bluuebunny/crossref_metadata_2025 huggingface dataset:
Predominance of rhinovirus in the nose of symptomatic and asymptomatic infants
Authors: Van Benten Inesz , Koopman Laurens , Niesters Bert , Hop Wim , Van Middelkoop Barbara , De Waal Leon , Van Drunen Kees , Osterhaus Albert , Neijens Herman , Fokkens Wytske
Published: December 2004

Respiratory infections in infancy may protect against developing Th2‐mediated allergic disease (hygiene hypothesis). To estimate the relative contribution of particular viruses to the development of the immune system and allergic disease, we investigated longitudinally the prevalence of respiratory viral infections in infants. One hundred and twenty‐six healthy infants were included in this prospective birth cohort study in their first year of life. Physical examination was performed and nasal brush samples were taken during routine visits every 6 months and during an upper respiratory tract infection (URTI) (sick visits). The prevalence of respiratory viral infections in infants with URTI, infants with rhinitis without general malaise and infants without nasal symptoms was studied. Rhinovirus was the most prevalent pathogen during URTI and rhinitis in 0‐ to 2‐year‐old infants (∼40%). During URTI, also respiratory syncytial virus (∼20%) and coronavirus (∼10%) infections were found, which were rarely detected in infants with rhinitis. Surprisingly, in 20% of infants who did not present with nasal symptoms, rhinovirus infections were also detected. During routine visits at 12 months, a higher prevalence of rhinovirus infections was found in infants who attended day‐care compared with those who did not. We did not observe a relation between breast‐feeding or smoking by one or both parents and the prevalence of rhinovirus infections. The parental history of atopy was not related to the prevalence of rhinovirus infection, indicating that the genetic risk of allergic disease does not seem to increase the chance of rhinovirus infections. In conclusion, rhinovirus infection is the most prevalent respiratory viral infection in infants. It may therefore affect the maturation of the immune system and the development of allergic disease considerably.
Microbodies of the alga Chara
Authors: Stabenau Helmut , Säftel Werner , Winkler Uwe
Published: December 2004

Chara fragilis possesses microbodies with a remarkably large size of up to 2 µm in diameter. Many of the organelles contain huge nucleoids of amorphous material or paracrystalline inclusions. After isolation of the organelles by gradient centrifugation the specific density of the microbodies was determined to be 1.25 g cm−3. Catalase, glycolate oxidase and hydroxypyruvate reductase as well as enzymes of the fatty acid β‐oxidation pathway were demonstrated to be constituents of the microbodies in Chara indicating that they are similar to those in green leaves. The data obtained are in agreement with the view that the Charophyceae and especially the algae in the subgroup of Charales are very closely related to the land plants.
Sucrolytic activities during fruit development of Lycopersicon genotypes differing in tolerance to salinity
Authors: Balibrea María E. , Cuartero Jesús , Bolarín María C. , Pérez‐Alfocea Francisco
Published: December 2004

The different growth responses under control and moderate salinity (70 mM NaCl) in relation to the carbon partitioning and sucrose metabolism in developing tomato fruits [20 days after anthesis (DAA), start of ripening and ripe stages] were studied in the cultivated tomato Lycopersicon esculentum Mill (cv. H‐324‐1), in the wild relative species L. cheesmanii (ac. LA‐530) (hexose‐accumulators), L. chmielewskii (ac. LA‐1028) (sucrose‐accumulator) and in two interspecific F1 hybrids (hexose‐accumulators) (F1‐530: H‐324‐1 × A‐530, F1‐1028: H‐324‐1 × A‐1028). The higher salt‐tolerance of the wild species and hybrids with respect to the domestic tomatoes was also observed at the fruit level because these genotypes were less affected in the assimilation of dry weight (DW) under salinity. With the exception of the wild tomatoes, the sink strength, evaluated as the dry matter accumulation rate (mg DW day−1) and the sink activity, evaluated as a relative growth rate (mg DW mg−1 day−1), were reduced during the early fruit growing period (20 DAA–start ripening). However, a total recovery of growth was registered in the salinized hybrid fruits during the late growing period (start of ripening‐ripe fruits). The early reduction in sink activity in the hybrid and domestic fruits was related to a sucrose accumulation and a decrease in the total sucrolytic activity at 20 DAA, especially the cytoplasmic sucrolytic activities sucrose synthase (EC 2.4.1.13) and neutral invertase (EC 3.2.1.26). The further recovery in sink strength of the hybrid fruits was related to the maintenance of the insoluble acid invertase (EC 3.2.1.25) and the induction of the cytoplasmic sucrolytic activities, namely at the start of ripening stage, demonstrating the existence of an inverse relationship between these activities, which suggests a regulatory mechanism in order to maintain the sink capacity. The roles of different enzymes in the control of assimilate import under salinity in relation to the sucrose transport and possible regulatory mechanisms are discussed.
Isolation of full‐length cDNAs of two cell cycle control factors from proliferating Chenopodium rubrum cells: A CDKB;1 and a transcription factor E2F
Authors: Fountain Michelle D. , Beck Erwin
Published: December 2004

