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Biomedical subjects

B M Green

Publications and source records attributed to B M Green.

16 recordsLinked to original sources
PubMed2001

Long-term effectiveness of a peer-based intervention to promote condom and contraceptive use among HIV-positive and at-risk women.

OBJECTIVE: The authors used data from a larger study to evaluate the long-term effects of a peer advocate intervention on condom and contraceptive use among HIV-infected women and women at high risk for HIV infection. METHODS: HIV-infected women in one study and women at high risk for HIV infection in a second study were selected from the Women and Infants Demonstration Project and assigned to a standard or an enhanced HIV prevention treatment group. The enhanced intervention included support groups and one-on-one contacts with peer advocates tailored to clients' needs. The authors interviewed women at baseline and at 6-, 12- and 18-months, and measured changes in consistency of condom and contraceptive use and in self-efficacy and perceived advantages and disadvantages of condom and contraceptive use. RESULTS: Of HIV-infected women, the enhanced group had improved consistency in condom use, increased perceived advantages of condom use, and increased level of self-efficacy compared with the standard group. Of women at risk, the enhanced intervention group at six months maintained consistent condom use with a main partner and perceived more benefit of condom use compared with the standard group. These differences diminished at 12 months. CONCLUSIONS: The enhanced intervention was generally effective in the HIV+ study. In the at-risk study, however, intervention effects were minimal and short-lived. Factors related to the theory, intervention design, and sample characteristics help explain these differences.

Adolescent↗
PubMed1999

Distribution along a stages-of-behavioral-change continuum for condom and contraceptive use among women accessed in different settings. Prevention of HIV in Women and Infants Demonstration Projects.

The numbers of women of childbearing age in the US with HIV and AIDS from heterosexual transmission continues to rise. Behavioral interventions remain the best means of preventing transmission of HIV. Program planners often implement interventions to promote behavioral change in a wide range of settings such as family planning or sexually transmitted disease clinics, drug treatment facilities, or medical facilities that serve high risk and HIV positive women. Women recruited in different types of settings, however, may differ with respect to their experience with, attitudes toward, and willingness to use condoms and contraception. Such differences should be considered when tailoring interventions to the populations being served. We examined the readiness to use condoms and contraception among 3784 women in four cities recruited in three different types of settings: community, facilities not targeted to HIV positive women and medical facilities for HIV positive populations. Readiness to use condoms or contraception was measured using The Transtheoretical Model of Change. Women reported being in different stages along the continuum of condom and contraceptive use in the three settings. A greater proportion of women in the HIV-facility, 45%, had used condoms consistently for the previous 6 months compared to women in the other two settings (12% and 11%). Similarly, variation across settings was seen for contemplation of consistent contraceptive use to prevent unintended pregnancies. The variability in the distribution of condom and contraceptive use across settings underscores the importance of assessing the readiness for the behavior change and designing interventions that meet the specific needs of the populations being served.

Adolescent↗
PubMed1994

Residential radon exposure and lung cancer--an epidemiological study of Norwegian municipalities.

The study is based on a collaboration between the Cancer Registry of Norway, the Norwegian Radiation Protection Authority, and National Radiological Protection Board (NRPB, UK). The association between indoor radon exposure and lung cancer was studied in 427 municipalities. NRPB detectors were sent to 10,000 households, and 7,500 of the detectors were returned. Data from a nation-wide survey of smoking habits in 1964-1965 were available. Data on asbestos exposure were also used in a regression analysis. The reporting to the Cancer Registry of all new cases of cancer is fairly complete, as hospital departments and institutes of pathology are obliged to report all cancer cases. The histologically confirmed lung cancer cases were grouped into squamous-cell carcinoma, small-cell carcinoma, adenocarcinoma and other or non-specified histological types. The age-adjusted rate of lung cancer by histological type was the dependent variable in the regression analysis. A consistent increase in incidence of lung cancer was seen with increasing tobacco consumption, but no positive trend could be shown with increasing radon exposure in the descriptive presentation of the data. In the regression analysis, however, the incidence of small-cell anaplastic lung tumors in females increased significantly with increasing radon exposure. When based on the regression coefficients, the fraction of lung cancers attributable to radon is about 2-4%. However, systematic errors cannot be excluded in an ecological study such as presented here.

Adult↗
PubMed1993

Factors affecting indoor radon concentrations in the United Kingdom.

Data collected in a nationwide study on natural radiation exposure in UK dwellings (Wrixon et al. 1988) were re-analyzed to investigate the effects of rock type and various building and lifestyle characteristics, taken into account simultaneously, on indoor radon concentrations. A multiplicative model which takes into consideration the outdoor radon concentration is used. Indoor radon concentrations were found to be influenced by type of rock underlying the dwelling, double glazing, house type, floor level of rooms in which measurements were taken, window opening habits in the main bedroom, building materials used in the construction of the walls, floor type, and draught proofing. However, these eight factors together account for only 22% of the variation between dwellings. Estimates of the size of the effect associated with each factor are given.

