bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of astacin‐like metalloproteases in animals and their function in development
Authors: Möhrlen Frank , Maniura Melanie , Plickert Günter , Frohme Marcus , Frank Uri
Published: February 2006

SUMMARY
Astacin‐like metalloproteases are ubiquitous in the animal kingdom but their phylogenetic relationships and ancient functions within the Metazoa are unclear. We have cloned and characterized four astacin‐like cDNAs from the marine hydroid Hydractinia echinata and performed a database search for related genes in the draft genome sequence of the sea anemone Nematostella vectensis. These sequences and those of higher animals' astacins were subjected to phylogenetic analysis revealing five clusters within the Eumetazoa. The bone morphogenetic protein‐1/tolloid‐like astacins were represented in all eumetazoan phyla studied. The meprins were only found in vertebrates and cnidarians. Two clusters were taxon‐specific, and one cluster represented astacins, which probably evolved after the split of the Cnidaria. Interestingly, grouping of astacins according to the protease catalytic domain alone resulted in clusters of proteins with similar overall domain architecture. The Hydractinia astacins were expressed in distinct cells during metamorphosis and some also during wound healing. Previously characterized cnidarian astacins also act during development. Based on our phylogeny, however, we propose that the developmental function of most of them is not homologous to the developmental function assigned to higher animals' astacins.
A Tale of Two Fears: Exploring Media Depictions of Nuclear Power and Global Warming
Authors: Palfreman Jon
Published: February 2006

Advanced technologies like nuclear power and looming environmental threats such as global climate change present major policy challenge for modern cultures. Public policy about such crucial and complex issues depends on public attitudes, which, in turn, tend to be strongly affected by mass media coverage. How “well” has the mass media portrayed these two evolving risk stories? Employing perspectives from both journalism and social science, this article will first review the history of mass media coverage of each topic, then analyze their differences.
Western Wildfires: A Policy Change Perspective
Authors: Davis Charles
Published: February 2006

My research objective in this article is to analyze policy change affecting wildfire suppression programs administered by the United States Forest Service and the United States Department of the Interior. Using a variant of the punctuated equilibrium approach, a content analysis of New York Times stories dealing with wildfires over the past two decades was examined in relation to both administrative and legislative policy changes. I conclude by suggesting that administrative shifts were undertaken by federal land administrators in response to crises and media attention to protect decisional autonomy as well as forest resources, while the architect of legislative change was a president taking advantage of the combined effects of increasingly intense wildfire seasons, demographic shifts involving the movement of people and structures to the high‐risk wildland urban interface areas, greater media scrutiny, and pressure to act from wildfire weary constituencies.
Managing Risk and Regulation in European Food Safety Governance
Authors: Caduff Ladina , Bernauer Thomas
Published: February 2006

This article focuses on the state of European food safety governance and offers a view on possible future courses of regulatory policymaking. We begin by examining the deficiencies of the current multilevel governance system in European Union (EU) food safety policy, with an empirical focus on Hazard Analysis and Critical Control Point (HACCP) systems. We then submit that a regulatory agency model (centralization) might perform better than multilevel governance or renationalization in terms of reducing business uncertainty, promoting food safety enhancing innovation, and improving consumer trust in the food supply. Hence it would make European food markets more resilient to recurrent food safety crises. We also argue that the EU's precautionary approach as applied to some areas of food safety risks is tied to legitimacy enhancing objectives of EU institutional actors. Assuming that supply‐side rents will change over time, we submit that emphasis of regulatory impact analysis (i.e., cost benefit considerations) is likely to increase.
Is a Computer Worth a Thousand Books? Internet Access and the Changing Role of Public Libraries
Authors: Flamm Anindya Chaudhuri and Kenneth S.
Published: February 2006

The ongoing debate on the “digital divide” is centered on improving Internet home‐access penetration rates through two instruments, price subsidies and capital subsidies. Subsidizing home access can be expensive and difficult because of the inherent difficulty of identifying target households. Increasing the availability of public access terminals instead can be an effective way for achieving universal access. The analysis of this article considers public libraries because of their national reach and existing Internet service offerings to users. It finds strong evidence of a need‐based use of access facilities at these libraries, and also identifies a clear increasing trend in visits over time by patrons for getting online. Upgrading and maintaining these facilities would be a better use of funds than indiscriminately providing subsidies to households.
Do domatia mediate mutualistic interactions between coffee plants and predatory mites?
Authors: Matos Cláudia H.C. , Pallini Angelo , Chaves Fredson F. , Schoereder José H. , Janssen Arne
Published: February 2006

