Therapeutic Anticoagulation with Heparin in Noncritically Ill Patients with Covid-19.

BACKGROUND: Thrombosis and inflammation may contribute to the risk of death and complications among patients with coronavirus disease 2019 (Covid-19). We hypothesized that therapeutic-dose anticoagulation may improve outcomes in noncritically ill patients who are hospitalized with Covid-19. METHODS: In this open-label, adaptive, multiplatform, controlled trial, we randomly assigned patients who were hospitalized with Covid-19 and who were not critically ill (which was defined as an absence of critical care-level organ support at enrollment) to receive pragmatically defined regimens of either therapeutic-dose anticoagulation with heparin or usual-care pharmacologic thromboprophylaxis. The primary outcome was organ support-free days, evaluated on an ordinal scale that combined in-hospital death (assigned a value of -1) and the number of days free of cardiovascular or respiratory organ support up to day 21 among patients who survived to hospital discharge. This outcome was evaluated with the use of a Bayesian statistical model for all patients and according to the baseline d-dimer level. RESULTS: The trial was stopped when prespecified criteria for the superiority of therapeutic-dose anticoagulation were met. Among 2219 patients in the final analysis, the probability that therapeutic-dose anticoagulation increased organ support-free days as compared with usual-care thromboprophylaxis was 98.6% (adjusted odds ratio, 1.27; 95% credible interval, 1.03 to 1.58). The adjusted absolute between-group difference in survival until hospital discharge without organ support favoring therapeutic-dose anticoagulation was 4.0 percentage points (95% credible interval, 0.5 to 7.2). The final probability of the superiority of therapeutic-dose anticoagulation over usual-care thromboprophylaxis was 97.3% in the high d-dimer cohort, 92.9% in the low d-dimer cohort, and 97.3% in the unknown d-dimer cohort. Major bleeding occurred in 1.9% of the patients receiving therapeutic-dose anticoagulation and in 0.9% of those receiving thromboprophylaxis. CONCLUSIONS: In noncritically ill patients with Covid-19, an initial strategy of therapeutic-dose anticoagulation with heparin increased the probability of survival to hospital discharge with reduced use of cardiovascular or respiratory organ support as compared with usual-care thromboprophylaxis. (ATTACC, ACTIV-4a, and REMAP-CAP ClinicalTrials.gov numbers, NCT04372589, NCT04505774, NCT04359277, and NCT02735707.).

Dietary Sodium Intake and Outcomes: a Secondary Analysis From Sodium-HF.

OBJECTIVES: This post hoc analysis of SODIUM-HF (Study of Dietary Intervention under 100 mmol in Heart Failure) assessed the association between baseline dietary sodium intake and change at 6 months with a composite of cardiovascular (CV) hospitalizations, emergency department visits and all-cause death at 12 and 24 months. BACKGROUND: Dietary sodium restriction is common advice for patients with heart failure (HF). Randomized clinical trials have not shown a beneficial effect of dietary sodium restriction on clinical outcomes. METHODS: A multivariable Cox proportional hazard regression model was used to assess the association of dietary sodium intake measured at randomization with primary and secondary endpoints. RESULTS: The study included 792 participants. Baseline sodium intake was ≤ 1500 mg/day in 19.9% (n = 158), 1501-3000 mg/day in 56.5% (n = 448) and > 3000 mg/day in 23.4% (n = 186) of participants. The factors associated with higher baseline sodium intake were higher calorie consumption, higher body mass index and recruitment from Canada. Multivariable analyses showed no association between baseline sodium intake nor magnitude of 6-month change or 12- or 24-month outcomes. In a responder analysis, participants achieving a sodium intake < 1500 mg at 6 months showed an association with a decreased risk for the composite outcome (adjusted HR 0.52 [95% CI 0.25, 1.07] P = 0.08) and CV hospitalization (adjusted HR 0.51 [95% CI 0.24, 1.09] P = 0.08) at 12 months. CONCLUSION: There was no association between dietary sodium intake and clinical outcomes over 24 months in patients with HF. Responder analyses suggest the need for further investigation of the effects of sodium reduction in those who achieve the targeted dietary sodium-reduction level.

