Biomedical subjects

A Hodgson

Publications and source records attributed to A Hodgson.

At least 19 recordsLinked to original sources

PubMed2007

Using lay counsellors to promote community-based voluntary counselling and HIV testing in rural northern Ghana: a baseline survey on community acceptance and stigma.

Access to voluntary counselling and HIV testing (VCT) remains limited in most parts of Ghana with rural populations being the least served. Services remain facility-based and employ the use of an ever-dwindling number of health workers as counsellors. This study assessed approval for the use of lay counsellors to promote community-based voluntary counselling and testing for HIV and the extent of HIV/AIDS-related stigma in the Kassena-Nankana district of rural northern Ghana. A cross-sectional questionnaire survey was conducted. Logistic regression was used to identify predictors of the tendency to stigmatize people living with HIV/AIDS (PLWHAs). Focus group discussions were held and analytical coding of the data performed. The majority (91.1%) of the 403 respondents indicated a desire to know their HIV status. Most (88.1%) respondents considered locations outside of the health facility as preferred places for VCT. The majority (98.7%) of respondents approved the use of lay counsellors. About a quarter (24%) of respondents believed that it was possible to acquire HIV through sharing a drinking cup with a PLWHA. About half (52.1%) of the respondents considered that a teacher with HIV/AIDS should not be allowed to teach, while 77.2% would not buy vegetables from a PLWHA. Respondents who believed that sharing a drinking cup with a PLWHA could transmit HIV infection (OR 2.50, 95%CI 1.52-4.11) and respondents without formal education (OR 2.94, 95%CI 1.38-6.27) were more likely to stigmatize PLWHAs. In contrast, respondents with knowledge of the availability of antiretroviral (ARV) drugs were less likely to do so (OR 0.40, 95%CI 0.22-0.73). Findings from the thirteen focus group discussions reinforced approval for community-based VCT and lay counsellors but revealed concerns about stigma and confidentiality. In conclusion, community-based VCT and the use of lay counsellors may be acceptable options for promoting access. Interventional studies are required to assess feasibility and cost-effectiveness.

Adult↗

PubMed2006

Water desorption from an oxygen covered Pt(111) surface: multichannel desorption.

Mixed OH/H2O structures, formed by the reaction of O and water on Pt(111), decompose near 200 K as water desorbs. With an apparent activation barrier that varies between 0.42 and 0.86 eV depending on the composition, coverage, and heating rate of the film, water desorption does not follow a simple kinetic form. The adsorbate is stabilized by the formation of a complete hydrogen bonding network between equivalent amounts of OH and H2O, island edges, and defects in the structure enhancing the decomposition rate. Monte Carlo simulations of water desorption were made using a model potential fitted to first-principles calculations. We find that desorption occurs via several distinct pathways, including direct or proton-transfer mediated desorption and OH recombination. Hence, no single rate determining step has been found. Desorption occurs preferentially from low coordination defect or edge sites, leading to complex kinetics which are sensitive to both the temperature, composition, and history of the sample.

Journal Article↗

PubMed2006

Unmet need for essential obstetric services in a rural district in northern Ghana: complications of unsafe abortions remain a major cause of mortality.

AIM: The aim of this study was to review 4 years of hospital data on antenatal services, deliveries and maternal deaths as the baseline evaluation for a programme to improve care. METHODS: Descriptive analyses were made of data extracted from the monthly returns charts and clinical notes on all maternal deaths from January 2001 to December 2003 at the district hospital in the Kassena-Nankana district of rural northern Ghana. RESULTS: The majority (56.6%) of women first attended an antenatal clinic during the second trimester, and about 70% had haemoglobin levels of <10 g/dl. A total of 3160 deliveries were recorded. The prevalence of female genital cutting was 21.4%. Hospital and population rates of Caesarean section were 9.1 and 1.8%, respectively. Only one-third of women in need of a Caesarean section were able to access this intervention. Twenty-four maternal deaths were recorded, giving a hospital maternal mortality ratio of 759 per 100,000 live births. Complications of unsafe abortion (29.1%) and haemorrhage (20.8%) were the leading causes of death. Seventy-one percent of deaths occurred in women living within 15 km of the district hospital, and 50% occurred within 24 h of arrival. CONCLUSION: Late recourse to the health facility and complications of unsafe abortion are major contributory factors to maternal mortality in this district. A high level of unmet need for essential obstetric services, including access to contraceptive services, exists in this district. Decentralizing the availability of essential obstetric services through health centres to community level is necessary to reduce maternal mortality in developing countries.

