bluuebunny/crossref_metadata_2025 huggingface dataset:
Local co-adaptation leading to a geographical mosaic of coevolution in a social parasite system
Authors: Fischer B. , Foitzik S.
Published: August 2004

The geographical mosaic theory of coevolution predicts differences in the advance or trajectory of the coevolutionary process between local communities due to their composition and the strength of ecological selection pressures through competition and resource availability. In this study, we investigate local co-adaptation in different populations of a social parasite. We conducted cross-fostering experiments to test for interpopulational differences in raiding efficiency between various populations of a slave-making ant and the defence abilities of local hosts. Here, we demonstrate that the success of raids strongly depends on the combination of populations of the parasite Harpagoxenus sublaevis and its host Leptothorax acervorum, indicating very localized coevolution. We found no absolute differences between slave-maker populations; the outcome of an encounter depended more on whether the two opponents occur in sympatry or allopatry. Furthermore, this study supports the results of our earlier work, that the unparasitized English L. acervorum population is most aggressive against the parasite.
Host ecology determines the relative fitness of virus genotypes in mixed-genotype nucleopolyhedrovirus infections
Authors: Hodgson D. J. , Hitchman R. B. , Vanbergen A. J. , Hails R. S. , Possee R. D. , Cory J. S.
Published: August 2004

Mixed-genotype infections are common in many natural host–parasite interactions. Classical kin-selection models predict that single-genotype infections can exploit host resources prudently to maximize fitness, but that selection favours rapid exploitation when co-infecting genotypes share limited host resources. However, theory has outpaced evidence: we require empirical studies of pathogen genotypes that naturally co-infect hosts. Do genotypes actually compete within hosts? Can host ecology affect the outcome of co-infection? We posed both questions by comparing traits of infections in which two baculovirus genotypes were fed to hosts alongside inocula of the same or a different genotype. The host, Panolis flammea, is a herbivore of Pinus sylvestris and Pi. contorta. The pathogen, PfNPV (a nucleopolyhedrovirus), occurs naturally as mixtures of genotypes that differ, when isolated, in pathogenicity, speed of kill and yield. Single-genotype infection traits failed to predict the ‘winning’ genotypes in co-infections. Co-infections infected and caused lethal disease in more hosts, and produced high yields, relative to single-genotype infections. The need to share with nonkin did not cause fitness costs to either genotype. In fact, in hosts feeding on Pi. sylvestris, one genotype gained increased yields in mixed-genotype infections. These results are discussed in relation to theory surrounding adaptive responses to competition with nonkin for limited resources.
Worker reproduction and policing in insect societies: an ESS analysis
Authors: Wenseleers T. , Helanterä H. , Hart A. , Ratnieks F. L. W.
Published: August 2004

Insect societies are vulnerable to exploitation by workers who reproduce selfishly rather than help to rear the queen's offspring. In most species, however, only a small proportion of the workers reproduce. Here, we develop an evolutionarily stable strategy (ESS) model to investigate factors that could explain these observed low levels of reproductive exploitation. Two key factors are identified: relatedness and policing. Relatedness affects the ESS proportion of reproductive workers because laying workers generally work less, leading to greater inclusive fitness costs when within-colony relatedness is higher. The second key factor is policing. In many species, worker-laid eggs are selectively removed or ‘policed’ by other workers or the queen. We show that policing not only prevents the rearing of worker-laid eggs but can also make it unprofitable for workers to lay eggs in the first place. This can explain why almost no workers reproduce in species with efficient policing, such as honeybees, Apis, and the common wasp, Vespula vulgaris, despite relatively low relatedness caused by multiple mating of the mother queen. Although our analyses focus on social insects, the conclusion that both relatedness and policing can reduce the incentive for cheating applies to other biological systems as well.
Comparing phylogenetic signal in intraspecific and interspecific body size datasets
Authors: Ashton K. G.
Published: August 2004

Phylogenetic comparative methods have become a standard statistical approach for analysing interspecific data, under the assumption that traits of species are more similar than expected by chance (i.e. phylogenetic signal is present). Here I test for phylogenetic signal in intraspecific body size datasets to evaluate whether intraspecific datasets may require phylogenetic analysis. I also compare amounts of phylogenetic signal in intraspecific and interspecific body size datasets. Some intraspecific body size datasets contain significant phylogenetic signal. Detection of significant phylogenetic signal was dependant upon the number of populations (n) and the amount of phylogenetic signal (K) for a given dataset. Amounts of phylogenetic signal do not differ between intraspecific and interspecific datasets. Further, relationships between significance of phylogenetic signal and sample size and amount of phylogenetic signal are similar for intraspecific and interspecific datasets. Thus, intraspecific body size datasets are similar to interspecific body size datasets with respect to phylogenetic signal. Whether these results are general for all characters requires further study.
Treatment of hepatitis C virus infection in patients of northern India
Authors: HAZARI SIDHARTHA , PANDA SUBRAT KUMAR , GUPTA SIDDHARTH DATTA , BATRA YOGESH , SINGH RAJBIR , ACHARYA SUBRAT KUMAR
Published: August 2004

Background and Aim:  The purpose of the present study was to evaluate the therapeutic response of north Indian patients with chronic hepatitis C (CH‐C) to two different treatment regimens of interferon and ribavirin.

