bluuebunny/crossref_metadata_2025 huggingface dataset:
The Arabidopsis AtPNG1 gene encodes a peptide: N‐glycanase
Authors: Diepold Andreas , Li Guangtao , Lennarz William J. , Nürnberger Thorsten , Brunner Frédéric
Published: July 2007

Deglycosylation of misfolded proteins by the endoplasmic reticulum‐associated degradation (ERAD) pathway is catalyzed by peptide:N‐glycanases (PNGases) that are highly conserved among mammals and yeast. The catalytic mechanism of PNGases employs a catalytic triad consisting of Cys, His and Asp residues, which is shared by other enzyme families such as cysteine proteases and protein cross‐linking transglutaminases (TGases). In contrast to the yeast and mammalian systems, very little is known about ERAD in plants and the enzymes responsible for proper clearance of misfolded plant proteins. We have used a computer‐based modeling approach to identify an Arabidopsis thaliana PNGase (AtPNG1). AtPNG1 is encoded by a single‐copy gene and displays high structural homology with known PNGases. Importantly, heterologous expression of AtPNG1 restored N‐glycanase activity in a PNGase‐deficient Saccharomyces cerevisiae mutant. The AtPNG1 gene is uniformly and constitutively expressed at low levels throughout all developmental stages of the plant, and its expression does not appear to be subject to substantial regulation by external stimuli. Recently, recombinant AtPNG1 produced in Escherichia coli was reported to display TGase activity (Della Mea et al., Plant Physiol. 135, 2046–54, 2004). However, inactivation of the AtPNG1 gene did not result in decreased TGase activity in the mutant plant, and recombinant AtPNG1 produced in S. cerevisiae exhibited only residual TGase activity. We propose that the AtPNG1 gene encodes a bona fide peptide:N‐glycanase that contributes to ERAD‐related protein quality control in plants.
Low Temperature Effects during Seed Filling on Chickpea Genotypes (Cicer arietinum L.): Probing Mechanisms affecting Seed Reserves and Yield
Authors: Nayyar H. , Kaur G. , Kumar S. , Upadhyaya H. D.
Published: July 2007

Chickpea is sensitive to cold conditions (<15 °C), particularly at its reproductive phase and consequently it experiences significant decrease in the seed yield. The information about the effects of cold stress on chickpea during the seed filling phase is lacking. Moreover, the underlying metabolic reasons associated with the low temperature injury are largely unknown in the crop. Hence, the present study was undertaken with the objectives: (i) to find out the possible mechanisms leading to low temperature damage during the seed filling and (ii) to investigate the relative response of the microcarpa (Desi) and the macrocarpa (Kabuli) chickpea types along with elucidation of the possible mechanisms governing the differential cold sensitivity at this stage. At the time of initiation of the seed filling (pod size ∼1 cm), a set of plants growing under warm conditions of the glasshouse (temperature: 17/28 ± 2 °C as average night and day temperature) was subjected to cold conditions of the field (2.3/11.7 ± 2 °C as average night and day temperature), while another set was maintained under warm conditions (control). The chilling conditions resulted in the increase in electrolyte leakage, the loss of chlorophyll, the decrease in sucrose content and the reduction in water status in leaves, which occurred to a greater extent in the macrocarpa type than in the microcarpa type. The total plant weight decreased to the same level in both the chickpea types, whereas the rate and duration of the seed filling, seed size, seed weight, pods per plant and harvest index decreased greatly in the macrocarpa type. The stressed seeds of both the chickpea types experienced marked reduction in the accumulation of starch, proteins, fats, crude fibre, protein fractions (albumins, globulins, prolamins and glutelins) with a larger decrease in the macrocarpa type. The accumulation of sucrose and the activity levels of the enzymes like starch synthase, sucrose synthase and invertase decreased significantly in the seeds because of the chilling, indicating impairment in sucrose import. Minerals such as calcium, phosphorous and iron as well as several amino acids (phenylalanine, tyrosine, threonine, tryptophan, valine and histidine) were lowered significantly in the stressed seeds. These components were limited to a higher extent in the macrocarpa type indicating higher cold sensitivity of this type.
Effects of Cadmium on Carbon and Nitrogen Assimilation in Shoots of Mungbean [Vigna radiata (L.) Wilczek] Seedlings
Authors: Wahid A. , Ghani A. , Ali I. , Ashraf M. Y.
Published: July 2007

Increased cadmium (Cd) uptake from contaminated soils damages plant metabolism. The purpose of this study was to determine Cd‐induced time‐related changes in some shoot growth and physiological attributes, and their interrelationships in Cd‐tolerant (NM‐98) and sensitive (NM‐28) mungbean varieties. Shoot Cd and leaf chlorosis increased with a concomitant reduction in shoot dry weight, leaf area, relative growth rate (RGR), net assimilation rate (NAR) and relative leaf expansion rate. Reduction in transpiration rate (E) and stomatal conductance (gs) and increase in substomatal CO2 level (Ci), indicated that Cd reduced net photosynthesis (Pn) by reducing CO2 fixation by Rubisco, albeit these changes were less pronounced in NM‐98. A positive correlation of chlorosis with shoot Cd, and negative relationships of chlorosis and shoot Cd with Pn revealed that Cd damages the photosynthetic apparatus in mungbean. Time course decrease in in vivo nitrate reductase activity (NRA) and an increase in soluble nitrate in NM‐28 revealed that Cd markedly hampers nitrogen assimilation. Positive correlations of RGR and NAR with Pn and NRA and negative ones with chlorosis, shoot dry weight, shoot Cd and Ci in NM‐98 suggested that mungbean sensitivity to Cd is due to perturbed C and N assimilation.
Influence of Growth Stage on Fusarium Head Blight and Deoxynivalenol Production in Wheat
Authors: Del Ponte E. M. , Fernandes J. M. C. , Bergstrom G. C.
Published: July 2007

