Isolation and Characterization of a ssDNA Aptamer against Major Soluble Antigen of Renibacterium salmoninarum.

Bacterial kidney disease (BKD) is a major health problem of salmonids, affecting both wild and cultured salmon. The disease is caused by Renibacterium salmoninarum (Rs), a fastidious, slow-growing and strongly Gram-positive diplobacillus that produces chronic, systemic infection characterized by granulomatous lesions in the kidney and other organs, often resulting in death. Fast detection of the pathogen is important to limit the spread of the disease, particularly in hatcheries or aquaculture facilities. Aptamers are increasingly replacing conventional antibodies as platforms for the development of rapid diagnostic tools. In this work, we describe the first instance of isolating and characterizing a ssDNA aptamer that binds with high affinity to p57 or major soluble antigen (MSA), the principal antigen found on the cell wall surface of Rs. Specifically, in this study a construct of the full-length protein containing a DNA binding domain (MSA-R2c) was utilized as target. Aptamers were isolated from a pool of random sequences using GO-SELEX (graphene oxide-systematic evolution of ligands by exponential enrichment) protocol. The selection generated multiple aptamers with conserved motifs in the random region. One aptamer with high frequency of occurrence in different clones was characterized and found to display a strong binding affinity to MSA-R2c with a Kd of 3.0 ± 0.6 nM. The aptamer could be potentially utilized for the future development of a sensor for rapid and onsite detection of Rs in water or in infected salmonids, replacing time-consuming and costly lab analyses.

Current clinical applications of antimullerian hormone.

PURPOSE OF REVIEW: Determine if literature supports the use of anti-Müllerian hormone (AMH) as a useful biomarker of reproductive potential when cumulative live birth rates (CLBRs) per retrieval are used as the outcome variable. RECENT FINDINGS: Advances in technology used in in-vitro fertilization (IVF) permit the use of single embryo transfer to achieve expected pregnancy success rates. Many IVF cycles result in the creation of more than a single embryo suitable for transfer per oocyte retrieval. Cryopreservation permits subsequent use of other embryos with no loss in total reproductive potential from single retrievals. Therefore, an emerging concept in IVF is the CLBR per retrieval as an indicator of the patient's reproductive potential. Using the total reproductive potential from a single retrieval may help patients decide on IVF. As such, any predictor of success that relies upon the live birth rate for a single transfer, as opposed to CLBR per retrieval, is inadequate to estimate the true reproductive potential for patient. AMH has been proposed as a biomarker for reproductive potential, but most studies have correlated an AMH value to a single embryo transfer. SUMMARY: A more appropriate way to use AMH levels may be to correlate the AMH with CLBR per retrieval. AMH may thus prove to be a useful biomarker when counseling patients about what to expect from their treatment.

Phase II randomized trial of carboplatin and gemcitabine with or without dexamethasone pre-treatment in patients with Stage IV non-small cell lung cancer.

PURPOSE: Pre-clinical and early-phase clinical studies have demonstrated that dexamethasone (DEX) administration prior to chemotherapy reduces toxicity and enhances efficacy in the treatment of cancer. We undertook a randomized, phase II multi-institutional trial to evaluate these effects in patients with Stage IV non-small cell lung cancer. METHODS: Patients were treated with carboplatin on day 1 and gemcitabine on days 1 and 8 every 21 days, for up to 6 cycles. Patients were randomized not to receive (Arm 1, n = 25) or to receive (Arm 2, n = 31) DEX orally for 4 days prior to chemotherapy on days 1 and 8. The primary endpoint was the incidence/course of grade 3 and 4 hematologic toxicity. Secondary endpoints included efficacy [response and overall survival (OS)] and evaluation of the Glasgow Prognostic Score (GPS), based on C-reactive protein and albumin levels, to predict survival and toxicity. RESULTS: The incidence/course of grade 3 and 4 hematologic toxicity was significantly reduced in Arm 2 (DEX) versus Arm 1 (no DEX): neutrophils = 13 versus 40 % (p = 0.009) and platelets = 23 versus 44 % (p = 0.03). Response rates and OS were higher in Arm 2 versus Arm 1: 8/31 versus 2/25 (partial response, p = ns) and 378 versus 291 days (p = ns). The GPS significantly predicted survival OS (p = 0.04) but not toxicity. CONCLUSIONS: Pre-treating patients with DEX is a safe, effective, and economic method of reducing the hematologic toxicity of carboplatin and gemcitabine. Our data suggest efficacy may also be enhanced by DEX pre-treatment.

