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Biomedical subjects

S Henderson

Publications and source records attributed to S Henderson.

At least 109 records · Page 6Linked to original sources
PubMed1994

Platelet bacterial contamination and the use of a chemiluminescence-linked universal bacterial ribosomal RNA gene probe.

BACKGROUND: Currently, the maximum outdate for platelets is 5 days, because of the increasing chance of bacterial growth over time. Various methods for rapid detection of bacterial contamination of blood components have been described, with mixed results and no general acceptance. A recently described, molecular biologic approach for the detection of bacterial contamination involves a chemiluminescence-linked universal DNA bacterial probe to a highly conserved bacterial region of ribosomal RNA (rRNA). STUDY DESIGN AND METHODS: A multicenter trial of a chemiluminescence-linked universal bacterial rRNA probe for the detection of bacterial contamination in platelet concentrates is described. At each of five sites, platelet concentrates (no older than 1 day from date of phlebotomy) were inoculated in triplicate with isolates of four bacterial species (Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus epidermidis, and Staphylococcus aureus) to a final concentration of 10 to 50 colony-forming units (CFUs) per mL and in triplicate to a final concentration of 1000 CFUs per mL. At one site, an additional 6 platelet concentrates were inoculated with sterile saline to serve as controls. Inoculated units were then subjected periodically to quantitative cultures and probe analyses. A total of 126 platelet concentrates were studied over a period of 7 days (120 inoculated with bacteria and 6 with sterile saline). RESULTS: This assay was, in some cases, able to detect S. aureus bacterial contamination in the range of 100 to 1000 CFUs per mL; the majority of samples (B. cereus, P. aeruginosa, S. aureus, and S. epidermidis) with contamination exceeding 10(4) CFUs per mL; and all samples with contamination of 2.1 x 10(5) CFUs per mL or greater. Increasing the sample size from the recommended 0.4 mL to 1.0 mL resulted in an unacceptable loss of specificity (83.3%). CONCLUSION: The routine use of this assay would be expected to result in a decreased risk of septic platelet transfusion reactions and could lead to a lengthening of the current 5 day storage period for platelets. Further, the pooling of random-donor platelet concentrates before storage instead of immediately before transfusion may be possible if this rRNA probe is employed to detect bacteria in the pool.

Bacillus cereus↗
PubMed1994

Low mortality rate in adult respiratory distress syndrome using low-volume, pressure-limited ventilation with permissive hypercapnia: a prospective study.

OBJECTIVES: To evaluate the outcome in patients with severe adult respiratory distress syndrome (ARDS) managed with limitation of peak inspiratory pressure to 30 to 40 cm H2O, low tidal volumes (4 to 7 mL/kg), spontaneous breathing using synchronized intermittent mandatory ventilation from the start of ventilation, and permissive hypercapnia without the use of bicarbonate to buffer acidosis. Also, to compare hospital mortality rate with that predicted by the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system and the "ventilator score." SETTING: A ten-bed general intensive care unit in a university hospital. DESIGN: Prospective, descriptive study. PATIENTS: Fifty-three patients with severe ARDS having a lung injury score of > or = 2.5. INTERVENTIONS: Data recording. RESULTS: The hospital mortality rate was significantly lower than that predicted by the APACHE II scores (26.4% vs. 53.3%, p = .004), even after correcting the latter for the effect of hypercapnic acidosis (26.4% vs. 51.1%, p = .008). The mortality rate increased with increasing number of organ failures, but was only 43% in patients with > or = 4 organ failures, 20.5% with < or = 3 organ failures, and 6.6% with only respiratory failure. The mean maximum PaCO2 was 66.5 torr (range 38 to 158 torr [8.87 kPa, range 5.07 to 21.07]), and the mean arterial pH at the same time was 7.23 (range 6.79 to 7.45). There was no correlation between the maximum PaCO2 or the corresponding pH and the total respiratory rate at the same time. No pneumothoraces developed during mechanical ventilation. CONCLUSIONS: These results lend further support to the hypothesis that limitation of peak inspiratory pressure and reduction of regional lung overdistention by the use of low tidal volumes with permissive hypercapnia may reduce ventilator-induced lung injury and improve outcome in severe ARDS. This hypothesis is supported by a large body of experimental evidence, which also suggests that ventilator-induced lung injury may result in the release of inflammatory mediators, and thus may have the potential to augment the development of multiple organ dysfunction. However, the hypothesis requires testing in a randomized trial as acute hypercapnia could potentially have some adverse as well as beneficial effects.

APACHE↗
PubMed1993

Epstein-Barr virus-coded BHRF1 protein, a viral homologue of Bcl-2, protects human B cells from programmed cell death.

