Repeat Evaluation of Lung Shunt Fraction is Unnecessary: A Retrospective Observational Study of Successive Lung Shunt Fractions from Variable Arterial Distributions in Patients Undergoing Radioembolization of Primary and Secondary Liver Tumors

PURPOSE

To evaluate whether the recalculation of lung shunt fraction (LSF) is necessary prior to next-stage or same lobe repeat radioembolization.

MATERIALS AND METHODS

Retrospective chart review was performed for patients who underwent radioembolization between February 2008 and December 2018. Eighty of 312 patients had repeat mapping angiograms and LSF calculations. A total of 160 LSF calculations were made using planar imaging (155, [97%]) and single-photon emission computed tomography (5 [3%]) technetium-99m macroaggregated albumin hepatic arterial injection imaging. The mean patient age was 61.8 years ± 12.7; 69 (86%) patients had metastatic disease and 11 (14%) had hepatocellular carcinoma.

RESULTS

Patients had a median LSF of 5% (interquartile range [IQR] 3%-9%) with a median absolute difference of 1.25 (IQR 0.65-3.4) and a median of 76 days (IQR 42.5-120 days) between repeat LSF calculations. There was a median change in LSF of 0.2% between mapping studies (P = .11). There was no statistical significance between the repeat LSFs regardless of the arterial distribution (P = .79) or between tumor types (P = .75). No patients exceeded lung dose limits using actual or predicted prescribed dose amounts. The actual median lung dose was 2.6 Gy (IQR 1.8-4.4 Gy, maximum = 20.5) for the first radioembolization and 2.0 Gy (IQR 1.3-3.7 Gy, maximum = 10.1) for the second radioembolization.

CONCLUSIONS

No significant difference in LSF was identified between different time points and arterial distributions within the same patient undergoing repeat radioembolization. In patients who receive well under 30-Gy lung dose for the initial treatment and a 50-Gy cumulative lung dose, repeat radioembolization treatments in the same patient may not require a repeat LSF calculation.

THU0219 FIRST-INHUMAN STUDY OF SAFETY, PHARMACOKINETICS AND PHARMACODYNAMICS OF IRAK1/4 INHIBITOR R835 IN HEALTHY SUBJECTS

Background:

Toll-Like Receptors (TLR) and Interleukin-1 Receptors (IL-1R) play a critical role in the innate immune response as microbial and tissue damage sensors, providing a bridge between the innate and adaptive immunity. Interleukin receptor associated kinases (IRAK) 1 and 4 are serine/threonine kinases that are essential for signaling downstream of most TLRs and IL-1Rs and the resulting production of pro-inflammatory cytokines. Suppression of TLR and IL-1R signaling through inhibition of IRAK1/4 kinases is a promising therapeutic approach for the treatment of inflammatory and autoimmune diseases. We have identified a potent and selective IRAK1/4 inhibitor (R835) that showed dose-dependent inhibition of lipopolysaccharide (LPS, a TLR4 agonist), and IL-1β induced serum cytokines in mice. R835 prevented disease onset and progression in multiple rodent models of inflammatory diseases, including arthritis and lupus models.

Objectives:

The aim of this FIH study was to characterize the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of R835 after single or multiple dose oral administrations.

Methods:

This study was a randomized, placebo-controlled, double-blind Phase 1 study in healthy subjects in three parts: single ascending doses (20 mg-1920 mg, Part A) with food effect in a separate cohort (480 mg), multiple ascending doses (120 mg and 960 mg, BID, Part B) with a caffeine interaction (960 mg cohort), and an intravenous LPS challenge test at 240 mg oral dose of R835 (Part C).

Results:

Single doses of up to 480 mg R835 in organic solution, single doses of up to 1920 mg R835 as capsule, multiple doses of 120 mg R835 Q12H (organic solution), and 960 mg R835 Q12H (capsule) were safe and well tolerated. All R835 related adverse events (AEs) were mild in intensity and reversible, and mostly associated with the higher doses of R835 in the organic solution. The most common AEs were headache and gastrointestinal disturbance. The PK of R835 was linear and dose proportional in exposure over the dose range studied. A nominal level of accumulation in plasma achieved rapidly upon repeated BID administrations with steady-state essentially attained in 2 days. A high-fat meal with the capsule formulation resulted in slow rate of absorption but had no effect on the extent of absorption. There was no effect of R835 on metabolism of caffeine (P450 CYP1A2 prototype substrate). In the LPS challenge test, R835 profoundly inhibited the acute release of cytokines, including TNF-α, IL-6, IL-8, MIP1α and MIP1β, but had no impact on CRP release.

