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Biomedical subjects

L S Lloyd

Publications and source records attributed to L S Lloyd.

11 recordsLinked to original sources
PubMed1996

Organizing Asian Pacific Islanders in an urban community to reduce HIV risk: a case study.

We present a case study of community organization efforts within the Asian Pacific Islander communities of San Diego County to reduce the risk of HIV transmission. We utilized a five-phase process to implement the strategies of locality development, social planning, and social action: community analysis, program design and initiation, program implementation, program maintenance and consolidation, and program reassessment. An evaluation of the process indicates that there were increases over time in the project's activities as well as in the levels of interagency connectedness. This is one of the few reported efforts to organize Asian Pacific Islander groups to address HIV transmission. Key elements that led to the successful organization of the original project into a tax-exempt nonprofit entity (the Asian Pacific Islander Community AIDS Project) were emphasis on community ownership, reliance on group consensus, use of "gatekeepers" to access communities, simultaneous multilevel programming, and service to the community as a "coordinating" entity.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Community participation in dengue prevention and control: a survey of knowledge, attitudes, and practice in Trinidad and Tobago.

The priorities of public health planners are often at variance with the community's own environmental sanitation priorities and perspectives. Public opinion about individual, collective, and governmental responsibilities in addressing these issues and priorities is of particular importance when designing community-based programs. In a study conducted in Trinidad and Tobago on knowledge, attitudes, and practice regarding dengue, its prevention and control, a high level of awareness about dengue and its etiology was evident, but there was poor understanding of the symptoms and hence little concern about the health risks associated with it. The most important household pest problem identified by the respondents was related to mosquito nuisance, particularly from night-biting mosquitoes. Rodents were also a major concern perceived as being responsible for economic losses, ruined food, and a health hazard. Unreliable water supply, a factor associated with Aedes aegypti abundance, was an environmental sanitation issue of major importance to householders in rural areas. No correlation was found between knowledge of dengue and levels of Ae. aegypti abundance as measured by larval surveys of the respondents' premises. The study gave a clear indication of the need for broad-based environmental sanitation strategies when planning community-based vector control initiatives for the prevention and control of dengue in Trinidad and Tobago.

Aedes↗
PubMed1994

Vector control at the household level: an analysis of its impact on women.

The home is the setting where many vector-borne diseases are transmitted. Strategies for their control consequently have to involve the active participation of householders. In this paper we propose that low rates of participation in control activities frequently are related to the negative impact they have on women's power and authority within the domestic domain. This can arise from intrusion into domestic space by male vector control personnel, reorganization of the domestic environment as part of control activities, and promulgation of the idea that disease originates from within the home. In addition, women may need to make significant investments of both time and money in order to carry out the recommended control measures. Very little is known about the impact of vector control measures on women. This subject will assume increasing relevance as planners seek to involve householders, rather than the personnel of vertically-organized control programmes, in the implementation of vector control measures.

Animals↗
PubMed1994

The design of a community-based health education intervention for the control of Aedes aegypti.

This report describes the process used to develop locally appropriate educational materials and to implement the education component of a community-based Aedes aegypti control program in Merida, Yucatan, Mexico. The process is broken into five stages: formative research, developing recommendations for behavior change, development of educational messages, development and production of educational materials, and distribution of the materials. Appropriate terminology and taxonomies for dengue were obtained from open in-depth interviews; baseline data from a knowledge, beliefs, and practices questionnaire served to confirm this information. A larval survey of house lots was carried out to identify the Ae. aegypti larval production sites found on individual house lots. This enabled the program to target the most important larval habitats. Community groups were organized to work on the development of messages and production of the educational materials to be used. The education intervention was successful in stimulating changes in both knowledge and behavior, which were measured in the evaluations of the intervention. To be successful, community-based strategies must be flexible and adapted to the local setting because of ecologic, cultural, and social differences between localities.

Aedes↗
PubMed1992

Results of a community-based Aedes aegypti control program in Merida, Yucatan, Mexico.

This report describes the results of a community-based Aedes aegypti control program in Merida, Yucatan, Mexico. Baseline surveys concerning knowledge, beliefs, and practices of 577 women and a larval survey of 616 house lots were carried out in October 1989. Following development of a public health communication intervention from this data, the program was implemented in six communities. Evaluation used an untreated control group design with pretest and two post-tests, one at completion and one six months later. Significant changes in knowledge and behavior were seen in the treatment group in both post-tests. Women in the intervention group were able to identify the Ae. aegypti mosquito, the larval production sites of the mosquito, and appropriate control methods. A behavior change proxy was measured by examining changes in the Breteau (number of positive containers/100 houses surveyed) and container indices. The Breteau index remained the same in the intervention group while it increased significantly in the comparison group. Changes were also seen with respect to individual containers. This project demonstrated that a community-based communication program aimed at larval production site elimination or control can be effective in changing behavior and reducing larval production sites.

Adult↗
PubMed1992

Variation in Aedes aegypti larval indices over a one year period in a neighborhood of Mérida, Yucatán, México.

