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Biomedical subjects

C Birks

Publications and source records attributed to C Birks.

6 recordsLinked to original sources
PubMed2001

Hip protectors in aged-care facilities: a randomized trial of use by individual higher-risk residents.

OBJECTIVES: To investigate the effect of use of external hip protectors on occurrence of hip fracture. DESIGN: Randomized controlled trial, with randomization at the individual level. SETTING: residential aged-care facilities in urban areas of New South Wales, Australia. PARTICIPANTS: 174 women, aged 75 years and older, who had had two or more falls or one fall requiring hospital admission in the previous 3 months, and who lived in hostels or nursing homes. Eighty-six subjects were in the intervention group and 88 in the control group. INTERVENTION: Use of external hip protectors and encouragement by nurses to use the protectors. MEASUREMENTS: Follow-up visits at approximately 2 weeks and 2, 10 and 18 months to determine falls and fall injury (including hip fracture); we also measured adherence to hip protector use. RESULTS: The mean age of participants was 85; they lived in 32 different aged-care facilities, two-thirds of which were nursing homes. Intervention and control groups had similar baseline characteristics, with a mean Barthel index of 58 at enrollment and a mean Short Portable Mental Status Questionnaire score of six errors, indicating severe disability and major cognitive impairment. During follow-up, a mean of 4.6 falls per person occurred. There was no difference in mortality, with 28 deaths in each group. Eight hip fractures occurred in the intervention group and seven in the control group (hazard ratio 1.46; 95% confidence interval 0.53-4.51). No hip fractures occurred when hip protectors were being worn as directed. Adherence was about 57% over the duration of the study and hip protectors were worn at the time of 54% of falls in the intervention group. Adherence varied markedly between institutions, but the greatest was about 80%. CONCLUSION: Hip protectors were not effective in reducing the incidence of hip fractures in this study, but because of low statistical power, a reduction in risk of hip fracture of up to 50% may not have been detected. There was limited adherence with their use, resulting in a large number of falls occurring without hip protectors in place. All hip fractures in the intervention group occurred when hip protectors were not being used.

Aged↗
PubMed2000

Role of porcine P-selectin in complement-dependent adhesion of human leukocytes to porcine endothelial cells.

BACKGROUND: Rapid leukocyte adherence to donor organ vasculature is a hallmark of hyperacute xenograft rejection. However, the molecular interactions required for leukocyte binding to vascular endothelium have not been characterized. METHODS AND RESULTS: Binding assays performed between human neutrophils and porcine aortic endothelial cells (PAEC) after exposure to human complement demonstrated that adhesion was mediated by both surface-bound C3b and C5b-9 activity. C5b-9-dependent adhesion was blocked by neuraminidase treatment of the neutrophils, suggesting that this binding was mediated by porcine P-selectin. Porcine P-selectin was isolated from a PAEC cDNA library. The porcine P-selectin primary sequence contained an open reading frame encoding 646 amino acids with 82% identity to human P-selectin. Recombinant soluble porcine P-selectin specifically bound to human neutrophils and HL-60 cells. Transfection of COS cells with the full-length porcine P-selectin cDNA resulted in surface expression of the protein and markedly increased the binding of human neutrophils to these cells. The binding of both soluble and COS-expressed porcine P-selectin to human neutrophils was blocked by pretreatment of the neutrophils with neuraminidase or the addition of EDTA. Finally, treatment of PAEC with human thrombin or normal human serum but not purified human C5a- or C8-deficient human serum resulted in the rapid expression of porcine P-selectin on the cell surface. CONCLUSIONS: This report establishes that porcine P-selectin supports the binding of human neutrophils to PAEC in vitro. Further, these data suggest that sublytic deposition of C5b-9 during hyperacute rejection results in the expression of porcine P-selectin, which may contribute to the rapid adhesion of neutrophils to porcine xenografts.

Amino Acid Sequence↗
PubMed2000

Hip protectors improve falls self-efficacy.

OBJECTIVES: To investigate the effect of use of external hip protectors on subjects' fear of falling and falls self-efficacy (belief in their own ability to avoid falling). DESIGN: Randomized controlled trial. SETTING: Aged-care health services in Sydney, Australia. PARTICIPANTS: 131 women aged 75 years or older, who had two or more falls or one fall requiring hospital admission in the previous year and who live at home. Sixty-one subjects were in the intervention group and 70 in the control group. INTERVENTION: Use of external hip protectors and encouragement to use the protectors by an adherence nurse. MEASUREMENTS: At the time of enrolment into a wider study examining the effect of hip protectors on hip fractures, participants recruited at home completed an assessment of fear of falling and falls efficacy as measured by the Falls Efficacy Scale and the Modified Falls Efficacy Scale. At 4-month follow-up, these scales were readministered by an observer who was not aware of the allocation of the participant to intervention or control groups. RESULTS: Fear of falling and falls self-efficacy, as measured by the Falls Efficacy and Modified Falls Efficacy Scales, were similar at baseline in both groups. Fear of falling was present at follow-up in 43% of subjects using hip protectors and 57% of the control group (chi2 = 2.58, P = 0.11). Hip protector users had greater improvement in falls self-efficacy at follow-up as measured by the Falls Efficacy Scale (t = 2.44, P = 0.016) and the Modified Falls Efficacy Scale (t = 2.08, P = 0.039). CONCLUSION: Hip protectors improve falls self-efficacy. As users of hip protectors feel more confident that they can complete tasks safely, they may become more physically active and require less assistance with activities of daily living.

Accidental Falls↗
PubMed1994

The CD39 lymphoid cell activation antigen. Molecular cloning and structural characterization.

CD39, a 70- to 100-kDa molecule expressed primarily on activated lymphoid cells, was previously shown to mediate B cell homotypic adhesion when ligated with a subset of anti-CD39 mAbs. In the present study, we describe the cloning and molecular characterization of human and murine CD39. The nucleotide sequence of human CD39 includes an open reading frame encoding a putative 510 amino acid protein with six potential N-linked glycosylation sites, 11 Cys residues, and two potential transmembrane regions. Murine CD39 shares 75% amino acid sequence identity with human CD39 but fails to cross-react with anti-human CD39 mAbs. Although there were no significant similarities with other mammalian genes, considerable homology was found between CD39 and a guanosine diphosphatase from yeast. A series of mouse-human hybrid molecules was constructed to determine the general topology of CD39 and the location of a biologically functional epitope. These findings and supporting evidence from an anti-CD39 mAb-selected phage peptide display library indicate a likely model wherein a short intracellular N-terminus is followed by a large extracellular loop containing the epitope recognized by stimulatory anti-CD39 mAbs, and a short intracellular C terminus. The results demonstrate that CD39 is a novel cell surface glycoprotein with unusual structural characteristics.

Adenosine Triphosphatases↗