bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavioural changes in Schistocerca gregaria following infection with a fungal pathogen: implications for susceptibility to predation
Authors: Arthurs Steven , Thomas Matthew B.
Published: March 2003

1. Field observations have indicated that infection of locusts and grasshoppers by the fungal entomopathogen Metarhizium anisopliae var. acridum may result in a substantial increase in the host's susceptibility to predation, before death is caused directly by the disease.

2. Laboratory experiments were conducted to examine how the behaviour of the desert locust Schistocerca gregaria Forskål changes following infection by M. anisopliae var. acridum to explore some potential mechanisms underlying this phenomenon.

3. In the first experiment, which involved monitoring general locust activity in small cages throughout the disease incubation period, infected locusts were observed to increase locomotion and bodily movement from 3 days after infection until death (average survival time of 11 days). There was some evidence of reduced feeding and mating behaviour following infection.

4. In a second experiment, locusts were exposed individually to a simulated predator attack and the initiation and strength of any escape responses were measured. Infected locusts were observed to have a reduced escape capability (both the propensity to escape and the strength of the response). In contrast to the relatively early changes in general activity observed in the first experiment, this was only apparent at the late stages of infection shortly before death.

5. Both an increase in movement and general apparency early in the infection process, and reduced escape capability late on, suggest mechanisms whereby the susceptibility of locusts and grasshoppers to predation might be enhanced following infection with M. anisopliae var. acridum.
Variability in egg‐to‐adult development time in the bee Ptilothrix plumata and its parasitoids
Authors: Martins Rogério Parentoni , Guerra Sidnei Tadeu Mendes , Barbeitos Marcos Soares
Published: March 2003

Summary

1. Ptilothrix plumata (Hymenoptera) is a neotropical solitary bee that nests in bare, sandy soils. Data on the biology and behaviour of this species are provided. Egg‐to‐adult development time of a neotropical solitary bee and its parasitoids is quantified for the first time.

2. The bee showed huge variability in egg‐to‐adult development time. There are two categories of eggs relative to adult emergence. The same season eggs are those from which adults emerge in the same reproductive season in which the eggs were laid. Adults from next season eggs emerge in the next dry reproductive season. This variability in egg‐to‐adult development time is reached through prepupal diapause. The bee larval parasitoids Leucospis genalis (Hymenoptera) and Anthrax sp. (Diptera) showed similar range in their development times. The data show that diapause is controlled by season.

3. By synchronising adult emergence, this variability in egg‐to‐adult development time facilitates mate finding, and population recruitment is a consequence of the bees avoiding the unfavourable reproductive season.
Apparent widespread gene flow in the predominantly flightless planthopper Tumidagena minuta
Authors: Peterson Merrill A. , Denno Robert F. , Robinson Laura
Published: March 2003

1. To determine whether dispersal biology can predict the pattern of population‐genetic variation among insect populations accurately, allozyme variation was assayed for populations of a saltmarsh planthopper, Tumidagena minuta, in which > 99% of the adults are flightless.

2. The pattern of genetic isolation by distance in T. minuta was compared with that in other insects, to determine whether it was similar to isolation by distance in other sedentary insects.

3. In contrast to predictions, the pattern of isolation by distance in T. minuta was most similar to that seen in the most mobile insects in a recent review of population‐genetic variation in insects. Furthermore, population‐genetic subdivision over a spatial scale of > 400 km was weak.

4. Possible causes of the apparent contradiction between dispersal biology and population‐genetic structure in this species are discussed. The results for T. minuta highlight the fact that although mobility is generally correlated with gene flow in insects, studies of population‐genetic variation must be combined with direct studies of dispersal to understand fully the degree to which populations exchange individuals.
Egg deposition patterns of fig pollinating wasps: implications for studies on the stability of the mutualism
Authors: Jousselin Emmanuelle , Hossaert‐Mckey Martine , Vernet Didier , Kjellberg Finn
Published: March 2003

1. Fig pollinating wasps (Agaonidae) enter Ficus inflorescences (figs), oviposit in some of the flowers, and pollinate in the process. Each larva completes its development within a single flower. In most cases, an inflorescence entered by a wasp will represent its only egg‐laying site. The mechanisms that prevent pollinating wasps from exploiting all the flowers inside a fig are not understood. In this study, hypotheses about flower use by pollinating fig wasps were tested by investigating egg deposition patterns in three species.

2. Either one or three wasps were introduced into figs. The figs were then harvested. Serial sections allowed assessment of the presence or absence of a wasp egg in a sample of flowers in each fig. The overall proportion of flowers with eggs and the spatial distribution of eggs were then compared in single wasp figs and three foundress figs.

3. In all species, the proportion of flowers with a wasp egg increased with foundress number but less than three‐fold.

4. In all species, at least in single foundress figs, flowers near the fig cavity were more likely to receive a wasp egg than were flowers near the fig wall.

5. In two species, when the number of foundresses was multiplied by three, there was an increase in the use of flowers near the fig wall, while in the third species, the increase was spread evenly among flowers.

6. Factors affecting wasp egg deposition patterns and the potential of investigating such patterns for studying the stability of the mutualism are discussed.
Effects of meadow suitability on female behaviour in the alpine butterfly Parnassius smintheus
Authors: Fownes S. , Roland J.
Published: March 2003

Abstract  1. Many butterfly populations persist in networks of naturally fragmented habitat patches. Movement and reproductive decisions made by adult females are critical to the persistence of these populations because colonisation of extinct habitat patches in the network requires emigration of fecund adult females from their natal meadow and their subsequent establishment in the extinct patch.

