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Biomedical subjects

G J Carroll

Publications and source records attributed to G J Carroll.

At least 37 records · Page 2Linked to original sources
PubMed1993

A multistage system to detect epileptiform activity in the EEG.

A PC-based system has been developed to automatically detect epileptiform activity in sixteen-channel bipolar EEG's. The system consists of three stages: data collection, feature extraction, and event detection. The feature extractor employs a mimetic approach to detect candidate epileptiform transients on individual channels, while an expert system is used to detect focal and nonfocal multichannel epileptiform events. Considerable use of spatial and temporal contextual information present in the EEG aids both in the detection of epileptiform events and in the rejection of artifacts and background activity as events. Classification of events as definite or probable overcomes, to some extent, the problem of maintaining high detection rates while eliminating false detections. So far, the system has only been evaluated on development data but, although this does not provide a true measure of performance, the results are nevertheless impressive. Data from 11 patients, totaling 180 minutes of sixteen-channel bipolar EEG's, have been analyzed. A total of 45-71% (average 58%) of epileptiform events reported by the human expert in any EEG were detected as definite with no false detections (i.e., 100% selectivity) and 60-100% (average 80%) as either definite or probable but at the expense of up to nine false detections per hour. Importantly, the highest detection rates were achieved on EEG's containing little epileptiform activity and no false detections were made on normal EEG's.

Adolescent↗
PubMed1993

Phantom sensation.

Explore the source record for details and available documents.

Anesthesia, Spinal↗
PubMed1992

Reduction of the concentration and total amount of keratan sulphate in synovial fluid from patients with osteoarthritis during treatment with piroxicam.

To study the effects of piroxicam on cartilage metabolism in vivo, a three phase (placebo/piroxicam 20 mg/day by mouth/placebo) double blind controlled trial was conducted in patients with osteoarthritis of the knee joint. Twenty one patients were recruited, 19 of whom (11 women, eight men, median age 70 years) completed the treatment schedule. The knee joint under study was aspirated to dryness at four week intervals. Treatment with piroxicam was accompanied by a decrease in the pain score, an improvement in the functional index, and an increased range of movement. Reductions in the concentration (mean (SEM) 120 (6) to 110 (8) micrograms/ml) and the total amount (1.22 (0.34) to 0.99 (0.37) mg) of keratan sulphate, but not the effusion volume (9.4 (2.5) to 8.3 (2.6) ml) were observed during treatment with piroxicam. These findings are consistent with decreased proteoglycan catabolism during treatment with piroxicam. Neither depressed synthesis nor enhanced clearance of degraded proteoglycan fragments can be excluded, however.

Adolescent↗
PubMed1991

Hydroxyapatite crystals are a frequent finding in osteoarthritic synovial fluid, but are not related to increased concentrations of keratan sulfate or interleukin 1 beta.

Synovial fluid (SF) was obtained from 40 patients with varying grades of osteoarthritis (OA) of the knee and examined by transmission electron microscopy to ascertain how frequently hydroxyapatite crystals (HA) were present and whether they were related to disease severity or putative markers or promoters of cartilage resorption. HA crystals were conspicuous and abundant in specimens from 21 of the 40 patients studied. Patients in whom HA was present had significantly larger effusions (13.0 +/- 8.9 vs 8.7 +/- 6.1 ml, p less than 0.05). They also tended to have radiologically more severe disease (radiological grade: 2.91 +/- 0.92 vs 2.39 +/- 0.85, p = 0.056). No difference in keratan sulfate (KS) concentrations was observed. Moreover, despite the presence in some specimens of numerous free histiocytes which were actively phagocytosing HA aggregates, the concentrations of interleukin 1 beta (IL-1 beta), a monocyte product with cartilage and bone resorbing activity, were below the limit of detection (20 pg/ml). Our results confirm that HA crystals are a common finding in patients with OA of the knee and show that HA is associated with larger effusions, but not increased SF concentrations of cartilage proteoglycan substituents (KS) or IL-1 beta.

Aged↗
PubMed1990

Eaton-Lambert myasthenic syndrome: two cases with typical and atypical features.

