Pharmacy and Pharmaceutical Sciences Commons^™

Engineered Nanomaterials: Exposures, Hazards, And Risk Prevention, Robert A. Yokel, Robert C. Macphail

Pharmaceutical Sciences Faculty Publications

Nanotechnology presents the possibility of revolutionizing many aspects of our lives. People in many settings (academic, small and large industrial, and the general public in industrialized nations) are either developing or using engineered nanomaterials (ENMs) or ENM-containing products. However, our understanding of the occupational, health and safety aspects of ENMs is still in its formative stage. A survey of the literature indicates the available information is incomplete, many of the early findings have not been independently verified, and some may have been over-interpreted. This review describes ENMs briefly, their application, the ENM workforce, the major routes of human exposure, some …

An Epichromatin Epitope: Persistence In The Cell Cycle And Conservation In Evolution, Ada L. Olins, Markus Langhans, Marc Monestier, Andreas Schlotterer, David G. Robinson, Corrado Viotti, Hanswalter Zentgraf, Monika Zwerger, Donald E. Olins

Pharmaceutical Sciences Faculty Publications

Interphase nuclear architecture is disrupted and rapidly reformed with each cell division cycle. Successive cell generations exhibit a “memory” of this nuclear architecture, as well as for gene expression. Furthermore, many features of nuclear and mitotic chromosome structure are recognizably species and tissue specific. We wish to know what properties of the underlying chromatin structure may determine these conserved features of nuclear architecture. Employing a particular mouse autoimmune anti-nucleosome monoclonal antibody (PL2-6), combined with deconvolution immunofluorescence microscopy, we present evidence for a unique epitope (involving a ternary complex of histones H2A and H2B and DNA) which is localized only at …

An In Vitro Model For Pelger-Huët Anomaly, Ada L. Olins, Aurélie Ernst, Monika Zwerger, Harald Hermann, Donald E. Olins

Pharmaceutical Sciences Faculty Publications

The principal human blood granulocyte (neutrophil) possesses a lobulated and deformable nucleus, important to facilitate rapid egress from blood vessels as these cells migrate to sites of bacterial or fungal infection. This unusual nuclear shape is a product of elevated levels of an integral membrane protein of the nuclear envelope lamin B receptor (LBR) and of decreased amounts of lamin A/C. In humans, a genetic deficiency of LBR produces Pelger-Huët anomaly, resulting in blood neutrophils that exhibit hypolobulated nuclei with redistributed heterochromatin. Structural changes in nuclear architecture occur during granulopoiesis within bone marrow. The exact mechanisms of this nuclear shape …

Plant Phenolics: Extraction, Analysis And Their Antioxidant And Anticancer Properties, Jin Dai, Russell J. Mumper

Pharmaceutical Sciences Faculty Publications

Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. In the last few years, the identification and development of phenolic compounds or extracts from different plants has become a major area of health- and medical-related research. This review provides an updated and comprehensive overview on phenolic extraction, purification, analysis and quantification as well as their antioxidant properties. Furthermore, the anticancer effects of phenolics in-vitro …

Materials For Pharmaceutical Dosage Forms: Molecular Pharmaceutics And Controlled Release Drug Delivery Aspects, Heidi M. Mansour, Minji Sohn, Abeer Al-Ghananeem, Patrick P. Deluca

Pharmaceutical Sciences Faculty Publications

Controlled release delivery is available for many routes of administration and offers many advantages (as microparticles and nanoparticles) over immediate release delivery. These advantages include reduced dosing frequency, better therapeutic control, fewer side effects, and, consequently, these dosage forms are well accepted by patients. Advances in polymer material science, particle engineering design, manufacture, and nanotechnology have led the way to the introduction of several marketed controlled release products and several more are in pre-clinical and clinical development.

Inhibition Of Abcb1 (Mdr1) Expression By An Sirna Nanoparticulate Delivery System To Overcome Drug Resistance In Osteosarcoma, Michiro Susa, Arun K. Iyer, Keinosuke Ryu, Edwin Choy, Francis J. Hornicek, Henry Mankin, Lara Milane, Mansoor M. Amiji, Zhenfeng Duan

Pharmaceutical Sciences Faculty Publications

Background: The use of neo-adjuvant chemotherapy in treating osteosarcoma has improved patients’ average 5 year survival rate from 20% to 70% in the past 30 years. However, for patients who progress after chemotherapy, its effectiveness diminishes due to the emergence of multi-drug resistance (MDR) after prolonged therapy.

