ABSTRACT
The use of differential mobility spectrometry at low pressure coupled to liquid chromatography-mass spectrometry (LC-vDMS-MS) was investigated for the analysis of 13 drugs of abuse (DoA) including the following: cocaine, ecgonine methyl ester, cocaethylene, benzoylecgonine, norcocaine, tramadol, isomeric pairs of metabolites; O-desmethyl-cis-tramadol and N-desmethyl-cis-tramadol, and cannabinoids: Δ9-tetrahydrocannabinol, Δ9-tetrahydrocannabidiol, 11-hydroxy-Δ9-tetrahydrocannabinol, 11-nor-9carboxy-Δ9-tetrahydrocannabinol, and 11-nor-9carboxy-Δ9-tetrahydrocannabinol glucuronide. Different parameters were optimized for isomeric separation, such as LC mobile phase composition (20%-100% methanol acetonitrile and isopropanol, flow rate: 8-100 µL/min) and DMS separation voltage. Methanol and acetonitrile significantly affected the compensation voltage of the analytes and improved DMS separation. A short trap/elute LC-vDMS-SIM/MS screening method of 1 min was developed to quantify 11 drugs of abuse (except THC/CBD), in addition to a 4-min LC-vDMS-SIM/MS method to identify and quantify five cannabinoids including the isomers THC/CBD and three THC metabolites. THC is the principal psychoactive constituent of cannabis and is a controlled substance in comparison to its isomeric counterpart CBD; this highlights the importance and challenges to resolve these isomeric pairs by analytical techniques. The signal responses were linear over a concentration range of 0.005-10 µg/mL for the DoA and 1-1000 ng/mL for cannabinoids. The intraday and interday precision were better than 12.2% and accuracy better than 115%. Urine samples from subjects who tested positive for THC and/or cocaine during roadside drug testing were evaluated to assess the performance of the methods LC-vDMS-SIM/MS and LC-MRM/MS. Results show that the developed LC-vDMS-SIM/MS method presents similar performance to LC-MRM/MS with improved sample throughput.
ABSTRACT
The benefit of combining liquid chromatography (LC), supercritical fluid chromatography (SFC) and vacuum Differential Mobility Spectrometry - Mass Spectrometry (vDMS-MS) was investigated for the analysis of fourteen diastereomeric pyrrolizidine alkaloids (PA); intermedine, echinatine, lycopsamine, indicine, intermedine-N-oxide, echinatine-N-oxide, indicine-N-oxide, lycopsamine-N-oxide, senecivernine, senecionine, jacobine, senecivernine-N-oxide, senecionine-N-oxide, retrorsine. The mobile phase composition (15-100% MeOH and ACN), flow rate (8-100 µL/min), vDMS cell pressure, and F value showed an effect on the mobility behavior of the analytes. At 15% MeOH with a flow rate of 100 µL/min and 33 mbar vDMS pressure, 8 out 14 PA could be partially or totally separated by vDMS-MS. As well as providing an additional separation dimension vDMS improved the selectivity and a 5-minute assay method was developed for the quantification of 10 out of 14 single diastereomeric PA in tea samples, using a short LC column-switching and hyphenated to vDMS-MS in the selected ion monitoring mode. The performance of the method was found to be comparable with a 12-minute standard LC-MS/MS method using detection in the selected reaction monitoring mode. Additionally, the combination of vDMS and SFC-MS was investigated and suggests that the mixture of CO2/MeOH influences the CV shifting of the PA to more negative compensation voltage, and the signal-to-noise ratio is improved by a factor of three compared to SFC-MS without vDMS.
