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Biomedical subjects

W Smith

Publications and source records attributed to W Smith.

At least 73 records · Page 4Linked to original sources
PubMed2000

Peripheral arterial embolization: Doppler ultrasound scan diagnosis.

Use of intraoperative monitoring with transcranial Doppler scanning during carotid endarterectomy has enabled identification of embolus signals in the ultrasound spectrum. Extension of this technique to preoperative screening has enabled identification of actively embolizing lesions and correlation with neurologic deficits. We report embolus signals in the peripheral circulation before operation, which aided diagnosis and decision to operate. The patient had been transferred from another institution after multiple revascularization procedures, including posterior tibial artery thrombectomy. Angiography performed on arrival at our institution confirmed an open bypass graft, although a small indentation was noted at the site of the previous posterior tibial artery thrombectomy. Runoff was intact to the plantar arch where there was attenuation of that vessel and occlusion of most digital branches. Duplex monitoring revealed no embolic signals in the graft or in the posterior tibial artery proximal to the previous arteriotomy. Distal to this site, embolic signals were detected. At the time of operation, a large platelet thrombus was identified at the site of the previous arteriotomy, and platelet thrombus was obtained from the plantar artery. It is concluded that doppler ultrasound scanning enables detection of peripheral embolization and the identification and location of lesions with such embolic activity. Diagnostic accuracy may be improved when there is clinical suspicion of embolization, enabling better patient selection for surgical procedures. This report provides the first clinicopathologic characterization of the emboli detected.

Amputation, Surgical↗
PubMed2000

A case study of co-ordinative decision-making in disaster management.

A persistent problem in the management of response to disasters is the lack of co-ordination between the various agencies involved. This paper reports a case study of inter-agency co-ordination during the response to a railway accident in the UK. The case study examined two potential sources of difficulty for co-ordination: first, poorly shared mental models; and, second, a possible conflict between the requirements of distributed decision-making and the nature of individual decision-making. Interviews were conducted with six individuals from three response agencies. Analysis of reported events suggested that inter-agency co-ordination suffered through a widespread difficulty in constructing a reflexive shared mental model; that is, a shared mental representation of the distributed decision-making process itself, and its participants. This difficulty may be an inherent problem in the flexible development of temporary multi-agency organizations. The analysis focused on a distributed decision over how to transport casualties from an isolated location to hospital. This decision invoked a technique identified here as the progression of multiple options, which contrasts with both recognition-primed and analytical models of individual decision-making. The progression of multiple options appeared to be an effective technique for dealing with uncertainty, but was a further source of difficulty for inter-agency co-ordination.

Communication↗
PubMed2000

Effect of infection control measures on the frequency of upper respiratory infection in child care: a randomized, controlled trial.

BACKGROUND: Acute upper respiratory infections are common in children who attend child care, and preventing transmission of disease in this setting depends on actions by child care staff. We set out to discover whether transmission of respiratory infections in child care could be reduced by improved infection control procedures. METHODS: We performed a cluster, randomized, controlled trial of an infection control intervention conducted in child care centers in 1 city in Australia. The intervention was training of child care staff about transmission of infection, handwashing, and aseptic nosewiping technique. Implementation of the intervention was recorded by an observer. Illness was measured by parent report in telephone interviews every 2 weeks. RESULTS: There were 311 child-years of surveillance for respiratory symptoms. By multivariable analysis, there was no significant reduction in colds in intervention center children across the full age range. However, a significant reduction in respiratory illness was present in children 24 months of age and younger. When compliance with infection control practices was high, colds in these children were reduced by 17%. CONCLUSIONS: This trial supports the role of direct transmission of colds in young children in child care. The ability of infection control techniques to reduce episodes of colds in children in child care was limited to children 24 months of age and under.

Australian Capital Territory↗
PubMed2000

Effect of infection control measures on the frequency of diarrheal episodes in child care: a randomized, controlled trial.

