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Biomedical subjects

A Morgon

Publications and source records attributed to A Morgon.

At least 109 records · Page 6Linked to original sources
PubMed1988

Are BAEP and MLR suited for the study of a hypothetic peripheral selective attention effect?

BAEPs and MLRs for clicks were recorded for situations of selective attention, ignoring stimuli and mental arithmetic. Certain studies have shown no attention effect on these evoked potentials, but several others have shown reduction of latency and increase in amplitude under selective attention. Our study finds no significant difference in latency or amplitude for BAEP waves I, III and V, nor in Na or Pa latency or NaPa amplitude for MLR. What we know anatomically of cochlear innervation, particularly efferent innervation, would seem to show that efferent projection is basically onto the outer hair cells which have been little if at all explored by BAEPs and MLRs under standard conditions. A study of outer hair cell functioning under various attention situations would be needed in order to find any peripheral selective attention effect.

Acoustic Stimulation↗
PubMed1987

Psychological factors affecting outcome of treatment after transcutaneous electrotherapy for persistent tinnitus.

We used transcutaneous electrotherapy to treat 27 patients with persistent tinnitus. Each patient was tested with the short form of the Minnesota Multiphasic Personality Index test (MMPI) prior to the commencement of treatment. The "unimproved" group of patients (n = 15) showed higher pretreatment scores for depression (P less than 0.05), psychasthenia (P less than 0.05) and schizophrenia (P less than 0.02). Our findings indicate that patients having significantly pathological scores on at least one of these three scales will fail to benefit from treatment. These findings also show that there appear to be psychological prognostic factors that can be used to evaluate patients receiving transcutaneous electrotherapy for persistent tinnitus.

Adult↗
PubMed1987

Virus expression. EGF and transferrin receptors in human papillomas.

Thirty five non regressing cutaneous and mucosal human papillomas were studied for the expression of EGF and transferrin receptors by indirect immunofluorescence on frozen sections. The lesions were also examined for the presence of human papillomavirus (HPV) DNA by in situ-hybridization with biotinylated probes and viral capsid antigen. The mapping of EGF and transferrin receptors was modified in cutaneous lesions with drastic viral cytopathic effects and was enhanced in mucosal lesions mainly in laryngeal papillomas, which are poor virus producers. The greatest increase in EGF and transferrin receptor reactivity was observed in the group of mucosal lesions in which viral DNA was more frequently detected than viral antigen. This suggests that viral DNA may play a role in basal cell stimulation. Moreover some of these lesions with dense inflammatory reactions showed DR antigen expression by epithelial cells. Our findings indicate that epithelial cell activation in papillomas might be modulated by other factors than HPV such as mediators of the local immune response.

Adolescent↗
PubMed1987

Effect of stimulus intensity variation on brain-stem auditory evoked potentials: comparison between neonates and adults.

Brain auditory evoked potentials (BAEPs) were recorded from 40 adult subjects and 40 neonates at 80 and 60 dB (nHL) to compare the effects of stimulus intensity variation on waves I, III and V and on intervals I-III, III-V and I-V. The results show that the changes in latency for wave, I, I-III and I-V intervals are significantly greater in neonates than in adults. So the effects of stimulus intensity variation on BAEPs are different in neonates and in adults and a major effect is in the peripheral auditory mechanism.

Acoustic Stimulation↗
PubMed1987

Epithelial expression of HLA-DR antigens in laryngeal papillomas with a dense inflammatory reaction.

Thirty six laryngeal papillomas taken from 11 children and 10 adults were investigated with an indirect immunofluorescence technique for the occurrence of T cell subsets, Langerhans cells and HLA-DR antigen using specific monoclonal antibodies. A mild local cellular immune response was preferentially associated with juvenile laryngeal papillomas, whereas a more intense inflammatory reaction with T8 cell infiltration and large amounts of Langerhans cells in the chorion and the epithelium was observed in adult lesions. Some lesions either from adults or children characterized by high densities of lymphoid and dendritic cells exhibited the expression of DR antigen by epithelial cells. This result may suggest either a role of lymphokines released by activated T cells or a direct effect of viral infection on epithelial cells inducing DR antigen in laryngeal papillomas.

