Current and future potential distributions of three Dracaena Vand. ex L. species under two contrasting climate change scenarios in Africa.

Forest undergrowth plants are tightly connected with the shady and humid conditions that occur under the canopy of tropical forests. However, projected climatic changes, such as decreasing precipitation and increasing temperature, negatively affect understory environments by promoting light-demanding and drought-tolerant species. Therefore, we aimed to quantify the influence of climate change on the spatial distribution of three selected forest undergrowth plants, Dracaena Vand. ex L. species, D. afromontana Mildbr., D. camerooniana Baker, and D. surculosa Lindl., simultaneously creating the most comprehensive location database for these species to date. A total of 1,223 herbarium records originating from tropical Africa and derived from 93 herbarium collections worldwide have been gathered, validated, and entered into a database. Species-specific Maxent species distribution models (SDMs) based on 11 bioclimatic variables from the WorldClim database were developed for the species. HadGEM2-ES projections of bioclimatic variables in two contrasting representative concentration pathways (RCPs), RCP2.6 and RCP8.5, were used to quantify the changes in future potential species distribution. D. afromontana is mostly sensitive to temperature in the wettest month, and its potential geographical range is predicted to decrease (up to -63.7% at RCP8.5). Optimum conditions for D. camerooniana are low diurnal temperature range (6-8°C) and precipitation in the wettest season exceeding 750 mm. The extent of this species will also decrease, but not as drastically as that of D. afromontana. D. surculosa prefers high precipitation in the coldest months. Its potential habitat area is predicted to increase in the future and to expand toward the east. This study developed SDMs and estimated current and future (year 2050) potential distributions of the forest undergrowth Dracaena species. D. afromontana, naturally associated with mountainous plant communities, was the most sensitive to predicted climate warming. In contrast, D. surculosa was predicted to extend its geographical range, regardless of the climate change scenario.

Dataset and GIS toolbox for modeling potential tree belt functions.

The dataset and toolbox presented in this article are related to the research article entitled "Modeling potential tree belt functions in rural landscapes using a new GIS tool" (Nowak and Pedziwiatr, 2008) [1]. The dataset (spatially referenced) is used as input for all the five analysis modules described in the related article. The dataset contains vector and raster data, which cover north-west part of the Gen. Dezydery Chlapowski Landscape Park in Poland. Moreover, the present work shows the result (a vector layer) of using the TBM toolbox within ArcGIS (ESRI) software. The Tree Belt Modeling (TBM toolbox) code and internal structure can be fully accessed, and are available for further modification and incorporation of tools. The toolbox is available for download as supplementary material to this online article.

Modeling potential tree belt functions in rural landscapes using a new GIS tool.

The increasing human pressure on the environment requires effective protection activities. One way to stop the degradation of natural resources is the presence of woody vegetation networks, mainly linear in character, called linear woody features, greenways or tree belts. These objects, thanks to the many natural and economic functions they serve, enable the realization of sustainable development policy. To properly design a greenway network, the natural conditions and degree of environmental degradation in a given area must first be evaluated. Based on these data, it is possible to determine appropriate afforestation needs. To evaluate the ability of a given area to meet the requirements of greenway functions, we propose a new computer modeling system - a tree belt modeling (TBM). TBM defines the availability of tree belt functions in the planned network and is one of preparation stages in the design of an optimal greenway structure. In this work, to analyze the studied area potential, application of a cadastral dataset was proposed. Thanks to this approach, the obtained results may be related to specific plot borders, which is optimal for greenway construction. To automatize the process of analysis, the TBM was implemented into an ArcGIS toolbox. The result of using this toolbox is a tree belt functions geodatabase. This database contains information about the available functions in the analyzed lines that are potential sites for afforestation. This solution, both at the methodological and technological levels, may significantly increase the effectiveness of greenway planning and thus contribute to more effective activities for sustainable development.

Robotic stereotactic body radiation therapy for liver-limited malignant tumors.

INTRODUCTION: Stereotactic body radiotherapy (SBRT) is rapidly gaining favor as a new treatment modality for malignant liver tumors. Most of the studies have recruited patients with disseminated disease originating from the liver. This study focuses on disease limited to the liver. AIM: To perform a retrospective analysis of all patients with liver tumors treated by robotic stereotactic body radiation therapy in a single center. MATERIAL AND METHODS: The study included 13 patients with 22 lesions. The inclusion criteria were: patients with 1-4 inoperable liver lesions and absence of any extrahepatic disease. All but 3 patients received 3 fractions delivered by the Cyberknife system of a total of 45 grey (Gy). The other 3 patients received 30 Gy. RESULTS: The median follow-up time was 10.8 months (range: 7-16). The median dose was 41.5 Gy (range: 30-45). One lesion regressed (8%). In 5 patients, the disease was locally stabilized (38%), and in 7 other patients progression occurred (54%). Twelve patients (92%) are still alive, and 1 patient (8%) died. In 1 patient a new cancer (leukemia) was diagnosed. CONCLUSIONS: The SBRT is well tolerated and effective for local control of most liver malignant tumors. It appears that SBRT is best suited for those patients in whom systemic recurrence can be controlled by chemotherapy. Further studies are mandatory to elucidate these effects on tumors of varying histology and to elaborate upon criteria used to select patients who can benefit most from this treatment.

