bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial and temporal distribution of the malaria mosquito Anopheles arabiensis in northern Sudan: influence of environmental factors and implications for vector control
Authors: Ageep Tellal B , Cox Jonathan , Hassan M'oawia M , Knols Bart GJ , Benedict Mark Q , Malcolm Colin A , Babiker Ahmed , El Sayed Badria B 
Published: June 2009

Abstract

Background
Malaria is an important public health problem in northern Sudan, but little is known about the dynamics of its transmission. Given the characteristic low densities of Anopheles arabiensis and the difficult terrain in this area, future vector control strategies are likely to be based on area-wide integrated pest management (AW-IPM) that may include the sterile insect technique (SIT). To support the planning and implementation of future AW-IPM activities, larval surveys were carried out to provide key data on spatial and seasonal dynamics of local vector populations.

Methods
Monthly cross-sectional larval surveys were carried out between March 2005 and May 2007 in two localities (Dongola and Merowe) adjacent to the river Nile. A stratified random sampling strategy based on the use of Remote Sensing (RS), Geographical Information Systems (GIS) and the Global Positioning System (GPS) was used to select survey locations. Breeding sites were mapped using GPS and data on larval density and breeding site characteristics were recorded using handheld computers. Bivariate and multivariate logistic regression models were used to identify breeding site characteristics associated with increased risk of presence of larvae. Seasonal patterns in the proportion of breeding sites positive for larvae were compared visually to contemporaneous data on climate and river height.

Results
Of a total of 3,349 aquatic habitats sampled, 321 (9.6%) contained An. arabiensis larvae. The frequency with which larvae were found varied markedly by habitat type. Although most positive sites were associated with temporary standing water around the margins of the main Nile channel, larvae were also found at brickworks and in areas of leaking pipes and canals – often far from the river. Close to the Nile channel, a distinct seasonal pattern in larval populations was evident and appeared to be linked to the rise and fall of the river level. These patterns were not evident in vector populations breeding in artificial water sources away from the river.

Conclusion
The GIS-based survey strategy developed in this study provides key data on the population dynamics of An. arabiensis in Northern State. Quantitative estimates of the contributions of various habitat types and their proximity to settlements provide a basis for planning a strategy for reducing malaria risk by elimination of the vector population.
An early burst of IFN-γ induced by the pre-erythrocytic stage favours Plasmodium yoelii parasitaemia in B6 mice
Authors: Soulard Valérie , Roland Jacques , Gorgette Olivier , Barbier Eliane , Cazenave Pierre-André , Pied Sylviane 
Published: June 2009

AbstractBackgroundIn murine models of malaria, an early proinflammatory response has been associated with the resolution of blood-stage infection. To dissect the protective immune mechanims that allow the control of parasitaemia, the early immune response of C57BL/6 mice induced during a non-lethal plasmodial infection was analysed.MethodsMice were infected withPlasmodium yoelii265BY sporozoites, the natural invasive form of the parasite, in order to complete its full life cycle. The concentrations of three proinflammatory cytokines in the sera of mice were determined by ELISA at different time points of infection. The contribution of the liver and the spleen to this cytokinic response was evaluated and the cytokine-producing lymphocytes were identified by flow cytometry. The physiological relevance of these results was tested by monitoring parasitaemia in genetically deficient C57BL/6 mice or wild-type mice treated with anti-cytokine neutralizing antibody. Finally, the cytokinic response in sera of mice infected with parasitized-RBCs was analysed.ResultsThe early immune response of C57BL/6 mice to sporozoite-induced malaria is characterized by a peak of IFN-γ in the serum at day 5 of infection and splenic CD4 T lymphocytes are the major producer of this cytokine at this time point. Somewhat unexpected, the parasitaemia is significantly lower inP. yoelii-infected mice in the absence of IFN-γ. More precisely, at early time points of infection, IFN-γ favours parasitaemia, whereas helping to clear efficiently the blood-stage parasites at later time points. Interestingly, the early IFN-γ burst is induced by the pre-erythrocytic stage.ConclusionThese results challenge the current view regarding the role of IFN-γ on the control of parasite growth since they show that IFN-γ is not an essential mediator of protection inP. yoelii-infected C57BL/6 mice. Moreover, the mice parasitaemia is more efficiently controlled in the absence of an early IFN-γ production, suggesting that this cytokine promotes parasite's growth. Finally, this early burst of IFN-γ is induced by the pre-erythrocytic stage, showing the impact of this stage on the immune response taking place during the subsequent erythrocytic stage.
Heme oxygenase-1 and its metabolites affect pancreatic tumor growth in vivo
Authors: Nuhn Philipp , Künzli Beat M , Hennig René , Mitkus Tomas , Ramanauskas Tadas , Nobiling Rainer , Meuer Stefan C , Friess Helmut , Berberat Pascal O 
Published: June 2009