Methods:  Consecutive patients with a diagnosis of CH‐C attending the Liver Clinic at the All India Institute of Medical Sciences, New Delhi between April 1999 and April 2002 were included in the study. A competitive reverse transcription–polymerase chain reaction (RT‐PCR) method developed in the authors’ laboratory was used for quantification of hepatitis C virus (HCV)‐RNA. Genotyping of HCV was also determined. The clinical, biochemical, virological and histological parameters were used to assess the therapeutic response among a clinical cohort of patients with chronic hepatitis C. They were treated with two different protocols (interferon [IFN]‐α‐2b, 3 million units daily and ribavirin 10.6 mg/kg daily in two divided doses for 6 months or IFN‐α‐2b, 3 million units thrice weekly and ribavirin 10.6 mg/kg daily for 6 months).

Results:  Sixty‐five patients with CH‐C were included in the study. Blood transfusion (n = 28, 43%) and community‐acquired (n = 23, 35%) HCV infections were the commonest. The mean HCV load was high (24.14 ± 12.5 × 108 copies/mL). Genotype 2 and 3 were prevalent in 80% (41/51) of the patients. Forty‐five patients received 3 million units of IFN thrice weekly and 20 received the same dose daily. All received the same dose of ribavirin. A sustained virological response (SVR) of 95% (19/20) was achieved among patients receiving daily IFN, whereas 64.4% (29/45) of those who received IFN thrice weekly had SVR. The virological relapse was significantly lower among patients who received daily IFN than in those treated with thrice weekly IFN (n = 1/20, 5% vs 10/39, 25.6%; P = 0.015). The proportion of patients receiving daily IFN among those achieving SVR (19/48, 40%) was significantly higher than the proportion of patients receiving similar therapy among patients without SVR (1/17, 6%; P = 0.02).

Conclusions:  Transfusion and community‐acquired HCV infection were the major causes of CH‐C. Genotype 2 and 3 HCV were most prevalent among these patients. Despite high viral load, these patients responded well to a combination of daily IFN‐α‐2b and ribavirin.

© 2004 Blackwell Publishing Asia Pty Ltd
Role of additional angiography and chemoembolization in patients with hepatocellular carcinoma who achieved complete necrosis following transarterial chemoembolization
Authors: JANG MYOUNG KUK , LEE HAN CHU , KIM IN SOOK , LIM YOUNG‐SUK , CHUNG YOUNG‐HWA , LEE YUNG SANG , SUNG KYU‐BO , YOON HYUN‐KI , KO GI‐YOUNG , KIM AH YOUNG , SUH DONG JIN
Published: August 2004

Background and Aims:  Although transarterial chemoembolization (TACE) has been reported to have antitumor effects in patients with hepatocellular carcinoma (HCC), optimal time schedules and follow‐up methods have not yet been determined. We therefore prospectively analyzed the effects of additional angiography and chemoembolization on HCC recurrence and survival in patients who underwent TACE and achieved complete necrosis (CN).

Methods:  A total of 68 patients who achieved CN after TACE, as assessed using dynamic computed tomography (CT), were randomized into two groups. Patients in the CT group (n = 34) were followed using dynamic CT every 3 months without any further intervention, whereas patients in the angiography group (n = 34) received additional angiography 1 month after achievement of CN. We compared overall survival and disease‐free survival between the two groups and analyzed the benefit of additional angiography.

Results:  The cumulative recurrence rate did not differ between the angiography and CT groups (55%vs 48% at 12 months and 66%vs 67% at 24 months, P = 0.92). The overall survival rates at 12 and 24 months were 88% and 84% in the angiography group, and 88% and 70% in the CT group, respectively (P = 0.57). Of the 34 patients in the angiography group, 27 (79%) suffered from adverse reactions of additional angiography and subsequent chemoembolization, seven (20.6%) experienced serum bilirubin increases of ≥1 mg/dL over baseline, and two (5.9%) developed renal impairment.

Conclusion:  Additional angiography and chemoembolization did not reduce tumor recurrence or improve patient survival in HCC patients who achieved CN, as assessed using dynamic CT, following TACE.

© 2004 Blackwell Publishing Asia Pty Ltd
Hypergastrinemia after Helicobacter pylori infection is associated with bacterial load and related inflammation of the oxyntic corpus mucosa
Authors: CHUANG CHIAO‐HSIUNG , SHEU BOR‐SHYANG , YANG HSIAO‐BAI , KAO AI‐WEN , CHENG HSIU‐CHI , YAO WEI‐JEN
Published: August 2004

Background and Aim:  Helicobacter pylori infection causes hypergastrinemia. This study aimed to determine the association between serum gastrin and the severity of H. pylori‐related gastric histology.

Methods:  A total of 458 dyspeptic patients were included in this study after the absence of gastric malignancy was confirmed using endoscopy. The gastric specimens of each patient were collected from the antrum and corpus for the analysis of H. pylori‐related histology changes by updated Sydney's system. Before endoscopy, the fasting blood samples were collected for gastrin analysis.

Results:  The H. pylori‐infected patients had higher gastrin levels than those without infection (P = 0.01). Gastrin levels were related to H. pylori density and acute and chronic inflammation scores in the corpus mucosa (P < 0.05), but not in the antral mucosa (P = NS). Gastrin levels were also not related to the presence of gastric atrophy. Multivariate regression showed that the gastrin level was only related to acute corpus inflammation. However, in the patients without infection, the gastrin level was also associated with acute corpus inflammation. Nevertheless, the patients with denser H. pylori infection were more likely to have acute corpus gastritis than those with lighter H. pylori infection, and thus presented with higher gastrin levels (P < 0.05).

