bluuebunny/crossref_metadata_2025 huggingface dataset:
Focal hypoxia of the obstructed rabbit bladder wall correlates with intermediate decompensation
Authors: Levin Robert M. , O'Connor Laura J. , Leggett Robert E. , Whitbeck Catherine , Chichester Paul
Published: February 2003

Aims

We showed that partial obstruction of the rabbit bladder outlet caused decreases in detrusor blood flow that were directly proportional to the level of decompensation present. Bladder decompensation is characterized by decreases in detrusor contractility, mitochondrial function, and sarco/endoplasmic reticulum calcium ATPase (SERCA) activity in obstructed rabbits. The current study was designed to create bladder decompensation and to relate its characteristic dysfunctions to the presence or absence of hypoxia in the obstructed rabbit bladder wall. Tissue hypoxia was visualized immunohistochemically after administration of a hypoxia probe in vivo.

Methods

Twelve New Zealand White rabbits were separated into two groups. The rabbits in group 1 received sham operations; the rabbits in group 2 received partial outlet obstructions by standard methods. Four weeks after surgery, each rabbit received an intraperitoneal injection of aqueous Hypoxyprobe‐1, which forms protein adducts in cells having O2 concentrations less than 14 μM. Two hours after injection, the rabbit was anesthetized and the bladder exposed through a midline incision. One full‐thickness bladder strip was cut and immediately placed in fixative for immunohistochemical recognition and visualization of Hypoxyprobe‐1–protein adducts. The remaining bladder was then excised, and three additional strips were cut for contractility studies. The remainder of the bladder was frozen for biochemical and slot‐blot analyses.

Results

Bladder weight was increased fourfold after obstruction, and significant contractile and biochemical dysfunctions were observed that indicated an intermediate level of decompensation. Immunohistochemical visualization revealed focal areas of moderate to severe hypoxia in the detrusor smooth muscle (SM) and subserosal regions of these bladders. No hypoxia was observed in the obstructed bladder mucosa, consistent with the absence of biochemical dysfunction in this compartment, or in unobstructed bladders. Slot‐blot analyses confirmed the presence of significant Hypoxyprobe‐1–protein adducts in the detrusor of the obstructed bladder, whereas none were present in the control bladder detrusors.

Conclusions

Partial outlet obstruction of rabbit bladders resulted in focal areas of moderate to severe hypoxia in the detrusor SM and subserosal regions concomitant with increased bladder mass, decreased contractile function, and selective metabolic dysfunctions of the SM consistent with an intermediate stage of decompensation. The metabolic characteristics of the normoxic mucosa were normal a were those of unobstructed bladders. Neurourol. Urodynam. 22:156–163, 2003. © 2003 Wiley‐Liss, Inc.
On the performance quality of repairable systems
Authors: Finkelstein M. S.
Published: February 2003

The quality of a system operation is characterized by decreases in time deterministic function or by a stochastic process with decreasing sample paths. Simple relations for the stationary characteristic of quality are derived in cases when the system is repairable after each failure. Methods of quality improvement are considered. The case of imperfect repair for a simplified setting is studied. Several examples are considered. Copyright © 2003 John Wiley & Sons, Ltd.
Testing for Reliability
Authors: O'Connor Patrick
Published: February 2003

This tutorial article describes the role of testing in the creation of reliable products. It is based upon parts of the author's book ‘Test Engineering’.Reproduced by permission of John Wiley & Sons, Ltd.

The book has a web page (www.pat‐oconnor.co.uk/testengineering.htm), which provides information on and links to test organizations, standards, suppliers of equipment and facilities, etc. Copyright © 2003 John Wiley & Sons, Ltd.
Ferromagnetic vs. nonmagnetic phases of 2‐D Wigner electron crystal
Authors: Rajeswarapalanichamy R. , Iyakutti K.
Published: February 2003

The ferromagnetic and nonmagnetic phases of 2‐D Wigner electron crystal are investigated using a localized representation for the electrons. The ground‐state energies of ferromagnetic and nonmagnetic phases of 2‐D Wigner electron crystal are computed in the range of rs = 10–200. The low density favorable for Wigner crystallization is found to be 2.85 × 1013 e cm−2 for ferromagnetic phase and 5.07 × 1013 e cm−2 for the nonmagnetic phase of 2‐D Wigner electron crystal. For the given structure, the ground‐state energies of ferromagnetic and nonmagnetic phases are compared. It is found that the energy of the ferromagnetic phase is less than that of the nonmagnetic phase of the 2‐D Wigner electron crystal. Also, the results are compared with various experimental and theoretical works and it is found that our results are in good agreement with the experimental and other theoretical results for the 2‐D Wigner electron crystal. The structure‐dependent Wannier functions, which give proper localized representation for Wigner electrons, are employed in the calculation. The role of correlation energy is suitably taken into account. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
The nature of middle school learners' science content understandings with the use of on‐line resources
Authors: Hoffman Joseph L. , Wu Hsin‐Kai , Krajcik Joseph S. , Soloway Elliot
Published: February 2003