Abstract

Background
Pancreatic cancer (PaCa) is a fatal human cancer due to its exceptional resistance to all current anticancer therapies. The cytoprotective enzyme heme oxygenase-1 (HO-1) is significantly overexpressed in PaCa and seems to play an important role in cancer resistance to anticancer treatment. The inhibition of HO-1 sensitized PaCa cells to chemo- and radiotherapy in vitro.
Therefore, we investigated the effects of HO-1 and its metabolites biliverdin, carbon monoxide and iron on PaCa cells.
PaCa cell lines with divergent HO-1 expression patterns were used in a murine orthotopic cancer model. HO-1 expression and activity was regulated by zinc (inhibition) and cobalt (induction) protoporphyrin. Furthermore, the influence of cellular HO-1 levels and its metabolites on effects of standard chemotherapy with gemcitabine was tested in vivo and in vitro.

Results
High HO-1 expression in PaCa cell lines was associated with increased chemoresistance in vitro. Chemoresistance to gemcitabine was increased during HO-1 induction in PaCa cells expressing low levels of HO-1. The inhibition of HO-1 activity in pancreatic tumors with high HO-1 boosted chemotherapeutic effects in vivo significantly. Furthermore, biliverdin and iron promoted PaCa resistance to chemotherapy. Consequently, specific iron chelation by desferrioxamine revealed profound anticancerous effects.

Conclusion
In summary, the inhibition of HO-1 and the chelation of iron in PaCa cells were associated with increased sensitivity and susceptibility of pancreatic tumors to chemotherapy in vivo. The metabolites biliverdin and iron seem to be involved in HO-1-mediated resistance to anticancer treatment. Therefore, HO-1 inhibition or direct interference with its metabolites may evolve new PaCa treatment strategies.
Surgical treatment for locally advanced lower third rectal cancer after neoadjuvent chemoradiation with capecitabine: prospective phase II trial
Authors: Elwanis Mostafa Abd , Maximous Doaa W. , Elsayed Mohamed Ibrahim , Mikhail Nabiel N. H. 
Published: June 2009

Abstract

Introduction
Treatment of rectal cancer requires a multidisciplinary approach with standardized surgical, pathological and radiotherapeutic procedures. Sphincter preserving surgery for cancer of the lower rectum needs a long-course of neoadjuvant treatments to reduce tumor volume, to induce down-staging that increases circumferential resection margin, and to facilitate surgery.

Aim
To evaluate the rate of anal sphincter preservation in low lying, resectable, locally advanced rectal cancer and the resectability rate in unresectable cases after neoadjuvent chemoradiation by oral Capecitabine.

Patients and methods
This trial included 43 patients with low lying (4–7 cm from anal verge) locally advanced rectal cancer, of which 33 were resectable. All patients received preoperative concurrent chemoradiation (45 Gy/25 fractions over 5 weeks with oral capecitabine 825 mg/m2 twice daily on radiotherapy days), followed after 4–6 weeks by total mesorectal excision technique.

Results
Preoperative chemoradiation resulted in a complete pathologic response in 4 patients (9.3%; 95% CI 3–23.1) and an overall downstaging in 32 patients (74.4%; 95% CI 58.5–85). Sphincter sparing surgical procedures were done in 20 out of 43 patients (46.5%; 95% CI 31.5–62.2). The majority (75%) were of clinical T3 disease. Toxicity was moderate and required no treatment interruption. Grade II anemia occurred in 4 patients (9.3%, 95% CI 3–23.1), leucopenia in 2 patients (4.7%, 95% CI 0.8–17) and radiation dermatitis in 4 patients (9.3%, 95% CI 3–23.1) respectively.

