Does Loosening the Inclusion Criteria of the CROSS Trial Impact Outcomes in the Curative-Intent Trimodality Treatment of Oesophageal and Gastroesophageal Cancer Patients?

AIM: To determine the efficacy of preoperative chemoradiotherapy as per the CROSS protocol for oesophageal/gastroesophageal junction cancer (OEGEJC), when expanded to patients outside of the inclusion/exclusion criteria defined in the original clinical trial. MATERIALS AND METHODS: Data were collected retrospectively on 229 OEGEJC patients referred for curative-intent preoperative chemoradiotherapy. Outcomes including pathological complete response (pCR), overall survival (OS), cancer-specific survival and recurrence-free survival (RFS) of patients who met CROSS inclusion criteria (MIC) versus those who failed to meet criteria (FMIC) were determined. RESULTS: In total, 42.8% of patients MIC, whereas 57.2% FMIC; 16.6% of patients did not complete definitive surgery. The MIC cohort had higher rates of pCR, when compared with the FMIC cohort (33.3% versus 20.6%, P = 0.039). The MIC cohort had a better RFS, cancer-specific survival and OS compared with the FMIC cohort (P = 0.006, P = 0.004 and P = 0.009, respectively). Age >75 years and pretreatment weight loss >10% were not associated with a poorer RFS (P = 0.541 and 0.458, respectively). Compared with stage I-III patients, stage IVa was associated with a poorer RFS (hazard ratio (HR) = 2.158; 95% confidence interval (CI) = 1.339-3.480, P = 0.001). Tumours >8 cm in length or >5 cm in width had a trend towards worse RFS (HR = 2.060; 95% CI = 0.993-4.274, P = 0.052). CONCLUSION: Our study showed that the robust requirements of the CROSS trial may limit treatment for patients with potentially curable OEGEJC and can be adapted to include patients with a good performance status who are older than 75 years or have >10% pretreatment weight loss. However, the inclusion of patients with celiac nodal metastases or tumours >8 cm in length or >5 cm in width may be associated with poor outcomes.

Amiodarone disrupts cholesterol biosynthesis pathway and causes accumulation of circulating desmosterol by inhibiting 24-dehydrocholesterol reductase.

BACKGROUND: We have earlier reported that amiodarone, a potent and commonly used antiarrhythmic drug increases serum desmosterol, the last precursor of cholesterol, in 20 cardiac patients by an unknown mechanism. OBJECTIVE: Here, we extended our study to a large number of cardiac patients of heterogeneous diagnoses, evaluated the effects of combining amiodarone and statins (inhibitors of cholesterol synthesis at the rate-limiting step of hydroxy-methyl-glutaryl CoA reductase) on desmosterol levels and investigated the mechanism(s) by which amiodarone interferes with the metabolism of desmosterol using in vitro studies. METHODS AND RESULTS: We report in a clinical case-control setting of 236 cardiac patients (126 with and 110 without amiodarone treatment) that amiodarone medication is accompanied by a robust increase in serum desmosterol levels independently of gender, age, body mass index, cardiac and other diseases, and the use of statins. Lipid analyses in patient samples taken before and after initiation of amiodarone therapy showed a systematic increase of desmosterol upon drug administration, strongly arguing for a direct causal link between amiodarone and desmosterol accumulation. Mechanistically, we found that amiodarone resulted in desmosterol accumulation in cultured human cells and that the compound directly inhibited the 24-dehydrocholesterol reductase (DHCR24) enzyme activity. CONCLUSION: These novel findings demonstrate that amiodarone blocks the cholesterol synthesis pathway by inhibiting DHCR24, causing a robust accumulation of cellular desmosterol in cells and in the sera of amiodarone-treated patients. It is conceivable that the antiarrhythmic potential and side effects of amiodarone may in part result from inhibition of the cholesterol synthesis pathway.

Posttransplant Lymphoproliferative Disorder After Clinical Islet Transplantation: Report of the First Two Cases.