Fusarium head blight is a major concern for wheat production worldwide. The fungi that cause the disease may infect head tissues from flowering to late stages of kernel development, but a better understanding of the influence of the time of infection on grain weight reduction and mycotoxin accumulation resulting from the infection process is needed. We investigated the influence of wheat reproductive stage at the time of inoculation on disease and grain quality parameters, especially production of deoxynivalenol (DON) in mature grains. Heads of Norm wheat were spray inoculated with a macroconidial suspension of a DON‐producing isolate of Fusarium graminearum at each of six reproductive stages from flowering to hard dough. Plants were incubated in a mist chamber for 48 h and then moved to the greenhouse until maturity. Norm wheat was susceptible at all stages inoculated but the highest grain weight reduction and DON accumulation occurred in plants inoculated past flowering to late milk stages. However, high incidences of kernel infection and significant levels of DON accumulation resulted from inoculations as late as the hard dough stage, even though there was no corresponding reduction in grain weight compared to non‐inoculated plants. The occurrence of commercially significant levels of DON in plump, high‐yielding wheat may result from infections that occur during favourable environments well after the flowering stages. Late infection and DON production should therefore be a future research focus for wheat breeding and integrated management of FHB and an important consideration for grading systems that employ the presence of visibly damaged kernels as a means of estimating DON content of wheat.
In vitro and ex vitro Selection of Potato Plantlets for Resistance to Early Blight
Authors: Rodríguez N. V. , Kowalski B. , Rodríguez L. G. , Caraballoso I. B. , Suárez M. A. , Pérez P. O. , Quintana C. R. , González N. , Ramos R. Q.
Published: July 2007

Reaction to the culture filtrate of Alternaria solani (Sorauer) was used as an indicator in an in vitro screening test to select lines with decreased field susceptibility to early blight from a population of 1000 putative mutants. Plantlets of cv. ‘Desirée derived from irradiated callus of potato were inoculated in vitro with a culture filtrate of A. solani (Sorauer). Of the 45 lines selected and subsequently evaluated under conditions of natural infection in the greenhouse six showed lesser degrees of early blight infection than the cv. Desirée control. The six lines selected in the greenhouse retained lower degrees of infection during 2 years of field trials.
J‐integral determination in riveted beams of a structural old steel by estimation methods*
Authors: MORENO J. , VALIENTE A.
Published: July 2007

This work deals with the application of the J‐integral estimation method to cracked riveted beams of old puddle iron. The ductility of some of these materials makes it necessary to use elasto‐plastic fracture criteria to assess damage tolerance. This requires a high computational effort because it involves the determination of the J‐integral in beams with plates and angles that interact by means of redundant forces dependent on crack size. The J‐integral estimation method proposed by the Electric Power Research Institute could reduce this effort provided it were shown to be valid for this type of beam. This work contributes to this end by comparing the J‐integral values resultant from the estimation method and a complete finite element modelling of a riveted beam consisting of two angles and a cracked plate made of actual puddle iron from a road bridge more than a century old but still in service. A number of samples removed from the bridge showed that this material failed in a ductile manner when it was fracture tested with fatigue precracked compact specimens, even at temperatures as low as −20 °C. The two types of J‐integral values found are in good agreement over the ranges of load and crack size explored.
Hypothermia treatment potentiates ERK1/2 activation after traumatic brain injury
Authors: Atkins Coleen M. , Oliva Anthony A. , Alonso Ofelia F. , Chen Shaoyi , Bramlett Helen M. , Hu Bing‐Ren , Dietrich W. Dalton
Published: July 2007

Traumatic brain injury (TBI) results in significant hippocampal pathology and hippocampal‐dependent memory loss, both of which are alleviated by hypothermia treatment. To elucidate the molecular mechanisms regulated by hypothermia after TBI, rats underwent moderate parasagittal fluid‐percussion brain injury. Brain temperature was maintained at normothermic or hypothermic temperatures for 30 min prior and up to 4 h after TBI. The ipsilateral hippocampus was assayed with Western blotting. We found that hypothermia potentiated extracellular signal‐regulated kinase 1/2 (ERK1/2) activation and its downstream effectors, p90 ribosomal S6 kinase (p90RSK) and the transcription factor cAMP response element‐binding protein. Phosphorylation of another p90RSK substrate, Bad, also increased with hypothermia after TBI. ERK1/2 regulates mRNA translation through phosphorylation of mitogen‐activated protein kinase‐interacting kinase 1 (Mnk1) and the translation factor eukaryotic initiation factor 4E (eIF4E). Hypothermia also potentiated the phosphorylation of both Mnk1 and eIF4E. Augmentation of ERK1/2 activation and its downstream signalling components may be one molecular mechanism that hypothermia treatment elicits to improve functional outcome after TBI.
Presynaptic protein distribution and odour mapping in glomeruli of the olfactory bulb of Xenopus laevis tadpoles
Authors: Manzini Ivan , Heermann Stephan , Czesnik Dirk , Brase Christoph , Schild Detlev , Rössler Wolfgang
Published: July 2007