Many plant species possess structures on their leaves that often harbour predatory or fungivorous mites. These so‐called domatia are thought to mediate a mutualistic interaction; the plant gains protection because mites decimate plant pathogenic fungi or herbivores, whereas the mites find shelter in the domatia. We tested this hypothesis using two species of coffee (Coffea spp.) plants that posses domatia consisting of small cavities at the underside of the leaves, and which often harbour mites. We assessed densities of domatia, of the predatory mite Iphiseiodes zuluagai Denmark and Muma (Acari: Phytoseiidae) and of herbivorous mites Oligonychus ilicis (McGregor) (Acari: Tetranychidae) and Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) on Coffea arabica L. (Rubiaceae) and Coffea canephora Pierre in the field. Over a period of 50 days, C. arabica harboured on average 7.5 times more predatory mites and 0.4–0.66 fewer prey mites than C. canephora. Hence, the higher density of predatory mites on C. arabica could not be explained by higher densities of prey. However, the density of domatia on C. arabica was on average 1.65 times higher than on C. canephora, and within each species, leaves with higher densities of domatia also harboured more predators. This suggests a positive effect of domatia on predatory mites. In the laboratory, survival of adult female predatory mites on leaves of C. arabica with open domatia was indeed significantly higher than on leaves with closed domatia. Hence, predatory mites benefited from the domatia. However, plants with higher densities of domatia did not harbour fewer herbivores. Taken together, our study only provides partial evidence for a mutualistic interaction between coffee plants and predatory mites, mediated by domatia.
Diurnal pattern of death and sporulation in Entomophaga maimaiga‐infected Lymantria dispar
Authors: Nielsen C. , Hajek A.E.
Published: February 2006

Entomophaga maimaiga Humber, Shimazu, et Soper (Zygomycotina: Entomophthoraceae) is a naturally occurring obligate fungal pathogen specific to gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae) larvae. This fungus is considered the most important natural enemy of this pest insect in North America and Asia. A critically important step for the development of E. maimaiga epizootics is the transmission of propagules to healthy larvae, a process known to require high humidity. Some pathogens are known to manipulate the time of day that hosts die so that propagules are produced to maximize chances of survival and thus enhance transmission. The objective of this study was to assess whether E. maimaiga manipulates L. dispar to die at a certain time of day. Laboratory bioassays were conducted at 15 and 20 °C to record the 24‐h activity pattern of death and sporulation exhibited under an L14:D10 photoperiod and 100% r.h. by four isolates of E. maimaiga in its host L. dispar. Events were recorded every 4 h. Our results clearly demonstrate that E. maimaiga‐infected L. dispar larvae die mainly in the afternoon and that the fungus sporulates during the night. The rhythm was independent of the fungal isolate tested and type of spores produced after larval death. By raising the temperature from 15 to 20 °C, the peak death time narrowed and sporulation was initiated earlier at night.
A GIS‐based approach for areawide pest management: the scales of Lygus hesperus movements to cotton from alfalfa, weeds, and cotton
Authors: Carrière Yves , Ellsworth Peter C. , Dutilleul Pierre , Ellers‐Kirk Christa , Barkley Virginia , Antilla Larry
Published: February 2006

Understanding the effect of cropping patterns on population dynamics, dispersal, and habitat selection of insect pests has been an unresolved challenge. Here, we studied the western tarnished plant bug, Lygus hesperus (Knight) (Heteroptera: Miridae), in cotton during early summer in central Arizona. We used a general approach based on global positioning system (GPS) and geographic information system (GIS) technologies combined with spatial statistics to assess the maximum distance at which forage and seed alfalfa, fallow fields with weeds, and cotton affect L. hesperus population density. Using a set of 50 cotton fields as focal fields, we found that forage and seed alfalfa as well as weeds acted as L. hesperus sources for these cotton fields. The source effect did not extend beyond 375, 500, and 1500 m for forage alfalfa, weeds, and seed alfalfa, respectively. Conversely, cotton fields acted as L. hesperus sinks, but this effect did not extend further than 750 m from the focal cotton fields. These findings suggest that specific spatial arrangements of these field types could reduce L. hesperus damage to cotton. The spatially explicit approach used here provides a direct evaluation of the effects of agroecosystem heterogeneity on pest population dynamics, dispersal, and habitat selection, which is a significant asset for the development and improvement of areawide pest management.
Effect of plant architecture and hail nets on temperature of codling moth habitats in apple orchards
Authors: Kührt Ute , Samietz Jörg , Dorn Silvia
Published: February 2006

Plant architecture of apple trees in commercial orchards was rapidly changed from traditional tall trees to dwarf trees to optimize yield and fruit quality. Additionally, hail nets are widely used to prevent yield loss by hail. These changes are expected to considerably influence the orchard microclimate and thus the developmental rates of pest insects in apple. However, these relationships have not yet been fully elucidated. The present study was conducted over the seasonal cycle to investigate the influence of plant architecture and hail nets on the habitat temperatures of the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), in apple, Malus domestica Borkh. (Rosaceae). Within the canopies, leaf area index (LAI) and global site factor (GSF) were quantified using hemispherical photography. Temperature was analysed for the main habitats of the different codling moth stages, i.e., air within the canopy, bark of tree stems, and apple fruit. In dwarf trees, LAI was lower, leading to a higher GSF than in tall trees. Hail nets did not influence LAI and GSF. Results for dwarf trees compare as follows with those for tall trees: Average air temperatures within the canopy were 0.7 °C higher during daytime, whereas 0.4 °C lower at night. Mean surface temperatures of bark were 0.9 °C higher on sunny and 0.4 °C on overcast days. Mean surface temperatures of apple fruits were 1.8–2.7 °C higher on sunny days, but 0.6 °C cooler on overcast days. The effect of hail nets was confined to a reduction of the air temperature within the canopy by approximately 0.2–0.8 °C. Bark and apple surface temperatures were not significantly affected. Based on the temperature differences in the habitats considered, the calculated development of the codling moth in dwarf trees was on average 3 days faster than in tall trees. The calculations imply a negligible effect of hail nets on codling moth development.
IL‐2 and IL‐10 serum levels in HIV‐1‐infected patients with or without active antiretroviral therapy
Authors: ORSILLES MIGUEL ÁNGEL , PIERI ELSA , COOKE PAULA , CAULA CINTHYA
Published: February 2006