We report the first two cases of posttransplant lymphoproliferative disorder (PTLD) in recipients of islet transplants worldwide. First, a 44-year-old recipient of three islet infusions developed PTLD 80 months after his initial transplantation, presenting with abdominal pain and diffuse terminal ileum thickening on imaging. He was treated with surgical excision, reduction of immunosuppression, and rituximab. Seven months later, he developed central nervous system PTLD, presenting with vertigo and diplopia; immunosuppression was discontinued, resulting in graft loss, and he was given high-dose methotrexate and underwent consolidative autologous stem cell transplantation. He remains in remission 37 months after the initial diagnosis. Second, a 58-year-old female recipient of two islet infusions developed PTLD 24 months after initial islet infusion, presenting with pancytopenia secondary to extensive bone marrow involvement. Immunosuppression was discontinued, resulting in graft loss, and she received rituximab and chemotherapy, achieving complete remission. Both patients were monomorphic B cell PTLD subtype by histology and negative for Epstein-Barr virus in tissue or blood. These cases document the first occurrences of this rare complication in islet transplantation, likely secondary to prolonged, intensive immunosuppression, and highlight the varying clinical manifestations of PTLD. Further studies are needed to determine incidence rate and risk factors in islet transplantation.

Health care delivery for head-and-neck cancer patients in Alberta: a practice guideline.

BACKGROUND: The treatment of head-and-neck cancer is complex and requires the involvement of various health care professionals with a wide range of expertise. We describe the process of developing a practice guideline with recommendations about the organization and delivery of health care services for head-and-neck cancer patients in Alberta. METHODS: Outcomes of interest included composition of the health care team, qualification requirements for team members, cancer centre and team member volumes, infrastructure needs, and wait times. A search for existing practice guidelines and a systematic review of the literature addressing the organization and delivery of health care services for head-and-neck cancer patients were conducted. The search included the Standards and Guidelines Evidence (sage) directory of cancer guidelines and PubMed. RESULTS: One practice guideline was identified for adaptation. Three additional practice guidelines provided supplementary evidence to inform guideline recommendations. Members of the Alberta Provincial Head and Neck Tumour Team (consisting of various health professionals from across the province) provided expert feedback on the adapted recommendations through an online and in-person review process. Selected experts in head-and-neck cancer from outside the province participated in an external online review. SUMMARY: The recommendations outlined in this practice guideline are based on existing guidelines that have been modified to fit the Alberta context. Although specific to Alberta, the recommendations lend credence to similar published guidelines and could be considered for use by groups lacking the resources of appointed guideline panels. The recommendations are meant to be a guide rather than a fixed protocol. The implementation of this practice guideline will depend on many factors, including but not limited to availability of trained personnel, adequate funding of infrastructure, and collaboration with other associations of health care professionals in the province.

The phytochrome A specific signaling component PAT3 is a positive regulator of Arabidopsis photomorphogenesis.

Phytochrome A plays a major role in early seedling development by triggering the transition from etiolated growth to greening. Seedlings germinated under constant far-red (FR) light show a partially de-etiolated phenotype that is not seen in phyA mutants. This phytochrome A specific response was used to screen a population of T-DNA mutagenized Arabidopsis seedlings. One mutant line, pat3 (phytochrome A signal transduction3), which showed no inhibition of hypocotyl elongation under FR light conditions and no FR-induced killing response, contained a T-DNA insertion in a 609-bp ORF. The recessive mutation co-segregated with the T-DNA resistance marker and could be allelic to fhy1. A 2,248-bp genomic fragment of the PAT3 locus can complement the pat3 mutant phenotype. PAT3 transcript peaked 3 d after germination and was downregulated by light. PAT3 has no significant homology to any known protein and shows no preferential cellular localization. The protein can activate transcription in yeast when fused to the GAL4 DNA-binding domain. Our results show that PAT3 is a positive regulator of phytochrome A signal transduction.

Parturient-controlled epidural analgesia during labour: bupivacaine vs. ropivacaine.

