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Biomedical subjects

R E Ferner

Publications and source records attributed to R E Ferner.

At least 19 recordsLinked to original sources
PubMed2000

Monitoring of clozapine and norclozapine plasma concentration-time curves in acute overdose.

CASE REPORT: A 40-year-old schizophrenic man was found unconscious, with constricted pupils, sinus tachycardia, and twitching of the limbs. There were signs of lung infection, which was treated with antibiotics, and mild rhabdomyolysis. He regained consciousness over 8 hours, and reported taking 3-4 g clozapine. Recovery was uneventful. Measured peak clozapine and norclozapine concentrations were 3.53 mg/L and 0.70 mg/L, respectively. The concentration-time curves were biphasic, with secondary peaks at approximately 36 hours postadmission. Terminal elimination half-lives were 16.9 hours and 22.5 hours for clozapine and norclozapine, respectively. CONCLUSION: Clozapine and its metabolite norclozapine can show biphasic plasma concentration-time curves after overdosage.

Acute Disease↗
PubMed2000

Evaluation of (18)fluorodeoxyglucose positron emission tomography ((18)FDG PET) in the detection of malignant peripheral nerve sheath tumours arising from within plexiform neurofibromas in neurofibromatosis 1.

OBJECTIVES: The ability of (18)fluorodeoxyglucose positron emission tomography ((18)FDG PET) to detect malignant change in plexiform neurofibromas from patients with neurofibromatosis 1 (NF1) was evaluated. METHODS: Eighteen NF1 patients who presented with pain, increase in size, or neurological deficit associated with a plexiform neurofibroma were assessed. Magnetic resonance imaging determined the site and extent of the lesion. Qualitative(18)FDG PET was performed and the standard uptake value (SUV) measured the regional glucose metabolism. Histological confirmation of the diagnosis was obtained in 10 patients. RESULTS: Twenty three plexiform neurofibromas were detected in 18 patients. Seven malignant peripheral nerve sheath tumours, four high grade and three low grade tumours, occurred in five patients. In one patient the clinical and radiological characteristics of the tumour suggested malignancy, but histology was inconclusive. Fifteen benign plexiform neurofibromas were identified in 12 patients and these findings were confirmed histologically in five lesions from four patients. Ten plexiform neurofibromas occurring in eight patients were considered benign on(18)FDG PET and the patients did not undergo surgery. They remained stable or their symptoms improved on clinical follow up (median 9 months). The results of qualitative (18)FDG PET were interpreted as indicating that 13 plexiform neurofibromas were benign and 10 were malignant. No malignant tumours were classified as benign, but two benign tumours were reported as malignant. The SUV was calculated for 20 tumours and was significantly higher in five malignant tumours 5.4 (SD 2.4), than in 15 benign tumours 1.54 (SD 0.7), p=0.002. There was an overlap between benign and malignant tumours in the SUV range 2.7-3.3. CONCLUSIONS: (18)FDG PET is helpful in determining malignant change in plexiform neurofibromas in NF1. Increased separation between benign and malignant lesions could be obtained by calculating the SUV at about 200 minutes after injection of (18)FDG, when the peak activity concentration is obtained in malignant tumours.

Adolescent↗
PubMed2000

Detailed analysis of the oligodendrocyte myelin glycoprotein gene in four patients with neurofibromatosis 1 and primary progressive multiple sclerosis.

Neurofibromatosis 1 (NF1) is a common autosomal disorder with a wide range of neurological manifestations. The case histories of five patients, including two siblings, are reported who have both neurofibromatosis 1 and primary progressive multiple sclerosis (PPMS). A further patient with both NF1 and PPMS has since been identified. More recently, a systematic clinical review of 138 unselected adult patients with NF1 identified one patient with a slowly progressive spastic paraparesis and multiple high signal hyperintensities on T2 weighted MRI. Molecular genetic studies suggest a mechanism by which the clinical association of progressive white matter disease and NF1 might arise. The gene for NF1 is located on chromosome 17q, spans 350 kb of genomic DNA, and contains 60 exons. The gene for oligodendrocyte myelin glycoprotein (OMgp) is embedded within intron 27b of the NF1 gene. OMgp is a membrane glycoprotein that appears in the human CNS at the time of myelination. It can be detected immunohistochemically on CNS myelin and on the surface of cultured oligodendrocytes. Structurally, OMgp has the potential to function as an adhesion molecule and could contribute to the interactions between the plasma membranes of oligodendrocytes and axons required for myelination and/or axon survival. This study considers the specific hypothesis that PPMS in patients with NF1 results from concurrent mutation of the OMgp gene. The OMgp genes of four unrelated patients with NF1 and PPMS were examined using a combination of Southern blot, dosage polymerase chain reaction, and chemical cleavage of mismatch. The entire OMgp coding sequence, all intronic sequence, the intron-exon boundaries, and 1 kb of flanking sequence were screened. The DNA from two patients was found to contain an alteration in the OMgp gene resulting in an amino acid change of glycine to aspartic acid at codon 21. It is concluded that PPMS in patients with NF1 can occur without concurrent mutation of the OMgp gene. The glycine to aspartic acid polymorphic alteration at codon 21 is neither sufficient nor necessary for the development of PPMS.

Adult↗
PubMed1998

Multiple lower limb non-ossifying fibromas in siblings with neurofibromatosis.

Non-ossifying fibromas are common benign lesions of tubular long bones. There is recognized association of these bony lesions with neurofibromatosis type 1 although the presence of non-ossifying fibromas in familial members with the condition has not previously been reported. We report two siblings with neurofibromatosis and radiological evidence of multiple lower limb non-ossifying fibromas. Both patients presented with pain in the knees and a pathological fracture was observed in one case. Patients with multiple non-ossifying fibromas should be examined carefully for other evidence of neurofibromatosis.

Adolescent↗
PubMed1998

Pyrexia, anaemia and acute renal failure secondary to omeprazole.

We present the case of a 77-year-old woman who initially presented with pyrexia of unknown origin, anaemia and mild renal impairment. When her omeprazole was stopped she improved rapidly. When omeprazole was re-started she developed fever and acute renal failure, which again settled quickly on discontinuation of omeprazole. This case demonstrates how drugs can cause severe multisystem disorders that may appear to be infective or inflammatory.

Acute Kidney Injury↗
PubMed1996

Intellectual impairment in neurofibromatosis 1.

Intellectual problems are a recognized feature of neurofibromatosis 1 (NF1) but their aetiology is unknown. We investigated the frequency, nature, severity and cause of intellectual impairment in NF1. We undertook neurological and psychometric assessments on 103 patients with NF1 and 105 controls equated for age, sex and socio-economic status. The mean full scale IQ was significantly lower in the NF1 than the control group, 88.6 (SD 14.6) compared with 101.6 (SD 14.2). However, the degree of intellectual impairment was mild and only 8% of NF1 patients had an IQ < 70. The NF1 patients also had significantly poorer reading skills and impaired short term memory. On a computerized performance test battery of complex tasks, the NF1 group had significantly slower mean reaction times and higher error rates than the controls. Overall the patients displayed impaired attention and were slow to develop and adapt strategies for complex and unfamiliar tasks. A particular profile of intellectual deficit did not emerge. The presence of neurological and/or medical complications was weakly associated with a lower mean full scale IQ in NF1 patients. Socio-demographic factors, age or sex differences and the presence of macrocephaly did not contribute to neurocognitive deficit in NF1.

Adolescent↗