bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzyme activities in the tibialis anterior muscle of young moderately active men and women: relationship with body composition, muscle cross‐sectional area and fibre type composition
Authors: Jaworowski Å. , Porter M. M. , Holmbäck A. M. , Downham D. , Lexell J. 
Published: March 2003

AbstractThe aims of this study were (i) to assess the differences between men and women in maximal activities of selected enzymes of aerobic and anaerobic pathways involved in skeletal muscle energy production, and (ii) to assess the relationships between maximal enzyme activities, body composition, muscle cross‐sectional area (CSA) and fibre type composition. Muscle biopsies were obtained from the tibialis anterior (TA) muscle of 15 men and 15 women (age 20–31 years) with comparable physical activity levels. The muscle CSA was determined by magnetic resonance imaging (MRI). Maximal activities of lactate dehydrogenase (LDH), phosphofructokinase (PFK),β‐hydroxyacyl‐coenzyme A dehydrogenase (HAD), succinate dehydrogenase (SDH) and citrate synthase (CS), were assayed spectrophotometrically. The proportion, mean area and relative area (proportion × area) of type 1 and type 2 fibres were determined from muscle biopsies prepared for enzyme histochemistry [myofibrillar adenosine triphosphatase (mATPase)]. The men were significantly taller (+6.6%;P < 0.001) and heavier (+19.1%;P < 0.001), had significantly larger muscle CSA (+19.0%;P < 0.001) and significantly larger areas and relative areas of both type 1 and type 2 fibres (+20.5–31.4%;P = 0.007 toP < 0.001). The men had significantly higher maximal enzyme activities than women for LDH (+27.6%;P = 0.007) and PFK (+25.5%;P = 0.003). There were no significant differences between the men and the women in the activities of HAD (+3.6%; ns), CS (+21.1%;P = 0.084) and SDH (+7.6%; ns). There were significant relationships between height and LDH (r = 0.41;P = 0.023), height and PFK (r = 0.41;P = 0.025), weight and LDH (r = 0.45;P = 0.013), and weight and PFK (r = 0.39;P = 0.032). The relationships were significant between the muscle CSA and the activities of LDH (r = 0.61;P < 0.001) and PFK (r = 0.56;P = 0.001), and between the relative area of type 2 fibres and the activities of LDH (r = 0.49;P = 0.006) and PFK (r = 0.42;P = 0.023). There were no significant relationships between HAD, CS and SDH, and height, weight, muscle CSA and fibre type composition, respectively. These data indicate that the higher maximal activities of LDH and PFK in men are related to the height, weight, muscle CSA and the relative area of type 2 fibres, which are all significantly larger in men than women.
Paraventricular nucleus of the hypothalamus and elevated sympathetic activity in heart failure: the altered inhibitory mechanisms
Authors: Li Y.‐F. , Patel K. P. 
Published: March 2003

Abstract Aim:  There is a characteristic neurohumoral activation in heart failure (HF). However, few studies have been performed to examine the role of the central nervous system in the activation of sympathetic outflow during HF. In this paper we review some of our studies, with particular emphasis on examining the role of the paraventricular nucleus (PVN) in the exaggerated sympathetic outflow commonly observed in HF.Results:  Our studies have revealed that the inhibitory mechanisms regulating sympathetic outflow are mediated by nitric oxide (NO) and γ‐aminobutyric acid (GABA) within the PVN and are attenuated in HF. These alterations are associated with elevated sympathetic activity. Furthermore, these studies have indicated that the interactions among excitatory (angiotensin II and glutamate) and inhibitory (NO and GABA) neurotransmitters/mediators within the PVN significantly influence sympathetic outflow.Conclusion:  Reduced inhibitory actions of NO and/or GABA within the PVN may exaggerate an increase in the actions of excitatory neurotransmitters such as glutamate and angiotensin II within the PVN and this may contribute to the overall sympatho‐excitation commonly observed in HF.
Transmitter characteristics of cutaneous, renal and skeletal muscle small arteries in the rat
Authors: Tarasova O. , Sjöblom‐Widfeldt N. , Nilsson H. 
Published: March 2003