In this randomised, controlled study, we compared the hourly dose requirement of ropivacaine 0.125% (group R, n = 16) with bupivacaine 0.125% (group B, n = 16) provided by demand-only (bolus 5 ml, lockout 10 min) parturient-controlled epidural analgesia during labour. The hourly dose requirement was comparable although group R had a lower successful to total demands ratio (p < 0.05). We also found that both groups were clinically indistinguishable in terms of pain relief and side-effects. No difference in maternal or fetal outcome was detected. We conclude that, at a concentration of 0.125%, ropivacaine and bupivacaine were equally effective when self-administered using this patient-controlled regimen.

Overexpression of Arabidopsis ESR1 induces initiation of shoot regeneration.

Functional screening of an Arabidopsis cDNA library enabled the identification of a novel cDNA, ESR1 (for Enhancer of Shoot Regeneration), that can confer cytokinin-independent shoot formation when overexpressed in Arabidopsis root explants. Neither callus induction nor root formation was affected by ESR1 overexpression. ESR1 encodes a putative transcription factor with an AP2/EREBP domain. Surprisingly, ESR1 overexpression also greatly increased the efficiency of shoot regeneration from root explants in the presence of cytokinin, with a shift in the optimal cytokinin concentration required for this process. The effects of ESR1 overexpression on shoot regeneration are synergistic with those of cytokinin. Overexpression of ESR1 cannot induce callus formation or root formation, suggesting that its effects are specific to shoot formation. In wild-type Arabidopsis plants, ESR1 expression was induced by cytokinin. ESR1 transcript levels also increased transiently during shoot regeneration from root explants, most probably in response to cytokinin in the shoot-inducing medium. This transient increase occurred after the acquisition of competence for regeneration and before shoot formation, which is consistent with the physiological effects of ESR1 overexpression. Our results suggest that ESR1 may regulate the induction of shoot regeneration after the acquisition of competence for organogenesis.

Reduced expression of alpha-tubulin genes in Arabidopsis thaliana specifically affects root growth and morphology, root hair development and root gravitropism.

Different alpha-tubulin cDNA sequences fused in an antisense orientation to a CaMV 35S promoter were introduced into Arabidopsis thaliana plants. Several independent transgenic lines that showed a moderate but clear reduction of alpha-tubulin gene expression (TUA6/AS lines) were obtained and phenotypically characterized. Although no apparent abnormalities were detected in the aerial parts of TUA6/AS plants, root development was severely affected. Cells in TUA6/AS root tips were found to contain aberrant microtubular structures, to expand abnormally and to be unable to undergo regular cell division. These cellular defects caused a dramatic radial expansion of the root tip and inhibited root elongation. In addition, TUA6/AS roots displayed ectopic formation of root hairs, root hair branching and a reduced ability to respond to gravitropic challenges. Our results contribute to an improved understanding of the different roles microtubules play during root development and demonstrate that reverse genetics is a powerful tool to analyze cytoskeletal functions during plant organogenesis.

LAF1, a MYB transcription activator for phytochrome A signaling.

The photoreceptor phytochrome (phy) A has a well-defined role in regulating gene expression in response to specific light signals. Here, we describe a new Arabidopsis mutant, laf1 (long after far-red light 1) that has an elongated hypocotyl specifically under far-red light. Gene expression studies showed that laf1 has reduced responsiveness to continuous far-red light but retains wild-type responses to other light wavelengths. As far-red light is only perceived by phyA, our results suggest that LAF1 is specifically involved in phyA signal transduction. Further analyses revealed that laf1 is affected in a subset of phyA-dependent responses and the phenotype is more severe at low far-red fluence rates. LAF1 encodes a nuclear protein with strong homology with the R2R3-MYB family of DNA-binding proteins. Experiments using yeast cells identified a transactivation domain in the C-terminal portion of the protein. LAF1 is constitutively targeted to the nucleus by signals in its N-terminal portion, and the full-length protein accumulates in distinct nuclear speckles. This accumulation in speckles is abolished by a point mutation in a lysine residue (K258R), which might serve as a modification site by a small ubiquitin-like protein (SUMO).

