138 research outputs found
Identification of biomarkers for the antiangiogenic and antitumour activity of the superoxide dismutase 1 (SOD1) inhibitor tetrathiomolybdate (ATN-224)
Tetrathiomolybdate (choline salt; ATN-224), a specific, high-affinity copper binder, is currently being evaluated in several phase II cancer trials. ATN-224 inhibits CuZn superoxide dismutase 1 (SOD1) leading to antiangiogenic and antitumour effects. The pharmacodynamics of tetrathiomolybdate has been followed by tracking ceruloplasmin (Cp), a biomarker for systemic copper. However, at least in mice, the inhibition of angiogenesis occurs before a measurable decrease in systemic copper is observed. Thus, the identification and characterisation of other biomarkers to follow the activity of ATN-224 in the clinic is of great interest. Here, we present the preclinical evaluation of two potential biomarkers for the activity of ATN-224: (i) SOD activity measurements in blood cells in mice and (ii) levels of endothelial progenitor cells (EPCs) in bonnet macaques treated with ATN-224. The superoxide dismutase activity in blood cells in mice is rapidly inhibited by ATN-224 treatment at doses at which angiogenesis is maximally inhibited. Furthermore, ATN-224 dosing in bonnet macaques causes a profound and reversible decrease in EPCs without significant toxicity. Thus, both SOD activity measurements and levels of EPCs may be useful biomarkers of the antiangiogenic activity of ATN-224 to be used in its clinical development
HIV-1 competition experiments in humanized mice show that APOBEC3H imposes selective pressure and promotes virus adaptation
APOBEC3 (A3) family proteins are DNA cytosine deaminases recognized for contributing to
HIV-1 restriction and mutation. Prior studies have demonstrated that A3D, A3F, and A3G
enzymes elicit a robust anti-HIV-1 effect in cell cultures and in humanized mouse models.
Human A3H is polymorphic and can be categorized into three phenotypes: stable, intermediate,
and unstable. However, the anti-viral effect of endogenous A3H in vivo has yet to be
examined. Here we utilize a hematopoietic stem cell-transplanted humanized mouse model
and demonstrate that stable A3H robustly affects HIV-1 fitness in vivo. In contrast, the selection
pressure mediated by intermediate A3H is relaxed. Intriguingly, viral genomic RNA
sequencing reveled that HIV-1 frequently adapts to better counteract stable A3H during replication
in humanized mice. Molecular phylogenetic analyses and mathematical modeling
suggest that stable A3H may be a critical factor in human-to-human viral transmission.
Taken together, this study provides evidence that stable variants of A3H impose selective
pressure on HIV-1
Stimulation of lymphocyte anti-melanoma activity by co-cultured macrophages activated by complex homeopathic medication
<p>Abstract</p> <p>Background</p> <p>Melanoma is the most aggressive form of skin cancer, and the most rapidly expanding cancer in terms of worldwide incidence. Chemotherapeutic approaches to treat melanoma have been uniformly disappointing. A Brazilian complex homeopathic medication (CHM), used as an immune modulator, has been recommended for patients with depressed immune systems. Previous studies in mice have demonstrated that the CHM activates macrophages, induces an increase in the number of leukocytes and improves the murine response against Sarcoma-180.</p> <p>Methods</p> <p>Here we studied the interaction of mouse lymph node lymphocytes, co-cultured <it>in vitro </it>with macrophages in the presence or absence of the CHM, with B16F10 melanoma cells.</p> <p>Results</p> <p>Lymphocytes co-cultured with macrophages in the presence of the CHM had greater anti-melanoma activity, reducing melanoma cell density and increasing the number of lysed tumor cells. There was also a higher proportion of activated (CD25<sup>+</sup>) lymphocytes with increased viability. Overall, lymphocytes activated by treatment destroyed growing cancer cells more effectively than control lymphocytes.</p> <p>Conclusion</p> <p>Co-culture of macrophages with lymphocytes in the presence of the CHM enhanced the anti-cancer performance of lymphocytes against a very aggressive lineage of melanoma cells. These results suggest that non-toxic therapies using CHMs are a promising alternative approach to the treatment of melanomas. In addition, they are attractive combination-therapy candidates, which may enhance the efficacy of conventional medicines by improving the immune response against tumor cells.</p
High-Precision, Whole-Genome Sequencing of Laboratory Strains Facilitates Genetic Studies
