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Biomedical subjects

R Forsyth

Publications and source records attributed to R Forsyth.

At least 19 recordsLinked to original sources
PubMed2003

Noradrenergic agonists for acute traumatic brain injury.

BACKGROUND: Although there have been considerable gains in understanding the cascade of events that lead to secondary injury after traumatic brain injury (TBI), efforts to translate this understanding into new therapeutic, so-called neuroprotective, approaches have so far proven disappointing. Animal models suggest an alternative strategy: agents enhancing monoaminergic transmission, particularly amphetamines, have been shown to promote motor recovery from focal brain injury and it has been suggested that this might represent a complementary means of therapeutic intervention in the later post-injury phase. OBJECTIVES: To evaluate the evidence that amphetamines improve final outcome after traumatic brain injury. SEARCH STRATEGY: We searched MEDLINE, EMBASE, Science Citation Index, Cochrane Controlled Trials Register and the Cochrane Injuries Group's Specialised Register of Controlled Trials. Researchers and authors of published trials were also contacted. SELECTION CRITERIA: Randomised controlled trials comparing the use of a noradrenergic agonist (together with conventional non-pharmacological rehabilitative therapy) versus conventional non-pharmacological rehabilitative therapy alone. DATA COLLECTION AND ANALYSIS: Two reviewers independently screened records, extracted data and assessed trial quality. MAIN RESULTS: Although there is a limited clinical literature addressing this topic, none of the studies identified fully meets inclusion criteria for this review. REVIEWER'S CONCLUSIONS: At present there is insufficient evidence to support the routine use of methylphenidate or other amphetamines to promote recovery from TBI.

Adrenergic alpha-Agonists↗
PubMed2001

Routine intracranial pressure monitoring in acute coma.

BACKGROUND: Studies in traumatic encephalopathy first led to the insight that the damage seen was not just due to direct consequences of the primary injury. A significant, and potentially preventable, contribution to the overall morbidity arose from secondary hypoxic-ischaemic damage. Brain swelling accompanied by raised intracranial pressure (ICP) resulted in inadequate cerebral perfusion with well-oxygenated blood. Detection of raised ICP could be useful in alerting clinicians to the need to improve cerebral perfusion, with consequent reductions in brain injury. OBJECTIVES: To determine whether routine ICP monitoring in all acute cases of severe coma reduces the risk of all-cause mortality or severe disability at final follow up. SEARCH STRATEGY: We searched MEDLINE, EMBASE, The Injuries Group's specialised register and the reference lists of all relevant articles and review articles. In addition we searched the Index of Scientific and Technical Proceedings using "intracranial pressure" as keyword. SELECTION CRITERIA: All randomised controlled studies of real-time ICP monitoring by invasive or semi-invasive means in acute coma (traumatic or non-traumatic aetiology) versus no ICP monitoring (ie clinical assessment of ICP ) DATA COLLECTION AND ANALYSIS: Primary outcome measures were all-cause mortality and severe disability at the end of the follow up period. MAIN RESULTS: No studies meeting the selection criteria have been identified to date. REVIEWER'S CONCLUSIONS: There are no data from randomised controlled trials that can clarify the role of ICP monitoring in acute coma.

Acute Disease↗
PubMed2001

A practical outcome scale for paediatric head injury.

Traumatic brain injury (TBI) is the commonest cause of acquired disability in childhood. A major obstacle to the evaluation of acute and rehabilitative therapies after TBI is the lack of simple descriptors of outcome. We developed the King's Outcome Scale for Childhood Head Injury (KOSCHI), as a specific paediatric adaptation of the original adult Glasgow Outcome Scale (GOS). The KOSCHI expands the five category GOS to provide increased sensitivity at the milder end of the disability range. The GOS category of "persistent vegetative state" was replaced by "vegetative". "Good recovery" was allocated two categories, in acknowledgement of the long term importance of relatively minor sequelae in a developing child. The scale was quick and easy to use. Inter-rater reliability studies show that even with such an apparently simple scale, some training may be required. The KOSCHI provides a practical scale for paediatric head injury which will enable clinicians to describe rate and extent of recovery, and evaluate the effects of service and research interventions.

Adolescent↗
PubMed2001

Friedreich's ataxia presenting after cardiac transplantation.

A 4 year old boy underwent cardiac transplantation because of cardiomyopathy with ischaemia. Following transplantation he developed neurological signs of Friedreich's ataxia and the diagnosis was confirmed with genetic testing. Cardiomyopathy is a rare presentation of Friedreich's ataxia and to our knowledge this is the first reported transplant operation for the cardiomyopathy associated with this condition.

Age of Onset↗
PubMed2001

Recurrent focal epithelial hyperplasia due to HPV13 in an HIV-positive patient.

There are few reports on focal epithelial hyperplasia (FEH) in association with human immunodeficiency virus (HIV) infection; thus the relationship between them has not been completely clarified yet. We present a case of recurrent FEH in an HIV-positive man (the first described in Belgium), which, according to the PCR-DNA testing, was due to human papilloma virus type 13 (HPV13). To our knowledge, based on the accessible literature, this type of HPV has not been detected in any other documented study of FEH in HIV-positive patients before. Our patient experienced three recurrences of FEH in 1 year. It is therefore suggested that immunodeficiency due to HIV infection is responsible for the HPV-related FEH and the subsequent recurrences. In order to support the consideration of FEH as an oral manifestation of an HIV-related opportunistic infection, every new 'HPV-type' oral lesion in HIV-positive patients must be completely documented.

AIDS-Related Opportunistic Infections↗
PubMed1998

Behavioural factors in accidents at road junctions: the use of a genetic algorithm to extract descriptive rules from police case files.

