bluuebunny/crossref_metadata_2025_split huggingface dataset:
Central osmotic regulation of sympathetic nerve activity
Authors: Toney G. M. , Chen Q. H. , Cato M. J. , Stocker S. D. 
Published: March 2003

AbstractAim: In this review, we will focus on the central neural mechanisms that couple osmotic perturbations to changes in sympathetic nerve discharge, and the possible impact these actions have in cardiovascular diseases such as arterial hypertension and congestive heart failure.Results: Changes in extracellular fluid osmolality lead to specific regulatory responses in defence of body fluid and cardiovascular homeostasis. Systemic hyperosmolality is well known to stimulate thirst and the release of antidiuretic hormone. These responses are largely due to osmosensing neurones in the forebrain lamina terminalis and hypothalamus and are critical elements in a control system that operates to restore body fluid osmolality. An equally important, but less characterized, target of central osmoregulatory processes is the sympathetic nervous system.Conclusion: Understanding the neurobiology of sympathetic responses to changes in osmolality has important implications for body fluid and cardiovascular physiology. By stabilizing osmolality, vascular volume is preserved and thereby relatively normal levels of cardiac output and arterial pressure are maintained.
Strength and power changes of the human plantar flexors and knee extensors in response to resistance training in old age
Authors: Ferri A. , Scaglioni G. , Pousson M. , Capodaglio P. , Van Hoecke J. , Narici M. V. 
Published: March 2003

Abstract Aim:  The aim of the present study was to assess and compare the improvements of muscle strength and power induced by a 16‐week resistive programme in a population of 16 older men aged 65–81 years.Methods:  Training was performed three times per week at an intensity of 80% of one repetition maximum (1RM) and consisted of both calf raise and leg press exercises. Before‐, during‐ and after‐training, maximum isometric and isokinetic torques, maximum power, 1RM, muscle cross‐sectional area (CSA) and electromyographic activity (EMG) of the plantar flexors (PF) and knee extensors (KE) were examined.Results:  For the KE and PF, respectively, training resulted in a 29.9 ± 4.4% (mean ± SE) and 21.6 ± 5.4% increase in 1RM (P < 0.001–0.01), a 19.4 ± 4.3 and 12.4 ± 4.7% (P < 0.001–0.05) increase in maximum isometric torque, and a 24.1 ± 6.3 and 33.1 ± 10.9% (P < 0.05) increase in maximum muscle power, calculated from torque–angular velocity curves. The large increase in torque and power was partly accounted by a significant increase in the CSA of the PF (5.0 ± 0.7%) and KE (7.4 ± 0.7%), while no significant changes in integrated EMG activity of vastus lateralis and soleus muscles, and in extrapolated maximum shortening velocity were found. After training, a significant increase in torque/CSA (10.3 ± 4%, P < 0.05) was found for the KE but not for the PF.Conclusion:  Hence, hypertrophy cannot alone justify the increase in torque, and other factors, such as an increase in individual fibre‐specific tension (in the case of KE), a decrease in antagonist muscles' coactivation, an improved co‐ordination and an increased neural drive of the other heads of quadriceps may have contributed to the increments in strength. The significant increase in muscle power seems particularly noteworthy with respect to daily activities involving the displacement of the body over time, namely, the generation of muscle power.
Amazing chloride channels: an overview
Authors: Nilius B. , Droogmans G. 
Published: March 2003

Abstract Aim:
This review describes molecular and functional properties of the following Cl
–
channels: the ClC family of voltage‐dependent Cl
–
channels, the cAMP‐activated transmembrane conductance regulator (CFTR), Ca
2+
activated Cl
–
channels (CaCC) and volume‐regulated anion channels (VRAC). If structural data are available, their relationship with the function of Cl
–
channels will be discussed. We also describe shortly some recently discovered channels, including high conductance Cl
–
channels and the family of bestrophins. We illustrate the growing physiological importance of these channels in the plasma membrane and in intracellular membranes, including their involvement in transepithelial transport, pH regulation of intracellular organelles, regulation of excitability and volume regulation. Finally, we discuss the role of Cl
– channels in various diseases and describe the pathological phenotypes observed in knockout mice models.
Sympathetic control of white adipose tissue in lean and obese humans
Authors: Dodt C. , Lönnroth P. , Wellhöner J. P. , Fehm H. L. , Elam M. 
Published: March 2003

