Cyclosporin A stimulates Na+ transport across the isolated skin of Rana esculenta

Cyclosporin A (Cs A), added to the fluid bathing the internal surface of the isolated skin of Rana esculenta, increased short-circuit current (SCC) with a maximal effect at 5 microM. This effect was completely inhibited by amiloride (0.2 mM in the fluid bathing the external surface). By measuring both transepithelial fluxes of 22Na+ across symmetrical parts of the short circuited skin, Cs A was found to increase the net absorption of Na+. Naproxen (10 microM), a cyclooxygenase inhibitor, decreased the stimulation by Cs A of SCC, suggesting that in this stimulation prostaglandins are involved. The Cs A effect on Na+ transport could be caused by an inhibition of a Ca2+/calmodulin-dependent protein phosphatase, i.e. calcineurin, since: a) it is mimicked by another inhibitor of calcineurin, i.e. fenvalerate: b) the action of Cs A and fenvalerate on SCC are decreased by the calmodulin inhibitor W7.

Comparison of long-term hearing results after vestibular neurectomy, endolymphatic mastoid shunt, and medical therapy

OBJECTIVE

This study aimed to compare the hearing changes in the long term after vestibular neurectomy, endolymphatic mastoid shunt, and medical treatment in classic Meniere's disease.

STUDY DESIGN

A retrospective case review was conducted based on audiologic follow-up between 5 and 21 years.

SETTING

The study was performed at two centers in Bari University Hospital, one performing vestibular neurectomy as the first surgical procedure for Meinere's disease and the other, endolymphatic mastoid shunt.

PATIENTS AND INTERVENTIONS

Of 68 patients with intractable idiopathic Meniere's disease, 29 underwent middle fossa vestibular neurectomy, and 17 had endolymphatic mastoid shunt; 22 were offered surgery but declined.

MAIN OUTCOME MEASURES

Outcome measures were puretone average (PTA), speech reception threshold, and speech discrimination score before and after treatment.

RESULTS

PTA declined by an average of 9.3 dB in neurectomy patients, 13.3 dB in patients undergoing endolymphatic mastoid shunt, and 18.1 dB in patients who were offered surgery but declined. Patients were subdivided into two cohorts based on their preoperative or initial PTA. In the patients who had PTA scores worse than 50 dB initially, the PTA declined an average of 4.3 dB in the vestibular neurectomy group, 11.5 dB in the endolymphatic sac group, and 4 dB in the nonsurgical group. In the patients with PTA > or = 50 dB initially, the PTA declined an average of of 25.3 dB in the vestibular neurectomy group, 16.1 in the endolymphatic sac group, and 26.2 dB in the nonsurgical group. Although shunt patients with good hearing initially deteriorated less than neurectomy patients and less than patients who declined surgery, the difference was not significant.

CONCLUSIONS

These results indicate that patients with poor hearing stabilized, while patients with good hearing continued to deteriorate. The same conditions were observed in the patients who had surgery and those who were offered surgery but declined.

Remote masking in normal-hearing and noise-exposed chinchillas

Remote masking (RM), the phenomenon whereby an intense high-frequency masking noise elevates thresholds for low-frequency signals, has been shown to be sensitive to various types of hearing loss in humans. We performed two experiments to evaluate the chinchilla as a model of RM and to examine changes in RM associated with temporary threshold shifts (TTSs) induced by low-frequency noise exposure. Thresholds for 0.5-, 1- and 2-kHz tones were measured in quiet, then in the presence of a narrow-band (300-Hz-wide) masking noise centered at 3 kHz. In Experiment I, effective masking was measured as a function of masker level, from 48 to 98 dB sound pressure level (SPL; referenced to 20 microPa), to determine threshold and rate of growth of RM in the chinchilla. In Experiment II, RM was measured before, during and after exposure to a low-frequency noise known to produce TTSs in chinchillas (i.e., a 0.5-kHz octave band noise at 90 dB SPL for 6 h/day for 10 days). The results show that normal-hearing chinchillas have the same pattern of RM as humans, and that a noise exposure that produces TTSs also produces rapid and significant changes in RM.

