The impact of vector control on the prevalence of Theileria cervi in farmed Florida white-tailed deer, Odocoileus virginianus.

BACKGROUND: Vector-borne diseases exert a global economic impact to the livestock industry. Understanding how agriculture practices and acaricide usage affect the ecology of these diseases is important for making informed management decisions. Theileria cervi is a hemoprotozoan parasite infecting white-tailed deer (Odocoileus virginianus) and is transmitted by the lone star tick, Amblyomma americanum. The purpose of this study was to determine if acaricide treatment decreased hematozoan prevalence in farmed white-tailed deer when compared to geographically-close wild deer or altered the genotypes of T. cervi present. RESULTS: We compared prevalence of T. cervi in 52 farmed adult white-tailed deer which were regularly treated with permethrin and ivermectin, 53 farmed neonates that did not receive treatment for vector control, and 42 wild deer that received no form of chemical vector control. Wild deer had significantly higher prevalence of T. cervi than farmed deer. Additionally, no neonate fawns tested positive for T. cervi, and we found that age was a significant predictor of infection status. We found no difference in genotypic variation in T. cervi isolates between adjacent herds of farmed and wild white-tailed deer, although a divergent genotype X was identified. Chronic infection with T. cervi had no significant effects on mortality in the white-tailed deer. CONCLUSIONS: We found significantly lower prevalence of T. cervi infection in farmed (40%) compared to wild white-tailed deer (98%), which may be due to the inclusion of chemical vector control strategies. More work is needed to determine the implications, if any, of mixed genotypic infections of T. cervi, although we found no significant effect of infection with Theileria on mortality in farmed deer. Theileria infection does sometimes cause disease when an animal is stressed, immunosuppressed, or translocated from non-endemic to endemic regions.

Discovery of a novel, orally active, small molecule gonadotropin-releasing hormone (GnRH) receptor antagonist.

Gonadotropin releasing hormone (GnRH) plays an important role in the biology of reproduction. The use of GnRH receptor antagonists has been reported in the literature for the treatment of breast, ovarian, and prostate cancers. In this article, we report the synthesis, in vitro characterization, pharmacokinetics, and pharmacodynamics of an orally bioavailable, potent, small molecule GnRH receptor antagonist N-{4,6-dimethoxy-2-[(3-morpholin-4-ylpropyl)amino]pyrimidin-5-yl}-5-[3,3,6-trimthyl-2,3-dihydro-1H-inden-5-yl)oxy]-2-furamide (compound 1).

A phase II study of pemetrexed in patients with advanced hepatocellular carcinoma.

Pemetrexed has demonstrated activity in hepatocellular carcinoma (HCC) cell lines, and has a manageable toxicity profile in clinical trials, suggesting its potential as a treatment for HCC patients. A multicenter, Phase II community-based study was conducted to assess the response rate and toxicity profile of single-agent pemetrexed in first-line patients with advanced or metastatic HCC. Patients premedicated with folic acid, vitamin B(12), and dexamethasone were administered pemetrexed 600 mg/m(2) IV on day 1 of each 21-day cycle until disease progression. This nonrandomized study employed Simon's 2-stage design, enrolling 21 eligible patients in the first stage, stopping accrual if < or =2 responders were observed. Responses were four stable disease, 14 progressive disease, and three not evaluable: two had early toxicities (renal/liver failure, sepsis) and one was noncompliant. The most common grade 3 hematological toxicities were neutropenia 6 of 21 (29%) and thrombocytopenia 3 of 21 (14%); with no grade 4 toxicities. Thirteen patients died on-study: 12 PD and one liver failure; none were drug-related. The median survival was 5.2 months (range, <1-12.2). The planned second stage was cancelled, and the trial was closed owing to lack of response. While pemetrexed was tolerated in this patient population, it was not active.

Phase I study of a 3-drug regimen of gemcitabine/cisplatin/pemetrexed in patients with metastatic transitional cell carcinoma of the urothelium.

