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Biomedical subjects

G Plant

Publications and source records attributed to G Plant.

At least 37 records · Page 2Linked to original sources
PubMed1999

A stop-codon mutation in the BRI gene associated with familial British dementia.

Familial British dementia (FBD), previously designated familial cerebral amyloid angiopathy-British type, is an autosomal dominant disorder of undetermined origin characterized by progressive dementia, spasticity, and cerebellar ataxia, with onset at around the fifth decade of life. Cerebral amyloid angiopathy, non-neuritic and perivascular plaques and neurofibrillary tangles are the predominant pathological lesions. Here we report the identification of a unique 4K protein subunit named ABri from isolated amyloid fibrils. This highly insoluble peptide is a fragment of a putative type-II single-spanning transmembrane precursor that is encoded by a novel gene, BRI, located on chromosome 13. A single base substitution at the stop codon of this gene generates a longer open reading frame, resulting in a larger, 277-residue precursor. Release of the 34 carboxy-terminal amino acids from the mutated precursor generates the ABri amyloid subunit. The mutation creates a cutting site for the restriction enzyme XbaI, which is useful for detecting asymptomatic carriers. Antibodies against the amyloid or homologous synthetic peptides recognize both parenchymal and vascular lesions in FBD patients. A point mutation at the stop codon of BRI therefore results in the generation of the ABri peptide, which is deposited as amyloid fibrils causing neuronal disfunction and dementia.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Inherited prion disease with an alanine to valine mutation at codon 117 in the prion protein gene.

A large English family with autosomal dominant segregation of presenile dementia, ataxia and other neuropsychiatric features is described. Diagnoses of demyelinating disease, Alzheimer's disease, Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker syndrome have been attributed to particular individuals at different times. An Irish family, likely to be part of the same kindred, is also described, in which diagnoses of multiple sclerosis, dementia, corticobasal degeneration and new variant CJD have been considered in affected individuals. Molecular genetic studies have enabled the classification of this disease at the molecular level as one of the group of inherited prion diseases, with the substitution of valine for alanine at codon 117 of the prion protein gene (PRNP). Only three other kindreds have been described world-wide with this mutation and only limited phenotypic information has been reported. Here we describe the phenotypic spectrum of inherited prion disease (PrPA117V). The diversity of phenotypic expression seen in this kindred emphasizes the logic of molecular classification of the inherited prion diseases rather than classification by specific clinicopathological syndrome. Indeed, inherited prion disease should be excluded by PRNP analysis in any individual presenting with atypical presenile dementia or neuropsychiatric features and ataxia, including suspected cases of new variant CJD.

Adult↗
PubMed1999

Decreased CGRP, but preserved Trk A immunoreactivity in nerve fibres in inflamed human superficial temporal arteries.

The peptidergic sensory innervation of cranial blood vessels may play an important part in vascular head pain. The neuropeptides calcitonin gene-related peptide (CGRP) and substance P in sensory fibres are dependent on nerve growth factor (NGF) produced by the blood vessels, and when released from nerve terminals mediate neurogenic inflammation. NGF is increased in inflamed tissues, and acts via its high affinity receptor trk A on nociceptor fibres to produce hyperalgesia. CGRP and trk A immunoreactive nerve fibres have therefore been studied, for the first time, in inflamed (n=7) and non-inflamed (n=10) temporal arteries biopsied from patients with headache and suspected giant cell arteritis. CGRP immunoreactivity was markedly decreased to absent in adventitial nerve fibres in inflamed regions of vessels, which may reflect secretion from nerve terminals, as CGRP immunoreactivity could still be seen in nerve trunks in periadventitial tissue. Trk A immunoreactive nerve fibres were found in a similar distribution to CGRP containing nerve fibres in non-inflamed vessels, and the trk A immunoreactivity was virtually unchanged in inflamed vessels. The evidence supports a role for NGF related mechanisms in inflammatory vascular head pain. Anti-NGF or anti-trk A agents may represent novel analgesics in this condition.

Adult↗
PubMed1998

Training in the use of a tactile supplement to lipreading: a long-term case study.

