Mechanisms of Herb-Drug Interactions Involving Cinnamon and CYP2A6: Focus on Time-Dependent Inhibition by Cinnamaldehyde and 2-Methoxycinnamaldehyde.

Information is scarce regarding pharmacokinetic-based herb-drug interactions (HDI) with -cinnamaldehyde (CA) and 2-methoxycinnamaldehyde (MCA), components of cinnamon. Given the presence of cinnamon in food and herbal treatments for various diseases, HDIs involving the CYP2A6 substrates nicotine and letrozole with MCA (K = 1.58 µM; Hill slope = 1.

Critical functions of the polyamine putrescine for proliferation and viability of Leishmania donovani parasites.

Polyamines are metabolites that play important roles in rapidly proliferating cells, and recent studies have highlighted their critical nature in Leishmania parasites. However, little is known about the function of polyamines in parasites. To address this question, we assessed the effect of polyamine depletion in Leishmania donovani mutants lacking ornithine decarboxylase (Δodc) or spermidine synthase (Δspdsyn).

Valproic acid as an adjunctive therapeutic agent for the treatment of breast cancer.

Breast cancer is one of the leading causes of cancer-related death among women. A significant challenge in treating breast cancer is the limited array of therapeutic options and the rapid development of resistance to existing agents. Indeed, breast cancer patients, particularly those with hormone-receptor (HR)-positive breast cancer, initially respond to systemic treatment with cytotoxic, hormonal, and immunotherapeutic agents but frequently progress to a more advanced disease that is refractory to therapy.

Forecasting academic success through implementation of an online prerequisite review tutorials program for first year pharmacy students.

Objective: Online prerequisite review (OPR) tutorials were designed and implemented to reinforce foundational scientific material in order to protect in-class time, foster self-directed learning, and ensure all students have similar baseline knowledge.

Methods: Twenty-one tutorials covering undergraduate prerequisite material were developed by faculty and organized into six core modules, comprising basic biology, chemistry, and physiology topics. A quiz on this material was given on the first day of each course.

Expanding the view of breast cancer metabolism: Promising molecular targets and therapeutic opportunities.

The changes in breast cancer cells that contribute to tumor evolution, heterogeneity, metastasis and ultimately drug resistance are shaped by numerous genetic changes including alterations in cellular metabolism. These include intermediary metabolic pathways such as glycolysis, the citric acid cycle oxidative phosphorylation, amino acid synthesis and lipid metabolism. However, cancer cells also exhibit key alterations in other metabolic pathways involved in drug metabolism such as cytochrome P450 enzymes, sulfotransferase and steroid sulfatases that are involved in the synthesis of estrogens and themselves serve as drug targets.

Inactivation of CYP2A6 by the Dietary Phenylpropanoid trans-Cinnamic Aldehyde (Cinnamaldehyde) and Estimation of Interactions with Nicotine and Letrozole.

Human exposure to trans-cinnamic aldehyde [t-CA; cinnamaldehyde; cinnamal; (E)-3-phenylprop-2-enal] is common through diet and through the use of cinnamon powder for diabetes and to provide flavor and scent in commercial products. We evaluated the likelihood of t-CA to influence metabolism by inhibition of P450 enzymes. IC50 values from recombinant enzymes indicated that an interaction is most probable for CYP2A6 (IC50 = 6.

Allosteric modulation of substrate motion in cytochrome P450 3A4-mediated xylene oxidation.

Many cytochrome P450 enzymes (CYPs) exhibit allosteric behavior reflecting a complex ligand-binding process involving numerous factors: conformational selection, protein-protein interactions, substrate/effector/protein structure, and multiple-ligand binding. The interplay of CYP plasticity and rigidity contributes to substrate/product selectivity and to allosterism. Detailed evidence describing how protein motion modulates product selectivity is incomplete as are descriptions of effector-induced modulation of substrate dynamics.

Leiomyosarcoma of the somatic soft tissues.

Leiomyosarcomas of the somatic soft tissues are tumors of smooth muscle origin that occur in the extremities. These lesions are commonly high-grade tumors that carry a poor prognosis. Recommended treatment often includes wide excision and chemotherapy or radiation therapy.

Covalent modification and time-dependent inhibition of human CYP2E1 by the meta-isomer of acetaminophen.

The hypothesis that N-acetyl-m-aminophenol (AMAP), the meta isomer of acetaminophen, will covalently bind to and inhibit human CYP2E1 in a time- and NADPH-dependent manner was investigated. Liquid chromatography/electrospray ionization-mass spectrometry analysis indicated that AMAP metabolites (i.e.

