Pre-clinical safety evaluation of pyrrolidine dithiocarbamate.

Pyrrolidine dithiocarbamate (PDTC) was examined for its potential in the intranasal treatment of human rhinovirus infections. Prior to clinical testing, a comprehensive non-clinical programme was performed to evaluate the general toxicity of PDTC. The animal experiments included investigations in rodents with study durations ranging from single dose to repeated dosing over a period of 28 days.

Detachment factors for enhanced carrier to carrier transfer of CHO cell lines on macroporous microcarriers.

In this publication different detachment factors were tested for enhancing carrier to carrier transfer for scale-up of macroporous microcarrier based bioprocesses. Two Chinese hamster ovary cell lines, CHO-K1 and a genetically engineered CHO-K1 derived cell line (CHO-MPS), producing recombinant human Arylsulfatase B, were examined. The cells were grown on Cytoline 1microcarriers (Amersham Biosciences, Uppsala, Sweden) in protein-free and chemically defined medium respectively.

Scalable inoculation strategies for microcarrier-based animal cell bioprocesses.

Scalability is a major demand for high-yield, stable bioprocess systems in animal cell culture-based biopharmaceutical production. Increased yields can be achieved through high-density cell culture, such as in the combination of microcarrier and fluidized bed bioreactor technology. To minimize inocula volume in industrial applications of fluidized bed fermentation systems, it is crucial to increase the bed volume in the reactor during the fermentation process.

Comparison of fluidized bed and ultrasonic cell-retention systems for high cell density mammalian cell culture.

Economically viable biopharmaceutical production is to a high degree dependent on high product yields and stable fermentation systems that are easy to handle. In the current study we have compared two different fermentation systems for the production of recombinant protein from CHO cells. Both systems are fully scaleable and can be used for industrial high cell density bioprocesses.

Influence of carboxymethyl dextran and ferric citrate on the adhesion of CHO cells on microcarriers.

Due to the inherent risks of animal-derived raw materials, the biopharmaceutical industry has an increasing demand for serum-free and protein-free media for industrial cell culture bioprocesses. The absence of serum often changes the characteristics of mammalian cells, especially growth, productivity, and adherence properties. This study is mainly focused on the influence of media additives on cell adherence characteristics.

A study of the spatial organisation of microbial cells in a gel matrix subjected to treatment with ultrasound standing waves.

Retention and manipulation of microbial cells through exploitation of ultrasonic forces has been reported as a novel cell immobilisation technique. The spatial ordering of yeast cells, within suspensions subjected to an ultrasonic standing wave field, was analysed for the first time. A technique, based on 'freezing' the spatial arrangement using polymer gelation was developed.

Breakdown of immobilisation/separation and morphology changes of yeast suspended in water-rich ethanol mixtures exposed to ultrasonic plane standing waves.

Some physiological/morphological changes have been reported before, when suspended yeasts have been irradiated with well-defined ultrasonic standing, as well as propagating, plane waves around 2.2 MHz, as used in ultrasonic coagulation, e.g.

Biosafety: future priorities for research in health care.

Currently the public interest in biosafety issues has focussed on the discussions surrounding the use of genetically modified organisms, very specifically on the use of transgenic plants in agriculture. Although many of the questions raised in connection with genetically modified organisms are of legitimate scientific interest, attention should be drawn back to a number of other more classical biosafety research areas, namely the problem of control of new and reemerging infectious diseases, the need for new vaccines, control of transport and routes of dissemination, biosafety information exchange and networking, where research results are dearly needed. In the area of modern biotechnology new applications such as gene therapy and transgenic animals will be on the list of future priorities for biosafety related activities and research.

Viability of yeast cells in well controlled propagating and standing ultrasonic plane waves.

Recent studies have shown that there is no loss of cell viability when the cells are subjected to ultrasonic standing wave fields in acoustic cell retention systems. These systems are characterised by waves that spatially vary in pressure amplitude in the direction of sound propagation. In this work an anechoic 'one-dimensional' sonication chamber has been developed that produces propagating waves, which differ from standing waves in that the pressure amplitude remains constant as the wave travels in a medium with negligible attenuation.

Safe biotechnology 9: values in risk assessment for the environmental application of microorganisms. The Safety in Biotechnology Working Party of the European Federation of Biotechnology.

Risk assessment for the deliberate release of microorganisms into the environment is traditionally carried out on a case-by-case basis. In a similar approach to that used when assessing human pathogenicity, we propose an alternative approach by introducing risk classes to facilitate or complement this type of risk assessment. These consider several sets of scenarios that address the different values that need to be protected.

Quality control and assurance from the development to the production of biopharmaceuticals.

