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B Jackson

Publications and source records attributed to B Jackson.

At least 19 recordsLinked to original sources
PubMed2026

Antimicrobial-resistant Staphylococcus aureus isolated from Australian wildlife admitted to a veterinary hospital.

Although antimicrobial resistance (AMR) is a growing One Health concern, little is known about AMR in Staphylococcus aureus from Australian wildlife. This study investigated the occurrence, phenotypic AMR profiles, and genetic characteristics of S. aureus from six representative Australian wildlife species admitted to a wildlife hospital in Western Australia, including the western grey kangaroo (Macropus fuliginosus), quenda (Isoodon fusciventer), pelican (Pelecanus conspicillatus), galah (Eolophus roseicapilla), shingleback skink (Tiliqua rugosa) and long-necked turtle (Chelodina colliei). Staphylococcus aureus was isolated from 11.7% (21/180, 95% CI: 7.4%-17.3%) of the animals on admission. Whole genome sequencing identified 13 multi-locus sequence types (STs) and various virulence factors, including the human-specific immune evasion cluster (IEC). Resistance to at least one antimicrobial class was observed in 63.6% of the isolates. The blaZ, erm(T), aac(6')-aph(2″), and tet(L) AMR genes were detected in 63.6%, 13.6%, 4.5%, and 4.5% of S. aureus, respectively. After 7 days of hospitalisation, S. aureus was isolated from 16.5% (16/97, 95% CI: 9.7%-25.4%) of the animals, including two methicillin-resistant S. aureus (MRSA) isolated from two pelicans. The two MRSA were identified as community-associated MRSA clones (mecA-positive ST1-IV and ST93-IV), suggesting direct or indirect transmission between humans and wildlife during hospitalisation may have occurred. This study highlighted Australian wildlife may be a potential reservoir for genetically diverse antimicrobial-resistant S. aureus. AMR surveillance including wildlife using a One Health approach may be required.

Animals↗
PubMed2006

Angry breathing: A prospective study of hostility and lung function in the Normative Aging Study.

BACKGROUND: Hostility and anger are risk factors for, or co-occur with, many health problems of older adults such as cardiovascular diseases, all-cause mortality, and asthma. Evidence that negative emotions are associated with chronic airways obstruction suggests a possible role for hostility in the maintenance and decline of pulmonary function. This study tests the hypothesis that hostility contributes to a faster rate of decline in lung function in older adults. METHODS: A prospective examination was undertaken of the effect of hostility on change in lung function over time. Data are from the VA Normative Aging Study, an ongoing cohort of older men. Hostility was measured in 1986 in 670 men who also had an average of three pulmonary function examinations obtained over an average of 8.2 years of follow up. Hostility was ascertained using the 50-item MMPI based Cook-Medley Hostility Scale. Pulmonary function was assessed using spirometric tests to obtain measures of forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). RESULTS: Baseline pulmonary function differed between high and medium/low hostility groups (mean (SE) percent predicted FEV(1) 88.9 (18.5) v 95.3 (16.9) and FVC 92.5 (16.5) v 98.9 (15.9), respectively; p < 0.01 for both). This overall association between higher hostility and reduced lung function remained significant after adjusting for smoking and education, although the effect size was attenuated for both FEV1 and FVC. Higher hostility was associated with a more rapid decline in lung function, and this effect was unchanged and remained significant for FEV1)in multivariate models but was attenuated for FVC. Each standard deviation increase in hostility was associated with a loss in FEV1 of approximately 9 ml/year. CONCLUSIONS: This study is one of the first to show prospectively that hostility is associated with poorer pulmonary function and more rapid rates of decline among older men.

Age Factors↗
PubMed2006

Homocysteine in assisted reproduction: does oestradiol influence homocysteine levels?

Steroid hormones including oestradiol have been identified as non-genetic factors that may influence plasma homocysteine. In advanced assisted reproduction, plasma oestradiol levels fluctuate markedly during the treatment cycle starting with normal followed by sub- and then supra-physiological levels. Because of the diverse harmful effects that hyperhomocysteinaemia has been associated with, it is imperative to understand how it may be manipulated during assisted reproduction. A total of 30 women undergoing treatment for infertility were recruited and followed through an advanced assisted reproduction cycle. Blood samples were analysed for oestradiol, homocysteine, vitamin B12, red cell folate and plasma folate during each phase. All patients had normal vitamin B12 and folate levels. Predictably, oestradiol showed marked changes as patients progressed through each treatment phase. However, there were no corresponding significant fluctuations in plasma homocysteine. Oestradiol concentration does not influence plasma homocysteine in women with normal vitamin B12 and folate levels undergoing advanced assisted reproduction.

