why they tend to recur is still unknown. Quite frequently they are found in association with asthma, rhinitis and ASA-intolerance, thus suggesting a multifactorial etiopathogenesis. The incidence of atopy in patients affected with nasal polyposis is quite low (16.8%). Recent studies stress the involvement of mast cell mediators due to various degranulating stimuli other than those mediated by IgE. The finding of the interleukin-2 receptor (IL2-R) on murine mast cells and on human peripheral blood basophils, together with the possibility of inducing basophil degranulation through IL2 stimulation, have led the authors to seek IL2R on human nasal polyp mast cells and to study subpopulations of nasal polyp lymphoid infiltrates. Nasal polyps obtained from 4 patients, admitted to the E.N.T. Department of the Catholic University of Rome in 1988, were snap frozen soon after their surgical removal through transmaxillary ethmoidectomy. In this study the following monoclonal antibodies (MoAb) were used: Leu-2a (CD8), Leu-3a/3b (CD4), Leu-4 (CD3), anti-HLA-DR and anti-IL2-R (CD25), OKM1 (CD11), OKB2 (CD24) and 1HT4-4H3 (CD 25). In no patient was there evidence of atopy, asthma or ASA-intolerance. Several mast cells (MC) were observed, chiefly in the connective axis and perivascular areas. These cells were characterized by a large number of cytoplasmatic monomorphic granules. The MC displayed the IL2-R and they were very often close to T-lymphocytes. T-cell subpopulations were predominantly composed of CD4-positive cells (about 75% of all lymphocytes) often associated in clusters and located both in the submucosa and in the connective axis. CD8-positive cells (10-15% of the lymphoid cells) were located most often just under the epithelium. They were hardly ever scattered within the CD4-positive cell clusters. Almost all T cells were activated, above all those surrounding the MC. These results would appear to suggest the presence of a cell-mediated immune response in nasal polyp pathogenesis where MC degranulation, determined by activated T-cell cytokines, plays an important role.

Adult↗

PubMedDate not supplied