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Biomedical subjects

J Barker

Publications and source records attributed to J Barker.

At least 55 records · Page 3Linked to original sources
PubMed2000

Survival of Salmonella in bathrooms and toilets in domestic homes following salmonellosis.

The survival and environmental spread of Salmonella bacteria from domestic toilets was examined in homes, where a family member had recently suffered an attack of salmonellosis. In four out of six households tested, Salmonella bacteria persisted in the biofilm material found under the recess of the toilet bowl rim which was difficult to remove with household toilet cleaners. In two homes Salmonella bacteria became incorporated into the scaly biofilm adhering to the toilet bowl surface below the water line. Salmonella enteritidis persisted in one toilet for 4 weeks after the diarrhoea had stopped, despite the use of cleaning fluids. Salmonellas were not isolated from normally dry areas such as, the toilet seat, the flush handle and door handle. Toilet seeding experiments were set up with Salmonella enteritidis PT4 to mimic environmental conditions associated with acute diarrhoea. Flushing the toilet resulted in contamination of the toilet seat and the toilet seat lid. In one out of three seedings, Salmonella bacteria were also isolated from an air sample taken immediately after flushing, indicating that airborne spread of the organism could contaminate surfaces in the bathroom. In the seeded toilet Salmonella bacteria were isolated from the biofilm in the toilet bowl below the waterline for up to 50 d after seeding, and also on one occasion from the bowl water. The results suggest that during diarrhoeal illness, there is considerable risk of spread of Salmonella infection to other family members via the environment, including contaminated hands and surfaces in the toilet area.

Adult↗
PubMed2000

Patient Care Bridge--mobile ICU for transit care of the critically ill.

We describe the development and introduction of a Patient Care Bridge--a mobile ICU for the transit care of the critically ill. This stretcher-mounted Patient Care Bridge is being used for intensive transit care of the critically ill in Northland, New Zealand. It carries all the basic intensive care monitoring accoutrements, is lightweight and is suited for pre-hospital, inter-hospital and intra-hospital transit care. It is ideal for patient evacuation from the scene of motor vehicle and sporting accidents, surface transportation of patients by surface ambulance and aeroevacuation of patients by the Helicopter Emergency Medical Service. This economic and space efficient unit has been used for transfer of more than one thousand critically ill patients.

Air Ambulances↗
PubMed1999

Survival of Escherichia coli O157 in a soil protozoan: implications for disease.

Intra-protozoal growth of bacterial pathogens has been associated with increased environmental survival, virulence and resistance to biocides and antibiotics. Using laboratory microcosms we have shown that Escherichia coli O157 survives and replicates in a common environmental protozoan, Acanthamoeba polyphaga. As protozoa are widely distributed in soils and effluents, they may constitute an important environmental reservoir for transmission of E. coli O157 and other pathogens.

Acanthamoeba↗
PubMed1999

Biomedical applications of accelerator mass spectrometry-isotope measurements at the level of the atom.

Accelerator mass spectrometry (AMS) is a nuclear physics technique developed about twenty years ago, that uses the high energy (several MeV) of a tandem Van de Graaff accelerator to measure very small quantities of rare and long-lived isotopes. Elements that are of interest in biomedicine and environmental sciences can be measured, often to parts per quadrillion sensitivity, i.e. zeptomole to attomole levels (10(-21)-10(-18) mole) from milligram samples. This is several orders of magnitude lower than that achievable by conventional decay counting techniques, such as liquid scintillation counting (LSC). AMS was first applied to geochemical, climatological and archaeological areas, such as for radiocarbon dating (Shroud of Turin), but more recently this technology has been used for bioanalytical applications. In this sphere, most work has been conducted using aluminium, calcium and carbon isotopes. The latter is of special interest in drug metabolism studies, where a Phase 1 adsorption, distribution, metabolism and excretion (ADME) study can be conducted using only 10 nanoCurie (37 Bq or ca. 0.9 microSv) amounts or less of 14C-labelled drugs. In the UK, these amounts of radioactivity are below those necessary to request specific regulatory approval from the Department of Health's Administration of Radioactive Substances Advisory Committee (ARSAC), thus saving on valuable development time and resources. In addition, the disposal of these amounts is much less an environmental issue than that associated with microCurie quantities, which are currently used. Also, AMS should bring an opportunity to conduct "first into man" studies without the need for widespread use of animals. Centre for Biomedical Accelerator Mass Spectrometry (CBAMS) Ltd. is the first fully commercial company in the world to offer analytical services using AMS. With its high throughput and relatively low costs per sample analysis, AMS should be of great benefit to the pharmaceutical and biotechnology industries as well as other life science areas.

