Search PubMed⌕ Search

Biomedical subjects

M Brady

Publications and source records attributed to M Brady.

At least 19 recordsLinked to original sources
PubMed2006

Staff-led interventions for improving oral hygiene in patients following stroke.

BACKGROUND: For people with limitations due to neurological conditions such as stroke, the routine practice of oral care may become a challenge. Evidence-based supported oral care intervention is essential for this patient group. OBJECTIVES: To compare the effectiveness of staff-led oral care interventions with standard care for ensuring oral hygiene for individuals after a stroke. SEARCH STRATEGY: We searched the trials registers of the Cochrane Stroke Group and Oral Health Group (August 2005), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2006), MEDLINE (1966 to February 2006), CINAHL (1982 to February 2006), Research Findings Electronic Register (February 2006), National Research Register (Issue 1, 2006), ISI Science and Technology Proceedings (August 2005), Dissertation Abstracts and Conference Papers Index (August 2005). We scanned reference lists from relevant papers and contacted authors and researchers in the field. SELECTION CRITERIA: We identified randomised controlled trials that evaluated one or more interventions designed to improve oral hygiene. Trials based on a mixed population were included, provided it was possible to extract the data specific to the individuals post stroke. DATA COLLECTION AND ANALYSIS: Two review authors independently classified identified trials according to the inclusion and exclusion criteria, assessed the trial quality and extracted data. Clarification was sought from study authors when required. MAIN RESULTS: Eight eligible randomised controlled trials were identified but only one provided stroke-specific information. It compared an oral health care education training programme (OHCE) delivered to nursing home care assistants to delayed training intervention in the control group. Comparisons were made at one and six months after the intervention, using the primary outcome measures dental plaque and denture plaque, and three secondary outcomes. The data available for the 67 individuals with a stroke (obtained from the larger cluster randomised controlled trial) showed that denture plaque scores were significantly reduced up to six months (p < 0.00001) after the intervention. Staff knowledge (P = 0.0008) and attitudes (P = 0.0001) towards oral care also improved significantly. AUTHORS' CONCLUSIONS: Based on one study with a small number of stroke survivors, providing oral care training for carers in a nursing home setting improves their knowledge of and attitudes towards the provision of oral care. In turn, residents' dentures were cleaner, though other oral hygiene measures did not change. Further evidence relating to oral care interventions is severely lacking, in particular with reference to care in hospital for those following stroke.

Caregivers↗
PubMed2006

Breast composition measurements using retrospective standard mammogram form (SMF).

The standard mammogram form (SMF) representation of an x-ray mammogram is a standardized, quantitative representation of the breast from which the volume of non-fat tissue and breast density can be easily estimated, both of which are of significant interest in determining breast cancer risk. Previous theoretical analysis of SMF had suggested that a complete and substantial set of calibration data (such as mAs and kVp) would be needed to generate realistic breast composition measures and yet there are many interesting trials that have retrospectively collected images with no calibration data. The main contribution of this paper is to revisit our previous theoretical analysis of SMF with respect to errors in the calibration data and to show how and why that theoretical analysis did not match the results from the practical implementations of SMF. In particular, we show how by estimating breast thickness for every image we are, effectively, compensating for any errors in the calibration data. To illustrate our findings, the current implementation of SMF (version 2.2beta) was run over 4028 digitized film-screen mammograms taken from six sites over the years 1988-2002 with and without using the known calibration data. Results show that the SMF implementation running without any calibration data at all generates results which display a strong relationship with when running with a complete set of calibration data, and, most importantly, to an expert's visual assessment of breast composition using established techniques. SMF shows considerable promise in being of major use in large epidemiological studies related to breast cancer which require the automated analysis of large numbers of films from many years previously where little or no calibration data is available.

Algorithms↗
PubMed2006

Do seizures in patients with refractory epilepsy vary between wakefulness and sleep?