Stereotactic body radiation therapy can be used safely to boost residual disease in locally advanced non-small cell lung cancer: a prospective study.

PURPOSE: To report the results of a prospective, single-institution study evaluating the feasibility of conventional chemoradiation (CRT) followed by stereotactic body radiation therapy (SBRT) as a means of dose escalation for patients with stage II-III non-small cell lung cancer (NSCLC) with residual disease. METHODS AND MATERIALS: Patients without metastatic disease and with radiologic evidence of limited residual disease (≤5 cm) within the site of the primary tumor and good or complete nodal responses after standard CRT to a target dose of 60 Gy were considered eligible. The SBRT boost was done to achieve a total combined dose biological equivalent dose >100 Gy to the residual primary tumor, consisting of 10 Gy × 2 fractions (20 Gy total) for peripheral tumors, and 6.5 Gy × 3 fractions (19.5 Gy total) for medial tumors using the Radiation Therapy Oncology Group protocol 0813 definitions. The primary endpoint was the development of grade ≥3 radiation pneumonitis (RP). RESULTS: After a median follow-up of 13 months, 4 patients developed acute grade 3 RP, and 1 (2.9%) developed late and persistent grade 3 RP. No patients developed grade 4 or 5 RP. Mean lung dose, V2.5, V5, V10, and V20 values were calculated for the SBRT boost, and none were found to significantly predict for RP. Only advancing age (P=.0147), previous smoking status (P=.0505), and high CRT mean lung dose (P=.0295) were significantly associated with RP development. At the time of analysis, the actuarial local control rate at the primary tumor site was 82.9%, with only 6 patients demonstrating recurrence. CONCLUSIONS: Linear accelerator-based SBRT for dose escalation of limited residual NSCLC after definitive CRT was feasible and did not increase the risk for toxicity above that for standard radiation therapy.

A search to identify genetic risk factors for endometriosis.

PROBLEM: To search for molecular markers of endometriosis the following polymorphisms: p53 codon 72 Pro (apoptosis), TNF alpha-308 (inflammation), VEGF-1164AA (angiogenesis), and SOD2 (oxidative stress) were investigated. METHOD OF STUDY: Forty-two women-24 with surgically proven endometriosis and 18 with no endometriosis found at the time of laparoscopy-had buccal swabs taken for DNA analyses of 4 gene polymorphisms including p53codon72, TNF-308 G/A, VEGF-1154G/A, SOD Ala16Val DNA. The frequencies of genotypes and alleles of these polymorphisms were compared between women with and without endometriosis. RESULTS: No specific gene mutation differences for the four genes tested nor differences in the frequencies of heterozygous and homozygous mutations were found between patients with endometriosis and controls. In addition, no differences in allelic frequencies of the four genetic polymorphisms were observed between patients with endometriosis and control. CONCLUSION: Endometriosis is not associated with gene mutations for p53codon72, TNF-308 G/A, VEGF-1154G/A, SOD Ala16Val.

Risk for fatal pulmonary hemorrhage does not appear to be increased following dose escalation using stereotactic body radiotherapy (SBRT) in locally advanced non-small cell lung cancer (NSCLC).

PURPOSE: A prospective single institution study evaluating the feasibility of conventional chemoradiation (CRT) followed by SBRT as a means of dose escalation for patients with stage II-III NSCLC with residual disease recently completed accrual. Two patients enrolled developed unexpected fatal pulmonary hemorrhages. A post-hoc analysis was performed to evaluate for an association between protocol therapy and this grade 5 toxicity. METHODS AND MATERIALS: 17 patients enrolled on the protocol with medial tumors according to the RTOG 0813 definitions, were selected for analysis. Protocol therapy consisted of SBRT boost consisting of 10Gy times two or 6.5Gy times three fractions, after completing initial CRT. Chi-square and ANOVA associations were performed using patient-specific and dosimetric characteristics, particularly volume and point doses to mediastinal structures. RESULTS: After a median follow-up of 13 months, 2 patients developed a grade V pulmonary hemorrhage, in the setting of recurrent disease. Cumulative biological effective doses (BED3) were calculated using an α/ß 3.0 for the pulmonary vasculature and bronchial wall. No volumetric or point doses administered seemed to correlate with the risk for pulmonary hemorrhage, despite an average maximum pulmonary artery dose of 175 Gy BED3. The only significant association with fatal hemorrhage was local recurrence (p = 0.0441). CONCLUSION: SBRT boost does not appear to increase the risk for fatal pulmonary hemorrhage. A cumulative maximum BED3 to the pulmonary artery less than 175 Gy appears to be safe.

