bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconstruction of the Atrophic Edentulous Maxilla with Free Iliac Crest Grafts and Implants: A 3‐Year Report of a Prospective Clinical Study
Authors: Sjöström Mats , Sennerby Lars , Nilson Hans , Lundgren Stefan
Published: February 2007

Purpose:  The purpose of this study was to perform a longitudinal follow‐up study of implant stability in grafted maxillae with the aid of clinical, radiological, and resonance frequency analysis (RFA) parameters.

Materials and Methods:  The atrophic edentulous maxillae in 29 patients were reconstructed with free iliac crest grafts using onlay/inlay or interpositional grafting techniques. The endpoint of the resorption pattern in the maxilla determined the grafting technique used. Endosteal implants were placed after 6 months of bone‐graft healing. Implant stability was measured four times using RFA: when the implants were placed, after 6 to 8 months of healing, after 6 months and 3 years of bridge loading. Individual checkups were performed at the two later RFA registrations after removal of the supraconstructions (Procera® Implant Bridge, Nobel Biocare AB, Göteborg, Sweden). Radiological follow up of marginal bone level was performed annually.

Results:  Twenty‐five patients remained for the follow‐up period. A total of 192 implants were placed and with a survival rate of 90% at the 3‐year follow up. Women and an implant position with a class 6 resorption prior to reconstruction were factors with significant increased risk for implant failure (multivariate logistic regression). Twelve of the 20 failed implants were lost before loading (early failures). The change in the marginal bone level was 0.3 ± 0.3 mm between baseline (bridge delivery) and the 3‐year follow up. The implant stability quotient (ISQ) value for all implants differed significantly between abutment connection (60.2 ± 7.3) and after 6 months of bridge loading (62.5 ± 5.5) (Wilcoxon signed ranks test for paired data, p=.05) but were nonsignificant between 6 months of bridge loading and 3 years of bridge loading (61.8 ± 5.5). There was a significant difference between successful and failed implants when the ISQ values were compared for individual implants at placement (Mann‐Whitney U test, p=.004). All 25 patients were provided with fixed implant bridges at the time of the 3‐year follow up.

Conclusion:  This clinical follow up using radiological examinations and RFA measurements indicates a predictable and stable long‐term result for patients with atrophic edentulous maxillae reconstructed with autogenous bone and with delayed placement of endosteal implants. The ISQ value at the time of placement can probably serve as an indicator of level of risk for implant failure.
One Approach to Formulating and Evaluating Student Work Groups in Legal Environment of Business Courses
Authors: Camara Joan E. , Carr B. Nathaniel , Grota Barbara L.
Published: February 2007

The principal focus of this study is an investigation of whether students' grade point average (GPA) is a viable criterion for forming student work groups in the undergraduate Legal Environment of Business course. More specifically, the research focuses on the impact of: (1) GPA‐homogeneous (HO) and GPA‐heterogeneous (HE) groups upon student satisfaction with group processes and (2) the impact on individual student performance in both group and nongroup assignments. Data obtained from fourteen HE and fourteen HO student groups, in four separate Legal Environment of Business classes consisting of a mix of Management, Marketing, Computer Information Systems, International Business, Financial Services, and Accounting majors, generated a number of significant results. The most surprising observations dealt with the behavior of low achievers whose individual grades showed substantial improvement after working in HO groups. Researchers who are assessing pedagogical methods which serve to engage a student's active learning and motivation should find these results to be of interest. In addition, the beneficial impact on task and relationship behaviors observed in this study should provide solace or a sense of reward to the larger set of academicians, across disciplines, who attempt to impart realistic organizational skills to their classes.
Apheresis in Coronary Heart Disease With Elevated Lp (a): A Review of Lp (a) As a Risk Factor and Its Management
Authors: Keller Christiane
Published: February 2007

Abstract:  Lipoprotein (a) (Lp (a)) increases global cardiovascular risk, especially when LDL cholesterol is concomitantly elevated. Epidemiologic data show that Lp (a) concentration in plasma can be used to predict the risk of early atherogenesis in a dose‐dependent manner and late stages of atherosclerosis are accelerated by elevated Lp (a). Therapeutic means to lower Lp (a) are limited. The most effective method to reduce plasma Lp (a) concentration significantly is therapeutic apheresis. Because apheresis is laborious and expensive, patients considered for this procedure should suffer from high Lp (a) concentrations, well beyond 50 mg/dL, and have manifested and progressive coronary heart disease despite maximal drug therapy. Experimental data and therapeutic results will be discussed in the present paper.
Influence of Leukocytapheresis Therapy for Ulcerative Colitis on Anemia and Hemodynamics
Authors: Miyamoto Hiroshi , Okahisa Toshiya , Iwaki Hiroshi , Murata Masahiko , Ito Susumu , Nitta Yoshinori , Akutagawa Masatake , Kinouchi Yohsuke , Ohnishi Yoshiaki , Oto Jun , Nishimura Masaji
Published: February 2007

