Low Alcohol Concentrations Research Articles

Investigation of the permeation of model formulations and a commercial ibuprofen formulation in Carbosil ® and human skin using ATR-FTIR and multivariate spectral analysis

The purpose of the present study was to use attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and target factor analysis (TFA) to investigate the permeation of model drugs and formulation components through Carbosil ® membrane and human skin. Diffusion studies of saturated solutions in 50:50 water/ethanol of methyl paraben (MP), ibuprofen (IBU) and caffeine (CF) were performed on Carbosil ® membrane. The spectroscopic data were analysed by target factor analysis, and evolution profiles of the signal for each component (i.e. the drug, water, ethanol and membrane) over time were obtained. Results showed that the data were successfully deconvoluted as correlations between factors from the data and reference spectra of the components, were above 0.8 in all cases. Good reproducibility over three runs for the evolution profiles was obtained. From the evolution profiles it was observed that water diffused better through the Carbosil ® membrane than ethanol, confirming the hydrophilic properties of the Carbosil ® membrane used. IBU diffused slower compared with MP and CF. The evolution profile of CF was very similar to that of water, probably because of the high solubility of CF in water, indicating that both compounds are diffusing concurrently. The second part of the work involved a study of the evolution profiles of the components of a commercial topical gel containing 5% (w/w) of ibuprofen as it permeated through human skin. Although the system was much more complex, data were still successfully deconvoluted and the different components of the formulation identified except for benzyl alcohol which might be attributed to the low concentrations of benzyl alcohol used in topical formulations.

Molecular Simulation of Water/Alcohol Mixtures’ Adsorption and Diffusion in Zeolite 4A Membranes

The COMPASS (condensed-phase optimized molecular potentials for atomistic simulation studies) force field with two sets of partial atomic charges of water was used to simulate adsorption and diffusion behavior of water/methanol and water/ethanol mixtures in zeolite 4A at 298 K. The adsorption of alcohol first increased and then decreased with increasing pressure, whereas the adsorption of water increased progressively until an adsorption equilibrium was reached. Both the adsorbed molecules and the zeolite framework were treated as a fully flexible model in MD simulations. The simulation results show that the effects of the size and steric hindrance of the diffusing molecules on diffusivity are significant. The diffusivity of water, methanol, and ethanol molecules decreases by 1 order of magnitude in the order of water > methanol > ethanol. The diffusivity of water molecules depends on the mass fraction and the partial charges of water in zeolite 4A. The ethanol and methanol molecules have restricted motion through the alpha-cages, whereas the water molecules can easily pass through the alpha-cages window at low feed alcohol concentrations. And the extent of hydrogen bonding increased with increasing water concentration.

Partial molar volume of methanol in water: Effect of polarizability

The available pairwise additive intermolecular interaction models used so far in simulations in combination with common combining rules do not seem to be able to reproduce the most distinct feature of aqueous solutions of alcohols, the minimum of the partial molar volume at low alcohol concentrations. Nonetheless, this fundamental failure seems to have been paid little attention to, partly because of very high requirements for accuracy and, hence, CPU time of simulations. As an attempt to go beyond empirical combining rules and account in a more physical and yet simple way for the cross interactions, a feasibility study has been undertaken using a polarizable model of water in molecular simulations of the water–methanol mixture at ambient conditions. It turns out that the inclusion of polarizability may qualitatively change the behavior of the mixture bringing the result in agreement with experiment.

Heterogeneidade de álcoois secundários em aguardentes brasileiras de diversas origens e processos de fabricação

Secondary alcohol concentrations in sugar cane spirits from different origins were determined by gas chromatography. A great variation in the concentration of the secondary alcohols was found in these spirits. Of the 33 brands analyzed, 8 of them were found to be out of conformity with the legislation. Sec butanol, for which the maximum allowed concentration level is 100 mg.L-1 in absolute ethanol, was found within a concentration range between 5 mg.L-1, the limit of quantitation (LQ) and 408 mg.L-1 in absolute ethanol. Sugar cane samples from Salinas, MG, were the only ones that exhibited self similarity because of the low concentrations of n-butanol and n-amylic alcohol (< limit of detection LD).

