bluuebunny/crossref_metadata_2025 huggingface dataset:
Amphibian Distributions in a Landscape of Forests and Agriculture: an Examination of Landscape Composition and Conf iguration
Authors: Guerry Anne D. , Hunter Malcolm L.
Published: March 2003

Abstract:Landscapes can be described by two essential features: the composition and spatial arrangement of patches. We considered the roles of these basic landscape descriptors by examining how the occurrence of nine amphibian species in breeding ponds was associated with the area of forested habitat and the proximity of ponds to forested habitat. We used visual and call surveys to compare the composition of amphibian assemblages in 116 ponds adjacent to or separated from forest and surrounded by different amounts of forested land. The area of forest and pond adjacency to forest were not associated (   t= −0.13,nisolated= 64,nconnected= 52,p= 0.21), which means these factors can manifest their effects separately. We used logistic regression to test predictions about associations between each species and forest area and to test for associations with pond‐forest adjacency. Seven of nine species were associated with forest area. Wood frogs (   Rana sylvatica), green frogs (  Rana clamitans), eastern newts (  Notopthalmus viridescens), spotted salamanders (Ambystoma maculatum), and salamanders of the blue‐spotted/Jefferson's complex (Ambystoma laterale/A. jeffersonianum) were more likely to occupy ponds in more forested areas, whereas leopard frogs (  Rana pipiens) and American toads (  Bufo americanus) were negatively associated with forest area. Three species were associated with pond‐forest adjacency. Spotted salamanders and salamanders of the blue‐spotted/Jefferson's complex were more likely to occupy ponds that were adjacent to forest. In areas with little forest, leopard frogs were more likely to occur in adjacent ponds, but the reverse was true for areas with extensive forests. Our results suggest that the composition of the landscape surrounding breeding ponds is associated with the likelihood of occurrence of most of the species examined and that landscape configuration is also important for a smaller subset of species.
Putting Science in its Place
Authors: Freyfogle Eric T. , Newton Julianne Lutz
Published: March 2003

Abstract: Science and policy are both relevant to managing land. How they fit together is best understood by viewing land management as a process and by beginning the inquiry from and with that process, drawing distinctions between issues of substance and process and between the functions of describing nature and evaluating it normatively. This process‐based approach and these two distinctions help isolate and clarify the various proper roles of science in the overall land‐management equation. They also clarify (1) when nature can be said to possess intrinsic value; (2) why it is proper for conservation biologists to base their work on normative goals as long as they make it clear what they are doing; and (3) why arguments surrounding ecosystem management, which should focus on competing policy visions, are often diverted into less fruitful arguments about science and process. A process‐based approach that employs our distinctions is particularly useful, we argue, in showing why confusion arises so easily when science‐based terms such as ecological integrity are used not just for science purposes but as normative land‐management goals. Using science terms in this way can strengthen the conservation cause by expanding the influence of scientists, but dangers lurk in the practice, including dangers to the integrity of science as such. On balance, a goal less overtly tied to science—such as land health—offers a better option for land management.
Ecoregions in Context: a Critique with Special Reference to Indonesia
Authors: Jepson Paul , Whittaker Robert J.
Published: March 2003

Abstract:World Wildlife Fund–United States (  WWF  ) is promoting an ecoregional framework internationally as a new hierarchical approach to organizing and prioritizing conservation efforts. We assessed WWF ecoregions against existing frameworks: (1) the Dasmann‐Udvardy (   World Conservation Union [IUCN] ) Biogeographical Representation Framework, (2) the Bailey Ecoregional Framework ( U.S. Forest Service), and (3) the hotspot approach, as exemplified by the BirdLife Endemic Bird Area Approach and the WWF–IUCN Centres of Plant Diversity Program. We examined the genealogy of the schemes from three perspectives: methodological explicitness, transparency and repeatability, and whether the WWF–ecoregions system improves on existing schemes. We considered Indonesia as a case study and assessed the efficacy of each system in the Indonesian context. The existing planning frameworks achieved their objective; in general had explicit, transparent, and repeatable methods; and, in the case of the Dasmann‐Udvardy system, attained an institutional reality in Indonesia. The central purpose of the WWF–ecoregions framework is the same as the 25‐year‐old Dasmann‐Udvardy system, and at the coarsest spatial scales it relies on similar spatial delineators (  biomes and faunal regions). The WWF methodology, however, employs a gestalt approach to defining ecoregion boundaries. In the Indonesian context the resulting map appears problematic both in terms of the underlying rationale of the ecoregion approach and in terms of apparent conflict with preexisting protected‐area design. We suggest, insofar as refined planning frameworks are needed, that an alternative route that builds on rather than competes with existing approaches would be to combine at the mesoscale the landform delineators that characterize the Bailey ecoregion system with the existing macroscale ecoclimatic and biogeographic delineators of the Dasmann‐Udvardy system. We question the investment in developing and promoting the WWF–ecoregion scheme in Indonesia when the existing Dasmann‐Udvardy system, used in conjunction with hotspot studies, provides a seemingly adequate system and when the reserve system itself is under considerable pressure.
Using Decline in Bird Populations to Identify Needs for Conservation Action
Authors: Dunn Erica H.
Published: March 2003

