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Biomedical subjects

A F Jahn

Publications and source records attributed to A F Jahn.

50 records · Page 3Linked to original sources
PubMed1979

Metastatic tumors in the temporal bone--a pathophysiologic study.

Nineteen temporal bones were examined from 11 patients who had metastatic temporal bone disease from a distant primary. The salient clinical features were: the high incidence of occult temporal bone involvement (7 of the 10 clinically documented cases), the considerable incidence of melanoma (3 of 10) and the variable correlation between clinical findings and pathologic localization of tumor in the temporal bone. Pathologic examination revealed two distinct modes of tumor spread within the temporal bone: 1) vascularosseous (petrous apex, mastoid, middle ear, external canal); and 2) perineural (nerves in IAC branches, labyrinthine endorgans). Every case was involved by one or both or these routes and no case of CSF-borne metastasis to the perilymphatic space was seen. The external canal was involved extensively in spite of an intact tympanic membrane. Since the presence of symptomatic or occult metastases in the temporal bone affects treatment and prognosis, they must be actively sought by the clinician.

Adenocarcinoma↗
PubMed1978

Oncocytic lesions of the larynx.

Eight cases of laryngeal oncocytic lesions treated at Toronto Western Hospital between 1957 and 1977 are reviewed. The typical clinical course was of a benign lesion with prolonged dysphonia. A smaller number with bulkier lesions developed symptoms of airway obstruction. The lesions were supraglottic and cystic. They were excised either endoscopically or via a laryngofissure. The pathologic features support the concept that the lesion represents a metaplasiahyperplasia, and therefore the term 'oncocytic cyst' is preferred to terms which imply a neoplastic process. Three patients with oncocytic cysts had associated squamous dysplasia of the vocal cord. Pathologically this supports the theory of tissue response to chronic irritation, since all three were heavy smokers. Clincially the finding necessitates longterm follow-up with a view to possible squamous cell carcinoma that may arise on the true cords. Follow-up in this series showed no recurrence of symptoms in six of eight cases, two being lost to follow-up.

Adult↗
PubMed1977

Surgery and histopathology of the stapes in osteogenesis imperfecta tarda.

Fourteen stapedectomies were performed on ten patients with osteogenesis imperfecta tarda. Clinically, the footplates were softer and more tenuously fixed than in otosclerosis and floating footplates seemed more common. Stapes and stapes fragments from all 14 operations were examined microscopically. The histopathology of osteogenesis imperfecta was contrasted to that of otosclerosis. We believe that the greater degree of structural disorganization and greater area occupied by resorption spaces clearly distinguish the new bone formed in osteogenesis imperfecta from otosclerosis.

Adolescent↗
PubMed1976

Histologic processing and examination of a 4,000-year-old human temporal bone.

We believe this is the first report of a mummy temporal bone successfully processed by decalcification and serial sectioning. The condition of the bone required modifications of standard processing technique. Examination of the sections revealed evidence of antemortem otitis media and mastoiditis. The technique described should prove useful in otopathological studies of other paleontological specimens.

Histological Techniques↗
PubMed1976

Foreign body granulomas of the ear.

Foreign body granulomas of the ear are seldom looked for, but probably common occurrences. They may be due to exogenous or endogenous material which became implanted in the course of trauma or treatment in the external or middle ear. They provoke inflammation which may be subclinical, clinical, or masked by concurrent infection. They can aggravate chronic infection, initiate acute local inflammation, or jeopardize surgical success. Histologically, the foreign material is seen lying freely or partially encapsulated within chronic inflammatory tissue, in close proximity to foreign body giant cells. Medical treatment can only succeed when the offending agent is surgically removed.

Acute Disease↗
PubMed1975

Nonlamellar new bone formation in the anterior attic recess.

An area of nonlamellar new bone formation was observed in the anterior epitympanic region of 27 randomly chosen human temporal bones. The donors ranged in age from 9 to 80 years and had no evidence of ear disease or systemic skeletal or metabolic abnormalities. The frequency of this finding suggests that it is a normal feather of the human anterior attic recess.

Adolescent↗
PubMed1975

Bone formation in the normal human otic capsule.

Postmoretem examination of undecaicified temporal bones from five patients treated with tetracycline during adult life for unrelated disease showed the uptake of tetracycline label within the endochondral bone the otic capsule. Adult endochondral bone is histologically woven (nonlamellar) in character, and has been assumed to be metabolically inert in the healthy state. The strong perlvascular labelling seen suggests that new bone is normally deposited in the otic capsule and that this new bone is lamellar in character. Continuous new bone formation in the presence of a constant net volume of bone implies that resorption must also occur normally within the otic capsule.

Bone Development↗
PubMedDate not supplied

Lateralization of bone-conducted sounds.

Lateralization of bilaterally applied bone-conducted signals could be accomplished by variation of time (delta t) or intensity (delta I) differences between signals. The task was relatively easy with clicks and with tone pips with short rise times. When rise times were made longer than 1 msec the ability to localize deteriorated, indicating that it depended, within limits, on the steepness of the signal wavefront. Consequently, localization of continuous, pure-tone signals was much more difficult. It improved, with training, after subjects noticed small loudness increments on the side of the leading signal as soon as the phase between signals (delta phi) deviated from zero. Thus, localization of pure-tone signals was aided both by delta phi and delta I. The loudness increments were found to be caused by mechanical interference of ipsi- and contralateral signals at each cochlea, a type of interference peculiar to bone-conducted signals. There were also indications of slight degrees of neural interaction (mutual masking) so long as delta t between short-lasting signals was near zero. The tactile input at the point of contact between vibrators and skin did not significantly contribute to lateralization of bone-conducted signals.

Audiometry, Pure-Tone↗
PubMedDate not supplied

Leiomyosarcoma of the cervical trachea. Report of a case with reconstruction using a latissimus dorsi island flap.

A case of leiomyosarcoma of the cervical trachea is described, detailing clinical presentation, pathologic diagnosis and surgical management. The rarity of this tumor in this location accounted for difficulties in clinical diagnosis and pathologic classification. Surgical treatment involved resection of two thirds of the circumference of the infracricoid trachea, with partial resection of the cricoid cartilage and thyroid gland. The defect was reconstructed using bilateral "butterfly" advancement flaps and a latissimus dorsi myocutaneous island flap. The technique and advantages of the latissimus dorsi flap are briefly described.

Adult↗
PubMedDate not supplied

Computed tomography of the anteverted internal auditory canal.

A symmetric variation in the course of the internal auditory canals, visualized best on axial computed tomographic views with thin sections, was observed in three of 75 patients examined mainly for hearing, vestibular, and facial nerve dysfunction. The incidence may be lower in an unselected population. In coronal section, with either pluridirectional or computed tomography, an anteverted internal auditory canal may mimic the normal configuration of "medial narrowing" because of the effect of partial sectioning of an angled cylinder with a thin beam. The pathologic significance of this finding is uncertain. In the three cases reported, it was associated with adult-onset uni- or bilateral hearing loss. Vestibular function may be compromised but may not be symptomatic. Facial nerve function was not impaired.

Adult↗