Early research on using the World Wide Web indicated that middle school students did not explore much and used Web tools naively. In response to these challenges, an on‐line research engine, Artemis, was designed to provide a permanent workspace and allow students access to preselective on‐line resources. This study investigated the depth and accuracy of sixth‐grade students' content understandings as well as their use of search and assess strategies when they used on‐line resources via Artemis. Eight student pairs from two science classes experienced support from teachers and used scaffolded curriculum materials while completing four on‐line inquiry units during 9 months. Multiple sources of data were collected, including video recordings of students' computer activities and conversations, students' artifacts and on‐line postings, classroom and lab video recordings, and interview transcripts. Analyses of data showed that students constructed meaningful understandings through on‐line inquiry, although the accuracy and depth of their understandings varied. The findings suggest that students might develop accurate and in‐depth understandings if they use search and assess strategies appropriately, if resources are thoughtfully chosen, and if support from the learning environment is extensively provided. This research lends evidence to questions regarding the value of students engaging in on‐line inquiry. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 323–346, 2003
Beyond Species: Il’ya Ivanov and His Experiments on Cross-Breeding Humans with Anthropoid Apes
Authors: Rossiianov Kirill
Published: February 2003

Argument

I believe that some pollutions are used as analogies for expressing a general view of the social order.

Mary Douglas, Purity and Danger (Douglas 1966, 14)

The possibility of crossing humans with other anthropoid species has been discussed in fiction as well as in scientific literature during the twentieth century. Professor Il’ya Ivanov’s attempt to achieve this was crucial for the beginning of organized primate research in the Soviet Union, and remains one of the most interesting and controversial experiments that was ever done on non-human primates. The possibility of removing the boundary that separates humans from other animal species, apes in particular, is loaded with important political meaning and violates cultural and ethical taboos. The history of Ivanov’s scientific experiment thus helps to reveal some of the twentieth-century’s important cultural conventions and hidden assumptions about human nature, species, and social hierarchy.
Biliary inorganic phosphate as a tool for assessing cold preservation-reperfusion injury: A study in the isolated perfused rat liver model
Authors: Almada Luciana L. , Scandizzi Angel L. , Guibert Edgardo E. , Furno Graciela , Rodriguez Joaquin V.
Published: February 2003

Ischemia-reperfusion injury is a major cause of early graft dysfunction after liver transplantation. The bile flow has been suggested as an index of ischemic damage, and severely impaired bile flow seems to be predictive of poor survival in experimental studies. Looking for injury markers, biliary inorganic phosphate has the potential of being a useful endogenous marker of diminished hepatobiliary function because this anion is excreted in the bile by a paracellular pathway and it can detect changes in permeability. The goal of this study was to evaluate the effects of cold preservation-reperfusion of the liver on bile flow and bile inorganic phosphate and their relationship with storage-related graft failure. The isolated and perfused rat liver was used to evaluate the injury for ischemia-reperfusion. The intrahepatic resistance, lactate dehydrogenase release, and potassium and biliary inorganic phosphate concentration were used to estimate viability and function of freshly isolated or cold-preserved livers. The intrahepatic resistance and the bile flow were consistent and significantly decreased throughout the perfusion time in relation to the increment in storage. Inorganic phosphate is more concentrated in bile from preserved livers, showing an alteration in paracellular pathway, confirmed by the biliary excretion of horseradish peroxidase. After preservation, concentration and excretion of the paracellular marker were increased during the first peak. The second peak appears earlier in preserved livers (10 minutes) with a different shape but without changes in concentration. In conclusion, inorganic phosphate in bile shows changes in paracellular permeability as occurs in livers after 48 hours of cold preservation.
Genetic variation in cyclooxygenase 1: Effects on response to aspirin
Authors: Halushka Marc K. , Walker Linda P. , Halushka Perry V.
Published: February 2003

Background

A critical clinical application of the Human Genome Project is to identify functional variation in genes related to disease or responses to xenobiotics. This study moved toward that goal by combining polymorphism detection with functional assays for the therapeutic target gene cyclooxygenase 1 (COX‐1). Cyclooxygenase 1 (prostaglandin endoperoxide G/H synthase [PTGS1]) catalyzes the metabolism of arachidonic acid to prostaglandin H2, which is subsequently metabolized to thromboxane A2.

Methods

Thirty‐eight healthy participants were enrolled in this study to correlate functional and genetic variation of cyclooxygenase 1. Arachidonic acid, with and without aspirin (acetylsalicylic acid) and ethanol pretreatment, was used to stimulate the formation of prostaglandin H2, measured as prostaglandin F2α (PGF2α), in human platelets. The cyclooxygenase 1 complementary deoxyribonucleic acid coding sequence and genomic deoxyribonucleic acid upstream from the cyclooxygenase 1 transcription start site (2.9 kilobases) were sequenced in 38 individuals, with 9 single‐nucleotide polymorphisms identified.

Results

Two single‐nucleotide polymorphisms, A‐842G and C50T, were in complete linkage disequilibrium. Participants who were heterozygous for the A‐842G/C50T haplotype showed significantly (P = .01) greater inhibition of prostaglandin H2 formation by acetylsalicylic acid (30 μmol/L) compared with common allele homozygotes.

Conclusions

The discovery of a functional single‐nucleotide polymorphism in the cyclooxygenase 1 locus may ultimately improve the safe and effective use of acetylsalicylic acid by better tailoring of dosage with an individual's genetic variation.

Clinical Pharmacology & Therapeutics (2003) 73, 122–130; doi: 10.1067/mcp.2003.1
Dipyridamole enhances digoxin bioavailability via P‐glycoprotein inhibition
Authors: Verstuyft Céline , Strabach Soraya , El Morabet Hakima , Kerb Reinhold , Brinkmann Ulrich , Dubert Liliane , Jaillon Patrice , Funck‐Brentano Christian , Trugnan Germain , Becquemont Laurent
Published: February 2003

Background

On the basis of in vitro studies indicating that dipyridamole is an inhibitor for the MDR1 efflux membrane transporter P‐glycoprotein, we postulated that dipyridamole could increase the bioavailability of digoxin, a P‐glycoprotein substrate.