Abstract:A large decline in population size is sometimes considered sufficient indication that a species merits conservation interest. One organization categorizes as critically endangered any species whose populations decline by 80% over 10 years, whereas others assign importance to species declining 50% over 25 years. Using these and additional conservation‐alert categories, I determined how many of over 200 bird species that breed in Canada qualified for each category, based on population trends from the North American Breeding Bird Survey. The majority of qualifying species were not candidates for immediate intervention to halt or reverse declines. Moreover, species assigned to alert categories based on 5‐ and 10‐year trends for past time periods frequently had positive trends in the subsequent decade. Results indicate that population decline should not be used to identify species at risk or as a basis for conservation action without detailed evaluation of the trend data and other characteristics of the species. However, assigning species to alert categories is a useful step in identifying species that may deserve conservation attention of some kind (including better monitoring and research as well as direct intervention). Evaluation of trend quality and persistence is an important step in determining the most appropriate action. Deciding when to recommend intervention will be the most problematic for species that are still relatively common and widespread, and there is a need for development of species‐specific population thresholds that would be appropriate for triggering such action.
Social Influences on Conservation: Lessons from U.S. Recovery Programs for Marine Mammals
Authors: Wallace Richard L.
Published: March 2003

Abstract:Marine mammal recovery programs authorized by the U.S. Marine Mammal Protection Act and the U.S. Endangered Species Act face many challenges. In addition to biological uncertainty, social, organizational, and other conditions influence the decision‐making behavior of program participants. From 1996 to 1999, I analyzed the decision‐making behavior of participants in five marine mammal recovery programs. Based on a literature review and interviews with 90 program participants, I identified, described, and analyzed the principal influences on participant behavior. Results indicate that decision‐making and participant interactions are influenced strongly, and in some cases predominantly, by social factors such as leadership characteristics, communication, teamwork, the presence or absence of evaluation, organizational culture, and program participants' ideologies. These findings indicate the need to improve marine mammal recovery programs through training, evaluation, and the development of prototype programs that incorporate and explicitly apply social factors to problem solving and then use their experience as a model for future programs.
Willingness To Pay: A Method For Measuring Preferences For Maternity Care?
Authors: Donaldson Cam , Hundley Vanora , Mapp Tracy
Published: March 2003

Background:

The aim of this study was to assess the feasibility of the use of “willingness to pay” as a measure of the benefits of intrapartum care.

Methods:

A questionnaire was mailed to 150 pregnant women booking at Aberdeen Maternity Hospital in the northeast of Scotland, giving information on options for intrapartum care compiled from a recent randomized trial of care in a midwife‐managed delivery unit versus care in a consultant‐led labor word. Women were asked which type of care they preferred and what would be their maximum willingness to pay for their preferred option. Data were also collected on demographic and clinical characteristics.

Results:

Most women (55%) expressed a preference for care in a midwives unit. However, strength of preference, as reflected in willingness to pay, was greater among those in the smaller group, who expressed a preference for care in a consultant‐led labor ward. The willingness‐to‐pay results were not associated with ability to pay.

Conclusions:

These data should be used together with cost data to decide on provision of care. Given the strength of preference of the minority group, and if the cost implications are not too great, a flexible service that takes account of women's wishes should be provided, even if this goes against the trend for care of those at low risk. By analyzing choice of care by income groups and social class groupings, it is possible to examine whether willingness‐to‐pay results are associated with indicators of ability to pay. In this case, they were not. Willingness to pay has an advantage in allowing respondents to account for more than just health gain when valuing different types of care. (BIRTH 25:1, March 1998)
Concepts and Controversies in the Management of Group B Streptococcus During Pregnancy
Authors: Glantz J. Christopher , Kedley Karen E.
Published: March 2003

Background:

Group B beta‐hemolytic streptococcus colonizes 20 percent of pregnant women. Intrapartum fetal colonization leads to invasive disease in 1 to 2 infants of every 1000 births in the United States, and has a mortality of approximately 6 percent. Several protocols using intrapartum chemoprophylaxis have been devised to improve management of the disease, but confusion continues about details and implementation. This review examined the clinical issues, current management protocols, and advantages and disadvantages of these protocols for group B streptococcus.

Methods:

We reviewed the literature and described the epidemiology, detection methods, risk factors, neonatal disease potential of group B streptococcus, and the historical development of management protocols. Two current alternatives, the American College of Obstetricians and Gynecologists' risk‐based protocol and the Centers for Disease Control and Prevention's screening‐based protocol, are described and compared.

Results:

The risk‐based protocol does not entail antepartum screening, but treats women with certain risk factors during labor. The screening‐based protocol includes cultures at 35 to 37 weeks' gestation, and offers intrapartum prophylaxis to all women with positive cultures. Uncultured women with risk factors are treated. Both protocols involve high rates of intrapartum antibiotic use and both may significantly lower rates of neonatal group B streptococcus sepsis (screening‐based more than risk‐based for both). The risk‐based approach is simpler than the screening‐based approach.