Methodology/Principal Findings: In order to overcome both the dose-limiting side effects of conventional chemotherapeutic agents and the therapeutic failure resulting from MDR, we designed and evaluated a novel drug delivery system for MDR1 siRNA delivery. Novel biocompatible, lipid-modified dextran-based polymeric nanoparticles were used as the platform for MDR1 siRNA delivery; and the efficacy …

Lamin B Receptor, Ada L. Olins, Gale Rhodes, David B. Mark Welch, Monika Zwerger, Donald E. Olins

Pharmaceutical Sciences Faculty Publications

Lamin B Receptor (LBR) is an integral membrane protein of the interphase nuclear envelope (NE). The N-terminal end resides in the nucleoplasm, binding to lamin B and heterochromatin, with the interactions disrupted during mitosis. The C-terminal end resides within the inner nuclear membrane, retreating with the ER away from condensing chromosomes during mitotic NE breakdown. Some of these properties are interpretable in terms of our current structural knowledge of LBR, but many of the structural features remain unknown. LBR apparently has an evolutionary history which brought together at least two ancient conserved structural domains (i.e. Tudor and sterol reductase). This …

Manganese Flux Across The Blood-Brain Barrier, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

Manganese (Mn) is essential for brain growth and metabolism, but in excess can be a neurotoxicant. The chemical form (species) of Mn influences its kinetics and toxicity. Significant Mn species entering the brain are the Mn²⁺ ion and Mn citrate which, along with Mn transferrin, enter the brain by carrier-mediated processes. Although the divalent metal transporter (DMT-1) was suggested to be a candidate for brain Mn uptake, brain Mn influx was not different in Belgrade rats, which do not express functional DMT-1, compared to controls. Brain Mn influx was not sodium dependent or dependent on ATP hydrolysis, but was …

Doxorubicin Loaded Polymeric Nanoparticulate Delivery System To Overcome Drug Resistance In Osteosarcoma, Michiro Susa, Arun K. Iyer, Keinosuke Ryu, Francis J. Hornicek, Henry Mankin, Mansoor M. Amiji, Zhenfeng Duan

Pharmaceutical Sciences Faculty Publications

Background: Drug resistance is a primary hindrance for the efficiency of chemotherapy against osteosarcoma. Although chemotherapy has improved the prognosis of osteosarcoma patients dramatically after introduction of neo-adjuvant therapy in the early 1980's, the outcome has since reached plateau at approximately 70% for 5 year survival. The remaining 30% of the patients eventually develop resistance to multiple types of chemotherapy. In order to overcome both the dose-limiting side effects of conventional chemotherapeutic agents and the therapeutic failure incurred from multidrug resistant (MDR) tumor cells, we explored the possibility of loading doxorubicin onto biocompatible, lipid-modified dextran-based polymeric nanoparticles and evaluated the …

Effects Of Genetic Deficiency Of Cyclooxygenase-1 Or Cyclooxygenase-2 On Functional And Histological Outcomes Following Traumatic Brain Injury In Mice, Matthew L. Kelso, Stephen W. Scheff, James R. Pauly, Charles D. Loftin

Pharmaceutical Sciences Faculty Publications

BACKGROUND: Neuroinflammation contributes to the pathophysiology of acute CNS injury, including traumatic brain injury (TBI). Although prostaglandin lipid mediators of inflammation contribute to a variety of inflammatory responses, their importance in neuroinflammation is not clear. There are conflicting reports as to the efficacy of inhibiting the enzymes required for prostaglandin formation, cyclooxygenase (COX) -1 and COX-2, for improving outcomes following TBI. The purpose of the current study was to determine the role of the COX isoforms in contributing to pathological processes resulting from TBI by utilizing mice deficient in COX-1 or COX-2.