Spinal cord ependymoma in children--results of postoperative radiotherapy.

PURPOSE: A retrospective study was performed to evaluate the results of postoperative radiation therapy of spinal cord ependymoma in children. METHODS AND MATERIALS: Between 1984 and 2005, 28 children with spinal cord ependymoma were treated with radiotherapy, after surgery and in three cases after chemotherapy as well. Median age at diagnosis was 13.3 years (range from 4.7 to 16.2 years). Ependymoma myxopapillare was identified in 13, ependymoma in 12 and anaplastic ependymoma in 3 cases. RESULTS: With a median follow-up of 8.7 years (range from 3 to 25 years) 22 patients were alive. The overall survival rate of 2, 5 and 10 years was 93%, 85% and 77% respectively, whereas progression free survival rate was 82%, 74% and 74% respectively. Patients with myxopapillary ependymoma had significantly better 5-year overall survival rate 100% than those with other histopathological types 60% (p=0.016). There were 2 relapse incidences observed among 13 patients with myxopapillary ependymoma, both underwent repeated surgery and reirradiation. In the group of 20 patients with gross total resection the overall 5-year survival rate was 100% in comparison with 62.5% with partial surgery, but it did not achieve statistical significance. CONCLUSIONS: The histological type of ependymoma myxopapillary was a statistical significant favourable prognostic factor. The gross total resection with adjuvant radiotherapy allows obtaining a high total survival rate.

Reirradiation of relapsed brain tumors in children.

AIM: The aim of this study was to evaluate toxicity and response to fractionated reirradiation (FR) of relapsed primary brain tumors in children. BACKGROUND: The treatment options for recurrent brain tumors in children previously irradiated are limited. Reirradiation is performed with fear due to the cumulative late CNS toxicity and the lack of a significant chance of cure. MATERIALS AND METHODS: Between 2008 and 2009, eight children with a median age of 14.5 years with a diagnosis of a recurrent brain tumor underwent reirradiation. Initially, all patients were treated with surgery, chemotherapy and radiotherapy. The median time to the first recurrence after the initial treatment was 19.5 months. Intervals between radiotherapy courses were in the range of 5-51 mos. All retreatments were carried out with 3D image-based conformal methods. The total prescription dose was 40 Gy in a fraction of 5 × 2 Gy/week. The total cumulative dose ranged from 65 to 95 Gy (median: 75 Gy). The median cumulative biologically effective dose was 144 Gy (range: 126-181 Gy). RESULTS: The median overall survival and progression free survival measured from the beginning of reirradiation was 17.5 and 6.5 months, respectively. During the first evaluation, four patients showed a complete or partial response, two did not respond radiologically. Two children were progressive at the time of reirradiation. Among children with progression that occurred during the first year after reirradiation, only two progressed in the treatment area. The repeated irradiation was well tolerated by all patients. No late complications have been observed. CONCLUSION: In the absence of other treatment possibilities, the fractionated reirradiation with highly conformal three-dimensional planning could be a therapeutic choice in case of recurrent brain tumors in children. The control of craniospinal dissemination remains to be the main problem.

Craniospinal radiotherapy in children: Electron- or photon-based technique of spinal irradiation.

BACKGROUND: The prone position and electron-based technique for craniospinal irradiation (CSI) have been standard in our department for many years. But this immobilization is difficult for the anaesthesiologist to gain airway access. The increasing number of children treated under anaesthesia led us to reconsider our technique. AIM: The purpose of this study is to report our new photon-based technique for CSI which could be applied in both the supine and the prone position and to compare this technique with our electron-based technique. MATERIALS AND METHODS: Between November 2007 and May 2008, 11 children with brain tumours were treated in the prone position with CSI. For 9 patients two treatment plans were created: the first one using photons and the second one using electron beams for spinal irradiation. We prepared seven 3D-conformal photon plans and four forward planned segmented field plans. We compared 20 treatment plans in terms of target dose homogeneity and sparing of organs at risk. RESULTS: In segmented field plans better dose homogeneity in the thecal sac volume was achieved than in electron-based plans. Regarding doses in organs at risk, in photon-based plans we obtained a lower dose in the thyroid but a higher one in the heart and liver. CONCLUSIONS: Our technique can be applied in both the supine and prone position and it seems to be more feasible and precise than the electron technique. However, more homogeneous target coverage and higher precision of dose delivery for photons are obtained at the cost of slightly higher doses to the heart and liver.

Evaluation of quality of life in long-term survivors of paediatric brain stem tumors, treated with radiotherapy.

The quality of life in long-term survivors of paediatric brain stem tumors, treated with radiotherapy is evaluated. They suffer predominantly from pre-treatment neurological impairments, which seriously influence their quality of life. The most often observed treatment sequelae are pituitary insufficiency and hearing loss.