bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sex differences in the effects of stressful life events on changes in smoking status
Authors: McKee Sherry A. , Maciejewski Paul K. , Falba Tracy , Mazure Carolyn M. 
Published: May 2003

ABSTRACTAims  Stressful life events known to be associated with substance use were examined to determine if there were sex‐specific responses to stress resulting in changes in smoking status.Participants and measurements  A community‐based sample of ever smokers from the Americans’ Changing Lives study (n = 1512, 45% female based on sample weights) was used to examine the interactive effects of sex and stressful life events on the likelihood of two outcomes; relapse among former smokers and failure to quit among current smokers. Logistic regression procedures were used to calculate odds ratios. Factors known to be associated with smoking status (e.g. depression, self‐esteem, social support) were assessed as control variables.Findings  In the sample of former smokers (n = 729) interpersonal loss events were associated with continued abstinence, whereas change of residence and adverse financial events were associated with increased occurrence of relapse. Women were more likely than men to relapse in response to a financial event. In the sample of current smokers (n = 783), financial events were associated with continued smoking, whereas health events were associated with increased likelihood of quitting. Women were more likely than men to continue smoking in the presence of an adverse financial event and less likely than men to quit in response to an adverse health event.Conclusions  Overall, stressful life events appear to have a greater deleterious effect on continued abstinence and the ability to quit smoking for women when compared to men. In particular, health and financial events are important risk factors for women and tobacco use.
Prevalence of alcohol use disorders and associated factors: a population‐based study using AUDIT in southern Brazil
Authors: Mendoza‐Sassi Raúl A. , Béria Jorge U. 
Published: May 2003

ABSTRACTAims  To assess the prevalence of potential alcohol use disorders and associated factors using the Alcohol Use Disorders Identification Test (AUDIT).Design  Cross‐sectional study.Setting  A town in southern Brazil.Participants  A representative sample of 1260 people aged 15 and over.Measurements  Demographic, socioeconomic, smoking habit and mental health data were collected. Logistic regression was used in the multivariate analysis, and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.Findings  Overall prevalence of alcohol use disorder was 7.9%, with 14.5% prevalence among men and 2.4% among women. The risk of alcohol misuse increased across social class (P linear trend = 0.03) and compared with the highest classes (A and B), groups C through E had ORs of 1.48, 1.51 and 2.36, respectively. Males had an OR of 6.89 (CI 3.61–13.16) compared with women. A linear trend was found (P = 0.001) between smoking categories, and smokers (OR 3.27; CI 1.91–5.58) and ex‐smokers (OR 1.30; CI 0.56–2.98) were at higher risk than non‐smokers. Those with minor psychiatric disorders had a 2.48 OR (CI 1.35–4.56) of presenting a positive test.Conclusions  The AUDIT detected a high prevalence of potential alcohol use disorders in the population sampled. Those identified are potential targets for preventive measures implemented through health policies.
Lowering of interstitial fluid pressure in rat trachea after substance P alone and in combination with calcitonin gene‐related peptide
Authors: Gjerde E.‐A. B. , Karlsen T. V. , Reed R. K. 
Published: May 2003

