bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biochemical analysis of a Ca2+‐dependent membrane–membrane interaction mediated by the sea urchin yolk granule protein, toposome
Authors: Hayley Michael , Perera Aruni , Robinson John J. 
Published: July 2006

Toposome, a high molecular mass protein, is an abundant component of the yolk granule in the sea urchin egg and embryo. Toposome is composed of a 160 kDa polypeptide that is proteolytically processed into smaller species of 120 and 90 kDa during embryonic development. The exact biological function of toposome during early development is unknown. In this study we have examined calcium binding to toposome and the effect of this binding on the secondary and tertiary structural characteristics of the purified protein. Initially, we used equilibrium dialysis to quantify calcium binding to toposome. Monophasic binding of up to 600 M of calcium per mole of protein was detected with an intrinsic dissociation constant (calcium) of 240 µm. Increasing concentrations of calcium resulted in an increase in alpha helical content from 3.0 to 22.0%, which occurred with an apparent dissociation constant (calcium) of 25 µm. In parallel experiments, toposome binding to liposomes required similar concentrations of calcium; an apparent dissociation constant (calcium) of 25 µm was recorded. Endogenous tryptophan fluorescence measurements, both in the presence and absence of liposomes, demonstrated that the tertiary structure is sensitive to increasing concentrations of calcium with an apparent dissociation constant (calcium) of 240 µm. Toposome‐driven, liposome aggregation assays revealed a similar calcium requirement. Collectively, these results define a two‐step model for calcium modulation of toposome structure and function.
New Zealand cataract and refractive surgery survey 2004
Authors: Elder Mark , Leaming David , Hoy Benjamin 
Published: July 2006

AbstractBackground:  This study examines the current practice and trends for cataract and refractive surgery in New Zealand.Methods:  A confidential postal questionnaire was sent to all consultant ophthalmologists practising in New Zealand in 2004. Most questions were identical to the 2000 New Zealand survey, and were also similar to the 2003 survey of the American Society of Cataract and Refraction Surgeons (ASCRS).Results:  From 97 surveys there was a 92% response rate. Of those surveyed, 70 were performing cataract surgery, 17 were performing refractive surgery, subtenons anaesthetic was used for cataract surgery in 60%, clear corneal or anterior limbal incision in 86%, one‐piece foldable intraocular lens in 65%. For refractive surgery, use of refractive lens surgery was recommended for high refractive errors. Advice to a 45‐year‐old +3.00 hypermetrope wanting refractive surgery was to have laser in situ keratomileusis (88%), laser epithelial keratomileusis (6%) or clear lens extraction (6%). Ninety‐four per cent of refractive surgeons in New Zealand used a wavefront analyser. Clear lens extraction was practised by 23 ophthalmologists, phakic intraocular lenses by 16 ophthalmologists.Discussion:  New Zealand cataract and refractive surgery practice remains comparable to that of the members of the ASCRS. As in previous comparisons, there is a relatively low use of topical anaesthetic (New Zealand 19%vs. USA 61%vs. UK [pilot study] 33.3%). This survey showed a high uptake of wavefront analysis in refractive surgery (New Zealand 94%vs. USA 45%).
Evaluation of the effects of hydrodissection with antimitotics using a rabbit model of Soemmering’s ring formation
Authors: Chew Jesse , Werner Liliana , Stevens Scott , Hunter Brian , Mamalis Nick 
Published: July 2006

AbstractBackground:  Regeneration/proliferation of lens material within the capsular bag still is the most frequent complication after cataract surgery. We aimed to evaluate the effects of hydrodissection with low doses of antimitotics on the overall regeneration/proliferation of lens material in rabbit eyes, using a model allowing the lens material to be confined to the equatorial region of the capsular bag, facilitating its quantification.Methods:  Twelve albino rabbits underwent bilateral phacoemulsification. Their eyes were randomized to receive 0.4 cc of balanced salt solution, 5‐fluorouracil (12.5 mg/mL) or mitomycin C (0.1 mg/mL) during hydrodissection. They were left aphakic, so the capsulorhexis would fuse with the posterior capsule postoperatively. After 4 weeks, killing/enucleation was performed. Regeneration/proliferation of lens material within the equatorial capsular bag (Soemmering’s ring) was graded from the Miyake–Apple view (0–4). Its area was also calculated (µm2) from direct measurements performed on histological sections.Results:  The capsulorhexis margin fused with the peripheral posterior capsule, so the central posterior capsule remained clear. There was no significant difference among the groups (Kruskal–Wallis test) regarding Soemmering’s ring gross grading (P = 0.511), number of lens epithelial cell layers lining the inner surface of the capsular bag (P = 0.310) and Soemmering’s ring microscopic cross‐sectional area (P = 0.638).Conclusions:  The effect of different solutions on after‐cataract should be assessed in terms of overall regeneration/proliferation of lens material within the capsular bag, in addition to posterior capsule opacification. When administered in low doses during hydrodissection, 5‐fluorouracil and mitomycin C did not show a significant inhibitory effect on after‐cataract formation in rabbit eyes.
Microcirculation at optic disc rim is correlated with visual field defects in cases of anterior ischaemic optic neuropathy
Authors: Yokoyama Shinsuke , Kimura Itaru , Ohde Hisao , Shinoda Kei , Mashima Yukihiko 
Published: July 2006