Whole-genome sequencing is a powerful technique for obtaining the reference sequence information of multiple organisms. Its use can be dramatically expanded to rapidly identify genomic variations, which can be linked with phenotypes to obtain biological insights. We explored these potential applications using the emerging next-generation sequencing platform Solexa Genome Analyzer, and the well-characterized model bacterium Bacillus subtilis. Combining sequencing with experimental verification, we first improved the accuracy of the published sequence of the B. subtilis reference strain 168, then obtained sequences of multiple related laboratory strains and different isolates of each strain. This provides a framework for comparing the divergence between different laboratory strains and between their individual isolates. We also demonstrated the power of Solexa sequencing by using its results to predict a defect in the citrate signal transduction pathway of a common laboratory strain, which we verified experimentally. Finally, we examined the molecular nature of spontaneously generated mutations that suppress the growth defect caused by deletion of the stringent response mediator relA. Using whole-genome sequencing, we rapidly mapped these suppressor mutations to two small homologs of relA. Interestingly, stable suppressor strains had mutations in both genes, with each mutation alone partially relieving the relA growth defect. This supports an intriguing three-locus interaction module that is not easily identifiable through traditional suppressor mapping. We conclude that whole-genome sequencing can drastically accelerate the identification of suppressor mutations and complex genetic interactions, and it can be applied as a standard tool to investigate the genetic traits of model organisms
Maximization of propylene in an industrial FCC unit
YesThe FCC riser cracks gas oil into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. The production objective of the riser is usually the maximization of gasoline and diesel, but it can also be to maximize propylene. The optimization and parameter estimation of a six-lumped catalytic cracking reaction of gas oil in FCC is carried out to maximize the yield of propylene using an optimisation framework developed in gPROMS software 5.0 by optimizing mass flow rates and temperatures of catalyst and gas oil. The optimal values of 290.8 kg/s mass flow rate of catalyst and 53.4 kg/s mass flow rate of gas oil were obtained as propylene yield is maximized to give 8.95 wt%. When compared with the base case simulation value of 4.59 wt% propylene yield, the maximized propylene yield is increased by 95%
Obesity is associated with insulin resistance and components of the metabolic syndrome in Lebanese adolescents
adolescents has been reported to range between 18–42%, depending on country of origin, thus suggesting an ethnicbased association between obesity and MS. Aim: This study aims to investigate the magnitude of the association between obesity, insulin resistance and components of MS among adolescents in Lebanon. Subjects and methods: The sample included 263 adolescents at 4 th and 5 th Tanner stages of puberty (104 obese; 78 overweight; 81 normal weight). Anthropometric, biochemical and blood pressure measurements were performed. Body fat was assessed using dual-energy X-ray absorptiometry. Results: According to International Diabetes Federation criteria, MS was identified in 21.2 % of obese, 3.8 % of overweight and 1.2 % of normal weight subjects. The most common metabolic abnormalities among subjects having MS were elevated waist circumference (96.2%), low HDL (96.2%) and hypertriglyceridemia (73.1%). Insulin resistance was identified in all subjects having MS. Regression analyses showed that percentage body fat, waist circumference and BMI were similar in their ability to predict the MS in this age group. Conclusions: MSwas identified in asubstantial proportion of Lebanese obese adolescents, thus highlighting the importance of early screening for obesity-associated metabolic abnormalities and of developing successful multi-component interventions addressing adolescent obesity
Incidence of cancer in children residing in ten jurisdictions of the Mexican Republic: importance of the Cancer registry (a population-based study)
