bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cost‐effectiveness in Canada of intravenous proton pump inhibitors for all patients presenting with acute upper gastrointestinal bleeding
Authors: Enns R. A. , Gagnon Y. M. , Rioux K. P. , Levy A. R. 
Published: March 2003

SummaryBackground: The administration of proton pump inhibitors intravenously after endoscopic treatment of peptic ulcers significantly reduces the recurrence of bleeding.Aim: To evaluate the incremental cost‐effectiveness in Canada of intravenous proton pump inhibitor before endoscopic therapy to patients presenting with acute upper gastrointestinal bleeding, compared with endoscopic treatment alone.Methods: From a third‐party payer perspective, we modelled the costs and effectiveness over 60 days of the two approaches using decision analysis. The probabilities of various outcomes, such as re‐bleeding and the need for surgery, were taken from the published literature. We included the costs of intravenous proton pump inhibitor, therapeutic endoscopy, surgical procedures and hospitalizations, all expressed in 2001 Canadian dollars.Results: In a hypothetical cohort of 1000 patients, the intravenous proton pump inhibitor approach resulted in mean savings of $20 700 with 37 re‐bleeding episodes averted. The investigation of uncertainty resulted in a likelihood of intravenous proton pump inhibitor being cost‐effective of at least 0.73.Conclusion: It is common in Canada to administer intravenous proton pump inhibitors to patients with upper gastrointestinal bleeding even before endoscopic confirmation of bleeding peptic ulcers. Our results suggest that this approach has a high likelihood of being cost‐effective.
Patients with refractory Crohn's disease or ulcerative colitis respond to dehydroepiandrosterone: a pilot study
Authors: Andus T. , Klebl F. , Rogler G. , Bregenzer N. , Schölmerich J. , Straub R. H. 
Published: March 2003

SummaryBackground : Dehydroepiandrosterone is a steroid hormone used as an ‘over‐the‐counter’ drug in the USA. Treatment with dehydroepiandrosterone was effective in randomized controlled trials in patients with systemic lupus erythematosus. Dehydroepiandrosterone sulphate concentrations are decreased in patients with inflammatory bowel disease. Dehydroepiandrosterone inhibits nuclear factor‐κB and the secretion of interleukin‐6 and interleukin‐12 via the peroxisome proliferator‐activated receptor α.Aim : A phase II pilot trial was started to evaluate the effect of dehydroepiandrosterone in active inflammatory bowel disease.Methods : Twenty patients with chronic active inflammatory bowel disease [seven Crohn's disease (Crohn's disease activity index, 242 ± 51; mean ± s.d.); 13 ulcerative colitis (clinical activity index, 7.8 ± 2.1)] took 200 mg dehydroepiandrosterone per day orally for 56 days.Results : Six of the seven patients with Crohn's disease and eight of the 13 patients with ulcerative colitis responded to treatment, with a decrease in the Crohn's disease activity index of > 70 points and a decrease in the clinical activity index of > 4 points, respectively. Six Crohn's disease patients and six ulcerative colitis patients went into remission (Crohn's disease activity index < 150; clinical activity index ≤ 4). No patient withdrew from the study because of side‐effects.Conclusions : In a pilot study, dehydroepiandrosterone was effective and safe in patients with refractory Crohn's disease or ulcerative colitis. Adjustment of the dehydroepiandrosterone dosage may further improve the treatment success.
Gallstones — an increasing problem: a study of hospital admissions in England between 1989/1990 and 1999/2000
Authors: Kang J.‐Y. , Ellis C. , Majeed A. , Hoare J. , Tinto A. , Williamson R. C. N. , Tibbs C. J. , Maxwell J. D. 
Published: March 2003

SummaryBackground : The number of operations for cholelithiasis increased from the 1950s to the 1990s.Aims : To determine the time trends in cholelithiasis for hospital admissions, operations and in‐hospital case fatalities in England between 1989/1990 and 1999/2000, and population mortality rates between 1979 and 1999.Methods : Hospital Episode Statistics for admissions were obtained from the Department of Health and mortality data were obtained from the Office for National Statistics.Results : Between 1989/1990 and 1999/2000, age‐standardized hospital admission rates for cholelithiasis increased by 30% for males and 64% for females. The proportions of admissions undergoing an operation declined progressively over the study period. In 1999/2000, the frequency of operation was approximately 50–60% for most age groups, but decreased progressively with advancing age at ≥ 65 years. The proportions of admissions undergoing therapeutic endoscopy increased several‐fold, especially amongst older individuals. Case fatality rates declined. Mortality rates declined from 1979 to 1988, but showed no further change from 1989 to 1999.Conclusions : There has been a steady increase in admission rates for cholelithiasis over the study period. Whilst the frequency of operation has declined, the proportion of patients undergoing therapeutic endoscopy has increased.
Coagulation effects of in vitro serial haemodilution with a balanced electrolyte hetastarch solution compared with a saline‐based hetastarch solution and lactated Ringer's solution*
Authors: Roche A. M. , James M. F. M. , Grocott M. P. W. , Mythen M. G. 
Published: March 2003