Environment driven changes in type 2 diabetes, overweight and obesity in an isolated Mixe community in the Valley of Oaxaca, southern Mexico.

BACKGROUND: This study focused on type 2 diabetes mellitus (T2DM) in a group of adult Mixe, an Indigenous population from Oaxaca, Mexico. Mixe comprised an estimated 9.4% (n ≅ 90 000) of the Indigenous population in Oaxaca. Mexico. OBJECTIVE: This study focused on a group of adult Mixe, an Indigenous population from Oaxaca, Mexico. To compare the prevalence of T2DM, overweight (OW), obesity (OB), and hypertension (HTN) between 2007 and 2017 for a small, isolated Mixe community in the Valley of Oaxaca, Mexico. We test whether or not environmental changes have affected T2DM prevalence. METHODS AND MATERIALS: Demographic and medical record data were collected in the community in 2007 and 2017 from the medical clinic and the mayor's office. T2DM was medically diagnosed among adults (>34 years old), in 2007 (n = 730) and in 2017 (n = 829). RESULTS: T2DM crude prevalence increased from 6.7% to 12.1% (p < .001) from 2007 to 2017. The mean age of the sample analyzed was 60.6 (SD = 9.7). Age-adjusted T2DM prevalence increased from 6.7% to 10.8% (p < .002). T2DM was 5.7%-5.5% among males (p < .53) and 7.1%-13.6% among females (p < .001). Sex-specific OW and OB simulation studies indicate females had 7% less OW in 2007, and males were unchanged compared with 2017. OB among males and females was significantly higher in 2017 compared with 2007 (increased by 15.2% and 8.3%, males and females, respectively). Sexes combined OW + OB increased 12.7% among males but was unchanged in females (-0.5%). In the sexes combined analysis, OW prevalence increased 12.7% to 27.1% (p < .001) and OB prevalence increased 10.7%-27.9% (p < .001) from 2007 to 2017. HTN did not change significantly from 2007 to 2017 (15.4% and 14.6%, respectively) (p = .63) in adults. Among T2DM individuals, the frequency of HTN was not significantly different in 2007 and 2017 (57.1% and 37%, respectively) (p = .65). Transition to a Western diet consisting of high-carbohydrate foods occurred at the same time as increased T2DM from 2007 to 2017, with a higher prevalence of T2DM noted among females in 2017. CONCLUSIONS: An increased prevalence of T2DM, OW, and OB but not HTN was observed in the Mixe community from 2007 to 2017 and was associated with the adoption of a high-carbohydrate Western diet.

Reduction of dietary sodium to less than 100 mmol in heart failure (SODIUM-HF): an international, open-label, randomised, controlled trial.

