Skeletal Muscle Enzyme Research Articles

Regulation of Fasting Fuel Metabolism by Toll-Like Receptor 4

OBJECTIVEToll-like receptor 4 (TLR4) has been reported to induce insulin resistance through inflammation in high-fat–fed mice. However, the physiological role of TLR4 in metabolism is unknown. Here, we investigated the involvement of TLR4 in fasting metabolism.RESEARCH DESIGN AND METHODSWild-type and TLR4 deficient (TLR4−/−) mice were either fed or fasted for 24 h. Glucose and lipid levels in circulation and tissues were measured. Glucose and lipid metabolism in tissues, as well as the expression of related enzymes, was examined.RESULTSMice lacking TLR4 displayed aggravated fasting hypoglycemia, along with normal hepatic gluconeogenesis, but reversed activity of pyruvate dehydrogenase complex (PDC) in skeletal muscle, which might account for the fasting hypoglycemia. TLR4−/− mice also exhibited higher lipid levels in circulation and skeletal muscle after fasting and reversed expression of lipogenic enzymes in skeletal muscle but not liver and adipose tissue. Adipose tissue lipolysis is normal and muscle fatty acid oxidation is increased in TLR4−/− mice after fasting. Inhibition of fatty acid synthesis in TLR4−/− mice abolished hyperlipidemia, hypoglycemia, and PDC activity increase, suggesting that TLR4-dependent inhibition of muscle lipogenesis may contribute to glucose and lipid homeostasis during fasting. Further studies showed that TLR4 deficiency had no effect on insulin signaling and muscle proinflammatory cytokine production in response to fasting.CONCLUSIONSThese data suggest that TLR4 plays a critical role in glucose and lipid metabolism independent of insulin during fasting and identify a novel physiological role for TLR4 in fuel homeostasis.

A11 Alterations in the PGC-1 α dependent oxidative stress response in the R6/2 mouse model of HD

BackgroundIn Huntington's disease (HD), alterations in energy metabolism and mitochondrial function may result in oxidative stress. Increased levels of oxidative damage products have been reported in HD. The transcriptional co-activator...

Women Have Higher Protein Content of β-Oxidation Enzymes in Skeletal Muscle than Men

It is well recognized that compared with men, women have better ultra-endurance capacity, oxidize more fat during endurance exercise, and are more resistant to fat oxidation defects i.e. diet-induced insulin resistance. Several groups have shown that the mRNA and protein transcribed and translated from genes related to transport of fatty acids into the muscle are greater in women than men; however, the mechanism(s) for the observed sex differences in fat oxidation remains to be determined. Muscle biopsies from the vastus lateralis were obtained from moderately active men (N = 12) and women (N = 11) at rest to examine mRNA and protein content of genes involved in lipid oxidation. Our results show that women have significantly higher protein content for tri-functional protein alpha (TFPα), very long chain acyl-CoA dehydrogenase (VLCAD), and medium chain acyl-CoA dehydrogenase (MCAD) (P<0.05). There was no significant sex difference in the expression of short-chain hydroxyacyl-CoA dehydrogenase (SCHAD), or peroxisome proliferator activated receptor alpha (PPARα), or PPARγ, genes potentially involved in the transcriptional regulation of lipid metabolism. In conclusion, women have more protein content of the major enzymes involved in long and medium chain fatty acid oxidation which could account for the observed differences in fat oxidation during exercise.

Effect of thermo-oxidized soybean oil on growth rate and skeletal muscle enzyme activities in rats

Fresh and thermooxidized soybean oil diets were fed to rats for six weeks at two supplementation levels (5% and 15%). Rats fed with thermooxidized oil showed growth depression probably as a result of gross accumulation of decomposition products in the gut of the rats thereby reducing intestinal absorption. Alkaline Phosphatase (ALP) and Acid Phosphatase (ACP) were assayed in the skeletal muscle of the rats. Significant decrease in activity of the enzymes was recorded starting from the second week till the end of the feeding period in the rats fed with 15% thermooxidized oil diet. The decrease in activity of the enzymes might be due to cellular damage caused by peroxides and other products of heated fat which might have inhibited the synthesis of the enzymes or allowed them to leak out of the cell. Analysis of protein content in the skeletal muscle of rats after the feeding experiment shows no significant changes. This study suggests that prolonged consumption of thermally heated Soybean oil at high level could be toxic to the living system.

