bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of diagnostic laparoscopy on the management of gastric cancer: prospective study of 120 consecutive patients with primary gastric adenocarcinoma
Authors: Lehnert T , Rudek B , Kienle P , Buhl K , Herfarth C 
Published: March 2003

Abstract

Background
Peritoneal seeding or liver metastases found at laparotomy usually preclude curative treatment in patients with gastric adenocarcinoma. Such exploratory laparotomies may be avoided by diagnostic laparoscopy. However, routine diagnostic laparoscopy does not benefit those patients who proceed to laparotomy after negative laparoscopy. The aim of this study was to evaluate prospectively the selective use of laparoscopy in uncertain situations.

Methods
One hundred and twenty consecutive patients with primary gastric adenocarcinoma were studied prospectively. Diagnostic laparoscopy was performed in patients with clinical T4 tumours or suspected metastases, unless laparotomy was required for symptomatic disease.

Results
Ninety-six of 120 patients were selected for immediate laparotomy with curative intent (n = 81) or for palliation (n = 15). In two of the 81 patients gastrectomy was abandoned because of unexpected peritoneal carcinomatosis. Fifteen patients underwent diagnostic laparoscopy, which identified intra-abdominal metastases in six; the other nine patients proceeded to laparotomy, which revealed peritoneal metastases not detected at laparoscopy in four patients. The remaining nine patients had overt metastases and were referred for systemic chemotherapy without abdominal exploration.

Conclusion
Diagnostic laparoscopy in selected patients effectively limits the number of unnecessary invasive staging procedures. Routine use of diagnostic laparoscopy in all patients with gastric adenocarcinoma is not warranted.
Butyrate affects differentiation, maturation and function of human monocyte-derived dendritic cells and macrophages
Authors: MILLARD A L , MERTES P M , ITTELET D , VILLARD F , JEANNESSON P , BERNARD J 
Published: March 2003

SummaryWe studied the in vitro effects of butyric acid on differentiation, maturation and function of dendritic cells (DC) and macrophages (MΦ) generated from human monocytes. A non-toxic dose of butyrate was shown to alter the phenotypic differentiation process of DC as assessed by a persistence of CD14, and a decreased CD54, CD86 and HLA class II expression. The more immature differentiation stage of treated cells was confirmed further by their increased phagocytic capability, their altered capacity to produce IL-10 and IL-12, and their weak allostimulatory abilities. Butyrate also altered DC terminal maturation, regardless of the maturation inducer, as demonstrated by a strong down-regulation of CD83, a decreased expression of CD40, CD86 and HLA class II. Similarly, butyrate altered MΦ differentiation, down-regulating the expression of the restricted membrane antigens and reducing the phagocytic capacity of treated cells. To investigate further the mechanism by which butyrate hampers the monocyte dual differentiation pathway, we studied the effects of 1,25(OH)2D3 alone or in combination with butyrate on the phenotypic features of DC. Unlike 1,25(OH)2D3, butyrate inhibited DC ­differentiation without redirecting it towards MΦ. Combined treatment gave rise to a new cell subset (CD14high, CD86 and HLA-DRlow) phenotypically distinct from monocytes. These results reveal an alternative mechanism of inhibition of DC and MΦ differentiation. Altogether, our data demonstrate a novel immune suppression property of butyrate that may modulate both inflammatory and immune responses and support further the interest for butyrate and its derivatives as new immunotherapeutic agents.
Effects of deoxycholate on human colon cancer cells: apoptosis or proliferation
Authors: Milovic V. , Teller I. C. , Faust D. , Caspary W. F. , Stein J. 
Published: March 2003

