bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long-Term Suppression of Hepatitis B Virus Replication by Short Hairpin RNA Expression Using the Scaffold/Matrix Attachment Region-Based Replicating Vector System pEPI-1
Authors: Jenke Andreas C. W. , Wilhelm Andreas D. , Orth Valerie , Lipps Hans Joachim , Protzer Ulrike , Wirth Stefan 
Published: May 2008

ABSTRACT
Since the emergence of viral resistance of hepatitis B virus (HBV) during treatment is becoming an important issue even with newer drugs, there is a need for alternative treatment options such as, for example, RNA interference (RNAi) technology. While short-term suppression of HBV replication is easily achieved with small interfering RNA oligonucleotides, this is not the case for long-term suppression due to the lack of an optimal vector system. Based on the nonviral scaffold/matrix attachment region (S/MAR)-based vector system pEPI-1, which is free of common side effects and is stably retained as an episome even in the absence of selection, we designed a short hairpin RNA (shRNA) expression vector called pEPI-RNAi for HBV suppression. HBV-replicating HepG2.2.15 cells were transfected with pEPI-RNAi, and the intracellular status of the plasmid was followed by PCR and Southern analysis. HBV replication was measured on the DNA, RNA, and protein level. HBV RNA expression was reduced by almost 85% 3 months posttransfection with pEPI-RNAi. At 8 months posttransfection in the absence of antibiotic selection pressure, the suppression level was still 70% and the vector was retained as an episome. The reduction of total intracellular HBV DNA at this point was 77%, showing a marked suppression of HBV DNA replication. At a comparable level, secretion of viral antigens, as well as progeny HBV virions, was inhibited. The S/MAR-based vector system pEPI-1 allows long-term suppression of HBV replication by the expression of suitable shRNAs. Due to its unique properties compared to commonly used vectors, it provides an interesting option for the treatment of chronically HBV-infected individuals.
Accumulation of
99m
Tc-Ciprofloxacin in
Staphylococcus aureus
and
Pseudomonas aeruginosa
Authors: Sierra J. M. , Rodriguez-Puig D. , Soriano A. , Mensa J. , Piera C. , Vila J. 
Published: May 2008

ABSTRACT

The use of radiopharmaceuticals for the diagnosis of infection is increasing due to their ability to distinguish between septic and aseptic inflammation. The aim of this study was to analyze the intracellular accumulation of technetium-99m-ciprofloxacin in strains of
Staphylococcus aureus
and
Pseudomonas aeruginosa
harboring an overexpression of NorA and MexAB-OprM, respectively.
Addition of Rifampin to Standard Therapy for Treatment of Native Valve Infective Endocarditis Caused byStaphylococcus aureus
Authors: Riedel David J. , Weekes Elizabeth , Forrest Graeme N. 
Published: May 2008

ABSTRACTStaphylococcus aureusis a common cause of native valve infective endocarditis (IE). Rifampin is often added to traditional therapy for the management of seriousS. aureusinfections. There are no large, prospective studies documenting the safety and efficacy of adjunctive therapy with rifampin for treatment of native valveS. aureusIE. We reviewed all cases of definite native valveS. aureusIE confirmed by modified Duke criteria in a large urban hospital between 1 January 2004 and 31 December 2005. A retrospective cohort analysis was used to assess the impact of the addition of rifampin to standard therapy. There were 42 cases ofS. aureusIE treated with the addition of rifampin and 42 controls. Cases received a median of 20 days of rifampin (range, 14 to 48 days). Rifampin-resistantS. aureusisolates developed in nine cases who received rifampin before clearance of bacteremia (56%), while significant hepatic transaminase elevations also occurred in nine cases, all of whom had hepatitis C infection. Unrecognized significant drug-drug interactions with rifampin occurred frequently (52%). Cases were more likely to have a longer duration of bacteremia (5.2 versus 2.1 days; P < 0.001) and were less likely to survive (79% versus 95%;P= 0.048) than controls. Our results suggest that the potential for hepatotoxicity, drug-drug interactions, and the emergence of resistantS. aureusisolates warrants a careful risk-benefit assessment before adding rifampin to standard antibiotic treatment of native valveS. aureusIE until further clinical studies are performed.
Resistance and Virulence of
Pseudomonas aeruginosa
Clinical Strains Overproducing the MexCD-OprJ Efflux Pump
Authors: Jeannot Katy , Elsen Sylvie , Köhler Thilo , Attree Ina , van Delden Christian , Plésiat Patrick 
Published: May 2008

