bluuebunny/crossref_metadata_2025_split huggingface dataset:
Competition and character displacement in two species of scincid lizards
Authors: Melville Jane 
Published: March 2003

AbstractThe role of competition in habitat occupation and character displacement is investigated in two species of alpine lizards (Niveoscincus microlepidotus and N. greeni), using both controlled competition experiments and field‐based ecological work. Competition experiments demonstrate that interspecific aggression occurs between these closely related species, with the larger and more aggressive N. greeni being socially dominant. When these species occur in sympatry, N. microlepidotus was found to shift its habitat occupation to the heathlands, which provide less thermal opportunities. In addition, a reduction in body size occurred in both adult and neonatal N. microlepidotus at sympatric field sites. Differences in body size between N. microlepidotus and N. greeni in sympatry were significantly greater than in allopatry, indicating that character displacement is occurring. Results, combined with previous molecular and biogeographical data, suggest that there is a trend towards a reduction in body size and a restriction in habitat occupation in N. microlepidotus in the north‐east periphery of its distribution, which is shaped by competition with N. greeni.
Resource quantity, not resource heterogeneity, maintains plant diversity
Authors: Stevens M. Henry H. , Carson Walter P. 
Published: March 2003

AbstractResource heterogeneity has often been proposed to explain the maintenance of plant species diversity and patterns of species diversity along productivity gradients. Resource heterogeneity should maintain biodiversity by preventing competitive exclusion because different species are superior competitors in different parts of a heterogeneous environment. In natural systems, however, resource heterogeneity covaries with average resource supply rate, making the effect of heterogeneity difficult to isolate. Using a novel experimental approach, we tested the independent effects of resource heterogeneity and average supply rate on plant species diversity. We show that the average supply rate of the most limiting resource controlled species diversity, whereas heterogeneity of this resource had virtually no effect. These findings also suggest that biodiversity declines with increasing productivity because at high enough levels of productivity one resource may always be driven to sufficiently short supply to exclude many species.
Simple temporal models for ecological systems with complex spatial patterns
Authors: Pascual Mercedes , Roy Manojit , Franc Alain 
Published: March 2003

AbstractSpatial patterns are ubiquitous in nature. Because these patterns modify the temporal dynamics and stability properties of population densities at a range of spatial scales, their effects must be incorporated in temporal ecological models that do not represent space explicitly. We demonstrate a connection between a simple parameterization of spatial effects and the geometry of clusters in an individual‐based predator–prey model that is both nonlinear and stochastic. Specifically we show that clusters exhibit a power‐law scaling of perimeter to area with an exponent close to unity. In systems with a high degree of patchiness, similar power‐law scalings can provide a basis for applying simple temporal models that assume well‐mixed conditions.
Structure and carbohydrate analysis of the exopolysaccharide capsule of Pseudomonas putida G7
Authors: Kachlany Scott C. , Levery Steven B. , Kim John S. , Reuhs Bradley L. , Lion Leonard W. , Ghiorse William C. 
Published: March 2003

The aromatic hydrocarbon‐degrading bacterium, Pseudomonas putida G7, produces exopolymers of potential interest in biotechnological applications. These exopolymers have been shown to have significant metal‐binding ability. To initiate the study of the metal–polymer interactions, we explored the physical and chemical nature of the P. putida G7 exopolysaccharide, a major component of the exopolymer. A capsular structure was observed by light microscopy surrounding both planktonic and attached cells in biofilms after immunofluorescence staining with polyclonal antiserum raised against planktonic cells. Further work with planktonic cells showed that the immunostained capsule remained associated with young (log phase) cells, whereas older (stationary phase) cells lost their capsular material to the external milieu. Visualization of frozen, hydrated stationary phase cells by cryo‐field emission scanning electron microscopy (cryoFESEM) revealed highly preserved extracellular material. In contrast, conventional scanning electron microscopy (SEM) of stationary phase cells showed rope‐like material that most probably results from dehydrated and collapsed exopolymer. Both capsular and released exopolymers were separated from cells, and the released extracellular polysaccharide (EPS) was purified. Deoxycholate–polyacrylamide gel electrophoresis (PAGE) and silver/alcian blue staining of the partially purified material showed that it contained both EPS and lipopolysaccharide (LPS). Further purification of the EPS using a differential solubilization technique to remove LPS yielded highly purified EPS. Gas chromatography–mass spectrometry revealed that the purified EPS contained the monosaccharides, glucose, rhamnose, ribose, N‐acetylgalactosamine and glucuronic acid. The structural and chemical properties of the P. putida EPS described here increase our understanding of the mechanisms of toxic metal binding by this well‐known Proteobacterium.
Microbial community of a saline mud volcano at San Biagio‐Belpasso, Mt. Etna (Italy)
Authors: Yakimov Michail M. , Giuliano Laura , Crisafi Ermanno , Chernikova Tatyana N. , Timmis Kenneth N. , Golyshin Peter N. 
Published: March 2003