2. Movement and oviposition behaviours of mated Parnassius smintheus females released in suitable meadows (a good‐ and a poor‐quality meadow) and an unsuitable meadow were compared, to determine whether adult females consider meadow suitability for their offspring despite frequent oviposition events off the larval host plant.

3. Bootstrap and correlated random walk analyses of female step lengths and turn angles demonstrated that females flew more randomly in the unsuitable meadow than in the suitable meadows. Although females tended to turn the sharpest angle between landing sites in the good‐quality meadow, and fly the smallest distance between landing sites and displace the smallest distance from the release site in the suitable meadows, no significant differences were detected in turn angle, step length, and dispersal rates between suitable and unsuitable meadows.

4. Results from female flight observations and a caged oviposition study suggest that females lay significantly more eggs in suitable habitat than in unsuitable habitat despite not ovipositing on the host plant, and support the above findings.

5. Movement and oviposition behaviours of adult female P. smintheus promote their retention within meadows that can support their offspring.
Testing for context‐dependence in a processing chain interaction among detritus‐feeding aquatic insects
Authors: Daugherty Matthew P. , Juliano Steven A.
Published: March 2003

Abstract 1. Scirtid beetles may benefit mosquitoes Ochlerotatus triseriatus (Say) by consuming whole leaves and leaving behind fine particles required by mosquito larvae. Such interactions based on the sequential use of a resource that occurs in multiple forms are known as processing chains.

2. Models of processing chains predict that interactions can vary from commensal (0, +) to amensal (0, –), depending on how quickly resource is processed in the absence of consumers.

3. The scirtid–O. triseriatus system was used to test the prediction derived from processing chain models that, as consumer‐independent processing increases, scirtids benefit mosquitoes less. Consumer‐independent processing rate was manipulated by using different leaf species that vary in decay rate, or by physically crushing a single leaf type to different degrees.

4. Although scirtids increased the production of fine particles, the effects of scirtids on mosquitoes were weak and were not dependent on consumer‐independent processing rate.

5. In the leaf manipulation experiment, a correlation between scirtid feeding and consumer‐independent processing was detected. Numerical simulations suggest that such a correlation may eliminate shifts from commensal to amensal at equilibrium; because mosquito populations are typically not at equilibrium, however, this correlation may not be important.

6. There was evidence that mosquitoes affected scirtids negatively, which is inconsistent with the structure of processing chain interactions in models. Processing chain models need to incorporate more detail on the biology of scirtids and O. triseriatus, especially alternative mechanisms of interaction, if they are to describe scirtid–O. triseriatus dynamics accurately.
Mating behaviour and light conditions cause seasonal changes in the dispersal pattern of the satyrine butterfly Lethe diana
Authors: Ide Jun‐Ya
Published: March 2003

1. The spatial arrangement of resources and climatically favourable sites affects the dispersal pattern of butterflies.

2. The microdistribution of the satyrine butterfly Lethe diana changes seasonally, meaning that the relative spatial arrangement of resources also changes seasonally. The seasonal change in the dispersal pattern of this butterfly was studied.

3. Males of the May–June generation tended to stay in a restricted habitat patch while females of the same generation did not. A number of the May–June generation males became resident at prime forest edge sites, where a territorial behaviour that was rarely seen in other generations was prevalent. Females of the May–June generation moved to these territorial sites for mating but left after copulation to avoid male harassment; their residency was therefore weak.

4. In both sexes, the July–August generation tended to be more mobile than the September–October generation. This was because the July–August generation butterflies utilised dark environments for thermoregulation and, because these conditions were widespread throughout the forest, the butterflies were able to move widely. The September–October generation, however, preferred intermediate light conditions, which tended to be restricted to the forest edge; as this was a relatively small area, butterfly movement was restricted.
Natural enemy ravine revisited: the importance of sample size for determining population growth
Authors: Jarošík Vojtěch , Honěk Alois , Dixon Anthony F. G.
Published: March 2003

Abstract.1. The population growth of three aphid species,Metopolophium dirhodum(Walker),Rhopalosiphum padi(L.), andSitobion avenae(F.), on winter wheat, was analysed by regression. The calculations were based on censuses of aphids made in 268 plots at 3‐ or 7‐day intervals for 10 years on leaves and 6 years on ears. The calculations were made separately for each plot each year, then repeated on the pooled data from all plots monitored in a year.

2. At the level of individual plots, no population growth was detected at very low densities. At high densities, the populations grew exponentially and the growth rates did not decrease with increasing aphid density.

3. Significant growth was always detected in the pooled data. These growth rates decreased significantly at the highest densities. Field estimates of the intrinsic rate of increase derived from these data ranged from 0.010 to 0.026 forM. dirhodum, 0.0071–0.011 forR. padi, and 0.00078–0.0061 and 0.0015–0.13 forS. avenae, on leaves and ears respectively.