Conclusions:

Practitioners should select one of the two protocols and use it consistently. The differences in efficacy are small; a practitioner may not see a difference in outcomes over the course of his or her career, although more antibiotics will be administered using the screening‐based approach. (BIRTH 25:1, March, 1998)
Pregnancy Outcome After Previous Stillbirth Resulting from Causes Other Than Maternal Conditions and Fetal Abnormalities
Authors: Heinonen Seppo , Kirkinen Pertti
Published: March 2003

Background:
An adequate fetomaternal circulatory system may be compromised by a variety of disturbances leading to stillbirth. The purpose of this study was to assess subsequent pregnancy outcome in women with a history of stillbirth as a result of causes other than maternal conditions and fetal abnormalities.
Methods:
Ninety‐two deliveries after stillbirth were identified among 11,910 deliveries of parous women recorded in the birth registry at Kuopio, Finland. Using logistic regression, pregnancy outcome measures were compared with those of a parous healthy obstetric population (n= 11,818).Results:Women with a history of stillbirth as a result of causes other than maternal conditions and fetal abnormalities were older than their unaffected controls (32.4 yr vs 30.3 yr). Stillbirth in an earlier pregnancy was associated with a significantly higher (p < 0.001) frequency of placental abruption in subsequent pregnancy (5.4% vs 0.7%). A history of stillbirth was predictive of preterm delivery (OR = 2.25) and low‐birthweight infants (OR = 2.70). No recurrence was reported.Conclusions:Pregnancy with a history of stillbirth as a result of causes other than maternal conditions and fetal abnormalities is a moderate risk state, with prematurity and low‐birthweight rates somewhat higher than those in the general population. The overall probability of a favorable outcome is good. These findings may be useful in counseling pregnant women with a history of stillbirth.
Breastfeeding Duration in a Multiethnic Population in Hawaii
Authors: Novotny Rachel , Hla Mya Moe , Kieffer Edith C , Park Chai‐Bin , Mor Joanne , Thiele Maureen
Published: March 2003

Background:The increasing ethnic diversity in the United States necessitates a study of variations in infant feeding patterns among ethnic groups. This study was conducted as part of Hawaii's surveillance system to identify infant feeding patterns in Hawaii; specifically, to identify factors influencing duration of breastfeeding among ethnically diverse mothers.Methods:All women who delivered an infant in Hawaii between January 1 and March 31, 1989, were mailed surveys 14 to 19 months after delivery. Fifty‐one percent (n= 2011) of women responded, of whom 1574 (78%) did some breastfeeding and are included in the analysis of prediction of weaning (cessation of breastfeeding). Cox regression (survival) analysis was used to predict weaning.Results:The median duration of breastfeeding was 150 days; 45 percent of infants were still breastfeeding at age 6 months and 16 percent at age 1 year. Factors associated with early weaning were Japanese ethnicity; mother born in a country other than the United States, Japan, or the Philippines; first language other than English, or two languages at home; employed full‐time outside the home; introduced formula or fruit before age 6 months; received formula from the WIC program; and stopped breastfeeding for convenience, breast problems, problems getting breastfeeding started, insufficient milk, baby refusing the breast, and a sick baby. Factors associated with late weaning were older maternal age; college education; living on a rural island; previous breastfeeding experience; helpful breastfeeding advice from family or friends; receiving WIC for breastfeeding mothers; introducing the cup before age 6 months; and not giving fruit to the baby.Conclusion:In Hawaii, programs that address how and when to introduce foods, use of formula, and management of outside employment and breastfeeding should be made available to those groups of women at risk for early weaning to lengthen their duration of breastfeeding.
Partner Support and Pregnancy Wantedness
Authors: Kroelinger Charlan D , Oths Kathryn S
Published: March 2003

Background:Women who experience unwanted pregnancy are at a greater risk of complicated pregnancy outcomes, and their children are more likely to experience physical or psychological problems in infancy, than those women with wanted pregnancies. The objective of this research was to explain the impact of a partner on women's decisions to want or not want their pregnancies.Methods:A primary study subsample of 349 clinical interviews of pregnant women comprised the quantitative portion of the analysis, with a secondary study subsample of 20 in‐depth qualitative interviews of pregnant women complementing the statistical findings. Both samples included adult women (at least age 20 yr) of different ethnic groups who received Medicaid for their pregnancies and were in their first or early second trimester of pregnancy. Chi‐square,ttests, and logistic regression were used for statistical analyses.Results:A partner's stability, status, feelings toward pregnancy, and level of dependability and support all had a significant influence on women's experiences of unwanted pregnancy. Variables including use of contraception (OR = 3.3), women's ethnicity (OR = 1.9), partner's feelings about pregnancy (OR = 2.0), amount of social support (OR = 1.2), and mother's instrumental support (OR = 0.85) all affected women's perceptions of wanting the pregnancy. These results were used to create a model of unwanted pregnancy, beginning before conception and ending with either termination of pregnancy or initiation of prenatal care.Conclusions:The support and concern of a partner during pregnancy can have positive consequences for a mother's desire to carry out the pregnancy. To increase their commitment to the pregnancy and childbirth, partners should be included more in the prenatal care process.
An Alternative Non‐Macrolide, Non‐Imidazole Treatment Regimen for Curing Helicobacter pylori and Duodenal Ulcers: Ranitidine Bismuth Citrate Plus Amoxicillin
Authors: Graham David Y. , Breiter Jeffrey R. , Ciociola Arthur A. , Sykes Deborah L. , McSorley David J. , The Rbc Pylori H. , Group Study
Published: March 2003

Background. Because patients who fail to be cured of H. pylori infection following macrolide or imidazole therapy are difficult to treat, there is a clear need for a reasonably effective and simple second‐line treatment regimen. The purpose of these two studies was to evaluate the efficacy of ranitidine bismuth citrate (RBC) plus amoxicillin for the cure of H. pylori infection and for healing duodenal ulcers and preventing ulcer relapse.

