Sugar Habit Hacker: Initial evidence that a planning intervention reduces sugar intake.

BACKGROUND AND AIMS: Sugar is a potentially addictive substance that is consumed in such high levels the World Health Organisation has set recommended consumption limits. To date there are no empirically tested brief interventions for reducing sugar consumption in adult populations. The current study aimed to preliminarily assess the feasibility of recruitment, retention, and intervention engagement and impact of a brief intervention. METHODS: This pre-post study recruited 128 adults from New Zealand to complete a 30-day internet-delivered intervention with in-person and email coaching. The intervention components were derived from implementation intention principles whereby the gap between intention and behaviour was targeted. Participants selected sugar consumption goals aligned with WHO recommendations by gender. To meet these goals, participants developed action plans and coping plans and engaged in self-monitoring. Facilitation was provided by a coach to maintain retention and treatment adherence over the 30 days. RESULTS: Intervention materials were rated as very useful and participants were mostly satisfied with the program. The total median amount of sugar consumed at baseline was 1,662.5 g (396 teaspoons per week) which was reduced to 362.5 g (86 teaspoons) at post-intervention evaluation (d = 0.83). The intervention was associated with large effects on reducing cravings (d = 0.59) and psychological distress (d = 0.68) and increasing situational self-efficacy (d = 0.92) and well-being (d = 0.68) with a reduction in BMI (d = 0.51). CONCLUSION: This feasibility study indicates that a brief intervention delivering goal setting, implementation planning, and self-monitoring may assist people to reduce sugar intake to within WHO recommendations.

I was truly addicted to sugar: A consumer-focused classification system of behaviour change strategies for sugar reduction.

The reduction of free sugars has been identified as a priority issue internationally. A range of public health initiatives have been recommended, including the provision of information and support for sugar reduction. To inform these approaches, it is important to know what people actually do in real world settings to reduce their consumption. This study documents and defines the range of consumer-based behaviour change strategies for sugar reduction. A total of 1145 strategies were extracted from 47 internet sources (i.e., consumer, popular and professional). Using a pragmatic content analysis, hundreds of strategies were organized into 25 discrete categories of strategies. Categories were grouped into the Rubicon Model of Action Phases and classified as pre-decisional (i.e., decisional balance, feedback, realisation, seek knowledge and information), post-decisional (i.e., action planning, coping planning, set goal intention, sugar guidelines) and actional phase. Actional strategies were the most prolific and included avoidance, consumption control, consumption planning, environmental restructuring, healthy eating focus, maintain readiness, professional support, refocusing, self-monitoring, social support, substance substitution, tapering, address underlying issues, urge management, well-being and withdrawal management. There was one post-actional strategy which was associated with self-evaluation (i.e., reviewing a change attempt in order to plan for the future). Four categories of strategies differed according to the source. Substance substitution was substantially less frequently discussed by consumers than professionals and few professional sites acknowledged or advised strategies to manage the struggle of maintaining readiness following a change attempt. Hundreds of individual strategies are discussed or promoted in online settings, and more information is needed on the effectiveness of these self-initiated approaches.

Development of a hydrogen cyanide inhalation exposure system and determination of the inhaled median lethal dose in the swine model.

OBJECTIVE: Cyanide is a highly toxic chemical, and acute exposure depletes cells and tissue of oxygen, depressing the respiratory, cardiovascular and neurological systems and potentially leading to death. Cyanide has been used as a weapon since ancient Rome and continues to pose a potential threat today. A well-characterized animal model is necessary for the development of novel methods of rapid detection and treatment. This manuscript describes the development of an inhalation exposure system designed to evaluate the lethality of acute cyanide inhalation in the porcine model. MATERIALS AND METHODS: A custom designed hydrogen cyanide (HCN) inhalation exposure system provided stable cyanide concentrations to un-anesthetized swine while monitoring respiratory parameters. Real-time respiratory monitoring, cyanide concentration and body weight were used to calculate inhaled doses. RESULTS: The inhalation exposure system generated controlled HCN ranging from 260 to 986 ppm to achieve inhaled doses between 1.78 and 3.97 mg/kg. Based on survival outcomes, the median lethal dose was determined to be 2.21 mg/kg, and the median lethal exposure level was 5893 mg min/m3. DISCUSSION: The ability of the HCN inhalation exposure system to deliver target inhaled doses and the determination of the inhaled median lethal dose in swine support the use of the exposure system and animal model for the evaluation of medical countermeasures of acute inhaled HCN toxicity.