BACKGROUND: Dietary restriction of sodium has been suggested to prevent fluid overload and adverse outcomes for patients with heart failure. We designed the Study of Dietary Intervention under 100 mmol in Heart Failure (SODIUM-HF) to test whether or not a reduction in dietary sodium reduces the incidence of future clinical events. METHODS: SODIUM-HF is an international, open-label, randomised, controlled trial that enrolled patients at 26 sites in six countries (Australia, Canada, Chile, Colombia, Mexico, and New Zealand). Eligible patients were aged 18 years or older, with chronic heart failure (New York Heart Association [NYHA] functional class 2-3), and receiving optimally tolerated guideline-directed medical treatment. Patients were randomly assigned (1:1), using a standard number generator and varying block sizes of two, four, or six, stratified by site, to either usual care according to local guidelines or a low sodium diet of less than 100 mmol (ie, <1500 mg/day). The primary outcome was the composite of cardiovascular-related admission to hospital, cardiovascular-related emergency department visit, or all-cause death within 12 months in the intention-to-treat (ITT) population (ie, all randomly assigned patients). Safety was assessed in the ITT population. This study is registered with ClinicalTrials.gov, NCT02012179, and is closed to accrual. FINDINGS: Between March 24, 2014, and Dec 9, 2020, 806 patients were randomly assigned to a low sodium diet (n=397) or usual care (n=409). Median age was 67 years (IQR 58-74) and 268 (33%) were women and 538 (66%) were men. Between baseline and 12 months, the median sodium intake decreased from 2286 mg/day (IQR 1653-3005) to 1658 mg/day (1301-2189) in the low sodium group and from 2119 mg/day (1673-2804) to 2073 mg/day (1541-2900) in the usual care group. By 12 months, events comprising the primary outcome had occurred in 60 (15%) of 397 patients in the low sodium diet group and 70 (17%) of 409 in the usual care group (hazard ratio [HR] 0·89 [95% CI 0·63-1·26]; p=0·53). All-cause death occurred in 22 (6%) patients in the low sodium diet group and 17 (4%) in the usual care group (HR 1·38 [0·73-2·60]; p=0·32), cardiovascular-related hospitalisation occurred in 40 (10%) patients in the low sodium diet group and 51 (12%) patients in the usual care group (HR 0·82 [0·54-1·24]; p=0·36), and cardiovascular-related emergency department visits occurred in 17 (4%) patients in the low sodium diet group and 15 (4%) patients in the usual care group (HR 1·21 [0·60-2·41]; p=0·60). No safety events related to the study treatment were reported in either group. INTERPRETATION: In ambulatory patients with heart failure, a dietary intervention to reduce sodium intake did not reduce clinical events. FUNDING: Canadian Institutes of Health Research and the University Hospital Foundation, Edmonton, Alberta, Canada, and Health Research Council of New Zealand.

Hemoglobin and Clinical Outcomes in the Vericiguat Global Study in Patients With Heart Failure and Reduced Ejection Fraction (VICTORIA).

BACKGROUND: In the VICTORIA trial (Vericiguat Global Study in Patients with Heart Failure with Reduced Ejection Fraction), anemia occurred more often in patients treated with vericiguat (7.6%) than with placebo (5.7%). We explored the association between vericiguat, randomization hemoglobin, development of anemia, and whether the benefit of vericiguat related to baseline hemoglobin. METHODS: Anemia was defined as hemoglobin <13.0 g/dL in men and <12.0 g/dL in women (World Health Organization Anemia). Adverse events reported as anemia were also evaluated. We assessed the risk-adjusted relationship between hemoglobin and hematocrit with the primary outcome (composite of cardiovascular death or heart failure hospitalization) and the time-updated hemoglobin relationship to outcomes. RESULTS: At baseline, 1719 (35.7%) patients had World Health Organization anemia; median hemoglobin was 13.4 g/L (25th, 75th percentile: 12.1, 14.7 g/dL). At 16 weeks from randomization, 1643 patients had World Health Organization anemia (284 new for vericiguat and 219 for placebo), which occurred more often with vericiguat than placebo (P<0.001). After 16 weeks, no further decline in hemoglobin occurred over 96 weeks of follow-up and the ratio of hemoglobin/hematocrit remained constant. Overall, adverse event anemia occurred in 342 patients (7.1%). A lower hemoglobin was unrelated to the treatment benefit of vericiguat (versus placebo) on the primary outcome. In addition, analysis of time-updated hemoglobin revealed no association with the treatment effect of vericiguat (versus placebo) on the primary outcome. CONCLUSIONS: Anemia was common at randomization and lower hemoglobin was associated with a greater frequency of clinical events. Although vericiguat modestly lowered hemoglobin by 16 weeks, this effect did not further progress nor was it related to the treatment benefit of vericiguat. Registration: URL: https://www.clinicaltrials.gov: Unique identifier: NCT02861534.

Outcomes of Participants With Diabetes in the ISCHEMIA Trials.

