Antimalarial activity of vitamin D3 (VD3) does not result from VD3-induced antimicrobial agents including nitric oxide or cathelicidin.

Recent evidence suggests that 1α,25-dihydroxyvitamin D3 (VD3), the active form of vitamin D, inhibits microbial proliferation. Previously, we used in vivo murine models to investigate the antimalarial activity of VD3 and confirmed potent antimalarial activity in the acute phase. This study aimed to clarify the mechanisms underlying the antimalarial activity of VD3 in vivo, particularly extensive inhibition of parasitemia in the acute phase, focusing on nitric oxide (NO), a potent antimalarial molecule. VD3 is a good NO inducer. When most Plasmodium chabaudi AS (PcAS)-infected mice treated with VD3 survived, NO was present in blood samples obtained from VD3-treated mice at a significantly higher rate at 2 and/or 3 days post-infection than that in vehicle-treated control mice. To verify the involvement of NO in the antimalarial activity of VD3, we used aminoguanidine (AG), an inducible NO synthase (iNOS) inhibitor, to abrogate the antimalarial activity of VD3. However, despite AG-induced reductions in NO levels, parasitemia remained inhibited during the acute phase, even in the presence of AG, and the antiplasmodial faculty of VD3 was not ablated. VD3-mediated antimalarial activity irrelevant of NO compelled us to consider another candidate. In a pilot experiment, we used cathelicidin (CAMP), an antimicrobial peptide, since it is known that VD3 induces CAMP synthesis. Serum CAMP levels increased on days 4 or 5 post-infection with or without VD3 administration, but experiments using exogenous CAMP did not display curative effects in PcAS-infected mice. The present study using VD3 to target the malarial parasite thus suggests a potential novel approach to treat malarial infections.

Blood gas analysis in pigs submitted to different concentrations of nitrous oxide or oxygen, under different ventilatory modalities / Estudo hemogasométrico em suínos submetidos a diferentes concentrações de óxido nitroso ou oxigênio, sob diferentes modalidades ventilatórias

The effects of different concentrations of oxygen and nitrous oxide on blood gas parameters in pigs maintained under spontaneous or pressure-controlled ventilation, with or without positive end-expiratory pressure (PEEP), were compared. Forty-eight pigs were randomly divided into six groups, submitted to different concentrations of compressed air or N2O, associated with different fractions of inspired oxygen (FiO2). The group subject to 30% of compressed air (GA30) showed the closest proximity to the physiological range of partial pressure (PaO2) expected for the species. For oxygen saturation (SaO2), the values obtained were below the lower physiological limit in the group administered 30% N2O (GN30). Use of PEEP positively interfered in PaCO2 independent of FiO2, however, its effectiveness can be compromised when complemented by N2O-based anesthesia. For SaO2, only GN30 showed values lower than adequate for maintaining tissue oxygenation. The pH, base deficit and bicarbonate in arterial blood were influenced by FiO2 and N2O. In conclusion, the use of compressed air maintains blood gas parameters at their most stable, especially GA30 and PEEP, which seemed to positively influence the experimental groups, with some interference from FiO2 and N2O.(AU)

Compararam-se os efeitos de diferentes concentrações do óxido nitroso ou oxigênio sobre variáveis hemogasométricas, em suínos mantidos em ventilação espontânea ou controlada à pressão, associada ou não à pressão expiratória final positiva (PEEP). Foram utilizados 48 porcos, distribuídos em seis grupos. Administraram-se diferentes concentrações de ar comprimido ou N2O, associadas a diversas frações de oxigênio inspirado (FiO2). O grupo sujeito a 30% de ar comprimido (GA30) mostrou maior proximidade do intervalo fisiológico da pressão parcial de oxigênio (PaO2). Para a saturação de oxigênio (SaO2), observaram-se valores aquém do limite inferior fisiológico no grupo administrado com 30% de N2O (GN30). A utilização da PEEP é capaz de interferir positivamente na PaCO2, independentemente da FiO2, porém tem a efetividade comprometida quando há complemento da anestesia com o N2O. Para a SaO2, apenas o GN30 esboçou valores inferiores aos adequados para manutenção da oxigenação tecidual. O pH, o déficit base e o bicarbonato no sangue arterial foram influenciados pela FiO2 e pelo N2O. Concluiu-se que o uso do ar comprimido mantém os parâmetros hemogasométricos mais estáveis, com destaque para o GA30 e a PEEP, o que parece influenciar positivamente os grupos experimentais, mas com interferência da FiO2 e do N2O.(AU)

Hazelnut and cocoa spread improves flow-mediated dilatation in smokers.