4. The apparent lack of growth in the individual plots at low densities is attributable to small sample size. It is concluded that thenatural enemy ravinein the population dynamics of cereal aphids, identified by Southwood and Comins (1976), is a consequence of low population densities at which population increase is undetectable unless very large samples are taken.
Viruses and viroids of stone fruits in Syria
Authors: Ismaeil F. , Myrta A. , Ghanem‐Sabanadzovic N. Abou , Al Chaabi S. , Savino V.
Published: March 2003

Field surveys were carried out in the main stone fruit‐growing areas of Syria to evaluate the sanitary status of mother blocks, varietal collections and commercial orchards. The presence of virus and virus‐like diseases was checked by enzyme‐linked immunosorbent assay (ELISA), sap transmission to herbaceous hosts, testing on the woody indicators Prunus persica cv. GF 305 and Prunus serrulata cv. Kwanzan and dot‐blot hybridization tests. A total of 1337 samples was tested by ELISA (444 apricot, 283 peach, 246 cherry, 222 almond and 142 plum). The overall mean infection rate was 13%, and the percentage infection level of single species was: peach 24%, cherry 16%, almond 13.5%, apricot 6%, plum 5%. The following viruses and viroids were detected: PNRSV, PDV, ACLSV, PPV, ApMV, PLMVd and HSVd1.
Détection du virus causant la maladie dite yellow leaf syndrome (YLS) sur la culture de la canne à sucre au Maroc
Authors: Nadif A. , Chriki N. , Ouhssine M.
Published: March 2003

La détection au Maroc d’une nouvelle maladie dite syndrome de jaunissement de feuilles ou yellow leaf syndrome (YLS) sur les cultivars de canne à sucre libérés contre Ustilago scitaminea met la canne à sucre face à un nouveau défi qui nécessite une autre approche dans la stratégie de lutte. Cette approche doit impérativement permettre d’éviter des situations alarmantes enregistrées dans d’autres pays tels que le Brésil ou les Etats‐Unis (Hawaii) où le YLS a causé des dégâts sévères aussi bien au niveau du rendement qu’au niveau de la qualité technologique et du sucre extractible.
Body composition and energy expenditure of patients with chronic cardiac failure
Authors: Steele  , Young  , Stevenson  , Maguire  , Livingstone  , Rollo  , Scrimgeour  , Rennie  , Nicholls
Published: March 2003

Background

Patients with acute cardiac failure have excess body water, and it is commonly assumed that this is also so in patients with stable chronic cardiac failure (CCF).

Methods

To investigate this, we measured total body water (TBW) using stable isotope dilution and single‐frequency bioelectrical impedance (BIA), and also extracellular volume (ECV) using bromide dilution in 12 patients with CCF and eight matched control subjects.

Results

TBW (kg−1 body weight) was similar in the two groups [median 18O dilution 53.2% (range 46.5–57.1%) in patients vs. 54.8% (47.9–62.7) in control subjects; BIA 56.6% (42.7–73.1) vs. 58.0% (52.0–68.6)]. ECV was also similar in the two groups [0.25 L kg−1 (0.20–0.29) vs. 0.25 (0.19–0.35)]. There was a strong correlation between stable isotope and BIA measurements of TBW for all subjects (r = 0.76), but BIA overestimated TBW by a mean difference of 2.4 kg (limits of agreement of –4.1 kg to +8.9 kg). Body fat content was similar in the two groups, whether measured by skinfold anthropometry, whole‐body densitometry or by 18O dilution. Resting energy expenditure (REE), calculated from indirect calorimetry, and total energy expenditure (TEE), calculated from the ratio of 2H to 18O elimination rate after drinking doubly labelled water, were also similar in the two groups.

Conclusion

It is concluded that the patients with stable CCF in this study had normal ECV and TBW, and so excess body water did not account for their persistent symptoms.
Measurement of free fatty acid kinetics during non‐equilibrium tracer conditions in man: implications for the estimation of the rate of appearance of free fatty acids
Authors: Riemens  , Dullaart  , J .F. Franssen  , Piers  , Reitsma  , Sluiter
Published: March 2003

Background

This study aimed to document the applicability and variability of free fatty acid (FFA) kinetic parameters during non‐equilibrium and equilibrium tracer conditions in man.

Methods

FFA kinetic parameters were assessed after an overnight fast in six healthy non‐obese and three obese subjects as well as in three patients with non‐insulin‐dependent diabetes mellitus (NIDDM) by infusion of [14C]‐palmitate of 60 min (study A) and 10 min duration (study B).

Results

The kinetic parameters estimated from the upstroke and downstroke of the plasma FFA specific activity curve (non‐equilibrium) were not statistically different within studies A and B. Furthermore, there were no significant differences in any of the FFA kinetic parameters between studies A and B. The averaged plasma levels of FFA obtained during the up‐ and downstroke from studies A and B were higher in obese subjects and NIDDM patients than in non‐obese subjects (P < 0.01). The averaged total rate of appearance (TRa) of FFA was higher in obese subjects than in non‐obese subjects (P < 0.02). The TRa and metabolic clearance rate (MCR), estimated from non‐equilibrium conditions, were about 25% higher than the apparent values obtained from steady‐state measurement in all subjects combined (P < 0.01), suggesting considerable recirculation of label from hydrolysis of labelled esterified fatty acids. Indeed, in three non‐obese subjects, the radiolabel in esterified fatty acids was approximately 50% of labelled FFA at 60 min of label infusion. The coefficients of variation of the kinetic parameters were consistently larger in study A than in study B.

Conclusion

FFA kinetic parameters can be estimated with sufficient precision using non‐equilibrium data from short‐term labelled palmitate infusion. Short‐term label infusion has the advantage that label recirculation is prevented and exposure to radiation is limited.
Lack of relationship between the PlA1/PlA2 polymorphism of platelet glycoprotein IIIa and premature myocardial infarction
Authors: Scaglione  , Bergerone  , Gaschino  , Imazio  , Maccagnani  , Gambino  , Cassader  , Di Leo  , Macchia  , Brusca  , Pagano  , Cavallo‐Perin
Published: March 2003

Background

The PlA1/PlA2 polymorphism of the platelet glycoprotein IIIa has been variably associated with an increased risk of coronary thrombosis.

