Intramuscular Research Articles

A novel cortical biomarker signature predicts individual pain sensitivity.

Biomarkers would greatly assist chronic pain management. The present study aimed to undertake analytical validation of a sensorimotor cortical biomarker signature for pain consisting of two measures: sensorimotor peak alpha frequency (PAF) and corticomotor excitability (CME), using a human model of prolonged temporomandibular pain (masseter intramuscular injection of nerve growth factor [NGF]). 150 participants received an injection of NGF to the right masseter muscle on Days 0 and 2, inducing prolonged pain lasting up to 4 weeks. Electroencephalography (EEG) to assess PAF and transcranial magnetic stimulation (TMS) to assess CME were recorded on Days 0, 2 and 5. We determined the predictive accuracy of the PAF/CME biomarker signature using a nested control-test scheme: machine learning models were run on a training set (n = 100), where PAF and CME were predictors and pain sensitivity was the outcome. The winning classifier was assessed on a test set (n = 50) comparing the predicted pain labels against the true labels. The winning classifier was logistic regression, with an outstanding area under the curve (AUC=1.00). The locked model assessed on the test set had excellent performance (AUC=0.88). Results were reproduced across a range of methodological parameters. Moreover, inclusion of sex and pain catastrophizing as covariates did not improve model performance, suggesting the model including biomarkers only was more robust. PAF and CME biomarkers showed good-excellent test-retest reliability. This study provides evidence for a sensorimotor cortical biomarker signature for pain sensitivity. The combination of accuracy, reproducibility, and reliability, suggests the PAF/CME biomarker signature has substantial potential for clinical translation.

Development of a recombinant Lactobacillus plantarum oral vaccine expressing VP2 protein for preventing feline panleukopenia virus

Feline panleukopenia virus (FPV) represents a significant health threat to the kittens. While traditional vaccines administered via subcutaneous or intramuscular injection are effective, they can induce stress and adverse reactions. Moreover, unvaccinated kittens visiting veterinary clinics risk exposure to FPV, increasing their susceptibility to infection. Therefore, there is an urgent need for a safer, more gentle vaccination method with streamlined administration. In this study, we developed a recombinant L. plantarum NC8/VP2 expressing the VP2 protein of the prevalent Chinese FPV strain, FPV-251. Our results show that L. plantarum NC8/VP2 effectively colonizes the feline intestinal tract and induces high levels of neutralizing antibodies through oral administration. Kittens exhibited significant protection against FPV-251 infection and associated illnesses or fatalities after 30 days of continuous dosing. These results highlight the potential of recombinant L. plantarum NC8/VP2 as a novel oral vaccine for FPV, presenting a promising approach for disease prevention in domestic cats.

Evaluation of the Deletion of African Swine Fever Virus E111R Gene from the Georgia Isolate in Virus Replication and Virulence in Domestic Pigs.

African swine fever virus (ASFV) is the causative agent of an often lethal disease in domestic pigs, African swine fever (ASF). ASF is currently a pandemic disease challenging pig production in Eurasia. While the ASFV genome encodes for over 160 proteins, the function of most of them are still not characterized. Among those ASF genes with unknown functions is the E111R gene. It has been recently reported that the deletion of the E111R gene from the genome of the virulent Chinese field isolate SY18 strain produced a reduction of virus virulence when pigs were inoculated at relatively low doses. Conversely, we report here that deletion of the ASFV gene E111R in the Georgia 2010 isolate does not alter the virulence of the parental virus in experimentally inoculated pigs. A recombinant virus lacking the E111R gene, ASFV-G-∆E111R was intramuscularly (IM) inoculated in domestic pigs at a dose of 102 HAD50 of ASFV-G-∆E111R and compared with animals that received a similar dose of virulent ASFV-G. Both, animals inoculated with either the recombinant ASFV-G-∆E111R or the parental virus developed a fatal form of the disease and were euthanized around the 6th-7th day post-inoculation (dpi).