Molar heat capacities for (2-methyl-2-butanol + heptane) mixtures and cyclopentanol at temperatures from (284 to 353) K

Isobaric specific heat capacities were measured for (2-methyl-2-butanol + heptane) mixtures and cyclopentanol within the temperature range from (284 to 353) K, and for 2-methyl-2-butanol in the (284 to 368) K temperature interval by means of a differential scanning calorimeter. The excess molar heat capacities were calculated from the experimental results. For the temperature range from (284 to 287) K, the excess molar heat capacity is S-shaped with negative values in the 2-methyl-2-butanol rich region and with small negative values at low alcohol concentrations at temperatures from (295 to 353) K. The excess molar heat capacities are positive for all compositions under test at temperatures from (288 to 294) K. The results are explained in terms of the influence of the molecular size and configuration of the alkanols on their self-association capability and of the change in molecular structure of the (2-methyl-2-butanol + heptane) mixtures. The differences between the temperature dependences of the heat capacities of the mixtures studied are qualitatively consistent with results obtained by Rappon et al. [M. Rappon, J.M. Greer, J. Mol. Liq. 33 (1987) 227–244; M. Rappon, J.A. Kaukinen, J. Mol. Liq. 38 (1988) 107–133; M. Rappon, R.M. Johns, J. Mol. Liq. 40 (1989) 155–179; M. Rappon, R.T. Syvitski, K.M. Ghazalli, J. Mol. Liq. 62 (1994) 159–179; M. Rappon, R.M. Johns, J. Mol. Liq. 80 (1999) 65–76; M. Rappon, S. Gillson, J. Mol. Liq. 128 (2006) 108–114].

Effect of driver distraction and low alcohol concentrations on useful field of view and frequency‐doubling technology perimetry

To investigate the effects of a mental psychometric task that simulates the distraction effect of a hands-free mobile phone and of low alcohol concentrations (0.3-0.5 g/l) on two tests: the useful field of view (UFOV) and frequency-doubling technology (FDT) perimetry. Thirty-seven healthy young vehicle drivers aged 22 +/- 3 years were subjected to a computer version of the UFOV test and FDT perimetry, undertaken according to a counterbalanced within-subject design. The tests were performed in two sessions (an 'alcohol session' and a 'sober session'), while undertaking or not undertaking a psychometric test [the Paced Auditory Serial Addition Test (PASAT)] to simulate the effect of distraction. Each subject was instructed to concentrate on the PASAT while taking each test. UFOV scores were affected when the PASAT was performed simultaneously (P < 0.0001) in that longer times were required to identify a central target and the location of a peripheral target. FDT perimetry was affected by the addition of the PASAT, with a significant reduction in mean sensitivity and a localized sensitivity loss [pattern standard deviation (PSD) >6 dB]. Test times, false-positive and negative catch trial responses were all increased. However, the UFOV test and FDT perimetry results were not significantly affected by a low alcohol concentration. Distraction significantly affects performance in the UFOV test and frequency-doubling technology perimetry. Our findings suggest that using a hands-free mobile phone while driving may lead to a low-to-moderate crash risk in young adults with normal visual function.