We analyzed IL‐2 and IL‐10 serum levels in 26 HIV‐1‐infected patients naive of antiretroviral treatment and in 34 patients receiving highly active antiretroviral therapy (HAART). All patients without treatment were asymptomatic. When they were stratified according to levels of CD4+ T cells, IL‐2 levels were significantly increased in patients with ≥200 CD4+/μl and IL‐10 levels were significantly increased in patients with <200 CD4+/μl compared to controls. A significant negative correlation was observed between IL10 levels and CD4+ T‐cell counts. No correlation was observed between IL‐2 and IL‐10 levels and viral load due to the wide range of variability in the number of HIV copies/ml present in the different patients. However, IL‐2 levels were higher in patients with high viral load than in patients with low viral load. In patients with HAART, IL‐2 and IL‐10 levels were similar to the control group and no differences were detected respecting CD4+ T cells counts and viral load. Our findings show that the modifications in IL‐2 and IL‐10 serum levels in HIV‐1‐infected patients naive of antiretroviral treatment are associated with the progression of immunological damage. Furthermore, they show a dysbalance of type‐1/type‐2 cytokines with an involvement of type‐2 cytokines in later stages of HIV infection. Cytokine dysregulation can be reversed by HAART in the context of immune restoration and viral suppression.
The invasive behaviour of prostatic cancer cells is suppressed by inhibitors of tyrosine kinase
Authors: SKOGSETH HAAKON , LARSSON ERIK , HALGUNSET JOSTEIN
Published: February 2006

Proteolytic enzymes, and especially urokinase plasminogen activator (uPA), play an important role in tumour invasion and metastasis. Previously we demonstrated that the production of urokinase plasminogen activator (uPA) was decreased by several tyrosine kinase inhibitors (TKI) in two prostatic carcinoma cell lines. The effect of the two TKI genistein and tyrphostin AG‐1478 was investigated in the prostate carcinoma cell lines PC‐3 and DU‐145. A reconstituted basal lamina (Matrigel) was used as a migration barrier. The production of matrix metalloproteinases (MMP) was also measured. Roles of plasminogen and uPA were examined. Cell invasion was increased by plasminogen, but this enhanced cell migration was counteracted by TKI treatment. The increased cell invasion induced by plasminogen was decreased by at least 60% in both cell lines when α‐2 anti‐plasmin was added to the assay. Cells in the absence of plasminogen were not affected by TKI. External uPA failed to regenerate the decreased cell invasion caused by TKI. The production of MMP was inhibited by both TKI. Our results indicate a possible role of TKI as inhibitors of cancer cell invasion by inhibiting uPA and MMP production.
Tenascin‐C expression in Merkel cell carcinoma lymph node metastasis
Authors: KOLJONEN VIRVE , BÖHLING TOM , TUKIAINEN ERKKI , HAGLUND CAJ , JAHKOLA TIINA
Published: February 2006

Expression of tenascin‐C (Tn‐C) has been shown to correlate with invasion and metastasis in Merkel cell carcinoma (MCC). Cytokeratin‐20 (CK‐20) is used in differential diagnostics of the primary tumour. The aim of this study was to demonstrate the expression of Tn‐C in MCC lymph node metastases. Immunohistochemical staining was performed for five metastatic lymph nodes using a monoclonal antibody against Tn‐C and CK‐20. All five metastatic lymph nodes expressed Tn‐C. The expression concentrated around the vascular structures, invasion borders and fibrotic septae. One of the metastatic lymph nodes was strongly positive for CK‐20 while the others showed a focal or negative pattern. The normal lymphoid tissue was negative for Tn‐C. Tn‐C detected metastatic MCC tissue within the lymph nodes undisputedly. There was a clear distinction between the metastatic and normal lymphatic tissue. Furthermore, invasion to the surrounding tissue was easily demonstrated. Contrary to previous studies, CK‐20 expression seemed to fluctuate.
Virulence markers of LCR plasmid in Indian isolates of Yersinia pestis
Authors: KHUSHIRAMANI REKHA , TUTEJA URMIL , SHUKLA JYOTI , PANIKKAR ANUPAMA , BATRA HARSH VARDHAN
Published: February 2006

