In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Q: Context: The blasticidin S resistance gene (bsr) is a selectable marker used for gene transfer experiments. The bsr gene encodes for blasticidin S (BS) deaminase, which has a specific activity upon BS. Therefore, its expression is supposed to be harmless in cells. The work reported on herein consisted of experiments to verify a possible toxicity of bsr on mammalian cells, which include several cell lines and primary cultures.', 'Murine keratinocyte BALB/MK and human primary keratinocyte cells transduced with the retroviral vector LBmSN, which has an improved expression system of bsr, namely bsrm, died in five days after the transduction. Meanwhile the control vector LBSN, which expresses bsr, did not provoke cell death. The lethal activity of bsrm was observed only in human keratinocytes and BALB/MK cells among the cell types tested here. Death appears to be mediated by a factor, which is secreted by the BALB/MK transduced cells.\Question: Is over expression of the selectable marker blasticidin S deaminase gene toxic to human keratinocytes and murine BALB/MK cells?

A: By our study we demonstrated that the expression of bsrm gene is toxic to human keratinocytes and BALB/MK cells. It is likely over expression of BS deaminase gene is responsible for the death.
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Q: Context: The aim of this study was to evaluate the characteristics of low-energy femoral insufficiency fractures in elderly patients.', 'The study retrospectively evaluated the clinical course of 4 patients with low-energy femoral shaft and subtrochanteric fractures admitted to our department between 2009 and 2011. Three patients had prior long-term alendronate therapy and one had prior glucocorticoid therapy.', 'There were 5 femoral shaft fractures, 2 incomplete shaft fractures, 2 subtrochanteric and 1 intertrochanteric fractures. All femoral shaft fractures had characteristic fracture patterns with thickened lateral cortices at the proximal fragment. Six femurs had excessive medial femoral bowing, which complicated intramedullary nailing. Additional fractures were seen on both femurs of one patient who had been primarily treated with short implants. A bifocal femoral fracture was seen in one femur. Union was achieved in all patients. Two patients were able to walk independently, one with a cane and one with double crutches.\Question: Does femoral insufficiency fractures in the elderly - excessive medial femoral bowing complicate intramedullary nailing?

A: We suggest the addition of another radiographic pattern of 'excessive medial femoral bowing' in low-energy femoral shaft fractures in elderly patients. This bowing complicates intramedullary nailing. Moreover, these insufficiency fractures should be fixed with long cephalomedullary nails.
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Q: Context: The lowest peak expiratory flow (PEF) over a week, expressed as a percentage of the highest PEF (Min%Max PEF) has been reported to be the index that most closely correlates with airway hyperresponsiveness (AHR) in asthmatics. However, both fluctuation of the airway caliber and airflow limitation are regarded as physiological properties of asthma closely related to AHR. An accurate index that shows the degree of AHR may be obtained by combining the index of airway lability with the parameters that represent airway caliber.', 'Ninety-two steroid-naive and twenty-eight steroid-treated asthmatic patients were enrolled. Using the physiological parameters obtained from spirometry and PEF monitoring, we investigated the indices which correlate accurately with airway responsiveness measured by the inhalation challenge test.', 'Although the methacholine threshold was related to all parameters that represent airway caliber and lability, Min%Max PEF had the strongest correlation with AHR. When Min%Max PEF was adjusted by the airway geometric factors, the normalization of Min%Max PEF with forced expiratory volume in one second as a percentage of the predicted value (%FEV(1)) improved the relationship between Min%Max PEF and AHR.\Question: Is peak expiratory flow variability adjusted by forced expiratory volume in one second a good index for airway responsiveness in asthmatics?

A:
Min%Max PEF adjusted by %FEV(1) showed a good correlation with airway responsiveness measured by the inhalation challenge test, and may be useful as a convenient alternative index of AHR in asthmatic patients.
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