Subject(s)
Pyrrolizidine Alkaloids , Tandem Mass Spectrometry , Chromatography, Liquid , Tandem Mass Spectrometry/methods , Vacuum , Pyrrolizidine Alkaloids/analysis , Spectrum Analysis , Oxides , TeaABSTRACT
The effect of LC mobile phase composition and flow rate (2-50 µL/min) on mobility behavior in vacuum differential mobility spectrometry (vDMS) was investigated for electrosprayed isobaric antidepressant drugs (AD); amitriptyline, maprotiline, venlafaxine; and structurally related antidepressants nortriptyline, imipramine, and desipramine. While at 2 µL/min, no difference in compensation voltage was observed with methanol and acetonitrile, at 50 µL/min, acetonitrile used for LC elution of analytes enabled the selectivity of the mobility separation to be improved. An accurate and sensitive method could be developed for the quantification of six AD drugs in human plasma using trap/elute micro-LC setup hyphenated to vDMS with mass spectrometric detection in the selected ion monitoring mode. The assay was found to be linear over three orders of magnitude, and the limit of quantification was of 25 ng/mL for all analytes. The LC-vDMS-SIM/MS method was compared to a LC-MRM/MS method, and in both cases, inter-assay precisions were lower than 12.5 and accuracies were in the range 91.5-110%, but with a four times reduced analysis time (2 min) for the LC-vDMS-SIM/MS method. This work illustrates that with vDMS, the LC mobile phase composition can be used to tune the ion mobility separation and to improve assay selectivity without additional hardware.
Subject(s)
Imipramine , Nortriptyline , Acetonitriles , Amitriptyline , Antidepressive Agents , Desipramine , Humans , Maprotiline , Mass Spectrometry , Methanol , Reproducibility of Results , Spectrum Analysis , Vacuum , Venlafaxine HydrochlorideABSTRACT
Orbital frequency analyzer (OFA) is one of the electrostatic ion trap mass analysers for FTMS, which offers ultrahigh mass resolution and high ion charge capacity. In order to analyze multiply charged proteins and other large biological particles by means of charge detection mass spectrometry, a data processing algorithm was created to suit the image charge signal of nonharmonic waveform nature. The algorithm is capable of detecting collisions between ions and residual gas molecules, to determine lifetime of ions, and to evaluate the charge and mass values for ions having lifetime above a threshold. With the filtering of the lifetime and charge value, the chemical noise from small molecules and protein fragments can be eliminated in the reconstructed spectrum, facilitating measurement of protein content at a very low concentration, down to tens of nanomolars. The standard deviation of charge measurement is between 1.1 to 1.8 e for ions with oscillation lifetimes from 1 to 0.4 s, and this in turn determines the CDMS spectrum mass peak width. It has been found that the lower voltage setting of the OFA results in a larger population of ions surviving for longer times and thus produces narrower mass peak width. While OFA is able to run multiplexed CDMS without ion motion interference, coexisting ions of the same or very close m/z can cause interference between their image charge signals, which increases the error in charge determination.
ABSTRACT
BACKGROUND: Pineal tumors are very rarely encountered, with an incidence of <1% of intracranial lesions in adults. Life-threatening hydrocephalus due to obstruction of the third ventricle can result from the location of these tumours. Endoscopic third ventriculostomy (ETV) and tumor biopsy is a safe and feasible strategy, particularly if the tumor appears benign. This mitigates the high risks of uncontrollable venous bleeding from open and stereotactic biopsies. While typically performed using either ipsilateral single or dual bur holes, the location of the tumor may require modifications to the standard endoscopic techniques. CASE DESCRIPTION: A 55-year-old male presented with signs of intracranial hypertension and was found to have obstructive hydrocephalus due to a pineal tumour. The tumour displayed a right-sided dominance when the pre-operative imaging was assessed, which would risk forniceal injury if biopsied via a right-sided burr hole. Craniometric measurements revealed a superior trajectory to the tumour via the left foramen of Monro. A biforaminal approach was performed, with a traditional ETV using a right coronal bur hole and biopsy via a left frontal bur hole. This minimized forniceal stretching and allowed a safe biopsy. CONCLUSION: The bi-foraminal approach has not been widely described in the literature but can potentially avoid morbidity with biopsy in patients with right-sided pineal tumours. We believe this technique should be considered, particularly in low-resource settings where neuroendoscopy is not commonly done, and where the use of ipsilateral single or dual-bur holes may lead to forniceal injury.