Early PET/CT scans for assessing treatment responses of non-small cell lung cancer for SBRT boost: what to do with scans from multiple scanners.

Chemoradiation remains the standard of care for the nonsurgical treatment of advanced non-small cell lung cancer (NSCLC) but local recurrence rates of 30-40% are documented. We examined the early PET/CT responses of NSCLC treated with standard chemoradiation in a prospective single institutional trial of early 18F-2-deoxy-D-glucose-PET/CT scans to help define patients appropriate for dose escalation with SBRT. 48 patients with stage IIA, IIB or IIIA-B NSCLC with no or non-bulky (

High payload dual therapeutic-imaging nanocarriers for triggered tumor delivery.

The in vitro and in vivo characterization of an optimized formulation of nanoparticles (NPs) loaded with a high content of dexamethasone palmitate (DEX-P), a chemotherapeutic adjuvant that decreases interstitial fluid pressure in tumors, and (111) In, a signaling agent, is described. These NPs are uniform in size and composition. Single photon emission computed tomography imaging demonstrates significant tumor uptake of (111) In-labeled DEX-P NPs in tumor-bearing mice. As with many nanoparticle-based drug delivery systems, significant liver accumulation is observed. Assessment of liver histology and blood tests show no apparent hepatic or renal toxicity of the DEX-P NPs. Conversion of DEX-P to DEX occurs when DEX-P NPs are incubated with mouse plasma, human tumor homogenate and ascites from tumor bearing mice, but not with human plasma. This conversion is slower in plasma from Es1(e) ((-/-)) /SCID mice, a potential alternative animal model that better mimics humans; however, plasma from these mice are not completely devoid of esterase activity. The difference between blood and tumor esterase activity in humans facilitates the delivery of DEX-P NPs to tumors and the release of dexamethasone by an esterase trigger.

Carboxylesterase-triggered hydrolysis of nanoparticle PEGylating agents.

Despite the importance of PEGylation in achieving long nanoparticle circulation times, many nanoparticles are coated with PEGylating agents susceptible to enzymatic degradation. In this study, solid lipid nanoparticles (SLNs) prepared with ester-containing compounds were evaluated for their stability in the presence of carboxylesterase. SLN suspensions became turbid within 30 min of enzymatic exposure, indicating possible disassociation of a portion of the nanoparticles. The particle size of SLNs incubated with the enzyme was smaller than the size of controls, although their morphologies appeared similar in transmission electron microscopy images. Although SLNs offered some protection over micelles, PEG6000 monostearate was rapidly degraded within 15 min. Hydrolysis of polysorbate 60 was much slower, reaching only 36% in 2 h. These studies reveal the importance of confirming the stability of PEG surface coatings prior to undertaking in vivo experiments in small animal models, which can have considerably higher plasma esterase activity than humans.

Exploring geographic variation in lung cancer incidence in Kentucky using a spatial scan statistic: elevated risk in the Appalachian coal-mining region.

OBJECTIVES: We examined geographic patterns of lung cancer incidence in Kentucky. Recent research has suggested that the coal-mining industry contributes to lung cancer risk in Appalachia. We focused on the southeastern portion of the state, which has some of the highest lung cancer rates in the nation. METHODS: We implemented a spatial scan statistic to identify areas with lung cancer incidence rates that were higher than expected, after adjusting for age, gender, and smoking. The Kentucky Cancer Registry supplied information on cases (1995-2007). The U.S. Census (2000) and several years of Behavioral Risk Factor Surveillance System data (1996-2006) provided county-level population and smoking data. We compared the results with coal-mining data from the Mining Safety and Health Administration and public water utility data from the Kentucky Division of Water. RESULTS: We identified three clusters of counties with higher-than-expected rates. Cluster 1 (relative risk [RR] = 1.21, p<0.01) included 12 counties in southeastern Kentucky. Cluster 2 (RR=1.17, p<0.01) included three nearby counties in the same region. Several of the 15 counties in Cluster 3 (RR=1.04, p=0.01) were part of the Louisville, Kentucky, or Cincinnati, Ohio, metropolitan areas. All of the counties in Clusters 1 and 2 produced significant amounts of coal. CONCLUSION: Environmental exposures related to the coal-mining industry could contribute to the high incidence of lung cancer in southeastern Kentucky. Lack of evidence for this effect in western Kentucky could be due to regional differences in mining practices and access to public water utilities. Future research should collect biological specimens and environmental samples to test for the presence of trace elements and other lung carcinogens.

