An overview of mechanistic modeling of liquid chromatography

Abstract

Liquid chromatography is considered to be the bottleneck for purification of therapeutic proteins. Development and optimization of chromatography process is a cumbersome activity due to the increasing complexities in the types and content of impurities present in the high product titer cell culture harvest obtained from the upstream processing. Further, regulatory expectations are continuously rising with the recent initiatives of quality by design and process analytical technology expecting the manufacturer to have a deeper understanding of the process and the product. Mechanistic modeling is one approach to gain this deeper understanding of a process step. It involves modeling of the underlying physicochemical processes. A well calibrated model with acceptable predictability can be very effective in both process optimization and process characterization activities. In this paper we provide an overview of mechanistic modeling of liquid chromatography. We discuss the various components that such a model entails and also presents the status quo of this area.     

Selective ozone concentrations may reduce the ischemic damage after a stroke

Abstract Stroke is one of the most debilitating diseases, and it is unfortunate that only a small percentage of patients can be treated with thrombolytic agents. Consequently, there is an urgent need of finding an alternative procedure for reoxygenating the so-called penumbra at the earliest time as possible for reducing morbidity and disability. A preliminary, preclinical study has been carried out by using rat hippocampal and cortical brain slices subjected to oxygen-glucose deprivation. Oxygen-ozone gaseous mixture appeared to be effective in reverting damage of brain tissues, supporting the evaluation of this approach in well-designed clinical trials in stroke patients.     

Novel molecular targets for prevention of obesity and osteoporosis

Evidence from both epidemiological studies and basic research suggests that obesity and osteoporosis are interrelated. Though there is an increase in the prevalence of these disorders, a limited number of treatments are available, one of the reasons being the complexity of the pathways involved and difficulty in identifying a single molecular target. Due to adverse effects of pharmaceuticals, intake of herbal drugs by patients without a physician's recommendation is increasing globally. Lack of success with targeted monotherapy has encouraged scientists to determine whether combinations of phytochemicals that interfere with numerous cell-signaling pathways can be a more effective approach to treat complex diseases. For example, evidence is emerging that specific combinations of phytochemicals are far more effective than single compounds in decreasing adipogenesis and promoting bone formation. Since multiple pathways are dysfunctional in obesity and osteoporosis, an ideal approach for preventing and treating these diseases may be to use a combination of phytochemicals to address several targets simultaneously.     

Natural selection as an emergent process: instructional implications

Student reasoning about cases of natural selection is often plagued by errors that stem from miscategorising selection as a direct, causal process, misunderstanding the role of randomness, and from the intuitive ideas of intentionality, teleology and essentialism. The common thread throughout many of these reasoning errors is a failure to apply ‘population thinking’. Students fail to recognise that natural selection refers to changes in the distribution of certain traits at the population level, the collective, resulting from interactions between individual organisms and their environment at the next lower level in the system. Processes like selection are emergent processes in hierarchical systems, where patterns in a collective are generated by interactions at the lower level. By helping students develop an emergent process schema that enables them to recognise that even random interactions at one level in a system can generate predictable patterns at a higher level, their understanding of natural selection should improve. Some studies have shown this to be an effective approach for teaching other emergent processes. Instructional recommendations based on these studies are presented here, but more research is needed to determine the full extent to which this approach can improve students’ understanding.     

