Publications by authors named "Douglas Thamm"

Article Synopsis
  • - The study aimed to discover how common undiagnosed malignant tumors are in healthy middle-aged to older dogs, specifically those aged 5.5 to 11.5 years.
  • - Out of 902 screened dogs, 2.7% were diagnosed with cancer, while an additional 3.3% had abnormalities that could indicate malignancy, raising the total to 6.0% when including suspected cases.
  • - The findings highlight that thorough physical exams, especially with aspiration cytology, are essential for effectively screening for cancer in older dogs.
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Article Synopsis
  • * Results showed that urine normetanephrine levels were significantly higher in dogs with pheochromocytomas, with a sensitivity of 78.9% and specificity of 76.9%, but many cases had low levels despite having tumors.
  • * The findings suggest that relying solely on urine metanephrine testing could miss many pheochromocytoma diagnoses, indicating the need for updated diagnostic guidelines.
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Acute myeloid leukemia (AML) poses significant challenges in veterinary medicine, with limited treatment options and poor survival rates. While substantial progress has been made in characterizing human AML, translating these advancements to veterinary practice has been hindered by limited molecular understanding and diagnostic tools. The case study presented illustrates the application of whole genome sequencing in diagnosing AML in a dog, showcasing its potential in veterinary oncology.

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Background: Dogs with lymphoma that fail cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy (CHOP) before completion of their protocol are commonly thought to have poor long-term outcome, but no previous studies have evaluated the effect of early relapse on progression-free interval (PFI) or overall survival time (OST) for patients undergoing rescue chemotherapy.

Objective: Correlate rescue treatment outcomes in dogs with multicentric lymphoma with outcomes after 1st-line CHOP chemotherapy.

Methods: Data were collected from 6 previous retrospective or prospective studies in 187 dogs with multicentric lymphoma that received 1st-line CHOP chemotherapy and then received either lomustine (CCNU), L-asparaginase and prednisone (LAP), or rabacfosadine (RAB, Tanovea), with or without prednisone or L-asparaginase.

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VDX-111 (also identified as AMPI-109) is a vitamin D derivative which has shown anticancer activity. To further assess the function of this compound against multiple cancer types, we examined the efficacy of VDX-111 against a panel of 30 well characterized canine cancer cell lines. Across a variety of cancer types, VDX-111 induced widely variable growth inhibition, cell death, and migration inhibition, at concentrations ranging from 10 nM to 1 μM.

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Ferroptosis is a cell death mechanism that has attracted significant attention as a potential basis for the development of new cancer therapies. Validation of ferroptosis biology in species commonly used in translation and pre-clinical development is a necessary foundation for enabling the advancement of such ferroptosis modulating drugs. Here, we demonstrate that canine cancer cells exhibit sensitivity to a wide range of ferroptosis-inducing perturbations in a manner indistinguishable from human cancer cells, and recapitulate characteristic patterns of ferroptotic response across tumor types seen in the human setting.

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The current standard of care treatment for canine lymphoma is a multi-agent, CHOP-based chemotherapy protocol. Single agent doxorubicin (DOX) is less burdensome; however, multi-agent chemotherapy protocols are often superior. The recently approved drug rabacfosadine (RAB, Tanovea) provides an attractive option for combination therapy with DOX, as both drugs demonstrate efficacy against lymphoma and possess different mechanisms of action.

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Novel Treatments for Lymphoma.

Vet Clin North Am Small Anim Pract

May 2024

Lymphoma is a common disease in companion animals. While conventional chemotherapy has the potential to induce remission and prolong life, relapse is common and novel treatments are needed to improve outcome. This review discusses recent modifications/adjustments to conventional standard of care therapy for canine and feline lymphoma, options for treatment or relapsed/refractory disease, and cutting-edge immunotherapy and small molecule-based approaches that are in varying stages of regulatory approval.

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This study provides a unique translational research opportunity to help both humans and dogs diagnosed with diseases that carry dismal prognoses in both species: histiocytic sarcoma (HS), hemangiosarcoma (HSA), and disseminated mastocytosis/mast cell tumor (MCT). Although exceedingly rare in humans, these so called "orphan diseases" are relatively more common in dogs. For these and other more commonplace cancers like lymphoma (Lym), dogs are an excellent translational model for human disease due to remarkably similar disease biology.

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Preventative anti-cancer vaccination strategies have long been hampered by the challenge of targeting the diverse array of potential tumor antigens, with successes to date limited to cancers with viral etiologies. Identification and vaccination against frameshift neoantigens conserved across multiple species and tumor histologies is a potential cancer preventative strategy currently being investigated. Companion dogs spontaneously develop cancers at a similar incidence to those in people and are a complementary comparative patient population for the development of novel anti-cancer therapeutics.

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Tumors in dogs and humans share many similar molecular and genetic features, incentivizing a better understanding of canine neoplasms not only for the purpose of treating companion animals, but also to facilitate research of spontaneously developing tumors with similar biologic behavior and treatment approaches in an immunologically competent animal model. Multiple tumor types of both species have similar dysregulation of signal transduction through phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB; AKT), and mechanistic target of rapamycin (mTOR), collectively known as the PI3K-AKT-mTOR pathway. This review aims to delineate the pertinent aspects of the PI3K-AKT-mTOR signaling pathway in health and in tumor development.

