Search

The production of ethanol and methane from corn stover (CS) was investigated in a biorefinery process. Initially, a novel soaking pretreatment (NaOH and aqueous-ammonia) for CS was developed to remove lignin, swell the biomass, and improve enzymatic digestibility. Based on the sugar yield during enzymatic hydrolysis, the optimal pretreatment conditions were 1 % NaOH+8 % NH(4)OH, 50°C, 48 h, with a solid-to-liquid ratio 1:10. The results demonstrated that soaking pretreatment removed 63.6 % lignin while reserving most of the carbohydrates. After enzymatic hydrolysis, the yields of glucose and xylose were 78.5 % and 69.3 %, respectively. The simultaneous saccharification and fermentation of pretreated CS using Pichia stipitis resulted in an ethanol concentration of 36.1 g/L, corresponding only to 63.3 % of the theoretical maximum. In order to simplify the process and reduce the capital cost, the liquid fraction of the pretreatment was used to re-soak new CS. For methane production, the re-soaked CS and the residues of SSF were anaerobically digested for 120 days. Fifteen grams CS were converted to 1.9 g of ethanol and 1337.3 mL of methane in the entire process.

Background: Precursor B-acute lymphoblastic leukemia occurring in patients with a history of malignancies is uncommon, and this condition is not well understood., Design and Methods: A retrospective review of 457 adults with precursor B-acute lymphoblastic leukemia treated at our hospital identified 44 (9.6%) patients with prior malignancies. The clinical and genetic characteristics of this group of patients was compared with those of their counterparts with de novo disease and the relationship with prior chemoradiation therapy was assessed., Results: Thirty of 44(6.2%) patients received cytotoxic therapies, whereas 14 patients did not. The former group showed a significantly shorter interval from prior malignancy to onset of precursor B-acute lymphoblastic leukemia (36 versus 144 months; P = 0.002). Compared with 413 de novo cases, the frequencies of t(4;11)(q21;q23) (P<0.001) and hypodiploidy (P = 0.009) with loss of chromosome 5, 7 or 17 were significantly higher in patients who received topoisomerase II inhibitor and/or alkylating agents. By contrast, Philadelphia-positive and normal karyotype were more frequent in patients who either did not receive chemotherapy or received only local radiation or nucleoside analogs. Patients with precursor B-acute lymphoblastic leukemia following prior malignancies and chemoradiation were older, had a lower complete remission rate and showed an inferior survival in univariate, but not multivariate analysis., Conclusions: The data support the interpretation that therapy-related precursor B-acute lymphoblastic leukemia does occur. In particular, cases associated with t(4;11)(q21;q23) or hypodiploidy with -5, -7, -17 are likely to be therapy-related and have a poor prognosis. The inferior outcome of these patients may be attributable to the high-risk cytogenetic abnormalities that are found in this group of patients.

Trisomy 11 (+11) as an isolated abnormality is a rare event in patients with acute myeloid leukemia (AML) and is associated with poor prognosis. We describe the clinicopathologic features of 18 AML patients with isolated +11 and their mutation status of NPM1, FLT3, NRAS ,KRAS, and KIT. Fourteen patients had de novo AML and 4 patients had a history of myelodysplastic syndrome (MDS). Fifteen patients had a progressive clinical course with refractory or relapsed disease. The median overall survival was 5 months (range, 2 to 48 months). Only 1 patient achieved complete remission after undergoing stem cell transplantation. The bone marrow median blast count was 65% (range, 22 to 86) and 14 patients had blasts >50%. The most common type of AML was AML without maturation (7 patients) classified by the World Health Organization classification system, or M1 (10 patients) by the French-American-British (FAB) system. FLT3 mutations were detected in 3 of 15 (20%) cases tested. RAS mutation was present in 1 of 16 (6%) cases and there was no evidence of NPM1 of KIT mutations (each tested in 12 cases). Our findings confirm previous reports that isolated +11 is associated with a poor prognosis in patients with AML and tends to be associated with FAB-M1 morphologic features. No evidence of NPM1 or KIT mutations were identified.

Biomarkers to predict response to therapy in adults with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) are not yet established. In this study, we performed a meta-analysis of earlier genome-wide gene expression studies to identify pathway-based genes that are associated with therapeutic response. The predictive power of these genes was validated by transcript profiling in diagnostic bone marrow samples from Ph+ ALL patients using a quantitative real-time PCR array. Gene expression was correlated with cytogenetic and molecular characteristics, including presence of ABL1 mutations and IKZF1 deletion. A total of 43 de novo Ph+ ALL patients treated uniformly with tyrosine kinase inhibitors combined with chemotherapy were selected to validate 46 identified genes. A 9-gene signature was established to distinguish optimal responders from patients with persistent residual disease and early molecular recurrence. The signature was subsequently validated with 87% predictive accuracy in an independent validation set of patients. When initially optimal responders relapsed, their gene expression patterns also shifted. Optimal responders showed upregulation of genes involved in proliferation and apoptosis pathways, whereas poor responders had higher expression of genes that facilitate tumor cell survival in hypoxic conditions as well as development of drug resistance. This unique 9-gene signature may better enable stratification of patients to proper therapeutic regimens and provides new insights into mechanisms of Ph+ ALL response to therapy.