Allocation procedure in multi-output process: an illustration of ISO 14041

Allocation results for a multi-output process in a life cycle assessment study depend on the definition of the unit process which can vary with the depth of a study. The unit process may be a manufacturing site, a sub-process, or an operational unit (e.g. distillation column or reactor). There are three different approaches to define a unit process: macroscopic approach, quasi-microscopic approach, and microscopic approach. In the macroscopic approach, a unit process is the manufacturing site, while a unit process in the quasi-microscopic approach is a sub-process of the manufacturing site. An operational unit becomes the unit process in the microscopic approach. In the quasi-microscopic and the microscopic approaches, a process can be subdivided into a joint process, a physically separated process which is physically apart from other processes, and a fully separated process. Each type can be a unit process. Therefore, the multi-output process in the quasi-microscopic and the microscopic approaches can be subdivided among two or more unit processes depending on the actual operations. The allocation in the fully separated process can be avoided because this process fulfills one function. In the joint process and the physically separated process, which deliver two or more functions, allocation is still required. Ammonia manufacturing, where carbon dioxide is formed as a byproduct is given to show a specific detailed example of the allocation procedure by subdivision in ISO 14041. It is shown that the quasi-microscopic and the microscopic approaches can reduce the multi-output allocation of a given chemical product. Furthermore, the quasi-microscopic and the microscopic approaches are very useful in identifying key pollution prevention issues related with one product or function.     

Selective ozone concentrations may reduce the ischemic damage after a stroke

Abstract

Stroke is one of the most debilitating diseases, and it is unfortunate that only a small percentage of patients can be treated with thrombolytic agents. Consequently, there is an urgent need of finding an alternative procedure for reoxygenating the so-called penumbra at the earliest time as possible for reducing morbidity and disability. A preliminary, preclinical study has been carried out by using rat hippocampal and cortical brain slices subjected to oxygen-glucose deprivation. Oxygen-ozone gaseous mixture appeared to be effective in reverting damage of brain tissues, supporting the evaluation of this approach in well-designed clinical trials in stroke patients.     

Renal denervation: a new treatment option in resistant arterial hypertension

Hypertension is one of the most prevalent cardiovascular risk factors. Despite this high prevalence and a broad availability of effective pharmaceutical agents, a significant proportion of patients do not reach treatment goals. Partly this can be explained by secondary causes of hypertension or non-compliance of patients. Nevertheless, a subgroup of patients can be diagnosed with ‘resistant hypertension’. Activation of the sympathetic nervous system is known to be an important factor in the development and progression of systemic hypertension. In this context, a percutaneous, catheter–based approach has been developed using radiofrequency energy to disrupt renal sympathetic nerves. The first studies have shown this technique to be safe, illustrated by a lack of vascular or renal injury. More importantly, catheter-based renal nerve ablation resulted in a significant reduction in blood pressure on top of traditional medical therapy. Additional to the encouraging effects shown on hypertension, a positive influence of this intervention in other conditions, characterised by sympathetic overactivation, may be expected. Though this technique seems promising, further studies are needed to address long-term safety and efficacy of renal denervation in hypertension and other disease states.     

Stem Cell Therapy: A New Therapeutic Option for Cardiovascular Diseases

Cardiovascular diseases are known as one of major causes of morbidity and mortality worldwide. Despite the many advancement in therapies are associated with cardiovascular diseases, it seems that finding of new therapeutic option is necessary. Cell therapy is one of attractive therapeutic platforms for treatment of a variety of diseases such as cardiovascular diseases. Among of various types of cell therapy, stem cell therapy has been emerged as an effective therapeutic approach in this area. Stem cells divided into multipotent stem cells and pluripotent stem cells. A large number studies indicated that utilization of each of them are associated with a variety of advantages and disadvantages. Multiple lines evidence indicated that stem cell therapy could be used as suitable therapeutic approach for treatment of cardiovascular diseases. Many clinical trials have been performed for assessing efficiency of stem cell therapies in human. However, stem cell therapy are associated with some challenges, but, it seems resolving of them could contribute to using of them as effective therapeutic approach for patients who suffering from cardiovascular diseases. In the current review, we summarized current therapeutic strategies based on stem cells for cardiovascular diseases. J. Cell. Biochem. 119: 95–104, 2018. © 2017 Wiley Periodicals, Inc.     