High-intensity interval training increases SIRT1 activity in human skeletal muscle

The effects of training on silent mating-type information regulator 2 homolog 1 (SIRT1) activity and protein in relationship to peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) and mitochondrial content were determined in human skeletal muscle. Six weeks of high-intensity interval training ( approximately 1 h of 10 x 4 min intervals at 90% peak oxygen consumption separated by 2 min rest, 3 days per week) increased maximal activities of mitochondrial enzymes in skeletal muscle by 28% to 36% (citrate synthase, beta-hydroxyacyl-coenzyme A dehydrogenase, and cytochrome c oxidase subunit IV) and PGC-1alpha protein (16%) when measured 4 days after training. Interestingly, total muscle SIRT1 activity (31%) and activity per SIRT1 protein (58%) increased despite decreased SIRT1 protein (20%). The present data demonstrate that exercise-induced mitochondrial biogenesis is accompanied by elevated SIRT1 activity in human skeletal muscle.

Biochemical markers of muscular damage

Muscle tissue may be damaged following intense prolonged training as a consequence of both metabolic and mechanical factors. Serum levels of skeletal muscle enzymes or proteins are markers of the functional status of muscle tissue, and vary widely in both pathological and physiological conditions. Creatine kinase, lactate dehydrogenase, aldolase, myoglobin, troponin, aspartate aminotransferase, and carbonic anhydrase CAIII are the most useful serum markers of muscle injury, but apoptosis in muscle tissues subsequent to strenuous exercise may be also triggered by increased oxidative stress. Therefore, total antioxidant status can be used to evaluate the level of stress in muscle by other markers, such as thiobarbituric acid-reactive substances, malondialdehyde, sulfhydril groups, reduced glutathione, oxidized glutathione, superoxide dismutase, catalase and others. As the various markers provide a composite picture of muscle status, we recommend using more than one to provide a better estimation of muscle stress.

Myocyte Androgen Receptors Increase Metabolic Rate and Improve Body Composition by Reducing Fat Mass

Testosterone and other androgens are thought to increase lean body mass and reduce fat body mass in men by activating the androgen receptor. However, the clinical potential of androgens for improving body composition is hampered by our limited understanding of the tissues and cells that promote such changes. Here we show that selective overexpression of androgen receptor in muscle cells (myocytes) of transgenic male rats both increases lean mass percentage and reduces fat mass. Similar changes in body composition are observed in human skeletal actin promoter driving expression of androgen receptor (HSA-AR) transgenic mice and result from acute testosterone treatment of transgenic female HSA-AR rats. These shifts in body composition in HSA-AR transgenic male rats are associated with hypertrophy of type IIb myofibers and decreased size of adipocytes. Metabolic analyses of transgenic males show higher activity of mitochondrial enzymes in skeletal muscle and increased O(2) consumption by the rats. These results indicate that androgen signaling in myocytes not only increases muscle mass but also reduces fat body mass, likely via increases in oxidative metabolism.