AbstractAim:  We studied transmitter characteristics of proximal and distal arteries supplying skin (saphenous artery and its medial tarsal branch), kidneys (terminal branches of renal artery and interlobar arteries) and skeletal muscle (proximal and distal sections of external sural artery).Methods:  Artery segments were mounted in an isometric myograph and intramural nerves were activated by electrical field stimulation. Adrenergic and purinergic components of the neurogenic response were blocked using phenoxybenzamine and α,β‐methylene adenosine triphosphate (mATP), respectively.Results:  Arteries from skin or kidney developed rapid and prominent neurogenic contractile responses, with half‐maximal amplitude reached within 5–15 s; responses in proximal vessels were greater than in distal vessels. Arteries from skeletal muscle responded to sympathetic stimulation with a moderate contraction developing over 1 min or more, the response of distal segments was greater than that of proximal segments. In skeletal muscle vessels the sympathetically evoked contraction was completely blocked by phenoxybenzamine, whereas in skin and renal vessels it was the combined effect of noradrenaline and adenosine triphosphate (ATP). Given alone, mATP did not change the magnitude of the response to nerve stimulation, but increased its latency and also potentiated the response to exogenous noradrenaline. In all vascular beds, distal vessels were more sensitive to noradrenaline and mATP.Conclusion:  It thus appears that the noradrenaline/ATP ratio of the sympathetic vasoconstrictor response differs between vascular beds in a way that is consistent with known differences in the selective regulation of regional vascular resistance by the sympathetic nervous system.
Renal and hormonal responses to isotonic saline infusion after 3 days' head‐down tilt vs. supine and seated positions
Authors: Mauran P. , Sediame S. , Pavy‐Le Traon A. , Maillet A. , Carayon A. , Barthelemy C. , Weerts G. , Guell A. , Adnot S. 
Published: March 2003

AbstractAim:  The study aimed to determine whether prolonged exposure to simulated microgravity produces a level of thoracic volume receptor loading similar to that seen in the upright position or immediately after lying down.Methods:  We used a cross‐over design to compare responses to a saline infusion in eight healthy subjects during a 4‐day, −6° head‐down tilt (HDT) and in the acute seated and acute supine positions.Results:  The first 24 h of HDT were associated with greater urinary excretion of water and sodium (UV, UNaV) than seated and acute supine [cumulative UV, 3035 ± 219, 2311 ± 156 (P < 0.05), and 2448 ± 182 mL (P < 0.05), respectively; cumulative UNaV, 256 ± 19, 180 ± 11 (P < 0.05), and 189 ± 15 mmol (P < 0.05), respectively]. Haemoglobin and haematocrit were increased after 24 h and plasma volume decreased after 48 h of HDT (P < 0.05). With prolongation of HDT, UV and UNaV returned near the baseline values, and plasma atrial natriuretic factor (ANF) and renin values returned to acute seated levels; in acute supine, ANF values were higher and renin lower than in the two other positions. After a 30‐min infusion of 20 mL kg−1 isotonic saline on the fourth HDT day or during acute seated or acute supine, sodium excretion within 4 h was similar during HDT and acute seated (83 ± 6 and 84 ± 9 mmol, respectively) and greater during supine (104 ± 8 mmol, P < 0.05). The renin decrease was greater in HDT and seated than in supine. The plasma ANF increase was greater during HDT than during supine; during seated, plasma ANF was unchanged.Conclusion:  These data suggest that, after 4 days of HDT, thoracic volume receptor loading returns to the same level as in the seated position, leading to blunted responses to volume expansion as compared with the acute supine position.
A leptin‐sympathetic‐leptin feedback loop: potential implications for regulation of arterial pressure and body fat
Authors: Mark A. L. , Rahmouni K. , Correia M. , Haynes W. G. 
Published: March 2003

