bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prognostic significance of the circumferential resection margin following total mesorectal excision for rectal cancer
Authors: Wibe A , Rendedal P R , Svensson E , Norstein J , Eide T J , Myrvold H E , Søreide O 
Published: March 2003

Abstract

Background
Knowledge of prognostic factors following resection of rectal cancer may be used in the selection of patients for adjuvant therapy. This study examined the prognostic impact of the circumferential resection margin on local recurrence, distant metastasis and survival rates.

Methods
A national population-based rectal cancer registry included all 3319 new patients from November 1993 to August 1997. Some 686 patients underwent total mesorectal excision with a known circumferential margin. This shortest radial resection margin was measured in fixed specimens. None of the patients had adjuvant radiotherapy.

Results
Following potentially curative resection and after a median follow-up of 29 (range 14–60) months, the overall local recurrence rate was 7 per cent (46 of 686 patients): 22 per cent among patients with a positive resection margin and 5 per cent in those with a negative margin (margin greater than 1 mm). Forty per cent of patients with a positive margin developed distant metastasis, compared with 12 per cent of those with a negative margin. With decreasing circumferential margin there was an exponential increase in the rates of local recurrence, metastasis and death.

Conclusion
The circumferential margin has a significant and major prognostic impact on the rates of local recurrence, distant metastasis and survival. Information on circumferential margin is important in the selection of patients for postoperative adjuvant therapy.
Right-lobe live donor liver transplantation improves survival of patients with acute liver failure
Authors: Liu C L , Fan S T , Lo C M , Yong B H , Fung A S M , Wong J 
Published: March 2003

Abstract

Background
Right-lobe live donor liver transplantation (LDLT) is used by many liver transplant centres for treating adult patients with terminal liver disease, but its incremental benefit for the intended recipient over cadaveric liver graft transplantation has not been determined. The impact of LDLT as a proactive approach on the outcome of patients with acute liver failure was analysed.

Methods
From January 1999 to March 2001, right-lobe LDLT was offered proactively to 50 consecutive patients with acute liver failure and their families. The outcome of those who opted for right-lobe LDLT (n = 34) was compared with that of those who did not opt for LDLT (n = 16).

Results
In the group that opted for right-lobe LDLT, 16 patients eventually received a live donor right-lobe graft (14 patients survived) and three patients received a cadaveric liver graft that became available while the potential live donor was undergoing evaluation (all three patients survived). Among the group who did not opt for LDLT, only one patient received a cadaveric liver graft and survived. The former group had a higher overall survival rate (17 of 34 versus one of 16). With a proactive approach, the overall transplant rate was increased from four of 50 to 20 of 50. The morbidity rate among donors was low and none died.

Conclusion
Right-lobe LDLT improves the overall survival rate of patients with acute liver failure and should be considered as one of the treatment options for adult patients with acute liver failure.
Diethylmaleate, a pro-oxidant, attenuates experimental ischaemia–reperfusion-induced lung injury
Authors: Kiely P D , Wang J C , Kelly C J , Condron C , Watson R G K , Bouchier-Hayes D J 
Published: March 2003

AbstractBackgroundSystemic ischaemia–reperfusion (IR) injury is in part an oxidant injury mediated by neutrophils. Diethylmaleate (DEM), an intracellular pro-oxidant agent, has been shown to alleviate neutrophil-mediated tissue injury. The aim of this study was to evaluate whether DEM could have a protective effect on neutrophil-mediated lung injury in an animal model of lower-torso IR.MethodsSprague–Dawley rats (seven per group) were randomized into three groups. The control group underwent midline laparotomy only; the IR group underwent laparotomy and clamping of the infrarenal abdominal aorta for 30 min followed by 2 h of reperfusion; and the third group was pretreated with DEM 6 mmol/kg intraperitoneally 1 h before the IR insult.ResultsIR resulted in a significant increase in both microvascular leakage and pulmonary neutrophil infiltration as measured by bronchoalveolar lavage protein concentration and pulmonary myeloperoxidase activity respectively. Pretreatment with DEM significantly attenuated both microvascular leakage and neutrophil infiltration.ConclusionPreconditioning with DEM protected against IR-induced lung injury. This protective effect raises the possibility of using pro-oxidants to prevent inflammatory injury.
Comparison of magnetic resonance cholangiography and percutaneous transhepatic cholangiography in the evaluation of bile duct strictures after cholecystectomy
Authors: Chaudhary A , Negi S S , Puri S K , Narang P 
Published: March 2003