Abstract:  In Japan, leukocytapheresis (LCAP) therapy has been carried out for ulcerative colitis as an effective therapy with a low incidence of side‐effects. In the present study, we serially investigated the influence of LCAP therapy on anemia and hemodynamics in patients with ulcerative colitis using a non‐invasive method with a Crit‐Line monitor (CLM) (Hema Metrics Inc., Salt Lake City, UT and Boston, MA, USA). We carried out LCAP on 10 patients with ulcerative colitis using a CS‐100 Cellsorba EX LCAP filter in 34 courses of LCAP. The mean hematocrit value, which was measured using the Crit‐Line monitor, was 21.8 ± 0.2% (21.0–22.4%), which showed no significant changes after each LCAP therapy. The actual erythrocyte count, hemoglobin and hematocrit values decreased by 244 000/mm3, 0.7 g/dL and 2.1%, respectively, however, the differences were insignificant. These values corresponded to 7.8, 8.0 and 7.6% of the values before LCAP, respectively. There were no significant changes in systolic blood pressure, diastolic blood pressure, or heart rate during LCAP. The results of this study suggest that one course of LCAP does not exacerbate anemia, and it does not influence hemodynamics. However, considering the exacerbation of anemia in patients with severe ulcerative colitis caused by massive melena, monitoring with a less invasive Crit‐Line monitor and a vital information monitor might be useful.
A Novel Method for Dry Weight Assessment in Hemodialysis Patients: Utilization of Inferior Vena Cava Flat Ratio to Correct for Individual Variations in Vessel Diameter
Authors: Naruse Mashiro , Sakaguchi Shunichi , Nakayama Yushi , Nonoguchi Hiroshi , Tomita Kimio
Published: February 2007

Abstract:  Measurement of the inferior of vena cava (IVC) diameter by ultrasonography (US) has been shown to be useful for assessing dry weight (DW) in hemodialysis (HD) patients. We have previously observed some cases in which the IVC diameter differed depending on whether measurements were obtained from sagittal or cross‐sectional images. Thus, in the present study we introduce a new concept, the flat ratio, to define the magnitude of IVC deflation. The flat ratio of the IVC (F‐IVC) is determined from cross‐sectional ultrasonographic images of the IVC. The present study showed that F‐IVC is significantly correlated with changes in body weight (ΔBW(%)). Similarly, the change in F‐IVC (ΔF‐IVC) during HD is correlated with ΔBW(%) but not with changes in systolic or diastolic blood pressure during HD. The results of the present study suggest that F‐IVC measurement can serve as a useful tool for DW assessment.
Midodrine Hydrochloride and l‐threo‐3,4‐dihydroxy‐Phenylserine Preserve Cerebral Blood Flow in Hemodialysis Patients With Orthostatic Hypotension
Authors: Fujisaki Kiichiro , Kanai Hidetoshi , Hirakata Hideki , Nakamura Sachiko , Koga Yuko , Hattori Fumitada , Iida Mitsuo
Published: February 2007

Abstract:  Orthostatic hypotension (OH) after hemodialysis (HD) is a serious complication, as it causes various neurological symptoms and even ischemic brain damage. The aim of the present study was to evaluate the effects of antihypotensive agents, midodrine hydrochloride (MID) and l‐threo‐3,4‐dihydroxyphenylserine (L‐DOPS), on OH after HD. We measured systolic blood pressure (SBP) and cerebral blood flow velocity in the middle cerebral artery (MCVm, by transcranial Doppler sonography), in patients with OH during a 5‐min 60‐degree head‐up tilt test at both before and after 4‐week treatment with MID at 4 mg/day (N = 6) or L‐DOPS at 400 mg/day (N = 7). Both MID and L‐DOPS did not significantly protect against falls in systolic BP (SBP) after passive head‐up tilt. However, a significant improvement was achieved in MCVm‐decrement in the MID group at 3 min and the L‐DOPS group at 0, 1 and 3 min during head‐up tilt. Although MID and L‐DOPS did not prevent OH after HD in HD patients, both agents preserved cerebral blood flow during orthostasis in HD patients with OH.
A Case Report of Long‐term Remission of Ulcerative Colitis After Lymphocyto‐plasmapheresis
Authors: Liumbruno Giancarlo Maria , Centoni Paolo Emilio , Niccoli Giovanni , Liotta Francesco , Metelli Maria Rita , Annunziato Francesco , Molfettini Pietra , Frosali Francesca , Maggi Laura , Sodini Maria Laura
Published: February 2007

Abstract:  Ulcerative colitis (UC) is a chronic inflammatory bowel disease of the colorectum, with mucosal infiltration by activated leukocytes, which are the result of complex interactions between lymphocytes, antigen, and dendritic cells (DCs). We carried out lymphocyto‐plasmapheresis (LCPA) in a UC patient with the aim of removing lymphocytes, DCs and inflammatory cytokines (ICKs). A 42‐year‐old female with UC in moderate activity phase was submitted to 5 weekly LCPA treatments. Before and after LCPA we monitored: (i) the percentage of T, B, NK lymphocytes, monocytes, and peripheral blood lymphoid and myeloid DCs; (ii) the T lymphocyte subpopulations; (iii) the ICKs; and (iv) the immune complexes (IC). We achieved the interruption of all pharmacological therapies, and so far the clinical and histological remission has lasted for 24 months. The flow cytometric assessment of the leukocyte subpopulations did not show any relevant variation of their numbers after LCPA, while TNFα, IL‐6, IL‐12 and serum IgG‐C1q ICs decreased. In the present case, the contemporary depletion of plasma, lymphocytes and DCs, allowed LCPA to emerge as an efficient alternative to UC pharmacological therapy without affecting the number of white blood cells, DCs and leukocyte subpopulations that were assessed. Further studies are needed both to address LCPA mechanism of action and optimal apheresis protocol, and to compare this form of therapy to a placebo control group.
A Case Report of Hemodialysis Intolerance With Eosinophilia
Authors: Higuchi Terumi , Yamazaki Toshio , Ohnishi Yoshihiko , Matsumoto Shiro , Yabuki Minako , Kitajima Syoko , Toshida Yoshinori , Maruyama Noriaki , Oikawa Osamu , Okada Kazuyoshi , Fukuda Noboru , Soma Masayoshi , Matsumoto Koichi
Published: February 2007

