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Biomedical subjects

P Fagan

Publications and source records attributed to P Fagan.

At least 37 records · Page 2Linked to original sources

Actinomycosis oto-mastoiditis.

Actinomycosis of the temporal bone is uncommon. There have only been 24 cases previously reported in the English literature. The responsible organism is Actinomyces israelii, an anaerobic filamentous Gram positive bacterium. While the cervico-facial region is the most common site of the disease, involvement of the temporal bone is rare. The diagnosis can sometimes be made clinically by identification of sulphur granules in a glue-like substrate but in all cases involving the temporal bone, the diagnosis has been made at histopathology. Effective therapy consists of surgery followed by the long-term administration of penicillin.

Actinomycosis↗

The readability levels of cancer-prevention materials targeting African Americans.

BACKGROUND: Several studies have examined the readability levels of cancer-prevention materials, but the readability levels of materials targeting African Americans have not been documented. The Cancer Prevention Materials and African-Americans project, funded in 1994 by the Texas Cancer Council, was developed to assess the readability levels and cultural sensitivity of cancer-prevention materials targeting African Americans. METHODS: This study assessed the readability of 100 cancer-prevention materials using McLaughlin's SMOG grading. Illustrations and point sizes were also examined by research staff members. RESULTS: Seventy-two percent of the material contained illustrations and 88% were printed using a 12-point font. An overall mean SMOG grade of 9.32 was found, which suggests that ninth graders can read and comprehend the text. CONCLUSIONS: Although this grade level is lower than those indicated by previous studies, many of the printed materials may not be appropriate for African Americans at high risk for cancer: those with low incomes and little education. Health professionals should focus on decreasing the reading levels of print materials, pretesting audiences to determine their actual reading levels, and examining other factors that influence readability and comprehension.

Adult↗

Schwannoma in the vestibule and cochlea.

Schwannoma of the vestibule or the cochlea is an unusual lesion. In the past, most examples have been found at autopsy or as unsuspected findings at surgery for vertigo. The symptoms of isolated labyrinthine schwannoma may be indistinguishable from advanced Meniere's disease. Magnetic resonance imaging has led to pre-operative diagnosis in some cases. Two cases of schwannoma within the labyrinth from a series of 339 symptomatic acoustic tumours, are presented and the imaging findings are discussed.

Adult↗

Vestibular schwannoma in an only hearing ear.

A vestibular schwannoma in an only hearing ear is a difficult management problem. A case is presented of a patient who had a Nucleus-22 channel device implanted into a nonfunctioning ear and auditory rehabilitation prior to resection of a large vestibular schwannoma in the contralateral ear.

Aged↗

The bony crescent sign--a new sign of facial nerve schwannoma.

Schwannomas of the facial nerve are rare slowly growing lesions that have a predilection for the geniculate ganglion. Radiological evaluation is important in their diagnosis and in the assessment of their extent. In our series of 4 cases the facial nerve schwannoma was seen on high resolution CT as a soft tissue mass bounded anteriorly by a thin rim of bone. This bony crescent sign is a previously undescribed sign of facial nerve schwannoma which appears on the basis of this small series to be strongly indicative of the presence of this tumour. Schwannomas are relatively uncommon intracranial tumours. They most commonly involve the acoustic nerve followed in frequency by the trigeminal nerve. Other cranial nerves are rarely involved. Facial nerve schwannomas occurring within the petrous temporal bone are very rare. Their diagnosis may be missed prospectively even when appropriate CT scans are performed. Even in retrospect the site of abnormality may be difficult to identify, especially if there is an associated middle ear mass such as a cholesteatoma. Lesions occurring in the petrous area are all rare. The differential diagnosis includes cholesterol granuloma, epidermoid, carotid aneurysm and, very rarely, primary and secondary bone tumours. We describe a new sign associated with facial nerve schwannoma on CT, that of a bony crescent. Recognition of this sign makes those tumours arising in the region of the geniculate ganglion easy to diagnose prospectively.

Adolescent↗

NMR structural refinement of a tandem G.A mismatched decamer d(CCAAGATTGG)2 via the hybrid matrix procedure.

A complete relaxation matrix approach employing a matrix eigenvalue/eigenvector solution to the Bloch equations is used to evaluate the NMR solution structure of a tandemly positioned G.A double mismatch decamer oligodeoxyribonucleotide duplex, d(CCAAGATTGG)2. An iterative refinement method using a hybrid relaxation matrix combined with restrained molecular dynamics calculations is shown to provide structures having good agreement with the experimentally derived structures. Distances incorporated into the MD simulations have been calculated from the relaxation rate matrix evaluated from a hybrid NOESY volume matrix whose elements are obtained from the merging of experimental and calculated NOESY intensities. Starting from both A- and B-DNA and mismatch syn and anti models, it is possible to calculate structures that are in good atomic RMS agreement with each other (less than 1.6 A RMS) but differ from the reported crystal structure (greater than 3.6 A). Importantly, the hybrid matrix derived structures are in excellent agreement with the experimental solution conformation as determined by comparison of the 200-ms simulated and experimental NOESY spectra, while the crystallographic data provide spectra that are grossly different.

Base Sequence↗

Magnetic resonance imaging evaluation of cerebellopontine angle tumours.

In the evaluation of tumours of the cerebellopontine angle MRI has a sensitivity and a specificity slightly greater than that of CT. At present it does not appear justified to displace CT as the standard means of investigation of a CPA tumour. The role of MRI is analagous to that of air-CT.

Cerebellar Neoplasms↗

Rupture of the round window membrane.

A perilymph leak into the middle ear through a ruptured round window membrane results in the symptoms of hearing loss, tinnitus and vertigo, either singly or in combination. The case histories of thirteen patients with such a fistula are described, these patients having in common a predisposing incident which had led to a rise of C.S.F. pressure. Symptomatology and the results of investigation are analysed and operative technique and results discussed. While it appears that vertigo uniformly responds very satisfactorily to operative treatment the improvement in hearing loss and tinnitus is more difficult to predict.

Adolescent↗