bluuebunny/crossref_metadata_2025 huggingface dataset:
Stratigraphic architecture and depositional setting of the coarse‐grained Upper Cambrian Owen Conglomerate, West Coast Range, western Tasmania
Authors: Noll C. A. , Hall M.
Published: January 2004

The Upper Cambrian Owen Conglomerate of the West Coast Range, western Tasmania, comprises two upward‐fining successions of coarse‐grained siliciclastic rocks that exhibit a characteristic wedge‐shaped fill controlled by the basin‐margin fault system. Stratigraphy is defined by the informally named basal lower conglomerate member, middle sandstone member, middle conglomerate member and upper sandstone member. The lower conglomerate member has a gradational basal contact with underlying volcaniclastics of the Tyndall Group, while the upper sandstone member is largely conformable with overlying Gordon Group marine clastics and carbonates. The lower conglomerate member predominantly comprises high flow regime, coarse‐grained, alluvial‐slope channel successions, with prolonged channel bedload transport exhibited by the association of channel‐scour structures with upward‐fining packages of pebble, cobble and boulder conglomerate and sandstone, with abundant large‐scale cross‐beds derived from accretion in low‐sinuosity, multiply active braided‐channel complexes. While the dipslope of the basin is predominantly drained by west‐directed palaeoflow, intrabasinal faulting in the southern region of the basin led to stream capture and the subsequent development of axial through drainage patterns in the lower conglomerate member. The middle sandstone member is characterised by continued sandy alluvial slope deposition in the southern half of the basin, with pronounced west‐directed and local axial through drainage palaeoflow networks operating at the time. The middle sandstone member basin deepens considerably towards the north, where coarse‐grained alluvial‐slope deposits are replaced by coarse‐grained turbidites of thick submarine‐fan complexes. The middle conglomerate member comprises thickly bedded, coarse‐grained pebble and cobble conglomerate, deposited by a high flow regime fluvial system that focused deposition into a northern basin depocentre. An influx of volcanic detritus entered the middle conglomerate member basin via spatially restricted footwall‐derived fans on the western basin margin. Fluvial systems continued to operate during deposition of the upper sandstone member in the north of the basin, facilitated by multiply active, high flow regime channels, comprising thick, vertically stacked and upward‐fining, coarse‐grained conglomerate and sandstone deposits. The upper sandstone member in the south of the basin is characterised by extensive braid‐delta and fine‐grained nearshore deposits, with abundant bioturbation and pronounced bimodal palaeocurrent trends associated with tidal and nearshore reworking. An increase in base‐level in the Middle Ordovician culminated in marine transgression and subsequent deposition of Gordon Group clastics and carbonates.
Revised geochronology of magmatism in the western Capricorn Orogen at 1805–1785 Ma: diachroneity of the Pilbara–Yilgarn collision
Authors: Evans D. A. D. , Sircombe K. N. , Wingate M. T. D. , Doyle M. , McCarthy M. , Pidgeon R. T. , Van Niekerk H. S.
Published: January 2004

The June Hill Volcanics occupy a central stratigraphic position in the tectonic evolution of the Capricorn Orogeny that occurred along the southwestern margin of the Pilbara Craton in Palaeoproterozoic time. The volcanic rocks have been interpreted alternatively as due to continental rifting, foreland‐basin development, or backarc extension. Previous multigrain zircon U–Pb results from these rocks, as well as from an unnamed rhyolitic porphyry that is interstratified in turbidites of the overlying Ashburton Formation, are influenced by the combined effects of Pb loss and xenocrystic inheritance. We report new SHRIMP zircon ages of 1799 ± 8 and 1786 ± 11 Ma, respectively from the June Hill Volcanics and the unnamed porphyry, both of which have been deformed during the Capricorn Orogeny. Close similarity between these ages and results from various late‐stage Capricorn granitoids (including our new SHRIMP result of 1795 ± 8 Ma for the Minnie Creek granite) imply rapid development of the western Ashburton Trough, accumulating and deforming ∼10 km of turbiditic sediments in about 10 million years. Comparison of our new June Hill age with previous SHRIMP results from the central Ashburton Trough implies that foreland‐basin development of the Capricorn Orogeny was significantly diachronous, younging westward during oblique Pilbara–Yilgarn convergence.
Carboniferous palaeomagnetism of the Werrie Block, northwestern Tamworth Belt, and the New England pole path*
Authors: Klootwijk C. T.
Published: January 2004

