Introducing ADN students to nursing research

Every nurse, regardless of educational preparation, should be involved in and benefit from nursing research. The research process needs to become an integral part of nursing practice. In this article, the authors emphasize the importance of nursing research in the associate degree nursing curriculum, emphasizing strategies that enable the ADN graduate to appreciate research reports and use the knowledge in the clinical practice setting.

Developments in immunological standardization

In the century since Paul Erlich's innovative immunological standardization work with diphtheria anti-toxin, the field of immunological standardization has expanded dramatically. Biological standards for a diverse range of immunological substances have been produced e.g. immunoglobulins, complement components, autoantibodies and blood group reagents. The concept of calibration of such materials in biological units of potency is now widely accepted for many such substances. Most recently much effort has been devoted to producing biological standards for cytokines which can be used to calibrate and validate biological assays for these analytes. Immunoassays have been found to be particularly problematical from the standardization view point although provision of a single international standard for distribution world-wide is clearly advantageous and helps reduce assay variability. It is hoped that the considerable progress with immunological standardization achieved during the past century will continue and expand to ensure the validity of existing and new immunological assays which will be required in the future.

Interferon alpha primes early proliferative response of bone marrow cells in vivo

Using colony-forming assays, a number of previous studies established that interferon alpha (IFN-alpha) could cause bone marrow cell (BMC) suppression. In this study, the suppressive effect of IFN-alpha is however shown to be time-dependent, occurring only 7-8 days after transfer of BMC obtained from IFN-alpha-treated mice to growth factor-containing culture medium. In contrast, in the interval before suppression is observed, BMC obtained from IFN-alpha-treated mice initially proliferated more rapidly than BMC from placebo-treated mice. These findings suggest that IFN-alpha acts in vivo to prime the proliferative responses of BMC, a hitherto unexpected action which may have clinical relevance.

Laboratory protocols for the quantitation of cytokines by bioassay using cytokine responsive cell lines

Cytokines have been shown to be involved in many physiological processes, including the maintenance and control of a competent haematopoietic/immune system. Abnormal cytokine secretion or synthesis can cause a wide range of pathological disorders. Cytokines have also been shown to have therapeutic potential in many diseases. In order for the role of cytokines to be evaluated in normal and pathogenic processes, it is vital that appropriate assay systems are used to measure their levels in different biological fluids. Whilst immunoassays maybe a more convenient method for quantitating cytokines, they only measure immunologically reactive material. They may or may not detect biologically inactive material, such as cytokines bound to soluble receptors or degraded cytokine molecules. Bioassays, however, detect biologically active cytokines and can be as accurate and precise as immunoassays. The purpose of these protocols is to provide practical stepwise methods for the bioassay of cytokines using cytokine responsive cell lines. They include tables of the most useful currently available cell lines for the detection of cytokines and how to maintain them. In addition, these protocols provide all the materials and methods in a logical step-by-step procedure to carry out bioassays. Information is provided on possible pitfalls and general problems associated with bioassays and how to overcome them. These protocols should be valuable to scientists new to the cytokine field as well as experienced scientists who require a consensus methodology and access to information on cell lines useful for cytokine bioassays.

Human monoclonal antibodies encoded by the V4-34 gene segment show cold agglutinin activity and variable multireactivity which correlates with the predicted charge of the heavy-chain variable region

We have characterized the reactivities of a panel of V4-34-encoded human IgM monoclonal antibodies (mAb) which bind the erythrocyte Rh D antigen, derived from an immunized individual. These were compared with the specificities of V4-34-encoded autoantibodies with I/i reactivity produced from patients with cold agglutinin disease (CAD), and other V4-34-encoded autoantibodies. The antibodies were evaluated for cold agglutinin activity using haemagglutination tests, immunofluorescence microscopy for reactivity with tissue components, and in solid phase radiobinding assays with purified antigens. We found that (i) cold agglutinin activity was a property of all the V4-34-encoded mAb (ii) the cold agglutinins from CAD patients were generally monospecific for I/i whereas most of the anti-D and the other V4-34-encoded mAb displayed multireactive properties, frequently binding to strongly acidic antigens (iii) computation of the net charge of the heavy-chain V regions showed that the multireactive mAb were generally more positively charged than the monospecific cold agglutinins, which could contribute to their multireactive phenotype. The involvement of charge interactions was further indicated by the effects of pH and ionic strength on the immunofluorescence staining patterns.