This issue of Acta

The illustration on the cover shows bilateral upper lid masses that happen to be encapsulated contact lenses as reported by Perera et al. in this issue of Acta. Stefánsson et al. suggest that ethics rules in medical research have become too strict and should be relaxed in retrospective clinical studies. Professor Morten la Cour in Copenhagen was the 2007 Acta-EVER lecturer and contributes a review paper on the physiology of the retinal pigment epithelium and its role in health and disease. Tarkkanen et al. in Helsinki found no difference in the prevalence of hypertension or ischemic heart disease between patients with primary open angle glaucoma and those with exfoliative glaucoma. However diabetes mellitus was less frequent among the exfoliative glaucoma patients. The same authors also contribute a letter to the editor where they suggest that the prevalence of age-related macular degeneration is similar in patients with primary open angle and exfoliative glaucoma. Saarela and Airaksinen in Oulu suggest that the Heidelberg retina tomograph may be used to detect small changes in optic nerve head and progressive retinal nerve fiber layer defects. Sato et al. in Japan find a strong association between retinal nerve fiber layer thickness and retinal sensitivity, but only when the atrophy of nerve fibers is relatively severe. Gauti Jóhannesson et al. in Umeå find a reasonable correlation and concordance between IOP measurements with Pascal, ICare and Goldman applanation tonometry. The ICare showed significantly dependency on central corneal thickness whereas Goldman applanation tonometry and Pascal tonometry showed significant dependency on corneal curvature. Vuori and Mäntyjärvi in Turku found that an exact correction of myopia is important to prevent false visual field interpretation in patients with tilted disc syndrome. Nakazawa et al. in Japan looked at changes in optic disc deviation and peripapillary crescent in eyes with mild or moderate myopia. They found the optic disc to deviate mostly nasally with the progression of myopia. Yu-Wai-Man et al. in Newcastle found no evidence of auditory dysfunction in 10 patients with Leber’s hereditary optic neuropathy. Puell and Barrio in Madrid suggest that distraction, such as cell phones, may impair a drivers useful visual field, whereas low concentrations of alcohol do not. Weeber and van der Heijde in the Netherlands created a computer model of the deformation of the lens during accommodation. Falck et al. in Oulu found that only one out of 220 persons over 60 years old in Finland was in current need of cataract surgery. This suggests that the supply of cataract surgery is extremely good. Akhtar et al. in United Kingdom, Switcherland and Austria describe the ultrastructural details of collagen fibrils and proteoglycan development in the zebrafish cornea, and suggest that this may be useful in the understanding of human corneal physiology and genetics. Kashiwabuchi et al. in Brazil suggest that penetrating keratoplasty may be useful for difficult cases of acanthamoeba keratitis. Gíavina-Bianchi et al. in Brasil have developed a mouse model for allergic conjunctivitis. Banat et al. in Germany examined light evoked responses from photoreceptor cells and other retinal cells in mouse and bovine retina in vitro. Minnella et al. in Rome found intravitreal bevacizumab to be safe and effective in 15 eyes with proliferative diabetic retinopathy and vitreous haemorrhages. Islam et al. in London discuss saccadic Lateropulsion. Malandrini et al. in Italy used confocal microscopy in a patient with recurrent conjunctival neoplacia. I hope the readers enjoy this issue of Acta.

Zero blood alcohol concentration limits for drivers under 21: lessons from Canada

Graduated licensing programs (GLPs) that include zero or low blood alcohol concentration (BAC) restrictions have proven to be a popular and effective measure for improving traffic safety among young people....

In-vivo efficacy of hand sanitisers against feline calicivirus: a surrogate for norovirus

Hand disinfection is considered important in preventing the transmission of viruses, including norovirus. We investigated the virucidal efficacy of nine hand sanitisers (four alcohol-based sanitisers, three non-alcoholic sanitisers and two triclosan-containing antimicrobial liquid soaps) against feline calicivirus, a surrogate for norovirus, on artificially contaminated fingertips for 30 s and 2 min contact periods. Among alcohol-based sanitisers, a product containing 99.5% ethanol was more effective than those containing 62% ethanol, 70% isopropanol or 91% isopropanol. A log(10) virus reduction factor of 1.00-1.30 was achieved with 99.5% ethanol but those containing a lower alcohol concentration only achieved a log(10) reduction factor of <or=0.67. Antiseptics containing 10% povidone-iodine (equivalent to 1% available iodine) reduced virus titre by a log(10) reduction factor of 2.67 within 30s contact time. This viral reduction rate was higher than that achieved with any of the alcohol-based sanitisers, non-alcoholic sanitisers or antimicrobial soaps. The two antimicrobial soaps tested showed minimal virus reduction (a log(10) reduction factor of 0.17-0.50), which is similar to that obtained by washing hands without any soap (a log(10) reduction factor of 0.33-0.42). These results indicate that triclosan-containing antimicrobial soaps or alcohol-based hand rubs may be inadequate for preventing norovirus transmission. Further research on alternative hand sanitisers should continue for effective control of norovirus infections.