Remote masking in noise-exposed chinchillas

Remote masking (RM), the phenomenon whereby an intense high-frequency masker elevates thresholds for low-frequency signals, has been shown to be sensitive to various types of hearing loss in humans and to temporary threshold shifts in chinchillas. In this experiment, RM was evaluated in chinchillas with permanent threshold shift (PTS). Thresholds for 0.5 and 1 kHz tones were measured in quiet and in the presence of an 88 dB SPL narrow band noise centered at 3 kHz in the animals exposed for 30 h to impact noise at 125 dB SPL as intensity. The results show that RM values are significantly lower in chinchillas with PTS than in normal hearing chinchillas.

Cholesteatoma in children: histopathologic findings in middle ear ossicles

Middle ear ossicles removed during ear surgery in 40 patients were examined in order to compare the histopathologic changes in children with those observed in adults. Bone resorption, mainly localized at the level of the periosteum and haversian canals in adults, was much more extensive in children. Replacement of bone by fibrous granulation tissue was observed in 60% of children's ossicles and in 27% of those belonging to adults. In children, extensive active resorptive osteitis of the ossicles was frequently associated with intensive round cell infiltration, which seems to play an important role in bone absorption and in the aggressiveness of cholesteatoma.

[Critical ratio: effects of contralateral masking on normal and pathological ears]

In order to evaluate the central interferences on the auditory efficiency, the effect of contralateral masking noise on Critical Ratio (CR) has been studied in 14 normal ears (control group), in 12 ears with cochlear disorders and in 6 with retrocochlear lesion (acoustic neuromas); in all cases the impairment was unilateral, while the other ear was normal. CR values were calculated for 1 KHz pulsed tones (duration 500 ms, rise/fall 25 ms, duty cycle of 50%); the masking noise was a wide band (90-20,000 Hz) delivered at 40 dB SL. The results have demonstrated that in the presence of contralateral masking noise, CRs don't modify both in the normal ears and in those with retrocochlear disorder, whereas they increase, almost always, in ears with cochlear deafness. These results demonstrate that the involvement of central auditory pathways, because of contralateral noise, makes the auditory efficiency worse, only in ears with cochlear dysfunctions; this behaviour seems to confirm the peripheral origin of CR.

[Psychoacoustic tests: effects of atropine]

The efferent pathways exert a control action on the function of the cochlear nucleus and hair cells. Acetylcholine is the neurotransmitter of the centrifugal system and its action can be blocked by atropine. In order to give a contribution to the knowledge of the function of the efferent bundle and of the cochlea efficiency we examined 10 young normal subjects before and after infusion of 1 mg of atropine i.v. a battery of three psychoacoustical tests (Remote Masking, Critical Ratio and Brief Tone Audiometry). After infusion of atropine we have shown an increase of 0.25 Hz hearing threshold, an increase of RC values and a decrease of RM values. It can be concluded that the pharmacological block of the olivo-cochlear bundle determines a stiffness of outer hair cells and basilar membrane; this finding means that the atropine can inhibit the facilitating activity of the efferent system on the cochlear performance.

[Facial nerve paralysis and mandibular fracture]

The authors describe three cases of peripheral facial nerve paralysis in patients with a mandibular fracture. In two cases, in which the onset of palsy was uncertain, the facial nerve injury was contralateral to the fractured side. Topodiagnostic tests showed neural damage at the third intrapetrosal portion and at the genicular ganglion. In one of the two patients tomography revealed a fracture line through the anterio-superior wall of the external auditory canal homolateral to the facial palsy. In the third subject palsy set in immediately after the trauma and was ipsilateral to the mandibular fracture; the facial lesion was localized at the genicular ganglion. In the first two cases, functional recovery was spontaneous (40 and 0 days after the trauma respectively). In the third subject, the nerve was decompressed surgically with a complete functional recovery two months later. The functional and clinical findings of these three cases show that a contralateral facial palsy secondary to a mandibular fracture resolves spontaneously while the traumatic displacement of the mandibular condyle may determine a temporal bone fracture sometimes followed by a lesion in the intratemporal portion of the facial nerve. An event such as the latter may delay functional recovery and thus warrant surgery such as in cases of Bell's palsy.