AbstractNeurogenic inflammation is mediated following a release of sensory neuropeptides including calcitonin gene‐related peptide (CGRP) and substance P (SP). The release of peptides can be mediated chemically with capsaicin, or electrically by stimulation of the vagal nerve, both inducing vasodilation, plasma protein extravasation and lowering of interstitial fluid pressure (Pif) which will contribute to the enhancement of oedema formation.Aim: Lowering of Pif has previously been demonstrated following intravenous (i.v.) treatment with CGRP, but it was not possible to demonstrate that SP had this effect under the same condition.Methods: Micropuncture measurements of Pif in the submucosa, without opening of the trachea, was conducted on rats anaesthetized with pentobarbital sodium (50 mg kg−1) and cardiac arrest was induced with i.v. KCl.Results: P
if in vehicle‐treated animal averaged −1.7 ± 0.4 (SD) mmHg (n = 9). Intravenous injection of SP induced significant lowering of Pif compared with control, both at low dose (0.47 nmol kg−1 body weight) with 1 min distribution time (P < 0.007, −4.2 ± 2.3 mmHg) and at high dose with seconds of distribution time (P < 0.03, −4.2 ± 1.6 mmHg). The same response was observed after treatment with SP co‐injected with CGRP.Conclusions:  Substance P alone or in combination with CGRP is able to induce a rapid lowering of Pif showing that this peptide is a potent agent in increasing the hydrostatic driving pressure initially transporting fluid into the tissue during an acute inflammatory reaction.
Ischaemic preconditioning alters the energy metabolism and protects the ischaemic myocardium in a stepwise fashion
Authors: Kavianipour M. , Ronquist G. , Wikström G. , Waldenström A. 
Published: May 2003

AbstractAims and Methods: Recently it was suggested that ischaemic preconditioning (IP) protects the myocardium in a graded pattern as assessed by myocardial infarct size estimation. Using tissue biopsies we investigated the impact of the proposed graded pattern of protection on myocardial energy state in an open‐chest porcine model of IP with either one (1xIP) or four (4xIP) episodes of preconditioning. Furthermore, we evaluated the relationship between interstitial energy‐related metabolite levels obtained by the microdialysis technique and the degree of subsequent ischaemic insult.Results: During the long ischaemia the difference between pre‐ischaemic and post‐ischaemic total adenylate pools and the sum of adenylate breakdown products (adenosine, inosine and hypoxanthine) as well as tissue lactate levels appeared as follows: non‐IP > 1xIP > 4xIP (P < 0.05). Moreover interstitial peak levels of lactate, hypoxanthine and taurine displayed a graded pattern analogous to the development of ischaemic damage, where non‐IP > 1xIP > 4xIP.Conclusions: We present for the first time concordant energy metabolic and morphometric data in support of IP being a stepwise phenomenon for protection of the ischaemic myocardium. Furthermore, IP resulted in proportionally higher levels of hypoxanthine (relative to inosine) in the ischaemic myocardium, suggesting a different handling of adenine nucleotide breakdown products in the IP myocardium.
Oxygen dependency of the adrenergic Na/H exchange in rainbow trout erythrocytes is diminished by a hydroxyl radical scavenger
Authors: Nikinmaa M. , Bogdanova A. , Lecklin T. 
Published: May 2003

AbstractAim: Potassium transport via the potassium chloride cotransporter in rainbow trout erythrocytes is increased by high oxygen tension. It appears that the effect of oxygen is mediated by reactive oxygen species, especially hydroxyl radicals. In contrast, the activity of adrenergically stimulated sodium proton exchange decreases with increasing oxygen tension. As available data suggest that the two transporters are regulated reciprocally, the present study was undertaken to evaluate, if hydroxyl radicals may inhibit sodium transport via the adrenergically stimulated sodium proton exchanger.Methods: The effects of the hydroxyl radical scavenger, 2 mm mercaptopropionyl glycine (MPG), on the activity of the adrenergically activated sodium proton exchange in rainbow trout erythrocytes were examined by measuring unidirectional sodium flux, using radioactive isotope, and cellular water content.Results: The activity of the sodium proton exchange increased with decreasing oxygen tension after adrenergic stimulation. When MPG was present during incubation, there was no statistically significant effect of oxygen tension on the adrenergically stimulated sodium proton exchange, whereby the activity of the transporter at atmospheric oxygen tension was markedly higher in the presence than in the absence of MPG. In the absence of adrenergic stimulation, MPG did not influence the transporter activity significantly at any oxygen tension.Conclusion: The data suggest that hydroxyl radicals are involved in the inhibition of the adrenergically stimulated sodium proton exchange at elevated oxygen tensions.
Interaction of fibre type, potentiation and fatigue in human knee extensor muscles
Authors: Hamada T. , Sale D. G. , MacDougall J. D. , Tarnopolsky M. A. 
Published: May 2003

