bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental study of the safety of the selective COX‐2 inhibitor, celecoxib, for gastric mucosa
Authors: LI Jun Ting , LI Zhao Shen , ZHAN Xian Bao , CUI Zhong Min , NIE Shi Nan
Published: July 2003

OBJECTIVE:  To compare the gastric mucosal damage induced by a COX‐2 inhibitor, celecoxib, and a conventional NSAID, indomethacin.

METHODS:  A rat model of NSAID‐induced gastric mucosal damage was prepared for indomethacin and celecoxib separately (n = 8). After gastric damage was induced by 100% ethanol, celecoxib was administered by gastric gavage (n = 8). Gastric mucosal concentrations of 6‐keto‐PGF1α and TXB2 and the lesion index (LI) were measured. Morphological changes of the gastric mucosa were assessed under light and scanning electron microscopy.

RESULTS:  Indomethacin caused marked gastric damage (LI: 13.38 ± 2.06) and significant reduction of the concentrations of 6‐keto‐PGF1α and TXB2 (P < 0.01), Celecoxib did not produce necrotic injuries on healthy gastric mucosa (LI: 0), but the mucosal injuries previously induced by ethanol worsened after its administration (LI: 37.19 ± 3.34 vs 19.90 ± 2.28, P < 0.01).

CONCLUSIONS:  Inhibition of COX‐1 is the major mechanism of NSAIDs in producing gastric mucosal damage. As a selective COX‐2 inhibitor, celecoxib does not produce toxic injuries of the healthy gastric mucosa, and is thus safer than conventional NSAID. However, when administered in the presence of an altered gastric mucosa, gastric injuries were worsened.
Effect of SU5416 on the inhibition of growth and metastasis of human gastric cancer implanted in nude mice
Authors: ZHANG Guo Feng , WANG Yuan He , WANG Qiang , ZHANG Min Gao , HAN Ce Ran , Yang RAO Ying
Published: July 2003

OBJECTIVE:  To study the effects of the angio­genesis inhibitor SU5416 on the growth and liver metastasis of gastric cancer and to investigate its effects on the apoptosis of gastric cancer cells.

METHODS:  A model simulating the metastasis of human gastric cancer was established by orthotopic implantation of histologically intact human tumor tissue into the gastric wall of nude mice, which were randomly divided into four groups: control group (saline solution), 5‐FU group (fluorouracil 30 mg/kg per day i.p), SU5416 group (SU5416 15 mg/kg per day i.p.), and combined treatment with 5‐Fu and SU5416. Eight weeks after implantation, the tumor weight, inhibition rate, intratumoral microvessel density (MVD), apoptotic index (AI), and the status of metastasis were evaluated after the mice were killed.

RESULTS:  Compared with the control group, the growth of the orthotopically‐implanted tumors was significantly inhibited, with reduced weight, and the tumor inhibition rate was 44.5%, 79.3%, and 84.4%, respectively, in the mice treated with 5‐FU, SU5416 and both. The incidence of liver metastasis was also significantly decreased in the 5‐Fu, SU5416, and combination groups compared with the control group (36.4%, 25.0%, and 0% vs 90.0%). The MVD of the 5‐FU group, the SU5416 group and the combined group was 13.1 ± 4.7, 3.9 ± 1.8 and 2.1 ± 1.5, respectively, which was decreased significantly compared with the control group (14.6 ± 5.8). The AI was increased significantly in the treated mice (6.81 ± 4.92%, 9.82 ± 3.76% and 17.65 ± 9.85% vs 3.76 ± 2.25%). The growth of and liver metastasis of the human gastric cancer implanted in the nude mice were both more significantly inhibited in the SU5416 group and the combined group than in the control and 5‐FU groups (P < 0.05).

CONCLUSIONS:  SU5416 can induce apoptosis in gastric cancer by inhibiting tumor angiogenesis and has a strong inhibitory effect on both the growth and liver metastasis of gastric cancer implanted in nude mice. The combination of SU5416 with other cytotoxic agents is more effective.
Clinical and endoscopic features of ischemic colitis
Authors: YANG Xue Song , LU Yu Min , YU Chang Fu , WANG Chang Wu
Published: July 2003

OBJECTIVE:  To review the clinical and endoscopic features, and outcome of ischemic colitis.

