Overexpression of phospholipid: diacylglycerol acyltransferase in Brassica napus results in changes in lipid metabolism and oil accumulation.

The regulation of lipid metabolism in oil seeds is still not fully understood and increasing our knowledge in this regard is of great economic, as well as intellectual, importance. Oilseed rape (Brassica napus) is a major global oil crop where increases in triacylglycerol (TAG) accumulation have been achieved by overexpression of relevant biosynthetic enzymes. In this study, we expressed Arabidopsis phospholipid: diacylglycerol acyltransferase (PDAT1), one of the two major TAG-forming plant enzymes in B. napus DH12075 to evaluate its effect on lipid metabolism in developing seeds and to estimate its flux control coefficient. Despite several-fold increase in PDAT activity, seeds of three independently generated PDAT transgenic events showed a small but consistent decrease in seed oil content and had altered fatty acid composition of phosphoglycerides and TAG, towards less unsaturation. Mass spectrometry imaging of seed sections confirmed the shift in lipid compositions and indicated that PDAT overexpression altered the distinct heterogeneous distributions of phosphatidylcholine (PC) molecular species. Similar, but less pronounced, changes in TAG molecular species distributions were observed. Our data indicate that PDAT exerts a small, negative, flux control on TAG biosynthesis and could have under-appreciated effects in fine-tuning of B. napus seed lipid composition in a tissue-specific manner. This has important implications for efforts to increase oil accumulation in similar crops.

Increase in lysophosphatidate acyltransferase activity in oilseed rape (Brassica napus) increases seed triacylglycerol content despite its low intrinsic flux control coefficient.

Lysophosphatidate acyltransferase (LPAAT) catalyses the second step of the Kennedy pathway for triacylglycerol (TAG) synthesis. In this study we expressed Trapaeolum majus LPAAT in Brassica napus (B. napus) cv 12075 to evaluate the effects on lipid synthesis and estimate the flux control coefficient for LPAAT. We estimated the flux control coefficient of LPAAT in a whole plant context by deriving a relationship between it and overall lipid accumulation, given that this process is a exponential. Increasing LPAAT activity resulted in greater TAG accumulation in seeds of between 25% and 29%; altered fatty acid distributions in seed lipids (particularly those of the Kennedy pathway); and a redistribution of label from 14 C-glycerol between phosphoglycerides. Greater LPAAT activity in seeds led to an increase in TAG content despite its low intrinsic flux control coefficient on account of the exponential nature of lipid accumulation that amplifies the effect of the small flux increment achieved by increasing its activity. We have also developed a novel application of metabolic control analysis likely to have broad application as it determines the in planta flux control that a single component has upon accumulation of storage products.

Transgenic manipulation of triacylglycerol biosynthetic enzymes in B. napus alters lipid-associated gene expression and lipid metabolism.

Oilseed rape (Brassica napus) is an important crop that is cultivated for the oil (mainly triacylglycerol; TAG) it produces in its seeds. TAG synthesis is controlled mainly by key enzymes in the Kennedy pathway, such as glycerol 3-phosphate acyltransferase (GPAT), lysophosphatidate acyltransferase (LPAT) and diacylglycerol acyltransferase (DGAT) but can also be produced from phosphoglycerides such as phosphatidylcholine (PC) by the activity of the enzyme phospholipid: diacylglycerol acyltransferase (PDAT). To evaluate the potential for these enzymes to alter oil yields or composition, we analysed transgenic B. napus lines which overexpressed GPAT, LPAT or PDAT using heterologous transgenes from Arabidopsis and Nasturtium and examined lipid profiles and changes in gene expression in these lines compared to WT. Distinct changes in PC and TAG abundance and spatial distribution in embryonic tissues were observed in some of the transgenic lines, together with altered expression of genes involved generally in acyl-lipid metabolism. Overall our results show that up-regulation of these key enzymes differentially affects lipid composition and distribution as well as lipid-associated gene expression, providing important information which could be used to improve crop properties by metabolic engineering.

Overnight cross-coverage on hospital medicine services: perceived workload based on patient census, pager volumes, and patient acuity.