AbstractAim: To examine the effect of fibre type on potentiation and fatigue.Methods: Young men (n = 4 per group) with a predominance of type I [61.4 ± 6.9% (SD), group I (GI)] or type II [71.8 ± 9.2%, group II (GII)] fibres in vastus lateralis, performed a fatigue protocol of sixteen 5‐s maximal voluntary isometric contractions (MVCs) of the right knee extensors. Maximal twitches and corresponding muscle action potentials (M‐waves) were evoked before the first MVC, during the 3‐s rest period after each MVC and at intervals during the 5‐min recovery period after the last MVC.Results:  Group II [49.3 ± 2.6% (SE)] had a greater decrease in MVC force than GI (22.8 ± 6.2%) during the fatigue protocol. Group II (126.4 ± 13.6%) showed greater twitch force potentiation early in the fatigue protocol than GI (38.2 ± 2.3%), but greater depression at the end (33.7 ± 13.7% vs.17.4 ± 3.4%). Twitch time‐to‐peak torque (TPT) and half relaxation time (HRT) initially decreased but then increased as the fatigue protocol progressed; GII had a greater increase in HRT. During a 5‐min recovery period twitch force increased above the prefatigue level and remained so until the end of the recovery period; the pattern was similar in GI and GII. Twitch TPT and HRT remained elevated during recovery. M‐wave area increased throughout the fatigue protocol and the first part of recovery before returning to baseline values in GII, whereas there were no significant changes in GI. The interaction between potentiation and fatigue was amplified in GII early in the fatigue protocol with concurrently greater twitch and M‐wave potentiation, and greater MVC force decrease and HRT increase. Late in the protocol, GII had a greater decrease in twitch and MVC force combined with greater M‐wave potentiation.Conclusion: It is concluded that fibre type distribution influences potentiation and fatigue of the twitch, and potentiation of the M‐wave during fatiguing exercise.
Dose‐dependent effects of acute exercise on PKC levels in rat heart: is PKC the heart's prophylactic?
Authors: Carson L. D. , D. H. Korzick 
Published: May 2003

AbstractEpidemiological studies have demonstrated that chronic exercise is cardioprotective, and recent evidence from our laboratory suggests a key role for protein kinase C (PKC)‐dependent pathways, at least in part, as a cellular basis for this response. However, the dose–response relationship linking exercise volume and the time course of isoform‐specific PKC activation are poorly understood.Aim:  The purpose of this investigation was to determine the effects of acute exercise of varying durations on PKC subcellular distribution and phosphorylation in the rat left ventricle.Methods:  Adult (5 months) male Fischer‐344 more rats were subjected to a single bout (OB) or 7 days (SB) of treadmill running (n = 6/group; 23 m min−1, 20 min), and compared with sedentary controls (SED; n = 8). Hearts were isolated immediately after [early window (EW); n = 3/group] or 24 h after the last exercise bout [late window (LW); n = 3/group] in OB and SD, respectively. Total PKC and subcellular distribution for the α, δ, ɛ, βI, and βII isoforms, as well as phosphorylated (phospho‐) PKCɛ (pSer729), PKCα (pSer657) and PKCδ (pThr507) levels were assessed by western blotting. Protein kinase Cɛ and PKCα mRNA levels were assessed by real time polymerase chain reaction.Results: Following OB, PKCβI protein levels were reduced, while total phospho‐PKCɛ (pSer729), PKCα (pSer657) and PKCδ (pThr507) levels were increased during EW (P < 0.05). Interestingly, total PKCδ (31%) and membrane‐associated PKCα (24%) levels decreased from EW to LW (P < 0.05). In contrast, SB yielded chronic increases in total PKCɛ (80.5%) levels and PKCδ (20.0%) levels (P < 0.03), with reversal of effects on phospho‐PKCɛ (Ser729), phospho‐PKCα (Ser657) and phospho‐PKCδ (Thr507) levels observed with OB. Reductions in total phospho‐PKCα (Ser657) persisted at SB (26.1%; P < 0.02). Interestingly, mRNA levels for PKCɛ were significantly increased following SB while PKCα mRNA levels were reduced, respectively.Conclusion:  These data suggest that divergent patterns of PKC activation occur following OB and SB at both the transcriptional and translational levels. That similar patterns of PKC translocation are observed in experimental models of ischaemic preconditioning and genetic PKC manipulation provide evidence for a dose‐dependent cardioprotective phenotype induced by physical activity.
Age, cell signalling and cardioprotection
Authors: Taylor R. P. , Starnes J. W. 
Published: May 2003

