Ceria-based solid catalysts for organic chemistry

Ceria has been the subject of thorough investigations, mainly because of its use as an active component of catalytic converters for the treatment of exhaust gases. However, ceria-based catalysts have also been developed for different applications in organic chemistry. The redox and acid-base properties of ceria, either alone or in the presence of transition metals, are important parameters that allow to activate complex organic molecules and to selectively orient their transformation. Pure ceria is used in several organic reactions, such as the dehydration of alcohols, the alkylation of aromatic compounds, ketone formation, and aldolization, and in redox reactions. Ceria-supported metal catalysts allow the hydrogenation of many unsaturated compounds. They can also be used for coupling or ring-opening reactions. Cerium atoms can be added as dopants to catalytic system or impregnated onto zeolites and mesoporous catalyst materials to improve their performances. This Review demonstrates that the exceptional surface (and sometimes bulk) properties of ceria make cerium-based catalysts very effective for a broad range of organic reactions.

Markers of inflammation, coagulation, and renal function are elevated in adults with HIV infection

BACKGROUND

Human immunodeficiency virus (HIV) replication and immune activation may increase inflammation and coagulation biomarkers. Limited data exist comparing such biomarkers in persons with and without HIV infection.

METHODS

For persons 45-76 years of age, levels of high-sensitivity C-reactive protein (hsCRP), interleukin (IL)-6, D-dimer, and cystatin C were compared in 494 HIV-infected individuals in the Strategies for Management of Anti-Retroviral Therapy (SMART) study and 5386 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) study. For persons 33-44 years of age, hsCRP and IL-6 levels were compared in 287 participants in the SMART study and 3231 participants in the Coronary Artery Development in Young Adults (CARDIA) study.

RESULTS

hsCRP and IL-6 levels were 55% (P < . 001) and 62 (P < . 001) higher among HIV-infected participants than among CARDIA study participants. Compared with levels noted in MESA study participants, hsCRP, IL-6, D-dimer, and cystatin C levels were 50%, 152%, 94%, and 27% higher, respectively (P < . 001, for each), among HIV-infected participants. HIV-infected participants receiving antiretroviral therapy who had HIV RNA levels 400 copies/mL had levels higher (by 21% to 60%) (P < . 001) than those in the general population, for all biomarkers.

CONCLUSIONS

hsCRP, IL-6, D-dimer, and cystatin C levels are elevated in persons with HIV infection and remain so even after HIV RNA levels are suppressed with antiretroviral therapy. Additional research is needed on the pathophysiology of HIV-induced activation of inflammatory and coagulation pathways, to guide potential interventions.

High-density lipoprotein particles and markers of inflammation and thrombotic activity in patients with untreated HIV infection

BACKGROUND

Untreated human immunodeficiency virus (HIV) infection is associated with changes in blood lipids, inflammation, thrombotic activity, and increased risk for cardiovascular disease.

METHODS

We studied high-density lipoprotein particle (HDLp) concentrations and inflammatory (high-sensitivity C-reactive protein [hsCRP] and interleukin [IL] 6), endothelial activation (E-selectin and soluble intercellular adhesion molecule-1 [sICAM-1]), and thrombotic (fibrinogen and D-dimer) biomarkers in a group of 32 untreated HIV-infected and 29 uninfected persons. Differences in the levels of blood lipids and biomarkers by HIV status were examined before and after adjustment for age, sex, race/ethnicity, smoking status, body mass index, and the presence of hepatitis C.

RESULTS

HIV-infected participants, compared with uninfected participants, had lower HDL cholesterol (HDLc) levels (-26%) and HDLp numbers (-21%), with reductions in large (-50%) and small (-20%) HDLp, specifically (P < or = .01 for all). A trend was present for higher total cholesterol (P = .15 and triglyceride levels (P = .11) among individuals with HIV infection. Levels of IL-6, sICAM-1, and D-dimer were 65%-70% higher in HIV-infected participants (P < or = .02 for all). Covariate adjustment did not diminish these associations. For HIV-infected participants, total and small HDLp (respectively) tended to correlate inversely with levels of IL-6 (P = .08 and P = .02), sICAM-1 (P < .01 for both) and D-dimer (P = .03 and p < .01).