Conclusion
In patients with low lying, locally advanced rectal cancer, preoperative chemoradiation using oral capecitabine 825 mg/m2, twice a day on radiotherapy days, was tolerable and effective in downstaging and resulted in 46.5% anal sphincter preservation rate.
In vivo properties of the proangiogenic peptide QK
Authors: Santulli Gaetano , Ciccarelli Michele , Palumbo Gianluigi , Campanile Alfonso , Galasso Gennaro , Ziaco Barbara , Altobelli Giovanna Giuseppina , Cimini Vincenzo , Piscione Federico , D'Andrea Luca Domenico , Pedone Carlo , Trimarco Bruno , Iaccarino Guido 
Published: June 2009

Abstract
The main regulator of neovascularization is Vascular Endothelial Growth Factor (VEGF). We recently demonstrated that QK, a de novo engineered VEGF mimicking peptide, shares in vitro the same biological properties of VEGF, inducing capillary formation and organization. On these grounds, the aim of this study is to evaluate in vivo the effects of this small peptide. Therefore, on Wistar Kyoto rats, we evaluated vasomotor responses to VEGF and QK in common carotid rings. Also, we assessed the effects of QK in three different models of angiogenesis: ischemic hindlimb, wound healing and Matrigel plugs. QK and VEGF present similar endothelium-dependent vasodilatation. Moreover, the ability of QK to induce neovascularization was confirmed us by digital angiographies, dyed beads dilution and histological analysis in the ischemic hindlimb as well as by histology in wounds and Matrigel plugs. Our findings show the proangiogenic properties of QK, suggesting that also in vivo this peptide resembles the full VEGF protein. These data open to new fields of investigation on the mechanisms of activation of VEGF receptors, offering clinical implications for treatment of pathophysiological conditions such as chronic ischemia.
The mathematics of tanning
Authors: Thingnes Josef , Øyehaug Leiv , Hovig Eivind , Omholt Stig W 
Published: June 2009

AbstractBackgroundThe pigment melanin is produced by specialized cells, called melanocytes. In healthy skin, melanocytes are sparsely spread among the other cell types in the basal layer of the epidermis. Sun tanning results from an UV-induced increase in the release of melanin to neighbouring keratinocytes, the major cell type component of the epidermis as well as redistribution of melanin among these cells. Here we provide a mathematical conceptualization of our current knowledge of the tanning response, in terms of a dynamic model. The resolution level of the model is tuned to available data, and its primary focus is to describe the tanning response following UV exposure.ResultsThe model appears capable of accounting for available experimental data on the tanning response in different skin and photo types. It predicts that the thickness of the epidermal layer and how far the melanocyte dendrites grow out in the epidermal layers after UV exposure influence the tanning response substantially.ConclusionDespite the paucity of experimental validation data the model is constrained enough to serve as a foundation for the establishment of a theoretical-experimental research programme aimed at elucidating the more fine-grained regulatory anatomy underlying the tanning response.
Yield-determining factors in high-solids enzymatic hydrolysis of lignocellulose
Authors: Kristensen Jan B , Felby Claus , Jørgensen Henning 
Published: June 2009

AbstractBackgroundWorking at high solids (substrate) concentrations is advantageous in enzymatic conversion of lignocellulosic biomass as it increases product concentrations and plant productivity while lowering energy and water input. However, for a number of lignocellulosic substrates it has been shown that at increasing substrate concentration, the corresponding yield decreases in a fashion which can not be explained by current models and knowledge of enzyme-substrate interactions. This decrease in yield is undesirable as it offsets the advantages of working at high solids levels. The cause of the 'solids effect' has so far remained unknown.ResultsThe decreasing conversion at increasing solids concentrations was found to be a generic or intrinsic effect, describing a linear correlation from 5 to 30% initial total solids content (w/w). Insufficient mixing has previously been shown not to be involved in the effect. Hydrolysis experiments with filter paper showed that neither lignin content nor hemicellulose-derived inhibitors appear to be responsible for the decrease in yields. Product inhibition by glucose and in particular cellobiose (and ethanol in simultaneous saccharification and fermentation) at the increased concentrations at high solids loading plays a role but could not completely account for the decreasing conversion. Adsorption of cellulases was found to decrease at increasing solids concentrations. There was a strong correlation between the decreasing adsorption and conversion, indicating that the inhibition of cellulase adsorption to cellulose is causing the decrease in yield.ConclusionInhibition of enzyme adsorption by hydrolysis products appear to be the main cause of the decreasing yields at increasing substrate concentrations in the enzymatic decomposition of cellulosic biomass. In order to facilitate high conversions at high solids concentrations, understanding of the mechanisms involved in high-solids product inhibition and adsorption inhibition must be improved.
Integrated analysis of DNA methylation and gene expression reveals specific signaling pathways associated with platinum resistance in ovarian cancer
Authors: Li Meng , Balch Curt , Montgomery John S , Jeong Mikyoung , Chung Jae Hoon , Yan Pearlly , Huang Tim HM , Kim Sun , Nephew Kenneth P 
Published: June 2009

