High Phosphate-Binding Capacity of Oxylanthanum Carbonate with a Low Medication Volume: Comparison with Commercially Available Phosphate Binders.

BACKGROUND: A key focus for chronic kidney disease management is phosphate control, but currently available binders have suboptimal phosphate-binding capacity, and their characteristics result in low adherence and poor phosphate regulation. Oxylanthanum carbonate, a novel compound that uses proprietary nanoparticle technology to deliver lanthanum, has the potential to combine high phosphate-binding capacity with good intake convenience, thus improving adherence and patient quality of life. The goal of this study was to assess the volume of oxylanthanum Carbonate required to bind 1 g of phosphate and compare it with other currently available phosphate binders to determine which binder allows for the highest normalized potency with the lowest daily medication volume. METHODS: Six phosphate binders were assessed: ferric citrate, calcium acetate, lanthanum carbonate, sevelamer carbonate, sucroferric oxyhydroxide, and oxylanthanum carbonate. Table volume measurements were taken using fluid displacement in corn oil or water. Mean daily dose volume to bind 1 g of phosphate was calculated as volume per tablet multiplied by the mean number of tablets taken per day. Volume to bind 1 g of phosphate was calculated by dividing the volume per tablet by its in vivo binding capacity. RESULTS: Oxylanthanum carbonate had the lowest mean volume, daily phosphate binder dose volume, and equivalent phosphate-binding dose volume (volume to bind 1 g of phosphate for each binder). CONCLUSIONS: Oxylanthanum carbonate has the lowest daily phosphate binder dose volume and the smallest volume required to bind 1 g of phosphate compared to all other commercially available phosphate binders. A randomized trial that compares gastrointestinal tolerability across binders would be warranted to demonstrate acceptability and adherence in the target population.

Schedule-Dependent Synergy Between the Histone Deacetylase Inhibitor Belinostat and the Dihydrofolate Reductase Inhibitor Pralatrexate in T-and B-cell Lymphoma Cells in vitro.

Pralatrexate (Folotyn; PLX) and belinostat (Beleodaq; BLS) are registered for the treatment of patients with peripheral T-cell lymphoma (PTCL) and are being considered for other lymphomas. In this study we investigated whether BLS had the ability to potentiate the cytotoxicity of PLX. A panel of lymphoma cell lines was used for the combination studies: the B-cell SUDHL-4, SUDHL-5, HT, Jeko-1 and T-cell Karpas-299 and Hut-78. Uptake of PLX was mediated by the reduced folate carrier (RFC). PLX showed a 6-fold better RFC substrate affinity compared to methotrexate, and 2-fold better than levoleucovorin (l-LV). Sensitivity expressed as the concentration that resulted in 50% growth inhibition (IC50) after 72 hr exposure to PLX varied from 2.8 to 20 nM and for BLS from 72 to 233 nM, independent of the background of the cell lines. The interaction between BLS and PLX was studied using the median-drug effect analysis. At a fixed molar ratio between the drugs based on the IC50 concentration the average combination index (CI) for all cell lines showed additivity (CI: around 1.0). In three selected cell lines (SUDHL-4, SUDHL-5, and HT) sequential exposure (24 h pretreatment with BLS, followed by 48 h to PLX + BLS), did not improve interaction (CI: 0.9-1.4). As an alternative approach a non-fixed ratio was used by exposing SUDHL-4, SUDHL-5, and HT cells to IC25 concentrations of either BLS or PLX in combination with the other drug. Exposure to IC25 of PLX did not decrease the IC50 for BLS (CI from 0.6-1.2), but exposure to IC25 of BLS markedly increased PLX sensitivity (low CIs from 0.40 to 0.66). Mechanistic studies focused on induction of apoptosis, and showed cleavage of predominantly caspase-9 in HT and SUDHL-4 cells for both drugs at their IC50s, being similar in the combination setting. Moreover, at these concentrations, the drugs were shown to confer an S-phase arrest. In conclusion, the combination of PLX and BLS showed additivity in various lymphoma cell lines, with a schedule-dependent synergism in B-cell lymphoma. Based on these data, proficient inhibition of HDAC activity by BLS holds promise in sensitization of tumor cells to PLX.

