Antiviral Properties of Chemical Inhibitors of Cellular Anti-Apoptotic Bcl-2 Proteins.

Viral diseases remain serious threats to public health because of the shortage of effective means of control. To combat the surge of viral diseases, new treatments are urgently needed. Here we show that small-molecules, which inhibit cellular anti-apoptotic Bcl-2 proteins (Bcl-2i), induced the premature death of cells infected with different RNA or DNA viruses, whereas, at the same concentrations, no toxicity was observed in mock-infected cells. Moreover, these compounds limited viral replication and spread. Surprisingly, Bcl-2i also induced the premature apoptosis of cells transfected with viral RNA or plasmid DNA but not of mock-transfected cells. These results suggest that Bcl-2i sensitizes cells containing foreign RNA or DNA to apoptosis. A comparison of the toxicity, antiviral activity, and side effects of six Bcl-2i allowed us to select A-1155463 as an antiviral lead candidate. Thus, our results pave the way for the further development of Bcl-2i for the prevention and treatment of viral diseases.

Long-term antipsychotic and benzodiazepine use and brain volume changes in schizophrenia: The Northern Finland Birth Cohort 1966 study.

High doses of antipsychotics have been associated with loss in cortical and total gray matter in schizophrenia. However, previous imaging studies have not taken benzodiazepine use into account, in spite of evidence suggesting adverse effects such as cognitive impairment and increased mortality. In this Northern Finland Birth Cohort 1966 study, 69 controls and 38 individuals with schizophrenia underwent brain MRI at the ages of 34 and 43 years. At baseline, the average illness duration was over 10 years. Brain structures were delineated using an automated volumetry system, volBrain, and medication data on cumulative antipsychotic and benzodiazepine doses were collected using medical records and interviews. We used linear regression with intracranial volume and sex as covariates; illness severity was also taken into account. Though both medication doses associated to volumetric changes in subcortical structures, after adjusting for each other and the average PANSS total score, higher scan-interval antipsychotic dose associated only to volume increase in lateral ventricles and higher benzodiazepine dose associated with volume decrease in the caudate nucleus. To our knowledge, there are no previous studies reporting associations between benzodiazepine dose and brain structural changes. Further studies should focus on how these observations correspond to cognition and functioning.

Longitudinal changes in total brain volume in schizophrenia: relation to symptom severity, cognition and antipsychotic medication.

Studies show evidence of longitudinal brain volume decreases in schizophrenia. We studied brain volume changes and their relation to symptom severity, level of function, cognition, and antipsychotic medication in participants with schizophrenia and control participants from a general population based birth cohort sample in a relatively long follow-up period of almost a decade. All members of the Northern Finland Birth Cohort 1966 with any psychotic disorder and a random sample not having psychosis were invited for a MRI brain scan, and clinical and cognitive assessment during 1999-2001 at the age of 33-35 years. A follow-up was conducted 9 years later during 2008-2010. Brain scans at both time points were obtained from 33 participants with schizophrenia and 71 control participants. Regression models were used to examine whether brain volume changes predicted clinical and cognitive changes over time, and whether antipsychotic medication predicted brain volume changes. The mean annual whole brain volume reduction was 0.69% in schizophrenia, and 0.49% in controls (p = 0.003, adjusted for gender, educational level, alcohol use and weight gain). The brain volume reduction in schizophrenia patients was found especially in the temporal lobe and periventricular area. Symptom severity, functioning level, and decline in cognition were not associated with brain volume reduction in schizophrenia. The amount of antipsychotic medication (dose years of equivalent to 100 mg daily chlorpromazine) over the follow-up period predicted brain volume loss (p = 0.003 adjusted for symptom level, alcohol use and weight gain). In this population based sample, brain volume reduction continues in schizophrenia patients after the onset of illness, and antipsychotic medications may contribute to these reductions.

SU-E-J-169: 4D-PET for Abdominal Tumor Target Volume Generation.

