bluuebunny/crossref_metadata_2025 huggingface dataset:
Establishment and Maintenance of Gammaherpesvirus Latency Are Independent of Infective Dose and Route of Infection
Authors: Tibbetts Scott A. , Loh Joy , van Berkel Victor , McClellan James S. , Jacoby Meagan A. , Kapadia Sharookh B. , Speck Samuel H. , Virgin Herbert W.
Published: June 2003

Gammaherpesviruses such as Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus are important human pathogens that establish long-term latent infections. Understanding of the initiation and maintenance of latent infections has important implications for the prevention and treatment of gammaherpesvirus-related diseases. Although much is known about gammaherpesvirus pathogenesis, it is unclear how the infectious dose of a virus influences its ability to establish latent infection. To examine the relationship between the infectious dose and gammaherpesvirus latency, we inoculated wild-type mice with 0.01 to 10
6
PFU of murine gammaherpesvirus 68 (γHV68) and quantitatively measured latency and acute-phase replication. Surprisingly, during latency, the frequencies of ex vivo reactivation were similar over a 10
7
-fold range of doses for i.p. infection and over a 10
4
-fold range of doses for intranasal infection. Further, the frequencies of cells harboring viral genome during latency did not differ substantially over similar dose ranges. Although the kinetics of acute-phase replication were delayed at small doses of virus, the peak titer did not differ significantly between mice infected with a large dose of virus and those infected with a small dose of virus. The results presented here indicate that any initiation of infection leads to substantial acute-phase replication and subsequent establishment of a maximal level of latency. Thus, infections with doses as small as 0.1 PFU of γHV68 result in stable levels of acute-phase replication and latent infection. These results demonstrate that the equilibrium level of establishment of gammaherpesvirus latency is independent of the infectious dose and route of infection.
Degradation of phenanthrene and naphthalene by aBurkholderiaspecies strain
Authors: Kang H , Hwang S Y , Kim Y M , Kim E , Kim Y -S , Kim S -K , Kim S W , Cerniglia C E , Shuttleworth K L , Zylstra G J
Published: June 2003

Burkholderia sp. TNFYE-5 was isolated from soil for the ability to grow on phenanthrene as sole carbon and energy source. Unlike most other phenanthrene-degrading bacteria, TNFYE-5 was unable to grow on naphthalene. Growth substrate range experiments coupled with the ring-cleavage enzyme assay data suggest that TNFYE-5 initially metabolizes phenanthrene to 1-hydroxy-2-naphthoate with subsequent degradation through the phthalate and protocatechuate and β-ketoadipate pathway. A metabolite in the degradation of naphthalene by TNFYE-5 was isolated by high-pressure liquid chromatography (HPLC) and was identified as salicylate by UV-visible spectral and gas chromatography  mass spectrometry analyses. Thus, the inability to degrade salicylate is apparently one major reason for the incapability of TNFYE-5 to grow on naphthalene.Key words: Burkholderia, phenanthrene, naphthalene, phthalate, protocatechuate.
TherecXgene product is involved in the SOS response inHerbaspirillum seropedicae
Authors: Galvão Carolina W , Pedrosa Fábio O , Souza Emanuel M , Yates M Geoffrey , Chubatsu Leda S , Steffens Maria Berenice R
Published: June 2003

The recA and the recX genes of Herbaspirillum seropedicae were sequenced. The recX is located 359 bp downstream from recA. Sequence analysis indicated the presence of a putative operator site overlapping a probable σ70-dependent promoter upstream of recA and a transcription terminator downstream from recX, with no apparent promoter sequence in the intergenic region. Transcriptional analysis using lacZ promoter fusions indicated that recA expression increased three- to fourfold in the presence of methyl methanesulfonate (MMS). The roles of recA and recX genes in the SOS response were determined from studies of chromosomal mutants. The recA mutant showed the highest sensitivity to MMS and UV, and the recX mutant had an intermediate sensitivity, compared with the wild type (SMR1), confirming the essential role of the RecA protein in cell viability in the presence of mutagenic agents and also indicating a role for RecX in the SOS response.Key words: Herbaspirillum seropedicae, recA gene, recX gene, DNA repair, SOS mutagenesis.
Effect of genotype and root colonization in biological control of fusarium wilts in pigeonpea and chickpea byPseudomonas aeruginosaPNA1
Authors: Anjaiah Vanamala , Cornelis Pierre , Koedam Nico
Published: June 2003

Pseudomonas aeruginosa PNA1, an isolate from chickpea rhizosphere in India, protected pigeonpea and chickpea plants from fusarium wilt disease, which is caused by Fusarium oxysporum f.sp. ciceris and Fusarium udum. Inoculation with strain PNA1 significantly reduced the incidence of fusarium wilt in pigeonpea and chickpea on both susceptible and moderately tolerant genotypes. However, strain PNA1 protected the plants from fusarium wilt until maturity only in moderately tolerant genotypes of pigeonpea and chickpea. Root colonization of pigeonpea and chickpea, which was measured using a lacZ-marked strain of PNA1, showed tenfold lower root colonization of susceptible genotypes than that of moderately tolerant genotypes, indicating that this plantbacteria interaction could be important for disease suppression in this plant. Strain PNA1 produced two phenazine antibiotics, phenazine-1-carboxylic acid and oxychlororaphin, in vitro. Its Tn5 mutants (FM29 and FM13), which were deficient in phenazine production, caused a reduction or loss of wilt disease suppression in vivo. Hence, phenazine production by PNA1 also contributed to the biocontrol of fusarium wilt diseases in pigeonpea and chickpea.Key words: biocontrol, fusarium wilts, phenazines, Pseudomonas.
Utilization of monocrotophos as phosphorus source byPseudomonas aeruginosaF10B andClavibacter michiganensesubsp.insidiosumSBL 11
Authors: Subhas  , Singh Dileep Kumar
Published: June 2003

