A new surface preparation method was devised for assessing intracochlear vessels and sensorineurepithelium. The method is a combination of the conventional osmic acid stained surface preparation method and a surface preparation technique with injection of Prussian blue and decalcification of the cochlea. Such a combination preserves most advantages of each and eliminates many of the disadvantages. To preserve the delicate sensory and nervous structures we examined variations of the preparation, paying particular attention to fixation, staining, and decalcification procedures and solutions. Varying the preparation had a less marked effect on external wall structures than on the basilar membrane; the primary changes consisted of variation in staining contrast. The method proved useful for demonstrating the normal anatomy and pathological changes in cochlear vasculature and in sensorineural and supporting structures of the labyrinth in light and phase contrast microscopy at moderate magnifications.

Animals↗

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The vascular pattern of the chinchilla cochlea.

The vasculature of the chinchilla cochlea was demonstrated with injected Prussian blue contrast. By and large, the vascular pattern is similar to other mammals. The vasculature appears to be richly developed, but separate types of vessels appear to be of small caliber. Particular findings for the chinchilla cochlea were the veins of the scala tympani, formed by a merging of collecting venules, running parallel to the spiral modiolar vein. Furthermore, no vessel of the basilar membrane under the tunnel of Corti was found, and which, when present, is of such great presumed importance for the oxygen supply to the organ of Corti. The scala vestibuli wall appears to be supplied completely arterially, in contrast with that of other mammals. The stria vascularis is broad and well developed, both at the apex and at the basal end.

Angiography↗

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Treatment of acute maxillary sinusitis. IV. Ampicillin, cephradine and erythromycinestolate with and without irrigation.

Six groups, each containing 50 patients with acute maxillary sinusitis, were treated with ampicillin plus nasal decongestant, ampicillin plus irrigation, cephradine plus nasal decongestant, cephradine plus irrigation, erythromycinestolate plus nasal decongestant, erythromycinestolate plus irrigation. The diagnosis was radiologically established and the healing likewise radiologically assessed on the fifth, tenth and fifteenth day. Treatment was given for 10 days. All groups demonstrated a similar radiological healing except cephradine plus nasal decongestant which was inferior to the others. Contrarily, side effects were least frequent in the cephradine groups and most frequent in patients cured with ampicillin. The difficulty in choosing the best treatment is discussed in relation to such factors as therapeutic results, side effects, long-term consequences of antibiotic treatment, establishment of any bacterial etiology and penetration characteristics of antibiotics into the diseased sinus.

Acute Disease↗

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Serological studies in acute maxillary sinusitis.

A comparison was performed between bacteriological and serological findings in 97 patients suffering from acute maxillary sinusitis. A significant titre change (larger than or equal to 2 titre steps) of complement-fixing antibodies to H. influenzae was demonstrated in 15 patients. H. influenzae was demonstrated in aspirated sinus secretions from 7 of these 15 patients. Further, titre changes to Neisseria catarrhalis were demonstrated in 25 patients. No significant titre changes in anti-streptolysin and anti-staphylolysin titres were demonstrated. The results are discussed briefly.

Antibodies, Bacterial↗

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Experimentally induced round window membrane lesions.

This investigation confirmed previous studies indicating that the middle and inner ear of the guinea pig have a pronounced tendency to healing. Middle ear hemorrhage of surgical origin appears to stop quickly in the guinea pig. A surgically created perforation of the round window with or without removal of perilymphatic fluid by suction resulted in a spontaneous healing of the round window membrane in 12/13 animals. Perilymphatic hemorrhage, associated with short post-surgical interval was found in a substantial number of cases. The origin of the perilymphatic hemorrhage is doubtful. Degeneration of the organ of Corti was found in four ears in three animals and appeared to be correlated to the perilymphatic hemorrhage. Electrophysiological measurements appeared to correlate well with the anatomical findings for one animal with very small changes and for three animals with pronounced middle and inner ear pathology. In three additional animals less agreement was observed. In general these animals showed a more pronounced decrease of function than would be expected by the anatomy.

Animals↗

PubMedDate not supplied

The effect of high level sound on hearing sensitivity, cochlear sensorineuroepithelium and vasculature of the chinchilla.

Ten young chinchilla were tested for hearing and then exposed for 8 hours to a 110 dB (SPL) broad-band noise. Post-stimulation recovery was assessed daily until permanent threshold shifts were obtained. Cochlear tissues were prepared in order to allow viewing of sensory cells as well as the vascular supply of the cochlea. Findings included inconsistent displacement of the vestibular membrane, poor injection of a contrast medium into vessels, moderate outer hair cell loss and displaced inner hair cell nuclei. Small basal turn cell damage was accompanied by greater than expected losses for high frequency pure tones.

Acoustic Stimulation↗

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Vascular histology of the guinea pig cochlea.

Detailed histological findings on all the regularly occurring cochlear vessels in the normal guinea pig are presented. Vessels were examined using a surface prepration technique and phase-contrast microscopy. Particular attention was paid to the density of red blood corpuscles, the thickness of the vascular wall, the occurrence of endothelial cells and pericytes, together with their possible influence on the vessel lumen and the existence of perivascular spaces and vessels lacking blood corpuscles. The data are compared with some previous findings of "vascular pathology" following noise stimulation. The possible functional significance of some of the morphological findings is also discussed.

Acoustic Stimulation↗

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Hearing in pop musicians.