Safety and immunogenicity after a 30-month boost of a subtype C ALVAC-HIV (vCP2438) vaccine prime plus bivalent subtype C gp120/MF59 vaccine boost (HVTN 100): A phase 1–2 randomized double-blind placebo-controlled trial

Induction of broad, durable immune responses is a challenge in HIV vaccine development. HVTN 100 Part A administered subtype C-containing ALVAC-HIV at months 0 and 1, and ALVAC-HIV with bivalent subtype C gp120/MF59 at months 3, 6 and 12. As IgG binding antibody and T-cell responses were similar or greater at month 12.5 vs. month 6.5, but waned by month 18, we investigated vaccine-elicited immune responses after a month 30 boost in this study, HVTN 100 Part B. From 13 September 2017 to 7 August 2018, a subgroup of vaccinees was randomized to receive intramuscular injections of ALVAC+gp120/MF59 (n = 32) or gp120/MF59 alone (n = 31) and a subgroup of placebo recipients was administered placebo (n = 7) at month 30. Primary outcomes were safety, IgG binding antibodies (bAbs) to vaccine-specific and V1V2 Env proteins and vaccine-specific CD4+ T cells at month 30.5. Secondary outcomes included neutralizing and antibody dependent cellular cytotoxicity functions and durability at months 30 and 36. Both vaccine groups had an acceptable safety profile. There were no statistically significant differences in the occurrence or level of IgG bAbs between the vaccine boost groups for any vaccine-specific or V1V2 antigens. IgG responses were higher to vaccine-matched gp120 than to V1V2. The booster vaccination restored the magnitude-breadth IgG bAb response to V1V2 antigens at month 30.5. However, it rapidly waned by month 36. CD4+ T-cell response rates to the 3 vaccine-matched Env antigens for the combined vaccine groups ranged from 37% at month 30, boosted to as high as 91% at month 30.5, and waned by month 36 to as low as 44%, with no significant differences between the vaccine boost groups. Because these responses waned after 6 months, additional strategies may be needed to maintain the durability of prime-boost vaccine regimens and to generate these or other immune responses that confer protection. Trial registration: South African National Clinical Trials Register (SANCTR number: DOH—27-0215-4796) and ClinicalTrials.gov (NCT02404311).

Blood Distribution of SARS-CoV-2 Lipid Nanoparticle mRNA Vaccine in Humans.

Lipid nanoparticle mRNA vaccines are an exciting but emerging technology used in humans. There is limited understanding of the factors that influence their biodistribution and immunogenicity. Antibodies to poly(ethylene glycol) (PEG), which is on the surface of the lipid nanoparticle, are detectable in humans and boosted by human mRNA vaccination. We hypothesized that PEG-specific antibodies could increase the clearance of mRNA vaccines. To test this, we developed methods to quantify both the vaccine mRNA and ionizable lipid in frequent serial blood samples from 19 subjects receiving Moderna SPIKEVAX mRNA booster immunization. Both the vaccine mRNA and ionizable lipid peaked in blood 1-2 days post vaccination (median peak level 0.19 and 3.22 ng mL-1, respectively). The vaccine mRNA was detectable and quantifiable up to 14-15 days postvaccination in 37% of subjects. We measured the proportion of vaccine mRNA that was relatively intact in blood over time and found that the decay kinetics of the intact mRNA and ionizable lipid were identical, suggesting the intact lipid nanoparticle recirculates in blood. However, the decay rates of mRNA and ionizable lipids did not correlate with baseline levels of PEG-specific antibodies. Interestingly, the magnitude of mRNA and ionizable lipid detected in blood did correlate with the boost in the level of PEG antibodies. Furthermore, the ability of a subject's monocytes to phagocytose lipid nanoparticles was inversely related to the rise in PEG antibodies. This suggests that the circulation of mRNA lipid nanoparticles into the blood and their clearance by phagocytes influence the PEG immunogenicity of the mRNA vaccines. Overall, this work defines the pharmacokinetics of lipid nanoparticle mRNA vaccine components in human blood after intramuscular injection and the factors that influence these processes. These insights should be valuable in improving the future safety and efficacy of lipid nanoparticle mRNA vaccines and therapeutics.

Impact of hepatitis B immunoglobulin mode of administration on treatment experiences of patients after liver transplantation: Results from an online survey.

