bluuebunny/crossref_metadata_2025_split huggingface dataset:
Randomized, comparative, double‐blind study of amlodipine vs. nicardipine as a treatment of isolated systolic hypertension in the elderly
Authors: Mounier‐Véhier Claire , Jaboureck Olivier , Emeriau Jean‐Paul , Bernaud Corine , Clerson Pierre , Carre Alain 
Published: March 2003

AbstractA 90‐day, multicenter, randomized, double‐blind, parallel‐group study was conducted to compare the efficacy of amlodipine (once a day) with nicardipine (two to three times a day), in the treatment of isolated systolic hypertension (ISH) in the elderly. Patients (n = 133) aged ≥60 years, with ISH were randomized to receive either amlodipine 5 mg/day, or nicardipine 60 mg/day (titrated if necessary to 10 mg/day and 100 mg/day, respectively) for 90 days. Efficacy was assessed by measuring office blood pressure (BP), and 24‐h ambulatory blood pressure monitoring (ABPM). The two treatments substantially and comparably reduced office systolic blood pressure (SBP) and pulse pressure (PP), and also produced a slight decrease in diastolic blood pressure (DBP). Amlodipine reduced SBP, as assessed by ABPM, to a significantly greater extent than nicardipine. Both treatments were well‐tolerated. The sustained effect of amlodipine, compared with nicardipine, was reflected in its significantly greater antihypertensive activity, particularly during the nocturnal period, as assessed by ABPM. The study demonstrates that once a day dose of amlodipine is an effective antihypertensive treatment for elderly ISH patients.
Insulin resistance, a new target for nitric oxide‐delivery drugs
Authors: Cook Stéphane , Scherrer Urs 
Published: March 2003

AbstractIn the Western hemisphere, the incidence of insulin resistance and its complications has been growing rapidly and is reaching epidemic proportions. Over the past decade, evidence has accumulated, indicating that nitric oxide (NO) plays a key role in the regulation of metabolic and cardiovascular homeostasis. Defective endothelial nitric oxide synthase (eNOS) driven NO synthesis causes insulin resistance, arterial hypertension and dyslipidemia in mice, and characterizes insulin‐resistant humans. On the other hand, stimulation of inducible nitric oxide synthase (iNOS) and NO overproduction in mice, may also cause metabolic insulin resistance, suggesting a Yin–Yang effect of NO in the regulation of glucose homeostasis. Here, we will review the evidence for this novel concept, and thereby provide the conceptual framework for the use of NO‐delivery drugs and pharmacological agents that modulate the bioavailability of endogenously produced NO for the treatment of insulin resistance.
Impairment of vascular and platelet levels of nitric oxide and cyclic guanosine‐3′,5′‐monophosphate in cyclosporin A‐induced hypertensive rats
Authors: Santiago Margarida , Reis Flávio , Almeida Luís , Alcobia Teresa , Dionísio Joaquim , Teixeira Frederico 
Published: March 2003

ABSTRACT The therapeutic use of the immunosuppressive agent cyclosporin A (CsA) is associated with arterial hypertension and increased risk of thromboembolism. Impaired endothelium‐mediated relaxation is one of the main hypotheses explaining the CsA‐induced vascular hyper‐reactivity. Since nitric oxide (NO) modulates both vascular and platelet activity, we studied the effects of CsA on the levels of arterial and platelet NO as well as 3′,5′‐cyclic guanosine monophosphate (cGMP) levels which are influenced by NO. An animal model of CsA‐induced hypertension was used. Wistar rats were treated with a clinically relevant, oral dose of 5 mg/kg CsA, daily, for 4 weeks. CsA increased both systolic and diastolic blood pressures compared to non‐treated rats (P < 0.01). Nitrite, a NO metabolite, decreased in the entire aorta wall (30%, P < 0.05) and in the aorta wall without the endothelial layer (70 %, P < 0.05) in CsA‐treated vs. control groups. cGMP content was also decreased in the CsA‐treated group (67%, P < 0.01) vs. control. Taken together, these results suggest a defect on the endothelial NO generation, acceleration of breakdown and/or consumption of NO, as well as marked alterations directly on cGMP metabolism. Conversely, platelet nitrite and cGMP content significantly increased in the CsA‐treated rats, which was also observed in in vitro studies of platelet nitrite release following CsA treatment. This suggests a platelet self‐regulation mechanism against CsA‐induced platelet hyper‐reactivity, which, in turn, could compensate vascular impairment.
Effects of aspirin on N‐α‐tosyl l‐arginine methyl ester [TAME]‐esterase induced contractions on rat aorta in vitro
Authors: Gurib Fatmah Bibi Housnah , Subratty Anwar Hussein 
Published: March 2003