METHODS:  Sixty cases with the diagnosis of ischemic colitis were retrospectively analyzed. All the patients were under observation in hospital and most of them underwent colonoscopy at least twice: once for diagnosis and then follow‐up after treatment. The demographic data, presenting symptoms, endoscopic findings, laboratory tests, and treatment were reviewed.

RESULTS:  Fifty‐two of the 60 cases were over 50 years old (87%; mean age, 59.9 years): 40 female, 20 male (2 : 1); 76.0% of these patients had a coexistent disease such as a cardio‐cerebrovascular disorder, diabetes, hematologic diseases or a previous history of abdominal surgery. Abdominal pain (57/60, 95%), hematochezia (55/60, 91.7%), and diarrhea (26/60, 43.3%) were the main complaints. Lesions seen on colonoscopy were more commonly located in the left colon (46/60, 79.3%) and rectum (5/60, 8.6%), and were characteristically segment‐distributed, including hemorrhagic edematous mucosa, erosions, ulcerations, pseudopolyps, and stricture. Ultrasonography revealed colonic wall thickening in 13 cases (13/55, 21.7%), and small to moderate ascites was detected in 4 cases (4/55, 7.3%). In this cohort, most of the patients recovered (49/60, 81.7%) or improved (10/60, 16.7%) after conservative treatment. Only one patient who had a myocardial infarction prior to the onset of the ischemic colitis, died from peritonitis complicated with septic shock. Progress and outcome were associated with the patient's age, severity of the lesions, clinical course, underlying diseases and the complications.

CONCLUSION:  Colonoscopy is safe and helpful in the early diagnosis of ischemic colitis. Nongangrenous colonic ischemia usually requires only medical management and is associated with a good prognosis.
Clinical application of wireless capsule endoscopy
Authors: GE Zhi Zheng , HU Yun Biao , GAO Yun Jie , XIAO Shu Dong
Published: July 2003

BACKGROUND:  Diagnostic modalities for identifying lesions within the small bowel have been quite limited. Wireless capsule endoscopy (WCE) is a new, innovative technique that can detect very small mucosal lesions in the entire small bowel and can be used in the outpatient setting. The present study explored the diagnostic value, tolerance and safety of WCE in the identification of small bowel pathology that was not detected with conventional small bowel imaging studies.

METHODS:  From May through September 2002, 15 patients with suspected small bowel diseases were prospectively examined, Of them, 12 presented with persistent obscure gastrointestinal bleeding and negative findings on upper endoscopy, colonoscopy, small bowel radiography, and bleeding‐scan scintig‐raphy or mesenteric angiography.

RESULTS:  Wireless capsule endoscopy identified pathologic small bowel findings in 11 of the 15 patients (73%): angioectasias, Dieulafoy's lesion, polypoid lesion, submucosal mass, Crohn's disease, carcinoid tumor, lipoma, aphthous ulcer, and hemorrhagic gastritis; four of the patients had two lesions. The images displayed were considered to be good. The capsule endoscopes remained in the stomach for an average of 82 min (range 6−311 min) and the mean transit time in the small bowel was 248 min (range 104−396 min). The mean time of recording was 7 h 29 min (from 5 h to 8 h 30 min). The mean time to reach the cecum was 336 min (180−470 min). The average number of the images transmitted by the capsule was 57 919 and the average time the physician took to review the images transmitted by the capsule was 82 min (range 30−120 min). The average time of elimination of the capsule was 33 h (range 24−48 h). All 15 patients reported that the capsule was easy to swallow, painless, and preferable to conventional endoscopy. No complications were observed.

CONCLUSIONS:  Wireless capsule endoscopy is safe, well tolerated, and useful for identifying occult lesions of the small bowel, especially in patients who present with obscure gastrointestinal bleeding.
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

Studies 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

Spin 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.
A new Eocene swift‐like bird with a peculiar feathering
Authors: Mayr Gerald
Published: July 2003

A new taxon of swift‐like birds is described from the Middle Eocene of Messel (Germany). It is tentatively assigned to the extinct family Jungornithidae and exhibits a completely unexpected feathering, which contrasts sharply with that of recent swifts. The short and rounded wings clearly show that it was not adapted to gliding, but might have caught its prey by sallying flights from a perch. The tail of the new taxon is very long and the tail feathers are broad and nearly symmetrical. The phylogenetic relationships between the Jungornithidae and other apodiform birds are still not convincingly resolved. The early Oligocene genus Jungornis itself shares unique derived characters with hummingbirds which are, however, absent in the Eocene genus Argornis and in the new taxon from Messel.
Nest‐site characteristics of the Red‐knobbed Hornbill Aceros cassidix and Sulawesi Dwarf Hornbill Penelopides exarhatus
Authors: Cahill Alexis J.
Published: July 2003

