Comparative evaluation of ABR abnormalities in patients with and without neurinoma of VIII cranial nerve.

Although the diagnostic reliability of auditory brainstem responses (ABR) in acoustic neuromas has been revised due to its poor sensitivity (demonstrated above all in smaller tumours), and its limited specificity, this method is still used as the initial otoneurological approach. To contribute to the clinical use of this method, in particular with the aim of reducing the number of false positives, a retrospective study was carried out in two groups of patients affected by unilateral sensorineural hearing loss with auditory brainstem response abnormalities: in the first group (50 cases: true positives) hearing loss was the expression of an acoustic neuroma shown by magnetic resonance imaging, in the second group (130: false positives) magnetic resonance imaging was negative. In both groups, auditory brainstem response recordings showed abnormalities suggesting retro-cochlear disorders such as: (1) complete absence of response not justified by the extent of the hearing loss, (2) presence of only wave I, (3) increase in wave V absolute latency with normal I-V interpeak latency, (4) increase in wave V absolute latency, the sole component, 5) increase in wave V absolute latency and I-V interpeak latency. A comparison between the two groups made it possible to show that the finding of "major" auditory brainstem response alterations (complete absence of response not justified by the extent of the hearing loss or presence of only wave I) is correlated with a high probability of the presence of a neuroma, while other abnormalities (wave V latency and I-V interpeak latency increase) have no particular predictive value since percentages are almost identical in the two groups. Wave V latency increase with normal I-V interpeak latency was observed in only one case of acoustic neuroma and this clinical finding is not easy to interpret. It would not appear possible, based on current knowledge, to further improve the reliability of this test, and, therefore, its use in oto-neurological diagnostics remains limited.

[Cisplatin and carboplatin-induced ototoxicity in children: clinical aspects and perspectives for prevention]. / Ototossicità da cisplatino e carboplatino in età pediatrica: aspetti clinici e prospettive di prevenzione.

In 70% of the cases of malignant neoplasms in pediatric patients antiblast therapy is used. The administration of platinum compounds, Cisplatin (CDDP) or Carboplatin (CBDCA), often at high cumulative doses, necessarily implies a certain degree of toxicity which normally takes on secondary significance in the healing of the child. Among the side effects, early and delayed ototoxicity is well known and, in the child, take on particular aspects. While not abandoning the treatment of the base pathology, the therapeutic findings, increasingly comforting in terms of long-term survival, require more accurate evaluation and overall control of the quality of life of these young patients. Since initial cochlear damage can be reversible, auditory function must be carefully monitored in order to prevent the lesions from becoming permanent, in particular prior to the onset of speech. For this reason a retrospective study was made of a group of 26 children affected by malignant neoplasms all of whom had undergone a polychemotherapy protocol with the administration of CDDP in 14 cases and CBDCA in 12 cases. All these young patients were monitored with conventional audiometry. The presence of different variables (antiblastic drug administration schedule, course of the disease, general conditions) only permitted evaluation of a single correlation: between auditory function at the end of the treatment (or after a few cycles of therapy) and the overall dose of CDDP or CBDCA administered. In 16 cases (62%) typical bilateral perceptive deafness was detected progressively involving the hyperacute and acute frequencies. The finding of hearing loss was significantly greater in the patients treated with CDDP (86%) vs. those treated with CBDCA (33%). Moreover, analysis of the results showed that, within certain limits, ototoxicity can depend more on individual sensitivity to the drug than to the total dose administered. The results confirm the well-known ototoxicity of platinum compounds, in particular CDDP. As ever improved therapeutic results are achieved in the treatment of malignant neoplasms in pediatric patients, greater attention can be paid to the quality of life of these young patients after the disease has been healed. Careful monitoring of auditory function can be extremely important in the pursuit this objective; indeed, this makes it possible to adjust antiblast drug administration, particularly in the later stages of treatment, customizing the treatment schedule to individual patient sensitivity.

[Late deterioration in bone conduction after stapes surgery: a retrospective analysis]. / Deterioramento tardivo della conduzione per via ossea dopo chirurgia della staffa: analisi retrospettiva.

In spite of the well-consolidated technique that otosclerosis surgery has built up, there are several aspects that have yet to be satisfactorily explained. One of these is the greater long-term "vulnerability" that appears to characterize an ear that has been operated on compared to a healthy one. In searching for a feasible explanation of this phenomenon and its therapeutic implications, a retrospective analysis of 26 cases was carried out on patients who had been operated between 1966 and 1995 and had come to our attention between 1989 and 1999 due to a rapid, late deterioration in bone conduction. Short-term treatment was pharmacological and surgical in 19 cases and exclusively pharmacological in 7 cases. The analysis of the results of therapy was based on an evaluation criterion of PTA (250-4000 Hz) > 5 dB, calculated on the basis of the bone conduction threshold values. Possible prognostic factors were searched for by means of a multivariate analysis that took as its dependent variable the bone conduction hearing threshold following therapy and as independent variables the age, gender, monolaterality of the otosclerosis ascertained, a positive medical history for analogous phenomena and for previous surgical revision, concomitant vertigo, the time that had elapsed between initial treatment (operation) and deterioration, the technique adopted during the first operation, the extent of the rapid deterioration, the audiometric characteristics at the outset of treatment for the acute episode, the time that had elapsed between deterioration and treatment, the type of treatment, possible reopening of the oval window, and intraoperative findings of a perilymphatic fistula. In the 7 cases managed with pharmacological therapy alone, improvement was seen in 3 cases while the condition remained unvaried in 4 cases; surgical revision (which in 5 cases enabled the presence of a fistula to be ascertained) associated with pharmacological therapy brought improvement in 4 cases, worsening in 4 cases, and no variation of the condition in 11 cases. The only prognostic factor detected, of an unfavourable nature, was the presence of anacusis upon examination. The results obtained do not enable unambiguous conclusions to be drawn: it may in any case be inferred that, at least in certain particular cases, above all when a false cochlear deterioration or the presence of a fistula is suspected, an "aggressive" therapeutic approach may be justified.

Plasma lipoproteins in rats with experimental biliary obstruction. I. A chemical study.

Acute biliary obstruction in the rat is associated with striking alterations of the plasma level and the physico-chemical properties of plasma lipoproteins. 1. The level of very low density lipproteins (VLDL) in plasma increases from 2 to 3 fold. The chemical composition of VLDL is characterized by a high content of phospholipids and cholesterol and by a diminution of the relative content of triacylglycerols and protein. On cellulose acetate electrophoresis, VLDL show a beta-mobility. 2. The plasma concentration of low density lipoproteins (1.019--1.063 g/ml, LDL2) increases several fold above the control level. Phospholipids and unesterified cholesterol are the major components of this fraction which contains only a minute amount of cholesteryl ester (4%) and triacylglycerols (10%). LDL2 contain a component which migrates to the cathode in 1% agar gel electrophoresis. Separation of LDL2 by gel filtration on 2% agarose column results in the identification of three subfractions. Subfraction I contains a large proportion of cholesterol and triacylgylcerols, subfraction II is rich in unesterified cholesterol and phospholipids whereas subfraction III has a chemical composition fairly similar to that of the control LDL2. 3. The level of high density lipoproteins (HDL) also increases after bile duct ligation. The chemical composition of HDL2 (1.063-1.125 g/ml) is characterized by a high content of unesterified cholesterol and phospholipids and by a remarkable reduction in the content of cholesteryl esters and protein.