PURPOSE: To examine the impact of 4D-PET on target volume delineation of upper-abdominal tumors, versus conventional un-gated PET. METHODS: Four patients with upper-abdominal tumors underwent respiratory-correlated FDG PET/CT scanning (4D-PET) as part of a continuing IRB-approved research protocol. Internal target volumes of FDG-avid tumors were contoured on the 4D-PET and conventional un-gated PET by a radiation oncologist who is a specialist in gastro-intestinal tumors. To create the 4D-PET ITV, the end-inhale and end-exhale 4D-PET phases were used. The relative volumes and volumetric overlaps of the 4D and un-gated target volumes were examined. Additionally, 4D-PET was used to measure the motion of the tumors. RESULTS: Of the four patients who were imaged, one showed minimal motion (〈 3 mm in any direction) and one showed minimal FDG avidity; these were removed from further analysis. Of the two tumors which showed significant motion and FDG uptake, 4D-PET volumes were 28% and 21% larger than un-gated PET volumes. The un-gated PET volumes were almost entirely contained within the 4D-PET volumes (95% and 93% for the two tumors). Tumors appeared to deform as well as translate with breathing, although this could be due to varying intra-gate motion rather than actual physiological deformation. The superior-inferior borders of the tumors exhibited the most motion, with displacements of 5.6 mm and 6.4 mm. CONCLUSIONS: 4D-PET can be used to estimate the motion of FDG-avid upper-abdominal tumors. Use of 4D-PET increases the size of target volumes compared to un-gated PET in a subset of upper-abdominal cancer patients. Direct measurement of tumor motion and deformation by 4D-PET imaging could allow the use of patient-specific margins rather than population-based margins, potentially leading to increased target coverage and reduced normal tissue irradiation.

WE-G-213CD-02: 4D-PET Maximum Intensity Projections Improve Accuracy of Mobile Tumor Volume Delineation.

PURPOSE: To examine the efficacy and accuracy of respiratory-gated positron emission tomography (4D-PET) maximum intensity projections (MIPs) in segmenting mobile tumor internal target volumes (ITVs) through a phantom study. METHODS: An acrylic phantom was used for PET list-mode acquisition, consisting of 11C-filled spheres affixed inside a cylinder containing an 18-fluorodeoxyglucose solution. The phantom was attached to a robotic arm that underwent 1D motion based on clinically-derived patient breathing trajectories. An amplitude-based gating was performed on sequential list-mode sub-files of varying signal-to-background ratios, and PET-MIPs were generated from the gated images. ITVs were segmented by first denoising and deblurring images using a custom post-processing module and then applying an absolute SUV threshold. ITV accuracy was assessed using the volume recovery fraction (VRF) - the ratio of measured ITV to true volume occupied by the moving phantom spheres - which was used to compare PET-MIP, ungated PET, and static sphere images. In addition, the effects of tumor trajectories, number of gating windows, and margin additions were investigated. RESULTS: VRFs of ITVs generated from PET-MIPs were consistently higher than those from ungated PET. They also demonstrated a closer agreement to VRFs of static spheres (up to 99% similarity vs. 72% for ungated PET), suggesting that tumor motion had very little effect on the accuracy of PET-MIP measurements. Trajectories with higher amplitude and baseline drift decreased VRF by up to 14% for both PET-MIP and ungated PET. Increasing the number of gating windows (up to eight windows) resulted in higher VRFs for PET-MIPs without producing excessive image noise. PET-MIPs required a smaller margin addition than ungated PET to achieve a better overlap with the ground truth ITV. CONCLUSIONS: Compared to ungated PET, PET-MIPs are not significantly affected by tumor motion. 4D-PET imaging is a promising and viable methodology to better delineate mobile tumor volumes.

Evaluation of sequentially crosslinked ultra-high molecular weight polyethylene.

This study was undertaken to investigate the effect of crosslinking ultra-high molecular weight polyethylene (UHMWPE) in a sequential manner to the final desired dose and to compare the results to single-dose crosslinking. To verify these results, an explanted, commercially available, sequentially crosslinked component was characterized. Finally, additional tensile testing was conducted to determine if tensile-sample thickness has a significant effect on the mechanical properties of UHMWPE. Based upon this well-controlled study with the same starting material, there is no apparent benefit of sequential crosslinking over crosslinking by single dose in any of the mechanical, thermophysical, physical, or oxidative properties evaluated in this study. In contrast, the soak temperature of the postirradiation heat treatment was more influential and exhibited statistically significant effects on the stability, structure, and properties of the resultant material. Compared to virgin material, crosslinking always resulted in decreases in tensile strength, elongation, and impact strength. These results were confirmed by characterization of a retrieved, sequentially crosslinked (X3) cup. All of the metrics derived for the retrieved cup were virtually identical to the sequential- and single-dose-crosslinked materials produced in this study. Examination of the effect of tensile-sample thickness demonstrated that there are significant effects on the resultant properties. In particular, the ultimate tensile strength of UHMWPE can be elevated by conducting tensile tests with thin specimens.