Conclusions:  The increased level of gastrin of serum after H. pylori infection was associated with acute inflammation in the gastric corpus mucosa, but not in the antral mucosa. Denser H. pylori infection causes more severe corpus gastritis and thus may lead to a higher fasting level of gastrin of serum.
Significance of three‐dimensional computed tomography in a very old patient with sigmoid volvulus
Authors: Ebihara Satoru , Okazaki Tatsuma , Takahashi Hidenori , Kanda Akio , Tsuboi Masahiro , Sasaki Hidetada
Published: August 2004

With an increase in the aged population, a greater opportunity to face sigmoid volvulus is expected. We report sigmoid volvulus in a 90‐year‐old man with a 4‐day history of increasing abdominal discomfort and distension. The reconstructed three‐dimensional computed tomography (CT) clearly revealed the presence of sigmoid volvulus and the location of the twist. Using colonoscopy, the patient was successfully decompressed. Three‐dimensional CT may be useful for diagnosis, choice of management, and elucidating etiology of sigmoid volvulus in the elderly.
Neutrophil elastase in pressure ulcer fluid degrades fibronectin in the exudates
Authors: Ai Shingo , Kuzuya Masafumi , Iguchi Akihisa
Published: August 2004

Background:  Pressure ulcers are classified as chronic wounds, which do not heal in a timely fashion. Fibronectin is condensed in granulation tissue, and essential glycoprotein of wound healing. It has been proposed that fibronectin degradation may be involved in delaying wound healing. We have investigated whether pressure ulcer fluid (PUF) contains degraded fibronectin. In addition, we tried to identify the proteinase which contributes to fibronectin degradation in PUF.

Methods:  Fibronectin degradation and the presence of neutrophil elastase (NE) in PUF were determined by immunoblot analysis. Fibronectin degradation activity in PUF was determined in the presence of various proteinase inhibitors. NE activity was assessed using NE specific substrate.

Results:  Immunoblot analysis revealed that degraded fibronectin was observed in PUF samples but not in acute wound fluid (AWF). The PUF contained a proteinase capable of degrading freshly added fibronectin and its activity in PUF was blocked by a broad‐spectrum serine proteinase inhibitor or sivelestat, a specific neutrophil elastase inhibitor, but not by metalloproteinase and cysteine proteinase inhibitors. Immunoblot analysis of PUF using an antineutrophil elastase antibody revealed that neutrophil elastase was detected as three bands at molecular weights of ∼30 kDa, ∼38 kDa, and ∼54 kDa, indicating that neutrophil elastase in the exudates existed not only as free monomers, but also in polymers or complexes with other molecules.

Conclusion:  These results suggest that PUF contains a high level of neutrophil elastase which may be involved in the delay of the healing of pressure ulcer through the fibronectin degradation.
Randomized controlled trial of glove perforation in single‐ and double‐gloving in episiotomy repair after vaginal delivery
Authors: Punyatanasakchai Piyaphan , Chittacharoen Apichart , Ayudhya Nathpong Israngura Na
Published: August 2004

Objective:  The aims of the study presented here were to compare the rate of glove perforation between single‐gloving and double‐gloving methods, and the time of operation and level of surgeon in episiotomy repair after vaginal delivery.

Method:  A prospective randomized controlled trial was performed from the beginning of May to the end of December, 2002 at Ramathibodi Hospital. A comparison of glove perforation between single‐gloving and double‐gloving methods was performed. Glove perforations were tested by filling each glove with water. Glove perforation rate, position of perforation, time of operation and surgeon level of experience were analyzed.

Results:  One hundred and fifty sets of double‐gloving method and 150 sets of single‐gloving method were evaluated. The glove perforation rates were 4.6 and 18% in double‐inner gloves and single‐gloves, respectively, with statistical difference (P < 0.05). There was no significant difference between glove perforation rates in double‐outer gloves (22.6%) and single‐gloves (18%). There was matched perforation of the same finger of both outer and inner gloves in 2% of all double‐inner gloves. The frequency of glove perforation was classified by the surgeon's level of experience and time of operation was no difference in each level.

Conclusion:  The double‐gloving method significantly reduced the risk of exposure of the surgeon's hand to the patient's blood, when compared with the single‐gloving method in episiotomy repair. There were no differences in the rate of glove perforations compared to the time of operation and level of surgeon.
Neutrophil apoptosis in preeclampsia, do steroids confound the relationship?
Authors: Fuchisawa Akiko , Van Eeden Stephan , Magee Laura A. , Whalen Beth , Leung Peter C. K. , Russell James A. , Walley Keith R. , Von Dadelszen Peter
Published: August 2004

Aim:  To investigate the influence of maternal corticosteroid administration on neutrophil apoptosis in early onset preeclampsia.

Methods:  We investigated five groups: early onset preeclampsia (EOPET, <34 weeks, n = 10); late‐onset preeclampsia (LOPET, ≥34 weeks, n = 7); normotensive intrauterine growth restriction (nIUGR, n = 11); normal pregnancy (NPC, n = 22); and non‐pregnancy (n = 10). We examined, by flow cytometry, spontaneous neutrophil apoptosis after 18 h culture (hypodiploid DNA, Annexin V binding, propidium iodide [PI] permeability).

Results:  For the 10 women with EOPET exposed to betamethasone in the previous 48 h, we found that neutrophil apoptosis was not inappropriately inhibited, in contrast to our previous findings in women not thus exposed. Neither LOPET nor nIUGR differed from normal pregnancy.

