Accurate myocardial T1 measurements: toward quantification of myocardial blood flow with arterial spin labeling.

In this study, we investigated a method for accurately measuring myocardial T(1) for the quantification of myocardial blood flow (MBF) with arterial spin labeling (ASL). A single-shot gradient-echo (GE)-based ASL sequence with an adiabatic hyperbolic secant inversion recovery pulse was modified to acquire a pair of myocardial T(1)'s within a breath-hold. A multivariable regression algorithm that accounted for the magnetization saturation effects was developed to calculate T(1). The MBF was then determined with a well-developed model. The accuracy of our T(1) calculation was first evaluated in a phantom, and then in six dogs for the MBF calculation, with (N = 4) and without (N = 2) coronary artery stenosis. In the phantom study, the accuracy of T(1) measured with a slice-selective inversion prepared pulse was within 2.5% of error. In healthy dogs, the MBF increased 2-5 times during vasodilation. In contrast, regional differences of MBF were well visualized in the stenotic dogs during vasodilation (perfusion reserve of 2.75 +/- 0.83 in normal myocardium, and 1.46 +/- 0.75 in the stenotic area). A correlation analysis revealed a close agreement in MBF between the ASL and microsphere (MS) in both healthy and stenotic dogs. In summary, the modified ASL technique and T(1) regression algorithm proposed here provide an accurate measurement of myocardial T(1) and demonstrate potential for reliably assessing MBF at steady state.     

Depression and bone mineral density: is there a relationship in elderly Asian men? Results from Mr. Os (Hong Kong)

Previous epidemiological study has suggested that depression might be associated with low bone mass in Caucasian women. This has not been studied in Asian men. Mr. Os (Hong Kong) is the first, large, cohort study on osteoporosis in Asian men, and the current analysis deals with the association between depression and bone mass in this group. Data from the baseline examination of Mr. Os (Hong Kong) were used. Two thousand Hong Kong men aged 65 to 92 years were recruited from the community. Depression was diagnosed by face-to-face interview, using a validated Chinese version of the Geriatric Depression Scale (GDS), with depression being defined as a cut-off score of 8 or more. Bone mineral density (BMD) of the lumbar spine, total hip and total body was measured by dual X-ray densitometry (DEXA) using the Hologic QDR-4500 W densitometer. Multiple regression was used to compare BMD in depressed and non-depressed subjects, controlling for confounding variables. In the study sample 8.5% of men were found to be depressed, and the BMD at the total hip in these subjects was 2.1% lower than in non-depressed subjects (95% CI –0.13 to –4.1), after adjustment for age, body weight, medical history, alcohol consumption, cigarette smoking, calcium intake, physical activity and antidepressant use. Depression was associated with a 1.4-fold (95% CI 1.00 to 2.08) relative risk (RR) of being diagnosed with a T-score equal to or less than –1.0 (low bone mass). We conclude that depression is associated with lower BMD; however, to determine whether depression causes lower BMD or vice versa, we will need to await findings from future prospective studies.Abstract presented at the 25th Annual Meeting of the American Society for Bone and Mineral Research on 21 September 2003, Minnesota, Minneapolis, USA     

Trends in Tuberculosis Reported From the Appalachian Region: United States, 1993-2005

ABSTRACT:  Context: Appalachia has been characterized by its poverty, a factor associated with tuberculosis, yet little is known about the disease in this region. Purpose: To determine whether Appalachian tuberculosis risk factors, trends, and rates differ from the rest of the United States. Methods: Analysis of tuberculosis cases reported to the Centers for Disease Control and Prevention's National Tuberculosis Surveillance System (NTSS) within the 50 states and the District of Columbia from 1993 through 2005. Results: The 2005 rate of tuberculosis in rural Appalachia was 2.1/100,000, compared to 2.7/100,000 in urban Appalachia. Urban non-Appalachia had a 2005 tuberculosis rate of 5.4/100,000. Over the 13-year period, tuberculosis rates fell in Appalachia at an annual rate of 7.8%. In one age group (15- to 24-year-olds) the rates increased at an annual rate of 2.8%. Foreign-born Hispanics were the largest racial/ethnic group in this age group. When private providers gave exclusive care for tuberculosis disease, Appalachians were less likely to complete therapy in a timely manner when compared to non-Appalachians (OR 0.6, 95% CI 0.5-0.7). Conclusions: Tuberculosis rates and trends are similar in urban and rural Appalachia. It is crucial for public health officials in Appalachia to address the escalating TB rate among 15- to 24-year-olds by focusing prevention efforts on the growing numbers of foreign-born cases. Due to the increased risk of treatment failure among Appalachians who do not seek care from the health department, public health authorities must ensure completion of treatment for patients who seek private providers.     

Moderators of the intention-behaviour and perceived behavioural control-behaviour relationships for leisure-time physical activity

Background  

Intention is a key determinant of action. However, there is a gap between intention and behavioural performance that remains to be explained. Therefore, the aim of this study was to identify moderators of the intention-behaviour and perceived behavioural control (PBC)- behaviour relationships for leisure-time physical activity.