Dormancy and germination of olive embryos as affected by temperature

Olive seeds do not germinate promptly when placed under favourable conditions, which is a problem in raising young plants for breeding or experimental purposes. In a series of experiments an investigation of the role of temperature in the germination of olive embryos was conducted. Naked, unchilled olive embryos ( Olea europaea L. cv. Chalkidikis), cultured in vitro at 20°C, had a germination capacity of 73%, whereas that of embryos which had previously been chilled at 10°C for 2 or more weeks reached 96%. Intact seeds did not germinate at 20°C unless they had previously been subjected to 10°C for 3 or 4 weeks. Embryos chilled while in the intact seed and excised just before transfer to 20°C, reacted in a similar way to naked embryos, but reached their maximum germination capacity after 4 weeks at 10°C. Under constant temperature conditions the highest germination percentage of embryos was observed at 10 and 15°C and the highest germination rate at 15°C, while a moderate capacity and rate of germination occurred at 20°C, and a very low percentage and rate at 25 and 30°C. Prechilling at 10°C did not affect germination at 15°C, but improved the percentage and the rate of germination at 20, 25 and 30°C. The germination percentages of embryos chilled for 1 or 2 weeks at 10°C and then transferred to 25°C were lower than those of similarly chilled embryos transferred to 20°C. The chilling effect could not be reversed at 25°C when the embryos had been chilled for 3 or more weeks. The results show that olive seeds exhibit a state of dormancy that is caused by factors residing partly in the endosperm and partly within the embryo.     

Intracoronary and systemic release of the atrial natriuretic factor and cyclic-guanosine monophosphate during coronary angioplasty

Summary This study was undertaken to investigate intracoronary production and systemic release of the atrial natriuretic factor (ANF) and cyclic-guanosine monophosphate (c-GMP) during coronary angioplasty (PTCA). three coronary blood samples were collected, through a balloon catheter, from the area distal to the lesion: before balloon inflation, at maximum inflation and 5 min later. Four additional venous samples were collected: before PTCA, and 5 min, 2 h and 24 h after the procedure. Local intracoronary c-GMP production increased from the baseline level of 7.5±0.9 pmol/ml to 11.1±1.3 pmol/ml at maximum balloon inflation (p<0.01) and decreased 5 min later to 9.5 ±1.0 pmol/ml (p=NS). In contrast, intracoronary ANF production failed to show any significant change at any time during the procedure. Peripheral venous ANF levels increased from 79.1±11.1 pmol/ml to 99.9±16.6 pmol/ml 5 min after balloon inflation (p<0.05) and gradually decreased 2 h (91.9±13.6 pmol/ml) and 24 h (85.6±10.4 pmol/ml) after the procedure. Similarly, peripheral venous c-GMP levels increased from 11.3±1.7 pmol/ml before PTCA to 14.9±1.9 pmol/ml 5 min after balloon inflation (p<0.05), and then gradually decreased 2 h (10.8±1.4 pmol/ml) and 24 h (8.2±1.4 pmol/ml) after the procedure (p<0.01 and <0.0001 compared to the peak value, respectively). In conclusion, acute vessel occlusion and distension during balloon inflation stimulates intracoronary c-GMP production without affecting ANF release.     

Halonium ion-induced biosynthesis of chlorinated marine metabolites

Bromoperoxidases do not directly oxidize the chloride ion; nevertheless, in the presence of bromide ions, chloride ions and hydrogen peroxide, bromoperoxidases react with alkenes and alkynes to produce bromochloroderivatives. This same reaction is catalysed when seawater is the source of chloride and bromide ions. This suggests that bromonium ion-induced biosynthesis of chlorinated metabolites occurs in marine environments. The role of iodonium ions in the biosynthesis of chlorinated metabolites is also discussed.     

Characterization of a photosystem II reaction center complex isolated by exposure of PSII membranes to a non-ionic detergent and high concentrations of NaCl

A highly resolved PSII reaction center complex has been prepared by exposure of PSII membranes to the detergent octylglucopyranoside at elevated ionic strengths; oxygen evolution activity is about 1,000 moles O₂/hr/mg Chl in the presence of CaCl₂. A Mn quantitation and a kinetic study of Z, the donor to P₆₈₀, reveals that on a Chl basis this new preparation shows an almost four-fold enrichment in Mn and the electron transport components of PSII.Abbreviations BZ benzidine - Chl chlorophyll - DCBQ 2,5-dichloro-p-benzoquinone - EPR electron paramagnetic resonance - LHC light harvesting complex - OGP 1-O-n-octyl-b-D-glucopyranoside - PSII Photosystem II - R.C.C. reaction center complex - Tris 2-amino-2-(hydroxymethyl)-1-3-propanediol. Dedicated to the memory of Warren Butler, whose research provided new insights and ideas about the structure and function of PSII.     

Defining priorities for improving end-of-life care in Canada

Background

High-quality end-of-life care should be the right of every Canadian. The objective of this study was to identify aspects of end-of-life care that are high in priority as targets for improvement using feedback elicited from patients and their families.

