Wide Variation In Activity Research Articles

Assessing surgical research at the teaching hospital level.

To undertake a comprehensive needs assessment to determine the baseline of surgical research activity at a tertiary referral hospital in Sydney, Australia. The comprehensive needs assessment comprised three components: a retrospective audit of the hospital ethics committee records to identify surgical research activity; a survey of all 17 surgical departments about the availability of 10 potential research resources and a survey of surgical staff to ascertain perceptions of research culture at the organizational, team and individual levels. Of all research studies submitted to the hospital ethics committee in a 2-year period, only 9% were identified as surgical studies. Among the 17 surgical departments, there was wide variation in activity with only four defined as being 'research active'. On average, 52% of potential resources for surgical research were found to be in place within surgical departments. Only five departments were considered to be adequately research resourced (≥75% potential resources in place). Surgical research culture was rated 'moderate' at the organizational and team level, and 'low' at the individual level. Medical staff rated research capacity significantly higher at the team and individual levels compared to nursing staff. Collectively, the baseline results indicate there is considerable opportunity to enhance surgical research at the hospital level and to use this information to guide new and innovative approaches in the future.

Recovery of ambulation activity across the first six months post-stroke

Stroke survivors commonly adopt sedentary activity behaviours by the chronic phase of recovery. However, the change in activity behaviours from the subacute to chronic phase of stroke is variable. This study explored the recovery of ambulation activity (volume and bouts) at one, three and six months after hospital discharge post-stroke. A total of 42 stroke survivors were recruited at hospital discharge and followed up one, three and six months later. At follow-up, ambulation activity was measured over four days using the ActivPAL™ accelerometer. Measures included volume of activity and frequency and intensity of ambulation activity bouts per day. Linear mixed effects modelling was used to determine changes over time. There was wide variation in activity. Total step counts across all time points were below required levels for health benefits (mean 4592 SD 3411). Most activity was spread across short bouts. While most number of bouts was of low intensity, most time was spent in moderate intensity ambulation across all time points. Daily step count and time spent walking and sitting/lying increased from one month to three and six months. The number of and time spent in short and medium duration bouts increased from one to six months. Time in long duration bouts increased at three months only. Time spent in moderate intensity ambulation increased over time. No change was observed for any other measures. In future, it would be valuable to identify strategies to increase engagement in activity behaviours to improve health outcomes after stroke.

Exploring physical activity level in patients with thoracic cancer: implications for use as an outcome measure

Cachexia is common in patients with thoracic cancer impairing physical function and quality of life. New approaches which target muscle tissue are emerging and activity monitors could provide an objective assessment of their effect on physical function. We have collated data from three studies involving the use of one such monitor in order to benchmark aspects of physical activity for patients with thoracic cancer, explore how these relate to physician-rated performance status, and consider the implications for future studies. Patients with thoracic cancer and an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0-2 wore an ActivPAL™ monitor for 1 week. The mean time spent each day in a range of activities, e.g. standing or stepping, or their frequency, e.g. number of sit-to-stand transitions, steps taken, were calculated and compared according to ECOG PS. Data from 84 patients (54 male; mean (SD) age, 66 (9) years) were collated. Each day, patients spent a mean (SD) of 4.3 (2.0) h upright, completed 45 (17) sit-to-stand transitions and took 4,246 (2,983) steps. There was wide variation in each activity examined. All but the number of sit-to-stand transitions differed significantly between ECOG PS categories. These data provide a detailed insight into how physical activity levels decline across the range of ECOG PS categories studied. The wide variation in physical activity within each ECOG PS category suggests that this scale may lack sufficient sensitivity to evaluate new cachexia treatments. Our data help to inform future work in this area.

Contributions to the Natural History of Seven Species of Bornean Frogs

Abstract The anuran fauna of Borneo consists of 156 known species distributed in almost every potential microhabitat in the forested environments that formerly covered the island. Seven of these species are commonly encountered along almost every stream in forests below 750 m above sea level. Aspects of the natural history of these seven—Bufo asper, Limnonectes ibanorum, L. ingeri, L. kuhlii, L. leporinus, Rana megalonesa, and R. signata—are presented based on observations made at 25 localities scattered through Brunei and the Malaysian states of Sabah and Sarawak. Each species shows wide variation in activity (as measured by numbers seen) within and between streams within localities. Recapture of marked individuals of B. asper, L. ibanorum, L. ingeri, and L. leporinus permits estimation of growth rates and time to sexual maturity and, less certainly, to a coarse estimate of the length of reproductive life. Each of these four species showed extremely wide variation among individuals in terms of movements ...