Abstract

Background
Percutaneous transhepatic cholangiography (PTC) has been the preferred investigation to delineate the anatomy of the biliary tract in a patient with a bile duct stricture after cholecystectomy. Recently magnetic resonance cholangiography (MRC) has been described to evaluate the obstructed biliary tract. This paper reports a comparison of MRC with PTC in evaluating patients with an iatrogenic bile duct stricture.

Methods
This was a prospective study of 26 patients who had surgery for a bile duct stricture after cholecystectomy. Before operation all patients underwent both MRC and PTC, the results of which were compared with the intraoperative findings.

Results
Both PTC and MRC were comparable with regard to image quality, detection of intrahepatic bile duct dilatation, assessment of the level of injury and detection of abnormalities such as intraduct calculi, cholangitic liver abscesses and atrophy of liver lobes. MRC provided additional information in four patients, including detection of associated fluid collections (n = 3) and portal hypertension (n = 1). In eight patients more than one puncture had to be performed during PTC to delineate the complete anatomy.

Conclusion
MRC is an accurate and non-invasive imaging procedure for preoperative evaluation of patients with a bile duct injury after cholecystectomy, and is capable of providing additional information which may not be available with PTC.
In vivo activation of plasma membrane H+‐ATPase hydrolytic activity by complex lipid‐bound unsaturated fatty acids in Ustilago maydis
Authors: Hernández Agustín , Cooke David T. , Clarkson David T. 
Published: March 2003

As an adaptation process to the growth retardation provoked by the presence of nonlethal concentrations of ergosterol biosynthesis inhibitors, Ustilago maydis alters the ratio of linoleic to oleic acid bound to plasma membrane complex lipids [Hernández, A., Cooke, D.T., Lewis, M. & Clarkson, D.T. (1997) Microbiology143, 3165–3174]. This alteration increases plasma membrane H+‐ATPase hydrolytic activity. Activation of H+‐ATPase by the linoleic/oleic acid proportion is noncompetitive, nonessential and only involves changes in the maximum velocity of the pump. Optimum pH, affinity to MgATP and constants for the inhibition by vanadate and erythrosin B remain unchanged. This all indicates that activation of plasma membrane	H+‐ATPase by unsaturated fatty acids differs clearly from glucose‐induced activation observed in yeast. Also, it is a physiologically relevant event similar to other, as yet uncharacterized, changes in plasma membrane H+‐ATPase hydrolytic activity observed in plants and fungi, as part of an adaptation process to different stress conditions.
The SK‐N‐MC cell line expresses an orexin binding site different from recombinant orexin 1‐type receptor
Authors: Wieland Heike A. , Söll Richard M. , Doods Henri N. , Stenkamp Dirk , Hurnaus Rudolf , Lämmle Bärbel , Beck‐Sickinger Annette G. 
Published: March 2003