SummaryIn San Biagio of Belpasso, approximately 20 km south of Mt. Etna, in the area of contact between volcanic and sedimentary formations, a number of small (3– 60 cm in diameter) active mud eruptions discharge CO2‐rich gases, mud
and NaCl brines. They can be described as mini‐volcanoes owing to their typical conic
shapes and continuously bubbling peak craters. Samples were collected from the active
peak craters at a depth of 20 cm and DNA was immediately extracted and amplified
with universal 16S rRNA gene‐specific primers, followed by cloning procedure. A total
of 140 bacterial clones obtained were screened and clustered by restriction fragment
length polymorphism (RFLP) analysis. The pool of 16S rRNA sequences representing
each RFLP cluster was subjected to phylogenetic analysis. All of the 33 sequences
analysed were affiliated with the kingdom of Eubacteria; 28 sequences (77%
of all clones) affiliated with the Proteobacteria, two sequences (19%
of all clones) were affiliated with Actinobacteria and three sequences (4%
of all clones) were affiliated with the Flexibacter‐Cytophaga‐Bacteroides
division. The data obtained suggest that the microorganisms phylogenetically affiliated
to autotrophic methane oxidizers and heterotrophic hydrocarbon degraders belonging
to the gamma‐subclass of Proteobacteria are major constituents of the microbial communities of the saline volcanic muds. Overall, the composition of the microbial community of the San Biagio mud volcano resembles the compositions of marine microbial communities, which might indicate that wind‐blown seawater vapour acted as an inoculum for microbial community described in present work.
Prokaryotic phylogenetic diversity and corresponding geochemical data of the brine–seawater interface of the Shaban Deep, Red Sea
Authors: Eder Wolfgang , Schmidt Mark , Koch Marcus , Garbe‐Schönberg Dieter , Huber Robert 
Published: March 2003

SummaryThe interface between the hypersaline brine and the overlying sea‐water (brine–seawater interface) of the Shaban Deep, northern Red Sea was investigated for the presence of microorganisms using the 16S rRNA gene as a molecular marker. Samples of the south and east basin (depth: 1331 m and 1332 m respectively) were selected to ascertain the microbial diversity of this extreme and, so far, unexplored environment. Phylogenetic analysis revealed novel lineages within the Bacteria, the Crenarchaeota and the Euryarchaeota. Novel representatives of the KB1 sequence group (Eder et al., 1999 Arch Microbiol 172: 213–218) were detected indicating a widespread distribution of the corresponding Bacteria in Deep Sea brine pools. Our results contribute to the understanding of the hitherto unknown microbial diversity at the chemical gradient of the Shaban Deep, and suggest the presence of novel Bacteria and Archaea thriving under extreme environmental conditions.
Alkane hydroxylase homologues in Gram‐positive strains
Authors: Van Beilen Jan B. , Smits Theo H. M. , Whyte Lyle G. , Schorcht Susanne , Röthlisberger Martina , Plaggemeier Thorsten , Engesser Karl‐Heinrich , Witholt Bernard 
Published: March 2003

SummaryWe isolated Gram‐positive alkane‐degraders from soil and a tricking‐bed reactor, and show using polymerase chain reaction (PCR) with degenerate alkane hydroxylase primers and Southern blots that most Rhodococcus isolates contain three to five quite divergent homologues of the Pseudomonas putida GPo1 alkB gene. Two Mycobacterium isolates each contain one homologue, however there is no evidence for the presence of alkB homologues in the remaining strains.
Histopathologic characteristics of advanced colorectal cancer smaller than 2 cm in size
Authors: Adachi  , Yasuda  , Kakisako  , Sato  , Shiraishi  , Kitano  
Published: March 2003

