Basin-Scale Control on the Phytoplankton Biomass in Lake Victoria, Africa

The relative bio-optical variability within Lake Victoria was analyzed through the spatio-temporal decomposition of a 1997–2004 dataset of remotely-sensed reflectance ratios in the visible spectral range. Results show a regular seasonal pattern with a phase shift (around 2 months) between the south and north parts of the lake. Interannual trends suggested a teleconnection between the lake dynamics and El-Niño phenomena. Both seasonal and interannual patterns were associated to conditions of light limitation for phytoplankton growth and basin-scale hydrodynamics on phytoplankton access to light. Phytoplankton blooms developed during the periods of lake surface warming and water column stability. The temporal shift apparent in the bio-optical seasonal cycles was related to the differential cooling of the lake surface by southeastern monsoon winds. North-south differences in the exposure to trade winds are supported by the orography of the Eastern Great Rift Valley. The result is that surface layer warming begins in the northern part of the lake while the formation of cool and dense water continues in the southern part. The resulting buoyancy field is sufficient to induce a lake-wide convective circulation and the tilting of the isotherms along the north-south axis. Once surface warming spreads over the whole lake, the phytoplankton bloom dynamics are subjected to the internal seiche derived from the relaxation of thermocline tilting. In 1997–98, El-Niño phenomenon weakened the monsoon wind flow which led to an increase in water column stability and a higher phytoplankton optical signal throughout the lake. This suggests that phytoplankton response to expected climate scenarios will be opposite to that proposed for nutrient-limited great lakes. The present analysis of remotely-sensed bio-optical properties in combination with environmental data provides a novel basin-scale framework for research and management strategies in Lake Victoria

Integrin inhibitor cilengitide for the treatment of glioblastoma: a brief overview of current clinical results.

Glioblastoma is the most frequent primary malignant brain tumor in adults. Postoperative radiotherapy (RT) with concomitant and adjuvant chemotherapy with temozolomide is the standard treatment, however the prognosis remains poor with a median survival in the range of 12-15 months. In recent years, several targeted agents have been developed as potential inhibitors of molecular genetic and signal transduction pathways involved in gliomatogenesis, including those of vascular endothelial growth factor and its receptor, epidermal growth factor receptor, integrin, and mammalian target of rapamycin. The integrins are a family of transmembrane glycoprotein receptors that mediate cell matrix and cell-cell interactions, and are widely expressed in glioma cells and tumor vasculature. The critical role of integrins in angiogenesis, cell invasion and migration make them an attractive target for anticancer therapy. Inhibitory peptides and monoclonal antibodies to integrins are currently being investigated in clinical trials in patients with solid tumors, such as colorectal cancer, renal cell carcinoma, and melanoma. Cilengitide, a cyclized Arg-Gly-Glu(RGD)-containing pentapeptide that selectively blocks activation of the αvβ3 and αvβ5 integrins has shown encouraging activity in patients with glioblastoma as single agent, and in association with standard RT and temozolomide. In this review, we provide a brief overview of the preclinical experience and current clinical results of cilengitide therapy in patients with recurrent or newly diagnosed glioblastoma

Integrin inhibitor cilengitide for the treatment of glioblastoma: A brief overview of current clinical results

Glioblastoma is the most frequent primary malignant brain tumor in adults. Postoperative radiotherapy (RT) with concomitant and adjuvant chemotherapy with temozolomide is the standard treatment, however the prognosis remains poor with a median survival in the range of 12-15 months. In recent years, several targeted agents have been developed as potential inhibitors of molecular genetic and signal transduction pathways involved in gliomatogenesis, including those of vascular endothelial growth factor and its receptor, epidermal growth factor receptor, integrin, and mammalian target of rapamycin. The integrins are a family of transmembrane glycoprotein receptors that mediate cell matrix and cell-cell interactions, and are widely expressed in glioma cells and tumor vasculature. The critical role of integrins in angiogenesis, cell invasion and migration make them an attractive target for anticancer therapy. Inhibitory peptides and monoclonal antibodies to integrins are currently being investigated in clinical trials in patients with solid tumors, such as colorectal cancer, renal cell carcinoma, and melanoma. Cilengitide, a cyclized Arg-Gly-Glu(RGD)- containing pentapeptide that selectively blocks activation of the αvβ3 and αvβ5 integrins has shown encouraging activity in patients with glioblastoma as single agent, and in association with standard RT and temozolomide. In this review, we provide a brief overview of the preclinical experience and current clinical results of cilengitide therapy in patients with recurrent or newly diagnosed glioblastoma