Eaton-Lambert myasthenic syndrome is a rare disorder of neuromuscular transmission. We are unaware of previous New Zealand reports and present two patients. Characteristic abnormalities in compound muscle action potential amplitude following repetitive nerve stimulation and on single fibre electromyography were present. Both patients also showed mild patchy abnormalities in peripheral nerve conduction. The clinical picture resembled Guillain-Barre syndrome in one patient who developed severe generalised weakness and respiratory failure. In both patients the neurological presentation lead to the recognition of a previously asymptomatic small cell lung carcinoma.

Aged↗
PubMed1989

Sulphasalazine versus penicillamine in the treatment of rheumatoid arthritis.

Fifty-four patients with rheumatoid arthritis were randomized to either sulphasalazine or D-penicillamine in order to compare the short- and long-term efficacy of these two agents in the treatment of rheumatoid arthritis. Decisive improvement was observed in both treatment groups over a 1 year period. Side effects were common in both groups and accounted for termination of therapy in 11 patients during the first year. Radiological deterioration was evident in both treatment groups. A trend toward greater radiological deterioration was observed in patients receiving sulphasalazine, but this was not statistically significant. Only 11 of the 38 patients who completed 1 year of therapy were continuing to take the same drug 5 years later. Eight patients were continuing D-penicillamine and three were still taking sulphasalazine. Among the patients who completed 1 year of therapy, treatment was subsequently terminated because of loss of effective disease control in a significantly higher proportion of patients receiving sulphasalazine (P less than 0.01). The radiological data and the latter observations suggest that D-penicillamine may be a more effective agent for long-term treatment.

Acetyltransferases↗
PubMed1989

Expert system approach to detection of epileptiform activity in the EEG.

An expert system for the automated detection of spikes and sharp waves in the EEG has been developed. The system consists of two distinct stages. The first is a feature extractor, written in the conventional procedural language Fortran, which uses parts of previously published spike-detection algorithms to produce a list of all spike-like occurrences in the EEG. The second stage, written in the production system language OPS5, reads the list and uses rules incorporating knowledge elicited from an electroencephalographer (EEGer) to confirm or exclude each of the possible spikes. Information such as the time of occurrence, polarity and channel relationship are used in this process. A summary of the detected epileptiform events is produced which is available to the EEGer in interpreting the EEG. The performance of the expert system is compared with an EEGer using a 320s segment from an EEG containing epileptiform activity. The system detected 19 events and missed seven (false negative) which the EEGer considered epileptiform. There were no false positive detections.

Biomedical Engineering↗
PubMed1987

Comparison of median and radial nerve sensory latencies in the electrophysiological diagnosis of carpal tunnel syndrome.

An electrophysiological diagnosis of carpal tunnel syndrome (CTS) was made on the basis of the median sensory nerve action potential (SNAP) alone in 79 of 161 (49.1%) symptomatic hands without electrophysiological evidence of a generalised peripheral neuropathy. Comparison of distal sensory latencies (DSLs) for the median and radial nerves yielded abnormal results in 17 of the remaining hands with normal median nerve DSLs, increasing the electrodiagnostic yield to 59.6%. Carpal tunnel decompression has been performed in seven of these hands, with abnormal intraoperative findings reported in two, while all improved clinically following surgery, substantiating the diagnosis of CTS. Although the technique described here would not appear to increase the electrodiagnostic yield more than comparison of DSLs for the median and ulnar nerves, which has been reported previously, it remains an effective, quick and simple procedure for increasing the sensitivity of the nerve conduction studies.

Adolescent↗
PubMed1987

Spectrophotometric measurement of proteoglycans in osteoarthritic synovial fluid.

Cartilage glycosaminoglycans (GAGs) were measured by a spectrophotometric assay in synovial fluid obtained from 30 normal bovine hock joints and 15 osteoarthritic human knee joints. Results were compared with those obtained by radioimmunoassay (RIA). The spectrophotometric method (dimethylmethylene blue (DMB) assay) was found to be simple, safe, and sufficiently reproducible to be of potential value for serial measurement of sulphated GAGs in arthritic joint fluids. The nature of the proteoglycans present in normal bovine and osteoarthritic human synovial fluid was examined by gel chromatography. Whereas normal bovine synovial fluid contained only small molecular weight proteoglycans, osteoarthritic human synovial fluid contained aggregated proteoglycans and predominantly high molecular weight proteoglycan subunits.