Nest‐site characteristics of two hornbill species, the Red‐knobbed Hornbill Aceros cassidix and the Sulawesi Dwarf Hornbill Penelopides exarhatus, are presented and compared at two sites in north Sulawesi, Indonesia. Seventy‐four Red‐knobbed Hornbill and 12 Sulawesi Dwarf Hornbill nests were located. Sulawesi Dwarf Hornbill nests were at lower densities and more evenly spaced than Red‐knobbed Hornbill nests. Although selective, neither species appeared to be nest‐site limited, except perhaps for the Red‐knobbed Hornbill in hill forest. Principal components analysis indicated that Red‐knobbed Hornbills were ‘catholic’ in their preferences, although nests were generally in tall, mature specimens of large girth, located high and in the upper half of the tree. The Sulawesi Dwarf Hornbill nested exclusively in live trees and nests were on average located half way up in tall canopy trees with large girths. Within certain parameters, both species were flexible with respect to their nest cavity size and shape requirements; Red‐knobbed Hornbills choose sites with larger entrances and internal dimensions. Discriminant function analysis produced parsimonious models for each site, with high rates of correct classification, based on structural, floristic and breeding success parameters. Lack of transference of predictive powers of the models between sites demonstrates the apparent variability in hornbill nesting behaviour and indicates the need for caution when extrapolating models to other sites. Possible factors affecting the nesting density and distribution of each hornbill species are discussed.
Breeding density affects the honesty of bird vocal displays as possible indicators of male/territory quality
Authors: Penteriani Vincenzo
Published: July 2003

Vocal displays are supposed to be an honest signal of the phenotypic and genetic quality of individuals and their territory. Moreover, signal interactions are nearly always associated with individuals in aggregations, and their function could in part be explained as social behaviour. Conspecific density has been shown to be a particularly strong proximate and ultimate factor acting on several individual/population features; thus, it may be expected to affect vocal behaviour too. Here, I investigate the hypothesis that, in long‐lived, territorial species, density affects the vocal displays of mated males, masking their honesty as a possible signal of male/territory quality. Each month I listened to the dusk calls of 17 breeding male Eurasian Eagle Owls Bubo bubo during their prelaying period. Nine males bred in a low‐density situation, the other eight in a high‐density one. Conspecific density was found to affect the honesty of call features as signals of male and/or territory quality. The call display as a reliable predictor of male fitness measured as productivity persisted only in situations of high breeding owl density, where male–male competition was stronger. Accommodation of call activity allows individuals to minimize the costs of aggressive calling by adjusting the territoriality threshold to local conditions. The results of this study emphasize the importance, when investigating the evolution and maintenance of honest territorial or sexual signals, of considering the environmental and social context experienced by the individual, thereby corroborating the idea that male–male competition contributes to the maintenance of honest signalling.
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.
Soil particle composition affects the physical characteristics of Sand Martin Riparia riparia holes
Authors: Heneberg P.
Published: July 2003

The importance of correlations between soil particle composition and the physical characteristics of Sand Martin Riparia riparia breeding holes has received very little attention. I used dry sieve analysis and decantation to examine 14 particle size ranges of samples from 654 breeding holes collected at 106 breeding colonies in the Czech Republic and at three in Great Britain. All five measured physical characteristics (tunnel depth, width and height of the entrance opening, slope of the tunnel and the distance to the bank top) were significantly correlated with measured soil particle size ranges. Tunnel depth, which is one of the most important factors influencing breeding success in this species, increased as the proportion of small particles (<900µm) in the soil increased.
The decline of the Spotted Flycatcher Muscicapa striata in the UK: an integrated population model
Authors: Freeman S. N. , Crick H. Q. P.
Published: July 2003

