Posttraumatic stress disorder is characterized by functional dysregulation of dermal fibroblasts.

Incidence of mental health disorders are rising in modernity, with psychological stress linked to a propensity for developing various chronic diseases due to a relative inability of the body to counter the allostatic load on cellular level. Despite these high rates of comorbidities associated with posttraumatic stress disorder (PTSD), there is still a lack of understanding in terms of the peripheral effects of PTSD on tissue level. Therefore, the purpose of this study was to profile basal dermal fibroblast functional status in PTSD using a wide range of markers involved in the cell-to-cell communication facilitated by fibroblasts. Primary dermal fibroblasts derived from patients diagnosed with PTSD (n = 11) and matched trauma exposed controls (i.e. who did not develop PTSD, n = 10) were cultured using standard techniques. The patients and controls were matched based on age, sex, body-mass index (BMI) and lifestyle. The growth rate, population doubling time, surface marker expression (CD31, FNDC5) (flow cytometry), secretome (TIMP-2, MMP-9) (ELISAs), intracellular signalling capacity (Fluo-4 Ca2+ flux) and gene expression (IL-6, IL-10, PTX-3, iNOS, Arg1) were compared between groups. The data illustrated significant PTSD-associated fibroblast conditioning resulting in a blunted signalling capacity. This observation highlights the importance of including tissue-specific investigations in future studies focused on elucidating the association between PTSD and subsequent risk for somatic disease.

Severe Tick-Borne Encephalitis (TBE) in a Patient with X-Linked Agammaglobulinemia; Treatment with TBE Virus IgG Positive Plasma, Clinical Outcome and T Cell Responses.

PURPOSE: A patient with X-linked agammaglobulinemia (XLA) and severe tick-borne encephalitis (TBE) was treated with TBE virus (TBEV) IgG positive plasma. The patient's clinical response, humoral and cellular immune responses were characterized pre- and post-infection. METHODS: ELISA and neutralisation assays were performed on sera and TBEV PCR assay on sera and cerebrospinal fluid. T cell assays were conducted on peripheral blood the patient and five healthy vaccinated controls. RESULTS: The patient was admitted to the hospital with headache and fever. He was not vaccinated against TBE but receiving subcutaneous IgG-replacement therapy (IGRT). TBEV IgG antibodies were low-level positive (due to scIGRT), but the TBEV IgM and TBEV neutralisation tests were negative. During hospitalisation his clinical condition deteriorated (Glasgow coma scale 3/15) and he was treated in the ICU with corticosteroids and external ventricular drainage. He was then treated with plasma containing TBEV IgG without apparent side effects. His symptoms improved within a few days and the TBEV neutralisation test converted to positive. Robust CD8+ T cell responses were observed at three and 18-months post-infection, in the absence of B cells. This was confirmed by tetramers specific for TBEV. CONCLUSION: TBEV IgG-positive plasma given to an XLA patient with TBE without evident adverse reactions may have contributed to a positive clinical outcome. Similar approaches could offer a promising foundation for researching therapeutic options for patients with humoral immunodeficiencies. Importantly, a robust CD8+ T cell response was observed after infection despite the lack of B cells and indicates that these patients can clear acute viral infections and could benefit from future vaccination programs.

An investigation into symptoms of depression and anxiety and emotion regulation among older adolescents from low-income settings in South Africa.

INTRODUCTION: Mental health conditions (MHC) among adolescents in low- and middle-income countries, including South Africa, are estimated to be high. Adaptive emotion regulation (ER) skills can protect against MHC among adolescents. In South Africa, there is limited adolescent mental health prevalence data as well as little understanding of the associations between MHC and ER among adolescents. This study aimed to address these gaps by describing the psychosocial characteristics of older South African adolescents from low-income settings as well as investigating associations between depression and anxiety symptoms and ER. METHODS: We selected 12 schools in collaboration with two NGOs. Learners aged 15-18-years were recruited to complete a tablet-based survey. ER, depression, anxiety, and other psychosocial measures were included. Two multiple linear regression models were used to determine associations between depression symptoms, anxiety symptoms, other psychosocial factors, and ER. RESULTS: Of the 733 participants from 12 Western Cape schools, 417 (56.90%) screened at risk for clinically significant anxiety symptoms, 423 (57.70%) participants for depression symptoms, 229 (31.40%) participants for PTSD symptoms and 263 (35.90%) for risky alcohol use. Depression and anxiety scores were found to be significantly positively correlated with ER difficulties and adolescents struggled most with identifying and utilizing adaptive ER strategies. The adjusted linear regression model reported that female gender, clinically significant depressive, anxiety, post-traumatic stress symptoms and risky-alcohol use were all significantly associated with poorer ER scores, while self-esteem was significantly associated with better ER scores. CONCLUSION: These findings contribute to the South African adolescent mental health literature and to the research gap on the links between depression and anxiety and ER. Future research should consider further exploration of the relationships between psychosocial factors and ER to inform the urgent development and testing of appropriate adolescent interventions in this setting.