ABSTRACT

Since their initial description 2 decades ago, MexCD-OprJ-overproducing efflux mutants of
Pseudomonas aeruginosa
(also called
nfxB
mutants) have rarely been described in the clinical setting. Screening of 110 nonreplicate clinical isolates showing moderate resistance to ciprofloxacin (MIC from 0.5 μg/ml to 4 μg/ml) yielded only four mutants (3.6%) of that type harboring various alterations in the repressor gene
nfxB
. MexCD-OprJ upregulation correlated with an increased resistance to ciprofloxacin, cefepime, and chloramphenicol in most of the clinical strains, concomitant with a higher susceptibility to ticarcillin, aztreonam, imipenem, and aminoglycosides. Evidence was obtained that this increased susceptibility to aminoglycosides results from the impaired activity of efflux pump MexXY-OprM. Furthermore, MexCD-OprJ upregulation was found to impair bacterial growth and to have a strain-specific, variable impact on rhamnolipid, elastase, phospholipase C, and pyocyanin production. Review of patient files indicated that the four
nfxB
mutants were responsible for confirmed cases of infection and emerged during long-term therapy with ciprofloxacin. Taken together, these data show that, while rather infrequent among
P. aeruginosa
strains with low-level resistance to ciprofloxacin, MexCD-OprJ-overproducing mutants may be isolated after single therapy with fluoroquinolones and may be pathogenic.
Human Immunodeficiency Virus Type 1 (HIV-1) Integration: a Potential Target for Microbicides To Prevent Cell-Free or Cell-Associated HIV-1 Infection
Authors: Terrazas-Aranda Katty , Van Herrewege Yven , Hazuda Daria , Lewi Paul , Costi Roberta , Di Santo Roberto , Cara Andrea , Vanham Guido 
Published: May 2008

ABSTRACT

Conceptually, blocking human immunodeficiency virus type 1 (HIV-1) integration is the last possibility for preventing irreversible cellular infection. Using cocultures of monocyte-derived dendritic cells and CD4
+
T cells, which represent primary targets in sexual transmission, we demonstrated that blocking integration with integrase strand transfer inhibitors (InSTIs), particularly L-870812, could consistently block cell-free and cell-associated HIV-1 infection. In a pretreatment setting in which the compound was present before and during infection and was afterwards gradually diluted during the culture period, the naphthyridine carboxamide L-870812 blocked infection with the cell-free and cell-associated HIV-1 Ba-L strain at concentrations of, respectively, 1,000 and 10,000 nM. The potency of L-870812 was similar to that of the nucleotide reverse transcriptase inhibitor
R
-9-(2-phosphonylmethoxypropyl) adenine (PMPA) but one or two orders of magnitude lower than those of the nonnucleoside reverse transcriptase inhibitors UC781 and TMC120. In contrast, the diketo acid RDS derivative InSTIs showed clear-cut but weaker antiviral activity than L-870812. Moreover, L-870812 completely blocked subtype C and CRFO2_AG primary isolates, which are prevalent in the African heterosexual epidemic. Furthermore, the addition of micromolar concentrations of L-870812 even 24 h after infection could still block both cell-free and cell-associated Ba-L, opening the prospect of postexposure prophylaxis. Finally, an evaluation of the combined activity of L-870812 with either T20, zidovudine, PMPA, UC781, or TMC120 against replication-deficient HIV-1 Ba-L (
env
) pseudovirus suggested synergistic activity for all combinations. Importantly, compounds selected for the study by using the coculture model were devoid of acute or delayed cytotoxic effects at HIV-blocking concentrations. Therefore, these findings provide evidence supporting consideration of HIV-1 integration as a target for microbicide development.
Presence of Wild-Type and Attenuated
Salmonella enterica
Strains in Brain Tissues following Inoculation of Mice by Different Routes
Authors: Bollen Wendy S. , Gunn Bronwyn M. , Mo Hua , Lay Margarita K. , Curtiss Roy 
Published: May 2008