Hepatitis B immunoglobulin (HBIG) in combination with a potent nucleos(t)ide analog is considered the standard of care for prophylaxis against hepatitis B virus (HBV) reinfection after liver transplantation for HBV-associated disease. To evaluate patients' satisfaction, preferences, and requirements for subcutaneous (SC), intramuscular (IM), and intravenous (IV) HBIG treatments. A self-completion, cross-sectional, online, 22-question survey was conducted to examine perceptions and satisfaction with current HBIG treatment in adults receiving HBIG treatment following liver transplantation for HBV-associated disease in France, Italy, and Turkey. Hypothetical HBIG products with different administration modes were evaluated using target product profile assessment and a conjoint (trade-off) exercise. Ninety patients were enrolled; 32%, 17%, and 51% were SC, IM, and IV HBIG users, respectively. Mean duration of treatment was 36.2 months. SC HBIG had the least negative impact on emotional well-being and social life and was perceived as the most convenient, easiest to administer, least painful, and had the highest self-rating of treatment compliance. More IM HBIG users than SC or IV HBIG users reported that administration frequency was excessive (67%, 28%, and 28%, respectively). In the target product profile assessment, 76% of patients were likely to use hypothetical SC HBIG. In the conjoint exercise, administration route, frequency, and duration were key drivers of treatment preferences. Ease, frequency, duration, and side effects of HBIG treatment administration were key drivers of treatment preferences, and SC HBIG appeared advantageous over IM and IV HBIG for administration ease, convenience, and pain. A hypothetical SC HBIG product elicited a favorable response. Patient demographics, personal preferences, and satisfaction with HBIG treatment modalities may influence long-term treatment compliance.

A call for compassionate opioid overdose response

High dose and long-acting opioid overdose reversal drugs can precipitate withdrawal in people who are opioid dependent. Products recently brought to market for community use in the United States (US) have drawn international concern because of their increased risk of withdrawal. At the March 18–19, 2024, Compassionate Overdose Response Summit & Naloxone Dosing Meeting, a panel of harm reduction experts issued the following call to action: 1) people who use drugs should be directly involved in decisions regarding the research, development, selection, and distribution of opioid overdose reversal products; 2) regulatory agencies and pharmaceutical manufacturers should carefully consider and communicate the risk and duration of withdrawal associated with higher dose and longer-acting opioid antagonists; 3) take-home naloxone kits should include at least two doses of an intramuscular (IM) product containing 0.4 mg or an intranasal (IN) product containing ≤4 mg; 4) At this time, high dose and long-acting opioid antagonists have no use in acute opioid overdose response; and, 5) overdose response educational materials, instructions on overdose response, and training should emphasize the restoration of breathing, avoiding withdrawal, and compassionate post-overdose support and care. High dose and long-acting opioid overdose reversal drugs were approved without testing for withdrawal and are often aggressively marketed despite decades of evidence from naloxone distribution programs worldwide that the ideal dose of naloxone is one that restores breathing without inducing withdrawal. Government agencies should direct resources to harm reduction programs to make standard dose take-home naloxone products widely available among people who use drugs. Lay bystanders, people who use drugs, their families, and professional first responders can learn and apply a compassionate approach to opioid overdose response.

Safety of intramuscular tixagevimab-cilgavimab (Evusheld®) administration in patients at risk of iatrogenic haematoma due to haematological disorders.

Traditionally, intramuscular (IM) injections have been avoided in patients with haematological diseases due to the risk of iatrogenic haematoma. Tixagevimab-cilgavimab (Evusheld®) is a novel monoclonal antibody combination used as preexposure prophylaxis against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), for those at highest risk of severe infections. It is delivered as two separate IM injections (1.5 mL each). Patients with haematological disease are at higher risk for severe SARS-CoV-2 infections, which may be partially abrogated by the prophylactic inoculation of tixagevimab-cilgavimab. A combined retrospective and prospective study of patients under the haematology service at a large metropolitan hospital receiving tixagevimab-cilgavimab was conducted. Tixagevimab-cilgavimab was administered IM to all patients, with platelet and factor replacement provided according to local protocols. Patients completed a numerical pain score daily for seven days following the injection, with scores ≥4/10 prompting an ultrasound to identify iatrogenic gluteal haematomas. The study recruited 131 patients; 66 patients were thrombocytopenic, including 10 patients with a platelet count <30 × 109/L. Fourteen patients (10.7%) received a single platelet transfusion prior to tixagevimab-cilgavimab administration, while two patients received fresh frozen plasma. No gluteal haematomas were identified, and only two patients reported an initial pain score of ≥4/10. The intramuscular administration of tixagevimab-cilgavimab in patients with haematological diseases was well tolerated and was not associated with iatrogenic haematoma.