Presence of 10 important yop genes in Yersinia pestis isolates (18 in number) of Indian origin from 1994 plague outbreak regions of Maharashtra (6 Rattus rattus & Tetera indica rodents) and Gujarat (11 from human patients, 1 from R. rattus) and from plague endemic regions of the Deccan plateau (8 from T. indica) was located by PCR and specific enzyme immunoassay. PCRs were standardized for six effector yops (YopE, YopH, YopJ, YopM, YopO and YopT), three translocator yops (YopB, YopD and YopK) and a regulator LcrV gene. Amplification of all the 10 yop genes was observed in isolates recovered from pneumonic patients and in 5 of 7 rodents from outbreak regions. Among these, amplification of the yopD gene was absent in all eight isolates, and that of yopM in all except one (10R). One of the isolates from rodents of the Deccan plateau (24H) was consistently negative for all the yops. Cloning and expression of truncated yopM (780 bp), yopB (700 bp) and lcrV (796 bp) genes in pQE vectors with SG13009 host cells yielded recombinant proteins for generation of monoclonal antibodies for further use in enzyme immunoassay. Ten stable reactive clones for YopB, nine for YopM and six for LcrV were obtained, all of them exhibiting specific reactions only to Y. pestis. Testing of 26 Y. pestis isolates by monoclonal antibody dot‐ELISA and Western blotting provided results identical to PCR, suggesting that the isolates that failed to show PCR amplification also had no expression of their respective proteins. The Y. pestis isolates of outbreak regions had their virulence factors intact in the LCR plasmid. Yersinia pestis isolates recovered from rodents of the Deccan plateau were relatively heterogeneous. It appears that a long residency of Y. pestis of nearly 100 years in the enzootic plague foci has resulted in shedding of virulence genes in the LCR plasmid region in a fairly large proportion of the organisms, possibly due to natural recombination.
Long‐term treatment of pigs with low doses of monoclonal antibodies against porcine CD4 and CD8 antigens
Authors: LOHSE LOUISE , NIELSEN JENS , ERIKSEN LIS
Published: February 2006

In vivo depletion of lymphocyte subsets allows investigation of the role of specific subsets in protective immunity. In the present study we evaluated the effects of long‐term, low‐dose treatment with murine monoclonal antibodies (mAbs) against porcine CD4 and CD8 surface antigens on lymphocyte subsets in pigs. Four‐week‐old pigs were treated by intramuscular injections of hybridoma cell culture supernatants containing anti‐CD mAbs twice a week for a period of 5 weeks. The immunomodulatory effects of the treatments were assessed by flow cytometry (FCM) analysis of peripheral blood lymphocytes. Treatment with the anti‐CD4 mAb almost completely eliminated the CD4+ T‐cell subset from the circulation after 2 weeks of therapy. This depletion persisted until the end of the experimental period 5 weeks after initiated therapy. Treatment with the anti‐CD8 mAb was less effective, reducing the CD8+ T‐cell subset in peripheral blood by approximately 50% of the initial level after 3 weeks of therapy. Further, the anti‐CD8 mAb‐treated pigs showed a parallel increase in the CD4+ T‐cell subset from day 7. Two‐colour FCM analysis indicated that a shift in phenotype from single‐positive CD4+/CD8− to double‐positive CD4+/CD8+ T‐cells might have occurred in these pigs. In the present experiment we demonstrated specific modulation of the peripheral blood T‐lymphocyte population in pigs with continuous low‐dose injections of specific mAb. The ability to modulate individual T‐cell subsets should provide a method to elucidate their functionality in protection against infectious disease.
Molecular epidemiology of Neisseria gonorrhoeae– identification of the first presumed Swedish transmission chain of an azithromycin‐resistant strain
Authors: LUNDBÄCK DAVID , FREDLUND HANS , BERGLUND TORSTEN , WRETLIND BENGT , UNEMO MAGNUS
Published: February 2006

In the present study, 10 azithromycin‐resistant Neisseria gonorrhoeae isolates from 6 Swedish male patients in 2004, 3 sporadic Swedish azithromycin‐resistant N. gonorrhoeae isolates from recent years and one Swedish N. gonorrhoeae isolate from 2003 that was susceptible to azithromycin but assigned the same serological variant (serovar), i.e. IB‐37, as the isolates from 2004 were included. The isolates were characterized phenotypically using antibiograms and serovar determination and genetically with pulsed‐field gel electrophoresis (PFGE), entire porB gene sequencing and N. gonorrhoeae multiantigen sequence typing (NG‐MAST). The epidemiological information and the results of the thorough phenotypic characterisation and genetic characterisation identified the first presumed domestic transmission of one azithromycin‐resistant N. gonorrhoeae strain in Sweden in 2004. This stresses the need for continuous surveillance of the antibiotic susceptibility of N. gonorrhoeae in order to identify emergence of new resistance, monitor the changing patterns of the susceptibility, and be able to update treatment recommendations on a regular basis.
Comparison of workflow and accuracy of identification and antimicrobial susceptibility testing of clinical isolates of Enterobacteriaceae, Pseudomonas aeruginosa and enterococci by Vitek 2 and routine methods
Authors: RANTAKOKKO‐JALAVA KAISU , ELO‐LEHTONEN EIJA , MEURMAN OLLI
Published: February 2006

Three hundred and fifty‐three consecutive urine cultures growing Enterobacteriaceae, Pseudomonas aeruginosa or enterococci were subjected to parallel identification (ID) and antimicrobial susceptibility testing (AST) by Vitek 2 and routine methods, including simple screening tests or API 20 E for ID and standardized disc diffusion for AST. Accuracy of results, technician hands‐on time required by both methods and time to results were compared. Vitek 2 correctly identified 322 (94.7%) of the 340 gram‐negative isolates and 17 (81%) of the 21 Enterococcus faecalis strains. AST by Vitek 2 and disc diffusion gave category agreement for 4,058 (95.5%) of 4,248 organism‐antimicrobial agent combinations. With MIC determination by E‐test as reference, AST by Vitek 2 and disc diffusion produced 15 and 3 very major errors, respectively. Six (40%) of the fifteen very major errors by Vitek 2 were associated with trimethoprim‐sulfamethoxazole. With an average of 22 specimens processed per day, use of Vitek 2 saved 80 min per day of technician hands‐on time as compared to routine methods. Regarding the cost of hands‐on worktime and consumables, use of Vitek 2 for identification of Escherichia coli‐screened Enterobacteriaceae saved 0.70 p per sample in comparison to API 20 E. More than 80% of Enterobacteriaceae introduced to Vitek 2 in the morning could be reported by 16:00.
Bilateral hamartoma arising in axillary accessory mammary glands
Authors: KURODA N. , GOISHI K. , OHARA M. , HIROUCHI T. , MIZUMO K. , NAKAGAWA K.
Published: February 2006