Hazelnut and cocoa spread is an Italian product containing cocoa and hazelnut. Several epidemiological studies suggest that cocoa and hazelnuts cocoa exert beneficial cardiovascular effects. To investigate whether in smokers, hazelnut and cocoa spread elicits artery dilatation via down-regulation of oxidative stress. Flow-mediated dilatation (FMD), oxidative stress (as assessed by serum isoprostanes excretion, Nox2 activation and NO bioavailability) and antioxidant status [as assessed by vitamin E levels, plasma total polyphenols and H2O2 breaking down activity (HBA)] were studied in 20 smokers in a crossover, single-blind study. Patients were randomly allocated to 60 g of Hazelnut and cocoa spread or 60 g of milk chocolate (≤ 35% cocoa). FMD, serum isoprostanes, Nox2 activation, NOx, vitamin E, HBA and total polyphenols were assessed at baseline and 2 h after chocolate ingestion. After Hazelnut and cocoa spread intake, FMD and NOx significantly increased (from 4.3 ± 2.8 to 8.0 ± 3.2%, p < 0.001 and from 23.1 ± 5.5 to 32.0 ± 12.6 µM, p = 0.016, respectively); conversely, serum isoprostanes and Nox2 activation significantly decreased (from 302.8 ± 59.8 to 240.7 ± 90.8 pmol/l, p = 0.03 and from 25 ± 4.4 to 22.6 ± 3.2, p = 0.03, respectively). After Hazelnut and cocoa spread intake, serum total polyphenols, vitamin E and HBA significantly increased (from 133.8 ± 49.7 to 202.5 ± 69.5 mg/l GAE, p = 0.001; from 3.56 ± 1.4 to 4.5 ± 1.0 µmol/mmol cholesterol, p = 0.002 and from 63.3 ± 13.2 to 74.2 ± 12.4%, p = 0.003, respectively). No changes in the above variables were observed after milk chocolate intake. A linear correlation analysis shows that Δ (expressed by difference of values between before and after chocolate intake) of FMD correlates with Δ of total polyphenols and Δ of vitamin E. This study shows that Hazelnut and cocoa spread improves FMD with a mechanism potentially involving downregulation of oxidative stress and eventually increased NO generation in smokers.

A pilot randomised controlled trial investigating a Mediterranean diet intervention in pregnant women for the primary prevention of allergic diseases in infants.

BACKGROUND: Observational studies suggest a potentially protective role of the Mediterranean diet (MD) in allergic diseases, including asthma. Large scale randomised controlled trials (RCTs) are needed to test the hypothesised allergy-prevention benefits of a MD during pregnancy. The present two-arm pilot RCT in pregnant women at high-risk of having a child who would develop allergic disease investigated maternal recruitment, retention and acceptability of an MD dietary intervention in the UK. The trial also assessed the effect of the intervention on MD adherence scores at 12 and at 24 weeks post-randomisation. METHODS: Thirty women were recruited at around 12 weeks of gestation. Retention was high (28 out of 30; 93%). The intervention was acceptable to participants. Mean (SD) adherence to the MD at baseline was 12.4 (2.9) in the intervention arm (n = 14) and 13.0 (1.9) in the control arm (n = 16), where 24 represents maximal adherence. There was a favourable short-term change in MD score: the adjusted mean difference (intervention - control) in the change in MD score from baseline to 12 weeks post-randomisation was 2.4 (95% confidence interval = 0.6-4.2, P = 0.012). CONCLUSIONS: The trial provides important insights into recruitment, retention and sustaining the dietary intervention, which will be used in the design of a large RCT.