[Evoked oto-acoustic emissions in retrocochlear deafness]

In order to give a contribution to the genesis of the EOAEs, we have recorded the echoes in 6 subjects affected with unilateral acoustic neuroma, surgically proven (I. group); 11 subjects with sensorineural hearing loss with electrophysiological or balance signs of retrocochlear impairment (II. group) and 10 normally hearing young subjects as control group. In this study EOAEs have been recorded in response respectively to 3 ms 1000 Hz tone-burst and to 200-5000 filtered click, both sending with 2048 stimuli, at a repetition rate of 21 pps and different stimulus intensities ranging from 40 db SPL to saturation threshold in 10 db steps. The results have shown that the EOAEs were present in half of the tested patients in response to the clicks in both I. and II. group and in all the ears to the tone-burst although the 1.0 KHz audiometric threshold mean were > 65 db HL in I. group and in a third of the subjects in the II. group. The properties of EOAEs (detection and saturation threshold, dynamic range and duration) depended on the degree of hearing loss. These results suggest that acoustic tumor could determine a wallerian degeneration of the external fibers of the VIII nerve and consequently a dysfunction of the correspondent external hair cells of the cochlea, while in the II. group a contemporary or secondary involvement of the cochlear structures is possible.

[Evoked acoustic oto-emissions in cochlear deafness]

In order to give a contribution to the genesis of the EOAEs, we have recorded echos in 24 subjects with unilateral sudden deafness (I. group); 20 ears with Menière disease (II. group); 22 ears with progressive sensorineural hearing loss (III. group) and 10 normally hearing young subjects as control group. The results have shown that the EOAEs were present in 100% (I. group), 84.6% (II. group) and 86.3% (III. group) in response to the tone-burst; while the echos were present only in the 57.1% (I. group), 38.4% (II. group) and 45.4% (III. group) in response to the click, although the audiometric threshold mean were greater than 45 dB HL for 2-4 KHz and 1 KHz in the three experimental groups except for 2-4 KHz in the subjects with Menière disease (37.5 dB HL). The properties of EOAEs (detection and saturation threshold, dynamic range and duration) depended on the degree of hearing loss. Our results seem to corroborate the hypothesis that EOAEs could be also produced by a passive intracochlear mechanism attributable to the travelling wave of the basilar membrane provoked by the perilymph. In the normal ear this passive mechanism could be superimposed by an active mechanism, linked to the contractile activity of the outer hair cells with a consequent increase in amplitude of the EOAEs for the same stimulus intensity.

Candida and stapedial otosclerosis: histopathological findings

The stapes of 6 patients with stapedial otosclerosis was found to contain fungus hyphae (Candida) in the sectioned specimens. The footplate of all cases and the head of the stapes in 2 of the cases revealed single or multiple erosion cavities containing numerous thin branching PAS-positive fungus hyphae with swollen terminal endings and scanty blastospores. Osteoclasts were not observed; occasional osteoblasts, blue mantles and otosclerotic foci were seen. Four patients had been treated for several years with antibiotics and corticosteroids for recurrent serous otitis media and 1 patient had had frequent catheterization of the eustachian tube. It may be suggested that the Candida infection was a secondary event induced by a general and/or local immunodepressed condition.

Psychoacoustical performance in children

In order to contribute to knowledge of the elementary auditory functions in infancy, a group of normally hearing children below the age of four years was examined using advanced tests for cochlear (remote masking, brief-tone audiometry, critical ratio) and central auditory functions (masking-level difference). The results showed that both cochlear and central auditory functions were almost the same in three-year-olds as they were in adults, if not better. This behavior is similar to that recorded with electrophysiological methods and leads to the conclusion that at age three years the auditory system has completed its neurofunctional maturation and it is therefore completely efficient in its elementary psychosensorial functions.

Subclinical changes of auditory function in the aged

Elderly normal hearing subjects were studied using tests for cochlear functions (remote masking, brief tone audiometry, critical ratio, evoked otoacoustic emission), for neural auditory function (tone decay) and for central auditory functions (ipsilateral vs. contralateral acoustic reflex, tonal masking level difference). The findings demonstrated that ageing can cause subclinical abnormalities, almost consistently localized to the inner ear vibrating structures and only occasionally to the sensory and/or neural elements.

[Epidemiological study of dental caries incidence in a group of 10-year old children in USSL 13, Veneto region]

The Authors, after a study in depth of the incidence of the caries in a ten years old population, following the advices of the HWO, describe on their territory an occurrence of the caries desease similar to the value referred on other works of research published in the same Region, in any case not so far from these pointed by the HWO for the year 2000. But there is still much to do in the prevention and therapy.

[Epidemiological study of gingivitis incidence in relation to hygiene habits in a group of 10-year old children in USSL 13, Veneto region]

The Authors, after an attentive study about a population of 799 ten years old scholarboys, have found out the hygiene of the mouth is a problem thoroughly felt, but the quality isn't the quantity. Therefore we need a wider prevention, using the informations and education in the scholar and familiar world, and not only in the specialistic environment.