Berberine Targets PKM2 to Activate the t-PA-Induced Fibrinolytic System and Improves Thrombosis.

Arterial thrombosis, a condition in which thrombi form in arteries, can lead to various acute cardiovascular diseases and impact the quality of life and survival of patients. Berberine (BBR), a quaternary ammonium alkaloid, has been shown to treat these diseases. However, further exploration is needed to understand underlying mechanisms of BBR. Rats were administered BBR via intramuscular injection. Then, an FeCl3-coated filter paper was applied to a carotid artery to induce thrombosis. The size of the thrombus and the blood flow velocity were evaluated by carotid ultrasound. The shape of the thrombus was observed using staining and microscopy. The expression levels of mRNA and proteins were verified. Additionally, mass spectrometry and single-cell RNA sequencing analysis were conducted. The administration of BBR resulted in a significant reduction in the thrombus area and an extension of the thrombus-clogging time. Furthermore, BBR administration effectively reversed the decreasing tissue-plasminogen activator (t-PA) expression and alterations in fibrinolysis system of model group. Additionally, the expression of PKM2 was suppressed following BBR administration, and the overexpression of PKM2 inhibited t-PA expression. BBR ameliorates thrombosis by modulating expression of PKM2, subsequently impacting the expression of t-PA within fibrinolytic system. These preliminary findings suggest that BBR could be a potential preventive and therapeutic strategy for arterial thromboembolic diseases.

Real-world data on long-acting intramuscular maintenance therapy with cabotegravir and rilpivirine mirror Phase 3 results.

Cabotegravir, an integrase strand transfer inhibitor, and rilpivirine, an NNRTI, constitute the first long-acting (LA), injectable, two-drug ART regimen approved for the maintenance of virological suppression in persons living with HIV-1 (PLHIV). The aim of this study was to assess clinical effectiveness and tolerability of LA cabotegravir/rilpivirine in a real-world setting. We conducted a retrospective, single centre study, including all PLHIV receiving LA cabotegravir/rilpivirine as standard-of-care in our tertiary centre even if initiated in clinical trials. Between 2014 and 2022, 126 PLHIV initiated LA cabotegravir/rilpivirine. All were ART-experienced, and 98.4% had a viral load (VL) of <50 copies/mL before LA cabotegravir/rilpivirine initiation. Median BMI at cabotegravir/rilpivirine initiation was 24 IQR (23-28). During a median follow-up of 9 months IQR (7-24), 27 patients discontinued cabotegravir/rilpivirine because of virological failure, 6 for adverse events, 11 for personal reasons unrelated to treatment tolerance and 5 for other reasons. Virological failure was not associated with a higher BMI, nor with weight gain during LA intramuscular (IM) cabotegravir/rilpivirine treatment, inadequate cabotegravir and rilpivirine concentrations, VL blips or the use of oral lead-in (OLI) or not. No drug resistance-associated mutation emerged. Adverse events leading to treatment interruption were injection-site pain (n = 3) and neuropsychological side effects (n = 3). A correlation between BMI and both cabotegravir and rilpivirine concentrations at 1 month post-initiation of LA-IM cabotegravir/rilpivirine was observed, with no impact of OLI. Data from this real-world cohort of PLHIV who received cabotegravir/rilpivirine LA injections suggest that this regimen is effective and well tolerated. Virological failures were not associated with the acquisition of resistance mutations.

A Retrospective Study on Botulinum Toxin Injection in Patients With Multiple Sclerosis Related Tremor: A Treatment Option Worth Trying

