A hydrodynamic model of labyrinth to study the stimulation of perilymph compartments by audioprostheses.

CONCLUSIONS: The hydrodynamic model of the labyrinth spaces (LHM) is a useful tool for research on implantable audioprostheses, in particular to develop suitable actuators using MEMS technology (micro-electromechanic machine system). It has other potential applications for auditory research. OBJECTIVES: The energy reaching the labyrinth fluids is crucial information for developing prostheses to substitute the tympanic-ossicular system because adequate stimulation of the cochlear partition is essential. However, in vivo measurements in human ears are not currently available. Therefore a model of the normal labyrinth resembling its hydrodynamic properties becomes a valuable tool. It could allow comparison of different processing systems, algorithms and transducers, to develop new audioprostheses and improve their effectiveness and efficiency. MATERIALS AND METHODS: This work presents one LHM that emulates the conduction of the stimuli from the stapes footplate through the labyrinthine fluids, including its dimensions and physical properties, and some examples of measurements of perilymph stimulation by different audioprostheses and algorithms. RESULTS. As shown in the reported examples, this LHM provided effective measurement of acoustic stimulation across the whole human auditory frequency and intensity spectrum. Air-delivered and direct stimulation methods are possible. This provided convenient information for the actuator development and allowed comparison between different prototypes, stimulation patterns and algorithms.

Effectiveness assessment of otosclerosis surgery.

CONCLUSIONS: The epidemiological characteristics of otosclerosis and its treatment in Andalusia resemble those of other populations with similar socioeconomic levels. Two complementary approaches, such as questionnaires and pure-tone audiometry, are required to assess the effectiveness of otosclerosis surgery (OS) reliably and precisely. OBJECTIVES: We describe a new method to assess effectiveness in OS. It is based on the results of pure-tone audiometry and a specially designed quality of hearing questionnaire (QHQ). The objectives of the study are: (i) to report the general epidemiologic profile of otosclerosis in Andalusia; (ii) to study the effectiveness of OS in our community using conventional methods; and (iii) to study the outcomes of OS using the QHQ and to compare them to those obtained using conventional methods. MATERIAL AND METHODS: All 31 hospitals in the public healthcare system of Andalusia were studied. They were graded into four groups using a specially designed grouping system. The data were obtained from the minimum basic dataset. The prevalence of otosclerosis in Andalusia was calculated from the incidence data, the duration of the disease and life expectancy. To assess the effectiveness of OS, 475 clinical records from 15 hospitals representing all 4 groups were analysed. Effectiveness was assessed by conventional methods, using data obtained from pure-tone audiometry, and by using version 1.02 p of the QHQ. RESULTS: The incidence of clinical otosclerosis was 5.67 patients/100,000 inhabitants/year. The calculated prevalence was 0.287%. The number of cases increased progressively during the study period (p<0.001). The 15-45-year age group was the largest (62.2%) and 68.4% of patients were females. The most frequent type of otosclerosis was estapediovestibularis (fenestral), non-obliterative (91.8%). Only 48 cases (2.3%) of cochlear and 45 (2.2%) of obliterative otosclerosis were reported. The most frequently employed therapeutic procedures were stapedectomy and stapedotomy (75.70%). The average total and preoperative lengths of stay were 3.59 and 1.04 days, respectively. There were significant differences between the different types of otosclerosis. Improvement in the air-bone gap was 15.37+/-1.19 dB (n=164) and the overclosure or operative damage was 0.49+/-0.85 dB (n=164). A gap improvement of 10-40 dB was observed in 61.4% of patients. The > 65 years age group showed the best gap improvement but the largest variability. The quality of hearing measured by the QHQ showed that, in general, a better gap improvement was associated with a higher quality of hearing (Pearson correlation r=0.183; p<0.05). The 15-45-year age group had the worst gap improvement but, in contrast, the better quality of hearing.

Traditional birth attendants in Mexico: advantages and inadequacies of care for normal deliveries.

In Mexico, traditional birth attendants (TBAs) are an essential resource for health care, especially in small rural communities where they attend approximately 45% of all deliveries. Both rural and urban women seek care with the TBAs because, amongst other things, they share the same cultural codes. In this study, qualitative and quantitative methods were used to analyze the concepts, resources and process of care during birth in rural areas of the state of Morelos. Results show that the socio-economic characteristics of the TBAs are similar to those of the patients, that they share the same precarious living conditions, and the resources to which they have access for providing care during births. When choosing a TBA as a health care provider, both the economic aspect and the importance of a shared symbolism come into play. We observed advantages in some of the traditional practices which should be incorporated into the medical system, for example protection through the massage of the perineum at the moment of expulsion. Nevertheless, there are inadequacies for which the implementation of training programs is fundamental, before articulate primary care programs using the TBAs can be promoted.