SummaryThe hydroxyethyl starches are a group of compounds that has been associated with impairment of coagulation when large volumes are administered. The thrombelastograph® is commonly used to assess point‐of‐care whole blood coagulation. Little is known about the dose–response relationships of haemodilution, and it is reasonable to assume that a linear association exists. This may not be the case with altered electrolyte compositions of the fluids used for haemodilution. We have therefore conducted an in vitro study of haemodilution of human whole blood using lactated Ringer's solution and two high molecular weight hetastarches, one in a balanced salt solution, the other in a 0.9% saline solution. The thrombelastograph®, commonly used for the assessment of the coagulation effects of synthetic colloids, was used as the coagulation assessment device. Serial haemodilution with hetastarch in a balanced salt solution demonstrated a biphasic response (of r‐times and k‐times, as well as alpha angles), with haemodilution in the 20–40% range causing enhanced coagulation, and higher degrees of dilution causing a decrease in overall coagulation performance. A similar picture was observed with lactated Ringer's solution, but only significantly so in alpha angles. Hetastarch in saline did not display this initial increased coagulability at mild to moderate dilutions. This biphasic response of lactated Ringer's solution and hetastarch in a balanced salt solution reflects the complex interaction of fluids and the coagulation system, and that these effects cannot be attributed to simple haemodilution. On the other hand, there was a linear decrease in maximum amplitude with haemodilution. Maximum amplitude was particularly affected by both starches, which is an expected finding in view of the known interaction between the hydroxyethyl starches and von Willebrand's factor.
Patient‐controlled epidural fentanyl following spinal fentanyl at Caesarean section
Authors: Cooper D. W. , Garcia E. , Mowbray P. , Millar M. A. 
Published: March 2003

SummarySpinal fentanyl can improve analgesia during Caesarean section. However, there is evidence that, following its relatively short‐lived analgesic effect, there is a more prolonged spinal opioid tolerance effect. The effectiveness of postoperative epidural fentanyl analgesia may therefore be reduced following the use of spinal fentanyl at operation. This randomised, double‐blind study was designed␣to assess whether patient‐controlled epidural fentanyl could produce effective analgesia following 25 µg of spinal fentanyl at operation. Patients undergoing elective Caesarean section received spinal bupivacaine combined with either fentanyl 25 µg (fentanyl group; n = 18) or␣normal saline (saline group; n = 18). Patient‐controlled epidural fentanyl was used for postoperative analgesia. The fentanyl group used a mean of 23.4 (SD 14.5) µg.h−1 of fentanyl, compared with 27.0 (10.8) µg.h−1 for the saline group (p = 0.41). Using a 0–100 mm visual analogue score for pain, the maximum pain score recorded at rest for the fentanyl group was median 24 [IQR 15–35] mm, compared with 15 [13–45] mm for the saline group (p = 0.41). The maximum pain score recorded on coughing for the fentanyl group was 29 [24–46] mm, compared with 27 [19–47] mm for the saline group (p = 0.44). Nine of the fentanyl group rated postoperative analgesia as excellent and nine as good, compared with 10 of the saline group who rated it as excellent and eight as good (p = 0.74). Epidural fentanyl can produce effective analgesia following the use of 25 µg spinal fentanyl at Caesarean section.
Exhumation of the Pyrenean orogen: implications for sediment discharge
Authors: Morris  , Sinclair  , Yell  
Published: March 2003

Apatite fission track analyses of 21 samples from the central and eastern Pyrenees are modelled to generate time–temperature plots for the post 110±10 °C cooling history over the 40–10 Ma time interval. Modelled thermal histories have been converted into exhumation plots through the application of the present‐day geothermal gradient in the Pyrenees. The documented geology of the Pyrenees allows us to assume no significant extensional unroofing and subvertical exhumation trajectories, thus enabling exhumation to be translated into erosional denudation. Maps of denudation have been constructed for six, 5‐Myr time intervals. Denudation varied with a 20–50‐km length scale, and does not appear to have been related to the major structural zones of the mountain belt. Spatially averaged denudation rates for the six time intervals ranged from 34 to 61 mm kyr−1 assuming the present‐day geothermal gradient. Maximum rates of 240 mm kyr−1 occurred in the interval 35–30 Ma, in the region of the Querigut‐Millas massif.Assuming the denudation resulted primarily from erosion, the denudation maps can be used to calculate sediment discharge through time to the neighbouring foreland basins. Using a series of rectangular drainage basins with a 2:1 aspect ratio (based on modern linear mountain belts) and a location of the main drainage divide based on the mean present‐day position, it is possible to evaluate the potential for spatial and temporal variations in sediment discharge as a function of denudation. The results show along‐strike variations in sediment discharge between drainage basins of 500%, and temporal variations from individual basins of >300%. A comparison of total sediment discharge per year to the Ebro and Aquitaine basins, assuming a fixed drainage divide, shows that the discharge to the south is likely to have been between 1.5 and 2.8 times greater than to the north.
Sediment supply from landslide‐dominated catchments: implications for basin‐margin fans
Authors: Allen Philip A. , Hovius* Niels 
Published: March 2003