OBJECTIVE: The major objective of the study was to evaluate the effectiveness of long-term training for an adult subject fitted with the Tactaid VII vibrotactile aid. A secondary goal of this work was to provide a detailed description of how the KTH Tracking Procedure can be used for training and evaluative purposes. DESIGN: An adult male subject was fitted with a Tactaid VII tactile aid and provided with weekly training sessions in its use over an 18 mo period. The KTH Tracking Procedure was used for training and to record the subject's performance over time. Additional post-training measures included sentence lists and consonants presented in an [aCa] frame. RESULTS: The results obtained showed a 19 to 37% improvement in tracking rate when lipreading was supplemented by the Tactaid VII compared with those obtained via lipreading alone. Attempts to supplement lipreading with auditorily presented voicing cues did not result in improved performance. At the completion of the training program, additional tracking measures were obtained with an unfamiliar female speaker. The results of this testing again showed enhanced performance when the Tactaid VII supplemented lipreading. Post-training testing with sentence materials yielded scores of 29.8% correct for lipreading alone and 39.9% correct for lipreading plus the Tactaid VII. The subject's scores for consonants in [aCa] testing were 47.0% correct for lipreading alone and 60.1% correct for lipreading plus the Tactaid VII. CONCLUSIONS: The study showed that the use of the Tactaid VII resulted in improved lipreading performance for a range of materials and with two different speakers. The results also highlight the value of the KTH Tracking Procedure for testing and training purposes.

Adult↗
PubMed1997

Late results justify resection for multiple hepatic metastases from colorectal cancer.

BACKGROUND: Whilst hepatic resection is accepted for single colorectal metastases, the role of surgery for multiple deposits is less certain. This study reports results of a programme of aggressive resection of hepatic metastases. METHODS: Of 150 hepatic resections for colorectal metastases, 107 patients have completed 1-9 years' follow-up for this actuarial survival analysis. Indications for resection were disease confined to the liver, resectability of all metastases and preservation of sufficient hepatic parenchyma. RESULTS: One patient (1 per cent) died after operation and six (6 per cent) suffered serious complications (two surgical and four medical) but with full recovery. Patients who had a radical resection (n = 89) had 1- and 5-year survival rates of 94 and 37 per cent respectively. A palliative group (n = 18) with disease elsewhere (n = 9) or positive histological margins (n = 9) had corresponding survival rates of 56 and 6 per cent. Univariate analysis of the group who had radical surgery demonstrated that survival depended on size of metastases (less than 7 cm) (P = 0.014), width of clear resection margin (greater than 5 mm) (P = 0.004) and primary site (P = 0.010). Factors not affecting outcome were number of metastases, unilateral versus bilateral disease, synchronous versus metachronous spread, tumour differentiation and Dukes stage. Multivariate analysis demonstrated independent survival advantage for small metastases (less than 7 cm) (P = 0.002) and clear resection margin greater than 5 mm (P = 0.037). CONCLUSION: Hepatic resection in selected patients with single and multiple colorectal hepatic metastases is justified.

Colorectal Neoplasms↗
PubMed1997

Speech teaching for deaf children in the age of bilingual/bicultural programs: the role of tactile aids.

Three studies are summarized which show the potential value of tactile aids for the development of improved speech production skills by profoundly deaf children. The first study examined the use of a tactile display of high frequency speech energy (2-7 kHz). The results obtained showed greatly improved discrimination when the tactile display supplemented hearing aid use. In the second study an 18-year-old profoundly deaf man was provided with speech training using tactile aids to provide modeling and feedback. Recordings made pre- and post-training of the subject's productions of consonants in /aCa/ and simple sentences were played to panels of normal hearing listeners. The results showed large improvements in the post-training tokens. The final study outlines the results of speech training with tactile aids provided to a large group of deaf children.

Adolescent↗
PubMed1996

One hundred and fifty hepatic resections: evolution of technique towards bloodless surgery.

A technique of hepatic resection is described and the results of 150 resections are reviewed. Hepatic transection was performed, under intermittent portal inflow occlusion, using ultrasonic aspiration to skeletonize portal branches and venous tributaries. Control of venous haemorrhage during resection was optimized by argon beam coagulation and lowering central venous pressure to between 0 and 4 cmH2O by extradural blockade and systemic nitroglycerine infusion. One patient with jaundice died in hospital, giving a mortality rate of 0.7 per cent. There were no deaths in patients without jaundice and cirrhosis. Fifteen patients (10.0 per cent) had significant complications, nine medical and six surgical, including three bile leaks (2.0 per cent). Mean blood loss was 814 ml for the whole study but only 434 ml in the last 4 years. During this latter period mean blood transfusion in hospital was 0.5 units and mean postoperative haemoglobin value fell by 0.7 g per 100 ml. Hepatic resection can be performed with the same degree of confidence and similar low morbidity as any other major surgical procedure.

