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R Lye

Publications and source records attributed to R Lye.

9 recordsLinked to original sources
PubMed1999

Probability of bilateral disease in people presenting with a unilateral vestibular schwannoma.

BACKGROUND: Some 4%-5% of those who develop vestibular schwannomas have neurofibromatosis type 2 (NF2). Although about 10% of these patients present initially with a unilateral vestibular schwannoma, the risk for a patient with a truly sporadic vestibular schwannoma developing contralateral disease is unknown. METHODS: A United Kingdom survey of 296 patients with NF2 was reviewed for laterality of vestibular schwannoma at presentation and the presence of other NF2 related features. The time to presentation of bilateral disease was calculated for patients presenting with a unilateral tumour. Mutation analysis of the NF2 gene was carried out on all available cases presenting initially with unilateral disease. RESULTS: Of 240 patients with NF2 with vestibular schwannomas, 45 (18%; 32 sporadic, 13 familial) had either a unilateral tumour or delay in detection between the first and contralateral tumours. Among those tested for NF2 mutations, eight of 27 and nine of 13 were identified among sporadic and familial cases respectively. Sporadic cases showed a high female to male ratio and 19 of 32 have not as yet developed a contralateral tumour (mean 4.1 years after diagnosis of the first). Thirteen of 32 sporadic patients developed a contralateral tumour (mean 6.5 years after the first tumour diagnosis, range 0-22 years) compared with 11 of 13 familial patients (mean delay 5 years, range 0-16 years). Seven of the 45 patients had neither a family history of NF2 nor evidence of related tumours at initial presentation (six before the age of 35 years). CONCLUSION: The risk of patients with sporadic unilateral vestibular schwannomata developing a contralateral tumour in the absence of family history or other features of NF2 is low, but those presenting with other neurogenic tumours in addition to vestibular schwannoma are at high risk of harbouring an NF2 mutation in at least a proportion of their somatic cells.

Adolescent↗
PubMed1998

Differential diagnosis of type 2 neurofibromatosis: molecular discrimination of NF2 and sporadic vestibular schwannomas.

Patients who present with unilateral vestibular schwannomas either at a young age or with additional features of type 2 neurofibromatosis (NF2) are at risk of developing bilateral disease and transmitting a risk of neurogenic tumours to their offspring. We have identified 15 patients from a series of 537 with unilateral vestibular schwannomas who also had one or more of the following: other tumours (10/15), features of NF2 (3/15), or a family history of neurogenic tumours (5/15). No germline NF2 mutations were detected and in 7/9 cases where tumour material was available for analysis a germline mutation in the NF2 gene has been excluded. Although a possibility of gonosomal mosaicism still exists, exclusion tests for the offspring are now possible. We suggest a general strategy, based on analysis of tumour DNA, for distinguishing sporadic and familial cases of tumours caused by two hit mechanisms. Application of this strategy suggests that most instances of unilateral vestibular schwannoma which do not fulfil criteria for NF2 represent chance occurrences.

Adult↗
PubMed1996

Staff stress in head injury rehabilitation.

Recent research has suggested that staff working with head-injured (HI) patients experience higher levels of psychopathology than those working with non-HI patients, mirroring findings obtained with relatives of HI subjects. The present study examined this issue further while controlling for the influence of a range of occupational and extraneous, non-occupational factors which moderate the experience of staff stress. The results indicated that nurses involved in the rehabilitation of HI patients did not differ significantly from those working with non-HI patients on measures of overall stress, job satisfaction or psychopathology. The implications of these findings are discussed, with particular relevance to the potentially important protective effect of staff-patient ratios.

Adult↗
PubMed1993

Type 2 neurofibromatosis: the need for supraregional care?

The results of a U.K. study of 145 cases of type 2 neurofibromatosis has shown generally very poor operative results in terms of hearing and facial nerve preservation. Only 9 out of 118 vestibular schwannoma (acoustic neuroma) operations resulted in any clinically detectable hearing preservation and only 32 left the patient with good or normal (House grade I or II) ipsilateral facial nerve function. Although operation is still the definitive treatment of vestibular schwannoma (acoustic neuroma) and may be a lifesaving procedure, it appears that the evidence in favour of early operation is only valid when carried out in highly specialized centres. The special problems of NF2 cases who may go on to develop multiple spinal and cranial tumours making them wheelchair bound and blind as well as deaf warrants a careful experienced approach. Timing of operations may be critical for the enhancement of useful years of quality life. We therefore propose the setting up of a national NF2 register, with the management of cases at a few supraregional centres.

Adult↗
PubMed1982

Prostacyclin and cerebral vessel relaxation.

The authors have studied the ability of prostacyclin to reverse contractions of human basilar arteries in vitro that were induced by a wide range of substances implicated in the etiology of cerebral arterial spasm. Prostacyclin (10(-10) to 10(-6)M) caused a dose-related reversal of contractions induced by 5-hydroxytryptamine, noradrenaline, angiotensin II, prostaglandin (PG)F2 alpha, and U-46619 (a thromboxane-A2 mimetic). These agents were tested at concentrations or volumes that produced almost maximum or maximum responses and those that produced approximately 50% of the maximum response. Contractions induced by maximum concentrations of angiotensin II and U-46619 were least affected by prostacyclin. In addition, contractions induced by thromboxane-A2 generated from guinea-pig lung were reversed in a dose-dependent fashion by prostacyclin. This ability of prostacyclin to physiologically antagonize contractions of the human basilar artery in vitro induced by high concentrations of various spasmogenic agents suggests that such a potent vasodilator agent or more stable analogue may be of value in the treatment of such disorders as cerebral arterial spasm following subarachnoid hemorrhage.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