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Biomedical subjects

M Bradford

Publications and source records attributed to M Bradford.

18 recordsLinked to original sources

Modelling faecal indicator concentrations in large rural catchments using land use and topographic data.

AIMS: To characterize and model spatial variations in faecal-indicator organism concentrations in watercourses draining a large rural catchment during the bathing season. METHODS AND RESULTS: Presumptive coliform (PC), presumptive Eschericia coli (PE) and presumptive enterococci (PEnt) concentrations were determined under base- and high-flow conditions at 24 monitoring points in the Rheidol/Ystwyth catchment, Wales. Relationships with land use and topographic variables within their 'subcatchments' were investigated. Geometric mean (GM) concentrations typically increase more than 10-fold at high flow. The proportion of improved pasture within subcatchments explains 81.6, 73.0 and 85.8%, respectively, of the variance in high-flow GM PC, PE and PEnt concentrations. Distributed modelling suggests that organisms derived from more distant parts of subcatchments may be lost through die-off and sedimentation along watercourses at base flow, although not at high flow. Reductions in concentrations are also evident downstream of reservoir impoundments. CONCLUSIONS: Large rural catchments may contribute substantially to faecal indicator loadings in coastal waters. Indicator concentrations can be modelled successfully using land use and topographic data. SIGNIFICANCE AND IMPACT OF THE STUDY: Development of a modelling approach that provides valuable insight into faecal indicator sources and the transport and survival of these organisms within large catchments.

Environmental Monitoring↗

The nature and source of the head injuries sustained by restrained front-seat car occupants in frontal collisions.

The paper examines the types of head injury sustained by restrained front-seat car occupants in frontal collisions. Injuries are classified into soft tissue, diffuse and focal brain injuries and facial bone or skull fractures. Survivors seldom sustain focal injuries although these are common amongst fatalities. The contact sources within the car are described. Intruding structures and high crash severities are typically associated with high rates of the more severe injuries from steering wheel contact, although some are sustained with intrusion below 11 cm. Low-speed impact testing on nondeployed airbag-equipped wheels is suggested. Toughened glass windscreens are overrepresented amongst those sustaining injuries from glazing materials. Test procedures to reduce injuries from pillar contacts should take account of the dynamic effects of an intruding pillar. Contacts with objects outside the car caused higher rates of severe fractures and brain injury; however, the total numbers are greater from interior contacts.

Abbreviated Injury Scale↗

A review of cervical fractures and fracture-dislocations without head impacts sustained by restrained occupants.

Crash injury reduction via lap-shoulder belt use has been well documented. Like any other interior car component, lap-shoulder belts may be related to injury in certain crashes. Relatively unknown is the fact that cervical fractures or fracture-dislocations to restrained front seat occupants occur where no head contact was evidenced by both medical records and car inspection. A review of the available literature on car crash injuries revealed more than 100 such cases. A review of the National Accident Severity Study (NASS) 80-88 file was also conducted, revealing more examples. Case capsule descriptions from the authors' files are also detailed along with examples of such injuries in infants and children in child restraints. However, cervical fractures or fracture dislocations are rare, as evidenced by the relatively few cases identified in the literature, in the author's files, and by an analysis of NASS 80-90 data that revealed a cervical spine injury frequency of only .4% at the AIS-3 level (Huelke, Morris, and Mackay 1992).

Accidents, Traffic↗

A seven-year experience with methicillin-resistant Staphylococcus aureus.