Abstract:  We report the case of a patient who developed eosinophilia during hemodialysis and became intolerant to dialysis therapy. The patient, a 40‐year‐old woman, was initiated on hemodialysis for end‐stage renal failure caused by chronic glomerulonephritis. After starting on dialysis, her eosinophil count gradually increased. During the ninth session, she developed abdominal pain of an unknown cause after approximately 1 h of dialysis. The symptom, which persisted in the following sessions, was considered to be a dialysis‐related complication. We attempted different dialyzers and anticoagulants, but without improvement. The dialysis therapy was discontinued and steroid treatment was given. The hypereosinophilic condition improved rapidly and dialysis therapy was restarted successfully without causing abdominal pain. To investigate the cause of this problem, we measured the leukocyte count and anaphylatoxin C3a level in peripheral blood during dialysis, and compared the results before and after steroid treatment. The results showed that the significant decrease in the leukocyte count observed before steroid treatment was reduced to a mild decrease after steroid treatment. In contrast, C3a did not show a significant difference between the values obtained before and after steroid treatment. These findings suggest that eosinophilia played an important role in the etiology of dialysis intolerance and that C3a was not involved in the decrease in leukocytes under the conditions experienced by the present patient.
The carbon star IRC+10216: linking the complex inner region with its spherical large-scale structures
Authors: Menut J.-L. , Gendron E. , Schartmann M. , Tuthill P. , Lopez B. , Danchi W. C. , Wolf S. , Lagrange A.-M. , Flament S. , Rouan D. , Clénet Y. , Berruyer N.
Published: February 2007

IRC+10216 is located at the tip of the asymptotic giant branch of the Hertzsprung–Russell diagram in a transition phase toward the post-asymptotic giant branch stage. Its study contributes to our knowledge of the late stage of stellar evolution of low- and intermediate-mass stars, when the circumstellar matter begins to adopt the asymmetric or bipolar forms commonly found in planetary nebulae. Using the NAOS–CONICA (NACO) adaptive optics system, we have mapped the circumstellar environment of IRC+1O216 at several wavelengths and three different epochs. The NACO study provides high-resolution and high-dynamic-range information on the different features displayed by the circumstellar envelope: clumpiness and a peanut- or bipolar-like shape at small scales. The link between the inner regions and the spherical-like shells observed at large scales is displayed in these high-dynamic-range data.
On the size of Hii regions around high-redshift quasars
Authors: Maselli A. , Gallerani S. , Ferrara A. , Choudhury T. R.
Published: February 2007

We investigate the possibility of constraining the ionization state of the intergalactic medium (IGM) close to the end of reionization (z≈ 6) by measuring the size of H ii regions in high-z quasar spectra. We perform a combination of multiphase smoothed particle hydrodynamics and three-dimensional radiative transfer simulations to predict reliably the properties of typical high-z quasar H ii regions, embedded in a partly neutral IGM (xH i= 0.1). In this work we assume a fixed configuration for the quasar lifetime and luminosity, i.e. tQ= 107 yr and . From the analysis of mock spectra along lines of sight through the simulated QSO environment, we find that the H ii region size derived from quasar spectra is on average 30 per cent smaller than the physical one. Additional maximum likelihood analysis shows that this offset induces an overestimate of the neutral hydrogen fraction, xH i, by a factor of ≈3. By applying the same statistical method to a sample of observed QSOs, our study favours a mostly ionized (xH i < 0.06) universe at z= 6.1.
TEXTURAL CHARACTERISTICS OF BEEF MUSCLES
Authors: SEGARS RONALD A. , NORDSTROM HAROLD A. , KAPSALIS JOHN G.
Published: February 2007

Uniaxial compression tests were performed on raw and cooked meat samples prepared from five muscles excised from a single beef hindquarter. The greatest variation of mechanical properties was across the muscle (lateral to medial) rather than along the muscle (origin to insertion). Active muscles showed greater variation and were generally tougher than inactive muscles. By carefully following regions of similar characteristics from raw to cooked slices, linear regression curves for raw vs cooked beef were obtained having correlation coefficients averaging 0.87.
OBSERVATIONS ON TEXTURE MEASUREMENT OF RAW CUCUMBERS WITH THE FRUIT PRESSURE TESTER*
Authors: BREENE WILLIAM M. , JEON I. J. , BERNARD STUART N.
Published: February 2007

Raw fruit of a ‘firm’ (Explorer) and a ‘soft’ (Green F) cucumber cultivar were puncture tested with the Magness‐Taylor fruit pressure tester (FPT) manually, and also with the FPT or only FPT tip mounted in the Instron. Puncture‐values for flesh only were 70–75 % of those for intact fruit. Neither the cucumber size (1–2.5 in. diam) nor the test speed (5–50 cm min‐1) appreciably affected the puncture test values.
Review article: issues in acid‐related disorders in children in Asian countries
Authors: CHAN F. K. L. , GOLD B. D.
Published: February 2007

Major points of controversy identified by the workshop included:

(i) symptom assessment of acid‐related disorders in children, where vomiting was identified as a potential confounding feature, abdominal pain as a common feature of paediatric gastro‐oesophageal reflux disease;

(ii) extra‐oesophageal manifestations of paediatric gastro‐oesophageal reflux disease;

(iii) abdominal pain perceived as a common feature of Helicobacter pylori‐related disorders;

(iv) role of testing for H. pylori in children;

(v) test‐and‐treat strategies for H. pylori infection in children before long‐term proton pump inhibitor therapy;

(vi) an underutilization of triple therapy and proton pump inhibitors in children in areas with a high prevalence of H. pylori infection;

(vii) the role of empiric proton pump inhibitor therapy in children.
Review article: exploring strategies to improve treatment outcomes and compliance in specific patient groups with acid–related disorders
Authors: GOLD B. D. , KINOSHITA Y. , CHANG W.‐H. , VIVATVAKIN B. , OVARLARNPORN B. , CHAN F. K. L.
Published: February 2007

Specific patient groups consisting of those with nasogastric or gastrostom feeding tubes such as those with stroke neurological impairment or other etiologies, patients with difficulty swallowing (i.e. oral pharyngeal dysfunction), unconscious patients and children who dislike or refuse taking or cannot swallow tablets require special attention with regard to the pharmacological treatment of acid‐related disorders.