Monocrotophos (dimethyl (E)-1-methyl-2-(methylcarbamoyl) vinyl phosphate, or MCP), an organophosphorus insecticide, was used as a sole phosphorus source by the microorganisms isolated from the soil. None of the isolates could utilize MCP as a sole source of carbon. Two of the potential microbial isolates, Pseudomonas aeruginosa F10B and Clavibacter michiganense subsp. insidiosum SBL 11, could utilize MCP as a sole source of phosphorus. Pseudomonas aeruginosa F10B showed a lag phase of 4 h, while in the case of C. michiganense subsp. insidiosum SBL 11, it was 8 h when cultured in the presence of MCP. The generation time for both strains was increased in the medium containing MCP. It was 2.15 h for P. aeruginosa F10B in MCP medium as compared with 1.29 h in basal medium, while in case of C. michiganense subsp. insidiosum SBL 11 it was increased to 3.4 h in MCP medium as compared with 1.28 h in basal medium. These two strains were able to degrade technical MCP in shake-flask culture up to 98.9 and 86.9%, respectively, and pure MCP up to 79 and 80%, respectively, within 24 h at 37°C. The optimal concentration of MCP required for the normal growth was 500 ppm. In the substrate preference study, Trisp-nitrophenyl phosphate was the most preferred substrate followed by paraoxon. The enzyme responsible for the break down of MCP was phosphotriesterase, which was localized on the membrane-bound fraction of the disrupted cells. The gene responsible for the production of phosphotriesterase (opd) in P. aeruginosa F10B was plasmid-borne.Key words: biodegradation, monocrotophos, phosphotriesterase, P. aeruginosa, C. michiganense subsp. insidiosum.
Low-level iron-dependent mutants ofListeria monocytogenesand their virulence in macrophages
Authors: Andre Philippe , Oberle Stéphanie , Specklin Véronique , Lombard Yves , Vidon Dominique Jean-Marie
Published: June 2003

Listeria monocytogenes is an opportunistic intracellular pathogen capable of growth within phagocytic cells that requires iron for growth and virulence expression. In the presence of an appropriate concentration of tropolone, an iron-chelating agent, growth of L. monocytogenes is completely inhibited. However, this inhibition can be relieved by addition of dopamine, norepinephrine, or ferric citrate. By selection on streptonigrin medium supplemented with tropolone and norepinephrine, we have obtained two spontaneous mutants, Lm-8 and Lm-15, with the same iron dependence but lower iron dependence than the wild-type Lm-B38. The association between iron requirement and virulence of the two mutants and the wild type was studied in the J774 macrophage cell line. One hour after phagocytosis by the J774 macrophage cell line, the two mutants and the parental strain displayed no difference in the number of phagocytosed bacteria. Twenty-four hours after phagocytosis, the number of bacteria within the surviving macrophages was identical for the wild strain and the two clones. However, only 40% of macrophage cells infected with Lm-8 and 90% of those infected with Lm-15 were alive after 24 h in comparison with macrophage cells infected with the parental strain Lm-B38. These data demonstrate that there is no direct correlation between iron requirement and virulence of L. monocytogenes in the J774 macrophage cell line.Key words: Listeria monocytogenes, iron, virulence, macrophages.
Isolation and taxonomic and catabolic characterization of a 3,6-dimethylphenanthrene-utilizing strain ofSphingomonassp.
Authors: Sabaté J , Viñas M , Bayona J M , Solanas A M
Published: June 2003

A bacterial strain capable of utilizing 3,6-dimethylphenanthrene (3,6-DMP) as its sole source of carbon and energy was isolated from a creosote-contaminated soil. The isolate was identified as a strain of Sphingomonas sp. and was designated strain JS1. Utilization of 3,6-DMP was demonstrated by an increase in bacterial biomass concomitant with a decrease in 3,6-DMP in a liquid mineral medium with this compound as its sole source of carbon and energy. Strain JS1 showed a high specificity in the use of the most abundant alkylderivatives of crude oils, such as alkylnaphthalenes and other alkylphenanthrenes, as the sole source of carbon and energy. It can also use several polycyclic aromatic hydrocarbons of three and four rings and their alkylated derivatives as growth substrates or transform them. The identification of several intermediate metabolites points to extensive metabolic activity, including the following: (i) aromatic ring oxidation and cleavage, (ii) methyl group oxidations, and (iii) methylenic oxidations. The metabolic actions of Sphingomonas sp. JS1 on the aromatic fraction extracted from a creosote-contaminated soil are also examined.Key words: dimethylphenanthrene, alkylated PAHs, biodegradation, Sphingomonas.
Thermoregulation in the cold after physical training at different ambient air temperatures
Authors: Launay Jean-Claude , Besnard Yves , Guinet Angélique , Hanniquet Anne-Marie , Bittel Jacques , Savourey Gustave
Published: June 2003