AbstractAim:  To induce lipolysis, catecholamines could reach the adipocyte via the blood stream after being released from the adrenal medulla or, alternatively, via neuronal release in the vicinity of the fat cell. Sympatho‐neuronal effects on fat tissue lipolysis have been demonstrated in experimental animal models. However, the role of sympathetic nerves in the control of lipolysis in human white adipose tissue, which is sparsely innervated, has not been clarified.Conclusion:  The present review summarizes evidence for a direct neuronal influence on lipolysis in humans.
Chemoreflexes – physiology and clinical implications
Authors: Kara T. , Narkiewicz K. , Somers V. K. 
Published: March 2003

AbstractThe chemoreflexes are important modulators of sympathetic activation. The peripheral chemoreceptors located in the carotid bodies respond primarily to hypoxaemia. Central chemoreceptors located in the region of the brainstem respond to hypercapnia. Activation of either the hypoxic or hypercapnic chemoreflex elicits both hyperventilation and sympathetic activation. During apnoea, when the inhibitory influence of stretch of the pulmonary afferents is eliminated, there is a potentiation of the sympathetic response to both hypoxia and hypercapnia. This inhibitory influence of the pulmonary afferents is more marked on the sympathetic response to peripheral compared with central chemoreceptor activation. The arterial baroreflexes also have a powerful inhibitory influence on the chemoreflexes. This inhibition is again more marked with respect to the peripheral compared with central chemoreflexes.In patients with hypertension, there is a marked increase in the sympathetic and ventilatory response to hypoxaemia. During apnoea, with elimination of the inhibitory influence of breathing, the sympathetic response in untreated mild hypertensive patients is strikingly greater than that seen in matched normotensive controls. This potentiated peripheral chemoreflex sensitivity in hypertension may be explained in part by impaired baroreflex function in these patients. Enhanced peripheral chemoreflex sensitivity is also evident in patients with obstructive sleep apnoea. This peripheral chemoreflex enhancement is not explained by obesity, as obese individuals have a selective potentiation of the central chemoreceptors with peripheral chemoreflex responses similar to those seen in lean controls. Increased sensitivity to hypoxaemia has important implications in patients with obstructive sleep apnoea who experience repetitive and severe hypoxaemic stress. Tonic activation of the chemoreflex may also contribute to the high levels of sympathetic activity evident even during normoxic daytime wakefulness in sleep apnoea patients. Administration of 100% oxygen in patients with sleep apnoea results in reductions in heart rate, blood pressure and central sympathetic outflow.In patients with heart failure, the central chemoreflex response to hypercapnia is markedly and selectively enhanced. This increased central chemoreflex sensitivity may contribute to the development of central sleep apnoea in heart failure patients. Administration of 100% oxygen does not lower sympathetic activity in patients with heart failure, providing further evidence against any peripheral chemoreflex potentiation.The peripheral and central chemoreflexes have powerful effects on sympathetic activity in both health and disease and may contribute importantly to disease pathophysiology, particularly in conditions such as hypertension, obstructive sleep apnoea and heart failure.
Growth features of Acacia tortilis and Acacia xanthophloea seedlings and their response to cyclic soil drought stress
Authors: Otieno D. O. , Kinyamario J. I. , Omenda T. O. 
Published: March 2003

AbstractSeedlings of Acacia tortilis (Forsk) Hyne and Acacia xanthophloea Benth. were raised under controlled glasshouse conditions. Control plants were watered daily while other treatments involved withholding water for 2, 4 and 6 days with 1‐day rehydration to container capacity.Compared to A. tortilis, A. xanthophloea seedlings showed higher leaf area, relative growth rates and total dry weight production under adequate water supply conditions. However, with increased water stress, A. xanthophloea seedlings could not alter their pattern of carbon allocation, retaining their root : shoot (r : s) ratio of about 0.5. By comparison, A. tortilis seedlings shifted carbon allocation to the roots, leading to a r : s ratio of 1.5 in water‐stressed seedlings, compared to 0.5 in the control plants.The ability of A. tortilis to reallocate carbon to the roots away from the shoots and to actually increase root growth compared to A. xanthophloea was a dehydration postponement strategy that may be important in species survival during drought.
Vegetation dynamics of coastal sand dunes near Malindi, Kenya
Authors: Musila W. M. , Kinyamario J. I. , Jungerius P. D. 
Published: March 2003

