PROTACs Targeting BRM (SMARCA2) Afford Selective In Vivo Degradation over BRG1 (SMARCA4) and Are Active in BRG1 Mutant Xenograft Tumor Models

The identification of VHL-binding proteolysis targeting chimeras (PROTACs) that potently degrade the BRM protein (also known as SMARCA2) in SW1573 cell-based experiments is described. These molecules exhibit between 10- and 100-fold degradation selectivity for BRM over the closely related paralog protein BRG1 (SMARCA4). They also selectively impair the proliferation of the H1944 "BRG1-mutant" NSCLC cell line, which lacks functional BRG1 protein and is thus highly dependent on BRM for growth, relative to the wild-type Calu6 line. In vivo experiments performed with a subset of compounds identified PROTACs that potently and selectively degraded BRM in the Calu6 and/or the HCC2302 BRG1 mutant NSCLC xenograft models and also afforded antitumor efficacy in the latter system. Subsequent PK/PD analysis established a need to achieve strong BRM degradation (>95%) in order to trigger meaningful antitumor activity in vivo. Intratumor quantitation of mRNA associated with two genes whose transcription was controlled by BRM (PLAU and KRT80) also supported this conclusion.

Selective PROTAC-mediated degradation of SMARCA2 is efficacious in SMARCA4 mutant cancers

The mammalian SWItch/Sucrose Non-Fermentable (SWI/SNF) helicase SMARCA4 is frequently mutated in cancer and inactivation results in a cellular dependence on its paralog, SMARCA2, thus making SMARCA2 an attractive synthetic lethal target. However, published data indicates that achieving a high degree of selective SMARCA2 inhibition is likely essential to afford an acceptable therapeutic index, and realizing this objective is challenging due to the homology with the SMARCA4 paralog. Herein we report the discovery of a potent and selective SMARCA2 proteolysis-targeting chimera molecule (PROTAC), A947. Selective SMARCA2 degradation is achieved in the absence of selective SMARCA2/4 PROTAC binding and translates to potent in vitro growth inhibition and in vivo efficacy in SMARCA4 mutant models, compared to wild type models. Global ubiquitin mapping and proteome profiling reveal no unexpected off-target degradation related to A947 treatment. Our study thus highlights the ability to transform a non-selective SMARCA2/4-binding ligand into a selective and efficacious in vivo SMARCA2-targeting PROTAC, and thereby provides a potential new therapeutic opportunity for patients whose tumors contain SMARCA4 mutations.

The Discovery of GSK3640254, a Next-Generation Inhibitor of HIV-1 Maturation

GSK3640254 is an HIV-1 maturation inhibitor (MI) that exhibits significantly improved antiviral activity toward a range of clinically relevant polymorphic variants with reduced sensitivity toward the second-generation MI GSK3532795 (BMS-955176). The key structural difference between GSK3640254 and its predecessor is the replacement of the para-substituted benzoic acid moiety attached at the C-3 position of the triterpenoid core with a cyclohex-3-ene-1-carboxylic acid substituted with a CH2F moiety at the carbon atom α- to the pharmacophoric carboxylic acid. This structural element provided a new vector with which to explore structure-activity relationships (SARs) and led to compounds with improved polymorphic coverage while preserving pharmacokinetic (PK) properties. The approach to the design of GSK3640254, the development of a synthetic route and its preclinical profile are discussed. GSK3640254 is currently in phase IIb clinical trials after demonstrating a dose-related reduction in HIV-1 viral load over 7-10 days of dosing to HIV-1-infected subjects.

Abstract 5687: Selective, chemically-induced degradation of BRM (SMARCA2) enables in vivo efficacy in BRG1 (SMARCA4)-deficient xenograft tumor models

The mammalian SWI/SNF complex catalyzes the remodeling of chromatin through the helicase activity of two mutually-exclusive, paralogous subunits, BRG1 and BRM. BRG1 is frequently mutated in cancer and its inactivation results in a cellular dependence on BRM. Despite the attractiveness of BRM as a synthetic lethal therapeutic target, the selective inhibition of BRM represents a considerable challenge due to the high degree of homology between BRM and BRG1. Furthermore, published data indicate that achieving such selectivity is likely essential to afford an acceptable therapeutic index. We sought to mimic the synthetic lethality observed in BRG1-mutant cancers by identifying proteolysis-targeting chimera (PROTAC®) molecules capable of selectively degrading BRM via trimeric complex formation with the von Hippel-Lindau (VHL) E3 ligase. In this disclosure, we report our initial discovery of potent and selective chimeric BRM-degrader molecules which exhibit BRM DC50 values <1 nM and BRG1/BRM DC50 ratios >25. Importantly, selective BRM degradation can be achieved in the absence of selective PROTAC® binding (BRG1/BRM Kd ratios <2). Global ubiquitin mapping and proteome profiling reveal no unexpected off-target activity of the selective BRM PROTAC® degraders. Treatment of a panel of NSCLC cell lines with a representative degrader molecule resulted in enhanced growth inhibition in BRG1-mutant relative to BRG1-wild-type cell lines. We also demonstrate that intermittent intravenous administration of an optimized BRM PROTAC® degrader exhibited strong in vivo modulation of pharmacodynamic biomarkers and afforded tumor growth inhibition in several BRG1-mutant xenograft models. Our study thus highlights the ability to transform a non-selective BRM-binding ligand into a selective and efficacious in vivo BRM PROTAC® degrader.