In particular, these groups of patients require special formulations in order to achieve optimal compliance with acid suppression therapy. Formulations such as the syrup histamine (H2)‐receptor antagonist in a syrup formulation, or for proton pump inhibitors, either the multiple unit pellet capsules, fast dissolving tablets or intravenous formulations, can be used to overcome swallowing problems or bitter taste.
Fast screening of municipal wastewater components by reversed‐phase chromatography coupled to ultraviolet‐diode array detection
Authors: Vlessidis Athanasios G. , Kotti Melina E. , Giokas Dimosthenis L. , Evmiridis Nicholaos P.
Published: February 2007

The screening of ingredients in municipal wastewater samples was studied, by reverse‐phase high‐performance liquid chromatography (RP‐HPLC) implemented with a ultraviolet (UV)‐diode array detector, in an effort to establish a quick screening method for finding the main UV‐absorbing components of the wastewater that enters the biological treatment plant. For the purposes of direct comparison of the chromatograms obtained, a single sample taken from the inlet of municipal biological treatment plant was used for all experimental tests and the optimal elution conditions were established by detailed investigation through isocratic and gradient elution techniques. The optimal column resolution was reached by testing a broad range of capacity and selectivity factor values. The criterion used for validating the complete separation of solutes was based on the spectral purity of eluted chromatogram peaks and on the stability of retention time of a peak in real‐time chromatograms taken at different wavelengths during the elution process. From this research work, it was found that the overall chromatogram peak pattern was sensitive to the mobile phase composition and solvent system but under fixed elution conditions, the pattern of the major peaks was stable and depended on the composition of the wastewater sample. By testing different types of elution modes, it was found that the best column resolution was obtained under programmed isocratic‐gradient elution using a binary mobile phase. Finally, a relatively high column resolution method is reported for fragmentation of municipal wastewater samples.
Norms of Assertion
Authors: Weiner Matt
Published: February 2007

Recently attention has been paid to the epistemic requirements for proper assertion. The most popular account has been the knowledge account, that we can only properly assert what we know. Others have criticized the knowledge account and argued that the norm of assertion is truth, belief, or assertion of what it is reasonable to believe.
Simples and Gunk
Authors: Hudson Hud
Published: February 2007

Are there any non‐composite objects? Are there any objects every part of which is composite? Are items of either kind even possible? What would they be like? Of what significance would they be? How best can we come to have reasonable beliefs about the answers to these inquiries? Such questions – about the actuality and possibility, the analysis and significance, the methodology and epistemology of simples and pieces of gunk – have been center stage in recent contemporary analytic metaphysics. The following article provides a general overview of some of the current debates on their proper answers as well as a pair of slightly more detailed investigations into two issues of special interest in the recent literature devoted to these topics.
Lost and found: the enigmatic large‐billed reed warbler Acrocephalus orinus rediscovered after 139 years
Authors: D. Round Philip , Hansson Bengt , J. Pearson David , R. Kennerley Peter , Bensch Staffan
Published: February 2007

We present compelling evidence of the continued existence of the large‐billed reed warbler Acrocephalus orinus, hitherto known only from the unique type specimen collected in NW India 139 years ago. Morphological and genetic analyses of an unusual Acrocephalus warbler mist‐netted south‐west of Bangkok, Thailand, on 27 March 2006, confirmed its identity as A. orinus, and revealed that it was heterozygous at four out of eight microsatellite markers, indicating the continued existence of a viable population whose breeding and wintering areas are still unknown.
Synaptic modifications at the CA3–CA1 synapse after chronic AMPA receptor blockade in rat hippocampal slices
Authors: Mateos José María , Lüthi Andreas , Savic Natasa , Stierli Beat , Streit Peter , Gähwiler Beat H. , McKinney R. Anne
Published: February 2007

Maintenance of dendritic spines, the postsynaptic elements of most glutamatergic synapses in the central nervous system, requires continued activation of AMPA receptors. In organotypic hippocampal slice cultures, chronic blockade of AMPA receptors for 14 days induces a substantial loss of dendritic spines on CA1 pyramidal neurons. Here, using serial section electron microscopy, we show that loss of dendritic spines is paralleled by a significant reduction in synapse density. In contrast, we observed an increased number of asymmetric synapses onto the dendritic shaft, suggesting that spine retraction does not inevitably lead to synapse elimination. Functional analysis of the remaining synapses revealed that hippocampal circuitry compensates for the anatomical loss of synapses by increasing synaptic efficacy. Moreover, we found that the observed morphological and functional changes were associated with altered bidirectional synaptic plasticity. We conclude that continued activation of AMPA receptors is necessary for maintaining structure and function of central glutamatergic synapses.
Subunit‐specific mechanisms and proton sensitivity of NMDA receptor channel block
Authors: Dravid Shashank M. , Erreger Kevin , Yuan Hongjie , Nicholson Katherine , Le Phuong , Lyuboslavsky Polina , Almonte Antoine , Murray Ernest , Mosley Cara , Barber Jeremy , French Adam , Balster Robert , Murray Thomas F. , Traynelis Stephen F.
Published: February 2007