A 57‐year‐old Japanese woman presented with a lump, originally noticed 10 years previously, in both axillary regions. Histologically, the axillary tumors consisted of a random admixture of ducts, lobules and fibrous stroma with predominant adipose tissue. This is the first case of bilateral ectopic hamartoma arising in the axillary regions. Surgeons and pathologists should be aware that ectopic breast hamartoma can occur in both axillary regions.
Identification of transcriptional targets associated with the expression of p210 Bcr‐Abl
Authors: Hickey Fionnuala B. , Cotter Thomas G.
Published: February 2006

Abstract:  Objectives: Chronic myeloid leukaemia is caused by the expression of the p210 Bcr‐Abl fusion protein which results from the Philadelphia translocation, t(9;22). This oncogene has been the focus of extensive research. However, the molecular mechanisms responsible for the haematological malignancy are not fully understood. The main objective of the current study was to identify novel transcriptional targets of Bcr‐Abl. Methods: In order to achieve this, microarrays were employed in order to conduct a genome‐wide expression analysis comparing 32D cells with a transfected clone expressing high levels of p210 Bcr‐Abl. Quantitative RT‐PCR was employed in order to confirm the observed increase/decrease in expression for a number of the deregulated genes. Results and conclusions: This comparison identified 138 genes of known function showing altered expression in response to Bcr‐Abl‐mediated signalling. Among the genes found to be upregulated in response to p210 Bcr‐Abl were aldolase 1A and phosphofructokinase, both of which encode key enzymes in the glycolytic pathway. As a consequence of this, we demonstrate that the rate of glycolysis is significantly increased in Bcr‐Abl expressing cells in a PI3K‐dependent manner. Our results also indicate altered expression of genes involved in cell proliferation, cell adhesion and cell signalling.
Infections during induction therapy of childhood acute lymphoblastic leukemia – no association to mannose‐binding lectin deficiency
Authors: Lausen Birgitte , Schmiegelow Kjeld , Andreassen Bente , Madsen Hans O. , Garred Peter
Published: February 2006

Abstract:  Objectives: Infection during the induction phase of childhood acute lymphoblastic leukemia (ALL) is a major cause of morbidity and mortality. Several studies have indicated that genetically determined low serum levels of mannose‐binding lectin (MBL), a component of innate immunity, are associated with increased risk for infections in patients receiving chemotherapy. Thus, these patients have been proposed to be candidates for MBL replacement therapy. Methods: In a population‐based cohort of 137 children with ALL treated at a single pediatric hematology‐oncology center with an almost identical chemotherapy regimen, we studied the relationship between polymorphisms in the MBL gene (MBL2) and the MBL2 promoter and the risk of infections during the first 50 d of induction therapy. Results: No increased frequency of infection was seen for the children with genotypes encoding serum low levels of MBL. A higher incidence of fever (P < 0.004), infectious events (P = 0.025), days with neutropenia (P < 0.001) and a higher frequency of antimicrobial therapy (P = 0.0007) were seen in the young age group (<2.5 yr) compared with the older age group (≥2.5 yr), independent of the MBL genotype. Conclusions: MBL deficiency did not influence the frequency of infections in children receiving induction chemotherapy for ALL, not even in the youngest children (<2.5 yr) whom we found to have the highest risk for infections.
Role of stromal‐derived factor‐1 in the hematopoietic‐supporting activity of human mesenchymal stem cells
Authors: Van Overstraeten‐Schlögel Nancy , Beguin Yves , Gothot André
Published: February 2006

Abstract:  Mesenchymal stem cells (MSC) have the ability to support and maintain hematopoiesis in vitro. However, mechanisms implicated in this support are not fully characterized. In the present study, the role of stromal‐derived factor‐1 (SDF‐1)/CXCR4 axis in the interactions between MSC and hematopoietic stem/progenitor cells (HSPC) was studied. Human bone marrow MSC were plated as feeder layers in Dexter‐type long‐term cultures (LTC) with human cord blood CD34+ HSPC. Cultures were supplemented weekly with neutralizing antibodies against CXCR4 or SDF‐1 for 5 wk. LTC‐initiating cell (IC) activity was strongly dependent on the SDF‐1/CXCR4 axis, as both antibodies significantly decreased secondary colony‐forming cell production. To assess the effect of SDF‐1/CXCR4 axis on progenitor cell proliferation, LTC‐IC killing assays were carried out: in LTC of CD34+ cells in contact with MSC, treatment with anti‐CXCR4 antibody significantly reduced the number of cycling progenitors. These results indicate that the SDF‐1/CXCR4 axis promotes HSPC proliferation in contact with MSC. Interestingly, when HSPC were separated from MSC by a semipermeable membrane, LTC‐IC activity became CXCR4 independent. Multiplex analysis of MSC‐conditioned medium revealed that in addition to SDF‐1, MSC produced stimulatory and inhibitory factors, such as interleukin (IL)‐6, IL‐11, granulocyte macrophage‐colony stimulating factor as well as monocyte‐chemoattractant protein‐1. Altogether, human MSC support hematopoiesis in Dexter‐type cultures through the activation of the SDF‐1/CXCR4 axis. Our data further suggest that SDF‐1 stimulates retention of HSPC in MSC niches which expose them to stimulatory and inhibitory factors in a paracrine manner.
Melanogenesis and evidence for melanosome transport to the plasma membrane in a CD83+ teleost leukocyte cell line
Authors: Haugarvoll Erlend , Thorsen Jim , Laane Morten , Huang Qirong , Koppang Erling Olaf
Published: February 2006