Materials

We investigated the linkage between the PlA1/PlA2 polymorphism and the risk of myocardial infarction in 98 patients who suffered their first myocardial infarction at the age of 45 years or less and 98 well‐matched control subjects without coronary artery disease. Lipid parameters were measured using conventional methods of clinical chemistry; PlA genotypes were determined by polymerase chain reaction and restriction enzyme digestion.

Results

There was no significant difference in the prevalence of PlA2‐positive genotypes (either PlA1/PlA2 or PlA2/PlA2) between patients and control subjects (χ2 = 0.66, d.f. = 1, P = 0.41).

Conclusions

These results suggest that the PlA2 polymorphism of the platelet glycoprotein IIIa does not contribute to the genetic susceptibility to premature myocardial infarction.
Retention of fluorescent‐labelled chylomicron remnants within the intima of the arterial wall — evidence that plaque cholesterol may be derived from post‐prandial lipoproteins
Authors: Proctor  , L. Mamo
Published: March 2003

Plaque cholesterol is thought to be derived exclusively from low‐density lipoproteins that have become trapped and modified in the subendothelial space of arterial vessels. However, in this study we provide the first visual evidence that demonstrates that (a) remnants of post‐prandial lipoproteins rapidly penetrate arterial tissue; (b) efflux is not complete; and (c) focal accumulation of chylomicron remnants occurs within the subendothelial space. The arterial retention of chylomicron remnants is consistent with atherogenesis being in part a post‐prandial phenomenon.
In vitro culture growth of erythroid progenitors and serum erythropoietin assay in the differential diagnosis of polycythaemia
Authors: Shih  , Lee  , See  , Ou  , Dunn  , Wang  , Kuo  , Wu
Published: March 2003

Background

We assessed the in vitro culture growth of erythroid progenitors [burst forming unit‐erythroid (BFU‐E)] and serum erythropoietin (EPO) levels in different groups of polycythaemia to determine the discriminative power in the differential diagnosis of polycythaemia.

Methods

We used the methylcellulose culture technique to study the growth of endogenous erythroid colonies (EECs) and EPO‐dependent BFU‐E from bone marrow (BM) and/or peripheral blood (PB) cells from 40 patients with polycythaemia vera (PV), 13 with secondary polycythaemia (SP), 19 with pure erythrocytosis (PE), five with PE and PV evolution later (PE‐PV), and 12 with relative polycythaemia (RP). The serum EPO levels were measured by radioimmunoassay before treatment in 47 PV patients, 23 SP patients, 19 PE patients, five PE‐PV patients and 16 RP patients, as well as after treatment in 38 PV patients, five PE‐PV patients and 12 PE patients.

Results

The results of the erythroid progenitor culture assay showed that the numbers of EPO‐dependent BFU‐E in BM did not differ significantly among groups. The PB BFU‐E were significantly higher in PV than in SP or PE, and no statistical differences were found among patients with SP, PE and RP. There was a correlation between BM BFU‐E and PB BFU‐E in the individual PV and PE patients. EECs were present in all BM and PB cultures of untreated and phlebotomy‐treated PV and PE‐PV patients, but were absent in 6 of 17 PV patients who had received cytotoxic therapy. EECs were not found in SP, PE and RP. PB could substitute for BM in the EEC or the BFU‐E assay. Both pretreatment and post‐treatment serum EPO levels of PV and PE‐PV were similar, which were significantly lower than SP, PE or RP. The serum EPO levels in treated PV or PE‐PV patients who had normal haematocrit values were not significantly different from those in untreated patients. In contrast, the phlebotomy‐treated PE patients had significantly higher serum EPO values than untreated PE patients. In the differentiation between PV and PE, the sensitivity, specificity, positive predictive value and negative predictive value of post‐treatment serum EPO levels at a cut‐off level of 9 U L−1 were 74%, 92%, 97% and 52% respectively. The discriminative power of post‐phlebotomy serum EPO levels was even higher with a positive predictive value of 80% and negative predictive value of 92% for the prediction of PV evolution in patients with pure erythrocytosis of unknown origin.

Conclusion

The present study showed that apart from EEC assay, the post‐phlebotomy serum EPO level was a sensitive and specific parameter in the differential diagnosis of polycythaemia, in particular for the identification of PV among patients with unclassifiable polycythaemia.
Increased circulating cytokine receptors and ex vivo interleukin‐1 receptor antagonist and interleukin‐1β production but decreased tumour necrosis factor‐α production after a 5‐km run
Authors: Drenth  , Krebbers  , Bijzet  , Van Der Meer
Published: March 2003

Background

The purpose of this study was to examine the effect of a 5‐km run on blood leucocytes, acute‐phase proteins and cytokines. In addition, cytokines were measured in the supernatants from whole‐blood cell cultures incubated with lipolysaccharide (LPS).

Methods

Ten healthy, recreational trained, athletes (three women, seven men) volunteered for this investigation. Samples were drawn just before, immediately after and at 3 h, at 24 h and at 48 h after the race.

Results

Exercise induced a transient leucocytosis (P = 0.0002) and a mild acute‐phase reaction with increase in plasma C‐reactive protein (CRP) (P = 0.0115) but not in serum amyloid A (SAA) concentrations. Although plasma interleukin 6 (IL‐6) was undetectable and soluble interleukin‐1 receptor type II (IL‐1sRII) remained unchanged, interleukin‐1 receptor antagonist (IL‐1ra) concentrations were elevated directly after the race with a further increase at 3 h (P < 0.0001). Soluble tumour necrosis factor (TNF) receptors were increased immediately after the run, but the effect was more marked for sTNFr p55 (two‐fold increase; P < 0.0001) than for sTNFr p75 (1.16‐fold increase; P = 00007). In cell cultures, the LPS‐induced release of the inflammatory cytokines doubled for IL‐1β (P < 0.0001) and for IL‐1ra (P < 0.0001). In contrast, TNF‐α production decreased after the run, and a nadir was reached at 24 h (P < 0.0001).