Objectives Multiple sclerosis (MS)-related tremor remains a disabling problem that often responds poorly to medical treatments. This study aims to evaluate the effect of botulinum toxin type A on MS-related upper limb tremor. Methods This retrospective observational cohort study included 8 patients who received intramuscular injections of onabotulinum toxin type A for medically refractory MS-related tremor. Hospital records before and 4–6 weeks after treatment, including the Fahn-Tolosa-Marin Tremor rating scale (FTM-TRS), electrophysiological tremor analysis, neurological examination findings, and videos, were reviewed retrospectively. Results There was significant improvement after botulinum toxin injection in the FTM TRS part A score for tremor (P = 0.011), FTM TRS part B score for hand function (P = 0.011), FTM Part score for activities of daily living (P = 0.012), and FTM TRS total score for overall evaluation (P = 0.012). Electrophysiological tremor analysis revealed maximal tremor amplitudes between 700–2000 μV (before treatment) and between 300–1000 μV (after treatment). The mean tremor amplitudes before and after treatment were 1350 μV and 725 μV, respectively. No adverse reactions were observed after botulinum toxin treatment. Conclusions BoNT may improve upper limb tremor and functionality in MS-related tremor. The treatment involved administering BoNT under EMG guidance, with careful muscle selection based on clinical assessment and EMG findings. This approach aimed to optimize treatment efficacy while minimizing potential adverse effects. Further studies are warranted to confirm these findings.

Adrenal crisis precipitated by omission of regular intramuscular depo-medrone injections: the importance of counselling for adrenal insufficiency in rheumatology patients on long term exogenous steroids

Adrenal crisis precipitated by omission of regular intramuscular depo-medrone injections: the importance of counselling for adrenal insufficiency in rheumatology patients on long term exogenous steroids

Pharmacokinetics and Plasma Protein Binding of Flunixin in Rainbow Trout (Oncorhynchus mykiss).

Flunixin's pharmacokinetics, bioavailability, and plasma protein binding were examined in rainbow trout. The experiment involved 252 rainbow trout (Oncorhynchus mykiss) maintained at 12 ± 0.6°C. Flunixin was administered to rainbow trout via intravascular (IV), intramuscular (IM), and oral routes at a dosage of 2.2 mg/kg. Plasma samples were collected at times 0 (control), 0.25, 0.5, 1, 2, 4, 6, 8, 10, 12, 24, 48, 72, and 96 h. High-pressure liquid chromatography-ultraviolet was employed to quantify flunixin concentrations. The elimination half-life (t1/2ʎz) for flunixin was 8.37 h for IV, 8.68 h for IM, and 8.76 h for oral. The t1/2ʎz was similar between administration groups. The volume of distribution at a steady state and total body clearance were 55.81 mL/kg and 6.83 mL/h/kg, respectively, after IV administration. The mean peak plasma concentration was 6.24 ± 0.41 μg/mL at 4 h for oral administration and 13.98 ± 0.86 μg/mL at 2 h for IM administration. The invitro protein binding ratio of flunixin in rainbow trout plasma was 96.34 ± 2.29%. The bioavailability of flunixin after oral (25.74%) administration was lower than that after IM (66.70%) administration. Thus, developing an oral pharmaceutical formulation that can be administered with feed and has high bioavailability could enhance the therapeutic effect.

Effectiveness Of Local Cold Application, Manual Pressure, Shot Blocker And Standard Injection Procedure During Tetanus Diphtheria (Td) Vaccine Booster Immunization In Reducing Pain At The Intramuscular Injection Site Of Children Studying In Selected Schools: A Systematic Review

Effectiveness Of Local Cold Application, Manual Pressure, Shot Blocker And Standard Injection Procedure During Tetanus Diphtheria (Td) Vaccine Booster Immunization In Reducing Pain At The Intramuscular Injection Site Of Children Studying In Selected Schools: A Systematic Review

An effective vaccine against influenza A virus based on the matrix protein 2 (M2)