Since human thermoregulation at rest is altered by cold exposure, it was hypothesized that physical training under cold conditions would alter thermoregulation. Three groups (n = 8) of male subjects (mean age 24.3 ± 0.9 years) were evaluated: group T (interval training at 21°C), group CT (interval training at 1°C), and group C (no training, equivalent exposure to 1°C). Each group was submitted, before and after 4 weeks of interval training (5 d/week), to a cold air test at rest (SCAT) (dry bulb temperature (Tdb) = 1°C) for a 2-h period for evaluation of the thermoregulatory responses. During SCAT, after the training/acclimation period, group T exhibited a higher rectal temperature (Tre) (P < 0.05) without significant change in mean skin temperature (Tbarsk) whereas metabolic heat production (Mdot) was higher at the beginning of the SCAT (P < 0.05). For group CT, no thermoregulatory change was observed. Group C showed a lower Tre (P < 0.05) without significant change in either Tbarsk or in Mdot, suggesting the development of a hypothermic general cold adaptation. This study showed, first, that the cold thermoregulatory responses induced by an interval training differed following the climatic conditions of the training and, second, that this training performed in the cold prevented the development of a general cold adaptation.Key words: physical training, cold tolerance, general cold adaptation, human, thermoregulation.
COVARIANT MATRIX MODEL OF SUPERPARTICLE IN THE PURE SPINOR FORMALISM
Authors: ODA ICHIRO
Published: June 2003

On the basis of the Berkovits pure spinor formalism of covariant quantization of supermembrane, we attempt to construct a M(atrix) theory which is covariant under SO(1, 10) Lorentz group. We first construct a bosonic M(atrix) theory by starting with the first-order formalism of bosonic membrane, which precisely gives us a bosonic sector of M(atrix) theory by BFSS. Next we generalize this method to the construction of M(atrix) theory of supermembranes. However, it seems to be difficult to obtain a covariant and supersymmetric M(atrix) theory from the Berkovits pure spinor formalism of supermembrane because of the matrix character of the BRST symmetry. Instead, in this paper, we construct a supersymmetric and covariant matrix model of 11D superparticle, which corresponds to a particle limit of covariant M(atrix) theory. By an explicit calculation, we show that the one-loop effective potential is trivial, thereby implying that this matrix model is a free theory at least at the one-loop level.
SELECTED TOPICS IN PLANCK-SCALE PHYSICS
Authors: NG Y. JACK
Published: June 2003

We review a few topics in Planck-scale physics, with emphasis on possible manifestations in relatively low energy. The selected topics include quantum fluctuations of spacetime, their cumulative effects, uncertainties in energy–momentum measurements, and low energy quantum-gravity phenomenology. The focus is on quantum-gravity-induced uncertainties in some observable quantities. We consider four possible ways to probe Planck-scale physics experimentally: (i) looking for energy-dependent spreads in the arrival time of photons of the same energy from GRBs; (ii) examining spacetime fluctuation-induced phase incoherence of light from extragalactic sources; (iii) detecting spacetime foam with laser-based interferometry techniques; (iv) understanding the threshold anomalies in high energy cosmic ray and gamma ray events. Some other experiments are briefly discussed. We show how some physics behind black holes, simple clocks, simple computers, and the holographic principle is related to Planck-scale physics. We also discuss a formulation of the Dirac equation as a difference equation on a discrete Planck-scale spacetime lattice, and a possible interplay between Planck-scale and Hubble-scale physics encoded in the cosmological constant (dark energy).
LAST CPT-INVARIANT HOPE FOR LSND NEUTRINO OSCILLATIONS
Authors: GIUNTI C.
Published: June 2003

It is shown that the 99% confidence limits from the analyses of the data of cosmological and neutrino experiments imply a small marginally allowed region in the space of the neutrino oscillation parameters of 3 + 1 four-neutrino mixing schemes. This region can be confirmed or falsified by experiments in the near future.
AN ADAPTIVE METHOD FOR EVALUATING MULTIDIMENSIONAL CONTINGENT CLAIMS: PART II
Authors: DAHL LARS O.
Published: June 2003

This is part two of a work on adaptive integration methods aimed at multidimensional option pricing problems in finance. It presents simulation results of an adaptive method developed in the companion article [3] for the evaluation of multidimensional integrals over the unit cube. The article focuses on a rather general test problem constructed to give insights in the success of the adaptive method for option pricing problems. We establish a connection between the decline rate of the ordered eigenvalues of the pricing problem and the efficiency of the adaptive method relative to the non-adaptive. This gives criteria for when the adaptive method can be expected to outperform the non-adaptive for other pricing problems. In addition to evaluating the method for different problem parameters, we present simulation results after adding various techniques to enhance the adaptive method itself. This includes using variance reduction techniques for each sub-problem resulting from the partitioning of the integration domain. All simulations are done with both pseudo-random numbers and quasi-random numbers (low discrepancy sequences), resulting in Monte Carlo (MC) and quasi-Monte Carlo (QMC) estimators and the ability to compare them in the given setting. The results show that the adaptive method can give performance gains in the order of magnitudes for many configurations, but it should not be used incautious, since this ability depends heavily on the problem at hand.
PORTFOLIO OPTIMIZATION OF SMALL SCALE FUND USING MEAN-ABSOLUTE DEVIATION MODEL
Authors: KONNO HIROSHI
Published: June 2003

The purpose of this paper is to show that we are now able to apply standard portfolio optimization methods to the management of small and medium scale fund, where transaction cost and minimal transaction unit constraints are not negligible.

Unit transaction cost is usually larger when the amount of investment is smaller. Also, rounding of portfolio to the nearest integer multiple of minimal transaction unit will have non negligible effect on the risk-return structure of the portfolio.