Chemoradiation for glioblastoma

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. Until recently, the standard of care consisted of maximal surgical resection followed by external beam radiotherapy (RT). Several randomized trials conducted over the past 30 years have failed to show a significant survival advantage for patients treated with BCNU or PCV chemotherapy. The randomized EORTC 26981/22981-NCIC trial has clearly demonstrated that the addition of the methylating agent temozolomide (TMZ) to RT followed by 6 monthly cycles of TMZ provides significant survival benefit with minimal additional toxicity in patients with GBM. A recent analysis of the trial revealed longer survival in patients with GBM which exhibited the methylation of the promoter region of the O (6)-methylguanine DNA methyltransferase (MGMT) gene. In patients with unfavourable prognostic factors, such as older age and poor performance status, abbreviated courses of RT in association with TMZ may be employed as an alternative to more aggressive treatments. Identification of many molecular genetic and signal transduction pathways involved in gliomatogenesis have yielded to the development of several targeted drugs, including epidermal growth factor receptor (EGFR) tyrosin kinase inhibitors, antiangiogenic agents, and integrin inhibitors, that are currently tested in combination with TMZ and RT. This review summarizes the results of chemoradiation for GBM and the development of new strategies under evaluation to increase the efficacy of treatments. © 2010 Bentham Science Publishers Ltd

Fractionated stereotactic reirradiation and concurrent temozolomide in patients with recurrent glioblastoma

The aim of this paper is to evaluate the efficacy of fractionated stereotactic radiotherapy (FSRT) and concomitant temozolomide (TMZ) as a salvage treatment option in patients with recurrent glioblastoma (GBM). Between May 2006 and December 2009, 36 patients with recurrent GBM received FSRT plus concomitant TMZ at University of Rome La Sapienza, Sant' Andrea Hospital. All patients had Karnofsky performance score ≥60 and were previously treated with standard conformal radiotherapy (RT) (60 Gy) with concomitant and adjuvant TMZ for 6-12 cycles. The median time interval between primary RT and reirradiation was 14 months. At the time of recurrence, all patients received FSRT plus concomitant daily TMZ at the dose of 75 mg/m2, given 7 days per week from the first day of RT. Radiation dose was 37.5 Gy delivered in 15 fractions over 3 weeks. Median overall survival after FSRT was 9.7 months, and the 6- and 12-month survival rates were 84 and 33%, respectively. The median progression-free survival (PFS) was 5 months, and 6- and 12-month PFS rates were 42 and 8%, respectively. In univariate analysis, KPS (P = 0.04), the interval between primary RT and reirradiation (P = 0.02), and O6-methylguanine-DNA- methyltransferase (MGMT) methylation status at the time of diagnosis (P = 0.009) had an effect on survival; however, in multivariate analysis, only MGMT methylation was statistically significant (P = 0.03). In general, FSRT was well tolerated and the treatment was completed in all patients. Neurological deterioration due to radiation-induced necrosis occurred in three patients (8%). FSRT plus concomitant TMZ is a feasible treatment option associated with survival benefits and low risk of complications in selected patients with recurrent GBM. The potential advantages of combined chemoradiation schedules in patients with recurrent GBM need to be explored in future studies. © 2010 Springer Science+Business Media, LLC

Short-term radiotherapy followed by adjuvant chemotherapy in poor-prognosis patients with glioblastoma

Objectives. The optimal treatment for patients with glioblastoma with unfavorable prognostic factors, such as old age and low performance status, remains controversial. We conducted a prospective study to assess the effect of temozolomide and short-course radiation versus short-course radiation alone in the treatment of poorprognosis patients with newly diagnosed glioblastoma. Patients andmethods. Forty-five patients with a newly diagnosed glioblastoma, older than 70 years or aged 50-70 years and with a Karnofsky performance score ≤70 were enrolled in this prospective study. Twenty-three patients were treated with an abbreviated course of radiotherapy (30 Gy in 6 fractions over 2 weeks) and 22 patients with the same radiotherapy schedule plus adjuvant temozolomide at the dose of 150-200 mg/m2 for 5 days every 28-day cycle. The primary end pointwas overall survival. Secondary end points included progression-free survival and toxicity. Results. Median overall survival was 7.3 months in the radiotherapy group and 9.4 months in the radiotherapy plus temozolomide group (P = 0.003), with respective 6-month overall survivals of 78% and 95%, respectively. Median progression-free survival was 4.4 months in the radiotherapy group and 5.5 months in the radiotherapy plus temozolomide group (P = 0.01), and respective 6-month progression-free survival rates were 22% and 45%. In multivariate analysis, Karnofsky performance score was the only significant independent predictive factor of survival (P = 0.03). Adverse effects of radiotherapy were mainly represented by neurotoxicity (24%), which resolved inmost cases with the use of steroids. Grade 3-4 hematologic toxicity occurred in 36% of patients treated with temozolomide. Conclusions. The addition of temozolomide to short-term radiotherapy resulted in a statistically significant survival benefit withminimal additional toxicity in poor-prognosis patients with newly diagnosed glioblastoma. Future studies need to define the best combined regimens of radiotherapy and temozolomide on survival and quality of life in this subgroup of patients. Free full text available at www.tumorionline.it

Short-term radiotherapy followed by adjuvant chemotherapy in poor-prognosis patients with glioblastoma

