bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spontaneous bacterial peritonitis associated with experimental cirrhosis: Comparative effect of different therapeutic options on endotoxinemia and hemodynamic derangement
Authors: MAROTTA F , NAITO Y , HELMY A , OLIVA E , MINELLI E , YOSHIOKA M , MIN CH 
Published: July 2003

OBJECTIVE:  The aim of this investigation was to assess the role of different therapeutic options aimed at modifying the gut microecology in experimental liver cirrhosis in view of the cytokine cascade and splanchnic and systemic hemodynamics.METHODS:  Cirrhosis was induced in male Sprague‐Dawley rats by carbon tetrachloride (CCL4). After the 6th week of CCL4 administration rats were divided into 5 groups for the remaining 6 weeks: (A) saline b.i.d; (B) lactulose 0.5 g b.i.d.; (C) rifaximine 1 mg b.i.d; (D) 2 mL b.i.d of a probiotic mixture and (E) 1 week of rifaximine followed by 5 weeks of probiotic.RESULTS:  Rats with cirrhosis and ascites showed a significantly high concentration of either portal, splanchnic and systemic endotoxin, as well as plasma TNF‐α concentration (P < 0.05). Rifaximine alone, rifaximine plus probiotic or probiotic alone significantly decreased the plasma endotoxin concentration at each of the three tested sites, as well as the plasma concentration of TNF‐α (P < 0.01). Total Gram‐negative aerobic bacteria count in the stool markedly decreased together with a significant increase of the enterococcal population in the rifaximine plus probiotic group and, to a lesser extent, in the other treatment groups. Treated rats showed a significantly decreased occurrence of bacterial peritonitis and the rifaximine plus probiotic treatment was the most effective regimen. Each of the treatments significantly reduced the percentage of positive culture of either mesenteric lymph node or portal vein samples, rifaximine plus probiotic being the most effective. As compared with healthy control rats, those with cirrhosis showed a significantly lower mean arterial pressure and systemic vascular resistance, but a higher cardiac index and portal pressure. Spontaneous bacterial peritonitis further worsened the systemic vascular resistance, but this was partly improved by the rifaximine plus probiotic treatment.CONCLUSION:  These data suggest that the association of a nonabsorbable antibiotic with a probiotic beneficially affects the abnormal systemic vasodilatory response in the course of severe liver cirrhosis, probably through the effects on endotoxin and indirect inhibition of TNF−α release.
Angiotensin II stimulates the synthesis of nucleic acid, protein and collagen of cultured hepatic stellate cells in rats
Authors: WANG Yu Qing , LI Ding Guo , WEI Hong Shan , WANG Zhi Rong , HUANG Xin , ZHOU Xin , XU Qin Fang , LU Han Ming 
Published: July 2003

OBJECTIVE:  To investigate the effects of different doses of angiotensin II (AngII) on the proliferation of hepatic stellate cells (HSC) and collagen synthesis in rats.METHODS:  Pronase E and collagen I were used to isolate the HSC, and 3H‐TdR,3H‐Leu and 3H‐pro incorporation methods were used to evaluate the effects of the different doses of AngII on HSC DNA, protein and proline synthesis.RESULTS:  It was found that 10‐9−10−6 mol/L AngII could increase the 3H‐TdR incorporation rate of the HSC (P < 0.05), but only 10−6 mol/L and 10−7 mol/L AngII could significantly increase the 3H‐Leu incorporation rate of the HSC (P < 0.01); 10−9−10−6 mol/L AngII caused a significant increment of the 3H‐pro incorporation rate of the HSC in a dose‐dependent manner.CONCLUSIONS:  The appropriate dose of AngII may promote HSC proliferation and collagen synthesis.
Differentiation of mouse embryonic stem cells into hepatocytes in vitro and in vivo
Authors: KUAI Xiao Ling , BIAN Yu Hai , CONG Xiao Qian , LI Xiu Lan , XIAO Shu Dong 
Published: July 2003