Integrative phylogenetic, phylogeographic and morphological characterisation of the Unio crassus species complex reveals cryptic diversity with important conservation implications.

The global decline of freshwater mussels and their crucial ecological services highlight the need to understand their phylogeny, phylogeography and patterns of genetic diversity to guide conservation efforts. Such knowledge is urgently needed for Unio crassus, a highly imperilled species originally widespread throughout Europe and southwest Asia. Recent studies have resurrected several species from synonymy based on mitochondrial data, revealing U. crassus to be a complex of cryptic species. To address long-standing taxonomic uncertainties hindering effective conservation, we integrate morphometric, phylogenetic, and phylogeographic analyses to examine species diversity within the U. crassus complex across its entire range. Phylogenetic analyses were performed using cytochrome c oxidase subunit I (815 specimens from 182 populations) and, for selected specimens, whole mitogenome sequences and Anchored Hybrid Enrichment (AHE) data on âˆ¼ 600 nuclear loci. Mito-nuclear discordance was detected, consistent with mitochondrial DNA gene flow between some species during the Pliocene and Pleistocene. Fossil-calibrated phylogenies based on AHE data support a Mediterranean origin for the U. crassus complex in the Early Miocene. The results of our integrative approach support 12 species in the group: the previously recognised Unio bruguierianus, Unio carneus, Unio crassus, Unio damascensis, Unio ionicus, Unio sesirmensis, and Unio tumidiformis, and the reinstatement of five nominal taxa: Unio desectusstat. rev., Unio gontieriistat. rev., Unio mardinensisstat. rev., Unio nanusstat. rev., and Unio vicariusstat. rev. Morphometric analyses of shell contours reveal important morphospace overlaps among these species, highlighting cryptic, but geographically structured, diversity. The distribution, taxonomy, phylogeography, and conservation of each species are succinctly described.

In BTK, phosphorylated Y223 in the SH3 domain mirrors catalytic activity, but does not influence biological function.

ABSTRACT: Bruton's tyrosine kinase (BTK) is an enzyme needed for B-cell survival, and its inhibitors have become potent targeted medicines for the treatment of B-cell malignancies. The initial activation event of cytoplasmic protein-tyrosine kinases is the phosphorylation of a conserved regulatory tyrosine in the catalytic domain, which in BTK is represented by tyrosine 551. In addition, the tyrosine 223 (Y223) residue in the SRC homology 3 (SH3) domain has, for more than 2 decades, generally been considered necessary for full enzymatic activity. The initial recognition of its potential importance stems from transformation assays using nonlymphoid cells. To determine the biological significance of this residue, we generated CRISPR-Cas-mediated knockin mice carrying a tyrosine to phenylalanine substitution (Y223F), maintaining aromaticity and bulkiness while prohibiting phosphorylation. Using a battery of assays to study leukocyte subsets and the morphology of lymphoid organs, as well as the humoral immune responses, we were unable to detect any difference between wild-type mice and the Y223F mutant. Mice resistant to irreversible BTK inhibitors, through a cysteine 481 to serine substitution (C481S), served as an additional immunization control and mounted similar humoral immune responses as Y223F and wild-type animals. Collectively, our findings suggest that phosphorylation of Y223 serves as a useful proxy for phosphorylation of phospholipase Cγ2 (PLCG2), the endogenous substrate of BTK. However, in contrast to a frequently held conception, this posttranslational modification is dispensable for the function of BTK.

Concurrent use of two dual-combination drenches containing monepantel/abamectin and oxfendazole/levamisole in sheep: effect on marker residues 21 and 28 days after administration.