Objectives

The main objective was to determine whether dipyridamole alters the bioavailability of digoxin. The secondary objective was to determine whether the magnitude of the pharmacokinetic interaction was influenced by MDR1 genetic polymorphism in exon 26 (C3435T).

Material and methods

(1) The effect of dipyridamole on in vitro P‐glycoprotein‐mediated, polarized transport of tritium‐labeled digoxin was investigated in Caco‐2 cell monolayers. (2) Twelve healthy volunteers participated in this open, randomized, 2‐period crossover study, in which the effects of dipyridamole (300 mg/d for 3 days) versus placebo on the pharmacokinetics of a single oral dose of digoxin (0.5 mg) were compared. MDR1 genotyping (exon 26, C3435T) was determined before the study to include 6 homozygous CC and 6 homozygous TT subjects.

Results

Dipyridamole inhibited [3H]digoxin transport in Caco‐2 cells with a 50% inhibitory concentration value of 1.5 ± 1.5 μmol/L. We observed a 20% and 13% increase in digoxin area under the plasma concentration‐time curve (AUC) from 0 to 4 hours and AUC from 0 to 24 hours (P < .05), respectively, during dipyridamole administration, which was consecutive to an increase in digoxin absorption. Digoxin AUC from 0 to 4 hours and AUC from 0 to 24 hours were significantly higher among subjects harboring the TT compared with the CC MDR1 genotype: 7.5 ± 1.2 ng × h × mL−1 versus 6.1 ± 0.8 ng × h × mL−1 and 20.2 ± 2.1 ng × h × mL−1 versus 16.8 ± 1.7 ng × h × mL−1, respectively (P < .05). Digoxin pharmacokinetic modifications during the dipyridamole period were similar in both genotypes.

Conclusion

Dipyridamole is an in vitro and in vivo P‐glycoprotein inhibitor that increases intestinal digoxin absorption and digoxin plasma concentrations. In light of the modest changes in digoxin pharmacokinetics in the presence of dipyridamole, this drug interaction is probably clinically irrelevant.

Clinical Pharmacology & Therapeutics (2003) 73, 51–60; doi: 10.1067/mcp.2003.8
Functional Characterisation of the Volume‐Sensitive Anion Channel in Rat Pancreatic β‐Cells
Authors: Best L. , Speake T. , Brown P. D.
Published: February 2003

The whole‐cell and perforated patch configurations of the patch‐clamp technique were used to characterise the volume‐sensitive anion channel in rat pancreatic β‐cells. The channel showed high permeability (P) relative to Cl− to extracellular monovalent organic anions (PSCN/PCll= 1.73, Pacetate/PCll= 0.39, Plactate/PCll= 0.38, Pacetoacetate/PCll= 0.32, Pglutamate/PCll= 0.28) but was less permeable to the divalent anion malate (Pmalate/PCll= 0.14). Channel activity was inhibited by a number of putative anion channel inhibitors, including extracellular ATP (10 mM), 1,9‐dideoxyforskolin (100 μM) and 4‐OH tamoxifen (10 μM). Inclusion of the catalytic subunit of protein kinase A in the pipette solution did not activate the volume‐sensitive anion channel in non‐swollen cells. Furthermore, addition of 8‐bromoadenosine 3′,5′‐cyclic monophosphate (8‐BrcAMP) or forskolin failed to activate the channel in intact cells under perforated patch conditions. Addition of phorbol 12,13‐dibutyrate (200 nM), either before or after cell swelling, also failed to affect channel activation. Our findings do not support the suggestion that the volume‐sensitive anion channel in pancreatic β‐cells can be activated by protein kinase A. Furthermore, the β‐cell channel does not appear to be subject to regulation via protein kinase C.
The Effects of Age and Hindlimb Supension on the Levels of Expression of the Myogenic Regulatory Factors Myod and Myogenin in Rat Fast and Slow Skeletal Muscles
Authors: Alway Stephen E. , Lowe Dawn A. , Chen Kuangjen D.
Published: February 2003

In this study we tested the hypothesis that, compared to young adult rats, senescent rats have a reduced ability to respond to muscle unloading. Unloading of the muscles was induced by hindlimb suspension (HS) of young adult and senescent rats for 21 days. Plantaris muscles from young adult rats had significantly higher levels of myogenin mRNA and protein (890% and 314%, respectively, P < 0.05) than plantaris muscles from senescent rats and also a higher MyoD mRNA level (280%, P < 0.05), but ageing did not increase MyoD protein levels. Although HS did not increase plantaris mRNA or protein levels of myogenin or MyoD in senescent rats (P = 0.22), myogenin mRNA and protein levels increased by 850% and 580% respectively, and MyoD mRNA and protein levels by 235% and 1600%, respectively in young adult rats (P < 0.05). Soleus muscles from senescent rats had 150% and 85% greater myogenin and MyoD mRNA levels, respectively (P < 0.05), than soleus muscles from young adult rats, whereas protein levels of myogenin were similar (P > 0.05) and MyoD protein levels were 60% lower in the muscle of senescent rats (P < 0.05). In young rats, soleus muscle mRNA levels of myogenin and MyoD were not altered by HS but myogenin protein levels decreased by 57% (P < 0.05) whereas MyoD protein levels increased by 187% (P < 0.05). In senescent rats, HS decreased soleus muscle myogenin mRNA and protein levels by 42% and 26% respectively (P < 0.05), but MyoD protein and mRNA levels were not changed. MRF4 levels were not affected by ageing in either muscle. These data suggest that ageing reduces the ability of fast muscles to increase myogenin protein levels, and prevents both fast and slow muscles from increasing MyoD protein levels during muscle unloading.
Method for Continuous Measurements of Renal Sympathetic Nerve Activity and Cardiovascular Function During Exercise in Rats
Authors: Miki Kenju , Kosho Atuko , Hayashida Yoshiaki
Published: February 2003