AIM: To determine the effects of sleep and wakefulness on seizures in patients with refractory epilepsy recorded while undergoing video-electroencephalography (EEG) telemetry. METHODS: The video-EEG data of patients who had two or more seizures during video-EEG telemetry (n = 270) were reviewed. Fifty seven patients who had seizures both in wakefulness and sleep were identified. The video and ictal EEG data were reviewed, paying specific attention to type of seizures, duration, semiology, lateralisation and number of seizures. RESULTS: Three hundred and sixty two seizures were recorded; 237 seizures while awake and 125 while sleeping. Secondary generalisation occurred more often in sleep than in wakefulness (p < 0.01). Overall, there was no significant effect of sleep on the duration of seizures or ictal EEG change. Sleep and awake seizures differed in only eight patients. CONCLUSION: Secondary generalisation occurred more often in sleep than in wakefulness, perhaps due to the facilitated spread of seizures during sleep. For the most part, however, seizures recorded during sleep did not differ from those recorded during wakefulness.

Drug Resistance↗
PubMed2006

Audit of the management of genital herpes simplex infection.

We evaluated the management of genital herpes simplex virus (HSV) infection at our clinic. Over six months, 135 patients with primary HSV and 97 patients with recurrent HSV attended. Sixty percent of patients presenting within five days of primary infection were treated with oral acyclovir. Only 53% of patients with primary HSV were given written/verbal information. Follow-up appointments were attended by 78%. Seventy-seven percent of patients with recurrent HSV had at least one viral isolate typed and 72% of patients experiencing episodes exceeding, annually, six were offered suppressive therapy. Our results demonstrate successful management of patients with HSV infections but recommendations are made to reach the standards set by BASSH. Furthermore, we illustrate that improved documentation would go a long way in validating the result.

Acyclovir↗
PubMed2005

Preoperative fasting for preventing perioperative complications in children.

BACKGROUND: Children, like adults, are required to fast before general anaesthesia with the aim of reducing the volume and acidity of their stomach contents. It is thought that fasting reduces the risk of regurgitation and aspiration of gastric contents during surgery. Recent developments have encouraged a shift from the standard 'nil-by-mouth-from-midnight' fasting policy to more relaxed regimens. Practice has been slow to change due to questions relating to the duration of a total fast, the type and amount of intake permitted. OBJECTIVES: To systematically assess the effects of different fasting regimens (duration, type and volume of permitted intake) and the impact on perioperative complications and patient wellbeing (aspiration, regurgitation, related morbidity, thirst, hunger, pain, comfort, behaviour, nausea and vomiting) in children. SEARCH STRATEGY: We searched Cochrane Wounds Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, CINAHL, the National Research Register, relevant conference proceedings and article reference lists and contacted experts. SELECTION CRITERIA: Randomised and quasi randomised controlled trials of preoperative fasting regimens for children were identified. DATA COLLECTION AND ANALYSIS: Data extraction and trial quality assessment was conducted independently by two authors. Trial authors were contacted for additional information including adverse events. MAIN RESULTS: Forty-three randomised controlled comparisons (from 23 trials) involving 2350 children considered to be at normal risk of regurgitation or aspiration during anaesthesia. Only one incidence of aspiration and regurgitation was reported. Children permitted fluids up to 120 minutes preoperatively were not found to experience higher gastric volumes or lower gastric pH values than those who fasted. The children permitted fluids were also less thirsty and hungry, better behaved and more comfortable than those who fasted. Clear fluids preoperatively did not result in a clinically important difference in the children's gastric volume or pH. Evidence relating to the preoperative intake of milk was sparse. The volume of fluid permitted during the preoperative period did not appear to impact on children's intraoperative gastric volume or pH contents. AUTHORS' CONCLUSIONS: There is no evidence that children who are not permitted oral fluids for more than six hours preoperatively benefit in terms of intraoperative gastric volume and pH over children permitted unlimited fluids up to two hours preoperatively. Children permitted fluids have a more comfortable preoperative experience in terms of thirst and hunger. This evidence applies only to children who are considered to be at normal risk of aspiration/regurgitation during anaesthesia.

Adolescent↗
PubMed2003

Preoperative fasting for adults to prevent perioperative complications.

