bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactive effects of nitrogen deposition, fire and grazing on diversity and composition of low‐alpine prostrate Calluna vulgaris heathland
Authors: BRITTON A. J. , FISHER J. M.
Published: November 2006

Low‐alpine heathlands world‐wide have high biodiversity value but are increasingly impacted by the effects of nitrogen deposition as well as fire and grazing. We conducted a 5‐year fertilization experiment to examine the interactive effects of these three factors on vegetation diversity and species composition.

Factorial combinations of nitrogen addition (0, 10, 20 and 50 kg N ha−1 year−1), burning (burned once or not burned) and grazing (annual clipping, 0% or 12% of current year shoots removed) were applied to internationally important prostrate Calluna–Cladonia heathland in the Cairngorm Mountains, Scotland. Species diversity (higher plants, mosses and lichens) and percentage cover were recorded annually.

Fire had a large effect on vegetation diversity and composition, but both were quick to recover. Species richness recovered within 4 years and vegetation composition was predicted to recover within 7 years. Vegetation composition appeared resilient to the effects of disturbance and there was little invasion by graminoids.

Nitrogen deposition interacted with fire. Burned plots showed no significant effect of nitrogen treatment on species diversity, while the diversity of unburned plots was significantly reduced only 1 year after treatment with 50 kg N ha−1 year−1. After 5 years, significant diversity reductions were seen in the 10 kg N ha−1 year−1 treatment. Impacts of nitrogen on species richness were primarily through reductions in lichen diversity.

Severe winter browning of Calluna vulgaris in plots receiving 50 kg N ha−1 year−1 followed early snowfall in 2002–03. This interaction affected only Calluna vulgaris and may have the potential to trigger species composition changes by reducing the dominance of this species.

Synthesis and applications. Although resilient to small‐scale fires, species richness of low‐alpine heaths is reduced by exposure to low levels of nitrogen deposition (background + 10 kg N ha−1 year−1). The lichen component of the vegetation is most sensitive to additional nitrogen, although higher plants can be affected via interactions with climate. These data support the current critical load of nitrogen for this community of 5–15 kg N ha−1 year−1 and suggest that lichen diversity could be a useful indicator of nitrogen deposition impacts in alpine habitats. Effective conservation of biodiversity in low‐alpine heathland will require action at national and international levels to reduce nitrogen deposition in the many areas where the critical load is currently exceeded.
Variations in bark‐stripping by red deer Cervus elaphus across Europe
Authors: VERHEYDEN HÉLÈNE , BALLON PHILIPPE , BERNARD VALERIE , SAINT‐ANDRIEUX CHRISTINE
Published: November 2006

The literature on bark‐stripping by red deer Cervus elaphus in Europe is reviewed to reveal quantitative variation in this behaviour and relate it to deer density and local characteristics such as dominant tree species, occurrence of artificial feeding, altitude, region and size of the study site. We also review the importance of bark in red deer diets over the seasons and discuss the causes of bark‐stripping, focusing on the significance of bark as food.

Over the 36 sites examined, the rate of bark‐stripping was highly variable (from 0 to 84% of susceptible trees debarked), with less damage in Scotland than in other European sites for which bark‐stripping rates were higher at high red deer density. Altitude, the size of the study site, the number of dominant tree species and the occurrence of artificial feeding do not significantly relate to the rate of bark‐stripping.

Bark sometimes made up a large proportion of red deer diet (> 10%), especially in areas with severe winters (high levels of snow), whereas in study sites with mild winters, bark was practically not eaten at all.

These results suggest that severe bark‐stripping could be related to a reduction in food resource availability. This food availability hypothesis needs to be better documented, dealing particularly with the possible interaction between food availability and red deer density.
Potential host plants of Corythucha arcuata (Het., Tingidae) in Europe: a laboratory study
Authors: Bernardinelli I.
Published: November 2006

Abstract:  The oak lace bug Corythucha arcuata (Say) (Het., Tingidae), native to North America, was found in Europe on Quercus robur L. and other oaks in the spring of 2000. The potential host plant range of this species in Europe and its development time were investigated in a laboratory study. An assay was performed on leaf cuts of different plant species. On the deciduous European oaks (Q. robur, Quercus pubescens Willd, Quercus petraea (Mattuschka) Liebl., Quercus cerris L.), as well as Rubus ulmifolius Schott. and Rubus idaeus L., most of the lace bugs (>50%) reached the adult stage; on Castanea sativa Mill., Rubus caesius L. and Rosa canina L., a reduced number of individuals (<25%) reached the adult stage. No nymphs survived on Quercus rubra L. (mentioned in literature as a host plant), on the evergreen oaks Quercus suber L. and Quercus ilex L., on Malus domestica Borkh. and four tested maple species. On plant species where the lace bug reached the adult stage, the development time varied from 13 to 27 days. On European deciduous oak species, the development time was longer on leaves taken in late summer (September) than on those of late spring (June); on the contrary, such differences were not observed on Rubus species, and Castanea sativa.
Seasonality and host utilization of the invasive fruit fly, Bactrocera invadens (Dipt., Tephritidae) in central Tanzania
Authors: Mwatawala M. W. , De Meyer M. , Makundi R. H. , Maerere A. P.
Published: November 2006