The sympathetic nervous system is believed to play a major role in regulating cardiovascular function during exercise. However, only a few direct measurements of sympathetic nervous activity during whole body dynamic exercise have been attempted. In the present study, we have established a method to allow routine measurement of renal sympathetic nerve activity (RSNA) and cardiovascular function during treadmill exercise in rats. We trained Wistar rats to run on the treadmill for a week before the surgery. At least 2 days before the experiment, electrodes for recording RSNA, electrocardiogram and electromyogram, and catheters for the measurements of systemic arterial and central venous pressures were implanted under aseptic conditions. Satisfactory signal to noise ratios were obtained in 80%, 60% and 40% of the group at 1‐3 days, 4‐7 days and 8‐10 days after the surgery, respectively. RSNA was successfully recorded without contamination by external noise during treadmill exercise. Treadmill exercise resulted in an abrupt increase in RSNA, by 82% at 0.5 min, and then reached a stable level of ∼40% during the period of 5‐30 min after the onset of treadmill exercise. This experimental model allows us to study the neural mechanisms involved in the regulation of cardiovascular function during dynamic exercise in rats.
Muscarinic Agonist‐Induced Non‐Granular and Granular Secretion of Amylase in the Parotid Gland of the Anaesthetized Rat
Authors: Ekström J.
Published: February 2003

The muscarinic agonist bethanechol was infused intravenously, under α‐ and β‐adrenoceptor blockade, in anaesthetized rats at various dose levels (5‐10, 20 and 40‐50 μg kg−1 min−1) over 30 min. The amount of saliva secreted from the parotid gland was dose dependent at 95, 202 and 737μl, respectively. The salivary amylase activity was approximately the same at the two lower doses (506 U and 448 U, respectively), while it was higher (1268 U) at the highest dose. In response to the highest dose, but not to the lower doses, the total parotid glandular amylase activity and the numerical density of parotid acinar secretory granules were lowered, by 25% and 22%, respectively. Thus, in the rat parotid gland, agonists such as bethanechol, which use Ca2+ as a second messenger, may release proteins not only by non‐granular mechanisms but also, and in contrast to the general belief, by granule exocytosis.
The Effect of Resistive Breathing on Leg Muscle Oxygenation Using Near‐Infrared Spectroscopy During Exercise in Men
Authors: Kowalchuk‡ John M. , Rossiter Harry B. , Ward Susan A. , Whipp Brian J.
Published: February 2003

The effect of added respiratory work on leg muscle oxygenation during constant‐load cycle ergometry was examined in six healthy adults. Exercise was initiated from a baseline of 20 W and increased to a power output corresponding to 90% of the estimated lactate threshold (moderate exercise) and to a power output yielding a tolerance limit of 11.8 min (± 1.4, S.D.) (heavy exercise). Ventilation and pulmonary gas exchange were measured breath‐by‐breath. Profiles of leg muscle oxygenation were determined throughout the protocol using near‐infrared (NIR) spectroscopy (Hamamatsu NIRO 500) with optodes aligned midway along the vastus lateralis of the dominant leg. Four conditions were tested: (i) control (Con) where the subjects breathed spontaneously throughout, (ii) controlled breathing (Con Br) where breathing frequency and tidal volume were matched to the Con profile, (iii) increased work of breathing (Resist Br) in which a resistance of 7 cmH2O l−1 s−1 was inserted into the mouthpiece assembly, and (iv) partial leg blood flow occlusion (Leg Occl), where muscle perfusion was reduced by inflating a pressure cuff (∼90 mmHg) around the upper right thigh. During Resist Br and Leg Occl, subjects controlled their breathing pattern to reproduce the ventilatory profile of Con. An ∼3 min period with respiratory resistance or pressure cuff was introduced ∼4 min after exercise onset. NIR spectroscopy data for reduced haemoglobin‐myoglobin (Δ[Hb]) were extracted from the continuous display at specific times prior to, during and after removal of the resistance or pressure cuff. While the Δ[Hb] increased during moderate‐ and heavy‐intensity exercise, there was no additional increase in Δ[Hb] with Resist Br. In contrast, Δ[Hb] increased further with Leg Occl, reflecting increased muscle O2 extraction during the period of reduced muscle blood flow. In conclusion, increasing the work of breathing did not increase leg muscle deoxygenation during heavy exercise. Assuming that leg muscle O2 consumption did not decrease, this implies that leg blood flow was not reduced consequent to a redistribution of flow away from the working leg muscle.
Replication and Transcription of Mammalian Mitochondrial Dna
Authors: Fernández‐Silva Patricio , Enriquez José A. , Montoya Julio
Published: February 2003