Inspiratory flow shape clustering: an automated method to monitor upper airway performance during sleep.

We describe an automated method for monitoring airflow dynamics in the upper airway of a sleeping subject. Its main task is to determine a set of inspiratory flow shape representatives and their relative incidence in a given respiratory airflow material. The flow shape clustering aims at reducing redundant information in the data, and thereby decreases the time needed to score overnight sleep recordings. Compared with previous computer-assisted systems, built on a pre-defined classification of prototype shapes, we require no a priori assumptions of the flow shape clusters to be discovered. The intrinsic flow shape clustering is performed with a modification of the Isodata algorithm, and the K-means clustering is used as a reference in comparison studies. The operation of the method is demonstrated on clinical sleep recordings both from patients with nocturnal breathing disorders and from non-symptomatic individuals. The feasible results obtained in the practical research design suggest that application of clustering algorithms to respiratory airflow measurements could give important insights into the subtle flow shape abnormalities underlying obstructive sleep-disordered breathing.

Particle analysis for the determination of UHMWPE wear.

Three types of ultrahigh molecular weight polyethylene (UHMWPE) acetabular liners were tested against cobalt-chrome (CoCr) femoral heads on a hip simulator to approximately 20 million cycles. The materials included (1) conventional, nonirradiated liners (C-PE); (2) 5 Mrad gamma-irradiated, remelted, and artificially aged liners (5-XPE); and (3) 10 Mrad gamma-irradiated, remelted, and artificially aged liners (10-XPE). Wear was quantified by gravimetric analysis and wear particle characterization. Particle number and morphology were quantified by scanning electron microscopy (SEM) and compared between groups. Atomic force microscopy (AFM) was used to measure particle height in an effort to improve the total wear volume estimation. The wear debris, as characterized by SEM, was predominantly submicron and round, with occasional fibrils documented in the C-PE material. AFM analysis showed that particle height was approximately one-third of the particle equivalent circular diameter for all three materials. This correlation was used to improve the estimation of volumetric wear rate through SEM particle analysis. This technique is particularly useful for high-dose crosslinked UHMWPE, such as 10-XPE, which show weight gain due to fluid absorption during wear testing. This study has shown that particle analysis provides additional particle morphology and quantity information that cannot be obtained through gravimetric analysis.

Detection of -lactamases in nosocomial gram negative clinical isolates.

-lactamases represent the most common mechanism of -lactam resistance. Extended spectrum -lactamases (ESBLs) represent a major group of -lactamases currently being identified worldwide in large numbers along with inducible AmpC -lactamases and derepressed mutants. The present study was done to detect -lactamase production in clinical isolates by rearranging routine discs used in reporting susceptibility to specifically assess ESBLs, AmpC -lactamases (both inducible and hyperproducers i.e., derepressed mutants). A total of 286 clinical isolates were studied using a novel predictor disc approximation method to detect the above mechanisms of resistance with careful use and placement of antimicrobial discs. Of the 286 isolates, 151(53%) were ESBL producers of which 131(46%) were also derepressed mutants while remaining 20(7%) were plain ESBL producers. Forty (14%) were plain derepressed mutants. Inducible AmpC -lactamase production was detected in 19(7%) of the isolates. The commonest ESBL producers were E.coli and K. pneumoniae. The high incidence of -lactamase production due to multiple mechanisms in clinical isolates is alarming and urgent action needs to be taken from both a therapeutic and infection control perspective.

Relationship between gravimetric wear and particle generation in hip simulators: conventional compared with cross-linked polyethylene.

