Ethics in Animal-Based Research

Chemoprevention by Microencapsulated Lactiplantibacillus Plantarum LAB12 Against Orthotopic Colorectal Cancer Mice is Associated with Apoptosis and Anti-angiogenesis

The pathogenesis of colorectal cancer (CRC) is associated with gut dysbiosis that is attributed to unhealthy lifestyles and dietary habits. Consumption of microencapsulated probiotics may potentially restore the gut microbiota in favour of prevention against CRC. This study determined the fate of microencapsulated Lactiplantibacillus plantarum (formerly known as Lactobacillus plantarum) LAB12 in the gastrointestinal tract (GIT) and assessed the chemopreventive effect of microencapsulated L. plantarum LAB12 in vivo. The targeted release of L. plantarum LAB12 from Alg-based microcapsules at the stomach, ileum, caecum and colon of Sprague-Dawley rats was examined by confocal microscopy and qPCR. Microcapsules loaded with L. plantarum LAB12 remained intact in the stomach. Free L. plantarum LAB12 were present in abundance (> 7 log CFU) only in the intestines. Subsequently, the chemopreventive properties of microencapsulated L. plantarum LAB12 were validated against NU/NU nude mice bearing orthotopic transplanted CT-26 CRC (12 female mice; 4-6 weeks old; 20-22 g; n = 6/group). Orthotopic mice pre-supplemented with microencapsulated L. plantarum LAB12 (10 log CFU kg-1 BW for 11 weeks) were presented with significantly (p < 0.05) reduced tumour volume (- 98.87%) and weight (- 89.27%) when compared to control. Western blots indicated that the chemopreventive effect could be attributed to apoptosis and anti-angiogenesis mediated, at least in part, through upregulation of tumour suppressor p53 (+ 45.4%) and pro-apoptotic caspase-3 (+ 82.4%), and downregulation of pro-inflammatory COX-2 (- 57.9%), pro-angiogenic VEGF (- 66.8%) and PECAM-1 (-64.1%). Altogether, this study strongly implied the possibility of having L. plantarum LAB12-loaded microcapsules safely incorporated into food and nutraceutical products for prevention against CRC.

Methodological quality of systematic reviews in dentistry including animal studies: a cross-sectional study

BACKGROUND

The overall confidence in the results of systematic reviews including animal models can be heterogeneous. We assessed the methodological quality of systematic reviews including animal models in dentistry as well as the overall confidence in the results of those systematic reviews.

MATERIAL & METHODS

PubMed, Web of Science and Scopus were searched for systematic reviews including animal studies in dentistry published later than January 2010 until 18th of July 2022. Overall confidence in the results was assessed using a modified version of the A MeaSurement Tool to Assess systematic Reviews (AMSTAR-2) checklist. Checklist items were rated as yes, partial yes, no and not applicable. Linear regression analysis was used to investigate associations between systematic review characteristics and the overall adherence to the AMSTAR-2 checklist. The overall confidence in the results was calculated based on the number of critical and non-critical weaknesses presented in the AMSTAR-2 items and rated as high, moderate, low and critical low.

RESULTS

Of initially 951 retrieved systematic reviews, 190 were included in the study. The overall confidence in the results was low in 43 (22.6%) and critically low in 133 (70.0%) systematic reviews. While some AMSTAR-2 items were regularly reported (e.g. conflict of interest, selection in duplicate), others were not (e.g.

FUNDING

n = 1; 0.5%). Multivariable linear regression analysis showed that the adherence scores of AMSTAR-2 was significantly associated with publication year, journal impact factor (IF), topic, and the use of tools to assess risk of bias (RoB) of the systematic reviews.

CONCLUSION

Although the methodological quality of dental systematic reviews of animal models improved over the years, it is still suboptimal. The overall confidence in the results was mostly low or critically low. Systematic reviews, which were published later, published in a journal with a higher IF, focused on non-surgery topics, and used at least one tool to assess RoB correlated with greater adherence to the AMSTAR-2 guidelines.

