bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiology of maize I: A comprehensive and integrated view of nitrogen metabolism in a C4 plant
Authors: Hirel Bertrand , Martin Antoine , Tercé‐Laforgue Thérèse , Gonzalez‐Moro María‐Begoña , Estavillo José‐Maria
Published: May 2005

Maize (Zea mays L., line F2) plants were grown in the field under high or low fertilization input to monitor the metabolic, biochemical and molecular events occurring in young vegetative leaves and in the different leaf stages along the main axis in plants harvested 15 days after silking. This study shows that in maize which possess large sinks represented by the seeds, nitrogen (N) management is different compared with tobacco in which sink strength is much lower and mostly limited to young developing leaves. Although in young leaves nitrate assimilation predominates in both species, ammonium assimilation exhibits some species‐specific differences with respect to inorganic and organic N metabolite accumulation during leaf ageing. These differences are likely to be related to the high sink strength of the ear in maize, which continuously imports carbon and N assimilates during grain filling. Consequently, a number of cytosolic glutamine synthetase isoenzymes are expressed during leaf ageing to maintain a constant flux of reduced N necessary for the synthesis of organic N molecules used either for leaf protein synthesis or directly translocated to the grain. This situation contrasts with that found in tobacco for which leaf ammonium assimilation in the plastids is shifted to the cytosol during the transition from sink leaves to source leaves. These species‐specific differences for N assimilation and recycling are discussed in relation to the evolution of leaf photosynthetic activity and leaf senescence, which both seem to be largely dependent on the different sink strength in each species.
Two plant Ca2+ pumps expressed in stomatal guard cells show opposite expression patterns during cold stress
Authors: Schiøtt Morten , Palmgren Michael G.
Published: May 2005

Guard cells respond to cold and other stimuli with an oscillating Ca2+ signal, causing an opening or closing of the stomatal pore. However, the molecular basis for the regulation of Ca2+ transients in guard cells has so far not been elucidated. We have localized the expression of two closely related Ca2+‐ATPases, ACA8 and ACA10, to guard cells in Arabidopsis. Whereas ACA8 expression was limited to guard cells and vascular tissues, ACA10 was found to be ubiquitously expressed. Upon cold treatment, the expression of ACA8 was found to be upregulated while that of ACA10 was downregulated. This finding was supported by the presence of the cold responsive C‐repeat/dehydration‐responsive element motif in the ACA8 promoter sequence.
Activity changes of calmodulin and Ca2+‐ATPase during low‐temperature‐induced anthocyanin accumulation in Alternanthera bettzickiana
Authors: Chang‐Quan Wang , Ye‐Feng Zhang , Tao Liu
Published: May 2005

Effect of low temperature on anthocyanin accumulation in seedlings of Alternanthera bettzickiana and activity changes of calmodulin (CaM) and Ca2+‐ATPase under low temperature were studied. Results indicate that the increase of anthocyanin content was obviously paralleled not only by the activity of CaM but also by the activity of Ca2+‐ATPase. In addition, seedlings were pretreated with CaM antagonist [chlorpromazine (CPZ)] before low‐temperature treatment in order to further investigate whether CaM plays a role in anthocyanin accumulation. CPZ pretreatment inhibited the activity of CaM and Ca2+‐ATPase and caused a reduction in anthocyanin levels. Hence, it is concluded that CaM and Ca2+‐ATPase were directly correlated with anthocyanin accumulation under low temperature, Ca2 ± CaM may be involved in low‐temperature signal transduction leading anthocyanin synthesis.
Identification ofLophodermium seditiosumandL. pinastriin Swedish forest nurseries using species‐specific PCR primers from the ribosomal ITS region
Authors: Stenström E. , Ihrmark K.
Published: May 2005

Lophodermium seditiosumis a serious needle pathogen on pine, particularly in nurseries, and there is a need to detect the pathogen during its latent phase. The internal transcribed spacer (ITS) regions of the rDNA ofL. seditiosumandL. pinastriwere amplified with universal primers and sequenced. Sequence comparisons of the two species allowed the design of species‐specific primers for the ITS regions. The primers were between 18 and 24 bp long with a minimum of 3 bp differences between the species. These primer pairs did not give any amplification of DNA from any other of the examined fungal species or from healthyPinus sylvestrisneedles. It was also possible to identify eitherL. seditiosumorL. pinastriin infected needles with and without signs of infection using these primer pairs. The method was found to be very useful for detection of latent infections ofL. seditiosuminP. sylvestrisneedles in nurseries.
Interfertility between North American and European strains of Phlebiopsis gigantea
Authors: Grillo R. , Hantula J. , Korhonen K.
Published: May 2005

