bluuebunny/crossref_metadata_2025 huggingface dataset:
Hereditary hemochromatosis is reflected in the iron isotope composition of blood
Authors: Krayenbuehl Pierre-Alexandre , Walczyk Thomas , Schoenberg Ronny , von Blanckenburg Friedhelm , Schulthess Georg
Published: January 2005

It has recently been shown that the iron isotopic composition of blood differs between individuals and sexes, which is supposed to reflect individual differences in iron metabolism. We hypothesized that patients suffering from hereditary hemochromatosis would demonstrate alterations in the iron isotopic composition of blood due to persistent up-regulation of intestinal iron absorption. Blood from 30 patients with homozygous C282Y hemochromatosis was analyzed for iron isotopic composition by a newly developed technique using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Blood of patients with hemochromatosis is characterized by a higher 56Fe/54Fe isotope ratio than blood of healthy individuals, which are either members of an age-matched control group (n = 10; P < .001) or young adults (n = 36; P < .001). In patients with hereditary hemochromatosis, the 56Fe/54Fe isotope ratio of blood significantly correlates with total-body iron accumulation, severity of clinical disease, and the need for regular phlebotomies to prevent iron reaccumulation. We conclude that blood of patients with hereditary hemochromatosis contains more of the heavier iron isotopes than blood of healthy individuals. The primary determinant of the iron isotopic composition of blood appears to be isotope-sensitive iron absorption in the intestine and the efficiency of this process.
P2Y1 and P2Y12 receptors for ADP desensitize by distinct kinase-dependent mechanisms
Authors: Hardy Adam R. , Conley Pamela B. , Luo Jiansong , Benovic Jeffrey L. , Poole Alastair W. , Mundell Stuart J.
Published: January 2005

Adenosine 5′-diphosphate (ADP) plays a central role in regulating platelet function by the activation of the G protein–coupled receptors P2Y1 and P2Y12. Although it is well established that aggregation responses of platelets to ADP desensitize, the underlying mechanisms involved remain unclear. In this study we demonstrate that P2Y1- and P2Y12-mediated platelet responses desensitize rapidly. Furthermore, we have established that these receptors desensitize by different kinase-dependent mechanisms. G protein–coupled receptor kinase (GRK) 2 and GRK6 are both endogenously expressed in platelets. Transient overexpression of dominant-negative mutants of these kinases or reductions in endogenous GRK expression by the use of specific siRNAs in 1321N1 cells showed that P2Y12, but not P2Y1, desensitization is mediated by GRKs. In contrast, desensitization of P2Y1, but not P2Y12, is largely dependent on protein kinase C activity. This study is the first to show that both P2Y1 and P2Y12 desensitize in human platelets, and it reveals ways in which their sensitivity to ADP may be differentially and independently altered.
Synergistic interactions between imatinib mesylate and the novel phosphoinositide-dependent kinase-1 inhibitor OSU-03012 in overcoming imatinib mesylate resistance
Authors: Tseng Ping-Hui , Lin Ho-Pi , Zhu Jiuxiang , Chen Kuen-Feng , Hade Erinn M. , Young Donn C. , Byrd John C. , Grever Michael , Johnson Kara , Druker Brian J. , Chen Ching-Shih
Published: January 2005

Resistance to the Ableson protein tyrosine (Abl) kinase inhibitor imatinib mesylate has become a critical issue for patients in advanced phases of chronic myelogenous leukemia. Imatinib-resistant tumor cells develop, in part, as a result of point mutations within the Abl kinase domain. As protein kinase B (Akt) plays a pivotal role in Abl oncogene-mediated cell survival, we hypothesize that concurrent inhibition of Akt will sensitize resistant cells to the residual apoptotic activity of imatinib mesylate, thereby overcoming the resistance. Here, we examined the effect of OSU-03012, a celecoxib-derived phosphoinositide-dependent kinase-1 (PDK-1) inhibitor, on imatinib mesylate-induced apoptosis in 2 clinically relevant breakpoint cluster region (Bcr)-Abl mutant cell lines, Ba/F3p210E255K and Ba/F3p210T315I. The 50% inhibitory concentration (IC50) values of imatinib mesylate to inhibit the proliferation of Ba/F3p210E255K and Ba/F3p210T315I were 14 ± 4 and 30 ± 2 μM, respectively. There was no cross-resistance to OSU-03012 in these mutant cells with an IC50 of 5 μM irrespective of mutations. Nevertheless, in the presence of OSU-03012 the susceptibility of these mutant cells to imatinib-induced apoptosis was significantly enhanced. This synergistic action was, at least in part, mediated through the concerted effect on phospho-Akt. Together these data provide a novel therapeutic strategy to overcome imatinib mesylate resistance, especially with the Abl mutant T315I.
Platelet homeostasis is regulated by platelet expression of CD47 under normal conditions and in passive immune thrombocytopenia
Authors: Olsson Mattias , Bruhns Pierre , Frazier William A. , Ravetch Jeffrey V. , Oldenborg Per-Arne
Published: January 2005