Sodium Nitrite and Sodium Thiosulfate Are Effective Against Acute Cyanide Poisoning When Administered by Intramuscular Injection.

STUDY OBJECTIVE: The 2 antidotes for acute cyanide poisoning in the United States must be administered by intravenous injection. In the out-of-hospital setting, intravenous injection is not practical, particularly for mass casualties, and intramuscular injection would be preferred. The purpose of this study is to determine whether sodium nitrite and sodium thiosulfate are effective cyanide antidotes when administered by intramuscular injection. METHODS: We used a randomized, nonblinded, parallel-group study design in 3 mammalian models: cyanide gas inhalation in mice, with treatment postexposure; intravenous sodium cyanide infusion in rabbits, with severe hypotension as the trigger for treatment; and intravenous potassium cyanide infusion in pigs, with apnea as the trigger for treatment. The drugs were administered by intramuscular injection, and all 3 models were lethal in the absence of therapy. RESULTS: We found that sodium nitrite and sodium thiosulfate individually rescued 100% of the mice, and that the combination of the 2 drugs rescued 73% of the rabbits and 80% of the pigs. In all 3 species, survival in treated animals was significantly better than in control animals (log rank test, P<.05). In the pigs, the drugs attenuated an increase in the plasma lactate concentration within 5 minutes postantidote injection (difference: plasma lactate, saline solution-treated versus nitrite- or thiosulfate-treated 1.76 [95% confidence interval 1.25 to 2.27]). CONCLUSION: We conclude that sodium nitrite and sodium thiosulfate administered by intramuscular injection are effective against severe cyanide poisoning in 3 clinically relevant animal models of out-of-hospital emergency care.

Efficacy of Recommended Prehospital Human Equivalent Doses of Atropine and Pralidoxime Against the Toxic Effects of Carbamate Poisoning in the Hartley Guinea Pig.

PURPOSE: Aldicarb and methomyl are carbamate pesticides commonly implicated in human poisonings. The primary toxic mechanism of action for carbamate poisoning is cholinesterase (ChE) inhibition. As such, it is logical to assume that the currently accepted therapies for organophosphate poisoning (muscarinic antagonist atropine and the oxime acetylcholinesterase reactivator pralidoxime chloride [2-PAM Cl]) could afford therapeutic protection. However, oximes have been shown to be contraindicated for poisoning by some carbamates. METHODS: A protective ratio study was conducted in guinea pigs to evaluate the efficacy of atropine and 2-PAM Cl. The ChE activity was determined in both the blood and the cerebral cortex. RESULTS: Coadministration of atropine free base (0.4 mg/kg) and 2-PAM Cl (25.7 mg/kg) demonstrated protective ratios of 2 and 3 against aldicarb and methomyl, respectively, relative to saline. The data reported here show that this protection was primarily mediated by the action of atropine. The reactivator 2-PAM Cl had neither positive nor negative effects on survival. Both blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were significantly reduced at 15 minutes postchallenge but gradually returned to normal within 24 hours. Analysis of cerebral cortex showed that BChE, but not AChE, activity was reduced in animals that succumbed prior to 24 hours after challenge. CONCLUSION: The results suggest that coadministration of atropine and 2-PAM Cl at the currently recommended human equivalent doses for use in the prehospital setting to treat organophosphorus nerve agent and pesticide poisoning would likely also be effective against aldicarb or methomyl poisoning.

High performance liquid chromatography tandem mass spectrometry assay for the determination of cobinamide in pig plasma.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been widely utilized for the analysis of compounds in biological matrices due to its selectivity and sensitivity. This study describes the application of an LC-MS/MS-based approach toward the analysis of cobinamide in Yorkshire pig plasma. The selectivity, accuracy, precision, recovery, linearity, range, carryover, sensitivity, matrix effect, interference, stability, reproducibility, and ruggedness of the method were investigated in pig plasma. The accuracy and precision of the method was determined to be within 10% over three different days over a range of concentrations (25-10,000ng/mL) that spanned more than two orders of magnitude. The lower limit of quantitation (LLOQ) for dicyanocobinamide was determined to be 25ng/mL in pig plasma. Carryover was acceptable, as the area response of the carryover blanks were ≤15% of the area response of the nearest LLOQ standard for the analyte, while it was nonexistent for the internal standard. Specificity was ensured using six different lots of pig plasma. While the matrix effects of dicyanocobinamide in plasma were enhanced, ginsenoside Rb1 experienced signal suppression under the described conditions. The absolute recovery results for both compounds were consistent, precise, and reproducibly lower than expected at ∼60% for dicyanocobinamide and ∼22% for ginsenoside Rb1, confirming that a matrix standard curve was required for accurate quantitation. Cobinamide was shown to be very stable in matrix at various storage conditions including room temperature, refrigerated, and frozen at time intervals of 20h, 4 days, and 60 days respectively. This method was demonstrated to be sensitive, reproducible, stable, and rugged, and it should be applicable to the analysis of cobinamide in other biological matrices and species.