Abstract Background  Deoxycholic acid has long been attributed as a tumour promoter in the colon. It exerts its growth‐related actions in a phorbol ester‐like manner, by stimulating protein kinase C. The aim of this study was to investigate the effect of deoxycholic acid on proliferation and apoptosis in the colon, by exposing colon cancer cells to it in increasing concentrations.Methods  Human colon cancer cells (Caco‐2 and HT‐29) were treated with deoxycholate or its two structural isomers, 3‐beta‐12‐alpha‐dihydroxy‐5‐beta‐cholan‐24‐oic acid and 3‐alpha‐12‐beta‐dihydroxy‐5‐beta‐cholan‐24‐oic acid. Proliferation was evaluated by cell counting, and apoptosis by estimating percentage cell survival and assessment of nuclear morphology.Results  Within the concentration range of up to 20 µM, deoxycholate stimulated growth of both human colon cancer cell lines. Its growth‐promoting effect was abolished after inhibition of protein kinase C. At concentrations above 100 µM, deoxycholate induced apoptosis in both cell lines. Epimers of deoxycholate were significantly less potent in stimulating growth.Conclusion  Low‐dose deoxycholate stimulates colon cancer cell proliferation while > 100 µmol L−1 of this secondary bile acid induces apoptosis in colon cancer cells. Deoxycholate might promote the likelihood of malignant transformation by increasing epithelial cell turnover in the colon.
A new insight into aspirin‐induced asthma
Authors: Jawien J. 
Published: March 2003

AbstractIn about 10% of adult patients with asthma, aspirin and other nonsteroidal anti‐inflammatory drugs precipitate attacks of dyspnoea. Accumulated evidence shows that these reactions are due to the interference of aspirin‐like drugs with arachidonic acid metabolism in the lungs of the sensitive patients: inhibition of cyclooxygenase is accompanied by overproduction of cysteinyl leukotrienes. The mechanisms of these reactions and the characteristic course of aspirin‐induced asthma and its management are discussed.
In vitro determination of active bile acid absorption in small biopsy specimens obtained endoscopically or surgically from the human intestine
Authors: Ung K‐A. , Olofsson G. , Fae A. , Kilander A. , Ohlsson C. , Jonsson O. 
Published: March 2003

Abstract Background In the construction of a Kock reservoir for continent urinary diversion, 70 cm of the distal ileum are used. Impaired absorption of bile acids in these patients might cause diarrhoea. Data on the absorption of bile acids in different parts of the human intestine are limited.Methods Biopsies were taken during endoscopy from the duodenum, the terminal ileum or the right colon, and during surgery 10, 50, 100 and 150 cm proximally to the ileo‐caecal valve using standard endoscopy biopsy forceps. The biopsy specimens were incubated in vitro with radio‐labelled taurocholic acid at 37 °C for 22 or 45 min The radioactivity was determined using the liquid scintillation technique.Results A linear increase in the uptake was observed, with increased concentrations of taurocholic acid between 100 and 500 µm in all specimens tested, that represented passive uptake or unspecific binding. The active uptake could be calculated from the intercept of the line representing passive uptake with the ordinate. The active uptake in the terminal ileum was 3–4 times greater than 100 cm proximal to the valve.Conclusions The active absorption of bile acids in humans can be determined in small biopsy specimens taken using standard biopsy forceps during endoscopy or surgery. This method is suitable for clinical studies of bile acid absorption. Active uptake of bile acids not only takes place in the very distal part of the ileum but also to a considerable degree 100 cm proximally to the ileo‐colonic valve. This should be taken into account when selecting the ileal segment for continent urinary diversion.
The effect of anti‐allergic mattress encasings on house dust mite‐induced early‐ and late‐airway reactions in asthmatic patients. A double‐blind, placebo‐controlled study
Authors: Rijssenbeek‐Nouwens L. H. M. , Oosting A. J. , De Monchy J. G. R. , Bregman I. , Postma D. S. , De Bruin‐Weller M. S. 
Published: March 2003

Background Anti‐allergic mattress encasing may provide clinical benefit in asthmatic patients. However, the effect of mattress encasings on allergen‐specific parameters, such as bronchial reactions to house dust mite (HDM) challenge, is not clear.Objective To investigate the effect of anti‐allergic mattress encasings on allergen sensitivity in patients with moderate to severe asthma.Methods Twenty‐seven patients with asthma and HDM allergy were studied in a double‐blind, placebo‐controlled study. Concentrations of Dermatophagoides pteronyssinus (Der p 1) were measured in mattress dust before and after 1 year of treatment; bronchial histamine challenge, bronchial challenge with HDM and intradermal skin challenges with HDM were performed. The number of eosinophils in peripheral blood was assessed.Results In the active group, but not in the placebo group, there was a significant reduction in Der p 1 concentration in the dust collected from the mattresses after 1 year of treatment compared to before. There was a significant difference between the groups with respect to HDM‐induced early‐reaction (ER) in the airways and the number of blood eosinophils, which reflected an increase in ER and eosinophils in the placebo group without significant change in the active group. No significant improvement in PC20 histamine, late‐reaction (LR) and skin tests was found in either groups.Conclusion Our data suggest that encasings protect against a further increase in allergen sensitivity in asthmatic patients, so their use should be recommended.
Ecological impact of large herbivores on the woody vegetation at selected watering points on the eastern basaltic soils in the Kruger National Park
Authors: Brits J. , Van Rooyen M. W. , Van Rooyen N. 
Published: March 2003