ABSTRACT
Background: Pseudomonas aeruginosa is isolated at variable rates from intra-abdominal infections (IAI). Not all recommended empiric regimens for IAI include anti-Pseudomonas aeruginosa activity, for example, ceftriaxone and metronidazole. We hypothesized that within an adult population, Pseudomonas aeruginosa is a relatively rare isolate and has no association with mortality, and thus, empiric therapy with anti-Pseudomonas aeruginosa activity is not warranted. Patients and Methods: All IAI with positive cultures treated between 1997 and 2017 at a single institution were analyzed. This data set was divided into two cohorts, namely, those with cultures positive for Pseudomonas aeruginosa and those without. Demographics and in-hospital mortality were compared by Student t-test and χ2 analysis. Predictors of isolation of Pseudomonas aeruginosa and in-hospital mortality were done by logistic regression (LR) analysis. Results: In total, 2,420 IAIs were identified, 104 (4.3%) with Pseudomonas aeruginosa and 2,316 (95.7%) without. Major demographic differences between patients with Pseudomonas aeruginosa and those without included a higher rate of health-care-associated infections (87/104, 83.7% vs. 621/2316, 26.8%; p = 0.02), a higher rate of intensive care unit (ICU)-acquired infections (23/104, 22.1% vs. 329/2316, 14.2%; p = 0.04) and a higher Acute Physiology and Chronic Health Evaluation (APACHE) II score (17.7 ± 0.8 vs. 14.5 ± 0.2; p < 0.0001). There was an increased rate of Pseudomonas aeruginosa isolation with increasing APACHE II score. Independent predictors of isolation of Pseudomonas aeruginosa by LR included APACHE II score and days of hospitalization prior to diagnosis. Crude in-hospital mortality was similar between groups: Pseudomonas aeruginosa 14/104 (13.5%) and 276/2316 (11.9%), p = 0.79. After controlling for age, gender, APACHE II, prior transfusion, immunosuppression status, solid organ transplant status, healthcare-association, and days of hospitalization prior to diagnosis, the isolation of Pseudomonas aeruginosa was not associated with mortality. Conclusion: Pseudomonas aeruginosa is infrequently isolated and overall not associated with mortality. Nonetheless, there may be a population that merits empiric anti-Pseudomonas aeruginosa therapy: those with APACHE II ≥20 or a significant length of hospitalization prior to diagnosis.
Subject(s)
Cross Infection , Intraabdominal Infections , Pseudomonas Infections , APACHE , Adult , Cross Infection/drug therapy , Cross Infection/epidemiology , Humans , Intensive Care Units , Intraabdominal Infections/drug therapy , Intraabdominal Infections/epidemiology , Oxazolidinones , Pseudomonas Infections/drug therapy , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa , Retrospective StudiesABSTRACT
OBJECTIVE: We evaluated the outcomes and complications of transcarotid artery revascularization (TCAR) outside of academic vascular surgery programs. METHODS: An institutional review board-approved retrospective study was performed. Data from all cases of TCAR performed at a community hospital from May 2017 to February 2020 were collected and analyzed. Seven vascular surgeons performed the procedures after receiving appropriate training. The primary outcomes included technical success, the need for further revascularization, and major adverse events (death, cerebrovascular accident [CVA], myocardial infarction). The secondary outcomes included other adverse events and complications. The outcomes were assessed in the perioperative and 30-day follow-up periods. RESULTS: During a 33-month period, TCAR was completed in 147 of 149 attempted cases (98.7%). No patients required further revascularization. The perioperative and 30-day major adverse event rates were 0.7% (n = 1) and 3.4% (n = 5), respectively. One case of a minor perioperative CVA occurred. At 30 days, one patient had died. The 30-day complications included CVA (n = 1) and myocardial infarction (n = 3). The combined perioperative and 30-day minor complication rates were 2.7% and 1.4%, respectively. CONCLUSIONS: TCAR is a safe and effective method of carotid artery revascularization in a community hospital setting. This technology might help improve revascularization in patients without access to larger academic centers.