Metabolic effects of sapropterin treatment in autism spectrum disorder: a preliminary study.

Sapropterin, a synthetic form of tetrahydrobiopterin (BH4), has been reported to improve symptoms in children with autism spectrum disorder (ASD). However, as BH4 is involved in multiple metabolic pathway that have been found to be dysregulated in ASD, including redox, pterin, monoamine neurotransmitter, nitric oxide (NO) and immune metabolism, the metabolic pathway by which sapropterin exerts its therapeutic effect in ASD effect remains unclear. This study investigated which metabolic pathways were associated with symptomatic improvement during sapropterin treatment. Ten participants (ages 2-6 years old) with current social and/or language delays, ASD and a central BH4 concentration 30 nM l(-1) were treated with a daily morning 20 mg kg(-1) dose of sapropterin for 16 weeks in an open-label fashion. At baseline, 8 weeks and 16 weeks after starting the treatment, measures of language, social function and behavior and biomarkers of redox, pterin, monoamine neurotransmitter, NO and immune metabolism were obtained. Two participants discontinued the study, one from mild adverse effects and another due to noncompliance. Overall, improvements in subscales of the Preschool Language Scale (PLS), Vineland Adaptive Behavior Scale (VABS), Aberrant Behavior Checklist (ABC) and autism symptoms questionnaire (ASQ) were seen. Significant changes in biomarkers of pterin, redox and NO were found. Improvement on several subscales of the PLS, VABS, ABC and ASQ were moderated by baseline and changes in biomarkers of NO and pterin metabolism, particularly baseline NO metabolism. These data suggest that behavioral improvement associated with daily 20 mg kg(-1) sapropterin treatment may involve NO metabolism, particularly the status of pretreatment NO metabolism.

Measurements of the persistent singlet state of N2O in blood and other solvents--potential as a magnetic tracer.

The development of hyperpolarized tracers has been limited by short nuclear polarization lifetimes. The dominant relaxation mechanism for many hyperpolarized agents in solution arises from intramolecular nuclear dipole-dipole coupling modulated by molecular motion. It has been previously demonstrated that nuclear spin relaxation due to this mechanism can be removed by storing the nuclear polarization in long-lived, singlet-like states. In the case of N(2)O, storing the polarization of the nitrogen nuclei has been shown to substantially increase the polarization lifetime. The feasibility of utilizing N(2)O as a tracer is investigated by measuring the singlet-state lifetime of the N(2)O when dissolved in a variety of solvents including whole blood. Comparison of the singlet lifetime to longitudinal relaxation and between protonated and deuterated solvents is consistent with the dominance of spin-rotation relaxation, except in the case of blood.

Nitrous oxide diffusion and the second gas effect on emergence from anesthesia.

BACKGROUND: Rapid elimination of nitrous oxide from the lungs at the end of inhalational anesthesia dilutes alveolar oxygen, producing "diffusion hypoxia." A similar dilutional effect on accompanying volatile anesthetic agent has not been evaluated and may impact the speed of emergence. METHODS: Twenty patients undergoing surgery were randomly assigned to receive an anesthetic maintenance gas mixture of sevoflurane adjusted to bispectral index, in air-oxygen (control group) versus a 2:1 mixture of nitrous oxide-oxygen (nitrous oxide group). After surgery, baseline arterial and tidal gas samples were taken. Patients were ventilated with oxygen, and arterial and tidal gas sampling was repeated at 2 and 5 min. Arterial sampling was repeated 30 min after surgery. Sevoflurane partial pressure was measured in blood by the double headspace equilibration technique and in tidal gas using a calibrated infrared gas analyzer. Time to eye opening and time extubation were recorded. The primary endpoint was the reduction in sevoflurane partial pressures in blood at 2 and 5 min. RESULTS: Relative to baseline, arterial sevoflurane partial pressure was 39% higher at 5 min in the control group (P < 0.04) versus the nitrous oxide group. At 30 min the difference was not statistically significant. Time to eye opening (8.7 vs. 10.1 min) and time to extubation (11.0 vs.13.2 min) were shorter in the nitrous oxide group versus the control group (P < 0.04). CONCLUSIONS: Elimination of nitrous oxide at the end of anesthesia produces a clinically significant acceleration in the reduction of concentrations of the accompanying volatile agents, contributing to the speed of emergence observed after inhalational nitrous oxide anesthetic.