Biotechnology↗
PubMed1999

Unexplored reservoirs of pathogenic bacteria: protozoa and biofilms.

In the natural, industrial, hospital and domestic environments, there are numerous phenotypes of pathogenic microorganisms, which vary considerably in chemical, physical and biological properties. A link exists between survival, resistance and virulence. In particular, surface-adherent biofilms and bacteria living within protozoa pose potential health problems that are unrecognized by conventional laboratory culture methods.

Animals↗
PubMed1999

Efficient literature searching in diffuse topics: lessons from a systematic review of research on communicating risk to patients in primary care.

Using the example of communication about risk in a primary care setting, this paper puts forward a method of developing and evaluating a detailed search strategy for locating the literature for a systematic review of a 'diffuse' subject. The aim of this paper is to show how to develop a search strategy that maximizes both recall and precision while keeping search outputs manageable. Six different databases were used, namely Medline, Embase, PsychLIT, CancerLIT, Cinahl and Social Science Citation Index (SSCI). The searches were augmented by hand-searching, contacting authors, citation searching and reference lists from included papers. Other databases were searched but yielded no extra references for this subject matter. Of the 99 papers included, 80 were indexed on Medline. The Medline search strategy identified 54 of them and the remaining 26 were located on other databases. The 19 further unique references were found using the other databases and methods of retrieval. A combination of several databases must be used to maximize recall and to increase the precision of searches on individual databases, thus improving the overall efficiency of the search.

Databases, Bibliographic↗
PubMed1999

Specialist nurse counsellor interventions at the time of diagnosis of breast cancer: comparing 'advocacy' with a conventional approach.

Over recent years, specialist breast care nurses have become increasingly recognized as core members of any breast care team within the UK. Part of the role is to support patients at the highly stressful stage of receiving a diagnosis. This paper describes an 'advocacy' style of nurse counsellor intervention which aims to improve patients' preparation for, and involvement in, the diagnostic consultation and provides a framework for future counselling support. One hundred and three women undergoing surgery following diagnosis of breast cancer or a benign breast lump were supported using either this advocacy intervention or a more conventional model of care. The aim was to identify the most effective and appropriate method of intervening at this important stage. Assessment took place before surgery, with 2-week and 6-month follow-ups, and included the Hospital Anxiety and Depression Scale, Rotterdam Symptom Check List and semi-structured interviews addressing perceived quality of care, involvement in decision-making and psycho-social functioning. Whilst the results of many measures were similar for women in the two intervention groups, qualitative data support the implementation of the advocacy method by the breast care nurse.

Adaptation, Psychological↗
PubMed1999

Academic health centers in turbulent times: strategies for survival.

Given the increasingly turbulent health care environment, the strategic adaptation of academic health centers (AHCs) provides an opportunity to investigate the effects of drastic change on a population of organizations. This article identifies and categorizes the adaptive behavior using existing strategic typologies, while exploring the implications for hospital managers.

Academic Medical Centers↗
PubMed1999

Doppler shift anisotropy in small angle neutron scattering.

The two-dimensional patterns in our small angle neutron scattering (SANS) experiments from rapidly moving aerosols are anisotropic. To test the kinematic theory of two-body scattering that describes the anisotropy, we conducted SANS experiments using a constant source of D2O aerosol with droplets moving at approximately 440 m/s, and varied the neutron velocity from 267 to 800 m/s. The theoretically predicted anisotropy of the laboratory scattering intensities agrees well with the experimental results. Based on an analysis of the scattering intensity in the Guinier region, we also determined the particle velocity. The results are in very good agreement with independent velocity estimates based on supersonic flow measurements.