Evidence-based comparative severity assessment in young and adult mice

In animal-based research, welfare assessments are essential for ethical and legal reasons. However, accurate assessment of suffering in laboratory animals is often complicated by the multidimensional character of distress and pain and the associated affective states. The present study aimed to design and validate multidimensional composite measure schemes comprising behavioral and biochemical parameters based on a bioinformatics approach. Published data sets from induced and genetic mouse models of neurological and psychiatric disorders were subjected to a bioinformatics workflow for cross-model analyses. ROC analyses pointed to a model-specific discriminatory power of selected behavioral parameters. Principal component analyses confirmed that the composite measure schemes developed for adult or young mice provided relevant information with the level of group separation reflecting the expected severity levels. Finally, the validity of the composite measure schemes developed for adult and young mice was further confirmed by k-means-based clustering as a basis for severity classification. The classification systems allowed the allocation of individual animals to different severity levels and a direct comparison of animal groups and other models. In conclusion, the bioinformatics approach confirmed the suitability of the composite measure schemes for evidence-based comparative severity assessment in adult and young mice. In particular, we demonstrated that the composite measure schemes provide a basis for an individualized severity classification in control and experimental groups allowing direct comparison of severity levels across different induced or genetic models. An online tool (R package) is provided, allowing the application of the bioinformatics approach to severity assessment data sets regardless of the parameters or models used. This tool can also be used to validate refinement measures.

Biomimethics: a critical perspective on the ethical implications of biomimetics in technological innovation

Biomimetics, bioinspiration, biomimicry, and related nature-inspired activities-collectively known as biom*-are witnessing an unprecedented surge in popularity, as they offer unparalleled opportunities for technological advancement, innovation, and sustainable development. The growing prevalence of biom*, however, has sparked moral debates regarding their approaches, emphasizing the need for universally applicable ethical guidelines that can effectively guide practitioners in their work. In this perspective, we outline some of the moral, ethical, and legal challenges associated with biom*, particularly the scientific discipline of biomimetics, focusing on various issues surrounding our motivations for pursuing these approaches, the valuation of nature within them, and regulations in the commercialization of biological knowledge. By highlighting the challenges inherent in biom*, this perspective aims to empower practitioners in the field to make informed decisions and take purposeful action. Specific recommendations are provided to guide them in choosing the right course of action for the right reasons.

Discovery of RC-752, a Novel Sigma-1 Receptor Antagonist with Antinociceptive Activity: A Promising Tool for Fighting Neuropathic Pain

Neuropathic pain (NP) is a chronic condition resulting from damaged pain-signaling pathways. It is a debilitating disorder that affects up to 10% of the world's population. Although opioid analgesics are effective in reducing pain, they present severe risks; so, there is a pressing need for non-opioid pain-relieving drugs. One potential alternative is represented by sigma-1 receptor (S1R) antagonists due to their promising analgesic effects. Here, we report the synthesis and biological evaluation of a series of S1R antagonists based on a 2-aryl-4-aminobutanol scaffold. After assessing affinity toward the S1R and selectivity over the sigma-2 receptor (S2R), we evaluated the agonist/antagonist profile of the compounds by investigating their effects on nerve growth factor-induced neurite outgrowth and aquaporin-mediated water permeability in the presence and absence of oxidative stress. (R/S)-RC-752 emerged as the most interesting compound for S1R affinity (K_i S1R = 6.2 ± 0.9) and functional antagonist activity. Furthermore, it showed no cytotoxic effect in two normal human cell lines or in an in vivo zebrafish model and was stable after incubation in mouse plasma. (R/S)-RC-752 was then evaluated in two animal models of NP: the formalin test and the spinal nerve ligation model. The results clearly demonstrated that compound (R/S)-RC-752 effectively alleviated pain in both animal models, thus providing the proof of concept of its efficacy as an antinociceptive agent.

Development of in-vitro pulsatile flow generator for evaluating the performance of hemodialysis catheters

Hemodialysis (HD) using an HD catheter is performed widely on renal failure patients. The catheter was evaluated using the recirculation ratio in pre-clinical status, which is a crucial index indicating its performance. However, pre-clinical in-vivo experiments have limitations: high cost, and ethical issues. Hence, computational and in-vitro methods have been developed as alternatives. However, computational methods require fluid dynamic knowledge, whereas in-vitro experiments are complicated and expensive. In this study, we developed a pulsatile flow generator to mimic blood flow achieving cost effectiveness and user convenience. The device used iterative learning control, achieving blood flow in the superior and inferior vena cava within a 3.3% error. Furthermore, the recirculation ratios were measured based on two insertion directions and two different external pipe materials to evaluate the catheter regarding patients' posture and blood vessel stiffness. The results provide a better understanding of cardiovascular device performance without complicated and costly pre-clinical tests.