The sediment flux from a mountainous catchment can be expressed as a function of a landslide rate constant κ which accounts for the vigour of hillslope erosion. Since the incising drainage network flushes all or a portion of the products of hillslope erosion to a range front where fan deposition takes place, a conservation of solid sediment volume allows the fan area and progradation distance to be calculated. These parameters are related primarily to the discharge of sediment from the catchment and to local tectonic subsidence.A survey of modern alluvial fans in a wide range of climatic and tectonic settings shows that the effects of climate and bedrock lithology cannot be discriminated in the scatter of data of catchment area vs. fan area. However, by focusing on over 100 fans in the arid and semiarid zone of SW USA, the impact of tectonic subsidence rate is unambiguous. Although further quantitative data on local tectonic subsidence rates are urgently required, our preliminary analysis suggests considerable potential for reconstructing palaeocatchments where basin tectonic subsidence rates can be estimated. The progradation distances of fans from the northern and southern margins of the Middle Devonian Hornelen Basin of Norway, and the western and north‐eastern margins of the Mio‐Pliocene Ridge Basin, California, allow catchment sizes and denudation rates to be approximated. Although unique solution sets are not possible, an iteration of parameter values allows plausible parameter combinations to be calculated which shed light on the tectonic and sedimentary history of the proximal basin and upland source regions. Model results suggest significant asymmetry in basin subsidence rates, catchment slopes and transport mechanics between the two margins.
Erosion, deposition and basin‐wide variations in stream power and bed shear stress
Authors: Talling Peter J. , Sowter Matthew J. 
Published: March 2003

Field data from four separate locations indicate that the rate at which river channel gradient decreases downstream is fundamentally different in areas of long‐term erosion and deposition. Gradient (S) and distance from the drainage divide (x) are related such that S is proportional to xφ. In areas of deposition φ<−3, whilst in areas of erosion φ>−1.1. These differences produce downstream increases and decreases in stream power and bed shear stress which also coincide with areas of erosion and deposition. This is the first time that such a basin‐wide coincidence has been demonstrated.A strong positive correlation between stream power, bed shear stress and bedload transport rates has been clearly shown by previous empirical studies of loose‐bed channels. It is proposed that large‐scale patterns of erosion and deposition in alluvial basins result from downstream changes in bedload transport rates, produced by the observed trends in these two parameters. If this proposal is to be fully tested, further work is needed to assess the affects of downstream fining of bed material, short‐term fluctuations in discharge and downstream exchange of particles between the suspended load and bedload.
Seismic stratigraphy of the Miocene–Pleistocene sedimentary basins of the Northern Tyrrhenian Sea and western Tuscany (Italy)
Authors: Pascucci  , Merlini  , Martini  
Published: March 2003

Seismic and stratigraphic data of the inland Volterra Basin and of the Tuscan Shelf (Northern Tyrrhenian Sea) have been analysed to determine the tectono‐sedimentary evolution of this part of the Northern Apennines from the early Miocene (about 20 Ma) to the present. The area is a good example for better understanding the evolution of postcollisional related basins.The study area is characterized by a series of sedimentary basins separated by tectonic ridges. Similar environmental conditions existed both onshore and offshore as indicated by the occurrence of similar seismic units. The units are separated by major unconformities. The cross‐sectional geometries of the deposits of these basins, as defined through seismic reflection profiles, change in a quasi‐regular manner through time and space.Early stages (late Burdigalian to early Tortonian) of evolution of the basins are marked by either flat‐lying deposits, quasi‐uniform in thickness, probably remnants of originally wider and shallow settings, or, in places, by relatively small bowl‐shaped basins. The latter may have been strongly affected by the pre‐existing topography and tectonics, as they developed at or near the leading edges of pre‐Neogene substrate thrusts. These early deposits represent sedimentation during a transitional period from the end of compressional tectonics to the start of an extensional phase and represent a pre‐narrow rift stage of evolution of the region. The subsequent stage of tectonic evolution (late Tortonian to early Messinian), where preserved, is recorded by fault‐bounded triangular‐shaped basins interpreted as half‐grabens. This is one of the periods of major development of narrow rifts in the area. The following stage (late Messinian to Early Pliocene) is marked by variable types of basins, showing wide and deep bowl‐shaped geometries persistent in the offshore, whereas inshore (Volterra Basin) they alternate with half‐graben, synrift deposits. This period thus represents a transitional stage where part of the system is still affected by synrift sedimentation and part is developing into incipient post‐rift conditions. This stage was followed in early to middle Pliocene times by wide bowl‐shaped to blanket‐type deposits both in offshore and in inshore areas, indicating regional post‐rifting conditions. The pre‐, syn‐ and post‐rift stages have followed each other through time and space, starting first in the westernmost offshore area and shifting later toward the east, inshore.
Multiphase cooling and exhumation of the southern Adelaide Fold Belt: constraints from apatite fission track data
Authors: Gibson H. J. , Stüwe K. 
Published: March 2003