Adolescent↗
PubMed1996

Relationship of aided speech recognition to hearing thresholds and aided speech-peak sensation levels in severely and profoundly hearing-impaired adults.

The relationship of speech recognition to hearing threshold levels and to aided speech-peak sensation levels was examined in a group of severely and profoundly hearing-impaired adults. Closed-set vowel and consonant recognition tests were administered at the subjects' most comfortable levels. Both vowel and consonant recognition scores were relatively predictable from hearing threshold level at 2000 Hz, the correlations being -.84 and -.76, respectively. Recognition of most speech-feature contrasts was also predictable from hearing threshold levels, at one or two frequencies, always including 2000 Hz. The predictability of speech recognition was similar, but no better, from aided speech-peak sensation levels than from hearing threshold levels. Vowel and consonant scores were similar to or better than those reported in previous studies, possibly reflecting subject selection factors and/or extensive testing that was used to optimize hearing aid fittings. For the majority of subjects, altering the low-frequency response of the hearing aid did not significantly affect vowel or consonant recognition scores.

Adult↗
PubMed1994

Neuro-ophthalmological presentation of non-invasive Aspergillus sinus disease in the non-immunocompromised host.

Two cases of non-invasive aspergillosis of the nose and paranasal sinuses are described. The first presented with left proptosis and ophthalmoplegia. Imaging and histology showed a maxillary sinus aspergilloma. The second case presented as a compressive optic neuropathy and histology showed allergic aspergillus sinusitis. The pathological distinction between invasive and non-invasive forms of aspergillus sinusitis is important as in invasive aspergillosis surgical treatment is most effectively combined with systemic antifungal treatment, whereas in aspergilloma of the paranasal sinuses surgical drainage of the sinuses alone is usually sufficient, and in allergic aspergillus sinusitis surgery is best combined with systemic or topical steroids. The distinction between invasive and non-invasive forms is particularly important as both may present with cranial neuropathies.

Adult↗
PubMed1993

Case report: allergic aspergillosis of the sphenoid sinus: pitfall on MRI.

Recent reports indicate that fungal sinusitis is more common than previously thought. Four different histological subtypes of Aspergillus sinusitis are now recognized. Fulminant Aspergillosis is usually seen in immunosuppressed patients, and chronic invasive Aspergillus sinusitis, allergic Aspergillus sinusitis and Aspergilloma are seen in the non-immunocompromised individual. We present a case of progressive unilateral visual loss in a 30-year-old woman. The unusual magnetic resonance findings and the value of computed tomography are discussed.

Adult↗
PubMed1993

The speech of adults with acquired profound hearing losses. I: A perceptual evaluation.

Two audio recordings of ten adventitiously profoundly deaf Australian adults and ten age- and sex-matched controls reading a standard passage were played to a panel of ten normally hearing Swedish listeners. One recording consisted of the full speech signal. The second recording presented only the output from a Laryngograph. The listeners were asked to listen to each speaker and then judge whether he or she was adventitiously deafened or normally hearing. When listening to the full speech signal the listeners were able to identify correctly the speakers' hearing status on 92.5% of presentations. The identification rate fell to 65.6% when the listeners only heard the Laryngograph output. If a rating of adventitious deafness was made when listening to the full speech signal, the listeners were asked to state which aspects of the speaker's speech had led them to make this judgement. Of a total of 166 responses 33 related to overall voice quality, 59 to suprasegmental aspects and 74 to segmental aspects. The results of the study are discussed and compared to the literature.

Adult↗
PubMed1989

Teaching lip-reading: the efficacy of lessons on video.

Studies of the efficacy of filmed and videotaped materials for lip-reading self instruction have provided encouraging results. The recent increase in private ownership of VCRs allows widespread home use of video lessons for improving lip-reading skills. Such an approach is particularly, useful for hearing-impaired adults who have no access to lip-reading classes. To fill this need in Australia a 3-hour video cassette of nine lip-reading lessons was produced. The video lessons were tested over a period of 5 weeks. The study showed a significant improvement in the lip-reading skill of students who studied the video cassette compared to a control group who did not. The extent of improvement did not differ for students who studied the video in a class, at home, or as supplementary teaching material. While the age and sex of the subjects did not influence improvement of lip-reading skills, the study showed greater improvement for the relatively poorer lip-readers. More detailed testing of one group of students showed generalization of lip-reading skills to unfamiliar speakers and materials.

Adult↗