AIMS: To determine the concentration, in comparison with the maximum residue limit (MRL), of anthelmintic marker residues in the target tissues (liver and fat) of sheep treated concurrently with two oral drenches, one containing monepantel and abamectin and the other oxfendazole and levamisole. METHODS: On day 0 of the study, 12 sheep (six male and six female; 8-9-months old) were dosed according to individual body weight determined the day prior. Zolvix Plus (dual-active oral drench containing 25 g/L monepantel and 2 g/L abamectin) was administered to all animals prior to administration of Scanda (dual-active oral drench containing 80 g/L levamisole hydrochloride and 45.3 g/L oxfendazole). Six sheep (three male and three female) were slaughtered 21 and 28 days after treatment and renal fat and liver samples were collected.Using validated methods, analyses for monepantel sulfone, abamectin, levamisole and oxfendazole (expressed as total fenbendazole sulfone following conversion of the combined concentrations of oxfendazole, fenbendazole and fenbendazole sulfone) were performed on liver samples while renal fat specimens were analysed for monepantel sulfone and abamectin residues only. Detected concentrations were compared to the established MRL in sheep for each analyte determined by the Ministry for Primary Industries. RESULTS: All residues detected in samples of liver and fat collected 21 and 28 days after treatment were below the MRL for each analyte. All liver samples collected on day 21 had detectable monepantel sulfone (mean 232 (min 110, max 388) µg/kg) and oxfendazole (mean 98.7 (min 51.3, max 165) µg/kg) residues below the MRL (5,000 and 500 µg/kg, respectively). Monepantel sulfone (mean 644 (min 242, max 1,119) µg/kg; MRL 7,000 µg/kg) residues were detected in 6/6 renal fat samples. Levamisole residues were detected in 3/6 livers (mean 40.0 (min 14.3, max 78.3) µg/kg; MRL 100 µg/kg), and abamectin residues in 1/6 livers (0.795 µg/kg; MRL 25 µg/kg) and 2/6 fat samples, (mean 0.987 (min 0.514, max 1.46) µg/kg; MRL 50 µg/kg) 21 days after treatment. CONCLUSION AND CLINICAL RELEVANCE: These results suggest that concurrent administration of Zolvix Plus and Scanda to sheep is unlikely to result in an extended residue profile for any of the active ingredients, with all analytes measured being under the approved New Zealand MRL 21 days after treatment. This work was not completed in line with guidance for establishing official residue profiles, nor is it sufficient to propose a new withholding period.

High species homology potentiates quantitative inflammation profiling in zebrafish using immunofluorescence.

Due to substantial homology between the human and zebrafish genome and a high level of conservation of the innate immune system across species, zebrafish larvae have become an invaluable research tool for studying inflammation and modelling inflammatory disease. However, further microscopy techniques need to be developed for better profiling of inflammation and in particular, integrated cytokine responses to different stimuli - approaches are currently largely limited to assessment of changes in cytokine gene transcription and in vivo visualisation using transgenics, which is limited in terms of the number of cytokines that may be assessed at once. In this study, after confirming substantial homology of human vs zebrafish cytokine amino acid sequences, immunofluorescence staining using antibodies directed at human cytokines was performed. Inflammatory cytokine signalling responses to experimental tailfin transection was assessed over 24 h (1 hpi (hours post injury), 2 hpi, 4 hpi, 24 hpi) in zebrafish larvae, with experimental end point at 120 h post fertilization (hpf). When immunofluorescence results were compared to responses observed in rodent and human literature, it is clear that the cytokines follow a similar response, albeit with a condensed total time course. Notably, tumor necrosis factor-α and monocyte chemoattractant protein-1 increased and remained elevated over the 24-h period. In contrast, interleukin-1ß and interleukin-6 peaked at 4 hpi and 2 hpi respectively but had both returned to baseline levels by 24 hpi. Macrophage migration inhibitory factor was lowest at 1 hpi, potentially encouraging macrophage movement into the site of injury, followed by a sharp increase. This protocol provides valuable insight into inflammation over a time course and more so, provides an affordable and accessible method to comprehensively assess inflammation in zebrafish disease models.

Evaluation of Genetic or Cellular Impairments in Type I IFN Immunity in a Cohort of Young Adults with Critical COVID-19.

