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Biomedical subjects

Andrew Hall

Publications and source records attributed to Andrew Hall.

13 recordsLinked to original sources
PubMed2006

Effect on weight gain of routinely giving albendazole to preschool children during child health days in Uganda: cluster randomised controlled trial.

OBJECTIVE: To estimate the effectiveness of delivering an anthelmintic through a community child health programme on the weight gain of preschool children in Uganda. DESIGN: Cluster randomised controlled trial. SETTING: Eastern Uganda. PARTICIPANTS: 48 parishes participating in a new programme for child health: 24 offered children an additional service of anthelmintic treatment. The outcome is based on measurements from 27,995 children. INTERVENTION: Treatment of children aged between 1 and 7 years with 400 mg albendazole added to standard services offered during child health days over a three year period. MAIN OUTCOME MEASURE: Weight gain. RESULTS: The provision of periodic anthelmintic treatment as a part of child health services in Uganda resulted in an increase in weight gain of about 10% (166 g per child per year, 95% confidence interval 16 to 316) above expected weight gain when treatments were given twice a year, and an increase of 5% when the treatment was given annually. CONCLUSION: Deworming of preschool children in Uganda as part of regularly scheduled health services seems practical and associated with increased weight gain.

Albendazole↗
PubMed2006

Remote controlled magnetically guided pulmonary vein isolation in canines.

BACKGROUND: Ablation of atrial fibrillation (AF) remains a challenging procedure fraught with significant risks and technical difficulties. A magnetically guided catheter system has been developed that potentially addresses many of these challenges. Fully remote controlled electrical isolation of pulmonary veins was performed in canines, facilitated by a three-dimensional computed tomogram (CT) that depicted the anatomic relationships of the pulmonary veins and the left atrium. OBJECTIVE: The purpose of this study was to evaluate the feasibility of pulmonary vein isolation with a novel remote controlled magnetically guided catheter. METHODS: CT scans were obtained in seven healthy male canines. A 7-Fr irrigated magnetic catheter was advanced transseptally to the left atrium. A magnetic guidance system was used to control the orientation of the catheter tip. A mechanical device advanced or retracted the catheter as needed. Pulmonary venography was performed and compared with the CT scan. The CT scan was used as a visual reference to set the magnetic field vectors. Radiofrequency energy was delivered through the irrigated magnetic catheter to isolate the superior pulmonary veins, as judged by elimination of pulmonary vein potentials. RESULTS: The isolation procedure was successful in all 14 pulmonary veins, and there was no evidence of stenosis at 80-100 days postprocedure. CONCLUSIONS: These results demonstrate that remote controlled catheter ablation is safe and effective for segmental pulmonary vein isolation. This technology could facilitate curative ablation of AF in humans and reduce the occupational hazards to the operator of prolonged procedures and radiation exposure.

Animals↗
PubMed2006

Complete CO oxidation over Cu2O nanoparticles supported on silica gel.

We find that nearly monodisperse copper oxide nanoparticles prepared via the thermal decomposition of a Cu(I) precursor exhibit exceptional activity toward CO oxidation in CO/O2/N2 mixtures. Greater than 99.5% conversion of CO to CO2 could be achieved at temperatures less than 250 degrees C for over 12 h. In addition, the phase diagram and pathway for CO oxidation on Cu2O (100) is computed by ab initio methods and found to be in qualitative agreement with the experimental findings.

Carbon Monoxide↗
PubMed2005

Long-term efficacy of hepatitis B vaccine, booster policy, and impact of hepatitis B virus mutants.

The long-term efficacy of hepatitis B vaccine, long-term effectiveness of hepatitis B immunisation programmes, immune memory induced by hepatitis B vaccine, current booster policies, and impact of hepatitis B virus mutants on immunisation programmes were reviewed at the Viral Hepatitis Prevention Board (VHPB) meeting in Sevilla, Spain, March 2004. The main focus was on universal vaccination programmes with data being presented from Italy, Saudi Arabia, Singapore, Spain, Taiwan, Thailand, The Gambia, and USA (Alaska).

DNA, Viral↗
PubMed2005

A preliminary investigation of a spectroscopic technique for the diagnosis of natural caries lesions.