Orexin A and B (also known as hypocretins), two recently discovered neuropeptides, play an important role in food intake, sleep/wake cycle and neuroendocrine functions. Orexins are endogenous ligands of two G‐protein‐coupled receptors, termed OX1 and OX2. This work presents the first short orexin A and B analogues, orexin A 23–33 and orexin B 18–28, with high affinity (119 ± 49 and 49 ± 23 nm) for OX1 receptors expressed on SK‐N‐MC cells and indicates the importance of the C‐terminal part of the orexin peptides for this ligand–receptor interaction. However, these C‐terminal fragments of orexin did not displace the	125I‐labelled orexin B from the recombinant orexin 1 receptor stably expressed in Chinese hamster ovary cells. To examine the role of the shortened orexin A 23–33 in feeding, its effects in mimicking or antagonizing the effects of orexin A were studied in rats after administration via the lateral hypothalamus. In contrast with orexin A, which potently induced feeding up to 4 h after administration, orexin A 23–33 neither induced feeding nor inhibited orexin A‐induced feeding. Modafinil (Vigil®), which was shown earlier to activate orexin neurons, displayed binding neither to the orexin receptor expressed on SK‐N‐MC cells nor to the recombinant orexin 1 receptor, which indicates that modafinil displays its antinarcoleptic action via another yet unknown mechanism. PCR and subsequent sequencing revealed expression of the full‐length orexin 1 receptor mRNA in SK‐N‐MC and NT‐2 cells. Interestingly, sequencing of several cDNA clones derived from RNA of both SK‐N‐MC and NT‐2 cells differed from the published nucleotide sequence at position 1375. Amino acid prediction of this A→G change results in an isoleucine→valine substitution at the protein level, which may provide evidence for an editing process.
Rapid caspase‐dependent cell death in cultured human breast cancer cells induced by the polyamine analogue N1,N11‐diethylnorspermine
Authors: Hegardt Cecilia , Johannsson Oskar T. , Oredsson Stina M. 
Published: March 2003

The spermine analogue N1,N11‐diethylnorspermine (DENSPM) efficiently depletes the cellular pools of putrescine, spermidine and spermine by down‐regulating the activity of the polyamine biosynthetic enzymes and␣up‐regulating the activity of the catabolic enzyme spermidine/	spermine N1‐acetyltransferase (SSAT). In the breast cancer cell line L56Br‐C1, treatment with 10 µm DENSPM induced SSAT activity 60 and 240‐fold at 24 and 48 h after seeding, respectively, which resulted in polyamine depletion. Cell proliferation appeared to be totally inhibited and within 48 h of treatment, there was an extensive apoptotic response. Fifty percent of the cells were found in the sub‐G1 region, as determined by flow cytometry, and the presence of apoptotic nuclei was morphologically assessed by fluorescence microscopy. Caspase‐3 and caspase‐9 activities were significantly elevated 24 h after seeding. At 48 h after seeding, caspase‐3 and caspase‐9 activities were further elevated and at this time point a significant activation of caspase‐8 was also found. The DENSPM‐induced cell death was dependent on the activation of the caspases as it was inhibited by the general caspase inhibitor Z‐Val‐Ala‐Asp fluoromethyl ketone. The results are discussed in the light of the L56Br‐C1 cells containing mutated BRCA1 and p53, two genes involved in DNA repair.
The relationship between airway hyper‐responsiveness, markers of inflammation and lung function depends on the duration of the asthmatic disease
Authors: Grönke L. , Kanniess F. , Holz O. , Jörres R. A. , Magnussen H. 
Published: March 2003

Background The combination of airway hyper‐responsiveness, eosinophilic airway inflammation, and lung function impairment is considered as a hallmark of bronchial asthma. Since airway function might change with time in chronic asthma, the association between parameters which are characteristic of asthma could be different in subjects with different durations of the disease.Objective We assessed whether in patients with asthma the relationship between airway hyper‐responsiveness, non‐invasive markers of airway inflammation, and baseline lung function depended on the duration of the disease.Methods Sixty‐six non‐smoking patients with mild to moderate allergic asthma without corticosteroids were assigned to two groups, according to a duration of the disease (time interval since doctor's diagnosis) of either ≤ 16 years (median 8 years; mean FEV1, 92.6% pred.; n = 34) or > 16 year (median 25 years; mean FEV1, 87.9% pred.; n = 32).Results Groups did not differ statistically in PC20FEV1 of methacholine, sputum composition, levels of exhaled nitric oxide (NO), lung function parameters, or history of treatment. There were significant correlations between PC20FEV1, eosinophils and NO in patients with a duration of the disease ≤ 16 year, but no relation to lung function. In contrast, patients with a duration > 16 year showed a correlation between PC20FEV1 of methacholine and lung function but not eosinophils or NO. In both groups, eosinophils and NO were associated with each other. These results were corroborated by the statistical procedure of factor analysis that revealed ‘inflammation’ and ‘lung function’ as major entities and found ‘responsiveness’ to be associated with only one of them in each group.Conclusion Our data demonstrate that with a shorter duration of the asthmatic disease airway hyper‐responsiveness is associated with airway inflammation, whereas with a longer duration it is associated with impaired lung function, suggesting that in chronic asthma ongoing alterations become the primary determinant of functional characteristics.
Slow recovery of boreal forest ecosystem following decreased nitrogen input
Authors: Strengbom J. , Nordin A. , Näsholm T. , Ericson L. 
Published: March 2003