Cholesteatoma surgery: open vs closed tympanoplasty

The purpose of this report is to compare closed tympanoplasty (canal wall up) and open tympanoplasty (canal wall down) performed in ears with extensive cholesteatoma operated on and followed up during the past 11 years. The study has demonstrated that there are no significant differences between open and closed tympanoplasties in terms of both postoperative subjective problems and auditory results. The only definite difference relates to recurring cholesteatoma: canal wall-up operations are complicated by recurrence of cholesteatoma in a not insignificant number of ears and require a planned two-stage procedure in all the cases. By contrast, the postoperative clinical course of open tympanoplasties has been only rarely affected by cholesteatomatous complications. It is concluded that reduction of cholesteatoma recurrence to the greatest degree possible necessitates removal of the canal wall. Open tympanoplasty is an effective alternative for closed tympanoplasty in all cases in which there is a contraindication to preserving the canal wall and in all patients whose medical or social conditions prevent scheduling an operation in more stages.

Otomastoid cholesteatoma in children: histopathological findings

Clinical experience has shown that the otomastoid cholesteatoma is more aggressive and has a less favourable prognosis in the child than in the adult. In an attempt to verify whether, in children, the clinical behaviour of the cholesteatoma depends on the histomorphological characteristics of the perimatrix, we carried out a study of samples taken from 30 subjects under 16 years of age and from 30 adults (control group) during surgery for otomastoid cholesteatoma. The study took into account the number of plasmacytes, lymphocytes, macrophages, granulocytes and giant cells per high potency field (X 630). The results showed that in young subjects the perimatrix of the cholesteatoma is richer in mononuclear inflammatory elements with evidence of enzyme-collagenase activity. On the basis of this behaviour the authors conclude that the histomorphological characteristics of the surrounding matrix can play an important role in the pathogenesis of cholesteatoma and may explain the clinical differences that can be seen between cholesteatoma in children and in adults.

ABR in multiple sclerosis. Ipsi- versus contralateral derivation

Brainstem auditory evoked potentials (ABR) were recorded simultaneously between vertex and ear lobe, ipsi- and contralateral to the stimulated ear in 53 subjects with confirmed (19) or undefined (34) multiple sclerosis. Results were compared with those obtained in a control group of 20 normal-hearing adults. The control group showed that significant latency differences exist between ipsilateral and contralateral recordings. Definition of abnormality was based on absence and separation of waves. The results showed that the use of contralateral derivation in ABR recordings increased detectability from 74% to 89% in patients with confirmed MS and from 9% to 21% in cases of undefined MS. It is proposed that parameters of contralateral ABRs be included among the criteria used for the otoneurological diagnosis of patients with CNS lesions.

Audiologic findings in presbycusis

Presbycusic Ss (N: 64) were studied using tests for cochlear functions (SISI test, Metz test, delta F threshold, remote masking), for retrocochlear involvement (tone-decay test), and for central auditory impairment (tonal binaural MLD, ipsi- vs contralateral acoustic reflex). Recruitment was present in about half the cases; remote masking (supposed a test of stiffness of the cochlear partition) was almost always pathological; tone decay rarely was abnormal; tonal MLD and/or acoustic reflexometry yielded pathologic values in more than half of the Ss. Tonal test patterns demonstrated that in presbycusis there is a frequent alteration of the monaural and binaural analytic processes of intensity, frequency and phase; a constant increase of stiffness in the hydrodynamic system of acoustic energy transmission; and, sometimes, an increase of resistance of neural transmission.

Clinical and radiological findings in subjects with unilateral Ménière's disorder

In order to contribute to the knowledge of the possible causes of Ménière's disorder, the authors have conducted systematic studies based on blood analysis and on petrous bone radiological examinations in patients suffering from unilateral Ménière's disorder and in two control groups, one of patients with unilateral sudden sensorineural deafness and the other one of normally hearing subjects suffering from neurological diseases. Blood tests have revealed systemic disorders (dyslipidosis, hypoglycaemia, hyperglycaemia, hypothyroidism lues) in 49%, 48% and in 50% of the subjects respectively with Ménière's disorder, with sudden deafness, and with normal hearing. As to the radiological study, changes of the temporal bone (absence or small cells pneumatization and/or absence or narrowing of the vestibular aqueduct) were found in 78% of ears with Ménière's disorder, in 34% of ears with sudden deafness and in 46% of normal ears.