RESULTS: Following a mild controlled cortical impact injury, …

Muc1 Is A Downstream Target Of Stat3 And Regulates Lung Cancer Cell Survival And Invasion, Jingchun Gao, Matthew J. Mcconnell, Bin Yu, Jiannong Li, Justin M. Balko, Esther P. Black, Joseph O. Johnson, Mark C. Lloyd, Soner Altiok, Eric B. Haura

Pharmaceutical Sciences Faculty Publications

Signal transducer and activator of transcription 3 (STAT3) is aberrantly activated in human cancer including lung cancer and has been implicated in transformation, tumorigenicity, and metastasis. One putative downstream gene regulated by Stat3 is MUC1 which also has important roles in tumorigenesis. We determined if Stat3 regulates MUC1 in lung cancer cell lines and what function MUC1 plays in lung cancer cell biology. We examined MUC1 expression in non-small cell lung cancer (NSCLC) cell lines and found high levels of MUC1 protein expression associated with higher levels of tyrosine phosphorylated STAT3. STAT3 knockdown downregulated MUC1 expression whereas constitutive STAT3 expression …

A Gene Expression Predictor Of Response To Egfr-Targeted Therapy Stratifies Progression-Free Survival To Cetuximab In Kras Wild-Type Metastatic Colorectal Cancer, Justin M. Balko, Esther P. Black

Pharmaceutical Sciences Faculty Publications

BACKGROUND: The anti-EGFR monoclonal antibody cetuximab is used in metastatic colorectal cancer (CRC), and predicting responsive patients garners great interest, due to the high cost of therapy. Mutations in the KRAS gene occur in ~40% of CRC and are a negative predictor of response to cetuximab. However, many KRAS-wildtype patients do not benefit from cetuximab. We previously published a gene expression predictor of sensitivity to erlotinib, an EGFR inhibitor. The purpose of this study was to determine if this predictor could identify KRAS-wildtype CRC patients who will benefit from cetuximab therapy.

METHODS: Microarray data from 80 metastatic CRC patients subsequently …

Role Of The Genomics Revolution In Pharmaceutics, Daniel A. Brazeau, Gayle A. Brazeau

Pharmaceutical Sciences Faculty Publications

Highlights the examples of Thiopurine S-methyltransferase (TPMT) and Warfarin as a means of describing some of the problems that are common to many pharmacogenetic cases. The pharmacogenetic literature contains many examples of confusing, or even contradictory, studies that arise due to unknown environmental factors that result in poor outcomes; drugs whose metabolism/transport are affected by multiple genes in multiple pathways; and clinically important genes that have many rare allelic variants with similar phenotypes variation in the frequencies of allelic variants among ethnic groups that mask the role of any one variant. These issues are common to most gene/drug dynamics and …

Carbon Nanotube Membranes For Use In The Transdermal Treatment Of Nicotine Addiction And Opioid Withdrawal Symptoms, Caroline L. Strasinger, Nicole N. Scheff, Ji Wu, Bruce J. Hinds, Audra L. Stinchcomb

Pharmaceutical Sciences Faculty Publications

Transdermal systems are attractive methods of drug administration specifically when treating patients for drug addiction. Current systems however are deficient in therapies that allow variable flux values of drug, such as nicotine for smoking cessation or complex dosing regimens using clonidine when treating opioid withdrawal symptoms. Through the use of functionalized carbon nanotube (CNT) membranes, drug delivery to the skin can be controlled by applying a small electrical bias to create a programmable drug delivery system. Clearly, a transdermal patch system that can be tailored to an individual's needs will increase patient compliance as well as provide much more efficient …

Identification Of A Potent Herbal Molecule For The Treatment Of Breast Cancer, Srinivas Koduru, Srinivasan Sowmyalakshmi, Raj Kumar, Rohini Gomathinayagam, Jürgen Rohr, Chendil Damodaran

Pharmaceutical Sciences Faculty Publications

BACKGROUND: Breast cancer (BCa)-related mortality still remains the second leading cause of cancer-related deaths worldwide. Patients with BCa have increasingly shown resistance and high toxicity to current chemotherapeutic drugs for which identification of novel targeted therapies are required.

METHODS: To determine the effect of PDBD on BCa cells, estrogen-receptor positive (ER+)-MCF-7 and estrogen-receptor negative (ER-)-MDA 231 cells were treated with PDBD and the cell viability, apoptotic, cell cycle, Western blot and Promoter assays were performed.