Abortion, Induced↗

PubMed2006

Trend and causes of neonatal mortality in the Kassena-Nankana district of northern Ghana, 1995-2002.

OBJECTIVES: To describe the trend and causes of neonatal deaths in a rural district in northern Ghana. METHODS: Descriptive analysis of data collected from the Navrongo Demographic Surveillance System and verbal autopsies conducted on all neonatal deaths from 1995-2002. RESULTS: Of 1118 recorded neonatal deaths 1068 (95.5%) could be analysed. Only 13.2% of deaths occurred at the health facility; 62.7% occurred in the early neonatal period, with prematurity (38%) and birth injuries (19%) as leading causes. Infectious causes (66%) were the major contributors to late neonatal deaths. Infanticide accounted for 4.9% of all neonatal deaths. The cause-specific mortality rate for neonatal tetanus remained under 2.5% throughout the 8-year period. Overall, the neonatal mortality rate declined at an average of 2.5 per 1000 live births per year: Down by nearly 50% from 40.9 (95%C.I. 34.1-46.8) in 1995 to 20.5 (95%C.I.17.3-22.7) in 2002. CONCLUSION: The various health interventions undertaken in this district have had the collateral effect of causing decline in neonatal mortality. Neonatal mortality could be further reduced by preventing and treating neonatal infections, having skilled attendance at delivery and the elimination of infanticide. Data from demographic surveillance sites may be useful in monitoring trends in child mortality.

Birth Injuries↗

PubMed2005

The structure and crystallization of thin water films on Pt(111).

When water is adsorbed on Pt(111) above 135 K several different ice structures crystallize, depending on the thickness of the ice layer. At low coverage water forms extended islands of ice with a (square root(37) x square root(37))R25(o) unit cell, which compresses as the monolayer saturates to form a (square root(39) x square root(39))R16(o) structure. The square root(39) low-energy electron diffraction (LEED) pattern becomes more intense as the second layer grows, remaining bright for films up of 10-15 layers and then fading and disappearing for films more than ca. 40 layers thick. The ice multilayer consists of an ordered square root(39) wetting layer, on which ice grows as a crystalline film which progressively loses its registry to the wetting layer. Ice films more than ca. 50 layers thick develop a hexagonal LEED pattern, the entire film and wetting layer reorienting to form an incommensurate bulk ice. These changes are reflected in the vibrational spectra which show changes in line shape and intensity associated with the different ice structures. Thin amorphous solid water films crystallize to form the same phases observed during growth, implying that these structures are thermodynamically stable and not kinetic phases formed during growth. The change from a square root(39) registry to incommensurate bulk ice at ca. 50 layers is associated with a change in crystallization kinetics from nucleation at the Pt(111) interface in thin films to nucleation of incommensurate bulk ice in amorphous solid water films more than 50 layers thick.

Journal Article↗

PubMed2005

The structure of the mixed OH + H2O overlayer on Pt[111].

The structure of the mixed p(3 x 3)-(3OH + 3H2O) phase on Pt[111] has been investigated by low-energy electron diffraction-IV structure analysis. The OH + H2O overlayer consists of hexagonal rings of coplanar oxygen atoms interlinked by hydrogen bonds. Lateral shifts of the O atoms away from atop sites result in different O-O separations and hexagons with only large separations (2.81 and 3.02 angstroms) linked by hexagons with alternating separations of 2.49 and 2.813.02 angstroms. This unusual pattern is consistent with a hydrogen-bonded network in which water is adsorbed in cyclic rings separated by OH in a p(3 x 3) structure. The top-most two layers of the Pt atoms relax inwards with respect to the clean surface and both show vertical buckling of up to 0.06 angstroms. In addition, significant shifts away from the lateral bulk positions have been found for the second layer of Pt atoms.