Physicochemical characterization of nanotemplate engineered solid lipid nanoparticles.

As the physicochemical characteristics of solid lipid nanoparticles (SLNs) play a critical role in their success, it is important to understand how the materials and process used in their preparation affect these properties. In this study, two stearyl alcohol-based formulations were prepared using nanotemplate engineering technology and characterized. Both formulations were of a small particle size (<100 nm), ellipsoidal shape, and low polydispersity. (1)H NMR spectroscopy confirmed that the SLNs have the expected solid core structure and PEGylated surface. Analysis of the bulk materials indicated that a number of complex interactions are present among the SLN components, including a eutectic between stearyl alcohol and Brij 78. The decreased crystallinity resulting from these interactions may allow for enhanced drug loading. Physiological stability was identified and confirmed as a potential problem due to the low melting point of the eutectic. However, it is expected that with appropriate formulation modifications nanotemplate engineered SLNs will possess the properties necessary for a successful drug delivery system.

Uniformity of drug payload and its effect on stability of solid lipid nanoparticles containing an ester prodrug.

Nanocarrier systems are frequently characterized by their size distribution, while drug encapsulation in nanocarriers is generally characterized in terms of an entire population, assuming that drug distribution is uniform. Careful characterization of nanocarriers and assessment of their behavior in biological environments are essential for adequate prediction of the fate of the nanoparticles in vivo. Solid lipid nanoparticles containing [(3)H]-dexamethasone palmitate (an ester prodrug) and [(14)C]-stearyl alcohol (a component of the nanoparticle matrix) were prepared using the nanotemplate engineering method for bioresponsive tumor delivery to overcome interstitial fluid pressure gradients, a physiological barrier to tumor uptake of chemotherapeutic agents. While particle size analysis indicated a uniform size distribution of 93.2 ± 0.5 nm, gel filtration chromatography (GFC) revealed two nanoparticle populations. Drug encapsulation efficiency was 97%, but it distributed differently in the two populations, with average drug/lipid ratios of 0.04 and 0.25, respectively. The difference in surface properties resulted in distinguishing protein adsorption features of the two populations. GFC and HPLC profiles of the mixture of nanoparticles and human serum albumin (HSA) showed that no HSA was adsorbed to the first population of nanoparticles, but minor amounts were adsorbed to the second population. After 24 h incubation in 50% human plasma, ≥80% of the [(3)H]-dexamethasone palmitate was associated with nanoparticles. Thus, characterization of solid lipid nanoparticles produced by this method may be challenging from a regulatory perspective, but the strong association of the drug with the nanoparticles in plasma indicates that this nanocarrier system has the potential for in vivo application.

Phase I pharmacokinetic and pharmacodynamic study of the oral MAPK/ERK kinase inhibitor PD-0325901 in patients with advanced cancers.

PURPOSE: To determine tolerability, pharmacokinetics, and pharmacodynamics of PD-0325901, a highly potent, selective, oral mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase 1/2 inhibitor in advanced cancer patients. EXPERIMENTAL DESIGN: Sixty-six patients received PD-0325901 at doses from 1 mg once daily to 30 mg twice daily (BID). Cycles were 28 days; three administration schedules were evaluated. Pharmacokinetic parameters were assessed and tumor biopsies were done to evaluate pharmacodynamics. RESULTS: Common adverse events were rash, diarrhea, fatigue, nausea, and visual disturbances including retinal vein occlusion (RVO; n = 3). Neurotoxicity was frequent in patients receiving >or=15 mg BID. The maximum tolerated dose, 15 mg BID continuously, was associated with late-onset RVO outside the dose-limiting toxicity window. An alternative dose and schedule, 10 mg BID 5 days on/2 days off, was therefore expanded; one RVO event occurred. Three of 48 evaluable patients with melanoma achieved confirmed partial responses; 10 had stable disease >or=4 months. PD-0325901 exposure was generally dose proportional. Doses >or=2 mg BID consistently caused >or=60% suppression of phosphorylated ERK in melanoma. Fifteen patients showed significant decreases (>or=50%) in Ki-67. CONCLUSIONS: PD-0325901 showed preliminary clinical activity. The maximum tolerated dose, based on first cycle dose-limiting toxicities, was 15 mg BID continuously. However, 10 and 15 mg BID continuous dosing and 10 mg BID 5 days on/2 days off schedules were associated with delayed development of RVO; thus, further enrollment to this trial was stopped. Intermittent dose scheduling between 2 and 10 mg BID should be explored to identify a recommended dose with long-term PD-0325901 use.