Inactivation of apaziquone by haematuria: implications for the design of phase III clinical trials against non-muscle invasive bladder cancer.

PURPOSE: Despite positive responses in phase II clinical trials, the bioreductive prodrug apaziquone failed to achieve statistically significant activity in non-muscle invasive bladder cancer in phase III trials. Apaziquone was administered shortly after transurethral resection and here we test the hypothesis that haematuria inactivates apaziquone. METHODS: HPLC analysis was used to determine the ability of human whole blood to metabolise apaziquone ex vivo. An in vitro model of haematuria was developed and the response of RT112 and EJ138 cells following a 1-h exposure to apaziquone was determined in the presence of urine plus or minus whole blood or lysed whole blood. RESULTS: HPLC analysis demonstrated that apaziquone is metabolised by human whole blood with a half-life of 78.6 ± 23.0 min. As a model for haematuria, incubation of cells in media containing up to 75% buffered (pH 7.4) urine and 25% whole blood was not toxic to cells for a 1-h exposure period. Whole blood (5% v/v) significantly (p < 0.01) reduced the potency of apaziquone in this experimental model. Lysed whole blood also significantly (p < 0.05) reduced cell growth, although higher concentrations were required to achieve an effect (15% v/v). CONCLUSIONS: The results of this study demonstrate that haematuria can reduce the potency of apaziquone in this experimental model. These findings impact upon the design of further phase III clinical trials and strongly suggest that apaziquone should not be administered immediately after transurethral resection of non-muscle invasive bladder cancer when haematuria is common.

Acquired Localized Cutis Laxa: A Case Report and the Role of Plastic Surgery.

Cutis laxa is an uncommon connective tissue disorder affecting the elastin fibers leading to lax and pendulous skin and in generalized form can present with systemic involvement. Congenital cutis laxa is common in comparison to acquired cutis laxa and has varied inheritance patterns. Treatment is chiefly observation in congenital cutis laxa, and there is a paucity of literature on surgical management in acquired cutis laxa. We report a rare case of acquired localized cutis laxa with a review of literature on the role of plastic surgery in this condition.

Double-Blind, Randomized, Placebo-controlled Studies Evaluating Apaziquone (E09, Qapzola™) Intravesical Instillation Post Transurethral Resection of Bladder Tumors for the Treatment of Low-risk Non-Muscle Invasive Bladder Cancer.

BACKGROUND: Guidelines recommend a single postoperative instillation of intravesical chemotherapy within 24 hours of transurethral resection of bladder tumors (TURBT) in patients with low- and intermediate-risk non-muscle invasive bladder cancer (NMIBC) to reduce recurrence risk. OBJECTIVE: To evaluate the 2-year recurrence rate (2-YRR) of bladder cancer in randomized patients with Ta, G1-G2 histology who receive TURBT plus apaziquone versus TURBT plus placebo. METHODS: Two nearly identical Phase 3, multinational, randomized, double-blind, placebo-controlled trials were conducted in patients with histologically confirmed Ta, G1-G2 NMIBC (Target Population) to evaluate the efficacy/safety of a single instillation of apaziquone post-TURBT. A single intravesical instillation of apaziquone (4 mg/40 mL) or placebo was administered within 6 hours post-TURBT. The primary and secondary efficacy endpoints were 2-YRR and time to recurrence (TTR) respectively. RESULTS: Overall, 1614 patients were enrolled, including 1146 patients in the Target Population. Individually, the two studies did not meet statistical significance for 2-YRR (38.0% vs 44.6% ; 39.7% vs. 46.3%). Because apaziquone is rapidly metabolized in blood, a post hoc subgroup analysis was performed by time window of drug instillation post-TURBT. Patients who had drug instilled in the time window 60±30 minutes post-TURBT demonstrated 20.3% and 20.8% reduction in 2-YRR and 56% (HR = 0.44) and 45% (HR = 0.55) reduction in hazards for TTR in two studies respectively. Apaziquone was well tolerated with minimal toxicity. CONCLUSIONS: Two identical Phase 3 studies supported the safety of apaziquone (4 mg/40 mL) administered as a single intravesical instillation post-TURBT and identified efficacy when instilled within 60±30-minutes time interval which requires further study.