Adult↗
PubMed2006

Methicillin-resistant Staphylococcus aureus on orthopaedic wards: incidence, spread, mortality, cost and control.

We examined the rates of infection and colonisation by methicillin-resistant Staphylococcus aureus (MRSA) between January 2003 and May 2004 in order to assess the impact of the introduction of an MRSA policy in October 2003, which required all admissions to be screened. Emergency admissions were treated prophylactically and elective beds ring-fenced. A total of 5,594 admissions were cross-referenced with 22,810 microbiology results. The morbidity, mortality and cost of managing MRSA-carrying patients, with a proximal fracture of the femur were compared, in relation to age, gender, American Society of Anaesthesiologists grade and residential status, with a group of matched controls who were MRSA-negative. In 2004, we screened 1795 of 1,796 elective admissions and MRSA was found in 23 (1.3%). We also screened 1,122 of 1,447 trauma admissions and 43 (3.8%) were carrying MRSA. All ten ward transfers were screened and four (40%) were carriers (all p < 0.001). The incidence of MRSA in trauma patients increased by 2.6% per week of inpatient stay (r = 0.97, p < 0.001). MRSA developed in 2.9% of trauma and 0.2% of elective patients during that admission (p < 0.001). The implementation of the MRSA policy reduced the incidence of MRSA infection by 56% in trauma patients (1.57% in 2003 (17 of 1,084) to 0.69% in 2004 (10 of 1,447), p = 0.035). Infection with MRSA in elective patients was reduced by 70% (0.56% in 2003 (7 of 1,257) to 0.17% in 2004 (3 of 1,806), p = 0.06). The cost of preventing one MRSA infection was 3,200 pounds. Although colonisation by MRSA did not affect the mortality rate, infection by MRSA more than doubled it. Patients with proximal fractures of the femur infected with MRSA remained in hospital for 50 extra days, had 19 more days of vancomycin treatment and 26 more days of vacuum-assisted closure therapy than the matched controls. These additional costs equated to 13,972 pounds per patient. From this experience we have been able to describe the epidemiology of MRSA, assess the impact of infection-control measures on MRSA infection rates and determine the morbidity, mortality and economic cost of MRSA carriage on trauma and elective orthopaedic wards.

Adult↗
PubMed2005

Anatomical and functional evidence for progressive age-related decline in parasympathetic control of choroidal blood flow in pigeons.

The choroid receives extensive parasympathetic innervation, which in birds arises largely from the ciliary ganglion (CG). Since age-related changes in parasympathetic regulation of choroidal blood flow (ChBF) could contribute to age-related retinal decline, we used anatomical and functional methods to determine if ChBF control by the CG shows age-related decline in pigeons. The efficacy of the choroidal vasodilatory response to activation of the CG preganglionic input from the medial subdivision of the nucleus of Edinger-Westphal (EWM) was assessed using laser Doppler flowmetry (LDF). The EWM receives bisynaptic retinal input, and electrical stimulation of EWM or light stimulation of the retina in young animals produces dramatic choroidal vasodilation. Transcleral LDF was therefore used to measure both basal ChBF and the increases in ChBF elicited by electrical stimulation of EWM or by retinal illumination in 0.5-18 year old pigeons. Fixed cryostat sections of the eye from 0.5 to 22 year old pigeons were immunolabeled for the 3A10 neurofilament-associated antigen to determine if intrachoroidal nerve fibers arising from CG exhibited age-related loss. We focused on superior choroid, since it is the primary target for CG nerve fibers. There was a marked age-related loss in the ChBF vasodilatory response elicited by either EWM stimulation or retinal illumination, as was also true for basal ChBF. A progressive decrease in choroidal nerve fibers of CG origin, to 17% of youthful abundance by 22 years of age, was also observed. The evoked ChBF increase, and basal ChBF, achieved 50% of their age-related decline between the ages of 3 and 4 years, while half the loss in CG innervation of choroid was later, occurring by 10 years. Age-related loss of choroidal nerve fibers occurs in parallel with but more slowly than the reduction in basal ChBF and the choroidal vasodilation that can be elicited via natural (light) or electrical activation of the central neural input to CG choroidal neurons. The prominent age-related decline in parasympathetic control of ChBF early in the pigeon life span could contribute to the age-related retinal decline observed in pigeons.

