bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of Cardiac Output with Indocyanine Green Transcutaneous Fluorescence Dilution Technique
Authors: Maarek Jean-Michel I. , Holschneider Daniel P. , Harimoto Juji , Yang Jun , Scremin Oscar U. , Rubinstein Eduardo H. 
Published: May 2004

Background
Cardiac output is an essential parameter for the hemodynamic assessment of patients with cardiovascular disease. The authors tested in an animal model the feasibility of measuring cardiac output by transcutaneous fluorescence monitoring of an intravenous bolus injection of indocyanine green.

Methods
Fluorescence dilution cardiac output was measured in 10 anesthetized rabbits and compared with cardiac output measured with a pulmonary thermodilution catheter and to aortic velocity measured by Doppler ultrasound. Indocyanine green fluorescence was excited with a near-infrared laser and measured with an optical probe positioned on the central ear artery. Measurements were obtained during baseline conditions as well as during short-term decreases and increases of the cardiac output.

Results
The fluorescence of circulating indocyanine green detected transcutaneously varied proportionally to that of arterial blood samples, which allowed for calibration in terms of blood concentration of indocyanine green. Average values of fluorescence dilution cardiac output and thermodilution cardiac output measured in baseline conditions were 412 (+/- 13) and 366 (+/- 11) ml/min, respectively. Fluorescence dilution cardiac output showed a close, one-to-one linear relation with thermodilution cardiac output in each animal and in the pooled data from all animals (slope = 0.95 x 0.03; R = 0.94). Fluorescence dilution cardiac output overestimated thermodilution cardiac output by an average of 46 (+/- 6) ml/min during baseline conditions. Fluorescence dilution cardiac output was tightly correlated with aortic velocity.

Conclusions
The proposed technique yielded accurate estimates of the cardiac output in experimental animals. This study should provide an initial framework for clinical testing of this new minimally invasive method for measuring cardiac output.
Epidural Catheter Penetration of Human Dural Tissue
Authors: Angle Pamela J. , Kronberg Jean E. , Thompson Dorothy E. , Duffin James , Faure Peter , Balasubramaniam Shan , Szalai John Paul , Cromwell Susan 
Published: May 2004

Background
Factors contributing to subarachnoid catheter passage after epidural placement are not well understood. This study explored mechanisms that might explain its occurrence.

Methods
Human cadaveric dura was mounted on a model and pressurized to physiologic levels. In a standardized fashion, a 20-gauge Portex three-port, closed end (nonflexible) tip catheter was passed through an epidural needle mounted on a micromanipulator at a 90 degree angle, attempting to penetrate dura with the catheter. Attempts then followed with a 19-gauge Arrow Flex Tip Plus single-port catheter. Subarachnoid catheter passage was compared in (1) intact dura, (2) clinically occult versus obvious epidural needle punctures, and (3) single 25-gauge Whitacre spinal needle punctures after combined spinal-epidural placement.

Results
Neither catheter penetrated intact dura: Portex, 0 of 300 attempts (0.0000; 95% confidence interval [CI]: 0.0000, 0.0158); Arrow, 0 of 300 attempts (0.0000; 95% CI: 0.0000, 0.0158). In clinically occult epidural needle punctures, the 20-gauge Portex catheter penetrated 1 of 3 specimens in 1 of 14 attempts (0.0714; 95% CI: 0.0021, 0.3583). The 19-gauge Arrow did not pass (0 of 15 attempts, 0.0000; 95% CI: 0.0000, 0.2535). In clinically obvious epidural needle punctures, the Portex passed in 6 of 33 attempts (0.1818; 95% CI: 0.0760, 0.3608) and the Arrow passed in 1 of 35 attempts (0.0286; 95% CI: 0.0012, 0.1662). Neither catheter passed through a single 25-gauge spinal needle puncture after an uncomplicated combined spinal-epidural: Portex, 0 of 90 attempts (0.0000; 95% CI: 0.0000, 0.0510); Arrow, 0 of 90 attempts (0.0000; 95% CI: 0.0000, 0.0510).