Robustness of a multivariate composite score when evaluating distress of animal models for gastrointestinal diseases

The fundament of an evidence-based severity assessment in laboratory animal science is reliable distress parameters. Many readouts are used to evaluate and determine animal distress and the severity of experimental procedures. Therefore, we analyzed four distinct parameters like the body weight, burrowing behavior, nesting, and distress score in the four gastrointestinal animal models (pancreatic ductal adenocarcinoma (PDA), pancreatitis, CCl₄ intoxication, and bile duct ligation (BDL)). Further, we determined the parameters' robustness in various experimental subgroups due to slight variations like drug treatment or telemeter implantations. We used non-parametric bootstrapping to get robust estimates and 95% confidence intervals for the experimental groups. It was found that the performance of the readout parameters is model-dependent and that the distress score is prone to experimental variation. On the other hand, we also found that burrowing and nesting can be more robust than, e.g., the body weight when evaluating PDA. However, the body weight still was highly robust in BDL, pancreatitis, and CCl₄ intoxication. To address the complex nature of the multi-dimensional severity space, we used the Relative Severity Assessment (RELSA) procedure to combine multiple distress parameters into a score and mapped the subgroups and models against a defined reference set obtained by telemeter implantation. This approach allowed us to compare the severity of individual animals in the experimental subgroups using the maximum achieved severity (RELSA_max). With this, the following order of severity was found for the animal models: CCl₄ < PDA ≈ Pancreatitis < BDL. Furthermore, the robustness of the RELSA procedure and outcome was externally validated with a reference set from another laboratory also obtained from telemeter implantation. Since the RELSA procedure reflects the multi-dimensional severity information and is highly robust in estimating the quantitative severity within and between models, it can be deemed a valuable tool for laboratory animal severity assessment.

EFFECT OF DRY EXTRACT FROM REISHI MUSHROOMS ON THE STATE OF ANTIOXIDANT SYSTEM IN RATS WITH DMH-INDUCED COLON CARCINOGENESIS

OBJECTIVE

The aim: To study pro- and antioxidant systems indicators in rats with chemically induced colon carcinogenesis on the background of the reishi mushrooms dry extract use.

PATIENTS AND METHODS

Materials and methods: The study was performed on 120 white male rats. Chronic oncogenic intoxication was modeled by administering 1,2-dimethyl¬hydrazine (DMH) hydrochloride for 30 weeks (1 time per week). A dry extract from the reishi mushrooms was administered intragastrically daily at a dose of 100 mg/kg of the animal's body weight. Blood and liver samples were taken for research monthly. The state of the pro- and antioxidant systems was studied by the content of oxidative modification of proteins products, superoxide dismutase and catalase activity, contents of reduced glutathione and ceruloplasmin.

RESULTS

Results: An increase in the activity of free radical oxidation processes after DMH-induced colon carcinogenesis in rats is evidenced by a decrease in the super-oxide dismutase activity, catalase activity, content of reduced glutathione, an increase in the content of ceruloplasmin and products of oxidative modification of proteins in the blood serum and liver of animals. The effectiveness of the dry extract of reishi mushrooms and its positive effect on the state of pro- and antioxidant systems was experimentally proved.

CONCLUSION

Conclusions: The use of the dry extract of reishi mushrooms under conditions of DMH-induced colon carcinogenesis in rats led to normalization of the anti¬oxidant protection system state and the reduction of oxidative stress.

