Clinical outcomes of gamma-irradiated sterile cornea in aqueous drainage device surgery: a multicenter retrospective study.

PurposeThe purpose of the study was to evaluate the safety and efficacy of gamma-irradiated sterile cornea (GISC) for covering the tube in aqueous drainage device (ADD) surgery in a retrospective, multicenter case series.Patients and methodsParticipants included 297 patients (321 procedures) who had undergone ADD surgery for the first time using GISC patch at three clinic centers in the United States between April 2009 and July 2012. The medical records of those consecutive patients were reviewed. Preoperative, intraoperative, and postoperative parameters about GISC were collected and analyzed. The main outcome measures were patch graft failure (PGF) and postoperative complications related to GISC.ResultsThree hundred and nineteen eyes in 295 patients were included in the current analysis. Ten out of the 319 eyes experienced PGF with a mean follow-up of 15.4±9.8 (SD) months. The overall cumulative PGF proportion from Kaplan-Meier analysis was 2.6% (95% CI: 0.6-4.7%) at 18 months. We detected two cases of presumed endophthalmitis related to PGF.ConclusionsGISC appears to have a reasonable success rate for preventing tube exposure related to PGF over an 18-month period. This success rate, in combination with other features of GISC (transparency and storage at room temperature), makes it a viable choice for patch graft material during ADD.

Genetic alteration associated with chronic lymphocytic leukemia.

The genetics of B-cell chronic lymphocytic leukemia (B-CLL) differ considerably from most other forms of hematologic malignancy which are usually characterized by chromosome translocations. B-CLL typically contains chromosomal deletions and chromosomes 13q14 and 11q22-->q23 are the most common. These two regions appear to share a common ancestral origin (Auer et al., 2007b). Overall, chromosomal abnormalities can be found in the majority of patients with B-CLL when using sensitive techniques (Dohneret al., 2000) and possibly reflects an underlying predisposition, with a small but significant number of familial cases. Although single and consistent abnormalities are most common, multiple rearrangements can occur, often with disease progression (Feganetal., 1995; Dohner et al., 2000). Regions of recurrent deletion suggest the presence of tumor suppressor genes if following Knudson's theoretical 2-hit model. However, despite extensive sequencing analysis over the last decade and lack of pathogenic mutations identified, there has been a move away from this suggested hypothesis and alternative mechanisms of gene inactivation involving epigenetic silencing or haploinsufficiency may be considered as more likely in this disease. This review focuses on the common genetic abnormalities in B-CLL and relates them to some of the more recent hypotheses on inactivation of genes within these regions of deletion.

Magnetic counter-gravity flow separation of electrically prepolarised lymphoid cells.

A novel principle is proposed for a differential separation of live cells (such as leucocytes) from a main flow. A microfluidic device with planar insulated electrodes as the side walls of the channel was manufactured and tested. An array of insulated vertical conductor wires was inserted along the axis of the channel and used to impose Lorentz forces upon polarisable particles that moved with the flow. Polystyrene microspheres and lymphoid cell lines (DOHH2 and K562) were used to test the ability of the setting to impose a force field that induced consistent vertical motion. The direction of electric current was found to directly influence the number of cells or microspheres that were sampled at the surface of the flow. Lorentz force was considered to be active upon cells due to an overall polarisation of the membrane surface. The consequence of the magnetic force was that the polarised cells were moved vertically upwards (opposing gravity). The setting was effective for increasing the number of extracted cells from a main flow or for increasing the concentration of DOHH2 cells in a mixed population with K562 in culture medium. The limitations of the work parameters (potential-current) were found to be dependent upon the cell type.

Stochastic modelling of apoptosis kinetics.

Robust quantitative estimation of average whole cell mitochondrial dysfunction is a useful tool for assessing sensitivity to apoptotic stimuli induced either by novel agents, or following manipulation of apoptotic threshold by pharmacological or functional genomics approaches. We have mathematically modelled the kinetics of whole cell mitochondrial membrane potential depolarisation within a population of cells as a Bernouli transition. An exponential distribution enables the median latency preceding mitochondrial membrane potential dissipation to be derived. The kinetic model can be fitted to in vitro single cell resolution data derived from kinetic flow cytometric studies by non-linear regression. We propose that kinetic determination of cumulative frequency distributions provides a useful approach for estimating apoptosis sensitivity across cell populations over short time-frames.