A phase I study of 7-t-butyldimethylsilyl-10-hydroxycamptothecin in adult patients with refractory or metastatic solid malignancies.

PURPOSE: 7-t-Butyldimethylsilyl-10-hydroxycamptothecin (AR-67) is a novel third generation camptothecin selected for development based on the blood stability of its pharmacologically active lactone form and its high potency in preclinical models. Here, we report the initial phase I experience with i.v. AR-67 in adults with refractory solid tumors. EXPERIMENTAL DESIGN AND METHODS: AR-67 was infused over 1 hour daily five times, every 21 days, using an accelerated titration trial design. Plasma was collected on the 1st and 4th day of cycle 1 to determine pharmacokinetic parameters. RESULTS: Twenty-six patients were treated at nine dosage levels (1.2-12.4 mg/m(2)/d). Dose-limiting toxicities were observed in five patients and consisted of grade 4 febrile neutropenia, grade 3 fatigue, and grade 4 thrombocytopenia. Common toxicities included leukopenia (23%), thrombocytopenia (15.4%), fatigue (15.4%), neutropenia (11.5%), and anemia (11.5%). No diarrhea was observed. The maximum tolerated dosage was 7.5 mg/m(2)/d. The lactone form was the predominant species in plasma (>87% of area under the plasma concentration-time curve) at all dosages. No drug accumulation was observed on day 4. Clearance was constant with increasing dosage and hematologic toxicities correlated with exposure (P < 0.001). A prolonged partial response was observed in one subject with non-small cell lung cancer. Stable disease was noted in patients with small cell lung cancer, non-small cell lung cancer, and duodenal cancer. CONCLUSIONS: AR-67 is a novel, blood-stable camptothecin with a predictable toxicity profile and linear pharmacokinetics. The recommended phase II dosage is 7.5 mg/m(2)/d five times every 21 days.

Historical demography and phylogeography of a specialist bark beetle, Dendroctonus pseudotsugae Hopkins (Curculionidae: Scolytinae).

Contemporary distribution of North American species has been shaped by past glaciation events during the Quaternary period. However, their effects were not as severe in the southern Rocky Mountains and Northern Mexico as elsewhere in North America. In this context, we test hypotheses about the historical demography of Dendroctonus pseudotsugae, based on 136 haplotypes of mitochondrial cytochrome oxidase I. The phylogenetic analysis yielded four haplogroups corresponding to northwestern United States and southwestern Canada (NUS), southwestern United States (Arizona, SUS), northwestern Mexico (Sierra Madre Occidental, SMOC), and northeastern Mexico (Sierra Madre Oriental, SMOR). Predictions of demographic expansion were examined through neutrality tests against population growth and mismatch distribution. Results showed that the NUS and SMOC haplogroups have experienced demographic expansion events, whereas the SUS and SMOR haplogroups have not. Divergence times between pairs of haplogroups were estimated from early to middle Pleistocene. The longer divergence time between NUS and all other haplogroups could be the result of refugia within the Pacific Northwest and northern Rocky Mountains and long-term isolation from southernmost populations in Mexico. The results obtained in this study are in agreement with the evolutionary history of the host Douglas-fir, as the warmer climates of interglacial periods pushed conifers northward of Colorado, New Mexico, and Arizona, whereas environmental changes reduced the population size of Douglas-fir and forced fragmentation of distribution range southward into northern Mexico.

Effect of geographic isolation on genetic differentiation in Dendroctonus pseudotsugae (Coleoptera: Curculionidae).