In-depth studies of behavioural factors in road accidents using conventional methods are often inconclusive and costly. To explore an alternative approach, 200 cross-flow junction road accidents were sampled from the files of Nottinghamshire Constabulary, England, coded for computer analysis using a specially devised 'Traffic Related Action Analysis Language', and then examined using a genetic algorithm (or 'rule-finder' program). For comparison, the same analyses were carried out on 100 descriptions of safe turns, and 100 of hypothetical accident descriptions provided by experienced drivers. A number of findings emerged, distinguishing between accidents turning onto and off major roads; those of younger and older drivers; those that resulted in injury or in damage only; and so on. The study suggests that multiple case-studies based on police case files could be very promising, provided homogeneous samples of accidents are used. Genetic algorithms could play a useful role in preliminary assessment, but an 'information bottleneck' remains to be overcome in capturing enough detail from each case for analysis.

Accidents, Traffic↗
PubMed1996

Solar wind magnetic field bending of Jovian dust trajectories.

From September 1991 to October 1992, the cosmic dust detector on the Ulysses spacecraft recorded 11 short bursts, or streams, of dust. These dust grains emanated from the jovian system, and their trajectories were strongly affected by solar wind magnetic field forces. Analyses of the on-board measurements of these fields, and of stream approach directions, show that stream-associated dust grain masses are of the order of 10(-18) gram and dust grain velocities exceed 200 kilometers per second. These masses and velocities are, respectively, about 10(3) times less massive and 5 to 10 times faster than earlier reported.

Cosmic Dust↗
PubMed1996

A role for astrocytes in glucose delivery to neurons?

The present paper examines the possible role of astrocytes in the delivery of glycogen-derived glucose for neuronal metabolism. Such a process would require astrocytic expression of glucose-6-phosphatase. The degree and significance of brain expression of glucose-6-phosphatase (EC 3.1.3.9) has been a subject of controversy. Published immunohistochemical data are consistent with expression of glucose-6-phosphatase by astrocytes, both in vivo and in vitro. In this paper additional confirmation of the expression of glucose-6-phosphatase mRNA in rat brain is presented. Although cultured astrocytes demonstrate glucose-6-phosphatase activity in vitro under assay conditions, there is very limited in vitro evidence that this activity confers a glucose-export capacity on astrocytes. Under most conditions in vitro, lactate export predominates, however this may relate to aspects of the in vitro phenotype. Data relating to astrocytic glucose and lactate export are considered in the context of hypotheses of trafficking by astrocytes of substrates for neuronal metabolism, hypotheses that imply and require compartmentation of these substances, in contrast with current formulations of glucose transport into and within brain that imply no glucose compartmentation. Microdialysis studies of the properties of the brain extracellular fluid (ECF) glucose pool in the freely moving rat were performed seeking evidence of glucose compartmentation. Results of these studies do imply compartmentalisation of brain glucose, and are consistent with a model envisaging the majority of glucose reaching the neuron via the astrocytic intracellular space and the ECF. In addition, such studies provide evidence that rises in ECF glucose concentration are not the direct result of local recruitment of cerebral blood flow, but suggest the influence of intermediate, astrocyte-based mechanisms. Astrocytic glucose-6-phosphatase may permit astrocytes to modulate the trans-astrocytic flux of glucose to adjacent neurons in response to signals reflecting increased neuronal demand.

Animals↗
PubMed1993

Sequencing using pulsed field and image reconstruction.

The use of pulsed fields in a standard manual sequencing set-up results in the separation of > 2 kb on a single gel, as compared to 300-400 bases with a dc field. However, visual reading of the sequence from a film exposed to a pulsed-field gel is not possible for more than 800-900 bases under the best conditions. The use of image reconstruction and enhancement techniques allows the reading of the M13mp18 sequence to > 1 kb, and individual bands can be identified at > 2 kb.

Bacteriophage M13↗
PubMed1988

Residual volume as a tool in body fat prediction.

Possible methods of estimating residual volume for the prediction of body fat have been compared in young and healthy adults, with particular reference to the potential of a rapid helium equilibration method. In the first experiment, 5 women and 5 men performed nitrogen elimination, oxygen dilution and helium equilibration tests; scores for the helium test were higher than for the other two methods, but lay between the predictions made by Bass in 1964 and by Wilmore in 1969 and the values predicted by the equation of Goldman and Becklake in 1959. However, estimates of body density and body fat, based on residual volumes obtained from the prediction equations, did not differ significantly from those obtained directly by helium equilibration. A second experiment compared the helium and the oxygen techniques in 18 men and 18 women, with similar results. A final experiment compared the simple helium equilibration procedure with vital capacity and anthropometric predictions also suited to large scale determinations of body composition. It is concluded that the rapid helium equilibration procedure provides a fast and convenient procedure for the residual volume component of a body fat estimation. However, further study of the adequacy of equilibration is needed in older subjects and in patients with chronic chest disease.

Adipose Tissue↗
PubMed1982

Respiratory resistance of the oral airway.

Oral resistance to respiratory airflow was measured in 5 healthy adult subjects with nasal airways occluded. Measurements were made by means of a minimally invasive plethysmographic computer-aided technique that avoided interference from a face mask or an artificial oral airway. Oral resistance ws found to be similar to that of the normal nasal airway in subjects at rest. As with nasal resistance, oral resistance decreased with increasing exercise. Four different oral airways that are used in pulmonary function testing reduced oral respiratory airflow resistance from a mean of 1.7 cm H2O/L/s to 0.2, 0.3, 0.3, and 0.5 cm H2O/L/s, respectively.

Adult↗