BACKGROUND: Fasting before general anaesthesia aims to reduce the volume and acidity of stomach contents during surgery, thus reducing the risk of regurgitation/aspiration. Recent guidelines have recommended a shift in fasting policy from the standard 'nil by mouth from midnight' approach to more relaxed policies which permit a period of restricted fluid intake up to a few hours before surgery. The evidence underpinning these guidelines however, was scattered across a range of journals, in a variety of languages, used a variety of outcome measures and methodologies to evaluate fasting regimens that differed in duration and the type and volume of intake permitted during a restricted fasting period. Practice has been slow to change. OBJECTIVES: To systematically review the effect of different preoperative fasting regimens (duration, type and volume of permitted intake) on perioperative complications and patient wellbeing (including aspiration, regurgitation and related morbidity, thirst, hunger, pain, nausea, vomiting, anxiety) in different adult populations. SEARCH STRATEGY: Electronic databases, conference proceedings and reference lists from relevant articles were searched for studies of preoperative fasting in August 2003 and experts in the area were consulted. SELECTION CRITERIA: Randomised controlled trials which compared the effect on postoperative complications of different preoperative fasting regimens on adults were included. DATA COLLECTION AND ANALYSIS: Details of the eligible studies were independently extracted by two reviewers and where relevant information was unavailable from the text attempts were made to contact the authors. MAIN RESULTS: Thirty eight randomised controlled comparisons (made within 22 trials) were identified. Most were based on 'healthy' adult participants who were not considered to be at increased risk of regurgitation or aspiration during anaesthesia. Few trials reported the incidence of aspiration/regurgitation or related morbidity but relied on indirect measures of patient safety i.e. intra-operative gastric volume and pH. There was no evidence that the volume or pH of participants' gastric contents differed significantly depending on whether the groups were permitted a shortened preoperative fluid fast or continued a standard fast. Fluids evaluated included water, coffee, fruit juice, clear fluids and other drinks (e.g. isotonic drink, carbohydrate drink). Participants given a drink of water preoperatively were found to have a significantly lower volume of gastric contents than the groups that followed a standard fasting regimen. This difference was modest and clinically insignificant. There was no indication that the volume of fluid permitted during the preoperative period (i.e. low or high) resulted in a difference in outcomes from those participants that followed a standard fast. Few trials specifically investigated the preoperative fasting regimen for patient populations considered to be at increased risk during anaesthesia of regurgitation/aspiration and related morbidity. REVIEWER'S CONCLUSIONS: There was no evidence to suggest a shortened fluid fast results in an increased risk of aspiration, regurgitation or related morbidity compared with the standard 'nil by mouth from midnight' fasting policy. Permitting patients to drink water preoperatively resulted in significantly lower gastric volumes. Clinicians should be encouraged to appraise this evidence for themselves and when necessary adjust any remaining standard fasting policies (nil-by-mouth from midnight) for patients that are not considered 'at-risk' during anaesthesia.

Adult↗
PubMed2003

Correction of uneven illumination (vignetting) in digital microscopy images.

BACKGROUND: Many digital microscopy images suffer from poor illumination at the peripheries (vignetting), often attributable to factors related to the light path between the camera and the microscope. A commonly used method for correcting this has been to use the illumination of an empty field as a correction filter (white shading correction). AIMS: To develop an alternative shading correction method that does not require this additional image. METHODS: / RESULTS: This report outlines an alternative shading correction method that is based upon the intrinsic properties of the image, which are revealed through Gaussian smoothing. The technique can be implemented within Adobe Photoshop or other graphics editing software and works well with both haematoxylin and eosin and immunohistochemical images. CONCLUSIONS: This technique provides an effective means of optimising digital microscopy image appearances for printing, image analysis, or telepathology.

Computer Graphics↗
PubMed2001

Effect of combination therapy including protease inhibitors on mortality among children and adolescents infected with HIV-1.

BACKGROUND: Combination therapy including protease inhibitors has been shown to be effective in treating adults infected with human immunodeficiency virus type 1 (HIV-1), but there are only limited data regarding the treatment of children and adolescents. METHODS: A cohort of 1028 HIV-1-infected children and adolescents, from birth through 20 years of age, who were enrolled in research clinics in the United States before 1996 was followed prospectively through 1999. We used proportional-hazards regression models to estimate the effect on mortality of combination therapy including protease inhibitors. RESULTS: Seven percent of the subjects were receiving combination therapy including protease inhibitors in 1996; by 1999, 73 percent were receiving such therapy. In univariate analyses, a higher base-line percentage of lymphocytes that were CD4-positive, a higher weight for age, a higher height for age, black race, Hispanic ethnic background, younger age, and perinatally acquired infection were associated with a longer median time to the initiation of this type of therapy (P<0.001). After adjustment for covariates, the differences among racial and ethnic groups in the time to initiation were not statistically significant. Mortality declined from 5.3 percent in 1996 to 2.1 percent in 1997, 0.9 percent in 1998, and 0.7 percent in 1999 (P for trend <0.001). There were reductions in mortality in all subgroups defined according to age, sex, percentage of CD4+ lymphocytes, educational level of the parent or guardian, and race or ethnic background. In adjusted analyses, the initiation of combination therapy including protease inhibitors was independently associated with reduced mortality (hazard ratio for death, 0.33; 95 percent confidence interval, 0.19 to 0.58; P<0.001). CONCLUSIONS: The use of combination therapy including protease inhibitors has markedly reduced mortality among children and adolescents infected with HIV-1.