Visceral organs of ectothermic vertebrates harbour melanin‐containing leukocytes termed melanomacrophages. These cells are thought to participate in immune reactions and free‐radical trapping. In teleosts, the melanin‐producing ability of melanomacrophages has hitherto not been confirmed by molecular techniques. Here, a leukocyte marker and the apparatus for melanosome production and transport were investigated in an Atlantic salmon (Salmo salar) pronephros‐derived mononuclear leukocyte (SHK‐1) cell line. The SHK‐1 cells expressed transcripts specific for a mammalian CD83 homologue, a standard surface marker for activated or differentiated dendritic cells, and dopachrome tautomerase/tyrosinase‐related protein‐2, a melanocyte specific enzyme essential for melanin production. Reduction potential of melanin or its precursors was demonstrated histochemically after prolonged cultivation. Ultrastructural investigations revealed tyrosinase and acid phosphate activity in identical organelles and BSA‐gold co‐localized with multilamellar melanosomes after 2 h internalization. Apparently, melanosomes were transported and released through periodically occurring tubules fusing with the plasma membrane. Video monitoring revealed filopodia and macropinocytosis. These results showed that the SHK‐1 cell line is capable of melanogenesis and melanosome secretion. Melanin‐producing cells in teleost pronephros may represent a distinct CD83+ leukocyte population consisting of phylogenetically relict multifunctional cells. This is the first report of a melanin‐producing leukocyte cell‐line.
Effect of adoptive transfer of antigen‐specific B cells on periodontal bone resorption
Authors: Harada Y. , Han X. , Yamashita K. , Kawai T. , Eastcott J. W. , Smith D. J. , Taubman M. A.
Published: February 2006

Background and Objectives:  Host immune responses to periodontal pathogens have been considered to contribute to the alveolar bone destruction in periodontitis. However, the role of B lymphocytes in the pathogenesis of periodontal bone loss is not clear.

Methods:  We examined the effect of adoptive transfer of antigen‐specific B cells from rat spleens on experimental periodontal bone resorption. Donor rats were immunized intraperitoneally (i.p.) with formalin‐killed Actinobacillus actinomycetemcomitans. Antigen‐specific B cells were prepared from splenocytes by first binding CD43+ cells to Petri dishes coated with anti‐CD43 antibody to remove T cells, and non‐binding cells were passed through a nylon wool column to deplete accessory cells. The retained cells were then collected and bound to A. actinomycetemcomitans‐coated Petri dishes for enrichment of A. actinomycetemcomitans‐binding B cells (AAB). A. actinomycetemcomitans non‐binding B cells (ANB) and B cells from non‐immunized donor rats (NIB) were also collected from these procedures. Each type of B cell was injected into a group of recipient rats that were then orally infected with live A. actinomycetemcomitans.

Results:  At termination, the antibody levels to A. actinomycetemcomitans in serum and gingival wash fluids were significantly higher in the recipients transferred with AAB when compared to the recipients transferred with ANB or NIB. A markedly elevated number of antibody‐forming cells were observed in the spleens of the recipients transferred with AAB, and these recipient rats also exhibited significantly increased bone resorption when compared to the other groups.

Conclusions:  It is suggested that B cells can contribute to periodontal bone resorption and that antigen‐triggering of B cells is required for the bone resorption.
Recombinant human growth/differentiation factor‐5 (rhGDF‐5) induced bone formation in murine calvariae
Authors: Yoshimoto Takehiko , Yamamoto Matsuo , Kadomatsu Hideshi , Sakoda Kenji , Yonamine Yutaka , Izumi Yuichi
Published: February 2006

Objectives:  Growth/differentiation factor‐5 (GDF‐5), a member of the transforming growth factor‐β superfamily, shows a close structural relationship to bone morphogenetic proteins and plays crucial roles in skeletal morphogenesis. Recombinant human (rh) GDF‐5 was reported as a suitable factor for enhancing healing in bone defect and inducing ectopic bone formation. The purpose of the present study was to investigate the mechanism of bone formation induced by rhGDF‐5 in murine calvariae by radiological, histological and immunohistochemical methods. Cell proliferation was also examined in vitro.

Material and methods:  Cells including primary osteoblasts, periosteum cells and connective tissue fibroblasts were isolated enzymatically from neonatal murine calvariae or head skin. In the presence or absence of rhGDF‐5, cell proliferation was estimated by tetrazolium reduction assay. To examine the mechanism of osteoinduction, rhGDF‐5/atelocollagen (AC) composite or 0.01 N HCl/AC composite were injected into murine calvariae subcutaneously. Tissue was examined radiologically, histologically and immunohistochemically.