AbstractWe report two cases of anterior ischaemic optic neuropathy in whom tissue blood flow at the disc rim was correlated with the visual field defect. Tissue blood flow of each eye was evaluated with Heidelberg retina flowmeter. Both cases experienced acute visual loss and an altitudinal hemianopsia associated with optic disc oedema in the affected eye. In each case, the tissue blood flow at the affected (upper or lower half) disc rim corresponding to visual field deficit was reduced compared with that at the opposite‐sided half disc rim in the affected eye and with the corresponding area in the fellow eye. The reduction of blood flow in the affected half disc rim associated with the visual field defect demonstrated that retina flowmetry can detect differences in tissue blood flow between superior and inferior sectional disc rim areas as well as between eyes non‐invasively.
Concordant bilateral Duane’s Retraction Syndrome (type 1) in female monozygotic twins
Authors: Dirani Mohamed , Chamberlain Matthew , Garoufalis Pam , Chen Christine , Guymer Robyn H , Baird Paul N 
Published: July 2006

AbstractWe report a single case study of concordant bilateral Duane’s Retraction Syndrome (DRS) (type 1) in female monozygotic (MZ) twins aged 47 years. The twin pair were recruited through the Australian Twin Registry as part of a twin study on myopia. This twin pair were full term and had a similar birth weight: 2.27 kg and 1.81 kg in twin 1 and twin 2, respectively. There was no report of any other childhood medical conditions in either twin. Both twins had an equal amount of restriction in right and left abduction. Narrowing of the palpebral fissures and globe retraction in right and left adduction was also observed in both twins. To our knowledge this is the first case to report concordant bilateral DRS (type 1) in female MZ twins. The concordance for the presence of DRS and associated clinical signs observed in this MZ twin pair supports a genetic origin to DRS.
Characterization of fretting fatigue in self‐piercing riveted aluminium alloy sheets
Authors: HAN L. , CHRYSANTHOU A. , YOUNG K. W. , O'SULLIVAN J. M. 
Published: July 2006

ABSTRACTA study was conducted to characterize fretting fatigue in self‐piercing riveted single‐lap joints of aluminium alloy 5754 sheets. The experimental results showed that fretting occurred at three different positions in the joint. It was established that fretting led to surface work‐hardening and crack initiation as well as early stage crack propagation. Crack initiated at the surface of the riveted sheets as a result of high stress concentration and propagated oblique to the mating surface under the effect of fretting fatigue. The depth of damage due to fretting depended on the applied load and the cycle time. Microhardness measurements allowed the estimation of the depth of damage due to fretting. These results were observed to correlate well with the length of crack propagation.
A store‐operated current (SOC) mediates oxytocin autocontrol in the developing rat hypothalamus
Authors: Tobin Vicky , Gouty Laurie‐Anne , Moos Françoise C. , Desarménien Michel G. 
Published: July 2006