Objectives. The optimal treatment for patients with glioblastoma with unfavorable prognostic factors, such as old age and low performance status, remains controversial. We conducted a prospective study to assess the effect of temozolomide and short-course radiation versus short-course radiation alone in the treatment of poorprognosis patients with newly diagnosed glioblastoma. Patients andmethods. Forty-five patients with a newly diagnosed glioblastoma, older than 70 years or aged 50-70 years and with a Karnofsky performance score ≤70 were enrolled in this prospective study. Twenty-three patients were treated with an abbreviated course of radiotherapy (30 Gy in 6 fractions over 2 weeks) and 22 patients with the same radiotherapy schedule plus adjuvant temozolomide at the dose of 150-200 mg/m2 for 5 days every 28-day cycle. The primary end pointwas overall survival. Secondary end points included progression-free survival and toxicity. Results. Median overall survival was 7.3 months in the radiotherapy group and 9.4 months in the radiotherapy plus temozolomide group (P = 0.003), with respective 6-month overall survivals of 78% and 95%, respectively. Median progression-free survival was 4.4 months in the radiotherapy group and 5.5 months in the radiotherapy plus temozolomide group (P = 0.01), and respective 6-month progression-free survival rates were 22% and 45%. In multivariate analysis, Karnofsky performance score was the only significant independent predictive factor of survival (P = 0.03). Adverse effects of radiotherapy were mainly represented by neurotoxicity (24%), which resolved inmost cases with the use of steroids. Grade 3-4 hematologic toxicity occurred in 36% of patients treated with temozolomide. Conclusions. The addition of temozolomide to short-term radiotherapy resulted in a statistically significant survival benefit withminimal additional toxicity in poor-prognosis patients with newly diagnosed glioblastoma. Future studies need to define the best combined regimens of radiotherapy and temozolomide on survival and quality of life in this subgroup of patients. Free full text available at www.tumorionline.it

Phase II study of short-course radiotherapy plus concomitant and adjuvant temozolomide in elderly patients with glioblastoma

Purpose: Radiotherapy (RT) and chemotherapy may prolong survival in older patients (age ≥70 years) with glioblastoma multiforme (GBM), although the survival benefits remain poor. This Phase II multicenter study was designed to evaluate the efficacy and safety of an abbreviated course of RT plus concomitant and adjuvant temozolomide (TMZ) in older patients with GBM. Patients and Methods: Seventy-one eligible patients 70 years of age or older with newly diagnosed GBM and a Karnofsky performance status ≥60 were treated with a short course of RT (40 Gy in 15 fractions over 3 weeks) plus TMZ at the dosage of 75 mg/m 2 per day followed by 12 cycles of adjuvant TMZ (150-200 mg/m 2 for 5 days during each 28-day cycle). The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival and toxicity. Results: The Median OS was 12.4 months, and the 1-year and 2-year OS rates were 58% and 20%, respectively. The median and 1-year rates of progression-free survival were 6 months and 20%, respectively. All patients completed the planned programme of RT. Grade 3 or 4 adverse events occurred in 16 patients (22%). Grade 3 and 4 neutropenia and/or thrombocytopenia occurred in 10 patients (15%), leading to the interruption of treatment in 6 patients (8%). Nonhematologic Grade 3 toxicity was rare, and included fatigue in 4 patients and cognitive disability in 1 patient. Conclusions: A combination of an abbreviated course of RT plus concomitant and adjuvant TMZ is well tolerated and may prolong survival in elderly patients with GBM. Future randomized studies need to evaluate the efficacy and toxicity of different schedules of RT in association with chemotherapy. © 2012 Elsevier Inc. All rights reserved

Hypofractionated stereotactic radiotherapy in combination with bevacizumab or fotemustine for patients with progressive malignant gliomas

To evaluate the efficacy of hypofractionated stereotactic radiotherapy performed as reirradiation in combination with fotemustine or bevacizumab as salvage treatment in patients with recurrent malignant glioma. Between May 2006 and December 2013, 54 patients with recurrent malignant glioma received hypofractionated stereotactic radiotherapy (HSRT, 25 Gy in 5-Gy fractions) plus either fotemustine or bevacizumab at University of Rome Sapienza, Sant’Andrea Hospital. All patients had Karnofsky performance score (KPS) ≥ 60 and were previously treated with standard chemoradiotherapy. Forty-two patients had a GBM and 12 patients had an anaplastic astrocytoma (AA). The median overall survival (OS) time and 12-month OS rates after HSRT was 11 months and 30 % for patients treated with HSRT plus bevacizumab and 8.3 months and 5 % for those treated with HSRT plus fotemustine (p = 0.01). Median PFS times were 4 and 6 months for patients treated with HSRT plus fotemustine or bevacizumab, respectively (p = 0.01). KPS > 70 (p = 0.04), AA histology, and the treatment with bevacizumab were independent favourable prognostic factors for OS. In general, both treatments were well tolerated with relatively low treatment-related toxicity. HSRT combined with bevacizumab or fotemustine may represent a feasible treatment option for patients with progressive malignant gliomas, although most of the tumors recur in a few months. Efficacy of bevacizumab or alkylating agents in combination with different radiation schedules needs to be evaluated in prospective studies