Pk11195, a mitochondrial benzodiazepine receptor antagonist, reduces apoptosis threshold in Bcl-X(L) and Mcl-1 expressing human cholangiocarcinoma cells.

BACKGROUND: Cholangiocarcinoma cells express high levels of the antiapoptotic proteins Bcl-X(L) and Mcl-1 and are markedly chemo- and radioresistant. Mitochondria have emerged as central players in apoptosis. Antiapoptotic members of the Bcl-2 protein family localise to the outer mitochondrial membrane and regulate mitochondrial release of apoptogenic proteins. Mitochondrial benzodiazepine receptor (mBzR) ligands have been shown to reverse Bcl-2 action and facilitate apoptosis. AIM: We evaluated the ability of the mBzR antagonist Pk11195 to overcome preapoptotic mitochondrial dysfunction in Egi-1 and Tfk-1, two human cholangiocarcinoma cell lines expressing high levels of Bcl-X(L) and Mcl-1. MATERIALS AND METHODS: Cells growing in culture were used to perform in vitro experiments over 48-96 hours following treatment. The cytotoxic agents used were 5 fluorouracil 10 microM and etoposide (Vp16) 10 microM, together with ultraviolet and 0.5-1 Gy x ray irradiation with or without 75 microM Pk11195. Apoptosis and mitochondrial dysfunction were measured at single cell resolution by flow cytometry using the mitochondrial fluorochrome DiOC6(3). Severe combined immunodeficient non-obese diabetic (SCID-NOD) mice with subcutaneous xenografts using the Egi-1 and Tfk-1 cell lines were treated with etoposide with or without addition of Pk11195 over a 72 hour period during which time the xenograft growth patterns were monitored. RESULTS: In vitro, the effect of Pk11195 on induction of apoptosis in cholangiocarcinoma cells following stimulation by chemotherapy or radiotherapy was found to be both time and dose dependent, with Pk11195 increasing rates of apoptosis by 50-95%. Intraperitoneal administration of Pk11195 in combination with Vp16 was found to increase the growth inhibiting effects of Vp16 on xenografts during the treatment phase. PK11195 75 microM on its own had no intrinsic cytotoxic efficacy. CONCLUSION: This is the first study to demonstrate that functional antagonism of coexpressed Bcl-X(L) and Mcl-1 proteins using the mBzR antagonist Pk11195 can facilitate apoptosis in cholangiocarcinoma following chemotherapy and radiotherapy.

Molecular characterization of a myelodysplasia-associated chromosome 7 inversion.

Chromosome 7 abnormalities are observed in a wide range of myeloid disorders, particularly myelodysplasia (MDS) and acute myeloid leukaemia (AML). Monosomy 7 and 7q deletions are the most frequent abnormalities, although translocations and inversions involving 7q also occur. The region 7q22--q34 may contain as many as four distinct minimal regions of deletion (MDRs), which are thought to contain one or more myeloid tumour-suppressor genes. We have defined previously the proximal breakpoint of a constitutional 7q22--q34 inversion, carried in a cell line derived from a member of a family with a history of MDS. A YAC clone spanning this breakpoint was identified. Both inversion breakpoints have now been cloned and sequenced, placing the proximal breakpoint 40 kb centromeric to the TAC2 (tachykinin 2) gene and the distal breakpoint 42 kb telomeric to the SSBP (mitochondrial single-stranded DNA-binding protein) gene. Sequence alignments revealed small (3--4 bp) duplications at the inversion breakpoints, suggesting that the mechanism of inversion involved the creation of staggered breaks and filling in of the overhanging ends. A 190-bp Alu--Alu deletion close to the distal breakpoint was also detected and may have contributed to the inversion.

Bcl-2 resistant mitochondrial toxicity mediated by the isoquinoline carboxamide PK11195 involves de novo generation of reactive oxygen species.

