Narrow-pore flow behavior of blood cells in cardioplegic suspension

Flow-driven competition between two capsules passing through a narrow pore

By incorporating a distance function into the finite element simulation, we investigate the flow-driven competition between two soft capsules passing through a narrow pore, employing the arbitrary Lagrangian-Eulerian formulation to satisfy the boundary conditions for fluid flow and capsule deformation. In our simulations, the motion and deformation of the capsules can be described in an intuitive manner, and the order in which capsules of different sizes pass through a pore can be clearly determined. Meanwhile, when the capsules are near the narrow pore, the change of the flow field is also very interesting and can be expressed intuitively. It is shown that, driven by the Poiseuille flow, the larger capsule has a stronger tendency to pass through the pore than the small one, which can be attributed to the greater resistance and the volume advantage of the larger capsule. In addition, we demonstrate that this tendency can be reversed by changing the inlet velocity and setting the initial position of the smaller capsule closer to the axis of the pore. And as long as the large one passes through first, the small one will offset the axis to the same orientation as the initial, while the large one always moves along the axis.

Factors associated with accelerated atherosclerosis in HIV-1-infected persons treated with protease inhibitors

Recent evidence suggests that as a group protease inhibitors (PIs) may accelerate certain factors associated with atherosclerosis. The objective of this study was to evaluate the effect of individual PIs (indinavir, lopinavir, nelfinavir, ritonavir, and saquinavir) on certain factors associated with atherosclerosis. Persons who took saquinavir and/or ritonavir were compared with those on other PIs. Between May 2000 and July 2001, the lipid profiles, C-reactive protein (CRP) levels, coronary artery calcium (CAC) scores, and blood cell morphologic parameters were measured in 98 black adult participants aged 25 to 45 years with HIV-1 infection in Baltimore, Maryland. Among these 98, there were 55 (56.1%) taking PIs. Students' t-test and chi2 test were used to detect the between-group differences. Study participants in both the PI and non-PI groups were similar in age, sex, body mass index, blood pressure, red and white blood cell counts, time since HIV diagnosis, and duration on anti-retroviral therapy. Compared with those who took non-PI regimens, those who took indinavir, nelfinavir, or saquinavir had significantly higher levels of mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH). Those taking any PI had significantly higher total cholesterol and low-density lipoprotein. Those taking nelfinavir, ritonavir, or saquinavir were more likely to have a higher CAC score (>5) than those on non-PI regimens. There were no differences in the lipid profiles, MCV, MCH, CRP, and CAC between those taking saquinavir and/or ritonavir and those taking other PIs. Overall, the changes noted might lead to anticipation of clinical changes linked to accelerated atherosclerosis in patients on PIs.

Coronary artery calcification, atherogenic lipid changes, and increased erythrocyte volume in black injection drug users infected with human immunodeficiency virus-1 treated with protease inhibitors

BACKGROUND

Protease inhibitors (PIs) may be associated with accelerated atherosclerosis in individuals infected with human immunodeficiency virus (HIV). We assessed the effects of HIV PIs on subclinical atherosclerosis.

METHODS

The lipid profiles, C-reactive protein (CRP) levels, coronary artery calcification (CAC) scores, and blood cell morphologic changes were quantified in 98 black adult participants, aged 25 to 45 years, with HIV-1 infection in Baltimore, Md. Fifty-five participants (56.1%) were taking PIs; 43 participants (43.9%) were not. The Student t and chi(2) tests were used as a means of detecting the between-group differences.

RESULTS

Participants in both the PI and non-PI groups were similar in age, sex, body mass index, blood pressure, heart rate, and red and white blood cell counts. Compared with the non-PI group, the PI group had significantly higher serum total cholesterol (4.8 +/- 1.0 vs 3.8 +/- 0.7 mmol/L, P <.001) and LDL cholesterol (2.9 +/- 0.8 vs 2.1 +/- 0.7 mmol/L, P <.001) levels and red blood cell mean corpuscular volume (92.2 +/- 9.3 vs 86.8 +/- 7.2 microm3, P =.048). The CAC scores in the PI group were also higher than those in the non-PI group (11.0 +/- 28.6 [n = 43] vs 1.7 +/- 5.8, P =.043). CAC scores were marginally associated with log-transformed duration of the PI therapy (P =.055). Serum CRP levels remained unchanged (5.5 +/- 13.6 mg/L [n = 45] vs 3.9 +/- 5.5 mg/L, P =.467). Serum total cholesterol level, LDL cholesterol level, red blood cell mean corpuscular volume, and CAC scores were indicated by means of regression analyses to be associated with log-transformed duration of the PI therapy.

CONCLUSIONS

The use of PIs is associated with coronary artery calcification, atherogenic lipid changes, and increased erythrocyte volume in individuals infected with HIV-1.