BACKGROUND: In 1996, Mexico started to register cases of childhood cancer. Here, we describe the incidence of cancer in children, residing in ten Mexican jurisdictions, who were treated by the Instituto Mexicano del Seguro Social (IMSS). METHODS: New cases of childhood cancer, which were registered prospectively in nine principal Medical Centers of IMSS during the periods 1998–2000 (five jurisdictions) and 1996–2002 (five jurisdictions), were analyzed. Personnel were specifically trained to register, capture, and encode information. For each of these jurisdictions, the frequency, average annual age-standardized incidence (AAS) and average annual incidence per period by sex and, age, were calculated (rates per 1,000,000 children/years). RESULTS: In total 2,615 new cases of cancer were registered, with the male/female ratio generally >1, but in some tumors there were more cases in females (retinoblastoma, germ cells tumors). The principal groups of neoplasms in seven jurisdictions were leukemias, central nervous system tumors (CNS tumors), and lymphomas, and the combined frequency for these three groups was 62.6 to 77.2%. Most frequently found (five jurisdictions) was the North American-European pattern (leukemias-CNS tumors-lymphomas). Eight jurisdictions had AAS within the range reported in the world literature. The highest incidence was found for children underless than five year of age. In eight jurisdictions, leukemia had high incidence (>50). The AAS of lymphomas was between 1.9 to 28.6. Chiapas and Guerrero had the highest AAS of CNS tumors (31.9 and 30.3, respectively). The frequency and incidence of neuroblastoma was low. Chiapas had the highest incidence of retinoblastoma (21.8). Germ-cell tumors had high incidence. CONCLUSION: The North American-European pattern of cancers was the principal one found; the overall incidence was within the range reported worldwide. In general but particularly in two jurisdictions (Yucatán and Chiapas), it will be necessary to carry out studies concerning the causes of cancer in children. Due to the little that is known about the incidence of cancer in Mexican children, it will be necessary to develop a national program to establish a cancer registry for the whole of the country
The role of the small intestine in the development of dietary fat-induced obesity and insulin resistance in C57BL/6J mice
<p>Abstract</p> <p>Background</p> <p>Obesity and insulin resistance are two major risk factors underlying the metabolic syndrome. The development of these metabolic disorders is frequently studied, but mainly in liver, skeletal muscle, and adipose tissue. To gain more insight in the role of the small intestine in development of obesity and insulin resistance, dietary fat-induced differential gene expression was determined along the longitudinal axis of small intestines of C57BL/6J mice.</p> <p>Methods</p> <p>Male C57BL/6J mice were fed a low-fat or a high-fat diet that mimicked the fatty acid composition of a Western-style human diet. After 2, 4 and 8 weeks of diet intervention small intestines were isolated and divided in three equal parts. Differential gene expression was determined in mucosal scrapings using Mouse genome 430 2.0 arrays.</p> <p>Results</p> <p>The high-fat diet significantly increased body weight and decreased oral glucose tolerance, indicating insulin resistance. Microarray analysis showed that dietary fat had the most pronounced effect on differential gene expression in the middle part of the small intestine. By overrepresentation analysis we found that the most modulated biological processes on a high-fat diet were related to lipid metabolism, cell cycle and inflammation. Our results further indicated that the nuclear receptors Ppars, Lxrs and Fxr play an important regulatory role in the response of the small intestine to the high-fat diet. Next to these more local dietary fat effects, a secretome analysis revealed differential gene expression of secreted proteins, such as Il18, Fgf15, Mif, Igfbp3 and Angptl4. Finally, we linked the fat-induced molecular changes in the small intestine to development of obesity and insulin resistance.</p> <p>Conclusion</p> <p>During dietary fat-induced development of obesity and insulin resistance, we found substantial changes in gene expression in the small intestine, indicating modulations of biological processes, especially related to lipid metabolism. Moreover, we found differential expression of potential signaling molecules that can provoke systemic effects in peripheral organs by influencing their metabolic homeostasis. Many of these fat-modulated genes could be linked to obesity and/or insulin resistance. Together, our data provided various leads for a causal role of the small intestine in the etiology of obesity and/or insulin resistance.</p
Association of HIV infection with distribution and viral load of HPV types in Kenya: a survey with 820 female sex workers