The use of bioassays for the characterisation and control of biological therapeutic products produced by biotechnology

The primary value of bioassays is that they alone directly assess biological activity of bioactive substances and products. Appropriately designed bioassays reflect the fundamental aspects of the biological activity of a bioactive molecule, including ligand-receptor binding, signal transduction processes (often poorly understood) and the final observed biological effects. Biological assays therefore complement physicochemical and biochemical procedures which normally only assess precise molecular structural features of complex molecules produced by biotechnology. Bioassays provide valuable information concerning the potency of biological products. This is essential for evaluating batch-to-batch consistency and stability. Bioassay data are crucial at all stages in the development of biological products, from early research work to final quality control of finished products. However, the type and design of bioassays may differ according to the information required and its intended use. The assays may or may not directly relate to the clinical use of the product. Bioassays can be difficult to perform and be time consuming, although this often reflects bad assay choice and/or design. Correct analysis of the assay results is essential if valid data are to be obtained. Standardisation, using correctly calibrated primary and secondary standards, is essential. In vivo bioassays are normally more unreliable than in vitro procedures, but in some cases the latter are either not available or do not address important biological characteristics of a product. Bioassays must be validated for their intended purpose and for the types of samples to be measured. Appropriate statistical analysis should be used to derive the significance and specifications of results. This needs to address both variability in samples and assay performance. Specifications (limits) for product acceptability need to be derived from real data using several batches of product.

Are cytokines in platelet concentrates responsible for febrile transfusion reactions?

In recent years, several studies have identified the leukocyte content and the age of the blood components as dominant factors in febrile transfusion reactions (FTRs). At present, extensive efforts are being made to reduce adverse effects by implementation and/or introduction of new methods for leuko-depletion of blood components and by studying the mechanisms responsible for these phenomena. A recent approach has been the evaluation of cytokines in platelet concentrates and this issue has been addressed with some detail in this review. Comparative data currently available on levels of cytokines in the different platelet concentrates is provided along with the functional role of the detected cytokines in including adverse reactions.

Production and characterization of monoclonal antibodies to human interleukin-12

Interleukin-12 is a cytokine that plays a central role in mediating cell mediated immunity via enhancement of a TH1 cell response. IL-12, unusually for a cytokine, has a heterodimeric structure made up of 35 kDa and 40 kDa subunits. The aim of this study was to produce and characterize monoclonal antibodies to recombinant human IL-12. Twenty-two monoclonal antibodies to IL-12 were successfully produced and subunit specificity determined using recombinant human IL-12 and chimeric murine/human IL-12. All antibodies were shown to react with the p40 subunit by ELISA and immunoblotting with three of the MAbs being found to cross-react with murine IL-12. Using two individual bioassays for IL-12, seven of the MAbs were shown to neutralize biological activity of IL-12. Ten of the antibodies were found to be of use in immunocytochemistry, reacting with LPS-stimulated peripheral blood monocytes. The approaches and difficulties encountered in characterizing antibodies to a heterodimeric cytokine are discussed together with possible reasons for the failure to generate antibodies to the p35 subunit.

Suction dressings: a new surgical dressing technique

A new technique in surgical dressing is described which is a combination of a semi-permeable dressing and suction drainage. This dressing has been used successfully in 20 orthopaedic patients without any wound complication and with satisfactory comfort to the patient. This form of post-operative wound management appears to retain the nursing and hygiene advantages of suction drainage, whilst avoiding the patient discomfort and the possibilities of wound infection, associated with deep internal drainage.

