bluuebunny/crossref_metadata_2025_split huggingface dataset:
Landscape heterogeneity, connectivity, and critical landscapes for conservation
Authors: Malanson George P. , Cramer Barton E. 
Published: March 2003

SummaryLandscapes are diverse in the frequencies and distributions of habitat types. Does landscape heterogeneity, as a higher order (i.e. at a pheno‐ menological scale coarser than that of organisms) of diversity, allow greater connectivity; does higher order diversity change higher order functions? Climatic change and habitat fragmentation require that plant and animal species move across varied landscapes. Mediterranean‐type ecosystems provide contrasts in landscape heterogeneity. In order to assess potential impacts of either and thus to propose remedial measures, it is necessary to understand general classes of connectivity in landscapes. We developed six rules for movement (random, persistent, and directionally biased for both movement throughout habitat and restricted to habitat edges), which we simulated on three general landscape patterns (random, hierarch‐ ical, and fractal) with different degrees of habitat fragmentation. Organisms that move only on the edge of habitat patches are more successful with a moderate amount of fragmentation but are less successful overall and especially in the non‐random landscapes. Particular structures can thus differentiate connectivity for different vectors. We propose that general rules derived from simulations can be applied to the identification of landscapes that are near critical levels of fragmentation and which will respond sensitively to small increases in fragmentation or small efforts at restoration. Mediterranean‐type ecosystems are well suited to test this proposal because of contrasting patterns and changes in fragmentation.
Native and naturalized plant diversity are positively correlated in scrub communities of California and Chile
Authors: Sax Dov F. 
Published: March 2003

Abstract. An emerging body of literature suggests that the richness of native and naturalized plant species are often positively correlated. It is unclear, however, whether this relationship is robust across spatial scales, and how a disturbance regime may affect it. Here, I examine the relationships of both richness and abundance between native and naturalized species of plants in two mediterranean scrub communities: coastal sage scrub (CSS) in California and xeric‐sloped matorral (XSM) in Chile. In each vegetation type I surveyed multiple sites, where I identified vascular plant species and estimated their relative cover. Herbaceous species richness was higher in XSM, while cover of woody species was higher in CSS, where woody species have a strong impact upon herbaceous species. As there were few naturalized species with a woody growth form, the analyses performed here relate primarily to herbaceous species. Relationships between the herbaceous cover of native and naturalized species were not significant in CSS, but were nearly significant in XSM. The herbaceous species richness of native and naturalized plants were not significantly correlated on sites that had burned less than one year prior to sampling in CSS, and too few sites were available to examine this relationship in XSM. In post 1‐year burn sites, however, herbaceous richness of native and naturalized species were positively correlated in both CSS and XSM. This relationship occurred at all spatial scales, from 400 m2 to 1 m2 plots. The consistency of this relationship in this study, together with its reported occurrence in the literature, suggests that this relationship may be general. Finally, the residuals from the correlations between native and naturalized species richness and cover, when plotted against site age (i.e. time since the last fire), show that richness and cover of naturalized species are strongly favoured on recently burned sites in XSM; this suggests that herbaceous species native to Chile are relatively poorly adapted to fire.
Effects of tramadol on behavioural indicators of colic pain in a rat model of ureteral calculosis
Authors: Affaitati Giannapia , Giamberardino Maria Adele , Lerza Rosanna , Lapenna Domenico , De Laurentis Silvana , Vecchiet Leonardo 
Published: March 2003