Palaeomagnetic, rock‐magnetic and magnetic‐fabric results are presented for Carboniferous and Lower Permian volcanic and volcaniclastic rocks (Merlewood Formation, Currabubula Formation, Werrie Basalt and Boggabri Volcanics), mainly from the Werrie Block of the northwestern Tamworth Belt, southern New England Orogen. Detailed thermal demagnetisation results (91 sites, 998 samples) show two groups of magnetic components with low (<400°C; LT) and high (500–700°C; HT) unblocking temperature ranges. Rock magnetic tests indicate the HT components to reside in magnetite, with single or pseudo‐single domain and multidomain characteristics, and in hematite. Detailed demagnetisation up to 700°C demonstrates subtle directional differences between primary components, optimally cleaned and derived from the magnetite–hematite carrier (HT‐P2), and pseudo‐components, incompletely cleaned and derived from the mainly magnetite carrier (HT‐P1). Directional results evidence three phases of magnetic overprinting which arose from: (i) a possible Middle–Late Cenozoic regional weathering event (LT); (ii) fluid movements associated with the Permo‐Triassic Hunter–Bowen Orogeny (HT); and (iii) formation of the Bowen–Gunnedah–Sydney Basin system in the latest Carboniferous – Early Permian (HT). Magnetic fabric results show the Kmax and Kmin axes of the susceptibility anisotropy ellipsoids to better concentrate in stratigraphic than in geographical (in situ) coordinates, suggesting a primary depositional pattern. The prevailing north–south alignment of Kmax axes changes to east–west towards the top of the Currabubula Formation. The sense of transport could not be established in absence of evidence for imbrication. Well‐defined primary magnetisation components (HT‐P2) have been determined for 39 of the 69 Currabubula Formation sites and for all sites of the Merlewood Formation (7), Werrie Basalt (9) and Boggabri Volcanics (6). Currabubula Formation site results have been combined into three mean‐site results, all with positive fold tests at the 99% confidence level. They show good agreement with correlatable results from the northward adjacent Rocky Creek Block. Integration of the palaeomagnetic poles for the Currabubula Formation and a virtual geomagnetic pole for the Merlewood Formation with earlier determined Visean to Westphalian poles for the Rocky Creek Block outlines a Visean (Tournaisian?) to Stephanian pole path for the northwestern Tamworth Belt. Comparison with a preliminary pole path for the Rouchel and western Gresford Blocks shows no evidence for significant rotational deformation between the northwestern and southwestern Tamworth Belt. Comparison with the Northern Hastings Block indicates counterclockwise rotation of the latter relative to the northwestern Tamworth Belt over about 150°, in agreement with structural estimates.
Geochemistry and tectonic settings of meta‐igneous rocks in the Arthur Lineament and surrounding area, northwest Tasmania*
Authors: HOLM O. H. , CRAWFORD A. J. , BERRY R. F.
Published: January 2004

The Arthur Lineament is a Cambrian age high‐strain metamorphic belt that transects northwestern Tasmania and forms the eastern margin of the Mesoproterozoic and Neoproterozoic Rocky Cape Block. It formed as a result of Middle Cambrian arc–continent collision, and is composed of both allochthonous slices (Bowry Formation and Reece amphibolite), the para‐autochthonous ‘eastern’ Ahrberg Group and the autochthonous ‘western’ Ahrberg Group. Amphibolites and mafic schists of the ‘eastern’ Ahrberg Group rocks show a temporal change in composition from transitional alkaline basalt to dominant E‐MORB‐type rift tholeiites, whereas the ‘western’ Ahrberg Group metabasic rocks are typical E‐MORB rift tholeiites. The lithostratigraphy of the Ahrberg Group matches very well that of the Upper Neoproterozoic (650–580 Ma) Togari Group of the Smithton Trough and King Island. In contrast, amphibolites of the allochthonous Bowry Formation, which also show E‐MORB‐type patterns typical of rift‐type tholeiites, are intruded by granitoid sheets dated at 777 ± 7 Ma, similar to the Precambrian granites exposed on King Island (760 ± 12 Ma). The Bowry Formation granitoids have distinctive high Ti, Zr, Nb compositions best matched by granites produced by extended fractionation of rift basalts with significant crustal assimilation. This suggests that the Bowry Formation metabasic rocks may correlate with the Willouran flood basalts in South Australia, and together record theca780 Ma breakup event hypothesised to mark the breakup of the Rodinian supercontinent
Evolution of beach placer shorelines and heavy‐mineral deposition in the eastern Eucla Basin, South Australia
Authors: HOU B. , FRAKES L. A. , ALLEY N. F. , HEITHERSAY P.
Published: January 2004

The eastern Eucla Basin of South Australia has potential as a world‐class heavy‐mineral sand province. Heavy‐mineral sampling has provided a vector to such deposits, but there is debate about the distribution and evolution of heavy‐mineral deposits. Several cycles of marine transgression have left generations of beach placer concentrations buried beneath the present landscape of the eastern Eucla Basin. Evidence from boreholes, compilation of stratigraphic records and analysis of the palaeogeographical evolution assist in defining a number of Tertiary shorelines. Concentrations of detrital rutile, zircon, ilmenite, and minor leucoxene and monazite occur as beach placers in highstand barriers and dunes of Tertiary age along these shorelines. The most prospective strata are the barrier and associated sandstones of Tertiary shorelines that were buried by voluminous sand dunes at over 40 Ma. The geographical and stratigraphic distributions of heavy‐mineral‐bearing sandstone in Tertiary sediments suggest contemporaneous transport through palaeovalleys predominantly from Precambrian cratons.
Diamonds of multiple origins from New South Wales: further data and discussion
Authors: SUTHERLAND F. L. , BARRON L. M.
Published: January 2004

Diamonds from Brickclay Creek, near Walcha, are associated with a Cenozoic nephelinitic intrusion and expand evidence for multiple origins for diamonds from New South Wales. Although the diamonds show similar morphology and C‐isotope characteristics to the unusual subduction‐related diamonds from the Bingara–Copeton fields, the greater topographic elevation of the associated rocks, and particularly the N aggregation relationships of the diamonds indicate a separate local source. Both yellow and white diamonds from Walcha show limited 1aB nitrogen aggregation (0–7%), similar to that of Ellendale 4 diamonds from Cenozoic pipes in Western Australia. A model is proposed for their local origin from a relatively young (Mesozoic?) subducted mantle slab below the eastern New England Orogen.
Aspects of the structural and late thermal evolution of the Redbank Thrust system, central Australia: constraints from the Speares Metamorphics
Authors: Biermeier C. , Wiesinger M. , Stüwe K. , Foster D. A. , Gibson H. J. , Raza A.
Published: January 2004