Summary

Ecosystem recovery after decreased input of nitrogen was examined in two different fertilization experiments where the fertilization had been terminated for 9 and 47 years, respectively.
The species composition of the understorey vegetation showed no signs of recovery 9 years after the fertilization was terminated. Increased sporocarp production of mycorrhizal fungi was seen on formerly fertilized plots compared with plots still receiving N, but the species composition showed large differences compared to control plots.
In the second experiment, examined 47 years after termination of fertilization, N favoured bryophytes such as Brachythecium reflexum (Starke) Schimp., Plagiothecium denticulatum (Hedw.) Schimp. and the leaf‐parasitic fungus Valdensia heterodoxa Peyronel (attacking Vaccinium myrtillus L.) was more abundant in the formerly N‐treated plots than in controls. The abundance of Hylocomium splendens (Hedw.) Schimp., the most common bryophyte under normal N conditions, showed a contrasting pattern, with less abundance in the formerly N‐treated plots than in controls. Sporocarp production of N‐sensitive mycorrhizal fungi was lower in the formerly N‐treated plots. No difference in plant species composition was noticed for vascular plants.
These results contrast with other studies that have interpreted reduced N leakage and nutrient levels in trees after decreased N input as a rapid ecosystem recovery. The present study suggests that the time needed for recovery of the ecosystem biota may be substantial in originally N‐limited ecosystems.
A new method of growth analysis for plants that experience periodic losses of leaf mass
Authors: ANTEN N. P. R. , ACKERLY D. D. 
Published: March 2003

Summary

A new method (the iterative approach) is presented by which growth analyses can be conducted on plants that have been subjected to significant losses in biomass and leaf area between harvests. The method is particularly useful to analyse the effects of defoliation on growth and biomass allocation.
Values for the following parameters can be estimated: absolute growth rate (g day−1), relative growth rate (RGR, g g−1 day−1), net assimilation rate (NAR, g m−2 day−1), leaf area ratio (LAR, m2 g−1), fraction of newly assimilated mass that is allocated to leaf lamina production (flam, g g−1), and daily fractional change in the average specific leaf area of plants (ρ, day−1). These parameters are determined by means of iterations. We defined a number of growth functions, and the values of NAR, flam and the SLA of newly produced leaves were changed until these functions correctly predicted the measured total plant mass, leaf lamina mass and leaf area at the end of the growth period. This avoids having to assume a constant relationship between leaf area and biomass (as in the ‘classical’ approach), and it avoids the use of polynomial functions to fit growth data (as in the ‘functional’ approach) that are unsuitable for fitting data sets exhibiting discontinuities such as abrupt changes in biomass.
The method was applied to a greenhouse experiment in which we analysed the effects of sustained defoliation on growth and biomass allocation in a tropical understorey palm, Chamaedorea elegans Mart.
We showed that C. elegans plants respond to defoliation with a considerable increase in the allocation of new assimilates to lamina growth (flam) and that, despite the repeated loss of leaf area and associated reductions in LAR, they had RGR values that were similar to those of undamaged plants.
Fine root demography and morphology in response to soil resources availability among xeric and mesic sandhill tree species
Authors: Espeleta J. F. , Donovan L. A. 
Published: March 2003

