bluuebunny/crossref_metadata_2025 huggingface dataset:
Vectorcardiography Risk Stratifies Emergency Department Chest Pain Patients with Left Ventricular Hypertrophy on the Initial 12‐Lead ECG
Authors: Fesmire Francis M. , Eriksson Sven V.
Published: April 2004

Background: Vectorcardiographic (VCG) measurements of ST‐vector magnitude (VM) and QRS‐vector difference (VD) have been demonstrated to be independent predictors of adverse outcome (AO) and acute myocardial infarction (AMI) in emergency department (ED) chest pain patients with absence of bundle branch block or left ventricular hypertrophy (LVH) on the initial 12‐lead electrocardiogram (ECG). The prognostic value of ST‐VM and QRS‐VD in ED chest pain patients with LVH on the initial 12‐lead ECG has not been previously investigated.

Methods: A prospective observational study was performed in 196 consecutive ED chest pain patients with suspected AMI and presence of voltage criteria for LVH on initial ECG who underwent continuous VCG monitoring during the initial evaluation. The optimal baseline ST‐VM value and 2‐hour QRS‐VD value were defined as the most accurate value on the receiver operator characteristic curve (value with lowest false‐negative and false‐positive rate). Thirty‐day AO was defined as AMI, percutaneous coronary intervention, coronary artery bypass grafting (CABG), or cardiac death occurring within 30 days of initial ED visit.

Results: Fourteen patients (7.1%) were diagnosed as 24‐hour AMI and 28 patients (14.3%) experienced 30‐day AO. The optimal cut‐off value for predicting 30‐day AO was >124 μV for ST‐VM and >21.7 μV for QRS‐VD. Patients with either a positive ST‐VM or a positive QRS‐VD had 8.8 times increased odds of AMI (95% confidence interval, CI, 1.9–40.3; P = 0.003); 4.3 times increased odds of 30‐day PTCA/CABG (95% CI 1.3–13.8; P = 0.019); and 3.8 times increased odds of 30‐day AO (95% CI 1.6–9.3; P = 0.003).

Conclusions: Baseline ST‐VM and 2‐hour QRS‐VD risk stratifies ED chest pain patients with LVH voltage criteria on the initial 12‐lead ECG.
Susceptibility of GTR‐regenerated periodontal attachment to ligature‐induced periodontitis
Authors: Kostopoulos Lambros , Karring Thorkild
Published: April 2004

Aim: This study aimed to compare the susceptibility of guided tissue regeneration (GTR)‐regenerated periodontal attachment to ligature‐induced periodontitis with that of the pristine periodontium.

Methods: Periodontal breakdown was produced in four monkeys by the placement of orthodontic elastics around experimental teeth (test teeth). During a flap operation, the root surfaces were scaled and planed, and a notch indicating the apical termination of scaling and root planing was made in the root surface. Following resection of the crowns and endodontic treatment, an e‐PTFE membrane was adapted over the roots. Subsequently, the flaps were sutured to complete closure of the wound (submerged). At membrane removal after 5 weeks, the crowns of the contralateral teeth serving as controls were resected, and the roots treated endodontically during a flap operation. Artificial composite crowns were then placed on both test and control roots. After 3 months of tooth cleaning, cotton floss ligatures were placed passively around both test and control teeth for a period of 6 months. Two weeks later the animals were sacrificed.

Results: Histological analysis demonstrated that the instrumented root surfaces of the test teeth were covered by newly formed cementum of the reparative, cellular, extrinsic and intrinsic fiber type, while the cementum on the controls was mainly acellular extrinsic fiber cementum. Histometric assessments demonstrated that similar attachment loss had occurred on test (1.0±0.5 mm) and control roots (1.0±0.4 mm) during the 6 months of ligature‐induced plaque accumulation.

Conclusion: The results indicate that teeth with a periodontal attachment apparatus formed by GTR is not more susceptible to periodontitis than those with a pristine periodontium.
Effects of simulated obstructive sleep apnoea on the human carotid baroreceptor–vascular resistance reflex
Authors: Cooper V. L. , Bowker C. M. , Pearson S. B. , Elliott M. W. , Hainsworth R.
Published: April 2004

Obstructive sleep apnoea (OSA), which is characterized by periodic inspiratory obstruction, is associated with hypertension and possibly with changes in the baroreceptor reflex. In this investigation we induced changes in inspiratory resistance and in inspiratory oxygen and carbon dioxide content, which simulate some of the changes in OSA, to determine whether this caused changes in the gain or setting of the carotid baroreflex. In eight healthy subjects (aged 21–62 years) we changed the stimulus to carotid baroreceptors, using neck chambers and graded pressures of −40 to +60 mmHg, and assessed vascular resistance responses in the brachial artery from changes in blood pressure (Finapres) divided by brachial artery blood flow velocity (Doppler ultrasound). Stimulus–response curves were defined during (a) sham (no additional stimulus), (b) addition of an inspiratory resistance (inspiratory pressure −10 mmHg), (c) breathing asphyxic gas (12% O2, 5% CO2), and (d) combined resistance and asphyxia. Sigmoid or polynomial functions were applied to the curves and maximum differentials (equivalent to peak gain) and the corresponding carotid pressures (equivalent to ‘set point’) were determined. The sham test had no effect on either gain or ‘set point’. Inspiratory resistance alone had no effect on blood pressure and did not displace the curve. However, it reduced gain from −3.0 ± 0.6 to −2.1 ± 0.4 units (P < 0.05). Asphyxia alone did increase blood pressure (+7.0 ± 1.1 mmHg, P < 0.0005) and displaced the curve to higher pressures by +16.8 ± 2.1 mmHg (P < 0.0005). However, it did not affect gain. The combination of resistance and asphyxia both reduced gain and displaced the curve to higher pressures. These results suggest that inspiratory resistance and asphyxia cause changes in the baroreceptor reflex which could lead to an increase in blood pressure. These changes, if sustained, could provide a mechanism linking hypertension to obstructive sleep apnoea.
Filtration rate dependence of hyaluronan reflection by joint‐to‐lymph barrier: evidence for concentration polarisation
Authors: Sabaratnam S. , Mason R. M. , Levick J. R.
Published: April 2004