Several genetic and immunological risk factors for severe COVID-19 have been identified, with monogenic conditions relating to 13 genes of type I interferon (IFN) immunity proposed to explain 4.8% of critical cases. However, previous cohorts have been clinically heterogeneous and were not subjected to thorough genetic and immunological analyses. We therefore aimed to systematically investigate the prevalence of rare genetic variants causing inborn errors of immunity (IEI) and functionally interrogate the type I IFN pathway in young adults that suffered from critical COVID-19 yet lacked comorbidities. We selected and clinically characterized a cohort of 38 previously healthy individuals under 50 years of age who were treated in intensive care units due to critical COVID-19. Blood samples were collected after convalescence. Two patients had IFN-α autoantibodies. Genome sequencing revealed very rare variants in the type I IFN pathway in 31.6% of the patients, which was similar to controls. Analyses of cryopreserved leukocytes did not indicate any defect in plasmacytoid dendritic cell sensing of TLR7 and TLR9 agonists in patients carrying variants in these pathways. However, lymphocyte STAT phosphorylation and protein upregulation upon IFN-α stimulation revealed three possible cases of impaired type I IFN signaling in carriers of rare variants. Together, our results suggest a strategy of functional screening followed by genome analyses and biochemical validation to uncover undiagnosed causes of critical COVID-19.

Memory T cells effectively recognize the SARS-CoV-2 hypermutated BA.2.86 variant.

T cells are critical in mediating the early control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infection. However, it remains unknown whether memory T cells can effectively cross-recognize new SARS-CoV-2 variants with a broad array of mutations, such as the emergent hypermutated BA.2.86 variant. Here, we report in two separate cohorts, including healthy controls and individuals with chronic lymphocytic leukemia, that SARS-CoV-2 spike-specific CD4+ and CD8+ T cells induced by prior infection or vaccination demonstrate resilient immune recognition of BA.2.86. In both cohorts, we found largely preserved SARS-CoV-2 spike-specific CD4+ and CD8+ T cell magnitudes against mutated spike epitopes of BA.2.86. Functional analysis confirmed that both cytokine expression and proliferative capacity of SARS-CoV-2 spike-specific T cells to BA.2.86-mutated spike epitopes are similarly sustained. In summary, our findings indicate that memory CD4+ and CD8+ T cells continue to provide cell-mediated immune recognition to highly mutated emerging variants such as BA.2.86.

Novel Ameloblastin Variants, Contrasting Amelogenesis Imperfecta Phenotypes.

Amelogenesis imperfecta (AI) comprises a group of rare, inherited disorders with abnormal enamel formation. Ameloblastin (AMBN), the second most abundant enamel matrix protein (EMP), plays a critical role in amelogenesis. Pathogenic biallelic loss-of-function AMBN variants are known to cause recessive hypoplastic AI. A report of a family with dominant hypoplastic AI attributed to AMBN missense change p.Pro357Ser, together with data from animal models, suggests that the consequences of AMBN variants in human AI remain incompletely characterized. Here we describe 5 new pathogenic AMBN variants in 11 individuals with AI. These fall within 3 groups by phenotype. Group 1, consisting of 6 families biallelic for combinations of 4 different variants, have yellow hypoplastic AI with poor-quality enamel, consistent with previous reports. Group 2, with 2 families, appears monoallelic for a variant shared with group 1 and has hypomaturation AI of near-normal enamel volume with pitting. Group 3 includes 3 families, all monoallelic for a fifth variant, which are affected by white hypoplastic AI with a thin intact enamel layer. Three variants, c.209C>G; p.(Ser70*) (groups 1 and 2), c.295T>C; p.(Tyr99His) (group 1), and c.76G>A; p.(Ala26Thr) (group 3) were identified in multiple families. Long-read AMBN locus sequencing revealed these variants are on the same conserved haplotype, implying they originate from a common ancestor. Data presented therefore provide further support for possible dominant as well as recessive inheritance for AMBN-related AI and for multiple contrasting phenotypes. In conclusion, our findings suggest pathogenic AMBN variants have a more complex impact on human AI than previously reported.

Effects of atipamezole on selected physiologic parameters in cynomolgus macaques (Macaca fascicularis).

BACKGROUND: Atipamezole, an α-2 adrenergic receptor antagonist, reverses the α-2 agonist anesthetic effects. There is a dearth of information on the physiological effects of these drugs in cynomolgus macaques (Macaca fascicularis). We assessed atipamezole's physiologic effects. We hypothesized atipamezole administration would alter anesthetic parameters. METHODS: Five cynomolgus macaques were sedated with ketamine/dexmedetomidine intramuscularly, followed 45 min later with atipamezole (0.5 mg/kg). Anesthetic parameters (heart rate, blood pressure [systolic (SAP), diastolic (DAP), and mean (MAP) blood pressure], body temperature, respiratory rate, and %SpO2) were monitored prior to and every 10 min (through 60 min) post atipamezole injection. RESULTS: While heart rate was significantly increased for 60 min; SAP, DAP, MAP, and temperature were significantly decreased at 10 min. CONCLUSIONS: This study indicates subcutaneous atipamezole results in increased heart rate and transient blood pressure decrease. These findings are clinically important to ensure anesthetist awareness to properly support and treat patients as needed.