Conclusion:  Betamethasone alters the rate of spontaneous neutrophil apoptosis in EOPET. The anti‐inflammatory influence of betamethasone may explain some of the differences between our previous and present findings with respect to neutrophil apoptosis in EOPET. Corticosteroids ameliorate the course of antenatal and postnatal preeclampsia. These results may reflect the mechanisms that underlie the transient improvements seen with antenatal dexamethasone use.
Unusual form of superficial spreading microinvasive squamous cell carcinoma of uterine cervix involving the endometrium of uterus
Authors: Tan Geok Chin , Isa Mohamed Rose , Ng Soon Pheng , Jamil Yassin Muhd Abd
Published: August 2004

Microinvasive squamous cell carcinoma of the uterine cervix is a recognized entity and is defined as carcinoma with invasion of less than 5 mm penetration of the stroma and seldom metastasized. Our patient was a 70‐year‐old, multiparous woman who had a microinvasive, cervical, squamous cell carcinoma. The tumor had spread superficially into the entire endometrial cavity up to the fundus, totally replacing the columnar epithelium. This is an extremely rare phenomenon, with fewer than 20 cases reported so far in the literature.
The Relation between Real Wage Rates and Employment: An Intertemporal General- Equilibrium Analysis
Authors: Hellwig Martin
Published: August 2004

The paper studies the relation between real wage rates and employment in an intertemporal model in which expectations of subsequent real wage rates affect equilibrium capital investments and equilibrium interest rates in previous periods. Whether the wage-employment tradeoff is more favourable or less favourable in this model than in the static model with given capital depends on whether there is relatively more substitution in consumption or in production, or, more precisely, whether the elasticity of substitution in production is less than or greater than the inverse of the elasticity of marginal utility in consumption.
HIV and AIDS among fisherfolk: a threat to ‘responsible fisheries'?
Authors: Allison Edward H. , Seeley Janet A.
Published: August 2004

Fishing communities are often among the highest‐risk groups in countries with high overall rates of HIV/AIDS prevalence. Vulnerability to HIV/AIDS stems from complex, interacting causes that may include the mobility of many fisherfolk, the time fishermen spend away from home, their access to daily cash income in an overall context of poverty and vulnerability, their demographic profile, the ready availability of commercial sex in fishing ports and the subcultures of risk taking and hypermasculinity among some fishermen. The subordinate economic and social position of women in many fishing communities in low‐income countries makes them even more vulnerable. HIV/AIDS in fishing communities was first dealt with as a public health issue, and most projects were conducted by health sector agencies and NGOs, focusing on education and health care provision. More recently, as the social and economic impacts of the epidemic have become evident, wider social service provision and economic support have been added. In the last 3 years, many major fishery development programmes in Africa, South/South‐East Asia and the Asia‐Pacific region have incorporated HIV/AIDS awareness in their planning. The HIV/AIDS pandemic threatens the sustainability of fisheries by eclipsing the futures of many fisherfolk. The burden of illness puts additional stresses on households, preventing them from accumulating assets derived from fishing income. Premature death robs fishing communities of the knowledge gained by experience and reduces incentives for longer‐term and inter‐generational stewardship of resources. Recent projects championing local knowledge and resource‐user participation in management need to take these realities into account. If the fishing communities of developing countries that account for 95% of the world's fisherfolk and supply more than half the world's fish are adversely impacted by HIV/AIDS, then the global supply of fish, particularly to lower‐income consumers, may be jeopardized.
Political Science as a Broad Church: The Search for a Pluralist Discipline
Authors: Marsh David , Savigny Heather
Published: August 2004

In 1996 Robert Goodin and Hans-Dieter Klingemann published an edited collection of essays, A New Handbook of Political Science, that provides probably the best overview of the discipline of political science, at least as seen through the eyes of the mainstream of the profession. Goodin is an American working at the Australian National University, while Klingemann is a German working in Berlin. Nevertheless, their overview represents an American view of political science, which is hardly surprising as more than 75 per cent of living political scientists are American. Overall, they present a picture of the discipline as professional, pluralistic and improving rapidly. Here, we take issue with that view, not as an ambition, but as a reality. In contrast, we argue that political science, particularly US political science, is still dominated by a positivist epistemology and, particularly, by behaviouralist and rational choice approaches that are underpinned by that positivism. We begin by outlining Goodin and Klingemann's argument and critiquing it. Subsequently, we take issue with them empirically, using evidence drawn both from their own edited collection and an analysis of the contents of the two foremost US and UK journals; in the US the American Political Science Review, the American Political Science Association's main journal, and the American Journal of Political Science, and in the UK the British Journal of Political Science and Political Studies, the Political Studies Association's main journal. The methodology adopted is discussed below. In the last section, we consider the consequence of our findings for the future of political science in Britain.
Self-Defence, Defence and Pre-Emption
Authors: Calhoun Laurie
Published: August 2004

Military supporters and critics often find each others' positions on war preposterous. The divergent attitudes of these two groups may derive from their view about the analogy, or lack thereof, between war and self-defence, an issue recently highlighted by the controversial question of ‘pre-emption’. In general, bombing campaigns conducted abroad are better understood as pre-emptive acts of war than as literal acts of ‘self-defence’. The support by governments of the weapons export trade is also difficult to reconcile with the ‘self-defence’ interpretation of war. Accordingly, those who reject ‘pre-emptive defence’ on the grounds that it exceeds the parameters of ‘self-defence’ should, in consistency, oppose bombing campaigns and the exportation of weapons as well.
Liberal Multiculturalism Reconsidered
Authors: Knight Carl
Published: August 2004