Journal Article↗

PubMed2005

Doses from the consumption of Cardiff Bay flounder containing organically bound tritium.

ICRP dose coefficients for the ingestion of organically bound tritium (OBT) by adults and children are intended for general application to unspecified forms in diet and may not be applicable to intakes of a specific form of OBT. To obtain information relating to OBT in fish from Cardiff Bay, the retention of tritium in adult rats was determined after administration as either tritiated water (HTO) or dried flounder flesh containing OBT. Two components of retention were obtained in each case. The first component, attributable to tritium equilibrating with body water, had a half-time of retention of 3 days in each case, and accounted for 97% of the intake as HTO and 70% after intake of OBT in flounder. Results were consistent with rapid catabolism of a large proportion of flounder OBT to HTO. The second component of retention, attributable to OBT in rat tissues, accounted for 3% of tritium intake as HTO and 30% after intake as flounder OBT; the half-times of retention were 10 days and 25 days, respectively. The results obtained after administration as HTO are consistent with published animal data and correlate with the ICRP assumptions for adult man of half-times of 10 days for 97% behaving as HTO in body tissues and 40 days for 3% incorporated into OBT in body tissues. The results obtained after administration of flounder OBT suggest that appropriate assumptions for retention in adult man are 70% with a 10 day half-time and 30% with a 100 day half-time. These assumptions result in an ingestion dose coefficient of 6 x 10(-11) Sv Bq(-1). This compares with the ICRP value for OBT ingestion by adults of 4.2 x 10(-11) Sv Bq(-1), based on half-times of 10 days and 40 days applied to equal proportions of retained tritium. It is proposed that a dose coefficient of 6 x 10(-11) Sv Bq(-1) should be applied to tritium in flounders from Cardiff Bay. It is further proposed that this dose coefficient should be applied to all ingestion intakes by adults relating to this source of exposure, unless specific information is available showing that a significant proportion of the intake is HTO. The same proposals apply to dose coefficients derived here for flounder OBT consumption by children.

Animals↗

PubMed2005

Voluntary counseling and HIV testing for pregnant women in the Kassena-Nankana district of northern Ghana: is couple counseling the way forward?

This study reports the results of a cross-sectional questionnaire survey undertaken in the Kassena-Nankana district of Ghana to assess the perception and attitude of 270 antenatal clinic attendants towards voluntary counseling and HIV testing. It was found that although 92.6% (95% CI 88.8-95.4) of respondents indicated a willingness to get tested, only 51% (95% CI 45.0-57.2) considered HIV testing for pregnant women to be useful. Most (93.6%) indicated they would like their husbands (partners) to know the result of the test and 52.2% indicated that their husbands would be willing to accompany them to antenatal clinic (ANC) at least once during the pregnancy. The perception of the usefulness of HIV testing (OR = 8.5, 95% CI 1.8-40.0), the willingness to disclose test result to the husband (OR = 13.3, 95% CI 4.0-44.5) and perceived willingness of husband to accompany wife to antenatal clinic (OR = 5.2, 95% CI 1.4-19.8) were found to be independent predictors of a woman's willingness to get tested. The willingness to disclose test result to husband (OR 3.2, 95% CI 1.1-10.5) and knowledge of at least one mode of MTCT HIV transmission (OR = 2.1, 95% CI 1.2-3.6) were found to be independent predictors of a woman's perception that getting tested was useful. The results suggest that for pregnant women in this district, the willingness to get tested for HIV does not equate with the perception of the test's usefulness, and that spouses are likely to exert strong influence on the attitude of pregnant women towards VCT. Couple counseling facilitated through couple-friendly ANC services should be explored as strategy for the intended VCT program in this district.