AbstractOxytocin (OT) and vasopressin (VP) autocontrol their secreting neurons in the supraoptic nucleus (SON) by modulating action potential firing through activation of specific metabotropic receptors. However, the mechanisms linking receptor activation to firing remain unknown. In almost all cell types, activation of plasma membrane metabotropic receptors triggers signalling cascades that induce mobilization of calcium from intracellular stores. In turn, emptying the calcium stores may evoke calcium influx through store‐operated channels (SOCs), the functions of which remain largely unknown in neurons. In this study, we show that these channels play a key role in the SON, at least in the response to OT. In isolated rat SON neurons, store depletion by thapsigargin induced an influx of calcium, demonstrating the presence of SOCs in these neurons. This calcium influx was specifically inhibited by 0.2 mm 1‐(2‐trifluoromethylphenyl‐)imidazole (TRIM). At 2 mm, this compound affected neither the resting electrophysiological properties nor the voltage‐dependant inward currents. In fresh slices, TRIM (2 mm) did not affect the resting potential of SON neurons, action potential characteristics, spontaneous action potential firing or synaptic activity; this compound thus appears to be a specific blocker of SOCs in SON neurons. TRIM (0.2 mm) specifically reduced the increase in action potential firing triggered by OT but did not affect the VP‐induced response. These observations demonstrate that store operated channels exist in hypothalamic neurons and specifically mediate the response to OT in the SON.
Role of the Preliminary Susceptibility Testing for Initial and After Failed Therapy of Helicobacter pylori Infection with Levofloxacin, Amoxicillin, and Esomeprazole
Authors: Marzio Leonardo , Coraggio Daniela , Capodicasa Simona , Grossi Laurino , Cappello Giorgio 
Published: July 2006

AbstractBackground:  Levofloxacin has been proposed as an alternative to classic therapy in secondary resistance to Helicobacter pylori.Aim:  To evaluate primary and secondary resistance of H. pylori to levofloxacin, and to test the role of susceptibility test on the efficacy of levofloxacin‐based triple therapy.Methods:  Eighty consecutive dyspeptic patients with positive 13C‐urea breath test never treated were randomly allocated into group A1 (40 patients) and group B1 (39 patients). Eighty‐three patients already treated unsuccessfully with positive 13C‐urea breath test were divided into group A2 (51 patients) and group B2 (32 patients). Patients in group A1 and group A2 underwent upper gastrointestinal endoscopy for H. pylori susceptibility test to amoxicillin, clarithromycin, tinidazole, rifabutin, and levofloxacin. These patients were treated with levofloxacin (500 mg b.i.d.), amoxicillin (1 g b.i.d.) and esomeprazole (20 mg b.i.d.) for 10 days if sensitive to these two antibiotics. If H. pylori was found resistant to amoxicillin and/or levofloxacin the treatment was based on the indications of the susceptibility test. Patients in group B1 and group B2 were treated empirically with levofloxacin, amoxicillin, and esomeprazole at the same dose and duration as group A. All patients underwent 13C‐urea breath test 2 months after the end of therapy.Results:  The antibiotic resistance of H. pylori strains in group A1 and group A2 was (%): amoxicillin: 2.4, 10; clarithromycin: 21.9, 43.1; tinidazole: 31.7, 70; rifabutin: 2.4, 4; and levofloxacin: 9.7, 12.2, respectively. In group A1 with susceptibility test‐driven therapy, eradication was 97.2%, and in group B1 with empirical treatment, 94.1% (n.s.). In group A2 with susceptibility test, eradication was 97.5%, whereas in group B2 with empirical treatment 81.2% (p < .01).Conclusion:  Primary and secondary resistance of H. pylori to levofloxacin is approximately 10% of the tested strains. The susceptibility test does not influence therapeutic outcome of triple therapy with amoxicillin and levofloxacin in patients never treated, while it is determinant for patients who were previously treated without success.
Bioinformatic Analysis of Helicobacter pylori XGPRTase: A Potential Therapeutic Target
Authors: Duckworth Megan , Ménard Armelle , Megraud Francis , Mendz George L. 
Published: July 2006