This article starts by setting out the evaluative criteria provided by Will Kymlicka's liberal account of individual freedom and equality. Kymlicka's theory of cultural minority rights is then analysed using these criteria and found to be defective in two respects. First, his assignment of different rights to national and ethnic groups is shown to be inegalitarian with regard to generations after the first. Second, his recommendation of strong cultural protections is shown in some circumstances to undermine freedom and equality. Towards the end of the article a policy of gradual and inclusive assimilation is described that may effectively promote the freedom and opportunities of members of cultural minorities. In conclusion, group-specific rights may, as Kymlicka says, be justified in liberal terms, but only where they differ in content from those he proposes.
Democratisation and Inter-State War: Why Reform does not Encourage Conflict
Authors: Galbreath David J.
Published: August 2004

The ‘democratic peace theory’ argues that democratic states do not initiate war against one another and that democratic institutions discourage that initiation of international conflict. In general, this theory has mostly been applied to existing liberal democracies. However, the peaceful nature of the process of democratisation is far less evident. Some scholars argue that the instability of democratic transitions increases the likelihood that democratising states will initiate international conflict, making the democratic peace theory less valuable in its explanatory power. This article, however, argues that democratising states, as opposed to authoritarian states exhibiting a brief period of liberalisation, are inherently less prone to periods of international conflict.
The Intention Debate in German Criminal Law
Authors: Taylor Greg
Published: August 2004

Abstract.  This article considers the various suggestions that have been put forward by German scholars to replace the traditional concept of intention, which the author has criticised elsewhere (Taylor 2004). The debate on this topic has become a minor academic industry in Germany, and should be better known as the English‐speaking world struggles with its own concepts of intention. Despite the great amount of effort and ingenuity devoted to this topic in Germany, however, the author concludes that only one theory of intention, that put forward by Professor Wolfgang Frisch, shows any substantial degree of promise.
Receptor targeting and heterogeneity at interneuronal nicotinic cholinergic synapses in vivo
Authors: Temburni Murali Krishna , Blitzblau Rachel C. , Jacob Michele H.
Published: August 2004

Within a single neuron the correct targeting of the diverse neurotransmitter receptor types to discrete synaptic regions is crucial for proper function. However, the molecular mechanisms that underlie neuronal receptor clustering and targeting are still largely undefined. Here we report advances in defining the mechanisms that mediate nicotinic acetylcholine receptor (nAChR) targeting to interneuronal synapses. Recent in vivo studies have demonstrated that one subunit plays a critical role in the differentiation of nicotinic cholinergic synapses on vertebrate autonomic neurons. The major cytoplasmic loop of the α3 subunit targets specific nAChR subtypes to the synapse. In contrast, nAChR complexes that lack the α3 targeting domain are excluded and are perisynaptic. Additional studies have demonstrated a greater complexity to α3‐nAChR targeting due to a unique postsynaptic receptor microheterogeneity – under one presynaptic terminal, α3‐nAChR clusters are separate, but proximal to, glycine receptor (GlyR) clusters in discrete postsynaptic membrane microregions. The surprising coexistence under one nerve ending of separate clusters of receptors that respond to different fast‐acting transmitters with opposing functions may represent a novel mechanism for modulating synaptic activity. Overall, the receptor targeting and clustering studies reviewed in this issue suggest that a common mechanism underlies the formation of the diverse types of interneuronal synapses but differs from that responsible for neuromuscular junction assembly in vertebrates.
The role of the delayed rectifier component IKs in dog ventricular muscle and Purkinje fibre repolarization
Authors: Varró András , Baláti Beáta , Iost Norbert , Takács János , Virág László , Lathrop David A. , Csaba Lengyel , Tálosi László , Papp Julius Gy.
Published: August 2004

The relative contributions of the rapid and slow components of the delayed rectifier potassium current (IKr and IKs, respectively) to dog cardiac action potential configuration were compared in ventricular myocytes and in multicellular right ventricular papillary muscle and Purkinje fibre preparations. Whole‐cell patch‐clamp techniques, conventional microelectrode and in vivo ECG measurements were made at 37°C.

Action potential duration (APD) was minimally increased (less than 7%) by chromanol 293B (10 μM) and L‐735,821 (100 nM), selective blockers of IKs, over a range of pacing cycle lengths (300–5000 ms) in both dog right ventricular papillary muscles and Purkinje fibre strands. D‐Sotalol (30 μM) and E‐4031 (1 μM), selective blockers of IKr, in the same preparations markedly (20–80%) lengthened APD in a reverse frequency‐dependent manner.

In vivo ECG recordings in intact anaesthetized dogs indicated no significant chromanol 293B (1 mg kg−1 i.v.) effect on the QTc interval (332.9 ± 16.1 ms before versus 330.5 ± 11.2 ms, n= 6, after chromanol 293B), while D‐sotalol (1 mg kg−1 i.v.) significantly increased the QTc interval (323.9 ± 7.3 ms before versus 346.5 ± 6.4 ms, n= 5, after D‐sotalol, P < 0.05).

The current density estimated during the normal ventricular muscle action potential (i.e. after a 200 ms square pulse to +30 mV or during a 250 ms long ‘action potential‐like’ test pulse) indicates that substantially more current is conducted through IKr channels than through IKs channels. However, if the duration of the square test pulse or the ‘action potential‐like’ test pulse was lengthened to 500 ms the relative contribution of IKs significantly increased.

When APD was pharmacologically prolonged in papillary muscle (1 μM E‐4031 and 1 μg ml−1 veratrine), 100 nM L‐735,821 and 10 μM chromanol 293B lengthened repolarization substantially by 14.4 ± 3.4 and 18.0 ± 3.4% (n= 8), respectively.

