Biomedical subjects

J Marco-Algarra

Publications and source records attributed to J Marco-Algarra.

9 recordsLinked to original sources

PubMed2001

Inner ear lesion alters acoustically induced c-Fos expression in the rat auditory rhomboencephalic brainstem.

The pattern of c-Fos expression was mapped in the adult rat's brain following unilateral cochlear lesions. In normal and cochlear lesioned rats, c-Fos expression was induced with sound stimuli. Acoustic stimulation consisted of pulses of four tones. An additional control group consisted of non-stimulated rats. In the cochlear nuclei (CN), c-Fos activation was scarce in isolated rats and increased strongly following sound stimulation. Following unilateral cochlear lesion, acoustically driven expression was decreased in all CN in both the lesioned and the untreated sides. The ventromedial periolivary nucleus and the rostral periolivary nucleus showed c-Fos activation in isolated conditions and were strongly activated following sound stimulation. The rest of the superior olivary complex showed no c-Fos activation in isolated rats and a weak activation following sound stimulation. Following unilateral cochlear lesions, acoustically driven expression was decreased in some, but not all superior olivary nuclei in both the lesioned and the untreated sides. In the lateral lemniscus complex, c-Fos activation was scarce in isolated rats and increased strongly after stimulation. Following unilateral cochlear lesion, acoustically driven expression decreased bilaterally in all nuclei. We have found that unilateral inner ear lesions lead to bilateral impairment of the capability of acoustic pathway neurons, to being c-Fos-activated following sound stimulation.

Acoustic Stimulation↗

PubMed1993

The prognostic value of mucociliary clearance in predicting success in tympanoplasty.

Mucociliary and equipressive eustachian tube functions have been studied, using saccharin solution (five per cent sodium saccharinate) and tubal manometry respectively, in 58 ears with chronic disease undergoing tympanoplasty. The position of the perforation site determines the results as the poorest results are obtained from the posterior ones, positive cases (47 per cent) and mean transport time (37.7 minutes), compared to the greater percentage of positive cases (86 per cent) and mean transport time (22.2 minutes) for anterior perforations. When both parameters are analysed together there is a direct relationship between normal equipressive function and normal mucociliary transport time and between negative transport time and tubal blocking. Significant difference in transport times have been found for the anterior and posterior perforations being shorter for the anterior ones. When surgical outcome is correlated with mucociliary transport, the normal transport time percentage is seen to be considerably higher in the success group (50 per cent) than in the failure group (22 per cent).

Adolescent↗

PubMed1993

Vestibular decruitment: an indicator of central pathology?

Torok studied the ratio obtained between the responses to two different heat stimulation intensities of the same temperature. A decrease in response to the strong stimulus (i.e., a diminished ratio) was called "vestibular decruitment," and was regarded as a topodiagnostic indicator of central vestibular lesion, reflecting "adaptation" or "fatigue." The authors studied the reliability of vestibular decruitment obtained by Torok's technique in the indication of central vestibular pathology. Twenty-eight normal individuals and 30 patients previously diagnosed by other methods with diffuse pathology of the central nervous system were evaluated. The results obtained show that the two stimuli used are both supraliminal and of different intensity regarding the labyrinth. In no case was vestibular recruitment obtained. In view of the high percentage of normal individuals (57.14%) who presented vestibular decruitment, we consider the latter to lack topodiagnostic value as an indicator of either central or vestibular pathology; the smaller response to the mass stimulus might be explained by the vestibular habituation phenomenon that occurs on applying Torok's technique in both normal individuals and in patients with central vestibular pathology.

Adolescent↗

PubMed1993

Prognostic factors in tympanoplasty: a statistical evaluation.

In a group of 52 patients with chronic otitis media that underwent a myringoplasty, pressure equalization mucociliary clearance of the Eustachian tube and degree of pneumatisation of the mastoid have been studied, and their statistical relationship with surgical outcome evaluated. The only statistically being significant correlation was mucociliary clearance time.