AbstractThe present study was designed to investigate whether N‐α‐tosyl l‐arginine methyl ester [TAME]‐esterase activation could be the result of endothelial dysfunction. Thoracic aorta from rats was mounted in an organ bath containing Krebs solution. Intact and endothelium denuded aortic strips were challenged with different concentrations of TAME (10−15–10−1 m). The effects of aspirin, a cyclo‐oxygenase pathway inhibitor, were also studied on [TAME]‐esterase induced contraction on rat aorta strips. Our results showed that aspirin definitely blocked TAME‐esterase induced contractions on rat aortic strips.In conclusion, the present work supported the hypothesis that [TAME]‐esterase induced contraction in rat aorta in vitro was mediated through release of prostaglandin(s) as a result of endothelial dysfunction.
Effects of endurance training on heart rate and blood pressure variability
Authors: Uusitalo Arja L. T. , Laitinen Tomi , Väisänen Sari B. , Länsimies Esko , Rauramaa Rainer 
Published: March 2003

Purpose: To study the influences of a 1‐year controlled, randomized endurance exercise training period on heart rate (HR) and blood pressure variability in a representative sample of Finnish men in their late middle age. Methods and results: Subjects were 140 sedentary men aged 53–63 years. The men were randomized into two identical groups: an intervention (EX) and a reference (CO) group. One hundred and twelve of them remained in the final analysis (EX: n=59, CO: n=53). EX trained for 30–60 min three to five times a week with the intensity of 40–60% of maximal oxygen consumption. In EX, 1 year of regular exercise training increased oxygen consumption at respiratory compensation threshold by 11% (P ≤ 0·001) in a maximal cardiorespiratory test. Total power and very low frequency power of R–R interval variability (ms2) tended to increase in the EX group by 26 and 42% and to decrease in the CO group by 13 and 10% (interaction P<0·05 and P<0·01), respectively. There were no significant changes in blood pressure variability. Conclusion: Regular low‐ to moderate‐intensity exercise training could retard the decli‐ning tendency in cardiac autonomic nervous function in older men during 1 year.
Validation of a newly developed B‐mode image‐processing technique versus wall‐tracking ultrasound for the study of wall mechanics in small‐calibre arteries
Authors: Vernhet Hélène , Demaria Roland , Juan Jean M. , Oliva‐Lauraire Marie C. , Quéré Isabelle , Gariépy Jérôme , Sénac Jean P. , Dauzat Michel 
Published: March 2003

Purpose: To validate a newly developed image‐processing technique for the assessment of arterial wall compliance and distensibility from non‐invasive B‐mode ultrasound compared with the invasive wall‐tracking technique. Materials and methods: Arterial wall compliance and distensibility coefficient were measured invasively by wall‐tracking with an ultrasonic transducer implanted on the vessel wall, and non‐invasively by automatic processing of B‐mode ultrasound images, with a dedicated workstation and software (IO^ 3·1, IO^DP, Paris). Measurements were performed in the normal aorta of five animals, and upstream, at the stent level, and downstream from the stent in eight other animals (immediately after stenting in six, and 3 months later in four), for a total of 35 paired measurements. Results: There was no significant difference between the two techniques for compliance but there was a significant difference in diameter (P<0·005) and distensibility (P<0·05) as external ultrasound measured the inner diameter, while wall‐tracking measured the outer diameter. Agreement between the two methods as assessed by the Bland–Altman approach was acceptable for aortic diameter, compliance and distensibility. Conclusion: Automatic processing of B‐mode ultrasound images is a reliable non‐invasive technique to assess the compliance of small‐calibre arteries.
Female gender increases stiffness of elastic but not of muscular arteries in type I diabetic patients
Authors: Ahlgren Å. Rydén , Sundkvist G. , Sandgren T. , Länne T. 
Published: March 2003

SummaryThe reason for the particularly increased risk for cardiovascular complications in diabetic women is still unclear. We have previously found decreased distensibility of elastic arteries in type I diabetic women, indicating increased cardiac load, not seen in type I diabetic men, which might be one contributing factor. Whether the effect of gender is different in muscular arteries in type I diabetic patients has not been assessed. As estimates of arterial distensibility we measured stiffness (β) and pressure strain elastic modulus (Ep) in the muscular common femoral artery using echo‐tracking sonography in 30 women (mean age 34 years, range 20–61) and 26 men (mean age 38 years, range 22–56) with type I diabetes. The results were compared with those of 89 healthy individuals of corresponding age and gender and with previously published results from elastic arteries in these patients obtained at the same occasion. The internal common femoral diameter was significantly decreased in both diabetic men and women. In sharp contrast to the highly significant decreased distensibility of the elastic abdominal aorta and common carotid artery in the type I diabetic women, the distensibility of the common femoral artery did not clearly differ between patients and controls, neither for women nor for men. Thus, the gender difference in changes of arterial distensibility found in elastic arteries was absent or far less obvious in the femoral artery. In conclusion, female gender seems to affect the mechanical properties of elastic, but not of large muscular arteries in type I diabetic patients. Thus, putative gender differences in arterial changes in type I diabetes are to be sought in elastic rather than muscular arteries.
Determining Minimum Habitat Areas and Habitat Corridors for Cougars
Authors: Beier Paul 
Published: March 2003