The ever-increasing antigenic diversity of the hemagglutinin (HA) of influenza A virus (IAV) poses a significant challenge for effective vaccine development. Notably, the matrix protein 2 (M2) is a highly conserved 97 amino acid long transmembrane tetrameric protein present in the envelope of IAV. More than 99 % of IAV strains circulating in American swine herds share the identical pandemic (pdm) isoform of M2, making it an ideal target antigen for a vaccine that could elicit broadly protective immunity. Here, using soluble nanoscale membrane assemblies termed nanodiscs (NDs), we designed this membrane mimetic nanostructures displaying full-length M2 in its natural transmembrane configuration (M2ND). Intramuscular (IM) immunization of swine with M2ND mixed with conventional emulsion adjuvant elicited M2-specific IgG antibodies in the serum that recognized influenza virions and M2-specific interferon-γ secreting cells present in the blood. Intranasal (IN) immunization with M2ND adjuvanted with a mycobacterial extract elicited M2-specific IgA in mucosal secretions that also recognized IAV. Immunization with an influenza whole inactivated virus (WIV) vaccine supplemented with a concurrent IM injection of M2ND mixed with an emulsion adjuvant increased the level of protective immunity afforded by the former against a challenge with an antigenically distinct H3N2 IAV, as exhibited by an enhanced elimination of virus from the lung. The lone IM administration of the M2ND vaccine mixed with an emulsion adjuvant provided measurable protection as evidenced by a >10-fold reduction or complete elimination of the challenge virus from the lung, but it did not diminish the viral load in nasal secretions nor the extent of pneumonia that ensued after the virus challenge. In contrast, an improved formulation of the M2ND vaccine that incorporated synthetic CpG oligodeoxynucleotides (CpG-ODN) in the nanostructures administered alone, via the IN and IM routes combined, provided a significant level of protective immunity against IAV as evidenced by a decreased viral load in both the upper and lower respiratory tracts and fully eliminated the occurrence of pneumonia in 89 % of the pigs immunized with this biologic. Notably, to be effective, the M2 protein must be displayed in the ND assemblies, as shown by the observation that simply mixing M2 with empty NDs incorporating CpG-ODN (eND-CpG-ODN) did not provide protective immunity. This novel M2-based vaccine offers great promise to help increase the breadth of protection afforded by conventional WIV vaccines against the diversity of IAV in circulation and, plausibly, as a broadly protective stand-alone biologic.

Development of a novel intramuscular liposomal injection for advanced meloxicam delivery: Preparation, characterization, in vivo pharmacokinetics, pharmacodynamics, and pain assessment in an orthopedic pain model

Pain produces several physiological, and degenerative complications. This study aimed to formulate meloxicam (MLX) in liposomes to increase solubility and deliver MLX in a controlled manner to overcome its poor aqueous solubility and relatively short t1/2 problems. Liposomes were prepared by thin film hydration followed by ultrasonication. Tests for characterizing formulations included particle size, span, entrapment efficiency, drug loading, stability, differential scanning calorimetry (DSC), Fourier transformation infrared (FT-IR) spectroscopy, morphology, in vitro release, release kinetics mathematical modeling, and an in vivo pain model in dogs undergoing orthopedic surgeries, followed by in vivo pharmacokinetics, pharmacodynamics, and pain assessment studies in comparison to the reference standard, Mobitil®. Liposomal MLX had a particle size of around 100 nm, 82 % entrapment efficiency, and 4.62 % drug loading. Stability studies, DSC, and FT-IR spectroscopy indicated that liposomes were highly stable. The formulation showed an improved in vitro controlled release pattern and an enhanced in vivo pharmacokinetic behavior as manifested by higher t1/2 and AUC0–24 and lower Cl/F in comparison to Mobitil®. The pharmacodynamics study and pain scales demonstrated liposomal MLX managed postoperative pain better than Mobitil®. In conclusion, the incorporation of MLX in liposomes increased its solubility and stability, as well as its pain management properties.

PSLBII-17 Supplementation with organic versus inorganic selenium during pregnancy to support ewe and lamb health