Resistance to apoptosis is a major obstacle preventing effective therapy for malignancy. Mitochondria localized anti-death proteins of the Bcl-2 family play a central role in inhibiting apoptosis and therefore present valid targets for novel therapy. The peripheral benzodiazepine receptor (PBR) shares a close physical association with the permeability transition pore complex (PTPC), a pivotal regulator of cell death located at mitochondrial contact sites. In this study we investigated the cytotoxicity of the PBR ligand, PK11195, in the micromolar concentration range. PK11195 induced antioxidant inhibitable collapse of the inner mitochondrial membrane potential (DeltaPsi(m)) and mitochondrial swelling in HL60 human leukaemia cells, but not in SUDHL4 lymphoma cells (which exhibited a higher level of reduced glutathione and relative tolerance to chemotherapy or pro-oxidant induced DeltaPsi(m)dissipation). PK11195 induced the production of hydrogen peroxide that was not inhibited by Bcl-2 transfection, nor depletion of mitochondrial DNA. ROS production was however blocked by protonophore, implicating a requirement for DeltaPsi(m). Our findings suggest that PK11195-induced cytotoxicity relies upon Bcl-2 resistant generation of oxidative stress; a process only observed at concentrations several orders of magnitude higher that required to saturate its receptor.

A dynamical systems model to simulate the perturbation kinetics of gene expression by antisense oligonucleotides.

Antisense oligonucleotides owe their efficacy to an ability to induce RNase H-dependent suppression of RNA translation, for sufficient time to allow physiological proteolysis. The magnitude and time delay preceding the protein nadir concentration determine the extent and timing of maximum antisense oligonucleotide activity. Antisense oligonucleotide degradation underlies reversal of RNA downregulation. The kinetics of protein downregulation is therefore determined by the complex interaction of both ligand chemistry (nuclease stability, affinity and RNase H activation), and gene expression kinetics. Optimization of antisense oligonucleotide efficacy and experimental design requires understanding of these interactions. The kinetics of protein and RNA downregulation have therefore been simulated by analysing a two-compartment kinetic model incorporating RNase H-dependent transcript degradation. The system of nonlinear differential equations describing this model was solved numerically using Runge-Kutte integration. The timecourse solutions corresponding to the four state variables (RNA, protein, antisense/RNA heteroduplex and antisense oligonucleotide), were determined simultaneously. This allowed systematic in silico examination of the consequences of altering variables such as oligonucleotide concentration, affinity, and stability, or the scheduling of multiple transfections on RNA and protein perturbations. By providing a tool for examining antisense oligonucleotide action theoretically, this heuristic model should facilitate both the rational design and interpretation of antisense experiments.

In vivo suppression of Bcl-XL expression facilitates chemotherapy-induced leukaemia cell death in a SCID/NOD-Hu model.

Bcl-XL, a member of the Bcl-2-related anti-apoptosis protein family, antagonizes a diverse range of apoptosis-inducing stimuli by preventing mitochondrial permeability transition, release of apoptogenic factors including cytochrome C, and caspase activation. We have tested the hypothesis that the susceptibility of Bcl-XL-expressing leukaemic cells to apoptosis induced by VP16 (etoposide) can be enhanced by pharmacological downregulation of Bcl-XL in vivo. Two subcutaneous xenograft models of B-cell leukaemia-employing SEMK-2 and BV173 cell lines were established in severe combined immunodeficient/non-obese diabetic mice followed by 14 d of continuous subcutaneous administration of Bcl-XL-specific second generation oligonucleotides ISIS 16009 or ISIS 15999. Tumours were disaggregated, enabling investigation of Bcl-XL expression and apoptosis susceptibility at single-cell resolution using cytofluorimetry. Marked sequence-specific reduction of Bcl-XL was associated with sequence-specific enhancement of VP16-induced mitochondrial permeability transition, caspase-3 activation and loss of membrane asymmetry. A negative correlation between Bcl-XL expression and apoptosis susceptibility was observed, together with a positive correlation with respect to a reduced redox state. Bcl-XL downregulation reduces the threshold for VP16-induced apoptosis by potentiating mitochondrial dysfunction and its sequelae, and therefore presents a novel therapeutic strategy for reversing chemoresistance.

Role for CCG-trinucleotide repeats in the pathogenesis of chronic lymphocytic leukemia.