[Level of nitrous oxide in peripheral blood serum in patients with various severity of arterial hypertension].

AIM: To elucidate the role of nitrous oxide (NO) in development of severe primary arterial hypertension (AH) including malignant hypertension and concomitant ischemic heart disease (IHD). MATERIAL AND METHOD: Patients with diagnosis of primary 1-3 degree AH (n=62, 21 men, 41 women aged 39-87 years, mean age 63.7+/-2.7 years) and 28 subjects with normal arterial pressure (AP) (n=28, 13 men, 15 women aged 30-85 years, mean age 57.5+/-7.8 years). Blood serum levels of NO stable metabolites (nitrates and nitrites) were measured by reaction of their reduction in the presence of vanadium chloride and by reaction of diazotization of sulfanilamide by generated nitrite (modification by R.M.Miranda et al., 2001). RESULTS: NO level (level of its stable metabolites) was substantially elevated in patients with various severity of AH compared with subjects with normal AP. Severe and malignant course of AH was not associated with substantial lowering of NO level in blood serum. Relation between NO level and age found in subjects with normal AP, was not observed in patients with labile and stable course of AH. In patients with AH, normal serum NO level and signs of chronic involvement of cardiovascular system the disease was several times more often associated with atrial fibrillation and class II-III angina than in patients with high NO levels. Patients with AH combined with IHD more often had signs of heart failure and history of myocardial infarction.

[Value of endothelial dysfunction in cardiovascular diseases and methods of its correction with drugs].

Vascular endothelium is not simply a barrier between blood and extra vascular bed but is a source of large number of mediators regulating various functions of the body among which nitrous oxide appears to be one of most important. Endothelial dysfunction (ED) develops in a number of processes: diabetes mellitus, smoking, arterial hypertension, hypercholesterolemia. ED promotes increase of rate development of cardiovascular diseases. One of most well known markers of ED is microalbuminuria (MAU). Drug and nondrug means are used for the treatment of ED. Calcium antagonists and angiotensin converting enzyme inhibitors both separately and as components of combination therapy are able to maximally diminish MAU.

[Effect of antihypertensive drugs on some humoral parameters of endothelial function].

We assessed effect of antihypertensive drugs from various classes on humoral parameters of endothelial function - levels of asymmetrical dimethyl-arginine (ADMA) and metabolites of nitrous oxide (MNO) - in 106 patients with I-II degree arterial hypertension before and after 2 weeks of treatment. Two weeks treatment with various antihypertensive drugs did not lead to significant changes of ADMA levels. However antihypertensive drugs from various classes produced different effects on levels of MNO. Combination antihypertensive preparation indapamide and perindopril caused significant elevation of MNO level in patients with I-II degree arterial hypertension what appears to be indirect reflection of augmentation of nitrous oxide formation and improvement of endothelial function.

The Severinghaus square root of time relationship for anesthetic uptake and its implications for the stability of compartmental pharmacokinetics.

For nitrous oxide, the first anesthetic for which uptake was measured in humans, Severinghaus noted empirically that a plot of the log of uptake against the log of elapsed time produced a straight line with slope -0.5, suggesting that uptake is proportional to the inverse square root of time. This result is something of a black box model, based on empirical curve fitting without regard to physiology. Some authors (e.g., Lowe) repeatedly returned to this inverse square root of time model as a benchmark while others (e.g., Hendrickx) questioned its validity and demanded the relationship be expressed with a physiologic model whose structure matches the known physiology being modeled. Nevertheless, the fact that authors have repeatedly come back to this inverse square root of time model as a benchmark suggests that it might have some underlying validity which has not previously been recognized. We re-explored this mathematically in an attempt to reveal hitherto undiscovered insights or limitations. In this study, we examined the square root of time model (viewed as a power function) and compared it with multi-compartment models. Further, we explored the stability of this relationship to systematic variation in the power value and also to the superimposition of noise-like perturbations, seeking conditions under which it might not work. Based upon this theoretical analysis, we also speculate on the existence of a physiological compartment with a time constant between that of the vessel-rich group (VRG) and muscle, and what the identity of such a compartment might be.