Mitochondria are subcellular organelles, devoted mainly to energy production in the form of ATP, that contain their own genetic system. Mitochondrial DNA codifies a small, but essential number of polypeptides of the oxidative phosphorylation system. The mammalian mitochondrial genome is an example of extreme economy showing a compact gene organization. The coding sequences for two ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs) and 13 polypeptides are contiguous and without introns. The tRNAs are regularly interspersed between the rRNA and protein‐coding genes, playing a crucial role in RNA maturation from the polycistronic transcripts. A single major non‐coding region, called the D‐loop region, contains the main regulatory sequences for transcription and replication initiation. This genetic organization has its precise correspondence in the mode of expression and distinctive structural features of the RNAs. The basic mechanisms of mitochondrial DNA transcription and replication and the main cis‐acting elements playing a role in both processes have been determined. Many trans‐acting factors involved in mitochondrial gene expression, including the RNA and DNA polymerases, have been cloned or identified. However, the regulatory mechanisms participating in mitochondrial gene expression are still poorly understood. The interest to complete this knowledge is increased by the involvement of mitochondria in human diseases, in basic processes such as heat production, Ca2+ homeostasis and apoptosis, and by their potential role in ageing and carcinogenesis.
Glucose Regulation of
Saccharomyces cerevisiae
Cell Cycle Genes
Authors: Newcomb Laura L. , Diderich Jasper A. , Slattery Matthew G. , Heideman Warren
Published: February 2003

Nutrient-limited
Saccharomyces cerevisiae
cells rapidly resume proliferative growth when transferred into glucose medium. This is preceded by a rapid increase in
CLN3
,
BCK2
, and
CDC28
mRNAs encoding cell cycle regulatory proteins that promote progress through Start. We have tested the ability of mutations in known glucose signaling pathways to block glucose induction of
CLN3
,
BCK2
, and
CDC28
. We find that loss of the Snf3 and Rgt2 glucose sensors does not block glucose induction, nor does deletion of
HXK2
, encoding the hexokinase isoenzyme involved in glucose repression signaling. Rapamycin blockade of the Tor nutrient sensing pathway does not block the glucose response. Addition of 2-deoxy glucose to the medium will not substitute for glucose. These results indicate that glucose metabolism generates the signal required for induction of
CLN3
,
BCK2
, and
CDC28
. In support of this conclusion, we find that addition of iodoacetate, an inhibitor of the glyceraldehyde-3-phosphate dehydrogenase step in yeast glycolysis, strongly downregulates the levels
CLN3
,
BCK2
, and
CDC28
mRNAs. Furthermore, mutations in
PFK1
and
PFK2
, which encode phosphofructokinase isoforms, inhibit glucose induction of
CLN3
,
BCK2
, and
CDC28
. These results indicate a link between the rate of glycolysis and the expression of genes that are critical for passage through G
1
.
Selection on the Genes of
Euplotes crassus
Tec1 and Tec2 Transposons: Evolutionary Appearance of a Programmed Frameshift in a Tec2 Gene Encoding a Tyrosine Family Site-Specific Recombinase
Authors: Doak Thomas G. , Witherspoon David J. , Jahn Carolyn L. , Herrick Glenn
Published: February 2003

The Tec1 and Tec2 transposons of the ciliate
Euplotes crassus
carry a gene for a tyrosine-type site-specific recombinase. The expression of the Tec2 gene apparently uses a programmed +1 frameshift. To test this hypothesis, we first examined whether this gene has evolved under purifying selection in Tec1 and Tec2. Each element carries three genes, and each has evolved under purifying selection for the function of its encoded protein, as evidenced by a dearth of nonsynonymous changes. This distortion of divergence is apparent in codons both 5′ and 3′ of the frameshift site. Thus, Tec2 transposons have diverged from each other while using a programmed +1 frameshift to produce recombinase, the function of which is under purifying selection. What might this function be? Tyrosine-type site-specific recombinases are extremely rare in eukaryotes, and Tec elements are the first known eukaryotic type II transposons to encode a site-specific recombinase. Tec elements also encode a widespread transposase. The Tec recombinase might function in transposition, resolve products of transposition (bacterial replicative transposons use recombinase or resolvase to separate joined replicons), or provide a function that benefits the ciliate host. Transposons in ciliated protozoa are removed from the macronucleus, and it has been proposed that the transposons provide this “excisase” activity.
Mapping underground London: the cultural politics of nature, technology and humanity
Authors: Rycroft Simon
Published: February 2003

An understanding of the geographies of resistance benefits from an exploration of alternative geographical imaginations. A focus on the London based counter-culture of the 1960s illustrates this point. The oppositional geographies of the counter-culture can be mapped using the London underground press as both source and object. In doing so, the underground’s peculiar constructions of the relationships between nature, technology and humanity can be traced. The (‘new’) leftist movements of the 1960s are not of primary interest here. Rather, the less conventional forms of cultural politicking from that period are the focus. Factions who were engaged in a range of activities, from the seemingly esoteric production of light-shows, through the ‘weekend hippy’ up from the home counties, to the editors of radical underground papers, attempted to operationalize a range of contemporaneous social, cultural and media theories in their project to redefine the discourse of dissent. In doing so, claims to primordial naturalness were made on the basis that new electronic technologies were extensions of the natural human self and could, if correctly utilized, reinsert nature into culture and consciousness. This same geographical imagination was used as a tool to avoid appropriation. By focusing upon the discursive aspects of resistance it is possible to draw a more nuanced account of the relationship between power and dissent that renders it less polarized and more symbiotic.
The Kármán gait: novel body kinematics of rainbow trout swimming in a vortex street
Authors: Liao James C. , Beal David N. , Lauder George V. , Triantafyllou Michael S.
Published: February 2003