Inactivation of AtRac1 by abscisic acid is essential for stomatal closure.

Plant water homeostasis is maintained by the phytohormone abscisic acid (ABA), which triggers stomatal pore closure in response to drought stress. We identified the Arabidopsis small guanosine triphosphatase (GTPase) protein AtRac1 as a central component in the ABA-mediated stomatal closure process. ABA treatment induced inactivation of AtRac GTPases and disruption of the guard cell actin cytoskeleton. In contrast, in the ABA-insensitive mutant abi1-1, which is impaired in stomatal closure, neither AtRac inactivation nor actin cytoskeleton disruption was observed on ABA treatment. These observations indicate that AtRac1 inactivation is a limiting step in the ABA-signaling cascade leading to stomatal closure. Consistent with these findings, expression of a dominant-positive mutant of AtRac1 blocked the ABA-mediated effects on actin cytoskeleton and stomatal closure in wild-type plants, whereas expression of a dominant-negative AtRac1 mutant recapitulated the ABA effects in the absence of the hormone. Moreover, the dominant-negative form of AtRac1 could also restore stomatal closure in abi1-1. These results define AtRac1 as a central element for plant adaptation to drought.

ADF proteins are involved in the control of flowering and regulate F-actin organization, cell expansion, and organ growth in Arabidopsis.

Based mostly on the results of in vitro experiments, ADF (actin-depolymerizing factor) proteins are thought to be key modulators of the dynamic organization of the actin cytoskeleton. The few studies concerned with the in vivo function of ADF proteins that have been reported to date were performed almost exclusively using single-cell systems and have failed to produce consistent results. To investigate ADF functions in vivo and during the development of multicellular organs, we generated transgenic Arabidopsis plants that express a cDNA encoding an ADF protein (AtADF1) in the sense or the antisense orientation under the control of a strong constitutively active promoter. Selected lines with significantly altered levels of AtADF protein expression were characterized phenotypically. Overexpression of AtADF1 resulted in the disappearance of thick actin cables in different cell types, caused irregular cellular and tissue morphogenesis, and reduced the growth of cells and organs. In contrast, reduced AtADF expression promoted the formation of actin cables, resulted in a delay in flowering, and stimulated cell expansion as well as organ growth. These results are consistent with the molecular functions of ADF as predicted by in vitro studies, support the global roles of ADF proteins during the development of a multicellular organism, and demonstrate that these proteins are key regulators of F-actin organization, flowering, and cell and organ expansion in Arabidopsis.

Molecular identification and characterization of the Arabidopsis AtADF1, AtADFS and AtADF6 genes.

Actin depolymerizing factor (ADF) is a key regulator of the organization of the actin cytoskeleton during various cellular activities. We found that ADF genes in Arabidopsis form a large family consisting of at least nine members, four of which were cloned and sequenced in this study. Comparison of genomic and cDNA sequences showed that the AtADF1, AtADF5, and AtADF6 genes all contain two introns at conserved positions. Analysis of transgenic Arabidopsis plants carrying promoter-GUS fusion constructs revealed that AtADF1 and AtADF6 are expressed in the vascular tissues of all organs, whereas expression of AtADF5 is restricted to the root tip meristem. GFP-AtADFI, GFP-AtADF5, and GFP-AtADF6 fusion proteins were found to bind to actin filaments in vivo, and to reorganize the actin cytoskeleton when transiently expressed in plant cells.

Arabidopsis PLC1 is required for secondary responses to abscisic acid signals.