The diagnostic criteria for acute erythroid leukemia have been controversial since this disease was initially described. Using the current World Health Organization classification criteria, we retrospectively reviewed cases of acute myeloid leukemia or myelodysplastic syndrome in which erythroid precursors were >or=50% of the bone marrow nucleated cell population and the diagnosis of erythroleukemia was considered using older classification schemes. We collected 90 cases and separated them into four diagnostic groups: acute erythroid leukemia, erythroleukemia or erythroid/myeloid type (n=20); acute myeloid leukemia with myelodysplasia-related changes (n=22); therapy-related acute myeloid leukemia (n=32); and refractory anemia with excess blasts and preceding or concurrent history of erythropoietin therapy for anemia (n=16). Patients with acute erythroid leukemia were the youngest patient group and had the best overall survival. There was a statistically significant difference in overall survival between patients with acute erythroid leukemia versus acute myeloid leukemia with myelodysplasia-related changes (P=0.003) and between patients with acute erythroid leukemia versus therapy-related acute myeloid leukemia (P<0.0001). The presence of complex cytogenetic abnormalities (>3) was the only statistically significant independent variable that adversely affected survival in the acute erythroid leukemia group. Monosomy 5/del(5q) and monosomy 7/del(7q) were overrepresented in the context of complex chromosomal abnormalities. Our data suggest that acute erythroid leukemia, as currently defined in the World Health Organization classification, has become a rare disease. A majority of the cases reported previously as erythroleukemia are now classified as other entities. In addition, our data suggest that the current definition of acute erythroid leukemia, erythroleukemia type remains heterogeneous. One subset of acute erythroid leukemia patients has relatively low blast counts and are diploid. The prognosis of this patient subset is relatively good. The other subset has cytogenetic abnormalities similar to those in myelodysplastic syndromes and a poor prognosis.

Acute erythroid leukemia (AEL) is a rare type of acute myeloid leukemia (AML) for which diagnostic criteria have been refined in the 2008 World Health Organization (WHO) classification of AML. The relationship of AEL to myelodysplastic syndromes (MDSs) and to AML with myelodysplasia-related changes (AML-MRC) is not clearly defined. We conducted a retrospective, multi-institutional study of patients with AEL and compared them with patients with MDS or AML-MRC with erythroid hyperplasia (> or = 50% erythroid cells). Among a total of 124 patients with AEL, 32% had a history of MDS or chronic cytopenia, 32% had therapy-related disease, and 35% had de novo disease. Sixty-four percent of patients had unfavorable AML risk-group karyotypes. FLT3 and RAS mutations were infrequent, occurring in 6% and 2%, respectively. The median overall survival (OS) of all AEL patients was 8 months, comparable with that of patients with MDS or AML-MRC with erythroid hyperplasia. The OS was related to cytogenetic risk group, but not blast count or morphologic dysplasia. Our findings suggest that AEL is in the continuum of MDS and AML with erythroid hyperplasia, where karyotype rather than an arbitrary blast cutoff represents the most important prognostic factor.

KRAS mutations have been detected in approximately 30% of all human tumors, and have been shown to predict response to some targeted therapies. The most common KRAS mutation-detection strategy consists of conventional PCR and direct sequencing. This approach has a 10-20% detection sensitivity depending on whether pyrosequencing or Sanger sequencing is used. To improve detection sensitivity, we compared our conventional method with the recently described co-amplification-at-lower denaturation-temperature PCR (COLD-PCR) method, which selectively amplifies minority alleles. In COLD-PCR, the critical denaturation temperature is lowered to 80 degrees C (vs 94 degrees C in conventional PCR). The sensitivity of COLD-PCR was determined by assessing serial dilutions. Fifty clinical samples were used, including 20 fresh bone-marrow aspirate specimens and the formalin-fixed paraffin-embedded (FFPE) tissue of 30 solid tumors. Implementation of COLD-PCR was straightforward and required no additional cost for reagents or instruments. The method was specific and reproducible. COLD-PCR successfully detected mutations in all samples that were positive by conventional PCR, and enhanced the mutant-to-wild-type ratio by >4.74-fold, increasing the mutation detection sensitivity to 1.5%. The enhancement of mutation detection by COLD-PCR inversely correlated with the tumor-cell percentage in a sample. In conclusion, we validated the utility and superior sensitivity of COLD-PCR for detecting KRAS mutations in a variety of hematopoietic and solid tumors using either fresh or fixed, paraffin-embedded tissue.