bluuebunny/crossref_metadata_2025 huggingface dataset:
Interlaboratory reproducibility of the immunocytochemical assessment of oestrogen and progesterone receptors and proliferative activity in fine needle aspiration of breast cancer
Authors: CONFORTINI M. , CAROZZI F. , BOZZOLA L. , MICCINESI G. , MIRRI F. , MOTTOLESE M. , NOFERINI D. , NIZZOLI R. , TINACCI G. , VOCATURO A. , ZAPPA M. , MADDAU C.
Published: March 2003

Interlaboratory reproducibility of the immunocytochemical assessment of oestrogen and progesterone receptors and proliferative activity in fine needle aspiration of breast cancer

The purpose of this study was to establish the interlaboratory reproducibility of immunocytochemical analysis of oestrogen (ER) and progesterone (PR) expression and Mib1 growth fraction on fine needle aspiration (FNA) smears. A set of 44 immunostained slides for ER, PR and Mib1 were randomly selected from the archives of the Center for the Study and Prevention of Cancer (CSPO) of Florence, Italy, and submitted for reading to 6 Italian laboratories. The generalized kappa statistic was used as an indicator of agreement among the six laboratories. A good correlation for ER and PR was evident. For Mib1 the results showed some discrepancies. In addition to adequate standardization of procedures, these data confirm that the reliability of the immunocytochemistry is strictly linked to accurate analysis of the results.
Nutritional reserves regulate male participation in Mediterranean fruit fly leks
Authors: YUVAL BOAZ , KASPI ROY , SHLOUSH SHLOMIT , WARBURG MEIRAV S.
Published: March 2003

1. The mating system of Mediterranean fruit flies (Ceratitis capitata, Diptera: Tephritidae), is based on male leks that form on the foliage of trees. Following observations that not all males participate in leks, the hypotheses that (a) small males are absent from leks and (b) males with inadequate nutrient reserves are unable to participate in leks were examined.

2. The size and weight of lekking males (n = 183) and resting males captured at the same time in the vicinity of leks (n = 148) were established. In addition, using biochemical techniques, the amounts of sugar, glycogen, lipid and protein in each individual were established quantitatively.

3. There was no significant size difference between lekking and resting males. However, lekking males were significantly heavier and contained significantly more sugars and protein than resting males.

4. In conclusion, leks are exclusive, and only males with adequate nutritional reserves may join. Thus, in this species, reproductive success is closely linked to foraging success.
Social biology and sex ratios of the eusocial gall‐inducing thrips Kladothrips hamiltoni
Authors: Kranz Brenda D. , Schwarz Michael P. , Mound Laurence A. , Crespi Bernard J.
Published: March 2003

1. Thrips comprise the only order besides Hymenoptera where females are diploid and males are haploid. This makes them useful insects for studying the roles of kin selection and ecology in social evolution.

2. Kladothrips hamiltoni is one of six species of Australian gall‐inducing thrips that have been identified as eusocial. Galls are initiated by a single foundress, who rears her brood and remains within the enclosed gall for life. The adults of both sexes of her first brood cohort are morphologically distinct from the second generation, comprising a nondispersing soldier caste. The foundress and sib‐mated soldiers jointly produce a second, dispersing generation, approximately 60–80% of which are produced by the soldiers. Mean per capita egg production of female soldiers is less than 33% that of the foundress.

3. Adult eclosion of soldiers is protandrous but the overall sex ratio of the soldiers lacks bias (52% male). Protandry of soldiers increases the probability that female soldiers will be inseminated soon after their eclosion and therefore lay fertilised, female eggs. The lack of bias could be due to a balance between local resource competition and local mate competition. Gender‐specific defensive behaviour of soldiers with their enemies may also be important in explaining this unexpected sex ratio.

4. The dispersing generation has an overall extreme female bias (5.6% male). Soldier incest increases relatedness between females more than between males, such that the foundress is more related to her granddaughters than her daughters, and female soldiers are more related to their daughters than their sons (assuming within‐gall relatedness < 1). A female bias in the offspring of soldiers should be preferred by both the foundress and soldiers as they are more related to soldier‐produced dispersing females than any other thrips in the gall. Female bias in the dispersing generation will also reduce local mate competition between males. Both soldier incest and local mate competition may therefore contribute to the extreme female bias in the dispersing generation.