BACKGROUND: Diarrheal infections are common in children who attend child care, and preventing transmission of disease in this setting depends on actions by child care staff. We set out to discover whether transmission of gastrointestinal infections in child care could be reduced by improved infection control procedures. METHODS: We performed a cluster randomized, controlled trial of an infection control intervention conducted in child care centers for 1 city in Australia. The intervention was training of child care staff about transmission of infection and handwashing and focused on both staff and child behavior. Implementation of the intervention was recorded by an observer. Illness was measured by parent report in telephone interviews every 2 weeks. RESULTS: There were 311 child-years of surveillance for diarrheal episodes. The rate of episodes of diarrhea was 1.9 per child-year in intervention centers and 2.7 per child-year in control centers. Multivariable analysis showed that diarrheal episodes were significantly reduced in intervention center children by 50%. However, the impact of the intervention was confined to children over 24 months of age. For those centers in which children's compliance with handwashing was high, diarrheal episodes were reduced by 66%. CONCLUSIONS: This trial supports education about infection control, for staff and children in child care, as a means of reducing transmission of diarrhea. Reduction in episodes of diarrhea in children in child care was limited to children over 24 months of age.

Australian Capital Territory↗
PubMed2000

A time to be born.

OBJECTIVES: This study used a large, population-based data set (n = 619,455) to establish reference standards of the timing of spontaneous vaginal births. METHODS: Low-risk births in Massachusetts from 1989 to 1995 were studied. This group comprised 242,276 births that met the following criteria: singleton, vertex, vaginal births with a birthweight of between 2500 and 4000 g; gestation between 37 and 42 weeks; a 5-minute Apgar score greater than 6, and no induction or stimulation. RESULTS: Low-risk births displayed a mild circadian pattern, with a peak between 11:00 AM and 1:00 PM and a trough between 11:00 PM and 1:00 AM. Subgroup analysis showed no clear differences except for parity. CONCLUSIONS: Reference standards should be developed and used as comparative norms for hospital and practice-based perinatal studies of diurnal patterns of birthing.

Circadian Rhythm↗
PubMed2000

Vision and low self-rated health: the Blue Mountains Eye Study.

PURPOSE: To assess the relationship between reduced vision and low self-rating of global health, after taking into account many other related factors. METHODS: The Blue Mountains Eye Study examined 3654 residents aged > or =49 years (82.4% response) in an area west of Sydney, Australia. Presenting and best-corrected visual acuity (VA) were measured before and after refraction using a LogMAR chart. During a face-to-face interview, self-rated health was assessed by asking: "For someone of your age, how would you rate your overall health?: excellent, good, fair, or poor." Information about demography, socioeconomic status, need for assistance in daily living activities, medical history, and health risk behaviors was also collected. Logistic regression analyses were performed after dichotomizing self-rated health as poor or fair (low) versus good or excellent. RESULTS: Among persons without visual impairment (defined from best-corrected VA in the better eye), 24.5% rated their health as either poor or fair, compared with 35.5% and 48.8% of persons with mild or moderate-to-severe visual impairment, respectively. In multivariate logistic regression models that included 17 other related factors, reduced vision was statistically significantly associated with lower self-rated health in persons aged <80 years. For each one-line (5 letter) reduction in best-corrected VA, there was 20% increased likelihood of low self-rated health, after adjustment for other factors found associated with self-rated health (multivariate-adjusted odds ratio 1.2, 95% confidence interval 1.1-1.3). In persons aged 80 years or older, reduced vision had no impact on global health rating. CONCLUSIONS: Decreased vision was found to have an independent impact on global health ranking by persons younger than age 80 years, but not by older persons in this population. Taking into account many other factors affecting perceived health, people younger than age 80 years who see well are also more likely to say that they feel well!

Activities of Daily Living↗
PubMed2000

Canine visceral leishmaniasis in Sicily.