Thirteen homokaryotic strains of Phlebiopsis gigantea from Canada, six strains from the US and 10 strains from Europe were paired in all possible combinations in order to determine the degree of interfertility between them. The diagnosis of interfertility was based on the production of heterokaryotic fruit bodies in the pairings. Among the resulting 406 pairings, 253 (62%) fruited. Within the strains originating from Canada, USA and Europe, 64, 80 and 64% of the pairings fruited, respectively. The fruiting frequency in pairings between the Canadian and US strains was 65%, between the Canadian and European strains 55%, and between the US and European strains 67%. True hybridization between the European and North American P. gigantea was shown by analysing the single‐spore progeny using DNA fingerprinting. In spite of the relatively low interfertility in pairings within and between continents, no clear indication of the existence of intersterility groups was found. The low interfertility is probably due to the ageing of the pure cultures and to deficient fruiting ability of certain heterokaryons on agar medium. The results strongly suggest that although the North American and European strains of P. gigantea show some differentiation they can be regarded as belonging to the same biological species.
Factors affecting the fungal colonization of pine lumber
Authors: Strong N. , Webber J. , Eaton R.
Published: May 2005

This study investigated whether the physiological condition of wood influenced patterns of colonization by mould and sapstain fungi. The extent of fungal defacement on sawn pine lumber Pinus nigra var. maritima that had been killed by gamma‐irradiation was compared with the defacement on untreated, still living timber that had been aged for up to 16 weeks prior to being sawn. All the sawn lumber was exposed to the natural inoculum of sapstain and mould fungi in a working sawmill environment over a 4‐week period. The results indicated that the pattern of fungal defacement differed markedly in dead or aged wood compared with untreated wood. Mould fungi were most prevalent on the dead irradiated wood, whereas sapstain fungi dominated the freshly sawn lumber which was still living. The differences appear to be independent of wood moisture content and may be related to the production of inhibitory compounds by living cells in wood as it becomes senescent and dies.
In vitro interactions in artificial and wood‐based media between fungi colonizing stumps of Sitka spruce
Authors: Woods C. M. , Woodward S. , Redfern D. B.
Published: May 2005

Interspecific interactions between fungi that colonize stumps of Picea sitchensis in Scotland were tested in dual cultures on Norkrans agar, spruce sawdust and in autoclaved blocks cut from roots. Isolates were ranked according to competitive ability on the different media, based on their ability to overgrow competitors or to form deadlock interactions. On the defined medium, Phaeolus schweinitzii was the species most able to overgrow competitors, followed by Stereum sanguinolentum and Heterobasidion annosum; Resinicium bicolor was the least able to overgrow competitors on this medium. By contrast, R. bicolor was the most competitive on spruce sawdust medium. Deadlocking interactions were formed most often in dual cultures on Norkrans agar. Observation of hyphal interactions on Norkrans agar under the microscope identified several different response types including growth of thin hyphae compared to control cultures, hyphal coiling, vacuolation of hyphae, hyphal lysis of one competitor and deposition of crystals in the agar. Hymenomycetes caused varying amounts of decay in autoclaved root blocks. Resinicium bicolor was able to replace other species in most co‐inoculations. Stereum sanguinolentum appeared to be the least competitive species in root block inoculations, being replaced by Melanotus proteus and R. bicolor, although interactions with H. annosum varied widely. These results indicate that substrate has a marked effect on interspecific fungal interactions, with wood‐based, particularly intact woody tissues closely matching competitive behaviour displayed in the field.
Pitch canker ratings of longleaf pine clones correlate with Fusarium circinatum infestation of seeds and seedling mortality in containers
Authors: Carey W. A. , Oak S. W. , Enebak S. A.
Published: May 2005

The incidence and severity of pitch canker was rated among 16 clones of mature longleaf pine (Pinus palustris) in a seed orchard and cones were collected from five of those clones across the range of pitch canker disease ratings. Seed were extracted and commercially processed by clone and the percentages contaminated with Fusarium circinatum determined. Seed from each clone were sown either without treatment or with one of three fungicide treatments in a soil‐less mix at a commercial container nursery to evaluate the effects of F. circinatum (syn. F. subglutinans) on seed and seedling survival. The percent of seed with F. circinatum correlated with the pitch canker ratings in the orchard for the year of collection (r = 0.88, p = 0.05) and, when sown without fungicide treatment, with the number of seedlings produced (r = −0.94, p = 0.01) and with seedling mortality after germination (r = 0.92, p = 0.02). The same orchard clones were more symptomatic of pitch canker through three annual surveys. Fusarium circinatum was isolated from a higher percent of seed from more symptomatic clones and a lower percent of their seed produced plantable seedlings. We propose that removing such clones from seed collections should reduce seedling mortality at the nursery.
Food, nutrition, physical activity and the prevention of cancer: a global perspective – the WCRF/AICR second report
Authors: Miles L. M.
Published: May 2005

Summary  The 1997 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) report, Food, Nutrition and the Prevention of Cancer: a global perspective, has become the most authoritative statement on the topic. Since then, new evidence has emerged, and more sophisticated methods of reviewing and assessing the literature have been developed. As a result, WCRF/AICR has invited a new expert panel of scientists, with observers from the United Nations and other international agencies, to work on the production of a second report, due to be published in 2006. In addition, a special methodology task force, commissioned by WCRF, has established a methodology to systematically review the evidence. No such methodology has, up to now, been used for assessing mainly observational data on causation of disease. A portfolio approach to the evidence is used, in which all types of study, with their advantages and disadvantages, contribute to the inference of causation. Seven academic centres from the UK, the USA and continental Europe are using this new methodology to comprehensively review evidence in systematic literature reviews. In a separate process, an expert panel will make conclusions from the systematic literature reviews. Together with other relevant evidence, the panel will use these conclusions as the basis for formulating recommendations. Set against this backdrop, the new report will act as the most authoritative global report ever to be published on the subject of food, nutrition, physical activity and the prevention of cancer. It will form the basis for coherent strategies for cancer prevention and control and will set the scientific agenda for years to come.
A preliminary investigation into the use of multimedia to enhance dietetic management of overweight and obese children: multimedia design for child–dietitian consultations
Authors: Raaff C. A.
Published: May 2005