Interaction between target cell CD47 and the inhibitory macrophage receptor signal regulatory protein α (SIRPα) counteracts macrophage phagocytosis of CD47-expressing host cells. As platelets also express CD47, we asked whether inhibitory CD47/SIRPα signaling regulates normal platelet turnover and clearance of platelets in immune thrombocytopenic purpura (ITP). CD47-/- mice had a mild spontaneous thrombocytopenia, which was not due to a decreased platelet half-life as a result of increased expression of P-selectin, CD61, or phosphatidylserine. In contrast, CD47-/- platelets were rapidly cleared when transfused into CD47+/+ recipients, whereas CD47+/- platelets had a nearly normal half-life in CD47+/+ mice under nonautoimmune conditions. CD47-/- mice were more sensitive to ITP, as compared with CD47+/+ mice. In vitro, macrophage phagocytosis of immunoglobulin G (IgG)–opsonized CD47-/- platelets was significantly higher than that for equally opsonized CD47+/+ platelets. However, when SIRPα was blocked, phagocytosis of CD47+/+ platelets increased to the level of CD47-/- platelets. Phagocytosis of opsonized CD47+/- platelets was higher than that for CD47+/+ platelets, but lower than that for CD47-/- platelets, suggesting a gene-dose effect of CD47 in this system. In conclusion, we suggest that inhibitory CD47/SIRPα signaling is involved in regulating platelet phagocytosis in ITP, and that targeting SIRPα may be a new means of reducing platelet clearance in ITP.
Anomalous megakaryocytopoiesis in mice with mutations in the c-Myb gene
Authors: Metcalf Donald , Carpinelli Marina R. , Hyland Craig , Mifsud Sandra , DiRago Ladina , Nicola Nicos A. , Hilton Douglas J. , Alexander Warren S.
Published: January 2005

Mpl -/- mice bearing the Plt3 or Plt4 mutations in the c-Myb gene exhibit thrombopoietin (TPO)–independent supraphysiological platelet production accompanied by excessive megakaryocytopoiesis and defective erythroid and lymphoid cell production. To better define the cellular basis for the thrombocytosis in these mice, we analyzed the production and characteristics of megakaryocytes and their progenitors. Consistent with thrombocytosis arising from hyperactive production, the high platelet counts in mice carrying the c-MybPlt4 allele were not accompanied by any significant alteration in platelet half-life. Megakaryocytes in c-Myb mutant mice displayed reduced modal DNA ploidy and, among the excessive numbers of megakaryocyte progenitor cells, more mature precursors were particularly evident. Megakaryocyte progenitor cells carrying the Plt3 or Plt4 c-Myb mutations, but not granulocyte-macrophage progenitors, exhibited 200-fold enhanced responsiveness to granulocyte-macrophage colony-stimulating factor (GM-CSF), suggesting that altered responses to cytokines may contribute to expanded megakaryocytopoiesis. Mutant preprogenitor (blast colony-forming) cells appeared to have little capacity to form megakaryocyte progenitor cells. In contrast, the spleens of irradiated mice 12 days after transplantation with mutant bone marrow contained abundant megakaryocyte progenitor cells, suggesting that altered c-Myb activity skews differentiation commitment in spleen colony-forming units (CFU-S) in favor of excess megakaryocytopoiesis.
Large scale hierarchical clustering of protein sequences
Authors: Krause Antje , Stoye Jens , Vingron Martin
Published: January 2005

Background

Searching a biological sequence database with a query sequence looking for homologues has become a routine operation in computational biology. In spite of the high degree of sophistication of currently available search routines it is still virtually impossible to identify quickly and clearly a group of sequences that a given query sequence belongs to.

Results

We report on our developments in grouping all known protein sequences hierarchically into superfamily and family clusters. Our graph-based algorithms take into account the topology of the sequence space induced by the data itself to construct a biologically meaningful partitioning. We have applied our clustering procedures to a non-redundant set of about 1,000,000 sequences resulting in a hierarchical clustering which is being made available for querying and browsing at http://systers.molgen.mpg.de/.

Conclusions

Comparisons with other widely used clustering methods on various data sets show the abilities and strengths of our clustering methods in producing a biologically meaningful grouping of protein sequences.
Extracellular degradation of lipoprotein lipase in rat adipose tissue
Authors: Wu Gengshu , Olivecrona Gunilla , Olivecrona Thomas
Published: January 2005

Background

Recent studies in vivo indicate that short-term regulation of lipoprotein lipase (LPL) in rat adipose tissue is post-translational and occurs by a shift of the lipase protein towards an inactive form under the influence of another gene with short-lived message and product. It has not been possible to reproduce this process with isolated adipocytes suggesting that other cells are needed, and perhaps mediate the regulation. The objective of the present study was, therefore, to explore if explants of adipose tissue could be used for studies of the regulatory process.

Results

When explants of rat epididymal adipose tissue were incubated, LPL mass and activity decreased rapidly. Mass and activity within adipocytes remained constant for at least six hours, demonstrating that it was the extracellular portion of the enzyme that decreased. Adipocytes isolated from the explants after three or six hours of incubation retained their ability to secrete LPL to the medium. Addition of a cocktail of protease inhibitors to the incubation medium slowed down the decrease of LPL mass. Chloroquine was without effect, indicating that the degradation was not lysosomal. 125I-labeled LPL added to the medium was degraded to acid soluble products, indicating that the degradation occurred extracellularly. Fragmentation of the labelled lipase occurred in conditioned medium and this process was virtually abolished by two MMP inhibitors.