Conclusion:

R835 was well tolerated after single or multiple dose administrations. The most common AEs were headache and gastrointestinal disturbance. For both of the formulations tested, the PK of R835 was linear and exposure was dose proportional with rapid steady-state attainment following BID administration. There was no drug-drug interaction by use of caffeine as the protype substrate. R835 inhibited the LPS induced release of cytokines in the serum, including TNF-α, IL-6, IL-8, MIP1α and MIP1β, mirroring preclinical data in mice. The desirable PK and safety profile combined with proof of mechanism, as demonstrated by inhibition of cytokine release, support progression of R835 into Phase II clinical development as an agent for the treatment of inflammatory and autoimmune diseases.

Disclosure of Interests: :

Lucy Yan Shareholder of: Amgen, Rigel, Employee of: Amgen, Rigel, Sandra Tong Shareholder of: Rigel, Employee of: Rigel, Anthony Absalom: None declared, Izaak den Daas: None declared, Gary Park Shareholder of: Rigel Pharmaceuticals, Employee of: Rigel Pharmaceuticals, Vanessa Taylor Shareholder of: Rigel Pharmaceuticals, Employee of: Rigel Pharmaceuticals, Donna Chow Shareholder of: Rigel, Employee of: Rigel, Meng Lee Shareholder of: Rigel, Employee of: Rigel, Hanzhe Zheng Shareholder of: Rigel, Employee of: Rigel, Andrew Chow Shareholder of: Rigel, Employee of: Rigel

Biocompatible Chemotherapy for Leukemia by Acid-Cleavable, PEGylated FTY720

Targeting the inability of cancerous cells to adapt to metabolic stress is a promising alternative to conventional cancer chemotherapy. FTY720 (Gilenya), an FDA-approved drug for the treatment of multiple sclerosis, has recently been shown to inhibit cancer progression through the down-regulation of essential nutrient transport proteins, selectively starving cancer cells to death. However, the clinical use of FTY720 for cancer therapy is prohibited because of its capability of inducing immunosuppression (lymphopenia) and bradycardia when phosphorylated upon administration. A prodrug to specifically prevent phosphorylation during circulation, hence avoiding bradycardia and lymphopenia, was synthesized by capping its hydroxyl groups with polyethylene glycol (PEG) via an acid-cleavable ketal linkage. Improved aqueous solubility was also accomplished by PEGylation. The prodrug reduces to fully potent FTY720 upon cellular uptake and induces metabolic stress in cancer cells. Enhanced release of FTY720 at a mildly acidic endosomal pH and the ability to substantially down-regulate cell-surface nutrient transporter proteins in leukemia cells only by an acid-cleaved drug were confirmed. Importantly, the prodrug demonstrated nearly identical efficacy to FTY720 in an animal model of BCR-Abl-driven leukemia without inducing bradycardia or lymphopenia in vivo, highlighting its potential clinical value. The prodrug formulation of FTY720 demonstrates the utility of precisely engineering a drug to avoid undesirable effects by tackling specific molecular mechanisms as well as a financially favorable alternative to new drug development. A multitude of existing cancer therapeutics may be explored for prodrug formulation to avoid specific side effects and preserve or enhance therapeutic efficacy.

Topical steroids: A non-surgical approach for recurrent macular holes

PURPOSE

Report a case of a recurrent macular hole which completely resolved with a non-surgical approach with steroid drops.

OBSERVATIONS

While traction is considered the mayor contributor to full thickness macular hole formation, retinal hydration as that in cystoid macular edema also plays an important role.

CONCLUSIONS AND IMPORTANCE

Topical corticosteroid drops can be considered as an alternative therapy for small recurrent macular holes that lack tractional components and have an appearance of cystoid changes on the edges of the hole.

Hybrid 3D/2D Convolutional Neural Network for Hemorrhage Evaluation on Head CT

BACKGROUND AND PURPOSE

Convolutional neural networks are a powerful technology for image recognition. This study evaluates a convolutional neural network optimized for the detection and quantification of intraparenchymal, epidural/subdural, and subarachnoid hemorrhages on noncontrast CT.

MATERIALS AND METHODS

This study was performed in 2 phases. First, a training cohort of all NCCTs acquired at a single institution between January 1, 2017, and July 31, 2017, was used to develop and cross-validate a custom hybrid 3D/2D mask ROI-based convolutional neural network architecture for hemorrhage evaluation. Second, the trained network was applied prospectively to all NCCTs ordered from the emergency department between February 1, 2018, and February 28, 2018, in an automated inference pipeline. Hemorrhage-detection accuracy, area under the curve, sensitivity, specificity, positive predictive value, and negative predictive value were assessed for full and balanced datasets and were further stratified by hemorrhage type and size. Quantification was assessed by the Dice score coefficient and the Pearson correlation.