Cisplatin, 5-fluorouracil, and high-dose folinic acid in patients with advanced unresectable head and neck cancer.

For patients with advanced, unresectable head and neck (HN) cancer, surgery and/or radiotherapy are the standard treatments but have poor results. A phase II trial of a continuous infusion of cisplatin, 5-FU, and high dose folinic acid (PFL) as induction chemotherapy in patients with previously untreated, locally advanced HN cancer was performed in an attempt to confirm the encouraging results reported by Dana Farber investigators using an identical regimen. Forty-five consecutive patients with unresectable HN cancer were treated every 28 days with a continuous infusion of cisplatin 25 mg/m(2)/day (days 1-5), 5-FU 800 mg/m(2)/day (days 2-6), and folinic acid 500 mg/m(2)/day (days 1-6). After three courses of chemotherapy, patients were treated with surgery and/or radiotherapy. Objective responses were observed in 26 of 38(69%) evaluable patients with 14(37%) clinical complete responses. Grade III-IV toxicity was important and consisted mainly of mucositis and neutropenia that were found in 47 and 18%, respectively , of patients after the first course. There was one toxic death. PFL is an active, toxic induction regimen for far-advanced HN cancer, yielding a response rate in the range of the widely used cisplatin and 5-FU (PF) schedule; a comparative trial is warranted before concluding that PFL is superior to the latter combination.

Effects of experimental renal insufficiency on the osmotic pressure and the biochemical composition of perilymph.

The biochemical effects of experimental renal insufficiency produced by bilateral nephrectomy on perilymph were studied. Rats were used for the experiments; measurements were carried out at various intervals after nephrectomy. Statistically significant changes in perilymph (osmolality, Na, K, Cl, and urea), and serum (osmolality, urea and creatinine) were found. These findings represent a marked labyrinth alteration, and may partly explain the pathophysiology of labyrinthine disturbances in chronic renal disease.

Time sequence of degeneration pattern of the organ of Corti after acoustic overstimulation. A light microscopical and electrophysiological investigation in the guinea pig.

In order to obtain information about the sequence of events leading to degenerative changes in the cochlea after acoustic trauma, a systematic LM study was performed in the guinea pig organ of Corti. The results were correlated with measurements of CAP N1 thresholds from the same animals. Twenty pigmented guinea pigs were used in the study. Ten of these animals were exposed to a 3.85 kHz pure tone with an intensity varying between 108 and 120 dB SPL for 22.5 to 360 min and were sacrificed after 4 weeks. Eight animals were exposed to 120 dB SPL for 22.5 min and sacrificed at regular intervals after exposure, viz. 5 min, 4, 24 h and 5 days. Prior to sound exposure the animals in the 4-week group were implanted with a permanent round window electrode for measurements of CAP N1 thresholds. The study indicates that the degeneration and reparative processes are not entirely completed after 4 weeks. The development of holes in the reticular lamina may result in further degeneration of cells bilateral to the initial maximum damage. Darkly stained cells seem to be activated in the reparative process in the organ of Corti. Local appearance of dendritic macrophages in the organ of Corti indicate the existence of a local mechanism for disposal of degeneration products from the organ of Corti. The retrograde degeneration of radial nerve fibres seems to be closely associated with that of the pillar cells. A close correlation between structural hair cell damage and CAP N1 threshold shift was found in the region of the organ of Corti corresponding to the exposure frequency. The TS 5 min, 4 h and 24 h after exposure showed a close correlation with swellings in the afferent nerve endings below the IHC in the area of maximum damage and basalwards.

Effect of gentamicin on the carbohydrates of the vestibular end organs: an investigation by the use of FITC-lectins.

The effect of gentamicin on the glycoconjugates in the vestibular end organs is demonstrated using FITC-lectins. Five milligrams of gentamicin dissolved in 0.1 ml. saline was injected in a single dose into the middle ear of adult guinea pigs. Seven days after the injection, the fluorescent reactivity of Wheat germ agglutinin (WGA), Abrus precatorius agglutinin (APA), Concanavaline A (Con A), and Latyrus odoratus agglutinin (LOA) was decreased in the apical epithelial cell surface as well as in the gelatinous layer of the otolithic membrane of the maculae. In the cupula of the crista ampullaris, the reactivity for WGA and Con A was reduced. The otoconia, however, showed no detectable changes. This indicates that gentamicin may induce an altered carbohydrate metabolism resulting in a decrease of N-acetyl-glucosamine, mannose, galactose and glucose in the glycocalyx lining the epithelial cells as well as in the gelatinous layer of the otolithic membrane or cupula in the vestibular end organs.