Conclusions

The decrease of LPL mass and activity that occurs when explants of rat adipose tissue are incubated is due to proteolysis of extracellular LPL. The adipocytes continue to produce and secrete the enzyme. The effect of inhibitors indicates, but does not prove, that the degradation is mediated by MMPs. It appears that this process is accelerated in the tissue fragments compared to intact tissue.
Genetics and geometry of canalization and developmental stability in Drosophila subobscura
Authors: Santos Mauro , Iriarte Pedro Fernández , Céspedes Walkiria
Published: January 2005

Background

Many properties of organisms show great robustness against genetic and environmental perturbations. The terms canalization and developmental stability were originally proposed to describe the ability of an organism to resist perturbations and to produce a predictable target phenotype regardless of random developmental noise. However, the extent to which canalization and developmental stability are controlled by the same set of genes and share underlying regulatory mechanisms is largely unresolved.

Results

We have analyzed the effects of clinal genetic variation (inversion polymorphism) on wing asymmetry by applying the methods of geometric morphometrics in the context of quantitative genetics using isochromosomal lines of Drosophila subobscura. For the analysis of overall size, developmental stability was positively correlated with levels of heterozygosity and development at the optimal temperature. For analyses of shape, the overall comparisons by matrix correlations indicate that inter- and intraindividual variation levels were poorly correlated, a result also supported when comparing the vectors describing patterns of variation of landmark position. The lack of similarity was basically due to the discrepancy between the genetic and environmental components of the interindividual variation. Finally, the analyses have also underscored the presence of genetic variation for directional asymmetry.

Conclusions

The results strongly support the hypothesis that environmental canalization and developmental stability share underlying regulatory mechanisms, but environmental and genetic canalization are not functionally the same. A likely explanation for this lack of association is that natural wing shape variation in Drosophila populations is loosely related to individual fitness.
Genetical and functional investigation of fliC genes encoding flagellar serotype H4 in wildtype strains of Escherichia coli and in a laboratory E. coli K-12 strain expressing flagellar antigen type H48
Authors: Beutin Lothar , Strauch Eckhard , Zimmermann Sonja , Kaulfuss Stefan , Schaudinn Christoph , Männel Andrea , Gelderblom Hans R
Published: January 2005

Background

Serotyping of O-(lipopolysaccharide) and H-(flagellar) antigens is a wideley used method for identification of pathogenic strains and clones of Escherichia coli. At present, 176 O- and 53 H-antigens are described for E. coli which occur in different combinations in the strains. The flagellar antigen H4 is widely present in E. coli strains of different O-serotypes and pathotypes and we have investigated the genetic relationship between H4 encoding fliC genes by PCR, nucleotide sequencing and expression studies.

Results

The complete nucleotide sequence of fliC genes present in E. coli reference strains U9-41 (O2:K1:H4) and P12b (O15:H17) was determined and both were found 99.3% (1043 of 1050 nucleotides) identical in their coding sequence. A PCR/RFLP protocol was developed for typing of fliC-H4 strains and 88 E. coli strains reacting with H4 antiserum were investigated. Nucleotide sequencing of complete fliC genes of six E. coli strains which were selected based on serum agglutination titers, fliC-PCR genotyping and reference data revealed 96.6 to 100% identity on the amino acid level. The functional expression of flagellin encoded by fliC-H4 from strain U9-41 and from our strain P12b which is an H4 expressing variant type was investigated in the E. coli K-12 strain JM109 which encodes flagellar type H48. The fliC recombinant plasmid carrying JM109 strains reacted with both H4 and H48 specific antisera whereas JM109 reacted only with the H48 antiserum. By immunoelectron microscopy, we could show that the flagella made by the fliC-H4 recombinant plasmid carrying strain are constituted of H48 and H4 flagellins which are co-assembled into functional flagella.

Conclusion

The flagellar serotype H4 is encoded by closely related fliC genes present in serologically different types of E. coli strainswhich were isolated at different time periods and geographical locations. Our expression studies show for the first time, that flagellins of different molecular weigth are functionally expressed and coassembled in the same flagellar filament in E. coli.
Iron homeostasis in neuronal cells: a role for IREG1
Authors: Aguirre Pabla , Mena Natalia , Tapia Victoria , Arredondo Miguel , Núñez Marco T
Published: January 2005

Background

Iron is necessary for neuronal function but in excess generates neurodegeneration. Although most of the components of the iron homeostasis machinery have been described in neurons, little is known about the particulars of their iron homeostasis. In this work we characterized the response of SH-SY5Y neuroblastoma cells and hippocampal neurons to a model of progressive iron accumulation.

Results

We found that iron accumulation killed a large proportion of cells, but a sub-population became resistant to iron. The surviving cells evoked an adaptative response consisting of increased synthesis of the iron-storage protein ferritin and the iron export transporter IREG1, and decreased synthesis of the iron import transporter DMT1. Increased expression of IREG1 was further substantiated by immunocytochemistry and iron efflux experiments. IREG1 expression directly correlated with iron content in SH-SY5Y and hippocampal cells. Similarly, a high correlation was found between IREG1 expression and the rate of iron efflux from SH-SY5Y cells.