Subject(s)
Carotid Stenosis/therapy , Endovascular Procedures , Hospitals, Community , Aged , Carotid Stenosis/complications , Carotid Stenosis/diagnostic imaging , Carotid Stenosis/mortality , Embolic Protection Devices , Endovascular Procedures/adverse effects , Endovascular Procedures/instrumentation , Endovascular Procedures/mortality , Female , Humans , Male , Myocardial Infarction/etiology , Myocardial Infarction/mortality , Patient Safety , Retrospective Studies , Risk Assessment , Risk Factors , Stents , Stroke/etiology , Stroke/mortality , Time Factors , Treatment OutcomeABSTRACT
BACKGROUND: Preoperative carbohydrate loading is a recommended component of enhanced recovery protocols (ERP's), however the impact on postoperative stress-induced insulin resistance remains poorly studied in both diabetics and non-diabetics. METHODS: Using our ERP, a preoperative grape juice group (Grape) was compared to the use of 25â¯g maltodextrin/3â¯g citrulline (G.E.D.™, SOF Health, LLC) for carbohydrate loading. RESULTS: The population included 171 patients (Grape nâ¯=â¯96; GED nâ¯=â¯75). Glycemic variability was significantly worse for the Grape group on POD 0 in both non-diabetic (70% vs 41%; pâ¯<â¯0.05) and diabetic patients (66% vs 34%; pâ¯<â¯0.05). Significantly more Grape patients required postoperative insulin regardless of diabetic status. CONCLUSION: Following bariatric surgery, the impact of stress induced hyperglycemia is primarily on POD 0 in non-diabetics whereas the effect extends into POD 1 for diabetics. Preoperative loading with G.E.D.™ versus grape juice is associated with a significantly lower rate of glycemic variation and postoperative insulin requirement, demonstrating that drink composition and treatment process reduces the severity of postoperative stress induced hyperglycemia in bariatric surgery patients.
Subject(s)
Bariatric Surgery , Beverages , Diet, Carbohydrate Loading , Hyperglycemia/prevention & control , Postoperative Complications/prevention & control , Preoperative Care/methods , Stress, Physiological/drug effects , Adult , Citrulline , Diabetes Mellitus, Type 2/complications , Enhanced Recovery After Surgery , Female , Fruit and Vegetable Juices , Humans , Insulin Resistance , Male , Middle Aged , PolysaccharidesABSTRACT
The nascent polypeptide-associated complex (NAC) is a conserved ribosome-associated protein biogenesis factor. Whether NAC exerts chaperone activity and whether this function is restricted to de novo protein synthesis is unknown. Here, we demonstrate that NAC directly exerts chaperone activity toward structurally diverse model substrates including polyglutamine (PolyQ) proteins, firefly luciferase, and Aß40. Strikingly, we identified the positively charged ribosome-binding domain in the N terminus of the ßNAC subunit (N-ßNAC) as a major chaperone entity of NAC. N-ßNAC by itself suppressed aggregation of PolyQ-expanded proteins in vitro, and the positive charge of this domain was critical for this activity. Moreover, we found that NAC also exerts a ribosome-independent chaperone function in vivo. Consistently, we found that a substantial fraction of NAC is non-ribosomal bound in higher eukaryotes. In sum, NAC is a potent suppressor of aggregation and proteotoxicity of mutant PolyQ-expanded proteins associated with human diseases like Huntington's disease and spinocerebellar ataxias.
Subject(s)
Amyloid beta-Peptides/genetics , Molecular Chaperones/genetics , Protein Aggregation, Pathological/genetics , Amyloid beta-Peptides/chemistry , Binding Sites/genetics , Humans , Huntington Disease/genetics , Huntington Disease/pathology , Luciferases/chemistry , Luciferases/genetics , Molecular Chaperones/chemistry , Peptides/chemistry , Peptides/genetics , Protein Binding/genetics , Protein Biosynthesis/genetics , Protein Domains/genetics , Protein Folding , Ribosomes/genetics , Spinocerebellar Ataxias/genetics , Spinocerebellar Ataxias/pathologyABSTRACT
Stimulator of interferons genes (STING) is an adaptor protein that plays a critical role in the secretion of type I interferons and pro-inflammatory cytokines in response to cytosolic nucleic acid. Recent research indicates the involvement of the STING pathway in uncontrolled inflammation, sepsis, and shock. STING signaling is significantly up-regulated in human sepsis, and STING agonists are suggested to contribute to the pathogenesis of sepsis and shock. Nevertheless, little is known about the consequences of activated STING-mediated signaling during sepsis. It has been shown that aberrant activation of the STING-dependent way can result in increased inflammation, type I interferons responses, and cell death (including apoptosis, necroptosis, and pyroptosis). In addition, autophagy modulation has been demonstrated to protect against multiple organs injuries in animal sepsis model. However, impaired autophagy may contribute to the aberrant activation of STING signaling, leading to uncontrolled inflammation and cell death. Here we present a comprehensive review of recent advances in the understanding of STING signaling, focusing on the regulatory mechanisms and the roles of this pathway in sepsis.
