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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In serous and secretory otitis media a reduction of bone conduction frequently exists besides the loss of air conduction. In 304 audiograms of ears with serous and viscous fluid in the middle ear there was a depression of the bone conduction between 15 and 40 dB in 40%. This bone conduction loss was reversible after the aeration of the tympanic cavity. That means that we deal with a false nerve deafness in many of these cases.
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PMID:[Bone conduction changes in secretory otitis media (author's transl)]. 14 76

The authors present the preliminary results of a range of their aero-space medicine studies, carried out in hypobaric chamber, in simulated flight and at different atmospheric pressures, to asses the tubal function in normal hearing people. The tympanometric determination through a Z072 Madsen inpendenzometer in static and dynamic conditions of barometric depression gave a clear and exact indications about the impedence variation capacity of the middle ear in similated flight, giving homogenous data which allow the use of this method in flying recruitment aptitude test routine.
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PMID:[Behavior of the impedance of the middle ear and of the stapedius reflex under static conditions of barometric depression]. 60 Apr 59

Changes in behavior and electrical activity of primary vestibular neurons were observed following injection of lidocaine hydrochloride into the middle ear of cats. After injection the cats exhibited head and ocular nystagmus, head and neck deviation and pupillary changes. Mean preinjection resting discharge rate for first order vestibular neurons was 46.0 spikes/sec. Two hours after lidocaine application the resting rate decreased to a mean of 22.2 spikes/sec and then recovered to 43.0 spikes/sec four hours, and 47.4 spikes/sec six hours after the experimental treatment. The increment sensitivity (increased rate of firing) of horizontal canal neurons to constant angular acceleration for the control period was 2.0 extra spikes/sec/deg/sec2; two hours after the application, 70% of the recorded neurons were unresponsive to angular acceleration or tilt. The sensitivity after four hours was 1.0 spikes/sec/deg/sec2 and 2.1 spikes/sec/deg/sec2 at six hours. The distinct depression of sensitivity by lidocaine at four hours compared to normal mean resting rate at this time suggests these functions may be governed by two modes of action in the receptor or first order afferents.
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PMID:Response of first order vestibular neurons to lidocaine hydrochloride. 62 8

A previously healthy middle aged man died following a 6 month illness which presented with middle ear symptoms, apparently resolved, and then 2 months later manifested as encephalitis. The illness was characterized initially by depression and intellectual deterioration. No family member or working associate was affected. The clinical diagnosis of viral encephalitis was confirmed by brain biopsy but no virus was isolated in the laboratory. Numerous intracisternal toroidal virus-like particles were demonstrated by electron microscopy in the perikarya and dendrites but not in glia. The particles resemble, but are not identical to, the oncornaviruses associated with spontaneous and induced murine neoplasms. The resemblance of these structures to the intracisternal toroidal type "A" virus of murine leukemia is noted and other possible causes for this atypical meningoencephalitis are discussed.
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PMID:Meningoencephalitis with toroidal virus-like particles. 115 39

The respective effects of pentobarbital-sodium, enibumal-sodium, urethane, urethane-chloralose and lidocaine on the function of the acoustic middle ear reflex in the rabbit were studied. The response of the middle ear muscles was measured by recording changes in both ears' acoustic impedance when the reflex was elicited by applying pure tone stimuli (2,000 Hz) to the two ears one at a time. In that way both the crossed and the uncrossed reflexes were studied. All the drugs were found to depress the reflex in such a way that a higher sound intensity was required after administration to achieve the same impedance change as before. The effect of the anesthetics was roughly proportional to their known anesthetic power. Lidocaine produced only a slight depression of the reflex. The crossed reflex showed a greater susceptibility to the general anesthetics than did the uncrossed reflex which suggests a greater complexity of the crossed reflex. Because the method of recording the reflex response does not require any surgery and is equally well applicable in unrestrained rabbits and in humans, it is suggested as a way of testing the effect of drugs on the central nervous system.
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PMID:Effect of central depressants on the acoustic middle ear reflex in rabbit. A method for quantitative measurements of drug effect on the CNS. 118 78

The structure and evolution of the mandible, suspensorium, and stapes of mammal-like reptiles and early mammals are examined in an attempt to determine how, why, and when in phylogeny the precursors of the mammalian tympanic bone, malleus, and incus (postdentary jaw elements and quadrate) came to function in the reception of air-borne sound. The following conclusions are reached: It is possible that at no stage in mammalian phylogeny was there a middle ear similar to that of "typical" living reptiles, with a postquadrate tympanic membrane contracted by an extrastapes. The aquamosal sulcus of cynodonts and other therapsids, usually thought to have housed a long external acoustic meatus, possibly held a depressor mandibulae muscle. In therapsids an air-filled chamber (recessus mandibularis of Westoll) extended deep to the reflected lamina and into the depression (external fossa) on the outer aspect of the angular element. A similar chamber was present in sphenacodontids but pterygoideus musculature occupied the small external fossa. The thin tissues superficial to the recessus mandibularis served as eardrum. Primitively, vibrations reached the stapes mainly via the anterior hyoid cornu, but in dicynodonts, therocephalians, and cynodants vibrations passed mainly or exclusively from mandible to quadrate to stapes and the reflected lamina was a component of the eardrum. In the therapsid phase of mammalian phylogeny, auditory adaptation was an important aspect of jaw evolution. Auditory efficiency, and sensitivity to higher sound frequencies were enhanced by diminution and loosening of the postdentary elements and quadrate, along with transference of musculature from postdentary elements to the dentary. These changes were made possible by associated modifications, including posterior expansion of the dentary. Establishment of a dentary-squamosal articulation permitted continuation of these trends, leading to the definitive mammalian condition, with no major change in auditory mechanism except that in most mammals (not monotremes) the angular, as tympanic, eventually bcame a non-vibrating structure.
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PMID:Evolution of the mammalian middle ear. 120 24