In all organisms, progression of the cell cycle is associated with phase‐specific transcription of cell cycle genes. From the eight cDNAs hitherto identified as representing cell cycle control genes of Chenopodium rubrum, two are new, namely a B‐type CDK and an E2F transcription factor, which are reported in this communication. The CDKB;1 was identified by its PPTALRE cyclin binding motif, the conserved ATP‐binding domain, the typical T‐Loop and phosphoregulatory sites. The E2F transcription factor was identified by its DNA‐ and Rb‐binding domain, the conserved leucine zipper and the ‘marked box’. The GenBank accession numbers are AJ278885 and AJ278884, respectively.
Chemical and mutational modification of histidines in violaxanthin de‐epoxidase from Spinacia oleracea
Authors: Emanuelsson Anna , Eskling Marie , Åkerlund Hans‐Erik
Published: December 2004

The violaxanthin de‐epoxidase (VDE) gene from spinach (Spinacia oleracea) was cloned, sequenced (GenBank AJ 250433), and expressed in Escherichia coli. The highest obtained conversion rate of violaxanthin was 86 nmol s−1 per litre of growth medium, corresponding to an amount of active enzyme of 0.4 mg l−1. Sequence comparison between VDE from different species were made and particular interest was focused on four highly conserved histidines (H121,124,167,173) and their possible involvement in enzymatic activity. Chemical modification of the histidines using DEPC or by site‐directed mutations resulted in partial or total inactivation of the enzyme. The chemical modification could be reversed by hydroxylamine treatment, regenerating a large percentage of the original activity. The histidine residues, which are located in pairs close to each other, were pairwise substituted for either alanine or arginine. This resulted in one inactive mutant (H121,124R) and three mutants with very different activities and decreased binding of ascorbic acid, as reflected by an up to four‐fold increase in Km. A substitution of all four histidines for either alanine or arginine resulted in inactive enzymes. Based on these results it is suggested that the histidine residues are important for the activity of VDE.
Changes in isotypes and enzyme activity of apyrase during germination of dark‐grown pea (Pisum sativum) seedlings
Authors: Moustafa Mahmoud F. M. , Yoneda Motohito , Abe Shunnosuke , Davies Eric
Published: December 2004

In the present study we used 2D‐PAGE and Western blotting to investigate the expression of different isotypes of apyrase (EC 3.6.1.5) during imbibition, germination and initial growth of pea (Pisum sativum L. var. Alaska) seedlings in the dark. The 49 kDa apyrase was absent in the 10‐h imbibed embryos, but began to appear after 16 h germination and increased with germination time. By 62 h, there were five isotypes present at pI 5.8, 6.0, 6.3, 6.6 and 6.8, with those at pI 6.0, 6.3, and 6.6 being most abundant and the one at pI 6.3 predominating, whereas the most acidic and basic isotypes were only present in significant amounts in seedlings after 62 h germination. Stems contained all five isotypes and had more pI 6.0, 6.3 and 6.6 isotype than the plumules, whereas in the roots there were very small amounts of all isotypes. Partial amino acid sequencing showed that all isotypes were identical with apy1, not the more recently described apy2. Apyrase activity was absent in imbibed embryos, but increased sharply during germination and reached a maximum after 62 h. Based upon the capability of the enzyme to hydrolyse ATP, CTP, GTP, TTP, UTP, and ADP (but not AMP), its susceptibility to various ATPase inhibitors, and coincidence of expression of the protein and enzyme activity, we estimate that 50–70% of the ATPase activity results from the 49 kDa apyrase. The present results suggest that isotypes of pI 6.0, 6.3, and 6.6 are physiologically important and strongly indicate a crucial role for apyrase in the differentiation and development of pea seedlings.
Expression of Cell Cycle Control factors in non‐dividing and ageing photoautotrophic plant cells
Authors: Fountain Michelle D. , Valdes Oscar , Fettig Sebastian , Beck Erwin
Published: December 2004

In contrast to the closely controlled phenomenon of plant senescence, very little is known about the molecular processes leading to ageing, which is understood as stochastic degeneration. In plants ageing apparently commences when cell division expires. To explore the relation between cell division and ageing, the expression of cell cycle control genes in the course of a batch culture of photoautotrophic cells of Chenopodium rubrum was studied. In a time‐span of 3 months this culture passes through the developmental phases: division (4 weeks), stationary (5 weeks) and ageing (3–4 weeks). Transcripts of 8 cell cycle control genes (cyclins A/B, D2 and D3, an A‐type CDKA and CDKB;1, Rb‐Protein, E2F and of an inhibitor ICDK) could be detected in all stages of the batch culture. Expression of CycD2, CDKB;1 and Rb markedly declined with the transition from the division to the stationary phase of the cell culture and remained low until the cells died. Transcript levels of the A‐type CDK, cyclins A/B and D3, as well as ICDK, passed through a maximum in the division phase but peaked again in the course of the stationary phase. Levels of the E2F transcript were high in the division and the early stationary phase and then stepwise declined. Addition of cytokinin plus auxin (2,4‐D) to the culture during the first week of the stationary phase resulted in a transitory resumption of cell division, or at least of the G1–S‐transition, concomitantly with a temporary increase in the transcript levels of CycD2, CycD3, CycA/B, CDKA and ICDK. Expression of Rb did not substantially change upon supply of the phytohormones and that of the CDKB;1 and E2F was even suppressed. The results show that in the C. rubrum batch culture both the G1‐S and the G2‐M transition were arrested after 4 weeks of cell culture and that this was set by the downregulation of the expression of CycD2 and Rb on the G1‐S‐ and of CDKB;1 on the G2‐M‐transition. Only the lowering of the CycD2 transcript level was reversible with cytokinin and 2,4‐D. The increase of the ICDK‐transcript level during the stationary phase and in particular upon addition of the phytohormones is interpreted with regard to auxin‐triggered cell enlargement in the course of the stationary phase. A signal sequence is concluded, starting from the deterioration of the nutritional situation of the cells in the batch culture, and manifested by the decrease of the endogenous phytohormone levels, that results in a different expression of cell cycle control genes. Such a signal transduction cascade may include other components as well, and may additionally be affected by oxidative stress, which increases upon ageing.
Plankton community structure in fluctuating environments and the role of productivity
Authors: Beisner Beatrix E.
Published: December 2004

