Histophysiological observations on the external auditory meatus,middle, and inner ear of the weddell seal (Leptonychotes weddelli)

The external auditory meatus, middle, and inner ear of the deep-diving Weddell seal (Leptonychotes weddelli) were studied with light microscopic, histological, and histochemical techniques in order to contribute to the open discussion on the orientation of this seal in the darkness of the deep Antarctic seas. The external auditory meatus is characterized by a well-developed venous plexus, single apocrine ceruminous, and numerous holocrine sebaceous glands and an incomplete tube of elastic cartilage. The tympanic membrane is comprised of two layers of radially and concentrically arranged collagen fibers and by elastic fibers which are concentrated in the outer part of the ear drum. The tympanic cavity is lined by a pseudostratified prismatic ciliated epithelium with goblet cells; a plexus of wide venous vessels marks the subepithelial lamina propria. The cochlea is about 10 mm high and forms about two and a half turns. The richly pigmented stria vascularis is well vascularized, while the cell-rich prominentia spiralis contains only single small blood vessels. The organ of Corti contains one row of inner and three rows of outer hair cells. Cells of Hensen, Claudius, and Boettcher are present. The basilar membrane is of comparatively uniform simple structure and is composed of abundant glycoproteins, proteoglycans, collagenous fibers, and the loose tissue of the tympanal layer. The spiral ligament is built up by abundant proteoglycans and a complex system of radial and concentric collagen fibers; close to the osseous wall of the bony cochlea it contains fine elastic fibers. The inner zone of the osseous wall of the cochlea strikingly contains hyaline cartilage. The thin lamina spiralis ossea is covered by a limbus spiralis with interdental cells secreting the lamina tectoria, which has a fibrous texture and contains glycoproteins and negatively charged components. J. Morphol. 234:25–36, 1997. © 1997 Wiley-Liss, Inc.     

Staphylococcus schleiferi subsp. coagulans subsp. nov., isolated from the external auditory meatus of dogs with external ear otitis

A new subspecies, Staphylococcus schleiferi subsp. coagulans, was isolated from the external auditory meatus of dogs suffering from external ear otitis and is described on the basis of studies of 21 strains. Phenotypic studies showed that these strains are more closely related to Staphylococcus intermedius than to other staphylococci, but DNA hybridization studies indicated that they are closely related to Staphylococcus schleiferi N850274T. On the basis of biochemical distinctiveness (positive test tube coagulase test and different carbohydrate reactions) and the etiological importance (frequent isolation from otitis specimens from dogs) of these strains, we propose to classify them as a subspecies of S. schleiferi. The strains of this new subspecies are coagulase tube test, beta-hemolysin, and heat-stable nuclease positive but clumping factor negative. A simple scheme for the differentiation of S. schleiferi subsp. coagulans from the other coagulase-positive staphylococci is presented. The type strain is GA211 (= JCM 7470).     

Computed tomography of the temporal bones in children with developmental anomalies of the external and middle ear]

Computed polypositional high-resolution tomography (CT) was provided to 45 children with dysplasia of the external acoustic meatus (EAM). The computed tomograms were analyzed in accordance with the scheme which included the evaluation of the following structures: atresia or stenosis area, pneumatized mastoid process, tympanic cavity, ant rum, osteal opening of the Eustachian tube, chain of auditory ossicles, windows of the labyrinth, internal ear, facial nerve canal, and large vessels. Preoperative CT of the temporal bones allows for the evaluation of the above-listed structures, which is of paramount importance for the planning of the patient management policy. Also, CT enables the assessment of the risk of surgical intervention associated with a potential injury to the facial nerve, large vessels, and temporomandibular articulation. CT is to be an indispensable diagnostic modality for examination of children presenting with EAM dysplasia.     

The temperature of the air within the external auditory meatus compared with esophageal temperature during anaesthesia and surgery

• 1.1.|Air temperature within the external auditory meatus, sensed by a thermistor insulated from the walls of the aural canal, was compared with the temperature recorded from a probe in the esophagus in patients under general anaesthesia.
• 2.2.|In the first study of 14 patients, aural temperatures at the time of induction of anaesthesia were more than 3°C lower, and the changes during surgery were more variable, than those recorded from the esophagus.
• 3.3.|In a second study of 35 patients in which heat loss from the external ear was reduced by ear protectors, there was also a poor correlation between temperatures of the ear and esophagus. Aural temperature was initially lower and rose over time in most cases whereas esophageal temperature generally decreased.
• 4.4.|These results suggest that air temperature within the aural canal is not a useful estimate of deep body temperature since it reflects mainly skin temperature.

     

Acidocillin concentration in middle ear exudate]

Acidocillin levels were determined in the middle ear exudates and serum of patients with acute exudative otitis media after oral administration of the drug. Acidocillin rapidly diffused exudate into the ear and its level in the exudate in 1 hour was 0-1.7 gamma/ml. At the same time the serum levels ranges within 4 to 25 gamma/ml. acidocillin remained longer in the ear exudate than in the serum. In 12 hours 0.2 to 1.3 gamma/ml of acidocillin was still found in the exudates, while there was no antibiotic in the serum.     

Atresia of the external acoustic meatus in prehistoric populations

A case of atresia of the external acoustic meatus is presented from a prehistoric Late Woodland site in Iowa. The affected individual was a female aged 30 to 40 years. The left temporal bone displayed a thin bony plate occluding the external acoustic canal. No evidence of middle ear or inner ear malformation was observed on the axial tomographs, although the external canal was shortened. The individual is diagnosed as having a mild case of congenital atresia. The report extends the geographical and temporal distributions of this archaeologically rare condition.     

湿型外耳道分泌物的菌群结构及其药物敏感性分析

人的外耳道中存在种类繁多的微生物。为了解健康人湿型外耳道分泌物中的细菌数量、种类及其对药物敏感性,收集了38例无耳道疾病健康人左、右耳的湿型外耳道分泌物76份。采用分离培养的方法进行平板涂布、菌落计数及鉴定,分析其菌群数量及种类;通过纸片扩散法(Kirby-Bauer纸片扩散法)对分离的细菌进行药物敏感性试验,并利用头孢硝噻吩纸片检测青霉素耐药株产β-内酰胺酶情况。结果显示,88.3%的湿型外耳道分泌物的菌群数量在1×10² CFU/mL～1×10⁶ CFU/mL;共检出细菌20种,其中球菌占97.1%,主要为葡萄球菌;杆菌为2.9%。分离率前4位的细菌为头葡萄球菌、耳葡萄球菌、人葡萄球菌和表皮葡萄球菌,对临床常用的妥布霉素、米诺环素、万古霉素和呋喃妥因等抗生素敏感率达90.0%以上;对复方新诺明和青霉素耐药率相对较高,但低于50.0%。分离得到的132株葡萄球菌中,25株对青霉素耐药,耐药株的β-内酰胺酶阳性率为44.0%。结果提示,从健康人湿型外耳道分泌物中分离的细菌种类多样,以葡萄球菌为主,对临床常用的抗生素有较高的敏感性,但对青霉素、复方新诺明等具有一定耐药性。