We conclude that in this study IKs plays little role in normal dog ventricular muscle and Purkinje fibre action potential repolarization and that IKr is the major source of outward current responsible for initiation of final action potential repolarization. Thus, when APD is abnormally increased, the role of IKs in final repolarization increases to provide an important safety mechanism that reduces arrhythmia risk.
Chronic passive cigarette smoke exposure augments bronchopulmonary C‐fibre inputs to nucleus tractus solitarii neurones and reflex output in young guinea‐pigs
Authors: Mutoh T. , Joad J. P. , Bonham A. C.
Published: August 2004

Children chronically exposed to environmental tobacco smoke (passive cigarette smoke) have more wheeze, cough, bronchoconstriction, airway hyper‐reactivity and mucous secretion, which may result, in part, from stimulation of the vagal bronchopulmonary C‐fibre reflex.

Environmental tobacco smoke increases the sensitivity of bronchopulmonary C‐fibre endings, but the physiological relevance of this sensitization is unknown. If this exposure augments the reflex responses via a central mechanism, then the responses of higher‐order neurones in the reflex pathway and some components of the reflex output should also be augmented.

Guinea‐pigs were chronically exposed to sidestream tobacco smoke (surrogate for environmental tobacco smoke) or filtered air for 5 days week−1 from age 1 to 6 weeks (age equivalent of human childhood) and were then anaesthetized, paralysed, ventilated and prepared with pneumothoraces. Baseline and left atrial capsaicin (0.5 and 2.0 μg kg−1)‐ evoked changes in the impulse activity of vagal C‐fibre‐activated neurones in nucleus tractus solitarii (NTS), phrenic nerve activity, tracheal pressure, arterial blood pressure and heart rate were compared in the two groups.

Sidestream smoke exposure significantly augmented the peak (P= 0.02) and duration (P= 0.01) of the NTS neuronal responses and the prolongation of expiratory time (P= 0.003) at the higher capsaicin dose.

Thus, the sensitization of the bronchopulmonary C‐fibre endings by chronic exposure to sidestream tobacco smoke is transmitted to the NTS and is associated with a prolonged reflexively evoked expiratory apnoea. The findings may help to explain some related respiratory symptoms in children and be a factor in sudden infant death syndrome.
Mechanically gated channel activity in cytoskeleton‐deficient plasma membrane blebs and vesicles from Xenopus oocytes
Authors: Zhang Yong , Gao Feng , Popov Vsevolod L. , Wen Julie W. , Hamill Owen P.
Published: August 2004

A novel technique involving hypertonic stress causes membrane ‘blebbing’ of the Xenopus oocyte and the shedding of plasma membrane vesicles (PMVs).

Confocal fluorescence microscopy, immunocytochemistry and electron microscopy indicate that blebs and PMVs lack cortical cytoskeleton and are deficient in cytoskeleton proteins and devoid of microvilli.

Patch recordings from PMVs consistently reveal mechanically gated (MG) channel activity. The MG channels display the same single‐channel conductance as control recordings but differ in terms of reduced mechanosensitivity and adaptation to sustained stimulation.

Whole PMV recordings show rapid and reversible activation of mechanosensitive currents in response to pressure pulses. The maximal currents activated in PMVs are consistent with MG channel activity recorded in patches.

The discrepancy between MG channel activity recorded in whole PMVs and oocytes most probably reflects their different membrane geometry and ability to develop activating bilayer tensions.

We propose that membrane blebbing, which is known to occur under specific physiological and pathological conditions (e.g. mitosis and apoptosis), may increase mechanosensitivity independently of the intrinsic properties of membrane proteins.
Ca2+ influx via the L‐type Ca2+ channel during tail current and above current reversal potential in ferret ventricular myocytes
Authors: Zhou Zhuan , Bers Donald M.
Published: August 2004

Current through L‐type Ca2+ channels (ICa) was measured electrophysiologically at the same time as Ca2+ influx was measured by trapping entering Ca2+ with a high concentration of indo‐1 (> 1 mm) in ferret ventricular myocytes.

Na+‐free conditions prevented Na+‐Ca2+ exchange and K+ currents were blocked by Cs+ and TEA. Thapsigargin (5 μM) prevented Ca2+ uptake and release by the sarcoplasmic reticulum. ICa was pre‐activated by brief pulses to +120 mV (the equilibrium potential for Ca2+, ECa), followed by steps to different membrane potentials (Em, −80 to +100 mV), in some cases in the presence of the Ca2+ channel agonist FPL‐64176.

Integrated ICa (ICa) was linearly related to the change in the concentration of Ca2+ bound to indo‐1, which was assessed by the fluorescence difference signal ΔFd (Fd=F500–F400). This created an internal calibration of ΔFd as a measure of Ca2+ influx.

The ΔFd/ICadt relationship was virtually unchanged at all measurable inward ICa (at Em from −80 to +50 mV). This indicates that the fractional current carried by Ca2+ and channel selectivity are unchanged over this Em range, and also that the selectivity for Ca2+ is very high.

Ca2+ influx was readily detected by ΔFd beyond the ICa reversal potential (+65 to +100 mV) and was not abolished until Em was +120 mV (i.e. ECa). This is explained by the fact that inward Ca2+ flux at the ICa reversal potential is exactly balanced by outward Cs+ current through the Ca2+ channels and can be described by classic Goldman flux analysis with a Ca2+/Cs+ selectivity of the order of 5000.