5. Selection pressures for sociality in gall‐inducing thrips appear to be more similar to those in gall‐inducing aphids and naked mole rats than to those in Hymenoptera.
The influence of host plant variation and intraspecific competition on oviposition preference and offspring performance in the host races of Eurosta solidaginis
Authors: Craig Timothy P. , Itami Joanne K. , Shantz Cathleen , Abrahamson Warren G. , Horner John. D. , Craig James V.
Published: March 2003

1. A series of experiments was conducted to measure the impact of plant genotype, plant growth rate, and intraspecific competition on the oviposition preference and offspring performance of the host races of Eurosta solidaginis (Diptera: Tephritidae), a fly that forms galls on Solidago altissima and Solidago gigantea (Asteraceae). Previous research has shown that both host races prefer to oviposit on their own host plant where survival is much higher than on the alternate host plant. In this study, neither host race showed any relationship between oviposition preference and offspring performance in choosing among plants of their natal host species.

2. The larval survival of both host races differed among plant genotypes when each host race oviposited on its natal host species. In one experiment, altissima host race females showed a preference among plant genotypes that was not correlated with offspring performance on those genotypes. In all other experiments, neither the altissima nor gigantea host race demonstrated a preference for specific host plant genotypes.

3. Eurosta solidaginis had a preference for ovipositing on rapidly growing ramets in all experiments, however larval survival was not correlated with ramet growth rate at the time of oviposition.

4. Eurosta solidaginis suffered high mortality from intraspecific competition in the early larval stage. There was little evidence, however, that females avoided ovipositing on ramets that had been attacked previously. This led to an aggregated distribution of eggs among ramets and strong intraspecific competition.

5. There was no interaction among plant genotype, plant growth rate, or intraspecific competition in determining oviposition preference or offspring performance.
A comparison of bumblebees’ movements in uniform and aggregated distributions of their forage plant
Authors: Cresswell James E.
Published: March 2003

1. Movements by bumblebees Bombus lapidarius were studied in arrays of plants of oil‐seed rape Brassica napus cv Westar. In the arrays, plants were arranged into either a uniformly dispersed configuration or a patchily dispersed configuration.

2. Progress across an array was measured as the distance bumblebees had moved away from an original plant location after eight subsequent, successive plant visits. Movements were analysed in units of both metres and inter‐plant spaces. In both units, bumblebees progressed more slowly across patchily dispersed arrays.

3. Plant dispersion had a detectable effect on certain components of bees’ individual inter‐plant moves (e.g. move length in metres) but not on others (e.g. mean turning angle). In some cases, the effects of aggregation on the components of individual moves were probably too small to detect statistically and only emerged in their cumulative effect on bees’ progress.

4. Over short sequences of plant visits, bumblebees revisited plants rarely, but the frequency of revisits was almost twice as high in patchy arrays as in uniform arrays, and economic penalties may result from foraging among highly aggregated plants.

5. The effects of plant dispersion on pollinator movements detected in this study are unlikely to have a major impact on pollen transfer in B. napus because differences in pollinator progress only emerged after several successive inter‐plant flights away from a potential pollen source, by which time the limited extent of pollen carryover in this species means that fertilisations from the source plant would be very rare.
Marginal range expansion in a host‐limited butterfly species Gonepteryx rhamni
Authors: Gutiérrez David , Thomas Chris D.
Published: March 2003

1. The British distribution of the butterfly Gonepteryx rhamni (L.) follows closely the range of its natural host plants, Rhamnus catharticus L. and Frangula alnus Miller, suggesting that it is one of the few British butterflies that has a host‐limited distribution. In North Wales, this species has its range margin, and it was recorded only occasionally in a 35‐km2 area prior to the 1980s. Frangula alnus bushes were planted in the area in about 1986, allowing the hypothesis that G. rhamni would expand its range following increased host plant availability to be tested.

2. From 1996 to 1998, the distribution of the butterfly and its host plants, R. catharticus (native), Rhamnus alaternus L. (introduced), and F. alnus (introduced to the area but native to Britain), was mapped in the study area. It was found that the butterfly was more widespread than any of its host plants. Frangula alnus was the most widespread of the host plants, and received most eggs, suggesting that the carrying capacity of the habitat would have increased substantially following the planting of this species. Gonepteryx rhamni was able to complete its lifecycle on both introduced species in the study area.

3. A mark–release–recapture study showed that adult G. rhamni moved an average of 512 m, and 50% of movements were further than 400 m; these values are underestimates. The relatively high mobility of this species suggests that it probably perceives host plants and nectar sources as resource patches (patchy population) in this fragmented landscape, and this population now represents a satellite population of the butterfly's main distribution in Britain.