AbstractThis study describes the composition, structure and distribution of coastal dune vegetation near Malindi, Kenya. The vegetation was made up of 156 plant species. Sixty families were recorded with Gramineae (seventeen species) and Papilionaceae (sixteen species) being the most widely represented. Fifteen plant communities were described in the different geomorphologic units. The plant communities exhibited a distinct zonal distribution. Halopyrum mucronatum and Ipomoea pes‐caprae plant communities were common in the unstable geomorphologic units. Cordia somaliensis and Pluchea dioscoridis plant communities were common in the more stable geomorphologic units. Most of the plants in the more stable geomorphologic units were shrubs and trees. Succulent herbs were identified in the slacks and the drowned valley, which have moist and damp environments.
Changes in miombo woodland cover in and around Sengwa Wildlife Research Area, Zimbabwe, in relation to elephants and fire
Authors: Mapaure Isaac N. , Campbell Bruce M. 
Published: March 2003

AbstractOne of the consequences of impacts of elephants and fire on woodlands is a change in woody cover, which often results in major challenges for wildlife managers. Changes in miombo woodland cover in and around Sengwa Wildlife Research Area (SWRA) between 1958 and 1996 were quantified by analyzing aerial photographs. Woody cover in SWRA decreazed from 95.2% in 1958 to 68.2% in 1996, with a lowest mean of 62.9% in 1983. The annual absolute rate of woody cover change in SWRA increazed from −1.1% per annum between 1958 and 1964 to a recovery of 1.6% per annum between 1993 and 1996, while the annual relative rate increazed from −1.1% per annum between 1958 and 1964 to 3.3% per annum between 1993 and 1996. There was a strong negative correlation between elephant densities and woody cover in SWRA, suggesting that loss of woody cover was mainly due to elephants. Woodland recovery after 1983 was due to reductions in elephant populations through legal and illegal off‐take and reductions in fire frequency. Surrounding areas experienced less woody cover losses than SWRA, mainly due to tree removal by locals whose densities increazed after the eradication of tsetse fly in the 1970s.
Diet of Mackinder's eagle owl Bubo capensis mackinderi in the alpine zone of Mount Kenya
Authors: Rödel Heiko G. , Scholze Wolfgang W. A. , Kock Dieter 
Published: March 2003

AbstractThe diet of Bubo capensis mackinderi Sharpe in the alpine zone of Mt. Kenya was studied by analysing pellets collected from nesting and roosting sites in four different valleys. Overall, mammals comprised 97.4% of prey individuals and 98.9% of the ingested biomass. Rodents, mainly groove‐toothed rats, were the owl's staple food in all four valleys, but rock hyrax, insectivores and birds were also consumed. Proportions of rock hyrax, rodents and insectivores did not differ between the valleys. Total dietary composition in the different valleys showed a high degree of overlap in proportions of main prey types averaging 93.2% in percentage of occurrence and 85.0% in percentage of biomass.
Increased expression of epidermal growth factor receptors in basal cell hyperplasia of the oesophagus after acid reflux oesophagitis in rats
Authors: Fujiwara Y. , Higuchi K. , Takashima T. , Hamaguchi M. , Watanabe T. , Tominaga K. , Oshitani N. , Matsumoto T. , Arakawa T. 
Published: March 2003

Background:Epidermal growth factor (EGF), which binds to EGF receptors (EGF‐R), stimulates oesophageal epithelial cell proliferation, enabling rapid repair after mucosal injury. In the normal human oesophageal epithelium, EGF‐R expression is present and confined to the basal layer.Aim:To examine histological changes in and dynamics of EGF‐R expression during healing after acid reflux oesophagitis in a rat model.Methods:Gastric acid reflux oesophagitis was induced in Wistar rats by ligation of the pylorus and the transitional region between the forestomach and the grandular portion for 5 h, followed by release of both ligations. Rats were killed 7 and 14 days after production of oesophagitis to examine macroscopic and histological changes as well as dynamics of EGF‐R expression. Epithelial cell proliferation was assessed by bromodeoxyuridine (BrdU) uptake, and expression of EGF‐R mRNA and protein by RT–PCR and Western blotting or immunohistochemistry.Results:Gastric acid reflux induced erosive and ulcerative mucosal lesions in the lower and middle part of the oesophagus. These lesions were healed by 14 days and histologically showed thickening of the oesophageal epithelium from 41.11 ± 3.09 μm in controls to 142.73 ± 11.59 μm (P < 0.001) in ligated rats, as well as elongation of papillae and basal cell hyperplasia. The number of BrdU‐positive cells among basal cells on day 14 was significantly increased from 7.1 ± 0.8/field in controls to 30.9 ± 3.0/field in ligated rats. Expression of EGF‐R mRNA and protein was significantly increased on day 14 and most basal cells were immunohistochemically positive in both BrdU and EGF‐R staining.Conclusion:Acid reflux‐induced oesophageal injury caused basal cell hyperplasia with an increase in cell proliferation and EGF‐R expression. Activation of EGF‐R gene and protein in response to acid reflux‐induced injury may facilitate mucosal healing. These results suggest that epidermal growth factor receptors play a crucial role in healing after acid reflux oesophagitis in rats.
Review article: gastric acidity − comparison of esomeprazole with other proton pump inhibitors
Authors: Hatlebakk J. G. 
Published: March 2003

