The effect of lipoic acid and vitamin E therapies in individuals with the metabolic syndrome.

The metabolic syndrome is associated with abnormal glucose and lipid metabolism, insulin resistance, increased oxidative stress and pro-inflammatory activity that increase the risk of type 2 diabetes and cardiovascular disease. The aim of this study was to investigate the effect of treatment with the antioxidant α-lipoic acid (ALA) with or without vitamin E supplementation, on markers of insulin resistance and systemic inflammation and plasma nonesterified fatty acid (NEFA) concentrations in individuals with the metabolic syndrome. In a randomized, double-blind, placebo-controlled trial, subjects with the metabolic syndrome received ALA (600 mg/day, n = 34), vitamin E (100 IU/day, n = 36), both ALA and vitamin E (n = 41), or matching placebo (n = 40) for 1 year. Fasting circulating concentrations of glucose and insulin were measure every 3 months and NEFA, markers of inflammation, adiponectin and vitamin E were measured at 6 monthly intervals. Plasma NEFA concentrations decreased [-10 (-18, 0)%] at a marginal level of significance (p = 0.05) in those who received ALA alone compared with placebo and decreased [-8 (-14, -1)% (95% CI)] significantly (P = 0.02) in participants who were randomised to ALA with and without vitamin E compared with those who did not receive ALA. Fasting glucose, insulin, homeostatic model assessment of insulin resistance, adiponectin, and markers of inflammation did not change significantly during the study. These data suggest that prolonged treatment with ALA may modestly reduce plasma NEFA concentrations but does not alter insulin or glucose levels in individuals with the metabolic syndrome.

Comparison of a novel form of zinc with zinc oxide bolus licensed for prevention of facial eczema, and interaction with copper oxide in sheep.

To evaluate a novel elemental zinc bolus compared with a registered positive control zinc oxide bolus and assess serum zinc concentrations following concomitant treatment with a capsule containing copper oxide needles. Forty Romney-cross ewes were randomly allocated in a 2 × 2 factorial design study. On Day 0, 20 ewes received novel boluses containing elemental zinc (Investigational Veterinary Product, IVP) while 20 received a zinc oxide bolus (control; CP). Half the animals in each zinc treatment group (n = 10) were treated with a copper oxide needle capsule [Copasure® - Ewe]. Weekly, from Day -7 to 56, all ewes were assessed for signs of photosensitization, and for 10 ewes from each zinc treatment groups, samples were collected for analysis of serum GGT activity, serum zinc concentrations, faecal zinc concentrations and on Days -7 and 56, liver copper concentrations. Multivariable random-effects models assessed the effects of zinc treatment, copper treatment, treatment interactions and time on all analytes. Regression models examined associations between serum and faecal zinc concentrations and GGT activity. Low spore numbers indicated low Pithomyces chartarum challenge. Serum zinc levels were significantly higher in the IVP than in the CP group [p < 0.0001] and varied by time [p < 0.001] and positively associated with faecal zinc concentration [p < 0.001]. Copper treatment did not affect serum zinc [p = 0.82] or faecal zinc [p = 0.92] concentrations. Liver copper concentrations did not differ between zinc treatment groups on Day -7 [p = 0.6] or Day 56 [p = 0.95]. Only the CP/no copper group had no increase in liver copper concentrations.

Translation of the edited mRNA for cytochrome b in trypanosome mitochondria.

The type of RNA editing found in the kinetoplast-mitochondria of trypanosomes and related protozoa, involving uridylate insertions and deletions, creates translatable messenger RNAs (mRNAs) out of nonsense pre-edited RNAs by correcting encoded defects that vary from simple frameshifts to large "cryptic" regions. However, any evidence for translation of these mRNAs in the kinetoplast has been missing for decades. We identified a kinetoplast-encoded protein, apocytochrome b, whose mRNA is edited in the 5' region. The determined amino-terminal sequence of the protein coincides with the predicted sequence derived from the edited region, demonstrating that the cognate apocytochrome b mRNA is translated into a functional protein. This finding represents the first direct evidence for a functional translation system in the kinetoplasts.