CONCLUSIONS

Persons with untreated HIV infection have lower HDLp (primarily large and small HDLp) and higher IL-6, sICAM-1, and D-dimer levels, and the relationship of these markers to HIV-mediated atherosclerotic risk requires further study.

Structural and functional vascular alterations and incident hypertension in normotensive adults: the Multi-Ethnic Study of Atherosclerosis

Vascular abnormalities may exist before clinical hypertension. Using Poisson regression, the authors studied the association of coronary artery calcium (CAC), common carotid intima-media thickness (CIMT), aortic distensibility, and large and small arterial elasticity with incident hypertension among 2,512 normotensive US adults free of cardiovascular disease. Incidence rate ratios for incident hypertension (blood pressure > or =140/90 mm Hg or new antihypertensive medication) were calculated. Increased CAC was associated with incident hypertension in demographics-adjusted models (incidence rate ratio (IRR) = 1.35, 95% confidence interval (CI): 1.04, 1.75; IRR = 1.35, 95% CI: 1.02, 1.78; and IRR = 1.59, 95% CI: 1.12, 2.25 for CAC scores of 30-99, 100-399, and > or =400, respectively) but was attenuated after further adjustment. Increased common CIMT was associated with incident hypertension (IRR = 1.77, 95% CI: 1.28, 2.46 for quintile 4; IRR = 1.80, 95% CI: 1.28, 2.53 for quintile 5). Participants with the lowest, compared with the highest, aortic distensibility had an increased risk of hypertension (IRR = 1.75, 95% CI: 1.10, 2.79), as did those with the lowest large arterial elasticity (IRR = 1.49, 95% CI: 1.11, 1.99). Lower small arterial elasticity was incrementally associated with incident hypertension starting at quintile 2 (IRR = 2.01, 95% CI: 1.39, 2.91; IRR = 2.47, 95% CI: 1.71, 3.57; IRR = 2.73, 95% CI: 1.88, 3.95; and IRR = 2.85, 95% CI: 1.95, 4.16). Structural and functional vascular abnormalities are independent predictors of incident hypertension. These findings are important for understanding the pathogenesis of hypertension.

The E3 ubiquitin ligase specificity subunit ASB2beta is a novel regulator of muscle differentiation that targets filamin B to proteasomal degradation

Ubiquitin-mediated protein degradation is the main mechanism for controlled proteolysis, which is crucial for muscle development and maintenance. The ankyrin repeat-containing protein with a suppressor of cytokine signaling box 2 gene (ASB2) encodes the specificity subunit of an E3 ubiquitin ligase complex involved in differentiation of hematopoietic cells. Here, we provide the first evidence that a novel ASB2 isoform, ASB2beta, is important for muscle differentiation. ASB2beta is expressed in muscle cells during embryogenesis and in adult tissues. ASB2beta is part of an active E3 ubiquitin ligase complex and targets the actin-binding protein filamin B (FLNb) for proteasomal degradation. Thus, ASB2beta regulates FLNb functions by controlling its degradation. Knockdown of endogenous ASB2beta by shRNAs during induced differentiation of C2C12 cells delayed FLNb degradation as well as myoblast fusion and expression of muscle contractile proteins. Finally, knockdown of FLNb in ASB2beta knockdown cells restores myogenic differentiation. Altogether, our results suggest that ASB2beta is involved in muscle differentiation through the targeting of FLNb to destruction by the proteasome.

Determination of the underlying cause of death in three multicenter international HIV clinical trials

PURPOSE

Describe processes and challenges for an Endpoint Review Committee (ERC) in determining and adjudicating underlying causes of death in HIV clinical trials.

METHOD

Three randomized HIV trials (two evaluating interleukin-2 and one treatment interruption) enrolled 11,593 persons from 36 countries during 1999-2008. Three ERC members independently reviewed each death report and supporting source documentation to assign underlying cause of death; differences of opinion were adjudicated.