Use of liposomes as drug delivery vehicles for treatment of melanoma

Melanoma is a progressive disease that claims many lives each year due to lack of therapeutics effective for the long‐term treatment of patients. Currently, the best treatment option is early detection followed by surgical removal. Better melanoma therapies that are effectively delivered to tumors with minimal toxicity for patients are urgently needed. Nanotechnologies provide one approach to encapsulate therapeutic agents leading to improvements in circulation time, enhanced tumor uptake, avoidance of the reticulo‐endothelial system, and minimization of toxicity. Liposomes in particular are a promising nanotechnology that can be used for more effective delivery of therapeutic agents to treat melanoma. Liposomes delivering chemotherapies, siRNA, asODNs, DNA, and radioactive particles are just some of the promising new nanotechnology based therapies under development for the treatment of melanoma that are discussed in this review.     

Macromusophagy: A solo piano musical representation of macroautophagy

Macroautophagy is a complex process involving dynamic membrane rearrangements in which parts of the cytoplasm are sequestered within double-membrane phagophores. Upon completion, these structures mature into autophagosomes that fuse with the yeast vacuole or mammalian lysosome, leading to degradation of the cargo and release of the resulting macromolecules back into the cytosol. How can the complexities of macroautophagy best be conveyed to an audience that is composed primarily of people who are not experts in this topic, and possibly not even scientists? The literature on learning is vast, and difficult to summarize, but there are certain themes that frequently appear. First, people learn in different ways. Thus, for example, while lectures are effective for conveying information to part of the audience, some will benefit tremendously from alternative methods of presentation. The latter can be visual (taking the form of illustrations, videos, or even physical movement), tactile or audible. Second, a line of research suggests that the engagement of more than one part of the brain (dual channels) improves learning. We decided to explore these concepts focusing on an audible format through a collaborative approach by combining a scientific explanation of macroautophagy with a musical score that was composed specifically to represent this process.     

Early detection of high disease activity in juvenile idiopathic arthritis by sequential monitoring of patients' health-related quality of life scores

Juvenile idiopathic arthritis (JIA) is a chronic disease. During its “high disease activity (HDA)” stage, JIA can cause severe pain, and thus could seriously affect patients' physical and psychological health. Early detection of the HDA stage of JIA can reduce the damage of the disease by treating it at an early stage and alleviating the painful experience of the patients. So far, no effective cure of JIA has been found, and one major goal of disease management is to improve patients' quality of life. To this end, patients' health-related quality of life (HRQOL) scores are routinely collected over time from JIA patients. In this paper, we demonstrate that a new statistical methodology called dynamic screening system (DySS) is effective for early detection of the HDA stage of JIA. By this approach, a patient's HRQOL scores are monitored sequentially, and a signal is given by DySS once the longitudinal pattern of the scores is found to be significantly different from the pattern of patients with low disease activity. Dimension reduction of the observed HRQOL scores and the corresponding impact on the performance of DySS are also discussed.     

Quantitation of minimal residual disease in patients with chronic lymphocytic leukemia using locked nucleic acid-modified, fluorescently labeled hybridization probes and real-time PCR technology

BACKGROUND: The knowledge of biological characteristics of minimal residual disease (MRD) in chronic lymphocytic leukemia (CLL) remains sparse. There are no data available on what level of MRD might be 'safe' without an overt risk of relapse, or whether any such level exists at all. To address this issue in prospective studies, we have developed a quantitative molecular approach to monitor MRD in CLL, which allows the malignant clone to be traced with far higher sensitivity than possible with the techniques available currently. METHOD: To quantify MRD in CLL patients, a novel locked nucleic acid (LNA)-RNA-based quantitative real-time PCR technique was developed. Clone-specific assays were prepared for 62 CLL patients. Thirty patients were followed up molecularly for a median of 250 days (range 69-570 days). All patients were administered chemo/immunotherapy. RESULTS: In three patients, molecular negativity was achieved, as estimated by LNA-based assays. In one patient, a sustained molecular negativity was established by chemo/immunotherapy and the patient remains molecularly negative (322 days). The LNA-based assay enabled us to evaluate MRD in a reproducible manner with the sensitivity of 10(-7). CONCLUSION: LNA-RNA-based quantitative real-time PCR is an effective approach for MRD monitoring with the potential for increased sensitivity compared with standard DNA-based assays used for molecular follow-up.     

