bluuebunny/crossref_metadata_2025_split huggingface dataset:
Egg cannibalism byColeomegilla maculata lengineonates: preference even in the presence of essential prey
Authors: Gagné Isabelle , Coderre Daniel , Mauffette Yves 
Published: March 2003

Abstract1. Egg cannibalism among coccinellids has been reported widely, however reasons why this type of behaviour is observed so frequently have been neglected. This experiment was undertaken to clarify whether cannibalistic behaviour is advantageous toColeomegilla maculata lengiThimberlake neonates and to understand the reasons for high levels of egg cannibalism.2. Benefits gained by neonate cannibals were ascertained by comparing survival, developmental time, and second‐instar weight ofC. maculatalarvae that were allowed to cannibalise conspecific eggs or not. Preference and behaviour tests were also conducted to assess the reasons for high levels of egg cannibalism.3. Cannibal neonates grew faster and were heavier than non‐cannibals. The developmental time of neonates was influenced more by prey vulnerability than by prey quality.4. In choice tests, where three different proportions of conspecific eggs and aphids were offered (33–67, 50–50, and 67–33%),C. maculataneonates always consumed significantly more eggs. Manly's preference indexes indicated that neonates showed a consistent preference for conspecific eggs.5. Seventy‐five per cent of neonates observed went directly towards eggs and 90% of the first prey consumed by neonates were an egg. When aphids were painted with extract of crushed eggs and eggs with crushed aphids to determine whether neonates found eggs by chemical cues, neonates preferred aphids painted with egg extract to eggs painted with aphid extract.6. It was concluded thatC. maculataneonates benefited from cannibalistic behaviour. Moreover, egg cannibalism is not related only to frequency of encounter; chemical cues are also involved in egg searching.
Flexible use of patch marks in an insect predator: effect of sex, hunger state, and patch quality
Authors: Nakashima Yoshitaka , Teshiba Mayumi , Hirose Yoshimi 
Published: March 2003

Abstract 1. Patch marks that allow the subsequent avoidance of marked areas may be used by small animals to increase foraging efficiency. This study is the first to demonstrate the presence of a patch‐marking system in insect predators. Furthermore, the marking system is found only in females, and factors such as hunger state and patch quality play a key role in determining whether a female will re‐investigate a self‐marked patch.2. Females of the insect predator Orius sauteri avoided areas where the female itself had searched previously but did not avoid areas searched by conspecific females when deprived of prey for 24 h. There was no evidence that males use such a patch‐marking system, indicating the presence of a sex difference in patch‐mark use.3. Females did not discriminate between patches visited previously and patches not visited when they were either well fed or when patches contained abundant prey.4. The patch mark used by females was effective for ≤ 1 h and may be a reliable indicator of a recently visited area in which prey have been depleted.5. These results suggest that O. sauteri females have the flexibility to adjust their behavioural responses to a previously searched area depending on their hunger state and the availability of prey in their foraging environment.
Desiccation of Pinus foliage induced by conifer sawfly oviposition: effect on egg viability
Authors: Codella Sylvio G. , Raffa Kenneth F. 
Published: March 2003

Abstract 1. Desiccation of needles following oviposition by Neodiprion lecontei in Pinus resinosa caused high egg mortality. Eight‐five per cent of pine needles into which sawflies oviposited subsequently desiccated, compared with 2.5% of needles without eggs. No larval emergence occurred from desiccated needles.2. Within affected shoots, the probability of desiccation increased with the extent of oviposition. In paired comparisons of needles, 41.2% of needle length was occupied by eggs in desiccated needles, compared with 24.0% of needles without desiccation.3. Both density‐dependent and density‐independent factors may contribute to desiccation of egg‐laden needles. The likelihood that needle vasculature will be severed by ovipositing females probably increases with population density. Drought, which was high during the observations, probably increases the incidence of needle desiccation following mechanical injury caused by oviposition.
Life‐cycle variation in the aphid Sitobion avenae: costs and benefits of male production
Authors: Helden Alvin J. , Dixon A. F. G. 
Published: March 2003