The sensory input layer in the olfactory bulb (OB) is typically organized into spheroidal aggregates of dense neuropil called glomeruli. This characteristic compartmentalization of the synaptic neuropil is a typical feature of primary olfactory centres in vertebrates and most advanced invertebrates. In the present work we mapped the location of presynaptic sites in glomeruli across the OB using antibodies to presynaptic vesicle proteins and presynaptic membrane proteins in combination with confocal microscopy. In addition the responses of glomeruli upon mucosal application of amino acid‐odorants and forskolin were monitored using functional calcium imaging. We first describe the spatial distribution of glomeruli across the main olfactory bulb (MOB) in premetamorphic Xenopus laevis. Second, we show that the heterogeneous organization of glomeruli along the dorsoventral and mediolateral axes of the MOB is associated with a differential distribution of synaptic vesicle proteins. While antibodies to synaptophysin, syntaxin and SNAP‐25 uniformly labelled glomeruli in the whole MOB, intense synaptotagmin staining was present only in glomeruli in the lateral, and to a lesser extent in the intermediate, part of the OB. Interestingly, amino acid‐responsive glomeruli were always located in the lateral part of the OB, and glomeruli activated by mucosal forskolin application were exclusively located in the medial part of the OB. This correlation between odour mapping and presynaptic protein distribution is an additional hint on the existence of different subsystems within the main olfactory system in larval Xenopus laevis.
Sphingosylphosphocholine effects on cultured astrocytes reveal mechanisms potentially involved in neurotoxicity in Niemann‐Pick type A disease
Authors: Chiulli Nino , Codazzi Franca , Di Cesare Alessandra , Gravaghi Claudia , Zacchetti Daniele , Grohovaz Fabio
Published: July 2007

Niemann‐Pick type A is a disease characterized by the absence of a functional SMPD1 (acidic sphingomyelinase) gene and the abnormal accumulation of sphingomyelin. Under these conditions, also sphingosylphosphocholine (SPC, a sphingomyelin metabolite) accumulates in various tissues, including the brain, where it might act as a toxic stimulus, contributing to the appearance of the neurological symptoms. We studied the effects of SPC on astrocytic and neuronal cultures from rat. In particular, we investigated the possibility that SPC acts on astrocytes and that this represents the first step leading to neurodegeneration. Our results show that acute administration of SPC to astrocytes in culture promotes Ca2+ responses and a release of glutamate that, in turn, leads to cytosolic [Ca2+] elevation in neurons. We also show that chronic stimulation by SPC leads astrocytes to proliferate, but can also change their phenotype towards an activated state that might contribute to the inflammatory responses. Interestingly, upon acute SPC stimulation, activated astrocytes release more glutamate. In conclusion, we show that both chronic and acute exposure to SPC can constitute harmful signals that may have a role in the sequence of events leading to neurodegeneration.
Increase of serum C‐reactive protein is an early indicator of subsequent symptomatic anastomotic leakage after anterior resection
Authors: Matthiessen P. , Henriksson M. , Hallböök O. , Grunditz E. , Norén B. , Arbman G.
Published: July 2007

Objective  This prospective study investigated the factors which might indicate anastomotic leakage after low anterior resection.

Method  Thirty‐three patients who underwent anterior resection for rectal carcinoma (n = 32) and severe dysplasia (n = 1), were monitored daily by serum C‐reactive protein (CRP) and white blood cell count (WBC) estimations until discharge from hospital. Computed tomography (CT) scans were performed on postoperative days 2 and 7 and the amount of presacral fluid collection was assessed. All patients had a pelvic drain and the volume of drainage was measured daily.

Results  The level of the anastomosis was at a median 5 cm (3–12 cm) above the anal verge. There was no 30‐day mortality. Nine (27.2%) of the 33 patients developed a symptomatic anastomotic leakage which was diagnosed at a median of 8 days (range 4–14) postoperatively. The serum CRP was increased in patients who leaked from postoperative day 2 onwards (P = 0.004 on day 2; P < 0.001 on day 3–8). The WBC was decreased in preoperatively irradiated patients on days 1–5 (P ≤ 0.021), with no difference seen between patients with or without leakage. Patients with leakage had a larger presacral fluid collection on CT on day 7 (median 76 ml vs 52 ml; P = 0.016) and a larger increase in the fluid collection between the first and the second CT examinations (28 ml vs 3 ml; P = 0.046).

Conclusion  An early rise in serum CRP was a strong indicator of leakage. Monitoring of CRP for possible early detection of symptomatic anastomotic leakage is recommended.
MANAGEMENT BUYOUTS, SUPERVISION AND EMPLOYEE DISCRETION
Authors: Amess Kevin , Brown Sarah , Thompson Steve
Published: July 2007

Using a matched sample of 1959 firms and 27,263 employees from the UK Workplace Employee Relations Survey, we examine the effects of the management buyout (MBO) organizational form on employee discretion and supervision. Our findings suggest that for MBO firms, supervision is lower where there is a higher proportion of craft and skilled service workers but is not lower for other occupational groups. Using random effects ordered probit analysis, we find that employees' discretion over their work practices is higher in MBO firms; and that the probability of higher discretion is greater where there is a higher proportion of craft and skilled service employees. Our findings are consistent with: (i) MBOs reducing hierarchical tiers and the number of supervisory staff, which increase employees' span of control and their discretion; and (ii) organizational change via an MBO being ‘skill biased’ in favour of craft and skilled service employees.
OUTPUT AND INFLATION IN MODELS OF THE BUSINESS CYCLE WITH NOMINAL RIGIDITIES: FURTHER COUNTERFACTUAL IMPLICATIONS
Authors: Páez‐Farrell Juan
Published: July 2007