4. The results presented here confirm empirically the host‐limited distribution of G. rhamni, which expanded following the planting of extra host plants.
Associations between host migration and the prevalence of a protozoan parasite in natural populations of adult monarch butterflies
Authors: Altizer Sonia M. , Oberhauser Karen S. , Brower Lincoln P.
Published: March 2003

1. Monarch butterfliesDanaus plexippus(L.) (Lepidoptera: Nymphalidae) are susceptible to infection by the obligate protozoan parasiteOphryocystis elektroscirrha(McLaughlin and Myers) (Apicomplexa: Neogregarinida). Because monarchs form resident and migratory populations in different parts of the world, this host–parasite system provides the opportunity to examine how variation in parasite prevalence relates to host movement patterns.

2. Parasite prevalence was evaluated using 14 790 adult monarchs captured between 1968 and 1997. Comparison of three populations in North America indicated that parasite prevalence is associated negatively with host dispersal distances. A continuously breeding, nonmigratory population in southern Florida showed high prevalence (over 70% heavily infected). The western population migrates moderate distances to overwintering sites on the Pacific Coast and has intermediate prevalence (30% heavily infected). The eastern migratory population, which travels the longest distance to Mexican overwintering sites, has exhibited less than 8% infection throughout the past 30 years.

3. Variation in parasite loads within North American migratory populations was investigated to determine whether the prevalence of heavy infection and average parasite loads declined during migration or overwintering. Average parasite loads of summer‐breeding adults in western North America decreased with increasing distance from overwintering sites. This suggests that heavily infected monarchs are less likely to remigrate long distances in spring. No differences in the frequency of heavily infected adults were found among eastern or western North American monarchs throughout the overwintering period, however, suggesting that this parasite does not affect overwintering mortality.

4. Changes in the prevalence of monarchs with low parasite loads demonstrate that spore transfer occurs during migration and overwintering, possibly when adult butterflies contact each other as a result of their clustering behaviour.

5. This study of geographical and temporal variation inO. elektroscirrhaamong populations ofD. plexippusdemonstrates the potential role of seasonal migration in mediating interactions between hosts and parasites, and suggests several mechanisms through which migratory behaviour may influence parasite prevalence.
Fitness and body size in mature odonates
Authors: Sokolovska Natalia , Rowe Locke , Johansson Frank
Published: March 2003

The relationship between body size and fitness components in odonates was examined using a meta‐analysis of 33 published studies. There was a positive and significant overall effect of body size on mating rate and lifetime mating success among males. There was also a weaker but still significant positive effect of body size on survivorship of males. The relationship between body size, mating rate, longevity, and lifetime mating success differed significantly between males of territorial and nonterritorial species. The effect of body size was significant for all fitness components in territorial species but significant only for longevity and lifetime mating success in nonterritorial species. Effect sizes appeared to be strongest on longevity in both sexes, and on male mating rate in territorial species. Other effect sizes, even when significant, were small. Despite a much smaller data set, female fitness also increased significantly with body size. Both clutch size and longevity showed a significant positive relationship with body size. These results suggest that there is a general fitness benefit to large size in odonates. Nevertheless, significant heterogeneity is apparent in this effect, which can be attributed to sex, mating system, and fitness component. Finally, these analyses point to inadequacies in the current data that need further study before the potentially rich patterns in size effects on fitness can be explored more thoroughly.
An economic model of the limits to foraging range in central place foragers with numerical solutions for bumblebees
Authors: Cresswell James E. , Osborne Juliet L. , Goulson David
Published: March 2003

1. A model is described that evaluates the maximum economic foraging range in central place foragers by using optimality criteria to discriminate between foraging sites at different distances from the forager's central place.

2. The basic model can be varied to suit foragers that optimise either their rate of net energy uptake or their foraging efficiency.

3. The model requires specification of the time and energy budgets of travel and foraging, and of the rewards obtainable at potential foraging sites.

4. The specific case of bumblebees, whose foraging ranges are poorly known, is considered.

5. Numerical solutions of the model for parameter values that represent bumblebees and their forage predict economic foraging ranges exceeding several kilometres. The model demonstrates that economics alone can explain extensive flight ranges in bees.
Aphid‐induced reduction of shoot and root growth in Douglas‐fir seedlings
Authors: Smith J. P. , Schowalter T. D.
Published: March 2003

1. The short‐ and long‐term effects of photosynthate removal by sap‐sucking herbivores on plant growth were examined by experimentally manipulating densities of an aphid Cinara pseudotsugae (Wilson) on 2‐year‐old Douglas‐fir seedlings Pseudotsuga menziesii (Mirb.) Franco under greenhouse conditions. An 18‐week test was conducted to determine short‐term effects. Effects of long‐term aphid feeding were examined by exposing seedlings to aphid feeding for two consecutive growing seasons. A third experiment evaluated the extent of recovery during 1 year following a single season of aphid feeding. At least 35 seedlings were used in each test.

