Basking is affected by season and influences oxygen consumption in desert-living striped mice

Small mammals that inhabit arid and temporally unproductive environments use several methods to conserve energy. Here, we investigate the energetic role of sun basking in striped mice Rhabdomys pumilio from the Succulent Karoo desert in South Africa. We observed mice in front of their nests for 140 h and recorded the time they spent basking during the non-breeding (dry) and the breeding (wet) seasons. We measured temperature changes in model mice to provide an indication of the heat that can be absorbed from the sun. Finally, we measured the oxygen consumption (circle dot O-2) of mice at their basking sites in the field both in the sun and in the shade. This was accomplished using a portable respirometry system with a metabolism chamber, which could be placed in and out of the sun. Observations showed that mice basked more often during the non-breeding than during the breeding season. During the former season, mice spent an average of 11.9 +/- 1.1 min (se) in the morning and 5.5 +/- 0.5 min in the afternoon per day basking. Within the metabolism chamber, circle dot O-2 decreased when the animal was in the sunshine compared with the shade. This effect occurred independent of the ambient temperature (T-a), indicating that a significant amount of radiant energy was absorbed from the sun. Basking may be an alternative to other energy-acquisition behaviours, such as foraging, which might be particularly useful at times when food is scarce.

Radiative lifetimes of metastable states of negative ions

We present a technique for measuring the radiative lifetimes of metastable states of negative ions that involves the use of a heavy-ion storage ring. The method has been applied to investigate the radiative decay of the np3 2P1/2 levels of Te–(n=5) and Se–(n=4) and the 3p3 2D state of Si– for which the J=3/2 and 5/2 levels were unresolved. All of these states are metastable and decay primarily by emission of E2 and M1 radiation. Multi Configuration Dirac-Hartree-Fock calculations of rates for the transitions in Te– and Se– yielded lifetimes of 0.45 s and 4.7 s, respectively. The measured values agree well with these predicted values. In the case of the 2D state of Si–, however, our measurement was only able to set a lower limit on the lifetime. The upper limit of the lifetime that can be measured with our apparatus is set by how long the ions can be stored in the ring, a limit determined by the rate of collisional detachment. Our lower limit of 1 min for the lifetime of the 2D state is consistent with both the calculated lifetimes of 162 s for the 2D3/2 level and 27.3 h for the 2D5/2 level reported by O'Malley and Beck and 14.5 h and 12.5 h, respectively, from our Breit-Pauli calculations.

The inactivation of bovine cathepsin B by novel N-chloro-acetyl-dipeptides. Application of the Houghten 'tea bag' methodology to inhibitor synthesis

In this study, a series of N-chloro-acetylated dipeptides were synthesised by the application of Houghten's methodology of multiple analog peptide syntheses. The peptides, all of which contain a C-terminal free acid, were tested as inactivators of bovine cathepsin B, in an attempt at exploiting the known and, amongst the cysteine proteinases, unique carboxy dipeptidyl peptidase activity of the protease. We have succeeded in obtaining a number of effective inactivators, the most potent of which-chloroacetyl-Leu-Leu-OH, inactivates the enzyme with an apparent second-order rate constant of 3.8 x 10(4) M-1 min(-1). In contrast, the esterified analog, chloroacetyl-Leu-Leu-OMe, inactivates the enzyme some three orders of magnitude less efficiently, lending credence to our thesis that a free carboxylic acid moiety is an important determinant for inhibitor effectiveness. This preliminary study has highlighted a number of interesting features about the specificity requirements of the bovine proteinase and we believe that our approach has great potential for the rapid delineation of the subsite specificities of cathepsin B-like proteases from various species. (c) 2005 Elsevier Inc. All rights reserved.

Synthesis, Kinetic Evaluation and Utilization of a Biotinylated Dipeptide Proline Diphenyl Phosphonate for the Disclosure of Dipeptidyl Peptidase IV-like Serine Proteases