Subject(s)
Autophagy/physiology , Cell Death/physiology , Inflammation/metabolism , Interferons/metabolism , Sepsis/metabolism , Animals , Humans , Signal Transduction/physiologyABSTRACT
Amyloid diseases represent a growing social and economic burden in the developed world. Understanding the assembly pathway and the inhibition of amyloid formation is key to developing therapies to treat these diseases. The neurodegenerative condition Machado-Joseph disease is characterised by the self-aggregation of the protein ataxin-3. Ataxin-3 consists of a globular N-terminal Josephin domain, which can aggregate into curvilinear protofibrils, and an unstructured, dynamically disordered C-terminal domain containing three ubiquitin interacting motifs separated by a polyglutamine stretch. Upon expansion of the polyglutamine region above 50 residues, ataxin-3 undergoes a second stage of aggregation in which long, straight amyloid fibrils form. A peptide inhibitor of polyglutamine aggregation, known as polyQ binding peptide 1, has been shown previously to prevent the maturation of ataxin-3 fibrils. However, the mechanism of this inhibition remains unclear. Using nanoelectrospray ionisation-mass spectrometry, we demonstrate that polyQ binding peptide 1 binds to monomeric ataxin-3. By investigating the ability of polyQ binding peptide 1 to bind to truncated ataxin-3 constructs lacking one or more domains, we localise the site of this interaction to a 39-residue sequence immediately C-terminal to the Josephin domain. The results suggest a new mechanism for the inhibition of polyglutamine aggregation by polyQ binding peptide 1 in which binding to a region outside of the polyglutamine tract can prevent fibril formation, highlighting the importance of polyglutamine flanking regions in controlling aggregation and disease.
Subject(s)
Amyloid/chemistry , Amyloid/metabolism , Ataxin-3/chemistry , Ataxin-3/metabolism , Peptides/metabolism , Binding Sites , Humans , Machado-Joseph Disease/diagnosis , Machado-Joseph Disease/metabolism , Mass Spectrometry , Peptides/chemistry , Protein BindingABSTRACT
Bayesian hypothesis testing presents an attractive alternative to p value hypothesis testing. Part I of this series outlined several advantages of Bayesian hypothesis testing, including the ability to quantify evidence and the ability to monitor and update this evidence as data come in, without the need to know the intention with which the data were collected. Despite these and other practical advantages, Bayesian hypothesis tests are still reported relatively rarely. An important impediment to the widespread adoption of Bayesian tests is arguably the lack of user-friendly software for the run-of-the-mill statistical problems that confront psychologists for the analysis of almost every experiment: the t-test, ANOVA, correlation, regression, and contingency tables. In Part II of this series we introduce JASP ( http://www.jasp-stats.org ), an open-source, cross-platform, user-friendly graphical software package that allows users to carry out Bayesian hypothesis tests for standard statistical problems. JASP is based in part on the Bayesian analyses implemented in Morey and Rouder's BayesFactor package for R. Armed with JASP, the practical advantages of Bayesian hypothesis testing are only a mouse click away.
Subject(s)
Bayes Theorem , Psychology , Software , Humans , Research DesignABSTRACT
Divalent metal-ion transporter-1 (DMT1), the principal mechanism by which nonheme iron is taken up at the intestinal brush border, is energized by the H(+)-electrochemical potential gradient. The provenance of the H(+) gradient in vivo is unknown, so we have explored a role for brush-border Na(+)/H(+) exchanger (NHE) isoforms by examining iron homeostasis and intestinal iron handling in mice lacking NHE2 or NHE3. We observed modestly depleted liver iron stores in NHE2-null (NHE2(-/-)) mice stressed on a low-iron diet but no change in hematological or blood iron variables or the expression of genes associated with iron metabolism compared with wild-type mice. Ablation of NHE3 strongly depleted liver iron stores, regardless of diet. We observed decreases in blood iron variables but no overt anemia in NHE3-null (NHE3(-/-)) mice on a low-iron diet. Intestinal expression of DMT1, the apical surface ferrireductase cytochrome b reductase-1, and the basolateral iron exporter ferroportin was upregulated in NHE3(-/-) mice, and expression of liver Hamp1 (hepcidin) was suppressed compared with wild-type mice. Absorption of (59)Fe from an oral dose was substantially impaired in NHE3(-/-) compared with wild-type mice. Our data point to an important role for NHE3 in generating the H(+) gradient that drives DMT1-mediated iron uptake at the intestinal brush border.