Conclusions

Neuronal survival of iron accumulation associates with increased expression of the efflux transporter IREG1. Thus, the capacity of neurons to express IREG1 may be one of the clues to iron accumulation survival.
Treatment of trigeminal ganglion neurons in vitro with NGF, GDNF or BDNF: effects on neuronal survival, neurochemical properties and TRPV1-mediated neuropeptide secretion
Authors: Price Theodore J , Louria Michael D , Candelario-Soto Damaries , Dussor Gregory O , Jeske Nathanial A , Patwardhan Amol M , Diogenes Anibal , Trott Amanda A , Hargreaves Kenneth M , Flores Christopher M
Published: January 2005

Background

Nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) all play important roles in the development of the peripheral sensory nervous system. Additionally, these growth factors are proposed to modulate the properties of the sensory system in the adult under pathological conditions brought about by nerve injury or inflammation. We have examined the effects of NGF, GDNF and BDNF on adult rat trigeminal ganglion (TG) neurons in culture to gain a better understanding of how these growth factors alter the cytochemical and functional phenotype of these neurons, with special attention to properties associated with nociception.

Results

Compared with no growth factor controls, GDNF, at 1 and 100 ng/ml, significantly increased by nearly 100% the number of neurons in culture at 5 days post-plating. A significant, positive, linear trend of increasing neuron number as a function of BDNF concentration was observed, also peaking at nearly 100%. NGF treatment was without effect. Chronic treatment with NGF and GDNF significantly and concentration-dependently increased 100 nM capsaicin (CAP)-evoked calcitonin gene-related peptide (CGRP) release, reaching approximately 300% at the highest concentration tested (100 ng/ml). Also, NGF and GDNF each augmented anandamide (AEA)- and arachidonyl-2-chloroethylamide (ACEA)-evoked CGRP release, while BDNF was without effect. Utilizing immunohistochemistry to account for the proportions of TRPV1- or CGRP-positive neurons under each growth factor treatment condition and then standardizing evoked CGRP release to these proportions, we observed that NGF was much more effective in enhancing CAP- and 50 mM K+-evoked CGRP release than was GDNF. Furthermore, NGF and GDNF each altered the concentration-response function for CAP- and AEA-evoked CGRP release, increasing the Emax without altering the EC50 for either compound.

Conclusions

Taken together, our results illustrate that NGF, GDNF and BDNF differentially alter TG sensory neuron survival, neurochemical properties and TRPV1-mediated neuropeptide release in culture. In particular, our findings suggest that GDNF and NGF differentially modulate TRPV1-mediated neuropeptide secretion sensitivity, with NGF having a much greater effect on a per neuron basis than GDNF. These findings are discussed in relation to possible therapeutic roles for growth factors or their modulators in pathological pain states, especially as these relate to the trigeminal system.
Pretreatment with ACE inhibitors improves acute outcome of electrical cardioversion in patients with persistent atrial fibrillation
Authors: Van Noord Trudeke , Crijns Harry JGM , van den Berg Maarten P , Van Veldhuisen Dirk J , Van Gelder Isabelle C
Published: January 2005

Background

Persistent atrial fibrillation (AF) is difficult to treat. In the absence of class I or III antiarrhythmic drugs sinus rhythm is maintained in only 30% of patients during the first year after electrical cardioversion (ECV). One of the remodeling processes induced by AF is fibrosis, which relates to inducibility and maintenance of AF. The renin-angiotensin system may play a important role in this. The aim of this study was to investigate the role of angiotensin-converting enzyme (ACE) inhibitor use on efficacy of ECV, and occurrence of subacute recurrences.

Methods

One hundred-seven consecutive patients with persistent AF underwent ECV. In twenty-eight (26%) patients ACE inhibitors had been started before initiation of the present episode of AF ('pre-treated' patients).

Results

ECV was successful in 96% of patients who were on ACE inhibitors before start of the present episode of AF compared to 80% of the patients not pre-treated (p = 0.04). After 1 month of follow-up 49% of the pre-treated patients and 50% of those not pre-treated with ACE inhibition were still in sinus rhythm (p=ns). Multivariate analysis showed that pre-treatment with ACE inhibitors and a smaller left atrial size were independent predictors of successful ECV (OR = 5.8, C.I. 1.3–26.1, and OR = 5.6, C.I. 1.2–25.3, respectively).

Conclusions

Pre-treatment with ACE inhibitors may improve acute success of ECV but does not prevend AF recurrences.
Comparison of nested case-control and survival analysis methodologies for analysis of time-dependent exposure
Authors: Essebag Vidal , Platt Robert W , Abrahamowicz Michal , Pilote Louise
Published: January 2005

Background

Epidemiological studies of exposures that vary with time require an additional level of methodological complexity to account for the time-dependence of exposure. This study compares a nested case-control approach for the study of time-dependent exposure with cohort analysis using Cox regression including time-dependent covariates.

Methods

A cohort of 1340 subjects with four fixed and seven time-dependent covariates was used for this study. Nested case-control analyses were repeated 100 times for each of 4, 8, 16, 32, and 64 controls per case, and point estimates were compared to those obtained using Cox regression on the full cohort. Computational efficiencies were evaluated by comparing central processing unit times required for analysis of the cohort at sizes 1, 2, 4, 8, 16, and 32 times its initial size.

Results

Nested case-control analyses yielded results that were similar to results of Cox regression on the full cohort. Cox regression was found to be 125 times slower than the nested case-control approach (using four controls per case).