We present new data on the field geology and late thermal evolution of the Redbank Thrust system in the Arunta Block of central Australia. Geochronological and field data from the Speares Metamorphics are also used to relate the thermal evolution of the Redbank Thrust system to the structural evolution of the region. We show that several stages in the evolution might be discerned. An originally sedimentary sequence was intruded by mafic intrusions and then deformed during partial melting to form the principal foliation observed in the region (D1). This sequence was then folded during D2 into upright folds with north‐ to northeast‐plunging fold axes. These events are likely to correlate with the Strangways and/or Argilke and Chewings Orogenies known from previous studies. Subsequently, the Redbank Thrust was initiated during D3. This event is recognised by deflection of the host rocks into the shear zone and might therefore have been associated with a component of strike‐slip motion. It occurred probably at or before 1500–1400 Ma. Subsequent north‐over‐south thrust motion in the Redbank Thrust formed the intense mylonitic fabric and folded the mylonitic fabric during D4 into asymmetric folds with shallow fold axes. New40Ar/39Ar K‐feldspar ages from three samples collected from variably deformed branches of the Redbank Thrust and undeformed rocks in the Speares Metamorphics suggest that most parts of the Redbank Thrust system cooled relatively slowly after metamorphism and deformation in the Mesoproterozoic so that the D4 thrusting might have been very long‐lived. Minimum ages of the K‐feldspar age spectra show that the entire region cooled below 200°C by approximately 300 Ma. Apatite fission track ages from nine samples show that cooling through the apatite partial annealing zone occurred during Cretaceous time (ca150–70 Ma) and modelled cooling histories are consistent with the cooling rates obtained from the K‐feldspar data. They indicate that final exhumation of the Redbank Thrust system occurred probably in response to erosion, possibly driven by rifting around the margins of Australia.
Evolution of the boundary between the western and central Lachlan Orogen: implications for Tasmanide tectonics
Authors: Spaggiari C. V. , Gray D. R. , Foster D. A. , McKnight S.
Published: January 2004

Differences in oblique overprinting, along‐strike complexity as well as structural, metamorphic and timing constraints suggest that the boundary between the western and central subprovinces of the Lachlan Orogen, currently designated by the Governor Fault, cannot be a single structure. Previously limited data on the nature and kinematics of the fault/shear systems defining the boundary have led to varying scenarios for the tectonic evolution of the Lachlan Orogen. These scenarios either involve large‐scale strike‐slip displacement along the boundary with subsequent overthrusting or convergence of oppositely vergent thrust‐systems with limited strike‐slip translation. Geometrical constraints, fabric chronology and kinematic indicators in both the Mt Wellington (Melbourne Zone) and Governor (Tabberabbera Zone) Fault Zones indicate that maximum displacements relate to thrusting and duplex formation, followed by minor strike‐slip faulting perhaps in response to slightly oblique collision of the Melbourne and Tabberabbera structural zones. Collision of these zones took place betweenca400 and 390 Ma. At Howqua, structural relationships indicate that collision involved northeast‐directed thrusting of the Melbourne Zone (Mt Wellington Fault Zone) over the Tabberabbera Zone (Governor Fault Zone), and was followed by regional, northwest‐trending, open folding. These structures overprint the dominant fabrics and metamorphic assemblages that are interpreted to relate to disruption and underthrusting of Cambrian oceanic/arc crust during closure of a marginal basin. Major deformation in the Tabberabbera Zone took place fromca445 Ma and was associated with mélange formation, underplating and imbrication or duplexing (Governor Fault Zone, East Howqua segment). At slightly higher crustal levels, and following deposition of Upper Ordovician black shale and chert sequences (ca440 Ma), Tabberabbera Zone evolution included offscraping of a serpentinite body (Dolodrook segment) that may have been either a Marianas‐style seamount or transform fault zone within the Cambrian oceanic/arc crust. Major thrusting in the Mt Wellington Fault Zone was underway sometime afterca420 Ma, and in contrast to the Governor Fault Zone, no mélange or broken formation was produced, metamorphism was at slightly higher temperatures and deformation probably occurred under higher strain states.
Carbon dioxide and water vapor exchange over a Miscanthus‐type grassland: Effects of development of the canopy
Authors: Li Sheng‐Gong , Lai Chun‐Ta , Yokoyama Tomoko , Oikawa Takehisa
Published: January 2004

The eddy correlation technique was employed to measure net ecosystem carbon dioxide (CO2) (NEE) and water vapor exchange (LE) over a C3/C4 co‐occurring wet temperate Miscanthus‐type grassland in the Kanto plain of Japan in the 1999 growing season. The maximal mean canopy height and maximal leaf area index were 1.0 m and 5.5, respectively. The daily maximal LE was approximately 540 W m−2. The maximum value of daily accumulative LE was 16.3 MJ day−1. Daily variation of the decoupling factor (Ω) suggests that in the morning LE decoupled with the atmosphere, and the available energy was the major driving force for LE, whereas in the afternoon LE coupled strongly with the atmosphere, and the atmospheric evaporative demand played a critical role in LE. The decline in Ω (from 0.8 to 0.5) with the growing season demonstrates that LE decoupled from the atmosphere in the later growth season. The peak NEE value was 57.4 µmol CO2 m−2 s−1 (the positive value signifies the canopy carbon gain was from the air). The maximal daily integrated NEE was 1.06 mol CO2 m−2 day−1 observed during the peak growth stage. A rectangular hyperbolic model was used to describe the relation between daytime NEE and incident photosynthetic photon flux density (PPFD). The net ecosystem CO2 was not light‐saturated up to a PPFD level of 2000 µmol m−2 s−1. The initial slope estimated with the NEE–PPFD response model was approximately 0.042 mol CO2 mol−1 photon on average. The canopy light compensation point ranged from 210 to 430 µmol m−2 s−1 with an average of approximately 310µmol m−2 s−1. Both the initial slope and the canopy light compensation point decreased as the canopy senesced. The switch in dominance from C3 to C4 plants played an important role in the canopy fluxes.
Community‐level flowering phenology and fruit set: Comparative study of 25 woody species in a secondary forest in Japan
Authors: Osada Noriyuki , Sugiura Shinji , Kawamura Koji , Cho Michiko , Takeda Hiroshi
Published: January 2004