Conclusions
Catheter passage is unlikely in the presence of intact dura or after an uncomplicated combined spinal-epidural. Unintentional subarachnoid passage suggests dural damage with the epidural needle.
Amitriptyline Neurotoxicity
Authors: Estebe Jean-Pierre , Myers Robert R. 
Published: May 2004

Background
Amitriptyline is a tricyclic antidepressant drug used systemically for the management of neuropathic pain. Antidepressants, as a class of drugs with direct neurologic actions, are becoming widely used for the management of chronic pain, although their mechanisms are not entirely understood. Amitriptyline exerts potent effects on reuptake of norepinephrine and serotonin and blocks alpha 2A adrenoreceptors and N-methyl-D-aspartate receptors. Because amitriptyline is also a particularly potent blocker of sodium channels and voltage-gated potassium and calcium channels, it has been recommended as a long-acting local anesthetic agent. Unfortunately, amitriptyline has significant toxic side effects in the central nervous system and cardiovascular system that are dose-related to its systemic administration. Therefore, before amitriptyline can be used clinically as a local anesthetic agent, it should be thoroughly explored with respect to its direct neurotoxic effect in the peripheral nervous system.

Methods
The left sciatic nerve of Sprague-Dawley rats (12/ group) received a single topical amitriptyline dose of 0.625, 1.25, 2.5, or 5 mg; a saline group (n = 2) was used as control. Neuropathologic evaluations were conducted in separate animals (n = 4) 1, 3, and 7 days later.

Results
Amitriptyline topically applied in vivo to rat sciatic nerve causes a dose-related neurotoxic effect. Drug doses of 0.625-5 mg all caused Wallerian degeneration of peripheral nerve fibers, with the number of affected fibers and the severity of the injury directly related to the dose.

Conclusion
Because the effective local anesthetic dose is within this dose range, the authors strongly recommend that amitriptyline not be used as a local anesthetic agent.
Electrical Nerve Localization
Authors: Hadzic Admir , Vloka Jerry D. , Claudio Richard E. , Hadzic Nihad , Thys Daniel M. , Santos Alan C. 
Published: May 2004

Background
Recommendations regarding the technical aspects of nerve stimulator-assisted nerve localization are conflicting. The objectives of this study were to determine whether the placement of the cutaneous electrode affects nerve stimulation and to determine the duration and intensity of an electrical stimulus that allows nerve stimulation with minimal discomfort.

Methods
Ten healthy volunteers underwent an interscalene and a femoral nerve block. After obtaining a clearly visible motor response of the biceps (interscalene) and quadriceps (femoral) muscles at the minimal current (0.1 ms, 2 Hz), the position of the cutaneous electrode was varied. Next, the duration of the stimulating current was set at 0.05, 0.1, 0.3, 0.5, or 1.0 ms, in random order. Intensity of the motor response and discomfort on stimulation were recorded.

Results
The minimal current at which a visible motor response was obtained was 0.32 +/- 0.1 mA (0.23-0.38 mA) for the inter-scalene block and 0.29 +/- 0.1 mA (0.15-0.4 mA) for the femoral block. Changing the position of the return electrodes did not result in any change in the grade of the motor response or in the current required to maintain it. Currents of longer duration caused discomfort and more forceful contraction at a lower current intensity as compared with currents of shorter duration (P < 0.01). When the current was adjusted to maintain the same visible motor response, there was no significant discomfort among studied current durations.

Conclusion
Site of placement of the cutaneous electrode is not important when constant current nerve stimulators are used during nerve localization in regional anesthesia. There is an inverse relation between the current required to obtain a visible motor response and current duration. Selecting a current duration between 0.05 and 1.0 ms to specifically stimulate sensory or motor components of a mixed nerve does not seem to be important in clinical practice.
Low Doses of Fentanyl Block Central Sensitization in the Rat Spinal Cord In Vivo
Authors: Benrath Justus , Brechtel Christina , Martin Eike , Sandkühler Jürgen 
Published: May 2004

Background
mu-Opioid receptor agonists are strong analgesics. However, their usefulness for preemptive analgesia is controversial. The authors tested antinociceptive and preemptive properties of fentanyl as a mu-opioid receptor agonist in a model of spinal nociception in vivo.

Methods
C fiber-evoked potentials were recorded in the superficial laminae I-II of the rat lumbar spinal cord with glass microelectrodes in response to electrical stimulation of the sciatic nerve. High-frequency stimulation was applied on the sciatic nerve to induce long-term potentiation of C fiber-evoked field potentials, a form of central sensitization. To test the effect of fentanyl on acute nociception, fentanyl was infused intravenously at increasing doses (6-192 microg.kg(-1).h(-1)). One hour after start of infusion, high-frequency stimulation was applied to evaluate effects of fentanyl on the induction of long-term potentiation.