Hyaluronan (HA), a component of synovial fluid, buffers fluid loss from joints. To explain this, a quantitative theory for HA concentration polarisation at a partially sieving synovial lining was developed. The theory predicts a fall in HA reflected fraction R with increased filtration rate. To test this, knees of anaesthetised rabbits were infused with HA and fluorescein–dextran (FD) at constant trans‐synovial filtration rates of 6–89 μl min−1. Samples of femoral lymph, mixed intra‐articular fluid and subsynovial fluid after ≥ 3 h were analysed by high‐performance liquid chromatography. R was calculated as (1 – downstream/upstream concentration), using [FD] to adjust for joint lymph dilution in femoral lymph. Intra‐articular HA concentration after ≥ 3 h, 0.47 ± 0.02 mg ml−1 (mean ±s.e.m., n= 31), exceeded the infusate concentration, 0.20 mg ml−1, while subsynovial and lymph [HA] were reduced relative to [FD]. The changes in [HA] demonstrated synovial molecular sieving of HA. R from cavity to lymph (Rlymph) fell monotonically from 0.93 at 6 μl min−1 to 0.14 at 89 μl min−1 (P < 0.0001, regression analysis, n= 33). R values calculated from the intra‐articular HA accumulation (Rasp) or the low subsynovial concentrations (Rsyn) were similar negative functions of filtration rate. R for lymphatic capillary endothelium (Rendo), calculated from lymph/subsynovial concentration ratios, was effectively zero (−0.03 ± 0.18, n= 21), confirming that synovium, not initial lymphatic endothelium, is the reflection site. Logarithmic linearisation of the results evaluated the synovial HA reflection coefficient as 0.91. In conclusion, the existence of concentration polarisation during joint fluid drainage was supported by the demonstration of a negative relation between filtration rate and Rlymph, Rasp and Rsyn.
Early receptor current of wild‐type and transducin knockout mice: photosensitivity and light‐induced Ca2+ release
Authors: Woodruff Michael L. , Lem Janis , Fain Gordon L.
Published: April 2004

We have used suction‐electrode recording to measure the early receptor current (ERC) from single, isolated mammalian photoreceptors. When a wild‐type mouse rod was illuminated with light sufficient to close all the cGMP‐gated channels, a succeeding bright laser flash bleaching a large proportion of the visual pigment produced an ERC, which at 37°C consisted primarily of a single component of transient positive current. The amplitude of total charge movement of this component declined exponentially with successive flashes, consistent with the direct proportionality of the ERC to the quantity of pigment bleached. From the constant of exponential decline, it was possible to estimate the in vivo photosensitivity of mouse rhodopsin to be about 6 × 10−9μm2 per molecule. We have also measured the ERC from rods of transducin‐knockout mice, for which previous illumination to close the cGMP‐gated channels was not required. The ERC of these rods was similar to that of wild‐type rods but was followed by a slow component of outward current whose maximum amplitude in some cells approached that of the normal light response. This slow current was blocked by l‐cis diltiazem, indicating that it was produced by ion flux through the cyclic nucleotide‐gated channels of the outer segment; however, it could not have been produced by the normal transduction cascade, since it was recorded from rods lacking transducin. Since it was depressed by prior incorporation of the Ca2+ buffer BAPTA, it was probably generated by light‐activated Ca2+ release earlier demonstrated in salamander and zebrafish. Recordings of the ERC from normal and mutant mice may provide a useful tool for the analysis of models of retinal disease, as well as exploration of the molecular origin of light‐activated Ca2+ release.
Noncommutative quantum mechanics
Authors: Girotti H. O.
Published: April 2004

We discuss the main features of noncommutative quantum mechanics, a version of nonrelativistic quantum mechanics that involves noncommuting coordinates. After finding a representation for the algebra obeyed by the coordinates and momenta, we analyze the changes due to the noncommutative nature of the coordinates. The noncommutative two-dimensional harmonic oscillator is discussed in detail. Under certain restrictions, the effect of the noncommutativity is found to be equivalent to a Landau interaction. The modifications produced by the noncommutativity on the thermodynamic functions of the oscillator also are studied.
A density functional perspective for single-particle systems
Authors: Neal H. L.
Published: April 2004

Density functional theory is discussed in the context of single-particle systems in one spatial dimension. We show that the ground state density ρ0(x) and energy E0 are simply related to a family of external potential energy functions with ground state wave functions ψn(x)∝ρ0(x)n and energies En=2nE0 for certain integer values of n.
Understanding the CPT group in particle physics: Standard and nonstandard representations
Authors: Scurek Raymond
Published: April 2004

We explore the CPT group in a manner that is not typically found in quantum mechanics textbooks, revealing a larger structure than is commonly known. After a brief review of the restricted Poincaré group, we derive the irreducible representations of single-particle quantum mechanical states of the discrete elements of the extended Poincaré group adjoined by charge conjugation. We show that there are 16 different irreducible representations of the discrete operations of charge conjugation C, space inversion P, and time reversal T. The familiar conventional representations are identified and interpretations of the unconventional irreducible representations that lead to a doubling of the space of states under time reversal are discussed.
A microscopic, mechanical derivation of the adiabatic gas relation
Authors: Bellan P. M.
Published: April 2004