Adult↗
PubMed1987

Brainstem auditory evoked responses alteration in twin neonates.

The authors obtained BAER recordings for 20 premature twins and 20 premature non-twins. The two groups were comparable as to conceptional age (36-37 weeks), gestational age, chronological age, birthweight, sex ratio and head size. The results showed a prolongation of the central conduction time (I-V interval) in the premature twins. This may be due to the intra-uterine growth retardation of twins.

Birth Weight↗
PubMed1987

[Complete excision of acoustic neurinoma. Preservation of the facial nerve and hearing].

Using microtechniques, total removal of acoustic neuromas with facial nerve preservation is possible today in most cases. The next barrier of operative treatment is hearing preservation which is routinely attempted, with the help of intraoperative brainstem auditory evoked responses monitoring. The present series deals with 176 operations performed sub-occipitally in 159 patients from 1970 up to 1985. Twelve patients were operated upon 29 times. According to the W.T. Koos classification, there were 16 type II, 39 type III and 121 type IV neuromas. Ten patients died postoperatively. In seven of these, death was related to surgery, in two it was caused by respiratory failure. In the last patient unexplained sudden death occurred. 169 patients had no facial weakness preoperatively, in 158 of these the facial nerve was anatomically preserved (93.5%). Facial nerve function was judged by evaluation of function of face at least 12 months after operation. Up to 36 months after surgery, a good facial result may be expected in cases where the facial nerve was macroscopically spared at completion of removal. Functional results have been reviewed in 151 patients according to the J.W. House's International Evaluation System, with an excellent or good result in 66 (44%), fair in 65 (43%), bad or poor in 20 (13%). The anatomical preservation of the cochlear nerve could be achieved in 80 patients of the group of 169 in whom the auditory function had not been damaged by a previous operation. In fact, the auditory function preservation could be reasonably attempted in 79 patients: showing a hearing loss below 70 dB on tone audiometry, whatever may be the result of speech discrimination score. 59 patients (75%) of this later group had their auditory nerve preserved, 14 (18%) showed preserved hearing function postoperatively, 10 of these with a speech discrimination score over 50%. Two of these showed an improvement of preoperative hearing, two others showed a total recovery of hearing function after removal.

Adolescent↗
PubMed1986

Laryngeal papillomas: local cellular immune response, keratinization and viral antigen.

Various parameters of the local cellular response have been studied in 16 laryngeal papillomas from ten patients with recurrent papillomas as well as normal control laryngeal and tracheal tissue by indirect immunofluorescence on frozen sections using monoclonal antibodies specific for T-cell subsets, Langerhans cells (LC) and HLA-DR antigens. Keratinization was investigated with a monoclonal antibody KL1 recognizing an acidic 56.5 Kd keratin, which is a marker of suprabasal cells in stratified squamous epithelium and is absent from the basal layer. The presence of viral antigen was detected with a rabbit antiserum raised against SDS-dissociated purified virus. A mild inflammatory response was observed in most biopsies. Cytotoxic/suppressor T-cells were the predominant cells found in the lesions. Compared with normal epithelium, the number of LC was dramatically reduced in the papillomatous epithelium. High densities of HLA-DR-positive cells were found mainly in the corium. The keratinization process was disturbed in most specimens in that both basal and suprabasal compartments reacted positively with the KL1 monoclonal antibody. Viral antigen was present in the nucleus of very occasional epithelial cells in some samples.

Adolescent↗
PubMed1986

[Montgomery's tube in laryngotracheal stenoses in children (11 cases)].

Because of the fragility of the laryngotracheal tree in children, and the serious consequences on function of any chondritic lesion or even mucosal edema, overall endoscopic treatments combined with prosthesis insertion are preferred to any surgical procedure. Eleven cases of laryngotracheal stenosis are reported where treatment involved use of Montgomery's calibrated tube.

Child↗