Most fishes commonly experience unsteady flows and hydrodynamic perturbations during their lifetime. In this study, we provide evidence that rainbow trout Oncorhynchus mykiss voluntarily alter their body kinematics when interacting with vortices present in the environment that are not self-generated. To demonstrate this, we measured axial swimming kinematics in response to changes in known hydrodynamic wake characteristics. We compared trout swimming in the Kármán street behind different diameter cylinders (2.5 and 5 cm) at two flow speeds (2.5 and 4.5 Ls-1, where L is total body length) to trout swimming in the free stream and in the cylinder bow wake. Trout swimming behind cylinders adopt a distinctive, previously undescribed pattern of movement in order to hold station, which we term the Kármán gait. During this gait,body amplitudes and curvatures are much larger than those of trout swimming at an equivalent flow velocity in the absence of a cylinder. Tail-beat frequency is not only lower than might be expected for a trout swimming in the reduced flow behind a cylinder, but also matches the vortex shedding frequency of the cylinder. Therefore, in addition to choosing to be in the slower flow velocity offered behind a cylinder (drafting), trout are also altering their body kinematics to synchronize with the shed vortices (tuning), using a mechanism that may not involve propulsive locomotion. This behavior is most distinctive when cylinder diameter is large relative to fish length. While tuning, trout have a longer body wavelength than the prescribed wake wavelength, indicating that only certain regions of the body may need to be oriented in a consistent manner to the oncoming vortices. Our results suggest that fish can capture energy from vortices generated by the environment to maintain station in downstream flow. Interestingly, trout swimming in front of a cylinder display lower tail-beat amplitudes and body wave speeds than trout subjected to any of the other treatments, implying that the bow wake may be the most energetically favorable region for a fish to hold station near a cylinder.
Rapid fabrication and replication of metal, ceramic and plastic mould inserts for application in microsystem technologies
Authors: Pfleging W , Hanemann T , Torge M , Bernauer W
Published: February 2003

The process strategy for the rapid fabrication of microcomponents made of polymers will be presented. Different fabrication routes have been developed at Forschungszentrum Karlsruhe GmbH within the microsystem technology programme focusig on replication techniques. Single prototypes can be generated by the direct patterning of plastics with excimer laser radiation. For the fabrication of very small series laser-assisted micromachining, neodymium-doped yttrium aluminium garnet (Nd:YAG) and krypton fluorine (KrF) excimer laser radiation allows for the rapid manufacturing of microstructured mould inserts made of plastics, steel, cemented carbide or ceramics. The applied mould insert material depends on the achievable low surface roughness values essential for the subsequent moulding process. Plastic replication such as hot embossing, injection moulding or reaction injection moulding of the generated microstructured mould inserts gives access to mouldings carrying structural details in the micrometre range and/or high aspect ratio microstructures.
The verdict on jury trials for juveniles: the effects of defendant's age on trial outcomes
Authors: Warling Diane , Peterson‐Badali Michele
Published: February 2003

With the progression to more adult‐like policies and procedures for youth in the justice system, the right to a jury trial has been extended to young offenders. These youth would not be tried by a jury of their peers, however, but by a jury of adults. The concern is that adult jurors may hold negative attitudes about youth that might influence their decision making in a case involving a young defendant. Two studies examined whether and under what conditions defendant's age affects jurors' decisions about the guilt and sentencing of an accused. In study 1, data were gathered from two samples of jury eligible adults: one university sample and one public sample. Mock jurors read written transcripts of a trial involving a defendant who was presented as either 13, 17, or 25 years of age. Results indicated that the defendant's age had no effect on mock jurors' verdict or their ratings of defendant guilt. However, younger defendants were granted shorter sentences than the adult defendants. In study 2, mock jurors read the same trial presented in study 1 but were asked to deliberate about the case and render group verdicts. These group verdicts did not differ significantly by defendant's age. Age‐related themes that emerged from group deliberations were identified, and results indicated that age tended to be used as a mitigating factor in favor of youth rather than against them. These findings are discussed in terms of their implications for youth justice policy and practice. Copyright © 2003 John Wiley & Sons, Ltd.
Reduction of flobufen in pig hepatocytes: Effect of pig breed (domestic, wild) and castration
Authors: Skálová Lenka , Wsól Vladimír , Baliharová Vendula , Král Radim , Szotáková Barbora , Velík Jakub , Lamka Jirí
Published: February 2003