[Cortical responses evoked by vibrotactile sensations in deaf children]

Vibrotactile evoked responses (VER) to 250 and 500 Hz presented respectively at 50 and 70 dB HL by BC vibrator placed on right thumb, were recorded in 20 children (10 with pathological EEG) with severe sensorineural hearing loss, or deaf since birth, both to control accuracy of cortical responses to high intensity auditory stimuli and to diagnose central non auditory pathways lesions. The results have shown that: VER are present in subjects with severe sensorineural hearing loss or deaf; in children with auditory lesions VER have parameters different from auditory evoked response (AER); VER recording is not related both to the presence of auditory lesions and to neurological pathology.

[Effects of diazepam on stapedius reflex: physiological research]

The effect of diazepam (10 mg i.m. X 7 days) on crossed and uncrossed acoustic stapedius reflex parameters (threshold, amplitude and duration) has been studied in 7 normal hearing subjects. The results showed that diazepam has a not clinically significant damping effect on the threshold, the amplitude and, very often, the duration of both ipsilateral and contralateral acoustic stapedius reflexes.

Clinical experience with remote masking

Remote masking (RM) consists of a rise of the threshold for low-pitched tones when the ear is exposed to a high-frequency noise band delivered with high intensity. This phenomenon has been attributed to mechanical non-linear distortion of the cochlear partition, as an effect of the envelope of a non-uniform signal. The authors studied RM in patients suffering from unilateral Menière's disorder, acoustic neuromata, other sensorineural lesions and presbyacusis. The behaviour of RM in the different experimental groups shows that the RM value is normal in acoustic neuromata; it is variable and not related to the severity of the hearing loss in sensorineural losses, and it is reduced in the affected ear in patients suffering from Menière's disorder. Finally, RM is reduced as a function of ageing, progressively and symmetrically in both ears in presbyacusic subjects. The results of the research seem to confirm the hypothesis that RM may be due to mechanical effects in the inner ear and suggest the possibility of using RM as a test of cochlear partition rigidity.

[Remote masking as a test of cochlear conductive hearing losses (author's transl)]

The authors studied the remote masking (RM) in patients with Menière's disorder during the hearing loss fluctuations produced either by the disorder or by the glycerol test (Klockhoff). The RM was recorded for pulsed tones of 250, 500 and 1 000 Hz; the masker was a continuous narrow-band noise centered at 3 000 Hz, with 305 Hz (2 875-3 180 Hz) bandwidth, delivered at an overall level of 98 dB SPL. The results showed that the RM decreases during the acute phase, i.e. when the hearing loss increases, and, increases if the glycerol tests do not significantly modify the RM value. They seem to confirm the hypothesis that the RM may be due to a mechanical effect in the internal ear and suggest the possibility of using the RM as a test of end-organ rigidity.

Remote masking in presbycusis

Remote Masking (RM) (a rise in threshold for low-frequency tones when the ear is exposed to a high intensity noise band of high frequency) has been attributed to mechanical nonlinear distortion of the cochlear partition, as an effect of the envelope of a nonuniform signal. Clinical studies using RM have revealed RM is normal only when both the endolabyrinthine pressure and the cochlear hydrodynamics are normal. Increasing the stiffness of the cochlear partition affects adversely the mechanism of motion of the cochlear duct and reduces RM values. We studied RM in normal young Ss and in patients with presbycusis in order to determine whether aging of the inner ear also induces stiffness of the cochlear partition. In presbycusic Ss the RM values were indeed reduced symmetrically in both ears and progressively as a result of aging. Thus RM demonstrates the existence of cochlear conductive presbycusis and can be considered a useful test of stiffness of the cochlear partition.

Masking level differences in central nervous system diseases

The relationship between the tonal masking level difference performance and the behavior of the "sensitized speech tests" according to Bocca and Calearo, were studied in subjects with normal hearing who were suffering from CNS diseases. The results have shown that pathological masking level difference values are present in all cases with pathological sensitized speech tests, and are related principally to the following two conditions: (1) the bulbo-pontine lesions and (2) the central hearing functional asymmetry. In subjects with normal hearing who have CNS diseases, pathological tonal masking level differences indicate the existence of central hearing pathways lesions.