Results:  In the presence of rhGDF‐5, proliferation of primary osteoblasts, periosteum cells, and connective tissue fibroblasts was increased significantly in culture. Immunohistochemical observations showed cells at the site injected with rhGDF‐5/AC displayed immunoreactivity for proliferating cell nuclear antigen (PCNA). Newly formed bone‐ and cartilage‐like tissue contained chondrocyte osteocyte and osteoclastic cells, and were immunoreactive for both type I and II collagen.

Conclusion:  Exposure to GDF‐5 promotes proliferation and differentiation of calvarial cells, which give rise to ectopic bone formation.
DX‐9065a inhibits proinflammatory events induced by gingipains and factor Xa
Authors: Matsushita Kenji , Imamura Takahisa , Tomikawa Munehiro , Tancharoen Salunya , Tatsuyama Syouko , Maruyama Ikuro
Published: February 2006

Objective:  Arginine‐specific cysteine proteases (Rgps) from Porphyromonas gingivalis are important virulent factors of periodontal diseases. However, there is no therapeutic drug that inhibits proinflammatory events induced by these enzymes. In this study, we investigated proinflammatory activities of Rgps and activated coagulation factor X (FXa) and examined the effect of DX‐9065a, a new selective inhibitor of FXa, on proinflammatory events induced by these proteinases.

Methods:  Human gingival fibroblasts were stimulated with Rgps and FXa in the presence or absence of DX‐9065a, and then interleukin‐6 (IL‐6) and matrix metalloproteinase‐1 (MMP‐1) release, their mRNA expression, and nuclear factor κB (NF‐κB) activation were assessed using an enzyme‐linked immunosorbent assay (ELISA), northern blotting, and a gel‐mobility shift method, respectively.

Results:  Rgps and FXa activated IL‐6 and MMP‐1 release in human gingival fibroblasts through their amidolytic activities and in mitogen‐activated protein kinase (MAPK) and NF‐κB dependent manners. DX‐9065a inhibited FXa‐induced IL‐6 mRNA expression and NF‐κB activation. DX‐9065a inhibited amidolytic activities of FXa and Rgps in vitro and ex vivo.

Conclusion:  Rgps and FXa are potent inflammatory mediators and DX‐9065a may be a useful therapeutic drug for periodontal disease.
Mouthguard utilization rates during sport activities in Ankara, Turkey
Authors: Çetinbaş Tuğba , Sönmez Hayriye
Published: February 2006

Abstract –  The objective of this study was to determine the attitudes towards mouthguard use in Ankara, Turkey. In the first part of this study, an eight‐item questionnaire was distributed to 22 coaches from 15 secondary schools randomly selected from five municipalities of Ankara, Turkey. The questionnaire sought information on how much coaches know regarding mouthguards and how often children and adolescents of the ages 11–18 use mouthguards. The second part of the study was based on the data obtained from direct interviews answered by 121 university athletes of three different sport modalities (football, ice hockey and martial arts). The purpose of this part of the study was to determine the rate of mouthguard use and the frequency and type of oral trauma in these athletes. The result of the coaches’ questionnaires revealed that; none of the 11–18 years old children and adolescents used mouthguards while participating in sports. Of the coaches, 77.2% had seen orofacial trauma in this age group during sport activities and 95.5% of the coaches believed that mouthguards prevented oral injuries. Of the coaches, 72.7% reported that children and adolescents should use mouthguards in sport activities. The second part of the study showed that although all of the athletes owned mouth‐formed type of mouthguards, the utilization rate was 74.4%. Of all players, 13.2% had suffered from one or more form of oral injury while not wearing mouthguards. The results show that in Turkey, the use of mouthguards has not become widespread in sports. It can be concluded that regular mouthguard use in sports should be encouraged in Turkey.
Magnetic Resonance Imaging of the Knee: a Review
Authors: Vincken P. W. J. , ter Braak B. P. M. , van Erkel A. R. , Coerkamp E. G. , de Rooy T. P. W. , Mallens W. M. C. , Bloem J. L.
Published: February 2006

In the past 15 years, magnetic resonance imaging (MRI) of the knee has become available as an alternative to diagnostic arthroscopy. MRI has proven to be accurate for the diagnosis of intra‐ and peri‐articular pathology, especially for meniscal pathology (accounting for 86% of the indications for arthroscopy) and ligamentous injuries. It is good enough, especially when using the concept of composite injury (sensitivity of 87.3% and specificity of 88.4%), to appropriately identify patients, who require arthroscopic therapy. In playing this role MRI has diagnostic and therapeutic impact. MRI, when used in all patients with high clinical suspicion of intra‐articular knee pathology instead of direct arthroscopy, can avoid 35% of arthroscopies. By influencing the therapy received by a patient, MRI also has the ability to influence patient outcome and societal costs. In patients with sub‐acute and chronic knee complaints and with high clinical suspicion of intra‐articular knee pathology MRI of the knee can be used to select patients for arthroscopy without additional societal costs and without disadvantageous effect on patient outcome.
Derangement of Knee: Role of Radionuclide Imaging in the Diagnosis
Authors: Prasad V. R.
Published: February 2006