We have compared the potencies of structurally distinct channel blockers at recombinant NR1/NR2A, NR1/NR2B, NR1/NR2C and NR1/NR2D receptors. The IC50values varied with stereochemistry and subunit composition, suggesting that it may be possible to design subunit‐selective channel blockers. For dizocilpine (MK‐801), the differential potency of MK‐801 stereoisomers determined at recombinant NMDA receptors was confirmed at native receptorsin vitroandin vivo. Since the proton sensor is tightly linked both structurally and functionally to channel gating, we examined whether blocking molecules that interact in the channel pore with the gating machinery can differentially sense protonation of the receptor. Blockers capable of remaining trapped in the pore during agonist unbinding showed the strongest dependence on extracellular pH, appearing more potent at acidic pH values that promote channel closure. Determination of pKavalues for channel blockers suggests that the ionization of ketamine but not of other blockers can influence its pH‐dependent potency. Kinetic modelling and single channel studies suggest that the pH‐dependent block of NR1/NR2A by (−)MK‐801 but not (+)MK‐801 reflects an increase in the MK‐801 association rate even though protons reduce channel open probability and thus MK‐801 access to its binding site. Allosteric modulators that alter pH sensitivity alter the potency of MK‐801, supporting the interpretation that the pH sensitivity of MK‐801 binding reflects the changes at the proton sensor rather than a secondary effect of pH. These data suggest a tight coupling between the proton sensor and the ion channel gate as well as unique subunit‐specific mechanisms of channel block.
l‐Arginine currents in rat cardiac ventricular myocytes
Authors: Peluffo R. Daniel
Published: February 2007

l‐Arginine (l‐Arg) is a basic amino acid that plays a central role in the biosynthesis of nitric oxide, creatine, agmantine, polyamines, proline and glutamate. Most tissues, including myocardium, must import l‐Arg from the circulation to ensure adequate intracellular levels of this amino acid. This study reports novel l‐Arg‐activated inward currents in whole‐cell voltage‐clamped rat ventricular cardiomyocytes. Ion‐substitution experiments identified extracellular l‐Arg as the charge‐carrying cationic species responsible for these currents, which, thus, represent l‐Arg import into cardiac myocytes. This result was independently confirmed by an increase in myocyte nitric oxide production upon extracellular application of l‐Arg. The inward movement of Arg molecules was found to be passive and independent of Na2+, K2+, Ca2+ and Mg2+. The process displayed saturation and membrane potential (Vm)‐dependent kinetics, with a K0.5 for l‐Arg that increased from 5 mm at hyperpolarizing Vm to 20 mm at +40 mV. l‐Lysine and l‐ornithine but not d‐Arg produced currents with characteristics similar to that activated by l‐Arg indicating that the transport process is stereospecific for cationic l‐amino acids. l‐Arg current was fully blocked after brief incubation with 0.2 mmN‐ethylmaleimide. These features suggest that the activity of the low‐affinity, high‐capacity CAT‐2A member of the y2+ family of transporters is responsible for l‐Arg currents in acutely isolated cardiomyocytes. Regardless of the mechanism, we hypothesize that a low‐affinity arginine transport process in heart, by ensuring substrate availability for sustained NO production, might play a cardio‐protective role during catabolic states known to increase Arg plasma levels severalfold.
Distribution of IP3‐mediated calcium responses and their role in nuclear signalling in rat basolateral amygdala neurons
Authors: Power John M. , Sah Pankaj
Published: February 2007

Metabotropic receptor activation is important for learning, memory and synaptic plasticity in the amygdala and other brain regions. Synaptic stimulation of metabotropic receptors in basolateral amygdala (BLA) projection neurons evokes a focal rise in free Ca2+ in the dendrites that propagate as waves into the soma and nucleus. These Ca2+ waves initiate in the proximal dendrites and show limited propagation centrifugally away from the soma. In other cell types, Ca2+ waves have been shown to be mediated by either metabotropic glutamate receptor (mGluR) or muscarinic receptor (mAChR) activation. Here we show that mGluRs and mAChRs act cooperatively to release Ca2+ from inositol 1,4,5‐trisphosphate (IP3)‐sensitive intracellular Ca2+ stores. Whereas action potentials (APs) alone were relatively ineffective in raising nuclear Ca2+, their pairing with metabotropic receptor activation evoked an IP3‐receptor‐mediated Ca2+‐induced Ca2+ release, raising nuclear Ca2+ into the micromolar range. Metabotropic‐receptor‐mediated Ca2+‐store release was highly compartmentalized. When coupled with metabotropic receptor stimulation, large robust Ca2+ rises and AP‐induced amplification were observed in the soma, nucleus and sparsely spiny dendritic segments with metabotropic stimulation. In contrast, no significant amplification of the Ca2+ transient was detected in spine‐dense high‐order dendritic segments. Ca2+ rises evoked by photolytic uncaging of IP3 showed the same distribution, suggesting that IP3‐sensitive Ca2+ stores are preferentially located in the soma and proximal dendrites. This distribution of metabotropic‐mediated store release suggests that the neuromodulatory role of metabotropic receptor stimulation in BLA‐dependent learning may result from enhanced nuclear signalling.
Inflammation reduces the contribution of N‐type calcium channels to primary afferent synaptic transmission onto NK1 receptor‐positive lamina I neurons in the rat dorsal horn
Authors: Rycroft Beth K. , Vikman Kristina S. , Christie MacDonald J.
Published: February 2007

