Energy cost of infection burden: an approach to understanding the dynamics of host-pathogen interactions

A mathematical model of long-term immune defense against infection was used to estimate the energy involved in the principal processes of immune resistance during periods of health and infection. From these values, an optimal level of energy was determined for immune response depending on infection burden. The present findings suggest that weak but prevalent pathogens lead to latent or chronic infection, whereas more virulent but less prevalent pathogens result in acute infection. This energy-based approach offers insight into the mechanisms of immune system adaptation leading to the development of chronic infectious diseases and immune deficiencies.     

Paired analysis of tumor mutation burden calculated by targeted deep sequencing panel and whole exome sequencing in non-small cell lung cancer

Owing to rapid advancements in NGS (next generation sequen-cing), genomic alteration is now considered an essential pre-dictive biomarkers that impact the treatment decision in many cases of cancer. Among the various predictive biomarkers, tumor mutation burden (TMB) was identified by NGS and was con-sidered to be useful in predicting a clinical response in cancer cases treated by immunotherapy. In this study, we directly com-pared the lab-developed-test (LDT) results by target sequencing panel, K-MASTER panel v3.0 and whole-exome sequencing (WES) to evaluate the concordance of TMB. As an initial step, the reference materials (n = 3) with known TMB status were used as an exploratory test. To validate and evaluate TMB, we used one hundred samples that were acquired from surgically resected tissues of non-small cell lung cancer (NSCLC) patients. The TMB of each sample was tested by using both LDT and WES methods, which extracted the DNA from samples at the same time. In addition, we evaluated the impact of capture re-gion, which might lead to different values of TMB; the evalu-ation of capture region was based on the size of NGS and target sequencing panels. In this pilot study, TMB was evalu-ated by LDT and WES by using duplicated reference samples; the results of TMB showed high concordance rate (R² = 0.887). This was also reflected in clinical samples (n = 100), which showed R² of 0.71. The difference between the coding sequence ratio (3.49%) and the ratio of mutations (4.8%) indicated that the LDT panel identified a relatively higher number of mutations. It was feasible to calculate TMB with LDT panel, which can be useful in clinical practice. Furthermore, a customized approach must be developed for calculating TMB, which differs according to cancer types and specific clinical settings.     

Enhancing Safety,Security, and Environmental Protection of the Straits of Malacca and Singapore: The Cooperative Mechanism

In November 2004, the International Maritime Organization, as part of its Protection of Vital Shipping Lanes Initiative, decided to convene a high-level conference to address the security of ships plying the Straits of Malacca and Singapore in collaboration with the three littoral states of Indonesia, Malaysia, and Singapore. Three meetings were held over the period 2005 to 2007. The outcome was the creation of a framework for cooperation between the users of the straits and the littoral states known as the Cooperative Mechanism, a historic breakthrough as Article 43 of the Law of the Sea Convention was implemented for the first time. This article outlines the decisions made at the three meetings, analyzes the responses of the various stakeholders during the meetings, explains the reasons for the success of the Cooperative Mechanism, and concludes by proposing ways in which the momentum of cooperation between the users and the littoral states could be sustained.     

Being a burden to others and wishes to die: The importance of the sociopolitical context

All articles in May 2019’s special issue of Bioethics offer profound insights into the issue of “being a burden to others” in relation to wishes to die, which are highly relevant for ethical debates about end-of-life care and physician-assisted dying. In this reply, we wish to stress the importance of acknowledging and analyzing the sociopolitical context of the phenomenon “being a burden” in relation to wishes to die and we will show how this analysis could benefit from a care ethical approach. As discussions in care ethics have made clear, caring practices are both social and political practices. An empirical and ethical analysis of “being a burden” therefore needs to take institutional and societal norms and structures into account, in addition to first-person experiences and concepts such as caring needs, relational autonomy, and interdependency. Besides the relevance of the sociopolitical context for the phenomenon “being a burden” as such, the sociopolitical context also seems relevant for the investigation of the phenomenon, which we will illustrate by reflecting on “being a burden” in relation to the practice of physician-assisted dying in the Netherlands.     