AbstractBackground:  Xanthine–guanine phosphoribosyltransferase (XGPRTase) is an enzyme of purine nucleotide salvage synthesis. The gpt gene of Helicobacter pylori has been annotated as encoding an XGPRTase and proposed as essential for survival of the bacterium in vitro. The aims of this work were to investigate the structure of H. pylori XGPRTase and to compare the key features of the enzyme to other phosphoribosyltransferases employing computational, modelling, and bioinformatic tools.Materials and Methods:  XGPRTase activity was measured in the cytosolic fraction of H. pylori by 31P‐nuclear magnetic resonance spectroscopy, and also in recombinant XGPRTase produced by a cell‐free expression system. Bioinformatics was employed to analyze the phylogeny of XGPRTase, and a structural model of the XGPRTase was built using threading techniques. The observed interactions of purine phosphoribosyltransferases with immucillin‐GP were used to study the theoretical interactions of H. pylori XGPRTase with this transition‐state analog.Results:  It was demonstrated that the gpt gene of H. pylori encodes a functional XGPRTase enzyme. Analyses of the XGPRTase sequence showed that the enzyme is significantly divergent from equivalent mammalian enzymes. Modelling served to identify specific features of the enzyme and key residues involved in catalysis.Conclusions:  The H. pylori XGPRTase is structurally similar to other phosphoribosyltransferase enzymes, but there were significant differences between the hood domain of H. pylori XGPRTase and other purine salvage phosphoribosyltransferases. Significant differences were found between the interactions of the H. pylori and human enzymes with a purine phosphoribosyltransferase inhibitor.
Antimicrobial Susceptibility of Helicobacter pylori Strains in a Random Adult Swedish Population
Authors: Storskrubb Tom , Aro Pertti , Ronkainen Jukka , Wreiber Karin , Nyhlin Henry , Bolling‐Sternevald Elisabeth , Talley Nicholas J. , Engstrand Lars , Agréus Lars 
Published: July 2006

AbstractBackground and Aim:  Antimicrobial resistance in Helicobacter pylori is a growing problem and has become an important factor leading to eradication failure. Information on antimicrobial susceptibility is important for selection of an optimum treatment regimen. The resistance rate in a random population has not been studied previously.Methods:  A random Swedish population sample (n = 3000, age 20–81 years) was surveyed using a mailed validated questionnaire assessing gastrointestinal symptoms (response rate of 74%). One‐third of the responders was invited, in random order, and accepted an esophagogastroduodenoscopy with biopsies for H. pylori culture and histology. Subjects were not treated for their H. pylori infection but a minimum inhibitory concentration of metronidazole, clarithromycin, amoxicillin, and tetracycline for the H. pylori isolates (n = 333) was determined by agar dilution. Prescribed antibiotic in the area was recorded.Results:  Irrespective of symptomatology, 16.2% of the isolated H. pylori strains were resistant to metronidazole, 1.5% to clarithromycin, 0% to amoxicillin, and 0.3% to tetracycline. The antibiotic consumption was low from an international perspective.Conclusion:  The resistance to the antibiotics was lower than expected from patient sample studies, especially for clarithromycin, most probably due to a restrictive prescription policy in the area. Introduction of a test‐and‐treat strategy in Sweden would only marginally affect the usage of clarithromycin.
Stroke and Chest Pain in Young People With Migraine
Authors: Hoffmann Michael 
Published: July 2006

Background.—Cerebrovascular and cardiovascular complications in migraineurs may be part of the migraine process and also consequent to triptan treatmentAim.—To determine the frequency, subtypes and associations of migraine‐associated stroke and angina in young people (18–49 years).Methods.—Patients were derived from a tertiary referral migraine and stroke registry. Migraine‐associated stroke was classified according to the four groups described by Welch and by the TOAST etiological stroke classification. A clinical description of angina during a migraine attack was required for the diagnosis of cardiac migraine without concomitant triptan or other vasoactive medicationsResults.—Of the young patients with stroke (349/1316; 26.5%), there were 30 (30/349; 8.6%) who had migraine at the time of stroke when categorized by the Welch classification type II to IV (type II n = 5, type III n = 2, type IV n = 3). Comparison of type I (n = 20) versus types II–IV (n = 10) showed significant difference (P= .03). Topographically the lesions were distributed into the partial anterior circulation (n = 8) and posterior circulation (n = 2) (P= .04). Comparison of anterior and posterior circulation territories of infarction indicated significant difference (n = 26/30 and 4/30; P= .01). The stroke etiological subtypes included cardiogenic (n = 5), atherogenic (n = 15), other (n = 5), and unknown (n = 5), with none diagnosed with small‐vessel cerebrovascular disease. Traditional stroke mechanistic entities (cardiac and atherogenic) differed significantly in comparison to the other and unknown categories P= .05. Cardiovascular patients with angina during a migraine attack (n = 9/1040; 0.9%), included IHS subtypes; migraine without aura (n = 4), migraine with aura (n = 4), and complicated migraine (n = 1). One patient required cardiac catheterization on account of significant ECG changes, with documented, reversible vasospasm.Conclusion.—(i) Migraine‐induced stroke remains controversial, with only two probable cases of type Welch III A+B in a large registry. (ii) Cardiac migraine may be a distinct entity requiring careful differentiation from triptan‐induced chest pain.
The effect of granular nematicide incorporation depth and potato planting depth on potatoes grown in land infested with the potato cyst nematodes Globodera rostochiensis and G. pallida
Authors: WOODS S R , HAYDOCK P P J 
Published: July 2006