Citation Format: Michael Berlin, Jennifer Cantley, Jing Wang, Mark Bookbinder, Gregory Cadelina, Emily Chan, Huifen Chen, Xin Chen, Kim Davenport, Tharu Fernando, Debbie Gordon, Brian Hamman, Roy Haskell, Alexey Ishchenko, Donald S. Kirkpatrick, Jonathan Maher, Mark Merchant, John Moffat, Alicia Morgan, An Nguyen, Jennifer Pizzano, Connor Quinn, Christopher M. Rose, Emma Rousseau, Vijay Sethuraman, Leanna Staben, Catherine Wilson, Xiaofen Ye, Fabio Broccatelli, Robert Yauch, Peter S. Dragovich. Selective, chemically-induced degradation of BRM (SMARCA2) enables in vivo efficacy in BRG1 (SMARCA4)-deficient xenograft tumor models [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5687.

Tunable Two-Compartment On-Demand Sustained Drug Release Based on Lipid Gels

The binary-lipid system of soybean phosphatidylcholine (SPC) and glycerol dioleate (GDO) can hydrate to gels on contacting with aqueous mediums, which has emerged as a versatile and promising delivery matrix for extended drug release applications. In the present work, we have characterized the gelation process of this SPC/GDO lyotropic gel (SGLG) system by rheology and evaluated the drug release profiles from the SGLG formulations with different SPC/GDO mass ratios. Our study has demonstrated that simply adjusting the SPC/GDO mass ratio can tune the lipid gelation behavior and modulate the drug release profiles. More importantly, the drug release from the SGLG formulations follows a two-compartment (fast and slow release compartments) release kinetics that has not been reported before. We posit that the fast release compartment corresponds to the passive diffusion of the drug during the early stage of the gel formation. After the boundary gel phase generation, the drug release is then dominated by the slow diffusion process from SGLG. The pharmacokinetic studies in rats match well with the in vitro studies, suggesting that the binary-lipid formulation is an excellent candidate for on-demand sustained drug delivery system.

Linking (Pyr)1apelin-13 pharmacokinetics to efficacy: Stabilization and measurement of a high clearance peptide in rodents

Apelin, the endogenous ligand for the APJ receptor, has generated interest due to its beneficial effects on the cardiovascular system. Synthesized as a 77 amino acid preproprotein, apelin is post-translationally cleaved to a series of shorter peptides. Though (Pyr)¹apelin-13 represents the major circulating form in plasma, it is highly susceptible to proteolytic degradation and has an extremely short half-life, making it challenging to quantify. Literature reports of apelin levels in rodents have historically been determined with commercial ELISA kits which suffer from a lack of selectivity, recognizing a range of active and inactive isoforms of apelin peptide. (Pyr)¹apelin-13 has demonstrated beneficial hemodynamic effects in humans, and we wished to evaluate if similar effects could be measured in pre-clinical models. Despite development of a highly selective LC/MS/MS method, in rodent studies where (Pyr)¹apelin-13 was administered exogenously the peptide was not detectable until a detailed stabilization protocol was implemented during blood collection. Further, the inherent high clearance of (Pyr)¹apelin-13 required an extended release delivery system to enable chronic dosing. The ability to deliver sustained doses and stabilize (Pyr)¹apelin-13 in plasma allowed us to demonstrate for the first time the link between systemic concentration of apelin and its pharmacological effects in animal models.

Structure-Property Basis for Solving Transporter-Mediated Efflux and Pan-Genotypic Inhibition in HCV NS5B Inhibitors

In solving the P-gp and BCRP transporter-mediated efflux issue in a series of benzofuran-derived pan-genotypic palm site inhibitors of the hepatitis C virus NS5B replicase, it was found that close attention to physicochemical properties was essential. In these compounds, where both molecular weight (MW >579) and TPSA (>110 Ų) were high, attenuation of polar surface area together with weakening of hydrogen bond acceptor strength of the molecule provided a higher intrinsic membrane permeability and more desirable Caco-2 parameters, as demonstrated by trifluoroacetamide 11 and the benchmark N-ethylamino analog 12. In addition, the tendency of these inhibitors to form intramolecular hydrogen bonds potentially contributes favorably to the improved membrane permeability and absorption. The functional group minimization that resolved the efflux problem simultaneously maintained potent inhibitory activity toward a gt-2 HCV replicon due to a switching of the role of substituents in interacting with the Gln414 binding pocket, as observed in gt-2a NS5B/inhibitor complex cocrystal structures, thus increasing the efficiency of the optimization. Noteworthy, a novel intermolecular S=O···C=O n → π* type interaction between the ligand sulfonamide oxygen atom and the carbonyl moiety of the side chain of Gln414 was observed. The insights from these structure-property studies and crystallography information provided a direction for optimization in a campaign to identify second generation pan-genotypic NS5B inhibitors.