The Sicilian province of Catania is an active foci for human visceral leishmaniasis (VL) in the Mediterranean area. Approximately 10 to 15 cases of VL are diagnosed via hospital admissions each year in this community. Recently, an increase in VL case reporting by Sicilian physicians was noted, with 38 and 37 VL cases in 1996 and 1997, respectively. Before 1995, there were no reported VL cases among U.S. military personnel or their family members living in Sicily. However, since 1996, there have been four cases referred to Walter Reed Army Medical Center for diagnosis and treatment, all involving the children of personnel assigned to Naval Air Station Sigonella. Exposure histories for all infected individuals excluded exposure to Leishmania parasites outside of Sicily. All patients lived in areas where vectoring sandflies are present. All had dogs as family pets. To evaluate the level of infection among dogs owned by Navy personnel and their families, U.S. Navy Environmental and Preventive Medicine Unit 7, in a collaborative study with the U.S. Army Veterinary Clinic, Naval Air Station Sigonella, and the Walter Reed Army Institute of Research, performed clinical evaluation and serological testing of 50 dogs residing with U.S. personnel assigned to Naval Air Station Sigonella. The data indicate a high exposure rate to Leishmania (60% of the animals tested had elevated immunoglobulin M antibody levels) in the study population, suggesting that they were infected with Leishmania infantum. Distribution of seropositive dogs by sex was equal. Most of the dogs studied appeared to be in good health. However, inapparent infection of dogs, seen by Italian veterinarians, has been observed throughout all areas of Catania. Sandflies responsible for vectoring L. infantum were trapped in the same locations as the dogs sampled in this study. The level of subclinical infection was 75% among seropositive dogs. The overall level of canine infection observed was higher than expected. This study demonstrates an increased risk to military working dogs and companion dogs of U.S. personnel for infection with L. infantum during a 2- to 3-year tour in Sicily.

Animals↗
PubMed1999

Spondyloepimetaphyseal dysplasia with joint laxity (SEMDJL): presentation in two unrelated patients in the United States.

This is a report of two North American patients with spondyloepimetaphyseal dysplasia with joint laxity, an uncommon autosomal recessive skeletal dysplasia rarely reported outside of South Africa. Patients with SEMDJL have vertebral abnormalities and ligamentous laxity that results in spinal misalignment and progressive severe kyphoscoliosis, thoracic asymmetry, and respiratory compromise resulting in early death. Nonaxial skeletal involvement includes elbow deformities with radial head dislocation, dislocated hips, clubbed feet, and tapered fingers with spatulate distal phalanges. Many affected children have an oval face, flat midface, prominent eyes with blue sclerae, and a long philtrum. Palatal abnormalities and congenital heart disease are also observed. Diagnosis in infancy may be difficult because many of the typical findings are not apparent early and only evolve over time. We review the physical and radiographic findings in two unrelated patients with this disorder in order to increase the awareness of this disorder, particularly for clinicians outside of South Africa.

Child↗
PubMed1999

The failing Fontan with atrial flutter: a successful surgical option.

Two successful cases of eliminated atrial flutter and improved clinical status for Fontan patients are presented. An operation combining introduction of an extracardiac conduit for the Fontan connection, to direct all systemic venous blood away from the atrium, and atrial pathway division and cryoablation, is a useful surgical option for failing Fontan patients.

Adolescent↗
PubMed1999

Dietary antioxidants and age-related maculopathy: the Blue Mountains Eye Study.

OBJECTIVE: To assess associations between the stages of age-related maculopathy (ARM) and dietary intake of carotene, vitamin C, retinol, and zinc. DESIGN: Cross-sectional, population-based study. PARTICIPANTS: A total of 3654 subjects 49 years of age and older from a defined area, west of Sydney, Australia, participated. A total of 2900 participants (79.4%) completed accurate food records. INTERVENTION: Masked grading of stereoscopic macular photographs, detailed interviewer-administered questionnaire, and 145-item self-administered food frequency questionnaire. MAIN OUTCOME MEASURES: Late ARM and early ARM were diagnosed from photographic grading. RESULTS: The authors found no statistically significant associations between ARM and dietary intake of either carotene, zinc, or vitamins A or C, either from diet or supplements or from the combined intake from diet and supplements. Multivariate-adjusted odds ratios (95% confidence interval) were calculated comparing highest to lowest dietary intake quintiles. For late ARM, the odds ratios were carotene, 0.7 (range, 0.3-2.0); vitamin A, 1.2 (range, 0.5-3.3); vitamin C, 1.3 (range, 0.5-3.4); and zinc, 1.0 (range, 0.4-2.8). For early ARM, the odds ratios were carotene, 0.7 (range, 0.4-1.1); vitamin A, 1.2 (range, 0.7-2.0); vitamin C, 0.9 (range, 0.5-1.4); and zinc, 0.8 (range, 0.5-1.3). No significant trends were apparent. Adjustment for energy intake also showed no associations between these antioxidants and ARM. Further, no associations were found between increasing intake of foods high in antioxidant vitamins and decreasing prevalence of either late or early ARM. CONCLUSIONS: The authors found no associations between ARM and dietary antioxidants, either from diet alone or including supplements, or from selected foods, in the Blue Mountains Eye Study population.