It is shown that the ideal gas adiabatic relation, PVγ=constant, can be derived by considering the motion of a particle bouncing elastically between a stationary wall and a moving wall.
The chemical potential of an ideal intrinsic semiconductor
Authors: Shegelski Mark R. A.
Published: April 2004

The standard result for the chemical potential μ of an ideal intrinsic semiconductor as calculated in the canonical ensemble indicates that μ goes to the middle of the band gap as the temperature T goes to zero. However, the definition of μ implies that μ goes to the bottom of the conduction band as T→0. The solution to this puzzle is that the Fermi–Dirac distribution function ceases to be accurate for the thermal occupation probabilities when the temperature is so low that the number of electrons in the conduction band is of order unity. The use of the correct occupation numbers results in μ going to the bottom of the conduction band as T→0.
A beam chopping experiment to help students develop research skills
Authors: Behringer Ernest R. , Brincat Joseph A.
Published: April 2004

We describe a project involving the beam chopping process that develops student skills in modeling, computation, experimentation, and data acquisition and can be completed by introductory physics students.
Model of the 2003 Tour de France
Authors: Hannas Benjamin Lee , Goff John Eric
Published: April 2004

We modeled the 2003 Tour de France bicycle race using stage profile data for which elevations at various points in each stage are known. Each stage is modeled as a series of inclined planes. We accounted for the forces on a bicycle-rider combination such as aerodynamic drag and rolling resistance and calculated the winning stage times for an assumed set of bicycle and rider parameters. The calculated total race time differed from the sum of all actual winning stage times by only 0.03%.
Capacitors can radiate: Further results for the two-capacitor problem
Authors: Choy T. C.
Published: April 2004

Using a point dipole radiator approximation, we extend the study of Boykin, Hite, and Singh [Am. J. Phys. 70 (4), 415–420 (2002)] by considering electromagnetic radiation from both the capacitors and the wire loop to account for the missing energy in the popular two-capacitor Kirchoff circuit. Through a series of gedanken experiments in which successively more realistic circuit elements are added, we assess the significance of electromagnetic radiation in accounting for all the missing energy. Extensive use is made of an energy partition function to obtain many results without an explicit solution of nonlinear differential equations. However some difficulties remain, which are posed by the required boundary conditions when an inductance L is included. Implications for radio frequency interference, as well as novel antenna designs are also discussed.
Lorentz invariance of neutrino oscillations
Authors: Giunti C.
Published: April 2004

It is shown that, in spite of appearances, the standard expression for the oscillation probability of ultrarelativistic neutrinos is Lorentz invariant.
Enhancing conceptual change using argumentative essays
Authors: Kalman Calvin S. , Rohar Shelley , Wells David
Published: April 2004

We show the utility of following up collaborative group work with written exercises. In a previous paper we discussed promoting conceptual change using collaborative group exercises in a manner based on the notion of conceptual conflict developed by Hewson and Hewson in which representatives of differing viewpoints debate their outlook. In this paper, we describe an enhancement of this method based on Feyerabend’s principle of counterinduction—the process by which one theory or idea is used to affect change in its rival. Students were required to follow up the conceptual conflict exercises with a written critique. Evaluations were done using the same enhanced version of the force concept inventory as administered to the students in the previous study.
A nanodevice for rectification and pumping ions
Authors: Siwy Zuzanna , Fuliński Andrzej
Published: April 2004

The transport properties of single asymmetric nanopores in polyetheylene terephthalate (PET) are examined. The pores were produced by a track etching technique based on the irradiation of the foils by swift heavy ions and subsequent chemical etching. Electrical conductivity measurements show that the nanopores in PET are cation selective and rectify the current with the preferential direction of cation flow from the narrow entrance toward the wide opening of the pore. Moreover, the pore transports potassium ions against the concentration gradient if stimulated by external field fluctuations. We show that the rectifying and pumping effects are based on the ratchet mechanism.
Simple games to illustrate Parrondo’s paradox
Authors: Martin Hal , von Baeyer Hans Christian
Published: April 2004

Parrondo’s paradox is the proposition that two losing strategies can, by alternating randomly, produce a winner. R. D. Astumian has recently created a simple board game to illustrate this counterintuitive phenomenon. We prove that the inherent symmetry of Astumian’s game prevents it from achieving its purpose, and suggest amended versions that do. We also display the additional paradoxical effect of two slow, losing games combining into a fast, winning one.
“If you think you’ve got a lump, they’ll screen you.” Informed consent, health promotion, and breast cancer: Table 1
Authors: Pfeffer N
Published: April 2004

A great deal has been written about information that is or should be provided when seeking consent to medical research and treatment. Relatively little attention has been paid to information describing health promotion interventions. This paper critically examines some information material describing three different methods of encouraging early presentation of breast cancer in the UK: the NHS breast screening programme, breast self examination, and breast awareness. Findings from a content analysis of printed material and a series of focus group discussions that included women who speak little or no English were organised around the Department of Health’s recommendations about the information which should be provided when seeking consent to treatment and research. They exposed inconsistencies, ambiguities, and gaps, which when taken together suggest both compliance and non-compliance are being achieved in the absence of informed consent. The findings also provide a starting point for a discussion about how informed consent to health promotion might be sought.
Ethics and evidence based surgery
Authors: Stirrat G M
Published: April 2004