Finite Element Method (FEM) Modeling of Freeze-drying: Monitoring Pharmaceutical Product Robustness During Lyophilization

Lyophilization is an approach commonly undertaken to formulate drugs that are unstable to be commercialized as ready to use (RTU) solutions. One of the important aspects of commercializing a lyophilized product is to transfer the process parameters that are developed in lab scale lyophilizer to commercial scale without a loss in product quality. This process is often accomplished by costly engineering runs or through an iterative process at the commercial scale. Here, we are highlighting a combination of computational and experimental approach to predict commercial process parameters for the primary drying phase of lyophilization. Heat and mass transfer coefficients are determined experimentally either by manometric temperature measurement (MTM) or sublimation tests and used as inputs for the finite element model (FEM)-based software called PASSAGE, which computes various primary drying parameters such as primary drying time and product temperature. The heat and mass transfer coefficients will vary at different lyophilization scales; hence, we present an approach to use appropriate factors while scaling-up from lab scale to commercial scale. As a result, one can predict commercial scale primary drying time based on these parameters. Additionally, the model-based approach presented in this study provides a process to monitor pharmaceutical product robustness and accidental process deviations during Lyophilization to support commercial supply chain continuity. The approach presented here provides a robust lyophilization scale-up strategy; and because of the simple and minimalistic approach, it will also be less capital intensive path with minimal use of expensive drug substance/active material.     

The choice of allogeneic or autologous hematopoietic transplantation for NHL

NHL constitutes the sixth most common malignancy diagnosed in the USA every year, accounting for approximately 24,400 deaths. Although a subset of patients can be cured with chemotherapy or radiation therapy, the outlook is generally poor for patients with refractory or recurrent disease. High-dose therapy supported by both autologous and allogeneic transplantation has been widely studied in this group of patients. Autologous transplantation may be considered standard therapy for patients with diffuse large-cell NHL in chemotherapy-sensitive relapse. Selected categories of patients with other histologic subtypes may also benefit from this strategy. Allogeneic transplantation using high-dose myeloablative conditioning regimen is an effective, yet hazardous approach. A GvL effect leads to a lower rate of disease recurrence than occurs with autologous transplants, but this benefit is offset by higher risk of treatment related mortality. The recent use of less toxic non-myeloablative conditioning regimens for allogeneic transplantation has reduced the risk of transplant-related mortality, allowing this approach even in older or medically infirm patients. Nonablative allogeneic transplants are a promising strategy, particularly for patients with indolent lymphoid malignancies.     

The physician as a patient educator. From theory to practice.

Patient nonadherence to therapeutic regimens is a serious issue in the practice of medicine. Empiric studies done by professionals from diverse backgrounds have shown that physicians who use educational strategies can be effective in gaining the cooperation of patients to follow their recommendations. The educational model that currently is most familiar to physicians and the one they use most frequently when educating patients is pedagogy, the theoretic basis for teaching children. Andragogy, a theoretic basis for teaching adults, is now being suggested by medical educators as an alternative model. To illustrate the clinical relevance and application of the andragogic approach, studies focusing on physician behaviors associated with behavioral measures of adherence were reviewed, analyzed, and categorized according to a framework called the "ADULT" model. Physicians in a postgraduate training program who have had exposure to this framework and have incorporated it into their practices report less difficulty functioning as patient educators. The systematic use of this approach can have a positive effect on patient adherence.     