Abstract:  The temporal occurrence of the invasive and economically important pest fruit fly, Bactrocera invadens was studied in three agro‐ecological areas of Morogoro Region, central Tanzania, during 2004–2005. Weekly and monthly trappings were carried out with methyl eugenol, protein bait and synthetic food attractant. Bactrocera invadens was permanently present at low and mid‐altitudes (380–520 m a.s.l.) with peak periods coinciding with the fruiting season of mango (Mangifera indica) and guava (Psidium guajava). At high altitude (1650 m a.s.l.) its incidence was only temporal and apparently the result of dispersal from lower altitudes after the mango fruiting season. Rearing results showed mango, loquat (Eriobotrya japonica), guava and grapefruit (Citrus × paradisi) to be the favoured commercial host fruits. Other Citrus species, cucurbits, papaya (Carica papaya) and avocado (Persea americana) were less favoured.
Behavioural and electrophysiological responses of grape berry moth (Lep., Tortricidae) to selected plant extracts
Authors: Gökçe A. , Stelinski L. L. , Isaacs R. , Whalon M. E.
Published: November 2006

Abstract:  Four non‐host plant extracts from Bifora radians, Arctium lappa, Humulus lupulus and Xanthium strumarium, were tested against adult grape berry moths, Paralobesia viteana, for their potential as repellents or oviposition deterrents. Responses were compared with those elicited by the major component of the P. viteana sex pheromone. Moths of both sexes exhibited varying electroantennogram (EAG) responses from 1.7 to 2.4 mV to volatile odours from plant extracts, with the greatest response to extracts of H. lupulus (2.4 mV). A multi‐arm olfactometer was used to assay the behavioural response of moths to the same treatments. Male moths responded significantly to H. lupulus extract, although their strongest response was to the sex pheromone (30.0%). Female moths showed no behavioural response to the sex pheromone, attracting only 6.7% of moths, but they were attracted to extracts of H. lupulus, X. strumarium and A. lappa, with 25.0%, 21.7% and 15.0% of the released insects responding to these treatments, respectively. Choice tests were conducted to compare oviposition by P. viteana on untreated grapes and on grapes treated with one of the extracts. Despite the attraction in the olfactometer assays, H. lupulus extract significantly reduced egg laying; only 12.5% of the total deposited eggs were laid on berries treated with this extract. The extract of B. radians provided complete protection against oviposition.
Oviposition and flight period of the currant shoot borer Lampronia capitella
Authors: Hellqvist S. , Jirle E. , Löfstedt C.
Published: November 2006

The currant shoot borer, Lampronia capitella (Lep., Prodoxidae), is an important pest of currants, Ribes spp., in northern Europe. Oviposition was studied in cage experiments and the flight period was monitored in field studies using pheromone‐baited traps. Blackcurrant, Ribes nigrum, was the host species in both studies. The total egg supply of females was on average 107 eggs and oviposition started 2–5 days after emergence. About 60% of the eggs were laid during the first day of the oviposition period. Eggs were laid in currant fruitlets, in batches comprising several, usually four to seven eggs. The flight period started shortly after the end of the flowering period of blackcurrant, and lasted for about 3 weeks.
Feeding history effects on feeding responses of Rhagoletis indifferens (Dipt., Tephritidae) to GF‐120 and Nulure
Authors: Yee W. L.
Published: November 2006

Abstract:  Effects of feeding history on feeding responses of western cherry fruit fly, Rhagoletis indifferens Curran, to the commercial protein baits GF‐120 and Nulure were determined in the laboratory. Flies were kept on 5% sucrose alone or yeast extract and sucrose (Y + S) for 3–7 or 14–16 days and exposed to 24‐h‐old GF‐120 or Nulure drops on artificial leaves. Numbers and durations of feeding events on leaves and durations of non‐feeding events were recorded over 1‐h periods. Experiments were also conducted to determine effects of Y + S feeding sequences on responses to Nulure, of starvation after sucrose or Y + S feeding on responses to Nulure, and of feeding history on mortality after exposure to GF‐120 and Nulure. Protein‐deprived flies consistently fed more times on GF‐120 and Nulure than protein‐fed flies and fed longer. One day of exposure to Y + S or 16 h of starvation after exposure to sucrose caused greater feeding on Nulure than 7 days of exposure to Y + S or 16 h of starvation after exposure to Y + S. Durations of non‐feeding events on leaves with sucrose or bait were similar in protein‐deprived and ‐fed flies. Responses of 4‐ to 6‐day‐old flies kept on sucrose to 0‐ and 24‐h‐old GF‐120 or Nulure were similar. More flies kept on sucrose were paralysed or dead at 6–32 h after exposure to GF‐120 or Nulure with spinosad than flies kept on Y + S. Results show that complete or long periods of protein deprivation and starvation after sucrose feeding increased feeding responses to GF‐120 and Nulure. The general lack of differences in durations of non‐feeding events on leaves with sucrose or GF‐120 or Nulure in protein‐deprived and ‐fed flies suggests that most protein‐deprived flies found baits through chance encounters following normal movement.
Molecular Characterization of two Distinct Begomoviruses from Ageratum conyzoides and Malvastrum coromandelianum in China
Authors: Huang J. F. , Zhou X. P.
Published: November 2006

Two weed samples, G52 from Ageratum conyzoides and G87 from Malvastrum coromandelianum, showing leaf curling and vein thickening symptoms were collected in Nanning, Guangxi Province, China. The complete nucleotide sequences of DNA‐A‐like molecules of G52 and G87 were determined to be 2735 and 2745 nucleotides respectively. Both DNA‐A molecules have a genomic organization typical of begomoviruses and share 73.4% sequence identity with each other. Sequence comparisons showed that the DNA‐A of G52 and G87 were most closely related to those of Ageratum yellow vein virus (AYVV; 85% sequence identity) and Tobacco leaf curl Yunnanvirus (75.7% sequence identity) respectively. Further sequence comparisons showed that G52 has arisen by recombination among viruses related to AYVV, Papaya leaf curl China virus and an unidentified Begomovirus species. The molecular data suggest that G52 and G87 are two distinct begomoviruses, for which the names Ageratum leaf curl virus for G52 and Malvastrum leaf curl virus for G87 are proposed. The satellite DNAβ molecule was only found to be associated with G87. G87 DNAβ consists of 1354 nucleotides, and shares the highest nucleotide sequence identity (68.9%) with that associated with Sida yellow vein China virus. A defective DNAβ molecule was also found to be associated with G87.
PCR‐based Detection and Differentiation of Anthracnose Pathogens, Colletotrichum gloeosporioides and C. truncatum, from Vegetable Soybean in Taiwan
Authors: Chen L. S. , Chu C. , Liu C. D. , Chen R. S. , Tsay J. G.
Published: November 2006