[Analysis of the blood-labyrinthine barrier in a model of progressive osmotic change]. / Análisis de la barrera hematolaberíntica en un modelo de cambio osmótico progresivo.

The AA. working with Gerbils (Meriones unguiculatus) experimentally deprived of their kidneys attempt to find out the behaviour of the BLB. The study was accomplished through the dynamic examination of the osmolality and ureic concentrations of the perilymph, the blood and in spinal fluid as well. Furthermore the role of the BLB in the origin of labyrinthine osmotic variations, as provocative cause of the inner ear pathology, is contemplated.

[The sensorineural component of hearing loss associated with cholesteatoma]. / El componente neurosensorial de la hipoacusia asociada al colesteatoma.

Patients with cholesteatoma often suffer neurosensorial hearing loss with variable bone conduction thresholds. Its origin is debated and has been attributed to the ototoxicity of topical drugs, immune reactions, effects of ototoxic antibiotics applied to the ear, etc. A selected series of 50 patients who underwent surgery for chronic ear disease due to cholesteatoma in our ENT department were studied to evaluate the possible origin of the bone conduction component of hearing loss. Different clinical, audiological, and surgical aspects were analyzed, including cholesteatoma site and extension, age, sex, evolution of the symptoms, pure tone audiometry data, middle ear involvement, the operation performed, and the occurrence of complications. Bone conduction thresholds were reported as pure tone differential thresholds (affected vs non-affected ear). A specific cholesteatoma-related neurosensorial hearing loss was observed that might lead to irreversible hearing loss. Neurosensorial involvement seems to be related mainly to the duration of symptoms, type of surgery, certain specific clinical aspects, and complications.

[Small-cell carcinoma of the larynx]. / Carcinoma de células pequeñas de laringe.

Primary small-cell (also known as oat-cell) neuroendocrine carcinoma of the larynx is an infrequent tumor. We report a case of epiglottic oat-cell carcinoma in a 57-year-old man. Its association with other malignant neoplasms and aggressive behavior in spite of treatment are discussed.

Un análisis del problema ético y legal del tratamiento del cáncer cervicouterino en mujeres embarazadas: [revisión] / Ethical and legal problem in the treatment of cervical cancer in pregnant women: [review]

Se analiza el problema ético y jurídico del tratamiento del cáncer cervicouterino en mujeres embarazadas. Se realizó una revisión del tema, de las leyes chilenas y de algunas normativas europeas para después analizar la aplicación de los principios de No Maleficencia, Beneficencia, Autonomía y del Doble Efecto. El tema genera una difícil discusión e interpretación, pues tanto las leyes como los principios son orientadores, pero no explícitos para decidir la conducta más adecuada en cada caso. Lo ideal es preservar la vida materna y fetal, pero hay casos en los que, finalmente, es necesario priorizar una sobre la otra. Corresponde al equipo tratante, la madre, el padre, la familia y la sociedad concordar las conductas más responsables y justas posibles.

Authors analyze the ethical and legal problem about the treatment of cervical cáncer in pregnant women. A review of the Chilean laws and European regulations was made in order to analyze the application of the principies of Non maleficence, Beneficence, Autonomy and the Double Effect. The subject generates a difficult discussion and interpretation since both, law and principies, are guiding but do not give an explicit answer to choose the more appropriate behavior in each case. The goal is to preserve maternal and fetal life, but there are cases in which it is necessary to prioritize one over the other. A consensus between medical staff, the mother, the father, the family and society is necessary for a more responsible and fair decision.

Effects of renal insufficiency on the cochlear absorptive-secretory areas. A morphological study in the Mongolian gerbil.