Fighting, fleeing and having fun: the immunology of physical activity

Exercise places a spectrum of demands on the body, dependent on the form, intensity, and duration, which are super-imposed on a background of physiological and psychological factors peculiar to the host. Thus the net effect of these factors is both heterogeneous and complex. Studying the effects of exercise is dependent on an understanding of an elaborate network of interactions between the central nervous, endocrine, and immune systems that is yet to be understood. While investigators agree that immune suppression results from exhaustive exercise, opinions vary about its mechanism. Some of this is due to inter- and even intra-subject variation (perceptions, previous experience, gender, age, biological rhythms, other temporally related events, attributions, etc.), yet other is a result of differences in study design, parameters measured, methods and materials used, and a host of other variables. To achieve accord and to define the mechanisms leading to changes in health status, beneficial or harmful, that result from physical activity, we must strive to understand the complex network that exists in the psychoneuroendocrine immune system, design rigorous research models, standardize our methods, and offer sound hypotheses for future study. Lastly, investigations into exercise-induced immune alterations need to be conducted by multidisciplinary teams of individuals expert in each of the fields encompassed by this complex field of study. After offering some examples of the complex interactions between components of the psychoneuroendocrine immune axis, we discuss study design, caveats of laboratory methods, data reduction and interpretation, and a means of perhaps achieving our common goals in studying exercise immunology.

Cytokines in platelet concentrates: a comparison of apheresis platelet (haemonetics) and filtered and unfiltered pooled buffy-coat derived platelet concentrates

Variable degrees of platelet activation, shape changes, microvesiculation and fragmentation may occur during collection, processing and storage of platelet concentrates (PCs), contributing to different rate of platelet storage lesion. Leukocytes contribute to both the frequency of transfusion reactions and the acceleration of the rate of platelet storage lesion hence leukocyte removal of platelet concentrates has been introduced to overcome these problems. However transfusion reaction can still occur with the use of leuko-reduced products and it is not fully elucidated that the rate of storage lesion is equivalent for filtered and unfiltered counter parts. This issue has been addressed in this manuscript comparing the generation of cytokines during storage in PCs derived from pooled buffy coat with the standard apheresis products, with a similar level of leukocyte contamination. The EDTA-induced shape change in platelet was used as an index of platelet functional integrity. In addition IL-8 and TGF beta were used as indicators of filtration process-inducing stimulation of cytokines. Our results clearly indicate that a rapid disc/spheric conversion occurs during storage of buffy-coat derived PC, and while prestorage filtration reduces both IL-8 content immediately after filtration and at the end of platelet shelf life but such a process may lead to slight enhancement of the rate of TGF beta generation indicating that any additional process may have some bearing in stimulation of TGF beta release.

Implications for the assay and biological activity of interleukin-8: results of a WHO international collaborative study

Eight ampouled preparations of interleukin-8 (IL-8) have been evaluated for their suitability to serve as an international standard for IL-8 by 30 laboratories in 12 countries in an international collaborative study. The preparations were assayed in a wide range of in vitro bioassays and immunoassays. It is clear from the study that different recombinant preparations of IL-8 can have different biological specific activities, even though all were produced using E. coli. It is of interest that the intra-laboratory variability of estimates provided by several neutrophil degranulation bioassays was less than that of the immunoassays, suggesting that these bioassays can be as precise, if not more so, than immunoassays. In addition, immunoassay estimates of IL-8 preparations differed from those of bioassays, illustrating the fact that immunoassays do not necessarily measure biologically active cytokine. The large reduction in the inter-laboratory variability of estimates in terms of a common reference preparation clearly illustrates the need for a standard for IL-8. On the basis of the results reported here, with the agreement of the participants of the study and with the authorisation of the Expert Committee on Biological Standardization (ECBS) of the World Health Organization (WHO) the preparation of IL-8 (89/520) was established as the International Standard for IL-8 with an assigned unitage of 1000 IU/ampoule.