Anthracnose of vegetable soybean sometimes occurs in summer and causes severe symptoms and yield loss in southern Taiwan. Despite previous reports that Glomerella glycines and Colletotrichum truncatum were causal agents of soybean anthracnose, C. truncatum and C. gloeosporioides (teleomorph G. cingulata), but not G. glycines, were identified as the major pathogens causing anthracnose on the pods and stems of vegetable soybeans from 2003 to 2005. Most strains of C. truncatum and C. gloeosporioides were derived from diseased pods. Morphological formation of fruiting bodies separates the Colletotrichum isolates into two groups. Colletotrichum truncatum forms acervuli only while C. gloeosporioides produces acervuli and/or perithecia. Based on the sequence variation in the ITS1 and ITS2 regions, C. truncatum isolates were highly similar (99–100% nucleotide identity) while C. gloeosporioides isolates diverged into two separate groups that were not associated with morphotype. For early detection of C. truncatum and C. gloeosporioides infection on vegetable soybean plants, two species‐specific primer pairs Colg 1/Colg 2 (expected size of 443 bp) and Colg 1/CT 2 (375 bp) were designed that allowed differentiation of C. gloeosporioides and C. truncatum in multiplex polymerase chain reaction.
Biomass of Nematode and Associated Roots: A Determinant of Symptom Production in Root Knot Disease of Rice (Oryza sativa L.)
Authors: Singh K. P. , Jaiswal R. K. , Kumar N. , Kumar D.
Published: November 2006

The biomass of Meloidogyne graminicola developing in rice roots was studied in relation to the expression of disease symptoms. The biomass of invading second stage juveniles (0.09 μg) increased to 33 μg on day 16 when adult females were in advance egg laying stage, with an increase of approximately 360‐fold. Initiation of leaf yellowing was related to the ratio between total nematode and total root biomass of rice seedlings. Plants with nematode‐to‐root biomass ratios above 1 : 161 did not show any symptom while those with ratios between 1 : 138 and 1 : 121 exhibited yellowing. Plants with nematode‐to‐root biomass ratios between 1 : 115 and 1 : 60 showed moderate stunting while those with ratios between 1 : 43 and 1 : 20 exhibited severe stunting. The wilting symptoms occurred at or below 1 : 14 nematode‐to‐root biomass ratio. The yellowing of leaves in seedlings inoculated with graded inocula was expressed when the nematode‐to‐root biomass ratios reached to 1 : 136 on day 15 at 1000 J2, 1 : 138 on day 9 at 3000 J2, 1 : 134 on day 7 at 6000 J2 and 1 : 129 on day 5 at 9000 J2 per pot. In rice nurseries, seedlings showing moderate stunting, severe stunting, wilting and wilting with single gall recorded nematode‐to‐root biomass ratios of 1 : 92, 1 : 20, 1 : 12 and 1 : 14 respectively. In severely stunted transplanted rice, the nematode‐to‐root biomass ratio ranged from 1 : 84 to 1 : 75.
Phylogenetic Analysis of Xanthomonas albilineans Strains from Okinawa, Japan, Through a Comparison of the gyrB and rpoD Genes in Geographically Distinct Strains
Authors: Tsushima S. , Shinohara H. , Nakazato T. , Ando S. , Sugisawa T. , Tabei Y.
Published: November 2006

The phylogenetic relationships of Xanthomonas albilineans strains isolated in Okinawa, Japan, between January and March 2002 were investigated by comparing their gyrB and rpoD gene sequences. Partial gyrB and rpoD sequences from 31 X. albilineans strains were determined, including 21 Okinawa strains and 10 geographically distinct strains. The Okinawa isolates formed a homogenous group and correspond to strains from the Caribbean islands (St Lucia and Barbados), Guyana and Sri Lanka. The level of sequence diversity in the gyrB and rpoD genes depended on the geographic origin of the strains, suggesting that sequence analysis of these genes can be useful for differentiating genetic variants within the X. albilineans species.
Reaction of White Guinea Yam (Dioscorea rotundata Poir.) Genotypes to Virus Diseases in Four Agroecological Zones in Nigeria
Authors: Odu B. O. , Asiedu R. , Shoyinka S. A. , Hughes J. d'A.
Published: November 2006

Nineteen white yam (Dioscorea rotundata Poir.) genotypes were grown in four agroecological zones in Nigeria for 2 years to study their responses to yam virus diseases, and to investigate the influence of genotype × environment (G × E) interactions on their reactions to virus infection, using the Additive Main Effects and Multiplicative Interactions (AMMI) Statistical Model. Environments, genotypes and G × E interactions were all highly significant (P < 0.0001) for the virus diseases. The G × E interactions accounted for 21.4% of the treatment sum of squares, and influenced the relative ranking of the genotypes across the eight environments. Genotypes TDr 93‐32 and TDr 93‐27 were identified as the most stable genotypes, while TDr 1621 and TDr 1640 were shown to have resistance to virus diseases. The study also identified Jos with high yam virus disease severity as the most appropriate site for the screening of D. rotundata genotypes.
Occurrence and Variability of Potato yellow vein virus in three Departments of Colombia
Authors: Guzmán M. , Ruiz E. , Arciniegas N. , Coutts R. H. A.
Published: November 2006