Abstract 1. Patterns of male production and life‐cycle variation were investigated in the aphid Sitobion avenae. Seventy‐seven field‐collected clones were subjected to a 14 °C short day‐length regime to assess their reproductive modes, and three clones were used to study life‐cycle inheritance. A further analysis assessed the cost of male production.2. In comparison with those from East Anglia, there were more holocyclic and intermediate clones found in Scottish populations, and they produced significantly more mating females. In total, 44% of clones were androcyclic.3. The inheritance of life cycle showed a greater level of complexity than could be achieved by previously suggested monohybrid inheritance mechanisms.4. Holocyclic and intermediate clones produced a higher proportion of males than did androcyclic clones. Inter‐clonal differences were reflected in the pattern of male production in the reproductive sequence.5. A significant cost was associated with male production in terms of a reduction in both fecundity and total offspring biomass.6. Winged females rarely gave birth to males but the pattern of mating female production differed between holocyclic and intermediate clones.7. Patterns of male and mating female production by the different types of clone may be related to different advantages and disadvantages of dispersal and inbreeding.8. Recent models of aphid overwintering could be enhanced by consideration of issues raised in this study, such as the cost of male production, the inheritance of life cycle, and the patterns of sexual morph production.
Oviposition patterns in a predatory mite reduce the risk of egg predation caused by prey
Authors: Faraji Farid , Janssen Arne , Sabelis Maurice W. 
Published: March 2003

Abstract 1. Predatory arthropods lay their eggs such that their offspring have sufficient prey at their disposal and run a low risk of being eaten by conspecific and heterospecific predators, but what happens if the prey attacks eggs of the predator?2. The egg distribution and time allocation of adult female predatory mites Iphiseius degenerans as affected by predation of their eggs by prey, the western flower thrips Frankliniella occidentalis, were studied on sweet pepper plants. The predatory mites attack the first instar of thrips but all active stages of thrips are capable of killing the eggs of the predator; however the predatory mite is used for biological control of thrips.3. The majority of predatory mite eggs was laid on the underside of leaves in hair tufts (domatia). During the experiment, females spent increasing amounts of time in flowers where they fed on pollen and thrips larvae. The risk of predation on predator eggs by thrips was lower on leaves than in flowers where the majority of thrips resides. Moreover, predation risk was higher outside leaf domatia than inside.4. This suggests that predators avoid ovipositing in places with abundant prey to prevent their eggs from being eaten by thrips.
Seasonal sex ratio and unbalanced investment sex ratio in the Banksia bee Hylaeus alcyoneus
Authors: Paini Dean R. , Bailey Winston J. 
Published: March 2003

Abstract 1. Hylaeus alcyoneus is an endemic solitary bee common on coastal heaths of Western Australia. The bee is unusual in that males are larger than females. This size dimorphism presents an opportunity to test the theory of resource‐dependent sex allocation, in which theory predicts that when resources are low the sex ratio should be biased towards the smaller sex. In most bees, females are larger than males and, in line with theoretical prediction, sex ratios are male biased when resources are scarce.2. The emerging sex ratio and brood mass from a natural population of H. alcyoneus using trap nests was studied over two seasons (1999, 2000). A switch from a male‐ to a female‐biased sex ratio through the season was found, which was related to a reduced floral resource.3. Fisherian sex ratio theory predicts that total investment in each sex throughout a season should be equal and that the sex ratio should be biased towards the smaller sex. By measuring the mass of the emerging progeny, the total investment was found to favour males. Possible explanations for this bias in investment are discussed.
Gastroduodenal permeability in Crohn's disease
Authors: Püspök  , Oberhuber  , Wyatt  , Maier‐Dobersberger  , Hammer  , Pfeffel  , Wrba  , Pötzi  , Vogelsang  
Published: March 2003

BackgroundGastric permeability was prospectively investigated by determination of sucrose excretion in 100 patients with Crohn's disease. Results were compared with histological findings and the lactulose–mannitol ratio as a measure of intestinal permeability.MethodsAll subjects underwent oesophagogastroduodenoscopy with biopsies of all investigated parts. Thirty‐two Helicobacter pylori‐positive patients were excluded from further analyses.ResultsGastroduodenal permeability was significantly higher in patients with Crohn's disease than in control subjects (P < 0.00001). Sucrose excretion alone did not predict microscopic inflammation of the upper gastrointestinal tract. Increased gastroduodenal permeability with a concomitant rise in intestinal permeability predicted histological upper gastrointestinal involvement of Crohn's disease with a likelihood of 86%. The negative predictive value was 43%.ConclusionIn parallel with findings in the small intestine, gastroduodenal permeability is increased in a high proportion of patients with Crohn's disease. In patients with an increased lactulose–mannitol ratio, elevated sucrose excretion is highly predictive of histological gastroduodenal involvement.
Release of peptide YY and inhibition of gastric acid secretion by long‐chain and medium‐chain triglycerides but not by sucrose polyester in men
Authors: Maas  , Hopman  , Katan  , Jansen  
Published: March 2003