The role of inositol 1,4,5-trisphosphate (Ins[1,4,5]P3) in transducing the abscisic acid (ABA) signal during seed germination and in the stress responses of mature plants is poorly understood. We have considered the contributions of the phospholipase C1 (encoded by AtPLC1) and an Ins(1,4,5)P3 5-phosphatase (encoded by AtIP5PII) to ABA signaling by using a modified version of the glucocorticoid-inducible system to regulate transgene expression. In the presence of the dexamethasone (Dex) inducer, transgenic lines expressing the AtPLC1 antisense and AtIP5PII sense transgenes showed no inhibition of germination and growth by ABA, whereas in the absence of the inducer they were sensitive. In the presence of Dex, these lines accumulated lower Ins(1,4,5)P3 levels upon ABA treatment compared with that of the control transgenic lines. RNA gel blot analysis revealed a decrease in the induction of the ABA-responsive genes RD29a, KIN2, and RD22 but not COR47 in the Dex-induced transgenic plants. In transgenic lines expressing the inducible AtPLC1 sense transgene, an increase in AtPLC1 expression was not sufficient to activate the expression of ABA-responsive genes in vegetative tissues. In vitro experiments demonstrated the induced PLC1 expression when extracts were assayed in the presence of calcium, but no increase in Ins(1,4,5)P3 levels in vivo was detected, suggesting that the PLC1 enzyme was latent. Our results indicate that although an increase in PLC1 activity and increased Ins(1,4,5)P3 levels are necessary for maximal gene induction by ABA, overexpression of AtPLC1 itself is not sufficient to trigger the expression of ABA-responsive genes. We propose that AtPLC1 plays a role in secondary ABA responses.

A postgermination developmental arrest checkpoint is mediated by abscisic acid and requires the ABI5 transcription factor in Arabidopsis.

Seed dormancy is a trait of considerable adaptive significance because it maximizes seedling survival by preventing premature germination under unfavorable conditions. Understanding how seeds break dormancy and initiate growth is also of great agricultural and biotechnological interest. Abscisic acid (ABA) plays primary regulatory roles in the initiation and maintenance of seed dormancy. Here we report that the basic leucine zipper transcription factor ABI5 confers an enhanced response to exogenous ABA during germination, and seedling establishment, as well as subsequent vegetative growth. These responses correlate with total ABI5 levels. We show that ABI5 expression defines a narrow developmental window following germination, during which plants monitor the environmental osmotic status before initiating vegetative growth. ABI5 is necessary to maintain germinated embryos in a quiescent state thereby protecting plants from drought. As expected for a key player in ABA-triggered processes, ABI5 protein accumulation, phosphorylation, stability, and activity are highly regulated by ABA during germination and early seedling growth.

Chemical-regulated, site-specific DNA excision in transgenic plants.

We have developed a chemical-inducible, site-specific DNA excision system in transgenic Arabidopsis plants mediated by the Cre/loxP DNA recombination system. Expression of the Cre recombinase was tightly controlled by an estrogen receptor-based fusion transactivator XVE. Upon induction by beta-estradiol, sequences encoding the selectable marker, Cre, and XVE sandwiched by two loxP sites were excised from the Arabidopsis genome, leading to activation of the downstream GFP (green fluorescent protein) reporter gene. Genetic and molecular analyses indicated that the system is tightly controlled, showing high-efficiency inducible DNA excision in all 19 transgenic events tested with either single or multiple T-DNA insertions. The system provides a highly reliable method to generate marker-free transgenic plants after transformation through either organogenesis or somatic embryogenesis.

A plastidic ABC protein involved in intercompartmental communication of light signaling.

Plants perceive light via specialized photoreceptors of which the phytochromes (phyA-E), absorbing far-red (FR) and red light (R) are best understood. Several nuclear and cytoplasmic proteins have been characterized whose deficiencies lead to changes in light-dependent morphological responses and gene expression. However, no plastid protein has yet been identified to play a role in phytochrome signal transduction. We have isolated a new Arabidopsis mutant, laf (long after FR) 6, with reduced responsiveness preferentially toward continuous FR light. The disrupted gene in laf6 encodes a novel plant ATP-binding-cassette (atABC1) protein of 557 amino acids with high homology to ABC-like proteins from lower eukaryotes. In contrast to lower eukaryotic ABCs, however, atABC1 contains an N-terminal transit peptide, which targets it to chloroplasts. atABC1 deficiency in laf6 results in an accumulation of the chlorophyll precursor protoporphyrin IX and in attenuation of FR-regulated gene expression. The long hypocotyl phenotype of laf6 and the accumulation of protoporphyrin IX in the mutant can be recapitulated by treating wild-type (WT) seedlings with flumioxazin, a protoporphyrinogen IX oxidase (PPO) inhibitor. Moreover, protoporphyrin IX accumulation in flumioxazin-treated WT seedlings can be reduced by overexpression of atABC1. Consistent with the notion that ABC proteins are involved in transport, these observations suggest that functional atABC1 is required for the transport and correct distribution of protoporphyrin IX, which may act as a light-specific signaling factor involved in coordinating intercompartmental communication between plastids and the nucleus.