Application of dextranases in sugarcane factory: Overcoming practical problems

Dextranases only have a small market and low volume sales compared to many other industrial enzymes. Consequently, research and development efforts to engineer properties of dextranases to specific conditions of industrial processes have not occurred and are not expected soon. This book chapter highlights the difficulties associated with the practical application of dextranases, that are sometimes applied to hydrolyze dextran in sugar manufacture when bacterial deterioration of sugarcane or sugarbeet has occurred. Less than optimum application existed because of confusion about where to add the dextranase in the factory/refinery and which commercial dextranase to use. The wide variation in activity of commercially available dextranases in the U.S., and a standardized titration method to measure activities at the factory are discussed. Optimization by applying “concentrated” dextranase as a working solution to heated juice is described. Promising short-term technologies to further improve industrial dextranase applications are discussed, as well as the long-term outlook.

Diazinon, chlorpyrifos and parathion are metabolised by multiple cytochromes P450 in human liver

This research describes both the activation and detoxification of diazinon, chlorpyrifos and parathion by recombinant P450 isozymes and by human liver microsomes that had been characterised for P450 marker activities. Wide variations in activity were found for diazinon (50 μM; 500 μM) activation to diazoxon, chlorpyrifos (100 μM) to chlorpyrifos oxon and parathion (5 μM, 20 μM and 200 μM) to paraoxon in NADPH-dependent reactions. In parallel, the dearylated metabolites pyrimidinol (IHMP), trichloro-2-pyridinol (TCP) and p-nitrophenol (PNP) were produced from diazinon, chlorpyrifos and parathion, respectively, with similarly wide variations in activity. There were significant correlations between diazoxon formation from diazinon (50 μM; 500 μM) with the three CYP3A4/5 marker reactions, while IHMP formation correlated significantly with the three CYP3A4/5 reactions, the CYP2C8 marker reaction ( p < 0.05) and the CYP2C19 marker ( p < 0.01). Chlorpyrifos oxon formation from chlorpyrifos did not correlate with any of the P450 markers but TCP formation correlated with one of the CYP3A4/5 reactions ( p < 0.01) and CYP2C8 ( p < 0.01), CYP2C19 ( p < 0.01) and CYP1A2 ( p < 0.01) mediated reactions. There were significant relationships between paraoxon formation from parathion (5 μM, 20 μM and 200 μM) and the CYP3A4/5, CYP2C8 and CYP1A2 mediated reactions, although only the latter two isoforms correlated significantly with the lowest parathion concentration. Recombinant CYPs 2D6, 2C19, 3A5, 3A4 were most efficient in producing diazoxon and IHMP from diazinon; CYPs 2D6, 3A5, 2B6 and 3A4 were best at producing chlorpyrifos-oxon and CYPs 2C19, 2D6, 3A5 and 3A4 at producing TCP from chlorpyrifos (100 μM). These data strongly suggest that CYPs 3A4/5, 2C8, 1A2, 2C19 and 2D6 are primarily involved in the metabolism of all three OPs, although the profile of participating isoforms was different for each of the pesticides suggesting that chemical structure influences which P450s mediate the reaction. The marked inter-individual variation in expression of the various P450 isozymes may result in sub-populations of individuals that produce higher systemic oxon levels with increased susceptibility to OP toxicity.

Genetic and other sources of variation in the activity of serum paraoxonase/diazoxonase in humans: consequences for risk from exposure to diazinon

Diazinon is the only organophosphorus insecticide that is currently approved for use in sheep dip in the UK. Reports that some individuals may be genetically more susceptible to possible chronic adverse health effects, due to variations in PON1 activity, are complicated by the reliability of activity measurements. In the present study, the influence of three polymorphisms of PON1 on serum diazoxonase activity was investigated in 85 healthy volunteers. Serum activity was assessed in as close to physiological conditions as possible (at pH 7.4, 150 mM NaCl and 37 degrees C with 50 microM diazoxon as substrate) and by quantifying pyrimidinol formation using high-performance liquid chromatography. PON1 genotypes were determined by the polymerase chain reaction and restriction enzyme digestion. For PON1 Q192R, individuals with the RR genotype had the highest serum diazoxonase activity, in contrast to some previous reports where activity was determined under less physiological conditions. Activity was slightly reduced in individuals with the QR genotype and activity was reduced even further in those with the QQ genotype. For PON1 L55 M, there was a significant decrease in mean enzyme activity from LL>LM>MM genotypes. The promoter polymorphism PON1 -108 C/T had only a slight effect on activity. Overall, intragenotype variation in PON1 activity was appreciably greater than the mean intergenotype differences. In conclusion, although there is a wide variation in activity in individuals both within and between genotypes, those individuals with a combination of Q and M alleles generally have a lower ability to detoxify diazoxon, which implies a potentially greater susceptibility to toxicity from diazinon.

