ABSTRACT
The conservation of the genetic resources of old trees is crucial to their ecological role but is extremely difficult, especially for oak species (Quercus spp.) displaying recalcitrance in seed and vegetative propagation methods. Our study aimed to assess the regenerative potential of Quercus robur trees of different ages (up to 800 years) during micropropagation. We also aimed to determine how in vitro conditions can influence in vitro regeneration responses. Lignified branches collected from 67 selected trees were cultivated ex vitro in culture pots at 25 °C to obtain epicormic shoots (explant sources). The explants were cultivated on an agar medium supplemented with 0.8 mg L-1 6-benzylaminopurine (BAP) for at least 21 months. In a second experiment, two different shoot multiplication conditions (temporary immersion-RITA® bioreactor and agar medium) and two culture medium formulations (Woody Plant Medium and modified Quoirin and Lepoivre medium) were tested. The results showed that the mean length of the epicormic shoots obtained in a pot culture was a function of donor age and was similar among the group of younger trees (ca. 20-200 years), and varied between older trees (ca. 300-800 years). The efficiency of in vitro shoot multiplication strictly depended on the genotype. A sustainable in vitro culture (defined as survival after 6 months) was only possible for half of the tested old donor trees, even when they survived the first month of in vitro growth. A continuous monthly increase in the number of in vitro cultured shoots was reported in younger oaks and in some old oaks. We found a significant effect of the culture system and the macro- and micronutrient composition on in vitro shoot growth. This is the first report demonstrating that the in vitro culture can be successfully applied to the propagation of even 800-year-old pedunculate oak trees.
ABSTRACT
BACKGROUND: The number of patients with implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy and defibrillator (CRT-D) is growing. This results in high workloads for centers performing standard controls (SC) of these systems. Medtronic CareLink Express® (MCLE) is a solution enabling remote controls (RC) of implantable devices. In cases of detecting arrhythmias or device malfunctioning, it automatically generates alarms transmitted to the controlling physician. The objective of the study was to evaluate the effectiveness of alarms generated by MCLE in identification of patients that require clinically significant intervention during SC. METHODS: A total of 119 patients (age 64 ± 14, 17 women) implanted with ICD/CRT-D were included in the trial. Device reprogramming or pharmacological treatment modifications during SC were as-sessed as significant if they were required for optimal clinical management of the patient (effectiveness of antiarrhythmic and resynchronization therapy, also patient safety). Analysis of generated alarms was then performed to assess the effectiveness (sensitivity and specificity) of MCLE in identifying patients that require changes in therapy. RESULTS: Data from 129 transmissions and 129 subsequent SCs were analyzed. 179 alarms were recorded during 96 (74%) transmissions. A total of 333 program changes of implanted devices took place during 107 (83%) SCs. Device reprogramming was considered clinically significant in 27 cases Additionaly, 13 pharmacological treatment modifications were performed. Sensitivity and specificity of alarms generated by MCLE with regards to identification of patients requiring clinically significant intervention was 87% and 31%, respectively. Finally, a statistically significant difference was observed in the number of clinically significant interventions among patients with and without MCLE alarms (33 [86.8%] vs. 5 [13.2%], p = 0.037). CONCLUSIONS: Medtronic CareLink Express® is an RC system enabling high-sensitivity supervision of patients with cardiac.