Adult↗

PubMed2004

Hydrogen bonding in mixed OH+H2O overlayers on Pt(111).

The stability of OH on Pt(111) has been investigated to determine the role of hydrogen bonding in stabilizing the overlayer. We find that the optimal structure is a mixed (OH+H2O) phase, confirming recent density-functional theory predictions. The reaction O+3H(2)O forms a hexagonal (sqrt[3]xsqrt[3])R30 degrees -(OH+H2O) lattice with a weak (3x3) superstructure, caused by ordering of the hydrogen bonds. The mixed overlayer can accommodate a range of H(2)O/OH compositions but becomes less stable as the H2O content is reduced, causing defects in the hydrogen-bonding network that lift the (3 x 3) superstructure and destabilize the overlayer.

Journal Article↗

PubMed2004

Comparative absorption parameters of Pu and Am from PuO2 and mixed oxide aerosols measured after in vitro dissolution test and inhalation in rats.

PURPOSE: To compare specific absorption parameter values obtained from in vitro dissolution studies (this paper) and in vivo experiments (data published by Ramounet et al, 2000) and to determine their influence on Dose Per Unit Intake (DPUI) calculations. MATERIALS AND METHODS: Experiments were performed on plutonium oxide (PuO2) and two Mixed Oxide (MOx) preparations containing 5% Pu (w/w) made according to the industrial process in vitro using a static test and in vivo after rat inhalation. RESULTS: Behaviour of Pu and Am shows, in vitro, at shorter times, a greater rapid dissolution fraction f(r) for Pu (factor 10) and Am (factor 2) with MOx powders compared with PuO2, whereas in vivo results show a greater fraction f(r) for Pu (factor 5) and Am (factor 15) with PuO2 compared with MOx powders. This phenomenon has not been observed for slow dissolution absorption parameter s(s). The in vivo parameters for Pu and Am in these materials were very close to the default values recommended by International Commission for Radiological Protection for default Type S. CONCLUSIONS: Results obtained have shown that solubility of Pu from the mixed oxide was higher than that of Pu from PuO2. Nevertheless, no significant difference was observed between the three compounds in the corresponding dose coefficients in vivo or in vitro. Therefore, for these particular compounds, variation in the chemical composition of the aerosols had no significant influence on DPUI. Consequently, in vitro, the dissolution test can provide a good estimate of the in vivo behaviour. Studies of variation of % Pu (w/w) from MOx are in progress in our laboratory to confirm these conclusions.

Absorption↗

PubMed2004

Radionuclide biokinetics database (RBDATA-EULEP): an update.

The main activity of the RBDATA-EULEP project is the development of an electronic database of information on the biokinetics of radionuclides after intake by inhalation, ingestion or injection. It consists of linked tables of publications and experiments, with details and comments on the materials, procedures and results. By March 2004 it contained information on more than 1600 experiments from 600 publications. It will be extended and Internet access will also be provided.

Body Burden↗

PubMed2004

A randomized, comparative study of two regimens of beta-artemether for the treatment of uncomplicated, Plasmodium falciparum malaria, in northern Ghana.

In Ghana, wide-spread resistance to chloroquine has necessitated the drug's replacement as the first-line treatment for malaria, both to increase the likelihood of cure and to reduce transmission. To see if beta-artemether could be a suitable alternative to chloroquine, 223 adults (aged > or = 15 years) with uncomplicated, Plasmodium falciparum malaria were each given a total dose of 480 mg beta-artemether over 4 or 5 days. The patients were randomly allocated to receive an initial, loading dose of 80 or 160 mg, and were checked on days 1, 2, 3, 4 (or 5), 7 and 14, for fever clearance and any adverse events. Blood samples collected on days 0, 4 (or 5), 7 and 14 were smeared so that levels of parasitaemia could be evaluated. Haemoglobin concentrations on days 0 and 14 were also determined. In terms of the clinical cure 'rates' estimated in the intention-to-treat analysis (92.5% v. 97.4%) and the evaluability analysis (98.9% v. 100%), and of the frequency of parasitological cure by day 14 (97.0% v. 96.5%), the patients given an initial dose of 80 mg were similar to those given 160 mg as the loading dose. The regimen with the 160-mg loading dose appears as safe and as effective as the regimen with an initial dose of 80 mg. Since the regimen with the higher loading dose is shorter and involves fewer treatments than the other regimen, it would probably be associated with better compliance.

