bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ecology of a diplozoon parasite on the gills of the African cyprinid Barbus neumayeri
Authors: Chapman Lauren J. , Lanciani Carmine A. , Chapman Colin A. 
Published: March 2003

AbstractIn oxygen‐deficient waters, the difficulties of oxygen uptake in gill parasites and their fish hosts may influence host and parasite densities, site selection by the parasite, and effects of the parasite on host condition. This study quantified the prevalence and intensity of the gill monogenean Neodiplozoon polycotyleus in the African cyprinid fish Barbus neumayeri from an intermittent forest stream in western Uganda. Oxygen levels were low in the stream over the 12‐month study, averaging only 2.5 mg litre−1 (monthly range = 1.2–4.3 mg litre−1). However, parasite prevalence was high (47.2%), suggesting high tolerance to low oxygen in N. polycotyleus. The prevalence of parasites varied with host body size, with the highest frequency of occurrence in the middle size classes. Prevalence also varied over the year; seasonal peaks of rainfall coincided with a lower frequency of N. polycotyleus. The significantly nonrandom frequency distribution of parasites among hosts suggests regulation of parasite numbers. Of the hosts infected, 37.1% harboured one N. polycotyleus parasite, and 62.9% harboured two parasites. No fish were infected with more than two diplozoons. There was evidence for strong site specificity by N. polycotyleus within hosts; 77.7% of the parasites were located on the filaments of the second gill arch, which may relate to increased oxygen availability. In addition, only one of the 178 infected fish had more than one parasite on one side of the branchial basket. Although N. polycotyleus is undoubtedly parasitic, we found no evidence of a negative parasitic effect on the condition or reproductive status of B. neumayeri.
Habitat utilization and home range of the redwing francolin, Francolinus levaillantii, in highland grasslands, Mpumalanga province, South Africa
Authors: Jansen R. , Little R. M. , Crowe T. M. 
Published: March 2003

AbstractThe effects of intensive commercial livestock farming on the distribution and habitat use of the redwing francolin, Francolinus levaillantii, was investigated to identify habitat constraints that may contribute towards the observed decline of this species on livestock farms. Data on the size, placement of the home ranges and compositional habitat use from ten radio‐tracked individuals, five in commercially grazed (and frequently burned) and five in protected (and infrequently burned) highland grasslands, was collated to determine habitat preferences. Mean home range size within protected and grazed grassland study sites were similar and ranged between 7.6 and 15.4 hectares. However, habitat use by groups in grazed grasslands was restricted to areas of greater cover and food availability. Group sizes were significantly larger in protected (mean 3.77, n = 111 coveys) than in grazed and frequently burned grassland (mean = 2.96, n = 135 coveys). Smaller coveys in grazed habitats had smaller home ranges and were further spaced from one another. It is therefore suggested that habitat degradation, through excessive defoliation of the grassland from heavy grazing and frequent burning, both fragments francolin subpopulations and reduces the ecological availability of suitable habitat. Thus, undermining the metapopulation structure of the redwing francolin in these commercially grazed grasslands.
Demography of a West African kob (Kobus kob kob) population
Authors: Fischer Frauke , Linsenmair K. Eduard 
Published: March 2003

AbstractThe kob (Kobus kob kob) population studied in the Comoé National Park, Ivory Coast, suffered unsustainable losses to poaching before and during the investigation. This in turn did not only lead to low densities but also changed the population composition, resulting in a strong female bias in all age classes except juveniles. The relative rarity of adult males probably had negative effects on the population recruitment. Although mating occurred throughout the year and birth intervals were short, at least in some females, annual birth‐rate was low compared to earlier studies in the same area. Effective conservation measures are urgently needed to ensure the future existence of the studied population.
An investigation into the composition, complexity and functioning of snake communities in the mangroves of south‐eastern Nigeria
Authors: Luiselli Luca , Akani Godfrey C. 
Published: March 2003