OBJECTIVE:  Embryonic stem (ES) cells have a pluripotent ability to differentiate into a variety of cell lineages. Cell‐to‐cell contact is important for cell differentiation. Mouse ES cells were cocultured with mouse fetal liver cells and the green fluorescent protein (GFP) positive ES cells were transplanted into rats liver through the portal vein in order to investigate their potential to differentiate into hepatocytes.METHODS:  Mouse ES cells were cocultured with the mouse fetal liver cell line, BNL.CL2. They did not make direct contact; instead the culture media was exchanged freely. After coculture for 48 h, albumin, transthyretin, glucose 6 phosphates, hepatic nuclear factor 4 and SEK1 mRNA were assayed by RT‐PCR, and alpha‐fetoprotein by immunohistochemistry. The morphology was investigated by microscopy. After transplantion of the GFP‐positive ES cells, the whole liver was removed from a rat every four days. The liver slices were examined under a fluorescent microscope to detect the GFP‐positive cells. Albumin was detected on the same slices by immunohistochemistry.RESULTS:  After coculture with BNL.CL2 cells, the differentiated ES cells had the same morphology as the BNL.CL2 cells, and albumin, transthyretin, glucose 6 phosphates and SEK‐1 mRNA were found by RT‐PCR, and alpha‐fetoprotein was detected immuno­histochemically. The transplanted GFP‐positive ES cells were found in the rats’ liver slices by GFP fluorescence, and development of teratomas was not observed. The immunohistochemistry results indicated that the transplanted GFP‐positive ES cells retained an albumin‐producing ability.CONCLUSIONS:  Cell‐to‐cell contact is important for the differentiation of ES cells. Mouse embryonic stem cells can differentiate into hepatocytes directly either in vitro or in vivo.
Extracellular calcium level is crucial for aortic contractile response in pregnant rat
Authors: Dièye Amadou Moctar , Gairard Alexis 
Published: July 2003

AbstractStudies of vascular reactivity during late pregnancy were performed to investigate the previously described hyporeactivity to vasopressors. Two groups of seven control (nonpregnant) and seven late pregnant (day 20) Wistar rats were used. Rubbed (E‐) segments from thoracic aorta were studied for contractile studies in a Krebs solution containing either 1.25 or 2.50 mmol/L Ca concentration. Norepinephrine (NE; 10−9–3 × 10−5) or depolarization induced (KCl, 100 mmol/L) contractions are given as mN/mm2.With 2.50 mmol/L Ca, the maximal contraction to NE in E‐segments is decreased in late pregnant rats compared with nonpregnant rats. However, this difference disappears when calcium concentration is set to 1.25 mmol/L Ca, the physiological value for free calcium concentration in extracellular fluid. For the contraction induced by opening of voltage operated calcium channels (KCl depolarization), a decreased maximal tension is also obtained in the pregnant rats compared with nonpregnant only with 2.50 mmol/L Ca concentration.It appears that aortic response to vasoconstrictors is modulated by extracellular calcium concentration in a different way between pregnant and nonpregnant rats.
Effect of two new PBN‐derived phosphorylated nitrones against postischaemic ventricular dysrhythmias
Authors: Vergely Catherine , Renard Céline , Moreau Daniel , Perrin‐ Sarrado Caroline , Roubaud Valérie , Tuccio Béatrice , Rochette Luc 
Published: July 2003

AbstractSpin traps might exert antioxidant cardioprotective effects during myocardial ischaemia–reperfusion where free radicals are thought to be responsible for the occurrence of reperfusion injury. The aim of our study was to investigate the effects of two new α‐phenyl N‐tert‐butylnitrone (PBN)‐derived β‐phosphorylated nitrones: 2‐N‐oxy‐N‐[benzylidène amino] diéthyl propyl‐2‐phosphate (PPN) and 1‐diethoxyphosphoryl‐1‐methyl‐N‐[(1‐oxido‐pyridin‐1‐ium‐4‐yl) methylidene] ethylamine N‐oxide (4‐PyOPN) compared with PBN on (1) the evolution of cardiovascular parameters and (2) the postischaemic recovery. Anaesthetized rats were injected with 120 μmol/kg of the nitrones or 14 μmol/kg of amiodarone, used as a reference antidysrhythmic drug. Ischaemia was induced in vivo through ligation of the left anterior descending coronary artery for 5 min followed by 15 min of reperfusion after release. Cardiovascular parameters and occurrence of ventricular premature beats (VPB), ventricular tachycardia (VT) and fibrillation (VF) were recorded throughout the experiment. Under nonischaemic conditions, none of the three spin traps was shown to modify cardiovascular parameters during the 25‐min measurement period. Solvent‐treated (NaCl 0.9%) animals challenged with ischaemia–reperfusion exhibited 39 ± 10 VPB, 156 ± 39 s of VT and 60% mortality caused by sustained VF. Nitrones improved slightly postischaemic recovery, reducing the occurrence of VF and mortality to 33% whereas amiodarone injection totally suppressed rhythm disturbances and mortality. Our study has shown only limited antidysrhythmic cardioprotective effects of PBN‐derived β‐phosphorylated nitrones during reperfusion after a regional myocardial ischaemia but also minor antioxidant properties of these spin trapping agents.
Variation in the use of pasture by breeding European Golden Plovers Pluvialis apricaria in relation to prey availability
Authors: Pearce‐Higgins J. W. , Yalden D. W. 
Published: July 2003