Behavioral phenotyping of young Scn1a haploinsufficient mice

Dravet syndrome is a rare, severe, infancy-onset epileptic encephalopathy associated with a high premature mortality. In most patients, Dravet syndrome is caused by a heterozygous loss-of-function mutation in the SCN1A gene encoding the alpha 1 subunit of the sodium channel. Of the variety of SCN1A variants identified in patients with Dravet syndrome, SCN1A missense mutations occur in one-third of cases. The novel Scn1a-A1783V mouse model of Dravet syndrome carries the human Ala1783Val missense variant. Recently, the behavioral phenotype of Scn1a-A1783V haploinsufficient adult mice has been characterized, which may provide a valuable basis for assessment of novel therapeutic approaches. However, there is still limited information on the developmental course of behavioral alterations in the Scn1a-A1783V mouse model, which is of particular relevance for conclusions about face validity and severity classification of the model. Based on reference data from young wildtype mice, we analyzed selected behavioral parameters and fecal corticosterone metabolites in the Scn1a-A1783V mouse model during post-weaning development. Differences in the preference for a sweet saccharin solution between Dravet mice and wildtype mice were observed once mice reached sexual maturity. Nest building behavior was already influenced by the Scn1a genotype during prepubescence. Sexually mature Dravet mice showed a significantly reduced burrowing performance as compared to their wildtype littermates. In the open-field test, pronounced hyperactivity and increased thigmotactic behavior were evident in prepubescent and sexually mature Dravet mice. Analysis of Irwin scores revealed several genotype-dependent changes in handling-associated parameters during the course of adolescence. The information obtained provides insight into the age-dependence of behavioral patterns in the novel Scn1a-A1783V mouse model of Dravet syndrome. In addition, the dataset confirms the suitability of the applied behavioral composite measure scheme for evidence-based assessment of cumulative severity in genetic mouse lines.

Human duodenal organoid-derived monolayers serve as a suitable barrier model for duodenal tissue

Usually, duodenal barriers are investigated using intestinal cell lines like Caco-2, which in contrast to native tissue are limited in cell-type representation. Organoids can consist of all intestinal cell types and are supposed to better reflect the in vivo situation. Growing three-dimensionally, with the apical side facing the lumen, application of typical physiological techniques to analyze the barrier is difficult. Organoid-derived monolayers (ODMs) were developed to overcome this. After optimizing culturing conditions, ODMs were characterized and compared to Caco-2 and duodenal tissue. Tight junction composition and appearance were analyzed, and electrophysiological barrier properties, like paracellular and transcellular barrier function and macromolecule permeability, were evaluated. Furthermore, transcriptomic data were analyzed. ODMs had tight junction protein expression and paracellular barrier properties much more resembling the originating tissue than Caco-2. Transcellular barrier was similar between ODMs and native tissue but was increased in Caco-2. Transcriptomic data showed that Caco-2 expressed fewer solute carriers than ODMs and native tissue. In conclusion, while Caco-2 cells differ mostly in transcellular properties, ODMs reflect trans- and paracellular properties of the originating tissue. If cultured under optimized conditions, ODMs possess reproducible functionality, and the variety of different cell types makes them a suitable model for human tissue-specific investigations.

An African ethical perspective on South Africa's regulatory frameworks governing animals in research

In South Africa, there is currently no legislation that addresses animal experimentation directly. There is, however, a complex framework that consists of laws, national standards, and institutional guidelines governing the use of animals in scientific settings. Consequently, this paper starts by unpacking this framework, both legal and voluntary, in the South African context. Thereafter, it examines some criticisms against this framework. It subsequently proposes that an African ethic could respond to these criticisms, and so unpacks the central tenets of an African ethic in order to demonstrate how it may do this. Finally, it will argue that there are convincing moral reasons, from within an African framework, to significantly reduce, and even abolish, the use of animals in research, and that it should be enacted in legal regulations.

Negative psychological aspects of working with experimental animals in scientific research

The aim of the study was to reveal the negative psychological aspects of using animals by scientists and to determine whether the emotional tensions and stress are associated with performing experiments on animals. All 150 participants of the study conduct experiments on animals in their work. Computer-assisted web interviewing, was used to collect the data. Correlation matrices for factorial analysis of main component loads and cluster analysis have been calculated as grouping methods revealed two different categories of researchers, which were mostly distinguished by acceptance and aversion to animal testing and animal welfare. The main findings demonstrated, that there is a group of respondents who feel discomfort when performing experiments on animals. Especially young people involved in animal testing, feel remorse, emotional tension and helplessness.