Hip-simulator studies have shown reduced gravimetric wear rates for inert-gas gamma-irradiated ultra-high molecular weight polyethylene when compared with conventional ethylene-oxide-sterilized ultra-high molecular weight polyethylene. Analysis shows a greater number of particles generated from inert-gas gamma-irradiated ultra-high molecular weight polyethylene. This study was undertaken to examine particle-generation rates of polyethylene with different levels of cross-linking and to correlate them with gravimetric wear data. Particle-generation rates did not correlate with gravimetric wear rates. Particle analysis should be performed to predict the in vivo behavior of bearing surface materials. Cross-linked ultra-high molecular weight polyethylene subjected to 10 Mrad (100,000 Gy) of gamma irradiation generated significantly fewer particles than ethylene-oxide-sterilized ultra-high molecular weight polyethylene; it also demonstrated a 96% reduction in the volume of particles.

Comparison of three joint simulator wear debris isolation techniques: acid digestion, base digestion, and enzyme cleavage.

Quantification of ultrahigh molecular weight polyethylene (UHMWPE) wear debris remains a challenging task in orthopedic device analysis. Currently, the weight loss method is the only accepted practice for quantifying the amount of wear generated from a PE component. This technique utilizes loaded soak controls and weight differences to account for polymeric material lost through wear mechanisms. This method enables the determination of the amount of wear in the orthopedic device, but it provides no information about debris particulate size distribution. In order to shed light on wear mechanisms, information about the wear debris and its size distribution is necessary. To date, particulate isolation has been performed using the base digestion technique. The method uses a strong base, ultracentrifugation, and filtration to digest serum constituents and to isolate PE debris from sera. It should be noted that particulate isolation methods provide valuable information about particulate size distribution and may elucidate the mechanisms of wear associated with polymeric orthopedic implants; however, these techniques do not yet provide a direct measure of the amount of wear. The aim of this study is to present alternative approaches to wear particle isolation for analysis of polymer wear in total joint replacements without recourse to ultracentrifugation. Three polymer wear debris isolation techniques (the base method, an acid treatment, and an enzymatic digestion technique) are compared for effectiveness in simulator studies. A requirement of each technique is that the wear particulate must be completely devoid of serum proteins in order to effectively image and count these particles. In all methods the isolation is performed through filtration and chemical treatment. Subsequently, the isolated polymer particles are imaged using scanning electron microscopy and quantified with digital image analysis. The results from this study clearly show that isolation can be performed without the use of ultracentrifugation and that these methods provide a viable option for wear debris analysis.

Radioisotopes and dosimetry in vascular brachytherapy.

This chapter summarizes the current status of available isotopes for vascular brachytherapy. The physics and dosimetric aspects of current and new sources would have a great deal of influence in the outcome of clinical trials and eventual success of brachytherapy in treating vascular disease.

Radiation therapy to inhibit restenosis: early clinical results.

BACKGROUND: Although several early trials indicate that treatment of restenosis with radiation therapy is safe and effective, the long-term impact of this new technology has been questioned. The objective of this report is to document angiographic and clinical outcome 3 years after treatment of restenosis of stented coronary arteries with catheter-based iridium-192 (192Ir). METHODS: A double-blind, randomized trial compared 192Ir with placebo sources in patients with previous restenosis after coronary angioplasty. Over a 9-month period, 55 patients were enrolled; 26 were randomized to 192Ir and 29 to placebo. RESULTS: At 3-year follow-up, target-lesion revascularization was significantly lower in the 192Ir group (15.4% vs. 48.3%; p < 0.01). The dichotomous restenosis rate at 3-year follow-up was also significantly lower in 192Ir patients (33% vs. 64%; p < 0.05). In a subgroup of patients with 3-year angiographic follow-up not subjected to target-lesion revascularization by the 6-month angiogram, the mean minimal luminal diameter between 6 months and 3 years decreased from 2.49 +/- 0.81 mm to 2.12 +/- 0.73 mm in 192Ir patients, but was unchanged in placebo patients. CONCLUSIONS: The early clinical benefits observed after treatment of coronary restenosis with 192Ir appear durable at late follow-up. Angiographic restenosis continues to be significantly reduced in 192Ir-treated patients, but a small amount of late loss was observed between the 6-month and 3-year follow-up time points. No events occurred in the 192Ir group to suggest major untoward effects of vascular radiotherapy. At 3-year follow-up, vascular radiotherapy continues to be a promising new treatment for restenosis.

Localized intracoronary gamma-radiation therapy to inhibit the recurrence of restenosis after stenting.

