Artificial metalloenzymes based on biotin-avidin technology for the enantioselective reduction of ketones by transfer hydrogenation

Most physiological and biotechnological processes rely on molecular recognition between chiral (handed) molecules. Manmade homogeneous catalysts and enzymes offer complementary means for producing enantiopure (single-handed) compounds. As the subtle details that govern chiral discrimination are difficult to predict, improving the performance of such catalysts often relies on trial-and-error procedures. Homogeneous catalysts are optimized by chemical modification of the chiral environment around the metal center. Enzymes can be improved by modification of gene encoding the protein. Incorporation of a biotinylated organometallic catalyst into a host protein (avidin or streptavidin) affords versatile artificial metalloenzymes for the reduction of ketones by transfer hydrogenation. The boric acid.formate mixture was identified as a hydrogen source compatible with these artificial metalloenzymes. A combined chemo-genetic procedure allows us to optimize the activity and selectivity of these hybrid catalysts: up to 94% (R) enantiomeric excess for the reduction of p-methylacetophenone. These artificial metalloenzymes display features reminiscent of both homogeneous catalysts and enzymes.     

Emergency Department influenza vaccination campaign allows increasing influenza vaccination coverage without disrupting time interval quality indicators

To evaluate the impact of an influenza vaccination (IV) coverage (IVC) in a vaccination campaign of an Emergency Department (EDVC) and its impact on ED time interval quality indicators. We conducted a 4 year observational study, with an intervention during the 4th year. IVC was calculated during pre-and early-epidemic periods. During the final period, a 12 weeks EDVC was implemented. Physicians and nurses were trained and sensitized in the importance of vaccination, and their role in the prevention of severe forms of influenza was reinforced. The vaccine was proposed by physicians and nurses, and delivered by them. Repeated measures ANOVA is a validated method for related not independent groups (https://statistics.laerd.com/statistical-guides/repeated-measures-anova-statistical-guide.php). Overall, IVC was 987/3191 (30.9%) with an increasing trend from 28.8 to 33.2%. In the fourth period, out of 868 patients identified with IV indication, 288 had already been vaccinated (IVC?33.2%). After excluding patients presenting criteria of exclusion, IV was proposed to 475 patients: 317 (66.7%) accepted. The vaccination rate after patient’s acceptance was 89.6% (288/317). At the end of the EDVC, influenza vaccination coverage was 572 (284?+?288)/868 (65.9%). The delay between arrival at the ED and seeing the triage nurse and physician as well as the overall ED length of stay were not modified during the study period and before and during EDVC. EDVC effectively doubled the influenza vaccination coverage, without modifying ED time interval quality indicators.     

Effects of interleukin-2 therapy combined with highly active antiretroviral therapy on immune restoration in HIV-1 infection: a randomized controlled trial

BACKGROUND: Intermittent interleukin-2 (IL-2) therapy leads to a sustained increase of CD4 T cells in HIV-1-infected patients. METHODS: Symptom-free HIV-1-infected patients who were naive to all antiretroviral drugs (n = 68) and/or to protease inhibitors (n = 50) and had a CD4 cell count of 200-550 x 10(6) cells/l were randomly assigned to start lamivudine/stavudine/indinavir alone (controls) or combined from week 4 with subcutaneous IL-2 (5 x 10(6) IU twice daily for 5 days: every 4 weeks for three cycles, then every 8 weeks for seven cycles). Immunological and virological results were monitored until week 74. RESULTS: CD4 T cell counts increased more in the IL-2 group than in the controls (median increases 865 and 262 x 10(6) cells/l, respectively; P < 0.0001); an 80% increase in CD4 T cells was achieving by 89% of the IL-2 group and by 47% of the controls (P < 0.0001). Decrease of plasma viral loads was similar in both groups. Compared with controls, IL-2 induced a greater increase of naive and memory CD4 T cells, lymphocyte expression of CD28 and CD25 (P < 0.0001) and natural killer cells (P < 0.001). In a logistic regression analysis, odds of being responders to recall antigens was 8.5-fold higher in IL-2 recipients (P = 0.002) than in controls. The former experienced a higher level of antibody response to tetanus vaccination at week 64 than controls (32 and 8 haemagglutinating units/ml, respectively; P = 0.01). CONCLUSIONS: The combination of antiviral drugs and IL-2 induced a greater expansion and function of CD4 T cells than antiretroviral drugs alone.     