Conclusions

The nested case-control approach is a useful alternative for cohort analysis when studying time-dependent exposures. Its superior computational efficiency may be particularly useful when studying rare outcomes in databases, where the ability to analyze larger sample sizes can improve the power of the study.
Viability testing of material derived from Mycobacterium tuberculosisprior to removal from a Containment Level-III Laboratory as part of a Laboratory Risk Assessment Program
Authors: Blackwood Kym S , Burdz Tamara V , Turenne Christine Y , Sharma Meenu K , Kabani Amin M , Wolfe Joyce N
Published: January 2005

Background

In the field of clinical mycobacteriology, Mycobacterium tuberculosis (MTB) can be a difficult organism to manipulate due to the restrictive environment of a containment level 3 (CL3) laboratory. Tests for rapid diagnostic work involving smears and molecular methods do not require CL3 practices after the organism has been rendered non-viable. While it has been assumed that after organism deactivation these techniques can be performed outside of a CL3, no conclusive study has consistently confirmed that the organisms are noninfectious after the theoretical 'deactivation' steps. Previous studies have shown that initial steps (such as heating /chemical fixation) may not consistently kill MTB organisms.

Methods

An inclusive viability study (n = 226) was undertaken to determine at which point handling of culture extraction materials does not necessitate a CL3 environment. Four different laboratory protocols tested for viability included: standard DNA extractions for IS6110 fingerprinting, crude DNA preparations for PCR by boiling and mechanical lysis, protein extractions, and smear preparations. For each protocol, laboratory staff planted a proportion of the resulting material to Bactec 12B medium that was observed for growth for 8 weeks.

Results

Of the 208 isolates initially tested, 21 samples grew within the 8-week period. Sixteen (7.7%) of these yielded positive results for MTB that included samples of: deactivated culture resuspensions exposed to 80°C for 20 minutes, smear preparations and protein extractions. Test procedures were consequently modified and tested again (n = 18), resulting in 0% viability.

Conclusions

This study demonstrates that it cannot be assumed that conventional practices (i.e. smear preparation) or extraction techniques render the organism non-viable. All methodologies, new and existing, should be examined by individual laboratories to validate the safe removal of material derived from MTB to the outside of a CL3 laboratory. This process is vital to establish in house biosafety-validated practices with the aim of protecting laboratory workers conducting these procedures.
Quetiapine augmentation of SRIs in treatment refractory obsessive-compulsive disorder: a double-blind, randomised, placebo-controlled study [ISRCTN83050762]
Authors: Carey Paul D , Vythilingum Bavanisha , Seedat Soraya , Muller Jacqueline E , van Ameringen Michael , Stein Dan J
Published: January 2005

Background

Although serotonin reuptake inhibitors are effective in the treatment of OCD, many patients fail to respond to these agents. Growing evidence from open-label and placebo-controlled trials suggests a role for augmentation of SRIs with atypical antipsychotics in OCD. Quetiapine is generally well tolerated and previous open-label data has produced mixed results in OCD and additional controlled data is needed.

Methods

We undertook a double-blind, randomised, parallel-group, flexible-dose, placebo-controlled study of quetiapine augmentation in subjects who had responded inadequately to open-label treatment with an SRI for 12 weeks. Following informed consent and screening, forty-two subjects were randomised to either placebo or quetiapine for six weeks.

Results

There was significant improvement from baseline to endpoint on the Yale-Brown Obsessive-Compulsive Scale in both the quetiapine and placebo groups (quetiapine, n = 20, p < 0.0001; placebo, n = 21, p = 0.001) with 40% (n = 8) of quetiapine and 47.6% (n = 10) of placebo treated subjects being classified as responders. Quetiapine did not demonstrate a significant benefit over placebo at the end of the six-week treatment period (p = .636). Similarly quetiapine failed to separate from placebo in the subgroup of subjects (n = 10) with co-morbid tics. Quetiapine was generally well tolerated.

Conclusions

In this study, quetiapine augmentation was no more effective than placebo augmentation of SRIs. A number of limitations in study design make comparisons with previous studies in this area difficult and probably contributed to our negative findings. Future work in this important clinical area should address these limitations.
Effect of bradykinin on nitric oxide production, urea synthesis and viability of rat hepatocyte cultures
Authors: Sesti Settimio , Martino Guglielmo , Mazzulla Sergio , Chimenti Rosa
Published: January 2005

Background

It is well known that cytotoxic factors, such as lipopolysaccharides, derange nitrogen metabolism in hepatocytes and nitric oxide (NO) is involved among the other factors regulating this metabolic pathway. Hepatocytes have been shown to express large levels of NO following exposure to endotoxins, such as bacterial lipopolysaccharide and/or cytokines, such as tumour necrosis factor-α (TNFα), interleukin-1. The control role of arginine in both urea and NO biosynthesis is well known, when NO is synthesized from arginine, by the NOS reaction, citrulline is produced. Thus, the urea cycle is bypassed by the NOS reaction. Many authors demonstrated in other cellular types, like cardiomyocytes, that bradykinin caused the increase in reactive oxygen species (ROS) generation. The simultaneous increase of NO and ROS levels could cause peroxynitrite synthesis, inducing damage and reducing cell viability. The aim of this research is to study the effect of bradykinin, a proinflammatory mediator, on cell viability and on urea production in cultures of rat hepatocytes.

Results

Hepatocytes were treated with bradykinin, that stimulates nitric oxide synthase (NOS). NO release was determined using 4,5 diaminofluorescein diacetate (DAF-2DA), as fluorescent indicator of NO. Addition of the NOS inhibitor, Ng-nitro-L-arginine methyl ester (L-NAME), to the culture medium inhibited the increase of NO production. Exposure of hepatocytes to bradykinin 0,1 mM for 2 hours resulted in a significant decrease of urea synthesis. Cell viability, instead, showed a significant decrease 24 hours after the end of bradykinin treatment as determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5diphenyl-2H-tetrazolium (MTT) assay. L-NAME addition recovered urea production and cell viability at control values.