An alternative cytokinin biosynthesis pathway.

Studies of de novo cytokinin biosynthesis in isopentenyltransferase (ipt)-transformed Arabidopsis thaliana, involving in vivo deuterium labeling and mass spectrometry, showed that the biosynthetic rate of zeatinriboside-5'-monophosphate was around 66-fold higher than that of isopentenyladenosine-5'-monophosphate (iPMP), the proposed primary product of the Agrobacterium ipt. Double tracer analysis, using [(2)H(6)] isopentenyladenosine and deuterium oxide, provided evidence for an alternative, iPMP-independent, biosynthetic pathway for zeatin-type cytokinins, present in both ipt-expressing and wild-type Arabidopsis thaliana. Reduction of the biosynthetic flux in the alternative pathway by use of mevastatin, an inhibitor for 3-hydroxy-3-methylglutaryl CoA reductase, indicated a terpenoid origin for the side-chain precursor of the iPMP independent pathway.

Profilin plays a role in cell elongation, cell shape maintenance, and flowering in Arabidopsis.

Profilin (PFN) is an ubiquitous, low-M(r), actin-binding protein involved in the organization of the cytoskeleton of eukaryotes including higher plants. PFNs are encoded by a multigene family in Arabidopsis. We have analyzed in vivo functions of Arabidopsis PFN by generating transgenic plants carrying a 35S-PFN-1 or 35S-antisense PFN-1 transgene. Etiolated seedlings underexpressing PFN (PFN-U) displayed an overall dwarf phenotype with short hypocotyls whose lengths were 20% to 25% that of wild type (WT) at low temperatures. Light-grown PFN-U plants were smaller in stature and flowered early. Compared with equivalent cells in WT, most cells in PFN-U hypocotyls and roots were shorter, but more isodiametric, and microscopic observations of etiolated PFN-U hypocotyls revealed a rough epidermal surface. In contrast, light-grown seedlings overexpressing PFN had longer roots and root hair although etiolated seedlings overexpressing PFN were either the same size or slightly longer than WT seedlings. Transgenic seedlings harboring a PFN-1-GUS transgene directed expression in root and root hair and in a ring of cells at the elongating zone of the root tip. As the seedlings matured PFN-1-GUS was mainly expressed in the vascular bundles of cotyledons and leaves. Our results show that Arabidopsis PFNs play a role in cell elongation, cell shape maintenance, polarized growth of root hair, and unexpectedly, in determination of flowering time.

Arabidopsis NAC1 transduces auxin signal downstream of TIR1 to promote lateral root development.

Auxin plays a key role in lateral root formation, but the signaling pathway for this process is poorly understood. We show here that NAC1, a new member of the NAC family, is induced by auxin and mediates auxin signaling to promote lateral root development. NAC1 is a transcription activator consisting of an N-terminal conserved NAC-domain that binds to DNA and a C-terminal activation domain. This factor activates the expression of two downstream auxin-responsive genes, DBP and AIR3. Transgenic plants expressing sense or antisense NAC1 cDNA show an increase or reduction of lateral roots, respectively. Finally, TIR1-induced lateral root development is blocked by expression of antisense NAC1 cDNA, and NAC1 overexpression can restore lateral root formation in the auxin-response mutant tir1, indicating that NAC1 acts downstream of TIR1.