'Sausage finger' with 'Rice bodies'.

Although both pulmonary and extrapulmonary tuberculosis (TB) are commonly encountered in developing countries, tenosynovitis is an uncommon presentation of musculoskeletal TB. TB mimics a lot of other conditions and causes diagnostic dilemma in day-to-day practice. We present the case of a 30-year-old male who presented with the complaints of swelling of right index finger which was initially suspected to be giant cell tumour of the flexor tendon sheath but on histological examination turned out to be tuberculous tenosynovitis.

An open-label, dose-ranging study of Rolontis, a novel long-acting myeloid growth factor, in breast cancer.

This randomized, open-label, active-controlled study investigated the safety and efficacy of three doses of Rolontis (eflapegrastim), a novel, long-acting myeloid growth factor, versus pegfilgrastim in breast cancer patients being treated with docetaxel and cyclophosphamide (TC). The primary efficacy endpoint was duration of severe neutropenia (DSN) during the first cycle of treatment. Patients who were candidates for adjuvant/neoadjuvant TC chemotherapy were eligible for participation. TC was administered on Day 1, followed by 45, 135, or 270 µg/kg Rolontis or 6 mg pegfilgrastim on Day 2. Complete blood counts were monitored daily when the absolute neutrophil count (ANC) fell to <1.5 × 109 /L. Up to four cycles of TC were investigated. The difference in DSN (time from ANC <0.5 × 109 /L to ANC recovery ≥2.0 × 109 /L) between the Rolontis and pegfilgrastim groups was -0.28 days (confidence interval [CI]: -0.56, -0.06) at 270 µg/kg, 0.14 days (CI: -0.28, 0.64) at 135 µg/kg, and 0.72 days (CI: 0.19, 1.27) at 45 µg/kg. Noninferiority to pegfilgrastim was demonstrated at 135 µg/kg (P = 0.002) and 270 µg/kg (P < .001), with superiority demonstrated at 270 µg/kg (0.03 days; P = 0.023). The most common treatment-related adverse events (AEs) were bone pain, myalgia, arthralgia, back pain, and elevated white blood cell counts, with similar incidences across groups. All doses of Rolontis were well tolerated, and no new or significant treatment-related toxicities were observed. In Cycle 1, Rolontis demonstrated noninferiority at the 135 µg/kg dose and statistical superiority in DSN at the 270 µg/kg dose when compared to pegfilgrastim.

A phase I study to determine the pharmacokinetics and urinary excretion of belinostat and metabolites in patients with advanced solid tumors.

PURPOSE: Belinostat is an inhibitor of histone deacetylase enzymes, resulting in DNA repair inhibition and apoptosis. Present data are lacking to provide dosing recommendations in renal insufficiency. The purpose of this trial was to assess the pharmacokinetics (PK) of belinostat and belinostat metabolites in plasma and urine. METHODS: This was a phase I, single-center, open-label, two-part study. In Part I, patients received single-agent belinostat 1000 mg/m2. Blood and urine samples were collected at pre-specified time points to determine PK of belinostat and metabolites and their elimination in urine. In Part II, patients were permitted to continue belinostat in 21-day cycles on Days 1 through 5 until disease progression, unacceptable toxicity, or according to patient preference. RESULTS: A total of nine patients with advanced solid tumors were treated. Median t max for belinostat was observed 10 min after the start of infusion. Concentrations of belinostat rapidly declined with a t 1/2 of 2.9 h. The mean fraction of belinostat excreted unchanged in urine was 0.926 %. The metabolites belinostat glucuronide and 3-ASBA represented the largest fractions of belinostat dose excreted in urine (30.5 and 4.61 %, respectively), while renal excretion appeared to be a minor route of elimination for the parent belinostat (<1 %). The most common adverse events were nausea, fatigue, and diarrhea. One Grade 3 adverse event (constipation) was thought to be treatment related. CONCLUSIONS: Urinary elimination of parent belinostat was minimal, although a combined 36.7 % of belinostat metabolites were excreted in urine. Since these metabolites are primarily inactive, belinostat may not require dosage adjustment in renal dysfunction.

Phase 1 study evaluating the safety and pharmacokinetics of pralatrexate in relapsed/refractory advanced solid tumors and lymphoma patients with mild, moderate, and severe renal impairment.