AbstractThe structure of the snake community was studied between 1996 and 2000 on a transect in the mangrove ecological zone of southern Nigeria, West Africa. In three major habitats, both taxonomical diversity and frequency of observations in relation to sampling effort were investigated. In general terms, the complexity of the snake community appeared less than in other habitats of the same geographic region (i.e. swamp forest and forest–plantation mosaics). In fact, only eighteen species were recorded, whereas 43 species are known to inhabit neighbouring habitats. A Principal Component Analysis allowed arrangement of the various species into two main groups in relation to the habitats of capture: (1) a group of species of rainforest biota (i.e. Toxicodryas blandingii, Thelotornis kirtlandii, Thrasops flavigularis, Rhamnophis aethiopissa, Gastropyxis smaragdina, Grayia smythii, Pseudohaje goldii, Python sebae), and (2) a group of species that, at least in Niger Delta, are typically linked to altered habitats, including derived savannas, plantations and suburbia (i.e. Psammophis cf. phillipsi, Philothamnus cf. nitidus, Hapsidophrys lineatus, Crotaphopeltis hotamboeia, Boaedon lineatus, Naja nigricollis, Python regius). The community structure in terms of food habits and body sizes appeared similar to those of other snake assemblages from different habitats of southern Nigeria. The conservation implications of our results are also discussed.
High molecular protein of Helicobacter pylori responsible for inhibition of ornithine decarboxylase activity of human gastric cultured cells
Authors: Takashima T. , Fujiwara Y. , Watanabe T. , Tominaga K. , Oshitani N. , Higuchi K. , Matsumoto T. , Arakawa T. , Hasuma T. , Yano Y. , Otani S. 
Published: March 2003

Background:Ornithine decarboxylase (ODC), a rate‐limiting enzyme of polyamine biosynthesis, mediates epithelial cell proliferation and plays a critical role in the optimal repair of gastric mucosal damage. Several studies have shown that Helicobacter pylori inhibits the growth and proliferation of gastric cells in vitro.Aim:To test whether H. pylori extract affects ODC mRNA expression and its enzyme activity in gastric cells and to examine the partial characterization of the molecule responsible for this effect.Methods:Human gastric cells (MKN‐45) were used. Bacterial extracts from various E. coli or H. pylori strains, namely (1) cagA+, vacA+, CagA+, VacA+; (2) cagA+, vacA+, CagA+ VacA–; or (3) cagA–, vacA+, CagA–, VacA– were added to the cells. Cell proliferation was assessed by [3H]‐thymidine incorporation, viability by MTT assay and LDH release test, ODC enzyme activity by 14CO2 counts from L‐[114C]ornithine, and ODC mRNA by Northern blotting.Results: H. pylori and E. coli extract did not affect viability of gastric cells. H. pylori extract, especially extracts containing a protein greater than 50 kDa, significantly inhibited proliferation and ODC activity of gastric cells while E. coli extract had no effect. Inhibition of ODC activity was found in extracts of all H. pylori strains, irrespective of CagA and VacA protein expression. Serum stimulation induces an increase in ODC mRNA while H. pylori extract did not affect ODC mRNA expression.Conclusion:High molecular weight (greater than 50 kDa) proteins of H. pylori extract without CagA or VacA protein inhibited proliferation and ODC activity of human gastric cells, but did not affect ODC mRNA expression, suggesting that inhibition of ODC activity is regulated at the post‐transcriptional level.
Gastric ulcerogenic responses following barrier disruption in knockout mice lacking prostaglandin EP1 receptors
Authors: Takeuchi K. , Ogawa Y. , Kagawa S. , Ukawa H. 
Published: March 2003

Background/aims:Endogenous prostaglandins (PGs) are considered to play a pivotal role in maintaining the mucosal integrity of the stomach after injury. In the present study, we evaluated the mucosal ulcerogenic and mucosal blood flow (GMBF) responses in the stomach after damage by taurocholate (TC) in knockout mice lacking EP1 or EP3 receptors.Methods:Under urethane anaesthesia, a mouse stomach was mounted in an ex vivo chamber, exposed to 20 mmol/L TC for 20 min and treated with 20 mmol/L HCl before and after TC. GMBF was measured with a laser Doppler flowmeter.Results:Mucosal exposure to TC in wild‐type mice caused a marked decrease in potential difference (PD), followed by an increase in H+ loss and GMBF. The decreased PD was gradually normalized after removal of TC from the chamber, with minimal damage in the mucosa 1 h after TC treatment. This hyperaemic response was inhibited by indomethacin, resulting in severe lesions in the mucosa without any change in PD or H+ loss. None of these responses induced by TC were altered in EP3−/− mice. However, in mice lacking EP1 receptors, TC treatment did not increase GMBF, despite causing PD reduction and acid loss, and resulted in severe damage in the mucosa. These responses were closely similar to those observed in animals pretreated with ONO‐8711, a EP1 receptor antagonist. Mucosal PGE2 content was significantly increased after TC, similarly in all groups of mice.Conclusion:These results confirm a mediator role for PGE2 in gastric hyperaemic response following mucosal exposure to TC and suggest that endogenous PGs may contribute to maintaining mucosal integrity after barrier disruption, mainly through activation of the EP1 receptor subtype.
Up‐regulation of COX‐2 by inhibition of COX‐1 in the rat: a key to NSAID‐induced gastric injury
Authors: Tanaka A. , Araki H. , Hase S. , Komoike Y. , Takeuchi K. 
Published: March 2003