MethodsIn the present study, we have investigated the effects of intraduodenal perfusion of long‐chain and medium‐chain triglycerides and of sucrose polyester on the release of peptide YY in healthy men.ResultsPerfusion of medium‐chain triglycerides (180 mmol fatty acids) increased the plasma concentration of peptide YY from 7.9 pmol L−1 (SEM 0.2, n = 8) to 10.7 pmol L−1 (SEM 0.5, n = 8), whereas perfusion of long‐chain triglycerides (180 mmol fatty acids) had a significantly greater effect, increasing peptide YY concentration from 8.6 pmol L−1 (SEM 0.2, n = 8) to 18.9 pmol L−1 (SEM 2.4, n = 8, P < 0.008). A smaller quantity of long‐chain triglycerides (90 mmol fatty acids) increased plasma concentration of peptide YY from 7.4 pmol L−1 (SEM 0.4, n = 8) to 13.3 pmol L−1 (SEM 1.5, n = 8), whereas sucrose polyester (90 mmol fatty acids) did not change peptide YY concentration. In a previous study, we investigated gastrin‐stimulated gastric acid output in response to these treatments. The correlation between increases in peptide YY in response to all treatments and the decrease in acid output was r = 0.72 (n = 48, P < 0.0001). These results show that both long‐chain and medium‐chain triglycerides, but not sucrose polyester, stimulate the release of peptide YY.ConclusionWe speculate that peptide YY may play an important role in the inhibition of gastrin‐stimulated gastric acid secretion by long‐chain and medium‐chain triglycerides.
Chromatographically identified alcohol‐induced haemoglobin adducts as markers of alcohol abuse among women
Authors: Hurme  , Seppä  , Rajaniemi  , Sillanaukee  
Published: March 2003

BackgroundAlcohol‐induced changes in haemoglobin have been suggested as potential biochemical markers of alcohol abuse. In this study, we investigated the diagnostic value of alcohol‐induced haemoglobin adducts among women.MethodsWhole (Hb fractions) and affinity‐purified (AHb fractions) haemolysates from 87 women in three groups — (a) social drinkers (n = 31), (b) heavy drinkers (n = 27) and (c) alcoholic subjects (n = 29) — were analysed by HPLC–CEC.ResultsThree fractions (HbA1a2, HbA1d1 and AHbA1d1) showed significant differences (P < 0.05) between the groups and a significant positive correlation (P < 0.05) with self‐reported alcohol consumption (r = 0.58–76) as determined by the Malmö modified Michigan Alcoholism Screening Test (MmMAST) and structured CAGE questionnaire (r = 0.58–0.76). HbA1a2, HbA1d1 and AHbA1d1 had specificities of 97%, 97% and 100% respectively and detected 41%, 33% and 78% of heavy drinkers with overall accuracies (OAs) of 71%, 67% and 90%. Sensitivities in the detection of alcoholic subjects were 86% (OA = 92%), 76% (OA = 87%) and 81% (OA = 91%) respectively. The fractions had higher OAs than traditional markers of alcohol abuse.ConclusionThis study indicates that at least three alcohol‐induced haemoglobin adducts occurring in vivo can be measured with promising diagnostic efficiency among women.
Effects of short‐term treatment with pravastatin on the hepatic synthesis of cholesterol and bile acids in gallstone patients
Authors: Hillebrant  , Axelson  , Björkhem  , Wang  , Nyberg  , Einarsson  
Published: March 2003