Journal Article↗
PubMed1999

Clinical and pathologic findings in two new allelic murine models of polycystic kidney disease.

Patients with inherited cystic kidney diseases have progressive cystic dilation of nephrons with concomitant loss of functional renal parenchyma and renal failure. Animal models of inherited cystic kidney disease are useful for study of the pathogenesis and molecular basis of cystic renal diseases. This article describes the clinical and pathologic features in two spontaneously occurring murine models of inherited polycystic kidney disease due to independent allelic mutations on mouse chromosome 8. The mutations, designated kat and kat2J, affect a chromosomal segment homologous to a region of human chromosome 4q35; the altered gene has not yet been identified. An allelism test showed that the mutations are at the same locus. The phenotype, inherited as an autosomal recessive, is more severe in kat2J/kat2J mice. Their kidneys are morphologically normal at birth, but by 3 mo of age, cysts affect all levels of the nephron. Adult males have testicular hypoplasia and they are sterile. A few of the oldest kat2J/kat2J mice have focal portal bile duct proliferation and dilation. kat2J/kat2J mice develop anemia and uremia and die before 1 yr of age. In kat/kat mice, the renal cystic disease progresses more slowly but is morphologically similar to that of kat2J/kat2J mice. The progressive cystic transformation of the kidneys in these allelic murine models resembles that seen in humans with autosomal dominant polycystic kidney disease.

Age Factors↗
PubMed1998

Second response to immunoglobulin in recurrent Guillain-Barré syndrome.

Guillain-Barré, syndrome is the most common paralytic illness among healthy adults. With modern critical care, the mortality has fallen although prolonged hospitalisation and significant morbidity are common. Plasma exchange and intravenous immunoglobulin have only recently been shown to be equally efficacious; the combination of plasma exchange plus intravenous immunoglobulin does not confer additional advantage. Contrary to earlier fears, immunoglobulin use is not associated with an increased relapsed rate. Some patients do benefit from a second course of immunoglobulin in recurrent Guillain-Barré syndrome.

Aged↗
PubMed1998

A tacrolimus-related immunosuppressant with reduced toxicity.

BACKGROUND: Tacrolimus (FK506) has potent immunosuppressive properties reflecting its ability to block the transcription of lymphokine genes in activated T cells through formation of a complex with FK506 binding protein-12, which inhibits the phosphatase activity of calcineurin. The clinical usefulness of tacrolimus is limited, however, by severe adverse effects, including neurotoxicity and nephrotoxicity. Although this toxicity, like immunosuppression, appears mechanistically related to the calcineurin inhibitory action of the drug, a large chemistry effort has been devoted to search for tacrolimus analogs with reduced toxicity but preserved immunosuppressive activity that might have enhanced therapeutic utility. METHODS: Here, we report on the identification of such an analog, which was synthetically derived from ascomycin (ASC), the C21 ethyl analog of tacrolimus, by introducing an indole group at the C32 position. The profile of biological activity of indolyl-ASC was characterized in rodent models of immunosuppression and toxicity. RESULTS: Indolyl-ASC was found to exhibit an immunosuppressive potency equivalent to that of tacrolimus in T-cell activation in vitro and in murine transplant models, even though indolyl-ASC bound about 10 times less to intracellular FK506 binding protein-12 than tacrolimus or ASC. Further evaluation of indolyl-ASC revealed that it is threefold less potent than tacrolimus in inducing hypothermia, a response that may reflect neurotoxicity, and in causing gastrointestinal transit alterations in mice. Moreover, indolyl-ASC was at least twofold less nephrotoxic than tacrolimus upon 3-week oral treatment in rats. CONCLUSIONS: Altogether, these data indicate a modest but definite improvement in the therapeutic index for indolyl-ASC compared with tacrolimus in rodent models.

Animals↗