Traditionally, surgical practice has been experiential and based on the contemporary understanding of basic mechanisms of disease. It was both a science and an art and depended to far too great an extent on the individualism and self belief of its main exponents. “Evidence based medicine” (EBM) emerged in the 1980s and a new gospel of “Rules of Evidence” was introduced. There is no doubt that the net effect of EBM has been beneficial, but over reliance on randomised controlled trials and the lack of generalisability of scientific evidence to individual patients has perhaps led to less enthusiasm for its tenets among surgeons. There are valid and spurious reasons for this that are discussed. The situation is improving but inevitable tensions remain between the surgeon committed to the individual patient here and now, and the clinical researcher whose focus is the benefit of future patients in the larger community.
Research ethics and evidence based medicine: Table 1
Authors: Lie R K
Published: April 2004

In this paper, the author argues that the requirement to conduct randomised clinical trials to inform policy in cases where one wants to identify a cheaper alternative to known effective but expensive interventions raises an important ethical issue. This situation will eventually arise whenever there are resource constraints, and a policy decision has been made not to fund an intervention on cost effectiveness grounds. It has been thought that this is an issue only in extremely resource poor settings. This paper gives an example from the United Kingdom illustrating that this is also a problem faced by richer countries.
Midodrine treatment for chronic fatigue syndrome
Authors: Naschitz J , Dreyfuss D , Yeshurun D , Rosner I
Published: April 2004

The long term results of midodrine treatment in a patient having debilitating chronic fatigue syndrome (CFS) are reported. Midodrine treatment, directed at the autonomic nervous system, resulted in correction of the dysautonomia followed by improvement of fatigue. This finding is consistent with the hypothesis that dysautonomia plays a major part in the pathophysiology of CFS and that therapies directed at the autonomic nervous system may be effective in the treatment of CFS.
Analgesia for patients with advanced disease: 2
Authors: Hall E J , Sykes N P
Published: April 2004

The first article in this series explored epidemiology and patterns of pain in advanced disease, non-pharmacological treatments, and the use of opioids to manage pain. This second article examines the use of non-opioid drugs and anaesthetic interventions for pain relief in advanced disease. It also discusses an approach to managing analgesia in dying patients and finally looks at future developments.
ATP downregulates P2X7 and inhibits osteoclast formation in RAW cells
Authors: Hiken Jeffrey F. , Steinberg Thomas H.
Published: April 2004

Multinucleated giant cells derive from fusion of precursor cells of the macrophage lineage. It has been proposed that the purinoreceptor P2X7 is involved in this fusion process. Prolonged exposure of macrophages to ATP, the ligand for P2X7, induces the formation of plasma membrane pores and eventual cell death. We took advantage of this cytolytic property to select RAW 264.7 (RAW) cells that lacked P2X7 function by maintaining them in ATP (RAW ATP-R cells). RAW ATP-R cells failed to fuse to form multinucleated osteoclasts in response to receptor activator nuclear factor-κB ligand, although they did become positive for the osteoclast marker enzyme tartrate-resistant acid phosphatase, and upregulated expression of other osteoclast marker genes. RAW ATP-R cells and wild-type RAW cells expressed similar amounts of P2X7 protein, but little P2X7 was present on the surface of RAW ATP-R cells. After ATP was removed from the medium of RAW ATP-R cells, the cells reexpressed P2X7 on the cell surface, regained sensitivity to ATP, and formed multinucleated osteoclasts. These results suggest that P2X7 or another protein that is downregulated in concert with P2X7 is involved either in the mechanics of cell fusion to form osteoclasts or in a signaling pathway proximal to this event. These results also suggest that P2X7 may be regulated by ligand-mediated internalization and that extracellular ATP may regulate the formation of osteoclasts and other multinucleated giant cells.
Hypotonic swelling stimulates L-type Ca2+ channel activity in vascular smooth muscle cells through PKC
Authors: Ding Yanfeng , Schwartz Dean , Posner Philip , Zhong Juming
Published: April 2004

It has been suggested that L-type Ca2+ channels play an important role in cell swelling-induced vasoconstriction. However, there is no direct evidence that Ca2+ channels in vascular smooth muscle are modulated by cell swelling. We tested the hypothesis that L-type Ca2+ channels in rabbit portal vein myocytes are modulated by hypotonic cell swelling via protein kinase activation. Ba2+ currents ( IBa) through L-type Ca2+ channels were recorded in smooth muscle cells freshly isolated from rabbit portal vein with the conventional whole cell patch-clamp technique. Superfusion of cells with hypotonic solution reversibly enhanced Ca2+ channel activity but did not alter the voltage-dependent characteristics of Ca2+ channels. Bath application of selective inhibitors of protein kinase C (PKC), Ro-31–8425 or Go-6983, prevented IBa enhancement by hypotonic swelling, whereas the specific protein kinase A (PKA) inhibitor KT-5720 had no effect. Bath application of phorbol 12,13-dibutyrate (PDBu) significantly increased IBa under isotonic conditions and prevented current stimulation by hypotonic swelling. However, PDBu did not have any effect on IBa when cells were first exposed to hypotonic solution. Furthermore, downregulation of endogenous PKC by overnight treatment of cells with PDBu prevented current enhancement by hypotonic swelling. These data suggest that hypotonic cell swelling can enhance Ca2+ channel activity in rabbit portal vein smooth muscle cells through activation of PKC.
Extracellular Na+ inhibits Na+/H+ exchange: cell shrinkage reduces the inhibition
Authors: Dunham Philip B. , Kelley Scott J. , Logue Paul J.
Published: April 2004