From July 1983 through June 1990, 319 patients with methicillin-resistant Staphylococcus aureus (MRSA) were identified at the University of California, Davis Medical Center. Initially, our goal was eradication of MRSA from the hospital flora. Our approach was: (a) immediate notification of all MRSA isolates by the microbiology laboratory; (b) strict isolation; (c) cohorting; (d) bathing patients with an iodophor; (e) surveillance cultures of patients and staff; (f) treatment of all colonized persons; and (g) strict isolation on readmission. Control of spread was achieved but eradication was not. In 1987 our strategy was modified in order to establish the least restrictive methods to maintain control of the spread of MRSA. After notification by the microbiology laboratory, we now require: (a) contact isolation; (b) surveillance cultures of patients associated with each new case; and (c) contact isolation for all MRSA patients on readmission. Strict isolation and employee culturing are used only during major outbreaks. We have averaged four new cases of MRSA per month over the 7-year period, including four major outbreaks. Since 1987, we have averaged only three new cases per month with one major MRSA outbreak. Annual cost savings of greater than $50,000 have been realized through the policy modifications. We conclude that the use of contact isolation with some modifications has saved time and money and has successfully controlled the spread of MRSA in our university hospital.

Adult↗

What people want to know about health.

Brighton health authority and Brighton borough council are jointly planning a 'Healthy living centre' to provide a focal point for local health promotion activities. Sandra Winn and Martin Bradford report on a survey of community groups which not only provided information for the development of the centre but also gave useful insight into the community's concerns about health and people's needs for health information.

Adolescent↗

Quantitative ultrasonic detection and classification of diffuse liver disease. Comparison with human observer performance.

A multiparameter ultrasonic tissue characterization system has been developed and tested on several types of diffuse liver disease. The four tissue characterization parameters used are based on the first and second order statistics of the B-scan image. Performance of the system was evaluated using receiver operating characteristic (ROC) analysis and was compared with the performance of experienced human observers viewing B-scan images. The machine-based multiparameter system achieved an area under the ROC curve (Az) of 0.88 for detection of chronic hepatitis in more than 100 proven cases of the disease. This was dramatically better than the performance of human observers (Az = .64, P less than .05) and compares favorably to the performance of other accepted diagnostic tests such as head CT and the PAP smear. For detection of Gaucher's disease, the Az for the system was .92, whereas for separating hepatitis from Gaucher's disease Az was .84. Human observers also did well at these tasks (P greater than .8) using organomegaly as their major criterion for diagnosing Gaucher's disease. For primary biliary cirrhosis the system Az was .80, for glycogen storage disease Az was .94. These results suggest that use of multiparameter tissue characterization can significantly increase the usefulness of ultrasound for evaluation of diffuse liver disease.

Gaucher Disease↗

Inhibition of adenosine 3',5'-cyclic monophosphate phosphodiesterase by colchicine: implications for glucagon and corticosteroid secretion.

In the study reported, colchicine, often regarded as a specific inhibitor of microtubular function, was shown to exert a concentration-dependent inhibition of the low Km cyclic AMP phosphodiesterases of the pancreatic islet, adrenal cortex and various other tissues of the rat. The results indicated that colchicine is only slightly less active as an inhibitor of the enzyme than theophylline on a molar basis and kinetic analysis revealed that both inhibitors acted competitively in the case of the liver enzyme. Our results show that the inhibitory effect of colchicine upon cyclic AMP phosphodiesterase is a general property of the alkaloid at concentrations of 5 x 10(-5)M and above in both endocrine and non-endocrine tissues. Thus, results obtained employing colchicine at concentrations significantly greater than those which are known to lead to microtubular disaggregation must be viewed with great caution if incorrect implication of microtubular participation in biological processes is to be avoided. For example, we propose that the previously reported paradoxical stimulatory effects of colchicine on the secretion of glucagon from the rat pancreatic islet and on steroidogenesis in the rat adrenal may be due to cyclic AMP accumulation consequent upon phosphodiesterase inhibition in these endocrine tissues and not to microtubular disaggregation as has hitherto been assumed.

3',5'-Cyclic-AMP Phosphodiesterases↗

Multilumen catheter sepsis and an educational program to combat it.

Catheter-related sepsis is a problem with many variables. A process of elimination may eventually identify the actual cause(s) of this phenomenon. We began our problem-solving approach by observing personnel inserting and caring for central lines, which showed a lack of compliance with existing protocols. A program was designed to provide the correct procedural activities. This study plans to test whether ongoing educational programs and an infection control department that maintains a high degree of visibility are effective in reducing nosocomial line-related infections.

Catheterization, Central Venous↗