This paper examines the relationship between cyclical output and inflation in models commonly used for monetary policy analysis. This includes models that incorporate the New Keynesian, Fuhrer–Moore and backward‐looking Phillips curves. The main finding is that these models imply a strong negative relationship between inflation and output, a result that is at odds with the data. The fact that New Keynesian models yield counterfactual implications is not new; the novelty of the paper lies in the fact that the finding extends to the other variants, such as the backward‐looking Phillips Curve, which have been put forward as displaying superior dynamics.
INEQUALITY AND GROWTH: FROM MICRO THEORY TO MACRO EMPIRICS
Authors: Gobbin Niko , Rayp Glenn , Van de gaer Dirk
Published: July 2007

We show that the way individual income data should be aggregated into an index of inequality in order to explain countries' growth performance is theory specific. A simulation set‐up shows that the use of a wrong measure might obscure the inequality–growth relationship and that the relative performance of different measures of inequality can be informative about the channel through which inequality influences economic growth.
OCCUPATIONAL PENSIONS, WAGES, AND JOB MOBILITY IN GERMANY
Authors: Rabe Birgitta
Published: July 2007

Pension‐covered workers in Germany are three times less likely to change jobs than workers not covered by an occupational pension scheme. This paper examines the effects of occupational pension coverage and pension portability loss on voluntary job changes using a sample selection model with endogenous switching. The model estimates, derived from western German panel data for 1985–1998, indicate that occupational pension coverage reduces worker mobility by imposing a capital loss on those leaving their job before retirement age. Moreover, pension‐covered workers receive a higher compensation, which discourages mobility. Making pensions portable increases mobility, but from a low initial level.
KEEPING UP WITH THE JONESES, GROWTH, AND DISTRIBUTION
Authors: Tsoukis Chris
Published: July 2007

A recent class of models on ‘keeping up with the Joneses’ suggests that comparison with the consumption of other individuals affects individual utility. This paper nests three variants of the ‘Joneses’ effect into an otherwise standard growth model. Under some conditions, growth and distribution are jointly determined, presenting thus a unification of the relevant theories. These variants are however not equivalent in terms of their effects on growth and distribution. It is also shown that, at least if comparisons‐in‐mean predominate, rises in the mean skills level and in the exogenous skills variance increase both growth and inequality with ambiguous effects on aggregate welfare.
International Comparisons of Banking Efficiency
Authors: Berger Allen N.
Published: August 2007

The banking industry around the globe has been transformed in recent years by unprecedented consolidation and cross‐border activities. However, international consolidation has been considerably less than might have been expected in developed nations—such as long‐term members of the EU—where barriers to entry have been significantly lowered. In contrast, foreign‐owned banks have generally achieved much higher penetration in developing nations. We investigate the extent to which these differences may be related to bank efficiency concerns by reviewing and critiquing over 100 studies that compare bank efficiencies across nations. The studies are in three distinct categories: (1) comparisons of bank efficiencies in different nations based on the use of a common efficient frontier, (2) comparisons of bank efficiencies in different nations using nation‐specific frontiers, and (3) comparisons of efficiencies of foreign‐owned versus domestically owned banks within the same nation using the same nation‐specific frontier. The research—particularly the findings in the third category—is generally consistent with the hypothesis that efficiency differences help to explain the consolidation patterns. The efficiency disadvantages of foreign‐owned banks relative to domestically owned banks tend to outweigh the efficiency advantages in developed nations on average, and this situation is generally reversed in developing nations, with notable exceptions to both findings. We also stress the need for further research in this area.
The time course of building discourse coherence in schizophrenia: An ERP investigation
Authors: Ditman Tali , Kuperberg Gina R.
Published: July 2007

Impairments in the buildup and use of context may lead to disorders of thought and language in schizophrenia. To test this hypothesis, event‐related potentials (ERPs) were measured while patients and healthy controls read sentences that were highly causally related, intermediately related, or unrelated to preceding contexts. Although patients were slower than controls, both groups used the discourse context similarly as evidenced by similar reaction time patterns across conditions. Neurally however, different patterns emerged between patients and controls: within the N400 time window, patients failed to modulate their neural responses across conditions. This failure to differentiate between conditions was specifically correlated with positive thought disorder. Results suggest that schizophrenia patients, particularly those with positive thought disorder, fail to make immediate use of discourse context to build up semantic coherence in the brain.
It's worse than you thought: The feedback negativity and violations of reward prediction in gambling tasks
Authors: Hajcak Greg , Moser Jason S. , Holroyd Clay B. , Simons Robert F.
Published: July 2007