QuEChERS-based approach toward the analysis of two insecticides, methomyl and aldicarb, in blood and brain tissue.

QuEChERS has been widely utilized for the analysis of pesticides in produce, but it has not been as widely used in clinical test specimens, especially for smaller, sub-gram sample sizes. This study describes the application of a miniaturized QuEChERS methodology toward the analysis of two insecticides, methomyl and aldicarb, in guinea pig blood and brain tissue. Matrix effects and absolute recoveries were investigated for both analytes in the two matrices. While the matrix effects of methomyl in both matrices were minimal at most levels (i.e., from -20% to 20%), aldicarb experienced signal suppression under the described conditions (mean of -47%). However, the matrix effects were not cause for concern due to the sensitivity of the method and the use of matrix-matched standards. The precision and accuracy of the method were excellent over a range of concentrations that spanned three orders of magnitude. The limits of detection (LOD) for both carbamates were determined to be 0.1 ng mL-1 in blood and 0.2 ng g-1 in brain. Other validation parameters, such as linearity, accuracy, precision, and recovery, were also satisfactory in the blood and brain tissue. This method was demonstrated to be sensitive and reproducible, and it should be applicable to the analysis of a wide range of compounds of interest in sub-gram- and sub-milliliter-sized clinical and toxicology specimens.

Evaluation of HemogloBind™ treatment for preparation of samples for cholinesterase analysis.

Acetylcholine is an essential neurotransmitter found throughout the nervous system. Its action on postsynaptic receptors is regulated through hydrolysis by various carboxylesterases, especially cholinesterases (ChEs). The acute toxicity of organophosphate (OP) compounds is directly linked to their action as inhibitors of ChE. One widely used assay for evaluating ChE activity is a spectrophotometric method developed by Ellman et al. When the enzyme source is from tissues or, in particular, blood, hemoglobin displays a spectrophotometric peak at the same wavelength used to analyze cholinergic activity. This creates a substantial background that interferes with the Ellman's assay and must be overcome in order to accurately monitor cholinesterase activity. Herein, we directly compare blood processing methods: classical method (1.67 ± 0.30 U/mL) and HemogloBind™ treatment (1.51 ± 0.17 U/mL), and clearly demonstrate that pretreatment of blood samples with Hemoglobind™ is both a sufficient and rapid sample preparation method for the assessment of ChE activity using the Ellman's method.

Ifenprodil, a NR2B-selective antagonist of NMDA receptor, inhibits reverse Na+/Ca2+ exchanger in neurons.

Glutamate-induced delayed calcium dysregulation (DCD) is causally linked to excitotoxic neuronal death. The mechanisms of DCD are not completely understood, but it has been proposed that the excessive influx of external Ca(2+) is essential for DCD. The NMDA-subtype of glutamate receptor (NMDAR) and the plasmalemmal Na(+)/Ca(2+) exchanger operating in the reverse mode (NCX(rev)) have been implicated in DCD. In experiments with "younger" neurons, 6-8 days in vitro (6-8 DIV), in which the NR2A-containing NMDAR expression is low, ifenprodil, an inhibitor of NR2B-containing NMDAR, completely prevented DCD whereas PEAQX, another NMDAR antagonist that preferentially interacts with NR2A-NMDAR, was without effect. With "older" neurons (13-16 DIV), in which NR2A- and NR2B-NMDARs are expressed to a greater extent, both ifenprodil and PEAQX applied separately failed to prevent DCD. However, combined application of ifenprodil and PEAQX completely averted DCD. Ifenprodil and ifenprodil-like NR2B-NMDAR antagonists Ro 25-6981 and Co 101244 but not PEAQX or AP-5 inhibited gramicidin- and Na(+)/NMDG-replacement-induced increases in cytosolic Ca(2+) mediated predominantly by NCX(rev). This suggests that ifenprodil, Ro 25-6981, and Co 101244 inhibit NCX(rev). The ability of ifenprodil to inhibit NCX(rev) correlates with its efficacy in preventing DCD and emphasizes an important role of NCX(rev) in DCD. Overall our data suggest that both NR2A- and NR2B-NMDARs are involved in DCD in "older" neurons, and it is necessary to inhibit both NMDARs and NCX(rev) to prevent glutamate-induced DCD.