We will show that the use of mean-absolute deviation model enables one to handle concave transaction cost and minimal transaction unit constraints in an efficient manner using branch and bound algorithm. Also, we will show that the minimal transaction cost rebalancing problem can be solved by using the same algorithm.
Introduction to two-dimensional X-ray diffraction
Authors: He Bob Baoping
Published: June 2003

Two-dimensional X-ray diffraction refers to X-ray diffraction applications with two-dimensional detector and corresponding data reduction and analysis. The two-dimensional diffraction pattern contains far more information than a one-dimensional profile collected with the conventional diffractometer. In order to take advantage of two-dimensional diffraction, new theories and approaches are necessary to configure the two-dimensional X-ray diffraction system and to analyze the two-dimensional diffraction data. This paper is an introduction to some fundamentals about two-dimensional X-ray diffraction, such as geometry convention, diffraction data interpretation, and advantages of two-dimensional X-ray diffraction in various applications, including phase identification, stress, and texture measurement.
Age-Related Changes in Pharmacokinetics and Pharmacodynamics of Lerisetron in the Rat: A Population Pharmacokinetic Model
Authors: Jauregizar Nerea , Quintana Antonio , Suarez Elena , Raczka Ewa , De la Fuente Leire , Calvo Rosario
Published: June 2003

Background: The importance of studying the effects of age on the pharmacokinetics and pharmacodynamics of lerisetron – a new 5-hydroxytryptamine-3 (serotonin) receptor antagonist – comes from the facts that lerisetron will be administered to patients that are being treated with cytotoxic drugs and that the elderly frequently suffer from neoplastic diseases. Objective: The present study was designed to explore the effects of age on the pharmacokinetics and pharmacodynamics of lerisetron by using an aged rat model. A mixed-effects population study was carried out in order to analyze the sparse data and to create covariate models which could be used to derive dosage recommendations. Methods: Fischer 344 rats (n = 44) were divided into three groups, depending on their age: 5, 13, and 25 months. Blood samples were collected before administration of 200 µg/kg of lerisetron for measurements of albumin, α1-acid glycoprotein, and unbound fraction of lerisetron. The lerisetron plasma concentrations were measured by high-performance liquid chromatography. A two-compartment model was fitted to the data using the nonlinear mixed-effects computer program WinNonMix. The population analysis was performed with the complete set of the collected data, and the potential sources of variability in the population parameters were investigated. Additionally, a pharmacodynamic study was performed. The effect of lerisetron (inhibition of the von Bezold-Jarisch reflex) was evaluated in young, adult, and senescent Fischer 344 rats. Results: The mean values of the individual Bayes estimates of the parameters showed a decrease in total clearance and distribution volume of the central compartment in old rats. The lerisetron free (unbound) fraction remained unchanged among the groups, and there were no significant differences in α1-acid glycoprotein levels. The concentration-effect relationship was best described by a sigmoid Emax model. Since the drug concentration in plasma at half-maximal effect (EC50) decreased in old rats, an increased sensitivity to the effect of lerisetron in old animals could be expected. Conclusion: Both pharmacokinetic changes (decreased volume of distribution and clearance and increased elimination half-life) and pharmacodynamic alterations (decrease in total and unbound EC50) may be responsible for the different responses to lerisetron observed in old rats.
Impact of Pneumococcal Vaccination on Morbidity and Mortality of Geriatric Patients: A Case-Controlled Study
Authors: Wagner Christian , Popp Wolfgang , Posch Martin , Vlasich Clemens , Rosenberger-Spitzy Angelika
Published: June 2003

Background: Infections due to Streptococcus pneumoniae are the major cause of adult community-acquired pneumonia, especially in elderly persons with chronic medical conditions. Despite their well-documented efficacy against bacteraemic disease and deaths in the elderly population, pneumococcal polysaccharide vaccines are still very much underused. Objective: A retrospective, case-controlled study was performed to investigate the impact of vaccination with a polysaccharide pneumococcal vaccine, together with other risk factors, on the incidence of pneumonia and deaths in patients in a long-stay geriatric hospital. Methods: Subjects were 1,077 residents in a long-stay geriatric hospital in Vienna, Austria, including 359 patients diagnosed as having pneumonia during the period from July 1996 to October 1998 and 718 control subjects. Two controls resident in the hospital during the same time period were matched for each case according to demographic characteristics, chronic illness, and duration of stay in the geriatric ward. The vaccination status was established for all subjects. A logistic regression analysis was performed to assess the efficacy of vaccination and the impact of other cofactors on disease and death. Results: In cases and controls, 514 (47.7%) had received a pneumococcal vaccine within 2 years prior to the study. There were no differences in demographic characteristics, underlying medical conditions, or duration of stay in the hospital between vaccinated and non-vaccinated patients. In patients diagnosed with pneumonia, 66% were unvaccinated. Logistic regression analysis showed that vaccination significantly decreased the risk of pneumonia (odds ratio 0.279; p < 0.0001). Of the cofactors tested, only gender (lower risk in males) and diabetes mellitus (higher risk) had any impact on disease risk and vaccine efficacy. There appeared to be a highly significant effect of vaccination, reducing the risk of all deaths (odds ratio 0.269; p < 0.0001) and deaths due to pneumonia (odds ratio 0.331; p < 0.0001). Conclusion: This study showed that vaccination with a polysaccharide pneumococcal vaccine is effective in all groups of geriatric subjects and has a consequential value for health and well-being of elderly institutionalized patients.
An Evidence-Based Medicine Approach to the Evaluation of the Role of Exogenous Risk Factors in Sporadic Amyotrophic Lateral Sclerosis
Authors: Armon Carmel
Published: June 2003