Air Pollutants, Radioactive↗
PubMed1987

Reassortment of Thogoto virus (a tick-borne influenza-like virus) in a vertebrate host.

Reassortment is an important factor in the evolution of segmented genome viruses. For arthropod-borne viruses it is important to determine whether the vertebrate host acts as a site of reassortant virus formation since vertebrates often act as amplifying hosts. Mutants of Thogoto virus, a tick-borne orthomyxo-like virus, were shown to produce wild-type progeny in a dually infected permissive host (hamster), when hamsters were infected with two mutant viruses either by direct inoculation or by oral transmission from infected ticks. Viral dose and time of co-infection of the host affected the incidence of reassortment. This is the first report of reassortment of an arbovirus following infection of a vertebrate host via an arthropod vector.

Animals↗
PubMed1987

In vivo reassortment of Thogoto virus (a tick-borne influenza-like virus) following oral infection of Rhipicephalus appendiculatus ticks.

Arboviruses with segmented genomes have the potential to reassort in both their vertebrate hosts and arthropod vectors. Reassortment of Thogoto virus, a tick-borne orthomyxo-like virus, has been demonstrated following dual infection of hamsters by temperature-sensitive mutants. To investigate whether similar events can occur in ticks, Rhipicephalus appendiculatus larvae and nymphs were dually infected by interrupted feeding on viraemic hamsters. Wild-type reassortant virus was isolated from the ticks 12 to 15 days after engorgement. Following moulting, nymphs and adults transmitted reassortant virus to uninfected hamsters. This is the first reported evidence that a tick-borne arbovirus can reassort in vivo in a naturally infected arthropod vector. The relative roles of vector and vertebrate host in generating and perpetuating reassortant viruses in nature are discussed.

Animals↗
PubMed1985

The levels of radioactive materials in some common UK building materials.

Measurements have been made of the radon exhalation rates and radionuclide contents of some common UK building materials. These include concrete blocks incorporating pulverised fuel ash from coal-fired power stations as well as more traditional materials such as clay bricks and concrete blocks. Simple models are applied to the results to calculate the radiation exposure of people living in houses constructed with these materials. It is estimated that building materials make only a small contribution to the total radon concentration in most houses. A similarly small contribution to the effective dose equivalent received by people arises from the gamma-ray emission from building materials, and in most cases will exceed the contribution to the effective dose equivalent from the radon exhalation of those materials.

Construction Materials↗
PubMed1985

Surveys of natural radiation exposure in UK dwellings with passive and active measurement techniques.

A representative sample of over 2,000 UK dwellings was monitored for a year using thermoluminescent and etchable plastic dosemeters to measure gamma-ray dose rates and radon concentrations. The survey was carried out by post. Each householder completed a questionnaire on the type of dwelling and its characteristics. These data will be used in the assessment of the factors affecting indoor exposure. The mean gamma-ray dose rates were 0.062 and 0.057 microGy h-1 in air and the mean radon concentrations were 25 and 18 Bq m-3 for living areas and bedrooms respectively. Other results of the preliminary data analysis are given. More detailed surveys were conducted in areas where the local geology indicated that elevated exposures to natural radiation might occur. Over 800 dwellings were visited and measurements made of several parameters. The mean gamma-ray dose rates varied from 0.05 to 0.10 microGy h-1 in air. The mean radon concentrations varied from 14 Bq m-3 to 520 Bq m-3. Other findings related to equilibrium factors and regional differences are discussed.

Environmental Exposure↗
PubMed1983

Radon daughter exposures in the U.K.

Exposure due to the inhalation of the short-lived daughters of 222Rn is the single largest contributor to the exposure of the U.K. population. A survey of dwellings situated largely in the centers of population indicates an annual exposure of 0.16 WLM, on the average. On the basis of current knowledge this is equivalent to an annual effective dose equivalent of 800 mu Sv. This compares with the overall average of the effective dose equivalent from natural radiation of almost 1900 mu Sv in a year. The distribution of exposures to the short-lived daughters of 222Rn is markedly skew and indicates that some dwellings support concentrations of these daughters leading to exposures in excess of 1 WLM in a year. The areas of the U.K. in which exposures above this level are most likely to occur are regions with enhanced uranium mineralisation. These areas are sparsely populated and high exposures here do not significantly affect the overall average exposure of the population to radon daughters. An intensive survey of radon and radon daughters concentrations in one predominantly igneous region is reported. The average exposure for the 250 dwellings in this region surveyed so far was estimated to be 1.3 WLM in a year, a factor of 8 greater than the national value. About 5% of the homes exceed 5 WLM in a year. Measurements of equilibrium factor indicate that plate-out contributes to the removal of radon daughters from room air. In general, the equilibrium factor measured indicates an unattached fraction of 218Po of less than 10%.

Air↗