European Golden Plover Pluvialis apricaria populations have declined across Western Europe. Changes to upland grasslands that are utilized by foraging off‐duty birds may have contributed to this decline. The use of enclosed agricultural land by a stable breeding population of Golden Plovers in the South Pennines is described to examine this hypothesis. Fields contained foraging plovers from the end of February to the end of July. Off‐duty incubating birds commuted to feed on fields, females during the day and males at night. During the day, adults flew from 6.6 to 7.2 km from the nest to feed, whilst at night birds commuted from 2.4 to 2.7 km. The length of time spent foraging by males was inversely dependent upon daylength. Following hatching, the use of pasture declined, although not as much as in other studies. Arable and improved fields received most use by 15 radiotagged birds, whilst the use of pasture throughout the breeding season was negatively correlated with sward height. Adult diet consisted largely of subsurface prey, particularly larval tipulids, although earthworms were an important component in March and April. The biomass of larval tipulids was strongly correlated with an index of the use of fields. The selection of fields by Golden Plovers is therefore dependent upon prey abundance and availability, and, consequently, is likely to be enhanced by summer grazing and poor drainage. These findings are discussed in the light of recent trends in pastoral management.
Dispersal and migration of juvenile African Black OystercatchersHaematopus moquini
Authors: Hockey Philip A. R. , Leseberg Antje , Loewenthal Douglas 
Published: July 2003

African Black OystercatchersHaematopus moquiniare sedentary as adults. However, colour‐ringing of more than 700 juveniles has revealed complex post‐fledging movements that vary geographically. Young from the western part of the breeding range either remain within 150 km of their natal site or migrate 1500–2000 km to one of five discrete nursery areas on the Namib Desert coast of central and northern Namibia, and southern Angola. These nurseries all lie north of the species’ breeding range. We calculate that 36–46% of all juveniles born in South Africa migrate to nurseries. Birds return to their natal sites from nurseries at 2–3 years old, but never migrate again. Juveniles from the eastern part of the range undertake ‘diffusion dispersal’, regularly up to 1000 km, but these journeys mostly end within the breeding range, where there are no nurseries. Very few eastern birds reach nurseries. There is no evidence that movements of western birds are density‐dependent responses to hatching date, but long‐distance migrants are significantly heavier as chicks than are short‐distance dispersers. We hypothesize that a genetic basis exists to these movements, possibly triggered by body condition, that could account not only for the highly dichotomous behaviour of western birds, but also for the intermediate behaviour of eastern birds.
The status and recent breeding performance of the critically endangered Northern Bald Ibis Geronticus eremita population on the Atlantic coast of Morocco
Authors: Bowden Christopher G. R. , Aghnaj Ali , Smith Ken W. , Ribi Mohamed 
Published: July 2003

The main wild population of the Northern Bald Ibis Geronticus eremita breeds on the Atlantic coast of Morocco in the Agadir region. This paper describes the numbers of breeding pairs over the last two decades, the recent breeding performance, the causes of egg and chick losses and their conservation implications. Since 1980 there has been no overall decline in numbers with, over the last 5 years, 59–74 pairs breeding and a peak prebreeding population of around 220 birds. In contrast with the now extinct Northern Bald Ibis populations in Turkey and elsewhere in Morocco, the birds are present in the Agadir region throughout the year and do not appear to migrate from the area outside the breeding season. Breeding performance is highly variable from one year to the next but does not appear to be related to rainfall in the vicinity of the colonies as has been reported elsewhere. It is suggested that coastal fogs in this region may buffer the adverse impacts of low rainfall and may in part account for the year‐round residency of the birds. The main causes of breeding failures have been loss of eggs to predators and, most importantly, poor chick survival as a result of starvation and predation. Conservation action to date has focused on reducing the negative influences on breeding success but it is recognized that for such a long‐lived bird adult survival is also likely to be an important limiting factor on the population size.
Genetic and morphological differentiation between the two largest breeding colonies of Audouin's Gull Larus audouinii
Authors: Genovart Meritxell , Oro Daniel , Bonhomme François 
Published: July 2003