An evidence-based medicine approach was applied to evaluate analytic studies of exogenous risk factors for amyotrophic lateral sclerosis (ALS) published since 1991. Classification systems for evaluating the literature and for drawing conclusions based on the class of available evidence were developed, modeled on those used by national societies. Considerations regarding the impact on the general public of confirming a role for putative risk factors were made explicit. There was evidence in support of smoking being a probable (‘more likely than not’) risk factor for ALS. Smoking has broad public health impact, no redeeming features, and is a modifiable risk factor. Evidence supported the conclusion that the following were probably not risk factors for ALS: trauma, physical activity, residence in rural areas and alcohol consumption. Evidence-based medicine methodology does not permit calculation of the magnitude of type I or type II errors in drawing these conclusions. New evidence may change these conclusions. Recommendations for future research include: draw on clinical trial methodology in designing future, confirmatory, case-control studies; consider utilizing cohort studies, recognizing the longer timelines for these to come to fruition; accord priority to investigating putative risk factors with greatest public health impact. Advances in study methodology may lead to development of finite research cycles for individual putative risk factors for sporadic ALS.
A Descriptive Study of Guillain-Barré Syndrome in High and Low Campylobacter jejuni Incidence Regions of Michigan: 1992–1999
Authors: Church Potter Rachel , Kaneene John B.
Published: June 2003

The incidence rate of Guillain-Barré syndrome (GBS) was compared between high and low Campylobacter jejuni incidence counties in Michigan, USA, between 1992 and 1999. Data on GBS was obtained from cases reported to the Michigan Department of Community Health. Poisson confidence intervals were used to compare incidence rates. There was no significant difference in the overall rate between high and low C. jejuni incidence regions in Michigan. Though no differences in age-specific, gender-specific, and seasonal rates were significant, GBS was more common in spring and summer in the high C. jejuni incidence region than in the low C. jejuni incidence region. Differences in the distribution of cases by age group and gender are described, though no difference was statistically significant.
Analgesic Effect of Elastoviscous Hyaluronan Solutions and the Treatment of Arthritic Pain
Authors: Balazs Endre A.
Published: June 2003

Elastoviscous hyaluronan solutions have an analgesic effect when injected intra-articularly in animal and human joints. This was first discovered using animal behavioral models and later confirmed in neurophysiological studies in cat and rat joints. These studies on both normal and experimentally produced arthritis in joints confirmed that only elastoviscous solutions of hyaluronan or certain of its derivatives (hylans) have a desensitizing effect on nociceptive sensory receptors. Recently, this desensitizing effect of elastoviscous hyaluronan solutions was also demonstrated on intact or on isolated patches of oocyte cell membranes. Viscosupplementation, the exchange of pathological synovial fluid in arthritic joints with pure elastoviscous solutions of hyaluronan or hylans, is a widely accepted therapeutic modality used to provide long-lasting analgesia in human knee joints. The clinical studies performed on human and animal temporomandibular joints since the mid-1970s are reviewed. These trials used three distinctly different preparations made from hyaluronan of different average molecular weight, polydispersity and, consequently, different elastoviscous properties. These differences are demonstrated and the consequences on the potential efficacy of the preparations are discussed.
Experimental Study Using PTFE (Goretex) Patches for Replacement of the Oesophageal Wall
Authors: González Sáez L.A. , Arnal Monreal F. , Pita Fernández S. , Machuca Santa Cruz J.
Published: June 2003

Background: The purpose of this study was to evaluate tolerance and integration of expanded polytetrafluoroethylene patches used to replace loss of a fragment of the complete oesophageal wall in rats of the Wistar strain. Methods: The experiment was performed on 10 Wistar rats. Those surviving the experiment were killed 7–28 days after surgery. Results: None of these animals showed signs of peritonitis. The patch was not visible macroscopically. After examination under the microscope, we observed that the material had undergone phagocytosis by macrophages, and there was scar tissue covering the epithelium. Conclusion: It is possible to successfully suture a polytetrafluoroethylene patch to the oesophageal wall in Wistar rats as a prosthetic replacement of a wall fragment.
‘On-Line’ Alterations of Contralateral Jugular Blood Gas Profile during Carotid Clamping
Authors: Vretzakis G. , Papadimitriou D. , Papaziogas B. , Koutsias S. , Christopoulos D. , Ferdi E. , Papadopoulos G.
Published: June 2003

The aim of this work was to record the metabolic status of the brain (pH, PCO2 and PO2) during carotid endarterectomy (CEA), with the use of an intravascular multiparameter sensor (Paratrend 7) via retrograde catheterization of the contralateral jugular vein. Twenty-four patients with ASA grades II and III scheduled for CEA were included in the study. After induction of anesthesia, the contralateral internal jugular vein was punctured retrogradely and the sensor was introduced. During clamping, pH became persistently more acidotic (7.34–7.31; p < 0.05), PCO2 was elevated (43.2–46.8 mm Hg; p < 0.05) while most of the patients showed a non-significant decrease in PjvO2/SjvO2 (jv = jugular venous). Correlation with clamping time or stump pressure was not significant. Unclamping was followed by a short period (5– 9 min) of decrease in pH and elevation of PCO2 (7.30–7.22; p < 0.05, and 48.0–52.5 mm Hg; p < 0.05, respectively). PjvO2 was significantly elevated (51.8–58.0 mm Hg; p < 0.001) after the restoration of flow. The study suggests that local CO2 creates conditions for compensation of flow after the application of a carotid clamp. We consider that this monitoring technique, after further validation, may provide useful information.
Omental Transposition Decreases Ischemic Brain Damage Examined in a New Ischemia Model
Authors: Vatansev C. , Üstün M.E. , Öğün C.Ö. , Taştekin G. , Karabacakoğlu A. , Yilmaz H.
Published: June 2003