The reinforcement learning theory suggests that the feedback negativity should be larger when feedback is unexpected. Two recent studies found, however, that the feedback negativity was unaffected by outcome probability. To further examine this issue, participants in the present studies made reward predictions on each trial of a gambling task where objective reward probability was indicated by a cue. In Study 1, participants made reward predictions following the cue, but prior to their gambling choice; in Study 2, predictions were made following their gambling choice. Predicted and unpredicted outcomes were associated with equivalent feedback negativities in Study 1. In Study 2, however, the feedback negativity was larger for unpredicted outcomes. These data suggest that the magnitude of the feedback negativity is sensitive to violations of reward prediction, but that this effect may depend on the close coupling of prediction and outcome.
A way of seeing study abroad: narratives from nurse education
Authors: Greatrex‐White Sheila
Published: July 2007

This paper reports on the findings of a phenomenological study of nursing students studying abroad. The literature shows that study abroad has long been part of liberal educational approaches dating back to medieval times. Yet it is only recently that undergraduate nursing students have been allowed to study abroad as part of their formal programme. The research conducted was informed by the philosophical hermeneutic phenomenology of Martin Heidegger and was designed to answer the question: ‘How is study abroad manifest in the experience of nursing students?’ Data were collected through the use of unstructured diaries of 26 nursing students studying at two universities in the United Kingdom. Analysis uncovered six structures or ‘ways for study abroad to be’: leaving behind, escape, foreigner, learning, self‐discovery and risk. The main focus of this paper is ‘leaving behind’; the selection of this structure reflects its general interest and predominance in data analysis. Interpretation of the structure suggests that study abroad might offer an opportunity to militate against the limiting effects of personal and professional socialization processes. Here, socialization is viewed as a state of becoming and study abroad for some nursing students is a facet of this state of becoming. Finally, it is argued that study abroad is deserving of much greater attention in nurse education and beyond. For example, the concepts of global communities and a global economy necessitate the need for employees in the future to have wider experiences and understanding of different cultures and understanding the experience of study abroad is one possible contribution to this. Thus, it is believed that this study makes a valuable contribution to teaching and learning discourses, specifically nurse education and also in wider educational arenas.
Elevated Homocysteine Levels in Patients with Slow Coronary Flow: Relationship with Helicobacter pylori Infection
Authors: Evrengul Harun , Tanriverdi Halil , Kuru Omur , Enli Yasar , Yuksel Dogangun , Kilic Ayhan , Kaftan Asuman , Kirac Suna , Kilic Mustafa
Published: July 2007

Background and objective:  Elevation of plasma homocysteine (Hcy) level has been implicated in the pathogenesis of slow coronary flow (SCF) as it can severely disturb vascular endothelial function. Helicobacter pylori chronically infect the human stomach and causes malabsorption of vitamin B12 and folate in food, leading ultimately to an increase in circulating Hcy levels.

Methods:  Forty‐three patients with angiographically proven SCF (group I) were enrolled in this study; 43 cases with normal coronary flow pattern (group II) served as controls. Fasting plasma levels of Hcy, vitamin B12, and folate were measured in all subjects. Presence of H. pylori infection was defined as positive 14 C urea breath test. Coronary flow patterns for each major epicardial coronary artery were determined with the Thrombolysis in Myocardial Infarction (TIMI) frame count method.

Results:  Mean TIMI frame count was 46.3 ± 8.7 in group I and 24.3 ± 2.9 in Group II (p = .0001). Vitamin B12 levels were similar, whereas folate levels were dramatically reduced in group I compared to group II (13.2 ± 4.3 vs. 17.1 ± 5.2, p = .0001). Plasma Hcy levels were significantly higher in group I compared to group II (13.4 ± 5.6 vs. 7.9 ± 2.5, p = .0001) as was the prevalence of H. pylori infection (90.7% in group I vs. 58.1% in group II, p = .001). Hcy levels were elevated (11.7 ± 5.3 vs. 7.5 ± 2.7, p = .0001) and folate levels were reduced (13.9 ± 4.7 vs. 18.6 ± 4.9, p = .0001) in patients with H. pylori infection, while vitamin B12 levels were similar in patients with and without H. pylori infection. Correlation analysis revealed a significant negative correlation between plasma folate and Hcy levels and also between folate levels and mean TIMI frame counts (r = –.33, p = .002 vs. r = –.33, p = .003). Moreover, there was a significant positive correlation between plasma Hcy levels and mean TIMI frame counts (r = .66, p = .0001). In addition, the folate level was the only significant determinant of the variance of Hcy in multiple regression analysis (r = –.21, p = .03).

Conclusion:  Our data showed that plasma folate levels were decreased and plasma Hcy levels were increased in patients with SCF compared to controls. Also, the prevalence of H. pylori infection was increased in patients with SCF. These findings suggest that elevated levels of plasma Hcy, possibly caused by H. pylori infection, and/or a possible disturbance in its metabolism may play a role in the pathogenesis of SCF.
Helicobacter pylori Colonization in the First 3 Years of Life in Japanese Children
Authors: Okuda Masumi , Miyashiro Eikichi , Booka Mina , Tsuji Tomomi , Nakazawa Teruko
Published: July 2007

Background:  Acquisition of Helicobacter pylori infection occurs in early childhood, but the exact time of the acquisition and dynamics of infection are not clear. The aim of this study was to estimate the time of acquisition of H. pylori colonization in infants.

Subjects and methods:  This prospective follow‐up study included 237 infants born in Wakayama Rosai Hospital from February, 2001 to April, 2002. Stool samples were collected at indicated ages, and H. pylori antigens were determined by a stool antigen test, HpSA.