Summary  This research focuses on an ever‐increasing problem within the UK – that of childhood overweight and obesity. Overweight primary school children, especially those in the 7–11 years age category, find it difficult to discuss issues that concern their weight. Interactive computer‐based images, sound and text (or multimedia) may be an effective communication aid for this population group. It could also help the dietitian to explain beneficial changes to food choices and eating habits. Interest in educational software has led to a number of multimedia programs aimed at helping children with health problems. Research suggests that these computer programs can improve health but are not utilised in clinic settings. One explanation for this lack of use is that they have not been designed for this purpose. The aim of this study is to construct a technology framework for the development of interactive multimedia technology that can be used within dietetic consultations with children. A multimedia software prototype was developed using the framework. Children and dietitians tested the developed prototype and provided feedback, thereby evaluating the validity of the model. Further research is needed to determine whether software developed using this framework, or approach, does enhance dietary management of overweight children.
Restraint, dieting and watching what you eat amongst female students
Authors: Reid M. , Hammersley R. , Rance J.
Published: May 2005

Summary   ‘Watching what you eat’ has been proposed as an activity distinct from dieting (Nichter et al. 1995), although the two are often conflated in nutritional surveys. This study examined the validity of ‘watching’ by relating it to the psychological trait of dietary restraint, which is defined as concern for dieting and weight fluctuation, using the restraint scale from the Dutch Eating Behaviour Questionnaire (DEBQ) (van Strien et al. 1986). Subjects were 153 female undergraduate students who were asked four questions to assess ‘watching’ and ‘dieting’ behaviours and completed the DEBQ which has three separate scales measuring emotional, external and restrained eating behaviour. The majority of the sample reported sometimes watching what they ate, and this was more common than dieting. Non‐watchers had the lowest restraint scores, followed by watchers and dieters who had the highest restraint scores. It is concluded that ‘watching what you eat’ is a normal form of restrained eating distinct from dieting and that the method of asking four simple questions about dietary behaviour can assess level of restrained eating. This distinction may clarify the difference between ‘healthy’ and ‘unhealthy’ dieting.
17β‐oestradiol up‐regulates longevity‐related, antioxidant enzyme expression via the ERK1 and ERK2[MAPK]/NFκB cascade
Authors: Borrás Consuelo , Gambini Juan , Gómez‐Cabrera Ma Carmen , Sastre Juan , Pallardó Federico V. , Mann Giovanni E. , Viña José
Published: May 2005

Females live longer than males. Oestrogens protect females against aging by up‐regulating the expression of antioxidant, longevity‐related genes such as glutathione peroxidase (GPx) and Mn‐superoxide dismutase (Mn‐SOD). The mechanism through which oestrogens up‐regulate those enzymes remains unidentified, but may have implications for gender differences in lifespan. We show that physiological concentrations of oestradiol act through oestrogen receptors to reduce peroxide levels in MCF‐7 cells (a mammary gland tumour cell line). Oestradiol increases MAP kinase (MAPK) activation as indicated by ERK1 and ERK2 phosphorylation in MCF‐7 cells, which in turn activates the nuclear factor kappa B (NFκB) signalling pathways as indicated by an increase in the p50 subunit of NFκB in nuclear extracts. Blockade of MAPK and NFκB signalling reduces the antioxidant effect of oestradiol. Finally, we show that activation of MAPK and NFκB by oestrogens drives the expression of the antioxidant enzymes Mn‐SOD and GPx. We conclude that oestradiol sequentially activates MAPK and NFκB following receptor activation to up‐regulate the expression of antioxidant enzymes, providing a cogent explanation for the antioxidant properties of oestrogen and its effects on longevity‐related genes.
In vivospectrofluorimetry reveals endogenous biomarkers that report healthspan and dietary restriction inCaenorhabditis elegans
Authors: Gerstbrein Beate , Stamatas Georgios , Kollias Nikiforos , Driscoll Monica
Published: May 2005

Autofluorescent lipofuscin and advanced glycation end‐products (age pigments) accumulate with age across phyla, yet little is understood about their formation under physiological conditions and their specific contributions to the aging process. We usedin vivospectrofluorimetry to quantitate autofluorescence in wild‐typeCaenorhabditis elegansand longevity mutants disrupted for distinct aspects of the aging process. In wild‐type animals, age pigments increase into adulthood, accumulating slowly during the reproductive phase and more rapidly during the post‐reproductive period. As in humans, insulin signaling influences age pigment accumulation – mutations that lower efficacy of insulin signaling and extend lifespan [daf‐2(e1370) insulin receptor andage‐1(hx546) PI3‐kinase] dramatically lower age pigment accumulation; conversely, elimination of the insulin‐inhibited DAF‐16/FOXO transcription factor causes a huge increase in age pigment accumulation, supporting that the short‐liveddaf‐16null mutant is truly progeric. By contrast, mutations that increase mitochondrial reactive oxygen species production do not affect age pigment accumulation, challenging assumptions about the role of oxidative stress in generating these speciesin vivo. Dietary restriction reduces age pigment levels significantly and is associated with a unique spectral shift that might serve as a rapidly scored reporter of the dietary restricted state. Unexpectedly, genetically identical siblings that age poorly (as judged by decrepit locomotory capacity) have dramatically higher levels of age pigments than their same‐aged siblings that appear to have aged more gracefully and move youthfully. Thus, high age pigment levels indicate a physiologically aged state rather than simply marking chronological time, and age pigments are valid reporters of nematode healthspan.
Complicating the role of p53 in aging
Authors: Gentry Amanda , Venkatachalam Sundaresan
Published: May 2005