AbstractFor many years investigators have been researching methods of preconditioning the myocardium against ischaemia‐induced damage; however, a majority of this research has been carried out in young animals and cells. Normal ageing is accompanied by changes in the human myocardium that decrease its capacity to tolerate and respond to various forms of stress. Also, the likelihood of experiencing an ischaemic stress and other cardiovascular complications increases as an individual ages; therefore, an aged population would benefit most from cardioprotective treatments. Methods currently known to provide cardioprotection (or preconditioning) include exercise, heat stress, oxidative stress, brief ischaemia, stretch and certain pharmacological interventions. It is unclear whether the aged myocardium can adapt to a preconditioning stimulus; however, many researchers have observed age‐related alterations in the expression and activation of proteins key to the cardioprotective process. These proteins include heat shock protein 70 (HSP70), nitric oxide synthase (NOS), the sodium‐hydrogen exchanger (NHE), and the mitogen‐activated protein (MAP) kinases c‐Jun N‐terminal Kinase (JNK), extracellular signal‐regulated kinase (ERK), and p38. Therefore, the purpose of the current review will be to outline the current knowledge of these cardioprotective agents in an aged myocardium. Interactions among the cardioprotective agents outlined herein suggest that age‐related changes in the myocardium will need to be better understood before cardioprotective interventions that have been proved effective in young animals can be applied to an aged human population.
Phorid parasitoids affect foraging activity ofSolenopsis richteriunder different availability of food in Argentina
Authors: Folgarait Patricia J. , Gilbert Lawrence E. 
Published: May 2003

Summary1. In Argentina, six species ofPseudacteonparasitoids (Phoridae) attackSolenopsis richteri, one of the two species of South American fire ant that are exotic pests in North America.2. The presence of thesePseudacteonspecies significantly reduces the number of ants at food resources in the field, as well as foraging activity generally.3. SomePseudacteonnot only attack ants walking on trails or at feeding sites, but also at mound entrances, inhibiting workers from leaving to forage.4. The average size of foraging ants (which prescribes their suitability as hosts) decreased in the presence of phorids.5. The number of attacking phorids was correlated positively with the number of ants walking towards the food on the trail before the attack.6.Solenopsis richteriworkers responded to manipulations of food size and presence or absence of parasitoids in a risk‐adjusting way, i.e. although more foragers were recruited to larger food items, attacking phorids reduced ant foraging activity by the same factor regardless of the size of the food offered.7. The data suggest thatS. richtericolonies juggle the needs to harvest food efficiently, reduce competition, and avoid excess risks from parasitoids in complex ways.
Windows of opportunity and the temporal structuring of foraging activity in a desert solitary bee
Authors: Stone Graham N. , Gilbert Francis , Willmer Pat. , Potts Simon , Semida Fayez , Zalat Samy. 
Published: May 2003