Results
In the absence of fentanyl, high-frequency stimulation potentiated C fiber-evoked field potentials to 149 +/-12% of controls (mean +/-SEM; n = 6) for at least 1 h. Increasing doses of fentanyl led to a significant reduction of C fiber-evoked potentials in a dose-dependent manner. The induction of long-term potentiation was blocked by low doses of fentanyl (infusion 12-48 microg.kg(1).h(-1)). At high doses, fentanyl did not block the induction of long-term potentiation (infusion 96-192 microg.kg(-1).h(-1)).

Conclusions
: Low doses of fentanyl block the synaptic form of central sensitization in the rat spinal cord in vivo, but higher doses do not have this effect.
Incorporation of the fluorescent amino acid 7‐azatryptophan into the core domain 1–47 of hirudin as a probe of hirudin folding and thrombin recognition
Authors: De Filippis Vincenzo , De Boni Silvia , De Dea Elisa , Dalzoppo Daniele , Grandi Claudio , Fontana Angelo 
Published: May 2004

Abstract7‐Azatryptophan (AW), a noncoded isostere of tryptophan (W), possesses interesting spectral properties. In particular, the presence of a nitrogen atom at position 7 in the indolyl nucleus of AW results in a red shift of the absorption maximum and fluorescence emission by 10 and 46 nm, respectively, compared to W. In the present work, we report the chemical synthesis and the conformational and functional characterization of an analog (denoted as Y3AW) of the N‐terminal domain 1–47 of hirudin, a highly potent thrombin inhibitor, in which Tyr 3 has been replaced by AW. The results obtained were compared with those of the cooresponding Y3W analog. We found that the replacement W → AW reduces affinity for thrombin by 10‐fold, likely because of the lower hydrophobicity of AW compared with that of W. Measurements of the resonance energy transfer effect, which was observed between Tyr13 and the amino acid at position 3 upon disulfide‐coupled folding, demonstrate that AW behaves as a better energy acceptor than W for studying protein renaturation. The interaction of Y3AW with thrombin was studied by exciting the sample at 320 nm and recording the change in fluorescence of Y3AW on binding to the enzyme. Our results indicate that the fluorescence of AW of hirudin 1–47 in the Y3AW–thrombin complex is strongly quenched, possibly because of the presence of two structural water molecules at the hirudin–thrombin interface that can promote the nonradiative decay of AW in the excited state. The data herein reported demonstrate that the incorporation of AW can be of broad applicability in the study of protein folding and protein–protein interaction.
Identification of the N‐glycosylation sites on glutamate carboxypeptidase II necessary for proteolytic activity
Authors: Barinka Cyril , Šácha Pavel , Sklenář Jan , Man Petr , Bezouška Karel , Slusher Barbara S. , Konvalinka Jan 
Published: May 2004

AbstractGlutamate carboxypeptidase II (GCPII) is a membrane peptidase expressed in the prostate, central and peripheral nervous system, kidney, small intestine, and tumor‐associated neovasculature. The GCPII form expressed in the central nervous system, termed NAALADase, is responsible for the cleavage of N‐acetylL‐aspartyl‐L‐glutamate (NAAG) yielding free glutamate in the synaptic cleft, and is implicated in various pathologic conditions associated with glutamate excitotoxicity. The prostate form of GCPII, termed prostate‐specific membrane antigen (PSMA), is up‐regulated in cancer and used as an effective prostate cancer marker. Little is known about the structure of this important pharmaceutical target. As a type II membrane protein, GCPII is heavily glycosylated. In this paper we show that N‐glycosylation is vital for proper folding and subsequent secretion of human GCPII. Analysis of the predicted N‐glycosylation sites also provides evidence that these sites are critical for GCPII carboxypeptidase activity. We confirm that all predicted N‐glycosylation sites are occupied by an oligosaccharide moiety and show that glycosylation at sites distant from the putative catalytic domain is critical for the NAAG‐hydrolyzing activity of GCPII calling the validity of previously described structural models of GCPII into question.
New enzymes from environmental cassette arrays: Functional attributes of a phosphotransferase and an RNA‐methyltransferase
Authors: Nield Blair S. , Willows Robert D. , Torda Andrew E. , Gillings Michael R. , Holmes Andrew J. , Nevalainen K.M. Helena , Stokes H.W. , Mabbutt Bridget C. 
Published: May 2004