In this study, we report on the synthesis, kinetic characterisation, and application of a novel biotinylated and active site-directed inactivator of dipeptidyl peptidase IV (DPP-IV). Thus, the dipeptide-derived proline diphenyl phosphonate NH(2)-Glu(biotinyl-PEG)-Pro(P)(OPh)(2) has been prepared by a combination of classical solution- and solid-phase methodologies and has been shown to be an irreversible inhibitor of porcine DPP-IV, exhibiting an over all second-order rate constant (k(i)/K(i)) for inhibition of 1.57 x 10(3) M(-1) min(-1). This value compares favourably with previously reported rates of inactivation of DPP-IV by dipeptides containing a P(1) proline diphenyl phosphonate grouping [B. Boduszek, J. Oleksyszyn, C.M. Kam, J. Selzler, R.E. Smith, J.C. Powers, Dipeptide phophonates as inhibitors of dipeptidyl peptidase IV, J. Med. Chem. 37 (1994) 3969-3976; B.F. Gilmore, J.F. Lynas, C.J. Scott, C. McGoohan, L. Martin, B. Walker, Dipeptide proline diphenyl phosphonates are potent, irreversible inhibitors of seprase (FAPalpha), Biochem, Biophys. Res. Commun. 346 (2006) 436-446.], thus demonstrating that the incorporation of the side-chain modified (N-biotinyl-3-(2-(2-(3-aminopropyloxy)-ethoxy)-ethoxy)-propyl) glutamic acid residue at the P(2) position is compatible with inhibitor efficacy. The utilisation of this probe for the detection of both purified dipeptidyl peptidase IV and the disclosure of a dipeptidyl peptidase IV-like activity from a clinical isolate of Porphyromonas gingivalis, using established electrophoretic and Western blotting techniques previously developed by our group, is also demonstrated.

Demonstration of glycated insulin in human diabetic plasma and decreased biological activity assessed by euglycemic-hyperinsulinemic clamp technique in humans

The presence and biological significance of circulating glycated insulin has been evaluated by high-pressure liquid chromatography (HPLC), electrospray ionization mass spectrometry (ESI-MS), radioimmunoassay (RIA), receptor binding, and hyperinsulinemic-euglycemic clamp techniques. ESI-MS analysis of an HPLC-purified plasma pool from four male type 2 diabetic subjects (HbA(1e) 8.1 +/- 0.2%, plasma glucose 8.7 +/- 1.3 mmol/l [means +/- SE]) revealed two major insulin-like peaks with retention times of 14-16 min. After spectral averaging, the peak with retention time of 14.32 min exhibited a prominent triply charged (M+3H)(3+) species at 1,991.1 m/z, representing monoglycated insulin with an intact M-r of 5,970.3 Da. The second peak (retention time 15.70 min) corresponded to native insulin (M-r 5,807.6 Da), with the difference between the two peptides (162.7 Da) representing a single glucitol adduct (theoretical 164 Da). Measurement of glycated insulin in plasma of type 2 diabetic subjects by specific RIA gave circulating levels of 10.1 +/- 2.3 pmol/l, corresponding to -9% total insulin. Biological activity of pure synthetic monoglycated insulin (insulin B-chain Phe(1)-glucitol adduct) was evaluated in seven overnight-fasted healthy nonobese male volunteers using two-step euglycemic-hyperinsulinemic clamps (2 h at 16.6 mug (.) kg(-1) (.) min(-1), followed by 2 h at 83.0 mug (.) kg(-1) (.) min(-1); corresponding to 0.4 and 2.0 mU (.) kg(-1) (.) min(-1)). At the lower dose, the exogenons glucose infusion rates required to maintain euglycemia during steady state were significantly lower with glycated insulin (P

Low-Energy Electron Attachment to the Dichlorodifluoromethane (CCl2F2) Molecule

Results from a joint experimental study of electron attachment to dichlorodifluoromethane (CCl2F2) molecules in the gas phase are reported. In a high resolution electron beam experiment involving two versions of the laser photoelectron attachment method, the relative cross section for formation of the dominant anion Cl- wits measured over the energy range 0.001-1.8 eV at the gas temperature T-G = 300 K. It exhibits cusp structure at thresholds for vibrational excitation of the v(3)(a(1)) mode due to interaction with the attachment channels. With reference to the thermal attachment rate coefficient k(T-e;T-G = 300 K) = 2.2(8) x 10(-9) cm(-3) s(-1) (fitted average from several data), a new highly resolved absolute attachment cross section for TG = 300 K was determined. Partial cross sections for formation of the anions Cl-, Cl-2(-), F-, ClF-, and CCl2F- were measured over the range 0-12 eV, using three different electron beam experiments of medium energy resolution. The dependence of the attachment rate coefficient k(T-e;T-G = 300 K) on electron temperature T-e wits calculated over the range 50-15 000 K, based on a newly constructed total cross section for anion formation at T-G = 300 K. R-matrix Calculations for Cl- production have been carried out for comparison with the experimental data. The R-matrix results are in line with the main experimental observations and predict the dependence of the DEA cross section on the initial vibrational level v(3) and on the vibrational temperature. Furthermore, the cross section for I Vibrational excitation of the v(3) mode hits been computed.