The Spotted Flycatcher has become a species of great conservation concern in Europe and the UK following a period of prolonged and accelerating decline. We consider a range of population models for UK census data between 1965 and 1996, along with independent survey data designed to estimate demographic parameters. Population declines are similar in the major habitats and regions of the UK, indicating that a broad‐scale factor has influenced the population. Nest record data show that changes in individual nest success are not the cause of the increasing decline. This is more likely the result of a fall in the survival rates of fledged birds prior to the next breeding season; we show by comparison with the recoveries of ringed birds that the most likely cause is an increased mortality rate of birds either shortly after fledging or within the subsequent first year of life.
Social interactions among breeding Brünnich's Guillemots Uria lomvia suggest constraints in relation to offspring vulnerability
Authors: Kober Kerstin , Gaston Anthony J.
Published: July 2003

Brünnich's Guillemots Uria lomvia are adapted to high‐density breeding in large colonies on steep cliffs. Because they breed on narrow ledges, egg loss through dislodgement is an important cause of breeding failure. Fighting among breeders presumably raises the risk of accidental dislodgement. In this study, we investigated whether social behaviour among Brünnich's Guillemots shows any adaptations to reduce accidental egg loss by modifying behaviour during incubation. We found that the amount of aggression increased significantly at the time of hatching, perhaps in response to the reduced risk of breeding failure through dislodgement of a chick, compared with an egg. Allopreening followed an inverse trend, falling significantly after the day of hatch. This supports the hypothesis that allopreening is used to reduce aggressive interactions. At the same time, the frequency of allopreening was greatly increased on days when mosquitoes affected the birds, consistent with the hypothesis that allopreening is part of a defence strategy against ectoparasites.
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.
Density‐dependent mortality of wintering DunlinsCalidris alpinathrough predation by Eurasian SparrowhawksAccipiter nisus
Authors: Whitfield D. Philip
Published: July 2003

Density‐dependent mortality in wintering shorebirds is critical to shorebird population dynamics, but is difficult to study and demonstrate. Most winter mortality of small shorebirds probably results from predation by raptors. Over 13 winters, I studied Eurasian SparrowhawkAccipiter nisuspredation on wintering DunlinsCalidris alpinaat a rocky shore in south‐east Scotland, a site apparently of marginal suitability for wintering Dunlins. Most Dunlins on the study site were juveniles (first winter birds), and winter juvenile mortality rate due to Sparrowhawk predation was strongly and positively related to Dunlin density (maximum winter count). There was no indication of any marked effect of weather on Dunlin winter mortality rate, except that mortality was slightly greater in winters with lower temperatures. Dunlin mortality was unrelated to the mortality through Sparrowhawk predation of a preferred prey, the RedshankTringa totanus, or to sighting rates of hawks, suggesting that increased hunting of Redshanks by hawks or a numerical response by hawks were not involved in density‐dependent mortality of Dunlins.
Date and parental quality effects in the seasonal decline in reproductive performance of the Tree Swallow Tachycineta bicolor: interpreting results in light of potential experimental bias
Authors: Wardrop Sharilynn L. , Ydenberg Ronald C.
Published: July 2003

In many bird species early breeders have higher reproductive performance than late breeders from the same population. This could be caused by a reduction in environmental factors related to date per se (Date Hypothesis), or because poorer performers nest later (Parent Quality Hypothesis). We manipulated hatch date of Tree Swallows Tachycineta bicolor by switching clutches with different lay dates, generating broods with advanced or delayed timing, and assessed the impact of the experiment on nestling mass. The Date Hypothesis better explained the decline in nestling mass in the first half of the season, while the Parent Quality Hypothesis was supported in the second half. We also found that female mass loss was unintentionally reduced in advanced females and suggest that such impacts of the experiment on parent quality, or correlations between nestlings and their actual parents via heritability or maternal effects, could bias hatch‐date manipulation experiments towards supporting the Date Hypothesis. Differential costs of incubation, either due to naturally low temperatures early in the season, or due to the unintentional manipulation of female incubation costs, appear to have driven support for the Date Hypothesis early in the season.
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.
Wingtip shape and flight performance in the European Starling Sturnus vulgaris
Authors: Swaddle John P. , Lockwood Rowan
Published: July 2003