Aging↗
PubMed2005

Oscillations of a bose-einstein condensate rotating in a harmonic plus quartic trap.

We study the normal modes of a two-dimensional rotating Bose-Einstein condensate confined in a quadratic plus quartic trap. Hydrodynamic theory and sum rules are used to derive analytical predictions for the collective frequencies in the limit of high angular velocities Omega where the vortex lattice produced by the rotation exhibits an annular structure. We predict a class of excitations with frequency sqrt[6]Omega in the rotating frame, irrespective of the mode multipolarity m, as well as a class of low energy modes with frequency proportional to |m|/Omega. The predictions are in good agreement with results of numerical simulations based on the 2D Gross-Pitaevskii equation. The same analysis is also carried out at even higher angular velocities, where the system enters the giant vortex regime.

Journal Article↗
PubMed2005

Implementing evidence-based guidelines:inpatient management of chronic obstructive pulmonary disease.

BACKGROUND: Evidence-based guidelines exist to guide inpatient management of chronic obstructive pulmonary disease (COPD) exacerbations, but we do not know how well these recommendations are adhered to. AIMS: The aims of this study were: (i) to examine concordance with evidence based guidelines for inpatient management of COPD and (ii)to address deficiencies in compliance with guidelines by feedback of audit results and distribution of an education package. METHODS: Retrospective chart reviews were performed using a data collection tool based on current guidelines. Forty-nine consecutive COPD admissions were audited, and results presented to medical staff. An education package was distributed directly after the presentation. One month later,35 consecutive separations were reviewed. Concordance with recommendations supported by the highest level of evidence was calculated. RESULTS: Data were complete for 84 cases. Concordance rates ranged from 0 to 100%. Apart from initiation of systemic steroids (80-83%)and avoidance of intravenous aminophylline (100%),concordance rates were less than 60%. The only significant improvement post-intervention was for steroid duration (10 vs 29%,95% confidence interval for difference (-36.2, -1.8)). CONCLUSION: Recommendations for steroid initiation and avoidance of aminophylline are well adhered to. Concordance rates for other recommendations were generally less than 60%. Concordance with recommendations for steroid duration was significantly improved by our intervention. The findings suggest that to facilitate evidence-based practice, alternative interventions should be evaluated.

Aged↗
PubMed2004

A comparison of methods for measuring serum and urinary markers of bone metabolism in cats.

Biochemical markers of bone cell activity have recently been shown to be useful for monitoring skeletal health in domestic animals, including dogs and horses. The aim of this study was to evaluate a number of biochemical assays, originally developed for use in humans, for their ability to measure indicators of bone cell activity in serum and urine of normal cats over a range of ages. Bone alkaline phosphatase (BAP), a marker of bone formation, was measured in serum using wheatgerm lectin precipitation (WGL) and by ELISA. The curve derived from serial dilution of feline serum was parallel with the ELISA standard curve, indicating species cross-reactivity, and there was a significant relationship between assays (rs = 0.97, P < 0.001). Deoxypyridinoline (DPD), a marker of bone resorption, was measured in its total form in urine by HPLC and ELISA, and in its free form in serum and urine by ELISA. The dilution curve for free DPD in urine showed parallelism with the assay standard curve; however, the curves for total DPD in urine and serum did not. A significant relationship was established between total urinary DPD (HPLC) with total serum DPD (rs = 0.69, P < 0.001), and with free urinary DPD (rs = 0.95, P < 0.001) concentrations. Carboxy-terminal telopeptide of type I collagen (CTX) concentration, another marker of bone resorption, was measured in serum and urine by ELISA, and there was a significant relationship between assays (rs = 0.82, P < 0.001). CTX could not be measured reliably using an auto-analysis method. A significant relationship was established between total urinary DPD (HPLC) with serum CTX (rs = 0.59, P < 0.05), and urinary CTX (rs = 0.65, P < 0.001) concentrations. BAP (ELISA and WGL), total urinary DPD (HPLC), urinary CTX (ELISA), and serum CTX (ELISA) concentrations were significantly inversely correlated with age (rs = -0.66, -0.88, -0.61, -0.70, and -0.51, P < 0.05 respectively). Cats under two years of age had significantly higher BAP, total urinary DPD (HPLC), and urinary CTX concentrations compared to older cats. In conclusion, this study has shown that a number of commercially available assays provide reliable methods for non-invasively monitoring bone cell activity in cats and has shown that bone turnover decreases within the first two years of life, until complete skeletal maturity is attained. Future studies can now be directed at evaluating the potential clinical application of these methods.