Design, Synthesis, and SAR of C-3 Benzoic Acid, C-17 Triterpenoid Derivatives. Identification of the HIV-1 Maturation Inhibitor 4-((1 R,3a S,5a R,5b R,7a R,11a S,11b R,13a R,13b R)-3a-((2-(1,1-Dioxidothiomorpholino)ethyl)amino)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1 H-cyclopenta[ a]chrysen-9-yl)benzoic Acid (GSK3532795, BMS-955176)

GSK3532795, formerly known as BMS-955176 (1), is a potent, orally active, second-generation HIV-1 maturation inhibitor (MI) that advanced through phase IIb clinical trials. The careful design, selection, and evaluation of substituents appended to the C-3 and C-17 positions of the natural product betulinic acid (3) was critical in attaining a molecule with the desired virological and pharmacokinetic profile. Herein, we highlight the key insights made in the discovery program and detail the evolution of the structure-activity relationships (SARs) that led to the design of the specific C-17 amine moiety in 1. These modifications ultimately enabled the discovery of 1 as a second-generation MI that combines broad coverage of polymorphic viruses (EC₅₀ <15 nM toward a panel of common polymorphisms representative of 96.5% HIV-1 subtype B virus) with a favorable pharmacokinetic profile in preclinical species.

Moisture-Induced Amorphous Phase Separation of Amorphous Solid Dispersions: Molecular Mechanism, Microstructure, and Its Impact on Dissolution Performance

Amorphous phase separation (APS) is commonly observed in amorphous solid dispersions (ASD) when exposed to moisture. The objective of this study was to investigate: (1) the phase behavior of amorphous solid dispersions composed of a poorly water-soluble drug with extremely low crystallization propensity, BMS-817399, and PVP, following exposure to different relative humidity (RH), and (2) the impact of phase separation on the intrinsic dissolution rate of amorphous solid dispersion. Drug-polymer interaction was confirmed in ASDs at different drug loading using infrared (IR) spectroscopy and water vapor sorption analysis. It was found that the drug-polymer interaction could persist at low RH (≤75% RH) but was disrupted after exposure to high RH, with the advent of phase separation. Surface morphology and composition of 40/60 ASD at micro-/nano-scale before and after exposure to 95% RH were also compared. It was found that hydrophobic drug enriched on the surface of ASD after APS. However, for the 40/60 ASD system, the intrinsic dissolution rate of amorphous drug was hardly affected by the phase behavior of ASD, which may be partially attributed to the low crystallization tendency of amorphous BMS-817399 and enriched drug amount on the surface of ASD. Intrinsic dissolution rate of PVP decreased resulting from APS, leading to a lower concentration in the dissolution medium, but supersaturation maintenance was not anticipated to be altered after phase separation due to the limited ability of PVP to inhibit drug precipitation and prolong the supersaturation of drug in solution. This study indicated that for compounds with low crystallization propensity and high hydrophobicity, the risk of moisture-induced APS is high but such phase separation may not have profound impact on the drug dissolution performance of ASDs. Therefore, application of ASD technology on slow crystallizers could incur low risks not only in physical stability but also in dissolution performance.

Discovery of a Hepatitis C Virus NS5B Replicase Palm Site Allosteric Inhibitor (BMS-929075) Advanced to Phase 1 Clinical Studies

The hepatitis C virus (HCV) NS5B replicase is a prime target for the development of direct-acting antiviral drugs for the treatment of chronic HCV infection. Inspired by the overlay of bound structures of three structurally distinct NS5B palm site allosteric inhibitors, the high-throughput screening hit anthranilic acid 4, the known benzofuran analogue 5, and the benzothiadiazine derivative 6, an optimization process utilizing the simple benzofuran template 7 as a starting point for a fragment growing approach was pursued. A delicate balance of molecular properties achieved via disciplined lipophilicity changes was essential to achieve both high affinity binding and a stringent targeted absorption, distribution, metabolism, and excretion profile. These efforts led to the discovery of BMS-929075 (37), which maintained ligand efficiency relative to early leads, demonstrated efficacy in a triple combination regimen in HCV replicon cells, and exhibited consistently high oral bioavailability and pharmacokinetic parameters across preclinical animal species. The human PK properties from the Phase I clinical studies of 37 were better than anticipated and suggest promising potential for QD administration.