This study investigated the effect of prolonged administration of tramadol vs. placebo on behavioural indicators of ureteral pain and referred lumbar muscle hyperalgesia in a rat model of artificial ureteral calculosis.Four groups of 10 rats each (female, Sprague‐Dawley) were treated twice a day, for 4 days, with i.p. injections of tramadol 1.25 mg/kg, 2.5 mg/kg, 5 mg/kg or saline, respectively. The first injection was delivered 45 min before laparotomy (under pentobarbital anaesthesia) for formation of the stone in the upper left ureter via injection of dental cement. All rats were video‐taped 24 h non‐stop from the immediate postoperative period until the 4th day for recording of behavioural ureteral crises indicative of colic pain. Lumbar muscle sensitivity was tested daily over the same period by verifying presence or absence of vocalization upon pinching of the parietal layers at L1 level, bilaterally, at a constant predefined pressure value with calibrated forceps.Tramadol significantly reduced number and global duration (ANOVA, P < 0.008 and P < 0.004) of ureteral crises with respect to saline and the effect was dose‐dependent (linear regression analysis between doses and parameters of crises, P < 0.003 and P < 0.002). The drug also significantly reduced the incidence of referred muscle hyperalgesia (ANOVA, P < 0.0001). It is concluded that tramadol is highly effective in controlling pain phenomena from urinary stones and can represent a valid therapeutic approach in patients with urinary colics.
New insights in insurmountable antagonism
Authors: Vauquelin G. , Van Liefde I. , Birzbier B. B. , Vanderheyden P. M. L. 
Published: March 2003

AbstractAntagonists that produce parallel rightward shifts of agonist dose–response curves with no alteration of the maximal response are traditionally classified as surmountable, while insurmountable antagonists also depress the maximal response. Although the longevity of the antagonist–receptor complex is quoted in many studies to explain insurmountable antagonism, slowly interconverting receptor conformations, allosteric binding sites, and receptor internalization have been evoked as alternative explanations. To complicate matters even further, insurmountable antagonism is not only drug‐related; it may also depend on the tissue, species and experimental design. For the sake of drug development, it is important to elucidate the molecular mechanisms of insurmountable antagonism. New experimental approaches, such as intact cell studies and the use of computer‐assisted simulations based on dynamic receptor models, herald the advent of better insight in the future.
In vitro effects of tacrolimus on human cytochrome P450
Authors: Lecointre K. , Furlan V. , Taburet A.‐M. 
Published: March 2003

AbstractTacrolimus, a potent immunosuppressive drug, is known to be metabolized predominantly in the liver by cytochrome P450 3A (CYP3A). In order to determine the potential of tacrolimus to inhibit the metabolism of other drugs, we have investigated its inhibitory effects on specific cytochrome reactions. Specific substrates for the seven cytochromes (CYPs) 1A2, 2A6, 2C9, 2C19, 2D6, 2E1 and 3A4/5 were incubated with human hepatic microsome preparations with or without specific inhibitors or tacrolimus and the metabolites were detected by high‐pressure liquid chromatography (HPLC) or fluorimetric methods. All the specific inhibitors reduced or abolished the specific CYP activity. Tacrolimus had no effect on any CYP at concentrations below 1 µm, while at higher concentrations it had a mild inhibitory effect on CYP3A4 and 3A5. These observations suggest that tacrolimus is unlikely to potentiate the effect of coadministered drugs through inhibition of their metabolism in the liver.
Non‐linear behaviour of respiratory movement in obstructive sleep apnoea syndrome
Authors: Miyata Masanori , Burioka Naoto , Suyama Hisashi , Sako Takanori , Nomura Takashi , Takeshima Takao , Higami Shigeru , Shimizu Eiji 
Published: March 2003

SummaryIn this study we investigated the non‐linear properties of respiratory movement in patients with obstructive sleep apnoea syndrome (OSAS) during sleep without and with nasal continuous positive airway pressure (nCPAP). To calculate the correlation dimension (D2) in respiratory movement we applied an algorithm proposed by Grassberger and Procaccia. Non‐linearity in respiratory movement was tested by comparing D2 for the original data with that for surrogate data. Respiratory movement was recorded from 10 patients with OSAS. D2 during both wakefulness with eyes closed and during sleep with nCPAP at 8 cm H2O could be computed in all subjects (2·50 ± 0·69 and 1·68 ± 0·17, respectively). On the other hand, D2 during sleep with apnoea could not be computed in patients with severe OSAS. These results indicate the abnormal properties of respiratory movement during apnoeic sleep in severe OSAS. Moreover, respiratory movement with nCPAP was shown to be non‐linear deterministic behaviour in respiratory movement during sleep. Analysis of D2 for respiratory movement may be useful in adjusting (titrating) nCPAP and classifying severity in OSAS.
Impact of Market Hunting on Mammal Species in Equatorial Guinea
Authors: FA JULIA E. , JUSTE JAVIER , DEL VAL JAIME PEREZ , CASTROVIEJO JAVIER 
Published: March 2003