Effects Of Moderate Sleep Deprivation and Low-Dose Alcohol On Driving Simulator Performance and Perception In Young Men

To determine the combined effects of sleep restriction and low-dose alcohol on driving simulator performance, EEG, and subjective levels of sleepiness and performance in the mid-afternoon. Repeated measures with 4 experimental conditions. Normal sleep without alcohol, sleep restriction alone (4 hours) and sleep restriction in combination with 2 different low blood alcohol concentrations (0.025 g/dL and 0.035 g/dL). Sleep Laboratory, Adelaide Institute for Sleep Health. Twenty-one healthy young men, aged 18-30 years, mean (+/-SD) = 22.5(+/-3.7) years, BMI = 25(+/-6.7) kg/m2; all had normal sleep patterns and were free of sleep disorders. Participants completed a 70-minute simulated driving session, commencing at 14:00. Driving parameters included steering deviation, braking reaction time, and number of collisions. Alpha and theta EEG activity and subjective driving performance and sleepiness were also measured throughout the driving task. All measures were significantly affected by time. Steering deviation increased significantly when sleep restriction was combined with the higher dose alcohol. This combination also resulted in a significant increase in alpha/theta EEG activity throughout the drive, as well as greater subjective sleepiness and negative driving performance ratings compared to control or sleep restriction alone. These data indicate that combining low-dose alcohol with moderate sleep restriction results in significant decrements to subjective alertness and performance as well as to some driving performance and EEG parameters. This highlights the potential risks of driving after consumption of low and legal doses of alcohol when also sleep restricted.

Comparative toxicology of fatal heroin overdose cases and morphine positive homicide victims

To compare the blood toxicology of heroin overdose cases and morphine positive homicide victims. Analysis of coronial cases. Sydney, Australia. Cases A total of 705 cases of death due to opioid toxicity and 28 morphine positive homicide cases (1 January 1998-31 December 2002). There was no significant difference between the median morphine concentrations of the overdose and homicide groups (0.50 versus 0.45 mg/l). The overdose group was more likely to have blood alcohol (OR 3.21) present, but less likely to have methadone (OR 0.26) and cannabis (OR 0.04). There was a significant negative correlation between blood morphine and alcohol concentrations among the overdose group (rho = -0.32), but not among the homicide group (rho = -0.03). Independent predictors of a higher blood morphine concentration were a lower alcohol concentration and a higher methadone concentration. Morphine concentrations per se are not diagnostic of overdose. The study confirms the salience of concomitant alcohol consumption in such events.

Cognitive impairment and increased brain neurosteroids in adult rats perinatally exposed to low millimolar blood alcohol concentrations

Epidemiological evidence suggests that adolescents and adults perinatally exposed to alcohol, even at low doses, show high prevalence of cognitive impairment and social behavior deficits, which may be in part related to alcohol-induced changes of the gamma-aminobutyric acid (GABA)ergic neurotransmission. The endogenous neurosteroid 3alpha-hydroxy,5alpha-pregnan-20-one (3alpha,5alpha-tetrahydroprogesterone/3alpha,5alpha-THP), a potent positive allosteric modulator of GABA(A) receptor function, is implicated in the physiological tuning of GABA-mediated fast inhibition and in various alcohol's actions in the brain. This study was undertaken to determine whether perinatal exposure to low millimolar blood alcohol concentrations alters cognitive skills (social discrimination and inhibitory avoidance tests), emotional reactivity (elevated plus maze test), and neurosteroid content in brain cortex and hippocampus of adult male offspring. Dams had access to a 3% alcohol solution or to an equicaloric sucrose solution from gestational day 15 to postnatal day 9. Eighty-day old alcohol-exposed male offspring exhibited impaired social recognition memory, but unchanged inhibitory avoidance performance and normal behavior on the elevated-plus maze. The concentrations of 3alpha,5alpha-THP and its precursor progesterone were more than doubled in brain cortex and hippocampus of alcohol-exposed rats, whereas in plasma only progesterone was increased. Thus, exposure to low millimolar blood alcohol concentrations has a long-lasting impact on the developing brain as it causes an impairment of social recognition as well as an increase of brain neurosteroid content in mature animals. The latter may be consequent to altered expression/activity of brain steroidogenic enzymes, as reflected by the enduring increase of the GABA(A) receptor-active neurosteroid 3alpha,5alpha-THP in brain cortex and hippocampus, but not in plasma. It is speculated that, by inducing a greater amplification of GABA(A) receptor function, the elevation of 3alpha,5alpha-THP brain content contributes to the cognitive impairment exhibited by adult alcohol-exposed offspring.