Potato yellow vein virus (PYVV) causes dramatic yield reductions in potatoes in Andean countries, particularly Colombia. We tested 250 potato leaf samples suspectedly infected with PYVV from three Colombian Departments and assessed genetic diversity in the coat protein gene of 18 representative isolates by RT‐PCR‐RFLP analysis with HinfI. RFLP profiles revealed that 80% of these isolates had an identical restrictotype while the remaining isolates comprised two further restrictotypes or mixtures of two restrictotypes which included the predominant type and one other type. In samples from the Cundinamarca and Antioquia Departments, all three restrictotypes were detected including mixed infections, whereas in samples from the Narino Department only the predominant restrictotype was detected.
Identification of the Bacterial Leaf Spot Pathogen of Poinsettia in China
Authors: Li B. , Xie G. L. , Zhang J. Z. , Janssens D. , Swings J.
Published: November 2006

Bacterial leaf spot of poinsettia has been first reported in China in 2003 and ascribed to Xanthomonas campestris pv. poinsettiicola following the traditional classification of xanthomonads. The present study was undertaken to elucidate the precise position of the causal bacterium in the newly proposed classification of xanthomonads, three bacterial isolates from China were compared with all known Xanthomonas type strains by a polyphasic approach including carbon source utilization profile, fatty acid methyl esters, analysis of 16S rRNA gene sequence and 16S–23S rDNA intergenic spacer sequences. The results indicated that these Chinese isolates could be further identified as a pathovar of Xanthomonas axonopodis.
Screening of Water Yam (Dioscorea alata L.) Genotypes for Reactions to Viruses in Nigeria
Authors: Odu B. O. , Asiedu R. , Shoyinka S. A. , Hughes J. D'A.
Published: November 2006

Studies were made to identify sources of resistance to yam viruses in Dioscorea alata. Forty genotypes of D. alata were evaluated in both the field and in the screenhouse for reactions to the yam viruses: Yam mosaic virus (YMV), genus Potyvirus; Dioscorea alata virus (DAV), genus Potyvirus; Cucumber mosaic virus (CMV), genus Cucumovirus; and Dioscorea alata bacilliform virus (DaBV), genus Badnavirus. The D. alata genotypes were planted in the field and subsequently scored for virus symptom severity. All the genotypes were also planted in an insect‐proofed screenhouse, and challenged mechanically and by vectors for susceptibility to each of the viruses. Analysis of variance (anova) of the symptom severity scores showed that the genotypes responded differently (P < 0.01) to virus disease in the field. Field evaluation also showed that TDa 291 (a landrace genotype from Puerto Rico), TDa 87/01091, TDa 96‐4, TDa 95‐163 and TDa 289 from Nigeria, and TDa 95‐25 (a landrace genotype from Ghana), had a low virus disease symptom rating. Overall screening results showed that two D. alata genotypes (TDa 289 and TDa 291) are good sources of resistance to YMV, DAV and CMV, and that they are tolerant to DaBV.
Detection and Molecular Characterization of Pepper mild mottle virus in China
Authors: Wang X. , Liu F. , Zhou G. , Li X.‐H. , Li Z.
Published: November 2006

Sweet pepper (Capsicum frutescens) is an important summer and winter vegetable throughout China. Plants showing fruit deformation and mosaic symptoms were frequently observed in several sweet pepper fields and greenhouses during a recent survey. Pepper mild mottle virus (PMMoV) was found in 56 samples (total 165 samples collected from Beijing, Baoding and Huinong) by double antibody sandwich enzyme‐linked immunosorbent assay (DAS‐ELISA). The complete nucleotide sequence of Chinese isolate of PMMoV (PMMoV‐CN) was determined and compared with the sequence of other Tobamoviruses. This is the first report of the complete nucleotide sequence and analysis of genome organization for PMMoV isolated in China.
Defects in Allene Oxide Synthase and 12‐Oxa‐Phytodienoic Acid Reductase Alter the Resistance to Pseudomonas syringae and Botrytis cinerea
Authors: Raacke I. C. , Mueller M. J. , Berger S.
Published: November 2006

Jasmonic acid and its methyl ester are signalling molecules involved in regulating development and stress responses in plants. 12‐Oxo‐phytodienoic acid, a precursor in jasmonic acid biosynthesis, is also biologically active. Both oxylipins accumulate after pathogen infection. To understand the function of 12‐oxo‐phytodienoic acid vs. jasmonic acid in plant pathogen interactions, the susceptibility of the dde2 mutant, defective in 12‐oxo‐phytodienoic acid and jasmonic acid biosynthesis and the opr3 mutant, which synthesizes 12‐oxo‐phytodienoic acid but not jasmonic acid was investigated. dde2 and opr3 were more resistant to Pseudomonas syringae. The effect was stronger in the dde2 mutant as in opr3 indicating that both oxylipins regulate pathogen resistance to P. syringae. dde2 was more susceptible to Botrytis cinerea suggesting that 12‐oxo‐phytodienoic acid is important in mediating the defence against B. cinerea. Expression of Pr1 and Pr2 was increased in both mutants after mock infiltration but not or only slightly enhanced after P. syringae infection.
Participation of bone marrow cells in biliary fibrosis after bile duct ligation
Authors: Asawa Sadanori , Saito Takuro , Satoh Atai , Ohtake Koich , Tsuchiya Takao , Okada Hirokazu , Neilson Erik G , Gotoh Mitsukazu
Published: November 2006

Background and Aim:  Bone marrow derived cells are involved in the process of hepatic fibrosis secondary to chronic injury. However, it is not yet known how quickly this event occurs in acute fibrosis models. The purpose of this study was to determine the role of bone marrow cells in rapid fibrosis following bile duct ligation in mice using green fluorescent protein (GFP) expressing bone marrow cells.