RESULTS

A 10,159-examination training cohort (512,598 images; 901/8.1% hemorrhages) and an 862-examination test cohort (23,668 images; 82/12% hemorrhages) were used in this study. Accuracy, area under the curve, sensitivity, specificity, positive predictive value, and negative-predictive value for hemorrhage detection were 0.975, 0.983, 0.971, 0.975, 0.793, and 0.997 on training cohort cross-validation and 0.970, 0.981, 0.951, 0.973, 0.829, and 0.993 for the prospective test set. Dice scores for intraparenchymal hemorrhage, epidural/subdural hemorrhage, and SAH were 0.931, 0.863, and 0.772, respectively.

CONCLUSIONS

A customized deep learning tool is accurate in the detection and quantification of hemorrhage on NCCT. Demonstrated high performance on prospective NCCTs ordered from the emergency department suggests the clinical viability of the proposed deep learning tool.

Deep-Learning Convolutional Neural Networks Accurately Classify Genetic Mutations in Gliomas

BACKGROUND AND PURPOSE

The World Health Organization has recently placed new emphasis on the integration of genetic information for gliomas. While tissue sampling remains the criterion standard, noninvasive imaging techniques may provide complimentary insight into clinically relevant genetic mutations. Our aim was to train a convolutional neural network to independently predict underlying molecular genetic mutation status in gliomas with high accuracy and identify the most predictive imaging features for each mutation.

MATERIALS AND METHODS

MR imaging data and molecular information were retrospectively obtained from The Cancer Imaging Archives for 259 patients with either low- or high-grade gliomas. A convolutional neural network was trained to classify isocitrate dehydrogenase 1 (IDH1) mutation status, 1p/19q codeletion, and O6-methylguanine-DNA methyltransferase (MGMT) promotor methylation status. Principal component analysis of the final convolutional neural network layer was used to extract the key imaging features critical for successful classification.

RESULTS

Classification had high accuracy: IDH1 mutation status, 94%; 1p/19q codeletion, 92%; and MGMT promotor methylation status, 83%. Each genetic category was also associated with distinctive imaging features such as definition of tumor margins, T1 and FLAIR suppression, extent of edema, extent of necrosis, and textural features.

CONCLUSIONS

Our results indicate that for The Cancer Imaging Archives dataset, machine-learning approaches allow classification of individual genetic mutations of both low- and high-grade gliomas. We show that relevant MR imaging features acquired from an added dimensionality-reduction technique demonstrate that neural networks are capable of learning key imaging components without prior feature selection or human-directed training.

Differences in Surgical Performance of Internal Limiting Membrane Peeling for Macular Hole Repair Between Supervised Vitreoretinal Fellows and Vitreoretinal Faculty at a Single Institution

Purpose:

To investigate the differences in surgical maneuvers between vitreoretinal fellows and experienced vitreoretinal surgeons (attendings) when performing internal limiting membrane (ILM) peel during macular hole (MH) surgery and repair.

Methods:

Prospective case series. Macular hole surgeries performed by fellows and attendings at St Michael’s Hospital (Toronto, Canada) were recorded during a 12-month period. Evaluation of recordings was masked. Total peel time (TPL) in seconds, total movement attempts initiating and extending ILM flaps, intrasurgical complications, and surgical efficiency (ratio of approaches leading to case progression to total approaches) were quantified.

Results:

A total of 145 surgeries were evaluated; 44 met inclusion and exclusion criteria. Of the 44 cases, 25 were performed by fellows and 19 by attendings. Mean TPL was shorter for attendings (336 vs 506 seconds, P = .0032). Attendings had a lower average total movement attempts (32.2 vs 43.2, P = .045) and average flap initiation attempts (16.1 vs 23.3, P = .042). Surgical efficiency was better for attendings (45% vs 37% of approaches led to case progression, P = .038). There was no significant difference between groups in total flap extension attempts or intrasurgical complications.

Conclusions:

Compared to fellows, attendings peel ILM in MH surgery faster, more efficiently with a lower number of flap initiation attempts and total movements.

Bacterial endophthalmitis: 10-year review of the culture and sensitivity patterns of bacterial isolates

OBJECTIVE

To examine the spectrum and sensitivity patterns of bacterial isolates derived from all culture-positive aqueous and vitreous samples submitted for culture and sensitivity analysis at our institution over a 10-year period.

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 368 culture-positive aqueous and vitreous samples from 265 patients were reviewed.

METHODS

Over a decade extending from January 2000 through December 2009, all culture-positive aqueous and vitreous specimens at our institution were identified. Isolated bacterial pathogens and their in vitro antibiotic sensitivities were analyzed.

RESULTS

Approximately 86.4% of patients had positive cultures for either staphylococci (Staphylococcus aureus and coagulase-negative staphylococci [CNS]) or streptococci. Gram-negative bacteria were isolated in only 9.8% of patients. From 2000 to 2004, 81.2% and 55.9% of CNS isolates were sensitive to ciprofloxacin and cefazolin, respectively, compared with 41.2% and 23.5% of isolates in the last 5 years. Over the study period, ceftazidime retained 100% efficacy against the gram-negative isolates tested. Vancomycin was 99.6% effective against the gram-positive isolates tested.