OBJECTIVE: Little is understood about what contributes to perceived workload for those providing overnight coverage to hospitalized patients overnight, which limits the ability to modify these factors or to proactively identify appropriate staffing levels. The objective of this study is to understand the major contributors to perceived overnight cross-coverage workload. METHODS: Cross-covering advanced practice providers (APPs) in a large academic hospitalist group completed the National Aeronautics and Space Administration Task Load Index (NASA-TLX) at the end of each night shift. Other shift characteristics were collected, including patient load, assigned action items, watcher/unstable patients, newly admitted patients, number of units covered, total pages, peak pager density, rapid response team (RRT) activations, and intensive care unit (ICU) transfers. RESULTS: For 14 APP participants, who completed 271 post-shift surveys, the mean (SD) patient load was 49.9 (6.4) patients per night, and providers received a mean (SD) of 40.8 (13.7) total pages per shift. Mean (SD) NASA-TLX score was 35.1 (19.0). In multivariate modeling, total pages, action items, and any RRT or ICU transfer were associated with significant increases in the mean NASA-TLX score, with estimated effect sizes of 0.5, 0.8, and 14.3, respectively, per 1-unit increase in each shift characteristic. The greatest cumulative contributor to perceived workload was total number of pages, followed by the presence of any RRT activation/ICU transfer, with estimated effect sizes of 20.4 and 14.9, respectively. CONCLUSIONS: Total number of pages was the greatest contributor to perceived workload. This study suggests that quality improvement initiatives designed to improve pager communication may considerably improve provider-perceived workload.

Retrospective Analysis of Gabapentin for Alcohol Withdrawal in the Hospital Setting: The Mayo Clinic Experience.

OBJECTIVE: To evaluate the efficacy and safety of a fixed-dose gabapentin taper protocol for alcohol withdrawal in hospitalized patients. PATIENTS AND METHODS: We retrospectively identified patients admitted to the hospital from January 1, 2016, to April 30, 2018, for alcohol withdrawal syndrome. Based on the treatment that patients received, they were divided into the gabapentin, benzodiazepine, and combination treatment groups. The primary outcome was length of stay, defined as time from admission to either discharge or 36 hours with Clinical Institute Withdrawal Assessment (CIWA) score less than 10. Inverse probability of treatment weight was used to account for differences in baseline characteristics between groups. RESULTS: A total of 443 patients met criteria for inclusion (128, 253, and 62 patients in the gabapentin, benzodiazepine, and combination groups, respectively). Baseline characteristics were similar among all groups. The median gabapentin group length of stay was 4.0 hours shorter than the benzodiazepine group (P=.012). Maximum CIWA score was 2.2 points lower in the gabapentin group (P=.003). No statistical differences were noted among safety outcomes, including incidence of seizure, intensive care unit transfer, or delirium tremens. Results were not statistically altered by inverse probability of treatment weight analysis. CONCLUSION: A fixed-dose gabapentin taper protocol appears to be an effective and safe alternative to CIWA-driven benzodiazepines in patients hospitalized with alcohol withdrawal syndrome, though further research is necessary to define the potential subpopulations that benefit most.

Transition of Intravenous Treprostinil to Oral Therapy in a Patient with Functional Class IV Chronic Thromboembolic Pulmonary Hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) occurs when pulmonary emboli fail to resolve with anticoagulation. For patients with inoperable or residual CTEPH, riociguat is currently the only therapy approved by the United States Food and Drug Administration. However, some patients with CTEPH may require therapy beyond riociguat, such as intravenous prostacyclins, which can present significant administration challenges in patients with complex comorbid conditions. We describe a 42-year-old man with T12 paraplegia complicated by CTEPH (functional class IV with substantial right ventricular dysfunction) and severe pressure ulcers. In order to facilitate goals of care (hospital discharge to a skilled nursing facility where parenteral prostanoids could not be administered), he underwent rapid transition from intravenous treprostinil to oral selexipag in the form of a cross-taper over 6 days. The patient required readmission due to worsening symptoms and was transitioned back to intravenous treprostinil; he tolerated conversion to oral treprostinil for approximately 4 months, but it was subsequently discontinued due to nausea and modified goals of care. The patient underwent transition to hospice care 3 months later and eventually died from clinical deterioration. To our knowledge, this is the first report to describe transition from intravenous treprostinil to selexipag as well as conversion from parenteral treprostinil to oral treprostinil in a patient with CTEPH and illustrates the approaches to and potential issues with prostanoid transitions. Additional observations are necessary to better understand the relative roles of selexipag and oral treprostinil regarding comparative efficacy and tolerability.

Characteristics and Outcomes of Fasting Orders Among Medical Inpatients.