Method:  After whole body irradiation, 1 × 106 donor whole bone marrow cells from green fluorescent protein+/– mice were transplanted into C57BL/6 recipients via the tail vein. Four weeks after bone marrow transplantation, chimeric mice were subjected to common bile duct ligation, and livers of these animals were histologically examined after bile duct ligation using anti‐fibroblast specific protein (FSP)‐1 antibody and anti‐alpha‐smooth muscle actin (α‐SMA) antibody.

Results:  Periductal fibrosis consisting of fibroblast specific protein‐positive cells was demonstrated histologically as early as day 7. Most of the fibrotic cells were green fluorescent protein‐negative, however, a significant number of cells were green fluorescent protein‐positive and some were also anti‐FSP or α‐SMA‐positive.

Conclusion:  Differentiation of bone marrow derived cells into activated fibroblast and myofibroblast‐like phenotypes occurs in the very early course of periductal fibrosis following bile duct ligation, suggesting a new strategy for prevention of biliary fibrosis by inhibiting migration of bone marrow cells to liver.
Effects of a novel histamine H2‐receptor antagonist, lafutidine, on the mucus barrier of human gastric mucosa
Authors: Ichikawa Takafumi , Ota Hiroyoshi , Sugiyama Atsushi , Maruta Fukuto , Ikezawa Tomoaki , Hotta Kyoko , Ishihara Kazuhiko
Published: November 2006

Background and Aim:  Lafutidine is a novel histamine H2‐receptor antagonist used primarily as an antisecretory agent in Japan. Previous human studies have not assessed its gastroprotective effects. The purpose of the present study was to determine the effects of lafutidine on the human gastric mucus layer using both histological and biochemical methods.

Methods:  Of the 14 patients scheduled for gastrectomy who consented to participate, seven were given 14 days of lafutidine 20 mg/day (lafutidine group) and the others received no medication (control group). The surface mucus gel layer in Carnoy‐fixed tissue sections was examined immunohistochemically. Both the thickness of the mucus layer and its mucin content were measured in gastric corpus mucosa.

Results:  There was no detectable difference between the groups in the grade of gastritis or the immunohistochemical staining characteristics. The laminated structure of the surface mucus gel layer was retained after administration of lafutidine and it was thicker than the layer in the control group. The surface layer in the lafutidine group had three‐fold more mucin than that in the control group. There was no difference between the two groups in the mucin content of the deep mucosa.

Conclusion:  Lafutidine, given at clinical dosages, not only inhibits acid secretion but also strengthens the mucus barrier of the human gastric mucosa.
Careful patient selection may improve response rates to infliximab in inflammatory bowel disease
Authors: Pearce Callum B , Lawrance Ian C
Published: November 2006

Background and Aim:  The use of infliximab in the treatment of Crohn's disease (CD) is acceptable and appears to be effective in ulcerative colitis (UC). Careful patient selection, resulting in infliximab only for truly refractory inflammatory bowel disease (IBD), may improve its efficacy. The present study aimed to determine if careful patient selection improved infliximab efficacy in IBD.

Methods:  CD or UC/IBD unclassified patients (Montreal classification) were considered for infliximab treatment only after failure of disease control with conventional therapies and confirmation of active disease. Patients with purely luminal IBD received a single infliximab dose. Patients with fistulizing disease (with or without luminal disease) received infliximab at 0, 2 and 6 weeks. Changes to Harvey Bradshaw (HBI) for inflammatory CD and Colitis Activity Index (CAI) for UC/IBDU were used to determine the response and remission rates. In fistulizing CD, a remission was sustained cessation of drainage and resolution of the fistula. Response was correlated to inflammatory marker levels.

Results:  Seventy IBD patients were treated. In CD, 85.2% (46/54) had active luminal and 40.7% (22/54) had fistulizing disease. In luminal CD, at 8 weeks a single infliximab dose induced remission in 75% (24/32) of patients compared to 92.9% (13/14) after infliximab at 0, 2 and 6 weeks. Fistulizing disease responded in 77.2% (17/22) and remitted in 50% (11/22) of patients at 8 weeks. In UC/IBDU, 75% (12/16) responded and 43.8% (7/16) of patients were in remission at 8 weeks.

Conclusion:  Careful patient selection may improve infliximab's efficacy and clinical remission appears greater after induction with three infliximab doses in CD. Clinical efficacy is suggested for UC/IBDU.
Low prevalence of human T cell lymphotropic virus type 1 infection in patients with gastric cancer
Authors: Hirata Tetsuo , Nakamoto Manabu , Nakamura Masamoto , Kinjo Nagisa , Hokama Akira , Kinjo Fukunori , Fujita Jiro
Published: November 2006

Background and Aim:  There have been few studies on the association between human T cell lymphotropic virus type 1 (HTLV‐1) infection and cancer risk. It is still controversial whether or not HTLV‐1 infection affects the incidence of several cancers. With this background, we aimed to evaluate the relationship between HTLV‐1 infection and the occurrence of several types of cancers.

Methods:  Subjects were 699 patients with cancer aged 50 years and older diagnosed between 1991 and 2004 at the Department of Medicine and Therapeutics, Ryukyu University Hospital, Okinawa, Japan, and 1365 control patients without cancer. The association between HTLV‐1 infection and cancer (biliary tract, pancreatic, esophageal, gastric, colorectal, liver, and lung cancers) was analyzed by logistic regression analysis adjusted for age and sex.