CONCLUSIONS

The microbiology of pathogens in endophthalmitis is evolving, with an increase in streptococcal isolates and a decrease in CNS. The apparent lack of efficacy of conventionally used antibiotics and the emergence of increasingly resistant strains of bacteria may have significant implications in the management of bacterial endophthalmitis.

5-Alkyl-2-urea-Substituted Pyridines: Identification of Efficacious Glucokinase Activators with Improved Properties

Two 1-(4-aryl-5-alkyl-pyridin-2-yl)-3-methylurea glucokinase activators were identified with robust in vivo efficacy. These two compounds possessed higher solubilities than the previously identified triaryl compounds (i.e., AM-2394). Structure-activity relationship studies are presented along with relevant pharmacokinetic and in vivo data.

C5-Alkyl-2-methylurea-Substituted Pyridines as a New Class of Glucokinase Activators

Glucokinase (GK) activators represent a class of type 2 diabetes therapeutics actively pursued due to the central role that GK plays in regulating glucose homeostasis. Herein we report a novel C5-alkyl-2-methylurea-substituted pyridine series of GK activators derived from our previously reported thiazolylamino pyridine series. Our efforts in optimizing potency, enzyme kinetic properties, and metabolic stability led to the identification of compound 26 (AM-9514). This analogue showed a favorable combination of in vitro potency, enzyme kinetic properties, acceptable pharmacokinetic profiles in preclinical species, and robust efficacy in a rodent PD model.

Discovery of Potent and Simplified Piperidinone-Based Inhibitors of the MDM2-p53 Interaction

Continued optimization of the N-substituent in the piperidinone series provided potent piperidinone-pyridine inhibitors 6, 7, 14, and 15 with improved pharmacokinetic properties in rats. Reducing structure complexity of the N-alkyl substituent led to the discovery of 23, a potent and simplified inhibitor of MDM2. Compound 23 exhibits excellent pharmacokinetic properties and substantial in vivo antitumor activity in the SJSA-1 osteosarcoma xenograft mouse model.

Initial outcomes from federally mandated accreditation site surveys of advanced diagnostic imaging facilities performed by the ACR

PURPOSE

The aim of this study was to evaluate the findings of the first year of validation site surveys performed by the ACR pursuant to new federal accreditation requirements for nonhospital advanced diagnostic imaging (ADI) facilities.

METHODS

In the first year of validation site surveys (November 2012 to November 2013), the ACR surveyed 943 ADI facilities across 21 states. Data were extracted from these site survey reports and analyzed on the basis of the survey outcomes and the frequency and type of deficiencies and recommendations. Follow-up data were obtained from the ACR for facilities deemed noncompliant on the site survey to determine if these facilities adequately took the corrective actions necessary to maintain accreditation.

RESULTS

Of the 943 ADI facilities surveyed, 45% (n = 421) were deemed compliant with the ACR accreditation standards, and 55% (n = 522) had one or more deficiencies. Failure to produce the required personnel documentation and absence of mandatory written policies were the two most common causes of deficiencies. Facilities accredited in more modalities tended to fare better in the site surveys, with the number of accredited modalities at a facility negatively associated with the likelihood of a deficiency (P = .007). Of the facilities with deficiencies, 73% (n = 382) took the necessary corrective actions to maintain accreditation, 27% (n = 140) were in the process of taking corrective actions, and no facility has lost accreditation because of an inability to adequately address the deficiencies. Nonbinding recommendations were made to 37% (n = 346) of facilities, and facilities with deficiencies were statistically more likely to receive recommendations (P < .001).

CONCLUSIONS

Initial site surveys of ADI facilities demonstrated a high proportion of deficient facilities, but no facility has lost accreditation because of an inability to correct these deficiencies. Knowledge of the most common sources of deficiencies and recommendations can assist ACR-accredited ADI facilities in better preparing for validation site surveys, reducing the likelihood of facility noncompliance.

Selective and potent morpholinone inhibitors of the MDM2-p53 protein-protein interaction

We previously reported the discovery of AMG 232, a highly potent and selective piperidinone inhibitor of the MDM2-p53 interaction. Our continued search for potent and diverse analogues led to the discovery of novel morpholinone MDM2 inhibitors. This change to a morpholinone core has a significant impact on both potency and metabolic stability compared to the piperidinone series. Within this morpholinone series, AM-8735 emerged as an inhibitor with remarkable biochemical potency (HTRF IC50 = 0.4 nM) and cellular potency (SJSA-1 EdU IC50 = 25 nM), as well as pharmacokinetic properties. Compound 4 also shows excellent antitumor activity in the SJSA-1 osteosarcoma xenograft model with an ED50 of 41 mg/kg. Lead optimization toward the discovery of this inhibitor as well as key differences between the morpholinone and the piperidinone series will be described herein.