Chromosome 11q deletions are frequently observed in chronic lymphocytic leukemia (CLL) in association with progressive disease and a poor prognosis. A minimal region of deletion has been assigned to 11q22-q23. Trinucleotide repeats have been associated with anticipation in disease, and evidence of anticipation has been observed in various malignancies including CLL. Loss of heterozygosity at 11q22-23 is common in a wide range of cancers, suggesting this is an unstable area prone to chromosome breakage. The location of 8 CCG-trinucleotide repeats on 11q was determined by Southern blot analysis of a 40-Mb YAC and PAC contig spanning 11q22-qter. Deletion breakpoints in CLL are found to co-localize at specific sites on 11q where CCG repeats are located. In addition, a CCG repeat has been identified within the minimal region of deletion. Specific alleles of this repeat are associated with worse prognosis. Folate-sensitive fragile sites are regions of late replication and are characterized by CCG repeats. The mechanism for chromosome deletion at 11q could be explained by a delay in replication. Described here is an association between CCG repeats and chromosome loss suggesting that in vivo "fragile sites" exist on 11q and that the instability of CCG repeats may play an important role in the pathogenesis of CLL.

Antisense Bcl-2 oligonucleotide uptake in human transitional cell carcinoma.

OBJECTIVES: Antisense oligonucleotides (AO) downregulate Bcl-2 protein expression in various tumours if good target cell uptake is achieved. In this study, uptake of FITC labelled AO (FITC-AO) directed at Bcl-2 was examined in: (1) the RT4 bladder tumour cell line; (2) normal pig urothelium, and (3) human superficial bladder tumours. METHODS: In the RT4 cell line, uptake of FITC-AO, FITC-scrambled and FITC-sense oligonucleotides were quantified by flow cytometry at 4-hour intervals over 24 h. Uptake of FITC-AO was assessed in normal pig urothelium by flow cytometry after FITC-AO was infused for 1 h. Uptake of FITC AO was assessed in samples from 14 human superficial bladder tumours which were maintained in an ex vivo model. In samples from 6 tumours, uptake at 4 h was assessed using fluorescence microscopy. In samples from 8 separate tumours uptake every 4 h within the first 24-hour incubation period was assessed by flow cytometry. RESULTS: In the RT4 cell line the FITC-AO, FITC-scrambled and FITC-sense oligonucleotide uptake was similar. Disaggregated cells from the normal urothelium of the 3 pigs exhibited 33, 46 and 51% of cells staining positively for FITC-AO as determined by flow cytometry. All 6 tumour samples had detectable intracellular FITC-AO by fluorescence microscopy at 4 h. In the 8 tumours examined over the 24-hour incubation period, there was a range of percentages of positively staining cells. However, most tumours had a monotonic increase in intracellular fluorescence intensity that plateaued 16 h post-infusion. CONCLUSION: Antisense Bcl-2 oligonucleotides were readily taken up by superficial bladder cancer cells but the heterogeneous uptake in tumour samples needs to be considered when assessing the bioavailability of these drugs.

Developing performance measures for alcohol and other drug services in managed care plans. Washington Circle Group.

BACKGROUND: Monitoring the quality and availability of alcohol and other drug (AOD) services must be a central tenet of any health-related performance measurement system. The Washington Circle Group (WCG), which was convened by the Center for Substance Abuse Treatment Office of Managed Care in March 1998, has developed a core set of performance measures for AOD services for public- and private-sector health plans. It is also collaborating with a broad range of stakeholders to ensure widespread adoption of these performance measures by health plans, private employers, public payers, and accrediting organizations. CORE PERFORMANCE MEASURES: Four domains were identified, with specific measures developed for each domain: (1) prevention/education, (2) recognition, (3) treatment (including initiation of alcohol and other plan services, linkage of detoxification and AOD plan services, treatment engagement, and interventions for family members/significant others), and (4) maintenance of treatment effects. CONTINUING EFFORTS: Four measures that are based on administrative information from health plans and two measures that require a consumer survey of behavioral health care are undergoing extensive pilot testing. The WCG has reached out to a broad range of stakeholders in performance measurement and managed care to acquaint them with the measures and to promote their investigation and adoption. As results of pilot testing become available, these outreach efforts will continue. CONCLUSIONS: Performance measures for AOD services need to become an integral part of a comprehensive set of behavioral and physical health performance measures for managed care plans.

Extranodal marginal zone B-cell lymphoma genotyping by Alu-polymerase chain reaction.