Abstract Selenium (Se) is essential for optimal ovine health and production, and sheep raised on Se-deficient soils can be vulnerable to Se deficiencies that can affect immune function. Organic or inorganic forms of Se supplementation can remedy these consequences. While inorganic Se is less costly, organic Se is more bioavailable and may be more efficient in providing Se to ewes and lambs. The objectives of this study were to determine how organic versus inorganic Se supplementation affects ewe Se status, Se transfer from ewes to lambs, and the antibody-mediated immune response and dermal hypersensitivity response (DHR) of ewes and their lambs. Dorset-Rideau ewes (n = 100) were enrolled in a randomized complete block design study. From gestation d (gd) 110 to postpartum d (ppd) 50, ewes were fed either a Se-deficient diet and supplemented with no Se, 0.3 mg inorganic Se, or 0.3 mg or 0.6 mg organic Se. Sera were collected on gd 110, 130, 140, and ppd 10 and 50 to determine ewe Se status. On gd 110 and 120, ewes received an intramuscular injection of 0.5 mg ovalbumin (OVA) antigen, and on gd 130 the DHR to OVA was assessed by measuring change in skinfold thickness 0, 6, 24 and 48 h post intradermal injection. To measure the transfer of Se from ewe to lamb, a subset of lambs was euthanized at ppd 10, and longissimus dorsi muscle samples were collected and analyzed for Se content. On ppd 20 and 30, lambs received an intramuscular injection of 0.5 mg hen egg white lysozyme (HEWL) antigen, and on ppd 40 the DHR to HEWL was assessed using the aforementioned protocol. Analysis of ewe sera showed a positive correlation between organic Se supplementation and greater Se concentrations (P &amp;lt; 0.01). Moreover, statistical analyses of the DHR results using a generalized least squares linear model (RStudio) indicate that Se supplementation increased the immune response compared with the non-supplemented ewes (P &amp;lt; 0.01). However, no significant differences between organic and inorganic Se supplementation were found. In lambs, greater ewe Se supplementation resulted in greater Se muscle content (P &amp;gt; 0.01). and organic Se supplementation to ewes significantly increased lamb Se muscle content compared with inorganic Se supplementation (P &amp;gt; 0.01). Finally, analyses of the lamb DHR showed that maternal organic Se supplementation improved the lamb immune response compared with the control group (P &amp;gt; 0.05). Therefore, organic Se supplementation optimally enhances ewe and lamb Se status and their adaptive immune response compared with the inorganic and control groups. This knowledge will guide optimal ewe Se-supplementation choices during pregnancy and postpartum, thus promoting lamb and ewe health.

PSV-4 Clodronate re-release in response to controlled exercise and bone stressors in juvenile horses

Abstract Concerns over the extra-label use of bisphosphonates in skeletally immature horses has extended to include its likely re-release from bone into circulation in response to stressors. Therefore, the objective of this study was to be first to quantify the re-release of clodronate in response to controlled stressors. Yearling Quarter horses (n = 32) were stratified by age, body weight (BW), sex, and initial bone optical density into four treatment groups for a 168-d trial. Treatments consisted of control (CON; n = 8), single-dose (1X; d 84; n = 8), 2-dose (2X; d 0 and 84; n = 8), and four-dose groups (4X; d 0, 42, 84, and 126; n = 8). All horses received iso-volumetric intramuscular injections of either 1.8 mg/kg BW clodronate disodium (OSPHOSÒ) or saline (placebo) on d 0, 42, 84, and 126. Horses were housed in individual stalls (3.6 m × 7.2 m). Diets were formulated to meet nutrient requirements including concentrate offered every 12-h and ad libitum coastal bermudagrass (Cynodon dactylon) hay and water. Horses were exercised 5 d/wk with a progressive workload, and maximum exercise intensity was reached on d 120, verified via heart rate and blood lactate. On d 120, blood samples were collected prior to the start of the exercise bout (pre), and 0-, 0.5-, 1-, 3-, 12-, and 24-h post exercise. Both tuber coxae of each horse were biopsied on d 168 with blood samples collected prior to (pre), and 0, 12, 24, 48, 72, 168, and 336 h post biopsy. Clodronate was quantified in plasma from exercise and biopsy samples using liquid chromatography tandem mass spectrometry. Exercise and biopsy serum were analyzed for cortisol, a marker of stress, while biopsy serum was analyzed for substance P, a pain marker. Data were analyzed using SAS PROC MIXED. Exercise did not result in clodronate re-release as there was no treatment x time interaction or time effect (P ≥ 0.44), but clodronate was dose-dependently greater in treated groups throughout the exercise collection period (P &amp;lt; 0.01). A treatment x time interaction (P ≤ 0.01) was observed for clodronate concentrations surrounding bone biopsy in which concentrations decreased at 168 h post biopsy before increasing at 336 h in 4X horses. Substance P increased over time (P &amp;lt; 0.01) following biopsy, regardless of treatment. Despite decreasing over time (P ≤ 0.01), there were similarly no treatment differences (P ≥ 0.46) nor treatment ´ time interactions (P ≥ 0.78) for cortisol following either exercise or bone insult. In conclusion, submaximal exercise did not result in re-release of clodronate; however, direct bone insult disrupted clodronate concentrations in horses receiving 4 administrations of bisphosphonate despite no treatment impact on stress or pain indicators.