AbstractA lack of quantitative data on the impact of large herbivores on woody vegetation around watering points in the Kruger National Park gave rise to an in depth study. This paper reports on trends found at two artificial watering points on the basaltic soils in the Satara Land System. As a result of the almost complete lack of woody individuals in the immediate vicinity of the watering points, this area could be described as a ‘sacrifice area’. Shrub density increased with distance from the watering point, with the impact of large herbivores on shrub density extending up to 2.8 km. The practice of providing artificial water in troughs at windmills in the Kruger National Park causes the formation of a multiple ‘piosphere’ effect, with the existence of a zone of high utilization in woody vegetation extending far beyond the sacrifice area.
Wing wear, aerodynamics and flight energetics in bumblebees (Bombus terrestris): an experimental study
Authors: Hedenström A. , Ellington C. P. , Wolf T. J. 
Published: March 2003

Summary

Previous work has shown that wing wear increases mortality rate in bumblebees. Two proximate explanations have been suggested to account for this: increased energy flight costs and increased predation risk due to reduced manoeuvrability.
Wing wear was mimicked by experimentally clipping the forewing distal trailing edge, causing a 10% wing area reduction. Experimental and sham control bumblebees were induced to hover in a flight respirometry chamber for measuring metabolic rate of hovering. Simultaneous video and sound recordings were taken for wingbeat kinematic data required for an aerodynamic analysis.
In the experimental group with reduced wing area we measured increased wingbeat frequency, lift coefficient and induced power, but a reduced profile power. The mechanical power output, assuming perfect elastic storage in the flight system, remained largely unchanged after the wing‐trimming treatment.
Metabolic flight costs (CO2 production rate) did not increase significantly in the reduced wing area group, which is in line with the aerodynamic power output.
Our results indicate that an increase of flight cost due to wing wear is not a likely explanation for increased mortality rate in bumblebees. Wing wear may, however, affect escape performance from predators.
Interspecific defoliation responses of trees depend on sites of winter nitrogen storage
Authors: Millard P. , Hester A. , Wendler R. , Baillie G. 
Published: March 2003

Summary

To determine if the response of trees to herbivory is related to their ability to store nitrogen, saplings of Pinus sylvestris L., Betula pendula Roth. and Sorbus aucuparia L. were clipped, either when dormant or at spring bud burst, to remove half the previous year’s shoot growth. The impact of clipping on N remobilization and uptake was quantified in relation to their growth responses.
Pinus sylvestris stored N during the winter in needles grown the previous summer, whereas B. pendula and S. aucuparia used their woody roots and older stems. Therefore, N remobilization was unaffected by clipping the deciduous species, but was reduced by half in the evergreen.
For both P. sylvestris and B. pendula, root uptake contributed N for leaf growth immediately after bud burst, concurrently with remobilization. Sorbus aucuparia had remobilized half the N from storage before any N was taken up by the roots.
Pinus sylvestris, which has a fixed pattern of growth, produced a lower total needle mass when clipped, but individual needles were heavier. Nitrogen uptake during summer was reduced by 26 and 44% for winter‐ and spring‐clipped saplings, respectively. Both deciduous species showed compensatory leaf growth such that, by the end of the summer, leaf mass (and B. pendula leaf area) were unaffected by clipping. Nitrogen uptake by both deciduous species was unaffected by clipping.
We conclude that the site of N storage during winter is a crucial factor in determining the response of a sapling to herbivory, as interactions with the growth patterns of the three species can lead to different responses to damage. We suggest that for evergreen trees, the production of antiherbivory compounds serves primarily to protect N stored in their foliage, rather than the leaves themselves.
Asymmetric competition between plant species
Authors: Freckleton R. P. , Watkinson A. R. 
Published: March 2003