N‐type calcium channels contribute to the release of glutamate from primary afferent terminals synapsing onto nocisponsive neurons in the dorsal horn of the spinal cord, but little is known of functional adaptations to these channels in persistent pain states. Subtype‐selective conotoxins and other drugs were used to determine the role of different calcium channel types in a rat model of inflammatory pain. Electrically evoked primary afferent synapses onto lumber dorsal horn neurons were examined three days after induction of inflammation with intraplantar complete Freund's adjuvant. The maximal inhibitory effect of the N‐type calcium channel blockers, ω‐conotoxins CVID and MVIIA, were attenuated in NK1 receptor‐positive lamina I neurons after inflammation, but the potency of CVID was unchanged. This was associated with reduced inhibition of the frequency of asynchronous‐evoked synaptic events by CVID studied in the presence of extracellular strontium, suggesting reduced N‐type channel contribution to primary afferent synapses after inflammation. After application of CVID, the relative contributions of P/Q and L channels to primary afferent transmission and the residual current were unchanged by inflammation, suggesting the adaptation was specific to N‐type channels. Blocking T‐type channels did not affect synaptic amplitude under control or inflamed conditions. Reduction of N‐type channel contribution to primary afferent transmission was selective for NK1 receptor‐positive neurons identified by post hoc immunohistochemistry and did not occur at synapses in laminae IIo or IIi, or inhibitory synapses. These results suggest that inflammation selectively downregulates N‐type channels in the terminals of primary afferents synapsing onto (presumed) nociceptive lamina I NK1 receptor‐positive neurons.
Effects of flecainide and quinidine on arrhythmogenic properties of Scn5a+/− murine hearts modelling the Brugada syndrome
Authors: Stokoe Kate S. , Balasubramaniam Richard , Goddard Catharine A. , Colledge William H. , Grace Andrew A. , Huang Christopher L.‐H.
Published: February 2007

Brugada syndrome (BrS) is associated with a loss of Na+ channel function and an increased incidence of rapid polymorphic ventricular tachycardia (VT) and sudden cardiac death. A programmed electrical stimulation (PES) technique assessed arrhythmic tendency in Langendorff‐perfused wild‐type (WT) and genetically modified (Scn5a+/−) ‘loss‐of‐function’ murine hearts in the presence and absence of flecainide and quinidine, and the extent to which Scn5a+/− hearts model the human BrS. Extra‐stimuli (S2), applied to the right ventricular epicardium, followed trains of pacing stimuli (S1) at progressively reduced S1–S2 intervals. These triggered VT in 16 out of 29 untreated Scn5a+/− and zero out of 31 WT hearts. VT occurred in 11 out of 16 (10 μm) flecainide‐treated WT and nine out of the 13 initially non‐arrhythmogenic Scn5a+/− hearts treated with (1.0 μm) flecainide. Quinidine (10 μm) prevented VT in six out of six flecainide‐treated WT and 13 out of the 16 arrhythmogenic Scn5a+/− hearts in parallel with its clinical effects. Paced electrogram fractionation analysis demonstrated increased electrogram durations, expressed as electrogram duration (EGD) ratios, with shortening S1–S2 intervals in arrhythmogenic Scn5a+/− hearts, and prolonged ventricular effective refractory periods (VERPs) in non‐arrhythmogenic Scn5a+/− hearts. Flecainide increased EGD ratios in WT (at 10 μm) and non‐arrhythmogenic Scn5a+/− hearts (at 1.0 μm), whereas quinidine (10 μm) reduced EGD ratios and prolonged VERPs in WT and arrhythmogenic Scn5a+/− hearts. However, epicardial and endocardial monophasic action potential recordings consistently demonstrated positive gradients of repolarization in WT, arrhythmogenic and non‐arrhythmogenic Scn5a+/− hearts under all pharmacological conditions. Together, these findings demonstrate proarrhythmic effects of flecainide in WT and Scn5a+/− murine hearts that recapitulate its clinical effects. They further attribute the arrhythmogenic phenomena observed here to re‐entrant substrates resulting from delayed epicardial activation despite an absence of transmural heterogeneities of repolarization, in sharp contrast to recent characterizations in ‘gain‐of‐function’Scn5a+/Δ murine hearts modelling the long‐QT(3) syndrome.
An Active Subglacial Water System in West Antarctica Mapped from Space
Authors: Fricker Helen Amanda , Scambos Ted , Bindschadler Robert , Padman Laurie
Published: February 2007

Satellite laser altimeter elevation profiles from 2003 to 2006 collected over the lower parts of Whillans and Mercer ice streams, West Antarctica, reveal 14 regions of temporally varying elevation, which we interpret as the surface expression of subglacial water movement. Vertical motion and spatial extent of two of the largest regions are confirmed by satellite image differencing. A major, previously unknown subglacial lake near the grounding line of Whillans Ice Stream is observed to drain 2.0 cubic kilometers of water into the ocean over ∼3 years, while elsewhere a similar volume of water is being stored subglacially. These observations reveal a wide spread, dynamic subglacial water system that may exert an important control on ice flow and mass balance.
Thermoelectricity in Molecular Junctions
Authors: Reddy Pramod , Jang Sung-Yeon , Segalman Rachel A. , Majumdar Arun
Published: February 2007