2. Volume and dry weight of both shoots and roots decreased significantly with increasing aphid feeding in all three experiments.

3. The most significant and severe aphid effect was reduced root tissue density, suggesting carbohydrate depletion due to translocation from roots to shoots.

4. There was no sign of recovery, of either root or shoot growth, during the year following one season of feeding.

5. The results of this study indicate that short‐term feeding by aphids can affect plant growth and structure for a relatively long time.
Spiders and harvestmen as gastropod predators
Authors: Nyffeler Martin , Symondson William O. C.
Published: March 2003

1. Reports are reviewed of gastropod feeding (malacophagy) by spiders and harvestmen. Although the standard textbooks on arachnids recognise the importance of gastropods as prey of harvestmen, none apparently refers to malacophagy by spiders. A review of several hundred papers on spider feeding habits revealed that species from several families kill and devour slugs and snails in the laboratory and/or field.

2. Malacophagy has been reported most frequently among mygalomorph spiders, and can make up a substantial proportion of the diets of some species, however gastropods make up an insignificant percentage of the prey of most araneomorph spiders. The spiders that eat gastropods are species with broad diets composed predominantly of arthropod prey. No species of spider appears to feed exclusively on gastropod prey.

3. Harvestmen from several families have broad diets that often include gastropods. Several species of the family Trogulidae and at least one species of the family Ischyropsalididae [Ischyropsalis hellwigi (Panzer)] are specialised gastropod predators. The trogulids are slender animals that attack the snail through the shell aperture (shell intruders). Ischyropsalis hellwigi, on the other hand, can crush snail shells with its powerful chelicerae (shell breakers).

4. The review highlights apparent convergent evolution by harvestmen and Carabidae of two mutually exclusive morphologies found among gastropod predators. It also suggests that there is an urgent need for systematic studies to be conducted to establish the extent and ecological importance of malacophagy in natural and anthropogenically altered habitats.
Gamete production and sexual size dimorphism in an insect (Orchesella cincta) with indeterminate growth
Authors: Ernsting G. , Isaaks J. A.
Published: March 2003

Abstract 1. The relationship of growth and body size with reproductive effort in animal species has been studied much less for males than for females. This imbalance applies to Orchesella cincta (L.) (Collembola), an insect with indeterminate growth, in which egg production is related positively to body size and negatively to growth.

2. To allow a comparison of the reproductive effort of male and female O. cincta, development and growth in immature stages of both sexes, and growth and spermatophore production for adult males were studied.

3. Embryonic development time and hatchling size did not differ between prospective males and females, but from hatching on the trajectories diverged, with males growing more slowly and maturing earlier and at a much smaller body size than females.

4. Neither the number of spermatophores deposited in the first adult instar (= inter‐moult period) nor the total number of spermatophores deposited during seven instars was related to body size or growth.

5. Differences in growth rate between instars with and without spermatophore deposition indicated that the physiology of spermatophore production inhibits growth, which, however, was compensated for during the next instar.

6. The difference in the relationship of gamete production with body size and growth between males and females explains the divergence of their size at maturity.
Migration and Allee effects in the six‐spot burnet mothZygaena filipendulae
Authors: Menéndez Rosa , Gutiérrez David , Thomas Chris D.
Published: March 2003

Abstract1. Migration into local populations may increase the likelihood of persistence but emigration may decrease the persistence of small and isolated populations. The dispersal behaviour of a day‐flying mothZygaena filipendulaewas examined to determine whether emigration is correlated positively or negatively with population size and host plant density.

2. A mark–release–recapture study showed that most moths moved small distances (< 40 m on average) and only 6% of movements were > 100 m.

3. Twenty‐five individuals moved between populations, a measured exchange rate of 8%. Moths were more likely to move between patches that were close together and they moved to relatively large patches.

4. The fraction of residents increased with increasing population size in the patch and increasing host plant cover. Relatively high proportions of individuals left small patches with small moth populations.

5. Moths released in grassland lackingLotus corniculatus(the host plant) tended to leave the area and biased their movement towards host plant areas, whereas those released within an area containingL. corniculatustended to stay in that area.

