5,120 research outputs found
Mitigation of Radiation Induced Pulmonary Vascular Injury by Delayed Treatment with Captopril
Background and Objective: A single dose of 10 Gy radiation to the thorax of rats results in decreased total lung angiotensin-converting enzyme (ACE) activity, pulmonary artery distensibility and distal vascular density while increasing pulmonary vascular resistance (PVR) at 2 months post-exposure. In this study, we evaluate the potential of a renin-angiotensin system (RAS) modulator, the ACE inhibitor captopril, to mitigate this pulmonary vascular damage.
Methods: Rats exposed to 10 Gy thorax only irradiation and age-matched controls were studied 2 months after exposure, during the development of radiation pneumonitis. Rats were treated, either immediately or 2 weeks after radiation exposure, with two doses of the ACE inhibitor, captopril, dissolved in their drinking water. To determine pulmonary vascular responses, we measured pulmonary haemodynamics, lung ACE activity, pulmonary arterial distensibility and peripheral vessel density.
Results: Captopril, given at a vasoactive, but not a lower dose, mitigated radiation-induced pulmonary vascular injury. More importantly, these beneficial effects were observed even if drug therapy was delayed for up to 2 weeks after exposure.
Conclusions: Captopril resulted in a reduction in pulmonary vascular injury that supports its use as a radiomitigator after an unexpected radiological event such as a nuclear accident
New Records of Hyperiidea (Crustacea: Amphipoda) from the North Central Gulf of Mexico
Records of 54 species of amphipods of the suborder Hyperiidea from the Gulf of Mexico are presented. Forty-seven species are recorded from the Gulf for the first time. Previous records of occurrence in the Gulf of Mexico, Caribbean Sea, and associated North Atlantic waters are provided for each species
New Records of Hyperiidea (Crustacea: Amphipoda) from the North Central Gulf of Mexico
Records of 54 species of amphipods of the suborder Hyperiidea from the Gulf of Mexico are presented. Forty-seven species are recorded from the Gulf for the first time. Previous records of occurrence in the Gulf of Mexico, Caribbean Sea, and associated North Atlantic waters are provided for each species
Vascular Injury After Whole Thoracic X-Ray Irradiation in the Rat
Purpose To study vascular injury after whole thoracic irradiation with single sublethal doses of X-rays in the rat and to develop markers that might predict the severity of injury. Methods and Materials Rats that received 5- or 10-Gy thorax-only irradiation and age-matched controls were studied at 3 days, 2 weeks, and 1, 2, 5, and 12 months. Several pulmonary vascular parameters were evaluated, including hemodynamics, vessel density, total lung angiotensin-converting enzyme activity, and right ventricular hypertrophy. Results By 1 month, the rats in the 10-Gy group had pulmonary vascular dropout, right ventricular hypertrophy, increased pulmonary vascular resistance, increased dry lung weights, and decreases in total lung angiotensin-converting enzyme activity, as well as pulmonary artery distensibility. In contrast, irradiation with 5 Gy resulted in only a modest increase in right ventricular weight and a reduction in lung angiotensin-converting enzyme activity. Conclusion In a previous investigation using the same model, we observed that recovery from radiation-induced attenuation of pulmonary vascular reactivity occurred. In the present study, we report that deterioration results in several vascular parameters for ≤1 year after 10 Gy, suggesting sustained remodeling of the pulmonary vasculature. Our data support clinically relevant injuries that appear in a time- and dose-related manner after exposure to relatively low radiation doses
Cost of survivorship care and adherence to screening-aligning the priorities of health care systems and survivors.
Childhood cancer survivors (CCS) experience significant morbidity due to treatment- related late effects and benefit from late-effects surveillance. Adherence to screening recommendations is suboptimal. Survivorship care programs often struggle with resource limitations and may benefit from understanding institution-level financial outcomes associated with patient adherence to justify programmatic development and growth. The purpose of this study is to examine how CCS adherence to screening recommendations relates to the cost of care, insurance status, and institution-level financial outcomes. A retrospective chart review of 286 patients, followed in a structured survivorship program, assessed adherence to the Children\u27s Oncology Group follow-up guidelines by comparing recommended versus performed screening procedures for each patient. Procedure cost estimates were based on insurance status. Institutional profit margins and profit opportunity loss were calculated. Bivariate statistics tested adherent versus nonadherent subgroup differences on cost variables. A generalized linear model predicted the likelihood of adherence based on cost of recommended procedures, controlling for age, gender, race, and insurance. Adherence to recommended surveillance procedures was 50.2%. Nonadherence was associated with higher costs of recommended screening procedures compared to the adherent group estimates (1,211.44). Failure to perform the recommended tests resulted in no difference in reimbursement to the health system between groups (1,211.08). For the nonadherent group, this represented 311,850 in lost profit opportunity due to nonadherence in this subgroup. In the final model, nonadherence was related to higher cost of recommended procedures (p \u3c .0001), older age at visit (p = .04), Black race (p = .02), and government-sponsored insurance (p = .03). Understanding institutional financial outcomes related to patient adherence may help inform survivorship care programs and resource allocation. Potential financial burden to patients associated with complex care recommendations is also warranted
The Impact of Community Size, Community Climate, and Victimization on the Physical and Mental Health of SGM Youth
Paceley MS, Fish JN, Thomas MMC, Goffnett J. The Impact of Community Size, Community Climate, and Victimization on the Physical and Mental Health of SGM Youth. Youth & Society. 2020;52(3):427-448. Copyright © 2020, © SAGE Publications. doi:10.1177/0044118X19856141Sexual and gender minority (SGM) youth experience high rates of victimization leading to health disparities. Community size and community climate are associated with health outcomes among SGM youth; however, we lack studies that include them as covariates alongside victimization to understand their collective impact on health. This study utilized minority stress theory to understand how community context shapes experiences of victimization and health among SGM youth. SGM youth in one Midwestern U.S. state completed an online survey (n = 201) with measures of physical health, mental health, community context, and victimization. Data were analyzed via multiple regression using a path analysis framework. Results indicate that perceived climate was associated with mental, but not physical, health; Community size was unrelated to health outcomes. Victimization mediated the association between community climate and mental health. Findings are discussed in light of current literature and implications for research and practice are shared
On the Doppler effect for light from orbiting sources in Kerr-type metrics
A formula is derived for the combined motional and gravitational Doppler
effect in general stationary axisymmetric metrics for a photon emitted parallel
or antiparallel to the assumed circular orbital motion of its source. The same
formula is derived from eikonal approximation and Killing vector approaches to
elucidate connections between observational astronomy and modern Relativity.
The formula yields expected results in the limits of a moving or stationary
source in the exterior Kerr and Schwarzschild metrics and a moving source in
flat space.Comment: Accepted for publication in in Monthly Notices of the Royal
Astronomical Society Main Journal 1.23.15. This version has substantially
shortened and clarified derivations and added content regarding applicability
of the derivation
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