Abstract: The impact of commercial hunting on forest mammals was studied in two regions on Bioko and Rio Muni in Equatorial Guinea, west Africa. Harvests were assessed from carcass counts in the main markets in the areas. A total of 10,812 carcasses of 13 species were recorded in Bioko, and 6160 carcasses of 30 species were recorded in Rio Muni. Biomass of harvested mammals was 111,879.63 kg in Bioko and 66,447.87 kg in Rio Muni. For the 12 prey species selected for study in Bioko, harvests totaled 7.15 animals/km2 or 62.93 kg/km2. Harvests for the 17 prey species in Rio Muni were 3.22 animals/km2 or 24.06 kg/km2. We used a model developed by Robinson and Redford (1991) to estimate potential harvests based on animal production rates. Total production was 147.90 animals/km2 and 139.12 animals/km2 in Bioko and Rio Muni, respectively. Potential harvest figures varied considerably by species. Comparison of actual and potential harvests showed that five primate species (Cercopithecus erythrotis, Cercopithecus nictitans, Cercopithecus pogonias, Cercopithecus preussi, and Mandrillus leucophaeus) and one ungulate (Cephalophus ogilbyi) in Bioko were being hunted unsustainably. Only two of the 17 species (Cercopithecus nictitans and Cephalophus dorsalis) in Rio Muni were being hunted unsustainably. Percent deviation of actual from potential harvests averaged 4.98 times greater than sustainable harvest in Bioko and 1.03 times greater in Rio Muni. For the two sites together figures ranged from close to 28 times greater than potential to 0.08% of the potential harvest. Although hunting methods and the commercialization potential of species may affect their presence in markets, these figures show that Bioko animals are heavily exploited, some of them unsustainably. This poses severe risks for the conservation of the island's unique fauna that must be addressed immediately.Impacto de la caza comercial sobre las especies de mamíferos en Guinea Ecuatorial
Breastfeeding Duration, Costs, and Benefits of a Support Program for Low‐Income Breastfeeding Women
Authors: Pugh Linda C. , Milligan Renee A. , Frick Kevin D. , Spatz Diane , Bronner Yvonne 
Published: March 2003

Background: Breastfeeding can ameliorate some of the complex health issues faced by low‐income families. Women who breastfeed and their infants have lower health care costs compared with those who formula feed. Increasing the duration of breastfeeding is recognized as a national priority, particularly for low‐income women. This community‐based randomized clinical trial involving low‐income mothers compared usual care with an intervention comprising hospital and home visits, and telephone support by a community health nurse/peer counselor team for 6 months after delivery.Methods: Forty‐one women were recruited after delivery of a full‐term singleton infant and randomly assigned to intervention or usual care groups.Results: Women receiving the community health intervention breastfed longer than the women receiving usual care. The infants in the intervention group had fewer sick visits and reported use of fewer medications than infants in the usual care group. The intervention cost ($301/mother) was partially offset by cost savings on formula and health care.Conclusions: Community health nurse and peer counselor support can increase breastfeeding duration in low‐income women, and has the potential to reduce total costs including the cost of support. (BIRTH 29:2 June 2002)
Satisfaction and Use of Prenatal Care: Their Relationship Among African‐American Women in a Large Managed Care Organization
Authors: Handler Arden , Rosenberg Deborah , Raube Kristiana , Lyons Sandra 
Published: March 2003