SummaryGastric acid suppression is the most effective medical therapy to control acidic gastro‐oesophageal reflux: individuals in whom therapy fails usually have inadequate acid suppression. Twenty‐four‐hour intragastric pH‐metry measures the percentage of time that gastric pH is above 4 or 3, the critical thresholds for tissue damage and symptom generation in the distal oesophagus. Effective medical therapy must control gastric acidity throughout the daytime, including the postprandial period. It is therefore useful to report the percentage of patients in whom gastric acidity is controlled above pH 4 for at least 16 out of 24 h. Esomeprazole was compared with standard‐dose proton pump inhibitors in healthy volunteers and patients with gastro‐oesophageal reflux disease. Esomeprazole, 40 mg daily, was significantly more effective at controlling gastric acidity above pH 4 for more than 16 h than lansoprazole, 30 mg daily (38% of individuals vs. 5%, respectively). Esomeprazole, 40 mg daily, also suppressed gastric acidity more effectively and in more individuals than pantoprazole, 40 mg daily, and rabeprazole, 20 mg daily. Esomeprazole, 20 mg daily, was significantly more effective at controlling gastric acidity than lansoprazole, 15 mg daily. The improved acid control with esomeprazole compared with other proton pump inhibitors is likely to result in superior healing rates and improved symptom relief, with fewer therapy‐resistant patients.
Ranitidine bismuth citrate with either clarithromycin 1 g/day or 1.5 g/day is equally effective in the eradication of H. pylori and healing of duodenal ulcer
Authors: Dobrilla  , Matteo  , Dodero  , Fratton  , Iaquinto  , Loriga  , Marchi  , Marzio  , Muratori  , Pacini  , Saggioro  , Savarino  , Spinelli  , Zamboni  , Fina  , Tosatto  , Olivieri  
Published: March 2003

Background:No randomized double‐blind studies have been performed to compare clarithromycin 1 g/day with higher doses of the macrolide (1.5 g/day) when combined with ranitidine bismuth citrate (RBC).Aim:To compare H. pylori eradication and ulcer healing rates of RBC 400 mg b.d. for 4 weeks combined for the first 2 weeks either with clarithromycin 500 mg b.d. (Group A) or clarithromycin 500 mg t.d.s. (Group B).Methods:Two hundred and seventy‐three patients with H. pylori‐positive active duodenal ulcer were included. H. pylori infection was detected by CLO‐test and histology on antral and corpus biopsies before and at least 4 weeks after the end of therapy. Eradication was assumed if both CLO‐test and histology results were negative for H. pylori.Results:Eradication/healing rates according to intention‐to‐treat and per protocol analysis were 76/82% and 87/92% for Group A and 78/85% and 88/95% for Group B, respectively (P = N.S.). Adverse events were reported by 7% and 12% of patients in Groups A and B, respectively, and they were generally mild.Conclusions:RBC in co‐prescription with clarithromycin 500 mg b.d. is as effective as RBC plus clarithromycin 500 t.d.s. in eradicating H. pylori and healing duodenal ulcers.
Lansoprazole triple therapy for Helicobacter pylori—is 5 days enough?
Authors: O’connor  , McLoughlin  , Kelly  , Laundon  , Cunnane  
Published: March 2003

Background:Seven‐day proton pump inhibitor triple therapy is currently the treatment of choice for Helicobacter pylori infection. It is unclear whether triple therapy for less than 7 days might preserve efficacy while at the same time improving patient acceptability and compliance.Aim:To evaluate the Helicobactericidal efficacy, ulcer healing capacity and patient acceptability of a 5‐day lansoprazole‐based triple therapy regimen.Methods:Sixty‐nine consecutive patients with H. pylori‐positive peptic ulcer received lansoprazole 30 mg twice daily in combination with metronidazole 400 mg twice daily and clarithromycin 250 mg twice daily for 5 days. Ulcer healing medication was not continued after the 5‐day regimen. H. pylori status was assessed before and at least 4 weeks after therapy by rapid urease test and histology. Adverse events and compliance were assessed by direct questioning.Results:All 69 patients attended for repeat endoscopy and 63 were H. pylori‐negative after therapy giving a cure rate of 91% (95% Cl: 85–98%). Of the 59 patients with active ulcers, 58 were healed at repeat endoscopy giving an ulcer healing rate of 98% (95% Cl: 92–100%). All patients fully complied with therapy and mild adverse events, mainly gastrointestinal, were reported by 11 patients (16%).Conclusions:Five‐day lansoprazole triple therapy is an effective regimen for H. pylori infection which combines a high cure rate and ulcer healing efficacy with the advantages of excellent patient acceptability and compliance.
Hypergastrinaemia during long‐term omeprazole therapy: influences of vagal nerve function, gastric emptying and Helicobacter pylori infection
Authors: Schenk  , Kuipers  , Klinkenberg‐Knol  , Bloemena  , Nelis  , Festen  , Jansen  , Biemond  , Lamers  , Meuwissen  
Published: March 2003

