Arginine: mediator or modulator of sepsis?

Arginine is a conditionally essential amino acid that plays pivotal roles in maintaining body homeostasis. Arginine is a substrate for protein synthesis but can also be metabolized to various bioactive compounds that include nitric oxide, ornithine, polyamines, creatine phosphate, agmatine, and dimethylarginines. Arginine produces physiologic effects via nitric oxide dependent and independent pathways. Nitric oxide is important for the modulation of vascular tone, inflammation, immune function, endothelial function, platelet and leukocyte adherence, and neurotransmission. Nitric oxide modulates many biochemical processes important for the response to sepsis. Arginine, independent of nitric oxide, is important for growth, wound healing, cardiovascular function, immune function, inflammatory responses, energy metabolism, urea cycle function, and other metabolic processes. Arginine supplementation improves outcomes in animals with sepsis, wounds, ischemia-reperfusion injury, and following thermal injury. Enteral administration of arginine improves endothelial function but has little effect upon hemodynamics during human sepsis. An analysis of clinical studies using enteral formulas with supplemental arginine suggests benefits upon outcome, with no evidence of significant detrimental effects.     

ROLE OF INTERMEDIARY BIOMARKERS IN DETERMINING THE ANTICANCER EFFICACY OF MARINE COMPOUNDS

In the present study, two of the probable an umor marine compounds, manzamine A and sarcophine, were screened using benzo[a]pyrene (BP)-derived DNA adduct formation in MCF-7 cells as intermediary biomarker. Briefly, MCF-7 cells were treated with the compounds for 24 h followed by treatment with BP (0.5 μM). After 24h incubation, cellular DNA was isolated and analyzed for BP-derived DNA adducts by ³²P-postlabeling technique. Manzamine A and sarcophine increased the BP-DNA adducts by 2 to 4-folds. Further, manzamine A (50 μM) substantially down regulated the expression of p53 while sarcophine (50 μM) slightly induced the level of p21. The residual DNA repair ability was almost completely abolished by manzamine A while sarcophine was ineffective. Based on our preliminary results, these compounds may be classified as potential genotoxic.     

Complications of exteriorized compared with in situ uterine repair at cesarean delivery under spinal anesthesia: a randomized controlled trial

OBJECTIVE: To compare intraoperative complications of exteriorized and in situ uterine repair during elective cesarean delivery under spinal anesthesia. METHODS: This study was a randomized, single-blinded trial in 80 women undergoing elective cesarean delivery under spinal anesthesia. Patients were randomly assigned to exteriorized or in situ uterine repair. Obstetricians were asked to perform assisted delivery of the placenta. Spinal anesthesia and oxytocin management were standardized. Phenylephrine was used to maintain systolic blood pressure within 10% of the baseline. The primary outcome was intraoperative, postdelivery nausea or vomiting. RESULTS: Postdelivery nausea or vomiting (18% compared with 38%; P=.04) and tachycardia (3% compared with 18%; P=.03) were significantly reduced in the in situ group compared with the exteriorized group. The duration of uterine repair was significantly shorter in the exteriorized group (median 10 minutes [first and third quartiles 9, 13], compared with 11 minutes [9, 15]) (P=.04). The duration of surgery (36 minutes [30, 41] compared with 37 minutes [30, 45]) and estimated blood loss (mean+/-standard deviation 625+/-489 mL compared with 653+/-416 mL) were similar between the in situ and the exteriorized groups. There was no correlation between duration of uterine repair and estimated blood loss. CONCLUSION: Exteriorization of the uterus for repair is associated with an increased incidence of nausea and vomiting and tachycardia during cesarean delivery under spinal anesthesia. Uterine repair should be done in situ where possible. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00452972 LEVEL OF EVIDENCE: I.     

Heart Failure after Laboratory Confirmed Influenza Infection (FLU-HF)

Background:Influenza has been shown to exacerbate heart failure (HF). Importantly, no study to date has examined the relationship between HF hospitalizations (HFH) with laboratory confirmed influenza infections. This study evaluated the association between laboratory confirmed influenza infection and HFH in the two largest hospitals in Saskatchewan, Canada.Methods:We used a retrospective self-controlled case series design to evaluate the association between laboratory-confirmed influenza infection and HFH. We compared the incidence ratio for HFH during the influenza risk interval with the control interval. We defined the influenza risk interval as the seven days after a laboratory confirmed influenza result and the control interval as one year before and after the risk interval.Results:We identified 114 HFH that occurred within one year before and after a positive test result for influenza between April 1, 2010, and April 30, 2018. Of these, 28 (28 admissions per week) occurred during the risk interval and 86 (0.853 admissions per week) occurred during the control interval. The incidence ratio of a HFH during the risk interval as compared with the control interval was 33.53 (95% confidence interval [CI], 21.89 to 51.36). A decline in incidence was observed after day seven; between days 8 to 14 and 14 to 28 incidence ratios was 0.91 (95% CI, 0.13 to 6.52) and 0.91 (95% CI, 0.22 to 3.68) respectively.Conclusion:We have observed a significant association between acute influenza infection and HFH. However, further research with a larger sample size and involving a multicenter setting is warranted.Highlights

• Influenza may contribute and exacerbate heart failure events especially during annual influenza season.
• Early identification of influenza among patients with heart failure, could lead to earlier treatment with antiviral medication, reduce unnecessary antibiotic use, and tail off the morbidity and mortality.
• In this study, despite our efficient study design, our sample size was limited to only the two largest hospitals in the province, possibly excluding a significant population in remote areas.

     

Modelling effects of bromide ion concentration on the formation of brominated trihalomethanes

A series of statistically‐based models have been developed for predicting the formation of individual trihalomethane (THM) species, ranging from chloroform to bromoform, as a function of various reaction conditions. These equations allow a quantitative assessment of bromide effects on overall THM formation as well as THM speciation.     

Performance of Microchannel Heat Sink Made of Silicon Material with the Two-Sided Wedge

New designs of the microchannel with a two-sided wedge shape at the base were studied numerically. Five different wedge angles ranging from 3° to 15° were incorporated into the microchannel design. Simulation of this novel microchannel was carried out using Computational Fluid Dynamics (CFD). Three-dimensional models of the microchannel heat sink were created, discretized, and based on Navier–Stokes and energy equations; laminar numerical solutions were obtained for heat transfer and pressure drop. Flow characteristics of water as coolant in a microchannel were studied. It was observed that numerical results are in good agreement with experimental results. It was found that the Nusselt number and friction factor are significantly varied with the increase in Reynolds number. The Nusselt number varies in the following ranges of 5.963–8.521, 5.986–8.550, 6.009–8.568, 6.040–8.609, and 6.078–8.644 at 3°, 6°, 9°, 12°, and 15°, respectively. The microchannel with a wedge angle of 15° was found to be better in terms of Nusselt number and thermo-hydraulic performance. The enhancement in the Nusselt number is found as 1.017–1.036 for a wedge angle of 15°; however, friction factors do not show the perceptible values at distinct values of wedge angle. Moreover, the thermo-hydraulic performance parameters (THPP) were evaluated and found to be maximum in the range of 1.027–1.045 for a wedge angle of 15°. However, minimum THPP was found in the range of 1.005–1.0185 for a wedge angle of 3°.