AbstractAim:  This manuscript briefly reviews evidence and potential implications of a leptin‐sympathetic‐leptin feedback loop.Results:  Leptin increases sympathetic nerve activity to brown adipose tissue, kidney and other tissues. This action has implications for regulation of arterial pressure. In turn, there is evidence that sympathoadrenal stimulation inhibits leptin mRNA expression and secretion from white adipose tissue through beta adrenergic mechanisms.Conclusion:  This sympathetic modulation of leptin expression has potential implications for regulation of body fat.
Biomass density of wild and domestic herbivores and carrying capacity on a working ranch in Laikipia District, Kenya
Authors: Mizutani Fumi 
Published: March 2003

SummaryThis study of biomass densities of wild animals and domestic stock was carried out on the Lolldaiga Hills ranch in the Laikipia District, Kenya, between 1989 and 1995, as part of the study of the ecology of leopards and their impact on the working ranch. The ranch is set amongst the Lolldaiga Mountains, north‐west of Mount Kenya, and lies in ecological Zone IV. The vegetation in the area was classified as a scattered tree grassland. The weighted mean annual rainfall was 554 mm. The ranch carried 1543 kg km−2 of wild animals and 6512 kg km−2 of cattle and sheep. The ranch has produced beef, milk and wool since its foundation over 70 years ago, with a steadily maintained output and without any apparent degradation of the land. The milk production of normally over 450,000 kg per year was reduced, or ceased, in periods of drought and may represent a useful ‘safety valve’. The feasibility of multiple land use and conservation of wildlife are discussed.
Ecological condition of encroached and non‐encroached rangelands in Borana, Ethiopia
Authors: Angassa Ayana , Baars Robert M. T. 
Published: March 2003

AbstractThe range condition was assessed in six communal grazing areas and one Government ranch in both areas encroached by bushes or shrubs and non‐encroached areas. In each area, three altitude zones were distinguished and in each altitude zone one transect, covering both encroached and non‐encroached rangeland, away from water sources, was selected. The assessment was based on botanical composition of the herbaceous layer, basal cover, litter cover, relative number of seedlings, age distribution of grasses and soil condition. A total of 41 grasses, four legumes, three sedges and 28 tree and/or shrub species were identified. The grasses Aristida adscensionis, Cenchrus ciliaris, Chrysopogon aucheri and Panicum coloratum were common or dominant in all sampled areas. Pennisetum mezianum and Pennisetum stramineum were typically found in the encroached vegetation. In general, the range condition was good. The encroached vegetation had a significantly lower score for range condition than the non‐encroached vegetation for most of the parameters as well as for the total score, although the differences were small. Differences based on altitude and distance of sample sites from water sources within transects were not significant, except for the relative number of seedlings. No signs of overgrazing were detected.
Widespread ‘hilltopping’ in Acraea butterflies and the origin of sex‐role‐reversed swarming in Acraea encedon and A. encedana
Authors: Jiggins Francis M. 
Published: March 2003

AbstractIn some populations of the butterflies Acraea encedon and A. encedana, most females are infected with a bacterium that kills their sons. The resulting shortage of males is associated with females adopting a sex‐role‐reversed mating system, in which females swarm at landmarks such as hilltops and compete for males. We have observed the mating behaviour of Acraea species that are not known to be infected with the male‐killer. In over half of these species, males were found to aggregate on hilltops. It is likely that this behaviour was ancestral to the sex‐role‐reversed swarms of Acraea encedon and A. encedana, and we discuss how the spread of the male‐killing infection may have converted this mating system into sex‐role‐reversed swarming.
Modelling the energy budget of a colonial bird of prey, the Ruppell's griffon vulture, and consequences for its breeding ecology
Authors: Ruxton G. D. , Houston D. C. 
Published: March 2003