Purpose: The aim of this study was to determine whether omental transposition at the time of focal cerebral ischemia can decrease ischemic brain damage produced in dogs, in a new ischemia model, which had been described by us. Methods: In group 1 (n = 5), the left internal carotid artery and arterial circle of the brain (posterior communicating artery in humans) were occluded permanently. In group 2 (n = 5), additionally to this ischemia model, omental transposition was performed simultaneously. In the postoperative early period (first 24 h), single photon emission computed tomography (SPECT) and in the late period (72–96 h) SPECT and magnetic resonance imaging (MRI) of the brain were performed. Mann-Whitney U, paired t and Wilcoxon signed rank tests were used for statistical analyses, and p < 0.05 was considered significant. Results: The dogs had a neurological score (NS) of 3.6 ± 0.5 and 3.4 ±0.5 in groups 1 and 2, respectively, in the early period (p > 0.05). In the late period, the dogs had an NS of 4.4 ± 0.5 and 5.6 ± 0.5 in groups 1 and 2, respectively (p < 0.05). The NS of each group differed significantly between the early and late period (p < 0.05). Early SPECT imaging showed 50 ± 7.0% and 52 ± 8.4% hypoperfusion corresponding to the left middle cerebral artery territory in groups 1 and 2, respectively (p > 0.05). In the late period, the degree of hypoperfusion decreased to 34 ± 5.5% and 12 ± 4.8% in groups 1 and 2, respectively (p < 0.05). The degree of hypoperfusion in both groups changed significantly between the early and late period (p < 0.05). In T1- and T2-weighted MRI images, the volume of the lesion in group 1 was significantly greater than in group 2 (p < 0.001). Conclusion: In our new ischemia model, simultaneous omental transposition is helpful in reversing the neurologic deficit and cerebral ischemic damage.
Effects of Nasal Calcitonin on Bone Mineral Density following Parathyroidectomy in Patients with Primary Hyperparathyroidism
Authors: Casez J.-P. , Tschopp P. , Sandberg Tschopp A. , Lippuner K. , Zingg E. , Jaeger P.
Published: June 2003

Aim: To investigate whether nasal salmon calcitonin (CT; 200 U/day) given in addition to calcium helps to restore the bone mass after parathyroidectomy (PTX) in patients with primary hyperparathyroidism (PHPT). Methods: Twenty patients with PHPT were enrolled after successful PTX and received 1 g calcium per os daily for 1 year. They were randomly assigned either to nasal CT (CT group) or to no treatment. The bone mass was measured using dual-energy X-ray absorptiometry at multiple sites. Results: Eight patients in each group completed the study. After 12 months, the bone mass increased significantly at whole-body level and at lumbar spine in both groups, increased at hip and epiphyses of tibia or radius in the CT group only, and did not change at diaphyses of tibia and radius in either group. Conclusions: Bone mass increases after PTX for PHPT in patients receiving oral calcium. CT may help to restore the bone mass at sites of the appendicular skeleton, where trabecular bone predominates.
A New Mutation of 5-Alpha-Reductase Type 2 (A62E) in a Large Egyptian Kindred
Authors: Hafez Mona , Mazen Inas , Ghali Isis , Sultan Charles , Lumbroso Serge
Published: June 2003

Objective: To describe the clinical, biological and molecular data in a large Egyptian kindred with 5α-reductase deficiency. Patients and Methods: Three patients with ambiguous genitalia were referred at the ages of 20, 9 and 2 years, respectively. In all cases, parents were first cousins. Basal and post-HCG stimulation plasma levels of testosterone and dihydrotestosterone were determined. Direct sequencing and restriction site analysis were applied for patient and family study. Results: A homozygous alanine to glutamic acid substitution at position 62 (A62E) was found in the three patients. The parents and two XX sisters were heterozygous while a third XX sibling was normal. Conclusion: We report a new mutation of the 5α-reductase type 2 gene. The presence of this mutation in all studied patients and their parents suggests its causative role in 5α-reductase deficiency. Identification of the mutation enabled genetic counselling for three XX individuals.
The Serum Cortisol:Cortisone Ratio in the Postoperative Acute-Phase Response
Authors: Vogeser M. , Groetzner J. , Küpper C. , Briegel J.
Published: June 2003

