Imaging of pulmonary embolism and t-PA therapy effects using MDCT and liposomal iohexol blood pool agent: preliminary results in a rabbit model.

RATIONALE AND OBJECTIVES: Polyethylene glycol-coated liposomal blood pool contrast agents maintain contrast enhancement over several hours. This study aimed to evaluate (long-term) imaging of pulmonary arteries, comparing conventional iodinated contrast with a liposomal blood pool contrast agent. Also, visualization of the (real-time) therapeutic effects of tissue plasminogen activator (t-PA) on pulmonary embolism (PE) was attempted. MATERIALS AND METHODS: Six rabbits (weight approximately 4 kg) had autologous blood clots injected through the superior vena cava. Imaging was performed using conventional contrast (iohexol, 350 mg I/ml; GE HealthCare, Princeton, NJ) at a dose of 1400 mg I per animal, and after wash-out, animals were imaged using an iodinated liposomal blood pool agent (88 mg I/mL, dose 900 mg I/animal). Subsequently, five animals were injected with 2 mg of t-PA and imaging continued for up to 4(1/2) hours. RESULTS: Both contrast agents identified PE in the pulmonary trunk and main pulmonary arteries in all rabbits. Liposomal blood pool agent yielded uniform enhancement, which remained relatively constant throughout the experiments. Conventional agents exhibited nonuniform opacification and rapid clearance postinjection. Three of six rabbits had mistimed bolus injections, requiring repeat injections. Following t-PA, pulmonary embolus volume (central to segmental) decreased in four of five treated rabbits (range 10-57%, mean 42%). One animal showed no response to t-PA. CONCLUSIONS: Liposomal blood pool agents effectively identified acute PE without need for reinjection. PE resolution following t-PA was quantifiable over several hours. Blood pool agents offer the potential for repeated imaging procedures without need for repeated (nephrotoxic) contrast injections.

Is sexual intimacy among older adults positively associated with mental well-being?

Background. The elderly population aged 60 and above is increasing rapidly throughout the world. The aging process affects physical health of individuals, which in turn affects sexuality and sexual activity. However, many elderly adults continue to engage in one or more forms of sexual activities well into their 70s, 80s, and even in 90s. Despite the widespread stereotypes, misconceptions, and negative attitudes surrounding sexuality in elderly adults, it has been found to be an important aspect of the health of the elderly. However, association between the frequency of sexual activity and mental well being among older adults has not been documented in the literature. ^ Methods. To test the hypotheses that mental well being indicators such as depression, anxiety, and stress were inversely associated with greater frequency of sexual intimacy, a secondary data analysis was conducted using the National Social Life Health and Aging Project (NSHAP) using multivariate logistic regression. The NSHAP was a population-based study that was conducted on a national scale including 1455 men and 1550 women aged 57-85.^ Results. Approximately 1430 (54.1%) of the total population reported being sexually intimate in the past 12 months whereas 1481 (45.9%) participants reported that they did not perform any sexual activity in the past 12 months. In addition, approximately 895(31.1%) participants reported engaging in sexual activity ≥ 2-3 times per month with 665 (78.9%) of these participants reported performing vaginal intercourse only, 14(2.0%) oral sex only, and 89(10.5%) reported performing both vaginal intercourse and oral sex. Controlling for socio-demographic characteristics, frequently (≥2-3 times per month) sexually active participants showed lower odds ratio of depression (OR= 0.60; 95%CI = 0.46, 0.78), anxiety (OR= 0.67; 95% CI= 0.53, 0.86), and stress (OR=0.73; 95% CI = 0.6, 0.88) compared to those who had less frequent sexual activity or who had no sexual activity in the past 12 months.^ Conclusion. Lower levels of depression, anxiety, and stress appear to be associated with greater frequency of sexual activity. Public health interventions should focus on educating elderly adults about their sexual health and how to seek medical help for their sexual problems. Public health professionals should also be educated on how to best assess sexual needs of the elderly adults.^