Conclusion

These results suggest that a 5‐km run elicits both the production of acute‐phase mediators (leucocytosis and elevation of CRP) and anti‐inflammatory counter‐regulation as judged by the increase in circulating concentrations of IL‐1ra, sTNFr p55, and sTNFrp75 and down‐regulation of LPS‐stimulated TNF‐α production.
Mutations in the carboxy terminus of the β and γ subunits of the epithelial sodium channel are not present in patients with hypertensive crisis
Authors: Födinger  , Hirschl  , Schedler  , Herkner  , Bur  , Laggner  , Hörl  , Sunder‐Plassmann
Published: March 2003

Background

The pathophysiology of hypertensive crises is poorly understood. To date, no information is available about genetic determinants underlying the individual risk for development of hypertensive urgencies or emergencies. Recently, mutations in the β subunit (hβENaC) and the γ subunit (hγENaC) of the human epithelial sodium channel (hENaC) have been shown to result in excessive elevation of blood pressure in patients with Liddle's syndrome.

Methods

Using polymerase chain reaction and direct sequencing of amplification products we have screened 90 consecutive out‐patients with hypertensive urgency or hypertensive emergency for the presence of mutations in the carboxy terminus of these genes. Furthermore, serum potassium concentrations were determined in all 90 patients, and serum aldosterone levels and plasma renin activity were measured in a subset of 34 patients.

Results

Among 71 patients with hypertensive urgency (78.9%) and 19 patients with hypertensive emergency (21.1%) not one individual showed a mutation in genomic DNA extending from codon 532 to codon 637 of hβENaC and from codon 525 to codon 651 of hγENaC. Twelve of 90 patients showed mild hypokalaemia (13.3%), 16 of 34 patients had a plasma renin activity below the lower normal range (47.1%) and one of 34 patients had a low serum aldosterone concentration (2.9%).

Conclusions

The present study clearly demonstrates the absence of mutations in the carboxy terminus of the hβENaC and hγENaC gene of hENaC in an Austrian cohort of 90 patients suffering from hypertensive crisis.
Leptin levels in smokers and long‐term users of nicotine gum
Authors: Eliasson B. , Smith U.
Published: March 2003

Background

The aim of this study was to examine the effects of cigarette smoking and other forms of long‐term nicotine consumption on circulating leptin levels as well as the relationship between leptin levels and insulin sensitivity, measured with the euglycaemic hyperinsulinaemic clamp, in healthy middle‐aged men.

Study design

Samples from 73 subjects were analysed: 23 non‐smokers, 31 smokers and 19 long‐term nicotine gum chewers (NGCs) with similar ranges of age, body mass index (BMI) and per cent body fat.

Results

Leptin levels were higher in NGCs and smokers than in the non‐smoking matched control subjects. Smoking cessation for 8 weeks further increased the leptin levels, probably due to the concomitant increase in body fat (mean ± SD, 2.2 ± 1.8 kg). Acute administration of one dose of nicotine nasal spray or smoking one cigarette did not significantly change the circulating leptin levels during the following 60 min. Plasma leptin concentrations were positively correlated with the proportion of body fat and negatively correlated with the degree of insulin sensitivity in each of the three subject groups. In a stepwise multiple linear regression analysis, plasma leptin concentrations were significantly correlated with the proportion of body fat, degree of insulin sensitivity and smoking status.

Conclusion

These data show that long‐term use of nicotine is associated with elevated circulating leptin levels. The increased leptin levels may be an important reason for the lower body weight in smokers. The results of this study also support the view that leptin is directly or indirectly related to insulin sensitivity in men.
Cell death by overload of the elastin–laminin receptor on human activated lymphocytes: protection by lactose and melibiose
Authors: Péterszegi G. , Texier S. , Robert L.
Published: March 2003

Background

Activated human lymphocytes were shown to express the elastin–laminin receptor in vitro and also in vivo in atherosclerotic plaques. In the presence of the agonist, elastin peptides, this receptor was shown to mediate an increased cell proliferation and an increased synthesis and excretion of an elastase‐type serine endopeptidase. In this study, we investigated the variation of the above reaction as a function of agonist concentration.

Materials and methods

Human lymphocytes were obtained by tonsillectomy and cultured in the presence of phytohaemagglutinin and elastin peptides. Cell viability was evaluated by vital dye exclusion. Elastase and cathepsin G activities were determined in culture supernates and cell lysates using synthetic substrates. Apoptotic cells were identified by the TUNEL method and by electron microscopy.

Results

At increasing concentrations of elastin peptides, a dose‐dependent increase in cell death was observed. Up to 100 μg mL−1 elastin peptides and an increasing fraction of lymphocytes were found permeable to trypan blue, and a large proportion was in apoptosis. Elastin peptide‐induced cell death was inhibited by 1 μg mL−1 lactose and melibiose.