Summary

Asymmetric competition is an unequal division of resources amongst competing plants. Thus, competition may be asymmetric in the sense that some individuals remove a disproportionately large amount of resource. Alternatively, competition may be asymmetric in that one species removes a disproportionately large amount of resource. The mechanisms determining the two forms of asymmetry may be similar, for example through initial size advantage or over‐topping.
We explore the consequences of these two forms of asymmetry for competition models that predict mean performance as a function of the density of interacting species. We do so using neighbourhood models that explicitly consider the allocation of resources to individuals within an interacting mixture.
Asymmetric individual competition is modelled by assuming that individuals are formed into a competitive hierarchy such that individuals at the top of the hierarchy are able to remove more resources than those at the bottom. Mean performance declines exponentially, moving from top to bottom of the hierarchy. Asymmetric species‐level competition is modelled by assuming that one species occupies all of the upper positions in the competitive hierarchy and hence dominates the resource.
When competition is asymmetric at the species level, yield–density responses follow an exponential decline. Otherwise, arithmetic mean performance follows a classic hyperbolic response.
Using this approach, we explore the asymmetry of competition between wheat and three species of weeds.
Variation of fuelling rates among sites, days and individuals in migrating passerine birds
Authors: Schaub M. , Jenni L. 
Published: March 2003

Summary The seasonal migration of birds is divided into alternating phases of stopover and flight. The fuel deposition rate at stopover sites is the crucial factor determining overall speed of migration and its success. Therefore, field data about the variation in fuel deposition rates at different levels (among sites, seasons, days, individuals) are essential to explain the observed behavioural reactions to environmental variability and migration strategies. Fuel deposition rates of four species of passerine migrant birds captured at 14 stopover sites from northern Europe to sub‐Saharan Africa during autumn and spring were analysed. Plasma concentrations of triglycerides and β‐hydroxy‐butyrate were used to estimate relative fuel deposition rates (named fattening index). The largest variation in fattening indices was between sites which was only weakly explained by geographical position relative to ecological barriers and did not differ between spring and autumn. Therefore it is expected that the selection of appropriate stopover sites is of paramount importance for the success of migration. Variation in fattening index between days within sites was comparatively small with no obvious seasonal trend over the restricted period of mid‐migration and with no correlation between subsequent days. However, only samples during good weather days were examined and the full range of this variation could not be estimated. Air temperature and duration of rainfall could explain part of this variation, probably because invertebrate availability is higher during warm and dry weather. The variation of fattening rates between birds on the same day and site was low, and could partially be explained by body mass. Heavy birds had higher fattening rates than light birds. From this analysis, it appears to be difficult for migrating birds to predict the fattening rate of the next stopover site, but relatively easy to assess the fattening rate of the current site in a short time. This may result in larger departure fat loads than would be necessary to reach the next stopover site.
Carotenoid access and intraspecific variation in plumage pigmentation in male American Goldfinches (Carduelis tristis) and Northern Cardinals (Cardinalis cardinalis)
Authors: McGRAW K. J. , HILL G. E. 
Published: March 2003

Summary

Behavioural ecologists have shown much interest recently in the factors that promote variation in carotenoid‐based colour displays. Because vertebrates cannot synthesize the pigments needed to attain this form of bright coloration, most research has focused on the effect of dietary access to pigments on carotenoid ornamentation.
However, few studies have considered experimentally how the availability of carotenoid pigments in the diet influences variability in the expression of carotenoid‐based coloration.
Dietary access to carotenoids was manipulated in captive groups of male American Goldfinches (Carduelis tristis L.) and Northern Cardinals (Cardinalis cardinalis L.) to assess the role of pigment acquisition in shaping intraspecific variation in carotenoid‐based plumage pigmentation.
Substantial variation was detected in the plumage displays of captive male goldfinches and cardinals within a diet treatment, such that birds with unlimited access to the same diet type displayed carotenoid‐based plumage variation that did not differ significantly from that typical of wild males from each species. Additionally, the natural plumage brightness that male goldfinches displayed at capture predicted the degree to which they grew colourful plumage under controlled conditions in our experiments.
These results suggest that carotenoid‐based plumage variation in male goldfinches and cardinals is less sensitive to pigment availability in the diet than colour variation observed in other studied taxa. Differences in ornamental coloration among males from these two passerine species may instead reflect their ability to utilize ingested pigments physiologically.
Environmentally induced variation in floral traits affects the mating system in Datura wrightii
Authors: Elle E. , Hare J. D. 
Published: March 2003