Magnitude of the second gas effect on arterial sevoflurane partial pressure.

BACKGROUND: A number of studies have demonstrated a faster rate of increase in end-expired partial pressure as a fraction of inspired (Pa/Pi) for volatile agents in the presence of high concentrations of nitrous oxide, consistent with the second gas effect. However, no study has demonstrated a similar effect on arterial blood concentrations. METHODS: The authors compared arterial and end-tidal partial pressures of sevoflurane (Pa/Pisevo and Pa/Pisevo) in 14 patients for 30 min after introduction of either 70% nitrous oxide or nitrous oxide-free gas mixtures to determine the magnitude of the second gas effect. Blood partial pressures were measured using a double headspace equilibration technique. RESULTS: Both Pa/Pisevo and Pa/Pisevo were significantly higher in the nitrous oxide group than in the control group (P < 0.001 on two-way analysis of variance). This difference was significantly greater (P < 0.05) for Pa/Pisevo (23.6% higher in the nitrous oxide group at 2 min, declining to 12.5% at 30 min) than for Pa/Pisevo (9.8% higher in the nitrous oxide group at 2 min) and was accompanied by a significantly lower Bispectral Index score at 5 min (40.7 vs. 25.4; P = 0.004). CONCLUSION: Nitrous oxide uptake exerts a significant second gas effect on arterial sevoflurane partial pressures. This effect is two to three times more powerful than the effect on end-expired partial pressures. The authors explain how this is due to the influence of ventilation-perfusion scatter on the distribution of blood flow and gas uptake in the lung.

Measurement of anesthetics in blood using a conventional infrared clinical gas analyzer.

BACKGROUND: Measurement of the partial pressure of volatile anesthetics in blood is usually done using a "headspace equilibration" method with gas chromatography. However, it is not often performed in clinical studies because of the technical, equipment, and logistic requirements. To improve the accessibility of this measurement, we tested the use of a common infrared clinical gas analyzer, the Datex-Ohmeda Capnomac, for this purpose. METHODS: After characterization of the linearity of the device in measuring the volatile anesthetic concentration in the presence of nitrous oxide, carbon dioxide, and water vapor, blood was tonometered with known concentrations of sevoflurane (actual value between 0.5% and 5.0%) in oxygen and oxygen/nitrous oxide mixtures, as well as mixtures of isoflurane and desflurane in oxygen. RESULTS: Mean bias (standard deviation) overall for sevoflurane in oxygen relative to the tonometered reference partial pressure was -4.5 (4.8%) of the actual concentration. This was not altered significantly by measurement in 40% oxygen/60% nitrous oxide. For isoflurane and desflurane it was -3.9 (3.3%) and -4.6 (3.8%), respectively, of the actual concentration. CONCLUSIONS: The accuracy and precision of measurement of volatile anesthetic gas partial pressures in blood by a double headspace equilibration technique, using a clinical infrared gas analyzer, were comparable to that achieved by previous studies using gas chromatography.

The role of antioxidant supplementation in occupational exposure to waste anaesthetic gases.