6. Biased movement away from small populations and areas of low host plant density (normally with low population density) was found. This migration‐mediated Allee effect is likely to decrease patch occupancy in metapopulations, the opposite of the rescue effect. The effects on metapopulation persistence are not known.
An experimental examination of the effects of habitat quality on the dispersal and local abundance of the butterfly Parnassius smintheus
Authors: Matter Stephen F. , Roland Jens
Published: March 2003

Abstract 1. Nectar flower abundance was manipulated through flower removal, and sex ratio was manipulated by moving individual butterflies within a series of nine alpine meadows. The movement and abundance of the butterfly Parnassius smintheus in the meadows were monitored using mark–release–recapture methods.

2. A total of 937 butterflies, 698 males and 239 females, was captured. There were 223 observed between‐meadow movements. Fifty‐two per cent of males and 35% of females moved among meadows.

3. The immigration of male butterflies was related positively to nectar flowers, host plant abundance, and female butterflies. Male emigration was not affected by any of the treatments. The number of males captured was related positively to nectar flowers and host plants but not affected by sex ratio. The number of resident male butterflies was greater in meadows containing flowers and was related positively to host plant abundance, but unaffected by sex ratio.

4. Flower removal, sex ratio, and abundance of Sedum had no significant effect on the abundance, movement, or residence time for female butterflies, in part due to small sample size.

5. The fact that males immigrate to higher quality meadows suggests that male butterflies are assessing meadow quality, either by sampling meadows or potentially from a distance using olfactory cues.
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.
Susceptibility of stone‐fruit rootstocks, rose and grapevine to Agrobacterium radiobacter var. tumefaciens in Arab Mediterranean countries
Authors: Benjama A. , Boubaker A. , Khlief H. , Krimi Z. , Nesme X. , López M. , Zoina A.
Published: March 2003

Crown gall was found in all fruit‐growing areas in Algeria, Jordan, Morocco and Tunisia. In the last three countries, shoot and/or root inoculation of stone fruits, rose and/or grapevine (according to country) with Agrobacterium radiobacter var. tumefaciens showed that all species were susceptible independently of country and origin of bacterial strains, with the exception of the Beldi land race of apricot in Morocco, which was tolerant. The level of susceptibility varied according to the strains used.
Gastroduodenal permeability in Crohn's disease
Authors: Püspök  , Oberhuber  , Wyatt  , Maier‐Dobersberger  , Hammer  , Pfeffel  , Wrba  , Pötzi  , Vogelsang
Published: March 2003

Background

Gastric 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.

Methods

All subjects underwent oesophagogastroduodenoscopy with biopsies of all investigated parts. Thirty‐two Helicobacter pylori‐positive patients were excluded from further analyses.

Results

Gastroduodenal 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%.

Conclusion

In 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

Methods

In 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.

Results

Perfusion 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.

Conclusion

We 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

Background

Alcohol‐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.

Methods

Whole (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.

Results

Three 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.

Conclusion

This 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

Background

HMG‐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.

Methods

Thirty‐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.

Results

All 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.

Conclusion

The 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

Background

The 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.

Results

In 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.

Conclusion

We 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.
Chromogranin A: its clinical value as marker of neuroendocrine tumours
Authors: Nobels  , Kwekkeboom  , Bouillon  , Lamberts
Published: March 2003

Chromogranin A (CgA) belongs to a family of secretory proteins that are present in dense‐core vesicles of neuroendocrine cells. Owing to its widespread distribution in neuroendocrine tissues, it can be used as an excellent immunohistochemical marker of neoplasms of neuroendocrine origin. It can also serve as serum marker of neuroendocrine activity because it is co‐released with the peptide hormone content of the secretory granules. The serum concentration of CgA is elevated in patients with various neuroendocrine tumours. Elevated levels are strongly correlated with tumour volume. Although its sensitivity and specificity cannot compete with that of the specific hormonal secretion products of most of these tumours, it can nevertheless have useful clinical applications. Neuroendocrine tumours for which no peptide marker is available usually retain the capacity to secrete CgA. CgA can thus be used as serum marker for these so‐called ‘non‐functioning’ endocrine tumours. Moreover, in patients with carcinoids and phaeochromocytomas, CgA is a more stable and thus more easily manageable marker than plasma levels of respectively serotonin and catecholamines and their urinary metabolites. Its role as an important general neuroendocrine marker may be extended in the future by the development of immunoscintigraphy of membrane‐bound CgA, allowing in vivo visualization of neuroendocrine neoplasms.
Factors influencing the effects of murine cytomegalovirus on the pancreas
Authors: Price  , Baxter  , Allcock  , Papadimitriou
Published: March 2003

Background

As 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.

Results

Inflammation 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

Background

S‐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).

Methods

Primary 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.

Results

SAMe 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.

Conclusion

The 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

Background

The 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 methods

Samples 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.

Results

The 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.

Conclusion

This 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.