RESUMEN
A novel, alternative intensified cell culture process comprised of a linked bioreactor system is presented. An N-1 perfusion bioreactor maintained cells in a highly proliferative state and provided a continuous inoculum source to a second bioreactor operating as a continuous-flow stirred-tank reactor (CSTR). An initial study evaluated multiple system steady-states by varying N-1 steady-state viable cell densities, N-1 to CSTR working volume ratios, and CSTR dilution rates. After identifying near optimum system steady-state parameters yielding a relatively high volumetric productivity while efficiently consuming media, a subsequent lab-scale experiment demonstrated the startup and long-term operation of the envisioned manufacturing process for 83 days. Additionally, to compensate for the cell-specific productivity loss over time due to cell line instability, the N-1 culture was also replaced with younger generation cells, without disturbing the steady-state of the system. Using the model cell line, the system demonstrated a two-fold volumetric productivity increase over the commercial-ready, optimized fed-batch process.
Asunto(s)
Productos Biológicos/metabolismo , Reactores Biológicos , Animales , Técnicas de Cultivo Celular por Lotes/instrumentación , Células CHO , Cricetulus , Diseño de Equipo , Perfusión/instrumentaciónRESUMEN
In order to address the increasing demand for biologics, cell culture intensification using perfusion offers significantly higher productivities while also reducing manufacturing costs, especially when part of an integrated, continuous bioprocess. An initial study of a long-duration perfusion process using a cell-bleed to maintain a target cell density observed a 2.1-fold higher cell-specific productivity and a gradual decline in the culture growth rate when perfused at an overall lower rate. Subsequent studies sought an alternative process that largely reduced the overall volume of media needed by first perfusing at a high cell-specific perfusion rate (CSPR) to support a high cell density followed by continued perfusion at a low CSPR to promote a more productive stationary phase. This high intensity, low-volume perfusion (HILVOP) process achieved cumulative volumetric productivities of 1.5-1.6 g/L/day with two CHO cell lines. When compared to each cell line's respective commercial-ready, fed-batch process, a 3.1-3.8-fold productivity increase was demonstrated while yielding similar product quality. Furthermore, the higher productivity achieved with HILVOP used 6.6-12.3-fold less media than a similarly productive long-duration process. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1472-1481, 2018.
Asunto(s)
Técnicas de Cultivo Celular por Lotes/métodos , Reactores Biológicos , Animales , Células CHO , Cricetinae , CricetulusRESUMEN
A simple method originally designed to control lactate accumulation in fed-batch cultures of Chinese Hamster Ovary (CHO) cells has been modified and extended to allow cells in culture to control their own rate of perfusion to precisely deliver nutritional requirements. The method allows for very fast expansion of cells to high density while using a minimal volume of concentrated perfusion medium. When the short-duration cell-controlled perfusion is performed in the production bioreactor and is immediately followed by a conventional fed-batch culture using highly concentrated feeds, the overall productivity of the culture is approximately doubled when compared with a highly optimized state-of-the-art fed-batch process. The technology was applied with near uniform success to five CHO cell processes producing five different humanized monoclonal antibodies. The increases in productivity were due to the increases in sustained viable cell densities. Biotechnol. Bioeng. 2017;114: 1438-1447. © 2017 Wiley Periodicals, Inc.