SummaryField experiments at Harper Adams, Shropshire and Wisbech, Cambridgeshire investigated the effect of nematicide incorporation and seed tuber planting depth on the yield of the potato (Solamum tuberosum L.) cultivars Estima and Maris Piper and the population control of the potato cyst nematodes Globodera rostochiensis Woll. (Skarbilovich) and G. pallida (Stone). The nematicide fosthiazate was applied at 3 kg−1 ha and either not incorporated, or incorporated to 20 cm or 35 cm. Potatoes were mechanically planted to three depths; approximately 10 cm, 15 cm and 25 cm.Incorporation to 20 cm with tubers planted at a depth of 10 cm or 15 cm, reduced root invasion compared with the other treatments. Incorporating nematicide to 20 cm also gave consistently higher ware yields and better nematode control than the other incorporation methods, which were not significantly different to the control. However, ware yield and nematode multiplication rate were not significantly affected by planting depth.
Physiological ageing of potato tubers: A Review
Authors: COLEMAN WARREN K 
Published: July 2006

SummaryNumerous theories have been proposed to describe the complex process of ageing in biological systems. Two general groups of ageing theories currently exist: 1) stochastic where the accumulation of random molecular damage leads to loss of information vital to the cell; and, 2) systemic where an organised, genetically based sequence of metabolic activities leads to programmed ageing. Whether these are acceptable models of ageing in potato tubers is unknown although the tuber could provide a useful experimental system for studying ageing. An initial requirement for advancing the concept of ageing in potato tubers must centre on the development of a suitable ageing index. A review of the literature suggests that a modified approach to ‘sprouting capacity’ and ‘incubation period’ may allow tuber ageing to be described in mathematical terms that would, in turn, facilitate the development of a physiological ageing index as well as temperature sensitive predictive models. Although a number of biochemical studies of ageing have been pursued, the development of adequate biomarkers has yet to achieve a coordinated level of development as found in a range of organisms. For example, ageing in other biological systems may be viewed as an outcome of an accumulation of random molecular damage and may be primarily caused by a changing balance between reactive oxygen species and diminishing levels of protective agents such as superoxide dismutase, alpha‐tocopherol or vitamin C. The exploration of these and similar problems in the context of appropriate modelling approaches should allow a better understanding of physiological ageing in potato tubers.
Micropropagation of three berry fruit species using nodal segments from field‐grown plants
Authors: GONZALEZ M V , LOPEZ M , VALDES A E , ORDAS R J 
Published: July 2006

SummaryPlant micropropagation of blueberry (Vaccinium corymbosum L. cv. Berkeley), blackberry (Rubus sp. cv. Smoothstem) and raspberry (Rubus idaeus L. cv. Gradina) was carried out from nodal segments of adult field‐grown plants. Hardwood and softwood cuttings were studied as explant sources. The cultures successfully established were softwood from all three species, and hardwood only from blueberry. Shoot‐bud establishment from blueberry was achieved by culturing explants in WPM salts with MS vitamins for 15 days, and then 30 days in the same medium with 18 mM Zeatin. The best results of multiplication were obtained in the same medium with 25 mM 2iP. For blackberry, shoot‐bud establishment was achieved by culturing explants in MS medium for 15 days, and then in the same medium with 4 mM BA and 0.25 mM IBA. This medium was also the best for blackberry multiplication. Raspberry explants (cvs Gradina and Willamette) were cultured in MS medium for 15 days and then transferred to MS medium supplemented with 4 μm BA and 0.25 mM IBA. After 30 days of culture, only ‘Gradina’ explants survived, from which shoot‐bud establishment was obtained in a modified MS medium (Anderson's macronutrients except calcium, with Sequestrene as the iron source) with the same growth regulators. Multiplication was achieved by subculturing explants in the same medium either with 4 mM BA plus 0.25 mM IBA or with 8 mM BA plus 0.25 mM IBA. Shoots of at least 1 cm in length from all species were rooted ex vitro in a mixture of peat and Perlite (1:1, v/v) in a mist chamber, and 100% of rooting plants were acclimated. Bacterial, fungal and viral diseases were detected in stock plants, while tests carried out in both shoots and regenerated plants revealed the absence of any kind of disease.