Environmental variability in space and time can have significant influences on community structure. Temporal heterogeneity in nutrient supply has been shown in laboratory studies to have strong impacts on the diversity and composition of phytoplankton communities, depending on the scale of fluctuations. This paper extends the work in chemostats in a number of ways: using large‐scale field mesocosms with natural plankton communities exposed to various frequencies of vertical mixing, modifying environmental productivity and incorporating higher trophic levels. The first major question and experiment focus on whether vertical mixing at various frequencies, and the associated nutrient pulse, has similar effects in nutrient‐rich and nutrient‐poor environments for predominantly single trophic level systems. The results indicate that the temporal scale of fluctuation is more of a structuring factor for phytoplankton communities in enriched enclosures, with little response under oligotrophic conditions. The second experiment examines the responsiveness of entire plankton communities (three trophic levels). Major shifts in community structure were absent under both nutrient‐rich and nutrient‐poor conditions. Responses were seen only in the demography of the top trophic level (Chaoborus flavicans). It appears from these experiments that the spatial disruption that accompanies mixing events may be more important than the temporal component (nutrient pulses) for phytoplankton. This appears to be the case only under conditions where natural spatial heterogeneity is high as it is when systems are enriched. When nutrient pulses are small, as they are in oligotrophic systems where recycling is efficient, little phytoplankton community response is observed. Finally, the inclusion of entire plankton food webs here suppressed the effects of the scale of intermittency in water column mixing at both low and high nutrient levels for all but the highest trophic level.
Dynamics of an immune response in house sparrowsPasser domesticusin relation to time of day, body condition and blood parasite infection
Authors: Navarro C. , Marzal A. , De Lope F. , Møller A. P.
Published: December 2004

The T‐cell mediated response to a challenge of the immune system with phytohemagglutinin (PHA) is a common measure used in ecological studies of host‐parasite interactions or parasite‐mediated selection. We investigated the temporal dynamics of this response in house sparrowsPasser domesticusin order to determine factors that contribute to temporal and individual variation in PHA response. After an initial significant increase in response from injection to six hours post‐injection, there was no further significant change in mean response after 12, 24, 36, 48 and 72 hours. Responses at night were consistently stronger than during daytime. Individuals may benefit from producing both a strong and a quick immune response to parasite attacks, although this may be impossible because of the observed positive relationship between maximum response and latency to maximum response. House sparrows withHaemoproteusinfections had lower PHA responses and smaller maximum responses than individuals without infections. Individuals in prime body condition had stronger PHA responses than individuals in poor condition. House sparrows with large diurnal fluctuations in body mass had a weaker maximum response than individuals with small fluctuations. Since individuals withHaemoproteusinfections have large fluctuations in body mass, this result suggests that infected individuals with large fluctuations in mass are unable to mount a strong immune response.
Habitat composition as a determinant of reproductive success of Tengmalm's owls under fluctuating food conditions
Authors: Hakkarainen Harri , Mykrä Sakari , Kurki Sami , Korpimäki Erkki , Nikula Ari , Koivunen Vesa
Published: December 2004

The effect of landscape composition on the breeding success of vole‐eating Tengmalm's owl (Aegolius funereus) was studied in western Finland at five different spatial scales (250–4000 m) around the nests during two consecutive three‐year population cycles of voles. Landscape composition had strongest effects on owl breeding in the decrease phase of vole cycles. Significant variation in owl breeding occurred along the productivity gradient from farmland predominated areas to barren hinterland. Owls tended to produce earlier clutches on territories predominated by agricultural areas in increasing vole years. A similar trend was observed in the decreasing phase of the vole cycle; owls breeding on barren hinterland seemed to delay breeding compared to owls breeding near agricultural areas. Surprisingly, nestling survival and fledgling production in the decreasing phase declined steeply with increasing proportion of farmland. Clutch size was not significantly related to landscape composition. The number of fledglings decreased with increases in clear‐cut and sapling areas in the decrease phase. During the declining years of vole abundance nestling survival increased from western farmland areas towards the eastern outlying district. These results indicate sudden summer decline of vole populations on farmland predominated habitats. This is probably due to that the number of vole‐eating predators, and hence their impact on vole populations is apparently higher in farmland areas than on forested hinterland. This finding gives support for the ‘spill‐over’ hypothesis, which states that predators and their exploitation tends to ‘spill over’ from luxuriant habitats to the barren habitats.
A radiotelemetric study of movements and thermal biology of insular Chinese pit‐vipers (Gloydiusshedaoensis, Viperidae)
Authors: Shine Richard , Sun Li‐xin , Fitzgerald Mark , Kearney Michael
Published: December 2004