Triangular network of crystalline submicron rutile TiO2 block assembly: An alcohol sensor

Abstract RF sputtering technique was used to obtain periodic submicron triangular TiO2 blocks on quartz substrates at 500 °C. Preferentially oriented XRD patterns exhibiting the strongest line at 2θ = 27.78° suggested a rutile TiO2 block assembly. X-ray photoelectron spectroscopy confirmed that the surface composition of the particles corresponded to TiO2 with the absence of Ti3+ species at 500 °C after sputtering. Analysis of AFM images indicated that the single crystals were triangular in shape, self-assembled across the quartz surface. The sides of the triangular crystal obtained at 500 °C were found in the submicron range of 100–225 nm, whereas those sputtered at 300 °C were in the range of 250–375 nm. The image Z-range, Rq, Ra of TiO2 single crystal deposits sputtered at 500 °C were found to be 19.6, 3.1 and 2.5 nm, respectively, evidencing a smooth surface and regularly assembled single crystals. The crystalline submicron TiO2 film exhibited a sensor signal in the range of 2.3–10.8 to a low concentration (10–50 ppm) of alcohol at 250–500 °C. The reversibility of the sensor was also assessed.

Effects of a Moderate Evening Alcohol Dose. II: Performance

This second of a pair of papers investigates the effects of a moderate dose of alcohol and staying up late on driving simulation performance and simple visual reaction time (RT) at a known circadian phase in well-rested young adults. Twenty-nine adults (9 males), ages 21 to 25 years, spent 1 week on an at-home stabilization schedule of 8.5 to 9 hours, followed by 3 nonconsecutive nights in-lab: adaptation, placebo, and alcohol. Performance task practice occurred on 3 occasions before the study. Alcohol (vodka; 0.54 g/kg men; 0.49 g/kg women mixed with tonic) was consumed over 30 minutes ending 1 hour before normal bedtime; the same quantity of beverage was given on placebo. Driving simulation (with drive-only and dual-task drive and subtract components) and psychomotor vigilance task (PVT) testing occurred before and after alcohol/placebo ingestion. Breath alcohol concentration (BrAC) readings were taken before all test sessions. Saliva samples were taken approximately every 30 minutes to determine circadian phase. Driving simulation and PVT variables significantly deteriorated with increasing time awake. Driving simulator lane variability was worse with alcohol compared with placebo at 15.5 hours awake. No PVT variable showed an effect of alcohol. Driving simulation performance deteriorated with extended waking and with alcohol; driving was most impaired at the peak alcohol level. The PVT, less complex than the driving simulation, did not show effects of alcohol, a finding consistent with previous literature that disruptive effects of low alcohol concentrations increase with task complexity. Overall, simulated driving performance is significantly impaired late at night when even a moderate dose of alcohol is consumed.