Materials and Methods. Two identically designed randomized, double‐blind, double‐dummy studies were conducted in patients with an H. pylori‐associated duodenal ulcer. Patients were treated with either RBC 400 mg bid for 4 weeks plus amoxicillin 500 mg qid for 2 weeks, RBC 400 mg bid for 4 weeks and placebo qid for 2 weeks, placebo bid for 4 weeks and amoxicillin 500 mg qid for 2 weeks, or placebo bid for 4 weeks and placebo qid for 2 weeks. Patients with healed ulcers after 4 weeks of treatment were eligible for entry into a 24‐week observation phase for the assessment of H. pylori status (culture, histology, and CLOtestTM) and ulcer relapse.

Results. A total of 229 patients with confirmed H. pylori infection at baseline were evaluated. Of these, 132 whose ulcers had healed entered the 24‐week posttreatment observation phase. The combination of RBC plus amoxicillin resulted in higher H. pylori cure rates (55%) and higher duodenal ulcer healing (74%) than did either treatment alone. All treatments were well tolerated.

Conclusions. The combination of ranitidine bismuth citrate plus amoxicillin cures H. pylori infection in more than half of the patients treated. This treatment regimen shows promise as the basis for future non‐macrolide, non‐imidazole triple therapy regimens for curing H. pylori infection. Such regimens may be appropriate second‐line treatment for patients who are resistant to or who are unable to tolerate macrolide‐ or imidazole‐containing therapies.
How Do Practicing Clinicians Manage Helicobacter pylori‐Related Gastrointestinal Diseases in Germany? A Survey of Gastroenterologists and Family Practitioners
Authors: Breuer Thomas , Sudhop Thomas , Goodman Karen J. , Graham David Y. , Malfertheiner Peter
Published: March 2003

Background.

Since the bacterium H. pylori was identified in 1982, overwhelming evidence has implicated it as the causal factor in the occurrence and relapse of peptic ulcer disease. The major objective of this study was to examine the extent to which physicians recognize H. pylori as a causal agent in peptic ulcer disease or as potential cofactor in other gastrointestinal diseases, and the extent to which this knowledge has influenced diagnostic and therapeutic practices.

Materials and Methods.

Using a national mail survey in Germany in September 1995, 1197 family practitioners and 1197 gastroenterologists were selected for the study.

Results.

Of the surveyed physicians, 756 (32%) responded. Family practitioners treated almost 50% of their patients with initial presentation of suspected ulcer disease without ordering further diagnostic tests. More than 25% of the family practitioners and 14% of the gastroenterologists reported that they do not treat diagnosed H. pylori infection in the first presentation of duodenal ulcer. At the time we conducted the study, 22% of responding family practitioners and 5% of responding gastroenterologists treated the first presentation of H. pylori‐positive ulcer disease with regimens determined to be ineffective according to the available literature.

Conclusions.

Gastroenterologists preferred to treat H. pylori infection when the associated disease was one for which a causal relationship had been more clearly established, while family practitioners showed less discrimination. In order to provide optimal therapy aimed at minimizing the course and consequences of H. pylori‐related diseases, researchers in the field must ensure continuous dissemination of current knowledge.
An Investigation of the Molecular Basis of the Spontaneous Occurrence of a Catalase‐Negative Phenotype in Helicobacter pylori
Authors: Manos Jim , Kolesnikow Tassia , Hazell Stuart L.
Published: March 2003

Background.

The discovery of a highly active catalase in Helicobacter pylori that in some strains may lose its activity has generated strong scientific interest. We have characterized a spontaneous catalase‐negative isolate of H. pylori (UNSW‐RU1) and sequenced katA in the parent strain and the promoters of both phenotypes as a prelude to understanding the genetic processes leading to the failure to express catalase.

Materials and Methods.

Protein extracts from both phenotypes were examined for catalase on 2D‐PAGE and analyzed by Western blot‐based immuno‐analysis. Presence of catalase mRNA was detected by Northern blot. Hi‐Fidelity PCR was used to sequence the katA promoter while katA was sequenced using cycle‐sequencing. The transcription start site was located by primer extension.

Results.

Catalase protein was absent in UNSW‐RU1 (KatA−) by 2D‐PAGE and Western blot, as was catalase mRNA by Northern blot, indicating that the cause of the KatA− phenotype was at the level of transcription. No mutations were found in the promoter region of the KatA− isolate. The transcription start site was identified 55 bp upstream of the ATG site and putative RNA polymerase binding sites were mapped at “−10” and “−35”. A Fur box was identified 181 bp upstream of the transcription start site. The sequences of an 876 bp ORF and a 366 bp Escherichia coli phnA homologue were identified.

Conclusions.

The UNSW‐RU1 (KatA−) phenotype does not express KatA or transcribe katA. The absence of defects in its promoter and a large part of its ORF indicates that loss of activity may be due to a mutation in an accessory gene essential for catalase expression, or to the binding of a repressor preventing katA transcription.
Highly Sensitive Urine‐Based Enzyme‐Linked Immunosorbent Assay for Detection of Antibody to Helicobacter pylori
Authors: Katsuragi Kiyonori , Noda Atsunari , Tachikawa Tetsuya , Azuma Atsushi , Mukai Fumie , Murakami Kazunari , Fujioka Toshio , Kato Mototsugu , Asaka Masahiro
Published: March 2003

Background.

Enzyme‐linked immunosorbent assay (ELISA) has been widely used for detection of Helicobacter pylori (H. pylori), but sample collection is often invasive, complicated, and expensive. Urine samples can be obtained noninvasively and are easier and safer to handle than serum samples. A urine‐based ELISA, if found to be accurate, would therefore be a useful alternative to serum‐based tests for H. pylori.