Structure and function of the cytochrome bc1 complex of mitochondria and photosynthetic bacteria.

Progress has recently been made in the understanding of the function of the cytochrome bc1 complex and related proteins in the context of recent structural information. The structures support many features that were predicted from sequence analysis and biophysical studies, but contain some surprises. Most dramatically, it is apparent that the iron-sulfur protein can take up different positions in different crystals, suggesting a novel mechanism for electron transfer through domain movement. Evidence from studies of mutant strains, in which the function of the sites or the binding of inhibitors is perturbed, has provided clues about the mechanism.

Effect of an intramammary teat seal and dry cow antibiotic in relation to dry period length on postpartum mastitis.

Infusion of either a long-acting antibiotic preparation (cefalonium) or the same antibiotic preparation combined with an internal teat sealant (bismuth subnitrite) were compared for the effect on new intramammary infections at calving and clinical mastitis in the first 100 d of lactation, in relation to dry period length. For all cows, a significant reduction in the incidence of new infections in quarters at calving (3.7 vs. 7.3%) was found for the combination treatment group (150 cows) compared with the antibiotic-alone treatment (133 cows). With a dry period of 10 wk or longer, significantly fewer new quarter infections (3.8 vs. 11.4%) were found in those cows receiving the combination treatment compared with antibiotic treatment alone. When the dry period was less than 10 wk, the incidence of new infections in quarters treated with the combination treatment was lower than for the antibiotic treatment alone (3.7 vs. 6%) but this was not a statistically significant difference. Fewer infections caused by Streptococcus uberis and coagulase-negative staphylococci were found in cows receiving the combination treatment compared with the antibiotic treatment alone (not significant). Coliform isolates were less likely in cows receiving the combination treatment with the longer dry period but the numbers of new intramammary coliform infections were low for both dry period categories. Few infections were caused by coagulase-negative staphylococci. The incidence of clinical mastitis in the first 100 d of lactation in quarters infected at calving was significantly lower (4 vs. 15 cases) for the combination treatment than for the antibiotic treatment alone for both dry period lengths. The clinical incidence in quarters in which a pathogen was not detected in either of the samples taken after calving was comparable between groups. No significant difference was found in the total clinical incidence after calving for both groups irrespective of dry period length.

Purification and characterization of the proton translocating plasma membrane ATPase of red beet storage tissue.

Plasma membranes were prepared from red beet (Beta vulgaris L.) storage tissue by partition in an aqueous two-phase system. A highly active proton-translocating ATPase was purified from these membranes by lysophosphatidylcholine extraction and glycerol density gradient centrifugation. The ATPase activity was inhibited by vanadate or dicyclohexyl carbodiimide, but was insensitive to azide, nitrate and molybdate at concentrations which inhibit the F1ATPase, the tonoplast ATPase, and acid phosphatase. Inhibition by vanadate was consistent with a non-competitive mechanism, with Ki = 10 microM. The Km for Mg-ATP was about 1 mM, magnesium ions were required, and the activity was stimulated by KCl and by lysophosphatidylcholine. The optimal pH was 6.5. The molecular mass by gel filtration in the presence of 2 g/liter octyl glucoside was 600 kDa, while dodecyl sulfate gel electrophoresis gave a polypeptide molecular mass of 100 kDa. After blotting onto nitrocellulose, the purified enzyme did not bind concanavalin A, although a concanavalin A-binding peptide of the plasma membrane runs to nearly the same position on the gel and showed some tendency to co-purify with the ATPase. Phospholipid vesicles into which the purified ATPase had been incorporated by the freeze-thaw technique showed vanadate-sensitive, ATP-dependent proton uptake. When the ATPase was reconstituted into lipid membranes at high protein to lipid ratios and incubated with ATP, two-dimensionally crystalline arrays of protein molecules were formed.