Alanine Transaminase↗
PubMed2003

The renal clearance of free and peptide-bound deoxypyridinoline: response to pamidronate treatment of Paget's disease.

Bisphosphonate treatment of Paget's disease results in a large decrease in urinary peptide-bound pyridinolines but a smaller decrease in urinary free pyridinolines. This discrepancy could be explained by changes in renal handling of pyridinoline forms. We studied eight patients with Paget's disease treated with pamidronate. We collected blood and urine at baseline and at 3 and 14 days after treatment. We measured free and total deoxypyridinoline (DPD) in serum (S) and urine (U) by high-performance liquid chromatography (HPLC). The ratio of free to total DPD at baseline was (mean +/- SE) 13 +/- 1% in serum and 37 +/- 3% in urine; at 3 days, this had increased to 25 +/- 3% in serum and 62 +/- 7% in urine. Peptide-bound (pb) DPD decreased significantly 3 days after treatment: UpbDPD -63 +/- 11%, p < 0.001; SpbDPD -51 +/- 8%, p < 0.01. Free DPD decreased in the urine after 14 days: UfDPD -48 +/- 5%, p < 0.01; there was no significant change in SfDPD. The fractional excretion of pbDPD relative to creatinine was less than one at all time-points; however, the fractional excretion of fDPD was significantly greater than one throughout the study. As a consequence, the proportion of free DPD in the urine increased as bone turnover decreased. This resulted in a smaller decrease in urine free compared with peptide-bound DPD in response to bisphosphonate therapy. Thus, the conversion of peptide-bound to free DPD in the kidney may become more efficient as bone turnover decreases as a consequence of pamidronate treatment.

Aged↗
PubMed2002

Accidental suppression of landau damping of the transverse breathing mode in elongated bose-einstein condensates.

We study transverse radial oscillations of an elongated Bose-Einstein condensate using finite-temperature simulations, in the context of a recent experiment at ENS [F. Chevy, Phys. Rev. Lett. 88, 250402 (2002)]]. The mode observed experimentally corresponds to an in-phase collective oscillation of both the condensate and the thermal cloud. Our simulations are in excellent agreement with experiment, accounting for the very small damping rates observed. In contrast to other condensate modes, interatomic collisions are found to be the dominant damping mechanism in this case.

Journal Article↗
PubMed2002

Trojan particles: large porous carriers of nanoparticles for drug delivery.

We have combined the drug release and delivery potential of nanoparticle (NP) systems with the ease of flow, processing, and aerosolization potential of large porous particle (LPP) systems by spray drying solutions of polymeric and nonpolymeric NPs into extremely thin-walled macroscale structures. These hybrid LPPs exhibit much better flow and aerosolization properties than the NPs; yet, unlike the LPPs, which dissolve in physiological conditions to produce molecular constituents, the hybrid LPPs dissolve to produce NPs, with the drug release and delivery advantages associated with NP delivery systems. Formation of the large porous NP (LPNP) aggregates occurs via a spray-drying process that ensures the drying time of the sprayed droplet is sufficiently shorter than the characteristic time for redistribution of NPs by diffusion within the drying droplet, implying a local Peclet number much greater than unity. Additional control over LPNPs physical characteristics is achieved by adding other components to the spray-dried solutions, including sugars, lipids, polymers, and proteins. The ability to produce LPNPs appears to be largely independent of molecular component type as well as the size or chemical nature of the NPs.

Biocompatible Materials↗
PubMed2002

Quadrupole collective modes in trapped finite-temperature Bose-Einstein condensates.