By trapping molecules between two gold electrodes with a temperature difference across them, the junction Seebeck coefficients of 1,4-benzenedithiol (BDT), 4,4′-dibenzenedithiol, and 4,4′′-tribenzenedithiol in contact with gold were measured at room temperature to be +8.7 ± 2.1 microvolts per kelvin (μV/K), +12.9 ± 2.2 μV/K, and +14.2 ± 3.2 μV/K, respectively (where the error is the full width half maximum of the statistical distributions). The positive sign unambiguously indicates p-type (hole) conduction in these heterojunctions, whereas the Au Fermi level position for Au-BDT-Au junctions was identified to be 1.2 eV above the highest occupied molecular orbital level of BDT. The ability to study thermoelectricity in molecular junctions provides the opportunity to address these fundamental unanswered questions about their electronic structure and to begin exploring molecular thermoelectric energy conversion.
Room-Temperature Quantum Hall Effect in Graphene
Authors: Novoselov K. S. , Jiang Z. , Zhang Y. , Morozov S. V. , Stormer H. L. , Zeitler U. , Maan J. C. , Boebinger G. S. , Kim P. , Geim A. K.
Published: February 2007

The quantum Hall effect (QHE), one example of a quantum phenomenon that occurs on a truly macroscopic scale, has attracted intense interest since its discovery in 1980 and has helped elucidate many important aspects of quantum physics. It has also led to the establishment of a new metrological standard, the resistance quantum. Disappointingly, however, the QHE has been observed only at liquid-helium temperatures. We show that in graphene, in a single atomic layer of carbon, the QHE can be measured reliably even at room temperature, which makes possible QHE resistance standards becoming available to a broader community, outside a few national institutions.
Occupational exposure to particulate air pollution and mortality due to ischaemic heart disease and cerebrovascular disease
Authors: Torén Kjell , Bergdahl Ingvar A , Nilsson Tohr , Järvholm Bengt
Published: February 2007

Objectives:A growing number of epidemiological studies are showing that ambient exposure to particulate matter air pollution is a risk factor for cardiovascular disease; however, whether occupational exposure increases this risk is not clear. The aim of the present study was to examine whether occupational exposure to particulate air pollution increases the risk for ischaemic heart disease and cerebrovascular disease.

Methods:The study population was a cohort of 176 309 occupationally exposed Swedish male construction workers and 71 778 unexposed male construction workers. The definition of exposure to inorganic dust (asbestos, man-made mineral fibres, dust from cement, concrete and quartz), wood dust, fumes (metal fumes, asphalt fumes and diesel exhaust) and gases and irritants (organic solvents and reactive chemicals) was based on a job-exposure matrix with focus on exposure in the mid-1970s. The cohort was followed from 1971 to 2002 with regard to mortality to ischaemic heart disease and cerebrovascular disease. Relative risks (RR) were obtained by the person-years method and from Poisson regression models adjusting for baseline values of blood pressure, body mass index, age and smoking habits.

Results:Any occupational particulate air pollution was associated with an increased risk for ischemic heart disease (RR 1.13, 95% CI 1.07 to 1.19), but there was no increased risk for cerebrovascular disease (RR 0.97, 95% CI 0.88 to 1.07). There was an increased risk for ischaemic heart disease and exposure to inorganic dust (RR 1.07, 95% CI 1.03 to 1.12) and exposure to fumes (RR 1.05, 95% CI 1.00 to 1.10), especially diesel exhaust (RR 1.18, 95% CI 1.13 to 1.24). There was no significantly increased risk for cerebrovascular disease and exposure to inorganic dust, fumes or wood dust.

Conclusions:Occupational exposure to particulate air pollution, especially diesel exhaust, among construction workers increases the risk for ischaemic heart disease.
Rhinitis and asthma symptoms in non-domestic cleaners from the São Paulo metropolitan area, Brazil
Authors: de Fátima Maçãira Elayne , Algranti Eduardo , Medina Coeli Mendonça Elizabete , Antônio Bussacos Marco
Published: February 2007

Background:Exposure to cleaning products has frequently been reported as a symptom trigger by workers with work-related asthma diagnosed in workers’ health clinics in the city of São Paulo, Brazil.

Objectives:To estimate rhinitis and asthma symptoms prevalence and to analyse associated risk factors.

Method:A respiratory symptoms questionnaire (Medical Research Council 1976) and the International Study of Asthma and Allergies in Childhood questionnaire were applied to 341 cleaners working in the city of São Paulo, along with obtaining full occupational histories, skin prick tests and spirometry. Timing their symptoms onset in relation to occupational history allowed estimation of work-related asthma and/or rhinitis. Risk factors related to selected outcomes were analysed by logistic regression.

Results:11% and 35% of the cleaners had asthma and rhinitis, respectively. The risk of work-related asthma/rhinitis increased with years of employment in non-domestic cleaning (OR 1.09, 95% CI 1.00 to 1.18, >0.92–3 years; OR 1.28, 95% CI 1.01 to 1.63, >3–6.5 years; OR 1.71, 95% CI 1.02 to 2.89, >6.5 years). Atopy was associated with asthma and rhinitis (OR 2.91, 95% CI 1.36 to 6.71; OR 2.06, 95% CI 1.28 to 3.35, respectively). There was a higher risk of rhinitis in women (OR 2.07, 95% CI 1.20 to 3.70).