OBJECTIVES: Gemcitabine (G) plus cisplatin (C) is standard care for metastatic transitional cell carcinoma (TCC) of the urothelium. Pemetrexed (P), alone or in combination with G, is active in metastatic TCC. However, the safety and efficacy of P combined with GC therapy is unknown. This phase I trial was designed to determine the maximum tolerated dose (MTD) of GC followed by P+G in patients with metastatic TCC. METHODS: Cohorts of 3 to 6 patients received escalating doses 28-day cycles (maximum 6 cycles): G 800-1,000 mg/m2 on days 1 and 15; P 400-500 mg/m2 on day 15; and C 50-70 mg/m2 on day 1. All patients received folic acid, vitamin B12, and full supportive care. The 3+3 standard phase I escalation rule was used to determine MTD. RESULTS: Fifteen patients registered: 13/15 white males; median age 70 years (range, 53-82); 11/15 had KPS>or=90. At dose level 0, 2/4 patients experienced unrelated DLTs, and 1 patient was replaced (completed<1 cycle). Dose escalation proceeded to dose level 1. At level 1, 4/6 patients experienced DLTs; dosing decreased to level 0 and 4/5 patients experienced DLTs. The MTD was not determined. The 2 patients that completed 6 cycles both had partial responses. Grades 3-4 hematologic toxicities included neutropenia (60%), leukopenia (20%), and febrile neutropenia (13%). CONCLUSION: Adding P to the standard GC regimen as first-line therapy for metastatic TCC produced no benefit. The MTD exceeded therapeutic gemcitabine and cisplatin doses for urothelial cancer and thus the study was aborted.

Characterization of mono- and diaminopyrimidine derivatives as novel, nonpeptide gonadotropin releasing hormone (GnRH) receptor antagonists.

A novel series of derivatives of mono- and diaminopyrimidines 1 potently displaced binding of a radiolabeled GnRH analogue to human and rat GnRH receptors. Analogues from these series competitively antagonized GnRH-stimulated increases in extracellular acidification in vitro and suppressed GnRH-mediated increases in circulating luteinizing hormone (LH) in castrated rats and testosterone in intact rats. These compounds or their analogues may be useful in treating sex hormone-dependent disease.

The discovery of novel small molecule non-peptide gonadotropin releasing hormone (GnRH) receptor antagonists.

A novel series of non-peptide derivatives 1, 14, and 15 that bind with high affinity to the human GnRH receptors is discussed. The discovery was made from screening our in-house libraries that contained the active structure 2 along with a trace amount of a second active structure 1 that was derived from an acid-induced rearrangement. From this structure type 1, a series of guanidine and non-guanidine containing analogues were prepared and tested as GnRH receptor antagonists. Compounds derived from this series bind to both human and rat GnRH receptors and antagonize GnRH-mediated increases in inositol phosphate production in cells containing recombinant human receptors. These compounds or their analogues may be useful as therapeutic agents for the treatment of hormone-dependent pathologies including prostate, breast and ovarian cancers.

Biological characterization of a novel, orally active small molecule gonadotropin-releasing hormone (GnRH) antagonist using castrated and intact rats.

Gonadotropin-releasing hormone (GnRH) receptor antagonists have potential in treating numerous hormone-dependent pathologies including cancers of the prostate, breast, and ovary, endometriosis, and fertility disorders. An unmet clinical need exists for an orally available GnRH receptor antagonist. Guided by structure-activity relationships, ligand-based targeted library designs, and biomarker measurements, our discovery efforts have yielded a novel, small molecule GnRH receptor antagonist, 5-[(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthalenyl)methyl]-N-(2,4,6-trimethoxyphenyl)-2-furamide (CMPD1). CMPD1 bound with low nanomolar affinities to human, rat, and mouse GnRH receptors (6.0, 3.8, and 2.2 nM, respectively). CMPD1 was more than 100-fold selective for GnRH receptors versus various G-protein-coupled receptors and other enzymes and ion channels. In cells expressing recombinant rat GnRH receptors, CMPD1 was a competitive antagonist of GnRH-stimulated increases in extracellular acidification rates in Cytosensor microphysiometer assays. In cells expressing recombinant human GnRH receptors, CMPD1 was a potent inhibitor of GnRH-stimulated total inositol phosphate accumulation. The effects of CMPD1 on circulating levels of luteinizing hormone (LH) and testosterone were studied in castrated and intact male rats, respectively. Intravenous and oral administration of CMPD1 dose dependently suppressed GnRH-mediated elevations of LH in castrated male rats and testosterone in gonad-intact male rats. Moreover, CMPD1, when given at 20 mg/kg i.v. to intact male rats, inhibited the elevations of LH and testosterone stimulated by the superagonist of GnRH, [d-Ala(6), des-Gly(10)]GnRH (GnRH-A). These data suggest that CMPD1 is a potent, selective, orally active GnRH receptor antagonist that may have potential application as a therapeutic agent for treating hormone-dependent cancers and diseases.