A non-human primate in vitro functional assay for the early evaluation of TB vaccine candidates

We present a non-human primate mycobacterial growth inhibition assay (MGIA) using in vitro blood or cell co-culture with the aim of refining and expediting early tuberculosis vaccine testing. We have taken steps to optimise the assay using cryopreserved peripheral blood mononuclear cells, transfer it to end-user institutes, and assess technical and biological validity. Increasing cell concentration or mycobacterial input and co-culturing in static 48-well plates compared with rotating tubes improved intra-assay repeatability and sensitivity. Standardisation and harmonisation efforts resulted in high consistency agreements, with repeatability and intermediate precision <10% coefficient of variation (CV) and inter-site reproducibility <20% CV; although some systematic differences were observed. As proof-of-concept, we demonstrated ability to detect a BCG vaccine-induced improvement in growth inhibition in macaque samples, and a correlation between MGIA outcome and measures of protection from in vivo disease development following challenge with either intradermal BCG or aerosol/endobronchial Mycobacterium tuberculosis (M.tb) at a group and individual animal level.

INFLAMMATION AND IMPACT OF VINCRISTINE AND ENTEROSORPTION USE IN CHEMICALLY INDUCED COLON CARCER IN RATS

Background. The increasing incidence of colon malignant tumors is one of the most urgent matters of contemporary medicine. In the study of carcinogenesis of the colon the attention is paid to the state of the body’s immune system and activation of inflammatory processes in experimental animals. Objective. The aim of the study was to estimate the level of markers of inflammation in the serum of experimental animals with chemically induced carcinogenesis and their dynamics in case of administration of the cytostatic Vincristine secondary to AUT-M carbon enterosorbent. Methods. The study was performed on white male rats. Animals were modeled for colon cancer by administration of 1.2-dimethylhydrazine hydrochloride at a dose of 7.2 mg/kg body weight for 30 weeks. AUT-M enterosorbent was administered intragastrically daily during 7 and 21 days after modeling of carcinogenesis at a dose of 1 ml of suspension (corresponding to 0.2 g of drug weight) per 100 g of animal body weight. The antitumor drug was administered to the animals with induced carcinogenesis intragastrically daily during 14 days at a dose of 0.23 mg/kg of body weight after a 21-day detoxification therapy. The activity of inflammatory processes was evaluated by the content of pro-inflammatory interleukin 6 and anti-inflammatory interleukin 4, C-reactive protein in the serum of experimental animals. Results. It was established that introduction of 1.2-dimethylhydrazine hydrochloride in the rats caused changes in the cytokine profile and the content of C-reactive protein. In the affected animals an increase in the content of pro-inflammatory interleukin 6, C-reactive protein, as well as a decrease in the content of anti-inflammatory interleukin 4 was evidenced in all periods of the study. AUT-M enterosorbent contributed to normalization of these parameters. The cytostatic Vincristine had a negligible effect on development of inflammatory processes in the studied animals. Conclusions. In cases of induced carcinogenesis, an imbalance in the content of pro- and anti-inflammatory cytokines, an increase in the content of acute-phase C-reactive protein was established. The positive effect of the cytostatic Vincristine secondary to a previous detoxification therapy with AUТ-M sorbent during a progressive development of inflammatory processes in the presence of modeled carcinogenesis was evidenced.

Experimental research of garden spinach extract as a potential anabolic medicinal product

Disorders of protein metabolism – one of the pathologies, the treatment of which is an urgent problem of modern medicine and pharmacy. The importance of the problem is stipulated due to the prevalence of diseases that are accompanied by a violation of protein metabolism in the body. Restoration of protein resources during such conditions requires adequate intake of structural components from the outside – proteins, amino acids and other biologically active substances-correctors of protein metabolism. In recent decades, much attention has been paid to the discoveries of anabolic agents of natural origin, especially from plants. We conducted research on the study of the anabolic and antioxidant properties of dry extract of spinach garden leaves on the model of food deprivation in rats. Established, that the dry extract at the dose of 100 mg/kg body weight of animals prevents the development of organic disorders of protein metabolism, oxidative stress, prevents a sharp decrease in body weight and slows down the generalized catabolism caused by starvation in rats. Under the influence of the extract on the model of food deprivation, the diuretic function of the kidneys is preserved at the physiological level.