Discovery of AMG 232, a potent, selective, and orally bioavailable MDM2-p53 inhibitor in clinical development

We recently reported the discovery of AM-8553 (1), a potent and selective piperidinone inhibitor of the MDM2-p53 interaction. Continued research investigation of the N-alkyl substituent of this series, focused in particular on a previously underutilized interaction in a shallow cleft on the MDM2 surface, led to the discovery of a one-carbon tethered sulfone which gave rise to substantial improvements in biochemical and cellular potency. Further investigation produced AMG 232 (2), which is currently being evaluated in human clinical trials for the treatment of cancer. Compound 2 is an extremely potent MDM2 inhibitor (SPR KD = 0.045 nM, SJSA-1 EdU IC50 = 9.1 nM), with remarkable pharmacokinetic properties and in vivo antitumor activity in the SJSA-1 osteosarcoma xenograft model (ED50 = 9.1 mg/kg).

Discovery and Optimization of Potent GPR40 Full Agonists Containing Tricyclic Spirocycles

GPR40 (FFAR1 or FFA1) is a target of high interest being pursued to treat type II diabetes due to its unique mechanism leading to little risk of hypoglycemia. We recently reported the discovery of AM-1638 (2), a potent full agonist of GPR40. In this report, we present the discovery of GPR40 full agonists containing conformationally constrained tricyclic spirocycles and their structure-activity relationships leading to more potent agonists such as AM-5262 (26) with improved rat PK profile and general selectivity profile. AM-5262 enhanced glucose stimulated insulin secretion (mouse and human islets) and improved glucose homeostasis in vivo (OGTT in HF/STZ mice) when compared to AM-1638.

Rational design and binding mode duality of MDM2-p53 inhibitors

Structural analysis of both the MDM2-p53 protein-protein interaction and several small molecules bound to MDM2 led to the design and synthesis of tetrasubstituted morpholinone 10, an MDM2 inhibitor with a biochemical IC50 of 1.0 μM. The cocrystal structure of 10 with MDM2 inspired two independent optimization strategies and resulted in the discovery of morpholinones 16 and 27 possessing distinct binding modes. Both analogues were potent MDM2 inhibitors in biochemical and cellular assays, and morpholinone 27 (IC50 = 0.10 μM) also displayed suitable PK profile for in vivo animal experiments. A pharmacodynamic (PD) experiment in mice implanted with human SJSA-1 tumors showed p21(WAF1) mRNA induction (2.7-fold over vehicle) upon oral dosing of 27 at 300 mg/kg.

Fluorescence correlation spectroscopy measurements of the membrane protein TetA in Escherichia coli suggest rapid diffusion at short length scales

Structural inhomogeneities in biomembranes can lead to complex diffusive behavior of membrane proteins that depend on the length or time scales that are probed. This effect is well studied in eukaryotic cells, but has been explored only recently in bacteria. Here we used fluorescence recovery after photobleaching (FRAP) and fluorescence correlation spectroscopy (FCS) to study diffusion of the membrane protein TetA-YFP in E. coli. We find that the diffusion constant determined from FRAP is comparable to other reports of inner membrane protein diffusion constants in E. coli. However, FCS, which probes diffusion on shorter length scales, gives a value that is almost two orders of magnitude higher and is comparable to lipid diffusion constants. These results suggest there is a population of TetA-YFP molecules in the membrane that move rapidly over short length scales (~ 400 nm) but move significantly more slowly over the longer length scales probed by FRAP.

Structure-based design of novel inhibitors of the MDM2-p53 interaction

Structure-based rational design led to the discovery of novel inhibitors of the MDM2-p53 protein-protein interaction. The affinity of these compounds for MDM2 was improved through conformational control of both the piperidinone ring and the appended N-alkyl substituent. Optimization afforded 29 (AM-8553), a potent and selective MDM2 inhibitor with excellent pharmacokinetic properties and in vivo efficacy.

Synthesis and Evaluation of the Metabolites of AMG 221, a Clinical Candidate for the Treatment of Type 2 Diabetes

All eight of the major active metabolites of (S)-2-((1S,2S,4R)-bicyclo[2.2.1]heptan-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-one (AMG 221, compound 1), an inhibitor of 11β-hydroxysteroid dehydrogenase type 1 that has entered the clinic for the treatment of type 2 diabetes, were synthetically prepared and confirmed by comparison with samples generated in liver microsomes. After further profiling, we determined that metabolite 2 was equipotent to 1 on human 11β-HSD1 and had lower in vivo clearance and higher bioavailability in rat and mouse. Compound 2 was advanced into a pharmacodynamic model in mouse where it inhibited adipose 11β-HSD1 activity.

Progression of coronary artery calcium predicts all-cause mortality

OBJECTIVES

This study examined a large cohort to assess whether progression of coronary artery calcium (CAC) was associated with all-cause mortality, and which among 3 different methods to assess CAC progression provided the best estimate of risk.