BACKGROUND: Among patients with diabetes and chronic coronary disease, it is unclear if invasive management improves outcomes when added to medical therapy. METHODS: The ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) trials (ie, ISCHEMIA and ISCHEMIA-Chronic Kidney Disease) randomized chronic coronary disease patients to an invasive (medical therapy + angiography and revascularization if feasible) or a conservative approach (medical therapy alone with revascularization if medical therapy failed). Cohorts were combined after no trial-specific effects were observed. Diabetes was defined by history, hemoglobin A1c ≥6.5%, or use of glucose-lowering medication. The primary outcome was all-cause death or myocardial infarction (MI). Heterogeneity of effect of invasive management on death or MI was evaluated using a Bayesian approach to protect against random high or low estimates of treatment effect for patients with versus without diabetes and for diabetes subgroups of clinical (female sex and insulin use) and anatomic features (coronary artery disease severity or left ventricular function). RESULTS: Of 5900 participants with complete baseline data, the median age was 64 years (interquartile range, 57-70), 24% were female, and the median estimated glomerular filtration was 80 mL·min-1·1.73-2 (interquartile range, 64-95). Among the 2553 (43%) of participants with diabetes, the median percent hemoglobin A1c was 7% (interquartile range, 7-8), and 30% were insulin-treated. Participants with diabetes had a 49% increased hazard of death or MI (hazard ratio, 1.49 [95% CI, 1.31-1.70]; P<0.001). At median 3.1-year follow-up the adjusted event-free survival was 0.54 (95% bootstrapped CI, 0.48-0.60) and 0.66 (95% bootstrapped CI, 0.61-0.71) for patients with diabetes versus without diabetes, respectively, with a 12% (95% bootstrapped CI, 4%-20%) absolute decrease in event-free survival among participants with diabetes. Female and male patients with insulin-treated diabetes had an adjusted event-free survival of 0.52 (95% bootstrapped CI, 0.42-0.56) and 0.49 (95% bootstrapped CI, 0.42-0.56), respectively. There was no difference in death or MI between strategies for patients with diabetes versus without diabetes, or for clinical (female sex or insulin use) or anatomic features (coronary artery disease severity or left ventricular function) of patients with diabetes. CONCLUSIONS: Despite higher risk for death or MI, chronic coronary disease patients with diabetes did not derive incremental benefit from routine invasive management compared with initial medical therapy alone. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01471522.

Predictors of outcome in the ISCHEMIA-CKD trial: Anatomy versus ischemia.

BACKGROUND: The ISCHEMIA-CKD (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches-Chronic Kidney Disease) trial found no advantage to an invasive strategy compared to conservative management in reducing all-cause death or myocardial infarction (D/MI). However, the prognostic influence of angiographic coronary artery disease (CAD) burden and ischemia severity remains unknown in this population. We compared the relative impact of CAD extent and severity of myocardial ischemia on D/MI in patients with advanced chronic kidney disease (CKD). METHODS: Participants randomized to invasive management with available data on coronary angiography and stress testing were included. Extent of CAD was defined by the number of major epicardial vessels with ≥50% diameter stenosis by quantitative coronary angiography. Ischemia severity was assessed by site investigators as moderate or severe using trial definitions. The primary endpoint was D/MI. RESULTS: Of the 388 participants, 307 (79.1%) had complete coronary angiography and stress testing data. D/MI occurred in 104/307 participants (33.9%). Extent of CAD was associated with an increased risk of D/MI (P < .001), while ischemia severity was not (P = .249). These relationships persisted following multivariable adjustment. Using 0-vessel disease (VD) as reference, the adjusted hazard ratio (HR) for 1VD was 1.86, 95% confidence interval (CI) 0.94 to 3.68, P = .073; 2VD: HR 2.13, 95% CI 1.10 to 4.12, P = .025; 3VD: HR 4.00, 95% CI 2.06 to 7.76, P < .001. Using moderate ischemia as the reference, the HR for severe ischemia was 0.84, 95% CI 0.54 to 1.30, P = .427. CONCLUSION: Among ISCHEMIA-CKD participants randomized to the invasive strategy, extent of CAD predicted D/MI whereas severity of ischemia did not.

Assessment of human pancreas cancer tissue and precursor lesions via a fluorophore with inherent PDAC selectivity.