Treatment of metastatic renal cell carcinoma with subcutaneous interleukin 2: evidence for non-renal clearance of cytokines

The circulating cytokine concentrations following administration of subcutaneous recombinant interleukin 2 (IL-2) in combination with interferon alpha and 5-fluorouracil used to treat advanced renal cancer were studied. One patient was anephric and on dialysis, and seven had normal biochemical renal function, although five had undergone single nephrectomy. The pharmacokinetics of IL-2 and changes in IL-6 and tumour necrosis factor (TNF)-alpha were essentially similar in all patients including the anephric patient, irrespective of the periods of dialysis, although at some time points, IL-2 concentrations were slightly higher in the anephric patient than in the others. These results show that for subcutaneous administration of low-dose IL-2, renal clearance of IL-2 is not important. This contrasts with high-dose, intravenous IL-2 where blood concentrations are higher and renal clearance seems to occur, perhaps because of saturation of the non-renal mechanisms of clearance. The subcutaneous route is certainly preferred if IL-2 is used in anephric patients and in those with impaired renal function, and it may be generally preferred for most purposes.

IL-4 and TNF-alpha-mediated proliferation of the human megakaryocytic line M-O7E is regulated by induced autocrine production of GM-CSF

In this study, the authors examined the effects of recombinant human interleukin 4 (rhIL-4) and recombinant human tumour necrosis factor alpha (rhTNF-alpha) alone or in combination on proliferation of the human cytokine dependent myeloid cell line, M-O7e. While rhIL-4 or rhTNF-alpha alone induced only a weak proliferative response, a synergistic proliferative signal was clearly evident on stimulation of cells with a combination of both cytokines. The stimulatory effect of rhTNF-alpha is mediated predominantly by the 55-kDa TNF receptor because the agonistic monoclonal antibody htr-9 and the Trp32 Thr86 TNF-alpha mutant protein specific for this receptor type produced similar results to rhTNF-alpha. In contrast, the Asn143 Arg145 TNF-alpha mutant protein specific for the 75-kDa TNF receptor produced only minimal proliferation of M-O7e cells. Using RT-PCR, we found that rhTNF-alpha rapidly and strongly induced granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNA production, while rhIL-4 was a slow and less efficient inducer of GM-CSF mRNA. However, there was little evidence of the TNF-alpha/IL-4 combination acting synergistically on GM-CSF mRNA production as the levels of GM-CSF mRNA increased only marginally compared with IL-4 or TNF-alpha alone. Thus, the observed synergistic effect of TNF-alpha/IL-4 costimulation of M-O7e cells seems to be mediated via induction of GM-CSF secretion rather than an enhanced production of GM-CSF mRNA. Higher levels of GM-CSF were detectable in supernatants of cells treated with both rhIL-4 and rhTNF-alpha than in cells stimulated with either cytokine alone. Furthermore, addition of a neutralising antibody against GM-CSF abrogated the observed synergistic effect of rhIL-4 and rhTNF-alpha treatment, indicating that the rhIL-4/TNF-alpha combination acts to significantly increase GM-CSF release which then acts in an autocrine manner to enhance the proliferation of M-O7e cells.