Aged↗
PubMed1999

Use of eye care services by older Australians: the Blue Mountains Eye Study.

PURPOSE: To assess utilization of eye care services in an older Australian population. METHODS: The Blue Mountains Eye Study examined 3654 permanent residents aged 49 years or older from two New South Wales postcode areas. At interview, we collected information about past attendance to eye care practitioners, demographic and socio-economic status variables and past medical and eye history. Full-time optometric and part-time ophthalmic services were available in this community. RESULTS: Almost all participants (99%) had seen either an ophthalmologist or optometrist in the past, with 62, 27, 7 and 3% having last attended in the last 2, 2-5, 5-10 and > 10 years, respectively. Among those participants (2251) who had been seen in the last 2 years, 50.2% (1131) last saw an ophthalmologist, 48.6% (1094) last saw an optometrist and 26 (1.2%) could not state whom they saw. After adjusting for age and sex, factors statistically significantly associated with attending an ophthalmologist included older age, female gender, higher socio-economic status, moderate to high myopia and presence of systemic disease (diabetes, hypertension) or any significant eye pathology. Factors statistically significantly associated with attending an optometrist were younger age, living alone, not currently married, being able to go out alone, having better presenting visual acuity, hyperopia and absence of diabetes or significant eye pathology, including moderate to high myopia. CONCLUSIONS: Findings from this study indicate that whether people use eye care services and whom they visit is mainly driven by need factors. Although there was considerable overlap, this study found relatively appropriate utilization of eye care services by this population.

Age Distribution↗
PubMed1999

Raman and infrared studies of nucleosides at high pressures: I. Adenosine.

Room temperature Raman and infrared (IR) spectra of crystalline adenosine at pressures between 1 atm and 10 GPa are reported. Vibrational modes were identified through assignments in the literature. Many modes were found to increase in frequency with pressure; however, some irregularities were observed. Discontinuities were observed in numerous Raman and IR modes near 2.5 GPa, indicating a phase transition. The modes associated with the glycosidic bond shift significantly down in frequency near this pressure, suggesting a weakening of the associated bond. The IR modes associated with hydrogen-stretching motions were found to decrease in frequency with pressure.

Adenosine↗
PubMed1999

Factors associated with use of community support services in an older Australian population.

OBJECTIVE: To assess prevalence and risk factors associated with use of community support services in a representative older Australian population. METHODS: The Blue Mountains Eye Study surveyed 3,654 people aged > or = 49 years, 82.4% of eligible residents from an area west of Sydney during 1992-94. Questions about use of community support services were asked during face-to-face interview. Information on marital and living status, socio-economic status measures, past medical history and self-ranked health status were also collected. RESULTS: 186 (5.4%) persons including 124 women (6.3%) and 62 men (4.2%) reported regular use of community support services, including Meals-on-Wheels (n = 52), Home Care (n = 147) or visits from a community nurse (n = 63). All three services were used by 17 persons and two services by 42 persons. There was a marked age-related increase in use of services from 1.8% in persons aged < 60 years to 25.3% in persons aged 80+ years. Factors significantly associated with use of community services in a multivariate model were: age (OR 1.7 per age decade), living alone (OR 2.5), walking disability (OR 4.1), visual impairment (OR 3.0), stroke history (OR 2.2), arthritis history (OR 1.8), low perceived health status (OR 1.7), cancer history (OR 1.7) and a history of any falls in the past 12 months (OR 1.6). CONCLUSIONS: Our study has found a wide range of health-related factors that impact on the use of community support services, particularly conditions causing difficulty in walking. IMPLICATIONS: These data may assist health planners in identifying target populations for the provision of community support services.

Age Distribution↗