Animals↗
PubMed1987

Penicillamine induced polymyositis and dermatomyositis.

Eight Australian cases of D-penicillamine induced polymyositis/dermatomyositis (PM/DM) are reported. In terms of clinical, pathological and electromyographic features, D-penicillamine PM/DM is similar to idiopathic PM/DM but is generally less severe. Recovery is usually rapid when D-penicillamine is withdrawn. Sera were available for study in 6 of the 8 reported cases. Two of the 6 had elevated titers of acetylcholine receptor autoantibodies. Neither of these patients had clinical signs of myasthenia gravis. In 3 of 6 patients typed for C2, no bands were detected suggesting homozygous C2 deficiency. D-penicillamine PM/DM is associated with HLA-B18, B35 and DR4 and is immunogenetically different from idiopathic PM/DM, rheumatoid arthritis and D-penicillamine myasthenia gravis.

Adult↗
PubMed1986

A study of the effects of catabolin on cyclic adenosine monophosphate biosynthesis and prostaglandin E2 secretion in pig articular chondrocytes.

The effects of porcine leucocyte catabolin on prostaglandin E2 (PGE2) secretion and cyclic adenosine monophosphate (cAMP) production were examined in pig articular chondrocytes. Cells were cultured in monolayers on plastic substrates for either 1 or 6 days. Catabolin was found to stimulate PGE2 secretion markedly in all chondrocyte cultures, but had no effect on cAMP biosynthesis, irrespective of the duration of culture, time of exposure or concentration. It is concluded that in pig articular chondrocytes catabolin does not modulate cell function by a cAMP-dependent mechanism.

Animals↗
PubMed1985

Porcine catabolin stimulates prostaglandin E2 secretion but does not affect intracellular cyclic AMP production in pig synovial fibroblasts.

Responses in vitro to partially purified porcine leucocyte catabolin were studied in pig synovial fibroblasts.In serum-free cultures catabolin was found to stimulate secretion of prostaglandin E2 (PGE2) in a time and concentration-dependent manner. The initial stimulation of PGE2 secretion occurred only after a latent interval of six hours. In the same cell line catabolin was found to have no effect on the production of cyclic adenosine monophosphate (cAMP) at times ranging from 30 s to 20 min, even at concentrations up to 15 times greater than that required to promote accelerated release of glycosaminoglycans from cultured bovine nasal cartilage. It is therefore concluded that in pig synovial fibroblasts catabolin evokes a delayed secretion of PGE2 but does not alter cyclic AMP production.

Animals↗
PubMed1983

Treatment of the arthropathy of familial hypercholesterolaemia.

A 29-year-old woman suffering from the arthropathy of familial hypercholesterolaemia was treated with a fat-modified low-cholesterol diet and colestipol. Symptomatic improvement occurred in association with a moderate reduction in the plasma cholesterol concentration. The pathogenesis of the musculoskeletal features of this disease is reviewed, and the implications of this patient's therapeutic response are explored.

Adult↗
PubMed1981

The prevalence of Raynaud's syndrome in rheumatoid arthritis.

To test the validity of the putative association between Raynaud's syndrome and rheumatoid arthritis (RA) 277 patients with rheumatic disorders were questioned about cold-induced colour reactions in the extremities. The time to recover digital temperature after brief immersion in ice water was used to confirm the presence of Raynaud's syndrome. The prevalence of Raynaud's syndrome in the 148 patients with RA and the 59 patients with osteoarthritis was 2.7% and 5.1% respectively. It is concluded that Raynaud's syndrome is not a frequent accompaniment of RA, and it is suggested that in view of the close association between Raynaud's syndrome and certain other disorders, such as mixed connective tissue disease and scleroderma, when patients present with polysynovitis and Raynaud's syndrome special consideration should be given to these conditions.

Arthritis, Rheumatoid↗