Crystallographic location of two Zn(2+)-binding sites in the avian cytochrome bc(1) complex.

The chicken mitochondrial ubiquinol cytochrome c oxidoreductase (bc(1) complex) is inhibited by Zn(2+) ions, but with higher K(i) ( approximately 3 microM) than the corresponding bovine enzyme. When equilibrated with mother liquor containing 200 microM ZnCl(2) for 7 days, the crystalline chicken bc(1) complex specifically binds Zn(2+) at 4 sites representing two sites on each monomer in the dimer. These two sites are close to the stigmatellin-binding site, taken to be center Q(o) of the Q-cycle mechanism, and are candidates for the inhibitory site. One binding site is actually in the hydrophobic channel between the Q(o) site and the bulk lipid phase, and may interfere with quinone binding. The other is in a hydrophilic area between cytochromes b and c(1), and might interfere with the egress of protons from the Q(o) site to the intermembrane aqueous medium. No zinc was bound near the putative proteolytic active site of subunits 1 and 2 (homologous to mitochondrial processing peptidase) under these conditions.

X-ray diffraction by crystals of beef heart ubiquinol: cytochrome c oxidoreductase.

Beef heart mitochondrial ubiquinol:cytochrome c oxidoreductase has been crystallized in the shape of hexagonal bipyramids. At present the crystals diffract X-rays to 4.7 A. From preliminary analysis the diffraction pattern appears to be consistent with space group P6(1)22 or P6(5)22 and with unit cell parameters a = b = 212 A and c = 352 A.

Characterization of cytochrome b from Toxoplasma gondii and Q(o) domain mutations as a mechanism of atovaquone-resistance.

Atovaquone is active in vitro against the tachyzoites of Toxoplasma gondii at nanomolar concentrations and is used clinically to treat acute cases of human toxoplasmosis. In pursuit of the mechanism of action of atovaquone against T. gondii and to understand how resistance might arise, drug-resistant mutants were generated and examined. The previously uncloned cytochrome b gene of T. gondii was cloned and sequenced from wild type and resistant strains as this was a likely candidate for the target of the drug and thus a source of resistance. Mutations are present within the cytochrome b gene of atovaquone-resistant parasites (M129L and I254L) and represent alterations in two different regions of the ubiquinol-binding pocket (Q(o) domain) of cytochrome b, suggesting that atovaquone interferes with electron transport at the cytochrome bc(1) complex in T. gondii. A structural model for how this hydroxynaphthoquinone is binding within the Q(o) domain is presented. Further analysis of the cytochrome b gene suggested that the protein may differ from other homologues by terminating within the mitochondrial membrane. Cytochrome b becomes the first complete mitochondrial gene and cognate protein to be described for T. gondii.

Optimal etching time of glass ionomer cement for maximum bond of composite resin.

This study compares the bond strengths of a composite resin to a glass ionomer cement with two types of surfaces and four etching times and attempted to correlate the bond strengths with a scanning electron microscope (SEM). The bond strengths were significantly greater to the instrumented surface at all etching times and the composite resin would not bond to glass smooth, unetched glass ionomer.

Dentin surface treatments for the removal of the smear layer: an SEM study.

Previous studies have shown that the bond strength of glass ionomer to dentin can be increased by the removal of the smear layer. Seven materials readily available were evaluated for smear layer removal. Clinical conditions were simulated as closely as possible.

An evaluation of lenses designed to block light emitted by light-curing units.

A number of protective lenses are available to prevent ocular injury from wavelength spectrum generated by visible light. Four of the five lenses tested absorbed virtually all of the radiation transmitted in the 200 to 800 nm level. Protective eyewear should be used when blue and ultraviolet light-curing units are involved.

Bond strength of glass ionomers to coronal and radicular dentin.