We investigated the flowering phenology, pollinator visitation, and fruit set of 25 animal‐pollinated woody species in a warm temperate secondary forest in Japan. Various species flowered sequentially from February to October. The principal pollinators were bumblebees, honey‐bees, flies and/or beetles and birds; bumblebees and flies/beetles pollinated most trees. The duration of flowering was shorter for species that bloomed in the middle of the season than it was for species that bloomed earlier or later in the season. The timing of flowering was more synchronous within species that had a shorter flowering duration; this was also detected when phylogenetically independent contrasts were calculated. This could be important for the effective pollination of species with a short flowering duration because such species bloom sequentially over a short period of less than 1 month around May. Fruit set was related not to pollinator type, sex expression, flowering sequence (in order of the date of peak flowering) or flowering duration, but to the relative abundance of the species in the forest. This correlation was detected for fly‐ and beetle‐pollinated species but not for bumblebee‐pollinated species. Thus, relatively rare plant species with opportunistic pollinators might experience limited fruit set because of insufficient pollinator services. Bagging experiments conducted on eight hermaphrodite species revealed that the fruit set of bagged flowers was nearly zero, lower than that of control flowers. These results indicate the importance of pollinators for successful reproduction and thus for the coexistence of plants in this secondary forest.
Floral morph composition and pollen limitation in the seed set of Nymphoides indica populations
Authors: Shibayama Yuki , Kadono Yasuro
Published: January 2004

We investigated the floral morph composition and seed set of the populations in a heterostylous aquatic plant, Nymphoides indica O. Kuntze (Menyanthaceae). The bias of floral morph ratio in the populations was negatively correlated with the seed set. In the populations with biased floral morph ratio, the pollen on the stigma of the common morphs were dominated by pollen of the same morph, resulting in reduced seed set. The addition of pollen of the opposite morph on the stigmas of the common morph resulted in an increase of fruit and seed set rates. The intermorph pollination rate and the fruit and seed set rates of Nymphoides indica were highest when two floral morphs were close in the populations. Various insect species including Lepidoptera, Diptera and Hymenoptera visited the flowers. However, geitonogamous pollination was common because of the short flying distance of the pollinators. These results indicate that the seed set of Nymphoides indica is limited by the shortage of compatible pollens and that the success of intermorph pollination is influenced by spatial distribution of the two floral morphs. As Nymphoides indica is endangered, conservation of the populations with high fecundity is proposed by us.
Vegetation patterns and their dependency on site conditions in the pre‐industrial landscape of north‐eastern Japan
Authors: Osumi Katsuhiro , Ikeda Shigeto , Okamoto Toru
Published: January 2004

We reconstructed the vegetational landscape of the pre‐industrial era (the beginning of the twentieth century) in north‐eastern Japan, and estimated the distribution patterns of traditional land‐uses, as suggested from the vegetation. We found significant correspondence between the spatial patterns of vegetational landscape and site attributes, and hypothesized the underlying mechanisms. The study area was classified into three vegetation types: grasslands, secondary forests and old‐growth forests. It was determined that the grasslands were formed and maintained by burning; secondary forests were derived from either charcoal woods or forests recovered on abandoned grasslands; and old‐growth forests had suffered the least anthropogenic disturbance. Each past vegetation type showed significant dependency on site attributes such as altitude, slope angle, slope aspect, hydrological topography and distance from the nearest human habitation. The relative importance of these site attributes varied depending on the vegetation type. Grasslands and old‐growth forests, which were the most and the least disturbed sites in the study area, respectively, showed clear contrasts in their dependencies especially on the slope aspect and on elevation. These site attributes were thought to have had influences on each vegetation type by determining the inflammability of the site. Satellite photographs indicated that north‐facing valleys had been relatively wet throughout the fire‐prone spring season. Hence, these areas would have been free from frequent fire, and more likely to preserve old‐growth forests. Ground wetness in spring was thought to be the underlying factor determining the contrasts in past vegetation and land‐use patterns in the area.
Effects of understory dwarf bamboo on soil water and the growth of overstory trees in a dense secondaryBetula ermaniiforest, northern Japan
Authors: Takahashi Koichi , Uemura Shigeru , Suzuki Jun‐Ichirou , Hara Toshihiko
Published: January 2004