The immune system is active in the tubotympanum and some middle ear diseases might be partially or exclusively immunologically mediated. However, the effect of an allergic reaction on the tubotympanic cilia remains to be elucidated. The response of normal tubotympanic cilia from the guinea pig was investigated in an in vitro experimental system to evaluate ciliary responsiveness without the influence of secretions. Mucosal samples were obtained from three different tubotympanic locations (Eustachian tube, and middle ear close to the tube (proximal site) and more distal to the tube (distal site)). Each mucosal sample was cultured in 2 ml of RPMI 1640 and 1 ml of heparinized venous blood from a nonallergic human subject, a patient with ragweed-sensitive nasal allergy, or 3 patients with Dermatophagoides farinae-sensitive nasal allergy. One microgram of D. farinae extracts was added in each chamber to evoke an in vitro allergic reaction, and the ciliary activity of the most active cell in each culture was monitored for up to 120 min. When D. farinae extracts were added into the chamber containing blood from subjects without sensitivity to D. farinae, no changes were induced in ciliary activity throughout the examination. When the same dose of allergens was added into the chamber containing blood from D. farinae-sensitive subjects, ciliary excitation was induced in the culture from the Eustachian tube and the proximal site. The peak and plateau of this phenomenon were observed at 30-40 min after the addition of the allergen, and a gradual slowdown to the baseline level was observed after the plateau. No ciliary depression was induced by an allergic reaction in the culture from the Eustachian tube or the proximal site. Such ciliostimulatory effects were correlated with D. farinae induced-percent histamine release from whole blood. In the cultures from the distal site, however, a gradual ciliodepression followed the peak of ciliary excitation. In conclusion, an in vitro allergic reaction affected the ciliary activity in the distal site, but such ciliary dysfunction was not observed in the Eustachian tube or the proximal site during such a reaction.
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PMID:Ciliary activity in the tubotympanum during type I allergic reaction. 184 64

The mucosa lining the cavity of the middle ear of sea lions contains a complex network of venous channels and sinuses. During dives the pressure within the middle ear may be equalized with that in the external auditory meatus either by the distention or depression of the mucosa due to the presence or absence of blood in the sinuses.
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PMID:Pressure regulation in the middle ear cavity of sea lions: a possible mechanism. 594 Aug 98

Although microtia occurs in only 1:7000 to 8000 births, this major congenital ear deformity can result in significant psychological trauma for the affected child. Reconstruction of this complex deformity represents one of the greatest challenges to the reconstructive surgeon. Based on the pioneering work of Tanzer and Brent, the techniques have matured to the point that consistently good results can be obtained and many of the resultant problems associated with the deformity avoided. In classic microtia, a sausage-shaped vestige is made up of a rudimentary lobule and various additional remnants. The external canal is usually absent. Where hearing is normal in the opposite ear, it is not necessary to reconstruct the middle ear or external canal on the affected side, and these procedures may compromise the result of the external ear reconstruction. The staged reconstruction of the microtic ear, which can begin at 5 years of age, involves: placement of an autogenous cartilage framework; rotation of the lobule, formation of a conchal depression and tragal reconstruction; limited elevation of the helical rim; and minor final adjustments. The cartilage is placed during the first stage to make maximal use of the non-scarred elastic skin in the area of the skin pocket. This allows better splicing of the lobule in the second stage. The use of a very thin skin flap over the framework allows heightened definition of cartilage detail, better skin-cartilage coaptation, and at appears to play a vital role in preventing late deformation of the cartilage framework.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reconstruction of the microtic ear. 648 90

Ventilation and drainage are the two essential intrinsic functions of the sinus. Both of them are dependent upon the permeability of the ostium, whose caliber is extremely variable with respect to anatomical factors, and dynamic factors associated with the vasomotricity of the mucous membrane. In many subjects the ostial permeability is precarious, thus explaining the frequency of inflammatory sinus reactions. These are due, as the level of the middle ear, either to a transostial inoculation of pathogenic germs creating a microbial sinusitis, or to an ostial obstruction responsible for a hypoxia, a hypercapnia, and a local depression creating a a vacuo sinusitis. The second situation leads to conditions that are favorable for the development of the first and vice versa.
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PMID:[Physiology of the sinuses. Physiopathology of sinusitis]. 665 Jan 46


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