Because of their low metabolic costs, ectothermic predators can specialise on prey resources that are available for only a brief period each year. Endemic pit‐vipers (Gloydius shedaoensis) on a small island in north‐eastern China offer an extreme example of this phenomenon, with adult snakes feeding only on seasonally migrating birds that are available for a few weeks in spring and autumn. We surgically implanted radiotransmitters in 16 pit‐vipers, and located the snakes at weekly intervals for the next 12 months to record activity, movements, home ranges, habitat use, body temperatures and associated environmental temperatures. The snakes were extremely sedentary, with daily displacements averaging <2 m and home ranges <0.3 ha. The snakes maintained diurnal body temperatures around 25°C throughout the active season. Diurnal activity was reduced in summer, when birds were unavailable. Males and females were similar in most aspects of their ecology, except that females were often found in trees in autumn (feeding) while males were more often on the ground at this time (probably mate‐searching). Males also tended to shelter under vegetation rather than under rocks. The low vagility, relatively low body temperatures and summer inactivity of these snakes may reduce energy expenditure, and thus facilitate survival in a habitat where food is available only in brief periods several months apart.
Wing morph‐related differences in the walking pattern and dispersal in a flightless bug, Pyrrhocoris apterus (Heteroptera)
Authors: Socha Radomír , Zemek Rostislav
Published: December 2004

We tested the hypothesis that adults of flightless long‐winged (macropterous) and short‐winged (brachypterous) morphs of Pyrrhocoris apterus (L.) (Heteroptera) differ in their walking path characteristics and dispersal ability. Descriptive variables such as the distance moved, mean velocity, time in observation zone, turn angle, angular velocity, meander and sinuosity were computed from walking track data obtained with the use of the computerized system EthoVision. The macropterous bugs differed from the brachypterous ones by higher mean and angular velocity and distance moved, by shorter time spent in the observation zone, and by lower turn angle, meander and sinuosity parameters. The analysis of locomotory tracks revealed that the walking path of macropters is less tortuous than that of brachypters. Estimation of mean spatial displacement distance attained by two wing morphs indicate higher dispersal activity of macropters, and an important role of the macropterous morph in the dispersal strategy of this bug and spreading of the macropterous genotype into new areas. The results obtained are in accordance with our hypothesis that flightless macropters of P. apterus maintain higher dispersal ability than brachypters despite the evolutionary loss of flight capability.
Uncertain biotic and abiotic interactions in benthic communities
Authors: Hagberg Jacob , Jonzén Niclas , Lundberg Per , Ripa Jörgen
Published: December 2004

We analyze marine benthic communities at different sites in Skagerrak with the purpose of understanding the role of exogenous and endogenous factors in explaining the species’ temporal dynamics. The previous finding that the dynamics of these species communities are mainly driven and synchronized by environmental (temperature) forcing was only weakly supported when analyzing single‐species dynamics at five sites where four of the species were present every year. There was no consistent pattern in how the temperature affected the realized per capita growth rate, either across species at a given site, or among sites for a given species. Furthermore, there was no net‐interaction from the community on a given species strong enough to give rise to second‐order dynamics. However, when implementing a Multi Dimensional Scaling (MDS) analysis and incorporating all sampling sites and species ‐we found that the different communities clustered in relation to depth, hence, communities at the same depth were more “similar” than communities at different depth. Revealing the underlying interactions shaping these marine benthic communities is a challenge that calls for an array of various and complementary approaches.
Costs of parasites in common eiders: effects of antiparasite treatment
Authors: Hanssen Sveinn Are , Folstad Ivar , Erikstad Kjell Einar , Oksanen Antti
Published: December 2004

Parasites are exploiting their host for the resources required for the parasite's reproduction and survival. The effects of antiparasitic treatment during incubation on body mass and return rate in female common eiders Somateria mollissima were examined in a two year study (1998 and 1999). There was no effect of treatment on nest success, but unsuccessful females had lower body mass. Treatment had no effect on incubation time, mass‐loss during incubation or return rate among successful birds. However, treatment lead to higher return rate among unsuccessful birds (treated=69%, n=13; controls=18%, n=11). This pattern remained significant also after including the birds that returned two years after the experiment. We suggest that the unsuccessful females are of lower quality and had higher costs from parasite infections than birds which completed incubation, and that the higher return rate for treated unsuccessful females may mean that costs of parasites are substantial, and that the potential fitness gain from investment in parasite defense and avoidance is large.
Population dynamics of microtine rodents: an experimental test of the predation hypothesis
Authors: Sundell Janne
Published: December 2004

One of the most popular hypotheses to explain the 3–5 year vole cycle in Fennoscandia is the predation hypothesis, which emphasises the role of specialist predators, especially small mustelids, in driving the microtine rodent cycle. I have tested this hypothesis in a field experiment with a focus on the interaction between the least weasel (Mustela nivalis nivalis L.) and the field vole (Microtus agrestis L.). The test involved a perturbation of the natural vole‐weasel dynamics by increasing the numbers of predators. In natural cyclic dynamics, the numbers of weasels follow the numbers of voles with a time lag; the delay in the numerical response of the predators essentially leads to the cyclic dynamics. In this experiment, I attempted to eliminate the time lag in predators' numerical response by adding weasels into the system at a point when vole numbers are increasing but weasels are still scarce. The experiment was conducted in three experimental islands (each 5–10 km2) using adjacent comparable islands as controls. Results of the experiment did not provide strong evidence either for or against the hypothesis. Two of three experimental areas did not show a treatment effect, while one area showed an effect in both population dynamics and population structure. Unexpectedly, the previously clearly cyclic dynamics were much less regular in the study areas (and elsewhere in southern Finland) during the period of the experiment.
Inhibition of Amiodarone‐Induced Lung Fibrosis but not Alveolitis by Angiotensin System Antagonists
Authors: Uhal Bruce D. , Wang Rongqi , Laukka Jeremy , Zhuang Jiaju , Soledad‐Conrad Valerie , Filippatos Gerasimos
Published: December 2004