The current five-year survival rate of <5% for pancreatic ductal adenocarcinoma (PDAC) is compounded by late diagnosis, a lack of PDAC-specific intraoperative guidance to ensure complete resection, and the ineffectiveness of current therapies. Previously, utilizing compound 1, a fluorophore with inherent PDAC selectivity, PDAC was visualized both in vivo and ex vivo in a murine model. In the current study, human PDAC tissue is targeted. Compound 1 selectively stains ducts of the adenocarcinoma versus the surrounding stroma, enabling the imaging of PDAC in frozen tissue sections with high contrast. To enhance the potential of 1 for intraoperative applications, the ex vivo staining protocol was optimized for rapid margin assessment, with a final staining time of ~15 min. To measure diagnostic performance, the area under a receiver operating characteristic (ROC) curve was measured for the identification of ductal adenocarcinoma vs. stroma. The bright fluorescence contrast enabled quantitative determination of PDAC (or precancerous PanIN lesions) versus healthy pancreas tissue in human tissue array samples.

Anti-Thrombotic Therapy to Ameliorate Complications of COVID-19 (ATTACC): Study design and methodology for an international, adaptive Bayesian randomized controlled trial.

BACKGROUND: Mortality from COVID-19 is high among hospitalized patients and effective therapeutics are lacking. Hypercoagulability, thrombosis and hyperinflammation occur in COVID-19 and may contribute to severe complications. Therapeutic anticoagulation may improve clinical outcomes through anti-thrombotic, anti-inflammatory and anti-viral mechanisms. Our primary objective is to evaluate whether therapeutic-dose anticoagulation with low-molecular-weight heparin or unfractionated heparin prevents mechanical ventilation and/or death in patients hospitalized with COVID-19 compared to usual care. METHODS: An international, open-label, adaptive randomized controlled trial. Using a Bayesian framework, the trial will declare results as soon as pre-specified posterior probabilities for superiority, futility, or harm are reached. The trial uses response-adaptive randomization to maximize the probability that patients will receive the more beneficial treatment approach, as treatment effect information accumulates within the trial. By leveraging a common data safety monitoring board and pooling data with a second similar international Bayesian adaptive trial (REMAP-COVID anticoagulation domain), treatment efficacy and safety will be evaluated as efficiently as possible. The primary outcome is an ordinal endpoint with three possible outcomes based on the worst status of each patient through day 30: no requirement for invasive mechanical ventilation, invasive mechanical ventilation or death. CONCLUSION: Using an adaptive trial design, the Anti-Thrombotic Therapy To Ameliorate Complications of COVID-19 trial will establish whether therapeutic anticoagulation can reduce mortality and/or avoid the need for mechanical ventilation in patients hospitalized with COVID-19. Leveraging existing networks to recruit sites will increase enrollment and mitigate enrollment risk in sites with declining COVID-19 cases.

A Diselenide Turn-On Fluorescent Probe for the Detection of Thioredoxin Reductase.

We report the first diselenide-based probe for the selective detection of thioredoxin reductase (TrxR), an enzyme commonly overexpressed in melanomas. The probe design involves conjugation of a seminaphthorhodafluor dye with a diselenide moiety. TrxR reduces the diselenide bond, triggering a fluorescence turn-on response of the probe. Kinetic studies reveal favorable binding of the probe with TrxR with a Michaelis-Menten constant (Km ) of 15.89 µm. Computational docking simulations predict a greater binding affinity to the TrxR active site in comparison to its disulfide analogue. In vitro imaging studies further confirmed the diselenide probe exhibited improved signaling of TrxR activity compared to the disulfide analogue.

Altering Fundamental Trends in the Emission of Xanthene Dyes.

Fluorescent small molecules enable researchers and clinicians to visualize biological events in living cells, tissues, and organs in real time. Herein, the focus is on the structure and properties of the relatively rare benzo[ a]xanthenes that exhibit enhanced steric and electronic interactions due to their annulated structures. Three types of fluorophores were synthesized: (i) pH- and solvent-dependent seminaphthorhodafluors, (ii) pH- and solvent-independent seminaphthorhodafluors, and (iii) pH-independent but solvent-sensitive seminaphthorhodamines. The probes exhibited promising far-red to near-infrared (NIR) emission, large Stoke shifts, broad full width at half-maximum (fwhm), relatively high quantum yields, and utility in immunofluorescence staining. Deviation of the π-system from planarity due to changes in the fluorophore ionization state resulted in fluorescence properties that are atypical of common xanthene dyes.