BACKGROUND: Although the frequency of restenosis after coronary angioplasty is reduced by stenting, when restenosis develops within a stent, the risk of subsequent restenosis is greater than 50 percent. We report on a multicenter, double-blind, randomized trial of intracoronary radiation therapy for the treatment of in-stent restenosis. METHODS: Of 252 eligible patients in whom in-stent restenosis had developed, 131 were randomly assigned to receive an indwelling intracoronary ribbon containing a sealed source of iridium-192, and 121 were assigned to receive a similar-appearing nonradioactive ribbon (placebo). RESULTS: The primary end point, a composite of death, myocardial infarction, and the need for repeated revascularization of the target lesion during nine months of follow-up, occurred in 53 patients assigned to placebo (43.8 percent) and 37 patients assigned to iridium-192 (28.2 percent, P=0.02). However, the reduction in the incidence of major adverse cardiac events was determined solely by a diminished need for revascularization of the target lesion, not by reductions in the incidence of death or myocardial infarction. Late thrombosis occurred in 5.3 percent of the iridium-192 group, as compared with 0.8 percent of the placebo group (P=0.07), resulting in more late myocardial infarctions in the iridium-192 group (9.9 percent vs. 4.1 percent, P=0.09). Late thrombosis occurred in irradiated patients only after the discontinuation of oral antiplatelet therapy (with ticlopidine or clopidogrel) and only in patients who had received new stents at the time of radiation treatment. CONCLUSIONS: Intracoronary irradiation with iridium-192 resulted in lower rates of clinical and angiographic restenosis, although it was also associated with a higher rate of late thrombosis, resulting in an increased risk of myocardial infarction. If the problem of late thrombosis within the stent can be overcome, intracoronary irradiation with iridium-192 may become a useful approach to the treatment of in-stent restenosis.

Early lumen loss after repeat coronary intervention for in-stent restenosis.

The purpose of this study was to compare the effects of balloon angioplasty versus repeat stenting on the early angiographic outcome in patients with in-stent restenosis. The treatment of in-stent restenosis using balloon angioplasty alone often yields excellent early results, but is associated with a high rate of late recurrence. In the SCRIPPS trial, patients with restenosis were treated either with balloon angioplasty alone or placement of additional stents to optimize angiographic results before randomization and exposure of the restenotic segment to gamma radiation or placebo. In patients undergoing repeat catheter based intervention for the treatment of in-stent restenosis, quantitative coronary angiography was used to compare the results of balloon angioplasty alone versus repeat stenting on early lumen loss. After a mean delay time interval of 71 min, the early loss was 0.35 +/- 0.34 mm in the balloon angioplasty alone group compared to 0.01 +/- 0.34 mm in the repeat-stenting group (P = 0.004). The early loss index in the balloon angioplasty alone group (12.8 +/- 12.9%) was significantly greater than in the repeat stenting group (0.7 +/- 12.1%; P = 0.003). Although balloon angioplasty for in-stent restenosis often provides excellent immediate angiographic results, luminal diameters are significantly reduced in the early time period after balloon dilatation. Repeat stenting nearly abolishes this early luminal loss.

How long is enough? Defining the treatment length in endovascular brachytherapy.

The International Commission on Radiation Units and Measurement (IRCU) 50 has clearly defined treatment volumes in radiation therapy in the management of neoplasms. These concepts are applied to the field of endovascular brachytherapy (EVBT) for the prevention of postangioplasty restenosis. The following definitions are proposed: gross target length (GTL) is defined as the narrowed segment of the artery that requires intervention. Clinical target length (CTL) is defined as the intervened or injured length, which could be due to angioplasty, stent strut injury, stent deployment, or debulking procedures. Planning target length (PTL) is the CTL plus a margin to account for heart/catheter movement and uncertainty in target localization. The final treatment length (TL) is the PTL plus the effect of penumbra. The accurate specification of treatment length serves several important purposes. Based on an understanding of the different factors constituting the treatment length, adequate margins can be provided beyond the GTL; this will avoid geographic misses and minimize edge failures. These definitions of target length ensure treatment consistency and provide a standard terminology for communication among practitioners of EVBT, something of critical importance in the conduct of multi-institutional trials in this new and multidisciplinary therapy. Finally, since the efficacy of EVBT is critically dependent on the precision of radiation delivery, these guidelines ensure that the benefits of EVBT seen in prospective randomized trials can be translated into daily clinical practice at the community level.