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Biomedical subjects

P Fagan

Publications and source records attributed to P Fagan.

At least 19 recordsLinked to original sources
PubMed1998

Galvanic stimulation evokes short-latency EMG responses in sternocleidomastoid which are abolished by selective vestibular nerve section.

OBJECTIVE: To describe vestibulocollic responses in sternocleidomastoid (SCM) evoked by transmastoid galvanic (DC) stimulation. METHODS: We studied the averaged responses in the unrectified EMG of SCM to transmastoid galvanic stimulation (5 mA/2 ms) and also to 100 dB clicks. Two patients with Meniere's disease were studied both before and after unilateral selective vestibular nerve section. RESULTS: Transmastoid galvanic stimulation produced a positive-negative biphasic EMG response at short latency in the SCM ipsilateral to the side of cathode placement, which resembled that which followed vestibular activation by loud clicks (p13/n23). Selective unilateral vestibular nerve section abolished this galvanic-evoked response. CONCLUSIONS: Galvanic-evoked vestibulocollic responses can be recorded in SCM. This is a new method of studying vestibular reflex function which may have application in the clinical assessment of vestibular disorders.

Adult↗
PubMed1998

Unusual lesions of the internal auditory canal.

Acoustic neuromata (AN) account for nearly 90 per cent of internal auditory canal (IAC) and cerebello-pontine angle (CPA) tumours. The second most common tumour is meningioma. Rare lesions include primary cholesteatoma, facial neuroma, lipoma, angioma and various cysts. Two cases of IAC tumour are presented, one of hamartoma in which smooth muscle was prominent and the other of lymphangioma. Of interest are the specific clinical and radiological features associated with these lesions.

Adolescent↗
PubMed1998

Cultural sensitivity and readability of breast and prostate printed cancer education materials targeting African Americans.

Cancer prevention materials such as pamphlets, booklets, and fact sheets play a significant role in reducing cancer disparities. Little is documented in the literature about the cultural sensitivity of materials targeting African Americans. The Cancer Prevention Materials and African Americans project was conducted to assess the cultural sensitivity and readability of printed cancer education materials targeting African Americans. Results showed current breast and cancer materials are not written at appropriate reading levels, and only 54% of the breast and 40% of the prostate cancer materials were found to be culturally sensitive. Even though the materials are being developed and disseminated in health fairs, physician offices, barber shops, and other locations, the materials are still not reflective of the African-American populations and do not consider literacy, visual, written messages, and format as factors in their utilization. Future studies should assess the appropriateness of materials for African Americans to promote and prevent cancer in African Americans.

Black or African American↗
PubMed1997

Drill-induced hearing loss in the nonoperated ear.

The reversible hearing loss in the nonoperated ear noted by patients after ear surgery remains unexplained. This study proposes that this hearing loss is caused by drill noise conducted to the nonoperated ear by vibrations of the intact skull. This noise exposure results in dysfunction of the outer hair cells, which may produce a temporary hearing loss. Estimations of outer hair cell function in the nonoperated ear were made by recording the change in amplitude of the distortion-product otoacoustic emissions before and during ear surgery. Reversible drill-related outer hair cell dysfunction was seen in 2 of 12 cases. The changes in outer hair cell function and their clinical implications are discussed.

Acoustic Stimulation↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1994

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↗
PubMed1992

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↗
PubMed1991

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↗
PubMed1989

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↗