An anti-cytokine bioactivity assay for interferons-alpha, -beta and -omega

Interferons-alpha and -beta (IFN-alpha and -beta) are cytokines that are widely known to induce potent anti-viral activity. However, it has become increasingly apparent that IFN-alpha and -beta exert a variety of other biological effects, including anti-tumour and immunomodulatory activities and are increasingly used clinically to treat a range of malignancies, myelodysplasias and autoimmune diseases, e.g., IFN-beta for multiple sclerosis. The most widely used bioassays for the IFNs are based on their anti-viral activity, but these do not predict the biological activity of the IFNs in anti-tumour and immunomodulatory therapies. Thus, we have developed anti-cytokine-based bioassays that may be more reflective of such activity and which have several advantages over existing anti-viral bioassays. The anti-cytokine bioassay is based on the ability of IFN-alpha, -beta and -omega to inhibit granulocyte-macrophage-colony-stimulating factor (GM-CSF) induced proliferation of the erythroleukaemic cell line TF-1. This assay can take only 24 h, is sensitive to 200 fg (0.04 IU) IFN-alpha or -beta and 100 fg (0.02 IU) IFN-omega and is able to detect down to these levels in serum or plasma samples. The usefulness of anti-cytokine bioassays for IFN-alpha, -beta and -omega is not restricted to the GM-CSF/TF-1 cell format and other alternatives are available, such as erythropoietin (EPO)/TF-1 cells and EPO/UT-7-EPO cells. These assays can be made specific for each of the IFNs by including neutralising antibodies in the bioassay.

The biological properties, assay, and standardization of interferon-alpha: a need for a WHO collaborative study

Interferon-alpha (IFN-alpha) exists as a range of closely related, biologically active proteins and has been the subject of extensive research and clinical investigation. Standardization of IFN-alpha and the uniform reporting of IFN-alpha activity in International Units (IU) is critical to preclinical research and the clinical development of IFN-alpha products as therapeutic agents. Currently, several different IFN-alpha-containing reference preparations, established as World Health Organization (WHO) International Standards (IS) for particular IFN-alpha proteins (mixtures or single molecular species) are available for assay calibration. Nevertheless, the heterogeneous nature of IFN-alpha has raised standardization issues relating to the activity of individual IFN-alpha proteins, hence-forth termed subtypes, in the various biologic assays used for determining IFN-alpha levels. These issues include the question of parallelism of dose-response curves among particular IFN-alpha subtypes and different, naturally produced IFN-alpha subtype mixtures, for example, leukocyte IFN-alpha, and the applicability of IU of IFN-alpha activity defined by antiviral assays to alternative biologic assays, for example, antiproliferative assays. To address such issues, a WHO Consultative Group on Cytokine Standardization requested that the National Institute for Biological Standards and Control (NIBSC) and the Centre for Biologics Evaluation and Research (CBER) organize an international collaborative study to compare the activities and relative potencies of the several available IFN-alpha preparations, including those derived from human cells containing mixtures of IFN-alpha subtypes and those derived by rDNA methods containing single IFN-alpha subtypes, in different assays. To date, 111 participants in 32 countries have been recruited to the study and have agreed to assay a total of 17 different natural and recombinant IFN-alpha preparations or a defined subset thereof in specific in-house assays. The assay results generated will be statistically analyzed and evaluated to address the stated issues and to assess whether any individual IFN-alpha preparation is suitable to serve as an IS for all IFN-alpha preparations or whether more than one IS will be needed for this purpose.

Implications for the assay and biological properties of interleukin-3. Results of a WHO international collaborative study

Five preparations of interleukin-3 (IL-3) have been evaluated by 28 laboratories in 12 countries for their suitability to serve as an international standard for this material in a joint international collaborative study for IL-3 and interleukin-4 (IL-4). The preparations were assayed in a wide range of in vitro bioassays and immunoassays. It is clear from the biological assays contributed to this study that different recombinant preparations of IL-3 can have very different biological specific activities, including those from the same source (i.e., E. coli). Biological assays of IL-3 were significantly more consistent in their estimates of levels of IL-3 than the immunoassays, suggesting an unusual pattern of epitope recognition amongst the antibodies included in the immunoassays. This study also illustrates the point that the level of cytokine measured by immunoassay does not necessarily reflect the biological potency of the cytokine. On the basis of results reported here, with the agreement of the participants of the study and with the authorisation of the Expert Committee on Biological Standardization (ECBS) of the World Health Organization (WHO) the preparation of IL-3 (91/510) was established as the international standard for interleukin-3 with an assigned unitage of 1700 IU/ampoule.