AbstractBy targeting gene cassettes by polymerase chain reaction (PCR) directly from environmentally derived DNA, we are able to amplify entire open reading frames (ORFs) independently of prior sequence knowledge. Approximately 10% of the mobile genes recovered by these means can be attributed to known protein families. Here we describe the characterization of two ORFs which show moderate homology to known proteins: (1) an aminoglycoside phosphotransferase displaying 25% sequence identity with APH(7″) from Streptomyces hygroscopicus, and (2) an RNA methyltransferase sharing 25%–28% identity with a group of recently defined bacterial RNA methyltransferases distinct from the SpoU enzyme family. Our novel genes were expressed as recombinant products and assayed for appropriate enzyme activity. The aminoglycoside phosphotransferase displayed ATPase activity, consistent with the presence of characteristic Mg2+‐binding residues. Unlike related APH(4) or APH(7″) enzymes, however, this activity was not enhanced by hygromycin B or kanamycin, suggesting the normal substrate to be a different aminoglycoside. The RNA methyltransferase contains sequence motifs of the RNA methyltransferase superfamily, and our recombinant version showed methyltransferase activity with RNA. Our data confirm that gene cassettes present in the environment encode folded enzymes with novel sequence variation and demonstrable catalytic activity. Our PCR approach (cassette PCR) may be used to identify a diverse range of ORFs from any environmental sample, as well as to directly access the gene pool found in mobile gene cassettes commonly associated with integrons. This gene pool can be accessed from both cultured and uncultured microbial samples as a source of new enzymes and proteins.
Theoretical study of interaction of winter flounder antifreeze protein with ice
Authors: Jorov Alexander , Zhorov Boris S. , Yang Daniel S.C. 
Published: May 2004

AbstractAntifreeze proteins (AFPs) are synthesized by various organisms to enable their cells to survive subzero environment. These proteins bind to small ice crystals and inhibit their growth, which if left uncontrolled would be fatal to cells. The crystal structures of a number of AFPs have been determined; however, crystallographic analysis of AFP–ice complex is nearly impossible. Molecular modeling studies of AFPs' interaction with ice surface is therefore invaluable. Early models of AFP–ice interaction suggested H‐bond as the primary driving force behind such interaction. Recent experimental evidence, however, suggested that hydrophobic interactions could be the main contributor to AFP–ice association. All computational studies published to date were carried out to verify the H‐bond model, and no works attempting to verify the hydrophobic interaction model have been published. In this work, we Monte Carlo–minimized complexes of several AFPs with ice taking into account nonbonded interactions, H‐bonds, and the hydration potential for proteins. Parameters of the hydration potential for ice were developed with the assumption that the free energy of the water–ice association should be close to zero at equilibrium melting temperature. Our calculations demonstrate that desolvation of hydrophobic groups in the AFPs upon their binding to the grooves at the ice surface is indeed the major stabilizing contributor to the free energy of AFP–ice binding. This study is consistent with available structural and mutation data on AFPs. In particular, it explains the paradoxical finding that substitution of Thr residues with Val does not affect the potency of winter flounder AFP whereas substitution with Ser abolished its antifreeze activity.
Heterodimers of wild‐type and subunit interface mutant enzymes of glutathione S‐transferase A1–1: Interactive or independent active sites?
Authors: Vargo Melissa A. , Colman Roberta F. 
Published: May 2004