Conclusions:Cleaning workers are at risk of contracting work-related asthma and/or rhinitis, and the risk increases with years of employment in non-domestic cleaning. Women present higher risk of rhinitis than men.
The management of poor performance
Authors: Mayberry John F
Published: February 2007

Identification of poor performance is in an integral part of government policy. The suggested approach for the identification of such problems, advocated by the General Medical Council, is that of appraisal. However, traditionally, there has been a reluctance to deal with poor performers, as all doctors have made mistakes and are usually only too ready to forgive and be non-critical of colleagues. The problems are widespread, and 6% of the senior hospital workforce in any 5-year period may have problems.
Complete occlusion of extracranial internal carotid artery: clinical features, pathophysiology, diagnosis and management
Authors: Thanvi Bhomraj , Robinson Tom
Published: February 2007

A complete occlusion of the internal carotid artery (ICA) is an important cause of cerebrovascular disease. A never-symptomatic ICA occlusion has a relatively benign course, whereas symptomatic occlusion increases future risk of strokes. Ultrasonography, magnetic resonance imaging and contrast angiography are useful diagnostic tests, and functional imaging of the brain (eg, with positron emission tomography) helps to understand haemodynamic factors involved in the pathophysiology of brain ischaemia. Recently, there has been a resurgence of interest in the role of extracranial–intracranial bypass surgery for the treatment of completely occluded ICA. With advances in the measurement of cerebral haemodynamics, it may be possible to identify high-risk patients who could benefit from the bypass surgery.
Mycoplasma pneumoniae and its role in asthma
Authors: Nisar Nazima , Guleria Randeep , Kumar Sanjay , Chand Chawla Tirlok , Ranjan Biswas Nihar
Published: February 2007

Mycoplasma pneumoniae (M pneumoniae), primarily recognised as a causative agent of community-acquired pneumonia has recently been linked to asthma. An infection with M pneumoniae may precede the onset of asthma or exacerbate asthma symptoms. Chronic infection with M pneumoniae has been suspected to play a part in some patients with asthma. The role of immunoglobulin E-related hypersensitivity and induction of T helper type 2 immune response leading to inflammatory response in M pneumoniae-infected patients with asthma have also been proposed. Use of macrolides in reducing asthma symptoms only in M pneumoniae-infected patients supports the use of macrolides in patients with asthma having M pneumoniae infection. As macrolides are both antimicrobial and anti-inflammatory drugs, the therapeutic role of their biphasic nature in reducing asthma symptoms needs further attention in clinical research.
Impact of early biliary complications in liver transplantation in the presence or absence of a T-tube: a Chinese transplant centre experience
Authors: Li Tang , Chen Zhi-Shui , Zeng Fan-Jun , Ming Chang-Sheng , Zhang Wei-Jie , Liu Dun-Gui , Jiang Ji-Ping , Du Dun-Feng , Klaus Chen Zhong-Hua
Published: February 2007

Background

Biliary complications continue to be an important determinant of the recipient's survival rate after orthotopic liver transplantation (OLT). The objective of this study was to evaluate the incidence of early biliary complications in OLT in the presence or absence of a T-tube.

Methods

This retrospective study, based on inpatient data, focused on the relationship between T-tube placement and early biliary complications of 84 patients after OLT, from November 2002 to June 2005. Patients were divided into two groups based on whether or not a T-tube was used following bile duct reconstruction: T-tube group (group I, n = 33); non-T-tube group (group II, n = 51).

Results

45.2% of OLT recipients had a malignant neoplasm. There were no significant differences in the demographic characteristics or operation data between the two groups. Overall, early biliary tract complications developed in 19.0% (16/84) of patients. The rate of early biliary complications was 30.3% (10/33) and 11.8% (6/51) in groups I II, respectively (p = 0.035). Biliary complications which were directly caused by T-tube placement occurred in 12.1% (4/33) of patients in group I. Overall, the percentage of malignant neoplasms, chronic viral cirrhosis, fulminant liver failure and other primary disease recipients with early biliary complications were 6.2%, 37.5%, 43.8% and 12.5%, respectively.

Conclusion

This study suggests that the use of a T-tube in Chinese patients undergoing OLT causes a higher incidence of early biliary complications. Most of the early biliary complications occurred in chronic viral cirrhosis and fulminant liver failure recipients.
Medical treatment of benign prostatic hyperplasia
Authors: Connolly Stephen S , Fitzpatrick John M
Published: February 2007

Pharmaceutical preparations are commonly used for benign prostate hyperplasia. This article reviews the current understanding of the natural history of the condition and the literature regarding medical treatment.
Dietary habits of young people attending secondary schools serving a multiethnic, inner-city community in the UK
Authors: Stone Margaret A , Bankart John , Sinfield Paul , Talbot Diane , Farooqi Azhar , Davies Melanie J , Khunti Kamlesh
Published: February 2007

Background

Childhood obesity is an escalating health concern with important implications, including increased risk of type 2 diabetes and cardiovascular disease. Although South Asians in the UK have an increased risk of developing these conditions, detailed studies on their lifestyles including the dietary habits of young people are scarce.

Methods

As part of an action research project, a food intake questionnaire was used to survey the dietary habits of 11–15-year olds attending five inner-city schools serving a predominantly South Asian population. Food choices were considered in the overall sample and in South Asians compared with white Europeans.

Results

3418 (72% of registered pupils) responses were obtained. A subset of 3018 pupils could be categorised as either South Asian (86%) or white European (14%). Around one fifth of pupils started the school day without eating anything. Responses indicated high consumption of “negative” foods such as sweets, including Asian sweets (63%), but lower rates for “positive” foods such as vegetables (34%). In the full sample, 26% said they had consumed more than one can of sugar-sweetened fizzy drink and 17% reported eating more than one packet of full-fat crisps on the previous day. Poor dietary habits were indicated in both South Asian and white European pupils.

Conclusions

Our large-scale survey confirmed poor dietary habits in secondary school pupils from a multiethnic community. Urgent efforts are needed to find ways of encouraging healthy lifestyles, particularly in populations with a high risk of developing cardiovascular disease and type 2 diabetes.