Background:A recent study demonstrated that inhibition of both cyclooxygenase (COX)‐1 and COX‐2 is required for the development of nonsteroidal anti‐inflammatory drug (NSAID)‐induced gastric lesions. However, the role of COX‐1 or COX‐2 inhibition in the pathogenisis of these lesions remains unclear.Aim:To examine the gastric ulcerogenic properties of selective COX‐1 and COX‐2 inhibitors in rats and to investigate further the relationship of COX inhibition to various events involved in the process of NSAID‐induced gastric lesions.Methods:Animals were given various COX inhibitors p.o., either alone or in combination, and killed 8 h later. Under the treatment, gastric damage, prostaglandin (PG) E2 content, mucosal permeability, myeloperoxidase (MPO) activity as well as gastric motility were examined.Results:The nonselective COX inhibitor indomethacin inhibited PGE2 production, enhanced gastric motility, and provoked severe lesions in the stomach, with an increase in mucosal permeability and MPO activity. In contrast, the selective COX‐2 inhibitor rofecoxib did not induce any damage in the stomach and had no effect on mucosal PGE2 content. Similarly, the selective COX‐1 inhibitor SC‐560 also caused no gastric damage, despite inhibiting PGE2 production. The combined administration of SC‐560 and rofecoxib, however, provoked gross damage in the gastric mucosa, in a dose‐dependent manner for each drug. SC‐560, but not rofecoxib, caused marked gastric hypermotility and an increase in mucosal permeability, although an increase in MPO activity was observed only when rofecoxib was coadministered. The normal gastric mucosa expressed COX‐1 mRNA and not COX‐2 mRNA, but COX‐2 mRNA was expressed in the stomach after administration of SC‐560 as well as indomethacin but not rofecoxib.Conclusion:These results suggest that the gastric ulcerogenic properties of NSAIDs are not accounted for solely by COX‐1 inhibition, but require the inhibition of both COX‐1 and COX‐2. The inhibition of COX‐1 up‐ regulates COX‐2 expression, and COX‐2/PGs may, in turn, counteract the deleterious affects of gastric hypermotility due to COX‐1 inhibition.
Role of elastase and active oxygen species in gastric mucosal injury induced by aspirin administration in Helicobacter pylori‐infected Mongolian gerbils
Authors: Yoshida N. , Sugimoto N. , Ochiai J. , Nakamura Y. , Ichikawa H. , Naito Y. , Yoshikawa T. 
Published: March 2003

Background: H. pylori infection potentiates aspirin‐induced gastric mucosal injury by mechanisms that include accumulation of activated neutrophils.Aim:To determine the role of elastase and active oxygen species (AOS) produced by activated neutrophils in the gastric mucosal injury induced by administration of acidified aspirin to H. pylori‐infected Mongolian gerbils.Methods: H. pylori ATCC43504 culture broth was administered by oral gavage to male Mongolian gerbils at 7 weeks of age. After 4 weeks, acidified aspirin (400 mg/kg) was administered orally, and 3 h later, the total area of gastric erosions, myeloperoxidase (MPO) activity (an index of neutrophil accumulation), thiobarbituric acid‐reactive substances (TBARS, an index of lipid peroxidation), and KC/GRO (a chemo‐attractive cytokine in rodents) were measured in gastric mucosa. To determine the role of elastase or AOS derived from neutrophils in these circumstances, ONO‐5046 (an elastase inhibitor), a combination of superoxide dismutase (SOD) and catalase (scavengers of AOS), and polaprezinc (an anti‐ulcer agent with anti‐inflammatory effects) were administered before aspirin.Results:ONO‐5046 inhibited the increase in gastric erosions and mucosal TBARS induced by administration of aspirin to H. pylori‐infected gerbils, but not the increases in MPO activity or KC/GRO contents. A combination of SOD and catalase or polaprezinc significantly reduced gastric erosions, TBARS concentrations, MPO activity and KC/GRO concentration.Conclusions:These results suggest that neutrophil‐derived‐elastase and ‐oxidants play an important role in the gastric mucosal injury induced by administration of aspirin to H. pylori‐infected gerbils.
Screening of gene expression profiles in gastric epithelial cells induced by Helicobacter pylori using microarray analysis
Authors: Sepulveda A. R. , Tao H. , Carloni E. , Sepulveda J. , Graham D. Y. , Peterson L. E. 
Published: March 2003