ABSTRACT

Salmonella enterica
serovar Typhi and Typhimurium vaccine candidates elicit significant immune responses in mice by intranasal (i.n.) immunization. Because of the proximity of the cribriform plate of the ethmoid bone, we were concerned that
Salmonella
bacteria delivered i.n. might access the brain. Accordingly, wild-type and attenuated (by single and double mutations) strains of
S. enterica
serovars Typhimurium and Typhi were recovered at low numbers initially from the olfactory lobe and then from the brain for 3 to 4 days after i.n. immunization. This was independent of
invA
gene function. Although the presence of bacteria in blood 1 to 3 h after i.n. inoculation was sometimes observed, this was infrequent compared to the frequency of bacteria detected in brain tissues. In confirmation of recent observations by Wickham et al. (M. E. Wickham, N. F. Brown, J. Provias, B. B. Finlay, and B. K. Coombes, BMC Infect. Dis.
7:
65, 2007) that oral inoculation with wild-type
S. enterica
serovar Typhimurium strains lead to bacteria in blood with subsequent colonization of brain tissues with neurological symptoms of disease, we found similar results by using the i.n. and intraperitoneal (i.p.) routes of inoculation for wild-type but not for attenuated strains of
S. enterica
serovar Typhimurium. In contrast, a highly modified attenuated
S. enterica
serovar Typhimurium strain was not present in brain tissues when administered at higher doses by the oral, i.n., and i.p. routes than the wild-type strain even though the presence of bacteria in blood was detectable 1 to 3 h after inoculation by each of the three routes. Our results indicate that i.n. and possibly even oral delivery of live
Salmonella
vaccines may be unsafe although it is possible to reduce this risk by appropriate genetic modifications.
Common Strategies To Prevent and Modulate Experimental Cerebral Malaria in Mouse Strains with Different Susceptibilities
Authors: Randall Louise M. , Amante Fiona H. , McSweeney Karli A. , Zhou Yonghong , Stanley Amanda C. , Haque Ashraful , Jones Malcolm K. , Hill Geoff R. , Boyle Glen M. , Engwerda Christian R. 
Published: May 2008

ABSTRACTCerebral malaria (CM) is a severe complication ofPlasmodium falciparuminfection, predominantly experienced by children and nonimmune adults, which results in significant mortality and long-term sequelae. Previous studies have reported distinct susceptibility gene loci in CBA/CaH (CBA) and C57BL/6 (B6) mice with experimental CM (ECM) caused by infection withPlasmodium bergheiANKA. Here we present an analysis of genome-wide expression profiles in brain tissue taken from B6 and CBA mice with ECM and report significant heterogeneity between the two mouse strains. Upon comparison of the leukocyte composition of ECM brain tissue, microglia were expanded in B6 mice but not CBA mice. Furthermore, circulating levels of gamma interferon, interleukin-10, and interleukin-6 were significantly higher in the serum of B6 mice than in that of CBA mice with ECM. Two therapeutic strategies were applied to B6 and CBA mice, i.e., (i) depletion of regulatory T (Treg) cells prior to infection and (ii) depletion of CD8+T cells after the establishment of ECM. Despite the described differences between susceptible mouse strains, depletion of Treg cells before infection attenuated ECM in both B6 and CBA mice. In addition, the depletion of CD8+T cells when ECM symptoms are apparent leads to abrogation of ECM in B6 mice and a lack of progression of ECM in CBA mice. These results may have important implications for the development of effective treatments for human CM.
Macrophage Migration Inhibitory Factor and Interleukin-8 Produced by Gastric Epithelial Cells during
Helicobacter pylori
Exposure Induce Expression and Activation of the Epidermal Growth Factor Receptor
Authors: Beswick Ellen J. , Reyes Victor E. 
Published: May 2008

ABSTRACT

While a link between
Helicobacter pylori
exposure and gastric cancer has been established, the underlying mechanisms remain unclear.
H. pylori
induces a chronic inflammatory response in infected individuals. A link between chronic inflammation and carcinogenesis has long been suggested but never elucidated. Epidermal growth factor receptor (EGFR) signaling plays an important role in both proinflammatory and procarcinogenic mechanisms and is upregulated on gastric epithelial cells (GECs) during
H. pylori
exposure. The aim of this study was to examine the effects of two important proinflammatory cytokines released during
H. pylori
infection, macrophage migration inhibitory factor (MIF) and interleukin-8 (IL-8), on the expression and transactivation of EGFR and on the proliferation of GECs during
H. pylori
exposure. The expression of EGFR by GECs was increased by exposure to either
H. pylori
, recombinant MIF, or recombinant IL-8. However,
cag
pathogenicity island knockout strains of
H. pylori
had very little effect on expression. MIF and IL-8 also induced phosphorylation of EGFR, signaling events, and proliferation during
H. pylori
exposure, all of which were decreased when they were neutralized by these cytokines or were blocked from their receptors. The overall role of EGFR in these responses to
H. pylori
exposure was assessed by knocking down EGFR expression by small interfering RNA.
Role of membrane cholesterol in platelet calcium signalling in response to VWF and collagen under stasis and flow
Authors: van Lier Marjolijn , Verhoef Sandra , Cauwenberghs Sandra , Heemskerk Johan , Akkerman Jan-Willem , Heijnen Harry 
Published: May 2008