Finite-temperature simulations are used to study quadrupole excitations of a trapped Bose-Einstein condensate. We focus specifically on the m = 0 mode, where a long-standing theoretical problem is to account for an anomalous variation of the mode frequency with temperature. We explain this behavior in terms of the excitation of two separate modes, corresponding to the coupled motion of the condensate and the thermal cloud. The relative amplitude of the modes depends sensitively on the temperature and on the frequency of the harmonic drive used to excite them. Good agreement with experiment is found for appropriate drive frequencies.

Journal Article↗
PubMed2002

Dynamical instability of a condensate induced by a rotating thermal gas.

We study surface modes of the condensate in the presence of a rotating thermal cloud in an axisymmetric trap. By considering collisions that transfer atoms between the condensate and the noncondensate, we find that m>0 modes, which rotate in the same sense as the thermal cloud, damp less strongly than m<0 modes, where m is the polarity of the excitation. We show that above a critical angular rotation frequency, equivalent to the Landau stability criterion, m>0 modes become dynamically unstable, leading to the possibility of vortex nucleation. We also generalize our stability analysis to treat the case where the stationary state of the condensate already possesses a single vortex.

Journal Article↗
PubMed2001

Finite-temperature simulations of the scissors mode in Bose-Einstein condensed gases.

The dynamics of a trapped Bose-condensed gas at finite temperatures is described by a generalized Gross-Pitaevskii equation for the condensate order parameter and a semiclassical kinetic equation for the thermal cloud, solved using N-body simulations. The two components are coupled by mean fields as well as collisional processes that transfer atoms between the two. We use this scheme to investigate scissors modes in anisotropic traps as a function of temperature. Frequency shifts and damping rates of the condensate mode are extracted, and are found to be in good agreement with recent experiments.

Journal Article↗
PubMed2001

Pain measurement scales: a comparison of the visual analogue and faces rating scales in measuring pressure ulcer pain.

OBJECTIVE: Although different pain scales often have been used interchangeably, it is not known whether interchanging them is appropriate. The purpose of this report was twofold: to better understand the statistical properties of the Faces Rating Scale (FRS) so it can be used appropriately in clinical settings and to describe the mathematical relationship between the Visual Analogue Scale (VAS) and the FRS when they are used to quantify pressure ulcer pain in hospitalized elderly patients. DESIGN: Secondary data analyses were performed as part of a cross-sectional study. SETTING AND SUBJECTS: A quality assurance program was undertaken to evaluate pressure ulcer pain perceived by elderly hospitalized patients. All patients without aphasia participated. INSTRUMENTS: The VAS used was a 0 to 100 mm horizontal line demonstrated to have ratio scale properties with high validity and reproducibility, and the FRS used was 6 faces ordered horizontally from smiling to crying, labeled 0 to 5 beneath each face, respectively. METHODS: Nonlinear least squares regression with a Gauss-Newton iterative procedure was used. RESULTS: Among models with cubic, quadratic, and linear terms, only the quadratic term was significant (P <.05). With use of the equation derived, VAS = 3.33*(FRS)(2), the resulting reliability coefficient was r = 0.92. CONCLUSIONS: The nonlinear relationship indicated high reliability between VAS and FRS for pain assessment in populations with diminished verbal and abstract thinking abilities. For readers who would like to translate results from one scale to another, a quadratic equation is provided.

Adult↗
PubMed2001

Anticoagulant therapy. Will computer use improve outcomes?

BACKGROUND: Anticoagulant therapy has been steadily increasing in clinical practice. With its narrow therapeutic range for efficacy and adverse events, this trend can lead to greater morbidity and mortality, making it an increasingly significant clinical, economic, medicolegal and public health issue. OBJECTIVE: To examine issues and challenges arising from the increasing use of anticoagulants in general practice. DISCUSSION: Adherence and regular monitoring by an effective multidisciplinary health care team is critical to optimise anticoagulant therapy. Clinicians, carers and patients need good information, training and support. Adherence to anticoagulation therapy is influenced by clinician interest, skills and involvement in shared decision making and risk counselling. Computerised decision support, based on relevant and comprehensive guidelines for anticoagulant therapy, can improve the way patients and clinicians manage anticoagulant therapy.

Anticoagulants↗