We assessed the genetic and morphological differences between the two largest breeding colonies of Audouin's Gull Larus audouinii, an endemic seabird species of the Mediterranean region. The two colonies comprise c. 75% of the total world population and are 655 km apart. The Ebro Delta colony was formed recently and, after dramatic growth mainly due to high rates of both immigration and reproductive success, is now the largest in the world (more than 60% of the total population). The Chafarinas Islands support an ancient colony with relatively little fluctuation in breeding numbers. The two colonies also differ greatly in environmental conditions, with the Ebro Delta being a higher quality breeding site. Very little movement occurs between the two colonies. We collected morphological data and blood samples from both colonies. Polymorphic microsatellite markers were used to study the genetic differentiation. These showed no significant variation between colonies, nor evidence of a founder effect in the Ebro Delta. Individuals from the Ebro Delta were larger than those from Chafarinas, the difference being greater for males. This probably reflects a stronger male susceptibility to worse environmental conditions during chick growth at the Chafarinas Islands.
Rapid evolution of a novel song and an increase in repertoire size in an island population of an Australian songbird
Authors: Baker Myron C. , Baker Merrill S. A. , Baker Esther M. 
Published: July 2003

Cultural innovations are commonly noted in animals, but times of development of novel traits are usually unknown. We report here a novel song type arising in a bird population on an offshore island of Western Australia where the time of colonization of the island by the Western Gerygone Gerygone fusca is known. On the mainland, a single song type is widespread. On Rottnest Island, many individuals sing a different type of song and a number possess a repertoire of two song types: the standard song shared with the mainland and the novel song type not found on the neighbouring mainland. The novel song type found on Rottnest is so different in its syntactical structure that one could easily mistake it for that of a new species. The characteristic song of mainland birds is irregular in the frequencies at which the notes within a song are delivered. The novel song on Rottnest has a highly structured syntax with notes delivered at a strict and repeated sequence of frequencies resulting in a rhythmic musical sound. The species is known to have colonized Rottnest in about 1955. The new song type apparently developed rapidly by cultural evolution in the last 50 years.
The decline of Common KestrelsFalco tinnunculusin a forested area of northern England: the role of predation by Northern GoshawksAccipiter gentilis
Authors: Petty S. J. , Anderson D. I. K. , Davison M. , Little B. , Sherratt T. N. , Thomas C. J. , Lambin X. 
Published: July 2003

We have previously documented the decline of the Common KestrelFalco tinnunculusover a 23‐year period in a large coniferous forest in northern England. Kestrels fed predominantly on Field VolesMicrotus agrestis, which were most abundant in young plantations (1–11 years old). Over the 23 years, voles remained abundant in the study area, but their numbers fluctuated cyclically. Here we consider whether the decline of Kestrels was linked to predation by Northern GoshawkAccipiter gentilis. Goshawks first bred in the study area in 1973 and increased until 1989, after which numbers stabilized. We use a number of approaches to explore the role of Goshawk predation, all of which are correlative, but independent. First, there was a significant negative relationship between Kestrel and Goshawk numbers after controlling for a decline in vole habitat. Short‐eared OwlsAsio flammeus, which also hunt by day, declined over the same period as Kestrels. Second, numbers of Tawny OwlStrix alucoand Long‐eared OwlAsio otusdid not decline as Goshawk numbers increased. These two species are also vole‐dependent, but active by night, and less vulnerable to Goshawk attack. Third, six species of raptor comprised 4.5% of 5445 Goshawk prey items during the breeding season, but more Kestrels were killed than the combined total of all other raptors. Goshawks not only killed many adult Kestrels in early spring, prior to breeding, when it would have most impact on population levels, but there was also a temporal trend for predation on Kestrels to be inversely density‐dependent. Finally, we estimated that Goshawks removed more Kestrels than were recorded each spring in the study area. We interpreted this as indicating that immigrant Kestrels were being removed continually, mostly before they could breed. We conclude that the decline of Kestrels (and possibly Short‐eared Owls) was mainly due to predation by Goshawks. This study provides some of the strongest evidence yet of the role of predation in the hierarchical structuring of raptor communities.
The disproportionate effect of global warming on the arrival dates of short‐distance migratory birds in North America
Authors: Butler Christopher J. 
Published: July 2003