Esterolytic and Lipolytic Activities of Lactic Acid Bacteria Isolated from Ewe's Milk and Cheese

In the present work, we report on the esterase and lipase activities of lactic acid bacteria representing the genera Lactococcus, Leuconostoc, Lactobacillus, and Enterococcus isolated from ewe's milk and cheeses. Esterase activity was studied using α- and β-naphthyl derivatives of 2 to 12 carbon atoms and postelectrophoretic detection. The lactic acid bacteria evaluated had intracellular esterase activities, which preferentially degraded the α- and β-naphthyl derivatives of 2 to 6 carbon atoms. By studying postelectrophoretic patterns, it was found that some strains presented more than one esterase. Lactobacillus plantarum O236 showed four enzymes that hydrolyze carboxyl ester linkages with different specificity. Lipase activity was studied in intracellular and extracellular fractions using tributyrin, tricaprylin, triolein, and milk fat as substrates. The intracellular and extracellular fractions of Leuconostoc mesenteroides O257, Lactobacillus plantarum O236, and Lactobacillus acidophilus O177 were able to hydrolyze tributyrin. L. plantarum O186, L. acidophilus O252, Enterococcus faecium O174 and O426, and Enterococcus faecalis Ov409 showed lipase activity associated with the intracellular fraction on tributyrin. Lactococcus lactis O233, L. plantarum O155, and Lactobacillus casei O190 did not hydrolyze triglycerides. Not all strains that showed esterase activity exhibited high activity on triglycerides. Esterase and lipase activities were species- and strain-specific. Wide variations in activity between strains highlight the need for selecting appropriate starters to produce enzyme-modified cheese as well as accelerated ripened cheese.

Diazinon Is Activated by CYP2C19 in Human Liver

Phosphorothioate compounds are used throughout the world as agricultural and domestic pesticides. Here, the activation of the phosphorothioate diazinon to diazoxon in human liver is described. In an initial study using three human liver microsomal samples, Km for diazoxon formation varied markedly (31, 208, and 660 μM; Vmax 1125, 685, and 1028 pmol/min/mg protein, respectively), suggesting the involvement of more than one P450 enzyme. A wide variation in activity was found using 50 μM diazinon as substrate, (11–648 pmol/min/mg protein, n = 15), whereas, with 500 μM, variation was less (164–978 pmol/min/mg protein). Among eight P450-catalyzed reactions, the putative high-affinity component (50 μM diazinon) correlated with S-mephenytoin 4′-hydroxylase activity (r = 0.686, p < 0.01), suggesting the involvement of CYP2C19. The putative low-affinity component (500 μM diazinon) correlated with both S-mephenytoin 4′-hydroxylase (r = 0.714; p < 0.005) and high-affinity phenacetin O-deethylase activity (r = 0.625; p < 0.05). This activity was partially inhibited by furafylline, troleandomycin, and ketoconazole. These data suggest contributions from CYP2C19, CYP1A2, and CYP3A4. None of the inhibitors affected the high-affinity component. Of seven heterologously expressed human P450 enzymes, CYP2C19 activated diazinon (500 μM) at the fastest rate, followed by CYP3A4, CYP1A2, and CYP2C9. Both hepatic microsomal S-mephenytoin 4′-hydroxylase and high-affinity phenacetin O-deethylase activities were strongly inhibited by diazinon (IC50 < 2.5 μM), while no effect was seen on midazolam 1′-hydroxylase activity. These data indicate that CYP2C19 is the major enzyme involved in diazinon activation in human liver, while other enzymes including CYP1A2 may play a more minor role.

Mutational analysis of the human MAOA gene.