Abstract

Background
Cisplatin and carboplatin are the primary first-line therapies for the treatment of ovarian cancer. However, resistance to these platinum-based drugs occurs in the large majority of initially responsive tumors, resulting in fully chemoresistant, fatal disease. Although the precise mechanism(s) underlying the development of platinum resistance in late-stage ovarian cancer patients currently remains unknown, CpG-island (CGI) methylation, a phenomenon strongly associated with aberrant gene silencing and ovarian tumorigenesis, may contribute to this devastating condition.

Methods
To model the onset of drug resistance, and investigate DNA methylation and gene expression alterations associated with platinum resistance, we treated clonally derived, drug-sensitive A2780 epithelial ovarian cancer cells with increasing concentrations of cisplatin. After several cycles of drug selection, the isogenic drug-sensitive and -resistant pairs were subjected to global CGI methylation and mRNA expression microarray analyses. To identify chemoresistance-associated, biological pathways likely impacted by DNA methylation, promoter CGI methylation and mRNA expression profiles were integrated and subjected to pathway enrichment analysis.

Results
Promoter CGI methylation revealed a positive association (Spearman correlation of 0.99) between the total number of hypermethylated CGIs and GI50 values (i.e., increased drug resistance) following successive cisplatin treatment cycles. In accord with that result, chemoresistance was reversible by DNA methylation inhibitors. Pathway enrichment analysis revealed hypermethylation-mediated repression of cell adhesion and tight junction pathways and hypomethylation-mediated activation of the cell growth-promoting pathways PI3K/Akt, TGF-beta, and cell cycle progression, which may contribute to the onset of chemoresistance in ovarian cancer cells.

Conclusion
Selective epigenetic disruption of distinct biological pathways was observed during development of platinum resistance in ovarian cancer. Integrated analysis of DNA methylation and gene expression may allow for the identification of new therapeutic targets and/or biomarkers prognostic of disease response. Finally, our results suggest that epigenetic therapies may facilitate the prevention or reversal of transcriptional repression responsible for chemoresistance and the restoration of sensitivity to platinum-based chemotherapeutics.
Fractionated irradiation induced radio-resistant esophageal cancer EC109 cells seem to be more sensitive to chemotherapeutic drugs
Authors: Xie Li , Song Xianrang , Yu Jinming , Wei Ling , Song Bao , Wang Xingwu , Lv Liyan 
Published: June 2009

Abstract

Background
Chemo-radiotherapy, a combination of chemotherapy and radiotherapy, is the most frequent treatment for patients with esophageal cancer. In the process of radiotherapy, the radiosensitive cancer will become a radio-resistant one.

Methods
In order to detect the chemotherapeutic drug sensitivity in radio-resistant cancer cells and improve the therapy efficiency, we firstly established a radio-resistant esophageal cancer cell model (referred to as EC109/R) from the human esophageal squamous cell carcinoma cell line EC109 through fractionated irradiation using X-rays. The radio-sensitivity of EC109/R cells was measured by clonogenic assay. To detect the drug sensitivity for EC109/R compared to its parent cells, we employed MTT method to screen the effectiveness of five different drugs commonly used in clinical therapy. The ratio of apoptosis was examined by flow cytometry.

Results
EC109/R cells were more sensitive to 5-fluorouracil, doxorubicin, paclitaxel and etoposide, but tolerant to cisplatin compared to its original cells.