In order to evaluate the effects of experimental renal insufficiency (RI) on the labyrinthine absorptive-secretory areas (ASA), 54 adult Mongolian gerbils were submitted to bilateral nephrectomy or to sham procedure. At different intervals (3, 6, 9, 12, 15, 18, 21, 24 hours) after the surgical procedures, or during the terminal stage (28 h) the animals were decapitated and both temporal bones were dissected to obtain selected specimens of the cochlear ASA. The specimens were processed and analysed by light and electron microscopy. Structurally, RI induced progressive thickening of the epithelial components (stria, prominentia, sulcus); separation by fluid accumulation between stria and mesodermal layer; and frequent dilatation of intraepithelial vessels. Ultrastructurally, diverse signs were observed parallel to the evolution of the RI. After 12 h a progressive enlargement of the intercellular spaces, which was particularly evident in the stria surrounding the vessels and in the other sulcus, was observed. Its latest expression was a marked widening of the basolateral spaces containing a granular substance. After 12 h the formation of large cytoplasmic perinuclear spaces containing small rounded vesicles, probably secondary to fluid accumulation, could be observed in the marginal cells. After 24 h diverse signs of organellar damage became evident (schedule: mitochondrial swelling, lysosome like figures, myelin like figures). In the terminal stage, a general homogenization of the cytosol was common. The findings suggest a definite re-distribution of fluids in the inner ear. A close relationship between renal dysfunction and labyrinthine microhomeostasis is therefore proposed.

[The endocochlear potential in experimental renal insufficiency]. / El potencial endococlear en la insuficiencia renal experimental.

Endocochlear Potential (EP) was measured in male Wistar rats under control conditions and renal failure produced by means of bilateral nephrectomy. Results show a statistically significant (p less than 0.01) decrease in EP measured in animals with renal failure. This finding is in accordance with the decrease in Na-K ATPase activity found in the cochlea and other structures in human and experimental kidney insufficiency.

[Effects of bilateral nephroadrenectomy on the composition of perilymphatic fluid in the rat]. / Efectos de la nefroadrenectomía bilateral sobre la composición del líquido perilinfático en la rata.

The examination of osmolality and ionic composition of plasma and perilymphatic liquid of nephroadrenectomized rats was performed by systematic methods. Significant increases in osmolality, Na and K concentrations were found in perilymph of nephroadrenectomized animals. The functional importance of these findings is evaluated, and the influence of blood labyrinth barrier and osmotic mechanisms on these results is discussed. Simultaneously, the possibility that similar mechanisms might be involved in the pathogenesis of Meniere's disease is pointed out. A possible route on pathogenical and clinical studies in labyrinth pathology is enhanced.

DC potentials of the lateral wall of the scala media.

We recorded DC potential and resistance changes of the cochlear lateral wall in guinea pigs, using (3M KCl) electrolyte glass microelectrodes. The patterns found for slow penetration showed different potential and resistance characteristics at different segments of the lateral wall. In addition, our findings demonstrate that the monitoring of microelectrode tip resistance is a useful procedure for DC cochlear recordings.

Carbohydrates of the vestibular end organs detected by lectins.

The presence of carbohydrates was investigated in the vestibular end organs of the guinea pig using FITC-lectins. The following sugars have been identified: N-acetyl-glucosamine, galactose, mannose and fucose. In contrast, N-acetyl-galactosamine was not clearly detected. These sugars were suggested to be closely related to the formation and maintenance of otoconia as well as of the cupula. N-acetyl-glucosamine was considered to be the major component of the glycocalyx and also suggested to have a function as an anchoring structure between the epithelial cell and the otolithic membrane or the cupula.

Clinical design and evaluation of the prototype of a new digital audioprosthesis for profound hearing loss: speech recognition aspects.

The design and implementation of the prototype of a digital hearing aid and its computerized fitting interface, followed by a basic preliminary clinical evaluation concerning speech recognition aspects, is reported. The final device is particularly destined to those patients suffering sensorineural hearing losses with recruitment and problems for speech recognition. The prototype is based on the digital signal processor TMS320C30. The host is a personal computer. The primary concept of the processing strategy is the 'integral treatment of acoustic information' within the remaining auditory field of the patient leading to minimum modification of the signal profile. The processing stages include linear amplification, specially designed AD conversion, real fast Fourier transform, 128 multiband single treatment (compression threshold and magnitude of compression), inverse fast Fourier transform, and DA conversion. Compression parameters and pure-tone audiometry data are entered by the computerized fitting interface which also provides real time information of input and output spectral profile. The preliminary clinical evaluation here reported corresponds to a series of 13 patients and it is focused on speech recognition performances. Ten patients had sensorineural hearing loss. Three subjects served as controls. All subjects were studied by an extensive audiological protocol. In 6 patients the prototype improved the maximum intelligibility with respect to unaided hearing reaching levels in the range of 90-100%. In 4 patients using conventional hearing aids, the prototype improved the maximum intelligibility with respect to the previous aided hearing. Values reached the same range as in the former 6 patients. Straightening of the speech audiometry curves was observed in those patients with recruitment. Two controls with previously normal speech recognition showed no worsening and others with conductive deafness reported additional improvement of the responses in noisy conditions with respect to the audioprosthesis in use.