WinSAAM: application and explanation of use.
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Biomedical subjects
Publications and source records attributed to Raymond C Boston.
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Over the last 50 years, complex, dynamic, compartmental models have been used to describe and to make predictions on a host of pharmacokinetic, metabolic, and biological systems. Sophisticated modeling software is required to fit data to such models and to make predictions using these compartmental models. WinSAAM is one such modeling program. The purpose the current report is to describe the features of WinSAAM that make this program suited for modeling all manner of biological systems. We highlight new features, especially those that are unique to WinSAAM, and illustrate with examples how WinSAAM is used to construct models of metabolic systems, to simulate the effects of experiments on systems, and to fit models to data.
BACKGROUND: Men are believed to have more visceral adipose tissue (VAT) than women have, but studies in African Americans that measured VAT from a single computed tomography (CT) slice found no sex difference. OBJECTIVE: We used a serial-slice CT scan to investigate whether there is a sex difference in VAT volume among African Americans. DESIGN: Single-slice CT measurements of VAT area at lumbar spine L2-3 and L4-5 levels were taken in 110 African Americans (44 men, 66 women). In 59 subjects (24 men, 35 women), VAT volume was also measured with contiguous CT slices from the diaphragm to the iliac crest. Fat mass was determined by dual-energy X-ray absorptiometry. RESULTS: Men and women had similar ages (x +/- SD: 36.1 +/- 7.8 and 35.6 +/- 7.8 y, respectively) and body mass indexes in kg/m(2) (29.5 +/- 6.9 and 32.0 +/- 8.9). The percentage of body fat was lower (P < 0.0001) in men (21.8 +/- 7.3%) than in women (37.4 +/- 7.9%). The VAT volume was greater (P = 0.01) in men (1443 +/- 931 cm(3)) than in women (940 +/- 821 cm(3)). There was no sex difference in unadjusted VAT area at L2-3 (men, 88.6 +/- 63.5 cm(2); women, 57.2 +/- 45.4 cm(2)) or L4-5 (men, 65.6 +/- 53.3 cm(2); women, 55.0 +/- 38.3 cm(2)). After adjustment for percentage of body fat or fat mass, men had larger VAT area at both levels (P < 0.01). After adjustment for body mass index, the sex difference in VAT area was detectable at L2-3 (P < 0.001) but not at L4-5 (P = 0.22). CONCLUSIONS: VAT volume is greater in men than in women. Detection of sex differences in VAT area among African Americans on single-slice CT requires adjustment for body fat content. At L2-3, adjustment for body mass index alone is adequate to detect sex differences in VAT.
PURPOSE: To evaluate the ability of Gadomer-17 to depict perfusion defects in a closed-chest swine model of single-vessel coronary artery disease. MATERIALS AND METHODS: Twelve pigs underwent closed-chest placement of a flow reducer for 70%-90% luminal stenosis in the proximal left anterior coronary artery. Magnetic resonance (MR) perfusion imaging with Gadomer-17 and gadopentetate dimeglumine, microsphere blood flow (MBF) testing, and technetium 99m ((99m)Tc) 2 methoxyisobutylisonitrile (MIBI) single photon emission computed tomography (SPECT) were performed during dipyridamole vasodilation. Comparisons of percentage signal intensity (SI) increase (PSIC) in remote and ischemic myocardium were made with repeated measurements analysis of variance after injection of both tracers. RESULTS: Perfusion defects and reduced PSIC in the anterior ischemic versus the inferior remote myocardium could be identified after injection of both Gadomer-17 (PSIC, 66% +/- 30 [mean +/- SD] vs 100% +/- 32, respectively; P <.001) and gadopentetate dimeglumine (PSIC, 49% +/- 31 vs 81% +/- 43, respectively; P <.005). The size of perfusion defect depicted with both tracers was highly correlated with defect size at (99m)Tc MIBI SPECT (r = 0.69, P <.05 for Gadomer-17 and r = 0.60, P =.05 for gadopentetate dimeglumine) and with areas of reduced MBF (r = 0.70, P <.05 for Gadomer-17 and r = 0.80, P <.05 for gadopentetate dimeglumine). PSIC also correlated with MBF (r = 0.89, P <.001 for Gadomer-17 and r = 0.75, P <.001 for gadopentetate dimeglumine). Gadomer-17 allowed differentiation of ischemic from nonischemic myocardium, as demonstrated by reduced PSIC (PSIC, 48% +/- 38 vs 72% +/- 31, respectively; P <.001) until 20 minutes after contrast material injection. In contrast, differentiation of ischemic from nonischemic myocardium was possible only until 55 seconds after injection of gadopentetate dimeglumine (PSIC, 36% +/- 24 vs 56% +/- 27, respectively; P <.005) but not at any time point thereafter. CONCLUSION: With the study conditions, Gadomer-17 provided more prolonged differentiation of ischemic from remote myocardium than that with gadopentetate dimeglumine.