Subject(s)
Gene Expression Regulation/physiology , Iron/metabolism , Microvilli/physiology , Sodium-Hydrogen Exchangers/metabolism , Animals , Biological Transport , Humans , Intestinal Mucosa/metabolism , Mice , Mice, Knockout , Oocytes , Sodium/metabolism , Sodium-Hydrogen Exchanger 3 , Sodium-Hydrogen Exchangers/genetics , Transcription Factors/genetics , Transcription Factors/metabolism , Water-Electrolyte Imbalance , XenopusABSTRACT
In Alzheimer's disease (AD), the accumulation and deposition of amyloid-ß (Aß) peptides in the brain is a central event. Aß is cleaved from amyloid precursor protein (APP) by ß-secretase and γ-secretase mainly in neurons. Although mutations inAPP,PS1, orPS2cause early-onset familial AD,ABCA7encoding ATP-binding cassette transporter A7 is one of the susceptibility genes for late-onset AD (LOAD), in which itsloss-of-functionvariants increase the disease risk. ABCA7 is homologous to a major lipid transporter ABCA1 and is highly expressed in neurons and microglia in the brain. Here, we show that ABCA7 deficiency altered brain lipid profile and impaired memory in ABCA7 knock-out (Abca7(-/-)) mice. When bred to amyloid model APP/PS1 mice, plaque burden was exacerbated by ABCA7 deficit.In vivomicrodialysis studies indicated that the clearance rate of Aß was unaltered. Interestingly, ABCA7 deletion facilitated the processing of APP to Aß by increasing the levels of ß-site APP cleaving enzyme 1 (BACE1) and sterol regulatory element-binding protein 2 (SREBP2) in primary neurons and mouse brains. Knock-down of ABCA7 expression in neurons caused endoplasmic reticulum stress highlighted by increased level of protein kinase R-like endoplasmic reticulum kinase (PERK) and increased phosphorylation of eukaryotic initiation factor 2α (eIF2α). In the brains of APP/PS1;Abca7(-/-)mice, the level of phosphorylated extracellular regulated kinase (ERK) was also significantly elevated. Together, our results reveal novel pathways underlying the association of ABCA7 dysfunction and LOAD pathogenesis. SIGNIFICANCE STATEMENT: Gene variants inABCA7encoding ATP-binding cassette transporter A7 are associated with the increased risk for late-onset Alzheimer's disease (AD). Importantly, we found the altered brain lipid profile and impaired memory in ABCA7 knock-out mice. The accumulation of amyloid-ß (Aß) peptides cleaved from amyloid precursor protein (APP) in the brain is a key event in AD pathogenesis and we also found that ABCA7 deficit exacerbated brain Aß deposition in amyloid AD model APP/PS1 mice. Mechanistically, we found that ABCA7 deletion facilitated the processing of APP and Aß production by increasing the levels of ß-secretase 1 (BACE1) in primary neurons and mouse brains without affecting the Aß clearance rate in APP/PS1 mice. Our study demonstrates a novel mechanism underlying how dysfunctions of ABCA7 contribute to the risk for AD.