Lipophilic salts of poorly soluble compounds to enable high-dose lipidic SEDDS formulations in drug discovery

Self-emulsifying drug delivery systems (SEDDS) have been used to solubilize poorly water-soluble drugs to improve exposure in high-dose pharmacokinetic (PK) and toxicokinetic (TK) studies. However, the absorbable dose is often limited by drug solubility in the lipidic SEDDS vehicle. This study focuses on increasing solubility and drug loading of ionizable drugs in SEDDS vehicles using lipophilic counterions to prepare lipophilic salts of drugs. SEDDS formulations of two lipophilic salts-atazanavir-2-naphthalene sulfonic acid (ATV-2-NSA) and atazanavir-dioctyl sulfosuccinic acid (ATV-Doc)-were characterized and their performance compared to atazanavir (ATV) free base formulated as an aqueous crystalline suspension, an organic solution, and a SEDDS suspension, using in vitro, in vivo, and in silico methods. ATV-2-NSA exhibited ∼6-fold increased solubility in a SEDDS vehicle, allowing emulsion dosing at 12mg/mL. In rat PK studies at 60mg/kg, the ATV-2-NSA SEDDS emulsion had comparable exposure to the free-base solution, but with less variability, and had better exposure at high dose than aqueous suspensions of ATV free base. Trends in dose-dependent exposure for various formulations were consistent with GastroPlus™ modeling. Results suggest use of lipophilic salts is a valuable approach for delivering poorly soluble compounds at high doses in Discovery.

Sodium Lauryl Sulfate Competitively Interacts with HPMC-AS and Consequently Reduces Oral Bioavailability of Posaconazole/HPMC-AS Amorphous Solid Dispersion

Sodium lauryl sulfate (SLS), as an effective surfactant, is often used as a solubilizer and/or wetting agent in various dosage forms for the purpose of improving the solubility and dissolution of lipophilic, poorly water-soluble drugs. This study aims to understand the impact of SLS on the solution behavior and bioavailability of hypromellose acetate succinate (HPMC-AS)-based posaconazole (PSZ) ASDs, and to identify the underlying mechanisms governing the optimal oral bioavailability of ASDs when surfactants such as SLS are used in combination. Fluorescence spectroscopy and optical microscopy showed that "oil-out" or "liquid-liquid phase separation (LLPS)" occurred in the supersaturated PSZ solution once drug concentration surpassed ∼12 μg/mL, which caused the formation of drug-rich oily droplets with initial size of ∼300-400 nm. Although FT-IR study demonstrated the existence of specific interactions between PSZ and HPMC-AS in the solid state, predissolved HPMC-AS was unable to delay LLPS of the supersaturated PSZ solution and PSZ-rich amorphous precipitates with ∼16-18% HPMC-AS were formed within 10 min. The coprecipitated HPMC-AS was found to be able to significantly delay the crystallization of PSZ in the PSZ-rich amorphous phase from less than 10 min to more than 4 h, yet coexistent SLS was able to negate this crystallization inhibition effect of HPMC-AS in the PSZ-rich amorphous precipitates and cause fast PSZ crystallization within 30 min. 2D-NOESY and the CMC/CAC results demonstrated that SLS could assemble around HPMC-AS and competitively interact with HPMC-AS in the solution, thus prevent HPMC-AS from acting as an effective crystallization inhibitor. In a crossover dog PK study, this finding was found to be correlating well with the in vivo bioavailability of PSZ ASDs formulated with or without SLS. The SLS containing PSZ ASD formulation demonstrated an in vivo bioavailability ∼30% of that without SLS, despite the apparently better in vitro dissolution, which only compared the dissolved drug in solution, a small fraction of the total PSZ dose. We conclude that the bioavailability of ASDs is highly dependent on the molecular interactions between drug, surfactant, and polymer, not only in the solution phase but also in the drug-rich "oily" phase caused by supersaturation.

Discovery of BMS-955176, a Second Generation HIV-1 Maturation Inhibitor with Broad Spectrum Antiviral Activity

HIV-1 maturation inhibition (MI) has been clinically validated as an approach to the control of HIV-1 infection. However, identifying an MI with both broad polymorphic spectrum coverage and good oral exposure has been challenging. Herein, we describe the design, synthesis, and preclinical characterization of a potent, orally active, second generation HIV-1 MI, BMS-955176 (2), which is currently in Phase IIb clinical trials as part of a combination antiretroviral regimen.

Drug-polymer-water interaction and its implication for the dissolution performance of amorphous solid dispersions