Pharmacokinetics of nano- and microcrystal formulations of low solubility compounds after intramuscular injection to mice.

The aim of this study was to investigate the pharmacokinetics (PK) of poorly soluble compounds when administered intramuscularly (i.m.) as crystalline particles of different sizes. Three uncharged compounds (griseofulvin, AZ'72, and AZ'07) with varying aqueous solubility were dosed to mice at 10 and 50mg/kg as nano- and microparticle formulations. The PK of the compounds was evaluated. The smaller particles of the drugs resulted in higher maximum plasma concentration (Cmax) and area under the plasma concentration-time profile (AUC) at 50mg/kg. There was a dose-proportional increase in AUC but less than dose dose-proportional increase in Cmax. The evaluation at 10mg/kg was more complex as increased exposure for nanoparticles was only observed for griseofulvin which has the highest solubility. In addition, there was an increase in half-life with an increase in dose. This study highlights that general expectations based on in vitro dissolution (i.e. that smaller particles dissolve faster than larger particles when surrounded by liquid) do not always translate to in vivo and demonstrates the importance of understanding the physicochemical properties of the drug, the characteristics of the formulations and the microphysiology at the delivery site.

PSXII-11 Impact of pre-breeding and breeding supplementation in May-born range heifers on growth rates and reproductive performance

Abstract Our objectives were to determine the impact rumen undegradable protein (RUP) supplementation prior to and during the breeding season had on growth rates and reproductive performance in May-born yearling range heifers. This study was conducted over a 3-yr period at the University of Nebraska, Gudmundsen Sandhills Laboratory (GSL) near Whitman, NE and utilized May-born Red Angus x Simmental crossbred heifers [n = 192; weaning body weight (BW) = 200 kg ± 28 kg]. Heifers were randomly assigned by pre-breeding BW to one of two treatments: 1) received 0.908 kg of a dried distillers grain supplement (DDGS; Supp, n = 66) pre-breeding through the breeding season or 2) received no supplement (NoSupp, n = 138). Each year, treatments were initiated in July and ended in August (55 ± 3 d). Using a C-Lock Smart Feeder (Rapid City, SD) heifers had individual access to their allotted DDGS supplementation. On average, NoSupp heifers consumed 0.09 kg/d (yr 1) and 0.02 kg/d (yr 2 and 3); whereas, Supp heifers averaged 0.59, 0.74, and 0.76 kg/d in yr 1, 2, and 3, respectively. Heifer BW was collected pre-trial (May), pre-breeding (July), breeding (August), pregnancy diagnosis (October), and pre-calving (April). Body condition score (BCS) was collected at pregnancy diagnosis (October) and pre-calving (April; Yr 1 and 2). Before each breeding season, two blood samples were collected 10 d apart to determine pubertal status. Heifers were synchronized with a single 5 mL intramuscular injection of prostaglandin F2 alpha (Lutalyse, Zoetis, Parsippany, NJ) 5 d after bull turnout during a 30 d natural service breeding season. Pregnancy diagnosis was determined via rectal ultrasound in October. No differences (P &amp;gt; 0.12) in BW were noted among treatments for all measurement timepoints. Moreover, SUPP heifers had greater (P &amp;lt; 0.02) average daily gain (ADG) from pre- trial to pregnancy diagnosis compared with NoSUPP heifers. However, there was no differences (P = 0.11) in ADG from pregnancy diagnosis to pre- calving. At pregnancy diagnosis (October), a treatment x year interaction (P = 0.02) for BCS was present where Supp heifers had a greater BCS than NoSupp heifers in yr 3. Heifer BCS pre-calving was not affected (P = 0.12) by treatment. There was a greater percentage (P &amp;lt; 0.01) of SUPP heifers cycling compared with NoSUPP heifers. However, there were no differences (P &amp;gt; 0.24) in pregnancy rates, the percentage that calved in the first 21 d, calf birth BW, or subsequent calving date. Ultimately, this study implies that providing a RUP supplement prior to and during the breeding season will increase the percentage of heifers that are cycling before breeding and have a greater ADG through pregnancy diagnosis; however, supplementation will not impact other reproductive parameters or BW gains.