Abstract: Earlier work in this laboratory showed that amiodarone induces apoptosis in alveolar epithelial cells by a mechanism inhibitable by angiotensin system antagonists. A variety of recent studies suggests a critical role for alveolar epithelial cell apoptosis in the pathogenesis of lung fibrosis. On this basis we hypothesized that amiodarone‐induced alveolar epithelial cell apoptosis and lung fibrosis in vivo might be inhibitable by the angiotensin converting enzyme inhibitor captopril or the angiotensin receptor antagonist losartan. Amiodarone‐induced lung fibrosis was induced in male Wistar rats by oral adminstration over six months. Replicate groups of rats received captopril or losartan in addition to amiodarone. Apoptosis was detected by increased total lung activity of caspase 3 and in situ end labeling (ISEL) of fragmented DNA. Collagen was localized and quantitated by the picrosirius red technique. Alveolar epithelial cell apoptosis was detected in amiodarone‐treated animals as early as three weeks after the start of amiodarone administration; by six months exposure, the incidence of alveolar epithelial cell apoptosis was significantly reduced by coadministration of captopril or losartan. Alveolar wall collagen accumulation also was significantly attenuated by captopril (100%) or losartan (74%), but neither agent blunted the accumulation of alveolar macrophages evoked by amiodarone (5.3‐fold at 6 months). Lung neutrophil content was unchanged by amiodarone treatment for three weeks or six months. These results indicate that amiodarone induces alveolar epithelial cell apoptosis in vivo that is inhibitable by angiotensin antagonists. They also support the hypothesis that blockade of angiotensin formation or function attenuates amiodarone‐induced lung fibrosis irrespective of the severity of alveolitis.
Guanylin and its Lysine‐Containing Analogue in the Isolated Perfused Rat Kidney: Interaction with Chymotrypsin Inhibitor
Authors: Santos‐Neto Messias S. , Carrithers Stephen L. , Carvalho André F. , Monteiro Helena S. A. , Greenberg Richard N. , Forte Leonard R. , Fonteles Manassés C.
Published: December 2004

Abstract: Guanylin and uroguanylin are two novel peptides that activate membrane‐bound guanylate cyclases found in the kidney and intestine, influencing fluid and electrolyte homeostasis by cyclic GMP. Their natriuretic and kaliuretic activities are well documented. Since guanylin is inactivated by chymotrypsin in vitro, experiments were designed to evaluate the role of chymotrypsin‐like proteases in renal metabolism of guanylin. Using the isolated perfused rat kidney, guanylin and a recombinant derivative containing a lysine residue in the N‐terminus of the native peptide was tested. There were three experimental groups. In the first group, lys‐guanylin (0.1–2.5 μg/ml) was placed into perfusate reservoir. In the second group, chymostatin (6 μg/ml), a chymotrypsin inhibitor, was placed into solution. In the third group, after 30 min. of perfusion with chymostatin (6 μg/ml), guanylin (0.3 μg/ml) was placed into solution. A maximal decrease in fractional Na+ reabsorption (%TNa+) was achieved at 1.0 μg/ml of lys‐guanylin (from 73.25±2.29 to 54.97±0.10, P<0.05). Lys‐guanylin (1.0 μg/ml) also decreased fractional K+ reabsorption (%TK+) from 59.26±3.93 to 30.75±0.78 (P<0.05). Chymostatin had no detectable effects in electrolyte reabsorption in this assay. When introduced after chymostatin, guanylin lowered %TNa+ (from 81.2±1.86 to 72.6±2.45, P<0.05) and %TK+ (from 69.4±4.12 to 65.8±2.81, P<0.05). At this subthreshold concentration, guanylin alone lacks effects in %TNa+ or %TK+. Furthermore, the ability of both peptides to promote increases in intestinal fluid secretion was evaluated in the in vivo suckling mouse model. When administered per os, guanylin failed to stimulate intestinal secretion. When chymostatin was present in the test solution, guanylin induced intestinal secretion in this assay. In marked contrast, lys‐guanylin alone induced diarrhoea in the suckling mouse. The present paper concludes that guanylin undergoes metabolism in target tissues such as the intestine and kidney and its lysine‐containing analogue retains full biological activity.
α‐Adrenoceptor‐Mediated Modulation of 5‐HT2 Receptor Agonist Induced Impulsive Responding in a 5‐Choice Serial Reaction Time Task
Authors: Koskinen Tiina , Haapalinna Antti , Sirvi Jouni
Published: December 2004