Subject(s)
ATP-Binding Cassette Transporters/deficiency , Alzheimer Disease , Amyloid beta-Peptides/metabolism , Brain/metabolism , Gene Expression Regulation/genetics , ATP-Binding Cassette Transporters/genetics , ATP-Binding Cassette Transporters/metabolism , Alzheimer Disease/genetics , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amyloid beta-Protein Precursor/genetics , Animals , Brain/pathology , Disease Models, Animal , Eukaryotic Initiation Factor-2/metabolism , Female , Humans , Lipid Metabolism/genetics , Male , Memory Disorders/genetics , Mice , Mice, Transgenic , Mutation/genetics , Presenilin-1/genetics , Signal Transduction/geneticsABSTRACT
Intrahospital transportation of critically ill patients is associated with significant complications. In order to reduce overall risk to the patient, such transports should well organized, efficient, and accompanied by the proper monitoring, equipment, and personnel. Protocols and guidelines for patient transfers should be utilized universally across all healthcare facilities. Care delivered during transport and at the site of diagnostic testing or procedure should be equivalent to the level of care provided in the originating environment. Here we review the most common problems encountered during transport in the hospital setting, including various associated adverse outcomes. Our objective is to make medical practitioners, nurses, and ancillary health care personnel more aware of the potential for various complications that may occur during patient movement from the intensive care unit to other locations within a healthcare facility, focusing on risk reduction and preventive strategies.
ABSTRACT
Atrazine, an herbicide used on most of the US corn (maize) crop, is the subject of ongoing controversy, with increasing documentation of its potentially harmful health and environmental impacts. Supporters of atrazine often claim that it is of great value to farmers; most recently, Syngenta, the producer of atrazine, sponsored an "Atrazine Benefits Team" (ABT) of researchers who released a set of five papers in 2011, reporting huge economic benefits from atrazine use in US agriculture. A critical review of the ABT papers shows that they have underestimated the growing problem of atrazine-resistant weeds, offered only a partial review of the effectiveness of alternative herbicides, and ignored the promising option of nonchemical weed management techniques. In addition, the most complete economic analysis in the ABT papers implies that withdrawal of atrazine would lead to a decrease in corn yields of 4.4% and an increase in corn prices of 8.0%. The result would be an increase in corn growers' revenues, equal to US$1.7 billion annually under ABT assumptions. Price impacts on consumers would be minimal: at current levels of ethanol production and use, gasoline prices would rise by no more than US$0.03 per gallon; beef prices would rise by an estimated US$0.01 for a 4-ounce hamburger and US$0.05 for an 8-ounce steak. Thus withdrawal of atrazine would boost farm revenues, while only changing consumer prices by pennies.
Subject(s)
Atrazine/analysis , Herbicides/analysis , Weed Control/methods , Zea mays/drug effects , Atrazine/economics , Environmental Policy , Government Regulation , Herbicides/economics , United States , Weed Control/economics , Weed Control/instrumentation , Zea mays/economicsABSTRACT
Divalent metal-ion transporter-1 (DMT1) is a widely expressed, iron-preferring membrane transport protein. Animal models establish that DMT1 plays indispensable roles in intestinal nonheme-iron absorption and iron acquisition by erythroid precursor cells. Rare mutations in human DMT1 result in severe microcytic-hypochromic anemia. When we express DMT1 in RNA-injected Xenopus oocytes, we observe rheogenic Fe(2+) transport that is driven by the proton electrochemical potential gradient. In that same preparation, DMT1 also transports cadmium and manganese but not copper. Whether manganese metabolism relies upon DMT1 remains unclear but DMT1 contributes to the effects of overexposure to cadmium and manganese in some tissues. There exist at least four DMT1 isoforms that arise from variant transcription of the SLC11A2 gene. Whereas these isoforms display identical functional properties, N- and C-terminal variations contain cues that direct the cell-specific targeting of DMT1 isoforms to discrete subcellular compartments (plasma membrane, endosomes, and lysosomes). An iron-responsive element (IRE) in the mRNA 3'-untranslated region permits the regulation of some isoforms by iron status, and additional mechanisms by which DMT1 is regulated are emerging. Natural-resistance-associated macrophage protein-1 (NRAMP1)-the only other member of the mammalian SLC11 gene family-contributes to antimicrobial function by extruding from the phagolysosome divalent metal ions (e.g. Mn(2+)) that may be essential cofactors for bacteria-derived enzymes or required for bacterial growth. The principal or only intestinal nonheme-iron transporter, DMT1 is a validated therapeutic target in hereditary hemochromatosis (HHC) and other iron-overload disorders.