High-throughput ex vivo drug testing identifies potential drugs and drug combinations for NRAS-positive malignant melanoma

Therapy options for patients with metastatic melanoma (MM) have considerably improved over the past decade. However, many patients still need effective therapy after unsuccessful immunotherapy, especially patients with BRAF-negative tumors who lack the option of targeted treatment second line. Therefore, the elucidation of efficient and personalized therapy options for these patients is required. In this study, three patient-derived cancer cells (PDCs) were established from NRAS Q61-positive MM patients. The response of PDCs and five established melanoma cell lines (two NRAS-positive, one wild type, and two BRAF V600-positive) was evaluated toward a panel of 527 oncology drugs using high-throughput drug sensitivity and resistance testing. The PDCs and cell lines displayed strong responses to MAPK inhibitors, as expected. Additionally, the PDCs and cell lines were responsive to PI3K/mTOR, mTOR, and PLK1 inhibitors among other effective drugs currently undergoing clinical trials. Combinations with a MEK inhibitor were tested with other targeted agents to identify effective synergies. MEK inhibitor showed synergy with multikinase inhibitor ponatinib, ABL inhibitor nilotinib, PI3K/mTOR inhibitor pictilisib, and pan-RAF inhibitor LY3009120. The application of the patients’ cancer cells for functional drug testing ex vivo is one step further in the process of identifying potential agents and agent combinations to personalize treatment for patients with MM. Our preliminary study results suggest that this approach has the potential for larger-scale drug testing and personalized treatment applications in our expansion trial. Our results show that drug sensitivity and resistance testing may be implementable in the treatment planning of patients with MM.     

Predementia Alzheimer's disease. Benefits of early diagnosis

Given population aging and the rise in the number of persons with Alzheimer's disease, measures that aim not only to delay but also to prevent the development of this disease are increasingly required. Advances in the diagnosis of Alzheimer's disease support the need for a review of current clinical standards for mild cognitive impairment and provide new goals in the early treatment of this disease. The current diagnostic process should be refocussed toward the pathological substrate of this disease rather than symptoms in order to initiate therapeutic measures as soon as possible without waiting for clinical manifestations to appear. Such an approach is essential in patients with greater cognitive reserve, in whom the lesions are usually more severe at diagnosis and treatment is less effective. To identify disease-modifying therapies to delay the onset of the clinical symptoms of Alzheimer's disease in cognitively intact persons at high risk, biomarkers for this disease must be validated. A single biomarker is unlikely to provide the required diagnostic accuracy and therefore a multimodal approach, incorporating biochemical, neuropathological and anatomical and metabolic neuroimaging methods, should be employed. To optimize the results of drugs under investigation, a combination of biomarkers should be used to select appropriate participants in the earliest phases of the disease, and disease progression should be followed-up. Early diagnosis might clarify essential questions in the care of patients with Alzheimer's disease, such as the possibility of distinguishing among various subtypes, thus encouraging the development of optimal treatments for each. The ultimate goal is to develop disease-modifying treatments that could be initiated early, while patients are asymptomatic or only minimally symptomatic, to maintain their quality of life.     

Comparison of data science workflows for root cause analysis of bioprocesses

Root cause analysis (RCA) is one of the most prominent tools used to comprehensively evaluate a biopharmaceutical production process. Despite of its widespread use in industry, the Food and Drug Administration has observed a lot of unsuitable approaches for RCAs within the last years. The reasons for those unsuitable approaches are the use of incorrect variables during the analysis and the lack in process understanding, which impede correct model interpretation. Two major approaches to perform RCAs are currently dominating the chemical and pharmaceutical industry: raw data analysis and feature-based approach. Both techniques are shown to be able to identify the significant variables causing the variance of the response. Although they are different in data unfolding, the same tools as principal component analysis and partial least square regression are used in both concepts. Within this article we demonstrate the strength and weaknesses of both approaches. We proved that a fusion of both results in a comprehensive and effective workflow, which not only increases better process understanding. We demonstrate this workflow along with an example. Hence, the presented workflow allows to save analysis time and to reduce the effort of data mining by easy detection of the most important variables within the given dataset. Subsequently, the final obtained process knowledge can be translated into new hypotheses, which can be tested experimentally and thereby lead to effectively improving process robustness.