Recent studies have shown that, in response to global climate change, diverse avian taxa are now nesting measurably earlier (< 10 days) in both the United States and Britain. Similarly, several studies on European birds have now demonstrated that a variety of species (although not all) are arriving increasingly early. However, surprisingly, widespread changes in North American migrant phenology have not been demonstrated. It is hypothesized that short‐distance migrants (birds that winter in the southern United States) may be quicker to adapt to climate change than long‐distance migrants (birds that winter south of the United States), as short‐distance migrants can respond to meteorological cues indicating weather conditions to the north whereas long‐distance migrants must rely on photoperiod. This study examined the first arrival dates of 103 migrant birds in New York and Massachusetts and found that, on average, all migrants arrived significantly earlier during the period 1951–1993 than the period 1903–1950. From 1951–1993 birds wintering in the southern United States arrived on average 13 days earlier while birds wintering in South America arrived 4 days earlier. Although a change in observer effort cannot be quantified and may be a source of bias, a comparison of the numbers of reporting observers during the 1930s and the 1980s revealed no significant difference. These results are consistent with those expected under a scenario of global warming.
Dispersal and migration of juvenile African Black Oystercatchers Haematopus moquini
Authors: Hockey Philip A. R. , Leseberg Antje , Loewenthal Douglas 
Published: July 2003

African Black Oystercatchers Haematopus moquini are sedentary as adults. However, colour‐ringing of more than 700 juveniles has revealed complex post‐fledging movements that vary geographically. Young from the western part of the breeding range either remain within 150 km of their natal site or migrate 1500–2000 km to one of five discrete nursery areas on the Namib Desert coast of central and northern Namibia, and southern Angola. These nurseries all lie north of the species’ breeding range. We calculate that 36–46% of all juveniles born in South Africa migrate to nurseries. Birds return to their natal sites from nurseries at 2–3 years old, but never migrate again. Juveniles from the eastern part of the range undertake ‘diffusion dispersal’, regularly up to 1000 km, but these journeys mostly end within the breeding range, where there are no nurseries. Very few eastern birds reach nurseries. There is no evidence that movements of western birds are density‐dependent responses to hatching date, but long‐distance migrants are significantly heavier as chicks than are short‐distance dispersers. We hypothesize that a genetic basis exists to these movements, possibly triggered by body condition, that could account not only for the highly dichotomous behaviour of western birds, but also for the intermediate behaviour of eastern birds.
Measuring sexual size dimorphism in birds
Authors: Greenwood Julian G. 
Published: July 2003

Numerous studies have examined sexual size dimorphism in birds and speculated upon the reasons for its existence. Whilst most studies have focused on individual species or groups of related species, a few have attempted to disentangle the various hypotheses that have been put forward to explain its occurrence. Typical of the latter studies is that by Jehl and Murray (1986), in which they argued that sexual size dimorphism was primarily the result of sexual selection (see also Bennett & Owens 2002). Although some studies have looked at patterns in sexual size dimorphism without calculating a figure to represent the difference (e.g. Amadon 1959), most have examined measurements of birds and used these to calculate such a figure. Traditionally in such studies, measurements used have included wing‐length, culmen‐length, tarsus‐length and mass, although McGillivray (1989) took the sum of 18 skeletal measurements and used their male and female means to determine sexual size dimorphism. Wing‐length has commonly been used to determine sexual size dimorphism, although lack of repeatability of measurements may render it less useful than skeletal measurements like tarsus‐length as in studies of Dunlin Calidris alpina (Blomqvist et al. 1997) and Savannah Sparrows Passerculus sandwichensis (Rising & Somers 1989); however, Gosler et al. (1998) found wing‐length measurements to be more repeatable than other metrics in a group of 27 passerines.