This result also emphasizes that net Ca2+ influx via Ca2+ channels occurs over a voltage range where the net channel current is outward.
Muscarinic receptor‐induced acidification in sublingual mucous acinar cells: loss of pH recovery in Na+−H+ exchanger‐1 deficient mice
Authors: Nguyen Ha‐Van , Shull Gary E. , Melvin James E.
Published: August 2004

Intracellular pH (pHi) plays an important role in regulating fluid and electrolyte secretion by salivary gland acinar cells. The pH‐sensitive, fluorescent dye 2′,7′‐bis(carboxyethyl)−5(6)‐carboxylfluorescein (BCECF) was used to characterize the mechanisms involved in regulating pHi during muscarinic stimulation in mouse sublingual mucous acinar cells.

In the presence of HCO3−, muscarinic stimulation caused a rapid decrease in pHi (0.24 ± 0.02 pH units) followed by a slow recovery rate (0.042 ± 0.002 pH units min−1) to the initial resting pHi in sublingual acinar cells. The muscarinic receptor‐induced acidification in parotid acinar cells was of a similar magnitude (0.25 ± 0.02 pH units), but in contrast, the recovery rate was ≈4‐fold faster (0.181 ± 0.005 pH units min−1).

The agonist‐induced intracellular acidification was inhibited by the anion channel blocker niflumate, and was prevented in the absence of HCO3− by treatment with the carbonic anhydrase inhibitor methazolamide. These results indicate that the muscarinic‐induced acidification is due to HCO3− loss, probably mediated by an anion conductive pathway.

The Na+−H+ exchange inhibitor 5‐(N‐ethyl‐N‐isopropyl)amiloride (EIPA) amplified the magnitude of the agonist‐induced acidification and completely blocked the Na+‐dependent pHi recovery.

To examine the molecular nature of the Na+−H+ exchange mechanism in sublingual acinar cells, pH regulation was investigated in mice lacking Na+−H+ exchanger isoforms 1 and 2 (NHE1 and NHE2, respectively). The magnitude and the rate of pHi recovery in response to an acid load in acinar cells isolated from mice lacking NHE2 were comparable to that observed in cells from wild‐type animals. In contrast, targeted disruption of the Nhe1 gene completely abolished pHi recovery from an acid load. These results demonstrate that NHE1 is critical for regulating pHi during a muscarinic agonist‐stimulated acid challenge and probably plays an important role in regulating fluid secretion in the sublingual exocrine gland.

In NHE1‐deficient mice, sublingual acinar cells failed to recover from an acid load in the presence of bicarbonate. These results confirm that the major regulatory mechanism involved in pHi recovery from an acid load is not Na+−HCO3− cotransport, but amiloride‐sensitive Na+−H+ exchange via isoform 1.
Inhibition of KCNQ1‐4 potassium channels expressed in mammalian cells via M1 muscarinic acetylcholine receptors
Authors: Selyanko A. A. , Hadley J. K. , Wood I. C. , Abogadie F. C. , Jentsch T. J. , Brown D. A.
Published: August 2004

KCNQ1‐4 potassium channels were expressed in mammalian Chinese hamster ovary (CHO) cells stably transfected with M1 muscarinic acetylcholine receptors and currents were recorded using the whole‐cell perforated patch technique and cell‐attached patch recording.

Stimulation of M1 receptors by 10 μm oxotremorine‐M (Oxo‐M) strongly reduced (to 0–10%) currents produced by KCNQ1‐4 subunits expressed individually and also those produced by KCNQ2+KCNQ3 and KCNQ1+KCNE1 heteromers, which are thought to generate neuronal M‐currents (IK,M) and cardiac slow delayed rectifier currents (IK,s), respectively.

The activity of KCNQ2+KCNQ3, KCNQ2 and KCNQ3 channels recorded with cell‐attached pipettes was strongly and reversibly reduced by Oxo‐M applied to the extra‐patch membrane.

It is concluded that M1 receptors couple to all known KCNQ subunits and that inhibition of KCNQ2+KCNQ3 channels, like that of native M‐channels, requires a diffusible second messenger.
Signalling pathway for histamine activation of non‐selective cation channels in equine tracheal myocytes
Authors: Wang Yong‐Xiao , Kotlikoff Michael I.
Published: August 2004

The signalling pathway underlying histamine activation of non‐selective cation channels was investigated in single equine tracheal myocytes. Application of histamine (100 μM) activated the transient calcium‐activated chloride current (ICl(Ca)) and sustained, low amplitude non‐selective cation current (ICat). The H1 receptor antagonist pyrilamine (10 μM) blocked activation of ICl(Ca) and ICat. Simultaneous application of histamine (100 μM) and caffeine (8 mm) during H1 receptor blockade activated ICl(Ca), but not ICat. Neither the H2 receptor antagonist cimetidine (20 μM) nor the H3 receptor antagonist thioperamide (20 μM) prevented activation of ICl(Ca) and ICat.

Intracellular dialysis of anti‐Gαi/Gαo antibodies completely blocked activation of ICat by histamine, whereas ICl(Ca) was not affected. By contrast, anti‐Gαq/Gα11 antibodies greatly inhibited ICl(Ca), but did not alter activation of ICat.

1‐Oleoyl‐2‐acetyl‐sn‐glycerol (OAG, 20–100 μM) did not induce any current or affect currents activated by histamine or methacholine (mACH). Simultaneous application of OAG and caffeine activated ICl(Ca), but not ICat, indicating that a rise in [Ca2+]i and stimulation of diacylglycerol‐sensitive protein kinase C (PKC) is not sufficient to activate ICat. The phospholipase C inhibitor U73122 (2 μM) blocked histamine activation of ICl(Ca) and ICat, but simultaneous exposure of myocytes to histamine and caffeine restored both ICl(Ca) and ICat in the presence of U73122.