The in vitro dissolution mechanism of an amorphous solid dispersion (ASD) remains elusive and highly individualized, yet rational design of ASDs with optimal performance and prediction of their in vitro/in vivo performance are very much desirable in the pharmaceutical industry. To this end, we carried out comprehensive investigation of various ASD systems of griseofulvin, felodipine, and ketoconazole, in PVP-VA or HPMC-AS at different drug loading. Physiochemical properties and processes related to drug-polymer-water interaction, including the drug crystallization tendency in aqueous medium, drug-polymer interaction before and after moisture exposure, supersaturation of drug in the presence of polymer, polymer dissolution kinetics, etc., were characterized and correlated with the dissolution performance of ASDs at different dose and different drug/polymer ratio. It was observed that ketoconazole/HPMC-AS ASD outperformed all other ASDs in various dissolution conditions, which was attributed to the drug's low crystallization tendency, the strong ketoconazole/HPMC-AS interaction and the robustness of this interaction against water disruption, the dissolution rate and the availability of HPMC-AS in solution, and the ability of HPMC-AS in maintaining ketoconazole supersaturation. It was demonstrated that all these properties have implications for the dissolution performance of various ASD systems, and further quantification of them could be used as potential predictors for in vitro dissolution of ASDs. For all ASDs investigated, HPMC-AS systems performed better than, or at least comparably with, their PVP-VA counterparts, regardless of the drug loading or dose. This observation cannot be solely attributed to the ability of HPMC-AS in maintaining drug supersaturation. We also conclude that, for fast crystallizers without strong drug-polymer interaction, the only feasible option to improve dissolution might be to lower the dose and the drug loading in the ASD. In this study, we implemented an ASD/water Flory-Huggins parameter plot, which might assist in revealing the physical nature of the drug-polymer interaction. We also introduced supersaturation parameter and dissolution performance parameter as two quantitative measurements to compare the abilities of polymers in maintaining drug supersaturation, and the dissolution performance of various solid dispersions, respectively.

Design and synthesis of 4-heteroaryl 1,2,3,4-tetrahydroisoquinolines as triple reuptake inhibitors

A series of 4-bicyclic heteroaryl 1,2,3,4-tetrahydroisoquinoline inhibitors of the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT) was discovered. The synthesis and structure-activity relationship (SAR) of these triple reuptake inhibitors (TRIs) will be discussed. Compound 10i (AMR-2), a very potent inhibitor of SERT, NET, and DAT, showed efficacy in the rat forced-swim and mouse tail suspension models with minimum effective doses of 0.3 and 1 mg/kg (po), respectively. At efficacious doses in these assays, 10i exhibited substantial occupancy levels at the three transporters in both rat and mouse brain. The study of the metabolism of 10i revealed the formation of a significant active metabolite, compound 13.

A systematic evaluation of solubility enhancing excipients to enable the generation of permeability data for poorly soluble compounds in Caco-2 model

The study presented here identified and utilized a panel of solubility enhancing excipients to enable the generation of flux data in the Human colon carcinoma (Caco-2) system for compounds with poor solubility. Solubility enhancing excipients Dimethyl acetamide (DMA) 1 % v/v, polyethylene glycol (PEG) 400 1% v/v, povidone 1% w/v, poloxamer 188 2.5% w/v and bovine serum albumin (BSA) 4% w/v did not compromise Caco-2 monolayer integrity as assessed by trans-epithelial resistance measurement (TEER) and Lucifer yellow (LY) permeation. Further, these excipients did not affect P-glycoprotein (P-gp) mediated bidirectional transport of digoxin, permeabilities of high (propranolol) or low permeability (atenolol) compounds, and were found to be inert to Breast cancer resistant protein (BCRP) mediated transport of cladribine. This approach was validated further using poorly soluble tool compounds, atazanavir (poloxamer 188 2.5% w/v) and cyclosporine A (BSA 4% w/v) and also applied to new chemical entity (NCE) BMS-A in BSA 4% w/v, for which Caco-2 data could not be generated using the traditional methodology due to poor solubility (<1 µM) in conventional Hanks balanced salt solution (HBSS). Poloxamer 188 2.5% w/v increased solubility of atazanavir by >8 fold whereas BSA 4% w/v increased the solubility of cyclosporine A and BMS-A by >2-4 fold thereby enabling permeability as well as efflux liability estimation in the Caco-2 model with reasonable recovery values. To conclude, addition of excipients such as poloxamer 188 2.5% w/v and BSA 4% w/v to HBSS leads to a significant improvement in the solubility of the poorly soluble compounds resulting in enhanced recoveries without modulating transporter-mediated efflux, expanding the applicability of Caco-2 assays to poorly soluble compounds.

Memory in aged mice is rescued by enhanced expression of the GluN2B subunit of the NMDA receptor

The GluN2B subunit of the N-methyl-d-aspartate (NMDA) receptor shows age-related declines in expression across the frontal cortex and hippocampus. This decline is strongly correlated to age-related memory declines. This study was designed to determine if increasing GluN2B subunit expression in the frontal lobe or hippocampus would improve memory in aged mice. Mice were injected bilaterally with either the GluN2B vector, containing cDNA specific for the GluN2B subunit and enhanced green fluorescent protein (eGFP); a control vector or vehicle. Spatial memory, cognitive flexibility, and associative memory were assessed using the Morris water maze. Aged mice, with increased GluN2B subunit expression, exhibited improved long-term spatial memory, comparable to young mice. However, memory was rescued on different days in the Morris water maze; early for hippocampal GluN2B subunit enrichment and later for the frontal lobe. A higher concentration of the GluN2B antagonist, Ro 25-6981, was required to impair long-term spatial memory in aged mice with enhanced GluN2B expression, as compared to aged controls, suggesting there was an increase in the number of GluN2B-containing NMDA receptors. In addition, hippocampal slices from aged mice with increased GluN2B subunit expression exhibited enhanced NMDA receptor-mediated excitatory post-synaptic potentials (EPSP). Treatment with Ro 25-6981 showed that a greater proportion of the NMDA receptor-mediated EPSP was due to the GluN2B subunit in these animals, as compared to aged controls. These results suggest that increasing the production of the GluN2B subunit in aged animals enhances memory and synaptic transmission. Therapies that enhance GluN2B subunit expression within the aged brain may be useful for ameliorating age-related memory declines.