Na+/H+ exchangers (NHE) are ubiquitous transporters participating in regulation of cell volume and pH. Cell shrinkage, acidification, and growth factors activate NHE by increasing its sensitivity to intracellular H+ concentration. In this study, the kinetics were studied in dog red blood cells of Na+ influx through NHE as a function of external Na+ concentration ([Na+]o). In cells in isotonic media, [Na+]o inhibited Na+ influx >40 mM. Osmotic shrinkage activated NHE by reducing this inhibition. In cells in isotonic media + 120 mM sucrose, there was no inhibition, and influx was a hyperbolic function of [Na+]o. The kinetics of Na+-inhibited Na+ influx were analyzed at various extents of osmotic shrinkage. The curves for inhibited Na+ fluxes were sigmoid, indicating more than one Na+ inhibitory site associated with each transporter. Shrinkage significantly increased the Na+ concentration at half-maximal velocity of Na+-inhibited Na+ influx, the mechanism by which shrinkage activates NHE.
Cytokine gene expression in human skeletal muscle during concentric contraction: evidence that IL-8, like IL-6, is influenced by glycogen availability
Authors: Chan M. H. Stanley , Carey Andrew L. , Watt Matthew J. , Febbraio Mark A.
Published: April 2004

To determine the expression and induction of cytokines in human skeletal muscle during concentric contractions, eight males performed 60 min of bicycle exercise, with either a normal (Con) or reduced (Lo Gly) preexercise intramuscular glycogen content. Muscle biopsy samples were obtained before and after exercise and analyzed for glycogen and the mRNA expression of 13 cytokines. Resting muscle glycogen was higher ( P < 0.05) in Con compared with Lo Gly and was reduced ( P < 0.05) to 102 ± 32 vs. 17 ± 5 mmol U glycosyl/kg dry mass for Con and Lo Gly, respectively. We detected mRNA levels in human skeletal muscle for five cytokines, namely interleukin (IL)-1β, IL-6, IL-8, IL-15, and tumor necrosis factor-α. However, muscle contraction increased ( P < 0.05) the mRNA expression of IL-6 and IL-8 alone. In addition, the fold change for both IL-8 and IL-6 was markedly higher ( P < 0.05) in Lo Gly compared with Con. Given these results, we analyzed venous blood samples, obtained before and during exercise, for IL-6 and IL-8. Plasma IL-6 was not different at rest, and although the circulating concentration of this cytokine increased ( P < 0.05) it increased to a greater extent ( P < 0.05) throughout exercise in Lo Gly. In contrast, plasma IL-8 was not affected by exercise or treatment. These data demonstrate that cytokines are not ubiquitously expressed in skeletal muscle and that only IL-6 and IL-8 mRNA are increased during contraction of this mode and duration. Furthermore, the mRNA abundance of IL-6 and IL-8 appears to be influenced by glycogen availability in the contracting muscle.
Pathophysiology of functional mutations of the thiazide-sensitive Na-Cl cotransporter in Gitelman disease
Authors: Sabath Ernesto , Meade Patricia , Berkman Jennifer , de los Heros Paola , Moreno Erika , Bobadilla Norma A. , Vázquez Norma , Ellison David H. , Gamba Gerardo
Published: April 2004

Most of the missense mutations that have been described in the human SLC12A3 gene encoding the thiazide-sensitive Na+-Cl−cotransporter (TSC, NCC, or NCCT), as the cause of Gitelman disease, block TSC function by interfering with normal protein processing and glycosylation. However, some mutations exhibit considerable activity. To investigate the pathogenesis of Gitelman disease mediated by such mutations and to gain insights into structure-function relationships on the cotransporter, five functional disease mutations were introduced into mouse TSC cDNA, and their expression was determined in Xenopus laevis oocytes. Western blot analysis revealed immunoreactive bands in all mutant TSCs that were undistinguishable from wild-type TSC. The activity profile was: wild-type TSC (100%) > G627V (66%) > R935Q (36%) = V995M (32%) > G610S (12%) > A585V (6%). Ion transport kinetics in all mutant clones were similar to wild-type TSC, except in G627V, in which a small but significant increase in affinity for extracellular Cl−was observed. In addition, G627V and G610S exhibited a small increase in metolazone affinity. The surface expression of wild-type and mutant TSCs was performed by laser-scanning confocal microscopy. All mutants exhibited a significant reduction in surface expression compared with wild-type TSC, with a profile similar to that observed in functional expression analysis. Our data show that biochemical and functional properties of the mutant TSCs are similar to wild-type TSC but that the surface expression is reduced, suggesting that these mutations impair the insertion of a functional protein into the plasma membrane. The small increase in Cl−and thiazide affinity in G610S and G627V suggests that the beginning of the COOH-terminal domain could be implicated in defining kinetic properties.
Distribution of the tight junction proteins ZO-1, occludin, and claudin-4, -8, and -12 in bladder epithelium
Authors: Acharya Prasad , Beckel Jonathan , Ruiz Wily G. , Wang Edward , Rojas Raul , Birder Lori , Apodaca Gerard
Published: April 2004