Adsorption and photocatalysed destruction of cationic and anionic dyes on mesoporous titania films: Reactions at the air-solid interface

Cationic dyes, such as methylene blue (MB), Thionine (TH) and Basic Fuschin (BF), but not anionic dyes, such as Acid Orange 7 (AO7), Acid Blue 9 (AB9) and Acid Fuschin (AF), are readily adsorbed onto mesoporous titania films at high pH (pH 11), i.e. well above the pzc of titania (pH 6.5), due to electrostatic forces of attraction and repulsion, respectively. The same anionic dyes, but not the cationic dyes, are readily adsorbed on the same titania films at low pH (pH 3), i.e. well below titania's pzc. MB appears to adsorb on mesoporous titania films at pH 11 as the trimer (lambda(max) = 570 nm) but, upon drying, although the trimer still dominates, there is an absorption peak at 665 nm, especially notable at low [MB], which may be due to the monomer, but more likely MB J-aggregates. In contrast, the absorption spectrum of AO7 adsorbed onto the mesoporous titania film at low pH is very similar to the dye monomer. For both MB and AO7 the kinetics of adsorption are first order and yield high rate constants (3.71 and 1.481 g(-1) min(-1)), indicative of a strong adsorption process. Indeed, both MB and AO7 stained films retained much of their colour when left overnight in dye-free pH 11 and 3 solutions, respectively, indicating the strong nature of the adsorption. The kinetics of the photocatalytic bleaching of the MB-titania films at high pH are complex and not well-described by the Julson-Ollis kinetic model [A.J. Julson, D.F. Ollis, Appl. Catal. B. 65 (2006) 315]. Instead, there appears to be an initial fast but not simple demethylation step, followed by a zero-order bleaching and further demethylation steps. In contrast, the kinetics of photocatalytic bleaching of the AO7-titania film give a good fit to the Julson-Ollis kinetic model, yielding values for the various fitting parameters not too dissimilar to those reported for AO7 adsorbed on P25 titania powder. (C) 2008 Elsevier B.V. All rights reserved.

Functional management of ankle sprains: what volume and intensity of walking is undertaken in the first week postinjury:what volume and intensity of walking is undertaken in the first week postinjury

BACKGROUND: Acute ankle sprains are usually managed functionally, with advice to undertake progressive weight-bearing and walking. Mechanical loading is an important modular of tissue repair; therefore, the clinical effectiveness of walking after ankle sprain may be dose dependent. The intensity, magnitude and duration of load associated with current functional treatments for ankle sprain are unclear.

AIM: To describe physical activity (PA) in the first week after ankle sprain and to compare results with a healthy control group.

METHODS: Participants (16-65 years) with an acute ankle sprain were randomised into two groups (standard or exercise). Both groups were advised to apply ice and compression, and walk within the limits of pain. The exercise group undertook additional therapeutic exercises. PA was measured using an activPAL accelerometer, worn for 7 days after injury. Comparisons were made with a non-injured control group.

RESULTS: The standard group were significantly less active (1.2 ± 0.4 h activity/day; 5621 ± 2294 steps/day) than the exercise (1.7 ± 0 .7 h/day, p=0.04; 7886 ± 3075 steps/day, p=0.03) and non-injured control groups (1.7 ± 0.4 h/day, p=0.02; 8844 ± 2185 steps/day, p=0.002). Also, compared with the non-injured control group, the standard and exercise groups spent less time in moderate (38.3 ± 12.7 min/day vs 14.5 ± 11.4 min/day, p=0.001 and 22.5 ± 15.9 min/day, p=0.003) and high-intensity activity (4.1 ± 6.9 min/day vs 0.1 ± 0.1 min/day, p=0.001 and 0.62 ± 1.0 min/day p=0.005).

CONCLUSION: PA patterns are reduced in the first week after ankle sprain, which is partly ameliorated with addition of therapeutic exercises. This study represents the first step towards developing evidence-based walking prescription after acute ankle sprain.