The effects of understory dwarf bamboo (Sasa kurilensis) on soil water and the growth of overstory trees were studied in a dense secondary forest ofBetula ermaniiin northern Japan. Four plots were established in aBetula ermaniiforest withSasa kurilensisin the understory. TheSasawas removed in two of the plots. The annual increment of the trunk diameter for each tree was measured in the first two years from the commencement of the experiment. Soil water potential was similar in the plots following significant rainfall, but was found to be greater in the plot withoutSasabetween rainfall events. This suggests that the removal ofSasaslows the reduction of soil water after rainfall. The relative growth rate of the trunk diameter ofBetula ermaniiincreased with tree size in all of the plots because taller trees strongly suppressed smaller ones in the dense forest. The growth rates ofBetula ermaniiwere higher in the plots withoutSasa. However, the difference in growth rates between all of the plots tended to be smaller in smaller size classes, possibly because smaller trees were strongly suppressed by larger ones, irrespective of the presence/absence ofSasa. Therefore, the removal ofSasaincreased soil water and encouraged the growth of largerBetula ermaniiin dense forest during the first two years after theSasawas removed. The present study suggests thatSasacan reduce the growth of largerBetula ermaniiin dense forest by limiting available soil water to these trees.
Food habits of sambar Cervus unicolor at the Horton Plains National Park, Sri Lanka
Authors: Padmalal U.K.G.K. , Takatsuki Seiki , Jayasekara Palitha
Published: January 2004

The sambar Cervus unicolor has a large population in southern Asia. In Sri Lanka, its habitat use is most common among the four cervid species. We carried out an analysis of the food habits of sambar in the Horton Plains National Park from January to November 1991 by using the quantitative fecal analysis method. Analyses of sambar feces collected at the three habitats (two grassland communities and a forest) in the Horton Plains National Park found that the sambar diet largely consisted of graminoid leaves; 45–78% in grasslands and 43–60% in the forest. The analyses also found that the proportion of graminoid leaves in early summer (52–78%) was greater than it was in winter (43–49%). In spring and summer, different varieties of graminoids were consumed by sambar, whereas dicotyledonous plants were consumed in winter. The fecal nitrogen level did not fall below the critical level of their nutrition (1.1%), indicating that sambar food quality in the Horton Plains was sufficient. A large proportion of Pennisetum spp., exotic grasses (10–39%) were found in the fecal compositions collected in the Pennisetum community. This could be because of the high biomass and high nitrogen concentration (approximately 2.4%) of Pennisetum and its low‐growing nature. From the present study, we found that in order for sambar, a native ungulate, not to increase in number, the growth of exotic plants such as Pennisetum needs to be controlled.
Effects of fish chemical cues on tadpole survival
Authors: Takahara Teruhiko , Kohmatsu Yukihiro , Maruyama Atsushi , Yamaoka Ryohei
Published: January 2004

The indirect effects of goldfish chemical cues on tadpole survival and predation by other predators (e.g. dragonfly nymph and crayfish) were tested in a field experiment. Fish chemical cues were found to affect tadpole survival when dragonfly nymphs were present. In contrast, this indirect effect was not detected in the presence of crayfish. The results from the present study found that predators, even without predation, can affect the predatory efficiency of other predators, and that the degree of such an indirect effect may differ among the foraging strategies of predators.
Paraduodenal hernia and jejunal diverticulosis
Authors: GOODNEY PHILIP P , PINDYCK FRANK
Published: January 2004

Abstract  A case of left‐sided paraduodenal hernia and jejunal diverticulosis is described in 75‐year‐old man who presented with chronic intermittent abdominal pain, weight loss, and anemia. A brief review of the epidemiology, pathogenesis, and clinical presentation displays the variety of symptoms associated with these rare conditions.
Lactobacillus plantarum 299: Beneficial in vitro immunomodulation in cells extracted from inflamed human colon
Authors: PATHMAKANTHAN SHRI , LI CHRIS KF , COWIE JONATHAN , HAWKEY CHRISTOPHER J
Published: January 2004

Background and Aim:  The present study determined the pattern of cytokine secretion (interleukin [IL]‐1β, tumor necrosis factor [TNF]‐α, interferon [IFN]‐γ and IL‐10) and their cellular sources in mononuclear cells isolated from colonic mucosa from normal and ulcerative colitis (UC) in response to probiotic and pathogenic bacteria.

Methods:  Mononuclear cells were extracted from normal and active UC colonic mucosa and incubated with pure sonicates of probiotic, commensal, and pathogenic bacteria. Cytokine secretion was measured in culture supernatant and intracellular cytokine staining measured using fluorescent‐activated cytometry.

Results:  In mononuclear cells isolated from normal mucosa, significant increases in mean IL‐1β were observed with enteropathogenic Escherichia coli (286.3 ± 138.7 pg/mL P < 0.05) and E. coli (440.5 ± 194.0 pg/mL P < 0.01) compared with unstimulated control cells (16.7 ± 4.8 pg/mL). In contrast, mononuclear cells isolated from active UC mucosa produced significant increases in mean IL‐1β in response to stimulation with Salmonella dublin (230.5 ± 38.8 pg/mL P < 0.05), enteropathogenic E. coli (231.7 ± 45.3 pg/mL P < 0.05) and E. coli (465.4 ± 60.2 pg/mL P < 0.001) compared with unstimulated control cells (60.7 ± 17.1 pg/mL). Escherichia coli also produced significant mean increases of  TNF‐α and IFN‐γ compared with unstimulated control cells. No significant increases in IL‐1β, TNF‐α or IFN‐γ were observed with Lactobacillus plantarum in cells derived from normal or inflamed mucosa. Strikingly, incubation of L. plantarum with mononuclear cells isolated from active UC mucosa resulted in significant increases of mean IL‐10 (327 ± 53.5 pg/mL, P < 0.05) compared with unstimulated control cells (29.7 ± 13.2 pg/mL). Intracellular cytokine staining confirmed T‐cell and macrophage IL‐10 production after L. plantarum stimulation.