Recently, we described a p53 mutant mouse model (p53+/m mouse model) that presented a paradox, in which tumor free survival was coupled to reduced lifespan instead of extended lifespan (Tyner et al., 2002). The p53+/m mice expressed a truncated p53 transcript attached to a leader sequence and showed a moderate increase in p53 activity. Based on this data we hypothesized that enhanced levels of p53 caused the early aging and cancer resistance phenotypes. This hypothesis was attractive as it indirectly implied a ‘fine tuning’ mechanism of tumor suppressor gene expression to maintain homeostasis at the organismal level (Campisi, 2002; Kirkwood, 2002). Our results also lent support to the evolutionary theory of antagonistic pleiotropy that predicts the deleterious effects of tumor‐suppressor genes later in life (Williams, 1957). These observations notwithstanding, the p53+/m mouse model presented a caveat, in which tumor free survival was coupled to reduced lifespan instead of extended lifespan. Studies in model organisms have shown that enhanced resistance to oxidative stress correlates with increased longevity (Johnson et al., 2002; Murakami et al., 2003). The tumor suppressor functions of p53 overwhelmingly categorize it as a longevity assurance gene and suggest a synergistic effect on lifespan via tumor free survival of the organism. We show that there are 24 genes deleted in the p53+/m mouse model, complicating the role of p53 in aging and raising the possibility that the phenotypes while resembling ‘premature aging‐like’ symptoms, may not be related to the physiological changes seen during normal aging processes.
A proposed set of descriptors for functional senescence data
Authors: Martin Ian , Gargano Julia Warner , Grotewiel Michael S.
Published: May 2005

Declines in function1 are common manifestations of aging in many phyla (Arking, 1998). As functional senescence is thought to drive the increasing risk of death with age, understanding functional senescence is important for understanding aging. Experimental investigation of functional senescence requires one to quantitate and compare age‐dependent declines in function between cohorts. Such quantitation and comparison is often difficult owing to complexities in functional senescence data sets. Here, we discuss issues related to describing and contrasting age‐related declines in function.

We parameterized functional senescence data in simple ways to generate descriptors for (1) the rate of functional decline, (2) the time to onset of functional decline and (3) total function. To illustrate how these descriptors can be used, we analyzed a hypothetical data set and one of our previously published data sets (Goddeeris et al., 2003). We conclude that no one descriptor sufficiently characterizes functional senescence. Useful distinctions between functional senescence in different cohorts can be made, however, when multiple descriptors are used in an integrated fashion.
Age‐related changes in regional brain mitochondria from Fischer 344 rats
Authors: LaFrance R. , Brustovetsky N. , Sherburne C. , DeLong D. , Dubinsky J. M.
Published: May 2005

Brain mitochondrial function has been posited to decline with aging. In order to test this hypothesis, cortical and striatal mitochondria were isolated from Fischer 344 rats at 2, 5, 11, 24 and 33 months of age. Mitochondrial membrane potential remained stable through 24 months, declining slightly in mitochondria from both brain regions at 33 months. The ability of calcium to induce mitochondrial swelling and depolarization, characteristics of the permeability transition, was remarkably stable through 24 months of age and increased at advanced ages only for cortical, but not striatal, mitochondria. Striatal mitochondria were more sensitive to calcium than were cortical mitochondria throughout the first 2 years of life. A two‐fold increased resistance to calcium was observed in striatal mitochondria between 5 and 11 months. Although these measurements do demonstrate changes in mitochondrial function with aging, the changes in polarization are relatively small and the increased cortical susceptibility to the permeability transition only occurred at very advanced ages. Thus mitochondrial decline with advanced age depends upon brain region.
UCP1 deficiency increases susceptibility to diet‐induced obesity with age
Authors: Kontani Y. , Wang Y. , Kimura K. , Inokuma K.‐I. , Saito M. , Suzuki‐Miura T. , Wang Z. , Sato Y. , Mori N. , Yamashita H.
Published: May 2005