The monoamine oxidases (MAO-A and MAO-B) are the enzymes primarily responsible for the degradation of amine neurotransmitters, such as dopamine, norepinephrine, and serotonin. Wide variations in activity of these isozymes have been reported in control humans. The MAOA and MAOB genes are located next to each other in the p11.3-11.4 region of the human X chromosome. Our recent documentation of an MAO-A-deficiency state, apparently associated with impulsive aggressive behavior in males, has focused attention of genetic variations in the MAOA gene. In the present study variations in the coding sequence of the MAOA gene were evaluated by RT-PCR, SSCP, and sequencing a mRNA or genomic DNA in 40 control males with > 100-fold variations of MAO-A activity, as measured in cultured skin fibroblasts. Remarkable conservation of the coding sequence was found with only 5 polymorphisms observed. All but one of these were in the third codon position and thus did not alter the deduced amino acid sequence. The one amino acid alteration observed, lys --> arg, was neutral and should not affect the structure of the protein. This study demonstrates high conservation of coding sequence in the human MAOA gene in control males, and provides primer sets which can be used to search genomic DNA for mutations in this gene in males with neuropsychiatric conditions.

DNA Strand Breakage, Thymine Glycol Production, and Hydroxyl Radical Generation Induced by Different Samples of Crystalline Silica in Vitro

Five preparations of α-quartz [Min-U-Sil 5 (MQZ), MQZ pretreated with hydrofluoric acid (HFMQZ), Chinese standard α-quartz (CSQZ), and two German samples, DQ-12 and F600] and two preparations of the crystalline silica polymorphs, cristobalite and tridymite, previously characterized for surface area and surface charge, were evaluated for their relative activities in the following assays: (i) in vitro assays of short duration (≤ 15 min) for oxygen consumption and for generation of hydroxyl radicals (measured by electron spin resonance spin trapping), and (ii) in vitro assays of longer duration for DNA strand breakage (measured using linear DNA as a detector molecule) and for production of the oxidized DNA base, thymine glycol (measured by gas chromatography-mass spectrometry). Marked differences among the samples were found for their levels of oxygen consumption and of hydroxyl radicals′ generation. All samples caused increased formation of thymine glycol, with wide variations in activity among samples. When normalized for equal surface area, the samples produced different levels of DNA strand breakage. Addition of hydrogen peroxide strongly accelerated DNA damage-more for cristobalite than for the α-quartz samples. DNA damage by quartz was enhanced by ferric chloride and inhibited by iron chelators. The order of relative activity of the samples varied with different types of in vitro assays and was not directly correlated to surface area. Electrophoretic mobility, as measured by zeta potential, was not significantly different among samples. The results suggest that the ability of different crystalline silica samples to generate a rapid burst of oxygen free radicals is distinct from their ability to induce DNA damage and DNA base oxidation over longer time periods. The relative activities of the samples in cellular assays (hemolysis of human erythrocytes; cytotoxicity and neoplastic transformation of BALB/3T3/A31-1-1 cells) were in turn markedly different from those listed above, suggesting a more critical role for surface area. The mechanisms of carcinogenesis by crystalline silica need to be further investigated in relation 60 the underlying physicochemical characteristics.

Characterisation of the activities associated with fast reactor cladding hulls

Four batches of hulls from the reprocessing of fuel from the Prototype Fast Reactor at Dounreay have been examined visually and photographically. The appearance of the hulls (shiny or black) depended on the original location in the fuel pin. The total fissile activities measured corresponded to less than 0.1% of the original fuel. The α-emitter, fission product and activation product activities have been determined from dissolution studies. Profile diagrams have been constructed for the distribution of the principal activities along lengths of seventeen hulls. The evidence obtained suggested that much of the activity on the hulls arose through deposition from the dissolver liquors. The deposits included insoluble particulate material which was thought to be responsible for the wide variations in activity across short lengths of some of the hulls.

Characteristics of Thyroxine 5′-Deiodinase Activity in Human Liver

The conversion of thyroxine (T4) to triiodothyronine (T3) was studied in homogenates and subcellular fractions of 10 human liver specimens obtained postmortem. Preliminary studies indicated that T4 5'-deiodinase activity did not decline in rat liver kept at 5 degrees C for 6 and 24 hr after death. All human liver homogenates but one catalyzed T3 production, although the quantity of T3 produced varied greatly, from 8-fold in the absence of dithiothreitol (DTT) to 100-fold in its presence. The wide variation in activity found may reflect either postmortem loss or premortem decline in enzyme activity due to unrecognized nonthyroidal illness. The amount of T3 produced was dependent on substrate availability, protein concentration, time, pH and temperature, and enzyme activity was greatest in the microsomal fraction. T3 production was stimulated by DTT and inhibited by propylthiouracil (PTU). Thus, human liver T4 5'-deiodinase has properties very similar to the same enzyme in rat liver. These data suggest that results of studies of the effects of nonthyroidal illnesses and drugs on T4 5'-deiodinase activity in rat liver may be extrapolated to humans.