Adolescent↗
PubMed2001

Variable fate of virus-specific CD4(+) T cells during primary HIV-1 infection.

Impairment of CD4(+) T lymphocyte responses to human immunodeficiency virus (HIV)-derived antigens is the classic immunological defect observed during the chronic phase of HIV-1 infection. Early intervention with potent antiretroviral therapy (ART) can preserve HIV-specific CD4(+) T lymphocyte reactivity, providing indirect evidence that such responses are mounted during primary infection and subsequently lost in the majority of infected individuals. Here, we demonstrate early and dramatic expansions of functional HIV-specific CD4(+) T lymphocyte frequencies directly ex vivo. These responses are initially of broad specificity, and can disappear rapidly during the natural course of primary infection. This process of loss is variable, such that the rapidity and extent of functional compromise differs between individuals. Institution of ART during these early phases of HIV-1 infection preserves patterns of functional reactivity within the HIV-specific CD4(+) T lymphocyte population. However, there was no evidence for the restoration of deleted responses. These findings indicate that, in some individuals at least, ART must be administered within a narrow window of opportunity during primary HIV-1 infection to effect substantial immune preservation.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Temporal autocorrelation in univariate linear modeling of FMRI data.

In functional magnetic resonance imaging statistical analysis there are problems with accounting for temporal autocorrelations when assessing change within voxels. Techniques to date have utilized temporal filtering strategies to either shape these autocorrelations or remove them. Shaping, or "coloring," attempts to negate the effects of not accurately knowing the intrinsic autocorrelations by imposing known autocorrelation via temporal filtering. Removing the autocorrelation, or "prewhitening," gives the best linear unbiased estimator, assuming that the autocorrelation is accurately known. For single-event designs, the efficiency of the estimator is considerably higher for prewhitening compared with coloring. However, it has been suggested that sufficiently accurate estimates of the autocorrelation are currently not available to give prewhitening acceptable bias. To overcome this, we consider different ways to estimate the autocorrelation for use in prewhitening. After high-pass filtering is performed, a Tukey taper (set to smooth the spectral density more than would normally be used in spectral density estimation) performs best. Importantly, estimation is further improved by using nonlinear spatial filtering to smooth the estimated autocorrelation, but only within tissue type. Using this approach when prewhitening reduced bias to close to zero at probability levels as low as 1 x 10(-5).

Artifacts↗
PubMed2001

Assessing the acceptability, service delivery requirements, and use-effectiveness of the diaphragm in Colombia, Philippines, and Turkey.

The diaphragm is not available in many countries, despite the recommendations of numerous authors that it has important advantages as a woman-controlled method that offers some protection against sexually transmitted diseases, and one that is safe and free of side effects. An interagency team collaborated to introduce the diaphragm in Colombia, the Philippines, and Turkey, using the same protocol to assess the acceptability, service delivery requirements and use-effectiveness of the method. Eighteen public and private sector service delivery sites were involved and a total of 550 women were enrolled in the study. Provider training aimed to improve the quality of care with which all methods were delivered and included counseling about sexuality and reproductive health risks. The cumulative 12-month pregnancy rate of 10.1 (SE 1.7) per 100 woman-years is on the low end of previous studies of the diaphragm, and the 12-month continuation rate (57.2 [SE 2.4] per 100) compares favorably with that for oral contraceptives and the intrauterine device. Focus group discussions conducted with clients and providers indicated that the method was an important alternative for some women, particularly those who had experienced health problems with other methods or were unable to negotiate condom use with their partners. Provider biases diminished as they observed the strategic niche that the diaphragm filled for their clients. While providing the diaphragm requires training and good client-provider interaction, the requirements are consistent with those called for in the Programme of Action of the International Conference on Population and Development (ICPD, 1994). With proper attention to quality of care, the diaphragm can be successfully offered in resource-poor settings.