Summary

If pollination is unpredictable, selection may favour the production of selfed seeds in the absence of pollen vectors, even in plant species with obvious adaptations for outcrossing. Pollination may be less predictable for plants growing in certain environments if environmental factors affect the floral phenotype. Through effects on flower morphology and the floral display, the environment may affect the outcrossing rate.
We manipulated two environmental factors, water availability and exposure to insect herbivores, in a common‐garden experiment using a perennial herb, Datura wrightii. We measured herkogamy (the separation of anthers and stigmas within flowers), total flower length, and flower number, and used a single‐gene trichome dimorphism as a marker to determine per‐plant outcrossing rates.
The large amount of variation in herkogamy was affected by trichome type, irrigation and herbivory. In addition, watered plants had longer corollas, and plants attacked by herbivores had fewer open flowers. Thus environmental factors affect floral phenotype.
However, irrigation and herbivory did not directly affect outcrossing rate. There were indirect effects of these treatments on outcrossing because plants with increased herkogamy and fewer open flowers had higher outcrossing rates.
A greenhouse experiment showed that autonomous selfing is more likely when herkogamy is reduced, and can occur both as the flower opens and when the corolla is shed.
These experiments are among the first to show that within‐population variation in the mating system can be due to environmentally induced variation in floral traits.
A population pharmacokinetic analysis of sildenafil citrate in patients with erectile dysfunction
Authors: Milligan Peter A. , Marshall Scott F. , Karlsson Mats O. 
Published: March 2003

Aims  To analyse the pharmacokinetics of sildenafil citrate in patients with erectile dysfunction in order to characterize covariate relationships and assist in the development of rational dosage strategies.Methods  A population pharmacokinetic sampling strategy was incorporated into five phase III clinical study protocols. Overall, 2077 patients, 1335 of whom received sildenafil, were asked to take an additional dose of study drug before their scheduled clinic visits on four or five occasions throughout the study duration. A single plasma sample was obtained at random times postdose (range 1–7 h), and a total of 4582 samples were assayed (average 3.4 samples per individual).Results  For the population average patient (age 58 years; aspartate transaminase [AST], 24 IU l−1; weight, 87 kg; not receiving CYP3A4 potential inhibitors), typical values for sildenafil (mean±SE) were 58.5±1.4 l h−1 for apparent clearance (CL/F), 310±6.92 l for volume of distribution (V/F), and 2.6±0.176 h−1 for first‐order absorption constant (ka). The value for ka is associated with meal consumption within 2 h predose, at all other times ka was equivalent to an instantaneous bolus administration. The interindividual variabilities were 29% for CL/F, 20% for V/F, and 210% for ka. Over a dose range of 25–100 mg sildenafil, the pharmacokinetics exhibited dose proportionality. There was evidence of nonproportionality (40% increase on average) in relative bioavailability with respect to the 200‐mg dose (P<0.001) relative to the other doses. Age, AST concentration, and co‐administration with CYP3A4 potential inhibitors significantly influenced CL/F of sildenafil (P<0.001, for each relationship). For age and AST, the extent of the linear relationships (extrapolated from population average values) included a 4% decrease in CL/F for every decade increase and a 6% decrease in CL/F for every 10‐unit increase, respectively. Following co‐administration of CYP3A4 potential inhibitors, a 14% decrease in CL/F was estimated. Only body weight was found to significantly (P<0.001) influence V/F (a 6% increase in V/F for every 10‐kg increase).Conclusions  The pharmacokinetics of, and covariate influences on, sildenafil in patients with erectile dysfunction were shown to be consistent with those demonstrated in phase I volunteer studies.