Results:  The infection rate of HTLV‐1 in patients with gastric cancer was significantly lower than in controls (P = 0.01, adjusted odds ratio 0.46). The infection rate of HTLV‐1 was not associated with increased or decreased risk of cancers other than gastric cancer.

Conclusion:  Our study indicated that the prevalence of HTLV‐1 infection in patients with gastric cancer appears to be significantly lower than that in control patients.
Treatment of irritable bowel syndrome with osteopathy: Results of a randomized controlled pilot study
Authors: Hundscheid Henry WC , Pepels Manon JAE , Engels Leopold GJB , Loffeld Ruud JLF
Published: November 2006

Background and Aim:  Effective treatment for irritable bowel syndrome (IBS) is not yet available. Osteopathy is a manual treatment which relies on mobilizing and manipulating procedures in order to relieve complaints. In the present study, a randomized controlled trial was carried out to evaluate the effects of osteopathic treatment for IBS.

Methods:  Eligible IBS patients were randomized between osteopathy and standard care. Follow‐up was 6 months and validated means of follow‐up were used. After 1, 3 and 6 months an overall assessment of symptoms was noted and a symptom score was obtained on a 5‐point Likert scale. Quality of life (QOL) was scored with the standardized IBSQOL 2000 questionnaire and the Functional Bowel Disorder Severity Index was used.

Results:  Twenty patients were randomized into the osteopathy group (OG) and 19 patients were included in the standard care group (SCG). Sixty‐eight percent of patients in the OG noted definite overall improvement in symptoms and 27% showed slight improvement. One patient (5%) was free of symptoms at the end of the study. In the SCG, 18% noted definite improvement, 59% showed slight improvement, and in 17% worsening of symptoms was present. The difference in change in overall symptomatic improvement was statistically significant in favor of the osteopathic treatment (P < 0.006). Mean Functional Bowel Disorder Severity Index (FBDSI) score in the OG decreased from 174 to 74 at 6 months (P < 0.0001). Also, a significant decrease was noted in the SCG from 171 to 119 (P < 0.0001). However, the decrease in the OG was significantly higher compared with the standard treatment (P = 0.02). Mean symptom score in the OG decreased from 9.1 to 6.8 but this did not reach statistical significance. In the SCG, no change in symptom score occurred (8.7 vs 10). At 6 months, the score in the OG was significantly lower (6.8 vs 10; P = 0.02). The QOL score increased in the OG at 111 versus 129 (P < 0.009). In the SCG an increase was also noted, but this was not statistically significant (109 vs 121).

Conclusion:  Osteopathic therapy is a promising alternative in the treatment of patients with IBS. Patients treated with osteopathy overall did better, with respect to symptom score and QOL.
Resistance rate to antibiotics of Helicobacter pylori isolates in eastern Taiwan
Authors: Hu Chi‐Tan , Wu Chao‐Chuan , Lin Chih‐Yung , Cheng Chuan‐Chu , Su Siou‐Cing , Tseng Yi‐Hsiung , Lin Nien‐Tsung
Published: November 2006

Background and Aim:  Prevalence of Helicobacter pylori (H. pylori) strains resistant to metronidazole, clarithromycin and amoxicillin is increasing worldwide. The aim of this study was to determine the antibiotic susceptibility patterns in H. pylori strains isolated from eastern Taiwan.

Methods:  One strain each of H. pylori was isolated from 133 symptomatic patients and subjected to determination of the minimal inhibitory concentration (MIC) by the Epsilometer test (E‐test) for four antibiotics commonly used in the treatment of H. pylori infections.

Results:  None of the strains were resistant to tetracycline. Resistance to metronidazole (8 μg/mL), clarithromycin (1 μg/mL) and amoxicillin (8 μg/mL) was found in 51.9%, 13.5% and 36.1% of the isolates, respectively. Metronidazole‐resistant strains were isolated more frequently from women (49/78; 62.8%) than from men (20/55; 36.4%). Resistance to at least two antimicrobial agents was detected in 33.8% of the isolates. There was a high rate of resistance to both metronidazole and amoxicillin (18.1%).

Conclusions:  Clarithromycin and tetracycline may provide useful components of treatment regimens in eastern Taiwan. In addition, pretreatment microbial susceptibility testing rather than empiric therapy is highly recommended for eradication of H. pylori infection.
Nitric oxide‐induced adenosine inhibition of hippocampal synaptic transmission depends on adenosine kinase inhibition and is cyclic GMP independent
Authors: Arrigoni Elda , Rosenberg Paul A.
Published: November 2006