Methods

We conducted a multicentre, cross-sectional survey involving patients with advanced, life-limiting illnesses and their family caregivers. We administered the Canadian Health Care Evaluation Project (CANHELP) questionnaire along with a global rating question to measure satisfaction with end-of-life care. We derived the relative importance of individual questions on the CANHELP questionnaire from their association with a global rating of satisfaction, as determined using Pearson correlation coefficients. To determine high-priority issues, we identified questions that had scores indicating high importance and low satisfaction.

Results

We approached 471 patients and 255 family members, of whom 363 patients and 193 family members participated, with response rates of 77% for patients and 76% for families. From the perspective of patients, high-priority areas needing improvement were related to feelings of peace, to assessment and treatment of emotional problems, to physician availability and to satisfaction that the physician took a personal interest in them, communicated clearly and consistently, and listened. From the perspective of family members, similar areas were identified as high in priority, along with the additional areas of timely information about the patient’s condition and discussions with the doctor about final location of care and use of end-of-life technology.

Interpretation

End-of-life care in Canada may be improved for patients and their families by providing better psychological and spiritual support, better planning of care and enhanced relationships with physicians, especially in aspects related to communication and decision-making.Although a “quality death” is an espoused right of Canadians,¹ for many dying patients and their families, it is not achieved. Recent reviews and observational studies describe considerable dissatisfaction with end-of-life care, indicating that there are still opportunities for improvement.^2–5Ideally, initiatives aimed at improving end-of-life care would be informed by the experiences and expectations of patients and their family members. However, such efforts are often hampered by inadequate definitions of quality of care and by suboptimal tools for measurement.^6–8 In a recent, large cross-sectional survey, the Canadian Researchers at the End of Life Network defined what matters most to seriously ill patients as they approach the end of life.⁹ Both patients and their family members reported that it was extremely important that they have trust and confidence in the physicians caring for them or their loved ones.⁹ Avoidance of unwanted life-support measures, effective communication, continuity of care, and feelings of life completion were also rated as highly important.⁹ We used these comprehensive ratings of importance to develop and validate a novel questionnaire to measure satisfaction with end-of-life care.¹⁰ Using this questionnaire, we formally evaluated the care received at the end of life in several Canadian centres.By targeting initiatives for change at gaps in quality, we can address the highest priorities for improving end-of-life care in Canada. Our objective was to identify high-priority areas for improvement in the care of patients with advanced, life-limiting diseases and in the perceived quality of that care by their families. We identified these areas by focusing on care-related issues that had been rated as important by patients and their family members but were rated low on the questionnaire measuring satisfaction with end-of-life care.     

Genetic and pharmacologic inhibition of β-catenin targets imatinib-resistant leukemia stem cells in CML

A key characteristic of hematopoietic stem cells (HSCs) is the ability to self-renew. Genetic deletion of β-catenin during fetal HSC development leads to impairment of self-renewal while β-catenin is dispensable in fully developed adult HSCs. Whether β-catenin is required for maintenance of fully developed CML leukemia stem cells (LSCs) is unknown. Here, we use a conditional mouse model to show that deletion of β-catenin after CML initiation does not lead to a significant increase in survival. However, deletion of β-catenin synergizes with imatinib (IM) to delay disease recurrence after imatinib discontinuation and to abrogate CML stem cells. These effects can be mimicked by pharmacologic inhibition of β-catenin via modulation of prostaglandin signaling. Treatment with the cyclooxygenase inhibitor indomethacin reduces β-catenin levels and leads to a reduction in LSCs. In conclusion, inhibiting β-catenin by genetic inactivation or pharmacologic modulation is an effective combination therapy with imatinib and targets CML stem cells.     

Angiopoietin-2 Primes Infection-Induced Preterm Delivery

Current knowledge on the participation of angiopoietin-2 (Ang-2) in the inflammatory process and on the importance of bacterial endotoxins (LPS) in the induction of preterm delivery (PTD) led us to investigate the role of Ang-2/LPS interplay in the pathogenesis of PTD. At a first stage, Ang-2 was measured at the end of the first trimester of pregnancy in the serum of 50 women who delivered prematurely; of 88 women well-matched for age and parity who delivered full-term; and of 20 non-pregnant healthy women. Ang-2 was greater in pregnant than in non-pregnant women. The time until delivery was shorter among those with Ang-2 greater than 4 ng/ml (odds ratio for delivery until week 34; p: 0.040). To further investigate the role of Ang-2 for PTD, an experimental model of PTD induced by the intraperitoneal injection of LPS in mice was used. Ang-2 was administered intraperitoneally before LPS on day 14 of pregnancy. When Ang-2 was administered before the LPS diluent, all mice delivered full-term. However, administration of Ang-2 prior LPS accelerated further the time until delivery. Sacrifice experiments showed that the effect of Ang-2 was accompanied by decrease of the penetration of Evans Blue in the embryos and by increase of its penetration in maternal tissues. In parallel, the concentration of tumour necrosis factor-alpha in the maternal circulation, in fetal tissues and in the placentas was significantly decreased. Results indicate that Ang-2 accelerated the phenomena of PTD induced by LPS. This is related with deprivation of fetal perfusion.