DNA amplification by polymerase chain reaction (PCR) with primers designed on the widely distributed Alu sequences allows the production of specific inter-Alu DNA-fingerprints. Amplification of tumour and matched normal DNA can show differences due to genetic alterations within the tumour genome. We applied this approach to study low-grade extranodal marginal zone B-cell lymphoma (of MALT type). After digestion with restriction enzymes, DNA samples were separately amplified by PCR with three different Alu-primers. A comparison between the fingerprint pattern from lymphoma and normal samples was made. Inter-Alu bands differing between the two samples were excised from the gel, cloned and sequenced. Nine cases of low-grade MALT-lymphomas have been analysed, giving seventeen different bands between tumour and normal. DNA sequence analysis showed identities for three of them with sequences available at the GenBank. The methodology of Alu-PCR to detect DNA-based abnormalities, in addition or combination with RNA-based methods, is a powerful tool to identify candidate regions frequently altered in tumours. With the increased available genomic sequences through the Human Genome Project, there will be an increasing probability of picking up perfect homologies with these sequences using cloned differential Alu-PCR bands in BLAST searches through genome databases.

Phase I clinical and pharmacokinetic study of bcl-2 antisense oligonucleotide therapy in patients with non-Hodgkin's lymphoma.

PURPOSE: To evaluate the pharmacokinetics and toxicity of an antisense oligonucleotide targeting bcl-2 in patients with non-Hodgkin's lymphoma (NHL) and to determine efficacy using clinical and biologic end points. PATIENTS AND METHODS: Twenty-one patients with Bcl-2-positive relapsed NHL received a 14-day subcutaneous infusion of G3139, an 18-mer phosphorothioate oligonucleotide complementary to the first six codons of the bcl-2 open reading frame. Plasma pharmacokinetics were measured by anion exchange high-performance liquid chromatography. Response was assessed by computed tomography. Changes in Bcl-2 expression were measured by fluorescence-activated cell sorting of patients' tumor samples. RESULTS: Eight cohorts of patients received doses between 4. 6 and 195.8 mg/m(2)/d. No significant systemic toxicity was seen at doses up to 110.4 mg/m(2)/d. All patients displayed skin inflammation at the subcutaneous infusion site. Dose-limiting toxicities were thrombocytopenia, hypotension, fever, and asthenia. The maximum-tolerated dose was 147.2 mg/m(2)/d. Plasma levels of G3139 equivalent to the efficacious plasma concentration in in vivo models were produced with doses above 36.8 mg/m(2)/d. Plasma levels associated with dose-limiting toxicity were greater than 4 microg/mL. By standard criteria, there was one complete response, 2 minor responses, nine cases of stable disease, and nine cases of progressive disease. Bcl-2 protein was reduced in seven of 16 assessable patients. This reduction occurred in tumor cells derived from lymph nodes in two patients and from peripheral blood or bone marrow mononuclear cell populations in the remaining five patients. CONCLUSION: Bcl-2 antisense therapy is feasible and shows potential for antitumor activity in NHL. Downregulation of Bcl-2 protein suggests a specific antisense mechanism.

Co-localisation of CCG repeats and chromosome deletion breakpoints in Jacobsen syndrome: evidence for a common mechanism of chromosome breakage.

Folate-sensitive fragile sites are associated with the expansion and hypermethylation of CCG-repeats. The fragile site in 11q23.3, FRA11B, has been shown to cause chromosome deletions in vivo, its expression being associated with Jacobsen (11q-) syndrome. However, the majority of Jacobsen deletions are distal to FRA11B and are not related to its expression. To test the hypothesis that other unidentified fragile sites might be located in 11q23.3-24 and may cause these deletions, we have identified and characterised CCG-trinucleotide repeats within a 40 Mb YAC contig spanning distal chromosome 11q. Only eight CCG-repeats were identified within the entire YAC contig (not including FRA11B ), six of which map to the region of 11q23.3-24 that includes Jacobsen deletions. We have previously collated the deletion mapping data of 24 Jacobsen patients with the physical map of chromosome 11q, and accurately localised six breakpoints to short intervals corresponding to individual YAC clones. We now show that in each of these cases, YAC clones found to contain a deletion breakpoint also contain a CCG-repeat. The improved analysis of one of these deletions, together with those of several new Jacobsen cases, further strengthens this association by localising five breakpoints to individual PAC clones containing CCG-repeats. These data provide strong evidence for the non-random clustering of chromosome deletion breakpoints with CCG-repeats, and suggests that they may play an important role in a common mechanism of chromosome breakage.