In Situ Lysosomal Cysteine-Specific Targeting and Imaging during Dexamethasone-Induced Apoptosis.

Herein we utilize the similar though divergent nucleophilic properties of cysteine, homocysteine, and glutathione to achieve the selective detection of cysteine under mildly acidic conditions. This enables the specific in situ detection of lysosomal cysteine. Employing time-dependent fluorescent imaging of probe-labeled A549 cells, we demonstrate that dexamethasone-induced apoptosis is not dependent on lysosomal cysteine. This methodology can thus produce useful information about pathogenesis associated with cysteine and lysosomes.

The Methylenetetrahydrofolate Reductase C677T (rs1801133) and Apolipoprotein A5-1131T>C (rs662799) Polymorphisms, and Anemia Are Independent Risk Factors for Ischemic Stroke.

BACKGROUND: Although there is adequate knowledge as to the role of traditional cardiovascular risk factors on stroke incidence, knowledge of other risk factors, particularly genetic ones, is still incomplete. METHODS: To assess the participation of some polymorphisms, along with other modifiable risk factors, a case-control study was conducted. A total of 253 cases were identified in the emergency room of a general regional hospital, with a clinical trait of stroke confirmed by a skull computerized axial tomography scan. In the surgery ward, 253 controls were identified, gender and age (±5 years) matched. Biochemical parameters were measured, and 4 polymorphisms were genotyped by polymerase chain reaction, rs1801133 (methylenetetrahydrofolate reductase [MTHFR]), rs1498373 (dimethylarginine dimethylaminohydrolase type 1 [DDAH1]), rs662799 (apolipoprotein A5 [APOA5]), and rs1799983 (endothelial nitric oxide). Odds ratios were estimated to assess the strength of association, with 95% confidence intervals, both in a matched case-control analysis and in a conditional regression analysis. RESULTS: Cases had higher mean blood pressure and triglycerides and lower hemoglobin levels. Heterozygous and homozygous subjects to the rs1801133 variant of the MTHFR gene had a 3-fold higher risk of stroke. In the dominant model, those with the polymorphism rs662799 of the promoter region for APOA5 had twice the risk of stroke. Anemia increased the risk of stroke 4-fold. CONCLUSIONS: Polymorphisms of the genes MTHFR (rs1801133) and APOA5 (rs662799), as well as anemia, are independent risk factors for stroke in Mexicans, together with traditional cardiovascular risk factors such as high triglycerides and high blood pressure.

JBASE: Joint Bayesian Analysis of Subphenotypes and Epistasis.

MOTIVATION: Rapid advances in genotyping and genome-wide association studies have enabled the discovery of many new genotype-phenotype associations at the resolution of individual markers. However, these associations explain only a small proportion of theoretically estimated heritability of most diseases. In this work, we propose an integrative mixture model called JBASE: joint Bayesian analysis of subphenotypes and epistasis. JBASE explores two major reasons of missing heritability: interactions between genetic variants, a phenomenon known as epistasis and phenotypic heterogeneity, addressed via subphenotyping. RESULTS: Our extensive simulations in a wide range of scenarios repeatedly demonstrate that JBASE can identify true underlying subphenotypes, including their associated variants and their interactions, with high precision. In the presence of phenotypic heterogeneity, JBASE has higher Power and lower Type 1 Error than five state-of-the-art approaches. We applied our method to a sample of individuals from Mexico with Type 2 diabetes and discovered two novel epistatic modules, including two loci each, that define two subphenotypes characterized by differences in body mass index and waist-to-hip ratio. We successfully replicated these subphenotypes and epistatic modules in an independent dataset from Mexico genotyped with a different platform. AVAILABILITY AND IMPLEMENTATION: JBASE is implemented in C++, supported on Linux and is available at http://www.cs.toronto.edu/∼goldenberg/JBASE/jbase.tar.gz. The genotype data underlying this study are available upon approval by the ethics review board of the Medical Centre Siglo XXI. Please contact Dr Miguel Cruz at mcruzl@yahoo.com for assistance with the application. CONTACT: anna.goldenberg@utoronto.ca SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Systemic Delivery and Biodistribution of Cisplatin in Vivo.