Summary1. Females of the desert solitary bee Anthophora pauperata collect nectar and pollen almost exclusively from Alkanna orientalis (Boraginaceae). The bee and plant are found together in the early spring, living in the bottom of steep‐sided wadis (dry river valleys) at an altitude of 1500 m in Egyptian Sinai.2. Female A. pauperata showed clear morning and afternoon peaks in foraging activity, separated by a 2–3 h midday period spent in their underground nests. This study analyses the following in order to identify the factors structuring this daily pattern: thermal aspects of the bee and its environment, temporal patterns of resource provision by the plant, and female nectar and pollen foraging behaviour.3. Although A. pauperata can generate substantial heat endothermically, morning and evening ambient temperatures well below 10 °C defined a thermal window within which foraging occurred. Maximum air temperatures were moderate (25–30 °C), and examination of the physiology and behaviour of A. pauperata suggests that the midday reduction in flight activity was not due to thermal constraints.4. Alkanna orientalis produces protandrous hermaphroditic flowers. Female A. pauperata collected pollen from male‐phase flowers and harvested nectar preferentially from female‐phase flowers. Although the nectar standing crop was relatively constant throughout the day, pollen availability peaked strongly in the early afternoon.5. Female A. pauperata visited young male‐phase flowers as soon as they opened, generating an early afternoon peak in pollen foraging activity and depleting the pollen standing crop rapidly. A morning peak in pollen foraging occurred when females gleaned remnant pollen from flowers that had opened the previous day. Pollen availability in the morning was far lower than in the early afternoon, and the time taken to collect a full pollen load in the morning was significantly longer. Collection of pollen in the morning despite very low resource availability suggests that pollen may be a limiting resource for A. pauperata.6. In contrast to many existing examples of bimodal activity patterns in highly endothermic bees, the bimodal activity patterns of female A. pauperata appear to be driven not by thermal considerations but by daily patterns of pollen release from its principal food source.
The effects of parasitoid fecundity and host taxon on the biological control of insect pests: the relationship between theory and data
Authors: Lane S. D. , Mills N. J. , Getz W. M. 
Published: May 2003

Summary1. A simple, intuitive argument and the tenets of the biological control literature both suggest that, in general, parasitoids with a greater fecundity will provide better control of their hosts, and will thus be better biological control agents.2. A model of host‐parasitoid dynamics, based on the standard Thompson–Nicholson–Bailey approach and incorporating the effects of parasitoid fecundity‐limitation and host density‐dependence, also indicates that as parasitoid fecundity decreases so does local stability and the degree of host suppression.3. A taxonomically diverse data set obtained from the biological control record failed to support this theoretical prediction, but at the same time indicated a strong effect of host taxon on the outcome of biological control.4. The hypothesis that the fecundity of parasitoids is correlated positively with their ability to suppress host populations is supported by data exclusively from the host order Lepidoptera.5. Possible explanations for the divergence between the fecundity‐limitation hypothesis and the complete data set include: the ability of parasitoids to provide long‐term control of pests without the presence of a stable host–parasitoid equilibrium; differences between the concepts of successful control in theory and practice; evolutionary trade‐offs between fecundity and other parasitoid life‐history features, such as search efficiency, leading to better pest control by parasitoids with low fecundity; and differing windows of vulnerability to parasitoid attack between host taxa.
Experimental evidence for predation risk sensitive oviposition by a mosquito, Culiseta longiareolata
Authors: Stav Gil. , Blaustein Leon. , Margalith Joel. 
Published: May 2003

Summary1. Females should choose to oviposit in habitats where risk of predation and competition are low. The ovipositional responses of a mosquito, Culiseta longiareolata, to a predator and to species sharing the same trophic level as this mosquito (controphic species) were assessed experimentally in outdoor artificial pools.2. The predator, larval Anax imperator, which strongly reduced larval C. longiareolata survival, resulted in a 52% reduction of C. longiareolata egg rafts. The controphic species (primarily Daphnia magna), which had a small but statistically significant negative effect on the survival of C. longiareolata larvae, did not have a statistically significant influence on the number of egg rafts.3. Laboratory trials indicated that only a small fraction of the reduced number of egg rafts seen in predator pools may be due to consumption of the egg rafts by A. imperator.4. The experimental evidence indicates that the reduced number of C. longiareolata egg rafts found in the presence of A. imperator is due largely to oviposition habitat selection, i.e. C. longiareolata females choose pools with low risk of predation for their offspring.