PurposeScreening for colorectal cancer results in an increased incidence of early detection and decreased mortality. Although small colorectal cancer with deep invasion or lymph node metastasis is sometimes encountered, there is no comprehensive study evaluating the histopathologic features of such tumours. The aim of this study was to clarify the characteristics of advanced colorectal cancer <2 cm in size.MethodsUsing a series of 317 patients who underwent surgery for colorectal cancer, pathologic features were compared among small advanced cancers <2 cm invading the muscularis propria or subserosa (T2, T3) or involving the lymph nodes (N1, N2) (n = 22), small early cancers <2 cm invading only the mucosa or submucosa (T1) without lymph node metastasis (N0) (n = 24), and ordinary advanced cancers> 2 cm (n = 271).ResultsSmall advanced cancers were clearly different from small early cancers in gross appearance, histological type, frequency of serosal invasion (18% vs 0%, P < 0.05), lymph node metastasis (36% vs 0%, P < 0.01), and concomitant adenomatous component (17% vs 48%, P < 0.05). Small advanced cancers, when compared with ordinary advanced cancers, were characterized by the grossly superficial type (14% vs 1%, P < 0.01) and absence of serosal invasion (82% vs 14%, P < 0.01) However, the two groups were not significantly different with regard to the frequency of lymph node metastasis (36% vs 53%), liver metastasis (5% vs 15%), and stage of the disease (Dukes’ A and B; 64% vs 45%).ConclusionThe results indicate that colorectal cancers, once they invade beyond the submucosa, have the same metastatic potential, irrespective of tumour size. The low frequency of concomitant adenoma implies de novo carcinogenesis of the small advanced cancers.
Quantitative radio‐isotope proctography—a new technique for the assessment of rectal evacuation
Authors: Vijaya‐Sekaran  , Nguyen  , Groom  , Levitt  
Published: March 2003

Objective The aim of this study was to establish a technique for measuring both the efficiency and speed of rectal evacuation and to assess the impact on these parameters of varying the volume of instillate.Subjects and methods Twelve healthy volunteers had 100 ml, 150 ml and 200 ml of isotope‐labelled paste inserted into the rectum on three separate occasions and asked to evacuate the paste on a modified commode. Radioactivity within the rectal field was measured at 2‐s intervals. The speed of evacuation from both the time at which the command to evacuate was given and the time at which evacuation commenced and efficiency of evacuation were calculated.Results The efficiency of evacuation differed little with the changing volumes of instillate (median values 69%, 68% and 67% for 100 ml, 150 ml and 200 ml, respectively). The speed of evacuation increased with increasing volumes of instillate and was significantly faster when comparing the 200‐ml group with the 100‐ml group (Wilcoxon rank sum test for paired data, P < 0.05). The increase in speed of rectal emptying was, however, due to earlier initiation of evacuation rather than a faster rate of rectal emptying.Conclusions The findings suggest that quantitative tests of rectal emptying should use a set volume of instillate to avoid variations in the speed of evacuation and indicate that a larger volume of instillate may be preferable to smaller volumes for the purposes of testing rectal emptying.
Biofeedback for anismus: has placebo effect been overlooked?
Authors: Meagher  , Sun  , Kennedy  , Smart  , Lubowski  
Published: March 2003

ObjectiveMultiple uncontrolled studies have concluded that biofeedback is successful in treating anismus. This study’s objective was to assess the physiological effects of placebo and biofeedback treatment on patients with anismus and to correlate changes with clinical improvement.Patients and methodsTwelve patients with symptoms and electrophysiological findings of anismus were studied. Initial assessment included a detailed history, symptom assessment by linear analogue scales, anorectal manometric and electrophysiological studies, colon transit scintigraphy, and scintigraphic proctography. Patients underwent 5 days of placebo treatment, followed 1 week later by re‐assessment of symptoms and physiological studies. Five days of biofeedback was then given followed by another complete re‐assessment 1 week later. A final interview was performed 2 months later. All assessments were by an independent observer who was not responsible for the treatments.ResultsSeven patients reported an overall improvement in symptoms following placebo treatment. A total of seven patients reported improvement following biofeedback, three of whom had already reported an improvement with placebo. One patient who reported improvement following placebo had worsening of symptoms following biofeedback. The only symptoms or tests which changed more with biofeedback than placebo were anal pressure and electromyographic activity on attempted defaecation in the left lateral position. There was no demonstrable correlation between change in symptoms and change in physiological tests. The scintigraphic ‘ejection fraction’ of the rectum was unchanged by treatment.ConclusionClinical improvement in previous studies may in part be due to placebo effect and observer bias. Improvement with biofeedback may be due to physiological changes which are not detected with conventional anorectal physiological tests.
Guidelines for the surveillance and management of familial adenomatous polyposis (FAP): a world wide survey among 41 registries
Authors: Vasen  , Bülow  ,   The Leeds Castle Polyposis Group
Published: March 2003