RESULTS

Of 453 deaths reported through January 14, 2008, underlying causes were as follows: 10% AIDS-defining diseases, 21% non-AIDS malignancies, 9% cardiac diseases, 9% liver disease, 8% non-AIDS-defining infections, 5% suicides, 5% other traumatic events/accidents, 4% drug overdoses/acute intoxications, 11% other causes, and 18% unknown. Major reasons for unknown classification were inadequate clinical information or supporting documentation to determine cause of death. Half (51%) of deaths reviewed by the ERC required follow-up adjudication; consensus was eventually always reached.

CONCLUSION

ERCs can successfully provide blinded, independent, and systematic determinations of underlying cause of death in HIV clinical trials. Committees should include those familiar with AIDS and non-AIDS-defining diseases and have processes for adjudicating differences of opinion. Training for local investigators and procedure manuals should emphasize obtaining maximum possible documentation and follow-up information on all trial deaths.

Interruption of antiretroviral therapy and risk of cardiovascular disease in persons with HIV-1 infection: exploratory analyses from the SMART trial

BACKGROUND

The SMART trial found a raised risk of cardiovascular disease (CVD) events in patients undergoing CD4+ T cell-count guided intermittent antiretroviral therapy (ART) compared with patients on continuous ART. Exploratory analyses were performed to better understand the reasons for this observation.

METHODS

A total of 5,472 patients with CD4+ T-cell counts >350 cells/mm3 were recruited and randomized to either continuous ART (the viral suppression arm; VS) or CD4+ T-cell count-guided use of ART (the drug conservation arm; DC).

RESULTS

Major CVD events developed in 79 patients. The hazard ratio (HR) for risk of CVD events for DC versus VS was 1.57 (95% confidence interval 1.00-2.46; P=0.05). There was no evidence that being off ART or a higher current HIV viral load were associated with increased CVD risk. Total cholesterol and low-density lipoprotein cholesterol were reduced as a result of ART interruption in DC patients but so was high-density lipoprotein (HDL) cholesterol, leading to a net unfavourable change in the total/HDL cholesterol ratio.

CONCLUSIONS

Reasons for the higher risk of CVD for DC compared with VS patients remain unclear. There was no clear evidence to suggest that ART interruption per se or a higher HIV viral load were associated with an increased CVD risk in the DC group. Lipid changes were less favourable among DC compared with VS patients, which could offer a partial explanation.

Influence of the presence of doctors-in-training on the blood pressure of patients: a randomised controlled trial in 22 teaching practices

Until now, no information is available about the effect of the presence of a doctor-in-training on a patient's blood pressure. We tested the hypothesis that the presence of a last year medical student might increase the blood pressure of the patient, in addition to the possible pressor response to the doctor-trainer. Normotensive and hypertensive patients with a minimum age of 25 years, visiting for any reason, were recruited at 22 teaching general practices. Patients were randomised into a 'trainee' group (n=133) and a 'no trainee' (n=129) group. The blood pressure was measured at two subsequent contacts. In the 'trainee' group, a student was present at the first visit only. In the 'no trainee' group, both visits were without student. Both groups had similar anthropometric characteristics at entry. At the first visit, systolic pressure was higher in the 'trainee' group than in the control group (139.5 vs 133.1 mmHg, P=0.004), with a similar trend for diastolic pressure (80.2 vs 77.8 mmHg, P=0.07). From the first contact to the follow-up visit, blood pressure decreased in the trainee group by 4.8 mmHg systolic (P<0.001) and 1.7 mmHg diastolic (P=0.03), whereas the corresponding changes in the control group were -0.1 mmHg (P=0.90) and +1.5 mmHg (P=0.03). Thus, the between group differences in these trends averaging 4.7 mmHg (CI 1.5-7.9, P=0.005) systolic and 3.2 mmHg (CI 1.1-5.3, P=0.003) diastolic were statistically significant. We conclude that in teaching-practices, the presence of a doctor-in-training has a significant pressor effect when an experienced general practitioner measures a patient's blood pressure. If confirmed, our findings imply that doctors should be cautious to initiate or adjust antihypertensive treatment when blood pressure readings are obtained in the presence of a student.