RESULTS: PDBD inhibits cell viability of ER+ and ER- BCa cells by inducing apoptosis without causing significant toxicity in normal breast epithelial cells. While dissecting …

The Challenge Of Educating In A Highly-Connected And Multitasking World, Daniel A. Brazeau, Gayle A. Brazeau

Pharmaceutical Sciences Faculty Publications

Today’s students are more connected and more integrated with their world than any past generation and information is readily available today from a multitude of sources. To what extent have these advances improved our students’ ability to become learned pharmacy professionals who are informed not only of the current world and its events but the profession itself?

Aluminum Bioavailability From Tea Infusion, Robert A. Yokel, Rebecca L. Florence

Pharmaceutical Sciences Faculty Publications

The objective was to estimate oral Al bioavailability from tea infusion in the rat, using the tracer ²⁶Al. ²⁶Al citrate was injected into tea leaves. An infusion was prepared from the dried leaves and given intra-gastrically to rats which received concurrent intravenous ²⁷Al infusion. Oral Al bioavailability (F) was calculated from the area under the ²⁶Al, compared to ²⁷Al, serum concentration × time curves. Bioavailability from tea averaged 0.37%; not significantly different from water (F = 0.3%), or basic sodium aluminum phosphate (SALP) in cheese (F = 0.1 to 0.3%), but greater than acidic SALP …

Manufactured Aluminum Oxide Nanoparticles Decrease Expression Of Tight Junction Proteins In Brain Vasculature, Lei Chen, Robert A. Yokel, Bernhard Hennig, Michal Toborek

Pharmaceutical Sciences Faculty Publications

Manufactured nanoparticles of aluminum oxide (nano-alumina) have been widely used in the environment; however, their potential toxicity provides a growing concern for human health. The present study focuses on the hypothesis that nano-alumina can affect the blood-brain barrier and induce endothelial toxicity. In the first series of experiments, human brain microvascular endothelial cells (HBMEC) were exposed to alumina and control nanoparticles in dose- and time-responsive manners. Treatment with nano-alumina markedly reduced HBMEC viability, altered mitochondrial potential, increased cellular oxidation, and decreased tight junction protein expression as compared to control nanoparticles. Alterations of tight junction protein levels were prevented by cellular …

Aluminum Bioavailability From Basic Sodium Aluminum Phosphate, An Approved Food Additive Emulsifying Agent, Incorporated In Cheese, Robert A. Yokel, Clair L. Hicks, Rebecca L. Florence

Pharmaceutical Sciences Faculty Publications

Oral aluminum (Al) bioavailability from drinking water has been previously estimated, but there is little information on Al bioavailability from foods. It was suggested that oral Al bioavailability from drinking water is much greater than from foods. The objective was to further test this hypothesis. Oral Al bioavailability was determined in the rat from basic [26Al]-sodium aluminum phosphate (basic SALP) in a process cheese. Consumption of approximately 1g cheese containing 1.5% or 3% basic SALP resulted in oral Al bioavailability (F) of approximately 0.1% and 0.3%, respectively, and time to maximum serum 26Al concentration (Tmax) of 8-9h. These Al bioavailability …

The Influence Of Citrate, Maltolate And Fluoride On The Gastrointestinal Absorption Of Aluminum At A Drinking Water-Relevant Concentration: A 26Al And 14C Study, Yuzhao Zhou, Wesley R. Harris, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

The objectives were to test the null hypotheses that (1) citrate, maltolate, and fluoride do not significantly influence oral Al bioavailability, C_max or T_max at an Al dose relevant to drinking water exposure; and (2) Al citrate and maltolate are absorbed intact from the gastrointestinal tract. Male Fisher rats were given 1 ml of solution intra-gastrically containing 1 nCi ²⁶Al (65 nmol total Al) as the Al³⁺ ion, or as complexes with ¹⁴C-citrate, ¹⁴C-maltolate or fluoride, during concurrent ²⁷Al iv infusion. Blood was repeatedly collected for serum ²⁶Al, total Al and ^{14 …}

Phase I And Phase Ii Ocular Metabolic Activities And The Role Of Metabolism In Ophthalmic Prodrug And Codrug Design And Delivery, Abeer M. Al-Ghananeem, Peter A. Crooks