PURPOSE: Pralatrexate is a folate analogue indicated for the treatment of relapsed or refractory peripheral T-cell lymphoma. It has not been formally tested in patients with renal impairment. This study evaluated the pharmacokinetic (PK) profile of pralatrexate in patients with renal impairment and with relapsed/refractory advanced solid tumors and lymphoma. METHODS: This was an open-label, nonrandomized, phase 1 study. Eligible patients received pralatrexate administered as an IV push over 3-5 min once weekly for 6 weeks in 7-week cycles until progressive disease or intolerable toxicity. Four cohorts of 6 patients were planned for a total of 24 patients. Patients with normal renal function (Cohort A), mild (Cohort B), and moderate renal impairment (Cohort C) received 30 mg/m2 pralatrexate once weekly for 6 weeks in 7-week cycles, and patients with severe renal impairment (Cohort D) were to be administered 20 mg/m2 once weekly for 6 weeks. Plasma and urine samples were collected at pre-specified time points to determine the PK profile of pralatrexate in each treatment cohort. Patients were followed for safety and tolerability. RESULTS: A total of 29 patients were enrolled and 27 patients (14 male) received at least 1 dose of pralatrexate. Because of a qualifying toxicity in Cohort C, the starting dose for Cohort D was reduced to 15 mg/m2. Chronic renal impairment led to a decrease in renal clearance of the pralatrexate diastereomers, PDX-10a and PDX-10b, but systemic exposure to these diastereomers was not dramatically affected by renal impairment. Pralatrexate exposure in Cohort D (15 mg/m2) was similar to the exposure in other cohorts (30 mg/m2). No apparent difference in toxicity between the four treatment cohorts was observed, except for an increase in cytopenias in patients with severe renal impairment. CONCLUSION: Pralatrexate exposure, at a dose of 30 mg/m2, in patients with mild or moderate renal impairment was similar to the exposure in patients with normal renal function. For patients with severe renal impairment only, a pralatrexate dose of 15 mg/m2 is recommended.

A phase I clinical trial of the effect of belinostat on the pharmacokinetics and pharmacodynamics of warfarin.

PURPOSE: Belinostat is a potent small molecule inhibitor that exerts its antitumor effect through inhibition of histone deacetylase. The purpose of this study was to evaluate the pharmacokinetics and pharmacodynamics of warfarin (as a reference drug metabolized by CYP2C9) in the presence and absence of belinostat. METHODS: We conducted a phase I, single-center, open-label, drug-drug interaction study between belinostat and warfarin. In part I, patients were given warfarin 5 mg orally (day-14 and 3) and belinostat 1000 mg/m(2) (days 1 through 5). Patients receiving benefit continued belinostat on days 1 through 5 every 21 days until disease progression, unacceptable toxicity, or per patient preference. RESULTS: A total of 18 patients were treated. With belinostat, the least-squared means for maximum concentration (C max), area under the curve0-∞, and area under the curve0-t of R-warfarin were slightly increased. However, for the more potent S-warfarin isomer, the same parameters were primarily contained within the pre-specified equivalence limits of 0.80 and 1.25, indicating there was no statistically significant interaction between S-warfarin and belinostat. The most common adverse events were nausea, vomiting, and fatigue. Three grade 3 adverse events (diarrhea 5.6 %, nausea 5.6 %, and vomiting 5.6 %) were thought to be treatment related. Progression-free survival ranged from 0.2 to 13.8 months in all patients. CONCLUSIONS: Belinostat did not significantly affect the pharmacokinetics and pharmacodynamics of warfarin, indicating no clinically relevant effect on the enzymatic activity of CYP2C9.

Pharmacokinetics, metabolism, and excretion of (14)C-labeled belinostat in patients with recurrent or progressive malignancies.