BACKGROUND

Serial assessment of CAC scores has been proposed as a method to follow progression of coronary artery disease, and it has been suggested that excessive CAC progression may be a useful noninvasive predictor of the patient's risk of future events. However, the optimal method to measure calcium progression has not been well established.

METHODS

The study sample consisted of 4,609 consecutive asymptomatic individuals referred by primary physicians for CAC measurement with electron beam tomography, who underwent repeat screening. Three general statistical approaches were taken: 1) the absolute difference between follow-up and baseline CAC score; 2) percent annualized differences between follow-up and baseline CAC score; and 3) difference between square root of baseline and square root of follow-up CAC score >2.5 (the "SQRT method").

RESULTS

The average interscan time was 3.1 years, and there were 288 deaths. Progression of CAC was significantly associated with mortality regardless of the method used to assess progression (p < 0.0001). After adjusting for baseline score, age, sex, and time between scans, the best CAC progression model to predict mortality was the SQRT method (hazard ratio [HR]: 3.34; 95% confidence interval [CI]: 2.65 to 4.21; p < 0.0001), followed by a >15% yearly increase (HR: 2.98; 95% CI: 2.20 to 4.95; p < 0.0001). Progression was very limited and did not predict mortality in patients with baseline CAC = 0.

CONCLUSIONS

The CAC progression added incremental value in predicting all-cause mortality over baseline score, time between scans, demographics, and cardiovascular risk factors. Serial assessment may have clinical value in assessing plaque progression and future cardiovascular risk.

A genetic approach to stratification of risk for age-related macular degeneration

The genetic determinants of age-related macular degeneration (AMD) are reviewed and a novel approach to risk determination based upon inherited genetic polymorphisms and smoking history is presented. Although AMD was long thought to have primarily an environmental etiology, genetic variation is now known to account for the majority of the disease risk, with variations in the genes of the complement pathways playing a prominent role. Independent and validated clinical studies have implicated the C3 gene and its regulator, complement factor H (1q31.1), complement component 2 (6q21.33), and complement factor B (6q21.33). Subtle variations in complement activity increase the risk of symptomatic macular inflammation with age. A second group of AMD-associated genetic markers may aggravate complement-mediated inflammation by permitting retinal oxidative damage. Variation within the chromosomal site (10q26) coding a mitochondrial-associated protein (age-related maculopathy susceptibility 2) and an independent variation within the mitochondrial genome itself (A4917G) suggest a contributing pathophysiological role of retinal oxidative stress. A genetic panel of disease-susceptibility markers and smoking history can identify a group of individuals with greater than 65% lifetime risk of AMD. The introduction of genetic marker testing into clinical practice may identify patients with early disease who may be aided by presymptomatic monitoring or inclusion into trials of newer prophylactic agents.

IDENTIFICATION OF A NOVEL IN VITRO METABONATE FROM LIVER MICROSOMAL INCUBATIONS

In vitro drug metabolism studies during the early drug discovery stage are becoming increasingly important. With the increasing demand for high throughput and quick turnaround time for in vitro metabolism studies, however, careful examination of the results and proper design of the experiments are still crucial. In this communication, we report the identification and mechanism of formation of a novel metabonate from incubations of a diamine-containing compound with liver microsomes. The metabonate appeared to be the major product, and its formation was NADPH- and microsomal protein-dependent. Liquid chromatography/mass spectrometry and NMR analysis of the metabonate indicated an extra carbon and unusual formation of an imidazolidine ring. Further studies revealed that this metabonate was not a true biotransformation product from the diamine compound itself in the microsomal incubation, but rather a product resulting from a condensation reaction between the compound and a metabolite of the solvent (alcohol) used in the incubation. When the microsomal incubations contained a small amount of methanol or ethanol as solvent, the alcohols were metabolized to formaldehyde or acetaldehyde, which then condensed with the diamine compound through an imine intermediate to form the metabonate. The compound itself was metabolically stable in vitro when acetonitrile or dimethyl sulfoxide was used as solvent. During the study of in vitro microsomal stability and metabolite identification of amine-containing compounds, the use of alcohol as solvent should be avoided.