Although wingform is known to differ among individuals of the same species it is not known how intraspecific variation in wingtip shape is associated with flight performance. In this study, we have examined both among‐ and within‐individual variation in wingtip shape in relation to changes in flight performance in the European Starling Sturnus vulgaris. We found that level flapping‐flight speed and the ability to negotiate an aerial obstacle course were unrelated to wingtip shape. However, take‐off parameters did vary with wingtip shape; birds with more rounded wingtips tended to take off from the ground at a steeper angle of ascent than those with relatively more pointed wingtips. The same relationships between wingtip morphology and flight were present in both the inter‐ and intra‐individual experimental analyses. The evolutionary importance of this variation in take‐off ability is discussed in terms of predator avoidance and enhancement of individual survival.
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.
Heart Rate Variability Before Ventricular Arrhythmias in Patients with Coronary Artery Disease and an Implantable Cardioverter Defibrillator
Authors: Copie Xavier , Lamaison Dominique , Salvador Michelle , Sadoul Nicolas , Costa Antoine Da , Fauchier Laurent , Legal François , Heuzey Jean‐Yves Le ,   the VALID Investigators
Published: July 2003

Background: Changes in autonomic regulation of the heart may be responsible for the occurrence of arrhythmias. Although a decrease in 24‐hour heart rate variability is a strong predictor of subsequent arrhythmias in patients with heart disease, many questions remain unanswered concerning changes in heart rate and heart rate variability in the minutes or hours preceding an arrhythmia. The aim of our study was to analyze changes in heart rate and heart rate variability occurring during the 90 minutes preceding an arrhythmia, in patients with coronary heart disease and an implantable defibrillator.

Materials and Methods: Thirty‐eight patients, with a total of 93 episodes of ventricular arrhythmia, were included in the study. Heart rate and heart rate variability were measured in three 30‐minute and five 2‐minute periods preceding the arrhythmia. Heart rate variability was assessed using measurements of Poincaré plots.

Results: The results show a gradual increase in heart rate before the arrhythmia, from 73 ± 13/min, to 75 ± 14/min, and finally 78 ± 15/min in the 90 minutes preceding the arrhythmia (P < 0.05).

Conclusion: Measurements of Poincaré plots showed a significant increase in their length and no significant change in their width. These results suggest that sympathetic activation is the predominant change in autonomic nervous system before a ventricular arrhythmia in patients with coronary heart disease. This change may occur as early as one hour and a half before the arrhythmia.
Diagnostic Value of aVL Derivation for Right Ventricular Involvement in Patients with Acute Inferior Myocardial Infarction
Authors: Turhan Hasan , Yilmaz M. Birhan , Yetkin Ertan , Atak Ramazan , Biyikoglu S. Funda , Senen Kubilay , Ileri Mehmet , Cehreli Sengul , Korkmaz Sule , Kutuk Emine
Published: July 2003

Background: Right ventricular (RV) involvement is associated with increased morbidity and mortality in patients with acute inferior myocardial infarction (MI). Although electrocardiography is probably the most useful, simple, and objective tool for the diagnosis of acute MI, there are no well‐defined criteria in the standard 12‐lead electrocardiogram to properly identify RV involvement in patients with acute inferior MI. Our objective was to evaluate the value of ST‐segment depression in lead aVL in diagnosing RV involvement in patients with acute inferior MI.

Materials and Methods: Sixty‐seven patients, hospitalized with acute inferior myocardial infarction, were included in this study. The diagnosis of acute inferior myocardial infarction was based on the clinical history, characteristic enzyme pattern of CK‐MB values, and the appearance of ST‐segment elevation ≥ 1 mm in at least two of the leads (leads II, III, aVF). RV infarction was defined by ST‐segment elevation ≥ 1mm in lead V4R. ST‐segment depression in lead aVL that is more than 1 mm was accepted as a diagnostic criterion for RV involvement in patients with acute inferior MI.

Results: Thirty‐one patients had >1 mm ST‐segment depression and 28 of them had right ventricular infarction according to lead V4R. Thirthy‐six patients showed ≤1 mm ST‐segment depression indicating no right ventricular involvement but four of them also had right ventricular infarction according to V4R.

Conclusion: More than 1 mm ST‐segment depression in lead aVL was found to have high sensitivity (87%), specificity (91%), high positive and negative predictive value (90%, 88%, respectively), and high diagnostic accuracy (89%) in diagnosing RV involvement in patients with acute inferior MI. Therefore, by using a simple 12‐lead electrocardiographic sign, ST‐segment depression >1 mm in lead aVL, obtained on admission, it is possible to identify RV involvement in patients with acute inferior MI.