Histamine and mACH activated currents with equivalent I–V relationships. The currents activated by these agonists were not additive; following activation of ICat by mACH, histamine failed to induce an additional membrane current. Similarly, mACH did not induce an additional current after full activation of ICat by histamine.

We conclude that H1 histamine receptors activate ICat through coupling to Gi/Go proteins. Activation of ICat also requires intracellular calcium release, mediated by H1 receptors coupling to Gq/G11 proteins. This coupling is analogous to the activation of ICat by co‐stimulation of M2 and M3 receptors.
Ventilatory and central neurochemical reorganisation of O2 chemoreflex after carotid sinus nerve transection in rat
Authors: Roux J. C. , Peyronnet J. , Pascual O. , Dalmaz Y. , Pequignot J. M
Published: August 2004

The first step of this study was to determine the early time course and pattern of hypoxic ventilatory response (HVR) recovery following irreversible bilateral carotid sinus nerve transection (CSNT). The second step was to find out if HVR recovery was associated with changes in the neurochemical activity of the medullary catecholaminergic cell groups involved in the O2 chemoreflex pathway.

The breathing response to acute hypoxia (10% O2) was measured in awake rats 2, 6, 10, 45 and 90 days after CSNT. In a control group of sham‐operated rats, the ventilatory response to hypoxia was principally due to increased respiratory frequency. There was a large reduction in HVR in the CSNT compared to the sham‐operated rats (−65%, 2 days after surgery). Within the weeks following denervation, the CSNT rats progressively recovered a HVR level similar to the sham‐operated rats (‐37% at 6 days, −27% at 10 days, and no difference at 45 or 90 days). After recovery, the CSNT rats exhibited a higher tidal volume (+38%) than the sham‐operated rats in response to hypoxia, but not a complete recovery of respiratory frequency.

Fifteen days after CSNT, in vivo tyrosine hydroxylase (TH) activity had decreased in caudal A2C2 (−35%) and A6 cells (−35%). After 90 days, the CSNT rats displayed higher TH activity than the sham‐operated animals in caudal A1C1 (+51%), caudal A2C2 (+129%), A5 (+216%) and A6 cells (+79%).

It is concluded that HVR following CSNT is associated with a profound functional reorganisation of the central O2 chemoreflex pathway, including changes in ventilatory pattern and medullary catecholaminergic activity.
PCR primers for fish G6PD gene intron and characterization of intron length variation in the albacore Thunnus alalunga
Authors: CHOW S. , NAKADATE M.
Published: August 2004

Polymerase chain reaction (PCR) primers to amplify the fourth intron of glucose‐6‐phosphate dehydrogenase (G6PD) gene were designed. A large length variation of amplified fragment was observed in the Atlantic albacore sample with a moderate level of heterozygosity (HE = 0.488). Nucleotide sequence analysis revealed deletion or insertion of a large nucleotide block (110 base pairs) to be responsible for the length difference. Successful amplification of single or two fragments was confirmed in the northern bluefin tuna and Pacific saury, indicating the wide cross‐species applicability.
Isolation and characterization of microsatellites inDrosophila montanaand their cross‐species amplification inD. virilis
Authors: ORSINI L. , SCHLÖTTERER C.
Published: August 2004

We report the isolation of 20 microsatellite loci fromDrosophila montanaand their cross amplification in the relativeD. virilis. All microsatellite loci were polymorphic in the focal speciesD. montana, with gene diversities ranging from 0.23 to 0.93. InD. virilisonly eight loci (40%) amplified and two loci were polymorphic (10%). These markers represent the first report of microsatellites isolated inD. montana. They could be applied for studying population structure and phylogeography. The largest benefit, however, will be their use in studies of quantitative trait loci, such as the mapping of behavioural quantitative trait loci.
Development of polymorphic microsatellite markers for the Steere's Liocichla (Liocichla steerii)
Authors: YEUNG CAROL , HUANG YI‐JIUN , LI SHOU‐HSIEN
Published: August 2004

For the Steere's Liocichla (Liocichla steerii) we developed seven polymorphic microsatellite markers from a partial genomic library enriched for GATA, tetranucleotide repeats. Among the 27–28 individuals screened, allelic diversity ranged from six to 19 alleles per locus and the observed heterozygosity of each locus ranged from 0.250 to 0.889. All loci conformed to Hardy–Weinberg expectations except for two that appeared to be Z‐Iinked; such Z‐Iinked loci can be used in studies of male dispersal.
Characterization of eight polymorphic microsatellites in the shrew Crocidura suaveolens and its application to the study of insular populations of the French Atlantic coast
Authors: CALMET CLAIR. E. , LAMBOURDIÈRE JOSIE , ABDELKRIM JAWAD , PASCAL MICHEL , SAMADI SARAH
Published: August 2004

We developed eight polymorphic microsatellite loci to study the natural populations of Crocidura suaveolens, the lesser white‐toothed shrew. These loci are used in the study of insular populations of the French Atlantic coast where these shrews exhibit gigantism features that suggest an insular syndrome. These populations were threatened by the invasion of the rat Rattus norvegicus and the eradication of this alien pest in some islands was followed by a demographic expansion of the shrew populations. These first genetic results suggest that the shrew populations in the three studied islands are very differentiated.