Last data update: Sep 23, 2024. (Total: 47723 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Nascimento Seixas J [original query] |
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Pharmacokinetic study of islatravir and etonogestrel implants in macaques
Daly MB , Wong-Sam A , Li L , Krovi A , Gatto GJ , Norton C , Luecke EH , Mrotz V , Forero C , Cottrell ML , Schauer AP , Gary J , Nascimento-Seixas J , Mitchell J , van der Straten A , Heneine W , Garcίa-Lerma JG , Dobard CW , Johnson LM . Pharmaceutics 2023 15 (12) The prevention of HIV and unintended pregnancies is a public health priority. Multi-purpose prevention technologies capable of long-acting HIV and pregnancy prevention are desirable for women. Here, we utilized a preclinical macaque model to evaluate the pharmacokinetics of biodegradable ε-polycaprolactone implants delivering the antiretroviral islatravir (ISL) and the contraceptive etonogestrel (ENG). Three implants were tested: ISL-62 mg, ISL-98 mg, and ENG-33 mg. Animals received one or two ISL-eluting implants, with doses of 42, 66, or 108 µg of ISL/day with or without an additional ENG-33 mg implant (31 µg/day). Drug release increased linearly with dose with median [range] plasma ISL levels of 1.3 [1.0-2.5], 1.9 [1.2-6.3] and 2.8 [2.3-11.6], respectively. The ISL-62 and 98 mg implants demonstrated stable drug release over three months with ISL-triphosphate (ISL-TP) concentr54ations in PBMCs above levels predicted to be efficacious for PrEP. Similarly, ENG implants demonstrated sustained drug release with median [range] plasma ENG levels of 495 [229-1110] pg/mL, which suppressed progesterone within two weeks and showed no evidence of altering ISL pharmacokinetics. Two of the six ISL-98 mg implants broke during the study and induced implant-site reactions, whereas no reactions were observed with intact implants. We show that ISL and ENG biodegradable implants are safe and yield sufficient drug levels to achieve prevention targets. The evaluation of optimized implants with increased mechanical robustness is underway for improved durability and vaginal efficacy in a SHIV challenge model. |
Effects of exogenous erythropoietin on rabbit (Oryctolagus cuniculus) hematological and biochemical parameters
Levine JK , Nascimento Seixas J , Ritter JM , Liew AY , Tansey CM . Comp Med 2023 73 (6) 439-45 Rabbits can develop anemia due to serial phlebotomy or secondary to induced disease states. This study evaluated theeffects of a single injection and three consecutive injections of erythropoietin in rabbits at 150 IU/kg and 1,000 IU/kg in orderto determine whether these dosages produce a sustained increase in hematocrit. Analysis of CBC and chemistry parametersshowed significant elevation in hematocrit one week after administration of 1,000 IU/kg erythropoietin for three consecutivedays. These results indicate that this dosage regimen can increase hematocrit in apparently healthy, nonanemic rabbits forone week. |
Mouse models of Ebola virus tolerance and lethality: Characterization of CD-1 mice infected with wild-type, guinea pig-adapted, or mouse-adapted variants
Spengler JR , Welch SR , Ritter JM , Harmon JR , Coleman-McCray JD , Genzer SC , Nascimento Seixas J , Scholte FEM , Davies KA , Bradfute SB , Montgomery JM , Spiropoulou CF . Antiviral Res 2022 210 105496 Development of lethal models of Ebola virus disease has been achieved by the serial passage of virus isolates from human cases in mice and guinea pigs. Use of mice infected with non-adapted virus has been limited due to the absence of overt clinical disease. In recent years, newly recognized sequelae identified in human cases has highlighted the importance of continued investigations of non-lethal infection both in humans and animal models. Here, we revisit the use of rodent-adapted and non-adapted Ebola virus (EBOV) variants in mice to investigate infection tolerance and future utility of these models in pathogenesis and therapeutic intervention studies. We found that like non-adapted wild-type EBOV, guinea pig-adapted EBOV results in widespread tissue infection, variably associated with tissue pathology, and alterations in clinical and immunological analytes in the absence of overt disease. Notably, infection with either non-lethal variant does not greatly differ from lethal mouse-adapted EBOV until near the time end-point criteria are reached in these mice, supporting use of these models of virus tolerance for continued investigations of non-lethal infection and sequelae. |
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