Loss of nonshivering thermogenesis in mice by inactivation of the mitochondrial uncoupling protein gene (Ucp1−/– mice) causes increased sensitivity to cold and unexpected resistance to diet‐induced obesity at a young age. To clarify the role of UCP1 in body weight regulation throughout life and influence of UCP1 deficiency on longevity, we longitudinally analyzed the phenotypes of Ucp1−/– mice maintained in a room at 23 °C. There was no difference in body weight and lifespan between genotypes under the standard chow diet condition, whereas the mutant mice developed obesity with age under the high‐fat (HF) diet condition. Compared with Ucp1+/+ mice, Ucp1−/– mice showed increased expression of genes related to thermogenesis and fatty acid metabolism, such as β3‐adrenergic receptor, in adipose tissues of the 3‐month‐old mutants; however, the augmented expression was reduced in Ucp1+/+ mice in 11‐month‐old Ucp1−/– mice fed the HF diet. Likewise, the increased levels of UCP3 and cAMP‐dependent protein kinase in the brown adipose tissue of Ucp1−/– mice given the standard diet were decreased significantly in that of Ucp1−/– mice fed the HF diet, which animals showed impaired norepinephrine‐induced lipolysis in their adipose tissues. These results suggest profound attenuation of β‐adrenergic responsiveness and fatty acid utilization in Ucp1−/– mice fed the HF diet, bringing them to late‐onset obesity. Our findings provide evidence that UCP1 is neither essential for body weight regulation nor for longevity under conditions of standard diet and normal housing temperature, but deficiency increases susceptibility to obesity with age in combination with HF diet.
Ursodeoxycholic acid in the treatment of intrahepatic cholestasis of pregnancy.
Authors: Zapata Rodrigo , Sandoval Lorena , Palma Joaquìn , Hernández Ismael , Ribalta José , Reyes Humberto , Sedano Manuel , Tohá Dolores , Silva Juan Jorge
Published: May 2005

Abstract: Objective: To assess the efficacy of ursodeoxycholic acid (UDCA) in patients with intrahepatic cholestasis of pregnancy (ICP) and in the outcome of pregnancy.

Methods: Retrospective analysis of our 12‐year experience treating ICP patients with UDCA. Thirty‐two patients with pruritus starting before week 34 of pregnancy and with increased serum bile salts (BS) and alanine aminotransferase (ALT) received UDCA (15 mg/kg/day) for at least 3 weeks before delivery. They were compared with 16 historical controls who did not receive UDCA. All patients were followed up until delivery and in puerperium. Newborns were followed up during 3 months.

Results: UDCA treatment attenuated pruritus (P<0.05), serum bilirubin and ALT decreased (P<0.05) and BS declined. Delivery at term (≥37 weeks) occurred in 65.7% of UDCA‐treated patients compared with only 12.5% in controls (P<0.01). Infants born to mothers treated with UDCA weighed a mean of 500 g more than the controls (2882±582 vs 2385±582; P<0.01). At 3 months, all infants developed normally. Twenty‐six children whose mothers received UDCA were re‐examined after 1–12 years and they and their mothers were healthy.

Conclusions: UDCA improved pruritus and biochemical cholestasis, and facilitated deliveries at term in ICP patients, with a higher birthweight compared with historical controls. The drug was well tolerated and no adverse effects were detected in their infants.
A multi‐step, incremental expansion method for radio frequency ablation: optimization of the procedure to prevent increases in intra‐tumor pressure and to reduce the ablation time
Authors: Kotoh Kazuhiro , Nakamuta Makoto , Morizono Shusuke , Kohjima Motoyuki , Arimura Eiichirou , Fukushima Marie , Enjoji Munechika , Sakai Hironori , Nawata Hajime
Published: May 2005

Abstract: Background/Aims: Radio frequency ablation (RFA) has been accepted clinically as a useful local treatment for hepatocellular carcinoma (HCC). However, intra‐hepatic recurrence after RFA has been reported. We initially hypothesized that recurrence was attributable to increases in intra‐tumor pressure during RFA, and we subsequently measured the pressure and optimized the procedure.

Methods: A block of pig liver sealed in a rigid plastic case was used as a model of an HCC tumor with a capsule. We compared the pressure between a single‐step full expansion of the needle (single‐step method) and incremental, stepwise expansion (multi‐step method), and evaluated the effect of varying the electrical power. Finally, we performed a preliminary comparison of the ablation times for these methods in HCC cases.

Results: The multi‐step method resulted in a significantly lower pressure and shorter total ablation time than the single‐step method. Furthermore, incremental expansion in 10 steps resulted in a lower pressure and shorter ablation time than four steps. Seventy W‐ablation resulted in a lower pressure and shorter time than 30‐ or 50 W‐ablation. In HCC cases, the multiple‐step method had a significantly shorter ablation time than the single‐step method.

Conclusion: The multi‐step method can be recommended to reduce the ablation time, and suppress the increase in pressure.
Vascular, hemodynamic and renal effects of low‐dose losartan in rats with secondary biliary cirrhosis
Authors: Heller Jörg , Trebicka Jonel , Shiozawa Thomas , Schepke Michael , Neef Markus , Hennenberg Martin , Sauerbruch Tilman
Published: May 2005

Background: In cirrhosis, splanchnic and systemic vasodilatation induce a hyperdynamic circulatory dysfunction, portal hypertension and renal sodium retention. This vasodilatation is in part because of an impaired vascular response to α1‐adrenoceptor agonists. Recently, the angiotensin II type 1‐receptor antagonist losartan has been shown to attenuate portal hypertension. We hypothesized that losartan decreases portal pressure by counteracting the impaired vascular responsive to α1‐adrenoceptor agonists.