Abstract: The activation of 5‐HT2A receptors has been shown to enhance the probability of premature responding, regarded as a form of motor impulsive behaviour. At the behavioural level, the interaction of α‐adrenoceptors and 5‐HT2 receptors has been linked to head twitch behaviour, regarded as an experimental model of compulsive behaviour. The aim was to determine whether the probability of premature responding induced by an excess activation of 5‐HT2A receptors can be modulated by the blockade of α1‐ or α2‐ adrenoceptors. In the experiments, the 5‐choice serial reaction time task was used to measure attention and response control of the rats. The experiments assessed the effects of (±)‐1‐(2,5‐dimethoxy‐4‐iodophenyl)‐2‐aminopropane hydrochloride (DOI) 0.1–0.2 mg/kg subcutaneously, a 5‐HT2A/2C agonist, and prazosin, an α1–adrenoceptor antagonist, alone or in combination, on the performance of rats. In an additional experiment to examine the possible role of the α2–adrenoceptors, a potent, selective and specific α2–adrenoceptor antagonist, atipamezole, was given alone or in combination with DOI. Results showed that DOI increased the probability of premature responses, but it did not affect the choice accuracy. Prazosin (0.1 or 0.3 mg/kg, subcutaneously), given on its own had no effects on probability of responding prematurely, but prazosin (0.3 mg/kg.) was able to attenuate the DOI‐induced responding. Atipamezole (0.1 mg/kg, s.c.) did not attenuate the effect of DOI on probability of premature responding. When given at lower doses, DOI (0.03 mg/kg) and atipamezole (0.03 mg/kg) synergistically increased the probability of premature responding, whereas a higher dose of atipamezole (0.3 mg/kg) on its own increased the probability of responding prematurely, but this effect was not additive to that of 0.1 mg/kg DOI. These data indicate that 5‐HT2 receptor activation enhances impulsive responding and this effect can be diminished by the blockade of α1‐adrenoceptors. Atipamezole, an α2‐antagonist, enhances the probability of premature responding and shares the mechanism of action with the 5‐HT2 agonist in this respect. These results provide evidence for an interaction between the serotonergic 5‐HT2 receptors and α‐adrenoceptors in the modulation of response control to the motor impulsivity type of behaviour (premature responding) in addition to that of compulsory behaviour (head shakes) found previously.
Relationship between Methamphetamine‐Induced Dopamine Release, Hyperthermia, Self‐Injurious Behaviour and Long Term Dopamine Depletion in BALB/c and C57BL/6 Mice
Authors: Halladay Alycia K. , Kusnecov Alexander , Michna Lauri , Kita Taizo , Hara Chiaki , Wagner George C.
Published: December 2004

Abstract: Differential sensitivity to neurotoxic effects of methamphetamine on striatal dopaminergic neurones between C57BL/6 and BALB/c mice has been established. In the present studies, the interaction of methamphetamine‐induced dopamine release, self‐injurious behaviour, the neural immune response, and the long‐term (3 day) dopamine depletion were examined in these strains after administration of 8 mg/kg methamphetamine. BALB/c mice showed increased hyperthermia compared to the C57BL/6 strain, as well as induction of interleukin‐1β. Additionally, homovanillic acid (HVA) levels, as well as HVA/DA turnover ratios were elevated in the striatum and frontal cortex of BALB/c mice, both compared to untreated mice and to the C57BL/6 strain after a single injection of methamphetamine. Pretreatment with acetaminophen eliminated the methamphetamine‐induced hyperthermia in BALB/c mice and reduced body temperature in C57BL/6 mice. However, acetaminophen pretreatment did not affect any parameters of dopaminergic toxicity in the striatum or frontal cortex of the BALB/c strain following repeated methamphetamine injections. Furthermore, acetaminophen pretreatment did not alter the incidence of self‐injurious behaviour in BALB/c mice. Therefore, hyperthermia and methamphetamine‐induced toxicity appear to be independent phenomena while self‐injurious behaviour may provide a better predictor of toxicity, which, in turn, may be related to dopamine release.
010 Late onset congenital erythropoietic porphyria (Günther's disease)
Authors: Kontos A. , Ozog D. , Lim H.W.
Published: December 2004

Congenital erythropoietic porphyria is a rare autosomal recessive disease due to the deficient activity of uroporphyrinogen III synthase, the fourth enzyme in the porphyrin‐heme synthetic pathway. Of the porphyrias, it is the most mutilating type, usually presenting early in life. We present a patient who developed skin fragility of sun‐exposed skin and red urine at the age of 72 years. Porphyrin profile showed plasma maximum fluorescence at neutral pH of 617 nm. In plasma, urine and erythrocytes, the predominant porphyrins were uroporphyrin and coproporphyrin. In all specimens, isomer I predominated. Urine δ‐aminolevulinic acid and porphobilinogen, and erythrocyte uroporphyrinogen decarboxylase levels were within nomal limits. These finding were consistent with congenital erythropoietic porphyria. Thrombocytopenia and myelodysplasia with bone‐marrow sideroblasts were also incidentally discovered. Including our patient, only 12 cases of late onset congenital erythropoietic porphyria have been reported worldwide, with our patient being the oldest. Patients who develop late onset congenital erythropoietic porphyria develop less severe manifestations, possibly due to heterogeneous mutations in the defective enzyme. Of the 12 reported cases, seven had thrombocytopenia, six of which also had myelodysplasia.
015 Two broadspectrum SPF 15 sunscreens offer different protection against UV induced depression of delayed type hypersensitivity response in humans
Authors: Moyal D.
Published: December 2004

Sunscreens are designed to protect against sunburn and their efficacy is indicated by the so‐called sun protection factor (SPF). However this index may be inadequate to provide a relevant measurement of protection against other biological damages induced by UV such as immunosuppression.

We measured in human volunteers the ability of two broad spectrum SPF 15 sunscreens, with different UVA protection levels, to prevent the fall in local delayed type hypersensitivity (DTH) response to recall antigens (Multitest Pasteur/Mérieux) after acute solar simulated UV exposure. We first determined the UVR‐dose needed to induce a significant reduction of DTH response in different groups of 15 volunteers.