A study was conducted to compare the shear bond strength of a glass-ionomer cement and glass-ionomer base to coronal and radicular dentin. Two different glass ionomers were bonded to paired coronal and radicular human dentin surfaces that had received no surface treatment or had been treated passively for 20 seconds with either 40% or 25% polyacrylic acid. When only the effect of the type of dentin surface was considered, glass-ionomer bonds were greater to radicular dentin than to coronal dentin. With one exception, bond strengths to both dentin surfaces were greater with the base ionomer (Ketac-Bond) than with the luting cement (Ketac-Cem). Bond strengths of both glass ionomers were greater after dentin surface treatment with either 25% or 40% polyacrylic acid than with no treatment.

Bond strength of composite to air-abraded enamel and dentin.

Human enamel and dentin were prepared with an air abrasion unit (KCP-2000), using two particle sizes (27 micrometers and 50 micrometers) of aluminum oxide. In vitro tensile bond strengths of a composite resin were determined after three enamel and three dentin surface treatments. Enamel treatments were: air abraded only, E-1; air abraded + adhesive, E-2; air abraded + acid etch + adhesive, E-3. Dentin surface treatments were air abraded only, D-1; air abraded + adhesive/no primer, D-2; air abraded + primer + adhesive, D-3. Etched enamel and dentin prepared with 600-grit SiC paper and adhesive served as controls. There were 10 replications for each condition. A dentin bonding system (Optibond) and a composite resin (Herculite XRV) were bonded to treated surfaces by light curing in an inverted, truncated cone die with a bond diameter of 3 mm. Samples were stored at 37 degrees C and 100% relative humidity for 24 hours and debonded in tension using a Universal Testing Machine at a 0.05 cm/min crosshead speed. Based on analysis of variance, there was no statistical difference between 27 micrometers and 50 micrometers aluminum oxide abrasive for both enamel and dentin. For enamel bond strengths, E-2 was significantly higher than E-1, and E-3 was significantly higher than E-1 and E-2. E-1 and E-2 were significantly lower than the control, while E-3 was not significantly different from the control (P < or = 0.05). For dentin bond strengths, D-2 was significantly higher than D-1, and D-3 was significantly higher than D-1 and D-2. All treatments except D-3 were significantly lower than the control (P < or = 0.05). Air-abrasion treatment of enamel and dentin alone resulted in reduced in vitro bond strengths as compared to etched enamel and dentin prepared with dentin adhesive and dentin primer.

Fluoride release from light-cured liners.

This study compared the relative amounts and patterns of fluoride release from six commercially available light-cured liners in artificial saliva over a 28-day period. Cavalite and two Zionomer products released relatively small amounts of fluoride. Timeline and XR Ionomer released the highest cumulative total of fluoride over time. During the last time interval (14-28 days), Timeline released the greatest amount of fluoride. Patterns of fluoride release for all materials were similar with the largest proportion of the total fluoride release being in the first 24-48 hours, followed by a dramatic reduction in release rate.

Errors associated with milk cell counting.

The accuracy of somatic cell counts in milk samples was investigated in four studies. First, the counts recorded by one milk buyer in one supply over six months ranged from 105,000 to 401,000 cells/ml with no apparent changes in the volume of milk consigned or the level of mastitis in the herd that would explain this wide range. Secondly, the counts in daily samples from one bulk milk supply for 28 days ranged from 84,000 to 282,000 cells/ml, again with no apparent changes in the performance of the herd to explain the wide range. Thirdly, the replicated counts recorded for one sample by three separate laboratories agreed closely; however, when a sample with a high cell count was interspersed then two of the three laboratories reported high cell counts suggestive of 'carry-over' in excess of the 2 per cent 'allowable' Finally, cell count data from three separate laboratories on samples from 21 cows for 33 days revealed problems with the misidentification of samples on the farm in 1 per cent of the samples, and misidentification and mishandling of 1 to 2.6 per cent of the samples in the laboratories. All three laboratories differentiated samples from cows with subclinical and clinical mastitis, but the mean cell count of the uninfected cows varied between the laboratories with one of them recording statistically significantly higher counts over the period.