SummarySeveral studies have highlighted a specific role for membrane cholesterol domains in platelet signalling. Upon adhesion to von Willebrand factor (VWF) or collagen, cholesterol-rich domains (CRDs) accumulate in filopodial extensions and selectively harbour counterpart receptors (GPIb and GPVI) and associated signalling molecules. In the present study we have addressed the role of membrane cholesterol in Ca2+ signalling and secretion during the interaction of platelets with VWF and collagen.VWF/ ristocetin-induced platelet aggregation was delayed after treatment with methyl β-cyclodextrin (mbCD), but the maximal aggregation response was not affected. Platelet spreading but not adhesion to immobilised VWF under flow was attenuated by cholesterol removal, and accompanied by moderate lowering in the spiking Ca2+ response. On the other hand, platelet interaction with collagen was quite sensitive to cholesterol depletion. Platelet aggregation decreased after treatment with mbCD, and Ca2+ responses were decreased, both under static and flow conditions. Cholesterol depletion affected the secondary feedback activation via release of thromboxane A2 and ADP. The collagen-induced secretion of alpha granules and surface translocation of P-selectin and CD63 was also critically affected by cholesterol depletion. Confocal microscopy showed localization of p-Tyr at sites of contact with substrate and other platelets, where also CRDs accumulate. Our data thus reveal a more critical role for membrane cholesterol in collagen-induced than in VWF-induced Ca2+ signalling, and furthermore support the concept that secondary activation responses are dependent on intact CRDs.
Accuracy of the CoaguChek XS for point-of-care international normalized ratio (INR) measurement in children requiring warfarin
Authors: Black Karina , Massicotte Mary , Bauman Michelle , Kuhle Stefan , Howlett-Clyne Susan , Cembrowski George , Bajzar Laszlo , Bauman Mary 
Published: May 2008

SummaryPoint-of-care INR (POC INR) meters can provide a safe and effective method for monitoring oral vitamin K antagonists (VKAs) in children. Stollery Children’s Hospital has a large POC INR meter loan program for children requiring oral VKAs. Our protocol requires that POC INR results be compared to the standard laboratory INR for each child on several consecutive tests to ensure accuracy of CoaguChek XS® (Roche Diagnostics, Basel Switzerland) meter. It was the objective of the study to determine the accuracy of the CoaguChek XS by comparing whole blood INR results from the CoaguChek XS to plasma INR results from the standard laboratory in children. POC INR meter validations were performed on plasma samples from two time points from 62 children receiving warfarin by drawing a venous blood sample for laboratory prothrombin (PT)-INR measurements and simultaneous INR determinations using the POC-INR meter. Agreement between CoaguChek XS INR and laboratory INR was assessed using Bland-Altman plots. Bland-Altman's 95% limits of agreement were 0.11 (-0.20; 0.42) and 0.13 (-0.22; 0.48) at the two time points, respectively. In conclusion, the CoaguChek XS meter appraisal generates an accurate and precise INR measure in children when compared to laboratory INR test results.
Fluid loss does not explain coagulation activation during air travel
Authors: Schreijer Anja , Cannegieter Suzanne , Caramella Marianna , Meijers Joost , Krediet Raymond , Simons Ries , Rosendaal Frits 
Published: May 2008