HIV disease progression and limited antiretroviral treatment options for a HIV-1 infected individual with myoclonic epilepsy associated with ragged red fibers

We describe a 50-year-old Caucasian man with a family history of myoclonic epilepsy associated with ragged red fibers (MERRF) and a diagnosis of Human Immunodeficiency Virus (HIV). The patient had multiple risk factors for contracting HIV and was being followed in our clinic at the time of his diagnosis. Initial testing following seroconversion revealed a baseline CD4+ T-lymphocyte count of 652 x 10(6)cells/l and a HIV-1 RNA of 14,781 copies/ml. He reported exercise intolerance and had mild neurologic deficits, which worsened around the time of HIV seroconversion. These symptoms led to his subsequent diagnosis of MERRF by the detection of the A8344G point mutation in the tRNA(Lys) gene of mitochondrial DNA (mtDNA). The baseline estimated proportion of mutant genome was 39%. He showed a rapid course of HIV disease progression with a CD4+ T-lymphocyte nadir of 174 x 10(6) cells/l associated with a HIV-1 RNA of 238,178 copies/ml, within 17 months following HIV seroconversion. To avoid further mitochondrial insult, which could result from the use of a standard nucleoside reverse transcriptase inhibitor-containing regimen, a protease inhibitor regimen consisting of hard-gel saquinavir (Invirase), and lopinavir/ritonavir (Kaletra) was chosen for this patient. The patient's CD4+ T-lymphocyte count increased to 282 x 10(6)cells/l and his viral load became undetectable 7 months following the initiation of antiretroviral therapy. His neurologic symptoms did not worsen on this antiretroviral regimen. When initiating HIV therapy in individuals with metabolic myopathies related to mitochondrial dysfunction, it may be important to design an antiviral regimen that minimizes mitochondrial damage, yet effectively maintains durable viral suppression.

Provocative cervical discography symptom mapping

BACKGROUND CONTEXT

In a small prospective study assessing 10 symptomatic and 10 asymptomatic subjects, Schellhas et al. compared cervical discography to magnetic resonance imaging. Within that study he reported on the distribution of pain for the C3-C4 to C6-C7 levels. Four years later, Grubb and Ellis reported retrospective data from his 12-year experience using cervical discography from C2-C3 to C7-T1 in 173 patients. To date, no large prospective study defining pain referral patterns for each cervical disc has been performed.

PURPOSE

To conduct a prospective visual and statistical descriptive study of pain provocation of a cohort of subjects undergoing cervical discography.

STUDY DESIGN/SETTING

Prospective multicenter descriptive study.

METHODS

Pain referral maps were generated for each disc level from patients undergoing cervical discography with at least two levels assessed. If concordant pain was reproduced in a morphologically abnormal disc, the subject immediately completed a pain diagram. An independent observer interviewed the subject and recorded the location of provoked symptoms. Visual data were compiled using a body sector bit map, which consisted of 48 clinically relevant body regions. Visual maps with graduated color codes and frequencies of symptom location at each cervical disc level were generated.

RESULTS

A total of 101 symptom provocation maps were recorded during cervical discography on 41 subjects. There were 10 at C2-C3, 19 at C3-C4, 27 at C4-C5, 27 at C5-C6, 16 at C6-C7 and 2 at C7-T1. Predominantly unilateral symptoms were provoked just as often as bilateral symptoms. The C2-C3 disc referred pain to the neck, subocciput and face. The C3-C4 disc referred pain to the neck, subocciput, trapezius, anterior neck, face, shoulder, interscapular and limb. The C4-C5 disc referred pain to the neck, shoulder, interscapular, trapezius, extremity, face, chest and subocciput. The C5-C6 disc referred pain to the neck, trapezius, interscapular, suboccipital, anterior neck, chest and face. The C6-C7 disc referred pain to the neck, interscapular, trapezius, shoulder, extremity and subocciput. At C7-T1 we produced neck and interscapular pain. Visual maps with graduated color codes and frequencies of symptom location at each cervical disc level were generated.

CONCLUSIONS

In conclusion, these results confirm the observations of prior investigators that cervical internal disc disruption can elicit axial and peripheral symptoms. The particular patterns of pain generation allow the discographer to preprocedurally anticipate disc levels to assess. With these data, the number of disc punctures that are required can be limited rather than routinely assessing all cervical discs.

Ferredoxin from sweet pepper (Capsicum annuum L.) intensifying harpin(pss)-mediated hypersensitive response shows an enhanced production of active oxygen species (AOS)