Methods.

An ELISA method was developed for detection of antibodies to H. pylori in urine. Its sensitivity and specificity were compared with those of three commercially available serum‐based ELISA kits and the 13C urea breath test (13C‐UBT) using samples from 99 healthy volunteers and 20 patients with gastric disorders.

Results.

With the assumption that 13C‐UBT results are 100% accurate, the sensitivity and specificity of the urinary ELISA were 99% and 100%, respectively, and the accuracy (99%) was superior to those of the three serum ELISAs tested. Immunostaining profiles on Western blot analysis using serum samples were almost identical to those obtained using paired urine samples.

Conclusions.

These findings suggest that the differences observed among ELISA test results may be due principally to differences between the profiles of antigen coated on plates for the assays, rather than to differences between antibodies in serum and urine. The urine‐based ELISA (URINELISA H. pylori) developed in this study is very accurate and would be useful for screening H. pylori infection as an alternative to serum ELISAs.
Practice Patterns for Peptic Ulcer Disease: Are Family Physicians Testing for H. pylori?
Authors: Zoorob Roger J. , Jones Glenn N. , Mainous Arch G. , Hagen Michael D.
Published: March 2003

Background. Peptic ulcer disease (PUD) is a problem common in family medicine. Recent evidence of Helicobacter pylori as an etiological agent of PUD has led to National Institutes of Health recommendations for treatment to eradicate H. pylori through antibiotic therapy. The purpose of this study is to examine practice patterns of family physicians in treating PUD, their use of H. pylori testing, and knowledge of current recommendations for PUD.

Materials and Methods. A mail survey was sent to a random sample of 1,500 members of the American Academy of Family Physicians. Six hundred thirty useable surveys (49.1%) were available for analysis. Descriptive statistics were obtained, as were inferential statistics focusing on the relationship of physician background characteristics to practices.

Results. Thirty‐eight percent of the respondents order diagnostic procedures for the majority (50% or more) of their suspected PUD cases. Of the physicians who reported ordering any diagnostic tests, 52% ordered the combination of upper gastrointestinal series and endoscopic gastroduodenoscopy. For patients with clinical diagnoses of PUD, 77% of doctors reported ordering a diagnostic test for H. pylori. Approximately 68% were aware that some kind of guidelines existed; only 11% reported that they were familiar with the National Institutes of Health recommendations for PUD.

Conclusions. Although some of the practices of family physicians for treatment of PUD deviate from current recommendations, the majority of practices are consistent with current evidence.
In Search of the Holy Grail of Heliocobacter pylori Remedies
Authors: Hopkins Robert J.
Published: March 2003

In this issue, Gisbert et al. (pp. 157–62) present the results of a noncomparative study evaluating a twice daily, 5‐day regimen of ranitidine bismuth citrate, amoxicillin, clarithromycin and metronidazole twice daily for Helicobacter pylori cure. This study is one of a few stuides that evaluate a 5‐day triple antimicrobial regimen in combination with a antisecretory agent. Although the study design precludes making any definite conclusion, it does encourage additional investigation of these types of regimens. Randomized controlled trials (RCTs) using regimens containing multiple agents should consider both standard‐of‐care comparator regimens and comparator regimens that will provide a better understanding of why regimens are more effective or better tolerated. The goal of treatment should be to maintain a lower bound 95% confidence interval (CI) of the point estimate of greater than 80% and a ‘delta’ (lower bound 95% CI of the difference in rates) of less than 10%. All RCTs should conduct susceptibility testing to evaluate the impact of resistance on efficacy and explain eradication failures. Finally, consideration should be given to the inclusion of patients with functional dyspepsia in H. pylori studies evaluating H. pylori cure since patients with peptic ulcer disease are becoming harder to find.
Variation in Serum Pepsinogens With Severity and Topography of Helicobacter pylori‐Associated Chronic Gastritis in Dyspeptic Patients Referred for Endoscopy
Authors: Bodger Keith , Wyatt Judy I. , Heatley Richard V.
Published: March 2003

Background.

It has long been recognised that specific patterns of gastritis are linked with different gastroduodenal diseases and that serum pepsinogens vary with the histological state of the gastric mucosa. With the discovery of the role of Helicobacter pylori in chronic gastritis and the availability of noninvasive tests for H. pylori infection, individuals with H. pylori gastritis can now be identified without endoscopic biopsy. However, without a knowledge of the pattern and severity of gastritis it is impossible to predict the likelihood of significant associated gastroduodenal pathology.

Aims.

The aim of this study was to evaluate the diagnostic potential of serum pepsinogens I and II in predicting the topography and severity of gastritis in H. pylori‐infected dyspeptic patients attending for endoscopy.

Methods.

Fasting serum was obtained from consecutive dyspeptic patients attending for endoscopy, and pairs of gastric biopsies obtained from the mid‐body and antrum. Gastritis was graded according to the Sydney System, and serum pepsinogen levels determined by radio‐immunoassay.

Results.