Results:  One‐hundred and eight infants among initially enrolled 237 children have been followed up until 24 months. Among these, 16 infants turned to be HpSA positive within 12 months, but only four remained positive by the consecutive tests with optical density values of more than 0.7. They were assumed persistent positives. The rest 12 infants reverted to be negative by the consecutive tests and were assumed transient or false‐positives. The optical density values of HpSA in the transient cases were exclusively less than 0.35.

Conclusions:  The consecutive follow up of HpSA, but not the one‐point test, might be useful to diagnose persistent colonization of H. pylori in young infants, and some infants seemed to acquire H. pylori infection in the first year of life. These results should be taken into account for prevention and treatment strategies for H. pylori infection in infants.
A Review of the Postulated Mechanisms Concerning the Association of Helicobacter pylori with Ischemic Heart Disease
Authors: Manolakis Anastassios , Kapsoritakis Andreas N. , Potamianos Spiros P.
Published: July 2007

Since its discovery, Helicobacter pylori has been implicated in the pathogenesis of several diseases, both digestive and extradigestive. Interestingly, the majority of the extradigestive‐related literature is focused on two vascular manifestations: stroke and ischemic heart disease. Potential mechanisms for the establishment of a H. pylori‐induced ischemic heart disease have been proposed with regard to chronic inflammation, molecular mimicry, oxidative modifications, endothelial dysfunction, direct effect of the microorganism on atherosclerotic plaques as well as changes regarding traditional or novel risk factors for ischemic heart disease or even platelet‐H. pylori interactions. A positive link between H. pylori infection and ischemic heart disease has been suggested by a series of studies focusing on epidemiologic evidence, dyslipidemic alterations, upregulation of inflammatory markers or homocysteine levels, induction of hypercoagulability, oxidation of low‐density lipoprotein, causation of impaired endothelial function, detection of H. pylori DNA in atherosclerotic plaques, and participation of certain antigens and antibodies in a cross‐reactivity model. There are studies, however, which investigated the relationship between H. pylori and ischemic heart disease with regard to the same parameters and failed to confirm the suggested positive association. Further studies in the direction of interaction between H. pylori and the host's genotype as well as a quest for evidence towards novel risk factors for ischemic heart disease such as oxidative stress, vascular remodeling, vascular calcification, or vasomotor activity, may reveal a field of great interest, thus contributing to the determination of new potential mechanisms.
The Role of Therapeutic Inertia and the Use of Fixed‐Dose Combination Therapy in the Management of Hypertension
Authors: Basile Jan , Black Henry R. , Flack John M. , Izzo Joseph L.
Published: July 2007

On April 9, 2007, a panel discussion was held to discuss the role of therapeutic inertia and the value of using fixed‐dose combination therapy in the management of hypertension. The panel was moderated by Jan Basile, MD, Professor of Medicine, Ralph H. Johnson VA Medical Center, Charleston, SC. Discussants included Henry R. Black, MD, Clinical Professor Internal Medicine, New York University School of Medicine, New York, NY, John A. Flack, MD, MPH, Professor and Interim Chair and Chief, Division of Translational Research and Epidemiology, Department of Medicine, Wayne State University, Detroit, MI, and Joseph L. Izzo, Professor and Vice Chair, State University of New York at Buffalo, Buffalo, NY. This expert panel discussion was supported by Novartis and each author received an honorarium from Novartis for time and effort spent participating in the discussion and reviewing the transcript for important intellectual content prior to publication. The authors maintained full control of the discussion and the resulting content of this article.
Correlation of Tricuspid Annular Velocities With Invasive Hemodynamics in Pulmonary Hypertension
Authors: Rajagopalan Navin , Saxena Neil , Simon Marc A. , Edelman Kathy , Mathier Michael A. , López‐Candales Angel
Published: July 2007

The authors performed tissue Doppler imaging of the tricuspid annulus in patients with pulmonary hypertension to assess its correlation with invasive indices of right ventricular function. The study population consisted of 32 patients with suspected pulmonary hypertension who underwent pulsed tissue Doppler imaging of the tricuspid annulus and right heart catheterization. Peak systolic (Sa), early diastolic (Ea), and late diastolic (Aa) velocities of the lateral tricuspid annulus were measured and correlated with hemodynamic variables. Peak Sa demonstrated excellent correlation with hemodynamic variables, including cardiac index (r=0.78; P<.001), pulmonary vascular resistance (r=−0.79; P<.001), and transpulmonary gradient (r=−0.72; P<.001). Peak Sa <10 cm/s predicted cardiac index <2.0 L/min/m2 with 89% sensitivity and 87% specificity. In conclusion, tissue Doppler imaging of the tricuspid annulus is a complementary method to assess right ventricular function in pulmonary hypertensive patients.
Treatment of Ventricular Dysrhythmias and Sudden Cardiac Death: A Guideline‐Based Approach for Patients With Chronic Left Ventricular Dysfunction
Authors: Hasan Ayesha , Yancy Clyde W.
Published: July 2007