Adiponectin and AdipoR1 regulate PGC-1α and mitochondria by Ca2+ and AMPK/SIRT1

Adiponectin is an anti-diabetic adipokine. Its receptors possess a seven-transmembrane topology with the amino terminus located intracellularly, which is the opposite of G-protein-coupled receptors. Here we provide evidence that adiponectin induces extracellular Ca(2+) influx by adiponectin receptor 1 (AdipoR1), which was necessary for subsequent activation of Ca(2+)/calmodulin-dependent protein kinase kinase beta (CaMKKbeta), AMPK and SIRT1, increased expression and decreased acetylation of peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha), and increased mitochondria in myocytes. Moreover, muscle-specific disruption of AdipoR1 suppressed the adiponectin-mediated increase in intracellular Ca(2+) concentration, and decreased the activation of CaMKK, AMPK and SIRT1 by adiponectin. Suppression of AdipoR1 also resulted in decreased PGC-1alpha expression and deacetylation, decreased mitochondrial content and enzymes, decreased oxidative type I myofibres, and decreased oxidative stress-detoxifying enzymes in skeletal muscle, which were associated with insulin resistance and decreased exercise endurance. Decreased levels of adiponectin and AdipoR1 in obesity may have causal roles in mitochondrial dysfunction and insulin resistance seen in diabetes.

PGC-1α is required for training-induced prevention of age-associated decline in mitochondrial enzymes in mouse skeletal muscle

The aim of the present study was to test the hypothesis that exercise training prevents an age-associated decline in skeletal muscle mitochondrial enzymes through a PGC-1α dependent mechanism. Whole body PGC-1α knock-out (KO) and littermate wildtype (WT) mice were submitted to long term running wheel exercise training or a sedentary lifestyle from 2 to 13 month of age. Furthermore, a group of approximately 4-month-old mice was used as young untrained controls. There was in both genotypes an age-associated ∼30% decrease in citrate synthase (CS) activity and superoxide dismutase (SOD)2 protein content in 13-month-old untrained mice compared with young untrained mice. However, training prevented the age-associated decrease in CS activity and SOD2 protein content only in WT mice, but long term exercise training did increase HKII protein content in both genotypes. In addition, while CS activity and protein expression of cytc and SOD2 were 50–150% lower in skeletal muscle of PGC-1α mice than WT mice, the expression of the pro-apoptotic protein Bax and the anti-apoptotic Bcl2 was ∼30% elevated in PGC-1α KO mice. In conclusion, the present findings indicate that PGC-1α is required for training-induced prevention of an age-associated decline in CS activity and SOD2 protein expression in skeletal muscle.

Antioxidant enzymes in skeletal muscle and their modulation by alcohol and the dehydrogenase inhibitors 4-methylpyrazole and cyanamide

Antioxidant enzymes in skeletal muscle and their modulation by alcohol and the dehydrogenase inhibitors 4-methylpyrazole and cyanamide

Fate of transgenic DNA and evaluation of metabolic effects in goats fed genetically modified soybean and in their offsprings

The presence of DNA fragments in blood and milk from goats fed conventional (control) or Roundup Ready® soybean meal solvent extracted (s.e.; treated) was investigated by using a polymerase chain reaction approach. The same investigation was carried out on blood, skeletal muscle and organs from kids of both groups fed only dams’ milk until weaning. Moreover, the possible effects on cell metabolism were evaluated by determination of several specific enzymes in serum, heart, skeletal muscle, liver and kidney. Fragments of the multicopy chloroplast (trnL) gene were found in blood and milk samples from goats of both groups. In kids, the chloroplast fragments were found in samples of both groups. In samples, which proved positive for the presence of chloroplast DNA, fragments of the specific soybean single copy gene (lectin) were detected in several blood and milk samples. The same fragment was also found in control and treated groups of kids. Transgenic fragments were not found in those samples, which were found positive for chloroplast fragments of control groups of either goats or kids. On the contrary, in blood and milk of treated goats, fragments both of the 35S promoter and the CP4 epsps gene were detected. These fragments were also found in treated kids with a significant detection of the 35S promoter in liver, kidney and blood, and of the CP4 epsps gene fragment in liver, kidney, heart and muscle. A significant increase in lactic dehydrogenase, mainly concerning the lactic dehydrogenase-1 isoenzyme was found in heart, skeletal muscle and kidney of treated kids, thus suggesting a change in the local production of the enzyme. Finally, no significant differences were detected concerning kid body and organ weight.