AbstractColonial nesting is rare in birds of prey. In this study we develop further Pennycuick's (1979) model of energy balance to consider the implications of colonial nesting for the breeding ecology of Ruppell's griffon vultures. To achieve a realistic foraging range, and remain in energy balance, the birds need to do more than fill their crop once on each foraging trip. They must remain in the feeding area and digest some of this food and refill the crop to obtain sufficient energy to pay for the flight costs and have sufficient energy to satisfy their own requirements and that of the chick. Given the known distances that the birds have to travel to forage, it would be impossible for them to rear more than one chick. The low growth rate of griffon vulture chicks may be an adaptation to the low rate at which energy can be delivered by the parents. The optimal time for a bird to be away from the nest changes with the distance they have to travel. Assuming that one parent remains on the nest at all times to guard the chick, it is optimal for both parents to take turns to forage on the same day if the distance to a feeding area is under 150 km, but to switch to each parent being away for a whole day when the distance is greater than this. Soaring flight is essential for such a scavenger, because of the low energy expenditure. If a vulture relied on the more energetically demanding flapping flight its maximum foraging range would be under 40 km. Griffon vultures are known to be able to depress their basal metabolic rate, and this has major implications for their foraging range, which then becomes constrained by the flight speed rather than by the amount of food they need to obtain. Griffon vultures minimize energy expenditure on all activities, because even small increases in their energy demands have a large impact on the foraging range that the bird can use.
Successful eradication of Helicobacter pylori prevents relapse of peptic ulcer disease
Authors: Tomita T. , Fukuda Y. , Tamura K. , Tanaka J. , Hida N. , Kosaka T. , Hori K. , Sakagami T. , Satomi M. , Shimoyama T. 
Published: March 2003

Background:The NIH consensus conference in 1994 recommended that all patients with peptic ulcers should be tested and treated for Helicobacter pylori. Recent studies have shown that the eradication of H. pylori is associated with a significant reduction in the relapse rate of peptic ulcers, but there are few reports about long‐term outcome.Aims:To evaluate the relapse rate of peptic ulcer in the long‐term follow‐up of patients after H. pylori eradication therapy.Patients and methods:Patients infected with H. pylori (445; 88 duodenal ulcer, 357 gastric ulcer) were randomly divided into three groups. In group A, patients received `conventional treatment' including acid decreasing therapy with a histamine H2‐receptor antagonist or proton pump inhibitor (PPI). In group B, patients received `dual therapy' including one antibiotic plus acid‐decreasing therapy. In group C, patients received `triple therapy' with PPI plus amoxicillin and clarithromycin. Eradication of H. pylori infection was assessed by histology of biopsy specimens from both the antrum and body corpus at 4 weeks, and 6 and 12 months after stopping therapy. Endoscopy was performed at intervals of 6 months for 5 years.Results:Intention‐to‐treat eradication rates for the duodenal ulcer patients were 0% for group A, 46% for group B and 80% for group C; eradication rates for the gastric ulcer patients were 0%, 33% and 83% respectively. No recurrence was noted in the duodenal ulcer patients and only 4% of gastric ulcers recurred after successful eradication during follow‐up for 5 years. In contrast, in patients with persistent H. pylori infection all DU and 92% of gastric ulcers recurred.Conclusion:Eradication of H. pylori infection changes the natural course of peptic ulcer.
A critical approach to new forms of treatment of Crohn's disease and ulcerative colitis
Authors: Seegers D. , Bouma G. , Peña A. S. 
Published: March 2003

SummaryMost patients with inflammatory bowel disease can be managed with conventional immunosuppressive therapy. The choice of agents to prevent relapses of inflammatory bowel disease must be based on efficacy, toxicity and cost. Studies in animal models of inflammatory bowel disease indicate that chronic intestinal inflammation results from enhanced immune responses to bacteria that are present normally in the lumen. Loss of tolerance, an abnormal function or defective healing of the mucosal barrier may all give raise to chronic intestinal inflammation. This hypothesis is the basis of new therapies aimed at either decreasing the levels of luminal bacterial antigens and/or selectively blocking detrimental mucosal immune responses. Anti‐TNF is an example of this novel approach that is very effective in Crohn's disease. The use of biological therapy is costly, however, and the long‐term complications are not yet known. The recent increase of tuberculosis in patients treated with anti‐TNF indicates that careful monitoring is necessary. It is clear that the new forms of treatment may play an important role in tailoring the appropriate drug to a specific group of patients. However, for the time being, fine‐tuning in the use of conventional immunosuppression is necessary. New knowledge in the pharmacogenetics of these compounds allows improvements to be made in their use. It is to be hoped that a critical approach in the use of current and future drugs, taking into account the advances in the aetiopathogenesis of inflammatory bowel disease, will contribute to the quality of life of patients with inflammatory bowel disease.
Overview: initial and long‐term management of gastro‐oesophageal reflux disease
Authors: Dent J. , Talley N. J. 
Published: March 2003