Data from apatite fission track analysis are presented for 20 outcrop samples collected in the southern Adelaide Fold Belt, South Australia. Interpretation of these data, with the aid of numerical models which allow inference of multiphase cooling histories, indicate three discrete cooling events that are likely to correlate with sedimentation events in surrounding depositional settings. An event beginning some time after 85 Ma (Late Cretaceous) was characterized by cooling throughout the study area from temperatures of roughly 50 to 70 °C. An event beginning at 300–270 Ma (Late Palaeozoic) was characterized by cooling from temperatures >120 °C in all areas except for the Mount Lofty Ranges and Murray Bridge region, where peak temperatures were only 95–115 °C prior to Palaeozoic cooling. Some samples from these subregions of relatively cool Late Palaeozoic temperatures also retain evidence for even earlier cooling from temperatures >120 °C, beginning prior to 350 Ma. We interpret the post 85‐Ma event as the consequence of regional exhumation from a depth of 1.0–1.6 km. The Late Palaeozoic event (300–270 Ma) is interpreted as cooling associated with the termination of the Alice Springs Orogeny, while cooling prior to 350 Ma probably represents the final stages of Early Middle Palaeozoic unroofing of the southern Adelaide Fold Belt.The results highlight the importance of regional, episodic postorogenic exhumation of Palaeozoic fold belts, where – in some cases – conventional methods have erroneously suggested relatively long‐term stability.
The Western Irish Namurian Basin reassessed
Authors: Wignall P. B. , Best J. L. 
Published: March 2003

ABSTRACT Current basin models for the Western Irish Namurian Basin (WINB) envisage an elongate trough along the line of the present‐day Shannon Estuary that was infilled with clastic sediments derived from a hinterland that lay to the W or NW. This paper argues for an alternative basin configuration with source areas to the SW supplying sediment to a basin where deepest water conditions were in northern County Clare. Rapid subsidence along the present‐day Shannon Estuary ponded sediment in this area throughout the early Namurian and, only with the rapid increase of sedimentation rates within the mid‐Namurian (Kinderscoutian Stage), were substantial amounts of sediment able to prograde to the NE of the basin. This alternative model better explains the overwhelming predominance of NE‐directed palaeocurrents in the Namurian infill, but requires fundamental revisions to most aspects of current depositional models.Deep‐water black shales (Clare Shale Formation) initially accumulated throughout the region and were progressively downlapped by an unconfined turbidite system (Ross Formation) prograding to the NE. This in turn was succeeded by an unstable, siltstone‐dominated slope system (Gull Island Formation) characterized by large‐scale soft‐sediment deformation, which also prograded to the NE. In the northern‐most basin outcrops, in northern County Clare, this early phase of basin infill was developed as a condensed succession of radiolarian‐rich black shales, minor turbiditic sandstones and undisturbed siltstones. The new basin model envisages the northern exposures of County Clare to be a distal, basin floor succession whereas the traditional model considers it a relatively shallow, winnowed, basin margin succession. Later stages of basin infill consist of a series of deltaic cycles that culminate in major, erosive‐based sandstone bodies (e.g. Tullig Sandstone) interpreted either as axial, deltaic feeder channels or incised valley fills genetically unrelated to the underlying deltaic facies. Within the context of the new basin model the former alternative is most likely and estimated channel depths within the Tullig Sandstone indicate that the basal erosive surface could have been generated by intrinsic fluvial scour without recourse to base‐level fall. The northerly flowing Tullig channels pass down‐dip into isolated channel sandbodies interbedded with wave‐dominated strata that suggest the deltas of the WINB were considerably more wave‐influenced than hitherto proposed. The retreat of the Tullig delta during sea‐level rise saw the rapid southerly retrogradation of parasequences, as may be expected if the basin margin lay to the SW of the present‐day outcrops.