Aim:To elucidate the mechanisms that lead to severe hypergastrinaemia during long‐term omeprazole therapy for gastro‐oesophageal reflux disease (GERD).Patients and methods:A total of 26 GERD patients were studied during omeprazole maintenance therapy. Twelve patients with severe hypergastrinaemia (gastrin > 400 ng/L) were compared with 14 control patients (gastrin < 300 ng/L). Helicobacter pylori serology and a laboratory screen were obtained in all patients. Gastric emptying was scored by the evidence of food remnants upon endoscopy 12 h after a standardized meal. Gastric antrum and corpus biopsies were analysed for histological parameters, as well as somatostatin and gastrin concentrations. All patients underwent a meal‐stimulated gastrin test and the hypergastrinaemia patients also underwent a vagal nerve integrity assessment by pancreatic polypeptide testing (PPT).Results:Severe hypergastrinaemia patients had a longer duration of treatment (80 vs. 55 months; P = 0.047) and were characterized by a higher prevalence of H. pylori infection (9/12 vs. 2/14, P = 0.004), corpus mucosal inflammation and atrophic gastritis (P < 0.04). This was reflected in lower serum pepsinogen A concentrations (mean ± S.E.M. 53.6 ± 17.9 vs. 137 ± 16.0 mg/L, P = 0.03), pepsinogen A/C ratio (1.8 ± 0.3 vs. 4.1 ± 0.6, P = 0.005) and mucosal somatostatin concentrations (2.75 ± 0.60 vs. 4.48 ± 1.08 mg/g protein, P = 0.038). Two patients in the hypergastrinaemia group had signs of delayed gastric emptying, but none in the normogastrinaemia group did (P = N.S.). In addition, both groups had a normal meal‐stimulated gastrin response.Conclusion:Severe hypergastrinaemia during omeprazole maintenance therapy for GERD is associated with the duration of therapy and H. pylori infection, but not with abnormalities of gastric emptying or vagal nerve integrity.
Pantoprazole 20 mg is effective for relief of symptoms and healing of lesions in mild reflux oesophagitis
Authors: Dettmer A. , Vogt R. , Sielaff F. , Lühmann R. , Schneider A. , Fischer R. 
Published: March 2003

Aim:To investigate the efficacy of a low dose of pantoprazole, a gastric proton pump inhibitor, for the relief of symptoms and healing of lesions in mild gastro‐oesophageal reflux disease (GERD), and to compare it with the efficacy of ranitidine.Methods:Patients with endoscopically established GERD (Stage I, Savary–Miller classification) were enrolled into a randomized, double‐blind, parallel‐group and multicentre study (intention‐to‐treat n = 209, age range 19–82 years). They were treated once daily with oral pantoprazole 20 mg or ranitidine 300 mg, for up to 8 weeks. End‐point parameters included relief of symptoms (heartburn, acid regurgitation, pain on swallowing) and the healing of GERD lesions. Relief from symptoms was assessed after 2 and 4 weeks, and endoscopically confirmed healing of lesions after 4 and 8 weeks.Results:The proportion of patients reporting complete relief from symptoms after 2 weeks was greater in the pantoprazole than in the ranitidine group (69 vs. 48%, P < 0.01), with further improvements seen in the pantoprazole group after 4 weeks (80 vs. 65%, P < 0.05, Cochran–Mantel/Haenszel test). Healing of lesions was confirmed in 70/87 (80%) patients after 4 weeks (pantoprazole group), as compared with 55/86 (64%) patients (ranitidine group) (P < 0.05, per protocol population); after 8 weeks the respective results were 78/87 (90%) and 63/86 (73%) patients (P < 0.01). Both study medications were well tolerated.Conclusion:Low‐dose pantoprazole (20 mg) is clinically superior to ranitidine (300 mg) in providing fast relief from symptoms and healing of lesions in patients with mild GERD.