Publications by authors named "Larry Handt"

Kidney biopsies are used sparingly to diagnose kidney injury in the clinic. Here we have conducted a small exploratory study to directly compare the low-grade kidney injury monitoring performance of serum safety biomarkers, novel urine safety biomarkers, microscopic histopathology and targeted gene expression alterations in kidney biopsy specimens in rhesus monkeys treated with tobramycin. Targeted gene expression increases were observed in the kidney biopsy samples and whole kidney sections for kidney injury molecule 1 (), clusterin (), osteopontin () messenger RNA transcripts.

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Until recently, preclinical and clinical work on diabetes has focused on the understanding of blood glucose elevation and its detrimental metabolic sequelae. The advent of continuous glucose monitoring (CGM) technology now allows real time monitoring of blood glucose levels as a time series, and thus the exploration of glucose dynamics at short time scales. Previous work has shown decreases in the complexity of glucose dynamics, as measured by multiscale entropy (MSE) analysis, in diabetes in humans, mice, and rats.

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Platelet activation plays a crucial role in hemostasis and thrombosis. Thrombin, the most potent stimulus of platelet activation, mediates platelet activation via the protease activated receptors (PARs). The platelet PAR repertoire in mediating thrombin's action differs across species.

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Vorapaxar is a novel protease-activated receptor-1 (PAR-1) antagonist recently approved for the reduction of thrombotic cardiovascular events in patients with a history of myocardial infarction or with peripheral arterial disease. Patients who received vorapaxar in addition to standard of care antiplatelet therapy had an increased incidence of major bleeding events compared with placebo. To assess whether platelet transfusion can restore hemostasis in primates on triple antiplatelet therapy, template bleeding times were assessed concurrently in the buccal mucosa, finger pad, and distolateral tail of anesthetized cynomolgus macaques to evaluate bleeding with vorapaxar as either monotherapy or in combination with aspirin or aspirin and clopidogrel.

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Efforts to develop novel, interferon-sparing therapies for treatment of chronic hepatitis C (HCV) infection are contingent on the ability of combination therapies consisting of direct antiviral inhibitors to achieve a sustained virologic response. This work demonstrates a proof of concept that coadministration of the nucleoside analogue MK-0608 with the protease inhibitor MK-7009, both of which produced robust viral load declines as monotherapy, to an HCV-infected chimpanzee can achieve a cure of infection.

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Hepatitis C virus (HCV) infects an estimated 170 million individuals worldwide and is associated with an increased incidence of liver fibrosis, cirrhosis, and hepatocellular carcinoma. Currently approved therapies to treat HCV infection consist of combinations of pegylated alpha interferon and ribavirin which result in a sustained viral response in 40 to 60% of patients. Efforts to develop improved therapies include the development of direct inhibitors of virally encoded enzymes such as the viral RNA-dependent RNA polymerase.

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Enrofloxacin is used for treating Shigellosis in non-human primates; however, there are no reports describing its pharmacokinetics in rhesus monkeys. Pharmacokinetic data in intended target species (rhesus) help to determine the proper dose regimen. Blood levels of enrofloxacin and ciprofloxacin (enrofloxacin's active metabolite), were determined after either intramuscular or oral dosing of enrofloxacin for 7 days in a cross-over study.

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Tuberculosis (TB) is the most important zoonotic bacterial disease in nonhuman primates (NHP). The current diagnostic method, the intradermal palpebral tuberculin test, has serious shortcomings. We characterized antibody responses in NHP against Mycobacterium tuberculosis to identify immunodominant antigens and develop a rapid serodiagnostic test for TB.

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Lack of virus specific antibody response is commonly observed in both HIV-1-infected humans and SIV-infected monkeys with rapid disease progression. However, the mechanisms underlying this important observation still remain unclear. In a titration study of a SIVmac239 viral stock, three out of six animals with viral inoculation rapidly progressed to AIDS within 5 months.

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Simian-human immunodeficiency virus (SHIV) challenge studies in rhesus macaques were conducted to evaluate the efficacy of adenovirus-based vaccines in the context of different major histocompatibility complex class I genetic backgrounds and different vaccine compositions. Mamu-A*01 allele-negative rhesus monkeys were immunized with one of the following vaccine constructs: (i) replication-defective recombinant adenovirus type 5 (Ad5) expressing human immunodeficiency virus type 1 (HIV-1) Tat (Ad5/HIVTat); (ii) Ad5 vector expressing simian immunodeficiency virus (SIV) Gag (Ad5/SIVGag); (iii) Ad5 vector expressing the truncated HIV-1(jrfl) Env, gp140 (Ad5/gp140_jrfl); (iv) Ad5 vector expressing the SHIV-89.6P gp140 (Ad5/gp140_89.

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We describe the efficacy of L-870812, an inhibitor of HIV-1 and SIV integrase, in rhesus macaques infected with the simian-human immunodeficiency virus (SHIV) 89.6P. When initiated before CD4 cell depletion, L-870812 therapy mediated a sustained suppression of viremia, preserving CD4 levels and permitting the induction of virus-specific cellular immunity.

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Set-point viral load is positively correlated with the extent of initial viral replication in pathogenic simian-human immunodeficiency virus (SHIV) infection. To elucidate the mechanisms underlying the correlation, we conducted a systematic investigation in rhesus monkeys infected with the highly pathogenic SHIV 89.6P.

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Over a 21-month period, three Beagle dogs and one mixed-breed dog at our facility developed fatal pneumonia. The four dogs, all purpose bred, came from three vendors and had received the standard canine vaccines prior to shipment. In each instance, the affected dog had been shipped to our facility within the past 10 days.

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Expression of several major histocompatibility complex (MHC) class I alleles is associated with a protective effect against disease progression in both human immunodeficiency virus type 1 and simian immunodeficiency virus infection. To understand the mechanism underlying this effect, we investigated the expression of the MHC class I allele Mamu-A*01 in simian-human immunodeficiency virus (SHIV) infection, one of the major models for evaluation of AIDS vaccine candidates. We found that disease progression was significantly delayed in Mamu-A*01-positive rhesus monkeys infected with the highly pathogenic SHIV 89.

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Recent studies of human immunodeficiency virus type 1 (HIV-1) infection in humans and of simian immunodeficiency virus (SIV) in rhesus monkeys have shown that resolution of the acute viral infection and control of the subsequent persistent infection are mediated by the antiviral cellular immune response. We comparatively assessed several vaccine vector delivery systems-three formulations of a plasmid DNA vector, the modified vaccinia Ankara (MVA) virus, and a replication incompetent adenovirus type 5 (Ad5) vector-expressing the SIV gag protein for their ability to elicit such immune responses in monkeys. The vaccines were tested either as a single modality or in combined modality regimens.

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