Objectives FAP is an autosomal dominant disease characterized by numerous adenomas in the colorectum. The majority of patients also develop adenomas in the duodenum. The purpose of the study was to evaluate the management and screening protocols implemented in FAP families at various polyposis registries in the world.Methods A questionnaire was mailed to the members of The Leeds Castle Polyposis Group requesting information on: diagnostic evaluation of polyposis, recommendations for screening and surgical management of the colon, surveillance of the upper gastrointestinal tract and the management of duodenal polyposis.Results Almost all members agreed that a newly diagnosed patient should be referred to a polyposis registry and to a clinical genetics centre for genetic counselling and DNA testing. If the mutation has been detected in the family, DNA testing should be offered to first‐degree relatives of patients from age 10–12 years onwards. The surveillance protocol generally advised includes sigmoidoscopy from age 10–12 years at 2‐year intervals until age 40 years. There was no agreement on the preferred surgical treatment of colonic polyposis. Almost all members advised follow up after colonic surgery. Surveillance of the duodenum was recommended by most members; this would start from age 30 years. There was no agreement on the preferred surgical treatment of duodenal polyposis, or on the indication for operation.Conclusion This survey provides insight into the guidelines used at various polyposis registries for the surveillance and management of FAP patients, and this insight may contribute to the appropriate management of these patients.
The significance of hyperamylasaemia after colonic resection
Authors: Griffith  , Eu  , Leong  , Ho  , Nyam  , Seow‐Choen  
Published: March 2003

ObjectiveColonic resection may be complicated by prolonged post‐operative paralytic ileus. Post‐operative hyperamylasaemia and pancreatitis may sometimes follow abdominal surgery or occasionally trauma. Post‐operative ileus seen after colectomy may be secondary to unrecognized pancreatitis and hyperamylasaemia. The aims of this study were to identify the incidence of hyperamylasaemia after colonic resection, to investigate the effect of hyperamylasaemia on post‐operative intestinal function and to correlate any changes with extent of colorectal resection.Patients and methodsThe serum amylase was determined prospectively in a consecutive series of 150 patients who underwent elective colorectal resection. Serum amylase was measured before surgery and post‐operatively until it returned to within the normal range.ResultsHyperamylasaemia occurred in 28 patients (18.7%) after colorectal surgery. Serum amylase levels returned to normal in all but seven patients (4.7%) by the second post‐operative day. The development of hyperamylasaemia did not adversely influence the post‐operative course. Both groups of patients had similar restoration of intestinal function and were discharged home on equivalent days. Ligation of the middle colic artery alone was found to be significantly associated with hyperamylasaemia by multivariate stepwise logistic regression analysis.ConclusionTwenty‐eight out of 150 patients who underwent colorectal resection developed hyperamylasaemia after surgery. The incidence was highest in patients with middle colic artery ligation. The development of post‐operative hyperamylasaemia does not seem to influence adversely the post‐operative course in this series.
Does the caseload of the pathologist influence the minimum and extended data set of pathology variables reported for rectal adenocarcinoma?
Authors: Hatzidis  , Solomon  , Schnitzler  , Cartmill  , Loder  , Chapuis  
Published: March 2003