Adolescent↗

PubMed1991

Cholesteatoma in children: results in open versus closed techniques.

Cholesteatoma in children presents characteristics that differentiate it from the adult condition. Surgery has been performed in 55 ears. The main reason for referral was otorrhoea (83 per cent), either alone (29 per cent) or with hearing loss (54 per cent). Apart from three cases with an intact eardrum, a perforation was always present mostly posterior-superior (50 per cent). Open techniques were performed in 27.3 per cent of the ears and the closed technique in 72.7 per cent. Only in 18 per cent of cases was the ossicular chain normal and mobile. The attic was occupied by cholesteatoma in 79 per cent. Recurrence took place in 37 per cent and 13 per cent of the closed and open techniques respectively. Open techniques tend to be employed in the presence of extensive disease, whereas the closed technique is reserved for those with a more localized problem.

Adolescent↗

PubMed1991

Comparative study of the effect of gentamicin on the vestibulo-ocular and visual vestibulo-ocular reflexes in the cat.

The ototoxic effect of an aminoglycoside, gentamicin, on the vestibular system was investigated in cats given daily doses of 40 mg/kg i.m. for 14 days. Periodically, measurements were made of the vestibulo-ocular reflex (VOR) and visual vestibulo-ocular reflex (ViVOR) responses induced by rotatory stimuli at various frequencies from 0.0125 Hz to 0.8 Hz. After the cessation of drug administration, a progressively declining response to VOR stimuli continued, manifested by gain (ratio of peak response to peak stimulus amplitude) and phase relationships. The ViVOR was affected only in the gain measurements. The changes in the response amplitude (gain) were greater for the VOR than for the ViVOR responses and also for the lower (0.0125 Hz) than for the higher frequencies (0.8 Hz). There was some indication that the responses improved about one month after treatment was terminated. All of these specific response changes in cats are comparable to the known effects of aminoglycides in humans, and the same theoretical interpretation of the data in the context of a model of vestibular function can be applied in both cases.

Animals↗

PubMed1984

Experimental contribution to the origin of brain-stem potentials.

The origin of the different BSP waves is open to discussion. In this work we analyze the response curves with surface and intranuclear electrodes in cats, both before and after inducing electrolytic lesions in acute and chronic phase, in order to study the subsequent alterations. We found that waves whose origins are attributed to specific regions of the acoustic pathway when carried out with surface electrodes, fail to correspond with the results obtained by intranuclear electrodes. On the other hand, although the lesions to the lowest part of the acoustic pathway (cochlear nuclei) cause important alterations in the recordings, these alterations become smaller as the lesions are induced higher up the pathway. Thus, we believe that the origin of the different BSP waves is due to the sum of potentials of different zones of neuron activation, and not to specific locations of the acoustic pathway; this is more evident in the delayed waves.

Animals↗

PubMedDate not supplied

Cis-diaminedichloro platinum ototoxicity. An experimental study.

Four groups of guinea pigs received different doses of cis-platinum. SEM and TEM showed a direct relation between the dose and the damage. The first row of OHC is the first one to be damaged. The IHC are more resistant than the OHC. The pattern of destruction is similar to the one produced by the aminoglucoside antibiotics.

Animals↗

PubMedDate not supplied

[Long-term (5 years) comparative study of patients with phonatory prosthesis: myotomy versus non-myotomy].

A group of 122 patients that underwent a total laryngectomy and phonatory prosthesis surgery are evaluated after five years follow up. We compared three different techniques. 1) Herrmann technique; 2) total laryngectomy and inferior pharyngeal constrictor myotomy, and 3) classic total laryngectomy. Failures and complications are analyzed. A functional evaluation of the patients is made by means of oesophageal manometry and pharyngo-oesopyhageal isotopic transport. Voice quality is assessed in each group. As a conclusion inferior pharyngeal constrictor myotomy is very positively evaluated.

Aged↗