Epstein-Barr virus, a human herpesvirus that persists within the B-lymphoid system, can enhance the survival potential of latently infected B cells in vitro through up-regulation of the cellular survival protein Bcl-2. The possibility that an analogous effect is operative in lytically infected cells was suggested by the observation of distant sequence homology between an Epstein-Barr virus-coded early lytic cycle protein, BHRF1, and Bcl-2. Here we show by gene transfer that BHRF1 resembles Bcl-2 both in its subcellular localization and in its capacity to enhance B-cell survival. Thus confocal microscopic analysis of cells acutely cotransfected with BHRF1 and Bcl-2 expression vectors revealed substantial colocalization of the two proteins in the cytoplasm. In subsequent experiments, stable BHRF1 gene transfectants of Burkitt lymphoma cells paralleled Bcl-2 transfectants in their enhanced survival under conditions that induce cell death by apoptosis. Despite their limited sequence conservation, therefore, the two proteins appear to be functionally homologous. We suggest that BHRF1 provides an alternative, Bcl-2-independent, means of enhancing B-cell survival that may operate during the virus lytic cycle.

Animals↗
PubMed1993

The disabled elderly living in the community: care received from family and formal services.

OBJECTIVES: Based on a community sample, to assess the reasons disabled elderly people need care, the type of formal services they receive, the characteristics of their carers and the degree of psychological morbidity in these carers. DESIGN AND SETTING: A community survey of people aged 70 or more years living in Canberra or Queanbeyan. Survey participants were asked to nominate informants, who were interviewed about the subjects' state of health. The informants provided information on need for care, services received and the role of carers. Informants also reported on their own health, including symptoms of anxiety and depression. RESULTS: Elderly people needed care because of physical disability more often than behavioural disability. Those with physical disability received more formal services and more help from health professionals than those with behavioural disability. Contact with general practitioners was high for both disabled and non-disabled subjects. Carers of the physically disabled had raised levels of anxiety and symptoms of depression, and poorer self-rated health, but carers of the behaviourally disabled did not. Wives, daughters and husbands made up the biggest categories of carers and around two-thirds of carers were women. CONCLUSION: Family carers play an important role in maintaining disabled elderly people in the community and this role is often stressful. Formal services have to be aimed as much at the needs of the carers as at the disabled people themselves.

Activities of Daily Living↗
PubMed1993

Duration of periventricular densities in preterm infants and neurological outcome at 6 years of age.

Parenchymal echogenicities that break down into extensive cystic lesions are generally followed by severe motor deficit. However, the effect of echodensities in the periventricular white matter, so called 'flares', on later development is less well documented. The aim of the present study was to investigate the impact of neonatal flares in preterm infants on neurological status and motor competence at 6 years of age and to see to what extent outcome was related to duration of flares. Forty four children with flares, subdivided into three groups according to the duration of flares, and 62 children with normal scans were assessed on Touwen's neurological examination, the Movement ABC, and the British Ability Scales. No differences in cognitive abilities were found between the groups. The results of the motor assessments showed that performance decreased significantly with increasing duration of flares. In addition, there was a suggestion that this trend was stronger in measures assessing lower limb function than those of upper limb. Teachers were also able to identify differences between the groups of children on the basis of their motor performance in school.

Activities of Daily Living↗
PubMed1993

Physiological and psychological responses to a university fitness session.

The purpose of this study was to examine the physiological and psychological responses to a university fitness session entitled 'popmobility'. A popmobility session consists of 20 min of aerobic activities, 5 min of local muscular endurance exercises and 5 min of flexibility exercises. Ten regular participants of these sessions, women of mean(s.d.) age 21.2(1.5) years, took part in the study. A maximal oxygen uptake (VO2max) treadmill test was performed by each subject to obtain VO2max and maximum heart rate values. In a laboratory, heart rate and VO2 were measured throughout a popmobility session for each subject. Rate of perceived exertion (RPE) was measured every 5 min throughout the session. The mean intensity of the aerobic part of the session ranged from 67.7-82.6% of the subject's VO2max (mean of 76.4% VO2max). The mean heart rate reserve for the aerobic section was 75.6%. While the relative oxygen consumption remained fairly static during the aerobic section, the RPE score rose. The mean(s.d.) total energy expenditure was 236.6(28.4) kcal (range 203-288). The popmobility session is of adequate intensity to improve the aerobic fitness of its participants. Heart rate, as used as a measure of intensity during a popmobility session, would appear to be a fairly accurate indicator of intensity. However, the use of RPE for exercise prescription in popmobility sessions is inappropriate. Popmobility could also be useful in a weight-reduction programme.

Adult↗