Quantitative study of digestive enzyme secretion and gastrointestinal lipolysis in chronic pancreatitis.

BACKGROUND & AIMS: The contribution of human gastric lipase (HGL) to the overall lipolysis process in chronic pancreatitis (CP), as well as the relative pancreatic enzyme levels, rarely are addressed. This study was designed to quantify pancreatic and extrapancreatic enzyme output, activity, and stability in CP patients vs. healthy volunteers. METHODS: Healthy volunteers (n = 6), mild CP patients (n = 5), and severe (n = 7) CP patients were intubated with gastric and duodenal tubes before the administration of a test meal. HGL, human pancreatic lipase (HPL), chymotrypsin, and amylase concentrations were assessed in gastric and duodenal samples by measuring the respective enzymatic activities. Intragastric and overall lipolysis levels at the angle of Treitz were estimated based on quantitative analysis of lipolysis products. Similar analyses were performed on duodenal contents incubated ex vivo for studying enzyme stability and evolution of lipolysis. RESULTS: Although HPL, chymotrypsin, and amylase outputs all were extremely low, HGL outputs in patients with severe CP (46.8 +/- 31.0 mg) were 3-4-fold higher than in healthy controls (13.3 +/- 13.8 mg). Intragastric lipolysis did not increase, however, in patients with severe CP, probably because of the rapid decrease in the pH level of the gastric contents caused by a higher gastric acid secretion. HGL remains active and highly stable in the acidic duodenal contents of CP patients, and, overall, can achieve a significant lipolysis of the dietary triglycerides (30% of the control values) in the absence of HPL. CONCLUSIONS: Although all pancreatic enzyme secretions are simultaneously reduced in severe CP, gastric lipase can compensate partly for the loss of pancreatic lipase but not normalize overall lipolytic activity.     

Oxygen uptake efficiency slope, a new submaximal parameter in evaluating exercise capacity in chronic heart failure patients

Background

The oxygen uptake efficiency slope (OUES) is a new submaximal parameter which objectively predicts the maximal exercise capacity in children and healthy subjects. However, the usefulness of OUES in adult patients with and without advanced heart failure remains undetermined. The present study investigates the stability and the usefulness of OUES in adult cardiac patients with and without heart failure.

Methods

Forty-five patients with advanced heart failure (group A) and 35 patients with ischemic heart disease but normal left ventricular ejection fraction (group B) performed a maximal exercise test. PeakVO₂ and percentage of predicted peakVO₂ were markers of maximal exercise capacity, whereas OUES, ventilatory anaerobic threshold (VAT), and slope VE/VCO₂ were calculated as parameters of submaximal exercise.

Results

Group A patients had lower peakVO₂ (P < .001), lower percentage of predicted peakVO₂ (P = .001), lower VAT (P < .05), steeper slope VE/VCO₂ (P < .001), and lower OUES (P < .02). Within group A, significant differences were found for VAT, slope VE/VCO₂, and OUES (all P < .01) between patients with peakVO₂ above and below 14 mL O₂/kg/min. Of all the submaximal parameters, VAT correlated best with peakVO₂ (r =.814, P < .01) followed by OUES/kg (r = .781, P < .01), and slope VE/VCO₂ (r = −.492, P < .001). However, VAT could not be determined in 18 (23%) patients.

Conclusions

OUES remains stable over the entire exercise duration and is significantly correlated with peakVO₂ in adult cardiac patients with and without impaired LVEF. Therefore, OUES could be helpful to assess exercise performance in advanced heart failure patients unable to perform a maximal exercise test. Further studies are needed to confirm our hypothesis.