Sixty‐nine dyspeptic patients were studied (mean age: 49.6 years) of whom 34 had H. pylori‐associated chronic gastritis (Hp‐gastritis) – antral predominant gastritis (APG) in 41.2%, pangastritis (PAN) in 52.9%, and corpus predominant (CPG) in 5.9%. Serum pepsinogen II levels were significantly higher, and the serum pepsinogen I : II ratio significantly lower, in the H. pylori positive group than in other groups. Within the Hp‐gastritis group, there was a step‐wise decrease in serum pepsinogen I levels with progression from APG through PAN to CPG pattern (a cut‐off value of ≥ 100 ng/ml would have identified APG with a positive predictive value of 77%, though with low sensitivity). Within the Hp‐gastritis group, serum pepsinogen I and II levels were correlated with antral chronic inflammation score and serum pepsinogen II levels also with antral activity score. Serum pepsinogen I and the pepsinogen I : II ratio were lowest in severe gastric corpus atrophy.

Conclusion.

In dyspeptic patients known to be infected with H. pylori, serum pepsinogen values provide an assessment of the overall topography of gastritis, the severity of antral inflammation and the presence of severe corpus atrophy.
Treatment of Helicobacter pylori in Children With Recurrent Abdominal Pain
Authors: Wewer Vibeke , Andersen Leif P. , Pærregaard Anders , Gernow Anne , Hansen Jens P. H. , Matzen Peter , Krasilnikoff Peter A.
Published: March 2003

Background.

The role of Helicobacter pylori remains unclear in children with recurrent abdominal pain (RAP). In this study children with RAP were included in a double blind treatment study to elucidate whether symptoms disappear in children with a H. pylori infection and RAP, if the bacteria are eradicated.

Methods.

Thirty‐seven H. pylori‐infected children aged 4.9–14.5 years (median 9.8 years) with RAP were included. H. pylori was identified by histology and culture. The children were treated with amoxicillin and metronidazole for 14 days. A re‐endoscopy including biopsies for histology and culture was done at least one month after the end of treatment. Simple questions for symptoms were asked and blood for serology was repeated 3 and 6 months after the end of treatment. During the observation period the results of the re‐endoscopy and the serology 3 and 6 months after the re‐endoscopy were blinded for 23 patients and opened to 14 of the patients according to the choice of the families.

Results.

The eradication rates were 81% (30/37) in the total group and 74% (17/23) in the blinded group. The IgG antibodies to H. pylori decreased significantly 3 (p = .03) as well as 6 months after end of treatment (p < .001) in children with successful eradication. The number of children with RAP decreased after examination and treatment and the well‐being improved after 6 months in almost 95% of the children. However, no correlation was seen between eradication of H. pylori and disappearance of RAP, neither after 3 nor after 6 months’ observation in the total group of patients (p = .94 and p = .90) or in the blinded group (p = .42 and p = .65).

Conclusions.

These results do not provide evidence for a causal relationship between RAP and H. pylori.
T Cell‐Mediated Cytotoxicity via Fas/Fas Ligand Signaling in Helicobacter pylori‐Infected Gastric Corpus
Authors: Ishihara Shunji , Fukuda Ryo , Kawashima Kousaku , Moriyama Nobuyuki , Suetsugu Hiroshi , Ishimura Norihisa , Kazumori Hideaki , Kaji Takekazu , Sato Hiroshi , Okuyama Toshihiko , Rumi Karim M. A. , Adachi Kyoichi , Watanabe Makoto , Kinoshita Yoshikazu
Published: March 2003

abstract

Background.

Helicobacter pylori infection induces T helper‐1 immune responses in inflamed mucosa. However, the role of T cell‐mediated cytotoxicity in the induction of epithelial apoptosis is still unclear. The aim of this study was to investigate the involvement of the Fas/Fas ligand (Fas/Fas‐L) system in the H. pylori‐infected gastric corpus.

Materials and Methods.

Gastric fundic biopsy specimens were taken from patients with and without H. pylori infection. The expression of Fas and Fas‐L was examined by immunohistochemistry and RT‐PCR. Subsets of gastric infiltrating T cells in the biopsy specimens were studied by immunohistochemistry and flow cytometry. In histological sections, apoptosis was detected by the TUNEL method. We studied the in vitro expression of Fas‐L in peripheral T cells after stimulation with H. pylori antigen and interferon‐γ (IFN‐γ). The Fas‐mediated in vitro cytotoxicity of activated T cells was assessed by flow cytometry.

Results.

The numbers of CD4+ and CD8+ T cells were greater in H. pylori‐infected subjects. Fas expression was abundantly increased on fundic gland epithelium, and Fas‐L was detected on lamina propria mononuclear cells in H. pylori‐infected mucosa. TUNEL‐positive epithelial cells were also increased in H. pylori‐infected subjects. H. pylori antigen and IFN‐γ induced Fas‐L mRNA expression in both CD4+ and CD8+ T cells. In cytotoxic assay, activated T cells induced apoptosis in AGS cells, which could be significantly inhibited by neutralizing Fas‐L antibody.

Conclusions.

T cell‐mediated cytotoxicity via Fas/Fas‐L signaling may contribute to the induction of apoptosis in gastric epithelial cells during H. pylori infection.
Seroprevalence of Helicobacter pylori Infection in Siberia
Authors: Reshetnikov Oleg V. , Häivä Veli‐Mies , Granberg Christer , Kurilovich Svetlana A. , Babin Vladimir P.
Published: March 2003

Background.

Despite many population‐based epidemiological studies of Helicobacter pylori prevalence in different parts of the world, Russia still represents a ‘blank spot’ in this map. The aims of the present study were to evaluate the seroprevalence of H. pylori infection among the population of Siberia and to assess whether there is an association between abdominal symptoms and H. pylori positivity in our population.

