Rate control with intravenous diltiazem, verapamil, and metoprolol in acute atrial fibrillation with rapid ventricular rate.

INTRODUCTION: Diltiazem is a preferred agent for rate control in atrial fibrillation due to its quick onset, minimal side effects, and low cost. Due to its intermittent national shortage since February 2018, the utilization of intravenous metoprolol and verapamil has increased. This study investigated the effect of intravenous diltiazem, metoprolol, and verapamil on rate control in patients with atrial fibrillation with rapid ventricular rate. METHODS: This study was a retrospective, single-center, cohort study conducted in patients with acute atrial fibrillation receiving intravenous diltiazem, metoprolol, or verapamil for rapid ventricular rate between 1 January 2012 and 31 August 2018. The primary outcome was the incidence of patients who achieved a rate less than 100 bpm within 1 h of treatment. Secondary outcomes included time to achieve rate control, heart rate at 30 min and 1 h after administration, bradycardia and hypotension incidence, the requirement of other rate control agent(s), inpatient admission, length of stay, and mortality. RESULTS: A total of 73 patients were included in the study. At 1 h after receiving the initial rate control drug, there was no statistically significant difference between diltiazem, metoprolol, and verapamil in achieving rate control. Median time to ventricular rate control was 166 min in the diltiazem group, 297 min in the metoprolol group, and 100.5 min in the verapamil group. CONCLUSION: There was no difference in achieving rate control when using intravenous diltiazem, metoprolol, or verapamil. Any of the three rate control agents may be used for rate control. However, further studies are needed to determine which agent is superior for rate control.

Characterization of Solanum melongena Thioesterases Related to Tomato Methylketone Synthase 2.

2-Methylketones are involved in plant defense and fragrance and have industrial applications as flavor additives and for biofuel production. We isolated three genes from the crop plant Solanum melongena (eggplant) and investigated these as candidates for methylketone production. The wild tomato methylketone synthase 2 (ShMKS2), which hydrolyzes ß-ketoacyl-acyl carrier proteins (ACP) to release ß-ketoacids in the penultimate step of methylketone synthesis, was used as a query to identify three homologs from S. melongena: SmMKS2-1, SmMKS2-2, and SmMKS2-3. Expression and functional characterization of SmMKS2s in E. coli showed that SmMKS2-1 and SmMKS2-2 exhibited the thioesterase activity against different ß-ketoacyl-ACP substrates to generate the corresponding saturated and unsaturated ß-ketoacids, which can undergo decarboxylation to form their respective 2-methylketone products, whereas SmMKS2-3 showed no activity. SmMKS2-1 was expressed at high level in leaves, stems, roots, flowers, and fruits, whereas expression of SmMKS2-2 and SmMKS2-3 was mainly in flowers and fruits, respectively. Expression of SmMKS2-1 was induced in leaves by mechanical wounding, and by methyl jasmonate or methyl salicylate, but SmMKS2-2 and SmMKS2-3 genes were not induced. SmMKS2-1 is a candidate for methylketone-based defense in eggplant, and both SmMKS2-1 and SmMKS2-2 are novel MKS2 enzymes for biosynthesis of methylketones as feedstocks to biofuel production.

Contrasting acclimation abilities of two dominant boreal conifers to elevated CO2 and temperature.

High latitude forests will experience large changes in temperature and CO2 concentrations this century. We evaluated the effects of future climate conditions on 2 dominant boreal tree species, Pinus sylvestris L. and Picea abies (L.) H. Karst, exposing seedlings to 3 seasons of ambient (430 ppm) or elevated CO2 (750 ppm) and ambient temperatures, a + 4 °C warming or a + 8 °C warming. Pinus sylvestris responded positively to warming: seedlings developed a larger canopy, maintained high net CO2 assimilation rates (Anet ), and acclimated dark respiration (Rdark ). In contrast, carbon fluxes in Picea abies were negatively impacted by warming: maximum rates of Anet decreased, electron transport was redirected to alternative electron acceptors, and thermal acclimation of Rdark was weak. Elevated CO2 tended to exacerbate these effects in warm-grown Picea abies, and by the end of the experiment Picea abies from the +8 °C, high CO2 treatment produced fewer buds than they had 3 years earlier. Treatments had little effect on leaf and wood anatomy. Our results highlight that species within the same plant functional type may show opposite responses to warming and imply that Picea abies may be particularly vulnerable to warming due to low plasticity in photosynthetic and respiratory metabolism.