BACKGROUND: Belinostat, a potent pan-inhibitor of histone deacetylase (HDAC) enzymes, is approved in the United States (US) for relapsed/refractory peripheral T-cell lymphoma. In nonclinical studies, bile and feces were identified as the predominant elimination routes (50-70%), with renal excretion accounting for ~30-50%. A Phase 1 human mass balance study was conducted to identify species-dependent variations in belinostat metabolism and elimination. METHODS: Patients received a single 30-min intravenous (i.v.) infusion of (14)C-labeled belinostat (1500 mg). Venous blood samples and pooled urine and fecal samples were evaluated using liquid chromatography-tandem mass spectroscopy for belinostat and metabolite concentrations pre-infusion through 7 days post-infusion. Total radioactivity was determined using liquid scintillation counting. Continued treatment with nonradiolabled belinostat (1000 mg/m(2) on Days 1-5 every 21 days) was permitted. RESULTS: Belinostat was extensively metabolized and mostly cleared from plasma within 8 h (N = 6), indicating that metabolism is the primary route of elimination. Systemic exposure for the 5 major metabolites was >20% of parent, with belinostat glucuronide the predominant metabolite. Mean recovery of radioactive belinostat was 94.5% ± 4.0%, with the majority excreted within 48 and 96 h in urine and feces, respectively. Renal elimination was the principal excretion route (mean 84.8% ± 9.8% of total dose); fecal excretion accounted for 9.7% ± 6.5%. Belinostat was well tolerated, with mostly mild to moderate adverse events and no treatment-related severe/serious events. CONCLUSION: Mass balance was achieved (~95% mean recovery), with metabolism identified as the primary route of elimination. Radioactivity was predominantly excreted renally as belinostat metabolites.

Unexplained perioperative vertebrobasilar stroke in a patient undergoing anterior cervical decompression and disc arthroplasty.

BACKGROUND: Vertebrobasilar stroke associated with the anterior approach to the cervical spine is rare and has not been reported in cervical disc arthroplasty surgery. We report the case of a 60-year-old patient who underwent cervical disc arthroplasty at C4-5, C5-6 and C6-7. Postoperatively, due to symptoms and signs of a cerebellar stroke, magnetic resonance imaging of the brain was obtained confirming this diagnosis. Despite thorough investigation no specific identifiable cause for the stroke has been identified. We hypothesis an unrecognised period of intraoperative hypotension may have caused a temporary reduction in vertebrobasilar blood flow. METHODS: A retrospective review of the patient's case notes and a focused review of literature has been performed. RESULTS: Now two years postoperatively the patient has regained full power but has residual problems with balance. She has neuralgic pain down the right side of her body which following investigation is believed to result from the stroke. CONCLUSIONS / LEVEL OF EVIDENCE: Surgeons should be aware vertebrobasilar stroke is a possible rare perioperative complication associated with anterior cervical decompression and disc arthroplasty. Level V.

The orthotopic Fischer/AY-27 rat bladder urothelial cell carcinoma model to test the efficacy of different apaziquone formulations.

OBJECTIVES: Apaziquone used intravesically showed significant activity in phase I and II marker lesion studies in non-muscle-invasive bladder cancer. The objective of this study was to assess antitumor activity and safety of 3 different formulations of intravesical apaziquone in an orthotopic rat bladder cancer model. MATERIALS AND METHODS: Female Fischer F344 rats were instilled with 1.5 × 10(6) AY-27 urothelial cell carcinoma cells and divided in 3 treatment groups (n = 10) and 1 placebo group (n = 6). Intravesical treatment was administered for 1 hour on days 2 and 5. Rats were treated with apaziquone in the formulation used in phase I/II clinical trials (group 1); apaziquone with an altered buffering capacity being used in phase III clinical trials (group 2), and apaziquone as in group 2, but without propylene glycol in the diluent (group 3). On days 5 and 14, the bladder wall was inspected by cystoscopy and evaluated for macroscopic tumor growth. After sacrificing the rats (day 14), cystectomy was performed and the bladders were investigated. RESULTS: There were no signs of any toxicity due to the study drug. On histopathologic examination of the bladders 0, 1, and 2 tumors per group were found in group 1, 2, and 3, respectively. In the placebo-treated group, 60% of animals developed tumor, which is comparable to untreated animals. CONCLUSIONS: Apaziquone showed an excellent antitumor activity. The effectiveness of apaziquone in this orthotopic rat bladder tumor model corroborates the clinical observations and implies the validity of this model.

Lucanthone is a novel inhibitor of autophagy that induces cathepsin D-mediated apoptosis.