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Background: This study was performed to determine the ability to escalate drug doses in a 15-week CHOP protocol in dogs with multicentric lymphoma.

Hypothesis: We hypothesized that at least 50% of dogs could successfully be escalated in at least 1 drug. Secondary aims were to establish objective response rate (ORR), progression-free interval (PFI), and overall survival time (OST).

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Canine histiocytic sarcoma is an aggressive cancer, with a high rate of metastasis. Thus, novel therapeutic approaches are needed. Synthetic analogues of curcumin have elicited potent anti-cancer activity in multiple in vitro and in vivo models of human cancer.

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Background: Information on dogs that undergo limb preserving local treatment for ulnar tumors is currently limited.

Objective: To describe the clinical characteristics and outcomes in dogs that underwent partial ulnectomy or radiation therapy (RT) for ulnar bone tumors, and to evaluate potential risk factors for outcomes as well as pre-treatment factors for association with treatment modality selected.

Animals: Forty client-owned dogs that underwent partial ulnectomy or RT for an ulnar tumor from July 2006 to July 2021.

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Canine osteosarcoma is an aggressive cancer, comprising 85% of canine bone neoplasms. Current treatment practices of surgery and chemotherapy increase 1-year survival by only 45%. The curcumin analogue RL71, has demonstrated potent in vitro and in vivo efficacy in several models of human breast cancer through increased apoptosis and cell cycle arrest.

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Increased or constitutive activation of nuclear factor kappa B (NF-kB) is a feature of many chronic disease processes, including cancer. While NF-kB overactivation has been documented extensively in human oncology, there is a relative paucity of data documenting the same phenomenon in veterinary medicine. To assess NF-kB activity, antibodies to p65 and p100/p52, which are components of NF-kB heterodimers, were first validated for specificity and canine cross-reactivity via Western blot and labeling of immortalized cell pellets.

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Macrophages are ancient, phagocytic immune cells thought to have their origins 500 million years ago in metazoan phylogeny. The understanding of macrophages has evolved to encompass their foundational roles in development, homeostasis, tissue repair, inflammation, and immunity. Notably, macrophages display high plasticity in response to environmental cues, capable of a strikingly wide variety of dynamic gene signatures and phenotypes.

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For some cases of canine appendicular osteosarcoma (OSA), limb-sparing treatment options are often desired, one of which is stereotactic body radiation therapy (SBRT). A major complication of SBRT is fracture of the irradiated bone at the site of treatment. The present study evaluated 127 appendicular OSA sites in 122 dogs treated with SBRT to identify the most common pathologic fracture locations and configurations.

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Objective: To report the survival times in dogs that received a standardized palliative-intent radiation therapy (RT) protocol for the treatment of canine appendicular osteosarcoma (OSA), alone or in combination with bisphosphonates (BPs), and to determine whether the addition of BPs affects survival. A secondary objective was to identify prognostic features that may influence outcome in dogs undergoing treatment.

Design: Retrospective case series.

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Spontaneous tumors in dogs share several environmental, epidemiologic, biologic, clinical and molecular features with a wide variety of human cancers, making this companion animal an attractive model. Nuclear factor kappa B (NF-kB) transcription factor overactivation is common in several human cancers, and there is evidence that similar signaling aberrations also occur in canine cancers including lymphoma, leukemia, hemangiosarcoma, mammary cancer, melanoma, glioma, and prostate cancer. This review provides an overview of NF-kB signaling biology, both in health and in cancer development.

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Background: Rabacfosadine (RAB, Tanovea-CA1) is a novel chemotherapy agent conditionally approved for the treatment of lymphoma in dogs.

Hypothesis/objectives: To determine the efficacy and safety of RAB in dogs with lymphoma.

Animals: One hundred and fifty-eight client-owned dogs with naïve or relapsed multicentric lymphoma were prospectively enrolled from January to October 2019.

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Patients with cancer-induced bone disease, including primary bone cancers such as osteosarcoma (OS) and metastases from other tissues of origin, present a high unmet medical need. We present a potential therapeutic approach built upon a proven bone-targeting bisphosphonate conjugate platform with the known synergies of gemcitabine (GEM) and docetaxel (DTX). The synthesis of rationally designed GEM-IB, the conjugate of GEM-5'-phosphate with ibandronate (IB), is presented.

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Objective: To determine the effects of morphine on histamine release from 2 canine mast cell tumor (MCT) cell lines and on plasma histamine concentrations in dogs with cutaneous MCTs.

Animals: 10 dogs with cutaneous MCT and 10 dogs with soft tissue sarcoma (STS).

Procedures: The study consisted of 2 phases.

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Splenic stromal sarcomas are rarely reported tumours that were previously grouped as non-angiomatous, non-lymphomatous mesenchymal neoplasms of the canine spleen. Highly variable survival times have been reported probably due to their heterogeneous nature. The purpose of this study was to assess the outcome and prognostic factors in dogs with splenic stromal sarcoma after treatment by splenectomy.

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