OBJECTIVE: To report the use of spectroscopic analysis of dental fluorescence excited with a blue InGaN laser diode operating at 405 nm. METHOD: The spectra resulting from three classifications of smooth surface non-cavitated caries lesions (dull, shiny, brown) with 20 samples in each group were examined using the ratio of integrated fluorescence intensity in two spectral bands. RESULTS: All lesions demonstrated spectra which were significantly different from sound tooth structure. As expected, the 'brown' lesions demonstrated a significantly different spectral profile from the two white spot lesion classifications. Dull and shiny lesions had significantly different spectral measurements when examining the ratio of the integrated fluorescence in spectral bands between 480-500 and 620-640 nm. CONCLUSION: This method has application for detection of dental caries as well as demonstrating potential application to evaluate lesions which may represent different degrees of caries activity.

Analysis of Variance↗
PubMed2005

Detecting mismatch repair defects in myeloma.

Defects in the mismatch repair system are associated with a microsatellite unstable phenotype. In this chapter, we describe the preparation of purified plasma cells using CD138 magnetic microbeads as a source of tumor DNA. We also describe a robust, sensitive method for comparing microsatellite repeat units of tumor to constitutive DNA using polymerase chain reaction and laser scanning of fluorescently labeled amplicons in an automated sequencer in order to assess microsatellite instability in myeloma.

Antigens, CD↗
PubMed2004

Weekly iron supplements given by teachers sustain the haemoglobin concentration of schoolchildren in the Philippines.

OBJECTIVES: To examine the effectiveness of weekly iron supplements given for 10 weeks by teachers to children in rural schools in the Philippines. METHODS: Forty-nine rural primary schools took part in the study and were randomly assigned to two groups: children in 25 schools received a weekly tablet providing 108 mg iron while children in 24 schools acted as controls. All children were dewormed before the start of the iron supplementation. The haemoglobin concentration of a systematic sample of one in three children in two classes in each school was estimated before and 5-17 weeks after the end of the iron supplementation. RESULTS: A total of 1510 children aged 7-12 years were studied at both surveys. The mean haemoglobin concentration of children in the intervention group did not change significantly; in the untreated group it fell by 3.8 g/l and the prevalence of anaemia rose from 14.3% to 25.6%. The difference between study groups was significantly larger amongst the younger children (7-8 years), and was observed in both anaemic and non-anaemic children. CONCLUSION: Even where anaemia is only a mild public health problem, weekly iron supplements given by teachers may prevent a fall in the haemoglobin concentration, and can benefit both anaemic and non-anaemic children.

Aging↗
PubMed2003

Ill-health reported by schoolchildren during questionnaire surveys in Ghana, Mozambique and Tanzania.

BACKGROUND: Insufficient attention has been paid to the health problems of school-age children in sub-Saharan Africa. A questionnaire administered to schoolchildren about their ill-health has been developed to identify schools in which urinary schistosomiasis occurs. The data collected during the interviews can also be used to assess other common health problems. OBJECTIVES: To analyse data collected during health questionnaires in schools to assess how schoolchildren perceive their own health, and to compare the findings between three countries in sub-Saharan Africa. METHODS: Questionnaires asking about recent health problems were administered by teachers to schoolchildren in 120 primary schools in Mozambique, 52 primary schools in Tanzania and 298 primary schools in Ghana. A total of 67 002 children aged 8-15 years took part. RESULTS: Of the 10 health problems asked about in all questionnaires, the average number reported by each child was 3.9 in Ghana, 3.4 in Mozambique and 3.1 in Tanzania. The distributions of the prevalence of each condition among schools were similar and the prevalence of all conditions showed a similar ranking. For most conditions a greater percentage of girls than boys reported each health problem. CONCLUSIONS: Schoolchildren in Ghana, Mozambique and Tanzania do not perceive themselves to be healthy. The pattern of reported health problems was similar in each country. School health questionnaires are worthy of further study and validation.

Adolescent↗
PubMed2002

Novel, magnetically guided catheter for endocardial mapping and radiofrequency catheter ablation.