Two minimal erythernal dose (MED) were found to be the minimal immunosuppressive dose. This dose induced a 36% average fall in immune DTH response. The lower doses tested (0.5 and 1 MED) were ineffective. Sunscreen treated groups were exposed to a dose equal to 2 MED × SPF of the products. The DTH response was not lowered in the group treated by the product having the highest UVA protection. Conversely the DTH response was significantly reduced by 55.7% in the group treated with the low UVA protection sunscreen.

These data suggest that sun protection factor may not be sufficient to predict the ability of sunscreens to protect the immune system. A measurement of UVA protection may also be necessary as UVA seems to have a low contribution to erythema but strongly affects immune response.
Direct effects on proliferation, antigen expression and melanin synthesis of cultured normal human melanocytes in response to UVB and UVA light
Authors: Abdel‐Naser M. Badawy , Krasagakis Konstantin , Garbe Claus , Eberle Jürgen
Published: December 2004

Background/Purpose: Ultraviolet (UV) radiation; induces a variety of responses in the skin, including tanning and inflammation, and may also act as a carcinogen. As epidermal melanocytes are seen as the major targets of UV light, the present study was conducted to evaluate the direct effects of UVA and UVB irradiation on melanocytes in vitro.

Methods:
Normal human epidermal melanocytes (NHM) were exposed on 3 consecutive days to UVA (0.072–7.2 J/cm2) and UVB (7.2–48 mJ/cm2), respectively, and changes of morphology, cell number, melanin synthesis and antigen expression (APAAP technique) were determined 5 days after the first exposure.

Results:
UVA radiation caused only minimal effects on NHM by slightly inducing expression of the activation marker HMB‐45 and decreasing expression of the proliferation marker Ki‐67. No changes of morphology, cell number or melanin synthesis were detectable with any of the applied doses. On the other hand, UVB radiation significantly induced dendrite formation and decreased the number of NHM in a dose‐dependent manner (74% of the controls at 7.2 mJ/cm2, 64% at 14.4 mJ/cm2 and 28% at 36 mJ/cm2). Significant induction of the activation marker HMB‐45 was found in parallel to decreased expression of the differentiation marker K.1.2.58. UVB doses 9.6 mJ/cm2 also resulted in significant downregulation of the proliferation marker Ki‐67, confirming the data of the cell counts, and melanin content was increased in NHM (20% over the controls, P<0.01) after applying 7.2 mJ/cm2 UVB.

Conclusion:
Our results may suggest that the effect of UVB radiation in skin is due to direct activation of melanocytes, whereas skin tanning caused by UVA is mediated rather in an indirect way.
Developing rice lines possessing neutral alleles at sterility loci to improve the width of compatibility
Authors: Lu C. G. , Zou J. S. , Ikehashi H.
Published: December 2004

To improve the width of compatibility for overcoming various sterilities in inter‐subspecific hybrid rice, some elite lines combining several sterility‐neutral genes were developed and the effects on mitigating various hybrid sterilities were tested. From Akihikari// IR36/Dular, neutral genes at ga11 and six sterility loci, S5, S7, S8, S9, S15 and S16, were combined and elite lines were obtained in their successive progeny. Four of the lines tested were confirmed to combine the neutral alleles S5‐n, S7‐n, S8‐n, S9‐n, S15‐n and S16‐n at the sterility loci and, among them, two harboured an additional gamete abortion‐neutral allele, ga11‐n. F1s, which used the lines and various testers as parents, mitigated the spikelet sterilities by six sterility loci and gamete abortion by a gametophyte gene, ga11. These lines could be selectively used as parents or donors to increase the width of compatibility of rice varieties for improving fertility in inter‐subspecific hybrid rice breeding.
Non‐specific bronchial hyper‐responsiveness in children with allergic rhinitis: Relationship with the atopic status
Authors: Cuttitta Giuseppina , Cibella Fabio , La Grutta Stefania , Hopps Maria R. , Bucchieri Salvatore , Passalacqua Giovanni , Bonsignore Giovanni
Published: December 2004

An increased prevalence of bronchial hyper‐responsiveness (BHR) has been demonstrated in children from a general population, and in non‐asthmatic adults with allergic rhinitis. Thus, also children with allergic rhinitis are expected to be at higher risk of BHR. We evaluated the prevalence of BHR in a sample of non‐asthmatic children with allergic rhinitis by means of the methacholine (Mch) bronchial challenge, and by monitorizing the airway patency using the daily peak expiratory flow variability (PEFv). Fifty‐one children (ranged 6–15 years of age) with allergic rhinitis, ascertained by skin prick test to inhalant allergens, underwent a 14‐day peak expiratory flow monitoring, and a Mch bronchial provocation challenge. Thirty healthy children matched for age, and sex served as control group. Thirty‐one children in the rhinitis group (61%), and six (20%) in the control group were Mch+ (Mch provocative dose causing a 20% fall of forced expiratory volume in 1 s respect to baseline <2250 μg, equivalent to 11.50 μmol). In rhinitic children the PEFv did not significantly differ between Mch+ and Mch− subjects, but the total serum immunoglobulin E (IgE) were higher among Mch+. The persistent form of rhinitis was significantly associated to Mch positivity. Non‐asthmatic children with allergic rhinitis displayed a high prevalence of BHR. The BHR was significantly associated with persistent rhinitis and with higher total IgE levels. Nevertheless, the spontaneous changes in airway patency, as expressed by PEFv, were within normal limits both in Mch+ and Mch− children.
Maternal atopy and the number of offspring: Is there an association?
Authors: Karmaus Wilfried , Eneli Ihuoma
Published: December 2004