While many hospitalized patients have orders to fast in preparation for interventions, the extent to which these orders are necessary or adhere to evidence-based durations is unknown. In this study, we analyzed the length, indication, and associated outcomes of nil per os (NPO) orders for general medicine patients at an academic institution in the United States, and compared them to the best available evidence for recommended length of NPO. Of 924 NPO orders assessed, the indicated intervention was not performed for 183 (19.8%) orders, largely due to a change in plan (75/183, 41.0%) or scheduling barriers (43/183, 23.5%). When analyzed by indication, the median duration of NPO orders ranged from 8.3 hours for kidney ultrasound to 13.9 hours for upper endoscopy. For some indications, the literature suggested NPO orders may be unnecessary. Furthermore, in indications for which NPO was deemed necessary in the literature, the duration of most NPO orders was much longer than minimally required. These results suggest the need for establishing more robust practice guidelines or institutional protocols for NPO orders. Journal of Hospital Medicine 2017;12:36-39.

Impact of Stress Testing for Coronary Artery Disease Screening in Asymptomatic Patients With Diabetes Mellitus: A Community-Based Study in Olmsted County, Minnesota.

OBJECTIVE: To evaluate the impact of screening stress testing for coronary artery disease in asymptomatic patients with diabetes in a community-based population. PATIENTS AND METHODS: This observational study included 3146 patients from Olmsted County, Minnesota, with no history of coronary artery disease or cardiac symptoms in whom diabetes was newly diagnosed from January 1, 1992, through December 31, 2008. With combined all-cause mortality and myocardial infarction as the primary outcome, weighted Cox proportional hazards regression was performed with screening stress testing within 2 years of diabetes diagnosis as the time-dependent covariate. For descriptive analysis, participants were classified by their clinical experience during the first 2 years postdiagnosis as screened (asymptomatic, underwent stress test), unscreened (asymptomatic, no stress test), or symptomatic (experienced symptoms or event). RESULTS: Among the screened and unscreened participants, 54% (1358 of 2538) were men; the mean (SD) age at diabetes diagnosis was 55 years (13.8 years), and 97% (2442 of 2520) had type 2 diabetes. In event-free survival analysis, 292 patients comprised the screened cohort and 2246 patients comprised the unscreened cohort. Death or myocardial infarction occurred in 454 patients (32 patients in the screened cohort and 422 in the unscreened cohort [5-year rate, 1.9% and 5.3%, respectively]) during median (interquartile range) follow-up of 9.1 years (5.3-12.5 years). Screening stress testing was associated with improved event-free survival (hazard ratio, 0.61; P=.004), independent of cardiac risk factors. However, while stress test results were abnormal in 47 of the 292 screened patients (16%), only 6 (2%) underwent coronary revascularization. CONCLUSION: Although screening cardiac stress testing in asymptomatic patients with diabetes in this community-based population was associated with improvement in long-term event-free survival, this result does not appear to occur by coronary revascularization alone.

Frequency and Appropriateness of Fasting Orders in the Hospital.

OBJECTIVE: To evaluate the frequency and appropriateness of nil per os (nothing by mouth) (NPO) orders and determine the number of meals missed because of these orders among hospitalized patients. PATIENTS AND METHODS: We retrospectively analyzed inpatient NPO orders at an academic institution in the United States. The frequency and duration of NPO orders and the number of meals missed because of these orders were assessed for adult patients admitted to the hospital medicine services from January 1, 2013, through December 31, 2013, with a hospital stay of 2 or more and 30 or fewer days. Two blinded reviewers assessed if the order could be avoided or the period shortened for a random sample of NPO orders of 120 or more minutes' duration that were written for patients on the general medicine ward. RESULTS: A total of 3641 NPO orders were identified. At least one NPO order was placed in 46.6% of the admissions (2211 of 4743). The median duration of NPO orders was 12.8 hours (interquartile range, 9.2-17.3 hours), resulting in 2 (interquartile range, 1-4) missed meals. Of 1130 NPO orders reviewed, 263 (23.3%; 95% CI, 20.9%-25.8%) were deemed avoidable (κ statistic, 0.68), and 482 (42.7%) were unavoidable but led to more missed meals than needed. Taken together, patients could have had 44.8% of the meals (1085 of 2424; 95% CI, 42.8%-46.7%) missed due to NPO orders. CONCLUSION: Approximately half of the patients admitted to the hospital medicine services experienced a period of fasting. One in 4 NPO orders and nearly half of missed meals could have been avoided. Further study is warranted to assess the generalizability of our findings.