Studies on the glutathione S-transferase of human platelets

The glutathione S-transferases of human platelets have been compared with those of erythrocytes. Although wide variations in activity were found, in individual subjects, the activity in these cell types was significantly correlated. The enzymes demonstrated similar isoelectric points and electrophoretic mobilities and it appears that the platelet enzyme is also a product of the GST3 locus. There was no correlation between platelet enzyme activity and plasma concentrations of retinol and cholesterol, but in men, the relationship between activity and carotene was significant. It is suggested that GST3 isoenzyme activity depends on vitamin A.

Isoelectric-focusing of galactokinase in lens and other tissues

Thin-layer isoelectric focusing was used to investigate galactokinase in lenses from humans, cows, rats, rabbits and also in other tissues (red cells, liver, kidney, brain, placenta) from these species. In each case the enzyme activity was present as a single isozyme. The isoelectric point was the same in lens, red cell and other tissues of the same species, but differed from species to species. Post-translational modification due to deamidation was not detected in the lens or red cell from these species. Galactokinase activities in whole tissue extract were determined in different tissues of the various species. There were wide variations in activity. In the adult human lens, both normal and cataractous, it was low. The findings indicate that isoelectric focusing of RBC galactokinase combined with specific enzyme staining allows one to monitor lens galactokinase in patients with cataracts.

Studies on the quantitative variation of human red cell peptidase A activity.

SUMMARY1. A new method for the assay of peptidase A activity in human red cells and leucocytes is described.2. Wide variation in the level of red cell peptidase A activity between different individuals with the common electrophoretic phenotype Pep A1 has been demonstrated.3. Family studies show highly significant parent‐child and sib‐sib correlations, but no significant parent‐parent correlation. The findings indicate that the differences in level of activity between individuals are to a large extent genetically determined.4. Peptidase A activities in leucocytes show much less variation than in red cells. Only a small correlation, which was not statistically significant was found between red cell and leucocyte activity. In particular the levels of leucocyte peptidase A activity in individuals with very weak red cell activities were found to be very similar to those seen in individuals with strong red cell activity.5. Weak peptidase A activity in red cells was not found to be associated with weak activity of other red cell peptidases.6. No evidence for the differential occurrence of inhibitors or activators of peptidase A in red cells of individuals with different levels of activity was obtained in various experiments designed to test this possibility.7. The electrophoretic patterns seen in individuals heterozygous for certain rare alleles (Pep A5 and Pep A6) which determine electrophoretic variants of peptidase A suggest that two different alleles (provisionally called Pep A1S and Pep A1W) determining different forms of the enzyme with the usual electrophoretic mobility (Pep Al), but with different activities in red cells occur. Individuals presumed to be heterozygous for Pep A5 (or Pep A6) and for Pep A1S show a symmetrical triple‐banded electrophoretic pattern, which suggests that the activity attributable to Pep A5 or Pep A6 is about the same as that attributable to Pep A.1S. Individuals presumed to be heterozygous for the rare allele Pep A5 or Pep A6 and for Pep A1W show in red cells an asymmetrical electrophoretic pattern with a marked deficiency of activity attributable to Pep A1W. In leucocytes, however, they show a symmetrical electrophoretic pattern indistinguishable from the patterns observed in individuals with the same rare allele in heterozygous combination with the common allele Pep AS.8. It is suggested that the wide variation in activity seen in red cells of individuals with the common electrophoretic phenotype Pep A1, is at least in part attributable to alleles (Pep A1S and Pep A1W) occurring at the same locus as the alleles which determine previously described electrophoretic variants. However, it remains possible that allelic differences at other gene loci and producing their effects in different ways may also contribute to the genetically determined variation in activity.

Palladium-on-Charcoal Catalysts

The performance of charcoal-based catalysts cannot be described simply in terms of their mesh size and noble metal content, as many factors can cause wide variations in activity, selectivity and resistance to poisoning. It is possible, however, by close collaboration between catalyst manufacturer and user, and by suitable choice of base and production technique, to provide a range of such catalysts tailored to meet the needs of a particular industrial reaction.