Immunogold labeling to enhance contrast in optical coherence microscopy of tissue engineered corneal constructs

Our lab has used an optical coherence microscope (OCM) to assess both the structure of tissue-engineered corneal constructs and their transparency. Currently, we are not able to resolve cells versus collagen matrix material in the images produced. We would like to distinguish cells in order to determine if they are viable while growing in culture and also if they are significantly contributing to the light scattering in the tissue. In order to do this, we are currently investigating the use of immunogold labeling. Gold nanoparticles are high scatterers and can create contrast in images. We have conjugated gold nanoparticles to antibodies specific to the alpha/sub 5/beta/sub 1/ integrins expressed in some corneal cells. This choice of target should allow assessment of the phenotypic behavior of the cells in the tissue, as different integrins are expressed in different phenotypes. This study applies the immunogold technique to study cultured corneal cells using the OCM with the ultimate goal of monitoring cellular behavior in engineered tissue and corroborating results from standard histological methods.

An optical coherence microscope for 3-dimensional imaging in developmental biology

An optical coherence microscope (OCM) has been designed and constructed to acquire 3-dimensional images of highly scattering biological tissue. Volume-rendering software is used to enhance 3-D visualization of the data sets. Lateral resolution of the OCM is 5 mm (FWHM), and the depth resolution is 10 mm (FWHM) in tissue. The design trade-offs for a 3-D OCM are discussed, and the fundamental photon noise limitation is measured and compared with theory. A rotating 3-D image of a frog embryo is presented to illustrate the capabilities of the instrument.

Evaluation of the clinical LOINC (Logical Observation Identifiers, Names, and Codes) semantic structure as a terminology model for standardized assessment measures

OBJECTIVE

The purpose of this study was to test the adequacy of the Clinical LOINC (Logical Observation Identifiers, Names, and Codes) semantic structure as a terminology model for standardized assessment measures.

METHODS

After extension of the definitions, 1, 096 items from 35 standardized assessment instruments were dissected into the elements of the Clinical LOINC semantic structure. An additional coder dissected at least one randomly selected item from each instrument. When multiple scale types occurred in a single instrument, a second coder dissected one randomly selected item representative of each scale type.

RESULTS

The results support the adequacy of the Clinical LOINC semantic structure as a terminology model for standardized assessments. Using the revised definitions, the coders were able to dissect into the elements of Clinical LOINC all the standardized assessment items in the sample instruments. Percentage agreement for each element was as follows: component, 100 percent; property, 87.8 percent; timing, 82.9 percent; system/sample, 100 percent; scale, 92.6 percent; and method, 97.6 percent.

DISCUSSION

This evaluation was an initial step toward the representation of standardized assessment items in a manner that facilitates data sharing and re-use. Further clarification of the definitions, especially those related to time and property, is required to improve inter-rater reliability and to harmonize the representations with similar items already in LOINC.

Primary seminal vesicle carcinoma: an immunohistochemical analysis of four cases

Primary adenocarcinoma of the seminal vesicles is an extremely rare neoplasm. Because prompt diagnosis and treatment are associated with improved long-term survival, accurate recognition of this neoplasm is important, particularly when evaluating limited biopsy material. Immunohistochemistry can be used to rule out neoplasms that commonly invade the seminal vesicles, such as prostatic adenocarcinoma. Previous reports have shown that seminal vesicle adenocarcinoma (SVCA) is negative for prostate-specific antigen (PSA) and prostate-specific acid phosphatase (PAP); however, little else is known of its immunophenotype. Consequently, we evaluated the utility of cancer antigen 125 (CA-125) and cytokeratin (CK) subsets 7 and 20 for distinguishing SVCA from other neoplasms that enter the differential diagnosis. Four cases of SVCA-three cases of bladder adenocarcinoma and a rare case of adenocarcinoma arising in a mullerian duct cyst-were immunostained for CA-125, CK7, and CK20. Three of four cases of SVCA were CA-125 positive and CK7 positive. All four cases were CK20 negative. All bladder adenocarcinomas and the mullerian duct cyst adenocarcinoma were CK7 positive and negative for CA-125 and CK20. In addition, CA-125 immunostaining was performed in neoplasms that commonly invade the seminal vesicles, including prostatic adenocarcinoma (n = 40), bladder transitional cell carcinoma (n = 32), and rectal adenocarcinoma (n = 10), and all were negative for this antigen. In conclusion, the present study has shown that the CK7-positive, CK20-negative, CA-125-positive, PSA/PAP-negative immunophenotype of papillary SVCA is unique and can be used in conjunction with histomorphology to distinguish it from other tumors that enter the differential diagnosis, including prostatic adenocarcinoma (CA-125 negative, PSA/PAP positive), bladder transitional cell carcinoma (CK20 positive, CA-125 negative), rectal adenocarcinoma (CA-125 negative, CK7 negative, CK20 positive), bladder adenocarcinoma (CA-125 negative), and adenocarcinoma arising in a mullerian duct cyst (CA-125 negative).