I simulated population dynamics of cougars to predict the minimum areas and levels of immigration needed to avoid population extinction caused by demographic and environmental stochasticity for a period of 100 years. Under most plausible parameter values, the model predicted very low extinction risk in areas as small as 2200 km2, and (in the absence of immigration) increasing risk as area decreased below 2200 km2. If as few as one to four animals per decade could immigrate into a small population, the probability of population persistence increased markedly. Thus a corridor for immigration will benefit a small population in an area where further loss of habitat will occur.The model was applied to the cougar population in the Santa Ana Mountain Range of southern California (2070 km2, with about 20 adults). Field data support the model’s conclusion that this population is demographically unstable. There will be a high risk of extinction if the habitat is reduced to currently protected and connected areas (1114 km2). A movement corridor allowing immigration from the adjacent population and intra‐range corridors would greatly enhance the prognosis. However, the last corridor for immigration has been degraded by recent human activity. Within the mountain range, cougars recently became extinct in a 75 km2 habitat fragment recently isolated by development, and cougars will become extinct in another 150 km2 of habitat if a proposed housing project occludes a critical corridor. Radio tracking has confirmed use of this and other important corridors.Neither the model nor the field data alone would have much influence in the face of development pressure; together they have stimulated interest in restoring and protecting critical corridors in this range. Nonetheless, the long‐term prognosis for this populations is bleak, because 22 local governments review potential impact on a case‐by‐case basis. Effective land‐use planning must be spatially explicit and regional in scope. Because cougars need corridors and because telemetered cougars can quickly identify movement corridors, cougar research is an efficient and appropriate way to inject biological data into such planning efforts.
Baby Friendly Hospital Practices: Cesarean Section is a Persistent Barrier to Early Initiation of Breastfeeding
Authors: Rowe‐Murray Heather J. , Fisher Jane R.W. 
Published: March 2003

Background: Documented barriers to the implementation of Step 4 of the Baby Friendly Hospital Initiative, which relates to early initiation of breastfeeding, have not considered the impact of operative intervention in delivery on achievement of the goal. This study was designed to test the hypothesis that hospital practices in the immediate postpartum period that are associated with operative intervention in delivery can affect first mother‐infant contact and initiation of breastfeeding.Methods:  In a prospective, longitudinal study, a sociodemographically representative sample of 203 primiparous women was recruited. Participants were interviewed at 2 days postpartum in metropolitan hospitals in Melbourne, Australia, and medical records were inspected. At 8 months postpartum 81 percent of participants completed a postal questionnaire. Three mode‐of‐delivery groups (spontaneous vaginal delivery, instrumentally assisted vaginal delivery and cesarean section) and 4 hospital‐of‐delivery groups (including one accredited Baby Friendly Hospital) were compared.Results:  Two way ANOVA revealed that women who had a cesarean section experienced a significant delay in initiating breastfeeding compared with women giving birth vaginally, with or without instrumental assistance (p<0.001). Significant differences in this aspect of care were also observed among hospitals, with the Baby‐Friendly hospital performing significantly better than the other three hospitals (p <0.001). An effect due to mode of delivery alone was demonstrated that could not be abolished by differences in hospital practices (p=0.231). Nevertheless, shorter elapsed time between birth and initiation of breastfeeding was not significantly associated with continuation of breastfeeding at 8 months postpartum (p=0.642).Conclusions:  The findings confirmed that cesarean section was a significant barrier to the implementation of Baby Friendly Hospital Initiative Step 4 and that hospital practices were amenable to changes that enabled its implementation regardless of the mode of delivery. (BIRTH 29:2 June 2002)
H. pylori and cagA: Relationships with Gastric Cancer, Duodenal Ulcer, and Reflux Esophagitis and Its Complications
Authors: Graham David Y. , Yamaoka Yoshio 
Published: March 2003