The development of a rapid immunobiosensor screening method for the detection of residues of sulphadiazine

A rapid imununoassay using an optical biosensor (BIAcore(TM)) for determining the presence of sulphadiazine (SDZ) residues in pig bile was developed. SDZ,cas immobilised onto the surface of a dextran-coated silicon chip and a solution containing SDZ antibody, sample and buffer was injected over the chip surface. The level of antibody binding to the chip was determined after 20 s and the surface of the chip was then regenerated over a 1-min period prior to another sample injection taking place. Standard curves were constructed to allow quantification of SDZ presence in sample. Concentrations ranging from 0 to 10.64 mu g ml(-1) SDZ were detected in bile samples taken from experimentally fed pigs and randomly selected pigs taken from a local slaughterhouse. These results were compared to the concentrations of SDZ detected by high-performance liquid chromatography: in associated tissues. When concentrations in bile exceeded 0.6 mu g ml(-1) SDZ, the corresponding edible tissue was above the maximum residue level (MRL), i.e. 0.1 mu g g(-1) in 13 out of 14 cases. Wizen the bile concentration was less than 0.6 mu ml(-1) the associated tissue concentrations never exceeded rite MRL. This experiment has indicated that biosensor analysis of bile is a highly effective method for detecting violative SDZ residues in meat.

PREDICTION OF NETILMICIN DISPOSITION IN NEONATES

Multiple regression analyses of data from 33 neonates who received netilmicin therapy showed that concurrent treatment with other drugs (Drg), creatinine clearance (CL(cr)), gestational age (GA), and an apgar score of less than 6 at 1 min (Agl') were significant determinants of netilmicin clearance. Apparent volume of distribution was significantly affected by postnatal age (PNA), gender, the presence of ascites and/or oedema (A/O), and whether or not the neonate was small for gestational age (SGA). The following formulae were obtained: CL (ml min-1 kg-1) = -0.108 - 0.210 (Drg) + 0.152(CL(cr)) + 0.019(GA) -0.128(Agl') (multiple R = 0.725, p

PHONOPHORESIS OF METHYL NICOTINATE - A PRELIMINARY-STUDY TO ELUCIDATE THE MECHANISM OF ACTION

The skin penetration enhancement effect of ultrasound (phonophoresis) on methyl nicotinate was investigated in 10 healthy volunteers in a double-blind, placebo-controlled, crossover clinical trial. Each treatment consisted of the application of ultrasound massage (3.0 MHz, 1.0 W/cm2 continuous output) or placebo massage (0 MHz) for 5 min to the forearms of the volunteers, followed by a standardized application of methyl nicotinate at intervals of 15 sec, 1 min, and 2 min postmassage. Percutaneous absorption of methyl nicotinate was monitored using laser Doppler velocimetry. Ultrasound treatment applied prior to methyl nicotinate led to enhanced percutaneous absorption of the drug, for example, ultrasound treatment data versus control data at 2 min showed significant increases (P

Role of charge in the radioprotection of E. coli by thiols.

The role of net charge (Z) of thiols in their ability to radioprotect cells has been investigated in a glutathione (GSH)-deficient strain of E. coli. This strain, 7, is deficient in the enzyme gamma-glutamylcysteine synthetase and allows the effects of added low molecular weight thiols to be studied. Using the gas explosion system it is possible to measure the chemical repair of the free-radical precursors of lethal lesions by thiols in intact cells. The first-order chemical repair rate in strain 7 is 280s(-1) in comparison with 1100s(-1) in the wild-type strain 1157. From the measured difference in the intracellular concentration of GSH between the wild-type and the mutant, this gives a second-order repair rate, k(r)'s of 1.23 +/- 0.3 X 10(5) dm(3)mol(-1)s(-1). Measurement of intracellular thiol levels after addition of various low molecular weight thiols showed that uptake was rapid, leading to stable thiol levels within 1 min. The ratios of the intracellular to extracellular concentrations (C-in/C-out) were 0.74 for 3-mercaptopropionic acid (Z=-1), 0.56 for 2-mercaptoethanol (Z=0), 1.47 for cysteamine (Z=+1) and 1.04 for WR1065 (Z=+2). The k(r)'s for these thiols were 1.3 +/- 0.5 X 10(5) dm(3)mol(-1)s(-1) for 30-mercaptopropionic acid, 3.3 +/- 1.6 x 10(5) dm(3)mol(-1)s(-1) for 2-mercaptoethanol, 3.9 +/- 1.1 X 10(5) dm(3)mol(-1)s(-1) for cysteamine and 2.7 +/- 1.1 X 10(6) dm(3)mol(-1)s(-1) for WR1065. These are lower and increase less with charge than previously published values for chemical repair in isolated pBR322 DNA, probably because of the association of nucleoproteins and polyamines with the cellular DNA of E. coli. However, the approximate three-fold increase in k(r) per unit increase in Z shows that the counter-ion condensation and co-ion depletion are important in determining the effectiveness of charged thiols in the radioprotection of E. coli.