AbstractHeterodimers of rat glutathione S‐transferase A1–1 were formed using one wild‐type subunit and one subunit with a mutation at the interface to evaluate whether the subunits are interactive or independent. Within the subunit interface, we are considering two regions of interactions: one region consists of a “hydrophobic ball and socket” with Phe 52 from one subunit as the ball and Phe 136 from the second subunit as one of the socket residues. The second region of interaction consists of Arg 69 and Glu 97 from both subunits. The heterodimers were formed after incubation in 1,6‐hexanediol. Because one subunit in each pair had a His‐tag, the heterodimers were purified using a nickel‐nitrilotriacetic acid column. The specific activities of the heterodimer were compared with those of the two homodimers to determine whether the less active, mutant subunit communicates with the other subunit. Two of the heterodimers, wild type/R69E‐His and wild type/E97Q‐His, displayed specific activities much lower than that expected for independent active sites; in these cases, there are new close repulsive interactions and the low activity of one subunit is communicated to the neighboring subunit. In contrast, the other two heterodimers, wild type/R69Q‐His and F136A/wild type‐His, exhibited specific activities similar to those expected for independent active sites; in these heterodimers, the closest interaction is not repulsive or occurs over a much longer distance and the subunits act independently. We conclude that whether the subunits interact or are independent depends on the nature of the interactions at the subunit interface.
Why Deliberate? The Encounter Between Deliberation and New Public Managers
Authors: Parkinson John 
Published: May 2004

A number of organizations in Britain's National Health Service (NHS) have been experimenting with ‘deliberative’ techniques of citizen involvement, techniques that were designed with democratic imperatives in mind. However, political practices are moulded by their institutional settings and the goals of their proponents, so it is unlikely that they have been left ‘pure’ following their encounter with public management imperatives.This paper offers an explanation for the interest in deliberative processes in the NHS by comparing deliberative and public management imperatives, as well as discussing more case‐specific motivations, drawing on interviews with health policy actors between May and July 2001. I then use those insights to highlight gaps between the deliberative ideal and deliberative practice, showing what has been gained and what has been lost in the encounter between deliberative democracy and new public managers.
Reshaping Public Administration: The Spanish Experience Compared to the UK
Authors: Torres LourDes , Pina Vicente 
Published: May 2004

This paper analyses the nature and extent of the policies of modernizing Spanish public administration. Successive Spanish governments have been involved in modernizing public administration with the stress on customer focus, improving service delivery and implementing quality awards, service charts and information technologies.As a basis for assessing the reforms, we compare Spanish New Public Management (NPM) developments with the initiatives undertaken in the UK. The paper evaluates the usage of NPM concepts in the Spanish and UK experiences and cultural differences based on public and common law traditions respectively, locating these reforms in a comparative context. We focus on why similar concepts and initiatives could provide such different results in each country and how the cultural and institutional features produce differences in the way that NPM postulates are defined, implemented, monitored and evaluated. The answer is probably rooted in the context in which the initiatives have been developing.
Cholecystokinin blockade alters the systemic immune response in rats with acute pancreatitis
Authors: De La Mano Ana Maria , Sevillano Sara , Manso Manuel Antonio , Pérez Martin , Dios Isabel de 
Published: May 2004

SummaryAcute pancreatitis (AP) is characterized by initial pancreatic injury resulting from the activation of digestive enzymes and, later, widespread inflammation to distant organs. The aim of this study was to study whether the time‐course of inflammatory events during AP induced by bile‐pancreatic duct obstruction (BPDO) varies after lowering the acinar enzyme content by L364,718 (0.1 mg/kg/day) administration over 7 days before inducing AP. Flow cytometric immunophenotyping was used to analyse the following at different AP stages: distribution of major circulating leucocyte subsets, activation state of circulating neutrophils and monocytes as reflected by CD11b expression and tumour necrosis factor‐α (TNF‐α) production and the contribution of T‐cell‐derived pro‐(TNF‐α) and anti‐(IL‐10) inflammatory mediators. TNF‐α plasma levels and neutrophil infiltration in pancreas and lung were also measured. At early BPDO times, L364,718 treatment partially inhibited leukocytosis and increase in peripheral blood neutrophils and monocytes as well as TNF‐α expression by monocytes. However, from 6 h onwards after BPDO, L364,718 treatment was unable to prevent either pancreatic and lung neutrophil infiltration or the release of TNF‐α from activated monocytes. By its action on circulating lymphocytes, L364,718 treatment enhanced the severity of the inflammatory response induced by BPDO. Peripheral blood lymphocytes were recruited from earlier BPDO times, and 12 h after BPDO, T cells displayed a significantly higher reserve of TNF‐α able to be released under stimulation but lower functional reserve of interleukin‐10 (IL‐10) than observed in untreated rats. It is concluded that lowering the acinar enzyme content through L364,718 treatment prevents earlier systemic immune events in BPDO‐induced AP. However, at the point of maximal injury, the inflammatory response became pronounced, largely due to the role played by activated T lymphocytes.