ABSTRACT:Background: Although many more mothers of almost all ethnic groups began prenatal care in the first trimester during the last decade, a significant number of low‐income and minority women still fail to obtain adequate care in the United States—a failure that may be related to their dissatisfaction with the prenatal care experience. This study sought to examine the relationship between satisfaction with care and subsequent prenatal care utilization among African‐American women using prospective methods.Methods: A sample of 125 Medicaid and 275 non‐Medicaid African‐American adult women seeking care through a large Midwest managed care organization were interviewed before or at 28 weeks’ gestation at one of two prenatal care sites. Women were interviewed about personal characteristics, prenatal care experience, and ratings of care (satisfaction). Information about subsequent use of prenatal care was obtained through retrospective medical record review after delivery. Univariate and multivariable analyses examining the relationship between women's satisfaction and prenatal care use were conducted using a dichotomous measure of satisfaction and a continuous measure of utilization.Results: Women were highly satisfied with prenatal care, with an overall mean satisfaction score of 80.3. Non‐Medicaid women were significantly (p < 0.05) less satisfied with their prenatal care (mean score, 79.1) than Medicaid women (mean score, 82.8), and the latter had significantly fewer visits on average than the former subsequent to the interview. Analyses showed no significant difference in subsequent utilization according to whether a woman had a high versus low level of satisfaction at the prenatal care interview.Conclusions: This study challenges the assumption that improving a woman's satisfaction with care will lead to an increase in the adequacy of her prenatal care utilization. Since this study was limited to African‐American women and is the first prospective study of women's satisfaction with care and prenatal care utilization, the negative findings do not yet settle this area of inquiry. Monitoring women's satisfaction with prenatal care in both managed care and fee‐for‐service settings and working to improve those aspects of care associated with decreased satisfaction is warranted. (BIRTH 30:1 March 2003)
Growth Inhibitory and Bactericidal Activities of Lansoprazole Compared with Those of Omeprazole and Pantoprazole against Helicobacter pylori
Authors: Nakao Masafumi , Malfertheiner Peter 
Published: March 2003

Background. Helicobacter pylori plays a role in the pathogenesis of both duodenal and gastric ulcers. The aim of this study was to evaluate the effect of the proton pump inhibitor (PPI), lansoprazole, commonly used in eradication regimens, on growth, bactericidal activity and morphology of H. pylori in vitro in comparison with other PPIs.Materials and Methods.Growth inhibitory activity of each of the PPIs was evaluated by determining minimum inhibitory concentrations using an agar dilution method. Bactericidal activity was determined by analysis of the viable cells in culture at various time points after incubation with different concentrations of the PPIs. Bacterial morphology was examined using scanning electron microscopy of fixed cells after exposure to the test substances. Urease activity in cell extracts of H. pylori that had been incubated with increasing concentrations of the PPIs was determined by colorimetry.Results.The growth inhibitory activity of lansoprazole was significantly more potent than that of omeprazole or pantoprazole (MIC90 6.25 vs. 25 and 100~μg/ml, respectively). Exposure of H. pylori to lansoprazole produced loss of viability and an aberrant bacterial morphology, which was more extensive than seen with omeprazole or pantoprazole. Lansoprazole dose dependently inhibited urease activity; its effectiveness was comparable with omeprazole but more potent than pantoprazole.Conclusions.The mechanism of action that leads to loss of viability of H. pylori cells appears to differ between the three PPIs investigated; lansoprazole was the most potent of the three agents in terms of growth inhibition and disruption of bacterial morphology.
Effect of Helicobacter pylori Eradication on Peptic Ulcer Disease Complicated with Outlet Obstruction
Authors: Taskin Vildan , Gurer Inanç , Ozyilkan Esin , Sare Mustafa , Hilmioglu Fatih 
Published: March 2003

Background. At present, the prevalence of Helicobacter pylori (H. pylori) in complicated peptic ulcer and the effect of H. pylori eradication on complicated peptic ulcer have not been fully established. In this study, we report the prevalence of H. pylori in peptic ulcer patients complicated with gastric outlet obstruction, effectiveness of oral eradication therapy on these patients, and their long‐term follow up.Patients and Methods. Ten consecutive patients presenting with clinically and endoscopically significant obstructed peptic ulcers were included in this study. During each endoscopy, seven gastric biopsy specimens were obtained and analyzed for H. pylori colonization.Results. The antral mucosal biopsy specimens were positive for H. pylori in nine patients. H. pylori infection was eradicated and complete ulcer healing was observed in all patients. The mean follow‐up period was 14 (7–24) months. One patient had duodenal perforation and underwent surgical intervention following medical treatment, despite the eradication of H. pylori. Ulcer recurrence was noted in two (22.2%) of nine patients, and in one of them the recurrent ulcer was complicated with obstruction (11.1%). The mean time to ulcer recurrence was 17 months (range, 10–24 months). The biopsies and CLOtests were H. pylori negative at the time of ulcer or erosion recurrence in two patients.Conclusion. We suggest that H. pylori eradication may improve the resolution in obstructive ulcer cases with colonization.
Inducible Nitric Oxide Synthase Expression in Gastroduodenal Diseases Infected with Helicobacter pylori
Authors: Son Hee Jung , Rhee Jong Chul , Park Dong Il , Kim Young‐Ho , Rhee Poong‐Lyul , Koh Kwang Cheol , Paik Seung Woon , Choi Kyoo Wan , Kim Jae J. 
Published: March 2003