Adolescent↗

PubMed2003

Comparison of absorption after inhalation and instillation of uranium octoxide.

Values for the absorption parameters were compared after inhalation or intratracheal instillation of 1.5 microm mass median aerodynamic diameter (MMAD) 233U3O8 particles into the lungs of HMT strain rats. The two sets of parameter values were similar, as were the calculated dose coefficients and predicted biokinetics for workers. Hence the inhalation and instillation techniques can probably both be used to generate values of the absorption parameters for U3O8.

Absorption↗

PubMed2003

Optimising monitoring regimens for inhaled uranium oxides.

This paper provides guidance on the most appropriate monitoring procedures and intervals, the likely uncertainties in the assessment of intake and recommendations on appropriate investigation levels for repeated exposures to uranium trioxide, octoxide and dioxide of natural composition.

Absorption↗

PubMed2003

Biokinetics and assessment of intake of thorium dioxide.

The aim of this work was to investigate the biokinetics of thorium dioxide in animals for the purpose of assessing intakes of the compound by workers and the resulting doses. The results imply that measurements of the decay products in the chest or extrapolations from urine analysis data are unlikely to be of value for doses below 20 mSv. Even higher doses should be interpreted with caution as a consequence of uncertainties in particle size distribution and variations in dietary excretion.

Absorption↗

PubMed2003

Anomalies between radiological and chemical limits for uranium after inhalation by workers and the public.

Exposure limits for workers and the public are based on both chemical toxicity and radiation dose. As a consequence of the different procedures used in their calculation they are incompatible, and adherence to one limit may result in a serious breach of the other. This paper explores the background to these limits, the problems posed by their application and proposes how best to achieve compliance with both limits.

Air Pollutants, Radioactive↗

PubMed2003

Anomalously high excretion of Pu in urine following inhalation of plutonium nitrate?

A study of the biokinetics of inhaled plutonium nitrate in two volunteers has been carried out. Low doses (approximately 80 microSv) were achievable because tracers of high isotopic purity were used: 237Pu (measurable by X ray spectrometry) and 244Pu (measurable by accelerator mass spectrometry). Lung retention, amount in blood, uptake to the liver and skeleton, and urinary and faecal excretion were measured. The measured urinary excretion rates are about a factor of three higher than those predicted from urine excretion data measured following intravenous injection of plutonium to the same volunteers. If similar biokinetic behaviour occurs in workers exposed to plutonium nitrate, intakes by inhalation and corresponding committed doses assessed by urine bioassay could be consistently overestimated by a similar factor.

Administration, Inhalation↗

PubMed2003

RBDATA-EULEP: providing information to improve internal dosimetry.

The overall aim of the concerted action RBDATA-EULEP is to provide information to improve the assessments of intakes of radionuclides and of the resulting doses. This involves a review of the behaviour of radionuclides following intake, and the transfer of expertise on methodology by organising small training workshops. The main activity is the development of an electronic database, effectively an annotated bibliography, but the electronic format used facilitates extension, updating and information retrieval. It consists of linked tables of references and experiments, with details and comments on the materials, procedures and results. By June 2002 it contained information on 524 inhalation, 282 ingestion and 164 injection experiments from 391 references. It will be extended, and Internet access provided. Prospective users include groups developing standards for internal dosimetry, scientists conducting research on radionuclide biokinetics and health physicists assessing the consequences of accidental intakes.

Body Burden↗