Conclusions:  Lactobacillus plantarum demonstrates beneficial immunomodulatory activity by increasing IL‐10 synthesis and secretion in macrophages and T‐cells derived from the inflamed colon. This may provide a mechanism through which probiotic bacteria ameliorate inappropriate inflammation and induce tolerance.
Hepatitis E superinfection produces severe decompensation in patients with chronic liver disease
Authors: RAMACHANDRAN JEYAMANI , EAPEN CE , KANG GAGANDEEP , ABRAHAM PRIYA , HUBERT DARIUS DJ , KURIAN GEORGE , HEPHZIBAH JULIE , MUKHOPADHYA ASHIS , CHANDY GEORGE M
Published: January 2004

Background and Aims:  The adverse effect of acute hepatitis A in chronic liver disease is well known. The outcome of acute hepatitis E in chronic liver disease has not been extensively studied. The present study aimed to examine the clinical profile and outcome of patients with chronic liver disease and hepatitis E virus (HEV) superinfection, and the seroprevalence of hepatitis A and E infections in patients with chronic liver disease and controls in India.

Methods:  A retrospective study of patients with chronic liver disease and acute icteric hepatitis E was performed. Acute hepatitis E was diagnosed by immunoglobulin (Ig)M ELISA. Seroprevalence studies were carried out using IgG ELISA in 100 patients with chronic liver disease and 79 age‐ and sex‐matched controls.

Results:  From June 2001 to December 2002, nine patients with chronic liver disease were found to have superinfection with HEV. Out of these, six patients died of advanced liver failure. The etiology of liver disease was Wilson's disease in six, hepatitis B virus in one, autoimmune in one and cryptogenic in one case. The seroprevalence of hepatitis A was 99 and 100% and 56 and 21% for HEV in cases and controls, respectively.

Conclusions:  Acute HEV in patients with chronic liver disease has a grave prognosis. Wilson's disease was the most common cause of chronic liver disease complicated by acute HEV. Seroprevalence studies showed that 44% of patients with chronic liver disease were at risk of developing hepatitis E. Hepatitis E vaccine, when available, is indicated for use in this group.
Superoxide and nitric oxide production by Kupffer cells in rats with obstructive jaundice: Effect of internal and external drainage
Authors: LI WEN , CHAN ANGUS CW , LAU JAMES YW , LEE DANNY WH , NG ENDERS KW , SUNG JOSEPH JY , CHUNG SC SYDNEY
Published: January 2004

Background and Aims:  The role of Kupffer cells in obstructive jaundice (OJ) has not been fully understood. The aims of the present study were to measure superoxide and nitric oxide (NO) production by Kupffer cells in experimental OJ in rats and to investigate the response to internal and external biliary drainage.

Methods:  Eighty male Sprague–Dawley rats were assigned to four groups: sham operation, OJ, and internal and external biliary drainage. Kupffer cells were isolated on day 7 in the sham operation and OJ group, and on day 7 after drainage procedures. Cells were cultured with or without lipopolysaccharide (LPS). Superoxide production was quantified in cultured Kupffer cells at 2 h and 48 h, respectively, after cell isolation using the superoxide dismutase inhibitable ferricytochrome c reduction method. Nitrite production in cell culture supernatants was measured 48 h later using Greiss reagents.

Results:  Without LPS stimulation, Kupffer cells produced comparable superoxide and nitrite in each group (P > 0.05). With LPS stimulation, Kupffer cells in the OJ group produced significantly higher superoxide anions than the other groups (P = 0.006). Nitrite production was significantly increased in the OJ group and external biliary drainage group compared to rats in the sham operation and internal drainage groups (P < 0.01).

Conclusions:  Kupffer cells from rats with OJ produce great amounts of endotoxin‐mediated oxidants. Both internal and external biliary drainage can decrease the elevated superoxide production. Internal drainage is superior to external drainage for reversing the distortional capacity of NO production by Kupffer cells.
Clinical usefulness of carbohydrate antigen 19‐9 as a screening test for pancreatic cancer in an asymptomatic population
Authors: KIM JEE‐EUN , LEE KYU TAEK , LEE JONG KYUN , PAIK SEUNG WOON , RHEE JONG CHUL , CHOI KYOO WAN
Published: January 2004

Background and Aim:  Although the prognosis for pancreatic cancer is generally poor, it is well known that the survival rate for resected pancreatic cancer is much higher than that for more conservative treatment. The importance of early detection is emphasized for resection of pancreatic cancer. Measurement of serum carbohydrate antigen (CA) 19‐9 has shown satisfactory sensitivity and predictive value in symptomatic patients, but no available data has been found on healthy asymptomatic subjects. Thus, the authors aimed to determine the clinical usefulness of CA 19‐9 as a screening tool for pancreatic cancer in asymptomatic subjects.

Methods:  From December 1994 to November 2000, 70 940 asymptomatic persons visiting the Health Promotion Center at the Samsung Medical Center, Seoul, Korea, participated. All subjects underwent abdominal ultrasonography and serum CA 19‐9 measurement. The authors analyzed the sensitivity, specificity, and predictive values of CA 19‐9 for detecting pancreatic cancer. Also, those subjects who had a serum CA 19‐9 level above the cut‐off value were followed up using a serial check of CA 19‐9, computed tomography, or endoscopic retrograde cholangiopancreatography.

Results:  The number of subjects with a level of CA 19‐9 above the cutoff of 37 U/mL was 1063 (1.5%), including four cases diagnosed with pancreatic cancer. The prevalence of pancreatic cancer over the age of 30 years is 13.66 per 100 000 population in Korea. Therefore, the sensitivity is 100% and the specificity 98.5%. However, the positive predictive value of CA 19‐9 for detecting pancreatic cancer is only 0.9% in the asymptomatic population.