Pharmaceutical Sciences Faculty Publications

While the mammalian eye is seldom considered an organ of drug metabolism, the capacity for biotransformation is present. Compared to the liver, the metabolic capabilities of the eye are minuscule; however, phase I and phase II metabolic activities have been detected in various ocular structures. The careful consideration of ocular tissue metabolic processes within the eye has important implications for controlling the detoxification of therapeutic agents and for providing the potential for site-specific bio-activation of certain drug molecules, thus enabling significant improvements in drug efficacy and the minimization of side-effect from either local or systemic drug delivery to the eye. …

Human Health Risk Assessment For Aluminium, Aluminium Oxide, And Aluminium Hydroxide, Daniel Krewski, Robert A. Yokel, Evert Nieboer, David Borchelt, Joshua Cohen, Jean Harry, Sam Kacew, Joan Lindsay, Amal M. Mahfouz, Virginie Rondeau

Pharmaceutical Sciences Faculty Publications

A compendium is provided of aluminium compounds used in industrial settings, and as pharmaceuticals, food additives, cosmetics and as other household products. Most aluminium compounds are solids exhibiting high melting points. The solubility of aluminium salts is governed by pH, because the aluminium(III)-cation (Al³⁺) has a strong affinity for the hydroxide ion, which promotes precipitation. Like Mg²⁺ and Ca²⁺ ions, Al³⁺ in most situations seeks out complexing agents with oxygen-atom donor sites such as carboxylate and phosphate groups, including in biological systems. Aluminium oxides, hydroxides and oxyhydroxides occur in numerous crystallographic forms, which exhibit different …

Aluminum Bioavailability From The Approved Food Additive Leavening Agent Acidic Sodium Aluminum Phosphate, Incorporated Into A Baked Good, Is Lower Than From Water, Robert A. Yokel, Rebecca L. Florence

Pharmaceutical Sciences Faculty Publications

There are estimates of oral aluminum (Al) bioavailability from drinking water, but little information on Al bioavailability from foods. Foods contribute ∼95% and drinking water 1–2% of the typical human's daily Al intake. The objectives were to estimate oral Al bioavailability from a representative food containing the food additive acidic sodium aluminum phosphate (acidic SALP), a leavening agent in baked goods. Rats were acclimated to a special diet that resulted in no stomach contents 14 h after its withdrawal. They were trained to rapidly consume a biscuit containing 1.5% acidic SALP. Oral Al bioavailability was then determined from a biscuit …

The Speciation Of Metals In Mammals Influences Their Toxicokinetics And Toxicodynamics And Therefore Human Health Risk Assessment, Robert A. Yokel, Stephen M. Lasley, David C. Dorman

Pharmaceutical Sciences Faculty Publications

Chemical form (i.e., species) can influence metal toxicokinetics and toxicodynamics and should be considered to improve human health risk assessment. Factors that influence metal speciation (and examples) include: (1) carrier-mediated processes for specific metal species (arsenic, chromium, lead and manganese), (2) valence state (arsenic, chromium, manganese and mercury), (3) particle size (lead and manganese), (4) the nature of metal binding ligands (aluminum, arsenic, chromium, lead, and manganese), (5) whether the metal is an organic versus inorganic species (arsenic, lead, and mercury), and (6) biotransformation of metal species (aluminum, arsenic, chromium, lead, manganese and mercury). The influence of speciation on metal …

The Chemical Species Of Aluminum Influences Its Paracellular Flux Across And Uptake Into Caco-2 Cells, A Model Of Gastrointestinal Absorption, Yuzhao Zhou, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

Aluminum (Al) can cause neurotoxicity, a low-turnover osteomalacia, and microcytic anemia. To test the null hypothesis that the chemical form (species) of Al does not influence its mechanism or rate of absorption from the gastrointestinal tract, Al flux across and uptake into Caco-2 cells was investigated. Caco-2 cells were grown on porous membranes mounted in vertical diffusion chambers or in 35-mm-diameter plastic cell culture dishes. When 8 mM ²⁷Al was introduced as the ion, citrate, maltolate, fluoride, or hydroxide, the apical to basolateral apparent permeability (P_app) of Al correlated highly with the P_app of lucifer yellow …