In mammals, the bladder stores urine without permitting the passage of urine contents into the bloodstream, a function, in part, of the uroepithelial-associated tight junction complex. The protein constituents that make up this high-resistance barrier in the bladder are currently unknown, although the claudins, a multigene family, are thought to govern paracellular transport in other epithelia. Reverse transcriptase-polymerase chain reaction analysis was used to define that mRNA for claudin-2, -4, -8, -12, and -13 was expressed in mouse bladder tissue. The localization of these claudins, as well as the tight junction-associated proteins zonula occludens-1 (ZO-1) and occludin, within the bladder epithelium was determined by immunofluorescence microscopy. As expected, occludin and ZO-1 were localized to the tight junctions of rat, mouse, and rabbit umbrella cells. Intriguingly, ZO-1 in mouse epithelium, ZO-1 in the dome region of rabbit bladders and occludin in rat and mouse bladders were also expressed in the underlying intermediate and basal cell layers. Claudin-4, -8, and -12 were found in the umbrella cell tight junction; however, additional staining of claudin-4 was observed along the sites of cell-cell contact in the underlying cell layers of rat, mouse, and rabbit tissue. No claudin-2 staining was associated with tight junctions in the uroepithelium. Our results indicate that claudin-4, -8, and -12 are expressed in umbrella cells, where they may impart the high-resistance phenotype associated with this cell type, and that in some instances tight junction proteins are also associated at the sites of cell contact of the underlying cell layers, perhaps playing some role in cell-cell adhesion.
The Long Processes of Short Interfering RNAs – RNA Interference and Its Implications in Neuronal Cells
Authors: Lingor Paul , Michel Uwe , Bähr Mathias
Published: April 2004

Reverse genetics has been greatly advanced by the discovery of RNA interference (RNAi). This intracellular RNA-mediated gene silencing pathway is partially conserved from plants to mammals and offers a new powerful tool for the analysis of gene function. We give a brief overview of the discovery of RNAi, the underlying mechanisms and probable intrinsic roles of the pathway. Recent reports utilizing RNAi for gene silencing approaches in neuronal cells are reviewed and possible delivery techniques for small interfering RNA/double-stranded RNA are discussed.
Active Immunization of Mice with an Aβ-Hsp70 Vaccine
Authors: Koller Michael F. , Mohajeri M. Hasan , Huber Michael , Wollmer M. Axel , Roth Z’graggen Birgit V. , Sandmeier Erika , Moritz Eva , Tracy Jay , Nitsch Roger M. , Christen Philipp
Published: April 2004

Heat-shock proteins are highly immunogenic. Complexed with an antigen, they act as adjuvants, inducing a humoral and cellular immune response against both the antigen and the chaperone. In this study, we produced an Hsp70-supported vaccine to induce the generation of antibodies against amyloid-β (Aβ) peptides, the major constituent of β-amyloid plaques in Alzheimer’s disease. The vaccine consisted of synthetic human Aβ42 covalently cross-linked with DnaK, an Hsp70 homolog of Escherichia coli. Active immunization of mice with this vaccine resulted in the generation of antibodies against Aβ, that were detectable in sera after the first booster immunization. Antibody titers varied markedly with the genetic background of the mice. Prophylactic short-term immunization of transgenic mice (APP tg2576) before the onset of plaques, however, did not prevent amyloid plaque deposition. There were no differences in the plaque load and in the level of Triton X-100-soluble Aβ peptides in the brains of immunized and control-treated transgenic mice. Unexpectedly, the level of formic-acid soluble Aβ peptides tended to be higher in immunized mice. The reason for the increase may be an enhanced deposition of Aβ in the small cerebral blood vessels. These data emphasize the need for anti-Aβ antibodies that remove Aβ peptides from the central nervous system without negative side effects.
β-Amyloid Treatment Sensitizes Mice to Amphetamine-Induced Locomotion but Reduces Response to Caffeine
Authors: Dall’Igna Oscar P. , Hoffmann Anselmo , da Silva Adriana L. , Souza Diogo O. , Lara Diogo R.
Published: April 2004

Backgroud: Psychosis frequently occurs in Alzheimer’s disease (AD), being associated with more severe cognitive decline, but the underlying mechanisms are unknown. Objective: To investigate the effect of centrally administered β-amyloid peptide, a model for AD, in the locomotor response to amphetamine, caffeine and MK-801, which are psychoactive drugs related to neurochemical changes occurring in psychosis. Methods: Mice were intracerebroventricularly injected with β-amyloid (25–35), and after 1 week they were tested in the passive avoidance, spontaneous alternation and locomotor tasks. Results: Besides impaired performance in inhibitory avoidance and spontaneous alternation tasks, β-amyloid-treated mice showed increased spontaneous locomotion, augmented response to amphetamine (1.5 mg/kg), blunted response to caffeine (30 mg/kg) and no difference in MK-801 (0.25 mg/kg)-induced locomotor activation when compared to its respective control. Conclusion: These results are compatible with the hypothesis that β-amyloid peptide may predispose to psychotic symptoms of AD by increasing sensitivity of the dopaminergic system, possibly related to a decreased adenosinergic inhibitory tone.
Neonatal Capsaicin Treatment Affects Rat Thymocyte Proliferation and Cell Death by Modulating Substance P and Neurokinin-1 Receptor Expression
Authors: Santoni Giorgio , Amantini Consuelo , Lucciarini Roberta , Perfumi Marina , Pompei Pierluigi , Piccoli Mario
Published: April 2004