Comparatively few previous studies have investigated the hearing of pop musicians. On the average, a surprisingly low percentage (5%) of hearing loss was demonstrated in 160 pop musicians. The present material comprises 83 musicians, with an average exposure of 9 years. Group mean hearing thresholds show only a slight deviation from normal. Age, weekly and total exposure time appear to increase the risk of hearing impairment. In the individual analysis 13-30% were found to have a sensorineural hearing loss, depending upon the definition of hearing loss. Subjects with hearing loss show a discrete impairment in the frequency range 3-8 kHz. Considering the sound levels and the length of exposure, the incidence of hearing loss is suprisingly low. Possible reasons for this are discussed.

Adolescent↗

PubMedDate not supplied

The vascular anatomy of the rat cochlea.

The vascular pattern of the rat cochlea was demonstrated by the aid of Berlin Blue (Prussian Blue) contrast. The vascular anatomy is similar to other mammals. The infrequent occurrence of the vessel of the basilar membrane under the organ of Corti is interesting in respect to its presumed importance for the oxygen supply to the hair cells. In the place where the vessel of the basilar membrane usually lies when present, a large uninjected channel was often seen throughout the cochlea. In the external wall, radiating arterioles supply and collecting venules drain all capillary areas. The vascular pattern of the external wall is well maintained at the basal end but is more sparse in apical parts of the cochlea as in other mammals. The rat cochlea is somewhat more difficult to manipulate than the cochlea in other mammals due to its small size, but the dissection of different parts of the cochlea was achieved without major problems.

Animals↗

PubMedDate not supplied

Cochlear vascular and electrophysiological effects in the guinea pig to 4 kHz pure tones of different durations and intensities.

Round window cochlear microphonic recordings from 33 guinea pigs were obtained prior to and following exposure to a 4 kHz pure tone at levels ranging from 124 dB to 140 dB for 5 to 80 minutes. When electro-physiological evaluation was complete, the animals were killed and tje cochlear tissues prepared using a soft-surface preparation technique. Experimental and control animals were mixed and randomly assessed without prior knowledge of the groups to which the specimens belonged. Histopathological observations were quantified and computer analysed. Statistical analyses suggest that noise exposure results in an overall decrease in blood flow to the cochlea with slight intracochlear increases in flow, perhaps compensatory in nature, to locations corresponding to the 4 kHz exposed region. Results implied that the initial localized hair cell damage known to occur as a result of overexposure to a discrete pure tone is not caused by a decreased blood flow. Relationships between electro-physiological and vascular changes and noise 'dose' are discussed.

Acoustic Stimulation↗

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Immediate noise effects on cochlear vasculature in the guinea pig.

Nine guinea pigs were exposed to a 4 kHz narrow band noise at 120 dB for 30 minutes. The animals were killed immediately following exposure and the cochlear tissues prepared using a soft-surface preparation technique. Experimental and control animals were mixed and randomly assessed without prior knowledge of the groups of which the specimens belonged. The results were analysed by computer. Statistically significant differences in the vasculature between noise-exposed and control animals of a general nature included: more changes in spiral lamina than external wall vessels, more changes in vessels facing perilymph than endolymph, and more changes apically than basally. Results indicate slight intracochlear compensations in blood flow, that could potentially maintain a more constant circulation in regions of the cochlea corresponding to the 4 kHz narrow band exposure noise. Methodological aspects of our inner ear vascular technique as well as some hypothetical explanations regarding the observed changes in the blood supply are discussed.

Animals↗

PubMedDate not supplied

Treatment of acute maxillary sinusitis. V. Amoxicillin azidocillin, phenylpropanolamine and pivampicillin.

One hundred and seventy-five patients with clinical symptoms of acute maxillary sinusitis, the diagnosis confirmed radiologically by mucous membrane thickening and secretion, were consecutively allocated to four different treatment groups: amoxicillin, azidocillin, phenylpropanolamine, and pivampicillin. The cure course was followed up radiologically on days 5, 10, and 15. The outcome of treatment was somewhat more beneficial after 5 days for amoxicillin and after 10 days for azidocillin, but slightly less beneficial with phenylpropanolamine after 10 and 15 days. The numbers of side effects were similar for the different treatment groups. The four treatment modes in question are compared with 19 others previously used in a large material consisting of more than 1000 patients with acute maxillary sinusitis.

Amoxicillin↗

PubMedDate not supplied

Cochlear hair cell and vascular changes in the guinea pig following high level pure-tone exposures.

Noise is thought to exert metabolic and/or mechanical stress on sensory and vascular tissues of the cochlea, the relative influence of the stressors being influenced by the intensity of the noise. Guinea pigs exposed to either of two pure-tone frequencies, 1.33 or 3.85 kHz for 6 hours at intensity levels ranging from 102 dB to 120 dB SPL, were studied for pathological changes in two spiral lamina vessels--the vessel of the basilar membrane (VSBM) and the vessel of the tympanic lip (VSTL). In general, animals sustaining mild to severe degrees of hair cell destruction one month after noise exposure showed little vascular change in the vessels studied. With respect to the vasculature, the concept of a 'critical level' seems to be dependent on exposure frequency, in that only above 117 dB SPL at 3.85 kHz was there any change in the pattern of damage to the spiral lamina vessels.

Animals↗

PubMedDate not supplied

The microsphere surface technique for evaluation of cochlear vessels and circulation. A preliminary report.

A new technique for the evaluation of cochlear microcirculation and cochlear vessels is described. This method is a modification of two previously used techniques, the "soft-surface-specimen method" and the "microsphere method". In this preliminary paper it was found that the microspheres were easily visualised in all cochlear tissues. The absolute and relative distribution of microspheres was calculated. The method appears promising for experimental investigations of cochlear microcirculation.

Animals↗