Dolutegravir quantification in wistar rat tissues following chronic administration.

Dolutegravir (DTG) has been introduced into first line combination antiretroviral therapy (ART) for HIV/AIDS. Penetration of ART into HIV reservoirs is essential to prevent continuous replication of HIV. However, accumulation of DTG in HIV reservoirs could be contributing to the adverse effects reported. We have developed and applied liquid chromatography tandem mass spectrometry (LC-MS/MS) methods to quantify DTG in wistar rat biological matrices following chronic DTG administration. DTG was detected using a Shimadzu 8040 triple quadrupole-mass spectrometer. The methods developed were in the concentration ranges of 17.5-8000 ng/mL for plasma and 15.5-16 680 ng/g for tissue matrices. Mean plasma DTG concentrations in the current study closely corresponded to plasma DTG levels reported in humans after chronic treatment. Plasma and tissue DTG concentrations were generally higher in females compared to male wistar rats, but these differences were nullified after correcting for body and organ size. Plasma DTG levels correlated with tissue DTG concentrations in the liver and gastrocnemius muscle tissue. Data suggest that body size - rather than sex - may be a major risk factor determining adverse outcomes of patients on the current DTG dosing strategy which does not account for differences in body mass. Furthermore, plasma DTG was not correlated with adipose tissue DTG concentration. This suggests that adipose may be a primary site for longer term inflammatory dysregulation and adverse outcome following DTG treatment.

"Two Years Later I'm Still Just as Angry": A Focus Group Study of Emergency and Internal Medicine Physicians on Disrespectful Communication.

Phenomenon: Disrespectful behavior between physicians across departments can contribute to burnout, poor learning environments, and adverse patient outcomes. Approach: In this focus group study, we aimed to describe the nature and context of perceived disrespectful communication between emergency and internal medicine physicians (residents and faculty) at patient handoff. We used a constructivist approach and framework method of content analysis to conduct and analyze focus group data from 24 residents and 11 faculty members from May to December 2019 at a large academic medical center. Findings: We organized focus group results into four overarching categories related to disrespectful communication: characteristics and context (including specific phrasing that members from each department interpreted as disrespectful, effects of listener engagement/disengagement, and the tendency for communication that is not in-person to result in misunderstanding and conflict); differences across training levels (with disrespectful communication more likely when participants were at different training levels); the individual correspondent's tendency toward perceived rudeness; and negative/long-term impacts of disrespectful communication on the individual and environment (including avoidance and effects on patient care). Insights: In the context of predominantly positive descriptions of interdepartmental communication, participants described episodes of perceived disrespectful behavior that often had long-lasting, negative impacts on the quality of the learning environment and clinical work. We created a conceptual model illustrating the process and outcomes of these interactions. We make several recommendations to reduce disrespectful communication that can be applied throughout the hospital to potentially improve patient care, interdepartmental collaboration, and trainee and faculty quality of life.

Supporting detection of hostile intentions: automated assistance in a dynamic decision-making context.

In a dynamic decision-making task simulating basic ship movements, participants attempted, through a series of actions, to elicit and identify which one of six other ships was exhibiting either of two hostile behaviors. A high-performing, although imperfect, automated attention aid was introduced. It visually highlighted the ship categorized by an algorithm as the most likely to be hostile. Half of participants also received automation transparency in the form of a statement about why the hostile ship was highlighted. Results indicated that while the aid's advice was often complied with and hence led to higher accuracy with a shorter response time, detection was still suboptimal. Additionally, transparency had limited impacts on all aspects of performance. Implications for detection of hostile intentions and the challenges of supporting dynamic decision making are discussed.

A survey of United States obstetric anesthesiologists' perceived value of obstetric anesthesiology fellowship.