Conclusion

We describe here cell death of human activated lymphocytes expressing the elastin–laminin receptor in the presence of increasing concentrations of elastin peptides, agonists of the receptor. The mechanism of cell death appears to be related to the triggering of the release of elastase and free radicals mediated by the elastin–laminin receptor. Antagonists of this receptor, lactose and melibiose, protected the lymphocytes from the receptor‐mediated cell death.
Effects of intensified lifestyle modification on the need for further revascularization after coronary angioplasty
Authors: Wallner  , Watzinger  , Lindschinger  , Smolle  , Toplak  , Eber  , Dittrich  , Elmadfa  , Klein  , Krejs  , Wascher
Published: March 2003

Background

In patients with coronary artery disease (CAD), a rate of restenosis as high as 50% is observed after percutaneous transluminal coronary angioplasty (PTCA). Frequently, this results in further revascularization procedures. Lifestyle intervention has been shown to slow the progression of CAD and to reduce cardiovascular events after myocardial infarction. However, no information exists whether such treatment influences the rate of restenosis in patients with CAD. The present study was performed to investigate the effects of an intensified lifestyle intervention on the need for further revascularization procedures in patients with established CAD after successful PTCA.

Design

A total of 60 patients were included and randomized to either conventional treatment by cardiologists and general practitioners or additional intensified lifestyle intervention in a diabetes and metabolism outpatient clinic for 12 months. The mean observation time after successful PTCA was 26 months. The primary outcome variable was the need for further revascularization procedures because of clinical restenosis. Secondary outcome variables were lifestyle‐related measures.

Results

Intervention resulted in a reduction in body weight and blood pressure, and in increased physical activity. Furthermore, nutritional habits were changed towards less fat intake, and body composition changed towards a higher proportion of fat‐free mass. The need for further revascularization procedures was reduced from a total of 14 out of 32 in the conventionally treated group to 3 out of 28 in the intervention group. This resulted in an event‐free survival probability of 0.89 in the intervention group and 0.57 in the control group (P = 0.0055, log rank) with a resulting relative risk of 0.26 (95% CI 0.09–0.74).

Conclusion

In conclusion, our data strongly suggest that intensified lifestyle modification is able to reduce the need for further revascularization procedures after PTCA in patients with CAD.
Long‐term stability of human immunodeficiency virus viral load and infectivity in whole blood
Authors: Vandamme  , Van Laethem  , Schmit  , Van Wijngaerden  , Reynders  , Debyser  , Witvrouw  , Van Ranst  , De Clercq  , Desmyter
Published: March 2003

Background

We intended to evaluate the stability of human immunodeficiency virus (HIV) type 1 virions in whole blood and in culture medium.

Materials and method

EDTA whole‐blood samples taken from 12 patients were left at room temperature for up to 7 days, and aliquots of a laboratory virus stock spiked in EDTA, in heparinized or in citrated whole blood, with or without the addition of Triton X‐100, or spiked in culture medium were left at room temperature for up to 120 days before plasma was separated and frozen at −80 °C. Viral load was measured for all frozen plasma samples using different viral load assays. p24 antigen and infectivity were also measured in the spiked samples.

Results

The patient whole‐blood samples did not show any decrease in viral load during this 7‐day period. The spiked samples decayed by not more than 1 log after 120 days (about 4 months), with the fastest decay in medium. Virus infectivity decayed very slowly from 20 000 units mL−1 to undetectable amounts after 56 days.

Conclusions

These results indicate that HIV‐1 virions in whole blood possess a long‐term stability in terms of viral load, p24 antigen level and infectivity, which is not sufficiently recognized by laboratory and health care workers.
New strategies in anti‐vascular cancer therapy
Authors: Bloemendal  , Logtenberg  , Voest
Published: March 2003

Angiogenesis is a critical step in the progression of tumours from dormancy to a clinical relevant cancer. Inhibition of this process is one of the most promising new anti‐cancer strategies. To develop new drugs that interfere with the cascade of events required for the formation of new blood vessels, insight into this process is essential. Here, we discuss the molecular basis of angiogenesis and the concepts of vascular targeting. Furthermore new strategies will be discussed to discover surface markers on endothelial cells that confer sufficient specificity for targeted intervention in the tumour vasculature.
Persistent symptoms in former UNTAC soldiers are not associated with shifted cytokine balance
Authors: Soetekouw  , De Vries  , Preijers  , Van Crevel  , Bleijenberg  , Van Der Meer
Published: March 2003

Background

The pathogenesis of post‐combat syndromes, such as Gulf War syndrome, is poorly understood. Recently, it has been postulated that the symptoms of veterans with such syndromes are due to a disturbed cytokine balance shifted towards a T‐helper (Th) 2 profile. We investigated this hypothesis in 21 symptomatic former UNTAC soldiers and compared their results with those obtained in 21 healthy former UNTAC soldiers matched for age, sex and military force.

Design

The numbers of intracellular interleukin 4 (IL‐4) and interferon gamma‐ (IFN‐γ) producing CD4+ and CD8+ T lymphocytes (CD3+) were determined after in vitro stimulation with phorbol myristate acetate and calcium ionophore in the presence of brefeldin to block secretion of induced cytokines. Circulating concentrations and lipopolysaccharide‐ (LPS) or phytohaemagglutinin‐ (PHA) stimulated whole‐blood production of the proinflammatory cytokines IL‐1β, IL‐1ra, tumour necrosis factor alpha (TNF‐α) and IL‐10 and IFN‐γ were measured.

Results

The numbers of CD4+ and CD8+ T lymphocytes positive for IL‐4 or IFN‐γ production were not significantly different in patients and control subjects. After stimulation with LPS or PHA, the in vivo circulating concentration and concentration of IL‐10 and IFN‐γ were also similar.