Genetic structure of phytophagous insects has been widely studied, however, relative influence of the effect of geographic isolation, the host plant or both has been subject of considerable debate. Several studies carried out on bark beetles in the genus Dendroctonus evaluated these factors; nonetheless, recent evidence has shown that genetic structuring is a more complex process. Our goal was to examine the effect of geographic isolation on genetic structure of the Douglas-fir beetle Dendroctonus pseudotsugae. We used mtDNA cytochrome oxidase I (COI) sequences and RAPD markers. One hundred-seventy-two individuals were obtained from 17 populations, for which we analyzed 60 haplotypes (among 172 sequences of COI gene, 550 bp long) and 232 RAPD markers (7 primers). Analyses of molecular variance (AMOVA and SAMOVA), F-statistics and linear regressions suggest that the genetic structure of D. pseudotsugae is strongly influenced by geographic distance. We found that D. pseudotsugae has high intra- and inter-population genetic variation compared with several other bark beetles. Genetic differences among populations based on COI and RAPD markers were correlated with geographic distance. The observed genetic differences between northern (Canada-USA) and southern (Mexico) populations on Pseudotsuga menziesii var. glauca confirm that these two sets of populations correspond to previously assigned subspecies.

Intensive anti-inflammatory therapy with dexamethasone in patients with non-small cell lung cancer: effect on chemotherapy toxicity and efficacy.

BACKGROUND: Our preclinical and clinical data suggest that pretreatment with dexamethasone 4 days prior to chemotherapy increased the efficacy and decreased the toxicity of carboplatin and gemcitabine. To translate these findings to patients, we have undertaken a Phase 1/2 clinical trial. METHODS: Thirty patients with advanced non-small cell lung cancer (NSCLC) received gemcitabine, 1,000 mg/m(2) on days 1 and 8, and carboplatin, AUC 5.5 on day 1. Patients were randomized (1:2:2) to receive, no dexamethasone (cohort 1), or oral dexamethasone at 8 mg (cohort 2) or 16 mg (cohort 3) twice per day, 4 days before and of the day of chemotherapy. Dexamethasone was administered to patients in cohorts 2 and 3 during courses 2-4. RESULTS: In cohorts 1, 2, and 3, patients completing four planned courses of therapy were: 1/6, 6/12, 9/12. Partial responses (RECIST) were: 2/6, 6/12, and 7/12. Overall, dexamethasone significantly improved AGC and platelet nadirs and recovery times. There were no significant differences in non-hematologic toxicities between cohorts and no significant differences in pharmacokinetic parameters between course 1 and 2 in any cohort. CONCLUSIONS: These data support our previous preclinical and clinical observations that dexamethasone pre-treatment decreases hematopoietic toxicity and improves efficacy of this chemotherapeutic regimen in patients with metastatic non-small cell lung cancer and suggests that further randomized trials should be undertaken.

Nanoparticles containing anti-inflammatory agents as chemotherapy adjuvants: optimization and in vitro characterization.

The pre-administration of dexamethasone (DEX) has previously been shown to enhance the anti-tumor efficacy of chemotherapeutic agents. The delivery of anti-inflammatory agents specifically to tumors via nanoparticle carriers is expected to promote the effectiveness of chemotherapeutic agents while avoiding systemic toxicities. The process for preparing solid lipid nanoparticles containing anti-inflammatory agents using the nanotemplate engineering method was optimized. Due to the solubilization of DEX in the bulk aqueous phase, its more lipophilic palmitate ester was synthesized and incorporated in nanoparticles that included a pegylating agent, PEG6000 mono-stearate, as part of the formulation. The stealth properties of these nanoparticles were demonstrated to be enhanced compared to latex particles by measuring the adsorption of radioiodinated IgG (185 microg vs. 6.7 microg IgG/mg NP). In addition, the uptake of (14)C-labeled nanoparticles by murine macrophages was shown to decrease from 36.6% to 14.7% of the nanoparticles/mg cell protein as the amount of pegylating agent in the formulation increased from 0 to 4 mg/mL. The high loading values and low burst effect observed for these DEX palmitate-containing nanoparticles in addition to their stealth properties are expected to allow for the delivery of sufficient amounts of DEX to tumors to enhance the uptake of chemotherapeutic agents.

Recurrent implantation failure: definition.

PURPOSE: An attempt to define recurrent implantation failure. METHODS: Literature review. RESULTS: Numerous definitions of recurrent implantation failure exist. The complexity and redundancy of the process of implantation makes a single definition difficult to determine. CONCLUSION: Each center must establish a definition of recurrent implantation failure based upon the data from that center. The definition of RIF used in our program requires the transfer of > or = 8, 8-cell stage embryos or > or = 5 blastocyst embryos.