Herein we provide evidence that substance P (SP) and its neurokinin-1 receptor (NK-1R) expressed on thymocytes counteract thymus depletion induced by neonatal capsaicin (CPS) treatment by affecting thymocyte proliferation and apoptotic death. SP administration reversed the CPS-mediated inhibitory effects on the total thymocyte number and subset distribution, namely CD4+ and CD4– CD8– cells, through its interaction with NK-1R as shown by concomitant NK-1R (SR140333) antagonist administration. SP-induced enhancement of thymus cellularity parallels its ability of inhibiting the thymocyte apoptotic program. Indeed, exogenously administered SP completely nullified CPS-induced apoptosis, and SR140333 abrogated the SP-mediated protective effect. SP administration also stimulated concanavalin A (Con A)-induced thymocyte proliferation of CPS-treated rats, completely reversing the CPS-induced inhibition. The SP-mediated stimulation of Con A-induced thymocyte proliferation was NK-1R dependent as shown by concomitant administration of SP and SR140333 to CPS-treated rats. Our results also demonstrate that CPS treatment induces a marked decrease of thymocyte PPT-A mRNA level and endogenous SP content as evaluated by quantitative RT-PCR, in situ hybridization and cytofluorimetric analysis. By contrast, NK-1R mRNA levels were increased in thymocytes from CPS-treated rats. Exogenous SP administration augmented PPT-A, SP and NK-1R thymocyte expression in CPS-treated rats, and this enhancement was antagonized by SR140333 administration. Overall, our results strongly suggest that the immunomodulatory effects of neonatal CPS treatment on rat thymocyte functions are dependent on vanilloid-mediated regulation of SP and NK-1R functional expression by neuronal and immune cells.
Effects of Aminoguanidine and Cyclooxygenase Inhibitors on Nitric Oxide and Prostaglandin Production, and Nitric Oxide Synthase and Cyclooxygenase Expression Induced by Lipopolysaccharide in the Estrogenized Rat Uterus
Authors: Ribeiro María , Cella Maximiliano , Farina Mariana , Franchi Ana
Published: April 2004

Background/Objective: The aim of our study was first to investigate if there exists an interaction between nitric oxide (NO) and prostaglandin (PG) generation in the estrogenized rat uterus challenged by lipopolysaccharide (LPS), and, secondly, which isoforms of nitric oxide synthase (NOS) and cyclooxygenase (COX) participate in this process. Methods: To study the effect of LPS and to characterize the isoenzymes involved in the process, specific inhibitors of iNOS (aminoguanidine) and COX-II (meloxicam, nimesulide) and non-specific of COX (indomethacin) were injected intraperitoneally to determine their effect on NO and PG production, and on NOS and COX expression induced by LPS in estrogenized rat uterus. NO production was measured by arginine-citrulline conversion assay and PGE2/PGF2α, by radioconversion. Enzyme expression was evaluated by Western blot analysis. Results: The present work shows that iNOS inhibitor, aminoguanidine, reduced NO and PGE2/PGF2α production induced by LPS injection. Aminoguanidine exerts its effect over the PG metabolism by inhibiting COX-II activity and expression. On the other hand, both indomethacin, a non-selective PG inhibitor, and meloxicam, a COX-II inhibitor, stimulated NO production and reduced PGE2/PGF2α generation. Indomethacin also reduced COX-II and iNOS expression. Conclusion: These results indicate that in the estrogenized rat uterus challenged with LPS, PG and NO interact affecting each other’s metabolic pathways. The above findings indicate that the interaction between NOS and COX might be important in the regulation of physiopathologic events during pregnancy.
Neoadjuvante Chemotherapie bei Mammakarzinom
Authors: Rühl I. , Bauerfeind I. , Kahlert S. , Untch M. , Hepp H.
Published: April 2004

Während in der Vergangenheit die primär systemische Therapie (PST) eher für internistische Tumorentitäten eingesetzt wurde oder dem inoperablen Mammakarzinom vorbehalten war, ist zunehmend auch die Behandlung operabler Tumorstadien untersucht worden. Nachdem der Nachweis erfolgt war, dass PST der adjuvanten Therapie gegenüber äquieffektiv ist, wurden zahlreiche Studienkonzepte entwickelt. PST ermöglicht eine In-vivo-Chemosensitivitätstestung, so dass die Wirksamkeit der Behandlung am Ansprechen des Tumors beobachtet werden kann. Bei mangelndem Ansprechen kann auf ein nicht kreuzresistentes Konzept umgestellt werden, so dass in diesem Fall keine Administration unwirksamer Substanzen erfolgt und eventuell ein Überlebensvorteil für die Patientinnen erzielt werden kann. Die Verkleinerung des Tumors erhöht nicht nur die Rate der brusterhaltenden Therapien, sondern hat Vorhersagewert für den weiteren Krankheitsverlauf. Besonders die pathologische Komplettremission ist ein Surrogatmarker für ein verbessertes Gesamtüberleben und ist das Ziel jedes modernen Protokolls im präoperativen Ansatz. Derzeit laufende Studien (wie zum Beispiel die Studien der Arbeitsgemeinschaft für Gynäkologische Onkologie PREPARE und TECHNO) integrieren moderne Behandlungskonzepte, wie die dosisdichte, dosisintensivierte, sequentielle sowie die zielgerichtete Therapie mit Trastuzumab in die PST. Geeignete Patientinnen sollten in laufende Studien eingebracht werden, um die Rolle der PST bei primärem Mammakarzinom weiter zu untersuchen. Die Evaluation prädiktiver Faktoren und die Korrelation des Therapieansprechens mit dem genetischen Profil des Tumors mittels moderner molekularbiologischer Methoden werden eine verbesserte Patientenselektion mit zunehmend gezielter Therapie ermöglichen.
Photodynamic Therapy of Prostate Cancer by Means of 5-Aminolevulinic Acid-Induced Protoporphyrin IX – In vivo Experiments on the Dunning Rat Tumor Model
Authors: Zaak Dirk , Sroka Ronald , Stocker Susanne , Bise Karl , Lein Michael , Höppner Michael , Frimberger Dominic , Schneede Peter , Reich Oliver , Kriegmair Martin , Knüchel Ruth , Baumgartner Reinhold , Hofstetter Alfons
Published: April 2004