<p>Abstract</p> <p>Background</p> <p>Human papillomavirus (HPV) and HIV are each responsible for a considerable burden of disease. Interactions between these infections pose substantial public health challenges, especially where HIV prevalence is high and HPV vaccine coverage low.</p> <p>Methods</p> <p>Between July 2005 and January 2006, a cross-sectional community-based survey in Mombasa, Kenya, enrolled female sex workers using snowball sampling. After interview and a gynaecological examination, blood and cervical cytology samples were taken. Quantitative real-time PCR detected HPV types and viral load measures. Prevalence of high-risk HPV was compared between HIV-infected and -uninfected women, and in women with abnormal cervical cytology, measured using conventional Pap smears.</p> <p>Results</p> <p>Median age of the 820 participants was 28 years (inter-quartile range [IQR] = 24-36 years). One third of women were HIV infected (283/803; 35.2%) and these women were y more likely to have abnormal cervical cytology than HIV-negative women (27%, 73/269, versus 8%, 42/503; <it>P </it>< 0.001). Of HIV-infected women, 73.3% had high-risk HPV (200/273) and 35.5% had HPV 16 and/or 18 (97/273). Corresponding figures for HIV-negative women were 45.5% (229/503) and 15.7% (79/503). After adjusting for age, number of children and condom use, high-risk HPV was 3.6 fold more common in HIV-infected women (95%CI = 2.6-5.1). Prevalence of all 15 of the high-risk HPV types measured was higher among HIV-infected women, between 1.4 and 5.5 fold. Median total HPV viral load was 881 copies/cell in HIV-infected women (IQR = 33-12,110 copies/cell) and 48 copies/cell in HIV-uninfected women (IQR = 6-756 copies/cell; <it>P </it>< 0.001). HPV 16 and/or HPV 18 were identified in 42.7% of LSIL (32/75) and 42.3% of HSIL (11/26) lesions (<it>P </it>= 0.98). High-risk HPV types other than 16 and 18 were common in LSIL (74.7%; 56/75) and HSIL (84.6%; 22/26); even higher among HIV-infected women.</p> <p>Conclusions</p> <p>HIV-infected sex workers had almost four-fold higher prevalence of high-risk HPV, raised viral load and more precancerous lesions. HPV 16 and HPV 18, preventable with current vaccines, were associated with cervical disease, though other high-risk types were commoner. HIV-infected sex workers likely contribute disproportionately to HPV transmission dynamics in the general population. Current efforts to prevent HIV and HPV are inadequate. New interventions are required and improved implementation of existing strategies.</p
An Osteoblast-Derived Proteinase Controls Tumor Cell Survival via TGF-beta Activation in the Bone Microenvironment
Breast to bone metastases frequently induce a "vicious cycle" in which osteoclast mediated bone resorption and proteolysis results in the release of bone matrix sequestered factors that drive tumor growth. While osteoclasts express numerous proteinases, analysis of human breast to bone metastases unexpectedly revealed that bone forming osteoblasts were consistently positive for the proteinase, MMP-2. Given the role of MMP-2 in extracellular matrix degradation and growth factor/cytokine processing, we tested whether osteoblast derived MMP-2 contributed to the vicious cycle of tumor progression in the bone microenvironment.To test our hypothesis, we utilized murine models of the osteolytic tumor-bone microenvironment in immunocompetent wild type and MMP-2 null mice. In longitudinal studies, we found that host MMP-2 significantly contributed to tumor progression in bone by protecting against apoptosis and promoting cancer cell survival (caspase-3; immunohistochemistry). Our data also indicate that host MMP-2 contributes to tumor induced osteolysis (μCT, histomorphometry). Further ex vivo/in vitro experiments with wild type and MMP-2 null osteoclast and osteoblast cultures identified that 1) the absence of MMP-2 did not have a deleterious effect on osteoclast function (cd11B isolation, osteoclast differentiation, transwell migration and dentin resorption assay); and 2) that osteoblast derived MMP-2 promoted tumor survival by regulating the bioavailability of TGFβ, a factor critical for cell-cell communication in the bone (ELISA, immunoblot assay, clonal and soft agar assays).Collectively, these studies identify a novel "mini-vicious cycle" between the osteoblast and metastatic cancer cells that is key for initial tumor survival in the bone microenvironment. In conclusion, the findings of our study suggest that the targeted inhibition of MMP-2 and/or TGFβ would be beneficial for the treatment of bone metastases
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