Manganese Distribution Across The Blood-Brain Barrier. Iv. Evidence For Brain Influx Through Store-Operated Calcium Channels, Janelle S. Crossgrove, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

Manganese (Mn) is a required co-factor for many ubiquitous enzymes; however, chronic Mn overexposure can cause manganism, a parkinsonian-like syndrome. Previous studies showed Mn influx into brain is carrier-mediated, though the putative carrier(s) were not established. Studies conducted with cultured bovine brain microvascular endothelial cells (bBMECs), which comprise the blood–brain barrier, revealed ⁵⁴Mn (II) uptake positively correlated with pH, was temperature-dependent, and was sodium- and energy-independent. Brain ⁵⁴Mn uptake correlated inversely with calcium (Ca) concentration, but ⁴⁵Ca uptake was unaltered by high Mn concentration. Lanthanum (La), a non-selective inhibitor of several Ca channel types, as well as …

26Al-Containing Acidic And Basic Sodium Aluminum Phosphate Preparation And Use In Studies Of Oral Aluminum Bioavailability From Foods Utilizing 26Al As An Aluminum Tracer, Robert A. Yokel, Aaron A. Urbas, Robert A. Lodder, John P. Selegue, Rebecca L. Florence

Pharmaceutical Sciences Faculty Publications

We synthesized ²⁶Al-containing acidic and basic (alkaline) sodium aluminum phosphates (SALPs) which are FDA-approved leavening and emulsifying agents, respectively, and used them to determine the oral bioavailability of aluminum incorporated in selected foods. We selected applicable methods from published syntheses (patents) and scaled them down (∼3000- and 850-fold) to prepare ∼300–400 mg of each SALP. The ²⁶Al was incorporated at the beginning of the syntheses to maximize ²⁶Al and ²⁷Al equilibration and incorporate the ²⁶Al in the naturally-occurring Al-containing chemical species of the products. Near infrared spectroscopy (NIR) and X-ray powder diffraction (XRD) were used …

Aluminium Content Of Some Foods And Food Products In The Usa, With Aluminium Food Additives, Salim M. Saiyed, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

The primary objective was to determine the aluminium (Al) content of selected foods and food products in the USA which contain Al as an approved food additive. Intake of Al from the labeled serving size of each food product was calculated. The samples were acid or base digested and analysed for Al using electrothermal atomic absorption spectrometry. Quality control (QC) samples, with matrices matching the samples, were generated and used to verify the Al determinations. Food product Al content ranged from < 1–27,000 mg kg⁻¹. Cheese in a serving of frozen pizzas had up to 14 mg of Al, from basic sodium …

Manganese Distribution Across The Blood-Brain Barrier. I. Evidence For Carrier-Mediated Influx Of Managanese Citrate As Well As Manganese And Manganese Transferrin, Janelle S. Crossgrove, David D. Allen, Bonny L. Bukaveckas, Susan S. Rhineheimer, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

Manganese (Mn) is an essential element and a neurotoxicant. Regulation of Mn movement across the blood–brain barrier (BBB) contributes to whether the brain Mn concentration is functional or toxic. In plasma, Mn associates with water, small molecular weight ligands and proteins. Mn speciation may influence the kinetics of its movement through the BBB. In the present work, the brain influx rates of ⁵⁴Mn²⁺, ⁵⁴Mn citrate and ⁵⁴Mn transferrin (⁵⁴Mn Tf) were determined using the in situ brain perfusion technique. The influx rates were compared to their predicted diffusion rates, which were determined from …

Brain Uptake, Retention, And Efflux Of Aluminum And Manganese, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

My colleagues and I investigated the sites and mechanisms of aluminum (Al) and manganese (Mn) distribution through the blood-brain barrier (BBB). Microdialysis was used to sample non-protein-bound Al in the extracellular fluid (ECF) of blood (plasma) and brain. Brain ECF Al appearance after intravenous Al citrate injection was too rapid to attribute to diffusion or to transferrin-receptor-mediated endocytosis, suggesting another carrier-mediated process. The brain:blood ECF Al concentration ratio was 0.15 at constant blood and brain ECF Al concentrations, suggesting carrier-mediated brain Al efflux. Pharmacological manipulations suggested the efflux carrier might be a monocarboxylate transporter (MCT). However, the lack of Al …