Objective: In a previous cross-sectional pilot investigation, an increase in the ratio of active cortisol to inactive cortisone in serum has been found as a general phenomenon during the acute-phase response. The aim of the present study was to further characterize this alteration of cortisol metabolism in patients undergoing elective cardiac bypass surgery. Methods: Cortisol and cortisone were quantified by use of liquid-chromatography tandem mass spectrometry in sera that were sampled preoperatively and on the first 4 postoperative days (POD) from 16 patients undergoing aortocoronary bypass grafting (7.00 a.m.). Results: The median serum cortisol concentration peaked on the first POD and then decreased statistically significantly until the end of the observation period: preoperatively, 245 nmol/l (IQR 198–331); 1st POD, 532 nmol/l (IQR 409–678 ); 4th POD, 373 nmol/l (IQR 306–493); p for trend = 0.019. In contrast, the cortisol:cortisone ratio was constantly increased approximately twofold on all POD compared to preoperative sampling: preoperatively, 5.4 (IQR 5.0–7.2); 1st POD, 11.3 (IQR 9.2–13.6); 4th POD, 9.9 (IQR 7.7–11.0), with no significant trend of normalization. Conclusion: Following major surgery, the substantial increase in the serum cortisol:cortisone ratio – reflecting a shift in the overall set-point of 11β-hydroxysteroid dehydrogenase activity – is more sustained than the increase in serum cortisol; the increase in the cortisol:cortisone ratio seems to be a long-term phenomenon of the activation of the hypothalamic-pituitary-adrenocortical system by surgical stress and systemic inflammation.
Unaltered Plasma Levels of β-Amyloid(1–40) and β-Amyloid(1–42) upon Stimulation of Human Platelets
Authors: Olsson Annika , Vanmechelen Eugeen , Vanderstichele Hugo , Davidsson Pia , Blennow Kaj
Published: June 2003

Accumulation of β-amyloid (Aβ) in the brain is one of the central lesions in Alzheimer’s disease (AD). Alternative cleavage of the amyloid precursor protein (APP), occurring in both normal and AD subjects, results in the generation and secretion of soluble APP, Aβ40 and Aβ42. Platelets have been regarded as the primary source of circulating APP and Aβ. Plasma levels of Aβ may therefore be dependent on platelet activation. We analysed Aβ40/42 in plasma in the presence of physiological agonists of platelet activation such as adenosine diphosphate, collagen, thrombin, and a synthetic agonist, thrombin receptor activator peptide 6. We found that the levels of Aβ40/42 in plasma were not related to platelet activation, suggesting that sampling techniques affecting platelet activation do not confound measurement of Aβ40/42 in plasma.
Antioxidant and Oxidative Stress Indices in Dialysis-Dependent Acute Renal Failure
Authors: Balakrishnan Vaidyanathapuram S. , Blumberg Jeffrey , Pereira Brian J.G. , Jaber Bertrand L.
Published: June 2003

Background: Experimental animal models and in vitro studies have established a role for reactive oxygen species and the therapeutic potential for free radical scavengers in acute renal failure (ARF). Little is known of the effects of hemodialysis and other clinical variables on antioxidant defenses and oxidative stress among patients with ARF. Methods: We examined antioxidant defenses and oxidative stress status in 24 patients with ARF requiring hemodialysis (HD). Blood samples were drawn prior to the first dialysis session (baseline), as well as before and after the third and sixth dialysis sessions. At each time point, the following parameters were measured: plasma α-tocopherol (vitamin E), plasma glutathione peroxidase (GSH-Px), serum total oxygen radical absorbance capacity (ORAC), plasma thiobarbituric acid reactive substances (TBARS), plasma tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10). Multivariate linear regression analyses were performed to examine clinical/laboratory variables associated with antioxidant/oxidative stress indices. The changes in antioxidant/oxidative stress indices over time after initiation of hemodialysis was evaluated in a subgroup of patients (n = 11) who completed six dialysis sessions. Intradialytic changes in antioxidant/oxidative stress indices and the differential impact of cellulose acetate vs. polysulfone dialyzers were also evaluated. Results: Factors associated with α-tocopherol level were serum albumin (301 µg/dl ↑ for each 1 g/dl ↑ in albumin) and ORAC (188 µg/dl ↑ for each 1,000 µmol Trolox Eq/l ↑ in ORAC). Age was independently associated with plasma GSH-Px levels (55 U/l ⇓ for each 10-year age ↑ ). Factors associated with ORAC were α-tocopherol (85 µmol Trolox Eq/l ↑ for each 100 µg/dl ↑ in α-tocopherol) and total bilirubin (30 µmol Trolox Eq/l ⇓ for each 1 mg/dl ↑ in total bilirubin). Total bilirubin was independently associated with TBARS (0.2 µM ↑ for each 1 mg/dl ↑ in total bilirubin). GSH-Px and ORAC levels declined over time between baseline and the sixth dialysis session (p < 0.05 for both). Finally, there was a significant intradialytic decline in ORAC levels, which appeared to be more pronounced with use of cellulose acetate compared with polysulfone dialyzer membranes (p < 0.05). Conclusions: These observations indicate that antioxidant and oxidative stress indices in ARF patients are associated with several clinical and laboratory variables as well as the dialysis procedure. Further studies are needed to investigate the therapeutic role of anti-oxidant therapy in these patients.
A Switch to High-Flux Helixone® Membranes Reverses Suppressed Interferon-γ Production in Patients on Low-Flux Dialysis
Authors: Lonnemann Gerhard , Novick Daniela , Rubinstein Menachem , Passlick-Deetjen Jutta , Lang Dietmar , Dinarello Charles A.
Published: June 2003

