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Roger Harris

Publications and source records attributed to Roger Harris.

7 recordsLinked to original sources
PubMed2005

Survey of the chemical defence potential of diatoms: screening of fifty one species for alpha,beta,gamma,delta-unsaturated aldehydes.

In recent years a negative influence of diatom-derived alpha,beta,gamma,delta-unsaturated aldehydes (PUA) on the reproductive success of copepods and invertebrates has been suggested. Since adverse chemical properties of diatoms would question the traditional view of the marine food web, this defense mechanism has been investigated in detail, but the PUA-release by test organisms has only been determined in a few cases. The observed effects were nevertheless frequently discussed from a general point of view often leading to contradictory conclusions. We have examined the PUA-production of 51 diatom species (71 isolates) in order to provide a basis for the interpretation of laboratory and field results on the influence of diatom food on the reproductive success of their consumers. PUA-production is species and strain dependent. Thirty-six percent of the investigated species (38% of the cultivated isolates) release alpha,beta,gamma,delta-unsaturated aldehydes upon cell disruption in concentrations from 0.01 to 9.8 fmol per cell. Thalassiosira rotula and Thalassiosira pacifica, major spring-bloom forming diatoms isolated from Roscoff (Bretagne, English Channel, France) and Puget Sound (Washington, USA) were among the PUA-producing strains.

Aldehydes↗
PubMed2005

Relative utility of serum troponin and the OESIL score in syncope.

OBJECTIVE: To investigate the utility of both a random troponin T level taken greater than 4 h after a syncopal event and the Osservatorio Epidemiologico sulla Sincope nel Lazio (OESIL) score in predicting outcome post syncope. METHODS: We prospectively enrolled 113 adult patients who presented to our ED after a syncopal event. Each patient had a troponin T level taken at least 4 h after the event. The relevant history of the syncope, background medical history and ECG were collected at presentation. Patients were followed up via telephone after 3-6 months and medical records were also examined. The OESIL risk score was calculated for each patient and the predictive value of both the troponin T and OESIL score were analysed for their utility post syncope. RESULTS: Data were analysed for 100 patients. Twenty percent were believed to have a cardiac cause for their syncope. An elevated troponin T level was found to be highly specific (0.99, 95% confidence interval [CI] 0.96-1.0) for adverse cardiac outcome, but with a very low sensitivity (0.13, 95% CI 0-0.3). The OESIL risk score was found to be predictive of an adverse cardiac outcome (receiver-operating characteristic [ROC] 0.73, 95% CI 0.63-0.84) and return to normal function (ROC 0.74, 95% CI 0.63-0.86). CONCLUSIONS: A normal serum troponin T has a poor negative predictive value for adverse cardiac outcomes following syncope. A simple risk stratification system, such as the OESIL score, can predict those patients most at risk after a syncopal episode.

Adult↗
PubMed2005

The effectiveness, acceptability and costs of a hospital-at-home service compared with acute hospital care: a randomized controlled trial.

OBJECTIVE: To compare the safety, effectiveness, acceptability and costs of a hospital-at-home programme with usual acute hospital inpatient care. METHOD: Patients aged 55 years or over being treated for an acute medical problem were randomized to receive either standard inpatient hospital care or hospital-at-home care. Follow-up was for 90 days after randomization. Health outcome measures included physical and mental function, self-rated recovery, health status as assessed by the SF-36, adverse events and readmissions to hospital. Acceptability was assessed using satisfaction surveys and the Carer Strain Index. Costs comprised hospital care, care in the home, community services, general practitioner services and personal health care expenses. RESULTS: In all, 285 people were randomized with a mean age of 80 years. There were no significant differences in health outcome measures between the two randomized groups. Significantly more patients receiving care at home reported high levels of satisfaction, as did more of their relatives. Relatives of the care-at-home group also reported significantly lower scores on the Carer Strain Index. However, the mean cost per patient was almost twice for patients treated at home (NZ 6524 dollars) as for standard hospital care (NZ 3525 dollars). A sensitivity analysis indicated that, if the service providing care in the home had been operating at full capacity, the mean cost per patient episode would have been similar for both modes of care. CONCLUSIONS: This hospital-at-home programme was found to be more acceptable and as effective and safe as inpatient care. While caring for patients at home was significantly more costly than standard inpatient care, this was largely due to the hospital-at-home programme not operating at full capacity.

Aged↗
PubMed2004

Specialist nurse intervention to reduce unscheduled asthma care in a deprived multiethnic area: the east London randomised controlled trial for high risk asthma (ELECTRA).

OBJECTIVE: To determine whether asthma specialist nurses, using a liaison model of care, reduce unscheduled care in a deprived multiethnic area. DESIGN: Cluster randomised controlled trial. SETTING: 44 general practices in two boroughs in east London. PARTICIPANTS: 324 people aged 4-60 years admitted to or attending hospital or the general practitioner out of hours service with acute asthma; 164 (50%) were South Asian patients, 108 (34%) were white patients, and 52 (16%) were from other, largely African and Afro-Caribbean, ethnicities. INTERVENTION: Patient review in a nurse led clinic and liaison with general practitioners and practice nurses comprising educational outreach, promotion of guidelines for high risk asthma, and ongoing clinical support. Control practices received a visit promoting standard asthma guidelines; control patients were checked for inhaler technique. MAIN OUTCOME MEASURES: Percentage of participants receiving unscheduled care for acute asthma over one year and time to first unscheduled attendance. RESULTS: Primary outcome data were available for 319 of 324 (98%) participants. Intervention delayed time to first attendance with acute asthma (hazard ratio 0.73, 95% confidence interval 0.54 to 1.00; median 194 days for intervention and 126 days for control) and reduced the percentage of participants attending with acute asthma (58% (101/174) v 68% (99/145); odds ratio 0.62, 0.38 to 1.01). In analyses of prespecified subgroups the difference in effect on ethnic groups was not significant, but results were consistent with greater benefit for white patients than for South Asian patients or those from other ethnic groups. CONCLUSION: Asthma specialist nurses using a liaison model of care reduced unscheduled care for asthma in a deprived multiethnic health district. Ethnic groups may not benefit equally from specialist nurse intervention.

Adolescent↗
PubMed2002

Emergency management of acute asthma.

BACKGROUND: Life threatening asthma is not an uncommon emergency and all doctors need to have an ordered approach to managing this problem both in the surgery and the home. OBJECTIVE: To develop a plan for the rapid assessment and management of a patient with asthma. The main focus is on severe life threatening asthma and management is based on the equipment and medication a doctor is likely to have available in the surgery. CONCLUSION: The key to successful treatment of life threatening asthma is a rapid assessment of severity, an early emergency call for an ambulance, oxygen, continuous nebulised beta 2 agonist, corticosteroids and the use of parenteral adrenaline for the patient in extremis.

Administration, Inhalation↗