INTRODUCTION: Subspecialty training in obstetric anesthesiology is associated with improved patient outcomes and reduced anesthesia-related morbidity and mortality. Despite this, the demand for fellowship-trained obstetric anesthesiologists far exceeds the supply. This survey study aimed to evaluate the perceived value of obstetric anesthesiology subspecialty training on career trajectory, job satisfaction, quality of life, and job autonomy. METHODS: After Institutional Review Board approval, we conducted a cross-sectional study of fellowship-trained obstetric anesthesiologists in the United States of America. In March and April 2022, program directors of obstetric anesthesiology fellowships distributed an electronic survey link containing 29 multiple-choice questions to their program alumni. Survey content included respondent demographic characteristics, practice models, career information, and perceived value of an obstetric anesthesiology fellowship. RESULTS: We surveyed 217/502 (43%) fellowship-trained obstetric anesthesiologists with a response rate of 158/217 (73%). Most worked in urban, academic, and level IV perinatal health centers. The majority believed an obstetric anesthesiology fellowship was "extremely beneficial" (77%), enhanced quality of life (84%), improved the quality of patient care (99%), and was influential in helping obtain their first post-training job (86%). The perceived value of the fellowship included an enhanced career trajectory, a sense of purpose, improved job satisfaction, a sense of work community, lower burnout, involvement in maternal health initiatives, increased mentorship, and departmental leadership. CONCLUSION: In this survey study, fellowship-trained obstetric anesthesiologists perceived a positive impact of fellowship training on career trajectory, job protection and autonomy, quality of life, and job satisfaction. This information may be meaningful to trainees considering pursuing a fellowship and a career in obstetric anesthesiology.

Measuring tissue water potential in marine macroalgae via an updated Chardakov method.

Regulation of tissue water potential is a key mechanism in macroalgal osmotic responses to changing external osmotic conditions, which are common in tidally influenced estuarine and intertidal systems. Nevertheless, significant knowledge gaps exist in our understanding of osmotic responses in macroalgae because few methods measure osmotic potential within macroalgal tissues. Leaf psychrometers have furthered understanding of osmotic potentials in terrestrial plant water relations, yet these have not been developed to measure the range of highly negative potential values found in marine macroalgae. To address these gaps, we present an effective, updated version of the Chardakov method to measure tissue water potential in macroalgae. Here, we present a case study examining macroalgal response in tissue water potential by two morphologically and evolutionarily distinct species, Ulva lactuca (Chlorophyta) and Hypnea musciformis (Rhodophyta) to four paired salinity and nutrient treatments at two temperatures. These treatments simulate a gradient from full coastal ocean conditions to brackish submarine groundwater discharge, an ecosystem type found on basaltic shorelines. Both algae demonstrated plasticity in osmotic response to submarine groundwater discharge with significant positive correlations between tissue water potential and proportion of submarine groundwater discharge in the treatment. These results are the first to describe macroalgal response in tissue water potential, a first step to understanding algal physiological ecology in such complex coastal environments. This revised Chardakov method is a valuable tool to better understand species-specific osmotic responses to ecologically relevant conditions, and can augment the study of other tidal systems and ontogenetic stages.

Efficacy and safety of three different opioid-based immobilisation combinations in blesbok (Damaliscus pygargus phillipsi).

African wildlife species are increasingly being immobilised with combinations of a low dose of potent opioids combined with medetomidine and azaperone. The physiological effects of these combinations in comparison to conventional potent opioidazaperone combinations have scarcely been evaluated. In this cross-over study conducted on eight captive blesbok, we compared the physiological variables of blesbok immobilised with 2 mg of thiafentanil + 10 mg of azaperone (TA); 0.5 mg thiafentanil + 1.5 mg medetomidine (TM), and 0.5 mg thiafentanil + 1.5. mg medetomidine + 10 mg azaperone (TMA). Thiafentanil's effects were antagonised with naltrexone at 10 mg naltrexone per mg thiafentanil, and the medetomidine effects with atipamezole at 5 mg atipamezole per mg medetomidine. The physiological variables were compared between treatment groups using descriptive statistics and repeated measures ANOVA. The TA combination resulted in the shortest induction and recovery times, higher heart rates, respiratory rates, PaO2, SpO2, and lower MAP and A-a gradients, but with less muscle relaxation. The TM and TMA combinations caused marked bradycardia and hypoxaemia. The hypoxaemia was most severe in animals immobilised with TMA, and four of eight blesbok immobilised had a PaO2 < 35 mmHg at the 10- or 15-minute sampling point. These blesbok were provided supplementary oxygen, which corrected the hypoxaemia. The TA combinations caused the lowest degree of physiological compromise. All three combinations were effective for the immobilisation of blesbok, but as the low-dose thiafentanil and high-dose medetomidine combinations caused marked hypoxaemia, supplementary oxygen is recommended when using these combinations.