AbstractBackground.Nitric oxide (NO) is synthesized enzymatically from L‐arginine by NO synthase, which is measured by inducible NO synthase (iNOS). Helicobacter pylori (H. pylori) infection produces a state of chronic immunostimulation in the gastric epithelium. Infection with cagA+H. pylori has greater degree of gastric inflammation and epithelial cell damage. Therefore, we compared the levels of iNOS in patients with H. pylori infection in relation to cagA status and H. pylori‐related disease.Materials and Methods.One hundred and seven patients, including 51 patients with gastric cancer, 12 patients with gastric ulcer, 18 patients with duodenal ulcer and 26 patients with chronic gastritis, were enrolled in this study. Biopsies from the antrum and body were obtained for histologic examination, culture and reverse transcriptionase‐PCR (RT‐PCR) for detection of iNOS gene expression. The presence of H. pylori was confirmed by Giemsa staining or culture and the gene expression of cagA in H. pylori isolates was confirmed by PCR.Results. H. pylori infection was detected in 70.1% (75/107) and cagA was detected in 84.8% (28/33). iNOS expression was detected in 49.5% (53/107) and there was no significant difference in iNOS expression according to H. pylori infection nor the cagA status in the gastroduodenal diseases. However, iNOS expression was more frequently detected in gastric cancer than the other H. pylori‐related diseases (64.7% vs. 35.7%, p < .05).Conclusion.Although NO was thought be involved in the gastric carcinogenesis, the level of NO production was not related to H. pylori infection or cagA status.
Helicobacter pylori in Gastric Cancer and Peptic Ulcer Disease in a Colombian Population. Strain Heterogeneity and Antibody Profiles
Authors: Piñeros Diana M. Cittelly , Riveros Sandra C. Henao , Marin Julian D. Martinez , Ricardo Oliveros , Díaz Oscar Orozco 
Published: March 2003

ABSTRACTBackground. Helicobacter pylori infection is associated with peptic ulcer disease and gastric cancer. The aim of this work was to describe, to compare H. pylori antigenic profiles, and to characterize the antibody response against Colombian strains in gastric cancer and peptic ulcer patients.Materials and Methods.Liquid culture supernatants were used to determine the antigenic profiles of 35 H. pylori strains by immunoblotting using a pool of positive sera. Characterization of strains included the evaluation of cytotoxic and vacuolating activities. The serologic antibody profiles of 124 patients (54 duodenal ulcer and 70 gastric cancer) were analyzed against two native strains (Hpu24, Hpc29) and NCTC11638. Antibodies to specific antigenic bands in each strain were related with presentation.Results.Differences among antigenic profiles were observed between native isolates with each serum recognizing a wide range of antigens (30–120 Kd). A 68 Kd band in Hpu24 strain was recognized by 50% of sera from peptic ulcer patients but not by gastric cancer sera (p = .000). The immune profiles differed according to the strain used (i.e. a given sera did not recognize the same bands in different strains). Detection of H. pylori in gastric mucosa was associated with the presence of antibodies against low molecular weight antigenic bands.Conclusions.The heterogeneity in the antibody response to H. pylori and the prevalence specific anti‐H. pylori antibodies in a specific disease depend on the strain used as antigen. The results support the hypothesis that there may be a differential antibody response to carcinogenic and ulcerogenic strains and suggest that there are antigenic bands that could be useful as markers of disease.