With the rise in the use of device therapy implants, we are better identifying appropriate chronic heart failure patients for primary implantable defibrillator therapy who are at risk of ventricular arrhythmia. As our knowledge expands, however, controversial issues emerge. Guidelines have been endorsed by the major international societies, such as the American College of Cardiology (ACC), the American Heart Association (AHA), and the European Society of Cardiology. In view of certain variances in recommendations and new data, a recent joint guideline statement has been issued from these 3 societies regarding management of ventricular arrhythmia and preventing sudden cardiac death in patients with left ventricular dysfunction and heart failure. In this review, the recent joint statement is compared with those from the Heart Failure Society of America (Heart Failure Practice Guidelines 2006) and ACC/AHA (Heart Failure Guidelines 2005), with a special emphasis on new expanded criteria for primary prevention in both ischemic and nonischemic heart disease. In addition, the authors review current guidelines for electrophysiology testing in chronic left ventricular dysfunction and the emerging role of microvolt T‐wave alternans as a means of risk stratification.
Idiopathic Generalized Epilepsy with Absences: Syndrome Classification
Authors: Valentin Antonio , Hindocha Neeti , Osei‐Lah Abeena , Fisniku Leonora , McCormick David , Asherson Phillip , Moran Nicholas , Makoff Andrew , Nashef Lina
Published: July 2007

Summary

In a cohort of 275 Caucasians with a broad IGE phenotype, patients with absences were classified. Criteria of the 1989 Commission on Classification of the International League Against Epilepsy for Childhood Absence Epilepsy (CAE 1989 criteria) were compared with the stricter criteria of the ILAE Task Force for Classification and Terminology (CAE 2005 criteria). Among the 129 patients with absences without significant myoclonus, 50 had juvenite absence epilepsy 44 had CAE according to the CAE 1989 criteria and only 30 had CAE according to the CAE 2005 criteria. We found a significantly better outcome in patients considered as CAE by the CAE 2005 criteria, compared with those excluded. Strict criteria for classification of absence syndromes leave many patients unclassified. However, diagnostic criteria used to classify CAE patients have prognostic significance. We propose that patients are classified as having benign CAE or as having CAE with the adverse prognostic factors indicated.
Focal Increases in Perfusion and Decreases in Hemoglobin Oxygenation Precede Seizure Onset in Spontaneous Human Epilepsy
Authors: Zhao Mingrui , Suh Minah , Ma Hongtao , Perry Challon , Geneslaw Andrew , Schwartz Theodore H.
Published: July 2007

Summary

Purpose: Optical recording of intrinsic signals provides the highest combined spatial and temporal resolution with broad spatial sampling for measuring cerebral blood volume (CBV) and hemoglobin oxygenation in cerebral cortex. Few opportunities arise to apply this laboratory method to record spontaneous seizures in unanesthetized human brain during neurosurgery. We report such a rare opportunity in a man with recurrent focal epilepsy arising from a cavernous malformation.

Methods: We recorded intrinsic optical signals (IOS) from human cortex intraoperatively during spontaneous seizures arising from brain surrounding a small cavernous malformation in an awake patient using only local anesthesia with simultaneous electrocorticography. The IOS was recorded at two wavelengths, one an isosbestic point for hemoglobin to measure CBV (570 nm) and the other at a wavelength more sensitive to deoxygenated hemoglobin (Hbr) (610 nm). A modified Beer‐Lambert calculation was used on two separate but similar seizures to approximate changes in Hbr, CBV as well as oxygenated hemoglobin (HbO2).

Results: Electrographically recorded seizures (n = 3) elicited a focal increase in both Hbr and CBV that lasted for the duration of the seizure, indicating that perfusion was inadequate to meet metabolic demand. Remarkably, these hemodynamic changes preceded the onset of the seizures by ∼20 s and occurred focally over the known location of the lesion and the seizure onsets.

Discussion: These findings demonstrate that the hemoglobin becomes deoxygenated in spite of large increase in CBV during spontaneous human focal seizures and that optically recorded hemodynamic events can be used both to predict and localize human focal epilepsy. Such data may someday be useful to assist in the presurgical evaluation of patients considered for epilepsy surgery and to predict the timing and location of seizure onsets.
MOLECULAR PHYLOGENY OF THE GREEN ALGAL ORDER PRASIOLALES (TREBOUXIOPHYCEAE, CHLOROPHYTA)1
Authors: Rindi Fabio , McIvor Lynne , Sherwood Alison R. , Friedl Thomas , Guiry Michael D. , Sheath Robert G.
Published: July 2007

The systematics of the Prasiolales was investigated by phylogenetic inference based on analyses of therbcL and 18S rRNA genes for representatives of all four genera currently attributed to this order (Prasiococcus,Prasiola,Prasiolopsis,Rosenvingiella), including all type species. TherbcL gene had higher sequence divergence than the 18S rRNA gene and was more useful for phylogenetic inference at the ranks of genus and species. In therbcL gene phylogeny, three main clades were observed, corresponding toPrasiola,Prasiolopsis, andRosenvingiella.Prasiococcuswas nested among species ofPrasiolaoccurring in subaerial and supralittoral habitats.Trichophilus welckeriWeber Bosse, a subaerial alga occurring in the fur of sloths in Amazonia, was closely related toPrasiolopsis ramosaVischer. The species ofPrasiolawere grouped into three well‐supported clades comprising (i) marine species, (ii) freshwater and terrestrial species with linear blades, and (iii) terrestrial species with rounded or fan‐shaped blades. Sequence divergence was unexpectedly low in the marine group, which included species with different morphologies. For the 18S rRNA gene, the phylogenetic analyses produced several clades observed for therbcL gene sequence analysis, but, due to very little sequence variation, it showed considerably lower resolution for inference at the species and genus levels. Due to the low support of some internal branches, the results of the analyses did not allow an unambiguous clarification of the origin and the early evolution of the Prasiolales.
AIRBORNE ALGAE: THEIR PRESENT STATUS AND RELEVANCE1
Authors: Sharma Naveen Kumar , Rai Ashwani Kumar , Singh Surendra , Brown Richard Malcolm
Published: July 2007