Knowledge of the biotransformation processes of veterinary drugs and food supplements in food‐producing animals is increasingly important. Residual levels of parent compounds or their metabolites in food of animal origin may differ with the breed, breeding conditions, and gender of animals. The nonsteroidal antiinflammatory drug flobufen, 4‐(2′,4′‐difluorobiphenyl‐4‐yl)‐2‐methyl‐4‐oxobutanoic acid (racemic or its individual enantiomers) was used as a model to evaluate differences in activity, stereoselectivity, and stereospecificity of reductases in primary cultures of hepatocytes from intact male or castrated male domestic pigs (Sus scrofa domestica) or male wild pig (Sus scrofa scrofa). Time‐dependent consumption of flobufen enantiomers and formation of dihydroflobufen (DHF) diastereoisomers as their principal metabolites in hepatocytes were measured using chiral HPLC. Flobufen reduction in hepatocytes from all three experimental groups of animals was stereoselective ((+)‐R‐flobufen was predominantly metabolized) and stereospecific (2R;4S‐DHF and 2S;4S‐DHF diastereoisomers were preferentially formed). Flobufen reductases activity in male domestic pigs was 30 times higher compared to castrated pigs. Flobufen reductases activity was similar in domestic and wild pigs. The stereospecificity and stereoselectivity of DHF production did not significantly differ with breed or castration of animal. Chiral inversion of flobufen enantiomers was also studied and differences between castrated and intact male pigs were seen. Chirality 15:213–219, 2003. © 2003 Wiley‐Liss, Inc.
Incontinent ileovesicostomy in the management of neurogenic bladder dysfunction
Authors: Gauthier Anthony R. , Winters J. Christian
Published: February 2003

Aims

To report outcome and urodynamic follow‐up of incontinent ileovesicostomy in quadriplegic patients with neurogenic bladder.

Methods

Seven patients (five male, two female; mean age, 33.7 yr) with neurogenic bladder underwent ileovesicostomy for management of leakage or complications of chronic catheter drainage. Five had chronic indwelling catheters: three suprapubic and two urethral. Preoperatively, all had upper tract evaluation and videourodynamics. All seven patients had detrusor hyperreflexia. Preoperative detrusor leak point pressures averaged 42.7 cm H2O. Two females had intrinsic sphincteric deficiency from prolonged Foley catheter drainage. Ileovesicostomy involves isolation of a 15—20‐cm segment of terminal ileum. The proximal 6–8 cm of this segment is opened on the antimesenteric border. The dome of the bladder is opened widely in a transverse manner and the proximal portion of the bowel is sutured onto the bladder. The distal portion of the ileum remains tubularized and becomes the stoma.

Results

There were no intraoperative complications. Operative time averaged 159 minutes. Associated procedures included removal of bladder calculus (n = 1), pubovaginal sling (n = 2), and Marshall Marchetti Krantz suspension (n = 1). Mean blood loss was <200 cc in six patients. Mean hospital stay was 8 days. Complications in two patients included: fascial stenosis requiring stoma revision (n = 1), wound infection (n = 1), and postoperative ileus (n = 1). Mean follow‐up was 37.4 months. Postoperatively, mean detrusor leak point pressures were 16.7 cm H2O (P = 0.0061). Patient satisfaction is high with only one complaint of occasional difficulty fitting the appliance.

Conclusions

Ileovesicostomy is an effective method of urinary drainage in quadriplegic patients. Detrusor leak point pressures were lowered, and upper tracts were preserved. No long‐term complications were encountered. Neurourol. Urodynam. 22:142–146, 2003. © 2003 Wiley‐Liss, Inc.
Minimizing SONET ADMs in unidirectional WDM rings with grooming ratio 3
Authors: Bermond Jean‐Claude , Ceroi Stephan
Published: February 2003

We consider traffic grooming in WDM unidirectional rings with all‐to‐all uniform unitary traffic. We determine the minimum number of SONET/SDH add–drop multiplexers (ADMs) required when the grooming ratio is 3. In fact, using tools of design theory, we solve the equivalent edge‐partitioning problem: Find a partition of the edges of the complete graph on n vertices (Kn) into subgraphs having at most three edges and in which the total number of vertices has to be minimized. © 2003 Wiley Periodicals, Inc.
Semiempirical local spin: Theory and implementation of the ZILSH method for predicting Heisenberg exchange constants of polynuclear transition metal complexes
Authors: O'Brien Ted A. , Davidson Ernest R.
Published: February 2003

The local spin formalism (Clark, A. E.; Davidson, E. R. J Chem Phys 2001, 115, 7382–7392) for computing expectation values 〈SA· SB〉 that appear in the Heisenberg spin model has been extended to semiempirical single determinant wave functions. An alternative derivation of expectation values in restricted and unrestricted cases is given that takes advantage of the zero differential overlap (ZDO) approximation. A formal connection between single determinant wave functions (which are not in general spin eigenfunctions) and the Heisenberg spin model was established by demonstrating that energies of single determinants that are eigenfunctions of the local spin operators with eigenvalues corresponding to high‐spin radical centers are given by the same Heisenberg coupling constants {JAB} that describe the true spin states of the system. Unrestricted single determinant wave functions for transition metal complexes are good approximations of local spin eigenfunctions when the metaldorbitals are local in character and all unpaired electrons on each metal have the same spin (although spins on different metals might be reversed). Good approximations of the coupling constants can then be extracted from local spin expectation values 〈SA· SB〉 energies of the single determinant wave functions. Once the coupling constants are obtained, diagonalization of the Heisenberg spin Hamiltonian provides predictions of the energies and compositions of the spin states. A computational method is presented for obtaining coupling constants and spin‐state energies in this way for polynuclear transition metal complexes using the intermediate neglect of differential overlap Hamiltonian parameterized for optical spectroscopy (INDO/S) in the ZINDO program. This method is referred to as ZILSH, derived from ZINDO, Davidson's local spin formalism, and the Heisenberg spin model. Coupling constants and spin ground states obtained for 10 iron complexes containing from 2 to 6 metals are found to agree well with experimental results in most cases. In the case of the complex [Fe6O3(OAc)9(OEt)2(bpy)2]+,a prioripredictions of the coupling constants yield a ground‐state spin of zero, in agreement with variable‐temperature magnetization data, and corroborate spin alignments proposed earlier on the basis of structural considerations. This demonstrates the potential of the ZILSH method to aid in understanding magnetic interactions in polynuclear transition metal complexes. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
The Effect of Acidosis on the Ecg of the Rat Heart
Authors: Aberra A. , Komukai K. , Howarth F. C. , Orchard C. H.
Published: February 2003