We investigated the association between maternal atopy and the number of offspring. In a population‐ and pregnancy‐based survey (part of the European Studies on Infertility and Subfecundity), we obtained information on the number of offspring, adverse pregnancy outcomes, age at pregnancy, and waiting time to pregnancy. The German portion of these surveys also included information on physician‐diagnosis of asthma, atopic eczema, or hay fever. The odds ratio (OR) adjusted for age showed that the number of children was reduced among women with atopy (OR = 0.75, 95% CI: 0.57–0.98 in the pregnancy‐based sample; OR = 0.79, 95% CI: 0.63–0.99 in the population‐based sample). We did not identify other signs of reduced reproductive ability in atopic women. The results provide support for two assumptions: (i) either a lower number of offspring in atopic mothers combined with an increased risk of atopy in offspring of atopic mothers may explain the protective effect of a higher number of siblings on atopy in offspring; or (ii) successive pregnancies may decrease the atopic response of the mother and thus the risk of developing atopy in subsequent offspring.
Sensitization to food and airborne allergens in children with atopic dermatitis followed up to 7 years of age
Authors: Gustafsson Dan , Sjöberg Olof , Foucard Tony
Published: December 2004

Previously we investigated the eczema prognosis and the risk of developing allergic asthma and rhinitis in a cohort of 94 children with atopic dermatitis. In this second study on the same cohort we address the development of sensitization to foods and airborne allergens, risk factors and, the question whether children with atopic dermatitis who will not become sensitized can be recognized early. Children with atopic dermatitis were followed up regularly from infancy or early childhood to 7 years of age with clinical examination and blood sampling. After age 3, skin prick tests with inhalation allergens were performed yearly. In most children both clinical allergy and sensitization to egg and milk were transient but those to peanut were persistent. Eighty per cent of the children became sensitized to airborne allergens and 75% of them noticed symptoms when exposed. Heredity for atopy and eczema, sensitization to hen's egg, and early onset of eczema entailed an increased risk of becoming sensitized. Children never sensitized had late onset of eczema and less heredity for atopic disease but did not differ in other respects from the sensitized children.
Richter syndrome in B‐cell chronic lymphocytic leukemia
Authors: Nakamura Naoya , Abe Masafumi
Published: December 2004

Richter syndrome (RS) is well known as a secondary high‐grade lymphoma, mostly diffuse large B‐cell lymphoma (DLBCL) developed in patients with B‐cell chronic lymphocytic leukemia (B‐CLL). In this review, we describe clinicopathological, histological, immunophenotypical and genetic findings of RS. The patients with RS, regardless of transformation of pre‐existing clone or de novo malignant clone, were resistant to conventional combined chemotherapy and died within months of diagnosis. Molecular techniques can provide convincing results for the clonal relationship of RS to pre‐existing B‐CLL. When RS carries a same rearrangement band or a same sequence as B‐CLL by Southern blotting or nucleotide sequence analyses of immunoglobulin heavy and/or light chain genes, it is suggested to that RS transforms from original B‐CLL. These analyses have showed that approximately two‐thirds of RS cases evolved from a B‐CLL clone. How and where does the B‐CLL clone evolve to RS? The genetic alteration of transforming B‐CLL clone into RS has been addressed. Abnormalities of chromosomes 11 and 14 were most frequently involved in RS, but non‐specific. In addition, RS does not include chromosomal translocation between Ig locus and oncogenes or rearrangements of bcl‐6 gene, both of which were found in some de novo DLBCL. Several candidates, such as mutation of p53 gene and abnormalities of cyclin dependent kinase inhibitor, have been proposed to play an important role in the transformation of a part of B‐CLL. However, there is still uncertainly as to how B‐CLL progresses or develops into RS.
Responsiveness of chemotherapy based on the histological type and Wilms’ tumor suppressor gene mutation in bilateral Wilms’ tumor
Authors: Shibata Rie , Takata Ayako , Hashiguchi Akinori , Umezawa Akihiro , Yamada Taketo , Hata Jun‐ichi
Published: December 2004

To clarify a characteristic of bilateral Wilms’ tumor (WT), we examined the clinical and histological features, chemotherapy response and mutations in Wilms’ tumor suppressor gene (WT1) in five patients. Deoxyribonucleic acid was extracted from peripheral lymphocytes and tumor samples, and direct DNA sequencing was performed to detect WT1 mutations. Paraffin sections were stained with H&E for histological review and immunostained with anti‐WT1, anti‐Ki‐67, anti‐S‐100 protein and antimyogenin antibodies. In contrast to the single case of epithelial‐type WT, the other four cases were fetal rhabdomyomatous nephroblastoma (FRN) or contained a premature skeletal muscle component and appeared to be resistant to chemotherapy because there was no reduction in tumor volume. However, after chemotherapy, most of the tumor components changed into mature striated muscle cells, most of which immunostained almost completely negative for Ki‐67. All four cases had the same point mutation of WT1. From our results, the histological findings correlated with WT1 mutations in bilateral WT. The tumor volume of FRN did not decrease in response to chemotherapy. It is possible to predict the chemotherapy response by examining bilateral WT for WT1 mutations and the histological characteristics of tumors.