Background: H. pylori infection is a major risk factor in gastric cancer development. The availability of cDNA microarrays creates the unprecedented opportunity to examine simultaneously dynamic changes of multiple pathways affected by H. pylori infection.Aim:In this study we examined broad patterns of gene expression induced by H. pylori in the gastric cancer cell line 1739‐CRL AGS cells in culture using the U95A microarray.Methods: H. pylori were cocultured with AGS cells for 4, 12, 24 and 48 h. Total RNA was extracted and after labelling was used for detection of genes represented in the human U95A microarray set. Data analyses were performed using GeneChip and CLUSFAVOR software.Results:Nearly 6000 genes present in the array were expressed by AGS cells. We report approximately 200 genes that showed the most marked changes. Our studies confirm the up‐regulation of c‐jun, jun‐B, c‐fos and cyclin D1 by H. pylori. We report for the first time the induction of the serine threonine kinase pim‐1 and ATF3 by H. pylori infection of AGS cells.Conclusions:In this microarray analysis of gene expression induced by H. pylori in gastric epithelial cells, we identified a large number of unsuspected genes affected by H. pylori. Further, we show that unsupervised hierarchical cluster analysis can provide useful insight into the possible contribution of genes in specific pathways, based on their profile of expression.
Helicobacter pylori and clinical risks—focus on gastro‐oesophageal reflux disease
Authors: Malfertheiner P. , O'Connor H. J. , Genta R. M. , Unge P. , Axon A. T. R. 
Published: March 2003

Helicobacter pylori is a gastric pathogen that is a major cause of peptic ulcer disease, has a role in mucosa‐associated lymphoid tissue (MALT) lymphoma and is associated with gastric cancer. Yet, in a large proportion of the human population, H. pylori infection has no apparent adverse clinical consequences. Furthermore, recent research suggests that H. pylori may even confer protection against gastroesophageal reflux disease.The conflicting evidence surrounding H. pylori infection was discussed at a sponsored symposium in Helsinki, introduced by Professor P. Malfertheiner, with papers presented by Dr H. J. O'Connor, Professor R. M. Genta, Dr P. Unge and Professor A. T. R. Axon. Emerging epidemiological and retrospective evidence suggests that the presence of H. pylori infection may provide some protection against gastroesophageal reflux disease, but there is other evidence that shows no benefit of H. pylori for the protection of the oesophagus. It was felt that prospective, multicentre studies are needed to explore the H. pylori–gastroesophageal disease relationship further, to avoid confusing potential benefits with known risks.Following the symposium, a discussion on the relative risks and benefits for H. pylori eradication was provided by Professor Axon and Professor Blaser.Eradication of H. pylori has been recommended in a series of management guidelines issued by consensus groups. However, accurate estimates of the relative risks and benefits of H. pylori infection in the general population, as well as in specific patient groups, is essential in order to develop a management strategy.
After gastritis – an imaginary journey into a Helicobacter‐free world
Authors: Genta R. M. 
Published: March 2003

SummaryThis article explores the consequences of the world‐wide trend that may result – at different times for different populations – in the disappearance of Helicobacter pylori and gastritis. After a brief historical introduction, some of the factors that contribute to the decrease in the prevalence of H. pylori are presented. The most apparent results of this trend in the industrialized world have been a decrease in the incidence of peptic ulcer and distal gastric adenocarcinoma. However, some other conditions of the upper digestive tract, such as acid reflux disease and adenocarcinoma of the cardio‐oesophageal junction have been increasing. This simultaneous increase has led to the speculation that it may be causally related to the decreased prevalence of gastritis, and currents of thought supporting a laissez faire attitude with regards to H. pylori infection have developed. If these trends continue, future research aimed at understanding the pathogenesis of H. pylori‐related conditions, including gastric carcinogenesis, will hinge on access to populations in which H. pylori is still highly prevalent, and on further refinement of the recently introduced Mongolian gerbil model.
Cost‐effectiveness of different GERD management strategies
Authors: Vakil N. 
Published: March 2003

SummaryRecent data on gastro‐oesophageal reflux disease management strategies suggest that the indirect costs of reflux disease are high, and that inadequate treatment is associated with significant out‐patient costs for patients. Long‐term management strategies now focus on discontinuous therapy for some subgroups of patients. On‐demand therapy is particularly attractive for patients who have no mucosal disease.
Ulcerative colitis – surgical indications and treatment
Authors: Nicholls R. J. 
Published: March 2003