Predictions of cytochrome P450-mediated drug-drug interactions using cryopreserved human hepatocytes: comparison of plasma and protein-free media incubation conditions.

Cryopreserved human hepatocytes suspended in human plasma (HHSHP) have previously provided accurate CYP3A drug-drug interaction (DDI) predictions from a single IC(50) that captures both reversible and time-dependent inhibition. The goal of this study was to compare the accuracy of DDI predictions by a protein-free human hepatocyte system combined with the fraction unbound in plasma for inhibitor(s) with those obtained with protein-containing incubations. Seventeen CYP3A, CYP2C9, or CYP2D6 inhibitors were incubated with hepatocytes in human plasma or hepatocyte maintenance medium (HMM) for 20 min over a range of concentrations after which midazolam 1'-hydroxylation, diclofenac 4'-hydroxylation or (R)-bufuralol 1'-hydroxylation were used to quantify the corresponding cytochrome P450 (P450) catalytic activities.

Prediction of CYP3A-mediated drug-drug interactions using human hepatocytes suspended in human plasma.

Cryopreserved human hepatocytes suspended in human plasma (HHSHP) represent an integrated metabolic environment for predicting drug-drug interactions (DDIs). In this study, 13 CYP3A reversible and/or time-dependent inhibitors (TDIs) were incubated with HHSHP for 20 min over a range of concentrations after which midazolam 1'-hydroxylation was used to measure CYP3A activity. This single incubation time method yielded IC(50) values for the 13 inhibitors.

Multiple-ligand binding in CYP2A6: probing mechanisms of cytochrome P450 cooperativity by assessing substrate dynamics.

The contribution of ligand dynamics to CYP allosterism has not been considered in detail. On the basis of a previous study, we hypothesized that CYP2A6 and CYP2E1 accommodate multiple xylene ligands. As a result, the intramolecular ( k H/ k D) obs values observed for some xylene isomers are expected to be dependent on ligand concentration with contributions from [CYP.

A comparison of substrate dynamics in human CYP2E1 and CYP2A6.

Considering the dynamic nature of CYPs, methods that reveal information about substrate and enzyme dynamics are necessary to generate predictive models. To compare substrate dynamics in CYP2E1 and CYP2A6, intramolecular isotope effect experiments were conducted, using deuterium labeled substrates: o-xylene, m-xylene, p-xylene, 2,6-dimethylnaphthalene, and 4,4'-dimethylbiphenyl. Competitive intermolecular experiments were also conducted using d(0)- and d(6)-labeled p-xylene.

The effect of intermittent pneumatic compression on fracture healing.

Objectives: Continuously increased venous pressure has been shown to enhance bone growth, stimulate fracture healing, and prevent bone loss, but also causes soft-tissue breakdown as a result of chronic edema. This study was designed to test the hypothesis that intermittently increased venous pressure improves fracture healing without injuring soft tissue.

Design: An ostectomy was created in the right radius of 30 skeletally mature male beagles.

Treatment of osseous metastases in patients with renal cell carcinoma.

The records of 99 patients treated at one institution for osseous metastases secondary to renal cell carcinoma were reviewed. Patients were followed up for at least 24 months or until death. Survival was analyzed with respect to age, gender, disease-free interval, location of osseous metastases, number of osseous metastatic sites, resection of osseous metastases, and primary tumor resection.

Utility of fine-needle aspiration in the diagnosis of primary osteosarcoma.

Fine-needle aspiration (FNA) is a reliable, safe, and cost-effective procedure with a well-established role in the diagnosis of various solid tissue neoplasms. The role of FNA in the diagnosis of primary bone tumors, including osteosarcoma (OGS), is controversial and has yet to be established. We reviewed our experience with the use of FNA as a diagnostic technique over the past 8 yr at our institution.

Intramuscular myxoma: a clinicopathologic study of 17 patients.

The office and hospital records of 17 patients treated for intramuscular myxomas between 1979 and the present were reviewed. Thirteen women and four men were diagnosed with an intramuscular myxoma at an average age of 55 years (range, 31-76 years). Each patient presented with a noticeable mass, and six patients had symptoms of pain or aching related to the mass.

Giant-cell tumor of the appendicular skeleton.

The common objective of all surgical procedures in the treatment of giant-cell tumor of bone is to minimize the incidence of local recurrence. The purpose of this study was to determine what, if any, patient factors, tumor characteristics, or surgical practices correlate with local recurrence. Seventy-five patients treated for a giant-cell tumor of the appendicular skeleton were followed up for at least 2 years.