Hypomagnesemia in trauma patients

The objective of this study was to determine the incidence of hypomagnesemia in injured patients (versus a general hospital cohort) and to compare total and ionized values with each other and with the incidence of injury severity and ethanol level. It was a descriptive study of consecutive injured patients at a level II trauma center. For 3 months subjects underwent admission paired analysis of blood total magnesium (TMg) and ionized magnesium (IMg). IMg was determined by microanalysis of whole blood (Nova Biomedical, NovaSP9). During the same time period, all hospital samples for TMg (m = 1308) underwent simultaneous IMg testing. Pearson correlation coefficients were determined for IMg versus TMg, Injury Severity Score (ISS), Trauma Score (TS), Glasgow Coma Scale (GCS), and blood units transfused. By convention, hypomagnesemia was defined as TMg < or =1.6 mg/dl and IMg < or = 0.5 mg/dl. Altogether 43% of 113 trauma patients had low magnesium levels compared to 30% of noninjured cohorts (p<0.05). The correlation coefficient (r(2)) for TMg and IMg was 0.74 for TMg values >1.6, but for TMg < or =1.6 the r(2) was 0.35. Coefficients for IMg and ISS, TS, GCS, units transfused, and ethanol level were 0.06, 0.08, 0.10, 0.04, and 0.01, respectively. Mean IMg was 0.57+/-0.09 mg/dl with ethanol ingestion and 0.56+/-0.06 mg/dl without ethanol ingestion (mean +/- SD, p>0.05). It was concluded that hypomagnesia is common in injured patients but does not correlate with indices of injury severity or ethanol level. TMg is not a good predictor of IMg at low levels. Trauma patients may benefit from determination of IMg for accurate diagnosis of a low Mg level to facilitate repletion.

UK National Third Molar project: the initial report

The National Third Molar (NTM) project was set up to assess current clinical practice in the UK concerning the management of third molar teeth. Patients were recruited from both hospital and general dental practice. During the one month study period 9248 patients with 26,577 third molars were recruited. In this report we present the findings in the 8298 patients with 25,001 third molars who were referred to hospital for assessment. Over half of all patients referred for assessment had either no extractions or a single third molar extracted. Less than a quarter of all patients referred underwent removal of all four third molars. Twenty per cent of all third molars assessed were not extracted. Of all lower third molars listed for extraction, 9574 (78%) were associated with symptoms or disease. Pericoronitis was the commonest indication for extraction and was cited in 39.5% of all extractions. Almost 70% of third molar extractions were done under general anaesthesia while less than a quarter were performed under local anaesthesia alone.

Recidivism in equestrian trauma

A 3-year chart survey and questionnaire was conducted of equestrian-injured patients at a regional trauma center to determine patterns and consequences of injury and rate of recidivism. Ninety-two patients (95 encounters) were treated; most were young (mean age, 27 +/- 11 years) women (84%) riders sustaining falls (80%). Most injuries were orthopedic (47%); 19 per cent of patients required hospital admission. There was one death. Helmet use was documented in only 34 per cent. Eighty-one per cent of patients responded to a follow-up telephone survey; 36 per cent recounted additional accidents (mean, 1.4 +/- 0.5). Mean time lost from work was 3 weeks, with 19 per cent reporting chronic disability. Mean annual hospital charges for the cohort were $88,925.00. Recidivism is common in equestrian trauma. Hospital charges are significant. Lost time from work is considerable, with one in five patients reporting long-term disability. Given the cost and disability incurred with equestrian trauma, efforts at injury prevention appear warranted.

Giant cell arteritis of the uterus: case report and review

We here report a rare case of giant cell arteritis (GCA) of the myometrium found incidentally in a 68-year-old Caucasian woman presenting with uterovaginal prolapse and a known past history of temporal arteritis/polymyalgia rheumatica. Histology revealed a segmental arteritis of small, medium and some quite large myometrial arteries with extensive destruction of both internal and external elastic laminae. Multinucleate giant cells, lymphocytes and histiocytes were most prominent in the inflammatory infiltrate. The findings in this case are compared with previous reports. In a review of the literature it was found that almost one third of cases presented with generalised symptoms such as fever, anemia, fatigue and weight loss. The symptoms were not immediately recognised as temporal arteritis or polymyalgia rheumatica. On routine physical examination or radiological investigation, benign gynecological pathology such as a simple ovarian cyst or uterine leiomyoma were found. The subsequent unexpected discovery of GCA on histological examination was the critical event in alerting clinicians to the diagnosis of temporal arteritis/polymyalgia rheumatica. Without exception steroid therapy was successful in achieving relief of generalised symptoms.