Bone scintigraphy in diagnosis of knee derangements is a very useful investigation. From its inception, bone scintigram has developed into a reliable tool with advancing technologies of both hardware and software. The bone scintigraphy is not widely performed though it can be very rewarding especially in diagnosing knee lesions. Bone scintigraphy and magnetic resonance imaging (MRI) are complementary in diagnosing the lesions and where MRI is contra‐indicated, bone scintigram has established itself as an alternative.
Physician Shopping in Workers' Compensation: Evidence from California
Authors: Seabury Seth A. , Reville Robert T. , Neuhauser Frank
Published: February 2006

Physician evaluations of impairment severity have a significant impact on the size of permanent disability benefits awarded to injured workers in workers' compensation. This gives both parties in a disputed claim the incentive to “shop” for physicians who will provide them with sympathetic evaluations. In this article we use data from the California workers' compensation system on competing physician evaluations for the same injury to study the extent to which the ability to select a physician results in a more favorable disability rating. We find that disability ratings based on evaluations from physicians selected by the applicant are 23 percent higher than those based on a neutral evaluation, while ratings based on a defense physician's evaluation tend to be about 5 percent lower. Moreover, we match these data to earnings loss data and estimate the extent to which applicant, defense, or neutral ratings best predict the outcomes of injured workers. The neutral ratings appear to do the best job of predicting earnings losses overall, though not by a substantial margin.
Case Characteristics and Defendant Tenant Default in a Housing Court
Authors: Larson Erik
Published: February 2006

Although frequently cited as an important influence on case outcomes, defendant default in lower courts is not sufficiently studied as an outcome in its own right. In this article, I develop theoretical propositions and hypotheses concerning the impact of case characteristics on tenant defendant default and examine these hypotheses in light of data on 677 cases in a housing court. I find that allegations that are easier to dispute (those concerning a breach of lease, rather than nonpayment of rent) and higher monthly rent levels are associated with lower levels of default. Additionally, tenant default rates are highest in areas with the highest concentration of poverty. These findings reveal the importance of considering case characteristics in studies of legal participation and as a basis for organizational reform.
Inhibition of polyamine and spermine oxidases by polyamine analogues
Authors: Bianchi Marzia , Polticelli Fabio , Ascenzi Paolo , Botta Maurizio , Federico Rodolfo , Mariottini Paolo , Cona Alessandra
Published: February 2006

Polyamine oxidase (PAO) and spermine oxidase (SMO) are involved in the catabolism of polyamines – basic regulators of cell growth and proliferation. The discovery of selective inhibitors of PAO and SMO represents an important tool in studying the involvement of these enzymes in polyamine homeostasis and a starting point for the development of novel antineoplastic drugs. Here, a comparative study on murine PAO (mPAO) and SMO (mSMO) inhibition by the polyamine analogues 1,8‐diaminooctane, 1,12‐diaminododecane, N‐prenylagmatine (G3), guazatine and N,N1‐bis(2,3‐butadienyl)‐1,4‐butanediamine (MDL72527) is reported. Interestingly, 1,12‐Diaminododecane and G3 behave as specific inhibitors of mPAO, values of Ki for mPAO inhibition being lower than those for mSMO inactivation by several orders of magnitude. The analysis of molecular models of mPAO and mSMO indicates a significant reduction of the hydrophobic pocket located in maize PAO (MPAO) at the wider catalytic tunnel opening. This observation provides a rationale to explain the lower affinity displayed by G3, guazatine and MDL72527 for mPAO and mSMO as compared to MPAO. The different behaviour displayed by 1,12‐diaminododecane towards mPAO and mSMO reveals the occurrence of basic differences in the ligand binding mode of the two enzymes, the first enzyme interacting mainly with substrate secondary amino groups and the second one with substrate primary amino groups. Thus, the data reported here provide the basis for the development of novel and selective inhibitors able to discriminate between mammalian SMO and PAO activities.
Coiled–coil interactions modulate multimerization, mitochondrial binding and kinase activity of myotonic dystrophy protein kinase splice isoforms
Authors: van Herpen René E. M. A. , Tjeertes Jorrit V. , Mulders Susan A. M. , Ophuis Ralph J. A. Oude , Wieringa Bé , Wansink Derick G.
Published: February 2006

The myotonic dystrophy protein kinase polypeptide repertoire in mice and humans consists of six different splice isoforms that vary in the nature of their C‐terminal tails and in the presence or absence of an internal Val–Ser–Gly–Gly–Gly motif. Here, we demonstrate that myotonic dystrophy protein kinase isoforms exist in high‐molecular‐weight complexes controlled by homo‐ and heteromultimerization. This multimerization is mediated by coiled–coil interactions in the tail‐proximal domain and occurs independently of alternatively spliced protein segments or myotonic dystrophy protein kinase activity. Complex formation was impaired in myotonic dystrophy protein kinase mutants in which three leucines at positions a and d in the coiled‐coil heptad repeats were mutated to glycines. These coiled‐coil mutants were still capable of autophosphorylation and transphosphorylation of peptides, but the rates of their kinase activities were significantly lowered. Moreover, phosphorylation of the natural myotonic dystrophy protein kinase substrate, myosin phosphatase targeting subunit, was preserved, even though binding of the myotonic dystrophy protein kinase to the myosin phosphatase targeting subunit was strongly reduced. Furthermore, the association of myotonic dystrophy protein kinase isoform C to the mitochondrial outer membrane was weakened when the coiled–coil interaction was perturbed. Our findings indicate that the coiled‐coil domain modulates myotonic dystrophy protein kinase multimerization, substrate binding, kinase activity and subcellular localization characteristics.