Cellular stress induced by nutrient deprivation, hypoxia, and exposure to many chemotherapeutic agents activates an evolutionarily conserved cell survival pathway termed autophagy. This pathway enables cancer cells to undergo self-digestion to generate ATP and other essential biosynthetic molecules to temporarily avoid cell death. Therefore, disruption of autophagy may sensitize cancer cells to cell death and augment chemotherapy-induced apoptosis. Chloroquine and its analog hydroxychloroquine are the only clinically relevant autophagy inhibitors. Because both of these agents induce ocular toxicity, novel inhibitors of autophagy with a better therapeutic index are needed. Here we demonstrate that the small molecule lucanthone inhibits autophagy, induces lysosomal membrane permeabilization, and possesses significantly more potent activity in breast cancer models compared with chloroquine. Exposure to lucanthone resulted in processing and recruitment of microtubule-associated protein 1 light chain 3 (LC3) to autophagosomes, but impaired autophagic degradation as revealed by transmission electron microscopy and the accumulation of p62/SQSTM1. Microarray analysis, qRT-PCR, and immunoblotting determined that lucanthone stimulated a large induction in cathepsin D, which correlated with cell death. Accordingly, knockdown of cathepsin D reduced lucanthone-mediated apoptosis. Subsequent studies using p53(+/+) and p53(-/-) HCT116 cells established that lucanthone induced cathepsin D expression and reduced cancer cell viability independently of p53 status. In addition, lucanthone enhanced the anticancer activity of the histone deacetylase inhibitor vorinostat. Collectively, our results demonstrate that lucanthone is a novel autophagic inhibitor that induces apoptosis via cathepsin D accumulation and enhances vorinostat-mediated cell death in breast cancer models.

Lumbar total disc arthroplasty: coronal midline definition and optimal TDA placement.

It is a general principle with arthroplasty insertion that precise implant centering is critical for long term function and outcome. Whilst some authors have proclaimed that lumbar total disc arthroplasty (TDA) may be different, and that off -centre placement may be functionally well tolerated, these claims are premature: significantly worse clinical results have already been reported with poorly placed TDA at 2 years. Accurate TDA placement requires a precise and consistent definition of the desired coronal midline target (which is currently lacking), as well as a procedural mechanism to optimize placement at that target. We summarize our experience, as well as others', in achieving these two requirements. Long-term outcomes after lumbar TDA insertion should only be compared with results from fusion where TDAs have been implanted accurately.

Significantly improved lumbar arthroplasty placement using image guidance: technical note.

STUDY DESIGN: Technical report. OBJECTIVE: To compare the accuracy of lumbar total disc arthroplasty placement using an image-guidance system (IGS) with conventional fluoroscopy. SUMMARY OF BACKGROUND DATA: Most disc arthroplasties are inserted and analyzed using fluoroscopy. One previous cadaveric study demonstrated beneficial, but insignificant, effects of IGS on total disc arthroplasty placement compared with conventional fluoroscopy. METHODS: Patients were considered for lumbar total disc arthroplasty who had chronic discogenic low back pain unresponsive to nonoperative management for at least 6 months. Total disc arthroplasty was performed in n = 6 with IGS and in n = 14 without IGS. Implant placement was analyzed after surgery using computer software on high-resolution CT with respect to 3 parameters: 1) off-center mal-placement, 2) axial rotational mal-placement, and 3) coronal tilt. RESULTS: Arthroplasties inserted with IGS were positioned with significantly greater accuracy than non-IGS arthroplasties with respect to all 3 parameters measured (off-center: 1.1 +/- 0.3 vs. 2.3 +/- 0.3 mm, P = 0.031; rotation: 88.8 degrees +/- 0.2 degrees vs. 87.1 degrees +/- 0.4 degrees; P = 0.0084; and tilt: 1.0 degrees +/- 0.5 degrees vs. 2.6 degrees +/- 0.3 degrees, P = 0.01). There was no significant difference in operating time between non-IGS controls (123 +/- 5 minutes) and IGS (139 +/- 10 minutes) groups (P = 0.129). CONCLUSION: This is the first clinical study to demonstrate significantly improved accuracy of lumbar total disc arthroplasty placement on CT using IGS compared with conventional fluoroscopy. IGS should be considered for routine use with lumbar total disc arthroplasty insertion.