SummaryThe mechanism of air travel-related venous thrombosis is unclear. Although immobility plays a pivotal role, other factors such as fluid loss may contribute. We investigated whether fluid loss occurred more in individuals with coagulation activation after air travel than in subjects without. As a secondary aim, we investigated whether fluid loss per se occurred during air travel. In this crossover study, 71 healthy volunteers were exposed to eight hours of air travel, eight hours immobilization in a cinema, and a daily-life control situation. Markers of fluid loss (haematocrit, serum osmolality and albumin) and of coagulation activation were measured before and after each exposure. The study included ll volunteers with and 55 volunteers without coagulation activation during the flight. The change in parameters of fluid loss was not different in volunteers with an activated clotting system from those without (difference between groups in haematocrit: −0.6%, 95% confidence interval [CI]: −1.9 to 0.6). On a group level, mean haematocrit values decreased during all three exposures. However, in some individuals it increased, which occurred in more participants during the flight (34%; 95% CI 22 to 46) than during the daily-life situation (l9%; 95% CI 10 to 28). These findings do not support the hypothesis that fluid loss contributes to thrombus formation during air travel.
Metabolic syndrome, haemostasis and thrombosis
Authors: Juhan-Vague Irène , Alessi Marie-Christine 
Published: May 2008

SummaryThe metabolic syndrome (metS), a concurrence of abdominal fat, disturbed glucose and insulin metabolism, dyslipidemia, and hypertension has been strongly associated not only with subsequent development of type 2 diabetes but also with athero-thrombosis. The physiopathology of this association is complex. The metS affects the thrombogenicity of circulating blood. Apart from its effect on platelets, a procoagulant and hypofibrinolytic state has been identified; mainly the result of the inflammatory state, dyslipidemia, and liver fat accumulation that accompany the MetS. Among haemostasis disturbances, the strong rise in the inhibitor of plasminogen activator type 1 plasma level is the most documented abnormality implicating the participation of the oxidative stress and inflammatory state developed during the metS. Endothelial dysfunction is also a central feature. Moreover, secretion products of fat tissues (adipokines) are now thought to have direct modulating effects on the vascular and the circulating cells. In support of these data, the metS, may predispose not only to atherosclerosis but also to venous thrombosis.
Cost and outcome: Comparisons of two alternative bypassing agents for persons with haemophilia A complicated by an inhibitor
Authors: Astermark Jan , Donfield Sharyne , Berntorp Erik , Carlsson Katarina 
Published: May 2008

SummaryThe development of inhibitory antibodies to factor VIII is a serious complication of haemophilia. Two haemostatic agents with different bypassing mechanisms have been used in the treatment of patients with inhibitors: activated prothrombin complex concentrate (aPCC) and recombinant factor VIIa (rFVIIa). The objective was to compare cost and outcome of aPCC and rFVIIa in the treatment of joint bleeds. The analyses were based on the FENOC (FEIBA NovoSeven Comparative Study) crossover study where 48 patients used aPCC and rFVIIa to treat two joint bleeds. Incremental cost-effectiveness ratios were calculated for three outcome measures and the variation in cost was analyzed using two alternative regression methods. Results were subjected to sensitivity analyses. Key determinants of cost were prescribed dose, bodyweight and treatment in addition to protocol.The cost of aPCC was on average lower than rFVIIa. At all but one time point, patients rated slightly higher (but not statistically significantly) percentages of treatment efficacy and stopping of the bleed by aPCC. The reported reduction in pain from start of treatment up to 48 hours varied considerably among individuals. The different relative prices in the US, Turkey and Sweden mattered, but did not reverse the main results. In conclusion, the cost per episode was significantly lower for aPCC. The large individual-level variation in reduction of pain supports decisions that consider the individual patient’s experience and that accept trade-offs between cost and reduction in pain rather than focusing on cost only.
Pathophysiological considerations to thrombophilia in the treatment of multiple myeloma with thalidomide and derivates
Authors: Gieseler Frank 
Published: May 2008

SummaryLenalidomide, a derivate of thalidomide, has recently been approved in Europe for the treatment of patients with multiple myeloma. Although the substance has a better effect/side-effect profile, especially with regard to teratogenicity and neurotoxicity, the rate of therapy-induced thrombosis seems comparable to thalidomide. The observed thromboembolic events were accompanied with a high rate of deleterious pulmonary embolism. Interestingly, the substances alone are not thrombogenic but combination with anthracyclines, dexamethasone or erythropesis-stimulating factors increases the risk considerably. As up to one third of patients treated with such combinations are affected, antithrombotic co-medication is highly recommended. This review elucidates the complex interactions between an activated coagulation-system in myeloma patients and the molecular effects of these drugs. This perception is important to choose the proper prophylactic co-medication without increasing the risk of bleeding, especially in first-line treatment, patients with high paraprotein-levels, or thrombopenia, either therapy-induced or due to bone-marrow infiltration.