Asunto(s)
Técnicas de Cultivo Celular por Lotes/métodos , Células CHO/citología , Células CHO/fisiología , Proliferación Celular/fisiología , Glucosa/metabolismo , Ácido Láctico/metabolismo , Perfusión/métodos , Animales , Técnicas de Cultivo Celular por Lotes/instrumentación , Reactores Biológicos , CricetulusRESUMEN
UNLABELLED: Introduction Hospitals are meant to be places for respite and healing; however, technological advances and reliance on monitoring alarms has led to the environment becoming increasingly noisy. The coronary care unit (CCU), like the emergency department, provides care to ill patients while being vulnerable to noise pollution. The World Health Organization (WHO; Geneva, Switzerland) recommends that for optimum rest and healing, sound levels should average approximately 30 decibels (dB) with maximum readings less than 40 dB. Problem The purpose of this study was to measure and analyze sound levels in three different locations in the CCU, and to review alarm reports in relation to sound levels. METHODS: Over a one-month period, sound recorders (Extech SDL600; Extech Instruments; Nashua, New Hampshire USA) were placed in three separate locations in the CCU at the West Roxbury Veterans' Administration (VA) Hospital (Roxbury, Massachusetts USA). Sound samples were recorded once per second, stored in Comma Separated Values format for Excel (Microsoft Corporation; Redmond, Washington USA), and then exported to Microsoft Excel. Averages were determined, plotted per hour, and alarm histories were reviewed to determine alarm noise effect on total noise for each location, as well as common alarm occurrences. RESULTS: Patient Room 1 consistently had the lowest average recordings, though all averages were >40 dB, despite decreases between 10:00 pm and 7:00 am. During daytime hours, recordings maintained levels >50 dB. Overnight noise remained above recommended levels 55.25% of the period in Patient Room 1 and 99.61% of the same time period in Patient Room 7. The nurses' station remained the loudest location of all three. Alarms per hour ranged from 20-26 during the day. Alarms per day averaged: Patient Room 1-57.17, Patient Room 7-122.03, and the nurses' station - 562.26. Oxygen saturation alarms accounted for 33.59% of activity, and heart-related (including ST segment and pacemaker) accounted for 49.24% of alarms. CONCLUSION: The CCU cares for ill patients requiring constant monitoring. Despite advances in technology, measured noise levels for the hospital studied exceeded WHO standards of 40 dB and peaks of 45 dB, even during night hours when patients require rest. Further work is required to reduce noise levels and examine effects on patient satisfaction, clinical outcomes, and length of stay. Ryan KM , Gagnon M , Hanna T , Mello B , Fofana M , Ciottone G , Molloy M . Noise pollution: do we need a solution? An analysis of noise in a cardiac care unit. Prehosp Disaster Med. 2016;31(4):432-435.
Asunto(s)
Instituciones Cardiológicas/normas , Ruido/prevención & control , Habitaciones de Pacientes/normas , Instituciones Cardiológicas/estadística & datos numéricos , Exposición a Riesgos Ambientales/efectos adversos , Exposición a Riesgos Ambientales/estadística & datos numéricos , Humanos , Monitoreo Fisiológico/efectos adversos , Monitoreo Fisiológico/instrumentación , Monitoreo Fisiológico/métodos , Ruido/efectos adversos , Habitaciones de Pacientes/estadística & datos numéricosRESUMEN
Obesity has been a topic of intense interest in the United States for several years. Rising rates of obesity have led some to question whether or not America will be able to readily sustain a fit fighting force into the future. This study seeks to describe at what point, projecting current trends in obesity and military accession, there would no longer be a sufficient number of qualified applicants to support an effective military fighting force. By analyzing trends in national obesity data and military accession records, the authors were unable to determine a realistic time projection of a year in which the United States would no longer be able to find enough qualified military applicants as a result of increasing obesity rates.
Asunto(s)
Medicina Militar/tendencias , Personal Militar , Obesidad/epidemiología , Selección de Personal/tendencias , Predicción , Humanos , Estados Unidos/epidemiologíaRESUMEN
A simple method for control of lactate accumulation in suspension cultures of Chinese hamster ovary (CHO) cells based on the culture's pH was developed. When glucose levels in culture reach a low level (generally below 1 mM) cells begin to take up lactic acid from the culture medium resulting in a rise in pH. A nutrient feeding method has been optimized which delivers a concentrated glucose solution triggered by rising pH. We have shown that this high-end pH-controlled delivery of glucose can dramatically reduce or eliminate the accumulation of lactate during the growth phase of a fed-batch CHO cell culture at both bench scale and large scale (2,500 L). This method has proven applicable to the majority of CHO cell lines producing monoclonal antibodies and other therapeutic proteins. Using this technology to enhance a 12-day fed-batch process that already incorporated very high initial cell densities and highly concentrated medium and feeds resulted in an approximate doubling of the final titers for eight cell lines. The increase in titer was due to additional cell growth and higher cell specific productivity.