Implications for the assay and biological activity of interleukin-4. Results of a WHO international collaborative study

Five ampouled preparations of interleukin-4 (IL-4) have been evaluated by 36 laboratories in 14 countries for their suitability to serve as an international standard for this material in a joint international collaborative study for interleukin-3 (IL-3) and IL-4. The preparations were assayed in a wide range of in vitro bioassays and immunoassays. It is clear from the study that different recombinant preparations of IL-4 can have very different biological specific activities, including those from the same source (i.e., E. coli). In addition, immunoassay estimates of IL-4 levels did not correlate with those of bioassays, illustrating the fact that immunoassays do not necessarily measure biologically active cytokine. It is of interest that the estimates provided by the different bioassays were less variable than those produced by the immunoassays, suggesting that bioassays can be as accurate, if not more so, than immunoassays. The large reduction in the variability of estimates with the inclusion of a single reference preparation clearly illustrates the need for a single standard to assay IL-4. On the basis of the results reported here, with the agreement of the participants of the study and with the authorisation of the Expert Committee on Biological Standardization (ECBS) of the World Health Organization (WHO) the preparation of IL-4 (88/656) was established as the international standard for interleukin-4 with an assigned unitage of 1000 IU/ampoule.

Testing plasma pools for markers of viral contamination: the UK experience

The transmission of viral infections through the use of products derived from blood has emphasised the need for adequate validation of the production process, testing of materials used in production and quality control tests on the final product. Since the late 1980s, as part of its batch release procedures, NIBSC has tested for markers of viral infectivity plasma pools used in production of blood products used in the UK. As a result of testing over 9,000 pools, NIBSC has identified 9 pools contaminated with HBsAg and 2 pools containing antibodies to HIV-1. Since routine screening of plasma pools for anti-HCV was introduced in 1993, 8 pools out of the 4,000 tested have been found to contain antibodies to HCV. In addition, the release of 12 batches of blood products was withheld and it is known that further batches of material produced from the positive pools were not submitted for batch release. Studies involving assays of dilutions of known positive plasma samples indicated that there is considerable variation in the endpoint dilutions of antigen or antibody detected by test kits from different manufactures. The selection and validation of the kits used in such testing is therefore important. The usefulness of standardised low-level external controls in assays of plasma pools for markers of viral infection is discussed.

Production of neutralizing granulocyte-macrophage colony-stimulating factor (GM-CSF) antibodies in carcinoma patients following GM-CSF combination therapy

In this study, the development of neutralizing and non-neutralizing GM-CSF antibodies and the clinical consequences related to the induction of these antibodies were analysed in 20 patients with metastatic colorectal carcinoma receiving a combination therapy of Escherichia coli-derived GM-CSF and a colon carcinoma-reactive MoAb in the absence of any concomitant chemotherapy. The recombinant human GM-CSF was administered subcutaneously for 10 days every month for 4 months. Following the first cycle of treatment, no GM-CSF antibodies were detected, but during subsequent therapy, 19 of the 20 patients studied developed GM-CSF binding antibodies. However, only a proportion (40%) of the 19 antibody-positive patients developed antibodies that neutralized the biological activity of GM-CSF in an in vitro bioassay. The presence of GM-CSF neutralizing antibodies was associated with a significant reduction in GM-CSF-induced expansion of leucocytes, neutrophils and eosinophils. Such clinical effects were not apparent in patients with non-neutralizing antibodies. Further characterization of sera from patients with neutralizing antibodies showed that, in most cases, the antibodies neutralized the biological activity of GM-CSF preparations derived using different expression systems (Chinese hamster ovary cells and yeast), suggesting that these antibodies may have the potential to cross-react with endogenously produced GM-CSF. These effects should be considered before therapeutic use of cytokines, particularly in patients who are not immunosuppressed, and therefore capable of mounting an effective immune response. Our results indicate that assessment of production of neutralizing antibodies induced during cytokine therapy can be used to predict diminished clinical response to further therapy.