Methods: We studied, in rats with secondary biliary cirrhosis and sham‐operated rats, the effect of 0.5 and 10 mg losartan/kg × day on aortic responsiveness to α1‐adrenoceptor stimulation with methoxamine and angiotensin II (myograph), splanchnic and systemic hemodynamics (colored microspheres), plasma noradrenaline levels and kidney function.

Results: In cirrhotic rats, 10 mg losartan/kg × day completely inhibited aortic contractility to angiotensin II, decreased vascular resistance and arterial pressure and induced renal failure. In contrast, 0.5 mg losartan/kg × day only partially inhibited aortic contractility to angiotensin II, but improved aortic contractility to methoxamine, increased splanchnic and systemic vascular resistance, decreased portal pressure, decreased plasma norepinephrine levels and induced natriuresis.

Conclusions: In cirrhotic rats, losartan at a very low dose increases splanchnic vascular resistance, decreases portal pressure and improves kidney function, possibly by an increased vascular responsiveness to α1‐adrenoceptor agonists.
Interferons α, β, γ each inhibit hepatitis C virus replication at the level of internal ribosome entry site‐mediated translation
Authors: Dash Srikanta , Prabhu Ramesh , Hazari Sidhartha , Bastian Frank , Garry Robert , Zou Weiping , Haque Salima , Joshi Virendra , Regenstein Fredric G. , Thung Swan N.
Published: May 2005

Abstract: Interferon (IFN)‐α is the standard therapy for the treatment of chronic hepatitis C, but the mechanisms underlying its antiviral action are not well understood. In this report, we demonstrated that IFN‐α, ‐β and ‐γ inhibit replication of the hepatitis C virus (HCV) in a cell culture model at concentrations between 10 and 100 IU/ml. We demonstrated that the antiviral actions each of each these IFNs are targeted to the highly conserved 5′ untranslated region of the HCV genome, and that they directly inhibit translation from a chimeric clone between full‐length HCV genome and green fluorescent protein (GFP). This effect is not limited to HCV internal ribosome entry site (IRES), since these IFNs also inhibit translation of the encephalomyocardititis virus (EMCV) chimeric mRNA in which GFP is expressed by IRES‐dependent mechanisms (pCITE‐GFP). These IFNs had minimal effects on the expression of mRNAs from clones in which translation is not IRES dependent. We conclude that IFN‐α, ‐β and ‐γ inhibit replication of sub‐genomic HCV RNA in a cell culture model by directly inhibiting two internal translation initiation sites of HCV‐ and EMCV‐IRES sequences present in the dicistronic HCV sub‐genomic RNA. Results of this in vitro study suggest that selective inhibition of IRES‐mediated translation of viral polyprotein is a general mechanism by which IFNs inhibits HCV replication.
Burnout as a developmental process among Japanese nurses: Investigation of Leiter's model
Authors: KITAOKA‐HIGASHIGUCHI Kazuyo
Published: May 2005

Aim:  The first object of the present study was to compare Leiter and Maslach's original model (1988) and the revised model (proposed by Leiter in 1991). The second object was to ascertain whether the process model of burnout proposed by Leiter in 1993 is applicable to Japanese nurses. Workload demand, role conflict, and interpersonal conflict were selected as organizational demands, and supervisor support, coworker support, and occupational decision authority as resources.

Methods:  The subjects were Japanese clinical nurses (n = 238) working at a municipal general hospital. One hundred and eighty‐three effective data was obtained. The hypotheses were tested using structural equation analysis.

Results:  The results supported the revised model which maintained the sequential link from exhaustion to cynicism, but recast the relationship of professional efficacy with another two components of burnout. The hypothesized model was revised based on findings and re‐analysed. The organizational demands exhibited a significant positive correlation to exhaustion. Cynicism exhibited a negative correlation to supervisor support. The job decision authority exhibited a positive correlation to professional efficacy. However, the hypothesis that supervisor support exhibits a positive correlation to professional efficacy was not supported.

Conclusions:  Leiter's process model of burnout is conceptualized based on the conservation of resources (COR) theory. The results of the present study were reasonably in line with the COR theory. It was suggested that Leiter's model should be applicable to Japanese nurses.
Analysis of nutritive sucking function in very low and extremely low birthweight infants in Japan: A pilot study
Authors: MATSUBARA Manami , TAMURA Yasuo , RUCHALA Patsy
Published: May 2005

Aim: The purpose of the present study was to investigate the differences in nutritive sucking patterns between very low, extremely low birth‐weight infants (LBWI) and full‐term infants (FTI) and to examine the change in those sucking patterns within 5 months after birth.

Methods: Sucking patterns of eight LBWI and seven FTI were compared. In addition, sucking patterns were measured in four of the LBWI and seven of the FTI until 5 months of age to determine change in sucking wave patterns over time.

Results: During the first month after birth, there was a significant difference in the sucking wave between the LBWI and FTI. The sucking cycle time was significantly shorter and the intensity of the sucking pressure was significantly smaller in the LBWI than that in the FTI. By 5 months, significant correlations were noted between the actual age or the modified age and the sucking pressure in both LBWI and FTI.