BACKGROUND: Ablation of complex arrhythmias would be greatly facilitated by more precise control of ablation catheters. A feasibility study was performed in animals to evaluate a novel magnetic guidance system (MGS) that generates a magnetic field to control the movement and position of a magnetic ablation catheter. METHODS AND RESULTS: The MGS is composed of a digital biplanar fluoroscope within an array of superconducting electromagnets that surround the torso of the experimental animal and a computer control system that generates a composite magnetic field for directional catheter deflection. Magnetic catheter navigation was performed in dogs and pigs (20 to 30 kg). A 7F magnetic ablation catheter was used for intracardiac navigation and radiofrequency ablation. The performance of a standard 7F deflectable catheter was not affected by the MGS. The magnetic catheter was navigated successfully to 51 predefined targets throughout the heart in 6 animals. In 5 animals, the magnetic catheter, guided by a 3D computed tomogram, was successfully navigated to all pulmonary veins. Navigation accuracy was estimated as <1 mm displacement from the target. The magnetic catheter was used to ablate the atrioventricular node in 4 animals and to perform linear ablations across the endocardial surface underlying an epicardial multielectrode recording plaque in 4 animals. CONCLUSIONS: These results demonstrate that the MGS can navigate and stabilize an ablation catheter at endocardial targets. Linear or focal radiofrequency ablation with the magnetic catheter is not compromised by the magnetic field. This technology provides precise control of endocardial catheters.

Animals↗
PubMed2002

Observational study of vaccine efficacy 14 years after trial of hepatitis B vaccination in Gambian children.

OBJECTIVE: To determine the duration of protection from hepatitis B vaccine given in infancy and early childhood. DESIGN: Cross sectional serological study of hepatitis B virus infection in children of various ages 14 years after the start of a trial of vaccination regimens. SETTING: Two villages in the Gambia. PARTICIPANTS: Children and adolescents given hepatitis B vaccine in infancy or early childhood: 232 were aged 1-5 years, 225 aged 5-9 years, 220 aged 10-14 years, and 175 aged 15-19 years. MAIN OUTCOME MEASURES: Vaccine efficacy against infection and against chronic infection in the different age groups. RESULTS: Vaccine efficacy against chronic carriage of hepatitis B virus was 94% (95% confidence interval 89% to 97%), which did not vary significantly between the age groups. Efficacy against infection was 80% (76% to 84%). This was significantly lower in the oldest age group (65%, 56 to 73). Of the uninfected participants in this age group, 36% had no detectable hepatitis B virus surface antibody. Time since vaccination and a low peak antibody response were the most powerful risk factors for breakthrough infection (P<0.001 in each case). Low peak antibody response was also a risk factor for chronic carriage (odds ratio 95, 19 to 466). CONCLUSIONS: Children vaccinated in infancy are at increased risk of hepatitis B virus infection in the late teens. The risk of chronic carriage after sexual exposure needs further assessment to determine if booster vaccines are necessary.

Adolescent↗
PubMed2002

A randomised trial in Mali of the effectiveness of weekly iron supplements given by teachers on the haemoglobin concentrations of schoolchildren.

OBJECTIVE: To assess the effect on the haemoglobin concentrations of schoolchildren of weekly iron tablets administered by teachers. DESIGN: Sixty schools were randomly assigned to two groups: in 30 schools children were given weekly for 10 weeks a tablet providing 65 mg of iron and 0.25 mg of folic acid; in the other 30 schools no iron tablets were given. All children were dewormed and given vitamin A before the study began. The haemoglobin concentration of up to 20 randomly selected children in each school was estimated before and 2 weeks after the end of treatment. SETTING: Rural community schools in Kolondieba district of Mali. SUBJECTS: Some 1113 schoolchildren aged 6-19 years with a mean of 11.4 years. RESULTS: The haemoglobin concentration of treated children rose on average by 1.8 g l(-1) and the prevalence of anaemia fell by 8.2%; in untreated children the haemoglobin concentration fell by an average of -2.7 g l(-1) and the prevalence of anaemia rose by 9.4%. The fall in haemoglobin concentration among untreated girls of -4.0 g l(-1) was greater than in untreated boys (-0.3 g l(-1) ). CONCLUSIONS: Weekly iron tablets given by teachers prevented a general fall in the haemoglobin concentrations of untreated children, and led to a small but statistically significant rise among treated children. Young children benefited more than children aged >or=12 years, and girls benefited more than boys.

Adolescent↗
PubMedDate not supplied

Beyond deworming.

Explore the source record for details and available documents.

Anemia↗