Improving Salmonella vector with rec mutation to stabilize the DNA cargoes

<p>Abstract</p> <p>Background</p> <p><it>Salmonella </it>has been employed to deliver therapeutic molecules against cancer and infectious diseases. As the carrier for target gene(s), the cargo plasmid should be stable in the bacterial vector. Plasmid recombination has been reduced in <it>E. coli </it>by mutating several genes including the <it>recA</it>, <it>recE</it>, <it>recF </it>and <it>recJ</it>. However, to our knowledge, there have been no published studies of the effect of these or any other genes that play a role in plasmid recombination in <it>Salmonella enterica</it>.</p> <p>Results</p> <p>The effect of <it>recA</it>, <it>recF </it>and <it>recJ </it>deletions on DNA recombination was examined in three serotypes of <it>Salmonella enterica</it>. We found that (1) intraplasmid recombination between direct duplications was RecF-independent in Typhimurium and Paratyphi A, but could be significantly reduced in Typhi by a Δ<it>recA </it>or Δ<it>recF </it>mutation; (2) in all three <it>Salmonella </it>serotypes, both Δ<it>recA </it>and Δ<it>recF </it>mutations reduced intraplasmid recombination when a 1041 bp intervening sequence was present between the duplications; (3) Δ<it>recA </it>and Δ<it>recF </it>mutations resulted in lower frequencies of interplasmid recombination in Typhimurium and Paratyphi A, but not in Typhi; (4) in some cases, a Δ<it>recJ </it>mutation could reduce plasmid recombination but was less effective than Δ<it>recA </it>and Δ<it>recF </it>mutations. We also examined chromosome-related recombination. The frequencies of intrachromosomal recombination and plasmid integration into the chromosome were 2 and 3 logs lower than plasmid recombination frequencies in Rec⁺strains. A Δ<it>recA </it>mutation reduced both intrachromosomal recombination and plasmid integration frequencies.</p> <p>Conclusions</p> <p>The Δ<it>recA </it>and Δ<it>recF </it>mutations can reduce plasmid recombination frequencies in <it>Salmonella enterica</it>, but the effect can vary between serovars. This information will be useful for developing <it>Salmonella </it>delivery vectors able to stably maintain plasmid cargoes for vaccine development and gene therapy.</p

Rationale and design: telepsychology service delivery for depressed elderly veterans

<p>Abstract</p> <p>Background</p> <p>Older adults who live in rural areas experience significant disparities in health status and access to mental health care. "Telepsychology," (also referred to as "telepsychiatry," or "telemental health") represents a potential strategy towards addressing this longstanding problem. Older adults may benefit from telepsychology due to its: (1) utility to address existing problematic access to care for rural residents; (2) capacity to reduce stigma associated with traditional mental health care; and (3) utility to overcome significant age-related problems in ambulation and transportation. Moreover, preliminary evidence indicates that telepsychiatry programs are often less expensive for patients, and reduce travel time, travel costs, and time off from work. Thus, telepsychology may provide a cost-efficient solution to access-to-care problems in rural areas.</p> <p>Methods</p> <p>We describe an ongoing four-year prospective, randomized clinical trial comparing the effectiveness of an empirically supported treatment for major depressive disorder, Behavioral Activation, delivered either via in-home videoconferencing technology ("Telepsychology") or traditional face-to-face services ("Same-Room"). Our hypothesis is that in-homeTelepsychology service delivery will be equally effective as the traditional mode (Same-Room). Two-hundred twenty-four (224) male and female elderly participants will be administered protocol-driven individual Behavioral Activation therapy for depression over an 8-week period; and subjects will be followed for 12-months to ascertain longer-term effects of the treatment on three outcomes domains: (1) clinical outcomes (symptom severity, social functioning); (2) process variables (patient satisfaction, treatment credibility, attendance, adherence, dropout); and (3) economic outcomes (cost and resource use).</p> <p>Discussion</p> <p>Results from the proposed study will provide important insight into whether telepsychology service delivery is as effective as the traditional mode of service delivery, defined in terms of clinical, process, and economic outcomes, for elderly patients with depression residing in rural areas without adequate access to mental health services.</p> <p>Trial registration</p> <p>National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov identifier# NCT00324701).</p

An assessment of American Indian women's mammography experiences

<p>Abstract</p> <p>Background</p> <p>Mortality from breast cancer has increased among American Indian/Alaskan Native (AI/AN) women. Despite this alarming reality, AI/AN women have some of the lowest breast cancer screening rates. Only 37% of eligible AI/AN women report a mammogram within the last year and 52% report a mammogram within the last two years compared to 57% and 72% for White women. The experiences and satisfaction surrounding mammography for AI/AN women likely are different from that of women of other racial/ethnic groups, due to cultural differences and limited access to Indian Health Service sponsored mammography units. The overall goals of this study are to identify and understand the mammography experiences and experiential elements that relate to satisfaction or dissatisfaction with mammography services in an AI/AN population and to develop a culturally-tailored AI/AN mammography satisfaction survey.</p> <p>Methods and Design</p> <p>The three project aims that will be used to guide this work are: 1) To compare the mammography experiences and satisfaction with mammography services of Native American/Alaska Native women with that of Non-Hispanic White, Hispanic, and Black women, 2) To develop and validate the psychometric properties of an American Indian Mammography Survey, and 3) To assess variation among AI/AN women's assessments of their mammography experiences and mammography service satisfaction. Evaluations of racial/ethnic differences in mammography patient satisfaction have received little study, particularly among AI/AN women. As such, qualitative study is uniquely suited for an initial examination of their experiences because it will allow for a rich and in-depth identification and exploration of satisfaction elements.</p> <p>Discussion</p> <p>This formative research is an essential step in the development of a validated and culturally tailored AI/AN mammography satisfaction assessment. Results from this project will provide a springboard from which a maximally effective breast cancer screening program to benefit AI/AN population will be developed and tested in an effort to alter the current breast cancer-related morbidity and mortality trajectory among AI/AN women.</p