Conclusion:  Mass screening for pancreatic cancer using CA 19‐9 levels in asymptomatic subjects is ineffective because of a very low positive predictive value, despite its high sensitivity and specificity.
Fifteen‐year follow up of endoscopic injection sclerotherapy in children with extrahepatic portal venous obstruction
Authors: ZARGAR SHOWKAT ALI , YATTOO GHULAM NABI , JAVID GUL , KHAN BASHIR AHMAD , SHAH ALTAF HUSSAIN , SHAH NISAR AHMAD , GULZAR GHULAM MOHAMMAD , SINGH JASWINDER , SHAFI HAKIM MOHAMAD
Published: January 2004

Background and Aim:  Endoscopic sclerotherapy has emerged as an effective treatment for bleeding esophageal varices both in adults and children but the long‐term outcome is poorly defined in children. The authors report a 15‐year follow up of sclerotherapy in children with extrahepatic portal venous obstruction.

Methods:  Between June 1982 and February 1992, 69 children with bleeding esophageal varices underwent sclerotherapy; variceal eradication was achieved in 63 (91.3%) patients, with procedure‐related morbidity of 28.9% and mortality of 1.4%. Fifty‐nine patients with variceal eradication were followed for between 10.4 and 20.1 years (mean, 15.1 ± 3.1 years).

Results:  After a median period of 3 years (range, 1.2–12.8 years), seven (11.9%) patients presented with recurrent bleeding (esophageal varices, four; gastric varices, two; and duodenal ulcer, one). Recurrent bleeding occurred in six of seven (85.7%) patients within the first 4 years of initial variceal eradication. Esophageal varices recurred in eight (13.6%) patients. Five of the seven patients with recurrent bleeding and all eight with recurrent varices were effectively treated with further sclerotherapy. Two patients with gastric variceal bleeding unresponsive to sclerotherapy underwent shunt surgery. Elective surgery was required in eight additional patients for reasons other than recurrent varices or bleeding.

Conclusions:  The authors conclude that (i) sclerotherapy is the ideal, safe and effective treatment for bleeding esophageal varices, that it prevented bleeding in 88.1% patients after variceal eradication and hence, should be included in primary management strategies; (ii) follow‐up endoscopy should be performed on a yearly basis for the first 4 years after variceal eradication; and (iii) surgery is required as a complementary technique for patients with uncontrolled bleeding, painful splenomegaly, growth retardation and symptomatic portal biliopathy.
Visceral perception thresholds after rectal thermal and pressure stimuli in irritable bowel syndrome patients
Authors: LI YANQING , WANG YANMEI , ZUO XIULI , GUO YUTING , ZHANG HAIYAN , LU XUEFENG , LI JUNMAN , DESMOND PAUL V
Published: January 2004

Background and Aim:  Visceral hypersensitivity has been shown to be present in irritable bowel syndrome (IBS). The current study sought to compare the characteristics of visceral perception thresholds after rectal thermal and pressure stimuli between IBS patients and healthy subjects.

Methods:  A total of 46 patients with IBS were diagnosed using Rome II criteria. Thirteen healthy individuals participated in the study. Rectal visceral perception thresholds were examined in patients with IBS and in normal controls after thermal and pressure stimuli. Subjects were asked to report the sensation type, location, and spread.

Results:  Compared with healthy subjects, IBS patients demonstrated significantly initially lower perception thresholds and defecation thresholds to rectal thermal and pressure stimuli, particularly in patients with diarrhea‐predominant IBS. Ice stimuli on the abdominal wall had varied effects on symptoms in patients with IBS and did not affect perception thresholds.

Conclusions:  Visceral perception thresholds were decreased significantly after rectal thermal and pressure stimuli in patients with IBS. Visceral hypersensitivity may be one of the important pathogenic mechanisms in IBS.
Cost of outpatient care in patients with inflammatory bowel disease in a German University Hospital
Authors: EBINGER MARGRIT , LEIDL REINER , Thomas Stefanie , Von Tirpitz Christian , REINSHAGEN MAX , ADLER GUIDO , KÖNIG HANS‐HELMUT
Published: January 2004

Background and Aim:  Because of its long duration, inflammatory bowel disease (IBD) causes high use of health services and high lifetime costs for medical care. The aim of the present study was to measure the costs of outpatient care in patients with IBD in a German University Hospital and to identify potentially relevant determinants of costs.

Methods:  The use of resources of 599 outpatient patients treated at a German University Hospital (65% Crohn's disease [CD] and 26% ulcerative colitis [UC]) was measured using a routine database. Costs of medical services (diagnostics and treatment) were considered as well as costs of medication. Resource use was valued using fee schedules for hospital services and pharmacy prices for drugs.

Results:  The mean cost of one outpatient visit was €162, including physician costs, laboratory costs, and costs of diagnostic procedures following the visit. For a subgroup of 272 patients, the mean annual cost for outpatient care was €3171. Medication accounted for 85% of the total annual costs. Potential determinants, such as main diagnosis (CD or UC), sex, age, localization of disease, and occurrence of anemia, had no influence on costs, whereas complications of IBD and use of corticosteroids showed an impact on annual costs.

Conclusions:  This is the first time that the structure and range of outpatient treatment costs for IBD have been demonstrated for a German hospital.
Etiology and outcome of fulminant hepatic failure managed at an Australian liver transplant unit
Authors: GOW PAUL J , JONES ROBERT M , DOBSON JACQUI L , ANGUS PETER W
Published: January 2004

Background and Aims:  The primary aims were to identify the incidence, etiology and outcome of all adult cases of fulminant hepatic failure (FHF) presenting to the Victorian Liver Transplant Unit over the 14 year period since the Unit was established in 1988.