Methods.

Six hundred and forty‐nine adults from five regions of Siberia and the Far East, and 79 children and adolescents from Novosibirsk participated in the study. Antibodies against H. pylori (IgG) were detected in serum using ELISA.

Results.

The total percentage of infected adults varied from 70% to 92% depending on the region, and was somewhat lower in three populations living to the north of the 60th latitude compared with those under the 60th latitude. A lack of association was found between the presence of H. pylori and the gender, age and abdominal symptoms. Almost maximum prevalence of H. pylori infection occurred by 30 years of age with only a minor increase in older age groups. Half the children were infected with H. pylori by the age of 15.

Conclusions.

Helicobacter pylori infection is widespread among the Siberian populations with some trend in its prevalence to decrease northward. In Siberia age‐specific prevalence rates of H. pylori infection are similar to those usual for developing countries.
Antibacterial Activities of β‐Lactamase Inhibitors Associated with Morphological Changes of Cell Wall in Helicobacter pylori
Authors: Horii Toshinobu , Mase Kiyomi , Suzuki Yasuhiro , Kimura Taku , Ohta Michio , Maekawa Masato , Kanno Takashi , Kobayashi Miya
Published: March 2003

Background. Recent study has demonstrated that β‐lactamase inhibitors including clavulanate, sulbactam and tazobactam have an vitro antibacterial effect on Helicobacter pylori. Here we describe the relationship between viability and cell profiles of H. pylori exposed to β‐lactamase inhibitors and some antibiotics in a short‐time course.

Materials and methods. The antibacterial effects of β‐lactamase inhibitors including clavulanate, sulbactam and tazobactam on the bacterial viability of and morphological changes in H. pylori ATCC43504 were examined.

Results. The β‐lactamase inhibitors such as clavulanate and sulbactam alone decreased the viable counts of H. pylori, depending on the antibiotic concentrations. Exposure to these β‐lactamase inhibitors resulted in morphological changes of cell shape, cell‐wall disintegration and cell lysis. Among these β‐lactamase inhibitors, clavulanate was the most active, causing a decrease in viable counts and morphological changes such as short filamentous to sphaeroplast formation and lysis. One × minimum inhibitory concentration (MIC) of amoxicillin plus 1 × MIC of clavulanate decreased viable counts effectively compared with 1 × MIC of amoxicillin or 1 × MIC of clavulanate alone, and induced morphological changes of cell shape and cell wall.

Conclusion. Our results suggest that the β‐lactamase inhibitors alone have concentration‐dependent antibacterial activities against H. pylori and affect the morphology of the cell shape and the cell wall in vitro.
Helicobacter pylori does not Mediate the Formation of Carcinogenic N‐Nitrosamines
Authors: Vermeer I. T. M. , Gerrits M. M. , Moonen E. J. C. , Engels L. G. J. B. , Dallinga J. W. , Kleinjans J. C. S. , Van Maanen J. M. S. , Kuipers E. J. , Kusters J. G.
Published: March 2003

Background. Both N‐nitroso compounds and colonization with Helicobacter pylori represent known risk‐factors for the development of gastric cancer. Endogenous formation of N‐nitroso compounds is thought to occur predominantly in acidic environments such as the stomach. At neutral pH, bacteria can catalyze the formation of N‐nitroso compounds. Based on experiments with a noncarcinogenic N‐nitroso compound as end product, and using only a single H. pylori strain, it was recently reported that H. pylori only displays a low nitrosation capacity. As H. pylori is a highly diverse bacterial species, it is reasonable to question the generality of this finding. In this study, several genetically distinct H. pylori strains are tested for their capacity to form carcinogenic N‐nitrosamines.

Materials and Methods. Bacteria were grown in the presence of 0–1000 µM morpholine and nitrite (in a 1 : 1 molar ratio), at pH 7, 5 and 3.

Results. Incubation of Neisseria cinerea (positive control) with 500 µM morpholine and 500 µM nitrite, resulted in a significant increase in formation of N‐nitrosomorpholine, but there was no significant induction of N‐nitrosomorpholine formation by any of the H. pylori strains, at any of the three pH conditions.

Conclusion. H. pylori does not induce formation of the carcinogenic N‐nitrosomorpholine in vitro. The previously reported weak nitrosation capacity of H. pylori is not sufficient to nitrosate the more difficultly nitrosatable morpholine. This probably also holds true for other secondary amines. These results imply that the increased incidence of gastric cancer formation that is associated with gastric colonization by H. pylori is unlikely to result from the direct induced formation of carcinogenic nitrosamines by H. pylori. However, this has to be further confirmed in in vivo studies.
Aberrant Expression of CDX2 in the Gastric Mucosa With and Without Intestinal Metaplasia: Effect of Eradication of Helicobacter pylori
Authors: Satoh Kiichi , Mutoh Hiroyuki , Eda Akashi , Yanaka Ichiro , Osawa Hiroyuki , Honda Sayaka , Kawata Hiroshi , Kihira Ken , Sugano Kentaro
Published: March 2003

Background. The intestine‐specific transcription factor CDX2 plays an important role in differentiation and maintenance of intestinal epithelial cells. Development and progression of intestinal metaplasia (IM) in the stomach is closely associated with Helicobacter pylori‐gastritis. We investigated expression of CDX2 protein in the gastric mucosa with and without IM before and after eradication of H. pylori.