Dietary supplementation of old mice with flavonoid dihydroquercetin causes recovery of the mitochondrial enzyme activities in skeletal muscles

The effect of a potent antioxidant, flavonoid dihydroquercetin on the activity of three mitochondrial enzymes in mouse skeletal muscles has been investigated. An ability of this substance to restore the activity of mitochondrial enzymes in old animals was demonstrated. The activities of citrate synthase, NADHcoenzymeQ1-oxidoreductase (complex 1) and cytochromc-oxidase (complex 4) were assessed using spectro-photometric analysis in a quadriceps muscle homogenate. It was shown that the citrate synthase activity decreased moderately and the activities of complexes 1 and 4 in skeletal muscles dropped significantly in old mice. Supplementation of drink water with dihydroquercetin for a few weeks led to an increase of citrate synthase and complex 1 activity (P < 0.1) in muscles of old animals. Activity of complex 4 returned to the level found in the tissue of young mice. Maximal activity of citrate synthase and complex 1 was found in muscles of young mice. Sensitivity of NADH-coenzymeQ1-oxidoreductase to a specific inhibitor rotenone differed in all three groups of mice. Young and old mice exhibited about 95% and 84% of the total sensitivity, respectively, while in old mice receiving dihydroquercetin the sensitivity of complex 1 to the inhibitor increased up to 98%. The biochemical alterations entailed an increase in animals’ mobility as well as an improvement of fur and skin condition. Fatty acid composition of homogenate in muscle tissue of all three groups was also investigated. A reliable decline of the amount of linoleic acid and an increase in stearic and docosanoic acid contents as well as an increase of total amount of fatty acids in muscles of old mice were found. Statistically significant changes in fatty acid composition in muscles of old mice in the control group and in old mice receiving antioxidant were not observed.

Effect of a cyclooxygenase-2 inhibitor on postexercise muscle protein synthesis in humans

Nonselective blockade of the cyclooxygenase (COX) enzymes in skeletal muscle eliminates the normal increase in muscle protein synthesis following resistance exercise. The current study tested the hypothesis that this COX-mediated increase in postexercise muscle protein synthesis is regulated specifically by the COX-2 isoform. Sixteen males (23 +/- 1 yr) were randomly assigned to one of two groups that received three doses of either a selective COX-2 inhibitor (celecoxib; 200 mg/dose, 600 mg total) or a placebo in double-blind fashion during the 24 h following a single bout of knee extensor resistance exercise. At rest and 24 h postexercise, skeletal muscle protein fractional synthesis rate (FSR) was measured using a primed constant infusion of [(2)H(5)]phenylalanine coupled with muscle biopsies of the vastus lateralis, and measurements were made of mRNA and protein expression of COX-1 and COX-2. Mixed muscle protein FSR in response to exercise (P < 0.05) was not suppressed by the COX-2 inhibitor (0.056 +/- 0.004 to 0.108 +/- 0.014%/h) compared with placebo (0.074 +/- 0.004 to 0.091 +/- 0.005%/h), nor was there any difference (P > 0.05) between the placebo and COX-2 inhibitor postexercise when controlling for resting FSR. The COX-2 inhibitor did not influence COX-1 mRNA, COX-1 protein, or COX-2 protein levels, whereas it did increase (P < 0.05) COX-2 mRNA (3.0 +/- 0.9-fold) compared with placebo (1.3 +/- 0.3-fold). It appears that the elimination of the postexercise muscle protein synthesis response by nonselective COX inhibitors is not solely due to COX-2 isoform blockade. Furthermore, the current data suggest that the COX-1 enzyme is likely the main isoform responsible for the COX-mediated increase in muscle protein synthesis following resistance exercise in humans.