Conclusion

The findings suggest that the cell toxicity, after bradykinin treatment, effectively depends upon exposure to increased NO levels and the effects are prevented by L-NAME. The results show also that the increased NO synthesis induces a reduced urea production, that is another index of cell damage.
A homology model of restriction endonuclease SfiI in complex with DNA
Authors: Chmiel Agnieszka A , Bujnicki Janusz M , Skowronek Krzysztof J
Published: January 2005

Background

Restriction enzymes (REases) are commercial reagents commonly used in recombinant DNA technologies. They are attractive models for studying protein-DNA interactions and valuable targets for protein engineering. They are, however, extremely divergent: the amino acid sequence of a typical REase usually shows no detectable similarities to any other proteins, with rare exceptions of other REases that recognize identical or very similar sequences. From structural analyses and bioinformatics studies it has been learned that some REases belong to at least four unrelated and structurally distinct superfamilies of nucleases, PD-DxK, PLD, HNH, and GIY-YIG. Hence, they are extremely hard targets for structure prediction and homology-based inference of sequence-function relationships and the great majority of REases remain structurally and evolutionarily unclassified.

Results

SfiI is a REase which recognizes the interrupted palindromic sequence 5'GGCCNNNN^NGGCC3' and generates 3 nt long 3' overhangs upon cleavage. SfiI is an archetypal Type IIF enzyme, which functions as a tetramer and cleaves two copies of the recognition site in a concerted manner. Its sequence shows no similarity to other proteins and nothing is known about the localization of its active site or residues important for oligomerization. Using the threading approach for protein fold-recognition, we identified a remote relationship between SfiI and BglI, a dimeric Type IIP restriction enzyme from the PD-DxK superfamily of nucleases, which recognizes the 5'GCCNNNN^NGGC3' sequence and whose structure in complex with the substrate DNA is available. We constructed a homology model of SfiI in complex with its target sequence and used it to predict residues important for dimerization, tetramerization, DNA binding and catalysis.

Conclusions

The bioinformatics analysis suggest that SfiI, a Type IIF enzyme, is more closely related to BglI, an "orthodox" Type IIP restriction enzyme, than to any other REase, including other Type IIF REases with known structures, such as NgoMIV. NgoMIV and BglI belong to two different, very remotely related branches of the PD-DxK superfamily: the α-class (EcoRI-like), and the β-class (EcoRV-like), respectively. Thus, our analysis provides evidence that the ability to tetramerize and cut the two DNA sequences in a concerted manner was developed independently at least two times in the evolution of the PD-DxK superfamily of REases. The model of SfiI will also serve as a convenient platform for further experimental analyses.
Time-lapse analysis of potential cellular responsiveness to Johrei, a Japanese healing technique
Authors: Taft Ryan , Moore Dan , Yount Garret
Published: January 2005

Background

Johrei is an alternative healing practice which involves the channeling of a purported universal healing energy to influence the health of another person. Despite little evidence to support the efficacy of such practices the use of such treatments is on the rise.

Methods

We assessed cultured human cancer cells for potential responsiveness to Johrei treatment from a short distance. Johrei treatment was delivered by practitioners who participated in teams of two, alternating every half hour for a total of four hours of treatment. The practitioners followed a defined set of mental procedures to minimize variability in mental states between experiments. An environmental chamber maintained optimal growth conditions for cells throughout the experiments. Computerized time-lapse microscopy allowed documentation of cancer cell proliferation and cell death before, during and after Johrei treatments.

Results

Comparing eight control experiments with eight Johrei intervention experiments, we found no evidence of a reproducible cellular response to Johrei treatment.

Conclusion

Cell death and proliferation rates of cultured human cancer cells do not appear responsive to Johrei treatment from a short distance.
Supporter or obstructer; experiences from contact person activities among Swedish women with breast cancer
Authors: Carlsson Christina , Nilbert Mef , Nilsson Kerstin
Published: January 2005

Background

Swedish patient associations for breast cancer patients (PABCPs) offer patients with breast cancer unlimited meetings with a breast cancer survivor, a contact person (CP). We applied the voluntary action perspective in this interview study with members of Swedish PABCPs in order to explore how women with breast cancer experienced their contact with a CP from a PABCP.

Methods

Audio-taped narratives from 8 women were analysed using Reissman's monitoring and Gee's analysis structure.

Results

Three themes appeared: 1. Shared experiences give new perspectives on having cancer, 2. Feelings of isolation are a part of the identity of the illness and 3. Relations with others enable self-help. However, the relationship with the CP is sensitive to timing, correct information and understanding.

Conclusions

CPs act as sounding boards and should optimally have capacity for listening, gives support and act as partner in this conversation. On the other hand, CPs should be aware that their presence and limited general medical knowledge could at times disturb the patient's psychological recovery and strengthen feelings of isolation. Thus, PABCPs must be careful in selecting CPs and offer relevant educational activities related to the themes identified herein.
Life-threatening ventricular arrhythmia recognition by nonlinear descriptor
Authors: Sun Yan , Chan Kap Luk , Krishnan Shankar Muthu
Published: January 2005

Background

Ventricular tachycardia (VT) and ventricular fibrillation (VF) are ventricular cardiac arrhythmia that could be catastrophic and life threatening. Correct and timely detection of VT or VF can save lives.