Methods:  The database of the Unit was used to identify all adult patients (>16 years) who were referred to the Austin and Repatriation Medical Center in Melbourne with FHF between 1988 and 2001. The Austin and Repatriation Medical Center is the sole provider of adult liver transplantation services for the states of Victoria and Tasmania.

Results:  80 patients (64 female, 14 male) with FHF were referred, at a rate of approximately one case per million population per year. The mean age was 37.6 ± 13.7 years. Most cases were due to either paracetamol poisoning n = 29 (36%) or non‐A non‐B (idiopathic) hepatitis n = 27 (34%). Thirty‐five patients were listed for transplantation, of which 26 underwent the procedure (77% of transplantation patients currently alive). Nine patients were listed for transplantation but did not undergo the procedure, eight died before a donor became available and one recovered. Of the 30 patients who survived without transplantation, 20 cases were due to paracetamol poisoning.

Conclusions:  Liver transplantation has had a major impact on survival of patients with FHF, most significantly in patients with FHF due to causes other than paracetamol poisoning, in whom survival without transplantation is uncommon. Survival in those who undergo transplantation for FHF is excellent, but a significant percentage of patients listed for transplantation die before a donor organ becomes available.
Electric activity of the colon in irritable bowel syndrome: The ‘tachyarrhythmic’ electric pattern
Authors: SHAFIK AHMED , EL‐SIBAI OLFAT , SHAFIK ALI A , AHMED ISMAIL
Published: January 2004

Background and Aim:  The etiology of irritable bowel syndrome is unknown. It presents with crampy abdominal pain associated with alternating constipation and diarrhea but with no anatomic abnormality on diagnostic testing. Because the condition is related to motility disturbance, the hypothesis that a disorder of the colonic electromyographic activity is responsible for the colonic motile disorders in irritable bowel syndrome, was investigated.

Methods:  The electromyographic activity of the sigmoid colon was recorded transcutaneously in 18 patients with irritable bowel syndrome (49.6 ± 10.2 years, 12 women) and 14 healthy volunteers (47.2 ± 9.9 years; eight women) by applying three electrodes to the abdominal skin below the umbilicus. The sigmoid colon pressure was measured by means of a saline‐perfused tube connected to a pneumohydraulic capillary infusion system.

Results:  Slow waves with a regular rhythm were recorded in the healthy volunteers exhibiting the same frequency, amplitude and conduction velocity from all three electrodes. Action potentials (AP) were not registered. The basal sigmoid colon pressure was interrupted by bouts of elevation. In irritable bowel syndrome, the electromyographic rhythm was irregular and the slow wave variables were higher than those of the normal volunteers and were not the same from the three electrodes; occasional AP were also recorded. The sigmoid colon basal pressure was significantly higher, and was interrupted by pressure bouts significantly higher, than those of the volunteers.

Conclusions:  Irritable bowel syndrome exhibited a ‘tachyarrhythmic’ pattern of electromyographic activity with higher slow wave variables than normal and occasional AP. The resulting elevated basal colonic pressure and tone may explain some of the irritable bowel syndrome symptoms. Because diagnostic testing of the irritable bowel syndrome shows no anatomic abnormalities, it is suggested that the cause of irritable bowel syndrome is related to an abnormal focus in one or more of the colonic pacemakers emitting these abnormal waves. However, further studies are required to verify these findings.
Novel human, mouse and xenopus genes encoding a member of the RAS superfamily of low‐molecular‐weight GTP‐binding proteins and its downregulation in W/WV mouse jejunum
Authors: DAIGO YATARO , TAKAYAMA ICHIRO , PONDER BRUCE AJ , CALDAS CARLOS , WARD SEAN M , SANDERS KENTON M , FUJINO MASAYUKI A
Published: January 2004

Background and Aim:  Interstitial cells of Cajal (ICC) are pacemakers and mediators of neurotransmission in gastroenteric smooth muscles. Interstitial cells of Cajal require cellular signaling via KIT, a receptor tyrosine kinase, for development and maintenance of cellular phenotype. Much of the evidence demonstrating the functions of ICC comes from studies of W/W V mutant mice, which have reduced KIT function. The aim of the present study was to differentially examine gene expression in the small intestines of wild‐type and W/W V mice.

Methods:  RNA from the jejunum of wild‐type and W/W V mice was analyzed using a differential gene display method.

Results:  One candidate gene, encoding a novel small GTPase of the RAS superfamily, was significantly suppressed both in fed and starved W/WV mice. The full‐length clone of the murine gene and its human and xenopus counterparts were designated GTP‐binding protein, 28 kDa (G28K). Human G28K cDNA encodes a protein of 258 amino acids with homology to the human cell division cycle 42/G25K protein. This gene is located at 1q42.11–q42.3. G28K was abundantly expressed in the human stomach and the small intestine. Semi‐quantitative reverse transcription–polymerase chain reaction analysis revealed expression of G28K mRNA within single isolated ICC.

Conclusions:  Gene analysis showed that G28K was differentially expressed in the small intestines of wild‐type and W/W V mice. Interstitial cells of Cajal within the small intestine expressed mRNA for G28K. The specific downregulation of G28K in the jejunum of W/W V mice, and high expression in human intestinal tissue suggest that the G28K gene might be associated with ICC function in mice and in humans.