Conclusions

The present study demonstrates that there is no shift in cytokine balance towards a Th2 profile in former UNTAC soldiers with symptoms similar to those of the Gulf War syndrome.
High serum laminin concentrations in patients with Candida sepsis
Authors: Presterl  , Lassnigg  , Mueller‐Uri  , Wenisch  , El‐Menyawi  , Graninger
Published: March 2003

Background

Laminin, a major component of the basement membrane, plays a critical role in normal cell adhesion and also during tissue invasion of pathogenic microorganisms.

Materials and methods

Serum laminin concentrations were determined in 19 patients with Candida albicans sepsis, in 13 patients with bacterial sepsis and in 20 noninfectious controls.

Results

Serum laminin concentrations of both, patients with candidal and bacterial sepsis, were significantly elevated compared to the controls (486 ng mL−1 [155–924], median [range]; P < 0.01). Laminin concentrations were significantly higher in patients with Candida sepsis than in patients with bacterial sepsis on day 1 (2565 ng mL−1 [659–6064] vs. 994 ng mL−1 [386–2064]; P < 0.01), day 7 (1594 ng mL−1 [607–4611] vs. 684 ng mL−1 [284–1920]; P < 0.05) and day 14 (1444 ng mL−1 [202–2131] vs. 386 ng mL−1 [180–1658]; P < 0.05).

Conclusions

Laminin serum concentrations might be useful to differentiate nonbacterial, bacterial and fungal etiology.
Intrapleural administration of tumour necrosis factor‐alpha (TNFα) in patients with mesothelioma: cytokine patterns and acute‐phase protein response
Authors: Stam  , Swaak  , Kruit  , Stoter  , Eggermont
Published: March 2003

Background

Tumour necrosis factor‐alpha (TNFα) has been found to be very effective in the isolated limb perfusion setting for advanced extremity tumours. In a phase I study of intrapleural administration of TNFα 5 patients were followed for inflammatory response patterns.

Patients and methods

Malignant mesothelioma patients were treated with repeated intrapleural administration of 0.1–0.2 mg recombinant TNFα. Samples of serum and pleural fluid were taken at different time‐points before and after TNFα‐administration. Levels of TNFα, interleukin‐6 (IL‐6), interleukin‐8 (IL‐8), C‐reactive protein (CRP) and secretory phospholipase A2 (sPLA2) were measured using enzyme‐linked immunosorbent assays (ELISAs). Alpha 1‐acid glycoprotein (α1‐AG) was measured by nephelometry.

Results

In pleural fluid TNFα and IL‐8 reached peak levels, up to 50–700 ng mL−1 and 6–60 ng mL−1, respectively, 24 h after administration of TNFα. IL‐6 (peak levels up to 250 ng mL−1) and sPLA2 peaked after 48 h. A slower and less dramatic pattern was observed for the levels of CRP and α1‐AG. In serum no detectable levels of TNFα and no IL‐8 were observed, whereas serum levels of IL‐6, sPLA2 and CRP showed a clear increase after intrapleural administration of TNFα. Cytokines and acute‐phase proteins showed the same pattern during subsequent cycles even up to 12 cycles. Tumour regression was not observed.

Conclusions

In the setting of a phase I study of repetitive intrapleural administration of TNFα in mesothelioma patients, we studied the characteristics of the inflammatory response. Intrapleural administration was followed by a clear inflammatory response locoregionally. In spite of TNFα peak levels as high as 700 ng mL−1 systemic levels were never detectable. The secondary cytokine response led to very high intrapleural IL‐6 and IL‐8 levels. Systemically IL‐8 levels were never detectable whereas high IL‐6 levels were induced systemically initially, with a decreased response to each intrapleural TNFα administration over time. The acute‐phase response in contrast remained remarkably constant throughout the course of repeated intrapleural administrations of TNFα. Intrapleural administration of TNFα is well tolerated but associated with inconsistent and rather moderate impact on production of pleural fluid. This can be achieved by other simpler and cheaper treatment, thus we see no justification for further studies.
The 16p11 breakpoint in myxoid liposarcomas might affect the expression of the LRP gene on 16p11.2 encoding the multidrug resistance associated major vault protein
Authors: Plaat  , Molenaar  , Sagrudny  , Bohle  , Mastik  , Hoekstra  , Van der Graaf  , Hollema  , Van Den Berg
Published: March 2003

Background

Chromosome breakage could influence the expression of genes. This has been noticed in specific cases of acute myeloid leukaemia, where the 16p13 breakpoint affects the expression of the multidrug resistance related protein (MRP). Myxoid liposarcomas (LPS) are characterized by the t(12; 16)(q13; p11), which leads to the formation of a FUS‐CHOP fusion transcript. This study investigates the relationship between the cytogenetically detected breakpoint 16p11 in myxoid LPS, the presence of the FUS‐CHOP fusion transcript in nonmyxoid LPS and the expression of the lung resistance major vault protein (LRP) gene on 16p11.2.

Materials and methods

Of 16 cases with a diagnosis of a (possible) liposarcoma with an abnormal karyotype, fresh frozen tumour material was available for immunohistological detection of LRP. Cases without a cytogenetically detected t(12; 16)(q13; p11), were analyzed for the presence of a FUS‐CHOP fusion transcript by RT‐PCR.

Results

In all 9 myxoid LPS a t(12; 16)(q13; p11) was found and LRP expression was absent or low. In none of the remaining 7 cases was a FUS‐CHOP fusion transcript found, and four tumours were LRP positive (P = 0.02). LRP expression in myxoid LPS (mean: 1.3%) was lower (P = 0.07) than in the nonmyxoid tumours (mean: 35.7%).