P287 Microbial acetaldehyde formation from low alcohol concentrations - possible carcinogenic factor behind the consumption of fermented foodstuffs

P287 Microbial acetaldehyde formation from low alcohol concentrations - possible carcinogenic factor behind the consumption of fermented foodstuffs

Dielectric relaxation studies of alkanols solubilized by cationic surfactants in aqueous solutions

The influence of micellar stability on technological process has been an active area of research. Alcohols and oils are the most commonly used additives in micellar solutions to form various solubilized systems or micro emulsions for a wide range of industrial and technological applications. We report here the frequency dependence of the permittivities and the relaxation time of the micellar solutions of Cetyl Trimethyl Ammonium Bromide (CTAB) and Dodecyl Pyridinium Chloride (DPC) in water in the presence and absence of hexan-1-ol, octan-1-ol, decan-1-ol and ethane1,2diol. Time domain dielectric spectra were obtained in the reflection mode in the frequency range of 10 MHz to 20 GHz at 303 K using HP54750A Sampling oscilloscope and HP54754A TDR plug-in-module. The relaxation time of bound water was calculated using Cole–Cole method. The addition of alcohols results in a linear increase in the relaxation time in all the systems. As the concentration of alcohols increases τ/ η r attains a near constant value for aqueous DPC micellar solutions showing that solubilization becomes more difficult at these concentrations. The molar activation energy for viscous flow Δ F η is nearly constant in all systems showing no noticeable change in the hydrodynamical shape of the micelles, on addition of low concentration of alcohols.

Liquid–liquid phase behaviour, liquid–liquid density, and interfacial tension of multicomponent systems at 298 K

Experimental liquid–liquid phase diagrams are presented for the multicomponent systems isooctane–benzene–(80 mass% methanol + 20 mass% water)–5 mass% isobutyl alcohol (2-methyl-1-propanol) and isooctane–benzene–(80 mass% methanol + 20 mass% water)–15 mass% isobutyl alcohol, at 298.15 K. The density and interfacial tension of conjugate phases of concentration located in the isothermal binodal have been determined at 298.15 K for the partially miscible systems: isooctane–benzene–methanol, isooctane–benzene–(80 mass% methanol + 20 mass% water), isooctane–benzene–(80 mass% methanol + 20 mass% water)–5 mass% isobutyl alcohol, and isooctane–benzene–(80 mass% methanol + 20 mass% water)–15 mass% isobutyl alcohol. The experimental tie-line data define the binodal or coexistence curve of the two studied multicomponent systems and depending on the initial isobutyl alcohol concentration the liquid–liquid phase diagram is either of type II, with low alcohol concentration, or type I, with high concentration of alcohol, which is a clear indication that the solubility of the partially miscible systems is greatly enhanced via the co-solvency phenomenon. It is observed that both the density of each conjugate phase and the interfacial tension of each tie-line are valuable indicators of the degree of solubility of the multicomponent systems. Furthermore the experimental tie-lines data were correlated with the NRTL and UNIQUAC solution models with satisfactory quantitative results.

Alternative Membrane Protein Conformations in Alcohols

Alcohols modulate the oligomerization of membrane proteins in lipid bilayers. This can occur indirectly by redistributing lateral membrane pressure in a manner which correlates with alcohol hydrophobicity. Here we investigate the direct impact of different alcohol-water mixtures on membrane protein stability and solubility, using the two detergent-solubilized alpha-helical membrane proteins DsbB and NhaA. Both proteins precipitate extensively at intermediate concentrations of alcohols, forming states with extensive (40-60%) beta-sheet structure and affinity for the fibril-specific dye thioflavin T, although atomic force microscopy images reveal layer-like and spherical deposits, possibly early stages in a fibrillation process trapped by strong hydrophobic contacts. At higher alcohol concentrations, both DsbB and NhaA are resolubilized and form non-native structures with increased (DsbB) or decreased (NhaA) helicity compared to the native state. The alternative conformational states cannot be returned to the functional native state upon dilution of alcohol. The efficiency of precipitation and the degree to which DsbB is destabilized at low alcohol concentrations show the same correlation with alcohol hydrophobicity. Thus, in addition to their effect on the membrane, alcohols perturb membrane proteins directly by solvating the hydrophobic regions of the protein. At intermediate concentrations, this perturbation exposes hydrophobic segments but does not provide sufficient solvation to avoid intermolecular association. Resolubilization requires a reduction in the relative dielectric constant below 65 in conjunction with specific properties of the individual alcohols. We conclude that alcohols provide access to a diversity of conformations for membrane proteins but are not a priori suitable for solution studies requiring reversible denaturation of monomeric proteins.