BackgroundHMG‐CoA reductase inhibitors are now the therapy of choice in the treatment of hypercholesterolaemia. The effects of long‐term treatment with these substances on plasma lipoproteins, cholesterol metabolism and biliary secretion of lipids have been extensively studied in humans. Much less is known about the effects of short‐term treatment. The aim of this study was to determine the time course of the effects of HMG‐CoA reductase inhibitors on plasma lipoprotein levels as well as cholesterol and bile acid synthesis in gallstone patients.MethodsThirty‐six patients undergoing elective cholecystectomy were included in the study. Except for the gallstone disease, these patients were otherwise healthy. Four groups of subjects were treated with the HMG‐CoA reductase inhibitor pravastatin (Pravachol), 20 mg twice daily for 12, 24, 48 and 72 h preoperatively. Plasma lipoproteins and plasma levels of lathosterol and 7α‐hydroxy‐4‐cholesten‐3‐one were determined before initiation of pravastatin treatment and on the morning of the day of the operation, lathosterol reflecting hepatic HMG‐CoA reductase activity and 7α‐hydroxy‐4‐cholesten‐3‐one the activity of cholesterol 7α‐hydroxylase, the rate‐determining enzyme in bile acid synthesis.ResultsAll treatment groups displayed a significant decrease in total cholesterol and low‐density lipoprotein (LDL)‐cholesterol, by about 12% and 17% respectively. Lathosterol was reduced by about 50% in all treatment groups. Of great interest was the finding that 7α‐hydroxy‐4‐cholesten‐3‐one was unaffected in all treatment groups.ConclusionThe results show that short‐term pravastatin treatment in gallstone patients rapidly inhibits cholesterol synthesis and lowers plasma LDL‐cholesterol levels without effects on bile acid synthesis.
Association of copper to metallothionein in hepatic lysosomes of Long–Evans cinnamon (LEC) rats during the development of hepatitis
Authors: Klein  , Lichtmannegger  , Heinzmann  , Müller‐Höcker  , Michaelsen  , Summer  
Published: March 2003

BackgroundThe Long–Evans cinnamon (LEC) rat has a mutation homologous to the human Wilson's disease gene, leading to copper‐induced hepatotoxicity. The mechanism of how excess copper damages the liver or what chemical form of copper is toxic is still unclear.ResultsIn liver cytosol, copper levels were highest just before the onset of hepatitis and declined thereafter. In cytosol, total copper was bound to metallothionein (MT). Considerable amounts of both copper and iron accumulated in lysosomes with increasing age and development of liver damage. Lysosomal levels of presumably reactive non‐MT‐bound copper were increased. In severely affected livers, large amounts of copper were associated with insoluble material of high density which, upon ultrastructural information, was found to be derived from the lysosomes of Kupffer cells. This copper‐rich material is considered to consist of polymeric degradation products of copper‐MT.ConclusionWe suggest that chronic copper toxicity in LEC rats involves the uptake of copper‐loaded MT into lysosomes, where it is incompletely degraded and polymerizes to an insoluble material containing reactive copper. This copper, together with iron, initiates lysosomal lipid peroxidation, leading to hepatocyte necrosis. Subsequent to phagocytosis by Kupffer cells, the reactive copper may amplify liver damage either directly or through stimulation of these cells.
Factors influencing the effects of murine cytomegalovirus on the pancreas
Authors: Price  , Baxter  , Allcock  , Papadimitriou  
Published: March 2003

BackgroundAs human cytomegalovirus (HCMV) infections are implicated in insulin‐dependent diabetes mellitus (IDDM), the effects of murine (M)CMV infection of inbred mice on the pancreas are of interest.ResultsInflammation and periacinar oedema peaked on day 3 and were replaced by a focal inflammation, but infected cells were rare. The islets were spared in C57BL mice. Insulitis normally seen in non‐obese diabetic (NOD) mice was accelerated, but infected NOD mice did not become glycosuric. Isotypes of total and autoreactive antibodies suggested a shift to a Th1 response (IgG2a) in all MCMV‐infected mice. MCMV‐induced pancreatitis was not affected by MHC genes but was similar or less severe in BALB/c mice. As these lack the Cmv1 gene, which provides a protective natural killer (NK) cell response in C57BL congenic mice, the C57BL background may carry a pancreatitis susceptibility gene able to counter NK‐mediated restriction of viral replication. Consistently, congenic mice expressing Cmv1 on a BALB/c background did not display pancreatitis, unless depleted of NK cells. In vivo treatment with soluble cytokine receptors suggested that interleukin 1 (IL‐1) and/or tumour necrosis factor α contribute to acinar necrosis in C57BL mice.
Effect of S‐adenosylmethionine versus tauroursodeoxycholic acid on bile acid‐induced apoptosis and cytolysis in rat hepatocytes
Authors: Benz  , Angermüller  , Klöters‐Plachky  , Sauer  , Stremmel  , Stiehl  
Published: March 2003