Methods

In this paper, a multiscale-based non-linear descriptor, the Hurst index, is proposed to characterize the ECG episode, so that VT and VF can be recognized as different from normal sinus rhythm (NSR) in the descriptor domain.

Results

This newly proposed technique was tested using MIT-BIH malignant ventricular arrhythmia database. The relationship between the ECG episode length and the corresponding recognition performance was studied. The experiments demonstrated good performance of the proposed descriptor. An accuracy rate as high as 100% was obtained for VT/VF to be recognized from NSR; for VT and VF to be recognized from each other, the recognition accuracy varies from 84.24% to 100%. In addition, the results were compared favorably against those obtained using Complexity measure.

Conclusions

There is strong potential for using the Hurst index for malignant ventricular arrhythmia recognition in clinical applications.
Experimental study of the function of the excreted/secreted LeishmaniaLmSIR2 protein by heterologous expression in eukaryotic cell line
Authors: Sereno Denis , Vanhille Laurent , Vergnes Baptiste , Monte-Allegre Adriano , Ouaissi Ali
Published: January 2005

Background

In yeast and Caenorhabditis elegans, Silent Information Regulator (SIR2) proteins have been shown to be involved in ageing regulation. In Leishmania, the LmSIR2rp was originally isolated from the excreted/secreted material of the Leishmania parasites. Among the function(s) of this protein in Leishmania biology, we have documented its implication in parasite survival, and in particular in Leishmania amastigotes. In this paper we question the role of the excreted/secreted form of the protein. In particular we wonder if the Leishmania Sir2 homologue is involved in some aspect of its biological function(s), in various components and pathways, which could promote the host cell survival. To test this hypothesis we have mimicked an intracellular release of the protein through constitutive expression in mouse L929 fibrosarcoma cells.

Results

Our results demonstrate that the LmSIR2 protein was properly expressed by fibroblasts and that LmSIR2 is localized both in the cytoplasm and the nucleus of all the transformed cell clones. Unexpectedly, we found that cells expressing LmSIR2 presents reduced saturation cell density ranging from 40% to 60% and expressed an acidic (pH6.0) β-galactosidase activity, which is known to be a senescence biomarker. As a consequence, we observed that LmSIR2 positive fibroblasts were more permissive towards Leihmania infection.

Conclusions

LmSIR2 is able to substantially interfere with the host cell physiology. Thus, it is tempting to speculate that these modifications could help Leishmania to survive for a long period in a cell with reduced capacity to multiply or respond to immunologic stimuli. The potential implications of our finding during the in vivo infection process are discussed.
Adoptive transfer of dendritic cells modulates immunogenesis and tolerogenesis in a neonatal model of murine cutaneous leishmaniasis
Authors: Ponce Loida V , Corado José , Díaz Nilka L , Tapia Felix J
Published: January 2005

We evaluated the adoptive transfer of DCs on Leishmania (L.) mexicana-infected neonatal BALB/c mice. DCs were isolated and purified from the spleens of the following donor groups: a) Adult BALB/c mice infected during adulthood with L. (L) mexicana; b) Adult BALB/c mice infected during neonatal life; c) Healthy neonatal BALB/c mice; d) Healthy adult BALB/c mice. A neonatal model of infection, generated after inoculation with 5 × 105 promastigotes of L. (L) mexicana, was used as the infection control group. Sixteen hours after intraperitoneal transfer of DCs (1 × 103, 1 × 105, or 1 × 106 cells/ml), neonatal recipient BALB/c mice were infected. The adoptive transfer of DCs diminished disease progression in neonatal mice. This reduction depends on the quantity and provenance of transferred DCs, since the effect was more evident with high numbers of DCs from adult mice infected during adulthood and healthy neonatal mice. Protection was significantly reduced in animals receiving DCs from healthy adult mice but it was absent in mice receiving DCs from adult mice infected during neonatal life. These results suggest that genetic susceptibility to Leishmania infection can be modified during neonatal life, and that the period of life when antigens are encountered is crucial in influencing the capacity of DCs to induce resistance or tolerance.
A cost-minimization analysis of diuretic-based antihypertensive therapy reducing cardiovascular events in older adults with isolated systolic hypertension
Authors: Chen G John , Ferrucci Luigi , Moran William P , Pahor Marco
Published: January 2005

Background

Hypertension is among the most common chronic condition in middle-aged and older adults. Approximately 50 million Americans are currently diagnosed with this condition, and more than $18.7 billion is spent on hypertension management, including $3.8 billion for medications. There are numerous pharmacological agents that can be chosen to treat hypertension by physicians in clinical practices. The purpose of this study was to assess the cost of alternative antihypertensive treatments in older adults with isolated systolic hypertension (ISH).

Method

Using the Systolic Hypertension in the Elderly Program (SHEP) and other data, a cost-minimization analysis was performed. The cost was presented as the cost of number-needed-to treat (NNT) of patients for 5 years to prevent one adverse event associated with cardiovascular disease (CVD).