The Addition of Choline to Parenteral Nutrition

Choline is a quaternary amine endogenously synthesized from the amino acid methionine or absorbed via the portal circulation. It is ubiquitous in the diet, although it has a greater presence in organ meats. Choline is an essential component of all cell membranes, and has been considered a required dietary nutrient since 1998 by the US Institute of Medicine's Food and Nutrition Board. Choline is necessary for DNA repair, mediated by its role as a methyl donor. It also serves as the precursor for the neurotransmitter acetylcholine. Evidence has accumulated that hepatic steatosis, which occurs during parenteral nutrition therapy, develops as a result of choline deficiency because endogenous production of choline from parenterally infused methionine is deficient. In addition, memory deficits and skeletal muscle abnormalities have been described, and choline deficiency appears to activate cellular apoptosis. Provision of intravenous choline ameliorates hepatic steatosis associated with parenteral nutrition infusion.

The response of human skeletal muscle tissue to hypoxia.

Hypoxia refers to environmental or clinical settings that potentially threaten tissue oxygen homeostasis. One unique aspect of skeletal muscle is that, in addition to hypoxia, oxygen balance in this tissue may be further compromised when exercise is superimposed on hypoxia. This review focuses on the cellular and molecular responses of human skeletal muscle to acute and chronic hypoxia, with emphasis on physical exercise and training. Based on published work, it is suggested that hypoxia does not appear to promote angiogenesis or to greatly alter oxidative enzymes in skeletal muscle at rest. Although the HIF-1 pathway in skeletal muscle is still poorly documented, emerging evidence suggests that muscle HIF-1 signaling is only activated to a minor degree by hypoxia. On the other hand, combining hypoxia with exercise appears to improve some aspects of muscle O(2) transport and/or metabolism.

Exercise training from late middle age until senescence does not attenuate the declines in skeletal muscle aerobic function

We previously showed that 7 wk of treadmill exercise training in late-middle-aged rats can reverse the modest reductions in skeletal muscle aerobic function and enzyme activity relative to values in young adult rats (Exp Physiol 93: 863-871, 2008). The purpose of the present study was to determine whether extending this training program into senescence would attenuate the accelerated decline in the muscle aerobic machinery normally seen at this advanced age. For this purpose, 29-mo-old Fisher 344 Brown-Norway rats underwent 5 or 7 mo of treadmill exercise training. Training resulted in greater exercise capacity during an incremental treadmill exercise test and reduced percent body fat in 34- and 36-mo-old rats and improved survival. Despite these benefits at the whole body level, in situ muscle aerobic capacity and muscle mass were not greater in the trained groups at 34 mo or 36 mo of age. Similarly, the trained groups did not have higher activities of citrate synthase (CS) or Complex IV in homogenates of either the plantaris (fast twitch) or the soleus (slow twitch) muscles at either age. Finally, protein expression of CS (a marker of mitochondrial content) and peroxisome proliferator-activated receptor-gamma coactivator-1 (relating to the drive on mitochondrial biogenesis) were not higher in the trained groups. Therefore, although treadmill training from late middle age into senescence had significant benefits on running capacity, survival, and body fat, it did not prevent the declines in muscle mass, muscle aerobic capacity, or mitochondrial enzyme activities normally seen across this age, revealing a markedly diminished plasticity of the aerobic machinery in response to endurance exercise at advanced age.

Does training fasted make you fast?

exercise training allows one to perform the same absolute exercise bout with less of a challenge to homeostasis. The metabolic adaptations include increases in the activity of tricarboxylic acid (TCA) cycle enzymes such as citrate synthase and the β-oxidation enzyme β-hydroxyacyl-CoA dehydrogenase