Adolescent↗
PubMed2001

Enhancement of contrast regions in suboptimal ultrasound images with application to echocardiography.

In this paper we propose a novel feature-based contrast enhancement approach to enhance the quality of noisy ultrasound (US) images. Our approach uses a phase-based feature detection algorithm, followed by sparse surface interpolation and subsequent nonlinear postprocessing. We first exploited the intensity-invariant property of phase-based acoustic feature detection to select a set of relevant image features in the data. Then, an approximation to the low-frequency components of the sparse set of selected features was obtained using a fast surface interpolation algorithm. Finally, a nonlinear postprocessing step was applied. Results of applying the method to echocardiographic sequences (2-D + T) are presented. The results demonstrate that the method can successfully enhance the intensity of the interesting features in the image. Better balanced contrasted images are obtained, which is important and useful both for manual processing and assessment by a clinician, and for computer analysis of the sequence. An evaluation protocol is proposed in the case of echocardiographic data and quantitative results are presented. We show that the correction is consistent over time and does not introduce any temporal artefacts.

Acoustics↗
PubMed2001

Segmentation of brain MR images through a hidden Markov random field model and the expectation-maximization algorithm.

The finite mixture (FM) model is the most commonly used model for statistical segmentation of brain magnetic resonance (MR) images because of its simple mathematical form and the piecewise constant nature of ideal brain MR images. However, being a histogram-based model, the FM has an intrinsic limitation--no spatial information is taken into account. This causes the FM model to work only on well-defined images with low levels of noise; unfortunately, this is often not the the case due to artifacts such as partial volume effect and bias field distortion. Under these conditions, FM model-based methods produce unreliable results. In this paper, we propose a novel hidden Markov random field (HMRF) model, which is a stochastic process generated by a MRF whose state sequence cannot be observed directly but which can be indirectly estimated through observations. Mathematically, it can be shown that the FM model is a degenerate version of the HMRF model. The advantage of the HMRF model derives from the way in which the spatial information is encoded through the mutual influences of neighboring sites. Although MRF modeling has been employed in MR image segmentation by other researchers, most reported methods are limited to using MRF as a general prior in an FM model-based approach. To fit the HMRF model, an EM algorithm is used. We show that by incorporating both the HMRF model and the EM algorithm into a HMRF-EM framework, an accurate and robust segmentation can be achieved. More importantly, the HMRF-EM framework can easily be combined with other techniques. As an example, we show how the bias field correction algorithm of Guillemaud and Brady (1997) can be incorporated into this framework to achieve a three-dimensional fully automated approach for brain MR image segmentation.

Algorithms↗
PubMed2001

A mammographic dilemma: calcification or haemosiderin as a cause of opacities? Validation of a new digital diagnostic tool.

Core biopsies of an area of microcalcification demonstrated large collections of macrophages containing haemosiderin, with evidence of minimal microcalcification on H&E staining. Algorithms were developed that were capable of differentiating with high accuracy those signs due to calcification, using quantitative measurements such as the apparent volume composition of calcium. Using the linear attenuation coefficients of calcification and assuming an ellipsoid model for the 3-dimensional shape of calcification, we computed the relative calcification volume for each region of interest. The difference in the linear attenuation coefficients of iron and calcification allowed the two to be differentiated on a mammogram based on this measure of relative calcification volume.

Breast↗
PubMed2001

Gesture use following right hemisphere brain damage.

A group of eight right hemisphere brain damaged (RHBD) individuals' use of gesture during discourse was explored at two points post stroke. Three topic structured conversational and three procedural discourse samples were elicited at one and six months post stroke. Gestures were analysed in terms of communicative gesture use and use of physical movements. Results suggest the group's use of gesture altered little over time. Some indication of change in the use of head movements and the use of kinetographic gestures were suggested as aspects of gesture use following RHBD that would benefit from further investigation in relation to a non-brain damaged (NBD) control group.

Aged↗