Result

It was found that the cost of 5 year NNT to prevent one adverse CVD event ranged widely from $6,843 to $37,408 in older patients with ISH. The incremental cost of the 5 year NNT was lower to treat older patients in the very high CVD risk group relative to patients in the lower CVD risk group, ranging from $456 to $15,511. Compared to the cost of the 5 year NNT of other commonly prescribed antihypertensive drugs, the cost of SHEP-based therapy is the lowest. The incremental costs of the 5 year NNT would be higher if other agents were used, ranging from $6,372 to $38,667 to prevent one CVD event relative to SHEP-based drug therapy.

Conclusion

Antihypertensive therapy that is diuretic-based and that includes either low-dose reserpine or atenolol is an effective and relatively inexpensive strategy to prevent cardiovascular events in older adults with isolated systolic hypertension. Use of the diuretic-based therapy is the most cost-effective in patients at high risk for developing cardiovascular disease.
QT interval prolongation related to psychoactive drug treatment: a comparison of monotherapy versus polytherapy
Authors: Sala Michela , Vicentini Alessandro , Brambilla Paolo , Montomoli Cristina , Jogia Jigar RS , Caverzasi Eduardo , Bonzano Alberto , Piccinelli Marco , Barale Francesco , De Ferrari Gaetano M
Published: January 2005

Background

Several antipsychotic agents are known to prolong the QT interval in a dose dependent manner. Corrected QT interval (QTc) exceeding a threshold value of 450 ms may be associated with an increased risk of life threatening arrhythmias. Antipsychotic agents are often given in combination with other psychotropic drugs, such as antidepressants, that may also contribute to QT prolongation. This observational study compares the effects observed on QT interval between antipsychotic monotherapy and psychoactive polytherapy, which included an additional antidepressant or lithium treatment.

Method

We examined two groups of hospitalized women with Schizophrenia, Bipolar Disorder and Schizoaffective Disorder in a naturalistic setting. Group 1 was composed of nineteen hospitalized women treated with antipsychotic monotherapy (either haloperidol, olanzapine, risperidone or clozapine) and Group 2 was composed of nineteen hospitalized women treated with an antipsychotic (either haloperidol, olanzapine, risperidone or quetiapine) with an additional antidepressant (citalopram, escitalopram, sertraline, paroxetine, fluvoxamine, mirtazapine, venlafaxine or clomipramine) or lithium. An Electrocardiogram (ECG) was carried out before the beginning of the treatment for both groups and at a second time after four days of therapy at full dosage, when blood was also drawn for determination of serum levels of the antipsychotic.

Statistical analysis included repeated measures ANOVA, Fisher Exact Test and Indipendent T Test.

Results

Mean QTc intervals significantly increased in Group 2 (24 ± 21 ms) however this was not the case in Group 1 (-1 ± 30 ms) (Repeated measures ANOVA p < 0,01). Furthermore we found a significant difference in the number of patients who exceeded the threshold of borderline QTc interval value (450 ms) between the two groups, with seven patients in Group 2 (38%) compared to one patient in Group 1 (7%) (Fisher Exact Text, p < 0,05).

Conclusions

No significant prolongation of the QT interval was found following monotherapy with an antipsychotic agent, while combination of these drugs with antidepressants caused a significant QT prolongation. Careful monitoring of the QT interval is suggested in patients taking a combined treatment of antipsychotic and antidepressant agents.
Immunochemotherapy With Rituximab and Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone Significantly Improves Response and Time to Treatment Failure, But Not Long-Term Outcome in Patients With Previously Untreated Mantle Cell Lymphoma: Results of a Prospective Randomized Trial of the German Low Grade Lymphoma Study Group (GLSG)
Authors: Lenz Georg , Dreyling Martin , Hoster Eva , Wörmann Bernhard , Dührsen Ulrich , Metzner Bernd , Eimermacher Hartmut , Neubauer Andreas , Wandt Hannes , Steinhauer Hjalmar , Martin Sonja , Heidemann Else , Aldaoud Ali , Parwaresch Reza , Hasford Joerg , Unterhalt Michael , Hiddemann Wolfgang
Published: January 2005

Purpose

Mantle cell lymphoma (MCL) is characterized by a poor prognosis with a low to moderate sensitivity to chemotherapy and a median survival of only 3 to 4 years. In an attempt to improve outcome, the German Low Grade Lymphoma Study Group (GLSG) initiated a randomized trial comparing the combination of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) and rituximab (R-CHOP) with CHOP alone as first-line therapy for advanced-stage MCL.

Patients and Methods

One hundred twenty-two previously untreated patients with advanced-stage MCL were randomly assigned to six cycles of CHOP (n = 60) or R-CHOP (n = 62). Patients up to 65 years of age achieving a partial or complete remission underwent a second randomization to either myeloablative radiochemotherapy followed by autologous stem-cell transplantation or interferon alfa maintenance (IFNα). All patients older than 65 years received IFNα maintenance.

Results

R-CHOP was significantly superior to CHOP in terms of overall response rate (94% v 75%; P = .0054), complete remission rate (34% v 7%; P = .00024), and time to treatment failure (TTF; median, 21 v 14 months; P = .0131). No differences were observed for progression-free survival. Toxicity was acceptable, with no major differences between the two therapeutic groups.

Conclusion

The combined immunochemotherapy with R-CHOP resulted in a significantly higher response rate and a prolongation of the TTF as compared with chemotherapy alone. Hence, R-CHOP may serve as a new baseline regimen for advanced stage MCL, but needs to be further improved by novel strategies in remission.