SummaryThe indication for surgery is a balance between the severity of the disease despite full medical treatment and the potential disadvantages of surgery. The decision requires cooperation between gastroenterologist and surgeon.Colectomy with ileostomy and preservation of the rectum in the emergency setting is the accepted procedure and can rapidly restore the patient to normal health allowing withdrawal of anti‐inflammatory medication. After recovery all surgical possibilities are then open for the future.The elective indications for surgery include failure of medical treatment, retardation of growth in a child or adolescent and neoplastic transformation. The choice of operation includes conventional proctocolectomy, restorative proctocolectomy (RPC) and colectomy with ileo‐rectal anastomosis. Each has relative advantages and disadvantages. RPC is the commonest procedure. It offers a satisfactory outcome in 70–90% of patients with a cumulative failure rate of 10–15% over a 10 year period.Causes of failure include sepsis (50%), dysfunction (30%) and pouchitis (10%). In selected cases salvage surgery to avoid failure can be successful with rates of around 70% for outlet obstruction and fistulation and 50% for pelvic sepsis.
The management of refractory Crohn's disease
Authors: Rizzello F. , Gionchetti P. , Venturi A. , Morselli C. , Campieri M. 
Published: March 2003

SummaryRefractoriness to conventional therapy is a common and intriguing problem in Crohn's disease patients. At the present time there is no agreement on its definition and several mechanisms are involved in its determination. Immunosuppressors, such as azathioprine (AZA), 6‐mercaptopurine (6MP) and methotrexate (MTX) are effective drugs for controlling the inflammatory process and avoid chronic glucocorticosteroid treatment and its related related side‐effects. Recently, the introduction of tumour necrosis factor antibodies (infliximab) has dramatically changed the natural history of Crohn's disease and its therapeutic approach. Several studies have determined the efficacy, mechanisms and safety of infliximab. However, this molecular approach has also left several questions unanswered about the mechanisms of refractoriness, possible concomitant treatments and long‐term safety and efficacy.
Review article: albumin as a drug—biological effects of albumin unrelated to oncotic pressure
Authors: Evans T. W. 
Published: March 2003

SummaryAlbumin is the main determinant of plasma oncotic pressure and it plays a pivotal role in modulating the distribution of fluids between compartments. Moreover, it has many other biological properties which may be important not only for its physiological actions but also for its therapeutic effects. Among the non‐oncotic properties are its capacity of molecule transportation and free radical scavenging, its ability to modulate capillar permeability, neutrophil adhesion and activation and its haemostatic effects. The following article reviews these biological effects as well as its structure, synthesis, catabolism and distribution.
Meta‐analysis of somatostatin, octreotide and gabexate mesilate in the therapy of acute pancreatitis
Authors: Andriulli  , Leandro  , Clemente  , Festa  , Caruso  , Annese  , Lezzi  , Lichino  , Bruno  , Perri  
Published: March 2003

Background:Autodigestion of the pancreas, secondary to the activation of digestive enzymes, is the pathogenetic mechanism of acute pancreatitis (AP).Aim:Clinical trials in which somatostatin (SS), octreotide (OCT) and gabexate mesilate (FOY) were used to treat patients with AP, were submitted to a meta‐analytical evaluation. Five end‐points were evaluated: early and overall mortality, patients with complications, complication rate, and patients who needed surgery.Results:In mild AP, no agent proved of value. In severe AP, both SS and OCT were beneficial in improving the overall mortality: the odds ratios (OR) were, respectively, 0.36 (95% CI: 0.20–0.64, P = 0.001) and 0.57 (95% CI: 0.35–0.88, P = 0.006). FOY had no effect on either early or overall mortality, but was effective in improving complication rate (OR = 0.70, 95% CI: 0.56–0.88, P = 0.02), number of patients with complications (OR = 0.61, 95% CI: 0.41–0.91, P = 0.01), and number of cases submitted to surgery (OR = 0.60, 95% CI: 0.39–0.92, P = 0.01). SS and OCT had no effect on these latter outcomes.Conclusions:Antisecretory agents, such as SS and OCT, are able to reduce mortality without affecting complications, whereas antiproteases, such as FOY, have no effect on mortality but do reduce complications. A trial exploring the efficacy of combining antisecretory agents with antiproteases would be of great benefit in patients with severe AP.