A Phase II Trial of Pyrazine Diazohydroxide in Patients with Disseminated Malignant Melanoma and no Prior Chemotherapy – Southwest Oncology Group Study

Malignant melanoma is rapidly increasing inthe United States. Metastatic diseaseresponds poorly to currently availablechemotherapy. Pyrazine diazohydroxide(PZDH) is a new agent inhibiting DNAsynthesis that is active in mouse tumormodels and human xenografts and lackscross resistance withmultiple standard agents. In this phase IItrial, patients with no prior chemotherapyor immunotherapyfor metastatic disease and performancestatus (SWOG) of 0–1, were treated withpyrazine diazohydroxide at a dose of 100 mg/m 2 /day by IV bolus injectionover 5–15 minutes for 5 consecutive daysevery 6 weeks. There were 23 eligiblepatients entered on this trial with 74%having PS of 0 and 91% having visceralmetastases. There were no confirmed anti-tumor responses. Theoverall response rate is 0% (95% CI 0%–15%). Median overall survival is sixmonths (95% CI 5-8months). The most common toxicities were hematologic and consisted of lymphopenia,thrombocytopenia, anemia, and leukopenia. Fatigue, and nausea and vomiting were thenext mostcommon toxicities. Pyrazine diazohydroxideby this dose and schedule has insufficientactivity in thetreatment of disseminated malignantmelanoma to warrant further investigation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45216/1/10637_2004_Article_390690.pd

Genetically defined syngeneic mouse models of ovarian cancer as tools for the discovery of combination immunotherapy

Despite advances in immuno-oncology, the relationship between tumor genotypes and response to immunotherapy remains poorly understood, particularly in high-grade serous tubo-ovarian carcinomas (HGSC). We developed a series of mouse models that carry genotypes of human HGSCs and grow in syngeneic immunocompetent hosts to address this gap. We transformed murine-fallopian tube epithelial cells to phenocopy homologous recombination-deficient tumors through a combined loss of p53, Brca1, Pten, Nf1, and overexpression of Myc and p53R172H, which was contrasted to an identical model carrying wild-type Brca1. For homologous recombination-proficient tumors, we constructed genotypes combining loss of p53, and overexpression of Ccne1, Akt2, p53R172H, and driven by KRASG12V or Brd4 or Smarca4 overexpression. These lines form tumors recapitulating human disease, including genotype-driven responses to treatment, and enabled us to identify follistatin as a driver of resistance to checkpoint inhibitors. These data provide proof of concept that our models can identify new immunotherapy targets in HGSC

Triose Phosphate Isomerase Deficiency Is Caused by Altered Dimerization–Not Catalytic Inactivity–of the Mutant Enzymes

Triosephosphate isomerase (TPI) deficiency is an autosomal recessive disorder caused by various mutations in the gene encoding the key glycolytic enzyme TPI. A drastic decrease in TPI activity and an increased level of its substrate, dihydroxyacetone phosphate, have been measured in unpurified cell extracts of affected individuals. These observations allowed concluding that the different mutations in the TPI alleles result in catalytically inactive enzymes. However, despite a high occurrence of TPI null alleles within several human populations, the frequency of this disorder is exceptionally rare. In order to address this apparent discrepancy, we generated a yeast model allowing us to perform comparative in vivo analyses of the enzymatic and functional properties of the different enzyme variants. We discovered that the majority of these variants exhibit no reduced catalytic activity per se. Instead, we observed, the dimerization behavior of TPI is influenced by the particular mutations investigated, and by the use of a potential alternative translation initiation site in the TPI gene. Additionally, we demonstrated that the overexpression of the most frequent TPI variant, Glu104Asp, which displays altered dimerization features, results in diminished endogenous TPI levels in mammalian cells. Thus, our results reveal that enzyme deregulation attributable to aberrant dimerization of TPI, rather than direct catalytic inactivation of the enzyme, underlies the pathogenesis of TPI deficiency. Finally, we discovered that yeast cells expressing a TPI variant exhibiting reduced catalytic activity are more resistant against oxidative stress caused by the thiol-oxidizing reagent diamide. This observed advantage might serve to explain the high allelic frequency of TPI null alleles detected among human populations

Формирование эмоциональной культуры как компонента инновационной культуры студентов

Homozygosity has long been associated with rare, often devastating, Mendelian disorders1 and Darwin was one of the first to recognise that inbreeding reduces evolutionary fitness2. However, the effect of the more distant parental relatedness common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity, ROH), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power3,4. Here we use ROH to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts and find statistically significant associations between summed runs of homozygosity (SROH) and four complex traits: height, forced expiratory lung volume in 1 second (FEV1), general cognitive ability (g) and educational attainment (nominal p<1 × 10−300, 2.1 × 10−6, 2.5 × 10−10, 1.8 × 10−10). In each case increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing convincing evidence for the first time that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples5,6, no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein (LDL) cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection7, this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been

Magnetic polypropylene nanocomposites: Rheological, electrical magnetic and thermal properties

A facile surfactant-free process is introduced to prepare multifunctional polypropylene (PP)/iron oxide (Fe 2O 3) nanocomposites with highly dispersed nanoparticles (NPs). Transmission electron microscopy (TEM) observations confirm the uniform dispersion of NPs The melt rheology shows an obvious change in the frequency dependent storage modulus (G\u27), loss modulus (G ) and complex viscosity (ν*) particularly at low frequencies. These changes are often related to the NPs percolation threshold , which has also been verified in the sharp change of electrical resistance these nanocomposites in higher particle loadings. Thermal gravimetric analysis (TGA) results reveal a surprisingly high enhancement by ∼115 °C in thermal stability after the incorporation of the NPs. The differential scanning calorimetry (DSC) results show that the crystalline temperature (T c) of the nanocompsoites is reduced by 16-18 °C as compared to that of PP. The magnetic property of the nanocomposties is also investigated in this work