Adenosine is an important inhibitory neuromodulator that regulates neuronal excitability. Several studies have shown that nitric oxide induces release of adenosine. Here we investigated the mechanism of this release. We studied the effects of nitric oxide on evoked field excitatory postsynaptic potentials (fEPSPs) recorded in the CA1 area of rat hippocampal slices. The nitric oxide donor 1,1‐diethyl‐2‐hydroxy‐2‐nitroso‐hydrazine sodium (DEA/NO; 100 µm) depressed the fEPSP by 77.6 ± 4.1%. This effect was abolished by the adenosine A1 antagonist 8‐cyclopentyl‐1,3‐dipropylxanthine (DPCPX; 400 nm), indicating that the nitric oxide effect was mediated by adenosine accumulation. The DEA/NO effect was unaltered by the 5′‐ectonucleotidase inhibitor α,β‐methylene‐adenosine 5′‐diphosphate (AMP‐CP; 100 µm), indicating that extracellular adenosine did not derive from ATP or cAMP release. The guanylyl cyclase inhibitor 1H‐[1,2,4]oxadiazole[4,3‐a]quinoxaline‐1‐one (ODQ; 5 µm) did not affect nitric oxide depression of the fEPSPs, indicating that nitric oxide‐mediated adenosine release was not mediated through a cGMP signaling cascade. This conclusion was confirmed by the observation that 8‐(4‐chlorophenylthio)‐guanosine‐3′,5′‐cyclic monophosphate (8‐pCPT‐cGMP; 1 mm) reversibly depressed the fEPSP by 24.9 ± 4.5%, but this effect was not blocked by adenosine antagonists. Adenosine kinase inhibitor 5‐iodotubercidin (ITU; 7 µm) occluded the nitric oxide effects by 74%, suggesting that inhibition of adenosine kinase activity contributes to adenosine release. In conclusion, exogenous nitric oxide evokes adenosine release by a cGMP‐independent pathway. Intracellular cGMP elevation partially inhibits the fEPSP but not through adenosine release. Although a direct block of adenosine kinase by nitric oxide can not be excluded, the depression of adenosine kinase activity may be due to inhibition by its own substrate adenosine.
Calcium‐triggered exit of F‐actin and IP3 3‐kinase A from dendritic spines is rapid and reversible
Authors: Schell Michael J. , Irvine Robin F.
Published: November 2006

The structure of the actin cytoskeleton in dendritic spines is thought to underlie some forms of synaptic plasticity. We have used fixed and live‐cell imaging in rat primary hippocampal cultures to characterize the synaptic dynamics of the F‐actin binding protein inositol trisphosphate 3‐kinase A (IP3K), which is localized in the spines of pyramidal neurons derived from the CA1 region. IP3K was intensely concentrated as puncta in spine heads when Ca2+ influx was low, but rapidly and reversibly redistributed to a striated morphology in the main dendrite when Ca2+ influx was high. Glutamate stimulated the exit of IP3K from spines within 10 s, and re‐entry following blockage of Ca2+ influx commenced within a minute; IP3K appeared to remain associated with F‐actin throughout this process. Ca2+‐triggered F‐actin relocalization occurred in about 90% of the cells expressing IP3K endogenously, and was modulated by the synaptic activity of the cultures, suggesting that it is a physiological process. F‐actin relocalization was blocked by cytochalasins, jasplakinolide and by the over‐expression of actin fused to green fluorescent protein. We also used deconvolution microscopy to visualize the relationship between F‐actin and endoplasmic reticulum inside dendritic spines, revealing a delicate microorganization of IP3K near the Ca2+ stores. We conclude that Ca2+ influx into the spines of CA1 pyramidal neurons triggers the rapid and reversible retraction of F‐actin from the dendritic spine head. This process contributes to changes in spine F‐actin shape and content during synaptic activity, and might also regulate spine IP3 signals.
Chronic inhibition of nitric oxide synthesis enhances both subventricular zone neurogenesis and olfactory learning in adult mice
Authors: Romero‐Grimaldi Carmen , Gheusi Gilles , Lledo Pierre‐Marie , Estrada Carmen
Published: November 2006

The ability to generate new neurons during the course of adult life is preserved in the subventricular zone of the lateral ventricles and the dentate gyrus of the hippocampus in the mammalian brain. These two regions constitute specifically regulated neurogenic niches, and provide newborn neurons involved in olfactory and spatial learning, respectively. Nitric oxide (NO) is a negative regulator of neurogenesis in the subventricular zone, whereas its role in the dentate gyrus remains controversial. Using systemic administration of NO synthase (NOS) inhibitors to chronically inhibit NO production, we increased neural precursor proliferation in the subventricular zone as well as neurogenesis in the olfactory bulb, without modifying the number of mitotic cells or the granular cell layer thickness in the dentate gyrus. The same treatment specifically improved olfactory learning performance, whereas spatial learning and memory was unchanged, thus demonstrating that olfactory memory is closely associated with the level of ongoing neurogenesis in the subventricular zone–olfactory bulb. The anatomical specificity of the NOS inhibitor actions was not due to differences in the availability of NO, as demonstrated by immunohistochemical detection of neuronal NOS and S‐nitrosylated proteins in both regions. Remarkably, the distinct NO sensitivity might result from a differential expression of epidermal growth factor receptor in precursor cells in both regions, as the proliferative effect of NOS inhibitors in the subventricular zone was restricted to the cells that expressed this receptor.
Corticotropin‐releasing factor promotes growth of brain norepinephrine neuronal processes through Rho GTPase regulators of the actin cytoskeleton in rat
Authors: Swinny Jerome D. , Valentino Rita J.
Published: November 2006

Cognitive aspects of the acute stress response are partly mediated through activation of the locus coeruleus (LC)–norepinephrine (NE) system via corticotropin‐releasing factor (CRF). Apart from mediating the acute responses to stress, CRF can mediate the long‐term impact of stress on the brain through its potent modulation of neuronal morphology. Importantly, the cellular pathways engaged by stress in general, and CRF in particular, in remodeling neuronal structure are poorly understood. Here, we demonstrate that apart from its well‐established acute effects on LC neuronal activity, CRF also stimulates growth and arborization of LC neuronal processes. By contrast, urocortin 2 (UCN 2), a related peptide, inhibits outgrowth of such processes. These opposing effects are transduced by a common receptor (CRF1) but distinct intracellular signaling pathways. The structural effects of CRF required protein kinase A and mitogen‐activated protein kinase, as well as Rac1, a member of the Rho family of GTPases that regulates the actin and microtubule cytoskeleton. By contrast, the effects of UCN II were mediated by the protein kinase C and RhoA pathways. This is the first study to link stress‐related substrates to molecular mediators of actin cytoskeletal remodeling in the LC. We propose a model of dynamic LC neuronal plasticity that is reciprocally controlled by CRF and UCN II, eventually determining actin rearrangement by Rho‐specific pathways. By regulating the extension of processes into pericoerulear regions where limbic afferents terminate, these peptides may determine the degree to which the LC–NE system is influenced by limbic structures that mediate emotional expression.
Repetition suppression of induced gamma band responses is eliminated by task switching
Authors: Gruber Thomas , Giabbiconi Claire‐Marie , Trujillo‐Barreto Nelson J. , Müller Matthias M.
Published: November 2006