Cisplatin is widely used to treat a variety of cancers. However, ototoxicity and nephrotoxicity remain serious side effects of cisplatin-based chemotherapy. In order to inform the study of cisplatin's off-target effects, a new drug-fluorophore conjugate was synthesized that exhibited utility as a tracer to determine the cellular uptake and in vivo distribution of cisplatin. This probe will serve as a useful tool to facilitate investigations into the kinetics and biodistribution of cisplatin and its associated side effects in preclinical models after systemic administration.

Recent progress in chromogenic and fluorogenic chemosensors for hypochlorous acid.

Due to the biological and industrial importance of hypochlorous acid, the development of optical probes for HOCl has been an active research area. Hypochlorous acid and hypochlorite can oxidize electron-rich analytes with accompanying changes in molecular sensor spectroscopic profiles. Probes for such processes may monitor HOCl levels in the environment or in an organism and via bio-labeling or bioimaging techniques. This review summarizes recent developments in the area of chromogenic and fluorogenic chemosensors for HOCl.

Fluorescein Tri-Aldehyde Promotes the Selective Detection of Homocysteine.

Elevated homocysteine levels are a well-known independent risk factor for cardiovascular disease. To date, relatively few selective fluorescent probes for homocysteine detection have been reported. The lack of sensing reagents and remaining challenges largely derive from issues of sensitivity and/or selectivity. For example, homocysteine is a structural homologue of the more abundant (ca, 20-25 fold) aminothiol cysteine, differing only by an additional methylene group side chain. Fluorescein tri-aldehyde, described herein, has been designed and synthesized as a sensitive and selective fluorophore for the detection of homocysteine in human plasma samples. It responds to analytes selectively via a photoinduced electron transfer (PET) inhibition process that is modulated by predictable analyte-dye product hybridization and ionization states. Mulliken population analysis of fluorescein tri-aldehyde and its reaction products reveals that the characteristic formation of multiple cationic of homocysteine-derived heterocycles leads to enhanced relative negative charge build up on the proximal phenolate oxygen of the fluorophore as a contributing factor to selective emission enhancement.

Rhodamine analogues for molecular ruler applications.

A series of geometrically well-defined cationic fluorophores were designed based on molecular mechanics. They contain biaryl linkers to impart rigidity preventing intramolecular folding between a conjugated biomolecule and fluorophore. All probes have absorption and emission maxima within 20 nm from Texas Red, as predicted by TDDFT calculations and validated experimentally.

A simple assay for glutathione in whole blood.

A method for detecting glutathione selectively in whole blood deposited on filter paper is described. GSH is fractionated from proteins, hemoglobin and other potentially interfering components and determined using a resorufin-acrylate fluorescent probe. The relative standard deviation is lower than 5% (n = 5). Recoveries of GSH from whole blood are between 94% and 108.6%.

Templated polymers enable selective capture and release of lysophosphatidic acid in human plasma via optimization of non-covalent binding to functional monomers.

The first solid phase extraction materials for selective lysophosphatidic acid (LPA) enrichment from human plasma are described. Molecularly imprinted polymers were designed, synthesized and evaluated as cartridge fillings. They enabled a relatively rapid and simple extraction protocol for LPA without any need for multiple liquid-liquid extraction steps. The five major subspecies of lysophosphatidic acid are readily separated from all other native plasma phospholipids, including those well-known to interfere with LPA quantitation, such as phosphatidylcholine and lysophosphatidylcholine. Outstanding LPA purity is obtained via these solid phase materials in a tandem extraction setup.