Conclusions: The findings suggest that the weakness of oral muscular function and less sucking skill can bring about the weakness of intensity of sucking pressure, decreased time of the sucking stage in a sucking cycle, and unstable intensity of sucking pressure and time of the sucking stage in LBWI infants, causing low efficiency of milk intake and smaller amounts of milk swallowing during each sucking period as they obstructs the development of oral muscular function itself. These problems last for a longer period of time in LBWI than in FTI, leading to a deficit in the development of masticatory function in LBWI. The results of the current pilot study will serve as a foundation to investigate the development of masticatory function in LBWI as they grow into early childhood.
Learning model and curriculum designs for international health in nursing
Authors: HENRY Beverly , UEDA Reiko
Published: May 2005

Aim:  Nursing's domain of inquiry for international health is unclear. A learning model to frame this specialty is unavailable. The goal of this analysis was to open debate worldwide on the nature of concepts, relationships, and analytic constructs that can serve as a foundational blueprint for international nursing curriculums. The aim was to define and operationalize international health in nursing by constructing a learning model.

Methods:  The exercise was exploratory using content analysis to distinguish key concepts in disciplinary and multidisciplinary documents through relevancy sampling. Sources of certainty were expert knowledge and experience and the embodied practices in international health. Procedures to ensure interrater reliability were used to strengthen confidence in formulating the bases for robust curriculum designs.

Results:  The five main concepts discerned were environment, demography, culture, technology, and research. Nursing goals framed as analytic constructs with amplification serve as the basis for statements of student outcome competencies. The resulting concepts, constructs, and competencies taken together provide a beginning operationalization of international health in nursing for a variety of progressive curriculum designs.

Conclusions:  In Japan, higher education is increasingly international and, for this, clear, agreed‐on academic goals are warranted. Nursing's higher education is obligated to prepare students for a future in environments highly globalised and technological with a culture of tolerance. The model facilitates scholarly debate for a progressive view of international health characterized by emphasis on theory and practical application.
Factors associated with the feeling of stability in the daily life among colostomy patients
Authors: ITO Naomi , KAZUMA Keiko
Published: May 2005

Aim:  Colostomy patients must lead a stable life after discharge. However, little is known about the feeling of stability in the daily life of these patients. The purpose of the present study was to identify the associated factors.

Methods:  The subjects were outpatients who met all of the following criteria: (i) a permanent colostomy for the treatment of colonic, rectal, or anal cancer; (ii) under 80 years of age; (iii) a colostomy history of less than 10 years; and (iv) no significant prior physical or psychiatric disorders. Data were collected by conducting interviews using a questionnaire, examining medical records, and asking the nurses responsible for patients’ care. The following measures were evaluated: patients’ feeling of stability in the daily life, patients’ characteristics, physical condition, support resources, self‐evaluation of their current life, and hospital characteristics. Statistical analysis was performed using t‐tests, Spearman's rank correlation coefficients, and structural equation model.

Results:  Data from 133 patients were available for analysis. The final model fitted the data well. All estimated parameters were significant. The opportunity to attend periodic stoma clinics and support from nurses contributed to the feeling of stability in the daily life and had a positive effect on patients’ self‐evaluation of their current life.

Conclusions:  The results of this study corroborated the necessity for an outpatient support system to enhance the feeling of stability in the daily life after hospital discharge. This finding supports the need to improve stoma care systems and to make such systems more available.
Meaning of health for Japanese elders who have had a stroke
Authors: TAKAHASHI Ryutaro , LIEHR Patricia , NISHIMURA Chie , ITO Mio , SUMMERS Linda C.
Published: May 2005

Aim:  This study was conducted to explore the meaning of health for Japanese elders who have had a stroke.

Methods:  A secondary analysis of existing data was conducted by using phenomenological methods. Twenty‐four male and female stroke patients, whose average age was 76 ± 7.2 years, described the meaning of health with one researcher. Researchers from Japan and the USA analysed the data through email communication and scheduled visits. The five‐step analysis method began from the English transcriptions of descriptions to finally identify a structural definition of health for Japanese elders who have had a stroke.

Results:  The structural definition identifies health as a fundamentally valuable gift recognized by stroke patients as they try to adjust to their present circumstance, defined by their past experience, and as they consider dimensions of everyday living from a new perspective. Judgments about how they are doing are created through the eyes and expressions of others who interact with them and through everyday markers of usual life, like a good appetite, easy breathing and smooth thinking and moving.

Conclusions:  Comparable with other studies, elderly Japanese stroke survivors seek a revised but familiar, stable ‘self’ based on a new frame of reference incorporating their past with the person they are now. Unlike other stroke survivors of previous studies, these Japanese elders considered fundamental human patterns such as breathing and eating as markers for good health, and they used the assessments of others to judge their progress. There is a need for health‐care providers to thoughtfully engage with stroke survivors to determine the most meaningful approaches to care and engagement demands and understand that their interactions are intricately woven into the patient's health experience.
Effects of aided and unaided support of the neck while sitting (with back support), on autonomic nervous system activities
Authors: OKUBO Nobuko , HISHINUMA Michiko
Published: May 2005

Aim:  To compare the effects of neck support and no neck support while sitting (with back support), on the autonomic nervous system for the purpose of developing effective consciousness disturbance nursing techniques based on patient posture.