Delayed calcium dysregulation in neurons requires both the NMDA receptor and the reverse Na+/Ca2+ exchanger.

Glutamate-induced delayed calcium dysregulation (DCD) is a causal factor leading to neuronal death. The mechanism of DCD is not clear but Ca2+ influx via N-methyl-d-aspartate receptors (NMDAR) and/or the reverse plasmalemmal Na+/Ca2+ exchanger (NCXrev) could be involved in DCD. However, the extent to which NMDAR and NCX(rev) contribute to glutamate-induced DCD is uncertain. Here, we show that both NMDAR and NCX(rev) are critical for DCD in neurons exposed to excitotoxic glutamate. In rat cultured hippocampal neurons, 25 µM glutamate produced DCD accompanied by sustained increase in cytosolic Na+ ([Na+]c) and plasma membrane depolarization. MK801 and memantine, noncompetitive NMDAR inhibitors, added shortly after glutamate, completely prevented DCD whereas AP-5, a competitive NMDAR inhibitor, failed to protect against DCD. None of the tested inhibitors lowered elevated [Na+]c or restored plasma membrane potential. In the experiments with NCX reversal by gramicidin, MK801 and memantine robustly inhibited NCXrev while AP-5 was much less efficacious. In electrophysiological patch-clamp experiments MK801 and memantine inhibited NCXrev-mediated ion currents whereas AP-5 failed. Thus, MK801 and memantine, in addition to NMDAR, inhibited NCXrev. Inhibition of NCXrev either with KB-R7943, or by collapsing Na+ gradient across the plasma membrane, or by inhibiting Na+/H+ exchanger with 5-(N-ethyl-N-isopropyl) amiloride (EIPA) and thus preventing the increase in [Na+]c failed to preclude DCD. However, NCXrev inhibition combined with NMDAR blockade by AP-5 completely prevented DCD. Overall, our data suggest that both NMDAR and NCXrev are essential for DCD in glutamate-exposed neurons and inhibition of individual mechanism is not sufficient to prevent calcium dysregulation.

KB-R7943, an inhibitor of the reverse Na+ /Ca2+ exchanger, blocks N-methyl-D-aspartate receptor and inhibits mitochondrial complex I.

BACKGROUND AND PURPOSE: An isothiourea derivative (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methane sulfonate (KB-R7943), a widely used inhibitor of the reverse Na(+) /Ca(2+) exchanger (NCX(rev)), was instrumental in establishing the role of NCX(rev) in glutamate-induced Ca(2+) deregulation in neurons. Here, the effects of KB-R7943 on N-methyl-D-aspartate (NMDA) receptors and mitochondrial complex I were tested. EXPERIMENTAL APPROACH: Fluorescence microscopy, electrophysiological patch-clamp techniques and cellular respirometry with Seahorse XF24 analyzer were used with cultured hippocampal neurons; membrane potential imaging, respirometry and Ca(2+) flux measurements were made in isolated rat brain mitochondria. KEY RESULTS KB-R7943 inhibited NCX(rev) with IC(50) = 5.7 ± 2.1 µM, blocked NMDAR-mediated ion currents, and inhibited NMDA-induced increase in cytosolic Ca(2+) with IC(50) = 13.4 ± 3.6 µM but accelerated calcium deregulation and mitochondrial depolarization in glutamate-treated neurons. KB-R7943 depolarized mitochondria in a Ca(2+) -independent manner. Stimulation of NMDA receptors caused NAD(P)H oxidation that was coupled or uncoupled from ATP synthesis depending on the presence of Ca(2+) in the bath solution. KB-R7943, or rotenone, increased NAD(P)H autofluorescence under resting conditions and suppressed NAD(P)H oxidation following glutamate application. KB-R7943 inhibited 2,4-dinitrophenol-stimulated respiration of cultured neurons with IC(50) = 11.4 ± 2.4 µM. With isolated brain mitochondria, KB-R7943 inhibited respiration, depolarized organelles and suppressed Ca(2+) uptake when mitochondria oxidized complex I substrates but was ineffective when mitochondria were supplied with succinate, a complex II substrate. CONCLUSIONS AND IMPLICATIONS: KB-R7943, in addition to NCX(rev) , blocked NMDA receptors in cultured hippocampal neurons and inhibited complex I in the mitochondrial respiratory chain. These findings are critical for the correct interpretation of experimental results obtained with KB-R7943 and a better understanding of its neuroprotective action.