The formation of cortical object representations requires the activation of cell assemblies, correlated by induced oscillatory bursts of activity > 20 Hz (induced gamma band responses; iGBRs). One marker of the functional dynamics within such cell assemblies is the suppression of iGBRs elicited by repeated stimuli. This effect is commonly interpreted as a signature of ‘sharpening’ processes within cell‐assemblies, which are behaviourally mirrored in repetition priming effects. The present study investigates whether the sharpening of primed objects is an automatic consequence of repeated stimulus processing, or whether it depends on task demands. Participants performed either a ‘living/non‐living’ or a ‘bigger/smaller than a shoebox’ classification on repeated pictures of everyday objects. We contrasted repetition‐related iGBR effects after the same task was used for initial and repeated presentations (no‐switch condition) with repetitions after a task‐switch occurred (switch condition). Furthermore, we complemented iGBR analysis by examining other brain responses known to be modulated by repetition‐related memory processes (evoked gamma oscillations and event‐related potentials; ERPs). The results obtained for the ‘no‐switch’ condition replicated previous findings of repetition suppression of iGBRs at 200–300 ms after stimulus onset. Source modelling showed that this effect was distributed over widespread cortical areas. By contrast, after a task‐switch no iGBR suppression was found. We concluded that iGBRs reflect the sharpening of a cell assembly only within the same task. After a task switch the complete object representation is reactivated. The ERP (220–380 ms) revealed suppression effects independent of task demands in bilateral posterior areas and might indicate correlates of repetition priming in perceptual structures.
Passive avoidance training is correlated with decreased cell proliferation in the chick hippocampus
Authors: Nikolakopoulou A. M. , Dermon C. R. , Panagis L. , Pavlidis M. , Stewart M. G.
Published: November 2006

One‐trial passive avoidance learning (PAL), where the aversive stimulus is the bitter‐tasting substance methylanthranilate (MeA), affects neuronal and synaptic plasticity in learning‐related areas of day‐old domestic chicks (Gallus domesticus). Here, cell proliferation was examined in the chick forebrain by using 5‐bromo‐2‐deoxyuridine (BrdU) at 24 h and 9 days after PAL. At 24 h post‐BrdU injection, there was a significant reduction in labelling in MeA‐trained chicks in both the dorsal hippocampus and area parahippocampalis, in comparison to controls. Moreover, double‐immunofluorescence labelling for BrdU and the nuclear neuronal marker (NeuN) showed a reduction of neuronal cells in the dorsal hippocampus of the MeA‐trained group compared with controls (35 and 49%, respectively). There was no difference in BrdU labelling in hippocampal regions between trained and control groups of chicks at 9 days post‐BrdU injection; however, the number of BrdU‐labelled cells was considerably lower than at 24 h post‐BrdU injection, possibly due to migration of cells within the telencephalon rather than cell loss as apoptotic analyses at 24 h and 9 days post‐BrdU injection did not demonstrate differences in cell death between treatment groups. Cortisol levels increased in the chick hippocampus of MeA‐trained birds 20 min after PAL, suggesting the possibility of a stress‐related mechanism of cell proliferation reduction in the hippocampus. In contrast to hippocampal areas, the olfactory bulb, an area strongly stimulated by the strong‐smelling MeA, showed increased cell genesis in comparison to controls at both 24 h and 9 days post‐training.
Haemodynamic and neural responses to hypercapnia in the awake rat
Authors: Martin Chris , Jones Myles , Martindale John , Mayhew John
Published: November 2006

The relationship between localized changes in brain activity and metabolism, and the blood oxygenation level‐dependent (BOLD) signal used in functional magnetic resonance imaging studies is not fully understood. One source of complexity is that stimulus‐elicited changes in the BOLD signal arise both from changes in oxygen consumption due to increases in activity and purely ‘haemodynamic’ changes such as increases in cerebral blood flow. It is well established that robust cortical haemodynamic changes can be elicited by increasing the concentration of inspired CO2 (inducing hypercapnia) and it is widely believed that these haemodynamic changes occur without significant effects upon neural activity or cortical metabolism. Hypercapnia is therefore commonly used as a calibration condition in functional magnetic resonance imaging studies to enable estimation of oxidative metabolism from subsequent stimulus‐evoked functional magnetic resonance imaging BOLD signal changes. However, there is little research that has investigated in detail the effects of hypercapnia upon all components of the haemodynamic response (changes in cerebral blood flow, volume and oxygenation) in addition to recording neural activity. In awake animals, we used optical and electrophysiological techniques to measure cortical haemodynamic and field potential responses to hypercapnia (60 s, 5% CO2). The main findings are that firstly, in the awake rat, the temporal structure of the haemodynamic response to hypercapnia differs from that reported previously in anaesthetized preparations in that the response is more rapid. Secondly, there is evidence that hypercapnia alters ongoing neural activity in awake rats by inducing periods of cortical desynchronization and this may be associated with changes in oxidative metabolism.