Bilateral primary seminal vesicle carcinoma

We report a rare case of bilateral primary seminal vesicle carcinoma in a 73 yr old Australian man. To our knowledge this case report is the 48th histologically confirmed case of primary seminal vesicle neoplasia and only the fourth reported case of primary bilateral seminal vesicle carcinoma. Macroscopically the tumor was localized to both seminal vesicles and the adjacent right lobe of the prostate. Histologically the tumor and metastases displayed a PSA, PAP and CEA negative, well differentiated papillary adenocarcinoma resembling the pattern of normal seminal vesicle epithelium. No other primary carcinoma in the body was demonstrated. The patient survived for 3 yrs and 4 mths without recurrence of tumor. The pathological criteria for acceptance of primary seminal vesicle carcinoma, difficulties in clinical/radiological detection of seminal vesicle tumors and CA-125 immunoreactivity are discussed.

An unusual intraosseous melanoma in the maxillary alveolus

A case is reported of a 31-year-old white man who presented with a solitary melanoma in the maxillary alveolus. The lesion was located between and had displaced the roots of the lateral incisor and canine and was relatively well circumscribed on radiography. No mucosal origin or potential primary lesion was found, and a marginal excision resulted in the patient remaining free from disease after 7 years of follow-up. Metastasis of melanoma to the jaws is rare even in disseminated disease, and this solitary lesion is unusual. Although metastasis from a regressed primary tumor cannot be excluded, some of the features raise the possibility that this melanoma may have arisen as a primary tumor within bone.

Oral presentation of minocycline-induced black bone disease

Minocycline hydrochloride is a semisynthetic tetracycline derivative used widely for the treatment of acne vulgaris. Among its side effects is the ability to pigment many tissues particularly thyroid, skin, tooth, and bone. A case is presented in which long-term minocycline therapy (500 g taken orally over 11 years) resulted in dark bone pigmentation (black bone disease) severe enough to be visible through the alveolar and palatal mucosa. No skin or tooth pigmentation was present.

Transfacial access for neurosurgical procedures: an extended role for the maxillofacial surgeon. I. The upper cervical spine and clivus

A variety of osteoplastic flaps have been devised for transoral or extraoral access to the base of skull and the upper anterior cervical spine. Part I of this two-part review will describe access to the clivus and upper anterior cervical spine. Part II will describe access to the middle cranial fossa, the infratemporal fossa and the pterygoid (retromaxillary) "space".

Transfacial access for neurosurgical procedures: an extended role for the maxillofacial surgeon. II. Middle cranial fossa, infratemporal fossa and pterygoid space

A variety of osteoplastic flaps have been devised for transoral or extraoral access to the base of skull and the upper anterior cervical spine. Part I of this two-part review describes access to the clivus and upper anterior cervical spine. Part II will describe access to the middle cranial fossa, the infratemporal fossa and the pterygoid (retromaxillary) "space".

Effect of altering heart rate on oxygen uptake at exercise onset

At the onset of exercise, both cardiac output and ventilation increase abruptly. We investigated the hypothesis that a rapid change in cardiac output, as effected by an immediate increase in heart rate at the start of exercise and a decrease in heart rate at the termination of exercise, affects the responses of oxygen uptake. Five patients in whom programmable pacemakers had been previously inserted for complete heart block were studied. Responses in ventilation and gas exchange were recorded breath by breath during studies in which each subject performed 16 transitions between rest and moderate exercise on a cycle ergometer. In a randomized fashion, in half of the transitions, heart rate was accelerated from a low rate to a high rate as exercise began; in the other half, heart rate was held constant at the low rate as exercise began. Oxygen uptake increased by 30 percent in the first 20 seconds of exercise, when heart rate was constrained, while it increased by 70 percent when heart rate was abruptly accelerated. Similarly, smaller changes were observed at the cessation of exercise when the heart rate was constrained, as compared to an abrupt decrease in heart rate. Despite this difference in the responses of oxygen uptake, at the transitions in exercise, the ventilatory responses were indistinguishable. We have demonstrated that ventilation-independent changes in oxygen uptake can be induced at the onset and cessation of exercise. These alterations in oxygen uptake are predictable from differences in blood flow which occur as a consequence of the differences in time course of the heart rate.

Zygomaticotemporal approach to the basis cranii and basilar artery

When using the zygomaticotemporal approach, one removes the whole of the zygomatic bone with its attachment to the masseter muscle, allowing a lower and more anterior approach to the interpeduncular cistern along the inferomedial surface of the temporal lobe. Minimal brain retraction is required to give an excellent view of the bifurcation of the basilar artery and of the suprasellar region.

Bullous lesions of the skin and mucous membranes in primary amyloidosis

Four cases of primary amyloidosis are described in which bullous lesions of the skin or oral mucosa were a prominent clinical feature. Biopsy of such lesions and demonstration of amyloid by special staining may be of great diagnostic help.