Materials and Methods. The subjects comprised five normal controls and 29 H. pylori‐positive patients (15 with antral IM and 14 without IM), who were followed for 12 months after eradication of H. pylori. Biopsies were taken from the greater curvatures of the antrum and middle body. Expression of CDX2 was evaluated immunohistochemically using anti‐CDX2 antibody.

Results. CDX2 expression was not found in controls. Strong nuclear staining was observed extensively in IM, but rarely in the gastric epithelium, except for the focal area in only four antral biopsies (three with and one without IM). Fine granular cytoplasmic staining was also observed in the perinuclear regions of IM and the gastric epithelial cells in half of the patients. In 13 of the 15 patients with IM, IM did not regress after eradication of H. pylori, and the extent of nuclear staining in IM did not change. The extent of cytoplasmic staining did not change either.

Conclusions. Our results indicate that CDX2 expression in the gastric mucosa is found in patients with chronic gastritis and is closely associated with IM. CDX2 expression in IM or the gastric epithelial cells did not disappear after eradication of H. pylori.
Seroreactivity to 19.5‐kDa Antigen in Combination with Absence of Seroreactivity to 35‐kDa Antigen is Associated with an Increased Risk of Gastric Adenocarcinoma
Authors: Chua Tju Siang , Fock Kwong Ming , Chan Yiong Huak , Dhamodaran Subbiah , Sim Chee Seng , Ng Tay Meng , Teo Eng Kiong
Published: March 2003

Background. Only a minority of those infected with Helicobacter pylori will develop gastric cancer. Stratification of H. pylori strains based on carcinogenic potential will provide a basis for selective surveillance and eradication therapy. We studied the anti‐H. pylori antibody profile in Asian patients with gastric adenocarcinoma to identify any H. pylori antigen that may be associated with an increased or decreased risk of gastric carcinoma.

Patients and Methods. A case‐control study comparing the seroprevalence of antibodies with various H. pylori antigens in Singaporeans with gastric adenocarcinoma and the normal Singaporean population was carried out using both conventional immunoglobulin (Ig) G enzyme‐linked immunosorbent assay (ELISA) and Western blot immunoassay.

Results. The seroprevalence among 44 gastric adenocarcinoma cases (70.5% males, mean age 66.7 ± 13.5 years) and 261 controls (49.8% males, mean age 61.5 ± 4.1 years) was 90.9% vs. 50.2% by IgG ELISA. In the H. pylori‐positive male population, those suffering from gastric adenocarcinoma had significantly lower seroreactivity to the 35‐kDa antigen compared with asymptomatic controls (p = .0198, OR = 3.79, 95% CI 1.24–11.61). Seropositivity to the 19.5 kDa antigen was also found to be associated with the presence of gastric adenocarcinoma in Singaporean males (p = .022, OR = 4.17, 95% CI 1.22–14.28). A ‘high‐risk’ phenotype consisting of absence of a band at 35‐kDa in combination with the presence of a band at 19.5‐kDa was significantly associated with the presence of gastric adenocarcinoma (p = .002, OR = 3.7, 95% CI 1.6–8.6).

Conclusions. Stratification of H. pylori strains based on their potential for carcinogenesis, such as those strains that are seropositive for the 19.5 kDa antigen and seronegative for the 35‐kDa antigen, may provide a basis for selective eradication of H. pylori infection and future vaccine development.
Relationship Between Gastric Ulcer and Helicobacter pylori VacA Detected in Gastric Juice Using Bead‐ELISA Method
Authors: Shirasaka Daisuke , Aoyama Nobuo , Sakashita Masanori , Kuroda Kohei , Maekawa Shuji , Wambura Casmir Marwa , Miyamoto Masaki , Tamura Takao , Yahiro Kinnosuke , Wada Akihiro , Kurazono Hisao , Hirayama Toshiya , Kasuga Masato
Published: March 2003

Background. VacA is an important pathogenetic factor produced by Helicobacter pylori. VacA has often been detected in supernatants of liquid cultures or lysates of whole bacterial cells. However, no studies have ever tried to assay VacA produced in the human stomach. We applied a very sensitive and simple method, bead‐ELISA, to detect VacA in gastric juice.

Materials and Methods. Forty‐eight H. pylori‐positive patients (16 nonulcer dyspepsia, 16 gastric ulcer, and 16 duodenal ulcer) and four H. pylori‐negative nonulcer dyspepsia patients had endoscopy performed and gastric juice were aspirated. Polystyrene beads coated with the antibody to VacA, were used in this bead‐ELISA method. The nucleotide sequences of vacA in the signal and middle regions were investigated.

Results. Of the 48 samples that were positive for H. pylori, 21 [43.8%] were found to be VacA positive in gastric juice. The average and maximum concentrations of detected VacA in gastric juice were 143.2 ± 216.5 and 840 pg/ml, respectively. The average density of VacA from gastric ulcer patients (227.5 ± 276.7 pg/ml) was higher than that found in nonulcer dyspepsia (51.8 ± 39.8 pg/ml) and duodenal ulcer (49.2 ± 21.5 pg/ml) patients. There was no relationship between VacA in gastric juice and vacA genotype.

Conclusions. VacA in gastric juice could be directly detected by bead‐ELISA. In this study, the diversity of disease outcome was associated with not the quality but the quantity of VacA. Therefore, not only the quality but also the quantity of VacA is important etiological factors in the pathogenesis of mucosal damage.