We have investigated the effect of acidosis on the ECG in isolated rat heart to determine whether acidosis has marked effects on the ECG, and have used pharmacological agents to investigate possible mechanisms whereby acidosis alters the ECG. Acidosis produced a marked decrease in heart rate and an increase in P‐R interval with little apparent effect on the duration of the QRS complex. The effects of acidosis did not appear to be due to acidosis‐induced changes in transmitter release from severed autonomic nerve terminals within the heart.
Somatotopy of Perceptual Threshold to Cutaneous Electrical Stimulation in Man
Authors: Davey Nick J. , Nowicky Alex V. , Zaman Rashid
Published: February 2003

Neurological testing tools for measuring and monitoring somatosensory function lack resolution and are often dependent on the clinician testing. In this study we have measured perceptual threshold (PT) to electrical stimulation of the skin and compared it with two‐point discriminative ability (TPDA) in 12 control subjects. Tests were made on both sides of the body at American Spinal Injury Association (ASIA) key points on seven spinal dermatomes (C3 (neck), C4 (shoulder), C5 (upper arm), C6 (thumb), T8 (abdomen), L3 (knee), L5 (foot)) and in the mandibular (chin) and maxillary (cheek) fields of the trigeminal (V) nerve. Electrical stimulation (0.5 ms pulse width; 3 Hz) was applied via a self‐adhesive cathode and an anode strapped to the wrist or ankle. The stimulus intensity was adjusted and PT was recorded as the lowest current at which the subject reported sensation. Sites were tested in random order. Indices for both TPDA and PT differed according to the dermatome tested but there was no correlation between TPDA and PT for any dermatome. There was good correlation between results from equivalent dermatomes on left and right sides for both PT and TPDA. Women frequently had lower mean (± s.e.) PTs and better TPDA than men; differences were significant (P < 0.05) for PT on the knee (women, 1.31 ± 0.15 mA; men, 2.05 ± 0.26 mA) and the foot (women, 2.90 ± 0.19 mA; men, 4.13 ± 0.28 mA) and for TPDA on the thumb (women, 3.8 ± 0.2 mm; men, 7.8 ± 1.3 mm) and the knee (women, 17.8 ± 1.6 mm; men, 27.1 ± 4.0 mm). Four subjects repeated the experiment on another day and the results correlated well with the first test for PT (r2, 0.62) and TPDA (r2, 0.48). PT differs between dermatomes in a predictable way but does not relate to TPDA. PT is easy to measure and may be a useful assessment tool with which to monitor recovery or deterioration in neuropathies, neurotrauma or after surgery.
Re‐Expression of Pulmonary Surfactant Proteins Following Tracheal Obstruction in Fetal Sheep
Authors: Lines A. , Gillett A. M. , Phillips I. D. , Wallace M. J. , Hooper S. B.
Published: February 2003

Increased fetal lung expansion, induced by tracheal obstruction (TO), is a potent stimulus for fetal lung growth, but rapidly reduces surfactant protein (SP) mRNA levels. Our aim was to determine the time course for the re‐expression of the surfactant proteins in fetal lung tissue following the release of a TO and to relate these to the changes in lung liquid volume. Fetal sheep were exposed to either: (1) no treatment (controls); (2) 4 days of TO; (3) 4 days of TO, followed by release of the obstruction for 24 h; (4) 4 days of TO followed by release of the obstruction for 3 days. Four days of TO increased lung liquid volumes from 26.8 ± 1.9 to 72.0 ± 5.6 ml kg−1 and reduced SP‐A, SP‐B and SP‐C mRNA levels to 38.5 ± 10.7, 56.8 ± 10.3 and 18.3 ± 5.3% of control values, respectively. One day after TO release, lung liquid volumes were reduced to 17.4 ± 5.3 ml kg−1 (control 128 days, 31.0 ± 3.8 ml kg−1) and SP‐A and SP‐B mRNA levels were not different from control levels. In contrast, SP‐C mRNA levels only increased to 45.4 ± 17.3% of control. Three days after TO release, lung liquid volumes increased to 48.0 ± 8.5 ml kg−1 and SP‐A and SP‐B mRNA levels were reduced to 48.8 ± 10.2% and 71.5 ± 19.8% of control, respectively; SP‐C mRNA levels remained at 35.3 ± 12.3% of control. Following the release of a TO, SP‐A, SP‐B and SP‐C mRNA levels were closely and inversely related to the volume of lung liquid. Based on these relationships, the lung liquid volumes that equate to 100% expression were considerably less than control lung volumes (< 10 vs. 30‐40 ml kg−1) in fetuses of this age. Thus, the changes in fetal lung SP‐A, SP‐B and SP‐C mRNA levels following the release of a TO are variable, differ between the proteins and are closely related to the changes in lung liquid volumes. We conclude that the re‐expression of surfactant proteins following TO is variable and that the change in lung liquid volume is potentially a good indicator for surfactant protein re‐expression.