Background. Helicobacter pylori infection is accepted to be associated with two mutually exclusive diseases: duodenal ulcer and gastric cancer. Attention has recently focused on possible relationships between H. pylori and gastroesophageal reflux disease and its complications such as adenocarcinoma of the gastric cardia. The aim of this study was to provide a framework for explaining the seemingly paradoxical associations between H. pylori and various gastrointestinal diseases.Methods.Available data regarding H. pylori infection, cagA, acid secretion, corpus gastritis, and gastroesophageal reflux disease (GERD) and its complications are reviewed, and testable hypotheses are presented.Results.Linking the type of H. pylori (cagA‐positive vs. cagA‐negative), the pattern and intensity of inflammation, and acid secretion explains the apparent paradoxes in the associations between H. pylori and gastric cancer, duodenal ulcer, and GERD. Although H. pylori is inhibited by bile, a duodenal acid load sufficient to lower the average pH to precipitate bile acids overcomes that inhibition. H. pylori that contain a functional cag pathogenicity island produce a vigorous inflammatory response. The severity of mucosal inflammation predicts likelihood of different outcomes (e.g., in the bulb with likelihood of developing duodenal ulcer, and in the corpus with the degree of reduction in acid secretion and the rate of development of multifocal atrophic gastritis). Development of H. pylori corpus gastritis is promoted by profound inhibition of acid secretion (e.g., childhood infections or a high level of antisecretory therapy). The CagA protein, or the cagA gene, is a marker for enhanced inflammation, but CagA is not directly involved in the pathogenesis of gastric cancer or duodenal ulcer disease, nor is it a reliable indicator of the presence of a functional cag pathogenicity island.Conclusion.The relationship between the type of H. pylori infection, presence or absence of a functional cag pathogenicity island, corpus inflammation, and acid secretion explains the duodenal ulcer/gastric cancer paradox and the relationship between H. pylori infection and the complications of GERD. The predicted rank order for the presence of GERD and its complications (peptic stricture, Barrett’s esophagus, and adenocarcinoma of the gastric cardia) is highest in the population without H. pylori infection, less in those with H. pylori infection, and least in those infected with cagA‐positive H. pylori. Controversy and confusing epidemiological observations will continue unless future studies provide data on the gastric corpus histology (or acid secretion) as well as regarding the presence or absence of a functional and intact cag pathogenicity island of the infecting organism.
In Vitro Aging of Helicobacter pylori: Changes in Morphology, Intracellular Composition and Surface Properties
Authors: Enroth Helena , Wreiber Karin , Rigo Robert , Risberg Dag , Uribe Andres , Engstrand Lars 
Published: March 2003

Background.During the conversion from the bacillary into the coccoid form, Helicobacter pylori organisms are known to change extensively. The aim of this study was to determine some of the changes that occur regarding morphology, intracellular composition and surface properties during the aging of bacteria in vitro.Materials and Methods. H. pylori from agar plate cultures of different ages was used in this study. The intracellular composition of the two morphological forms of the bacteria was tested by density centrifugation, DNA extraction and quantitative OD, mRNA and ATP measurements. Immunoblotting was used to observe changes in secreted/superficial protein patterns, and hydrophobicity measurements were used to observe changes in surface properties.Results.All bacillary H. pylori organisms changed morphology gradually over 10 days of culture. Rods had a higher density than cocci; bacteria stored in PBS had the highest density and bacteria stored in water had the lowest. The quantitative DNA, RNA and ATP content were reduced in the aging bacteria. Fewer immunogenic proteins were expressed, and an increased surface hydrophobicity was observed in the older cultures.Conclusion.This study highlights several aspects of H. pylori aging in vitro and shows some of the differences that exist between bacillary and coccoid forms. This information is important for understanding the transmission and survival of H. pylori outside the human host, as the degradative changes in the intracellular composition and the surface properties shown here point to dead bacteria, and not to a viable but nonculturable form.
Predominance of a Single Strain of Helicobacter pylori in Gastric Antrum
Authors: Hua Jiesong , Ng Han Chong , Yeoh Khay Guan , Ho Bow 
Published: March 2003

Background.Diversity of DNA among H. pylori strains isolated from different patients can serve as a useful marker for differentiating strains. DNA profiles of H. pylori obtained from sequential gastric biopsies were identical in most patients indicating that a given strain can persist from months to years. Patients colonized with more than two strains isolated mainly from different anatomical sites have been reported. This work examined whether the gastric antrum of patients with dyspepsia is colonized by single or multiple strains of H. pylori as well as the in vitro competition of different strains of H. pylori.Materials and Methods.Two antral biopsy specimens from each of the 124 patients were cultured for H. pylori. DNA fingerprinting of H. pylori isolates was performed using random amplified polymorphic DNA (RAPD) analysis. To elucidate the possible interaction among H. pylori isolates, bacterial populations of two H. pylori strains cogrown in broth medium over 21 days were enumerated and DNA fingerprinting was compared.Results.A total of 58 patients showed the presence of H. pylori in both antral specimens, while five patients had H. pylori in only one of the two samples. These 58 patients were shown to harbor a single strain of H. pylori as analyzed by RAPD fingerprinting. In vitro studies of bacterial interaction of two different strains of H. pylori showed growth competition resulting in the predominance of a single strain.Conclusions.The results support the concept that a single strain predominates in the gastric antrum site of patients studied.