Methods:  Seven healthy women followed two patterns in a cross‐over design study: (i) sitting in a position with back support but no neck support, sitting with both back and neck support; and (ii) sitting in a position with both back and neck support, sitting with back support but no neck support. The intervention involved unaided support of the subject's neck with each subject supporting their own neck. Coarse Graining Spectral Analysis was used to measure the effect of the two positions on the autonomic nervous system.

Results:  Sitting in a position with back support but no neck support increased the function of the sympathetic nervous system and decreased the function of the parasympathetic nervous system more than sitting in a position with both back and neck support.

Conclusion:  Unaided support of the neck stimulated the autonomic nervous system. We infer from this, therefore, that consciousness disturbance patients may benefit in terms of preventing disuse syndrome and improving their consciousness levels by developing a nursing technique involving unaided support of the neck.
Effect of Unequal Variances in Proficiency Distributions on Type‐I Error of the Mantel‐Haenszel Chi‐square Test for Differential Item Functioning
Authors: Monahan Patrick O. , Ankenmann Robert D.
Published: May 2005

Empirical studies demonstrated Type‐I error (TIE) inflation (especially for highly discriminating easy items) of the Mantel‐Haenszel chi‐square test for differential item functioning (DIF), when data conformed to item response theory (IRT) models more complex than Rasch, and when IRT proficiency distributions differed only in means. However, no published study manipulated proficiency variance ratio (VR). Data were generated with the three‐parameter logistic (3PL) IRT model. Proficiency VRs were 1, 2, 3, and 4. The present study suggests inflation may be greater, and may affect all highly discriminating items (low, moderate, and high difficulty), when IRT proficiency distributions of reference and focal groups differ also in variances. Inflation was greatest on the 21‐item test (vs. 41) and 2,000 total sample size (vs. 1,000). Previous studies had not systematically examined sample size ratio. Sample size ratio of 1:1 produced greater TIE inflation than 3:1, but primarily for total sample size of 2,000.
A Mixture Model Analysis of Differential Item Functioning
Authors: Cohen Allan S. , Bolt Daniel M.
Published: May 2005

Once a differential item functioning (DIF) item has been identified, little is known about the examinees for whom the item functions differentially. This is because DIF focuses on manifest group characteristics that are associated with it, but do not explain why examinees respond differentially to items. We first analyze item response patterns for gender DIF and then illustrate, through the use of a mixture item response theory (IRT) model, how the manifest characteristic associated with DIF often has a very weak relationship with the latent groups actually being advantaged or disadvantaged by the item(s). Next, we propose an alternative approach to DIF assessment that first uses an exploratory mixture model analysis to define the primary dimension(s) that contribute to DIF, and secondly studies examinee characteristics associated with those dimensions in order to understand the cause(s) of DIF. Comparison of academic characteristics of these examinees across classes reveals some clear differences in manifest characteristics between groups.
The Performance of a Method for the Long‐term Equating of Mixed‐Format Assessment
Authors: Kamata Akihito , Tate Richard
Published: May 2005

The goal of this study was the development of a procedure to predict the equating error associated with the long‐term equating method of Tate (2003) for mixed‐format tests. An expression for the determination of the error of an equating based on multiple links using the error for the component links was derived and illustrated with simulated data. Expressions relating the equating error for single equating links to relevant factors like the equating design and the history of the examinee population ability distribution were determined based on computer simulation. Use of the resulting procedure for the selection of a long‐term equating design was illustrated.
The Effects of Artificial Selection on the Maize Genome
Authors: Wright Stephen I. , Bi Irie Vroh , Schroeder Steve G. , Yamasaki Masanori , Doebley John F. , McMullen Michael D. , Gaut Brandon S.
Published: May 2005

Domestication promotes rapid phenotypic evolution through artificial selection. We investigated the genetic history by which the wild grass teosinte (
Zea mays
ssp.
parviglumis
) was domesticated into modern maize (
Z. mays
ssp.
mays
). Analysis of single-nucleotide polymorphisms in 774 genes indicates that 2 to 4% of these genes experienced artificial selection. The remaining genes retain evidence of a population bottleneck associated with domestication. Candidate selected genes with putative function in plant growth are clustered near quantitative trait loci that contribute to phenotypic differences between maize and teosinte. If we assume that our sample of genes is representative, ∼1200 genes throughout the maize genome have been affected by artificial selection.
Solid-State Light Sources Getting Smart
Authors: Schubert E. Fred , Kim Jong Kyu
Published: May 2005

More than a century after the introduction of incandescent lighting and half a century after the introduction of fluorescent lighting, solid-state light sources are revolutionizing an increasing number of applications. Whereas the efficiency of conventional incandescent and fluorescent lights is limited by fundamental factors that cannot be overcome, the efficiency of solid-state sources is limited only by human creativity and imagination. The high efficiency of solid-state sources already provides energy savings and environmental benefits in a number of applications. However, solid-state sources also offer controllability of their spectral power distribution, spatial distribution, color temperature, temporal modulation, and polarization properties. Such “smart” light sources can adjust to specific environments and requirements, a property that could result in tremendous benefits in lighting, automobiles, transportation, communication, imaging, agriculture, and medicine.