Stochastic modeling of apoptosis tolerance distributions measured by multivariate flow analysis of human leukemia cells.

BACKGROUND: Cytofluorometric analysis allows single-cell resolution of all-or-none programmed cell death (apoptosis) responses and permits direct measurement of cumulative frequency distributions (CFDs) of apoptosis sensitivity from which the median apoptosis tolerance can be estimated. Robust estimation of susceptibility to apoptosis within neoplastic cell populations provides a means of either accurately determining pharmacologically induced changes in apoptosis sensitivity or comparing cell population responses to different apoptosis inducers. METHODS: Experimentally determined CFDs for VP-16 (etoposide)-induced apoptosis were measured by phosphotidylserine surface expression and mitochondrial membrane potential dissipation (DeltaPsi(m)) in BV173 leukemia cells. CFDs were modelled by a modified Hill equation using a four-parameter nonlinear regression from which median apoptosis tolerance (K) was estimated. RESULTS: Median apoptosis tolerance (K) was estimated from nonlinear regression analysis of CFDs for DeltaPsi(m) collapse and loss of membrane asymmetry. The error distribution of K determined from nonlinear regression analysis of 100 simulated CFDs was shown to exhibit an asymmetrical distribution. The asymmetrical likelihood intervals for K were computed iteratively, thereby providing a measure of experimental error. CONCLUSIONS: A distribution-based approach to apoptosis assay using multivariate flow analysis offers a powerful, quantitative technique for investigating the phenotypical basis of neoplastic cell responsiveness to apoptosis therapy, permitting separation of cell populations on the basis of apoptosis susceptibility.

Normal and chronic phase CML hematopoietic cells repopulate NOD/SCID bone marrow with different kinetics and cell lineage representation.

INTRODUCTION: Chronic myelogenous leukemia is characterized by a clonal expansion of abnormal hematopoietic cells, which eventually replaces normal hematopoiesis. We wanted to test the hypothesis that the growth kinetics of CML and normal hematopoietic cells are different. MATERIALS AND METHODS: We compared the growth kinetics and the phenotype of engraftment of chronic phase CML and normal human CD34(+) precursor cells in the bone marrow of immune deficient mice. RESULTS: High levels of engraftment of normal precursors occurred early and consisted of myeloid, erythroid, megakaryocytic, and lymphoid elements. This level and pattern of engraftment were maintained at later assessments. The level of CML cell engraftment was initially much lower, but it increased progressively at late time-points with no indication of a plateau in growth. Early engraftment of CML cells consisted almost entirely of myeloid and mast cells but soon after only mast cells were detectable. Conversely mast cells were infrequent in mice engrafted with normal progenitors. CONCLUSION: We conclude that in contrast to normal cell engraftment, engraftment of CML cells in NOD/SCID mice is characterized by a slow but progressive myeloid infiltration, which eventually consists almost entirely of mast cells.

Antisense-mediated suppression of Bcl-2 highlights its pivotal role in failed apoptosis in B-cell chronic lymphocytic leukaemia.

Although advances have been made in the development of more effective treatment modalities, B-cell chronic lymphocytic leukaemia (B-CLL) remains incurable due to the development of drug resistance. Defective programmed cell death mechanisms rather than dysregulation of cell cycle appears to predominate in B-CLL and it is likely that a failure to initiate apoptosis contributes to chemoresistance. Most B-CLL cells contain high levels of the anti-apoptotic protein Bcl-2 and high Bcl-2/Bax ratios have been associated with in vitro resistance to cytotoxic agents. In this study we evaluated the cellular responses to a Bcl-2 antisense oligonucleotide in terms of Bcl-2 mRNA and protein expression and the induction of apoptosis. The antisense molecule induced a specific reduction in Bcl-2 mRNA and protein expression over the 48 h culture period and was associated with increased apoptosis. The study indicates that Bcl-2 protein is central to the mediation of resistance to apoptosis in B-CLL. Therefore Bcl-2 antisense oligonucleotides might be useful in the treatment of B-CLL.