SummaryInitial management of gastro‐oesophageal reflux disease aims to confirm a symptom‐based diagnosis, to relieve symptoms, to reassure the patient as to the treatable nature of reflux disease, and to initiate risk management and healing of oesophagitis. The aims of long‐term management include adequate control of symptoms, prevention of complications, and improvement of quality of life. Management options in terms of use of proton pump inhibitors are either daily therapy (maintenance), intermittent courses of therapy (for example, 4 weeks, then cease and observe), or on‐demand therapy. This overview discusses the advantages and disadvantages of these different strategies for the management of reflux disease.
Review article: pharmacology of esomeprazole and comparisons with omeprazole
Authors: Dent J. 
Published: March 2003

SummaryPlasma concentration measurements have confirmed that the advantageous hepatic metabolism of esomeprazole results in a greater delivery of acid suppressant to the systemic circulation, compared with an equal dose of omeprazole. Also, this superior delivery has been shown to cause a more consistent and greater suppression of pentagastrin‐stimulated gastric acid secretion by esomeprazole, 20 mg, compared with omeprazole, 20 mg. The superior acid‐suppressant properties of esomeprazole have been revealed by extensive 24‐h intragastric pH‐monitoring studies. Compared with omeprazole, 20 mg, esomeprazole, 20 mg and 40 mg, has been shown to give superior outcomes on three key measures of antisecretory effect: (1) consistency amongst individuals; (2) duration over the 24‐h cycle; (3) overall impact on pH. As there is a substantial increment of acid control from esomeprazole, 20 mg, to esomeprazole, 40 mg, this latter dose is the most appropriate to investigate for modern initial therapy of reflux disease, with the aim of achieving the highest possible response rates in the shortest possible time.
Beclomethasone dipropionate enemas versus prednisolone sodium phosphate enemas in the treatment of distal ulcerative colitis
Authors: Campieri  , Cottone  , Miglio  , Manenti  , Astegiano  , D’arienzo  , Manguso  , D’albasio  , Bonanomi  , Galeazzi  , Orlando  , Castiglione  , Gionchetti  
Published: March 2003

Aim:To compare beclomethasone dipropionate 3 mg/60 mL enema (BDP) and prednisolone sodium phosphate 30 mg/60mL enema (PP) once daily in patients with active distal ulcerative colitis.Methods:One hundred and fifty‐seven patients were enrolled in a multicentre, 4‐week, randomized, double‐blind trial. Patients were assessed at baseline, 2 and 4 weeks.Results:Both treatment groups showed statistically significant improvement of clinical activity after 2 and 4 weeks. Endoscopy and biopsy showed a reduction in the activity score at the end of the treatment period in both groups. No statistically significant difference was observed between the two treatment groups. After 4 weeks, 29% of patients in the BDP group and 25% in the PP group were considered to be in clinical remission; an improvement was observed in 40% of patients on BDP and in 47% on PP. Mean morning plasma cortisol levels showed a slight but significant reduction in the PP group, while the ACTH test showed that neither drug interfered with the hypothalamic–pituitary–adrenal (HPA) axis function. No significant changes were observed in the laboratory tests. Finally, there was a low incidence of adverse events in both groups.Conclusions:It is concluded that, in the topical treatment of active distal ulcerative colitis, BDP 3 mg enemas are as efficacious as PP 30 mg enemas, without interference with the HPA axis.