Consumer and patient safety have become the prerequisites for (bio)pharmaceutical product development, production and marketing. The ability to provide an effective, pure, safe product is the primary factor determining the product's success. However, with an ever-increasing number of national and international regulations, 'quality assurance' has acquired a threatening ring for many project managers.

Safe biotechnology. 8. Transport of infectious and biological materials. Working Party "Safety in Biotechnology" of the European Federation of Biotechnology.

The transport of infectious and biological material is regulated by a number of international organizations. This mini-review has been compiled to increase awareness within the scientific community of problems caused by differences in terminology (such as infectious materials/substances, biological products, diagnostic specimens, genetically modified microorganisms) and certain technical aspects of the main international guidelines, and to assist policy makers in the creation of harmonized guidelines. A list of relevant Internet resources has been compiled.

Expression of foreign proteins on the surface of Autographa californica nuclear polyhedrosis virus.

Based on the method of direct cloning into the baculovirus genome by linearizing and re-ligation in presence of the target insert, we designed viral constructs that express foreign genes on the surface of baculovirus particles. We chose the glycosylated envelope protein gp41 of human immunodeficiency virus type 1 (HIV-1) as a model for displaying recombinant proteins on budded virus. The ectodomain of the envelope protein gp41 of HIV-1 was being fused to the entire baculovirus major coat protein gp64 (Ac-cops41) and to the membrane anchor sequence of gp64 (Acmars41).

Safe biotechnology. 7. Classification of microorganisms on the basis of hazard. Working Party "Safety in Biotechnology" of the European Federation Biotechnology.

The current systems for classifying human pathogens on the basis of hazard are well developed and their basic criteria are in general agreement one with another. Of more importance, the safety practices based on these classifications have generally been successful. They have enabled extensive research activities, medical practice and industrial production to be conducted on an ever-increasing scale, involving dangerous microorganisms (e.

Selective retention of viable cells in ultrasonic resonance field devices.

A double-chamber ultrasonic resonance field device was used for the separation and retention of animal cells. By controlling operational parameters such as flow and power input, the device can retain viable cells more efficiently, allowing for selective removal of nonviable cells and cell debris. A simple model describing the forces acting on spherical particles in a sound field (primary radiation force, Bernoulli force, secondary radiation force) is presented.

Safe biotechnology. Part 6. Safety assessment, in respect of human health, of microorganisms used in biotechnology.

The assessment of microorganisms in respect to human health is an important step for the introduction of new natural and genetically modified production strains to biotechnology. This report outlines the potential hazards posed by industrial microorganisms, important considerations related to pathogenicity, such as routes and portals of entry into the human body, mechanisms of spread of biological material and a definition of pathogenicity. Furthermore the most important steps in the assessment of pathogenicity of unknown strains are described.

A novel ultrasonic resonance field device for the retention of animal cells.

This article describes two types of flow-through cell retention devices based on the concept of layered piezoelectric resonators. A single-chamber device is compared to a novel optimized steam-sterilizable prototype ultrasonic cell separator with improved acoustic design and an integrated cooling circuit, eliminating the problem of local temperature increase caused by the high amplitudes necessary to achieve the separation of animal cells with low acoustic contrast. This setup yields highly reproducible results and is ideal for studying the long-term effects of ultrasonic sound fields and separation efficiency.

Stable, continuous large-scale production of human monoclonal HIV-1 antibody using a computer-controlled pilot plant.

A completely automated pilot plant used for fermentation has been employed with direct digital control (DDC) technology for monitoring and regulating growth of human cells. A human hybridoma cell line (3D6) producing anti-human immunodeficiency virus (HIV)-1 antibodies was used as a model for large-scale production (300-liter airlift fermentor) in continuous culture. Parameters controlled were pH, dissolved oxygen, temperature and the flow rate of four gases used in the process.

Safe biotechnology (5). Recommendations for safe work with animal and human cell cultures concerning potential human pathogens.

The benefits of using animal or human cell cultures have been clearly demonstrated in diagnostic and therapeutic research and in their application for manufacturing. Cell cultures serve as a tools for the production of vaccines, receptors, enzymes, monoclonal antibodies and recombinant DNA-derived proteins. They represent an integral part of drug development for which corresponding facilities, equipment and manufacturing processes are required.

Modular integrated fluidized bed bioreactor technology.

We describe the design and demonstrate the application of a modular integrated fluidized bed bioreactor system. Basically the system is a reactor vessel equipped with an extending cylinder and a liquid distributor plate. Instead of an external recirculation loop, as used in existing fluidized bed systems, a low shear stress impeller is used as the recirculation pump.