OBJECTIVES: Although the genotoxicity related to waste anaesthetic gases is controversial, a consistent number of observations have provided evidence for an increased level of DNA strand breaks. The goal of the research was to investigate this hypothesis and estimate the genoprotective role of antioxidant supplementation in technical anaesthesiology staff working in operating theatres. METHODS: Heparinized venous blood samples were collected from 17 exposed technical anaesthesiology staff (mean age 34.3 +/- 3.5 years) and non-exposed control group (mean age 32.2 +/- 3.4 years) and examined in the alkaline comet assay for DNA strand breakage. Vitamin E (300 mg/day) plus vitamin C (500 mg/day) were supplemented to the technical anaesthesiology staff for 12 weeks and blood samples were retaken and evaluated by comet assay. RESULTS: The DNA breakage observed in the lymphocytes of the technical anaesthesiology staff was 21.5 +/- 5.0, as calculated by total comet score (TCS). This score was significantly higher (P<0.001) than in the controls (8.6 +/- 4.7) before antioxidant treatment. Supplementation of vitamins E plus C significantly (P<0.01) reduced the mean TCS as 14.2 +/- 6.1. CONCLUSION: The results of our study indicate that occupational exposure to anaesthetic gases induces oxidative DNA damage. Supplementation of the diet for 12 weeks with vitamin C and vitamin E resulted in a significant decrease in the DNA damage.

Bispectral index and regional cerebral oxygen saturation during propofol/N2O anesthesia.

PURPOSE: A study was undertaken to compare the influence of midazolam, isoflurane, and aminophylline (which may antagonize anesthetic action) on bispectral index (BIS) and regional cerebral oxygen saturation (rSO(2)) during propofol/N(2)O anesthesia, and to test the hypothesis that the drug-induced changes in BIS values are accompanied by a change in rSO(2). METHODS: General anesthesia was administered to 36 patients with a continuous infusion of propofol to maintain a BIS value of 40 +/- 5. After baseline recordings, patients were randomly assigned to receive either midazolam, isoflurane, or aminophylline. Bispectral index values, rSO(2) using near-infrared spectroscopy, and hemodynamic parameters were recorded for 60 min. RESULTS: Midazolam (0.05 mg x kg(-1)) significantly decreased the BIS from 47.8 +/- 5.4 to 35.0 +/- 4.5 at five minutes after injection (P < 0.001 vs control) during propofol anesthesia, whereas the rSO(2) was unchanged. Similarly, isoflurane (1.1% end-tidal) decreased the BIS from 42.5 +/- 7.5 to 27.8 +/- 6.9 (P < 0.001) without affecting rSO(2). In contrast, aminophylline (3 mg.kg(-1)) was associated with an increase in BIS from 41.6 +/- 2.1 to 48.3 +/- 9.2 at five minutes after injection (P < 0.05) without affecting rSO(2). CONCLUSIONS: Midazolam or isoflurane-induced decreases in the BIS during propofol anesthesia were not accompanied by a decrease in rSO(2). Aminophylline significantly increased the BIS score during propofol anesthesia, suggesting that aminophylline can antagonize, at least in part, the sedative actions of propofol.

Application of Molecular Adsorbents Recirculating System to remove NO and cytokines in severe liver failure patients with multiple organ dysfunction syndrome.

BACKGROUND: Molecular Adsorbents Recirculating System (MARS) is a new promising artificial liver support therapy, the aim of this study was to assess the effectiveness of MARS to remove nitrous oxide (NO) and cytokines in severe liver failure patients with multiple organ dysfunction syndrome (MODS). METHODS: Sixty single MARS treatments were performed with length of 6-24 h on 24 severe liver failure patients (18 males/6 females) with MODS. RESULTS: The MARS therapy was associated with a significant removal of NO and certain cytokines such as TNF-alpha, IL-6, IL-8, and INF-gamma, together with marked reduction of other non-water-soluble albumin bound toxins and water-soluble toxins, these were associated with a improvement of the patients' clinical conditions including hepatic encephalopathy, deranged hemodynamic situation and as well as renal and respiratory function, thus resulted into marked decrease of Sequential Organ Failure Assessment (SOFA) score and improved outcome: nine patients were able to be discharged from the hospital or bridged to successful liver transplantation, the overall survival of 24 patients was 37.5%. CONCLUSION: We can confirm the positive therapeutic impact and safety to use MARS on liver failure patients with MODS associated with elevated levels of NO and cytokines.