Long-term hemodialysis (HD) induces an inflammatory response and is associated with a suppressed cellular immune response manifested, in part, by impaired interferon (IFN-γ) production. We investigated the effect of high-flux HD using the synthetic Helixone® membrane and ultrafiltered dialysate on plasma levels of inflammatory mediators and on the whole blood production of IFN-γ. Methods: Twelve ESRD patients were dialyzed under low-flux HD (polysulfone F6) and again after 6 weeks of high-flux HD (Helixone® FX100). Ultrafiltered bicarbonate dialysate without bacterial growth and no detectable endotoxin was used throughout the study. Plasma levels of urea, albumin, β2-microglobulin (β2-m), interleukin (IL)-6, C-reactive protein (CRP), IL-1 receptor antagonist (IL-1Ra), IL-18, and IL-18-binding protein (IL-18BP) were measured. In addition, the Staphylococcus epidermidis-induced production of IFN-γ and IL-18 was assessed in whole blood cultures of HD patients as well as in 9 healthy subjects. Results: Plasma levels of urea, albumin, IL-6, IL-1Ra and CRP were not significantly different between high-flux and low-flux HD. In contrast, β2-m levels decreased significantly by 31% with high-flux Helixone® (p < 0.002). Stimulated whole blood production of IFN-γ was reduced in low-flux HD but increased to near normal levels after 6 weeks of high-flux HD. Plasma levels of free IL-18 and its specific inhibitor IL-18BP were not different between the two dialyzer membranes. Conclusion: Compared to low-flux polysulfone HD with ultrafiltered dialysate, high-flux HD with the synthetic Helixone® membrane did not result in a significant change in plasma levels of proinflammatory (IL-6, CRP, IL-18) and anti-inflammatory (IL-1Ra, IL-18BP) cytokines. However, high-flux HD restores whole blood IFN-γ production without significant changes in free IL-18. Therefore, the immune modulation in high-flux HD is likely due to removal of inhibitors of IFN-γ production other than IL-18BP.
Detoxifying Capacity and Kinetics of the Molecular Adsorbent Recycling System
Authors: Evenepoel Pieter , Maes Bart , Wilmer Alexander , Nevens Frederik , Fevery Johan , Kuypers Dirk , Bammens Bert , Vanrenterghem Yves
Published: June 2003

The molecular adsorbent recycling system (MARS) represents a cell-free, extracorporeal, liver assistance method for the removal of both albumin-bound and water-soluble endogenous toxins. The aim of the present study was to evaluate the short- and long-term removal capacity and selectivity of the different inbuilt dialysers and adsorption columns (uncoated charcoal, anion exchanger resin). Levels of endogenous toxins and parameters of hepatic synthesis and necrosis were therefore monitored before, during and after the MARS treatment phase in 10 patients. Moreover, blood and dialysate clearances of urea, creatinine, bilirubin and bile acids were determined during a single treatment. The significant increasing time course of total bilirubin blood levels before the start of the treatment could be stopped and reversed in a significant decreasing time course. The removal rates of urea nitrogen, bilirubin and bile acids during a single treatment amounted to 55.5 ± 4.0, 28.3 ± 3.9, and 55.4 ± 4.0% (mean ± SEM), respectively. The efficacy of removal of albumin-bound toxins sharply declined early after initiation of the treatment to become negligible after 6 h. In conclusion, both albumin-bound and water-soluble toxins are adequately removed by the MARS. Our data suggest that the rate and efficacy of removal of albumin-bound toxins are related to both the strength of the albumin binding and the saturation of the adsorption columns.
Arginine Vasotocin Interacts with the Social Environment to Regulate Advertisement Calling in the Gray Treefrog (Hyla versicolor)
Authors: Trainor Brian C. , Rouse Kathryn L. , Marler Catherine A.
Published: June 2003

Arginine vasotocin (AVT) has different effects on social behaviors across species with different social systems. However, less attention has been directed towards the way environmental stimuli interact with AVT to affect social behaviors. Previous work found that AVT affects the production of advertisement calls and the outcome of competitive interactions between male gray treefrogs (Hyla versicolor). We conducted a field study to investigate how the presence of other males in a chorus influenced the production of advertisement calls in males treated with AVT or saline. After hormone treatment we placed individuals in call sites either within 50 cm of another calling male (proximate), or more than 2 m away from any calling male (distant). Males treated with AVT produced significantly longer calls with more pulses when placed at proximate call sites, but not distant call sites. Nonsignificant trends indicated that these increases in call length coincided with a decrease in call rate. There was no effect of call site distance on advertisement calls when males were treated with saline. These results indicate that the social environment can modulate the action of AVT on an important reproductive behavior, and that AVT does not influence call duration and pulse number unless another male is nearby. Understanding how social stimuli regulate the action of AVT on behavior could provide insight on the diversity of AVT function across species.
Structure and Function of Visual Displays Produced by Male Jacky Dragons, Amphibolurus muricatus, during Social Interactions
Authors: Watt Michael J. , Joss Jean M.P.
Published: June 2003

Many lizards produce visual displays to mediate social behavior. However, most studies have focused upon displays used by iguanid lizards. We investigated and quantified the displays used by jacky dragons, an agamid lizard from southeastern Australia. By establishing male jacky dragons within individual territories and conducting experimental presentations of male and female intruders, we were able to demonstrate that territorial male Amphibolurus muricatus utilize a fixed action pattern display comprising discrete motor components to indicate territoriality and aggression. Displays directed to intruders contain an extra introductory component and modifying postural elements, whereas non-directed displays given in the absence of intruders lack these features and appear to be used to advertise territory ownership. Although the sequence of display components remained the same across non-directed, male-directed and female-directed displays, resident males differed in pushup duration and the number of pushups per display in relation to individual body size. This display variance might function to provide an honest signal revealing the body size or the physical condition of each individual, permitting opponents to assess each other effectively through their displays. Visual signals produced by intruding lizards were qualitatively distinct from the displays given by residents, and appear to indicate submission. However, male and female intruders differed in the frequency with which each type of submissive gesture was performed, implying that this might convey intruder sex.