Design of composite measure schemes for comparative severity assessment in animal-based neuroscience research: A case study focussed on rat epilepsy models

Comparative severity assessment of animal models and experimental interventions is of utmost relevance for harm-benefit analysis during ethical evaluation, an animal welfare-based model prioritization as well as the validation of refinement measures. Unfortunately, there is a lack of evidence-based approaches to grade an animal's burden in a sensitive, robust, precise, and objective manner. Particular challenges need to be considered in the context of animal-based neuroscientific research because models of neurological disorders can be characterized by relevant changes in the affective state of an animal. Here, we report about an approach for parameter selection and development of a composite measure scheme designed for precise analysis of the distress of animals in a specific model category. Data sets from the analysis of several behavioral and biochemical parameters in three different epilepsy models were subjected to a principal component analysis to select the most informative parameters. The top-ranking parameters included burrowing, open field locomotion, social interaction, and saccharin preference. These were combined to create a composite measure scheme (CMS). CMS data were subjected to cluster analysis enabling the allocation of severity levels to individual animals. The results provided information for a direct comparison between models indicating a comparable severity of the electrical and chemical post-status epilepticus models, and a lower severity of the kindling model. The new CMS can be directly applied for comparison of other rat models with seizure activity or for assessment of novel refinement approaches in the respective research field. The respective online tool for direct application of the CMS or for creating a new CMS based on other parameters from different models is available at https://github.com/mytalbot/cms. However, the robustness and generalizability needs to be further assessed in future studies. More importantly, our concept of parameter selection can serve as a practice example providing the basis for comparable approaches applicable to the development and validation of CMS for all kinds of disease models or interventions.

Defining Standards in Experimental Microsurgical Training: Recommendations of the European Society for Surgical Research (ESSR) and the International Society for Experimental Microsurgery (ISEM)

Background: Expectations towards surgeons in modern surgical practice are extremely high with minimal complication rates and maximal patient safety as paramount objectives. Both of these aims are highly dependent on individual technical skills that require sustained, focused, and efficient training outside the clinical environment. At the same time, there is an increasing moral and ethical pressure to reduce the use of animals in research and training, which has fundamentally changed the practice of microsurgical training and research. Various animal models were introduced and widely used during the mid-20th century, the pioneering era of experimental microsurgery. Since then, high numbers of ex vivo training concepts and quality control measures have been proposed, all aiming to reduce the number of animals without compromising quality and outcome of training. Summary: Numerous microsurgical training courses are available worldwide, but there is no general agreement concerning the standardization of microsurgical training. The major aim of this literature review and recommendation is to give an overview of various aspects of microsurgical training. We introduce here the findings of a previous survey-based analysis of microsurgical courses within our network. Basic principles behind microsurgical training (3Rs, good laboratory practice, 3Cs), considerations around various microsurgical training models, as well as several skill assessment tools are discussed. Recommendations are formulated following intense discussions within the European Society for Surgical Research (ESSR) and the International Society for Experimental Microsurgery (ISEM), based on scientific literature as well as on several decades of experience in the field of experimental (micro)surgery and preclinical research, represented by the contributing authors. Key Messages: Although ex vivo models are crucial for the replacement and reduction of live animal use, living animals are still indispensable at every level of training which aims at more than just a basic introduction to microsurgical techniques. Modern, competency-based microsurgical training is multi-level, implementing different objective assessment tools as outcome measures. A clear consensus on fundamental principles of microsurgical training and more active international collaboration for the sake of standardization are urgently needed.

Comparison of the protective effects of intratympanic dexamethasone and methylprednisolone against cisplatin-induced ototoxicity

OBJECTIVE

This study aimed to compare the efficacies of intratympanic dexamethasone and methylprednisolone in preventing in cisplatin-induced ototoxicity in rats.

METHODS

Experimental groups of rats (n = 8 each) received intratympanic isotonic saline, intraperitoneal cisplatin and intratympanic isotonic saline, intraperitoneal cisplatin and intratympanic dexamethasone, or intraperitoneal cisplatin and intratympanic methylprednisolone. Distortion product otoacoustic emission thresholds were compared on days 0 and 10 in all rats, and correlations between drug effects and changes in cochlear histology were evaluated.

RESULTS

Distortion product otoacoustic emission thresholds were comparable in groups III and IV (p > 0.05). Significant protection against cisplatin-induced ototoxicity was seen in groups III and IV compared with group II (p < 0.05). Dexamethasone and, to a lesser extent, methylprednisolone protected against cellular apoptosis in cisplatin-induced ototoxicity.

CONCLUSION

Dexamethasone (and possibly methylprednisolone) may be clinically useful as an intratympanic chemopreventive agent to treat cisplatin ototoxicity. Future clinical studies should investigate the use of dexamethasone for this purpose in adult patients.