Conclusions

These observations indicate a relation between the t(12; 16)(q13; p11), leading to a FUS‐CHOP fusion transcript in myxoid LPS, and the low or absent expression of the LRP‐gene located on 16p11.2.
Susceptibility to neuromediated syncope after acute myocardial infarction
Authors: Wa¸sek  , Kułakowski  , Czepiel  , Kłosiewicz‐Wa¸sek  , Budaj  , Soszyńska  , Maciejewski  , Stec  , Ceremużyński
Published: March 2003

Background

Syncope after acute myocardial infarction (AMI) is a common clinical problem. It may be hypothesised that remodelling and neurohormonal changes following AMI may predispose to neuromediated syncope.

Design

To address this issue we prospectively evaluated the incidence of positive results of head‐up tilt‐table testing in 40 patients following AMI and 40 age and sex matched controls without a history of syncope. The mechanisms of tilt‐induced changes in autonomic tone were assessed using spectral analysis of heart rate variability. The patients were followed‐up for one year.

Results

Positive results of tilt‐test occurred in 4 (10%) controls and 13 (33%) AMI patients (P = 0.01). No significant differences in sympathovagal interaction (assessed by a low frequency/high frequency ratio) were detected between the groups before tilting (2.9 ± 1.9 vs. 3.1 ± 2.2; NS). However, dynamic changes of this parameter differed significantly during the first 5 symptomless minutes of the active phase of tilt‐test. The ratio increased in the majority of controls (87%) and decreased in the majority of patients (62%) (P < 0.0001). During one year follow‐up, syncope or presyncope occurred in 10 (25%) AMI patients but did not occur in any control subject (P < 0.001). The sensitivity, specificity and predictive accuracy of an early tilt‐test after AMI for the prediction of syncope or presyncope was 70%, 80% and 78%, respectively.

Conclusion

Patients after AMI are prone to neuromediated reactions. Sympathetic withdrawal seems to be the most likely mechanism of syncope. The role of tilt testing for identification of patients susceptible to syncope or presyncope after AMI needs further investigation.
Microvascular angina (cardiological syndrome X) per se is not associated with hyperinsulinaemia or insulin resistance
Authors: Cavallo Perin  , Pacini  , Giunti  , Comune  , Conte  , Cassader  , Pagano
Published: March 2003

Background

Microvascular angina has been found to be associated with insulin resistance. However, many factors known to affect insulin sensitivity were not excluded in patient selection. We aimed to evaluate whether microvascular angina is per se associated with insulin resistance.

Materials and methods

We performed a Frequently Sampled Intravenous Glucose Tolerance Test (0.33 g kg−1 b.w.) in 10 normal weight and normotensive patients with microvascular angina, with normal glucose tolerance and normal plasma lipids. Ten healthy subjects, comparable for age, sex, body mass index, blood pressure and plasma lipids, were used as control group.

Results

Fasting serum glucose (4.49 ± 0.2 SEM vs. 4.52 ± 0.13 mmol L−1, P = 0.9), insulin (39.46 ± 3.68 SEM vs. 47.12 ± 4.6 pmol L−1, P = 0.21) and C‐peptide (0.56 ± 0.05 SEM vs. 0.53 ± 0.05 nmol L−1, P = 0.68) values, as well as estimated parameters of insulin secretion and hepatic insulin extraction were similar in the two groups. Insulin sensitivity values (median, range) were also similar in the patients and control subjects (5.76 (3.39–12.30) vs. 7.54 (3.68–13.89. 10−4. min−1/(μU/mL), P = 0.97).

Conclusion

Microvascular angina per se is not associated with hyperinsulinaemia or insulin resistance when other confounding factors are excluded in patient selection.
Polymorphisms in the vitamin D receptor gene and bone mass, bone turnover and osteoporotic fractures
Authors: Langdahl  , Gravholt  , Brixen  , Eriksen
Published: March 2003

Background

Vitamin D is essential for normal bone metabolism. Polymorphisms in exon 2, intron 8 and exon 9 of the vitamin D receptor (VDR) gene have previously been found to be associated with bone mass and bone turnover.

Materials and methods

We examined the effect of these polymorphisms, separately and in combination, on bone mineral density (BMD), bone turnover, and the prevalence of osteoporotic fractures in 192 osteoporotic patients and 207 normal controls. The four polymorphisms were determined by RFLP using Fok I (T2‐C), Bsm I (intron 8), Apa I (intron 8) and Taq I (T1055‐C) after PCR.

Results

We did not find any association between the Fok I polymorphism and bone mass, bone turnover or prevalence of osteoporotic fractures. We found that BB + Bb‐genotypes were more frequent in patients with osteoporotic fractures (χ2 = 3.50, P = 0.06). Furthermore, BMD of the intertrochanteric region (P < 0.0001,
anova) as well as the total hip (P < 0.01,
anova) were higher in individuals with the bb‐genotype. The Apa I and the Taq I polymorphisms were not distributed differently among osteoporotic patients and normal controls. Apa I was not associated with differences in BMD. BMD of the intertrochanteric region was higher in individuals with the TT‐genotype compared with individuals with the Tt‐ or tt‐genotypes (P < 0.01,
anova), while no differences could be demonstrated in BMD of the lumbar spine, femoral neck, trochanter or Wards triangle. Combining the genotypes generally reflected the differences caused by the Bsm I polymorphism.

Conclusion

We have found that the B‐allele of the Bsm I polymorphism in the 3′ untranslated region of the VDR was associated with low BMD at the hip, and tended to be associated with osteoporotic fractures. The translation initiation polymorphism in the VDR does not affect BMD and is not associated with osteoporotic fractures in men or women.