Initial validation of the Behavioral Indicators of Infant Pain (BIIP)

Accurate pain assessment in preterm infants in the neonatal intensive care unit (NICU) is complex. Infants who are born at early gestational ages (GA), and who have had greater early pain exposure, have dampened facial responses which may lead to under-treatment. Since behavioral and physiological responses to pain in infants are often dissociated, using multidimensional scales which combine these indicators into a single score may limit our ability to determine the effects of interventions on each system. Our aim was to design a unidimensional scale which would combine the relatively most specific, individual, behavioral indicators for assessing acute pain in this population. The Behavioral Indicators of Infant Pain (BIIP) combines sleep/wake states, 5 facial actions and 2 hand actions. Ninety-two infants born between 23 and 32 weeks GA were assessed during 3, 1 min Phases of blood collection. Outcome measures included changes in BIIP and in Neonatal Infant Pain Scale (NIPS) scores coded in real time from continuous bedside video recordings; changes in heart rate (HR) were obtained using custom physiological processing software. Scores on the BIIP changed significantly across Phases of blood collection (p

Synergism between high-pressure processing and active packaging against Listeria monocytogenes in ready-to-eat chicken breast

The effects of high-pressure processing (HPP) in conjunction with an essential oil-based active packaging on the surface of ready-to-eat (RTE) chicken breast were investigated as post-processing listericidal treatment. Three different treatments were used, and all samples were vacuum packed: (i) HPP at 500. MPa for 1. min (control), (ii) active packaging based on coriander essential oil, and (iii) active packaging and HPP. When applied individually, active packaging and pressurisation delayed the growth of Listeria monocytogenes. The combination of HPP and active packaging resulted in a synergistic effect reducing the counts of the pathogen below the detection limit throughout 60. days storage at 4. °C. However, when these samples were stored at 8. °C, growth did occur, but again a delay in growth was observed. The effects on colour and lipid oxidation were also studied during storage and were not significantly affected by the treatments. Active packaging followed by in-package pressure treatment could be a useful approach to reduce the risk of L. monocytogenes in cooked chicken without impairing its quality. Industrial relevance: Ready-to-eat products are of great economic importance to the industry. However, they have been implicated in several outbreaks of listeriosis. Therefore, effective ways to reduce the risk from this pathogenic microorganism can be very attractive for manufacturers. This study showed that the use of active packaging followed by HPP can enhance the listericidal efficiency of the treatment while using lower pressure levels, and thus having limited effects on colour and lipid oxidation of RTE chicken breast.

Changes in quality and safety attributes throughout long term storage of tomato juice processed by high pressure.

Tomato is the second most widely grown vegetable crop across the globe and it is one of widely cultivated crops in Sri Lanka. However, tomato industry in Sri Lanka facing a problem of high postharvest loss (54%) during the glut coupled with heavy revenue loss to the country by importing processed products. The aim of this work is to develop shelf-stable tomato product with maximum quality characteristics using high pressure processing (HPP). Tomato juice with altered and unaltered pH was processed using HPP at 600 MPa for 1 min after blanching (90 oC/2 min). As a control tomato juice was subjected to thermal processing (TP) at 95 oC /20 min. Processed samples were stored under 20oC and 28oC for 9 month period and analysed for total viable count (TVC) and instrumental colour (L, a, b) value at 0,1,2 3, and 4 week and 2, 3, 6 and 9 months interval. The raw juice sample had initial 6.69 log10 CFU/ml and both TP and HPP caused a more than 4.69 log10 reduction in the TVC of juice and microbial numbers remained low throughout the storage period even at 3 months after storage irrespective of the storage temperature. Both TP and HPP treated samples had the redness ⤘a value’ of 14.44-17.15 just after processing and showed non-significant reduction with storage in all the treatments after 3 months. The storage study results and discussed in relation to the end goal and compared with the literature.