Conclusion
Our study implies that fractionated irradiation induced radio-resistant esophageal cancer cell is more sensitive to certain kind of chemotherapeutic drugs. It provides evidence for choosing the sequence of radiotherapy and chemotherapy in esophageal cancer.
Predictors of Primary Imatinib Resistance in Chronic Myelogenous Leukemia Are Distinct From Those in Secondary Imatinib Resistance
Authors: Zhang Wenyong W. , Cortes Jorge E. , Yao Hui , Zhang Li , Reddy Neelima G. , Jabbour Elias , Kantarjian Hagop M. , Jones Dan 
Published: June 2009

Purpose A subset of patients with chronic myelogenous leukemia (CML) do not respond to the tyrosine kinase inhibitor (TKI) imatinib mesylate. Such primary imatinib resistance is distinguished from secondary resistance which reemerges after attainment of cytogenetic remission. Patients and Methods We studied gene expression patterns in total WBCs using a panel of 21 genes previously implicated in TKI handling, resistance, or progression comparing patients who had newly diagnosed TKI-naive CML that had optimal (n = 41), or suboptimal (n = 7) responses to imatinib, or primary resistance (n = 20). Expression patterns were compared to those in secondary TKI-resistant chronic phase CML without ABL1 kinase domain mutations (n = 29), and to lymphoid (n = 15) or myeloid blast phase disease (n = 12). Results Fifteen genes in the panel distinguished blast phase from chronic phase disease, and 12 genes distinguished newly diagnosed CML from TKI-resistant CML without ABL1 kinase domain mutations, but only a single gene, prostaglandin-endoperoxide synthase 1/cyclooxgenase 1 (PTGS1/COX1; P = .005), differentiated imatinib-responsive from primary imatinib-resistant CML. The association of primary imatinib resistance with higher transcript levels of the drug metabolism gene PTGS1 was confirmed in a separate data set of 68 newly diagnosed, imatinib-treated CML (P = .008). In contrast, up to 11 different genes were identified in a multivariate model that optimally discriminated secondary imatinib resistance lacking ABL1 kinase domain mutation from imatinib-responsive cases, likely related to the more complex pathogenesis of secondary resistance. Conclusion Gene expression profiling of CML at diagnosis for PTGS1 may be useful in predicting imatinib response and in selecting alternate therapy.
Pretreatment Prostate-Specific Antigen (PSA) Velocity and Doubling Time Are Associated With Outcome but Neither Improves Prediction of Outcome Beyond Pretreatment PSA Alone in Patients Treated With Radical Prostatectomy
Authors: O'Brien Matthew Frank , Cronin Angel M. , Fearn Paul A. , Smith Brandon , Stasi Jason , Guillonneau Bertrand , Scardino Peter T. , Eastham James A. , Vickers Andrew J. , Lilja Hans 
Published: June 2009

Purpose Controversy exists as to whether current pretreatment prostate-specific antigen (PSA) dynamics enhance outcome prediction in patients undergoing treatment for prostate cancer. We assessed whether pretreatment PSA velocity (PSAV) or doubling time (PSADT) predicted outcome in men undergoing radical prostatectomy and whether any definition enhanced accuracy of an outcome prediction model. Patients and Methods The cohort included 2,938 patients with two or more PSA values before radical prostatectomy. Biochemical recurrence (BCR) occurred in 384 patients, and metastases occurred in 63 patients. Median follow-up for patients without BCR was 2.1 years. We used univariate Cox proportional hazards regression to evaluate associations between published definitions of PSADT and PSAV with BCR and metastasis. Predictive accuracy was assessed using the concordance index. Results On univariate analysis, two of 12 PSADT and four of 10 PSAV definitions were univariately associated with both BCR and metastasis (P < .05). One PSADT and one PSAV definition had a higher predictive accuracy for BCR over PSA alone, and four PSAV definitions improved prediction of metastasis. However, the improvements in predictive accuracy were small, associated with wide CIs, and markedly reduced if additional predictors of stage and grade were included alongside PSA. Modeling with random variables suggests that similar results would be expected by chance. Conclusion We found no clear evidence that any definition of PSA dynamics substantially enhances the predictive accuracy of a single pretreatment PSA alone.