Transcriptomic signature of performance efficiency in finishing beef cattle

Metabolic redundancies and inefficiencies at the molecular level associated with feed efficiency (FE) and residual feed intake (RFI) of food animals may be ascertained by gene expression (GE) profiling. The objective of this study was to examine relationships between GE (mRNA abundance) of fatty acid synthase (FAS), PPARα, PPAR γ2, carnitine palmitoyl transferase (CPT‐1b), leptin, uncoupling protein 2 (UCP‐2), ubiquitin conjugating enzyme (E2) and polyubiquitin (PQ) genes in skeletal muscle (SKM) and adipose tissue (AT) with FE and RFI in finishing cattle. Crossbred cattle (bulls, 8; steers, 8) were placed on a feedlot diet and AT and SKM biopsies were taken prior to completion of the trial. Gene expression was determined with real time RT‐PCR. Adipose FAS, leptin and PPARγ2 GE were unrelated to RFI. SKM UCP‐2 and E‐2 but not CPT‐1b, PPARα and PQ GE were correlated with RFI (P&lt;.05). AT leptin GE was higher (P&lt;.05) while SKM UCP‐2 GE was lower (P&lt;.05) in bulls than steers. While PQ GE was not correlated with RFI it was highly correlated (P&lt;.01) with E2 GE. Results indicate that AT genes for fat deposition are likely minimally related to RFI and FE, while SKM GE associated with mitochondrial metabolism and protein turnover are correlated with RFI. The transcriptomic signature for efficiency in beef cattle appears more related to SKM than AT metabolism.

PPAR‐alpha agonist increases skeletal muscle carnitine palmitoyltransferase‐1 activity and fatty acid oxidation in obese insulin‐resistant monkeys

The selective PPAR‐alpha agonist K‐111 (Kowa Co. Ltd., Tokyo, Japan) decreases plasma triglycerides and improves insulin sensitivity in obese, insulin‐resistant rhesus monkeys. The purpose of this study was to determine whether K‐111 improves skeletal muscle fatty acid oxidation and enzymes involved in fatty acid metabolism. Five obese, insulin‐resistant adult monkeys were studied at baseline and again after treatment with K‐111 at 3 mg/kg μday for 7 weeks. Acyl‐CoA synthase (ACS), carnitine palmitoyltransferase‐1 (CPT‐1), β‐hydroxy‐acyl CoA dehydrogenase ( β‐HAD), citrate synthase (CS) and total fatty acid oxidation were measured in skeletal muscle homogenates at baseline and following K‐111. CPT‐1 activity significantly increased (0.012 ± 0.004 vs. 0.019 ± 0.004 pmol/min μ;mg protein, p&lt;0.05) and total fatty acid oxidation tended to increase (2.1 ± 0.6 vs. 4.0 ± 1.1 pmol/min μmg protein, p&lt;0.07) following treatment. ACS activity (128 ± 25 vs. 180 ± 11 pmol/min μmg protein), β‐HAD activity (0.182 ± 0.05 vs. 0.190 ± 0.03) and CS activity (0.108 ± 0.02 vs. 0.116 ± 0.01 µmol/min μmg protein) were not significantly affected by treatment. The change in total fatty acid oxidation was associated with the change in ß‐HAD and CS activity (p&lt;0.01) but not to CPT‐1 activity. These results suggest that the mechanism by which PPAR‐alpha agonist treatment improves fatty acid oxidation is through changes in ß‐HAD and CS activity.

Activities of selected antioxidative, hydrolytic and hexose monophosphate shunt enzymes of skeletal muscle in neuromuscular diseases

Acta Neurologica ScandinavicaVolume 69, Issue S98 p. 176-177 Activities of selected antioxidative, hydrolytic and hexose monophosphate shunt enzymes of skeletal muscle in neuromuscular diseases V. V. Myllylä, V. V. Myllylä Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorT. E. S. Takala, T. E. S. Takala Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorU. Tolonen, U. Tolonen Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorA. Salminen, A. Salminen Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorM. Kihlström, M. Kihlström Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorV. Vihko, V. Vihko Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this author V. V. Myllylä, V. V. Myllylä Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorT. E. S. Takala, T. E. S. Takala Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorU. Tolonen, U. Tolonen Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorA. Salminen, A. Salminen Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorM. Kihlström, M. Kihlström Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this authorV. Vihko, V. Vihko Departments of Neurology and Clinical Chemistry, University of Oulu Oulu; Department of Cell Biology, University of Jyväskylä, Jyväskylä, FinlandSearch for more papers by this author First published: April 1984 https://doi.org/10.1111/j.1600-0404.1984.tb02425.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume69, IssueS98April 1984Pages 176-177 RelatedInformation