Summary

Optimality theory suggests that roots should be kept alive until the efficiency of resource acquisition is maximized (i.e. a maximum ratio of benefits to costs). Because root efficiency may vary with environmental conditions, ecological distributions of plant species may be linked to different patterns of root demography.
In a greenhouse study, we investigated fine root turnover (growth and death) for three woody species from the fall‐line sandhills of the south‐eastern USA. Pinus palustris Mill. is a generalist in this habitat, whereas Quercus marilandica Muenchh. occurs in more fertile, mesic habitats relative to Quercus laevis Walt. Seedlings were grown under four resource treatments (water + nutrients) for 7 months: high resources, low resources, and short‐term exposure (last 2 months of the study) to resource enrichment or depletion.
Increasing fine root longevity may be optimal in resource‐poor sites because root efficiency may be maximized by less root turnover and resource loss. As expected, fine root death and growth was less in species from xeric habitats (Q. laevis), but greater in species from mesic habitats (Q. marilandica). The generalist species P. palustris exhibited high growth but little death of fine roots.
When soil resources decrease, less root turnover may reduce resource loss. Fine root growth of all three species decreased at low resources. Fine root death decreased at low resources in Q. marilandica, the only species with significant root death.
Demographic responses differed between fine roots and leaves. Although leaf and fine root death were greater in Q. marilandica than in Q. laevis, leaf death, unlike root death, did not change with resource availability. Short‐term resource enrichment or depletion affected leaf production but not fine root demography in the Quercus species.
Given that fine root morphology affects root maintenance and construction costs, we expected greater fine root growth and death in species with thinner roots of high specific root length (SRL) and low density. However, the species with the greatest root turnover, Q. marilandica, had thick and dense roots of low SRL.
Results from our study with woody species indicate that fine root demography, but not fine root morphology, was linked to ecological distribution in a narrow geographical range. Differences in fine root turnover under different resource availability were consistent with the optimality theory, and may reflect trade‐offs between tolerance and competitive ability below ground: less root turnover of xeric species under low fertility may conserve resources, whereas faster root growth of mesic species potentially maximizes resource uptake in more fertile soils.
Ecosystem respiration in two Mediterranean evergreen Holm Oak forests: drought effects and decomposition dynamics
Authors: Reichstein M. , Tenhunen J. D. , Roupsard O. , Ourcival J.‐M. , Rambal S. , Dore S. , Valentini R. 
Published: March 2003

Summary

We present ecosystem respiration data from two Mediterranean forest sites in central Italy (Castelporziano) and southern France (Puéchabon) in order to analyse the role of soil drought and decomposition dynamics using different models.
Ecosystem respiration was derived from continuous eddy covariance measurements. The entire data set was separated into 5‐day periods. For each period a function depending on three parameters was fitted to the scatter of eddy CO2 flux versus photosynthetic photon flux density. The y intercept of each curve was taken as an estimate of the average night‐time ecosystem respiration during the period. The ecosystem respiration was analysed with different regression models as a function of soil water content and temperature.
Ecosystem respiration ranged from 1 to 7 µmol m−2 s−1 and showed a clear seasonality, with low rates during drought periods and in winter. The regression model analysis revealed that in drier soil, ecosystem respiration was more sensitive to soil moisture than is expressed by the often used hyperbolic model.
In contradiction to a simple multiplicative model, the Q10 of ecosystem respiration was not independent of moisture, but increased from nearly 1·0 at low moisture to above 2·0 at field capacity. Several explanations are discussed.
Of the variance in ecosystem respiration, 70–80% was explained with a model where Q10 of ecosystem respiration is a function of soil water content.
For the Puéchabon site, a soil carbon‐balance model predicted only small changes in litter pool size (max. 7%), which caused only minor changes in soil microbial respiration (0·1 µmol m−2 s−1). In contrast, the contribution of microbial regrowth dynamics to ecosystem respiration is estimated to be substantial (≈1·6 µmol m−2 s−1). The model predicted that soil microbial respiration probably provides the largest contribution to ecosystem respiration (≈50%). The importance of below‐ground processes for ecosystem C balances is thus emphasized.