Metabolic adaptation of Escherichia coli during temperature-induced recombinant protein production: 1. Readjustment of metabolic enzyme synthesis

The metabolic burden and the stress load resulting from temperature-induced production of human basic fibroblast growth factor is connected to an increase in the respiratory activity of recombinant Escherichia coli, thereby reducing the biomass yield. To study the underlying changes in metabolic enzyme synthesis rates, the radiolabeled proteom was subjected to two-dimen- sional gel electrophoresis. After temperature-induction, the cAMP-CRP controlled dehydrogenases of the pyruvate dehydrogenase complex and the tricarboxylic acid cycle (LpdA and SdhA) were induced four times, reaching a maximum 1 h after the temperature upshift. The more abundant tricarboxylic acid cycle dehydrogenases (Icd and Mdh) were initially produced at reduced rates but regained preshift rates within 30 min. The adenylate energy charge dropped immediately after the temperature upshift but recovered within 1 h. Similar profiles in dehydrogenase synthesis rates and adenylate energy charge were found in a control cultivation of a strain carrying the "empty" parental expression vector. Although both strains exhibited significant differences in growth pattern and respiration rates after the temperature upshift, the adaptation of the energetic state of the cells and the synthesis of enzymes from the energy-generating catabolic pathway did not seem to be affected by the strong overproduction of the recombinant growth factor. In contrast, the synthesis rates of enzymes belonging to the biosynthetic machinery, e.g., translational elongation factors, decreased more strongly in the culture synthesizing the recombinant protein. In control and producing culture, synthesis rates of elongation factors paralleled the respective growth rate profiles. Thus, cells seem to readjust their metabolic activities according to their energetic requirements and, if necessary, at the cost of their biosynthetic capabilities.     

Epidemiological characteristics and disease burden of infectious mononucleosis in hospitalized children in China: A nationwide retrospective study

Epstein-Barr virus (EBV) is very common, with the infection rate in adults over 90% worldwide. Infectious mononucleosis (IM) is caused by primary infection with EBV. Most IM patients are generally considered to have a favorable prognosis, but a few patients will also develop complications. Children with severe symptoms will require hospitalization. However, the disease burden of children hospitalized with IM in China has been rarely described. In this study, we included the Face sheets of discharge medical records from 27 member children's hospitals of Futang Research Center of Pediatric Development from Jan 1st, 2016 to Dec 31st, 2020, and medical information such as gender, age, region, time of admission, length of stay and expenditure were extracted. There were 24,120 IM cases, which accounted for 0.42% (24,120/5,693,262) of all hospitalized cases during this period. The ratio of male to female was 1.48:1. Hospitalization for IM in the 4–6 years age group was the highest among inpatients of all age groups. Case numbers increased year by year between 2016 and 2020, and the monthly hospitalization was generally high from Jul to Sep but reduced from Jan to Feb per year. Bronchitis/pneumonia and hepatic dysfunction were two common complications in hospitalized IM patients. The median length of stay was 8 days, and the median cost of hospitalization was 970.59 US dollars. This study will help understand the epidemiological characteristics and disease burden of hospitalized children with IM in China.     

Limiting the metabolic burden of recombinant protein expression during selection yields pools with higher expression levels

In order to avoid the metabolic burden of protein expression during cell growth, and to avoid potential toxicity of recombinant proteins, microbial expression systems typically utilize regulated expression vectors. In contrast, constitutive expression vectors have usually been utilized for isolation of protein expressing mammalian cell lines. In mammalian systems, inducible expression vectors are typically utilized for only those proteins that are toxic when overexpressed. We developed a tetracycline regulated expression system in CHO cells, and show that cell pools selected in the uninduced state recover faster than those selected in the induced state even though the proteins showed no apparent toxicity or expression instability. Furthermore, cell pools selected in the uninduced state had higher expression levels when protein expression was turned on only in production cultures compared to pools that were selected and maintained in the induced state through production. We show a titer improvement of greater than twofold for an Fc-fusion protein and greater than 50% improvement for a recombinant antibody. The improvement is primarily due to an increase in specific productivity. Recombinant protein mRNA levels correlate strongly with protein expression levels and are highest in those cultures selected in the uninduced state and only induced during production. These data are consistent with a model where CHO cell lines with constitutive expression select for subclones with lower expression levels.     

检测HIV-1载量的荧光实时定量PCR技术的建立及其应用

准确测定HIV-1的前病毒载量和病毒载量的技术,在感染者预后和艾滋病患者药物治疗效果的评价以及艾滋病的其它研究方面,都具有十分重要的应用价值。以定量的HIV-1DNA和RNA为标准外参照,利用SYBRGreen荧光染料和GeneAmp5700 Sequence Detection System(5700系统),建立了测定HIV-1的前病毒载量和病毒载量的荧光实时定量PCR技术。以病毒感染细胞和培养上清为材料,测定了三种化合物(AZT,GL和WT)对细胞内的前病毒载量和培养上清中的病毒载量的抑制活性,并与合胞体形成抑制方法测定化合物抗病毒活性的结果进行了比较。根据病毒载量、前病毒载量和合胞体形成计算出的三种化合物的治疗指数均依次变小,提出以荧光实时定量PCR技术测定前病毒载量,会在评价药物在体内外根除或减少存在于CD4休止或记忆T淋巴细胞中的HIV-1前病毒方面有特别的价值。