Ongoing climatic changes coupled with various natural processes and the outcomes of human activities are not only loading the atmosphere with diverse kinds of biological particles but also changing their prevalence and spatial distribution. Despite having considerable ecological and economic significance, including their possible impact on human health, airborne algae are the least‐studied organisms in both aerobiological and phycological studies. The present review has been written to bring together all available information, including a brief survey of the literature, the ecology of airborne algae, mechanisms involved in their aerosolization, the role of environmental factors in shaping the structure and composition of aero‐algal flora, and other significant information associated with airborne algae. This review provides information on methodological approaches and related problems, along with suggestions for areas of future research on airborne algae.
EFFECT OF NITROGEN STARVATION ON OPTICAL PROPERTIES, PIGMENTS, AND ARACHIDONIC ACID CONTENT OF THE UNICELLULAR GREEN ALGA PARIETOCHLORIS INCISA (TREBOUXIOPHYCEAE, CHLOROPHYTA)1
Authors: Merzlyak Mark N. , Chivkunova Olga B. , Gorelova Olga A. , Reshetnikova Irina V. , Solovchenko Alexei E. , Khozin‐Goldberg Inna , Cohen Zvi
Published: July 2007

Spectral properties of cell suspensions, individual cells, and extracts of the unicellular green alga Parietochloris incisa (Reisigl) Shin Watan. grown under low light were studied. Long‐term nitrogen (N) deprivation resulted in a decrease of chloroplast volume, appearance of numerous large cytoplasmic oil bodies, and the deposition of triacylglycerols with a high proportion of arachidonic acid. Chlorophylls a and b underwent a synchronous decline, whereas carotenoids (Car) showed a relative increase. Simultaneously, significant qualitative changes in the spectral properties of P. incisa individual cells, cell extracts, and cell suspensions were observed. To a large extent, the spectral changes observed in cell suspension could be attributed to a decrease in overall pigment content, leading to a gradual weakening of the so‐called package effect and accumulation of additional amounts of Car over chl, most probably, in oil bodies. Several optical characteristics of cell suspensions could serve as sensitive indicators of N‐deficiency in P. incisa. Furthermore, the absorption ratios, A476/A676 and A650/A676, showed close correlations with the Car‐to‐chl ratio and relative arachidonic acid (AA) content, respectively. The latter makes it possible to suggest that the increase in AA percentage in P. incisa proceeds in parallel with a decrease in cell chl content, accounting for the weakening of the package effect. N‐replenishment resulted in complete recovery of cell optical properties. The possible significance of the changes in cell ultrastructure, pigments, lipids, and optical properties is discussed with special reference to the ability of algae to adapt to and survive under conditions of long‐term nutrient deficiency.
THE CYANOBACTERIAL GENUS BRASILONEMA, GEN. NOV., A MOLECULAR AND PHENOTYPIC EVALUATION1
Authors: Fiore Marli Fátima , Sant’Anna Celia Leite , Azevedo Maria Teresa de Paiva , Komárek Jiři , Kaštovský Jan , Sulek Josef , Lorenzi And Adriana Sturion
Published: July 2007

Twelve populations of filamentous, heterocytous scytonematoid cyanobacteria from subaerophytic (mainly epiphytic) habitats in subtropical and tropical Brazil (São Paulo) were studied. The populations form a uniform cluster, which differs from the traditional scytonematoid genera genetically and by several indistinct, but typical morphological characters (fasciculation of filaments, rare false branching). Two strains were isolated in monospecific cultures. Molecular analyses were performed on these strains from natural populations taken from bromeliad leaves and iron water pipes. Because the results from 16S rRNA gene sequencing indicated the separate position of this cyanobacterium at the generic level, a new genus, Brasilonema, is proposed with the type species Brasilonema bromeliae. The new genus is described using combined molecular and cytomorphological criteria, in accordance with the nomenclatorial recommendations of both the Bacteriological Code and the Botanical Code of Nomenclature (cf. Oren 2004). The ultrastructure of the type species was studied, and vacuole‐like structures in the cells were explained. The genus Brasilonema is commonly distributed, particularly in subaerophytic habitats from southeastern Brazil. The type species (B. bromeliae) has a rather curious ecology, living epiphytically (in phytothelmes) inside the vase‐shaped leaf rosettes of bromeliads.
Learning Disabilities in Taiwan: A Case of Cultural Constraints on the Education of Students with Disabilities
Authors: Tzeng Shih–Jay
Published: July 2007

Learning disabilities (LD) has been recognized as a category of special education in Taiwanese law since 1984, and policies ensure educational services for children and youth who have LD. The official definition and identification criteria established in Taiwan's laws closely correspond with those of the United States, but practice differs, largely influenced by the people's cultural and linguistic background. I discuss these legal and cultural features as well as other matters (e.g., growth and change in professional literature on LD). Compared to economically developed countries such as the United States, the educators in Taiwan implement identification procedures, placement, and services at a lower cost. Contents of implementation are introduced in detail. The prevalence rate of LD has been very low (<1 percent). I examine culture– and/or society–specific reasons for low prevalence, such as Chinese orthography, regular teachers’ compliance with referral procedures, the education–first belief of parents, and problems with identification procedures.