The hypersensitive response (HR) is a form of cell death associated with plant resistance to pathogen infection. Harpin(pss), an elicitor from the bacterium Pseudomonas syringae pv. syringae, induces a HR in non-host plants. Previously, we reported an amphipathic protein from sweet pepper interfering with harpin(pss)-mediated HR. In this report, we isolated and characterized a cDNA clone encoded that amphipathic protein from sweet pepper. This protein is designated as PFLP (plant ferredoxin-like protein) by virtue of its high homology with plant ferredoxin protein containing an N-terminal signal peptide responsible for chloroplast targeting and a putative 2Fe-2S domain responsible for redox activity. Recombinant PFLP obtained from Escherichia coli was able to significantly increase active oxygen species (AOS) generation when mixed with harpin(pss) in tobacco suspension cells. It also showed enhanced HR when co-infiltrated with harpin(pss) in tobacco leaves. We used a transgenic tobacco suspension cells system that constitutively expresses the Pflp gene driven by the CaMV 35S promoter to study the function of PFLP in enhancing harpin(pss)-mediated hypersensitive cell death in vivo. In response to harpin(pss), suspension cells derived from Pflp transgenic tobacco showed a significant increase both in the generation of AOS and in cell death as compared to the wild type. AOS inhibitors diphenylene iodonium chloride (DPI) and lanthanum chlorate (LaCl3) were used to study the involvement of AOS in harpin(pss)-induced cell death. Our results demonstrate enhanced generation of AOS is necessary to cause enhanced hypersensitive cell death in Pflp transgenic tobacco cells and it is plasma membrane-bound NADPH-oxidase-dependent. Sub-cellular localization studies showed that PFLP is present in the cytoplasm and chloroplast of Pflp transgenic tobacco cells, but only in the chloroplast, not in the cytoplasm, of wild-type tobacco cells. It is possible that PFLP can change the redox state of the cell upon harpin(pss) inoculation to increase AOS generation and hypersensitive cell death. Overall, this study will provide a new insight in the functional properties of ferredoxin in hypersensitive cell death.

Painless foot drop: an atypical etiology of a common presentation

Weakness of the dorsiflexor muscles of the foot is a relatively common presentation. In most cases, the etiology involves a peripheral injury to the common peroneal nerve. These patients usually present with lower motor neuron findings on evaluation. In contrast, if upper motor neuron findings were present a central lesion should be suspected and appropriate imaging studies are performed. We describe a patient with painless foot drop and lower motor findings on examination that was diagnosed with multiple sclerosis. This case demonstrates that multiple sclerosis can masquerade as a peripheral process in some patients.

Ultrasound biomicroscopy of sclerotomy sites: the effect of vitreous shaving around sclerotomy sites during pars plana vitrectomy

PURPOSE

To study the difference in the amount of vitreous incarceration between conventional pars plana vitrectomy (PPV) and PPV with vitreous shaving around sclerotomy sites.

METHODS

A dynamic in vivo examination using ultrasound biomicroscopy (UBM) was performed on the sclerotomy sites of 22 eyes after PPV. Patients were divided into two groups. In the study group (n = 11), the vitreous was completely shaved from the internal initial sclerotomy by cotton-tip depressed vitrectomy under coaxial illumination. In the control group (n = 11), no vitreous shaving was performed.

RESULTS

Vitreous incarceration into sclerotomy sites was significantly less in the study group compared with the control group (P <0.001). No difference was seen among the three sclerotomy sites regarding vitreous incarceration within individual eyes. No difference was seen between eyes operated by right- and left-handed surgeons.

CONCLUSIONS

Vitreous shaving of sclerotomy sites using depressed vitrectomy significantly reduces vitreous incarceration. This may reduce the rate of sclerotomy-related complications following PPV in selected cases.

Dentate hilar mossy cells and somatostatin-containing neurons are immunoreactive for the alpha8 integrin subunit: characterization in normal and kainic acid-treated rats

Integrins are heterodimeric cell surface receptors composed of different alpha and beta subunits that mediate cell-cell and cell-extracellular matrix interactions. They have been implicated in the regulation of neuronal migration, differentiation, process outgrowth, and plasticity. The alpha8 integrin subunit associates exclusively with the beta1 subunit to form a receptor (alpha8beta1) for fibronectin, vitronectin, tenascin, and osteopontin. In a previous study, we demonstrated that hippocampal dentate hilar neurons are immunoreactive for alpha8. The present study identifies the major types of alpha8-immunoreactive hilar neurons and characterizes the effects of kainic acid-induced seizures on alpha8-immunoreactivity in these cells. Examination of the hilus in normal rats revealed alpha8-immunoreactivity in the somatodendritic compartments of large hilar neurons identified as mossy cells, including a subset of dendritic thorny excrescences that were contacted by large mossy fiber terminals. alpha8-immunoreactivity also was found in approximately 71% of somatostatin-containing hilar cells. Kainic acid-induced seizures dramatically and rapidly altered the levels and distribution of alpha8-immunoreactivity in hilar neurons. After 1.5 h of seizures, alpha8-immunoreactivity in their dendrites was reduced greatly. One day after kainic acid treatment, labeling was diminished throughout the somatodendritic compartments of most hilar cells. This decrease appeared to be transient, since alpha8 labeling returned to normal levels in surviving hilar neurons within 2 weeks of treatment. In addition, many alpha8-immunoreactive hilar neurons, particularly in caudal dentate regions, were lost 3-5 weeks after kainic acid treatment. Our findings suggest that alpha8beta1 may mediate adhesive interactions of the dendritic processes of mossy cells and somatostatin-containing hilar neurons with other cellular elements or with extracellular matrix components. They also suggest that alpha8 may be susceptible to activity-dependent proteolysis that could modulate its function in the somatodendritic compartment of these cells.