Objective: In order to expand the use of photodynamic therapy (PDT) in the treatment of prostate carcinoma (PCA), the aim of this study was to evaluate PDT by means of 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PPIX) in an in vivo tumor model. Methods: The model used was the Dunning R3327 tumor. First of all, the pharmacokinetics and the localization of PPIX were obtained using fluorescence measurement techniques. Thereafter, PDT using 150 mg 5-ALA/kg b.w. i.v. was performed by homogenous irradiation of the photosensitized tumor (diode laser λ = 633 nm). The tumors were resected 2 days post-PDT and the extent of the necrosis was determined histopathologically. Results: The kinetics of PPIX fluorescence revealed a maximum intensity in the tumor tissue within 3 and 4.5 h post-application of 5-ALA. At this time, specific PPIX fluorescence could be localized selectively in the tumor cells. The PDT-induced necrosis (n = 18) was determined to be 94 ± 12% (range 60–100%), while the necrosis of the controls (n = 12) differs significantly (p < 0.01), being less than 10%. Conclusion: These first in vivo results demonstrate the effective potential of 5-ALA-mediated PDT on PCA in an animal model.
The Patient’s Self-Evaluation Better Predicts the Degree of Erectile Dysfunction than the Response to Intracavernous Alprostadil Testing
Authors: Casella Roberto , Deckart Alexander , Bachmann Alexander , Sulser Tullio , Gasser Thomas C. , Lehmann Kurt
Published: April 2004

Objectives: A modern baseline assessment of erectile dysfunction (ED) should be individualized, reliable, noninvasive and cost-efficient. Appraisal based on the patient’s self-evaluation may be the method of choice. Methods: Using a self-report method, 63 consecutive ED patients were prospectively investigated. Semiquantitative parameters on 7 criteria were assessed, and an intracavernous injection test with alprostadil was performed. Performances of self-reporting and intracavernous testing in predicting penetrative ability were compared. Results: Twenty-three (37%) men had erection insufficient for penetration even with manual assistance, 26 (41%) men needed manual assistance and 14 (22%) could penetrate without manual assistance but erection was not sufficient for satisfaction. In addition to impaired penetrative ability, 6 criteria (intercourse frequency, patient’s and partner’s satisfaction, penile rigidity, duration of erection and need for extra stimulation) deteriorated over time (p < 0.006). Patient self-evaluation criteria such as intercourse per week, patient satisfaction, penile rigidity, duration of erection and time between consultation and last satisfactory intercourse showed discriminating differences in accordance with the 3 subgroups of penetrative ability (p < 0.02). Intracavernous testing could not reproduce the degree of erectile deficit as experienced during intercourse (p = 0.21). In a logistic regression model, criteria best characterizing penetrative ability were penile rigidity, time between consultation and last unsuccessful intercourse, and degree of satisfaction (p < 0.0001). Conclusions: The patient’s self-evaluation by semiquantitative parameters on criteria characterizing sexual erections better predicts the penetrative ability than the response to an intracavernous injection. These criteria quantify both the objective degree of ED and the patient’s apprehension. Consequently, patients may undergo immediate treatment without further testing.
Measurement of Penile Intracavernous Pressure with a Skin Fold Caliper
Authors: Bassas Lluís , Ribé Natalia , Rajmil Osvaldo
Published: April 2004

Objective: We report the use of the skin fold caliper as a simple, noninvasive device for the measurement of penile intracavernous pressure (ICP). Methods: A commercial skin fold caliper (Lange type) was used to evaluate erections produced by intracavernous injections of prostaglandin E1 in 43 patients and to compare ICP with radial rigidity estimation in 13 impotent men undergoing cavernosometry. Calculation of the rigidity index using the skin fold caliper was based on the girth change of the penis shaft when the caliper’s jaws exerted a constant pressure of 10 g/mm2. Results: Measurements of radial rigidity at the base and the midshaft of the penis were closely correlated (r = 0.96). The overall correlation between ICP and the rigidity index (after plotting data on exponential and logarithmic axes, respectively) was good (r = 0.94). The accuracy of the estimated ICP was good at low values and diminished at higher levels. Conclusion: The skin fold caliper can be used for accessible, inexpensive and reproducible single measurements of penile radial rigidity of erections obtained under erotic stimulation in a household environment and for estimates of penile ICP during diagnostic and therapeutic procedures in clinical practice.
Effect of Extratesticular Hematoma on Testicular Blood Flow and the Histology of the Testis and Dartos Fascia
Authors: Caglayan Fatma , Cakmak Murat , Karadeniz Yasemin , Atasoy Pinar , Eroglu Erol , Apan Alpaslan
Published: April 2004

Introduction: Hematoma is a common complication of inguinoscrotal surgery in childhood. We aimed to identify the possible effects of extratesticular hematoma on blood flow and the histology of testes in the early period.Also, the dartos tissue was evaluated histologically. Materials and Methods: Unilateral extratesticular hematoma was created in 12 New Zealand rabbits. Parenchyma of the testes and scrotum walls was evaluated by B-mode ultrasound and the spectrum from the intratesticular vessels was obtained by color Doppler ultrasound on days 1, 7 and 15 of the procedure. Testes and scrotal walls were removed at the end of the study for histologic evaluation. Results: There were no significant pathologic findings in the evaluation of the parenchyma and hemodynamia of the testes on days 1, 7 and 15. A well-organized but continuing hematoma was observed on day 15. Increased fibroblastic activity, dense inflammatory cells, necrotic areas and destruction of the muscular layer were observed at pathologic evaluation of the scrotum. Conclusions: Extratesticular hematoma has no effect on testicular histology and hemodynamia in the early period. Pathologic evaluation revealed fibrosis of the dartos fascia at the end of the second week. Destruction and fibrosis of this tissue may have an adverse effect on spermatogenesis by altering thermoregulation.