Efficient homolactic fermentation by Kluyveromyces lactis strains defective in pyruvate utilization and transformed with heterologous LDH gene

A high yield of lactic acid per gram of glucose consumed and the absence of additional metabolites in the fermentation broth are two important goals of lactic acid production by microrganisms. Both purposes have been previously approached by using a Kluyveromyces lactis yeast strain lacking the single pyruvate decarboxylase gene (KlPDC1) and transformed with the heterologous lactate dehydrogenase gene (LDH). The LDH gene was placed under the control the KlPDC1 promoter, which has allowed very high levels of lactate dehydrogenase (LDH) activity, due to the absence of autoregulation by KlPdc1p. The maximal yield obtained was 0.58 g/g, suggesting that a large fraction of the glucose consumed was not converted into pyruvate. In a different attempt to redirect pyruvate flux toward homolactic fermentation, we used K. lactis LDH transformant strains deleted of the pyruvate dehydrogenase (PDH) E1alpha subunit gene. A great process improvement was obtained by the use of producing strains lacking both PDH and pyruvate decarboxylase activities, which showed yield levels of as high as 0.85 g/g (maximum theoretical yield, 1 g/g), and with high LDH activity

Obesity promotes the expansion of metastasis-initiating cells in breast cancer

Obesity is a strong predictor of poor prognosis in breast cancer, especially in postmenopausal women. In particular, tumors in obese patients tend to seed more distant metastases, although the biology behind this observation remains poorly understood.Methods: To elucidate the effects of the obese microenvironment on metastatic spread, we ovariectomized C57BL/6 J female mice and fed them either a regular diet (RD) or a high-fat diet (HFD) to generate a postmenopausal diet-induced obesity model. We then studied tumor progression to metastasis of Py230 and EO771 grafts. We analyzed and phenotyped the RD and HFD tumors and the surrounding adipose tissue by flow cytometry, qPCR, immunohistochemistry (IHC) and western blot. The influence of the microenvironment on tumor cells was assessed by performing cross-transplantation of RD and HFD tumor cells into other RD and HFD mice. The results were analyzed using the unpaired Student t test when comparing two variables, otherwise we used one-way or two-way analysis of variance. The relationship between two variables was calculated using correlation coefficients.Results: Our results show that tumors in obese mice grow faster, are also less vascularized, more hypoxic, of higher grade and enriched in CD11b+Ly6G+ neutrophils. Collectively, this favors induction of the epithelial-to-mesenchymal transition and progression to claudin-low breast cancer, a subtype of triple-negative breast cancer that is enriched in cancer stem cells. Interestingly, transplanting HFD- derived tumor cells in RD mice transfers enhanced tumor growth and lung metastasis formation.Conclusions: These data indicate that a pro-metastatic effect of obesity is acquired by the tumor cells in the primary tumor independently of the microenvironment of the secondary site

Overdose of quetiapine—A case report with QT prolongation

Quetiapine is an atypical antipsychotic drug used to treat bipolar disorder, schizophrenia, and major depressive disorder. Although several studies describe the adverse effects of intoxication with Quetiapine, only a few report an extreme overdose without comedications that lead to a life threat. We present a case of a 75-year-old male who tried to attempt suicide by ingesting 28 g of Quetiapine. During the management in the emergency department, both serum and urine samples were collected, allowing a complete pharmacokinetic analysis to be conducted, from the admission to the discharge

Population attributable risk of modifiable risk factors associated with invasive breast cancer in women aged 45-69 years in Queensland, Australia

Objectives To quantify the population attributable risk of key modifiable risk factors associated with breast cancer incidence in Queensland, Australia. Study design Population attributable fractions (PAFs) for high body mass index (BMI), use of hormone replacement therapy (HRT), alcohol consumption and inadequate physical activity were calculated, using prevalence data from a representative survey of women attending mammographic screening at BreastScreen Queensland in 2008 and relative risk estimates sourced from published literature. Attributable cancers were calculated using 'underlying' breast cancer incidence data for 2008 based on Poisson regression models, adjusting for the inflation of incidence due to the effects of mammographic screening. Main outcome measures Attributable burden of breast cancer due to high body mass index (BMI), use of hormone replacement therapy (HRT), alcohol consumption and inadequate physical activity. Results In Queensland women aged 45-69 years, an estimated 12.1% (95% CI: 11.6-12.5%) of invasive breast cancers were attributable to high BMI in post-menopausal women who have never used HRT; 2.8% (95% CI: 2.7-2.9%) to alcohol consumption; 7.6% (95% CI: 7.4-7.9%) to inadequate physical activity in post-menopausal women and 6.2% (95% CI: 5.5-7.0%) to current use of HRT after stratification by BMI and type of HRT used. Combined, just over one quarter (26.0%; 95% CI: 25.4-26.6%) of all invasive breast cancers in Queensland women aged 45-69 years in 2008 were attributable to these modifiable risk factors. Conclusions There is benefit in targeting prevention strategies to modify lifestyle behaviours around BMI, physical activity, HRT use and alcohol consumption, as a reduction in these risk factors could decrease invasive breast cancer incidence in the Queensland population