Chinese yellow wine inhibits production of homocysteine-induced extracellular matrix metalloproteinase-2 in cultured rat vascular smooth muscle cells

Regular consumption of moderate amounts of Chinese yellow wine is associated with a reduced risk of coronary disease. Matrix metalloproteinases (MMPs) that participate in extracellular matrix degradation have been involved in atherosclerotic plaque growth and instability. The present research aimed to study the effects of Chinese yellow wine on the production of homocysteine (Hcy)-induced extracellular MMP-2 in cultured rats vascular smooth muscle cells (VSMCs). We examined the effects of different Hcy levels (0-1000 micromol/l) on MMP-2 production, and the effects of Chinese yellow wine with low alcohol concentrations (12-19%) on Hcy-induced MMP-2 in cultured rat (VSMCs) using gelatin zymography and western blotting. We further compared the changes of MMP-2 under various treatments for 12, 24 and 48 h. Hcy (50-1000 micromol/l) increased the production of MMP-2 significantly in a dose-dependent manner. Increased production of MMP-2 induced by Hcy was reduced by extracellularly added Chinese yellow wine. Production of MMP-2 under various treatments for 48 h increased more than 12 and 24 h. Extracellularly added Chinese yellow wine decreased Hcy-induced MMP-2 secretion. The inhibitory effect of yellow wine on the activation of MMP-2 might contribute to their beneficial effects on the cardiovascular system.

Metabolism of Silage Alcohols in Lactating Dairy Cows

Dairy cows fed silage are subjected to various alcohols and low molecular weight esters. Four lactating Holstein cows fitted with ruminal cannulas and permanent indwelling catheters in the hepatic portal vein, hepatic vein, mesenteric vein, and mesenteric artery were used to study the absorption of alcohols into portal blood and the metabolism of feed alcohols in the rumen and splanchnic tissues. The cows were allocated to 4 experimental treatments in a Latin square design. All treatments were formulated as total mixed rations with the same overall nutrient composition, differing by the source of corn silage. Treatments were a control silage and 3 qualities of problematic corn silage (silage with Fusarium toxin, Penicillium-infected silage, and silage with a high propanol content). Feeding was followed by a decreasing ruminal pH, as well as decreasing molar proportions of ruminal acetate and isobutyrate. The ruminal concentrations of total VFA, ethanol, propanol, 2-butanol, ethyl acetate, propyl acetate, glucose, and l-lactate, and molar proportions of propionate, butyrate, isovalerate, valerate, and caproate increased after feeding. Treatments affected ruminal concentrations of propanol, propyl acetate, and butyrate and a strong correlation was observed between ruminal propyl acetate and the molar proportion of butyrate (r=−0.79). Arterial concentrations of ethanol, propanol, propanal, acetone (sum of acetone and acetoacetate), 3-hydroxybutyrate, l-lactate, glutamate, and glutamine increased, and the arterial concentration of glucose decreased after feeding, but no effects of treatment were observed for arterial variables. The postprandial increase in arterial ethanol was maintained for 5h. The net portal release of ethanol tended to decrease with the treatment with the lowest ethanol content, and the net splanchnic release of ethanol increased after feeding, but overall, the net splanchnic flux of ethanol was not different from zero, in agreement with the liver being the major organ for alcohol metabolism. The net portal flux and net hepatic flux of propanol were affected by treatment. All dietary ethanol and propanol were accounted for by absorption of the respective alcohol into the portal blood. The hepatic extraction ratios of ethanol and propanol were, on average, 63 to 66%, and no indications of saturation of hepatic alcohol metabolism were observed at any time. We concluded that typical amounts of alcohols in corn silage do not interfere with splanchnic metabolism of any of the measured variables and do not saturate hepatic pathways for alcohol metabolism. However, even low concentrations of alcohols in feed might affect ruminal metabolism and are followed by hours of elevated peripheral blood concentrations of alcohols.