BackgroundThe role of adjuvant therapy for rectal carcinoma, both radiotherapy and chemotherapy, remains controversial. Nevertheless, some stages of rectal cancer may benefit from adjuvant therapies. Post‐operative decision making is determined by accurate pathology staging of the tumour which may depend on the experience, expertise and activity of the pathologist and by surgeon variables.MethodsPathology reports for consecutive rectal cancer resection specimens at five University of Sydney teaching hospitals were assessed for the presence of important pathology variables. The desired minimum data set included the assessment of six major variables: extent of tumour penetration, distal and circumferential margins, degree of differentiation, number of nodes and identification of an apical node. A multivariate analysis was performed to see if the activity of the pathologist (number of specimens reported in time period) correlated with the number of minimum data set pathology variables reported. Multivariate analysis was also used to determine if the activity (number of resections) or training (colorectal society vs non‐society) of the surgeon were correlated with variables potentially related to adequate surgical clearance of the tumour and to abdominoperineal (APE) resection rates.ResultsFour hundred and forty‐five consecutive rectal cancer pathology reports were reviewed. Of the minimum data set (six variables) only 17% of the reports documented all of these major variables (range 2–6). Apical node identification was reported in only 47% of reports and circumferential margin in only 39%. Circumferential margin was reported significantly more frequently in the higher activity group of pathologists (51% vs 29%, P=0.00001). APE rates were significantly different between some of the hospitals (range 19–31%). Surgeons performing more than 20 resections had lower APE rates (16% vs 37%, P=0.000 001) than those with less than 20 resections. There was no difference in APE rates between society and non‐society surgeons. Distal margins of <2 cm for anterior resections were significantly higher in non‐society surgeons (52% vs 36%, P=0.004).DiscussionStandardized reporting, template proformas and perhaps dedicated gastrointestinal pathologists may improve reporting of surgical rectal cancer specimens.
Emergency admission for surgery predicts disease progression during adjuvant 5‐Fluouracil (5‐FU)‐based chemotherapy
Authors: Hayman  , James  
Published: March 2003

ObjectiveTo determine the prognostic significance of a number of variables in patients that receive adjuvant chemotherapy for colorectal cancer.Patients and methodsWe reviewed the Cancer Centre records of 194 patients who received adjuvant chemotherapy following potentially curative resection of Dukes’ B or C colorectal cancer. Eight variables were examined to determine which factor(s) predicted disease progression during the 6‐month chemotherapy period.ResultsAdmission for emergency resection (due to bowel obstruction or perforation) rather than elective resection, and a poorly differentiated tumour rather than moderately/well differentiated were independent significant factors in predicting disease progression (P < 0.001 and P=0.011, respectively). However, sex, age, Dukes’ stage, number of involved lymph nodes, delays in starting chemotherapy and compliance with chemotherapy regime had no significant effect on 6‐month tumour progression.ConclusionThese preliminary findings confirm data which suggest that emergency admission patients may suffer from intrinsically more aggressive disease than the average population with colorectal cancer.
Plasma TIMP‐1—a marker of metastasis in colorectal cancer
Authors: Simpson  , Hemingway  , Thompson  
Published: March 2003

ObjectiveTo assess a potential role for plasma assay of TIMP‐1 and MMP‐9 as markers of disease presence and disease stage in colorectal cancer.Patients and methodsPlasma concentration of  TIMP‐1 and MMP‐9 was measured in 41 patients with proven colorectal cancer and in 20 age/sex‐matched controls. In the 38 cancer patients who underwent laparotomy, portal plasma samples were collected in addition to peripheral venous samples, to assess whether these might be a more sensitive indicator of disease severity.ResultsIn samples taken preoperatively, systemic plasma levels of both TIMP‐1 and MMP‐9 were significantly elevated in cancer patients compared with controls (P < 0.0001 and P < 0.0001), respectively. Systemic and portal plasma TIMP‐1 levels were significantly higher in those with metastatic disease compared with those with localized disease (P=0.0248 and P=0.0382). Elevated levels of TIMP‐1 in systemic blood were seen in those with muscle‐invading tumours compared with more superficial lesions (P=0.0349). Plasma MMP‐9 levels did not correlate with clinicopathological features.ConclusionTIMP‐1 and MMP‐9 levels were significantly elevated in the plasma of patients with colorectal cancer. Metastatic disease is associated with significantly higher plasma TIMP‐1 than is localized disease. Sampling of portal blood is of no additional benefit when measuring MMP‐9 enzyme levels in colorectal cancer.