BackgroundS‐adenosylmethionine (SAMe) increases survival in alcoholic liver cirrhosis and may have a beneficial effect in cholestatic liver disease. SAMe repletes glutathione stores and protects tissues from oxygen free radicals. The effect of SAMe on bile acid‐induced apoptosis is unknown. In the present study the possible hepatoprotective effect of SAMe was evaluated and compared with that of tauroursodeoxycholic acid (TUDCA).MethodsPrimary rat hepatocytes treated with glycochenodeoxycholic acid (GCDCA) were used as a model for cholestasis‐induced hepatocellular damage, which served to study the effects of SAMe and TUDCA on bile acid‐induced apoptosis and cytolysis.ResultsSAMe reduced bile acid‐induced apoptosis but did not prevent bile acid‐induced cytolysis. Compared with SAMe, TUDCA was more efficient in reducing apoptosis due to toxic bile acids. The combination of SAMe and TUDCA had additive effects in reducing apoptosis.ConclusionThe reduction in bile acid‐induced apoptosis by SAMe may represent one of the factors responsible for its beneficial effects in the treatment of liver diseases.
Functional and structural properties of Na+/K+‐ATPase enzyme in neonatal erythrocytes
Authors: Vásárhelyi  , Vér  , Nobilis  , Szabó  , Tulassay  
Published: March 2003

BackgroundThe Na+/K+‐pump is the main regulator enzyme of intracellular monovalent cation concentration. There are only limited data available concerning its structure and function in healthy neonates, in comparison with data available regarding its structure and function in children.Patients and methodsSamples of 100 μL of anticoagulated blood were taken from 53 healthy neonates (age under 6th postnatal day, median age 3.5 days) and 61 healthy children (median age 12.4 months, range 6–36 months,). The Na+/K+‐ATPase activity, its sensitivity to ouabain (a digoxin‐analogue substance) and the expression of Na+/K+‐ATPase subunit isoforms were determined.ResultsThe enzyme activity (429.2 ± 17.1 versus 295.5 ± 10.2 U, P < 0.001) and I50 value for ouabain inhibition (1.50 ± 0.10 versus 0.96 ± 0.10 μmol L–1, P < 0.05) was higher in neonates. More α1 subunits (relative density: 1.16 ± 0.10 versus 0.75 ± 0.03, P < 0.001) and higher α1/α2 ratio (4.14 ± 0.21 versus 2.02 ± 0.16, P < 0.01) were detected.ConclusionThis is the first study demonstrating changes of Na+/K+‐ATPase molecules not only in enzyme activity, but also on protein level. Our results might contribute to the understanding of the resistance of neonatal cell membranes toward the pharmacodynamic actions of cardiac glycosides.
Induction and enhancement of normal human megakaryocyte polyploidization are concomitant with perturbation in the actin metabolism
Authors: Baatout  , Chatelain  , Staquet  , Symann  , Chatelain  
Published: March 2003

BackgroundMegakaryocyte polyploidization results from the lack of cytoplasmic separation while the nucleus keeps dividing.MethodsTo investigate the role of actin in the megakaryocyte polyploidization, three human cell lines with megakaryocytic properties (DAMI, HEL and K562) were incubated in the presence of cytochalasin B, an inhibitor of actin polymerization. These data were then compared with normal megakaryocytes.ResultsCompared with control conditions, cells cultured in the presence of cytochalasin B revealed an augmentation of cell size and ploidy and an arrest of cell proliferation. The expression of platelet membrane glycoproteins Ib, IIb/IIIa, IIIa and thrombospondin and transferrin receptors was augmented after treatment with cytochalasin B. Physiologically, the role of actin in inducing polyploidization could be related to an imbalance between G‐ and F‐actins. To test this hypothesis, we measured G‐, F‐ and total actin in cytochalasin B‐treated cells. Actin was found to be increased significantly in cytochalasin B‐treated DAMI and HEL cell lines. In contrast, the G/F‐actin ratio was not affected by cytochalasin B. To confirm these actin changes in physiological megakaryocytopoiesis, G‐ and F‐actin contents were then estimated in normal megakaryocytes. The G‐ and F‐actin contents of megakaryocytes from eight normal patients exponentially decreased from 2 to 128n, whereas the total actin content per cell kept increasing. The G/F ratio was unaffected.ConclusionPolyploidization of human megakaryocytes results from either a diminution of actin synthesis or an increased actin turnover, which in turn possibly abrogates the formation of the actin cleavage furrow in telophasis.