Bond strength of resin composite to air-abraded enamel.

Tensile bond strengths of a resin composite-dentinal bonding system to air-abraded enamel were determined. Several cutting variables available on an air-abrasion cavity preparation system were investigated. Two tip diameters, two abrasive powder flow rates, and two air pressures were selected, producing cutting actions that ranged from the most to the least aggressive of the air abrasion system. After enamel surfaces were air abraded, they were etched for 30 seconds with 37% phosphoric acid or not etched. Tensile bond strengths of resin composite to air-abraded, acid etched enamel were significantly greater than were those to air-abraded, unetched enamel. There was no statistically significant difference between any combination of tip diameter, powder flow rate, or air pressure.

Air abrasion: an old technology reborn.

Recently, air abrasion has experienced a rebirth in restorative dentistry. Originally developed in the late 1940s, the principle of air abrasion is the imparting of kinetic energy to tiny aluminum oxide particles that are projected by a stream of compressed air or gas and expelled from a small nozzle. The force generated by the relatively hard particles striking a relatively hard surface is sufficient to cut into that surface. In the last decade, more than a dozen models of air abrasion units have been introduced into the marketplace and more are on the way. Manufacturers have developed air abrasion instruments that offer a broad range of features, from small table-top units to self-contained systems with compressors, vacuums, and curing lights. The costs range dramatically--from $1,000 to $20,000 or more--depending on the complexity of the features and attachments. Manufacturers make a variety of claims to support the value of this technology to the practicing dentist. A term often used to describe one of the benefits of air abrasion is microdentistry. The claim is that smaller, less invasive tooth preparations may be accomplished using air abrasion than with a traditional bur and air turbine. This may be true in some instances, but it would certainly depend on the operator's experience and ability to visually discern fine detail. Other claims about air abrasion are that it can be used to cut into tooth structure without local anesthesia and that it should be used on all stained grooves or fissures to determine if incipient carious lesions are present. Despite the limited number of clinical studies, the popularity of air abrasion continues to grow. To gain additional insight about these claims and to see what might be on the horizon for this technology, I spoke with three highly respected educators who are recognized for their expertise in air abrasion. What they said should give the reader a better understanding of how air abrasion might augment restorative dentistry procedures and techniques.

Glass ionomer restoratives.

This article gives an overview of the new hybrid (light-cured) glass ionomers, which are a combination of auto-cured glass ionomer and light-cured composite resin. The characteristics of these materials and the different brands available are discussed. A clinical technique for restoration of cervical lesions with these materials is presented.

A descriptive review of the peer and non-peer reviewed literature on the treatment and prevention of foot lameness in cattle published between 2000 and 2011.

The aim of this study was to collate and review the peer and non-peer reviewed English language literature on the treatment and prevention of foot lameness in cattle published since January 2000. The study aimed to identify deficits in knowledge and areas of disparity between what is recommended in the field by veterinarians, foot trimmers and advisors and what has been substantiated experimentally. Peer reviewed literature containing original work was gathered by searching three databases. Papers were categorised and reviewed if they contained material on treatment or prevention. Non-peer reviewed clinical materials were collated from a range of sources. The materials were reviewed and categorised based on whether they recommended a range of possible treatment and prevention strategies. The peer reviewed data base contained 591 papers, of which 286 contained information on treatment or prevention. The vast majority of papers (258) concerned prevention; only a small number covered treatment (31) and of these only three contained information on the treatment of sole ulcers or white line disease. The number of intervention studies and trials was low; most papers on prevention were observational. Generally, lesion specific outcomes were not described making the findings of these papers difficult to use clinically. The non-peer reviewed material contained 46 sources; they varied significantly in regard to the treatments they advocated with some texts directly contradicting each other. Some aspects of prevention recommended in these sources seemed poorly supported by findings from the research literature. Well designed intervention studies are required to address these deficits.