From proteomics to biomarker discovery in Alzheimer's disease.

Alzheimer's disease (AD) is the most common form of dementia in the elderly. AD is an invariably fatal neurodegenerative disorder with no effective treatment or definitive antemortem diagnostic test. Little is known about the changes in the brain preceding or accompanying initiation of the disease. Understanding the biological processes, which occur during AD onset and/or progression, will improve the diagnosis and treatment of the disease. As we will discuss in this review article, using high-throughput cDNA microarray we identified candidate genes whose expression is altered in the brain of cases at risk for AD dementia. However, it is possible that the use of the cDNA microarray technology alone may underestimate post-transcriptional modifications and therefore provides only a partial view of the biological problem of interest. As such, the combination of cDNA and protein arrays may provide a more global picture of the biological processes being studied. Based on this hypothesis, we initiated a series of high-throughput proteomic studies and found that the expressions of proteins involved in synaptic plasticity are selectively altered in the brain of cases at high risk to develop AD dementia (mild cognitive impairment; MCI). This is consistent with our cDNA microarray evidence showing that the expression of a-type synapsins is selectively altered in the brain of MCI cases. Collectively, these studies support the feasibility and usefulness of high-throughput cDNA microarray and proteomics techniques to study the sequential changes of distinctive gene expression patterns in the brain as a function of the progression of AD dementia.

SELDI ProteinChip(R) Array Technology: Protein-Based Predictive Medicine and Drug Discovery Applications.

Predictive medicine, utilizing the ProteinChip(R) Array technology, will develop through the implementation of novel biomarkers and multimarker patterns for detecting disease, determining patient prognosis, monitoring drug effects such as efficacy or toxicity, and for defining treatment options. These biomarkers may also serve as novel protein drug candidates or protein drug targets. In addition, the technology can be used for discovering small molecule drugs or for defining their mode of action utilizing protein-based assays. In this review, we describe the following applications of the ProteinChip Array technology: (1) discovery and identification of novel inhibitors of HIV-1 replication, (2) serum and tissue proteome analysis for the discovery and development of novel multimarker clinical assays for prostate, breast, ovarian, and other cancers, and (3) biomarker and drug discovery applications for neurological disorders.

Inhibition of base excision repair potentiates iododeoxyuridine-induced cytotoxicity and radiosensitization.

5-Iodo-2'-deoxyuridine (IdUrd) is a halogenated thymidine analogue recognized as an effective in vitro and in vivo radiosensitizer in human cancers. IdUrd-related cytotoxicity and/or radiosensitization are correlated with the extent of IdUrd-DNA incorporation replacing thymidine. IdUrd cytotoxicity and radiosensitization result, in part, from induction of DNA single-strand breaks (SSB) with subsequent enhanced DNA double-strand breaks leading to cell death. Because base excision repair (BER) is a major DNA repair pathway for SSB induced by chemical agents and ionizing radiation, we initially assessed the role of BER in modulating IdUrd cytotoxicity and radiosensitization using genetically matched Chinese hamster ovary cells, with (AA8 cells) and without (EM9 cells) XRCC1 expression. XRCC1 plays a central role in processing and repairing SSBs and double-strand breaks. We found that EM9 cells were significantly more sensitive than parental AA8 cells to IdUrd alone and to IdUrd + ionizing radiation. The EM9 cells also demonstrate increased DNA damage after IdUrd treatment as evaluated by pulse field gel electrophoresis and single cell gel electrophoresis (Comet Assay). BER-competent EM9 cells, which were stably transfected with a cosmid vector carrying the human XRCC1 gene, showed responses to IdUrd similar to AA8 cells. We also assessed the role of methoxyamine, a small molecule inhibitor of BER, in the response of human colon cancer cells (HCT116) to IdUrd cytotoxicity and radiosensitization. Methoxyamine not only was able to increase IdUrd cytotoxicity but also increased the incorporation of IdUrd into DNA of HCT116 human colon cancer cells leading to greater radiosensitization. Thus, a genetic or biochemical impairment of BER results in increased IdUrd-induced cytotoxicity and radiosensitization in mammalian cells.