Surveys for Aedes aegypti larvae were conducted to provide an estimate of the magnitude and timing of seasonal variations in larval indices in one colonia in Mérida, Yucatán, México, and to assess how the proportion of disposable and non-disposable containers as larval production sites varies. Breteau indices exceeded 200 during the months of July and August, and disposable containers were important year-round larval production sites.

Aedes↗
PubMed1983

Comparison of DNA scission and cytotoxicity produced by Adriamycin and 5-iminodaunorubicin in human colon carcinoma cells.

The quinone-modified anthracycline, 5-iminodaunorubicin, which does not spontaneously generate free radicals, was compared to Adriamycin on the basis of DNA-protein crosslink-associated single-strand breakage, cell lethality, and the pharmacokinetics of drug uptake and efflux in human colon carcinoma cells in culture. At equivalent cytocidal concentrations, 5-iminodaunorubicin produced more single-strand breakage of DNA than Adriamycin after a 2-hr treatment interval, but the DNA scission produced by 5-iminodaunorubicin rapidly disappeared after drug removal. The kinetics of DNA breakage correlated with the rapid rates of uptake and efflux of 5-iminodaunorubicin in comparison to Adriamycin. These data emphasize the importance of the cellular pharmacokinetics of anthracyclines in relation to their cytocidal and DNA damaging properties. Moreover, the induction of equivalent single-strand breakage of DNA by similar intracellular concentrations of both drugs suggests that the free radical properties of Adriamycin are not involved in DNA scission.

Cell Survival↗
PubMed1982

Effects of 8-azaadenosine and formycin on cell lethality and the synthesis and methylation of nucleic acids in human colon carcinoma cells in culture.

The cytocidal and biochemical effects of formycin and 8-azaadenosine in the presence and absence of the adenosine deaminase inhibitor, 2'-deoxycoformycin, were studied in human colon carcinoma (HT-29) cells in culture. Logarithmically growing cells were unaffected by 24-hr exposure to either 10(-6) M formycin or 8-azaadenosine, but 1 to 1.4 log reductions in colony formation were produced by 10(-5) M of each analog. In the presence of 10(-6) M 2'-deoxycoformycin, a 3- and 30-fold potentiation of the cytocidal activity of 8-azaadenosine and formycin, respectively, was produced. Inhibition of DNA synthesis but not RNA synthesis by 8-azaadenosine paralleled its cytocidal activity; however, neither variable correlated closely with the cytotoxic effects of formycin. In addition, the methylation of nuclear RNA was unaffected by both drugs while the methylation of 5-methyl-deoxy-cytidine in DNA was inhibited to a lesser extent than DNA synthesis. Measurements of the incorporation of [3H]formycin and [3H]8-azaadenosine into nuclear RNA and DNA in the presence and absence of 2'-deoxycorformycin indicated that formycin substitution in RNA and DNA was enhanced 10- and 20-fold, respectively, while [3H]8-azaadenosine incorporation into both nucleic acids was increased 6- to 7-fold. These results suggest that the incorporation of formycin into nucleic acids, particularly DNA, correlates closely with its lethal effect on cell viability. On the other hand, the cytocidal activity of 8-azaadenosine more clearly parallels its inhibitory effect on DNA synthesis rather than its substitution into nucleic acids.

Adenosine↗
PubMed1982

Association of cell lethality with incorporation of 5-fluorouracil and 5-fluorouridine into nuclear RNA in human colon carcinoma cells in culture.

The cytokinetic and biochemical effects of 5-fluorouracil and 5-fluorouridine were examined in a human colon carcinoma cell line (HT-29) in culture. Logarithmically growing cells were approximately 100 times more sensitive to the lethal effects of 5-fluorouridine than 5-fluorouracil as measured by colony formation in soft agar medium. A 2-hr exposure of cells to 10(-3) M 5-fluorouracil or 10(-5) M 5-fluorouridine produced a 2-log reduction in colony formation, a 31--33% inhibition of [14C]deoxyguanosine incorporation into DNA, and 30--40% inhibition of [3H]adenosine incorporation into total RNA. Increasing the duration of drug exposure to 24 hr produced a proportional reduction in the drug concentration required to produce similar biochemical and cytocidal effects. However, cell lethality produced by either drug did not correlate quantitatively with inhibition of DNA or RNA synthesis. Examination of nuclear rRNA and 4 S RNA synthesis by agarose gel electrophoresis following 2-hr and 24-hr exposure to 5-fluorouracil or 5-fluorouridine indicated that processing of rRNA was not impaired, rRNA synthesis was inhibited by 10--40%, and 4 S RNA synthesis was unaffected. In contrast to these results, measurements of the incorporation fo [3H]5-fluorouracil or [3H]5-fluorouridine into nuclear RNA showed that a significant correspondence existed between the amount of drug incorporated into nuclear RNA and cell lethality. These results indicate that the primary determinant of cell lethality in HT-29 cells is the degree of fluoropyrimidine substitution in nuclear RNA and not inhibition of either DNA or RNA synthesis.

Cell Nucleus↗