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Biomedical subjects

R Ramsden

Publications and source records attributed to R Ramsden.

At least 19 recordsLinked to original sources
PubMed2006

Unusual otological manifestations in Camurati-Engelmann's disease.

Camurati-Engelmann's disease (CED) is a rare hereditary disorder affecting mainly the diaphysis of long bones but multiple cranial nerve deficits may also develop secondary to bony sclerosis of their foramina, including visual loss, facial palsy, deafness, vestibular disturbances and sensory deficits along the distribution of the trigeminal nerve. Deafness has been reported in about 18 per cent of these cases due to narrowing of the internal auditory canals caused by bony encroachment on nerves and vessels. We report an extremely rare case of a patient with CED who presented with deafness due to gross abnormalities affecting both middle ear and cochlea. The issues relating to the management of these patients with temporal bone involvement are discussed.

Adolescent↗
PubMed2006

Self-reported benefits from successive bilateral cochlear implantation in post-lingually deafened adults: randomised controlled trial.

Adult users of unilateral Nucleus CI24 cochlear implants with the SPEAK processing strategy were randomised either to receive a second identical implant in the contralateral ear immediately, or to wait 12 months while they acted as controls for late-emerging benefits of the first implant. Twenty four subjects, twelve from each group, completed the study. Receipt of a second implant led to improvements in self-reported abilities in spatial hearing, quality of hearing, and hearing for speech, but to generally non-significant changes in measures of quality of life. Multivariate analyses showed that positive changes in quality of life were associated with improvements in hearing, but were offset by negative changes associated with worsening tinnitus. Even in a best-case scenario, in which no worsening of tinnitus was assumed to occur, the gain in quality of life was too small to achieve an acceptable cost-effectiveness ratio. The most promising strategies for improving the cost-effectiveness of bilateral implantation are to increase effectiveness through enhanced signal processing in binaural processors, and to reduce the cost of implant hardware.

Adult↗
PubMed2005

Management of the patient and family with neurofibromatosis 2: a consensus conference statement.

A consensus conference on neurofibromatosis 2 (NF2) was held in 2002 at the request of the United Kingdom (UK) Neurofibromatosis Association, with particular emphasis on vestibular schwannoma (VS) surgery. NF2 patients should be managed at specialty treatment centres, whose staff has extensive experience with the disease. All NF2 patients and their families should have access to genetic testing because presymptomatic diagnosis improves the clinical management of the disease. Some clinical manifestations of NF2, such as ocular abnormalities, can be detected in infancy; therefore, clinical screening for at-risk members of NF2 families can start at birth, with the first magnetic resonance (MRI) scan at 10-12 years of age. Minimal interference, maintenance of quality of life, and conservation of function or auditory rehabilitation are the cornerstones of NF2 management, and the decision points to achieve these goals for patients with different clinical presentations are discussed.

Adult↗
PubMed1999

Phenobarbital responsiveness conferred by the 5'-flanking region of the rat CYP2B2 gene in transgenic mice.

Phenobarbital (PB) is a prototype for a class of agents that produce marked transcriptional activation of a number of genes, including certain cytochrome P-450s. We used transgenic mouse approaches and multiple gene reporters to assess the functional consequences of specific deletions and site-specific mutations within the 2.5kb 5'-flanking region of the rat CYP2B2 gene. Protein-DNA interactions at the PBRU domain also were characterized. Using the transgenic models, we demonstrate that sequences between -2500 and -1700bp of the CYP2B2 gene are critical for PB induction; mice with 1700 or 800bp of 5'-flanking CYP2B2 sequence are not PB responsive. DNA affinity enrichment techniques and immunoblotting and electromobility shift assays were used to determine that nuclear factor 1 (NF-1) interacts strongly with a site centered at -2200bp in the PB responsive unit (PBRU) of CYP2B2. To test the functional contribution of NF-1 in PB activation, we introduced specific mutations within the PBRU NF-1 element and demonstrated that these mutations completely ablate the binding interaction. However, transgenic mice incorporating the mutant NF-1 sequence within an otherwise wild-type -2500/CYP2B2 transgene maintained full PB responsiveness. These results indicate that, despite the avidity of the respective DNA-protein interaction within the PBRU in vitro, NF-1 interaction is not an essential factor directing PB transcriptional activation in vivo.

Animals↗
PubMed1999

Feingold syndrome--a cause of profound deafness.

A case of Feingold syndrome is presented with a previously undescribed association of bilateral profound hearing impairment. Computed tomography (CT) scanning revealed severe narrowing of the internal auditory meatuses at the peripheral end with non-existent auditory nerves. This pathology is significant in the future habilitation of the child, as cochlear implantation is not possible. Children with multiple congenital anomalies should have radiological investigations before hopes are raised with respect to cochlear implantation.

Abnormalities, Multiple↗
PubMed1997

Cochlear implantation in otosclerosis: a unique positioning and programming problem.

A case is reported in which a Nucleus 22 channel cochlear implant was inserted into the basal turn of the cochlea of a patient with advanced otosclerosis. It then passed out of the anterior end of the basal turn into an otospongiotic cavity related to the cochlea. Seven electrodes were located in the basal turn and it was possible to map them sufficiently well for the patient to derive considerable benefit from the implant. The problem of implant induced facial nerve stimulation in otospongiosis is also discussed.

Cochlear Implants↗
PubMed1997

Cochlear implantation after bacterial meningitis: the dangers of delay.

A case is described of a child of 2.6 years who developed total deafness after acute bacterial meningitis. Rapid obliteration of the cochleas due to osteoneogenesis led to limited cochlear implantation. The case is made for fast tracking these children to cochlear implant teams before neoossification becomes established.

Acute Disease↗
PubMed1995

Nucleus 20-channel and 21-channel auditory brain stem implants: first European experiences.

Central electrical stimulation of the auditory pathway can allow hearing in patients suffering from deafness localized in the auditory nerve. Developments in a multichannel auditory brain stem implant based on the Nucleus Mini 22 cochlear implant with transcutaneous signal transmission is discussed. The device has been implanted in seven European patients who suffered from neurofibromatosis type 2. Preliminary speech perception results and patient satisfaction are encouraging, and the data presented include some limited open-set speech recognition.

Auditory Threshold↗
PubMed1994

Hearing loss.

Explore the source record for details and available documents.

Deafness↗
PubMed1993

Phenobarbital induction and tissue-specific expression of the rat CYP2B2 gene in transgenic mice.

To investigate molecular events regulating the transcription of genes inducible by phenobarbital, transgenic mouse strains were developed incorporating rat cytochrome P450 2B2 (CYP2B2) genes. Expression in mouse tissues was analyzed for two series of rat CYP2B2 gene constructs, of 19 and 39 kilobase pairs total length, each containing the entire coding region, introns, and 3'-flanking sequences of CYP2B2, but differing in the respective lengths of 5'-flanking sequence. One group of mice, whose transgene included the complete 2B2 gene but only 800 base pairs of 5'-proximal sequence, were not phenobarbital-inducible in mouse liver or in any extrahepatic tissue; rather, these genes were expressed at very high levels constitutively and selectively in only kidney and liver. A second group of mice with an identical transgene, except for the presence of an additional 19 kilobase pairs of 5'-flanking sequence, expressed 2B2 only in the liver and at high levels only after phenobarbital treatment, analogous to the expression pattern observed for the endogenous CYP2B2 gene in the rat. These results demonstrate that, in vivo, phenobarbital induction and tissue-specific control requires interaction of regulatory elements far upstream of the core CYP2B2 promoter region and upstream of motifs indicated previously as determinants of phenobarbital responsiveness.

Animals↗